Composite conductive film

Abstract

The invention provides a composite conductive film which comprises a flexible supporting layer, a first metal layer and a second metal layer are arranged on the flexible supporting layer, the first metal layer comprises a metal material with the crystal face being 111, and the second metal layer comprises a metal material with the crystal face being 111. According to the scheme, the first metal layer and the second metal layer are arranged on the flexible supporting layer, the first metal comprises the metal material with the crystal face of 111, and the metal material with the crystal face of 111 is relatively high in atomic density, so that the surface of the flexible supporting layer can be completely covered; therefore, the material of the second metal layer can be formed on the first metal layer, and the material of the second metal layer is prevented from burning through the flexible supporting layer. The second metal layer comprises the metal material with the crystal face of 111, and the surface energy of the metal material with the crystal face of 111 is extremely low, so that the oxidation resistance of the second metal layer is high, and the oxidation resistance of the composite conductive film is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a composite conductive film. Background Art

[0002] The composite conductive film is both flexible and conductive. It is flexible because the flexible film material is used as the substrate, and it is conductive because the conductive material is formed on the flexible film material. However, the existing composite conductive film has weak antioxidant ability. Therefore, the existing technology still needs to be improved. Summary of the Invention

[0003] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a composite conductive film to solve the problem of weak antioxidant ability of the existing composite conductive film in the background art.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A composite conductive film, characterized in that it includes a flexible support layer, a first metal layer and a second metal layer are provided on the flexible support layer, the first metal includes a metal material with a crystal plane of 111, and the second metal layer includes a metal material with a crystal plane of 111.

[0005] Through the above solution, since the first metal layer and the second metal layer are provided on the flexible support layer, and the first metal includes a metal material with a crystal plane of 111, because the atomic density of the metal material with a crystal plane of 111 is relatively high, it can completely cover the surface of the flexible support layer, which helps the material of the second metal layer to be formed on the first metal layer and prevents the material of the second metal layer from burning through the flexible support layer. Moreover, the second metal layer includes a metal material with a crystal plane of 111. Since the surface energy of the metal material with a crystal plane of 111 is extremely low, the antioxidant property of the second metal layer is strong, improving the antioxidant performance of the composite conductive film of the present invention.

[0006] In the present invention, the second metal layer further includes a metal material with a crystal plane of 200.

[0007] In the present invention, in the first metal layer, a metal material with a crystal plane of 220 is further included, and the content of the metal material with a crystal plane of 111 in the first metal layer is greater than the content of the metal material with a crystal plane of 220 in the first metal layer.

[0008] In the present invention, in the first metal layer, a metal material with a crystal plane of 311 is further included, and the content of the metal material with a crystal plane of 111 in the first metal layer is greater than the content of the metal material with a crystal plane of 311.

[0009] In the present invention, in the first metal layer, there is also a metal material with a crystal plane of 200, and the content of the metal material with a crystal plane of 200 in the first metal layer is greater than that of the metal material with a crystal plane of 220.

[0010] In the present invention, the content of the metal material with a crystal plane of 200 in the first metal layer is greater than that of the metal material with a crystal plane of 311.

[0011] In the present invention, in the second metal layer, from the inside of the flexible support layer towards both sides in the width direction, the content of the metal material with a crystal plane of 111 increases.

[0012] In the present invention, in the first metal layer, from both sides of the flexible support layer towards the inside, the content of the metal material with a crystal plane of 111 increases, and the content of the metal material with a crystal plane of 220 decreases.

[0013] In the present invention, in the second metal layer, from the inside of the flexible support layer towards both edges in the width direction of the flexible support layer, the content of the metal material with a crystal plane of 200 increases.

