Battery cell, battery device, and electric device

Abstract

The application belongs to the technical field of batteries, and provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a positive electrode sheet, an electrolyte layer and a negative electrode sheet which are stacked, the electrolyte layer and the negative electrode sheet form a combined structure, at least part of the combined structure exceeds the positive electrode sheet, one side of the electrolyte layer facing the positive electrode sheet is provided with a groove, at least part of the side wall of the groove is a slope, the area of the cross section of the groove decreases from the groove opening to the groove bottom, part of the positive electrode sheet is arranged in the groove, and the shape of the part of the positive electrode sheet in the groove is matched with the shape of the groove. The battery monomer, the battery device and the power utilization device provided by the application can reduce the risk of cracks or breakage of the negative electrode sheet and the electrolyte layer.

Description

Technical Field

[0001] This application belongs to the field of battery technology, and in particular relates to a battery cell, a battery device, and an electrical device. Background Technology

[0002] In the fabrication of all-solid-state batteries, the positive electrode, electrolyte layer, and negative electrode are first prepared separately. These are then assembled using a stacking method. After stacking, the electrodes are pressed into a dense structure through warm isostatic pressing (WIP) to improve the contact tightness between the electrodes and the electrolyte layer, as well as the mechanical properties of the electrode components in the battery. However, during WIP, cracks or even fractures may occur between the portion of the negative electrode and electrolyte layer that extends beyond the positive electrode and other parts, affecting the manufacturing quality and reliability of the battery cell. Utility Model Content

[0003] In view of the above problems, this application provides a battery cell, a battery device and an electrical device, which aims to reduce the risk of cracks or fractures in the negative electrode and electrolyte layer.

[0004] In a first aspect, embodiments of this application provide a battery cell including a positive electrode, an electrolyte layer, and a negative electrode stacked together. The electrolyte layer and the negative electrode form a combined structure, at least a portion of which extends beyond the positive electrode. A groove is provided on the side of the electrolyte layer facing the positive electrode. At least a portion of the sidewall of the groove is inclined. The cross-sectional area of ​​the groove decreases from the groove opening to the groove bottom. A portion of the positive electrode is disposed within the groove, and the shape of the portion of the positive electrode located within the groove is adapted to the shape of the groove.

[0005] The battery cell has a groove on the side of the electrolyte layer facing the positive electrode, and at least part of the sidewall of the groove is inclined. The cross-sectional area of ​​the groove decreases from the groove opening to the bottom. The shape of the part of the positive electrode located in the groove is adapted to the shape of the groove, so that the contact form between the edge of the positive electrode and the electrolyte changes from line contact to surface contact. This reduces the force of the positive electrode on the electrolyte during static pressure, and reduces the risk of cracking or breaking of the electrolyte layer and the combined structure of the electrolyte layer and the negative electrode under the action of the positive electrode. This can reduce the risk of short circuit when the positive and negative electrodes come into contact.

[0006] In some possible implementations of the first aspect, the groove has a bottom wall connected to the sidewalls. This ensures that the bottom of the groove and the bottom wall of the positive electrode do not have sharp points, reducing the risk of cracking or breakage of the electrolyte layer and the combined structure of the electrolyte layer and the negative electrode under the action of the positive electrode during the temperature isostatic pressing process, thereby reducing the risk of short circuits occurring at the contact between the positive and negative electrodes.

[0007] In some possible implementations of the first aspect, multiple sidewalls are provided, with the multiple sidewalls connected end to end, and at least a portion of each sidewall is a slope. This allows each edge of the positive electrode to make surface contact with the electrolyte layer, reducing the risk of cracking or breakage of the electrolyte layer and the combined structure of the electrolyte layer and the negative electrode under the action of the positive electrode during the temperature isostatic pressing process, thereby reducing the risk of short circuits occurring at the contact between the positive and negative electrodes.

[0008] In some possible implementations of the first aspect, the electrolyte layer has a length direction and a width direction, and the sidewalls of the groove include a first sidewall, a second sidewall, a third sidewall and a fourth sidewall connected in sequence. The length directions of the first sidewall and the third sidewall both extend along the width direction of the electrolyte layer, and the length directions of the second sidewall and the fourth sidewall both extend along the length direction of the electrolyte layer. The first sidewall, the second sidewall, the third sidewall and the fourth sidewall are at least partially inclined surfaces.

[0009] The positive electrode sheet generally also adopts a cubic structure. That is, the positive electrode sheet generally has a length direction and a width direction. Furthermore, the length direction of the positive electrode sheet is generally parallel to the length direction of the electrolyte layer, and the width direction of the positive electrode sheet is generally parallel to the width direction of the electrolyte layer. Based on the above reasons, using the solution provided in this embodiment, the portion of the positive electrode sheet located within the groove can be obtained by removing the corner portion corresponding to the edge of the positive electrode sheet in contact with the electrolyte layer, which facilitates design and fabrication; and it can reduce the pressure on the electrolyte layer from different edges of the positive electrode sheet, thereby reducing the risk of cracks or fractures in different areas of the electrolyte layer.

[0010] In some possible implementations of the first aspect, the inclined planes corresponding to the first sidewall and the third sidewall have the same inclination angle, and the inclined planes corresponding to the second sidewall and the fourth sidewall have the same inclination angle.

[0011] This allows at least some parameters of the first and third sidewalls to be identical, and at least some parameters of the second and fourth sidewalls to be identical, which facilitates design and fabrication.

