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Faults found in lithium-ion battery packs but no remedy identified in billion dollar EV recall

Mon, 09/06/2021 - 15:57 -- paul Crompton

A torn anode tab and a folded separator on cells used in Chevrolet Bolt electric vehicle battery module were to blame for the billion dollar recall of more than 140,000 vehicles amid fire concerns.

General Motors and LG Chem said the defects increase the risk of a fire, but GM has said it does not know what is causing those defects in the manufacturing process. 

The teams are tearing down battery packs, inspecting cells and monitoring how LG packs the cells into the modules, then into a battery pack at LG Electronics.

Daniel Flores, GM’s communications manager, told BEST: “Engineers from GM and LG are working around the clock to eliminate those defects.   

“At this time, I can’t speculate on how long that process will take, however, we will not begin recall repairs in customer vehicles until we are confident in the safety of LG’s products.

GM's engineers are studying LG's manufacturing process in conjunction with a recall of Bolt EVs (2017-2022) and Bolt EUVs (2022).

LG builds the battery cells at its subsidiary— LG Energy Solution Michigan— facility in Holland, Michigan.

Last month, GM announced it had discovered manufacturing defects in certain battery cells produced at LG’s manufacturing facilities “beyond” the Ochang, Korea, plant. 

Both firms are working to rectify the cause of these defects. In the meantime, GM is pursuing commitments from LG for reimbursement of this field action.

GM doesn’t know if the defects are in every Bolt that is being recalled.

The vehicle OEM will keep its Orion Assembly plant idled and not start repairs on the vehicles until it is “confident its supplier can make a defect-free EV battery that does not pose a potential fire risk”, reported the newspaper Detroit Free Press (DFP).

GM is working to develop a software technology to enable a dealership's service technician to identify whether a specific module is defective and just replace that defective module, but in lieu of that the firm is going to replace all the five modules in all the vehicles.

Rare defects detected

Last month, GM and LG identified the simultaneous presence of “two rare manufacturing defects” in the same battery cell as the root cause of battery fires in Chevrolet Bolt EVs. 

GM will replace defective lithium-ion battery modules in Chevrolet Bolt EVs and EUVs with new lithium-ion modules. 

Before the modules are replaced, GM has advised vehicles owners to: 

  1. Set vehicle to a 90% state of charge limitation using Hilltop Reserve mode (for 2017-2018 model years) or Target Charge Level (for 2019-2022 model year) mode. If you are unable to successfully make these changes, or do not feel comfortable making these changes, GM is asking you to visit your dealer to have these adjustments completed
  2. Charge your vehicle more frequently and avoid depleting the battery below approximately 70 miles (113 kilometers) of remaining range, where possible
  3. Park your vehicle outside immediately after charging and do not leave your vehicle charging indoors overnight

Out of an abundance of caution, GM has said it will replace defective battery modules in Chevrolet Bolt EVs and EUVs with new modules, with an expected additional cost of aaround $1 billion.

Doug Parks, GM executive vice president, global product development, purchasing and supply chain, said: “Our focus on safety and doing the right thing for our customers guides every decision we make at GM.

“As leaders in the transition to an all-electric future, we know that building and maintaining trust is critical. GM customers can be confident in our commitment to taking the steps to ensure the safety of these vehicles.” 

This new recall population includes:

  • 9,335 (6,989 in the U.S. and 1,212 in Canada) – 2019 model year Bolt EVs that were not included in the previous recall
  • 63,683 (52,403 in the U.S. and 9,019 in Canada) – 2020–2022 model year Chevrolet Bolt EVs and EUVs

To provide customers peace of mind, batteries with these new modules will come with an 8-year/100,000-mile limited warranty (or 8-year/160,000 km limited warranty in Canada).

GM is working aggressively with LG to increase production as soon as possible. GM will notify customers when replacement parts are ready. 

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