Preparation method for electrode sheet, electrode sheet preparation mold, and solid-state battery

Abstract

Provided are a preparation method for an electrode sheet, an electrode sheet preparation mold, and a solid-state battery. The preparation method comprises: acquiring a dried electrode sheet powder (10); acquiring a current collector powder (20); stacking the dried electrode sheet powder (10) and the current collector powder (20) to form a powder layer group (30); performing an overall pressure-maintaining treatment on the powder layer group (30) to obtain a composite pressed sheet (31), wherein the dried electrode sheet powder (10) is formed into an electrode sheet active layer (11) after the pressure-maintaining treatment, and the current collector powder (20) is formed into a current collector layer (21) after the pressure-maintaining treatment; and removing part of the electrode sheet active layer (11) of the composite pressed sheet to expose the current collector layer (21). The method has the advantage of achieving a relatively high density.

Description

Electrode preparation methods, electrode preparation molds, and solid-state batteries Related applications

[0001] This application incorporates Chinese Patent Application No. 2024118138096, filed on December 10, 2024, entitled “Method for preparing an electrode, an electrode preparation mold and a solid-state battery”, which is incorporated herein by reference in its entirety. Technical Field

[0002] This application relates to the field of battery technology, and in particular to a method for preparing an electrode, an electrode preparation mold, and a solid-state battery. Background Technology

[0003] Solid-state battery electrode preparation processes can be carried out using either dry or wet methods. Among them, the dry method is more promising than the wet method because it uses less solvent, does not require drying, has high efficiency, and low cost. Currently, the dry process mainly uses transfer printing to prepare electrodes, but this method has problems such as complicated process, high material consumption, and low compaction.

[0004] Traditional dry electrode manufacturing equipment is complex, mainly using rollers to repeatedly calender mixed materials to prepare films. This requires high processing pressure from the equipment, and the resulting electrode has low density, which cannot meet the requirements. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for preparing electrodes, an electrode preparation mold, and a solid-state battery to address the problem of low electrode density.

[0006] The first aspect of this application provides a method for preparing an electrode, comprising: obtaining electrode dry powder; obtaining current collector powder; stacking the electrode dry powder and the current collector powder to form a powder layer assembly; subjecting the powder layer assembly to overall pressure holding treatment to obtain a composite tablet; wherein, the electrode dry powder forms an electrode active layer after pressure holding treatment, and the current collector powder forms a current collector layer after pressure holding treatment; and removing a portion of the electrode active layer of the composite tablet to expose the current collector layer.

[0007] In one embodiment, the preparation method is used to prepare a positive electrode sheet; the step of obtaining the electrode sheet dry powder specifically includes: uniformly mixing the positive electrode active material, the positive electrode electrolyte, the positive electrode conductive agent and the positive electrode binder; the mass ratio of the positive electrode active material, the positive electrode electrolyte, the positive electrode conductive agent and the positive electrode binder is (90~97):(1~3):(0.5~4.5):(0.5~4.5).

[0008] In one embodiment, the positive electrode active material includes at least one of lithium iron phosphate and ternary lithium; the positive electrode electrolyte includes at least one of sulfide solid electrolyte, oxide solid electrolyte and halide electrolyte; the positive electrode conductive agent includes at least one of conductive carbon black, carbon nanotubes, graphene and carbon fiber; and the positive electrode binder includes at least one of polytetrafluoroethylene and modified polytetrafluoroethylene.

[0009] In one embodiment, the preparation method is used to prepare a negative electrode sheet; the step of obtaining the electrode sheet dry powder specifically includes: uniformly mixing the negative electrode active material, the negative electrode conductive agent and the negative electrode binder; the mass ratio of the negative electrode material, the negative electrode conductive agent and the negative electrode binder is (90-95):(2-8):(2-8).

[0010] In one embodiment, the negative electrode active material includes at least one of silver-carbon and silicon-carbon; the conductive agent includes at least one of conductive carbon black, carbon nanotubes, graphene and carbon fiber; and the binder includes at least one of polytetrafluoroethylene and modified polytetrafluoroethylene.

[0011] In one embodiment, the current collector powder includes at least one of aluminum powder, copper powder, nickel powder, aluminum alloy powder, copper alloy powder, and stainless steel powder.

[0012] In one embodiment, the step of stacking electrode powder and current collector powder to form a powder layer assembly specifically includes:

[0013] The first layer of electrode powder, the current collector powder, and the second layer of electrode powder are stacked in sequence to form a powder layer group.

[0014] In one embodiment, the thickness of the electrode active layer is 50-300 μm; the thickness of the current collector layer is 5 μm-15 μm.

[0015] In one embodiment, the electrode powder is applied by electrostatic spraying, extrusion coating, or dry powder spraying; the current collector powder is applied by electrostatic spraying, extrusion coating, or dry powder spraying.

[0016] In one embodiment, the step of stacking electrode dry powder and current collector powder to form a powder layer assembly includes: accommodating the electrode dry powder and current collector powder stacked in an electrode preparation mold to form a powder layer assembly; the overall shrinkage rate of the material of the electrode preparation mold is 3% to 80%.

[0017] In one embodiment, the step of performing overall pressure holding treatment on the powder layer group to obtain a composite tablet specifically includes: uniformly extruding the electrode preparation mold from all sides using a working medium at a preset pressure and a preset temperature for a preset time; and removing the composite tablet from the electrode preparation mold.

[0018] In one embodiment, the preset pressure is 2MPa to 3500MPa; the preset temperature is 15℃ to 1200℃; the preset time is 2min to 40min; and the working medium is ester, water, or inert gas.

[0019] In one embodiment, the step of removing a portion of the active electrode layer of the composite tablet to expose the current collector layer specifically includes: removing a portion of the active electrode layer to expose the current collector layer by means of solvent wiping, laser cleaning, or mechanical polishing.

[0020] A second aspect of this application provides an electrode preparation mold for use in the above-described preparation method. The electrode preparation mold includes a mold cover and a mold body that overlap each other, and the mold cover and the mold body together define a mold cavity for accommodating a powder layer assembly.

[0021] In one embodiment, the material of the electrode preparation mold includes at least one of polyimide, polyetheretherketone, polytetrafluoroethylene, polypropylene, polyethylene, and polyvinyl chloride.

[0022] In one embodiment, the airtightness of the electrode preparation mold is 1E-09Pa m3 / s to 1E-06Pa m3 / s.

[0023] A third aspect of this application provides a solid-state battery, including an electrode prepared by the above-described preparation method.

