Electrode plate, its manufacturing method, and lithium battery

Abstract

An electrode plate, a manufacturing method thereof, and a lithium battery are provided. The electrode plate includes an electrode active material layer. The electrode active material layer includes a three-dimensional conductive network base, and an electrode active material and a binder supported on the three-dimensional conductive network base. The three-dimensional conductive network base and the electrode active material satisfy the following relationship: [0010] JPEG2025508528000013.jpg1386, where V is the actual volume of the 3D conductive network base, and its unit is cm 3 where m is the mass of the electrode active material in g, D is the particle diameter D50 of the electrode active material in μm, and ρ is the true density of the electrode active material in g / cm 3 where d is the thickness of a monolayer of carbon atoms, and the value of d is 0.334 nm.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to Chinese Patent Application No. 202210209397.X, entitled “ELECTRODE PLATE AND METHOD FOR PREPARATION THEREFOR, AND LITHIUM BATTERY,” filed on March 3, 2022, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of lithium batteries, and in particular to an electrode plate and its manufacturing method, and a lithium battery. [Background technology]

[0003] With the development of the new energy industry, the market demand for energy and power of lithium batteries is also increasing. According to literature reports, the industry improves the energy density and power of lithium batteries by increasing the surface density, compaction degree, and mass ratio of the electrode active material. However, in the traditional electrode plate production process, the industry generally adds an excess amount of conductive agent to ensure the conductivity of the electrode plate during charging and discharging of the battery. The excess amount of conductive agent inevitably causes the electrode plate to contain only a small amount of active material, which inhibits the function of the energy density of the battery. In addition, the distribution and morphology of the excess conductive agent in the electrode plate are both difficult to control. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of this, the present disclosure provides an electrode plate and a manufacturing method thereof, and a lithium battery. The electrode plate includes a three-dimensional conductive network base, and the conductive network in the electrode plate can be optimized by controlling the actual volume of the three-dimensional conductive network base and the electrode active material to satisfy a specific relationship, thereby improving the function of the capacity per gram, further promoting the function of the energy density of the battery, and improving the capacity retention rate of the battery. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, an electrode plate is provided. The electrode plate includes an electrode active material layer. The electrode active material layer includes a three-dimensional conductive network base, and an electrode active material and a binder supported on the three-dimensional conductive network base. The three-dimensional conductive network base and the electrode active material satisfy the following relationship:

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[0006] Optionally, D is in the range of 0.1 μm to 20 μm.

[0007] Optionally, for an electrode plate, the V corresponding to 100 g of electrode active material is 0.01 cm 3 ~20cm 3 is within the range.

[0008] Optionally, the lithium cobalt oxide has a true density of 5.1 g / cm 3 and the true density of the ternary material is 4.8 g / cm 3 The true density of lithium manganate is 4.2 g / cm 3 The true density of lithium iron phosphate is 3.6 g / cm 3 and the true density of graphite is 2.26 / cm 3 It is.

[0009] Optionally, the three-dimensional conductive network base is a current collector having a three-dimensional network structure.

[0010] Optionally, the electrode plate further comprises a current collector, and the three-dimensional conductive network base is disposed on at least one side of the current collector.

[0011] Optionally, the three-dimensional conductive network-based shape comprises a cage shape.

[0012] Optionally, at least a portion of the three-dimensional conductive network-based material comprises at least one of a conductive polymer, a metallic material, and a conductive carbon material.

[0013] Optionally, the electrode plate is a positive plate and the electrode active material comprises a positive electrode active material comprising at least one of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium cobalt oxide, lithium manganate, lithium nickel manganate, a layered lithium nickel cobalt manganate ternary material, a layered lithium nickel cobalt aluminate ternary material, and a nickel cobalt manganese aluminate quaternary material.

[0014] Optionally, the layered lithium nickel-cobalt-manganese oxide ternary material has the general structure Li 1+m Ni x Co y Mn 1-x-y O2, where x≧0.33, 0≦y≦0.4, and 0≦m≦0.1.

[0015] Optionally, the layered lithium nickel-cobalt-aluminate ternary material has the general structure Li 1+m Ni x Co y Al 1-x-y O2, where x≧0.33, 0≦y≦0.4, and 0≦m≦0.1.

[0016] Optionally, the nickel-cobalt-manganese-lithium aluminum oxide quaternary material has the general structure Li 1+m Ni xCo y Mn z Al 1-x-y-z O2, where x≧0.33, 0≦y≦0.4, 0≦z≦0.4, and 0≦m≦0.1.

[0017] Optionally, the electrode plate is a negative plate and the electrode active material comprises a negative electrode active material, the negative electrode active material comprising at least one of graphite, natural graphite, mesophase carbon microspheres, and silicon-carbon negative electrode material.

[0018] Correspondingly, according to a second aspect of the present disclosure, there is provided a method for manufacturing an electrode plate, the method comprising the steps of: Constructing a three-dimensional conductive network base, forming a mixed material containing an electrode active material and a binder on a three-dimensional conductive network base, and supporting the electrode active material on the three-dimensional conductive network base to obtain an electrode plate precursor; rolling the electrode plate precursor to obtain an electrode plate according to the first aspect of the present disclosure; Includes.

[0019] Optionally, forming a mixed material containing an electrode active material and a binder on the three-dimensional conductive network base includes: The method includes placing the three-dimensional conductive network base on a current collector, and then coating the three-dimensional conductive network base with a mixed material containing an electrode active material and a binder.

[0020] Optionally, rolling the electrode plate precursor comprises: The method includes placing the electrode plate precursor on a current collector and then rolling the electrode plate precursor.

