Solid-state battery and method of manufacturing the same

Abstract

The application provides a solid-state battery and a preparation method thereof. The solid-state battery provided by the application comprises a battery core, the battery core comprises a positive electrode sheet, a negative electrode sheet and a solid-state electrolyte film between the positive electrode sheet and the negative electrode sheet; the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on at least one side of the positive electrode current collector, and the positive electrode current collector comprises aluminum powder; and the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on at least one side of the negative electrode current collector, and the negative electrode current collector comprises copper powder. The battery core of the solid-state battery provided by the application has low interface impedance, and the solid-state battery has good rate performance and cycle performance.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a solid-state battery and its preparation method. Background Technology

[0002] Solid-state batteries have been widely used in consumer electronics, new energy vehicles and other fields due to their high safety and compact structure.

[0003] However, in commonly used solid-state batteries, the solid interfaces within the internal cells often do not have tight enough contact, resulting in many micropores between the interfaces. This leads to excessively high impedance in the ion transport path, which in turn deteriorates the rate performance and cycle performance of the solid-state battery.

[0004] Therefore, it is urgent to reduce the interface impedance in solid-state battery cells to improve the rate performance and cycle performance of solid-state batteries. Summary of the Invention

[0005] This invention provides a solid-state battery and its fabrication method. The solid-state battery cell has low interfacial impedance, and the solid-state battery exhibits good rate performance and cycle performance.

[0006] This invention provides a solid-state battery, including a cell, the cell including a positive electrode, a negative electrode, and a solid electrolyte membrane located between the positive electrode and the negative electrode;

[0007] The positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector, wherein the positive current collector includes aluminum powder;

[0008] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector, wherein the negative electrode current collector includes copper powder.

[0009] In some embodiments of the present invention, the positive electrode, the solid electrolyte membrane, and the negative electrode are integrally connected;

[0010] And / or, the positive electrode current collector is integrally connected to the positive electrode active material layer;

[0011] And / or, the negative electrode current collector is integrally connected to the negative electrode active material layer;

[0012] And / or, the peel strength between the positive electrode active material layer and the positive electrode current collector is 20 N / 15 mm to 100 N / 15 mm;

[0013] And / or, the peel strength between the negative electrode active material layer and the negative electrode current collector is 10N / 15mm~80N / 15mm.

[0014] In some embodiments of the present invention, the positive electrode, the negative electrode, and the solid electrolyte membrane each independently include a solid electrolyte material.

[0015] In some embodiments of the present invention, the average particle size of the solid electrolyte material is 1 μm to 10 μm;

[0016] And / or, the average particle size of the aluminum powder is 0.5 μm to 50 μm, preferably 0.5 μm to 20 μm;

[0017] And / or, the average particle size of the copper powder is 1μm to 100μm, preferably 5μm to 50μm.

[0018] In some embodiments of the present invention, the positive current collector further includes a positive current collector binder, wherein the mass percentage of the positive current collector binder in the positive current collector is 0.5 wt% to 5 wt%.

[0019] And / or, the negative electrode current collector further includes a negative electrode current collector binder, wherein the negative electrode current collector binder accounts for 0.5wt%~5wt% by mass in the positive electrode current collector;

[0020] And / or, the positive electrode active material layer further includes a positive electrode active material, wherein the positive electrode active material accounts for 70wt%~95wt% of the mass percentage of the positive electrode active material layer, preferably 83wt%~93wt%;

[0021] And / or, the negative electrode active material layer further includes a negative electrode active material, wherein the negative electrode active material accounts for 70wt%~90wt% of the mass percentage of the negative electrode active material layer, preferably 75wt%~90wt%;

[0022] And / or, the thickness of the positive current collector is 3μm~25μm;

[0023] And / or, the thickness of the negative electrode current collector is 2μm~20μm.

[0024] In some embodiments of the present invention, the positive electrode current collector binder includes one or more of polyethylene oxide, polyvinyl alcohol, polyacrylic acid, and styrene-butadiene rubber;

[0025] And / or, the negative electrode current collector binder includes one or more of polyethylene oxide, polyvinyl alcohol, polyacrylic acid, and styrene-butadiene rubber;

[0026] And / or, solid electrolyte materials include one or more of oxide solid electrolyte materials, sulfide solid electrolyte materials, halide solid electrolyte materials, and polymer solid electrolyte materials.

[0027] In some embodiments of the present invention, at least one surface of the battery cell in the thickness direction is provided with a foil, the foil including copper foil;

[0028] And / or, the solid-state battery further includes an electrolyte dispersed in the cell, preferably the electrolyte accounting for 1wt% to 15wt% of the total mass of the cell.

[0029] This invention also provides a method for preparing a solid-state battery as described above, comprising the following steps:

[0030] Step 1) Preparation of negative electrode current collector: This includes spraying a negative electrode current collector slurry containing copper powder onto the surface of a substrate to obtain a negative electrode current collector;

[0031] Step 2) Preparation of negative electrode active material layer: This includes spraying negative electrode slurry onto the surface of the negative electrode current collector on the side away from the substrate to obtain a negative electrode active material layer;

[0032] Step 3) Solid electrolyte membrane preparation: This includes spraying a solid electrolyte slurry onto the surface of the negative electrode active material layer away from the negative electrode current collector to obtain a solid electrolyte membrane;

[0033] Step 4) Preparation of positive electrode active material layer: This includes spraying positive electrode slurry onto the surface of the solid electrolyte membrane opposite to the negative electrode current collector to obtain a positive electrode active material layer;

[0034] Step 5) Preparation of the positive current collector: This includes spraying a positive current collector slurry containing aluminum powder onto the surface of the positive active material layer facing away from the solid electrolyte membrane to obtain a positive current collector and prepare a battery cell.

[0035] Some embodiments of the present invention include the following steps:

[0036] Repeat steps 1) to 5) N times, N≥1;

[0037] After the Nth positive electrode current collector preparation, the method further includes spraying the solid electrolyte slurry onto the surface of the Nth positive electrode active material layer away from the positive electrode current collector to obtain the (N+1)th solid electrolyte membrane; spraying the negative electrode slurry onto the surface of the (N+1)th solid electrolyte membrane away from the positive electrode active material layer to obtain the (N+1)th negative electrode active material layer; and then spraying the negative electrode current collector slurry including copper powder onto the surface of the (N+1)th negative electrode active material layer away from the negative electrode active material layer to obtain the (N+1)th negative electrode current collector, thus preparing a battery.

