Electric cars also catch fire as in conventional vehicles. We discuss the main reasons for an electric car fire, how to tackle it, etc. today.
Electric vehicles slowly capture automotive market all over the world. The negative impacts of gasoline vehicles on the environment make the electric vehicle as an alternative to them. Alternative fuel vehicles are also developed and tested, but electric cars are the winners who are going to make future transportation.
Even though the electric vehicle is not a zero pollutant vehicle, the quantity of environment pollution is much lesser in an electric vehicle. Of course, they are zero tailpipe emission vehicles.
But the electricity to operate the vehicle is still generated mainly from burning coals, that pollutes the environment. The best part is that the coal-based electricity generating stations have an efficiency of around 40%. And an electric vehicle has an efficiency of 90%.
So the total efficiency to convert the energy from coal to mechanical energy in an electric vehicle is 90 % x 40% = 36 %
But the efficiency of an IC engine vehicle is around 16-27%
So an electric car is greener than Internal Combustion engine cars!
Electric vehicle fire: How an EV catches fire and how to extinguish it?
The high voltage battery in an electric car is a fire hazard. But they are not as inflammatory as the gasoline. As far as gasoline cars are considered, fossil fuel catches fire and damages the vehicle in accidents.
You shall watch the video from Brock Archer about High Voltage Firefighting
.. Read the excerpts from the video ..
The fire service responds to over 200,000 vehicle fires annually just in the US alone with the increased popularity of hybrid and electric vehicles. Your chances of encountering a high-voltage battery in a vehicle fire increase every day in this short training video.
They have teamed up with CAL FIRE the NFPA and advanced extrication to bring you best practice when responding to electric and hybrid vehicle fires.
Step #1: Identification of Vehicle
The fire fighting for IC engine vehicle and electric vehicle are different. So it’s essential to identify if the vehicle is an electric or IC engine based.
One important step when responding to an incident involving a hybrid or electric vehicle fire is to identify the vehicle. This identification process starts with the reporting party.
But it may be that the rescue team arrive at the incident and then have to identify the vehicle from there. This can be difficult when the vehicles involved in fire after the knockdown of the vehicle which will be handled in the same way as a conventional vehicle.
We can take the necessary steps to identify the vehicle. The formal identification for a hybrid or electric vehicle is simply the badging and branding on the outside of the vehicle.
We can look on the inside of the vehicle for our informal identification possibly in the engine compartment trunk luggage compartment or just throughout the vehicle.
More information on identifying high-voltage vehicles can be found by visiting the NFPA ZEB safety training program.
Step #2: Locate the battery of the electric car
Once we’ve identified that we’re fighting fire at a hybrid or Battery electric vehicle, we need to find the battery. Locating the battery is important for two reasons.
First of all, we need to make sure that we’re able to cool the battery if it’s been exposed to heat. This will require locating the battery in the vehicle.
We also want to identify the location of the battery so that we avoid it during our overhaul operations.
We never want to cut or crush a high-voltage battery or open it up to extinguish it. The personal protective equipment required for responding to a hybrid or electric vehicle fire remains the same as a conventional vehicle.
SCBA in full structural PPE is adequate protection for responding to vehicle fires involving high-voltage batteries as we mentioned earlier. It’s important to apply water directly to the high-voltage battery in order to effectively cool it.
It’s not always possible to get direct access to the battery in most hybrid vehicles. We can lift up the luggage compartment or trunk area to apply water to the battery. If that area has been involved in fire much of the battery coverings may be melted away giving you better access on vehicles.
With floor pan mounted batteries we may need to lift the vehicle slightly in order to get water onto the floor pan battery. In conducting that technician level operation be sure that your personnel is trained and equipped for the task and that care is taken to not interact with that battery during your lifting assignment.
To evaluate if a battery has been exposed to heat or if it’s involved in thermal runaway we can simply observe the battery and listen to the battery. If we see smoke or steam coming off the battery or we hear any popping noises from the battery this indicates that the battery is involved in a thermal event.
Step #3: Cool the electric car battery
We can also use our thermal imaging cameras to evaluate the battery’s temperature. If the battery requires cooling we simply use water to cool the battery directing your hose stream at the battery in one location that’s been heated for a period of time. And then moving on to another location in the battery was found to be best practice rather than sweeping the battery with your host stream.
How the heat and fire spread through a battery varies dramatically. The variables are based on how the manufacturer has put the battery together. The charge of the battery and where the battery was exposed to the heated water has been identified as the best extinguishing agent and a cooling agent for lithium-ion high voltage battery fires.
Research and case studies have proven that it can take between 500 and 8,000 gallons of water. Later we’ll talk about actively cooling the battery and we’ll cover best practice for the application of water on to the high voltage battery.
Suffocating agents such as foam and dry chemical are going to be ineffective in cooling your high voltage battery.
