Extinguishing electric vehicle (EV) fires is challenging due to the thermal runaway that happens when a Lithium-ion battery cell short circuits and heats up uncontrollably, creating a self-sustaining fire through chemical reactions. Emergency responders dealing with EV fire directly are exposed to risks less commonly present during a fire involving a normal internal combustion vehicle.
Exposure to toxic flammable gas
An EV fire produces toxic gases from the combustion of plastic and metals and flammable vapor clouds from the combustion of Lithium-ion battery cells, consisting of hydrocarbons such as hydrogen fluoride, hydrogen chloride, and droplets of organic solvents. Oxygen in the air can mix with these white vapor clouds to fuel the fire, potentially causing an explosion without warning.
Burn from jet-like flames
Although EV fires burn at 815-1000°C, temperatures similar to an internal combustion vehicle, the venting of flammable gases from the EV battery cells causes highly directional flames that shoot outwards and burn intensely for an extended period. These flames are difficult to ease.
Electrocution from high-voltage direct current (HVDC)
Lead-acid batteries used in internal combustion vehicles typically have a voltage of 12V. However, the voltage of an EV battery pack ranges between 350V and 800V. This very high voltage battery, along with cables and components poses a risk of electrocution through direction current.
Even if the EV fire has been extinguished, the battery cells can still contain stranded energy that can electrocute upon contact without proper personal protective equipment (PPE).
Burn from reignition of the EV fire
An EV fire can reignite hours, days, or weeks later until the batteries are completely burnt off. Hence, the reignition can happen while the EV is still on scene, during transportation, or in storage. Continuous monitoring of the burnt vehicle should be carried out while ensuring there is a safe distance between the vehicle and the surroundings.
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Knowing these risks helps emergency responders make sufficient preparations to prevent and minimize harm when fighting EV fires. Emergency responders should prioritize their safety when handling an incident and be vigilant toward the unknown. With limited resources for fighting EV fires in Malaysia, emergency responders can learn more about EV fires from trustworthy sources such as EV FireSafe and NFPA.
