End cover assembly, secondary battery, battery pack and electric device

1. A secondary battery, comprising:

a case comprising an opening;

an electrode assembly disposed in the case; and

an end cover assembly, wherein the end cover assembly is connected with the case to seal the opening, and the end cover assembly comprises:

an end cover comprising an electrode lead-out hole;

a first terminal comprising a first connecting section and a second connecting section disposed along a radial direction of the electrode lead-out hole;

a second terminal comprising a third connecting section, a fuse section and a fourth connecting section that are sequentially connected along the radial direction; along an axial direction of the electrode lead-out hole, an orthographic projection of the first connecting section and an orthographic projection of the third connecting section at least partially overlap with each other, one of the first connecting section and the third connecting section is configured to connect with a busbar, the other is configured to connect with an electrode assembly, and the fourth connecting section is configured to connect with the second connecting section; and

an insulating component, at least a part of which is located between the first connecting section and the third connecting section.

2. The secondary battery according to claim 1 , wherein the fuse section and the fourth connecting section form an integral structure.

3. The secondary battery according to claim 1 , wherein the insulating component extends between the fuse section and the first connecting section.

4. The secondary battery according to claim 1 , wherein an overcurrent capacity of the fuse section is smaller than overcurrent capacities of the third connecting section and the fourth connecting section.

5. The secondary battery according to claim 1 , wherein the second terminal is located at a side of the first terminal away from the end cover.

6. The secondary battery according to claim 5 , wherein the third connecting section comprises a convex portion protruding toward the first connecting section; and/or the first connecting section comprises an extending portion, which protrudes in a direction away from the third connecting section, wherein at least a part of the extending portion is located in the electrode lead-out hole.

7. The secondary battery according to claim 5 , wherein the end cover assembly further comprises a fixing component, wherein a part of the fixing component at a side of the third connecting section away from the first connecting section presses against an edge of the third connecting section and/or an edge of the fourth connecting section, so that the first terminal and the second terminal are fixed to the end cover through the fixing component.

8. The secondary battery according to claim 7 , wherein a part of the insulating component is located below the edge of the third connecting section and/or the edge of the fourth connecting section, and along the axial direction, an orthographic projection of the insulating component and an orthographic projection of the fixing component have an overlap area.

9. The secondary battery according to claim 5 , wherein the end cover assembly further comprises an insulating protection member, and a part of the insulating protection member is located at a side of the fuse section away from the first terminal and covers the fuse section.

10. The secondary battery according to claim 9 , wherein the insulating protection member covers the fourth connecting section.

11. The secondary battery according to claim 9 , wherein the insulating protection member further comprises an inserting portion, and the inserting portion extends into a gap formed by the third connecting section, the fuse section and the fourth connecting section.

12. The secondary battery according to claim 1 , wherein the first terminal is located at a side of the second terminal away from the end cover.

13. The secondary battery according to claim 12 , wherein the end cover assembly further comprises a sealing component, wherein the sealing component is disposed between the second terminal and the end cover and seals the electrode lead-out hole, and a part of the sealing component covers the fuse section.

14. The secondary battery according to claim 2 , wherein the insulating component extends between the fuse section and the first connecting section.

15. The secondary battery according to claim 14 , wherein an overcurrent capacity of the fuse section is smaller than overcurrent capacities of the third connecting section and the fourth connecting section.

16. The secondary battery according to claim 15 , wherein the second terminal is located at a side of the first terminal away from the end cover.

17. The secondary battery according to claim 6 , wherein the end cover assembly further comprises a fixing component, wherein a part of the fixing component at a side of the third connecting section away from the first connecting section presses against an edge of the third connecting section and/or an edge of the fourth connecting section, so that the first terminal and the second terminal are fixed to the end cover through the fixing component.

18. The secondary battery according to claim 6 , wherein the end cover assembly further comprises an insulating protection member, and a part of the insulating protection member is located at a side of the fuse section away from the first terminal and covers the fuse section.

19. A battery pack, comprising:

two or more secondary batteries according to claim 1 ; and

a busbar for connecting different secondary batteries.

20. An electric device comprising a secondary battery according to claim 1 .