It’s absolutely true that combustion-engined cars catch fire plenty, and have been doing so for well over a century. Gasoline is flammable, and fires do happen, no question. But even with that in mind, modern EVs are changing the car-on-fire game dramatically, something that’s been most recently seen in places like Florida that have been hit with hurricanes and the resulting salt-water flooding. Salt water wreaks havoc on EV batteries, and EVs have been catching fire at alarming rates. Even worse, the way these cars burn is so dramatically different than how gas cars burn that it’s requiring new methods to deal with the fires, not all of which are ideal. This Good Morning America clip shows these issues in a stark way that made us think it was worth showing you, in case you missed it.
Here’s the clip; also, I don’t recognize any of these people, which reminded me that I haven’t watched GMA since that guy who sounded kinda like Bullwinkle was a host. But that doesn’t matter, just watch:
So, what’s going on here, exactly? On a very, very basic level, the saltwater is interacting with the chemistry of a lithium-ion battery to cause shorting and thermal runaway conditions. We’re currently finding a proper EV battery engineer to do a deep dive on this, but until then it’s just grimly fascinating to see how these fairly unexpected (well, in the layperson’s eyes) issues that come with, for the first time in America, a genuinely significant number of EVs on the road.
[Editor’s Note: Generally, we don’t like to discuss technical topics without input from engineers, but this video is fascinating unto itself, so we figured we’d show it while we await input from battery engineers, who can dive a bit deeper into why this all happens. -DT]
I mean, this is pretty unprecedented when it comes to car fires: dumping a car in a water-logged ditch an attempt to keep it from igniting again?
Lithium-Ion batteries are incredibly energy dense, and are susceptible to a process known as thermal runaway, where the battery “enters an uncontrollable, self-heating state.” This is partially why EV fires require about ten times as much water to extinguish, and why the batteries, which may still be producing heat internally after initial fires have been put out, can reignite — even a significant amount of time after the initial incident.
That’s why the storage of burned-out EVs in Florida look like this:
The incredibly low density of this sort-of scrapyard is because any of those flooded cars could reignite without warning, and the distance can help prevent one burning car from igniting others. Here’s an aerial view of a similar lot, full of Teslas:
Here's the difference with gas cars vs. EVs post-hurricane. Here's aerial footage of impacted cars. Gas cars are squeezed together like sardines, AND YET the EVs are spread out. Why? Potential for fires as the battery breaks down from saltwater. FULL LINK: https://t.co/R9xVcqjYt0 pic.twitter.com/vh1C4dTiNb
— Jimmy Patronis (@JimmyPatronis) October 21, 2022
I know all cars can catch on fire, and I do not think EVs are inherently more dangerous than other cars in general. However, in this specific context — flooding — especially salt water flooding, there really isn’t any comparison with combustion cars. Combustion cars get ruined when flooded, but generally don’t catch on fire as a result of being water-logged.
This is all kind of new territory, and it’s clear that new procedures and precautions need to be developed. TThe NTSB does have guidelines for Emergency Responders for dealing with Li-ion fires, and Florida Chief Financial Officer and State Fire Marshal (shouldn’t they have two people to do these jobs?) Jimmy Patronis issued a letter to over 30 EV carmakers, though it’s addressed directly to Elon Musk, who I guess can just tell everyone else about it:
Mr. Elon Musk
Chief Executive Officer
Tesla
13101 Harold Green Road
Austin, Texas 78725
Dear CEO Elon Musk:
As you are aware, nearly three weeks ago Hurricane Ian impacted Florida’s Southwest coast, inundating the area with salty storm surge waters. The Category 4 hurricane was so massive, storm surge reached 16 feet in certain areas and went as far inland as downtown Fort Myers. From my experience in traveling the state, there were a tremendous amount of Electronic Vehicles (EVs) in this part of Florida, and we now know for a fact that any EV that was submerged in saltwater is a fire risk.
