A composite metal film

Abstract

The utility model discloses a composite metal film, which includes a substrate, a connecting layer, a catalytic layer, a first metal layer and a conductive part. The substrate includes two first outer surfaces arranged opposite to each other; the connecting layer is connected to the first outer surface and has a second outer surface facing outward; the catalytic layer is connected to the second outer surface and has a third outer surface facing outward. The substrate, the connecting layer and the catalytic layer are integrally provided with a first through hole; the first metal layer is connected to the third outer surface; the conductive part is arranged in the first through hole and connects the two layers of the first metal layer on both sides. The utility model performs perforation on the substrate to open a through hole, and a conductive part connecting the metal layer is arranged in the through hole, so that a composite metal film with double-sided conduction can be obtained, which effectively reduces the impedance of the composite metal film, collects the current generated by the active material of the battery to generate a larger output current, and can produce a high-performance conductive metal film at a lower cost.

Description

Technical Field

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

[0002] Copper foil is a key component of printed circuit boards and lithium-ion batteries, and is a carrier for the assembly of various electronic components. Copper foil is widely used in computers, 5G communications, communication instruments, household appliances, power lithium batteries, energy storage lithium batteries, digital devices and other industries. With the rapid development of the electronic information industry and the new energy industry, the demand for copper foil is also increasing.

[0003] Composite copper foil refers to a new type of material made by evenly plating copper on the surface of a plate by magnetron sputtering, evaporation, ion replacement, etc. Composite copper foil has good tensile strength, elongation, oxidation resistance, corrosion resistance and conductivity, and is widely used in lithium batteries, military shielding films, wireless communications, touch panels, touch conductive films, and energy storage fields and other components that use copper as a conductive carrier.

[0004] Magnetron sputtering is usually used to produce composite copper foil. When the composite copper foil is applied to the battery, the battery is prone to lithium deposition, which reduces the cycle life. The lithium dendrites formed by lithium deposition can easily cause the battery to short-circuit after piercing the diaphragm. At the same time, the copper layer of the composite copper foil produced by magnetron sputtering deposition is poorly uniform and unevenly thick, which increases the impedance of the lithium battery and reduces the battery charging and discharging efficiency. In addition, in the existing technology, the production process of composite copper foil is complex, the production yield is low, the output is low, the investment is large, and it is difficult to mass produce on a large scale.

[0005] To solve the above problems, the application with application publication number CN202410008798.8 proposes a new type of composite copper foil and its preparation method, comprising the following steps: step one: apply a first liquid on the surface of the substrate and then dry it to form a connecting layer; step two: apply a second liquid on the surface of the connecting layer and then dry it to form a catalytic layer; step three: chemically plate the surface of the catalytic layer; step four: electroplate the chemically plated layer; the connecting layer can effectively improve the connection between the substrate and the catalytic layer, the catalytic layer can effectively improve the efficiency of chemical copper plating, and is beneficial to improve the uniformity of the formed first copper film layer, the preparation of the composite copper foil is more efficient and the cost is lower.

[0006] However, the above-mentioned composite copper foil technology has high requirements on the battery cell welding technology. Due to the double-sided composite sandwich structure, the impedance of the conductive copper foil is greatly affected. Lithium battery copper foil acts as the negative electrode current collector of lithium-ion batteries and acts as a carrier of negative electrode active materials. At the same time, it also acts as a negative electrode electron collector and conductor. Its function is to collect the current generated by the battery active materials to generate a larger output current. Therefore, the conductive impedance has a great influence on the performance of the battery cell.

[0007] Therefore, it is necessary to improve the prior art to overcome the above defects in the prior art. Utility Model Content

[0008] The utility model aims to provide a composite metal film, which can reduce the impedance of the composite metal film.

