All-solid-state battery preparation method and all-solid-state battery

Abstract

The present application relates to an all-solid-state battery preparation method and an all-solid-state battery. The method comprises: S10, stacking a negative electrode, a solid-state electrolyte, and a positive electrode to form a stacked body; S20, sealing the stacked body with a sealing film to form a pressure-retaining member; and S30, using a first preset pressure to uniformly press the pressure-retaining member from all sides for 1-60 minutes, wherein the first preset pressure is 550-1000 MPa. The all-solid-state battery preparation method and the all-solid-state battery in the embodiments of the present application offer the advantage of high density.

Description

Preparation methods of all-solid-state batteries and all-solid-state batteries

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on June 21, 2024, with application number 202410807074X, entitled "Preparation method of all-solid-state battery and all-solid-state battery", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a method for preparing an all-solid-state battery and the all-solid-state battery itself. Background Technology

[0004] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied 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 power battery applications, market demand is also constantly increasing.

[0005] Solid-state batteries, as one of the future development trends of power batteries, have the advantages of high density, high energy density, and good safety. However, due to limitations in manufacturing processes, the density of current solid-state batteries is relatively low, often failing to meet usage requirements and thus affecting energy density.

[0006] Summary of the Invention

[0007] Therefore, it is necessary to provide a method for preparing an all-solid-state battery and an all-solid-state battery itself, addressing the current problem of low density in all-solid-state batteries.

[0008] The first aspect of this application provides a method for preparing an all-solid-state battery, comprising:

[0009] S10, stacking negative electrode, solid electrolyte and positive electrode to form a stack;

[0010] S20. Seal the stacked body with a sealing film to form a pressure-holding component;

[0011] S30. Using a first preset pressure, the pressure-holding component is evenly squeezed from all sides for 1 minute to 60 minutes. The first preset pressure is 550MPa to 1000MPa.

[0012] In one embodiment, S30 is: applying a first preset pressure to the pressure-holding component for 15 minutes, wherein the first preset pressure is 1000 MPa; or, S30 is: applying a first preset pressure to the pressure-holding component for 15 minutes, wherein the first preset pressure is 900 MPa; or, S30 is: applying a first preset pressure to the pressure-holding component for 15 minutes, wherein the first preset pressure is 800 MPa; or, S30 is: applying a first preset pressure to the pressure-holding component for 15 minutes, wherein the first preset pressure is 800 MPa. The pressure is maintained for 15 minutes, and the first preset pressure is 700 MPa; or, S30 is: the pressure-holding component is maintained at the first preset pressure for 15 minutes, and the first preset pressure is 650 MPa; or, S30 is: the pressure-holding component is maintained at the first preset pressure for 15 minutes, and the first preset pressure is 600 MPa; or, S30 is: the pressure-holding component is maintained at the first preset pressure for 15 minutes, and the first preset pressure is 550 MPa.

[0013] In one embodiment, S30 uses a warm isostatic pressing process to perform the pressing.

[0014] In one embodiment, S30 includes: uniformly pressing the pressure-holding member from all sides using a working medium; the working medium is heat-conducting oil or water.

[0015] In one embodiment, S30 is performed at a preset temperature; the preset temperature is 80°C to 200°C.

[0016] In one embodiment, after S30, the method further includes: S40, tearing off the sealing film on the pressure-holding member to restore it to a stack.

[0017] In one embodiment, after S10, the following step is taken: S11, pre-compressing the stacked body with a second preset pressure for 30 to 120 seconds, wherein the second preset pressure is 5 MPa to 10 MPa.

[0018] In one embodiment, the negative electrode uses at least one of pure lithium, lithium metal composite oxide, and lithium alloy as the negative electrode current collector.

[0019] In one embodiment, the solid electrolyte includes at least one of sulfide solid electrolytes, oxide solid electrolytes, and organic solid electrolytes.

[0020] In one embodiment, the positive electrode uses at least one of stainless steel, aluminum, nickel, titanium, and aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver as the positive electrode current collector.

[0021] In one embodiment, an aluminum-plastic film is used for sealing in step S20.

[0022] A second aspect of this application provides an all-solid-state battery, which is prepared using the above-described preparation method.

