COMPOSITE CURRENT COLLECTOR, SECONDARY BATTERY, AND ELECTRIC APPARATUS
A composite current collector includes a first metal layer, a second metal layer, and a first binding layer. The first metal layer includes a first body zone and a first tab zone. The first tab zone is located at an end of the first metal layer. The second metal layer includes a second body zone and a second tab zone. The second tab zone is located at an end of the second metal layer. The first body zone and the second body zone are connected through the first binding layer. The first tab zone has a thickness greater than thickness of the first body zone. The first tab zone extends toward the second tab zone.
1 . A composite current collector, comprising:
a first metal layer;
a second metal layer; and
a first binding layer;
wherein:
the first metal layer comprises a first body zone and a first tab zone, the first tab zone being located at an end of the first metal layer;
the second metal layer comprises a second body zone and a second tab zone, the second tab zone being located at an end of the second metal layer;
the first body zone and the second body zone are connected through the first binding layer;
the first tab zone has a thickness greater than thickness of the first body zone; and
the first tab zone extends toward the second tab zone.
2 . The composite current collector according to claim 1 , wherein a first groove is provided at an end of the first tab zone extending toward the second tab zone, the first groove extending from one side of the first tab zone close to the first body zone to another side.
3 . The composite current collector according to claim 2 , wherein the second tab zone has a thickness greater than thickness of the second body zone and the second tab zone extends toward the first tab zone.
4 . The composite current collector according to claim 3 , wherein a second groove is provided at an end of the second tab zone extending toward the first tab zone, the second groove extending from one side of the second tab zone close to the second body zone to another side.
5 . The composite current collector according to claim 4 , wherein a second binding layer is provided between the first tab zone and the second tab zone, the second binding layer at least partially filling a gap between the first tab zone and the second tab zone.
6 . The composite current collector according to claim 5 , wherein the second binding layer has a thickness of 0.5 μto 5 μat the first groove and/or the second groove, and the second binding layer has a thickness of less than 0.5 μat other parts.
7 . The composite current collector according to claim 5 , wherein a ratio of total thickness of the first tab zone and the second tab zone to thickness of the second binding layer at the first groove and/or the second groove is greater than or equal to 2.
8 . The composite current collector according to claim 5 , wherein the composite current collector satisfies at least one of the following conditions (1) to (4):
(1) a ratio of width of the first groove to width of the first tab zone is 0.05 to 0.5;
(2) a ratio of width of the second binding layer at the first groove to width of the first tab zone is 0.05 to 0.5;
(3) a ratio of width of the second groove to width of the second tab zone is 0.05 to 0.5; or
(4) a ratio of width of the second binding layer at the second groove to width of the second tab zone is 0.05 to 0.5.
9 . The composite current collector according to claim 5 , wherein the composite current collector satisfies at least one of the following conditions (5) to (8):
(5) the side of the second tab zone close to the second body zone is in contact with the first binding layer;
(6) the first tab zone is connected to the second tab zone;
(7) the second binding layer is connected to the first binding layer; or
(8) the side of the first tab zone close to the first body zone is in contact with the first binding layer.
10 . The composite current collector according to claim 1 , wherein:
the first metal layer comprises a plurality of first body zones, the plurality of first body zones being spaced apart by third tab zones;
the second metal layer comprises a plurality of second body zones, the plurality of second body zones being spaced apart by fourth tab zones; and
the third tab zone has a thickness greater than thickness of the first body zone, and the third tab zone extends toward the fourth tab zone.
11 . The composite current collector according to claim 10 , wherein the composite current collector satisfies at least one of the following conditions (9) to (11):
(9) the fourth tab zone has a thickness greater than the thickness of the second body zone, and the fourth tab zone extends toward the third tab zone;
(10) a side wall of the fourth tab zone is in contact with the first binding layer; or
(11) the third tab zone is connected to the fourth tab zone.
12 . The composite current collector according to claim 10 , wherein the composite current collector satisfies at least one of the following conditions (12) to (14):
(12) a third binding layer is provided between the third tab zone and the fourth tab zone, the third binding layer at least partially filling a gap between the third tab zone and the fourth tab zone;
(13) the third binding layer is connected to the first binding layer; or
(14) a side wall of the third tab zone is in contact with the first binding layer.
13 . The composite current collector according to claim 12 , wherein the third binding layer has a thickness of 0.5 μto 5 μm.
14 . The composite current collector according to claim 10 , wherein a sum of thicknesses of the third tab zone and the fourth tab zone is greater than or equal to 7 μm.
15 . The composite current collector according to claim 10 , wherein the sum of thicknesses of the third tab zone and the fourth tab zone is 5 μto 13 μgreater than the sum of thicknesses of the first body zone and the second body zone.
16 . The composite current collector according to claim 1 , wherein a sum of thicknesses of the first tab zone and the second tab zone is greater than or equal to 7 μm.
17 . The composite current collector according to claim 1 , wherein the sum of thicknesses of the first tab zone and the second tab zone is 5 μto 13 μgreater than a sum of thicknesses of the first body zone and the second body zone.
18 . The composite current collector according to claim 1 , wherein the first binding layer comprises a binder and one or more of a particulate material and a conductive agent.
19 . The composite current collector according to claim 18 , wherein the composite current collector satisfies at least one of the following conditions (15) to (18):
(15) the particulate material comprises one or more of inorganic compound particles and metal particles;
(16) the conductive agent comprises one or more of carbon nanotubes, conductive carbon, graphene, and conductive polymers;
(17) a sum of the mass percentages of the particulate material and conductive agent in the first binding layer is 20% to 70%; and
(18) the binder comprises one or more of polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, carboxylic acid and its derivative graft polyethylene, polypropylene, carboxylic acid and its derivative graft polypropylene, polypropylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polymethyl methacrylate, polyethylene glycol, polysulfide nitride, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin.
20 . A secondary battery, comprising the composite current collector according to claim 1 .