Current collector, preparation method thereof and battery

Abstract

The invention belongs to the technical field of batteries. The invention discloses a current collector. The current collector comprises a first metal layer, a first deposition layer, a base material layer, a second deposition layer, a second metal layer and a deposition conductor, the first deposition layer is arranged on one side of the first metal layer; the base material layer is arranged on the side, away from the first metal layer, of the first deposition layer, a through hole is formed in the base material layer, and the ratio of the aperture of the through hole to the thickness of the base material layer is 1: (8-60); the second deposition layer is arranged on the side, away from the first deposition layer, of the base material layer; the second metal layer is arranged on the side, away from the base material layer, of the second deposition layer; the deposition conductor is located in at least part of the through hole of the base material layer, one end of the deposition conductor is connected to the first deposition layer, and the other end of the deposition conductor is connected to the second deposition layer. The invention also discloses a battery. The current-collecting upper surface and the current-collecting lower surface are more balanced in electrical property, low in resistivity, good in conductive effect and high in energy utilization rate.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a current collector, a preparation method thereof, and a battery. Background Art

[0002] A composite current collector usually includes a substrate layer of polymer material and metal layers on both sides of the substrate layer. The substrate layer of polymer material, as the main component of the current collector, can reduce the use of pure metal foil, improve the mechanical properties of the current collector such as tensile strength and elongation at break, reduce the total mass of the current collector, and thereby improve the energy density of the battery.

[0003] However, in the process of implementing the technical solution in the embodiments of the present application, the applicant found that the above technology has at least the following technical problems:

[0004] The overall conductivity of the composite current collector is still not as good as that of pure metal current collectors such as traditional copper foil and aluminum foil, resulting in high energy loss and poor heat transfer effect of the composite current collector. In addition, the current collector needs to be provided with tabs or metal layers on both sides to form a passage between the upper and lower surfaces, which is complex in process and has low reliability. Summary of the invention

[0005] The embodiment of the present application provides a current collector with lower resistivity, lower energy loss and higher conductive efficiency.

[0006] An embodiment of the present application provides a current collector, which includes a first metal layer, a first deposition layer, a substrate layer, a second deposition layer, a second metal layer and a deposition conductor; the first deposition layer is arranged on one side of the first metal layer; the substrate layer is arranged on a side of the first deposition layer away from the first metal layer, and a through hole is arranged on the substrate layer, and the ratio of the aperture of the through hole to the thickness of the substrate layer is 1:(8-60); the second deposition layer is arranged on a side of the substrate layer away from the first deposition layer; the second metal layer is arranged on a side of the second deposition layer away from the substrate layer; the deposition conductor is located in at least part of the through hole of the substrate layer, one end of the deposition conductor is connected to the first deposition layer, and the other end of the deposition conductor is connected to the second deposition layer.

[0007] Furthermore, the current collector further includes a dielectric layer, and the dielectric layer is disposed at least one of between the substrate layer and the first deposition layer or between the substrate layer and the second deposition layer.

[0008] Furthermore, the hole density of the through holes in the substrate layer is 1.1×10 7 -1.6×10 8 Pieces / cm 2 , the porosity of the substrate layer is 3%-20%.

[0009] Furthermore, the ratio of the aperture of the through hole to the thickness of the first metal layer is 1:(2-12).

[0010] Furthermore, the diameter of the through hole is 100-500 nm.

[0011] Furthermore, the substrate layer includes a nuclear pore membrane; in parts by weight, the preparation materials of the nuclear pore membrane include 1000 parts by weight of a main resin, 10-36 parts by weight of modified graphene oxide, 5-18 parts by weight of a coupling agent and 1-6 parts by weight of an inorganic filler.

[0012] Furthermore, the nuclear pore membrane comprises a core layer and a surface layer, the surface layer is arranged on at least one side of the core layer, and the mass ratio of the core layer to the surface layer is (80-90):(10-20);

[0013] Furthermore, in parts by weight, the preparation materials of the core layer include 1000 parts by weight of a main resin, 15-35 parts by weight of modified graphene oxide, 7.5-17 parts by weight of a coupling agent and 2-4 parts by weight of an inorganic filler; the preparation materials of the surface layer include 1000 parts by weight of a main resin, 10-18 parts by weight of modified graphene oxide, 5-12 parts by weight of a coupling agent and 0.1-0.6 parts by weight of an inorganic filler.

[0014] Further, the modified graphene oxide includes at least one of graphene oxide modified by grafting γ-glycidoxypropyltrimethylsilane or graphene oxide modified by grafting γ-methacryloxypropyltrimethoxysilane.

[0015] Furthermore, the thickness of the substrate layer is 4-6 μm, the sum of the thickness of the first metal layer and the first deposition layer is 1-1.2 μm, and the sum of the thickness of the second metal layer and the second deposition layer is 1-1.2 μm.

[0016] Further, the first deposited layer includes at least one element of copper, nickel, chromium or aluminum, the second deposited layer includes at least one element of copper, nickel, chromium or aluminum, the first metal layer includes at least one element of copper, nickel, chromium or aluminum, and the second metal layer includes at least one element of copper, nickel, chromium or aluminum.

