So... having watched/read some of the battery day prognostication, something dawned upon me.
We know/surmise the following:
- There's going to be larger cell format (45-54mm diameter)
- The new cell will be tabless design
- Internal resistance should be reduced
- The volume-to-surface area for the contents vs. can would be increased
- The number of jelly roll layers increases
So when it comes to power vs thermal management, it's surmised that the lesser internal resistance of the new tabless design should produce less internal heating during high power charging or driving. This would help offset the lesser can surface area for cooling. However, the larger diameter cells imply that the heat has to travel through more insulative jelly roll layers to eventually be extracted from the cell.
But then I realized: the very thing that makes the tabless cell such a great performer in terms of power, would also make it a great performer for thermal management.
That is, the metallic foil that's a great power conductor is also a great heat conductor. And that tabless design that radically increases the area of contact for electron flow also increases the contact area for heat extraction. And there aren't multiple anode/cathode/sperator layers for the heat to travel through when traversing the foil to the edge where it contacts the cell cap.
And Tesla already has to make a mechanical connection to the cap to collect current. That current collector is metallic, which is also a great conductor of heat.
So here's my not-really-a-prediction for battery day: A single mechanical connection to the cell cap provides both electrical and thermal coupling.
This could even be some sort of common plate that integrates the cap/current-collector/cooling-medium that spans groups of cells. If highly integrated, this could reduce parts count and ease assembly.
There are some caveats certainly: Tesla uses fusible links for each cell, these are likely too small to be effective cooling conductors... so something would need to change there. Tesla also uses top-cap connections for both the positive and negative connections on the 2170's, that might make a common collector difficult.
So I don't give this a very big chance of actually happening... at least as part of today's announcements. But I could see it being a thing in the future.
(disclaimer, I didn't watch every single battery day video, so if this idea has already been covered, please ignore me)
