Battery cell, battery and electrical device

Abstract

A battery cell (100), a battery (200), and an electrical device. The battery cell (100) comprises a housing (10), an electrode assembly (30) and an end cover (20). The housing (10) is provided with a first end part (11) and a second end part (12) opposite to the first end part (11). The first end part (11) is provided with an opening (111). The housing (10) comprises an inner wall surface (13) and an outer wall surface (14). The outer wall surface (14) is provided with a weak structure (141). The weak structure (141) is closer to the opening (111) relative to the second end part (12). The housing (10) comprises a first wall (15) and a second wall (16) connected to the first wall (15). The area of the first wall (15) is greater than the area of the second wall (16). The weak structure (141) is formed on the outer wall surface (14) of the first wall (15). The electrode assembly (30) is arranged in the housing (10). The end cover (20) is in sealed connection with the housing (10) and seals the opening (111).

Description

Battery cells, batteries and electrical equipment

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 202420584524.9 filed with the State Intellectual Property Office of China on March 25, 2024, and the entire text of which is incorporated herein by reference. Technical Field

[0003] 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

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become a crucial component of the industry's sustainable development. Battery technology, in turn, is a crucial factor in the development of electric vehicles.

[0005] During the charge and discharge process of the battery cell, the electrode assembly of the battery cell will continue to expand and contract. After long-term use, the connection between the battery cell shell and the end cover is prone to cracking, reducing the stability of the battery cell.

[0006] Summary of the Invention

[0007] The present application provides a battery cell, a battery, and an electrical device, which can improve the stability of the battery cell while reducing the impact on the insulation performance of the battery cell.

[0008] The battery cell of the embodiment of the present application includes a shell, an electrode assembly and an end cover, the shell has a first end and a second end opposite to the first end, the first end is formed with an opening, the shell includes an inner wall surface and an outer wall surface, the outer wall surface is provided with a weak structure, the weak structure is closer to the opening than the second end, the shell includes a first wall and a second wall connected to the first wall, the area of ​​the first wall is greater than the area of ​​the second wall, the outer wall surface of the first wall is formed with a weak structure, the electrode assembly is arranged in the shell, and the end cover is sealed and connected to the shell and closes the opening.

[0009] During the charge and discharge process of the battery cell according to the embodiments of the present application, the electrode assembly continuously expands and contracts. The weakened structure can preferentially deform when the electrode assembly expands, reducing the degree of deformation caused by the electrode assembly expansion at the connection between the outer casing and the end cap, reducing the risk of cracking at the connection between the outer casing and the end cap, and thus improving the service life of the outer casing, thereby improving the stability of the battery cell. In addition, because the area of ​​the first wall is larger than that of the second wall, the first wall is more susceptible to deformation under the action of the electrode assembly. Therefore, by providing a weakened structure on the outer surface of the first wall, the weakened structure can better absorb the deformation of the outer casing, reducing the deformation caused by the electrode assembly expansion at the connection between the first wall and the end cap, reducing the risk of cracking at the connection between the first wall and the end cap, and thus improving the service life of the outer casing.

[0010] In certain embodiments, a weakened structure is formed on an outer wall surface of the second wall.

[0011] In this way, by setting a weak structure on the outer wall surface of the second wall, the weak structure can preferentially absorb the impact on the outer wall surface of the second wall when the electrode assembly expands, reduce the deformation of the connection between the second wall and the end cover caused by the expansion of the electrode assembly, and reduce the risk of cracking at the connection between the second wall and the end cover, thereby improving the service life of the shell.

[0012] In certain embodiments, the weakened structure comprises a groove formed on the outer wall surface of the housing, and the groove located on the outer wall surface of the first wall is connected to the groove located on the outer wall surface of the second wall.

[0013] In this way, the groove can reduce the thickness of the shell, making it easier to form a weak structure. The groove located on the outer wall surface of the first wall is connected to the groove located on the outer wall surface of the second wall, so that the deformation consistency of the weak structure at the same position of the shell is better, which is beneficial to improving the ability of the weak structure to absorb impact on the shell.

[0014] In some embodiments, the shell includes a first part and a second part connected to the first part, the first part forms a first end, the second part forms a second end away from the end of the first part, the ratio of the height of the first part to the second part along the direction from the first end to the second end is greater than or equal to 3:7, and the weak structure is located on the second part.

