- LG Chem says it’s developed a new material capable of preventing ‘thermal runaway’ in EV batteries
- In testing, the material helped stop battery fires from starting, or extinguished them in seconds
- The company says it can apply the tech on a mass-production scale “in a short period”
Battery fires in electric vehicles (EVs) can be catastrophic and difficult to extinguish, but a solution may be on its way. LG Chem, based in Seoul, South Korea, said it has developed material that can suppress thermal runaway. That’s when the electrical current flowing through the battery cells causes them to overheat, raising their temperature and running the risk of a fire.
The temperature-responsive material is 1/100th the diameter of a human hair, and is placed inside the battery cell. When it detects the early stages of overheating, it reacts “like a fuse,” the company said, blocking the reaction path. The company published its findings in a research paper in the scientific journal Nature Communications, and said the product can be “applied to mass production in a short period.”
The material, which changes its electrical resistance based on temperature, is positioned in the battery between the cathode layer and a layer of aluminum foil used as the electron pathway, known as the current collector. When the battery temperature rises above normal, which is between 90°C (194°F) and 130°C (266°F), the material alters its molecular structure to suppress the flow of current. It is also reversible, so that when the temperature drops, the material returns to its original state and allows the current to flow again.
Thermal runaway is when the battery’s cathode and anode unintentionally make direct contact, causing a short-circuit. Within seconds, the battery’s temperature can rise to almost 1,000°C (1,832°F). LG Chem said thermal runaway is a leading cause of EV battery fires, and the material is expected to be “effective in preventing fires by quickly blocking the reaction path at the early stages of overheating.”
In tests involving both impact and penetration, batteries with the suppression material either didn’t catch fire at all, or extinguished the flames shortly after they started. In another penetration test where a nail was used to puncture lithium cobalt oxide batteries, 84% of regular batteries caught fire, while none did when equipped with the suppression material.
When tests were performed to drop a 10-kilogram (22-lb) weight on nickel cobalt manganese batteries, all of the standard batteries caught fire. Among the batteries with the suppression material, 70% did not ignite, while 30% caught fire but the flames extinguished within seconds.
No timeline was given for when batteries with the material could go on the market, but LG Chem said it has completed safety verification tests in mobile batteries, and will continue testing large-capacity EV batteries through next year.
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