Solid-state battery cell, method of manufacturing a solid-state battery cell, and solid-state battery

Abstract

The application relates to the technical field of solid-state batteries, and discloses a solid-state battery cell, a preparation method thereof and a solid-state battery. The solid-state battery cell comprises: positive and negative electrode sheets stacked together and a solid-state electrolyte film between the two; the negative electrode sheet is arranged to protrude beyond the positive electrode sheet on at least one side in the circumferential direction to form an overhang region; and a pressure-sensitive adhesive encapsulation layer is arranged in the overhang region corresponding to a gap region. The pressure-sensitive adhesive material has certain ductility and viscosity. Therefore, when the electrode material of the solid-state battery changes in volume due to forming pressure or in the process of charging and discharging, the pressure-sensitive adhesive can adapt to the volume change of the electrode material, and the interface between the pressure-sensitive adhesive encapsulation layer and the electrode material / electrode sheet cannot be separated, so that the contact between the positive and negative electrode sheets can be effectively avoided, the battery short circuit can be effectively prevented, the yield of the cell can be improved, and the cycle performance of the battery can be improved.

Description

Technical Field

[0001] The present application relates to the field of solid-state battery technology, for example, to a solid-state battery cell and a preparation method thereof, and a solid-state battery. Background Art

[0002] Negative electrode overhang refers to the portion of the negative electrode sheet that exceeds the positive electrode sheet in the length and / or width direction. This design is mainly to prevent lithium ions from precipitating on the surface of the negative electrode to form lithium dendrites during charging, thereby piercing the diaphragm and causing a short circuit in the battery, triggering thermal runaway, and improving the safety of the battery. However, since all-solid-state batteries usually require a higher assembly pressure during the preparation process. When using traditional plates with a large negative electrode and a small positive electrode, when pressurizing and assembling solid-state batteries, due to the different sizes of the positive and negative electrode plates and uneven force, it is easy to cause the negative electrode overhang area to collapse, and the positive and negative electrodes to contact, resulting in a battery short circuit.

[0003] At present, in order to solve the problem that the negative electrode overhang area is prone to collapse during the solid-state battery assembly process, resulting in contact between the positive and negative electrodes and then causing a battery short circuit, most methods adopt the method of filling materials in the gaps corresponding to the negative electrode overhang area for support to avoid the collapse of the negative electrode overhang area during the solid-state battery assembly process. Although the collapse problem of the negative electrode overhang area is solved, the volume change inside the battery during charging and discharging causes the contact between the filling area and the battery interface to fail, resulting in poor battery cycle performance.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0005] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0006] The embodiments of the present disclosure provide a solid-state battery cell, a preparation method thereof, and a solid-state battery to solve the problem of interface contact failure caused by molding pressure or volume change of electrode materials at the bonding interface between the solid-state battery cell packaging layer and the electric chip layer.

[0007] In some embodiments, the solid-state battery cell includes: alternatingly stacked positive electrode sheets and negative electrode sheets, and a solid electrolyte membrane is arranged between adjacent positive electrode sheets and negative electrode sheets; at least one side of the negative electrode sheet extends beyond the positive electrode sheet to form an overhang area; wherein a pressure-sensitive adhesive packaging layer is arranged in the gap area corresponding to the overhang area; the pressure-sensitive adhesive of the pressure-sensitive adhesive packaging layer includes a solvent-based pressure-sensitive adhesive.

[0008] In some embodiments, the method for preparing a solid-state battery cell comprises: preparing a positive electrode sheet, a negative electrode sheet and a solid electrolyte membrane; alternately stacking the positive electrode sheets and the negative electrode sheets, and setting a solid electrolyte membrane between adjacent positive electrode sheets and negative electrode sheets to obtain a cell; wherein the positive electrode sheet comprises a positive electrode composite sheet having a pressure-sensitive adhesive encapsulation layer provided in its hollow foil area; or, the negative electrode sheet comprises a negative electrode composite sheet having a pressure-sensitive adhesive encapsulation layer provided on its overhang area surface; or, the negative electrode sheet comprises a negative electrode combination sheet having a solid electrolyte membrane transferred thereon and a pressure-sensitive adhesive encapsulation layer provided on the surface of the solid electrolyte membrane corresponding to the overhang area; a pressure-sensitive adhesive encapsulation layer is provided in the void area corresponding to the overhang area; the pressure-sensitive adhesive of the pressure-sensitive adhesive encapsulation layer comprises a solvent-based pressure-sensitive adhesive.

[0009] An embodiment of the present disclosure provides a solid-state battery, comprising the aforementioned solid-state battery cell, or a cell prepared by the aforementioned method for preparing the solid-state battery cell.

[0010] The solid-state battery cell, preparation method thereof, and solid-state battery provided by the embodiments of the present disclosure can achieve the following technical effects:

[0011] In the solid-state battery cell of the embodiment of the present disclosure, a pressure-sensitive adhesive packaging layer is provided in the gap area corresponding to the overhang area. Compared with the existing hot-melt adhesive packaging layer or the inorganic material packaging layer mainly composed of solid electrolyte materials, the pressure-sensitive adhesive packaging layer uses pressure-sensitive adhesive material as the packaging layer material. The pressure-sensitive adhesive material has certain ductility and viscosity. Therefore, when the electrode material of the solid-state battery undergoes volume changes due to molding pressure or during the charge and discharge cycle, the pressure-sensitive adhesive utilizes its viscosity and ductility to adapt to the volume change of the electrode material, that is, the pressure-sensitive adhesive packaging layer can follow the volume change of the electrode material, and there will be no interface separation between the pressure-sensitive adhesive packaging layer and the electrode material / electrode piece, thereby effectively avoiding contact failure between the positive and negative electrode pieces and the electrolyte membrane, thereby improving the cycle performance of the battery.

[0012] Also, during the preparation of the battery cell, the pressure-sensitive adhesive packaging layer can fix the electrode plate layer and the solid electrolyte membrane to prevent the active material and electrolyte in the middle from expanding or shifting; on the other hand, the pressure-sensitive adhesive packaging layer has a certain viscosity, and when the battery cell is pressurized and formed, the positive and negative electrodes are bonded to each other through the pressure-sensitive adhesive material. Using pressure-sensitive adhesive material as the packaging material for the overhang area of ​​the solid-state battery can not only fix the positive and negative electrodes, prevent the electrodes from deforming under high pressure, thereby causing contact between the positive and negative edges, but also prevent the positive and negative electrodes from being misaligned, avoid short circuits during the battery preparation process, greatly improve the yield rate in the production process of solid-state lithium-ion batteries, and inhibit the expansion of various components of the solid-state lithium-ion battery electrodes during the charging and discharging process, thereby effectively improving the battery's cycle energy. The battery cell packaging method of the disclosed embodiment is simple and practical.

[0013] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] One or more embodiments are exemplarily described by corresponding drawings. These exemplary descriptions and drawings do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation. In addition,

[0015] Figure 1 is a structural schematic diagram of a solid-state battery cell provided by an embodiment of the present disclosure;

[0016] Figure 2 is a schematic structural diagram of another solid-state battery cell provided by an embodiment of the present disclosure;

[0017] Figure 3 is a schematic structural diagram of another solid-state battery cell provided by an embodiment of the present disclosure;

[0018] Figure 4 is a schematic structural diagram of another solid-state battery cell provided by an embodiment of the present disclosure;

[0019] Figure 5 This is a flowchart of a method for preparing a solid-state battery cell provided by an embodiment of the present disclosure;

[0020] Figure 6 This is a flowchart of a method for preparing a solid-state battery cell provided in an embodiment of the present disclosure.

