Battery cell, battery, electrical device and energy storage device

Abstract

A battery cell (20), a battery (100), an electrical device and an energy storage device. The battery cell (20) comprises a housing (21), wherein the housing (21) comprises a casing (211) and an end cover (212), the casing (211) being provided with an opening (213), and comprising a first wall (30), the first wall (30) comprising a first opening portion (31) and a first body portion (32) which are distributed in sequence in a first direction, the first body portion (32) being further away from the opening (213) than the first opening portion (31), and the end cover (212) being welded to the first opening portion (31) so as to close the opening (213). The first opening portion (31) comprises a plurality of first thickened regions (311) and at least one first transition region (312), wherein the plurality of first thickened regions (311) are arranged spaced apart from each other in the first direction, two adjacent first thickened regions (311) are connected by means of the first transition region (312), the maximum thickness of the first thickened region (311) is greater than the thickness of the first body portion (32), the maximum thickness of the first transition region (312) is greater than or equal to the thickness of the first body portion (32), and the maximum thickness of the first thickened region (311) is greater than the maximum thickness of the first transition region (312), such that the reliability of the battery cell (20) can be improved.

Description

Battery cells, batteries, electrical equipment and energy storage devices CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application CN2024202923585, entitled “Battery Cell, Battery, Electrical Equipment and Energy Storage Device”, filed on February 18, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, an electrical device, and an energy storage device. Background Art

[0003] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0004] During the manufacturing process of batteries, battery reliability is an issue that cannot be ignored. Therefore, how to improve battery reliability is a technical problem that needs to be solved urgently in battery technology. Summary of the Invention

[0005] The present application provides a battery cell, a battery, an electrical device and an energy storage device, which can improve the reliability of the battery cell.

[0006] This application is achieved through the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a battery cell, which includes a shell. The shell includes a shell and an end cover. The shell has an opening. The shell includes a first wall. The first wall includes a first opening portion and a first main body portion distributed in sequence along a first direction. The first direction is parallel to the thickness direction of the end cover. The first main body portion is away from the opening relative to the first opening portion. The end cover is welded to the first opening portion to close the opening. The first opening portion includes a plurality of first thickened regions and at least one first transition region. The plurality of first thickened regions are spaced apart along the first direction. Two adjacent first thickened regions are connected by the first transition region. The maximum thickness of the first thickened region is greater than the thickness of the first main body portion. The maximum thickness of the first transition region is greater than or equal to the thickness of the first main body portion. The maximum thickness of the first thickened region is greater than the maximum thickness of the first transition region.

[0008] In a battery cell according to an embodiment of the present application, the first opening portion includes multiple first thickened regions spaced apart along a first direction. The maximum thickness of the first thickened regions is greater than the thickness of the first main body portion. The thickening of the first thickened regions relative to the first main body portion enhances the strength of the first opening portion, reducing the risk of cracking in the area near the weld between the housing and the end cap, thereby enhancing the battery cell's service life and reliability. Furthermore, the multiple first thickened regions spaced apart along the first direction facilitate the expansion of the material during the stamping and forming of the housing, reducing the difficulty of manufacturing the battery cell.

[0009] According to some embodiments of the present application, the difference between the maximum thickness of the first thickened area and the thickness of the first main body is greater than or equal to 0.05 mm, and the difference between the maximum thickness of the first thickened area and the thickness of the first main body is less than or equal to the thickness of the first main body.

[0010] In the above scheme, the difference between the maximum thickness of the first thickened area and the thickness of the first main body satisfies the above relationship. On the one hand, when the difference between the maximum thickness of the first thickened area and the thickness of the first main body is greater than or equal to 0.05 mm, the first thickened area has a higher strength, so that the first opening has a higher strength; on the other hand, when the difference between the maximum thickness of the first thickened area and the thickness of the first main body is less than or equal to the thickness of the first main body, the space occupied by the first thickened area is smaller, so that the battery cell has a higher energy density.

[0011] According to some embodiments of the present application, the maximum thickness of the first thickened area is greater than or equal to 0.25 mm, and the maximum thickness of the first thickened area is less than or equal to 2.4 mm.

[0012] In the above scheme, the maximum thickness of the first thickened area satisfies the above relationship. On the one hand, when the maximum thickness of the first thickened area is greater than or equal to 0.25 mm, the first thickened area has higher strength. On the other hand, when the maximum thickness of the first thickened area is less than or equal to 2.4 mm, the first thickened area occupies less space in the thickness direction of the first wall, and has less impact on the energy density of the battery cell.

[0013] According to some embodiments of the present application, along the first direction, the distance between two adjacent first thickened areas is greater than or equal to 2 mm, and the distance between two adjacent first thickened areas is less than or equal to 15 mm.

[0014] In the above scheme, the distance between two adjacent first thickened areas satisfies the above relationship. On the one hand, when the distance between two adjacent first thickened areas is less than or equal to 15 mm, multiple first thickened areas have a larger size in the first direction, which can improve the strength of the first opening. On the other hand, when the distance between two adjacent first thickened areas is greater than or equal to 2 mm, it can facilitate the extension of the material during the stamping of the shell and reduce the difficulty of processing and manufacturing.

[0015] According to some embodiments of the present application, the number of the first thickened regions is 2 or 3.

[0016] In the above solution, the number of first thickened areas is 2 or 3. While making the first opening portion have higher strength, the size occupied by multiple first thickened areas in the first direction can be smaller, reducing the risk of interference between the first thickened areas and other components.

[0017] According to some embodiments of the present application, multiple first thickening regions include a first sub-thickening region and a second sub-thickening region, the first sub-thickening region and the second sub-thickening region are spaced apart along the first direction, the first sub-thickening region is closer to the opening than the second sub-thickening region, the end cover is welded to the first sub-thickening region, and along the first direction, the maximum thickness of the first sub-thickening region is equal to the maximum thickness of the second sub-thickening region, and the thickness of the second sub-thickening region gradually decreases from an end close to the first sub-thickening region toward an end away from the first sub-thickening region.

[0018] In the above solution, the first sub-thickened area and the second sub-thickened area are spaced apart along the first direction, so that the first opening has higher strength, which can reduce the risk of the shell cracking near the connection position between the shell and the end cover.

[0019] According to some embodiments of the present application, multiple first thickened regions include a first sub-thickened region closest to the opening, and the end cover is welded to the first sub-thickened region; wherein, along the first direction, the difference between the size of the first sub-thickened region and the thickness of the end cover is greater than or equal to 0, and the difference between the size of the first sub-thickened region and the thickness of the end cover is less than or equal to 2 times the thickness of the end cover.

[0020] In the above scheme, the end cover is connected to the first sub-thickening area, and the difference between the size of the first thickening area in the first direction and the thickness of the end cover satisfies the above relationship. On the one hand, when the difference between the size of the first sub-thickening area and the thickness of the end cover is greater than or equal to 0, the connection between the end cover and the shell is stable, and the risk of cracking of the shell in the area near the welding position of the shell and the end cover is reduced; on the other hand, when the difference between the size of the first sub-thickening area and the thickness of the end cover is less than or equal to 2 times the thickness of the end cover, the space occupied by multiple first thickening areas in the first direction is small, reducing the risk of interference between multiple first thickening areas and other components.

[0021] According to some embodiments of the present application, there are two first walls, and the two first walls are arranged opposite to each other in the second direction; the shell also includes two second walls arranged opposite to each other in the third direction, the two first walls and the two second walls form an opening, the first direction, the second direction and the third direction are perpendicular to each other, and the area of ​​the outer surface of the first wall is greater than the area of ​​the outer surface of the second wall.

[0022] In the above solution, the first wall can be the large surface of the shell. Providing the first thickened area can enhance the strength of the first wall and reduce the risk of cracking of the shell near the welding position of the shell and the end cover.

