Conference panelists see car battery breakthrough

But although the technology shows great promise, battery makers worldwide still are grappling with high costs, the impact of charging and depletion on battery life, keeping the batteries cool and other issues, according to panelists at the Plug-In 2008 conference in San Jose.

Tien Duong, who works in emerging battery technology with the U.S. Department of Energy, told the group he believes lithium-ion batteries are ready to start displacing the nickel-metal-hydride batteries now used in many hybrid gas-electric vehicles.

Hybrids are powered by electric and internal combustion engines, while plug-ins operate exclusively on electricity. They can be charged by plugging them into a conventional home outlet, but they also carry a small conventional motor to recharge the batteries and extend their range. Plug-ins generally can get up to 100 miles per gallon of gasoline.

Panelists said lithium-ion batteries are better suited for plug-ins because they have more storage capacity, cost less and are smaller and more reliable than nickel-metal-hydride powerpacks.

Lithium-ion shows promise in giving cars a range of 40 miles per charge, said Haresh Kamath, energy storage project manager for the Electric Power Research Institute, one of the conference sponsors.

"The target is 40 miles, and we don't think we can do that with nickel-metal-hydride," he said in an interview. "Lithium-ion, it's a lot more likely to get there."

Still, the lithium-ion battery packs needed to power even a small car now cost in excess of $10,000, said Kamath.

Duong said battery costs will have to be cut by at least half to make the cars cost-effective, but Fritz Kalhammer, an independent consultant in energy technology, said there's reason for optimism on the cost side because of high gasoline prices.

"The batteries cost less than the fuel cost savings they enable," he said.