Will charging electric car batteries to just 90% reduce the risk of fire?

by times news cr
Dong-A Ilbo DB

The aftermath of the accident in which more than 100 vehicles were burned or damaged in an electric vehicle fire in an apartment building’s underground parking lot in Seo-gu, Incheon, is spreading like wildfire. As the public’s anxiety about electric vehicle fires grows, the government is discussing various measures, such as disclosing battery manufacturers and restricting underground parking for fully charged electric vehicles. In addition to these measures, the government plans to release comprehensive measures for electric vehicle fires, including electric vehicles themselves and infrastructure such as chargers, in early September.

According to the scientific community on the 15th, scientists are unanimous in saying that although this measure may be effective in reducing electric vehicle fire damage, it is difficult to see it as a final solution. Ultimately, they are saying that technology development to improve battery safety is necessary.

● Buffer Limits, “Not the Ultimate Solution”

As a measure to prevent electric vehicle fires, Seoul City has announced a policy to restrict electric vehicles that are over 90% charged from parking in underground parking lots. Based on the opinions of experts that it is difficult to extinguish electric vehicle fires in underground parking lots, they are banning the parking of 100% ‘buffered’ electric vehicles, which are known to have a higher risk of fire. In reality, conflicts are occurring as other residents block electric vehicles from entering underground parking lots.

Parking above ground can help fight electric vehicle fires, as it reduces damage in the event of a fire and makes it easier to fight the fire because it provides more space. Kim Do-yeop, a senior researcher at the Energy Convergence Materials Research Center at the Korea Research Institute of Chemical Technology, said, “If you park an electric vehicle above ground, the temperature of the vehicle in the summer may be higher than when it is underground, but the battery is under the floor of the vehicle and is not exposed to direct sunlight, so the temperature difference will not increase the risk to that extent.”

Will charging electric car batteries to just 90% reduce the risk of fire?

Electric vehicle charging stations in Seoul. News 1

Scientists believe that the battery charge level affects the difference after a fire rather than the possibility of a fire. This means that a car with a low battery charge can reduce the size of a fire, but the impact of a fire itself may be small. The reason why it is difficult to extinguish an electric vehicle battery fire is because a chain reaction occurs and the temperature soars in an instant, which is called a “thermal runaway.” If the battery charge level is low, the temperature required to start the thermal runaway chain reaction increases, reducing the possibility of a thermal runaway. In addition, even if a thermal runaway occurs, the overall temperature increase can be suppressed.

“A 90 percent charged battery is more chemically stable than a 100 percent charged battery, but it only makes a small difference after a fire starts rather than affecting the likelihood of a fire,” said Cho Soo-keun, a battery researcher at Pohang Accelerator Laboratory.

Researcher Cho also diagnosed, “The 90% charge standard may be a temporary measure. If the charge level is lower than half, the thermal runaway chain reaction is significantly weakened, but it is not easy to set a safety standard because battery cells are different for each manufacturer and the surrounding conditions are also diverse.” He continued, “First, it is best to prevent fires in the electric vehicle battery itself, and the infrastructure around the electric vehicle charger, etc.
“We need to make efforts to simultaneously prepare secondary and tertiary fire prevention measures outside the vehicle,” he said.

The electric car that was completely destroyed in the fire that broke out in the underground parking lot of Cheongna Apartment on the 1st, the second joint investigation site. News 1

The electric car that was completely destroyed in the fire that broke out in the underground parking lot of Cheongna Apartment on the 1st, the second joint investigation site. News 1

● Disclosure of battery manufacturers is desirable

Battery information has been called a trade secret in the industry and has not been clearly disclosed. However, as it was confirmed that the electric vehicle that caused the fire in the Incheon underground parking lot was equipped with a battery from a different manufacturer than previously known, voices calling for the battery manufacturer to be disclosed have grown louder. Accordingly, the government has decided to recommend that all electric vehicle manufacturers sold domestically voluntarily disclose their battery manufacturers.

Researchers believe that disclosing the battery manufacturers is a good thing, as it can encourage manufacturers to develop and manufacture batteries more responsibly. “If manufacturers are disclosed, battery manufacturers will also pay more attention to making safer batteries,” said Researcher Kim. “However, it may be a misunderstanding to think that Chinese batteries are of low quality,” said Researcher Cho. “Although the battery cell structure and other factors differ depending on the manufacturer, it is difficult to conclude that it is a problem with the battery itself, and there are many variables such as the body, so other factors may have been involved.”

Lee Byeong-gu, Donga Science Reporter [email protected]

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2024-08-16 06:03:23

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