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 shell is provided with a containing 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 main body, a connecting side wall is formed in at least partial area of the peripheral side of the cover main body, the connecting side wall is connected with the shell, and the size of at least the area, connected with the connecting side wall, of the cover main body in the height direction of the battery monomers is smaller than that of the connecting side wall in the height direction of the battery monomers. According to the battery monomer provided by the embodiment of the invention, the stress of the connecting structure between the shell and the top cover can be reduced, 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 production process of battery cells, after placing the bare cell into the shell and closing the top cover, a cell with a shell 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 shell and a top cover, wherein the shell has a containing space and an opening, and the top cover sealing cover is arranged at the opening;

[0007] An electrode assembly is disposed in the accommodation space;

[0008] Among them, the top cover has a cover body, and a connecting side wall is formed in at least a partial area of ​​the circumference of the cover body, and the connecting side wall is connected to the outer shell. The size of at least the area where the cover body is connected to the connecting side wall in the height direction of the battery cell is smaller than the size of the connecting side wall in the height direction of the battery cell.

[0009] In the battery cell provided by the embodiment of the present application, the top cover sealing cover is arranged at the opening of the shell, the top cover has a cover body, and a connecting side wall is arranged on the peripheral side of the cover body for connecting with the shell, and the size of the area where the cover body is at least connected to the connecting side wall in the height direction of the battery cell is set to be smaller than the size of the connecting side wall in the height direction of the battery cell, that is, it can be equivalent to increasing the contact area and connection area between the top cover and the shell, thereby improving the structural strength of the connection between the top cover and the shell, and by increasing the height of the connecting side wall, the shear resistance (also called shear strength) of the connection between the shell and the top cover is improved, that is, the maximum stress value that the connection between the shell and the top cover can bear under the action of shear force is improved. It can also be equivalent to thinning the connection between the connecting side wall and the cover body, and when the electrode assembly expands cyclically and generates gas during charge and discharge, the groove between the connecting side wall and the cover body 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.

[0010] In some embodiments, a groove is formed between the cover body and the connecting side wall.

[0011] By forming a groove at the connection between the side wall and the cover body, that is, thinning the connection between the side wall and the cover body, when the electrode assembly expands cyclically and generates gas during charge and discharge, and when force is applied to the connection between the outer shell and the top cover, the groove between the side wall and the cover body forms a force buffer zone at the connection between the outer shell and the top cover, thereby reducing the force on the connection structure between the outer shell and the top cover, reducing the risk of 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.

[0012] In some embodiments, a dimension of the connecting side wall in a height direction of the battery cell is greater than a dimension of the cover body in the height direction of the battery cell.

[0013] In this embodiment, the connecting side wall is connected to the outer shell, and the height of the connecting side wall is set to be greater than the height of the cover body, which is equivalent to increasing the contact area and connection area between the top cover and the outer shell, thereby improving the structural strength of the connection between the top cover and the outer shell, and by increasing the height of the connecting side wall, the shear resistance (also called shear strength) of the connection between the outer shell and the top cover is improved, that is, the maximum stress value that the connection between the outer shell and the top cover can bear under the action of shear force is improved.

[0014] In some embodiments, an end surface of the connecting side wall is flush with an end surface of the housing.

[0015] While increasing the height of the connecting side wall as much as possible and increasing the contact area and connection area between the top cover and the shell, the structure of the battery cell is made compact and the volume of the battery cell is reduced as much as possible, thereby improving the performance of the battery.

[0016] In some embodiments, the height of the connecting side wall is H1, and the height of the cover body is H2, wherein H2≤H1≤4H2.

[0017] The top cover and the outer shell can have sufficient contact area and connection area, thereby improving the structural strength of the connection between the top cover and the outer shell, and by increasing the height of the connecting side wall, the shear resistance of the connection between the outer shell and the top cover is improved, that is, the maximum stress value that the connection between the outer shell and the top cover can bear under the action of shear force is increased, and at the same time, the structure of the battery cell can be made compact and the volume of the battery cell can be reduced as much as possible, thereby improving the performance of the battery.

[0018] In some embodiments, the height of the connecting side wall is H1, and the height of the cover body is H2, wherein H2≤H1≤3H2.

[0019] In some embodiments, the thickness of the connecting side wall is L1, and the thickness of the connection portion between the outer shell and the connecting side wall is L2, wherein L2≤L1≤6L2.

[0020] In this embodiment, by setting the thickness of the connecting side wall to L2-6L2, the connecting side wall can have sufficient strength, thereby improving the structural strength of the connection between the top cover and the outer shell, and the groove on the top cover can be set as close to the outer shell as possible, which is more conducive to the force of the connection between the outer shell and the top cover being transmitted to the groove, thereby facilitating the deformation to be concentrated at the groove, thereby reducing the force on the connection structure between the outer shell and the top cover, reducing the risk of 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.

