The larger problem is the toxic gases being released.[1] For my latest safety training in the maritime industry the handling of lithium battery fires was essentially put yourself upwind and let it burn it self out to prevent any exposure.

[1]: https://www.nature.com/articles/s41598-017-09784-z

A lithium-ion battery fire is distinct from a lithium metal fire. (The paper linked here is on li-ion battery fires)

Li-ion battery fires are commonly fought with water.

Sorry I was not being clear, I realize that a metallic fire is different from a battery fire. Updated the comment to reflect that.

The case we primarily discussed was an EV fire on the car deck of a ro-ro ferry.

And the conclusion from the paper is important:

"Using water mist resulted in a temporarily increased production rate of HF but the application of water mist had no significant effect on the total amount of released HF."

Essentially, our conclusion was don't touch it, if you have to then cool flammable things in the vicinity and as a last resort if things are about to spiral out of control put water on it.

As the article says, the fire department used a new approach which was to submerge the car in a pool of water and leave it over night. I'm surprised this didn't cause more issues (I guess the battery wasn't actually damaged or on fire before hand), but it's good to know it works. Still, it needs a lot more equipment than a regular car fire.

Actually, the Belgian fire dept has done that multiple times already. At least once in the Antwerp harbor with a Volkswagen. They where being followed by a tv crew at the time, so it’s well known to the public and we got some explanation as to the reasoning of why they’re doing it like this. (“Helden van hier” S04E08)

Episode on Youtube: https://www.youtube.com/watch?v=xWo8Sb0IE4U

In an electric car the battery is essentially the only part that can catch fire. If there's flames, the battery is already burning and you can't really put it out.

The only other thing would be an electric component overheating or shorting, but that would cause a small explosion rather than a continuous fire.