Final month, a Mercedes Benz EQE 350 electrical automobile caught fireplace in a South Korean condominium constructing’s underground parking storage. Reportedly, 23 individuals have been despatched to the hospital and roughly 900 automobiles have been broken. The hearth reached temperatures of greater than 2,700 levels Fahrenheit (1,500 levels Celsius), and took firefighters virtually eight hours to extinguish.
The incident led to a sequence of swift coverage adjustments within the nation, together with the acceleration of a deliberate EV battery certification program and new guidelines in Seoul that ought to stop homeowners from “overcharging” their autos in underground parking garages. It has additionally pushed automakers to do one thing they wouldn’t usually: reveal who makes the batteries inside their electrical automobiles. (In early September, the South Korean authorities stated it could require automakers to reveal this usually secret data.)
Information from the Nationwide Transportation Security Board, the US’s unbiased federal investigation company, exhibits that the dangers of electrical automobile battery fires are low. In actual fact, very low. An evaluation of that information by one insurance coverage firm advised that greater than 1,500 gasoline automobiles catch on fireplace per 100,000 gross sales, in comparison with simply 25 electrical autos.
On some degree, fireplace is a threat of any type of battery know-how. Professionals discuss in regards to the “fireplace triangle”—the three-ingredient recipe for ignition. Hearth wants oxygen, a spark, and gas. As a result of the purpose of a lithium-ion electrical automobile is to retailer power, the gas is at all times there. EV batteries are supposed to be tightly packed and remoted from different elements of the automotive, however an incident like a catastrophic crash would possibly shortly introduce oxygen and warmth to the brew.
Constructing a Hearth-Proof(ish) Battery
Some battery makers have taken steps to scale back the chance of their batteries catching fireplace. The primary is to create stringent manufacturing processes and requirements. That is necessary as a result of any form of flaw in a battery might result in an inferno, says Venkat Srinivasan, who research batteries and directs the Argonne Collaborative Middle for Power Storage Science on the US’s Argonne Nationwide Laboratory.
To grasp why battery manufacturing issues to fireside threat, you must perceive the fundamentals of lithium-ion batteries. The battery’s anode and cathode retailer lithium, and they’re linked by an electrolyte, a liquid chemical that passes lithium ions between the 2 to retailer or launch power. If, say, a tiny particle of metallic will get into that electrolyte by an unclean manufacturing course of, and it retains getting electrified because the battery prices up and down, it might create a spark, open the battery cell, and permit oxygen to come back dashing in and probably expose the whole battery pack to fireside.
These types of battery-making screw-ups do occur. In August, Jaguar advised some 3,000 homeowners of its 2019 I-Tempo SUV to park their autos outdoors due to fireplace threat, which was linked to a few fires. The producer behind these autos’ packs, the South Korean agency LG Power Answer, has been topic to a US street security probe since 2022. BMW, Common Motors, Hyundai, Stellantis, and Volkswagen have all recalled autos over battery dangers (a few of them in hybrid slightly than all-electric autos). However these conditions are uncommon. By way of stable manufacturing processes, “one can by no means make the chance of fireside completely zero, however good corporations have minimized the chance,” says Srinivasan.
Much less Hearth-y Chemistries
The excellent news is that less-fire-prone batteries are already rolling round in automobiles, because of particular battery chemistries which can be tougher to ignite. For the reason that first Tesla hit the street in 2008, the usual electrical automobile battery has been made primarily from nickel and cobalt. Batteries with this make-up cost shortly and maintain numerous power, which is nice for EV use as a result of drivers of autos that use them get pleasure from longer ranges and sooner top-ups. They’re additionally extra prone to enter “thermal runaway” at decrease temperatures, within the 400- to 300-degrees Fahrenheit (210 to 150 levels Celsius) vary.
Thermal runaway is a state wherein lithium-ion batteries enter a type of fireplace doom loop: A broken battery cell produces warmth and flammable gases, which in flip produces extra warmth and flammable gases, which begins to warmth close by battery cells, which launch extra warmth and gasoline. The hearth then turns into self-sustaining and laborious to place out.