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Li-ion battery tech to make or break Chevy Volt

Posted: 22 May 2009 ?? ?Print Version ?Bookmark and Share

Keywords:GM Chevy Volt? Li-ion battery? electric car?

Even as General Motors teeters on the brink of bankruptcy, engineers at Chevrolet are working on one of the boldest innovations in GM's history: the Chevy Volt.

Unveiled at the Detroit Automotive Show in 2007, the Volt project has become GM's most ambitious effort: a range-extended electric vehicle powered by a revolutionary battery platform called the Voltec. The pet project of VP of global development Bob Lutz, the Volt is GM's "Hail Mary"!the one innovation deemed capable of pulling the company back from the precipice. Lutz has known from the start, however, that if the car is to succeed at its planned launch in November 2010, its battery technology!the heart of the Volt!needs to be the car's greatest innovation, and it had best not skip a beat. If the production battery proves less than perfect, the Volt will be dead on arrival!and GM's fate, analysts have predicted, could likewise be sealed.

Battery rollout at North American International Auto Show

Ten-year, 4,000-cycle challenge
Developing a reliable, cost-effective battery would thus be one of the largest technical hurdles facing the Volt project team. GM believed that to achieve an end product that would meet its standards for the Volt's battery, an open competition would be required. The challenge presented to the interested parties was straightforward: Develop a Li-ion battery that could be recharged for 4,000 cycles and would last a minimum of 10 years. Sounds simple enough, until you consider that there was next to nothing on the Li-ion market that could come close to meeting those criteria.

From the initial field of 27 entrants, the competition was narrowed to two prospective partners in June 2007. The two finalists were A123Systems, a Michigan-based company with expertise in Li-ion technology, and a coalition team of LG Chem and Compact Power Inc. Both teams were awarded contracts to develop prototypes in parallel. Considering the critical nature of the battery, GM believed it was necessary to have two organizations engaged in developing the technology at the same time. The reasoning was that with two teams openly competing for the final production contract, the very best battery would be developed!one that would not only meet the car maker's criteria but exceed them. Prototypes were to be developed by January 2008 for GM to test in "mules," or mock-ups of the Volt made with Malibu body cases, with a final decision to follow.

Battery testing at LG Chem

In January 2009, GM selected the design from the team of LG Chem and Compact Power as the one that would best fit the Voltec platform from a structural standpoint. The cells in the LG Chem battery were deemed the most appropriate in structural integrity testing, and the cell size was the best fit with the cooling system that GM had designed for the Volt. The LG Chem battery provided the best results in rear-impact and side-impact crash tests. Most important to GM, which would be footing most of the manufacturing cost, was its confidence in the battery's ease of manufacturability and LG Chem's established track record in Li-ion manufacturing (A123 Systems was essentially a startup). The battery would be manufactured in Michigan in a facility that would be the first Li-ion battery plant in the United States to be operated by a major automaker.

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