Current collector and electrode plate manufacturing method

Abstract

Disclosed are a current collector, an electrode plate, and a method of manufacturing a current collector, the current collector comprising a support layer, a first conductive layer, and a second conductive layer, the support layer having a first surface and a second surface disposed opposite each other, the first conductive layer being disposed on the first surface and / or the second surface of the support layer in a mesh-like structure, and the second conductive layer being disposed on a surface of the first conductive layer remote from the support layer.

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 202111162977.X, entitled "Method for manufacturing current collector, electrode plate and current collector," filed with the State Intellectual Property Administration of the People's Republic of China on September 30, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of batteries, and more particularly to current collectors, electrode plates, and methods for manufacturing current collectors. [Background technology]

[0003] Lithium-ion batteries are widely used in the fields of portable power supplies and energy storage. As society develops, people's demands for higher energy density in power supplies become higher and higher, making it increasingly urgent to improve the energy density of lithium-ion batteries.

[0004] In related technologies, the most fundamental means of improving energy density is to fundamentally improve energy density by changing the battery material system, but it is extremely difficult to innovate and commercialize battery materials in a short period of time.

[0005] Therefore, when traditional materials are limited, how to design batteries with higher energy density based on technological innovations in current collector structure to meet the demand for longer driving range is a problem that the industry has been considering for a long time and needs to be solved as soon as possible. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present application is to provide a current collector, an electrode plate, and a method for manufacturing the current collector. [Means for solving the problem]

[0007] According to a first aspect of the present invention, there is provided a current collector, the current collector including a support layer, a first conductive layer, and a second conductive layer, the support layer having a first surface and a second surface disposed opposite each other; the first conductive layer is disposed on the first surface and / or the second surface of the support layer in a mesh-like structure; The second conductive layer is disposed on a surface of the first conductive layer remote from the support layer.

[0008] Preferably, the thickness of the first conductive layer is in the range of 0.1 μm to 50 μm.

[0009] Preferably, the thickness of the support layer ranges from 0.1 μm to 20 μm.

[0010] Preferably, the thickness of the current collector is in the range of 1 μm to 100 μm.

[0011] Preferably, the mesh-like structure has an area of ​​less than 0.01 cm 2 ~100cm 2 The mesh includes holes in which

[0012] The mesh structure includes mesh holes, and the mesh holes are surrounded by mesh walls, and the width of the mesh walls ranges from 0.1 mm to 50 mm.

[0013] Preferably, the thickness of the second conductive layer is in the range of 0.1 μm to 50 μm.

[0014] Preferably, the support layer is a voided thermoplastic elastomer layer.

[0015] Preferably, the current collector further comprises a third conductive layer, the third conductive layer being disposed on the first surface or the second surface of the support layer in a mesh-like structure.

[0016] Preferably, the first conductive layer is disposed on a first surface of the support layer, and the third conductive layer is disposed on a second surface of the support layer.

[0017] Preferably, the first conductive layer is disposed on a second surface of the support layer, and the third conductive layer is disposed on a first surface of the support layer.

[0018] Preferably, the second conductive layer is disposed on the surface of the third conductive layer remote from the support layer.

[0019] Preferably, the first conductive layer is a metal member, and the third conductive layer is a metal member.

[0020] According to a second aspect of the present invention, there is provided an electrode plate, comprising the current collector according to the first aspect and an electrode paste layer formed on the second conductive layer.

[0021] According to a third aspect of the present application, there is provided a method for producing a current collector, the method comprising: providing a support layer; forming a first conductive layer on the first surface and / or the second surface of the support layer using at least one of a printing technique, a letterpress printing technique, a deposition technique, and a magnetron sputtering technique, such that the first conductive layer is arranged on the support layer in a mesh-like structure; forming a second conductive layer over the entire surface of the first conductive layer; and drying the second conductive layer to harden the second conductive layer on the surface of the first conductive layer to produce the current collector. [Effects of the Invention]

[0022] The technical effect of the present invention is to provide a current collector. The current collector includes a support layer, a mesh-like first conductive layer, and a second conductive layer formed on the first conductive layer. The support layer satisfies the strength requirements of the current collector, and the first and second conductive layers provide electrical conductivity for the current collector. In an embodiment of the present invention, when the mesh-like first conductive layer is formed on the support layer, the weight per unit area of ​​the current collector is reduced and the energy density of the battery is improved. The mesh-like first conductive layer is formed on the support layer, and the entire current collector may have a porous structure. The porous current collector allows ions to pass through in a direction perpendicular to the thickness of the current collector, i.e., the current collector allows lithium ions to pass through, expanding the application range of the current collector.

[0023] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application, taken in conjunction with the drawings. [Brief explanation of the drawings]

[0024] The drawings, which are incorporated into the specification, illustrate embodiments of the present application and, together with the specification, serve to explain the principles of the present application.