[0038] In some embodiments of the present invention, the substrate comprises copper foil;

[0039] And / or, the sprayed product must be dried after each spraying step;

[0040] And / or, after obtaining the N+1th negative current collector, a cell precursor is obtained, which also includes sequentially encapsulating the cell precursor and injecting electrolyte.

[0041] In the solid-state battery and its preparation method provided by the present invention, the contact between solid interfaces in the solid-state battery cell is improved by using a spraying process, thereby reducing the interface impedance and improving the rate performance and cycle performance of the solid-state battery. Attached Figure Description

[0042] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0043] Figure 1 This is a schematic diagram of the battery cell structure provided in an embodiment of the present invention;

[0044] Figure 2 This is a line graph showing the rate performance of Embodiment 1 and Comparative Example 1 of the present invention;

[0045] Figure 3 The graphs show the cycle performance of Embodiment 1 and Comparative Example 1 of the present invention.

[0046] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] Currently, solid-state battery cells still suffer from poor interfacial contact and excessively high impedance. The inventors analyzed that the reasons for these problems are: the interfacial tension between the solid electrolyte and electrode materials in existing technologies is relatively high, making it difficult for the solid electrolyte to penetrate into the porous structure of the electrode, resulting in discontinuous ion transport paths and excessively high impedance. Furthermore, existing technologies for solid-state battery cell fabrication often employ a process of separate fabrication followed by assembly. This involves separately fabricating the positive electrode, negative electrode, and solid electrolyte membrane, and then stacking them using methods such as hot pressing. In this process, the surfaces of both the electrode materials and the solid electrolyte membrane have numerous uneven microstructures, preventing tight adhesion between the stacked interfaces and leaving many tiny gaps, significantly increasing interfacial impedance. Simultaneously, this process often uses aluminum or copper foil as current collectors, which have weak interfacial bonding between their surfaces and the electrode active material layers, further exacerbating the high interfacial impedance problem. These excessively high impedance issues deteriorate the rate performance and cycle performance of solid-state batteries.

[0049] Therefore, the inventors started by reducing the interface impedance in solid-state battery cells, attempting to improve the rate performance and cycle performance of solid-state batteries.

[0050] Based on this, embodiments of the present invention provide a solid-state battery, including a cell, the cell including a positive electrode, a negative electrode, and a solid electrolyte membrane located between the positive electrode and the negative electrode; the positive electrode includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector, the positive current collector including aluminum powder; the negative electrode includes a negative current collector and a negative active material layer disposed on at least one side of the negative current collector, the negative current collector including copper powder.

[0051] The solid-state battery of this invention has a low interface impedance inside the cell, which can improve the rate performance and cycle performance of the solid-state battery.

[0052] In detail, in this embodiment of the invention, the positive electrode, negative electrode, and solid electrolyte membrane together constitute the battery cell, serving as the core structure for constructing a solid-state battery. In the positive electrode, the positive active material layer provides electrochemical active sites for the solid-state battery, ensuring its cycle performance and rate performance. The positive current collector, as the core carrier for ion conduction on the positive electrode side, can construct an efficient ion transport pathway within the positive electrode. When the positive current collector includes aluminum powder, it can form a tight interfacial bond with the positive active material layer, reducing interfacial porosity and lowering interfacial impedance, thereby improving the rate performance and cycle performance of the solid-state battery. Similarly, in the negative electrode, the negative active material layer provides electrochemical active sites for the solid-state battery, ensuring its cycle performance and rate performance. The negative current collector, as the core carrier for ion conduction on the negative electrode side, can construct an efficient ion transport pathway within the negative electrode. When the negative current collector includes copper powder, it also achieves a tight interfacial bond with the negative active material layer, reducing interfacial porosity and lowering interfacial impedance, thereby improving the rate performance and cycle performance of the solid-state battery. In addition, when the positive electrode current collector includes aluminum powder, it can have more contact interfaces with the positive electrode active material layer. Similarly, when the negative electrode current collector includes aluminum powder, it can effectively improve the ionic conductivity inside the battery and reduce the internal resistance of the battery. Therefore, it is beneficial to improve the rate performance and cycle performance of the battery.

[0053] In this embodiment of the invention, the positive electrode, solid electrolyte membrane, and negative electrode are integrally connected (i.e., the three are integrated into a single structure, with the positive current collector and the positive active material layer, and the negative current collector and the negative active material layer also being integrally connected). Specifically, under scanning electron microscopy (SEM) cross-sectional observation, each functional layer exhibits a continuous transitional morphology, with no obvious porosity, debonding, or phase separation. Elemental surface scanning (EDS mapping) shows that key elements (such as transition metals in the positive electrode, Na⁺ / Li⁺ conductive framework elements in the electrolyte, and carbon or alloying elements in the negative electrode) are gradient-distributed or interpenetrated in the interface region, indicating the formation of chemical bonds or strong interaction interfaces. Furthermore, when the battery in this embodiment of the invention has the above-mentioned integrated connection structure, the positive electrode, solid electrolyte membrane, and negative electrode cannot be completely separated by conventional external force peeling methods.

[0054] Specifically, in this embodiment of the invention, the positive electrode current collector and the positive electrode active material layer are integrally connected (i.e., the two are an integrally connected structure), which is beneficial to further reduce the internal resistance of the battery and further improve the rate performance and cycle performance of the battery. A detailed description of the integral connection is given above and will not be repeated here.

[0055] In some embodiments, the negative electrode current collector and the negative electrode active material layer are integrally connected (i.e., they are an integrated connection structure), which helps to further reduce the battery's internal resistance and further improve the battery's rate performance and cycle performance. A detailed description of the integrated connection is given above and will not be repeated here.

[0056] The special integrated structure described above in this embodiment of the invention requires special processes (such as spraying methods) and special compositions of positive and negative current collectors, rather than structures formed by conventional coating methods.

[0057] In some embodiments of the present invention, the peel strength between the positive electrode active material layer and the positive electrode current collector is 20 N / 15 mm to 100 N / 15 mm, which can further improve the rate performance of the solid-state battery. For example, the peel strength between the positive electrode active material layer and the negative electrode current collector is in the range of 20 N / 15 mm, 40 N / 15 mm, 60 N / 15 mm, 80 N / 15 mm, 100 N / 15 mm, or any combination thereof.

[0058] In some embodiments, the peel strength between the negative electrode active material layer and the negative electrode current collector is 10 N / 15 mm to 80 N / 15 mm, which can further improve the rate performance of the solid-state battery. For example, the peel strength between the negative electrode active material layer and the negative electrode current collector is in the range of 10 N / 15 mm, 20 N / 15 mm, 40 N / 15 mm, 60 N / 15 mm, 80 N / 15 mm, or any combination thereof.

