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

Abstract

A solid-state battery cell and a preparation method therefor, a battery device, and an electric device. The solid-state battery cell comprises a casing, an electrode assembly, an electrode terminal, and a heat-shrinkable film. The electrode assembly is accommodated in the casing, and the electrode assembly comprises an electrode body and a tab led out from the electrode body. The electrode terminal is provided on the casing and is connected to the tab, and a portion of the electrode terminal is located outside the casing. The heat-shrinkable film is accommodated in the casing, and the heat-shrinkable film is connected to the electrode terminal and defines an accommodating cavity. The electrode assembly is accommodated in the accommodating cavity. The solution improves the preparation efficiency of the solid-state battery cell.

Description

Solid-state battery cells and their preparation methods, battery devices and power devices Technical Field

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

[0002] With the energy crisis and the increasing demands for environmental protection, new energy batteries have received unprecedented attention. However, existing secondary batteries, which use liquid electrolytes, cannot fully meet the safety requirements. In recent years, solid-state batteries using solid electrolytes have gained widespread attention due to their higher safety.

[0003] Currently, the fabrication process of solid-state battery cells is relatively complex, which reduces the fabrication efficiency. Summary of the Invention

[0004] This application provides a solid-state battery cell, its preparation method, battery device, and power-consuming device, which can improve the preparation efficiency of solid-state battery cells.

[0005] In a first aspect, embodiments of this application provide a solid-state battery cell, which includes a housing, an electrode assembly, electrode terminals, and a heat-shrinkable film. The electrode assembly is housed within the housing and includes an electrode body and tabs extending from the electrode body. The electrode terminals are disposed on the housing and connected to the tabs, with a portion of the electrode terminals located outside the housing. The heat-shrinkable film is housed within the housing, connected to the electrode terminals, and defines a receiving cavity. The electrode assembly is housed within the receiving cavity.

[0006] In the above scheme, a heat-shrinkable film is first wrapped around the outer surface of the electrode assembly, and the heat-shrinkable film is connected to the electrode terminals to form a closed receiving cavity. Then, isostatic pressing is performed. The heat-shrinkable film shrinks when heated, which compresses the electrode assembly located in the receiving cavity, achieving densification of the electrode assembly. Finally, it is packaged to form a shell. Compared with the use of isostatic pressing film, which requires a complex process of punching the isostatic pressing film and removing the film after isostatic pressing, the embodiments of this application do not require punching the heat-shrinkable film, and the heat-shrinkable film does not need to be removed after the isostatic pressing step, simplifying the process and improving the preparation efficiency of solid-state battery cells.

[0007] In some embodiments, the solid-state battery cell further includes a first adhesive portion and a second adhesive portion. The first adhesive portion is disposed around the electrode terminal, and the heat-shrinkable film is connected to the electrode terminal through the first adhesive portion. The second adhesive portion is disposed around the electrode terminal, and the housing is connected to the electrode terminal through the second adhesive portion. The second adhesive portion is disposed on the side of the first adhesive portion away from the electrode body.

[0008] In the above solution, the connection between the heat-shrink film and the electrode terminal can be sealed by the first adhesive portion surrounding the electrode terminal; the connection between the outer casing and the electrode terminal can be sealed by the second adhesive portion surrounding the electrode terminal, thereby improving the sealing effect of the solid-state battery cell.

[0009] In some embodiments, the distance between the first adhesive portion and the second adhesive portion is D, where D satisfies: 5mm≤D≤20mm.

[0010] In the above solution, since the heating temperature when the outer shell is connected to the second adhesive part is greater than the melting temperature of the heat-shrinkable film, by limiting D to be greater than or equal to 5 mm, the first adhesive part and the second adhesive part can be kept within a suitable distance, thereby reducing the risk of heat-shrinkable film breakage or melting when sealing the outer shell. Furthermore, by limiting D to be less than or equal to 20 mm, the electrode terminals can be kept at a suitable length.

[0011] In some embodiments, the width of the first adhesive portion is L1, where L1 satisfies: 3mm≤L1≤10mm; and / or, the width of the second adhesive portion is L2, where L2 satisfies: 3mm≤L1≤10mm.

[0012] In the above solution, by limiting the width of the first adhesive portion to a suitable range, the sealing effect at the connection between the heat shrink film and the electrode terminal can be guaranteed to a certain extent; and / or, by limiting the width of the second adhesive portion to a suitable range, the sealing effect at the connection between the housing and the electrode terminal can be guaranteed to a certain extent.

[0013] In some embodiments, the width of the first adhesive portion is smaller than the width of the second adhesive portion.

[0014] In the above solution, the second adhesive part is outside the first adhesive part, and the first adhesive part is sealed in the shell. By setting the width of the first adhesive part to be smaller than the width of the second adhesive part, the sealing effect of the solid-state battery cell can be improved.