[0023] According to some embodiments of the present application, the second wall includes a second opening portion and a second main body portion distributed in sequence along the first direction, the second opening portion is close to the opening relative to the second main body portion, the second opening portion includes a plurality of second thickening areas and at least one second transition area, the plurality of second thickening areas are spaced apart along the first direction, two adjacent second thickening areas are connected by the second transition area, the plurality of second thickening areas include a third sub-thickening area and at least one fourth sub-thickening area, the third sub-thickening area is closest to the opening, the end cover is welded to the third sub-thickening area, the difference between the maximum thickness of the third sub-thickening area and the thickness of the second main body portion is greater than 0.2 mm, the maximum thickness of the fourth sub-thickening area is greater than the thickness of the second main body portion, the maximum thickness of the fourth sub-thickening area is greater than the maximum thickness of the second transition area, and the maximum thickness of the second transition area is greater than or equal to the thickness of the second main body portion.

[0024] In the above scheme, the second wall is the side of the shell, the third sub-thickening area is closest to the opening, the third sub-thickening area is connected to the end cover, the maximum thickness of the third sub-thickening area, the maximum thickness of the fourth sub-thickening area, and the thickness of the second transition area satisfy the above relationship, so that the second wall is firmly connected to the end cover, and the second opening has higher strength, reducing the risk of cracking of the shell in the area near the welding position of the shell and the end cover; at the same time, multiple third thickening areas are arranged at intervals along the first direction, which can facilitate the extension of the material during stamping and forming of the shell, reducing the difficulty of manufacturing the battery cell.

[0025] According to some embodiments of the present application, at least one second transition zone includes a first sub-transition zone connected to a third sub-thickening zone, the maximum thickness of the first sub-transition zone is greater than the maximum thickness of the third sub-thickening zone, a first step surface is formed between the first sub-transition zone and the third sub-thickening zone, and the end cover overlaps the first step surface.

[0026] In the above scheme, the maximum thickness of the first sub-transition zone is greater than the maximum thickness of the third sub-thickening zone, so that the second opening portion has higher strength, reducing the risk of cracking in the area near the welding position of the shell and the end cover. The setting of the first step surface facilitates the positioning of the end cover and the assembly of the end cover and the shell.

[0027] According to some embodiments of the present application, the end cover has a first surface facing away from the interior of the battery cell, and along the first direction, the maximum distance between one end of the plurality of first thickened regions facing away from the first surface and the first surface is less than or equal to 10 mm.

[0028] In the above scheme, along the first direction, the maximum distance between the end of the multiple first thickened areas facing away from the first surface and the first surface is less than or equal to 10 mm, which not only makes the first opening portion have higher strength to reduce the risk of cracking of the shell near the welding position of the shell and the end cover, but also facilitates the demolding of the shell during the processing and manufacturing process, thereby facilitating processing and manufacturing.

[0029] According to some embodiments of the present application, the number of first walls is two, and the two first walls are arranged opposite to each other in the second direction; the shell also includes a bottom wall and two second walls arranged opposite to each other in the third direction, the two first walls and the two second walls form an opening, and along the first direction, the bottom wall and the opening are arranged opposite to each other, and the first direction, the second direction and the third direction are perpendicular to each other.

[0030] In the above solution, the bottom wall is arranged opposite to the opening. During the assembly of the battery cell, the bottom wall can support the electrode assembly to facilitate positioning of the electrode assembly.

[0031] According to some embodiments of the present application, the shell is a prismatic structure with openings at both ends, and there are two end covers, which respectively close the two openings.

[0032] In the above solution, the shell has two openings, and the two end covers respectively close the two openings to facilitate assembly of the electrode assembly and the shell.

[0033] In a second aspect, an embodiment of the present application further provides a battery, which includes a battery cell provided in any of the above embodiments.

[0034] According to some embodiments of the present application, there are multiple battery cells, and the multiple battery cells are stacked along the second direction to form a battery cell group. The second direction is parallel to the thickness direction of the first wall. The battery also includes an end plate. Along the second direction, the end plate is arranged at the end of the battery cell group, along the direction of the first main body portion pointing to the first opening portion, and at least a portion of the first opening portion exceeds the end plate.

[0035] In the above solution, the end plate is arranged at the end of the battery cell group in the third direction, and the end plate has a large connection area with the shell of the adjacent battery cell to form a constraint on the shell, thereby reducing the risk of cracking of the shell in the area near the welding position of the shell and the end cover.

[0036] In a third aspect, an embodiment of the present application further provides an electrical device, which includes a battery cell or battery as provided in any of the above embodiments, and the battery cell or battery is used to provide electrical energy.

[0037] In a fourth aspect, an embodiment of the present application further provides an energy storage device, which includes a battery cell or a battery as provided in any of the above embodiments.

[0038] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0040] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0041] FIG2 is an exploded schematic diagram of a battery provided in some embodiments of the present application;

[0042] FIG3 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0043] FIG4 is a cross-sectional view of a battery cell provided in some embodiments of the present application;

[0044] FIG5 is a partial enlarged view of point A in FIG4 ;

[0045] FIG6 is a schematic structural diagram of a first wall of a housing provided in some embodiments of the present application;

[0046] FIG7 is a schematic diagram of the assembly of the end cover and the second wall provided in some embodiments of the present application;

[0047] FIG8 is a schematic structural diagram of a second wall provided in some embodiments of the present application;

[0048] FIG9 is a schematic diagram of the assembly of an end plate and a battery cell group according to some embodiments of the present application;

[0049] FIG10 is a schematic diagram of the assembly of an end plate and a battery cell according to some embodiments of the present application;

[0050] FIG11 is a partial enlarged view of point B in FIG10 .

[0051] In the drawings, the drawings are not drawn to scale.

[0052] Marking instructions: 100 - battery; 10 - housing; 11 - first sub-housing; 12 - second sub-housing; 20 - battery cell; 20a - battery cell group; 21 - housing; 211 - casing; 212 - end cover; 212a - first surface; 213 - opening; 214 - first welding area; 215 - second welding area; 216 - bottom wall; 22 - electrode assembly; 23 - electrode terminal; 30 - first wall; 31 - first opening; 311 - first thickened area; 311a - first sub-thickened area; 311b-second sub-thickening area; 312-first transition area; 32-first main body; 40-second wall; 41-second opening; 411-second thickening area; 411a-third sub-thickening area; 411b-fourth sub-thickening area; 412-second transition area; 412a-first sub-transition area; 413-first step surface; 42-second main body; 50-end plate; 200-controller; 300-motor; 1000-vehicle; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0053] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0055] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0056] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0057] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0058] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0059] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0060] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0061] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0062] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0063] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0064] The battery cells may be, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0065] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0066] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0067] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

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

[0069] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.

[0070] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0071] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium.

[0072] In some embodiments, the negative electrode current collector has two opposite surfaces in its thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0073] As an example, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0074] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0075] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0076] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0077] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0078] In some embodiments, the electrode assembly is a laminate structure.

[0079] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, or a composite metal housing (e.g., a copper-aluminum composite housing).

[0080] In some embodiments, the housing includes an end cap and a shell. The shell has an opening, and the end cap closes the opening to form a sealed space for accommodating the electrode assembly, electrolyte, and other substances. The shell may have one or more openings. One or more end caps may also be provided.

[0081] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to a tab of the electrode assembly. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal may be provided on an end cap or on the housing.

[0082] In some embodiments, the housing is provided with an explosion-proof valve for releasing the internal pressure of the battery cell.

[0083] As an example, the battery cell may be a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery.

[0084] The development of battery technology must take into account multiple design factors at the same time, such as energy density, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery reliability must also be considered.

