In order to achieve the 2050 net-zero transformation goal and effectively promote a zero-carbon energy system, the international community has paid increasing attention to the development of electrification of transportation vehicles in recent years. Governments of various countries have also increased their efforts to subsidize the electric vehicle market and provide related tax incentives. The United States also committed to increasing subsidies for electric vehicles through the Inflation Reduction Act of 2022 in August 2022. This move has also contributed to the rapid increase in American private demand for electric vehicles.
However, while electric vehicles are booming, more and more firefighting units around the world have noticed that not only are electric vehicles difficult to extinguish when they accidentally catch fire, but firefighters often need to use more water than traditional fuel vehicles to control the fire. How Effectively extinguishing fires caused by electric vehicles seems to have become an issue that fire agencies are increasingly paying attention to.
Canadian news station "CTV News" pointed out that on average, firefighting units need to use 40 times more water than ordinary fuel vehicles to extinguish electric vehicle fires. The water consumption per firefighting is as high as 40,000 gallons (approximately 151,400 liters), and fire trucks It is usually impossible to carry such a huge amount of water. If there is not enough water source or fire hydrants at the fire site, the electric vehicle may burn for several days before extinguishing.
"It is definitely a challenge for us to have electric vehicle fires in areas where firefighting facilities are lacking, which is why firefighting units must now develop new technologies to combat the problem of electric vehicle fires." Perth County, Ontario, Canada (Perth County) fire chief and fire educator Bill Hunter said so.
Thayer Smith, director of the Austin Fire Department in Texas, USA, also expressed similar views in an exclusive interview with the British newspaper The Independent, emphasizing that 500 to 1,000 gallons of fuel vehicles are usually used after a fire. (approximately 1892 liters to 3785 liters) of water to extinguish the fire. However, once the lithium battery of an electric vehicle starts to burn, 30,000 (approximately 113,500 liters) to 40,000 gallons of water are needed to extinguish the fire, and sometimes the water consumption even exceeds this range.
Why is it difficult to put out a fire caused by an electric vehicle?
"The Wall Street Journal" reporter John Keilman said in an exclusive interview with Julie Chang, host of the newspaper's podcast program "Tech News Briefing", that electric vehicles Cars mainly store energy through lithium ions inside lithium batteries. However, lithium is a very reactive metal element. Once the lithium battery is penetrated by foreign objects or its own system fails and a short circuit occurs, it is very likely that it will not require any chemical reaction. Thermal runaway problem occurs under such conditions.
Thermal runaway will have destructive consequences for lithium batteries and vehicles. Due to the rapid heating of lithium batteries, fire sources will appear. During the process, toxic gases such as Hydrogen fluoride and Hydrogen chloride will be produced due to the burning of plastics and metals. Continuous thermal runaway of lithium batteries will also release a large amount of flammable gases, increasing the risk of steam explosions in electric vehicles. Once an electric vehicle explodes, a jet-like, highly directional flame will appear and burn intensely for a long time.
The British newspaper The Guardian stated that in addition to requiring a large amount of water and being difficult to extinguish, electric vehicle fires may cause "fires that appear to be under control, but are actually under control due to the continuous thermal runaway phenomenon in the exothermic reaction of lithium batteries". The situation of "heating up again and re-igniting" makes it more difficult for firefighters to deal with electric vehicle fires.
The Wall Street Journal also reminded that all electric vehicle drivers should pay attention to the information displayed by the sensors in the vehicle. If any abnormality is found, they should stop driving immediately and report the problem. Many drivers of fuel vehicles should not continue after discovering that the engine failure warning light is on. Driving, and even if the electric vehicle catches fire, it should not be extinguished by itself. Remember that this is not a fire that can be easily extinguished with a traditional fire extinguisher.
Are electric vehicles more likely to cause fires than fuel vehicles?
The Guardian pointed out that although the danger of fire caused by the lithium battery of electric vehicles is greater than that of fuel vehicles, according to current statistics from all walks of life, the possibility of electric vehicles causing fires is significantly lower than that of traditional gasoline or diesel vehicles.
