Solid-state battery unit, preparation method thereof and solid-state battery

Abstract

In order to solve the problem that lithium ion transmission is affected due to poor interface compatibility among a positive electrode layer, a negative electrode layer and a solid electrolyte layer of an existing solid-state battery, the invention provides a solid-state battery unit which comprises a solid electrolyte layer, a positive electrode material layer and a negative electrode material layer, the positive electrode material layer and the negative electrode material layer are respectively positioned on two sides of the solid electrolyte layer, and the positive electrode material layer and the solid electrolyte layer are mutually permeated at mutually contacted interfaces to form a positive electrode transition region; and the negative electrode material layer and the solid electrolyte layer are mutually permeated at a mutual contact interface so as to form a negative electrode transition region. Meanwhile, the invention also discloses a solid-state battery comprising the solid-state battery unit and a preparation method of the solid-state battery unit. The solid-state battery unit provided by the invention has relatively low internal resistance, so that the solid-state battery unit can be used under a high-rate charge-discharge condition, and the problem of battery heating is reduced.

Description

Technical Field

[0001] This invention belongs to the field of secondary battery technology, specifically relating to a method for preparing a solid-state battery cell and a solid-state battery. Background Technology

[0002] In solid-state batteries, the positive electrode layer, negative electrode layer, and solid electrolyte layer are in a solid state, and no liquid electrolyte is used. In existing solid-state battery fabrication methods, the positive and negative electrode layers and electrolyte layer are mainly prepared as wet slurries. These slurries are then coated and dried to obtain independent positive, electrolyte, and negative electrode layers. These layers are then combined into battery cells through stacking or winding. This process uses a large amount of solvent and is complex. Furthermore, there is poor compatibility at the interface between the positive and negative electrode layers and the solid electrolyte layer, affecting lithium-ion transport and adversely impacting the battery's electrochemical characteristics. To address this issue, some existing technologies use hot pressing to bond the composite structure composed of the positive and negative electrode layers and the solid electrolyte layer; others add a portion of solid electrolyte to the positive and negative electrode layers to improve their affinity with the solid electrolyte layer. However, these methods cannot completely solve the problem of insufficient interface compatibility. Other existing technologies use the method of directly extruding or coating positive electrode slurry and solid electrolyte slurry onto the positive electrode current collector to form a composite electrode. Although this method solves the interface compatibility problem between the positive electrode layer and the solid electrolyte layer to some extent, due to the limitations of process conditions and material strength, the positive electrode layer and solid electrolyte layer prepared by this method cannot maintain their own shape. The slurry needs to be applied to the surface of the support (such as the positive electrode current collector or the negative electrode current collector), and the positive and negative electrodes need to be prepared separately. It is impossible to achieve the integrated preparation of the battery cell. Therefore, the incompatibility problem between the negative electrode layer and the solid electrolyte layer still exists. Summary of the Invention

[0003] To address the problem of poor interfacial compatibility between the positive and negative electrode layers and the solid electrolyte layer in existing solid-state batteries, which affects lithium-ion transport, this invention provides a method for preparing a solid-state battery cell and a solid-state battery.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] On one hand, the present invention provides a solid-state battery cell, including a solid electrolyte layer, a positive electrode material layer and a negative electrode material layer, wherein the positive electrode material layer and the negative electrode material layer are respectively located on both sides of the solid electrolyte layer, and the positive electrode material layer and the solid electrolyte layer interpenetrate at their contact interface to form a positive electrode transition region, and the negative electrode material layer and the solid electrolyte layer interpenetrate at their contact interface to form a negative electrode transition region.

[0006] Optionally, the solid electrolyte layer includes a solid electrolyte and an electrolyte binder, wherein the mass ratio of the solid electrolyte to the electrolyte binder is (20-80):(80-20).

[0007] Optionally, the solid electrolyte includes one or more of the following: perovskite solid electrolyte, garnet solid electrolyte, NASICON solid electrolyte, and LISICON solid electrolyte.

[0008] Optionally, the positive electrode material layer includes a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and a positive electrode additive, wherein the mass ratio of the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and the positive electrode additive is (82.0~98.5):(0.5~3.0):(1.0~5.0):(0.0~10.0).

[0009] Optionally, the positive electrode active material includes one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-rich manganese oxide.

[0010] Optionally, the negative electrode material layer includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and a negative electrode additive, wherein the mass ratio of the negative electrode active material, the negative electrode conductive agent, the negative electrode binder, and the negative electrode additive is (85.0~98.0):(0.5~3.0):(1.5~5.0):(0.0~7.0).

[0011] Optionally, the negative electrode active material includes one or more of the following: artificial graphite, natural graphite, soft carbon, hard carbon, lithium titanate, silicon, silicon-carbon, and silicon-oxygen materials.

[0012] Optionally, the thickness of the solid electrolyte layer is 5–50 μm, the thickness of the positive electrode transition region is 0.1–5.0 μm, the thickness of the positive electrode material layer is 40.0–200 μm, the thickness of the negative electrode transition region is 0.1–5.0 μm, and the thickness of the negative electrode material layer is 45.0–250 μm.

[0013] Optionally, the solid-state battery cell further includes a positive electrode current collector, which is located on the surface of the positive electrode material layer away from the solid electrolyte layer.

[0014] Optionally, the solid-state battery cell further includes a negative electrode current collector, which is located on the surface of the negative electrode material layer away from the solid electrolyte layer.

[0015] Optionally, the solid-state battery cell includes multiple repeating structures stacked sequentially, each repeating structure including the solid electrolyte layer, the positive electrode material layer, and the negative electrode material layer.

[0016] Optionally, the solid electrolyte layer, the positive electrode material layer, and the negative electrode material layer are stacked and then wound to form the solid-state battery cell.

[0017] On the other hand, the present invention provides a solid-state battery, including a package and a solid-state battery cell as described above.

[0018] On the other hand, the present invention provides a method for preparing a solid-state battery cell as described above, comprising the following steps:

[0019] Solid electrolyte sheet, positive electrode material sheet and negative electrode material sheet are provided, and each of the solid electrolyte sheet, positive electrode material sheet and negative electrode material sheet is an independent self-supporting semi-solid structure containing solvent.

[0020] A positive electrode material sheet is coated on one side of a solid electrolyte sheet, and a negative electrode material sheet is coated on the other side of the solid electrolyte sheet. The two sheets are then pressed together to obtain a composite structure.