[0025] [Figure 1] 1 is a first schematic diagram of a current collector according to the present invention. [Figure 2] FIG. 2 is a second schematic diagram of the current collector of the present invention. [Figure 3] FIG. 3 is a third schematic diagram of the current collector of the present invention. [Figure 4] FIG. 4 is a fourth schematic diagram of the current collector of the present invention. [Figure 5] FIG. 5 is a fifth schematic diagram of the current collector of the present invention. [Figure 6] FIG. 6 is a sixth schematic diagram of the current collector of the present invention. [Figure 7] FIG. 2 is a schematic diagram illustrating the configuration of a first conductive layer of a current collector according to the present invention. [Figure 8] 1 is a flowchart of the manufacturing process of the current collector of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0026] Various exemplary embodiments of the present application will be described in detail below with reference to the drawings. Unless otherwise specified, the relative arrangement of components and steps, numerical expressions and values ​​described in these embodiments do not limit the scope of the present application.

[0027] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the present application, its application, or uses.

[0028] Techniques and devices known to those skilled in the art are not discussed in detail, but where appropriate, said techniques and devices should be considered part of the specification.

[0029] In all examples shown and discussed herein, any specific values ​​should be construed as illustrative only and not limiting, and therefore, other examples of the exemplary embodiments may have different values.

[0030] It should be noted that similar reference numerals and letters represent similar elements in the following drawings, so that once any element is defined in one drawing, it need not be further discussed in subsequent drawings.

[0031] Given the limitations of currently available materials, the industry has considered reducing the proportion of inactive components in batteries to improve battery energy density. Porous current collector technology is an important technique for reducing the proportion of inactive components, and porous current collectors can also improve battery energy density. Currently, types of porous current collectors include metal foam sheets, perforated metal foil materials, and carbon fiber sheets. In conventional porous current collector technology, metal foam sheets have the disadvantage of being thick and having a high weight per unit area, which reduces the specific energy density of batteries. Perforated metal foil materials have the disadvantage of being expensive to perforate. Large perforations significantly reduce the strength of the current collector. Carbon fiber sheets, such as carbon cloth, have the disadvantage of being brittle and expensive.

[0032] Based on the above technical problem, a first aspect of the present application provides a current collector. As shown in Figures 1 to 3, the current collector includes a support layer 1, a first conductive layer 2, and a second conductive layer 3.

[0033] The support layer 1 has a first surface 11 and a second surface 12 arranged opposite to each other. The first conductive layer 2 is arranged on the first surface 11 and / or the second surface 12 of the support layer 1 in a mesh-like structure 20. The second conductive layer 3 is disposed on the surface of the first conductive layer 2 remote from the support layer 1.

[0034] In other words, the current collector mainly comprises a support layer 1, a first conductive layer 2, and a second conductive layer 3. The support layer 1 provides structural strength, ensuring the strength of the current collector and meeting the assembly needs of the battery. The support layer 1 also contains voids, allowing lithium ions to pass through. The first conductive layer 2 is formed on the support layer 1, and the second conductive layer 3 is formed on the first conductive layer 2, forming a mesh structure in the conductive layers, giving the entire current collector a porous structure, allowing lithium ions to pass through and ensuring the current collector's lithium ion transport capacity. The porous current collector allows lithium ions to pass through in the direction perpendicular to its two-dimensional surface (i.e., through the thickness of the porous current collector), expanding the application scenarios of the porous current collector. For example, the current collector can be used for electrochemical lithium replenishment.

[0035] 1, the first conductive layer 2 is disposed on the first surface 11 of the support layer 1 in a mesh-like structure 20, the second conductive layer 3 is formed on the first conductive layer 2, and no conductive layer is provided on the second surface 12 of the support layer 1, thus forming a first current collector. The first current collector includes only the support layer 1, the first conductive layer 2, and the second conductive layer 3.

[0036] In another embodiment, as shown in FIG. 2, the first conductive layer 2 is arranged on the second surface 12 of the support layer 1 in a mesh-like structure 20, and the first conductive layer 2 has a second 2 2 is formed on the first surface 11 of the support layer 1, and no conductive layer is provided on the first surface 11 of the support layer 1, thus forming a first current collector. The difference between the structure of the first current collector shown in FIG. 2 and the structure of the first current collector shown in FIG. 1 is that the first conductive layer 2 is provided on a different surface of the support layer 1.

[0037] In another embodiment, as shown in Fig. 3, the first conductive layer 2 is arranged on the first surface 11 and the second surface 12 of the support layer 1 in a mesh-like structure 20, and a third conductive layer is formed on each of the two first conductive layers 2, thus forming a first current collector. The structure of the first current collector shown in Fig. 3 differs from the structures of the first current collectors shown in Figs. 1 and 2 in that, in the first current collector shown in Fig. 3, the first conductive layer 2 is formed on both the first surface 11 and the second surface 12 of the support layer 1, whereas, in the first current collectors shown in Figs. 1 and 2, the first conductive layer 2 is formed only on the first surface 11 or the second surface 12 of the support layer 1.

