In some feasible implementations, the third weak zone 931 may be directly provided as a through hole, or may be provided in a way other than a through hole. For example, a low-melting-point material is used on the third weak zone 931, or thickness of the third weak zone 931 is reduced, so that the third weak zone 931 is destroyed by the emissions to form a through hole when the pressure relief mechanism 6 is actuated.

The protection part 92 is provided with a third depression 932. The third depression 932 is provided corresponding to the first depression, and the third weak zone 931 is provided in the third depression 932. A plurality of through holes are further provided in the third depression 932, and the through holes are provided on two sides of the third depression 932 along a central axis of the fire prevention pipeline 70. The buckle 812 of the fastener 80 runs through the through holes to fasten the fire prevention pipeline 70. At the same time, the third depression 932 may accommodate the condensed water formed by cooling of the hot air in the box body on the fire prevention pipeline 70 and the fire prevention medium. The third depression 932 and the buckle 812 of the fastener 80 may form an accommodating pool above each battery cell 400, for preventing the emissions and fire prevention medium from flowing into the electrode terminal 5 and adjacent battery cells.

In some feasible implementations, the fire prevention pipeline 70 may be bonded to the protection part 93; or the protection part 93 and the separation part 92 are fastened together, and the fire prevention pipeline 70 is fastened only to the fastener 80.