Although battery fires in electric cars and two-wheeled vehicles are not a common phenomenon, they are notoriously hard to put out, requiring special training and equipment by firefighters. Although the full scope of the issue is part of a contentious debate, [Aarian Marshall] over at Wired recently wrote an article about how the electric car industry has a plan to make a purportedly minor issue even less of an issue. Here the questions seem to be mostly about what the true statistics are for battery fires and what can be done about the primary issue with batteries: thermal runaway.
While the Wired article references a study by a car insurance company about the incidence of car fires by fuel type (gas, hybrid, electric), its cited sources are dubious as the NTSB nor NHTSA collect statistics on these fires. The NFPA does, but this only gets you up to 2018, and they note that the data gathering here is spotty. Better data is found from European sources, which makes clear that battery electric vehicles (BEVs) catch fire less often than gasoline cars at 25 per 100,000 cars sold vs 1529/100k for ICE cars, but when BEVs do burn it’s most often (60%) from thermal runaway, which can be due to factors like a short circuit in a cell, overcharging and high ambient temperatures (including from arson or after-effects of a car crash).
As for the claimed ways to make battery-powered vehicles safer, the Wired article mentions the shift to more stable lithium-ion chemistries like lithium-ion phosphate (LiFePO4, or LFP for short), experimenting with solid-state batteries and easier ways to extinguish a fire and disconnect the BEV’s battery, along with firefighter training. Meanwhile the European Union will require a ‘battery passport’ starting in 2027 which tracks the origin, manufacturing and testing of batteries.
Of the risks with batteries, thermal runaway is probably the least predictable, with a review article by [Mahn-Kien Tran] and colleagues in Processes from 2022 covering our current understanding here, including ways to model and predict the occurrence of thermal runaway to increase safety while e.g. charging a battery. As internal shorts due to wear and/or manufacturing defects can be hard to predict, it is essential to detect thermal runaway before it has a chance to get out of hand.
Beyond electric cars, electric bikes are far more notorious for catching on fire, with these devices in New York City having gained the reputation of burning down apartment buildings, generally while charging. As MIT Technology Review reports, a solution here may have been found in battery swapping stations that are equipped with sensors and fire extinguishing systems, so that delivery drivers and other e-bike users do not have to charge batteries at their apartments while praying that they don’t wake up to thick smoke and a screaming fire alarm.
As battery-powered vehicles and devices become more and more common, it’s clear that even if the risk of fire from these vehicles is small compared to their gasoline-powered brethren, those generally do not catch on fire while parked in one’s garage or hallway. Finding ways to mitigate this risk is therefore more than welcome.
the difference between cars and electric bikes is that cars have to pass safety regulations to be sold, where electric bikes are made by anyone, to any random design, and may or may not even been tested – and might have the cheapest charging circuit and battery they could find.. So yes, they catch fire a lot…
Do you really trust those chinisium batteries that much? Yeah, passing regulations is one thing, keeping quality solid is another.
Where does one get a NOT chineseium battery quickly and cheaply? I have battleborne just down the street, but they don’t make small portables
this is an example of where social phenomena come into a technical problem as well. electric cars are relatively less likely to be stolen / more likely to be recovered or compensated, relatively more likely to be a status symbol, and relatively more of a known quantity before purchase. so people are likely to spend a lot of money on an electric car and view it as an investment.
on the other hand, electric bikes are relatively common to steal, relatively more likely to be simple utilitarian transport for relatively impoverished people, and relatively unknown. so people buy them on a lark (uncertain if it’ll be useful at all), or they buy them just to fill a need. they are much more price-conscious. and on top of that, a lot of brands are making “me too” electric bikes for fashion / PR reasons, without really advancing the state of the art of engineering them. as a result, cheapest / crappiest remains at the forefront of the electric bike market.
just a weird case where something totally non-technical like “police care about a stolen Tesla, do not care about a stolen Tern GSD” comes to have material effects that engineers are then asked to try to solve.
Electric bikes aren’t really that great value in the end. A typical commuter distance on a bicycle is about 5 km, so 10 km round trip. 5 days a week, 52 weeks a year makes it 520 km a year. The lifespan of the bike is about 10 years, so 5200 km total. If the cost of the bike is €1000 then it’s 19 cents a km.
