Battery cells, batteries, energy storage devices, and electrical devices

Abstract

The invention comprises a battery cell (10), a battery (100), an energy storage device (2000), and an electrical device. The battery cell (10) includes a case (11). The case (11) has an opening (11a) formed at an end along a first direction. In the circumferential direction of the opening (11a), the case (11) includes a first wall (110), a corner region (112), and a second wall (113) connected in order. The first wall (110) comprises a first main body (1100) and a first thickened portion (1101) arranged in a first direction, the first main body (1100) being further away from the opening (11a) than the first thickened portion (1101), and the first thickened portion (1101) having a maximum thickness greater than the thickness of the first main body (1100). The corner region (112) comprises a second main body (1120) and a second thickening portion (1121) arranged in a first direction, wherein the second main body (1120) is further away from the opening (11a) than the second thickening portion (1121), and the second thickening portion (1121) has a maximum thickness greater than the thickness of the second main body (1120). The provided technical means can improve the reliability of the battery cell (10).

Description

Technical Field

[0005]

[0001] (Cross - reference to related applications) This application claims the priority of PCT patent application PCT / CN2023 / 134129, titled "Case, Battery Cell, Battery and Electrical Device", filed on November 24, 2023, and the priority of Chinese patent application 202323280449.1, titled "Battery Cell, Battery, Energy Storage Device and Electrical Device", filed on November 30, 2023. All the contents of the above applications are incorporated herein by reference.

[0002] This application relates to the technical field of batteries, specifically to battery cells, batteries, energy storage devices and electrical devices.

Background Art

[0003] Energy conservation and emission reduction are the key to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their energy - saving and environmental protection advantages.Mobile for battery technology is an important factor related to its development.

[0004] In the development of battery technology, how to improve the reliability of batteries is a technical problem that needs to be solved urgently in battery technology.

Summary of the Invention

Problems to be Solved by the Invention

[0008] In the above solution, by providing a first reinforced section on the first wall, a heat-affected zone with low strength is formed in the case due to welding, which improves the problem of the first wall cracking due to insufficient strength when subjected to impact, thereby providing high reliability to the battery. At the same time, by providing a second reinforced section in the corner region, the strength of the part corresponding to the opening in the corner region is increased, which improves the problem of the corner region cracking due to stress concentration in the case manufacturing process caused by the installation of the first reinforced section (for example, in tensile forming of the case, the stress generated during demolding is concentrated in the part corresponding to the opening in the corner region), thereby providing high reliability to the battery cell.

[0009] According to some embodiments of this application, the maximum thickness of the second reinforced portion is greater than the maximum thickness of the first reinforced portion.

[0010] In the above solution, by making the maximum thickness of the second reinforced section greater than the maximum thickness of the first reinforced section, the strength of the part corresponding to the opening in the corner region can be effectively increased. This effectively increases the overall thickness of the case, reduces the risk of the case cracking due to impact, and effectively improves the problem of corner region cracking due to stress concentration in the case manufacturing process, thereby providing high reliability to the battery cell.

[0011] According to some embodiments of the present application, when the maximum thickness of the second thickening portion is T1, the thickness of the second main body portion is T2, the maximum thickness of the first thickening portion is t1, and the thickness of the first main body portion is t2, E≥F is satisfied, where E=(T1 - T2) / T2 and F=(t1 - t2) / t2.

[0012] In the above solution, by limiting the degree E by which the second thickening portion is thicker than the second main body portion to be not less than the degree F by which the first thickening portion is thicker than the first main body portion, the problem that the corner region cracks due to stress concentration in the case manufacturing process caused by the installation of the first thickening portion can be effectively improved, and high reliability can be given to the battery cell.

[0013] According to some embodiments of the present application, when the maximum thickness of the second thickening portion is T1 and the thickness of the second main body portion is T2, 0 < E < 30% is satisfied, where E=(T1 - T2) / T_{2}.

[0014] In the above solution, by limiting the degree E by which the second thickening portion is thicker than the second main body portion, the strength of the corner region can be improved, the risk that the corner region cracks due to stress concentration can be reduced, and at the same time, the risk that the corner region protrudes outward and the case is deformed due to excessive stress can be reduced, and high reliability can be given to the battery cell.

[0015] According to some embodiments of the present application, 0 < E ≤ 16.7% is satisfied.

[0016] In the above solution, by limiting the degree E by which the second thickening portion is thicker than the second main body portion to be 16.7% or less, the problems of cracking due to stress concentration and deformation due to excessive stress can be improved together, and the weight of the case can be effectively controlled, which contributes to the improvement of the weight energy density of the battery cell.

[0017] According to some embodiments of the present application, in the first direction, when the distance from one end away from the opening of the second thickening portion to the opening is L1, 0 < L1 ≤ 20 mm is satisfied.

[0018] In the above solution, in the first direction, by providing a second thickening portion in a region within 20 mm below the opening of the corner region, the strength of the portion corresponding to the opening of the corner region can be effectively improved, and the risk that stress concentrates on the portion corresponding to the opening of the corner region in the case manufacturing process due to thickening the first wall and the corner region cracks can be reduced, giving the battery cell high reliability.

[0019] According to some embodiments of the present application, in the first direction, if the distance from one end away from the opening of the first thickening portion to the opening is L2, then 0 < L2 ≤ 20 mm is satisfied.

[0020] In the above solution, in the first direction, by providing a first thickening portion in a region within 20 mm below the opening of the first wall, the strength of the portion corresponding to the opening of the first wall can be effectively improved, and since a heat - affected region with low strength is formed at the welding portion corresponding to the opening of the case in the first wall, the risk that the first wall is easily cracked when receiving an impact can be reduced, giving the battery cell high reliability.

[0021] According to some embodiments of the present application, the area of the outer surface of the first wall is larger than the area of the outer surface of the second wall.

[0022] In the above solution, by providing a first thickening portion on the first wall with a large outer surface area, the risk that the case is easily cracked when receiving an impact can be effectively improved, giving the battery cell high reliability.

[0023] According to some embodiments of the present application, the case includes two first walls provided opposite to each other in the second direction, and two second walls provided opposite to each other in the third direction, and the second direction and the third direction are perpendicular to the first direction mutually. The adjacent first wall and second wall are connected through the corresponding corner region, and the first wall, the second wall and the corner region together enclose to form an opening.

[0024] In the above solution, the case may have a quadrilateral structure. By thickening two wall portions provided opposite to each other in the second direction, that is, by providing the first ribbing portion, the structural strength of the case can be effectively improved, and the risk that the case cracks when receiving an impact can be reduced. At the same time, by thickening the corner region between two adjacent wall portions, that is, by providing the second ribbing portion, the problem that the corner region cracks due to stress concentration can be improved, and high reliability can be given to the battery cell.

[0025] According to some embodiments of the present application, the second wall includes a third main body portion and a third ribbing portion arranged in the first direction. The third main body portion is farther from the opening than the third ribbing portion, and the maximum thickness of the third ribbing portion is greater than the thickness of the third main body portion.

[0026] In the above solution, by providing the third ribbing portion with the largest thickness on the second wall, the risk that a heat-affected region with low strength is formed in the case due to welding and the second wall cracks with insufficient strength when receiving an impact can be improved, and high reliability can be given to the battery cell.

[0027] According to some embodiments of the present application, the maximum thickness of the second ribbing portion is greater than the maximum thickness of the third ribbing portion.

[0028] In the above solution, by making the maximum thickness of the second ribbing portion greater than the maximum thickness of the third ribbing portion, the strength of the portion corresponding to the opening in the corner region can be effectively increased, so that the overall thickness of the case can be effectively increased, the risk that the case cracks when receiving an impact can be reduced, and the problem that stress concentrates in the corner region and the corner region cracks in the case manufacturing process can be effectively improved, and high reliability can be given to the battery cell.

[0029] According to some embodiments of the present application, if the maximum thickness of the second ribbing portion is T1, the thickness of the second main body portion is T2, the maximum thickness of the third ribbing portion is t3, and the thickness of the third main body portion is t4, then E≧G is satisfied, where E=(T1-T2) / T2 and G=(t3-t4) / t4. [[ID= 21]]

[0030] In the above solution, by limiting the thickness E of the second main body part of the second thickening part to be greater than or equal to the thickness G of the third main body part of the third thickening part, the problem that stress concentrates on the part corresponding to the opening in the corner area and the corner area cracks in the case manufacturing process due to the installation of the third thickening part can be effectively improved, and the battery cell can be given high reliability.

[0031] According to some embodiments of the present application, in the first direction, if the distance from one end away from the opening of the third thickening part to the opening is L3, then 0 < L3 ≤ 20 mm is satisfied.

[0032] In the above solution, in the first direction, by providing the third thickening part in the area within 20 mm below the opening of the second wall, the strength of the part corresponding to the opening of the second wall can be effectively improved, and the risk that the second wall is easily cracked when receiving an impact can be reduced, and the battery cell can be given high reliability.

[0033] According to some embodiments of the present application, the battery cell further includes an end cover for closing the opening. The third thickening part includes a first segment and a second segment connected to each other. The first segment, the second segment and the third main body part are distributed in sequence in the first direction. The maximum thickness of the second segment is greater than the thickness of the third main body part, the maximum thickness of the second segment is greater than the maximum thickness of the first segment, and the end cover is connected to the first segment.

[0034] In the above solution, by making the thickness of the second segment of the third thickening part greater than the thickness of the third main body part, the strength of the second wall can be effectively improved, and the risk that the second wall cracks when receiving an impact can be reduced, and the battery cell can be given high reliability.

