Dissimilar laser welding of copper and stainless-steel thin sheets for e-mobility applications

The article deals with laser welding of dissimilar materials: lap-welding was carried out in case of 0.24 mm thick pure copper on 0.5 mm thick AISI 304L stainless-steel sheets. The experiment was planned by means of DOE techniques and a full factorial design with three replicates was carried out. In order to characterize the joints, both in terms of mechanical and electrical characteristics, several analyses were performed. Shear tensile tests put in evidence the mechanical behavior of the joint with respect to laser power and welding speed, while hardness measurements allowed to evaluate the presence of eventual fragile intermetallic phases. Considering the potential application of this kind of joint in e-mobility, electrical resistance was measured by means of a 4-points micro-ohmmeter. Mechanical and electrical tests were performed both in single and in double bead configurations, so that the role of the extension of the joining area could be assessed.