Battery cell, method for manufacturing battery cell, battery device and power-using device

Abstract

The present application provides a battery cell, a manufacturing method of a battery cell, a battery device and an electric device. The electrode sheet in the electrode assembly of the battery cell includes a current collector, an active material layer, a connecting layer and a solid electrolyte layer stacked in sequence. The surface of the connecting layer away from the active material layer is provided with a groove area, and the groove area is provided with an inwardly recessed groove. The solid electrolyte layer is arranged on the surface of the connecting layer away from the active material layer and covers the groove area. Part of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove. Since part of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove, not only the solid electrolyte layer in the groove area has a larger thickness, but also the solid electrolyte layer in the groove area has a larger contact area with the connecting layer. The solid electrolyte layer is not easy to fall off, which reduces the possibility of failure due to small thickness or falling off of the solid electrolyte layer, and makes it difficult for two adjacent pole pieces to overlap and short-circuit, which is conducive to improving the reliability of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a method for manufacturing a battery cell, a battery device, and an electrical device. Background Art

[0002] Battery devices have the advantages of high specific energy and high power density, and are widely used in electronic devices and transportation vehicles, such as mobile phones, laptops, electric vehicles, electric airplanes, electric ships, and electric tools.

[0003] With the continuous development of the battery industry, how to improve the reliability of battery devices has attracted more and more attention from those skilled in the art. Summary of the invention

[0004] In view of the above problems, the present application provides a battery cell, a method for manufacturing the battery cell, a battery device and an electrical device, wherein the battery cell has good reliability.

[0005] In a first aspect, some embodiments of the present application provide a battery cell, which includes a shell and an electrode assembly, the shell forming a cavity, the electrode assembly being arranged in the cavity, the electrode assembly including stacked pole pieces, the pole pieces including a current collector, an active material layer, a connecting layer and a solid electrolyte layer, the active material layer being arranged on the surface of the current collector, the connecting layer being arranged on the surface of the active material layer facing away from the current collector, a groove area being provided on the surface of the connecting layer facing away from the active material layer, the groove area being provided with an inwardly recessed groove, the solid electrolyte layer being arranged on the surface of the connecting layer facing away from the active material layer and covering the groove area, and a portion of the solid electrolyte layer entering the groove and being connected to the inner wall of the groove.

[0006] In the above structure, since the surface of the connecting layer facing away from the active material layer has a groove area with a groove, the solid electrolyte layer is arranged on the surface of the connecting layer with the groove area, and part of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove, not only the solid electrolyte layer in the groove area has a larger thickness, but also the solid electrolyte layer in the groove area and the connecting layer have a larger contact area, the solid electrolyte layer is not easy to fall off, reducing the possibility of failure of the solid electrolyte layer due to its small thickness or falling off, making it difficult for adjacent two pole pieces to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell.

[0007] According to the battery cells provided in some embodiments of the present application, the current collector includes a blank area and a coating area arranged along a first direction, the coating area is provided with an active material layer, and the blank area is not provided with an active material layer, the connecting layer includes two end faces arranged opposite to each other along the first direction, the end faces are connected to the surface of the connecting layer away from the active material layer, the groove area includes two sub-areas, the two sub-areas are respectively connected to the two end faces, so that the two sub-areas are respectively connected to the two opposite edges of the connecting layer in the first direction, so that the connecting layer is provided with grooves at the two opposite edges in the first direction.

[0008] According to the battery cell provided in some embodiments of the present application, the two sub-areas are arranged at intervals along the first direction, so that the area between the two sub-areas is not provided with a groove area, so that the surface of the connection layer away from the active material layer is not provided with a groove in the middle area of ​​the first direction, which is conducive to reducing the area of ​​the groove area. Since the groove area needs to be processed into a groove, by reducing the area of ​​the groove area, it is conducive to reducing the processing workload and reducing the production cost of the pole piece.

[0009] According to the battery cell provided by some embodiments of the present application, the two sub-regions are connected in the first direction. By connecting the two sub-regions in the first direction, the groove region formed by the two sub-regions can cover the entire surface of the connecting layer away from the active material layer, so that the entire surface of the connecting layer away from the active material layer is provided with grooves, which is conducive to increasing the thickness of the entire active material layer provided on the surface of the connecting layer away from the active material layer, and is conducive to preventing adjacent two pole pieces from overlapping and short-circuiting, and is conducive to improving the reliability of the battery cell.

[0010] According to the battery cell provided in some embodiments of the present application, the sub-region penetrates the connection layer along the second direction, and the second direction is perpendicular to the first direction. By setting the sub-region to penetrate the connection layer along the second direction, the sub-region can be formed in the entire edge region of the surface of the connection layer away from the active material layer in the first direction, so that the solid electrolyte slurry is not easy to flow away in the entire edge region of the surface of the connection layer away from the active material layer, resulting in a reduction in the thickness of the solid electrolyte layer, which is conducive to reducing the possibility of failure of the solid electrolyte layer at the edge portion of the surface of the connection layer away from the active material layer.

[0011] According to the battery cell provided in some embodiments of the present application, the area of ​​the groove region is set to A, and the area of ​​the surface of the connecting layer away from the active material layer is set to B, A / B ≥ 10%, so that the groove region occupies a sufficiently large proportion of the surface of the connecting layer away from the active material layer, and the groove region is large enough to correspond to the thinner solid electrolyte layer (mainly the edge region of the connecting layer in the first direction), so that the solid electrolyte layer covering the connecting layer can be acted on by the groove region of sufficiently large area, so that the thickness of the solid electrolyte layer in this area is increased, which is beneficial to reduce the possibility of short circuit due to overlap of adjacent two pole pieces, and is beneficial to improve the reliability of the battery cell.

[0012] According to the battery cell provided by some embodiments of the present application, a plurality of grooves are provided, and the plurality of grooves are arranged at intervals along the second direction to form a groove group. A plurality of groove groups are provided, and the plurality of groove groups are arranged at intervals along the first direction, and the second direction is perpendicular to the first direction. By making the groove group include a plurality of grooves arranged at intervals along the second direction, the groove group can be arranged on the surface of the connecting layer through the second direction. By providing a plurality of groove groups, and making the plurality of groove groups arranged at intervals along the first direction, the groove area formed by the grooves has a sufficient width in the first direction, and can act on a solid electrolyte layer of sufficient width.