[0012] In some possible implementations of the first aspect, the positive electrode includes a current collector and an active material layer, the active material layer having a first surface and a second surface disposed opposite to each other in the thickness direction, the first surface being connected to the current collector, the second surface being in contact with the bottom wall of the groove, and the area of ​​the second surface being 95%-100% of the area of ​​the first surface.

[0013] This ensures that the area of ​​the second side is not much different from that of the first side, so that the electrochemical reaction of the battery cell is less affected by the groove design.

[0014] In some possible implementations of the first aspect, the area of ​​the second surface is 99%-100% of the area of ​​the first surface.

[0015] This makes the area of ​​the second side less different from that of the first side, so that the electrochemical reaction of the battery cell is less affected by the groove design.

[0016] In some possible implementations of the first aspect, the depth of the groove is less than or equal to half the thickness of the electrolyte layer.

[0017] This allows the grooves to disperse the shear stress exerted by the positive electrode on the electrolyte layer to a certain extent.

[0018] In some possible implementations of the first aspect, the depth of the groove is greater than or equal to 1 / 3 of the thickness of the electrolyte layer.

[0019] This allows the groove to effectively disperse the shear stress exerted by the positive electrode on the electrolyte layer. When the depth of the groove is within a reasonable range, such as when the depth of the groove is equal to 1 / 3 of the thickness of the electrolyte layer, the mechanical strength of the electrolyte layer can meet the usage requirements, and the electrolyte layer can also meet the electrochemical performance requirements of the battery cell.

[0020] In some possible implementations of the first aspect, at least one apex corner of the groove is rounded.

[0021] This can further reduce stress concentration.

[0022] In some possible implementations of the first aspect, the inclination angle of the inclined plane is 40°-60°, which is the angle between the inclined plane and the thickness direction of the electrolyte layer.

[0023] The inclined angle of the slope adopts the solution provided in this embodiment. In most cases, it can make the electrolyte layer less prone to cracking or breakage during preparation, and the above-mentioned inclined angle is easy to process.

[0024] In some possible implementations of the first aspect, the inclination angle of the inclined plane is 45°.

[0025] The tilt angle of the slope adopts the solution provided in this embodiment, which makes it less likely for cracks or breaks to occur in the electrolyte layer during preparation, and the above-mentioned tilt angle is convenient for design and processing.

[0026] Secondly, embodiments of this application provide a battery device, including a battery cell provided by any of the above solutions.

[0027] Thirdly, embodiments of this application provide an electrical device, including a battery cell or battery device provided by any of the above solutions.

[0028] The effect of the second aspect is the same as that of the first aspect, so it will not be repeated here.

[0029] 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

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0031] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0032] Figure 2 This is an exploded view of the battery device provided in some embodiments of this application;

[0033] Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application;

[0034] Figure 4 This is a schematic diagram of the combined structure of the electrode and electrolyte layer in a battery cell provided in some embodiments of this application;

[0035] Figure 5 This is an exploded structural diagram of the combined structure of the positive electrode and electrolyte layer in a battery cell provided in some embodiments of this application;

[0036] Figure 6 This is a schematic diagram of the combined structure of the positive electrode and electrolyte layer in a battery cell provided in some embodiments of this application;

[0037] Figure 7 For along Figure 6 Schematic diagram of the cross-sectional structure along line AA;

[0038] Figure 8 For along Figure 6 Schematic diagram of the cross-sectional structure of the middle BB line.

[0039] The reference numerals in the detailed embodiments are as follows:

[0040] 1000, vehicles;

[0041] 100. Battery assembly; 200. Controller; 300. Motor;

[0042] 10. Housing; 11. Cover; 12. Tray; 20. Battery cell; 21. End cap; 22. Shell; 23. Electrode assembly; 231. Main body; 232. Tab; 24. Positive electrode; 25. Electrolyte layer; 26. Negative electrode; 27. Groove; 271. Sloping surface; 272. Bottom wall; 273. First side wall; 274. Second side wall; 275. Third side wall; 276. Fourth side wall; 241. Current collector; 242. Active material layer; 242a. First surface; 242b. Second surface;

[0043] X: length direction; Y: width direction; Z: thickness direction. Detailed Implementation

[0044] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In this document, the term "embodiment" means that a particular 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 separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0049] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0050] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0051] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0052] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0053] An all-solid-state battery (ASSB) is a rechargeable battery that uses a solid electrolyte layer (containing no liquid or gel components). Its core characteristic is that both the electrodes (positive and negative) and the electrolyte layer are solid materials. In the fabrication of an all-solid-state battery, the positive electrode, electrolyte layer, and negative electrode are first prepared separately. These are then assembled using a stacking method. After stacking, a dense structure is formed through warm isostatic pressing (WIP) to improve the contact tightness between the electrodes and the electrolyte layer and the mechanical properties of the electrode components in the battery. The size of the positive electrode is generally smaller than the size of the electrolyte layer and the negative electrode; that is, at least a portion of the electrolyte layer and the negative electrode extends beyond the positive electrode. Since the edge of the positive electrode contacts the electrolyte layer via line contact, during WIP, the vertical pressure on the edge of the positive electrode acts on the portions of the electrolyte layer and the negative electrode that extend beyond the positive electrode. This can easily lead to a significant increase in shear stress in these extended portions, i.e., shear stress concentration. Due to shear stress concentration, cracks or even fractures may occur between the portion of the negative electrode and electrolyte layer that extends beyond the positive electrode and other parts. The fractured portion of the electrolyte layer and negative electrode will not move downwards or compress under the pressure of the positive electrode. This could cause the fractured portion of the negative electrode to overlap with the positive electrode, leading to an internal short circuit within the battery cell and affecting the manufacturing quality and reliability of the battery cell.

[0054] This problem is particularly prominent in high-energy-density battery cells. This is because the electrode thickness and dimensions of high-energy-density battery cells are designed to be more compact, making the aforementioned shear stress concentration phenomenon more likely to occur.

[0055] To address the aforementioned issues, this application provides a single battery cell. This battery cell has a groove formed on the side of the electrolyte layer facing the positive electrode, with at least a portion of the groove's sidewalls being inclined. The cross-sectional area of ​​the groove decreases from the opening to the bottom. The shape of the portion of the positive electrode located within the groove is adapted to the shape of the groove, changing the contact between the edge of the positive electrode and the electrolyte from line contact to surface contact. This reduces the force exerted by the positive electrode on the electrolyte during static pressure testing, lowering the risk of cracks or fractures in the electrolyte layer and the combined structure of the electrolyte layer and the negative electrode under the influence of the positive electrode. This, in turn, reduces the risk of short circuits occurring at the contact between the positive and negative electrodes.

[0056] The battery cells disclosed in this application can be used in battery devices and electrical devices that use the battery cells as a power source, or in various energy storage devices, energy storage systems, and charging networks that use batteries as energy storage elements. Electrical devices can be, but are 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.

[0057] 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.

[0058] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 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. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is provided 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 starting, navigation, and driving.

[0059] 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.

[0060] Please refer to Figure 2 , Figure 2 This is an exploded structural diagram of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10.

[0061] The housing 10 provides a storage space for the battery cells 20, and can adopt various structures. In some embodiments, the housing 10 may include a cover 11 and a tray 12. The cover 11 covers the tray, and together with the tray 12, defines a storage space for accommodating the battery cells 20. The tray 12 may be a hollow structure with one open end, and the cover 11 may be a plate-like structure, covering the open side of the tray 12 so that the cover 11 and the tray 12 together define the storage space; the cover 11 and the tray 12 may also be hollow structures with side openings, with the open side of the cover 11 covering the open side of the tray 12. Of course, the housing 10 formed by the cover 11 and the tray 12 can be of various shapes, such as a circular through-hole, a cuboid, etc. The tray 12 is an important structural support component in the battery system, used to store and protect the battery cells, and also has a significant impact on the collision safety of the vehicle and the overall torsional and bending stiffness of the vehicle body.

[0062] Multiple battery cells 20 can be provided, and these cells can be connected in series, parallel, or mixed connection via a busbar. Mixed connection refers to a configuration where multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or mixed connection, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or mixed connection to form a battery module, and then multiple battery modules connected in series, parallel, or mixed connection to form a whole, housed within the housing 10. The battery device 100 may also include other structures; for example, it may include a busbar for electrical connection between the multiple battery cells 20. As an example, multiple battery cells 20 can form a battery module, which is an independent module formed by arranging and fixing multiple battery cells 20. As an example, a battery module can be formed by binding multiple battery cells 20 together with cable ties.

[0063] Each battery cell 20 can be a secondary battery or a primary battery. A secondary battery refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell 20 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment is not limited to this. The battery cell can have a circular through-body, a flat body, a cuboid, or other shapes.

[0064] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell 20 provided in some embodiments of this application. The battery cell 20 refers to the smallest unit that makes up a battery. Figure 3The battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

[0065] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved safety performance. Functional components such as electrode terminals can be provided on end cap 21. Electrode terminals can be used for electrical connection with electrode assembly 23 for outputting or inputting electrical energy into battery cell 20. In some embodiments, end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0066] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, circular through-hole, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.

[0067] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by stacking positive and negative electrode plates, and typically a separator is provided between the positive and negative electrode plates. The portions of the positive and negative electrode plates containing active material constitute the main body 231 of the electrode assembly 23, while the portions of the positive and negative electrode plates without active material each constitute a tab 232. The positive and negative tabs may be located together at one end of the main body 231 or separately at both ends of the main body 231. During the charging and discharging process of the battery cell 20, the positive and negative active materials react with the electrolyte, and the tabs 232 connect to the electrode terminals to form a current loop.

[0068] Figure 4 This is a schematic diagram of the combined structure of the electrode and electrolyte layer in a battery cell provided in some embodiments of this application. Figure 5 This is an exploded structural diagram of the combined structure of the positive electrode and electrolyte layer in a battery cell provided in some embodiments of this application. Figure 6 This is a schematic diagram of the combined structure of the positive electrode and electrolyte layer in a battery cell provided in some embodiments of this application. Figure 7 For along Figure 6 A schematic diagram of the cross-sectional structure along line AA. It should be noted that... Figure 7 The arrow in the electrolyte layer indicates the direction of the electric field lines between the positive electrode and the electrolyte layer when the battery device is powered on.

[0069] Please refer to Figures 4 to 7 This application provides a battery cell 20. The battery cell 20 includes a positive electrode 24, an electrolyte layer 25, and a negative electrode 26 stacked together. The electrolyte layer 25 and the negative electrode 26 form a combined structure. At least a portion of the combined structure extends beyond the positive electrode 24. A groove 27 is provided on the side of the electrolyte layer 25 facing the positive electrode 24. At least a portion of the sidewall of the groove 27 is an inclined surface 271. The cross-sectional area of ​​the groove 27 decreases from the groove opening to the bottom. A portion of the positive electrode 24 is disposed within the groove 27. The shape of the portion of the positive electrode 24 located within the groove 27 is adapted to the shape of the groove 27.