[0014] Compared with the prior art, the present invention provides a composite conductive film. Since a first metal layer and a second metal layer are provided on the flexible support layer, the first metal contains a metal material with a crystal plane of 111. Because the atomic density of the metal material with a crystal plane of 111 is relatively high, it can completely cover the surface of the flexible support layer, thereby helping the material of the second metal layer to form on the first metal layer and preventing the material of the second metal layer from burning through the flexible support layer. Moreover, the second metal layer contains a metal material with a crystal plane of 111. Because the surface energy of the metal material with a crystal plane of 111 is extremely low, the oxidation resistance of the second metal layer is strong, improving the oxidation resistance of the composite conductive film of the present invention. Description of the Drawings

[0015] Figure 1 It is a structural diagram of a composite conductive film provided by the present invention.

[0016] In the figure: 1. Flexible support layer, 2. First metal layer, 3. Second metal layer. Detailed Embodiments

[0017] To make the purpose, technical solutions and effects of the present invention clearer and more definite, the following further describes the present invention in detail with reference to the accompanying drawings and by way of examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] It should be noted that when a component is said to be "mounted on", "fixed to" or "disposed on" another component, it can be directly on the other component or there may be an intermediate component at the same time. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time.

[0019] It should also be noted that the orientation terms such as left, right, up, and down in the embodiments of the present invention are only relative concepts to each other or are referenced based on the normal use state of the product, and should not be considered restrictive.

[0020] The function of the composite conductive film is to conduct electricity, that is, to allow current to pass through the surface of the conductive film. Its conductive function mainly comes from the metal layer of the current collector. However, the current composite conductive film has weak antioxidant ability, resulting in oxidation problems during the production and transportation of the composite conductive film, damaging the conductive ability of the composite conductive film. Therefore, as Figure 1As shown, the inventor proposes a composite conductive film. The composite conductive film includes a flexible support layer 1, on which a first metal layer 2 and a second metal layer 3 are provided. The first metal 2 comprises a metal material with a crystal plane of 111, and the second metal layer 3 comprises a metal material with a crystal plane of 111. Thus, since the first metal layer 2 and the second metal layer 3 are provided on the flexible support layer, and the first metal 2 comprises a metal material with a crystal plane of 111, and since the atomic density of the metal material with a crystal plane of 111 is relatively high, it can completely cover the surface of the flexible support layer, which helps the material of the second metal layer 3 to form on the first metal layer 2 and prevents the material of the second metal layer 3 from burning through the flexible support layer 1. Moreover, the second metal layer 3 comprises a metal material with a crystal plane of 111. Since the surface energy of the metal material with a crystal plane of 111 is extremely low, the second metal layer 3 has strong oxidation resistance, improving the oxidation resistance of the composite conductive film of the present invention. Preferably, the thickness of the first metal layer 2 is less than the thickness of the second metal layer 3, which can reduce the thickness of the first metal layer 2 and prevent the flexible support layer from being burned through. Preferably, the thermal conductivity of the first metal layer 2 is greater than the thermal conductivity of the flexible support layer 1. Thus, when the first metal 2 layer is formed on the flexible support layer, the heat brought by the material of the first metal layer 2 will be quickly transferred to the flexible support layer 1, and the cooling main drum in contact with the flexible support layer 1 can quickly absorb the heat, preventing the heat from affecting the flexible support layer 1. Specifically, the thermal conductivity of the first metal layer 2 is 200 - 250 W / (m·K). The thickness of the first metal layer 2 is less than the thickness of the second metal layer 3, and the thermal conductivity of the first metal layer 2 is greater than the thermal conductivity of the flexible support layer 1. Since the thickness of the first metal layer 2 is relatively low, the heat carried by the first metal layer 2 is less, and the thermal conductivity of the first metal 2 layer is greater than the thermal conductivity of the flexible support layer 1. Thus, the heat carried by the first metal layer 2 can be more quickly conducted out, thereby preventing the flexible support layer 1 from being burned through and reducing the occurrence of pinholes.

