The present disclosure relates to a welding device and a processing apparatus for a secondary battery current collector. The welding device includes: a welding head; and an anvil block. A welding station is disposed between the welding head and the anvil block. The welding device is configured to weld a foil to a portion of a composite current collector at the welding station. According to this solution, the foil can be used as a tab of the composite current collector by using the foil to connect with the composite current collector so as to output the current in the battery cell.