More on EEstor's ultracapacitor - can we believe the hype?
ZENN Motors vehicle at the EDTA Conference last November
More details have emerged about EEStor's ambitious ultracapacitor electrochemical battery replacement technology. EEStor sees applications for their Electrical Energy Storage Units (EESU) in everything from hybrid-electric and pure-electric vehicles, to laptop computers, to utility-scale electricity storage. Based on barium-titanate powders, the units are supposed to dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety. And since capacitors don't require chemical processes to store power, EEStor said in its patent, the materials the company uses are safer and more environmentally friendly.
Ultracapacitors store energy in an electrical field between two closely spaced conductors, or plates, upon which an electric charge builds when voltage is applied. Unlike traditional electrochemical batteries, ultracapacitors can completely store and release a charge quickly and indefinitely over many cycles. Where they don't compete though is energy storage; here lithium-ion batteries can store 25 times more specific energy - the amount of energy in a given unit of mass.
Most research into increasing the charge that can be stored by the plates has focused on ways to increase the surface area. Last year, the Massachusetts Institute of Technology said it was working on hugely increasing the plate surface area by researching plates made of microscopic nanotubes.
Up until now, ultracapacitors, have been used in conjunction with traditional batteries to more fully harness the regenerative energy created in sudden bursts by braking activity with their ability to release quick jolts of electricity. Their characteristics are ideal for maximising efficiency in stop-start city driving. Ultracapacitor manufacturer Maxwell Technologies has been able to capitalise on this strategy in their 125-volt BoostCap ultracapacitor module.
EEStor's EESU, a ceramic ultracapacitor with a barium-titanate dielectric, or insulator, is claimed to break free of the traditional limitations of small energy storage found in other ultracapacitors. Apparently they have achieved an exceptionally high specific energy and permittivity - the ability of an substance to store electrical energy in an electric field. Normally an ultracapacitor has a permittivity rating of 20 to 30, compared to the claimed EESU rating of 18,500 plus. As you can imagine, such claims have raised questions amongst experts who hold concerns that such ceramic materials can survive and function properly in vehicle applications.
In an interview with Technology Review, Jim Miller, vice president of advanced transportation technologies at Maxwell Technologies said, "We're skeptical, number one, because of leakage. Meaning, if you leave it parked overnight it will discharge, and you'll have to charge it back up in the morning."
In the same article, Andrew Burke, an expert on energy systems for transportation at University of California at Davis said, "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."
ZENN Motor Company is reported to be getting first access to EEStor's EESU technology for use in their Low Speed Vehicles.
Maxwell Technologies meanwhile has just announced that they are forging ahead with their technology and have received a purchase order for 100,000 square meters / 1,076,400 square feet of proprietary ultracapacitor electrode material from a licensee, Shanghai Sanjiu Electric Equipment Co. This will allow Sanjiu Electric to launch a new ultracapacitor product line based on Maxwell's Cell Architecture for transportation, utility and industrial markets in mainland China.
Mr. Hong Yuan Shuai, Chairman and CEO of Sanjiu Electric parent company, the Ruihua Group, said that Sanjiu Electric has already produced and delivered a variety of prototype electric and hybrid buses, trucks and other vehicles powered by drive systems combining batteries and Maxwell BoostCap ultracapacitors for energy storage and regenerative braking.
Analysis: The EESU prospects are exciting, but I think Maxwell's use of ultracapacitors in regenerative breaking applications is probably a better choice for vehicular applications at this point. Where EEStor's products could open up a sizeable lead over the opposition though is in the area of military, direct-energy "ray-gun" weapons. Personally, I'll just stick with better fuel economy in stop-start traffic.
Related:
[Source: Technology Review]
Reader Comments (Page 1 of 1)
Old Runner 11:34PM (6/29/2009)
I be believe the investment in EESTOR batteries is a good one even if it never gets used in an electric automobile there a lot of other uses for less powerful small batteries. It provides diversity! About 20 years ago I was a technician working for PHD's. One professor suggested that a capacitor could replace
car batteries. I thought he was nuts!
I now suspect EESTOR is dreaming of a device that is both capacitor and battery at the same time. If it's capacitance became smaller with a heavy current drain it would dump some current into the load for the seconds when it was needed most.
Since I am just an old man I am probably wrong I hope some one tells me if I guessed right or wrong.
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Mike Langridge 8:22AM (2/01/2007)
This article is unclear. Para 1 says these ultracaps have a higher energy density, para 2 says they dont:
(1) Based on barium-titanate...ESSU...dramatically outperform ..lithium-ion ...in terms of energy density....
(2)
Ultracapacitors ... don't compete though ..(on).. energy storage...lithium-ion batteries can store 25 times more specific energy - the amount of energy in a given unit of mass.
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Truman Ross 1:16PM (10/03/2008)
Coleman has already produced a super capacitor "flash Cell" electric screw-driver that recharges from a "dead" state to full charge in 90 secs. I own one. I have used it many, many times, and the charge rate is still the same. It is powered with Ultra capacitors. I see NO reason why this Tech. can't be used in electric autos!! I would be first in line to purchase one !!
fawgcutter 12:47PM (2/01/2007)
I think the first paragraph is in reference to EEStor's claims. The other is in actual energy retained by the device.
The problem with any EV storage system is how many kilowatt-hours (kW-hrs) it can store, how fast they can be released from storage to supply the motor (for acceleration), and most importantly, how fast can they be put back into storage.
Dane's got a point in comparing EEStor's claims with other industry and academic findings. Electrode surface area is important, as the current delivered by any current electrochemical device is a function of its surface area (witness: the number of plates in a lead-acid battery).
IMO I'll wait til EEStor come up with the goods.