[0021] Furthermore, in the present invention, in the first metal layer 2, there is also a metal material with a crystal plane of 220. The content of the metal material with a crystal plane of 111 in the first metal layer 2 is greater than that of the metal material with a crystal plane of 220 in the first metal layer 2. Since the metal material with a crystal plane of 220 can significantly slow down the penetration of the corrosive medium, adding the metal material with a crystal plane of 220 to the first metal layer 2 can prevent external oxidizing substances from passing through the second metal layer 3 and entering the first metal layer 2, and then contacting the flexible support layer 1. In this way, the metal material with a crystal plane of 220 in the first metal layer 2 acts as the final protective shield and can also prevent the occurrence of pinholes in the flexible support layer 1. Preferably, in the first metal layer 2 at the width edge position of the flexible support layer 1, the content of the metal material with a crystal plane of 220 is greater than that of the metal material with a crystal plane of 111. In this way, when the flexible composite conductive film of the present invention is applied to a battery, the electrolyte enters from the edge of the flexible composite conductive film and corrodes the flexible composite conductive film and the second metal layer 3. Preferably, the edge position of the flexible composite conductive film refers to a distance of 0 cm - 10 cm from the edge of the flexible composite conductive film, that is, in this region, the content of the metal material with a crystal plane of 220 is greater than that of the metal material with a crystal plane of 111. Specifically, in this region, the content of the metal material with a crystal plane of 220 is 60% - 80% of the mass of the first metal layer 2 in this region.

[0022] Furthermore, in the composite conductive film of the present invention, the material of the flexible support layer 1 can be one or more of polyoxymethylene, polyethylene, polyvinyl methyl ether, polyvinyl ethyl ether, ethylene - propylene copolymer, polyvinyl alcohol, polyvinyl acetate, polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyacrylic acid, polymethyl methacrylate, polyethyl acrylate, poly(butyl α - cyanoacrylate), polyacrylonitrile, polyisobutylene rubber, chloroprene rubber, natural rubber, gutta - percha rubber, styrene - butadiene rubber, polydecamethylene formamide, polyhexamethylene adipamide, polydecamethylene adipamide, polyethylene terephthalate, polyethylene oxide, polyphenylene sulfide, poly[bis(trifluoroethoxy)phosphazene], polydimethylsiloxane, biaxially oriented polypropylene film. The thickness of the support layer is 3 μm - 12 μm. In the present invention, the metal materials with crystal planes of 111 and 220 can be the same or different. Preferably, the metal materials with crystal planes of 111 and 220 are aluminum, copper, silver, gold, nickel, platinum, lead, etc.

[0023] Furthermore, in the present invention, in the first metal layer 2, there is also a metal material with a crystal plane of 311, and the content of the metal material with a crystal plane of 111 in the first metal layer 2 is greater than that of the metal material with a crystal plane of 311. The crystal structure with a crystal plane index of 311 is a rhombic prism plane and is sensitive to defects. If the metal material with a crystal plane of 311 exists, it may indicate the presence of impurity phases or an increase in defect density in the sample. That is, the metal material with a crystal plane of 311 acts as a probe and can prevent defects in the composite conductive film. In the present invention, the metal material with a crystal plane of 311 can be aluminum, copper, silver, gold, nickel, platinum, lead, etc.

[0024] Furthermore, in the second metal layer, there is also a metal material with a crystal plane of 311, and the content of the metal material with a crystal plane of 311 in the second metal layer is less than that of the metal material with a crystal plane of 111. In this way, since the metal material with a crystal plane of 311 has a probing effect, it is convenient for subsequent detection. And the content of the metal material with a crystal plane of 311 in the second metal layer being less than that of the metal material with a crystal plane of 111 can reduce the weight. Thus, in this embodiment, a method for preparing the composite conductive film can also be provided, including the following steps: Step S1, forming a first metal layer on the flexible support layer by vacuum evaporation; Step S2, forming a second metal layer containing a metal material with a crystal plane of 311 on the first metal layer; Step S3, detecting the composite conductive film formed with the metal material with a crystal plane of 311 by XRD.

