Secondary battery

1. A secondary battery, comprising a first electrode assembly, a second electrode assembly, a case and a top cap assembly;

the first electrode assembly and the second electrode assembly are housed in the case;

the top cap assembly comprises a top cap plate and a first electrode terminal, the top cap plate is connected to the case, and the first electrode terminal is arranged on the top cap plate;

the first electrode assembly comprises a first body and first tabs extending from the first body, and the first tabs are multiple and stacked;

the second electrode assembly comprises a second body and second tabs extending from the second body, and the second tabs are multiple and stacked;

the second tabs are bent toward a direction approaching the first tabs and connected to the first tabs, and an end of each of the second tabs that is away from the second body is a second end portion;

each of the first tabs comprises a first connecting portion extending beyond the second end portions of the second tabs, and the first connecting portion is connected to the first electrode terminal.

2. The secondary battery according to claim 1 , wherein

each of the first tabs further comprises a first extending portion, the first extending portion is connected between the first connecting portion and the first body, and the second tabs are welded to first extending portions of the first tabs.

3. The secondary battery according to claim 2 , wherein

each of the second tabs further comprises a second extending portion and a second connecting portion, the second extending portion is connected to the second body and extends toward a direction approaching the first extending portion of the first tab, and the second connecting portion extends from an end of the second extending portion that is away from the second body, and is welded to the first extending portion of the first tab.

4. The secondary battery according to claim 3 , wherein second connecting portions of the second tabs are welded to the first extending portions of the multiple first tabs to form a first welded region.

5. The secondary battery according to claim 4 , wherein

the secondary battery further comprises an adapter piece, and the adapter piece is connected to the first electrode terminal;

first connecting portions of the first tabs are welded to the adapter piece to form a second welded region, and an area of the second welded region is greater than or equal to an area of the first welded region.

6. The secondary battery according to claim 1 , wherein

the first tabs are arranged on a side of a thickness center of the first electrode assembly;

the second tabs are arranged on a side of a thickness center of the second electrode assembly;

the first tabs are arranged close to an interface between the first electrode assembly and the second electrode assembly and the second tabs are arranged away from the interface between the first electrode assembly and the second electrode assembly, or, the second tabs are arranged close to the interface between the first electrode assembly and the second electrode assembly and the first tabs are arranged away from the interface between the first electrode assembly and the second electrode assembly.

7. The secondary battery according to claim 6 , wherein the first tabs are arranged on a side of the thickness center of the first electrode assembly that is away from the interface.

8. The secondary battery according to claim 1 , wherein

the secondary battery further comprises a third electrode assembly and a fourth electrode assembly that are housed in the case, and the first electrode assembly, the second electrode assembly, the third electrode assembly and the fourth electrode assembly are sequentially arranged;

the third electrode assembly comprises a third body and third tabs extending from the third body, and the third tabs are multiple and stacked;

the fourth electrode assembly comprises a fourth body and fourth tabs extending from the fourth body, and the fourth tabs are multiple and stacked;

the third tabs are bent toward a direction approaching the fourth tabs and connected to the fourth tabs, and an end of each of the third tabs that is away from the third body is a third end portion;

each of the fourth tabs comprises a fourth connecting portion extending beyond the third end portion, and the fourth connecting portion is connected to the first electrode terminal.

9. The secondary battery according to claim 1 , wherein

the secondary battery further comprises a fifth electrode assembly, the fifth electrode assembly is housed in the case, and the fifth electrode assembly is arranged on a side of the second electrode assembly that is away from the first electrode assembly;

the fifth electrode assembly comprises a fifth body and fifth tabs extending from the fifth body, and the fifth tabs are bent toward a direction approaching the second tabs and welded to the second tabs.

10. The secondary battery according to claim 9 , wherein

the secondary battery comprises multiple fifth electrode assemblies sequentially arranged in a direction away from the second electrode assembly, and fifth tabs of each of the fifth electrode assemblies are bent toward a direction approaching the second tabs;

the fifth tabs of a fifth electrode assembly adjacent to the second electrode assembly are welded to the second tabs;

the fifth tabs of each of the other fifth electrode assemblies than the fifth electrode assembly adjacent to the second electrode assembly are welded to the fifth tabs of an adjacent fifth electrode assembly.