[0015] In this way, the weak structure is located on the second part, so that the weak structure is far away from the end cover, and the deformation of the shell when the electrode assembly expands can be concentrated on the second part, reducing the impact on the first part and reducing the risk of cracking at the connection between the shell of the first part and the end cover, thereby improving the service life of the shell.

[0016] In certain embodiments, the weak structure has a groove formed on the outer wall surface, and a ratio of a thickness of the second portion at the groove to a maximum thickness of the second portion is greater than or equal to 0.4.

[0017] In this way, the weak structure can be easily deformed to absorb the impact on the shell, and has appropriate strength and is not easy to break.

[0018] In certain embodiments, the weakening structure has a groove formed in the outer wall surface.

[0019] In this way, the groove can reduce the thickness of the shell, making it easier to form a weak structure.

[0020] In some embodiments, a height of the groove along a direction from the first end to the second end is h, and 0.2 mm ≤ h ≤ 7 mm.

[0021] In this way, when the height of the groove along the direction from the first end to the second end is within the above range, it can facilitate the formation of the groove, thereby making it easier to form a weak structure, reducing the difficulty of manufacturing the shell, and at the same time, helping to improve the ability of the weak structure to absorb impact on the shell.

[0022] In certain embodiments, 0.5 mm ≤ h ≤ 4 mm.

[0023] In this way, when the height of the groove along the direction from the first end to the second end is within the above range, it can facilitate the formation of the groove, thereby making it easier to form a weak structure, reducing the difficulty of manufacturing the shell, and at the same time, helping to improve the ability of the weak structure to absorb impact on the shell.

[0024] In some embodiments, the distance between the groove and the opening is H, t-0.5 mm ≤ H ≤ 8t, where t is the thickness of the end cap in mm.

[0025] In this way, when the distance between the groove and the opening is within the above range, the deformation of the shell during expansion of the electrode assembly can be concentrated on the weak structure, reducing the impact on the opening area and reducing the risk of cracking at the connection between the shell and the end cover, thereby improving the service life of the shell.

[0026] In certain embodiments, t≤H≤5t.

[0027] In this way, when the distance between the groove and the opening is within the above range, the deformation of the shell during expansion of the electrode assembly can be concentrated on the weak structure, reducing the impact on the opening area and reducing the risk of cracking at the connection between the shell and the end cover, thereby improving the service life of the shell.

[0028] In certain embodiments, the angle formed between the bottom surface of the groove and the side surface of the groove is an obtuse angle.

[0029] In this way, the angle formed by the bottom surface of the groove and the side surface of the groove is an obtuse angle, which can facilitate the formation of the groove, reduce the manufacturing difficulty of the shell, and thus improve the processing accuracy of the shell and the service life of the mold.

[0030] In certain embodiments, the angle formed by the bottom surface of the groove and the side surface of the groove is 95° to 175°.

[0031] In this way, when the angle formed by the bottom surface of the groove and the side surface of the groove is within the above range, the formation of the groove can be facilitated, the manufacturing difficulty of the shell can be reduced, and the processing accuracy of the shell and the service life of the mold can be improved.

[0032] In certain embodiments, the angle formed by the bottom surface of the groove and the side surface of the groove is 110° to 160°.

[0033] In this way, when the angle formed by the bottom surface of the groove and the side surface of the groove is within the above range, the formation of the groove can be facilitated, the manufacturing difficulty of the shell can be reduced, and the processing accuracy of the shell and the service life of the mold can be improved.

[0034] The battery according to the embodiment of the present application includes a battery cell.

[0035] The electrical device of the embodiment of the present application includes a battery cell or a battery, and the battery cell or the battery is used to provide electrical energy to the electrical device.

[0036] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0038] FIG1 is a schematic structural diagram of a vehicle according to some embodiments of the present application;

[0039] FIG2 is a schematic structural diagram of a battery according to some embodiments of the present application;

[0040] FIG3 is a schematic structural diagram of a battery cell according to some embodiments of the present application;

[0041] FIG4 is a schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application;

[0042] FIG5 is a front view of a battery cell according to some embodiments of the present application;

[0043] FIG6 is a top view of a battery cell according to some embodiments of the present application;

[0044] FIG7 is a left side view of a battery cell according to some embodiments of the present application;

[0045] FIG8 is a cross-sectional view taken along the AA direction in FIG5;

[0046] FIG9 is an enlarged schematic diagram of part I of FIG8;

[0047] FIG10 is an enlarged schematic diagram of part II of FIG8 .

