De-Puffing Turnigy Lipo Cells

I had 4 x 22v packs that have been accidentally overcharged cellls to 5 volts
they have been sitting on my workbench for around 8 months i guess, i thought
i would salvage the cells still good today since i have stalled waiting for parts on
my 2 speed cruiser build I have also been asked about how i go about releasing (de-puffing) the gas from individual puffed lipo cells that have been over charged, by a handful of people now, so rather than explain it i
have made a small video showing the procedure i use. Nothing fancy, i HIGHLY recommend
though NOT using anything conductive like i show in the video a tooth pick is perfect
for this, you only need a small 'prick' to release the gas, you absolutely
don't want to press the pack too hard that fluid is released, you want just the gass out.
You can prolly gauge the pressure i apply in the vice, the lipo cell drops
from the jawz of the vice soon as the gas is released.

[youtube]ZcR8tDgiIeE[/youtube]

Now, I don't need a lecture on how "dangerous" this can be i am fully aware of the dangers of
lithium polymer, that said... I have been using ~12 de-puffed cells in my 44v 20ah pack now
with great success for the last 6 months, the capacity of the cells isn't noticeably different and
they all remain well balanced, PLEASE NOTE these are the new
Turnigy cells from HobbyCity NOT old no name brand lipos from years past
i would HIGHLY recommend not trying this on any old lithium polymer packs...

Hope this has been informative anywayz...

KiM

The gas is highy toxic and flamable by the way. So take em outside for the initial pressing. Once you get the first fart out in the wind, then bring em inside to put on the vise and seal up.

My puffy packs are doing ok, but not too puffed, and I cover em up with a bbq grill cover to charge, or charge outside. Not that many cycles on em though, less than 20.

You dont want to get oxygen or water vapor in the pouch, so doing it with Kims method is pretty good.

Definately for the bold only, but from Kims pioneering work in doing it sucessfully with good long term results, it seems to be a viable option.

I must try this next time I have a puffed cell.
The first time I did what anyone new to lipo does...
Poked a few big holes in it

One thing I wonder is hot melt really the best glue to use?
I assume it is good in that it seals the hole quickly keeping in as much solvent as possible but I wonder about long term stability.
Could it be covered with something more durable once the hole is sealed?
I know there is a higher temperature orange hotmelt we use to use at a former place of work that set much harder and stuck really well but not sure where to buy that stuff.

Ricky_nz said:

One thing I wonder is hot melt really the best glue to use?
I assume it is good in that it seals the hole quickly keeping in as much solvent as possible but I wonder about long term stability.

Click to expand...

It seems to be holding up very well, the trick i believe is to lance/pierce your cell right on the crease line of the seal
of the cell, you then have the glue sealing the hole and it also glues the over lapping seam/flap down in the area your make the cut providing that lil bit extra security
.
What i also do with all my packs is wrap them 4x times as tight as i can with kevlar tape, it is near zero stretch tape, i then assemble the pack and again wrap the entire pack with 4x wraps of kevlar tape before connecting the pack up in my fiberglass highly flammable container for charging :wink: I shall keep the forum updated on any changes etc, but thus far after dozens of cycles they are performing as they should... Best of luck if you give it a try anywayz

KiM

AussieJester said:

Ricky_nz said:

One thing I wonder is hot melt really the best glue to use?
I assume it is good in that it seals the hole quickly keeping in as much solvent as possible but I wonder about long term stability.

Click to expand...

It seems to be holding up very well, the trick i believe is to lance/pierce your cell right on the crease line of the seal
of the cell, you then have the glue sealing the hole and it also glues the over lapping seam/flap down in the area your make the cut providing that lil bit extra security
.
What i also do with all my packs is wrap them 4x times as tight as i can with kevlar tape, it is near zero stretch tape, i then assemble the pack and again wrap the entire pack with 4x wraps of kevlar tape before connecting the pack up in my fiberglass highly flammable container for charging :wink: I shall keep the forum updated on any changes etc, but thus far after dozens of cycles they are performing as they should... Best of luck if you give it a try anywayz

KiM

Click to expand...

All the pressure you can get on them is great for the cell. As the layers get closer, Ri drops, and everything works better.

I put a cell in a large vise, was putting all my weight on the handle, then hit the handle with a sledge hammer to squeeze it tighter, and still it wouldn't short through the seperator layer, so I think it's safe to put some squeeze to them.

Thanks for putting that together, Kim, it's nice to know that all's not lost if a cell or two get puffed.

I've just put a pack of LiPo together using non-stretch glass reinforced packing tape and it seems to have worked well. I first wrapped the cell pack with a thin layer of closed cell foam (about 3mm thick) then pulled the tape as hard as I could around the whole pack. I'm hoping that the pretty stiff foam will help to keep a fairly even pressure on the cells. I'm pleased with the way this tiny (10S, 2P, 37V, 10Ah total) pack has come out. I'll post details on another thread when I finished all the updates to this particular bike.

Jeremy

AJ you crazy mofo, i would have at least used some gloves and a face shield lol..