[0015] In some embodiments, the housing includes a first insulating layer, a metal layer, and a second insulating layer, with the metal layer disposed between the first and second insulating layers. The first insulating layer is disposed on the outer surface of the heat-shrinkable film, and the second insulating layer is located on the side of the metal layer opposite to the first insulating layer.

[0016] In the above scheme, the first insulating layer and the second insulating layer can ensure the insulation of the electrode assembly from the outside world to a certain extent, and the metal layer sandwiched between the first insulating layer and the second insulating layer can improve the strength of the shell.

[0017] In some embodiments, the material of the heat shrink film includes at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and polyimide.

[0018] The materials in the above scheme are prone to thermal shrinkage and have strong shrinkage capacity, which is beneficial to the densification of the electrode assembly.

[0019] In some embodiments, the thickness of the heat-shrinkable film is H, where H satisfies: 20μm≤H≤200μm.

[0020] In the above scheme, by limiting the thickness of the heat-shrinkable film to a suitable range, the densification effect of the electrode assembly can be improved.

[0021] Secondly, embodiments of this application also provide a method for preparing a solid-state battery cell, the method comprising the following steps:

[0022] Electrode terminals and electrode assemblies are provided, wherein the electrode assembly includes an electrode body and tabs extending from the electrode body;

[0023] Tabs that connect the electrode terminals to the electrode assembly;

[0024] The electrode assembly is wrapped from the outside with heat-shrink film;

[0025] The heat-shrink film is connected to the electrode terminals to form a sealed receiving cavity;

[0026] The electrode assembly is subjected to isostatic pressing.

[0027] Provide packaging film, which is then wrapped around the outside of heat-shrink film to form an outer shell.

[0028] In the above scheme, a heat-shrinkable film is first wrapped around the outer surface of the electrode assembly, and the heat-shrinkable film is connected to the electrode terminals to form a closed receiving cavity. Then, isostatic pressing is performed. The heat-shrinkable film shrinks when heated, which compresses the electrode assembly located in the receiving cavity, achieving densification of the electrode assembly. Finally, a packaging film is used to encapsulate the assembly to form a shell. Compared with the use of isostatic pressing film, which requires denting the isostatic pressing film and removing it after isostatic pressing, this embodiment of the application does not require denting the heat-shrinkable film, nor does it require removing the heat-shrinkable film after the isostatic pressing step, simplifying the process and improving the preparation efficiency of solid-state battery cells.

[0029] In some embodiments, the method further includes the following steps prior to the isostatic pressing of the electrode assembly:

[0030] Heat-shrink film is heat-treated.

[0031] In the above scheme, the heat-shrinkable film is heated before isostatic pressing to achieve the first shrinkage of the heat-shrinkable film, which makes the electrode assembly more tightly covered and improves the densification effect of the electrode assembly.

[0032] In some embodiments, the heat treatment temperature is T, where T satisfies: 80℃≤T≤200℃.

[0033] In the above scheme, by limiting the heat treatment temperature within a suitable range, the shrinkage rate of the heat shrink film during its first shrinkage can be guaranteed to a certain extent.

[0034] In some embodiments, the shrinkage rate of the heat-shrinkable film after the heat treatment step is S1, where S1 satisfies: 5% ≤ S1 ≤ 20%.

[0035] In the above scheme, by limiting the initial shrinkage of the heat-shrinkable film to a suitable range, the heat-shrinkable film can be more tightly wrapped around the outer surface of the electrode assembly.

[0036] In some embodiments, after the isostatic pressing step of the electrode assembly, the shrinkage rate of the heat shrink film is S2, where S2 satisfies: 20% ≤ S2 ≤ 50%.

[0037] In the above scheme, by limiting the shrinkage rate of the heat-shrink film during isostatic pressing within a suitable range, the densification effect of the electrode assembly can be improved.

[0038] Thirdly, embodiments of this application also provide a battery device, including a solid-state battery cell of any of the above embodiments or a solid-state battery cell prepared by any of the above embodiments.

[0039] Fourthly, embodiments of this application also provide an electrical device, including the aforementioned battery device, which is used to provide electrical energy.

[0040] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0041] 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 these drawings without creative effort.

[0042] Figure 1 is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0043] Figure 2 is an exploded view of a battery device according to some embodiments of this application;

[0044] Figure 3 is a schematic diagram of the connection between the electrode assembly and the electrode terminal in some embodiments of this application;

[0045] Figure 4 is a schematic diagram of the structure of the electrode assembly covered with heat-shrinkable film according to some embodiments of this application;

[0046] Figure 5 is a schematic diagram of the structure of a solid-state battery cell according to some embodiments of this application;

[0047] Figure 6 is an enlarged view of point A in Figure 4;

[0048] Figure 7 is a cross-sectional schematic diagram of the casing of some embodiments of this application;

[0049] Figure 8 is a schematic diagram of the preparation process of solid-state battery cells according to some embodiments of this application.