[0048] Explanation of the accompanying drawings: 100, battery cell; 10, outer shell; 11, first end; 111, opening; 12, second end; 13, inner wall; 14, outer wall; 141, weak structure; 142, groove; 143, bottom; 144, side; 15, first wall; 16, second wall; 17, first part; 18, second part; 20, end cover; 30, electrode assembly; 200, battery; 210, casing; 300, controller; 400, motor; 1000, vehicle. DETAILED DESCRIPTION

[0049] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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 the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0051] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0052] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, 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 this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0054] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0055] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0056] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0057] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0058] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0059] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0060] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The current collector uncoated with the positive active material layer protrudes from the current collector coated with the positive active material layer, and the current collector uncoated with the positive active material layer serves as the positive electrode tab. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The current collector uncoated with the negative active material layer protrudes from the current collector coated with the negative active material layer, and the current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon or silicon, among others. To ensure that high currents can pass without melting, the positive electrode tabs are multiple and stacked together, and the negative electrode tabs are multiple and stacked together. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene).

[0061] A battery cell also includes a housing and end caps. The housing protects the electrode assembly from the outside, preventing foreign matter from affecting the charge or discharge of the electrode assembly. The end caps and the housing together define a housing for the electrode assembly, electrolyte, and other components.

[0062] In the prior art, during the charge and discharge process of the battery cell, the electrode assembly of the battery cell will continuously expand and contract. After long-term use, the connection between the battery cell shell and the end cover is prone to cracking, thereby reducing the service life of the shell and the stability of the battery cell.

[0063] In order to improve the stability of the battery cell, the present application provides a shell for the battery cell, and the outer wall of the shell is provided with a weak structure. The deformation of the shell when the electrode assembly expands is concentrated at the weak structure, thereby reducing the deformation at the connection between the shell and the end cover, reducing the risk of cracking at the connection between the shell and the end cover, and improving the service life of the shell, thereby improving the stability of the battery cell.

[0064] The battery cells disclosed in the embodiments of the present application can be used, but are not limited to, in electrical equipment such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical equipment.

[0065] The embodiments of the present application provide an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. 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, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0066] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0067] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 200 is provided inside the vehicle 1000, and the battery 200 can be provided at the bottom, head or tail of the vehicle 1000. The battery 200 can be used to power the vehicle 1000. For example, the battery 200 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 300 and a motor 400. The controller 300 is used to control the battery 200 to power the motor 400, for example, for starting, navigating and driving the vehicle 1000.

[0068] In some embodiments of the present application, the battery 200 can serve not only 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.

[0069] In some embodiments, the battery 200 may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0070] Please refer to Figure 2, which is a schematic diagram of the exploded structure of a battery 200 provided in some embodiments of the present application. The battery 200 includes a housing 210 and a battery cell 100, with the battery cell 100 being housed within the housing 210. The housing 210 is used to provide a storage space for the battery cell 100 and can adopt a variety of structures.

[0071] In the battery 200, there may be multiple battery cells 100, and the multiple battery cells 100 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 100. The multiple battery cells 100 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 100 may be housed within the housing 210. Of course, the battery 200 may also be a battery module formed by first connecting multiple battery cells 100 in series, in parallel, or in a hybrid connection, and then the multiple battery modules are further connected in series, in parallel, or in a hybrid connection to form an entire battery cell, which is then housed within the housing 210. The battery 200 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 100.

[0072] Each battery cell 100 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 100 may be cylindrical, flat, rectangular, or in other shapes.

