Electrode assembly, battery monomer, preparation method, battery device and power utilization device

Abstract

The invention provides an electrode assembly, a battery monomer, a preparation method, a battery device and a power utilization device, the preparation method of the battery monomer comprises the following steps: providing a to-be-pressed electrode assembly, at least one side of the to-be-pressed electrode assembly along the thickness direction of the to-be-pressed electrode assembly being an outermost active material layer; bonding a bonding layer on the outermost active material layer to form a middle assembly; pressing the intermediate assembly to obtain a pressed assembly, wherein the density of the pressed assembly meets the first preset density; removing the bonding layer and the outermost active material layer of the pressed assembly to form an electrode assembly; and assembling the electrode assembly into the shell to prepare the battery monomer. The energy density of the single battery can be improved.

Description

Technical Field

[0001] This application relates to the field of battery devices, specifically to an electrode assembly, a battery cell, a preparation method, a battery device, and an electrical device. Background Technology

[0002] Battery cells have characteristics such as high capacity and long lifespan, and are therefore widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] As battery cells are used more and more widely, the requirements for battery performance are also gradually increasing, such as the requirements for the energy density of battery cells. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide an electrode assembly, a battery cell, a preparation method, a battery device, and an electrical device that can improve the energy density of the battery cell.

[0005] In a first aspect, this application proposes a method for preparing a battery cell. The method includes: providing an electrode assembly to be pressed, wherein at least one side of the electrode assembly along its own thickness direction is an outermost active material layer; bonding an adhesive layer onto the outermost active material layer to form an intermediate assembly; pressing the intermediate assembly to obtain a pressed assembly, wherein the density of the pressed assembly satisfies a first preset density; removing the adhesive layer and the outermost active material layer of the pressed assembly to form an electrode assembly; and assembling the electrode assembly into a housing to prepare a battery cell.

[0006] Therefore, by removing the outermost ineffective active material layer of the electrode assembly to be charged, the embodiment of this application can increase the space occupied by the active material layer that can participate in charging and discharging, thereby increasing the energy density of the battery cell.

[0007] In some embodiments, the step of pressing the intermediate component to obtain a pressed component, wherein the density of the pressed component satisfies a first preset density, includes: pre-pressing the intermediate component until the density of the intermediate component satisfies a second preset density; and then pressing the intermediate component again to obtain a pressed component, wherein the density of the pressed component satisfies the first preset density, and the first preset density is greater than the second preset density.

[0008] Therefore, by performing multiple pressing processes, the density of the electrode assembly can be improved, which in turn can increase the energy density of the battery cell.

[0009] In some embodiments, the second preset density is 60% to 85%. Thus, the pre-compression treatment results in a higher density, which can improve the density of the electrode assembly and increase the energy density of the battery cell.

[0010] In some embodiments, the step of pre-compressing the intermediate component until the density of the intermediate component meets a second preset density includes: flat-compressing the intermediate component to make the density of the intermediate component meet the second preset density.

[0011] In some embodiments, the pressing temperature is between 25°C and 200°C. Pressing under these conditions effectively improves the density of the electrode assembly and increases the energy density of the individual battery cells.

[0012] In some embodiments, the pressing pressure is between 3 MPa and 20 MPa. Pressing under these conditions effectively improves the density of the electrode assembly and increases the energy density of the individual battery cells.

[0013] In some embodiments, the pressing process takes 10 to 180 seconds. Pressing under these conditions effectively improves the density of the electrode assembly and increases the energy density of the individual battery cells.

[0014] In some embodiments, the first preset density is greater than or equal to 94.0% and less than 100%, and can be selected as 94.0% to 97.5%. Thus, the density after lamination is high, which can improve the density of the electrode assembly and increase the energy density of the battery cell.

[0015] In some embodiments, the step of re-pressing the intermediate component to obtain the pressed component, wherein the density of the pressed component satisfies a first preset density, includes: isostatic pressing the intermediate component to obtain the pressed component, wherein the density of the pressed component satisfies the first preset density.

[0016] In some embodiments, the step of isostatically pressing an intermediate component to obtain a pressed component, wherein the density of the pressed component meets a first preset density, includes providing an encapsulation film to the intermediate component to encapsulate the intermediate component and form a component to be statically pressed; extracting gas from the component to be statically pressed until the vacuum degree inside the component to be statically pressed meets a preset vacuum degree; sealing the component to be statically pressed and then performing isostatic pressing on the component to be statically pressed to obtain a pressed component, wherein the density of the pressed component meets the first preset density; and removing the encapsulation film from the pressed component.

[0017] In some embodiments, the tensile strength of the encapsulation film is between 20 N and 85 N. When the tensile strength of the encapsulation film is within this range, after sealing, some space may remain inside the assembly to be isostatically pressed, providing gas storage space for the gas extruded during isostatic pressing, which is beneficial for further improving density.

[0018] In some embodiments, the encapsulation membrane is made of one or more of the following materials: polyolefin, polyimide, metal, and polyphenylene sulfide. These materials can effectively seal the component to be subjected to static pressure.

[0019] In some implementations, the polyolefin material includes one or more of polyethylene, polypropylene, and polytetrafluoroethylene.

[0020] In some embodiments, the polyimide material includes one or more of polyimide, polyimide ether ketone, polyetherimide, and polyimide ether sulfone.

[0021] In some implementations, the metal material includes one or more of aluminum, copper, and steel.

[0022] In some implementations, the preset vacuum level is -100 kPa to -50 kPa. Applying these conditions to the pressing process effectively improves the density of the electrode assembly and increases the energy density of the individual battery cells.

[0023] In some embodiments, the isostatic pressing temperature is between 0°C and 250°C; pressing under the above conditions can effectively improve the density of the electrode assembly and increase the energy density of the battery cell.

[0024] In some embodiments, the isostatic pressing pressure is between 100 MPa and 2000 MPa; pressing under the above conditions can effectively improve the density of the electrode assembly and increase the energy density of the battery cell.

[0025] In some embodiments, the isostatic pressing process takes 1 to 90 minutes. Applying the pressing process under these conditions effectively improves the density of the electrode assembly and increases the energy density of the individual battery cells.

[0026] In some embodiments, the peel strength of the adhesive layer is from 1 N / m to 80 N / m; the adhesive layer is a film layer with a certain viscosity, thereby enabling the adhesive layer to bond with the outermost active material layer.

[0027] In some embodiments, the shrinkage rate of the adhesive layer is between 2.4% and 11.5%. When the shrinkage rate of the adhesive layer is within the above range, its shrinkage capacity is relatively strong, and the shrinkage amplitude during the pressing process is relatively large, which is more conducive to the peeling off of the outermost active material layer.

[0028] In some embodiments, the adhesive layer includes one or more of the following: polyolefin materials, polyimide materials, polyether materials, polylactic acid, polyacrylate, polyurethane, and ethylene-vinyl acetate copolymer.

[0029] In some embodiments, the polyolefin material includes one or more of polyethylene, polypropylene, and polytetrafluoroethylene; the above materials can effectively bond the outermost active material layer.

[0030] In some embodiments, the polyimide material includes one or more of polyimide, polyimide ether ketone, polyetherimide, and polyimide ether sulfone.

[0031] In some embodiments, the polyether material includes one or more of polyvinyl ether and polyphenylene sulfide.

