I suspect these are Frey cells? (Aka Fortune, Overkill solar, etc). This is an interesting point. I wonder what role volume to
Indeed.
The EVE 280's have a much higher ratio of volume to surface area and lower C-rate. This may or may not be part of why EVE recommends compression. I would be curious to know whether other similar form factor aluminum cells (like CATL 202Ah, or ETC 277Ah) recommend compressions or 'fixture' and if their datasheets are any more clear on the method and the logic.
They definitely have a much higher energy density, so it makes sense that maybe they are pushing the mechanical envelope harder. Maybe there is less room to expand in there.
I may or may not be way off, but I have the impression that the bulge is the result of high state of charge more than c-rate. Can anyone confirm or correct my understanding on this point?
I don’t know the answer to your question, but I would argue we should not take them to ultra-high SOC either.
But, what I really meant was, I don’t know if expansion per se is a huge issue in terms of lifecycle, even if it turns out to have a small deleterious effect. I think most people are going to get so much life out of these that a little bit shaved off might not be worth optimizing for.
Then again, expansion might be a big deal if it causes the terminals to undergo mechanical stress vis a vis the bus bars. I would not want those to be moving around.