[0013] According to the battery cell provided in some embodiments of the present application, the interval between two adjacent grooves in the second direction is set to E, 1μm≤E≤10000μm, and the interval between two adjacent groove groups in the first direction is set to F, 1μm≤F≤10000μm. By setting the range of the interval E between two adjacent grooves in the second direction to 1μm≤E≤10000μm, not only the grooves are arranged with sufficient density in the second direction to act on the solid electrolyte layer, but also the density of the grooves in the second direction is not too large to make the processing cost high. By setting the range of the interval F between two adjacent groove groups in the first direction to 1μm≤F≤10000μm, not only the groove groups are arranged with sufficient density in the first direction to act on the solid electrolyte layer, but also the density of the groove groups in the first direction is not too large to make the processing cost high.

[0014] According to the battery cell provided in some embodiments of the present application, the cross-sectional shape of the groove is configured as at least one of a circle, a triangle, a rectangle or a polygon, and the cross section is parallel to the surface of the connection layer away from the active material layer.

[0015] According to the battery cell provided in some embodiments of the present application, the cross-sectional shape of the groove is configured as a circle, and the diameter of the groove is set to G, 1μm≤G≤10000μm. By setting the range of the diameter G of the groove to 1μm≤G≤10000μm, not only a single groove has a sufficient size to allow the solid electrolyte slurry to enter, but also the size of the single groove is not too large to affect the structural strength of the connecting layer.

[0016] According to the battery cell provided in some embodiments of the present application, the groove penetrates the connecting layer along the second direction, and a plurality of grooves are provided. The plurality of grooves are spaced apart along the first direction, so that the plurality of grooves can more effectively reduce the possibility of the solid electrolyte slurry flowing to the blank area.

[0017] According to the battery cells provided in some embodiments of the present application, the interval between two adjacent grooves in the first direction is set to D, 1μm≤D≤10000μm, which not only ensures that the interval between the grooves in the first direction does not reduce the ability of the solid electrolyte slurry to flow to the blank area due to being too large, but also ensures that the interval between the grooves in the first direction does not reduce the structural strength of the connecting layer due to being too small.

[0018] According to the battery cells provided in some embodiments of the present application, the grooves are formed by laser grooving or chemical etching.

[0019] According to the battery cells provided in some embodiments of the present application, the size of the groove is set to C along the thickness direction of the connecting layer, 1μm≤C≤2000μm, which not only ensures that the groove has sufficient depth to accommodate the solid electrolyte layer, but also ensures that the structural strength of the connecting layer will not be destroyed due to excessive depth.

[0020] According to the battery cell provided in some embodiments of the present application, 5 μm≤C≤500 μm.

[0021] According to the battery cell provided in some embodiments of the present application, the interlayer peeling strength between the solid electrolyte layer and the connecting layer is set to H, 5N / m≤H≤10N / m, which not only makes the connection between the solid electrolyte layer and the connecting layer firm, but also makes the solid electrolyte layer not easy to fall off from the connecting layer, making it difficult for adjacent pole pieces to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell, and also ensures that the connection strength between the solid electrolyte layer and the connecting layer will not be too large, which will make the processing of the pole piece more difficult or more costly.

[0022] In a second aspect, some embodiments of the present application provide a method for manufacturing a battery cell, the method for manufacturing a battery cell comprising:

[0023] Providing a shell and a current collector with an active material layer on the surface;

[0024] Coating a connection slurry on the surface of the active material layer away from the current collector and drying it to form a connection layer;

[0025] Processing a groove in a groove area on a surface of the connecting layer facing away from the active material layer;

[0026] Coating a solid electrolyte slurry on the surface of the connecting layer away from the active material layer and drying it to obtain a pole piece with a solid electrolyte layer;

[0027] Laminating the electrode sheets to form an electrode assembly;

[0028] The electrode assembly is housed in a housing and forms a battery cell.

[0029] According to the manufacturing method of the battery cell provided by some embodiments of the present application, the current collector includes a blank area and a coating area arranged along a first direction, the coating area is provided with an active material layer, and the blank area is not provided with an active material layer, the connecting layer includes two end faces arranged opposite to each other along the first direction, the end faces are connected to the surface of the connecting layer away from the active material layer, the groove area includes two sub-areas, and the two sub-areas are respectively connected to the two end faces, and the step of machining and forming the groove in the groove area on the surface of the connecting layer away from the active material layer includes:

[0030] A groove is machined in the sub-area.

[0031] According to the manufacturing method of the battery cell provided in some embodiments of the present application, the groove is processed by laser grooving or chemical etching.

[0032] In a third aspect, some embodiments of the present application provide a battery device, which includes a battery cell provided by any of the above technical solutions.

[0033] In a fourth aspect, some embodiments of the present application provide an electrical device, which includes a battery device provided by any of the above technical solutions, and the battery device is used to provide electrical energy.

[0034] The technical solution provided by the embodiments of the present disclosure brings at least the following beneficial effects:

[0035] Some embodiments of the present application provide a battery cell, which includes a shell and an electrode assembly, the electrode assembly is arranged in a cavity formed by the shell, the electrode assembly includes stacked pole pieces, the pole pieces include a current collector, an active material layer, a connecting layer and a solid electrolyte layer, the active material layer is arranged on the surface of the current collector, the connecting layer is arranged on the surface of the active material layer facing away from the current collector, the surface of the connecting layer facing away from the active material layer is provided with a groove area, the groove area is provided with an inwardly concave groove, the solid electrolyte layer is arranged on the surface of the connecting layer facing away from the active material layer and covers the groove area, and a portion of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove.

[0036] In the above structure, since the surface of the connecting layer facing away from the active material layer has a groove area with a groove, the solid electrolyte layer is arranged on the surface of the connecting layer with the groove area, and part of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove, not only the solid electrolyte layer in the groove area has a larger thickness, but also the solid electrolyte layer in the groove area and the connecting layer have a larger contact area, the solid electrolyte layer is not easy to fall off, reducing the possibility of failure of the solid electrolyte layer due to its small thickness or falling off, making it difficult for adjacent two pole pieces to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell.

[0037] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0039] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0040] Figure 2 An exploded view of a battery device provided in some embodiments of the present application;

[0041] Figure 3 A disassembled diagram of a battery cell provided in some embodiments of the present application;

[0042] Figure 4 A partial structural top view of a pole piece provided in some embodiments of the present application;

[0043] Figure 5 A cross-sectional view of a pole piece provided in some embodiments of the present application;

[0044] Figure 6 A cross-sectional view of a pole piece provided in some other embodiments of the present application;

[0045] Figure 7 A cross-sectional view of a connection layer in a pole piece provided in some embodiments of the present application;

[0046] Figure 8 A cross-sectional view of a connection layer in a pole piece provided in some other embodiments of the present application;

[0047] Fig. 9 A flow chart of a method for manufacturing a battery cell provided in some other embodiments of the present application.

