Laser welding is increasingly used in e-mobility applications, particularly for copper and aluminum components such as busbars and battery housings. However, their high thermal conductivity induces melt pool instabilities, leading to critical defects such as hot cracking and lack of penetration. This work presents experimental results obtained in several collaborative and European projects, focusing on beam shaping as a lever to improve process robustness.

For battery housing assemblies, multiple joint configurations involve both by-transparency welding and hybrid laser-arc welding (HLAW), leading to the evaluation of application-specific energy distributions:

In aluminum welding by transparency, a 4spot pattern based on ring-dot intensity distributions was compared to triangular, ring-only, and Gaussian beams. Defined to achieve a spot size of 1010 µm in the process plane, this configuration enabled the suppression of hot cracking on dissimilar Al 5xxx / Al 6xxx assemblies.

In HLAW configurations with filler wire, an Al 5xxx wire was tested to improve weldability. A parametric study on the parameters of the 4spot shape was investigated to reach a scalable process.

For copper busbar butt joints, ring-dot beam shapes were assessed to mitigate insufficient penetration and lack of penetration at weld initiation. Results show that a minimum of 3 kW in the core, combined with optimized power ratios, is required to achieve stable and sufficient penetration. These findings support the relevance of dynamic beam shaping to adapt the energy distribution along the weld.

These results demonstrate that beam shaping enables material- and configuration-specific solutions, with limited transferability between applications.