[0021] Reference numerals:

[0022] 100. Lamination unit; 10. Positive electrode sheet; 11. Positive electrode current collector layer; 12. Positive electrode active material layer; 20. Negative electrode sheet; 200. Overhang area; 21. Negative electrode active material layer; 22. Negative electrode current collector layer; 30. Solid electrolyte membrane; 40. Pressure-sensitive adhesive packaging layer; 41. Pressure-sensitive adhesive packaging inner layer; 42. Pressure-sensitive adhesive packaging outer layer. DETAILED DESCRIPTION

[0023] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The accompanying drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0024] In the description and claims of the embodiments of the present disclosure, as well as in the accompanying drawings, the terms "first," "second," and the like are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate to facilitate understanding of the embodiments of the present disclosure described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0025] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to having a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0026] Furthermore, the terms "disposed," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a removable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or an internal connection between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this disclosure based on the specific circumstances.

[0027] Unless otherwise stated, the term "plurality" means two or more.

[0028] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0029] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0031] Combine Figures 1 to 4 As shown, an embodiment of the present disclosure provides a cell structure of a solid-state battery, comprising alternatingly stacked positive electrode sheets 10 and negative electrode sheets 20, and a solid electrolyte membrane 30 is arranged between adjacent positive electrode sheets 10 and negative electrode sheets 20; the negative electrode sheet 20 extends beyond the positive electrode sheet 10 on at least one side in a circumferential direction to form an overhang area 200; wherein, a pressure-sensitive adhesive packaging layer 40 is arranged in the gap area corresponding to the overhang area 200; the pressure-sensitive adhesive of the pressure-sensitive adhesive packaging layer includes a solvent-based pressure-sensitive adhesive.

[0032] In the solid-state battery cell of the embodiment of the present disclosure, a pressure-sensitive adhesive packaging layer 40 is provided in the gap area corresponding to the overhang area 200. Compared with the existing hot-melt adhesive packaging layer or the inorganic material packaging layer mainly composed of solid electrolyte materials, the pressure-sensitive adhesive packaging layer 40 uses pressure-sensitive adhesive material as the packaging layer material. The pressure-sensitive adhesive material has certain ductility and viscosity. Therefore, when the electrode material of the solid-state battery undergoes volume changes due to molding pressure or during the charge and discharge cycle, the pressure-sensitive adhesive utilizes its viscosity and ductility to adapt to the volume change of the electrode material, that is, the pressure-sensitive adhesive packaging layer can follow the volume change of the electrode material, and there will be no interface separation between the pressure-sensitive adhesive packaging layer and the electrode material / electrode piece, thereby effectively avoiding contact failure between the positive and negative electrode pieces and the electrolyte membrane, thereby improving the cycle performance of the battery.

[0033] Furthermore, the pressure-sensitive adhesive packaging layer 40 can fix the electrode plate layer and the solid electrolyte membrane, preventing the active material and electrolyte in the middle from expanding or shifting. On the other hand, the pressure-sensitive adhesive packaging layer 40 has a certain viscosity, and when the solid-state battery cell is pressurized and formed, the positive and negative electrode plates are bonded together by the pressure-sensitive adhesive material. Using pressure-sensitive adhesive material as the packaging material for the overhang area of ​​the solid-state battery can not only fix the positive and negative electrode plates, preventing the plates from deforming under high pressure, thereby causing the positive and negative electrode edges to contact, but also prevent the positive and negative electrode plates from being misaligned, avoiding short circuits during the battery preparation process, greatly improving the yield rate in the production process of solid-state lithium-ion batteries, and suppressing the expansion of various components of the solid-state lithium-ion battery plates during the charge and discharge process, thereby effectively improving the battery's cycle energy.

[0034] It can be understood that the gap area corresponding to the overhang area 200 refers to a space area on the periphery of the positive electrode sheet 10 corresponding to the overhang area 200 of the negative electrode sheet 20. Generally, a positive electrode sheet 10, a solid electrolyte membrane 30 (defined as a first solid electrolyte membrane), a negative electrode sheet 20 and a solid electrolyte membrane 30 (defined as a second solid electrolyte membrane) stacked in sequence form a stacking unit 100 (such as Figure 2 As shown in FIG), the battery core structure generally includes a plurality of laminated units 100 (as shown in FIG). Figure 3 As shown, the solid electrolyte membrane (i.e., the second solid electrolyte membrane) on the outside of one laminate unit 100 is in contact and stacked with the positive electrode sheet 10 on the outside of an adjacent laminate unit 100, forming a battery cell structure. Therefore, the gap corresponding to the overhang region 200 is the space between the overhang regions 200 of the two negative electrode sheets 20 of adjacent laminate units 100.

[0035] In the solid-state battery cell of the disclosed embodiment, the pressure-sensitive adhesive encapsulation layer 40 is disposed within the interstitial region corresponding to the overhang region 200 . This means that the pressure-sensitive adhesive encapsulation layer 40 is in contact with the interface of the interstitial region. For example, the pressure-sensitive adhesive encapsulation layer 40 is in contact with the end face of the positive electrode tab and the surface of the negative electrode tab 20 (solid electrolyte membrane 30) corresponding to the overhang region 200 . In other words, the pressure-sensitive adhesive encapsulation layer 40 completely fills the interstitial region.

[0036] In the embodiment of the present disclosure, the pressure-sensitive adhesive encapsulation layer 40 adopts a solvent-based pressure-sensitive adhesive, which not only has excellent ductility and viscosity, but also has good wettability, fast drying, strong initial adhesion, water resistance, good temperature resistance, resistance to corrosion by various chemical substances, such as acids, alkalis, solvents, etc., and can also resist corrosion by moisture, etc., and has a low heating and curing temperature, low cost, low energy consumption, and is adaptable to the internal environment of fixed batteries.

[0037] Optionally, the pressure-sensitive adhesive material includes an acrylic solvent-based pressure-sensitive adhesive.

[0038] In some embodiments, the solvent-based pressure-sensitive adhesive includes an acrylate-based pressure-sensitive adhesive.

[0039] In some embodiments, the pressure-sensitive adhesive encapsulation layer 40 is obtained by in-situ polymerization of an acrylate-type pressure-sensitive adhesive encapsulation slurry disposed in the void area corresponding to the overhang area; wherein the acrylate-type pressure-sensitive adhesive encapsulation slurry includes an acrylate monomer, an initiator, and a solvent, and the acrylate monomer includes a hard monomer and a soft monomer. In this embodiment, the pressure-sensitive adhesive encapsulation layer is obtained by in-situ polymerization after being disposed in the void area corresponding to the overhang area in the form of a slurry. The slurry has certain flow properties, is easy to spread, and the thickness of the spread layer is easy to control, which facilitates the arrangement of the pressure-sensitive adhesive encapsulation layer. wherein, in the acrylate-type pressure-sensitive adhesive encapsulation slurry, at the polymerization temperature, the initiator decomposes, triggering a polymerization reaction between the hard monomer and the soft monomer, thereby forming a pressure-sensitive adhesive.

