A quasi-dry method for preparing an electrode sheet, an electrode sheet, and a lithium ion battery

Abstract

The application provides a quasi-dry method for preparing an electrode sheet, a battery electrode sheet and a lithium ion battery, and relates to the field of lithium ion battery preparation. The quasi-dry method for preparing an electrode sheet comprises the following steps: mixing an active material, a conductive agent, a solvent and a binder to obtain a composite; drying the composite after arranging the composite on a current collector; and rolling to obtain an electrode sheet; wherein the composite is a paste-like composite; and the solid content of the composite is 76-95%. Compared with the prior art, the method for preparing a battery electrode sheet provided by the application effectively avoids the problems of easy delamination and large interface resistance of the pure dry method process, and avoids the defects of difficulty in densification due to drying shrinkage of a thick electrode in a wet method.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery preparation, and in particular to a quasi-dry electrode preparation method, battery electrodes, and lithium-ion batteries. Background Technology

[0002] With the increasing demand for high energy density, high safety, and low-cost manufacturing of power batteries and energy storage batteries, electrode manufacturing processes have become a key focus of industry research and development. Currently, the mainstream electrode preparation methods mainly include two processes: wet coating and dry electrode fabrication.

[0003] The wet coating process typically involves dispersing active materials, conductive agents, binders, and other components in a solvent (such as N-methylpyrrolidone) to form a slurry, which is then coated onto the surface of the current collector and subsequently dried and rolled to form an electrode. While this technology is mature, it suffers from drawbacks such as high solvent recovery costs, environmental pollution, high drying energy consumption, and limitations on electrode thickness.

[0004] Dry electrode processing involves directly mixing active materials, conductive agents, and fibrous binders (such as polytetrafluoroethylene), followed by hot rolling to form a film after fiberization, and then laminating it with a current collector. This process eliminates the need for solvents and can achieve thick electrode fabrication, but it is more difficult to control and prone to problems such as internal electrode delamination, insufficient bonding strength, and poor electrolyte wettability. Furthermore, it is highly dependent on material properties (such as binder type, particle size, and morphology of active materials), resulting in a narrow process window.

[0005] In summary, existing dry processes suffer from drawbacks such as insufficient interlayer bonding, easy delamination, and high interfacial resistance between the electrode and current collector, affecting rate performance. Traditional wet processes, on the other hand, consume large amounts of solvent, leading to high drying energy consumption, increased costs, and poor environmental performance. Therefore, there is an urgent need to develop a novel electrode manufacturing method that balances process controllability, interfacial bonding, and environmental friendliness. Summary of the Invention

[0006] The purpose of this application is to provide a quasi-dry electrode preparation method, a battery electrode, and a lithium-ion battery to solve the above-mentioned problems.

[0007] To achieve the above objectives, this application adopts the following technical solution: This application provides a quasi-dry electrode preparation method, comprising: The active material, conductive agent, solvent, and binder are mixed to obtain a composite material; The composite was placed on a current collector and then dried; after rolling, an electrode sheet was obtained. The complex is a paste-like complex; the solid content of the complex is 76%-95%.

[0008] Optionally, the composite material comprises, based on 100% of the mass of the solid raw materials, 95% active material, 3% conductive agent, and 2% binder.

[0009] Optionally, the active material includes a positive electrode active material and a negative electrode active material; The positive electrode active material includes lithium iron phosphate; The negative electrode active material includes at least one of graphite, hard carbon, and silicon carbon.

[0010] Optionally, the conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene, and carbon fiber.

[0011] Optionally, the solvent includes at least one of N-methylpyrrolidone, water, dimethyl sulfoxide, dimethylformamide, acetone, ethanol, and isopropanol.

[0012] Optionally, the adhesive includes at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylonitrile, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide.

[0013] Optionally, the current collector includes a positive current collector and a negative current collector; The positive current collector includes one of the following: bright aluminum foil, etched aluminum foil, carbon-coated aluminum foil, and porous aluminum foil; The negative electrode current collector includes copper foil or carbon-coated copper foil.

[0014] Optionally, the adhesive may further include copolymers or modifiers of at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylonitrile, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide.

