Puffing A123

[redstone02]

Hello,

I have a puffing A123 in a fairly new battery pack from Victpower (http://endless-sphere.com/forums/viewtopic.php?f=14&t=43887#p639447 ).
Wondering what to do, if anything.
Can the cell be vented?
Should I just leave it be?
Should I take any special pre-cautions for this puffed cell?

This battery pack has been a hugh POS. Bad BMS, connection on postive output came off, now this.
I got a settlement from Victpower for the bad BMS so the $$$ hit was not that bad, but this is getting to be a pain for such a young pack.

Thanks for any help and/or ideas.

Tom

 

[dnmun]

does the pack have BMS now? what is the voltage on the puffer? do you have a picture? did it puff when the BMS went bad?

 

[redstone02]

does the pack have BMS now? what is the voltage on the puffer? do you have a picture? did it puff when the BMS went bad?

Yes, the pack has a BMS from BMS Battery (http://www.bmsbattery.com/bmspcm/323-17s26s-24a-max-discharge-current-bms.html )
Will check voltage in just a moment. Thanks for the reply dnmun.
Tom

 

[redstone02]

The puffing cell is an end cell; cell #16 as wired to BMS.
The voltage of the puffing cell is 3.39 v. This is after setting around for about 4 weeks while new BMS arrived.

Overall cell voltage for pack, cell #1 to #16:
3.34 cells #1 - 6
3.52
3.5
3.34
3.34
3.35
3.34
3.34
3.34
3.51
3.39 (the puffer)

Regards,
Tom

 

[K-ray]

Hey Red,

Sorry to hear of your misfortune... :? It seems the end cells in packs have been most likely to puff lately.
Do you have any compression designed into your pack? Seems this should be a MANDATORY requirement
for these 20Ah pouch builds?
Good luck with the fix... I noticed a couple of "local" ebay sellers offering cells reasonably priced
If you do decide to replace this one I'd be interested in your puffer (will pay shipping). I have a nice IR analyzer
in transit to me and some experimenting of values prior and post venting / compression would be cool.
Let me know 8)

K

 

[circuit]

Voltages do not say anything.

Charge at slow rate (1A or so) until all cells are fully charged and sit at 3.65V. Disconnect the BMS. Let it rest for a month. The swelling will go away slowly.
Keep the pack in fire-resistant environment.
When swelling goes away, it does not mean that cell is ok. So do not expect it to perform as new. But anyway most of victpower cells have been puffed at least once while sitting somewhere in china, so it might not stand out from others.

 

[dogman dan]

A lot will depend on how puffed. If lightly puffed, you might be able to prick it with a non metallic point, vent it, then reseal the pack with some kind of glue.

The depuffed cell might then be ok, or might be ok only for awhile. Might be a solution only to get you through till you can aquire some more cells.

If really puffed, I'd call it junk and replace it.

 

[dnmun]

i have not found glue that will seal them. they always leak afterwards. the best luck i have had with sealing the mylar is using nail polish. the nail polish i found was clear and was for hardening nails. it seemed to stick better. have not seen it leak yet, but i think that spot never was punctured so it did not have solvent from the electrolyte eating at it.

not much you can do i think. maybe it will shrink with sitting, but i doubt it. all the puffers i have seen never go back from sitting. you gotta keep it charged though. the cells should all be at 3.65V when on the charger and fully charged. 3.34 doesn't cut it. jmho

 

[redstone02]

Thank you for the help.

The maximum discharge rate has been 20 ampere (20 ampere controller). I ran the pack through four discharges/charge cycles to break in the pack while building the bike. There were several water heater elements in my "junk box". These were cobbled together for a switchable load bank; six stages ranging from ~6 ampere to ~18 ampere. The discharge/charge cycles were not run back to back, + several days between cycles. The charger is only 5 ampere. So, to me, the pack has been gently used. The "puffer" is now 2X normal thickness, gaining 100% width.

Thank you for the reply Circuit. The discharge/charge cycles I ran the battery pack through closely mimic your recommendation. The rest time between cycles being only one to two weeks. Over this course of these discharge/charge cycles is when the puffer puffed.

All the Best,
Tom

 

[dnmun]

i have a small handheld vacuum tool used for testing the diaphragms on the car. it has a small hose about 1/8" but you could splice on something more and connect it to a hypodermic syringe, arrange everything so you could evacuate the gas from the pouch using the hypodermic needle so that there was no gas left, and as it was removed from the hole then have a bead of nail polish surrounding the needle so the negative pressure inside the pouch would pull the acetone and nail polish varnish into the hole as the needle comes out. then put a piece of saran wrap on the top of the nail polish to form a barrier to air permeating through the hole. if it is the end cell you should be able to do it without too much hassle.

it would be interesting to see if that makes a difference.

 

[dogman dan]

Nail polish is basicly a laquer. Fast drying and pretty sticky, so it may be the best glue.

I wasn't sure what would work best, I haven't tried any repairs to puffies my self. What was Aussie Jester using? Was he using nail polish too?

Part of why I was saying it should be done as a temporary solution while waiting for new cells to arrive. I don't see it as a permanent fix.