Even with European fuel costs, let’s say €1.8 a liter and 6 liters per 100 km, that makes it 11 cents a km, which is significantly less. For anyone who also needs to own a car to get around further than 5 km from the house, in all weather, trying to save money with an e-bike just doesn’t work. Your daily commute must be more than 20 km to justify the e-bike, but then your commute time becomes longer and you begin to suffer the elements trying to ride all year round.
A regular cheap city bike costs a couple hundred euros, so that’s real value – that can save you money. I calculated that the maximum price I could pay for a bike would be around €800 – and that’s pretty much the bottom range for e-bikes. I don’t see how e-bikes would be a sensible option for the “relatively impoverished” unless it’s really their only mode of personal transport.
Wait, I forgot to multiply by 5 in the first part. That means e-bikes start to make sense past 4-5 km daily commute – depending on how fancy a bike you want to buy.
Mine is just under that limit, so it doesn’t.
You think your getting 10 years out of a cheap e-bike?
Unstolen for 10 years (if it was good)?
Also England. Weather prohibitive 300 days/year. Lunatics driving on wrong side of road. Minimum blood alcohol for driving laws.
No. If you have to keep it outside on a bike rack, it’s 2-3 years max before ice and water breaks in and destroys the battery socket. It’s difficult enough to keep the gear of a regular bike operating under those conditions.
The decision to use an e-bike is often based on factors other than cost.
The time and convenience to travel are important factors.
The decision to use a car also includes more factors than the cost of fuel.
Parking, traffic, insurance, taxes, and maintenance are but to name a few.
Of course, one must also consider both the landscape (hilly or flat?), the
typical destinations, the safety, the likelihood of theft or vandalism, and
the availability of other alternative means of transport as well.
I feel like you’re forgetting about insurance, parking and maintenance costs in this equation. I’m not even confident that will tip the scales in ebikes favor, but it might make the gap a little smaller.
If you already have to have the car anyways, those don’t count because they’re inevitable regardless of whether you also own an e-bike.
Also, if you ride the bike and let the car sit on the parking lot with little use, you’ll get issues and extra maintenance costs with batteries running flat and brakes rusting, and tires going square from static compression. Moving it a few km every day keeps the bearings and seals in better condition.
Police don’t care about a stolen car of any kind unless it has electronic tracking that will lead them right to it. Then maybe, if you call them and tell them ur looking right at it, maybe.
Tell them your carrying and they will be right their to protect the thief.
Their job is filling out a police report for the insurance company. That is all.
That and beating your ass for cardio.
One of our local EV charging stations has been down for nearly a month after an EV caught fire while charging. It’s a real – if (hopefully!) rare one.
Before anyone tries to claim I’m anti-EV, I’m an EV owner. Unfortunately, the station that was taken out has 8 chargers, leaving me with a 3-charger station as my only realistic local option, so it’s pretty inconvenient. At least no one was hurt in the fire – the owners were shopping while their car charged.
Worth pointing out that if there is ever a fire at the petrol station it can take a long time to repair and reopen as well. That ongoing inconvenience to everyone after an accident isn’t unique.
In the case of petrol and diesel right now you probably have more ‘local’ options as its the more established system, so you’d expect more minor inconvenience. But if you don’t you are even more in trouble than the electric car would be, as those can be charged even if its so slow it takes all night with a long extension cord and your normal household electric.
Fast charging stations cost a lot of money to build in the first place vs. regular old tank in the ground and a fuel pump. A single pump is about $20k investment, whereas a fast DC charger can range from $45-100k. That’s the main reason you don’t see them everywhere.
And you wouldn’t be in much of a trouble if you don’t find a service station and you run out of petrol – you just call the AA and they’ll bring you fuel, because you can do that with liquids: carry them in a canister.
A single pump would never be built.
A large cluster of pumps might come out to $20k/pump.
Until the tank leaks.
In the USA, there are former gas stations all over the nation for sale.
You buy them, you bought the cleanup bill, nobody that stupid.
They would, but in those cases the tank is typically above-ground to save on installation cost.
The same thing applies for EV chargers. A single outlet may cost $100k while the grid connection and the field wiring and installation cost will be another $100k so it’s not efficient to have just one.