[0015] Optionally, the mass of the solvent is 0.5-20% of the mass of the positive electrode active material.

[0016] Optionally, the solid content of the adhesive is 1-20%.

[0017] Optionally, the rolling temperature is 20-150℃ and the roller diameter is 100-600mm.

[0018] Optionally, the electrode comprises a positive electrode and a negative electrode.

[0019] This application also provides a battery electrode, which is prepared using the aforementioned quasi-dry electrode preparation method.

[0020] Optionally, the thickness of the battery electrode is 50-200 μm.

[0021] Optionally, the compaction density of the battery electrode is 2.45-2.54 g / cm³.3 .

[0022] Thirdly, this application also provides a lithium-ion battery, including the battery electrode.

[0023] Compared with the prior art, the beneficial effects of this application include: This application provides a quasi-dry electrode preparation method. By introducing a small amount of solvent or binder solution, an initial liquid-phase bridge is formed within the material, improving the interfacial wetting between the active material, conductive agent, and binder. Furthermore, the physical interlocking and interfacial bonding between the film layer and the current collector are enhanced during calendering or transfer printing through the combination of a current collector and a semi-dry composite. The prepared battery electrode exhibits higher bonding strength and electrode integrity, effectively avoiding the problems of easy delamination and high interfacial resistance inherent in pure dry processes. Moreover, the "semi-dry or paste-like composite" makes the material plastic rather than a flowable slurry, avoiding problems such as slurry settling and edge effects in traditional wet coating processes. This makes it easier to calender, transfer, or pre-form, suitable for high-speed continuous production. It ensures the material is in an easily processable semi-dry state, neither too dry for forming nor too wet requiring lengthy drying, guaranteeing the effective dispersion and function of the binder in a small amount of solvent. This results in good process stability and controllability in different systems. In addition, by controlling the morphology of the composite, the drying load is significantly reduced, eliminating the need for a large solvent recovery system, thus saving energy and being environmentally friendly. Meanwhile, due to the low total solvent volume and short drying time, thick electrodes can be prepared, avoiding the cracking problem caused by uneven drying shrinkage in wet-process thick electrodes; and fully utilizing the volumetric capacity potential of the material. Compared with existing technologies, it effectively avoids the problems of easy delamination and high interfacial resistance in pure dry processes, while also avoiding the defects of wet-process thick electrodes that are difficult to densify due to drying shrinkage. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0025] Figure 1 Here is a photograph of the positive electrode sheet prepared in Example 3; Figure 2 The image shows a physical sample of the thick electrode sheet prepared using the traditional wet process, which serves as Comparative Example 4. Detailed Implementation

[0026] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0027] The conjunction "composed of" excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of" appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0028] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0029] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0030] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0031] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0032] To better explain the technical solution provided in this application, the technical solution provided in this application will be described in general before the specific implementation.

[0033] In a first aspect, this application provides a quasi-dry electrode preparation method, comprising: The active material, conductive agent, solvent, and binder are mixed to obtain a composite material; The composite was placed on a current collector and then dried; after rolling, an electrode sheet was obtained. The complex is a paste-like complex; the solid content of the complex is 76%-95%.

[0034] The composite material provided in this application is in a paste or semi-dry state. Compared to the loose powder produced by the pure dry method, the introduction of a small amount of solvent or binder solution creates an initial liquid-phase bridge within the material, improving the interfacial wetting between the active material, conductive agent, and binder. Combined with the semi-dry composite material, it enhances the physical interlocking and interfacial bonding between the film layer and the current collector during calendering or transfer printing. The resulting battery electrode exhibits higher bonding strength and electrode integrity, effectively avoiding the problems of easy delamination and high interfacial resistance inherent in the pure dry process.

[0035] In one optional embodiment, the composite comprises, based on the mass of 100% of the solid raw materials, 95% active material, 3% conductive agent, 2% binder, with the remaining solvent added according to the solid content.

[0036] In one optional embodiment, the active material includes a positive electrode active material and a negative electrode active material; The positive electrode active material includes lithium iron phosphate; The negative electrode active material includes at least one of graphite, hard carbon, and silicon carbon.

[0037] In one optional embodiment, the conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene, and carbon fiber.

