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 comprises a cover body, a connecting side wall and a groove formed between the cover body and the connecting side wall, and the end part of the shell extends into the groove and is connected with the top cover. According to the battery monomer provided by the embodiment of the invention, when the electrode assembly circularly expands and generates gas during charging and discharging to generate a force effect on the joint of the shell and the top cover, the shell deforms outwards, and the connecting side wall plays a role in limiting and supporting the shell, so that the continuous outward deformation of the shell can be limited to a certain extent; the risk of fatigue 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 single battery 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] The top cover comprises a cover body, a connecting side wall and a groove formed between the cover body and the connecting side wall, and the end of the shell extends into the groove and is connected to the top cover.

[0010] In the battery cell provided in the embodiment of the present application, the top cover sealing cover is arranged at the opening of the outer shell. By setting the top cover to include a cover body and a connecting side wall, and forming a groove between the cover body and the connecting side wall, during assembly, the end of the outer shell can be extended into the groove and connected to the top cover. As a result, when the electrode assembly cyclically expands and gas is generated during charging and discharging, when force is applied to the connection between the outer shell and the top cover, the outer shell will deform outward, and the connecting side wall will limit and support the outer shell, thereby limiting the outer shell from further deforming outward to a certain extent, reducing the risk of fatigue cracking of the connection structure between the outer shell and the top cover, improving the problem of failure of the connection structure between the outer shell and the top cover, and increasing the service life of the battery cell.

[0011] In some embodiments, the shell includes a main body segment and a connecting segment connected to the main body segment, the connecting segment extends into the groove and is connected to the top cover, and the distance between the connecting segment and the central axis of the battery cell is smaller than the distance between the main body segment and the central axis of the battery cell.

[0012] By setting the distance between the connecting section and the central axis of the battery cell to be smaller than the distance between the main section and the central axis of the battery cell, the main section can be expanded outward as much as possible while the connecting section is extended into the groove and connected to the top cover, thereby increasing the size of the accommodating space and further increasing the energy density of the battery cell.

[0013] In some embodiments, the shell includes a transition section, the main body section and the connecting section are connected by the transition section, the plane where the main body section is located is parallel to the plane where the connecting section is located, and along the direction from the main body section to the connecting section, the distance between the transition section and the central axis of the battery cell gradually decreases.

[0014] By setting a transition section in the shell, the distance between the transition section and the central axis of the battery cell gradually decreases along the direction from the main section to the connecting section, thereby increasing the size of the accommodating space as much as possible and further improving the energy density of the battery cell.

[0015] In some embodiments, the height of the top cover at the groove is H1, wherein 0.2 mm ≤ H1 ≤ 1.5 mm.

[0016] By setting the height of the top cover at the groove to 0.2mm-1.5mm, the height of the top cover at the groove can satisfy the penetration welding between the top cover and the end of the shell, and the top cover at the groove can have sufficient structural strength.

[0017] In some embodiments, the height of the top cover at the groove is H1, wherein 0.3 mm ≤ H1 ≤ 1 mm.

[0018] By setting the height of the top cover at the groove to 0.3 mm-1 mm, penetration welding between the top cover and the end of the shell can be facilitated, and further the top cover has sufficient structural strength at the groove.

[0019] In some embodiments, in a cross section perpendicular to an extension direction of the groove, a width of the groove is L1, wherein 0.4 mm ≤ L1 ≤ 3.5 mm.

[0020] By setting the width of the groove to 0.4mm-3.5mm, it is beneficial for the end of the shell to extend into the groove, and it is beneficial to increase the welding area between the end of the shell and the groove wall of the groove, thereby improving the strength of 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, and increasing the service life of the battery cell.

[0021] In some embodiments, in a cross section perpendicular to an extension direction of the groove, a width of the groove is L1, wherein 0.6 mm ≤ L1 ≤ 1 mm.

[0022] By setting the width of the groove to 0.6 mm-1 mm, the connection structure between the shell and the top cover can have sufficient strength and is also conducive to the manufacturing and molding of the shell and the top cover.

[0023] In some embodiments, the height of the connecting side wall is H2, and the height of the cover body is H, wherein H-0.5mm≤H2≤13mm.

[0024] The connecting side wall within this height range can ensure that the connecting side wall and the outer shell have sufficient contact area. When the electrode assembly expands cyclically and generates gas during charging and discharging, and force is applied to the connection between the outer shell and the top cover, the connecting side wall will have sufficient limiting and supporting effects on the outer shell, thereby limiting the further outward deformation of the outer shell to a certain extent, reducing the risk of fatigue cracking of the connecting structure between the outer shell and the top cover, improving the problem of failure of the connecting structure between the outer shell and the top cover, and increasing the service life of the battery cell.

[0025] In some embodiments, the height of the connecting side wall is H2, and the height of the cover body is H, wherein H≤H2≤11 mm.

[0026] In some embodiments, the thickness of the connecting side wall is L2, wherein 0.2 mm ≤ L2 ≤ 1.5 mm.

[0027] In this embodiment, by setting the thickness of the connecting side wall to 0.2mm-1.5mm, the connecting side wall can have sufficient strength, thereby improving the structural strength of the connection between the top cover and the shell, and at the same time, the volume of the top cover can be reduced as much as possible, thereby improving the energy density of the battery cell.

[0028] In some embodiments, the thickness of the connecting section is L3, wherein 0.3 mm ≤ L3 ≤ 3 mm; or

[0029] In a cross section perpendicular to the extending direction of the groove, the width of the groove is L1, and the thickness of the connecting section is L3, wherein 0≤L1-L3≤0.3 mm.

[0030] By setting the thickness of the connecting section to 0.3mm-3mm, the connecting section can have sufficient strength, thereby improving the structural strength of the connection between the top cover and the shell, and at the same time, the volume of the top cover and the shell can be reduced as much as possible, thereby improving the energy density of the battery cell.

[0031] By setting the difference range of L1-L3 to 0-0.3mm, on the one hand, it is beneficial for the shell to extend into the groove, and on the other hand, it is beneficial for the connecting side wall to limit and support the shell when the shell is deformed outward, that is, it is beneficial to reduce the deformation of the shell or the degree of deformation.

[0032] In some embodiments, the outer side wall of the housing is formed with a step surface facing the top cover, and the end of the connecting side wall abuts against the step surface.

[0033] Here, on the one hand, the step surface can play a positioning role for the top cover, and together with the end surface of the outer shell, form a double positioning effect for the top cover, which is beneficial to improve the deformation of the top cover. On the other hand, it is also beneficial to increase the structural strength of the outer shell where the step surface is formed.

[0034] In some embodiments, a dimension of the step surface in the thickness direction of the shell is L4, wherein 0.1 mm ≤ L4 ≤ 0.5 mm.

[0035] By setting the size of the step surface in the thickness direction of the shell to 0.1mm-0.5mm, while achieving the positioning of the top cover, the volume of the shell and the molding materials can be reduced as much as possible, which is beneficial to reducing costs and improving the energy density of the battery cell.

[0036] In some embodiments, the groove extends along an edge of the top cover.

[0037] In this way, the force near the groove can be made more uniform.

[0038] In some embodiments, the battery cell is in a rectangular parallelepiped shape, and at least one long side of the top cover is provided with the groove; or,

[0039] When the battery cell is rectangular, the top cover and the outer shell are more likely to deform outward and crack at the large surface, that is, the connection structure between the top cover and the outer shell fails at the long side. Therefore, by providing a groove on the long side of the top cover, the problem of failure of the connection structure between the top cover and the outer shell can be effectively improved.

[0040] The battery cell is cylindrical in shape, and the groove is disposed on at least a portion of the top cover.

[0041] When the battery cell is cylindrical, the top cover may be provided with a circle of grooves extending along the edge of the top cover, or may be partially surrounded by grooves.

[0042] In some embodiments, the top cover and / or the housing are made of aluminum.

[0043] In some embodiments, the height of the cover body is H, wherein 1 mm ≤ H ≤ 5 mm.

[0044] By setting the height of the cover body to 1mm-5mm, the top cover 12 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.

[0045] In some embodiments, the height of the cover body is H, wherein 1.5 mm ≤ H ≤ 3 mm.

[0046] A second aspect of an embodiment of the present application provides a battery, comprising at least one battery cell as described above.

[0047] 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 sealing cover is arranged at the opening of the outer shell. By setting the top cover to include a cover body and a connecting side wall, and forming a groove between the cover body and the connecting side wall, during assembly, the end of the outer shell can be extended into the groove and connected to the top cover. Therefore, when the electrode assembly cyclically expands and gas is generated during charging and discharging, when force is applied to the connection between the outer shell and the top cover, the outer shell will deform outward, and the connecting side wall will limit and support the outer shell, thereby limiting the outer shell from further deforming outward to a certain extent, reducing the risk of fatigue cracking of the connection structure between the outer shell and the top cover, improving the problem of failure of the connection structure between the outer shell and the top cover, and increasing the service life of the battery cell.

[0048] 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.

[0049] The electrical device provided in the embodiment of the present application includes a battery, and the top cover sealing cover is arranged at the opening of the outer shell. By setting the top cover to include a cover body and a connecting side wall, and forming a groove between the cover body and the connecting side wall, during assembly, the end of the outer shell can be extended into the groove and connected to the top cover. As a result, when the electrode assembly cyclically expands and gas is generated during charging and discharging, when force is applied to the connection between the outer shell and the top cover, the outer shell will deform outward, and the connecting side wall will limit and support the outer shell, thereby limiting the outer shell from further deforming outward to a certain extent, reducing the risk of fatigue cracking of the connection structure between the outer shell and the top cover, improving the problem of failure of the connection structure between the outer shell and the top cover, and increasing the service life of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic diagram of the structure of a vehicle provided in one embodiment of the present application;

[0051] Figure 2 A three-dimensional exploded schematic diagram of a battery provided in one embodiment of the present application;

[0052] Figure 3 A top view of a battery cell provided in one embodiment of the present application;

[0053] Figure 4 for Figure 3 Section view in AA direction;

[0054] Figure 5 for Figure 4 The enlarged view of point B in the middle;

[0055] 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;

[0056] 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.

[0057] Description of Reference Numerals

[0058] 10. Battery cell; 11. Shell; 11a. Accommodation space; 11b. Opening; 11c. Main body section; 11d. Connecting section; 11e. Transition section; 11n. Step surface; 12. Top cover; 12a. Groove; 121. Cover body; 122. Connecting side wall; 20. Battery box; 21. First box body; 22. Second box body; 100. Battery; 200. Controller; 300. Motor; 1000. Vehicle. DETAILED DESCRIPTION

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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).

[0072] 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.

[0073] 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.).

[0074] Illustratively, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] In order to improve the problem of failure of the connection structure between the 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 a shell, a top cover and an electrode assembly. The shell has a receiving space and an opening. The top cover sealing cover is arranged at the opening. The electrode assembly is arranged in the receiving space. Among them, the top cover includes a cover body, a connecting side wall and a groove formed between the cover body and the connecting side wall, and the end of the shell extends into the groove and is connected to the top cover.

[0087] In the battery cell provided in the embodiment of the present application, the top cover sealing cover is arranged at the opening of the outer shell. By setting the top cover to include a cover body and a connecting side wall, and forming a groove between the cover body and the connecting side wall, during assembly, the end of the outer shell can be extended into the groove and connected to the top cover. As a result, when the electrode assembly cyclically expands and gas is generated during charging and discharging, when force is applied to the connection between the outer shell and the top cover, the outer shell will deform outward, and the connecting side wall will limit and support the outer shell, thereby limiting the outer shell from further deforming outward to a certain extent, reducing the risk of fatigue cracking of the connection structure between the outer shell and the top cover, improving the problem of failure of the connection structure between the outer shell and the top cover, and increasing the service life of the battery cell.

[0088] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] Figure 2 The battery 100 is a three-dimensional exploded schematic diagram of an embodiment of the present application. The battery 100 includes a battery box 20 and at least one battery cell 10 (not shown), and the battery cell 10 is disposed in the installation space of the battery box 20.

[0095] 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.

[0096] 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 one end open, the first box body 21 is a plate-like structure, and 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; the first box body 21 and the second box body 22 may also be a hollow structure with one side open, and the open 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.

[0097] 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 .

[0098] 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.

[0099] 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.

[0100] Exemplarily, the battery cell 10 may include a lithium-ion battery cell 10, a sodium-ion battery cell 10, or a magnesium-ion battery cell 10, 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.

[0101] The present application embodiment provides a battery cell 10. Figures 3 to 6 The battery cell 10 includes a housing 11, a top cover 12 and an electrode assembly. The housing 11 has a receiving 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 receiving space 11a. The top cover 12 includes a cover body 121, a connecting side wall 122 and a groove 12a formed between the cover body 121 and the connecting side wall 122, and the end of the housing 11 extends into the groove 12a and is connected to the top cover 12.

[0102] Here, the housing 11 may be cylindrical, flat, rectangular or in other shapes.

[0103] It should be noted that the height direction 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.

[0104] 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.

[0105] 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.

[0106] Here, the top cover 12 is provided with a cover body 121 and a connecting side wall 122, and a groove 12a is formed between the cover body 121 and the connecting side wall 122. On the one hand, when the top cover 12 and the shell 11 are assembled, the end of the shell 11 is first extended into the groove 12a of the top cover 12, and then the shell 11 is connected to the top cover 12, so that it is conducive to positioning the shell 11, thereby improving the assembly efficiency. On the other hand, when the electrode assembly cyclically expands and generates gas during charge and discharge, when a force is applied to the connection between the shell 11 and the top cover 12, the shell 11 will deform outwardly, and the top cover 12 limits the shell 11 between the cover body 121 and the connecting side wall 122 through the groove 12a, and the connecting side wall 122 will limit and support the shell 11, so that the shell 11 can be limited to a certain extent. The deformation of the shell 11 continues to be limited outward, thereby improving the structural strength of the connection between the top cover 12 and the shell 11, and reducing the risk of fatigue cracking of the connection structure between the shell 11 and the top cover 12.

[0107] In the battery cell 10 provided in the embodiment of the present application, the top cover 12 sealing cover is arranged at the opening 11b of the outer shell 11. By setting the top cover 12 to include a cover body 121 and a connecting side wall 122, and forming a groove 12a between the cover body 121 and the connecting side wall 122, during assembly, the end of the outer shell 11 can be extended into the groove 12a and connected to the top cover 12. Therefore, when the electrode assembly cyclically expands and gas is generated during charging and discharging, when force is applied to the connection between the outer shell 11 and the top cover 12, the outer shell 11 will deform outward, and the connecting side wall 122 will limit and support the outer shell 11, thereby limiting the outer shell 11 from further deforming outward to a certain extent, 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 increasing the service life of the battery cell 10.

[0108] 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.

[0109] In some embodiments, see Figures 3 to 6, the height of the top cover 12 at the groove 12a satisfies: the top cover 12 can be welded to the end of the housing 11 by penetration welding. In other words, the top cover 12 and the end of the housing 11 can be welded by laser from the outside of the top cover 12, and here, for example, the end of the housing 11 is welded to the side wall of the groove 12a in the height direction.

[0110] It is understandable that if the height of the top cover 12 at the groove 12a is too large, the laser welding efficiency or welding effect will be reduced. Therefore, the height of the top cover 12 at the groove 12a needs to be sufficient to achieve penetration welding between the top cover 12 and the end of the outer shell 11.

[0111] Of course, illustratively, the side wall of the shell 11 may be connected to the connecting side wall 122, or the side wall of the shell 11 may be connected to the connecting side wall 122 while the end of the shell 11 is welded to the groove wall of the groove 12a.

[0112] It should be noted that the specific structure of the housing 11 is not limited here.

[0113] In some embodiments, see Figure 5 The housing 11 includes a body section 11c and a connecting section 11d connected to the body section 11c. The connecting section 11d extends into the groove 12a and is connected to the top cover 12. The distance between the connecting section 11d and the central axis of the battery cell 10 is smaller than the distance between the body section 11c and the central axis of the battery cell 10.

[0114] Here, the distance between the connecting section 11d and the central axis of the battery cell 10 is smaller than the distance between the main section 11c and the central axis of the battery cell 10, that is, the connecting section 11d forms an opening 11b, and the housing 11 is contracted at the opening 11b.

[0115] In this embodiment, by setting the distance between the connecting section 11d and the central axis of the battery cell 10 to be smaller than the distance between the main body section 11c and the central axis of the battery cell 10, while the connecting section 11d is extended into the groove 12a and connected to the top cover 12, the main body section 11c is expanded outward as much as possible, thereby increasing the size of the accommodating space 11a, and further increasing the energy density of the battery cell 10.