[0024] The beneficial effects are as follows: The battery electrode preparation method of this application obtains electrode dry powder and current collector powder, stacks them in a preset manner to form a powder layer group, and performs overall pressure holding treatment using isostatic pressing, so that the electrode dry powder forms the electrode active layer and the current collector powder forms the current collector layer; this allows the battery electrode to be formed in one step, avoiding the multiple rolling and pressing processes in the traditional dry process, eliminating the need for multiple transfer processes in the traditional dry process, thereby reducing the consumption of transfer consumables; thus, it simplifies the preparation process, improves production efficiency, and reduces production costs; in addition, since the powder layer group is subjected to overall pressure holding, the pressure in all directions is the same, so a larger holding pressure can be set as needed, and the electrode active layer and current collector layer have high strength and good adhesion, which on the one hand greatly improves the density and uniformity of the electrode, reduces the generation of defects, and on the other hand, the increased strength can be used to prepare electrode sheets with larger thicknesses, providing more possibilities for the design of solid-state batteries; by removing part of the active layer of the electrode in the composite pressing, the current collector layer is exposed, which facilitates subsequent battery assembly and ultimately improves the overall performance of the battery.

[0025] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort. In the drawings:

[0027] Figure 1 is a flowchart of a method for preparing an electrode according to some embodiments of this application.

[0028] Figure 2 is a flowchart of a method for preparing an electrode according to other embodiments of this application.

[0029] Figure 3 is a cross-sectional schematic diagram of the powder layer assembly and electrode preparation mold provided in some embodiments of this application.

[0030] Figure 4 is a cross-sectional schematic diagram of the composite tablet and electrode preparation mold provided in some embodiments of this application in the working medium; wherein, the arrow represents the pressure applied by the working medium.

[0031] Figure 5 is a schematic diagram of the change of composite compression to electrode provided in some embodiments of this application, wherein the arrows represent the trend of change.

[0032] Explanation of reference numerals in the attached figures:

[0033] Electrode dry powder-10, electrode active layer-11, current collector powder-20, current collector layer-21, powder layer group-30, composite tablet-31, electrode preparation mold-40, mold cover-41, mold body-42, mold cavity-43, working medium-50. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0036] In the description of the embodiments of this application, if the technical terms such as "first" and "second" appear, these terms are used only for descriptive purposes to distinguish different objects, and should not be construed as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0037] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0038] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0039] In the description of the embodiments of this application, if the term "multiple" appears, "multiple" means at least two (including two), such as two, three, etc., unless otherwise explicitly specified. Similarly, if the term "multiple sets" appears, "multiple sets" refers to two or more sets (including two sets), and if the term "multiple pieces" appears, "multiple pieces" refers to two or more pieces (including two pieces).

[0040] In the description of the embodiments of this application, if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0041] In the description of the embodiments of this application, unless otherwise explicitly specified and limited, the technical terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0044] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0045] Solid-state batteries, as one of the future development trends in batteries, have advantages such as high density, high energy density, and good safety. With the technological advancement of solid-state batteries, higher requirements are being placed on their density. In related technologies, the electrode fabrication process for solid-state batteries typically includes wet and dry processes. The wet process involves mixing binders and active electrode components with a solvent to prepare a slurry, then coating the slurry onto a current collector, and finally drying to remove the solvent to form a film on the current collector. The dry process, on the other hand, involves directly dry-mixing binders, active electrode components, and a conductive agent, then calendering the mixture to form a film layer, which is then composited with the current collector. Compared with wet processes, dry processes have significant advantages: they can produce both thin and thick films; the electrode strength is high; the adhesion to the current collector is strong; and there are fewer defects (such as holes, cracks, surface protrusions or depressions on the electrode). However, the manufacturing equipment for traditional dry electrode sheets is complex. In the process of calendering dry mixtures to prepare electrode sheets, after calendering by a pair of rollers, the mixture is then conveyed to a second pair of rollers through guide rollers and tension regulating rollers. Only after multiple calendering processes can the electrode sheet be obtained. This not only limits the thickness of the electrode sheet and the production efficiency, but also the pressure of the dry mixture passing through the rollers each time cannot be too high, which greatly limits the density of the electrode sheet formed after rolling.

[0046] To alleviate the problem of low density, the multiple rolling processes in the original dry process can be eliminated. Instead, the electrode powder can be placed uniformly in a mold and subjected to overall isostatic pressing. Isostatic pressing allows for setting a higher holding pressure, resulting in high strength and good adhesion of the electrode, which greatly improves the density and uniformity of the electrode and reduces the occurrence of defects.

[0047] This application provides a preparation method for preparing electrode sheets for batteries, which can provide electrical energy to or store electrical energy in electrical devices. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0048] It should be understood that the batteries described in the embodiments of this application can be solid-state batteries using solid materials as electrolytes or liquid-state batteries using liquid materials as electrolytes; however, for the sake of brevity, unless otherwise specified, the batteries mentioned in the following embodiments are all solid-state batteries.

[0049] Solid-state batteries, as one of the future development trends in batteries, have advantages such as high density, high energy density, and good safety. With the technological advancement of solid-state batteries, higher requirements are being placed on their density. In related technologies, the electrode fabrication process for solid-state batteries typically includes wet and dry processes. The wet process involves mixing binders and active electrode components with a solvent to prepare a slurry, then coating the slurry onto a current collector, and finally drying to remove the solvent to form a film on the current collector. The dry process, on the other hand, involves directly dry-mixing binders, active electrode components, and a conductive agent, then calendering the mixture to form a film layer, which is then composited with the current collector. Compared with wet processes, dry processes have significant advantages: they can produce both thin and thick films; the electrode strength is high; the adhesion to the current collector is strong; and there are fewer defects (such as holes, cracks, surface protrusions or depressions on the electrode). However, the manufacturing equipment for traditional dry electrode sheets is complex. In the process of calendering dry mixtures to prepare electrode sheets, after calendering by a pair of rollers, the mixture is then conveyed to a second pair of rollers through guide rollers and tension regulating rollers. Only after multiple calendering processes can the electrode sheet be obtained. This not only limits the thickness of the electrode sheet and the production efficiency, but also the pressure of the dry mixture passing through the rollers each time cannot be too high, which greatly limits the density of the electrode sheet formed after rolling.

[0050] Referring to Figures 1 to 5, the first aspect of this application provides a preparation method that can be used to prepare electrode sheets for batteries.

[0051] Preparation methods include:

[0052] S10. Obtain 10g of electrode dry powder.

[0053] S20, Obtain current collector powder 20.

