Solid-state battery cell and preparation method therefor, battery device, and electric device

Abstract

Disclosed in the present application are a solid-state battery cell and a preparation method therefor, a battery device, and an electric device. The battery cell comprises an electrode assembly. The electrode assembly comprises a main body portion and a tab portion extending from the main body portion. The main body portion comprises a positive electrode sheet, a negative electrode sheet, and a solid-state electrolyte membrane that are stacked. The solid-state electrolyte membrane is located between the positive electrode sheet and the negative electrode sheet. The main body portion is covered with an adhesive film having an elastic modulus of 1000 N / mm2-10,000 N / mm2. The battery cell provided by the embodiments of the present application exhibits an improved cycle performance.

Description

Solid-state battery cells and their preparation methods, battery devices, and electrical devices.

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411803652.9, filed on December 09, 2024, entitled "Solid-state battery cell and preparation method thereof, battery device, power device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, specifically to a solid-state battery cell and its preparation method, battery device, and power-consuming device. Background Technology

[0004] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric car toys, electric toy ships, electric toy airplanes, and power tools.

[0005] In the development of solid-state battery cells, improving the cycle performance of solid-state battery cells is one of the urgent problems to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a solid-state battery cell, its preparation method, a battery device, and an electrical device.

[0007] In a first aspect, embodiments of this application provide a solid-state battery cell. The battery cell includes an electrode assembly, which includes a main body and tabs extending from the main body. The main body includes a positive electrode, a negative electrode, and a solid electrolyte membrane stacked together. The solid electrolyte membrane is located between the positive and negative electrode. The main body is covered with an adhesive film, and the elastic modulus of the adhesive film is 1000 N / mm². 2 -10000N / mm 2 .

[0008] According to embodiments of this application, by coating the main body of the electrode assembly with a layer of adhesive film with a high elastic modulus, the adhesive film can provide a high clamping force to the electrode assembly. During the charge-discharge cycle of the battery cell, the adhesive film can provide a clamping force opposite to the expansion direction to suppress the expansion of the battery cell, thereby reducing the gaps inside the battery cell, reducing the impact of battery cell expansion on the solid-solid contact interface between the solid electrolyte membrane and the positive and negative electrode plates, improving the transport effect of active ions, and thus improving the cycle performance of the battery cell. In addition, coating the main body of the electrode assembly with an adhesive film can achieve a better isolation effect, reducing the contact between the water-containing solid electrolyte membrane and water vapor, thereby reducing the side reactions of the solid electrolyte, reducing electrolyte consumption, and further improving the cycle performance of the battery cell.

[0009] In some embodiments, the thickness of the adhesive film is from 80 μm to 1000 μm.

[0010] In some embodiments, the material of the adhesive film includes one or more of epoxy resin, polypropylene, polyacrylate, epoxy acrylate, polyurethane acrylate, and polystyrene.

[0011] In some embodiments, the Shore hardness of the adhesive film is 50 HD to 200 HD.

[0012] In some embodiments, the compressive strength of the adhesive film is 5 kg / mm². 2 Up to 100kg / mm 2 .

[0013] In some embodiments, the water absorption rate of the film at 25°C for 24 hours is less than or equal to 0.1%.

[0014] In some embodiments, the solid-state battery cell has an expansion rate of 0.3%-5% after 900 charge-discharge cycles.

[0015] Secondly, embodiments of this application provide a method for preparing a solid-state battery cell, comprising the following steps:

[0016] An electrode assembly is provided, the electrode assembly including a positive electrode, a negative electrode, and a solid electrolyte membrane, the solid electrolyte membrane being located between the positive electrode and the negative electrode; the electrode assembly includes a main body and a tab extending from the main body;

[0017] The electrode assembly is immersed in adhesive to coat the surface of the main body to form an adhesive coating layer.

[0018] The adhesive coating layer is cured to form an adhesive film covering the main body.

[0019] In some embodiments, the adhesive includes one or more of epoxy resin, polypropylene, polyacrylate, epoxy acrylate, polyurethane acrylate, and polystyrene.

[0020] In some embodiments, the viscosity of the adhesive is from 30 cps to 10,000 cps.

[0021] In some embodiments, the viscosity of the adhesive is between 80 cps and 5000 cps.

[0022] In some embodiments, the curing temperature is between 50°C and 500°C.

[0023] In some embodiments, the curing time is 5 to 30 minutes.

[0024] In some embodiments, the curing process includes one or more of water bath heat curing, infrared curing, ultraviolet curing, and green light curing.

[0025] In some embodiments, providing the electrode assembly includes performing isostatic pressing on the electrode assembly.

[0026] In some embodiments, the temperature of the isostatic pressing treatment is 25°C to 300°C.

[0027] In some embodiments, the pressure of the isostatic pressing process is from 100 MPa to 3000 MPa.

[0028] In some embodiments, the isostatic pressing process takes 5 to 30 minutes.

[0029] In some embodiments, the pressure transmission medium in the isostatic pressing process includes any one of water, ester, and inert gas.

[0030] Thirdly, embodiments of this application provide a battery device, including a solid-state battery cell according to the first aspect of this application.

[0031] Fourthly, embodiments of this application provide an electrical device, including the battery device of the third aspect of this application. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0033] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0034] Figure 2 is a schematic diagram of the explosion of a battery provided in some embodiments of this application.

