Richard WEIR / Carl NELSON
EESTOR -- BaTi Ultra-Capacitor
Richard WEIR / Carl NELSON
EESTOR -- BaTi Ultra-Capacitor
http://thefraserdomain.typepad.com/energy/2006/01/eestor_ultracap.htmlJanuary 27, 2006 --- The Energy Blog
EEStor Ultracapacitor Shuns Publicity
Clean Break has an interesting post, much of what I have copied verbatim, on a new ultracapacitor made by start-up company EEStor of Austin TX. I thought the technology was potentially so important that a record of it was needed on the Energy Blog. The company is very wary of publicity and the following, which Tyler meticulously chased down, is about all that is known about their technology:
-- It is a parallel plate capacitor with barium titanate as the dielectric.
-- It claims that it can make a battery at half the cost per kilowatt-hour and one-tenth the weight of lead-acid batteries.
-- As of last year selling price would start at $3,200 and fall to $2,100 in high-volume production
-- The product weighs 400 pounds and delivers 52 kilowatt-hours.
-- The batteries fully charge in minutes as opposed to hours.
-- The EEStor technology has been tested up to a million cycles with no material degradation compared to lead acid batteries that optimistically have 500 to 700 recharge cycles,
Because it's a solid state battery rather than a chemical battery, such being the case for lithium ion technology, there would be no overheating and thus safety concerns with using it in a vehicle.-- With volume manufacturing it's expected to be cost-competitive with lead-acid technology.
-- As of last year, EEStor planned to build its own assembly line to prove the battery can work and then license the technology to manufacturers for volume production
-- EEStor's technology could be used in more than low-speed electric vehicles. The company envisions using it for full-speed pure electric vehicles, hybrid-electrics (including plug-ins), military applications, backup power and even large-scale utility storage for intermittent renewable power sources such as wind and solar.
-- They have an exclusive agreement with Feel Good Cars, a Canadian manufacturer of the ZENN, a low speed electric car, to to purchase high-power-density ceramic ultra capacitors called Electrical Storage Units (ESU). FGC's exclusive worldwide right is for all personal transportation uses under 15 KW drive systems (equivalent to 100 peak horse power) and for vehicles with a curb weight of under 1200 kilograms not including batteries.
None of these claims except construction and cost are significantly better than other ultracapacitors. Although they sometimes refer to the technology as a battery, it is clearly an ultracapacitor.
http://abcnews.go.com/Technology/Story?id=3547157&page=1
http://www.impactlab.com/modules.php?name=News&file=article&sid=12931September 01-07 Battery Breakthrough
Millions of inventions pass quietly through the U.S. patent office each year. Patent No. 7,033,406 did, too, until energy insiders spotted six words in the filing that sounded like a death knell for the internal combustion engine.
An Austin-based startup called EEStor promised "technologies for replacement of electrochemical batteries," meaning a motorist could plug in a car for five minutes and drive 500 miles roundtrip between Dallas and Houston without gasoline.
By contrast, some plug-in hybrids on the horizon would require motorists to charge their cars in a wall outlet overnight and promise only 50 miles of gasoline-free commute. And the popular hybrids on the road today still depend heavily on fossil fuels.
"It's a paradigm shift," said Ian Clifford, chief executive of Toronto-based ZENN Motor Co., which has licensed EEStor's invention. "The Achilles' heel to the electric car industry has been energy storage. By all rights, this would make internal combustion engines unnecessary."
Clifford's company bought rights to EEStor's technology in August 2005 and expects EEStor to start shipping the battery replacement later this year for use in ZENN Motor's short-range, low-speed vehicles.
The technology also could help invigorate the renewable-energy sector by providing efficient, lightning-fast storage for solar power, or, on a small scale, a flash-charge for cell phones and laptops.
Skeptics, though, fear the claims stretch the bounds of existing technology to the point of alchemy.
"We've been trying to make this type of thing for 20 years and no one has been able to do it," said Robert Hebner, director of the University of Texas Center for Electromechanics. "Depending on who you believe, they're at or beyond the limit of what is possible."
EEStor's secret ingredient is a material sandwiched between thousands of wafer-thin metal sheets, like a series of foil-and-paper gum wrappers stacked on top of each other. Charged particles stick to the metal sheets and move quickly across EEStor's proprietary material.
The result is an ultracapacitor, a battery-like device that stores and releases energy quickly.
Batteries rely on chemical reactions to store energy but can take hours to charge and release energy. The simplest capacitors found in computers and radios hold less energy but can charge or discharge instantly. Ultracapacitors take the best of both, stacking capacitors to increase capacity while maintaining the speed of simple capacitors.
Hebner said vehicles require bursts of energy to accelerate, a task better suited for capacitors than batteries.
"The idea of getting rid of the batteries and putting in capacitors is to get more power back and get it back faster," Hebner said.
But he said nothing close to EEStor's claim exists today.
For years, EEStor has tried to fly beneath the radar in the competitive industry for alternative energy, content with a yellow-page listing for an indiscriminate office building and a handful of cryptic press releases.
Yet the speculation and skepticism have continued, fueled by the company's original assertion of making batteries obsolete - a claim that still resonates loudly for a company that rarely speaks, including declining an interview with The Associated Press.
The deal with ZENN Motor and a $3 million investment by the venture capital group Kleiner Perkins Caufield & Byers, which made big-payoff early bets on companies like Google Inc. and Amazon.com Inc., hint that EEStor may be on the edge of a breakthrough technology, a "game changer" as Clifford put it.
ZENN Motor's public reports show that it so far has invested $3.8 million in and has promised another $1.2 million if the ultracapacitor company meets a third-party testing standard and then delivers a product.
Clifford said his company consulted experts and did a "tremendous amount of due diligence" on EEStor's innovation. EEStor's founders have a track record. Richard D. Weir and Carl Nelson worked on disk-storage technology at IBM Corp. in the 1990s before forming EEStor in 2001. The two have acquired dozens of patents over two decades.
Neil Dikeman of Jane Capital Partners, an investor in clean technologies, said the nearly $7 million investment in EEStor pales compared with other energy storage endeavors, where investment has averaged $50 million to $100 million.
Yet curiosity is unusually high, Dikeman said, thanks to the investment by a prominent venture capital group and EEStor's secretive nature.
"The EEStor claims are around a process that would be quite revolutionary if they can make it work," Dikeman said. Previous attempts to improve ultracapacitors have focused on improving the metal sheets by increasing the surface area where charges can attach.
EEStor is instead creating better nonconductive material for use between the metal sheets, using a chemical compound called barium titanate. The question is whether the company can mass-produce it.
ZENN Motor pays EEStor for passing milestones in the production process, and chemical researchers say the strength and functionality of this material is the only thing standing between EEStor and the holy grail of energy-storage technology.
Joseph Perry and the other researchers he oversees at Georgia Tech have used the same material to double the amount of energy a capacitor can hold. Perry says EEstor seems to be claiming an improvement of more than 400-fold, yet increasing a capacitor's retention ability often results in decreased strength of the materials.
"They're not saying a lot about how they're making these things," Perry said. "With these materials (described in the patent), that is a challenging process to carry out in a defect-free fashion."
Perry is not alone in his doubts. An ultracapacitor industry leader, Maxwell Technologies Inc., has kept a wary eye on EEStor's claims and offers a laundry list of things that could go wrong.
Among other things, the ultracapacitors described in EEStor's patent operate at extremely high voltage, 10 times greater than those Maxwell manufactures, and won't work with regular wall outlets, said Maxwell spokesman Mike Sund. He said capacitors could crack while bouncing down the road, or slowly discharge after a dayslong stint in the airport parking lot, leaving the driver stranded.
Until EEStor produces a final product, Perry said he joins energy professionals and enthusiasts alike in waiting to see if the company can own up to its six-word promise and banish the battery to recycling bins around the world.
"I am skeptical but I'd be very happy to be proved wrong," Perry said.
http://www.businessweek.com/the_thread/dealflow/archives/2005/09/kleiner_perkins_1.html
September 03, 2005
Kleiner Perkins' Latest Energy Investment
Justin Hibbard
Menlo Park, Calif. VC firm Kleiner Perkins Caufield & Byers in July led a $3 million preferred stock investment in EEStor Inc., a Cedar Park, Texas startup that is developing breakthrough battery technology.
The company was founded in 2001 by Richard D. Weir, Carl Nelson, and Richard S. Weir, who have backgrounds as senior managers in disk-storage technology at such companies as IBM and Xerox PARC. They previously co-founded disk-storage startup Tulip Memory Systems, where they won 16 U.S. patents.
According to a May, 2004 edition of Utility Federal Technology Opportunities, an obscure trade newsletter, EEStor claims to make a battery at half the cost per kilowatt-hour and one-tenth the weight of lead-acid batteries. Specifically, the product weighs 400 pounds and delivers 52 kilowatt-hours. (For battery geeks: "The technology is basically a parallel plate capacitor with barium titanate as the dielectric," UFTO says.) No hazardous or dangerous materials are used in manufacturing the ceramic-based unit, which means it qualifies as what Silicon Valley types call "cleantech."
As of last year, EEStor planned to build its own assembly line to prove the battery can work and then license the technology to manufacturers for volume production, UFTO says. Selling price would start at $3,200 and fall to $2,100 in high-volume production. Of course, all of this may have changed since KPCB got involved.
KPCB's investments are closely watched because the firm has made some of the most successful bets in VC history (Google, Amazon.com, Netscape, AOL, etc.). Energy investments carry a little extra risk for the firm since it is relatively new to the sector. Speaking at Stanford University in February, KPCB general partner John Doerr said the firm had made four energy investments so far, including fuel-cell maker Ion America. It will be interesting to watch how these companies develop.
http://www.treehugger.com/files/2006/03/eestor_capacito_1.php
EEStor Capacitors- "This could change everything"
March 6, 2006
Lloyd Alter, Toronto
Tyler Hamilton of the Toronto Star and website Clean Break has been digging around a very secretive company. Asking them for information they said: "EEStor is not making public statements at present time," company co-founder and chief executive Richard Weir replied when the Toronto Star requested an interview via email. "EEStor would also like to have you and your paper not publish any articles about our company and the Toronto Star is certainly not authorized to publish this response." which of course he published instantly in Canada's biggest newspaper, BoingBoing style. . What they are doing in Austin with their Kleiner Perkins Caufield & Byers money is developing a "parallel plate capacitor with barium titanate as the dielectric" or hypercapacitor as John recently coined. Says Tyler: "BusinessWeek reported an interesting comment from Kleiner's John Doerr, who recently spoke at a California event where tech VCs gather to make their predictions for the year. Doerr reportedly referred to an investment in an energy storage company he declined to name, calling it Kleiner's "Highest-risk, highest-reward" investment." Tyler's source describes it: (warning: if you continue reading you have to eat this post)
The batteries fully charge in minutes as opposed to hours.
