Puffy lipo

[meepmeep22]

Hey guys
It seem that I am dealing with a puffy lipo, I have an 8cell Zippy lipo, which seems to have the puffs.
Each side of the cell is ballooning partially, but not very significantly.
What do you think I should do? The battery it self is healthy, Each cell is at 3.8 volts.

 

[whatever]

hi roadrunner
pin prick it, let gas out, squeeze excess gas out, put sticky tape on the hole. Could be hydrogen gas, so put flame near it. Do in well ventilated area in case any hydroflouric gas in there also.

 

[DAND214]

hi roadrunner
pin prick it, let gas out, squeeze excess gas out, put sticky tape on the hole. Could be hydrogen gas, so put flame near it. Do in well ventilated area in case any hydroflouric gas in there also.

NO!

 

[meepmeep22]

hi roadrunner
pin prick it, let gas out, squeeze excess gas out, put sticky tape on the hole. Could be hydrogen gas, so put flame near it. Do in well ventilated area in case any hydroflouric gas in there also.

NO!

Ive heared storys of people pricking lipos and them instantly turning into a blowtorch. What should I do?

 

[nutnspecial]

lipo is the most dangerous 'mainstream' battery tech. I laid it on the line and did a little experimentation when I had the same occurance as you.
Your lipo will never be the same after some of the necessary elements turn into gas, and I'm not fully aware of why this happened to mine. Only thing I can think of is an exceedingly fast charge, or a 'bad' cell in my case.

This is the thread about depuffing them I was following. Nonmetallic pricking should be okay, if you want to continue running a potential substandard and questionable cell.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=22650&hilit=+lipo

I didn't even get that far though, just messed around with a potential/near dead short, and it depuffed, and has been acting normally with 7c draws and 1.3c charges. [youtube]yreU3vrN_5o[/youtube]

Good luck sir, and godspeed lol.

 

[amberwolf]

I have an 8cell Zippy lipo, which seems to have the puffs.
<snip>
The battery it self is healthy

Contradictory statements above.

Puffy = not healthy. (opinions vary on that, however)

Fixable? perhaps, but I wouldn't use it.

BTW, since your battery question is posted outside the Battery subforum, where more people are likely to answer it, would you like it moved there?

edit: nevermind, I see you posted two threads for this, so i've merged this one with the other.

 

[Alan B]

I have seen slightly puffy cells that worked fine, but I would proceed with caution. Cycle them gently on a good charger that keeps track of amp hours discharge and charge, and maintains balance. Assume they might vent to flame and handle the testing appropriately. If you have concerns or cannot handle the safe testing then discard them safely.

 

[meepmeep22]

I have an 8cell Zippy lipo, which seems to have the puffs.
<snip>
The battery it self is healthy

Contradictory statements above.

Puffy = not healthy. (opinions vary on that, however)

Fixable? perhaps, but I wouldn't use it.

BTW, since your battery question is posted outside the Battery subforum, where more people are likely to answer it, would you like it moved there?

edit: nevermind, I see you posted two threads for this, so i've merged this one with the other.

The cell is nice and stiff, But it is a bit puffed, Its preformance is fine tho, what you would expect of a 8c 5.8 amp hour battery. Are there any major dangers of a puffed lipo?

 

[KINNINVIEKID]

So if you follow Dnmuns oft repeated advice to put your packs in compression with hardboard how would you know if you have a puffy cell(s)?

 

[dogman dan]

Slightly puffed is more or less normal for a lipo IMO. It's not good, and you should try to compress the pack some, until it does puff so much you do need to retire it or compress it.

Danger of keeping it in use? What made you think a perfect, unpuffed lipo was safe?

Of course, stop using it when it looks like a blown up rubber glove.

Stop using it immediately, if it's getting all hot after discharging it when the other packs don't.

 

[neptronix]

Compressing a pack is not something i recommend at all. That puffing is a sign of internal stress, and the ability for the cell to puff is a way for the cell to relieve stress without exploding and producing huge flame height.

I have never compressed my packs in all these 5 years i've been using them and my packs have lived a long time and still produce great power and capacity.. no need to do it.

