Automatic Single-Side Rotary Head Numerical Control Spot Welding Machine Welder For 18650/21700 Battery Pack Assembly Description Automatic battery spot welding machines play a key role in cylindrical battery pack assembly lines. When multiple cells are connected in series or in parallel to form a battery pack, the spot welding machine can quickly and accurately weld the tabs of the battery cells to the connecting pieces (such as nickel sheets), thereby forming a battery pack