Whereas with lead acid batteries you might get lucky to have 500 to 700 recharge cycles, the EEStor technology has been tested up to a million cycles with no material degradation.
EEStor's technology could be used in more than low-speed electric vehicles. The company envisions using it for full-speed pure electric vehicles, hybrid-electrics (including plug-ins), military applications, backup power and even large-scale utility storage for intermittent renewable power sources such as wind and solar.
Because it's a solid state battery rather than a chemical battery, such being the case for lithium ion technology, there would be no overheating and thus safety concerns with using it in a vehicle.
Finally, with volume manufacturing it's expected to be cost-competitive with lead-acid technology.
"It's the holy grail of battery technology," said my source. "It means you could do a highway capable electric city car that would recharge in three or four minutes and drive you from Toronto to Montreal. Consumers wouldn't notice the difference from driving an electric car versus a gas-powered car."
From his Star article:
Energy storage has long been the bottleneck for innovation, holding back new energy-sucking features in mobile devices and preventing everything from the electric car to renewable power systems from reaching their full potential. Build a radically better battery at lower cost, experts say, and the world we know will be forever transformed.
"There's been nothing big or disruptive, and we're due for it," says Nicholas Parker, chairman of the Cleantech Venture Network, which tracks investment in so-called clean technologies. He says energy storage is one of the hottest areas for venture capital funding right now. "Right across the board, better energy storage is essential."
Among EEStor's claims is that its "electrical energy storage unit" could pack nearly 10 times the energy punch of a lead-acid battery of similar weight and, under mass production, would cost half as much.
It also says its technology more than doubles the energy density of lithium-ion batteries in most portable computer and mobile gadgets today, but could be produced at one-eighth the cost.
If that's not impressive enough, EEStor says its energy storage technology is "not explosive, corrosive, or hazardous" like lead-acid and most lithium-ion systems, and will outlast the life of any commercial product it powers. It can also absorb energy quickly, meaning a small electric car containing a 17-kilowatt-hour system could be fully charged in four to six minutes versus hours for other battery technologies, the company claims.
According to patent documents obtained by the Star, EEStor's invention will do no less than "replace the electrochemical battery" where it's already used in hybrid and electric vehicles, power tools, electronic gadgets and renewable energy systems, from solar-powered homes to grid-connected wind farms.
"If everything they say is true, then that's pretty amazing," says MacMurray Whale, an energy analyst at Sprott Securities and a former professor of mechanical engineering at the University of Victoria. "To do all of that is unheard of when you look at any other battery technology out there."
Tyler Hamilton does not impress easily- he was not impressed with us for falling head over heels in love with the magenn turbine Don't bother googling for a website for EEStor- you will get a clothing site. But do read ::Clean Break and ::The Toronto Star before they send in the lawyers or break his fingers.
http://tyler.blogware.com/blog/_archives/2006/3/6/1799684.html
A Closer Look at the Promise of EEStor...
by Tyler Hamilton
Mon 06 Mar 2006
My Clean Break column in today's Toronto Star is actually an in-depth feature on Austin, Texas-based battery startup EEStor Inc., which claims to have developed an ultracapacitor with battery storage characteristics that has 10 times the energy density of a lead-acid battery and blows away current lithium-ion technology in all aspects of performance. EEStor also claims it can mass produce its product at a fraction of the cost of its lithium-ion rivals.
Is this the real deal? EEStor itself refused to be interviewed for my story, so I cobbled together a profile based on patent documents filed with the Canadian Intellectual Property Office. I also got my hands on an early investors' presentation from EEStor. While it's easy to be skeptical with this story, I point out in my piece that Kleiner Perkins' involvement lends serious credibility to this venture. I also found out that Morton Topfer, former vice-chairman of Dell Computer and Michael Dell's mentor, is on EEStor's board along with Michael Long, a well-seasoned executive and current CEO of real-estate giant Homestore Inc. So it seems there are some very credible people backing this tiny, secretive company.
Give the story a read. You decide whether this is snake oil or a technology that has disruptive potential.
Battery Power as Good as Gas?
A much-shrouded idea could give portable power a real charge, for a change — and change, well, everything
Mar. 6, 2006. 07:12 AM
TYLER HAMILTON
Imagine the day when cellphones charge up in seconds, laptop batteries never degrade, and electric cars have the same power, driving range and purchase price as their gas-powered cousins.
It's a consumer's dream and an engineer's fantasy: Safe, affordable and eco-friendly batteries that can store immense amounts of energy, allow for lightning-fast charging, and handle virtually unlimited discharging with little affect on quality.
Such a battery — a superbattery — doesn't exist today, but a tiny company out of Austin, Texas, is getting remarkably close, and the possibilities have caught the attention of the U.S. army, the former vice-chairman of Dell Computer, and one of the most respected venture capital firms in North America.
Not much is known about awkwardly named EEStor Inc., and the company prefers to keep it that way. It has no website. Hits on Google are remarkably low. And as far as requests from the media are concerned, the company makes its position crystal clear: Go away.
"EEStor is not making public statements at present time," company co-founder and chief executive Richard Weir replied when the Toronto Star requested an interview via email. "EEStor would also like to have you and your paper not publish any articles about our company and the Toronto Star is certainly not authorized to publish this response."
The Mission Impossible secrecy is understandable, given what's at stake. Despite advances in other fields, there have been no dramatic improvements in battery capacity in the two centuries since Italian physicist Alessandro Volta invented the technology.
Energy storage has long been the bottleneck for innovation, holding back new energy-sucking features in mobile devices and preventing everything from the electric car to renewable power systems from reaching their full potential. Build a radically better battery at lower cost, experts say, and the world we know will be forever transformed.
"There's been nothing big or disruptive, and we're due for it," says Nicholas Parker, chairman of the Cleantech Venture Network, which tracks investment in so-called clean technologies. He says energy storage is one of the hottest areas for venture capital funding right now. "Right across the board, better energy storage is essential."
Among EEStor's claims is that its "electrical energy storage unit" could pack nearly 10 times the energy punch of a lead-acid battery of similar weight and, under mass production, would cost half as much.
It also says its technology more than doubles the energy density of lithium-ion batteries in most portable computer and mobile gadgets today, but could be produced at one-eighth the cost.
If that's not impressive enough, EEStor says its energy storage technology is "not explosive, corrosive, or hazardous" like lead-acid and most lithium-ion systems, and will outlast the life of any commercial product it powers. It can also absorb energy quickly, meaning a small electric car containing a 17-kilowatt-hour system could be fully charged in four to six minutes versus hours for other battery technologies, the company claims.
According to patent documents obtained by the Star, EEStor's invention will do no less than "replace the electrochemical battery" where it's already used in hybrid and electric vehicles, power tools, electronic gadgets and renewable energy systems, from solar-powered homes to grid-connected wind farms.
"If everything they say is true, then that's pretty amazing," says MacMurray Whale, an energy analyst at Sprott Securities and a former professor of mechanical engineering at the University of Victoria. "To do all of that is unheard of when you look at any other battery technology out there."
EEStor's technology, to be accurate, isn't really a battery at all. In techie speak it's a ceramic ultracapacitor with a barium titanate dielectric. A mouthful to be sure, but what's important is that it's designed to combine the superior storage abilities of a battery with the higher power and discharge characteristics of an ultracapacitor.
Batteries, from the throwaway Energizer Bunny variety to the nickel-metal hydride units in a Toyota Prius, are great for storing large amounts of energy through chemical reactions, but they're notoriously slow when it comes to absorbing and releasing that energy.
They're also sensitive to temperatures, made up of toxic materials, and anyone who owns a digital camera, laptop, or handheld vacuum knows that after draining and recharging a few hundred times the battery degrades to the point of being useless.
On the other hand you've got ultracapacitors, based on an invention that dates back to 1745. These little devices hold energy as an electric charge and release it instantly as a power-packed jolt of electricity — not unlike the static shock you might get after walking on a rug and touching a metal doorknob. Ultracapacitors, unlike batteries, can also absorb a charge as fast as they release it.
And they're also "green," in the sense that they contain no nasty chemicals and aren't made of toxic substances. Reliable in the coldest winters and warmest summers, "ultracaps" can typically be cycled — that is, completely discharged and recharged — more than a million times, outlasting any iPod or that electric scooter in your garage.
"After nearly two centuries in which batteries have been the obvious choice for storing usable amounts of energy, high-end capacitors, known as ultracapacitors, are poised to challenge them in a growing range of applications," John Miller, an ultracap expert and former engineer with Ford Motor Co., wrote in a recent essay.
The quick power burst that ultracaps provide is why they're already showing up as a complement to batteries in hybrid-electric vehicles and fuel cells in hydrogen-powered cars and buses, which benefit from the extra kick that's needed to get from a stop-to-start position or to assist in acceleration.
But completely replacing batteries, rather than just complementing them, poses a much more difficult challenge. Ultracaps have traditionally not been able to store as much energy as a battery. For example, a lithium-ion battery — where many of the advances in the battery world are focused — can typically store 25 times more energy than the latest ultracapacitors of the same size made by market leaders such as Maxwell Technologies Inc., NessCap Co. Ltd., and Epcos AG.
Last month, researchers at the Massachusetts Institute of Technology announced they had achieved a breakthrough that could potentially overcome these energy-storage limitations. Using carbon nanotube structures, they claimed to have developed a way to improve by 100-fold the energy storage capacity of ultracapacitors.
Andrew Burke, an ultracap expert and researcher at the University of California at Davis, says there's no shortage of groundbreaking claims but no one has been able to back them up with hard data or outside a laboratory environment. And even if they get beyond the lab, the high cost of manufacturing presents another barrier to overcome.
"The stuff at MIT is a lot of hype," says Burke. "They haven't tested the material yet. Their claims are based on calculations and assumptions about what these things are going to do.
"I've been working on ultracaps since 1989, and I've seen an awful lot of water go under the bridge — a lot of technologies get hyped and then go away."
EEStor, on the other hand, appears well beyond the lab stage. Weir and Carl Nelson, vice-president of engineering and technology, spent much of the 1990s testing and developing manufacturing techniques and processes to support their claims.
Weir, an electrical engineer who has worked at IBM Corp. and autoparts giant TRW Inc., and Nelson, educated in chemistry and materials sciences, have extensive experience in the fabrication of integrated circuits and in the development of the kind of ceramic powder at the core of EEStor's technology.
The details of their research are sketchy, but it involves a method of processing, mass-producing and using barium titanate powder as an insulator — the dielectric — helping EEStor's energy storage system achieve a radical increase in voltage and energy storage without compromising reliability.
Another key to this process is the ability to lower the cost of production enough to become price-competitive with conventional battery technology, itself a major feat.
By 2000, the co-founders were ready to build a prototype. It's difficult to say how far EEStor's ultracap technology has evolved since, but sources close to the firm say a working prototype has been built and a production line is now creating prototypes on a batch basis, in preparation for volume production.
