And twice the resistance doesn’t matter. So you go one gauge bigger. If the material is cheaper, more available, and suitable, that’s fine. We don’t insist on gold wires because they’re “better” than copper.
It’s all tradeoffs. I don’t see a reason to be philosophically opposed to aluminum other than “it’s possible to do it wrong”, which is of course also true for copper.
Indeed, but automotive wiring is subject to intense and persistent vibration and heat cycles. so all those ties become stress points for fatigue to cluster around.
I'm not saying its never a good idea to use an aluminium wire loom, but I'm struggling to find a situation where its required
The place Tesla used this was for fixed rigid bus bars, notably the "cable" from the charge port to the battery.[0]
Previously they used traditional stranded copper. Now it's a solid aluminum conductor, wrapped in insulation and protected by an outer aluminum tube.
These are thick high voltage conductors. I'm sure Tesla did their homework on flex and fatigue.
As for resistance, this is why I mentioned conductivity-to-weight as being the critical metric. Copper is over 3x as dense, at 9.0 g/cm³ vs 2.7 g/cm³ for aluminum. It doesn't hurt that aluminum is cheaper and more abundant.