[0023] The beneficial effects are as follows: The method for preparing an all-solid-state battery according to the present application involves setting up S10, stacking a negative electrode, a solid electrolyte, and a positive electrode to form a stack; S20, sealing the stack with a sealing film to form a pressure-holding component; S30, using a first preset pressure to uniformly squeeze the pressure-holding component from all sides, avoiding the situation in related technologies where the stack can only be squeezed from both sides, making the squeezing more uniform, and preventing the negative electrode, solid electrolyte, or positive electrode from being damaged due to excessive pressure. Finally, in S30, the pressure-holding component is pressed, and the working medium uniformly squeezes the pressure-holding component from all sides, thereby obtaining an all-solid-state battery with higher density.

[0024] 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

[0025] 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:

[0026] Figure 1 is a flowchart of a method for preparing an all-solid-state battery according to some embodiments of this application.

[0027] Figure 2 is a flowchart of a method for preparing an all-solid-state battery according to other embodiments of this application. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] In the description of the embodiments of this application, if the technical terms "first" or "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.

[0031] In this document, the reference to "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.

[0032] 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, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0033] 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).

[0034] In the description of the embodiments of this application, if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "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 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.

[0035] 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.

[0036] 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," "under," and "below" 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.

[0037] 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.

[0038] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also widely applied 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 power battery applications, market demand is also constantly increasing.

[0039] Solid-state batteries, as one of the future development trends of power batteries, have advantages such as high density, high energy density, and good safety. With the technological development of solid-state batteries, higher requirements are being placed on their density. In related technologies, solid-state batteries use a hot press to hot-press stacked bare cells, resulting in bare cells with uniform height and temperature after being hot-pressed by a hot press plate. However, this method uses resistance wire heating for the hot press plate, and the surface pressure is often only about 3 MPa to 7 MPa. Further increasing the surface pressure can lead to crushing and uneven thickness due to thinning areas at the edges of the electrode sheets caused by coating. Excessive local surface pressure or incomplete compaction of thinned areas during hot pressing affects the cell's safety performance. These limitations mean that solid-state batteries often require lower holding pressures, resulting in lower density and impacting their performance.

[0040] To alleviate the problem of low density in all-solid-state batteries, the outer surface of the stack formed by the negative electrode, solid electrolyte, and positive electrode can be sealed with a film in the design. This avoids the situation where the stack can only be squeezed from both sides, making the compression more uniform. It can also prevent the negative electrode, solid electrolyte, or positive electrode from being damaged due to excessive pressure. As a result, greater pressure can be applied to the negative electrode, solid electrolyte, or positive electrode, thereby obtaining an all-solid-state battery with higher density.

[0041] This application provides a method for preparing an all-solid-state battery and the all-solid-state battery itself. The all-solid-state battery can provide electrical energy to or store electrical energy in an electrical device. The electrical device can be, but is 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.

[0042] The all-solid-state battery in this application typically includes: a negative electrode, a solid electrolyte, and a positive electrode.

[0043] Among them, the negative electrode includes a negative electrode current collector and a negative electrode active material, and the negative electrode active material is coated on the negative electrode current collector. The negative electrode current collector can use at least one of pure lithium, a lithium alloy, and a lithium metal composite oxide. The lithium alloy may include any one or more of aluminum (Al), magnesium (Mg), potassium (K), sodium (Na), calcium (Ca), strontium (Sr), barium (Ba), silicon (Si), germanium (Ge), antimony (Sb), lead (Pb), indium (In), and zinc (Zn). The lithium metal composite oxide may include a composite of lithium and an oxide (MeO x ) of any one metal (Me) selected from silicon (Si), tin (Sn), zinc (Zn), magnesium (Mg), cadmium (Cd), cerium (Ce), nickel (Ni), tungsten (W), and iron (Fe). For example, the lithium metal composite oxide may be Li x Fe2O3 (0 < x ≤ 1) or Li x WO2 (0 < x ≤ 1).