As the National Highway Transportation Safety Administration (NHTSA) confirmed last week, “Test results specific to saltwater submersion show that salt bridges can form within the battery pack and provide a path for short circuit and self-heating. This can lead to fire ignition.” The federal agency also confirmed that, “Lithium-ion vehicle battery fires have been observed both rapidly igniting and igniting several weeks after battery damage occurred.” Further, I saw with my own eyes as North Collier Fire Rescue fought an EV fire that continuously reignited. It was surreal, and frankly scary, watching fire teams fight this EV fire, using tens-of-thousands of gallons of water to cool the batteries, and then again watching the EV reignite. I even found out later that the car reignited on the tow truck. Florida firefighters have been the tip of the spear in hurricane recovery operations, and more has to be done to help these heroes deal with the unique challenges of EV fires. The fumes from the fires are dangerous, fires reignite, and fire teams don’t have a lot of tools at their disposal in dealing with these lithium-ion vehicle battery fires.
The unfortunate reality is that there is a population of vehicles that could spontaneously combust, putting our first responders at risk, and the manufacturers are nowhere to be found. For as big a risk as this is to fire teams, for companies who have received an immense sum of subsidies from taxpayers, I would have hoped the reaction by manufacturers would have been more robust – especially as these EVs supposedly have a tremendous amount of technology and connectivity. There could be a family who evacuated, whose home was left relatively intact from Ian, who may still lose everything because of an abandoned EV, left in their garage, that catches fire as a result of salty storm surge waters. That’s a risk that requires more of a response from manufacturers than just telling customers to consult the owner’s manual.
Many of these families are trying to rebuild their lives following Ian, and manufacturers should really be doing more for families in their time of need. That’s just good corporate stewardship.
In this context, we need EV manufacturers to step-up, demonstrate leadership and partner with the State of Florida and local officials in this recovery to ensure that:
1. Outreach to EV owners by manufacturers takes place, alerting customers to the risks of EVs and fires from salty storm surge waters.
2. Identifying and safely relocating compromised EVs to appropriate spaces for monitoring.
3. Having an on-the-ground presence and offering assistance to customers and first responders in mitigating these risks.
Because each and every EV model is different, and because much of this information is not publicly available under the premise of trade secrets, we need more information that is specific to each and every EV model. As such, I am requesting the following information of your company:
1. Has your company conducted any analysis on the effects of saltwater intrusion on the lithium ion batteries in your vehicles and their risks associated with fires?
2. Over what period of time does a fire risk exist from a vehicle impacted by saltwater, or does the risk exist indefinitely? While NHTSA confirmed to our office that “fire ignition” can occur “several weeks” after exposure to saltwater, firefighters and other first responders need greater specificity to accurately assess, plan, and act on these risks.
3. Can you provide to the state information on the location of these EVs in the runup to impacts from Ian?
4. Can you provide a point of contact for your company that can be shared with emergency officials?
5. Are there any fire risks associated with chargers that were submerged in storm surge?
6. Do you have the ability to assess whether an EV, impacted by storm surge, is operational and currently being used?
7. To your knowledge, is there any fire suppression technology that has great success in ensuring fires do not reignite?
8. As much of the Central portion of Florida was flooded by heavy rains, is there any associated risks with submersion in freshwater?
9. Will you forego any attempts to limit information, under the premise of proprietary secrets, and agree to make the provided information to above questions publicly available as to facilitate greater coordination amongst industry experts as we work in real time to mitigate risks?
Please provide answers to my office for public distribution no later than October 24th. Again, the recovery in Southwest Florida is still ongoing. There are still families who have not gotten to their homes and families who are sifting through their belongings, making hard decisions. While this information is critical to mitigating further suffering, we really need to see more action by your company on a product that no one knows more about better than your engineers and your experts.
I look forward to your response.
Sincerely,
Jimmy Patronis
Chief Financial Officer
So far there has yet to be a formal response from any carmaker to the letter, which has valid questions.
