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.

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.