[0009] In order to achieve the above utility model purpose, the utility model proposes a composite metal film, comprising:

[0010] A substrate, comprising two first outer surfaces arranged opposite to each other;

[0011] A connecting layer, the connecting layer is disposed on both of the first outer surfaces, and the connecting layer has a second outer surface facing outwards;

[0012] A catalytic layer, wherein the catalytic layer is disposed on the second outer surfaces of the two connecting layers, and the catalytic layer has a third outer surface facing outward, and a first through hole is disposed on the whole formed by the substrate, the connecting layer and the catalytic layer;

[0013] A first metal layer, the first metal layer being disposed on both of the third outer surfaces; and

[0014] The conductive part is disposed in the first through hole and connects the two first metal layers on both sides.

[0015] Furthermore, the substrate is provided with a plurality of second through holes, and the composite metal film also includes a connecting portion covering the hole wall of the second through hole, the connecting portion is connected to the two connecting layers on both sides of the substrate, the connecting portion is tubular and is provided with a third through hole.

[0016] Furthermore, the composite metal film also includes a catalytic part covering the hole wall of the third through hole, the catalytic part is connected to the two catalytic layers on both sides of the substrate, the catalytic part is tubular, and the conductive part is arranged in the catalytic part.

[0017] Furthermore, the connecting portion and the connecting layer are made of the same material and are integrally formed;

[0018] The catalytic part and the catalytic layer are made of the same material and are integrally formed.

[0019] The conductive part and the first metal layer are made of the same material and are integrally formed.

[0020] Furthermore, the perforation rate of the second through hole on the substrate is 5% to 10%.

[0021] Furthermore, the wall thickness of the connecting part is 0.1-1 um; the wall thickness of the catalytic part is 0.02-0.05 um, and the diameter of the conductive part is 1-10 um;

[0022] The size of the second through hole is 1-10 um.

[0023] Furthermore, the substrate is a transparent substrate, and the thickness of the substrate ranges from 3 to 15 um.

[0024] Furthermore, the connecting layer is prepared by drying a first liquid, wherein the first liquid includes an EVA emulsion, a branched acrylic emulsion, a binder, a defoamer, a dispersant, and a barrier filler;

[0025] The catalytic layer is prepared by drying a second liquid, wherein the second liquid includes a metal ion solution, a reducing agent, a dispersant, a surfactant and deionized water, and the metal ion solution includes one or more ions of palladium, copper, silver, nickel, tin, zinc or gold ions.

[0026] Furthermore, the first liquid comprises, by weight, 10 to 50 parts of EVA emulsion, 10 to 30 parts of branched acrylate emulsion, 1 to 10 parts of barrier filler, 1 to 10 parts of binder, 0.5 to 1 part of defoamer, and 0.1 to 0.5 part of dispersant;

[0027] The solid content of the EVA emulsion is 50% to 60%;

[0028] The branched acrylic emulsion is prepared by adding 0.1 to 10 parts by weight of azobisisobutyronitrile and 3 to 10 parts by weight of a polyether crosslinking agent to a total of 10 to 30 parts by weight of acrylic acid and / or methyl acrylate and / or ethyl acrylate;

[0029] The barrier filler is a surface-modified hetero-nitrogen silicon compound;

[0030] The binder is rosin resin;

[0031] The defoamer is any one of the organosilicon defoamers;

[0032] The dispersant is a BYK series dispersant.

[0033] Furthermore, the second liquid comprises, by weight, 1 to 5 parts of the metal ion solution, 10 to 20 parts of the reducing agent, 0.01 to 0.05 parts of the dispersant, 0.1 to 0.5 parts of the surfactant, and 20 to 80 parts of the deionized water;

[0034] The metal ion solution is a palladium salt, and the palladium salt is a mixture of one or more of palladium sulfate, palladium chloride and palladium acetate;

[0035] The reducing agent is a mixture of one or more of ethyl acetate, ethyl formate and ethylene glycol amine;

[0036] The dispersant is solsperse 44000 or solsperse 46000 or a mixture of the two;

[0037] The surfactant is a fluorosilicone surfactant; or

[0038] The second liquid comprises, by weight, 0.1 to 0.3 parts of the metal ion solution, 5 to 10 parts of the dispersant, 100 to 150 parts of the reducing agent, 1 to 10 parts of the surfactant and 200 to 500 parts of the deionized water;

[0039] The metal ion solution is a silver salt, and the silver salt is silver nitrate or silver perchlorate or a mixture of the two;

[0040] The reducing agent is a mixture of one or more of glucose, hydrazine hydrate, glycerol and triethanolamine;

[0041] The dispersant is polyvinyl pyrrolidone or polyethylene glycol or a mixture of the two;

[0042] The surfactant is Chemours FS-3000 or Chemours FS-3100 or a mixture of the two.

