Blog from the 2011 SAE International Batteries and E-Motors Summit
SHANGHAI, CHINA—Tuesday afternoon, Nov. 15, 2011—One of the auto industry’s most respected battery experts is cautiously optimistic that a Chevrolet Volt battery fire that occurred weeks after a government crash test won’t affect the public’s attitude toward EVs.
“The Chevy Volt fires are probably not a major issue; they’re most likely an isolated occurrence,” said Dr. Menahem Anderman, President of the Advanced Automotive Batteries consultancy. Dr. Anderman is Session Chair of the 2011 SAE Vehicle Battery Summit being held here this week.
A Volt caught fire while parked at a U.S. National Highway Traffic Safety Administration testing center in Wisconsin, three weeks after a side-impact crash test had punctured its traction-system battery pack. General Motors is working cooperatively with NHTSA in its investigation of the fire. Company engineers and technicians have put in almost 300,000 h testing the extended-range electric vehicle and its sophisticated lithium-ion battery pack system, including numerous dual-level failure-mode tests.
Li-ion batteries could potentially catch fire if the battery case and some of the internal cells that store electricity are pierced by steel or another ferrous metal, battery experts here told AEI. If a Li-ion battery is pierced by steel, a chemical reaction will take place that starts a temperature rise that can precipitate a fire. If the piercing is small, that reaction can take days or weeks.
Deactivating a Li-ion battery by draining it after a crash is emerging as a preferred solution to mitigate fire risk. When a Volt crashes, GM currently sends out a team to drain the battery. The company is working on a battery draining tool to be distributed next year to dealers and possibly to first-responders as well.
NHTSA reportedly had not followed GM's procedures for deactivating the battery pack after an accident. The agency has stated that based on available data, there’s no greater risk of fire with a Volt than with a traditional gasoline-powered vehicle. The Volt’s prismatic-type Li-ion cells are supplied by LG Chem.
Discussions of the NHTSA Volt fire are a hot topic (no pun intended) here at the SAE Battery Summit, where advanced-battery researchers are updating the audience on cell chemistry R&D programs and related technology developments.
Dr. Anderman told the audience he hopes the NHTSA Volt fire wasn’t caused by a manufacturing-related issue at either the cell or pack levels. He also noted the potential impact of any battery-related EV fire on vehicle electrification overall.
“Any projections of EV volumes by President Obama or McKinsey & Co. or anybody will be wiped out immediately if there’s a major recall on any of the EVs,” he told the audience.