During a media briefing at its Brownstown Township, MI battery plant this afternoon, General Motors Vice Chairman Tom Stephens announced that the lithium ion battery pack for the 2011 Chevrolet Volt would be warranted for eight years or 100,000 miles. Since the beginning of the program, it has been General Motors' intention to develop the battery pack to last for the life of the vehicle.

Despite the fact that the Volt is considered an electric car by GM, the presence of an on-board gas engine for range-extending means that the EPA and California Air Resources Board consider the battery to be part of the car's emissions control system. As a result, it is subject to the same regulations as parts like a catalytic converter, and therefore, it must have the eight-year warranty.

GM has released some additional specifications on the battery pack. In its final production form, 95 percent of the components were designed and developed in-house by GM, it weighs in at 400 pounds and has an output of 110 kilowatts. Internally, the water-cooled pack consists of 288 LG Chem lithium polymer cells. Over the next few months, GM will be ramping up the production rate at Brownstown in preparation for the start of Volt production this Fall.