The company, sources say, is weeks away from seeking independent verification of the product's performance, which will be conducted by the University of Texas at Austin or a U.S. army facility. If all goes well, EEStor could be in preproduction this year and full production in 2007. During this time, potential customers — from automakers and military contractors to tool and electronics makers — will get a closer look at the product.
Burke remains skeptical. "I think it's nonsense. If they say they've built something I want to see the test data. Until then, talk is cheap."
Burke isn't the only suspicious observer. Another engineer the Star consulted had similar doubts. "Extraordinary claims require extraordinary proof," says Neil McMurchie, a freelance engineer working in the Alberta oil patch. "I find it hard to accept because the impact would be so profound. It would really change everything in electronics and power engineering."
Then again, he adds. "It just might work."
That possibility, that earth-shattering potential, has turned just as many skeptics into believers — a number of them highly credible. Last fall, it was reported that venture capital powerhouse Kleiner Perkins Caufield & Byers led a $3 million (U.S.) investment in EEStor.
Kleiner Perkins has a track record for picking winners. It made early bets on Google, Sun Microsystems, Amazon.com, Netscape and a host of other high-tech success stories that went on to become leaders of the computing, Web and telecommunications sectors.
"Kleiner has done a hell of a lot of due diligence on this," says a source close to EEStor, who asked not to be named.
John Doerr, a partner with Kleiner Perkins, reportedly told an audience at an investors' conference in January that an energy storage company, which he would not name, represented the VC's "highest-risk, highest-reward" investment. It's widely assumed he was referring to EEStor.
Adding more intrigue to the story is the fact that Colin Powell, the former U.S. secretary of state, joined Kleiner Perkins last summer as a strategic partner. Sources speculate Powell has been briefed on EEStor, which from a government and military perspective could bolster the Bush administration's energy security policy and efforts to break America's "addiction to oil."
"It's one thing to have the greatest new technology, but another to get it out into the field," says Richard Baxter, an energy-storage expert and researcher at New York-based Ardour Capital Investments LLC, who sees huge potential in ultracap technology. "Kleiner's great for opening up the door."
Besides Kleiner's involvement, EEStor has also attracted big names to its five-person board. The Star has learned that Morton Topfer, former vice-chairman of Dell Computer Corp. and widely known as Michael Dell's mentor, has joined the company as a director. Topfer founded and is managing director of Austin-based private equity firm Castletop Capital LP and has close and invaluable ties to big Texas money.
Michael Long, CEO of online real-estate giant Homestore Inc., is also on the board. His experience with Homestore and as CEO of several companies before that could prove useful as EEStor inches closer to commercialization.
There's a Canadian angle to all of this. Before Kleiner's involvement, EEStor struck a relationship with Toronto-based Feel Good Cars that has translated into a $2.5 million (U.S.) licensing agreement. Feel Good makes low-speed electric cars and wants to use EEStor's technology to power its next-generation vehicles, which could hit the market as early as 2007.
Ian Clifford, the company's co-founder and CEO, says he has secured exclusive worldwide rights to purchase EEStor's product for use in any vehicle up to 1,200 kilograms, about the size of a Honda Civic. It also has non-exclusive rights to use the technology in other vehicles excluding SUVs and pick-ups.
According to patent documents, EEStor describes the day when gas stations evolve into "electrical energy stations" that store energy overnight when electricity is cheap and sell it like gasoline during daytime. Drivers could pull in and recharge their EEStor-powered car in a few minutes the same way we now fill up with gasoline.
The company pegs the potential electric vehicle market at $40 billion (U.S.) a year, but figures its total opportunity — military, utility and electronics markets — approaches $150 billion.
Clifford is waiting anxiously for the results of independent testing, which are expected this spring and will trigger another licensing payment from Feel Good. "The implications of this technology go well beyond transportation," says Clifford. "EEStor, for us, would be a dream come true."
Clean Break reports on energy technologies. Reach Tyler Hamilton at thamilt@thestar.ca
http://yro.slashdot.org/article.pl?sid=08/12/22/0238227
EEStor Issued a Patent For Its Supercapacitor
December 22-08
An anonymous reader sends us to GM-volt.com, an electric vehicle enthusiast blog, for the news that last week EEStor was granted a US patent for their electric-energy storage unit, of which no one outside the company (no one who is talking, anyway) has seen so much as a working prototype. We've discussed the company on a number of occasions. The patent is a highly information-rich document that offers remarkable insight into the device. EEStor notes "the present invention provides a unique lightweight electric-energy storage unit that has the capability to store ultrahigh amounts of energy." "The core ingredient is an aluminum coated barium titanate powder immersed in a polyethylene terephthalate plastic matrix. The EESU is composed of 31,353 of these components arranged in parallel. It is said to have a total capacitance of 30.693 F and can hold 52.220 kWh of energy. The device is said to have a weight of 281.56 pound including the box and all hardware. Unlike lithium-ion cells, the technology is said not to degrade with cycling and thus has a functionally unlimited lifetime. It is mentioned the device cannot explode when being charge or impacted and is thus safe for vehicles."
US PATENT # 7466536Utilization of poly(ethylene terephthalate) plastic and composition-modified barium titanate powders in a matrix that allows polarization and the use of integrated-circuit technologies for the production of lightweight ultrahigh electrical energy storage units (EESU)
Also published as: WO2006026136 (A2) // WO2006026136 (A3) // EP1789980 (A2) // EP1789980
Abstract -- An electrical-energy-storage unit (EESU) has as a basis material a high-permittivity composition-modified barium titanate ceramic powder. This powder is single coated with aluminum oxide and then immersed in a matrix of poly(ethylene terephthalate) (PET) plastic for use in screen-printing systems. The ink that is used to process the powders via screen-printing is based on a nitrocellulose resin that provide a binder burnout, sintering, and hot isostatic pressing temperatures that are allowed by the PET plastic. These lower temperatures that are in the range of 40 DEG C. to 150 DEG C. also allows aluminum powder to be used for the electrode material.; The components of the EESU are manufactured with the use of conventional ceramic and plastic fabrication techniques which include screen printing alternating multilayers of aluminum electrodes and high-permittivity composition-modified barium titanate powder, sintering to a closed-pore porous body, followed by hot-isostatic pressing to a void-free body. The 31,351 components are configured into a multilayer array with the use of a solder-bump technique as the enabling technology so as to provide a parallel configuration of components that has the capability to store at least 52.22 kW.h of electrical energy. The total weight of an EESU with this amount of electrical energy storage is 281.56 pounds including the box, connectors, and associated hardware.
Current U.S. Class: 361/311 ; 361/301.4; 361/323
Current International Class: H01G 4/06 (20060101); H01G 4/30 (20060101)
Field of Search: 361/301.4,311-313,323Other References
Guardian, Inc. "Product Specification", no date. cited by examiner .
K.A. Nishimura, "NiCd Battery", Science Electronics FAQ V1.00: Nov. 10, 1996. cited by examiner .
Ovonics, Inc. "Product Data Sheet", no date. cited by examiner .
Evercel, Inc., "Battery Data Sheet--Model 100", no date. cited by examiner .
D. Corrigan et al, "Nickel Metal Hydride Batteries For ZEV-Range Hybrid Electric Vehicles", no date. cited by examiner .
B Dickinson et al, "Issues and Benefits with Fast Charging Industrial Batteries", AeroVeronment, Inc., no date. cited by examiner .
S. A. Bruno, et al., J. Am Ceram. Soc. 76, 1233 (1933). cited by examiner .
J. Kuwata et al, "Electric Properties of Perovskite-Type Oxide Thin-Films Prepared by RF Sputtering", Jpn J. Appl. Phys., Part 1, 1985, 24 (Suppl. 24-2, Proc. Int. Meet. Ferroelectr. 6th), 413-15. cited by examiner .
F. Sears et al, "Capacitance--Properties of Dielectrics", University of Physics, Addison Wesley Publishing Company, Inc., Dec. 1957: pp. 468-486. cited by examiner .
U.S. Appl. No. 09/833,609. cited by examiner .
Mistubishi Polyester Film Corporation specification sheet for Hostaphan (R) RE film for capacitors, Edition Nov. 2003. cited by examiner .
U.S. Appl. No. 11/499,594. cited by other .
U.S. Appl. No. 11/453,581. cited by other .
U.S. Appl. No. 11/497,744. cited by other .
Salvatore A. Bruno and Donald K. Swanson, "High-Performance Multilayer Capacitor Dielectrics from Chemically Prepared Powders," Journal of American Ceramic Society, vol. 76, No. 5, May 1993, pp. 1233-1241. cited by other .
Beheir et al., "Studies on the liquid-liquid extraction and ion and precipitate flotation of Co(II) with decanoic acid," Journal of Radioanalytical and Nuclear Chemistry, Articles, vol. 174, No. 1 (1992) 13-22. cited by other.Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to energy-storage devices, and relates more particularly to polarized high-permittivity ceramic powders immersed into a plastic matrix that has been used to fabricate components that are utilized in an array configuration for application in ultrahigh-electrical-energy storage devices.
2. Description of the Relevant Art
The internal-combustion-engine (ICE) powered vehicles have as their electrical energy sources a generator and battery system. This electrical system powers the vehicle accessories, which include the radio, lights, heating, and air conditioning. The generator is driven by a belt and pulley system and some of its power is also used to recharge the battery when the ICE is in operation. The battery initially provides the required electrical power to operate an electrical motor that is used to turn the ICE during the starting operation and the ignition system. The most common batteries in use today are flooded lead-acid, sealed gel lead-acid, Nickel-Cadmium (Ni--Cad), Nickel Metal Hydride (NiMH), and Nickel-Zinc (Ni--Z). References on the subject of electrochemical batteries include the following: Guardian, Inc., "Product Specification"; K. A. Nishimura, "NiCd Battery", Science Electronics FAQ V1.00: Nov. 20, 1996; Ovonics, Inc., "Product Data Sheet": no date; Evercel, Inc., "Battery Data Sheet--Model 100": no date; D. Corrigan, I. Menjak, B. Cleto, S. Dhar, S. Ovshinsky, Ovonic Battery Company, Troy, Mich., USA, "Nickle-Metal Hydride Batteries For ZEV-Range Hybrid Electric Vehicles"; B. Dickinson et al., "Issues and Benefits with Fast Charging Industrial Batteries", AeroVeronment, Inc. article: no date.
Each specific type of battery has characteristics, which make it either more or less desirable to use in a specific application. Cost is always a major factor and the NiMH battery tops the list in price with the flooded lead-acid battery being the most inexpensive. Evercel manufactures the Ni--Z battery and by a patented process, with the claim to have the highest power-per-pound ratio of any battery. See Table 1 below for comparisons among the various batteries. What is lost in the cost translation is the fact that NiMH batteries yield nearly twice the performance (energy density per weight of the battery) than do conventional lead-acid batteries. A major drawback to the NiMH battery is the very high self-discharge rate of approximately 5 to 10% per day. This would make the battery useless in a few weeks. The Ni--Cad battery as does the lead-acid battery also have self-discharge but it is in the range of about 1% per day and both contain hazardous materials such as acid or highly toxic cadmium. The Ni--Z and the NiMH batteries contain potassium hydroxide and this electrolyte in moderate and high concentrations is very caustic and will cause severe burns to tissue and corrosion to many metals such as beryllium, magnesium, aluminum, zinc, and tin.