I used some ABS between my packs, gave them the squeeze with a clamp and filament tape to keep them tight.. so far so good. !

That is a supurb way to do it Ypedal.

Thats nice to know you're not necessarily out $50-60 if you get a poofter cell...nice going kim.

Not to tread off track too far: Has anyone here kept track of the cycles on their lipo pack and seen no drop in capacity beyond 1000 cycles?

you used a disposable knife in your video witch is conductive.

you are lucky you did not short the cell causing it to burn.

AussieJester said:

I had 4 x 22v packs that have been accidentally overcharged cellls to 5 volts
they have been sitting on my workbench for around 8 months i guess, i thought
i would salvage the cells still good today since i have stalled waiting for parts on
my 2 speed cruiser build I have also been asked about how i go about releasing (de-puffing) the gas from individual puffed lipo cells that have been over charged, by a handful of people now, so rather than explain it i
have made a small video showing the procedure i use. Nothing fancy, i HIGHLY recommend
though NOT using anything conductive like i show in the video a tooth pick is perfect
for this, you only need a small 'prick' to release the gas, you absolutely
don't want to press the pack too hard that fluid is released, you want just the gass out.
You can prolly gauge the pressure i apply in the vice, the lipo cell drops
from the jawz of the vice soon as the gas is released.

[youtube]ZcR8tDgiIeE[/youtube]

Now, I don't need a lecture on how "dangerous" this can be i am fully aware of the dangers of
lithium polymer, that said... I have been using ~12 de-puffed cells in my 44v 20ah pack now
with great success for the last 6 months, the capacity of the cells isn't noticeably different and
they all remain well balanced, PLEASE NOTE these are the new
Turnigy cells from HobbyCity NOT old no name brand lipos from years past
i would HIGHLY recommend not trying this on any old lithium polymer packs...

Hope this has been informative anywayz...

KiM

Click to expand...

ejonesss said:

you used a disposable knife in your video witch is conductive.

you are lucky you did not short the cell causing it to burn.

Click to expand...

And don't forget rape my family while it burnt my house down, with me in it

AussieJester said:

I had 4 x 22v packs that have been accidentally overcharged cellls to 5 volts
they have been sitting on my workbench for around 8 months i guess, i thought
i would salvage the cells still good today since i have stalled waiting for parts on
my 2 speed cruiser build I have also been asked about how i go about releasing (de-puffing) the gas from individual puffed lipo cells that have been over charged, by a handful of people now, so rather than explain it i
have made a small video showing the procedure i use. Nothing fancy, i HIGHLY recommend
though NOT using anything conductive like i show in the video a tooth pick is perfect
for this, you only need a small 'prick' to release the gas, you absolutely
don't want to press the pack too hard that fluid is released, you want just the gass out.
You can prolly gauge the pressure i apply in the vice, the lipo cell drops
from the jawz of the vice soon as the gas is released.

[youtube]ZcR8tDgiIeE[/youtube]

Now, I don't need a lecture on how "dangerous" this can be i am fully aware of the dangers of
lithium polymer, that said... I have been using ~12 de-puffed cells in my 44v 20ah pack now
with great success for the last 6 months, the capacity of the cells isn't noticeably different and
they all remain well balanced, PLEASE NOTE these are the new
Turnigy cells from HobbyCity NOT old no name brand lipos from years past
i would HIGHLY recommend not trying this on any old lithium polymer packs...

Hope this has been informative anywayz...

KiM

Click to expand...

[/quote]

What I have tried is to:

1) first place a blob of RTV on the edge of the pouch
2) prick the pouch (which has some squeeze on it) with a needle through the RTV. DONT hit the magic stuff in the pouch. It gets VERY angry when you do and tries to kill you.
3) withdraw the needle and let the pouch vent through the RTV
4) right when the pouch if fully vented, smear the RTV closed and let it set.

What this does is minimize the chance of air/water vapor getting into the pack. If you do it right, all the flow is out of the pouch (like a positive pressure air lock) and nothing gets back in.

The more experience I gain working with batteries and understanding the batteries, the more this procedure seems fine to do. Taking the gas out really does fix the problems with the cell, and almost always, the cell has plenty excess electrolyte in the pouch.

It's the sort of thing you could never fully condone, and there is definitely a real risk of botching it and having some flames, however, I would feel fine using cells that has been de-puffed.


The exception to de-puffing a cell would be if it arrives puffed and/or arrives puffed and at low voltage. This means the cell had absolutely has mfg impurities and/or some error inside, and taking the gas out can't fix that problem, it can only relieve the symptom.

The packs to de-puff are the packs that you damage from whatever reason, over-charge, over-discharge, extreme heating, etc. If you de-puff those packs, they really will be in a lot better way afterwards.


*** Disclaimer- Trying to de-puff a pack could potentially erupt intense fire in your face and/or burn your house down, and/or touch your children in there bathing suit zones, etc.

Tons of respect to you guys!

Taking inventory this season I had 4 puffed packs that I really didn't want to completely replace. I would call them moderately puffed-- When the shrink wrap was on you could easily see the puffing

I tried using toothpicks at first but the wood was too soft to pierce the packs, so I resorted to a razor blade. This worked well, especially after I put a little pressure in the vice and the sides swelled up slightly. They deflated almost like a balloon; I could hear a little faint hiss with some cells.



