Overlap joining of aluminium and copper using laser micro welding with spatial power modulation

The rising demand for high power battery systems for the electric mobility requires the connection of a large number of cells. Due to the functionality of the cell chemistry, a combination of copper and aluminium is necessary. The differing material properties like thermal conductivity as well as the formation of intermetallic phases are challenging for welding processes. This study contains the results for overlap joints of copper and aluminium using a laser beam welding process with spatial power modulation. With a parameter variation, the cross-sectional shape of the weld seams and therefore, the ratio of depth to width can be adjusted. With additional longitudinal cross sections and an energy-dispersive X-ray spectroscopy analysis, the different mixing behaviour of the dissimilar material depending on the top layer is investigated.