Another factor that must be considered when making a battery comparison is the recharge time. Lead-acid batteries require a very long recharge period, as long as 6 to 8 hours. Lead-acid batteries, because of their chemical makeup, cannot sustain high current or voltage continuously during charging. The lead plates within the battery heat rapidly and cool very slowly. Too much heat results in a condition known as "gassing" where hydrogen and oxygen gases are released from the battery's vent cap. Over time, gassing reduces the effectiveness of the battery and also increases the need for battery maintenance, i.e., requiring periodic deionized or distilled water addition. Batteries such as Ni--Cad and NiMH are not as susceptible to heat and can be recharged in less time, allowing for high current or voltage changes which can bring the battery from a 20% state of charge to an 80% state of charge in as quick as 20 minutes. The time to fully recharge these batteries can take longer than an hour. Common to all present day batteries is a finite life and if they are fully discharged and recharged on a regular basis their life is reduced considerably.
SUMMARY OF THE INVENTION
In accordance with the illustrated preferred embodiment, the present invention provides a unique lightweight electrical-energy-storage unit that has the capability to store ultrahigh amounts of energy.
The basis material, an aluminum oxide coated high-permittivity calcined composition-modified barium titanate powder which is a ceramic powder described in the following references: S. A. Bruno, D. K. Swanson, and I. Burn, J. Am. Ceram. Soc. 76, 1233 (1993); P. Hansen, U.S. Pat. No. 6,078,494, issued Jun. 20, 2000, and U.S. patent application Ser. No. 09/833,609, is used as the energy storage material for the fabrication of the electrical energy storage units (EESU).
Yet another aspect of the present invention is that the alumina-coated calcined composition-modified barium titanate (alumina-coated calcined CMBT) powder and the immersion of these powders into a poly(ethylene terephthalate) plastic matrix provides many enhancement features and manufacturing capabilities to the basis material. The alumina-coated calcined CMBT powder and the poly(ethylene terephthalate) plastic have exceptional high-voltage breakdown and when used as a composite with the plastic as the matrix the average voltage breakdown was 5.57.times.10.sup.6 V/cm or higher. The voltage breakdown of the poly(ethylene terephthalate) plastic is 580 V/.mu.m at 23.degree. C. and the voltage breakdown of the alumina-coated CMBT powders is 610 V/.mu.m at 85.degree. C. The following reference indicates the dielectric breakdown strength in V/cm of composition-modified barium titanate materials: J. Kuwata et al., "Electrical Properties of Perovskite-Type Oxide Thin-Films Prepared by RF Sputtering", Jpn. J. Appl. Phys., Part 1, 1985, 24(Suppl. 24-2, Proc. Int. Meet. Ferroelectr., 6.sup.th), 413-15. The following reference indicates the dielectric breakdown strength in V/.mu.m of poly(ethylene terephthalate) materials: Mitsubishi Polyester Film corporation specification sheet for .RTM.Hostaphan RE film for capacitors, Edition 11/03. This very-high-voltage breakdown assists in allowing the ceramic EESU to store a large amount of energy due to the following: Stored energy E=CV.sup.2/2, Formula 1, as indicated in F. Sears et al., "Capacitance--Properties of Dielectrics", University Physics, Addison-Wesley Publishing Company, Inc.: December 1957: pp 468-486, where C is the capacitance, V is the voltage across the EESU terminals, and E is the stored energy. This indicates that the energy of the EESU increases with the square of the voltage. FIG. 1 indicates that a double array of 31,351 energy storage components 9 in a parallel configuration that contains the alumina-coated calcined composition-modified barium titanate powder. Fully densified ceramic components of this powder coated with 100 .ANG. of aluminum oxide (alumina) 8 and a 100 .ANG. of poly(ethylene terephthalate) plastic as the matrix 8 with a dielectric thickness of 9.732 .mu.m can be safely charged to 3500 V. The number of components used in the double array depends on the electrical energy storage requirements of the application. The components used in the array can vary from 2 to 10,000 or more. The total number of components used in the arrays for the example of this invention was 31,351. The total capacitance of these particular arrays 9 was 30.693 F which will allow 52,220 Wh of energy to be stored as derived by Formula 1.
The alumina-coated calcined CMBT powder and the poly(ethylene terephthalate) plastic matrix also assist in significantly lowering the leakage and aging of ceramic components comprised of the calcined composition-modified barium titanate powder to a point where they will not affect the performance of the EESU. In fact, the discharge rate of the EESU will be lower than 0.1% per 30 days which is approximately an order of magnitude lower than the best electrochemical battery.
A significant advantage of the present invention is that the PET plastic matrix assists in lowering the sintering temperature to 150.degree. C. and hot-isostatic-pressing temperatures to 180.degree. C. and the required pressure to 100 bar. These lower temperatures eliminate the need to use very expensive platinum, palladium, palladium-silver alloy, or less expensive but still costly nickel powders as the terminal metal. In fact, these temperatures are in a safe range that allows aluminum, the fourth best conductor, to be used for the electrodes, providing a major cost saving in material expense and also power usage during the hot-isostatic-pressing process. Aluminum as a metal is not hazardous. The lower pressure provides low processing cost for the hot-isostatic-pressing step. Also, since the PET plastic becomes easily deformable and flowable at these temperatures, voids are readily removed from the components during the hot-isostatic-pressing process. A manufacturer of such hot-isostatic-pressing ovens is Material Research Furnances Inc. For the EESU product to be successful it is mandatory that all voids be eliminated so that the high-voltage breakdown can be obtained. Also, the method described here of using the poly(ethylene terephthalate) plastic as the matrix for the high-relativity-permittivity alumina-coated composition-modified barium titanate powder ensures the hot-isostatic-pressing results in layers that are uniform homogeneous and void free.
None of the EESU materials used to fabricate the EESU, which are aluminum, aluminum oxide, copper, composition-modified barium titanate powder, silver-filled epoxy, and poly(ethylene terephthalate) plastic will explode when being recharged or impacted. Thus the EESU is a safe product when used in electric vehicles, buses, bicycles, tractors, or any device that is used for transportation or to perform work, portable tools of all kinds, portable computers, or any device or system that requires electrical energy storage. It could also be used for storing electrical power generated from electrical energy generating plants, solar voltaic cells, wind-powered electrical energy generating units, or other alternative sources on the utility grids of the world for residential, commercial, or industrial applications. The power averaging capability of banks of EESU devices with the associated input/output converters and control circuits will provide significant improvement of the utilization of the power generating plants and transmission lines on the utility grids of the world. The EESU devices along with input/output converters and control circuits will also provide power averaging for all forms of alternative energy producing technology, but specifically wind and solar will have the capability to provide constant electrical power due to the EESU storing sufficient electrical energy that will meet the energy requirements of residential, commercial, and industrial sites. In fact, wind could become a major source of electrical energy due to the capability of the EESU technology to convert wind from a peak provider, i.e., when the wind blows and power is needed it is used, to a cost-effective primary electrical energy supplier, such as are coal-fired plants.
Yet another aspect of the present invention is that each component of the EESU is produced by screen-printing multiple layers of aluminum electrodes with screening ink from aluminum powder. Interleaved between aluminum electrodes are dielectric layers with screening ink from calcined alumina-coated high-permittivity composition-modified barium titanate powder immersed in poly(ethylene terephthalate) plastic as the matrix. A unique independent dual screen-printing and layer-drying system is used for this procedure. Each screening ink contains appropriate amounts of nitrocellulose, glycerol, and isopropyl alcohol, resulting in a proper rheology for screen printing each type of layer: the aluminum electrode, the alumina-coated composition-modified barium titanate ceramic powder immersed in the poly(ethylene terephthalate) plastic dielectric, and the poly(ethylene terephthalate) plastic dielectric by itself. The number of these layers can vary depending on the electrical energy storage requirements. Each layer is dried; the binder burned out, and sintered before the next layer is screen-printed. Each aluminum electrode layer 12 is alternately offset to each of two opposite sides of the component automatically during this process as indicated in FIG. 2. These layers are screen-printed on top of one another in a continuous manner. When the specified number of layers is achieved, the array is cut into individual components to the specified sizes. In the example, the size is length=0.508 cm and the width 1.143 cm with an area=0.581 cm.sup.2.
After each screen-printing operation in which a green sheet is fabricated having either 1 .mu.m for the final thickness of the aluminum layers or 9.732 .mu.m for the final thickness of the dielectric layer, or final thicknesses for the aluminum and dielectric layers that are suitable for the particular application, a drying, binder-burnout, and sintering operation is completed. The oven has multiple temperature zones that range from 40.degree. C. to 125.degree. C. and the green sheets are passed through these zones at a rate that avoids any cracking and delamination of the body. After this process is completed the components are then properly prepared for the hot isostatic pressing (HIP) at 180.degree. C. and 100 bar pressure. The HIP processing time was 45 minutes which included a 10 minute temperature ramp time and a 5 minute cooldown time. This process eliminated all voids. After this process the components are then abrasively cleaned on the connection side to expose the alternately offset interleaved aluminum electrodes 12. Then aluminum end caps 14 are bonded onto each end component 15 that has the aluminum electrodes exposed with the use of a silver-filled epoxy resin as the adhesive. The components are then cured at 100.degree. C. for 10 minutes to bond the aluminum end caps to the components as indicated in FIG. 3. The next step involves polarizing the components. As many as 6000 components are held in a tool. This holding tool is then placed into a fixture that retains the components between anode and cathode plates. Each anode and cathode is spring-loaded to ensure electrical contact with each component. The fixture is then placed into an oven where the processing temperature is increased to 180.degree. C. over a period of 20 minutes. At the temperature of 180.degree. C., voltages of -2000 V is applied to the cathode plates and +2000 V is applied to the anode plates, or voltages selected for the particular dielectric thickness, for a period of 5 minutes. At the completion of this process the alumina-coated composition-modified barium titanate powder immersed within the poly(ethylene terephthalate) plastic matrix will be fully polarized. The components are then assembled into a first-level array, FIG. 3, with the use of the proper tooling. The aluminum end caps are bonded onto the copper plates with silver filled epoxy resin. Then the first-level arrays are assembled into a second-level array, FIG. 4, by stacking the first array layers on top of one another in a preferential mode. This process is continued until sufficient numbers of arrays are stacked to obtain the desired energy storage for the particular EESU that is being produced. Then copper bars 18 are attached on each side of the arrays as indicated in FIG. 4. Then the EESU is packaged into its final assembly.
