Composite copper foil and double-sided connecting structure thereof

Abstract

The utility model belongs to the technical field of lithium battery cathodes, and particularly relates to a composite copper foil and a double-sided connecting structure thereof. The composite copper foil comprises an upper copper foil layer, a composite base layer and a lower copper foil layer which are sequentially arranged from top to bottom; the edge of the composite copper foil is provided with a plurality of kerfs so as to form a plurality of edge tongues which are arranged in a line; and the plurality of side tongues are alternately connected to the upper and lower surfaces of the flat copper strip. According to the composite copper foil in the scheme, the structure that the side tongues are alternately connected with the upper surface and the lower surface of the flat copper strip is adopted, so that the two surfaces of the composite copper foil are electrically connected, good contact between the copper foil layers of the composite copper foil is realized, the contact resistance is minimized, and lossless electrical connection is realized; in actual use, the mechanical strength and the electrical conductivity of connection can be ensured through proper pressure fixation or adhesive assistance.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium battery cathodes, and specifically relates to a composite copper foil and a double-sided connection structure thereof. Background Art

[0002] The current collector of the negative electrode of lithium-ion batteries is usually made of copper foil, also known as electrolytic copper foil. Some electrolytic copper foils use composite copper foil, which has the advantages of high energy density and relatively low cost. However, the thickness of the composite copper foil is relatively thin, and the composite base layer in the composite copper foil is not conductive, which makes the copper foil layers on both sides of the composite base layer unable to conduct, increasing the internal resistance of the battery cathode.

[0003] In the prior art, a U-shaped current collector is generally used to conduct the copper foil on both sides of the composite copper foil. In this way, the current collector needs to be bent into a U shape, and then the composite copper foil needs to be inserted into the slot cavity of the U-shaped current collector, and then welded. The whole process is difficult to manufacture and the process is complicated, which is not conducive to large-scale industrial applications. For example, the patent with application number "202311089213.1" adopts a multi-layer plating method to improve the safety of the battery; in the patent with application number "202311180416.1", a composite copper foil with advantages such as superior heat dissipation performance, stability and safety is produced by optimizing the processing technology. The patent with application number "CN202410045719.0" mentions conducting the two sides of the traditional composite copper foil through a conductive current collector, but does not provide a conduction method other than the U-shaped current collector, and the conduction diagram is only applicable to the field of lithium-ion batteries, and does not explore the specific front and rear surface connection method and the application in more fields.

[0004] None of the above technologies solves the problem of difficulty in conducting the copper foils on both sides of the composite copper foil, which limits the large-scale application of the composite copper foil. Therefore, it is necessary to design a double-sided connection structure with low manufacturing difficulty and simple process. Utility Model Content

[0005] In order to solve the above problems existing in the prior art, the present invention provides a composite copper foil and a double-sided connection structure thereof.

[0006] The technical solution adopted by the utility model is:

[0007] A double-sided connection structure of a composite copper foil comprises a flat copper strip and an edge tongue; the composite copper foil comprises an upper copper foil layer, a composite base layer and a lower copper foil layer arranged in sequence from top to bottom; a plurality of slits are arranged at the edge of the composite copper foil to form a plurality of edge tongues arranged in a straight line; a plurality of the edge tongues are alternately connected to the upper and lower surfaces of the flat copper strip.

[0008] As an alternative or supplement to the above-mentioned double-sided connection structure: the slits intersect with the edges of the composite copper foil perpendicularly, and the edge tongues are formed between adjacent slits.

[0009] As an alternative or supplement to the above-mentioned double-sided connection structure: perforations are further provided at the edges of the composite copper foil, and the perforations correspond to and intersect with the slits one by one.

[0010] As an alternative or supplement to the above-mentioned double-sided connection structure: the composite base layer is made of insulating thermal conductive material.

[0011] As an alternative or supplement to the above-mentioned double-sided connection structure: the thickness of the flat copper strip is H, 1um≤H≤50um.