[0021] Optionally, the method of constructing the three-dimensional conductive network base includes three-dimensional printing, powder metallurgy, electrodeposition, or etching a current collector.

[0022] Optionally, when the raw material used to manufacture the three-dimensional conductive network base is a non-conductive material, constructing the three-dimensional conductive network base further includes a conductive treatment.

[0023] Optionally, the conductive treatment comprises: Fabricating a three-dimensional conductive network base by three-dimensional printing or electrodeposition after the conductive agent is mixed into the raw material; or After the non-conductive three-dimensional network base is manufactured through three-dimensional printing or electrodeposition, a carbonization treatment is performed on the surface of the non-conductive three-dimensional network base or a conductive layer is formed on the non-conductive three-dimensional network base to obtain a three-dimensional conductive base. Includes.

[0024] Optionally, the forming method of forming the mixed material containing the electrode active material and the binder on the three-dimensional conductive network base includes coating, and the coating includes drip coating, brush coating, spray coating, dip coating, blade coating, or spin coating.

[0025] According to a third aspect of the present disclosure, there is provided a lithium battery comprising an electrode plate according to the first aspect of the present disclosure. [Brief description of the drawings]

[0026] [Figure 1A] FIG. 2 is a schematic structural diagram of a cross section of an electrode plate according to an embodiment of the present disclosure. [Figure 1B] FIG. 2 is a schematic structural diagram of a cross section of an electrode plate according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a schematic diagram of the three-dimensional conductive network-based structure manufactured in embodiment 1. [Diagram 3] 4 is a schematic flow chart of a method for manufacturing an electrode plate according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] One embodiment of the present disclosure provides an electrode plate. The electrode plate is a positive electrode plate or a negative electrode plate. The electrode plate includes an electrode active material layer. The electrode active material layer includes a three-dimensional conductive network base, and an electrode active material and a binder supported on the three-dimensional conductive network base. The three-dimensional conductive network base and the electrode active material satisfy the following relationship:

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[0028] In the present disclosure, first, a mathematical calculation model for the actual volume of the three-dimensional conductive network base is set, and starting from the function of the three-dimensional conductive network base, this base is a conductive network between electrode active materials, and all electrode active materials need to be connected to each other and shaped. Thus, each electrode active material is preset as a sphere having a diameter D. A plurality of spheres are densely arranged. In this case, it can be understood that the gaps between the densely arranged spheres are filled with a material for forming the three-dimensional conductive network base, and then the three-dimensional conductive network base material forms a three-dimensional conductive network connected to each other (i.e., the three-dimensional conductive network may be understood as a collection of prisms connected to each other to be combined, and this collection of prisms forms a hollow of a sphere or other shape). Alternatively, a preset three-dimensional network structure may be formed first, and then the electrode active material (preset as a sphere having a diameter D) is filled into the voids of the three-dimensional network structure. Therefore, the above mathematical calculation model can be regarded as a combination of a sphere having a diameter D as a minimum volume unit and a hollow regular hexahedron attached to the outer periphery of the sphere.

[0029] In the above equation, 6D 2 represents the surface area of ​​a hollow regular hexahedron (whose diameter is D) attached to the outer surface of a sphere, and the sphere has a diameter equal to the particle diameter D50 of the electrode active material. In this case, d × 6D 2 represents the minimum volume of the three-dimensional conductive network structure base used to form the aforementioned hollow regular hexahedron (i.e., the minimum volume of the three-dimensional conductive network structure base used in the minimum volume unit).

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[0030] When the actual volume V of the three-dimensional conductive network base is closer to the lower limit defined in the above-mentioned relationship, the amount of conductive agent used can be minimized, i.e., the proportion of active material in the electrode plate can be maximized, and the electrode plate has a good conductive path, so that the electrode plate has good rate performance and small internal resistance. When V is closer to the upper limit of the above-mentioned relationship, the precision required for parameter control in the production of the three-dimensional conductive network base can be reduced. The production efficiency of the electrode plate can be improved, and the proportion of active material in the electrode plate can be improved, thereby improving the function of capacity per gram, further promoting the function of energy density of the battery, and improving the capacity retention of the battery.

[0031] In addition, when the actual volume of the three-dimensional conductive network base satisfies the above-mentioned relationship, parameters such as the specific shape of the three-dimensional conductive network base, the size of the prism, and the connection method of the prism may be further designed according to the physicochemical properties (e.g., particle size and compaction degree) of the electrode active material used, in order to help pack the electrode active material particles in a directional manner (i.e., to limit the packing method and position of the active material particles). This can also be used to design the areal density and compaction degree of the electrode plate and cell, so that the active material of the electrode plate has a high areal density and high compaction degree, thereby improving the capacity per gram function, further promoting the energy density function of the battery, and improving the capacity retention rate of the battery.

[0032] In the present disclosure, the real volume of the three-dimensional conductive network base referred to above refers to the intrinsic volume of the three-dimensional conductive network base excluding its void volume. The real volume of the three-dimensional conductive network base is equal to the ratio of its mass to its true density.

[0033] In the present disclosure, the particle diameter D50 of the electrode active material refers to the average particle diameter of the electrode active material and has a unit of μm. Specific definitions of the particle diameter D50 include the following cases. (1) The particle diameter D50 may be a particle diameter corresponding to the case where the cumulative volume percentage of the powder electrode active material reaches 50%. (2) The particle diameter D50 may be a particle diameter corresponding to the case where the cumulative percentage of the powder electrode active material reaches 50%. (3) The particle diameter D50 may be a particle diameter corresponding to the case where the cumulative volume percentage of the electrode active material particles reaches 50%, or a particle diameter corresponding to the case where the cumulative percentage of the electrode active material particles reaches 50%, which is obtained by randomly sampling the powder electrode active material or electrode plate and observing the particle diameter state of the electrode active material particles by a scanning electron microscope (SEM) (the number of electrode active material particles in the sampled object is generally more than 500, preferably more than 1000).

