Did I get new Grade A cells?

[Nomadicshow]

Hi all, i'm new here. I ordered 8 prismatic cells from tewaycell on aliexpress and i'm not sure if they're ok. i ordered 8 x 310ah cells and they're swollen, i'm not sure how much swelling is acceptable for new grade A cells, but they seem like B grade maybe because there is some swelling.

Can anyone tell me from the pics? I measured a single cell at 72mm, the 8 are 597 so divided by 8 is 74.625, an average swell gap of approx 2.625mm, actually a bit more because i only divided for 7 gaps. Is a 1.4mm of swelling on each side of a cell ok? Is it normal for grade A new cells? Or did i get ripped off? I haven't done a capacity test etc.

Also are these safe to use? I'll need to compress them but because there is already swelling i'm concerned about squashing them.

I included the qr code but don't know how to decipher the code for a manufacturing date.

Can of wd40 included for scale, those two are front and back shots.

 

[Nomadicshow]

Some gaps are bigger than others, i'll remeasure the sides.

 

[crossy]

I included the qr code but don't know how to decipher the code for a manufacturing date.

There's a thread somewhere with a decoder.

EDIT Found it https://www.gobelpower.com/lifepo4_decoder.html

 

[Nomadicshow]

So, it appears they were produced in 2019, which tells me they're not new at all. But hoping to hear some advice on the swelling too.

 

[houseofancients]

So, it appears they were produced in 2019, which tells me they're not new at all. But hoping to hear some advice on the swelling too.

they could be never used and just sat on a shelf.
the bigger cells are prone to some minor swelling.
only thing you can do is test their capacity and IR

 

[Nomadicshow]

My question is, do grade a cells have swelling and is this minor? I don't have a lot of experience with these cells

 

[joanna_lannie]

My question is, do grade a cells have swelling and is this minor? I don't have a lot of experience with these cells

The battery swelling problem does not occur with normal Grade A batteries, but slight swelling can be solved by compressing the battery, and this will not affect the performance of the battery. All you need to do is measure the internal resistance, voltage, and capacity of each battery first, if everything is up to standard, no problem. In addition, if you buy a large-capacity CATL battery, there is another reason in case of a swell: CATL has a factory located at a high altitude, which is relatively easier to swell.

 

[Bvillebob]

I bought 64 cells from Docan this year, 304 and 280 ah. They were all perfectly flat, not the slightest bit of swelling. Any cell with swelling isn't "Grade A", whatever that means. It does mean it's a lower quality cell. It will probably work for you, but it's not a premium cell.

The first battery I built with 4 280 ah cells from Aliexpress were like yours. I put them in my camper and they've worked fine for a couple of years. On the other hand they tend to wander in voltage, often showing 50-100 millivolt differences between cells. The 64 cells from Docan are typically within 5 millivolts of each other.

 

[Nomadicshow]

I measured the capacity today, 301ah, most of the cells would have made it to 310ah but one cell was low and got to 2.5v earlier. I'm kind of annoyed that the cells are a tad bloated and produced in 2019, but I knew aliexpress was a gamble. Not sure what to do, seems easier to let it go and enjoy the new capacity in the campervan. Maybe i can get aliexpress to give me a partial refund for the lower quality and capacity.

 

[Nomadicshow]

I really appreciate the comments, building solar diy can raise a lot of tricky questions, so many unknowns, it helps to have some feedback.

 

[squowse]

I measured the capacity today, 301ah, most of the cells would have made it to 310ah but one cell was low and got to 2.5v earlier. I'm kind of annoyed that the cells are a tad bloated and produced in 2019, but I knew aliexpress was a gamble. Not sure what to do, seems easier to let it go and enjoy the new capacity in the campervan. Maybe i can get aliexpress to give me a partial refund for the lower quality and capacity.

have you top balanced them? You might get the missing 9Ah

 

[Nomadicshow]

have you top balanced them? You might get the missing 9Ah

Yeah i top balanced