Higee 280AH cells made in April 2023 - compression/fixturing or not?

[Luk88]

I've seen a bunch of videos online and read all I could find about cell compression/fixturing and I'm leaning towards doing it.

However, I recently saw a datasheet (from this forum) for my cells from Higee Zuhai(b) plant and there is no mention of fixturing and complression at all in it. Cells are rated for 6k cycles. I never held any other cell in my hand so I can't compare if they use heavier gauge aluminium or what, but is it possible I don't have to worry about compression and still not have my cells bulge slightly when charged?

Do any of you use Higee cells? Did they swell when charged without compression?

 

[sunshine_eggo]

All cells expand slightly when full vs. empty. If a cell "swells" significantly during proper charging, it is bad

That datasheet does not specify the difference in charged and discharged dimensions. That's a concern.

Generally speaking, compression is regarded as beneficial. I personally look at it more as "constraint" to prevent excessive expansion during charging.

 

[Ampster]

I do not think swelling is related to the brand. I think it is the thin Aluminum cell skins and the chemical changes from charging and discharging that cause swelling. The risk of swelling is the strain on terminal connections and mild compression mitigates that.

 

[zorlig]

Yeah it is not the brand, but the chemistry.

Cell compression was always advised.

I have 24 cells compressed together and see zero expansion from empty to full.

I have my doubts about people who say the cells expand under compression - if they actually have any.

Uncompressed cells expand and contact. If I remember correctly it's because they make gas because they are uncompressed.

 

[Luk88]

Yeah it is not the brand, but the chemistry.

Cell compression was always advised.

I have 24 cells compressed together and see zero expansion from empty to full.

I have my doubts about people who say the cells expand under compression - if they actually have any.

Uncompressed cells expand and contact. If I remember correctly it's because they make gas because they are uncompressed.

Interesting. How did you choose the right amount of force? Do you use spring washers etc?

I decided to build a compression fixture (I posted a picture in another thread), but now I wonder about the risk of overtightening.