[0044] The negative electrode current collector of the embodiment of the present application may have a protective layer, just like the negative electrode current collector used in a conventional secondary battery using an electrolyte solution. The protective layer may include any material as long as the material has lithium ion conductivity, does not interfere with the operation of the battery, and does not react with lithium. For example, a ceramic protective layer, a lithiated polyacrylic acid protective layer, etc. may be provided. The negative electrode current collector of the embodiment of the present application may use any protective layer as long as the protective layer improves the safety of the negative electrode current collector.

[0045] In addition, pure lithium or a pure lithium alloy may be used as the negative electrode current collector in the embodiment of the present application, or the negative electrode active material may be coated on the negative electrode current collector and dried for use.

[0046] In the all-solid-state battery of the embodiment of the present application, the negative electrode current collector may be formed to have a thickness of 2 micrometers (μm) to 1000 micrometers (μm). In order to increase the bonding force between the negative electrode current collector and the negative electrode active material or the solid electrolyte, a micro-sized concavo-convex structure may be formed on the surface of the negative electrode current collector, and the negative electrode current collector may be configured in any one of various forms (such as a film, sheet, foil, net, porous body, foam body, or non-woven fabric body).

[0047] The above-mentioned negative electrode active material may use carbon (for example, non-graphitized carbon or graphite-like carbon), lithium metal, a lithium alloy, a silicon-based alloy, a tin-based alloy, a conductive polymer (such as polyacetylene), a metal oxide (such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, or Bi2O5) material, a metal composite oxide (such as Li x Fe2O3 (0 ≤ x ≤ 1), Lix WO2(0≤x≤1), Sn x Me 1-x Me' y O z 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, and halogens.

[0048] Solid electrolytes may include at least one of sulfide solid electrolytes, oxide solid electrolytes, and organic solid electrolytes.

[0049] Sulfide-based solid electrolytes possess high lithium-ion conductivity of 10⁻² S / cm to 10⁻³ S / cm, readily forming a contact interface between the electrode and the electrolyte, and exhibiting high mechanical strength and flexibility. In this application, there are no particular limitations on the type of sulfide-based solid electrolyte, and all known sulfide materials used in the battery field are acceptable. In this application, the sulfide-based solid electrolytes include Li₆PS₅Cl (LPSCl) and Thio-LISICON (Li₂S₅Cl). 3.25 Ge 0.25 P 0.75 S4), Li2S-P2S5-LiCl, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5, Li3PS4, Li7P3S 11 , LiI-Li2S-B2S3, Li3PO4-Li2S-Si2S, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, Li 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 and Li7P3S 11 .

[0050] Oxide-based solid 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 electrolytes. Furthermore, oxide-based solid electrolytes exhibit high electrochemical safety and mechanical strength. However, they also have high oxidation voltages. Additionally, solid electrolytes have high grain boundary resistance, making it difficult to form a contact interface between the electrode and the electrolyte, requiring high-temperature heat treatment processes of 1000°C or higher, and these processes are difficult to scale up. In the embodiments of this application, the oxide-based solid electrolyte can be any known oxide material used in the field of lithium batteries. In the embodiments of this application, the oxide-based solid electrolyte includes perovskite solid electrolytes, sodium superionic conductor solid electrolytes (NASICON), lithium superionic conductor solid electrolytes (LISICON), and lithium lanthanum zirconium oxide solid electrolytes (LLZO).

[0051] Organic solid electrolytes (OSEs) are a type of solid electrolyte. OSEs can readily form electrode interfaces and minimize dendrite growth, thus ensuring stable reactions between OSEs and lithium metal. The disadvantages of OSEs are their relatively low lithium-ion conductivity and the fact that they typically require high-temperature operation. In this embodiment, the OSE comprises polyethylene oxide (PEO).

[0052] The thickness of the solid electrolyte can be selected differently depending on the desired properties of the all-solid-state battery. Specifically, in some embodiments, the thickness of the solid electrolyte can be from 0.1 μm to 1000 μm; in other embodiments, the thickness of the solid electrolyte can be from 1 μm to 500 μm; in still other embodiments, the thickness of the solid electrolyte can be from 20 μm to 30 μm; this application does not limit it in this regard.

[0053] For ease of subsequent description and understanding, the preparation method of the all-solid-state battery and the all-solid-state battery in the embodiments of this application can use sulfide-based solid electrolytes.

