Fire departments are going to need to learn how to put out battery fires and have the relevant equipment available. If they are in the profession of putting out fires, at some point it's on them to know how to not waste 32,000 gallons of water as these vehicles become more common.
"Use lots of water" is actually the best practice for extinguishing these kinds of fires.
First of all, there are actually parts of the car that are on fire (plastics, fabrics, etc.) and may spread fire to the surrounding environment. You need to extinguish those.
Secondly, the battery system is not "on fire" in the classical sense. It's undergoing a self-sustaining thermal runaway. You pour as much water as you can on it to remove heat and break the chain reaction.
> You pour as much water as you can on it to remove heat and break the chain reaction
...For long enough to remove the immediate danger of the fire to the surrounding people. Such a damaged fully charged battery will probably undergo thermal runaway and reignite repeatedly as soon as it stops being cooled. The best bet is to just keep the fire under control and not let it expand while it burns itself out.
From their own Manuel:
FIREFIGHTING
USE WATER TO FIGHT A HIGH VOLTAGE BATTERY FIRE. If the battery catches fire, is exposed to high heat, or is generating heat or
gases, use large amounts of water to cool the battery. It can take approximately 3,000 gallons (11,356 liters) of water, applied directly
to the battery, to fully extinguish and cool down a battery fire; always establish or request an additional water supply. If water is not
immediately available, use dry chemicals, CO2, foam, or another typical fire-extinguishing agent to fight the fire until water is available.
Apply water directly to the battery. If safety permits, lift or tilt the vehicle for more direct access to the battery. Apply water inside the
battery ONLY if a natural opening (such as a vent or opening from a collision) already exists. Do not open the battery for the purpose
of cooling it.
Extinguish small fires that do not involve the high voltage battery using typical vehicle firefighting procedures.
During overhaul, do not make contact with any high voltage components. Always use insulated tools for overhaul.
Heat and flames can compromise airbag inflators, stored gas inflation cylinders, gas struts, and other components which can result in
an unexpected explosion. Perform an adequate knock down before entering a hot zone.
Battery fires can take up to 24 hours to extinguish. Consider allowing the battery to burn while protecting exposures.
After all fire and smoke has visibly subsided, a thermal imaging camera can be used to actively measure the temperature of the high
voltage battery and monitor the trend of heating or cooling. There must not be fire, smoke, or heating present in the high voltage
battery for at least one hour before the vehicle can be released to second responders (such as law enforcement, vehicle transporters,
etc.). The battery must be completely cooled before releasing the vehicle to second responders or otherwise leaving the incident.
Always advise second responders that there is a risk of battery re-ignition.
Second responders may choose to drain excess water out of the vehicle by tilting or repositioning it. This operation can assist in
mitigating possible re-ignition.
Due to potential re-ignition, a Model S that has been involved in a submersion, fire, or a collision that has compromised the high
voltage battery should be stored in an open area at least 50 ft (15 m) from any exposure.
Warning: When fire is involved, consider the entire vehicle energized. Always wear full PPE, including a SCBA.
Water, in general, isn't specific enough. Hot water definitely won't help. It's low temperature, high thermal capacity / high latent heat of vaporization extinguishants that are best. The FAA has a whole protocol and training materials on how to put out Li-ion fires.
The latent heat of vaporization of water is so high that the temperature of liquid water can’t possibly make a big difference (specific heat is 4.18kJ/kg/K, latent heat of vaporization 2,260kJ/kg.)
German cities are in the middle of equipping all fire departments with containers that they can flood with water to submerge EVs in. The idea is to let the EV burn, cool it with water, and then tow it under supervision of a fire truck to a fire station to put the EV into water for 1-2 days. Compared to ICE vehicles it's very complicated and binding a fire truck over a span of multiple hours instead of 1 or 2.
Tesla has a relatively comprehensive set of first responder guides on their website. They are all PDFs, which might not help people in the field, but they seem like a good thing to print out and throw in to a binder in every truck. Honestly, if I was tesla I would print, bind, and ship these to every fire dept in the country.
I mean the manual pretty much instructs to do exactly as it was done here:
> USE WATER TO FIGHT A HIGH VOLTAGE BATTERY FIRE. If the battery catches fire, is exposed to high heat, or is generating heat or gases, use large amounts of water to cool the battery. It can take approximately 3,000 gallons (11,356 liters) of water, applied directly to the battery, to fully extinguish and cool down a battery fire; always establish or request an additional water supply. If water is not immediately available, use dry chemicals, CO2, foam, or another typical fire-extinguishing agent to fight the fire until water is available.
> Battery fires can take up to 24 hours to extinguish. Consider allowing the battery to burn while protecting exposures.
I have no idea. I'm also not a firefighter. As electric cars become more common, we'll need to have a solution that is not "spend 4 hours trying and then call the manufacturer."
It's not water that puts it out, but low temperature to stop thermal runaway like the FAA advocates for Li-ion battery fires. <0 C salt water would be best.
The unsatisfying response in this case might just be: some fires can't be put out. At least, not quickly enough to matter for anyone inside the car. The priority in cases like this might just be to remove occupants from inside the car if possible.
According to Tesla's information, battery fires can be extinguished by using a lot of water. So, it is possible to do with an ordinary fire truck (and self-contained breathing apparatuses so firefighters can get near a burning car without breathing the fumes), but it might actually be a rare case where putting the fire out is consequential to the outcome for the occupants: I'd imagine in most cases they either got out in time or it was already too late by the time putting the fire out is a plausible option. Maybe I'm wrong about that, though.