[0059] This invention provides an embodiment for testing the peel strength between the positive electrode active material layer and the positive electrode current collector, and the peel strength between the negative electrode active material layer and the negative electrode current collector of a solid-state battery using conventional testing methods and instruments in the art. In one specific embodiment, the peel strength tests for the positive electrode active material layer and the positive electrode current collector, and the peel strength tests for the negative electrode active material layer and the negative electrode current collector of a solid-state battery specifically include the following steps: After the battery is fully discharged, it is disassembled to separate the components including the positive electrode active material layer and the positive electrode current collector, as well as the component including the negative electrode active material layer. The components are then cut (the cut length is determined according to the length of the fixed smooth plate, and the width is 15mm). Taking the peel strength between the positive electrode active layer and the positive electrode current collector as an example, one side of the cut component is adhered to the surface of the positive electrode active material layer opposite to the positive electrode current collector using 3M double-sided tape, and the other side of the 3M double-sided tape is adhered to the fixed smooth plate. A tensile tester is used to clamp the positive electrode current collector and apply a tensile force perpendicular to the surface of the positive electrode current collector. The force changes during the peeling process are recorded using a universal tensile testing machine, and the average peel force per unit width is calculated.

[0060] In some embodiments of the present invention, the positive electrode, negative electrode, and solid electrolyte membrane each independently include a solid electrolyte material. In the above embodiments, by introducing solid electrolyte materials into the positive electrode, negative electrode, and solid electrolyte membrane, the ion transport effect can be further improved in the solid electrolyte membrane, thereby improving the rate performance and cycle performance of the solid-state battery; in the positive and negative electrode, the pores between active material particles can be filled, further reducing interfacial tension and more effectively reducing interfacial impedance, further improving the rate performance and cycle performance of the solid-state battery.

[0061] In some embodiments of the present invention, the average particle size of the solid electrolyte material is 1 μm to 10 μm, which is beneficial for further improving the rate performance and cycle performance of the solid-state battery. For example, the average particle size of the solid electrolyte material is, for example, a range of 1 μm, 2 μm, 4 μm, 8 μm, 10 μm, or any combination thereof.

[0062] In some embodiments of the present invention, an average particle size of aluminum powder of 0.5 μm to 50 μm is more conducive to improving the rate performance and cycle performance of solid-state batteries, and preferably an average particle size of 0.5 μm to 20 μm is even more effective. For example, the average particle size of aluminum powder is, for example, a range of 0.5 μm, 1 μm, 1.5 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, or any combination thereof.

[0063] In some embodiments of the present invention, an average particle size of copper powder of 1 μm to 100 μm is more conducive to improving the rate performance and cycle performance of solid-state batteries, and preferably an average particle size of 5 μm to 50 μm is even more effective. For example, the average particle size of copper powder is, for example, a range of 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, or any combination thereof.

[0064] This invention provides embodiments for testing the average particle size of solid electrolyte materials, aluminum powder, and copper powder using conventional testing methods and instruments in the art. In one specific embodiment, the average particle size test includes the following steps: After fully discharging the battery, disassemble it, remove the cell, and peel off the target test layer (positive electrode current collector layer, negative electrode current collector layer, or solid electrolyte film layer). Perform SEM testing on the cross-section obtained by argon ion thinning (CP). Based on the differences in conductivity of different active materials and the different contrast of different particles, perform EDS testing at different locations. Differentiate aluminum powder, copper powder, and solid electrolyte materials based on the differences in elemental content in the EDS, and statistically analyze their average particle size (e.g., at least 50 particles can be analyzed and averaged). Alternatively, a laser particle size analyzer can be used to directly test the average particle size of the corresponding raw materials before battery manufacturing.

[0065] In some embodiments of the present invention, the positive current collector further includes a positive current collector binder, wherein the mass percentage of the positive current collector binder in the positive current collector is 0.5 wt% to 5 wt%. When the positive current collector binder has the above-mentioned mass percentage, it is more beneficial to reduce the interfacial impedance and improve the rate performance and cycle performance of the solid-state battery. For example, the mass percentage is, for example, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, or any combination thereof.

[0066] In some embodiments of the present invention, the negative electrode current collector further includes a negative electrode current collector binder, wherein the mass percentage of the negative electrode current collector binder in the negative electrode current collector is 0.5wt% to 5wt%. When the negative electrode current collector binder has the above-mentioned mass percentage, it is more beneficial to reduce the interfacial impedance and improve the rate performance and cycle performance of the solid-state battery. For example, the mass percentage is, for example, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, or any combination thereof.

[0067] In some embodiments of the present invention, the positive electrode active material layer further includes a positive electrode active material. When the mass percentage of the positive electrode active material in the positive electrode active material layer is 70 wt% to 95 wt%, it is more beneficial to improve the rate performance and cycle performance of the solid-state battery. For example, the mass percentage may be 70 wt%, 80 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 93.5 wt%, 94 wt%, 95 wt%, or any combination thereof. When the mass percentage of the positive electrode active material in the positive electrode active material layer is 83 wt% to 93 wt%, the effect is even better.

[0068] The embodiments of this invention do not impose any particular limitation on the type of positive electrode active material, and any material conventional in the art can be used. Selecting a positive electrode active material containing lithium ions is more effective. For example, the positive electrode active material includes one or more of the following: lithium iron phosphate, nickel-cobalt-manganese ternary positive electrode materials (e.g., 111, 442, 532, 622, 811, 9-series, etc.), lithium manganese oxide, lithium cobalt oxide, lithium manganese iron phosphate, lithium-rich manganese-based materials, and high-voltage nickel-manganese lithium oxide.

[0069] In some embodiments of the present invention, the negative electrode active material layer further includes a negative electrode active material. When the mass percentage of the negative electrode active material in the negative electrode active material layer is 70wt% to 90wt%, it is more beneficial to improve the rate performance and cycle performance of the solid-state battery. For example, the mass percentage may be 70wt%, 80wt%, 90wt%, or any combination thereof. The effect is even better when the mass percentage of the negative electrode active material in the negative electrode active material layer is 75wt% to 90wt%.

[0070] The embodiments of the present invention do not impose any particular limitation on the type of negative electrode active material, which can be conventional materials in the art. For example, the negative electrode active material includes one or more of the following: artificial graphite, natural graphite, lithium titanate, lithium metal, silicon, silicon suboxide, and silicon-carbon composite.

