Confine prismatic LifePo4 or not?

[Strobi-1]

This question is keeping me up at night! Do LFP prismatic cells need to be confined with compression plates or do you want to leave space between cells so they can expand and contract? I've search all over and have found compelling arguments in both directions. I purchased used Calb Cam72 cells and assembled with 10-32 allthread, Calb plastic cell caps and Calb center spacers/nameplate and used them for one weekend. Before connecting, I bottom balanced them. Then charged them very conservatively with 400w panels and epever charge controller (with settings I learned here) to about 80% and didn't discharge below 50%. all cells remained balanced. When the weekend was up, I noticed that the outside cells had a very slight bulge. Does anyone know the proper way to mount/assemble these cells? Any insight would be greatly appreciated.

 

[Maast]

The three killers of lfp cells are: 1 - charging in freezing conditions (instant permanent degradation/death), 2 - Overcharge/discharge, 3 - Heat (electrolyte solvent evaporates). Also, lfp's last longer the cooler they are, they have slightly less capacity but last a lot longer.

So given that I'd leave them plenty of air around them to cool and furthermore leave a air gap between each one to keep them cool.

 

[Strobi-1]

Thanks for the reply! So I guess the theory of keeping between compression plates is no long a thing?

 

[Maast]

Unless you're dealing with pouch cells I wouldnt, you still can if you want but put a spacer between them.

 

[April]

In marine use its been found side compression is a must have in plastic prismatics .Some of the aluminium sided prismatics are filled like torch cell batteries but with long oval type layup of the plates and they still heat up and swell. If you draw too much out or put too much in at too high a rate then heat causes swelling . You need compression of the whole battery and some spacers between each cell so air can flow up the sides .

I dont see why there use in a house or car would be any different so compression is still a must have I think.