[0035] Figure 3 is an exploded view of the battery module shown in Figure 2.

[0036] Figure 4 is a schematic diagram of the adhesive dispensing device in some embodiments of this application.

[0037] Figure 5 is a schematic diagram of the structure of the base plate in some embodiments of this application.

[0038] Figure 6 is a schematic diagram of the structure of an electrode assembly covered with an adhesive film in some embodiments of this application.

[0039] The accompanying drawings are not necessarily drawn to scale.

[0040] The reference numerals in the attached drawings are explained as follows: 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5C. Accommodation space; 6. Battery module; 7. Battery cell; 71. Electrode assembly; 8. Glue injection device; 81. Glue sleeve; 82. Glue injection groove; 83. Base plate; 831. Glue guide hole; 832. Glue guide groove. Detailed Implementation

[0041] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery device, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0042] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0043] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0044] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0045] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0046] Unless otherwise specified, in this application, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0047] In this application, the terms "multiple" or "various" refer to two or more kinds of things.

[0048] In the description of the embodiments of this application, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0050] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this application. Unless otherwise stated, the test temperature for each parameter is 25°C.

[0051] The battery device mentioned in the embodiments of this application can be a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application can include battery cells, battery modules, or battery packs.

[0052] A single battery cell is the smallest unit that makes up a battery, and it can independently perform the functions of charging and discharging. When there are multiple battery cells, they are connected in series, parallel, or mixed connections through a busbar.

[0053] In some embodiments, the battery device may be a battery module; when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0054] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0055] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0056] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0057] The technical solutions described in the embodiments of this application are applicable to battery devices and electrical devices using battery devices.

[0058] Battery devices can be used as the power source for electrical devices or as energy storage units for electrical devices. Electrical devices can be, but are not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0059] Electrical devices can choose the type of battery device according to their usage needs, such as individual battery cells, battery modules, or battery packs.

[0060] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0061] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0062] As shown in Figure 1, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0063] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0064] In some embodiments, the battery device 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0065] Figure 2 is an exploded view of a battery provided in some embodiments of this application. As shown in Figure 2, the battery device 2 includes a housing 5 and a battery cell (not shown), with the battery cell housed within the housing 5.

[0066] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0067] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0068] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0069] In battery device 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells are connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, in parallel, or in a mixed configuration, and then the whole assembly of multiple battery cells is housed in housing 5. Alternatively, multiple battery cells can first be connected in series, in parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a mixed configuration to form a whole assembly, which is then housed in housing 5.

[0070] Figure 3 is an exploded view of the battery module shown in Figure 2.

[0071] As shown in Figure 3, in some embodiments, there are multiple battery cells 7, which are first connected in series, parallel, or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0072] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0073] The battery cells mentioned in the embodiments of this application may include lithium-ion battery cells or sodium-ion battery cells.

[0074] A solid-state battery cell includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited in this regard.

[0075] Solid-state batteries are batteries that use solid materials as electrolytes. A typical solid-state battery cell includes a casing and electrode assemblies within the casing. These electrode assemblies generally include a positive electrode, a negative electrode, and a solid electrolyte membrane. The solid electrolyte membrane is located between the positive and negative electrodes, serving to isolate the positive and negative electrodes and transport active ions. Because there is no liquid material inside a solid-state battery cell, the contact between the positive and negative electrodes and the solid electrolyte is solid-solid. This contact interface has certain gaps, and solid-state batteries typically experience significant cyclic expansion during charge-discharge cycles. This cyclic expansion leads to an increase in the gaps between the solid particles and the solid electrolyte membrane and the positive and negative electrodes. This results in poor solid-solid interface contact, decreased ion transport performance, and consequently, a decrease in the internal conductivity of the solid-state battery, causing a sharp deterioration in battery performance.

[0076] In view of this, embodiments of this application provide a solid-state battery cell that improves the cycle expansion during the charging and discharging process, thereby reducing the internal voids of the battery cell and thus improving its cycle performance.

[0077] In some embodiments, the electrode assembly includes a main body and tabs extending from the main body. The main body includes a positive electrode, a negative electrode, and a solid electrolyte membrane stacked together, with the solid electrolyte membrane located between the positive and negative electrode. The main body is covered with an adhesive film having an elastic modulus of 1000 N / mm². 2 -10000N / mm 2 .

[0078] The battery cell provided in this application embodiment, by coating the main body of the electrode assembly with a layer of adhesive film with a high elastic modulus, provides a high clamping force to the electrode assembly. During the charge-discharge cycle of the battery cell, the adhesive film can provide a clamping force opposite to the expansion direction to suppress the expansion of the battery cell, thereby reducing the gaps inside the battery cell, reducing the impact of battery cell expansion on the solid-solid contact interface between the solid electrolyte membrane and the positive and negative electrode plates, improving the transport effect of active ions, and thus improving the cycle performance of the battery cell. In addition, by coating the main body of the electrode assembly with an adhesive film, a better isolation effect can be achieved, reducing the contact between the solid electrolyte membrane and water vapor, thereby reducing the side reactions of the solid electrolyte, reducing electrolyte consumption, and further improving the cycle performance of the battery cell.