[0043] Further, the material of the first metal layer is one of palladium, copper, silver, nickel, tin, zinc or gold;

[0044] The composite metal film also includes a second metal layer, the thickness of the second metal layer is greater than the thickness of the first metal layer, and the material of the second metal layer is one of palladium, copper, silver, nickel, tin, zinc or gold.

[0045] Compared with the prior art, the utility model has the following beneficial effects: the composite metal film of the utility model connects the two first metal layers on both sides through the conductive part arranged in the first through hole, so as to obtain a composite metal film with double-sided conduction, thereby reducing the impedance of the composite metal film, and collecting the current generated by the active material of the battery to generate a larger output current, so that a high-performance conductive metal film can be produced at a lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a cross-sectional view of a composite metal film in one embodiment of the utility model;

[0047] Figure 2 is a cross-sectional view of a composite metal film in another embodiment of the utility model;

[0048] Figure 3 yes Figure 2 A partial enlarged view of the middle A;

[0049] Figure 4 yes Figure 2 Cross-section of the middle substrate;

[0050] Figure 5 is a cross-sectional view of a composite metal film in another embodiment of the utility model;

[0051] Figure 6 yes Figure 5 A partial enlarged view of point B in the middle;

[0052] Figure 7 is a cross-sectional view of a composite metal film in another embodiment of the utility model;

[0053] Figure 8 yes Figure 7 A partial enlarged view of point C in the middle;

[0054] Fig. 9 yes Figure 7 Cross-section of the middle substrate;

[0055] Fig.10 This is a flow chart of a method for preparing a composite metal film in one embodiment of the utility model;

[0056] Fig.11 It is a flow chart of a method for preparing a composite metal film according to another embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0058] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0059] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] like Figure 1 and Figure 2 As shown, the utility model proposes a composite metal film, comprising: a substrate 1, a connecting layer 2, a catalyst layer 3, a first metal layer 4 and a conductive part 5.

[0061] The substrate 1 includes two first outer surfaces 101 arranged opposite to each other; however, it is understood that the two first outer surfaces 101 are two end surfaces in the thickness direction of the substrate 1 .

[0062] The connection layer 2 is connected to the first outer surface 101 . A connection layer 2 is disposed on each of the two first outer surfaces 101 . The connection layer 2 has a second outer surface 201 facing outward. However, it is understood that facing outward refers to the direction away from the side where the substrate 1 is located.

[0063] The catalytic layer 3 is connected to the second outer surface 201. The second outer surfaces 201 of the upper and lower connecting layers 2 are each provided with a catalytic layer 3. The catalytic layer 3 has a third outer surface 301 facing outward. The substrate 1, the connecting layer 2 and the catalytic layer 3 are integrally provided with a first through hole 6 extending therethrough.

[0064] The first metal layer 4 is connected to the third outer surface 301 , and a first metal layer 4 is disposed on the third outer surfaces 301 of the upper and lower catalyst layers 3 .

[0065] The conductive portion 5 is disposed in the first through hole 6 and connects the two first metal layers 4 on both sides.

[0066] The composite metal film is connected to the two first metal layers 4 on both sides through the conductive part 5 arranged in the first through hole 6, so as to obtain a composite metal film with double-sided conduction, thereby reducing the impedance of the composite metal film, and collecting the current generated by the battery active material to generate a larger output current, so that high-performance conductive metal films, such as conductive copper foil, can be produced at a lower cost.