While we’ve certainly seen EV fires before, Hurricane Ian forced Florida into becoming an unwitting testbed of what happens when large numbers of EVs are salt-water flooded en masse. The results aren’t great.
I have a few questions. First How about EVs driving on salt covered roads going through the car wash?Second if all these cars are totalled why worry about keeping them apart? Third cant they just remove and store the batteries in a shipping container and fill with some fire fighting foam?
I remember it being recommended that you put a LiPo RC battery that’s no longer any good in a bucket with salt water to make sure it’s fully discharged before getting rid of it. Same thing here I guess, but on a much bigger scale and not where it’s wanted. lol
Sounds like salt water boat ramp fails might soon get a new category. You’re worried about loss of range towing your boat with an electric truck? Eh, it’ll catch fire after launching, anyway!
I guess they’ll eventually have to consider all damaging possibilities in order to upgrade their safety. I’m sure they’ll get to it, but these are lab drawn EV designs which still lack years of real world testing.
I enjoy offroading quite a bit through mud and water (Use a 4×4 gen 1 Xterra in tropical zones), but whenever I think about getting an exciting off-road EV, I immediately hit the anxiety wall of “things that could go wrong”. No amount of under armor is going to protect those floor batteries in the worst rock grinding conditions. Do the current designs even protect from sideway toppling crunch?
So in theory could they rely on some internal (ie inside the car body) fire suppression mechanism? Like a thermal blanket to smother it and inject some kind of foam to destabilize the chemical reaction? I know that we have had years to figure out how to put out chemical fires but I am not sure how reliable that would be a scenario like this. Or put the battery in a separate partition that contains temperature released smothering agent? IDK, using my brain and my knowledge of thermal fires from 3d printers to come up with a scheme. It seems like it should be possible but it would add another complexity layer and cost but we are seeing how this seems to be something that is a MUST have.
Gridlock induced by dead EVs on hurricane evacuation routes would not be a good thing.
I wonder if pouch style battery packs (Chevy Volt/Bolt) fare better than the cylindrical cell packs (Tesla)?
Hopefully this gets the FMVSS updated to address battery packs. Don’t forget, these are small packs we’re seeing compared with what is coming on electric heavy vehicles.
Knew I forgot something. Yea lithium does an accelerated decomposition reaction with saltwater. Lithium Ion batteries are crazy in that everything in it feeds into runaway when things go wrong. They’re mostly safer in safe conditions, and horribly dangerous in incorrect conditions. This is probably one of the few times “spontaneous combustion” can actually be used seriously in a sentence.
As you said, best thing Torchinsky could do is get an inorganic chemist to spell it out. Dad’s a retired corrosion chemist PhD (hence the interest); I might just ask him about it over a beer.
Dad’s a retired corrosion chemist PhD (hence the interest)
He may have already read it, but if not, this may be up his alley:
Rust: The Longest War, by Jonathan Waldman
https://bookshop.org/p/books/rust-the-longest-war-jonathan-waldman/7061592
I recommended it to David back at Jello Picnic some years ago, and I think a lot of Autopian readers would dig it, too.
[Note: this is a repost of an earlier comment, which seemed to lose its formatting]
I’ll just put this out there, purely for fun (though there are many truths in it as well):
https://www.youtube.com/watch?v=80qsbhU66HQ
I’m a scientist, and believe the mountains of data showing the correlation between human activities and increasing temperatures (my undergraduate thesis, many, many decades ago, was on photovoltaic energy). If we want to save the planet, and ourselves as a species, we need to stop burning things to generate power. After all, this is the only planet we have, so it seems like a good idea to not make it uninhabitable.
But… the ‘field of dreams’ approach, of ‘let’s legislate it and hope it somehow magically happens’ is not the way to do it. You can’t just will something to happen because you want it to be a certain way. While as a planet we will need to move to renewable sources of energy (solar, wind, tidal, etc.) if we are to survive, science also dictates some unpleasant realities that legislation is not going to overcome.