[0050] Explanation of reference numerals in the attached drawings: 1000, vehicle; 100, battery device; 200, controller; 300, motor; 10, top cover; 30, housing; 20, solid-state battery cell; 21, outer casing; 211, first insulating layer; 212, metal layer; 213, second insulating layer; 22, electrode assembly; 221, electrode body; 222, tab; 23, electrode terminal; 24, heat-shrink film; 25, first adhesive part; 26, second adhesive part. Detailed Implementation

[0051] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0052] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0053] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0054] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0055] Solid-state batteries, as one of the future development trends of power batteries, have advantages such as high density, high energy density, and good safety. With the technological advancement of solid-state batteries, higher requirements are being placed on the fabrication efficiency of solid-state battery cells. Currently, the fabrication process for solid-state battery cells involves first using a punch to press an isostatic film into a shape that matches the electrode assembly. Then, the isostatic film is coated onto the outer surface of the electrode assembly, and isostatic pressing is performed. After the isostatic pressing process is complete, the isostatic film is removed, and a casing is then added. This complex fabrication process reduces the fabrication efficiency of solid-state battery cells.

[0056] To address the aforementioned technical problems, this application provides a solid-state battery cell. The process involves first covering the outer surface of the electrode assembly with a heat-shrinkable film, which is then connected to the electrode terminals to form a closed cavity. Next, isostatic pressing is performed. The heat-shrinkable film shrinks upon heating, compressing the electrode assembly within the cavity and achieving densification. Finally, the assembly is packaged to form a casing. Compared to the complex process of using an isostatic pressing film, which requires stamping and removal after isostatic pressing, this application eliminates the need for stamping the heat-shrinkable film and removal after isostatic pressing, simplifying the process and improving the manufacturing efficiency of the solid-state battery cell.

[0057] This application provides a method for preparing a solid-state battery cell, a battery device, and an electrical device. The battery device can provide electrical energy to the electrical device or store electrical energy. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0058] In some embodiments, a solid-state battery cell includes an electrode assembly, which is formed by alternatingly stacking positive and negative electrode sheets.

[0059] A negative electrode sheet typically includes a negative current collector and a negative active material; the negative active material is coated onto the negative current collector. Specifically, the negative active material is uniformly coated onto both sides of the negative current collector, dried or air-dried, and then cut to a suitable size to obtain the negative electrode sheet. The negative active material includes at least one of pure lithium, lithium metal composite oxide, and lithium alloy.

[0060] In some embodiments, the electrode assembly includes a solid electrolyte, which may include at least one of sulfide solid electrolytes, oxide solid electrolytes, and organic solid electrolytes.

[0061] The positive electrode sheet in this application typically includes a positive current collector and a positive active material, with the positive active material coated on both sides of the positive current collector. In some embodiments, each side surface of the positive current collector includes a central active material region and a blank region surrounding the central active material region, the central active material region being used to coat the positive active material. The positive active material includes a positive active substance, a conductive agent, and a binder; the positive active substance includes a positive active substrate and a coating layer on the surface of the positive active substrate, the coating layer including an ion-conducting material.

[0062] 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, or magnesium-ion battery cells, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, cuboid / square battery cells, and pouch battery cells.

[0063] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0064] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0065] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0066] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0067] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0068] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0069] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0070] Please refer to Figure 1, which is a schematic diagram of the vehicle structure provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery device 100 is installed inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0071] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0072] Please refer to Figure 2, which is an exploded view of the device provided in some embodiments of this application. The battery device 100 includes a battery housing and a solid-state battery cell 20. In some embodiments, the battery housing may include a top cover 10 and a housing 30, with the top cover 10 and the housing 30 covering each other, and the top cover 10 and the housing 30 together defining a receiving cavity for accommodating the solid-state battery cell 20. The housing 30 may be a hollow structure with one end open, and the top cover 10 may be a plate-like structure, with the top cover 10 covering the open side of the housing 30 so that the top cover 10 and the housing 30 together define the receiving cavity; the top cover 10 and the housing 30 may also be hollow structures with one side open, with the open side of the top cover 10 covering the open side of the housing 30. Of course, the battery housing formed by the top cover 10 and the housing 30 may be of various shapes, such as a cylinder, a cuboid, etc.

[0073] Figure 3 is a schematic diagram of the connection between the electrode assembly and the electrode terminal in some embodiments of this application; Figure 4 is a schematic diagram of the structure of the electrode assembly covered with heat-shrinkable film in some embodiments of this application; Figure 5 is a schematic diagram of the structure of the solid-state battery cell in some embodiments of this application.

