Final month, a Mercedes Benz EQE 350 electrical car caught fire in a South Korean condominium constructing’s underground parking storage. Reportedly, 23 folks 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 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 homeowners from “overcharging” their automobiles 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 typically secret info.)
Knowledge from the Nationwide Transportation Security Board, the US’s impartial federal investigation company, reveals that the dangers of electrical car battery fires are low. The truth is, very low. An evaluation of that information by one insurance company prompt that greater than 1,500 gasoline automobiles catch on hearth per 100,000 gross sales, in comparison with simply 25 electrical automobiles.
On some stage, hearth is a threat of any sort of battery expertise. Professionals speak concerning the “hearth triangle”—the three-ingredient recipe for ignition. Fireplace wants oxygen, a spark, and gasoline. As a result of the purpose of a lithium-ion electrical car is to retailer vitality, the gasoline is all the time there. EV batteries are supposed to be tightly packed and remoted from different elements of the automobile, however an incident like a catastrophic crash would possibly shortly introduce oxygen and warmth to the brew.
Constructing a Fireplace-Proof(ish) Battery
Some battery makers have taken steps to cut back the danger of their batteries catching hearth. The primary is to create stringent manufacturing processes and requirements. That is necessary as a result of any kind of flaw in a battery may result in an inferno, says Venkat Srinivasan, who research batteries and directs the Argonne Collaborative Heart for Vitality Storage Science on the US’s Argonne Nationwide Laboratory.
To know why battery manufacturing issues to fireside threat, you must 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 vitality. 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 expenses up and down, it may create a spark, open the battery cell, and permit oxygen to return dashing in and presumably expose all the battery pack to fireside.
These kinds of battery-making screw-ups do occur. In August, Jaguar told some 3,000 homeowners of its 2019 I-Tempo SUV to park their automobiles exterior due to hearth threat, which was linked to 3 fires. The producer behind these automobiles’ packs, the South Korean agency LG Vitality Resolution, has been topic to a US road safety probe since 2022. BMW, General Motors, Hyundai, Stellantis, and Volkswagen have all recalled automobiles over battery dangers (a few of them in hybrid moderately than all-electric automobiles). However these conditions are uncommon. By way of strong manufacturing processes, “one can by no means make the danger of fireplace completely zero, however good firms have minimized the danger,” says Srinivasan.
Much less Fireplace-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 car battery has been made primarily from nickel and cobalt. Batteries with this make-up cost shortly and maintain numerous vitality, which is nice for EV use as a result of drivers of automobiles 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 sort 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 hearth then turns into self-sustaining and laborious to place out.