[0021] The composite structure is dried to remove the solvent, thus obtaining a solid-state battery cell.

[0022] Optionally, the solid electrolyte sheet is extruded from an electrolyte material, which includes a solid electrolyte, an electrolyte binder, and a first solvent. The mass ratio of the solid electrolyte to the electrolyte binder is (20-80):(80-20), and the solid content of the electrolyte material is 40%-60%.

[0023] Optionally, the positive electrode material sheet is extruded from a positive electrode material, which includes a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and a second solvent. The mass ratio of the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and the additive is (82.0–98.5):(0.5–3.0):(1.0–5.0):(0.0–10.0). The solid content of the positive electrode material is 75%–95%, and the viscosity is 4*10. 4 ~3*10 5 mPa / s.

[0024] Optionally, the negative electrode material sheet is extruded from a negative electrode material, which includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, additives, and a third solvent. The mass ratio of the negative electrode active material, the negative electrode conductive agent, the negative electrode binder, and the additives is (85.0–98.0):(0.5–3.0):(1.5–5.0):(0.0–7.0). The solid content of the negative electrode material is 60%–90%, and the viscosity is 4*10.4 ~3*10 5 mPa / s.

[0025] Optionally, the solid electrolyte sheet, the positive electrode material sheet, and the negative electrode material sheet are all continuous strips. The positive electrode material sheet, the solid electrolyte sheet, and the negative electrode material sheet are sequentially overlapped and then rolled together. Alternatively, one of the positive electrode material sheet and the negative electrode material sheet is overlapped with one side surface of the solid electrolyte sheet and rolled together, and then the other of the positive electrode material sheet and the negative electrode material sheet is overlapped with the other side surface of the solid electrolyte sheet and rolled together.

[0026] Optionally, the following operations are also included:

[0027] A positive electrode current collector is coated on the surface of the positive electrode material sheet facing away from the solid electrolyte sheet, and then pressed together to combine the positive electrode material sheet and the positive electrode current collector.

[0028] Optionally, the following operations are also included:

[0029] A negative electrode current collector is covered on the surface of the negative electrode material sheet opposite to the solid electrolyte sheet, and then pressed together to make the negative electrode material sheet and the negative electrode current collector composite.

[0030] According to the solid-state battery cell provided by the present invention, a positive electrode transition region is formed by mutual penetration between the positive electrode material layer and the solid electrolyte layer; a negative electrode transition region is formed by mutual penetration between the negative electrode material layer and the solid electrolyte layer; thereby effectively improving the ion conduction efficiency between the positive electrode material layer and the solid electrolyte layer and between the negative electrode material layer and the solid electrolyte layer, ensuring the conduction speed of lithium ions between the positive electrode material layer and the negative electrode layer, and the prepared solid-state battery cell has a low internal resistance, which is beneficial for its use under high-rate charge and discharge conditions and reduces battery heat generation problems.

[0031] Meanwhile, regarding the structure of this solid-state battery cell, this invention provides a novel preparation method. Unlike the solid sheet state used in the drying and curing process of existing technologies, and unlike the liquid slurry state used in the extrusion or coating process of existing technologies, this invention uses a self-supporting semi-solid structure to composite a solid electrolyte sheet, a positive electrode material sheet, and a negative electrode material sheet. On the one hand, the self-supporting semi-solid structure has good traction and processing characteristics, possesses the mechanical strength required for lamination and pressing, and in particular, has high process adaptability when performing multi-layer combination operations. On the other hand, the self-supporting semi-solid structure is not completely cured. After lamination and pressing, the interfaces of the positive electrode material sheet and the solid electrolyte sheet interpenetrate, and the interfaces of the negative electrode material sheet and the solid electrolyte sheet interpenetrate, thereby forming a good lithium-ion conduction channel from the negative electrode side to the positive electrode side, effectively reducing the impedance of the solid-state battery cell. At the same time, unlike the hot-pressing composite of the positive electrode, solid electrolyte, and negative electrode in existing technologies, the pressing process provided by this invention can be carried out at room temperature, which can effectively avoid the problem of performance degradation of the positive or negative electrode active materials caused by the high temperature generated by hot pressing. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a solid-state battery cell provided in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of a solid-state battery cell provided in another embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the structure of a solid-state battery cell provided in another embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the fabrication process of a solid-state battery cell according to an embodiment of the present invention;

[0036] Figure 5 This is a cross-sectional electron microscope image of the solid-state battery cell obtained in Comparative Example 2 of the present invention at the junction of the positive electrode and the solid electrolyte sheet;

[0037] Figure 6 This is a cross-sectional electron microscope image of the solid-state battery cell obtained in Embodiment 1 of the present invention at the junction of the positive electrode and the solid electrolyte.

[0038] The reference numerals in the accompanying drawings are as follows:

[0039] 1. Positive electrode material layer; 2. Positive electrode transition region; 3. Solid electrolyte layer; 4. Negative electrode transition region; 5. Negative electrode material layer; 6. Positive electrode current collector; 7. Negative electrode current collector; 8. Positive electrode material sheet; 9. Solid electrolyte sheet; 10. Negative electrode material sheet. Detailed Implementation

[0040] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] See Figure 1 As shown, an embodiment of the present invention provides a solid-state battery cell, including a solid electrolyte layer 3, a positive electrode material layer 1, and a negative electrode material layer 5. The positive electrode material layer 1 and the negative electrode material layer 5 are respectively located on both sides of the solid electrolyte layer 3, and the positive electrode material layer 1 and the solid electrolyte layer 3 interpenetrate at their contact interfaces to form a positive electrode transition region 2, and the negative electrode material layer 5 and the solid electrolyte layer 3 interpenetrate at their contact interfaces to form a negative electrode transition region 4.

[0042] A positive electrode transition region 2 is formed by interpenetration between the positive electrode material layer 1 and the solid electrolyte layer 3. The positive electrode transition region 2 contains components of both the positive electrode material layer 1 and the solid electrolyte layer 3. A negative electrode transition region 4 is formed by interpenetration between the negative electrode material layer 5 and the solid electrolyte layer 3. The negative electrode transition region 2 and the negative electrode transition region 4 effectively improve the ion conduction efficiency between the positive electrode material layer 1 and the solid electrolyte layer 3, as well as between the negative electrode material layer 5 and the solid electrolyte layer 3. This ensures the speed of lithium ion conduction between the positive electrode material layer 1 and the negative electrode material layer 5. The resulting solid-state battery cell has low internal resistance, which is beneficial for its use under high-rate charge and discharge conditions and reduces battery heat generation.