[0032] In some embodiments, the step of providing a pressure-bearing electrode assembly, wherein at least one side of the pressure-bearing electrode assembly along its own thickness direction is the outermost active material layer, includes providing a plurality of first electrodes, each first electrode including a first current collector and a first active material layer, the first active material layer being disposed on both sides of the first current collector along the thickness direction; providing a plurality of second electrodes, each second electrode including a second current collector and a second active material layer, the second active material layer being disposed on both sides of the second current collector along the thickness direction, the second electrodes and the first electrodes having opposite polarities; providing a plurality of solid electrolyte layers; and alternately stacking the first electrodes, solid electrolyte layers and second electrodes along the thickness direction to obtain the pressure-bearing electrode assembly, wherein the first electrodes are located at the outermost side of the pressure-bearing electrode assembly along the thickness direction, and the outermost active material layer is the first active material layer; or the second electrodes are located at the outermost side of the pressure-bearing electrode assembly along the thickness direction, and the outermost active material layer is the second active material layer.

[0033] In some implementations, the projection surface of the first current collector along the thickness direction has a rectangular outline. This allows for a further increase in the energy density of the battery cell.

[0034] In some embodiments, the projection surface of the second current collector along the thickness direction has a rectangular outline. This allows for a further increase in the energy density of the battery cell.

[0035] In some embodiments, the outermost active material layer includes a positive electrode active material; or the outermost active material layer includes a negative electrode active material.

[0036] In some embodiments, the electrode assembly to be pressed has outermost active material layers on both sides along the thickness direction.

[0037] Secondly, this application proposes a battery cell, which includes an electrode assembly. The electrode assembly includes a solid electrolyte layer and multiple electrode plates. The multiple electrode plates are stacked along the thickness direction of the electrode assembly. The solid electrolyte layer is located between two adjacent electrode plates. Each electrode plate includes a current collector and an active material layer disposed on at least one side of the current collector. The current collector is located on at least one side of the electrode assembly along the thickness direction.

[0038] Therefore, when at least one side of the electrode assembly along the thickness direction is a current collector, neither side of the electrode assembly includes an active material layer that cannot participate in charging and discharging, i.e. an ineffective active material layer. This can increase the space occupied by the active material layer that participates in charging and discharging, and can increase the energy density of the battery cell.

[0039] In some embodiments, both sides of the electrode assembly along the thickness direction are current collectors. Therefore, when both sides of the electrode assembly along the thickness direction are current collectors, the energy density of the individual battery cells can be further improved.

[0040] In some embodiments, the plurality of electrode plates include a plurality of first electrode plates and a plurality of second electrode plates. Each first electrode plate includes a first current collector and a first active material layer, the first active material layer being disposed on at least one side of the first current collector along its thickness direction. Each second electrode plate includes a second current collector and a second active material layer, the second active material layer being disposed on at least one side of the second current collector along its thickness direction. The first and second electrode plates have opposite polarities. The plurality of first and second electrode plates are stacked along their thickness direction, and at least one side of the electrode assembly along its thickness direction is the first current collector; or at least one side of the electrode assembly along its thickness direction is the second current collector. This improves the energy density of the battery cell.

[0041] In some embodiments, the electrode assembly has first current collectors on both sides along the thickness direction; thereby, the energy density of the battery cell can be further improved.

[0042] In some embodiments, the electrode assembly has second current collectors on both sides along its thickness direction. This allows for a further increase in the energy density of the battery cell.

[0043] In some implementations, the projected surface of the current collector along its thickness direction has a rectangular outline. This increases the overall area of ​​the current collector supporting the active material layer, which is beneficial for improving the energy density of the battery cell.

[0044] Thirdly, this application provides a method for preparing an electrode assembly. The method includes: providing an electrode assembly to be pressed, wherein at least one side of the electrode assembly to be pressed along its own thickness direction is an outermost active material layer; bonding an adhesive layer onto the outermost active material layer to form an intermediate assembly; pressing the intermediate assembly to obtain a pressed assembly, wherein the density of the pressed assembly satisfies a first preset density; and removing the adhesive layer and the outermost active material layer of the pressed assembly to form an electrode assembly.

[0045] Fourthly, this application provides an electrode assembly comprising a plurality of electrode sheets and a solid electrolyte layer. The plurality of electrode sheets are stacked along the thickness direction of the electrode assembly, and the solid electrolyte layer is located between two adjacent electrode sheets. Each electrode sheet includes a current collector and an active material layer disposed on at least one side of the current collector, wherein at least one side of the electrode assembly along the thickness direction is the current collector.

[0046] Therefore, when at least one side of the electrode assembly along the thickness direction is a current collector, neither side of the electrode assembly includes an active material layer that cannot participate in charging and discharging, i.e. an ineffective active material layer. This can increase the space occupied by the active material layer that participates in charging and discharging, and can increase the energy density of the battery cell.

[0047] Fifthly, this application proposes a battery device comprising a battery cell as described in any embodiment of the first aspect of this application or a battery cell prepared by a preparation method as described in any embodiment of the second aspect of this application.

[0048] Sixthly, this application proposes an electrical device, including a battery device as described in the fifth aspect of this application. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced 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.

[0050] Figure 1 Structural schematic diagrams of the vehicle provided for some embodiments of this application;

[0051] Figure 2 An exploded view of a battery pack provided for some embodiments of this application;

[0052] Figure 3 Schematic diagram of the structure of a battery module provided for some embodiments of this application

[0053] Figure 4 Schematic diagrams of the structure of a battery cell provided for some embodiments of this application;

[0054] Figure 5 This application provides schematic diagrams of the structure of electrode assemblies in a battery cell for some embodiments.

[0055] Figure 6 Schematic diagrams of the structure of electrode assemblies in a battery cell provided for other embodiments of this application;

[0056] Figure 7A schematic diagram of the structure of the first electrode in a battery cell provided in some other embodiments of this application;

[0057] Figure 8 A schematic flowchart illustrating the preparation method of an electrode assembly provided in other embodiments of this application;

[0058] Figure 9 This is a schematic diagram of the structure of the electrode assembly to be pressed provided in some embodiments of this application;

[0059] Figure 10 This application provides structural schematic diagrams of the electrode assembly to be pressed and the adhesive layer in some embodiments;

[0060] Figure 11 A schematic diagram showing the state of the electrode assembly to be pressed in some embodiments of this application during the pressing process;

[0061] Figure 12 This is a schematic diagram of the structure of the encapsulation film provided in some embodiments of this application;

[0062] Figure 13 A schematic flowchart illustrating the preparation method of a battery cell provided in other embodiments of this application;

[0063] The accompanying drawings may not be drawn to scale.

[0064] The annotations in the attached figures are explained as follows:

[0065] X, thickness direction;

[0066] 1. Vehicle; 2. Battery pack; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 5c. Housing space; 6. Battery module; 7. Battery cell;

[0067] 10. Electrode assembly; 20. Housing;

[0068] 30. First electrode; 31. First current collector; 32. First active material layer;

[0069] 40. Second electrode; 41. Second current collector; 42. Second active material layer;

[0070] 50. Solid electrolyte layer;

[0071] 60. Adhesive layer;

[0072] 70. Encapsulation film; 71. Encapsulation cavity; 72. Encapsulation cover. Detailed Implementation

[0073] The following detailed description discloses embodiments of the electrode assembly, battery cell, preparation method, 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 actually 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.

[0074] 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.

[0075] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0076] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0077] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means 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.

[0078] In this application, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations.

[0079] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0080] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0081] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0082] In this application, "multiple" refers to two or more (including two). In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used.

[0083] In this application, the battery cell may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium lithium-ion battery cells, sodium-ion battery cells, magnesium-ion battery cells, lithium metal battery cells, sodium metal batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited to these shapes either. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these types either.

[0084] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery device mentioned in this application may include a battery module or a battery pack. A battery device generally includes a housing for encapsulating one or more battery cells. The housing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0085] With the development of the battery device field, the performance requirements for individual battery cells are gradually increasing, such as the requirement for increased energy density of individual battery cells.

