EV fires are devilishly hard to put out, there’s no two ways about it. Firefighters typically use huge amounts of water to put them out, cool them down, and stop them reigniting if possible. But there are other solutions too—like this giant blanket!
This week, we saw the City of Tallahassee Fire Department deploying one of these massive fire blankets to great effect. It’s a neat concept for tackling an EV fire, and it’s proving useful down in Florida.
The fire department was called to an EV fire by a charging station on Thursday afternoon. The vehicle in question was a Nissan Leaf, which can be seen smoking in images posted by the fire department.
Soon enough, though, it was bundled up and dealt with! It’s worth noting, though, that deploying the blanket is not necessarily an easy process. The action shots show that it takes some effort for a firefighter to drag the heavy blanket over the vehicle. It also requires the crew to approach the vehicle in close proximity. This means it’s best suited to a suppress a small fire or smoking incident, or to contain the risk of a vehicle fire restarting after it’s initially been put out. Indeed, in these images, it appears that the crew used water to fight the fire in addition to the blanket.
Multiple manufacturers produce fire blankets for tackling regular car and EV fires. It’s not clear which brand the City of Tallahassee fire department uses; The Autopian has contacted the department for comment. Bridgehill is one manufacturer of these fire blankets, and Spanish research institute Centro Zaragoza has a useful demonstration video on their use. The blanket can be seen to massively reduce the temperature of the burning car. When it is removed, the battery fire quickly reignites, revealing just how effective the blanket is.
Deploying the blanket must be done safely. Key to using the blanket is to ensure it’s making an effective seal with the ground under the vehicle. If air is allowed to pass under the blanket to the burning vehicle, the blanket will not be effective.
Various manufacturers advertise fire blankets as withstanding temperatures anywhere from 2200 F up to 4500 °F in the short term. Typical materials include silica and graphite for high-temperature resistance combined with silicone coatings.
Typical sizes are around 20 x 26 feet, with blankets usually weighing in around 60 pounds. The blankets can at times be reused, though fierce fires may damage the blankets to the point where they only last for a single deployment.
Traditionally, a fire blanket works by starving a fire of oxygen. This doesn’t work as well for an EV fire, where a lithium-ion battery is undergoing thermal runaway. This is because batteries in this state tend to produce a certain amount of oxygen as they degrade. This can sustain a fire even in oxygen-poor conditions.
These fire blankets work perfectly well on regular vehicle fires too.
The limitations of fire blankets are readily noted by the industry. Fire Isolator is a manufacturer of EV fire blankets, and explains this on its website:
Please note: While competitors may promise to extinguish electric car fires with a Fire Blanket, at Fire Isolator we know better. We’ve conducted many successful tests and the conclusion is always the same: the Fire Blanket is a great product to isolate fires and win time, but this product will not kill the fire of an electric vehicle on its own. Nor will those of competitors.
Fire Isolator notes that the blankets are best used in combination with other measures like water mists to help cool the batteries and reduce smoke output. Indeed, wetting an EV fire blanket can help make it nearly clean, reducing the outflow of toxic gases to the immediate area. The company also sells aerosol devices which can be thrown under the blanket to release potassium nitrate to try and inhibit the chain of chemical reactions that sustain a fire. Fire Isolator recommends monitoring the car’s temperature with thermal cameras once it’s under the blanket, and submerging the whole vehicle in water once it has cooled enough to do so.
If you’re in the business of fighting EV fires on the regular, you might want one of these in your tool kit. But then again, if you’re a professional firefighter, you probably already have one!
Image credits: Centro Zaragoza via YouTube Screenshot, City of Tallahassee Fire Department, T-ISS BV via YouTube screenshot, Hub Industrial via screenshot
Serious Question: Could this be paired with a Class D fire suppressant system to contain, cool, and disrupt the chemical reaction?
I think I remember enough from chemistry class to recall that water is “detrimental” to efforts to extinguish a lithium fire…
Great idea for mitigation of EV fires (yeah, for actually extinguishing such fires, not so much) which brings up the issue of dealing with SUV-sized EVs such as the Hummer EV and the Cybertruck.
“Typical sizes are around 20 x 26 feet, with blankets usually weighing in around 60 pounds.”
Such sizes wouldn’t be quite enough for the above-mentioned SUVs; plus, bigger sizes would be pretty damn heavy. 60 pounds ain’t trivial when dealing with something so unwieldy as a large (!!) blanket.
Not to mention that it seems like a Cybertruck with all its sharp edges could potentially shred such a blanket; even just one cut could render the blanket ineffective.
Still, such blankets do seem like a useful component of any fire department’s repertoire.
At that point, a bulldozer used to push the entire thing into the nearest lake would be the most effective strategy.