[0017] The embodiment of the present application also provides a method for preparing a current collector, which specifically includes granulation, extrusion, stretching, characterization, pore making, deposition and thickening. Granulation: the raw materials of the substrate layer are mixed and granulated, and the melting point of the granulated material is less than or equal to 80°C; extrusion: the granulated material is put into an extruder for extrusion, and a base film is obtained after cooling; stretching: the base film is biaxially stretched, and then heat-set; pore making: the base film is treated by at least one of heavy ion vertical bombardment or chemical etching to obtain a nuclear pore film; deposition: metal is deposited on the surface of the nuclear pore film to form a first deposition layer and a second deposition layer; thickening: metal is plated on the surface of the first deposition layer and the surface of the second deposition layer to form a first metal layer and a second metal layer to obtain a current collector.

[0018] An embodiment of the present application also provides a battery, which includes any of the above-mentioned current collectors or a current collector prepared by the above-mentioned preparation method.

[0019] The substrate layer of the current collector in the present application has a number of through holes that penetrate the substrate layer, and some of the through holes are provided with deposited conductors, which are connected to the metal on both sides of the substrate layer. The metal on the upper and lower surfaces of the substrate layer can complete the charge balance through the deposited conductor, so that the current collector can enhance the electrical conductivity of the battery. The aperture of the through hole is extremely small, which has little effect on the strength of the substrate layer, so that the current collector still has good strength. The surface resistivity of the current collector in the present application is low, the conductivity efficiency is high, and the energy utilization rate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of a current collector in one embodiment of the present application;

[0021] Figure 2 This is a schematic diagram of a top view of the structure of a substrate layer in one embodiment of the present application;

[0022] Figure 3 This is a schematic diagram of a top view of the structure of a substrate layer in another embodiment of the present application;

[0023] Figure 4 This is a schematic diagram of the cross-sectional structure of a substrate layer in one embodiment of the present application;

[0024] Figure 5 This is a schematic diagram of the cross-sectional structure of a substrate layer in another embodiment of the present application;

[0025] Figure 6 This is a schematic diagram of the cross-sectional structure of a current collector in another embodiment of the present application.

[0026] In the figure: current collector 100, first metal layer 11, first deposition layer 12, substrate layer 13, through hole 131, nuclear pore membrane 132, core layer 1321, surface layer 1322, second deposition layer 14, second metal layer 15, deposition conductor 16, dielectric layer 17. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the specific implementation manner of the present application will be clearly and completely described below in conjunction with the drawings in the implementation manner of the present application.

[0028] The present application embodiment provides a Figure 1The current collector 100 shown in the figure includes a first metal layer 11, a first deposition layer 12, a substrate layer 13, a second deposition layer 14 and a second metal layer 15 in sequence. The substrate layer 13 can enhance the mechanical properties of the current collector 100, such as tensile strength and elongation at break. The substrate layer 13 has good puncture resistance, which can avoid short circuits caused by puncture of the current collector 100 and improve the safety performance of the current collector 100. A through hole 131 is provided in the substrate layer 13, and the first deposition layer 12 and the second deposition layer 14 are deposited on both sides of the substrate layer 13 by deposition. During surface deposition, metal particles penetrate into at least part of the through holes 131 of the substrate layer 13 to form a deposition conductor 16. One end of the deposition conductor 16 is connected to the first deposition layer 12, and the other end is connected to the second deposition layer 14, so that the two sides of the substrate layer 13 are electrically connected, and the surface deposition by chemical plating does not require a high temperature environment and will not damage the substrate layer 13. The first metal layer 11 and the second metal layer 15 can strengthen the surface electrical properties of the current collector 100, reduce surface resistance, and improve energy utilization. The electrical properties on the surfaces of the first metal layer 11 and the second metal layer 15 are charge balanced by the deposited conductor 16, and the electrical properties are more balanced. If the intervals between different through holes 131 are large, the resistance at different positions of the current collector 100 will be different, so the membrane edge needs to be specially treated after cutting. In the embodiment of the present application, the through holes 131 of the current collector 100 are smaller and more densely distributed. The resistance between any two points on the outer surface of the first metal layer 11 and the outer surface of the second metal layer 15 is less than or equal to 100Ω. Therefore, the current collector 100 can be used directly after cutting, and there is no need to perform special treatment on the membrane edge of the current collector 100, which improves the convenience of the current collector 100.

[0029] As an optional embodiment, the ratio of the aperture of the through hole 131 to the thickness of the substrate layer 13 is 1:(8-60). In this ratio range, the metal particles can easily penetrate into the through hole 131 completely, and the substrate layer still maintains a high mechanical strength. Preferably, the ratio of the aperture of the through hole 131 to the thickness of the substrate layer 13 is 1:(20-50).