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Tim 3:23PM (2/01/2007)
We’re all chewing our fingernails to the quick waiting for EEstore’s EESU to PROVE they work and are good for automobiles! I really hope they do, and quickly…
Historically, the problem with ultracaps is that they leak which makes them better suited for short-term boost power than long-term storage. Since we are now worried about the availability of lithium (its limited and the US has NONE), perhaps the best way to use ultracaps is in tandem with Zebra batteries. We have lots of salt. http://www.evworld.com/view.cfm?page=article&storyid=1138 A little peanut butter with your chocolate?
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Bob Deverell 1:42AM (2/23/2007)
Was reading that some people a concerned about the current needed to quickly charge an EV. No witchcraft here. While its true existing home utility outlets can only charge at say 3 Kw/hour, requiring all night charging. But EESTOR technology provides a simple solution to those who want to pay for fast charging. All that is required for sub-hour charges is is an external EESTOR type module trickled charged from the public utility then squirted into the EV.
For fuel station or parking meter type refueling, a beefed up set of storage units would solve their peak electric demand problem.
Bob
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BOB FOX 3:25AM (3/19/2007)
My 2000 Honda Hybrid is getting to the end of its battery life. I do hope that I can get a replace-
ment battery from EEStors before i have to buy one from the current market that will also have a limited life.
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Ivor 11:16PM (5/02/2007)
>Posted at 3:25AM on Mar 19th 2007 by BOB FOX
>5. My 2000 Honda Hybrid is getting to the end of its battery life. I do hope that I can get a replacement battery from EEStors before i have to buy one from the current market that will also have a limited life.
Bob... I've been curious if a hybrid battery pack has any use to someone with a home PV system that might want to store some juice for the evenings? Anyone have experience in this area yet?
Ivor
Portland OR
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Tony Maine 2:24AM (5/16/2007)
I am concerned about safety. At this energy density, and with that amount of dielectric stress, what happens if the capacitor is cracked? Even a single microcrack will at 3.5 kV produce an arc (a hundred megavolts per metre will break down any gas, even sulfur hexafluoride at 300 bar) whereupon the battery turns into a plasma, all the energy comes out in a microsecond and you have the equivalent of 100 lb of TNT explosion - end of battery, car, occupants and technology. This is supposed to be the salvation of EVs not some terrorist weapon.
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bob deverell 10:45PM (7/03/2007)
Tony,
Its hard to explain the role of fuses to a scientist, rather than an engineer, but consider that without a circuit there is no power. All materials have finite current handling capacity. This makes it simple to fabricate a completely safe electrical storage device. In fact a high voltage low current approach makes it easier and safer than say a 12v battery.
Bob Bangkok
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john 12:29PM (7/05/2007)
The problem with fuses, Bob, is that they dont know whether the current being demanded is to accelerate the vehicle or from an internal short. By definition they add a resistance to the circuit, so to make this 100 lbs of dynamite safe, you might have to limit the acceleration considerably.
How many people would want to sit on a device that has that power, held back by a million square inches of 13 micron thick dielectric, with 3500 volts across it. (a piece of paper is 75 microns). One defect, one crack, one kick in the wrong place and "boom!" Even if you consider fusing each one of the 1000 element they propose, each one can explode with the power of 0.1 lbs of dynamite, which shorts the next one, and a chain reaction takes place.
And without a circuit there is no CURRENT. Power depend on what the current is doing.
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zrski 9:41PM (7/05/2007)
Yeah, that's much more dangerous than 16 to 20 gal. of a highly volatile liquid.
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john 3:14PM (7/06/2007)
If a fire starts in a standard car, generally you have a chance to escape, the fire/explosion is not instantaneous. Imaging trying to outrun a lighning bolt when you saw it coming.
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bob deverell 2:50AM (7/10/2007)
John, the problem with dis-information is that it catches up with you in the end.
100 lbs dynamite. Get real. I think you know 'all too well' that dynamite does not explode unless contained/compressed, any more than gasoline or any other explosive material. Of course you could ask EESTOR to deliberately spend some extra money and design their store to explode, but somehow I don't think they will bother. (I don't even think the military are that desperate) I also think you know that the acceleration of an EV saloon fused at 15 amp at 3500v (work out the torque) will better most ICE. Only 2 or 3 amps is required from the store for highway cruising speeds. I reckon a 14 year kid can solve that fuse problem.
13 microns at 3500v, where did you get that ?
I think most people would rather trust a storage device that is limited to say 15 amps than a conventional battery capable of supplying hundreds of amps !
Bob Bangkok
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john 12:48PM (7/13/2007)
The ceramic casing acts as a pretty rigid container. I have seen small ceramic capacitor blow up and send little bits of material flying. The eestore device claim is a huge amount of energy. One stick of dynamite is about 1.2 million joules...do the calculation.
And dynamite wont explode if its not contained? Are you serious? Would you stand next to a stick and light it? Would you hold even a firecracker in your open hand?
The problem with the capacitor as it discharges is the voltage goes down as it discharges. If it maintained the 3500 volts, you are right, that is enough to accelerate, but...
The 13 micron dielctric with 3500 volts is what is called out in the patent. That is one of the troublesome things to me.
How will one be able to charge the capacitor in 5 minutes with a 15 amp fuse in the circuit, is the fuse smart enough to know the difference?
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questions 11:19PM (2/13/2008)
Hello, guys
I have a question about ferroelectric materials such as barium titanate which is used for ultracapacitors. If you look at a hysteresis diagram of barium titanate, the material is fully polarized at the highest voltage. However, when the voltage goes back to zero voltage, the polarization still exists. It is called remanant polarization. This means that if we applied current, the ferroelectric release only less than 10% energy that we applied. If there is no remnant polarization at 0 V, what EEstor claimed is absolutely right. Otherwise, their claim may not be right. do I bring stupid issue or question? Please, help me
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