[0021] In some embodiments, the thickness of the connecting side wall is L1, and the thickness of the connection portion between the outer shell and the connecting side wall is L2, wherein 1.2L2≤L1≤3L2.

[0022] In some embodiments, in a cross section perpendicular to an extension direction of the groove, a width of the groove is L3, wherein 0.4 mm ≤ L3 ≤ 10 mm.

[0023] In this embodiment, by setting the width of the groove to 0.4mm-10mm, the top cover can have sufficient strength, and it is also beneficial to transfer the force at the connection between the outer shell and the top cover to the groove, which is more conducive to concentrating the deformation at the groove, thereby reducing the force on the connection structure between the outer shell and the top cover, reducing the risk of cracking of the connection structure between the outer shell and the top cover, and improving the service life of the top cover.

[0024] In some embodiments, in a cross section perpendicular to an extension direction of the groove, a width of the groove is L3, wherein 0.5 mm≤L3≤5 mm.

[0025] In some embodiments, the height of the top cover at the groove is H3, the height of the cover body is H2, and the thickness of the connection between the shell and the connecting side wall is L2, wherein L2≤H3<H2.

[0026] In this embodiment, by setting the height of the top cover at the groove to L2-H2, the top cover can have sufficient strength at the groove and sufficient deformation capacity at the groove.

[0027] In some embodiments, the height of the top cover at the groove is H3, the height of the cover body is H2, and the thickness of the connection between the shell and the connecting side wall is L2, wherein:

[0028] In some embodiments, the height of the cover body is H2, wherein 1mm≤H2≤5mm; and / or the thickness of the connection between the shell and the connecting side wall is L2, wherein 0.4mm≤L2≤2mm.

[0029] In this embodiment, 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.

[0030] 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.

[0031] In some embodiments, the height of the cover body is H2, wherein 1.5 mm ≤ H2 ≤ 3 mm; and / or the thickness of the connection between the shell and the connecting side wall is L2, wherein 0.6 mm ≤ L2 ≤ 1.7 mm.

[0032] In some embodiments, a circle of the connecting side wall surrounds the circumference of the cover body.

[0033] Here, the peripheral sides of the top cover are connected to the outer shell through connecting side walls, and a circle of grooves is formed on the top cover, so that it is more conducive to transmitting the force at the connection between the outer shell and the top cover to the groove.

[0034] A second aspect of an embodiment of the present application provides a battery, comprising at least one battery cell as described above.

[0035] 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 of the battery cell is arranged at the opening of the outer shell, and the top cover has a cover body, which is used to connect with the outer shell by arranging a connecting side wall on the peripheral side of the cover body, and by setting the dimension of the area where the cover body is at least connected to the connecting side wall in the height direction of the battery cell to be smaller than the dimension of the connecting side wall in the height direction of the battery cell, that is, it can be equivalent to increasing the contact area and connection area between the top cover and the outer shell, thereby improving the structural strength of the connection between the top cover and the outer shell, and by increasing the height of the connecting side wall, the shear resistance (also called shear strength) of the connection between the outer shell and the top cover is improved, that is, the maximum stress value that the connection between the outer shell and the top cover can bear under the action of shear force is improved. It can also be equivalent to thinning the connection between the side wall and the cover body. In this way, when the electrode assembly expands cyclically and generates gas during charging and discharging, which exerts force on the connection between the outer shell and the top cover, the groove between the side wall and the cover body forms a force buffer zone at the connection between the outer shell and the top cover, thereby reducing the force on the connection structure between the outer shell and the top cover, reducing the risk of 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.

[0036] 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.

[0037] The electrical device provided in the embodiment of the present application includes a battery, and the battery includes at least one battery cell of the embodiment of the present application. The top cover sealing cover of the battery cell is arranged at the opening of the outer shell, and the top cover has a cover body, which is used to connect with the outer shell by arranging a connecting side wall on the peripheral side of the cover body, and the dimension of the area where the cover body is at least connected to the connecting side wall in the height direction of the battery cell is set to be smaller than the dimension of the connecting side wall in the height direction of the battery cell, that is, it can be equivalent to increasing the contact area and connection area between the top cover and the outer shell, thereby improving the structural strength of the connection between the top cover and the outer shell, and by increasing the height of the connecting side wall, the shear resistance (also called shear strength) of the connection between the outer shell and the top cover is improved, that is, the maximum stress value that the connection between the outer shell and the top cover can bear under the action of shear force is improved. It can also be equivalent to thinning the connection between the side wall and the cover body. In this way, when the electrode assembly expands cyclically and generates gas during charging and discharging, which exerts force on the connection between the outer shell and the top cover, the groove between the side wall and the cover body forms a force buffer zone at the connection between the outer shell and the top cover, thereby reducing the force on the connection structure between the outer shell and the top cover, reducing the risk of 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