The features of this invention indicate that the EESU, as indicated in Table 1, outperforms the electrochemical battery in every parameter. This technology will provide mission-critical capability to many sections of the energy-storage industry.
TABLE-US-00001 TABLE 1 The parameters of each technology to store 52.22 kW h of electrical energy are indicated - (data from manufacturers' specification sheets). EESU NiMH LA (Gel) Ni-Z Li-Ion Weight 286.56 1716 3646 1920 752 (pounds) Volume (inch.sup.3) 4541 17,881 43,045 34,780 5697 Discharge rate/ 0.1% 5% 1% 1% 1% 30 days Charging time *3-6 min 1.5 hr 8.0 hr 1.5 hr 6.0 hr (full) Life reduced none moderate high moderate high with deep cycle use Hazardous NONE YES YES YES YES materials *The charging time is restricted by the converter circuits not the EESU.
This EESU will have the potential to revolutionize the electric vehicle (EV) industry, provide effective power averaging for the utility grids, the storage and use of electrical energy generated from alternative sources with the present utility grid system as a backup source for residential, commercial, and industrial sites, the electric energy point of sales to EVs, provide mission-critical power storage for many military programs. The EESU will replace the electrochemical battery in any of the applications that are associated with the above business areas.
The features and advantages described in the specifications are not all inclusive, and particularly, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the description, specification and claims hereof. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter, resort to the claims being necessary to determine such inventive subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 indicates a schematic of 31,351 energy storage components 9 hooked up in parallel with a total capacitance of 30.693 F. The maximum charge voltage 8 of 3500 V is indicated with the cathode end of the energy storage components 9 hooked to system ground 10.
FIG. 2 is a cross-section side view of the electrical-energy-storage unit component. This figure indicates the alternating layers of aluminum electrode layers 12 and high-permittivity composition-modified barium titanate dielectric in a poly(ethylene terephthalate) plastic matrix developed into layers 11. This figure also indicates the alternately offset aluminum electrode layers 12 so that each storage layer is connected in parallel.
FIG. 3 is side view of a single-layer array indicating the attachment of individual components 15 with the aluminum end caps attached by silver-filled epoxy resin 14 attached to two opposite polarity copper conducting sheets 13.
FIG. 4 is a side view of a double-layer array with copper array connecting aluminum end caps bonded with silver-filled epoxy resin 16 and then attaching the two arrays via the edges of the opposite polarity copper conductor sheets 13. This figure indicates the method of attaching the components in a multilayer array to provide the required energy storage.
REFERENCE NUMERALS IN DRAWING
8 System maximum voltage of 3500 V 9 31,351 energy-storage components hooked up in parallel with a total capacitance of 30.693 F 10 System ground 11 High-permittivity calcined alumina-coated composition-modified barium titanate powder dispersed in poly(ethylene terephthalate) plastic matrix dielectric layers 12 Alternately offset aluminum electrode layers 13 Copper conductor sheets 14 Aluminum end caps 15 Components 16 Copper array connecting aluminum end caps
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1, 2, 3, and 4 of the drawings and the following description depict various preferred embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following discussion those alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to those embodiments. On the contrary, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the invention as defined by the claims.
The screen printing of the alumina-coated composition-modified barium titanate powder and poly(ethylene terephthalate) plastic powder mixture as an ink requires that the particle sizes of these two components be nearly the same. In the example, the average particle size was 0.64 .mu.m. Since the poly(ethylene terephthalate) plastic is not available in powder form, but only as pellets, these pellets must be pulverized to submicron-sized powder. The plastic being relatively soft must be cryogenically embrittled so that it will fragment by impact shattering.
Similarly, aluminum powder is available at economical pricing in particle sizes that are too large for this application. However, in the same way as described for the poly(ethylene terephthalate) (PET) plastic pellets, aluminum being a relatively soft metal, its powder can be embrittled cryogenically and then fragmented by impact shattering.
Systems to accomplish this task have been developed for cryogenic freezing of the plastic pellets and the aluminum powders: the Air Products Process Cooling System, and for impact jet pulverizing of these cryogenic-frozen pellets and the aluminum powder: the Micron-Master jet mill manufactured by The Jet Pulverizer Company.
The binder for the screen-printing ink consists of the lowest-decomposition-temperature resin: nitrocellulose and two solvents for the resin: glycerol and isopropyl alcohol, the former being more viscous than the latter, so that the proper screen-printing rheology can be easily adjusted.
Three screen-printing inks are required:
1. poly(ethylene terephthalate) plastic powder, alumina-coated composition-modified barium titanate ceramic powder, and the binder. 2. poly(ethylene terephthalate) plastic powder and the binder 3. aluminum metal powder and the binder
For the case of the first screen-printing ink with respect to the volume ratio of the plastic powder to the ceramic powder, this ratio can range from 35/65 to 6/94. The high-relative-permittivity dielectric layers are formed from this ink with final thicknesses after hot isostatic pressing ranging from 5 to 20 .mu.m. With the second screen-printing ink, the surrounding low-relative-permittivity dielectric layers are formed of equal final thickness to the high-relative-permittivity layers or the aluminum electrode layers. The purpose of these layers is to avoid electric-field fringing at the edges of the high-relative-permittivity layers. With the third screen-printing ink, the aluminum electrodes are formed with final thickness after hot isostatic pressing ranging from 1 to 2 .mu.m.
The screen-printing of the materials for the multilayer capacitor array requires the plastic, ceramic, and metal powders to be comparable particle size. Since the ceramic powder is in-situ coprecipitated from aqueous solution as submicron in size, commercially available poly(ethylene terephthalate) plastic pellets and aluminum powder have to be reduced in size. These relatively soft materials must be cooled to cryogenic temperatures to enable embrittlement to occur. Then by jet impact of the chilled materials, shattering occurs. With several passes of the chilled material through the jet pulverizer the particles are reduced to submicron size.
The chilling of the material is carried out in a cryogenic cooling conveyer that cool the poly(ethylene terephthalate) plastic pellets to -150.degree. C. This conveyer is then the feeder of the chilled material to the air jet pulverizer.
A basis layer of the plastic powder and binder is screen-printed onto a flat Teflon.RTM. polytetrafluoroethylene plastic-coated stainless steel plate, this first layer serving as a substrate and dielectric layer isolating the next aluminum electrode layer from contact with the outside. The Teflon.RTM. plastic coating on the stainless steel plates keeps the elements from sticking to the plate surface during the heat treatment of the green sheets after each screen-printing step.
The next layer comprised of aluminum powder and binder is screen-printed onto the first layer with a stencil, this second layer serving as the electrode and is offset to one end of the dielectric layer.
As part of the second layer and surrounding the electrodes layer on three of its sides, a layer of plastic powder and binder is screen-printed with a stencil onto the first layer.
A third layer of plastic powder, ceramic powder, and binder is screen-printed onto the second layer with a stencil, this third layer serving as the active dielectric layer.
As part of the third layer and surrounding the active dielectric layer on all four of its sides, a layer of plastic powder and binder is screen-printed with a stencil onto the second layer.
A fourth layer of aluminum powder and binder is screen-printed with a stencil onto the third layer, this fourth layer serving as the opposite electrode to the active dielectric layer and is offset to the opposite end of the dielectric layer.
As part of the fourth layer and surrounding the electrode layer on three of its sides, a layer of plastic powder and binder is screen-printed with a stencil onto the third layer.
This collection of steps except the first step is repeated any number of times, anywhere from one to a thousand. Arrays of 100 dielectric and electrode layers were used to produce elements for the proof-of-concepts development. In this fashion the multilayer array is built up.
The last concluding step is a repeat of the first step.
After each screen-printing step the Teflon.RTM. plastic-coated stainless steel plate containing the just-deposited green sheet is processed by an inline oven. This oven provides two functions with the first being binder burnout and the second being the sintering and densification to the closed pore porous condition. This oven has multiple heating zones with the first zone at temperature of 40.degree. C. and the last zone at temperature of 150.degree. C. The time for the elements to be processed through these zones will depend on the thickness of the green layer, but was in the range of 10 seconds for the electrode layers and 60 seconds for the dielectric layers for the elements fabricated for the example of this invention. The processing time must be selected to ensure that the green layers do not destructively crack and rupture.
The screen-printed sheets of the multilayer elements are diced into individual elements. The elements dimensions are 0.508 cm by 1.143 cm.
The elements are then placed into the indentations of Teflon.RTM. plastic-coated stainless steel trays. The trays have the capability to hold 6,000 elements. The Teflon.RTM. plastic coating prevents the elements from sticking to the stainless steel tray. The trays containing the elements are then inserted into a hot isostatic pressing (HIP) oven capable of 100 bar pressure with clean dry air and 180.degree. C. temperature is employed. The processing time of this HIP process is 45 minutes which includes a 10 minute temperature ramp up time and a 5 minute cooldown time.
Then ten elements are then bonded together with an adhesive having a curing temperature of 80.degree. C. for duration of 10 minutes.
After completion of the bonding step the aluminum electrode layers at two opposite ends of the multilayer array are connected to one another of the same side after these sides have been abrasively cleaned to expose the aluminum electrodes. A high-conductivity silver-loaded epoxy resin paste with elastomeric characteristic (mechanical shock absorption) is selected to connect the aluminum electrode layers of the multilayer array to the aluminum end caps for attachment by silver-filled epoxy resin.
The completed multilayer components are poled by applying a polarizing electric field across each of the active dielectric layers. Since there layers are electrically parallel within each multilayer array and that these multilayer arrays can be connected in parallel, the applied voltage to accomplish the polarizing electric field can be as high as the working voltage. The components are heated in an oven to at least 180.degree. C. before the polarizing voltage is applied. A temperature of 180.degree. C. and applied voltages of +2000 V and -2000 V for a duration of 5 minutes were utilized in the example of this invention.
Ink Slurry Mixer and Disperser
The ink slurry mixer and disperser is comprised of a polyethylene plastic or polypropylene plastic tank, a Teflon.RTM. polytetrafluoroethylene-plastic-coated stainless steel paddle mixer, ultrasonic agitation, and multiple recirculating peristaltic pumps with the associated tubing. The slurry as multiple streams are recirculated from the tank bottom and at the tank top reintroduced with the multiple streams oppositely directed toward on another. This high impact of the powders in these multiple streams will ensure that any retained charges are released, thus providing a well-dispersed ink free of agglomerates suitable for screen printing.
Ink Delivery to the Screen Printer
Each of the three screen-printing inks is delivered to the appropriate stations of the screen-printing system. Peristaltic pumps with their associated plastic tubing are used to convey the inks from the polyethylene plastic or polypropylene plastic tanks employed for ink making to a line manifold with several equal-spaced holes located at one edge of each printing screen, so as to distribute the ink uniformly at this edge. Higher pressure peristaltic pumps are used so that essentially all the pressure drop occurs at the manifold hole exits.