[0086] The outermost active material layer of the electrode assembly along its own thickness direction does not participate in charging and discharging. The embodiments of this application improve the energy density of the battery cell by removing the outermost active material layer of the electrode assembly, thereby increasing the mass or volume of the active material layer inside the battery cell that can participate in charging and discharging.

[0087] The battery cells described in this application are applicable to battery devices and electrical devices that use battery devices.

[0088] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of this application do not impose special limitations on the above-mentioned electrical devices.

[0089] For ease of explanation, the following implementation method uses a vehicle as an example of an electrical device.

[0090] Figure 1 A schematic diagram of the vehicle structure provided for some embodiments of this application.

[0091] like Figure 1 As shown, a battery pack 2 is installed inside the vehicle 1. The battery pack 2 can be located at the bottom, front, or rear of the vehicle 1. The battery pack 2 can be used to power the vehicle 1; for example, the battery pack 2 can serve as the operating power source for the vehicle 1.

[0092] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery pack 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0093] In some embodiments of this application, the battery pack 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.

[0094] Figure 2 This is an exploded view of a battery pack provided for some embodiments of this application. For example... Figure 2 As shown, the battery pack 2 includes a housing 5 and individual battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0095] 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 open end, 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 open side, 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.

[0096] 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.

[0097] 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.

[0098] In battery pack 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, 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, parallel, or in a mixed configuration and then housed in housing 5. Alternatively, multiple battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed in housing 5.

[0099] A single battery cell can be the smallest unit that makes up a battery device.

[0100] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0101] In some implementations, such as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0102] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two battery cells 7.

[0103] Figure 4 This is a schematic diagram of the structure of a battery cell 7 provided in some embodiments of this application. Figure 5 This is a schematic diagram of the structure of the electrode assembly 10 of the battery cell 7 provided in some embodiments of this application.

[0104] like Figure 4 and Figure 5 As shown, in some embodiments, the battery cell 7 includes an electrode assembly 10 and a housing 20, with the electrode assembly 10 housed within the housing 20.

[0105] The outer casing 20 can be of various shapes, such as a cylinder or a cuboid. The shape of the outer casing 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cylindrical structure, the outer casing 20 can be a cylindrical structure. If the electrode assembly 10 is a cuboid structure, the outer casing 20 can be a cuboid structure.

[0106] The outer casing 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this application embodiment does not impose any special limitations on this. Optionally, the inner wall of the outer casing 20 may also include an insulating layer, which can separate the outer casing 20 from the electrode assembly 10. The material of the insulating layer can be selected from materials commonly used in the art, and is not particularly limited here.

[0107] The electrode assembly 10 housed within the housing 20 may be one or more.

[0108] From the external shape of the electrode assembly 10, the electrode assembly 10 includes an electrode tab portion and a main body portion. The electrode tab portion includes a first electrode tab and a second electrode tab, which have opposite polarities and extend beyond the main body portion. The first electrode tab is the portion of the first electrode sheet that is not coated with an active material layer, and the second electrode tab is the portion of the second electrode sheet that is not coated with an active material layer. The first and second electrode tabs are used to draw current out from the main body portion. The first and second electrodes have opposite polarities; in other words, one of the first and second electrodes is a positive electrode sheet, and the other is a negative electrode sheet.

[0109] The positive and negative electrodes can be drawn from the same end of the main body, or the positive and negative electrodes can be drawn from opposite ends of the main body.

[0110] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 7, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. Optionally, the electrode assembly 10 also includes a separator disposed between the positive and negative electrodes, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0111] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer including a positive active material.

[0112] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0113] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, silver-surfaced aluminum, or stainless steel can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0114] As an example, when the battery cell 7 in this embodiment is a lithium-ion battery, the positive electrode active material may include one or more of the following materials: phosphate, layered transition metal oxide, and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxide and their respective modified compounds, which is beneficial to improving the energy density of the battery cell 7. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material layer of a battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0115] Examples of phosphates may include, but are not limited to, one or more of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0116] Layered transition metal oxides include those with the general formula Li a Ni b Co c M d O e A f One or more of the compounds and their modified compounds. 0.8≤a≤1.2, 0.3≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes one or more of N, F, S and Cl.

[0117] Examples of layered transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 One or more of O2 and its modified compounds.

[0118] When the battery cell 7 in the embodiments of this application is a sodium-ion battery or a sodium metal battery, the positive electrode active material may include, but is not limited to, one or more of sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0119] As an example, positive electrode active materials for sodium-ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In the given condition, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes H. + Li + Na + K + and NH4 + One or more of the following, M' is a transition metal cation, optionally one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0120] In the embodiments of this application, the modified compounds of the above-mentioned positive electrode active materials can be doped and / or surface coated to modify the positive electrode active materials, such as carbon coating modification, fast ion conductor coating modification, etc.

[0121] During the charging and discharging process, the battery cell 7 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the battery cell 7 at different discharge states. In the examples of positive electrode active materials in this application, the molar content of Li refers to the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to the battery system, the molar content of Li may change after charge-discharge cycles.

[0122] In the embodiments of this application, the molar content of oxygen (O) in the positive electrode active materials is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of oxygen (O) to change. In reality, the molar content of oxygen (O) will fluctuate.

[0123] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not have a positive electrode active material layer. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0124] In some embodiments, the positive electrode active material layer may optionally include a positive electrode conductive agent. This application does not impose particular limitations on the type of positive electrode conductive agent. As an example, the positive electrode conductive agent includes one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode active material layer is ≤5 wt%.

[0125] In some embodiments, the positive electrode active material layer may optionally include a positive electrode binder. This application does not impose particular limitations on the type of positive electrode binder. As an example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode active material layer is ≤5 wt%.

[0126] The positive electrode active material layer is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, optional conductive agent, optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0127] In some embodiments, the battery cell is an ion-type battery such as a lithium-ion battery, and the negative electrode can be a negative electrode sheet. The negative electrode sheet can include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. The negative electrode active material layer includes a negative electrode active material.

[0128] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0129] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0130] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 7. As an example, the negative electrode active material may include one or more of the following materials: carbon materials (e.g., carbon materials include one or more of artificial graphite, natural graphite, soft carbon, and hard carbon), silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include one or more of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active material layers in batteries may also be used. These negative electrode active material layers may be used alone or in combination of two or more.

[0131] In some embodiments, the negative electrode active material layer may optionally include a negative electrode conductive agent. This application does not impose particular limitations on the type of negative electrode conductive agent. As an example, the negative electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon fibers. In some embodiments, the mass percentage of the negative electrode conductive agent in the negative electrode active material layer is ≤5 wt%.

[0132] In some embodiments, the negative electrode active material layer may optionally include a negative electrode binder. This application does not impose particular limitations on the type of negative electrode binder. As an example, the negative electrode binder may include one or more of the following: 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). In some embodiments, the mass percentage of the negative electrode binder in the negative electrode active material layer is ≤5 wt%.

[0133] In some embodiments, the negative electrode active material layer may optionally include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of other additives in the negative electrode active material layer is ≤2 wt%.

[0134] In some embodiments, the battery cell 7 also includes an electrolyte. During the charging and discharging process of the battery cell, active ions move back and forth between the positive and negative electrode plates, inserting and extracting. The electrolyte acts as a conductor for the active ions between the positive and negative electrode plates. The embodiments of this application do not impose any particular limitation on the type of electrolyte; it can be selected according to actual needs.

[0135] The electrolyte may include a solid electrolyte, for example, a solid electrolyte disposed in the form of a film between the positive electrode and the negative electrode. For example, the positive electrode, the solid electrolyte layer and the negative electrode are stacked, and the solid electrolyte layer may be coated on the surface of the positive electrode active material layer in the positive electrode, or coated on the surface of the negative electrode active material layer in the negative electrode.

