Batteries that pack a punch without a pop

A Texas company devises a lithium ion battery for cars that is designed to avoid explosive mishaps.

Michael Kanellos Staff Writer, CNET News.com
Michael Kanellos is editor at large at CNET News.com, where he covers hardware, research and development, start-ups and the tech industry overseas.
Michael Kanellos
2 min read
Except for the rare moments when they burst into flames, lithium ion batteries have helped revolutionize electronics.

Valence Technology, a small company in Austin, Texas, says it has come up with a way to throttle the explosive properties of the battery technology and make larger lithium batteries that can power tools or even hybrid cars. To date, lithium ion batteries have mostly been used in notebooks and personal electronics.

Batteries are big business these days in Silicon Valley. Tesla Motors recently unveiled an all-electric sports car that in part is possible by improvements the company made to the lithium ion battery pack that powers the car.

Venture capitalists are also plunking money into companies like PowerGenix, which makes a nickel zinc battery. Zinc batteries have been around since Edison, according to CEO Dan Squiller, but have not been exploited fully. PowerGenix will sell batteries for large items that need hefty bursts of power, like power tools.

Valence has tamed some of the explosive properties of its U-Charge Power System lithium ion batteries by changing the cathode material, the metallic pole inside a battery that attracts electrons. Most lithium ion batteries have a cobalt oxide cathode. By contrast, Valence employs one made of metal phosphate.

Batteries with the metal phosphate can store only about 75 percent of the energy a traditional lithium ion battery can hold. However, the phosphate won't burn. In traditional lithium ion batteries, heat inside the battery can cause the cobalt oxide cathode to decompose.

"Then you have lots of explosions and smoke and gas," said Dean Bogues, president of worldwide sales and marketing. "We eliminate the risk of a runaway thermal reaction."

The company sells its batteries to those who want to convert their hybrid cars into plug-in hybrids, which run almost exclusively on electricity. These cars can get 100 miles per gallon or more, and emit far fewer fumes from the tailpipe. (Fumes are created at the electrical power plant, but in general, the greenhouse gas output is less than with a standard car.

"We've integrated them into wheelchairs, fleet scooters, hybrids, marine applications," Bogues said. The U-Charge batteries also weigh less than traditional lead acid batteries.

Eventually, the technology could make its way to notebooks. "At some point, some company will push for safer batteries," he said.

Valence has already completed and started selling its batteries, but the target customers in the vehicle market tend to move slowly, so it could be a while before you see a lot of them. Some European companies, though, are tinkering with them in their delivery fleets.