Transportation will ultimately, someday, be powered by something other than fossil fuels. But it’s a mushroom-induced fantasy to think everything will be ready by 2030. Making sure EV batteries are flood-proof is just one of many details that have to be worked out.
First and foremost, we are a country that still generates almost 2/3 of its electricity from fossil fuels.
https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php
Unfortunately, many people do think that electricity does somehow ‘magically comes from the wall outlet’, and assume it’s ‘green. Like my neighbor, who self-righteously plasters ‘Zero Emissions!’ bumper stickers all over her Leaf and smugly lectures me whenever she sees me. When I pointed out to her that our state currently generates 95% of its electricity from natural gas, and that an energy balance analysis would suggest her Leaf and my ICE car produce about the same net carbon emissions –
https://www.scientificamerican.com/article/electric-cars-are-not-necessarily-clean/
her brain exploded and she refused to accept it. If every car on the road instantly became an EV, it wouldn’t solve the problem that fossil fuels are still used to generate the majority of the electricity, for the country and the planet as a whole.
The pesky little problem no one wants to talk about is that the more important bigger first step must be to transform our electric generating grid to be based on renewables. But that’s not addressed because of the $5-$10 trillion cost to do it. Are people going to be willing to pay for that?
A good friend is a retired senior Ford exec. He tells me their internal analyses show a massive problem with transmission grid capacity in this country. Again, if every car magically became an EV, the power grid couldn’t handle the increased demand. California is already asking EV owners to restrict charging times.
The biggest elephant in the room is the need for this to be a global endeavor. It won’t be enough even if the U.S. was totally green, if China, India, and the rest of the world are still burning fossil fuels for their power.
Any form of power has a price. There is no free lunch. Another little considered issue is lithium. For many reasons it’s not wise to exclusively rely on China for it. So instead, this country will take away and pollute Native American Paiute and Shoshone land to do it:
https://amp.theguardian.com/us-news/2022/oct/18/lithium-mining-nevada-boom-car-battery-us-climate-crisis
From a tribal member: “Will turn what is left of my ancestral homelands into a sacrifice zone for electric car batteries.”
There are likely solutions for most of these issues. Given enough time, money, and research. Science and engineering will dictate the pace of development and readiness, not disingenuous, self-serving politicians or well-meaning but misinformed sanctimonious zealots.
As Neil deGrasse Tyson said, ‘The thing about science is, it’s true whether you choose to believe it or not.’ Ignoring reality doesn’t change reality.
Just park the damaged cars in a dumpster with seals. If the fire starts, fill the dumpster with water.
That’s exactly how fire departments now often deal with EV fires if they have the equipment, dump the car in some container with a crane and fill it with water.
What’s done with the water afterward? I can’t imagine that no hazardous chemicals leach into it as the battery fire burns out.
Just park the damaged cars in a dumpster with seals
I’ve got a walrus guy, would those work in a pinch?
I love how they put the EVs in the grass lot that can catch on fire, instead of the gravel lot.
To be fair the Grass was recently watered.
OK, I thought about this a little more and I realized that we do actually know how to solve this. Humans have been building electrical devices that can operate indefinitely in a marine environment for decades at least. Remote underwater vehicles spring immediately to mind, but also all the electrical infrastructure, including entire power plants, that exists in, on, and under the sea. Engineers have solved this problem before, many times over. I would be surprised if the various terrestrial military robots out there—many of which are powered by Li-Ion batteries—don’t have this kind of thing in their spec.
So we do know how to keep saltwater out of battery packs, it’s just that when it comes to EVs, we haven’t bothered. Looks like it’s time to change that. This is a solvable problem, it’ll just cost money. That means it would probably have to be a regulatory requirement, because we all know how automakers feel about spending money on safety systems when they’re not being legally compelled to do so. Seems to me though that it’s going to be pretty important, as EVs become more and more common.
That’s been my thought all along, ever since I heard people insisting that I can’t take my Bolt through a car wash and that driving in the rain is risking electrocution.