[0038] In an optional embodiment, the solvent includes at least one selected from N-methylpyrrolidone, water, dimethyl sulfoxide, dimethylformamide, acetone, ethanol, and isopropanol.

[0039] In one alternative embodiment, the adhesive comprises at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylonitrile, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide.

[0040] In an optional implementation, the current collector includes a positive current collector and a negative current collector; The positive current collector includes one of the following: bright aluminum foil, etched aluminum foil, carbon-coated aluminum foil, and porous aluminum foil; The negative electrode current collector includes copper foil or carbon-coated copper foil.

[0041] In an optional embodiment, the adhesive further includes a copolymer or modifier of at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylonitrile, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide.

[0042] In one optional embodiment, the mass of the solvent is 0.5-20% of the mass of the positive electrode active material.

[0043] Optionally, the mass of the solvent can be 0.5%, 5%, 15%, 20% of the mass of the positive electrode active material, or any value between 0.5% and 20%.

[0044] This application employs a "semi-dry or paste-like composite material," where the material is in a plastic state rather than a flowable slurry. This avoids problems such as slurry settling and edge effects in traditional wet coating processes, making it easier to calender, transfer, or pre-form, and suitable for high-speed continuous production. The solvent dosage is limited to 0.5%-20% of the active material's mass, ensuring the material is in a semi-dry state that is easy to process—neither too dry for molding nor too wet requiring a lengthy drying process.

[0045] In one optional embodiment, the adhesive has a solids content of 1-20%.

[0046] Optionally, the solid content of the adhesive can be 1%, 5%, 10%, 15%, 20%, or any value between 1% and 20%.

[0047] The binder has a solid content of 1%-20%, which ensures the effective dispersion and function of the binder in a small amount of solvent.

[0048] In one optional embodiment, the rolling temperature is 20-150°C and the roller diameter is 100-600 mm.

[0049] Optionally, the rolling temperature can be 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, or any value between 20℃ and 150℃; the roll diameter can be 100mm, 200mm, 300mm, 400mm, 500mm, or 600mm, or any value between 100mm and 600mm.

[0050] The method provided in this application utilizes the low initial porosity and tight material bonding of the semi-dry composite after mixing, providing a favorable initial packing state for subsequent rolling. Combined with limitations on rolling temperature and roller diameter, high compaction density can be achieved with a lower number of compression cycles. This method allows the electrode to reach the theoretical high compaction density range of the material, more fully utilizing its volumetric capacity potential, while avoiding the shortcomings of wet-process thick electrodes that are difficult to densify due to drying shrinkage.

[0051] In one alternative implementation, the electrode includes a positive electrode and a negative electrode.

[0052] The method provided in this application can prepare positive and negative electrode sheets, and the process has good process stability and controllability in different systems.

[0053] This application also provides a battery electrode, which is prepared using the aforementioned quasi-dry electrode preparation method.

[0054] In one optional embodiment, the thickness of the battery electrode is 50-200 μm.

[0055] Optionally, the thickness of the battery electrode can be 50μm, 100μm, 150μm, 200μm, or any value between 50 and 200μm.

[0056] In one optional embodiment, the compaction density of the battery electrode is 2.45-2.54 g / cm³. 3 .

[0057] Optionally, the compaction density of the battery electrode can be 2.45 g / cm³. 3 2.50 g / cm 3 2.55 g / cm 3 Or 2.45-2.55 g / cm³ 3 Any value between.

[0058] Thirdly, this application also provides a lithium-ion battery, including the battery electrode.

[0059] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0060] Example 1 This embodiment provides a positive electrode plate: The compacted density is approximately 2.52 g / cm³.3 The thickness of the electrode sheet is 163 μm.

[0061] This embodiment provides a quasi-dry preparation method for the above-mentioned positive electrode sheet, and the specific steps are as follows: 2865g of lithium iron phosphate (LiFePO4) positive electrode active material, 75g of conductive carbon black (SP), and 400g of polyvinylidene fluoride (PVDF) with a solid content of 15% were mixed. The amount of NMP solvent added was controlled to be 10% of the mass of the positive electrode active material. The mixed material was a uniform paste.