[0038] Figure 1 A schematic diagram of the structure of a vehicle provided in one embodiment of the present application;

[0039] Figure 2 A three-dimensional exploded schematic diagram of a battery provided in one embodiment of the present application;

[0040] Figure 3 A top view of a battery cell provided in one embodiment of the present application;

[0041] Figure 4 An exploded view of a battery cell provided in an embodiment of the present application, wherein the electrode assembly is omitted;

[0042] Figure 5 for Figure 4 The enlarged view of point B in the middle;

[0043] Figure 6 for Figure 3 Section view in AA direction;

[0044] Figure 7 for Figure 6 Enlarged view of point C in the middle;

[0045] Figure 8 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;

[0046] Fig. 9The 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.

[0047] Description of Reference Numerals

[0048] 10. Battery cell; 11. Shell; 11a. Accommodation space; 11b. Opening; 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

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] For related technologies, see Fig. 9 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.

[0064] 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, and the top cover sealing cover is arranged at the opening. The electrode assembly is arranged in the accommodating space. Among them, the top cover has a cover body, and at least a part of the area around the cover body is formed with a connecting side wall, and the connecting side wall is connected to the outer shell, and the size of the cover body at least in the area where the connecting side wall is connected in the height direction of the battery cell is smaller than the size of the connecting side wall in the height direction of the battery cell.

[0065] In the battery cell provided by the embodiment of the present application, the top cover sealing cover is arranged at the opening of the shell, the top cover has a cover body, and a connecting side wall is arranged on the peripheral side of the cover body for connecting with the shell, and the size of the area where the cover body is at least connected to the connecting side wall in the height direction of the battery cell is set to be smaller than the size of the connecting side wall in the height direction of the battery cell, that is, it can be equivalent to increasing the contact area and connection area between the top cover and the shell, thereby improving the structural strength of the connection between the top cover and the shell, and by increasing the height of the connecting side wall, the shear resistance (also called shear strength) of the connection between the shell and the top cover is improved, that is, the maximum stress value that the connection between the shell and the top cover can bear under the action of shear force is improved. It can also be equivalent to thinning the connection between the connecting side wall and the cover body, so that when the electrode assembly expands cyclically and generates gas during charge and discharge, the groove between the connecting side wall and the cover body 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.

[0066] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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 hybrid connection, and hybrid connection means that a plurality of battery cells 10 are both connected in series and in parallel. A plurality of battery cells 10 may be directly connected in series, in parallel or in hybrid connection, and then the whole formed by the plurality of battery cells 10 is accommodated in the box; of course, the battery 100 may also be a plurality of battery cells 10 connected in series, in parallel or in hybrid connection to form a battery 100 module, and a plurality of battery 100 modules are then connected in series, in parallel or in hybrid connection to form a whole, and are accommodated 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. Among them, each battery cell 10 may be a secondary battery 100 or a primary battery 100; it may also be a lithium-sulfur battery 100, a sodium-ion battery 100 or a magnesium-ion battery 100, but is not limited thereto. The battery cell 10 may be cylindrical, flat, rectangular or in other shapes.

[0072] Figure 2 The exploded schematic diagram of a battery 100 provided in one 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.

[0073] 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.

[0074] 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.

[0075] 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 .

[0076] 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.

[0077] 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.

[0078] 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.

[0079] The present application embodiment provides a battery cell 10. Figures 3 to 7 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, and 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 has a cover body 121, and a connecting side wall 122 is formed on at least part of the area around the cover body 121. The connecting side wall 122 is connected to the shell 11, and the size of at least the area where the cover body 121 is connected to the connecting side wall 122 in the height direction of the battery cell 10 is smaller than the size of the connecting side wall 122 in the height direction of the battery cell 10.

[0080] Here, the housing 11 may be cylindrical, flat, rectangular or in other shapes.

[0081] It should be noted that the height direction described in the embodiment of the present application is the direction from the opening 11 b into the accommodating space 11 a. When the housing 11 is cylindrical, the height direction of the housing 11 is the axial direction of the housing 11.

[0082] There are various ways in which the dimension of at least the region where the cover body is connected to the connecting side wall in the height direction of the battery cell is smaller than the dimension of the connecting side wall in the height direction of the battery cell.

[0083] Exemplarily, a groove is formed between the cover body 121 and the connecting side wall 122 .