[0034] When the electrode active material particles in the electrode plate are randomly sampled to obtain their particle diameter D50, the test method specifically includes the following steps: a) After disassembling a fully discharged battery to obtain an electrode plate, use argon ion to cut at any position in the dressing area to obtain a cross-sectional sample of the electrode plate. b) Place the cross-sectional sample of the electrode plate in the SEM for observation, adjust the voltage and magnification of the electron microscope according to the actual requirements, ensure that a sufficient number of particles in the sample can be clearly seen and photographed, and obtain an SEM image. c) Import the observed SEM image into grayscale debugging software (such as Geodict), and perform statistical processing on the particle diameter of the particles, or perform statistical processing on the particle diameter of the particles through artificial naked eye recognition. d) Cumulatively carry out 20 to 30 experiments (the statistical number of particles in each experiment is more than 500), and obtain the particle size distribution range and particle diameter D50 of the electrode active material particles in the electrode plate after performing statistical processing on the above results.

[0035] In some implementations of the present disclosure, D is in the range of 0.1 μm to 20 μm (i.e., the particle size D50 of the electrode active material is in the range of 0.1 μm to 20 μm). Controlling the particle size D50 of the electrode active material to be within the aforementioned range helps to suppress side reactions of the electrode active material during battery operation and helps to ensure that the electrode plate has a large degree of compaction, which in turn helps to ensure the energy density of the battery.

[0036] In some implementations of the present disclosure, the solid volume V of the three-dimensional conductive network base in the electrode plate corresponding to 100 g of electrode active material is less than 0.01 cm. 3 ~20cm 3For every 100 g of electrode active material, the corresponding actual volume V of the three-dimensional conductive network base is controlled within an appropriate range, i.e., the mass of the electrode active material supported on the three-dimensional conductive network base per unit volume is controlled. This is beneficial for ensuring the material mass ratio of the electrode active material in the electrode plate and the manufacturability of the electrode plate, and thus ensuring that the battery has an appropriate energy density, high battery capacity, excellent rate characteristics, and long service life.

[0037] The specific structure of the electrode plate in the embodiment of the present disclosure is described below, see Figures 1A and 1B.

[0038] In some implementations of the present disclosure, the three-dimensional conductive network base is a current collector having a three-dimensional network structure. In this case, the three-dimensional conductive network base may be obtained by etching the current collector. In this case, it can be understood that the current collector does not have a three-dimensional network structure throughout its thickness direction, but has a three-dimensional network structure on the side closer to the electrode active material layer, in order to facilitate the support of the electrode active material. Specifically, the electrode plate includes an unetched current collector and a three-dimensional conductive network base obtained after a part of the current collector is etched. In some specific embodiments, the current collector may include two parts in the thickness direction of the current collector. One part is a solid unetched current collector, and the other part includes a three-dimensional network structure obtained after the current collector is etched. In other words, the current collector includes a solid current collector substrate having a certain thickness and a current collector having a three-dimensional network structure (i.e., a three-dimensional conductive network base). In some other embodiments, the current collector may include three parts in the thickness direction of the current collector, i.e., a solid shape in the middle and a three-dimensional network structure on both sides. Specifically, the electrode plate includes an unetched current collector and two layers of a three-dimensional conductive network base obtained after a part of the current collector is etched. The two layers of the three-dimensional conductive network base are respectively disposed on both sides of the unetched current collector. It can be further understood that the shapes of the two layers of the three-dimensional conductive network base may be the same or different. An electrode active material is supported on each of all the three-dimensional conductive network bases. The electrode active materials supported on the two layers of the three-dimensional conductive network base may be the same or different.

[0039] In some other implementations of the present disclosure, the electrode plate further includes a current collector, and the three-dimensional conductive network base is disposed on at least one side of the current collector. The current collector may be a normal solid current collector in this case and does not have a three-dimensional network structure. Specifically, see FIG. 1A. In this case, the electrode plate 100 includes a current collector 10 and a three-dimensional conductive network base 11 disposed on a side of the current collector 10. Furthermore, the three-dimensional conductive network base may be disposed on one side of the current collector, or the three-dimensional conductive network base may be disposed on each of both sides of the current collector. Specifically, see FIG. 1B. In this case, the electrode plate 100 includes a current collector 10 and three-dimensional conductive network bases 11 and 12 disposed on both sides of the current collector 10, respectively. The shapes of the three-dimensional conductive network bases 11 and 12 may be the same or different. An electrode active material is supported on each of all the three-dimensional conductive network bases. The electrode active materials supported on the three-dimensional conductive network bases 11 and 12 may be the same or different. Only when the electrode active materials are supported on the three-dimensional conductive network base and the three-dimensional conductive network base is supported on the current collector can the normal operation of the battery be ensured.

[0040] In some implementations of the present disclosure, the shape of the three-dimensional conductive network base includes a cage shape. The cage structure is conducive to combining the three-dimensional conductive network base with the current collector and also to simplify the setting of parameters of the three-dimensional conductive network base in the longitudinal and lateral directions of the electrode plate in the design process. In some other implementations, the shape of the three-dimensional conductive network base may alternatively be a three-dimensional foam, an N-plane grid, a three-dimensional spherical grid, or some other three-dimensional mesh-like structure.

