Malkoff        
Page 2 of 2 FirstFirst 12
Results 31 to 33 of 33

Thread: 11 tons of water to put out tesla fire!

  1. #31

    Default Re: 11 tons of water to put out tesla fire!

    All of the arguments I've heard about why electric cars are bad, and the treatment towards electric car drivers, I got when I drove a propane powered vehicle, even though they had been on the road for a very long time. Its why many places have poorly thought out vehicle modification laws, as a knee jerk reaction to anything that might be dangerous, rather than actually assess real risk.

    Sure as EVs become more common, vehicle fire fighting will adapt, just as vehicle extraction has changed with cars being better engineered for roll over protection, crumple zones etc. I've yet to hear someone complain that "you shouldn't buy SUV x because the pillars are so strong it will take the fire dept longer to cut you out of the car"

    Like the move from steel to plastic fuel tanks, manufacturers will come up with methods of heat dumping, battery isolation. It might not work out practically in the math, but how many BTUs of heat could be dissipated by 20kg of CO2 in a venting heat exchanger? A system by which a constant flow of CO2 is vented around the battery pack? Just spitballing ideas, its probably not practical, but the point is that under certain circumstances there is always a way to design in an added fail-safe to manage an unexpected risk.

  2. #32

    Default Re: 11 tons of water to put out tesla fire!

    Quote Originally Posted by usdiver View Post
    Since lithium is a class B Fire is there a reason they used water?
    For one thing, they had water. To a man with a hammer, every problem looks like a nail.

    But seriously, you cannot "extinguish" a lithium or Li-ion cell fire with water. You can't smother it, take away oxygen. This isn't fuel, it is stored energy that is going to be released, perhaps 100KWH. Wouldn't matter if the battery was on the surface of the moon.

    The second reason a firefighter uses water is to cool off fuel, and that is actually a good idea here. The problem likely was you drew a winning number in the Li-ion cell lottery and one of your cells caught fire. The fire will quickly spread to nearby cells, heating and popping them, and on. If you can put enough water on the unexploded cells, the heat of the fire will not pop them, the chain reaction will slow.

    A Lithium fire would be Class D fire, but unlike primary cells (CR123A, etc.) there is no lithium metal in Li-ion (ask any meth cook). The primary fire is the electrolyte, which would be Class B, flammable liquid.

  3. #33

    Default Re: 11 tons of water to put out tesla fire!

    Quote Originally Posted by wildernessroadie View Post
    It might not work out practically in the math, but how many BTUs of heat could be dissipated by 20kg of CO2 in a venting heat exchanger? A system by which a constant flow of CO2 is vented around the battery pack? Just spitballing ideas, its probably not practical, but the point is that under certain circumstances there is always a way to design in an added fail-safe to manage an unexpected risk.
    A pack can put out 100,000 watts of power for a full hour. That would take an exceptional amount of CO2 to cool.

    This is a real problem with stored energy vs. fuel. With fuel, a binary energy source that combines some fuel with air, just shut off the air. But when a pack wants to release all that energy you have two options. One, try to get it to not release all of it's energy. Option two -- run, as fast as you can, you aren't going to stop it.

    I daydream about a pack that would use explosive bolts and divide itself up to 8 or 10 packs and scatter them.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •