Battery monomer, battery and electric device

Abstract

The embodiment of the utility model provides a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell, a top cover and an electrode assembly, the housing has an accommodation space and an opening. And the top cover hermetically covers the opening. The electrode assembly is arranged in the accommodating space. Wherein the top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected with the side, facing the electrode assembly, of the cover body, the other end of the connecting side wall extends in the direction away from the cover body, and the shell is connected with the outer side wall of the connecting side wall; at least part of the area, between the cover body and the shell, of the connecting side wall is recessed to form a groove, and the wall thickness, located at the groove, of the connecting side wall is not larger than the thickness of the joint of the shell and the connecting side wall. According to the battery monomer provided by the embodiment of the invention, the risk of cracking of the connecting structure between the shell and the top cover is reduced, the problem of failure of the connecting structure between the shell and the top cover is improved, and the service life of the battery monomer is prolonged.

Description

Technical Field

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

[0002] This section is intended to provide a background or context for the embodiments of the present application. No description herein is admitted to be prior art by virtue of its inclusion in this section.

[0003] In the battery production process, after the bare cell is placed in the shell and the top cover is closed, the shelled cell can be obtained. After the bare cell is placed in the shell, the shell cover needs to be welded to weld the shell and the top cover together. In the related art, when the bare cell expands during the cycle and generates gas during the charge and discharge process, it will cause cracks at the connection between the shell and the top cover, and there is a problem of failure of the connection structure between the shell and the top cover. Utility Model Content

[0004] In view of this, the embodiments of the present application hope to provide a battery cell, a battery and an electrical device, which can improve the problem of failure of the connection structure between the outer shell and the top cover and increase the service life of the battery cell.

[0005] To achieve the above-mentioned purpose, a first aspect of an embodiment of the present application provides a battery cell, comprising:

[0006] A housing having a receiving space and an opening;

[0007] A top cover, a sealing cover is arranged at the opening;

[0008] An electrode assembly is disposed in the accommodation space;

[0009] Wherein, the top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected to the side of the cover body facing the electrode assembly, and the other end extends in a direction away from the cover body, and the outer shell is connected to the connecting side wall; at least a part of the area of ​​the connecting side wall located between the cover body and the outer shell is recessed to form a groove, and the wall thickness of the connecting side wall located at the groove is not greater than the thickness at the connection between the outer shell and the connecting side wall.

[0010] In the battery cell provided in the embodiment of the present application, the top cover is provided with a cover body and a connecting side wall, and the shell is connected to the connecting side wall. This structure can improve the deformation capacity of the top cover, and is conducive to increasing the contact area and connection area between the top cover and the shell, and improving the shear resistance (also known as shear strength) of the connection between the shell and the top cover, that is, improving the maximum stress value that can be borne by the connection between the shell and the top cover under the action of shear force, thereby improving the structural strength of the connection between the top cover and the shell. In addition, at least a portion of the area of ​​the connecting side wall between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connection between the shell and the connecting side wall. Therefore, when the electrode assembly expands cyclically and generates gas during charge and discharge, the force is more likely to act on the groove. That is, the groove on the connecting side wall forms a force buffer zone at the connection between the shell and the top cover, thereby reducing the force on the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, improving the problem of failure of the connection structure between the shell and the top cover, and improving the service life of the battery cell.

[0011] In some embodiments, the inner side wall of the connecting side wall is recessed to form the groove.

[0012] In this embodiment, by forming the groove on the inner side wall connecting the side walls, it is beneficial to improve the aesthetics of the battery cell and can also prevent dust and other debris from being deposited in the groove.

[0013] In some embodiments, the groove is formed at the connection between the connecting side wall and the cover body.

[0014] In this embodiment, by setting the groove at the connection between the side wall and the cover body, and away from the end where the side wall is connected to the outer shell, when the connection between the outer shell and the top cover is subjected to force, the moment of the connecting side wall at the groove can be increased, which is further conducive to the deformation being concentrated at the position of the connecting side wall at the groove, thereby further reducing the risk of fatigue cracking of the connection structure between the outer shell and the top cover.

[0015] In some embodiments, the groove extends along an edge of the top cover.

[0016] The distances between any two positions of the groove in its extension direction and the edge of the top cover can be made the same, that is, the distances between any two positions of the groove in its extension direction and the outer wall connected to the side wall can be made the same, so that the force near the groove can be made more uniform.

[0017] In some embodiments, in a cross section perpendicular to the extending direction of the groove, a dimension of the groove in the height direction of the battery cell is H1, wherein 0.5 mm≤H1≤2 mm.

[0018] While ensuring that the connecting side wall has sufficient strength, it can also facilitate the transfer of force at the connection between the outer shell and the top cover to the groove, and is more conducive to concentrating the deformation at the groove, thereby reducing the force on the connecting structure between the outer shell and the top cover, reducing the risk of cracking of the connecting structure between the outer shell and the top cover, and increasing the service life of the top cover.

[0019] In some embodiments, in a cross section perpendicular to the extending direction of the groove, a dimension of the groove in the height direction of the battery cell is H1, wherein 0.5 mm≤H1≤1.5 mm.

[0020] It can be helpful to transfer the force at the connection between the shell and the top cover to the groove, which helps to concentrate the deformation at the groove. At the same time, it can further make the connecting side wall have sufficient strength, thereby improving the service life of the top cover.

[0021] In some embodiments, the connecting side wall includes a connecting body and a connecting area arranged at one end of the connecting body away from the cover body, the distance between the outer wall of the connecting area and the central axis of the battery cell is smaller than the distance between the connecting body and the central axis of the battery cell, the connecting area extends into the outer shell, and the end surface of the outer shell is connected to the end surface of the connecting body.

[0022] In this embodiment, by setting the distance between the outer wall of the connecting area and the central axis of the battery cell to be smaller than the distance between the connecting body and the central axis of the battery cell, during assembly, the connecting area is extended into the outer shell, and the end face of the outer shell is connected to the end face of the connecting body. In this way, when the outer shell is deformed, it is helpful to change the force mode between the outer shell and the top cover in the related technology, and the connecting area is helpful to support the outer shell, thereby improving the strength of the connection structure between the outer shell and the top cover.

[0023] In some embodiments, an outer surface of the connecting body is flush with an outer surface of the cover body.

[0024] By setting the outer surface of the connecting body to be flush with the outer surface of the cover body, it is beneficial to improve the aesthetics of the battery cell, and can also prevent dust and other debris from being deposited between the connecting body and the cover body. At the same time, it can also minimize the space occupied by the battery cell, thereby improving the energy density of the battery.

[0025] In some embodiments, an outer surface of the connecting body is flush with an outer surface of the housing.

[0026] In this embodiment, by setting the outer surface of the connecting body to be flush with the outer surface of the outer shell, it is beneficial to improve the aesthetics of the battery cell, and can also prevent dust and other debris from being deposited between the connecting body and the outer shell. At the same time, it can also reduce the space occupied by the battery cell as much as possible, thereby improving the energy density of the battery.

[0027] In some embodiments, a dimension of the connection area in a height direction of the battery cell is H2, wherein 0.5 mm ≤ H2 ≤ 4 mm.

[0028] In this embodiment, by setting the size of the connection area in the height direction of the battery cell to 0.5mm-4mm, the connection structure between the shell and the top cover has sufficient strength while also reducing the space occupied by the battery cell, thereby improving the energy density of the battery cell.

[0029] In some embodiments, a dimension of the connecting side wall in a height direction of the battery cell is H3, wherein 1.5 mm ≤ H3 ≤ 8 mm.

[0030] In this embodiment, by setting the size of the connecting side wall in the height direction of the battery cell to 1.5mm-8mm, the connection structure between the outer shell and the top cover has sufficient strength, which is conducive to concentrating the deformation at the groove, and at the same time, the space occupied by the battery cell is smaller, thereby improving the energy density of the battery cell.

[0031] In some embodiments, the thickness of the connection between the shell and the connecting side wall is L1, and the thickness of the connecting body is L2, wherein 1mm≤L2≤10L1.

[0032] The connection body can have sufficient strength, thereby improving the structural strength of the connection between the top cover and the shell, and it is also beneficial for the force at the connection between the shell and the top cover to be transmitted to the groove, so as to concentrate the deformation in the groove, thereby reducing the force on the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, improving the problem of failure of the connection structure between the shell and the top cover, and increasing the service life of the battery cell.

[0033] In some embodiments, the thickness of the connection between the shell and the connecting side wall is L1, and the thickness of the connecting body is L2, wherein 1mm≤L2≤4L1.

[0034] The connection body can have sufficient strength to improve the structural strength of the connection between the top cover and the shell, and it can also further facilitate the force of the connection between the shell and the top cover to be transmitted to the groove, so as to help concentrate the deformation in the groove, thereby reducing the force on the connection structure between the shell and the top cover, further reducing the risk of cracking of the connection structure between the shell and the top cover, improving the problem of failure of the connection structure between the shell and the top cover, and increasing the service life of the battery cell.

[0035] In some embodiments, the dimension of the cover body in the height direction of the shell is H4, wherein 1mm≤H4≤5mm; and / or the thickness of the connection between the shell and the connecting side wall is L1, wherein 0.4mm≤L1≤2mm.

[0036] By setting the height of the cover body to 1mm-5mm, the top cover can have sufficient strength to protect the electrode assembly in the accommodating space while reducing the weight and volume of the battery cell, and can reduce the material used for the top cover, reduce costs, and improve the overall performance of the battery.

[0037] By setting the thickness of the connection between the shell and the connecting side wall to 0.4mm-2mm, the connection between the top cover and the shell has sufficient connection strength, while reducing the weight and volume of the battery cell, reducing the material used for the top cover, reducing costs, and improving the overall performance of the battery.

[0038] In some embodiments, the dimension of the cover body in the height direction of the shell is H4, wherein 1.5 mm ≤ H4 ≤ 3 mm; and / or the thickness of the connection between the shell and the connecting side wall is L1, wherein 0.6 mm ≤ L1 ≤ 1.7 mm.

[0039] By setting the height of the cover body to 1.5mm-3mm, the top cover can have sufficient strength to protect the electrode assembly in the accommodating space, while further reducing the weight and volume of the battery cell, reducing the material used for the top cover, reducing costs, and further improving the overall performance of the battery.

[0040] By setting the thickness of the connection between the shell and the connecting side wall to 0.6mm-1.7mm, the connection between the top cover and the shell has sufficient connection strength, while further reducing the weight and volume of the battery cell, reducing the material used for the top cover, reducing costs, and further improving the overall performance of the battery.

[0041] A second aspect of an embodiment of the present application provides a battery, comprising at least one battery cell as described above.

[0042] The battery provided in the embodiment of the present application includes at least one battery cell of the embodiment of the present application, and the top cover is provided with a cover body and a connecting side wall, and the shell is connected to the connecting side wall. This structure can improve the deformation capacity of the top cover, and is conducive to increasing the contact area and connection area between the top cover and the shell, and improving the shear resistance (also known as shear strength) of the connection between the shell and the top cover, that is, improving the maximum stress value that can be borne by the connection between the shell and the top cover under the action of shear force, thereby improving the structural strength of the connection between the top cover and the shell. In addition, at least a portion of the area of ​​the connecting side wall between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connection between the shell and the connecting side wall. Therefore, when the electrode assembly expands cyclically and generates gas during charge and discharge, the force is more likely to act on the groove. That is, the groove on the connecting side wall forms a force buffer zone at the connection between the shell and the top cover, thereby reducing the force on the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, improving the problem of failure of the connection structure between the shell and the top cover, and improving the service life of the battery cell.

[0043] A third aspect of an embodiment of the present application provides an electrical device, comprising the battery described above, wherein the battery is used to provide electrical energy to the electrical device.

[0044] The electric device provided in the embodiment of the present application includes a battery, the battery includes at least one battery cell of the embodiment of the present application, the top cover is provided with a cover body and a connecting side wall, and the shell is connected to the connecting side wall. This structure can improve the deformation capacity of the top cover, and is conducive to increasing the contact area and connection area between the top cover and the shell, and improving the shear resistance (also known as shear strength) of the connection between the shell and the top cover, that is, improving the maximum stress value that can be borne by the connection between the shell and the top cover under the action of shear force, thereby improving the structural strength of the connection between the top cover and the shell. In addition, at least a portion of the area of ​​the connecting side wall between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connection between the shell and the connecting side wall. Therefore, when the electrode assembly cyclically expands and generates gas during charge and discharge, the force is more likely to act on the groove. That is, the groove on the connecting side wall forms a force buffer zone at the connection between the shell and the top cover, thereby reducing the force on the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, improving the problem of failure of the connection structure between the shell and the top cover, and improving the service life of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the structure of a vehicle provided in one embodiment of the present application;

[0046] Figure 2A three-dimensional exploded schematic diagram of a battery provided in one embodiment of the present application;

[0047] Figure 3 A top view of a battery cell provided in one embodiment of the present application;

[0048] Figure 4 for Figure 3 Section view in AA direction;

[0049] Figure 5 for Figure 4 The enlarged view of point B in the middle;

[0050] Figure 6 A schematic diagram of the deformation of the connection between the housing and the top cover provided in one embodiment of the present application when subjected to force;

[0051] Figure 7 The figure is a schematic diagram of cracking of the connection between the shell and the top cover in the prior art when subjected to stress.

[0052] Description of Reference Numerals

[0053] 10. Battery cell; 11. Shell; 11a. Accommodation space; 11b. Opening; 12. Top cover; 121. Cover body; 122. Connecting side wall; 122a. Groove; 122b. Connecting body; 122c. Connecting area; 20. Battery box; 21. First box body; 22. Second box body; 100. Battery; 200. Controller; 300. Motor; 1000. Vehicle. DETAILED DESCRIPTION

[0054] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present application and should not be regarded as an improper limitation on the present application.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions.

[0056] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0057] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations 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. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0058] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. 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 article generally indicates that the associated objects before and after are in an "or" relationship.

[0059] In the description of the embodiments of the present application, the orientation or position relationship indicated by technical terms such as "length", "width", "thickness", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "circumferential", "height direction", "first direction", and "second direction" are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed, operated or used in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0060] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like 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 mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0061] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical term "contact" should be understood in a broad sense, and may be direct contact or contact through an intermediate medium layer. It may be contact with essentially no interaction force between the two contacting parties, or it may be contact with interaction force between the two contacting parties.

[0062] With the development of clean energy, more and more devices use electric energy as driving energy, and then power batteries that can store more electric energy and can be charged and discharged repeatedly are developing rapidly, such as lithium-ion batteries. Among them, power batteries 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 aerospace and other fields.

[0063] With the country's vigorous promotion of new energy vehicles, new energy vehicles have ushered in a great opportunity for development. The safety and stability of automobiles have always been people's greatest concern. Therefore, improving the safety of new energy vehicles will be one of the important factors that determine whether new energy vehicles can be quickly popularized. Improving the safety of batteries is an important way to improve the safety of new energy vehicles.

[0064] In the present application, the battery cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, etc., which is not limited in the embodiments of the present application. The battery cell may be cylindrical, rectangular or in other shapes, etc., which is not limited in the embodiments of the present application.

[0065] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0066] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer. The negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode tab. The negative electrode current collector may be made of copper, and the negative electrode active material may be carbon or silicon. In order to ensure that a large current can pass without melting, the positive electrode tabs are multiple and stacked together, and the negative electrode tabs are multiple and stacked together. The material of the separator may be PP (polypropylene) or PE (polyethylene).

[0067] Illustratively, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode active material is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0068] Exemplarily, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0069] Illustratively, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0070] For example, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used.

[0071] Illustratively, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0072] Exemplarily, the negative electrode active material may adopt the negative electrode active material for the battery known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0073] The battery cell also includes a packaging film and a shell. The packaging film is coated on the outside of the electrode assembly, and the shell encapsulates the electrode assembly coated with the packaging film to form a battery cell. The packaging film can be a Mylar film, and the shell can be an aluminum shell. After the electrode assembly is wound and formed, the Mylar film and the shell are encapsulated through the Mylar wrapping process and the shelling process. Among them, the Mylar film plays a role in sealing and protecting the electrode assembly, and the Mylar film can effectively insulate the electrode assembly and the shell from each other to avoid internal short circuits in the battery cell. The shell plays a protective role.

[0074] Exemplarily, the housing includes a top cover and an outer shell, the housing is provided with an opening, and the top cover closes the opening to form a closed space for accommodating substances such as the electrode assembly and the electrolyte. The housing may be provided with one or more openings. The top cover may also be provided with one or more openings.

[0075] Exemplarily, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the electrode tab of the electrode assembly. The electrode terminal can be directly connected to the electrode tab, or indirectly connected to the electrode tab through an adapter. The electrode terminal can be provided on the top cover, or on the housing.

[0076] Exemplarily, an explosion-proof valve is provided on the housing, and the explosion-proof valve is used to release the internal pressure of the battery cell.

[0077] Exemplarily, the battery cells may be cylindrical battery cells, prismatic battery cells, soft-pack battery cells or battery cells of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries, etc. There are no particular limitations on the embodiments of the present application.

[0078] Exemplarily, the battery cell further includes a pressure relief structure, which may be disposed on the top cover or the outer shell to release the internal pressure or temperature of the battery cell.

[0079] The development of battery technology must take into account many design factors at the same time, such as energy density, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery reliability must also be considered.

[0080] For related technologies, see Figure 7 When gas is generated during the cyclic expansion of the electrode assembly and the charge and discharge process, force is exerted on the outer shell and the top cover, causing the outer shell to deform outward, thereby stretching the connection structure between the outer shell and the top cover, and further causing fatigue cracking at the connection between the outer shell and the top cover, which may cause the connection structure between the outer shell and the top cover to fail.

[0081] In order to improve the problem of failure of the connection structure between the outer shell and the top cover and to increase the service life of the battery cell, an embodiment of the present application provides a battery cell, which includes an outer shell, a top cover and an electrode assembly. The outer shell has a accommodating space and an opening. The top cover sealing cover is arranged at the opening. The electrode assembly is arranged in the accommodating space. Among them, the top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected to the side of the cover body facing the electrode assembly, and the other end extends in a direction away from the cover body, and the outer shell is connected to the outer side wall of the connecting side wall; at least a part of the area of ​​the connecting side wall between the cover body and the outer shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness at the connection between the outer shell and the connecting side wall.

[0082] In the battery cell provided in the embodiment of the present application, the top cover is provided with a cover body and a connecting side wall, and the shell is connected to the connecting side wall. This structure can improve the deformation capacity of the top cover, and is conducive to increasing the contact area and connection area between the top cover and the shell, and improving the shear resistance (also known as shear strength) of the connection between the shell and the top cover, that is, improving the maximum stress value that can be borne by the connection between the shell and the top cover under the action of shear force, thereby improving the structural strength of the connection between the top cover and the shell. In addition, at least a portion of the area of ​​the connecting side wall between the cover body and the shell is recessed to form a groove, and the wall thickness of the connecting side wall at the groove is not greater than the thickness of the connection between the shell and the connecting side wall. Therefore, when the electrode assembly expands cyclically and generates gas during charge and discharge, the force is more likely to act on the groove. That is, the groove on the connecting side wall forms a force buffer zone at the connection between the shell and the top cover, thereby reducing the force on the connection structure between the shell and the top cover, reducing the risk of cracking of the connection structure between the shell and the top cover, improving the problem of failure of the connection structure between the shell and the top cover, and improving the service life of the battery cell.

[0083] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0084] The battery mentioned in the embodiments of the present application refers to a battery cell including at least one battery cell provided in the embodiments of the present application. One or more battery cells provide a single physical module with higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. The battery generally includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0085] 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.

[0086] It should be noted that the technical solutions described in the embodiments of the present application are not limited to the batteries and electrical devices described above, but can also be applied to all batteries including a box and electrical devices using batteries. However, for the sake of simplicity, the following embodiments are described using electric vehicles as examples.

[0087] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. A controller 200, a motor 300 and a battery 100 may be provided inside the vehicle 1000, and the controller 200 is used to control the battery 100 to power the motor 300. For example, a battery 100 may be provided at the bottom, front or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000, for the circuit system of the vehicle 1000, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1000. In another embodiment of the present application, the battery 100 may not only be used as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0088] In order to meet different power requirements, the battery 100 may include a plurality of battery cells 10, which refers to the smallest unit constituting the battery 100 module or the battery 100 pack. A plurality of battery cells 10 may be connected in series, in parallel or in a hybrid connection, and a hybrid connection refers to a plurality of battery cells 10 having both series and parallel connections. A plurality of battery cells 10 may be directly connected in series, in parallel or in a hybrid connection, and then the whole formed by the plurality of battery cells 10 is contained in the box; of course, the battery 100 may also be a plurality of battery cells 10 connected in series, in parallel or in a hybrid connection to form a battery 100 module, and then a plurality of battery 100 modules are connected in series, in parallel or in a hybrid connection to form a whole, and are contained in the box. The battery 100 may also include other structures, for example, the battery 100 may also include a confluence component for realizing electrical connection between a plurality of battery cells 10. Each battery cell 10 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 10 may be cylindrical, flat, rectangular or in other shapes.

[0089] Please refer to Figure 2 The battery 100 includes a battery box 20 and at least one battery cell 10 , and the battery cell 10 is disposed in an installation space of the battery box 20 .

[0090] The battery box 20 can be a simple three-dimensional structure such as a single cuboid, cylinder or sphere, or a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders or spheres. The material of the battery box 20 can be alloy materials such as aluminum alloy, iron alloy, etc., or polymer materials such as polycarbonate, polyisocyanurate foam plastics, or composite materials such as glass fiber and epoxy resin.

[0091] The battery box 20 is used to accommodate the battery cell 10, and the battery box 20 can be a variety of structures. In some embodiments, the battery box 20 may include a first box body 21 and a second box body 22, the first box body 21 and the second box body 22 cover each other, and the first box body 21 and the second box body 22 jointly define an installation space for accommodating the battery cell 10. The second box body 22 may be a hollow structure with an opening 11b at one end, the first box body 21 is a plate-like structure, and the first box body 21 covers the opening 11b side of the second box body 22 to form a battery box 20 with an installation space; the first box body 21 and the second box body 22 may also be a hollow structure with one side open, and the opening 11b side of the first box body 21 covers the open side of the second box body 22 to form a battery box 20 with an installation space. Of course, the first box body 21 and the second box body 22 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0092] In order to improve the sealing performance after the first box body 21 and the second box body 22 are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 21 and the second box body 22 .

[0093] Assuming that the first box body portion 21 covers the top of the second box body portion 22 , the first box body portion 21 can also be referred to as an upper box cover, and the second box body portion 22 can also be referred to as a lower box cover.

[0094] In the battery 100, there can be one or more battery cells 10. If there are more than one battery cell 10, the battery cells 10 can be connected in series, in parallel or in a mixed connection. A mixed connection means that the battery cells 10 are connected in series and in parallel. The battery cells 10 can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the battery cells 10 is accommodated in the battery box 20; of course, the battery cells 10 can also be connected in series, in parallel or in a mixed connection to form a battery module 100, and then the battery modules 100 are connected in series, in parallel or in a mixed connection to form a whole, and then accommodated in the battery box 20.

[0095] For example, the battery cell 10 may include a lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., which is not limited in the embodiments of the present application. The battery cell 10 may be cylindrical, flat, rectangular, or in other shapes, etc., which is not limited in the embodiments of the present application. The battery cell 10 is generally divided into three types according to the packaging method: cylindrical battery cells 10, square battery cells 10, and soft-pack battery cells 10, which is not limited in the embodiments of the present application.

[0096] The present application embodiment provides a battery cell. Figures 3 to 6 The battery cell 10 includes a shell 11, a top cover 12 and an electrode assembly. The shell 11 has a accommodating space 11a and an opening 11b. The sealing cover of the top cover 12 is arranged at the opening 11b. The electrode assembly is arranged in the accommodating space 11a. Among them, the top cover 12 is provided with a cover body 121 and a connecting side wall 122, one end of the connecting side wall 122 is connected to the side of the cover body 121 facing the electrode assembly, and the other end extends in a direction away from the cover body 121, and the shell 11 is connected to the outer wall of the connecting side wall 122; at least a part of the area of ​​the connecting side wall 122 between the cover body 121 and the shell 11 is recessed to form a groove 122a, and the wall thickness of the connecting side wall 122 at the groove 122a is not greater than the thickness at the connection between the shell 11 and the connecting side wall 122.

[0097] Here, the housing may be in a cylindrical, flat, rectangular or other shapes.

[0098] It should be noted that the height direction of the housing 11 described in the embodiment of the present application is the direction from the opening 11b to the accommodating space 11a, or the opposite direction from the opening 11b to the accommodating space 11a. When the housing 11 is cylindrical, the height direction of the housing 11 is the axial direction of the housing 11.

[0099] It should be noted that the specific method of connecting the top cover 12 and the housing 11 is not limited here, for example, welding.

[0100] Exemplarily, the cover body 121 and the connecting side wall 122 are an integrated structure. The integrated cover body 121 and the connecting side wall 122 can reduce the number of parts, reduce assembly time, and improve assembly efficiency and structural strength.

[0101] Of course, the cover body 121 and the connecting side wall 122 may also be a split structure, for example, the connecting side wall 122 is welded to the side of the cover body 121 close to the electrode assembly. The split cover body 121 and the connecting side wall 122 are conducive to molding.

[0102] Exemplarily, at least a portion of the connecting side wall 122 extends into the accommodating space 11 a through the opening 11 b , and then the outer side wall of the connecting side wall 122 is connected to the outer shell 11 .

[0103] Here, the top cover 12 is provided with a cover body 121 and a connecting side wall 122. On the one hand, the outer shell 11 is connected to the outer side wall of the connecting side wall 122. When a force is applied to the connection between the outer shell 11 and the top cover 12, a moment can be formed on the connecting side wall 122, so that the connecting side wall 122 or the cover body 121 can be deformed (see Figure 7 ), that is, when the electrode assembly expands cyclically and generates gas during charge and discharge, when a force is applied to the connection between the outer shell 11 and the top cover 12, the force is easily transmitted to the top cover 12 to deform the connecting side wall 122. On the other hand, at least a portion of the connecting side wall 122 located between the cover body 121 and the outer shell 11 is recessed to form a groove 122a, and the wall thickness of the connecting side wall 122 located at the groove 122a is not greater than the thickness of the connection between the outer shell 11 and the connecting side wall 122, which is conducive to weakening the strength of the connecting side wall 122 located at the groove 122a. Therefore, when a force is applied to the connection between the outer shell 11 and the top cover 12, the force is more likely to act on the groove 122a of the connecting side wall 122. In other words, the position of the connecting side wall 122 located at the groove 122a is equivalent to forming a force buffer zone at the connection between the outer shell 11 and the top cover 12.

[0104] The connecting side wall 122 is recessed in at least a portion of the area between the cover body 121 and the outer shell 11 to form the groove 122a, which means that the connecting side wall 122 is recessed in at least a portion of the area in the height direction of the battery cell 10 and between the cover body 121 and the outer shell 11 to form the groove 122a, which is equivalent to thinning a portion of the connecting side wall 122 to form the groove 122a, thereby weakening the strength of the connecting side wall 122 at the groove 122a.

[0105] Here, the wall thickness L3 of the connecting side wall 122 at the groove 122a is not greater than the thickness L1 at the connection between the shell 11 and the connecting side wall 122, that is, the wall thickness of the connecting side wall 122 at the groove 122a is less than or equal to the thickness at the connection between the shell 11 and the connecting side wall 122, which is conducive to the deformation being concentrated at the groove 122a.

[0106] The top cover 12 is generally perpendicular to the side of the outer shell 11, and the outer shell 11 is deformed outward, and shear force is generated at the connection between the outer shell 11 and the top cover 12. When the electrode assembly expands cyclically and generates gas during charging and discharging, the outer shell 11 is subjected to force, so that the deformation is concentrated at the position where the connecting side wall 122 is located at the groove 122a, thereby reducing the shear force on the connection between the outer shell 11 and the top cover 12, reducing the risk of fatigue cracking of the connection structure between the outer shell 11 and the top cover 12, improving the problem of failure of the connection structure between the outer shell 11 and the top cover 12, and improving the service life of the battery cell 10.

[0107] In the battery cell 10 provided in the embodiment of the present application, the top cover 12 is provided with a cover body 121 and a connecting side wall 122, and the outer shell 11 is connected to the connecting side wall 122. This structure can improve the deformation ability of the top cover 12, and is beneficial to increase the contact area and connection area between the top cover 12 and the outer shell 11, and improve the shear resistance (also called shear strength) of the connection between the outer shell 11 and the top cover 12, that is, improve the maximum stress value that the connection between the outer shell 11 and the top cover 12 can bear under the action of shear force, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11. In addition, at least a portion of the connecting side wall 122 located between the cover body 121 and the outer shell 11 is recessed to form a groove 122a, and the wall thickness of the connecting side wall 122 located at the groove 122a is no greater than the thickness at the connection between the outer shell 11 and the connecting side wall 122. Therefore, when the electrode assembly cyclically expands and generates gas during charging and discharging, when a force is applied to the connection between the outer shell 11 and the top cover 12, the force is more likely to act on the groove 122a. In other words, the groove 122a on the connecting side wall 122 forms a force buffer zone at the connection between the outer shell 11 and the top cover 12, thereby reducing the force on the connection structure between the outer shell 11 and the top cover 12, reducing the risk of cracking of the connection structure between the outer shell 11 and the top cover 12, improving the problem of failure of the connection structure between the outer shell 11 and the top cover 12, and increasing the service life of the battery cell 10.

[0108] It should be noted that the specific location of the groove 122a is not limited here.

[0109] For some examples, see Figures 4 to 6 The inner side wall of the connecting side wall 122 is recessed to form a groove 122 a. In other words, the groove 122 a is formed on the inner side wall of the connecting side wall 122 .

[0110] In this embodiment, the groove 122 a is formed on the inner side wall of the connecting side wall 122 , which is beneficial to improving the aesthetics of the battery cell 10 and can also prevent dust and other debris from being deposited in the groove 122 a .

[0111] In some other embodiments, the outer side wall of the connecting side wall 122 is recessed to form a groove 122 a. In other words, the groove 122 a is formed on the outer side wall of the connecting side wall 122 .

[0112] It is understandable that the groove 122 a can be formed at any position between the housing 11 and the cover body 121 .

[0113] For some examples, see Figure 5 The groove 122 a is formed at the connection between the side wall 122 and the cover body 121 .

[0114] That is, one end of the connecting side wall 122 connected to the cover body 121 forms a groove 122 a and is connected to the cover body 121 through the area where the groove 122 a is formed.

[0115] In this embodiment, the groove 122a is set at the connection between the connecting side wall 122 and the cover body 121, and is far away from the end where the connecting side wall 122 is connected to the shell 11. In this way, when the connection between the shell 11 and the top cover 12 is subjected to force, the moment of the connecting side wall 122 at the groove 122a can be increased, which is further conducive to the deformation being concentrated at the position where the connecting side wall 122 is located at the groove 122a (see Figure 6 ), thereby further reducing the risk of fatigue cracking of the connection structure between the shell 11 and the top cover 12.

[0116] In some embodiments, the groove 122 a extends along an edge of the top cover 12 .

[0117] Here, the groove 122 a extends along the edge of the top cover 12 , that is, when projected on a plane parallel to the top cover 12 , the contour shape of the center line of the groove 122 a along the extension direction is completely or substantially the same as the contour shape of the top cover 12 .

[0118] It can be understood that the groove 122a extends along the edge of the top cover 12, so that the distance between any two positions of the groove 122a in its extension direction and the edge of the top cover 12 can be the same, that is, the distance between any two positions of the groove 122a in its extension direction and the outer wall connected to the side wall 122 can be the same, so that the force near the groove 122a can be made more uniform.

[0119] It should be noted that the top cover 12 may be formed with the groove 122a in a partial area between the cover body 121 and the connecting side wall 122, or may be formed with the groove 122a in the entire area between the cover body 121 and the connecting side wall 122, that is, the top cover 12 is provided with a circle of grooves 122a extending along the edge of the top cover 12. Here, the edge of the top cover 12 refers to the outer side wall of the connecting side wall 122.

[0120] For example, when the battery cell 10 is cylindrical, the top cover 12 may be provided with a circle of grooves 122 a extending along the edge of the top cover 12 , or may be partially surrounded by the grooves 122 a .

[0121] When the battery cell 10 is rectangular, the groove 122a may be formed partially or entirely on the long side or partially or entirely on the short side. In some embodiments, the top cover 12 is provided with a circle of grooves 122a corresponding to the contour of the top cover 12 .

[0122] For some examples, see Figure 5 and Figure 6 In a cross section perpendicular to the extending direction of the groove 122a, the dimension of the groove 122a in the height direction of the battery cell 10 is H1, wherein 0.5mm≤H1≤2mm, for example, 0.5mm, 0.8mm, 1mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2mm, etc.

[0123] Here, the width of the groove 122 a refers to a size of the groove 122 a in a height direction of the battery cell 10 .

[0124] It can be understood that the larger the width of the groove 122a, the more conducive it is for the force at the connection between the shell 11 and the top cover 12 to be transmitted to the groove 122a, that is, it is more conducive to concentrating the deformation at the groove 122a, but it will affect the structural strength of the connecting side wall 122 at the groove 122a.

[0125] In this embodiment, by setting the width of the groove 122a to 0.5mm-2mm, the connecting side wall 122 can have sufficient strength, and it is also beneficial to transfer the force at the connection between the outer shell 11 and the top cover 12 to the groove 122a, which is more conducive to concentrating the deformation at the groove 122a, thereby reducing the force on the connecting structure between the outer shell 11 and the top cover 12, reducing the risk of cracking of the connecting structure between the outer shell 11 and the top cover 12, and improving the service life of the top cover 12.

[0126] In some other embodiments, please refer to Figure 5 and Figure 6 In a cross section perpendicular to the extending direction of the groove 122a, the dimension of the groove 122a in the height direction of the battery cell 10 is H1, wherein 0.5mm≤H1≤1.5mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm, etc.

[0127] In this embodiment, by setting the width of the groove 122a to 0.5mm-1.5mm, the force at the connection between the shell 11 and the top cover 12 can be transferred to the groove 122a, which helps to concentrate the deformation at the groove 122a. At the same time, the connecting side wall 122 can be further made to have sufficient strength, thereby improving the service life of the top cover 12.

[0128] It should be noted that the specific connection method between the housing 11 and the connecting side wall 122 is not limited here.

[0129] For some examples, see Figure 5 and Figure 6 The connecting side wall 122 includes a connecting body 122b and a connecting area 122c arranged at one end of the connecting body 122b away from the cover body 121. The distance between the outer wall of the connecting area 122c and the central axis of the battery cell 10 is smaller than the distance between the connecting body 122b and the central axis of the battery cell 10. The connecting area 122c extends into the outer shell 11, and the end face of the outer shell 11 is connected to the end face of the connecting body 122b.

[0130] The connecting side wall 122 includes a connecting body 122 b and a connecting area 122 c arranged at one end of the connecting body 122 b away from the cover body 121 , that is, the connecting side wall 122 includes the connecting body 122 b and the connecting area 122 c arranged in sequence along the height direction of the battery cell 10 .

[0131] The distance between the outer wall of the connection area 122c and the central axis of the battery cell 10 is smaller than the distance between the connection body 122b and the central axis of the battery cell 10. In this way, a step surface facing away from the cover body 121 can be formed between the connection body 122b and the connection area 122c.

[0132] The connection area 122c extends into the housing 11, and the end surface of the housing 11 is connected to the end surface of the connection body 122b, that is, the end surface of the housing 11 facing the cover body 121 is connected to the step surface formed on the connection body 122b (for example, by welding). In this way, when the housing 11 is deformed, it is helpful to change the force receiving mode between the housing 11 and the top cover 12 in the related art, thereby improving the strength of the connection structure between the housing 11 and the top cover 12.

[0133] Here, the outer wall of the connection area 122c can be in contact with the inner wall of the shell 11. In this way, when the shell 11 is deformed, the connection area 122c is conducive to supporting the shell 11, thereby improving the strength of the connection structure between the shell 11 and the top cover 12.

[0134] It is understandable that the outer wall of the connection area 122c and the inner wall of the housing 11 may also be connected together, for example, by welding.

[0135] Of course, there may also be a certain gap between the outer wall of the connection area 122 c and the inner wall of the housing 11 .

[0136] In this embodiment, by setting the distance between the outer wall of the connection area 122c and the central axis of the battery cell 10 to be smaller than the distance between the connection body 122b and the central axis of the battery cell 10, during assembly, the connection area 122c is extended into the outer shell 11, and the end face of the outer shell 11 is connected to the end face of the connection body 122b. In this way, when the outer shell 11 is deformed, it is helpful to change the force mode between the outer shell 11 and the top cover 12 in the related technology, and the connection area 122c is helpful to support the outer shell 11, thereby improving the strength of the connection structure between the outer shell 11 and the top cover 12.

[0137] For some examples, see Figure 5 , the outer surface of the connecting body 122 b is flush with the outer surface of the cover body 121 .

[0138] That is, there is no step surface between the outer surface of the connection body 122b and the outer surface of the cover body 121. In other words, the distance between the outer surface of the connection body 122b and the central axis of the battery cell 10 is equal to the distance between the outer surface of the cover body 121 and the central axis of the battery cell 10.

[0139] In this embodiment, by setting the outer surface of the connecting body 122b to be flush with the outer surface of the cover body 121, it is beneficial to improve the aesthetics of the battery cell 10, and can also prevent dust and other debris from being deposited between the connecting body 122b and the cover body 121. At the same time, it can also reduce the occupied space of the battery cell 10 as much as possible, thereby improving the energy density of the battery 100.

[0140] For some examples, see Figure 5 , the outer surface of the connecting body 122 b is flush with the outer surface of the housing 11 .

[0141] That is, there is no step surface between the outer surface of the connecting body 122b and the outer surface of the housing 11. In other words, the distance between the outer surface of the connecting body 122b and the central axis of the battery cell 10 is equal to the distance between the outer surface of the housing 11 and the central axis of the battery cell 10.

[0142] In this embodiment, by setting the outer surface of the connecting body 122b to be flush with the outer surface of the outer shell 11, it is beneficial to improve the aesthetics of the battery cell 10, and can also prevent dust and other debris from being deposited between the connecting body 122b and the outer shell 11, while also reducing the space occupied by the battery cell 10 as much as possible, thereby improving the energy density of the battery 100.

[0143] For some examples, see Figure 5 and Figure 6The dimension of the connection area 122c in the height direction of the battery cell 10 is H2, wherein 0.5 mm ≤ H2 ≤ 4 mm, for example, 0.5 mm, 0.7 mm, 1 mm, 1.3 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.9 mm, 3 mm, 3.2 mm, 3.5 mm, 3.7 mm, 3.9 mm or 4 mm, etc.

[0144] It can be understood that the larger the size of the connection area 122c in the height direction of the battery cell 10, the more conducive it is to improving the strength of the connection structure between the outer shell 11 and the top cover 12, and the smaller the size of the connection area 122c in the height direction of the battery cell 10, the more conducive it is to reducing the occupied space of the battery cell 10, thereby improving the energy density of the battery cell 10.

[0145] In this embodiment, by setting the size of the connection area 122c in the height direction of the battery cell 10 to 0.5mm-4mm, the connection structure between the outer shell 11 and the top cover 12 has sufficient strength, and the space occupied by the battery cell 10 can be smaller, thereby improving the energy density of the battery cell 10.

[0146] For some examples, see Figure 5 and Figure 6 The dimension of the connecting side wall 122 in the height direction of the battery cell 10 is H3, wherein 1.5 mm ≤ H3 ≤ 8 mm, for example, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, 5 mm, 5.3 mm, 5.5 mm, 5.7 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 7.8 mm or 8 mm, etc.

[0147] Here, the dimension of the connecting side wall 122 in the height direction of the battery cell 10 is the height of the connecting side wall 122 .

[0148] It can be understood that the larger the size of the connecting side wall 122 in the height direction of the battery cell 10, the more conducive it is to improving the strength of the connection structure between the outer shell 11 and the top cover 12, and the more conducive it is to concentrating the deformation at the groove 122a. The smaller the size of the connecting area 122c in the height direction of the battery cell 10, the more conducive it is to reducing the occupied space of the battery cell 10, thereby improving the energy density of the battery cell 10.

[0149] In this embodiment, by setting the size of the connecting side wall 122 in the height direction of the battery cell 10 to 1.5mm-8mm, the connection structure between the outer shell 11 and the top cover 12 has sufficient strength, which is conducive to concentrating the deformation at the groove 122a. At the same time, the space occupied by the battery cell 10 can be smaller, thereby improving the energy density of the battery cell 10.

[0150] For some embodiments, please refer to Figure 5 and Figure 6 The thickness of the connection between the shell 11 and the connecting side wall 122 is L1, and the thickness of the connecting body 122b is L2, wherein 1mm≤L2≤10L1. That is, the thickness of the connecting body 122b is greater than or equal to 1mm and less than or equal to ten times the thickness of the connection between the shell 11 and the connecting side wall 122.

[0151] In this embodiment, by setting the thickness of the connecting body 122b to 1mm≤L2≤10L1, the connecting body 122b can have sufficient strength, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and at the same time, it is beneficial for the force at the connection between the outer shell 11 and the top cover 12 to be transferred to the groove 122a, which is beneficial for the deformation to be concentrated in the groove 122a, thereby reducing the force on the connection structure between the outer shell 11 and the top cover 12, reducing the risk of cracking of the connection structure between the outer shell 11 and the top cover 12, improving the problem of failure of the connection structure between the outer shell 11 and the top cover 12, and improving the service life of the battery cell 10.

[0152] In some other embodiments, please refer to Figure 5 and Figure 6 The thickness of the connection between the shell 11 and the connecting side wall 122 is L1, and the thickness of the connecting body 122b is L2, wherein 1mm≤L2≤4L1. That is, the thickness of the connecting body 122b is greater than or equal to 1mm and less than or equal to four times the thickness of the connection between the shell 11 and the connecting side wall 122.

[0153] In this embodiment, by setting the thickness of the connecting body 122b to 1mm≤L2≤4L1, the connecting body 122b can have sufficient strength, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and can further facilitate the force at the connection between the outer shell 11 and the top cover 12 to be transmitted to the groove 122a, so as to facilitate the deformation to be concentrated in the groove 122a, thereby reducing the force on the connection structure between the outer shell 11 and the top cover 12, further reducing the risk of cracking of the connection structure between the outer shell 11 and the top cover 12, improving the problem of failure of the connection structure between the outer shell 11 and the top cover 12, and improving the service life of the battery cell 10.

[0154] For some embodiments, please refer to Figure 5 and Figure 6 The dimension of the cover body 121 in the height direction of the housing 11 is H4, wherein 1mm≤H4≤5mm, for example, 1mm, 1.3mm, 1.4mm, 1.5mm, 1.7mm, 2mm, 3mm, 3.3mm, 3.5mm, 3.8mm, 4mm, 4.4mm, 4.5mm, 4.6mm or 5mm, etc.

[0155] In this embodiment, by setting the height of the cover body 121 to 1mm-5mm, the top cover 12 can have sufficient strength to protect the electrode assembly in the accommodating space 11a, while reducing the weight and volume of the battery cell 10, and can reduce the material used for the top cover 12, reduce costs, and improve the overall performance of the battery 100.

[0156] In some other embodiments, please refer to Figure 5 and Figure 6 The dimension of the cover body 121 in the height direction of the housing 11 is H4, wherein 1.5 mm ≤ H4 ≤ 3 mm, for example, 1.5 mm, 1.6 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm or 3 mm, etc.

[0157] In this embodiment, by setting the height of the cover body 121 to 1.5mm-3mm, the top cover 12 can have sufficient strength to protect the electrode assembly in the accommodating space 11a, while further reducing the weight and volume of the battery cell 10, reducing the material used for the top cover 12, reducing costs, and further improving the overall performance of the battery 100.

[0158] For some examples, see Figure 5 and Figure 6 The thickness of the connection between the housing 11 and the connecting side wall 122 is L1, wherein 0.4 mm ≤ L1 ≤ 2 mm, for example, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.3 mm, 1.5 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2 mm.

[0159] The thickness of the connection between the shell 11 and the connecting side wall 122 is L1, that is, the thickness of the shell 11 near the opening 11b is L1.

[0160] It should be noted that the shell 11 may include areas of different thickness. For example, along the height direction of the shell 11, the shell 11 includes an area close to one end of the opening 11b and an area away from one end of the opening 11b. By setting the thickness of the area close to one end of the opening 11b to be greater than the thickness of the area away from the one end of the opening 11b, the connection strength at the connection between the top cover 12 and the shell 11 can be improved.

[0161] In this embodiment, by setting the thickness of the connection between the outer shell 11 and the connecting side wall 122 to 0.4mm-2mm, the connection between the top cover 12 and the outer shell 11 has sufficient connection strength, while reducing the weight and volume of the battery cell 10, reducing the material used for the top cover 12, reducing costs, and improving the overall performance of the battery 100.

[0162] In some other embodiments, please refer to Figure 5 and Figure 6 The thickness of the connection between the housing 11 and the connecting side wall 122 is L1, wherein 0.6 mm ≤ L1 ≤ 1.7 mm, for example, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm or 1.7 mm, etc.

[0163] In this embodiment, by setting the thickness of the connection between the outer shell 11 and the connecting side wall 122 to 0.6mm-1.7mm, the connection between the top cover 12 and the outer shell 11 has sufficient connection strength, while further reducing the weight and volume of the battery cell 10, reducing the material used for the top cover 12, reducing costs, and further improving the overall performance of the battery 100.

[0164] It should be noted that the dimension H1 of the groove 122a in the height direction of the battery cell 10, the dimension H2 of the connection area 122c in the height direction of the battery cell 10, the dimension H3 of the connection side wall 122 in the height direction of the battery cell 10, the dimension H4 of the cover body 121 in the height direction of the outer shell 11, the thickness L1 at the connection between the outer shell 11 and the connection side wall 122, the thickness L2 of the connection body 122b, the wall thickness L3 of the connection side wall 122 at the groove 122a and other values ​​can be tested and calculated by high-precision thickness gauges, vernier calipers and other instruments at room temperature when the top cover 12 is not assembled.

[0165] The battery cell 10 of the present application is further described below in conjunction with specific test examples.

[0166] The test sample of the embodiment of the present application: the top cover 12 is provided with a cover body 121 and a connecting side wall 122, one end of the connecting side wall 122 is connected to the side of the cover body 121 facing the electrode assembly, and the other end extends in a direction away from the cover body 121, and the outer shell 11 is connected to the outer wall of the connecting side wall 122; at least a part of the area of ​​the connecting side wall 122 located between the cover body 121 and the outer shell 11 is recessed to form a groove 122a, and the wall thickness of the connecting side wall 122 at the groove 122a is not greater than the thickness at the connection between the outer shell 11 and the connecting side wall 122.

[0167] By performing charge and discharge cycle experiments on the test samples and the control group of the embodiment of the present application, and recording the number of cycles, the number of cycles of the five control groups of the embodiment of the present application are 3010, 3312, 3126, 3385, and 3215, respectively, and the average number of cycles of the five control groups of the embodiment of the present application is 3209 times. The number of cycles of the five test samples of the control group are 3863, 3615, 3657, 3742, and 3796, respectively, and the average number of cycles of the five test samples of the embodiment of the present application is 3734 times. The average value is increased by 16.36% compared with the average value of the control group. When the electrode assembly expands cyclically and generates gas during charge and discharge, force will be generated on the connection between the outer shell 11 and the top cover 12. The number of cycles of the battery cell 10 provided in the embodiment of the present application is much greater than the number of cycles of the control group. That is to say, the battery cell 10 provided in the embodiment of the present application reduces the risk of cracking of the connection structure between the outer shell 11 and the top cover 12, improves the problem of failure of the connection structure between the outer shell 11 and the top cover 12, improves fatigue performance, reduces overall weld thermal deformation strain, and increases the service life of the battery cell 10.

[0168] In the description of the present application, the description with reference to the terms "in one embodiment", "in some embodiments", "in other embodiments", "in yet other embodiments", or "exemplary" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine the different embodiments or examples described in the present application and the features of the different embodiments or examples, without contradiction.

[0169] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving space and an opening; A top cover, a sealing cover is arranged at the opening; An electrode assembly is disposed in the accommodation space; Wherein, the top cover is provided with a cover body and a connecting side wall, one end of the connecting side wall is connected to the side of the cover body facing the electrode assembly, and the other end extends in a direction away from the cover body, and the outer shell is connected to the connecting side wall; at least a part of the area of ​​the connecting side wall located between the cover body and the outer shell is recessed to form a groove, and the wall thickness of the connecting side wall located at the groove is not greater than the thickness at the connection between the outer shell and the connecting side wall.

2. The battery cell according to claim 1, characterized in that: The inner side wall of the connecting side wall is recessed to form the groove.

3. The battery cell according to claim 1, characterized in that: The groove is formed at the connection between the connecting side wall and the cover body.

4. The battery cell according to claim 1, characterized in that: The groove extends along an edge of the top cover.

5. The battery cell according to any one of claims 1 to 4, characterized in that: In a cross section perpendicular to an extending direction of the groove, a dimension of the groove in a height direction of the battery cell is H1, wherein 0.5 mm ≤ H1 ≤ 2 mm.

6. The battery cell according to any one of claims 1 to 4, characterized in that: In a cross section perpendicular to the extending direction of the groove, a dimension of the groove in the height direction of the battery cell is H1, wherein 0.5 mm≤H1≤1.5 mm.

7. The battery cell according to any one of claims 1 to 4, characterized in that: The connecting side wall includes a connecting body and a connecting area arranged at one end of the connecting body away from the cover body, the distance between the outer wall of the connecting area and the central axis of the battery cell is smaller than the distance between the connecting body and the central axis of the battery cell, the connecting area extends into the outer shell, and the end face of the outer shell is connected to the end face of the connecting body.

8. The battery cell according to claim 7, characterized in that: The outer surface of the connecting body is flush with the outer surface of the cover body; and / or the outer surface of the connecting body is flush with the outer surface of the outer shell.

9. The battery cell according to claim 7, characterized in that: The dimension of the connection area in the height direction of the battery cell is H2, wherein 0.5 mm≤H2≤4 mm.

10. The battery cell according to claim 7, characterized in that: The dimension of the connecting side wall in the height direction of the battery cell is H3, wherein 1.5 mm≤H3≤8 mm.

11. The battery cell according to claim 7, characterized in that: The thickness of the connection between the shell and the connection side wall is L1, and the thickness of the connection body is L2, wherein 1mm≤L2≤10L1.

12. The battery cell according to claim 7, characterized in that: The thickness of the connection between the shell and the connection side wall is L1, and the thickness of the connection body is L2, wherein 1mm≤L2≤4L1.

13. The battery cell according to any one of claims 1 to 4, characterized in that: The dimension of the cover body in the height direction of the shell is H4, wherein 1mm≤H4≤5mm; and / or the thickness of the connection between the shell and the connecting side wall is L1, wherein 0.4mm≤L1≤2mm.

14. The battery cell according to any one of claims 1 to 4, characterized in that: The dimension of the cover body in the height direction of the shell is H4, wherein 1.5 mm ≤ H4 ≤ 3 mm; and / or the thickness of the connection between the shell and the connecting side wall is L1, wherein 0.6 mm ≤ L1 ≤ 1.7 mm.

15. A battery, characterized in that: The invention comprises at least one battery cell according to any one of claims 1 to 14.

16. An electrical device, characterized in that: The battery according to claim 15 is used to provide electrical energy to the electrical device.

Images