[0073] According to some embodiments of the present application, please refer to Figures 3-5. Figure 3 is a schematic structural diagram of a battery cell 100 according to some embodiments of the present application; Figure 4 is a schematic exploded structural diagram of a battery cell 100 according to some embodiments of the present application; and Figure 5 is a front view of a battery cell 100 according to some embodiments of the present application. The battery cell 100 according to the embodiment of the present application includes a housing 10, an electrode assembly 3030, and an end cap 20. The housing 10 has a first end 11 and a second end 12 opposite to the first end 11. The first end 11 is formed with an opening 111. The housing 10 includes an inner wall 13 and an outer wall 14. The outer wall 14 is provided with a weakening structure 141. The weakening structure 141 is closer to the opening 111 than the second end 12. The electrode assembly 30 is disposed in the housing 10. The end cap 20 is sealed to the housing 10 and closes the opening 111.

[0074] Specifically, the outer shell 10 is a hollow structure, and a holding cavity for accommodating the electrode assembly 30 and the electrolyte is formed therein. The outer shell 10 can be in various shapes, such as a cylinder, a rectangular parallelepiped, etc. The shape of the outer shell 10 can be determined according to the specific shape of the electrode assembly 30. For example, if the electrode assembly 30 is a cylindrical structure, a cylindrical outer shell 10 can be selected, and the shape of the opening 111 can be circular; if the electrode assembly 30 is a rectangular parallelepiped structure, a rectangular outer shell 10 can be selected, and the shape of the opening 111 can be square. The material of the outer shell 10 can be various, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc.

[0075] The first end portion 11 may be located at the top of the housing 10 , the second end portion 12 may be located at the bottom of the housing 10 , and the electrode assembly 30 may enter the interior of the housing 10 through the opening 111 of the first end portion 11 .

[0076] The inner wall surface 13 may be the surface of the housing 10 that contacts the internal environment, while the outer wall surface 14 may be the surface of the housing 10 that contacts the external environment. The outer wall surface 14 is provided with a weakening structure 141, which is used to withstand deformation at the connection between the housing 10 and the end cap 20 when the electrode assembly 30 expands. The weakening structure 141 can be formed by thinning the material, such as by scoring or slotting the outer wall surface 14. On the outer wall surface 14, the thickness of the area surrounding the weakening structure 141 is greater than the thickness at the weakening structure 141.

[0077] The electrode assembly 30 is the core component that enables the charge and discharge functions of the battery cell 100. It includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive and negative electrode sheets have opposite polarities, and the separator is used to insulate the positive and negative electrode sheets. The electrode assembly 30 primarily operates by the movement of metal ions between the positive and negative electrode sheets.

[0078] The end cap 20 is a component that seals the opening 111 of the outer shell 10 to isolate the internal environment of the battery cell 100 from the external environment. The end cap 20 and the outer shell 10 together define a storage space for accommodating the electrode assembly 30, the electrolyte, and other components. The shape of the end cap 20 can be adapted to the shape of the outer shell 10. For example, if the outer shell 10 is a rectangular parallelepiped structure, the end cap 20 is a rectangular plate structure adapted to the outer shell 10. For another example, if the outer shell 10 is a cylindrical structure, the end cap 20 is a circular plate structure adapted to the outer shell 10. The material of the end cap 20 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cap 20 and the outer shell 10 can be the same or different. The number of end caps 20 can be one, and the end cap 20 and the outer shell 10 can be connected by welding.

[0079] During the charge and discharge process of the battery cell 100 in the embodiment of the present application, the electrode assembly 30 will continuously expand and contract. The weak structure 141 can be deformed preferentially when the electrode assembly 30 expands, thereby reducing the degree of deformation caused by the expansion of the electrode assembly 30 on the connection between the outer shell 10 and the end cover 20, reducing the risk of cracking at the connection between the outer shell 10 and the end cover 20, and increasing the service life of the outer shell 10, thereby improving the stability of the battery cell 100.

[0080] Referring to Figures 4, 6, and 7, Figure 6 is a top view of a battery cell 100 according to some embodiments of the present application, and Figure 7 is a left side view of a battery cell 100 according to some embodiments of the present application. In certain embodiments, the housing 10 includes a first wall 15 and a second wall 16 connected to the first wall 15. The area of ​​the first wall 15 is larger than that of the second wall 16. The outer wall surface 14 of the first wall 15 is formed with a weakening structure 141.