[0043] In some embodiments, the solid electrolyte layer 3 includes a solid electrolyte and an electrolyte binder, wherein the mass ratio of the solid electrolyte to the electrolyte binder is (20-80):(80-20).

[0044] The solid electrolyte is the main component of the solid electrolyte layer 3, serving as both an ion conductor and an electron barrier. Simultaneously, due to its high mechanical strength and thermal stability, the solid electrolyte layer 3 can suppress the growth of lithium dendrites on the negative electrode side during battery cycling, thus improving battery safety. The electrolyte binder serves to bond and fix the solid electrolyte. If the content of the solid electrolyte is too low, it will affect the ion conductivity of the solid electrolyte layer 3 and lead to a decrease in mechanical strength. If the content of the solid electrolyte is too high, the proportion of the electrolyte binder will decrease, which is also detrimental to improving the mechanical strength of the solid electrolyte layer 3 and may easily lead to the problem of pulverization of the solid electrolyte layer 3.

[0045] In some embodiments, the solid electrolyte includes one or more of perovskite solid electrolyte, garnet solid electrolyte, NASICON solid electrolyte, and LISICON solid electrolyte.

[0046] Among them, perovskite-type solid electrolytes include A x B y TiO3, A x B y Ta2O6, A x B y Nb2O6, A h M k D n Ti w At least one of O3, wherein x+3y=2, h+2k+5n+4w=6, 0<x<2, 0<y<2 / 3, h, k, n, w are all greater than 0, A is at least one of Li and Na, B is at least one of La, Ce, Pr, Y, Sc, Nd, Sm, Eu, Gd, M is at least one of Sr, Ca, Ba, Ir, Pt, and D is at least one of Nb and Ta.

[0047] Garnet-type solid electrolytes include Li 7+a-b-3c Al c La 3-a X a Zr 2-b Y b O 12 Where 0≤a≤1, 0≤b≤1, 0≤c≤1, X is one or more of La, Ca, Sr, Ba, and K, and Y is one or more of Ta, Nb, W, and Hf.

[0048] NASICON-type solid electrolytes include one or more of LiM2(PO4)3 and its dopants, where M is Ti, Zr, Ge, Sn or Pb, and the doping element used in the dopant is selected from one or more of Mg, Ca, Sr, Ba, Sc, Al, Ga, In, Nb, Ta, and V.

[0049] LISICON type solid electrolytes include Li 14 A(BO4)4, where A is one or more of Zn, Zr, Cr, and Sn, and B is one or more of Ge, Si, S, and P.

[0050] In some embodiments, the electrolyte binder includes PVDF (polyvinylidene fluoride), CMC (carboxymethyl cellulose), SBR (styrene-butadiene rubber), HNBR (hydrogenated nitrile butadiene rubber), NBR (nitrile butadiene rubber), PAA (polyacrylic acid), PEO (polyethylene oxide), PI (polyimide), PVA (polyvinyl alcohol), PU (polyurethane), PVF (polyvinyl formal), PVP (polyvinylpyrrolidone), PES (polyethersulfone), PMMA (polymethyl methacrylate), PAN (polyacrylonitrile), PTFE (polytetrafluoroethylene), PTFE-Na (sodium polytetrafluoroethylene), PAA-Na (sodium polyacrylate), PAA-Li (lithium polyacrylate), PEI (polyetherimide), PES (polyethersulfone), and PPO (polyphenylene oxide). The following are one or more of the following or their modified derivatives: PPOX (polyphenylene oxide), PS (polystyrene), PP (polypropylene), PE (polyethylene), PS-b-PAA (polystyrene-block-polyacrylic acid), PS-b-P4VP (polystyrene-block-poly4-vinylpyridine), PS-b-PMMA (polystyrene-block-polymethyl methacrylate), PS-b-PEO (polystyrene-block-polyethylene oxide), PS-b-PPO (polystyrene-block-polyphenylene oxide), PS-b-P4VP-b-PMMA (polystyrene-block-poly4-vinylpyridine-block-polymethyl methacrylate), PS-b-P4VP-b-PEO (polystyrene-block-poly4-vinylpyridine-block-polyethylene oxide).

[0051] In some embodiments, the positive electrode material layer 1 includes a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and a positive electrode additive, wherein the mass ratio of the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and the positive electrode additive is (82.0–98.5):(0.5–3.0):(1.0–5.0):(0.0–10.0).

[0052] In the positive electrode transition region 2, along the direction from the positive electrode material layer 1 to the solid electrolyte layer 3, the mass concentration of the positive electrode active material gradually decreases, while the mass concentration of the solid electrolyte gradually increases. The positive electrode transition region 2 is formed by the mutual penetration of the positive electrode material layer 1 and the solid electrolyte layer 3. Through the positive electrode transition region 2, the actual conductive area of ​​the lithium-ion battery between the positive electrode material layer 1 and the solid electrolyte layer 3 can be increased, and the ion transport distance can be shortened.

[0053] In some embodiments, the positive electrode active material includes one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-rich manganese oxide.

[0054] In some embodiments, the positive electrode conductive agent includes one or more of conductive carbon black, conductive carbon spheres, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene, conductive polymer, conductive oxide, carbon nanosheets, conductive carbon nanorods, or reduced graphene oxide.

[0055] In some embodiments, the positive electrode binder includes PVDF (polyvinylidene fluoride), CMC (carboxymethyl cellulose), SBR (styrene-butadiene rubber), HNBR (hydrogenated nitrile butadiene rubber), NBR (nitrile butadiene rubber), PAA (polyacrylic acid), PEO (polyethylene oxide), PI (polyimide), PVA (polyvinyl alcohol), PU (polyurethane), PVF (polyvinyl formal), PVP (polyvinylpyrrolidone), PES (polyethersulfone), PMMA (polymethyl methacrylate), PAN (polyacrylonitrile), PTFE (polytetrafluoroethylene), PTFE-Na (sodium polytetrafluoroethylene), PAA-Na (sodium polyacrylate), PAA-Li (lithium polyacrylate), PEI (polyetherimide), PES (polyethersulfone), and PPO (polyphenylene oxide). The following are one or more of the following or their modified derivatives: PPOX (polyphenylene oxide), PS (polystyrene), PP (polypropylene), PE (polyethylene), PS-b-PAA (polystyrene-block-polyacrylic acid), PS-b-P4VP (polystyrene-block-poly4-vinylpyridine), PS-b-PMMA (polystyrene-block-polymethyl methacrylate), PS-b-PEO (polystyrene-block-polyethylene oxide), PS-b-PPO (polystyrene-block-polyphenylene oxide), PS-b-P4VP-b-PMMA (polystyrene-block-poly4-vinylpyridine-block-polymethyl methacrylate), PS-b-P4VP-b-PEO (polystyrene-block-poly4-vinylpyridine-block-polyethylene oxide).