[0041] In one implementation of the present disclosure, at least a portion of the three-dimensional conductive network-based material includes at least one of a conductive polymer, a metal material, and a conductive carbon material. The metal material may be an elemental metal or a metal alloy. In some specific embodiments, the three-dimensional conductive network-based material may be a completely conductive material, specifically at least one of a conductive polymer, a metal material, and a conductive carbon material. In some other embodiments, a portion of the three-dimensional conductive network-based material may be a non-conductive material, specifically a non-conductive polymer, a ceramic material, and the like. In the aforementioned cases, a conductive agent may be mixed into the non-conductive material, or a conductive coating may be formed on the surface of the non-conductive material. The conductive agent may be a material such as carbon nanotubes, graphene, fullerene, graphene, conductive carbon black, or ketjen black. In particular, when the non-conductive material is a non-conductive polymer, a light carbonization process may be further performed on its surface, so that at least a portion of the material in the final three-dimensional conductive network base becomes a conductive material. Furthermore, at least the outer surface of the three-dimensional conductive network base is made conductive. Therefore, the three-dimensional conductive network base can be in full contact with the electrode active material, which allows an efficient conductive network to be formed on the electrode plate.

[0042] In one implementation of the present disclosure, the electrode active material includes a positive electrode active material or a negative electrode active material. It can be understood that when the aforementioned electrode plate is a positive electrode plate, the electrode active material is a positive electrode active material, and when the aforementioned electrode plate is a negative electrode plate, the electrode active material is a negative electrode active material. The positive electrode active material and the negative electrode active material are materials commonly used in the battery field.

[0043] The positive electrode active material includes, but is not limited to, at least one of lithium iron phosphate (LFP), lithium manganese phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium cobalt oxide, lithium manganate, lithium nickel manganate, layered lithium nickel cobalt manganate ternary material (NCM), layered lithium nickel cobalt aluminum oxide ternary material (NCA), and nickel cobalt manganese aluminum oxide quaternary material (NCMA). The negative electrode active material includes, but is not limited to, at least one of graphite, natural graphite, mesophase carbon microspheres, and silicon-carbon anode material. NCM stands for layered lithium nickel cobalt manganate ternary material, and in some implementations, Li 1+m Ni x Co y Mn 1-x-y O2 (x≧0.33, 0≦y≦0.4, and 0≦m≦0.1). NCA stands for layered nickel-cobalt-lithium aluminate ternary material, and in some implementations, Li 1+m Ni x Co y Al 1-x-y O2 (x≧0.33, 0≦y≦0.4, and 0≦m≦0.1). NCMA stands for nickel-cobalt-manganese-lithium aluminum oxide quaternary material, and in some implementations, Li 1+m Ni x Co y Mn z Al 1-x-y-z It has a general structural formula that can be represented as O2(x≧0.33, 0≦y≦0.4, 0≦z≦0.4, and 0≦m≦0.1).

[0044] In some specific embodiments of the present disclosure, the true density of the lithium cobalt oxide is 5.1 g / cm 3 and the true density of the aforementioned ternary material is 4.8 g / cm 3 The true density of the lithium manganate may be 4.2 g / cm 3 The true density of the lithium iron phosphate may be 3.6 g / cm3 The true density of the graphite may be 2.26 / cm 3 may be also possible.

[0045] Correspondingly, with reference to Figure 3, an embodiment of the present disclosure further provides a manufacturing method for an electrode plate. The manufacturing method includes the following steps:

[0046] S301: A three-dimensional conductive network base is constructed.

[0047] S302: A mixed material containing an electrode active material and a binder is formed on a three-dimensional conductive network base to support the electrode active material on the three-dimensional conductive network base, thereby obtaining an electrode plate precursor.

[0048] S303: The electrode plate precursor is rolled to obtain an electrode plate according to the present disclosure.

[0049] The present manufacturing method is highly controllable, easy to operate, and can be industrialized on a large scale.

[0050] In some implementations of the present disclosure, S302 includes applying a mixed material containing an electrode active material and a binder to the three-dimensional conductive network base after the three-dimensional conductive network base is placed on a current collector. In some other implementations, S303 includes rolling the electrode plate precursor after the electrode plate precursor is placed on a current collector.

[0051] In one implementation of the present disclosure, constructing the three-dimensional conductive network base in S301 includes, but is not limited to, performing three-dimensional printing, performing powder metallurgy, performing electrodeposition, or etching a current collector. The construction method may be adjusted according to the raw material used when the three-dimensional conductive network base is manufactured. For example, in some specific embodiments, when the raw material used for the three-dimensional conductive network base is a metal material, the three-dimensional conductive network base may be manufactured using a three-dimensional selective laser sintering method or a powder metallurgy method. In some embodiments, when the three-dimensional conductive network base is a current collector having a three-dimensional network structure, the three-dimensional conductive network base may be manufactured by etching a part of the current collector. When the raw material used for the three-dimensional conductive network base is a conductive polymer or a conductive inorganic carbon material, the three-dimensional conductive network base may be manufactured using a three-dimensional printing method or an electrodeposition method.

[0052] In some implementations, when the raw material used to manufacture the three-dimensional conductive network base is a non-conductive material (e.g., a non-conductive ceramic or a non-conductive polymer), the aforementioned method further includes a conductive treatment. The conductive treatment includes, but is not limited to, that before constructing the three-dimensional conductive network base, a conductive agent is mixed into the raw material, and then the three-dimensional conductive network base is directly manufactured using a three-dimensional printing method or an electrodeposition method, or that after the non-conductive three-dimensional network base is manufactured using a three-dimensional printing method or an electrodeposition method, a minor carbonization treatment is applied on the surface of the non-conductive three-dimensional network base or a conductive layer is formed on the surface of the non-conductive three-dimensional network base to obtain a three-dimensional conductive network base. The conductive layer is suitable for being disposed on any non-conductive three-dimensional network base, and the carbonization treatment is suitable for a non-conductive three-dimensional network base whose raw material is a polymer.

