Dry-method pole piece, preparation method thereof and battery

Abstract

In order to solve the problem that an existing battery pole piece cannot be compatible with an active material with a small particle size (D50 < = 5 [mu] m) under a dry process, the invention provides a dry-method pole piece, a preparation method thereof and a battery, the dry-method pole piece comprises a current collector and an active substance layer compounded on the current collector, the active substance layer comprises an active substance, a conductive agent and an adhesive, the conductive agent comprises a one-dimensional conductive agent and a two-dimensional conductive agent, the mass percentage content of the adhesive in the active material layer is delta, and delta is less than or equal to 5%.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to a dry electrode sheet and its preparation method, and a battery. Background Technology

[0002] The manufacturing process of lithium-ion battery electrodes is generally a wet process, which uses an organic solvent (positive electrode) containing dissolved binder components or water (negative electrode) to mix the active materials and conductive agents required for the lithium-ion battery electrode into a homogeneous non-Newtonian fluid dispersion system, commonly known as a slurry. The slurry is then adhered to the surface of a metal foil through coating or other methods, followed by baking and rolling processes to complete the electrode. With the increasing demand for high electrode performance, dry processes have gradually become a focus of research and application. However, due to challenges in both formulation and process, no mature dry process has yet been widely adopted.

[0003] Current dry-process technologies primarily use fibrous polymers (such as polytetrafluoroethylene (PTFE) and its modified polymers) as binders, ternary materials (positive electrode), lithium cobalt oxide (positive electrode), lithium manganese oxide (positive electrode), or graphite (negative electrode) as active materials, and carbon black and graphene as conductive agents. In the formulation stage, common methods include air-jet spinning, mechanical shearing and drawing, or extrusion to achieve thorough mixing of the binder with the aforementioned conductive agents and active materials. From the perspective of the final electrode morphology, the dry-process electrode auxiliary layer produced by the above-described formulation and process can be understood as a mixed layer with a certain mechanical strength and flexibility, formed by a binder filament network that holds the conductive agent and active material together. Therefore, the density of the filament network (i.e., the amount of binder added) determines the high selectivity of this method for the particle size of the active material. However, in industrial lithium batteries, the tendency is to add as little binder as possible to obtain a higher proportion of active material and thus improve energy density. This means that the above method, with a low binder addition amount (≤5%), can only be applied to active materials with larger particle size (D50≥5μm), thus limiting the electrode based on smaller particle size active materials (D50≤5μm). Summary of the Invention

[0004] To address the problem that existing battery electrodes cannot be compatible with small-particle-size (D50≤3um) active materials under dry processing, this invention provides a dry electrode, its preparation method, and a battery.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] On one hand, the present invention provides a dry electrode sheet, comprising a current collector and an active material layer composited on the current collector, the active material layer comprising an active material, a conductive agent and a binder, the conductive agent comprising a one-dimensional conductive agent and a two-dimensional conductive agent, and the binder having a mass percentage content of δ in the active material layer, where δ≤5%.

[0007] Optionally, the conductive agent may further include other conductive agents, and the electrode satisfies the following conditions:

[0008] 0.5%≤a+b+c+δ≤6%, a≥1.2b≥c, a>0.25%, b>0.2%;

[0009] a represents the mass percentage of the one-dimensional conductive agent in the active material layer, in %;

[0010] b represents the mass percentage of the two-dimensional conductive agent in the active material layer, in %;

[0011] c represents the mass percentage of the other conductive agents in the active material layer, expressed as a percentage.

[0012] Optionally, the one-dimensional conductive agent includes one or more of conductive nanotubes and nanofibers;

[0013] The two-dimensional conductive agent includes one or more of graphene, sheet-like graphite microflakes, two-dimensional conductive metal-organic frameworks, and MXene;

[0014] The other conductive agents include one or more of carbon black, acetylene black, Ketjen black, graphene microspheres, three-dimensional conductive metal-organic frameworks, porous spherical carbon, porous silica, porous alumina, and porous titanium dioxide.

[0015] The adhesive includes one or more of polytetrafluoroethylene and its modified polymers, rubber, modified rubber, polyvinylidene fluoride, modified polyvinylidene fluoride, polyimide, modified polyimide, polypropylene, modified polypropylene, polyacrylic acid, modified polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, modified polyvinyl butyral, polyacrylonitrile, and modified polyacrylonitrile.

