Rechargeable lithium batteries have been used in laptop computers and mobile phones since the early 1990s. (Their common name, â€œlithium ion batteries,â€ 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 â€” which often use a compound of highly reactive cobalt oxide â€” 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: â€œUsed in a hybrid vehicle, our batteries deliver faster acceleration than any other batteries of the same size,â€ Professor Chiang said. â€œAnd the chemical stability of the cathode material greatly improves safety as well as extending battery life.â€