Last month, a Mercedes-Benz EQE 350 electric car caught fire in the underground parking lot of an apartment complex in South Korea. According to reports, 23 people were taken to the hospital and about 900 cars were damaged. The fire reached temperatures of more than 2,700 degrees Fahrenheit (1,500 degrees Celsius) and took firefighters nearly eight hours to extinguish.
The incident follows a series of rapid changes in the country, including the acceleration of a planned EV battery certification program and a new rule in Seoul that prevents owners from “overcharging” their vehicles in underground parking lots. This led to policy changes. Automakers are also being asked to do something they don’t normally do: reveal the origins of the batteries in their electric cars. (In early September, the South Korean government announced that it would require automakers to disclose this confidential information.)
Data from the National Transportation Safety Board, an independent federal law enforcement agency, shows that the risk of electric vehicle battery fires is low. Very low, in fact. An insurance company analyzed the data and suggested that for every 100,000 cars sold, more than 1,500 gasoline cars catch fire, compared to just 25 electric cars.
All types of battery technology present some level of fire risk. Experts talk about the “fire triangle,” or three-ingredient fire recipe. Fire requires oxygen, a spark, and fuel. The purpose of a lithium-ion electric car is to store energy, so the fuel is always there. Although EV batteries are designed to be tightly packed and isolated from the rest of the car, an accident like a major one can quickly introduce oxygen and heat into the beer. there is.
Building a fireproof(ish) battery
Some battery manufacturers have taken steps to reduce the risk of batteries catching fire. The first is creating rigorous manufacturing processes and standards. Venkat Srinivasan, a battery researcher and director of the Argonne Collaborative Center for Energy Storage Science at Argonne National Laboratory in the US, says this is important because any defect in a battery can lead to catastrophe. says it’s important.
To understand why battery manufacturing is important to fire risk, you need to understand the basics of lithium-ion batteries. A battery’s anode and cathode store lithium, and they are connected by an electrolyte, a liquid chemical that passes lithium ions between them to store or release energy. For example, if small metal particles get into the electrolyte through unclean manufacturing processes and remain charged while the battery is being charged, they can create a spark that opens the battery cells and allows oxygen to flow in. The entire battery pack may catch fire.
Battery manufacturing failures like this do happen. In August, Jaguar told nearly 3,000 owners of its 2019 I-Pace SUV to park their vehicles outdoors due to fire hazards related to three fires. South Korean company LG Energy Solutions, which manufactures these vehicle packs, is the subject of a U.S. traffic safety investigation starting in 2022. BMW, General Motors, Hyundai, Stellantis, and Volkswagen have all recalled vehicles (some even recalled) due to battery risks. hybrid vehicle rather than an all-electric vehicle). However, this situation is rare. Through sound manufacturing processes, “fire risk cannot be completely eliminated, but good companies minimize it,” says Srinivasan.
Low flammable chemicals
The good news is that fire-resistant batteries are already being used in cars, thanks to special battery chemistry that makes them less likely to catch fire. Since the first Tesla was launched in 2008, standard electric car batteries have been made primarily of nickel and cobalt. Batteries in this configuration charge quickly and retain a lot of energy. This is ideal for EV use, as drivers of battery-powered vehicles enjoy longer range and faster charging. Additionally, cold temperatures in the range of 400 to 300 degrees Fahrenheit (210 to 150 degrees Celsius) increase the likelihood of “thermal runaway.”
Thermal runaway is a condition in which a lithium-ion battery enters a kind of fire-hazard loop. Damaged battery cells generate heat and flammable gases, which generate even more heat and flammable gases that begin to heat up nearby battery cells, ejecting even more batteries. heat and gas. This will allow the fire to continue burning on its own, making it difficult to put out.