[0038] In the present embodiment, the first conductive layer 2 is disposed on the support layer 1 in a mesh structure 20. Because the first conductive layer 2 has the mesh structure 20, lithium ions can easily pass through the mesh pores of the mesh structure 20. The mesh structure of the first conductive layer 2 ensures normal lithium ion permeation. Furthermore, the mesh structure 20 of the first conductive layer 2 reduces the weight per unit area of ​​the current collector, improving the energy density of the battery and reducing the internal resistance of the current collector, allowing a large current to be generated and output to the outside. Furthermore, the conductivity of the first conductive layer 2 also ensures the conductivity of the current collector. Therefore, the mesh-like first conductive layer 2 ensures the electron collection and lithium ion transport capabilities of the current collector.

[0039] When the second conductive layer 3 is provided on the surface of the first conductive layer 2 that is remote from the support layer 1, it does not prevent the permeation of lithium ions, and the second conductive layer 3 further improves the electronic conductivity of the current collector. Specifically, the second conductive layer 3 is provided on the entire surface of the first conductive layer 2, and the second conductive layer 3 and the first conductive layer 2 cooperate in the mesh wall 202 (for example, the second conductive layer 3 covering the mesh area makes up for the deficiency of the first conductive layer 2), ensuring the electron collection ability and lithium ion transport ability of the current collector. Specifically, 2 The conductive layer 3 collects electrons in the hollow area of ​​the mesh and does not affect the transport of lithium ions.

[0040] The current collector of the present invention has high strength, light weight, and excellent conductivity, and also has a porous structure to ensure the normal transport of lithium ions.

[0041] In one embodiment, the thickness of the first conductive layer 2 ranges from 0.1 μm to 50 μm. Preferably, the thickness of the first conductive layer 2 ranges from 1 μm to 10 μm.

[0042] In one embodiment, the thickness of the support layer 1 ranges from 0.1 μm to 20 μm, and preferably ranges from 5 μm to 15 μm.

[0043] In one embodiment, the thickness of the second conductive layer 3 ranges from 0.1 μm to 50 μm. Preferably, the thickness of the second conductive layer 3 ranges from 5 μm to 20 μm.

[0044] In one embodiment, the thickness of the current collector is in the range of 1 μm to 100 μm, and preferably in the range of 15 μm to 50 μm.

[0045] Specifically, this embodiment limits the thickness of the first conductive layer 2. When integrating the conductive performance and ion transport performance of the entire current collector, setting the thickness of the first conductive layer 2 within this range reduces the weight per unit area of ​​the current collector and the proportion of inactive materials, without affecting the overall thickness of the current collector, thereby improving the energy density of the battery.

[0046] This embodiment limits the thickness of the support layer 1. By setting the thickness of the support layer 1 within this range, the weight per unit area of ​​the current collector is reduced and the proportion of inactive materials is reduced, without affecting the strength of the entire current collector, and when applied to a battery, the energy density of the battery is improved.

[0047] In this embodiment, the thickness of the second conductive layer 3 is limited. The thickness of the second conductive layer 3 affects the electron collection ability of the current collector of the first conductive layer 2 and the assistance of the second conductive layer 3 in lithium ion transport. As the thickness of the second conductive layer 3 decreases, the current collector collects fewer electrons and improves its lithium ion transport ability. Conversely, the current collector collects more electrons and decreases its lithium ion transport ability. In this embodiment, by controlling the thickness of the second conductive layer 3 within this range, the normal electron collection ability and lithium ion transport ability of the current collector can be effectively improved.

[0048] In this embodiment, the thickness of the manufactured current collector is limited to a reasonable range by limiting the thicknesses of the support layer 1, the first conductive layer 2, and the second conductive layer 3. By limiting the thickness of the current collector to this range, this embodiment ensures the conductivity of the entire current collector while reducing the proportion of inactive materials and ensuring the energy density of the battery.

[0049] In one embodiment, as shown in FIG. 7, the mesh structure 20 includes a plurality of mesh holes 201 arranged in an array, and each mesh hole 201 has an area coverage of 0.01 cm . 2 ~100cm 2 is.

[0050] More specifically, the mesh holes 201 are surrounded by mesh walls 202, and the thickness of the mesh walls 202 ranges from 0.1 mm to 50 mm.

[0051] Specifically, the thickness of the mesh wall 202 affects the conductive performance and weight per unit area of ​​the first conductive layer 2. Regarding how to balance the conductive performance and weight per unit area of ​​the first conductive layer 2, this embodiment limits the thickness of the mesh wall 202. By limiting the thickness of the mesh wall 202 to this range, the weight per unit area of ​​the first conductive layer 2 is reduced, the energy density of the battery is improved, and the conductive performance of the current collector is also ensured.

[0052] In this embodiment, the mesh structure includes a plurality of mesh holes 201 arranged in an array, and the mesh holes 201 are arranged in an array on the support layer 1. The shape of the mesh holes 201 may be rectangular, circular, diamond-shaped, etc. In this embodiment, the shape of the mesh holes 201 is not particularly limited, and in this embodiment, the area range of each mesh hole 201 is 0.01 cm 2 ~100cm 2 and preferably, the area coverage of each mesh hole 201 is 1 cm 2 ~10cm 2 is.

