| Abstract Scope |
Joining multiple thin foils of current collectors to a conductive tab is one of the critical processes to ensure battery life. In this study, multiple thin pure aluminum foils with layer number 25 to 100 are joined to tab by a recently developed ultrasonically assisted resistance spot welding (URW) hybrid process. In the weld schedule, the ultrasonic vibration was triggered by preheating current, continued during the main weld current, and stopped when current is off. Under the same electrical pulse parameters, URW welds show improved mechanical properties and microstructure than conventional resistance spot welds (RSW) . Lap shear tensile tests and microhardness mapping showed higher strength of URW welds. In addition, the maximum force before the lap shear tensile failure increases linearly proportional to the number of foil layers in URW condition. Moreover, enlarged nugget size, as well as reduced porosity, were observed at the URW weld cross section. |