[0084] Here, a groove 12 a is formed between the connecting side wall 122 and the cover body 121 , and the connecting side wall 122 is connected to the housing 11 , that is, a side of the connecting side wall 122 facing away from the groove 12 a is connected to the housing 11 .

[0085] It should be noted that the specific method of connecting the side wall 122 and the housing 11 is not limited here, for example, welding.

[0086] The connection side wall 122 is formed at least partially around the circumference of the cover body 121 , which means that the connection side wall 122 may be formed partially around the circumference of the cover body 121 , or may be formed all around the circumference of the cover body 121 .

[0087] In an embodiment in which a connecting side wall 122 is formed in a partial area around the cover body 121, the top cover 12 can be connected to the outer shell 11 through the connecting side wall 122 in the area where the connecting side wall 122 is formed, and can be connected to the outer shell 11 through the cover body 121 in the area where the connecting side wall 122 is not formed.

[0088] In the embodiment where the connecting side wall 122 is formed on the entire circumference of the cover body 121 , the top cover 12 is connected to the housing 11 via the connecting side wall 122 .

[0089] Exemplarily, when the housing 11 is cylindrical, the circumference of the cover body 121 may be surrounded by a circle of connecting side walls 122 , or may be partially surrounded by connecting side walls 122 .

[0090] When the housing 11 is in a rectangular parallelepiped shape, the connecting side wall 122 may be formed partially or entirely on the long sides, or partially or entirely on the short sides. In some embodiments, the connecting side wall 122 is formed on all sides of the cover body 121. In other embodiments, the connecting side walls 122 are formed on the two long sides of the cover body 121, and the connecting side walls 122 are not formed on the two short sides.

[0091] 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.

[0092] 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 peripheral side of the cover body 121. The split cover body 121 and the connecting side wall 122 are conducive to molding.

[0093] It should be noted that the specific shape of the groove 12a is not limited here. For example, in the cross section perpendicular to the extension direction of the groove 12a, the cross-sectional shape of the groove 12a is polygonal, circular or elliptical.

[0094] It can be understood that a groove 12a is formed between the connecting side wall 122 and the cover body 121, that is, the connection between the connecting side wall 122 and the cover body 121 is formed by a depression to form the groove 12a, and the wall thickness of the top cover 12 at the groove 12a is less than the wall thickness of the cover body 121, thereby weakening the strength of the top cover 12 at the groove 12a. Therefore, when the connection between the outer shell 11 and the top cover 12 is acted upon by a force, the force is more likely to act on the groove 12a of the top cover 12. In other words, the position of the top cover 12 at the groove 12a is equivalent to forming a force buffer zone at the connection between the outer shell 11 and the top cover 12.

[0095] The top cover 12 is generally perpendicular to the side of the outer shell 11. The outer shell 11 deforms outward, and a shear force parallel to the top cover 12 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 charge and discharge, the outer shell 11 is subjected to force, so that the deformation is concentrated at the groove 12a of the top cover 12 (see Figure 8 ), 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 increasing the service life of the battery cell 10.

[0096] 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, and the top cover 12 has a cover body 121, and is used to connect with the outer shell 11 by arranging a connecting side wall 122 on the peripheral side of the cover body 121, and by setting the dimension of the area where the cover body 121 is at least connected to the connecting side wall 122 in the height direction of the battery cell 10 to be smaller than the dimension of the connecting side wall 122 in the height direction of the battery cell 10, that is, it can be equivalent to increasing the contact area and connection area between the top cover 12 and the outer shell 11, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and by increasing the height of the connecting side wall 122, the shear resistance (also called shear strength) of the connection between the outer shell 11 and the top cover 12 is improved, that is, 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 is improved. It can also be equivalent to thinning the connection between the side wall 122 and the cover body 121. In this way, 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 groove 12a between the side wall 122 and the cover body 121 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.

[0097] In some embodiments, see Figure 5 and Figure 7 , a dimension of the connecting side wall 122 in the height direction of the battery cell 10 is greater than a dimension of the cover body 121 in the height direction of the battery cell 10 .

[0098] Here, the dimension of the connecting side wall 122 in the height direction of the battery cell 10 is greater than the dimension of the cover body 121 in the height direction of the battery cell 10 means that the height of the connecting side wall 122 is greater than the height of the cover body 121 .

[0099] In this embodiment, the connecting side wall 122 is connected to the outer shell 11. By setting the height of the connecting side wall 122 to be greater than the height of the cover body 121, it is equivalent to increasing the contact area and connection area between the top cover 12 and the outer shell 11, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and by increasing the height of the connecting side wall 122, the shear resistance (also called shear strength) of the connection between the outer shell 11 and the top cover 12 is improved, that is, 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 is improved.

[0100] In some embodiments, see Figure 7 , the end surface of the connecting side wall 122 is flush with the end surface of the housing 11.

[0101] Here, the end surface of the connecting side wall 122 being flush with the end surface of the housing 11 means that the end surface of the connecting side wall 122 and the end surface of the housing 11 are substantially in the same plane or completely in the same plane.

[0102] In this embodiment, by setting the end face of the connecting side wall 122 to be flush with the end face of the outer shell 11, the height of the connecting side wall 122 is increased as much as possible, the contact area and connection area between the top cover 12 and the outer shell 11 are increased, and the structure of the battery cell 10 is made compact and the volume of the battery cell 10 is reduced as much as possible, thereby improving the performance of the battery 100.

[0103] In some embodiments, see Figure 6 and Figure 7 The height of the cover body 121 is H2, wherein 1mm≤H2≤5mm, for example, 1mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, 2mm, 3mm, 3.3mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm or 5mm, etc.

[0104] 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.

[0105] In some other embodiments, please refer to Figure 6 and Figure 7 The height of the cover body 121 is H2, wherein 1.5 mm ≤ H2 ≤ 3 mm, for example, 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.3 mm, 2.5 mm, 2.7 mm, 2.8 mm, 2.9 mm or 3 mm.

[0106] 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.

[0107] In some embodiments, please refer to Figure 6 and Figure 7The thickness of the connection between the housing 11 and the connecting side wall 122 is L2, wherein 0.4 mm ≤ L2 ≤ 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, etc.

[0108] The thickness of the connection between the shell 11 and the connecting side wall 122 is L2, that is, the thickness of the shell 11 near the opening 11b is L2.

[0109] It should be noted that the housing 11 may include regions with different thicknesses. For example, along the height direction of the housing 11, the housing 11 includes a first region close to one end of the opening 11b and a second region away from one end of the opening 11b, that is, the thickness of the first region is L2. The thickness of the first region is different from the thickness of the second region.

[0110] Exemplarily, the thickness of the first region is greater than that of the second region. Since the first region is close to one end of the opening 11b, the top cover 12 is connected to the first region, and by setting the thickness of the first region to be greater than that of the second region, the connection strength of the top cover 12 and the housing 11 can be improved.

[0111] It should be noted that the height of the first area is not limited here, and at least needs to be connected to the top cover 12. Exemplarily, the height of the first area is not less than 10 mm.

[0112] 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.

[0113] For other embodiments, please refer to Figure 6 and Figure 7 The thickness of the connection between the housing 11 and the connecting side wall 122 is L2, wherein 0.6 mm ≤ L2 ≤ 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.

[0114] 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.

[0115] In some embodiments, please refer to Figure 6 and Figure 7 The height of the connecting side wall 122 is H1, and the height of the cover body 121 is H2, wherein H2≤H1≤4H2. That is, the height of the connecting side wall 122 is greater than or equal to the height of the cover body 121, and less than or equal to 4 times the height of the cover body 121.

[0116] H1 is, for example, 1H2, 1.2H2, 1.4H2, 1.5H2, 1.8H2, 2H2, 2.5H2, 3H2, 3.3H2, 3.5H2, 3.6H2, 3.7H2, 3.8H2, 3.9H2 or 4H2, etc.

[0117] In this embodiment, by setting the height of the connecting side wall 122 to H2-4H2, the top cover 12 and the outer shell 11 can have sufficient contact area and connection area, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and by increasing the height of the connecting side wall 122, the shear resistance of the connection between the outer shell 11 and the top cover 12 is improved, that is, 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 is increased, and at the same time, the structure of the battery cell 10 can be made compact, and the volume of the battery cell 10 can be reduced as much as possible, thereby improving the performance of the battery 100.

[0118] In some other embodiments, please refer to Figure 6 and Figure 7 The height of the connecting side wall 122 is H1, and the height of the cover body 121 is H2, wherein H2≤H1≤3H2. In other words, the height of the connecting side wall 122 is greater than or equal to the height of the cover body 121, and less than or equal to 3 times the height of the cover body 121.

[0119] In this embodiment, by setting the height of the connecting side wall 122 to H2-3H2, the top cover 12 and the outer shell 11 can have sufficient contact area and connection area, thereby improving the structural strength of the connection between the top cover 12 and the outer shell 11, and by increasing the height of the connecting side wall 122, the shear resistance of the connection between the outer shell 11 and the top cover 12 is improved, that is, 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 is increased, and the structure of the battery cell 10 can be further made compact, and the volume of the battery cell 10 can be reduced as much as possible, thereby further improving the performance of the battery 100.

