Originally Posted by
West Coast
There seems to be a couple of viewpoints on the effectiveness of water. Last recurrent there was a FAA video that compared a laptop fire suppressed with ice and another water. Ice seemed to be better at suppressing another flare up.
Not sure of its origin, but this video suggests ice is quite ineffective, and liquid water (lots of it) is the best:
https://www.youtube.com/watch?v=vS6KA_Si-m8. Ice test starts at about 7:40.
If I'm understanding correctly, the issue is that ice doesn't melt quickly enough to cool the battery cells and thus it winds up acting more as an insulator instead, letting them get even hotter. Similarly, Halon alone doesn't work well because it
only takes away the flames - it doesn't help cool off the battery at all. Since this is a "thermal runaway" the battery will continue heating itself up further (without oxygen or anything else external) until it is brought below a certain temperature threshold to stop the chain reaction.
According to the video water is best because it absorbs lots of heat and it's easy to douse the battery thoroughly. (And with modern Li-ion batteries, evidently there's not enough pure lithium to cause a problematic reaction with the water itself).