[0030] As an optional embodiment, the ratio of the aperture of the through hole 131 to the thickness of the first metal layer 11 is 1:(2-12). In this ratio range, the resistivity between the deposited conductor 16 filled in the through hole 131 and the first metal layer 11 is small, making the electrical properties of the two sides of the current collector 100 more uniform. Preferably, the ratio of the aperture of the through hole 131 to the thickness of the first metal layer 11 is 1:(5-10).

[0031] As an optional embodiment, the aperture of the through hole 131 is 100-500nm. When the aperture of the through hole 131 is large, the mechanical properties of the substrate layer 13 decrease greatly, resulting in a decrease in the tensile strength of the substrate layer 13, and it is easy to break and crack during the production of the current collector 100. Since the size of the through hole 131 is small (nanoscale), and the aperture size of the through hole 131 in the same substrate layer 13 is not necessarily the same, conventional conductors are difficult to apply to the substrate layer 13 in the embodiment of the present application. The embodiment of the present application uses a deposition method to allow metal particles to penetrate into the through hole 131, and directly forms a layer deposition conductor 16 in the through hole 131. When the aperture of the through hole 131 is small, it is difficult for metal particles to penetrate, and it is easy to cause incomplete penetration of metal particles, thereby affecting the resistance of the current collector 100. When the aperture of the through hole 131 is 100-500nm, the mechanical strength of the substrate layer 13 is high, and metal particles are also easy to penetrate into the through hole 131. Preferably, the diameter of the through hole 131 is 120-200 nm.

[0032] As an optional embodiment, the hole density of the through hole 131 is 1.1×10 7 -1.6×10 8 Hole / cm 2 The porosity of the substrate layer 13 is 3%-20%. The through holes 131 may be arranged regularly (e.g. Figure 2 ), or it can be randomly arranged (as shown in Figure 3 When the porosity or pore density is too high, the mechanical properties of the substrate layer 13 are low, the tensile strength of the substrate layer 13 is low, and the substrate layer 13 is easy to break or fracture during production. When the porosity or pore density is too low, the number of conductors in the through hole 131 is small, the flux between the first metal layer 11 and the second metal layer 15 becomes smaller, the charge channel is reduced, the resistance of the current collector 100 increases, and the power-on effect becomes worse. The porosity of the substrate layer 13 is 3%-20% and the pore density of the through hole 131 is 1.1×10 7 -1.6×10 8 Hole / cm 2 The base material layer 13 can have sufficient mechanical strength and good electrical conduction effect.

[0033] As an optional embodiment, the thickness of the current collector can be adjusted according to the use requirements. When the substrate layer 13 is thicker, the strength of the substrate layer 13 is higher, and the mechanical properties of the current collector 100 are better. When the substrate layer 13 is thinner, the current collector 100 is thinner and has a higher energy density. The thickness of the substrate layer 13 is preferably 4-6μm. Reducing the thickness of the substrate layer 13 can increase the energy density of the current collector 100, which meets the demand for thinness, but as the thickness of the substrate layer 13 decreases, the mechanical strength of the substrate layer 13 will decrease, and the difficulty of preparation will increase. The thickness of the substrate layer 13 is 4-6μm, which enables the substrate layer 13 to have the advantages of high mechanical strength, low difficulty in preparation and high energy density. In actual use, the thickness of the substrate layer 13 can be set according to specific needs.

[0034] As an optional embodiment, the thickness of the first deposition layer 12 is 60-100nm, and the thickness of the second deposition layer 14 is 60-100nm. The first deposition layer 12 and the second deposition layer 14 have a certain thickness, so that the metal particles can fully penetrate into the through hole 131, and improve the mechanical strength of the first deposition layer 12 and the second deposition layer 14. The high thickness of the first deposition layer 12 and the second deposition layer 14 can also improve the bonding ability between the first deposition layer 12 and the second deposition layer 14 and other layers, and improve the structural stability of the current collector 100. The first deposition layer 12 and the second deposition layer 14 should not be too thick. When the thickness of the first deposition layer 12 and the second deposition layer 14 is too large, the thickness uniformity of the current collector will deteriorate. When the first deposition layer 12 and the second deposition layer 14 have a certain thickness, the first deposition layer 12 and the second deposition layer 14 are thickened by any one of vacuum evaporation, magnetron sputtering, chemical plating or water electroplating to form the first metal layer 11 and the second metal layer 15, which can improve the production efficiency of the current collector 100. The first metal layer 11 and the second metal layer 15 can be adjusted to any thickness as required. Preferably, the sum of the thickness of the first metal layer 11 and the first deposition layer 12 is 1-1.2 μm, and the sum of the thickness of the second metal layer 15 and the second deposition layer 14 is 1-1.2 μm, so that the surface resistivity of the current collector 100 is low and meets the requirements of lightweight use.