[0062] The above-mentioned paste material was uniformly rolled onto a carbon-coated aluminum foil current collector with a single-sided carbon layer thickness of 1 μm, and then dried by baking at 100°C for 2 minutes.

[0063] At a temperature of 60°C, the electrode sheet was rolled using a hot roller press with a roller diameter of 300 mm and a rolling pressure of 80 MPa. This sample is denoted as S1.

[0064] Example 2 This embodiment provides a positive electrode plate: The compacted density is approximately 2.45 g / cm³. 3 The thickness of the electrode sheet is 163 μm.

[0065] This embodiment also provides a quasi-dry preparation method for the above-mentioned positive electrode sheet. The difference from Example 1 is that the solvent is replaced with deionized water, and the amount is adjusted to 15% of the mass of the positive electrode active material. The binder solution is an aqueous solution of sodium carboxymethyl cellulose (CMC) (solid content 15%); that is, 2865g of lithium iron phosphate (LiFePO4) positive electrode active material, 75g of conductive carbon black (SP), and 400g of sodium carboxymethyl cellulose (CMC) with a solid content of 15%. After baking for 2 minutes, positive electrode sheet sample S2 is obtained.

[0066] Example 3 This embodiment provides a positive electrode plate: The compacted density is approximately 2.5 g / cm³. 3 The electrode sheet has a thickness of 300 μm.

[0067] This embodiment also provides a quasi-dry preparation method for the above-mentioned positive electrode sheet, using the same materials and proportions as in Example 1. The difference from Example 1 is that the target thickness of the dry-process positive electrode active material layer is designed to be 300 μm by adjusting the rolling thickness. After the same rolling process, it is dried for 2 minutes, and a crack-free, dense thick positive electrode sheet is successfully obtained, denoted as sample S3. The obtained positive electrode sheet is as follows: Figure 1 As shown.

[0068] Example 4 This embodiment provides a positive electrode plate: The compacted density is approximately 2.51 g / cm³. 3 The thickness of the electrode sheet is 163 μm.

[0069] This embodiment also provides a quasi-dry preparation method for the above-mentioned positive electrode sheet. The difference from Example 1 is that the current collector uses double-sided carbon-coated aluminum foil (carbon layer thickness of 2μm on one side) to obtain sample S4.

[0070] Example 5 This embodiment provides a positive electrode plate: The compacted density is approximately 2.52 g / cm³. 3 The thickness of the electrode sheet is 163 μm.

[0071] This embodiment also provides a quasi-dry preparation method for the above-mentioned positive electrode sheet. The difference from Example 1 is that the current collector is ordinary light aluminum foil (without carbon layer), and sample S5 is obtained.

[0072] Example 6 This embodiment provides a negative electrode plate: The compacted density is approximately 1.5 g / cm³. 3 The thickness of the electrode sheet is 121 μm.

[0073] This embodiment provides a quasi-dry preparation method for the above-mentioned negative electrode sheet, and the specific steps are as follows: 2865g of graphite anode active material, 60g of conductive carbon black (SP), and 400g of sodium carboxymethyl cellulose (PVDF) with a solid content of 15% were mixed. The amount of deionized water added was controlled to be 10% of the mass of the anode active material. The mixed material was a uniform paste with a solid content of approximately 88%.

[0074] The above-mentioned paste material was uniformly rolled onto a carbon-coated aluminum foil current collector with a single-sided carbon layer thickness of 1 μm, and then dried by baking at 100°C for 2 minutes.

[0075] At a temperature of 60°C, the electrode sheet was rolled using a hot roller press with a roller diameter of 300 mm and a rolling pressure of 80 MPa. This sample is designated as S6.

[0076] Comparative Example 1 This comparative example provides a traditional wet coating process for preparing positive electrode sheets, with the specific steps as follows: 2865g of lithium iron phosphate (LiFePO4), 75g of conductive carbon black (SP), and 400g of polyvinylidene fluoride (PVDF) solution with a solid content of 15% (the solid raw material ratio is the same as in Example 1) were dispersed in a large amount of NMP solvent to prepare a flowable slurry with a solid content of 55%. After coating onto ordinary aluminum foil, it was dried at 100°C for 10 minutes to remove the solvent, and then cold-pressed to obtain a positive electrode sheet with a compacted density of approximately 2.47 g / cm³, denoted as sample D1.