In addition to cooling the battery with the application of water on the case, we can also effectively cool the battery by applying water inside the battery. This is only possible when a vent or other natural opening has occurred like in the case of a collision ripping the battery partially open.
If we have the opportunity to apply the water inside the battery this is the most effective way to cool it. Keep in mind at no point during the incident should you attempt to open up the battery to apply water to the inside.
It’s only conducted when we can do it through a vent or an opening created by the accident.
Cooling the battery is very simple. A long continuous stream of water applied to the case of the battery is the most effective way to reduce the temperature within the battery and limit thermal runaway.
The application of our hose stream should be placed on an area of the battery where heat is determined. We can determine where the battery is heated with our thermal imaging camera or visually watching the battery.
For areas where smoke and steam are venting from the battery that application of water should take place for an extended period of time and not be interrupted.
When to stop cooling of battery in an electric car fire incident?
Once we see visually that the battery has been cooled either determined by no more smoker steam coming off the battery or a clean reading with our thermal imaging camera we can stop our cooling efforts at this point.
Monitoring the battery again for smoker steam coming from the battery or with our thermal imaging camera for 45 minutes before we release the vehicle.
The second responder is appropriate if at any point during our waiting period we see any indication of heat buildup. Water should be again applied to the battery typically when interacting with a hybrid or BEV at a roadway incident.
We are going to take action to shut down the high voltage and isolate it to the battery. We do this through the first responder cut loops or the high voltage disconnects within the vehicle. We also disconnect the 12-volt battery and often turn off the ignition.
To perform this operation with high voltage vehicle firefighting that operation remains the same although you may not be able to access some of these components due to the damage created by the fire. We are going to use any system that’s still intact to perform that operation.
But keep in mind it may not be possible due to the fire damage to the vehicle in most situations. The vehicle will have performed this operation on its own due to the high voltage relays in the battery this means that we can operate as if we’re at a conventional vehicle with the exception of interacting with those high voltage components.
Case study – Tesla Model S firefight training
Let’s take a look at Tesla Model-S training and research burn conducted in March of 2019.
Heat the vehicle battery
A 400,000 BTU (British Thermal Unit) torch was directed through an opening in the battery and over 3,000 degrees was applied directly on a module. The torch was left in place until the fire had spread beyond the battery into the front trunk and wheel well of the vehicle.
This took approximately 13 minutes. In this test, the heat applied resulted in thermal runaway to two modules.
Extinguish the fire
Firefighters were then directed to extinguish the fire and cool the battery. Knockdown was found to be a simple operation and the crew was directed to lift the vehicle in order to direct the hose streams at the floor pan battery.
At this point, the battery was checked with a Scott thermal imaging camera. Cooling operations began and water was directed at the hottest area of the battery for nearly ten minutes.
The battery case was then checked again after the cooling operation had been stopped for five minutes. This time was given to allow any potential heat to transfer from the cells of the battery onto the battery case. The battery case was found to be over 200 degrees Fahrenheit and cooling operations began again.
Cooling continued for another eight minutes until the battery was found to be sufficiently cooled. The vehicle was monitored for forty-five minutes and no signs of thermal runaway were detected.
The entire operation used approximately 4000 gallons of water and the vehicle did not react at any point after the testing. Once the battery temperature has been reduced to approximately the outside ambient temperature and that temperature has been maintained without the application of water again for 45 minutes we’re ready to release the vehicle.
To second responders including law enforcement and tell, it’s our responsibility to help educate our second responders on the proper storage and transport of the vehicle.
The vehicle should be kept 50 feet away from any exposures wherever it’s being stored. This is because there’s always a chance of re-ignition days or hours after the incident.
In addition, we can request that our second responders prop the vehicle up and position it in a way where any water that has gathered inside the battery drains out of one of the openings.
In this short video, they covered the various operational considerations and tactics required to effectively and efficiently mitigate fires at vehicles equipped with high voltage batteries.
The process for extinguishing a high voltage vehicle fire is no more challenging than that of a typical conventional vehicle.
Remember to establish your water supply early and expect a longer commitment time.
Cooling the battery directly with water is the appropriate extinguishing agent.
List of some electric car fire incidents happened
A list of electric car fire incidents happened all over the world is listed by Wikiwand.
Conclusion
Electric cars are increasing in the automotive market day by day. EV fire incidents are also increases. An electric car fire is a little different than an IC engine vehicle fire.
Electric car battery catches fire due to accidents, short circuits, etc. The measures to extinguish electric car fire is explained in this article.
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Key points
- Chances of EV fire incidents increases as the number of electric cars increases
- High voltage battery is the main source and main reason for the fire
- Manufacturers seriously implement the maximum possible safety for the passengers form EV fire
- The method to extinguish gasoline car fire ane electric car fire is different
- Cooling the battery directly with water is the appropriate extinguishing agent