[0035] As an optional implementation, Figure 4 As shown, the substrate layer 13 includes a nuclear pore membrane 132. The nuclear pore membrane layer is formed by irradiating a polymer membrane with capillaries using high-energy rays. By controlling the irradiation conditions and etching conditions of the high-energy rays, nuclear pore membrane layers with different pore densities and pore sizes can be obtained. The nuclear pore membrane has high mechanical strength and good flexibility, and can improve the service life and reliability of the current collector 100. The modified nuclear pore membrane is modified by using a coupling agent to modify the main resin of graphene oxide and the nuclear pore membrane, thereby improving the compatibility between the various materials and further improving the strength of the nuclear pore membrane.

[0036] As an optional embodiment, the nuclear pore membrane 132 is made of a main resin, modified graphene oxide, a coupling agent and an inorganic filler. In parts by weight, the raw materials of the modified nuclear pore membrane include 1000 parts by weight of the main resin, 10-36 parts by weight of modified graphene oxide, 5-18 parts by weight of a coupling agent and 1-6 parts by weight of an inorganic filler.

[0037] As an optional implementation, Figure 4 As shown, the nuclear pore membrane 132 includes a core layer 1321 and a surface layer 1322. The surface layer 1322 can be disposed on one side of the core layer 1321 (e.g. Figure 4 ), or may be disposed on both sides of the core layer 1321 (as shown Figure 5 The core layer 1321 and the surface layer 1322 have a mass ratio of (80-90):(10-20). The core layer 1321 and the surface layer 1322 are made of a main resin, modified graphene oxide, a coupling agent and an inorganic filler. In parts by weight, the core layer 1321 includes 1000 parts by weight of the main resin, 15-35 parts by weight of the modified graphene oxide, 7.5-17 parts by weight of the coupling agent and 2-4 parts by weight of the inorganic filler; the surface layer 1322 includes 1000 parts by weight of the main resin, 10-18 parts by weight of the modified graphene oxide, 5-12 parts by weight of the coupling agent and 0.1-0.6 parts by weight of the inorganic filler.

[0038] As an optional embodiment, the main resin includes at least one of polyester, polyimide or polyolefin. Polyester, polyimide or polyolefin has better mechanical properties such as tensile strength and elongation at break, which can improve the safety performance of the current collector 100. Preferably, the main resin is at least one of polyester or polyimide. Polyester or polyimide has good mechanical properties and a high melting point, and can be applied to a variety of processes.

[0039] As an optional embodiment, the modified graphene oxide includes graphene oxide modified by oxysilane. Preferably, the modified graphene oxide includes at least one of graphene oxide grafted with γ-glycidyloxypropyltrimethylsilane (KH560) or graphene oxide grafted with γ-methacryloxypropyltrimethoxysilane (KH570). The modified equation of graphene oxide is as follows:

[0040]

[0041] The reaction of silane coupling agent with graphene oxide is usually bonded with graphene oxide in the form of Si-O-Si and Si-OC bonds to form stable covalent bonds. The above reaction equation only lists some forms of the reaction products, but the reaction products are not limited to the forms shown in the above reaction equation. The two-dimensional plane and the edge of the sheet of graphene oxide contain a large number of polar groups such as hydroxyl, epoxy, and carboxyl groups, which makes it easy for pure graphene oxide monomers to condense and agglomerate to form small particles. The dispersion of graphene oxide in the polymer matrix is ​​improved by modifying the graphene oxide, reducing the interfacial interaction and reducing the interlayer van der Waals force. More preferably, the modified graphene oxide includes graphene oxide grafted with γ-methacryloxypropyltrimethoxysilane. Modified graphene oxide can improve the dispersion of the main resin, make the molecular arrangement after the film is stretched and oriented more uniform, and make the crystallization effect and orientation molding effect of the main resin better.

[0042] As an optional embodiment, the coupling agent includes at least one of the oxysilane coupling agents. The coupling agent can couple inorganic bodies such as inorganic fillers and modified graphene oxide with organic bodies such as main resins, so that the obtained substrate layer has better mechanical properties, higher water resistance, heat resistance and weather resistance.

[0043] As an optional implementation, the coupling agent and the oxysilane used for graphene oxide modification are the same oxysilane. Keeping the coupling agent and the modified material of graphene oxide consistent can improve the compatibility between the materials, make the material mixing more uniform, and make the substrate layer have better performance.

[0044] As an optional embodiment, the inorganic filler includes but is not limited to at least one of silicon oxide, barium sulfate, calcium carbonate, kaolin or glass fiber. The inorganic filler can increase the anti-adhesion property of the substrate layer and improve the strength of the substrate layer. Preferably, the inorganic filler includes at least one of silicon oxide or calcium carbonate, and the particle size of silicon oxide or calcium carbonate is small, which is more conducive to high-precision grinding of the substrate layer; inorganic particles will cause microscopic parts of the surface to bulge after film formation, improve roughness and surface adhesion, and too large a particle size will increase the brittleness of the substrate and the surface roughness will be too large, which will be unfavorable for subsequent processing.