[0079] The elastic modulus of the adhesive film is 1000 N / mm. 2 -10000N / mm 2 For example, it can be 1000 N / mm 21500N / mm 2 2000N / mm 2 2500N / mm 2 3000N / mm 2 3500N / mm 2 4000N / mm 2 4500N / mm 2 5000N / mm 2 5500N / mm 2 6000N / mm 2 6500N / mm 2 7000N / mm 2 7500N / mm 2 8000N / mm 2 8500N / mm 2 9000N / mm 2 9500N / mm 2 10000N / mm 2 Or any range of the above values; optionally, the elastic modulus of the adhesive film can be 1200 N / mm². 2 -8000N / mm 2 By limiting the elastic modulus of the adhesive film to the above range, the adhesive film can provide a higher clamping force to the electrode assembly, reducing the cyclic expansion of the battery cells; at the same time, the adhesive film can have a certain degree of toughness, which is beneficial for the coating of the adhesive film on the surface of the electrode assembly and reduces the cracking of the adhesive film.

[0080] In some implementations, the thickness of the adhesive film can be between 80 μm and 1000 μm. Exemplarily, the thickness of the adhesive film can be 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, or any range of the above values. Optionally, the thickness of the adhesive film can be between 100 μm and 800 μm.

[0081] By limiting the thickness of the adhesive film within the aforementioned range, the film can achieve better strength and provide higher clamping force, thereby reducing the cyclic expansion of the battery cells. A thinner film results in lower strength, posing a risk of film rupture during cyclic expansion of the battery cells; a thicker film increases the overall thickness of the battery cells, leading to an increase in the hardware volume of the battery cells and affecting the battery's energy density.

[0082] In some embodiments, the Shore hardness of the adhesive film can be 50HD-200HD. Exemplarily, the Shore hardness of the adhesive film can be 50HD, 60HD, 70HD, 80HD, 90HD, 100HD, 110HD, 120HD, 130HD, 140HD, 150HD, 160HD, 170HD, 80HD, 190HD, 200HD, or any range of the above values.

[0083] By limiting the hardness of the adhesive film to the above range, the adhesive film can have high strength, which is beneficial for the adhesive film to provide a higher clamping force to the electrode assembly, thereby reducing the expansion of the battery cell and improving the cycle performance of the battery cell.

[0084] In some embodiments, the compressive strength of the adhesive film can be 5 kg / mm². 2 -100kg / mm 2 For example, the compressive strength of the adhesive film can be 5 kg / mm². 2 10kg / mm 2 15kg / mm 2 20kg / mm 2 25kg / mm 2 30kg / mm 2 35kg / mm 2 40kg / mm 2 45kg / mm 2 50kg / mm 2 55kg / mm 2 60kg / mm 2 65kg / mm 2 70kg / mm 2 75kg / mm 2 80kg / mm 2 85kg / mm 2 90kg / mm 2 95kg / mm 2 100kg / mm 2 , or a range consisting of any of the above values.

[0085] By limiting the compressive strength of the adhesive film to the above range, the deformation of the adhesive film during the expansion of the battery cell can be reduced, which is beneficial for the adhesive film to provide a higher clamping force to the electrode assembly, thereby reducing the expansion of the battery cell and improving the cycle performance of the battery cell.

[0086] In some embodiments, the water absorption rate of the film at 25°C for 24 hours is less than or equal to 0.1%.

[0087] By limiting the water absorption rate of the adhesive film to the above range, the penetration of water vapor into the contact electrode assembly can be reduced, thereby reducing the side reactions between the material and water in the electrode assembly, improving the stability of the material, and thus improving the cycle performance of the battery cell.

[0088] In some embodiments, the material of the film may include one or more of epoxy resin, polypropylene, polyacrylate, epoxy acrylate, polyurethane acrylate, and polystyrene.

[0089] In some embodiments, the battery cell provided in this application can be prepared by the following steps:

[0090] S10 provides an electrode assembly, which includes a positive electrode, a negative electrode, and a solid electrolyte membrane, with the solid electrolyte membrane located between the positive and negative electrode; the electrode assembly includes a main body and a tab extending from the main body.

[0091] S20, Immerse the electrode assembly in the adhesive to coat the surface of the main body to form an adhesive coating layer;

[0092] S30, the adhesive coating layer is cured to form an adhesive film covering the main body.

[0093] The preparation method provided in this application involves immersing the main body of the electrode assembly in adhesive. After the adhesive cures, a film is formed on the surface of the main body. This film can provide high fastening force for the electrode assembly, thereby suppressing the cyclic expansion of the battery cell during charging and discharging, and thus improving the cycle performance of the battery cell.

[0094] In some embodiments, step S30 can be performed in a glue-applying device. Specifically, referring to FIG4, the glue-applying device 8 includes a sleeve 81 with one open end, which is used to accommodate the electrode assembly 71. A glue-applying groove 82 is provided at the open end of the sleeve 81, and a glue-applying port communicating with the inside of the sleeve 81 is provided on the glue-applying groove 82. When applying glue to the electrode assembly 71, glue can be injected into the glue-applying groove 82 first, and the glue in the glue-applying groove 82 is injected into the inside of the sleeve 81 through the glue-applying port to cover the surface of the electrode assembly 71.

