Ultra-high speed friction stir lap welding for automotive battery assemblies

Assembly of aluminum components for high-volume automotive applications requires fast, accurate and repeatable joining technologies. While spot technologies are often the joining method of choice for aluminum assembly, when a hermetic seal is required linear joining methods become preferrable. An investigation was made for joining AA6061-T4 sheet to itself, to die castings, and to extruded product as a means of demonstrating high-volume production of hermetically sealed assemblies. Targeted welding speeds were set for 10m/min using linear friction stir lap welding, which is well beyond documented production velocities to date. The efforts documented herein describe how scaling the process from 4m/min to 10m/min was effectively achieved across various product forms (sheet, castings, extrusions). The results of mechanical characterization including pressure testing for hermetic seal was documented for presentation.