[0071] In some embodiments of the present invention, the positive electrode active material layer may include a conductive agent and a binder, both of which can be conventional materials in the art. For example, the conductive agent may include one or more of carbon black, carbon nanotubes, carbon fibers, graphene, and Ketjen black; the binder may include one or more of polytetrafluoroethylene (PVDF), polyethylene oxide (PEO), polyvinyl alcohol (PVA), and polyacrylic acid (PAA).

[0072] In some embodiments of the present invention, the negative electrode active material layer may include a conductive agent, a binder, and a thickener, all of which can be conventional materials in the art. For example, the conductive agent may include one or more of carbon black, carbon nanotubes, carbon fibers, graphene, and Ketjen black; the binder may include one or more of styrene-butadiene rubber (SBR), polyethylene oxide (PEO), polyvinyl alcohol (PVA), and polyacrylic acid (PAA); and the thickener may include one or more of sodium carboxymethyl cellulose, sodium polyacrylate, carboxymethyl cellulose, and carboxyethyl cellulose.

[0073] In some embodiments of the present invention, the structure of the battery cell is as follows: Figure 1As shown, the battery cell includes a positive electrode, a negative electrode, and a solid electrolyte membrane (PEO material) located between the positive and negative electrode. The positive electrode includes a positive current collector layer and a positive active material layer; the negative electrode includes a negative current collector layer and a negative active material layer. In this embodiment of the invention, PEO can coordinate with active metal ions in the battery cell to form PEO with coordinated active metal ions, which can better improve the rate performance and cycle performance of the battery. When the battery of this embodiment includes the above structure, it can further improve the rate performance, cycle performance, energy density, and safety performance of the battery.

[0074] In some embodiments of the present invention, a positive electrode current collector thickness of 3 μm to 25 μm is more conducive to improving the rate performance and cycle performance of the solid-state battery. For example, the thickness of the positive electrode current collector is, for example, a range of 3 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, or any combination thereof.

[0075] In some embodiments of the present invention, a negative electrode current collector thickness of 2 μm to 20 μm is more conducive to improving the rate performance and cycle performance of the solid-state battery. For example, the thickness of the negative electrode current collector is, for example, a range of 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, or any combination thereof.

[0076] The embodiments of the present invention do not impose special limitations on the thickness of the positive electrode active material layer, the thickness of the solid electrolyte membrane, and the thickness of the negative electrode active material layer, which can be selected according to the actual situation.

[0077] In this embodiment of the invention, the thickness of the positive electrode current collector, negative electrode current collector, positive electrode active material layer, and negative electrode active material layer can be tested using an infrared testing instrument during the battery manufacturing process.

[0078] In some embodiments of the present invention, the positive electrode current collector binder includes one or more of polyethylene oxide, polyvinyl alcohol, polyacrylic acid, and styrene-butadiene rubber. Using the above-mentioned positive electrode current collector binder is more beneficial for reducing interfacial impedance and thus improving the rate performance and cycle performance of the solid-state battery. Furthermore, embodiments of the present invention can directly use polyethylene oxide (PEO) as a binder, which is even more beneficial for reducing interfacial impedance and thus improving the rate performance and cycle performance of the solid-state battery. That is, in embodiments of the present invention, PEO can act as both a solid electrolyte material to coordinate active metal ions and a binder to perform its binding function. In this case, no additional binder needs to be added, which is beneficial for better improving the energy density of the battery.

[0079] In some embodiments of the present invention, the negative electrode current collector binder includes one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyethylene oxide, polyvinyl alcohol, polyacrylic acid, and styrene-butadiene rubber. Using the above-mentioned negative electrode current collector binder is more beneficial for reducing interfacial impedance and thus improving the rate performance and cycle performance of the solid-state battery. Preferably, the negative electrode binder includes polytetrafluoroethylene or polyethylene oxide (PEO), which is more beneficial for reducing interfacial impedance and thus improving the rate performance and cycle performance of the solid-state battery.

[0080] In some embodiments of the present invention, the solid electrolyte material includes one or more of oxide solid electrolyte materials, sulfide solid electrolyte materials, halide solid electrolyte materials, and polymer solid electrolyte materials. By selecting the above-mentioned solid electrolyte materials, the embodiments of the present invention are more conducive to improving the rate performance and cycle performance of solid-state batteries. When the polymer solid electrolyte material includes PEO, the rate performance and cycle performance of the solid-state battery can be further improved.

[0081] In some embodiments of the present invention, the solid electrolyte material includes a polymer solid electrolyte material, which may include a PEO-based solid electrolyte material. The PEO-based solid electrolyte material may include a PEO framework and inorganic fillers filling the PEO framework. In some embodiments of the present invention, the particle size of the inorganic filler may be, for example, 1 nm to 1000 nm. The inorganic filler may be selected from one or more inorganic fillers such as silicon dioxide (SiO2) and titanium dioxide (TiO2). The present invention does not impose specific limitations on the selection of inorganic fillers and can be determined according to actual conditions. Furthermore, the electrolyte in the PEO-based solid electrolyte material may be a modified polyethylene oxide (PEO)-based electrolyte. The modified PEO-based electrolyte uses PEO as the base material and modifies PEO through one or more modification strategies, such as polymer blending and plasticizer addition, to effectively suppress PEO crystallization behavior, further broaden the operating temperature range of the electrolyte, and better improve the ion conductivity and structural stability of the electrolyte over a wide temperature range. The copolymer and plasticizer may be conventional types suitable for lithium-ion battery electrochemical systems.

[0082] In some embodiments of the present invention, at least one surface of the cell in the thickness direction is provided with a foil, the foil including copper foil. In the above embodiments, by providing copper foil in the cell thickness direction, the cell structure can be further supported, which is more conducive to improving the rate performance and cycle performance of the solid-state battery.

[0083] In some embodiments of the present invention, the solid-state battery further includes an electrolyte dispersed in the cell, preferably comprising 1 wt% to 15 wt% of the total mass of the cell. This is beneficial for further reducing the internal resistance of the solid-state battery and improving its rate performance. Specifically, the electrolyte can be immersed in at least one of the following battery components in the cell: the positive electrode current collector, the negative electrode current collector, the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte membrane. For example, the mass percentage of the electrolyte relative to the total mass of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte membrane is, for example, 1 wt%, 5 wt%, 10 wt%, 15%, or any combination thereof.

[0084] The embodiments of the present invention do not impose special limitations on the composition of the electrolyte, which can be selected according to the actual situation.