[0048] In the figure:

[0049] 1. Vehicle; 2. Battery device; 3. Controller; 4. Motor; 5. Box; 5a. First box part; 5b. Second box part; 5c. Accommodation space; 7. Battery cell; 71. Shell; 72. Cavity; 73. Electrode assembly; 731. Pole piece; 7311. Current collector; 73111. Blank area; 73112. Coating area; 7312. Active material layer; 7313. Connecting layer; 73131. Groove area; 73132. Groove; 73133. Sub-area; 73134. Trough group; 7314. Solid electrolyte layer; X, first direction; Y, second direction. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0052] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0053] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0054] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0055] In the embodiments of the present application, the same reference numerals represent 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 the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0056] In the embodiments of the present application, "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; at the same time, "perpendicular" also includes not only the absolutely perpendicular situation, but also the roughly perpendicular situation conventionally recognized in engineering. For example, if the angle between two directions is 85°-90°, the two directions can be considered perpendicular; if the angle between two directions is 0°-5°, the two directions can be considered parallel.

[0057] The term “plurality” used in this application refers to two or more (including two).

[0058] At present, from the perspective of market development, the application of battery devices is becoming more and more extensive. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields.

[0059] The battery device mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include a plurality of battery cells, and the plurality of battery cells are connected in series, in parallel or in mixed connection through a busbar.

[0060] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0061] The battery cell may be a secondary battery cell, which refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0062] The battery cells may be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0063] A battery cell generally includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode and a negative electrode. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and released back and forth between the positive electrode and the negative electrode. The electrolyte plays the role of conducting ions between the positive and negative electrodes. This application does not have any specific restrictions on the type of electrolyte, which can be selected according to needs. The electrolyte can be liquid, gel or solid.

[0064] A solid-state battery cell includes pole pieces and solid electrolytes, wherein the pole pieces are stacked to form an electrode assembly, and a solid electrolyte is disposed between two adjacent pole pieces to conduct ions between the two adjacent pole pieces.

[0065] The electrode assembly may be a wound structure, a laminated structure, or a mixed structure of a wound structure and a laminated structure.

[0066] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery.

[0067] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, and the battery cell assembly is accommodated in the case. As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the case by fixing the battery module in the case. As an example, the battery cell assembly may also be accommodated in the case by directly fixing a plurality of battery cells to the case.

[0068] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0069] In some embodiments, the battery device may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0070] With the rapid development of the battery industry, people have higher and higher requirements on the energy density of battery cells, and the thickness of solid electrolytes has shown a trend of thinning. However, this can easily lead to failure of the solid electrolyte and cause overlapping of adjacent pole pieces and short circuit, which is not conducive to improving the reliability of battery cells.

[0071] In order to improve the reliability of a battery cell, some embodiments of the present application provide a battery cell, which includes a shell and an electrode assembly, the electrode assembly is arranged in a cavity formed by the shell, the electrode assembly includes stacked pole pieces, the pole pieces include a current collector, an active material layer, a connecting layer and a solid electrolyte layer, the active material layer is arranged on the surface of the current collector, the connecting layer is arranged on the surface of the active material layer facing away from the current collector, the surface of the connecting layer facing away from the active material layer is provided with a groove area, the groove area is provided with an inwardly recessed groove, the solid electrolyte layer is arranged on the surface of the connecting layer facing away from the active material layer and covers the groove area, and a portion of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove. In the above structure, since the surface of the connecting layer facing away from the active material layer has a groove area with a groove, the solid electrolyte layer is arranged on the surface of the connecting layer with the groove area, and part of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove, not only the solid electrolyte layer in the groove area has a larger thickness, but also the solid electrolyte layer in the groove area and the connecting layer have a larger contact area, the solid electrolyte layer is not easy to fall off, reducing the possibility of failure of the solid electrolyte layer due to its small thickness or falling off, making it difficult for adjacent two pole pieces to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell.

[0072] The battery cells described in the embodiments of the present application are suitable for use in battery devices and electrical devices using the battery devices.

[0073] The electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the like; the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like; the electric tool may include a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0074] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0075] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0076] like Figure 1As shown, a battery device 2 is disposed inside the vehicle 1, and the battery device 2 may be disposed at the bottom, head, or tail of the vehicle 1. The battery device 2 may be used to power the vehicle 1, for example, the battery device 2 may be used as an operating power source for the vehicle 1.

[0077] The vehicle 1 may further include a controller 3 and a motor 4 , wherein the controller 3 is used to control the battery device 2 to supply power to the motor 4 , for example, to meet the power requirements of starting, navigating and driving the vehicle 1 .

[0078] In some embodiments of the present application, the battery device 2 can not only serve as an operating power source for the vehicle 1, but also serve as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0079] Figure 2 This is a schematic diagram of the disassembled structure of a battery device provided in some embodiments of the present application. Figure 2 As shown, the battery device 2 includes a housing 5 and a battery cell 7, and the battery cell 7 is accommodated in the housing 5. The battery cell 7 may be the smallest unit constituting the battery.

[0080] The box 5 is used to accommodate the battery cell 7, and the box 5 can be of various structures. In some embodiments, the box 5 can include a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b cover each other, and the first box portion 5a and the second box portion 5b jointly define a storage space 5c for accommodating the battery cell 7. The second box portion 5b can be a hollow structure with one end open, the first box portion 5a is a plate-like structure, and the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c; the first box portion 5a and the second box portion 5b can also be hollow structures with one side open, and the open side of the first box portion 5a covers the open side of the second box portion 5b to form a box 5 with a storage space 5c. Of course, the first box portion 5a and the second box portion 5b can be of various shapes, such as a cylinder, a cuboid, etc.

[0081] In order to improve the sealing performance after the first box body part 5a and the second box body part 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body part 5a and the second box body part 5b.

[0082] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box.

[0083] In the battery device 2, the battery cell 7 can be one or more. If there are more than one battery cell 7, the battery cells 7 can be connected in series, in parallel or in mixed connection. Mixed connection means that the battery cells 7 are both connected in series and in parallel. The battery cells 7 can be directly connected in series, in parallel or in mixed connection, and then the whole formed by the battery cells 7 can be accommodated in the box 5; of course, the battery cells 7 can also be connected in series, in parallel or in mixed connection to form a battery module, and then the battery modules can be connected in series, in parallel or in mixed connection to form a whole, and then accommodated in the box 5.