[0035] According to some embodiments of the present application, a first stepped surface is formed between the second segment and the first segment, and the end cover overlaps and is connected to the first stepped surface.

[0036] In the above solution, the first stepped surface formed between the second segment and the first segment allows the end cover to overlap and connect to the first stepped surface, contributing to the positioning and attachment of the end cover. At the same time, the first stepped surface can support the end cover, reducing the risk of the end cover falling off and further enhancing the reliability of the battery cell.

[0037] According to some embodiments of this application, the battery cell further includes an end cover that closes an opening, the second thickening portion includes a third segment and a fourth segment connected to each other, the third segment, the fourth segment and the second body portion are distributed sequentially in a first direction, the maximum thickness of the fourth segment is greater than the thickness of the second body portion, the maximum thickness of the fourth segment is greater than the maximum thickness of the third segment, and the end cover is connected to the third segment.

[0038] In the above solution, by making the thickness of the fourth segment of the second reinforced portion greater than the thickness of the second main body portion, the strength of the corner region is effectively improved, reducing the risk of the corner region cracking due to impact or stress concentration during demolding, thereby providing high reliability to the battery cell.

[0039] According to some embodiments of this application, a second stepped surface is formed between the fourth segment and the third segment, and the end cover is connected to overlap the second stepped surface.

[0040] In the above solution, the second stepped surface formed between the fourth segment and the third segment allows the end cover to overlap and connect to the second stepped surface, contributing to the positioning and attachment of the end cover. At the same time, the second stepped surface supports the end cover, reducing the risk of the end cover falling off and further enhancing the reliability of the battery cell.

[0041] According to some embodiments of this application, the battery cell further includes an end cover welded to a second thickened portion to form a welded area, wherein the average crystal grain size of the portion of the second thickened portion other than the welded area is greater than the average crystal grain size of the second main body, and the average crystal grain size is the average crystal grain size in a first direction of the crystal grains.

[0042] In the above solution, by limiting the average crystal grain size of the portion of the second reinforced section other than the welded area to be larger than the average crystal grain size of the second main body, it contributes to increasing the strength of the corner region, giving the second reinforced section high strength, reducing the risk of the corner region cracking near the welded area due to impact, and the risk of the corner region cracking due to stress concentration during demolding, thereby providing high reliability to the battery cell.

[0043] According to some embodiments of this application, in a cross-section parallel to the first direction of the corner region, the portion of the second thickened portion located below the welded region has 15 or more crystalline grains in the width direction of the cross-section.

[0044] In the above solution, the number of crystal grains in the width direction of the cross-section is 15 This contributes to increasing the strength of the second reinforced section, reducing the risk of the case cracking and improving the reliability of the battery cells.

[0045] According to some embodiments of this application, the average crystal grain size range of the portion of the second thickened section other than the welded area is 70 micrometers to 1200 micrometers, and / or the average crystal grain size range of the second main body is 30 micrometers to 1000 micrometers, and / or the maximum wall thickness of the end cover is 0.25 millimeters to 3 millimeters.

[0046] In the above solution, the average crystal particle size of the second reinforced portion and / or the average crystal particle size of the second main body portion satisfy the above relationship, thereby contributing to an increase in the strength of the second reinforced portion and providing high reliability to the battery cell.

[0047] In a second embodiment, the present application further provides a battery including the battery cell of the first embodiment.

[0048] In a third embodiment, the application further provides an energy storage device including a battery cell according to the first embodiment.

[0049] In a fourth embodiment, the present application further provides an electrical device that includes a battery cell according to the first embodiment and provides electrical energy.

[0050] Additional aspects and advantages of this application are partially shown in the following description, and other parts will become apparent from the following description or be understood by practice of this application. [Brief explanation of the drawing]

[0051] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments are briefly introduced below. It should be understood that these drawings only illustrate one embodiment of this application and should not be considered limiting in scope. Those skilled in the art can obtain other relevant drawings based on these without any creative work.

[0052] [Figure 1] These are schematic diagrams of vehicles in some embodiments of this application. [Figure 2] This is a schematic diagram of an energy storage device in some embodiments of this application. [Figure 3] These are exploded views of batteries in some embodiments of this application. [Figure 4] These are exploded views of the local structure of a battery cell in some embodiments of this application. [Figure 5] This is a front view of a battery cell in some embodiments of this application. [Figure 6] This is a cross-sectional view along the AA direction in Figure 5. [Figure 7] This is a magnified view of area B in Figure 6. [Figure 8]Figure 5 is a cross-sectional view along the CC direction. [Figure 9] This is a magnified view of area D in Figure 8. [Figure 10] This is a schematic diagram of the internal structure of a battery cell in some embodiments of this application. [Figure 11] This is a magnified view of location H in Figure 10. [Figure 12] This is a magnified view of area L in Figure 4. [Figure 13] These are schematic diagrams of end covers and corner regions in some embodiments of this application. [Modes for carrying out the invention]

[0053] The following describes in detail embodiments of the technical proposal of this application with reference to the drawings. The following embodiments are merely examples, intended to provide a clearer explanation of the technical proposal of this application, and should not limit the scope of protection of this application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application pertains. The terms used herein are solely for the purpose of describing specific embodiments and are not intended to limit this application. Terms such as “includes” and “composes,” and any variations thereof, in the description, claims, and brief description of the drawings above, are intended to cover non-exclusive inclusion.

[0055] In the descriptions of the embodiments of this application, technical terms such as "first," "second," etc., are merely used to distinguish different subjects and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features shown, a specific order, or a primary-secondary relationship. In the descriptions of the embodiments of this application, unless otherwise clearly and specifically limited, "multiple" means two or more.

[0056] Where the “Examples” are described herein, it means that certain features, structures, or properties described in association with the Examples may be included in at least one Example of this Application. The wording appearing elsewhere in the Specification does not necessarily refer to the same Example, nor does it mean that an Example is exclusively independent or alternative to another. It will be explicitly or implicitly understood by those skilled in the art that the Examples described herein may be combined with other Examples.

[0057] In the description of the embodiments of this application, the term "and / or" is merely used to describe the relationship between related objects, and means that there may be three types of relationships. For example, A and / or B can mean that A exists, A and B exist simultaneously, or B exists. In addition, the symbol " / " in this specification generally means that the preceding and following related objects are in an "or" relationship.

[0058] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple sheets" refers to two or more sheets (including two sheets).

[0059] In the description of the embodiments of this application, the directions or positional relationships indicated by technical terms such as "center," "vertical direction," "horizontal direction," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" are directions or positional relationships shown based on the drawings, and are merely for the purpose of simplifying the description and making it easier to explain the embodiments of this application. They do not explicitly or implicitly suggest that the indicated device or element necessarily has a specific direction, or is composed and operated in a specific direction, and should not be understood as limiting the embodiments of this application.

[0060] In the descriptions of the embodiments of this application, unless otherwise explicitly specified or limited, technical terms such as "attach," "connect," "join," and "fix" should be understood in a broad sense. For example, they may refer to fixed connections, removable connections, or integrated connections. They may also refer to mechanical or electrical connections. Furthermore, they may refer to direct connections, indirect connections via an intermediate mediator, internal communication between two elements, or interaction relationships between two elements. Those skilled in the art will be able to understand the specific meaning of the above terms in the embodiments of this application depending on the specific circumstances.

[0061] In this application, the battery cell may include, but is not limited to, 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. The battery cell may be a rectangular parallelepiped or other shape, etc., but is not limited to, a shape, etc. The battery described in the embodiments of this application is a single physical module containing one or more battery cells to provide higher voltage and capacity. The battery generally comprises a box for packaging one or more battery cells. The box can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0062] A battery cell comprises an electrode assembly and an electrolyte, the electrode assembly consisting of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell operates primarily by the movement (e.g., insertion and removal) of metal ions between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer, with the positive electrode active material layer coated on the surface of the positive electrode current collector. A positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector with the positive electrode active material layer and becomes a positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer, with the negative electrode active material layer coated on the surface of the negative electrode current collector. A negative electrode current collector without the negative electrode active material layer protrudes from the negative electrode current collector with the negative electrode active material layer and becomes a negative electrode tab. Copper is an example of a material for the negative electrode current collector, and carbon or silicon is an example of a negative electrode active material. To prevent melting when a large current flows, there are multiple positive electrode tabs, which are laminated integrally, and multiple negative electrode tabs, which are laminated integrally. The separator material may be PP (polypropylene) or PE (polyethylene), etc. The electrode assembly may be a wound structure or a laminated structure, but is not limited to these in the embodiments of this application. The battery cell further includes an electrode assembly, a case for providing electrolyte, and an end cover. In the first direction, an opening is formed in the case, and the end cover is welded to the case to close the opening in the case. In some embodiments, in the circumferential direction of the opening, the case includes a first wall, a corner region and a second wall connected in sequence, the first wall and the second wall being adjacent and transitionally connected via the corner region.

[0063] To advance battery technology, it is necessary to consider various design elements, such as energy density, cycle life, discharge capacity, and charge / discharge rate, simultaneously, as well as battery reliability. For battery cells, after the end cover is welded to the case, a heat-affected zone (HIR) is usually formed below the molten pool, which reduces the case strength. Therefore, when the battery cell is subjected to impact or internal expansion, the case can crack, rendering the battery useless. To improve this problem, the walls of the battery case are currently thickened or thickened locally, for example, by thickening the area corresponding to the opening in the first wall of the case to improve the case strength. However, such cases are manufactured using a tensile molding process, and during elastic demolding of the case, stress concentrates in the area corresponding to the opening in the corner region, making the corner region prone to cracking, which affects the reliability of the battery cell and, furthermore, the reliability of the battery as a whole.

