The upper surface of the fastener 80 is provided with a first convex portion 822. The upper surface of the fastener 80 is a surface of the fastener 80 farther away from the battery cell 400, and the first convex portion 822 is arranged around the outside of the through hole 821. When the through hole 821 and the electrode terminal 5 are disposed together, the first convex portion 822 protrudes from the electrode terminal 5 in a direction leaving the battery cell 400. The first convex portion 822 is provided, so that other structural components installed on the upper part of the electrode terminal 5 can directly act on the first convex portion, thereby reducing forces acting on the electrode terminal 5 and preventing the electrode terminal 5 from deforming. This further ensures that the fastener installed on the electrode terminal 5 and the fire prevention pipeline 70 installed to the fastener 80 are installed stably, improving the safety performance of the battery.