In the domain of new energy vehicles, the control of welding deformation in aluminum alloy battery systems poses substantial challenges. The existing methodologies for diminishing welding deformation, such as laser segmented skip welding, alteration of welding path sequences, numerical simulation prediction, and post-weld heat treatment, still possess room for further optimization when applied to intricate welding structures. In this research, a novel adjustable-ring-mode laser in conjunction with the oscillation welding technique was employed to explore the impacts of fiber core diameter, laser light field brightness distribution, and process parameters on weld formation. The regulation of welding deformation was achieved through optimizing the welding process and adjusting the welding path. The results indicate that when the fiber core diameter is 50/150 mu m and the light field brightness distribution is H, the weld size exhibits the highest stability. Under the conditions of process parameters p = 5300 W, v = 5.4 m/min, A = 1.6 mm, f = 120 Hz, and theta = 40 degrees, and with the spot position located at the bottom of the side of the upper substrate, the optimal weld formation is obtained. After optimizing the welding path, the maximum Z-direction deformation of the weld is 1.403 mm, representing a reduction of 1.702 mm compared to the previous value. This work is capable of providing novel theoretical guidance and technical insights for the control of welding deformation in thin aluminum alloy plates.