[0040] The polymerization temperature of the acrylic pressure-sensitive adhesive encapsulation paste is determined by the decomposition temperature of the initiator. For example, when the initiator is azobisisobutyronitrile, the polymerization temperature is 60°C to 70°C, specifically 65°C. For example, when the initiator is benzoyl peroxide, the polymerization temperature is 80°C to 100°C.

[0041] Optionally, the acrylate pressure-sensitive adhesive encapsulation slurry comprises, by weight, 35% to 60% acrylate monomer, 0.1% to 5% initiator, and 35% to 60% solvent, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5. By adjusting the amount of solvent, the fluidity of the slurry is adjusted to facilitate placement (e.g., coating, 3D printing, or screen printing) in the gap area corresponding to the overhang area.

[0042] Optionally, based on mass percentage, the acrylate pressure-sensitive adhesive encapsulation slurry includes 43% to 55% of acrylate monomer, 0.1% to 2% of initiator and 43% to 55% of solvent, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5.

[0043] Optionally, based on mass percentage, the acrylate pressure-sensitive adhesive encapsulation slurry includes 48% to 52% of acrylate monomer, 0.1% to 1% of initiator and 48% to 52% of solvent, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5.

[0044] Optionally, based on mass percentage, the acrylic pressure-sensitive adhesive encapsulation slurry includes 50% of acrylic acid ester monomer, 0.1% to 1% of initiator and 49% to 49.9% of solvent, wherein the acrylic acid ester monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5.

[0045] In acrylic ester pressure-sensitive adhesive encapsulation slurries, the mass ratio of hard monomer to soft monomer can be adjusted to produce pressure-sensitive adhesives with varying viscosities. It's understood that a higher amount of hard monomer results in a lower viscosity, while a higher amount of soft monomer results in a higher viscosity. The mass ratio of hard monomer to soft monomer is determined based on the type of hard monomer and soft monomer, as well as the desired viscosity of the pressure-sensitive adhesive.

[0046] Optionally, in the acrylate pressure-sensitive adhesive encapsulation slurry, the mass ratio of the hard monomer to the soft monomer is 0.25 to 5. Optionally, the mass ratio of the hard monomer to the soft monomer is 0.5 to 5. Optionally, the mass ratio of the hard monomer to the soft monomer is 1 to 5. Optionally, the mass ratio of the hard monomer to the soft monomer is 2 to 5. Optionally, the mass ratio of the hard monomer to the soft monomer is 3 to 5.

[0047] In the embodiment of the present disclosure, the mass ratio of the hard monomer to the soft monomer is 0.2-5, which can be understood as (0.2-5) : 1. Other mass ratios can be understood by analogy and are not described here one by one.

[0048] Optionally, the hard monomer comprises methyl acrylate and / or methyl methacrylate;

[0049] Optionally, the soft monomer includes one or more of ethyl acrylate, n-butyl acrylate, and n-butyl methacrylate.

[0050] Optionally, the initiator comprises azobisisobutyronitrile and / or benzoyl peroxide.

[0051] Optionally, the solvent includes one or more of N-methylpyrrolidone, isopropyl alcohol, toluene and xylene.

[0052] Optionally, the hard monomer includes methyl acrylate, the soft monomer includes ethyl acrylate, and the mass ratio of methyl acrylate to ethyl acrylate is 3 to 5. Optionally, the mass ratio of methyl acrylate to ethyl acrylate is 4.

[0053] In some embodiments, combined Figure 4As shown, the pressure-sensitive adhesive packaging layer 40 has a viscosity that decreases from the inside to the outside. In this embodiment, the smaller the viscosity of the pressure-sensitive adhesive packaging layer, the better its supporting performance. In this way, the pressure-sensitive adhesive packaging layer with a large viscosity on the inside increases the interface contact area with the electric chip layer and thus increases the bonding strength. The pressure-sensitive adhesive packaging layer with a small viscosity on the outside is equivalent to providing an outer support ring for the overhang gap area, thereby improving the supporting performance of the pressure-sensitive adhesive packaging layer. In this embodiment, the viscosity change is achieved by adjusting the mass ratio of the hard monomer to the soft monomer. It can be understood that the inside refers to the side close to the positive electrode plate 10, and the outside refers to the side away from the positive electrode plate 10.

[0054] In this embodiment, the obtained product can be obtained by gradually placing a plurality of acrylate pressure-sensitive adhesive encapsulation pastes with increasing mass ratios of hard monomers to soft monomers in the overhang gap area from the inside to the outside.

[0055] Optionally, the pressure-sensitive adhesive encapsulation layer 40 includes an inner pressure-sensitive adhesive encapsulation layer 41 and an outer pressure-sensitive adhesive encapsulation layer 42, wherein the viscosity of the inner pressure-sensitive adhesive encapsulation layer 41 is greater than the viscosity of the outer pressure-sensitive adhesive encapsulation layer 42. In this embodiment, the inner pressure-sensitive adhesive encapsulation layer 41 is obtained by in-situ polymerization of a first acrylate-type pressure-sensitive adhesive encapsulation slurry, wherein the mass ratio of hard monomer to soft monomer in the first acrylate-type pressure-sensitive adhesive encapsulation slurry is 0.5 to 2; the outer pressure-sensitive adhesive encapsulation layer 42 is obtained by in-situ polymerization of a second acrylate-type pressure-sensitive adhesive encapsulation slurry, wherein the mass ratio of hard monomer to soft monomer in the second acrylate-type pressure-sensitive adhesive encapsulation slurry is 2 to 5.

[0056] In some embodiments, the positive electrode plate 10 is a positive electrode composite plate having a pressure-sensitive adhesive encapsulation layer disposed in the hollow foil region thereof. In this embodiment, the pressure-sensitive adhesive encapsulation layer is pre-disposed in the hollow foil region of the positive electrode plate. The hollow foil region is the current collector region outside the positive electrode material region of the positive electrode plate 10, which is located in the void region. This allows the pressure-sensitive adhesive encapsulation layer 40 to be formed in the void region corresponding to the overhang region after the positive electrode composite plate, solid electrolyte membrane, and negative electrode plate are stacked and heated and cured.

[0057] In some embodiments, the negative electrode plate 20 is a negative electrode composite plate having a pressure-sensitive adhesive encapsulation layer disposed on the surface of the overhang area. In this embodiment, the pressure-sensitive adhesive encapsulation layer is pre-disposed on the surface of the overhang area of ​​the negative electrode plate, and the surface of the overhang area corresponds to the void area. This allows the positive electrode plate, solid electrolyte membrane, and negative electrode composite plate to be stacked and then heated and cured to form the pressure-sensitive adhesive encapsulation layer 40 in the void area corresponding to the overhang area.

[0058] In some embodiments, the negative electrode plate is a negative electrode combination plate having a solid electrolyte membrane transferred thereon, and a pressure-sensitive adhesive encapsulation layer disposed on the surface of the solid electrolyte membrane corresponding to the overhang region. In this embodiment, the pressure-sensitive adhesive encapsulation layer 40 is pre-disposed on the surface of the solid electrolyte membrane 30 corresponding to the overhang region 200 of the negative electrode plate 20 to which the solid electrolyte membrane 30 has been transferred. This ensures that after the positive electrode plate 10 and the negative electrode combination plate are stacked, the pressure-sensitive adhesive encapsulation layer 40 is formed in the gap corresponding to the overhang region 200.

