- LG Chem has developed a temperature-sensitive safety layer in EV batteries to suppress thermal runaway.
- The material acts as a 'fuse' to blocks the flow of electricity in the early stages of overheating.
- The development comes amid nationwide panic in South Korea after multiple EV battery fires.
Electric vehicles are statistically far less likely than gas-powered cars to catch fires. One study shows that gas cars are up to five times more prone to igniting. But when EVs do catch fires, they can be frightening and pose serious safety risks—not just for owners but also for the first responders who face unique challenges in extinguishing them.
South Korean battery maker LG Chem—which supplies EV batteries to Tesla, Ford and many others—says it has a breakthrough solution to prevent such fires. Its battery researchers worked with a special engineering team at the Pohang University of Battery Technology in South Korea to develop a special layer within the battery pack to suppress thermal runaway, which causes batteries to burn uncontrollably.
The research comes at a critical time for EV fire safety in Korea. Recently, a Mercedes EQE engulfed in catastrophic flames in an underground garage in Incheon, causing nationwide panic and skepticism regarding EV safety. This caused Mercedes-Benz EV sales to stumble in the country, causing panic selling of used EVs.
For starters, an EV battery fire can occur due to cell damage, prolonged flooding, short circuits and crashes, among a few other reasons. When that happens, thermal runaway occurs, where the battery overheats uncontrollably, to a point where it can keep burning for hours by itself, without oxygen.
As the cells heat up, they can cause neighboring cells to heat up too, creating a chain reaction. This rapid rise in temperature can lead to the battery going up in flames or even exploding. EVs have cooling systems and safety sensors, but thermal runaway can still happen in rare cases.
LG Chem announced on Tuesday that its one of its research and development teams and the Pohang University battery team developed a temperature-responsive "safety reinforced layer" to suppress thermal runaway.
"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," the company said in a statement.
LG Chem, through its battery subsidiary LG Energy Solution, is a battery supplier to several EV makers. LGES batteries are used in the Shanghai-made Tesla Model 3, some Ford Mustang Mach-E and E-Transit models, VW ID.4, and the discontinued Chevy Bolt EV, among many others.
The safety material is a one-micrometer thin layer, about one hundredth the thickness of human hair, situated between the cathode and the current collector. When temperatures rise beyond 90 degrees Celsius and up to 130C, this layer alters the molecular structure to suppress the flow of current.
LG Chem says the layer is flexible. It can lower the suppression when it senses battery temperatures dropping. During testing, the batteries apparently did not catch fire at all, or extinguished flames shortly after they appeared.
The battery researchers tested Nickel-Cobalt Manganese (NCM) and Lithium-Cobalt Oxide (LCO) batteries. Seventy percent of the NCM batteries equipped with the thermal suppression layer did not catch fire. The 30% that did ignite extinguished within seconds. None of the LCO batteries with the safety layer saw any fires.
LG Chem says it plans to conduct safety testing in large-capacity EV batteries through 2025, and it can be applied to mass production in a short period of time. In automotive parlance, a short period of time can be at least a few years, if not decades. Either way, if LG Chem can make this available commercially down the line, it could play a huge role in improving public sentiments about the safety of EV batteries—not just in Korea, but across the globe.