[0136] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, and polymer solid electrolytes.

[0137] Sulfide solid electrolytes include one or more of the following: sulfide crystalline solid electrolytes, sulfide glass, and glass-ceramic solid electrolytes.

[0138] In some embodiments, the sulfide solid electrolyte includes Li 10 GeP2S 12 Li6PS5Cl, Li 10 Sn P2S 12 One or more of Li2S-P2S5, Li2S-SiS2 and Li2S-B2S3.

[0139] Oxide solid electrolytes are classified into two categories according to their material structure: crystalline oxide electrolytes and glassy oxide electrolytes (amorphous oxide electrolytes). Crystalline oxide electrolytes include one or more types such as perovskite, NASICON, LISICON, and garnet, while glassy oxide electrolytes include LiPON type electrolytes.

[0140] In some embodiments, the oxide solid electrolyte includes Li 3.3 La 0.56 TiO3, LiTi2(PO4)3, Li 14 Zn(GeO4)4, Li7La3Zr2O 12 Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 2), Li 7-a La3Zr 2-a M a O 12 (M includes one or more of Ta and Nb; 0 < a < 2), Li b La 2 / 3-b TiO3 (0 < b < 2), LiAlO2, Li2ZrO3 and Li4Ti5O 12 One or more of them.

[0141] In some embodiments, the halide solid electrolyte includes one or more of Li3YCl6, Li3ErCl6, Li3YBr6, Li3InBr6, and Li3InCl6.

[0142] Polymer solid electrolytes (SPEs) are primarily composed of a polymer matrix and an electrolyte salt. The electrolyte salt may include lithium salts, specifically one or more of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), and lithium tetrafluoroborate (LiBF4). The electrolyte salt may also include sodium salts, specifically one or more of sodium hexafluorophosphate (NaPF6), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), and sodium tetrafluoroborate (NaBF4).

[0143] In some embodiments, the SPE includes one or more of the following: epoxy compounds, polyester compounds, polyalkoxy compounds, polyolefin compounds, polyacrylonitrile (PAN), and monoionic polymer electrolytes. For example, epoxy compounds include one or more of polyethylene oxide (PEO) and polypropylene oxide (PPO). Polyolefin compounds include one or more of polyvinylidene fluoride (PVDF) and polyvinylidene chloride (PVDC). Polyester compounds include one or more of polycarbonate compounds and polymethyl methacrylate (PMMA). Polycarbonate compounds include one or more of polypropylene carbonate and polytrimethylene carbonate.

[0144] Furthermore, the polymer matrix can be hybridized with inorganic particles, including metal oxide nanoparticles such as MgO, Al2O3, and SiO2, as well as one or more of zeolites and montmorillonite. The addition of inorganic particles can reduce crystallinity, and the interactions between the polymer matrix, lithium salt, and inorganic particles can improve conductivity and ion transference number. Inorganic particles can also adsorb trace impurities such as moisture in the electrolyte and improve mechanical properties.

[0145] In this embodiment, the polymer matrix and electrolyte salt can be added to a solvent such as N,N-dimethylformamide, dispersed evenly to obtain a slurry, and then molded to obtain a polymer solid electrolyte.

[0146] In the embodiments of this application, the electrode assembly 10 is a wound structure or a stacked structure, and can be selected as a stacked structure.

[0147] When the electrode assembly 10 has a wound structure, the positive electrode sheet is a single piece and the negative electrode sheet is a single piece, and the positive and negative electrode sheets are wound in the same direction.

[0148] When the electrode assembly 10 has a stacked structure, there are multiple positive electrode sheets and multiple negative electrode sheets, and the multiple positive electrode sheets and multiple negative electrode sheets are stacked.

[0149] like Figure 5 As shown, in some embodiments, the electrode assembly 10 includes a plurality of electrode plates and a solid electrolyte layer 50. The plurality of electrode plates are stacked along the thickness direction X of the electrode assembly 10. The solid electrolyte layer 50 is located between two adjacent electrode plates. The electrode plate includes a current collector and an active material layer disposed on at least one side of the current collector. The current collector is located on at least one side of the electrode assembly along the thickness direction.

[0150] The electrode assembly 10 has at least one current collector on one side along the thickness direction X, which can mean that the electrode assembly 10 has a current collector on one side along the thickness direction X and an active material layer on the other side; or the electrode assembly 10 has current collectors on both sides along the thickness direction X.

[0151] When at least one side of the electrode assembly 10 along the thickness direction X is a current collector, the electrode assembly 10 does not include an active material layer that cannot participate in charging and discharging outside that side, which can increase the space occupied by the active material layer that participates in charging and discharging, thereby increasing the energy density of the battery cell.

[0152] When both sides of the electrode assembly 10 along the thickness direction X are current collectors, neither side of the electrode assembly 10 includes an active material layer that cannot participate in charging and discharging, i.e. an ineffective active material layer. This can increase the space occupied by the active material layer that participates in charging and discharging, and further improve the energy density of the battery cell.

[0153] In some embodiments, the plurality of electrode plates include a plurality of first electrode plates 30 and a plurality of second electrode plates 40. The first electrode plate 30 includes a first current collector 31 and a first active material layer 32, the first active material layer 32 being disposed on at least one side of the first current collector 31 along the thickness direction X of the electrode assembly 10. The second electrode plate 40 includes a second current collector 41 and a second active material layer 42, the second active material layer 42 being disposed on at least one side of the second current collector 41 along the thickness direction X. The first electrode plates 30 and the second electrode plates 40 have opposite polarities. The plurality of first electrode plates 30 and the plurality of second electrode plates 40 are stacked along the thickness direction X.

[0154] At least one side of the electrode assembly 10 along the thickness direction X is a current collector, which can be a first current collector 31 or a second current collector 41.

[0155] like Figure 5 As shown, for example, both sides of the electrode assembly 10 along the thickness direction X are first electrode sheets 30. Specifically, both sides of the electrode assembly 10 along the thickness direction X are first current collectors 31, which are first electrode sheets 30. In other words, the first electrode sheet 30 located inside the electrode assembly 10 includes the first current collector 31 and a first active material layer 32 disposed on both sides of the first current collector 31. The first electrode sheet 30 located on both sides of the electrode assembly 10 includes the first current collector 31 and a first active material layer 32 disposed on one side of the first current collector 31. Of course, the first electrode sheet 30 located inside the electrode assembly 10 may include the first current collector 31 and the first active material layer 32 disposed on one side of the first current collector 31.

[0156] Figure 6 This is a schematic diagram of the structure of the electrode assembly in a battery cell provided for other embodiments of this application.

[0157] like Figure 6 As shown, for example, both sides of the electrode assembly 10 along the thickness direction X are second electrode sheets 40. Specifically, both sides of the electrode assembly 10 along the thickness direction X are second current collectors 41 with second electrode sheets 40. In other words, the second electrode sheet 40 located inside the electrode assembly 10 includes the second current collector 41 and a second active material layer 42 disposed on both sides of the second current collector 41. The second electrode sheet 40 located on both sides of the electrode assembly 10 includes the second current collector 41 and a second active material layer 42 disposed on one side of the second current collector 41. Of course, the second electrode sheet 40 located inside the electrode assembly 10 may include the second current collector 41 and the second active material layer 42 disposed on one side of the second current collector 41.

