Are Batteries in Electric Cars Safe? - BusinessWeek

Next month will mark another important milestone on the road to cleaner, greener motoring: Mitsubishi Motor (7211.T) will begin mass-producing an electric vehicle, becoming the first major carmaker in the world to do so. Subaru, a unit of Japan's Fuji Heavy Industries (7270.T), plans to sell 170 of its $48,000 plug-in Stella electric cars this year. China's BYD Auto, which has been selling a plug-in gas-electric hybrid car to businesses since December, aims this year to release an electric vehicle that can go 300km to 400km when charged. In mobile phones, laptops, and other portable gadgets, thermal runaway can occur in 1 of every 5 million to 10 million cells, says Brian Barnett, a battery expert at technology firm Tiax in Cambridge, Mass. A laptop batteries usually has six cells, but electric cars will likely rely on 75 or 80 cells, meaning they would be more susceptible to problems.