Here was my setup



And them all afterwards



They turned out awesome! I balanced charged them about a month ago to 3.85V. Without touching them since they were all +/- .01V after I de-puffed them. I think of the 24 cells, 6 weren't at 3.85V.

We'll see what capacity turns out to be. I'll do a couple cycles with my hyperion RC charger.

Thanks for sharing Kim.


Maybe i could add one great advice to this method:

Always discharge the cell to be surgered BEFORE attempt to puncture it !

From my experience all times i tried to make some lipo cell to catch fire, it was not possible when the cells was discharged or at lower voltage than the LVC.

On the opposite... try puncturing a lipo cell when it is charged ! you will see the magic smoke and then fire!

So please discharge the cell before atempting this great surgery! :wink:

Doc

Great thread. It worked on lifepo4 rc packs. Although I wasn't able to squish it back to original size. Restored some capacity too. I used hot glue for the hole. I'm stoked.

i used nail polish to seal a hole i accidentally punched into a ping pouch. it never leaked. conformed and coated the surface very tightly. i think the acetone in the nail polish gives it a cleaned surface to adhere to. immune to the electrolytes maybe.

Hhhmm, interesting. I got a stack of Turnigy lipo I over discharged sitting in a metal box, was thinking of chucking them but I might try this one day and get them to become some kind of B-grade turnigy type packs.

I recovered 5 out of 6 packs of my 6s 5000mah Turnigy lipo doing this method, I am very pleased
I am interested in seeing the pics Ypedal posted but there not viewable on the forum any more because there were posted way back in 2010?

All my packs that had dead cells were either the first or very last cell in the pack, (the ones that can most easily puff) also all cells had been discharged to at least below 2.0v the cells averaged 1.2volts I would say.

I used my BC168 charger to recharge the batteries after depuffing them in the vice.
The BC168 appears to not charge a cell if it reads 0volts so I gave any cell that read complete 0 a little voltage kick from another battery and the BC168 instantly kicks in and starts charging the cell.

There was at least one pack where after being in the vice and charging the other cells on the BC168 a bad/dead cell reading 0 just came back to life and didnt need any external voltage boost to kick the BC168 into charging it. It seemed to actually come alive after I removed it from the vice with the BC168 plugged into it and I noticed a voltage reading come alive from zero.
I then started to then gently massage the end cells of this pack with my fingers moving electrolyte juices around inside, I reckon it helped bring the cell healthy and alive again.

I also placed my packs with foam in between the vice the idea is that any pits in the pack get more pressure then just straight hard walls.
I used a Stanley knife to depuff my cells, I tried using a toothpick from Nandos but it didn't work, I then on my last cell tried a blackberry thorn and this did work, so theres another option.



I feel more uncomfortable about using these packs now as I have tortured them so I have placed them in this metal box, there also wrapped in fire-blanket on the inside.
I also placed a fuse switch here that is in between both 6S packs in series, this way I just flick a switch and can plug in both my JST balance cables into the BC168 at the same time to charge the whole pack without creating a short/fireworks. Of course all I have to do is merely flick the switch while the two balance leads are connected and I will be sorry.
I do prefer this method though as constantly unplugging-replugging the two sides of the battery manually just feels crappy.
This box contains 4 Turnigy S6 packs.... so its 12S 2P setup.

i'll try to dig up the pictures and fix the post..

any de-puffed cell should be handled with extra care, and personally, i declare them " grenades with pins pulled " to be charged outside only...

and fyi, the cells i de-puffed are still functional, i use them for testing project bikes and short trips around the block...

Ypedal said:

i'll try to dig up the pictures and fix the post..

Click to expand...

OK cool, looking forward to it.

Great thread, I have some packs I can try it out on. Seems like a needle would be a good way to pierce it. Definitely do it outside or in your garage. If something does go wrong, have a bag of sand to drop over it. The smoke damage if done inside can be extensive. Wrapping the lipo's in fiberglass afterwards would be a good way to recreate the lipo bags you purchase to contain the fire. It smothers the fire if wrapped well. I myself would use a vacuum pump and incase the whole pack in CF and epoxy. This would keep the pressure high and the fire hazard low. I plan to use this CF vacuum seal method on new custom packs. Since trail riding has been quite rough on my packs.

I made a pack with puffed cells. Last weekend I opened it to add more newer cells since I wanted less voltage sag and found where the holes were there are circles on most of the packs. This was after about 30 cycles. I believe this is because the tape I used let gas escape. I would recommend making sure you get it air tight. I am using some e5000 glue with tape on top this time.

http://i928.photobucket.com/albums/ad124/chips2482/IMG_0453-1.jpg~original
http://i928.photobucket.com/albums/ad124/chips2482/IMG_0455-1.jpg~original

I had trouble getting the hot glue to stick to the foil where the acid came out. RTV wouldn't stick either. Had to do one pack over when it puffed slightly. It seems to be ok right now.