[0053] When the raw material used to manufacture the three-dimensional conductive network base is a conductive material (such as a conductive polymer, a conductive inorganic carbon material, or a metal material), the three-dimensional conductive network base can be directly constructed. Of course, the aforementioned conductive treatment can also be carried out on the three-dimensional conductive network base. The specific conductive treatment method can be determined according to the form of the material and the manufacturing method. The details will not be described again here.

[0054] In one implementation of the present disclosure, the forming method in S302 includes coating. The coating includes drip coating, brush coating, spray coating, dip coating, blade coating, or spin coating. The specific coating method can be determined based on the mixed material of the electrode active material and the binder. The mixed material may be liquid or solid. In some implementations of the present disclosure, the mixed material is a liquid mixed material containing a solvent, and the liquid mixed material may be formed on the three-dimensional conductive network base by a method such as drip coating, brush coating, spray coating, dip coating, blade coating, or spin coating. In some other implementations, the mixed material is a solid mixed material, and the solid mixed material may be formed on the three-dimensional conductive network base by a method such as powder spray coating.

[0055] An embodiment of the present disclosure further provides a lithium battery. The lithium battery includes an electrode plate according to the present disclosure. In some implementations, in the lithium battery, the positive electrode plate is an electrode plate provided in the present disclosure, and the negative electrode plate is a conventional electrode plate. In some implementations, in the lithium battery, the negative electrode plate is an electrode plate provided in the present disclosure, and the positive electrode plate is a conventional electrode plate. In some implementations, both the positive and negative electrodes in the lithium battery are electrode plates provided in the present disclosure.

[0056] The aforementioned batteries have high capacity per gram and excellent battery capacity retention, and the batteries have high energy density.

[0057] The following describes the technical solutions of the present disclosure in more detail with reference to specific embodiments.

[0058] EMBODIMENT 1 (1) Construction of a three-dimensional conductive network base: A three-dimensional conductive network base made of carbon fiber composite material was fabricated using three-dimensional printing technology (Figure 2). Specifically, carbon fiber was passed through a groove filled with polylactic acid (PLA) to obtain carbon fiber with a PLA-coated surface, and the carbon fiber with a PLA-coated surface was passed through a hole with a specific hole size, and the excess PLA on the surface of the carbon fiber was scraped off to obtain a filamentous carbon fiber composite material. Three-dimensional printing was performed using the aforementioned filamentous carbon fiber composite material. After curing, a three-dimensional conductive network base made of carbon fiber composite material was obtained, and then a light carbonization treatment was performed on its surface to obtain a three-dimensional conductive network base. The actual volume of the three-dimensional conductive network base was 1.13 cm 3 It is.

[0059] (2) Preparation of positive electrode plate: 100g LiNi 0.8 Co 0.1 Mn 0.1 (NCM811) (D50 of 1 μm and 4.8 g / cm 3 0.5g of PVDF5130 (true density) and 0.5g of binder were dissolved in N-methylpyrrolidone (NMP) and mixed uniformly to obtain the positive electrode active slurry. The three-dimensional conductive network base was placed on the aluminum foil as the positive electrode current collector, and the above positive electrode active slurry was coated on the three-dimensional conductive network base. After drying, the three-dimensional conductive network base was rolled to obtain the positive electrode plate.

[0060] (3) Preparation of negative electrode plate: 100g of graphite negative electrode active material, 1g of thickener, 1g of emulsion, and 2g of conductive carbon black are added to water in a specific order and mixed uniformly to obtain a negative electrode active slurry. The above-mentioned negative electrode active material is uniformly coated on the surface of the copper foil, which is the negative electrode current collector. After drying, it is pressed by a rolling machine to obtain a negative electrode plate.

[0061] (4) Battery manufacturing The positive electrode plate obtained in step (2), the negative electrode plate obtained in step (3), and a separator were alternately stacked to fabricate a laminated battery. The positive and negative electrode plates were alternately arranged, and adjacent positive and negative plates were separated by a separator to obtain a dry battery. The dry battery was placed in an aluminum-plastic film package injected with electrolyte, then sealed under vacuum, and kept at 60°C for 48 hours, after which it was pressed at 60°C, secondary encapsulated, evacuated, and capacity checked to obtain a laminated pouch full cell with a capacity of 2.2 Ah. The fabricated battery was designated as S1.

[0062] EMBODIMENT 2 The differences between embodiment 2 and embodiment 1 are as follows:

[0063] (1) Construction of the 3D conductive network base: The positive electrode current collector (aluminum foil) was etched using laser etching technology to obtain a 3D conductive network, and the actual volume of the 3D conductive network base in the current collector substrate was 1.13 cm 3 It was made to be like this.

[0064] (2) Preparation of positive electrode plate: 100g LiNi 0.8 Co 0.1 Mn 0.1 (NCM811) (D50 of 1 μm and 4.8 g / cm 3 0.5g of PVDF5130 (true density) and 0.5g of binder were dissolved in NMP and mixed uniformly to obtain the positive electrode active slurry. The positive electrode active slurry was uniformly coated on the three-dimensional conductive network base. After drying, the three-dimensional conductive network base was rolled to obtain the positive electrode plate.

[0065] The battery produced was designated as S2.