[0081] Specifically, the first wall 15 and the second wall 16 may be side walls of the housing 10. When the housing 10 is a rectangular parallelepiped structure, the first wall 15 may be perpendicular to the second wall 16, and the first wall 15 and the second wall 16 may be perpendicular to the second end 12. The first wall 15 and the second wall 16 may be rectangular plate-like structures. There may be two first walls 15 and two second walls 16, with the two first walls 15 and the two second walls 16 being oppositely disposed. When the first wall 15 and the second wall 16 have the same length, the width of the first wall 15 may be greater than the width of the second wall 16.

[0082] The weak structure 141 can be formed by removing some material from the outer wall surface 14 of the first wall 15 toward the inner wall surface 13 of the first wall 15, for example, by scoring or slotting the outer wall surface 14 of the first wall 15. On the outer wall surface 14 of the first wall 15, the thickness of the area surrounding the weak structure 141 is greater than the thickness at the weak structure 141.

[0083] In this way, since the area of ​​the first wall 15 is larger than that of the second wall 16, the first wall 15 is more easily deformed under the action of the electrode assembly 30. Therefore, by setting a weak structure 141 on the outer wall surface 14 of the first wall 15, the weak structure 141 can better absorb the deformation caused by the outer shell 10, reduce the deformation of the connection between the first wall 15 and the end cover 20 caused by the expansion of the electrode assembly 30, and reduce the risk of cracking at the connection between the first wall 15 and the end cover 20, thereby improving the service life of the outer shell 10.

[0084] 4 and 7 , in some embodiments, a weak structure 141 is formed on the outer wall surface 14 of the second wall 16 .

[0085] Specifically, the weak structure 141 can be formed by removing a portion of material from the outer wall surface 14 of the second wall 16 toward the inner wall surface 13 of the second wall 16, for example, by scoring or grooving the outer wall surface 14 of the second wall 16. On the outer wall surface 14 of the second wall 16, the thickness of the area surrounding the weak structure 141 is greater than the thickness at the weak structure 141.

[0086] In this way, by setting a weak structure 141 on the outer wall surface 14 of the second wall 16, the weak structure 141 can preferentially absorb the impact of the outer wall surface 14 of the second wall 16 when the electrode assembly 30 expands, reduce the deformation of the connection between the second wall 16 and the end cover 20 caused by the expansion of the electrode assembly 30, and reduce the risk of cracking at the connection between the second wall 16 and the end cover 20, thereby improving the service life of the outer shell 10.

[0087] Referring to Figures 8-10, Figure 8 is a cross-sectional view taken along line AA of Figure 5; Figure 9 is an enlarged schematic view of portion I of Figure 8; and Figure 10 is an enlarged schematic view of portion II of Figure 8. In certain embodiments, the weakening structure 141 comprises a groove 142 formed in the outer wall 14 of the housing 10, with the groove 142 on the outer wall 14 of the first wall 15 and the groove 142 on the outer wall 14 of the second wall 16 interconnected.

[0088] Specifically, the groove 142 can be formed by removing some material from the outer wall 14. The cross-sectional shape of the groove 142 can be arcuate, square, trapezoidal, etc. The groove 142 can extend from the outer wall 14 along the thickness direction of the housing 10 toward the inner wall 13. The groove 142 can be arranged circumferentially along the outer wall 14 of the housing 10. The provision of the groove 142 reduces the thickness of the housing 10 in the area where the weak structure 141 is provided.

[0089] In this way, the groove 142 can reduce the thickness of the shell 10, so that the weak structure 141 can be formed more easily. The groove 142 located on the outer wall surface 14 of the first wall 15 is connected to the groove 142 located on the outer wall surface 14 of the second wall 16, so that the deformation consistency of the weak structure 141 at the same position of the shell 10 is better, which is beneficial to improving the ability of the weak structure 141 to absorb the impact of the shell 10.

[0090] Please refer to Figure 4. In some embodiments, the housing 10 includes a first portion 17 and a second portion 18 connected to the first portion 17. The first portion 17 forms a first end 11, and the end of the second portion 18 away from the first portion 17 forms a second end 12. The ratio of the height of the first portion 17 to the second portion 18 along the direction from the first end 11 to the second end 12 is greater than or equal to 3:7, and the weak structure 141 is located on the second portion 18.

