Compressing Prismatic Cells?

[Marnus101]

Hi Everyone
I purchased a bunch of cells from a reputable supplier. The supplier suggest I should compress cells from both sides (500-1000kg of force) to unsure a long cycle life. He mentioned that the cells are a "rolled" technology and that's why they should be compressed. Please see attached images of the technology mentioned. Is this true and what would the drawbacks be of not compressed?

 

[HRTKD]

Yes, the cells are "rolled". There was a video posted recently of a guy taking apart a cell that wasn't an EVE, but it was close. Strange looking battery on the inside.

 

[Steve_S]

WOW, 500Kg force ? That will make a pancake !
Good God, Inch Pounds not Foot Pounds ! Never crush the cells, basically, not more than a really good Hand Squeeze amount of pressure.
Compressing the cells prevents bloating & delamination internally (kiss explanation) and does extend the lifecycles accordingly. Almost all manufacturers recommend a certain amount of "binding", "compression" or "fixing", all of which means that the cells should be bound, slightly compressed to maintain their form factor and prevented from moving freely. Also this reduces any stresses on the terminals which are not as "tough" as most people think they are.

 

[Marnus101]

Thank you so much for detailed explanation!
I know right!!!Crazy amount of force. Anyway, do you suggest we compress from both sides or just the side with the larger area?

 

[Steve_S]

Funny Thing, I just did this post the other day.

Best way to compress cells in packs

Just looking for everyones best ideas to compress cells. I know Will used pipe clamps. Is that still the best method?

diysolarforum.com

 

[Luthj]

The Eve 280AH cells which are popular, shows 600lb compression spec, which is around 10-15 lb/in of surface area. That's well within the sane pressure zone, and poses no risk of cell damage.

 

[Marnus101]

@Steve_S could you please give me advice in my other thread? I hacked the ANT-BMS completely and can control every single function separately using a micro controller.

ANT BMS in parallel configuration

Hi Everyone I would like to know if anyone has successfully connected two 16S ANT BMS's ( 48V100Ah System) in parallel? Cells are from same batch in both batteries. We ask the seller and he said: " For Parallel, our bms do not support that. the parallel bms have hardware DCDC to avoid large...

diysolarforum.com

 

[Jeremiah]

@Steve_S could you please give me advice in my other thread? I hacked the ANT-BMS completely and can control every single function separately using a micro controller.

ANT BMS in parallel configuration

Hi Everyone I would like to know if anyone has successfully connected two 16S ANT BMS's ( 48V100Ah System) in parallel? Cells are from same batch in both batteries. We ask the seller and he said: " For Parallel, our bms do not support that. the parallel bms have hardware DCDC to avoid large...

diysolarforum.com

Can you share with me the results of your hackery?
PM is fine if you don't want to expose it here. I also fiddle around with microcontrollers so this can be very useful for me.
Thanks!
-Jeremiah

 

[Jeremiah]

Any chance I can convince you to share the results of your hacking of the ANT BMS?
Do you have a simple IDD you have slapped together (chicken scratch would be fine).
I'm living & working in the 3rd world and have very limited time for my own solar "hobby" so if you've hacked the ANT (I have 3 on hand), I'd really like to be able to talk to them with a pic (PM is fine if you're feeling generous but don't want to share your results with the world).