[0074] Referring to Figures 3-5, in a first aspect, embodiments of this application provide a solid-state battery cell 20. The solid-state battery cell 20 includes a housing 21, an electrode assembly 22, an electrode terminal 23, and a heat-shrinkable film 24. The electrode assembly 22 is housed within the housing 21 and includes an electrode body 221 and tabs 222 extending from the electrode body 221. The electrode terminal 23 is disposed on the housing 21 and connected to the tabs 222, with a portion of the electrode terminal 23 located outside the housing 21. The heat-shrinkable film 24 is housed within the housing 21, connected to the electrode terminal 23, and defines a receiving cavity, within which the electrode assembly 22 is housed.

[0075] The outer shell 21 can be a soft outer shell 21 with insulation such as aluminum-plastic film, or it can also be a hard shell such as aluminum shell.

[0076] The electrode assembly 22 is composed of multiple layers of stacked electrodes. The electrode body 221 is the part of the current collector coated with active material; the tab 222 is the part of the current collector not coated with active material, used to extract the electrical energy of the solid-state battery cell 20.

[0077] Electrode terminal 23 and tab 222 can be connected by welding, bonding, or other methods. For example, electrode terminal 23 and tab 222 partially overlap, and the connection is achieved by ultrasonic welding. Part of electrode terminal 23 is sealed within housing 21, while the other part is located outside housing 21. Electrode terminal 23 is used for electrical connection with external structures to draw electrical energy from the solid-state battery cell 20 to the outside.

[0078] The heat-shrink film 24 shrinks when heated, thus tightly covering the outer surface of the electrode assembly 22. The material of the heat-shrink film 24 is mainly a thermoplastic film. The heat-shrink film 24 can be a tubular film with openings at both ends, one end of which faces the side with the tab 222. After passing through the electrode assembly 22, the openings at both ends are melted and sealed. At the same time, the heat-shrink film 24 is connected and sealed to the electrode terminal 23.

[0079] After the heat-shrink film 24 is sealed, the electrode assembly 22 undergoes isostatic pressing. Isostatic pressing is an ultra-high pressure hydraulic technology that uses a sealed high-pressure container to form a product under ultra-high pressure conditions with uniform pressure in all directions. Isostatic pressing includes warm isostatic pressing, where special liquids or gases are used to transfer pressure during heating.

[0080] In this embodiment, the electrode assembly 22 is placed in an isostatic medium, which is then heated and pressurized to transfer heat and pressure to the electrode assembly 22. The heat-shrinkable film 24 shrinks under heat, compressing the space between the electrodes and making the originally loose electrode assembly 22 more compact. After the isostatic pressing process is completed, the outer shell 21 is sealed to the outer surface of the heat-shrinkable film 24. The isostatic medium can be any of an ester, water, or an inert gas.

[0081] Alternatively, before isostatic pressing, the heat-shrinkable film 24 can be heated to achieve the first shrinkage of the heat-shrinkable film 24, tightly covering the electrode assembly 22; then, isostatic pressing is performed to achieve the second shrinkage of the heat-shrinkable film 24, thus densifying the electrode assembly 22. The heating for the first shrinkage of the heat-shrinkable film 24 can be achieved using an oven, infrared radiation, hot air knife, etc.

[0082] The heat-shrink film 24 can shrink unidirectionally or bidirectionally, meaning it can shrink in one direction or in two opposite directions. Bidirectional shrinkage is preferred to improve shrinkage efficiency and enhance the densification effect of the electrode assembly 22.

[0083] In the above scheme, a heat-shrinkable film 24 is first wrapped around the outer surface of the electrode assembly 22, and the heat-shrinkable film 24 is connected to the electrode terminal 23 to form a closed receiving cavity. Then, an isostatic pressing process is performed. The heat-shrinkable film 24 shrinks when heated, which compresses the electrode assembly 22 located in the receiving cavity, thereby achieving densification of the electrode assembly 22. Then, it is packaged to form the outer shell 21. Compared with the use of an isostatic pressing film, which requires a punching process for the isostatic pressing film and a removal of the isostatic pressing film after the isostatic pressing process, the embodiment of this application does not require punching the heat-shrinkable film 24, and the heat-shrinkable film 24 does not need to be removed after the isostatic pressing process, which simplifies the process and improves the preparation efficiency of the solid-state battery cell 20.

[0084] Optionally, the isostatic temperature can be greater than or equal to 50℃ and less than or equal to 1000℃; the pressure can be greater than or equal to 100MPa and less than or equal to 3000MPa; and the time can be greater than or equal to 5min and less than or equal to 60min.