[0067] In some embodiments, Figure 1 As shown, the substrate 1 , the connecting layer 2 , and the catalytic layer 3 are in direct contact with the conductive part 5 .

[0068] In some embodiments, Figure 2 and Figure 3As shown, the substrate 1 is provided with a plurality of second through holes 7, and the composite metal film further includes a connecting portion 9 covering the hole wall of the second through hole 7, the connecting portion 9 is connected to the two connecting layers 2 on both sides of the substrate 1, and the connecting portion 9 is tubular and is provided with a third through hole 8. Figure 2 and Figure 3 As shown, the composite metal film also includes a catalytic part 10 covering the hole wall of the third through hole 8, the catalytic part 10 is connected to the two catalytic layers 3 on both sides of the substrate 1, the catalytic part 10 is tubular, and the conductive part 5 is arranged in the catalytic part 10, that is, the catalytic part 10 is provided with a first through hole 6, and the conductive part 5 is arranged in the first through hole 6. Preferably, the conductive part 5 fills the first through hole 6 to conduct the two first metal layers 4 on both sides, with good conductivity and lower impedance.

[0069] Figure 2 and Figure 3 In the illustrated embodiment, the connecting portion 9 and the connecting layer 2 are made of the same material and are integrally formed; the catalytic portion 10 and the catalytic layer 3 are made of the same material and are integrally formed; and the conductive portion 5 and the first metal layer 4 are made of the same material and are integrally formed.

[0070] The cross-sectional shape of the second through hole 7 is circular, quadrilateral or polygonal; the cross-sectional shapes of the first through hole 6 and the third through hole 8 correspond to the cross-sectional shape of the second through hole 7. Preferably, Figure 4 As shown, the cross-sectional shape of the second through hole 7 is preferably circular.

[0071] In some embodiments, the perforation rate of the second through hole 7 on the substrate 1 is 5% to 10%, so that the first metal layer 4 on both sides has sufficient conductive parts 5 for conduction, thereby improving the conductive effect and reducing the impedance. The perforation rate refers to the ratio of the total area of ​​the second through hole 7 on the substrate 1 to the surface area of ​​a first outer surface 101 of the substrate 1.

[0072] In some embodiments, the wall thickness W1 of the connecting portion 9 is 0.1-1.0 um; the wall thickness W2 of the catalytic portion 10 is 0.02-0.05 um, and the diameter D2 of the conductive portion 5 is 1-10 um to ensure the conductive effect. Optionally, the diameter D1 of the second through hole 7 is 1-10 um to facilitate the molding of the connecting portion 9 and the catalytic portion 10.

[0073] The substrate 1 is a transparent substrate, and the thickness H of the substrate 1 ranges from 3 to 15 um. In some embodiments, the material of the substrate 1 is a combination of one or more of polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, alicyclic hydrocarbons, polymethyl methacrylate, polyimide, biaxially oriented polypropylene, polypropylene, and polycarbonate, and the substrate 1 made of the above materials has good toughness; in other embodiments, the substrate 1 can be any other transparent material suitable for use as a touch sensor substrate, for example, made of transparent materials such as glass, flexible glass, or quartz, and the material of the substrate 1 can be selected according to the application scenario of the composite metal film.

[0074] The connecting layer 9 is prepared by drying a first liquid, wherein the first liquid includes EVA emulsion, branched acrylate emulsion, adhesive, defoamer, dispersant and barrier filler.

[0075] In some embodiments, the first liquid includes, by weight, 10 to 50 parts of EVA emulsion, 10 to 30 parts of branched acrylate emulsion, 1 to 10 parts of barrier filler, 1 to 10 parts of binder, 0.5 to 1 part of defoamer, and 0.1 to 0.5 parts of dispersant. The barrier filler can improve the adhesion and thickening properties during mixing.

