BMW has expanded its recall of vehicles over a potential battery issue to most of its U.S. plug-in hybrids for the 2020 and 2021 model years. 

The recall, issued for a smaller subset of vehicles last month, now has been expanded to 4,509 U.S. vehicles. That includes the 2020-2021 BMW 530e models (including xDrive and iPerformance), 2020-2021 xDrive30e, 2020-2021 Mini Cooper Countryman All4 SE, 2020 BMW i8, 2021 BMW 330e (including xDrive), 2021 BMW 745Le xDrive, and 2021 BMW X5 xDrive45e. 

At root are manufacturing issues within the battery pack, related to welding debris left inside the pack that could create a short between modules. The component manufacturer is listed as Samsung. 

2021 BMW 530e plug-in hybrid system

BMW reports in its recall notice that the high-voltage battery in the plug-in hybrids “may not have been produced to specifications,” such that when charging the battery, “this could lead to a short-circuit and, in rare cases, a thermal event.”

With last month’s recall, BMW said that the remedy is an inspection of the battery pack and the free replacement of faulty modules when necessary. This month, under the expanded campaign, BMW says the recall remedy is still being developed, and in the meantime drivers are instructed not to charge their vehicles—or even to use manual mode, Sport mode, or the shift paddles, all of which increase regenerative braking and the rate at which the battery is charged. 

Owner notification is due to start on Nov. 23.