[0016] Optionally, the conductive nanotubes include one or more of multi-walled carbon nanotubes, single-walled carbon nanotubes, and silicon nitride nanotubes; the nanofibers include one or more of vapor-grown carbon nanofibers and metal nanowires.

[0017] Optionally, the particle size D50 of the active material is ≤5μm;

[0018] Alternatively, when the particle size D50 of the active material is greater than 5 μm, the binder does not include polytetrafluoroethylene.

[0019] Optionally, the tube length of the one-dimensional conductive agent is 10-300 μm, the aspect ratio of the one-dimensional conductive agent is 100-7143, and the wall thickness of the one-dimensional conductive agent is 1-10 nm; the sheet diameter of the two-dimensional conductive agent is 1-20 μm.

[0020] Optionally, the active material includes one or more of lithium cobalt oxide, ternary cathode material, lithium-rich compound, lithium iron phosphate, spinel lithium manganese oxide, high-voltage spinel nickel manganese oxide, sodium ion layered structure oxide, sodium ion polyanionic structure compound, sodium iron sulfate, Prussian blue / Prussian white sodium ion cathode material and zinc ion compound;

[0021] Alternatively, the active material may include one or more of the following: natural graphite, artificial graphite, hard carbon, soft carbon, silicon-carbon anode material, silicon suboxide and graphite mixed anode material, lithium titanate, tin oxide, and iron oxide.

[0022] On the other hand, the present invention provides a method for preparing a dry electrode as described in any of the above claims, comprising the following steps:

[0023] The conductive agent, the active substance, and the binder are mixed to obtain a mixture;

[0024] The mixture is processed and shaped to obtain an active material layer for a self-supporting electrode;

[0025] The active material layer and the current collector are rolled together to obtain an electrode.

[0026] Optionally, the conductive agent, the active material, and the binder are mixed to obtain a mixture, comprising the following steps:

[0027] The conductive agent, the active material, and the binder are mixed and then extruded through a screw.

[0028] Optionally, the conductive agent, the active material, and the binder are mixed to obtain a mixture, comprising the following steps:

[0029] The conductive agent and the active substance are premixed in dry powder to obtain a powder.

[0030] The pre-mixed dry powder is mixed with the binder.

[0031] On the other hand, the present invention provides a battery comprising a negative electrode, a separator, and a positive electrode, wherein the positive electrode or the negative electrode is a dry electrode as described in any of the above claims, or the positive electrode and / or the negative electrode is prepared by a dry electrode preparation method as described in any of the above claims.

[0032] In this invention, a physical network is constructed using one-dimensional conductive agents, two-dimensional conductive agents, and a binder to achieve the adhesion and aggregation of active material particles, thereby forming an active material layer. The addition of one-dimensional and two-dimensional conductive agents acts as a structural framework mesh, similar to the "steel" mesh in reinforced concrete. This allows small-particle-size (D50≤5μm) active materials to be captured by the framework mesh and form good adhesion and aggregation, even with a small amount of binder added (≤5%). Furthermore, because the one-dimensional and two-dimensional conductive agents form a well-connected one-dimensional + two-dimensional conductive network with a certain degree of spatial freedom, the electrode exhibits lower resistance and can adapt to the expansion and contraction of the active material during cycling, maintaining a good conductive network and thus achieving better cycling performance. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of a dry electrode preparation method according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic flowchart of a dry electrode preparation method provided in another embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram showing the capacity retention of the positive electrode sheets prepared by dry and wet methods in Example 1;

[0036] Figure 4 This is a schematic diagram showing the capacity retention of the positive electrode sheets prepared by dry and wet methods in Example 3;

[0037] Figure 5 This is a schematic diagram showing the capacity retention of the positive electrode prepared by the dry and wet methods in Example 4. Detailed Implementation

[0038] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] An embodiment of the present invention provides a dry electrode sheet, comprising a current collector and an active material layer composited on the current collector. The active material layer comprises an active material, a conductive agent, and a binder. The conductive agent comprises a one-dimensional conductive agent and a two-dimensional conductive agent. The mass percentage of the binder in the active material layer is δ, where δ≤5%. The particle size D50 of the active material is ≤5μm.

