Battery cell, battery, electric apparatus, and energy storage device

Abstract

Provided in the embodiments of the present application are a battery cell, a battery, an electric apparatus, and an energy storage device. The battery cell comprises a casing. The casing comprises a casing body and an end cap, wherein the casing body is provided with an opening and comprises two first walls arranged opposite each other in a first direction and two second walls arranged opposite each other in a second direction, and the area of an outer surface of the first wall is smaller than the area of an outer surface of the second wall; the first wall comprises a first opening portion and a first body portion, which are distributed in sequence in a third direction, the third direction being parallel to the thickness direction of the end cap, and the first body portion being far away from the opening relative to the first opening portion; the end cap is connected to the first walls and the second walls and seals the opening; the dimension of the first wall in the second direction is W1, the dimension of the second wall in the first direction is W2, and the dimensions satisfy 0.2≤W1 / W2; and the thickness of the first opening portion is greater than the thickness of the first body portion, and the second direction, the third direction and the first direction are perpendicular to each other in a pairwise manner. On the basis of the technical solution in the present application, the reliability of the battery can be improved.

Description

Battery cells, batteries, electrical equipment and energy storage devices Technical Field

[0001] 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

[0002] 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.

[0003] 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.

[0004] 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.

[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, comprising a housing. The housing comprises a shell and an end cap, the shell having an opening, comprising two first walls disposed oppositely along a first direction and two second walls disposed oppositely along a second direction, the outer surface area of ​​the first wall being smaller than the outer surface area of ​​the second wall, the first wall comprising a first opening portion and a first body portion sequentially distributed along a third direction, the third direction being parallel to the thickness direction of the end cap, the first body portion being further away from the opening than the first opening portion, and the end cap being connected to the first and second walls and sealing the opening; wherein the first wall has a dimension W1 in the second direction and a dimension W2 in the first direction, satisfying the condition 0.2 ≤ W1 / W2, the maximum thickness of the first opening portion is greater than the thickness of the first body portion, and the second, third, and first directions are perpendicular to each other.

[0008] According to the battery cell of the embodiment of the present application, the area of ​​the outer surface of the first wall is smaller than the area of ​​the outer surface of the second wall. The first wall can be the narrow surface of the battery cell. When the ratio of the size of the first wall in the second direction to the size of the second wall in the first direction satisfies the above relationship, the first opening portion is thickened so that the first opening portion has higher strength, which can reduce the risk of cracking of the shell near the welding area of ​​the shell and the end cover when the battery cell is in thermal runaway or the gas production is too large, so that the battery cell has higher reliability.

[0009] According to some embodiments of the present application, W1 / W2≤0.6.

[0010] In the above scheme, when the ratio of the size of the first wall in the second direction to the size of the second wall in the first direction satisfies the above relationship, the risk of cracking of the shell near the welding area of ​​the shell and the end cover can be reduced while making the first opening portion have higher strength.

[0011] According to some embodiments of the present application, 0.25≤W1 / W2≤0.35.

[0012] In the above solution, compared with 0.2≤W1 / W2, when 0.25≤W1 / W2≤0.35, the thickening treatment of the first opening portion can effectively reduce the risk of cracking of the shell near the welding area between the shell and the end cover, while also improving the manufacturability of the shell and further improving the reliability of the battery cell.

[0013] According to some embodiments of the present application, 50 mm ≤ W1 ≤ 90 mm, optionally, 60 mm ≤ W1 ≤ 86 mm.

[0014] In the above solution, when the dimensions of the first wall in the second direction satisfy the above relationship, the thickening of the first opening can, on the one hand, improve the strength of the first opening and reduce the risk of cracking of the shell near the weld area between the shell and the end cap, and on the other hand, facilitate manufacturing. Compared to 50mm≤W1≤90mm, when 60mm≤W1≤86mm, the thickening of the first opening can reduce the risk of cracking of the shell near the weld area between the shell and the end cap, and reduce the difficulty of manufacturing.

[0015] According to some embodiments of the present application, the maximum thickness of the first opening portion is h1, and the thickness of the first body portion is h2, satisfying 0.55≤h / W≤2.5, h=(h1-h2) / h2, and W=W1 / W2.

[0016] In the above scheme, the maximum thickness of the first opening portion, the thickness of the first main body portion, the dimension of the first wall in the second direction, and the dimension of the second wall in the first direction satisfy the above relationship. The first opening portion is thickened so that the first opening portion has higher strength, which can reduce the risk of cracking of the shell near the welding area between the shell and the end cover. In addition, it is convenient for processing and manufacturing the first opening portion, the first opening portion occupies less space, and the battery cell has a higher energy density.

[0017] According to some embodiments of the present application, 0.6≤h / W≤1.8.

[0018] In the above solution, compared with 0.55≤h / W≤2.5, when 0.6≤h / W≤1.8, the first opening occupies a smaller space, the processing and manufacturing difficulty of the first opening is lower, and the first opening has a higher strength.

[0019] According to some embodiments of the present application, the maximum thickness of the first opening is h1, the thickness of the first body is h2, and the area of ​​the outer surface of the first wall is S, which satisfies (1 / 360000) mm -2 ≤h / S≤(1 / 9000)mm -2 , h=(h1-h2) / h2.

[0020] In the above scheme, the maximum thickness of the first opening portion, the thickness of the first main body portion, and the area of ​​the outer surface of the first wall satisfy the above relationship, which is convenient for processing and manufacturing. The first opening portion has high strength and can reduce the risk of cracking of the shell near the welding area between the shell and the end cover. In addition, the first opening portion occupies a smaller space, and the battery cell has a higher energy density.

[0021] According to some embodiments of the present application, (1 / 300000) mm -2 ≤h / S≤(1 / 15000)mm -2 .

