What is battery spot welding? Battery spot welding is a key process in the cylindrical cell battery pack assembly process, which usually refers to the use of resistance welding technology to weld the cell-to-cell busbar onto the cylindrical cells. It is very common to spot weld nickel-plated steel strips or pure nickel strips onto the poles of cylindrical cells such as 18650, 21700, 26650, 26700, ...