[0059] In the embodiment of the present disclosure, the acrylate pressure-sensitive adhesive encapsulation slurry can be provided by conventional means such as coating and pouring, without limitation.

[0060] Optionally, the acrylic pressure-sensitive adhesive encapsulation slurry is disposed in the gap area corresponding to the overhang area 200 by 3D printing or screen printing.

[0061] Optionally, an acrylic pressure-sensitive adhesive encapsulation slurry is printed into the gap area corresponding to the overhang area using a 3D printing method. In this embodiment, the use of a 3D printing method to set the pressure-sensitive adhesive encapsulation slurry allows for precise control of the size of the printing area and the amount of printing. This ensures that the pressure-sensitive adhesive encapsulation material fully fills the gap area while also ensuring sufficient contact and bonding with the electrode material of the electrode plate, thereby improving the performance of the solid-state battery.

[0062] In the cell structure of the embodiment of the present disclosure, the specific structures of the positive electrode sheet 10, the negative electrode sheet 20 and the solid electrolyte membrane 30 are not limited and are determined according to actual conditions.

[0063] Optionally, a positive electrode sheet 10 includes a positive current collector layer 11 and a positive active material layer 12, wherein the positive active material layer 12 is arranged on the positive current collector layer 11. The positive active material layer 12 is covered on one or both sides of the positive current collector layer 11, depending on actual needs.

[0064] In this embodiment, the positive electrode current collector layer 11 is typically made of a metal material. Optionally, the material of the positive electrode current collector layer 11 includes aluminum foil. The thickness of the positive electrode current collector layer 11 can be controlled to be 6 to 20 μm. Optionally, the thickness of the positive electrode current collector layer 11 is 10 to 20 μm. Optionally, the positive electrode current collector layer 11 includes aluminum foil with a thickness of 10 to 20 μm.

[0065] Optionally, the positive electrode active material layer 12 is obtained by coating a positive electrode active slurry onto a negative electrode current collector, rolling it, and drying it; wherein the positive electrode active slurry includes: a positive electrode material, a solid electrolyte, a conductive agent, and a binder in a weight ratio of (70-80):(10-30):(1-3):(0-4). The positive electrode material is mainly composed of one or more complexes selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium-rich manganese base, lithium manganese iron phosphate, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium vanadium phosphate, sulfur, lithium sulfide, and sulfur iodide. The solid electrolyte, conductive agent, and binder are not limited.

[0066] Optionally, a negative electrode sheet 20 includes a negative electrode active material layer 21 and a negative electrode current collector layer 22, wherein the negative electrode active material layer 21 is disposed on the negative electrode current collector layer 22. The negative electrode active material layer 21 is covered on one or both sides of the negative electrode current collector layer 22, depending on actual needs.

[0067] In this embodiment, the negative electrode current collector layer 22 is typically made of a metal material. Optionally, the negative electrode current collector layer 22 includes copper foil. The thickness of the negative electrode current collector layer 22 can be controlled to be 6-10 μm. Optionally, the thickness of the negative electrode current collector layer 22 is 6-8 μm. Optionally, the negative electrode current collector layer 22 includes copper foil with a thickness of 6-10 μm.

[0068] The negative electrode active material layer 21 is not limited and is determined according to actual needs. The negative electrode active material layer 21 includes a negative electrode material, a solid electrolyte, a conductive agent and a binder, and the mass ratio of each substance is (70-80): (10-30): (1-3): (0-4). Optionally, the negative electrode material is a silicon-based material, and the silicon-based material contains at least one of silicon element, silicon-carbon material, and silicon-oxygen material. The conductive agent is at least one of Super p and VGCF. The binder is at least one of PVDF-HFP, HNBR, PIB, and SEBS. The solid electrolyte is the same as the solid electrolyte in the solid electrolyte membrane described below.

[0069] Alternatively, a negative electrode plate includes a negative active material layer. Specifically, the negative electrode plate of this embodiment consists solely of the negative active material layer 21. The negative active material layer 21 is designed to reversibly accommodate and release lithium ions and function as an external conductor, eliminating the need for the negative current collector layer 22 to provide a conductive function. In this case, the negative active material layer 21 is composed of a composite of one or more conductive materials, such as lithium metal and carbon materials.

[0070] In the battery cell of the embodiment of the present disclosure, the solid electrolyte membrane 30 connects the negative electrode active material layer 21 and the positive electrode active material layer 12 to each other, providing the function of lithium ion transmission. The solid electrolyte membrane 30 includes one or more composites of components such as sulfide electrolyte, oxide electrolyte, polymer electrolyte and halide electrolyte. Preferably, the solid electrolyte membrane 30 is a sulfide electrolyte selected from one or more of lithium phosphorus chlorosulfur, lithium phosphorus bromine sulfur, lithium phosphorus iodine sulfur, lithium phosphorus silicon sulfur, lithium phosphorus aluminum sulfur, lithium phosphorus germanium sulfur, lithium phosphorus boron sulfur, lithium phosphorus sulfur, lithium silicon sulfur, and lithium silicon indium sulfur. Optionally, the sulfide electrolyte is preferably one or more of LGPS, LPS, Li6PS5X, and LiSiPSX, wherein X is selected from at least one of F, Cl, Br, and I.

[0071] Combine Figures 1 to 5 As shown, the embodiment of the present disclosure provides a method for preparing a solid-state battery cell, comprising the following steps:

[0072] S110, preparing a positive electrode sheet, a negative electrode sheet and a solid electrolyte membrane;

[0073] S120, alternately stacking positive electrode sheets and negative electrode sheets, and disposing a solid electrolyte membrane between adjacent positive electrode sheets and negative electrode sheets to obtain a battery cell;

[0074] Among them, the positive electrode plate includes a positive electrode composite plate with a pressure-sensitive adhesive packaging layer provided in its hollow foil area; or, the negative electrode plate includes a negative electrode composite plate with a pressure-sensitive adhesive packaging layer provided on the surface of its overhang area; or, the negative electrode plate includes a negative electrode combination plate with a solid electrolyte membrane transferred thereon and a pressure-sensitive adhesive packaging layer provided on the surface of the solid electrolyte membrane corresponding to the overhang area; a pressure-sensitive adhesive packaging layer is provided in the void area corresponding to the overhang area; the pressure-sensitive adhesive of the pressure-sensitive adhesive packaging layer includes a solvent-based pressure-sensitive adhesive.

[0075] In the preparation method of the battery cell of the embodiment of the present disclosure, a pressure-sensitive adhesive packaging layer is pre-arranged on the positive electrode sheet, the negative electrode sheet or the negative electrode sheet with a solid electrolyte membrane transferred thereon, and then the positive electrode sheet, the negative electrode sheet and the solid electrolyte membrane are stacked. During the stacking process, the pre-arranged pressure-sensitive adhesive packaging layer has a certain viscosity, thereby ensuring that the layers are aligned and not shifted during the stacking process, thereby obtaining a stacking structure in which the positive electrode sheet and the negative electrode sheet are aligned and there is no misalignment, and then the stacking structure is pressed to obtain the solid-state battery cell of the embodiment of the present disclosure. In the prepared battery cell, the pressure-sensitive adhesive packaging layer 40 completely fills the gap area, effectively isolating the positive electrode plate 10 from the negative electrode plate 20, and the pressure-sensitive adhesive packaging layer 40 uses pressure-sensitive adhesive material as the packaging layer material. The pressure-sensitive adhesive material has certain ductility and viscosity. Therefore, when the electrode material of the solid-state battery produces a volume change during the charge and discharge cycle, the pressure-sensitive adhesive uses its viscosity and ductility to adapt to the volume change of the electrode material, that is, the pressure-sensitive adhesive packaging layer can follow the volume change of the electrode material, and there will be no interface separation between the pressure-sensitive adhesive packaging layer and the electrode material / electrode plate, thereby effectively avoiding contact between the positive and negative electrodes, and then effectively preventing battery short circuit and improving the battery cycle performance.