 

[dnmun]

AJ used hot glue and cut it along the edge with a knife. but we never heard more about how long it lasted after that. that was lipo too i think.

 

[redstone02]

Sorry for the late follow-up... had too many irons in the fire.

The "puffer" was deflated. Near the top center of the cell I cleaned a small area with acetone and used a utility knife to pierce the cell skin. A piece of plywood was used to apply uniform pressure.
The HVAC industry uses an aluminum adhesive tape for sheet metal duct. I used two layers of one centimeter square pieces of this tape to patch the hole.

Hope time is kind to the repair….

Thanks for all the help.

Regards,
Tom

 

[999zip999]

Buy a new cell or new used cell as this may fail sooner or later. Or maybe Victpower will send you one.

 

[Ypedal]

pictures pictures pictures...

 

[neptronix]

Seems like these are worse than hobbyking lipo.
Yeah your house won't burn down, but there is an appreciable dud rate and the company sending them out isn't testing them as they should.

My recommendation: buy extras.
Also...
Buy now, because they aren't exactly selling the cream of the crop cells right now, but the last buyers will get what was scraped off the factory floor

 

[dnmun]

i did not realize you had done discharge tests before it had puffed up. i suspect this puffer is one that got overdischarged during your high load testing.

you did not monitor individual cell voltages during those tests i am guessing. no cell logs?

 

[redstone02]

i did not realize you had done discharge tests before it had puffed up. i suspect this puffer is one that got overdischarged during your high load testing.

you did not monitor individual cell voltages during those tests i am guessing. no cell logs?

Hello Dnmun,

Thank you for the critical thinking, it is good to get the needed input and different prospective.
I did use CellLogs with monitoring. During discharge the amp did not exceed 24.6 amperes and was ramped up/down. You can see the "peak" and ramp.

Referring to my notes:
"Mostly @ 16 ampere.
1 hour 15 minutes
Peak Ampere 18.71
Watt/Hours 941.7
Ampere Peak 24.6
Watt Peak 1300.6"

Cells voltage after BMS cut-off:
1:2.99
2:2.94
3:3.0
4:2.62
5:3.0
6:2.88
7:2.99
8:3.05
9:3.0
10:3.01
11:2.99
12:2.84
13:2.94
14:3.97
15:3.03
16:2.9

The cell voltage was measured ??; I did not know about "bounce-back" during this test. Voltages were measured shortly after the above and were higher.

When the load test was performed, the CellLogs had just arrived... I was still on the learning curve... cells 1 to 8 were over-written.

Thank you again for your input.

Best Regards,
Tom

 

[redstone02]

correction
Amp/Hour = 18.71 >>NOT Amp Peak<<

 

[neptronix]

Wow.
Talk about one cell being an underperformer. Was this a test you ran when you first got the pack?
I've never seen anything that bad in the RC world.

They must not be testing those at all. a simple IR test of that cell before assembly would have shown it to be a dud.

 

[redstone02]

Getting past my bed-time.
The CellLog image is for cells 9-19.
Sorry for not clarifing with first post.

 

[redstone02]

Wow.
Talk about one cell being an underperformer. Was this a test you ran when you first got the pack?
I've never seen anything that bad in the RC world.

They must not be testing those at all. a simple IR test of that cell before assembly would have shown it to be a dud.

Yes it is a real POS.
This was maybe the first discharge test.
Two others have been performed.
A real POS.
But the price was right... only cost a new BMS from BMS Battery.
A real POS.
Just got the batteries fitted to the bike with the new BMS. Will post some pics soon.
Yes the Victpower pack is a real POS.
POS.
Broke this MF down; fixed the bad connection, dicked around with Victpower re: the BMS, had to order a new one = ~30 day wait. Finally getting it together. Just taped it up tonight.
The Victpower pack is a real POS.
Not a happy customer. Just about burnt my feelings on A123. Our sources suck for the most part.

Sorry... got carried away... I agree with you... no testing... no give a shit what we ship... just hurry, get the money and ship turds with lip-stick.

...got carried away again...

Tom

 

[redstone02]

just confirmed = first test and first discharge of the pack. No other discharge, the image is #1.

 

[neptronix]

Haha well...
Given that the other cells are in good shape, it's not too bad.

When i order RC Lipos, i expect 10% of the packs i get in the mail to have dud cells in them.
Seems to be a consistent rate. Out of 28 packs i have had 3 packs with bad cells.

BMSBattery pulls the same stuff, i am sure.

 

[darkone040]

so i hear you are looking for pics of the biggest puffer...


another thing i have noticed is one cells has a discoloration on the cell.. it looks like whatever is on the inside of these cells is trying to eat its way out and the only thing stopping it is the outer plastic layer..


its only on the edge to i guess the cell wasnt sealed properly..

i also have a few cells when charged to 3.6volts after 24hours they are back down to 3.3volts.. the rest seem to stay around 3.5..

out of 28cells i think i have about 20 alright ones.. bit dissapointing..
im going to try and get warranty replacement on the stuffed ones..