[0085] In some embodiments, a battery cell includes an outer shell and an electrode assembly, wherein the electrode assembly is disposed within the outer shell. The outer shell includes a housing and an end cap, wherein the housing has an opening and the end cap closes the opening. The end cap is typically welded to the housing. Due to the high temperature during welding of the end cap and the housing, a heat-affected zone is formed in the area near the welding position of the end cap and the housing, and the strength of the portion in the heat-affected zone is reduced. During the charge and discharge cycle of the battery cell, or when the electrode assembly produces a large amount of gas, or when the battery cell experiences thermal runaway, the housing may easily crack in the area near the welding position of the housing and the end cap, causing damage to the housing and reducing the service life and reliability of the battery cell.

[0086] In view of this, an embodiment of the present application provides a technical solution, wherein a battery cell includes a shell, the shell includes a shell and an end cap, the shell has an opening, the shell includes a first wall, the first wall includes a first opening portion and a first main portion distributed in sequence along a first direction, the first direction is parallel to the thickness direction of the end cap, the first main portion is away from the opening relative to the first opening portion, and the end cap is welded to the first opening portion to close the opening. The first opening portion includes a plurality of first thickened regions, the plurality of first thickened regions are spaced apart along the first direction, any two adjacent first thickened regions are connected by a first transition region, the maximum thickness of the first thickened region is greater than the thickness of the first main portion, the thickness of the first transition region is greater than or equal to the thickness of the first main portion, and the maximum thickness of the first thickened region is greater than the maximum thickness of the first transition region, so that the first opening portion has a higher strength, can reduce the risk of cracking of the shell in the area near the welding position of the shell and the end cap, and improve the service life and reliability of the battery cell.

[0087] In such a battery cell, the first thickened region is thickened relative to the first main body, resulting in higher strength. This enhances the strength of the first opening, improves the connection stability between the end cap and the first wall, and reduces the risk of cracking in the area near the weld between the housing and the end cap, resulting in a longer battery cell lifespan and higher reliability. Furthermore, the multiple first thickened regions are spaced apart along the first direction, facilitating material expansion during stamping and forming of the housing, reducing the manufacturing difficulty of the battery cell.

[0088] The battery disclosed in the embodiments of the present application can be used, but is not limited to, in electrical equipment such as vehicles, ships, or aircraft. The battery disclosed in the present application can be used to form a power supply system for the electrical equipment.

[0089] The embodiments of the present application provide an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0090] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0091] Please refer to Figure 1, which is a schematic diagram of the structure of the vehicle provided in some embodiments of the present application. Vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source for the vehicle 1000, for the circuit system of the vehicle 1000, such as for the working power requirements during the startup, navigation and operation of the vehicle 1000.

[0092] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0093] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0094] Please refer to Figure 2, which is an exploded schematic diagram of a battery provided in some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 being housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20, and the housing 10 can adopt a variety of structures. In some embodiments, the housing 10 can include a first sub-housing 11 and a second sub-housing 12, the first sub-housing 11 and the second sub-housing 12 covering each other, and the first sub-housing 11 and the second sub-housing 12 jointly defining a storage space for accommodating the battery cell 20. The second sub-housing 12 can be a hollow structure with one end open, and the first sub-housing 11 can be a plate-shaped structure, with the first sub-housing 11 covering the open side of the second sub-housing 12, so that the first sub-housing 11 and the second sub-housing 12 jointly define a storage space; the first sub-housing 11 and the second sub-housing 12 can also be hollow structures with one end open, with the open side of the first sub-housing 11 covering the open side of the second sub-housing 12.

[0095] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0096] The battery cell 20 may be a secondary battery or a primary battery; the battery cell 20 may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0097] Please refer to Figure 3, which is an exploded schematic diagram of a battery cell provided in some embodiments of the present application. As shown in Figure 3, a battery cell 20 includes a housing 21, an electrode assembly 22, and other functional components. Housing 21 includes a shell 211 and an end cap 212. Shell 211 has an opening, and end cap 212 closes the opening, isolating the internal environment of battery cell 20 from the external environment.

[0098] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. The housing 211 can be of various shapes and sizes. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The housing 211 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0099] The end cap 212 is a component that covers the opening of the housing 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 212 can be adapted to the shape of the housing 211 to match the housing 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the end cap 212 from deforming when subjected to compression or collision, giving the battery cell 20 greater structural strength and improved reliability. Functional components such as electrode terminals 23 can be provided on the end cap 212. The electrode terminals can be used to electrically connect to the electrode assembly 22 to output or input electrical energy to the battery cell 20. The end cap 212 can also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this is not particularly limited in the embodiments of the present application. In some embodiments, an insulating structure can be provided on the inner side of the end cap 212 to isolate the electrical connection components within the housing 211 from the end cap 212 to reduce the risk of short circuits. For example, the insulating structure may be plastic, rubber, or the like.

[0100] The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 22 may be contained in the housing 211. The electrode assembly 22 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The separator is used to separate the positive electrode sheet and the negative electrode sheet to avoid internal short circuits between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive electrode tab and the negative electrode tab may be located together at one end of the main body or respectively at both ends of the main body.

[0101] Please refer to Figures 4 to 6. Figure 4 is a cross-sectional view of a battery cell provided in some embodiments of the present application. Figure 5 is a partial enlarged view of point A in Figure 4. Figure 6 is a schematic structural diagram of the first wall of the shell provided in some embodiments of the present application, wherein Figure 6 is a schematic structural diagram of the first wall before the end cover and the shell are assembled. According to some embodiments of the present application, the present application provides a battery cell 20, which includes a shell 21. The shell 21 includes a shell 211 and an end cover 212. The shell 211 has an opening 213. The shell 211 includes a first wall 30. The first wall 30 includes a first opening portion 31 and a first body portion 32 distributed in sequence along a first direction X. The first direction X is parallel to the thickness direction of the end cover 212. The first body portion 32 is away from the opening 213 relative to the first opening portion 31. The end cover 212 is welded to the first opening portion 31 to close the opening 213. In which, the first opening portion 31 includes multiple first thickened areas 311 and at least one first transition area 312, multiple first thickened areas 311 are arranged at intervals along the first direction X, and two adjacent first thickened areas 311 are connected by the first transition area 312. The maximum thickness of the first thickened area 311 is greater than the thickness of the first main body portion 32, the maximum thickness of the first transition area 312 is greater than or equal to the thickness of the first main body portion 32, and the maximum thickness of the first thickened area 311 is greater than the maximum thickness of the first transition area 312.

[0102] In the figure, the direction indicated by the letter X may be the first direction. The direction indicated by the letter Y may be parallel to the thickness direction of the first wall 30. The thickness direction of the first wall 30 may be parallel to the width direction of the battery cell 20, or the thickness direction of the first wall 30 may be parallel to the length direction of the battery cell 20.

[0103] The end cover 212 is disposed in the opening 213 . The end cover 212 has a side surface facing the inner surface of the shell 211 . The side surface is connected to the inner surface of the shell 211 to facilitate welding of the end cover 212 and the shell 211 .

[0104] Along the first direction X, the first opening portion 31 and the first body portion 32 are distributed in sequence, and the first opening portion 31 forms an opening 213 for connecting with the end cover 212 .

[0105] Two adjacent first thickened areas 311 are connected by the first transition area 312, so that the first transition area 312 separates the two adjacent first thickened areas 311, and the first thickened areas 311 and the first transition areas 312 are staggered in the first direction X to facilitate the extension of the material when the shell 211 is stamped.

[0106] In some embodiments, the first thickened region 311 may have a variable thickness structure or a uniform thickness structure. When the first thickened region 311 has a variable thickness structure, the maximum thickness of the first thickened region 311 is the thickness at the location where the thickness of the first thickened region 311 is the maximum. When the first thickened region 311 has a uniform thickness structure, the maximum thickness of the first thickened region 311 is the thickness at any location in the first thickened region 311.

[0107] Optionally, a first thickened area 311 close to the first main body portion 32 may be a thickened structure, and the thickness of the first thickened area 311 may gradually decrease from an end away from the first main body portion 32 to an end close to the first main body portion 32 .

