LG Chem said it had developed a highly heat resistant plastic which can significantly delay thermal runaway in lithium ion batteries used in electric vehicles (EVs).

The South Korean parent of the world’s second largest EV battery manufacturer, LG Energy Solution (LGES), said the new material has the longest flame blocking duration in the world.

LG Chem said in-house tests showed the material ’prevented flame propagation for over 400 seconds above 1,000 degrees, 45 times longer than general flame-retardant plastics’, which would provide more time for the safe evacuation of vehicle occupants in the case of a battery fire. The material is also said to have superb dimensional stability, maintaining its shape despite extreme temperature changes.

LG Chem said thermal runaway is a main cause of fire in electric vehicle batteries, which occurs when battery cells suffer stresses from various sources causing overvoltage and over discharge short circuits. Fires start once the cell’s internal temperature rises above a certain level.

Lithium ion batteries are also highly reactivity to water, meaning that fires are hard to extinguish with water. Last year several EV fires in the US, which caused severe injury, were found to have been caused by defective LGES batteries.
LG Chem said its newly developed special flame retardant material is a high function engineering plastic consisting of various material groups such as polyphenylene oxide (PPO), polyamide (PA) and polybutylene terephthalate (PBT).