Bolt Batteries Could Catch on Fire As They Charged Near 100%

General Motors had been asking 2017-2019 Bolt owners to park outside and limit their car's range until there was a more permanent solution to prevent the battery from catching on fire as it nears a full charge.

In April of 2021, GM announced that new software updates have the ability to detect potential issues related to changes in battery module performance before problems can develop.

What Was Causing Bolt Batteries to Catch on Fire? ∞

The Bolt uses a high-voltage battery system with pouch battery cells from a company called LG Chem. It's similar to the battery found in other EVs such as the Hyundai Kona.

GM believes there is a defect somewhere within some of the batteries that triggers a short-circuit as the battery approaches a full charge.

Owner stories spark an investigation ∞

Multiple reports of fires were sent in to NHTSA which led to an investigation being opened in October 2020. The investigation determined that something goes wrong with the battery only as it nears a full charge.

Meanwhile, GM confirmed five battery fires out of the 68,667 vehicles under investigation. Certainly not widespread, but you don't mess with fire.

Bolt Battery Recalls ∞

In April of 2021, GM announced a recall to prevent the battery fires from happening in two phases:

1. Dealers will utilize diagnostic tools and look for battery anamolies. If problems are detected the battery module assembly will be replaced.
2. A software update will be installed that can alert drivers of potential problems before they happen.

Previously, GM asked 2017-2019 Bolt owners to limit their battery's charging capacity and park their cars outside until a better fix could be installed.

Software updates to temporarily limit the charging capacity ∞

The recall updates the vehicle's software and limits the battery's charging capacity to 90%. The theory being if the battery can't fully charge then it also can't trigger that short-circuit.

The downside is the car's estimated range on a single charge drops from 238 miles to 214 miles. The upside is you won't wake up to a smoldering pile of metal where your car used to be.

The software will be installed by authorized dealers, but there are some ways owners can manually restrict the battery's charging capacity as well.

Setting "Hilltop Reserve Mode" in the 2017-2018 ∞

If you own a 2017-2018 Bolt, use the car's Hilltop Reseve mode which will limit the batteries charge capacity.

Changing the "Target Charge Level" in the 2019 ∞

If you own a 2019 Bolt, change the car's Target Charge Level setting to 90%. This video shows you how around the 2:00 mark.

Why some 2019 models and all 2020 models are excluded ∞

Some of the 2019 model year Bolts use battery cells from a Holland, Michigan plant not LG Chem. Those models are not in danger of this problem.

The 2020 model year Bolt uses a 66kwh battery that does not have the same risks.

Lawsuit Says Range Anxiety Deepened By Latest Recall ∞

It didn't take long for the first lawsuit to be filed post-recall as Torres, et al., v. General Motors LLC. was filed in December 2020.

The plaintiff says the recall is causing him "range anxiety" and that he's worried the range will further be limited by the colder winter months.

Personally I'd have more anxiety over the very likely scenario of my car catching itself on fire than losing an estimated 24 miles per charge, but that's just me.

Is the range even worse due to cell low-voltage condition? ∞

It sounds like the plaintiff has had range anxiety for quite some time and this latest update just pushed him over the edge. The suit references a customer satisfaction program sent out in mid 2018 about potential propulsion loss and over-estimated range numbers.

In service campaign #18125, titled Loss of Propulsion High Voltage Battery Without Notification, GM says:

Certain 2017-2018 model year Bolt EV vehicles may have a condition where the software will not detect the difference in the state of charge between the cell groups of the battery and over predict the indicated battery range.

And that...

The current software may not provide sufficient warning prior to a battery cell low range condition, which may result in a loss of propulsion.

It feels like a reach.