Isn't removing occupants of any burning enclosure (be it a car, building, boat, ...) always the first priority? I can't imagine any case where a fire department would pour water on a burning car without first getting people out of it.
I would assume that they'd try to get people out first.
My comment is more addressed to people such as myself whose natural inclination is to regard a burning car as a bad situation that the fire department aught to be able to quickly remedy, and to suggest that most of the time putting out the fire may be a low priority.
I could imagine the fire department dousing a car if it was already too hot to get people out of safely, but I'm not a fire fighter and I don't know what they'd normally do in that situation.
Well how do you put out a battery fire? What new materials does every single fire station in America need to acquire? What new skills/training do local firefighters need? Who's going to pay for all this?
Ice, dry ice, liquid nitrogen would be even better. It's not about water putting out the fire directly, it's getting the Li-ion battery below thermal runaway to stop the self-immolation.
Maybe they can learn some techniques, but also car manufacturers must make the cars more ready for those kind of situations. It won't be the first time more "dangerous" vehicules are created, and technical solutions to be found (think of the liquefied petroleum gas design which had to have a safety valve).
I would design the batteries element with little robotic legs, so that when a thermal runaway occurs, they would disassemble and run away dispersing from the hot elements, to cool down each individually. </me mode="overengineering">
lol or to your local tire storage facility.. oil refinery... nuclear power plant... lumber yard with thousands of cut trees waiting for processing... paper mill... there’s lots of good options to pick from
What do you propose? Damaged batteries short and burn, it's the way it works. The energy needs to go somewhere. Damaged fuel tanks leak fuel much (MUCH) faster and burn much hotter and more dangerously. Do you demand that that be fixed before we allow ICE engines to become more common?
This whole "we couldn't put out the fire" nonsense is click bait. Battery fires burn longer, and that's important to know and requires different techniques to manage. But objectively they are safer than gas fires. Period. There is no serious debate on that point.
I think Tesla's car design is, for the most part, reasonably safe (their driver assist technology is debatable, but that's a side issue). However, there are design trade-offs they made to favor range and power over safety and weight. For instance, the cells they use are substantially more dangerous than lithium iron phosphate (LFP) cells. The latter have lower energy density, so they aren't the best to use in a range-optimized car. (I believe Tesla is now buying LFP cells from CATL for some of their model 3s. Not sure if those are just for the China market or if it's available elsewhere.)
I don't know if they could have done more with their batteries to prevent damage from causing thermal runaway. Maybe they could isolate modules from each other better, or use the built-in liquid cooling system in clever ways. (Maybe use the coolant to boil a reservoir of water, so all the excess heat gets used to make steam?) Maybe add heat shielding between the battery and the rest of the car. Maybe design the battery to detach from the car if it gets too hot.
At any rate, I don't think cars can be made to be perfectly safe, and a modern Tesla is reasonable, especially compared to a gas-powered car. However, the possibility always remains of improving upon Tesla's current design along every desirable vehicle attribute, including safety.
You think Tesla needs to rethink the fact that... batteries store a lot of energy? I really think you're missing the point.
Going full-on didactic on you: Vehicles have huge energy requirements to move them around. To meet those requirement they need to store energy on-board in some manner. This creates known failure modes where damage to the vehicle releases that energy in an uncontrolled way. That's bad. But it's completely unavoidable given the constraints of the system.
You seem to want Tesla to do the impossible and invent batteries that don't burn. Which seems ridiculous, given e.g. Ford's nearly-century-long failure to invent gasoline that doesn't burn.
The question you should be asking is "Are battery fires safer than gasoline fires?". And... duh. Yes, they are. And it's not even close.
No no no, logic works the other way around: you are the one claiming that this is a new and more dangerous technology.
If you want to do that, you are the one who needs to bring evidence.
I'm simply arguing from first principles: car batteries store less energy than fuel tanks and release that energy slower and over a longer period of time in a fire. Ergo, they are safer for pretty obvious reasons.
Most car fires do not actually involve the entire gasoline tank catching alight; as the gas tank is well-protected and not particularly near sources of ignition. An engine bay fire is much more common.
If gasoline is spilled, foam works well to extinguish it and keep it from igniting.
Once a gasoline fire is out and cool, it is going to stay that way,
Lithium-ion battery fires are self-sustaining thermal runaways. You cannot put out such a battery fire by smothering it; it does not need oxygen from the air. All you can do is try to keep it cool by running water on it.
Even after such a fire seems cool, it can reignite unexpectedly.
The actual gross volume of energy is not necessarily what makes fighting a fire dangerous or not; it's the unpredictability. Firefighters may be more worried about compressed gas-strut explosions (from hatches, hoods etc) than they are about the gas tank exploding.
> You think Tesla needs to rethink the fact that... batteries store a lot of energy?
Just as the environmental externalities of fossil fuels need to be internalized, so do the public safety externalities of the kinds of batteries in use, here. If its going to be a “price of doing business”, the right parties ought to pay the price.
Then, whether or not it is sensible to mitigate in manufacturing will be handled by the properly-aligned incentives.
But what are the externalities?! You and the upthread poster aren't elucidating any. All we have at hand is the linked article, which is... a fire. Batteries burn, in a safer and more controlled way than gasoline.
How is that a bad thing? What are you asking for battery or car manufacturers to do that they aren't already doing simply by replacing existing more-dangerous technology?
Reducing the battery capacity would make things better. We don't need such massive battery capacity for daily use but we buy them to support rare use cases.