[0040] In this invention, a physical network is constructed using one-dimensional conductive agents, two-dimensional conductive agents, and a binder to achieve the adhesion and aggregation of active material particles, thereby forming an active material layer. The addition of one-dimensional and two-dimensional conductive agents acts as a structural framework mesh, similar to the "steel" mesh in reinforced concrete. This allows small-particle-size (D50≤5μm) active materials to be captured by the framework mesh and form good adhesion and aggregation, even with a small amount of binder added (≤5%). Furthermore, because the one-dimensional and two-dimensional conductive agents form a well-connected one-dimensional + two-dimensional conductive network with a certain degree of spatial freedom, the electrode exhibits lower resistance and can adapt to the expansion and contraction of the active material during cycling, maintaining a good conductive network and thus achieving better cycling performance.

[0041] In some embodiments, the conductive agent further includes other conductive agents, and the electrode satisfies the following conditions:

[0042] 0.5%≤a+b+c+δ≤6%, a≥1.2b≥c, a>0.25%, b>0.2%;

[0043] a represents the mass percentage of the one-dimensional conductive agent in the active material layer, in %;

[0044] b represents the mass percentage of the two-dimensional conductive agent in the active material layer, in %;

[0045] c represents the mass percentage of the other conductive agents in the active material layer, expressed as a percentage.

[0046] By adding other conductive agents, the conductive network can be formed into a point-line-plane structure, further reducing the electrode resistance. By limiting the content of one-dimensional conductive agents, two-dimensional conductive agents, other conductive agents, and binders, the active material can be better bonded and aggregated.

[0047] In some embodiments, the one-dimensional conductive agent includes one or more of conductive nanotubes and nanofibers;

[0048] The two-dimensional conductive agent includes one or more of graphene, sheet-like graphite microflakes, two-dimensional conductive metal-organic frameworks, and MXene;

[0049] The other conductive agents include one or more of carbon black, acetylene black, Ketjen black, graphene microspheres, three-dimensional conductive metal-organic frameworks, porous spherical carbon, porous silica, porous alumina, and porous titanium dioxide.

[0050] The adhesive comprises one or more of polytetrafluoroethylene (PTFE) and its modified polymers, rubber, modified rubber, polyvinylidene fluoride (PVDF), polyimide (PI), modified polyimide, polypropylene, modified polypropylene, polyacrylic acid (PAA), modified polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, modified polyvinyl butyral, polyacrylonitrile (PAN), and modified polyacrylonitrile. Specifically, the modified rubber includes, but is not limited to, HNBR (hydrogenated nitrile butadiene rubber) and NBR (nitrile butadiene rubber).

[0051] In some embodiments, the conductive nanotubes include one or more of multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), and silicon nitride nanotubes. The nanofibers include one or more of vapor-grown carbon nanofibers (VGCFs) and metal nanowires. Specifically, the metal nanowires include silver nanowires.

[0052] In some embodiments, the particle size D50 of the active substance is ≤5 μm;

[0053] Alternatively, when the particle size D50 of the active material is greater than 5 μm, the binder does not include polytetrafluoroethylene.

[0054] In some embodiments, the tube length of the one-dimensional conductive agent is 10-300 μm, the aspect ratio of the one-dimensional conductive agent is 100-7143, and the wall thickness of the one-dimensional conductive agent is 1-10 nm; the sheet diameter of the two-dimensional conductive agent is 1-20 μm. By limiting the aspect ratio of the one-dimensional conductive agent and the sheet diameter of the two-dimensional conductive agent, it is convenient for the one-dimensional and two-dimensional conductive agents to form a conductive network.

[0055] In some embodiments, when the active material is a positive electrode active material, the active material includes one or more of lithium cobalt oxide, ternary positive electrode materials, lithium-rich compounds, lithium iron phosphate, spinel lithium manganese oxide, high-voltage spinel nickel manganese oxide, sodium ion layered oxide, sodium ion polyanionic compound, sodium iron sulfate, Prussian blue / Prussian white sodium ion positive electrode materials, and zinc ion compounds. Specifically, sodium ion polyanionic compounds include, but are not limited to, sodium vanadium phosphate, sodium vanadium iron phosphate, sodium pyrophosphate, and sodium iron sulfate.