Example
The electrical-energy-storage unit's weight, stored energy, volume, and configuration design parameters
The relative permittivity of the high-permittivity powder to be achieved is 21,072. The 100 .ANG. coating of Al.sub.2O.sub.3 and 100 .ANG. of poly(ethylene terephthalate plastic will reduce the relative permittivity by 12%. The resulting K=18,543
Energy stored by a capacitor: E=CV.sup.2/(2.times.3600 s/h)=Wh C=capacitance in farads (F) V=voltage across the terminals of the capacitor It is estimated that is takes 14 hp, 746 W per hp, to power an electric vehicle running at 60 mph with the lights, radio, and air conditioning on. The energy-storage unit must supply 52,220 Wh or 10,444 W for 5 hours to sustain this speed and energy usage and during this period the EV will have traveled 300 miles. Design parameter for energy storage--W=52.22 kWh Design parameter for working voltage--V=3500 V Resulting design parameter of capacitance--C=30.693 F
C=.di-elect cons..sub.0KA/t .di-elect cons..sub.0=permittivity of free space K=relative permittivity of the material A=area of the energy-storage component layers t=thickness of the energy-storage component layers Test data of materials, layers, cells, elements, developed components, and the final EESU. The area of the element, which has 100 cells (capacitors) screen-printed layers, is as follows: Area=0.508 cm.times.1.143 cm=0.5806 cm.sup.2 The resulting design parameter for dielectric layer thickness--t=9.732.times.10.sup.-4 cm Volume of the dielectric layer=0.5806 cm.sup.2.times.9.732.times.10.sup.-4 cm=0.0005651 cm.sup.3 Weight of the alumina-coated composition-modified barium titanate powder=(0.0005651 cm.sup.3.times.1000.times.31,351.times.6.5 g/cm.sup.3.times.0.94)=238.43 pounds Weight of the poly(ethylene terephthalate) powder=(0.0005651 cm.sup.3.times.1000.times.31,351.times.1.4 g/cm.sup.3.times.0.04)=2.185 pounds The electrode layer thickness=1 .mu.m Volume of the electrode=0.5806 cm.sup.2.times.1 .mu.m=5.806.times.10.sup.-5 cm.sup.3 Weight of the aluminum powder=(5.806.times.10.sup.-5 cm.sup.3.times.1010.times.31,351.times.2.7 g/cm.sup.3)=10.93 pounds Total weight of the EESU including the box, connectors, and associated hardware Wt=281.56 pounds Capacitance of one component=(8.854.times.10.sup.-12 F/m.times.1.8543.times.10.sup.-4.times.5.806.times.10.sup.-5 m.sup.2/9.73.times.10.sup.-6 m).times.10 elements.times.100 cells=0.000979 F Number of components required to store 52.22 kWh of electrical energy: N.sub.c=30.693 F/0.000979 F=31,351.379.apprxeq.31,351 The following data indicates the results of pulverizing the poly(ethylene terephthalate) plastic pellets.
TABLE-US-00002 % Volume Size in .mu.m 0.25 .2 0.35 .3 2.1 .4 15 .5 58.55 .6 16 .7 5 .8 0.25 1 Average size of the PET plastic powder is 0.64 .mu.m.
The following data indicates the results of the pulverizing of the aluminum powder
TABLE-US-00003 % volume Size in .mu.m .12 .05 .7 .07 2.5 1.2 17 1.9 59.5 2.3 16 2.9 3.1 3.4 .41 3.9 Average aluminum particle size = 2.4 .mu.m
The following data indicates the relativity permittivity of ten single-coated composition-modified barium titanate powder batches.
TABLE-US-00004 Batches Relativity Permittivity @ 85.degree. C. 1. 19,901 2. 19,889 3. 19,878 4. 19,867 5. 19,834 6. 19,855 7. 19,873 8. 19,856 9. 19,845 10. 19,809 Average relativity permittivity = 19,861
The following data indicates the relativity permittivity of ten components measured at 85.degree. C., then 85.degree. C. and 3500 V, and the last test 85.degree. C. and 5000 V.
TABLE-US-00005 Components 85.degree. C. 85.degree. C.-3500 V 85.degree. C.-5000 V 1. 19,871 19,841 19,820 2. 19,895 19,866 19,848 3. 19,868 19,835 19,815 4. 19,845 19,818 19,801 5. 19,881 19,849 19,827 6. 19,856 19,828 19,806 7. 19,874 19,832 19,821 8. 19,869 19,836 19,824 9. 19,854 19,824 19,808 10. 19,877 19,841 19,814 Average K 19,869 19,837 19,818
Results indicates that the composition-modified barium titanate powder that has been coated with 100 .ANG. of Al.sub.2O.sub.3, immersed into a matrix of PET plastic, and has been polarized provides a dielectric saturation that is above the 5000 V limit and the relative permittivity is highly insensitive to both voltage and temperature. Leakage current of ten EESUs that contain 31,351 components each and having the capability of storing 52.22 kWh of electrical energy measured at 85.degree. C. and 3500 V.
TABLE-US-00006 EESU Leakage Current - .mu.A 1. 4.22 2. 4.13 3. 4.34 4. 4.46 5. 4.18 6. 4.25 7. 4.31 8. 4.48 9. 4.22 10. 4.35 Average leakage current 4.28
Voltage breakdown of ten components with and average dielectric thickness of 9.81 .mu.m measured at a temperature of 85.degree. C.
TABLE-US-00007 Component Voltage Breakdown - 10.sup.6 V/cm 1. 5.48 2. 5.75 3. 5.39 4. 5.44 5. 5.36 6. 5.63 7. 5.77 8. 5.37 9. 5.64 10. 5.88 Average voltage breakdown 5.57
Full charge/discharge cycles of a component from 3500 V to 0 V at 85.degree. C. After each 100,000 cycles the leakage current was recorded. The leakage current was multiplied by 31,351 to reflect the full EESU value. The rise time on the charging voltage was 0.5 seconds and the discharge time was 1.0 seconds. The RC time constant was 0.11 seconds for both the charging and the discharging times. The voltage breakdown was tested at the end of 10.sup.6 cycles and was measured at 85.degree. C. with the results being 5.82.times.10.sup.6 V/cm and the total capacitance was measured at 30.85 F. The final test data indicates that the full cycle testing did not degrade the total capacitance, leakage, or voltage breakdown capabilities of the component.
TABLE-US-00008 Test cycle Leakage Current - .mu.A 1. 4.29 2. 4.28 3. 4.21 4. 4.38 5. 4.30 6. 4.42 7. 4.31 8. 4.26 9. 4.46 10. 4.41
From the above description, it will be apparent that the invention disclosed herein provides a novel and advantageous electrical-energy-storage unit composed of unique materials and processes. The foregoing discussion discloses and describes merely exemplary methods and embodiments of the present invention. As will be understood by those familiar with the art, the invention may be embodied in other specific forms and utilize other materials without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
\
US Patent # 7,033,406
Electrical-Energy-Storage Unit (EESU) Utilizing Ceramic and Integrated-Circuit Technologies for Replacement of Electrochemical Batteries
April 25, 2006
Weir, Richard D. (Cedar Park, TX); Nelson, Carl W. (Austin, TX)
US Cl. 29/623.5 ; 29/623.1
Intl. Cl. H01M 6/00 (20060101)Abstract
An electrical-energy-storage unit (EESU) has as a basis material a high-permittivity composition-modified barium titanate ceramic powder. This powder is double coated with the first coating being aluminum oxide and the second coating calcium magnesium aluminosilicate glass. The components of the EESU are manufactured with the use of classical ceramic fabrication techniques which include screen printing alternating multilayers of nickel electrodes and high-permittivitiy composition-modified barium titanate powder, sintering to a closed-pore porous body, followed by hot-isostatic pressing to a void-free body. The components are configured into a multilayer array with the use of a solder-bump technique as the enabling technology so as to provide a parallel configuration of components that has the capability to store electrical energy in the range of 52 kWh. The total weight of an EESU with this range of electrical energy storage is about 336 pounds.
References Cited:
U.S. Patent Documents: 5711988 ~ 5738919 ~ 5744258 ~ 5797971 ~ 5800857 ~ 5850113 ~ 5850113 ~ 5867363 ~ 5973913 ~ 6005764 ~ 6078494 ~ 6243254 ~ 6268054
Foreign Patent Documents: JP11147716 ~ WO 93/16012
Other References:
SA. Bruno, D.K. Swanson & I. Burns, High-Performance Multilayer Capacitor Dielectric from Chemically Prepared Powders J. Am. Ceram Soc 76, 1233 (1993). cited by other .
J. Kuwata et al, "Electrical Properties of Perovskite-Type Oxide Thin-Films Prepared by RFSputtering" Jpn J. cited by other.BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to energy-storage devices, and relates more particularly to high-permittivity ceramic components utilized in an array configuration for application in ultrahigh-electrical-energy storage devices.
2. Description of the Relevant Art
The internal-combustion-engine (ICE) powered vehicles have as their electrical energy sources a generator and battery system. This electrical system powers the vehicle accessories, which include the radio, lights, heating, and air conditioning. The generator is driven by a belt and pulley system and some of its power is also used to recharge the battery when the ICE is in operation. The battery initially provides the required electrical power to operate an electrical motor that is used to turn the ICE during the starting operation and the ignition system. The most common batteries in use today are flooded lead-acid, sealed gel lead-acid, Nickel-Cadmium (Ni-Cad), Nickel Metal Hydride (NiMH), and Nickel-Zinc (Ni-Z). References on the subject of electrolchemical batteries include the following: Guardian, Inc., "Product Specification": Feb. 2, 2001; K. A. Nishimura, "NiCd Battery", Science Electronics FAQ V1.00: Nov. 20, 1996; Ovonics, Inc., "Product Data Sheet": no date; Evercel, Inc., "Battery Data Sheet--Model 100": no date; S. R. Ovshinsky et al., "Ovonics NiMH Batteries: The Enabling Technology for Heavy-Duty Electrical and Hybrid Electric Vehicles", Ovonics publication 2000-01-3108: Nov. 5, 1999; B. Dickinson et al., "Issues and Benefits with Fast Charging Industrial Batteries", AeroVeronment, Inc. article: no date.
Each specific type of battery has characteristics, which make it either more or less desirable to use in a specific application. Cost is always a major factor and the NiMH battery tops the list in price with the flooded lead-acid battery being the most inexpensive. Evercel manufactures the Ni-Z battery and by a patented process, with the claim to have the highest power-per-pound ratio of any battery. See Table 1 below for comparisons among the various batteries. What is lost in the cost translation is the fact that NiMH batteries yield nearly twice the performance (energy density per weight of the battery) than do conventional lead-acid batteries. A major drawback to the NiMH battery is the very high self-discharge rate of approximately 5 to 10% per day. This would make the battery useless in a few weeks. The Ni-Cad battery as does the lead-acid battery also has self-discharge but it is in the range of about 1% per day and both contain hazardous materials such as acid or highly toxic cadmium. The Ni-Z and the NiMH batteries contain potassium hydroxide and this electrolyte in moderate and high concentrations is very caustic and will cause severe burns to tissue and corrosion to many metals such as beryllium, magnesium, aluminum, zinc, and tin.
