Improving laser welding quality for multi-layer Al tabs and collector disc via vacuum environment

To address inconsistent penetration depth and spatter during laser welding of multi-layer tabs to the current collector disc, this study proposed a vacuum laser welding strategy. Reducing ambient pressure to 10 Pa suppressed plasma shielding and weakened the molten pool vortices behind the keyhole, thereby improving keyhole stability. Consequently, penetration depth fluctuations decreased, and the weld surface became smooth and free of spatter. The combination of increased penetration depth, grain coarsening, and higher LAGBs fraction led to a 6.1% increase in joint strength and a 10.1% reduction in electrical resistance. This strategy offers a reliable solution for high-reflectivity multi-layer tab-to-disc connections in battery manufacturing.