[0064] In view of the above, in order to improve the problem that corner regions crack due to stress concentration during elastic demolding of the case, affecting the reliability of the battery cell, some embodiments of this application provide a battery cell including a case. The case has an opening formed at an end along a first direction. In the circumferential direction of the opening, the case includes a first wall, a corner region and a second wall connected in order. The first wall comprises a first body portion and a first reinforcement portion aligned in a first direction, the first body portion being further away from the opening than the first reinforcement portion, and the first reinforcement portion having a maximum thickness greater than the thickness of the first body portion. The corner region comprises a second body portion and a second reinforcement portion aligned in a first direction, the second body portion being further away from the opening than the second reinforcement portion, and the second reinforcement portion having a maximum thickness greater than the thickness of the second body portion.

[0065] In the above solution, by providing a first reinforced section with a large maximum thickness on the first wall, the risk of the first wall cracking due to insufficient strength when subjected to impact, caused by the formation of a heat-affected zone with low strength due to welding, can be improved, thereby ensuring high reliability for the battery. At the same time, by providing a second reinforced section with a large maximum thickness in the corner region, the strength of the part corresponding to the opening in the corner region is increased, and the installation of the first reinforced section improves the problem of the corner region cracking due to stress concentration during elastic demolding of the case, thereby ensuring high reliability for the battery cell.

[0066] The technical means described in the embodiments of this application can be applied to batteries, energy storage devices equipped with battery modules, and electrical devices using battery modules.

[0067] The energy storage device may include multiple battery cells, which may be connected in series, in parallel, or in a mixed configuration. The energy storage device may also be a device capable of storing electrical energy, such as an energy storage cabinet or energy storage box.

[0068] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, aircraft, electric toys, and power tools. Vehicles may be new energy vehicles, which may include battery-powered vehicles, hybrid vehicles, or range-extender vehicles. Aircraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include, for example, fixed or portable electric toys such as game consoles, electric car toys, electric boat toys, and electric airplane toys. Power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The embodiments of this application do not particularly limit the above-mentioned electrical devices.

[0069] For the sake of explanation, the following embodiments will be described using the vehicle 1000 as an example of the electrical device.

[0070] Figure 1 is a schematic diagram of vehicle 1000 in some embodiments of this application.

[0071] 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 power supply of the battery 100 to the motor 300. For example, the battery 100 can be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 is used to supply power to the vehicle 1000, for example, as the operating power source for the vehicle 1000, used in the vehicle 1000's circuit system, for example, to meet the demands for operating power during starting, navigation, and driving of the vehicle 1000. In another embodiment of this application, the battery 100 can also provide driving power to the vehicle 1000 as a drive power source, replacing all or part of gasoline or natural gas, in addition to being the operating power source for the vehicle 1000.

[0072] Figure 2 is a schematic diagram of an energy storage device in some embodiments of the present application. The energy storage device 2000 may be a device for storing electrical energy, and for example, the energy storage device 2000 may include an energy storage cabinet, which includes a cabinet 2001 and one or more batteries 100 provided in the cabinet. The cabinet 2001 may include a cabinet body and a cabinet door, one or more batteries 100 are provided in the cabinet body, and the cabinet door closes the opening of the cabinet body, thereby positioning one or more batteries 100 in a closed space and reducing the interference effect of external materials on the batteries 100.

[0073] Please refer to Figure 3, which is a three-dimensional exploded view of battery 100 in some embodiments of this application.

[0074] The battery 100 comprises a battery cell 10 and a box 20 that houses the battery cell 10. Here, the box 20 provides a housing space for the battery cell 10, and various structures can be adopted. In some embodiments, the box 20 may comprise a first box section 21 and a second box section 22 that overlap each other and together define a housing space for housing the battery cell 10. The second box section 22 may be a hollow structure with an opening 11a at one end, and the first box section 21 may be a plate-like structure. The first box section 21 covers the opening 11a side of the second box section 22 so that the first box section 21 and the second box section 22 together define a housing space. Both the first box section 21 and the second box section 22 may be hollow structures with an opening 11a at one end, and the opening 11a side of the first box section 21 covers the opening 11a side of the second box section 22. Of course, the box 20 formed by the first box section 21 and the second box section 22 may have various shapes such as a cylinder or a rectangular parallelepiped.

[0075] In the battery 100, there may be one or more battery cells 10, and each battery cell 10 can be fixed to the box 20 via a connecting member (for example, a bolt), or it can be fixed to the box 20 by adhesive.

[0076] Several embodiments of this application provide a battery cell 10, with reference to Figures 4-11. Figure 4 is an exploded view of the local structure of the battery cell 10 in several embodiments of this application; Figure 5 is a front view of the battery cell 10 in several embodiments of this application; Figure 6 is a cross-sectional view along direction AA in Figure 5; Figure 7 is an enlarged view of location B in Figure 6; Figure 8 is a cross-sectional view along direction CC in Figure 5; Figure 9 is an enlarged view of location D in Figure 8; Figure 10 is a schematic diagram of the internal structure of the battery cell 10 in several embodiments of this application; and Figure 11 is an enlarged view of location H in Figure 10.

[0077] The battery cell 10 includes a case 11. The case 11 has an opening 11a formed at its end along a first direction z. In the circumferential direction of the opening 11a, the case 11 includes a first wall 110, a corner region 112, and a second wall 113 connected in order. The first wall 110 comprises a first main body portion 1100 and a first thickened portion 1101 arranged in the first direction z, the first main body portion 1100 being further away from the opening 11a than the first thickened portion 1101, and the first thickened portion 1101 having a maximum thickness greater than the thickness of the first main body portion 1100. The corner region 112 comprises a second main body portion 1120 and a second thickened portion 1121 arranged in the first direction z, the second main body portion 1120 being further away from the opening 11a than the second thickened portion 1121, and the second thickened portion 1121 having a maximum thickness greater than the thickness of the second main body portion 1120.

[0078] In some embodiments, the battery cell 10 may include a case 11 and an end cover 14, wherein in a first direction z, the case 11 has an opening 11a, the electrode assembly 12 is located inside the case 11, and the end cover 14 is connected to the case 11 and closes the opening 11a, thereby positioning the electrode assembly 12 in a closed space. In some embodiments, the end cover 14 may be provided with electrode terminals 13 that are connected to tabs on the electrode assembly 12 to enable current input and output. In some embodiments, the end cover 14 may be provided with an electrolyte injection hole, through which the electrolyte can be injected into the case 11. In some embodiments, the end cover 14 can be connected to the case 11 by riveting, welding, or screwing.

[0079] In some embodiments, the case 11 may include a plurality of interconnected walls in the circumferential direction of the opening 11a of the case 11. For example, in the circumferential direction of the opening 11a, the case 11 includes a first wall 110, a corner region 112, and a second wall 113 connected in sequence, wherein the first wall 110 and the second wall 113 are adjacent and transitionally connected via the corner region 112. For example, if the case 11 is a quadrilateral or approximately quadrilateral, it may include two opposing first walls 110 in a second direction x, and two opposing second walls 113 in a third direction y, wherein the second direction x and the third direction y are perpendicular to each other, and adjacent first walls 110 and second walls 113 are connected via corresponding corner regions 112, and the first walls 110, second walls 113, and corner regions 112 together enclose and form the opening 11a. In some embodiments, the cross-section of the corner region 112 may be arc-shaped, thereby causing the first wall 110 and the second wall 113 to transition in an arc. In another embodiment, the shape of the cross-section of the corner region 112 does not have to be arc-shaped, and may be polygonal so that the first wall 110 and the second wall 113 transition smoothly.

[0080] In some embodiments, the first direction z may be parallel to the height direction of the battery cell 10, the second direction x may be the thickness direction of the battery cell 10, and the third direction y may be the width direction of the battery cell 10.

[0081] In some embodiments, the outer surface area of ​​the first wall 110 may be larger than the outer surface area of ​​the second wall 113. In other embodiments, the outer surface area of ​​the first wall 110 may be smaller than the outer surface area of ​​the second wall 113. In other embodiments, the outer surface area of ​​the first wall 110 may be equal to the outer surface area of ​​the second wall 113.

[0082] In some embodiments, Case 11 can be manufactured by a tensile forming process, which may include a tensile process and a demolding process. Generally, the tensile process involves applying stress to a metal sheet material at the tensile processing location to deform it. During the tensile process, it is necessary to control parameters such as the magnitude, speed, and time of the stress to avoid problems such as cracking or uneven stress in the metal sheet material. Tensile force is generally applied by hydraulic or mechanical drive. Generally, the demolding process is also called elastic demolding and may refer to the process of sliding the finished product out of the mold after tensile processing is complete. Pneumatic or mechanical demolding methods are generally employed.

[0083] The statement "The first wall 110 comprises a first main body portion 1100 and a first reinforced portion 1101 arranged in a first direction z, and the first main body portion 1100 is further away from the opening 11a than the first reinforced portion 1101" can be understood as the first main body portion 1100 and the first reinforced portion 1101 being arranged relative to each other in the first direction z, with the first main body portion 1100 being further away from the opening 11a than the first reinforced portion 1101.

