Professor Paul Christensen from the University of Newcastle is an expert in the field of EV fires and explained to Air Quality News: āLithium-ion batteries are amazing, and the reason theyāre amazing is because they can store a huge amount of energy in a very small space.
āBut naturally, that energy will try and get out.
āIf the battery is exposed to excessive heat, or there is a penetration in the battery case, then you get an internal short circuit.
āThis short circuit causes what is called Joule heating, this is when the electricity passing through causes heat and you cannot get rid of the heat as fast as you are generating it.
āThen because of this heat, a chemical reaction takes place which generates more heat, which then causes the chemical reaction to go even faster, and as you can see itās a vicious cycle.
This is a process called thermal runaway and it can lead to ignition, or in some cases even explosion.ā
The obvious choice seems to be to extinguish the fire, however many EV manufacturers actually advise for a controlled burn. This is where the fire services allow the vehicle to burn out while they focus on protecting the surrounding area.
Once the fire has been successfully put out, the problem for the fire brigade is not over.
Electric vehicle fires are known to reignite hours, days or even weeks after the initial event, and they can do so many times.
Not only does this pose a safety issue, but it also poses a legal issue: recovery firms are increasingly concerned about dealing with electric vehicles.