LG Chem material can suppress thermal runaway in batteries

LG Chem's Platform Technology research and development (R&D) team has developed a temperature-responsive safety reinforced layer (SRL), designed to suppress thermal runaway in batteries.

In collaboration with Professor Lee Minah’s team from the department of battery engineering at South Korea-based research university Postech, the material was analyzed while safety verification was conducted in partnership with LG Energy Solution. Research findings were published in the September edition of scientific journal Nature Communications.

LG Chem's thermal runaway suppression product 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 Seoul, South Korea-based company says its research team created the new material in the form of a thin layer, about 1 micrometer thick, positioned between the cathode layer and the current collector (an aluminum foil that acts as the electron pathway) in the battery. When the battery’s temperature rises beyond the normal range, between 90 and 130 degrees Celsius, the material reacts to the heat and alters its molecular structure to suppress the flow of current.

LG Chem says this suppression material is highly responsive to temperature, with its electrical resistance increasing by 5,000 ohms for every 1 C rise in temperature. The material’s maximum resistance is more than 1,000 times higher than at normal temperatures, and it also features reversibility, meaning the resistance decreases and returns to its original state and allows the current to flow normally again once the temperature drops.

According to the company, thermal runaway occurs when the cathode and anode inside a battery unintentionally come into direct contact, causing a short circuit and generating heat. Within seconds, the temperature can rise to nearly 1,000 C, leading to a fire. LG Chem says its thermal runaway suppression material is expected to be effective in preventing fires by quickly blocking the reaction path at the early stages of overheating.

In both battery impact and penetration tests, the company says batteries equipped with the new material either did not catch fire or had flames extinguished shortly after they appeared, preventing a full-blown runaway event. In a penetration test involving mobile lithium cobalt oxide (LCO) batteries, a nail was used to puncture the battery and only 16 percent of regular batteries did not catch fire. However, LG Chem says none of the batteries using the new material experienced fire incidents.

Additionally, the company says impact tests run on nickel cobalt manganese (NCM) batteries, in which a 10-kilogram weight was dropped onto the batteries, resulted in each standard battery catching fire. In contrast, the company says 70 percent of the batteries equipped with its new suppression material did not ignite at all, while the remaining 30 percent saw flames but were quickly extinguished.

LG Chem says it has completed safety verification tests for the new material in mobile batteries and plans to continue safety testing for large-capacity electric vehicle (EV) batteries through next year.

“This is a tangible research achievement that can be applied to mass production in a short period of time,” says Lee Jong-Ku, chief technology officer at LG Chem. “We will enhance safety technology to ensure customers can use electric vehicles with confidence and contribute to strengthening our competitiveness in the battery market.”