[0084] For example, in a possible scenario, the first main body portion 1100 and the first reinforced portion 1101 are connected in a first direction z, and the first reinforced portion 1101 is connected to an end cover at the end of the first reinforced portion 1101 away from the first main body portion 1100 where an opening 11a is formed; or in another possible scenario, the first wall 110 further includes a first connecting segment, and the first connecting segment, the first reinforced portion 1101 and the first main body portion 1100 are distributed in a first direction z, and the first connecting segment is connectable to an end cover 14 at the end of the first connecting segment where an opening 11a is formed, and the thickness of the first connecting segment may be greater than, equal to, or less than the maximum thickness of the first reinforced portion 1101.

[0085] The statement "the maximum thickness of the first reinforced portion 1101 is greater than the thickness of the first main body portion 1100" can be understood as either the maximum thickness of the first reinforced portion 1101 being greater than the thickness of the first main body portion 1100, or the strength of the first reinforced portion 1101 being greater than the strength of the first main body. In some embodiments, the first reinforced portion 1101 has a uniform thickness structure, and its thickness may be greater than the thickness of the first main body portion 1100. In other embodiments, the first reinforced portion 1101 does not have to have a uniform thickness structure, and the thickness of the thickest part of its wall is greater than the maximum thickness of the first main body portion 1100. In some embodiments, the first reinforced portion 1101 is connected to the first main body portion 1100, and the thickness of the boundary portion with the first main body portion 1100 may gradually increase, thereby providing a gradual transition between the first reinforced portion 1101 and the first main body portion 1100.

[0086] In some embodiments, the first thickened portion 1101 may protrude from the inside of the first main body portion 1100, that is, the portion of the first thickened portion 1101 that protrudes from the first main body portion 1100 may be located inside the case 11. In another embodiment, the first thickened portion 1101 may protrude from the outside of the first main body portion 1100, that is, the portion of the first thickened portion 1101 that protrudes from the first main body portion 1100 may be located outside the case 11. In yet another embodiment, the first thickened portion 1101 may protrude from both the outside and the inside of the first main body portion 1100, that is, a portion of the first thickened portion 1101 that protrudes from the first main body portion 1100 may be located outside the case 11, and a portion may be located inside the case 11.

[0087] In some embodiments, the first main body portion 1100 may have a uniform thickness structure. In other embodiments, the first main body portion 1100 may not have a uniformly distributed thickness and may have a non-uniform thickness structure.

[0088] The statement "The corner region 112 comprises a second main body portion 1120 and a second thickening portion 1121 arranged in a first direction z, and the second main body portion 1120 is further away from the opening 11a than the second thickening portion 1121" can be understood as the second main body portion 1120 and the second thickening portion 1121 being arranged relative to each other in the first direction z, with the second main body portion 1120 being further away from the opening 11a than the second thickening portion 1121.

[0089] For example, in a possible scenario, the second main body portion 1120 and the second reinforced portion 1121 are connected in a first direction z, and the second reinforced portion 1121 is connected to an end cover at the end of the second reinforced portion 1121 away from the second main body portion 1120 where an opening 11a is formed. Alternatively, in another possible scenario, the corner region 112 further includes a second connecting segment, and the second connecting segment, the second main body portion 1120, and the second reinforced portion are distributed in a first direction z, and the second connecting segment is connectable to an end cover at the end of the second connecting segment where an opening 11a is formed.

[0090] The statement "the maximum thickness of the second reinforced portion 1121 is greater than the thickness of the second main body portion 1120" can be understood as either the maximum thickness of the second reinforced portion 1121 being greater than the thickness of the second main body portion 1120, or the strength of the second reinforced portion 1121 being greater than the strength of the second main body. In some embodiments, the second reinforced portion 1121 has a uniform thickness structure, and its thickness may be greater than the thickness of the second main body portion 1120. In other embodiments, the second reinforced portion 1121 does not have a uniform thickness structure, and the thickness of the thickest part of its wall is greater than the maximum thickness of the second main body portion 1120. In some embodiments, the second reinforced portion 1121 is connected to the second main body portion 1120, and the thickness of the boundary portion with the second main body portion 1120 may gradually increase, thereby providing a gradual transition between the second reinforced portion 1121 and the second main body portion 1120.

[0091] In some embodiments, the second main body portion 1120 may have a uniform thickness structure. In other embodiments, the second main body portion 1120 may not have a uniformly distributed thickness and may have a non-uniform thickness structure.

[0092] In some embodiments, the second thickened portion 1121 may protrude from the inside of the second main body portion 1120, that is, the portion of the second thickened portion 1121 that protrudes from the second main body portion 1120 may be located inside the case 11. In other embodiments, the second thickened portion 1121 may protrude from the outside of the second main body portion 1120, that is, the portion of the second thickened portion 1121 that protrudes from the second main body portion 1120 may be located outside the case 11. In yet another embodiment, the second thickened portion 1121 may protrude from both the outside and the inside of the second main body portion 1120, that is, a portion of the second thickened portion 1121 that protrudes from the second main body portion 1120 may be located outside the case 11, and a portion may be located inside the case 11.

[0093] In some embodiments, the relationship between the maximum thickness of the first reinforced portion 1101 and the maximum thickness of the second reinforced portion 1121 is not limited, and possible situations include the maximum thickness of the first reinforced portion 1101 being less than the maximum thickness of the second reinforced portion 1121, the maximum thickness of the first reinforced portion 1101 being greater than the maximum thickness of the second reinforced portion 1121, or the maximum thickness of the first reinforced portion 1101 being equal to the maximum thickness of the second reinforced portion 1121.

[0094] In the above solution, by providing a first thickened portion 1101 with a large maximum thickness on the first wall 110, a heat-affected zone with low strength is formed in the case 11 due to welding, which improves the problem of the first wall 110 cracking with insufficient strength when subjected to impact, thereby providing high reliability to the battery 100. At the same time, by providing a second thickened portion 1121 with a large maximum thickness on the corner region 112, the strength of the part corresponding to the opening 11a of the corner region 112 is increased, and the problem of the corner region 112 cracking due to stress concentrating on the part corresponding to the opening 11a of the corner region 112 when the case 11 is demolded due to the installation of the first thickened portion 1101 is improved, thereby providing high reliability to the battery cell 10.

[0095] According to some embodiments of this application, the maximum thickness of the second thickened portion 1121 is greater than the maximum thickness of the first thickened portion 1101.

[0096] The statement "the maximum thickness of the second reinforced portion 1121 is greater than the maximum thickness of the first reinforced portion 1101" can be understood as the maximum thickness of the thickened portion of the corner region 112 being greater than the maximum thickness of the thickened portion of the first wall 110, or as the strength of the second reinforced portion 1121 being greater than the strength of the first reinforced portion 1101.

[0097] In some embodiments, the minimum thickness of the second thickened portion 1121 may be greater than the maximum thickness of the first thickened portion 1101. In other embodiments, the minimum thickness of the second thickened portion 1121 may be less than or equal to the maximum thickness of the first thickened portion 1101. In other embodiments, the minimum thickness of the second thickened portion 1121 may be less than the minimum thickness of the first thickened portion 1101. squid, or equivalent It's fine.

[0098] In the above solution, by making the maximum thickness of the second reinforced portion 1121 greater than the maximum thickness of the first reinforced portion 1101, the strength of the portion corresponding to the opening 11a of the corner region 112 can be effectively increased. This effectively increases the overall thickness of the case 11, reduces the risk of the case 11 cracking due to impact, and effectively improves the problem of the corner region 112 cracking due to stress concentration during the manufacturing process of the case 11, thereby providing the battery cell 10 with high reliability.

[0099] In another embodiment, the maximum thickness of the second thickened portion 1121 may be less than the maximum thickness of the first thickened portion 1101. In another embodiment, the maximum thickness of the second thickened portion 1121 may be less than the minimum thickness of the first thickened portion 1101.

[0100] For some embodiments of this application, please refer to Figures 7 and 9. If the maximum thickness of the second reinforced portion 1121 is T1, the thickness of the second main body portion 1120 is T2, the maximum thickness of the first reinforced portion 1101 is t1, and the thickness of the first main body portion 1100 is t2, then E≧F is satisfied, and E=(T1-T2) / T2, F=(t1-t2) / t2.

[0101] In some embodiments, the corner region 112 of case 11 can be considered as a region that forms a second thickened portion 1121 by locally thickening it with respect to the second main body portion 1120, where T1-T2 is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body portion 1120, and E is the ratio of the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body portion 1120 to the thickness of the upper second main body portion 1120, that is, E can be considered as the degree to which the second thickened portion 1121 is thicker than the second main body portion 1120.

[0102] In some embodiments, the first wall 110 of case 11 can be considered as a portion that forms a first reinforced portion 1101 by locally thickening it with respect to the first main body portion 1100, where t1-t2 is the difference between the maximum thickness of the first reinforced portion 1101 and the thickness of the first main body portion 1100, and F is the ratio of the difference between the maximum thickness of the first reinforced portion 1101 and the thickness of the first main body portion 1100 to the thickness of the first main body portion 1100, that is, F can be considered as the degree to which the first reinforced portion 1101 is thicker than the first main body portion 1100.

[0103] "E≧F" means the second of the second meat thickening section 1121 Main unit It may be understood that the degree of thickness of the first thickened portion 1101 is greater than or equal to the degree of thickness of the first main body portion 1100 of the first thickened portion 1101.

[0104] In the above solution, by limiting the degree of thickness E of the second reinforced portion 1121 to that of the second main body portion 1120 to a degree of thickness F or greater than that of the first reinforced portion 1101 to that of the first main body portion 1100, the problem of the corner region 112 cracking due to stress concentration during the manufacturing process of the case 11 caused by the installation of the first reinforced portion 1101 can be effectively improved, thereby providing the battery cell 10 with high reliability.