[0158] For example, the electrode assembly 10 has a first electrode 30 on one side along the thickness direction X and a second electrode 40 on the other side. Specifically, the electrode assembly 10 has a first current collector 31 of the first electrode 30 on one side along the thickness direction X and a second current collector 41 of the second electrode 40 on the other side. In other words, the first electrode 30 located inside the electrode assembly 10 includes the first current collector 31 and a first active material layer 32 disposed on both sides of the first current collector 31, and the second electrode 40 located inside the electrode assembly 10 includes the second current collector 41 and a second active material layer 42 disposed on both sides of the second current collector 41. Of course, the first electrode 30 located inside the electrode assembly 10 may include the first current collector 31 and the first active material layer 32 disposed on one side of the first current collector 31. The second electrode 40 located inside the electrode assembly 10 may include the second current collector 41 and the first active material layer 32 disposed on one side of the second current collector 41.

[0159] Figure 7 This is a schematic diagram of the structure of the first electrode in a battery cell provided in some other embodiments of this application.

[0160] like Figure 7 As shown, in some embodiments, the outline of the projection surface of the current collector along the thickness direction X is rectangular; for example, the outline of the projection surface of the first current collector 31 along the thickness direction X is rectangular; and for another example, the outline of the projection surface of the second current collector 41 along the thickness direction X is rectangular.

[0161] The edge or interior angle of the current collector is a right angle, i.e., 90°, which increases the area of ​​the current collector carrying the active material layer, which is beneficial to improving the energy density of the battery cell.

[0162] In the embodiments of this application, when the first electrode 30 is a positive electrode, the first current collector 31 is a positive current collector, and the first active material layer 32 is a positive active material layer; correspondingly, when the second electrode 40 is a negative electrode, the second current collector 41 is a negative current collector, and the second active material layer 42 is a negative active material layer.

[0163] When the first electrode 30 is a negative electrode, the first current collector 31 is a negative current collector, and the first active material layer 32 is a negative active material layer; correspondingly, when the second electrode 40 is a positive electrode, the second current collector 41 is a positive current collector, and the second active material layer 42 is a positive active material layer.

[0164] This application also provides a method for preparing an electrode assembly.

[0165] Figure 8 This is a schematic flowchart illustrating a method for fabricating an electrode assembly for other embodiments of this application.

[0166] like Figure 8 As shown, the preparation method includes:

[0167] Step S110: Provide an electrode assembly to be pressed, wherein at least one side of the electrode assembly to be pressed along its own thickness direction is the outermost active material layer;

[0168] Step S120: An adhesive layer is bonded onto the outermost active material layer to form an intermediate component;

[0169] Step S130: Pressing the intermediate component to obtain the pressed component, the density of the pressed component meets the first preset density.

[0170] Step S140: Remove the adhesive layer and the outermost active material layer of the pressing component to form an electrode assembly.

[0171] The embodiments of this application can increase the space occupied by the active material layer that can participate in charging and discharging by removing the outermost ineffective active material layer of the electrode assembly to be charged, thereby increasing the energy density of the battery cell.

[0172] Step S110: Provide the electrode assembly to be pressed.

[0173] In some implementations, step S110 may include:

[0174] A pressure electrode assembly is provided, wherein both sides of the pressure electrode assembly along its own thickness direction are the outermost active material layers.

[0175] In some implementations, step S110 may include:

[0176] Step S111: Provide a plurality of first electrodes, each first electrode including a first current collector and a first active material layer, the first active material layer being disposed on both sides of the first current collector along the thickness direction;

[0177] Step S112: Provide a plurality of second electrodes, each second electrode including a second current collector and a second active material layer, the second active material layer being disposed on both sides of the second current collector along the thickness direction, the polarity of the second electrodes being opposite to that of the first electrodes;

[0178] Step S113: Provide multiple solid electrolyte layers;

[0179] Step S114: Alternately stack the first electrode, the solid electrolyte layer, and the second electrode along the thickness direction to obtain the electrode assembly to be pressed.

[0180] Figure 9 This is a schematic diagram of the structure of the electrode assembly to be pressed provided in some embodiments of this application.

[0181] like Figure 9As shown, when the first electrode 30 is located at the outermost edge of the electrode assembly to be pressed along the thickness direction X, the first active material layer 32 of the first electrode 30 is located at the outermost edge of the electrode assembly to be pressed, that is, the outermost active material layer is the first active material layer 32.

[0182] When the second electrode 40 is located at the outermost edge of the electrode assembly 10 along the thickness direction X, the second active material layer 42 of the second electrode 40 is located at the outermost edge of the electrode assembly 10, that is, the outermost active material layer is the second active material layer 42.

[0183] It should be noted that in the embodiments of this application, steps S111, S112 and S113 have no order; they can occur simultaneously or in separate steps.

[0184] In some embodiments, the projection surface of the first current collector along the thickness direction is rectangular. The edges of the first current collector are right angles, which increases the overall area of ​​the active material layer supported by the first current collector, thus improving the energy density of the battery cell.

[0185] In some embodiments, the projection surface of the second current collector along the thickness direction is rectangular. The edges of the second current collector are right angles, which increases the overall area of ​​the active material layer supported by the second current collector, thus improving the energy density of the battery cell.

[0186] Step S120: An adhesive layer is provided on the electrode assembly to be pressed. The adhesive layer covers the outermost active material layer along the thickness direction. For example, the projection of the outermost active material layer along the thickness direction is located within the projection of the adhesive layer along the thickness direction, so as to facilitate the simultaneous removal of the outermost active material layer when removing the adhesive layer later.

[0187] Figure 10 This is a schematic diagram of the structure of the electrode assembly to be pressed and the adhesive layer provided in some embodiments of this application; such as Figure 10 As shown, the adhesive layer 60 is disposed on the first active material layer 32.

[0188] The adhesive layer is a film layer with a certain viscosity, enabling it to bond with the outermost active material layer. For example, the peel strength of the adhesive layer can be from 1 N / m to 80 N / m, specifically from 60 N / m to 80 N / m, such as 1 N / m, 5 N / m, 10 N / m, 15 N / m, 20 N / m, 25 N / m, 30 N / m, 35 N / m, 40 N / m, 45 N / m, 50 N / m, 55 N / m, 60 N / m, 65 N / m, 70 N / m, 75 N / m, 80 N / m, or any range of two of these values. The adhesive layer can be applied during the electrode stacking process or after the electrode stacking is completed.

[0189] In the embodiments of this application, the peel strength of the adhesive layer has a meaning known in the art and can be tested using equipment and methods known in the art, such as the test method for peel strength of adhesive tape in GB / T 2792-2014.

[0190] In some embodiments, the shrinkage rate of the adhesive layer is 2.4% to 11.5%, for example, 2.4%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, or a range of any two of the above values.

[0191] When the shrinkage rate of the adhesive layer is within the above range, its shrinkage capacity is relatively strong, and the shrinkage amplitude is relatively large during the pressing process, which is more conducive to the peeling off of the outermost active material layer.

[0192] In the embodiments of this application, the shrinkage rate of the adhesive layer has a meaning known in the art and can be tested using equipment and methods known in the art, such as in accordance with GB / T 36363-2018 Test Methods for Polyolefin Separators for Lithium-ion Batteries.

[0193] Optionally, the adhesive layer includes one or more of the following materials: polyolefin, polyimide, polyether, polylactic acid, polyacrylate, polyurethane, and ethylene-vinyl acetate copolymer.

[0194] For example, polyolefin materials include one or more of polyethylene, polypropylene, polytetrafluoroethylene, and polyvinyl chloride.

[0195] For example, polyimide materials include one or more of polyimide, polyimide ether ketone, polyetherimide, and polyimide ether sulfone.

[0196] For example, polyether materials include one or more of polyvinyl ether and polyphenylene sulfide.

