GM announces fix for Volt battery fire issue

General Motors will strengthen the structure of its Chevrolet Volt and add two devices to the extended-range electric car’s battery coolant system to address concerns about the model’s safety after fires following three test crashes last year.

The Detroit carmaker described the changes on Thursday as a voluntary “customer satisfaction programme” rather than a recall mandated by safety regulators.

Referring to an investigation into the Volt’s safety by the National Highway Traffic Safety Administration (NHTSA), Mark Reuss, head of GM’s North American operations, said, “We are optimistic that this will have a positive outcome.” NHTSA had no immediate comment.

The response to the Volt fires is being closely watched in view of the accelerating roll-out of electric cars by most big carmakers. Questions have been raised in the past about potential hazards from the cars’ huge battery packs, but little evidence of actual defects had emerged until the Volt fires.

Since then, California-based Fisker Automotive has recalled 239 of its upscale Karma electric cars to repair a battery defect.

Even so, NHTSA has said that it is not aware of any road crashes causing battery-related fires in electric vehicles.

The Volt repairs involve about 12,000 cars that have already been built. The changes will also be incorporated into future vehicles, including the Opel Ampera, a European version of the Volt.

GM declined to disclose the cost of the repairs and said they would add only a couple of pounds to the weight of the vehicle. “We will stop at nothing to ensure that our customers are satisfied,” Mr Reuss said.

GM disclosed last November that Volt lithium-ion batteries had caught fire in three separate tests after being hit and rotated to simulate a side-impact collision into a narrow object such as a tree or a pole, followed by a rollover. The fires began days and weeks after the crashes.

GM said that the fires were caused by leaked battery coolant coming into contact with electronic circuit boards.

The repairs involve strengthening part of the Volt’s structure to protect the battery in a side collision, as well as adding a sensor to monitor coolant levels and a bracket to help prevent overfilling the battery with coolant.

GM said that it had conducted tests using the new equipment. “There was no intrusion into the battery pack and no coolant leakage in any of the tests,” it said.