Secondary battery and vehicle

1. A secondary battery, comprising:

a top cover plate;

an electrode terminal disposed on the top cover plate;

at least one electrode assembly, wherein each of the at least one electrode assembly comprises a main body and a plurality of conductive portions extending from the main body, the plurality of conductive portions is stacked and forms a tab, and the main body is formed by winding a first electrode plate, a second electrode plate, and a separator disposed between the first electrode plate and the second electrode plate; and

a connecting piece for connecting the tab to the electrode terminal,

wherein the tab extends from a side of the main body viewed in a thickness direction of the secondary battery, and the tab is bent with respect to a height direction of the secondary battery and connected to the connecting piece.

2. The secondary battery according to claim 1 , wherein the main body comprises a winding-starting layer, which is a starting end of an innermost layer of the main body, and the tab extends from a side of the winding-starting layer viewed in the thickness direction of the secondary battery.

3. The secondary battery according to claim 1 , wherein the tab comprises a connecting portion for main body connected to the main body, an extending portion connected to the connecting piece, and a bending portion connected between the connecting portion for main body and the extending portion, and

wherein the extending portion extends along the thickness direction of the secondary battery, and the bending portion is bent with respect to the extending portion.

4. The secondary battery according to claim 3 , wherein the main body has a first side and a second side, the tab is provided at the first side, none of the tab is provided at the second side, and the bending portion and the connecting portion for main body are located at the first side.

5. The secondary battery according to claim 4 , wherein the at least one electrode assembly comprises two electrode assemblies arranged side by side in the thickness direction of the secondary battery, and the second sides of the two main bodies of the two electrode assemblies are adjacent to each other.

6. The secondary battery according to claim 5 , wherein the secondary battery further comprises a supporting piece disposed between the main body and the extending portion.

7. The secondary battery according to claim 6 , wherein the supporting piece has a bar-like structure, and the tab bypasses the supporting piece.

8. The secondary battery according to claim 7 , wherein at least a part of the supporting piece is attached to the main body.

9. The secondary battery according to claim 8 , wherein the supporting piece comprises a first portion and a second portion, and the first portion is disposed opposite to the electrode terminal;

wherein on a surface of the supporting piece facing toward the top cover plate, an edge of the first portion protrudes with respect to the second portion; and

wherein the first portion is attached to the main body, and the tab bypasses the second portion.

10. The secondary battery according to claim 7 , wherein the supporting piece comprises a first portion and a second portion, the first portion is disposed opposite to the electrode terminal, and the tab bypasses the second portion, and

wherein the second portion protrudes with respect to the first portion at a side of the supporting piece viewed in the thickness direction of the secondary battery.

11. The secondary battery according to claim 6 , wherein the supporting piece comprises a supporting portion and a guiding portion, and the guiding portion is connected to an end of the supporting portion and bent with respect to the supporting portion; and

wherein the supporting portion is attached to the extending portion, and the guiding portion is attached to the bending portion.

12. The secondary battery according to claim 11 , wherein the guiding portion comprises a middle section connected to the supporting portion and an inclination section connected to the middle section, the inclination section of the guiding portion is inclined with respect to the middle section, and the inclination section is attached to the connecting portion for main body.

13. The secondary battery according to claim 12 , wherein each portion of the supporting piece has a minimum thickness of 0.1 mm-5 mm, and the supporting piece has a Young's elastic modulus of 1000 MPa-10000 MPa.

14. The secondary battery according to claim 1 , wherein a ratio of a width of the conductive portion to a thickness of the conductive portion is in a range of 100-5000.

15. A vehicle, comprising:

a secondary battery comprising:

a top cover plate;

an electrode terminal disposed on the top cover plate;

at least one electrode assembly, wherein each of the at least one electrode assembly comprises a main body and a plurality of conductive portions extending from the main body, the plurality of conductive portions is stacked and forms a tab, and the main body is formed by winding a first electrode plate, a second electrode plate, and a separator disposed between the first electrode plate and the second electrode plate; and

a connecting piece for connecting the tab to the electrode terminal,

wherein the tab extends from a side of the main body viewed in a thickness direction of the secondary battery, and the tab is bent with respect to a height direction of the secondary battery and connected to the connecting piece.