[0054] S30, The electrode dry powder 10 and the current collector powder 20 are stacked to form a powder layer group 30.

[0055] S40. The powder layer group 30 is subjected to overall pressure holding treatment to obtain composite tablet 31; wherein, the electrode dry powder 10 is formed into electrode active layer 11 after pressure holding treatment, and the current collector powder 20 is formed into current collector layer 21 after pressure holding treatment.

[0056] S50. Remove a portion of the electrode active layer 11 of the composite tablet 31 to expose the current collector layer 21.

[0057] The battery electrode preparation method of this application involves obtaining electrode dry powder 10 and current collector powder 20, stacking them in a preset manner to form a powder layer group 30, and performing an overall pressure holding treatment by isostatic pressing, so that the electrode dry powder 10 forms an electrode active layer 11 with a thickness of 50-300um; and the current collector powder 20 forms a current collector layer 21 with a thickness of 5um-15um.

[0058] Thus, the preparation method of this application allows the battery electrode to be formed in one step, avoiding the multiple rolling and pressing processes in the traditional dry process, and eliminating the need for multiple transfer processes in the traditional dry process, thereby reducing the consumption of transfer consumables (polytetrafluoroethylene); it also simplifies the preparation process, improves production efficiency, and reduces production costs; in addition, since the powder layer group 30 adopts overall pressure holding, the pressure in all directions is the same, so a larger holding pressure can be set as needed. The electrode active layer 11 and the current collector layer 11 have high strength and good adhesion, which greatly improves the density and uniformity of the electrode and reduces the generation of defects. On the other hand, the increased strength can be used to prepare electrodes with greater thickness, providing more possibilities for the design of solid-state batteries; by removing part of the active layer of the electrode in the composite pressing, the current collector layer is exposed, which facilitates the subsequent battery assembly and ultimately improves the overall performance of the battery.

[0059] In some possible embodiments, referring to Figures 1 to 5, the preparation method can be used to prepare the positive electrode sheet.

[0060] Specifically, step S10, obtaining electrode dry powder 10, includes:

[0061] The positive electrode active material, positive electrode electrolyte, positive electrode conductive agent, and positive electrode binder are uniformly mixed. The mass ratio of the positive electrode active material, positive electrode electrolyte, positive electrode conductive agent, and positive electrode binder is (90-97):(1-3):(0.5-4.5):(0.5-4.5).

[0062] In the composition, the positive electrode active material, positive electrode electrolyte, positive electrode conductive agent and positive electrode binder are prepared in a mass ratio of (90-97):(1-3):(0.5-4.5):(0.5-4.5), and after being ball-milled and stirred at high speed, electrode powder 10 is obtained; thus, the subsequent preparation of the electrode is carried out.

[0063] In some possible embodiments, as shown in Figures 1 to 5, the positive electrode active material includes at least one of lithium iron phosphate and ternary lithium.

[0064] Specifically, the positive electrode active material can be a core-shell structure, and the positive electrode active material includes a positive electrode active substrate and a coating layer on the surface of the positive electrode active substrate, the coating layer including an ion conductor material.

[0065] The general chemical formula of the positive electrode active substrate includes LiNixCoyMzO2, where x≥0, y≥0, z≥0, and x+y+z=1, and M can represent at least one of manganese (Mn), aluminum (Al), zirconium (Zr), titanium (Ti), vanadium (V), magnesium (Mg), iron (Fe), and molybdenum (Mo). Exemplarily, the positive electrode active substrate includes at least one of LiNi0.8Co0.1M0.1O2, LiNi0.83Co0.11M0.06O2, LiNi0.85Co0.09M0.06O2, or LiNi0.88Co0.09M0.03O2.

[0066] Ion conductor materials include at least one of Li₂TiO₃ (lithium titanate), LiNbO₃ (lithium niobate), Li₃BO₃ (lithium borate), Li₂ZrO₃ (lithium zirconate), LiCoO₃ (lithium cobalt oxide), LiPO₃ (lithium phosphate), Li₂MnO₄ (lithium manganese oxide), Al(PO₃)₃ (aluminum metaphosphate), La(PO₃)₃ (lanthanum metaphosphate), and NaPO₃ (sodium metaphosphate). They can be any one of these materials, or a combination of two or more, such as a combination of Li₂TiO₃, LiNbO₃, and Li₃BO₃, or a combination of LiCoO₃ and LiPO₃.

[0067] The coating thickness is 1–10 nm. In one embodiment, the coating thickness includes, but is not limited to, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, and 10 nm. The aforementioned suitable coating thickness enables the positive electrode active material to possess excellent electrochemical performance.

[0068] In some possible embodiments, as shown in Figures 1 to 5, the positive electrode electrolyte includes at least one of a sulfide solid electrolyte, an oxide solid electrolyte, and a halide electrolyte.

[0069] Among them, sulfide solid electrolytes have high lithium-ion conductivity of 10⁻² S / cm to 10⁻³ S / cm, which can easily form a contact interface between the electrode and the electrolyte, and also have high mechanical strength and flexibility. In the embodiments of this application, there are no particular limitations on the type of sulfide solid electrolyte, and all known sulfide materials used in the battery field are acceptable. In the embodiments of this application, the sulfide solid electrolytes include Li6PS5Cl (LPSCl), Thio-LISICON (Li3.25Ge0.25P0.75S4), Li2S-P2S5-LiCl, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5, Li3PS4, Li7P3S11, LiI-Li2S-B2S3, Li3PO4-Li2S-Si2S, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, Li10GeP2S12, Li9.54Si1.74P1.44S11.7Cl0.3, and Li7P3S11.

[0070] Oxide-based solid-state electrolytes exhibit high safety in air and possess lithium-ion conductivity ranging from 10⁻³ S / cm to 10⁻⁴ S / cm, which is lower than, but relatively higher than, that of sulfide-based solid-state electrolytes. Furthermore, oxide-based solid-state electrolytes exhibit high electrochemical safety and mechanical strength. In the embodiments of this application, the oxide-based solid-state electrolyte can be any known oxide material used in the field of lithium batteries. In the embodiments of this application, the oxide-based solid-state electrolyte includes perovskite solid-state electrolyte, sodium superionic conductor solid-state electrolyte (NASICON), lithium superionic conductor solid-state electrolyte (LISICON), and lithium lanthanum zirconium oxide solid-state electrolyte (LLZO).