[0084] Some embodiments of the present application provide a battery cell 7, referring to Figure 3 The battery cell 7 includes a shell 71 and an electrode assembly 73, the shell 71 forms a cavity 72, the electrode assembly 73 is arranged in the cavity 72, the electrode assembly 73 includes a stacked pole piece 731, the pole piece 731 includes a current collector 7311, an active material layer 7312, a connecting layer 7313 and a solid electrolyte layer 7314, the active material layer 7312 is arranged on the surface of the current collector 7311, and the connecting layer 7313 is arranged on the surface of the active material layer 7312 away from the current collector 7311, Figure 4 and Figure 5 A groove area 73131 is provided on the surface of the connecting layer 7313 facing away from the active material layer 7312, and the groove area 73131 is provided with an inwardly recessed groove 73132. The solid electrolyte layer 7314 is arranged on the surface of the connecting layer 7313 facing away from the active material layer 7312 and covers the groove area 73131. A portion of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132.

[0085] The shell 71 may be a component of the battery cell 7 for enclosing a sealed cavity 72, and the cavity 72 is used to accommodate other components such as the electrode assembly 73 in the battery cell 7. The shell 71 may be in various shapes and sizes, such as a rectangular parallelepiped, a hexagonal prism, etc. Specifically, the shape of the shell 71 may be determined according to the specific shape and size of the electrode assembly 73. The shell 71 may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0086] The electrode assembly 73 is a component where electrochemical reactions occur in the battery cell 7. The housing 71 forms a cavity 72 that may contain one or more electrode assemblies 73. The electrode assembly 73 may be a winding structure, a laminated structure, or a mixed structure of winding and laminated structures.

[0087] The electrode assembly 73 includes a stacked positive electrode sheet 731 and a negative electrode sheet 731. In the electrode assembly 73 in a wound structure, the stacked positive electrode sheet 731 and the negative electrode sheet 731 are wound in a wound structure.

[0088] In the electrode assembly 73 in a laminated structure, a plurality of positive electrode sheets 731 and a plurality of negative electrode sheets 731 are provided respectively, and a plurality of positive electrode sheets 731 and a plurality of negative electrode sheets 731 are alternately stacked. Exemplarily, a plurality of positive electrode sheets 731 can be provided, and a negative electrode sheet 731 can be folded to form a plurality of stacked folded sections, with a positive electrode sheet 731 sandwiched between adjacent folded sections. As an example, both the positive electrode sheet 731 and the negative electrode sheet 731 are folded to form a plurality of stacked folded sections.

[0089] Exemplarily, the shape of the electrode assembly 73 may be cylindrical, flat, or polygonal.

[0090] The pole piece 731 may be the positive pole piece 731 or the negative pole piece 731 in the aforementioned technical solution. The current collector 7311 may be a matrix structure in the pole piece 731, which is used to carry and set other structural parts such as the active material layer 7312 in the pole piece 731, and can conduct and collect the current generated by the active material. The current collector 7311 may be a metal foil, such as copper foil and aluminum foil, or a composite current collector 7311 formed by a polymer material base layer and a metal layer.

[0091] The current collector 7311 has two surfaces that are relatively spaced apart in the thickness direction. The surfaces can be used to set the active material layer 7312 so that the active material layer 7312 can be supported on the first current collector 7311 .

[0092] The active material layer 7312 may be a layered structure formed by an active material, and may be disposed on one surface of the current collector 7311 , or may be disposed on both opposite surfaces of the current collector 7311 .

[0093] The connection layer 7313 may be a coating structure, which is used to connect the solid electrolyte layer 7314 to the structural layer on the active material layer 7312, and is used to improve the bonding strength between the solid electrolyte layer 7314 and the active material layer 7312. The connection layer 7313 can make the surface of the active material layer 7312 away from the current collector 7311 flat and smooth, and make up for the unevenness of the surface of the active material layer 7312 away from the current collector 7311. Exemplarily, the connection layer 7313 may include an adhesive and conductive graphite, so that the connection layer 7313 can not only bond the active material layer 7312 and the solid electrolyte layer 7314 together, but also conduct electricity.

[0094] The solid electrolyte layer 7314 may be a structural layer arranged between the positive electrode sheet 731 and the negative electrode sheet 731, which can simultaneously play the role of transmitting ions and isolating the positive and negative electrodes. By making the electrode sheet 731 include the solid electrolyte layer 7314, the solid electrolyte layer 7314 is arranged on the surface of the active material layer 7312 away from the current collector 7311, so that the electrode sheet 731 is a composite electrode sheet 731 with a solid electrolyte layer 7314, so that the electrode sheet 731 itself has insulation, and it is also beneficial to reduce the thickness of the electrode assembly 73, which helps to improve the energy density of the battery cell 7.

[0095] The groove area 73131 may refer to at least a partial area of ​​the surface of the connecting layer 7313 away from the active material layer 7312, in which an inwardly recessed groove 73132 is provided, so that when the solid electrolyte layer 7314 is arranged on the surface of the connecting layer 7313 away from the active material layer 7312, the solid electrolyte layer 7314 covering the groove area 73131 can partially enter the groove 73132 and be connected to the inner wall of the groove 73132, which increases the thickness of the solid electrolyte corresponding to the groove area 73131; in addition, part of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132, which can also increase the contact area between the solid electrolyte layer 7314 and the connecting layer 7313, which is beneficial to increase the connection strength between the solid electrolyte layer 7314 and the connecting layer 7313, so that the solid electrolyte layer 7314 is not easy to fall off.

[0096] In the above structure, since the surface of the connecting layer 7313 facing away from the active material layer 7312 has a groove area 73131 with a groove 73132, the solid electrolyte layer 7314 is arranged on the surface of the connecting layer 7313 having the groove area 73131, and part of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132, not only the solid electrolyte layer 7314 in the groove area 73131 has a larger thickness, but also the solid electrolyte layer 7314 in the groove area 73131 has a larger contact area with the connecting layer 7313, the solid electrolyte layer 7314 is not easy to fall off, reducing the possibility of failure of the solid electrolyte layer 7314 due to its small thickness or falling off, making it difficult for adjacent two pole pieces 731 to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell 7.

[0097] In some embodiments, reference Figure 5 and Figure 6The current collector 7311 includes a blank area 73111 and a coating area 73112 arranged along the first direction X, the coating area 73112 is provided with an active material layer 7312, and the blank area 73111 is not provided with an active material layer 7312, the connecting layer 7313 includes two end faces arranged opposite to each other along the first direction X, the end faces are connected to the surface of the connecting layer 7313 away from the active material layer 7312, and the groove area 73131 includes two sub-areas 73133, and the two sub-areas 73133 are respectively connected to the two end faces.

[0098] The coated area 73112 and the blank area 73111 may be two different parts of the current collector 7311 that are connected to each other. The coated area 73112 may be a part coated with the active material layer 7312, and the blank area 73111 may be a part that is not coated with the positive electrode active material layer 7312. By arranging the coated area 73112 and the blank area 73111 along the first direction X, the current collector 7311 has different parts arranged in sequence in the first direction X. Exemplarily, the blank area 73111 may form a pole ear extending outward along the first direction X, and the pole ear is used to be electrically connected to the electrode terminal to output the current of the pole piece 731 to the outside.

