COMPOSITE CURRENT COLLECTOR, ELECTRODE SHEET, SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK, AND ELECTRICAL APPARATUS
A composite current collector includes a support layer and a conductive layer. The support layer has two surfaces opposite to each other along a thickness direction. The conductive layer is provided on the two surfaces and includes a first portion and a second portion. The first portion includes a first sub-portion and a second sub-portion provided on the two surfaces, respectively. The second portion includes a third sub-portion and a fourth sub-portion. The third sub-portion and the first sub-portion are integrally provided. The fourth sub-portion and the second sub-portion are integrally provided. The third sub-portion and the fourth sub-portion both project from the support layer. The third sub-portion and the fourth sub-portion are affixed to each other and fused as a whole.
1 . A composite current collector, comprising:
a support layer having two surfaces opposite to each other along a thickness direction; and
a conductive layer provided on the two surfaces, the conductive layer comprising a first portion and a second portion, wherein:
the first portion comprises a first sub-portion and a second sub-portion provided on the two surfaces, respectively;
the second portion comprises a third sub-portion and a fourth sub-portion;
the third sub-portion and the first sub-portion are integrally provided;
the fourth sub-portion and the second sub-portion are integrally provided;
the third sub-portion and the fourth sub-portion both project from the support layer along a first direction; and
the third sub-portion and the fourth sub-portion are affixed to each other and fused as a whole.
2 . The composite current collector according to claim 1 , wherein:
the third sub-portion, an end portion of the support layer along the first direction, and the fourth sub-portion are affixed to each other and fused as a whole.
3 . The composite current collector according to claim 2 , wherein:
the end portion along the first direction has a width of 1 mm to 10 mm.
4 . The composite current collector according to claim 1 , wherein:
the two surfaces are two first surfaces; and
the third sub-portion comprises two second surfaces opposite to each other along the thickness direction, and the first sub-portion projects with respect to the second surfaces along the thickness direction.
5 . The composite current collector according to claim 1 , wherein:
the two surfaces are two first surfaces;
the third sub-portion comprises two second surfaces opposite to each other along the thickness direction; and
the first sub-portion comprises two third surfaces opposite to each other along the thickness direction, one of the two third surfaces being flush with one of the two second surfaces.
6 . The composite current collector according to claim 1 , wherein:
the first portion has a thickness of A and the second portion has a thickness of B, wherein 0.03≤A/B≤1.
7 . The composite current collector according to claim 1 , wherein:
a thickness of the first sub-portion is greater than or equal to a thickness of the second sub-portion; and/or
a thickness of the third sub-portion is greater than or equal to a thickness of the fourth sub-portion.
8 . The composite current collector according to claim 1 , wherein:
the second portion further comprises a connecting layer disposed between the third sub-portion and the fourth sub-portion, and a melting point of the connecting layer is less than a melting point of the third sub-portion.
9 . The composite current collector according to claim 8 , wherein:
the connecting layer comprises at least one of a metal layer or an organic conductive polymer layer.
10 . The composite current collector according to claim 8 , wherein:
the connecting layer comprises at least one of tin, indium, bismuth and cadmium.
11 . The composite current collector according to claim 8 , wherein:
the connecting layer comprises at least one of polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene, or polyphenylene acetylene.
12 . The composite current collector according to claim 8 , wherein:
The connecting layer has a thickness of 1 μm to 5 μm.
13 . A manufacturing method for a composite current collector, comprising:
providing a support layer that comprises two surfaces opposite to each other along a thickness direction;
providing a first conductive sheet and a second conductive sheet, and connecting the first conductive sheet and the second conductive sheet to the two surfaces, respectively, wherein:
the first conductive sheet comprises a first sub-portion;
the second conductive sheet comprises a second sub-portion;
the first conductive sheet further comprises a third sub-portion;
the second conductive sheet further comprises a fourth sub-portion;
the first sub-portion and the second sub-portion are provided on the two surfaces, respectively; and
the third sub-portion and the fourth sub-portion both project from the support layer; and
affixing the third sub-portion and the fourth sub-portion to each other and fusing the third sub-portion and the fourth sub-portion as a whole.
14 . The method according to claim 13 , further comprising:
removing part of the first sub-portion along the thickness direction to thin the first sub-portion.
15 . The method according to claim 13 , further comprising:
removing part of the third sub-portion along the thickness direction to thin the third sub-portion.
16 . An electrode sheet, comprising:
a composite current collector comprising:
a support layer having two surfaces opposite to each other along a thickness direction; and
a conductive layer provided on the two surfaces, the conductive layer comprising a first portion and a second portion, wherein:
the first portion comprises a first sub-portion and a second sub-portion provided on the two surfaces, respectively;
the second portion comprises a third sub-portion and a fourth sub-portion;
the third sub-portion and the first sub-portion are integrally provided;
the fourth sub-portion and the second sub-portion are integrally provided;
the third sub-portion and the fourth sub-portion both project from the support layer along a first direction; and
the third sub-portion and the fourth sub-portion are affixed to each other and fused as a whole; and
an active material layer provided on a surface of the first portion of the composite current collector.
17 . A secondary battery, comprising the electrode sheet according to claim 16 .
18 . A battery module, comprising the secondary battery according to claim 17 .
19 . A battery pack, comprising the secondary battery according to claim 17 .
20 . An electrical apparatus, comprising the secondary battery according to claim 17 .