A Study on Laser Welding for Dissimilar Metals of Aluminum and Copper Using Pulsed Fiber Laser

Joining dissimilar metals poses critical challenges due to differences in their properties, leading to the formation of brittle intermetallic compounds (IMCs). Aluminum (Al) and copper (Cu) are widely used in electrical applications for their advantageous characteristics. In lithium-ion batteries, joints of these metals aim to harness their physical and electrical beneficial features. However, aluminum and copper’s high reflectivity and heat sensitivity present significant challenges in the joining processes. In the present study, a pulsed fiber laser, tailored for heat-sensitive components, was employed to weld Al/Cu and Cu/Al overlap configurations separately. Varied laser power ranges were applied to each welding configuration. The quality of the welds was assessed based on microstructure and mechanical properties. The results revealed the growth of dendritic IMCs towards the Al side in both welding configurations. Notably, the Al/Cu weld exhibited superior connection strength and fewer imperfections compared to the Cu/Al weld.