Colin Walker, head of the transport department of the British think tank "Energy and Climate Intelligence Unit" (ECIU), said: "All the data we have collected shows that electric vehicles are much less likely to catch fire than combustion vehicles, and many Even if a fire occurs in a fuel vehicle, it will not be recorded."
According to statistics from the Swedish Civil Emergency Response Agency (MSB) quoted by the Guardian in 2022, there are an average of 3.8 fires per 100,000 electric or hybrid vehicles (Hybrid vehicles), but there are 3.8 fires per 100,000 fuel vehicles. As many as 68 vehicles caught fire.
The newspaper also stated that in Norway, the country with the highest sales of electric vehicles in the world, the number of fires in fuel vehicles is four to five times that of electric vehicles. Tesla, the largest electric car company in the United States, also emphasized that the number of fires caused by gasoline and diesel vehicles in the United States from 2012 to 2021 was 11 times higher than that of Tesla electric vehicles.
In addition, according to a survey by EV Fire Safe, an electric vehicle fire protection agency funded by the Australian Department of Defense, the probability of a fire occurring while riding in an electric vehicle is 0.0012%, while the chance of a fire caused by a fuel vehicle is as high as 0.1%.
How do firefighting units deal with fires spread by electric vehicles?
"Wall Street Journal" reporter Kelman explained that most fire agencies in the United States are still trying to find the most effective way to deal with electric vehicle fires. Although many firefighters still use a large amount of water on the burning electric vehicles, at this stage, Relevant units have found more efficient methods of extinguishing fires. For example, extending the nozzles of fire water jets to the bottom of electric vehicles to sprinkle water can improve fire extinguishing efficiency, because this is where lithium batteries are usually stored.
Some firefighting agencies have also found that directly covering the burning electric vehicle with a fire blanket can shorten the burning time. In addition, the vehicle can also be hung into a large container mixed with water, sand and gravel. This strategy can have the opportunity to avoid If the fire spreads to the surrounding area, it can also block the contact between the burning vehicle and oxygen, thereby shortening the burning time.
When Technology News Briefing host Julie Zhang asked whether car manufacturers and electric vehicle companies must also pay attention to the difficulty of extinguishing electric vehicle fires, Kelman said that many car manufacturers have begun to study related technologies and hope that In the future, there will be opportunities to eliminate the difficulty of extinguishing fires in electric vehicles.
For example, most electric vehicles currently use liquid lithium batteries as the power source to drive electric vehicles. However, liquid lithium batteries are flammable and may cause fire, explosion or re-ignition due to battery leakage or improper charging. Therefore, at this stage, Already, car manufacturers have developed solid-state batteries that are less likely to burn and have high stability. Once the technology matures, it will have the opportunity to provide longer battery life and faster charging than liquid lithium batteries.
Kelman further pointed out that some car manufacturers and car manufacturers are developing the latest battery systems, hoping to shut down the operating system when the electric vehicle power supply is abnormal, thereby reducing the risk of spontaneous combustion of the vehicle. It is reported that the German car company Audi has applied for a battery patent in 2022. If the control system of the brand's electric vehicle detects that the vehicle is at risk of imminent spontaneous combustion, it will immediately inject the built-in power of the electric vehicle into the battery system. fire extinguishing agent. Audi said that the design can extinguish the fire on its own in the shortest time and minimize the cost of firefighters' disaster relief.
※ This article is reprinted with authorization from "Key Comment Network", the original title "Firefighting water consumption is 40 times higher!" Why are electric vehicle fires more difficult to put out than fuel vehicle fires? 〉. CC co-creation licensing terms do not apply.
References:
*The Wall Street Journal (November 13, 2023), Firefighters vs. EVs: Why EV Fires Are Harder to Put Out
*The Guardian (November 20, 2023), Do electric cars pose a greater fire risk than petrol or diesel vehicles?
*The Independent (August 12, 2021), Tesla in fireball crash needs 40 times the water as regular car to put out flames, says fire crew
*CTV News (December 20, 2023), Fire officials raise concerns over EV fires
*EV Fire Safe, Risks with EV battery fire
Source: Environmental Information Center