[0085] The embodiments of this invention can employ conventional testing methods and instruments in the art to test the electrolyte components in solid-state batteries. For example, the solid-state battery can be dried, and the difference in mass before and after drying can be tested to obtain the mass ratio of the electrolyte to the total mass of the battery cell. Furthermore, conventional solvents (such as tetrahydrofuran, methanol, acetonitrile, etc., which can be selected according to actual conditions) can be used to wash the electrolyte out of the solid electrolyte, and then the analysis can be performed using gas chromatography-mass spectrometry (GC-MS), ion chromatography (IC), or high-performance liquid chromatography (HPLC). This invention also provides a method for preparing the above-mentioned solid-state battery, comprising the following steps: Step 1) Preparation of negative electrode current collector: including spraying a negative electrode current collector slurry containing copper powder onto the surface of a substrate to obtain a negative electrode current collector; Step 2) Preparation of negative electrode active material layer: including spraying a negative electrode slurry onto the surface of the negative electrode current collector facing away from the substrate to obtain a negative electrode active material layer; Step 3) Preparation of solid electrolyte membrane: including spraying a solid electrolyte slurry onto the surface of the negative electrode active material layer facing away from the negative electrode current collector to obtain a solid electrolyte membrane; Step 4) Preparation of positive electrode active material layer: including spraying a positive electrode slurry onto the surface of the solid electrolyte membrane facing away from the negative electrode current collector to obtain a positive electrode active material layer; Step 5) Preparation of positive electrode current collector: including spraying a positive electrode current collector slurry containing aluminum powder onto the surface of the positive electrode active material layer facing away from the solid electrolyte membrane to obtain a positive electrode current collector, thereby preparing a battery cell.

[0086] This invention provides an embodiment of a solid-state battery prepared using the aforementioned method. The solid-state battery includes a cell, comprising a positive electrode, a negative electrode, and a solid electrolyte membrane located between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector; the positive current collector comprises aluminum powder. The negative electrode includes a negative current collector and a negative active material layer disposed on at least one side of the negative current collector; the negative current collector comprises copper powder. This invention provides an embodiment of a cell with low interfacial impedance, which is beneficial for improving the rate performance and cycle performance of solid-state batteries.

[0087] In detail, in the above-mentioned preparation process of this invention, the negative electrode current collector, negative electrode active material layer, solid electrolyte membrane, positive electrode active material layer, and positive electrode current collector are sequentially combined by spraying. The continuous spraying method reduces the interfacial porosity between the functional layers and significantly reduces the interfacial impedance for ion migration across the interface, which is beneficial to improving the rate performance and cycle performance of the solid-state battery. In addition, by introducing aluminum powder into the positive electrode current collector and copper powder into the negative electrode current collector, the above-mentioned powdered materials can form a tight interfacial bond with the electrode active material layer, reducing the porosity between the interfaces and lowering the interfacial impedance, thereby improving the rate performance and cycle performance of the solid-state battery.

[0088] Compared to the traditional method of preparing solid-state batteries by coating slurry (sequentially coating the positive electrode slurry and the solid electrolyte slurry), the embodiments of the present invention can prepare a solid-state battery by means of the above-mentioned spraying method, in which the positive electrode sheet, the solid electrolyte membrane, and the negative electrode sheet are integrated, the positive electrode current collector and the positive electrode active material layer are integrated, and the negative electrode current collector and the negative electrode active material layer are integrated. The interface resistance problem inside the solid-state battery cell is further improved, which further reduces the internal resistance of the battery and gives the battery better cycle performance and rate performance.

[0089] In some embodiments of the present invention, the copper foil negative electrode current collector can be used as a substrate, and the negative electrode slurry can be directly sprayed onto one side surface of the copper foil to obtain a negative electrode active material layer. Then, the solid electrolyte membrane, positive electrode active material layer, and positive electrode current collector are prepared sequentially using the above method. After the desired battery cell is finally sprayed, a support material can be covered on the surface in the thickness direction of the battery cell to better adapt to the mechanical requirements of the battery cell in different scenarios. For example, the support material can be foil, and in some embodiments, the support material can be, for example, copper foil, etc., which can be selected according to the actual situation.

[0090] The embodiments of the present invention do not impose any particular restrictions on the specific operation process of spraying, and commonly used spraying tools, spraying time, spraying amount, etc. in the art can be selected.

[0091] In some embodiments of the present invention, the aforementioned negative electrode current collector slurry, negative electrode slurry, solid electrolyte slurry, positive electrode slurry, and positive electrode current collector slurry include a solvent. Including a solvent in the slurry is more conducive to completing the spraying operation of the embodiments of the present invention, and is more conducive to reducing interfacial impedance to improve the cycle performance and rate performance of the resulting solid-state battery.

[0092] The solvents in the aforementioned negative electrode current collector slurry, negative electrode slurry, solid electrolyte slurry, positive electrode slurry, and positive electrode current collector slurry each independently include water, or one or more of the following: ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate (PC), methyl propyl carbonate (MPC), dimethyl carbonate (DMC), acetone, ethanol, polyacrylic acid compounds, aminoamides, dimethyl sulfoxide, thiophosphate, and N,N-dimethylformamide (DMF) (the specific choice can be water or a non-aqueous solvent depending on the actual situation). Using the above solvents is more conducive to improving the cycle performance and rate performance of the prepared solid-state battery.

[0093] The specific selection of the solvent in the embodiments of the present invention can be based on the type of solid electrolyte material. In specific implementation, a suitable solvent is selected by comprehensively considering the dispersibility, chemical inertness, and compatibility with the spraying process of the solid electrolyte material in the solvent, which is more conducive to improving the cycle performance and rate performance of the resulting solid-state battery. For example, when using a sulfide solid electrolyte, one or more of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, methyl propyl carbonate, and dimethyl carbonate can be used as a solvent, which can better improve the stability of the spraying process and is more conducive to improving the cycle performance and rate performance of the resulting solid-state battery. In some embodiments of the present invention, the solid electrolyte material includes a polymer electrolyte material, wherein the polymer electrolyte material includes a PEO (ethylene oxide) polymer solid electrolyte material.

[0094] In some embodiments of the present invention, the above-mentioned negative electrode current collector slurry, negative electrode slurry, solid electrolyte slurry, positive electrode slurry, and positive electrode current collector slurry include additives. Including additives in the above-mentioned slurries is more conducive to completing the spraying operation of the embodiments of the present invention, and is more conducive to reducing interfacial impedance to improve the cycle performance and rate performance of the obtained solid-state battery.

