Saving or recycling of a lipo pouch cell (tiny hole in exterior wrapping)

[enrengineering]

Hello
On september of last year I was taking apart a battery I bought, the BMS failed (due to overdischarge), I checked all the voltages of each cell and the voltage of the whole pack and everything was ok. I was trying to separate one cell of the whole pack to find out any part number to identify the cells and find the specs/datasheet of the cells to find a new suitable bms. I used a worn out metal spudger (here my mistake) and managed to scratch the wrapping of the pouch cell, nothing caught fire and no smoke was released, I immediately covered the scratching with electrical tape. I kept an eye until now at the whole battery an also the affected cell but nothing changed, same voltage and physically looking the same. I'm asking if I need to dispose the affected cell or if I can do anything to save it. The cells are the LG P2.7 arranged in a 14s1p configuration, the battery fully charged is at 54V and I need a 48V system, most probably if I need to remove the affected cell I can live with the 51-ish volts.

Here's the affected cell and the electrical tape covering the scratch



And here you can see the scratch on the wrapping

Any advise will be greatly apreciated.
Thanks, Henry.

 

[fechter]

I've seen people seal a hole in a pouch cell with some kind of glue and it seemed to work out OK. Not sure what glue would be the best. I would probably try epoxy, but make sure the surfaces are all clean and there is no electrolyte leaking out.

To be really safe, recycle the cell.

 

[DingusMcGee]

I have used a good grade of hot glue from the warm gun — happiness.

 

[Lucifer]

Hello
On september of last year I was taking apart a battery I bought, the BMS failed (due to overdischarge), I checked all the voltages of each cell and the voltage of the whole pack and everything was ok. I was trying to separate one cell of the whole pack to find out any part number to identify the cells and find the specs/datasheet of the cells to find a new suitable bms. I used a worn out metal spudger (here my mistake) and managed to scratch the wrapping of the pouch cell, nothing caught fire and no smoke was released, I immediately covered the scratching with electrical tape. I kept an eye until now at the whole battery an also the affected cell but nothing changed, same voltage and physically looking the same. I'm asking if I need to dispose the affected cell or if I can do anything to save it. The cells are the LG P2.7 arranged in a 14s1p configuration, the battery fully charged is at 54V and I need a 48V system, most probably if I need to remove the affected cell I can live with the 51-ish volts.

Here's the affected cell and the electrical tape covering the scratch

View attachment 331692

And here you can see the scratch on the wrapping
View attachment 331693
Any advise will be greatly apreciated.
Thanks, Henry.

I am so new to this that you should ignore me..... BUT, I happened to have googled puffed cells and in particular making a microscopic hold in the pouch and fixing it. The info I could get was that once punctured the cell ALWAYS fails, apparently even introducing a small amount of air frocks them up. Don't rely on me but google that yourself, because we all know what cell failure can be like (in a worse case scenario).

Keith

 

[floydr]

I'm asking if I need to dispose the affected cell or if I can do anything to save it. The cells are the LG P2.7 arranged in a 14s1p configuration, the battery fully charged is at 54V and I need a 48V system, most probably if I need to remove the affected cell I can live with the 51-ish volts.

Is there a sickly sweet smell coming from the cell? if so you need to remove and dispose of the cell. IF no smell Probably ok to seal with epoxy.
14s @ 100% soc 58.8V., 51.8V nominal.
13s @100% soc 54.6V, 48,1V nominal.

Later floyd
edit: I agree with nicoble it isn't worth the risk.

 

[nicobie]

I wouldn't take the chance. But hey, that's only me.

Think about the risk. It's yours to take.

 

[Lucifer]

Interesting, what about slightly puffed cells, that appear to test ok? I was going to recycle them (dispose of) but really hate waste. What do you think of these (I have a fair number).

Keith

 

[Lucifer]

Yeah I had reluctantly decided to get rid of my slightly puffed cells, I read somewhere else that someone tried a needle and immediate repair, but he said while it looked like it worked at first that the cells always failed soon after the fix, he said every single one failed, so he gave up trying, but then seeing this thread at first I thought, I would of kick myself if I got rid of them then found I could of fixed them. But I'm, back to disposing of mine,

Keith