[0076] As an example, the first liquid may include 10 parts of EVA emulsion, 10 parts of branched acrylic emulsion, 1 part of barrier filler, 1 part of binder, 0.5 part of defoamer, and 0.1 part of dispersant; as another example, 50 parts of EVA emulsion, 30 parts of branched acrylic emulsion, 10 parts of barrier filler, 10 parts of binder, 1 part of defoamer, and 0.5 part of dispersant; as yet another example, 25 parts of EVA emulsion, 15 parts of branched acrylic emulsion, 5 parts of barrier filler, 5 parts of binder, 0.7 part of defoamer, and 0.3 part of dispersant.

[0077] Further optionally, the solid content of the above EVA emulsion is 50% to 60% (the solid content is the mass percentage of the remaining part of the emulsion or coating after drying under specified conditions).

[0078] Optionally, the branched acrylic emulsion is prepared by adding 0.1 to 10 parts by weight of azobisisobutyronitrile and 3 to 10 parts by weight of a polyether crosslinking agent to a total of 10 to 30 parts by weight of acrylic acid and / or methyl acrylate and / or ethyl acrylate; the barrier filler is a surface-modified heteroazo silicon compound; the binder is a rosin resin; the defoamer is any one of the silicone defoamers; and the dispersant is a BYK series dispersant.

[0079] The catalytic layer 10 is prepared by drying a second liquid, wherein the second liquid includes a metal ion solution, a reducing agent, a dispersant, a surfactant and deionized water, and the metal ion solution includes one or more ions of palladium, copper, silver, nickel, tin, zinc or gold ions.

[0080] In some embodiments, the metal ion solution is a palladium salt, and the second liquid includes, by weight, 1 to 5 parts of the metal ion solution, 10 to 20 parts of a reducing agent, 0.01 to 0.05 parts of a dispersant, 0.1 to 0.5 parts of a surfactant, and 20 to 80 parts of deionized water.

[0081] As an example, the palladium salt is a mixture of one or more of palladium sulfate, palladium chloride and palladium acetate; the reducing agent is a mixture of one or more of ethyl acetate, ethyl formate and ethylene glycolamine; the dispersant is solsperse 44000 or solsperse 46000 or a mixture of the two; and the surfactant is a fluorosilicone surfactant.

[0082] The above materials are heated and refluxed to prepare an aqueous nano-palladium catalyst solution, in which the particle size of the precious metal nano-palladium is relatively small, ranging from 20 to 400 nm, and has high catalytic activity and stability.

[0083] In other embodiments, the metal ion solution is a silver salt, and the second liquid includes, by weight, 0.1 to 0.3 parts of the metal ion solution, 5 to 10 parts of a dispersant, 100 to 150 parts of a reducing agent, 1 to 10 parts of a surfactant and 200 to 500 parts of deionized water.

[0084] As an example, the silver salt is silver nitrate or silver perchlorate or a mixture of the two; the reducing agent is a mixture of one or more of glucose, hydrazine hydrate, glycerol and triethanolamine; the dispersant is polyvinyl pyrrolidone or polyethylene glycol or a mixture of the two; the surfactant is Chemours FS-3000 or Chemours FS-3100 or a mixture of the two. Preferably, the concentration (wt%) of glucose is 40%.

[0085] The first metal layer 4 is made of one of palladium, copper, silver, nickel, tin, zinc or gold; Figure 5 As shown, the composite metal film also includes a second metal layer 11, the first metal layer 4 has a fourth outer surface 401 facing outward, and the second metal layer 11 is arranged on the fourth outer surface 401 of the first metal layer 4. Optionally, the thickness of the second metal layer 11 is greater than the thickness of the first metal layer 4. Preferably, the first metal layer 4 is made by chemical copper plating, and the second metal layer 11 is made by electroplating, which is used to thicken the metal layer of the composite metal film. It can be understood that when the material of the first metal layer 4 and the second metal layer 11 is copper, the composite metal film is a composite copper foil.