[0077] Comparative Example 2 This comparative example provides a traditional dry coating process for preparing positive electrode sheets, with the following specific steps: 2865g of lithium iron phosphate (LiFePO4), 75g of conductive carbon black (SP), and 60g of polytetrafluoroethylene (PTFE) binder were dry-mixed and fiberized, then directly hot-pressed into a film, and then thermally laminated with carbon-coated aluminum foil. No solvent was used in the entire process to obtain a positive electrode sheet, which was denoted as sample D2.

[0078] Comparative Example 3 This comparative example provides a positive electrode plate: The compacted density is approximately 2.44 g / cm³. 3 The thickness of the electrode sheet is approximately 163 μm.

[0079] This comparative example provides a quasi-dry preparation method for the above-mentioned positive electrode sheet, and the specific steps are as follows: Lithium iron phosphate (LiFePO4) cathode active material, conductive carbon black (SP), and a 15% solid content polyvinylidene fluoride (PVDF) / N-methylpyrrolidone (NMP) solution were mixed in the same proportions as in Example 1. The amount of NMP solvent added was controlled to be 30% of the mass of the cathode active material. The resulting mixture was a uniform paste.

[0080] The above-mentioned paste material was uniformly rolled onto a carbon-coated aluminum foil current collector with a single-sided carbon layer thickness of 1 μm, and then dried by baking at 100°C for 12 minutes.

[0081] At a temperature of 60°C, the electrode sheet was rolled using a hot roller press with a roller diameter of 300 mm and a rolling pressure of 80 MPa, denoted as sample D3.

[0082] Comparative Example 4 This comparative example provides a thick electrode sheet prepared using a traditional wet process: This comparative example uses the traditional wet process of Comparative Example 1 to prepare electrode sheets with the same areal density (corresponding to a dry film thickness of approximately 300 μm). After coating, severe cracking and curling occurred during the drying process, making it impossible to obtain a complete and usable thick electrode sheet. Figure 2 As shown.

[0083] The electrodes obtained in the examples and comparative examples were assembled into coin cell half-cells: In Examples 1-5 and Comparative Examples 1-3, the negative electrode was a lithium metal sheet (purchased from Shenzhen Kejing); the positive electrode in Example 6 was a lithium metal sheet (purchased from Shenzhen Kejing); the separator was a polypropylene microporous separator (purchased from Shenzhen Kangmo Technology Co., Ltd.); and the electrolyte was a 1 mol / L LiPF6 solution of ethylene carbonate / dimethyl carbonate (EC / DMC, volume ratio 1:1).

[0084] The battery electrodes prepared in the examples and comparative examples were subjected to comprehensive performance tests, and the test results are shown in Table 1: Table 1. Comprehensive performance test results of the electrode sheets prepared in the examples and comparative examples.

[0085] As can be seen from Table 1: Interfacial bonding and internal resistance performance: The peel strength of S1 and S2 is higher than that of D2 obtained by the pure dry method, proving that the introduction of a small amount of solvent / solution greatly improves the interfacial adhesion. At the same time, their electrode internal resistance is lower than that of D1 and D2, indicating that the present invention does not sacrifice the conductive network while enhancing the bonding force, but rather improves the conductivity due to the better interfacial contact.

[0086] Process and environmental advantages: S1 and S2 eliminate the high-energy-consuming and time-consuming drying steps of the traditional wet process (D1), and also avoid the strong dependence on specific fibrous binders (PTFE) and easy delamination problems of the pure dry process (D2). D3 demonstrates that when the solvent dosage exceeds the preferred range of this invention, the issues of drying energy consumption and electrode quality will reappear.

[0087] Thick electrode fabrication capability: S3 successfully fabricated a high-performance thick electrode (300 μm), while D4 failed to fabricate an electrode of the same thickness using a wet process. This highlights the unique advantage of the "quasi-dry" process of this invention in achieving the high-load electrodes required for high-energy-density batteries.

