Battery unit and manufacturing method thereof, and battery module

1. A battery unit, comprising:

an electrode assembly, comprising a main body portion, a negative tab and a positive tab, wherein the negative tab and the positive tab respectively extend out from both ends of the main body portion along a length direction of the electrode assembly;

a negative terminal and a positive terminal, arranged at the top of the electrode assembly; and

a first current collector and a second current collector, wherein the first current collector electrically connects the negative tab with the negative terminal, and the second current collector electrically connects the positive tab with the positive terminal;

wherein the first current collector comprises a first guiding plate, the first guiding plate is of a flat plate structure, and is provided with no bending structure at both ends along a width direction of the electrode assembly, the first guiding plate is located on one side of the main body portion adjacent to the negative terminal along the length direction and extends along the width direction of the electrode assembly, and the negative tab is singly bent to one side of the first guiding plate away from the main body portion and is connected with the first guiding plate.

2. The battery unit according to claim 1 , comprising two electrode assemblies, wherein the negative tab of one electrode assembly is led out from one side of the main body portion away from the other electrode assembly along the width direction, and the negative tabs of the two electrode assemblies are bent towards each other along the width direction.

3. The battery unit according to claim 1 , wherein the second current collector comprises a second guiding plate, the second guiding plate is of a flat plate structure, the second guiding plate is located on one side of the main body portion adjacent to the positive terminal along the length direction and extends along the width direction, and the positive tab is bent to one side of the second guiding plate away from the main body portion and is connected with the second guiding plate.

4. The battery unit according to claim 1 , wherein the second current collector comprises a second guiding plate and a supporting plate, the second guiding plate is located on one side of the main body portion adjacent to the positive terminal along the length direction and extends along the width direction, the supporting plate is connected to an end of the second guiding plate along the width direction, and the positive tab is connected to the supporting plate from the outer side and is entirely bent to one side of the second guiding plate away from the main body portion.

5. The battery unit according to claim 4 , wherein supporting plates are arranged on both ends of the second guiding plate along the width direction, and the two supporting plates are bent towards each other.

6. The battery unit according to claim 4 , wherein,

the supporting plate offsets inward for a predetermined distance with respect to the edge of the end of the second guiding plate along the width direction; and/or

the edge of a free end of at least one of the first guiding plate and the second guiding plate along the width direction offsets inward for a predetermined distance on at least partial height, so as to form a first notch, and the negative tab or the positive tab passes through the first notch.

7. The battery unit according to claim 4 , wherein the second current collector further comprises a second adapter plate, the positive terminal is fixed to the second adapter plate, a side of the supporting plate adjacent to the second adapter plate and the second adapter plate are arranged at intervals, and a second notch is formed at an end of a connection portion of the second guiding plate and the supporting plate adjacent to the second adapter plate.

8. The battery unit according to claim 1 , wherein both of the negative tab and the positive tab are of layered structures; and the negative tab comprises a first connecting portion and a first collecting portion, the first connecting portion is located on one side of the first guiding plate away from the main body portion along the length direction and is connected to the first guiding plate, the first collecting portion is located on one side of the first guiding plate adjacent to the main body portion along the length direction, and the first guiding plate is attached to the first collecting portion.

9. The battery unit according to claim 8 , wherein,

the first guiding plate comprises a substrate layer, and the substrate layer is attached to the first collecting portion; or

the first guiding plate comprises a substrate layer and an insulating layer, the insulating layer is attached to one side of the substrate layer adjacent to the first collecting portion, and the insulating layer is attached to the first collecting portion.

10. The battery unit according to claim 8 , wherein each layer of the first connecting portion is integrally formed by ultrasonic welding and forms a first fusion area, the first connecting portion and the first guiding plate are fixed by laser welding and form a second fusion area, in a plane perpendicular to the length direction, and the projection of the second fusion area is completely located in a projection area of the first fusion area.

11. The battery unit according to claim 1 , wherein the hardness of the first current collector is greater than the hardness of the second current collector.

12. A battery module, comprising:

a fixing frame; and

a plurality of battery units according to claim 1 , arranged in the fixing frame and arranged side by side along the width direction.

13. A manufacturing method of the battery unit according to claim 1 , comprising:

preparing the electrode assembly;

fixing the negative terminal and the positive terminal to the first current collector and the second current collector respectively;

bending the negative tab and connecting the same with the first guiding plate; and

bending the positive tab and connecting the same with the second current collector.

14. The manufacturing method of the battery unit according to claim 13 , wherein,

the step of bending the negative tab and connecting the same with the first guiding plate comprises:

making each piece of the negative tabs form an entirety through ultrasonic welding;

bending the welded negative tab to one side of the first guiding plate away from the main body portion, and attaching the negative tab to the first guiding plate; and

performing laser welding on the negative tab and the first guiding plate from the outer side of the negative tab.

15. The manufacturing method of the battery unit according to claim 13 , wherein the step of bending the negative tab and connecting the same with the first guiding plate comprises:

placing a side of the main body portion perpendicular to the width direction in parallel with the first guiding plate, and attaching an inner side of the negative tab to an outer side of the first guiding plate;

placing a supporting member on the inner side of the first guiding plate;

performing ultrasonic welding on the negative tab and the first guiding plate from the outer side of the negative tab; and

rotating the main body portion by 90° around the root of the negative tab to bend the negative tab after welding.

16. The manufacturing method of the battery unit according to claim 13 , wherein the second current collector comprises a second guiding plate and a supporting plate, the supporting plate is connected to the end of the second guiding plate along the width direction, and the step of bending the positive tab and connecting the same with the second current collector comprises:

placing a supporting member on the inner side of the supporting plate;

performing ultrasonic welding on the positive tab and the supporting plate from the outer side of the positive tab; and

bending the entirety of the welded positive tab and the supporting plate to one side of the second guiding plate away from the main body portion.

17. The manufacturing method of the battery unit according to claim 16 , wherein the negative tab and the first guiding plate are ultrasonically welded, and the welding step of the negative tab is performed before the welding step of the positive tab.

18. The manufacturing method of the battery unit according to claim 13 , wherein the second current collector comprises a second guiding plate, the positive tab is of a flat plate structure, and the positive tab is bent to one side of the second guiding plate away from the main body portion and is fixedly connected with the second guiding plate;

laser welding is performed between the negative tab and the first guiding plate and between the positive tab and the second guiding plate; or

the laser welding is performed on one of the locations between the negative tab and the first guiding plate and between the positive tab and the second guiding plate, the ultrasonic welding is performed on the other one, and the ultrasonic welding is performed before the laser welding.