Abstract: A novel welding method using adjustable-ring mode (ARM) scanning laser was applied to join 0.66mm-thick 304 stainless steel cylindrical lithium battery shell with 0.4mm-thick TU2 oxygen-free copper busbar. The effects of process parameters on the weld morphology and mechanical properties of the negative busbar were investigated. The results indicate that compared with non-scanning laser, the ARM scanning laser significantly increases the weld width and current flow weld width, substantially enlarges the current flow area and tensile force. The ARM scanning laser is highly suitable for lithium battery busbar dissimilar metal sheets welding. Compared with conventional scanning laser, the ARM scanning laser produces more uniform and smoother weld surfaces, less spatters, and has higher current flow areas and tensile forces. With the increase of central power or ring power, the penetration, weld width, current flow weld width, current flow area and tensile force all exhibit increasing trends. As the scanning frequency increases, the penetration, weld width, current flow weld width, current flow area and tensile force exhibit a reducing trends. The increase of scanning diameter has little effect on current flow weld width and current flow area, while the tensile force has a slightly decrease. Analysis from current flow area and tensile force, the optimized parameters range for the ARM laser scanning welding: central power 1200 W-1400 W, ring power 600 W-1400 W, scanning frequency 400 Hz-500 Hz and scanning diameter 350 μm-500 μm.