[0085] Optionally, after isostatic pressing, the surface of the heat shrink film 24 is cleaned to remove the isostatic pressing medium or dirt. One or more methods, such as air knife cleaning, laser cleaning, centrifugal treatment, and ultrasonic cleaning, can be used to clean the surface of the heat shrink film 24.

[0086] In some embodiments, the solid-state battery cell 20 further includes a first adhesive portion 25 and a second adhesive portion 26. The first adhesive portion 25 is disposed around the electrode terminal 23, and the heat-shrinkable film 24 is connected to the electrode terminal 23 through the first adhesive portion 25. The second adhesive portion 26 is disposed around the electrode terminal 23, and the housing 21 is connected to the electrode terminal 23 through the second adhesive portion 26. The second adhesive portion 26 is disposed on the side of the first adhesive portion 25 away from the electrode body 221.

[0087] The materials of the first adhesive portion 25 and the second adhesive portion 26 may include polyethylene, polypropylene, polyethylene terephthalate, etc.

[0088] First, a first adhesive portion 25 and a second adhesive portion 26 can be coated on the electrode terminal 23. After connecting the electrode terminal 23 to the tab 222, the heat-shrinkable film 24 can be sealed by roll welding or heat sealing, so that the opening of the heat-shrinkable film 24 is sealed, and the heat-shrinkable film 24 and the first adhesive portion 25 are fused and sealed on the electrode terminal 23. Similarly, the second adhesive portion 26 and the outer shell 21 can also be sealed by roll welding or heat sealing.

[0089] When the first adhesive portion 25 is sealed with the heat-shrink film 24 using roll welding, the amplitude can be greater than or equal to 5 μm and less than or equal to 50 μm; the air pressure can be greater than or equal to 0.5 mPa and less than or equal to 5 mPa; and the welding speed can be greater than or equal to 1 m / min and less than or equal to 10 m / min. By controlling the above-mentioned process conditions of roll welding, the shrinkage capacity of the heat-shrink film 24 can be improved.

[0090] Preferably, the amplitude can be greater than or equal to 15 μm and less than or equal to 30 μm; the air pressure can be greater than or equal to 0.5 mPa and less than or equal to 2 mPa; and the welding speed can be greater than or equal to 4 m / min and less than or equal to 6 m / min, so as to further improve the shrinkage capacity of the heat shrink film 24.

[0091] If heat sealing is used when the first adhesive part 25 is sealed with the heat shrink film 24, the temperature can be greater than or equal to 60°C and less than or equal to 200°C; the time can be greater than or equal to 5s and less than or equal to 30s, so as to improve the shrinkage capacity of the heat shrink film 24.

[0092] Preferably, the temperature can be greater than or equal to 100°C and less than or equal to 150°C; the time can be greater than or equal to 15s and less than or equal to 20s, in order to further improve the shrinkage capacity of the heat shrink film 24.

[0093] When the second adhesive part 26 is encapsulated with the outer shell 21, the encapsulation temperature can be greater than or equal to 150°C and less than or equal to 250°C; the time can be greater than or equal to 5s and less than or equal to 20s.

[0094] In the above solution, the connection between the heat shrink film 24 and the electrode terminal 23 can be sealed by the first adhesive portion 25 surrounding the electrode terminal 23; the connection between the outer shell 21 and the electrode terminal 23 can be sealed by the second adhesive portion 26 surrounding the electrode terminal 23, thereby improving the sealing effect of the solid-state battery cell 20.

[0095] Figure 6 is an enlarged view of point A in Figure 4.

[0096] As shown in Figure 6, in some embodiments, the distance between the first adhesive portion 25 and the second adhesive portion 26 is D, where D satisfies: 5mm≤D≤20mm.

[0097] D can be any value from 5mm to 20mm. For example, D can be any value from 5mm, 7mm, 10mm, 12mm, 15mm, 17mm or 20mm.

[0098] In the above solution, since the heating temperature when the outer shell 21 is connected to the second adhesive portion 26 is greater than the melting temperature of the heat-shrinkable film 24, by limiting D to be greater than or equal to 5 mm, the first adhesive portion 25 and the second adhesive portion 26 can be kept within a suitable distance, thereby reducing the risk of damage or melting of the heat-shrinkable film 24 when sealing the outer shell 21. Furthermore, by limiting D to be less than or equal to 20 mm, the electrode terminal 23 can be kept at a suitable length.

[0099] In some embodiments, the width of the first adhesive portion 25 is L1, where L1 satisfies: 3mm≤L1≤10mm; and / or, the width of the second adhesive portion 26 is L2, where L2 satisfies: 3mm≤L1≤10mm.