[0071] Halogen electrolytes are special ionic conductors with the general chemical formula LiaMXb, where M represents a metallic element (such as yttrium (Y), erbium (Er), ytterbium (Yb), indium (In), and zirconium (Zr), X represents a halogen element (such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), etc.), and Li mainly comes from lithium salts, such as Li oxides, carbonates, chlorides, and hydroxides. Halogen electrolytes possess ion conductivity in the solid state and are key materials for achieving rapid lithium-ion transport. Halogen electrolytes can be any known halide material used in the field of lithium batteries. In the embodiments of this application, the halide electrolytes include Li3YCl6, Li3BrY6, Li3ErCl6, Li3YbCl6, LiInxSc0.66-xCl4, Li2.5Y0.5Zr0.5Cl6, and Li3ErI6.

[0072] In some possible embodiments, as shown in Figures 1 to 5, the positive electrode conductive agent includes at least one of conductive carbon black, carbon nanotubes, graphene, and carbon fiber.

[0073] Specifically, the positive electrode conductive agent may include zero-dimensional conductive agents, one-dimensional conductive agents, and two-dimensional conductive agents. Zero-dimensional conductive agents may include dot-shaped conductive agents; zero-dimensional conductive agents may include conductive carbon black and / or AB; one-dimensional conductive agents are linear conductive agents and / or tubular conductive agents. One-dimensional conductive agents include carbon nanotubes and / or carbon fibers. Two-dimensional conductive agents include graphene. The positive electrode conductive agents in the embodiments of this application may generally include graphite (e.g., natural graphite or artificial graphite), carbon black (e.g., acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black), conductive fibers (e.g., carbon fibers or metal fibers), metal powders (e.g., fluorinated carbon powder, aluminum powder, or nickel powder), conductive whiskers (e.g., zinc oxide or potassium titanate), conductive metal oxides (e.g., titanium oxide), or conductive materials (e.g., polyphenylene derivatives) as positive electrode conductive agents.

[0074] In some possible embodiments, as shown in Figures 1 to 5, the positive electrode binder includes at least one of polytetrafluoroethylene and modified polytetrafluoroethylene.

[0075] A positive electrode binder is a component that facilitates the bonding between the positive electrode active material and the positive electrode conductive agent. Based on the total weight of the composite including the positive electrode active material, the binder is typically added in an amount of 0.1 to 30% by weight. In the embodiments of this application, there are no particular limitations on the binder, and any known binder can be used. Specifically, the positive electrode binder may include at least one of polytetrafluoroethylene and modified polytetrafluoroethylene. In addition, in the embodiments of this application, the positive electrode binder may also be any one or a mixture of two or more of the following: polyamide-imide (PAI), polyimide (PI), polyamide (PA), polyamic acid, polyethylene oxide (PEO), polystyrene (PS), poly(ethylene-co-propylene-co-5-methylene-2-norbornene) (PEP-MNB), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polystyrene-acrylonitrile-butadiene rubber (PS-NBR), poly(methacrylate)-acrylonitrile-butadiene rubber (PMMA-NBR), and mixtures thereof; the specific design shall prevail, and this application does not impose any limitations on this.

[0076] In some possible embodiments, referring to Figures 1 to 5, the preparation method is used to prepare the negative electrode sheet.

[0077] Specifically, step S10, obtaining electrode dry powder 10, includes:

[0078] The negative electrode active material, the negative electrode conductive agent, and the negative electrode binder are uniformly mixed; the mass ratio of the negative electrode material, the negative electrode conductive agent, and the negative electrode binder is (90 - 95):(2 - 8):(2 - 8).

[0079] In the components, the negative electrode active material, the negative electrode conductive agent, and the negative electrode binder are configured according to the mass ratio of (90 - 95):(2 - 8):(2 - 8), and after ball milling and high-speed stirring in sequence, the electrode sheet dry powder 10 is obtained; thus, the subsequent preparation of the electrode sheet is carried out.

[0080] In some possible embodiments, as shown in FIGS. 1 to 5, the negative electrode active material includes at least one of silver carbon and silicon carbon.

[0081] Specifically, in addition to silver carbon and silicon carbon, other carbon materials (for example, one or more of non-graphitized carbon or graphite-like carbon, artificial graphite, natural graphite, graphitized mesophase carbon microspheres, hard carbon, soft carbon, activated carbon) can be used as the negative electrode active material; the negative electrode active material can also use lithium metal, lithium alloy, silicon-based alloy, tin-based alloy, conductive polymer (such as polyacetylene), metal oxide (such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 or Bi2O5) materials, metal composite oxides (such as LixFe2O3 (0 ≤ x ≤ 1), LixWO2 (0 ≤ x ≤ 1), SnxMe1-xMe'yOz; where 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8; Me can represent manganese (Mn), iron (Fe), lead (Pb) or germanium (Ge); Me’ can represent aluminum (Al), boron (B), phosphorus (P), silicon (Si), elements of Groups 1, 2 and 3 of the periodic table, halogen; the embodiments of the present application are not limited thereto).

[0082] In some possible embodiments, as shown in FIGS. 1 to 5, the negative electrode conductive agent includes at least one of conductive carbon black, carbon nanotubes, graphene, and carbon fibers.

[0083] Specifically, the negative electrode conductive agent may include zero-dimensional conductive agents, one-dimensional conductive agents, and two-dimensional conductive agents. Zero-dimensional conductive agents may include dot-shaped conductive agents; zero-dimensional conductive agents may include conductive carbon black and / or AB; one-dimensional conductive agents are linear conductive agents and / or tubular conductive agents. One-dimensional conductive agents include carbon nanotubes and / or carbon fibers. Two-dimensional conductive agents include graphene. The negative electrode conductive agents in the embodiments of this application may generally include graphite (e.g., natural graphite or artificial graphite), carbon black (e.g., acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black), conductive fibers (e.g., carbon fibers or metal fibers), metal powders (e.g., fluorinated carbon powder, aluminum powder, or nickel powder), conductive whiskers (e.g., zinc oxide or potassium titanate), conductive metal oxides (e.g., titanium oxide), or conductive materials (e.g., polyphenylene derivatives) as negative electrode conductive agents.

[0084] In some possible embodiments, as shown in Figures 1 to 5, the negative electrode binder includes at least one of polytetrafluoroethylene and modified polytetrafluoroethylene.