[0054] The positive electrode in this application typically includes a positive current collector and a positive active layer, with the positive active layer coated on one side surface of the positive current collector. In some embodiments, at least one side surface of the positive current collector includes a central active material region and a blank region surrounding the central active material region, with the positive active layer disposed in the central active material region.

[0055] The positive electrode active layer includes a positive electrode active material, a conductive agent, and a binder; the positive electrode active material includes a positive electrode active substrate and a coating layer on the surface of the positive electrode active substrate, and the coating layer includes an ion conductor material.

[0056] Specifically, the general chemical formula of the positive electrode active substrate includes LiNi. x Coy MzO2, 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.

[0057] 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). It 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.

[0058] The thickness of the coating layer is from 1 nanometer (nm) to 10 nanometers (nm). In one embodiment, the thickness of the coating layer 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 above-mentioned suitable coating thickness enables the positive electrode active material to have excellent electrochemical performance.

[0059] The conductive agents in the embodiments of this application can 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) can be used as conductive agents.

[0060] A binder is a component that facilitates the bonding between the positive electrode active material and the conductive agent, and the bonding with the positive electrode current collector. Based on the total weight of the complex including the positive electrode active material, the binder is typically added in an amount from 0.1 to 30% by weight. In the embodiments of this application, the binder is not particularly limited, and any known binder can be used. For example, the binder can be any one or a mixture of two or more selected from the group consisting of 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.

[0061] In the embodiments of this application, at least one of stainless steel, aluminum, nickel, titanium, and aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver is used as the positive electrode current collector.

[0062] The thickness of the positive electrode current collector can be controlled within the range of 2μm to 1000μm. The materials used to make the positive electrode current collector are generally not limited, as long as they can ensure that the positive electrode current collector has good conductivity and does not react with other substances in the all-solid-state battery using the positive electrode current collector.

[0063] In this embodiment, the positive electrode current collector can be made of stainless steel, aluminum, nickel, or titanium. In other embodiments, the positive electrode current collector can be made of aluminum or stainless steel with a surface treated with carbon, nickel, titanium, or silver. Micro-sized uneven structures can be formed on the surface of the positive electrode current collector to increase adhesion to the positive electrode active mixture. The positive electrode current collector can be configured in any of various forms (e.g., membrane, sheet, foil, mesh, porous body, foam, or nonwoven fabric).

[0064] Referring to Figure 1, which is a flowchart of a method for fabricating an all-solid-state battery according to some embodiments of this application, the first aspect of this application provides a method for fabricating an all-solid-state battery, the method comprising:

[0065] S10, stack the negative electrode, solid electrolyte and positive electrode to form a stack.

[0066] S20. Seal the stacked body with a sealing film to form a pressure-holding component.

[0067] S30. Using the first preset pressure, the pressure-holding component is evenly squeezed from all sides for 1 minute to 60 minutes. The first preset pressure is 550 MPa to 1000 MPa.

[0068] In S10, the negative electrode, solid electrolyte, and positive electrode are stacked and pre-pressed to form a stack. In S20, the stack is sealed with a sealing film to form a pressure-holding component. Specifically, an aluminum-plastic film can be used for sealing. As a stable composite film, the aluminum-plastic film has extremely high barrier properties, good stamping formability, puncture resistance, electrolyte stability, and good insulation. In this way, the outer surface of the stack formed by the negative electrode, solid electrolyte, and positive electrode can be sealed with a sealing film, avoiding the situation in related technologies where the stack can only be squeezed from both sides. This makes the squeezing more uniform and can prevent the negative electrode, solid electrolyte, or positive electrode from being damaged due to excessive pressure. Finally, in S30, the pressure-holding component is pressed, and the working medium squeezes the pressure-holding component evenly from all sides, thereby obtaining a higher density all-solid-state battery.

[0069] Among them, S30 can be pressed using a warm isostatic pressing process.