[0116] In some embodiments, see Figure 5 The housing 11 includes a transition section 11e, the main body section 11c and the connecting section 11d are connected through the transition section 11e, the plane where the main body section 11c is located is parallel to the plane where the connecting section 11d is located, and along the direction from the main body section 11c to the connecting section 11d, the distance between the transition section 11e and the central axis of the battery cell 10 gradually decreases.

[0117] In this embodiment, the outer shell 11 is provided with a transition section 11e, and the distance between the transition section 11e and the central axis of the battery cell 10 gradually decreases along the direction from the main section 11c to the connecting section 11d, so that the size of the accommodating space 11a can be increased as much as possible, further improving the energy density of the battery cell 10.

[0118] In some embodiments, see Figure 5 and Figure 6 The height of the top cover 12 at the groove 12a is H1, wherein 0.2 mm ≤ H1 ≤ 1.5 mm, for example, 0.2 mm, 0.3 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm, etc.

[0119] The height of the top cover 12 at the groove 12a is the thickness of the groove wall of the top cover 12 at the groove 12a.

[0120] If the height dimension of the top cover 12 at the groove 12a is too large, the laser welding efficiency or welding effect will be reduced, and if the height dimension of the top cover 12 at the groove 12a is too small, the structural strength of the top cover 12 at the groove 12a will be reduced.

[0121] In this embodiment, by setting the height of the top cover 12 at the groove 12a to 0.2mm-1.5mm, the height of the top cover 12 at the groove 12a can meet the penetration welding between the top cover 12 and the end of the shell 11, and the top cover 12 can have sufficient structural strength at the groove 12a.

[0122] In some embodiments, see Figure 5 and Figure 6 The height of the top cover 12 at the groove 12a is H1, wherein 0.3 mm ≤ H1 ≤ 1 mm, for example, 0.3 mm, 0.4 mm, 0.7 mm, 0.9 mm or 1 mm.

[0123] In this embodiment, by setting the height of the top cover 12 at the groove 12a to 0.3mm-1mm, penetration welding between the top cover 12 and the end of the shell 11 can be facilitated, and the top cover 12 at the groove 12a can further have sufficient structural strength.

[0124] In some embodiments, see Figure 5 and Figure 6In a cross section perpendicular to the extending direction of the groove 12a, the width of the groove 12a is L1, wherein 0.4mm≤L1≤3.5mm, for example, 0.4mm, 0.5mm, 0.6mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.4mm or 3.5mm, etc.

[0125] Here, the width of the groove 12 a refers to the dimension of the groove 12 a in the thickness direction of the housing 11 .

[0126] It is understandable that the larger the width of the groove 12 a is, the more conducive it is to the assembly between the outer shell 11 and the top cover 12 , and the strength of the connection structure between the top end of the outer shell 11 and the top cover 12 .

[0127] In this embodiment, by setting the width of the groove 12a to 0.4mm-3.5mm, it is beneficial for the end of the shell 11 to extend into the groove 12a, and it is beneficial to increase the welding area between the end of the shell 11 and the groove wall of the groove 12a, thereby improving the strength of the connection structure between the shell 11 and the top cover 12, reducing the risk of cracking of the connection structure between the shell 11 and the top cover 12, and improving the service life of the battery cell 10.

[0128] In some embodiments, see Figure 5 and Figure 6 In a cross section perpendicular to the extending direction of the groove 12a, the width of the groove 12a is L1, wherein 0.6mm≤L1≤1mm, for example, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, etc.

[0129] In this embodiment, by setting the width of the groove 12 a to 0.6 mm-1 mm, the connection structure between the outer shell 11 and the top cover 12 can have sufficient strength and is also beneficial to the manufacturing and molding of the outer shell 11 and the top cover 12 .

[0130] In some embodiments, see Figure 5 and Figure 6 The height of the connecting side wall 122 is H2, and the height of the cover body is H, wherein H-0.5mm≤H2≤13mm. That is, the height of the connecting side wall 122 is greater than or equal to the height of the cover body minus 0.5mm, and less than or equal to 13mm.

[0131] The connecting side wall 122 within this height range can ensure that the connecting side wall 122 has a sufficient contact area with the outer shell 11. When the electrode assembly cyclically expands and generates gas during charging and discharging, and a force is applied to the connection between the outer shell 11 and the top cover 12, the connecting side wall 122 will have a sufficient limiting and supporting effect on the outer shell 11, thereby limiting the outer shell 11 from further deforming outward to a certain extent, reducing the risk of fatigue cracking of the connecting structure between the outer shell 11 and the top cover 12, improving the problem of failure of the connecting structure between the outer shell 11 and the top cover 12, and increasing the service life of the battery cell 10.

[0132] In some embodiments, see Figure 5 and Figure 6 The height of the connecting side wall 122 is H2, and the height of the cover body is H, wherein H≤H2≤11 mm. In other words, the height of the connecting side wall 122 is greater than or equal to the height of the cover body and less than or equal to 11 mm.

[0133] In this embodiment, the connecting side wall 122 within this height range can further ensure that the connecting side wall 122 has a sufficient contact area with the outer shell 11. When the electrode assembly cyclically expands and generates gas during charging and discharging, and a force is applied to the connection between the outer shell 11 and the top cover 12, the connecting side wall 122 can provide sufficient positioning and support for the outer shell 11, thereby limiting the outer shell 11 from further deforming outward to a certain extent, further reducing the risk of fatigue cracking of the connecting structure between the outer shell 11 and the top cover 12, improving the problem of failure of the connecting structure between the outer shell 11 and the top cover 12, and increasing the service life of the battery cell 10.

[0134] In some embodiments, see Figure 5 and Figure 6 The thickness of the connecting side wall 122 is L2, wherein 0.2 mm ≤ L2 ≤ 1.5 mm, for example, 0.2 mm, 0.4 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm, etc.

[0135] In this embodiment, by setting the thickness of the connecting side wall 122 to 0.2mm-1.5mm, the connecting side wall 122 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, the volume of the top cover 12 can be reduced as much as possible, thereby improving the energy density of the battery cell 10.

[0136] In some embodiments, see Figure 5 and Figure 6The thickness of the connecting side wall 122 is L2, wherein 0.3 mm ≤ L2 ≤ 1 mm, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 0.9 mm or 1 mm.

[0137] In this embodiment, by setting the thickness of the connecting side wall 122 to 0.3mm-1mm, the connecting side wall 122 can be further made to have sufficient strength, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and can also further reduce the volume of the top cover 12, thereby improving the energy density of the battery cell 10.

[0138] In some embodiments, see Figure 5 and Figure 6 The thickness of the connecting section 11d is L3, wherein 0.3mm≤L3≤3mm, for example, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.6mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm or 3mm, etc.

[0139] Here, the thickness of the connecting section 11 d is the thickness of the connection between the outer shell 11 and the top cover 12 , in other words, the thickness of the area where the outer shell 11 extends into the groove 12 a .

[0140] In this embodiment, by setting the thickness of the connecting section 11d to 0.3mm-3mm, the connecting section 11d 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, the volume of the top cover 12 and the outer shell 11 can be reduced as much as possible, thereby improving the energy density of the battery cell 10.

[0141] In some embodiments, see Figure 5 and Figure 6 In a cross section perpendicular to the extending direction of the groove 12a, the width of the groove 12a is L1, and the thickness of the connecting section 11d is L3, wherein 0≤L1-L3≤0.3mm, for example, 0, 0.1mm, 0.15mm, 0.2mm, 0.25mm or 0.3mm, etc.

[0142] By setting the difference range of L1-L3 to 0-0.3mm, on the one hand, it is beneficial for the shell 11 to extend into the groove 12a, and on the other hand, it is beneficial for the connecting side wall 122 to limit and support the shell 11 when the shell 11 is deformed outward, that is, it is beneficial to reduce the deformation of the shell 11 or the degree of deformation.

[0143] In some embodiments, see Figure 5 and Figure 6 The outer wall of the housing 11 is formed with a step surface 11n facing the top cover 12, and the end of the connecting side wall 122 abuts against the step surface 11n.

[0144] Here, on the one hand, the step surface 11n can play a positioning role for the top cover 12, and together with the end surface of the outer shell 11, form a double positioning effect for the top cover 12, which is beneficial to improve the deformation of the top cover 12. On the other hand, it is also beneficial to increase the structural strength of the outer shell 11 at the point where the step surface 11n is formed.

[0145] In some embodiments, see Figure 5 and Figure 6 The dimension of the step surface 11n in the thickness direction of the housing 11 is L4, wherein 0.1≤L4≤0.5mm, for example, 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm, etc.

[0146] Here, the dimension of the step surface 11 n in the thickness direction of the housing 11 is the distance that the step surface 11 n extends outward along the outer side wall of the housing 11 .

[0147] In this embodiment, by setting the dimension of the step surface 11n in the thickness direction of the shell 11 to 0.1mm-0.5mm, while achieving the positioning of the top cover 12, the volume of the shell 11 and the molding material can be reduced as much as possible, which is beneficial to reducing costs and improving the energy density of the battery cell 10.

[0148] It should be noted that the extending direction of the groove 12a is not limited here.

[0149] In some embodiments, see Figure 5 and Figure 6 , the groove 12 a extends along the edge of the top cover 12 .

[0150] Here, the groove 12 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 12 a along the extension direction is completely or substantially the same as the contour shape of the top cover 12 .

[0151] It can be understood that the groove 12a extends along the edge of the top cover 12, so that the distances between any two positions of the groove 12a in its extension direction and the edge of the top cover 12 are the same, that is, the distances between any two positions of the groove 12a in its extension direction and the outer wall connected to the side wall 122 are the same, so that the force near the groove 12a can be made more uniform.

[0152] It should be noted that the top cover 12 may be formed with the groove 12a in a partial area between the cover body 121 and the connecting side wall 122, or may be formed with the groove 12a 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 12a 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.

[0153] In some embodiments, the battery cell 10 is cylindrical, and at least a portion of the top cover 12 is provided with a groove 12 a.

[0154] For example, when the battery cell 10 is cylindrical, the top cover 12 may be provided with a circle of grooves 12 a extending along the edge of the top cover 12 , or may be partially surrounded by the grooves 12 a .

[0155] In some embodiments, the battery cell 10 is in a rectangular parallelepiped shape, and at least one long side of the top cover 12 is provided with a groove 12 a.

[0156] Here, the groove 12 a may be provided on one of the long sides of the top cover 12 , or may be provided on both long sides of the top cover 12 .

[0157] When the battery cell 10 is rectangular, the top cover 12 and the outer shell 11 are more likely to deform outward and crack at the large surface, that is, the connection structure between the top cover 12 and the outer shell 11 at the long side fails. Therefore, by providing a groove 12a on the long side of the top cover 12, the problem of failure of the connection structure between the top cover 12 and the outer shell 11 can be effectively improved.

[0158] The groove 12a 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 12a corresponding to the contour of the top cover 12 .

[0159] In some embodiments, the top cover 12 and / or the housing 11 are made of aluminum.

[0160] It can be understood that when the material of the top cover 12 and / or the outer shell 11 is aluminum, by forming a groove 12a between the cover body 121 and the connecting side wall 122, during assembly, the end of the outer shell 11 can be extended into the groove 12a and connected to the top cover 12. As a result, when the electrode assembly cyclically expands and generates gas during charging and discharging, when force is applied to the connection between the outer shell 11 and the top cover 12, the outer shell 11 will deform outward, and the connecting side wall 122 will limit and support the outer shell 11, thereby limiting the outer shell 11 from further deforming outward to a certain extent, 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 increasing the service life of the battery cell 10.

[0161] In some embodiments, see Figure 5 and Figure 6 The height of the cover body 121 is H, wherein 1 mm ≤ H ≤ 5 mm, for example, 1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.8 mm, 2 mm, 3 mm, 3.4 mm, 3.5 mm, 3.7 mm, 4 mm, 4.4 mm, 4.5 mm, 4.7 mm or 5 mm, etc.

[0162] In this embodiment, by setting the height of the cover body 121 to 1mm-5mm, the top cover 1212 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.

[0163] In some other embodiments, please refer to Figure 5 and Figure 6 The height of the cover body 121 is H, wherein 1.5 mm ≤ H ≤ 3 mm, for example, 1.5 mm, 1.7 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.

[0164] 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.