[0105] In another embodiment, the degree to which the second thickened portion 1121 is thicker than the second portion is less than the degree to which the first thickened portion 1101 is thicker than the first main body portion 1100.

[0106] According to some embodiments of the present application, when the maximum thickness of the second thickening portion 1121 is T1 and the thickness of the second main body portion 1120 is T2, 0 < E < 30% is satisfied, and E = (T1 - T2) / T2.

[0107] In some embodiments, the corner region 112 of the case 11 can be regarded as a site for forming the second thickening portion 1121 by locally thickening with respect to the second main body portion 1120. T1 - T2 is the difference between the maximum thickness of the second thickening portion 1121 and the thickness of the second main body portion 1120, and E is the ratio of the difference between the maximum thickness of the second thickening portion 1121 and the thickness of the second main body portion 1120 to the thickness of the second main body portion 1120. That is, E can be regarded as the degree to which the second thickening portion 1121 is thicker than the second main body portion 1120.

[0108] In some embodiments, the value of E may satisfy being greater than 0 and less than 30%. As an example, the value of E may be 1%, 2%, 3%, 4%... 28%, 29%, any value between two adjacent values or any value between 29% and 30%.

[0109] In some embodiments, T2 may be 0.6 mm, and T1 may be a value greater than 0.6 mm. For example, T1 may be 0.65%, 0.7% or 0.75%, and the corresponding values of E are 8.3%, 16.7% and 25% respectively.

[0110] In the above solution, by limiting the degree E by which the second thickening portion 1121 is thicker than the second main body portion 1120, the strength of the corner region 112 can be improved, the risk of cracking of the corner region 112 due to stress concentration can be reduced, and the risk of the corner region 112 protruding outward due to excessive stress and the case being deformed can be reduced, giving the battery cell 10 high reliability.

[0111] According to some embodiments of the present application, 0 < E ≤ 16.7% is satisfied. <0000​In some embodiments, the value of E may satisfy being greater than 0 and not exceeding 16.7%. As an example, the value of E may be 1%, 2%, 3%, 4%... 16%, 16.7% or any value between two adjacent values.

[0113] In the above solution, by limiting the degree E by which the second main body part 1120 of the second thickening part 1121 is thicker to 16.7% or less, it is possible to improve both the problem of cracking due to stress concentration and deformation due to excessive stress, and at the same time, effectively control the weight of the case 11, contributing to an improvement in the weight energy density of the battery cell 10.

[0114] According to some embodiments of the present application, in the first direction z, when the distance from one end away from the opening 11a of the second thickening part 1121 to the opening 11a is L1, 0 < L1 ≤ 20 mm is satisfied.

[0115] [[ID= - 12]]In some embodiments, the value of L1 may be greater than 0 and not exceed 20 mm. As an example, the value of L1 may be 1 mm, 2 mm, 3 mm, 4 mm... 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value between two adjacent values or any value between 0 mm and 1 mm.

[0116] In some embodiments, the first direction z can be regarded as the vertical direction. "Taking the distance from one end away from the opening 11a of the second thickening part 1121 to the opening 11a as L1" means that the second main body part 1120 is Open below and separated from the opening by L1, and the second thickening part 1121 is located above the second main body part 1120, or in the first direction z, a boundary line may be defined at a part away from the opening 11a, and it may be understood that the second thickening part 1121 is located above the boundary line and the second main body part 1120 is located below the boundary line.

[0117] In the above solution, in the first direction z, by providing the second thickening portion 1121 in the region within 20 mm below the opening 11a of the corner region 112, the strength of the portion corresponding to the opening 11a of the corner region 112 can be effectively improved, and the risk that stress concentrates on the portion corresponding to the opening 11a of the corner region 112 and the corner region 112 cracks due to thickening the first wall 110 can be reduced in the manufacturing process of the case 11, giving the battery cell 10 high reliability.

[0118] According to some embodiments of the present application, in the first direction z, when the distance from one end away from the opening 11a of the first thickening portion 1101 to the opening 11a is L2, 0 < L2 ≤ 20 mm is satisfied.

[0119] In some embodiments, the value of L1 may be greater than 0 and less than or equal to 20 mm. For example, the value of L1 may be 1 mm, 2 mm, 3 mm, 4 mm... 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value between two adjacent values or any value between 0 mm and 1 mm.

[0120] In some embodiments, the first direction z can be regarded as the vertical direction. "Taking the distance from one end away from the opening 11a of the first thickening portion 1101 to the opening 11a as L2" means that the first main body portion 1100 is Open below at a distance of L2 from the opening, and the first thickening portion 1101 is located above the first main body portion 1100, or in the first direction z, a boundary line may be defined at a portion away from the opening 11a, and the first thickening portion is understood to be located above the boundary line and the first main body portion 1100 is located below the boundary line.

[0121] In the above solution, by providing a second thickened portion 1121 in the area within 20 mm below the opening 11a of the corner region 112 in the first direction z, the strength of the part of the corner region 112 corresponding to the opening 11a is effectively improved, reducing the risk of the corner region 112 cracking due to stress concentrating in the part of the corner region 112 corresponding to the opening 11a during the manufacturing process of the case 11, thereby providing the battery cell 10 with high reliability.

[0122] According to some embodiments of this application, the area of ​​the outer surface of the first wall 110 is larger than the area of ​​the outer surface of the second wall 113.

[0123] In some embodiments, the outer surface of the first wall 110 may be the larger surface of the battery cell 10, and the expansion force generated inside the battery cell 10 during charging and discharging mainly acts on the first wall 110.

[0124] In the above solution, by providing the first thickened portion 1101 on the first wall 110 which has a large outer surface area, the risk of the case 11 becoming prone to cracking due to impact can be effectively reduced, and the battery cell 10 can be given high reliability.

[0125] In another embodiment of this application, the outer surface area of ​​the first wall 110 is equal to or less than the outer surface area of ​​the second wall 113.

[0126] Refer to Figure 4 for some embodiments of this application. Case 11 includes two opposing first walls 110 in a second direction x and two opposing second walls 113 in a third direction y, with the second direction x and third direction y being perpendicular to the first direction z. Adjacent first walls 110 and second walls 113 are connected via corresponding corner regions 112, and the first walls 110, second walls 113 and corner regions 112 together enclose an opening 11a.

[0127] In some embodiments, case 11 may be approximately rectangular parallelepiped in shape and its main structure includes two opposing first walls 110 and two opposing second walls 113, with the first walls 110 and second walls 113 being adjacent to each other. The adjacent first walls 110 and second walls 113 are transitionally connected via a corner region 112. In some embodiments, the corner region 112 may be an arc-shaped portion.

[0128] In the above solution, the case 11 may have a rectangular structure. By thickening two opposing wall sections in the second direction x, that is, by providing a first thickened section 1101, the structural strength of the case 11 can be effectively improved, reducing the risk of the case 11 cracking due to impact. At the same time, by thickening the corner region 112 between two adjacent wall sections, that is, by providing a second thickened section 1121, the problem of the corner region 112 cracking due to stress concentration can be improved, thereby providing the battery cell 10 with high reliability.

[0129] Refer to Figures 5-9 for some embodiments of this application. The second wall 113 comprises a third main body portion 1130 and a third thickening portion 1131 arranged in a first direction z, wherein the third main body portion 1130 is further away from the opening 11a than the third thickening portion 1131, and the maximum thickness of the third thickening portion 1131 is greater than the thickness of the third main body portion 1130.

[0130] The statement "The second wall 113 comprises a third main body portion 1130 and a third thickening portion 1131 arranged in the first direction z, and the third main body portion 1130 is further away from the opening 11a than the third thickening portion 1131" can be understood as the third main body portion 1130 and the third thickening portion 1131 being arranged in the first direction z, with the third main body portion 1130 being further away from the opening 11a than the third thickening portion 1131.

[0131] For example, in a possible scenario, the third main body portion 1130 and the third reinforced portion 1131 are connected in a first direction z, and the third reinforced portion 1131 is connected to an end cover at the end of the third reinforced portion 1131 away from the third main body portion 1130 where an opening 11a is formed, or in another possible scenario, the second wall 113 further includes a third connecting segment, and the third connecting segment, the third main body portion 1130 and the third Meat The parts are distributed sequentially in the first direction z, and the third connecting segment can be connected to the end cover 14 at the portion where the opening 11a is formed at the end of the third connecting segment.

[0132] The statement "the maximum thickness of the third reinforced portion 1131 is greater than the thickness of the third main body portion 1130" can be understood as either the maximum thickness of the third reinforced portion 1131 being greater than the thickness of the third main body portion 1130, or the strength of the third reinforced portion 1131 being greater than the strength of the third main body portion. In some embodiments, the third reinforced portion 1131 has a uniform thickness structure, and its thickness may be greater than the thickness of the third main body portion 1130. In other embodiments, the third reinforced portion 1131 does not have a uniform thickness structure, and the thickness of the thickest part of its wall is greater than the maximum thickness of the third main body portion 1130. In some embodiments, the third reinforced portion 1131 is connected to the third main body portion 1130, and the thickness of the boundary portion with the third main body portion 1130 may gradually increase, thereby providing a gradual transition between the third reinforced portion 1131 and the third main body portion 1130.