[0070] The isostatic pressing process utilizes Pascal's principle, placing a pressure-holding component sealed in a flexible mold into a high-pressure cylinder filled with a working medium. High-pressure equipment applies a certain pressure to the working medium in the cylinder, and the pressure is transmitted evenly to the pressure-holding component through the working medium. Under the action of isostatic pressure, the pressure-holding component undergoes a certain volume deformation, thereby achieving isostatic pressing. This allows the pressure-holding component to further improve its density, thus providing higher energy density and meeting the requirements of all-solid-state batteries.

[0071] Specifically, the pressure-holding component is placed inside a sealed high-pressure container. At a preset temperature and a first preset pressure, the pressure-holding component is uniformly compressed from all sides using a working medium. This further increases the density of the pressure-holding component, thereby providing higher energy density to meet the requirements of all-solid-state batteries. The working medium is heat-conducting oil or water; the preset temperature is 80℃~200℃; and the first preset pressure is 550MPa~1000MPa.

[0072] In addition, the S30 can be pressed using a cold isostatic pressing process.

[0073] In the cold isostatic pressing process, the pressure-holding component is placed in packaging material (e.g., laminate), a vacuum is drawn, and then pressed down using cold isostatic pressing. Specifically, a powder-type stacking mold is used outside the high-pressure vessel. The mold is placed directly in the working medium inside the high-pressure vessel, and uniform isostatic pressure is applied to the outer surface of the mold to press the stack. For pressing, a material that does not react with lithium metal or sulfide-based solid electrolytes can be used as the working medium.

[0074] For ease of description, in the embodiments of this application, S30 uses a warm isostatic pressing process to perform the pressing.

[0075] In some possible embodiments, referring to Figures 1 and 2, the method for preparing an all-solid-state battery further includes: S40, peeling off the sealing film on the pressure-holding component to restore it to a stack.

[0076] S40 occurs after S30, where the sealing film on the pressure-holding component is removed to restore the stack, thus facilitating subsequent production processes on the stack.

[0077] In some possible embodiments, referring to Figures 1 and 2, the method for preparing an all-solid-state battery further includes: S11, pre-pressing the stacked body with a second preset pressure for 30 to 120 seconds, wherein the second preset pressure is 5 MPa to 10 MPa.

[0078] S11 is located between S10 and S20. After S10 is completed, the stack is pre-pressed using the second preset pressure. This pre-presses the stack to remove gaps between parts, making it compact for easy sealing, and then proceeds with the subsequent isostatic pressing process.

[0079] To better illustrate the good density of the all-solid-state battery in the embodiments of this application, the following experimental data of several embodiments are provided.

[0080] Example 1

[0081] First, the negative electrode, solid electrolyte, and positive electrode are stacked to form a stack.

[0082] At this time, pure lithium is used as the negative electrode. In addition, a sulfide-based solid electrolyte containing lithium phosphorus sulfide chloride (LPSCl) is used as the solid electrolyte, and a positive electrode slurry obtained by mixing LiNi0.8Co0.1Mn0.1O2 (nickel:cobalt:manganese = 8:1:1, GSEM, GL80) is used as the nickel-cobalt-manganese positive electrode active material. Carbon black, polyvinylidene fluoride (PVDF) and N-methyl-2-pyrrolidone (NMP) are coated on aluminum foil at a weight ratio of 97:1.5:11.5 to a thickness of 20 μm to serve as the positive electrode.

[0083] After performing S10 and S20, measure the length and width of the pressure-holding component.

[0084] In an environment of 150℃, execute S30, specifically, pressurize the pressure holding component with the first preset pressure for 15 minutes. The first preset pressure is 650MPa.

[0085] After completing S30, remeasure the length and width of the pressure-holding component.

[0086] Table (1)

[0087] Refer to Table 1, which illustrates a comparison of the length and width dimensions of each pressure-holding component in test groups 1 to 8 before and after execution of S30.

[0088] Wherein, B1 is the original length of the pressure holding component before S30 is executed; B2 is the length of the pressure holding component after S30 is executed; C1 is the original width of the pressure holding component before S30 is executed; and C2 is the width of the pressure holding component after S30 is executed.

