Aluminium is the most cost-effective conductor of electricity available. It can carry electrical current for less than 15% the cost of carrying the same current, using copper. However, aluminium has lower conductivity than copper and the aluminium conductors need to be 1.6 times larger than what would be needed by copper in order to maintain the same performance and efficiency. For this reason, copper is the preferred material for most electric motors and almost all EV motors. However, when copper is replaced by aluminium in a hairpin motor it is found that the AC losses in the aluminium are much less than the AC losses in the copper, when all the AC losses are properly accounted for. In a hairpin motor the AC losses typically exceed the DC losses and the result is that the use of aluminium without any increase in conductor size in a hairpin motor results in very little loss of efficiency.
A recent development called Variable Conductor Area Technology (V-Cat) allows copper to be replaced by Aluminium in EV motors without any loss of efficiency saving considerable cost. V-Cat is a form of hairpin winding in which the end-windings and slot conductors are formed in aluminium using conventional die casting. The end-windings forming part of this conductor are much larger in cross section than the slot conductors. The slot conductors remain the same size as the copper they replace. This allows the overall combined DC and AC conductivity of the windings to equal or lower the original copper losses and so do not negatively affect the performance of the motor or its efficiency.
A typical hairpin motor using copper hairpins consumes around 8kg. of copper costing over $80.00 and this can be replaced by 2.5kg of aluminium costing $7.00. The manufacture of aluminum has significantly less environmental impact than the manufacture of copper. The loss of range for a motor similar to the VW ID3 base range of 346kms is less than 1,5km. Using the V-Cat design the range can be increased by a similar amount.