[0108] In some embodiments, the first body portion 32 may be a uniform thickness structure to facilitate processing and manufacturing. When the first body portion 32 is a uniform thickness structure, the thickness of the first body portion 32 is the thickness at any position of the first body portion 32 .

[0109] In some other embodiments, the first body portion 32 may also be a thickened structure. In this case, the thickness of the first body portion 32 may be the maximum thickness of the first body portion 32 .

[0110] In some embodiments, the first transition zone 312 can be a uniform thickness structure, for example, the thickness of the first transition zone 312 can be equal to the thickness of the first main body portion 32; or, the first transition zone 312 can also be a variable thickness structure, and the maximum thickness of the first transition zone 312 can be greater than or equal to the thickness of the first main body portion 32.

[0111] The maximum thickness of the first transition zone 312 may be greater than or equal to the thickness of the first body portion 32 , so that the first transition zone 312 may be thickened relative to the first body portion 32 , further enhancing the strength of the first opening portion 31 .

[0112] In some embodiments, the first body portion 32 has a second surface facing the interior of the battery cell 20 , and the first thickened region 311 may protrude from the second surface.

[0113] In some embodiments, the first body portion 32 has a third surface facing away from the interior of the battery cell 20 , and the first thickened area 311 may protrude from the third surface.

[0114] In some embodiments, the first body portion 32 has a second surface facing the interior of the battery cell 20 and a third surface facing away from the interior of the battery cell 20 , and the first thickened area 311 may protrude from the second surface and the third surface.

[0115] In some embodiments, the first thickened area 311 may be an area formed after the main body of the first wall 30 is thickened. For example, in the area where the first thickened area 311 is located, the main body of the first wall 30 and the thickening component are connected to form the first thickened area 311.

[0116] In some embodiments, the first wall 30 can be integrally formed. For example, the first opening portion 31 and the first main body portion 32 can be stamped; alternatively, the first transition region 312 and the first main body portion 32 can be formed by thinning. The first transition region 312 is located between two adjacent first thickened regions 311, and the first thickened region 311 is connected to the first main body portion 32.

[0117] In the battery cell 20 of the embodiment of the present application, the first opening portion 31 includes multiple first thickened regions 311 spaced apart along the first direction X. The maximum thickness of the first thickened regions 311 is greater than the thickness of the first main body portion 32. The first thickened regions 311 are thickened relative to the first main body portion 32, thereby enhancing the strength of the first opening portion 31 and reducing the risk of cracking in the area of ​​the housing 211 near the weld between the housing 211 and the end cap 212. This ensures a longer service life and greater reliability for the battery cell 20. Furthermore, the multiple first thickened regions 311 spaced apart along the first direction X facilitate the expansion of the material during stamping of the housing 211, thereby reducing the manufacturing difficulty of the battery cell 20.

[0118] Please refer to Figures 5 and 6. According to some embodiments of the present application, the difference between the maximum thickness of the first thickened area 311 and the thickness of the first main body portion 32 is greater than or equal to 0.05 mm, and the difference between the maximum thickness of the first thickened area 311 and the thickness of the first main body portion 32 is less than or equal to the thickness of the first main body portion 32.

[0119] The thickness of the first main body portion 32 is W1, and the maximum thickness of the first thickened area 311 is W2, satisfying 0.05 mm ≤ W2 - W1 ≤ W1.

[0120] The first body portion 32 may have a uniform thickness, and W1 may be the thickness at any position of the first body portion 32 .

[0121] W2 - W1 may be the maximum thickness of the first thickened area 311 relative to the first body portion 32 .

[0122] Optionally, W2-W1 may be, but is not limited to, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.5*W1, 0.6*W1, 0.7*W1, 0.8*W1, 0.9*W1, W1, etc.

[0123] In the above scheme, the difference between the maximum thickness of the first thickened area 311 and the thickness of the first main body portion 32 satisfies the above relationship (0.05mm≤W2-W1≤W1). On the one hand, when W2-W1≥0.05mm, the first thickened area 311 has higher strength, so that the first opening portion 31 has higher strength; on the other hand, when W2-W1≤W1, the first thickened area 311 occupies less space, so that the battery cell 20 has a higher energy density.

[0124] According to some embodiments of the present application, 0.2 mm ≤ W2 - W1 ≤ 0.8*W1.

[0125] In the above solution, compared with W2-W1<0.2mm, when W2-W1≥0.2mm, the first thickened area 311 is further made to have higher strength, and the first opening portion 31 is further made to have higher strength; compared with W2-W1>0.8*W1, when W2-W1≤0.8*W1, the space occupied by the first thickened area 311 is further made smaller, so that the battery cell 20 has higher reliability.

[0126] According to some embodiments of the present application, the maximum thickness of the first thickened area 311 is greater than or equal to 0.25 mm, and the maximum thickness of the first thickened area 311 is less than or equal to 2.4 mm.

[0127] Optionally, W2 can be but is not limited to 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, etc.

[0128] In the above scheme, the maximum thickness of the first thickened area 311 satisfies the above relationship (0.25mm≤W2≤2.4mm). On the one hand, when W2≥0.25mm, the first thickened area 311 has higher strength. On the other hand, when W2≤2.4mm, the first thickened area 311 occupies less space in the thickness direction of the first wall 30, and has less impact on the energy density of the battery cell 20.

[0129] According to some embodiments of the present application, 0.8 mm ≤ W2 ≤ 1.8 mm.

[0130] Optionally, W2 can be but is not limited to 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, etc.

[0131] In the above scheme, compared with W2<0.8mm, when W2≥0.8mm, the strength of the first thickened area 311 is further enhanced, so that the first opening portion 31 has higher strength; compared with W2>1.8mm, when W2≤1.8mm, the first thickened area 311 further occupies a smaller space in the thickness direction of the first wall 30, reducing the impact on the energy density of the battery cell 20.

[0132] According to some embodiments of the present application, the thickness of the first body portion 32 is greater than or equal to 0.2 mm, and the thickness of the first body portion 32 is less than or equal to 1.2 mm.

[0133] Optionally, W1 can be but is not limited to 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, etc.

[0134] In the above scheme, the thickness of the first main body portion 32 satisfies the above relationship (0.2mm≤W1≤1.2mm). On the one hand, when W1≥0.2mm, the first main body portion 32 has higher strength, so that the first wall 30 has higher strength; on the other hand, when W1≤1.2mm, the first main body portion 32 occupies less space in the thickness direction of the first wall 30, so that the battery cell 20 has a higher energy density.

[0135] According to some embodiments of the present application, 0.6 mm ≤ W1 ≤ 1 mm.

[0136] Optionally, W1 may be, but is not limited to, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, etc.

[0137] In the above solution, compared to W1 < 0.6 mm, when W1 ≥ 0.6 mm, the first body portion 32 has higher strength, thereby increasing the strength of the first wall 30. Compared to W1 > 1 mm, when W1 ≤ 1 mm, the first body portion 32 occupies less space in the thickness direction of the first wall 30, thereby increasing the energy density of the battery cell 20.

[0138] According to some embodiments of the present application, referring to FIG. 5 , the maximum thickness of the first transition region may be W7, satisfying W7 ≥ W1.

[0139] Optionally, 0<W2-W7≤W1.

[0140] Referring to FIG. 6 , according to some embodiments of the present application, along the first direction X, the distance between two adjacent first thickened areas 311 is greater than or equal to 2 mm, and the distance between two adjacent first thickened areas 311 is less than or equal to 15 mm.

[0141] Along the first direction X, the distance between two adjacent first thickened areas 311 is h1, which satisfies 2 mm ≤ h1 ≤ 15 mm.

[0142] Alternatively, h1 may be, but is not limited to, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.

