The truth about electric car fires

If you believe the media sometimes you'd think that the slightest accident in an EV would turn into a fireball or people shouldn't park an EV next to your home for fear of spontaneous combustion. Well, it's time to take a deep dive into the furore around electric car fires.

How likely is an electric car to catch fire compared to a petrol/gas powered car. What does it take to get a lithium battery to ignite, and what happens if you hit one with a big lump hammer, multiple times?

Watch this video to find out.

For further reading on the subject here's a few good links for you.

[mraidymaddful]

To be honest Richard, I was expecting you to pierce the battery with a screwdriver. I have seen car crashes and vehicle burn outs on You Tube where the battery was pierced in a crash and it flared up and totally killed the car.
Then there are the ones where the vehicles just suddenly burst into flames in the middle of a charge cycle. Apparently it's quite common in China.

[JohnnyEars]

I was expecting you to puncture the battery or short it out (which could well happen in a severe crash), this would have yielded different results.

[USUG]

curiously, according to those statistics, hybrids are twice as likely than gas cars to catch fire.

BTW, should have pierced the battery, and also overcharge the hell out of it

[dkd]

A fundamental difference with electric cars is that all the reactants to make things happen are present in the charged batteries. This is not the case with petrol, as you must mix an oxidizer (usually from the air) in order to make things happen.

[criscross]

What about a dead short on a 400v battery pack in an accident replicate that.

[gnki]

It's not the burning process that's the problem, but actually putting out the fire. Petroleum fires are no biggie to extinguish, but fires involving multiple battery cells can last for hours and are tough to put out. This is especially true for lithium-ion batteries that are found in electric cars. They can release tons of heat and toxic fumes, and can even start back up after being put out. So, special techniques and gear may be needed to safely extinguish battery fires. It's a bit of a challenge, and the industry is still figuring out the best ways to deal with it.

[robjoenz]

Setting one battery on fire does not fully explain what happens, being that the original Teslas had 1200 of those in the battery pack. Hitting the battery with the hammer would not throw the battery into a thermal runaway, it would cause the crimp on top to give way and allow the battery to vent. Piercing said battery with metal would cause the desired (or undesired) effect for your demonstration. As far as the petrol fires being more frequent than the battery you are correct. However, ask a fireman which fire he would want to attempt to extinguish, and I believe he would say petrol every time.

[Paul-lihq]

Here's a fascinating, slightly related story for you....
I dropped my vape into water last week... Grabbed it out quickly, hoping it would be ok...
It wasn't!!! The water had obviously shorted out the battery/internals and the heating coil came on. And STAYED ON. Obviously, the vape started to get quite hot to the touch..! Not knowing quite what to do about this, I decided to sink it back in a tub of water - hoping at least to cool it down! This did appear to stop the coil from heating, as the blue light at the bottom went out and it was no longer hot to the touch...

But here is the kicker... I remove the vape from water a day later, to dispose of it... And the blue light came on and it started heating up CONTINUOUSLY again. This nonsense went on for days.

I do not recommend anyone try to recreate this at home!!!

[julianpritchard]

As I’m sure someone will remember, back in the day, and I think it was William Woodard on top gear ( yes I’m that old) demonstrated that a large percentage of car fire were actually, the brake fluid hitting the hot exhaust manifold that caused the fire, not petrol.
If batteries blew up when dropped I’d have shares in Dewalt by now given the number of times I’ve dropped my drills and drivers .
I believe the the German fire service drop an EV in a modified skip or shipping container filled with water for about a week after a fire, just to be sure it’s safe.

[mikedx]

I don't think it's question of which type of vehicle catches fire easiest, but which type of vehicle fire the local fire departments can actually extinguish versus will the vehicle have to just burn itself out. Gasoline fires can be rather easily extinguished these days by anyone's fire department. EV fires, on the other hand, almost always have to be allowed to simply burn themselves out while the fire department stands around watching the EV burn and simply trying to prevent the EV fire from spreading to other combustible materials in the vicinity.

[Roo]

Tried putting the battery in water? During the floods in Florida (last year?), the EV's were exploding 10 to the dozen. Thanks for the impact demo :)

[andrewallen]

The truth is that once an electric car catches fire it cannot be put out by professional fire departments and may catch fire again up to two weeks later. When my petrol car caught fire I was able to put it out with my fire extinguisher!
Most people don't realise it was safer to be on the Hindenburg when it caught fire than a Boeing 737 MAX with a single faulty AOA sensor!

[BaronSamedi]

Do you know what is the major cause of fire in any car (EV and ICE)? It is arson, deliberate or accidental. Dropping a cigarette on the upholstery and such. Actually, there is about three times as much energy in your car's upholstery than in its fuel tank or battery.

[jerkins]

You could try attacking the 18650 with a hatchet, rather than with a lump hammer...

[scraverX]

I will say I was wondering how many hits the 18650 would take before "something" happened. I've seen one run over by a HGV, and sure it was pretty squished but like your test it was just one cell in isolation. Gets a little more complicated when you have multiples.

[PaulM]

Some Western YouTube vloggers are reporting a lot of fires in Chinese-made EV's, in China. Seems those cars are not tested and built to the same standards of safety as the Western built EV's....

[maxtorque]

Some important points to add ime:

1) the no1 cause of vehicle fires are firse as a result of the act of arson, not from a fault with the vehicle or a crash!
2) The second largest cause is hot exhaust systems setting fire to dry scrub and grass on which the vehicle has been driven / parked
3) the third largest cause is sparks from hot exhausts settting fire to dry scrub and grass

Clear the electric vehicle that operates at close to ambient temperature cannot cause fires by mechanism 2 or 3 so is immediately massively less likely to cause a fire in the real world


The no1 cause of vehicle fires for internal combustion engined cars after a crash or impact is nothing to do with the fuel it runs on, but is actually as a result of hot engine oil, power steering (and transmission lubes) or in fact brake fluid being split onto hot exhaust systems and reaching there flash point. Again, without a hot component to start that fire, and with vastly less lubecants one board (and those that are on board being at far lower operating temps) again the eletric vehicle has significant immunity to these causes

The no 1 cause of electric vehicle fires however is not actually to do with the vehicel directly, but is poorly specified, maintained or incorrectly used charging infrastructure! Because a BEV can sit charging for a long time, an electrical circuit in the supply to that vehicles charging equipment can result in a fire. For EV owners this is by far the greatest risk!

[vintagemachines]

Good video. You should do a video explaining what happens when an electric car is flooded by saltwater, and that weeks later the car may be operational, but still a danger to ignite...

[vwbeetle]

I am all for electric classic car conversion but as a lot of commenters have mentioned, this video doesn’t really address the root cause of lithium battery fires and also the issue of putting the lithium fire 🔥 out. The Author should address this in relation to a converted classic car tucked away in my garage beneath me charging while I sleep. The risks and what we can do to mitigate (so I can sleep 🛌 soundly 😅)

[wombatbreath]

What was missing was a centre punch to ensure that the battery casing was punctured - that would have been more dramatic. However, the experiment was valid to simulate an EV crashing. (Disclosure: I drive a Kona EV)