[0070] Generally, an electrolyte layer 25 is provided on both sides of any positive electrode 24 and any negative electrode 26, and adjacent positive electrode 24 and negative electrode 26 are separated by the electrolyte layer 25. The combined structure formed by the electrolyte layer 25 and the negative electrode 26 generally extends beyond the positive electrode 24 in any direction. In special cases, the combined structure may extend beyond the positive electrode 24 in one or more directions, depending on the application requirements.

[0071] A groove 27 is provided on the side of the electrolyte layer 25 facing the positive electrode plate 24. The groove 27 can be integrally formed on the electrolyte layer 25 during its fabrication, or it can be formed by cutting or other methods after the electrolyte layer 25 is fabricated. The groove 27 is generally formed by at least one sidewall, or it can be formed by at least one sidewall and a bottom wall 272, depending on the application requirements. The bottom wall 272 is the surface of the inner wall of the groove 27 perpendicular to the thickness direction of the electrolyte, and the sidewalls are the surfaces of the inner wall of the groove 27 perpendicular to the thickness direction of the electrolyte or forming other angles.

[0072] The fact that at least part of the sidewall of the groove 27 is inclined surface 271 means that when the groove 27 has multiple sidewalls, some sidewalls can be inclined surface 271 and the other part can be perpendicular to the thickness direction of the electrolyte. Alternatively, the part of each sidewall near the bottom wall 272 can be inclined surface 271 and the part near the groove opening can be perpendicular to the thickness direction of the electrolyte. Or it can be a curved surface, or other settings can be adopted. The specific settings can be set according to the usage requirements.

[0073] The cross-section of groove 27 refers to the section obtained by cutting groove 27 with a plane perpendicular to its depth direction (which is also the thickness direction of the electrolyte). The groove opening is the opening of groove 27, and the groove bottom is the bottom wall 272 of groove 27 or a point within groove 27 opposite to the groove opening. For example, when groove 27 is frustum-shaped, it has a bottom wall 272, and the groove bottom is the bottom wall 272 of groove 27. When groove 27 has a conical structure, it does not have a bottom wall 272, and the groove bottom is the vertex of the apex formed by several side walls within groove 27, which is also the point opposite to the groove opening.

[0074] The positive electrode 24 generally has a current collector 241 and an active layer, and generally only a part of the active layer is located in the groove 27.

[0075] The shape of the part of the positive electrode 24 located in the groove 27 is adapted to the shape of the groove 27, which means that the shape of the part of the positive electrode 24 located in the groove 27 is roughly the same as the shape of the groove 27, and the positive electrode 24 and the groove 27 are spaced apart.

[0076] The stress analysis of the battery cell 20 provided in the embodiments of this application is as follows:

[0077] The positive electrode 24, electrolyte layer 25, and negative electrode 26 are stacked sequentially, and then pressure is applied to the positive electrode 24, electrolyte layer 25, and negative electrode 26. After receiving the pressure, the positive electrode 24 moves toward the electrolyte layer 25. The contact area between the edge of the positive electrode 24 and the electrolyte is no longer a straight line, but at least partially becomes a surface contact between the inclined surface 271 of the groove 27 and the surface of the inclined surface 271. This changes the pressure applied by the edge of the positive electrode 24 to the electrolyte layer 25 from the pressure it receives itself to a component force perpendicular to the inclined surface 271 and a component force parallel to the inclined surface 271, and these components are all less than the aforementioned pressure.

[0078] For example, if the pressure on the electrolyte layer 25 during preparation is P, and the angle between the inclined plane 271 and the thickness direction Z is θ1.

[0079] Along the width Y direction of the electrolyte layer 25, the pressure P is decomposed into a component force P1 perpendicular to the inclined plane 271 and a component force P2 parallel to the inclined plane 271:

[0080] P1=P*cosθ1; P2=P*sinθ1.

[0081] Among them, θ1 is greater than 0° and less than 90°, and P1 and P2 are both less than P.

[0082] This reduces the risk of cracking or breaking of the electrolyte layer 25 and the combined structure of the electrolyte layer 25 and the negative electrode 26 under the action of the positive electrode 24, thereby reducing the risk of short circuit when the positive electrode 24 and the negative electrode 26 come into contact.

[0083] Therefore, the battery cell 20 provided in this application embodiment has a groove 27 on the side of the electrolyte layer 25 facing the positive electrode 24, and at least part of the sidewall of the groove 27 is an inclined surface 271. The cross-sectional area of ​​the groove 27 decreases from the groove opening to the groove bottom. The shape of the part of the positive electrode 24 located in the groove 27 is adapted to the shape of the groove 27, so that the contact form between the edge of the positive electrode 24 and the electrolyte changes from line contact to surface contact. It also reduces the force of the positive electrode 24 on the electrolyte during static pressure, and reduces the risk of cracking or breaking of the electrolyte layer 25 and the combined structure composed of the electrolyte layer 25 and the negative electrode 26 under the action of the positive electrode 24. This can reduce the risk of short circuit when the positive electrode 24 and the negative electrode 26 come into contact.

[0084] like Figure 5 As shown, in some embodiments, the groove 27 has a bottom wall 272 connected to the side wall.

[0085] This ensures that the bottom of the groove 27 and the bottom wall 272 of the positive electrode 24 do not have sharp points, which can reduce the risk of cracking or breaking of the electrolyte layer 25 and the combined structure of the electrolyte layer 25 and the negative electrode 26 under the action of the positive electrode 24 during the temperature isostatic pressing process, thereby reducing the risk of short circuit when the positive electrode 24 and the negative electrode 26 come into contact.