[0025] Furthermore, in the present invention, in the second metal layer 3, there is also a metal material with a crystal plane of 200. Since the microstructure of the metal material with a crystal plane of 200 is a square plane with four atoms arranged on each face, that is, the atoms of the metal material with a crystal plane of 200 are arranged relatively sparsely. In this way, it is beneficial to form other materials on the second metal layer 3. For example, an active material layer can be formed on the second metal layer 3. In this way, the active material layer will contact the first metal layer 2 and the second metal layer 3, thereby improving the bonding force between the active material layer and the second metal layer 3 and the first metal layer 2. Moreover, the relatively sparse metal material with a crystal plane of 200 makes the quality of the second metal layer 3 lower, thereby reducing the weight and cost of the composite conductive film. In the present invention, the metal material with a crystal plane of 200 can be aluminum, copper, silver, gold, nickel, platinum, lead, etc.

[0026] Furthermore, in the composite conductive film of the present invention, in the present invention, the content of the metal material with the crystal plane of 200 in the first metal layer 2 is greater than that of the metal material with the crystal plane of 311. Due to the existence of the metal material with the crystal plane of 200, and the atomic arrangement of the metal material with the crystal plane of 200 being more loose, the 311 material can also be embedded between the atoms of the loose metal material with the crystal plane of 200, and a large amount of the metal material with the crystal plane of 111 will be formed on the metal material with the crystal plane of 200 and the metal material with the crystal plane of 311, enabling the metal material with the crystal plane of 311 to better play the role of a probe. Thus, the present invention also provides a method for producing the composite conductive film, including first forming the metal material with the crystal plane of 200 on the flexible support layer, then forming the metal material with the crystal plane of 311 on the metal material with the crystal plane of 200, and finally forming the metal material with the crystal plane of 111 on the metal material with the crystal plane of 311. In this way, the metal material with the crystal plane of 200, the metal material with the crystal plane of 311, and the metal material with the crystal plane of 111 on the obtained composite conductive film are not easily detached from the flexible support layer, and it is convenient to monitor whether there are defects in the composite conductive film. Preferably, after forming the metal material with the crystal plane of 111 on the metal material with the crystal plane of 311, XRD can be used to detect the composite conductive film to check whether there are defects in the composite conductive film obtained after forming the metal material with the crystal plane of 111 on the metal material with the crystal plane of 311. Preferably, after detecting the composite conductive film by XRD, a layer of the metal material with the crystal plane of 111 can be further formed on the metal material with the crystal plane of 111. Preferably, the metal material with the crystal plane of 111, the metal material with the crystal plane of 311, and the metal material with the crystal plane of 200 are formed on the flexible support layer by vacuum evaporation. Preferably, the total thickness of the metal material with the crystal plane of 111, the metal material with the crystal plane of 200, and the metal material with the crystal plane of 311 is 10nm - 200nm. Preferably, the material of the metal material with the crystal plane of 311 is different from the materials of the metal material with the crystal plane of 111 and the metal material with the crystal plane of 200. In this way, the material of the metal material with the crystal plane of 311 as a doped metal can endow the composite conductive film with better tensile strength and puncture resistance.Preferably, the metal material with the crystal plane of 311 is preferably a metal with strong flexibility. In this way, after the metal material with the crystal plane of 311, the metal material with the crystal plane of 200, and the metal material with the crystal plane of 111 are formed on the flexible support layer, during the roller transportation process in vacuum evaporation, the metal material with the crystal plane of 311 has good flexibility. Under pressure conditions, the metal material with the crystal plane of 311 fills the gaps between the atoms of the metal material with the crystal plane of 200, which can make the density of the metal material with the crystal plane of 311, the metal material with the crystal plane of 200, and the metal material with the crystal plane of 111 higher. When the composite conductive film of the present invention is used in a battery, the electrolyte cannot penetrate the high-density protective wall composed of the metal material with the crystal plane of 311, the metal material with the crystal plane of 200, and the metal material with the crystal plane of 111. Therefore, the service life of the flexible support layer can be improved. Preferably, in the high-density protective wall composed of the metal material with the crystal plane of 311, the metal material with the crystal plane of 200, and the metal material with the crystal plane of 111, the mass ratio of the metal material with the crystal plane of 111 is 70%-80%, the mass ratio of the metal material with the crystal plane of 311 is 5%-10%, and the mass ratio of the metal material with the crystal plane of 200 is 10%-30%.

