IMAGE: VOLVO CAR THAT RUNS ON LITHIUM BATTERIES
Rick Dole  /  Copyright 2004 Michelin North America, Inc.
Volvo's 3CC concept car is powered solely by rechargeable lithium-ion batteries.
updated 2/16/2006 2:15:39 PM ET 2006-02-16T19:15:39

Sandia National Laboratories is trying to build a better battery for the hybrid vehicles of today and the fuel-cell vehicles of the future.

Researchers are working on a lithium-ion battery, which holds the promise to cost less and perform better than the nickel-metal hydride batteries hybrids now use, said Dan Doughty, manager of Sandia's advanced power sources research and development department.

Lithium-ion batteries aren't new technology. They're used in cell phones and music devices like Ipods. And they've become the power source for many laptop computers because they perform better than previous computer batteries.

But automotive technology is more complex.

Lithium-ion batteries would have to be cheaper than nickel-metal hydride, last as long and weigh less, "which is a very hard problem," said Doughty, who has worked in the power sources group for 13 years. A battery also must be abuse-tolerant — meaning if it fails, it won't cause other problems.

If those issues can be solved, "the manufacturing base would grab this and run," Doughty said.

FreedomCAR funding
Sandia receives $1.5 million a year from the Department of Energy's FreedomCAR program for the lithium-ion research.

FreedomCAR is aimed at developing electric-powered vehicles to help free the United States from dependence on foreign oil. Sandia and four other national labs — Argonne, Lawrence Berkeley, Idaho and Brookhaven — are working on different aspects of developing hybrid technology.

The demand for more fuel-efficient vehicles has risen with gasoline prices, adding to the pressure for more hybrid and fuel-cell electric vehicles.

In that respect, "high gas prices are a good thing because it helps people think about their use of the natural resources, and they see the cost more clearly," Doughty said.

Hybrids aren't as clean as fuel-cell vehicles, but they deliver better mileage than comparable gas engines by switching between an electric motor and gasoline engine. The U.S. hybrid market increased by more than 140 percent in the past year — but hybrids also cost about $3,500 more on average.

The lithium-ion battery is widely considered to be the next generation of battery technology, said Jason Mark of Berkeley, Calif., vehicles director with the Union of Concerned Scientists.

Ready by 2010?
Researchers have been improving the lithium-ion battery for a decade. What's needed now is testing and analysis to validate the battery's life and performance in hybrids, as well as its real cost, said Ted J. Miller, who works on advanced battery technology for the Ford Motor Co.

Miller, speaking on behalf of the U.S. Advanced Battery Consortium, which has worked closely with Sandia on a lithium-ion battery, said he expects the technology to be introduced in hybrids before the end of the decade.

Lithium-ion batteries are able to deliver more energy, "but my sense is that one of the real challenges of lithium-ion batteries has been cost," Mark said.

The other is durability.

"The battery has to last 150,000 miles, which is the life of a car. That is no small feat," Mark said. "Durability becomes a cost issue if you have to change your several-thousand-dollar battery twice in the life of the car. That significantly changes the economics of a hybrid vehicle."

Doughty agrees battery life and cost are linked. If a battery is cheap enough, it could be replaced more frequently; if it lasts a long time, a customer might be willing to spend more money for it, he said.

Aim for 15-year lifespan
The Advanced Battery Consortium, in published requirements for hybrid batteries, wants them to last a challenging 15 years, Doughty said. Current nickel-metal hydride batteries in a Toyota Prius, by comparison, are warranted for eight years or 100,000 miles.

One problem with lithium-ion batteries has been durability. Sandia's abuse tolerance testing is aimed at seeing how they function outside a normal operating range. And if something fails, researchers want it to fail gracefully — without damaging other systems.

"We haven't solved the problems yet," Doughty said.

Engineers also want systems that have a wide margin of error before failing.

"You won't want them to fail if you're driving just a little too fast, so we take batteries to conditions they're not designed for and see how they fail," Doughty said.

Researchers overheat the batteries, simulate a fuel fire, crush or penetrate batteries and drop them on hard surfaces. They also charge them too much, perhaps to twice the limit, or short-circuit them.

"The idea is to see what the response of it is, to characterize the magnitude of the response, how severe it is" so engineers can figure out how to overcome the problem, Doughty said.

Copyright 2006 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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