Chevy Volt faces defect probe after two new battery fires

Federal auto safety regulators launched their first defect probe into the Chevrolet Volt on Friday after two Volt battery packs caught fire following simulated crash tests.

Despite the fires not involving customers, the probe gives General Motors exactly the kind of public black eye it wanted to avoid as it touted the Volt’s complicated combo of gasoline engine and lithium-ion battery pack as a rally flag for the company's technology.

Earlier this month, the National Highway Traffic Safety Administration revealed that a Volt battery pack had smoked and caught fire more than three weeks after a side-impact test where the car had been smashed into a pole at 20 mph. At the time, GM had said the agency had not followed the automaker’s procedures for discharging the battery following a crash, and had it done so, there would have been no fire.

Today, NHTSA said it had recorded two more fires after simulated crash tests on three of the Volt’s 390-lb. lithium-ion battery packs, rupturing their coolant lines and damaging their outer compartments. In one test, following the simulated crash, the battery pack began to smoke and throw sparks after it was rotated 180 degrees. Another pack that had been tested last Thursday and only shown a slight increase in temperature caught fire on Thanksgiving.

NHTSA says the tests were meant to show how the Volt might respond to real-world impacts side-on into narrow objects such as poles or trees. The Volt's battery packs hold 32 kWh of electricity when fully charged, or about what a typical American household uses in two days; it can travel about 40 miles on a full charge before the gas engine kicks in to provide an additional 340 miles of travel.

The agency said it opened the probe because it was “concerned that damage to the Volt’s batteries as part of three tests…have resulted in fire.”

In a statement, GM said it would work with the agency, maintaining “the Volt is safe and does not present undue risk as part of normal operation or immediately after a severe crash. “

No fires have been reported by Volt owners since the car went on sale last December, and two garage fires that started with Volts present were later tied to other heat sources. But GM has sold only 5,003 through October, still vowing to hit 10,000 copies this year and 45,000 next year. Even the whiff of trouble about the Volt's technology will only make that target harder to reach.

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