[0053] Specifically, the area of ​​the mesh holes 201 affects the conductive performance of the first conductive layer 2 and the weight per unit area of ​​the current collector. To achieve a balance between the conductive performance of the first conductive layer 2 and the weight per unit area of ​​the first conductive layer 2, this embodiment limits the area of ​​the mesh holes 201. Research has shown that by limiting the area of ​​the mesh holes 201 to this range, the weight per unit area of ​​the first conductive layer 2 is reduced, improving the energy density of the battery and ensuring the conductive performance of the current collector.

[0054] In one embodiment, the support layer 1 is a voided thermoplastic elastomer layer.

[0055] Specifically, a support layer 1 is used as a substrate, a first conductive layer 2 is formed on the support layer 1, and a second conductive layer 3 is formed on the first conductive layer 2. The support layer 1 is a thermoplastic elastomer layer having voids. For example, voids with a diameter of less than 100 μm are formed in the support layer 1.

[0056] In this embodiment, by selecting a thermoplastic elastomer layer as the support layer 1, the structural strength of the current collector is improved.

[0057] Specifically, the thermoplastic elastomer layer is one of a polyolefin-based thermoplastic elastomer layer, a polyurethane-based thermoplastic elastomer layer, and a polyamide-based thermoplastic elastomer layer. The support layer 1 may be a composite membrane layer, which is formed by physically pressing at least two of a polyolefin-based thermoplastic elastomer layer, a polyurethane-based thermoplastic elastomer layer, and a polyamide-based thermoplastic elastomer layer.

[0058] In one specific embodiment, the material of the support layer 1 is the same as the material of the separator of the lithium battery, which ensures that the current collector has a certain strength, meets the production needs of the battery, and ensures normal lithium ion permeability.

[0059] In one embodiment, a first conductive layer 2 having a mesh structure is formed on the surface of a support layer 1 by deposition.

[0060] In one embodiment, the second conductive layer 3 includes a conductive agent and an adhesive, which are uniformly mixed and then placed on the surface of the first conductive layer 2 to form the second conductive layer 3.

[0061] Specifically, the conductive agent is one of carbon black, carbon nanotubes, and graphene. The adhesive is a conductive adhesive, specifically, a PVDF (polyvinylidene fluoride) adhesive, a PTFE (polytetrafluoroethylene) adhesive, a CMC (carboxymethyl cellulose) adhesive, or an SBR (styrene butadiene latex) adhesive.

[0062] The adhesive and conductive agent are mixed in a mass ratio of 0.5:99.5 to 50:50, and a certain solvent (NMP, water, etc.) is added to prepare a paste. The paste is then applied to the surface of the first conductive layer 2 to form the second conductive layer 3.

[0063] In one embodiment, as shown in Figures 4 to 6, the current collector further includes a third conductive layer 4, which is disposed on the first surface 11 or the second surface 12 of the support layer 1 in a mesh-like structure 20.

[0064] The first conductive layer 2 is disposed on the first surface 11 of the support layer 1, and the third conductive layer 4 is disposed on the second surface 12 of the support layer 1. Alternatively, the first conductive layer 2 is disposed on the second surface 12 of the support layer 1, and the third conductive layer 4 is disposed on the first surface 11 of the support layer 1. The third conductive layer 4 is disposed on the first surface 11 or the second surface 12 of the support layer 1 in a mesh-like structure 20, and the second conductive layer 3 is provided on the surface of the third conductive layer 4 remote from the support layer 1.

[0065] Specifically, the current collector further comprises a third conductive layer 4. In one embodiment, the third conductive layer 4 is disposed on the first surface 11 of the support layer 1 in a mesh-like structure 20. In another embodiment, the third conductive layer 4 is disposed on the second surface 12 of the support layer 1 in a mesh-like structure 20.

[0066] 6, the third conductive layer 4 is disposed on the first surface 11 of the support layer 1, the first conductive layer 2 is disposed on the second surface 12 of the support layer 1, and the second conductive layer 3 is formed on the surface of the first conductive layer 2 and the surface of the third conductive layer 4, respectively, thus forming a third current collector. The third current collector includes the support layer 1, the first conductive layer 2, the second conductive layer 3, and the third conductive layer 4.

[0067] Alternatively, in one embodiment, the third conductive layer 4 is disposed on the second surface 12 of the support layer 1, the first conductive layer 2 is disposed on the first surface 11 of the support layer 1, and the second conductive layer 3 is formed on the surface of the first conductive layer 2 and the surface of the third conductive layer 4, respectively, thus forming a third current collector.

[0068] 6, the first conductive layer 2 is disposed on the second surface 12 of the support layer 1, and the third conductive layer 4 is disposed on the first surface 11 of the support layer 1. In this case, the positive electrode paste and the negative electrode paste may be applied to both surfaces of the current collector, respectively, and the current collector may be cut and then used as a cell.