[0197] Step S130, pressing process: By pressing the intermediate component, the internal density of the intermediate component is increased, the gap between the first electrode and the solid electrolyte layer is reduced, and the first electrode and the solid electrolyte layer can make surface-to-surface contact. This also reduces the gap between the second electrode and the solid electrolyte layer, allowing them to make surface-to-surface contact, which helps reduce the transport resistance of active ions at the solid-solid interface. After the pressing process, the intermediate component can form a monolithic structure.

[0198] Figure 11 This is a schematic diagram showing the state of the electrode assembly to be pressed in some embodiments of this application.

[0199] like Figure 11 As shown, the pressing process also makes the particles in the first active material layer more compact, increasing the compaction density of the first active material layer; it also makes the particles in the second active material layer more compact, increasing the compaction density of the second active material layer, thereby increasing the energy density of the battery cell. Figure 11 The arrow shown indicates the direction of the force.

[0200] The pressing process may include one or more pressing steps. In the case of multiple pressing steps, the pressing process may include pre-pressing and re-pressing. Through multiple pressing processes, the density can be improved, thereby further increasing the energy density of the battery cell.

[0201] Specifically, step S130 may include:

[0202] Step S131: Pre-compress the intermediate component until the density of the intermediate component meets the second preset density.

[0203] Step S132: The intermediate component is then pressed to obtain the pressed component. The density of the pressed component satisfies the first preset density, which is greater than the second preset density.

[0204] In step S131, optionally, the second preset density can be 60% to 85%, for example, 60%, 65%, 70%, 75%, 80%, 85%, or any range of two of the above values.

[0205] Pre-compression can be performed using either flat pressing or isostatic pressing, with flat pressing being the preferred option. Flat pressing applies force along the thickness direction to the intermediate component, making its interior more compact and allowing it to form a monolithic structure. This reduces misalignment between electrodes during subsequent processes. After pre-compression, the bonding force between the adhesive layer and the outermost active material layer is stronger, making it easier to remove the outermost active material layer when removing the adhesive layer.

[0206] For example, the flat pressing temperature is from 25°C to 200°C, such as 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, or any range of two of the above values.

[0207] For example, the pressure for the flattening process is from 3 MPa to 20 MPa, such as 3 MPa, 5 MPa, 8 MPa, 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, or any range of two of the above values.

[0208] For example, the flattening process time is from 10s to 180s, such as 10s, 20s, 50s, 80s, 100s, 120s, 150s, 180s or any range of two of the above values.

[0209] For example, the flat pressing process uses a flat pressing plate, and the parallelism of the flat pressing plate is controlled to be 0.05mm to 0.50mm, such as 0.05mm, 0.10mm, 0.20mm, 0.30mm, 0.40mm, 0.50mm or any two of the above values.

[0210] In step S132, optionally, the first preset density can be greater than or equal to 94.0% and less than 100%, and can be selected as 94.0% to 97.5%, such as 94.0%, 94.5%, 95.0%, 95.5%, 96.0%, 96.5%, 97.0%, 97.5%, 98.0%, 98.5%, 99.0%, 99.5%, or a range of any two of the above values.

[0211] The re-lamination process can be performed using either flat pressing or isostatic pressing, with isostatic pressing being the preferred option. Isostatic pressing applies force to the intermediate component in all directions, making the interior of the intermediate component more compact. After isostatic pressing, the adhesion between the adhesive layer and the outermost active material layer is stronger, making it easier to remove the outermost active material layer when peeling off the adhesive layer.

[0212] The degree of densification of the electrode assembly can be characterized by density, for example, the calculation method is as follows:

[0213]

[0214] In the formula, τ is the packing density; m is the mass; V is the volume; and ρ is the theoretical true density.

[0215] Optionally, step S132 may include:

[0216] Step S1321: Provide an encapsulation film to the intermediate component to wrap the intermediate component and form the component to be statically pressed;

[0217] Step S1322: Extract the gas from the component to be statically pressed until the vacuum level in the component meets the preset vacuum level.

[0218] Step S1323: After sealing the component to be statically pressed, the component to be statically pressed is subjected to isostatic pressing to obtain the pressed component, and the density of the pressed component meets the first preset density.

[0219] Step S1324: Remove the encapsulation film of the pressing component.

[0220] The adhesive layer is bonded to the outside of the electrode assembly to be pressed, which can effectively reduce the risk of the electrode edge piercing the encapsulation film, and can also reduce the risk of foreign matter contaminating the electrode assembly during the process; it can also buffer the force of external components impacting the electrode assembly during the process.

[0221] The encapsulation film effectively isolates intermediate components from the isostatic medium, reducing the risk of contamination of active materials in the intermediate components. Optionally, the isostatic medium may include one or more of a gaseous medium and a liquid medium. For example, the gaseous medium includes one or more inert gases, such as helium, neon, or argon. As another example, the liquid medium includes one or more of water, silicone oil, or dioctyl sebacate.

[0222] Optionally, the encapsulation film can adopt the shape and structure of the intermediate component. For example, if the intermediate component is a cuboid, the encapsulation film can adopt a similar cuboid structure. Or, if the intermediate component is a cylinder, the encapsulation film can adopt a similar cylindrical structure.

[0223] Figure 12 This is a schematic diagram of the structure of the encapsulation film provided in some embodiments of this application;

[0224] like Figure 12 As shown, the encapsulation film 70 may include an encapsulation cavity 71 and an encapsulation cover 72. The encapsulation cavity 71 contains an intermediate component, and the encapsulation cover 72 covers the encapsulation cavity 71. The encapsulation cover 72 may extend beyond the encapsulation cavity 71, which facilitates sealing of the encapsulation film 70. Optionally, the tensile strength of the encapsulation film is from 20N to 85N, for example, 20N, 25N, 30N, 35N, 40N, 45N, 50N, 55N, 60N, 65N, 70N, 75N, 80N, 85N, or any combination of two of the above values. When the tensile strength of the encapsulation film is within the above range, after sealing, some space may remain inside the component to be isostatically pressed, which can provide gas storage space for the gas extruded during the isostatic pressing process, which is beneficial for further improving density.

[0225] In the embodiments of this application, the tensile strength of the encapsulation film has a meaning known in the art and can be measured using equipment and methods known in the art. It can be tested in accordance with GB / T 36363-2018 Polyolefin separator for lithium-ion batteries.

[0226] Optionally, the encapsulation film may be made of one or more of the following materials: polyolefin, polyimide, polyphenylene sulfide, and metal.

[0227] For example, polyolefin materials include one or more of polyethylene, polypropylene, and polytetrafluoroethylene.

[0228] For example, polyimide materials include one or more of polyimide, polyimide ether ketone, polyetherimide, and polyimide ether sulfone.

[0229] For example, the metal material includes one or more of aluminum, copper, and steel.

[0230] In step S1322, the preset vacuum level can be from -100KPa to -50KPa, for example, -100KPa, -90KPa, -80KPa, -70KPa, -60KPa, -50KPa, or any range of two of the above values.

[0231] In step S1323,

[0232] For example, the isostatic pressing temperature is from 0°C to 250°C, such as 0°C, 10°C, 20°C, 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, or any combination of two of the above values.

[0233] For example, the isostatic pressure treatment pressure is from 100 MPa to 2000 MPa, such as 100 MPa, 200 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1000 MPa, 1100 MPa, 1200 MPa, 1300 MPa, 1400 MPa, 1500 MPa, 1600 MPa, 1700 MPa, 1800 MPa, 1900 MPa, 2000 MPa, or any range of two of the above values.

[0234] For example, the isostatic pressing time is from 1 min to 90 min, such as 1 min, 5 min, 8 min, 10 min, 12 min, 15 min, 18 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, or any range of two of the above values.

[0235] This application also provides a method for preparing a single battery cell.