[0100] In the above solution, by limiting the width of the first adhesive portion 25 to a suitable range, the sealing effect at the connection between the heat shrink film 24 and the electrode terminal 23 can be guaranteed to a certain extent; and / or, by limiting the width of the second adhesive portion 26 to a suitable range, the sealing effect at the connection between the housing 21 and the electrode terminal 23 can be guaranteed to a certain extent.

[0101] In some embodiments, the width of the first adhesive portion 25 is smaller than the width of the second adhesive portion 26.

[0102] In the above solution, the second adhesive part 26 is outside the first adhesive part 25, and the first adhesive part 25 is sealed in the housing 21. By setting the width of the first adhesive part 25 to be smaller than the width of the second adhesive part 26, the sealing effect of the solid-state battery cell 20 can be improved.

[0103] Figure 7 is a cross-sectional schematic diagram of the casing of some embodiments of this application.

[0104] As shown in FIG7, in some embodiments, the outer shell 21 includes a first insulating layer 211, a metal layer 212 and a second insulating layer 213. The metal layer 212 is disposed between the first insulating layer 211 and the second insulating layer 213. The first insulating layer 211 is disposed on the outer surface of the heat shrink film 24, and the second insulating layer 213 is located on the side of the metal layer 212 away from the first insulating layer 211.

[0105] The first and second insulating films can be made of insulating materials such as polyethylene and polypropylene, and the metal layer 212 sandwiched in the middle can be made of materials such as aluminum foil and copper foil, so that the outer shell 21 is a composite film.

[0106] In the above scheme, the first insulating layer 211 and the second insulating layer 213 can ensure the insulation of the electrode assembly 22 from the outside world to a certain extent, and the metal layer 212 sandwiched between the first insulating layer 211 and the second insulating layer 213 can improve the strength of the outer shell 21.

[0107] In some embodiments, the material of the heat shrink film 24 includes at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and polyimide.

[0108] Among them, polyethylene has low cost, good chemical stability, and strong waterproof performance. Polypropylene has high mechanical strength and good heat resistance. Polyethylene terephthalate not only has good shrinkage performance but is also wear-resistant, not easily scratched or worn, and has excellent barrier properties and good dimensional stability. Polyvinyl chloride has good shrinkage performance and good flexibility. Polytetrafluoroethylene has extremely strong high-temperature resistance and good corrosion resistance. Polyimide has excellent high-temperature stability and good insulation performance.

[0109] The materials in the above scheme are prone to thermal shrinkage and have strong shrinkage capacity, which is beneficial to the densification of electrode assembly 22.

[0110] The preferred material for heat shrink film 24 is polyethylene terephthalate, which can improve the shrinkage capacity of heat shrink film 24 and also resist wear.

[0111] In some embodiments, the thickness of the heat-shrinkable film 24 is H, where H satisfies: 20μm≤H≤200μm.

[0112] H can be any value from 20μm to 200μm. For example, H can be any value among 20μm, 40μm, 80μm, 100μm, 150μm, 170μm or 200μm.

[0113] In the above scheme, by limiting the thickness of the heat-shrinkable film 24 to a suitable range, the densification effect of the electrode assembly 22 can be improved.

[0114] Figure 8 is a schematic diagram of the preparation process of solid-state battery cells according to some embodiments of this application.

[0115] As shown in Figure 8, in a second aspect, this application also provides a method for preparing a solid-state battery cell 20, the method comprising the following steps:

[0116] Electrode terminals 23 and electrode assembly 22 are provided, wherein the electrode assembly 22 includes an electrode body 221 and a tab 222 extending from the electrode body 221;

[0117] S10, tab 222 connecting electrode terminal 23 and electrode assembly 22.

[0118] Ultrasonic welding can be used to connect electrode terminal 23 to electrode tab 222. The ultrasonic welding pressure can be greater than or equal to 5 Psi and less than or equal to 50 Psi; the amplitude can be greater than or equal to 10 μm and less than or equal to 50 μm; and the energy can be greater than or equal to 150 J and less than or equal to 500 J. The welding quality between electrode terminal 23 and electrode tab 222 is characterized by tensile force, which can be greater than or equal to 100 N and less than or equal to 1000 N.

[0119] S20. The heat-shrink film 24 is wrapped around the electrode assembly 22 from the outside.

[0120] The heat-shrinkable film 24 can be a tubular film with openings at both ends, one end of which faces the side with tabs 222 and passes through the electrode assembly 22, so that the heat-shrinkable film 24 covers the outer surface of the electrode assembly 22.

[0121] S30. Connect the heat-shrinkable film 24 to the electrode terminal 23 to form a sealed receiving cavity.

[0122] The first adhesive portion 25 can be coated on the electrode terminal 23 first, and then the heat shrink film 24 can be sealed by roll welding or heat sealing, so that the opening of the heat shrink film 24 is sealed, and the heat shrink film 24 and the first adhesive portion 25 are fused and sealed on the electrode terminal 23.