[0069] Alternatively, in one embodiment, as shown in Figure 4, the third conductive layer 4 is disposed on the first surface 11 of the support layer 1 in a mesh-like structure 20, the second conductive layer 3 is formed on the surface of the third conductive layer 4, and no conductive layer is provided on the second surface 12 of the support layer 1, thus forming a second current collector. The second current collector includes only the support layer 1, the third conductive layer 4, and the second conductive layer 3.

[0070] In another embodiment, as shown in FIG. 5, the third conductive layer 4 is arranged on the second surface 12 of the support layer 1 in a mesh-like structure 20, the second conductive layer 3 is formed on the surface of the third conductive layer 4, and no conductive layer is provided on the first surface 11 of the support layer 1, thus forming a second current collector.

[0071] In another embodiment, the third conductive layer 4 is arranged on the first surface 11 and the second surface 12 of the support layer 1 in a mesh-like structure 20, and the second conductive layer 3 is formed on each surface of the two third conductive layers 4, thus forming a second current collector.

[0072] In one specific embodiment, the first conductive layer 2 is a positive electrode conductive layer, and the third conductive layer 4 is a negative electrode conductive layer. Specifically, the support layer 1 conducts only ions, not electrons, and can be considered a battery separator. The first conductive layer 2 is a positive electrode conductive layer located on one side of the support layer 1, and the third conductive layer 4 is a negative electrode conductive layer located on the other side of the support layer 1. Alternatively, the first conductive layer 2 is a negative electrode conductive layer, and the third conductive layer 4 is a positive electrode conductive layer. In this embodiment, the first conductive layer 2 is a positive electrode conductive layer, and the third conductive layer 4 is a negative electrode conductive layer. For example, the positive electrode conductive layer has an aluminum mesh structure, and the negative electrode conductive layer has a copper mesh structure.

[0073] In one embodiment, the positive electrode conductive layer is disposed on the first surface 11 of the support layer 1, and the second conductive layer 3 is formed on the positive electrode conductive layer, thus forming a positive electrode current collector. Alternatively, the positive electrode conductive layer is disposed on the second surface 12 of the support layer 1, and the second conductive layer 3 is formed on the positive electrode conductive layer, thus forming a positive electrode current collector. Alternatively, the positive electrode conductive layer is disposed on both the first surface 11 and the second surface 12 of the support layer 1, and the second conductive layer 3 is formed on the positive electrode conductive layer, thus forming a positive electrode current collector. In other words, the first current collector is the positive electrode current collector.

[0074] In one embodiment, the negative electrode conductive layer is disposed on the first surface 11 of the support layer 1, and the second conductive layer 3 is formed on the negative electrode conductive layer, thus forming a negative electrode current collector. Alternatively, the negative electrode conductive layer is disposed on the second surface 12 of the support layer 1, and the second conductive layer 3 is formed on the negative electrode conductive layer, thus forming a negative electrode current collector. Alternatively, the negative electrode conductive layer is disposed on both the first surface 11 and the second surface 12 of the support layer 1, and the second conductive layer 3 is formed on the negative electrode conductive layer, thus forming a negative electrode current collector. That is, the second current collector is the negative electrode current collector.

[0075] In one embodiment, the support layer 1 conducts only ions, not electrons, and can be considered a battery separator, the first conductive layer 2 being a positive electrode conductive layer located on one side of the support layer 1, and the third conductive layer 4 being a negative electrode conductive layer located on the other side of the support layer 1. For example, the positive electrode conductive layer is disposed on the first surface 11 of the support layer 1, the second conductive layer 3 is formed on the positive electrode conductive layer, and the negative electrode conductive layer is disposed on the second surface 12 of the support layer 1, and the second conductive layer 3 is formed on the negative electrode conductive layer, thus forming a third current collector. That is, the third current collector has a structure in which the positive electrode current collector and the negative electrode current collector are integrated into one body.

[0076] In one embodiment, the first conductive layer 2 is a metal member, and the third conductive layer 4 is a metal member.

[0077] Specifically, the first conductive layer 2 and the third conductive layer 4 are both metal mesh members. The first conductive layer 2 may be a positive electrode conductive layer and the third conductive layer 4 may be a negative electrode conductive layer, or the first conductive layer 2 may be a negative electrode conductive layer and the third conductive layer 4 may be a positive electrode conductive layer.

[0078] When the first conductive layer 2 is a positive electrode conductive layer, the first conductive layer 2 is an aluminum metal member. For example, the first conductive layer 2 of the mesh structure 20 is formed of an aluminum metal member.

[0079] When the third conductive layer 4 is a negative electrode conductive layer, the third conductive layer 4 is a copper metal member. For example, the third conductive layer 4 of the mesh structure 20 is formed of a copper metal member.

[0080] The positive electrode of a lithium-ion battery has a high potential, and the aluminum oxide layer is relatively dense, preventing oxidation of the current collector. However, copper undergoes a lithium absorption reaction at high potential, making it unsuitable for use as a positive electrode conductive layer. Therefore, aluminum foil is generally used as the positive electrode conductive layer. However, the negative electrode has a low potential, and aluminum is prone to forming an aluminum-lithium alloy at low potential. Therefore, copper foil is generally used as the negative electrode conductive layer; copper foil and aluminum foil are not interchangeable.

