Al Alloys and Casting Processes for Induction Motor Applications in Battery-Powered Electric Vehicles: A Review

Abstract

With the rapid expansion of battery-powered electric vehicles (BEVs) in the automotive industry, research interest in lightweight Al alloys as well as their casting processes and applications has increased considerably. The substitution of castable aluminum alloys with superior strengths and electrical conductivity for copper reduces the weight and size of electric induction motors, and improves the energy efficiency and driving range of the BEVs. The present article was intended to give a general introduction into the common cast Al aluminum alloys and their relevant processes, as well as to motivate the development of high strength and conductive Al alloys for the practical realization of Al applications in the motors of the BEVs. A number of cast alloy systems containing Cu, Si, Ni, Mg, Fe, and Ti were evaluated, in comparison to nanostructured wrought Al alloys. The conventional casting processes suitable for Al alloys, high pressure die casting, squeeze casting, and sand casting were described. Strengthening mechanisms including solid solution strengthening, precipitation strengthening, dislocation accumulation strengthening, and grain boundary strengthening were presented. The phenomenon of electrical conduction for Al alloys was outlined. The mechanical properties and electrical properties of the recently developed Al alloys for casting and deformation processes were comprehensively listed and critically reviewed in association with microstructural characteristics.

Keywords

• Al alloys
• casting processes
• electrical conductivity
• electric motor
• electric vehicle
• mechanical properties