[0076] In step S110 of the embodiment of the present disclosure, the preparation method and specific structure of the positive electrode sheet, the negative electrode sheet and the solid electrolyte membrane are not limited and can be determined according to actual conditions.

[0077] In some embodiments, when the positive electrode sheet is a composite positive electrode sheet, preparing the positive electrode sheet (composite positive electrode sheet) includes applying an acrylate pressure-sensitive adhesive encapsulation slurry to the hollow foil area of ​​the positive electrode sheet, and then performing a polymerization reaction at a polymerization temperature to obtain the composite positive electrode sheet. Optionally, the acrylate pressure-sensitive adhesive encapsulation slurry is applied to the hollow foil area of ​​the positive electrode sheet by 3D printing or screen printing.

[0078] In some embodiments, when the negative electrode plate is a negative electrode composite plate, preparing the negative electrode plate (negative electrode composite plate) includes applying an acrylate pressure-sensitive adhesive encapsulation slurry to the surface of the negative electrode plate in the overhang region, and then performing a polymerization reaction at a polymerization temperature to obtain the negative electrode composite plate. Optionally, the acrylate pressure-sensitive adhesive encapsulation slurry is applied to the surface of the negative electrode plate in the overhang region by 3D printing or screen printing.

[0079] In some embodiments, when the negative electrode sheet is a negative electrode combination sheet, preparing the negative electrode sheet (negative electrode combination sheet) includes: transferring a solid electrolyte membrane to the surface of the negative electrode sheet, applying an acrylate-type pressure-sensitive adhesive encapsulation slurry to the surface of the solid electrolyte membrane corresponding to the overhang area, and then performing a polymerization reaction at a polymerization temperature to obtain the negative electrode combination sheet. Optionally, the acrylate-type pressure-sensitive adhesive encapsulation slurry is applied to the surface of the solid electrolyte membrane corresponding to the overhang area of ​​the negative electrode combination sheet by 3D printing or screen printing.

[0080] During the preparation of the aforementioned positive and negative electrode sheets, the acrylate-based pressure-sensitive adhesive encapsulation slurry comprises, by weight, 35% to 60% acrylate monomer, 0.1% to 5% initiator, and 35% to 60% solvent. The acrylate monomers include hard monomers and soft monomers, with the mass ratio of hard monomer to soft monomer being 0.2 to 5. The hard monomers include methyl acrylate and / or methyl methacrylate, and the soft monomers include one or more of ethyl acrylate, n-butyl acrylate, and n-butyl methacrylate. The types and mass ratio of the hard and soft monomers, as well as the selection and dosage of the initiator and solvent, are determined based on actual conditions. For details on the acrylate-based pressure-sensitive adhesive encapsulation slurry, please refer to the aforementioned related information.

[0081] Optionally, the acrylate pressure-sensitive adhesive encapsulation slurry includes 50% acrylate monomer, 0.5% initiator and 49.5% solvent according to mass percentage, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5.

[0082] In the disclosed embodiments, the 3D printing parameters are not limited and are determined according to actual needs. Optionally, the inner diameter of the printing needle is 0.2 to 2 mm, the printing speed is 5 to 80 mm / s, and the printing layer height is 10 μm to 200 μm.

[0083] The printing parameters of the screen printing are not limited and are determined according to actual needs. Optionally, the printing thickness is 10μm to 200μm, and the printing width is determined according to the size of the packaging area (i.e., the overhang area).

[0084] In some embodiments, 3D printing or screen printing is used to place an acrylate pressure-sensitive adhesive encapsulation slurry at corresponding locations, including: gradually placing multiple acrylate pressure-sensitive adhesive encapsulation slurries having increasing mass ratios of hard monomers to soft monomers at corresponding locations using 3D printing or screen printing, from the inside outward, to obtain a pressure-sensitive adhesive encapsulation layer having a viscosity that decreases from the inside outward. The corresponding locations include the bare foil area of ​​the positive electrode sheet, the electrode surface of the overhang area of ​​the negative electrode sheet, or the solid electrolyte membrane surface corresponding to the overhang area of ​​the negative electrode combination sheet.

[0085] Optionally, in the plurality of acrylate-based pressure-sensitive adhesive encapsulation slurries having increasing mass ratios of hard monomer to soft monomer, the mass ratio of the hard monomer to the soft monomer is 0.2 to 5. Parameters such as the types and mass ratio of the hard and soft monomers, as well as the selection and amount of the initiator and solvent, are determined based on actual conditions.

[0086] In some embodiments, acrylate pressure-sensitive adhesive encapsulation slurry is set at a corresponding position by 3D printing or screen printing; comprising: gradually setting a first acrylate pressure-sensitive adhesive encapsulation slurry and a second acrylate pressure-sensitive adhesive encapsulation slurry at corresponding positions by 3D printing or screen printing from the inside to the outside, to obtain a pressure-sensitive adhesive encapsulation layer including a pressure-sensitive adhesive encapsulation inner layer and a pressure-sensitive adhesive encapsulation outer layer, and the viscosity of the pressure-sensitive adhesive encapsulation inner layer is greater than the viscosity of the pressure-sensitive adhesive encapsulation outer layer; wherein the mass ratio of the hard monomer to the soft monomer in the first acrylate pressure-sensitive adhesive encapsulation slurry is less than the mass ratio of the hard monomer to the soft monomer in the second acrylate pressure-sensitive adhesive encapsulation slurry.

[0087] Optionally, the mass ratio of the hard monomer to the soft monomer in the first acrylate-based pressure-sensitive adhesive encapsulation slurry is 0.5 to 2. The mass ratio of the hard monomer to the soft monomer in the second acrylate-based pressure-sensitive adhesive encapsulation slurry is 2 to 5. Parameters such as the type and mass ratio of the hard and soft monomers in the acrylate-based pressure-sensitive adhesive encapsulation slurry, as well as the selection and amount of the initiator and solvent, are determined based on actual conditions, as long as the viscosity of the inner pressure-sensitive adhesive encapsulation layer is greater than that of the outer pressure-sensitive adhesive encapsulation layer.

[0088] An embodiment of the present disclosure provides a solid-state battery, comprising a solid-state battery cell according to any of the preceding embodiments; or a cell prepared by the method for preparing a solid-state battery cell according to any of the preceding embodiments.

[0089] The following specific examples are given to specifically illustrate the solid-state battery cell and its preparation method and solid-state battery of the embodiments of the present disclosure, so as to more clearly illustrate the technical problems, technical solutions and beneficial effects solved by the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications.