[0236] Figure 13 This is a schematic flowchart illustrating the preparation method of a battery cell provided in other embodiments of this application; such as... Figure 13 As shown, the preparation method includes:

[0237] Step S100: Provide electrode assembly;

[0238] Step S200: Assemble the electrode assembly into the housing to prepare a battery cell.

[0239] The steps for providing the electrode assembly can adopt the electrode assembly fabrication steps described above; specifically, the method for fabricating a single battery cell can include:

[0240] Step S110: Provide an electrode assembly to be pressed, wherein at least one side of the electrode assembly to be pressed along its own thickness direction is the outermost active material layer;

[0241] Step S120: An adhesive layer is bonded onto the outermost active material layer to form an intermediate component;

[0242] Step S130: Pressing the intermediate component to obtain the pressed component, the density of the pressed component meets the first preset density.

[0243] Step S140: Remove the adhesive layer and the outermost active material layer of the pressing component to form an electrode assembly;

[0244] Step S200: Assemble the electrode assembly into the housing to prepare a battery cell.

[0245] The embodiments of this application can increase the space occupied by the active material layer that can participate in charging and discharging by removing the outermost active material layer of the electrode assembly to be charged, thereby increasing the energy density of the battery cell.

[0246] The implementation of the method for preparing the electrode assembly of this application may include:

[0247] Cut the edges of the first and second pole pieces at right angles;

[0248] The first electrode, the solid electrolyte layer, and the second electrode are stacked to form the electrode assembly to be pressed, with the outermost active material layers on both sides along the thickness direction of the electrode assembly to be pressed.

[0249] An adhesive layer is provided on both sides of the electrode assembly to be pressed to form an intermediate assembly;

[0250] The intermediate components are integrated into a single structure through pressure processing.

[0251] The intermediate components are subjected to isostatic pressing to form a pressing component, so that the density of the pressing component meets the first preset density.

[0252] Remove the adhesive layer and the outermost active material layer to form the electrode assembly.

[0253] Example

[0254] The following embodiments describe the contents disclosed in 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 the embodiments 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.

[0255] Example

[0256] 1. Fabrication of stacked electrode assemblies

[0257] The negative electrode, solid electrolyte layer, and positive electrode are stacked together, with the negative electrode located on the outermost side. The negative electrode includes a negative current collector and negative active material layers disposed on both sides of the negative current collector. The positive electrode includes a positive current collector and positive active material layers disposed on both sides of the positive current collector. The interior angles of both the positive and negative electrode are right angles.

[0258] An adhesive layer is located on the surface of the negative active material layer of the outermost negative electrode sheet, forming an intermediate component. Before lamination, an adhesive layer is placed in advance, and then the negative electrode sheet, solid electrolyte layer, positive electrode sheet and negative electrode sheet are placed on the adhesive layer in sequence. After lamination, an adhesive layer is set on the surface of the negative active material layer of the outermost negative electrode sheet.

[0259] The intermediate components for flat pressure pre-compression are integrated, with a flat pressure pre-compression temperature of 85℃, a pressure of 10MPa, a time of 60s, and a platen parallelism of 0.1mm.

[0260] The intermediate components are encapsulated with an encapsulation film to form the component to be statically pressed.

[0261] Extract the gas from the component to be statically pressed until the vacuum level inside the component is -95 kPa;

[0262] Sealing the components awaiting static pressure;

[0263] The components to be statically pressed were subjected to isostatic pressing, with silicone oil as the isostatic pressing medium, a temperature of 150℃, a pressure of 800MPa, and a time of 5min.

[0264] Remove the encapsulation film, peel off the adhesive layer, and simultaneously peel off the outermost active material layer.

[0265] 2. Preparation of stacked battery cells

[0266] The stacked electrode assembly is placed in the housing and then subjected to processes such as vacuum sealing, settling, formation, and shaping to obtain the stacked battery cell.

[0267] Comparative Example

[0268] 1. Fabrication of stacked electrode assemblies

[0269] The negative electrode, solid electrolyte layer, and positive electrode are stacked together, with the negative electrode located on the outermost side. The negative electrode includes a negative current collector and negative active material layers disposed on both sides of the negative current collector. The positive electrode includes a positive current collector and positive active material layers disposed on both sides of the positive current collector. The edges of the negative electrode and the positive electrode are chamfered, that is, their edges are rounded.

[0270] The intermediate components for flat pressure pre-compression are integrated, with a flat pressure pre-compression temperature of 85℃, a pressure of 10MPa, a time of 60s, and a platen parallelism of 0.1mm.

[0271] The intermediate component is encapsulated with an encapsulation film to form the component to be statically pressed; the gas inside the component to be statically pressed is extracted until the vacuum degree inside the component is -95KPa; the component to be statically pressed is sealed; the component to be statically pressed is subjected to isostatic pressing, with silicone oil as the isostatic medium, temperature at 150℃, pressure at 800MPa, and time at 5min; the encapsulation film is then removed.

[0272] Adhesive and adhesive are applied to the surface of the electrode assembly. The surface of the electrode assembly includes a main surface and a side surface. The area of ​​the main surface is larger than that of the side surface. The main surface and the side surface are connected. Adhesive is applied to the main surface of the electrode assembly, and adhesive is applied to the side surface of the electrode assembly.

[0273] 2. Preparation of stacked battery cells

[0274] The stacked electrode assembly is placed in the housing and then subjected to processes such as vacuum sealing, settling, formation, and shaping to obtain the stacked battery cell.

[0275] Performance testing:

[0276] 1. Flatness test of stacked electrode assembly

[0277] (1) The battery cell to be tested was placed on a marble platform and the battery cell was pressed at 2 kg·f.

[0278] (2) Using laser surface scanning, the flatness value of the battery cell is output.

[0279] Flatness can characterize the deviation of the macroscopic unevenness of the surface of a battery cell from an ideal plane. The smaller the flatness, the smoother the surface.

[0280] 2. Density testing of stacked electrode assemblies

[0281] (1) The sample was weighed using an analytical balance, and the mass m of the electrode assembly was used.

[0282] (2) Three Dimensions (3D) scan the geometric volume of the test sample, which is the volume V of the electrode assembly. The ratio of the mass m of the electrode assembly to the volume V is the apparent density m / V.

[0283] (3) The theoretical true density of the sample was determined by the helium displacement method as ρ, and the ratio of the apparent density m / V to the theoretical true density ρ was the density.

[0284] 3. Energy density of individual battery cells

[0285] As used herein, the term "energy density" refers to the volumetric (typically expressed in Wh / L) or gravimetric (typically expressed in Wh / kg) energy (Wh or mWh) delivered during each charge / discharge cycle from a battery device tester.

[0286] Taking gravimetric energy density as an example, under constant voltage (the positive electrode active material used in the examples and comparative examples is layered transition metal oxide NCM811, and the constant voltage is 4.25V), the ratio of the first-cycle discharge capacity (Ah) multiplied by the discharge voltage to the mass of the battery cell.

[0287] First-cycle discharge capacity: Charged at a constant current of 1C to 4.25V, then charged at a constant voltage of 4.25V until the current drops to 0.05C, and then discharged at a constant current of 1C to 2.8V. The capacity discharged in this process is the first-cycle discharge capacity (Ah).

[0288] Weight energy density = first-cycle discharge capacity (Ah) × discharge voltage (4.25V) / mass of battery cell (kg).

[0289] Using the method described in Example 1, multiple sets of stacked electrode assemblies S1 to S5 were prepared, and each was fabricated as a battery cell. Statistical analysis was performed, and the results are shown in Table 1.

[0290] Table 1

[0291]

[0292] In Table 1, Comparative Example 1 uses a similar pressing process to Example 1, and the density of the electrode assembly is basically the same.

[0293] The improvement in the energy density of the battery cells in the embodiments is calculated based on the energy density of the battery cells in the comparative example.