[0095] In some embodiments, referring to FIG5, the glue injection device further includes a base plate 83 for supporting the electrode assembly 71. The base plate 83 is located inside the adhesive sleeve 81. A glue guiding hole 831 is formed through the base plate 83 along the thickness direction. Multiple glue guiding holes 831 can be provided, and the multiple glue guiding holes 831 can be spaced apart. A glue guiding groove 832 is formed on the base plate 83 along the length or width direction. The glue guiding groove 832 communicates with the glue guiding hole 831. The arrangement of the glue guiding groove 832 and the glue guiding hole 831 facilitates the glue to flow fully in the height direction and wet the electrode assembly 71. During glue injection, the electrode assembly 71 is supported by the base plate 83. The glue can flow through the glue guiding groove 832 and the glue guiding hole 831 on the base plate 83 to wet the bottom of the electrode assembly 71, thereby achieving glue coating on the bottom of the electrode assembly 71 to form a glue film.

[0096] Figure 6 shows a schematic diagram of an electrode assembly with a surface coated with an adhesive film in some embodiments of this application.

[0097] In some embodiments, the adhesive may include one or more of epoxy resin, polypropylene, polyacrylate, epoxy acrylate, polyurethane acrylate, and polystyrene.

[0098] Limiting the types of adhesives to the above range is beneficial for forming an adhesive film with high strength and hardness to provide a higher fastening force to the electrode assembly, thereby reducing the cyclic expansion of the battery cells during charging and discharging and improving the cycle performance of the battery cells.

[0099] In some embodiments, the viscosity of the adhesive can be from 30 cps to 10,000 cps. Exemplarily, the viscosity of the adhesive can be 30 cps, 50 cps, 80 cps, 100 cps, 500 cps, 800 cps, 1000 cps, 2000 cps, 3000 cps, 4000 cps, 5000 cps, 6000 cps, 7000 cps, 8000 cps, 9000 cps, 10000 cps, or any range of the above values. Optionally, the viscosity of the adhesive can be from 80 cps to 5000 cps.

[0100] Limiting the viscosity of the adhesive within the aforementioned range allows for good fluidity, facilitating its wetting and coating of the electrode assembly's main body surface. Higher viscosity results in poorer fluidity, making it difficult to form a uniform and dense film; conversely, lower viscosity leads to poorer adhesion to the electrode assembly surface, hindering its coating.

[0101] In some embodiments, after forming an adhesive coating layer on the surface of the electrode assembly by injection, the adhesive coating layer is cured to form an adhesive film.

[0102] In some embodiments, the curing process may include one or more of water bath heat curing, infrared curing, ultraviolet curing, and green light curing.

[0103] In some embodiments, the curing temperature can be from 50°C to 500°C. Exemplarily, the curing temperature can be 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, or any range of the above values.

[0104] In some embodiments, the curing time can be from 5 min to 30 min. For example, the curing time can be 5 min, 8 min, 10 min, 12 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min, or any range of the above values.

[0105] In some embodiments, step S10 may further include: performing isostatic pressing on the electrode assembly.

[0106] In this application, isostatic pressing is a well-known concept in the art. It utilizes Pascal's principle to fill a high-pressure cylinder with a pressure-transmitting medium. Taking advantage of the incompressibility and uniform pressure transmission properties of the medium (liquid or gas), the electrode assembly is uniformly pressurized from all directions, resulting in a high-density and highly uniform electrode assembly. Since solid-state batteries are assembled by stacking positive electrode plates, solid electrolytes, and negative electrode plates, the solid electrolyte and the positive and negative electrode plates are in solid-solid contact. Isostatic pressing can create a good solid-solid contact interface between the solid electrolyte and the positive and negative electrode plates, which helps to further reduce the internal voids of the battery cell, improve the contact effect between the internal interfaces of the battery cell, enhance conductivity, and thus improve the energy density and cycle performance of the battery cell.

[0107] Specifically, the electrode assembly can be placed in a sealed high-pressure container, and at a preset temperature and pressure, the electrode assembly is uniformly squeezed from all sides using a pressure-transmitting medium, which can further improve the density of the electrode assembly and thus provide higher energy density to meet the needs of solid-state batteries.

[0108] In some embodiments, the isostatic pressing temperature can be from 25°C to 300°C. Exemplarily, the isostatic pressing temperature can be 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, 280°C, 300°C, or any range of the above values.

[0109] In some embodiments, the pressure for isostatic pressing can be from 100 MPa to 3000 MPa. Exemplarily, the pressure for isostatic pressing can be 100 MPa, 200 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1000 MPa, 1200 MPa, 1500 MPa, 1800 MPa, 2000 MPa, 2200 MPa, 2500 MPa, 2800 MPa, 3000 MPa, or any range of the above values.

[0110] In some embodiments, the isostatic pressing time can be from 5 min to 30 min. Exemplarily, the isostatic pressing time can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 3 min, 14 min, 1 min, 16 min, 17 min, 18 min, 1 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, or any range of the above values.

[0111] In some embodiments, the pressure transmission medium in the isostatic pressing process may include any one of water, ester, or inert gas.

[0112] [Positive electrode plate]

[0113] In some embodiments, the positive electrode includes a positive current collector and a positive film layer located on at least one surface of the positive current collector.

[0114] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0115] In some embodiments, the positive electrode film layer includes a positive electrode active material.

[0116] In some embodiments, the positive electrode active material includes one or more of lithium phosphate, layered lithium transition metal oxide, Prussian blue compounds, polyanionic compounds, and sodium transition metal oxide.

