Recently, the world has witnessed a strong development of Electric cars. In Vietnam, electric cars are still new with only a few representatives such as VinFast VF e34 and VF8, Porsche Taycan, Audi E-tron, Hyundai Ioniq 5, and some new Chinese electric cars entering the market like Wuling Hongguang Mini EV.
In addition to range and charging time, Fire risk is also one of the things that many people are concerned about when it comes to electric cars. Especially in the current context, when fire hazards in crowded residential areas make it difficult for fire trucks to access, causing serious consequences to people and property. The question is whether electric cars are more likely to catch fire than gasoline cars? Which type of vehicle is more prone to fire and explosion?
Are electric cars more likely to catch fire than gasoline cars?
The main reason for electric car fires is the battery. On the other hand, gasoline cars have multiple causes such as electrical component failures, fuel/liquid leaks, exhaust system overload, overheated engines, etc. Therefore, if compared to the flammability of traditional gasoline cars, electric cars are still much lower. In fact, the number of electric car fires is not too high.
Electric cars have a much lower chance of catching fire than gasoline cars
According to the National Transportation Safety Board (NTSB), a total of 16,051 hybrid cars caught fire in accidents. The corresponding figure for gasoline cars is 199,533 cases. Meanwhile, there were only 52 electric car fires.
Tesla claims that gasoline cars have an 11 times higher fire catch rate than their electric cars. The company says the best comparison ratio is fire rates per 1.6 billion kilometers driven. The electric car manufacturer stated that 300,000 Tesla cars on the road have traveled a total of 12 billion kilometers and reported about 40 fires. This figure is equivalent to 5 fires per 1.6 billion kilometers driven. In contrast, gasoline cars have a fire rate of 55 fires per 1.6 billion kilometers driven.
How do Li-ion batteries in electric cars catch fire?
Lithium-ion (Li-ion) batteries in electric cars are prone to fire due to their composition. However, car manufacturers have methods to prevent Li-ion battery fires. A Li-ion battery consists of four main components: the cathode, the anode, the electrolyte, and the separator.
A fire in a Li-ion battery pack usually occurs due to a short circuit in one or more battery cells, generating high heat. If a car’s Li-ion battery is damaged due to collision, fire, or water ingress, a short circuit can occur. This causes the battery cells to release energy and heat up, resulting in a “thermal runaway” state. This chain reaction can lead to battery failure or explosion, causing the fire to spread.
Illustration of the fire process of an electric car battery, from short circuit to thermal runaway and ignition.
Even in the case of an electric car being submerged in water, pollutants or salt can cause the battery to short-circuit, especially after the water recedes. Movements of the electric car or a damaged battery, such as when the car is being towed, can also cause a short circuit.
The heat generated by the fire, the thermal runaway of adjacent battery cells, or short circuits can melt the porous foam separator between the cathode and anode of a battery cell. This causes the battery cell to continue releasing heat and generating flammable gas. As a result, the entire battery pack may catch fire. “Heat can transfer to adjacent battery cells and become a chain reaction,” Barth explained.
The biggest difference compared to gasoline fires is the time it takes for an electric car to catch fire. Gasoline fires almost occur immediately when gasoline catches a spark or flame and spread quickly. In contrast, battery fires often require a period of time to accumulate enough heat before igniting. In some cases, this delay is good because people inside the car accident can escape before the fire occurs. In some other cases, the battery cells, even after being extinguished, can reignite after hours or even days, creating difficulties for rescue and repair work.
Illustration of a Lithium-ion battery pack in a Tesla car
Electric car fires are much more intense and harder to extinguish than gasoline fires
As mentioned above, electric cars are less prone to fires than cars using conventional gasoline engines. However, once a fire occurs, the lithium-ion battery in an electric car is much harder to extinguish. Currently, there are no effective and fast fire suppression measures for electric car fires.
The biggest difference compared to gasoline cars is that conventional fire foams cannot extinguish electric car fires. Instead, firefighters have to cool down the electric car’s battery to prevent fire and thermal runaway.
“Lithium-ion batteries produce their own heat and oxygen“, said Andrew Klock, product and development director of the American Firefighters Association. Therefore, cutting off the external oxygen supply does not stop the fire, and spraying foam has no effect. To extinguish an electric car fire, firefighters will have to spray a large amount of water into the battery pack to cool it down.
Firefighters extinguishing a fire caused by a Tesla electric car
The majority of the electric car’s batteries are located underneath the car, so spraying water on the body or engine compartment has no effect. “You need to spray water under the car“, Knock explained further.
According to the National Fire Protection Association, extinguishing an electric car fire with water requires more than 110,000 liters of water, about 20-25 times more than gasoline cars, and takes a long time.
Above are the most basic knowledge about electric car batteries, their fire-causing principles, and firefighting methods. It can be seen that both electric cars and gasoline cars themselves have a high potential for fire and explosion, so users need to be extremely careful to ensure their own safety, family safety, and social safety.
The post The Undisguised Reality: Are Electric Cars or Gasoline Cars More Prone to Fire? appeared first on xe.today.
