I don't know very much about it, but i think that it could be used for its electrical conductivity property per weight versus copper.
To make a realistic comparison of the basic cost of copper versus aluminum for conducting electricity, the conductivity and density of the two materials must be considered. Electrical conductor (EC) grade aluminum is rated at 63% IACS (International Annealed Copper Standard). Combining this conductivity measure, which is on a volume basis, with the densities of the two metals yields the result that 0.22 kg of aluminum has the same conductive capability as 0.45 kg of copper. To complete the cost comparison it is, of course, necessary to make allowances for fabricating both materials into final form.
For the characteristics of wiring systems of cars, i don't think that a substantial amount of weight could be saved by using aluminum. Maybe it could be used in F1, don't know.
Now, in high power applications such as transmission lines, it is used for this property. With this in mind, it could be used in KERS power conductors to reduce weight, or in the motor/generator windings. Maybe scarbs could know something about this if it's indeed true. However, it need to be said that aluminum opens a lot of new problems in the motor design.
For more info:
http://www.keytometals.com/Article91.htm
Another link:
http://www.achrnews.com/Articles/Featur ... 32a8c0____
Hope it helps...
"We will have to wait and see".