On another site, someone posted picture of an EV on fire in a parking lot of a store he was at. Hopefully no one parks these in garages, but keep them out on the street. I use these batteries in model airplanes and know how bad these fires can be (and they are ‘small’ batteries in comparison).
Have you seen a petrol fire?
Flight batteries are engineered to be cheap, high-capacity, and as light as possible, not to be safe. An EV battery has a completely different set of design criteria, and to claim that the risks are comparable is to be wrong or to be disingenuous.
It’s not as bad, but EV batteries and the companies that use them are no saints.
Tesla for instance wanted to use NMC cells for their added robustness, but still uses NCA which is prone to thermal runaway, because it’s got greater energy density and costs less. To combat the fire issues, they encase the cells in heat expanding foam, which is supposed to isolate failing cells, but with a big enough fault it’s not really adequate.
I’d say “that’s capitalism for you”, but it’s also just a reminder that there’s no perfect solution that maximises every desirable trait. You always have to compromise.
Do you use automotive grade cells (Panasonic, Samsung), off-brand cells of the same style, miscellaneous mobile-device pouches, or rc-marketed pouch cells?
Which is still biased information, because of the heavy bias towards new electric vehicles vs. cars of all ages on the roads. With the rapid growth in the market, the vast majority of EVs on the roads are only few years old, and new cars break down less than all cars.
The criticism around 2009-10 when these issues were first getting raised was that EVs could not get the promised range improvements despite battery technology improving rapidly. It was known that larger batteries were a fire hazard waiting to happen, and increasing energy density would make it worse, so the support and isolation structures necessary for preventing and protecting against thermal runaway would eat up the gains in battery energy density. The industry – mostly Tesla, as others were more conservative about the matter – chose to ignore the warnings and put in bigger and denser batteries using chemistries that were prone to fire without adequate shielding to save on mass. The end result was cars that light up in seconds following a crash and trap the passengers before help can arrive, and burn down parking garages and other buildings because they’re so difficult to put out once on fire.
The age of the vehicle is not a huge factor in them catching fire or not, as most vehicle fires for any energy source are because of accidents and inadequate maintenance/repair – which can happen to almost any age of vehicle, or sometimes active design flaws. Also all the studies I’ve read are only ever comparing the EV be it more luxury Tesla’s or town car Leaf’s to the comparable age and usage fossil fuel cars, not all cars ever made.
So while its true that age makes it more likely this particular vehicle is an accident waiting to happen that is about a great deal more than just its age. I’d tentatively suggest its rather more likely because the folks buying and running older cars tend to be too poor to really maintain them properly. You don’t hear or see many of the more classic valuable old cars burning. So I’d suggest with EV that is going to be a self damping feedback loop – too poor to maintain the car as the battery ages means you don’t actually have a useable car that actually goes anywhere – can’t cheaply and jankily bodge them the way you can for most of the more perishable parts of an ICE power train.
Not true. Newer vehicles are driven by a different population of people and are generally in better shape and equipped better for collision avoidance, lane keeping etc., and newer vehicles haven’t yet had the time to run into disrepair.
Think about it: people who can afford EVs are mostly middle class or greater and middle-aged or older, since nobody else can afford to plonk that much money on a new car. Working class people and the more risk-prone young drivers simply don’t buy them.
If you’re in the demographic to buy an EV, you’re not likely to drive it like you stole it – hence the lower accident rates.
Then there’s an entire other thing about what counts as a vehicle fire or what is reported as a vehicle fire.
Recently in the news I read about a van that caught fire on the highway. The catalytic converter was completely corroded, blocked, and exploded, setting fire to the underside of the van. A passerby put it out with a handheld fire extinguisher. Small fires like that happen often, with something like an electrical fault or an oil leak making smoke under the hood – nothing very dramatic happens – but the insurance claim says “vehicle fire”.
Comparing these cases to EV battery fires is a bit apples to oranges.
The only vehicle fire I’ve ever seen (other than on a racetrack) is a Ford escape <5 years old. Sample size of 1, but ¯_(ツ)_/¯
In the past 3 years I’ve seen 2 petrol based vehicle fires.
One I arrived at when it was just smoke coming out from under the hood. But by the time I found the fire extinguisher in my car, the front of that car was engulfed in flames. I keep it more available now.
