Process Robustness of Laser Braze-Welded AlCu Connectors

Laser welding of dissimilar metals such as Aluminum and Copper, which is required for Li-ion battery joining, is challenging due to
the inevitable formation of the brittle and high electrical-resistant intermetallic compounds. Recent research has shown that by using a
novel technology, called laser braze-welding, the Al-Cu intermetallics can be minimized to achieve superior mechanical and electrical
joint performance. This paper investigates the robustness of the laser braze-welding process. Three product and process categories, i.e.
choice of materials, joint configurations, and process conditions, are studied. It is found that in-process effects such as sample
cleanness and shielding gas fluctuations have a minor influence on the process robustness. Furthermore, many pre-process effects, e.g.
design changes such as multiple layers or anodized base material can be successfully welded by process adaption. The minimization of
the interface gap is identified as the most significant influence of process stability.
The specimen were validated by mechanical lap
shear tests and metallographic analysis.