[0120] In some embodiments, see Figure 6 and Figure 7, the thickness of the connecting side wall 122 is L1, and the thickness of the connection between the shell 11 and the connecting side wall 122 is L2, wherein L2≤L1≤6L2. In other words, the thickness of the connecting side wall 122 is greater than or equal to the thickness of the connection between the shell 11 and the connecting side wall 122, and less than or equal to 6 times the thickness of the connection between the shell 11 and the connecting side wall 122.

[0121] Here, the thickness of the connection between the housing 11 and the connecting side wall 122 is the thickness of the first region.

[0122] L1 is, for example, 1L2, 1.2L2, 1.5L2, 1.8L2, 2L2, 2.5L2, 3L2, 3.3L2, 3.5L2, 3.6L2, 3.7L2, 3.8L2, 3.9L2, 4L2, 4.2L2, 4.5L2, 4.7L2, 4.9L2, 5L2, 5.3L2, 5.6L2, 5.8L2 or 6L2, etc.

[0123] In this embodiment, by setting the thickness of the connecting side wall 122 to L2-6L2, 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 the groove 12a on the top cover 12 can be set as close to the outer shell 11 as possible, which is more conducive to the force at the connection between the outer shell 11 and the top cover 12 being transmitted to the groove 12a, thereby facilitating the deformation to be concentrated at the groove 12a, 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.

[0124] In some other embodiments, please refer to Figure 6 and Figure 7 , the thickness of the connecting side wall 122 is L1, and the thickness of the connection between the shell 11 and the connecting side wall 122 is L2, wherein 1.2L2≤L1≤3L2. In other words, the thickness of the connecting side wall 122 is greater than or equal to 1.2 times the thickness of the connection between the shell 11 and the connecting side wall 122, and less than or equal to 6 times the thickness of the connection between the shell 11 and the connecting side wall 122.

[0125] L1 is, for example, 1.2L2, 1.3L2, 1.4L2, 1.5L2, 1.6L2, 1.7L2, 1.8L2, 2L2, 2.1L2, 2.2L2, 2.4L2, 2.5L2, 2.6L2, 2.7L2, 2.8L2, 2.9L2 or 3L2, etc.

[0126] In this embodiment, by setting the thickness of the connecting side wall 122 to 1.2L2-3L2, 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 can further make the groove 12a on the top cover 12 close to the outer shell 11, which is further beneficial to the force of the connection between the outer shell 11 and the top cover 12 to be transmitted to the groove 12a, thereby reducing the risk of cracking of the connection structure between the outer shell 11 and the top cover 12.

[0127] In some embodiments, see Figure 6 and Figure 7 In a cross section perpendicular to the extending direction of the groove 12a, the width of the groove 12a is L3, wherein 0.4mm≤L3≤10mm, for example, 0.4mm, 0.8mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, etc.

[0128] 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 .

[0129] It can be understood that the larger the width of the groove 12a, 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 12a, that is, it is more conducive to concentrating the deformation at the groove 12a, but it will affect the structural strength of the top cover 12 at the groove 12a.

[0130] In this embodiment, by setting the width of the groove 12a to 0.4mm-10mm, the top cover 12 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 12a, which is more conducive to concentrating the deformation at the groove 12a, 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, and improving the service life of the top cover 12.

[0131] In some other embodiments, please refer to Figure 6 and Figure 7 In a cross section perpendicular to the extending direction of the groove 12a, the width of the groove 12a is L3, wherein 0.5mm≤L3≤5mm, for example, 0.5mm, 0.7mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc.

[0132] In this embodiment, by setting the width of the groove 12a to 0.5mm-5mm, the force at the connection between the shell 11 and the top cover 12 can be transferred to the groove 12a, which helps to concentrate the deformation at the groove 12a. At the same time, the top cover 12 can be further made to have sufficient strength, thereby improving the service life of the top cover 12.

[0133] In some embodiments, please refer to Figure 6 and Figure 7 , the height of the top cover 12 at the groove 12a is H3, the height of the cover body 121 is H2, and the thickness of the connection between the shell 11 and the connecting side wall 122 is L2, wherein L2≤H3<H2. In other words, the height of the top cover 12 at the groove 12a is greater than or equal to the thickness of the connection between the shell 11 and the connecting side wall 122, and is less than the height of the cover body 121.

[0134] Here, the height of the top cover 12 at the groove 12a is the height of the groove wall of the groove 12a.

[0135] It can be understood that the height of the cover body 121 is greater than the thickness of the connection between the housing 11 and the connecting side wall 122 .