[0099] The end faces may be two surfaces of the connection layer 7313 that are oppositely arranged along the first direction X. The end faces are connected to the surface of the connection layer 7313 that is away from the active material layer 7312 . The material of the connection layer 7313 is located between the two end faces in the first direction X.

[0100] The sub-region 73133 may be a partial region in the groove region 73131. The groove region 73131 may include two sub-regions 73133, and the two sub-regions 73133 are respectively connected to the two end faces, so that the two sub-regions 73133 are respectively connected to the two opposite edges of the connecting layer 7313 in the first direction X, so that the connecting layer 7313 is provided with grooves 73132 at the two opposite edges in the first direction X.

[0101] Since the solid electrolyte layer 7314 is usually formed by a coating process, the solid electrolyte layer 7314 is formed by coating the solid electrolyte slurry on the surface of the connection layer 7313 away from the active material layer 7312 and drying it. A groove 73132 is provided on the sub-area 73133 connected to the edge of the connection layer 7313 in the first direction X, so that when the solid electrolyte slurry is coated on the edge of the connection layer 7313 in the first direction X, the solid electrolyte slurry will flow into the groove 73132, forming an interlocking force with the connection layer 7313, reducing the fluidity of the solid electrolyte slurry, and the solid electrolyte slurry is not easy to flow from the edge of the connection layer 7313 in the first direction X to the blank area 73111, which is conducive to reducing the thickness reduction of the solid electrolyte layer 7314 caused by the flow of the solid electrolyte slurry.

[0102] In some embodiments, reference Figure 7 , the two sub-areas 73133 are arranged at intervals along the first direction X.

[0103] Since the solid electrolyte layer 7314 is usually formed by a coating process, the loss of the solid electrolyte slurry usually occurs at the edge of the connecting layer 7313 in the first direction X.

[0104] By arranging two sub-areas 73133 at intervals along the first direction X, so that the area between the two sub-areas 73133 is not provided with the groove area 73131, the surface of the connection layer 7313 away from the active material layer 7312 is not provided with the groove 73132 in the middle area of ​​the first direction X, which is conducive to reducing the area of ​​the groove area 73131. Since the groove area 73131 needs to be processed to form the groove 73132, by reducing the area of ​​the groove area 73131, it is conducive to reducing the processing workload and reducing the production cost of the pole piece 731.

[0105] In some embodiments, reference Figure 8 , in the first direction X, the two sub-areas 73133 are connected.

[0106] By connecting the two sub-areas 73133 in the first direction X, the groove area 73131 formed by the two sub-areas 73133 can cover the surface of the entire connecting layer 7313 away from the active material layer 7312, so that the entire surface of the connecting layer 7313 away from the active material layer 7312 is provided with grooves 73132, which is beneficial to increase the thickness of the entire active material layer 7312 arranged on the surface of the connecting layer 7313 away from the active material layer 7312, which is beneficial to prevent adjacent two pole pieces 731 from overlapping and short-circuiting, and is beneficial to improving the reliability of the battery cell 7.

[0107] In some embodiments, along the second direction Y, the sub-region 73133 penetrates the connection layer 7313 , and the second direction Y is perpendicular to the first direction X.

[0108] The second direction Y may be a direction perpendicular to the first direction X along the surface of the connection layer 7313 away from the active material layer 7312. By setting the sub-area 73133 to penetrate the connection layer 7313 along the second direction Y, the sub-area 73133 can be formed in the entire edge region of the surface of the connection layer 7313 away from the active material layer 7312 in the first direction X, so that the solid electrolyte slurry is not easy to flow away in the entire edge region of the surface of the connection layer 7313 away from the active material layer 7312, resulting in a reduction in the thickness of the solid electrolyte layer 7314, which is conducive to reducing the possibility of failure of the solid electrolyte layer 7314 at the edge portion of the surface of the connection layer 7313 away from the active material layer 7312.

[0109] In some embodiments, the area of ​​the groove region 73131 is set to A, the area of ​​the surface of the connection layer 7313 facing away from the active material layer 7312 is set to B, and A / B≥10%.

[0110] By setting the area of ​​the groove region 73131 to A, setting the area of ​​the surface of the connecting layer 7313 away from the active material layer 7312 to B, and setting the relationship between the area of ​​the groove region 73131 and the area of ​​the surface of the connecting layer 7313 away from the active material layer 7312 to A / B≥10%, the groove region 73131 occupies a sufficiently large proportion of the surface of the connecting layer 7313 away from the active material layer 7312, and the groove region 73131 is large enough to correspond to the thinner solid electrolyte layer 7314 (mainly the edge region of the connecting layer 7313 in the first direction X), so that the solid electrolyte layer 7314 covering the connecting layer 7313 can be acted on by the groove region 73131 with a sufficiently large area, so that the thickness of the solid electrolyte layer 7314 in this region is increased, which is beneficial to reduce the possibility of short circuit due to overlap of adjacent two pole pieces 731, and is beneficial to improve the reliability of the battery cell 7.

[0111] Exemplarily, A / B ≥ 20%.

[0112] By setting the relationship between the area of ​​the groove area 73131 and the area of ​​the surface of the connecting layer 7313 away from the active material layer 7312 to A / B≥20%, the groove area 73131 occupies a sufficiently large proportion of the surface of the connecting layer 7313 away from the active material layer 7312, and the groove area 73131 is large enough to correspond to the thinner solid electrolyte layer 7314, so that the solid electrolyte layer 7314 covering the connecting layer 7313 can be acted on by the groove area 73131 with a sufficiently large area, so that the thickness of the solid electrolyte layer 7314 in this area is increased, which is beneficial to reduce the possibility of short circuit due to overlap of adjacent two pole pieces 731, and is beneficial to improve the reliability of the battery cell 7.

[0113] In some embodiments, reference Figure 7 There are multiple grooves 73132, and the multiple grooves 73132 are arranged at intervals along the second direction Y to form a groove group 73134. There are multiple groove groups 73134, and the multiple groove groups 73134 are arranged at intervals along the first direction X. The second direction Y is perpendicular to the first direction X.

[0114] By providing a plurality of grooves 73132 in the groove area 73131 , the grooves 73132 can function well to accommodate the solid electrolyte layer 7314 .

[0115] The groove group 73134 may be a combination of a plurality of grooves 73132 spaced apart along the second direction Y. The plurality of grooves 73132 may be the same type of grooves 73132 or different grooves 73132. Those skilled in the art may set the grooves according to actual conditions. By making the groove group 73134 include a plurality of grooves 73132 spaced apart along the second direction Y, the groove group 73134 can be arranged on the surface of the connection layer 7313 along the second direction Y.

