A battery top cover assembly includes a top cover sheet, a lower insulating member and a pole. The top cover sheet is provided with a mounting hole which penetrates the top and bottom of the top cover sheet, the lower insulating member is provided with a first through hole which penetrates the top and bottom of the lower insulating member and corresponds to the mounting hole, one end of the pole passes through the mounting hole and the first through hole and is pressed against a side of the lower insulating member facing away from the top cover sheet, a cavity is formed between the top cover sheet and the pole, and a vent portion is provided at the portion where the lower insulating member is pressed against the pole.