[0143] In the above scheme, the distance between two adjacent first thickened areas 311 satisfies the above relationship (2mm≤h1≤15mm). On the one hand, when h1≤15mm, the strength of the first opening portion 31 can be improved. On the other hand, when h1≥2mm, it can facilitate the extension of the material during stamping of the shell 211.

[0144] According to some embodiments of the present application, 5 mm ≤ h1 ≤ 10 mm.

[0145] Optionally, h1 can be but is not limited to 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc.

[0146] In the above scheme, compared with h1<5mm, when h1≥5mm, it is further facilitated to extend the material during the stamping of the shell 211; compared with h1>10mm, when h1≤10mm, it further makes the first opening portion 31 have higher strength, reducing the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212.

[0147] According to some embodiments of the present application, the number of the first thickened regions 311 is 2 or 3.

[0148] The more the number of the first thickened areas 311 is, the larger the space occupied by the first opening 31 in the first direction X is, and the first opening 31 is more likely to interfere with other components inside the battery cell 20 .

[0149] For example, referring to FIG. 5 and FIG. 6 , the number of the first thickened areas 311 is 2, the number of the first transition area 312 is 1, and the first thickened area 311 , the first transition area 312 , the first thickened area 311 and the first body portion 32 are distributed in sequence along the first direction X.

[0150] In the above solution, the number of the first thickened areas 311 is 2 or 3. While making the first opening portion 31 have a higher strength, the size occupied by the multiple first thickened areas 311 in the first direction X can be smaller, reducing the risk of interference between the first thickened areas 311 and other components.

[0151] Please refer to Figure 5. According to some embodiments of the present application, multiple first thickened areas 311 include a first sub-thickened area 311a and a second sub-thickened area 311b. The first sub-thickened area 311a and the second sub-thickened area 311b are spaced apart along the first direction X. The first sub-thickened area 311a is closer to the opening 213 (please refer to Figure 3) than the second sub-thickened area 311b. The end cover 212 is welded to the first sub-thickened area 311a. Along the first direction X, the maximum thickness of the first sub-thickened area 311a is equal to the maximum thickness of the second sub-thickened area 311b. The thickness of the second sub-thickened area 311b gradually decreases from an end close to the first sub-thickened area 311a toward an end away from the first sub-thickened area 311a.

[0152] The first sub-thickened region 311a is the region of the multiple first thickened regions 311 that connects to the end cap 212. The first sub-thickened region 311a and the end cap 212 are welded to form the first fusion zone 214. Before the housing 211 and the end cap 212 are assembled, the first sub-thickened region 311a can be a uniform thickness structure. That is, the thickness of the first sub-thickened region 311a is the same at any position along the first direction X. After the housing 211 and the end cap 212 are welded, the maximum thickness of the first sub-thickened region 311a can be greater than the thickness of the first body portion 32.

[0153] In the above solution, the first sub-thickened area 311a and the second sub-thickened area 311b are spaced apart along the first direction X, so that the first opening portion 31 has higher strength, which can reduce the risk of the shell 211 cracking near the connection position between the shell 211 and the end cover 212.

[0154] Please refer to Figures 5 and 6. According to some embodiments of the present application, the multiple first thickened areas 311 include a first sub-thickened area 311a closest to the opening 213, and the end cover 212 is welded to the first sub-thickened area 311a; wherein, along the first direction, the difference between the size of the first sub-thickened area and the thickness of the end cover is greater than or equal to 0, and the difference between the size of the first sub-thickened area and the thickness of the end cover is less than or equal to 2 times the thickness of the end cover.

[0155] The thickness of the end cover 212 is h2. Along the first direction X, the size of the first sub-thickened area 311a is h3, satisfying 0≤h3-h2≤2*h2.

[0156] The first sub-thickened region 311 a is a portion of the plurality of first thickened regions 311 used for connecting with the end cover 212 .

[0157] The end cover 212 and the first sub-thickened area 311 a are welded to form a first fusion zone 214 , which may be referred to as a weld mark.

[0158] Optionally, h3-h2 can be but is not limited to 0.1*h2, 0.2*h2, 0.3*h2, 0.4*h2, 0.5*h2, 0.6*h2, 0.7*h2, 0.8*h2, 0.9*h2, h2, 1.1*h2, 1.2*h2, 1.3*h2, 1.4*h2, 1.5*h2, 1.6*h2, 1.7*h2, 1.8*h2, 1.9*h2, 2*h2, etc.

[0159] In the above scheme, the end cover 212 is connected to the first sub-thickened area 311a, and the difference between the size of the first thickened area 311 in the first direction X and the thickness of the end cover 212 satisfies the above relationship. On the one hand, when h3-h2≥0, the connection between the end cover 212 and the shell 211 is stable, and the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212 is reduced; on the other hand, when h3-h2≤2*h2, the space occupied by multiple first thickened areas 311 in the first direction X is small, reducing the risk of interference between multiple first thickened areas 311 and other components.

[0160] According to some embodiments of the present application, 0≤h3-h2≤1.2*h2.

[0161] Optionally, h3-h2 can be but is not limited to 0.2*h2, 0.4*h2, 0.6*h2, 0.8*h2, h2, 1.2*h2, etc.

[0162] In the above scheme, compared with h3-h2>1.2*h2, when h3-h2≤1.2*h2, the space occupied by the first sub-thickening area 311a in the first direction X is reduced, and the space occupied by the multiple first thickening areas 311 in the first direction X is further reduced, thereby reducing the risk of interference between the multiple first thickening areas 311 and other components.

[0163] Please refer to Figure 3. According to some embodiments of the present application, there are two first walls 30, and the two first walls 30 are arranged opposite to each other in the second direction Y; the shell 211 also includes two second walls 40 arranged opposite to each other in the third direction Z. The two first walls 30 and the two second walls 40 form an opening 213. The first direction X, the second direction Y and the third direction Z are perpendicular to each other, and the area of ​​the outer surface of the first wall 30 is larger than the area of ​​the outer surface of the second wall 40.

[0164] In the figure, the direction indicated by letter Y may be the second direction, which may be parallel to the width direction of the battery cell 20. The direction indicated by letter Z may be the third direction, which may be parallel to the length direction of the battery cell 20.

[0165] Both ends of the first wall 30 in the third direction Z are connected to the two second walls 40 , and both ends of the second wall 40 in the second direction Y are connected to the two first walls 30 , so that the two first walls 30 and the two second walls 40 form an opening 213 .

[0166] In some embodiments, the outer surface area of ​​the first wall 30 is larger than the outer surface area of ​​the end cover 212 . The first wall 30 may be a large surface of the shell 211 , and the second wall 40 may be a side surface of the shell 211 .

[0167] In the above solution, the first wall 30 can be the large surface of the shell 211. Setting the first thickened area 311 can enhance the strength of the first wall 30 and reduce the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212.

[0168] Please refer to Figures 7 and 8. Figure 7 is a schematic diagram of the assembly of the end cover and the second wall provided in some embodiments of the present application. Figure 8 is a schematic diagram of the structure of the second wall provided in some embodiments of the present application. Figure 8 is a schematic diagram of the structure of the second wall before the end cover and the shell are assembled. According to some embodiments of the present application, the second wall 40 includes a second opening portion 41 and a second main body portion 42 distributed in sequence along the first direction X. The second opening portion 41 is close to the opening 213 relative to the second main body portion 42. The second opening portion 41 includes a plurality of second thickened areas 411 and at least one second transition area 412. The plurality of second thickened areas 411 are spaced apart along the first direction X. Two adjacent second thickened areas 411 are connected by the second transition area 412. The plurality of second thickened areas 411 include a third sub-thickened area 411a and At least one fourth sub-thickening zone 411b, the third sub-thickening zone 411a is closest to the opening 213, the end cover 212 is welded to the third sub-thickening zone 411a, the difference between the maximum thickness of the third sub-thickening zone 411a and the thickness of the second main body portion 42 is greater than 0.2 mm, the maximum thickness of the fourth sub-thickening zone 411b is greater than the thickness of the second main body portion 42, the maximum thickness of the fourth sub-thickening zone 411b is greater than the maximum thickness of the second transition zone 412, and the maximum thickness of the second transition zone 412 is greater than or equal to the thickness of the second main body portion 42.