[0056] In some embodiments, the positive electrode additive includes one or more of the following: perovskite solid electrolyte, garnet solid electrolyte, NASICON solid electrolyte, LISICON solid electrolyte, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, lead titanate, lithium tantalate, lithium niobate, and metal-organic framework materials.

[0057] In some embodiments, the negative electrode material layer 5 includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and a negative electrode additive, wherein the mass ratio of the negative electrode active material, the negative electrode conductive agent, the negative electrode binder, and the negative electrode additive is (85.0–98.0):(0.5–3.0):(1.5–5.0):(0.0–7.0).

[0058] In the negative electrode transition region 4, along the direction from the negative electrode material layer 5 to the solid electrolyte layer 3, the mass concentration of the negative electrode active material gradually decreases, while the mass concentration of the solid electrolyte gradually increases. The negative electrode transition region 4 is formed by the mutual penetration of the negative electrode material layer 5 and the solid electrolyte layer 3. Through the negative electrode transition region 4, the actual conductive area of ​​the lithium-ion battery between the negative electrode material layer 5 and the solid electrolyte layer 3 can be increased, and the ion transport distance can be shortened.

[0059] In some embodiments, the negative electrode active material includes one or more of artificial graphite, natural graphite, soft carbon, hard carbon, lithium titanate, silicon, silicon-carbon, and silicon-oxygen materials.

[0060] In some embodiments, the negative electrode conductive agent includes one or more of conductive carbon black, conductive carbon spheres, conductive graphite, conductive carbon fiber, carbon nanotubes, graphene, conductive polymers, conductive oxides, carbon nanosheets, conductive carbon nanorods, or reduced graphene oxide.

[0061] In some embodiments, the negative electrode binder includes PVDF (polyvinylidene fluoride), CMC (carboxymethyl cellulose), SBR (styrene-butadiene rubber), HNBR (hydrogenated nitrile butadiene rubber), NBR (nitrile butadiene rubber), PAA (polyacrylic acid), PEO (polyethylene oxide), PI (polyimide), PVA (polyvinyl alcohol), PU (polyurethane), PVF (polyvinyl formal), PVP (polyvinylpyrrolidone), PES (polyethersulfone), PMMA (polymethyl methacrylate), PAN (polyacrylonitrile), PTFE (polytetrafluoroethylene), PTFE-Na (sodium polytetrafluoroethylene), PAA-Na (sodium polyacrylate), PAA-Li (lithium polyacrylate), PEI (polyetherimide), PES (polyethersulfone), and PPO (polyphenylene oxide). The following are one or more of the following or their modified derivatives: PPOX (polyphenylene oxide), PS (polystyrene), PP (polypropylene), PE (polyethylene), PS-b-PAA (polystyrene-block-polyacrylic acid), PS-b-P4VP (polystyrene-block-poly4-vinylpyridine), PS-b-PMMA (polystyrene-block-polymethyl methacrylate), PS-b-PEO (polystyrene-block-polyethylene oxide), PS-b-PPO (polystyrene-block-polyphenylene oxide), PS-b-P4VP-b-PMMA (polystyrene-block-poly4-vinylpyridine-block-polymethyl methacrylate), PS-b-P4VP-b-PEO (polystyrene-block-poly4-vinylpyridine-block-polyethylene oxide).

[0062] In some embodiments, the negative electrode additive includes one or more of the following: perovskite solid electrolyte, garnet solid electrolyte, NASICON solid electrolyte, LISICON solid electrolyte, aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, lead titanate, lithium tantalate, lithium niobate, and metal-organic framework materials.

[0063] In some embodiments, the thickness of the solid electrolyte layer is 5–50 μm, the thickness of the positive electrode transition region is 0.1–5.0 μm, the thickness of the positive electrode material layer is 40.0–200 μm, the thickness of the negative electrode transition region is 0.1–5.0 μm, and the thickness of the negative electrode material layer is 45.0–250 μm.

[0064] like Figure 2 As shown, in some embodiments, the solid-state battery cell further includes a positive electrode current collector 6, which is located on the surface of the positive electrode material layer 1 away from the solid electrolyte layer 3.

[0065] The positive current collector 6 is used for electrical extraction from the positive electrode material layer 1. The positive current collector 6 is selected from a metallic material that can conduct electrons. Specifically, the positive current collector 6 includes one or more of aluminum, stainless steel, titanium, nickel, and copper. Preferably, the positive current collector 6 is selected from aluminum.

[0066] The positive current collector 6 can be a foil or a mesh.

[0067] In some embodiments, the positive electrode material layer 1 is disposed on both sides of the positive electrode current collector 6.

[0068] In some embodiments, the solid-state battery cell further includes a negative electrode current collector 7, which is located on the surface of the negative electrode material layer 5 away from the solid electrolyte layer 3.

[0069] The negative electrode current collector 7 is used for electrical extraction from the negative electrode material layer 5. The negative electrode current collector 7 is selected from a metallic material that can conduct electrons. Specifically, the negative electrode current collector 7 includes one or more of aluminum, stainless steel, titanium, nickel, and copper. Preferably, the negative electrode current collector 7 is selected from copper.

[0070] The negative electrode current collector 7 can be a foil or a mesh.

[0071] In some embodiments, the negative electrode material layer 5 is provided on both sides of the negative electrode current collector 7.

[0072] In some embodiments, the solid-state battery cell has a stacked structure.

[0073] In some embodiments, the solid-state battery cell includes a plurality of repeating structures stacked sequentially, each of which includes the solid electrolyte layer 3, the positive electrode material layer 1, and the negative electrode material layer 5.

[0074] Specifically, two adjacent repeating structures are connected to each other through a positive current collector 6 or a negative current collector 7, and both sides of the positive current collector 6 are positive electrode material layers 1, and both sides of the negative current collector 7 are negative electrode material layers 5.

[0075] In some embodiments, the solid-state battery cell has a wound structure.