[0095] The embodiments of the present invention do not impose any particular restrictions on the specific preparation process of the negative electrode current collector slurry, negative electrode slurry, solid electrolyte slurry, positive electrode slurry, and positive electrode current collector slurry. The conventional mixing methods and mixing times in the art can be selected according to the composition in the above embodiments.

[0096] In some embodiments of the present invention, drying is performed after each step in the above-described solid-state battery preparation method. Specifically, by drying the sprayed slurry in the above embodiments, the contact between interfaces within the cell can be further enhanced, which is more conducive to reducing interface impedance and improving the cycle performance and rate performance of the resulting solid-state battery.

[0097] The embodiments of the present invention do not impose particular limitations on the specific operation process of the drying treatment, and commonly used drying treatment methods, temperatures, times, etc. in the art can be selected. In one specific embodiment, the battery cell under preparation can be placed in a drying oven after each layer of spraying, and each drying treatment is carried out at 60℃~150℃. The drying treatment can be carried out in an oven.

[0098] In some embodiments of the present invention, during layer-by-layer spraying, a gradient interface structure can be created between the solid electrolyte membrane and the active material layer by spraying slurries of different concentrations, resulting in a gradient change in conductivity and ion transport capability at the interface. For example, the interface region near the active material layer is enriched with conductive agent, while the region near the solid electrolyte membrane is enriched with solid electrolyte material. This gradient interface design further alleviates the mechanical mismatch between the electrode active material layer and the solid electrolyte membrane, further reduces stress concentration at the interface, and further reduces interface impedance through the gradient transition of conductivity and ion transport capability, thus improving the cycle performance and rate performance of the solid-state battery.

[0099] In some embodiments of the present invention, during layer-by-layer spraying, a porous interface material (such as a porous carbon nanotube membrane or porous oxide) can be introduced between the solid electrolyte membrane and the active material layer. This porous structure increases the contact area between the interfaces and provides more ion transport channels. In the above embodiments, the introduction of the aforementioned porous interface material can further enhance the bonding force between the active material layer and the solid electrolyte membrane through physical adsorption. Simultaneously, the porous structure of the interface material can better accommodate the permeation of the solid electrolyte and active material, forming a more continuous ion transport path, and more effectively reducing interfacial impedance to improve the cycle performance and rate performance of the solid-state battery.

[0100] In some embodiments of the present invention, the method for preparing the above-mentioned solid-state battery includes the following steps: repeating steps 1) to 5) N times, N≥1; after the Nth positive electrode current collector preparation, the method further includes spraying a solid electrolyte slurry onto the surface of the Nth positive electrode active material layer away from the positive electrode current collector to obtain the N+1th solid electrolyte membrane; spraying a negative electrode slurry onto the surface of the N+1th solid electrolyte membrane away from the positive electrode active material layer to obtain the N+1th negative electrode active material layer; and then spraying a negative electrode current collector slurry including copper powder onto the surface of the N+1th negative electrode active material layer away from the negative electrode active material layer to obtain the N+1th negative electrode current collector, thereby preparing the battery.

[0101] In other words, the solid-state battery fabrication method of this invention allows for the repeated arrangement of multiple series-connected cell units on one side of the substrate. Furthermore, after the Nth positive electrode current collector fabrication, the (N+1)th solid electrolyte membrane, negative electrode active material layer, and negative electrode current collector can be sequentially sprayed onto the other side of the substrate. This makes the structure of the series-connected stacked cell units more complete, and the electrochemical system of the solid-state battery symmetrical and closed-loop, which is more conducive to improving the cycle performance and rate performance of the fabricated solid-state battery.

[0102] In some embodiments of the present invention, the substrate includes copper foil. By using copper foil as the substrate, the above embodiments can better support the structure of the sprayed cell, further reduce the interfacial impedance between layers, and more effectively improve the cycle performance and rate performance of the resulting solid-state battery.

[0103] In some embodiments of the present invention, a copper foil can be further coated on the surface of the N+1th negative electrode current collector on the side away from the negative electrode active material layer to prepare the above-mentioned battery, so as to further improve the mechanical performance of the battery.

[0104] In some embodiments of the present invention, step 4), after spraying the positive electrode slurry onto the surface of the solid electrolyte membrane opposite to the negative electrode current collector, further includes drying the sprayed product, which is beneficial to further improve the stability of the positive electrode active material layer. The drying method and time can be selected according to the actual situation.

[0105] In some embodiments, after obtaining the (N+1)th negative current collector, a cell precursor is obtained, which further includes sequentially encapsulating the cell precursor and injecting electrolyte. In this embodiment of the invention, the electrolyte accounts for 1wt% to 15wt% of the total mass of the obtained cell. Specifically, after encapsulating the cell precursor, an injection port can be provided, and then the electrolyte can be injected through the injection port. The selection of electrolyte is as described above and will not be repeated here.

[0106] In this embodiment of the invention, the thickness of the positive electrode current collector, the thickness of the negative electrode current collector, the thickness of the positive electrode active material layer, and the thickness of the negative electrode active material layer can be controlled by controlling parameters such as the solid content of the slurry in the spraying process, the spraying speed, and the spraying time.

[0107] In the different spraying steps described above, the spraying parameters can be the same or different, and can be selected according to the actual situation.

[0108] In some embodiments of the present invention, the battery cell may be subjected to a rolling process before encapsulation to further reduce the interface impedance inside the cell and improve the cycle performance and rate performance of the resulting solid-state battery. The embodiments of the present invention do not impose particular limitations on the specific rolling operation process, and commonly used techniques in the art can be selected.

[0109] In some embodiments of the present invention, the battery cell can be packaged using conventional housing materials in the art. The housing may include flexible packaging materials such as aluminum-plastic film, or rigid housing materials such as steel.

[0110] This invention also provides a battery pack comprising at least two of the above-described solid-state batteries.

[0111] Typically, a battery pack comprises multiple solid-state batteries as individual cells, which are connected to form the battery pack. These solid-state batteries can be electrically connected using methods conventional in the art, such as series connection, parallel connection, or a hybrid connection including both of these methods, without any particular limitation.

[0112] This invention also provides an electrical device including the aforementioned solid-state battery.

[0113] The electrical equipment used in the embodiments of the present invention can be conventional electrical equipment in the art, such as power equipment (e.g., electric vehicles, electric cars), electronic equipment (e.g., mobile phones, tablets, laptops, digital cameras, etc.), wearable devices (e.g., watches, bracelets, VR glasses, etc.), energy storage power stations, etc., and there are no particular limitations on this.

