General Motors announced Friday that it is recalling an unspecified quantity of 2017-2019 Chevrolet Bolt EVs as a result of a NHTSA investigation into battery fires. GM was able to confirm the presence of an issue and narrow down the circumstances to a batch of batteries supplied by LG Chem’s facility in Ochang, South Korea, which may catch fire when near a maximum state of charge.
"As you may be aware, the National Highway Traffic Safety Administration launched an investigation into a few reports the agency received from Chevrolet Bolt EV owners about potential fires," Chevrolet said in a message to owners that was also posted on its web site. "GM had already been investigating these reports prior to that announcement, in cooperation with NHTSA."
Fires were initially reported in 2017, 2018, and 2019 models, and the three EVs were left with a similar burn pattern on or around the rear seats. After investigating, NHTSA published a bulletin explaining that the fires seemingly started in the Bolt's battery compartment and spread to the cabin. In cooperation with GM, NHTSA eliminated outside factors, such as charging equipment.
The two were able to confirm five total incidents of fire that occurred in batteries near a maximum state of charge, however, the exact cause of the fires still remains under investigation. GM is distributing a software update to dealer service departments that will limit customer vehicles' maximum state of charge to 90%, which should eliminate the conditions required for a fire while GM attempts to find a permanent solution.
In the meantime, NHTSA urges owners to keep their Bolts parked outside and away from structures. They are being encouraged to manually set their batteries' maximum state of charge to 90% within the Bolt EV's built-in charging controls. For 2017-2018 models, this means selecting the "Hill Top Reserve" charge mode; owners of 2019 models can enable "Target Charge Level" and set it to 90%. The video embedded above describes the procedure for both variants.