[0165] It should be noted that the height H of the cover body, the height H1 of the top cover 12 at the groove 12a, the height H2 of the connecting side wall 122, the width L1 of the groove 12a, the thickness L2 of the connecting side wall 122, the thickness L3 of the connecting section 11d, the dimension L4 of the step surface 11n in the thickness direction of the outer shell 11 and other values ​​can be obtained by testing and calculation using instruments such as a high-precision thickness gauge and a vernier caliper at room temperature when the top cover 12 is not assembled.

[0166] The battery cell 10 of the present application is further described below in conjunction with specific test examples.

[0167] The test sample of the embodiment of the present application: the top cover 12 includes a cover body 121 and a connecting piece, the cover body 121 has a channel penetrating the cover body 121, and the connecting piece is arranged on a side of the cover body 121 close to the electrode assembly and closes the channel.

[0168] By carrying out charge and discharge cycle experiments on the test samples of the embodiment of the present application and the control group, 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, the average number of cycles of the five test samples of the embodiment of the present application is 3209 times, the number of cycles of the five test samples of the control group are 3916, 3852, 3733, 3949, and 3871, respectively, and the average number of cycles of the five test samples of the embodiment of the present application is 3864 times. The average value of the test samples of the embodiment of the present application is 20.4% higher than that of the control group. When the electrode assembly cyclically expands and generates gas during charge and discharge, force is generated at 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 that 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, and increases the service life of the battery cell 10.

[0169] 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.

[0170] 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; The top cover comprises a cover body, a connecting side wall and a groove formed between the cover body and the connecting side wall, and the end of the shell extends into the groove and is connected to the top cover.

2. The battery cell according to claim 1, characterized in that: The housing includes a main body section and a connecting section connected to the main body section, the connecting section extends into the groove and is connected to the top cover, and the distance between the connecting section and the central axis of the battery cell is smaller than the distance between the main body section and the central axis of the battery cell.

3. The battery cell according to claim 1, characterized in that: The shell includes a transition section, the main body section and the connecting section are connected by the transition section, the plane where the main body section is located is parallel to the plane where the connecting section is located, and along the direction from the main body section to the connecting section, the distance between the transition section and the central axis of the battery cell gradually decreases.

4. The battery cell according to claim 1, characterized in that: The height of the top cover at the groove is H1, wherein 0.2 mm ≤ H1 ≤ 1.5 mm; and / or, In a cross section perpendicular to the extending direction of the groove, the width of the groove is L1, wherein 0.4 mm≤L1≤3.5 mm.

5. The battery cell according to claim 1, characterized in that: The height of the top cover at the groove is H1, wherein 0.3 mm ≤ H1 ≤ 1 mm; and / or, In a cross section perpendicular to the extending direction of the groove, the width of the groove is L1, wherein 0.6 mm≤L1≤1 mm.

6. The battery cell according to claim 1, characterized in that: The height of the connecting side wall is H2, and the height of the cover body is H, wherein H-0.5mm≤H2≤13mm; and / or, The thickness of the connecting side wall is L2, wherein 0.2 mm ≤ L2 ≤ 1.5 mm.

7. The battery cell according to claim 3, characterized in that: The thickness of the connecting section is L3, wherein 0.3 mm ≤ L3 ≤ 3 mm; or In a cross section perpendicular to the extending direction of the groove, the width of the groove is L1, and the thickness of the connecting section is L3, wherein 0≤L1-L3≤0.3 mm.

8. The battery cell according to claim 1, characterized in that: The outer side wall of the shell is formed with a step surface facing the top cover, and the end of the connecting side wall abuts against the step surface.

9. The battery cell according to claim 8, characterized in that: The dimension of the step surface in the thickness direction of the shell is L4, wherein 0.1 mm≤L4≤0.5 mm.

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

11. The battery cell according to any one of claims 4 to 10, characterized in that: The top cover and / or the housing are made of aluminum.

12. The battery cell according to any one of claims 4 to 10, characterized in that: The battery cell is in a rectangular parallelepiped shape, and at least one long side of the top cover is provided with the groove; or, The battery cell is cylindrical in shape, and the groove is disposed on at least a portion of the top cover.

13. The battery cell according to any one of claims 1 to 3, characterized in that: The height of the cover body is H, wherein 1 mm≤H≤5 mm.

14. A battery, characterized in that: The invention comprises at least one battery cell according to any one of claims 1 to 13.

15. An electrical device, characterized in that: The battery according to claim 14 is used to provide electrical energy to the electrical device.

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