I knew a guy who wanted to do his own wiring for the radio. He used all red wires and forgot which was which, so he connected battery plus and ground together, filling the car up with smoke when the turned the ignition.
His main mistake was no fuse.
I’ve seen similar. Color coded wire didn’t help.
The other mistake was using the wrong gauge of wire – too thin – so the fuse would not have helped; but that’s what kept it from becoming a total loss. The wire only got smoking hot and not flaming hot.
Fire risk increases dramatically with age, and many EV’s don’t have a high age yet.
The Mercedes Citaro bus has a design flaw which (according to our workshop manager) “guarantees a fire after 8 to 12 years”, to such an extent that in Roma (250 bus fires in 5 years) these buses are nicknamed “Flam’bus” [https://www.agi.it/cronaca/news/2021-10-05/misterioso-fenomeno-flambus-roma-bus-bruciati-14080752/]. The culprit: A diesel line for the heater being hung such that it will chafe through with vibration, then spray diesel over exhaust parts.
Ironically, a very similar fault has burnt down at leas one and possibly two electric! buses (with a diesel heater) in the Netherlands.
I wonder what will happen to high voltage lines after years of vehicular vibration and possibly road salts and moisture ingress. I expect non-battery fires will rise with EV’s as the fleet grows older.
Just drive a diesel. Bio, synthetic or fossil, no issues like gas cars or EVs.
Wasn’t it a diesel Range Rover that started the fire that burned down a Luton airport carpark? Turns out diesel does ignite if it’s sprayed onto a hot engine by a faulty fuel line.
It was indeed.
It also doesn’t help that modern fuel tanks are usually made of plastic, literally “adding fuel to the fire” when they inevitably melt in the conflagration.
It was a range rover.
The cheapest way out of that was the fire.
Sure car parks aren’t cheap, but compared to keeping a Chinese made English car running?
So here’s an interesting additional data point on how to make lithium ion battery packs safer: https://ntrs.nasa.gov/api/citations/20150020936/downloads/20150020936.pdf
I have to admit, I haven’t read the whole thing, as I was more interested in how much battery power a NASA EMU space suit has, but it looks like there’s some really interesting thought and design going into this problem. And, I have to admit that the idea of being in a space suit with an exploding lithium ion battery is a lot scarier than being in a car with an exploding lithium ion battery – even if one of those scenarios is inordinately more likely
You need a safe way to disable and fire-protect the parts of the electric battery in case there is fire (external or from an elemwnt of the battery). Disabling is to disconnect the battery in smaller parts to avoid short-circuit that will reignite the fire and dire-protect is to shield the remaining elements from the fire.
I suggest both to be done with expanding foam that contains both co2 (expansion) and h2o (termal protection).
Once a cell is in thermal runaway their is almost no stopping it.
Hold the whole pack together with low temp solder.
Include steam gen and cell launch tubes.
So the flaming cells are launched into neighboring lanes, through windows etc.
Enough e-cars and the system would go prompt critical!
Fun!
Battery packs would look like zoomy headers for a 2000 banger.
Regulations just pushes prices up and of course is a great business, since government take his share of the dough through it.
What will actually works out is the evolution of the technology coming around as the time goes, as it ever happened.
And sorry for you guys that trust so much in your regulators, I know all the discourse you guys have in response… We all need to trust something to feel safe, that’s ok.
I like EV’s. I have an EV moped (not Chinese cheap rubbish). So cheap to run. But what the world really needs is less cars. All cars catch fire, thermal run away is for fossil cars too. When I was a mechanic, most engine bay fires started after the car had an over heating problem. If only owner had got that fixed them may still have their car.
The real issue is big business always fights regulation and wants less of it. But it is this very regulation that protects the consumer from dangerous products.
What does make me laugh a little, is how many anti EV people that rant about EV fires sleep at night with their phone on charge next to them.
Not always. A lot of the regulation we have is big business lobbying for laws and rules that are designed to hurt their competitors more. It’s a feature of crony capitalism – corporations build up the regulatory environment to suit their business in particular, setting up thresholds and barriers for smaller competitors that they themselves can get around easily.
