But based on testing so far, regulators believe the batteries are safe and don’t pose a greater fire risk than gasoline-powered engines, a National Highway Traffic Safety Administration official told The Associated Press. The official requested anonymity in order to speak freely.
The car that caught fire was tested May 12 by an agency contractor at a Wisconsin facility using a relatively new side-impact test intended to replicate crashing into a pole or a tree, the official said.
Three weeks later, while the car was parked at the test facility, it caught fire and set several nearby vehicles on fire. A NHTSA investigation concluded the crash test damaged the battery, which later led to the fire.
Lithium-ion batteries have a history of sometimes catching fire when damaged.
General Motors spokesman Greg Martin said the test did not follow procedures developed by GM engineers for handling the Volt after a crash.
“Had those protocols been followed after this test, this incident would not have occurred,” he said.
Martin said the Volt is safe.
After the Volt fire, NHTSA and GM each replicated the crash test and waited three weeks, but in neither case did the cars catch fire, officials said. Nor were the cars’ batteries damaged in those tests, officials said.
The NHTSA official said the agency has been unable to explain why the Volt’s battery was damaged in one test but not in two others conducted in exactly the same manner. NHTSA, along with the Department of Energy, plans to conduct more tests next week on Volt batteries and is continuing to monitor cars already in use.
Government and GM officials said they are unaware of any similar fires among the 5,000 Volts now on the road.
NHTSA is also asking manufacturers who currently have electric cars on the market, or who plan to introduce electric vehicles in the near future, for more detailed information on their battery testing and what procedures they have established for discharging and handling batteries, including recommendations for reducing fire risks.