[0076] In some embodiments, the solid electrolyte layer 3, the positive electrode material layer 1, and the negative electrode material layer 5 are stacked and then wound to form the solid-state battery cell.

[0077] Another embodiment of the present invention provides a solid-state battery, including a package and a solid-state battery cell as described above.

[0078] like Figure 4 As shown, another embodiment of the present invention provides a method for fabricating a solid-state battery cell as described above, comprising the following steps:

[0079] Solid electrolyte sheet 9, positive electrode material sheet 8 and negative electrode material sheet 10 are provided, and each of the solid electrolyte sheet 9, positive electrode material sheet 8 and negative electrode material sheet 10 is an independent self-supporting semi-solid structure containing solvent.

[0080] A positive electrode material sheet 8 is covered on one side of the solid electrolyte sheet 9, and a negative electrode material sheet 10 is covered on the other side of the solid electrolyte sheet 9. The sheets are then pressed together to obtain a composite structure.

[0081] The composite structure is dried to remove the solvent, thus obtaining a solid-state battery cell.

[0082] Unlike the solid sheet state used in existing technologies for drying and curing, and unlike the liquid slurry state used in existing technologies for extrusion or coating, this invention uses a self-supporting semi-solid structure for composite bonding of a solid electrolyte sheet 9, a positive electrode material sheet 8, and a negative electrode material sheet 10. On the one hand, the self-supporting semi-solid structure has good traction and processing characteristics, possesses the mechanical strength required for lamination and pressing, and in particular, has high process adaptability when performing multi-layer combination operations. On the other hand, the self-supporting semi-solid structure is not completely cured. After lamination and pressing, the interfaces of the positive electrode material sheet 8 and the solid electrolyte sheet 9 interpenetrate to form a positive electrode transition region 2, and the interfaces of the negative electrode material sheet 10 and the solid electrolyte sheet 9 interpenetrate to form a negative electrode transition region 4. This forms a good lithium-ion conduction channel from the negative electrode side to the positive electrode side, effectively reducing the impedance of the solid-state battery cell. At the same time, unlike the hot-pressing composite of the positive electrode, solid electrolyte, and negative electrode in existing technologies, the pressing process provided by this invention can be carried out at room temperature, which can effectively avoid the problem of performance degradation of the positive or negative electrode active materials caused by the high temperature generated by hot pressing.

[0083] In the description of this invention, the term "self-supporting semi-solid structure" refers to a state in which the solid electrolyte sheet 9, the positive electrode material sheet 8, or the negative electrode material sheet 10 contains some solvent and is not completely solidified. In this state, the solid electrolyte sheet 9, the positive electrode material sheet 8, or the negative electrode material sheet 10 can maintain its own shape and structural stability without additional support. This structure can independently support the active material or solid electrolyte without the need for conventional current collectors (such as aluminum foil or copper foil).

[0084] In some embodiments, the solid electrolyte sheet 9 is extruded from an electrolyte material comprising a solid electrolyte, an electrolyte binder, and a first solvent, wherein the mass ratio of the solid electrolyte to the electrolyte binder is (20–80):(80–20), the solid content of the electrolyte material is 40%–60%, and the viscosity is 4*10. 4 ~3*10 5 mPa / s.

[0085] In a preferred embodiment, the solid content of the electrolyte material is 45% to 55%.

[0086] In some embodiments, the positive electrode material sheet 8 is extruded from a positive electrode material, which includes a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and a second solvent. The mass ratio of the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and the additive is (82.0–98.5):(0.5–3.0):(1.0–5.0):(0.0–10.0). The solid content of the positive electrode material is 75%–95%, and the viscosity is 4*10. 4 ~3*10 5 mPa / s.

[0087] In a preferred embodiment, the solid content of the positive electrode material is 80% to 90%.

[0088] In some embodiments, the negative electrode material sheet 10 is extruded from a negative electrode material, which includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, additives, and a third solvent. The mass ratio of the negative electrode active material, the negative electrode conductive agent, the negative electrode binder, and the additives is (85.0–98.0):(0.5–3.0):(1.5–5.0):(0.0–7.0), and the solid content of the negative electrode material is 60%–90%.

[0089] In a preferred embodiment, the solid content of the negative electrode material is 67% to 80%.

[0090] In this invention, in order to control the solid electrolyte sheet 9, the positive electrode material sheet 8, and the negative electrode material sheet 10 to have a self-supporting semi-solid structure, the morphology of the solid electrolyte sheet 9, the positive electrode material sheet 8, and the negative electrode material sheet 10 can be adjusted by controlling the content of the electrolyte binder, the positive electrode binder, or the negative electrode binder, as well as the solid content and viscosity of the solid electrolyte sheet 9, the positive electrode material sheet 8, and the negative electrode material sheet 10, so that they achieve a self-supporting and incompletely solidified state, thereby meeting the preparation process requirements of this invention.

[0091] In the above embodiments, if the solid content or viscosity of the electrolyte material, the positive electrode material, and the negative electrode material is too low, it will be difficult to form a self-supporting semi-solid structure after extrusion, resulting in the extrusion of the positive electrode current collector 6 or the negative electrode current collector 7 as the carrier, thus making it difficult to simultaneously satisfy the formation of the positive electrode transition region 2 and the negative electrode transition region 4. If the solid content or viscosity of the electrolyte material, the positive electrode material, and the negative electrode material is too high, it will lead to the problem of the material being difficult to extrude or easily pulverizing after extrusion. It will also be detrimental to the penetration effect between different layers at the interface during the subsequent pressing process, affecting the formation of the positive electrode transition region 2 and the negative electrode transition region 4.

[0092] In some embodiments, during the extrusion molding operation, extrusion power is provided by a screw extruder, and an extrusion die is provided at the end of the screw extruder, the shape of which is the same as the cross-section of the material to be extruded.

[0093] In some embodiments, the "pressing" operation is performed using a roller pressing method. By controlling the gap between the pressing rollers, the thickness of the composite structure after pressing is controlled, thereby controlling the thickness of the final solid-state battery cell.

[0094] It should be noted that in this invention, when the pressing operation involves a multi-layer structure, the multi-layer structure can be pressed simultaneously, or the multi-layer structure can be pressed sequentially by a single layer each time, or the multi-layer pressing and single-layer pressing can be performed alternately.

[0095] In some embodiments, the "pressing" operation is room temperature pressing or high temperature pressing.