It’s a limited risk for batteries in the 5-10 Watt-hour category. I have mine on a metal table. I’m acutely aware of the risks and charge all my larger battery packs in a metal box.
Wrong li-ion type.
another aspect of this is that electric cars are too fast and their speed is too ungoverned. there was a famous incident in coral gables 2 years ago where a young man driving a tesla at about 90mph in a residential area hit a small bump on the road, went airborne, and crashed into a tree, resulting in a spectacular explosion. and then a few months ago almost the same exact crash happened in my small city! there’s no reason at all to make a car that can go 90mph outside of a freeway, but tesla did it anyways and the resulting spectacular crashes draw a lot of attention to exploding battery packs. doesn’t matter how safe they really are, the cameras will go where the young men are making novel boom-booms.
of course the same thing happens with gas cars but with the tesla it’s just a little easier to be that stupid, and a lot more exciting for the media.
If anything I’d have thought EVs have lower top speeds than ICE cars. When you have a single gear ratio and want to avoid cogging at low speeds you pick a ratio where the motor turns faster at low speed but tops out at 90 or 100mph. ICE already has gears so it’s trivial to add another and top out well above 100. 155mph is a common limited top speed.
The top speed of an electric motor isn’t really a hard limit – you simply start losing power as the motor coils begin to impede current flow past a certain speed. If you have enough voltage available at the battery/controller and your motor is way oversized, you can force it to go faster and faster until air drag exceeds the power you’re able to push into the motor.
There’s also certain types of DC motors without permanent magnets where the field coils are wound in parallel and series with the rotor coils. Wiring it wrong creates a motor that has no speed limit. It will intrinsically change the field current to increase speed indefinitely until the rotor explodes from centrifugal forces.
At above about 150 mph your typical car makes enough lift to impair steering.
That’s where you actually need/want ricer type addons.
You want a high gear ratio diff. For the launch. Lower top speed. More RPM at highway speed. But tire smoke must be served.
That is unless your English.
In the old days fast English cars were tuned for salt flats (and towing), American for 1/4 mile and German for Nurburgring.
These days they’re all tuned to extract maximum maintenance dollars.
But English cars are made in China.
That’s not a problem with electric cars. ICE cars can go fast too. That’s a problem with reckless drivers.
First: F the nannies. F the state ref. F CARB. V8s forever!
But e-cars are generally fast cars you have to drive slow.
Even the few that are truly slow enough you can drive the piss out of them aren’t fun.
Not a Honda 600N in the lot.
I’ll add that part of the problem is it’s really hard to get water on/into a burning EV battery. The battery packs are sealed, lack any reasonably sized voids/channels around them that allow water through, and are at the very bottom of the car. Best you can do is splash water on the bottom, or hope they burn through the floor pan and allow water to be applied from the top.
You can’t put out a lithium fire with water, anyway.
I’d guess that enough water could keep adjoining cells cool enough to limit the fire spreading.
That really seems like one way to attack the problem: how do you prevent a single cell on fire from spreading to all its neighbors? Perhaps a system could be designed to eject portions of the battery that are on fire, protecting the rest.
Eject them where? Instead of burning in place, would it shoot burning cells around like a roman candle?
You could just have the solder melt and the cells fall to the pavement to be raked apart.
Car’s junk, but at least they don’t have to wait for days.
Where is the fun in that though?
I want to calculate the cross section of a Tesla with respect to flying cells.
Would an ICE car act as a moderator? A dry field?
In any case, you don’t solder cells.
They don’t like the heat.
They are spot welded.
You’d have to have low temp solder holding the conductor strips together. And some sort of burn through/fall off weather cover.
Just far enough away from adjacent cells/modules to prevent the fire spreading. They don’t necessarily have to detach.
It’s a tightly packed box that is closed off from the underside, so the only direction you could eject the burning cells is up at the passenger space. That’s another no-no since all the plastics and fabrics burn so well it only takes 2-3 minutes for the entire car to light up.
What could be done is explosive bolts that drop the entire battery out and shear the cable harness, so the car can roll off the burning battery and expose it for the fire hose.
Like I suggested above. Low temp solder holding it together.
Steam gen and a tube to launch the burning cell into the neighbors car/house/cat.
45 degree angle should be optimum for range…unless car was moving…then tricky.
KISS. 45 it should be.