02.2 What we know (so far)
Here's what our research found & what we learned from the experts*
There's a lot yet to be discovered regarding electric vehicle lithium traction battery fires - referred to here as 'traction battery fires' - but we've collated a list of the facts we think it's important for emergency responders to know now.
Electric vehicles are less likely to catch fire than ICE vehicles
Studies are ongoing, but evidence suggests a traction battery is less likely to ignite than ICE vehicles.
Thermal runaway is how all EV battery fires start
When a battery cell experiences a short circuit, thermal runaway may occur.
A battery under 50% charged is less likely to ignite
Testing shows that a traction battery with a state of charge (SoC) of under 50% is less likely to ignite.
An EV lithium traction battery burns hotter than an ICE vehicle
A burning ICE car may reach 815 degrees celsius, an EV up to 2760 degrees celsius.
Fire behaviour is different & presents new challenges
Recognising an EV by vapour & fire behaviour assists in early identification & management of the incident.
It's not smoke, it's a vapour cloud of highly flammable gases
When thermal runaway occurs, large clouds of flammable gases are released, primarily hydrogen.
Water is the most effective way to extinguish an EV battery fire
Lots of water to cool the battery & suppress flames is required; at least 4000 litres should be established.
EV traction battery fires may require more resources
A longer suppression time may mean additional people, appliances & water.
The location of an EV battery makes fire harder to extinguish
A traction battery, located along floor pan, means the vehicle may need to be jacked up to apply water.
Risk of electrocution via water stream is lower than expected
An EV is not earthed, presenting low risk when using an unbroken stream of water to suppress fire.
Electrocution risk from HV cables is lower than expected
Orange cabling & components indicate high voltages, from 400V, & can pose a risk if damaged or exposed.
A submerged EV does not electrify a body of water
An electric vehicle underwater does not cause surrounding water to become electrically live.
Best practice; allow a traction battery to burn out
If location & time allow, there is a lower risk to all responders in letting the battery completely burn.
EV traction battery fires can reignite, hours or days later
If it's not possible to allow the traction battery to 'burn out', re-ignition risk should be considered.
*We're incredibly grateful to the many helpful (& patient) people & organisations who have supplied information & peer reviewed this online knowledge hub. You can find a list of awesome humans on our Team & Supporters page.