[0116] By providing a plurality of groove groups 73134 and arranging the plurality of groove groups 73134 at intervals along the first direction X, the groove area 73131 formed by the groove 73132 has a sufficient width in the first direction X and can act on the solid electrolyte layer 7314 of sufficient width.

[0117] In some embodiments, the interval between two adjacent grooves 73132 in the second direction Y is set to E, 1 μm≤E≤10000 μm, and the interval between two adjacent groove groups 73134 in the first direction X is set to F, 1 μm≤F≤10000 μm.

[0118] The interval between two adjacent grooves 73132 in the second direction Y is set to E, which means that the interval between two adjacent grooves 73132 in the groove group 73134 in the second direction Y is E. By setting the range of the interval E between two adjacent grooves 73132 in the second direction Y to 1 μm ≤ E ≤ 10000 μm, not only the grooves 73132 are arranged with sufficient density in the second direction Y to act on the solid electrolyte layer 7314, but also the density of the grooves 73132 in the second direction Y is not too large to make the processing cost high.

[0119] By setting the interval F between two adjacent groove groups 73134 in the first direction X to 1μm≤F≤10000μm, not only can the groove groups 73134 be arranged with sufficient density in the first direction X to act on the solid electrolyte layer 7314, but also the density of the groove groups 73134 in the first direction X will not be too large to increase the processing cost.

[0120] In some embodiments, the cross-sectional shape of the groove 73132 is configured to be at least one of a circle, a triangle, a rectangle, or a polygon, and the cross-sectional shape is parallel to the surface of the connection layer 7313 facing away from the active material layer 7312 .

[0121] The cross section of the groove 73132 refers to a cross section parallel to the surface of the connection layer 7313 away from the active material layer 7312. The cross-sectional shape of the groove 73132 is configured as at least one of a circle, a triangle, a rectangle, or a polygon. The cross-sectional shapes of the plurality of grooves 73132 on the surface of the connection layer 7313 away from the active material layer 7312 may all be circles, triangles, rectangles, or polygons. The cross-sectional shapes of the plurality of grooves 73132 on the surface of the connection layer 7313 away from the active material layer 7312 may also include two, three, or four of the circles, triangles, rectangles, or polygons.

[0122] Exemplarily, the cross-sectional shape of the groove 73132 may also be configured as other irregular closed curves, and those skilled in the art may set the cross-sectional shape of the groove 73132 according to actual conditions.

[0123] In some embodiments, the cross-sectional shape of the groove 73132 is configured as a circle, and the diameter of the groove 73132 is set to G, 1 μm≤G≤10000 μm.

[0124] By configuring the cross-sectional shape of the groove 73132 to be circular, the groove 73132 can be a cylindrical groove, a conical groove, or a hemispherical groove.

[0125] By setting the range of the diameter G of the groove 73132 to 1μm≤G≤10000μm, not only a single groove 73132 has a sufficient size to allow the solid electrolyte slurry to enter, but also the size of the single groove 73132 is not too large to affect the structural strength of the connecting layer 7313.

[0126] In some embodiments, reference Figure 8 The groove 73132 penetrates the connection layer 7313 along the second direction Y, and a plurality of grooves 73132 are provided, and the plurality of grooves 73132 are arranged at intervals along the first direction X.

[0127] By making the groove 73132 penetrate the connecting layer 7313 along the second direction Y, the groove 73132 is made into a through groove extending along the second direction Y, so that the solid electrolyte slurry flows along the second direction Y after entering the groove 73132 and is not easy to flow along the first direction X to the blank area 73111, which is beneficial to reduce the reduction in the thickness of the solid electrolyte layer 7314 caused by the solid electrolyte slurry flowing to the blank area 73111.

[0128] By arranging the plurality of grooves 73132 at intervals along the first direction X, the plurality of grooves 73132 can effectively reduce the possibility of the solid electrolyte slurry flowing to the blank area 73111 .

[0129] Exemplarily, the plurality of grooves 73132 are arranged at equal intervals along the first direction X, so that the ability of the grooves 73132 to block the flow of the solid electrolyte slurry in the first direction X is uniformly arranged.

[0130] In some embodiments, the interval between two adjacent grooves 73132 in the first direction X is set to D, and 1 μm≤D≤10000 μm.

[0131] By setting the range of the interval D between two adjacent grooves 73132 in the first direction X to 1μm≤D≤10000μm, not only the interval between the grooves 73132 in the first direction X will not be too large to reduce the ability of reducing the flow of solid electrolyte slurry to the blank area 73111, but also the interval between the grooves 73132 in the first direction X will not be too small to reduce the structural strength of the connecting layer 7313.

[0132] In some embodiments, the groove 73132 is formed by laser engraving or chemical etching.

[0133] The groove 73132 is formed by laser grooving, which may mean that the groove 73132 is formed by processing the surface of the connection layer 7313 away from the active material layer 7312 using a laser. The groove 73132 is formed by chemical etching, which may mean that the groove 73132 is formed by corroding the surface of the connection layer 7313 away from the active material layer 7312 with a chemical reagent.

[0134] In some embodiments, along the thickness direction of the connection layer 7313 , the size of the groove 73132 is set to C, 1 μm≤C≤2000 μm.

[0135] By setting the range of the dimension C of the groove 73132 along the thickness direction of the connecting layer 7313 to 1μm≤C≤2000μm, not only the groove 73132 has sufficient depth to accommodate the solid electrolyte layer 7314, but also the groove 73132 will not destroy the structural strength of the connecting layer 7313 due to excessive depth.

[0136] In some embodiments, 5 μm ≤ C ≤ 500 μm.

[0137] By setting the range of the dimension C of the groove 73132 along the thickness direction of the connecting layer 7313 to 5μm≤C≤500μm, exemplarily, the dimension C of the groove 73132 along the thickness direction of the connecting layer 7313 can be 5μm, 100μm, 200μm, 300μm, 400μm or 500μm. Those skilled in the art can set the dimension of the groove 73132 along the thickness direction of the connecting layer 7313 according to actual conditions such as the thickness of the connecting layer 7313, so that the groove 73132 has sufficient depth to accommodate the solid electrolyte layer 7314 while not destroying the structural strength of the connecting layer 7313 due to excessive depth.

[0138] In some embodiments, the interlayer peeling strength between the solid electrolyte layer 7314 and the connecting layer 7313 is set to H, 5N / m≤H≤10N / m.

[0139] Exemplarily, the interlayer peel strength between the solid electrolyte layer 7314 and the connecting layer 7313 can be measured according to the national standard GB / T 2792-2014. The specific measurement method can be carried out with reference to the national standard GB / T 2792-2014, which will not be repeated here.