[0081] According to a second aspect of the present application, there is provided an electrode plate. The electrode plate includes the current collector according to the first aspect and an electrode paste layer formed on the second conductive layer 3. For example, the electrode paste layer is applied or thermally sprayed onto the second conductive layer 3. The electrode plate includes a positive electrode plate and a negative electrode plate.

[0082] In one embodiment, the electrode paste layer includes an electrode active material, a conductive agent, and an adhesive. The active material is a positive electrode active material or a negative electrode active material for a battery. For example, the positive electrode active material includes one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, a ternary material, etc. The negative electrode active material includes a carbon material. For example, the negative electrode active material is graphite. For example, the conductive agent includes one of carbon black, carbon nanotubes, graphene, etc. For example, the adhesive is a conductive adhesive. For example, the adhesive is a PVDF (polyvinylidene fluoride) adhesive, a PTFE (polytetrafluoroethylene) adhesive, a CMC (carboxymethyl cellulose) adhesive, or an SBR (styrene butadiene latex) adhesive.

[0083] In one embodiment, a first conductive layer 2 is disposed on the first surface 11 and / or the second surface 12 of the support layer 1, a second conductive layer 3 is formed on the surface of the first conductive layer 2, thus forming a first current collector, and a positive electrode paste layer is applied to the first current collector, thus forming a first electrode plate, which is a positive electrode plate.

[0084] In one embodiment, the third conductive layer 4 is disposed on the first surface 11 and / or the second surface 12 of the support layer 1, the second conductive layer 3 is formed on the surface of the third conductive layer 4, thus forming a second current collector, and then a negative electrode paste layer is placed on the second current collector, thus forming a second electrode plate which is a negative electrode plate.

[0085] In one embodiment, the first conductive layer 2 is disposed on the first surface 11 of the support layer 1, the second conductive layer 3 is disposed on the first conductive layer 2, a positive electrode paste layer is disposed on the second conductive layer 3, and the third conductive layer 4 is disposed on the second surface 12 of the support layer 1, the second conductive layer 3 is formed on the third conductive layer 4, and a negative electrode paste layer is formed on the second conductive layer 3, thereby forming an integrated structure of the positive electrode plate and the negative electrode plate, and this integrated structure is defined as a third electrode plate. In the third electrode plate, the support layer corresponds to the separator structure of a battery, and the support layer conducts only ions but does not conduct electrons.

[0086] In one embodiment, a cell is provided. The cell includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive and negative electrode plates. When the positive and negative electrode plates are independent structures, the positive electrode plate, separator, and negative electrode plate are wound together to form the cell. Alternatively, the active material layer of a single-sided positive electrode plate and one surface of a support layer 1 of a single-sided negative electrode plate are bonded together, and then wound together to form the cell. This embodiment further reduces the thickness of the cell current collector, improving the energy density of the battery.

[0087] When the positive and negative electrode plates are of an integrated structure, the cell includes a plurality of third electrode plates, with separators disposed between adjacent third electrode plates.

[0088] According to a third aspect of the present application, there is provided a method for producing a current collector. As shown in FIG. 8, the method for producing the current collector includes the following steps: Step S101 of providing a support layer 1; Step S102: forming a first conductive layer 2 on the first surface 11 and / or the second surface 12 of the support layer 1 by using at least one of a printing technique, a letterpress printing technique, a deposition technique, and a magnetron sputtering technique so as to be arranged on the support layer 1 in a mesh-like structure 20; Step S103 of applying paste to the entire surface of the first conductive layer 2 to form a second conductive layer 3; and step S104 of drying the second conductive layer 3 to harden the second conductive layer 3 on the surface of the first conductive layer 2, thereby producing the current collector.

[0089] Specifically, by selecting a thermoplastic elastomer layer as the support layer 1, the structural strength of the current collector is improved.

[0090] Specifically, the thermoplastic elastomer layer is at least one of a polyolefin-based thermoplastic elastomer layer, a polyurethane-based thermoplastic elastomer layer, and a polyamide-based thermoplastic elastomer layer. Therefore, the support layer 1 may be a composite membrane layer formed by physically pressing at least two of a polyolefin-based thermoplastic elastomer layer, a polyurethane-based thermoplastic elastomer layer, and a polyamide-based thermoplastic elastomer layer.

[0091] In one specific embodiment, the material of the support layer 1 is the same as the material of the separator of the lithium battery, which ensures that the current collector has a certain strength, meets the production needs of the battery, and ensures normal lithium ion permeability.

[0092] In step S102, the first conductive layer 2 is printed on the support layer 1 by a method such as screen printing, or by 3D printing, or by forming the first conductive layer 2 on the support layer 1 by deposition, or by magnetron sputtering.