I know the battery is weather-proofed, but I had never thought that it wouldn’t be flood-proofed. I suppose that someone might not have considered it since “submarine” isn’t a normal operating condition for the average car. Maybe this will be the eye-opener to better seal the batteries in future models. It can’t be *that* tough to do, can it?
It’s not like they’re already unaffordable let’s add another layer of complexity and cost now. Not just unaffordable, but made of unobtainiam.
Thank you for writing about this so clearly, and without the sensationalism that I’ve seen elsewhere. What we’re seeing here is a real problem, for sure, and I’m glad you’ve managed to open a space where it can actually be discussed instead of just screamed about.
I don’t actually have a lot to add, I think the article covered things reasonably well. This is a new failure mode that seems unique to EVs, and it’s pretty bad. Bad enough that it seems like it will have to be somehow addressed—flooding happens, and as EV adoption grows, so will the potential for this kind of secondary disaster. Imagine if 100% of the cars in Florida were EVs, instead of the low-single-digit percentage us today? Imagine if home battery backups (which are essentially stationary EV batteries) were as commonplace as portable generators? It would be catastrophic.
This should be a wake-up call to the automotive industry and its regulators. I’m not sure what the solution should be, but we should get working on one before this becomes an even bigger problem.
Did you know that automobiles are not covered by the National Electrical Code? OEMs are more or less free to do whatever they like in that regard. The NEC’s main purpose is to prevent electrical fires (seriously—it’s published by the National Fire Prevention Association). Maybe it’s time to bring automobiles into the fold, and set some safety standards for their construction? As an apprentice electrician I will happily agree that the code can be a pain in the ass sometimes, but you’ve got to admit that electrical fires are pretty rare around here, and we have the NEC to thank for that. Perhaps that offers an answer.
I’m sure people are thinking about how to deal with this. I’m equally sure that other people are thinking about how they can get out of having to. EVs—and renewable energy tech in general—offer massive benefits to society, but like any big new technology there are going to be new dangers and drawbacks. We need to meet them head-on. There’s no excuse for repeating the mistakes of the past, and sweeping the problems under the rug until they’re too large to ignore. A solution clearly needs to be found.
Ditto on this first paragraph. 100
Not a engineer, but a Physicist with layman words. Bit of chemistry here, but hear me out.
1. Li-Ion batteries have a anode and cathode, which function as a negative and positive pole. These are divided by an insulator called a “separator”, and lithium ions can freely pass back and forth between these poles, generating electrical current. When this separator is compromised, total discharge happens a lot quicker, and there’s an exponential increase the battery conductance, akin to a “short circuit. The result is increase in current (amperage), which feeds back into it, damaging the separator even more, and constantly increasing temperatures. This is an exothermic reaction and is also know as thermal runaway.
2. As for saltwater, when it seeps in to charged spaces, it separates into Na(positive) + Cl(negative). These ions migrate to each corresponding “pole” (negative ion to positive pole, positive ion to negative pole). This generates an electrical current, which increases temps, which directly affects battery integrity and possibly the separator. The electrical current also causes electrolysis of the saltwater, which becomes chlorine and hydrogen gas. Hydrogen, as we know, is highly flammable. The hydrogen turns out to be important.
3. The infinite added ions and saltwater electrolysis that happens in saltwater flooding, result in an inevitable thermal runaway that not only feed back into it, but promote this process. Eventually the heat fully compromises the separator/insulator of every battery, amperage and temps go through the roof, followed by combustion (powered by hydrogen), and all hell breaks loose.
I’m sure someone can give a better explanation, but I’ll take my nerd glasses for a spin today. Saltwater is known as highly corrosive, but what that really means is that its way more conductive than fresh water. As for lithium batteries, this is more akin to a design flaw, which isn’t really limited to cars. Until better separator materials come by at least, its just how batteries are going to work.