[0012] A double-sided connection structure of a composite copper foil comprises an edge tongue; the composite copper foil comprises an upper copper foil layer, a composite base layer and a lower copper foil layer arranged in sequence from top to bottom; a plurality of slits are arranged at the edge of the composite copper foil to form a plurality of edge tongues arranged in a straight line; the outer end of the edge tongue is stretched in a direction perpendicular to the slits so that the edge tongue is deformed into a trapezoid; adjacent edge tongues are connected by being staggered and overlapped up and down.

[0013] A composite copper foil has one of the two double-sided connection structures arranged at the edge of the composite copper foil.

[0014] The beneficial effects of the utility model are:

[0015] 1. The composite copper foil in this scheme adopts a structure in which the edge tongues alternately connect the upper and lower surfaces of the flat copper strip to achieve electrical connection between the two sides of the composite copper foil, achieve good contact between the copper foil layers of the composite copper foil, minimize contact resistance, and achieve lossless electrical connection; in actual use, appropriate pressure fixation or adhesive assistance can be used to ensure the mechanical strength and electrical conductivity of the connection.

[0016] 2. The process of cutting the edge of the composite copper foil, alternately bending it up and down, and clamping the flat copper strip in this solution is simpler and less difficult than the process of connecting the U-shaped current collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below.

[0018] Figure 1 It is a structural schematic diagram of the double-sided connection structure of the composite copper foil in this scheme;

[0019] Figure 2 (a) and (b) are the before and after images of the flat copper strip being installed on the composite copper foil;

[0020] Figure 3 (a) and (b) are the before and after images of the flat copper tape being installed on the composite copper foil with perforations;

[0021] Figure 4(a) and (b) are the state diagrams of the edge tongue of the composite copper foil before and after overlapping;

[0022] Figure 5 middle Figure 4 Schematic diagram of the cross-sectional structure of the local M in the figure.

[0023] In the figure: 1-upper copper foil layer; 2-composite base layer; 3-lower copper foil layer; 4-flat copper strip; 5-edge tongue; 6-slit; 7-perforation. DETAILED DESCRIPTION

[0024] The technical solution in this embodiment will be clearly and completely described below in conjunction with the accompanying drawings. The described embodiments are only some of the embodiments, not all of them. Based on the embodiments in this solution, all other embodiments obtained by ordinary technicians in this field without making creative work are within the protection scope of this solution.

[0025] Example 1

[0026] like Figures 1 to 3 As shown, this embodiment designs a double-sided connection structure of a composite copper foil, including a flat copper strip 4 and an edge tongue 5.

[0027] The composite copper foil is in the shape of foil strip as a whole, and comprises an upper copper foil layer 1, a composite base layer 2 and a lower copper foil layer 3 arranged in sequence from top to bottom. The composite base layer 2 generally adopts insulating thermal conductive material, which can be selected from existing polymer materials.

[0028] The edge of the composite copper foil is cut into a plurality of slits 6 by a cutting process. The slits 6 intersect the edge of the composite copper foil perpendicularly and form edge tongues 5 between adjacent slits 6. The width of the edge tongue 5 is generally 2-5 mm. The length of the slits 6 is generally 3-10 mm.

[0029] Several side tongues 5 are arranged in a straight line. When the flat copper strip 4 needs to be connected, the side tongues 5 spaced apart from each other are first bent upward, and then the flat copper strip 4 is placed on the remaining unbent side tongues 5, and then the side tongues 5 bent upward are bent downward, so that several side tongues 5 are alternately connected to the upper and lower surfaces of the flat copper strip 4. In this state, the lower surface of the side tongue 5 of the lower copper foil layer 3 can be connected to the upper surface of the flat copper strip 4, and the upper surface of the side tongue 5 of the upper copper foil layer 1 can be connected to the lower surface of the flat copper strip 4, so as to achieve good contact between the copper foil layers of the composite copper foil, minimize contact resistance, and achieve lossless electrical connection; in actual use, appropriate pressure fixation or adhesive can be used to ensure the mechanical strength and electrical conductivity of the connection.

[0030] The thickness of the flat copper strip 4 is H, 1um≤H≤50um.

