Li-ion Not Ready for Prius

The Wall Street Journal reports that Toyota has decided against the use of lithium-ion battery technology - at least initially - in the next-generation Toyota Prius, which is still expected in fall 2008.

The company will instead, at launch, use a new version of the company's existing nickel metal hydride battery pack in the new Prius, an inside source told the WSJ.

The battery system that Toyota had been considering, which was to be supplied by Panasonic EV Energy Co., would have enabled significant packaging benefits for the next Prius, as lithium-ion batteries allow an equivalent energy capacity to be stored in a smaller, lighter package. The only downsides for this relatively new technology, which is already commonplace in laptops and some personal electronics, are initial cost, which has been coming down considerably, and the safety and reliability concerns associated with the tendency of these batteries to run hot. 

Hybrid experts have been anticipating substantially improved mileage in the upcoming Prius, due to the lithium-ion system's reduced weight, increased battery capacity, or a combination of the two benefits.

The WSJ mentioned that this delay might give General Motors a boost, as it has been aiming to get its Saturn Vue Green Line plug-in hybrid - which will sport lithium-ion batteries - to market by fall of 2009. If its launch can stay as scheduled, it now may be the first lithium-ion vehicle from a major automaker.

Company president Katsuaki Watanabe has recently been emphasizing the company's need to maintain its product quality. Recent product woes in the U.S. include a highly publicized engine-failure issue that may affect up to 30,000 new V-8 Tundra pickups.

A Toyota Motor Sales USA communications officer would not comment on the Prius decision, but said, "Our research and development, including that for Prius, is broad-reaching and being carried out from various angles."