2 of my 8 cells damaged?

[GGameBoy]

I bought 8 310 amp catl cells on Ali express and after inspecting them a 2nd time and adding the bus bars I noticed 2 of them r bulging to the point they can rock back and forth with another cell. To my limited experience they seem to be brand new grade a like the listing said visually wise. They have original barcodes and have no significant marks. I am going to attempt a capacity test shortly.

the other 6, 5 for sure are completely flat and how I expected them. They all came in EXACTLY at 3.292 volts a month ago. Could these be used? Or damaged in shipping? Is bulging a common thing with cells? What’s ur thoughts? Do u need pics?

 

[Gazoo]

I bought 8 310 amp catl cells on Ali express and after inspecting them a 2nd time and adding the bus bars I noticed 2 of them r bulging to the point they can rock back and forth with another cell. To my limited experience they seem to be brand new grade a like the listing said visually wise. They have original barcodes and have no significant marks. I am going to attempt a capacity test shortly.

the other 6, 5 for sure are completely flat and how I expected them. They all came in EXACTLY at 3.292 volts a month ago. Could these be used? Or damaged in shipping? Is bulging a common thing with cells? What’s ur thoughts? Do u need pics?

You may refer to this thread. There are other threads of people reporting bulging with these cells if you search for them. But there is a big difference between bulging cells and cells that are slightly expanded.

Since the busbars reach then they are probably ok. Photos would help as well as a link to the seller.

 

[GGameBoy]

These were all taken at the same time. As u can see the cells r still charging. They r approx 3.37 volts per cell. Is this bulging normal?

 

[GGameBoy]

You may refer to this thread. There are other threads of people reporting bulging with these cells if you search for them. But there is a big difference between bulging cells and cells that are slightly expanded.

Since the busbars reach then they are probably ok. Photos would help as well as a link to the seller.

This is the listing. Surprisingly it now says 320 amp hours not 310. The seller is morecell battery store. also I added photos to the batteries themselves.

 

[Gazoo]

You are asking for trouble charging in series with no BMS. Cells need to be parallel top balanced with compression applied to prevent further expansion. Charging in series with a BMS connected and then parallel top balancing is ok and speeds up the process. It's also important to set the voltage of the PS before connecting it to the cells.

Your power supply should be in constant current mode. I suspect the alligator clips and maybe the cables are limiting the current because your PS is not putting out close to the 10 amps it's capable of and it's not in CC mode.

The bulging is more than I would like and is not normal expansion.

 

[GGameBoy]

You are asking for trouble charging in series with no BMS. Cells need to be parallel top balanced with compression applied to prevent further expansion. Charging in series with a BMS connected and then parallel top balancing is ok and speeds up the process. It's also important to set the voltage of the PS before connecting it to the cells.

Your power supply should be in constant current mode. I suspect the alligator clips and maybe the cables are limiting the current because your PS is not putting out close to the 10 amps it's capable of and it's not in CC mode.

The bulging is more than I would like and is not normal expansion.

Ok I will apply compression when charging. I have been watching the individual cells closely while charging. I have limited time with these cells before the wife gets back lol. I have been charging in series during the evening/night and then set them in parallel (no charging) during the day while at work in order to attempt to speed up the process.
Ya I think the cables the power supply came with r limiting my current. The cables r not hot maybe slightly warm to the touch. I did get it to 10 amps last night though. I must have been closer to the voltage then I thought? Maybe as a whole for all the cells?