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GM works to ensure its new Hummer EV avoids battery defects


A 2019 Chevrolet Bolt EV caught fire at a home in Cherokee County, Georgia on Sept. 13, 2021, according to the local fire department.

Cherokee County Fire Department

DETROIT – As General Motors scrambles to repair defects that caused fires in at least 13 Chevrolet Bolt EVs, the automaker is aggressively working to ensure the same problems don’t seep into their next-generation Ultium batteries and its highly anticipated relaunch of an all-electric version of the Hummer this fall.

The new power system is crucial to the automaker’s future as it pivots to exclusively offer electric vehicles by 2035. The batteries and the company’s entire Ultium system – platforms, motors and other components – are expected to underpin every EV for GM for the foreseeable future.

Problems with the Bolt – the company’s flagship mainstream EV – have led the automaker to recall every one of the electric cars since production began in 2016. Fixing the vehicles, including completely replacing some batteries entirely, is expected to cost $1.8 billion.

That cost – averaging roughly $13,000 per vehicle – highlights a gamble for automakers planning to use common platforms or battery cells to power massive amounts of vehicles. It’s likely to cost a lot to fix if there is a problem.

It’s one of the reasons officials throughout GM have aggressively been working “around the clock” to fix the issues and ensure future electric vehicles such as the GMC Hummer EV and Cadillac Lyriq — two of the first GM models to use its Ultium batteries — don’t have the same problems. They are also developing wireless technology to enable GM detect possible defects earlier.

“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,” Mike Harpster, chief engineer of electrification propulsion for GM, told CNBC during a deep dive into GM’s upcoming Lyriq. While there is no fault in the defect or the problem, it’s important to consider how the vehicle and pack react. Both of those areas are important to us and we have been very active.

It is not just its internal efforts that the automaker has been focusing on. GM Chief Financial Officer Paul Jacobson recently said GM engineers are working with LG Chem, which makes the batteries, to “clean up the manufacturing process” and implement some “GM quality metrics” at its plants.

GM on Monday announced fixes to the manufacturing process of the battery cells as well as updated monitoring software for the vehicles. They will be used in future models, Tim Grewe (GM’s director of electrification strategy), told reporters Monday.

GM seeks reimbursement from LG for the parts that were defective in South Korea’s and Michigan plants.

New battery plants

The new Ultium battery uses new chemistries, production methods, and safeguards, but GM will still use the lessons from its current manufacturing process.

Harpster who served as chief engineer on the Bolt EV propulsion system, stated that there are many improvements that can be made to that process. This is not at the cell, but also at the module and pack levels. LG is our partner for everything that we did in the past. We’re using all those lessons to take it to the next stage.

Grewe stated earlier this month to CNBC that the new production “is not any more susceptible” than the current company.

He said that any contaminant can create problems. The battery plants we currently have are subject to all sorts of inspections.

GM CEO Mary Barra last month said the new plants will be “applying all of General Motors’ quality processes to the manufacturing process,” signaling the company expects better quality controls in place in the new facilities.

Every day, we work to validate and test what our employees are doing. When we find an issue like this, and this again, happens to be two rare manufacturing issues in the same cell, we’re going to address it,” she said Aug. 4 during an interview on CNBC’s Squawk Box.

Barra stressed Ultium is an entirely new battery system, however producing batteries will always be more volatile than assembling a traditional vehicle. It is not possible to drain the batteries and then fill them up with gas later, as automakers are able to do.

CNBC previously heard Sam Abuelsamid, principal analyst at Guidehouse Insights, say that “the manufacturing processes will really have to be tightened up.” It’s necessary to deal with how batteries behave. They are sensitive to heat and contamination. They can be very sensitive.

This photo was released by the Vermont State Police of the Chevrolet Bolt EV which caught on fire in the driveway at the home of Timothy Briglin (a Democrat).

Vermont State Police

Wireless monitoring system

The “rare manufacturing defects” in the Bolt EVs are a torn anode tab and folded separator that when present in the same battery cell increase the risk of fire, according to GM.  

GM is still working to fix the problems in the production of these cells, however it could be able detect them sooner with Ultium vehicles.

The battery cells’ new capabilities will allow them to communicate wirelessly and provide GM with data 24 hours a day to diagnose potential problems. Officials say Bolt EVs can’t make any major updates to their software remotely and communicate only when they are charging or running.

General Motors unveiled its new modular platform and its battery system, Ultium on March 4, 2020, at the Tech Center campus of Warren, Michigan.

Photo by Steve Fecht for General Motors

“It’s all over-the-air updateable,” Grewe said. The wireless system would likely have helped the company to determine if a problem existed “a bit quicker,” he said.

He said that the wireless system could reset the battery software remotely, which would lower the chance of fires. Bolt EV owners currently have to either do the reset themselves or bring it in to a dealer.

All Ultium vehicles will have a wireless battery monitoring system that can monitor and refocus sensors and modules as necessary, helping to protect the battery’s health throughout its lifespan.