[0114] Example 1

[0115] The battery of this invention is prepared by the following method:

[0116] 1) Step 1) Preparation of negative electrode current collector: This includes spraying a negative electrode current collector slurry containing copper powder (including copper powder and PEO dissolved in water at a mass ratio of 99:1) onto the surface of copper foil and drying it at 115°C to obtain the negative electrode current collector;

[0117] Step 2) Preparation of negative electrode active material layer: This includes spraying negative electrode slurry (including negative electrode active materials graphite and PEO, dissolved in solvent water at a mass ratio of 85:15) onto the surface of the negative electrode current collector on the side away from the substrate, and drying it at 115°C to obtain the negative electrode active material layer.

[0118] Step 3) Solid electrolyte membrane preparation: This includes spraying a solid electrolyte slurry (including PEO and solvent acetone, with a solid content of 30%) onto the surface of the negative electrode active material layer away from the negative electrode current collector, and drying it at 60°C to obtain a solid electrolyte membrane.

[0119] Step 4) Preparation of positive electrode active material layer: This includes spraying positive electrode slurry (including positive electrode active materials NCM622, PEO, and conductive agent (specifically carbon black) dissolved in NMP solvent at a mass ratio of 88:9.5:2.5) onto the surface of the solid electrolyte membrane away from the negative electrode current collector, and drying it at 110°C to obtain the positive electrode active material layer.

[0120] Step 5) Preparation of positive current collector: This includes spraying a positive current collector slurry containing aluminum powder (including aluminum powder and PEO dissolved in an aqueous solvent at a mass ratio of 99:1) onto the surface of the positive active material layer away from the solid electrolyte membrane, and drying it at 110°C to obtain the positive current collector.

[0121] Repeat steps 1) through 5) 13 times.

[0122] After the 13th positive electrode current collector preparation, the process further includes spraying a solid electrolyte slurry onto the surface of the 13th positive electrode active material layer away from the positive electrode current collector to obtain the 13th solid electrolyte membrane; spraying a negative electrode slurry onto the surface of the 13th solid electrolyte membrane away from the positive electrode active material layer to obtain the 14th negative electrode active material layer; and then spraying a negative electrode current collector slurry including copper powder onto the surface of the 14th negative electrode active material layer away from the negative electrode active material layer to obtain the 14th negative electrode current collector. The surface of the 14th negative electrode current collector, away from the negative electrode active material layer, is covered with another layer of copper foil to obtain the cell. The cell is then encapsulated using an aluminum-plastic film, with a pre-reserved electrolyte injection port. Electrolyte (10% of the total mass of the cell, with 1 mol / L LiPF6 in the electrolyte; EC / EMC / PC / DEC / VC / PS in a mass ratio of 45:39:5:8:2:1) is injected into the injection port and then sealed to obtain the battery. The battery consists of 13 positive electrode plates and 14 negative electrode plates.

[0123] The average particle size of the solid electrolyte material, the average particle size of the aluminum powder, the average particle size of the copper powder, the mass ratio of the positive current collector binder in the positive current collector, the mass ratio of the negative current collector binder in the positive current collector, the mass ratio of the positive active material in the positive active material layer, the mass ratio of the negative active material in the negative active material layer, the thickness of the positive current collector, the thickness of the negative current collector, the thickness of the positive active material layer, and the thickness of the negative active material layer in this embodiment are shown in Table 1.

[0124] The differences between Examples 2-4 and Example 1 lie in the following parameters: the ratio of the average particle size of the solid electrolyte material to the average particle size of the aluminum powder; the ratio of the average particle size of the solid electrolyte material to the average particle size of the copper powder; the average particle size of the solid electrolyte material; the average particle size of the aluminum powder; the average particle size of the copper powder; the mass percentage of the positive electrode current collector binder in the positive electrode current collector; the mass percentage of the negative electrode current collector binder in the positive electrode current collector; the mass percentage of the positive electrode active material in the positive electrode active material layer (referred to as the positive electrode active material mass percentage in the table); the thickness of the positive electrode current collector; the thickness of the negative electrode current collector; the thickness of the positive electrode active material layer; the thickness of the negative electrode active material layer; and the thickness of the solid electrolyte membrane. See Table 1 for details. When the mass percentages of the positive electrode active material and the negative electrode active material in the negative electrode active material layer change, the increase or decrease in mass is compensated or deducted by PEO accordingly.

[0125] Comparative Example 1

[0126] The difference between this comparative example and Example 1 is that the positive current collector in this comparative example is a conventional aluminum foil with the same thickness as in Example 1, and the negative current collector in this comparative example is a conventional copper foil with the same thickness as in Example 1. The positive electrode sheet in this comparative example is formed by coating the positive electrode paste onto both sides of the aluminum foil, and the negative electrode sheet is formed by coating the negative electrode paste onto both sides of the copper foil. The number of positive and negative electrode sheets is the same as in Example 1.

[0127]

[0128] Test case

[0129] Battery internal resistance test: The batteries of the above examples and comparative examples were subjected to battery internal resistance tests using a HIOKI internal resistance tester (model 3554). The test results are shown in Table 2.

[0130] Battery rate performance test: The batteries of the above embodiments and comparative examples were subjected to rate performance tests, specifically including the following steps: at 25°C, the batteries were discharged at a constant current rate of 1C to 3.0V, then charged at a constant current and constant voltage rate of 1C to 4.20V, and then discharged at a 1C rate to 3.0V, with a discharge capacity C1; then charged at a constant current and constant voltage rate of 1C to 4.20V, and then discharged at a 3C rate to 3.0V, with a discharge capacity C2; the 3C rate discharge capacity retention rate C% = C2 / C1 × 100%. The test results are shown in Table 2. The test results of Embodiment 1 and Comparative Example 1 are as follows. Figure 2 As shown, by Figure 2 It can be seen that, compared to Comparative Example 1 (that is...) Figure 2 Conventional solid-state batteries in the example), Example 1 (i.e. Figure 2 The battery of the present invention significantly improves the rate performance of the battery by using the above-described spraying preparation method.

[0131] Battery cycle performance test: The batteries of the above examples and comparative examples were subjected to rate performance testing, specifically including the following steps: At 25°C, the batteries were discharged at a constant current rate of 1C to 3.0V, then charged at a constant current and constant voltage rate of 1C to 4.20V, and then discharged at a constant current rate of 1C to 3.0V. This charge-discharge cycle was repeated 500 times. The discharge capacity Q1 at the second cycle and the discharge capacity Q500 at the 500th cycle were measured. The batteries were then fully charged, the cells were removed, and the batteries were left to stand at room temperature for 3 hours.

