Influence of Process Parameters on Formation of Al/Cu Dissimilar Weld Using Ultrasonic Welding

The battery of an electronic vehicle consists of hundreds or thousands of battery cells. Since each battery cell is electrically connected to each other, the quality of the battery depends on the performance of welded joint. Ultrasonic welding is a solid-state process that is possible to apply to secondary batteries assemble due to its low electrical resistance and wide joint area in a short time. In the present study, a 0.3 mm thick aluminum for tab material and a 1.0 mm thick copper for busbar material were welded by ultrasonic welding. The aluminum was placed at the sonotrode side, and copper was positioned at the anvil side, respectively. The effect of process parameters such clamping pressure, amplitude of vibration and welding time on joint characteristics was investigated. As a result, it was observed that depth of indentation significantly increased with increasing welding time compared to clamping pressure. The normal-welded morphology was formed at welding time of 0.3 s and then the maximum tensile shear load was 0.93 kN, which is the highest.