[0169] The thickness of the second main body portion 42 is W3, the maximum thickness of the third sub-thickening area 411a is W4, the maximum thickness of the fourth sub-thickening area 411b is W5, and the maximum thickness of the second transition area 412 is W6, satisfying W4>W3-0.2mm, W5>W3, W5>W6, and W6≥W3.

[0170] Along the first direction X, the second opening portions 41 and the second body portions 42 are sequentially distributed. The second opening portions 41 form an opening 213 , and the end cover 212 is connected to the second opening portion 41 .

[0171] The third sub-thickened region 411 a is closer to the opening 213 than the second transition region 412 and the fourth sub-thickened region 411 b , and the third sub-thickened region 411 a constitutes a portion of the opening 213 .

[0172] The plurality of second thickened regions 411 are spaced apart along the first direction X, and the second transition region 412 separates two adjacent second thickened regions 411, such that the second thickened regions 411 and the second transition region 412 are staggered in the first direction X to facilitate the expansion of the material during stamping of the housing 211. For example, when the plurality of second thickened regions 411 include a third sub-thickened region 411a and a fourth sub-thickened region 411b, the third sub-thickened region 411a, the second transition region 412, the fourth sub-thickened region 411b, and the second body portion 42 are sequentially distributed along the first direction X.

[0173] During the battery cell 20 manufacturing process, when the end cap 212 is assembled with the housing 211, the side opening of the housing 211 is typically thinned. For example, the side opening is approximately 0.2 mm smaller than the side main body portion to facilitate welding of the end cap 212 to the housing 211. The third sub-thickened region 411a is the area of ​​the second wall 40 that is connected to the end cap 212. Along the first direction X, the end cap 212 and the third sub-thickened region 411a are welded to form a second weld zone 215, which can be referred to as a weld mark. The maximum thickness W4 of the third sub-thickened region 411a satisfies the aforementioned relationship with the thickness W3 of the second main body 42 (W4 > W3 - 0.2 mm). The second thickened region 411 has high strength, which can enhance the strength of the second opening 41 and reduce the risk of cracking in the area of ​​the housing 211 near the weld between the housing 211 and the end cap 212.

[0174] Optionally, W4 ≥ W3, so that the third sub-thickened area 411 a can be thickened compared to the opening on the side of the conventional shell 211, thereby improving the strength of the second opening portion 41.

[0175] Optionally, the maximum thickness W5 of the fourth sub-thickening region 411 b and the maximum thickness W4 of the third sub-thickening region 411 a satisfy W5 ≥ W4.

[0176] In some embodiments, before the housing 211 and the end cap 212 are assembled, the third sub-thickened region 411a can be a uniform thickness structure to facilitate manufacturing. After the end cap 212 is welded to the third sub-thickened region 411a, a portion of the third sub-thickened region 411a forms a second heat-melting zone, and the third sub-thickened region 411a becomes a thickened structure. The maximum thickness of the third sub-thickened region 411a can be greater than the thickness of the second body portion 42, thereby ensuring a secure connection between the second wall 40 and the end cap 212.

[0177] When W5>W6, W6≥W3, the second opening portion 41 is thickened relative to the second main body portion 42, so that the second opening portion 41 has higher strength, which can effectively reduce the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212, effectively extend the service life of the shell 211, and improve the reliability of the battery cell 20.

[0178] In the above scheme, the second wall 40 is the side (or narrow side) of the shell 211, the third sub-thickened area 411a is closest to the opening 213, the third sub-thickened area 411a is connected to the end cover 212, and the maximum thickness of the third sub-thickened area 411a, the maximum thickness of the fourth sub-thickened area 411b, and the maximum thickness of the second transition area 412 satisfy the above relationship, so that the second wall 40 is firmly connected to the end cover 212, and the second opening portion 41 has higher strength, reducing the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212; at the same time, multiple second thickened areas 411 are arranged at intervals along the first direction X, which can facilitate the extension of the material when the shell 211 is stamped and formed, thereby reducing the manufacturing difficulty of the battery cell 20.

[0179] In some embodiments, the second thickened area 411 may be an area formed after the main body of the second wall 40 is thickened. For example, in the area where the second thickened area 411 is located, the main body of the second wall 40 and the thickening component are connected to form the second thickened area 411.

[0180] In some embodiments, the second wall 40 may be integrally formed. For example, the second opening portion 41 and the second body portion 42 may be stamped. Alternatively, the second transition region 412 and the second body portion 42 may be formed by skiving.

[0181] Please refer to Figures 7 and 8. According to some embodiments of the present application, at least one second transition zone 412 includes a first sub-transition zone 412a connected to the third sub-thickening zone 411a. The maximum thickness of the first sub-transition zone 412a is greater than the maximum thickness of the third sub-thickening zone 411a. A first step surface 413 is formed between the first sub-transition zone 412a and the third sub-thickening zone 411a, and the end cover 212 is overlapped on the first step surface 413.

[0182] The first sub-transition region 412a connects the third sub-thickened region 411a and the fourth sub-thickened region 411b. The first sub-transition region 412a can have a gradually thickening structure, with the thickness of the first sub-transition region 412a gradually increasing from the third sub-thickened region 411a toward the fourth sub-thickened region 411b, thereby forming a first stepped surface 413 between the first sub-transition region 412a and the third sub-thickened region 411a. When the end cap 212 is assembled with the housing 211, the end cap 212 can overlap the first stepped surface 413 to facilitate positioning of the end cap 212.

[0183] In the above scheme, the maximum thickness of the first sub-transition zone 412a is greater than the maximum thickness of the third sub-thickening zone 411a, so that the second opening portion 41 has higher strength, reducing the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212. The setting of the first step surface 413 facilitates the positioning of the end cover 212 and the assembly of the end cover 212 and the shell 211.

[0184] Referring to FIG. 8 , according to some embodiments of the present application, along the first direction X, a distance between two adjacent second thickened areas 411 is h4, satisfying 2 mm ≤ h4 ≤ 15 mm.

[0185] Optionally, 5mm≤h4≤10mm.

[0186] According to some embodiments of the present application, along the first direction X, the size of the third sub-thickened area 411 a is h5, satisfying 0≤h5-h2≤2*h2.

[0187] According to some embodiments of the present application, 0.3 mm ≤ W5 ≤ 2.5 mm.

[0188] Optionally, 0.9mm≤W5≤1.9mm.

[0189] Optionally, W5 can be but not limited to 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, etc.

[0190] According to some embodiments of the present application, 0.3 mm ≤ W3 ≤ 1.3 mm.

[0191] Optionally, 0.7mm≤W3≤1.1mm.

[0192] Optionally, W3 may be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, etc.

[0193] According to some embodiments of the present application, 0.3 mm ≤ W4 ≤ 1.3 mm.

[0194] Optionally, 0.7mm≤W4≤1.1mm.

[0195] Optionally, W4 may be, but is not limited to, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, etc.

[0196] According to some embodiments of the present application, 0.25 mm ≤ W6 ≤ 2.4 mm.

[0197] Optionally, 0.8mm≤W6≤1.8mm.

[0198] Optionally, W6 can be but not limited to 0.25mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, etc.

[0199] 5 , according to some embodiments of the present application, the end cap 212 has a first surface 212 a facing away from the interior of the battery cell 20 , and along the first direction X, a maximum distance between one end of the plurality of first thickened regions 311 facing away from the first surface 212 a and the first surface 212 a is less than or equal to 10 mm.

