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Safely housing the battery bank
#21
Lithium battery that has gone thermal and spewing sparks can create a LOT of heat, especially in the direct path of the "torch".

Plugging the ends where the cells would be housed would be like putting a fire cracker inside a paper tube. It'll build up pressure and cause a large explosion. The best way is to let the cell vent somewhere/how safely. If the cells are in a pack and they lay down horizontally, then the Pos end facing a flame retardant barrier would be best.
An idea you could do is have another pack/wall built from small metal tubes. Then on the backside of the tube-pack could be an open chamber that vents outside. Then place the tube-pack right up against (without touching) the battery packs. If a cell goes nuts, it'll flame into the tubes which help to dissipate heat and direct the flame/chemicals/flying bits away from everything else and to outside.
Proceed with caution. Knowledge is Power! Literally! Cool 
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#22
CO2 will NOT work to extinguish a lithium-ion fire, since during thermal runaway, the cells supply their own oxygen.

You need to make a sand pouch which will open during excessive heating, or just spray with water and pray you can recover some cells.
The power of lithium ion is in our hands!
We'll show them what we're made of!
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#23
I was thinking about something like this....
Tubes also crossed my mind.
Pvc tubes that a electrician use, I am in doubt.
To cut thin steel tubes is a hassle for some or order somewhere.
I think the foam will let its self spit out easy.



Sensed with my phone

A sand bag would be very good, better than water.
But if the bag is going to do his job, wouldn't he close in that one cell, so we get a firecracker?
Or the sand can not reach that one cell (cous of the fountain?)and protect the others?

With the foam, fire resistant that is, will protect the other cells, that one cell is lost anyway.
Only the time that a cell is burning worries me, would the heat be enough to light up his neighbors?
Again sand seems to be the option.

But: The tubes, i like the idea more and more, got some idea's spinning in my head right now.

I am more at this point to save the rest of the cells, or am i missing the point? be honest please.
Or is the whole pack wasted?
Then we are going to look for rescuing the other packs, and that is pretty simple to do.

with all three the solutions the packs have to be on a shelf on there side, to let the sand in and direct the flames away from the other cells.

I want to come up with a simple workable solution, all the ideas that where given i will make projects out of it.
thanks for the good ideas and help!!!very appreciated.
Materials enough, room and machinery also.
If one! cell can ignite 14000 (not going to stop there, ev's are coming and the house) other cells, than i want to be save as possible.

Without adding heat, how do you trigger a cell?
Got heaters enough, charge them with 8v or something?
Like a real life test, when your fuse is 20 amps instead of your regulair 1 amp, factory mistake or something, give it a name.

Thanks in advance for all the help AND ideas, keep them coming, with best regards, Igora


The missing picture, sorry for the goof up
Still learning English. Learning Li ion and solar technology.

4200 cells in packs Exclamation above 2500mah and 90%soh.
1500 waiting for testing.

Saving for 3 times phoenix inverter 48/3000 230v to gain also 380v
3 chargers?

Time is our enemy, must work to, the sun is our friend, must relax to.
With best regards
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#24
Found this real-world example of some guys that overcharged a Tesla battery.  Shows cascading, fireworks burn.  
Here's a snapshot near middle of the youtube - see @Rich Rebuilds "My first Tesla Battery Fire"  Nov 23, 2018.
 

This is what a battery box would have to protect against  Exclamation
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#25
That garage video made me think about safety....oke there was a ? what 5 kwh?

I am planning to build a minimum of 100kwh.
Good luck if just one will go rogue/a wall, bad guy, what ever...and we have a chain reaction...
Fuses, bms ect can not protect everything, what if that one cell at 28.000 cells, what if....

thanks for your thoughts and ideas! keep them coming please

vid also

Foam didn't work, was to firm in the hole, +1 for Korishan!
Still learning English. Learning Li ion and solar technology.

4200 cells in packs Exclamation above 2500mah and 90%soh.
1500 waiting for testing.

Saving for 3 times phoenix inverter 48/3000 230v to gain also 380v
3 chargers?

Time is our enemy, must work to, the sun is our friend, must relax to.
With best regards
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#26
I have read a lot of the recent comments and think you may all be missing one vital point to take note of....

The release valve in an 18650 cell is set to operate around 145psi and a little bit of sand is just going to blow away quite easily (while preventing convection cooling prior to the cell overheating, adding to the likelyhood of a cell overheating). A thin sand boundary between cells could work to prevent a cascade, at the expense of convection cooling so consider the nissan leaf battery issues with just air cooling and then imagine removing the air cooling.

The reason the cells ended up on the garage roof in the video is the pressure released when the valve burst, sent them off like rockets. Hold a bunch of 18650 cells really tight together and you may find that the pressure from a single cell moves part of your pack, shorting out other connections (as some powerwalls are not fixed and just stacked into frames). Stack packs with caution....

If I were to build with 18650's it would either be a small pack for a purpose, with an understanding it may catch fire. For a powerwall build, space the cells out to allow convection cooling and help preventing a cascade with the packs fixed in place to prevent them falling over if one cell was to push with 50lb force.. The plastic cell holders I think are too close together and don't have a lot of room for unforced convection, which maybe ok at 0.5C. They are cheap to make because they tightly pack the cells in and use less plastic, which also adds to the fire risk...

Option : spot weld with thin metal strip one side (multiple layers welded on top for higher amps) so the cells are spaced out and then solder the tops, using the fuse/wire for minimal support and stand the cells vertical on the spot welded strip and not horizontal (as in most powerwalls I have seen). Lot of other issue without additional suppor on the top though if mobile for example...

Just though the burst pressure is a missing consideration.....
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If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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