Chevy Bolt EV Battery Replacements Coming Soon in Fire-Risk Recall

General Motors said Monday it will start replacing battery modules in its Chevrolet Bolt EV electric cars as soon as next month, now that its battery supplier LG is again producing the necessary cells and modules. The company will first prioritize 2017–2019 Bolts built during times it believes defective cells were most likely to have been produced.

The replacements are the first long-term fix to address a recall underway since last November, when GM first identified 50,000 Bolt EVs from those model years that could have defective cells. The recall ultimately expanded to every Bolt EV and EUV made, a total of roughly 141,000 cars. Drivers of those cars have been advised to limit their charging, how deeply they discharge their batteries, and where and how they park their cars [see sidebar]. Owner discontent has surged, to the point that some Bolt EVs have been bought back by the company.

Now, a fix is in sight. GM said LG only resumed production of its cells and modules after it “implemented new manufacturing processes” in its plants in the Michigan cities of Holland and Hazel Park to eliminate two different defects in the cells, a torn anode tab and a folded separator, that could cause fires in the rare instance that both flaws occur in the same cell.

The companies didn’t provide further details about how the defects occurred or what specific changes to build processes had been made to eliminate them. But Tim Grewe, GM global electrification and battery systems director, confirmed during a media call that “interaction between the two [defects] is what causes the issue.”

Those same new manufacturing processes will be rolled out to all LG plants that supply cells to GM, the company said. GM will increase its frequency of individual cell checking, and work closely with LG to share manufacturing expertise in areas that apply to cell fabrication and assembly processes. It will also work with LG to “review and enhance its quality-assurance programs” as part of an effort to “provide confidence in its batteries” in the future.

GM said it is aware of 13 Bolt fires suspected to be linked to defective cells in the battery packs. No injuries or deaths are attributed to those fires, but all 141,000 Bolt EVs and EUVs built since December 2016 are being recalled. Meanwhile, GM has directed Bolt owners to follow specific recharging, usage, and parking protocols to reduce risk until their cars can be updated.

Production of both the Bolt EV and the new, larger Bolt EUV model was suspended last month. GM confirmed the Orion Assembly Plant’s lines will remain idle at least through the week of October 11 but didn’t give a date for resumption of Bolt production.

New Modules and Software Coming

As cell production under LG’s revised processes ramps up, GM will start to replace battery modules in existing Bolt vehicles. The company said it would “prioritize Chevy Bolt EV and EUV customers whose batteries were manufactured during specific build time frames” in which the company believes “the defects appear to be clustered.”

Affected Bolt EVs will receive a full set of new battery modules. Owners of 2017–2019 Bolt EVs whose modules are replaced will see the rated range of their cars rise from 238 to 259 miles. That comes from replacing the cars’ original cells with a newer and more energy-dense cell, boosting pack capacity from 60.0 to 65.0 kWh.

GM did not offer any estimates on how many vehicles it believed would require battery replacement, or how long the replacement of all affected Bolt modules would take. Chevrolet will notify “affected customers,” which is to say owners of existing Bolts, when new modules are available for their batteries.

Monitoring Batteries More Closely

Now that LG will be starting to supply replacement battery hardware, GM will also roll out new diagnostic software to be installed in every Bolt that monitors an expanded set of battery performance data. The goal is to look at more indicators than the existing software does, so the cars can alert drivers of any unusual readings in its battery’s electrical performance.

The program will detect “specific abnormalities that might indicate a damaged battery” and, GM says, will let the company prioritize damaged modules for replacement. Getting that software installed in a Bolt will require a visit to the Chevrolet dealership, however. Customers can start to schedule those visits in roughly 60 days, during the second half of November.