Composite conductive film

Abstract

The utility model discloses a composite conducting film, which belongs to the technical field of current collectors and comprises a supporting layer, a plurality of pores are arranged on the surface of the supporting layer to form a gas accommodating cavity, a conducting layer is arranged on at least one surface of the supporting layer, and the pores are partially filled with materials of the conducting layer. According to the composite conductive film provided by the utility model, the pores distributed at a certain density are formed on at least one surface of the composite conductive film to serve as the accommodating cavity, so that the vacuum hardening condition after follow-up rolling is slowed down.

Description

Technical Field

[0001] The utility model relates to the technical field of current collectors, in particular to a composite conductive film. Background Art

[0002] In secondary batteries, a current collector is needed as the part that gathers current. Its material is generally aluminum foil or copper foil. For safety reasons, the existing technology has proposed a composite conductive film, which includes a polymer support layer and metal layers arranged on both sides of the support layer.

[0003] In the prior art, copper foil is generally used as the negative electrode current collector of secondary batteries. At the same time, in order to improve energy density and safety, a composite current collector structure with a polymer as a support layer has been proposed.

[0004] At present, the composite current collector for the negative electrode is generally thickened based on water electroplating. There is a problem of film adhesion after winding, especially water electroplating copper. The coating adhesion is poor, and the coating is prone to fall off due to adhesion.

[0005] Further improvement and optimization are needed. Utility Model Content

[0006] The present invention aims to solve, at least to a certain extent, one of the technical problems in the related art. To this end, one object of the present invention is to provide a composite conductive film having pores with a certain density distribution on at least one surface thereof, which serve as accommodating cavities to reduce vacuum hardening after subsequent winding.

[0007] The technical solution of the utility model is as follows:

[0008] A composite conductive film includes a support layer, a surface of which is provided with a plurality of pores to form a gas accommodating cavity, and a conductive layer is provided on at least one surface of the support layer, wherein the conductive layer material partially fills the pores.

[0009] Based on the above technical solution, the vacuum compaction condition of the film after winding can be improved; the conductive layer material can also be partially filled in the pores during the deposition and thickening process, which can improve the overall strength of the support layer.

[0010] Further, the aperture is provided on at least one side of the support.

[0011] Based on the above technical solution, it is convenient to process the pores.

[0012] Furthermore, the support layer is configured as a conductive support layer.

[0013] Based on the above technical solution, the conductivity of the film in the thickness direction can be improved, and the deposition and filling of the conductive layer material in the pores can be facilitated, and the conductivity in the thickness direction can be increased to a certain extent.

[0014] Furthermore, the conductive support layer is selected from a carbon-based conductive film, or a polymer conductive film filled with conductive particles.

[0015] Furthermore, the maximum diameter of the pores is 0.01-2 mm.

[0016] Furthermore, the depth of the pores is 5%-100% of the thickness of the support layer.

[0017] Furthermore, the number of pores is set to 1-16 / cm 2 .

[0018] Based on the above technical solution, the strength of the support layer is ensured by controlling the size and number of the pores.

[0019] Furthermore, the diameter of the pores close to the outer side of the film is larger than the diameter of the pores close to the inner side.

[0020] Based on the above technical solution, the filling rate in the hole can be guaranteed, and the conductive layer is more easily attached in the hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 Schematic diagram of the cross-sectional structure of the current collector with the pores and the conductive layer on the same side;

[0023] Figure 2 This is a case where conductive layers and pores are provided on both sides, and the pores on both sides are basically symmetrically arranged;

[0024] Figure 3 This is the case where the conductive layer and pores are set on both sides, and the pores on both sides are staggered and have different depths;

[0025] Figure 4 This is the case where the conductive layer and the aperture are arranged on different sides.

[0026] The horizontal direction represents the lateral direction, and the vertical direction represents the thickness direction.

[0027] In the picture:

[0028] 1-conductive support layer; 11-pores; 2-conductive layer. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the existing technology, since the composite copper current collector is deposited and thickened by water electroplating, the support layer material is generally selected as PET / PP. The surface flatness of the copper conductive layer after electroplating is relatively high. Therefore, during subsequent winding, the air is squeezed out under the action of the winding tension, forming a vacuum compaction. During subsequent unwinding, (partial) delamination is caused due to adhesion of the film roll.

