EV battery fires are back in the news as Hurricane Helene batters the southeastern United States, submerging EVs and sending some of their batteries into thermal runaway. Between them and the Tesla Semi fire that shut down an interstate for days, it would seem that EV battery fires are a growing hazard that we have yet to reckon with. But that risk may be temporary, as LG Chem claims to have developed a material that can stop battery fires before they start—or even kill them after they do.
In a paper published in the scientific journal Nature Communications, the company outlines the invention of what it calls a “Safety Reinforced Layer.” Likened to an electrical fuse, this consists of a one-micrometer-thick layer of composite material between the cathode and “current collector” that changes its molecular structure when temperatures exceed a “normal” range of 90ºC to 130ºC (194ºF to 266ºF). This drastically increases the layer’s electrical resistance by 5,000 Ohms per 1ºC, reaching a maximum resistance exceeding 1,000 times that of normal operating temps. This helps isolate the cathode and anode, contact between which is a cause of battery fires. These chemical changes are said to reverse themselves when the battery temp returns to normal, so overheating a battery doesn’t mean it’s cooked (so to speak).
In plain English, it’s a thin layer that chemically disrupts the battery circuit and protects its most reactive parts when the battery overheats. Sounds good, but how well does it work? Well, during impact testing, LG Chem says adding the material greatly reduced rates of fires, and even led to fires quickly extinguishing themselves.
When piercing conventional lithium cobalt oxide batteries, LG Chem said the packs caught fire 84 percent of the time, while nickel cobalt manganese batteries always caught fire when 10-kilogram (22-pound) weights were dropped on them. In batteries with LG’s added “fuse” however, the fire rate of lithium batteries dropped to a claimed zero percent. The nickel batteries’ fire rate dropped to 30 percent—and all fires went out shortly afterward.
LG Chem says that previous attempts to develop a material with these capabilities either compromised a battery’s energy density or reacted too slowly to be useful. This current material, however, has proven promising enough to escalate to large-scale testing, which will continue in car-sized batteries through 2025.
“This is a tangible research achievement that can be applied to mass production in a short period of time,” said LG Chem’s chief technology officer, Lee Jong-gu. “We will enhance safety technology to ensure customers can use electric vehicles with confidence and contribute to strengthening our competitiveness in the battery market.”
Still, all seemingly groundbreaking developments like this need a reality check. Even if this material is as effective as early testing suggests, and it’s as easily rolled into production as executives indicate, it’ll be a long time before the material significantly impacts the EV landscape. For starters, it doesn’t sound like it’ll be production-ready until at least 2026, at which point it’d only make its way into EVs from companies that LG Chem supplies. It’s unclear how LG Chem will handle the intellectual property rights of this development, which will seriously affect its propagation into the wider battery manufacturing industry.
Even if it tries to reserve the material for itself, it’s likely that the knowledge of how to make it will spread—be it by industrial espionage or independent development at other companies. In any case, it’s a heartening sign for EV proponents, and a potential solution to the EV battery fire question once and for all.
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