Energy Density: Seeking the best energy/volume ratio (Chart)

I put together this table for my own interest/research, I figured it might be of interest to others as well. I am interested in comparing volumetric energy density (Watt-hours / Liter), and finding the most energy dense cells. I have also included Watt-hours / kilogram, because, why not. If you would like to contribute see comment #3


*H2 = height of cell including terminal and/or stud, all calculations except Frey and CATL are based on H not H2
**CATL and FREY aren't an apples-apples comparison with the other cells. They measure weight and height differently in a way that makes them appear less energy dense than their competitors (they only list H2 (height including terminals) and measure weight as "less than or equal to x" whereas other manufacturers list "x plus or minus y"

If you would like to contribute / suggest a cell to be included in the comparison, here is the minimum that is needed:

1. Link to the manufacturer datasheet or cell specifications
2. Weight to two decimal places
3. L x W x H (height excluding the cell terminal)

Also if anyone knows what the actual cell height of the CATL 302Ah cells excluding the cell terminals, or has a link to a datasheet other than the one in the resource section of the forum, that would be helpful, thanks!

Thanks for putting this together.

how do the 500 amp/hour sinopoly's and calbs stack up in this comparison?

ken morgan said:

how do the 500 amp/hour sinopoly's and calbs stack up in this comparison?

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Not great in terms of Wh/Liter from what I recall (haven't looked at the 400/500Ah sizes in particular, but the trend should be the same I think)
There are good reasons to buy the nylon cased cells (very solid and mechanically robust cells), but I don't think energy density is one of them.

I will have a look at one or two of the common sizes of nylon cells and add to the comparison when I get a chance.

Okay I quickly threw together some numbers for a few different nylon cased cells, there may be some errors. All weight and measurement info comes from EVlithium.com.

Definitely nowhere near as dense in terms of Wh/L a bit closer in terms of Wh/Kg (especially when compared to stronger aluminum cased cells like Frey) but still not as dense. An interesting thing with the Nylon cased cells is that the ~200Ah size appear to be the most energy dense size when compared with both larger and smaller sized nylon prismatic cells.

I ask this as it seems see vey few issues with the nylon case cells and bloating/various issues... not saying it is due to case design, though it could be... I think its more towards the size vs energy density that causes the issue. with everyone jumping on bigger is better with aluminum cases, I thin they are seeing the problems that come from space vs energy density.

ken morgan said:

I ask this as it seems see vey few issues with the nylon case cells and bloating/various issues... not saying it is due to case design, though it could be... I think its more towards the size vs energy density that causes the issue. with everyone jumping on bigger is better with aluminum cases, I thin they are seeing the problems that come from space vs energy density.

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This is something I've thought about as well.
I think it comes down to at least two things.

(1) Physical Robustness/Build Quality: The nylon cased cells tend to be built much more robustly, its obvious just lookng at them, but you can really see it in the cross-section/teardown photos and videos, everything from the casing to the terminals. I saw an interesting study recently of Sinopoly and CALB 180-200Ah cells that mentioned that between 1/4 and 1/3 of the weight of these cells was case material. From a energy/weight standpoint you'd want that figure as low as possible, but in terms of physical robustness I suspect there is a positive correlation between this and physical strength. TL;DR all other things equal, a cell that devotes more weight and more space to casing and terminals will tend to be stronger but less energy dense.
(2) Size: The most common sizes of nylon cased cells are relatively small ~40-60Ah, ~100Ah, and ~200Ah. The geometry and the ratio of inner volume to exterior structure/surface area might be conducive to greater physical strength. This of course would apply to smaller more robust aluminum cased cells as well, Frey cells for instance apparently need no external compression, but like the nylon cased cells they have lower energy/weight and energy/volume ratios (though not as low as the nylon cased cells). One of the marine electrical resource that I trust most, recommends sticking to <200AH plastic cased cells for marine environments where high shock, high vibration, and humid or damp and salty conditions are common. TL;DR its not just the cell build, its also the size and form factor, a 300AH aluminum cased cell may be pushing up against the limits of what is possible with a thin lightweight cell without external fixture/compression (this is just speculation on my part).

Possibly (probably) there are more factors as well, things that go over my head, things specific to the manufacturing process, etc. And to some extent I think it comes down to design goals. A cell built for max energy density will make tradeoffs to optimize in one direction, a cell designed with strength as a priority will make tradeoffs to optimize in another direction. A cell like Frey/Fortune sorta splits the difference between the two.

This enclosed catalog includes size charter for nearly most brand cells.

Dzl said:

If you would like to contribute / suggest a cell to be included in the comparison, here is the minimum that is needed:

1. Link to the manufacturer datasheet or cell specifications
2. Weight to two decimal places
3. L x W x H (height excluding the cell terminal)

Also if anyone knows what the actual cell height of the CATL 302Ah cells excluding the cell terminals, or has a link to a datasheet other than the one in the resource section of the forum, that would be helpful, thanks!

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Would you be willing to add a few LTO cells for comparison? I feel like those are rising in popularity, and I would definitely like to know how they compare.

Figures don't lie , but liers can figure! with or without a Lab coat.

A.Justice said:

Would you be willing to add a few LTO cells for comparison? I feel like those are rising in popularity, and I would definitely like to know how they compare.

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I would be interested in that also, I'll look into it and see if I can find datasheets for a couple of the prismatic LTO cells.

Dzl said:

I would be interested in that also, I'll look into it and see if I can find datasheets for a couple of the prismatic LTO cells.

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Yinlong 40ah LTO