"Misconception That Electric Car Fires Extinguish Slowly and Spread Quickly"

Hyundai Motor: "Electric Vehicle Fear, Excessive Concern and Misinformation"

Hyundai Motor Company and Kia recently distributed reference materials on the 29th to clarify the facts amid various controversies following electric vehicle fires. The following is part of the content.

“Is it true that electric vehicle fires are difficult to extinguish due to thermal runaway and that the vehicle must be completely burned out for the fire to go out?”

Only partially true. Electric vehicle fires, like internal combustion engine vehicle fires, occur due to various factors. Most electric vehicle fires caused by external factors such as other components did not involve battery thermal runaway.

Battery packs have high fire resistance and heat resistance, so fires caused by factors other than the battery do not easily spread. Even if the battery catches fire, the latest electric vehicles are equipped with technology that delays thermal runaway propagation, allowing early extinguishing to prevent the fire from spreading extensively. Cho Sun-ho, head of the Gyeonggi Fire and Disaster Headquarters, said at a demonstration in July last year, “Initial suppression or containment of electric vehicle fires is not more difficult than that of internal combustion engine vehicles.”

On the 8th, as electric vehicle fires continue to occur, interest in the safety of electric vehicles is growing. At the entrance of an underground parking lot in Incheon, a notice prohibiting electric vehicles from entering is posted. Photo by Jinhyung Kang aymsdream@

The company also added that the belief that it takes a long time to completely extinguish the fire, resulting in greater damage, is a misunderstanding. Recently, technologies to reduce electric vehicle fire extinguishing time to around 10 minutes have been actively developed.

Hyundai Motor Company explained, “Even if initial suppression is quick, the vehicle is submerged in a water tank or covered with a smothering blanket for a certain period to manage any possible battery chemical reactions until all battery energy is depleted,” adding, “This process is safely conducted under the supervision of the Fire Agency and cannot spread damage to the surroundings, so there is no need to be anxious about the long fire extinguishing time.”

“Do electric vehicle fires spread faster and reach higher temperatures?”

There are inaccuracies in this claim. The heat energy of 1 kWh of battery capacity is 3.6 MJ (megajoules). One liter of gasoline contains 32.4 MJ. For the same capacity, internal combustion engine vehicles carrying higher energy fuel tend to have faster fire spread and higher external temperatures, the company explained.

A mid-sized gasoline vehicle has a 50-liter fuel tank, while an electric vehicle has an 80 kWh battery. If both are at 100% capacity, the heat energy is 1620 MJ for the gasoline vehicle and 288 MJ for the electric vehicle. The energy content of the gasoline vehicle is much greater than that of the electric vehicle.

According to a paper published by the Korean Society of Disaster Prevention in 2021, when a fire broke out in the gasoline and electric vehicle models of the compact car Ray, the gasoline vehicle fire spread faster and reached higher temperatures. Both vehicles had interior temperatures around 1300 degrees Celsius, but the exterior temperature was up to 935 degrees for the gasoline vehicle and 631 degrees for the electric vehicle. This indicates that the information claiming electric vehicle fires are uniquely hotter and cause greater surrounding damage is incorrect.

On the morning of the 2nd, police, firefighters, and other officials are conducting a joint investigation at the site of a fire in the underground parking lot of an apartment in Cheongna, Seo-gu, Incheon. The fire broke out at around 6:15 a.m. the previous day on the first basement floor of the apartment, involving a Mercedes-Benz electric vehicle, and was extinguished after 8 hours and 20 minutes.
[Photo by Yonhap News]

Is an underground parking lot more dangerous in case of fire?

When a fire occurs indoors, regardless of vehicle type, the role of sprinklers is most important. According to a paper published by the Korean Society of Fire Science and Engineering in April, activating sprinklers alone can prevent fire spread to adjacent vehicles.

In May, an electric vehicle fire occurred in an underground parking lot of an apartment in Gunsan, Jeonbuk, where sprinklers operated normally and the fire was extinguished within 45 minutes. Only two adjacent vehicles suffered damage due to firefighting activities, not fire. In contrast, the 2022 underground parking lot fire at the Daejeon Outlet resulted in seven deaths and hundreds of billions of won in losses because the sprinklers did not operate.

Hyundai Motor Company and Kia stated, “It is most important to thoroughly manage quality with battery cell manufacturers and prevent larger accidents through pre-diagnosis via the Battery Management System (BMS),” adding, “We will also strengthen measures to minimize blind spots in the battery anomaly notification system.”