[0089] The length shrinkage rate is (B1-B2) / B1*100%; the width shrinkage rate is (C1-C2) / C1*100%. Table 1 shows that after holding the pressure at 650 MPa for 15 minutes, the length shrinkage rate of the holding component is 1.76%–6.99%, and the width shrinkage rate is 1.96%–8.24%. This demonstrates that the holding component can effectively improve density under higher pressure, thereby ensuring the performance of the all-solid-state battery.

[0090] Example 2

[0091] First, the negative electrode, solid electrolyte, and positive electrode are stacked to form a stack. In this case, the materials used in Example 2 are the same as those in Example 1.

[0092] Then, after performing S10 and S20, measure the thickness of the pressure-holding component.

[0093] At a temperature of 150℃, the pressure-holding components were divided into a first control group, a second control group, and a third control group, and S30 was performed on each group. The first control group, the second control group, and the third control group all had pressure-holding components numbered 1# to 10#.

[0094] Specifically, the first control group: the pressure holding component was pressurized at a first preset pressure for 15 minutes, with the first preset pressure being 550 MPa. The second control group: the pressure holding component was pressurized at a first preset pressure for 15 minutes, with the first preset pressure being 600 MPa. The third control group: the pressure holding component was pressurized at a first preset pressure for 15 minutes, with the first preset pressure being 650 MPa.

[0095] After S30 is completed, remeasure the thickness of the pressure-holding component.

[0096] Table (2)

[0097] Referring to Table 2, which is a comparison table showing the thickness dimensions of each pressure-holding component in the first control group, the second control group, and the third control group before and after performing S30.

[0098] As can be seen from Table 2, the thickness shrinkage rate of the holding component changes after holding under different pressures, and is directly proportional to the magnitude of the first preset pressure. The holding component can effectively shrink its size under a higher first preset pressure, thereby effectively improving the density and ensuring the performance of the all-solid-state battery.

[0099] Example 3

[0100] First, the negative electrode, solid electrolyte, and positive electrode are stacked to form a stack. In this case, the materials used in Example 3 are the same as those in Example 1.

[0101] Then, after performing S10 and S20, measure the thickness of the pressure-holding component.

[0102] At an ambient temperature of 100℃, the pressure-holding components were divided into four control groups (fourth, fifth, sixth, and seventh) and S30 was performed on each group. All four control groups (fourth, fifth, sixth, and seventh) contained pressure-holding components ranging from #11 to #20.

[0103] Specifically, the fourth control group: the pressure-holding component was pressurized at a first preset pressure of 700 MPa for 15 minutes. The fifth control group: the pressure-holding component was pressurized at a first preset pressure of 800 MPa for 15 minutes. The sixth control group: the pressure-holding component was pressurized at a first preset pressure of 900 MPa for 15 minutes. The seventh control group: the pressure-holding component was pressurized at a first preset pressure of 1000 MPa for 15 minutes.

[0104] After S30 is completed, remeasure the thickness of the pressure-holding component.

[0105] Table (3)

[0106] Table 3 is a comparison table showing the thickness dimensions of each pressure-holding component in the fourth, fifth, sixth, and seventh control groups before and after performing S30.

[0107] As shown in Table 3, the thickness shrinkage rate of the holding component changes after holding under different pressures, and is directly proportional to the magnitude of the first preset pressure. Under higher first preset pressures, the holding component can effectively shrink in size, thereby effectively improving density and ensuring the performance of the all-solid-state battery. Combining Tables 1, 2, and 3, the effect of temperature decreasing from 150℃ to 100℃ on the dimensional shrinkage rate is relatively small. With increasing first preset pressure, the holding component can further shrink in size under higher pressure, thereby effectively improving its density and ensuring the performance of the all-solid-state battery.

[0108] Example 4

[0109] First, the negative electrode, solid electrolyte, and positive electrode are stacked to form a stack. In this case, the materials used in Example 4 are the same as those in Example 1.

[0110] Then, after executing S10 and S20, measure the length and width of the pressure-holding component.

[0111] In an environment of 100°C, execute S30, specifically, pressurize the pressure holding component with the first preset pressure for 15 minutes. The first preset pressure is 1000MPa.

[0112] After completing S30, remeasure the length and width of the pressure-holding component.