[0045] As an optional embodiment, the first deposition layer 12 includes at least one element of copper, nickel, chromium or aluminum, and the second deposition layer 14 includes at least one element of copper, nickel, chromium or aluminum. The first deposition layer 12 and the second deposition layer 14 can be pure metal layers or alloy layers containing the aforementioned metal elements. These metal elements have good conductivity and ductility, which can ensure that the current collector 100 has good electrical properties and flexibility. The first metal layer 11 includes at least one element of copper, nickel, chromium or aluminum, and the second metal layer 15 includes at least one element of copper, nickel, chromium or aluminum. The materials selected for the first metal layer and the first deposition layer 12 can be the same or different. The first metal layer 11 and the second metal layer 15 can be pure metal layers or alloy layers containing the aforementioned metal elements. The materials selected for the second metal layer 15 and the second deposition layer 14 can be the same or different. The first metal layer 11, the first deposition layer 12, the second deposition layer 14 and the second metal layer 15 can be selected according to the material matching of the battery.

[0046] As an optional implementation, Figure 6 As shown, the current collector 100 further includes a dielectric layer 17, which is disposed at least one of between the substrate layer 13 and the first deposition layer 12 or between the substrate layer 13 and the second deposition layer 14. The dielectric layer 17 can improve the adhesion between the substrate layer 13 and the metal particles, making the structure of the current collector 100 more stable. The dielectric layer 17 can also prevent the first deposition layer 12 and the second deposition layer 14 from being separated from the substrate layer 13 during processing or use.

[0047] As an optional embodiment, the dielectric layer 17 includes at least one of a titanate layer and an aqueous polyurethane layer. The above two dielectric layers 17 have good adhesion with metal particles, which can improve the stability between the first deposition layer 12 or the second dielectric layer 17 and the substrate layer 13.

[0048] The embodiment of the present application also provides a method for preparing a current collector 100, which is used to prepare the above-mentioned current collector 100. The preparation method specifically includes granulation, extrusion, stretching, characterization, pore making, deposition and thickening. Granulation is to mix the prepared materials and then re-granulate them. Extrusion is to put the granulated materials into an extruder for extrusion, and after cooling, a base film is obtained. Stretching is to perform biaxial stretching on the base film, and then perform heat setting treatment after stretching. Pore making is to treat the base film by at least one of heavy ion vertical bombardment or chemical etching to obtain a nuclear pore membrane 132, that is, a composite current collector substrate layer 13. Deposition is to deposit metal on the surface of the substrate layer 13 to form a first deposition layer 12 and a second deposition layer 14; thickening is to plate metal on the surface of the first deposition layer 12 and the surface of the second deposition layer 14 to form a first metal layer 11 and a second metal layer 15 to obtain the current collector 100.

[0049] As an optional implementation, oxysilane can be used to modify graphene oxide before granulation. The oxysilane is dissolved in anhydrous ethanol and then added to the aqueous solution of graphene oxide, followed by ultrasonic treatment and stirring; hydrochloric acid is added and the solution is adjusted to weak acidity, heated to 50°C for reaction for a period of time, and then heated to 70°C to continue the reaction; finally, it is cooled to room temperature, and unreacted by-products (recyclable) are isolated by centrifugation and washing, and the collected products are placed in an oven for drying to obtain modified graphene oxide.

[0050] As an optional implementation, after the main resin, modified graphene oxide, coupling agent and inorganic filler are mixed, modified and re-granulated, the granulated materials can be mixed and melted, and a modified melt can be prepared by a single-screw extruder or a twin-screw extruder. The modified melt is then laminated through a two-layer or three-layer hanger-type die head to form a cast polyester sheet with an A / B or A / B / A structure, and then cooled and solidified by a chilled roller to obtain a modified base film.

[0051] As an optional embodiment, the granulated material is visually colorless and transparent or white and transparent, and the thermal deformation temperature is greater than or equal to 80° C. The diameter of the visible stain on the melt of the granulated material is less than or equal to 0.2 mm.

[0052] As an optional embodiment, stretching includes longitudinal stretching and transverse stretching. The modified base film can be longitudinally stretched by roller differential speed. During longitudinal stretching, the preheating temperature is 100-120°C, the heating temperature is 130-155°C, and the longitudinal stretching ratio is 3.0-4.5 times. After the longitudinal stretching is completed and cooled, transverse stretching is performed, and the film that has been longitudinally stretched is clamped with a chain clamp structure for transverse stretching. The transverse stretching temperature must be higher than the glass transition temperature (T g ), but must be lower than the melting temperature of the main resin (T m ). Preferably, during transverse stretching, the preheating temperature is 110-130°C, the heating temperature is 130-155°C, and the stretching ratio is 3.8-5.5 times.

[0053] As an optional embodiment, the temperature of heat setting is 240-260°C.

[0054] As an optional implementation, deposition adopts a surface deposition process, which can make the metal material fully penetrate into the through hole 131, realize electrical connection between the two sides of the substrate layer 13, and chemical metal plating does not require a high temperature environment and will not damage the substrate layer 13. The surface deposition process allows metal particles to adhere to the surface of the substrate layer 13 at a relatively low temperature, which facilitates the subsequent layer thickness operation and improves the film yield.

