ELI5- Are lithium batteries in electric cars more dangerous or hazardous than a gasoline car? If so, why or why not?
In: 944
Yes. Gasoline evaporates pretty quickly when it gets wet. Batteries light on fire and don’t stop lighting on fire.
Initial evidence from a study a few years ago says not.
[https://www-esv.nhtsa.dot.gov/proceedings/24/files/24ESV-000210.PDF](https://www-esv.nhtsa.dot.gov/proceedings/24/files/24ESV-000210.PDF)
The IIHS (insurance companies) also report better results with EVs
[https://www.iihs.org/news/detail/with-more-electric-vehicles-comes-more-proof-of-safety](https://www.iihs.org/news/detail/with-more-electric-vehicles-comes-more-proof-of-safety)
But there are those who are opposed to EVs that will deny facts and push their theories of how EVs are more dangerous.
EDIT: To be clear though, there are reports that they are subject to more claims and accidents. (and much more expensive to repair)
[https://cleantechnica.com/2019/08/26/high-performance-electric-cars-have-higher-accident-rates-finds-axa/](https://cleantechnica.com/2019/08/26/high-performance-electric-cars-have-higher-accident-rates-finds-axa/)
But if you’re talking “more dangerous” in the sense of fatalities and injuries, then the answer is likely no.
In normal use, about the same.
If a fire occurs, for whatever reason, then Lithium batteries are way more hazardous as they not only take massive amounts of water to put out, the fumes are also highly toxic.
Fire personnel now have specific plans for dealing with electric car firescrashes.
Gasoline cars have a substantially greater risk of fire than typical EV batteries, risk of fuel spreading out from the source, and a risk of explosion. But Gasoline fires are MUCH easier to put out than a typical lithium battery, and they tend to have less toxic fumes (the gasoline, anyway, the rubber, plastic, and other materials in the car give off very toxic smoke when they burn). Lithium EV batteries don’t have a risk of explosion, but if they rupture, the damaged portion of the battery can become very hot very quickly and they can be very difficult to stop the fire.
There’s a less common type of EV battery that doesn’t rapidly heat or easily catch fire: lithium ferrophosphate (LFP) batteries. They don’t store as much energy per kilogram of battery, but if you pierce the battery with a piece of metal or rupture it, it won’t catch fire like the others can. As far as I know, the only EVs sold in the US that use LFP batteries are the Tesla Model 3 SR (after October 2021).
Lithium battery powered cars are probably safer but it’s kind of an unfair comparison.
1. Yes, a lithium battery fire is much harder to put out than a gas fire. But a lot of effort and decades upon decades of engineering has gone into making sure car gas tanks are safe. Lithium batteries for cars are still in their early years and we can expect that in twenty, thirty, fifty, years lithium battery engineers will look back on what we do today and shudder at how dangerous it was. So you’re comparing a mature technology to a new one.
2. We’re ignoring other dangers of gas cars. There are plenty of people who asphyxiated from gas fumes (intentionally or accidentally) and I don’t think it is entirely fair to limit our examination to just the “will it burst into flames” risk.
3. We’re ignoring other parts of the distribution system. A few months back I was down in Florida and someone crashed into a gas station. Innocent bystandard, just fuelling up their car, ended up burned to death. Electric charging is significantly safer for everyone than the dangers of transporting and storing massive quantities of flammable fuel.
So, if you’re driving down the road, today, in a fully charged electric car and crash, then compare the risks of the same accident with a gas powered vehicle, it could well be that the electric car is a bit more dangerous. But if you look at total risks, then electric is better. If you want to ask conceptually which is safer, then electric wins again.
You can’t really compare hazards like that.
Gasoline is much more dangerous during normal operation, because gasoline normally ends up burnt, spewed into the air, and replaced. Gasoline combustion products are major pollutants. They cause respiratory disease near the car, and they warm the entire planet.
Meanwhile, the lithium in a lithium battery doesn’t actually go anywhere. The energy comes from electricity, which can be generated far away from anyone who has to breathe the fumes from the power plant. And, power plants (if they burn stuff at all) are often more efficient than car engines, which means less warming of the planet.
But, lithium batteries are more dangerous in a crash. The energy in a lithium battery is enough to utterly destroy the battery if it should find a short-circuit, such as one created very easily in a crash. Once the battery is shorted, all it takes is one hole to let air in, and it’s on fire. And once lit, lithium is near-impossible to put out, because it’ll burn in anything – air, nitrogen, water, whatever.
Gasoline tanks have no such natural fire-starter. Gasoline only gets hot when it’s on fire, which only happens when it’s mixed with air. There isn’t usually enough air in the gas tank to be dangerous. And it’s really hard for a crash to mix the gas tank with air AND heat part of it to ignition at the same time. And, gasoline is much easier to put out, since just throwing water at it will eventually work just fine.
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they store kinda comparable amounts of energy, though a full gas tank probably has somewhat more. Gas can spill and spread more, but lithium batteries are harder to extinguish once they’re burning.
Hard to compare risks like that, but from a pure amount of energy point of view, gasoline cars have more energy stored and might be more dangerous for that reason.
Gasoline has an energy density of 46 MJ/kg. 10 gallons (US) of gas is 60lbs, or 27kg. So a typical to smallish tank of gas in a car would have 1,242 MJ of energy in it.
A bigger EV might have an 100kWh battery, which is 360MJ of energy.
From the standpoint of conservation of energy, if the absolute worst happens and all that energy is released at once, the gas tank would be more bad.
(this is why also why a gas car can usually drive more miles on one tank than an EV can drive on one charge)
On average there are 1529 fires per 100,000 gas vehicles and just 25 fires per 100,000 electric vehicles.
I am a firefighter, we have had to look at EV’s in detail not because they are catching fire at a greater rate, but because of the risks to fire crew on scene and the difficulty in keeping an EV extinguished. There are special storage and space considerations for an EV once it reaches a yard for insurance inspection and eventual scrapping too. An EV fire is toxic as hell (not that a gasoline fire is a delight either of course).
We have to know and understand that if an EV catches fire in a rural or remote location, then it is likely that we will not have access to sufficient water for cooling/extinguishing. We can call for ‘make tankers x ‘ to have a shuttle system in place for deliveries of water in 6 ton loads, but at any typical motor vehicle accident you find yourself trying to manoeuvre in 14 ton tanker vehicles in a traffic jammed, restricted location and it becomes a serious hassle.
In short, it appears that EV’s are vastly less likely to catch fire, but when they do it’s a pain in the arse. It’s worth noting that EV’s as modern high-tech vehicles have so many safety features too (compared to 100 years of gasoline vehicles) which would help with the incidence of accidents.
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