Final month, a Mercedes Benz EQE 350 electrical automobile caught fire in a South Korean house constructing’s underground parking storage. Reportedly, 23 folks had been despatched to the hospital and roughly 900 automobiles had been broken. The fireplace reached temperatures of greater than 2,700 levels Fahrenheit (1,500 levels Celsius), and took firefighters nearly eight hours to extinguish.
The incident led to a collection of swift policy changes within the nation, together with the acceleration of a deliberate EV battery certification program and new guidelines in Seoul that ought to forestall house owners 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 mentioned it could require automakers to reveal this usually secret info.)
Knowledge from the Nationwide Transportation Security Board, the US’s impartial federal investigation company, reveals that the dangers of electrical automobile battery fires are low. The truth is, very low. An evaluation of that knowledge by one insurance company instructed that greater than 1,500 gasoline automobiles catch on hearth per 100,000 gross sales, in comparison with simply 25 electrical autos.
On some degree, hearth is a danger of any form of battery know-how. Professionals speak in regards to the “hearth 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 may 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 hearth. The primary is to create stringent manufacturing processes and requirements. That is necessary as a result of any form of flaw in a battery may 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 know why battery manufacturing issues to fireplace danger, it’s a must to perceive the basics of lithium-ion batteries. The battery’s anode and cathode retailer lithium, and they’re related by an electrolyte, a liquid chemical that passes lithium ions between the 2 to retailer or launch power. If, say, a tiny particle of steel will get into that electrolyte by way of an unclean manufacturing course of, and it retains getting electrified because the battery costs up and down, it may create a spark, open the battery cell, and permit oxygen to return dashing in and presumably expose the complete battery pack to fireplace.
These kinds of battery-making screw-ups do occur. In August, Jaguar told some 3,000 house owners of its 2019 I-Tempo SUV to park their autos outdoors due to hearth danger, which was linked to 3 fires. The producer behind these autos’ packs, the South Korean agency LG Power Resolution, has been topic to a US road safety probe since 2022. BMW, General Motors, Hyundai, Stellantis, and Volkswagen have all recalled autos over battery dangers (a few of them in hybrid somewhat than all-electric autos). However these conditions are uncommon. By stable manufacturing processes, “one can by no means make the chance of fireplace completely zero, however good firms 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, due to 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 plenty of 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 during which lithium-ion batteries enter a form of hearth 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 fireplace then turns into self-sustaining and arduous to place out.