[0123] S40. Perform isostatic pressing on electrode assembly 22.

[0124] The isostatic pressing temperature can be greater than or equal to 50℃ and less than or equal to 1000℃; the pressure can be greater than or equal to 100MPa and less than or equal to 3000MPa; and the time can be greater than or equal to 5min and less than or equal to 60min. After isostatic pressing, the surface of the heat shrink film 24 is cleaned to remove the isostatic pressing medium or dirt.

[0125] S50. Provide a packaging film and seal it on the outside of the heat shrink film 24 to form a shell 21.

[0126] The second adhesive portion 26 can be coated on the electrode terminal 23 first. After connecting the electrode terminal 23 and the tab 222, the outer shell 21 and the second adhesive portion 26 can be sealed by heating. The temperature of the heat sealing can be greater than or equal to 150°C and less than or equal to 250°C; the time can be greater than or equal to 5s and less than or equal to 20s.

[0127] In the above scheme, a heat-shrinkable film 24 is first wrapped around the outer surface of the electrode assembly 22, and the heat-shrinkable film 24 is connected to the electrode terminal 23 to form a closed receiving cavity. Then, an isostatic pressing process is performed. The heat-shrinkable film 24 shrinks when heated, which compresses the electrode assembly 22 located in the receiving cavity, thereby achieving densification of the electrode assembly 22. Finally, a packaging film is used to encapsulate the assembly to form the outer shell 21. Compared with the use of an isostatic pressing film, which requires denting the isostatic pressing film and removing it after isostatic pressing, this embodiment of the application does not require denting the heat-shrinkable film 24, nor does it require removing the heat-shrinkable film 24 after the isostatic pressing step. This simplifies the process and improves the preparation efficiency of the solid-state battery cell 20.

[0128] In some embodiments, the step of isostatic pressing the electrode assembly 22 is further included before heat treatment of the heat-shrinkable film 24.

[0129] Among them, heat treatment methods can include ovens, infrared radiation, hot air knives, etc.

[0130] In the above scheme, the heat shrink film 24 is heated before isostatic pressing to achieve the first shrinkage of the heat shrink film 24, which makes the electrode assembly 22 more tightly covered and improves the densification effect of the electrode assembly 22.

[0131] In some embodiments, the heat treatment temperature is T, where T satisfies: 80℃≤T≤200℃.

[0132] T can be any value from 80℃ to 200℃. For example, T can be any value from 80℃, 100℃, 120℃, 150℃, 170℃, 190℃ or 200℃.

[0133] Preferably, the heat treatment temperature T is greater than or equal to 120°C and less than or equal to 150°C.

[0134] In the above scheme, by limiting the heat treatment temperature within a suitable range, the shrinkage rate of the heat shrink film 24 during its first shrinkage can be guaranteed to a certain extent.

[0135] In some embodiments, the shrinkage rate of the heat-shrinkable film 24 after the heat treatment step is S1, where S1 satisfies: 5% ≤ S1 ≤ 20%.

[0136] S1 can be any value from 5% to 20%. For example, S1 can be any value among 5%, 7%, 10%, 12%, 15%, 18%, or 20%.

[0137] The shrinkage rate S1 of the first shrinkage during the heat treatment of the heat-shrinkable film 24 can be adjusted by controlling the heating temperature and time.

[0138] In the above scheme, by limiting the initial shrinkage of the heat shrink film 24 to a suitable range, the heat shrink film 24 can be more tightly wrapped around the outer surface of the electrode assembly 22.

[0139] In some embodiments, after the isostatic pressing step of the electrode assembly 22, the shrinkage rate of the heat shrink film 24 is S2, where S2 satisfies: 20% ≤ S2 ≤ 50%.

[0140] S2 can be any value from 20% to 50%. For example, S2 can be any value among 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0141] The shrinkage rate S2 of the heat shrink film 24 during the second shrinkage can be adjusted by controlling the temperature, pressure and time of isostatic pressing.

[0142] In the above scheme, by limiting the shrinkage rate of the heat-shrinkable film 24 to a suitable range during isostatic pressing, the densification effect of the electrode assembly 22 can be improved.

[0143] Optionally, the shrinkage rate S2 of the secondary shrinkage is greater than the shrinkage rate S1 of the primary shrinkage, which can result in a better densification effect.

[0144] Thirdly, embodiments of this application also provide a battery device 100, including a solid-state battery cell 20 of any of the above embodiments or a solid-state battery cell 20 prepared by any of the above embodiments.

[0145] Fourthly, embodiments of this application also provide an electrical device, including the aforementioned battery device 100, which is used to provide electrical energy.