[0086] When the first liquid is coated on the surface of the substrate 1 provided with the second through hole 7, part of the first liquid can enter the second through hole 7 and adhere to the hole wall of the second through hole 7. The part of the first liquid located on the surface of the substrate 1 forms the connection layer 2, and the part located in the second through hole 7 forms the connection part 9. When forming the connection part 9, the third through hole 8 can be directly formed by process control, or the third through hole 8 can be formed by subsequent processing.

[0087] Similarly, when the second liquid is applied, part of the second liquid can enter the third through hole 8 and adhere to the hole wall of the third through hole 8. The part of the second liquid located on the surface of the substrate 1 forms the catalyst layer 3, and the part located in the third through hole 8 forms the catalyst part 10. When forming the catalyst part 10, the first through hole 6 can be directly formed by process control, or the first through hole 6 can be formed by subsequent processing.

[0088] When chemical copper plating is performed, metal material will be deposited on the surface of the catalyst layer 3 and the catalyst part 10 to form the first metal layer 4 and the conductive part 5. In some embodiments, Figure 5 and Figure 6 As shown, the formed conductive portion 5 directly fills the sixth through hole 6, and during subsequent electroplating, the second metal layer 11 is only formed on the outer surface of the first metal layer 4. In other embodiments, such as Figures 7 to 9 As shown, the conductive part 5 includes a first conductive part 501 and a second conductive part 502. The first conductive part 501 and the first metal layer 4 are made of the same material and are integrally formed. The second conductive part 502 and the second metal layer 11 are made of the same material and are integrally formed. When chemical copper plating is performed, the conductive part formed on the surface of the catalyst part 10 does not fill up the first through hole 6, that is, a tubular first conductive part 501 is first formed, which is provided with a fourth through hole 12. When electroplating is performed later, metal material is deposited inside the first conductive part 501 to form the second conductive part 502. The first conductive part 501 and the second conductive part 502 cooperate to fill up the first through hole 6; the second conductive part 502 is simultaneously connected to the two second metal layers 11 on both sides.

[0089] like Fig.10 As shown, the utility model proposes a method for preparing a composite metal film, comprising the following steps:

[0090] S1, providing a substrate 1;

[0091] S2, opening a plurality of second through holes 7 on the substrate 1;

[0092] S3, coating the first liquid on the substrate 1 with the second through hole 7, so that the two first outer surfaces 101 of the substrate 1 and the hole wall of the second through hole 7 are covered with the first liquid, drying the first liquid, the first liquid on the two first outer surfaces 101 is dried to form a connecting layer 2, and the second liquid on the hole wall of the second through hole 7 is dried to form a connecting portion 9, and the connecting portion 9 has a third through hole 8;

[0093] S4, coating the second liquid on the second outer surface 201 of the connecting layer 2 and the hole wall of the third through hole 8, drying the second liquid, drying the second liquid on the second outer surface 201 to form the catalytic layer 3, and drying the second liquid on the hole wall of the third through hole 8 to form the catalytic part 10, the catalytic part 10 having the first through hole 6 penetrating the whole body composed of the substrate 1, the connecting layer 2 and the catalytic layer 3;

[0094] S5 , performing chemical copper plating on the semi-finished product obtained in step S4 , forming a first metal layer 4 on the third outer surface 301 of the catalyst layer 3 , and forming a conductive portion 5 on the inner wall of the first through hole 6 .

[0095] As a preferred embodiment, Fig.11 As shown, the method for preparing the composite metal film also includes the following steps:

[0096] S6 , electroplating the product obtained in step S5 to form a second metal layer 11 outside the first metal layer 4 .

[0097] In the above step S2, the second through hole 7 may be formed on the substrate 1 by, for example, circular knife stamping, laser cutting, metal ion bombardment, or other perforation methods.

[0098] In the above step S3, when forming the connection part 9, the third through hole 8 can be formed naturally by process control, or the connection part 9 can be filled with the second through hole 7 first, and then the third through hole 8 can be formed by processing. The method of processing the through hole can be, for example, a circular knife stamping method, a laser cutting method, a metal ion bombardment method, or other perforation methods.