So, this can’t put the fire out because the fire is self-sustaining. You can theoretically use this to isolate the fire temporarily to move people and things away, but is it better to spend time deploying the blanket or just moving the things away in the first place?
Props to Fire Isolator for accurately representing their product. Honestly, this seems much more useful for ICE fires that do require oxygen to continue burning. The usefulness in EV fires seems much more dubious to me.
Not everything can be moved. What this could also do is buy time to get other resources on site to better deal with the situation without needing to try just flooding the vehicle with water to keep the fire suppressed.
It might be possible to help keep fire crews safe by lightly weighting the edges of the blanket and attaching metal rings to the corners just outside of the weights for ropes to pass through. That could allow firefighters to stand further back as they drag the blanket over the car and achieve a more successful seal.
I’m was thinking wetting the area.
I wonder if that would work on my wife’s hot flashes?
That would probably solve a lot of problems…just buy it for bed…it is a blanket after all! Ha ha
Fire blankets are a great idea. I don’t have an EV, but I keep a portion of an old welding canvas under my sink in case things get outta hand while I’m cooking.
Way better than a box of baking soda—and less cleanup
You can buy fire blankets specifically designed to be stored in a kitchen, just in case.
Hard to cover a burning parking garage with a blanket.
Ferb, I know what we’re going to do today!
Does concrete burn?
Booooo! I designed and developed these back in 2019. Only to get zero press coverage (I tried), and fire departments were interested until you told them the price. These also fall into the trap that mine did. They’re just too small. They won’t cover a anything other than a compact EV. Partial coverage does nothing.
At least testing it was fun though!
Hate it when that happens. I had an idea a long, long time ago for little packets of drink mix that you could add to bottled water. Everyone thought it was a stupid idea so I never did anything with it. Still kinda bitter about that one.
I just saw the EVs trending bigger and bigger, yet the cost increases with the square…stupid area.
Also, all it takes is for a change in battery chemistry to make these runaway reactions obsolete. The blankets work great with ICE vehicles too, but again…size size size.
I also didn’t have the budget to market appropriately and got out before I lost too much money.
Still, setting cars on fire with firefighters was pretty damn fun. I have a bunch of pics from those tests.
I’d love to see them and hear this story! Hit me at lewin@TheAutopian.com
We’ve become friends with the fire chief near our cottage (who also runs a logging and construction company – small town Ontario). They have the blankets but unless it happens to be at the tesla charge station in town their method/plan is to let it burn itself out and make sure that it doesn’t start a forest fire.
Good idea except if you’re downwind of the toxic cloud.
It always bothers me a little when IR cameras are used in this way.
The car is clearly hotter than the blanket, but showing an IR image of the blanket does not mean the car is now 107 degrees, it means the blanket is radiating that much. The battery is still hanging out down there doing it’s thing.
You can see at 20:21 when they are pulling the blanket off that the car side panel is still very hot, but an infra red camera is not picking that up when it’s covered with an insulated blanket.
IR camera is fine, used this way, it’s the implication that it’s suppressed the fire.
It shows that they’ve made it safer to be near the car itself. But that’s not how they presented it by claiming of “re-ignition” of the fire which is false. It was a fire under the blanket, you just couldn’t see it.
Much like a kid closing the bedroom door instead of actually cleaning their room.
I like and agree with your explanation.
The camera does tell you something, but it’s the explanation that goes along with it that is really critical.
Don’t lithium-Ion batteries provide their own oxidizer in thermal runaway? Meaning they can’t be snuffed out completely?
Correct.
This blanket doesn’t reduce the temperature, put out the fire, or stop/cause re-ignition. It provides a barrier between people and the battery fire beneath it to allow you to do other things to prep – like move other flammable things further away from the fire.
yeah, all I could think is that this helps buy time.
It also protects firefighters from tires that explode from the heat sending nasties every which way.
I’d wager it does reduce temps – while the batteries produce their own oxygen, having less available from the atmosphere would slow things down considerably
I saw this story in my newsfeed this morning. Mercedes EV exploded all by itself in a parking garage in Korea. They have video embedded in the article. What scared me is the article says it took 8 hours to extinguish the fire.
https://koreajoongangdaily.joins.com/news/2024-08-01/business/industry/Sixteen-injured-after-MercedesBenz-explodes-in-parking-lot/2103770
As explained above, yes
Thanks, I read again and see that now. I missed that the first time.
Solid-state sodium-based batteries can’t come soon enough.
Sodium Ion batteries are very unlikely to replace Lithium Ion batteries. More likely they will replace lead acid and other applications where cost matters more than energy storage density by size or by weight.
Patience, patience. The fossil-fuel free future won’t be built in a day.
Damn this is a good idea. Now we need to see this deployed far and wide.
They may be more widely used that us laypeople realize. Even the small department in my town has an EV blanket.