[0200] The maximum distance between the first surface 212a and one end of the plurality of first thickened regions 311 facing away from the first surface 212a may be h6, satisfying h6≤10 mm.

[0201] The maximum distance between one end of the multiple first thickened areas 311 facing away from the first surface 212a and the first surface 212a refers to the maximum distance between one end of the multiple first thickened areas 311 facing away from the first surface 212a and the first surface 212a, that is, the maximum distance between one end of the first thickened area 311 closest to the first main body 32 among the multiple first thickened areas 311 facing away from the first surface 212a and the first surface 212a.

[0202] The first thickened area 311 is welded to the end cover 212 to form a first fusion zone 214. The area near the first fusion zone 214 forms a heat-affected zone. The strength of the portion of the shell 211 in the heat-affected zone is weakened. The maximum thickness of the first thickened area 311 is greater than the thickness of the first main body 32, so that the strength of the first thickened area 311 is enhanced. When the maximum distance between the end of the plurality of first thickened areas 311 facing away from the first surface 212a and the first surface 212a along the first direction X is less than or equal to 10 mm, it can not only enhance the strength of the first thickened area 311, but also facilitate demolding of the shell 211 during the manufacturing process, thereby facilitating manufacturing.

[0203] According to some embodiments of the present application, the end cover 212 has a first surface 212a facing away from the interior of the battery cell 20 , and along the first direction X, the maximum distance between one end of the plurality of second thickened regions 411 facing away from the first surface 212a and the first surface 212a is less than or equal to 10 mm.

[0204] The maximum distance between one end of the multiple second thickened areas 411 facing away from the first surface 212a and the first surface 212a refers to the maximum distance between one end of the multiple second thickened areas 411 facing away from the first surface 212a and the first surface 212a, that is, the maximum distance between one end of the second thickened area 411 closest to the second main body 42 among the multiple second thickened areas 411 facing away from the first surface 212a and the first surface 212a.

[0205] The second thickened area 411 is welded to the end cover 212 to form a second fusion zone, and the area near the second fusion zone forms a heat-affected zone. The strength of the portion of the shell 211 in the heat-affected zone becomes weaker. The maximum thickness of the second thickened area 411 is greater than the thickness of the second main body 42, so that the strength of the second thickened area 411 is enhanced. When the maximum distance between the end of the plurality of second thickened areas 411 facing away from the first surface 212a and the first surface 212a along the first direction X is less than or equal to 10 mm, it can not only enhance the strength of the second thickened area 411, but also facilitate demolding of the shell 211 during the processing and manufacturing process, thereby facilitating processing and manufacturing.

[0206] Please refer to Figure 3. According to some embodiments of the present application, there are two first walls 30, and the two first walls 30 are arranged opposite to each other in the second direction Y. The shell 211 also includes a bottom wall 216 and two second walls 40 arranged opposite to each other in the third direction Z. The two first walls 30 and the two second walls 40 surround an opening 213. Along the first direction X, the bottom wall 216 is arranged opposite to the opening 213, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0207] There is one opening 213 and one end cover 212. Two first walls 30 and two second walls 40 are arranged around the edge of the bottom wall 216. One end of the two first walls 30 away from the end cover 212 is connected to the bottom wall 216, and one end of the two second walls 40 away from the end cover 212 is connected to the bottom wall 216.

[0208] The bottom wall and the opening 213 are disposed opposite to each other in the first direction X. During the assembly of the battery cell 20 , when the electrode assembly 22 is disposed in the housing 211 , the bottom wall 216 can support the electrode assembly 22 .

[0209] In some embodiments, the two first walls 30 , the two second walls 40 and the bottom wall 216 are integrally formed, which is convenient for processing and manufacturing, and the housing 211 has high strength.

[0210] According to some embodiments of the present application, the housing 211 is a prismatic structure having openings 213 at both ends. There are two end covers 212 , and the two end covers 212 respectively close the two openings 213 .

[0211] When the housing 211 is a prismatic structure, the battery cell 20 may be a square battery. In other embodiments, the housing 211 may be a hexagonal prism, an octagonal prism, or the like.

[0212] When the positive electrode tab and the negative electrode tab are arranged at both ends of the electrode assembly, the shell 211 has two openings 213, and the positive electrode terminal and the negative electrode terminal can be respectively arranged on the two end covers 212 so as to be electrically connected to the positive electrode tab and the negative electrode tab respectively, so as to facilitate charging and discharging of the battery cell 20.

[0213] In the above embodiment, the housing 211 has two openings 213, and the two end caps 212 respectively close the two openings 213 to facilitate assembly of the electrode assembly and the housing 211. An opening 213 is provided at each end of the housing 211, and a first opening portion 31 is provided at each end of the first wall 30 in the first direction X. The first opening portion 31 at each end in the first direction X encloses a corresponding opening 213. The provision of the first thickened region 311 can enhance the strength of the housing 211 near the opening 213, thereby reducing the risk of cracking of the housing 211 near the weld area between the housing 211 and the end caps 212.

[0214] According to some embodiments of the present application, an embodiment of the present application further provides a battery 100 , which includes a battery cell 20 provided in any of the above embodiments.

[0215] Please refer to Figures 9 to 11. Figure 9 is a schematic diagram of the assembly of an end plate and a battery cell group according to some embodiments of the present application. Figure 10 is a schematic diagram of the assembly of an end plate and a battery cell according to some embodiments of the present application. Figure 11 is a partial enlarged view of point B in Figure 10. According to some embodiments of the present application, there are multiple battery cells 20, and the multiple battery cells 20 are stacked along a second direction Y to form a battery cell group 20a. The second direction Y is parallel to the thickness direction of the first wall 30. The battery 100 also includes an end plate 50. The end plate 50 is disposed at an end of the battery cell group 20a along the second direction Y, along the first body portion 32 toward the first opening portion 31, and at least a portion of the first opening portion 31 extends beyond the end plate 50.

[0216] Multiple battery cells 20 are stacked along the second direction Y. Along the second direction Y, the end plate 50 is arranged at the end of the battery cell group 20a. The end plate 50 is connected to the battery cell 20 at the end of the battery cell group 20a located in the second direction Y. The end plate 50 can limit the battery cell 20 at the end and restrain the deformation of the battery cell 20.

[0217] In the above scheme, the end plate 50 is arranged at the end of the battery cell group 20a in the third direction Z, and the end plate 50 has a large connection area with the shell 211 of the adjacent battery cell 20 to form a constraint on the shell 211, thereby reducing the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212.

[0218] According to some embodiments of the present application, the end plate 50 is disposed facing the first wall 30 .

[0219] In the above scheme, the end plate 50 is arranged facing the first wall 30, and the end plate 50 has a large contact area with the first main body portion 32. During the charge and discharge cycle of the battery cell 20, the end plate 50 can constrain the first wall 30 to reduce the risk of cracking of the shell 211 in the area near the welding position of the shell 211 and the end cover 212.

[0220] According to some embodiments of the present application, an electrical device is further provided, which includes a battery cell 20 or a battery 100 as provided in any of the above embodiments, and the battery cell 20 or the battery 100 is used to provide electrical energy.

[0221] The electrical equipment may be any of the above-mentioned systems or devices using the battery cell 20 or the battery 100 , and the battery cell 20 or the battery 100 is used to provide electrical energy.

[0222] According to some embodiments of the present application, an energy storage device is further provided, which includes a battery cell 20 or a battery 100 as provided in any of the above embodiments.

