Now, G.M. is planning two plug-in hybrid vehicles. Like the Toyota Prius and other available hybrids, the G.M. models will supplement their electric motors with power from internal combustion engines. What’s different is that most of the power for daily commuting will come from battery packs that can be recharged from ordinary household sockets. The new models are expected to have a range of at least 40 miles without using their gas engines. While that is less than the range of the all-electric EV1, the hybrid nature of the new models will give them far greater total range.
G.M. says that the extra cost for the battery packs mean that plug-in hybrids will sell for thousands of dollars more than comparable, non-electric vehicles. But the average driver, going 40 miles a day, would also save $450 a year if gasoline were $2 a gallon. Because the median daily travel of the average American car is 33 miles (well within the new model’s electric range), the cars would achieve 155 miles to the gallon, and many drivers would fill up with gasoline only every few months.
G.M. hopes to begin selling the first car, a plug-in hybrid version of the Saturn Vue sport utility, as soon as 2009. The second, the Chevrolet Volt, which exists only as a concept-model prototype, is a startling departure from traditional automotive design. The Volt’s internal combustion engine is not attached to the drive train as current hybrids are. In the case of the Volt, it is used only to recharge the vehicle’s batteries. In short, the Volt would function as a true electric car, with the insurance of an internal combustion engine — and not coincidentally it is also designed as a recognizably conventional American compact, seating five, which could drive hundreds of miles to Mother’s at Thanksgiving.
“The real breakthrough is with the new batteries, which offered us energy density — which in turn provided us with a reliable, high-powered package in a relatively small space,” Mr. Zelenski said.
G.M. selected A123Systems (along with its partner Cobasys) to develop batteries that might be used for the Saturn Vue, he said, and it is considering awarding A123Systems a similar contract for the Volt concept car, to take advantage of the company’s remarkable new rechargeable lithium batteries.
Rechargeable lithium batteries have been used in laptop computers and mobile phones since the early 1990s. (Their common name, “lithium ion batteries,” is a tautology, since all batteries conduct electric current by allowing the passage of ions between two electrodes.) But despite their lightness, rechargeable lithium batteries — which often use a compound of highly reactive cobalt oxide — have hitherto been thought impractical for transportation because they are insufficiently powerful and might, if pierced, jarred or overheated, explode or burst into flames.
A123Systems batteries are different. Yet-Ming Chiang, a professor of materials science and engineering at M.I.T. and a co-founder of A123Systems, described their advantages: “Used in a hybrid vehicle, our batteries deliver faster acceleration than any other batteries of the same size,” Professor Chiang said. “And the chemical stability of the cathode material greatly improves safety as well as extending battery life.”