[0090] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0091] Example 1

[0092] Combine Figures 1 to 3 As shown, a solid-state battery cell includes: alternatingly stacked positive electrode sheets 10 and negative electrode sheets 20, and a solid electrolyte membrane 30 is arranged between adjacent positive electrode sheets 10 and negative electrode sheets 20; the circumferential direction of the negative electrode sheets 20 exceeds the positive electrode sheets to form an overhang area 200; wherein, a pressure-sensitive adhesive packaging layer 40 is provided in the gap area corresponding to the overhang area 200; the pressure-sensitive adhesive of the pressure-sensitive adhesive packaging layer 40 includes an acrylate pressure-sensitive adhesive.

[0093] Combine Figure 6 As shown, the solid-state battery cell of this embodiment 1 is prepared by the following steps:

[0094] S101. Prepare positive electrode sheets, negative electrode sheets and solid electrolyte membranes.

[0095] S102. Transfer the solid electrolyte membrane to both surfaces of the negative electrode plate. Print an acrylic ester pressure-sensitive adhesive encapsulation slurry on the surface of the solid electrolyte membrane corresponding to the overhang area using a 3D printing method to obtain a 4 mm × 4 mm slurry frame. Then, perform a polymerization reaction at a polymerization temperature for a preset time, remove the solvent, and obtain a negative electrode assembly plate with a pressure-sensitive adhesive encapsulation layer printed on the overhang area. In the 3D printing method, the inner diameter of the printing needle is 1 mm, the printing speed is 45 to 80 mm / s, and the printing layer height is 100 μm to 200 μm.

[0096] S103, alternately stacking the positive electrode sheets prepared in step S101 and the negative electrode combination sheets obtained in step S102 to obtain a laminate structure;

[0097] S104: isostatically pressing the laminated structure to obtain a battery cell. The isostatic pressing pressure is 500 MPa, and the holding time is 5 minutes.

[0098] In this embodiment 1, for the subsequent solid-state battery assembly and battery performance testing, the following negative electrode sheet, positive electrode sheet and solid electrolyte membrane are specifically used.

[0099] The negative electrode sheet is prepared using a wet process. The negative electrode active material layer is obtained by coating the negative electrode slurry onto the negative electrode current collector layer, then rolling and drying it. The negative electrode slurry consists of porous silicon (the negative electrode active material), Li6PS5Cl sulfide solid electrolyte, conductive carbon, SEBS binder, and anisole solvent in a weight ratio of 70:25:2:3, mixed to achieve a fluid negative electrode slurry. The negative electrode current collector layer uses 6-10 μm copper foil. The negative electrode sheet measures 105 mm x 75 mm.

[0100] Positive electrode sheet: The positive electrode active material layer is prepared by a wet process. The positive electrode active material layer is obtained by coating the positive electrode slurry on the positive electrode current collector layer, rolling and drying it. The positive electrode slurry includes: positive electrode active material LiNi in a weight ratio of 70:26:2:2 0.8 Co 0.1 Mn 0.1 O2, Li6PS5Cl sulfide solid electrolyte, conductive carbon, SEBS binder, and anisole solvent are mixed to create a positive electrode slurry with a certain degree of fluidity. The positive electrode current collector layer uses 10-20 μm aluminum foil. The positive electrode sheet measures 100 mm × 70 mm.

[0101] Solid electrolyte membrane: Li6PS5Cl sulfide solid electrolyte and SEBS binder in a mass ratio of 98:2 were mixed with anisole solvent to obtain an electrolyte slurry, and the electrolyte slurry was coated on a current collector to obtain a solid electrolyte membrane.

[0102] In step S102 of Example 1, the acrylate pressure-sensitive adhesive encapsulation slurry includes 50% acrylate monomer, 0.5% initiator azobisisobutyronitrile, and 49.5% solvent. The acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5. Based on the types of the hard monomer and the soft monomer and their mass ratio, encapsulation slurries I to V as described in Table 1 were obtained.

[0103] Table 1

[0104]

[0105] In step S102 of this embodiment 1, the above-mentioned encapsulation slurries I to V are respectively printed on the surface of the solid electrolyte membrane corresponding to the overhang area to obtain a slurry frame, and then a polymerization reaction is carried out at a polymerization temperature of 65°C for 1 to 2 hours, and the solvent is removed to obtain negative electrode combination pole pieces I to negative electrode combination pole pieces V respectively; and then battery cells I to V are correspondingly obtained.

[0106] Example 2

[0107] Combine Figure 4 As shown, a solid-state battery cell comprises: alternating positive and negative electrode sheets, with a solid electrolyte membrane disposed between adjacent positive and negative electrode sheets; the negative electrode sheets extend circumferentially beyond the positive electrode sheets to form an overhang region; a pressure-sensitive adhesive encapsulation layer is disposed in the gap corresponding to the overhang region; the pressure-sensitive adhesive of the pressure-sensitive adhesive encapsulation layer comprises an acrylate-type pressure-sensitive adhesive. The viscosity of the pressure-sensitive adhesive encapsulation layer decreases from the inside to the outside.

[0108] The method for preparing the solid-state battery cell of this embodiment 2 is different from that of embodiment 1 in that, in step S102, an acrylate-type pressure-sensitive adhesive encapsulation slurry is printed on the surface of the solid electrolyte membrane corresponding to the overhang area by a 3D printing method, comprising: gradually disposing a plurality of acrylate-type pressure-sensitive adhesive encapsulation slurries having increasing mass ratios of hard monomers to soft monomers on the surface of the solid electrolyte membrane corresponding to the overhang area by 3D printing from the inside to the outside, to obtain a pressure-sensitive adhesive encapsulation layer having a viscosity that decreases from the inside to the outside.

[0109] Specifically, from the inside to the outside, the first acrylate pressure-sensitive adhesive encapsulation slurry and the second acrylate pressure-sensitive adhesive encapsulation slurry are gradually arranged on the surface of the solid electrolyte membrane corresponding to the overhang area by 3D printing to obtain a pressure-sensitive adhesive encapsulation layer 40 including a pressure-sensitive adhesive encapsulation inner layer 41 and a pressure-sensitive adhesive encapsulation outer layer 42, and the viscosity of the pressure-sensitive adhesive encapsulation inner layer 41 is greater than the viscosity of the pressure-sensitive adhesive encapsulation outer layer 42; wherein, the mass ratio of the hard monomer to the soft monomer in the first acrylate pressure-sensitive adhesive encapsulation slurry is less than the mass ratio of the hard monomer to the soft monomer in the second acrylate pressure-sensitive adhesive encapsulation slurry.

[0110] In this embodiment 2, the first acrylate pressure-sensitive adhesive encapsulation slurry and the second acrylate pressure-sensitive adhesive encapsulation slurry are respectively the encapsulation slurries in Table 1 of embodiment 1, and corresponding battery cells VI to VIII as described in the following Table 2 are obtained.

[0111] Table 2

[0112]

[0113] Comparative Example 1

[0114] Solid-state battery cell Comparison I of this Comparative Example 1 differs from Example 1 in that, in step S102, only the solid electrolyte membrane is transferred to both surfaces of the negative electrode sheet, without 3D printing, to obtain the negative electrode sheet with the solid electrolyte membrane transferred thereto. The remaining steps and parameters are the same as in Example 1.

[0115] The battery cell comparison I obtained in comparative example 1 is a battery cell without a pressure-sensitive adhesive packaging layer.

