A comprehensive Study on the Optimization of Laser Welding Process Parameters for Electric Vehicle Battery Interconnections

This study explored the application of laser welding for joining aluminum and Hilumin® for a cell-to-tab joints in Li-ion battery packs examining influence of laser-related parameters such as laser speed, laser power, and amplitude on the properties of welds and optimized the parameters by using Taguchi method. Initially aluminum and Hilumin® sheet materials were joined with laser welding. Electrical resistances of the welded samples were measured. Then, lap shear strengths were determined using the universal tensile device. As a result of the optimizations, it was determined which laser welding parameters would result in the minimal electrical resistance and maximal joint strength. In this study, the preferred minimized electrical resistance and maximized joint strength values for battery interconnection joints, with varying laser power, laser speed, and amplitude parameters, were achieved with a combination of 890 W power, 1 mm amplitude, and 8.5 m/min speed. If optimum parameters are used in establishing the connection, the maximum weld seam strength achieved was 32.36 MPa, and the minimum electrical contact resistance was 0.4186 mΩ. Findings show that laser speed has a significant impact on the formation of the weld, the material structure, strength properties, and the resistance at the electrical contact points. Increasing the laser speed also increased the strength of connection.