If it became puffy because you were getting it too hot ( running it at very close to it's maximum continuous discharge rate ), then there's no fixing these packs. They will just get worse over time if you continue to get them hot and run them at the same load.

 

[Ykick]

My experience is that Zippy brand generally puff more than Turnigy.

If IR is still decent there really isn’t a major problem with mild puffing IMO. But should it get much worse it runs a very real risk of distorting enough to potentially short tabs at the top of the cells.

Obviously, that could be a very bad thing and can happen laying around in storage not even connected to anything.

I’m not much into the pricking cells to vent them although I’ve done it and everything worked out. But the bottom line comes back to if it get’s drastically worse?

You said they’re springy so I guess IR is ok so maybe wrap ‘em in some of that fiber reinforced packing tape (layer of clear plastic wrap underneath) and store them in a place you can build a fire? Only use them cautiously from here on out.

 

[Alan B]

Puffing means some gas has been produced from the chemistry. If this was an 18650 cell you would not know it had puffed as it would release the gas without notice. By itself it doesn't tell the whole story. That's why testing and careful observation are needed. To see if there are other signs of more serious difficulty. If it has good capacity and handles charging and discharging without getting excessive internal resistance for a few cycles then it may be fine. Four year old cells may already be near the end of their life. Not having cycled it means there is no history to analyze for trends.

 

[dnmun]

i have had puffed nanotech pouches lose some of the volume when put back into compression. but i have no idea what your pack looks like so not sure how you could put it into compression. i put a block of wood on the outside and used a wood clamp so the pressure was spread evenly across the surface.

unless you have some sorta glue or sealant that does not dissolve in the electrolyte it is terminal to puncture the pouch imo. but i used nail polish on a ping pouch once and it seemed to seal it.

 

[neptronix]

My experience is that Zippy brand generally puff more than Turnigy.

My experience with zippy packs is the same. The reason is that they are overrated in C rating by a factor of 2.
I had 20C zippy and 20C turnigy.. the zippy would produce about half the voltage sag and get hotter under the same load. IR on the zippy was double of what it was on the turnigy packs... case closed.

Puffing usually happens when you're pushing a lipo too far and it's generating too much heat internally. You can correct this by dialing down the amps on your controller or adding more packs in parallel to make up for the weakness.

 

[Alan B]

I would expect that mylar tape would be able to seal a pinhole made in a flat surface of the pouch, but I have not tried it. The compatibility of the tape cement with the electrolyte would be the question. I have read that people use scotch tape, though that is very weak. The pouches being mylar would indicate mylar tape might be good.

 

[whatever]

I pin pricked 3 cells today, you just need to prick the mylar , you dont stick the needle right into the internals of the cell!
Once the cell is expanded the plastic pouch will never go back to completely flat, it will still have wrinkles in it, but you wont have the gas in there anymore ( which is dangerous as its hydrogen. I've never had any problems with the procedure. I've got some cells here which I took off all the outer plastic pouch and wrapped in wide sticky tape, the electrolyte has not reacted with the sticky tape in any way. One cell has been sitting there for many years and theres no reaction with sticky tape with the electrolyte.
Dont hammer a pin right into the cell, just prick the outer plastic where its not touching the internals, somewhere in the middle of the bulge. Just slide your fingers towards the pinhole you get most of the gas out. Wear gloves if your worried about it.

 

[meepmeep22]

I pin pricked 3 cells today, you just need to prick the mylar , you dont stick the needle right into the internals of the cell!
Once the cell is expanded the plastic pouch will never go back to completely flat, it will still have wrinkles in it, but you wont have the gas in there anymore ( which is dangerous as its hydrogen. I've never had any problems with the procedure. I've got some cells here which I took off all the outer plastic pouch and wrapped in wide sticky tape, the electrolyte has not reacted with the sticky tape in any way. One cell has been sitting there for many years and theres no reaction with sticky tape with the electrolyte.
Dont hammer a pin right into the cell, just prick the outer plastic where its not touching the internals, somewhere in the middle of the bulge. Just slide your fingers towards the pinhole you get most of the gas out. Wear gloves if your worried about it.

Thanks, Just to be on the safe side, I think I am just going to let if be for now, The puffing is not very severe, as I said before.

