Has EV Thermal Runaway, AKA Daisy-Chain Fires, Been Solved?

Could this alleviate some consumer worries?

By: Jonathon Klein

Oct 14, 2024 at 8:08am ET

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I've been reporting on electric vehicles for over a decade now. And the one question I'm still asked about, as well as still report on, is about thermal runaway.

For those who've never heard the term, it's when a single battery cell on an electric vehicle is heated to the point of combustion and, rather than it extinguishing itself as designed, gets so hot it sets the next cell on fire. And then the next. And the next. And so on and so forth.

The occurrence is rare among the millions of EVs on the road. But when it does occur, it's all over the news and, as you'd expect, is catastrophic in its destruction. It's so violent that, given the intensity of the fires that result, it tends to set alight other cars, structures, and more, which is definitely cause for alarm.

And insurance companies, property owners, and others have taken note of an EV thermal runaway event being so destructive that some have outright banned them from parking garages and developments due to their inherent risk of causing such fires. Hard to insure something when a single car's battery could set the whole place on fire.

But the folks at LG Chem, the people behind most of the EV battery cells that consumers use on a daily basis, believe they've come up with a solution for thermal runaway. And if they're correct, that'd mean a lot safer EVs, and potentially quelling dissent. It's also a pretty simple solution.

According to our sister site InsideEVs, the thermal runaway fix involves just a single protective layer between the cathode and current collector. LG Chem states, "The thermal runaway suppression material developed by LG Chem is a composite material that changes its electrical resistance based on temperature, acting as a 'fuse' that blocks the flow of electricity in the early stages of overheating."

Think of it as a mood ring. When the material hits a certain temperature threshold, it changes its molecular composition and ceases to conduct the current, i.e. it goes from a cool, soothing, calm blue, to red hot. That, in theory, would halt the propagation issue that is at the heart of thermal runaways. And in testing, when the batteries did catch fire, they quickly extinguished themselves without setting the others alight.

What do you think?

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LG Chem is planning on testing the material throughout next year, but the company states that given the relative simplicity of the fix, it could adopt it in future battery cells in the coming years.

If it proves real, that'd do a lot to alleviate some of the fear of EVs. It'd also likely help owners more easily insure their cars, motorcycles, and electric bicycles. Who knows, maybe this along with solid-state batteries could finally bring us the EV future we've been promised. You know, the one without all the fires, issues, range-anxiety, and other issues...