[0085] A negative electrode binder is a component that facilitates the bonding between the negative electrode active material and the negative electrode conductive agent. Based on the total weight of the composite including the negative electrode active material, the binder is typically added in an amount of 0.1 to 30% by weight. In the embodiments of this application, there are no particular limitations on the binder, and any known binder can be used. Specifically, the negative electrode binder may include at least one of polytetrafluoroethylene and modified polytetrafluoroethylene. In addition, in the embodiments of this application, the negative electrode binder may also be any one or a mixture of two or more of the following: polyamide-imide (PAI), polyimide (PI), polyamide (PA), polyamic acid, polyethylene oxide (PEO), polystyrene (PS), poly(ethylene-co-propylene-co-5-methylene-2-norbornene) (PEP-MNB), polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polystyrene-acrylonitrile-butadiene rubber (PS-NBR), poly(methacrylate)-acrylonitrile-butadiene rubber (PMMA-NBR), and mixtures thereof; the specific design shall prevail, and this application does not impose any limitations on this.

[0086] In some possible embodiments, as shown in Figures 1 to 5, the current collector powder 20 includes at least one of aluminum powder, copper powder, nickel powder, aluminum alloy powder, copper alloy powder, and stainless steel powder.

[0087] In some possible embodiments, referring to Figures 1 to 5, the electrode powder 10 is coated by electrostatic spraying, extrusion coating, or dry powder spraying; the current collector powder 20 is coated by electrostatic spraying, extrusion coating, or dry powder spraying. This ensures that the electrode powder 10 and the current collector powder 20 are uniformly layered, thereby ensuring that the thickness of each layer of the composite sheet 31 after pressure holding meets the expected design, greatly improving the density and uniformity of the electrode, reducing defects, and ultimately improving the overall performance of the battery.

[0088] In some possible embodiments, referring to Figures 1 to 5, step S30, stacking the electrode dry powder 10 and the current collector powder 20 to form a powder layer assembly 30, includes:

[0089] S31. The electrode dry powder 10 and the current collector powder 20 are stacked and contained in the electrode preparation mold 40 to form a powder layer group 30; the overall shrinkage rate of the material of the electrode preparation mold 40 is 3% to 80%.

[0090] Thus, the electrode preparation mold 40 is used as a container to hold the powder layer group 30. The electrode preparation mold 40 adopts overall pressure holding. The working medium 50 (mentioned below) can apply pressure to the electrode preparation mold 40 in all directions. The electrode preparation mold 40 uniformly transmits the isostatic pressure and temperature to the powder layer group 30, so that the powder layer group 30 is subjected to the same pressure in all directions. Therefore, the external pressure holding equipment can be set to a larger pressure holding as needed, thereby ensuring that the electrode active layer 11 and the current collector layer 11 have high strength and good adhesion, greatly improving the density and uniformity of the electrode, reducing the generation of defects, and allowing for the selection of ultra-thick electrode preparation as needed.

[0091] In some possible embodiments, step S30, which involves stacking the electrode powder 10 and the current collector powder 20 to form a powder layer assembly 30, specifically includes:

[0092] S32. The first layer of electrode dry powder 10, the current collector powder 20 and the second layer of electrode dry powder 10 are stacked in sequence to form a powder layer group 30.

[0093] The powder layer 30 can be accommodated in the electrode preparation mold 40.

[0094] That is, firstly, the first layer of electrode dry powder 10 is evenly distributed into the mold cavity 43 (mentioned below) of the electrode preparation mold 40; then, current collector powder 20, which can be aluminum powder, is evenly distributed on the upper surface of the first layer of electrode dry powder 10; then, the second layer of electrode dry powder 10 is evenly distributed onto the surface of the current collector powder 20. The distribution method can be dry powder spraying to ensure uniform thickness. This ensures that after isostatic pressing, an electrode active layer 11 can be formed on each side of the current collector layer 21, which facilitates the stacking of multiple electrodes and thus meets the needs of battery use.

[0095] In some possible embodiments, referring to Figures 1 to 5, the electrode active layer 11 formed by the first layer of electrode dry powder 10 has a thickness of 100um-200um; the current collector layer 21 formed by the current collector powder 20 has a thickness of 8um-13um; and the electrode active layer 11 formed by the second layer of electrode dry powder 10 has a thickness of 100um-200um.

[0096] In some possible embodiments, referring to Figures 1 to 5, step S40, performing overall pressure holding treatment on the powder layer group 30 to obtain the composite tablet 31, specifically includes:

[0097] S41. Under preset pressure and preset temperature, the working medium 50 is used to uniformly extrude the electrode sheet from all sides to prepare the mold 40, and this process is continued for a preset time.

[0098] S42. Take out the composite tablet 31 from the electrode preparation mold 40.

[0099] Among them, S41 can be pressed using a warm isostatic pressing process.

[0100] The isostatic pressing process utilizes Pascal's principle. The electrode preparation mold 40 is placed in a pressure vessel filled with working medium 50. The pressure vessel applies a certain pressure to the working medium 50, and the pressure is transmitted evenly to the electrode preparation mold 40 in all directions through the working medium. Under the action of isostatic pressure, the electrode preparation mold 40 undergoes a certain volume deformation, thereby achieving isostatic pressing. In some embodiments, the composite sheet 31 inside the electrode preparation mold 40 can be compressed in volume and its density can be increased, thereby providing higher energy density and meeting the battery usage requirements.

[0101] In this embodiment, the preset pressure can be 2MPa to 3500MPa; the preset temperature can be 15℃ to 1200℃; the preset time can be 2min to 40min; and the working medium is ester, water, or inert gas.

[0102] Specifically, the preset pressure is 2MPa to 3000MPa, the preset temperature is 25℃ to 1000℃, and the preset time is 5 to 30 minutes. The powder layer assembly 30 is placed inside a sealed electrode preparation mold 40. The working medium is heat-conducting oil. Under preset pressure conditions of 50MPa to 600MPa and preset temperature conditions of 25℃ to 150℃, the electrode preparation mold 40 is uniformly extruded from all sides using the working medium 50 for 5 to 30 minutes. This allows the composite pressed sheet 31 to achieve increased density in some embodiments after pressure holding, thereby providing higher energy density to meet the battery's usage requirements. Specific parameters can be adjusted according to actual conditions, and this application does not limit this.

[0103] In some possible embodiments, referring to Figures 1 to 5, step S50, removing a portion of the electrode active layer 11 on the composite tablet 31 to expose the current collector layer 21, specifically includes:

[0104] S51. Use solvent wiping, laser cleaning or mechanical polishing to remove part of the active layer 11 of the electrode to expose the current collector layer 21.

[0105] In this way, by wiping with solvents, cleaning with lasers, or polishing with mechanical polishing, some areas of the active layer of the electrode in the composite tablet are removed, exposing the current collector layer, which facilitates subsequent battery assembly and ultimately improves the overall performance of the battery.