[0027] Further, in the composite conductive film of the present invention, the content of the metal material with a crystal plane of 200 in the first metal layer 2 is greater than that of the metal material with a crystal plane of 220. Since the atomic density of the crystal plane of the metal material with a crystal plane of 220 is about 50%-70% of that of the metal material with a crystal plane of 110, compared with the metal material with a crystal plane of 110, the surface energy of the metal material with a crystal plane of 220 is higher and the chemical activity is stronger. Thus, when the content of the metal material with a crystal plane of 200 in the first metal layer 2 is greater than that of the metal material with a crystal plane of 220, the metal material with a crystal plane of 200 will be formed between the atoms of the metal material with a crystal plane of 220, and then the metal material with a crystal plane of 110 will be formed between the metal material with a crystal plane of 220 and the metal material with a crystal plane of 200. Thus, due to the presence of the metal material with a crystal plane of 220, when external oxidants enter the interior of the composite conductive film, the metal material with a crystal plane of 220 will be preferentially oxidized, preventing the metal materials with crystal planes of 110 and 200 from being oxidized. If the metal material with a crystal plane of 200 is oxidized, the bonding force between the metal material with a crystal plane of 200 and the flexible support layer will become lower. Due to the presence of the metal material with a crystal plane of 110 with a higher atomic density, it can block the entry of external oxidants. Even if oxidants enter, due to the presence of the metal material with a crystal plane of 220, the oxidants will preferentially oxidize the metal material with a crystal plane of 220. Since the content of the metal material with a crystal plane of 200 in the first metal layer 2 is greater than that of the metal material with a crystal plane of 220, the metal material with a crystal plane of 200 can be well protected with a small amount of the metal material with a crystal plane of 220, which can reduce costs and weight while improving the bonding force.

[0028] Further, in the composite conductive film of the present invention, in the second metal layer 3, from the inside of the flexible support layer to both sides in the width direction, the content of the metal material with a crystal plane of 111 increases. Since the atomic density between the atoms of the metal material with a crystal plane of 111 is large, and when the composite conductive film of the present invention is used in a battery, metal sheets will be welded at the edge positions of the flexible conductive film, and the current will converge from the composite conductive film to the edge positions of the flexible conductive film and then flow out through the metal sheets. During welding, if the atomic density between the atoms of the metal material with a crystal plane of 111 is large, then during welding, a mixture of the molten flexible support layer and the metal material with a crystal plane of 111 will appear at the welded part of the composite conductive film. If the content of the metal material with a crystal plane of 111 is high, the formed mixture has stronger conductivity, making the battery less likely to heat up. Also, from the inside of the flexible support layer to both sides in the width direction, the content of the metal material with a crystal plane of 111 increases, which can also prevent the electrolyte in the battery from entering the interior of the composite conductive film from the edge of the composite conductive film, effectively improving the service life of the flexible conductive film.

[0029] In the present invention, in the first metal layer 2, from both sides of the flexible support layer inward, the content of the metal material with the crystal plane of 111 increases, and the content of the metal material with the crystal plane of 220 decreases. Since the content of the metal material with the crystal plane of 111 decreases at the edge of the first metal layer 2, but the content of the metal material with the crystal plane of 220 decreases, the metal material with the crystal plane of 220 can prevent external oxidizing substances from entering at the edge position of the first metal layer 2. At the same time, due to the presence of the metal material with the crystal plane of 220 and in the second metal layer 3, from the inside of the flexible support layer to both sides in the width direction, the content of the metal material with the crystal plane of 111 increases, which can avoid the problem of poor conductivity at the welding part when the composite conductive film is welded.