[0086] In some embodiments, multiple sidewalls are provided. The multiple sidewalls are connected end to end. At least a portion of each sidewall is an inclined surface 271.

[0087] This allows each edge of the positive electrode 24 to make surface contact with the electrolyte layer 25, which reduces the risk of cracking or breaking of the electrolyte layer 25 and the combined structure of the electrolyte layer 25 and the negative electrode 26 under the action of the positive electrode 24 during the temperature isostatic pressing process. This reduces the risk of short circuits occurring when the positive electrode 24 and the negative electrode 26 come into contact.

[0088] like Figure 5 As shown, in some embodiments, the electrolyte layer 25 has a length direction X and a width direction Y. The sidewalls of the groove 27 include a first sidewall 273, a second sidewall 274, a third sidewall 275, and a fourth sidewall 276 connected in sequence. The length direction X of the first sidewall 273 and the third sidewall 275 extends along the width direction Y of the electrolyte layer 25. The length direction X of the second sidewall 274 and the fourth sidewall 276 extends along the length direction X of the electrolyte layer 25. The first sidewall 273, the second sidewall 274, the third sidewall 275, and the fourth sidewall 276 are all at least partially sloped surfaces 271.

[0089] The electrolyte layer 25 is generally a cubic structure. The longitudinal direction of the electrolyte layer 25 refers to the direction with the largest dimension. The width direction Y of the electrolyte layer 25 refers to the direction perpendicular to both the longitudinal direction X and the thickness direction.

[0090] The positive electrode 24 generally also adopts a cubic structure. That is, the positive electrode 24 generally has a length direction X and a width direction Y. Moreover, the length direction X of the positive electrode 24 is generally parallel to the length direction X of the electrolyte layer 25, and the width direction Y of the positive electrode 24 is generally parallel to the width direction Y of the electrolyte layer 25.

[0091] In this embodiment, the sidewalls of the groove 27 may include only the first sidewall 273, the second sidewall 274, the third sidewall 275, and the fourth sidewall 276, or may include other sidewalls in addition to the first sidewall 273, the second sidewall 274, the third sidewall 275, and the fourth sidewall 276, depending on the usage requirements.

[0092] The length direction X of both the first sidewall 273 and the third sidewall 275 extends along the width direction Y of the electrolyte layer 25, meaning that the direction in which the longest dimension of the first sidewall 273 is parallel to the width direction Y of the electrolyte layer 25, and the direction in which the longest dimension of the third sidewall 275 is parallel to the width direction Y of the electrolyte layer 25. Similarly, the length direction X of both the second sidewall 274 and the fourth sidewall 276 extends along the length direction X of the electrolyte layer 25, meaning that the direction in which the longest dimension of the second sidewall 274 is parallel to the length direction X of the electrolyte layer 25, and the direction in which the longest dimension of the fourth sidewall 276 is parallel to the length direction X of the electrolyte layer 25.

[0093] The first sidewall 273, the second sidewall 274, the third sidewall 275, and the fourth sidewall 276 are all at least partially inclined surfaces 271, meaning that at least a portion of the first sidewall 273 is an inclined surface 271, at least a portion of the second sidewall 274 is an inclined surface 271, at least a portion of the third sidewall 275 is an inclined surface 271, and at least a portion of the fourth sidewall 276 is an inclined surface 271.

[0094] The positive electrode 24 generally also adopts a cubic structure. That is, the positive electrode 24 generally has a length direction X and a width direction Y. Moreover, the length direction X of the positive electrode 24 is generally parallel to the length direction X of the electrolyte layer 25, and the width direction Y of the positive electrode 24 is generally parallel to the width direction Y of the electrolyte layer 25. Based on the above reasons, using the solution provided in this embodiment, the portion of the positive electrode 24 located in the groove 27 can be obtained by removing the corner portion corresponding to the edge of the positive electrode 24 that contacts the electrolyte layer 25, which is convenient for design and fabrication; and it can reduce the pressure of different edges of the positive electrode 24 on the electrolyte layer 25, which can reduce the risk of cracks or fractures in different areas of the electrolyte layer 25.

[0095] like Figure 7 As shown, in some embodiments, the inclined surfaces 271 corresponding to the first sidewall 273 and the inclined surfaces 271 corresponding to the third sidewall 275 have the same inclination angle, and the inclined surfaces 271 corresponding to the second sidewall 274 and the inclined surfaces 271 corresponding to the fourth sidewall 276 have the same inclination angle.

[0096] The inclined planes 271 corresponding to the first sidewall 273 and the third sidewall 275 have the same inclination angle, meaning that the angle between the inclined plane 271 corresponding to the first sidewall 273 and the thickness direction of the electrolyte layer 25 is the same as the angle between the inclined plane 271 corresponding to the third sidewall 275 and the thickness direction of the electrolyte layer 25. Similarly, the inclined planes 271 corresponding to the second sidewall 274 and the fourth sidewall 276 have the same inclination angle, meaning that the angle between the inclined plane 271 corresponding to the second sidewall 274 and the thickness direction of the electrolyte layer 25 is the same as the angle between the inclined plane 271 corresponding to the fourth sidewall 276 and the thickness direction of the electrolyte layer 25.

[0097] This allows at least some parameters of the first sidewall 273 and the third sidewall 275 to be identical, and at least some parameters of the second sidewall 274 and the fourth sidewall 276 to be identical, which facilitates design and fabrication.

