Originally Posted by DIYguy
I think the problem with Lipoly (not lifepo) is that the metal oxide provides the oxygen during thermal run away. Excluding air, or surrounding with halon, will do nothing to stop it.
Nothing reactive is going to work well on a runaway pack. That needs to be proactive. A system should be in place to shut it down before the temperature becomes unsafe, not after.
Normal suppression for metal fires is "D" class powders, but they would do very little except make it more dangerous by insulating the pack with a hard shell. Think firecracker.
#1 is to get the driver out alive. #2 is to minimize damage.
To get the driver out, a firesuit and Halon would be the best choice. If the fire was not a runaway battery, it would do job #2 without damaging the equipment.
Flooding the individual cells with water will stop a runaway pack. You can't carry enough water onboard to handle >200lbs of batteries though. You need a firetruck. And you'll do some unintended damage with water.
Aqueous foam is not a good choice, nor are CO2 systems. They don't pack nearly the punch of the same weight of Halon.
I will probably test Halon (used correctly) on a runaway when I get around to it, but we are talking about a $1000++ test. I think the FAA testing was invalid for EV's, since it involved just small, low voltage battery packs, not high amp, high voltage situations. They did not attempt to use the cooling effect of 1301, and only used short bursts of 1211, not sustained. However, the FAA still requires Halon on board last I heard.