[0030] In the present invention, in the second metal layer 3, from the inner side of the flexible support layer 1 to both side edges in the width direction of the flexible support layer 1, the content of the metal material with the crystal plane of 200 increases. Since the microstructure of the metal material with the crystal plane of 200 is a square plane, and there are four atoms arranged on each surface, that is, the arrangement of atoms in the metal material with the crystal plane of 200 is relatively sparse. By adopting the method of increasing the content of the metal material with the crystal plane of 200 from the inner side of the flexible support layer to both side edges in the width direction of the flexible support layer, and adding that in the second metal layer 3, from the inside of the flexible support layer to both sides in the width direction, the content of the metal material with the crystal plane of 111 increases, the bonding force between the metal material with the crystal plane of 200 and the metal material with the crystal plane of 111 can be improved, and the shedding of the active material can be prevented after the active material is coated on the second metal layer 3.

[0031] In summary, a composite conductive film is characterized in that it includes a flexible support layer 1, a first metal layer 2 and a second metal layer 3 are provided on the flexible support layer 1. The first metal 2 contains a metal material with the crystal plane of 111, and the second metal layer 3 contains a metal material with the crystal plane of 111. Since the first metal layer 2 and the second metal layer 3 are provided on the flexible support layer, and the first metal 2 contains a metal material with the crystal plane of 111, and since the atomic density of the metal material with the crystal plane of 111 is relatively high, it can completely cover the surface of the flexible support layer 1, which helps the material of the second metal layer 3 to form on the first metal layer 2 and prevents the material of the second metal layer 3 from burning through the flexible support layer 1. Moreover, the second metal layer 3 contains a metal material with the crystal plane of 111. Since the surface energy of the metal material with the crystal plane of 111 is extremely low, the oxidation resistance of the second metal layer 3 is strong, and the oxidation resistance of the composite conductive film of the present invention is improved.

[0032] It is understandable that those of ordinary skill in the art can make equivalent substitutions or modifications based on the technical solution of the present invention and its inventive concept, and all such changes or substitutions should fall within the protection scope of the claims appended to the present invention.

Claims

1. A composite conductive film, characterized in that, It includes a flexible support layer, on which a first metal layer and a second metal layer are provided. The first metal comprises a metal material with a crystal plane of 111, and the second metal layer comprises a metal material with a crystal plane of 111.

2. The composite conductive film according to claim 1, wherein The second metal layer further includes a metal material with a crystal plane of 200.

3. The composite conductive film according to claim 2, wherein, In the first metal layer, there is also a metal material with a crystal plane of 220, and the content of the metal material with a crystal plane of 111 in the first metal layer is greater than the content of the metal material with a crystal plane of 220 in the first metal layer.

4. The composite conductive film according to claim 3, characterized in that, In the first metal layer, there is also a metal material with a crystal plane of 311, and the content of the metal material with a crystal plane of 111 in the first metal layer is greater than the content of the metal material with a crystal plane of 311.

5. The composite conductive film according to claim 4, characterized in that, In the second metal layer, there is also a metal material with a crystal plane of 311, and the content of the metal material with a crystal plane of 311 in the second metal layer is less than the content of the metal material with a crystal plane of 111.

6. The composite conductive film according to claim 5, characterized in that, The content of the metal material with a crystal plane of 200 in the first metal layer is greater than the content of the metal material with a crystal plane of 220.

7. The composite conductive film according to claim 6, wherein, The content of the metal material with a crystal plane of 200 in the first metal layer is greater than the content of the metal material with a crystal plane of 311.

8. The composite conductive film according to claim 1, characterized in that, In the second metal layer, from the inside of the flexible support layer towards both sides in the width direction, the content of the metal material with a crystal plane of 111 increases.

9. The composite conductive film according to claim 8, characterized in that, In the first metal layer, from both sides of the flexible support layer towards the inside, the content of the metal material with a crystal plane of 111 increases, and the content of the metal material with a crystal plane of 220 decreases.

10. The composite conductive film according to claim 8, wherein In the second metal layer, from the inner side of the flexible support layer towards the two edge directions in the width direction of the flexible support layer, the content of the metal material with a crystal plane of 200 increases.

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