That is a sick pack.
NCA chemistry cells so they have a few thousands cycles in them and good cold weather performance and a more reasonable C-rate (like 5C bursts).
A thermal transport medium contacting each cell through a thermal pad to a flattened aluminum hydro-formed (I'm guessing) pipe wrapped in Kapton to prevent shorting potentials between cell group cases at different potentials. Flow the liquid in, it flows out either with less energy left in it if you're heating the pack on a cold day, or flow out with more energy in it to get transferred to the air through radiator if you're flogging the pack.
They fixed my biggest issue with tab welds on round cells, which is fatigue from minimal compliance distance and the inherent stress-focusing/riser action of two surfaces being bonded by little connection spots. Those long bond-wire looking interconnects are brilliant. Things can flex and vibrate and wiggle for a very long time, and it's wiggling over a long distance of material, so everything stays well inside it's non-fatiguing range of its stress curve.
I love that it functions in a way that any cell can have any type of cell failure and it's ultimately a non-event, the pack just reduces in capacity by a percent or something the user likely would never even notice.
That is the best method to do an 18650 pack that I've ever seen.
Kudo's to you Tesla, and Kudo's to you Elan Musk, you've made some awesome things happen in the world. Big respect.
-Luke