[0106] In some embodiments, the solvent is alcohol.

[0107] Example 1

[0108] This embodiment provides a method for preparing an electrode sheet, as shown in Figures 1 to 5. The preparation method includes:

[0109] Obtain electrode dry powder 10. The dry powder is composed of 811NCM (ternary lithium material), sulfide electrolyte, polytetrafluoroethylene (PTFE) and conductive carbon black. 95% 811NCM, 2.5% sulfide electrolyte and 0.5% conductive carbon black are mixed, and then 2% PTFE is added. The mixture is then ball-milled and stirred at high speed to obtain electrode dry powder 10.

[0110] Aluminum powder is ball-milled and stirred at high speed to obtain current collector powder 20.

[0111] The electrode dry powder 10 and the current collector powder 20 are stacked and contained in the electrode preparation mold 40 to form a powder layer group 30. Specifically, the first layer of electrode dry powder 10, the current collector powder 20 and the second layer of electrode dry powder 10 are stacked and contained in the electrode preparation mold 40 in sequence to form a powder layer group 30.

[0112] Under preset pressure and temperature, the electrode sheet is uniformly extruded from all sides using working medium 50 to prepare mold 40 for a preset time. The preset pressure is 100 MPa, the preset temperature is 90℃, and the preset time is 10 min.

[0113] Take out the composite tablet 31 from the electrode preparation mold 40.

[0114] Laser cleaning is used to remove a portion of the active layer 11 of the electrode to expose the current collector layer 21.

[0115] Experimental electrode I was finally obtained. The measured density of experimental electrode I was 2.813 g / ml, and based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, resulting in a density of 97%. The theoretical density was calculated from the theoretical density of different components and their mass percentages.

[0116] Comparative Example 1

[0117] This comparative example provides a method for preparing an electrode sheet. The difference between this method and Example 1 is that, under the same conditions, the powder layer 30 is pressed using a roller pressing method. Comparative electrode sheet I is obtained.

[0118] The measured density of control electrode I was 2.03 g / ml. Based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, and the density of control electrode I was 70%.

[0119] Example 2

[0120] This embodiment provides a method for preparing an electrode sheet, as shown in Figures 1 to 5. The preparation method includes:

[0121] Obtain electrode dry powder 10. Mix the dry powder, which is lithium iron phosphate, sulfide electrolyte, polytetrafluoroethylene (PTFE) and conductive carbon black. Mix 97% lithium iron phosphate, 1% sulfide electrolyte and 1% conductive carbon black, and then add 1% PTFE. After ball milling and high-speed stirring, electrode dry powder 10 is obtained.

[0122] Aluminum powder is ball-milled and stirred at high speed to obtain current collector powder 20.

[0123] Electrode powder 10 and current collector powder 20 are stacked and contained in electrode preparation mold 40 to form powder layer assembly 30. Specifically, a first layer of electrode powder 10, a current collector powder 20, and a second layer of electrode powder 10 are sequentially stacked and contained in electrode preparation mold 40 to form powder layer assembly 30.

[0124] Under preset pressure and temperature, the electrode sheet is uniformly extruded from all sides using working medium 50 to prepare mold 40 for a preset time. The preset pressure is 150 MPa, the preset temperature is 90℃, and the preset time is 15 min.

[0125] Take out the composite tablet 31 from the electrode preparation mold 40.

[0126] Laser cleaning is used to remove a portion of the active layer 11 of the electrode to expose the current collector layer 21.

[0127] Experimental electrode II was finally obtained. The measured density of experimental electrode II was 2.813 g / ml, and based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, resulting in a density of 97%. The theoretical density was calculated from the theoretical density of different components and their mass percentages.

[0128] Comparative Example 2

[0129] This comparative example provides a method for preparing an electrode sheet. The difference between this method and Example 2 is that, under the same conditions, the powder layer 30 is pressed using a roller pressing method. Comparative electrode sheet II is obtained.

[0130] The measured density of the control electrode II was 2.03 g / ml. Based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, and the density of the control electrode II was 70%.

[0131] Example 3

[0132] This embodiment provides a method for preparing an electrode sheet, as shown in Figures 1 to 5. The preparation method includes:

[0133] Obtain electrode dry powder 10. The dry powder is composed of lithium iron phosphate, halide electrolyte, polytetrafluoroethylene (PTFE) and conductive carbon black. 92% lithium iron phosphate, 3% halide electrolyte and 2% conductive carbon black are mixed, and then 3% PTFE is added. After ball milling and high-speed stirring, electrode dry powder 10 is obtained.

[0134] Aluminum powder is ball-milled and stirred at high speed to obtain current collector powder 20.

[0135] The electrode dry powder 10 and the current collector powder 20 are stacked and contained in the electrode preparation mold 40 to form a powder layer group 30. Specifically, the first layer of electrode dry powder 10, the current collector powder 20 and the second layer of electrode dry powder 10 are stacked and contained in the electrode preparation mold 40 in sequence to form a powder layer group 30.

[0136] Under preset pressure and temperature, the electrode sheet is uniformly extruded from all sides using working medium 50 to prepare mold 40 for a preset time. The preset pressure is 200 MPa, the preset temperature is 120°C, and the preset time is 15 min.

[0137] Take out the composite tablet 31 from the electrode preparation mold 40.

[0138] Laser cleaning is used to remove a portion of the active layer 11 of the electrode to expose the current collector layer 21.

[0139] Experimental electrode III was finally obtained. The measured density of experimental electrode III was 2.755 g / ml, and based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, resulting in a density of 95% for experimental electrode III. The theoretical density was calculated from the theoretical density of different components and their mass percentages.

[0140] Comparative Example 3

[0141] This comparative example provides a method for preparing an electrode, which differs from Example 3 in that, under the same conditions, the powder layer 30 is pressed using a roller pressing method. Comparative electrode III is obtained.

[0142] The measured density of the control electrode III was 2.03 g / ml. Based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, and the density of the control electrode III was 70%.

[0143] Example 4

[0144] This embodiment provides a method for preparing an electrode sheet, as shown in Figures 1 to 5. The preparation method includes:

[0145] Obtain electrode dry powder 10. The dry powder is composed of 811NCM, oxide electrolyte, polytetrafluoroethylene (PTFE) and conductive carbon black. 95% of 811NCM, 2.5% of oxide electrolyte and 0.5% of conductive carbon black are mixed, and then 2% of PTFE is added. After ball milling and high-speed stirring, electrode dry powder 10 is obtained.