Another factor that must be considered when making a battery comparison is the recharge time. Lead-acid batteries require a very long recharge period, as long as 6 to 8 hours. Lead-acid batteries, because of their chemical makeup, cannot sustain high current or voltage continuously during charging. The lead plates within the battery heat rapidly and cool very slowly. Too much heat results in a condition known as "gassing" where hydrogen and oxygen gases are released from the battery's vent cap. Over time, gassing reduces the effectiveness of the battery and also increases the need for battery maintenance, i.e., requiring periodic deionized or distilled water addition. Batteries such as Ni-Cad and NiMH are not as susceptible to heat and can be recharged in less time, allowing for high current or voltage changes which can bring the battery from a 20% state of charge to an 80% state of charge in as quick as 20 minutes. The time to fully recharge these batteries can take longer than an hour. Common to all present day batteries is a finite life and if they are fully discharged and recharged on a regular basis their life is reduced considerably.
SUMMARY OF THE INVENTION
In accordance with the illustrated preferred embodiment, the present invention provides a unique electrical-energy-storage unit that has the capability to store ultrahigh amounts of energy.
One aspect of the present invention is that the materials used to produce the energy-storage unit, EESU, are not explosive, corrosive, or hazardous. The basis material, a high-permittivity calcined composition-modified barium titanate powder is an inert powder and is described in the following references: S. A. Bruno, D. K. Swanson, and I. Burn, J. Am Ceram. Soc. 76, 1233 (1993); P. Hansen, U.S. Pat. No. 6,078,494, issued Jun. 20, 2000. The most cost-effective metal that can be used for the conduction paths is nickel. Nickel as a metal is not hazardous and only becomes a problem if it is in solution such as in deposition of electroless nickel. None of the EESU materials will explode when being recharged or impacted. Thus the EESU is a safe product when used in electric vehicles, buses, bicycles, tractors, or any device that is used for transportation or to perform work. It could also be used for storing electrical power generated from solar voltaic cells or other alternative sources for residential, commercial, or industrial applications. The EESU will also allow power averaging of power plants utilizing SPVC or wind technology and will have the capability to provide this function by storing sufficient electrical energy so that when the sun is not shinning or the wind is not blowing they can meet the energy requirements of residential, commercial, and industrial sites.
Another aspect of the present invention is that the EESU initial specifications will not degrade due to being fully discharged or recharged. Deep cycling the EESU through the life of any commercial product that may use it will not cause the EESU specifications to be degraded. The EESU can also be rapidly charged without damaging the material or reducing its life. The cycle time to fully charge a 52 kWh EESU would be in the range of 4 to 6 minutes with sufficient cooling of the power cables and connections. This and the ability of a bank of EESUs to store sufficient energy to supply 400 electric vehicles or more with a single charge will allow electrical energy stations that have the same features as the present day gasoline stations for the ICE cars. The bank of EESUs will store the energy being delivered to it from the present day utility power grid during the night when demand is low and then deliver the energy when the demand hits a peak. The EESU energy bank will be charging during the peak times but at a rate that is sufficient to provide a full charge of the bank over a 24-hour period or less. This method of electrical power averaging would reduce the number of power generating stations required and the charging energy could also come from alternative sources. These electrical-energy-delivery stations will not have the hazards of the explosive gasoline.
Yet another aspect of the present invention is that the coating of aluminum oxide and calcium magnesium aluminosilicate glass on calcined composition-modified barium titanate powder provides many enhancement features and manufacturing capabilities to the basis material. These coating materials have exceptional high voltage breakdown and when coated onto the above material will increase the breakdown voltage of ceramics comprised of the coated particles from 3.times.10.sup.6 V/cm of the uncoated basis material to around 5.times.10.sup.6 V/cm or higher. The following reference indicates the dielectirc breakdown strength in V/cm of such materials: J. Kuwata et al., "Electrical Properties of Perovskite-Type Oxide Thin-Films Prepared by RF Sputtering", Jpn. J. Appl. Phys., Part 1, 1985, 24(Suppl. 24-2, Proc. Int. Meet. Ferroelectr., 6.sup.th), 413-15. This very high voltage breakdown assists in allowing the ceramic EESU to store a large amount of energy due to the following: Stored energy E=CV.sup.2/2, Formula 1, as indicated in F. Sears et al., "Capacitance-Properties of Dielectrics", University Physics, Addison-Wesley Publishing Company, Inc.: Dec. 1957: pp 468-486, where C is the capacitance, V is the voltage across the EESU terminals, and E is the stored energy. This indicates that the energy of the EESU increases with the square of the voltage. FIG. 1 indicates that a double array of 2230 energy storage components 9 in a parallel configuration that contain the calcined composition-modified barium titanate powder. Fully densified ceramic components of this powder coated with 100 .ANG. of aluminum oxide as the first coating 8 and a 100 .ANG. of calcium magnesium aluminosilicate glass as the second coating 8 can be safely charged to 3500 V. The number of components used in the double array depends on the electrical energy storage requirements of the application. The components used in the array can vary from 2 to 10,000 or more. The total capacitance of this particular array 9 is 31 F which will allow 52,220 Wh of energy to be stored as derived by Formula 1.
These coatings also assist in significantly lowering the leakage and aging of ceramic components comprised of the calcined composition-modified barium titanate powder to a point where they will not effect the performance of the EESU. In fact, the discharge rate of the ceramic EESU will be lower than 0.1% per 30 days which is approximately an order of magnitude lower than the best electrochemical battery.
A significant advantage of the present invention is that the calcium magnesium aluminosilicate glass coating assists in lowering the sintering and hot-isostatic-pressing temperatures to 800.degree. C. This lower temperature eliminates the need to use expensive platinum, palladium, or palladium-silver alloy as the terminal metal. In fact, this temperature is in a safe range that allows nickel to be used, providing a major cost saving in material expense and also power usage during the hot-isostatic-pressing process. Also, since the glass becomes easily deformable and flowable at these temperatures it will assist in removing the voids from the EESU material during the hot-isostatic-pressing process. The manufacturer of such systems is Flow Autoclave Systems, Inc. For this product to be successful it is mandatory that all voids be removed to assist in ensuring that the high voltage breakdown can be obtained. Also, the method described in this patent of coating the calcium magnesium aluminosilicate glass ensures that the hot-isostatic-pressed double-coated composition-modified barium titanate high-relative-permittivity layer is uniform and homogeneous.
Yet another aspect of the present invention is that each component of the EESU is produced by screen-printing multiple layers of nickel electrodes with screening ink from nickel powder. Interleaved between nickel electrodes are dielectric layers with screening ink from calcined double-coated high-permittivity calcined composition-modified barium titanate powder. A unique independent dual screen-printing and layer-drying system is used for this procedure. Each screening ink contains appropriate plastic resins, surfactants, lubricants, and solvents, resulting in a proper rheology for screen printing. The number of these layers can vary depending on the electrical energy storage requirements. Each layer is dried before the next layer is screen printed. Each nickel electrode layer 12 is alternately preferentially aligned to each of two opposite sides of the component automatically during this process as indicated in FIG. 2. These layers are screen printed on top of one another in a continuous manner. When the specified number of layers is achieved, the component layers are then baked to obtain by further drying sufficient handling strength of the green plastic body. Then the array is cut into individual components to the specified sizes.
Alternatively, the dielectric powder is prepared by blending with plastic binders, surfactants, lubricants, and solvents to obtain a slurry with the proper rheology for tape casting. In tape casting, the powder-binder mixture is extruded by pressure through a narrow slit of appropriate aperture height for the thickness desired of the green plastic ceramic layer onto a moving plastic-tape carrier, known as a doctor-blade web coater. After drying to develop sufficient handling strength of the green plastic ceramic layer this layer is peeled away from the plastic-tape carrier. The green plastic ceramic layer is cut into sheets to fit the screen-printing frame in which the electrode pattern is applied with nickel ink. After drying of the electrode pattern, the sheets are stacked and then pressed together to assure a well-bonded lamination. The laminate is then cut into components of the desired shape and size.
The components are treated for the binder-burnout and sintering steps. The furnace temperature is slowly ramped up to 350.degree. C. and held for a specified length of time. This heating is accomplished over a period of several hours so as to avoid any cracking and delamination of the body. Then the temperature is ramped up to 850.degree. C. and held for a specified length of time. After this process is completed the components are then properly prepared for the hot isostatic pressing at 700.degree. C. and the specified pressure. This process will eliminate voids. After this process the components are then side lapped on the connection side to expose the preferentially aligned nickel electrodes 12. Then these sides are dipped into ink from nickel powder that has been prepared to have the desired rheology. Then side conductors of nickel 14 are dipped into the same ink and then are clamped onto each side of the components 15 that have been dipped into the nickel powder ink. The components are then fired at 800.degree. C. for 20 minutes to bond the nickel bars to the components as indicated in FIG. 3. The components are then assembled into a first-level array, FIG. 3, with the use of the proper tooling and solder-bump technology. Then the first-level arrays are assembled into a second-level array, FIG. 4, by stacking the first array layers on top of one another in a preferential mode. Then nickel bars 18 are attached on each side of the second array as indicated in FIG. 4. Then the EESU is packaged into its final assembly.
The features of this patent indicate that the ceramic EESU, as indicated in Table 1, outperforms the electrochemical battery in every parameter. This technology will provide mission-critical capability to many sections of the energy-storage industry.
This EESU will have the potential to revolutionize the electric vehicle (EV) industry, the storage and use of electrical energy generated from alternative sources with the present utility grid system as a backup source for residential, commercial, and industrial sites, and the electric energy point of sales to EVs. The EESU will replace the electrochemical battery in any of the applications that are associated with the above business areas or in any business area where its features are required.
The features and advantages described in the specifications are not all inclusive, and particularly, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the description, specification and claims hereof. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter, resort to the claims being necessary to determine such inventive subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 indicates a schematic of 2320 energy storage components 9 hooked up in parallel with a total capacitance of 31 farads. The maximum charge voltage 8 of 3500 V is indicated with the cathode end of the energy storage components 9 hooked to system ground 10.
FIG. 2 is a cross-section side view of the electrical-energy-storage unit component. This figure indicates the alternating layers of nickel electrode layers 12 and high-permittivity composition-modified barium titanate dielectric layers 11. This figure also indicate the preferentially aligning concept of the nickel electrode layers 12 so that each storage layer can be hooked up in parallel.
FIG. 3 is side view of a single-layer array indicating the attachment of individual components 15 with the nickel side bars 14 attached to two preferentially aligned copper conducting sheets 13.
FIG. 4 is a side view of a double-layer array with copper array connecting nickel bars 16 attaching the two arrays via the edges of the preferentially aligned copper conductor sheets 13. This figure indicates the method of attaching the components in a multilayer array to provide the required energy storage.
