Here's some Tesla battery "secret sauce" for your enjoyment: (Don't even bother asking me how I was able to take these!)
Here you can see the bare 18650 laptop cells. They are interwoven with an aluminum channel (golden color) that carries coolant to each cell. Looks to me like a good 25% of each cell is in contact with this. (via way of a thermal pad and kapton electrical insulator)
Very large buss bar interconnecting the modules made of thin laminated strips of copper, that way it's still flexible.
This is the top of a module, each cell is connected to it's buss via a tiny single wire, which helps distribute current and acts like a fuse in the event of a cell fault.
Close up of the cell connection detail.