[0140] By setting the interlayer peeling strength H between the solid electrolyte layer 7314 and the connecting layer 7313 to a range of 5N / m≤H≤10N / m, not only the connection between the solid electrolyte layer 7314 and the connecting layer 7313 is made firm, the solid electrolyte layer 7314 is not easily detached from the connecting layer 7313, and adjacent pole pieces 731 are not easily overlapped and short-circuited, which is beneficial to improving the reliability of the battery cell 7, but also the connection strength between the solid electrolyte layer 7314 and the connecting layer 7313 will not be too great, which will make the processing of the pole piece 731 more difficult or more costly.

[0141] Exemplarily, the range of the interlayer peel strength H between the solid electrolyte layer 7314 and the connecting layer 7313 can be set to 7N / m≤H≤10N / m. Exemplarily, the interlayer peel strength H between the solid electrolyte layer 7314 and the connecting layer 7313 can be 7N / m, 8N / m, 9N / m or 10N / m, so that the connection between the solid electrolyte layer 7314 and the connecting layer 7313 is firm, the solid electrolyte layer 7314 is not easy to fall off the connecting layer 7313, and the processing cost of the pole piece 731 is not too high.

[0142] Some embodiments of the present application provide a method for manufacturing a battery cell 7, referring to Fig. 9 The manufacturing method of the battery cell 7 comprises the following steps:

[0143] S1. Provide a housing 71 and a current collector 7311 having an active material layer 7312 on its surface.

[0144] As in the above technical solution, the housing 71 in step S1 is a component for accommodating other components such as the electrode assembly 73 in the battery cell 7. The active material layer 7312 can be formed by coating the active material slurry on the surface of the current collector 7311 through a coating process and drying the active material slurry.

[0145] S2. Coat a connection slurry on the surface of the active material layer 7312 facing away from the current collector 7311 and dry it to form a connection layer 7313 .

[0146] In step S2, the connection slurry is coated on the surface of the active material layer 7312 away from the current collector 7311 through a coating process, so that the connection slurry covers the active material layer 7312. After the connection slurry is dried, the connection slurry will solidify on the surface of the active material layer 7312 away from the current collector 7311 to form a connection layer 7313.

[0147] S3. Processing a groove 73132 in the groove region 73131 on the surface of the connection layer 7313 away from the active material layer 7312 .

[0148] In step S3, the groove area 73131 may be an area divided on the surface of the connection layer 7313 away from the active material layer 7312, and the groove area 73131 may be an area where the corresponding solid electrolyte layer 7314 is prone to failure. Exemplarily, the groove area 73131 may be an area close to two opposite edges of the connection layer 7313 in the first direction X.

[0149] The groove 73132 is machined on the groove area 73131 on the surface of the connection layer 7313 away from the active material layer 7312 by removing material, so that the groove 73132 can accommodate and block the flow of the solid electrolyte slurry.

[0150] S4. Coat the solid electrolyte slurry on the surface of the connection layer 7313 away from the active material layer 7312 and dry it to obtain the electrode 731 with the solid electrolyte layer 7314.

[0151] In step S4, the solid electrolyte slurry is coated on the surface of the connection layer 7313 away from the active material layer 7312, so that the solid electrolyte slurry covers the connection layer 7313, wherein the groove area 73131 is covered by the solid electrolyte slurry. After the solid electrolyte slurry is dried, the solid electrolyte slurry will solidify on the surface of the connection layer 7313 away from the active material layer 7312 to form a solid electrolyte layer 7314, so that the pole piece 731 has a solid electrolyte layer 7314.

[0152] S5, stacking the electrode sheets 731 to form an electrode assembly 73.

[0153] In step S5, the electrode sheets 731 are stacked to form an electrode assembly 73, which may refer to winding the stacked positive electrode sheets 731 and the negative electrode sheets 731 to form an electrode assembly 73 with a wound structure; or it may refer to alternately stacking a plurality of positive electrode sheets 731 and a plurality of negative electrode sheets 731 to form an electrode assembly 73 with a laminated structure.

[0154] S6 , installing the electrode assembly 73 into the housing 71 to form a battery cell 7 .

[0155] In step S6 , the battery cell 7 is formed by installing the electrode assembly 73 into the housing 71 and connecting the tabs of the electrode assembly 73 to the electrode terminals of the housing 71 .

[0156] In some embodiments, the current collector 7311 includes a blank area 73111 and a coating area 73112 arranged along a first direction X, the coating area 73112 is provided with an active material layer 7312, and the blank area 73111 is not provided with an active material layer 7312, the connection layer 7313 includes two end faces arranged opposite to each other along the first direction X, the end faces are connected to the surface of the connection layer 7313 away from the active material layer 7312, and the groove area 73131 includes two sub-areas 73133, and the two sub-areas 73133 are respectively connected to the two end faces. The step of machining the groove 73132 in the groove area 73131 on the surface of the connection layer 7313 away from the active material layer 7312 includes: machining the groove 73132 in the sub-area 73133.

[0157] As described in the above technical solution, the groove area 73131 includes two sub-areas 73133 respectively connected to the two end surfaces, so that the two sub-areas 73133 are areas connected to two opposite edges of the connection layer 7313 in the first direction X.

[0158] By processing the groove 73132 in the sub-area 73133, the groove 73132 is located in the area connected to the two opposite edges of the connecting layer 7313 in the first direction X. When the solid electrolyte slurry is coated on the edge of the connecting layer 7313 in the first direction X, the solid electrolyte slurry will flow into the groove 73132, forming an interlocking force with the connecting layer 7313, thereby reducing the fluidity of the solid electrolyte slurry. The solid electrolyte slurry is not easy to flow from the edge of the connecting layer 7313 in the first direction X to the blank area 73111, which is beneficial to reducing the reduction in the thickness of the solid electrolyte layer 7314 caused by the flow of the solid electrolyte slurry.

[0159] In some embodiments, the groove 73132 is processed by laser engraving or chemical etching.

[0160] The groove 73132 may be formed by laser grooving, which may be performed by using a laser to process the surface of the connection layer 7313 away from the active material layer 7312 to form the groove 73132. The groove 73132 may be formed by chemical etching, which may be performed by using a chemical reagent to corrode the surface of the connection layer 7313 away from the active material layer 7312 to form the groove 73132.

[0161] Some embodiments of the present application further provide a battery device 2, which includes a battery cell 7 provided by the above technical solution.

[0162] Some embodiments of the present application further provide an electrical device, which includes the battery device 2 provided by the above technical solution, and the battery device 2 is used to provide electrical energy.