[0136] Here, the depth of the groove 12 a is obtained by subtracting the height H3 of the top cover 12 at the groove 12 a from the height H2 of the cover body 121 .

[0137] In this embodiment, by setting the height of the top cover 12 at the groove 12a to L2-H2, the top cover 12 can have sufficient strength at the groove 12a and can also have sufficient deformation ability at the groove 12a.

[0138] For other embodiments, please refer to Figure 6 and Figure 7 The height of the top cover 12 at the groove 12a is H3, the height of the cover body 121 is H2, and the thickness of the connection between the shell 11 and the connecting side wall 122 is L2, wherein, That is, the height of the top cover 12 at the groove 12a is greater than or equal to 1.2 times the thickness of the connection between the housing 11 and the connecting side wall 122, and less than or equal to The height of the cover body 121 is doubled.

[0139] In this embodiment, by setting the height of the top cover 12 at the groove 12a to The top cover 12 can be further made to have sufficient strength at the groove 12a, and can also be further made to have sufficient deformation ability at the groove 12a.

[0140] In some embodiments, see Figure 4 and Figure 5The cover body 121 is surrounded by a connecting side wall 122 .

[0141] Here, the circumferential sides of the top cover 12 are connected to the outer shell 11 through the connecting side walls 122, and the top cover 12 is formed with a circle of grooves 12a, so that it is more conducive to transmitting the force at the connection between the outer shell 11 and the top cover 12 to the grooves 12a.

[0142] It should be noted that the height H1 of the connecting side wall, the height H2 of the cover body, the thickness L1 of the connecting side wall, the thickness L2 at the connection between the outer shell and the connecting side wall, the thickness L1 of the connecting side wall, the width L3 of the groove, the height H3 of the top cover at the groove 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 is not assembled.

[0143] The battery cell of the present application is further described below in conjunction with specific test examples.

[0144] The test sample of the embodiment of the present application: the top cover has a cover body, at least part of the area around the cover body is formed with a connecting side wall, the connecting side wall is connected to the shell, and the size of at least the area where the cover body is connected to the connecting side wall in the height direction of the battery cell is smaller than the size of the connecting side wall in the height direction of the battery cell. A groove is formed between the cover body and the connecting side wall.

[0145] By conducting 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 average number of cycles of the test samples of the embodiment of the present application is 13590 times, and the average number of cycles of the control group is 8900 times. When the electrode assembly cyclically expands and generates gas during charge and discharge, force will be 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 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, and increases the service life of the battery cell 10.

[0146] In one embodiment, the battery cell 10 includes a housing 11, a top cover 12 and an electrode assembly. The housing 11 has a storage 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 storage space 11a. The top cover 12 includes a cover body 121 and a connector 122, and the cover body 121 has a channel penetrating the cover body 121. The connector 122 is arranged on the side of the cover body 121 close to the electrode assembly and closes the channel.

[0147] Here, the strength of the top cover 12 at the channel can be weakened. As a result, when the electrode assembly expands cyclically and generates gas during charge and discharge, and a force is applied to the connection between the outer shell 11 and the top cover 12, the force is more easily transmitted to the top cover 12 at the channel. In other words, the area of ​​the top cover 12 at the channel is equivalent to forming 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 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.

[0148] In one embodiment, the cover body 121 can form a circle of strength weakening structure in the area where the cover body 121 is close to the connection with the outer shell 11 by setting a circle of channels extending along the edge of the cover body 121. As a result, the force at the connection between the outer shell 11 and the top cover 12 can be more easily transmitted to the area of ​​the top cover 12 located in the channel, thereby reducing the risk of fatigue cracking of the connection structure between the outer shell 11 and the top cover 12.

[0149] In other embodiments, at least one long side of the cover body 121 is provided with a channel extending along the edge of the cover body 121, that is, the cover body 121 can have a channel on one long side, or two long sides are provided with channels while the two short sides have no channels.

[0150] In this embodiment, by providing a channel corresponding to the contour of the cover body 121 on at least one long side of the cover body 121, while ensuring that the top cover 12 has sufficient structural strength, the force at the connection between the outer shell 11 and the top cover 12 can be easily transmitted to the area of ​​the top cover 12 located at the channel, thereby reducing the risk of fatigue cracking of the connection structure between the outer shell 11 and the top cover 12.

[0151] Exemplarily, the battery cell 10 includes a shell and an electrode assembly. The shell includes a top cover 12 and a shell 11 having 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. 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 a side of the cover body 121 facing the electrode assembly, and the other end extends in a direction away from the cover body 121. The shell 11 is connected to at least the outer side wall of the connecting side wall 122.