[0091] Specifically, the first portion 17 may be the portion connecting the housing 10 and the end cap 20. The thickness of the first portion 17 gradually decreases along the direction from the first end 11 to the second end 12. The second portion 18 may be a structure of equal thickness. The first portion 17 and the second portion 18 may be integrally formed. The ratio of the height of the first portion 17 to the second portion 18 along the direction from the first end 11 to the second end 12 may be 3:7, 2:3, 1:1, etc. For example, when the height of the housing 10 along the direction from the first end 11 to the second end 12 is 100 mm, the height of the first portion 17 may be 30 mm and the height of the second portion 18 may be 70 mm. Alternatively, the height of the first portion 17 may be 40 mm and the height of the second portion 18 may be 60 mm. Alternatively, the height of the first portion 17 may be 50 mm and the height of the second portion 18 may be 50 mm.

[0092] In this way, the weak structure 141 is located on the second part 18, so that the weak structure 141 is far away from the end cover 20, so that the deformation of the outer shell 10 when the electrode assembly 30 expands can be concentrated on the second part 18, reducing the impact on the first part 17, and reducing the risk of cracking at the connection between the outer shell 10 and the end cover 20 of the first part 17, thereby improving the service life of the outer shell 10.

[0093] 9 and 10 , in some embodiments, the weak structure 141 has a groove 142 formed on the outer wall 14 , and the ratio of the thickness of the second portion 18 at the groove 142 to the maximum thickness of the second portion 18 is greater than or equal to 0.4.

[0094] Specifically, the thickness of the second portion 18 at the groove 142 can be the distance between the bottom surface 143 of the groove 142 and the inner wall surface 13. The maximum thickness of the second portion 18 can be the distance between the outer wall surface 14 and the inner wall surface 13. The ratio of the thickness of the second portion 18 at the groove 142 to the maximum thickness of the second portion 18 can be any one of 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, or a range of values ​​therebetween. When the ratio of the thickness of the second portion 18 at the groove 142 to the maximum thickness of the second portion 18 is less than 0.4, the strength of the weak structure 141 is low and the weak structure 141 is easily broken.

[0095] In this way, the weak structure 141 is easily deformed to absorb the impact on the housing 10 and has appropriate strength and is not easy to break.

[0096] 9 and 10 , in some embodiments, the weak structure 141 has a groove 142 formed on the outer wall surface 14 .

[0097] Specifically, the groove 142 can be formed by removing some material from the outer wall surface 14. The cross-sectional shape of the groove 142 can be arcuate, square, trapezoidal, etc. The groove 142 can extend from the outer wall surface 14 toward the inner wall surface 13 along the thickness direction of the housing 10. The groove 142 can be provided on the outer wall surface 14 of the first wall 15, or on the outer wall surface 14 of the second wall 16, or can be provided along the circumference of the outer wall surface 14 of the housing 10. The provision of the groove 142 reduces the thickness of the region of the housing 10 where the weak structure 141 is provided.

[0098] In this way, the groove 142 can reduce the thickness of the housing 10 , thereby making it easier to form the weak structure 141 .

[0099] 4 , 9 and 10 , in some embodiments, the height of the groove 142 along the direction from the first end 11 to the second end 12 is h, and 0.2 mm ≤ h ≤ 7 mm.

[0100] Specifically, the height of the groove 142 along the direction from the first end 11 to the second end 12 can be the distance between the two connection points of the groove 142 and the outer wall surface 14, and h can be any one of 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm or a range value between any two of them.

[0101] When the height of the groove 142 along the direction from the first end 11 to the second end 12 is less than 0.2 mm, the processing difficulty of the groove 142 is relatively large, thereby increasing the manufacturing difficulty of the shell 10; when the height of the groove 142 along the direction from the first end 11 to the second end 12 is greater than 7 mm, the effect of the weak structure 141 in withstanding deformation is not significantly improved.

[0102] In this way, when the height of the groove 142 along the direction from the first end 11 to the second end 12 is within the above range, it can facilitate the formation of the groove 142, thereby making it easier to form the weak structure 141, reducing the manufacturing difficulty of the shell 10, and at the same time, helping to improve the ability of the weak structure 141 to absorb the impact of the shell 10.

[0103] Referring to FIG. 9 , in some embodiments, 0.5 mm ≤ h ≤ 4 mm.