[0146] Aluminum powder is ball-milled and stirred at high speed to obtain current collector powder 20.

[0147] The electrode dry powder 10 and the current collector powder 20 are stacked and contained in the electrode preparation mold 40 to form a powder layer group 30. Specifically, the first layer of electrode dry powder 10, the current collector powder 20 and the second layer of electrode dry powder 10 are stacked and contained in the electrode preparation mold 40 in sequence to form a powder layer group 30.

[0148] Under preset pressure and temperature, the electrode sheet is uniformly extruded from all sides using working medium 50 to prepare mold 40 for a preset time. The preset pressure is 200 MPa, the preset temperature is 150 °C, and the preset time is 20 min.

[0149] Take out the composite tablet 31 from the electrode preparation mold 40.

[0150] A portion of the active layer 11 of the electrode is removed by solvent wiping to expose the current collector layer 21.

[0151] Experimental electrode IV was finally obtained. The measured density of experimental electrode IV was 2.842 g / ml, and based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, resulting in a density of 98% for experimental electrode IV. The theoretical density was calculated from the theoretical density of different components and their mass percentages.

[0152] Comparative Example 4

[0153] This comparative example provides a method for preparing an electrode, which differs from Example 4 in that, under the same conditions, the powder layer 30 is pressed using a roller pressing method. Comparative electrode IV is obtained.

[0154] The measured density of the control electrode IV was 2.03 g / ml. Based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, and the density of the control electrode IV was 70%.

[0155] Example 5

[0156] This embodiment provides a method for preparing an electrode sheet, as shown in Figures 1 to 5. The preparation method includes:

[0157] Obtain electrode dry powder 10. Mix the dry powder, which is composed of silicon carbide, polytetrafluoroethylene (PTFE) and conductive carbon black. Mix 94% silicon carbide and 2% conductive carbon black, then add 4% PTFE. After ball milling and high-speed stirring, electrode dry powder 10 is obtained.

[0158] Aluminum powder is ball-milled and stirred at high speed to obtain current collector powder 20.

[0159] The electrode dry powder 10 and the current collector powder 20 are stacked and contained in the electrode preparation mold 40 to form a powder layer group 30. Specifically, the first layer of electrode dry powder 10, the current collector powder 20 and the second layer of electrode dry powder 10 are stacked and contained in the electrode preparation mold 40 in sequence to form a powder layer group 30.

[0160] Under preset pressure and temperature, the electrode sheet is uniformly extruded from all sides using working medium 50 to prepare mold 40 for a preset time. The preset pressure is 200 MPa, the preset temperature is 150 °C, and the preset time is 30 min.

[0161] Take out the composite tablet 31 from the electrode preparation mold 40.

[0162] Mechanical polishing is used to remove part of the active layer 11 of the electrode to expose the current collector layer 21.

[0163] Experimental electrode IV was finally obtained. The measured density of experimental electrode IV was 2.813 g / ml, and based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, resulting in a density of 92%. The theoretical density was calculated from the theoretical density of different components and their mass percentages.

[0164] Comparative Example 5

[0165] This comparative example provides a method for preparing an electrode sheet. The difference between this method and Example 5 is that, under the same conditions, the powder layer 30 is pressed using a roller pressing method. A comparative electrode sheet V is obtained.

[0166] The measured density of the control electrode IV was 2.03 g / ml. Based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, and the density of the control electrode V was 70%.

[0167] Example 6

[0168] This embodiment provides a method for preparing an electrode sheet, as shown in Figures 1 to 5. The preparation method includes:

[0169] Obtain electrode dry powder 10. Mix the dry powder, which is composed of silver carbon, polytetrafluoroethylene (PTFE) and conductive carbon black. Mix 92% silver carbon and 6% conductive carbon black, then add 2% PTFE, and then ball mill and high-speed stir to obtain electrode dry powder 10.

[0170] A current collector powder 20 is obtained by ball milling and high-speed stirring of aluminum alloy powder.

[0171] The electrode dry powder 10 and the current collector powder 20 are stacked and contained in the electrode preparation mold 40 to form a powder layer group 30. Specifically, the first layer of electrode dry powder 10, the current collector powder 20 and the second layer of electrode dry powder 10 are stacked and contained in the electrode preparation mold 40 in sequence to form a powder layer group 30.

[0172] Under preset pressure and temperature, the electrode sheet is uniformly extruded from all sides using working medium 50 to prepare mold 40 for a preset time. The preset pressure is 120 MPa, the preset temperature is 50 °C, and the preset time is 5 min.

[0173] Take out the composite tablet 31 from the electrode preparation mold 40.

[0174] A portion of the active layer 11 of the electrode is removed by solvent wiping to expose the current collector layer 21.

[0175] Finally, experimental electrode VI was obtained. The measured density of experimental electrode VI was 2.726 g / ml, and based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, resulting in a density of 94% for experimental electrode VI.

[0176] Comparative Example 6

[0177] This comparative example provides a method for preparing an electrode, which differs from Example 4 in that, under the same conditions, the powder layer 30 is pressed using a roller pressing method. Comparative electrode VI is obtained.

[0178] The measured density of the control electrode VI was 2.03 g / ml. Based on the theoretical density of 2.9 g / ml, the density was calculated as measured density / theoretical density, and the density of the control electrode VI was 70%.

[0179] As can be seen from the above experimental electrode I, experimental electrode II, experimental electrode III, experimental electrode IV, experimental electrode V, experimental electrode VI, and comparative electrode I, comparative electrode II, comparative electrode III, comparative electrode IV, comparative electrode V, and comparative electrode VI, the preparation method of this application allows the battery electrode to be formed in one step, which simplifies the preparation process, improves production efficiency, and reduces production costs. The active layer 11 and the current collector layer 11 of the electrode have high strength and good adhesion, which greatly improves the density and uniformity of the electrode, reduces the generation of defects, and ultimately improves the overall performance of the battery.

[0180] A second aspect of this application provides an electrode preparation mold, which is applied in the above-described preparation method.

[0181] Referring to Figures 1 to 5, the electrode preparation mold 40 includes a mold cover 41 and a mold body 42 that overlap each other. The mold cover and mold body together define a mold cavity 43 for accommodating the powder layer assembly 30. The overall shrinkage rate of the material of the electrode preparation mold 40 is 3% to 80%, which facilitates the rapid and uniform transfer of isostatic pressing pressure and temperature to the powder layer assembly 30. This ensures that the powder layer assembly 30 experiences the same pressure in all directions, thereby forming a composite sheet 31. This ensures that the active layer 11 and the current collector layer 11 have high strength and good adhesion, greatly improving the density and uniformity of the electrode, reducing the generation of defects, and allowing for the selection of ultra-thick electrode preparation as needed.