[0132] The cycle capacity retention rate Q of the battery after 500 cycles is calculated using the following formula. The internal resistance of the battery after 500 cycles is tested using a HIOKI internal resistance tester (model 3554).

[0133] Cyclic capacity retention rate Q = Q500 / Q1 × 100%. Test results are shown in Table 2. The test results for Example 1 and Comparative Example 1 are as follows: Figure 3 As shown, by Figure 3 It can be seen that Example 1 (i.e. Figure 3 The battery of the present invention (in this invention) compared to Comparative Example 1 (i.e., Figure 3 By using the above preparation method, the cycle performance of conventional solid-state batteries has been significantly improved.

[0134]

[0135] As shown in the table, compared with the comparative example, the solid-state battery prepared by spraying in the embodiments of the present invention can improve the rate performance and cycle performance of the battery.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solid-state battery, characterized in that, The battery cell includes a positive electrode, a negative electrode, and a solid electrolyte membrane located between the positive electrode and the negative electrode. The positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector, wherein the positive current collector includes aluminum powder; The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector, wherein the negative electrode current collector includes copper powder.

2. The solid-state battery according to claim 1, characterized in that, The positive electrode, solid electrolyte membrane, and negative electrode are integrated and connected in one piece; And / or, the positive electrode current collector is integrally connected to the positive electrode active material layer; And / or, the negative electrode current collector is integrally connected to the negative electrode active material layer; And / or, the peel strength between the positive electrode active material layer and the positive electrode current collector is 20 N / 15 mm ~ 100 N / 15 mm; And / or the peel strength between the negative electrode active material layer and the negative electrode current collector is 10N / 15mm ~ 80N / 15mm.

3. The solid-state battery according to claim 1 or 2, characterized in that, The positive electrode, negative electrode, and solid electrolyte membrane each independently include solid electrolyte materials.

4. The solid-state battery according to claim 3, characterized in that, The average particle size of the solid electrolyte material is 1 μm to 10 μm; And / or, the average particle size of the aluminum powder is 0.5 μm to 50 μm, preferably 0.5 μm to 20 μm; And / or, the average particle size of the copper powder is 1μm to 100μm, preferably 5μm to 50μm.

5. The solid-state battery according to any one of claims 1-4, characterized in that, The positive electrode current collector also includes a positive electrode current collector binder, wherein the mass percentage of the positive electrode current collector in the positive electrode current collector is 0.5 wt% to 5 wt%. And / or, the negative electrode current collector further includes a negative electrode current collector binder, wherein the negative electrode current collector binder accounts for 0.5wt%~5wt% by mass in the positive electrode current collector; And / or, the positive electrode active material layer further includes a positive electrode active material, wherein the positive electrode active material accounts for 70wt%~95wt% of the mass percentage of the positive electrode active material layer, preferably 83wt%~93wt%; And / or, the negative electrode active material layer further includes a negative electrode active material, wherein the negative electrode active material accounts for 70wt%~90wt% of the mass percentage of the negative electrode active material layer, preferably 75wt%~90wt%; And / or, the thickness of the positive current collector is 3μm~25μm; And / or, the thickness of the negative electrode current collector is 2μm~20μm.

6. The solid-state battery according to claim 5, characterized in that, The positive electrode current collector binder includes one or more of polyethylene oxide, polyvinyl alcohol, polyacrylic acid, and styrene-butadiene rubber; And / or, the negative electrode current collector binder includes one or more of polyethylene oxide, polyvinyl alcohol, polyacrylic acid, and styrene-butadiene rubber; And / or, solid electrolyte materials include one or more of oxide solid electrolyte materials, sulfide solid electrolyte materials, halide solid electrolyte materials, and polymer solid electrolyte materials.

7. The solid-state battery according to any one of claims 1-6, characterized in that, At least one surface of the cell in the thickness direction is provided with a foil, the foil including copper foil; And / or, the solid-state battery further includes an electrolyte dispersed in the cell, preferably the electrolyte accounting for 1wt% to 15wt% of the total mass of the cell.

8. A method for preparing a solid-state battery according to any one of claims 1-7, characterized in that, Includes the following steps, Step 1) Preparation of negative electrode current collector: This includes spraying a negative electrode current collector slurry containing copper powder onto the surface of a substrate to obtain a negative electrode current collector; Step 2) Preparation of negative electrode active material layer: This includes spraying negative electrode slurry onto the surface of the negative electrode current collector on the side away from the substrate to obtain a negative electrode active material layer; Step 3) Solid electrolyte membrane preparation: This includes spraying a solid electrolyte slurry onto the surface of the negative electrode active material layer away from the negative electrode current collector to obtain a solid electrolyte membrane; Step 4) Preparation of positive electrode active material layer: This includes spraying positive electrode slurry onto the surface of the solid electrolyte membrane opposite to the negative electrode current collector to obtain a positive electrode active material layer; Step 5) Preparation of the positive current collector: This includes spraying a positive current collector slurry containing aluminum powder onto the surface of the positive active material layer facing away from the solid electrolyte membrane to obtain a positive current collector and prepare a battery cell.

9. The method for preparing a solid-state battery according to claim 8, characterized in that, Includes the following steps: Repeat steps 1) to 5) N times, N≥1; After the Nth positive electrode current collector preparation, the method further includes spraying the solid electrolyte slurry onto the surface of the Nth positive electrode active material layer away from the positive electrode current collector to obtain the (N+1)th solid electrolyte membrane; spraying the negative electrode slurry onto the surface of the (N+1)th solid electrolyte membrane away from the positive electrode active material layer to obtain the (N+1)th negative electrode active material layer; and then spraying the negative electrode current collector slurry including copper powder onto the surface of the (N+1)th negative electrode active material layer away from the negative electrode active material layer to obtain the (N+1)th negative electrode current collector, thus preparing a battery.

10. The method for preparing a solid-state battery according to any one of claims 8-9, characterized in that, The substrate includes copper foil; And / or, in step 4), after spraying the positive electrode slurry onto the surface of the solid electrolyte membrane opposite to the negative electrode current collector, the product after spraying is further dried. And / or, after obtaining the N+1th negative current collector, a cell precursor is obtained, which also includes sequentially encapsulating the cell precursor and injecting electrolyte.

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