[0104] Specifically, h can be any point value of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, and 4 mm, or a range value between any two of them.

[0105] In this way, when the height of the groove 142 along the direction from the first end 11 to the second end 12 is within the above range, it can facilitate the formation of the groove 142, thereby making it easier to form the weak structure 141, reducing the manufacturing difficulty of the shell 10, and at the same time, helping to improve the ability of the weak structure 141 to absorb the impact of the shell 10.

[0106] 4 , 9 and 10 , in some embodiments, the distance between the groove 142 and the opening 111 is H, t-0.5mm≤H≤8t, where t is the thickness of the end cap 20 in mm.

[0107] Specifically, the distance between the groove 142 and the opening 111 can be the distance between the connection point between the groove 142 and the outer wall surface 14 close to the first end 11 and the opening 111. When the thickness of the end cover 20 is 1.5 mm, the distance H between the groove 142 and the opening 111 is 1 mm to 12 mm, that is, the distance H between the groove 142 and the opening 111 can be any one of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, and 12 mm, or a range value between any two of them.

[0108] When the distance H between the groove 142 and the opening 111 is less than t-0.5 mm, the groove 142 is close to the opening 111, so that the deformation of the outer shell 10 when the electrode assembly 30 expands will affect the opening 111 area, thereby increasing the risk of cracking at the connection between the outer shell 10 and the end cover 20; when the distance H between the groove 142 and the opening 111 is greater than 8t, the groove 142 is far away from the opening 111, reducing the concentration of deformation of the outer shell 10 at the weak structure 141, thereby increasing the risk of cracking at the connection between the outer shell 10 and the end cover 20.

[0109] In this way, when the distance between the groove 142 and the opening 111 is within the above range, the deformation of the shell 10 when the electrode assembly 30 expands can be concentrated on the weak structure 141, reducing the impact on the opening 111 area and reducing the risk of cracking at the connection between the shell 10 and the end cover 20, thereby improving the service life of the shell 10.

[0110] Referring to FIG. 9 , in some embodiments, t≤H≤5t.

[0111] Specifically, when the thickness of the end cover 20 is 1.5 mm, the distance H between the groove 142 and the opening 111 is 1.5 mm to 7.5 mm, that is, the distance H between the groove 142 and the opening 111 can be any point value of 1.5 mm, 2.5 mm, 3.5 mm, 4.5 mm, 5.5 mm, 6.5 mm, 7.5 mm or a range value between any two of them.

[0112] In this way, when the distance between the groove 142 and the opening 111 is within the above range, the deformation of the shell 10 when the electrode assembly 30 expands can be concentrated on the weak structure 141, reducing the impact on the opening 111 area and reducing the risk of cracking at the connection between the shell 10 and the end cover 20, thereby improving the service life of the shell 10.

[0113] 10 , in some embodiments, an angle θ formed between the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 is an obtuse angle.

[0114] Specifically, the groove 142 may be formed by a bottom surface 143 and two side surfaces 144. The bottom surface 143 of the groove 142 may be parallel to the outer wall surface 14, and the side surfaces 144 of the groove 142 may connect the bottom surface 143 of the groove 142 and the outer wall surface 14 of the housing 10. When the cross-sectional shape of the groove 142 is square, the angle θ formed by the bottom surface 143 of the groove 142 and the side surfaces 144 of the groove 142 may be 90°; when the cross-sectional shape of the groove 142 is trapezoidal, the angle θ formed by the bottom surface 143 of the groove 142 and the side surfaces 144 of the groove 142 may be greater than 90°.

[0115] Thus, the angle θ formed by the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 is an obtuse angle, which can facilitate the formation of the groove 142 and reduce the manufacturing difficulty of the shell 10, thereby improving the processing accuracy of the shell 10 and the service life of the mold.

[0116] 10 , in some embodiments, an angle θ formed between the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 is in a range of 95° to 175°.

[0117] Specifically, the angle θ formed by the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 can be any point value of 95°, 105°, 115°, 125°, 135°, 145°, 155°, 165°, 175° or a range value between any two of them.

[0118] Thus, when the angle θ formed by the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 is within the above range, the formation of the groove 142 can be facilitated, the manufacturing difficulty of the shell 10 can be reduced, and the processing accuracy of the shell 10 and the service life of the mold can be improved.