[0096] In some embodiments, the solid electrolyte sheet 9, the positive electrode material sheet 8, and the negative electrode material sheet 10 are all continuous strips. The positive electrode material sheet 8, the solid electrolyte sheet 9, and the negative electrode material sheet 10 are sequentially overlapped and then rolled together. Alternatively, one of the positive electrode material sheet 8 and the negative electrode material sheet 10 is overlapped with one side surface of the solid electrolyte sheet 9 and rolled together, and then the other of the positive electrode material sheet 8 and the negative electrode material sheet 10 is overlapped with the other side surface of the solid electrolyte sheet 9 and rolled together.

[0097] like Figure 2 As shown, in some embodiments, when the solid-state battery cell includes a positive electrode current collector 6, the preparation method further includes the following operations:

[0098] A positive electrode current collector 6 is covered on the surface of the positive electrode material sheet 8 that is opposite to the solid electrolyte sheet 9, and then pressed together to make the positive electrode material sheet 8 and the positive electrode current collector 6 composite.

[0099] In some embodiments, when the solid-state battery cell includes a negative electrode current collector 7, the preparation method further includes the following operations:

[0100] A negative electrode current collector 7 is covered on the surface of the negative electrode material sheet 10 away from the solid electrolyte sheet 9, and then pressed together to make the negative electrode material sheet 10 and the negative electrode current collector 7 composite.

[0101] In some embodiments, when the solid-state battery cell includes multiple sequentially stacked repeating structures, the individual repeating structures can be prepared by pressing them together first, and then the multiple repeating structures can be stacked and pressed together again to form an integral structure. After drying the integral structure, the solid-state battery cell is obtained. It should be noted that the drying operation should be performed after the integral structure of the solid-state battery cell has been pressed together to avoid the problem that the positive electrode transition region 2 and the negative electrode transition region 4 cannot be formed due to pressing after drying.

[0102] Specifically, in one embodiment, a single positive electrode material sheet 8, a single solid electrolyte sheet 9, and a single negative electrode material sheet 10 are pressed together to form a repeating structure. Then, multiple repeating structures are stacked sequentially, with the arrangement order of the positive electrode material sheet 8, solid electrolyte sheet 9, and negative electrode material sheet 10 of adjacent repeating structures being opposite, such that the positive electrode material sheets 8 of adjacent repeating structures are opposite to each other, or the negative electrode material sheets 10 of adjacent repeating structures are opposite to each other. A positive electrode current collector 6 is placed between two opposite positive electrode material sheets 8, and a negative electrode current collector 7 is placed between two opposite negative electrode material sheets 10. The structures are then pressed together to form an integral structure, and the integral structure is dried to obtain a solid-state battery cell.

[0103] In another embodiment, a solid electrolyte sheet 9, a positive electrode material sheet 8, a positive electrode current collector 6, a positive electrode material sheet 8, a solid electrolyte sheet 9, a negative electrode material sheet 10, a negative electrode current collector 7, and a negative electrode material sheet 10 are pressed together to form a repeating structure. Then, multiple repeating structures are stacked in sequence and pressed together to form an integral structure. After the integral structure is dried, a solid-state battery cell is obtained.

[0104] The present invention will be further illustrated by the following examples.

[0105] Example 1

[0106] This embodiment illustrates the solid-state battery and its preparation method disclosed in this invention, and includes the following steps:

[0107] Solid electrolyte and electrolyte binder are mixed at a mass ratio of 50:50, and a first solvent is added to adjust the solid content to 45% to obtain the electrolyte material. The solid electrolyte is selected from NASICON-type Li. 1.3 Al 0.3 Ti 1.7 (PO4)3(LATP), the electrolyte binder is selected from PVDF; the electrolyte material is added to a screw extruder and extruded to obtain a solid electrolyte sheet with a self-supporting semi-solid structure;

[0108] The positive electrode active material, positive electrode conductive agent, positive electrode binder, and additives are mixed in a mass ratio of 93.9:2.0:1.6:2.5. A second solvent is added to adjust the solid content to 85% to obtain the positive electrode material. The positive electrode active material is selected from lithium nickel cobalt manganese oxide, the positive electrode conductive agent is selected from carbon nanotubes, the positive electrode binder is selected from HNBR, and the additive is selected from LATP. The positive electrode material is fed into a screw extruder and extruded to obtain a self-supporting semi-solid positive electrode material sheet.

[0109] A negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and additives are mixed in a mass ratio of 95.0:1.5:3.0:0.5. A third solvent is added to adjust the solid content to 70% to obtain the negative electrode material. The negative electrode active material is selected from artificial graphite and silicon carbide, the negative electrode conductive agent is selected from carbon black and carbon nanotubes, and the negative electrode binder is selected from PAA and PAN. The material is fed into a screw extruder and extruded to obtain a self-supporting semi-solid structure negative electrode material sheet.

[0110] Solid electrolyte sheet, positive electrode material sheet, positive electrode current collector, positive electrode material sheet, solid electrolyte sheet, negative electrode material sheet, negative electrode current collector, and negative electrode material sheet are pressed together to form a repeating structure. Multiple repeating structures are then stacked in sequence and pressed together to form an integral structure. After drying the integral structure, a solid-state battery cell is obtained.

[0111] Solid-state batteries are obtained by encapsulating solid-state battery cells.

[0112] Example 2

[0113] This embodiment is used to illustrate the solid-state battery and its preparation method disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0114] The solid content of the electrolyte material is 40%, the solid content of the positive electrode material is 80%, and the solid content of the negative electrode material is 67%.

[0115] Example 3

[0116] This embodiment is used to illustrate the solid-state battery and its preparation method disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0117] The solid content of the electrolyte material is 60%, the solid content of the positive electrode material is 90%, and the solid content of the negative electrode material is 80%.

[0118] Example 4

[0119] This embodiment is used to illustrate the solid-state battery and its preparation method disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0120] The solid content of the electrolyte material is 50%, the solid content of the positive electrode material is 84%, and the solid content of the negative electrode material is 69%.

[0121] Example 5

[0122] This embodiment is used to illustrate the solid-state battery and its preparation method disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0123] The positive electrode active material is selected from lithium iron phosphate, and the solid electrolyte is selected from perovskite-type Li. 0.33 La0.56 TiO3(LLTO)

[0124] Example 6

[0125] This embodiment is used to illustrate the solid-state battery and its preparation method disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0126] The positive electrode active material is selected from lithium cobalt oxide, and the solid electrolyte is selected from Li7La3Zr2O. 12 (LLZO).

