My LiFePO2 battery caught fire

[deffhaus]

I was really proud of my DIY battery build with headway cells until I stupidly put a cardboard box on top of the batteries not paying attention to the hazard. One of the positive lug bolts pierced the thin film and the cell burst into flames. Fortunately my wife and I were close by and pulled out the burning box and batteries with only small injuries. IT COULD HAVE BURNED MY WHOLE SOLAR BARN DOWN TO THE GROUND!! I took for granted how safe LiFePO2 battery chemistry was and it almost cost me dearly. Attached are photos of the completed battery and the burned batteries (3 total out of my 12 batteries). Note that I’ve circled the lug bolt in yellow to show the source of the error. PLEASE learn from my mistake and consider all battery chemistries hazardous for your DIY project.

 

[Kornbread]

Not sure I quite understand how a cardboard box cause all this, but dang, it looks like you spent a lot of time on the build.

 

[SparkyJJO]

Not sure I quite understand how a cardboard box cause all this, but dang, it looks like you spent a lot of time on the build.

My guess is it didn't directly cause it, but the weight pushed the bar down that caused a high current short, and it then provided flammable tinder.

 

[hankcurt]

Sympathy on the damage to your system. Glad it didn't cause damage to your barn.

Thanks for sharing the pictures and the description of what happened. It appears to be a good lesson in being cautious about keeping electrical connections properly insulated from other parts of the system.

Am I correct that on the Headway cells, the body of the cell is electrically part of one of the terminals?

 

[Shimmy]

Clear packing tape is semi-conductive, not sure if that was the issue or not, but something to watch for.

 

[Substrate]

Wow - thanks for sharing the pics. That diy angled connection is totally precarious. Owners of something similar would be well advised to put a rigid insulator between it and the cells.

Luckily those are LiFePO4 batteries - had they been any other form of lithium (such as with cobalt, etc), you wouldn't have been able to get near them to drag away - it would have been just a molten fireball about 10 times worse.

That's why if you DIY especially, play the "what if" game after admiring your handiwork. Like "what if the metal shelf above my exposed contacts falls down?" That kind of thing.

Again - glad it didn't get any worse..

 

[upnorthandpersonal]

Moved thread to "up in smoke...". By the looks of it, a high current short, and maybe some leaking electrolyte fire. If this would have been NMC there wouldn't have been anything left to identify this as a battery.

 

[Goboatingnow]

Moved thread to "up in smoke...". By the looks of it, a high current short, and maybe some leaking electrolyte fire. If this would have been NMC there wouldn't have been anything left to identify this as a battery.

All high current batteries can cause fire irrespective of chemistry.

 

[upnorthandpersonal]

All high current batteries can cause fire irrespective of chemistry.

Of course, but a high current short in NMC also leads to thermal runaway, which is not the case for all chemistries.

 

[Mattb4]

Tragic loss. Thanks for being willing to let others know about it. It is stories like this that prompted me to buy and mount a fire extinguisher in a handy location to my system. I however should also add a smoke detector and CO monitor close by.

 

[rhino]

I think what he is saying is the weight of the box pushed that positive lug down to directly contact the cell below it and whatever protection on the cell itself failed as well.

 

[rhino]

Tragic loss. Thanks for being willing to let others know about it. It is stories like this that prompted me to buy and mount a fire extinguisher in a handy location to my system. I however should also add a smoke detector and CO monitor close by.

If you are in the USA it was really difficult for me to find CO2 extinguishers.. Called multiple local places including welding supply and they would have to order it. I finally came across https://fireextinguisherdepot.com (which I found after I ordered one from uline for much higher price). Passing along if anyone else having trouble finding them in their area.

 

[Goboatingnow]

If you are in the USA it was really difficult for me to find CO2 extinguishers.. Called multiple local places including welding supply and they would have to order it. I finally came across https://fireextinguisherdepot.com (which I found after I ordered one from uline for much higher price). Passing along if anyone else having trouble finding them in their area.

Common Class ABC foam for LiFePO4 with non flammable gas is entirely adaquate. For others like NMC etc Class D is better

 

[rhino]

Common Class ABC foam for LiFePO4 with non flammable gas is entirely adaquate. For others like NMC etc Class D is better

Yes but then you have a mess to clean up from the foam itself.

 

[curiouscarbon]

thank you for sharing this.

sorry that you lost hardware, but also glad that further loss was avoided.

cheers

 

[chess-equality]

I think what he is saying is the weight of the box pushed that positive lug down to directly contact the cell below it and whatever protection on the cell itself failed as well.

Aren't cylindrical cells supposed to be like AAA batteries and sturdier than prismatic cells? On photos it looks like you can make a baseball bat out of them.

And what was the weight of the box?? SMH...

 

[SparkyJJO]

Yes they're sturdier, but if the outer casing is negative polarity, and that bracket that pushed into it was positive, (or vise versa, I don't know which way it is) you'd have a direct short when it poked through the cell's outer wrapping.

 

[chess-equality]

Ok, but OP said the positive lug bolt pierced the cell underneath. And there were 32 of them and can't hold a cardboard box...

Some of them, looks like were built like a tank:

GenericABCDEFG Headway 38120HP LiFePo4 Super High Power Battery Cells 8 Pieces Pack

Buy GenericABCDEFG Headway 38120HP LiFePo4 Super High Power Battery Cells 8 Pieces Pack at Amazon. Customer reviews and photos may be available to help you make the right purchase decision!

www.amazon.com

 

[SparkyJJO]

He circled the problem in his second picture. The bracket is at a right angle and floating the threaded hole right over the side of the cells. A long enough bolt through there will tear up the cell wrap.

 

[rdhood]

He circled the problem in his second picture. The bracket is at a right angle and floating the threaded hole right over the side of the cells. A long enough bolt through there will tear up the cell wrap.

I think what people are saying is that an empty "cardboard box" did not do that. I'm pretty sure I could put a refrigerator box on that and it wouldn't bend or bow at all. Now, screwing too long a bolt on that such that it pierces a cell is completely possible. But a cardboard box?