The upper surface of the fastener 80, that is, a surface farther away from the battery cell 400, is provided with a stiffener structure 814. The main body 81 is further provided with a first depression, and the stiffener structure 814 of the main body 81 is provided on the outside of the first depression. The first weak zone 811 and the buckle 812 are both located in the first depression. The first depression can accommodate at least part of the fire prevention pipeline 70, for example, at least part of the bottom of the fire prevention pipeline 70.

In some feasible implementations, when the buckle 812 is located in the first depression, the buckle 812 and the first depression may form an accommodating pool for accommodating liquid. For example, when the pressure relief structure 6 is actuated, the first depression can be configured to block the emissions and fire prevention medium from flowing in the direction toward the electrode terminals 5 on two sides of the main body 81, and the buckle 812 can block the emissions and fire prevention medium from flowing along an axial direction of the fire prevention pipeline 70, to effectively prevent the emissions and fire prevention medium from entering adjacent battery cells.

In some embodiments, the fastener 80 may be a plastic part. The plastic part may be produced by integral injection molding at a high efficiency.