[0116] Comparative Example 2

[0117] Solid-state battery cell comparison II of this comparative example 2 differs from that of Example 1 in that, in step S102, the acrylate pressure-sensitive adhesive encapsulation slurry is replaced with the following solid electrolyte slurry, which is dried at 80°C for 2 hours to obtain negative electrode assembly electrode sheet comparison II, and further obtain battery cell comparison II. The solid electrolyte slurry comprises a mixed slurry of anisole, Li6PS5Cl, and polyvinylidene fluoride (SEBS) binder in a mass ratio of 45:50:5. The remaining steps and parameters are the same as those of Example 1.

[0118] Comparative Example 3

[0119] Solid-state battery cell comparison III of this comparative example 2 differs from that of Example 1 in that, in step S102, an ethylene-vinyl acetate copolymer (EVA) hot melt adhesive heated to 100°C is used instead of the acrylic pressure-sensitive adhesive encapsulation slurry, and then cured and dried to obtain negative electrode assembly comparison sheet III, and thus obtain battery cell comparison III. The remaining steps and parameters are the same as those of Example 1.

[0120] Comparative Example 4

[0121] Solid-state battery cell Comparative IV of this comparative example 4 differs from that of Example 1 in that, in step S102, epoxy acrylic resin light-curing adhesive is used instead of the acrylate pressure-sensitive adhesive encapsulation slurry, and the resulting product is irradiated with ultraviolet light for 30 seconds, thereby obtaining negative electrode assembly Comparative III, and further obtaining cell Comparative IV. The remaining steps and parameters are the same as those of Example 1.

[0122] The battery cells I to VIII, and the battery cells comparison I to battery cell comparison IV prepared in the above-mentioned Examples 1 and 2 were further assembled to obtain solid-state batteries I to VIII, and solid-state battery comparison I to solid-state battery comparison IV, respectively, and battery yield tests and cycle performance tests were carried out.

[0123] The cell yield test is a charge and discharge test of the battery after isostatic pressing. The yield is obtained by dividing the number of batteries that pass the test by the total number of tested batteries. The test results are shown in Table 3.

[0124] The cycle performance test is to charge and discharge the solid-state battery at a rate of 0.33C at 25°C, with a voltage range of 2.5 to 4.25V, and cycle charge and discharge 200 times. The first discharge capacity and the 200th discharge capacity of the battery are recorded. The capacity retention rate after 200 cycles is obtained by dividing the 200th discharge capacity by the first discharge capacity. The test results are shown in Table 3.

[0125] Table 3

[0126]

[0127] The results in Table 3 show that compared to solid-state battery comparison I, which does not have a pressure-sensitive adhesive encapsulation layer, the yield and cycle performance of solid-state batteries I to VIII using a pressure-sensitive adhesive as the overhang area encapsulation material are significantly improved. This is because the acrylate-based pressure-sensitive adhesive material can fix the electrode layer and the solid electrolyte membrane, preventing the active material and electrolyte in the middle from expanding or shifting. In addition, the acrylate-based pressure-sensitive adhesive material has a certain viscosity. When the solid-state lithium-ion battery is pressurized, the positive and negative electrodes are bonded together through the pressure-sensitive adhesive material. This pressure-sensitive adhesive material not only fixes the positive and negative electrodes, preventing them from deforming under high pressure, which could lead to contact between the positive and negative electrode edges, preventing misalignment of the positive and negative electrodes, and avoiding short circuits during battery preparation, significantly improving the yield of solid-state lithium-ion battery production, but also suppresses the expansion of various components of the solid-state lithium-ion battery electrodes during the charge and discharge process, thereby effectively improving the battery's cycle performance.

[0128] By setting multiple acrylate pressure-sensitive adhesive encapsulation slurries with increasing mass ratios of hard monomers to soft monomers on the surface of the solid electrolyte membrane corresponding to the overhang area, a pressure-sensitive adhesive encapsulation layer with decreasing viscosity and increasing hardness from the inside to the outside is obtained, which can further improve the performance of the solid-state battery. Therefore, the solid-state battery VI has the highest yield and the best cycle retention rate.

[0129] The 200-cycle capacity retention rate of solid-state batteries II to IV is lower than that of solid-state batteries I to VIII using acrylate-type pressure-sensitive adhesive as the overhang packaging layer. This is because the pressure-sensitive adhesive material encapsulated in the overhang area bonds the positive and negative electrodes together when the solid-state lithium-ion battery is pressurized, alleviating the interface contact failure caused by the volume change of the electrode in the solid-state lithium-ion battery. Although the use of solid electrolytes, hot melt adhesives, light-curing adhesives and other materials can fill the overhang area to improve battery yield, they have low viscosity and cannot effectively suppress the expansion of various components during the charge and discharge process, resulting in poor battery cycle performance.

[0130] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process and other changes. The embodiments represent only possible variations. Unless expressly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. Moreover, the terms used in this application are only used to describe the embodiments and are not used to limit the claims. As used in the description of the embodiments and claims, the singular forms "a", "an" and "the" are intended to also include the plural forms unless the context clearly indicates otherwise. Similarly, the term "and / or" as used in this application means any and all possible combinations of one or more of the associated listings. In addition, when used in this application, the term "comprise" and its variations "comprises" and / or comprising refer to the presence of stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof. In the absence of further restrictions, an element defined by the sentence "comprising a..." does not exclude the presence of other identical elements in the process, method or device that includes the element. In this article, each embodiment may focus on the differences from other embodiments, and the same and similar parts between the various embodiments can be referenced to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiments, then the relevant parts can be referred to the description of the method part.

[0131] Those skilled in the art will appreciate that the units and steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software may depend on the specific application and design constraints of the technical solution. The technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present disclosure. The technicians will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0132] The flowcharts and block diagrams in the accompanying drawings show the possible implementation architectures, functions and operations of the systems, methods and computer program products according to the embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment or part of the code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical functions. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A solid-state battery cell, characterized in that: include: Positive and negative electrode sheets are alternately stacked, and a solid electrolyte membrane is provided between adjacent positive and negative electrode sheets; at least one side of the negative electrode sheet extends beyond the positive electrode sheet to form an overhang region; wherein a pressure-sensitive adhesive encapsulation layer is provided in a gap region corresponding to the overhang region; the pressure-sensitive adhesive of the pressure-sensitive adhesive encapsulation layer comprises a solvent-based pressure-sensitive adhesive; The pressure-sensitive adhesive packaging layer completely fills the gap area; the pressure-sensitive adhesive packaging layer has a viscosity that decreases from the inside to the outside, the inside being the side close to the battery cell and the outside being the side away from the battery cell; The pressure-sensitive adhesive encapsulation layer is obtained by in-situ polymerization of an acrylate-type pressure-sensitive adhesive encapsulation slurry arranged in the gap area corresponding to the overhang area; wherein the acrylate-type pressure-sensitive adhesive encapsulation slurry includes an acrylate monomer, an initiator and a solvent, and the acrylate monomer includes a hard monomer and a soft monomer.

