Final month, a Mercedes Benz EQE 350 electrical automobile caught fire in a South Korean condominium constructing’s underground parking storage. Reportedly, 23 individuals had been despatched to the hospital and roughly 900 vehicles had been broken. The fireplace 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 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 vehicles. (In early September, the South Korean authorities stated it might 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 company prompt that greater than 1,500 fuel vehicles catch on hearth per 100,000 gross sales, in comparison with simply 25 electrical automobiles.
On some degree, hearth is a threat of any form of battery expertise. 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 vitality, 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 rapidly introduce oxygen and warmth to the brew.
Constructing a Hearth-Proof(ish) Battery
Some battery makers have taken steps to cut 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 type of flaw in a battery may result in an inferno, says Venkat Srinivasan, who research batteries and directs the Argonne Collaborative Middle for Vitality Storage Science on the US’s Argonne Nationwide Laboratory.
To grasp 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 linked 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 costs up and down, it may create a spark, open the battery cell, and permit oxygen to come back speeding in and presumably expose the whole battery pack to fireside.
These types 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 outdoors due to hearth threat, which was linked to a few 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 fairly than all-electric automobiles). However these conditions are uncommon. By 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 vehicles, because of particular battery chemistries which might be tougher to ignite. Because the 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 rapidly and maintain plenty of vitality, which is nice for EV use as a result of drivers of automobiles that use them get pleasure from longer ranges and quicker top-ups. They’re additionally extra more likely 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 fuel. The fireplace then turns into self-sustaining and onerous to place out.