[0223] According to some embodiments of the present application, please refer to Figures 3 to 7. The embodiments of the present application provide a battery cell 20, which is a rectangular parallelepiped. The battery cell 20 includes an outer shell 21 and an electrode assembly, and the electrode assembly is disposed in the outer shell 21. The outer shell 21 includes a shell 211 and an end cover 212. The shell 211 has an opening 213, and the end cover 212 closes the opening 213. The shell 211 includes two first walls 30 arranged opposite to each other along the second direction Y, two second walls 40 arranged opposite to each other along the third direction Z, and a bottom wall 216. The first wall 30 is connected to the two second walls 40 at both ends in the third direction Z. The two first walls 30 and the two second walls 40 enclose the opening 213. Along the first direction X, the bottom wall 216 is arranged opposite to the opening 213. The area of ​​the outer surface of the first wall 30 is larger than the area of ​​the outer surface of the second wall 40. The first wall 30 includes a first opening portion 31 and a first main body portion 32, arranged sequentially along the first direction X. The first main body portion 32 is spaced apart from the opening 213 relative to the first opening portion 31, and the end cap 212 is welded to the first opening portion 31. The first opening portion 31 includes multiple first thickened regions 311 and at least one first transition region 312. The multiple first thickened regions 311 are spaced apart along the first direction X, and two adjacent first thickened regions 311 are connected by the first transition region 312. The maximum thickness of the first thickened regions 311 is greater than the thickness of the first main body portion 32, and the maximum thickness of the first transition region 312 is greater than or equal to the thickness of the first main body portion 32. The maximum thickness of the first thickened region 311 is greater than the maximum thickness of the first transition region 312. There are two first thickened regions 311 and one first transition region 312. The first thickened region 311 is connected to the first main body portion 32.

[0224] According to the battery cell 20 of the embodiment of the present application, the first opening portion 31 includes multiple first thickened regions 311 spaced apart along the first direction X. The maximum thickness of the first thickened regions 311 is greater than the thickness of the first main body portion 32. The first thickened regions 311 are thickened relative to the first main body portion 32, thereby enhancing the strength of the first opening portion 31 and reducing the risk of cracking in the area of ​​the housing 211 near the weld between the housing 211 and the end cap 212, thereby enhancing the service life and reliability of the battery cell 20. Furthermore, the multiple first thickened regions 311 are spaced apart along the first direction X, facilitating the expansion of the material during stamping of the housing 211 and reducing the manufacturing difficulty of the battery cell 20. The number of first thickened regions 311 is two. While ensuring the high strength of the first opening portion 31, the two first thickened regions 311 can occupy a smaller area in the first direction X, reducing the risk of interference between the first thickened regions 311 and other components.

[0225] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell, comprising: A housing comprising a shell and an end cap, wherein the shell has an opening and includes a first wall, wherein the first wall includes a first opening portion and a first body portion sequentially distributed along a first direction, wherein the first direction is parallel to a thickness direction of the end cap, the first body portion is away from the opening relative to the first opening portion, and the end cap is welded to the first opening portion to close the opening; In which, the first opening portion includes multiple first thickened areas and at least one first transition area, the multiple first thickened areas are arranged at intervals along the first direction, two adjacent first thickened areas are connected by the first transition area, the maximum thickness of the first thickened area is greater than the thickness of the first main body portion, the maximum thickness of the first transition area is greater than or equal to the thickness of the first main body portion, and the maximum thickness of the first thickened area is greater than the maximum thickness of the first transition area.

2. The battery cell according to claim 1, wherein: The difference between the maximum thickness of the first thickened area and the thickness of the first main body is greater than or equal to 0.05 mm, and the difference between the maximum thickness of the first thickened area and the thickness of the first main body is less than or equal to the thickness of the first main body.

3. The battery cell according to claim 2, wherein: The maximum thickness of the first thickened area is greater than or equal to 0.25 mm, and the maximum thickness of the first thickened area is less than or equal to 2.4 mm.

4. The battery cell according to any one of claims 1 to 3, wherein: Along the first direction, a distance between two adjacent first thickened areas is greater than or equal to 2 mm, and a distance between two adjacent first thickened areas is less than or equal to 15 mm.

5. The battery cell according to any one of claims 1 to 4, wherein: The number of the first thickened areas is 2 or 3.

6. The battery cell according to any one of claims 1 to 5, wherein: The multiple first thickening areas include a first sub-thickening area and a second sub-thickening area. The first sub-thickening area and the second sub-thickening area are spaced apart along the first direction. The first sub-thickening area is closer to the opening than the second sub-thickening area. The end cover is welded to the first sub-thickening area. Along the first direction, the maximum thickness of the first sub-thickening area is equal to the maximum thickness of the second sub-thickening area. The thickness of the second sub-thickening area gradually decreases from an end close to the first sub-thickening area to an end away from the first sub-thickening area.

7. The battery cell according to any one of claims 1 to 6, wherein: The plurality of first thickened regions include a first sub-thickened region closest to the opening, and the end cover is welded to the first sub-thickened region; Among them, along the first direction, the difference between the size of the first sub-thickened area and the thickness of the end cover is greater than or equal to 0, and the difference between the size of the first sub-thickened area and the thickness of the end cover is less than or equal to 2 times the thickness of the end cover.

8. The battery cell according to any one of claims 1 to 7, wherein: There are two first walls, and the two first walls are arranged opposite to each other in the second direction; The shell also includes two second walls arranged opposite to each other in a third direction, the two first walls and the two second walls surround the opening, the first direction, the second direction and the third direction are perpendicular to each other, and 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 battery cell according to claim 8, wherein: The second wall includes a second opening portion and a second main body portion distributed in sequence along the first direction, the second opening portion is close to the opening relative to the second main body portion, the second opening portion includes a plurality of second thickened areas and at least one second transition area, the plurality of second thickened areas are spaced apart along the first direction, any two adjacent second thickened areas are connected by the second transition area, the plurality of second thickened areas include a third sub-thickened area and at least one fourth sub-thickened area, the third sub-thickened area is closest to the opening, the end cover is welded to the third sub-thickened area, the difference between the maximum thickness of the third sub-thickened area and the thickness of the second main body portion is greater than 0.2 mm, the maximum thickness of the fourth sub-thickened area is greater than the thickness of the second main body portion, the maximum thickness of the fourth sub-thickened area is greater than the maximum thickness of the second transition area, and the maximum thickness of the second transition area is greater than or equal to the thickness of the second main body portion.

10. The battery cell according to claim 9, wherein: The at least one second transition zone includes a first sub-transition zone connected to the third sub-thickening zone, the maximum thickness of the first sub-transition zone is greater than the maximum thickness of the third sub-thickening zone, a first step surface is formed between the first sub-transition zone and the third sub-thickening zone, and the end cover overlaps the first step surface.

11. The battery cell according to any one of claims 1 to 10, wherein: The end cover has a first surface facing away from the interior of the battery cell. Along the first direction, a maximum distance between ends of the plurality of first thickened regions facing away from the first surface and the first surface is less than or equal to 10 mm.

12. The battery cell according to any one of claims 1 to 11, wherein: There are two first walls, and the two first walls are arranged opposite to each other in the second direction; The shell also includes a bottom wall and two second walls arranged opposite to each other in a third direction. The two first walls and the two second walls surround the opening. Along the first direction, the bottom wall and the opening are arranged opposite to each other. The first direction, the second direction and the third direction are perpendicular to each other.

13. The battery cell according to any one of claims 1 to 12, wherein: The shell is a prismatic structure with openings at both ends. There are two end covers, and the two end covers respectively close the two openings.

14. A battery comprising the battery cell according to any one of claims 1 to 13.

15. The battery according to claim 14, wherein There are multiple battery cells, and the multiple battery cells are stacked along a second direction to form a battery cell group. The second direction is parallel to the thickness direction of the first wall. The battery also includes an end plate. Along the second direction, the end plate is arranged at the end of the battery cell group, along the direction of the first main body pointing to the first opening, and at least a portion of the first opening exceeds the end plate. 16 . An electrical device comprising the battery cell according to claim 1 or the battery according to claim 14 , wherein the battery cell or the battery is used to provide electrical energy.

17. An energy storage device comprising the battery cell according to any one of claims 1 to 13 or the battery according to any one of claims 14 to 15.

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