[0098] like Figure 7 As shown, in some embodiments, the positive electrode 24 includes a current collector 241 and an active material layer 242. The active material layer 242 has a first surface 242a and a second surface 242b disposed opposite to each other in the thickness direction. The first surface 242a is connected to the current collector 241. The second surface 242b is in contact with the bottom wall 272 of the groove 27. The area of ​​the second surface 242b is 95%-100% of the area of ​​the first surface 242a.

[0099] This makes the area of ​​the second surface 242b not much different from that of the first surface 242a, so that the electrochemical reaction of the battery cell 20 is less affected by the design of the groove 27.

[0100] In some embodiments, the area of ​​the second surface 242b is 99%-100% of the area of ​​the first surface 242a.

[0101] This makes the area of ​​the second surface 242b smaller than that of the first surface 242a, so that the electrochemical reaction of the battery cell 20 is less affected by the design of the groove 27.

[0102] In some embodiments, the depth of the groove 27 is less than or equal to half the thickness of the electrolyte layer 25.

[0103] In this embodiment, the depth direction of the groove 27 is the same as the thickness direction of the electrolyte layer 25, i.e., the Z direction in the figure. The depth of the groove 27 refers to the dimension of the groove 27 in the depth direction Z. The thickness of the electrolyte layer 25 refers to the dimension of the electrolyte layer 25 in the thickness direction Z.

[0104] This allows the groove 27 to disperse the shear stress of the positive electrode 24 on the electrolyte layer 25 to a certain extent.

[0105] In some embodiments, the depth of the groove 27 is less than or equal to one-third of the thickness of the electrolyte layer 25.

[0106] This allows the groove 27 to effectively disperse the shear stress exerted by the positive electrode 24 on the electrolyte layer 25. When the depth of the groove 27 is within a reasonable range, such as when the depth of the groove 27 is equal to 1 / 3 of the thickness of the electrolyte layer 25, the mechanical strength of the electrolyte layer 25 can meet the usage requirements, and the electrolyte layer 25 can meet the electrochemical performance requirements of the battery cell 20.

[0107] In some embodiments, at least one apex corner of the groove 27 is rounded.

[0108] Rounded corners refer to the rounded corners formed by smoothly transitioning the sharp or angular corners of a geometric shape (such as a rectangle or polygon) with a circular arc.

[0109] At least one apex corner of the groove 27 is rounded, which can further reduce stress concentration.

[0110] like Figure 7 and Figure 8 As shown, in some embodiments, the inclination angle θ1 or θ2 of the inclined surface 271 is 40°-60°. The inclination angle is the angle between the inclined surface 271 and the thickness direction of the electrolyte layer 25.

[0111] In this embodiment, the inclination angle θ1 or θ2 of each inclined plane 271 can be 40°, 45°, 50°, 55°, 60°, etc., and can be determined according to the usage requirements.

[0112] The tilt angle θ1 or θ2 of the inclined surface 271 adopts the solution provided in this embodiment. In most cases, it can make the electrolyte layer 25 less prone to cracking or breakage during preparation, and the above-mentioned tilt angle is easy to process.

[0113] In some embodiments, the inclination angle θ1 or θ2 of the inclined plane 271 is 45°.

[0114] The tilt angle of the inclined surface 271 adopts the solution provided in this embodiment, which makes it less likely for cracks or breaks to occur in the electrolyte layer 25 during preparation, and the above-mentioned tilt angle is convenient for design and processing.

[0115] In some embodiments, the width of the sidewall of the groove 27 is equal to the depth of the groove 27.

[0116] The width of the sidewall of groove 27 refers to the dimension of the sidewall of groove 27 in the Y direction, which is perpendicular to its own length direction X and the depth direction Z of groove 27.

[0117] The depth of groove 27 refers to the dimension of groove 27 in the depth direction Z.

[0118] The width of the sidewall of groove 27 is equal to the depth of groove 27, which facilitates design and manufacturing.

[0119] According to some embodiments of this application, this application also provides a battery device, including a battery cell provided by any of the above solutions. The battery cell is used to store or provide electrical energy.

[0120] The battery device provided in this application embodiment includes the above-mentioned battery cell and can achieve the same effect, which will not be described in detail here.

[0121] According to some embodiments of this application, this application also provides an electrical device, including a battery cell or battery device provided by any of the above solutions. The battery cell or battery device is used to store or provide electrical energy.

[0122] The electrical device can be any of the aforementioned battery-powered devices or systems.

[0123] The electrical device provided in this application embodiment includes the above-mentioned battery cell or battery device, and can achieve the same effect, which will not be described in detail here.

[0124] like Figures 3 to 8 As shown, one embodiment of this application provides a battery cell 20. The battery cell 20 includes a positive electrode 24, an electrolyte layer 25, and a negative electrode 26 stacked together. The electrolyte layer 25 and the negative electrode 26 form a combined structure. At least a portion of the combined structure extends beyond the positive electrode 24. A groove 27 is provided on the side of the electrolyte layer 25 facing the positive electrode 24. At least a portion of the sidewall of the groove 27 is an inclined surface 271. The cross-sectional area of ​​the groove 27 decreases from the groove opening to the bottom. A portion of the positive electrode 24 is disposed within the groove 27. The shape of the portion of the positive electrode 24 located within the groove 27 is adapted to the shape of the groove 27. During fabrication, the active material layer 242 of the positive electrode 24 can be directly prepared within the groove 27 by coating or other methods.

[0125] The groove 27 has a bottom wall 272, which is connected to the side wall.