[0133] In some embodiments, the third thickened portion 1131 may protrude from the inside of the third main body portion 1130, that is, the portion of the third thickened portion 1131 that protrudes from the third main body portion 1130 may be located inside the case 11. In another embodiment, the third thickened portion 1131 may protrude from the outside of the third main body portion 1130, that is, the portion of the third thickened portion 1131 that protrudes from the third main body portion 1130 may be located outside the case 11. In yet another embodiment, the third thickened portion 1131 may protrude from both the outside and the inside of the third main body portion 1130, that is, a portion of the third thickened portion 1131 that protrudes from the third main body portion 1130 may be located outside the case 11, and a portion may be located inside the case 11.

[0134] In some embodiments, the third main body portion 1130 may have a uniform thickness structure. In other embodiments, the third main body portion 1130 may not have a uniformly distributed thickness and may have a non-uniform thickness structure.

[0135] According to some embodiments of this application, the maximum thickness of the second thickened portion 1121 is greater than the maximum thickness of the third thickened portion 1131.

[0136] The statement "the maximum thickness of the second reinforced portion 1121 is greater than the maximum thickness of the third reinforced portion 1131" can be understood as the maximum thickness of the thickened portion of the corner region 112 being greater than the maximum thickness of the thickened portion of the second wall 113, or as the strength of the second reinforced portion 1121 being greater than the strength of the third reinforced portion 1131.

[0137] In some embodiments, the minimum thickness of the second reinforced portion 1121 may be greater than the maximum thickness of the third reinforced portion 1131. In another embodiment, the minimum thickness of the second reinforced portion 1121 may be less than or equal to the maximum thickness of the third reinforced portion 1131. In yet another embodiment, the minimum thickness of the second reinforced portion 1121 may be less than the minimum thickness of the third reinforced portion 1131. squid, or equivalent It's fine.

[0138] In the above solution, by making the maximum thickness of the second reinforced portion 1121 greater than the maximum thickness of the third reinforced portion 1131, the strength of the portion corresponding to the opening 11a of the corner region 112 can be effectively increased. This effectively increases the overall thickness of the case 11, reduces the risk of the case 11 cracking due to impact, and effectively improves the problem of stress concentrating in the corner region 112 during the manufacturing process of the case 11, causing the corner region 112 to crack, thereby providing the battery cell 10 with high reliability.

[0139] In another embodiment, the maximum thickness of the second reinforced portion 1121 may be less than the maximum thickness of the third reinforced portion 1131. In another embodiment, the maximum thickness of the second reinforced portion 1121 may be less than the minimum thickness of the third reinforced portion 1131.

[0140] For some embodiments of this application, please refer to Figures 7 and 9. If the maximum thickness of the second reinforced portion 1121 is T1, the thickness of the second main body portion 1120 is T2, the maximum thickness of the third reinforced portion 1131 is t3, and the thickness of the third main body portion 1130 is t4, then E≧G is satisfied, and E=(T1-T2) / T2, G=(t3-t4) / t4.

[0141] In some embodiments, the corner region 112 of case 11 can be considered as a region that forms a second thickened portion 1121 by locally thickening it with respect to the second main body portion 1120, where T1-T2 is the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body portion 1120, and E is the ratio of the difference between the maximum thickness of the second thickened portion 1121 and the thickness of the second main body portion 1120 to the thickness of the second main body portion 1120, that is, E can be considered as the degree to which the second thickened portion 1121 is thicker than the second main body portion 1120.

[0142] In some embodiments, the second wall 113 of case 11 can be considered as a portion that forms a third thickened portion 1131 by locally thickening it with respect to the third main body portion 1130, where t3-t4 is the difference between the maximum thickness of the third thickened portion 1131 and the thickness of the third main body portion 1130, and G is the ratio of the difference between the maximum thickness of the third thickened portion 1131 and the thickness of the third main body portion 1130 to the thickness of the third main body portion 1130, that is, G can be considered as the degree to which the third thickened portion 1131 is thicker than the third main body portion 1130.

[0143] "E≧G" can be understood as meaning that the degree to which the second thickened portion 1121 is thicker than the second main body portion 1120 is greater than or equal to the degree to which the third thickened portion 1131 is thicker than the third main body portion 1130.

[0144] In the above solution, by limiting the degree of thickness E of the second reinforced portion 1121 to be greater than or equal to the degree of thickness G of the third reinforced portion 1131 to be greater than or equal to the third main body portion 1130, the stress on the corners during the manufacturing process of the case 11 due to the installation of the third reinforced portion 1131 is reduced. regionThe problem that the corner region 112 cracks concentratedly at the portion corresponding to the opening 11a can be effectively improved, and the battery cell 10 can be made highly reliable.

[0145] In another embodiment, the degree of thickness of the second build-up portion 1121 is smaller than the degree of thickness of the third build-up portion 1131 from the second main body portion 1120.

[0146] According to some embodiments of the present application, please refer to FIG. 4. In the first direction z, when the distance from one end away from the opening 11a of the third build-up portion 1131 to the opening 11a is L3, 0 < L3 ≤ 20 mm is satisfied.

[0147] In some embodiments, the value of L3 may be greater than 0 and less than or equal to 20 mm. For example, the value of L3 may be 1 mm, 2 mm, 3 mm, 4 mm... 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm or any value between two adjacent values or any value between 0 mm and 1 mm.

[0148] In some embodiments, the first direction z can be regarded as the vertical direction. "Taking the distance from one end away from the opening 11a of the third build-up portion 1131 to the opening 11a as L3" means that the third main body portion 1130 is Open below the opening by L3 and the third build-up portion 1131 is located above the third main body portion 1130, or in the first direction z, a boundary line may be defined at the portion away from the opening 11a, and the third build-up portion 1131 is located above the boundary line and the third main body portion 1130 is located below the boundary line.

[0149] In the above solution, by providing the third build-up portion 1131 in the region within 20 mm below the opening 11a of the second wall 113 in the first direction z, the strength of the portion corresponding to the opening 11a of the second wall 113 can be effectively improved, and the risk that the second wall 113 is easily cracked when receiving an impact can be reduced, and the battery cell 10 can be made highly reliable. < /

[0150] In some embodiments, the second wall 113 has a uniform thickness structure.

[0151] The statement "the second wall 113 has a uniform thickness structure" can be understood as meaning that the thickness of any part of the second wall 113 is equal in the first direction z, or it can be understood as meaning that the present application provides a battery cell 10 in which thickened areas are locally provided on the first wall 110 and corner region 112, but the second wall 113 does not have any thickened areas. Alternatively, the present application provides a battery cell 10 in which thickened areas are locally provided on the first wall 110 and corner region 112, but the entire second wall 113 is thickened.

[0152] In the above solution, under the condition that a first thickened portion 1101 is provided on the first wall 110 and a second thickened portion 1121 is provided on the corner region 112, by making the second wall 113 a uniform thickness structure, the strength of the case 11 can be guaranteed to a certain extent, the risk of the case 11 cracking can be reduced, the weight of the case 11 can be effectively controlled, and the influence on the gravimetric energy density of the battery cell 10 by making the wall thicker can be reduced.

[0153] According to some embodiments of this application, refer to Figures 4 and 12, where Figure 12 is an enlarged view of location L in Figure 4.

[0154] The battery cell 10 further includes an end cover 14 that closes the opening 11a. The third thickened portion 1131 includes a first segment 1131a and a second segment 1131b which are interconnected, and the first segment 1131a, the second segment 1131b and the third body portion 1130 (to be understood with reference to Figure 9) are distributed sequentially in the first direction z, the maximum thickness of the second segment 1131b is greater than the thickness of the third body portion 1130, and the maximum thickness of the second segment 1131b is greater than the maximum thickness of the first segment 1131a, and the end cover 14 is connected to the first segment 1131a.

[0155] In some embodiments, in the first direction z, the third reinforced section 1131 may include a multi-stage structure, for example, in the first direction z, the third reinforced section 1131 includes a first segment 1131a and a second segment 1131b that are connected to each other, with the first segment 1131a connected to the end cover 14. The method of connecting the first segment 1131a and the end cover 14 may include welding. The second segment 1131b is connected to the third main body 1130. The maximum thickness of the second segment 1131b may be the maximum thickness of the third reinforced section 1131, i.e., the maximum thickness of the second wall 113.

[0156] In some embodiments, the maximum thickness of the first segment 1131a may be less than the maximum thickness of the second segment 1131b, and may be greater than, equal to, or less than the thickness of the third main body 1130. Alternatively, the minimum thickness of the first segment 1131a may be greater than, equal to, or less than the thickness of the third main body 1130.

[0157] In the above solution, by making the thickness of the second segment 1131b of the third reinforced portion 1131 greater than the thickness of the third main body portion 1130, the strength of the second wall 113 can be effectively improved, reducing the risk of the second wall 113 cracking due to impact, and thus providing high reliability to the battery cell 10.

[0158] According to some embodiments of this application, referring to Figures 4 and 12, a first stepped surface 1131c is formed between the second segment 1131b and the first segment 1131a, and the end cover 14 is connected to overlap the first stepped surface 1131c.

[0159] In some embodiments, the maximum thickness of the second segment 1131b is greater than the maximum thickness of the first segment 1131a, so that a first stepped surface 1131c is formed between the second segment 1131b and the first segment 1131a. In some embodiments, the first stepped surface 1131c may be inclined with respect to the first direction z or perpendicular to it. The inclination of the first stepped surface 1131c with respect to the first direction z can be understood as the first stepped surface 1131c and the first direction z forming an angle that is not 90°. The phrase "the end cover 14 overlaps and connects to the first stepped surface 1131c" can be understood as the first stepped surface 1131c being able to support the end cover 14 and being able to determine the position of the end cover 14 when the end cover 14 is attached.

