WASHINGTON (AP) - A safety investigation of the lithium-ion batteries in General Motors Co.'s Chevrolet Volt is under way to assess the risk of fire in the electric car after a serious crash, the National Highway Traffic Safety Administration said Friday.
One Volt battery pack that was being closely monitored following a government crash test caught fire Thursday, the safety administration said in a statement. Another crash-tested battery emitted smoke and sparks, the statement said.
GM, which was informed of the investigation on Friday, said in a statement that the Volt "is safe and does not present undue risk as part of normal operation or immediately after a severe crash."
The fires are in addition to a battery fire in a crash-tested Volt six months ago.
NHTSA learned of a possible fire risk involving damaged Volt batteries in June when a fire erupted in a Volt that was being stored in a parking lot a test facility in Burlington, Wis. The fire was severe enough to cause several other vehicles parked nearby to catch fire as well.
The car had been subjected to a side-impact crash test more than three weeks earlier, on May 12, during which the battery was damaged and its coolant line ruptured.
Last week's tests of three battery packs were designed to replicate the May test. In that test, the Volt was subjected to a simulated side-impact collision into a narrow object like a tree or pole followed by a rollover, the agency said.
The first battery tested last week didn't catch fire. But a battery test on Nov. 17 initially experienced a temporary temperature increase, and on Thursday caught fire. Another battery tested on Nov. 18, which was rotated 180 degrees within hours after the test, began to smoke and emit sparks shortly after the rotation.
The tests were conducted by NHTSA and the Energy and Defense departments at a defense facility near Hampton Roads, Va.
So far, no fires have been reported in Volts involved in roadway crashes, NHTSA said. More than 5,000 of the vehicles have been sold.
It's too soon to tell whether the investigation will lead to a recall of any vehicles or parts, but the government will ensure consumers are informed promptly if that occurs, the agency said.
With electronic safety systems that are part of the car, "GM knows real time about any crash significant enough to potentially compromise battery integrity," the automaker said. "Since July, GM has implemented a post-crash protocol that includes the depowering of the battery after a severe crash, returning the battery to a safe and low-powered state."
Electric vehicles are critical to President Barack Obama's plans to reduce U.S. dependence on foreign oil. He has called for putting 1 million of the vehicles on the road by 2015.
Safety testing hasn't raised concerns about electric vehicles other than the Volt, NHTSA said.
"NHTSA continues to believe that electric vehicles have incredible potential to save consumers money at the pump, help protect the environment, create jobs and strengthen national security by reducing our dependence on oil," the agency said.