Provided are a battery module and an electrode tab ultrasonic wave welding method. The present invention relates to a battery module and an electrode tab ultrasonic wave welding method by forming the electrode tab in a zigzag form in which the electrode tab extending upwardly is bent downwardly and then, again bent upwardly to allow the electrode tab formed in the zigzag form to absorb vibrations even when a welding portion formed in parallel with a battery cell is fused by ultrasonic wave vibrations, thereby minimizing damage to the battery cell.