[0031] In addition, a perforation 7 may be provided at the edge of the composite copper foil. Figure 3 As shown, the perforations 7 correspond to and intersect the slits 6 one by one, so that the perforations 7 are used to protect the slits 6 and reduce the possibility of tearing of the slits 6 during the bending of the side tongue 5.

[0032] Example 2

[0033] like Figure 4 and Figure 5 As shown, this embodiment is designed to hollow out a double-sided connection structure of a composite copper foil, including an edge tongue 5.

[0034] The composite copper foil is in the shape of foil strip as a whole, and comprises an upper copper foil layer 1, a composite base layer 2 and a lower copper foil layer 3 arranged in sequence from top to bottom. The composite base layer 2 generally adopts insulating thermal conductive material, which can be selected from existing polymer materials.

[0035] The edge of the composite copper foil is cut into a plurality of slits 6 by a cutting process. The slits 6 intersect the edge of the composite copper foil perpendicularly and form edge tongues 5 between adjacent slits 6. The width of the edge tongue 5 is generally 2-5 mm. The length of the slits 6 is generally 3-10 mm.

[0036] Several side tongues 5 are arranged in a straight line, and the side tongues 5 are stretched. Specifically, the outer end of the side tongue 5 is stretched in a direction perpendicular to the slit 6, so that the side tongue 5 is deformed into a trapezoid; adjacent side tongues 5 are staggered and overlapped in an upper and lower manner, so that the upper copper foil layer 1 at the side tongue 5 can be attached to the lower copper foil layer 3 of the other side tongue 5.

[0037] Example 3

[0038] This embodiment designs a composite copper foil, and a double-sided connection structure in Embodiment 1 or Embodiment 2 is arranged at the edge of the composite copper foil.

[0039] The above embodiments are merely examples for the purpose of clarifying the description, and are not intended to limit the implementation methods; it is not necessary and impossible to list all implementation methods exhaustively. However, obvious changes or modifications derived therefrom are still within the scope of protection of the present technology.

Claims

1. A double-sided connection structure of a composite copper foil, characterized in that: The invention comprises a flat copper strip (4) and an edge tongue (5); the composite copper foil comprises an upper copper foil layer (1), a composite base layer (2) and a lower copper foil layer (3) arranged in sequence from top to bottom; a plurality of slits (6) are arranged at the edge of the composite copper foil to form a plurality of edge tongues (5) arranged in a straight line; the plurality of edge tongues (5) are alternately connected to the upper and lower surfaces of the flat copper strip (4).

2. The double-sided connection structure of the composite copper foil according to claim 1, characterized in that: The slits (6) intersect vertically with the edges of the composite copper foil, and the edge tongues (5) are formed between adjacent slits (6).

3. The double-sided connection structure of the composite copper foil according to claim 2, characterized in that: Perforations (7) are also provided at the edge of the composite copper foil, and the perforations (7) correspond to and intersect with the slits (6) one by one.

4. The double-sided connection structure of the composite copper foil according to claim 1, characterized in that: The composite base layer (2) is made of insulating heat-conductive material.

5. The double-sided connection structure of the composite copper foil according to claim 1, characterized in that: The thickness of the flat copper strip (4) is H, 1um≤H≤50um.

6. A composite copper foil, characterized in that: A double-sided connection structure as claimed in any one of claims 1 to 5 is arranged at the edge of the composite copper foil.

7. A double-sided connection structure of a composite copper foil, characterized in that: The invention comprises an edge tongue (5); the composite copper foil comprises an upper copper foil layer (1), a composite base layer (2) and a lower copper foil layer (3) arranged in sequence from top to bottom; a plurality of slits (6) are arranged at the edge of the composite copper foil to form a plurality of edge tongues (5) arranged in a straight line; the outer end of the edge tongue (5) is stretched in a direction perpendicular to the slits (6) so that the edge tongue (5) is deformed into a trapezoid; and adjacent edge tongues (5) are connected by being staggered and overlapped up and down.

8. A composite copper foil, characterized in that: The double-sided connection structure according to claim 7 is arranged at the edge of the composite copper foil.

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