Fantastic job! An important video, very well done.
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So. Many. Things. Wrong.
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For anyone intrested, usually when making a market approved battery pack(lets say a forklift lion battery), one of the basic validations is letting one single cell run rampage to see if the failure propagates onto other “good” cells in the pack. If it doesn’t then the design is approved. If it does, its back to the drawingboard.
Applying this process to our own packs would be ideal but obviously alot harder to do.
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And with nickel strip forcing the hot ejecta sideways, onto other cells instead of letting it all shoot away from the pack, it makes passing cell-to-cell runaway propagation testing that much more difficult. 
Packing the cells so close together and blocking the operation of bottom vents (for cells with them) can help runaway travel from cell to cell too.
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with cells sitting literally right next to each other, its gonna be impossible to do right?
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haha yeah exactly, which is hard to avoid for us if we conserve space 
at work we use ultrasonic wirebonding f.e 
creates very small area of obstruction. wonder if that can be a handheld device somehow 
Our chem engineer says water is good, not cause its puts out the fire, simply because it cools the cells down, preventing boiling of electrolyte. But yeah, you’d likly have to submerge it.
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In the case of our flat packs, yea not sure how that would get done properly. theoretically on topmount mountainboard pack, its definiatly possible to accomodate tho.
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Yup, water (or an aqueous firefighting solution) is probably the best method to fight a li-ion cell/pack fire. It cools the cell down to below the thermal runaway threshold temp, between 130°C and 270°C or so depending on the cell chemistry.
The electrolyte boils at around 80°C and isn’t as much of a concern compared to the violent, exothermic runaway reactions in the metal-oxide materials used to make the positive side battery goop.
Submerging would be my vote.
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The bag survived surprisingly well in that vid. if it prevents the cells from becoming rockets, that is a gain in my book
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NASA has some great cell/pack safety workshop PDF’s that show some of their testing. Spacing between cells is good but something like a thin lattice of aluminum spacers (to spread the head out) or graphite spacers can work wonders to stop the fire from spreading…if we stopped using fat nickel strip on the top and bottom. 
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Agreed, preventing cells from rocketing everywhere and starting more fires is important.
IMO, add a good handle to either end of the bag and make it something to survive just long enough to toss the bag outside. Nothing will block the toxic smoke and gases so you want it outside ASAP anyway.
Though some seam reinforcing and a directional vent is recommended.
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that bag wouldn’t have exploded like that if it had some small vent holes or some kind of mesh vents, and It may have actually contained the flames and just burned internally. If they really did reinforce the seams it’s just going to make a more violent explosion of gasses like Mario said.
i’d rather have a room full of toxic smoke than a house fire if i have to choose between the two. If the windows and doors aren’t on fire, i can open them.
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Reinforce the seams but have a directional (tubular?) vent. The good seams ensure that the vent is the only way that the smoke/gases can exit the bag. This keeps everything out of your face as the bag is dragged outside.
As Mario noted, the smoke/fumes are like being pepper-sprayed and are incredibly dangerous to breathe too.
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Yeah i was thinking a combo of reinforced seams and some kind of vent mesh on one side to let pressure escape.
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A little research and the bag manufacturer could ensure that a mesh opening would also act as a flame arrester, helping to keep the electrolyte from igniting or at least speeding up its quenching.
I think it involves a couple of metal mesh layers with the proper opening area size and spacing between mesh layers?
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LOL…all this makes me want to bring a great bag to market. Not merely “fireproof” but Mario Proof. 
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These guys did pretty much just that
Metal case, fire proof internal lining, meshed holes with filter.
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Aim high I say 
Edit: I would love to see you do a guest appearance on the next fireworks video @Battery_Mooch ! The Mario wank bank is getting a little stale
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