January 17, 2006 12:37 PM PST
Better batteries for hybrid cars?
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As part of the Department of Energy's FreedomCAR program, the laboratory is trying to figure out how to get the battery technology--which provides better power than conventional batteries but presents safety issues--inside hybrid car engines.
Lithium ion batteries have two to three times the energy density of nickel-cadmium and nickel-metal hydride batteries (hybrids use nickel-metal hydride batteries) and four times the energy density of lead-acid batteries. Higher energy-density would translate to longer battery life, leading to better gas mileage on hybrid cars.
Lithium ion batteries for hybrids might also cost less, according to Sandia. The catch is that the chemical reactions, which allow these batteries to produce electricity, are somewhat violent, and battery flaw or failure can result in extensive damage.
In cell phones, lithium ion batteries can overheat because of a short circuit. If the temperature rises too slowly, the battery case may melt. If it rises too rapidly, however, enough pressure may be generated to create a small explosion in a lithium ion battery. Consumers have suffered severe burns as a result of these failures.
Sandia's research will largely revolve around how well various experimental lithium ion batteries endure nearby heat- and gas-generating reactions and other abuses found in cars. Ideally, the battery will be able to withstand the environmental factors and degrade harmlessly if damaged.
"Current hybrid vehicles use nickel-metal hydride batteries, but a safe lithium ion battery will be a much better option for the hybrids," Dan Doughty, manager of Sandia's Advanced Power Sources Research and Development, said in a statement. "Fixing the problem will come from informed choices on improved cell materials, additives and cell design, as well as good engineering practices."
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