[0117] If the positive electrode active material is one or more of lithium phosphate and layered lithium transition metal oxide, then the positive electrode active material can be used in lithium-ion battery cells; if the positive electrode active material is one or more of Prussian blue compounds, polyanionic compounds, and sodium transition metal oxide, then the positive electrode material can be used in sodium-ion battery cells.

[0118] Lithium-containing phosphates may include one or more of lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, and their respective modified compounds.

[0119] Examples of layered lithium-containing transition metal oxides may include one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds.

[0120] In some embodiments, the layered lithium-containing transition metal oxide may include Ni. The molar amount of Ni may account for more than 70% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; optionally, the molar amount of Ni may account for more than 80% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide; more preferably, the molar amount of Ni may account for more than 90% of the total molar amount of transition metal elements in the layered lithium-containing transition metal oxide.

[0121] The higher the Ni content in layered lithium-containing transition metal oxides, the higher the energy density of the battery cell.

[0122] In some embodiments, layered lithium-containing transition metal oxides may include Li a Ni b Co c M d O e A f Wherein, 0 < a ≤ 1.2; 0.8 ≤ b < 1; 0 < c < 1; 0 < d < 1; 1 ≤ e ≤ 2; 0 ≤ f ≤ 1; M includes, but is not limited to, one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B; A includes, but is not limited to, one or more of N, F, S, and Cl. This can further improve the energy density of individual battery cells.

[0123] In some embodiments, as an example, layered lithium-containing transition metal oxides may include, but are not limited to, LiNi. 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.9 Co 0.06 Mn 0.04 O2, LiNi 0.92 Co 0.06 Mn 0.02 O2, LiNi 0.96 Co 0.02 Mn 0.02 One or more of O2.

[0124] During the charging and discharging process of a battery cell, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. After charge-discharge cycles, the molar Li content may change when the positive electrode active material is applied to the battery cell.

[0125] In some embodiments, as an example, sodium transition metal oxides may include, but are not limited to:

[0126] Na 1-x Cu h Fe k Mn l M 1 m O 2-γ M 1 It is one or more of Li, Be, B, Mg, Al, K, Ca, Ti, Co, Ni, Zn, Ga, Sr, Y, Nb, Mo, In, Sn and Ba, 0 < x ≤ 0.33, 0 < h ≤ 0.24, 0 ≤ k ≤ 0.32, 0 < l ≤ 0.68, 0 ≤ m < 0.1, h + k + l + m = 1, 0 ≤ y < 0.2;

[0127] Na 0.67 Mn 0.7 Ni z M 2 0.3-z O2, where M 2 It is one or more of Li, Mg, Al, Ca, Ti, Fe, Cu, Zn and Ba, where 0 < z ≤ 0.1;

[0128] Na a Li b Ni c Mn d Fe e O2, where 0.67 < a ≤ 1, 0 < b < 0.2, 0 < c < 0.3, 0.67 < d + e < 0.8, and b + c + d + e = 1.

[0129] In some embodiments, as an example, the polyanionic compound may include, but is not limited to:

[0130] A 1 f M 3 g (PO4) i O j X 1 3-jWhere A is one or more of H, Li, Na, K, and NH4, and M 3 It is one or more of Ti, Cr, Mn, Fe, Co, Ni, V, Cu and Zn, X 1 It is one or more of F, Cl and Br, 0 < f ≤ 4, 0 < g ≤ 2, 1 ≤ i ≤ 3, 0 ≤ j ≤ 2;

[0131] Na n M 4 PO4X 2 M 4 It is one or more of Mn, Fe, Co, Ni, Cu and Zn, X 2 It is one or more of F, Cl and Br, where 0 < n ≤ 2;

[0132] Na p M 5 q (SO4)3, where M 5 It is one or more of Mn, Fe, Co, Ni, Cu and Zn, 0 < p ≤ 2, 0 < q ≤ 2;

[0133] Na s Mn t Fe 3-t (PO4)2(P2O7), where 0<s≤4, 0≤t≤3, for example, t is 0, 1, 1.5, 2 or 3.

[0134] In some embodiments, as an example, Prussian blue compounds may include, but are not limited to:

[0135] A u M 6 v [M 7 (CN)6] w ·xH2O, where A is H + NH4 + M is one or more of alkali metal cations and alkaline earth metal cations. 6 and M 7 Each is independently one or more transition metal cations, 0 < u ≤ 2, 0 < v ≤ 1, 0 < w ≤ 1, 0 < x < 6. For example, A is H. + Li + Na + K + NH4 + 、Rb + Cs + 、Fr + Be 2+ Mg 2+ Ca 2+ 、Sr2+ Ba 2+ and Ra 2+ One or more of them, M 6 and M 7 Each is an independently selected cation of one or more transition metal elements chosen from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, and W. Optionally, A is Li. + Na + and K + One or more of them, M 6 It is a cation of one or more transition metal elements selected from Mn, Fe, Co, Ni, and Cu, M 7 It is a cation of one or more transition metal elements selected from Mn, Fe, Co, Ni and Cu.

[0136] In the examples of positive electrode active materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of O to change, and the actual molar content of O will fluctuate.

[0137] The modified compounds for the above-mentioned positive electrode active materials can be obtained by doping and / or surface coating of the positive electrode active materials.