[0160] In the above solution, the first stepped surface 1131c formed between the second segment 1131b and the first segment 1131a allows the end cover 14 to overlap and connect to the first stepped surface 1131c, contributing to the positioning and mounting of the end cover 14. At the same time, the first stepped surface 1131c supports the end cover 14, reducing the risk of the end cover 14 falling off and further enhancing the reliability of the battery cell 10.

[0161] According to some embodiments of this application, the battery cell 10 further includes an end cover 14 that closes the opening 11a. The second thickened portion 1121 includes a third segment 1121a and a fourth segment 1121b that are interconnected, the third segment 1121a, the fourth segment 1121b and the second body portion 1120 being distributed sequentially in a first direction z, the maximum thickness of the fourth segment 1121b being greater than the thickness of the second body portion 1120, and the maximum thickness of the fourth segment 1121b being greater than the maximum thickness of the third segment 1121a, and the end cover 14 is connected to the third segment 1121a.

[0162] In some embodiments, in the first direction z, the second reinforced section 1121 may include a multi-stage structure, for example, in the first direction z, the second reinforced section 1121 includes a third segment 1121a and a fourth segment 1121b connected to each other, with the third segment 1121a connected to the end cover 14. The method of connecting the third segment 1121a and the end cover 14 may include welding. The fourth segment 1121b is connected to the second main body 1120. The maximum thickness of the fourth segment 1121b may be the maximum thickness of the second reinforced section 1121, i.e., the maximum thickness of the corner region 112.

[0163] In some embodiments, the maximum thickness of the third segment 1121a may be less than the maximum thickness of the fourth segment 1121b, and may be greater than, equal to, or less than the thickness of the second main body 1120. Alternatively, the minimum thickness of the third segment 1121a may be greater than, equal to, or less than the thickness of the second main body 1120.

[0164] In the above solution, by making the thickness of the fourth segment 1121b of the second reinforced portion 1121 greater than the thickness of the second main body portion 1120, the strength of the corner region is effectively improved, reducing the risk of stress concentration and cracking when the corner region is subjected to impact or during demolding, thereby providing high reliability to the battery cell 10.

[0165] According to some embodiments of this application, the fourth segment 1121b and the third segment 1121 a A second stepped surface 1121c is formed between the two surfaces, and the end cover 14 overlaps and connects to the second stepped surface 1121c.

[0166] In some embodiments, the maximum thickness of the fourth segment 1121b is equal to that of the third segment 1121 a Because it is greater than the maximum thickness of the fourth segment 1121b and the third segment 1121 aA second stepped surface 1121c is formed between the two surfaces. In some embodiments, the second stepped surface 1121c may be inclined with respect to the first direction z, or it may be perpendicular to it. The inclination of the second stepped surface 1121c with respect to the first direction z can be understood as forming an angle that is not 90° between the second stepped surface 1121c and the first direction z.

[0167] The phrase "the end cover 14 is connected to the second stepped surface 1121c by overlapping it" can be understood as meaning that the second stepped surface 1121c can support the end cover 14, and that when the end cover 14 is installed, the second stepped surface 1121c can determine the position of the end cover 14.

[0168] In the above solution, the fourth segment 1121b and the third segment 1121 a The second stepped surface 1121c formed between the two surfaces allows the end cover 14 to overlap and connect to the second stepped surface 1121c, contributing to the positioning and mounting of the end cover 14. At the same time, the second stepped surface 1121c supports the end cover 14, reducing the risk of the end cover 14 falling off and further enhancing the reliability of the battery cell 10.

[0169] For some embodiments of this application, please refer to Figure 13, which is a schematic diagram of the end cover and corner area in some embodiments of this application.

[0170] The battery cell 10 further includes an end cover 14 welded to the second thickened portion 1121 to form a welded region 114, wherein the average crystal grain size of the portion of the second thickened portion 1121 other than the welded region 114 is larger than the average crystal grain size of the second main body portion 1120, and the average crystal grain size is the average crystal grain size in the first direction z of the crystal grains.

[0171] The welding region 114 is the region formed by welding the second thickened portion 1121 and the end cover 14, and in some embodiments, the welding region 114 may also be called the welding area or welding mark.

[0172] "The portion of the second reinforced section 1121 other than the welding area 114" can be understood as the portion of the second reinforced section that is not connected to the end cover 14, that is, the portion of the second reinforced section 1121 that is not the welding area 114.

[0173] In some examples, GB / T 6394-2017 "Method for Measuring Average Crystal Grain Size of Metals" and GB / T 13298-2017 "Electron Backmicroscopy Method for Measuring Crystal Grain Size of Metallic Materials" are used as standards for measuring the average crystal grain size.

[0174] In the above solution, by limiting the average crystal grain size of the portion of the second reinforced portion 1121 other than the welding area 114 to be larger than the average crystal grain size of the second main body portion 1120, it is possible to increase the strength of the second reinforced portion 1121, giving the corner region 112 high strength, reducing the risk of the corner region 112 cracking near the welding area 114 due to impact, and the risk of the corner region 112 cracking due to stress concentration during demolding, thereby providing high reliability to the battery cell 10.

[0175] In another embodiment, the end cover 14 and the first thickened portion 1101 are welded together to form a welded area, and the average crystal grain size of the portion of the first thickened portion 1101 outside the welded area is larger than the average crystal grain size of the first main body portion 1100, and the average crystal grain size is the average crystal grain size in the first direction z of the crystal grains. In another embodiment, the end cover 14 and the third thickened portion 1131 are welded together to form a welded area, and the average crystal grain size of the portion of the third thickened portion 1131 outside the welded area is larger than the average crystal grain size of the third main body portion 1130, and the average crystal grain size is the average crystal grain size in the first direction z of the crystal grains.

[0176] According to some embodiments of this application, in a cross-section parallel to the first direction z of the corner region 112, the portion of the second thickened portion 1121 located below the welded region 114 has 15 or more crystal grains in the width direction of the cross-section.

[0177] In some embodiments, the "width direction of the cross-section" may be the thickness direction of the corner region 112.

[0178] In some embodiments, the statement "the portion of the second thickened portion 1121 located below the welding area 114 has 15 or more crystalline grains in the width direction of the cross-section" may be understood as meaning that, for the portion of the second thickened portion 1121 between the welding area 114 and the second main body portion 1120, the number of crystalline grains in the thickness direction of the corner region 112 may be 15, 16, 17, or more.

[0179] In the above solution, since the number of crystal grains in the width direction of the cross-section is 15 or more, it contributes to increasing the strength of the second thickened portion 1121 and improving the reliability of the battery 100.

[0180] In another embodiment, in a cross-section of the first wall 110 parallel to the first direction z, the portion of the first thickened portion 1101 located below the welding area 114 has 15 or more crystal grains in the width direction of the cross-section. In another embodiment, in a cross-section of the second wall 113 parallel to the first direction z, the portion of the third thickened portion 1131 located below the welding area 114 has 15 or more crystal grains in the width direction of the cross-section.

[0181] According to some embodiments of this application, the average crystal grain size range of the portion of the second thickened portion 1121 other than the welded area 114 is 70 micrometers to 1200 micrometers.

[0182] And / or, in some embodiments, the average crystal grain size range of the second main body 1120 is 30 micrometers to 1000 micrometers. And / or, in some embodiments, the maximum wall thickness of the end cover 14 is 0.25 mm to 3 mm.

[0183] In some embodiments, the average crystal grain size of the portion of the second thickened portion 1121 other than the welded area 114 may be 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, etc., or any value between adjacent values, but is not limited to these.

[0184] In some embodiments, the average crystal grain size of the second main body 1120 may be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc., or any value between adjacent values, but is not limited to these.

[0185] In some examples, the method for measuring the average crystal grain size can be found in GB / T 6394-2002 "Method for Measuring Crystal Grain Size of Metallic Materials" and GB / T 13298-2017 "Electron Back Microscopy Method for Measuring Crystal Grain Size of Metallic Materials".

[0186] In some embodiments, the maximum wall thickness of the end cover 14 may be 0.25 mm, 0.35 mm, 0.45 mm, 0.55 mm, 0.65 mm, 0.75 mm, 0.85 mm...2.75 mm, 2.85 mm, 2.95 mm, 3 mm, etc., or any value between adjacent values, but is not limited to these.

[0187] In the above solution, the average crystal particle size of the second reinforced portion 1121 and / or the average crystal particle size of the second main body portion 1120 satisfy the above relationship, thereby contributing to an increase in the strength of the second reinforced portion 1121 and providing high reliability to the battery cell 10.

[0188] According to some embodiments of this application, the present application further provides a battery 100 including the battery cell 10 described above.

[0189] In some embodiments, the battery 100 comprises a battery cell 10 and a box 20 that houses the battery cell 10. Here, the box 20 provides a housing space for the battery cell 10. In the battery 100, there may be one or more battery cells 10, and each battery cell 10 can be fixed to the box 20 via a connecting member (e.g., a bolt), or by adhesive.

[0190] According to some embodiments of this application, the present application further provides an energy storage device including the battery cell 10 described above.

[0191] The energy storage device may include an energy storage cabinet, which includes a cabinet and one or more battery cells 10 or one or more batteries 100 provided in the cabinet. The cabinet may include a cabinet body and a cabinet door, with one or more battery cells 10 provided in the cabinet body, and the cabinet door closes the opening 11a of the cabinet body, thereby positioning one or more battery cells 10 in a closed space and reducing the interference effect of external materials on the battery cells 10.