[0127] Comparative Example 1

[0128] This comparative example is used to illustrate the solid-state battery and its preparation method disclosed in this invention, and includes the following steps:

[0129] Solid electrolyte and electrolyte binder are mixed in a mass ratio of 50:50, and a first solvent is added to adjust the solid content to 15% to obtain an electrolyte slurry. The solid electrolyte is selected from LATP and the electrolyte binder is selected from PVDF.

[0130] The positive electrode active material, positive electrode conductive agent, positive electrode binder, and additives are mixed in a mass ratio of 93.9:2.0:1.6:2.5. A second solvent is added to adjust the solid content to 60% to obtain the positive electrode material. The positive electrode active material is selected from lithium nickel cobalt manganese oxide, the positive electrode conductive agent is selected from carbon nanotubes, the positive electrode binder is selected from HNBR, and the additive is selected from LATP. The positive electrode slurry is coated on both sides of the positive electrode current collector, and then the electrolyte slurry is coated on the surface of the positive electrode slurry. After drying, a composite positive electrode sheet is obtained.

[0131] A negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and additives are mixed in a mass ratio of 95.0:1.5:3.0:0.5. A third solvent is added to adjust the solid content to 45% to obtain the negative electrode material. The negative electrode active material is selected from artificial graphite and silicon carbide, the negative electrode conductive agent is selected from carbon black and carbon nanotubes, and the negative electrode binder is selected from PAA and PAN. The negative electrode slurry is coated on both sides of the negative electrode current collector and dried to obtain the negative electrode sheet.

[0132] Composite positive and negative electrodes are stacked sequentially and then hot-pressed to obtain a solid-state battery cell.

[0133] Solid-state batteries are obtained by encapsulating solid-state battery cells.

[0134] Comparative Example 2

[0135] This comparative example is used to illustrate the solid-state battery and its preparation method disclosed in this invention, and includes the following steps:

[0136] Solid electrolyte and electrolyte binder are mixed in a mass ratio of 50:50, and a first solvent is added to adjust the solid content to 15% to obtain an electrolyte slurry. The solid electrolyte is selected from LATP, and the electrolyte binder is selected from PVDF. The electrolyte slurry is coated on a substrate film, dried, and then demolded to obtain a solid electrolyte sheet.

[0137] The positive electrode active material, positive electrode conductive agent, and positive electrode binder are mixed in a mass ratio of 93.9:2.0:1.6:2.5. A second solvent is added to adjust the solid content to 60% to obtain a positive electrode slurry. The positive electrode active material is selected from lithium nickel cobalt manganese oxide, the positive electrode conductive agent is selected from carbon nanotubes, and the positive electrode binder is selected from HNBR. The positive electrode slurry is coated on both sides of the positive electrode current collector and dried to obtain a positive electrode sheet.

[0138] A negative electrode active material, a negative electrode conductive agent, and a negative electrode binder are mixed in a mass ratio of 95.0:1.5:3.0:0.5. A third solvent is added to adjust the solid content to 45% to obtain a negative electrode slurry. The negative electrode active material is selected from artificial graphite and silicon carbide, the negative electrode conductive agent is selected from carbon black and carbon nanotubes, and the negative electrode binder is selected from PAA and PAN. The negative electrode slurry is coated on both sides of the negative electrode current collector and dried to obtain a negative electrode sheet.

[0139] A solid-state battery cell is obtained by sequentially stacking a positive electrode, a solid electrolyte sheet, and a negative electrode, and then hot-pressing them.

[0140] Solid-state batteries are obtained by encapsulating solid-state battery cells.

[0141] Performance testing

[0142] I. Cross-sectional electron microscopy observations were performed on the solid-state battery cells prepared in Example 1 and Comparative Example 2. The cross-section of the solid-state battery cell obtained in Comparative Example 2 at the interface between the positive electrode and the solid electrolyte sheet is shown below. Figure 5 As shown, there is a mechanical separation between the positive electrode and the solid electrolyte sheet; the cross-section of the solid-state battery cell obtained in Example 1 at the junction of the positive electrode and the solid electrolyte sheet is shown in Figure 1. Figure 6 As shown, the positive electrode and the solid electrolyte are tightly bonded together with no obvious boundary.

[0143] II. The solid-state batteries prepared above were subjected to the following performance tests:

[0144] DC internal resistance (DCIR): At 25℃, the battery is adjusted to 50% SOC with a current of 1 / 3C rate, left to rest for 60 minutes, and the ending voltage V1 is recorded. The battery is then discharged with a current of 3C rate for 30 seconds, and the ending voltage V2 is recorded. The DCIR value is calculated as (V1-V2)÷3C×1000. The DCIR value is used to characterize the battery impedance.

[0145] Discharge ratio: At 25℃, the battery is fully charged with a current at a 1 / 3C rate, and then discharged completely with a current at a 1 / 3C rate. The capacity discharged is denoted as C. 1 / 3C The battery is then fully charged using a current at 1 / 3C rate, and then discharged completely using a current at 2C rate. The discharged capacity is denoted as C. 2C , using C 2C ÷C 1 / 3C The value represents the magnitude of the 2C discharge ratio;

[0146] Capacity retention: At 25°C, the battery is fully charged at a 1 / 3C rate and then discharged at a 1 / 3C rate. This is recorded as one cycle, and the initial capacity is recorded as C0. This charging and discharging cycle is repeated 500 times, and the capacity of the 500th cycle is recorded as C0. 500 , using C 500 The value of ÷C0 represents the capacity retention rate after 500 cycles.

[0147] The test results are entered into Table 1.

[0148] Table 1

[0149] sample DCIR(mΩ) 2C discharge ratio (%) Capacity retention rate after 500 cycles (%) Example 1 82 95.4 91.6 Example 2 84 95.0 89.7 Example 3 93 94.5 88.5 Example 4 90 94.7 89.1 Example 5 104 95.2 94.0 Example 6 85 95.3 85.2 Comparative Example 1 254 78.3 69.5 Comparative Example 2 300 66.5 58.7

[0150] As can be seen from the test results in Table 1, the solid-state batteries prepared using the scheme of the present invention in Examples 1 to 6 have lower DCIR impedance and higher discharge rate, as well as higher cycle capacity retention.