[0138] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0139] In some implementations, the weight percentage of the binder in the positive electrode film layer is greater than or equal to 0.5%, which is beneficial for obtaining good adhesion performance.

[0140] In some embodiments, the positive electrode film layer further includes a conductive agent. As an example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0141] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be made by forming a metal material, such as aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, on the polymer substrate. The polymer substrate may include polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), and other substrates.

[0142] In some embodiments, the thickness of the positive current collector is from 4 μm to 20 μm. It is optionally from 6 μm to 18 μm, and more preferably from 8 μm to 16 μm.

[0143] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0144] [Negative electrode plate]

[0145] In some embodiments, the negative electrode film layer comprises a negative electrode active material.

[0146] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector. The negative electrode current collector can be made of materials such as metal foil, carbon-coated metal foil, or porous metal plate, and copper foil is an option.

[0147] As an example, the negative electrode active material may include one or more of the following: artificial graphite, natural graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon, and silicon-carbon composites.

[0148] Silicon-based composite materials can be prepared by methods known in the art. For example, they can be prepared by vapor deposition using graphite and silicon materials as raw materials.

[0149] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0150] In some embodiments, the negative electrode film layer may further include a negative electrode binder. As an example, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0151] In some embodiments, the negative electrode film layer may also include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, etc.

[0152] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. Examples of metal foils include copper foil, copper alloy foil, aluminum foil, and aluminum alloy foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one side of the polymeric material substrate. Examples of metal materials include, but are not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Examples of polymeric material substrates include, but are not limited to, one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0153] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet may also include a conductive undercoat layer sandwiched between the negative electrode current collector and the negative electrode film layer and located on the surface of the negative electrode current collector, which may be composed of a conductive agent and a binder; in some embodiments, the negative electrode sheet may also include a protective layer covering the surface of the negative electrode film layer.

[0154] The negative electrode sheet can be prepared as follows: The negative electrode active material, negative electrode binder, negative electrode conductive agent, and optional other additives are dispersed in a solvent and stirred evenly to form a negative electrode slurry; the negative electrode slurry is coated onto a negative electrode current collector, and after drying, rolling, and other processes, a negative electrode sheet is formed. The solvent can be N-methylpyrrolidone (NMP) or deionized water, but is not limited to these.

[0155] [Solid electrolyte]

[0156] Solid electrolyte membranes include solid electrolytes, which may include one or more of the following: sulfide solid electrolytes, oxide solid electrolytes, and organic solid electrolytes.

[0157] Sulfide solid electrolytes have high 10 -2 S / cm to 10 -3 A lithium-ion conductivity of S / cm facilitates the formation of contact interfaces between electrodes and exhibits high mechanical strength and flexibility. In this application embodiment, there are no particular limitations on the type of sulfide-based solid electrolyte, and all known sulfide materials used in the battery field are acceptable. In this application embodiment, the sulfide-based solid electrolyte may include Li6PS5Cl (LPSCl), Thio-LISICON (Li 3.25 Ge 0.25 P 0.75S4), Li2S-P2S5-LiCl, Li2S-SiS2, Lil-Li2S-SiS2, Lil-Li2S-P2S5, Lil-Li2S-P2O5, Lil-Li3PO4-P2S5, Li2S-P2S5, Li3PS4, Li7P3S 11 , Lil-Li2S-B2S3, Li3PO4-Li2S-Si2S, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, Li 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 and Li7P3S 11 One or more of them.

[0158] Oxide-based solid electrolytes exhibit high safety in air and have a 10 -3 S / cm to 10 -4 The lithium-ion conductivity (S / cm) is lower than that of sulfide-based solid electrolytes, but relatively higher. Furthermore, oxide-based solid electrolytes exhibit high electrochemical safety and mechanical strength. However, oxide-based solid electrolytes have high oxidation voltage. Additionally, solid electrolytes have high grain boundary resistance, making it difficult to form a contact interface between the electrode and electrolyte, requiring high-temperature heat treatment processes of 1000°C or higher, and these processes are difficult to scale up. In the embodiments of this application, the oxide-based solid electrolyte can be any known oxide material used in the field of lithium batteries. In the embodiments of this application, the oxide-based solid electrolyte includes perovskite solid electrolyte, sodium superionic conductor solid electrolyte (NASICON), lithium superionic conductor solid electrolyte (LISICON), and lithium lanthanum zirconium oxide solid electrolyte (LLZO).

[0159] Organic solid electrolytes (OSEs) are a type of solid electrolyte. OSEs can readily form electrode interfaces and minimize dendrite growth, thus ensuring stable reactions between OSEs and lithium metal. The disadvantages of OSEs are their relatively low lithium-ion conductivity and the fact that they typically require high-temperature operation. In this embodiment, the OSE comprises polyethylene oxide (PEO).

[0160] The thickness of the solid electrolyte membrane can be selected differently depending on the properties of the desired all-solid-state battery. Specifically, in some embodiments, the thickness of the solid electrolyte membrane can be from 0.1 μm to 1000 μm; in other embodiments, the thickness of the solid electrolyte membrane can be from 1 μm to 500 μm; in still other embodiments, the thickness of the solid electrolyte membrane can be from 20 μm to 30 μm; this application does not limit it in this regard.

