this post was submitted on 05 Sep 2023
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Depends how well the battery is packaged. Here's a cheap disposable AA lithium battery dropped in a bowl of water - it bursts into flames almost instantly:
https://youtu.be/cTJh_bzI0QQ?si=dgkKYSqo-zXulNt_&t=345
However they had to disassemble that battery. If you just dropped the undamaged battery in the water nothing would've happened.
So - this really is Tesla's fault. They should be wrapping a water tight barrier around the batteries. It's one thing for a battery to catch fire after a serious crash. Fair enough. But it shouldn't happen in floodwater.
Try the same experiment using salt.
The problem isn't really about the water getting things wet, more about the salt in it adding conductivity that can corrode metals making holes and also shorting any exposed electronics.
As much as I dislike tesla and it's unnerving ubiquity along with being under an unstable leader, we have to remember... These are land vehicles, not submarines. They weren't designed for prolonged immersion in salt water. Most of the environmental testing very likely revolved around using chambers to simulate different weather patterns.
Pressure and immersion testing are generally used only for individual components that do get sealed, permanently. So if you were to seal the battery pack or even just sections, you would still need to connect it all to the electronics like the BMS and in/output. With enough time just these two points could allow a path to short the battery causing the cells to overheat, expand, crack any seals (further increasing the reaction), build enough pressure and eventually pop like a shotgun shells fired outside of a barrel
I'm guessing you don't live in a city that has hurricanes or tropical weather in general?
Cars are submerged in water all the time in certain parts of the world and if you live in one of those places then there's nothing you can do to avoid it. Every car I've ever owned has at some point been exposed to water depths deep enough that the tesla battery would've been fully submerged.
It's not uncommon for a tropical storm to rain billions of gallons of water over a small area in a short period of time. When that happens you just can't keep your car dry.
If it destroys the car, OK that's an insurance job. But if the car catches fire it has the potential to burn down buildings/etc which is really really bad especially if it happens during sever weather when a fire fighter will not be able to respond potentially until days later even if the nearest fire station is a few city blocks away.
I'm sure this is a solvable problem. Also - it's worth noting only two cars caught fire and I'd bet a lot more than two EVs were submerged a widespread flooding incident like this one. There must be more to it than just "if you expose an EV to salt water, it'll burn".
One of the YouTubers I watch, Tavarish, is rebuilding a flooded McClaren. McClaren went to great lengths to water proof the car (IIRC almost all the connectors for the electrical harness and many of the other cables/wires in the car were all fine). The car is an engineering marvel and it still had damage done to the battery and almost every inch of the car had water intrusion.
Not disagreeing with you but salt water tends to fuck shit up. Maybe a better solution is some kind of system with a series of sensors and other inputs that could disable the battery until it's checked out? Or maybe better education on how dangerous lithium batteries can be.
There's not much to disable unfortunately. Provde a short circuit path between the anonde and cathode and you're going to get thermal runaway. You could try inside the cell protection, but that's going to be pretty expensive given a Tesla containing thousands of smaller capacity cells. Other OEMs use larger "large format" pouches, but they still a have hundreds.
He does find some other worrisome things when going through that car.
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