Quality Magazine

Post-Crash Volt Fire Prompts New Safety Study

November 18, 2011

(Story via Edmunds AutoObserver ) Federal regulators, stressing they see no consumer safety issue, have launched a new study of lithium-ion batteries in electric vehicles after a battery pack for a Chevrolet Volt caught fire three weeks after the car was crashed in a side-impact collision test. The Volt fire occurred in June at the National Highway Traffic Safety Administration’s test facility in Wisconsin, where the wrecked Volt was being stored. Since then, NHTSA has contacted all major automakers with EVs in their lineups or in the future product plans with questions about lithium-ion battery safety. Both General Motors and NHTSA have tried to replicate the post-crash fire but have not been able to, a GM spokesman said. While lithium is highly flammable and there have been several instances of lithium-ion batteries in laptop computers catching fire, automakers use multiple safety systems in their EV battery packs to safeguard against heat build-up and other “thermal incidents” that could lead to EV battery fires.

Indeed, GM suggested in a statement that the fire at the NHTSA facility occurred because testers did not de-energize the Volt’s battery after the side-impact crash test and stored the wrecked car with a live battery pack. It appears that coolant that leaked after the crash came into contact with the battery and was ignited. NHTSA, which is looking into automakers’ procedures for “draining” EV batteries after collisions, said in a statement that it has no reason to believe that electric vehicles are any more dangerous – or fire-prone – than conventional gasoline vehicles. Separately, Nissan North America, which has been selling the all-electric Leaf hatchback since December, said that there have been no reported incidents of a Leaf battery fire. Both the Volt and the Leaf have been given 5-star crash-test safety ratings by NHTSA. The agency said that its chief concerns in the wake of the Wisconsin blaze is that tow operators, wrecking ad storage yard personnel and safety responders all are aware of the need to de-energize EV batteries and of the process involved.

More than 8,000 Leafs and 5,000 Volts are on the road in the United States and only two other Volt- involved fires have been reported and neither has been a lithium-ion battery fire. In the most recent case, a garage at a North Carolina home burned on Oct. 30 and early speculation centered on the home charging station in the garage. But in a report today, the Green Car Reports blog quotes a Mooresville, N.C. fire investigator as saying that his preliminary findings in a much-reported garage fire involving a Volt show that neither the car nor the home charging unit were the cause. The Volt was hooked up to the charging station and early reports speculated that the charger had malfunctioned.

But the deputy fire marshal for the county said his early findings show that the blaze started elsewhere in the garage and then involved the Volt and the charging station. GM, Nissan, NHTSA, Siemens – maker of the charging station – and power supplier Duke Energy all have sent investigators to the Mooresville fire site. In the first incident a garage in Connecticut burned, destroying a Volt and a homemade Suzuki-based electric car that was parked next to it. Fire investigators determined that the fire did not originate with either vehicle or their chargers.

Jim Federico, GM’s chief engineer for electric vehicles, said in a statement that the company “is working with other vehicle manufacturers, first responders, tow truck operators and salvage associations with the goal of implementing industry-wide protocols” for safe handling and storage of electric vehicles and their batteries in the aftermath of a crash. GM, he said, has its own protocols to “depower the battery of an electric vehicle after a significant crash” and has engineered the Volt with multiple on-board safety systems. The Volt, he said, “ is a safe car.”