[0032] In order to solve the above technical problems, some embodiments of the present application provide a composite conductive film. Figure 1 , including a support layer having two surfaces; in some embodiments of the present application, the support layer is configured as a conductive support layer 1, which has conductivity and is suitable for water electroplating thickening to form a conductive layer 2 on both sides; the support layer ( Figure 1 A plurality of pores 11 are formed on one surface of the conductive support layer 1, and a conductive layer 2 is formed on the surface of the pore 1 and the surface of the support layer to form a local accommodating cavity, which serves as a space for accommodating air and reduces the vacuum hardening. The support layer is set to a conductive material, which can also promote the growth of the conductive layer on the inner wall of the pore 11 during electroplating, and also improve the overall strength of the film to a certain extent, and also increase the conductivity in the thickness direction to a certain extent.

[0033] Specifically, the support layer has a thickness of 3-100 μm and can be made of a carbon-based conductive film, such as graphite, conductive carbon black, or (oxidized) graphene; or a polymer conductive film filled with conductive particles, such as conductive metals (gold, silver, copper, aluminum, nickel, etc.) or non-metallic materials (such as carbon-based inorganic conductive materials). The filling amount can be adaptively selected, generally ranging from 5% to 30% of the film mass. These conductive support layer materials can also improve the poor thermal conductivity caused by directly using polymers.

[0034] The pores 11 can be formed by needle roller pressing, and the puncture depth is controlled by controlling the distance between the needle roller and the support layer. It can also be formed based on (physical or chemical) etching, such as laser drilling, and the degree of etching is controlled to control the depth and size of the pores. The maximum diameter D of the pores 11 is 0.01-2mm, preferably 0.05-1mm; the pore depth is 5%-100% of the thickness of the support layer, preferably 15%-40%, to avoid excessive pore thickness affecting the tensile strength of the film to a certain extent; at the same time, to ensure space for gas accommodation, the number of pores 11 is preferably set to 1-16 / cm 2, and can be selected in combination with aperture size and depth adaptability.

[0035] In the present application, there is no specific limitation on the shape of the pore 11. Generally, the pore 11 is cylindrical in shape, and the diameter on the outside of the film is preferably larger than the diameter (width) on the inside. This ensures that when the subsequent deposition and thickening of the conductive layer are carried out, the inside has a higher filling rate and the outside ensures larger pores. The sides of the formed holes are inclined and easier to thicken under processes such as evaporation. The high internal filling rate can ensure the strength of the support layer to a certain extent (the conductive layer fills more in the hole).

[0036] In addition, the support layer can be set to a non-conductive material, which can also improve the adhesion of the winding. The conductive layer can be obtained based on evaporation or sputtering. At this time, single-sided or double-sided deposition can be selected to form the conductive layer.

[0037] The conductive layer 2 is made of metal, such as gold, silver, copper, aluminum, nickel, chromium, etc.

[0038] Figure 2-3 FIG shows a case where pores 11 are provided on both surfaces of the conductive support layer 1; in this case, the pores 11 on the two surfaces may have the same arrangement and size (eg Figure 2 ), and may also have asymmetric pore distribution, and / or different pore sizes (including depths) and distributions (e.g. Figure 3 ).

[0039] In addition, if Figure 4 For the case where the conductive layer is set on one side, the pores 11 can be set on the side of the support layer where the conductive layer is not set; similarly, for the case where the conductive layer is set on both sides, pores can be set only on one side or locally corresponding pores (the other side of the support layer corresponding to the pores is not locally provided with pores).

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings or conventionally expressed in the prior art, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0041] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0042] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0043] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A composite conductive film, characterized in that: The invention comprises a supporting layer, a surface of which is provided with a plurality of pores to form a gas accommodating cavity, and a conductive layer is provided on at least one surface of the supporting layer, wherein the conductive layer material partially fills the pores.

2. The composite conductive film according to claim 1, wherein The aperture is provided on at least one side of the support.

3. The composite conductive film according to claim 2, wherein: Differences in pore size and density.

4. The composite conductive film according to claim 1, wherein The supporting layer is configured as a conductive supporting layer.

5. The composite conductive film according to claim 4, wherein: The conductive support layer is selected from a carbon-based conductive film or a conductive film.

6. The composite conductive film according to claim 1, wherein The thickness of the support layer is 3-100 μm.

7. The composite conductive film according to any one of claims 1 to 6, wherein: The maximum diameter of the pores is 0.01-2 mm.

8. The composite conductive film according to any one of claims 1 to 6, wherein: The depth of the pores is 5%-100% of the thickness of the support layer.

9. The composite conductive film according to any one of claims 1 to 6, wherein: The number of pores is set to 1-16 / cm 2 .

10. The composite conductive film according to any one of claims 1 to 6, wherein: The diameter of the pores near the outside of the membrane is larger than the diameter near the inside.

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