[0113] Table (4)

[0114] Table 4 is a comparison table showing the length and width dimensions of each pressure-holding component in test groups 9 to 16 before and after execution of S30.

[0115] Wherein, B3 is the original length of the pressure-holding component before S30 is executed; B4 is the length of the pressure-holding component after S30 is executed; C3 is the original width of the pressure-holding component before S30 is executed; and C4 is the width of the pressure-holding component after S30 is executed.

[0116] The length shrinkage rate is (B3-B4) / B3*100%; the width shrinkage rate is (C3-C4) / C3*100%. Table 4 shows that after holding the pressure at 650 MPa for 15 minutes, the length shrinkage rate of the holding component is 7.02%–11.49%, and the width shrinkage rate is 7.38%–10.16%. This demonstrates that the holding component can effectively improve density under higher pressure, thereby ensuring the performance of the all-solid-state battery.

[0117] As can be seen from Tables 4 and 1, the thickness shrinkage rate of the holding component changes after holding under different pressures, and is directly proportional to the magnitude of the first preset pressure. The holding component can effectively shrink its size under a higher first preset pressure, thereby effectively improving the density and ensuring the performance of the all-solid-state battery.

[0118] A second aspect of this application provides an all-solid-state battery, which is manufactured using the above-described preparation method.

[0119] 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.

[0120] 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 all-solid-state battery, comprising: S10, stacking negative electrode, solid electrolyte and positive electrode to form a stack; S20. Seal the stacked body with a sealing film to form a pressure-holding component; S30. Using a first preset pressure, the pressure-holding component is evenly squeezed from all sides for 1 minute to 60 minutes. The first preset pressure is 550MPa to 1000MPa.

2. The preparation method according to claim 1, wherein, S30 is: the pressure holding component is pressure-held under a first preset pressure for 15 minutes, where the first preset pressure is 1000MPa; Alternatively, S30 is: holding the pressure member under a first preset pressure for 15 minutes, wherein the first preset pressure is 900 MPa; Alternatively, S30 is: holding the pressure member under a first preset pressure for 15 minutes, wherein the first preset pressure is 800MPa; Alternatively, S30 is: holding the pressure member under a first preset pressure for 15 minutes, wherein the first preset pressure is 700MPa; Alternatively, S30 is: holding the pressure member under a first preset pressure for 15 minutes, wherein the first preset pressure is 650 MPa; Alternatively, S30 is: holding the pressure member under a first preset pressure for 15 minutes, wherein the first preset pressure is 600MPa; Alternatively, S30 is: holding the pressure member under a first preset pressure for 15 minutes, wherein the first preset pressure is 550 MPa.

3. The preparation method according to claim 1 or 2, wherein, The S30 uses a warm isostatic pressing process to perform the pressing.

4. The preparation method according to claim 1 or 2, wherein, S30 includes: using a working medium to uniformly compress the pressure-holding component from all sides; the working medium is heat-conducting oil or water.

5. The preparation method according to claim 1 or 2, wherein, S30 is performed at a preset temperature; the preset temperature is 80℃~200℃.

6. The preparation method according to claim 1 or 2, wherein, Following S30, it also includes: S40. Remove the sealing film from the pressure-holding member to restore it to a stack.

7. The preparation method according to claim 1 or 2, wherein, After S10, it includes: S11. The stack is pre-compressed using a second preset pressure for 30 to 120 seconds, where the second preset pressure is 5 MPa to 10 MPa.

8. The preparation method according to claim 1 or 2, wherein, The negative electrode uses at least one of pure lithium, lithium metal composite oxide, and lithium alloy as the negative electrode current collector.

9. The preparation method according to claim 1 or 2, wherein, The solid electrolyte includes at least one of sulfide solid electrolytes, oxide solid electrolytes, and organic solid electrolytes.

10. The preparation method according to claim 1 or 2, wherein, The positive electrode uses at least one of stainless steel, aluminum, nickel, titanium, and aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver as the positive electrode current collector.

11. The preparation method according to claim 1 or 2, wherein, In S20, an aluminum-plastic film is used for sealing.

12. An all-solid-state battery, wherein, It is prepared using the preparation method described in any one of claims 1 to 11.

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