Weldability study of round aluminium magnet wires for lightweight low-cost traction electric motor applications

This paper explores the weldability of 1xxx and 6xxx series aluminium (Al) round wire welded to a range of Al and copper (Cu) plates to represent busbar and terminals for remote laser welding (RLW) and ultrasonic welding (USW), respectively. The motivations for materials are discussed and evaluated from a performance and high-volume manufacturing perspective for low-cost traction motors. The welding processes are assessed for their suited winding schemes. This paper proposes a novel approach of using USW to weld multiple thicker conductors with the aim of producing stranded wire terminations, similar to that commonly used for wire harnesses. The paper also proposes an alternative weld configuration as the main contribution for RLW. This utilises an axially focused laser beam direct to the interface between the wire and busbar. The aim is that this will improve the weldability of the Al-to-Cu specimens without the use of filler wire, commonly adopted in these scenarios, in addition to simplifying manufacturability. Lastly, the paper reviews the results of the proposed methods and discusses the manufacturing implications.