[0161] For ease of subsequent description and understanding, the preparation method of the battery cell and the battery cell in the embodiments of this application can use sulfide-based solid electrolytes.

[0162] Example

[0163] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0164] Example 1

[0165] Positive electrode sheet

[0166] Under an argon atmosphere, the positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), binder polyvinylidene fluoride (PVDF), and conductive agent carbon fiber are dispersed in xylene solvent at a mass ratio of 98:1:1, with the solid content controlled at 60%. After stirring evenly, the mixture is coated onto the positive current collector aluminum foil and dried to obtain the positive electrode sheet.

[0167] Negative electrode sheet

[0168] Silicon carbide, conductive carbon, and binder polyvinylidene fluoride (PVDF) are mixed and dispersed in solvent pseudotrimethylbenzene at a mass ratio of 90:7:3, with the solid content controlled at 55%. The mixture is stirred evenly to obtain a negative electrode slurry. The negative electrode slurry is then evenly coated onto the surface of the negative electrode current collector copper foil and dried to obtain a negative electrode sheet.

[0169] Solid electrolyte membrane

[0170] In an argon atmosphere, the sulfide solid electrolyte Li6PS5Cl and the binder nitrile rubber (NBR) are dispersed in p-xylene (solid content is 50%) at a mass ratio of 99:1. After stirring evenly, the mixture is coated onto a PET film and dried to obtain an electrolyte membrane.

[0171] Solid-state battery cells

[0172] The electrolyte membrane is covered on the surface of the positive electrode, and the electrolyte membrane is transferred to the positive electrode by cold pressing at 10MPa. The PET film is removed to obtain a positive / solid electrolyte membrane composite electrode. Then, the negative electrode is attached to the other side of the solid electrolyte membrane and assembled to obtain an electrode assembly.

[0173] The electrode assembly was subjected to isostatic pressing at a temperature of 200℃, a pressure of 200 MPa, and a time of 20 min, with helium as the pressure transmission medium.

[0174] The isostatically pressed electrode assembly is placed in a rubber sleeve, the bottom plate supports the electrode assembly, and epoxy resin (viscosity 100cps) is injected. The epoxy resin completely wets the main body of the electrode assembly and forms a uniform film layer on the outside of the main body.

[0175] The adhesive film was cured by infrared heating at 100℃ for 20 minutes. Then the adhesive sleeve was removed to obtain an electrode assembly with an outer adhesive film covering the film. The thickness of the adhesive film was 200μm. The electrode assembly was then encapsulated to obtain a solid-state battery cell.

[0176] Examples 2-6

[0177] The preparation method of solid-state battery cells is similar to that in Example 1, except that the parameters of the film are different. For details of parameter adjustments, please refer to Table 1.

[0178] Comparative Example 1

[0179] Positive electrode sheet

[0180] Under an argon atmosphere, the positive electrode active material LiNi0.8Co0.1Mn0.1O2 (NCM811), the binder polyvinylidene fluoride (PVDF), and the conductive agent carbon fiber are dispersed in the solvent p-xylene at a mass ratio of 98:1:1, with the solid content controlled at 60%. After stirring evenly, the mixture is coated onto the positive electrode current collector aluminum foil and dried to obtain the positive electrode sheet.

[0181] Negative electrode sheet

[0182] In an argon atmosphere, silicon powder, the negative electrode active material, and polyvinylidene fluoride (PVDF), the binder, are dispersed in xylene (solid content 50%) at a weight ratio of 97:3. After stirring evenly, the mixture is coated onto copper foil, the negative electrode current collector, and dried to obtain the negative electrode sheet.

[0183] Solid electrolyte membrane

[0184] In an argon atmosphere, the sulfide solid electrolyte Li6PS5Cl and the binder nitrile rubber (NBR) are dispersed in p-xylene (solid content is 50%) at a mass ratio of 99:1. After stirring evenly, the mixture is coated onto a PET film and dried to obtain an electrolyte membrane.

[0185] Solid-state battery cells

[0186] The electrolyte membrane is covered on the surface of the positive electrode, and the electrolyte membrane is transferred to the positive electrode by cold pressing at 10MPa. The PET film is removed to obtain a positive / solid electrolyte membrane composite electrode. Then, the negative electrode is attached to the other side of the solid electrolyte membrane and assembled to obtain an electrode assembly.

[0187] The electrode assembly is subjected to isostatic pressing at a temperature of 200℃, a pressure of 200 MPa, and a time of 20 min, with helium as the pressure transmission medium. The isostatically pressed electrode assembly is then encapsulated to obtain a solid-state battery cell.

[0188] Test section

[0189] 1. Elastic modulus of the adhesive film

[0190] At an ambient temperature of 25℃ and a humidity of 80% RH, the changes in thickness and pressure during the compression process of the battery cell were monitored simultaneously using an in-situ compression test platform to obtain the stress-strain curve. The slope corresponding to a pressure of 2000 kg is the corresponding modulus.

[0191] 2. Film hardness

[0192] The hardness tester is held perpendicular to the sample surface, and the probe of the hardness tester is pressed down. The probe causes a slight deformation of the sample surface, and the hardness value in units of HD is obtained by reading the value.

[0193] 3. Compressive strength of the adhesive film

[0194] The peelable film has a size of 100mm*25mm*3mm. An in-situ compression test platform was used to apply a pressure of 2000kg. The changes in film thickness and pressure were recorded to obtain the stress-strain curve, thereby obtaining the compressive strength value.