[0192] According to some embodiments of this application, the present application further provides an electrical device including the battery cell 10 described above.

[0193] In some embodiments, the electrical device may be a vehicle. A controller, a motor, and a battery cell 10 may be provided inside the vehicle, and the controller is used to control the power supply of the battery cell 10 to the motor.

[0194] Refer to Figures 4-11 for some embodiments of this application. A battery cell 10 is provided, including a case 11 and an end cover, wherein in a first direction z, the case 11 has an opening 11a, an electrode assembly 12 is provided inside the case 11, and the end cover is connected to the case 11 and closes the opening 11a, thereby positioning the electrode assembly 12 in a closed space. The case 11 includes two opposing first walls 110 in a second direction x, and two opposing second walls 113 in a third direction y, with the second direction x and the third direction y being perpendicular to each other with respect to the first direction z. Adjacent first walls 110 and second walls 113 are connected via corresponding corner regions 112, and the first walls 110, second walls 113 and corner regions 112 together enclose an opening 11a.

[0195] The first wall 110 comprises a first main body portion 1100 and a first reinforced portion 1101 arranged in a first direction z, wherein the first main body portion 1100 is further away from the opening 11a than the first reinforced portion 1101, and the maximum thickness of the first reinforced portion 1101 is greater than the thickness of the first main body portion 1100. The second wall 113 comprises a third main body portion 1130 and a third reinforced portion 1131 arranged in a first direction z, wherein the third main body portion 1130 is further away from the opening 11a than the third reinforced portion 1131, and the maximum thickness of the third reinforced portion 1131 is greater than the thickness of the third main body portion 1130.

[0196] Here, the corner region 112 comprises a second main body portion 1120 and a second thickening portion 1121 arranged in a first direction z, wherein the second main body portion 1120 is further away from the opening 11a than the second thickening portion 1121, and the maximum thickness of the second thickening portion 1121 is greater than the thickness of the second main body portion 1120.

[0197] In the above solution, by providing a first thickening portion 1101 on the first wall 110 and a third thickening portion 1131 on the second wall 113, a heat-affected zone with low strength due to welding is formed in the case 11. Therefore, when the case 11 is subjected to an impact, the problem of cracking with insufficient strength can be improved, and the battery 100 can be given high reliability. At the same time, by providing a second thickening portion 1121 in the corner region 112, the strength of the portion corresponding to the opening 11a in the corner region 112 is increased, and the problem of cracking in the corner region 112 due to stress concentration during mold release caused by the installation of the first thickening portion 1101 and the second thickening portion 1121 can be improved, and the battery cell 10 can be given high reliability.

[0198] In some embodiments, when the thickness of the second thickening portion 1121 is T1 and the thickness of the second main body portion 1120 is T2, 0 < E < 30% is satisfied, and E = (T1 - T2) / T2. In another embodiment, 0 < E ≤ 16.7%.

[0199] As an example, based on the battery cell 10 provided above, test verification is performed for different E values and mold release feasibility, and the test verification results can be referred to the following table.

[0200] JPEG2026516440000016.jpg21157

[0201] As can be seen from the above table, the degree of thickening of the thickening portion in the corner region 112 can take a certain range. For example, when the thickness of the second thickening portion 1121 is T1 and the thickness of the second main body portion 1120 is T2, 0 < E < 30% is satisfied.

[0202] The above are only preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and principle of the present application are all included within the scope of the claims of the present application.

Description of Reference Numerals

[0203] 100 Battery 10 battery cells 11 cases 12 Electrode assembly 13 Electrode terminal 11a opening 14 End cover 110 1st wall 1100 First main body 1101 1st thickening section 112 Corner Area 1120 Second main body 1121 2nd thickening section 1121a Third segment 1121b Segment 4 1121c 2nd step surface 113 Second wall 1130 Third Main Body 1131 3rd thickening section 1131a First segment 1131b Second segment 1131c 1st step surface 114 Welding Area 20 boxes 21. First Box Section 22 Second Box Section z 1st direction x 2nd direction y Third direction 1000 vehicles 200 controllers 300 motor 2000 Energy storage devices 2001 Cabinet

Claims

1. The case includes an opening formed at the end along a first direction, and a first wall, a corner region, and a second wall connected in order in the circumferential direction of the opening. The first wall comprises a first main body portion and a first reinforced portion arranged in the first direction, the first main body portion being further away from the opening than the first reinforced portion, and the first reinforced portion having a maximum thickness greater than the thickness of the first main body portion. The battery cell wherein the corner region comprises a second main body portion and a second thickening portion arranged in the first direction, the second main body portion being further away from the opening than the second thickening portion, and the second thickening portion having a maximum thickness greater than the thickness of the second main body portion.

2. The battery cell according to claim 1, wherein the maximum thickness of the second thickened portion is greater than the maximum thickness of the first thickened portion.

3. The battery cell according to claim 1 or claim 2, wherein the maximum thickness of the second reinforced portion is T1, the thickness of the second main body is T2, the maximum thickness of the first reinforced portion is t1, and the thickness of the first main body is t2, such that E ≥ F, and E = (T1 - T2) / T2, F = (t1 - t2) / t2.

4. The battery cell according to any one of claims 1 to 3, wherein the maximum thickness of the second thickened portion is T1 and the thickness of the second main body is T2, such that 0 < E < 30% and E = (T1 - T2) / T2.

5. A battery cell according to claim 4, satisfying 0 < E ≤ 16.7%.

6. In the first direction, if L1 is the distance from one end of the second thickened portion away from the opening to the opening, then the battery cell according to any one of claims 1 to 5 satisfies 0 < L1 ≤ 20 mm.

7. In the first direction, if L2 is the distance from one end of the first thickened portion away from the opening to the opening, then the battery cell according to any one of claims 1 to 6 satisfies 0 < L2 ≤ 20 mm.

8. The battery cell according to any one of claims 1 to 7, wherein the area of ​​the outer surface of the first wall is greater than the area of ​​the outer surface of the second wall.

9. The case includes two opposing first walls in a second direction, and two opposing second walls in a third direction, wherein the second and third directions are mutually perpendicular to the first direction. The battery cell according to any one of claims 1 to 8, wherein the adjacent first wall and the second wall are connected via the corresponding corner region, and the first wall, the second wall and the corner region together enclose and form the opening.

10. The battery cell according to any one of claims 1 to 9, wherein the second wall comprises a third main body portion and a third thickening portion arranged in the first direction, the third main body portion is further away from the opening than the third thickening portion, and the maximum thickness of the third thickening portion is greater than the thickness of the third main body portion.

11. The battery cell according to claim 10, wherein the maximum thickness of the second thickened portion is greater than the maximum thickness of the third thickened portion.

12. The battery cell according to claim 10 or claim 11, wherein the maximum thickness of the second reinforced portion is T1, the thickness of the second main body is T2, the maximum thickness of the third reinforced portion is t3, and the thickness of the third main body is t4, such that E ≥ G, and E = (T1 - T2) / T2, G = (t3 - t4) / t4.

13. In the first direction, if L3 is the distance from one end of the third thickened portion away from the opening to the opening, then the battery cell according to any one of claims 10 to 12 satisfies 0 < L3 ≤ 20 mm.

14. The present invention further includes an end cover that closes the aforementioned opening, The battery cell according to any one of claims 10 to 13, wherein the third thickened portion includes a first segment and a second segment connected to each other, the first segment, the second segment and the third main body are distributed sequentially in the first direction, the maximum thickness of the second segment is greater than the thickness of the third main body, the maximum thickness of the second segment is greater than the maximum thickness of the first segment, and the end cover is connected to the first segment.

15. The battery cell according to claim 14, wherein a first stepped surface is formed between the second segment and the first segment, and the end cover is connected to overlap the first stepped surface.

16. The present invention further includes an end cover that closes the aforementioned opening, The battery cell according to any one of claims 1 to 15, wherein the second thickened portion includes a third segment and a fourth segment connected to each other, the third segment, the fourth segment and the second main body are distributed sequentially in the first direction, the maximum thickness of the fourth segment is greater than the thickness of the second main body, the maximum thickness of the fourth segment is greater than the maximum thickness of the third segment, and the end cover is connected to the third segment.

17. The battery cell according to claim 16, wherein a second stepped surface is formed between the fourth segment and the third segment, and the end cover is connected to overlap the second stepped surface.

18. The battery cell according to any one of claims 1 to 17, further comprising an end cover welded to the second thickened portion to form a welded area, wherein the average crystal particle size of the portion of the second thickened portion other than the welded area is larger than the average crystal particle size of the second main body, and the average crystal particle size is the average crystal particle size of the crystal particles in a first direction.

19. The battery cell according to claim 18, wherein in a cross section parallel to the first direction of the corner region, the portion of the second thickened portion located below the welded region has 15 or more crystalline grains in the width direction of the cross section.

20. The average crystal grain size range of the portion of the second thickened section other than the welded area is 70 micrometers to 1200 micrometers. and / or, the average crystal grain size range of the second main body is 30 micrometers to 1000 micrometers. and / or the battery cell according to claim 18 or claim 19, wherein the maximum wall thickness of the end cover is 0.25 mm to 3 mm.

21. A battery comprising a battery cell according to any one of claims 1 to 20.

22. An energy storage device comprising a battery cell according to any one of claims 1 to 20.

23. An electrical device comprising a battery cell according to any one of claims 1 to 20.

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