[0146] According to some embodiments of this application, this application provides a solid-state battery cell 20, which includes a housing 21, an electrode assembly 22, an electrode terminal 23, and a heat-shrinkable film 24. The electrode assembly 22 is housed within the housing 21 and includes an electrode body 221 and tabs 222 extending from the electrode body 221. The electrode terminal 23 is disposed on the housing 21 and connected to the tabs 222, with a portion of the electrode terminal 23 located outside the housing 21. The heat-shrinkable film 24 is housed within the housing 21, connected to the electrode terminal 23, and defines a receiving cavity, within which the electrode assembly 22 is housed. The solid-state battery cell 20 also includes a first adhesive portion 25 and a second adhesive portion 26. The first adhesive portion 25 is disposed around the electrode terminal 23, and the heat shrink film 24 is connected to the electrode terminal 23 through the first adhesive portion 25. The second adhesive portion 26 is disposed around the electrode terminal 23, and the outer shell 21 is connected to the electrode terminal 23 through the second adhesive portion 26. The second adhesive portion 26 is disposed on the side of the first adhesive portion 25 away from the electrode body 221.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. 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 solid-state battery cell, comprising: shell; An electrode assembly, housed within the housing, the electrode assembly comprising an electrode body and tabs extending from the electrode body; An electrode terminal is disposed on the housing and connected to the electrode tab, with a portion of the electrode terminal located outside the housing; A heat-shrinkable film is housed within the housing, the heat-shrinkable film is connected to the electrode terminals and defines a receiving cavity, and the electrode assembly is housed within the receiving cavity.

2. The solid-state battery cell according to claim 1, wherein, The solid-state battery cell also includes: A first adhesive portion is disposed around the electrode terminal, and the heat-shrinkable film is connected to the electrode terminal through the first adhesive portion; A second adhesive portion is disposed around the electrode terminal, and the housing is connected to the electrode terminal through the second adhesive portion. The second adhesive portion is disposed on the side of the first adhesive portion away from the electrode body.

3. The solid-state battery cell according to claim 2, wherein, The distance between the first adhesive portion and the second adhesive portion is D, and D satisfies: 5mm≤D≤20mm.

4. The solid-state battery cell according to claim 2, wherein, The width of the first adhesive portion is L1, and L1 satisfies: 3mm≤L1≤10mm; and / or, the width of the second adhesive portion is L2, and L2 satisfies: 3mm≤L1≤10mm.

5. The solid-state battery cell according to any one of claims 2-4, wherein, The width of the first adhesive portion is smaller than the width of the second adhesive portion.

6. The solid-state battery cell according to any one of claims 2-5, wherein, The outer shell includes a first insulating layer, a metal layer, and a second insulating layer. The metal layer is disposed between the first insulating layer and the second insulating layer. The first insulating layer is disposed on the outer surface of the heat-shrinkable film, and the second insulating layer is located on the side of the metal layer opposite to the first insulating layer.

7. The solid-state battery cell according to any one of claims 1-6, wherein, The heat-shrink film is made of at least one of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, and polyimide.

8. The solid-state battery cell according to any one of claims 1-7, wherein, The thickness of the heat-shrinkable film is H, and H satisfies: 20μm≤H≤200μm.

9. A method for preparing a solid-state battery cell, wherein, The preparation method includes the following steps: Electrode terminals and electrode assemblies are provided, wherein the electrode assembly includes an electrode body and tabs extending from the electrode body; The tabs connecting the electrode terminals to the electrode assembly; The electrode assembly is wrapped from the outside with heat-shrink film; The heat-shrinkable film is connected to the electrode terminals to form a sealed receiving cavity; The electrode assembly is subjected to isostatic pressing. A packaging film is provided to encapsulate the outside of the heat-shrink film, forming a shell.

10. The preparation method according to claim 9, wherein, The step of performing isostatic pressing on the electrode assembly includes the following prior to: The heat-shrinkable film is subjected to heat treatment.

11. The preparation method according to claim 10, wherein, The heat treatment temperature is T, and T satisfies: 80℃≤T≤200℃.

12. The preparation method according to claim 10, wherein, The shrinkage rate of the heat-shrinkable film after the heat treatment step is S1, and S1 satisfies: 5% ≤ S1 ≤ 20%.

13. The preparation method according to any one of claims 9-12, wherein, After the isostatic pressing process is performed on the electrode assembly, the shrinkage rate of the heat-shrinkable film is S2, where S2 satisfies: 20% ≤ S2 ≤ 50%.

14. A battery device comprising a solid-state battery cell as described in any one of claims 1-7 or a solid-state battery cell prepared by any one of claims 8-13.

15. An electrical device comprising the battery device as claimed in claim 14, the battery device being used to provide electrical energy.

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