[0126] The electrolyte layer 25 has a length direction X and a width direction Y. The sidewalls of the groove 27 include a first sidewall 273, a second sidewall 274, a third sidewall 275, and a fourth sidewall 276 connected in sequence. The length direction X of the first sidewall 273 and the third sidewall 275 extends along the width direction Y of the electrolyte layer 25. The length direction X of the second sidewall 274 and the fourth sidewall 276 extends along the length direction X of the electrolyte layer 25. The first sidewall 273, the second sidewall 274, the third sidewall 275, and the fourth sidewall 276 are all inclined surfaces 271. The first sidewall 273 and the third sidewall 275 have the same inclination angle. The second sidewall 274 and the fourth sidewall 276 have the same inclination angle.

[0127] The inclination angles of the first sidewall 273 and the third sidewall 275 are denoted as θ1, and the inclination angles of the second sidewall 274 and the fourth sidewall 276 are denoted as θ2.

[0128] θ1=tan -1 (L2 / H1); θ2=tan -1 (T2 / H1).

[0129] Wherein, H1 is the depth of the groove 27, L2 is the dimension of the first sidewall 273 and the third sidewall 275 in the length direction X of the electrolyte layer 25, and T2 is the dimension of the second sidewall 274 and the fourth sidewall 276 in the width direction Y of the electrolyte layer 25.

[0130] The electrolyte layer 25 is subjected to a pressure of P during preparation.

[0131] Along the width Y direction of the electrolyte layer 25, the pressure is decomposed into a component force P1 perpendicular to the first sidewall 273 or the third sidewall 275, and a component force P2 parallel to the first sidewall 273 or the third sidewall 275:

[0132] P1=P*cosθ1; P2=P*sinθ1.

[0133] Along the length X of the electrolyte layer 25, the pressure is decomposed into a component force P3 perpendicular to the second sidewall 274 or the fourth sidewall 276, and a component force P4 parallel to the second sidewall 274 or the fourth sidewall 276:

[0134] P3=P*cosθ2; P4=P*sinθ2.

[0135] The yield strength of the positive electrode 24 is σ1, the yield strength of the electrolyte layer 25 is σ2, and the dimensions of the groove 27 satisfy the following conditions:

[0136] max(P1, P2, P3, P4)≤min(σ1, σ2);

[0137] By adopting the solution provided in this embodiment, any component force of the positive electrode 24 acting on any inclined surface 271 of the electrolyte layer 25 is less than the yield strength of the electrolyte layer 25 and the positive electrode 24. This can reduce the risk of cracks or fractures in the electrolyte layer 25 and the positive electrode 24 during the warm isostatic pressing process, thereby reducing the risk of short circuits occurring when the positive electrode 24 and the negative electrode 26 come into contact.

[0138] The groove 27 mentioned above can be made by processes such as laser cleaning, and the groove 27 can be set to any shape according to the needs of use.

[0139] The solution provided in this embodiment adjusts the stress distribution of the portion of the electrolyte layer 25 that extends beyond the positive electrode 24 through the design of the groove 27, avoiding stress concentration. Furthermore, by selecting suitable materials, the mechanical stability of the combined structure of the electrode and electrolyte layer 25 can be improved, and the electrode coating and electrolyte layer 25 preparation process can be optimized to match the structure of the combined structure of the negative electrode 26 and electrolyte layer 25.

[0140] The solution provided in this embodiment, through the design of the inclined surface 271 of the groove 27, decomposes the vertical shear force into two components along the inclined surface 271, thereby reducing stress concentration and preventing edge breakage of the electrolyte layer 25 and the negative electrode 26. Furthermore, by optimizing the geometry of the groove 27, the stress dispersion effect can be ensured. These features work together to ensure that the electrode assembly 23 composed of the electrode and the electrolyte layer 25 maintains structural integrity during the warm isostatic pressing process, avoiding short circuits caused by overlaps.

[0141] The positive electrode 24 includes a current collector 241 and an active material layer 242. The current collector 241 may include a substrate and a carbon layer. The substrate serves as a support structure and is typically copper or aluminum foil. The carbon layer is formed on the surface of the substrate to improve conductivity. The active material layer 242 is coated on the current collector 241 of the positive electrode 24, providing electrochemically active material. The electrolyte layer 25 covers the outer side of the active material layer 242 of the positive electrode 24, serving a function of ion conduction.

[0142] The electrolyte layer 25 can extend beyond the positive electrode 24 at both ends of the length direction X, and the length of the electrolyte layer 25 extending beyond the positive electrode 24 at either end of the length direction X can be: (length of electrolyte - length of positive electrode 24) / 2.

[0143] The electrolyte layer 25 can extend beyond the positive electrode 24 at both ends in the width direction Y, and the width of the electrolyte layer 25 extending beyond the positive electrode 24 at either end in the width direction Y can be: (width of electrolyte - width of positive electrode 24) / 2.

[0144] The thickness of the active material layer 242 of the positive electrode 24 can be the sum of the thickness of the active material layer 242 and the thickness of the groove 27.

[0145] The length of the active material layer 242 of the positive electrode 24 is denoted as L1, and the width is denoted as T1.

[0146] The thickness H2 of the electrolyte layer 25 = the thickness H3 of the solid electrolyte layer 25 + the depth H1 of the groove 27.

[0147] The length of electrolyte layer 25 is denoted as L3; the width of electrolyte layer 25 is denoted as T3.

[0148] The design of the inclined surface 271 of the groove 27: thickness = H2; length = L2; width = T2.

[0149] Design of the bottom wall 272 of the groove 27: Length = L1 - 2 * L2; Width = T1 - 2 * T2.

