Aliexpress 190AH Lifepo4 Batteries bloating

RobertPP

New Member
Joined
Jan 8, 2021
Messages
1
Hello,

I've built a battery pack with the ever so famous 190AH Lifepo4 Batteries from Aliexpress:

After a bit of testing I noticed that one or two of the cells started bloating a couple of milimeters (can't say if they were in this stage when the arrived). The pack has been used with the 120A DYKB BMS and it has only a couple of test cycles. No cell is showing self discharge and nothing heated up during charge or discharge.

Measured pack capacity: round about 180Ah,
Max Cell charging voltage was: 3,6V
Stopped discharging as soon as one cell reached 3V.
Charging and discharging current was 3A.

Please let me know if you think that the bloating is already too dangerous (fire hazard). For safety reasons I am storing them right now at 3V.

This is the sellers response after he has seen the pictures:
<<Hello, it looks normal at present. Please make sure your bms is working properly and your charging method is correct.>>


Any advice is appreciated.

Thanks,
Robert
 

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floydo

New Member
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Dec 7, 2020
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Look around the forum....Courtesy of Steve...
 

snoobler

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Jul 10, 2020
Messages
8,430
Location
HBR, AZ
Swelling during charge is normal. Most prismatic specifications give different dimensions for fully charged vs. not fully charged. Most prismatics will last longer if constrained (clamped) firmly.
 

Just John

Photon Sorcerer
Joined
Aug 15, 2020
Messages
2,380
Hello,

I've built a battery pack with the ever so famous 190AH Lifepo4 Batteries from Aliexpress:

After a bit of testing I noticed that one or two of the cells started bloating a couple of milimeters (can't say if they were in this stage when the arrived). The pack has been used with the 120A DYKB BMS and it has only a couple of test cycles. No cell is showing self discharge and nothing heated up during charge or discharge.

Measured pack capacity: round about 180Ah,
Max Cell charging voltage was: 3,6V
Stopped discharging as soon as one cell reached 3V.
Charging and discharging current was 3A.

Please let me know if you think that the bloating is already too dangerous (fire hazard). For safety reasons I am storing them right now at 3V.

This is the sellers response after he has seen the pictures:
<<Hello, it looks normal at present. Please make sure your bms is working properly and your charging method is correct.>>


Any advice is appreciated.

Thanks,
Robert
I'll be honest, I don't see any bloating from your pictures. The cells do a little expansion and contraction from normal charging and discharge, but really not enough to notice much. It's part of the chemical reaction when storing a charge. If you are measuring a couple of millimeters, that is indeed normal, centimeters is not.
 

kuranaga

Solar Enthusiast
Joined
Sep 24, 2021
Messages
137
the question is how do you make a pack if the cells swell? Busbars will rip the terminals apart. Should we use instead bent AWG#2 wire bridges with lugs?
 

Ampster

Renewable Energy Hobbyist
Joined
May 3, 2020
Messages
4,365
Location
Sonoma, California
the question is how do you make a pack if the cells swell?
The solution is to clamp the cells so the swelling does not rip the terminals off. Years ago I had some Thunderskys swell because of over discharge, They were not clamped and they just fanned out. The cases on those were more robust and the bus connections were flexible to allow the bottoms to fan out. I only lost two out of 32 cells,
 

kuranaga

Solar Enthusiast
Joined
Sep 24, 2021
Messages
137
The solution is to clamp the cells so the swelling does not rip the terminals off. Years ago I had some Thunderskys swell because of over discharge, They were not clamped and they just fanned out. The cases on those were more robust and the bus connections were flexible to allow the bottoms to fan out. I only lost two out of 32 cells,
mine 280Ah from ETC did swell about 1mm after few cycles. And I'm thinking about replacing busbars with wire bridges that can bend, despite clamping the cells with 1/2" plywood.
 
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