2. The solid-state battery cell according to claim 1, characterized in that: According to the percentage by mass, the acrylate type pressure-sensitive adhesive encapsulation paste includes 35% to 60% of acrylate monomer, 0.1% to 5% of initiator and 35% to 60% of solvent, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5; or, According to the percentage by mass, the acrylate type pressure-sensitive adhesive encapsulation slurry includes 43% to 55% of a pressure-sensitive adhesive material, 0.1% to 2% of an initiator, and 43% to 55% of a solvent, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5; or, According to the percentage by mass, the acrylate type pressure-sensitive adhesive encapsulation slurry includes 48% to 52% of a pressure-sensitive adhesive material, 0.1% to 1% of an initiator, and 48% to 52% of a solvent, wherein the acrylate monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5; or, According to the mass percentage, the acrylic pressure-sensitive adhesive encapsulation slurry includes 50% pressure-sensitive adhesive material, 0.1% to 1% initiator and 49% to 49.9% solvent, wherein the acrylic ester monomer includes a hard monomer and a soft monomer, and the mass ratio of the hard monomer to the soft monomer is 0.2 to 5.

3. The solid-state battery cell according to claim 2, characterized in that: In the acrylic ester pressure-sensitive adhesive encapsulation slurry, the mass ratio of the hard monomer to the soft monomer is 0.25-5; or, the mass ratio of the hard monomer to the soft monomer is 0.5-5; or, the mass ratio of the hard monomer to the soft monomer is 1-5; or, the mass ratio of the hard monomer to the soft monomer is 2-5; or, the mass ratio of the hard monomer to the soft monomer is 3-5.

4. The solid-state battery cell according to claim 1, characterized in that: Hard monomers include methyl acrylate and / or methyl methacrylate; and / or The soft monomer includes one or more of ethyl acrylate, n-butyl acrylate and n-butyl methacrylate; and / or Initiators include azobisisobutyronitrile and / or benzoyl peroxide; and / or The solvent includes one or more of N-methylpyrrolidone, isopropyl alcohol, toluene and xylene.

5. The solid-state battery cell according to any one of claims 1 to 4, characterized in that: The pressure-sensitive adhesive packaging layer comprises a pressure-sensitive adhesive packaging inner layer and a pressure-sensitive adhesive packaging outer layer, wherein the viscosity of the pressure-sensitive adhesive packaging inner layer is greater than the viscosity of the pressure-sensitive adhesive packaging outer layer.

6. The solid-state battery cell according to claim 5, characterized in that: When the pressure-sensitive adhesive encapsulation layer is obtained by in-situ polymerization of an acrylate pressure-sensitive adhesive encapsulation slurry arranged in a gap area corresponding to the overhang area, the mass ratio of the hard monomer to the soft monomer in the acrylate pressure-sensitive adhesive encapsulation slurry used for the pressure-sensitive adhesive encapsulation layer increases from the inside to the outside.

7. A method for preparing a solid-state battery cell according to any one of claims 1 to 6, characterized in that: include: Prepare positive electrode sheets, negative electrode sheets and solid electrolyte membranes; Alternately stacking positive electrode sheets and negative electrode sheets, and providing a solid electrolyte membrane between adjacent positive electrode sheets and negative electrode sheets to obtain a battery cell; Among them, the positive electrode plate includes a positive electrode composite plate with a pressure-sensitive adhesive packaging layer provided in its hollow foil area; or, the negative electrode plate includes a negative electrode composite plate with a pressure-sensitive adhesive packaging layer provided on the surface of its overhang area; or, the negative electrode plate includes a negative electrode combination plate with a solid electrolyte membrane transferred thereon and a pressure-sensitive adhesive packaging layer provided on the surface of the solid electrolyte membrane corresponding to the overhang area; a pressure-sensitive adhesive packaging layer is provided in the void area corresponding to the overhang area; the pressure-sensitive adhesive of the pressure-sensitive adhesive packaging layer includes a solvent-type pressure-sensitive adhesive; wherein the pressure-sensitive adhesive packaging layer has a viscosity that decreases from the inside to the outside; and the pressure-sensitive adhesive packaging layer is obtained by in-situ polymerization of an acrylate-type pressure-sensitive adhesive packaging slurry provided in the void area corresponding to the overhang area; wherein the acrylate-type pressure-sensitive adhesive packaging slurry includes an acrylate monomer, an initiator and a solvent, and the acrylate monomer includes a hard monomer and a soft monomer.

8. The preparation method according to claim 7, characterized in that When the positive electrode sheet is a positive electrode composite sheet, the positive electrode composite sheet is prepared, including: The acrylate pressure-sensitive adhesive encapsulation slurry is placed on the empty foil area of ​​the positive electrode plate, and then a polymerization reaction is carried out at a polymerization temperature to obtain a positive electrode composite plate; When the negative electrode plate adopts a negative electrode composite plate, preparing the negative electrode composite plate includes: The acrylate pressure-sensitive adhesive encapsulation slurry is placed on the surface of the negative electrode in the overhang area, and then a polymerization reaction is carried out at a polymerization temperature to obtain a negative electrode composite electrode; When the negative electrode plate adopts a negative electrode combination plate, preparing the negative electrode combination plate includes: The solid electrolyte membrane is transferred to the surface of the negative electrode plate, and the acrylic ester pressure-sensitive adhesive encapsulation slurry is set on the surface of the solid electrolyte membrane corresponding to the overhang area, and then a polymerization reaction is carried out at a polymerization temperature to obtain a negative electrode assembly plate.

9. The preparation method according to claim 8, characterized in that The acrylic ester pressure-sensitive adhesive encapsulation slurry is set at the corresponding position by 3D printing or screen printing; the corresponding position includes the empty foil area of ​​the positive electrode sheet, the electrode surface of the overhang area of ​​the negative electrode sheet, or the solid electrolyte membrane surface corresponding to the overhang area of ​​the negative electrode combination electrode sheet.

10. The preparation method according to claim 9, characterized in that The acrylic pressure-sensitive adhesive encapsulation paste is set at the corresponding position by 3D printing or screen printing, including: From the inside to the outside, a plurality of acrylate type pressure-sensitive adhesive encapsulation pastes having a mass ratio of hard monomer to soft monomer is gradually placed at corresponding positions by 3D printing or screen printing to obtain a pressure-sensitive adhesive encapsulation layer having a viscosity that decreases from the inside to the outside; or From the inside to the outside, the first acrylate pressure-sensitive adhesive encapsulation slurry and the second acrylate pressure-sensitive adhesive encapsulation slurry are gradually arranged at corresponding positions by 3D printing or screen printing to obtain a pressure-sensitive adhesive encapsulation layer including an inner pressure-sensitive adhesive encapsulation layer and an outer pressure-sensitive adhesive encapsulation layer, and the viscosity of the inner pressure-sensitive adhesive encapsulation layer is greater than the viscosity of the outer pressure-sensitive adhesive encapsulation layer; wherein the mass ratio of the hard monomer to the soft monomer in the first acrylate pressure-sensitive adhesive encapsulation slurry is less than the mass ratio of the hard monomer to the soft monomer in the second acrylate pressure-sensitive adhesive encapsulation slurry.

11. The preparation method according to claim 10, characterized in that: In a plurality of acrylate pressure-sensitive adhesive encapsulation slurries having increasing mass ratios of hard monomers to soft monomers, the mass ratios of the hard monomers to the soft monomers are 0.2 to 5; or, The mass ratio of the hard monomer to the soft monomer in the first acrylate pressure-sensitive adhesive encapsulation slurry is 0.5-2; the mass ratio of the hard monomer to the soft monomer in the second acrylate pressure-sensitive adhesive encapsulation slurry is 2-5.

12. A solid-state battery, characterized in that: A solid-state battery cell according to any one of claims 1 to 6 or a cell prepared by the method for preparing a solid-state battery cell according to any one of claims 7 to 11.

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