Understanding how electric vehicle (EV) fires start is key to understanding how best to tackle an EV fire. And, whilst EVs don’t catch fire as often as petrol or diesel vehicles, when they do, they can be very difficult to extinguish and can cause devastating collateral damage to surrounding vehicles, property and people.

Understanding how
Every electric vehicle on the road today is fitted with a set of lithium-ion batteries. It’s these battery packs that are the fuel source for the EV. They provide a much higher energy density than other batteries, so if an EV does catch fire, it can burn for many hours, even days. Fact: a lithium-ion battery can deliver up to 150 watt-hours of energy per kilogram. A traditional wet cell lead battery delivers just 25 watt-hours of energy per kilogram in comparison.

It is also widely recognised that lithium-ion batteries are not easy to keep cool. A traditional automotive lead acid battery will cool down relatively quickly after the engine is switch off. A lithium-ion EV car battery will, however, still be able to generate enough heat to start a fire a full 24 hours after the ignition is turned off.

So, it’s fair to state that lithium-ion batteries not only behave differently to regular automotive batteries, but they also have the potential to be much more volatile. And herein lies the explanation to how EV fires start.

A defective or damaged battery = the most common cause of an EV fire
The most common form of fire in electric and hybrid vehicles is either a damaged high energy battery or a manufacturing fault that creates a short circuit. The problem is, it’s not easy to identify if a battery is defective once it is installed and leaves the manufacturing facility. Likewise, since an EV’s battery pack is located underneath the car, it is possible it could sustain damage without the driver’s knowledge. And, due to their prolonged energy capacity, once a lithium-ion battery does ignite it can be very problematic to put out and, worryingly, it also has the potential to reignite.

Tips and advice
As experts in health and safety when working with electric vehicles, here at Prosol UK we have a few expert tips to share when it comes to being alert to any dangers; after all prevention is better than cure!

It may seem obvious, but if there is smoke coming from any part of an EV, there will be fire. Likewise, if the EV’s oil or fuel levels suddenly drop or engine temperature increases rapidly, there could be an underlying issue. Watch out for the battery failing to hold its charge or draining faster than previously too, this could be a sign of battery damage or defect. What’s more, if a manufacturer announces a recall for a defective EV car part or system, make sure the vehicle is booked in and rectified as soon as possible.

If any EV you drive displays any of these characteristics it is imperative that it is checked as a matter of urgency by a professional EV mechanic or technician. Don’t hesitate to get specialist advice and play your role in preventing an EV fire before it starts.