[0088] Electrochemical cycling performance: All embodiments of the present invention exhibited cycle capacity retention rates close to D1 (wet process) and significantly better than comparative example D2 (pure dry process), demonstrating that the technical solution of this application has no loss in terms of long-term battery stability.

[0089] Compacted density and process efficiency: Although the wet process (D1) can achieve a high compacted density (2.47 g / cm³) after coating, long drying time, and rolling, 3 However, the quasi-dry process of this application (S1, 2.52 g / cm³) 3 By omitting energy-intensive steps such as slurry dispersion, high-speed mixing, and prolonged drying, a compaction level comparable to or even slightly superior was achieved. This is attributed to the uniform mixing and initially dense structure of the quasi-dry process materials, making them more efficient in responding to subsequent rolling processes. D2 (pure dry method, 2.42 g / cm³) 3 The data from the present invention demonstrates, from the opposite perspective, that without solvent intervention, physical fiberization and hot pressing alone are insufficient to achieve the same level of electrode density. Therefore, this invention, while greatly simplifying the process and reducing energy consumption, ensures the density of the electrode structure, achieving a good balance between process efficiency and product performance.

[0090] In summary, through a systematic comparison of the examples and comparative examples, the quasi-dry cathode fabrication method described in this invention has been fully demonstrated. By introducing a small amount of solvent / solution, it successfully integrates the advantages of dry and wet processes. While ensuring the excellent mechanical and electrochemical properties of the electrode, it has outstanding advantages such as simplified process, energy saving and environmental protection, and suitability for thick electrode manufacturing, thus solving key problems in the prior art.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0092] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A quasi-dry electrode preparation method, characterized in that, include: The active material, conductive agent, solvent, and binder are mixed to obtain a composite material; The composite was placed on the current collector and then dried; After rolling, electrode sheets are obtained; The complex is a paste-like complex; the solid content of the complex is 76%-95%.

2. The method for preparing electrodes using the quasi-dry method according to claim 1, characterized in that, The composite material comprises, by weight (100%), 95% active material, 3% conductive agent, and 2% binder.

3. The method for preparing electrodes using the quasi-dry method according to claim 1, characterized in that, At least one of the following conditions must be met: A. The active material includes a positive electrode active material and a negative electrode active material; The positive electrode active material includes lithium iron phosphate; The negative electrode active material includes at least one of graphite, hard carbon, and silicon carbon; B. The conductive agent includes at least one of conductive carbon black, acetylene black, Ketjen black, carbon nanotubes, graphene, and carbon fiber; C. The solvent includes at least one of N-methylpyrrolidone, water, dimethyl sulfoxide, dimethylformamide, acetone, ethanol, and isopropanol; D. The adhesive comprises at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylonitrile, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide; E. The current collector includes a positive current collector and a negative current collector; The positive current collector includes one of the following: bright aluminum foil, etched aluminum foil, carbon-coated aluminum foil, and porous aluminum foil; The negative electrode current collector includes copper foil or carbon-coated copper foil.

4. The method for preparing electrode sheets using the quasi-dry method according to claim 3, characterized in that, The adhesive also includes copolymers or modifiers of at least one of polyvinylidene fluoride, polyacrylic acid, polyacrylonitrile, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyvinyl alcohol, and polyethylene oxide.

5. The method for preparing electrode sheets using the quasi-dry method according to claim 2, characterized in that, At least one of the following conditions must be met: F. The mass of the solvent is 0.5-20% of the mass of the positive electrode active material; G. The solid content of the adhesive is 1-20%.

6. The method for preparing electrodes using the quasi-dry method according to claim 1, characterized in that, The rolling temperature is 20-150℃, and the roller diameter is 100-600mm.

7. The method for preparing electrodes using the quasi-dry method according to any one of claims 1-6, characterized in that, The electrode includes a positive electrode and a negative electrode.

8. A battery electrode, characterized in that, The electrode was prepared using the quasi-dry method described in any one of claims 1-7.

9. The battery electrode according to claim 8, characterized in that, At least one of the following conditions must be met: a. The thickness of the battery electrode is 50-200 μm; b. The compaction density of the battery electrode is 2.45-2.54 g / cm³. 3 .

10. A lithium-ion battery, characterized in that, Includes the battery electrode as described in claim 8 or 9.

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