[0093] In a specific embodiment, the first conductive layer 2 is Method 1) involves printing a mesh structure 20 on a support layer 1, then forming a metal mesh structure using at least one of physical vapor deposition, chemical vapor deposition, electrochemical deposition, and magnetron sputtering techniques, and then cleaning and drying the first conductive layer 2; Method 2) in which the first conductive layer 2 is directly printed or 3D printed on the support layer 1 and then dried; This may also be achieved by printing the mesh-like structure 20 on the support layer 1, then electroplating a metal layer onto the mesh-like structure 20 using electroplating technology, washing, and drying, and the electroplated metal layer increases the conductivity of the first conductive layer 2.

[0094] In this embodiment, the method for forming the first conductive layer on the support layer 1 is not particularly limited, as long as the first conductive layer 2 has a mesh structure 20 and meets the requirements for the thickness and mesh size of the first conductive layer 2. The third conductive layer 4 is formed on the support layer 1 using the same method as the method for forming the first conductive layer 2.

[0095] In the above step 103, the second conductive layer 3 may be formed on the first conductive layer 2 by thermal spraying or coating. If the second conductive layer 3 is formed by thermal spraying or coating, the thickness of the second conductive layer 3 is easily controlled.

[0096] In step 104, before drying the second conductive layer 3, the second conductive layer 3 may be roll-pressed to ensure the flatness of the second conductive layer 3. For example, the second conductive layer 3 on the surface of the first conductive layer 2 may be hardened by keeping the temperature at 100 to 150°C for 5 to 12 hours.

[0097] An embodiment of the present application provides a current collector. The current collector includes a support layer 1, a first conductive layer 2 with a mesh structure 20, and a second conductive layer 3 formed on the first conductive layer 2. The support layer 1 satisfies the strength requirements of the current collector, and the first conductive layer 2 and the second conductive layer 3 provide the current collector with electrical conductivity. In this embodiment, the first conductive layer 2 is formed on the support layer 1 with a mesh structure 20, reducing the weight per unit area of ​​the current collector and improving the energy density of the battery.

[0098] Specific examples are provided to verify the performance of the current collectors manufactured in specific embodiments and the performance of the batteries manufactured with the current collectors.

[0099] Example 1 1) A mesh is printed on the first surface 11 and the second surface 12 of a 5 μm thick polypropylene support layer (CMC and silica are mixed in a mass ratio of 1:9, and water is added to prepare a printing paste, which is then printed and dried). Aluminum is then deposited on the mesh-printed support layer using a physical vapor deposition technique, washed (during the washing process, the mesh printed on the support layer is dissolved and removed during washing), and dried to form a first conductive layer 2, with the deposited aluminum having a thickness of 5 μm and mesh holes that are square with a side length of 1 cm and spaced 1 mm apart. PVDF and carbon nanotubes are mixed in a mass ratio of 5:95, and NMP is added to prepare a uniform paste. This paste is then applied to both sides of the first conductive layer, forming a second conductive layer on the first conductive layer. The paste is then dried and rolled to obtain a porous current collector. This positive electrode current collector is designated as S1. Lithium iron phosphate, PVDF, carbon nanotubes, and carbon black were mixed in a mass ratio of 95:2:1.5:1.5, and NMP was added to prepare a positive electrode paste. This paste was then applied to the second conductive layer, dried, rolled, and cut to form a positive electrode plate. The areal density of the positive electrode plate was 200 g / m. 2 and 2) A mesh is printed on the first surface 11 and the second surface 12 of a 5 μm thick polypropylene support layer (CMC and silica are mixed in a mass ratio of 1:9, and water is added to prepare a printing paste, which is printed and then dried). Copper is deposited on the mesh-printed support layer 1 using a physical vapor deposition technique, followed by rinsing and drying, to form a first conductive layer 2, the deposited copper having a thickness of 5 μm, and the mesh holes are square with a side length of 1 cm and spaced 1 mm apart. PVDF and carbon nanotubes are mixed in a mass ratio of 5:95, and NMP is added to prepare a uniform paste. This paste is then applied to both sides of the first conductive layer, forming a second conductive layer on the first conductive layer. The paste is then dried and rolled to obtain a porous current collector. This negative electrode current collector is designated as S2. Graphite, CMC, carbon nanotubes, and carbon black were mixed in a ratio of 95:2:1.5:1.5, and NMP was added to prepare a negative electrode paste. This paste was then applied to the second conductive layer, dried, rolled, and cut to form a negative electrode plate. The areal density of the negative electrode plate was 90 g / m.2 and 3) The positive and negative plates were combined to produce a 6.1cm x 7.2cm pouch battery. 2mL of electrolyte was poured into the battery. After infiltration, formation, aging, and capacity screening, a 0.5C charge / discharge test was performed.