[0056] Specifically, ternary cathode materials include NCM materials, NCA materials, and NCMA quaternary materials, while zinc ion compounds are zinc ion cathode materials.

[0057] Alternatively, when the active material is a negative electrode active material, the active material includes one or more of the following: natural graphite, artificial graphite, hard carbon, soft carbon, silicon-carbon negative electrode material, silicon suboxide and graphite mixed negative electrode material, lithium titanate, tin oxide, and iron oxide.

[0058] On the other hand, such as Figure 1 and Figure 2 As shown, one embodiment of the present invention provides a method for preparing a dry electrode sheet as described in any of the above claims, comprising the following steps:

[0059] The conductive agent, the active substance, and the binder are mixed to obtain a mixture;

[0060] The mixture is processed and shaped to obtain an active material layer for a self-supporting electrode;

[0061] The active material layer and the current collector are rolled together to obtain an electrode.

[0062] Furthermore, when the binder is mixed with the conductive agent and active material, the binder can be pre-fiberized and / or pre-dispersed in advance; specifically, binder pre-fiberization involves subjecting the binder to high-speed airflow shearing, melt spinning, high-speed mechanical shearing, or other operations; and / or, binder pre-dispersion refers to dispersing the binder in a specific medium.

[0063] Furthermore, the mixture is processed into an active material layer for a self-supporting electrode by means of multi-stage heated rolling or direct screw extrusion.

[0064] like Figure 1 As shown, in some embodiments, the conductive agent, the active material, and the binder are mixed to obtain a mixture, including the following steps:

[0065] The conductive agent, the active material, and the binder are mixed and then extruded through a screw.

[0066] like Figure 2 As shown, in some embodiments, the conductive agent, the active material, and the binder are mixed to obtain a mixture, including the following steps:

[0067] The conductive agent and the active substance are premixed in dry powder to obtain a powder.

[0068] The pre-mixed dry powder is mixed with the binder. The mixing method includes, but is not limited to, kneading, air mixing or fiberization, to ensure that the conductive agent, the active material and the binder are mixed evenly.

[0069] On the other hand, the present invention provides a battery comprising a negative electrode, a separator, and a positive electrode, wherein the positive electrode or the negative electrode is a dry electrode as described in any of the above claims, or the positive electrode and / or the negative electrode is prepared by a dry electrode preparation method as described in any of the above claims.

[0070] The present invention will be further illustrated by the following examples.

[0071] Example 1

[0072] This embodiment illustrates the electrode and battery disclosed in this invention, and includes the following operational steps:

[0073] Preparation of positive electrode

[0074] The binder is PTFE, and the one-dimensional conductive agent is MWCNT with a tube length of 20 μm and an aspect ratio of 500. The two-dimensional conductive agent is graphene material with a sheet diameter of 4 μm. The active material is lithium iron phosphate material with a particle size D. 50 =0.8μm; The mass ratio of binder: one-dimensional conductive agent: two-dimensional conductive agent: active material is 2.9:1.7:0.2:95.2.

[0075] The binder is pre-fiberized, and the conductive agent and the active material are pre-mixed in dry powder form to obtain a powder.

[0076] The dry powder premixed material is kneaded or air-mixed with the pre-fiberized binder.

[0077] The mixture is subjected to multi-stage differential speed rolling to form an active material layer for a self-supporting electrode;

[0078] The active material layer and the current collector are rolled together and dried to obtain electrode S1.

[0079] The above-mentioned binder, one-dimensional conductive agent, two-dimensional conductive agent, active material and solvent are thoroughly mixed to form a slurry, which is then coated on the current collector, dried and rolled to obtain the electrode S1'.

[0080] Production of negative electrode plates:

[0081] The negative electrode active material graphite, conductive agent acetylene black, binder styrene-butadiene rubber, and thickener sodium carboxymethyl cellulose were thoroughly mixed in an appropriate amount of deionized water solvent at a mass ratio of 94.5:1.5:1.5:1.5 to form a uniform negative electrode slurry. This slurry was coated onto a negative electrode current collector Cu foil, dried, and cold-pressed to obtain the negative electrode sheet.

