A Comparison of Multi-Layered Ultrasonic Joints Fabrication using Layer-Wise vs Stacked Approaches for Battery Interconnects

This paper investigates two different approaches, namely the ‘Layer-wise Approach’ and ‘Stacked Approach’, employed to create multi-layered joints using ultrasonic metal welding (USMW), especially useful for electric vehicle (EV) battery interconnects. One such requirement is for the pouch cell to create multiple tabs to busbar joints. Multi-layer dissimilar joints were made using copper (Cu) tabs and aluminum (Al) busbars of thickness 0.25 mm and 1 mm, respectively. The 5Cu tabs to 1Al busbar joint created by layer-wise techniques exhibited 3.78 and 2.47 times more mechanical strength (∼237 N) than 3Cu to 1Al busbar and 2Cu to 1Al busbar combinations (as more than 3 Cu tabs to busbar welding was not possible using stacked approach), respectively, while necessitating reduced heat generation and clamping pressure.