[0119] 10 , in some embodiments, an angle θ formed between the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 is in a range of 110° to 160°.

[0120] Specifically, the angle θ formed by the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 can be any point value of 110°, 120°, 130°, 140°, 150°, 160°, or a range value between any two of them.

[0121] Thus, when the angle θ formed by the bottom surface 143 of the groove 142 and the side surface 144 of the groove 142 is within the above range, the formation of the groove 142 can be facilitated, the manufacturing difficulty of the shell 10 can be reduced, and the processing accuracy of the shell 10 and the service life of the mold can be improved.

[0122] Please refer to Figure 4. The battery cell 100 of the embodiment of the present application includes a shell 10, an electrode assembly 30 and an end cover 20. The shell 10 has a first end 11 and a second end 12 opposite to the first end 11. The first end 11 is formed with an opening 111. The shell 10 is provided with a weak structure 141. The weak structure 141 is closer to the opening 111 than the second end 12. The electrode assembly 30 is arranged in the shell 10, and the end cover 20 is sealed and connected to the shell 10 and closes the opening 111.

[0123] In this way, during the charge and discharge process of the battery cell 100, the electrode assembly 30 will continuously expand and contract, and the weak structure 141 can be deformed preferentially when the electrode assembly 30 expands, thereby reducing the degree of deformation caused by the expansion of the electrode assembly 30 on the connection between the outer shell 10 and the end cover 20, reducing the risk of cracking at the connection between the outer shell 10 and the end cover 20, and improving the service life of the outer shell 10, thereby improving the stability of the battery cell 100.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, wherein: include: a housing having a first end and a second end opposite the first end, the first end forming an opening, the housing including an inner wall surface and an outer wall surface, the outer wall surface being provided with a weakening structure, the weakening structure being closer to the opening than the second end, the housing including a first wall and a second wall connected to the first wall, the area of ​​the first wall being larger than the area of ​​the second wall, and the outer wall surface of the first wall being provided with the weakening structure; an electrode assembly disposed in the housing; and, An end cover is sealed to the housing and closes the opening.

2. The battery cell according to claim 1, wherein: The weak structure is formed on the outer wall surface of the second wall.

3. The battery cell according to claim 2, wherein: The weak structure has a groove formed on the outer wall surface of the shell, and the groove located on the outer wall surface of the first wall is connected to the groove located on the outer wall surface of the second wall.

4. The battery cell according to any one of claims 1 to 3, wherein: The shell includes a first part and a second part connected to the first part, the first part forms the first end, the end of the second part away from the first part forms the second end, the ratio of the height of the first part to the second part along the direction from the first end to the second end is greater than or equal to 3:7, and the weak structure is located on the second part.

5. The battery cell according to claim 4, wherein: The weak structure has a groove formed on the outer wall surface, and a ratio of a thickness of the second portion at the groove to a maximum thickness of the second portion is greater than or equal to 0.

4. The battery cell according to claim 1 , wherein: The weak structure has a groove formed on the outer wall surface.

7. The battery cell according to claim 6, wherein: A height of the groove along a direction from the first end portion to the second end portion is h, and 0.2 mm ≤ h ≤ 7 mm.

8. The battery cell according to claim 7, wherein: 0.5mm≤h≤4mm.

9. The battery cell according to any one of claims 3, 6 to 8, wherein: The distance between the groove and the opening is H, t-0.5mm≤H≤8t, wherein t is the thickness of the end cover in mm.

10. The battery cell according to claim 9, wherein: t≤H≤5t.

11. The battery cell according to any one of claims 3, 6 to 10, wherein: An angle formed by the bottom surface of the groove and the side surface of the groove is an obtuse angle.

12. The battery cell according to claim 11, wherein: The angle formed by the bottom surface of the groove and the side surface of the groove is 95° to 175°.

13. The battery cell according to claim 12, wherein: The angle formed by the bottom surface of the groove and the side surface of the groove is 110° to 160°.

14. A battery, wherein: The invention comprises the battery cell according to any one of claims 1 to 13.

15. An electrical device, wherein: The invention comprises the battery cell according to any one of claims 1 to 13 or the battery according to claim 14.

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