[0082] The manufacturing process of lithium-ion batteries:

[0083] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. Then, the electrode is wound up to the bare cell. The bare cell is placed in an outer packaging bag, and the prepared electrolyte is injected into the dried battery. After vacuum sealing, settling, formation, and shaping, the battery manufacturing process is complete.

[0084] Example 2

[0085] This embodiment is used to illustrate the electrode and battery disclosed in this invention, including most of the operation steps in the embodiment, the difference being: the binder is pre-fiberized, and the conductive agent, the active material and the pre-fiberized binder are mixed and then extruded by a screw.

[0086] The mixture is heated and rolled in multiple stages to obtain an active material layer for a self-supporting electrode;

[0087] The active material layer and the current collector are rolled together and dried to obtain electrode S2.

[0088] The above-mentioned binder, one-dimensional conductive agent, two-dimensional conductive agent, active material and solvent are thoroughly mixed to form a slurry, which is then coated on the current collector, dried and rolled to obtain the electrode S2'.

[0089] Example 3-18

[0090] The examples illustrate the electrode and battery disclosed in this invention, including most of the operational steps in Example 1, except that the formulation in Table 1 is used. The conductive agent has a tube length of 1 μm after dispersion.

[0091] Comparative Examples 1-2

[0092] The comparative examples are used to illustrate the electrode and battery disclosed in this invention, including most of the operating steps in Example 1, except that the formulation in Table 1 is used.

[0093] Table 1

[0094]

[0095]

[0096] Performance testing

[0097] I. The following performance tests were performed on the batteries obtained in the above embodiments and comparative examples:

[0098] Cycle stability test: After being placed at 45±2℃ for 2 hours, the battery was subjected to standard charge-discharge cycles at a cycle rate of 1C and a charging voltage of 3.0-4.45V. The capacity retention rate of the battery after the cycles was calculated. The calculation formula is as follows:

[0099] Capacity retention rate after nth cycle (%) = (Discharge capacity after nth cycle) / (Discharge capacity after first cycle) * 100%

[0100] The test results are shown in Table 2. Figures 3-5 As shown in Table 2, the test data are for batteries assembled from positive electrode sheets prepared by the dry method.

[0101] Table 2

[0102] Capacity retention rate (%) after 500 cycles at 45°C Example 1 93.36 Example 2 92.18 Example 3 94.3 Example 4 93.85 Example 5 93.5 Example 6 95.23 Example 7 88.7 Example 8 96.11 Example 9 93.1 Example 10 95.5 Example 11 96.06 Example 12 95.89 Example 13 91.8 Comparative Example 1 92.96 Comparative Example 2 92.36

[0103] Depend on Figures 3-5 It can be seen that, for the same active material layer, the capacity retention rate of the electrode prepared by the dry method is higher than that of the electrode prepared by the wet method.

[0104] The test results of Example 1 and Comparative Examples 1-2 show that only when both one-dimensional and two-dimensional conductive agents are present can small-particle-size (D50≤3μm) active materials be well bonded and aggregated with the addition of a small amount of binder. The test results of Examples 1 and 5-11 show that changing the content and specifications of the one-dimensional and two-dimensional conductive agents significantly alters the capacity retention rate.

[0105] The test results of Examples 1-3 show that the capacity retention rate of the battery can be improved by adjusting the content of the binder.

[0106] The test results of Examples 1 and 4 show that the capacity retention rate of the battery is improved by adding other conductive agents.

[0107] The test results from Examples 1 and 5-11 show that when the contents of binder, one-dimensional conductive agent, two-dimensional conductive agent, and other conductive agents satisfy 0.5% ≤ a + b + c + δ ≤ 6%, a ≥ 1.2b ≥ c, a > 0.25%, and b > 0.2%, the capacity retention rate is significantly improved, and the battery achieves better cycle performance. Although in Example 8, a + b + c + δ is greater than 6% and the capacity retention rate is high, the increase in the conductive agent content leads to a decrease in the content of active material in the electrode, affecting the energy density of the battery. In Examples 11 and 12, a < 1.2b, which is not conducive to constructing a "reinforcing steel" mesh similar to that in reinforced concrete, affecting the mechanical properties of the electrode.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dry-processed electrode, characterized in that, The device includes a current collector and an active material layer composited on the current collector. The active material layer includes an active material, a conductive agent, and a binder. The conductive agent includes a one-dimensional conductive agent and a two-dimensional conductive agent. The mass percentage of the binder in the active material layer is δ, where δ≤5%.