[0152] 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 at least the outer side wall of the connecting side wall 122. This structure can improve the deformation ability of the top cover 12. 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 easily transmitted to the top cover 12 to cause the top cover 12 to deform, thereby reducing the stress on the connection structure 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, improving the shell's expansion resistance, and increasing the service life of the battery cell 10. In addition, the outer shell 11 is connected to at least the outer side wall of the connecting side wall 122, which 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.

[0153] Exemplarily, at least a portion of the connection between the cover body 121 and the connecting side wall 122 is thinned to form a deformation zone, and the minimum wall thickness of the deformation zone is smaller than the wall thickness of the cover body 121 and the connecting side wall 122 .

[0154] The connection point between the cover body 121 and the connecting side wall 122 is the corner of the top cover 12 .

[0155] The minimum wall thickness of the deformation area is smaller than the wall thickness of the cover body 121 and the connecting side wall 122 , that is, it is beneficial for the force at the connection between the shell 11 and the top cover 12 to be transmitted to the deformation area of ​​the top cover 12 to deform the deformation area.

[0156] In this embodiment, by thinning the connection between the cover body 121 and the connecting side wall 122, the strength of the connection between the cover body 121 and the connecting side wall 122 can be weakened to form a deformation area, which is further conducive to the force of the connection between the shell 11 and the top cover 12 being transmitted to the deformation area of ​​the top cover 12 to deform the deformation area, thereby further reducing the risk of fatigue cracking of the connection structure between the shell 11 and the top cover 12. In addition, by controlling the deformation of the deformation area of ​​the top cover 12, the position of the deformation area of ​​the top cover 12 can be controlled, which is conducive to improving the reliability and expansion resistance of the shell.

[0157] 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.

[0158] 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 shell and a top cover, wherein the shell has a containing space and an opening, and the top cover sealing cover is arranged at the opening; An electrode assembly is disposed in the accommodation space; Among them, the top cover has a cover body, and a connecting side wall is formed in at least a partial area of ​​the circumference of the cover body, and the connecting side wall is connected to the outer shell. The size of at least the area where the cover body is connected to the connecting side wall in the height direction of the battery cell is smaller than the size of the connecting side wall in the height direction of the battery cell.

2. The battery cell according to claim 1, characterized in that: The dimension of the connecting side wall in the height direction of the battery cell is greater than the dimension of the cover body in the height direction of the battery cell.

3. The battery cell according to claim 1, characterized in that: The end surface of the connecting side wall is flush with the end surface of the shell.

4. The battery cell according to claim 1, characterized in that: The height of the connecting side wall is H1, and the height of the cover body is H2, wherein H2≤H1≤4H2.

5. The battery cell according to claim 1, characterized in that: The height of the connecting side wall is H1, and the height of the cover body is H2, wherein H2≤H1≤3H2.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The thickness of the connecting side wall is L1, and the thickness of the connection portion between the outer shell and the connecting side wall is L2, wherein L2≤L1≤6L2.

7. The battery cell according to any one of claims 1 to 5, characterized in that: The thickness of the connecting side wall is L1, and the thickness of the connection portion between the outer shell and the connecting side wall is L2, wherein 1.2L2≤L1≤3L2.

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

9. The battery cell according to claim 8, characterized in that: In a cross section perpendicular to the extending direction of the groove, the width of the groove is L3, wherein 0.4 mm≤L3≤10 mm.

10. The battery cell according to claim 8, characterized in that: In a cross section perpendicular to the extending direction of the groove, the width of the groove is L3, wherein 0.5 mm≤L3≤5 mm.

11. The battery cell according to claim 8, characterized in that: The height of the top cover at the groove is H3, the height of the cover body is H2, and the thickness of the connection between the shell and the connecting side wall is L2, wherein L2≤H3<H2.

12. The battery cell according to claim 8, characterized in that: The height of the top cover at the groove is H3, the height of the cover body is H2, and the thickness of the connection between the shell and the connecting side wall is L2, wherein, 13. The battery cell according to any one of claims 1 to 5, characterized in that: The height of the cover body is H2, wherein 1mm≤H2≤5mm; and / or the thickness of the connection between the shell and the connecting side wall is L2, wherein 0.4mm≤L2≤2mm.

14. The battery cell according to any one of claims 1 to 5, characterized in that: The height of the cover body is H2, wherein 1.5 mm ≤ H2 ≤ 3 mm; and / or the thickness of the connection between the shell and the connecting side wall is L2, wherein 0.6 mm ≤ L2 ≤ 1.7 mm.

15. The battery cell according to any one of claims 1 to 5, characterized in that: The circumference of the cover body is surrounded by a circle of the connecting side wall.

16. A battery, characterized in that: Comprising at least one battery cell according to any one of claims 1 to 15.

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

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