[0055] As an optional embodiment, before deposition, a dielectric layer can be coated on the surface of the substrate layer 13 to enhance the adhesion between the dielectric layer surface and the metal particles. The coated dielectric layer has a higher adhesion ability to the metal when deposited on the surface, which can improve the film yield of surface deposition.

[0056] As an optional implementation, vacuum evaporation is used for thickening. Vacuum evaporation is used to thicken the surface of the first deposition layer and the second deposition layer to enhance the surface electrical properties of the composite current collector, reduce the surface resistivity, and reduce the resistance of the current collector 100. Vacuum evaporation has a faster thickening speed and is more suitable for mass production.

[0057] The present application also provides a battery, which includes any of the above-mentioned current collectors 100. The current collector 100 in the present application has good mechanical properties and low surface resistivity, which can improve the energy utilization rate of the battery and increase the service life of the battery. The current collector 100 in the present application does not require the preparation of new composite materials, and the process is simple and easy to produce.

[0058] The present application is further described below in conjunction with embodiments, but the protection scope of the present application is not limited to the embodiments.

[0059] Example 1

[0060] like Figure 6 As shown, a current collector 100 includes a first metal layer 11, a first deposition layer 12, a dielectric layer 17, a substrate layer 13, a dielectric layer 17, a second deposition layer 14, and a second metal layer 15 in sequence. A through hole 131 is provided in the substrate layer 13. The current collector 100 also includes a deposition conductor 16, which is located in at least part of the through hole 131 of the substrate layer 13, wherein the deposition layer is deposited by surface chemical deposition, and the metal layer is vacuum evaporated.

[0061] Specifically, the substrate layer 13 includes a 4 μm thick PET modified core pore membrane (core pore membrane 132 with PET as the main resin), and the pore density of the substrate layer 13 is 1.0×10 8 Hole / cm 2 , the porosity is 12%; the pore size of the through hole 131 is 120nm; the first deposition layer 12 is a 60nm copper layer, and the second deposition layer 14 is a 60nm copper layer; the first metal layer 11 is a copper layer, and the second metal layer 15 is a copper layer; the sum of the thickness of the first metal layer 11 and the first deposition layer 12 is 1μm, and the sum of the thickness of the second metal layer 15 and the second deposition layer 14 is 1μm.

[0062] Example 2

[0063] Except for the following technical features, the rest is the same as Example 1.

[0064] The thickness of the base material layer 13 is 5 μm.

[0065] Example 3

[0066] Except for the following technical features, the rest is the same as Example 1.

[0067] The thickness of the base material layer 13 is 6 μm.

[0068] Example 4

[0069] Except for the following technical features, the rest is the same as Example 1.

[0070] The thickness of the base material layer 13 is 7 μm.

[0071] Example 5

[0072] Except for the following technical features, the rest is the same as Example 1.

[0073] The first deposition layer 12 , the second deposition layer 14 , the first metal layer 11 and the second metal layer 15 are all nickel layers.

[0074] Example 6

[0075] Except for the following technical features, the rest is the same as Example 1.

[0076] The first deposition layer 12 , the second deposition layer 14 , the first metal layer 11 , and the second metal layer 15 are all chromium layers.

[0077] Example 7

[0078] Except for the following technical features, the rest is the same as Example 1.

[0079] The first deposition layer 12 , the second deposition layer 14 , the first metal layer 11 , and the second metal layer 15 are all aluminum layers.

[0080] Example 8

[0081] Except for the following technical features, the rest is the same as Example 1.

[0082] The diameter of the through hole 131 is 150 nm, and the thickness of the first deposition layer 12 and the second deposition layer 14 are both 75 nm.

[0083] Example 9

[0084] Except for the following technical features, the rest is the same as Example 1.

[0085] The diameter of the through hole 131 is 200 nm, and the thickness of the first deposition layer 12 and the second deposition layer 14 are both 100 nm.

[0086] Example 10

[0087] Except for the following technical features, the rest is the same as Example 1.

[0088] The diameter of the through hole 131 is 100 nm.

[0089] Embodiment 11

[0090] Except for the following technical features, the rest is the same as Example 1.

[0091] The diameter of the through hole 131 is 500 nm, and the thickness of the first deposition layer 12 and the second deposition layer 14 are both 100 nm.

[0092] Example 12

[0093] Except for the following technical features, the rest is the same as Example 1.

[0094] The pore density of the substrate layer 13 is 1.1×10 7 Hole / cm 2 , the porosity is 3%.

[0095] Embodiment 13

[0096] Except for the following technical features, the rest is the same as Example 1.

[0097] The pore density of the substrate layer 13 is 1.6×10 8 Hole / cm 2 , the porosity is 20%.

[0098] Embodiment 14

[0099] Except for the following technical features, the rest is the same as Example 1.

[0100] The sum of the thicknesses of the first metal layer 11 and the first deposition layer 12 is 1.2 μm, and the sum of the thicknesses of the second metal layer 15 and the second deposition layer 14 is 1.2 μm.

