How dangerous are swollen LiFePo4 cells received from AliExpress ?

[ereams65]

Easiest way to cut 1/8" stock copper or aluminum is by using bolt cutters. Gives you a halfway smooth edge too, once you round of the corners with a file. As for drilling, owning a drill press is the key. Use a decent bit, keep some oil and water on hand to cool it off and take your time. Easy peasy.

 

[rplarry]

As everyone knows copper is soft so drill it at high speed with a sharp drill bit and light pressure on the bit so it doesn't grab and spin your work.

 

[RustyR]

SCAM!!!! I bought 64 'Brand new 200AH' cells tested them and only got 117-133AH. Watever you do do not buy from this company. They only sell used and substandard cells. Don't fall for their cheap prices there is a reason for it. They insist the batteries are new and refuse to resolve the issue. They have no interest helping their customers. Please see my test results below.

 

[RCinFLA]

A general question on swollen cells.
I believe that inside the case are pouches of individual cells, all connected in parallel. Pouches like these;

https://www.geebattery.com/LiFePO4-battery/large-lifepo4-pouch-cell

At some point there was a buildup of gas pressure from one or more of these pouches which was so severe that it caused the outer casing to distort. These outer casings are made of aluminum which means they are not elastic and won't return to their original shape on their own.
So, can the pouch cells re-absorb the gas that caused the swelling, and return to their original shape, meaning that the aluminum casing can be squeezed back to it's original shape?

Pouch cells are constructed differently than metal can cells. Metal can cells have open ended wrap pouches (they are not sealed). On metal can cells, the metal can is the seal. When the metal can cells bloat it is just the outside metal can that swells, the pouch wrap does not.

The open top end of pouch laminate wrap may expel a slight amount of electrolyte into the metal container area during overcharge bloating. Gases are created within the wrap laminates but it quickly works its way through laminates and escapes the open end of cell wrap building pressure within sealed metal can container. The created gases working their way up the laminate to open top of pouch can carry some free electrolyte liquid with it, pushing electrolyte out the top of pouch.

It is common for a little electrolyte to get into metal can container area during electrolyte filling during manufacturing. You might hear a little sloshing around in bottom of metal outer casing.