General Motors says it is working around the clock to ensure its upcoming Ultium lithium-ion battery packs do not feature the same thermal runaway issues as the batteries found in the Chevy Bolt EV and Chevy Bolt EUV.
The Chevy Bolt EV and Bolt EUV feature a 65 kWh lithium-ion battery pack manufactured by Korean supplier LG Energy Solution. While the Ultium batteries are larger, they will use similar LG pouch cells as the battery pack used in the Bolt EV and Bolt EUV. The battery pack fires in the Bolt EV and Bolt EUV are believed to be caused when a torn anode and a folded separator are present within the same pouch cell.
Despite the Ultium packs using a similar-style pouch cell, GM is confident it can prevent future thermal runaway issues with the Ultium packs and develop software to detect battery problems before they lead to a fire, Mike Harpster, chief engineer for electrification propulsion at GM, told CNBC in a recent interview.
“There’s a commitment across the company to not only address the issue with the LG cells and the Bolt but also make sure that all the future products are set up for success,” he explained. “There’s not creating the fault or defect, but there’s also how the pack and the vehicle respond to it. And on both those fronts, we’re moving very aggressively.”
GM has said it is now working with LG to “clean up the manufacturing process” at the company’s plants and put GM-approved quality control practices in place. Production of the revised Bolt battery packs is expected to begin later this month, with GM set to start installing them in customer vehicles in October. While the Bolt packs are manufactured by LG, the new Ultium battery packs will be produced by a newly formed joint venture between GM and LG called Ultium Cells LLC. The first Ultium Cells LLC plants are currently being constructed in Ohio and Tennessee.
GM expanded its recall of the 2017-2019 Chevy Bolt EV in August to include all Bolt EV models manufactured between the 2017 and 2022 model years, as well as the 2022 Bolt EUV. The recall now includes 141,000 vehicles and is projected to cost the automaker upwards of $1.8 billion to address. The automaker has said it will be seeking compensation for the recall from LG Energy Solution, which produces the battery packs at two plants in Korea and Michigan.
Tesla CEO Elon Musk drew the EV community’s attention recently after he said in a tweet that the risk of thermal runaway in large pouch cells like the ones GM uses is “dangerously high,” and that Tesla “strongly recommends against their use.” Tesla uses cylindrical battery cells in its vehicles that have a similar appearance to a traditional AA battery.