[0066] EMBODIMENT 3 The differences between embodiment 3 and embodiment 1 are as follows:

[0067] (1) Construction of a 3D conductive network base: Using 3D printing technology, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive polymer was printed into a 3D conductive network base, and the net volume of the 3D conductive network base was 1.13 cm. 3 It was made to be like this.

[0068] (2) Preparation of positive electrode plate: 100g LiNi 0.8 Co 0.1 Mn 0.1 (NCM811) (D50 of 1 μm and 4.8 g / cm 3 0.5g of PVDF5130 (true density) and 0.5g of binder were dissolved in NMP and mixed uniformly to obtain the positive electrode active slurry. The three-dimensional conductive network base was placed on the aluminum foil, and the above positive electrode active slurry was coated on the three-dimensional conductive network base. After drying, the three-dimensional conductive network base and the aluminum foil were rolled to obtain the positive electrode plate.

[0069] The battery produced was designated as S3.

[0070] EMBODIMENT 4 The differences between embodiment 4 and embodiment 1 are as follows:

[0071] (1) Construction of a three-dimensional conductive network base: Using three-dimensional printing technology, aluminum powder was used as the printing material to print a three-dimensional conductive network base on the aluminum foil positive current collector through selective laser sintering. The volume of the three-dimensional conductive network was 1.13 cm. 3 It was.

[0072] (2) Preparation of positive electrode plate: 100g LiNi 0.8 Co 0.1 Mn 0.1 (NCM811) (D50 of 1 μm and 4.8 g / cm 30.5g of PVDF5130 (true density) and 0.5g of binder were dissolved in NMP and mixed uniformly to obtain a positive electrode active slurry, and the positive electrode active slurry was coated on the three-dimensional conductive network base. After drying, the three-dimensional conductive network base and aluminum foil were rolled to obtain a positive electrode plate.

[0073] The battery produced was designated as S4.

[0074] EMBODIMENT 5 The manufacturing process is the same as that in embodiment 3, with the following differences: After the three-dimensional conductive network base is printed, the three-dimensional conductive network base is placed in a high-temperature oven, and a slight carbonization treatment is performed on the surface of the three-dimensional conductive network base at 200°C. The manufactured battery is designated as S5.

[0075] EMBODIMENT 6 The manufacturing process is similar to that in embodiment 3, with the difference being that carbon nanotubes were added to the raw material for three-dimensional printing, i.e., PEDOT:PSS conductive polymer, and the mass percentage of carbon nanotubes in the resulting mixture was 20%. The manufactured battery was designated as S6.

[0076] EMBODIMENT 7 The manufacturing process is the same as that in embodiment 3, with the difference being as follows: graphene is added to the raw material for three-dimensional printing, i.e., PEDOT:PSS conductive polymer, and the mass percentage of graphene in the resulting mixture is 20%. The manufactured battery is designated as S7.

[0077] Embodiments 8 to 19 According to the manufacturing method of embodiment 7, the positive electrode plates of embodiments 8 to 19 were manufactured. The changes in the parameters of the positive electrode plates in embodiments 8 to 19 are summarized in Table 1. Please refer to Table 1. The LFP has a D50 of 0.5 μm and a pore size of 3.6 g / cm 3The manufactured batteries are designated as S8 to S19, respectively.

[0078] EMBODIMENT 20 The negative plate of embodiment 20 also meets the limitations of the present disclosure. Specifically, using three-dimensional printing technology, a mixture of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive polymer and graphene (with the mass percentage of graphene in the mixture being 20%) is printed into a three-dimensional conductive network base, and 100 g of graphite negative active material (with a D50 of 15 μm and a pore size of 2.26 g / cm) is printed on the negative plate. 3 1 g of thickener, and 1 g of emulsion were added to water in a specific order and mixed uniformly to obtain a negative electrode active slurry. A three-dimensional conductive network base was placed on the copper foil as a negative electrode current collector, and the aforesaid three-dimensional conductive network base was coated with the aforesaid negative electrode active slurry. After drying, the three-dimensional conductive network base was rolled to obtain a negative electrode plate. The negative electrode plate and the positive electrode plate were assembled into a battery S20. It should be noted that the positive electrode plate of the battery S20 is the positive electrode plate manufactured in embodiment 7.

[0079] To highlight the beneficial effects of the embodiments of the present disclosure, the following comparative examples are set out.

[0080] Comparative Example 1 The difference from the seventh embodiment is as follows: The actual volume of the manufactured three-dimensional conductive network base is 0.06 cm 3 The battery produced was designated as DS1.

[0081] Comparative Example 2 The difference from the seventh embodiment is as follows: The actual volume of the manufactured three-dimensional conductive network base is 20 cm 3 The battery produced was designated as DS2.

[0082] Comparative Example 3 The differences from the first embodiment are as follows: 100g LiNi0.8 Co 0.1 Mn 0.1 (NCM811) (D50 of 1 μm and 4.8 g / cm 3 0.5 g of binder PVDF5130 was dissolved in NMP and mixed uniformly to obtain a positive electrode active slurry. 3 The above positive electrode active slurry was coated on a carbon fiber composite plate having a volume of 1000 μm and a carbonized surface, and placed on an aluminum foil. After drying, the carbon fiber composite plate was rolled to obtain a positive plate without a three-dimensional conductive network base. The fabricated battery was designated as DS3.