[0150] To ensure the uniformity of the electric field and the structure, the contact area between the bottom area of ​​the positive electrode 24 and the electrolyte layer 25 should be between 99% and 100%. The width of the groove 27 can be determined by the following formula:

[0151] 100%≥(T1-2*T2)(L1-2*L2) / (T1*L1)*100%≥99%.

[0152] To ensure that groove 27 can effectively disperse stress, the depth of groove 27 is within the following range:

[0153] H3≥H1≥0.5H3.

[0154] If the groove 27 is too shallow, it cannot effectively disperse shear stress; if the groove 27 is too deep, it may reduce the mechanical strength and electrochemical performance of the electrode.

[0155] Specific implementation example: The length and width of the negative electrode 26 are 80mm and 100mm respectively, and each end of the negative electrode 26 extends beyond the positive electrode 242mm. The length and width of the positive electrode 24 are 76mm and 96mm respectively.

[0156] Assuming the width L2 of groove 27 is 0.2mm, the calculation yields:

[0157] (T1-2*T2)(L1-2*L2) / (T1*L1)=99.5%.

[0158] That is, if the width is set to 0.2mm to meet the requirements, and the thickness of the electrolyte layer 25 is usually H3 = 200μm, then the range of values ​​for the depth of the groove 27 is:

[0159] 0.2mm≥H1≥0.1mm.

[0160] The method for determining the data of groove 27 includes the following steps:

[0161] Mechanical Analysis: A mathematical model was established to analyze the vertical shear stress distribution during the warm isostatic pressing process. By calculating the decomposition of shear force in the groove 27 and inclined plane 271, the depth of the groove 27, the length of the inclined plane 271, and the width of the inclined plane 271 were determined.

[0162] Experimental verification: The electrode performance under different groove 27 parameters, such as shear stress and electrode fracture, was tested through experiments to optimize the design parameters of groove 27.

[0163] Simulation: Using simulation tools such as finite element analysis (FEA), the stress distribution and electrode deformation during the warm isostatic pressing process are simulated to verify the effectiveness of the groove 27 design.

[0164] Common processing errors that may occur during production include:

[0165] Groove 27 dimensional tolerance: The depth, length and width of groove 27 are required to be ≤5μm.

[0166] Laser processing error: Laser cleaning of the electrolyte layer 25 exceeding the positive electrode 24 may cause material damage or dimensional deviation. Infrared sensors are used in real-time during production to detect and correct processing errors promptly.

[0167] Optimize the shape of groove 27: Consider using rounded corners in the beveled part of groove 27 to further reduce stress concentration. The rounded corner radius is 90°±1°, and the depth and width of groove 27 are equal, which can further optimize the design.

[0168] 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 battery cell, characterized by, include: A positive electrode, an electrolyte layer, and a negative electrode are stacked together. The electrolyte layer and the negative electrode form a combined structure. At least a portion of the combined structure extends beyond the positive electrode. The side of the electrolyte layer facing the positive electrode has a groove. At least a portion of the sidewall of the groove is inclined. The cross-sectional area of ​​the groove decreases from the groove opening to the groove bottom. A portion of the positive electrode is disposed within the groove. The shape of the portion of the positive electrode located within the groove is adapted to the shape of the groove.

2. The battery cell of claim 1, wherein, The groove has a bottom wall, which is connected to the side wall.

3. The battery cell of claim 1, wherein, The sidewalls are provided in multiple ways, and the multiple sidewalls are connected end to end, with at least a portion of each sidewall being an inclined surface.

4. The battery cell of claim 1, wherein, The electrolyte layer has a length direction and a width direction. The sidewalls of the groove include a first sidewall, a second sidewall, a third sidewall, and a fourth sidewall connected in sequence. The length directions of the first sidewall and the third sidewall are both extended along the width direction of the electrolyte layer. The length directions of the second sidewall and the fourth sidewall are both extended along the length direction of the electrolyte layer. The first sidewall, the second sidewall, the third sidewall, and the fourth sidewall are all at least partially inclined surfaces.

5. The battery cell as described in claim 4, characterized in that, The inclined planes corresponding to the first sidewall and the third sidewall have the same inclination angle, and the inclined planes corresponding to the second sidewall and the fourth sidewall have the same inclination angle.

6. The battery cell of claim 1, wherein, The positive electrode includes a current collector and an active material layer. The active material layer has a first surface and a second surface disposed opposite to each other in the thickness direction. The first surface is connected to the current collector, and the second surface is in contact with the bottom wall of the groove. The area of ​​the second surface is 95%-100% of the area of ​​the first surface.

7. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. The area of ​​the second surface is 99%-100% of the area of ​​the first surface.

8. The battery cell of any one of claims 1-7, wherein, The depth of the groove is less than or equal to 1 / 2 of the thickness of the electrolyte layer.

9. The battery cell according to any one of claims 1-7, characterized in that, The depth of the groove is greater than or equal to 1 / 3 of the thickness of the electrolyte layer.

10. The battery cell of any one of claims 1-7, wherein, At least one apex corner of the groove is rounded.

11. The battery cell of any one of claims 1-7, wherein, The inclination angle of the inclined surface is 45°-60°, and the inclination angle is the angle between the inclined surface and the thickness direction of the electrolyte layer.

12. The battery cell of any one of claims 1-7, wherein, The inclination angle of the inclined plane is 45°.

13. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-12.

14. An electrical device, comprising: Includes a battery cell according to any one of claims 1-12 or a battery device according to claim 13.

Images