2. The dry-process electrode sheet according to claim 1, characterized in that, The conductive agent also includes other conductive agents, and the electrode satisfies the following conditions: 0.5%≤a+b+c+δ≤6%, a≥1.2b≥c, a>0.25%, b>0.2%; a represents the mass percentage of the one-dimensional conductive agent in the active material layer, in %; b represents the mass percentage of the two-dimensional conductive agent in the active material layer, in %; c represents the mass percentage of the other conductive agents in the active material layer, expressed as a percentage.

3. The dry-process electrode sheet according to claim 2, characterized in that, The one-dimensional conductive agent includes one or more of conductive nanotubes and nanofibers; The two-dimensional conductive agent includes one or more of graphene, sheet-like graphite microflakes, two-dimensional conductive metal-organic frameworks, and MXene; The other conductive agents include one or more of carbon black, acetylene black, Ketjen black, graphene microspheres, three-dimensional conductive metal-organic frameworks, porous spherical carbon, porous silica, porous alumina, and porous titanium dioxide. The adhesive includes one or more of polytetrafluoroethylene and its modified polymers, rubber, modified rubber, polyvinylidene fluoride, modified polyvinylidene fluoride, polyimide, modified polyimide, polypropylene, modified polypropylene, polyacrylic acid, modified polyacrylic acid, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl butyral, modified polyvinyl butyral, polyacrylonitrile, and modified polyacrylonitrile.

4. The dry-process electrode sheet according to claim 1, characterized in that, The particle size D50 of the active substance is ≤5μm; Alternatively, when the particle size D50 of the active material is greater than 5 μm, the binder does not include polytetrafluoroethylene.

5. The dry-process electrode sheet according to claim 1, characterized in that, The tube length of the one-dimensional conductive agent is 10-300 μm, the aspect ratio of the one-dimensional conductive agent is 100-7143, and the wall thickness of the one-dimensional conductive agent is 1-10 nm; the sheet diameter of the two-dimensional conductive agent is 1-20 μm.

6. The dry-process electrode sheet according to claim 1, characterized in that, The active material includes one or more of the following: lithium cobalt oxide, ternary cathode material, lithium-rich compound, lithium iron phosphate, spinel lithium manganese oxide, high-voltage spinel nickel manganese oxide, sodium ion layered structure oxide, sodium ion polyanionic structure compound, sodium iron sulfate, Prussian blue / Prussian white sodium ion cathode material, and zinc ion compound. Alternatively, the active material may include one or more of the following: natural graphite, artificial graphite, hard carbon, soft carbon, silicon-carbon anode material, silicon suboxide and graphite mixed anode material, lithium titanate, tin oxide, and iron oxide.

7. A method for preparing a dry electrode sheet as described in any one of claims 1-7, characterized in that, Includes the following steps: The conductive agent, the active substance, and the binder are mixed to obtain a mixture; The mixture is processed and shaped to obtain an active material layer for a self-supporting electrode; The active material layer and the current collector are rolled together to obtain a dry electrode sheet.

8. The method for preparing dry-process electrode sheets according to claim 7, characterized in that, The conductive agent, the active material, and the binder are mixed to obtain a mixture, comprising the following steps: The conductive agent, the active material, and the binder are mixed and then extruded through a screw.

9. The method for preparing dry-process electrode sheets according to claim 7, characterized in that, The conductive agent, the active material, and the binder are mixed to obtain a mixture, comprising the following steps: The conductive agent and the active substance are premixed in dry powder to obtain a powder. The pre-mixed dry powder is mixed with the binder.

10. A battery, characterized in that, It includes a negative electrode, a separator, and a positive electrode, wherein the positive electrode or the negative electrode is a dry electrode as described in any one of claims 1-6, or the positive electrode and / or the negative electrode is prepared by the dry electrode preparation method as described in any one of claims 7-9.

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