Description of the Defect: The root cause is the simultaneous presence of two rare manufacturing defects in the same battery cell. The condition appears to be aggravated by routinely charging the battery to a full or n" />
In November 2020 the National Highway Traffic Safety Administration (NHTSA) opened an investigation into Chevrolet Bolt electric cars after several complaints of vehicles catching fire while parked and unattended. One vehicle was plugged into a charger in the owner’s driveway and the second was parked but not plugged in. Additional research found a third vehicle, a 2017 Bolt EV with similar burn patterns. In all three cases, fire damage appeared to come from the battery compartment under the rear seat. The investigation resulted in the recall of approximately 50,000 2017-2019 Chevrolet Bolt EVs built with design level N2.1 battery cells. As an interim remedy, dealers reprogrammed the hybrid propulsion control module to limit full charge to 90% until a final remedy was developed.
As part of the final repair, dealers will use diagnostic tools to identify potential battery anomalies and replaced battery module assemblies as necessary. The fix includes the installation of advanced onboard diagnostic software that detects potential issues related to changes in battery module performance. Once the remedy procedure is completed the battery is restored to it's 100% charging capacity.
As GM continued to monitor field data and investigate potential battery fires, they became aware of an alleged battery fire in a vehicle outside of the recall population. An inspection of this vehicle determined that the probable origin of the fire was the vehicle’s high-voltage battery pack. GM continued to conduct tear downs and physical inspections on high-voltage battery cells.
This work included used cells returned from the field and new cells never installed into vehicles; cells of different design levels; and cells produced and assembled into cell-module assemblies at different LG facilities. In August 2021 GM's updated tear down data and analysis indicated that both defects could be present in cells installed into vehicles outside of the original recall population.
In August 2021, GM’s safety engineering team conducted a detailed analysis of this new data and have decided to expand the NHTSA recall 21V560 to include all 2019 model year Chevrolet Bolt EVs not covered by the prior recall, plus all 2020 – 2022 Chevrolet Bolt EVs and all 2022 Chevrolet Bolt EUVs.
Description of the Defect: The root cause is the simultaneous presence of two rare manufacturing defects in the same battery cell. The condition appears to be aggravated by routinely charging the battery to a full or nearly full state of charge after it has been substantially depleted. If the batteries in these are charged to full capacity, or very close to full capacity, the batteries may pose a risk of fire.