[0182] In some embodiments, the overall shrinkage rate of the material of the electrode preparation mold 40 is 5% to 75%.

[0183] In some embodiments, the electrode preparation mold 40 is made of at least one of polyimide, polyetheretherketone, polytetrafluoroethylene, polypropylene, polyethylene, and polyvinyl chloride. The mold cover 41 and the mold body 42 can be made of polyetheretherketone, which has good plasticity and an overall shrinkage rate of 15%. This allows for the convenient and uniform transfer of isostatic pressing pressure and temperature to the powder layer group 30, ensuring that the powder layer group 30 experiences the same pressure in all directions, thereby forming a composite sheet 31. This ultimately improves the density and uniformity of the electrode, reduces the generation of defects, and allows for the selection of ultra-thick electrode preparation as needed.

[0184] In some possible embodiments, referring to Figures 1 to 5, the airtightness of the electrode preparation mold 40 is 1E-09 Pa m3 / s to 1E-06 Pa m3 / s. With the mold cover 41 and mold body 42 overlapping each other, a relatively sealed mold cavity 43 is formed, preventing the composite tablet 31 from being contaminated by the working medium 50.

[0185] A third aspect of this application provides a solid-state battery, including an electrode prepared using the above-described preparation method.

[0186] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0187] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing an electrode, comprising: Obtain electrode powder (10); Obtain the current collector powder (20); The electrode dry powder (10) and the current collector powder (20) are stacked to form a powder layer group (30); The powder layer group (30) is subjected to overall pressure holding treatment to obtain composite tablet (31); wherein, the electrode dry powder (10) is formed into electrode active layer (11) after pressure holding treatment, and the current collector powder (20) is formed into current collector layer (21) after pressure holding treatment. Remove a portion of the electrode active layer (11) of the composite tablet (31) to expose the current collector layer (21).

2. The preparation method according to claim 1, wherein the preparation method is used to prepare a positive electrode sheet; The step of obtaining the electrode powder (10) specifically includes: The positive electrode active material, positive electrode electrolyte, positive electrode conductive agent and positive electrode binder are uniformly mixed; the mass ratio of the positive electrode active material, the positive electrode electrolyte, the positive electrode conductive agent and the positive electrode binder is (90-97):(1-3):(0.5-4.5):(0.5-4.5).

3. The preparation method according to claim 2, wherein the positive electrode active material comprises at least one of lithium iron phosphate and ternary lithium; The positive electrode electrolyte includes at least one of sulfide solid electrolyte, oxide solid electrolyte, and halide electrolyte; The positive electrode conductive agent includes at least one of conductive carbon black, carbon nanotubes, graphene, and carbon fiber. The positive electrode binder includes at least one of polytetrafluoroethylene and modified polytetrafluoroethylene.

4. The preparation method according to claim 1, wherein the preparation method is used to prepare a negative electrode sheet; The step of obtaining the electrode powder (10) specifically includes: The negative electrode active material, negative electrode conductive agent and negative electrode binder are uniformly mixed; the mass ratio of the negative electrode material, the negative electrode conductive agent and the negative electrode binder is (90-95):(2-8):(2-8).

5. The preparation method according to claim 4, wherein the negative electrode active material comprises at least one of silver-carbon and silicon-carbon; The conductive agent includes at least one of conductive carbon black, carbon nanotubes, graphene, and carbon fiber. The binder includes at least one of polytetrafluoroethylene and modified polytetrafluoroethylene.

6. According to the preparation method of claim 1, the current collector powder (20) includes at least one of aluminum powder, copper powder, nickel powder, aluminum alloy powder, copper alloy powder and stainless steel powder.

7. The preparation method according to any one of claims 1 to 6, wherein the step of stacking the electrode dry powder (10) and the current collector powder (20) to form a powder layer assembly (30) specifically includes: The first layer of electrode powder (10), the current collector powder (20), and the second layer of electrode powder (10) are stacked sequentially to form the powder layer group (30).

8. The preparation method according to any one of claims 1 to 7, wherein the thickness of the electrode active layer (11) is 50-300 μm; and the thickness of the current collector layer (21) is 5 μm-15 μm.

9. The preparation method according to any one of claims 1 to 8, wherein the electrode dry powder (10) is prepared by electrostatic spraying, extrusion coating or dry powder spraying; and the current collector powder (20) is prepared by electrostatic spraying, extrusion coating or dry powder spraying.

10. The preparation method according to any one of claims 1 to 9, wherein the step of stacking the electrode dry powder (10) and the current collector powder (20) to form a powder layer assembly (30) comprises: The electrode dry powder (10) and the current collector powder (20) are stacked and contained in the electrode preparation mold (40) to form a powder layer group (30); the overall shrinkage rate of the material of the electrode preparation mold (40) is 3% to 80%.

11. The preparation method according to claim 10, wherein the step of performing overall pressure holding treatment on the powder layer group (30) to obtain composite tablet (31) specifically includes: Under a preset pressure and a preset temperature, the electrode preparation mold (40) is uniformly extruded from all sides using a working medium (50) for a preset time. The composite tablet (31) is taken out from the electrode preparation mold (40).

12. The preparation method according to claim 11, wherein the preset pressure is 2 MPa to 3500 MPa; the preset temperature is 15℃ to 1200℃; the preset time is 2 min to 40 min; and the working medium is an ester, water, or an inert gas.

13. The preparation method according to any one of claims 1 to 12, wherein the step of removing a portion of the electrode active layer (11) of the composite tablet (31) to expose the current collector layer (21) specifically includes: The active layer (11) of the electrode is removed by solvent wiping, laser cleaning or mechanical polishing to expose the current collector layer (21).

14. An electrode preparation mold, used in the preparation method according to any one of claims 1 to 13, the electrode preparation mold comprising a mold cover (41) and a mold body (42) that overlap each other, the mold cover and the mold body together defining a mold cavity (43) for receiving the powder layer group (30).

15. The electrode preparation mold according to claim 14, wherein the material of the electrode preparation mold includes at least one of polyimide, polyetheretherketone, polytetrafluoroethylene, polypropylene, polyethylene, and polyvinyl chloride.

16. The electrode preparation mold according to claim 14, wherein the airtightness of the electrode preparation mold is 1E-09Pa m3 / s to 1E-06Pa m3 / s.

17. A solid-state battery, comprising an electrode prepared by any one of claims 1 to 13.

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