[0195] 4. Water absorption rate of the film

[0196] Place the sample in an oven at 110℃±5℃ and dry it to constant weight with a weighing accuracy of 0.001g. Place the sample in a vacuum environment with a vacuum degree ≤-95Kpa and inject distilled water into the vacuum container. The sample should not come into contact with the distilled water. After 24 hours, weigh the sample. The ratio of the weight difference before and after to the initial weight is the water absorption rate.

[0197] 5. Cyclic expansion rate of individual battery cells

[0198] The initial thickness of the electrode assembly will be measured at 25℃ and recorded as H0. The battery cell will be charged at a constant current of 0.1C to 4.3V, then charged at a constant voltage of 0.05C, left to stand for 5 minutes, and then discharged at a constant current of 0.1C to 2.8V. The above charge and discharge process will be repeated for 900 cycles. The battery cell will be disassembled to obtain the electrode assembly, and the thickness of the electrode assembly will be measured again and recorded as H1. The cycle expansion rate of the battery cell (%) is then calculated as (H1-H0) / H0×100%.

[0199] 6. Number of battery cell cycles

[0200] At 25°C, the battery cell was charged to 4.3V at a constant current of 0.1C, then charged to 0.05C at a constant voltage. After standing for 5 minutes, it was discharged to 2.8V at a constant current of 0.1C. The initial discharge capacity C0 was recorded. The above charge and discharge process was repeated, and the discharge capacity Cn of each cycle was recorded until the cycle capacity retention rate (Cn / C0*100%) was below 80%. The number of cycles was recorded.

[0201] For detailed performance test results, please refer to Table 1.

[0202] Table 1

[0203] Based on the data in Table 1, in this embodiment of the application, coating the electrode assembly with an adhesive film can effectively reduce the expansion of the battery cells and improve their cycle performance.

[0204] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solid-state battery cell, comprising an electrode assembly, the electrode assembly including a main body and tabs extending from the main body, the main body including a positive electrode, a negative electrode, and a solid electrolyte membrane stacked together, the solid electrolyte membrane being located between the positive and negative electrode, the main body being covered with an adhesive film, the adhesive film having an elastic modulus of 1000 N / mm². 2 -10000N / mm 2 .

2. The solid-state battery cell according to claim 1, wherein, The thickness of the adhesive film is 80 μm to 1000 μm.

3. The solid-state battery cell according to claim 1 or 2, wherein, The adhesive film is made of one or more of the following materials: epoxy resin, polypropylene, polyacrylate, epoxy acrylate, polyurethane acrylate, and polystyrene.

4. The solid-state battery cell according to any one of claims 1 to 3, wherein, The adhesive film satisfies at least one of the following conditions: (1) The Shore hardness of the adhesive film is 50HD to 200HD; (2) The compressive strength of the adhesive film is 5 kg / mm². 2 Up to 100kg / mm 2 ; (3) The water absorption rate of the film at 25°C for 24 hours is less than or equal to 0.1%.

5. The solid-state battery cell according to any one of claims 1 to 4, wherein, The solid-state battery cell has an expansion rate of 0.3%-5% after 900 charge-discharge cycles.

6. A method for preparing a solid-state battery cell, comprising the following steps: An electrode assembly is provided, the electrode assembly including a positive electrode, a negative electrode, and a solid electrolyte membrane, the solid electrolyte membrane being located between the positive electrode and the negative electrode; the electrode assembly includes a main body and a tab extending from the main body; The electrode assembly is immersed in adhesive to coat the surface of the main body to form an adhesive coating layer; The adhesive coating layer is cured to form an adhesive film covering the main body.

7. The preparation method according to claim 6, wherein, The adhesive includes one or more of epoxy resin, polypropylene, polyacrylate, epoxy acrylate, polyurethane acrylate, and polystyrene.

8. The preparation method according to claim 6 or 7, wherein, The viscosity of the adhesive is between 30 cps and 10,000 cps.

9. The preparation method according to claim 8, wherein, The viscosity of the adhesive is between 80 cps and 5000 cps.

10. The preparation method according to any one of claims 6 to 9, wherein, The curing process satisfies at least one of the following conditions: (1) The curing temperature is 50°C to 500°C; (2) The curing time is 5 min to 30 min; (3) The curing process includes one or more of water bath heat curing, infrared curing, ultraviolet curing, and green light curing.

11. The preparation method according to any one of claims 6 to 10, wherein, The provision of the electrode assembly includes performing an isostatic pressing process on the electrode assembly, wherein the isostatic pressing process satisfies at least one of the following conditions: (1) The temperature of the isostatic pressing treatment is 25°C to 300°C; (2) The pressure of the isostatic pressing treatment is 100MPa to 3000MPa; (3) The isostatic pressing treatment time is 5 min to 30 min; (4) The pressure transmission medium in the isostatic pressure treatment process includes any one of water, ester, and inert gas.

12. A battery device comprising a solid-state battery cell according to any one of claims 1 to 5 or a solid-state battery cell obtained by the preparation method according to any one of claims 6 to 11.

13. An electrical device comprising a solid-state battery cell according to any one of claims 1 to 5, a solid-state battery cell obtained by the preparation method according to any one of claims 6 to 11, or a battery device according to claim 12.

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