[0083] Comparative Example 4 The differences from the first embodiment are as follows: 100g LiNi 0.8 Co 0.1 Mn 0.1 (NCM811) (D50 of 1 μm and 4.8 g / cm 3 0.5g of PVDF5130 binder, and 2.486g of carbon fiber conductive agent (HV) were dissolved together in NMP and mixed uniformly to obtain a positive electrode active slurry. The above positive electrode active slurry was uniformly coated on an aluminum foil. After drying, the aluminum foil was rolled to obtain a three-dimensional conductive network-based positive plate. The fabricated battery was designated as DS4. [Table 1]

[0084] The electrochemical performance test of the electrode plates and batteries manufactured in the above embodiments and comparative examples includes the following steps.

[0085] (1) Longitudinal resistivity of electrode plate: The obtained positive electrode plate was tested for longitudinal resistivity using a longitudinal resistivity meter. The test pressure was set at 25 MPa, the pressurization time was 30 seconds, and the average value was taken after 10 points of each group of electrode plates were tested. The obtained data is summarized in Table 2.

[0086] (2) Ultimate compaction test of electrode plate: The pressure of the rolling mill was continuously increased, and the thickness of the electrode plate was tested using a micrometer until the thickness of the electrode plate could not be reduced any more, to obtain the ultimate compaction of the electrode plate. The obtained data are summarized in Table 3.

[0087] (3) Battery capacity test: The capacity test steps are as follows: Environmental temperature 25°C, 1C, 2.2Ah. 1) Charge: Charge to 4.25V / cell at 1 / 3C, constant current, and constant voltage, cut-off current of 0.05C, and hold for 30 minutes. 2) Discharge: Discharge to 2.5V / cell at 1 / 3C and constant current, and hold for 30 minutes. 3) Repeat the cycle three times, and record the third discharge capacity as the actual capacity of the battery. (Because the positive electrode active material used in embodiment 8 is LFP, the upper limit voltage is set to 3.8V and the lower limit voltage is set to 2.0V during the test.) The measurement results are summarized in Table 3.

[0088] (4) Battery cycle performance test: 1C, 2.2Ah. 1) Charge: Charge to 4.25V / cell at 1 / 3C, constant current, and constant voltage, with a cutoff current of 0.05C, and hold for 30 minutes. (2) Discharge: Discharge to 2.5V / cell at 1 / 3C and constant current, and hold for 30 minutes. 3) Repeat the cycle three times, and record the third discharge capacity as the actual capacity C0 of the battery. 4) Charge: Charge to 4.25V at 1C, constant current, and constant voltage, with a cutoff current of 0.05C, with the actual capacity C0 of the battery being 1C. 5) Hold for 30 minutes. (6) Discharge: Discharge to 2.5V at 1C and constant current, with the actual capacity C0 of the battery being 1C. 7) Hold for 30 minutes. 8) Repeat 4) to 7) for a total of 500 cycles. (Because the positive electrode active material used in embodiment 8 is LFP, the upper limit voltage is set to 3.8 V and the lower limit voltage is set to 2.0 V during the test.) The measurement results are summarized in Table 3. [Table 2] [Table 3]

[0089] From the data in Table 2, it can be seen that the positive electrode plate with a three-dimensional conductive network base (embodiments 1 to 19) has a longitudinal resistivity much lower than that of the positive electrode plate without a three-dimensional conductive network base (comparative example 3). In addition, when the actual volume of the three-dimensional conductive network base is within the limit value of the design rule, the longitudinal resistivity of the corresponding positive electrode plate (embodiments 1 to 19) is much lower than that of the positive electrode plate (comparative example 1) whose actual volume is less than the amount used in the design rule, while the positive electrode plate (comparative example 2) whose actual volume of the three-dimensional conductive network base exceeds the amount used in the design rule does not have a significant improvement in resistivity, and the mass proportion of the positive electrode active material in the electrode plate is inevitably reduced, which affects the battery performance. However, from the data on the ultimate compaction density of the positive plate, it can be seen that the ultimate compaction density of the positive plate having a three-dimensional conductive network base (embodiments 1 to 19 and comparative examples 1 and 2) is greater than the ultimate compaction density of the positive plate without a three-dimensional conductive network base (comparative example 3), but when the actual volume of the three-dimensional conductive network base exceeds the usage amount of the three-dimensional network design rules, the electrode plate compaction density of the corresponding positive plate decreases (comparative example 2).

[0090] From the data in Table 3, it can be seen that the battery with the electrode plate having the three-dimensional conductive network structure provided in the present disclosure has a relatively balanced performance in terms of the capacity per gram function and the capacity retention rate after cycling. When the actual volume of the three-dimensional conductive network structure exceeds the limit in the present disclosure, the capacity per gram is low (battery DS2). When the actual volume of the three-dimensional conductive network structure is below the limit in the present disclosure, a low capacity retention rate (battery DS1) is obtained. When the positive and negative plates of the battery are both electrode plates defined in the present disclosure (battery S20), the capacity retention rate of the battery S20 after 500 cycles is higher than that of the battery S7 in which the same positive plate is used, indicating that when the positive and negative plates of the battery are both electrode plates defined in the present disclosure, the capacity retention rate of the battery after cycling is better. Furthermore, from the data of batteries S1 to S20 in the embodiment and batteries DS1 to DS4 in the comparative example, it can be seen that electrode plates without a three-dimensional conductive network base have no advantage in terms of capacity per gram, and the capacity retention rate of the battery drops sharply.