[0099] In the above step S4, when the catalyst part 10 is formed, the first through hole 6 can be formed naturally by process control, or the catalyst part 10 can be filled with the first through hole 6 first, and then the first through hole 6 is formed by processing. The through hole processing method can be, for example, a circular knife stamping method, a laser cutting method, a metal ion bombardment method, or other perforation methods.

[0100] The above-mentioned composite metal film is formed by opening a through hole on the substrate 1, and then coating and drying the substrate 1 with the through hole to form a connecting layer 2 and a connecting portion 9, and by coating and drying to form a catalytic layer 3 and a catalytic portion 10, and then forming a first metal layer 4 by chemical copper plating, and forming a second metal layer 11 by electroplating a thickened metal layer. The connecting layer 2 can effectively improve the connection force between the catalytic layer 3, and the catalytic layer 3 can effectively improve the efficiency of chemical copper plating, and is conducive to improving the uniformity of the formed first metal layer 4 and the second metal layer 11. The obtained metal layer is more uniform than the metal layer obtained by magnetron sputtering. Moreover, the entire preparation method does not need to use magnetron sputtering, evaporation and other methods, and can efficiently prepare composite metal films, with lower costs, and is not prone to problems such as roller breaking caused by substrate perforation. When it is applied to lithium batteries, it can effectively reduce the risk of lithium precipitation, thereby improving the service life and reliability of the battery.

[0101] Furthermore, the metal layers on both sides of the composite metal film are connected through the conductive part, which can effectively reduce the overall impedance and collect the current generated by the battery active material to generate a larger output current.

[0102] The above are only specific implementations of the present invention, and any improvements made based on the concept of the present invention are considered to be within the protection scope of the present invention.

Claims

1. A composite metal film, characterized in that: include: A substrate, comprising two first outer surfaces arranged opposite to each other; A connecting layer, the connecting layer is disposed on both of the first outer surfaces, and the connecting layer has a second outer surface facing outwards; A catalytic layer, wherein the catalytic layer is disposed on the second outer surfaces of the two connecting layers, and the catalytic layer has a third outer surface facing outward, and a first through hole is disposed on the whole formed by the substrate, the connecting layer and the catalytic layer; A first metal layer, the first metal layer being disposed on both of the third outer surfaces; and The conductive part is disposed in the first through hole and connects the two first metal layers on both sides.

2. The composite metal film according to claim 1, characterized in that The substrate is provided with a plurality of second through holes, and the composite metal film further comprises a connecting portion covering the hole wall of the second through hole, the connecting portion is connected to the two connecting layers on both sides of the substrate, the connecting portion is tubular and is provided with a third through hole.

3. The composite metal film according to claim 2, characterized in that: The composite metal film also includes a catalytic part covering the hole wall of the third through hole, the catalytic part is connected to the two catalytic layers on both sides of the substrate, the catalytic part is tubular, and the conductive part is arranged in the catalytic part.

4. The composite metal film according to claim 3, characterized in that: The connecting portion and the connecting layer are made of the same material and are integrally formed; The catalytic part and the catalytic layer are made of the same material and are integrally formed; The conductive part and the first metal layer are made of the same material and are integrally formed.

5. The composite metal film according to claim 2, characterized in that: The perforation rate of the second through hole on the substrate is 5% to 10%.

6. The composite metal film according to claim 3, characterized in that: The wall thickness of the connecting part is 0.1-1um; the wall thickness of the catalytic part is 0.02-0.05um; and the diameter of the conductive part is 1-10um; The size of the second through hole is 1-10 um.

7. The composite metal film according to claim 1, characterized in that: The substrate is a transparent substrate, and the thickness of the substrate is in the range of 3 to 15 um.

8. The composite metal film according to any one of claims 1 to 7, characterized in that: The material of the first metal layer is one of palladium, copper, silver, nickel, tin, zinc or gold; The composite metal film also includes a second metal layer, the thickness of the second metal layer is greater than that of the first metal layer, and the material of the second metal layer is one of palladium, copper, silver, nickel, tin, zinc or gold.

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