CNN : http://money.cnn.com/2006/09/15/technology/disruptors_eestor.biz2/index.htm ; Sept. 20, 2006
"A ceramic power source for electric cars that could blow away the combustion engine."
EEStor's new automotive power source could eliminate the need for the combustion engine - and for oil.
Forget hybrids and hydrogen-powered vehicles. EEStor, a stealth company in Cedar Park, Texas, is working on an "energy storage" device that could finally give the internal combustion engine a run for its money -- and begin saving us from our oil addiction. "To call it a battery discredits it," says Ian Clifford, the CEO of Toronto-based electric car company Feel Good Cars, which plans to incorporate EEStor's technology in vehicles by 2008.
http://www.feelgoodcars.com/index.html
EEStor's device is not technically a battery because no chemicals are involved. In fact, it contains no hazardous materials whatsoever. Yet it acts like a battery in that it stores electricity.
The cost of the engine itself depends on how much energy it can store; an EEStor-powered engine with a range roughly equivalent to that of a gasoline-powered car would cost about $5,200. That's a slight premium over the cost of the gas engine and the other parts the device would replace -- the gas tank, exhaust system, and drivetrain. But getting rid of the need to buy gas should more than make up for the extra cost of an EEStor-powered car.
EEStor is tight-lipped about its device and how it manages to pack such a punch. According to a patent issued in April, the device is made of a ceramic powder coated with aluminum oxide and glass. A bank of these ceramic batteries could be used at "electrical energy stations" where people on the road could charge up.
EEStor is backed by VC firm Kleiner Perkins Caufield & Byers, and the company's founders are engineers Richard Weir and Carl Nelson. CEO Weir, a former IBM-er, won't comment, but his son, Tom, an EEStor VP, acknowledges, "That is pretty much why we are here today, to compete with the internal combustion engine." He also hints that his engine technology is not just for the small passenger vehicles that Clifford is aiming at, but could easily replace the 300-horsepower brutes in today's SUVs.
http://www.businessweek.com/the_thread/dealflow/archives/2005/09/kleiner_perkins_1.html
Kleiner Perkins' Latest Energy Investment, BusinessWeek online, Sept., 3, 2005
Menlo Park, Calif. VC firm Kleiner Perkins Caufield & Byers in July led a $3 million preferred stock investment in EEStor Inc., a Cedar Park, Texas startup that is developing breakthrough battery technology. The company was founded in 2001 by Richard D. Weir, Carl Nelson, and Richard S. Weir, who have backgrounds as senior managers in disk-storage technology at such companies as IBM and Xerox PARC. They previously co-founded disk-storage startup Tulip Memory Systems, where they won 16 U.S. patents. According to a May, 2004 edition of Utility Federal Technology Opportunities, an obscure trade newsletter, EEStor claims to make a battery at half the cost per kilowatt-hour and one-tenth the weight of lead-acid batteries.
http://www.technologyreview.com/Biztech/18086/
Monday, January 22, 2007
Battery Breakthrough?
A Texas company says it can make a new ultracapacitor power system to replace the electrochemical batteries in everything from cars to laptops.
by
Tyler Hamilton
The ZENN car will be the first commercial application of EEStor's new energy storage system. The company is expecting delivery of the systems later this year.
A secretive Texas startup developing what some are calling a "game changing" energy-storage technology broke its silence this week. It announced that it has reached two production milestones and is on track to ship systems this year for use in electric vehicles.
EEStor's ambitious goal, according to patent documents, is to "replace the electrochemical battery" in almost every application, from hybrid-electric and pure-electric vehicles to laptop computers to utility-scale electricity storage.
The company boldly claims that its system, a kind of battery-ultracapacitor hybrid based on barium-titanate powders, will dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety. Pound for pound, it will also pack 10 times the punch of lead-acid batteries at half the cost and without the need for toxic materials or chemicals, according to the company.
The implications are enormous and, for many, unbelievable. Such a breakthrough has the potential to radically transform a transportation sector already flirting with an electric renaissance, improve the performance of intermittent energy sources such as wind and sun, and increase the efficiency and stability of power grids--all while fulfilling an oil-addicted America's quest for energy security.
The breakthrough could also pose a threat to next-generation lithium-ion makers such as Watertown, MA-based A123Systems, which is working on a plug-in hybrid storage system for General Motors, and Reno, NV-based Altair Nanotechnologies, a supplier to all-electric vehicle maker Phoenix Motorcars.
"I get a little skeptical when somebody thinks they've got a silver bullet for every application, because that's just not consistent with reality," says Andrew Burke, an expert on energy systems for transportation at University of California at Davis.
That said, Burke hopes to be proved wrong. "If [the] technology turns out to be better than I think, that doesn't make me sad: it makes me happy."
Richard Weir, EEStor's cofounder and chief executive, says he would prefer to keep a low profile and let the results of his company's innovation speak for themselves. "We're well on our way to doing everything we said," Weir told Technology Review in a rare interview. He has also worked as an electrical engineer at computing giant IBM and at Michigan-based automotive-systems leader TRW.
Much like capacitors, ultracapacitors store energy in an electrical field between two closely spaced conductors, or plates. When voltage is applied, an electric charge builds up on each plate.
Ultracapacitors have many advantages over traditional electrochemical batteries. Unlike batteries, "ultracaps" can completely absorb and release a charge at high rates and in a virtually endless cycle with little degradation.
Where they're weak, however, is with energy storage. Compared with lithium-ion batteries, high-end ultracapacitors on the market today store 25 times less energy per pound.
This is why ultracapacitors, with their ability to release quick jolts of electricity and to absorb this energy just as fast, are ideal today as a complement to batteries or fuel cells in electric-drive vehicles. The power burst that ultracaps provide can assist with stop-start acceleration, and the energy is more efficiently recaptured through regenerative braking--an area in which ultracap maker Maxwell Technologies has seen significant results.
On the other hand, EEStor's system--called an Electrical Energy Storage Unit, or EESU--is based on an ultracapacitor architecture that appears to escape the traditional limitations of such devices. The company has developed a ceramic ultracapacitor with a barium-titanate dielectric, or insulator, that can achieve an exceptionally high specific energy--that is, the amount of energy in a given unit of mass.
For example, the company's system claims a specific energy of about 280 watt hours per kilogram, compared with around 120 watt hours per kilogram for lithium-ion and 32 watt hours per kilogram for lead-acid gel batteries. This leads to new possibilities for electric vehicles and other applications, including for the military.
"It's really tuned to the electronics we attach to it," explains Weir. "We can go all the way down from pacemakers to locomotives and direct-energy weapons."
The trick is to modify the composition of the barium-titanate powders to allow for a thousandfold increase in ultracapacitor voltage--in the range of 1,200 to 3,500 volts, and possibly much higher.
EEStor claims that, using an automated production line and existing power electronics, it will initially build a 15-kilowatt-hour energy-storage system for a small electric car weighing less than 100 pounds, and with a 200-mile driving range. The vehicle, the company says, will be able to recharge in less than 10 minutes.
The company announced this week that this year it plans to begin shipping such a product to Toronto-based ZENN Motor, a maker of low-speed electric vehicles that has an exclusive license to use the EESU for small- and medium-size electric vehicles.
By some estimates, it would only require $9 worth of electricity for an EESU-powered vehicle to travel 500 miles, versus $60 worth of gasoline for a combustion-engine car.
"My understanding is that the leap from powder to product isn't the big leap," says Ian Clifford, CEO of ZENN, which is also an early investor in EEStor. "We're the first application, and that's thrilling for us. We took the initial risk because we believed in what they are doing. And energy storage is the game changer."
The key challenge, however, is to ensure that the barium-titanate powders can be made on a production line without compromising purity and stability. "Purification gives you better production stability, gives you better permittivity, and gives you the high voltages you're looking for," says Weir. "We've now got the chemicals certified and purified to the point we're looking for." (Better permittivity of the insulator improves the amount of charge that can be stored without letting the current leak across the two plates.)
EEStor announced this week that the first automated production line for its powder has performed as required and that permittivity will meet or exceed expectations. It also said that it achieved 99.9994 percent purity for its barium-nitrate powder, a crucial ingredient in the dialectric. San Antonia-based Southwest Research Institute independently confirmed the results.
In a traditional ultracap, that permittivity is given a rating of 20 to 30, while EEStor's claim is 18,500 or more--a phenomenal number by most accounts. "This is a very big step for us," says Weir. "This puts me well onto the road of meeting high-volume production."
Jim Miller, vice president of advanced transportation technologies at Maxwell Technologies and an ultracap expert who spent 18 years doing engineering work at Ford Motor, isn't so convinced.
"We're skeptical, number one, because of leakage," says Miller, explaining that high-voltage ultracaps have a tendency to self-discharge quickly. "Meaning, if you leave it parked overnight it will discharge, and you'll have to charge it back up in the morning."
He also doesn't believe that the ceramic structure--brittle by nature--will be able to handle thermal stresses that are bound to cause microfractures and, ultimately, failure. Finally, EEStor claims that its system works to specification in temperatures as low as -20 °C, revised from a previous claim of -40 °C.
"Temperature of -20 degrees C is not good enough for automotive," says Miller. "You need -40 degrees." By comparison, Altair and A123Systems claim that their lithium-ion cells can operate at -30 °C.
Burke, meanwhile, says that there's a big difference between making powder in a controlled environment and making defect-free devices in a large quantity that can survive underneath the hood of a car.
"I have no doubt you can develop that kind of [ceramic] material, and the mechanism that gives you the energy storage is clear, but the first question is whether it's truly applicable to vehicle applications," Burke says, pointing out that the technology seems more appropriate for utility-scale storage and military "ray guns," for which high voltage is an advantage.
Safety is another concern. What happens if a vehicle packed with a 3,500-volt energy system crashes?
Weir says the voltage will be stepped down with a bi-directional converter, and the whole system will be secured in a grounded metal box. It won't have a problem getting an Underwriters Laboratories safety certification, he adds. "If you drive a stake through it, we have ways of fusing this thing where all the energy is sitting there but it won't arc … It will be the safest battery the world has ever seen."
Regarding concerns about temperature, leakage, and ceramic brittleness, Weir did not reply to an e-mail asking him how EEStor overcomes such issues.
Nonetheless, the company has some solid backing. Its board has attracted Morton Topfer, former vice chairman of Dell and mentor to Michael Dell.
The company is also backed by Kleiner Perkins Caufield & Byers, a venture-capital powerhouse that has an impressive track record: it made early and highly successful bets on Google, Amazon.com, and Sun Microsystems, among others. Whether EEStor can translate that success to the energy sector remains to be seen.
"I'm surprised that Kleiner has put money into it," says Miller.
Weir maintains that his company will meet all of its claims, and then some. "We're not trying to hype this. This is the first time we've ever talked about it. And we will continue to meet all of the production requirements."
