By Drew Johnson
Friday, Dec 9th, 2011 @ 10:11 am
 
With the company's plug-in Chevrolet Volt model now the subject of a federal safety investigation, General Motors will switch to a less volatile battery chemistry for its upcoming Chevrolet Spark electric vehicle.

General Motors announced earlier this year that it will use lithium phosphate batteries for its Spark EV rather than the lithium metal oxide technology used in the Chevrolet Volt. The phosphate batteries store less energy and require more space than their metal oxide counterparts, but the technology is much more stable.

"Lithium phosphate chemistry looks like it could be more friendly in terms of heat management," said James Hall, principal of consulting company 2953 Analytics Inc. "But it stores less energy. There is a tremendous amount of new discovery. This is new territory for lithium batteries." Lithium phosphate technology wasn't readily available during the Volt's development.

However, GM is willing to accept those tradeoffs as the Volt's lithium metal oxide batteries are now the subject of a NHTSA probe. That investigation was launched after a Volt caught fire three weeks after it was crash tested by the safety agency.

Lithium phosphate batteries are not fire proof, but it's more difficult for a fire to spread between cells.

A123 Systems will produce the lithium phosphate batteries for the Spark EV, which is slated to hit showrooms in 2013.

References
1.'GM Buys Batteries...' view