[0151] Comparing the test results of Example 1 and Comparative Examples 1 and 2, it can be seen that the technical solution of the present invention can effectively improve the problem of poor interface compatibility between the positive and negative electrode layers and the solid electrolyte layer in solid-state batteries, which affects lithium-ion transport. The prepared battery has better electrochemical performance.

[0152] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solid-state battery cell, characterized in that, It includes a solid electrolyte layer, a positive electrode material layer, and a negative electrode material layer. The positive electrode material layer and the negative electrode material layer are located on both sides of the solid electrolyte layer, and the positive electrode material layer and the solid electrolyte layer interpenetrate at their contact interface to form a positive electrode transition region. The negative electrode material layer and the solid electrolyte layer interpenetrate at their contact interface to form a negative electrode transition region.

2. The solid-state battery cell according to claim 1, characterized in that, The solid electrolyte layer comprises a solid electrolyte and an electrolyte binder, wherein the mass ratio of the solid electrolyte to the electrolyte binder is (20-80):(80-20).

3. The solid-state battery cell according to claim 2, characterized in that, The solid electrolyte includes one or more of the following: perovskite solid electrolyte, garnet solid electrolyte, NASICON solid electrolyte, and LISICON solid electrolyte.

4. The solid-state battery cell according to claim 1, characterized in that, The positive electrode material layer includes a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and a positive electrode additive. The mass ratio of the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and the positive electrode additive is (82.0~98.5):(0.5~3.0):(1.0~5.0):(0.0~10.0).

5. The solid-state battery cell according to claim 4, characterized in that, The positive electrode active material includes one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium-rich manganese oxide.

6. The solid-state battery cell according to claim 1, characterized in that, The negative electrode material layer includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and a negative electrode additive. The mass ratio of the negative electrode active material, the negative electrode conductive agent, the negative electrode binder, and the negative electrode additive is (85.0~98.0):(0.5~3.0):(1.5~5.0):(0.0~7.0).

7. The solid-state battery cell according to claim 6, characterized in that, The negative electrode active material includes one or more of the following: artificial graphite, natural graphite, soft carbon, hard carbon, lithium titanate, silicon, silicon-carbon, and silicon-oxygen materials.

8. The solid-state battery cell according to claim 1, characterized in that, The thickness of the solid electrolyte layer is 5–50 μm, the thickness of the positive electrode transition region is 0.1–5.0 μm, the thickness of the positive electrode material layer is 40.0–200 μm, the thickness of the negative electrode transition region is 0.1–5.0 μm, and the thickness of the negative electrode material layer is 45.0–250 μm.

9. The solid-state battery cell according to claim 1, characterized in that, The solid-state battery cell also includes a positive electrode current collector, which is located on the surface of the positive electrode material layer away from the solid electrolyte layer.

10. The solid-state battery cell according to claim 1, characterized in that, The solid-state battery cell also includes a negative electrode current collector, which is located on the surface of the negative electrode material layer away from the solid electrolyte layer.

11. The solid-state battery cell according to claim 1, characterized in that, The solid-state battery cell includes multiple repeating structures stacked sequentially, each of which includes the solid electrolyte layer, the positive electrode material layer, and the negative electrode material layer.

12. The solid-state battery cell according to claim 1, characterized in that, The solid electrolyte layer, positive electrode material layer, and negative electrode material layer are stacked and then wound to form the solid-state battery cell.

13. A solid-state battery, characterized in that, It includes a package and a solid-state battery cell as described in any one of claims 1 to 12.

14. The method for preparing a solid-state battery cell according to any one of claims 1 to 12, characterized in that, The following steps are included: Solid electrolyte sheet, positive electrode material sheet and negative electrode material sheet are provided, and each of the solid electrolyte sheet, positive electrode material sheet and negative electrode material sheet is an independent self-supporting semi-solid structure containing solvent. A positive electrode material sheet is coated on one side of a solid electrolyte sheet, and a negative electrode material sheet is coated on the other side of the solid electrolyte sheet. The two sheets are then pressed together to obtain a composite structure. The composite structure is dried to remove the solvent, thus obtaining a solid-state battery cell.

15. The method for preparing a solid-state battery cell according to claim 14, characterized in that, Solid electrolyte sheets are extruded from electrolyte material, which includes a solid electrolyte, an electrolyte binder, and a first solvent. The mass ratio of the solid electrolyte to the electrolyte binder is (20-80):(80-20). The solid content of the electrolyte material is 40%-60%, and the viscosity is 4*10. 4 ~3*10 5 mPa / s.

16. The method for preparing a solid-state battery cell according to claim 14, characterized in that, The positive electrode material sheet is extruded from a positive electrode material, which includes a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, a positive electrode additive, and a second solvent. The mass ratio of the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and the positive electrode additive is (82.0–98.5):(0.5–3.0):(1.0–5.0):(0.0–10.0). The solid content of the positive electrode material is 75%–95%, and the viscosity is 4*10. 4 ~3*10 5 mPa / s.

17. The method for preparing a solid-state battery cell according to claim 14, characterized in that, The negative electrode material sheet is extruded from a negative electrode material, which includes a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, a negative electrode additive, and a third solvent. The mass ratio of the negative electrode active material, the negative electrode conductive agent, the negative electrode binder, and the negative electrode additive is (85.0–98.0):(0.5–3.0):(1.5–5.0):(0.0–7.0). The solid content of the negative electrode material is 60%–90%.

18. The method for preparing a solid-state battery cell according to claim 14, characterized in that, The solid electrolyte sheet, the positive electrode material sheet, and the negative electrode material sheet are all continuous strips. The positive electrode material sheet, the solid electrolyte sheet, and the negative electrode material sheet are overlapped in sequence and then rolled together. Alternatively, one of the positive electrode material sheet and the negative electrode material sheet is overlapped with one side surface of the solid electrolyte sheet and rolled together, and then the other of the positive electrode material sheet and the negative electrode material sheet is overlapped with the other side surface of the solid electrolyte sheet and rolled together.

19. The method for preparing a solid-state battery cell according to claim 14, characterized in that, This also includes the following operations: A positive electrode current collector is coated on the surface of the positive electrode material sheet facing away from the solid electrolyte sheet, and then pressed together to combine the positive electrode material sheet and the positive electrode current collector.

20. The method for preparing a solid-state battery cell according to claim 14, characterized in that, This also includes the following operations: A negative electrode current collector is covered on the surface of the negative electrode material sheet opposite to the solid electrolyte sheet, and then pressed together to make the negative electrode material sheet and the negative electrode current collector composite.

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