[0101] Embodiment 15

[0102] Except for the following technical features, the rest is the same as Example 1.

[0103] The substrate layer 13 is an ordinary PET nucleopore membrane (the nucleopore membrane is not modified, and PET is used as the ordinary nucleopore membrane layer 131 of the main resin).

[0104] Comparative Example 1

[0105] A current collector 100 includes a first metal layer 11, a first deposition layer 12, a dielectric layer 17, a substrate layer 13, a dielectric layer 17, a second deposition layer 14 and a second metal layer 15 in sequence.

[0106] Specifically, the substrate layer 13 is a common PET film with a thickness of 4 μm; the first deposition layer 12 is a copper layer with a thickness of 60 nm, and the second deposition layer 14 is a copper layer with a thickness of 60 nm; the first metal layer 11 is a copper layer, and the second metal layer 15 is a copper layer; the sum of the thicknesses of the first metal layer 11 and the first deposition layer 12 is 1 μm, and the sum of the thicknesses of the second metal layer 15 and the second deposition layer 14 is 1 μm.

[0107] Comparative Example 2

[0108] Except for the following technical features, the rest is the same as Example 1.

[0109] The current collector 100 includes a first metal layer 11 , a first deposition layer 12 , a substrate layer 13 , a second deposition layer 14 and a second metal layer 15 in sequence.

[0110] Comparative Example 3

[0111] A current collector 100 includes a first metal layer 11, a substrate layer 13, and a second metal layer 15 in sequence. The substrate layer 13 is provided with a through hole 131. The current collector 100 also includes a deposited conductor 16, which is located in at least part of the through hole 131 of the substrate layer 13.

[0112] Specifically, the substrate layer 13 is a 4 μm thick PET modified nuclear pore membrane, and the pore density of the substrate layer 13 is 1.0×10 8 Hole / cm 2 , the porosity is 12%; the aperture of the through hole 131 is 120nm; the first metal layer 11 is a 1μm thick copper layer, and the second metal layer 15 is a 1μm thick copper layer, wherein the metal layer is obtained by vacuum evaporation without the deposition step.

[0113] Comparative Example 4

[0114] A current collector 100 includes a first deposition layer 12, a substrate layer 13, and a second deposition layer 14 in sequence.

[0115] Specifically, the substrate layer 13 is a 4 μm thick PET modified nuclear pore membrane, and the pore density of the substrate layer 13 is 1.0×10 8 Hole / cm 2 , the porosity is 12%; the aperture of the through hole 131 is 120nm; the first deposition layer 12 is a 1μm thick copper layer, and the second deposition layer 14 is a 1μm thick copper layer, wherein the metal layer is deposited only by surface chemical deposition.

[0116] 1. Performance test:

[0117] The performance test was performed on the current collector 100 in the above embodiment and comparative example.

[0118] 1. Tensile strength: The longitudinal tensile strength of the composite current collector of the product is tested. The testing method refers to the testing standard GB / T 1040.1-2018.

[0119] 2. Resistance between the upper and lower surfaces: Cut the material into several small pieces of 20mm×20mm, use an ohmmeter to measure the resistance between the upper and lower surfaces, and take the arithmetic average.

[0120] 3. Sheet resistance: Use a 4-probe sheet resistance meter to test the sheet resistance of the product composite current collector, use the four-contact method to detect the material sheet resistance, and take the arithmetic average

[0121] 4. Film yield: After the composite current collector is prepared on the finished substrate mother roll, the product is screened. If the metal layer attachment process damages the substrate, it is NG. The film yield is the number of meters of composite current collector that are not NG / meter of substrate.

[0122] 2. Performance test results:

[0123] The performance test results of the above embodiments and comparative examples are shown in Table 1.

[0124]

[0125] As can be seen from the table, compared with Example 1, Examples 1 to 15 use a nuclear pore membrane, and the tensile strength is slightly lower than that of the traditional composite current collector, but the conductivity is significantly improved, especially after the upper and lower surfaces are connected by metal deposition on the modified nuclear pore membrane to achieve conductor connection, the resistance is significantly reduced, which can effectively reduce the energy loss of the battery and improve the energy utilization rate. Compared with Example 1, Example 2 is different from Example 1 in that the surface of the base layer is not coated with a dielectric layer on the surface of the base film, which reduces the adhesion of the surface of the substrate layer, resulting in a decrease in the film yield of Example 2. Compared with Example 1, Example 3 does not have a first deposition layer and a second deposition layer in Example 3, and the film yield is reduced; except for the data in the table, the substrate layer in Example 3 is not protected by the first deposition layer and the second deposition layer. Due to the high process temperature of the evaporated metal layer, the current collector is very prone to film breakage after the metal layer is plated. Compared with Example 1, in Comparative Example 4, the first metal layer and the second metal layer are not provided, and the film rate is decreased; in addition to the data in the table, the current collector of Comparative Example 4 also has defects such as uneven thickness distribution. It can be seen from the comparison of Example 15 with Example 1 that the tensile strength of the modified nuclear pore membrane is significantly better than that of the unmodified nuclear pore membrane. After the main resin is modified, the strength of the substrate layer can be significantly improved. In addition, it can be seen from the comparison of Examples 3 and 4 with Example 1 that the thickness of the substrate layer has a certain effect on the resistivity, etc. The main reason is that after the thickness of the substrate layer increases, the filling rate of the metal material in the pores decreases, resulting in a sharp decrease in the actual conductive domain and an increase in the resistivity. Compared with the examples, it can be seen from Examples 5 and 6 that the choice of metal material has an effect on the resistivity. The main reason is that the metal material itself affects the filling rate in the pores. The filling rates of metal materials such as nickel and chromium in the pores are not as good as copper. At the same time, metal materials such as nickel and chromium also have higher resistivity than copper.