 

[ddk]

...I forgot to take a pic, but my puffy pack looked like a party balloon.

I stuck mine in a fridge and it got all like, un-puffy deflated-like without the pinprick.

AFAIK... depending on ambient temps and other factors, very slight puffy-ness comes and goes and is the nature of these flexible bagged batteries.
However, they shouldn't try to mimic a party balloon.

 

[dogman dan]

Lotsa disagreement about what's puffed. But I think we all agree that a very puffed pack is toast. Like party balloon puffed. If it puffs enough to split the shrink, dump it. Packs I had that did that were clearly defective. They arrived that way, or got that way in less than 5 cycles.

It will still work de puffed, but I call it dangerous by then. And a severely puffed pack de puffed will have very low capacity.

But slight puffing, like a 5 s pack is 3mm bigger, that can be used. It can help to compress it some at that point, but then if it continues to become a party balloon, it will split and leak. I keep mine in a tight fitting coroplast box, which provides me a slight squeeze on them, but not a true strap down.

Some very slight puffing is pretty normal for the turnigy or zippy packs I've had. Contrarily, my zippies seemed to puff the least. But a very slight puff after about a years use seems routine, and none of mine puffed significantly more, even after years later. But once they do puff slightly, forget much more than 70% capacity, and they will soon be down to even less, unless you discharge them at .5c.

 

[ddk]

For your amusement...

I find it curious that so far, only my unused cells are failing in this manner.

 

[Alan B]

It is interesting. Cycling cells does change them. Perhaps the early forming on these cells was not sufficient. I have seen some recommendations for cycling lithium cells when new, but most sources say this is not necessary. In this case it seems to be important.

 

[dnmun]

the 8Ah nanotech pouches that i had swelled without having ever seen use. i had built a 24S lipo pack with them for silverheels and they sat on my table for a long long time because he disappeared.

never used, just charged up and let sitting at full charge. this was long before i understood how damaging it is to leave lipo stored at full charge.

those pouches were still inside the shrink wrap because that is what silverheels wanted so after i realized how swollen they appeared i took them apart and put the 6S packs into compression with my wood clamp and left them clamped for several weeks and eventually much of the swelling seemed to be gone.

i eventually took all of those apart and used them in my 21S lipo pack for my car but after i used the battery for awhile i realized that i had dead, self discharging pouches, in the middle of my pack so i had to take the entire pack apart and isolate which pouches were bad in the middle of the 21S3P 8Ah nanotech pack. i ended up removing about 7-9 of the pouches from the pack. all of them were from the batch that silverheels had given me and i had no other failures in the many other 8Ah nanotech packs i bot to add to these to build the battery initially.

so i further examined which ones failed and i recognized that the 1st pouch in each of these 6S packs had failed and ended up with a swollen head at the top of the pouches. i called them hammerheads. all were dead and self discharged to .1V or so eventually.

as you know, HK solders these huge 10AWG silicone wires to the ends of each pack. the only pouches that swelled and failed were the #1 pouch in each of the 6S packs that silverheels gave me. which may be why he never wanted them after since he had another 24 he used on his bike and had problems with them.

i am certain that the reason these pouches swelled up and self discharged is because the heat from soldering the huge wire to the copper cathode of the pouch. i think the heat conduction into the pouch during the soldering step was sufficient to severely damage the current collector and electrodes and caused the cathode to grow whiskers or just failed because of the heat presented during the manufacturing.

this is why i recommend that people do not solder large wires to the case of these 18650 cans. i have told many people to use the tiniest of tiny little copper strips to make the serial connection and to solder along the very outside edge of the can if they solder. i also have warned people to not spot weld to the middle of the bottom of the case for the same reason. nobody ever followed any of that advice.

 

[meepmeep22]

Little update. Accdently left the controller on with that battery , It now feels like a peice of warm butter.

 

[neptronix]

If a pack is swelling without any use, it is internally damaged from the factory and it's a ticking time bomb.

Do not play with known imperfect lipos, unless you park your bike in a concrete cave or something and have some kind of shield to prevent a massive fire happening starting at your crotch while you ride it.

These are literally the most dangerous and flammable batteries ever sold to the public. Your risk to reward ratio with a damaged pack is very, very low.