[0091] The above description is an exemplary implementation of the present disclosure. It should be noted that a person skilled in the art may further make some improvements and modifications to the present disclosure without departing from the principle of the present disclosure. These improvements and modifications are also regarded as the protection scope of the present disclosure. [Explanation of symbols]

[0092] 100 electrode plate 10 Current collector 11 Three-dimensional conductive network-based 12 Three-dimensional conductive network-based

Claims

1. An electrode plate (100), comprising an electrode active material layer, the electrode active material layer comprising a three-dimensional conductive network base (11) and an electrode active material and a binder supported on the three-dimensional conductive network base (11), wherein the three-dimensional conductive network base (11) and the electrode active material satisfy the following relationship: [0010] where V is the actual volume of the three-dimensional conductive network base (11), and its unit is cm ３ where m is the mass of the electrode active material, the unit of which is g; D is the particle diameter D50 of the electrode active material, the unit of which is μm; and ρ is the true density of the electrode active material, the unit of which is g / cm ３ and d is the thickness of a monolayer of carbon atoms, and the value of d is 0.334 nm.

2. The electrode plate (100) of claim 1, wherein D is in the range of 0.1 μm to 20 μm.

3. In the electrode plate (100), V corresponding to 100 g of the electrode active material is 0.01 cm ３ ~20cm ３ The electrode plate (100) according to claim 1 or 2, wherein the thickness of the electrode plate (100) is within the range of

4. The electrode plate (100) according to any one of claims 1 to 3, wherein the three-dimensional conductive network base (11) is a current collector having a three-dimensional network structure.

5. The electrode plate (100) according to any one of claims 1 to 3, further comprising a current collector (10), and the three-dimensional conductive network base (11) is disposed on at least one side of the current collector (10).

6. 6. The electrode plate (100) according to any one of claims 1 to 5, wherein the shape of the three-dimensional conductive network base (11) comprises a cage shape.

7. 7. The electrode plate (100) of claim 1, wherein at least a portion of the material of the three-dimensional conductive network base (11) comprises at least one of a conductive polymer, a metallic material, and a conductive carbon material.

8. 8. The electrode plate (100) of any one of claims 1 to 7, wherein the electrode plate (100) is a positive plate and the electrode active material comprises a positive electrode active material, the positive electrode active material comprising at least one of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium cobalt oxide, lithium manganate, lithium nickel manganate, a layered lithium nickel cobalt manganate ternary material, a layered lithium nickel cobalt aluminum oxide ternary material, and a nickel cobalt manganese aluminum oxide quaternary material.

9. The general structural formula of the layered lithium nickel-cobalt-manganese oxide ternary material is Li １＋ｍ Ni ｘ Co ｙ Mn １－ｘ－ｙ O ２ 9. The electrode plate (100) of claim 8, wherein x > 0.33, 0 < y < 0.4, and 0 < m < 0.

1.

10. The general structural formula of the layered nickel-cobalt-lithium aluminum oxide ternary material is Li １＋ｍ Ni ｘ Co ｙ A １－ｘ－ｙ O ２ 10. The electrode plate (100) of claim 8 or 9, wherein x≧0.33, 0≦y≦0.4, and 0≦m≦0.

1.

11. The general structural formula of the nickel-cobalt-manganese-lithium aluminum oxide quaternary material is Li １＋ｍ Ni ｘ Co ｙ Mn ｚ A １－ｘ－ｙ－ｚ O ２ 11. The electrode plate (100) of claim 9 or 10, wherein x≧0.33, 0≦y≦0.4, 0≦z≦0.4, and 0≦m≦0.

1.

12. 8. The electrode plate (100) of any one of claims 1 to 7, wherein the electrode plate (100) is a negative plate, and the electrode active material comprises a negative electrode active material, the negative electrode active material comprising at least one of graphite, natural graphite, mesophase carbon microspheres, and silicon-carbon negative electrode material.

13. A method for manufacturing an electrode plate, comprising the steps of: Constructing a three-dimensional conductive network base (S301); A mixed material containing an electrode active material and a binder is formed on the three-dimensional conductive network base, and the electrode active material and the binder are supported on the three-dimensional conductive network base to obtain an electrode plate precursor (S302); rolling the electrode plate precursor to obtain the electrode plate according to any one of claims 1 to 12 (S303); A manufacturing method comprising:

14. forming the mixed material containing the electrode active material and the binder on the three-dimensional conductive network base, The manufacturing method according to claim 13, further comprising: applying the mixed material containing the electrode active material and the binder to the three-dimensional conductive network base after placing the three-dimensional conductive network base on a current collector.

15. The rolling of the electrode plate precursor includes: The method according to claim 13 , further comprising rolling the electrode plate precursor after placing the electrode plate precursor on a current collector.

16. Constructing the three-dimensional conductive network base comprises: The method of any one of claims 13 to 15, comprising performing three dimensional printing, performing powder metallurgy, performing electrodeposition, or etching the current collector.

17. The manufacturing method according to claim 16, wherein when the raw material used to manufacture the three-dimensional conductive network base is a non-conductive material, constructing the three-dimensional conductive network base further comprises subjecting it to a conductive treatment.

18. The conductive treatment is After a conductive agent is mixed into the raw material, the three-dimensional conductive network base is manufactured by the three-dimensional printing or the electrodeposition; or After the non-conductive three-dimensional network base is manufactured by the three-dimensional printing or the electrodeposition, a carbonization treatment is performed on the surface of the non-conductive three-dimensional network base or a conductive layer is formed on the non-conductive three-dimensional network base to obtain the three-dimensional conductive base. The method of claim 17, comprising:

19. The manufacturing method according to any one of claims 13 to 18, wherein the forming method of forming the mixed material containing the electrode active material and the binder on the three-dimensional conductive network base comprises coating, and the coating comprises drip coating, brush coating, spray coating, dip coating, blade coating, or spin coating.

20. A lithium battery comprising an electrode plate (100) according to any one of claims 1 to 12.

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