[0100] Comparative Example 1 Lithium iron phosphate, PVDF, carbon nanotubes, and carbon black were mixed in a mass ratio of 95:2:1.5:1.5, and NMP was added to prepare a positive electrode paste. This paste was then applied to a 10 μm-thick aluminum foil current collector D1, dried, rolled, and cut to form a positive electrode plate. The areal density of the positive electrode plate was 200 g / m. 2 and Graphite, CMC, carbon nanotubes, and carbon black were mixed in a mass ratio of 95:2:1.5:1.5, and water was added to prepare a paste. This paste was then applied to a 10 μm-thick copper foil current collector D2, dried, rolled, and cut to form a negative electrode plate. The areal density of the negative electrode plate was 90 g / m. 2 is.

[0101] The above electrode plates were combined to prepare a pouch battery measuring 6.1 cm x 7.2 cm. The amount of electrolyte injected was 2 mL. After infiltration, formation, aging, and capacity screening, a 0.5C charge-discharge test was carried out.

[0102] The current collectors S1, S2, D1, and D2 were each weighed to calculate the weight per unit area. Each battery was charged to 3.8 V at room temperature with a constant current of 0.5 C and discharged to 2 V with a constant current of 0.5 C, and the discharge capacity and charge capacity of the battery were recorded. [Table 1]

[0103] As can be seen from the comparison, the weight per unit area of ​​the current collector manufactured in the present application is 10-15% of the weight per unit area of ​​the current collector used in the prior art, significantly reducing the mass ratio of the current collector in the battery. Furthermore, the current collector has excellent performance, achieving more than 98% of the battery capacity of the conventional current collector.

[0104] The above embodiments have been described with an emphasis on the differences between each embodiment, and the different optimal features between each embodiment can be combined to form a more preferred embodiment, unless they are contradictory, and for the sake of brevity, the description will be omitted here.

[0105] Although some specific embodiments of the present application have been described in detail using examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present application. Those skilled in the art should understand that modifications to the above embodiments can be made without departing from the scope and spirit of the present application. The scope of the present application is limited by the appended claims. [Explanation of symbols]

[0106] 1 Support layer 11 First Surface 12 Second Surface 2. First conductive layer 3 Second conductive layer 4 Third conductive layer 20 mesh structure 201 mesh holes 202 Mesh Wall

Claims

1. A method for manufacturing a current collector, the current collector including a support layer (1), a first conductive layer (2), and a second conductive layer (3), The support layer (1) has a first surface (11) and a second surface (12) arranged opposite each other, The first conductive layer (2) has a mesh-like structure (20), the mesh-like structure (20) includes mesh holes (201) having an area ranging from 1 cm 2 to 10 cm 2 , the mesh holes (201) are surrounded by mesh walls (202), and the thickness of the mesh walls (202) ranges from 0.1 mm to 50 mm, and the first conductive layer (2) is disposed on the first surface (11) and / or the second surface (12) of the support layer (1); the second conductive layer (3) is disposed on a surface of the first conductive layer (2) away from the support layer (1); The method for producing the current collector includes: providing a support layer (1); forming a first conductive layer (2) on the first surface (11) and / or the second surface (12) of the support layer (1) using a printing technique so that a mesh-like structure (20) is disposed on the support layer (1); forming a second conductive layer (3) on the entire surface of the first conductive layer (2); and a step of drying the second conductive layer (3) to harden the second conductive layer (3) to produce a current collector.

2. 2. The method for producing a current collector according to claim 1, wherein the thickness of the first conductive layer (2) is in the range of 0.1 μm to 50 μm.

3. 2. The method for producing a current collector according to claim 1, wherein the thickness of the support layer (1) ranges from 0.1 μm to 20 μm.

4. 2. The method for producing a current collector according to claim 1, wherein the current collector has a thickness ranging from 1 μm to 100 μm.

5. 2. The method for producing a current collector according to claim 1, wherein the thickness of the second conductive layer (3) is in the range of 0.1 μm to 50 μm.

6. 2. The method for producing a current collector according to claim 1, wherein the support layer (1) is a thermoplastic elastomer layer having voids.

7. 2. The method for producing a current collector according to claim 1, further comprising a third conductive layer (4), the third conductive layer (4) having a mesh-like structure (20), the third conductive layer (4) being disposed on the first surface (11) or the second surface (12) of the support layer (1).

8. 8. The method for producing a current collector according to claim 7, wherein the first conductive layer (2) is disposed on a first surface (11) of the support layer (1) and the third conductive layer (4) is disposed on a second surface (12) of the support layer (1).

9. 8. The method for producing a current collector according to claim 7, wherein the first conductive layer (2) is disposed on a second surface (12) of the support layer (1) and the third conductive layer (4) is disposed on a first surface (11) of the support layer (1).

10. 8. The method for producing a current collector according to claim 7, wherein the second conductive layer (3) is disposed on a surface of the third conductive layer (4) remote from the support layer (1).

11. 8. The method for producing a current collector according to claim 7, wherein the first conductive layer (2) is a metal member, and the third conductive layer (4) is a metal member.

12. A method for manufacturing an electrode plate, comprising: the method for manufacturing a current collector according to any one of claims 1 to 11; and further comprising a step of forming an electrode paste layer on the second conductive layer (3).

Images