[0163] Some embodiments of the present application provide a battery cell 7, which includes a shell 71 and an electrode assembly 73, wherein the electrode assembly 73 is arranged in a cavity 72 of the shell 71, and the electrode assembly 73 includes a stacked electrode sheet 731, and the electrode sheet 731 includes a current collector 7311, an active material layer 7312, a connecting layer 7313 and a solid electrolyte layer 7314 which are stacked in sequence, the active material layer 7312 is arranged on the surface of the current collector 7311, the connecting layer 7313 is arranged on the surface of the active material layer 7312 away from the current collector 7311, and the surface of the connecting layer 7313 away from the active material layer 7312 is provided with a groove area 73131 having an inwardly recessed groove 73132. The current collector 7311 includes a blank area 73111 and a coating area 73112 arranged along the first direction X, the coating area 73112 is provided with an active material layer 7312, and the blank area 73111 is not provided with an active material layer 7312, the connecting layer 7313 includes two end faces arranged opposite to each other along the first direction X, the end faces are connected to the surface of the connecting layer 7313 away from the active material layer 7312, the groove area 73131 includes two sub-areas 73133 respectively connected to the two end faces, and the two sub-areas 73133 are arranged at intervals along the first direction X.

[0164] In the above structure, since the surface of the connecting layer 7313 facing away from the active material layer 7312 has a groove area 73131 with a groove 73132, the solid electrolyte layer 7314 is arranged on the surface of the connecting layer 7313 having the groove area 73131, and part of the solid electrolyte layer 7314 enters the groove 73132 and is connected to the inner wall of the groove 73132, not only the solid electrolyte layer 7314 in the groove area 73131 has a larger thickness, but also the solid electrolyte layer 7314 in the groove area 73131 has a larger contact area with the connecting layer 7313, the solid electrolyte layer 7314 is not easy to fall off, reducing the possibility of failure of the solid electrolyte layer 7314 due to its small thickness or falling off, making it difficult for adjacent two pole pieces 731 to overlap and short-circuit, which is beneficial to improving the reliability of the battery cell 7.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A shell, forming a cavity; An electrode assembly is arranged in the cavity, the electrode assembly comprises a stacked electrode sheet, the electrode sheet comprises a current collector, an active material layer, a connecting layer and a solid electrolyte layer, the active material layer is arranged on the surface of the current collector, the connecting layer is arranged on the surface of the active material layer away from the current collector, a groove area is provided on the surface of the connecting layer away from the active material layer, the groove area is provided with an inwardly concave groove, the solid electrolyte layer is arranged on the surface of the connecting layer away from the active material layer and covers the groove area, and a part of the solid electrolyte layer enters the groove and is connected to the inner wall of the groove; The current collector includes a blank area and a coating area arranged along a first direction, the coating area is provided with the active material layer, and the blank area is not provided with the active material layer, the connecting layer includes two end faces arranged opposite to each other along the first direction, the end faces are connected to the surface of the connecting layer away from the active material layer, the groove area includes two sub-areas, the two sub-areas are respectively connected to the two end faces; the two sub-areas are arranged at intervals along the first direction.

2. The battery cell according to claim 1, characterized in that: The sub-region penetrates the connection layer along a second direction, and the second direction is perpendicular to the first direction.

3. The battery cell according to claim 1, characterized in that: The area of ​​the groove region is set to A, the area of ​​the surface of the connecting layer away from the active material layer is set to B, and A / B≥10%.

4. The battery cell according to claim 1, characterized in that: There are a plurality of grooves, and the plurality of grooves are spaced apart along the second direction to form a groove group. There are a plurality of groove groups, and the plurality of groove groups are spaced apart along the first direction, and the second direction is perpendicular to the first direction.

5. The battery cell according to claim 4, characterized in that: The interval between two adjacent grooves in the second direction is set to E, 1μm≤E≤10000μm, and the interval between two adjacent groove groups in the first direction is set to F, 1μm≤F≤10000μm.

6. The battery cell according to claim 4, characterized in that: The cross-sectional shape of the groove is configured to be at least one of a circle or a polygon, and the cross-sectional shape is parallel to a surface of the connection layer facing away from the active material layer.

7. The battery cell according to claim 6, characterized in that: The cross-sectional shape of the groove is configured as a circle, and the diameter of the groove is set to G, 1 μm≤G≤10000 μm.

8. The battery cell according to claim 2, characterized in that: The groove penetrates the connection layer along the second direction, and a plurality of the grooves are provided, and the plurality of the grooves are spaced apart along the first direction.

9. The battery cell according to claim 8, characterized in that: The interval between two adjacent grooves in the first direction is set to D, 1 μm≤D≤10000 μm.

10. The battery cell according to claim 1, characterized in that: The grooves are formed by laser engraving or chemical etching.

11. The battery cell according to claim 1, characterized in that: Along the thickness direction of the connection layer, the size of the groove is set to C, 1 μm≤C≤2000 μm.

12. The battery cell according to claim 11, characterized in that: 5μm≤C≤500μm.

13. The battery cell according to claim 1, characterized in that: The interlayer peeling strength between the solid electrolyte layer and the connecting layer is set to H, 5N / m≤H≤10N / m.

14. A method for manufacturing a battery cell, characterized in that: For manufacturing a battery cell as claimed in any one of claims 1 to 13, the manufacturing method of the battery cell comprises: Providing a shell and a current collector with an active material layer on the surface; Coating a connection slurry on the surface of the active material layer away from the current collector and drying it to form a connection layer; Processing the groove in a groove area on a surface of the connecting layer away from the active material layer; Coating a solid electrolyte slurry on the surface of the connection layer away from the active material layer and drying it to obtain a pole piece with a solid electrolyte layer; The electrode sheets are stacked to form an electrode assembly; The electrode assembly is housed in the housing and forms a battery cell.

15. The method for manufacturing a battery cell according to claim 14, characterized in that: The current collector comprises a blank area and a coating area arranged along a first direction, the coating area is provided with the active material layer, and the blank area is not provided with the active material layer, the connecting layer comprises two end surfaces arranged opposite to each other along the first direction, the end surfaces are connected to a surface of the connecting layer away from the active material layer, the groove area comprises two sub-areas, the two sub-areas are respectively connected to the two end surfaces, and the step of machining and forming a groove in the groove area on the surface of the connecting layer away from the active material layer comprises: The groove is machined in the sub-area.

16. The method for manufacturing a battery cell according to claim 14, characterized in that: The groove is processed by laser grooving or chemical etching.

17. A battery device, characterized in that: Comprising a battery cell as claimed in any one of claims 1 to 13.

18. An electrical device, characterized in that: Comprising the battery device as claimed in claim 17, the battery device is used to provide electrical energy.

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