True packing efficiency is worse but compare it to the fact that each 54980 cell is ~ 9 times bigger than 2170 cell. Consider 9 2170 cells packed in a 3x3 square and you will see that the surface that they occupy is 37% more than 1 single 54980 cell including packing. Thus a 240 miles SR+ could give 330 miles if the pack is simply replaced with 54980 cells without increasing pack size. But I am sure there is more to it because a larger cell allows simpler pack electronics and construction and therefore makes cell to pack feasible. A larger cell may also be more energy dense than the smaller cell due to increase in active area and materials.
Basically without improving chemistry, Tesla dramatically improved pack level energy density by simply changing the cell and pack construction. This pack is not only energy dense but also allows faster charging. There always been a fundamental tradeoff between faster charging and energy density. Bigger cells allow longer range but not faster charging due to internal resistance but Tesla seems to have broken this limit or at least pushed this limit far out enough to not matter anymore for practical purposes.
So... using a rough example pack dimension of 4'x8' (~1248x2496mm):
21mm diameter cells-
Triangular Pattern
Maximum number of circles with the triangular pattern inside the
1248 x 2496 rectangle is:
8015
As a 21mm cell has an area of 10.5^2 x 3.14 =
346.2mm^2, that means 8015 cells cover
2,774,673 mm^2
For a (assumed) 54mm diameter cell-
Triangular Pattern
Maximum number of circles with the triangular pattern inside the
1248 x 2496 rectangle is:
1193
As a 54mm cell has an area of 27^2 x 3.14 =
2289mm^2, that means 1193 cells cover
2,730,849mm^2
So.. indeed the packing density is worse, but only very slightly at about 1.6%. However that ignores the lesser percentage of each of the larger cell's volume that will be apportioned to casing material, as opposed to actual anode/electrode volume. I'd suspect that might make up for the slightly less efficient packing... and maybe even give the larger cells an edge...
This of course ignores cell height, which isn't really a factor for packing in a single stack, and would need to be the same dimension to compare apples-to-apples for total cell count. It also ignores any volumetric improvement in the vertical dimension that may be attributable to the tabless design and/or integrated cap & current collector...
I still have too many people in my life saying $35k is too expensive for them....these are small families my age (mid 30s) that have at least two kids.