[0126] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this application.

Claims

1. A current collector, characterized in that: include: A first metal layer; a first deposition layer, the first deposition layer being disposed on one side of the first metal layer; A substrate layer, the substrate layer is disposed on a side of the first deposition layer away from the first metal layer, the substrate layer is provided with a through hole, and the ratio of the aperture of the through hole to the thickness of the substrate layer is 1:(8-60); a second deposition layer, the second deposition layer being disposed on a side of the substrate layer away from the first deposition layer; a second metal layer, the second metal layer being disposed on a side of the second deposition layer away from the substrate layer; A deposited conductor is located in at least a portion of the through holes of the substrate layer, one end of the deposited conductor is connected to the first deposited layer, and the other end of the deposited conductor is connected to the second deposited layer.

2. The current collector according to claim 1, characterized in that: The current collector further includes a dielectric layer, and the dielectric layer is disposed at least one of between the substrate layer and the first deposition layer or between the substrate layer and the second deposition layer.

3. The current collector according to claim 1, characterized in that: The hole density of the through holes in the substrate layer is 1.1×10 7 -1.6×10 8 Pieces / cm 2 The porosity of the substrate layer is 3%-20%.

4. The current collector according to claim 1, characterized in that: The ratio of the aperture of the through hole to the thickness of the first metal layer is 1:(2-12); Preferably, the through hole has a diameter of 100-500 nm.

5. The current collector according to claim 1, characterized in that: The substrate layer includes a nuclear pore membrane; In parts by weight, the preparation material of the nuclear pore membrane includes 1000 parts by weight of a main resin, 10-36 parts by weight of modified graphene oxide, 5-18 parts by weight of a coupling agent and 1-6 parts by weight of an inorganic filler.

6. The current collector according to claim 1, characterized in that: The substrate layer includes a nuclear pore membrane, the nuclear pore membrane includes a core layer and a surface layer, the surface layer is arranged on at least one side of the core layer, and the mass ratio of the core layer to the surface layer is (80-90):(10-20); Preferably, in parts by weight, the preparation material of the core layer includes 1000 parts by weight of a main resin, 15-35 parts by weight of modified graphene oxide, 7.5-17 parts by weight of a coupling agent and 2-4 parts by weight of an inorganic filler; the preparation material of the surface layer includes 1000 parts by weight of a main resin, 10-18 parts by weight of modified graphene oxide, 5-12 parts by weight of a coupling agent and 0.1-0.6 parts by weight of an inorganic filler.

7. The current collector according to claim 5 or claim 6, characterized in that: The modified graphene oxide includes at least one of graphene oxide grafted with γ-glycidyloxypropyltrimethylsilane and graphene oxide grafted with γ-methacryloxypropyltrimethoxysilane.

8. The current collector according to claim 1, characterized in that: The thickness of the substrate layer is 4-6 μm, the sum of the thickness of the first metal layer and the first deposition layer is 1-1.2 μm, and the sum of the thickness of the second metal layer and the second deposition layer is 1-1.2 μm; Preferably, the first deposited layer includes at least one element of copper, nickel, chromium or aluminum, the second deposited layer includes at least one element of copper, nickel, chromium or aluminum, the first metal layer includes at least one element of copper, nickel, chromium or aluminum, and the second metal layer includes at least one element of copper, nickel, chromium or aluminum.

9. A method for preparing the current collector according to any one of claims 1 to 8, characterized in that: The preparation method comprises: Granulation: mixing and granulating the raw materials of the substrate layer, wherein the melting point of the granulated material is less than or equal to 80° C.; Extrusion: The granulated material is put into an extruder for extrusion, and the base film is obtained after cooling; Stretching: The base film is biaxially stretched and then heat-set; Pore ​​formation: treating the basement membrane by at least one of heavy ion vertical bombardment or chemical etching to obtain a nuclear pore membrane; Deposition: depositing metal on the surface of the nuclear pore membrane to form the first deposition layer and the second deposition layer; Thickening: plating metal on the surface of the first deposition layer and the surface of the second deposition layer to form the first metal layer and the second metal layer to obtain the current collector.

10. A battery, characterized in that: The battery comprises the current collector according to any one of claims 1 to 8 or the current collector prepared by the preparation method according to claim 9.

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