The battery cell 400 is provided with a pressure relief mechanism 6. The pressure relief mechanism 6 is configured to be actuated when internal pressure or temperature of the battery cell 400 reaches a threshold, to release the internal pressure. The fire prevention pipeline 70 is configured to discharge the fire prevention medium toward the battery cell 400 when the pressure relief mechanism 6 is actuated. To avoid that the pressure relief mechanism 6 is blocked and the pressure relief mechanism 6 is unable to be spouted open, and also to allow the fire prevention medium discharged from the fire prevention pipeline 70 to enter the battery cell 400 through the pressure relief mechanism 6, the fastener 80 is further provided with a first weak zone 811, configured to allow the emissions from the battery cell 400 to pass through the first weak zone 811 and destroy the fire prevention pipeline 70 when the pressure relief mechanism 6 is actuated, so that the fire prevention medium in the fire prevention pipeline 70 passes through the first weak zone 811 to the battery cell 400.