redstone02
100 W
- Joined
- Aug 1, 2012
- Messages
- 102
That is an impressive puffer!
What ya going to do about it?
Replace or burp?
What ya going to do about it?
Replace or burp?
Puffing A123
- Thread starter redstone02
- Start date
999zip999
100 TW
This seems like the round cell packs that Victpower makes just thrown togethere.
dnmun
1 PW
it appears that #4 in your list is the low cell. usually when they cut off at 2V they will rebound all the way back up to 2.7-2.9V so it was #4 that shut off the BMS.
is that the puffer?
is that the puffer?
parabellum
1 MW
What is about cell 14? 3.97v after LVC or typo?
redstone02 said:
redstone02
100 W
- Joined
- Aug 1, 2012
- Messages
- 102
parabellum said:
redstone02
100 W
- Joined
- Aug 1, 2012
- Messages
- 102
999zip999
100 TW
I'm thinking cell # 14 at 3.97v is a problem and will shuts down the bms early put a light bulb or something on it to bring it down ?
redstone02
100 W
- Joined
- Aug 1, 2012
- Messages
- 102
#16 is the puffer.dnmun said:
A cell that falls inline with an average for the pack.
Yeah, go figure. Had me scratching my head. I expected it to be high or low on the celllogs... it is the average joe.
1000w
1 kW
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..
I've had the same thing happen to a few of my cells. It's some sort of corrosion of the foil pouch, the cells often puff when they develop this issue.
I have no idea why this corrosion occurs. Once this happens you'll need replacement cells as the electrolyte will gas off and the voltage will fall.
Cheers
I've had the same thing happen to a few of my cells. It's some sort of corrosion of the foil pouch, the cells often puff when they develop this issue.
I have no idea why this corrosion occurs. Once this happens you'll need replacement cells as the electrolyte will gas off and the voltage will fall.
Cheers
dnmun
1 PW
maybe what happens is that the plastic lining on the inside of the mylar/plastic film has a void and the electrolyte is eating up the aluminum layer of the mylar. from the inside.
EVDragRacer
1 kW
- Joined
- Dec 10, 2010
- Messages
- 318
Just curious guys, Vicpower Chinese A123 cells have been proven to be rejects and puff/ leak on many applications, why are you still wasting your money? The DIY Forum did a complete Thread on damaged Vicpower cells, most will fail in time.
miro13car
100 kW
nobody wastes money on A123 20Ah pouches.
At least I do not.
I have been using them on my 1000W Eplus ebike with success and I am sure they /cells/ will last
Everybody has right to an opinion.
A123 simply sold substandard/rejected pouches to more than one so called liquidators like VictPower.
or
cells were diverted from recycling , frankly I don't care.
For sure:
there were rejected for mechanical and electrical reasons.
There are still plenty good for hobbist ebike market.
After comparing my charts from CBA with Mavizen CBA charts of exactely same cells, I do not see much difference.
Voltages on charts at 18Ah discharged for example are very, very close.
Electric car is all completely different application.
I draw max 30A on my ebike..
At least I do not.
I have been using them on my 1000W Eplus ebike with success and I am sure they /cells/ will last
Everybody has right to an opinion.
A123 simply sold substandard/rejected pouches to more than one so called liquidators like VictPower.
or
cells were diverted from recycling , frankly I don't care.
For sure:
there were rejected for mechanical and electrical reasons.
There are still plenty good for hobbist ebike market.
After comparing my charts from CBA with Mavizen CBA charts of exactely same cells, I do not see much difference.
Voltages on charts at 18Ah discharged for example are very, very close.
Electric car is all completely different application.
I draw max 30A on my ebike..
miro13car
100 kW
puffed cell was simply overcharged wich faulty BMS with no balancing.
Same thing happened to me when I overcharged pouch with primitive single cell charger before buying quality smart single cell 3.2V chrger for my tests.
My puffed A123 is sitting outside under my deck, looks identical to the one in the picture .
I do not believe any A123 would do it in normal voltage range.
Even after dead short on one of my A123 pouches it still passed 30A discharge test with EXACT SAME capacity.
It was my mistake.
Lesson was learn,
Same thing happened to me when I overcharged pouch with primitive single cell charger before buying quality smart single cell 3.2V chrger for my tests.
My puffed A123 is sitting outside under my deck, looks identical to the one in the picture .
I do not believe any A123 would do it in normal voltage range.
Even after dead short on one of my A123 pouches it still passed 30A discharge test with EXACT SAME capacity.
It was my mistake.
Lesson was learn,
puffed.. AND at 0v = remove and discard.
You might be able to force it into taking a charge and delivering something, maybe, but in the best possible situation it will be a weakling and self discharge fast... save yourself and the rest of the pack the trouble.. just get rid of it imo.
You might be able to force it into taking a charge and delivering something, maybe, but in the best possible situation it will be a weakling and self discharge fast... save yourself and the rest of the pack the trouble.. just get rid of it imo.
wb9k
10 kW
eTrike said:I just had one puff at near 0V... Sadly it was cell 28 (positive end) of a 28S3P module. The rest were at 2.7V. Any updates on how the cells performed after venting and resealing? Or any other tips would be appreciated.
I'm considering using just 24S of the packs for another reason, so I'm trying to see a silver lining in this otherwise dark cloud
How near zero? If it came to rest below 0.5 Volts or so, you MUST discard the cell. It can no longer safely accept and hold a charge.
I see this is an old thread...the failure mechanisms described here (puffing, overdischarge consequences, black spotting on the cell exterior) have been explained in detail in other threads since this one was started.
Absent severe overdischarge, burping and resealing a puffer MIGHT get more life from these cells in a light duty application, but that cell is now compromised and will likely continue to deteriorate at an accelerated rate. If your BMS (or other monitoring system) is not capable of shutting things down completely when they go too far awry, or of keeping the wounded cell within balance, things could get ugly rather abruptly down the road a bit. Extreme vigilance is required at this point. The fact that this happened in the first place is a sign that something was wrong with the battery system to begin with--most likely the cells were not compressed properly, but BMS failures could also be to blame.
wb9k
10 kW
Man, that's some old stuff. 7S3P? Look like early (recalled) Fisker modules. Factory compression bands look original as far as I can see in the photos. This is probably just a defective cell.
liveforphysics
100 TW
Pouch outer plastic has pinholes.
This let's the inner aluminum layer of the laminate to corrode away internally. Pouch foil edge corrosion is a critical element to design around prohibiting in any pouch cell pack designs you wish to last.
This let's the inner aluminum layer of the laminate to corrode away internally. Pouch foil edge corrosion is a critical element to design around prohibiting in any pouch cell pack designs you wish to last.
wb9k
10 kW
liveforphysics said:
Really? That's a new one on me. Are you saying that if air touches aluminum that the opposite side of the aluminum will corrode?
The mechanism I know that causes black spots to appear on the exterior of A123 cells is a pinhole in the INNER poly layer of the pouch that allows a conductive path <~5MegOhms to the cathode (edit: not the anode.). With the pouch held at cathode potential, Li in the electrolyte will alloy onto the aluminum, causing decrepitation of the pouch. It becomes brittle, cracks, and eventually leaks electrolyte. This doesn't cause puffing, however.
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