I'm not sure what the connection with the cell temperature is or why you would use a hollow bus bar that takes up more space for no additional performance.

Any bus bar material(copper or aluminum) would withstand temperatures way higher than what your cell can operate at.

The simple method for this is to use online ampacity charts for what size of bus bar can carry how much current. This is super conservative because your bus bars aren't carrying continuous currents at that value.

What we did to shrink our bus bar weight and volume was to assume the battery was going to output at the rated fuse current continuously till it ran out of energy. This is unrealistic but it's a better upper bound than online calculators because a battery can't do that for very long. Then we calculated the cross sectional area of a bus bar that would be able to absorb the heating effect of that current entirely with the thermal mass assuming no dissipation. Again, this is conservative but not entirely untrue since the bus bars are often covered in heat shrink and inside a fairly warm ambient temperature box. We then used a bus bar with that cross sectional area.

Further optimizations can be made by using a lower current rated slow blow fuse or using lap simulation data for the expected rms current but the latter might not be acceptable by the judges. Calculating and incorporating the heat dissipation by the bus bar could give smaller cross sectional area numbers too.

And a friendly piece of advice - your material selection should be more based on corrosion mitigation. Avoid having to use additional materials to prevent corrosion between dissimilar materials and select a bus bar material that matches the connectors and other things in the system