[0294] As shown in Table 1, the embodiments of this application can improve the energy density of a single battery cell by bonding the outermost active material layer with an adhesive layer.

[0295] Moreover, the adhesive layer can basically remove the outermost active material layer completely, and the flatness of the surface after removal is small, for example, less than or equal to 0.0240 mm, which can be selected from 0.01 mm to 0.025 mm, or from 0.01 mm to 0.015 mm, and the surface is relatively smooth.

[0296] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing a single battery cell, comprising: A pressure electrode assembly is provided, wherein at least one side of the pressure electrode assembly along its own thickness direction is the outermost active material layer; An adhesive layer is bonded onto the outermost active material layer to form an intermediate component; The intermediate component is pressed to obtain a pressed component, and the density of the pressed component satisfies a first preset density. Remove the adhesive layer and the outermost active material layer of the pressing assembly to form an electrode assembly; The electrode assembly is assembled into the housing to prepare a battery cell.

2. The preparation method according to claim 1, wherein, The step of pressing the intermediate component to obtain a pressed component, wherein the density of the pressed component satisfies a first preset density, includes: The intermediate component is pre-compressed until its density meets a second preset density. The intermediate component is then pressed to obtain a pressed component, and the density of the pressed component satisfies a first preset density, which is greater than a second preset density.

3. The preparation method according to claim 2, wherein, The second preset density is 60% to 85%.

4. The preparation method according to claim 2 or 3, wherein, The step of pre-compression processing the intermediate component until the density of the intermediate component meets the second preset density includes: The intermediate component is subjected to flat pressing to make its density meet a second preset density.

5. The preparation method according to claim 4, wherein, The temperature of the flattening treatment is 25°C to 200°C; and / or The pressure for the pressure treatment is 3 MPa to 20 MPa; and / or The flattening process takes 10 to 180 seconds.

6. The preparation method according to any one of claims 1 to 5, wherein, The first preset density is greater than or equal to 94.0% and less than 100%.

7. The preparation method according to claim 6, wherein, The first preset density is 94.0% to 97.5%.

8. The preparation method according to any one of claims 2 to 7, wherein, The step of re-pressing the intermediate component to obtain a pressed component, wherein the density of the pressed component satisfies a first preset density, includes: The intermediate component is subjected to isostatic pressing to obtain a pressed component, and the density of the pressed component satisfies a first preset density.

9. The preparation method according to claim 8, wherein, The step of isostatically pressing the intermediate component to obtain a pressed component, wherein the density of the pressed component satisfies a first preset density, includes: An encapsulation film is provided to the intermediate component to encapsulate the intermediate component and form the component to be statically pressed; Extract the gas from the component to be statically compressed until the vacuum level in the component meets the preset vacuum level; After sealing the component to be statically pressed, the component to be statically pressed is subjected to isostatic pressing to obtain a pressed component, and the density of the pressed component meets the first preset density. Remove the encapsulation film of the pressing component.

10. The preparation method according to claim 9, wherein, The tensile strength of the encapsulation film is 20N to 85N.

11. The preparation method according to claim 10, wherein, The encapsulation film is made of one or more of the following materials: polyolefin, polyimide, metal, and polyphenylene sulfide.

12. The preparation method according to claim 11, wherein, The polyolefin material includes one or more of polyethylene, polypropylene, and polytetrafluoroethylene; and / or The polyimide material includes one or more of polyimide, polyimide ether ketone, polyetherimide, and polyimide ether sulfone; and / or The metal material includes one or more of aluminum, copper, and steel.

13. The preparation method according to any one of claims 9 to 12, wherein, The preset vacuum level is -100 kPa to -50 kPa.

14. The preparation method according to any one of claims 8 to 13, wherein, The isostatic pressing treatment temperature is from 0°C to 250°C; and / or The isostatic pressing process is performed at a pressure of 100 MPa to 2000 MPa; and / or The isostatic pressing treatment time is from 1 minute to 90 minutes.

15. The preparation method according to any one of claims 1 to 14, wherein, The peel strength of the adhesive layer is from 1 N / m to 80 N / m; and / or the shrinkage rate of the adhesive layer is from 2.4% to 11.5%.

16. The preparation method according to claim 15, wherein, The adhesive layer comprises one or more of the following materials: polyolefin, polyimide, polyether, polylactic acid, polyacrylate, polyurethane, and ethylene-vinyl acetate copolymer.

17. The preparation method according to claim 16, wherein, The polyolefin material includes one or more of polyethylene, polypropylene, and polytetrafluoroethylene; and / or The polyimide material includes one or more of polyimide, polyimide ether ketone, polyetherimide, and polyimide ether sulfone; and / or The polyether material includes one or more of polyvinyl ether and polyphenylene sulfide.

18. The preparation method according to any one of claims 1 to 17, wherein, The step of providing a pressure-bearing electrode assembly, wherein at least one side of the pressure-bearing electrode assembly along its own thickness direction is the outermost active material layer, includes: A plurality of first electrodes are provided, each first electrode comprising a first current collector and a first active material layer, the first active material layer being disposed on both sides of the first current collector along the thickness direction; A plurality of second electrodes are provided, each second electrode including a second current collector and a second active material layer, the second active material layer being disposed on both sides of the second current collector along the thickness direction, and the polarities of the second electrodes and the first electrodes being opposite; Provides multiple solid electrolyte layers; The first electrode, the solid electrolyte layer, and the second electrode are alternately stacked along the thickness direction to obtain the electrode assembly to be pressurized. The first electrode is located on the outermost side of the electrode assembly to be pressed along the thickness direction, and the outermost active material layer is the first active material layer; or The second electrode is located on the outermost side of the electrode assembly to be pressed along the thickness direction, and the outermost active material layer is the second active material layer.

19. The preparation method according to claim 18, wherein, The outline of the projection surface of the first current collector along the thickness direction is rectangular; and / or The outline of the projection surface of the second current collector along the thickness direction is rectangular.

20. The preparation method according to any one of claims 1 to 19, wherein, The outermost active material layer includes a positive electrode active material; or the outermost active material layer includes a negative electrode active material.

21. The preparation method according to any one of claims 1 to 20, wherein, The electrode assembly to be pressed has an outermost active material layer on both sides along the thickness direction.

22. A battery cell, comprising an electrode assembly, the electrode assembly including a solid electrolyte layer and a plurality of electrode plates, the plurality of electrode plates being stacked along the thickness direction of the electrode assembly, the solid electrolyte layer being located between two adjacent electrode plates, each electrode plate including a current collector and an active material layer disposed on at least one side of the current collector, wherein, At least one side of the electrode assembly along the thickness direction is a current collector.

23. A method for preparing an electrode assembly, comprising: A pressure electrode assembly is provided, wherein at least one side of the pressure electrode assembly along its own thickness direction is the outermost active material layer; An adhesive layer is bonded onto the outermost active material layer to form an intermediate component; The intermediate component is pressed to obtain a pressed component, and the density of the pressed component satisfies a first preset density. Remove the adhesive layer and the outermost active material layer of the pressing assembly to form an electrode assembly.

24. An electrode assembly comprising a plurality of electrode sheets and a solid electrolyte layer, wherein the plurality of electrode sheets are stacked along the thickness direction of the electrode assembly, the solid electrolyte layer is located between two adjacent electrode sheets, and each electrode sheet includes a current collector and an active material layer disposed on at least one side of the current collector, wherein... At least one side of the electrode assembly along the thickness direction is a current collector.

25. A battery device comprising a battery cell obtained by the preparation method according to any one of claims 1 to 21, or a battery cell according to claim 22.

26. An electrical device comprising the battery device according to claim 25.

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