The invention relates to a battery terminal welding device comprising a battery conveying device, a battery terminal conveying device, a battery terminal grabbing device and a battery terminal welding mechanism. The battery conveying device is used for conveying a battery workpiece to a machining station. The battery terminal conveying device is used for conveying a battery terminal to a grabbing station. The battery terminal grabbing device is used for grabbing the battery terminal on the grabbing station and moving and arranging the battery terminal onto the battery workpiece, so that a battery electrode column of the battery workpiece is sleeved with an electrode column hole of a first welding plate of the battery terminal. The battery terminal welding mechanism is used for welding the battery electrode column and the first welding plate together. According to the battery terminal welding device, the battery terminal can be welded to the battery electrode column of the battery workpiece by matching the battery conveying device, the battery terminal conveying device, the battery terminal grabbing device and the battery terminal welding mechanism, manual operation of workers is not needed, the automation degree is high, and labor cost is lowered.