Chemist here. I will start by saying that as an Engineer, David will of course look to other engineers. His best bet would be a battery chemist. We all like to toot the horns of our own club.
Your explanation was pretty good. I will add my 2 cents but take them with a grain of salt because I am not an expert in battery chemistry (my focus was organic chem).
Most of the damage comes from the salt water being a good conductor. When you immerse a battery in salt water, a circuit is created. As the battery discharges, it heats up. The uncontrolled circuit continues to heat until the battery is compromised. Electrolysis of NaCl is probably not an issue. The major issue I see is that as soon as a hot battery in salt water is compromised, the Lithiated carbon anode is exposed to water. The Lithium metal immediately reacts with water to produce Hydrogen gas, LiOH and more heat. The heat generated further accelerates decomposition of the surrounding batteries and the runaway begins.
Where I work, we deal with some exothermic reactions on multi-ton scales. We have to know how much energy can be produced and how to shut it down if a runaway begins.
Knew I forgot something. Yea lithium does an accelerated decomposition reaction with saltwater. Lithium Ion batteries are crazy in that everything in it feeds into runaway when things go wrong. They’re mostly safer in safe conditions, and horribly dangerous in incorrect conditions. This is probably one of the few times “spontaneous combustion” can actually be used seriously in a sentence.
As you said, best thing Torchinsky could do is get an inorganic chemist to spell it out. Dad’s a retired corrosion chemist PhD (hence the interest); I might just ask him about it over a beer.
Isn’t it enough that the saltwater inevitably causes electrical shorts everywhere it goes? Short out enough cells and one of them is going to go into thermal runaway. After that, it’s all over—fire is inevitable.
well does this not also work for say a jeep Rubicon 4Xe? I mean if that battery leaks regular old river water from water fording won’t it also short and potentially over heat?
I haven’t seen/heard much combustion events with li-ion batteries in freshwater fording. But then again, we’re getting EVs combusting in the freeways with no water required. Statistically, the more EVs they sell, the more thermal runaway events we’ll see, and the safer the development standards will be. This is probably a case of “early adopter tax”.
Saltwater is specifically the issue in this case (such as coastal hurricane flooding). Its highly conductive/corrosive vs freshwater.
The freshwater that you get in a stream crossing is gonna have a lot of dissolved minerals in it though, it’s not like it’s DI. I think manufacturers need to get a lot more serious about sealing up these battery packs. The new Hummer just got recalled for water ingress into the battery, and that came from just a poorly-cured bead of PU sealant. If I put something on a roof that was sealed with nothing but a single layer of caulking my customers would freak out, and while a roof leak is very bad it’s not burn-your-entire-family-to-death bad.
– God this page needs an edit button. I’m even starting to miss Kinja.
I guess they’ll eventually have to consider all damaging possibilities in order to upgrade their safety. I’m sure they’ll get to it, but these are lab drawn EV designs which still lack years of real world testing.
I enjoy offroading quite a bit through mud and water (Use a 4×4 gen 1 Xterra in tropical zones), but whenever I think about getting an exciting off-road EV, I immediately hit the anxiety wall of “things that could go wrong”. No amount of under armor is going to protect those floor batteries in the worst rock grinding conditions. Do the current designs even protect from sideway toppling crunch?
By the way, what branch of physics do you do? My wife did her PhD in NMR methodology for biophysics applications.
Like your wife, I ended up deviating from pure theoretical physics into biomedical physics right after undergrad, then just medical physics (cardiology stuff w/ genetics). Worked as a researcher for a while, but just went all in with the medical part. Currently about a year out from an MD degree.
Did quite a bit of research in electronics and fluid dynamics before switching over. So I tend to keep myself up to date on publications. Theres alot of overlap in those subject to bring over to the medical field. Guess I still consider myself a “Physicist” because medicine is just spicy physics within a body.
Fun tidbit: I’m actually a geneticist as of now, but that wouldn’t sound too convincing in a car blog lol.
Theres a physicist in all of us.