[0022] In the above scheme, compared with (1 / 360000) mm -2 ≤h / S≤(1 / 9000)mm -2 , when (1 / 300000) mm -2 ≤h / S≤ (1 / 15000)mm -2 When the first opening is provided, the processing and manufacturing difficulty is low, the first opening has high strength, and the space occupied by the first opening is small.

[0023] According to some embodiments of the present application, 4500mm 2 ≤S≤36000mm 2 .

[0024] In the above scheme, the area of ​​the outer surface of the first wall satisfies the above relationship, the battery cell has a high energy density, which facilitates the processing and manufacturing of the first wall, and the first opening has high strength, reducing the risk of cracking of the shell near the welding area between the shell and the end cover.

[0025] According to some embodiments of the present application, 6000mm 2 ≤S≤22500mm 2 .

[0026] In the above scheme, compared with 4500mm 2 ≤S≤36000mm 2 , when 6000mm 2 ≤S≤22500mm 2 When the battery cell has a higher energy density, the first opening has a higher strength, reducing the risk of the shell cracking near the welding area between the shell and the end cover.

[0027] According to some embodiments of the present application, h1 and h2 satisfy at least one of the following conditions: (1) 0.1≤h≤0.5; (2) 0.55mm≤h1≤1.8mm; (3) 0.5mm≤h2≤1.2mm.

[0028] In the above solution, the maximum thickness of the first opening portion and the thickness of the first main body portion satisfy the above relationship, which is convenient for processing and manufacturing. The first opening portion has higher strength, occupies less space, and the battery cell has higher energy density.

[0029] According to some embodiments of the present application, h1 and h2 satisfy at least one of the following conditions: (1) 0.15≤h≤0.3; (2) 0.69mm≤h1≤1.56mm; (3) 0.6mm≤h2≤0.8mm.

[0030] In the above scheme, compared with 0.1≤h≤0.5, 0.55mm≤h1≤1.8mm, 0.5mm≤h2≤1.2mm, when 0.15≤h≤0.3, 0.69mm≤h1≤1.56mm, 0.6mm≤h2≤0.8mm, the processing and manufacturing difficulty is lower, the strength of the first opening is higher, and the space occupied by the first opening is smaller.

[0031] According to some embodiments of the present application, the first opening portion includes a first section and a second section that are connected to each other, and the first section, the second section and the first main body portion are distributed in sequence along the third direction. The maximum thickness of the second section is greater than the thickness of the first main body portion, and the maximum thickness of the second section is greater than the maximum thickness of the first section. A first step surface is formed between the second section and the first section, and the end cover overlaps the first step surface and is connected to the first section.

[0032] In the above solution, the first section, second section, and first body are sequentially arranged along the third direction. The end cap is connected to the first section so that the second section is adjacent to the connection between the end cap and the first section. The first opening has high strength, which can reduce the risk of cracking of the shell near the weld area between the shell and the end cap, thereby improving the service life and reliability of the battery cell. The end cap overlaps the first step surface to facilitate positioning of the end cap.

[0033] According to some embodiments of the present application, the second wall includes a second opening portion and a second main body portion connected in sequence in a third direction, the second main body portion is farther away from the opening than the second opening portion, the second opening portion is connected to the end cover, and the maximum thickness of the second opening portion is greater than the thickness of the second main body portion.

[0034] In the above solution, the thickening treatment of the second opening portion can increase the strength of the second wall. During the charge and discharge cycle of the battery cell, the increased strength of the second opening portion can reduce the risk of fatigue cracking of the shell near the welding area between the shell and the end cover.

[0035] 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.

[0036] In the above solution, openings are respectively provided at both ends of the shell, and both openings are thickened to reduce the risk of cracking of the shell.

[0037] According to some embodiments of the present application, the battery cell also includes an electrode assembly, the electrode assembly includes a positive electrode plate, the positive electrode plate includes a positive electrode active material, the positive electrode active material includes a nickel-containing compound, the nickel-containing compound includes a layered lithium-containing transition metal oxide, and the ratio of the molar amount of the nickel element in the layered lithium-containing transition metal oxide to the total molar amount of the transition metal element in the layered lithium-containing transition metal oxide is not less than 50%.

[0038] In the above scheme, the nickel content is high and the battery cells have a higher energy density.

[0039] According to some embodiments of the present application, the layered lithium-containing transition metal oxide includes Li a Ni b Co c M d O e A f , wherein, 0<a≤1.2, 0.6≤b<1, 0<c<1; 0<d<1; 1≤e≤2; 0≤f≤1; M includes but is not limited to one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B; A includes but is not limited to one or more of N, F, S and Cl.

[0040] In the above solution, the nickel content is high, the energy density of the battery cell is high, and the first opening has high strength, which reduces the risk of the shell cracking near the welding area between the shell and the end cover.

[0041] According to some embodiments of the present application, 0.7≤b≤0.98.

[0042] In the above scheme, the nickel content is high and the battery cell has a higher energy density.

[0043] According to some embodiments of the present application, 0.4≤b / h≤8.1.

[0044] In the above solution, the battery cell is less difficult to manufacture, has a higher energy density, produces less gas due to thermal runaway, has a higher strength of the first wall, and has a lower risk of cracking of the first wall.

[0045] According to some embodiments of the present application, 1≤b / h≤6.

[0046] In the above solution, compared with 0.4≤b / h≤8.1, when 1≤b / h≤6, the strength of the first wall is higher and the space occupied by the first opening is smaller; the battery cell has a higher energy density and the battery cell produces less gas due to thermal runaway.

[0047] According to some embodiments of the present application, the battery cell also includes an electrode assembly, the electrode assembly includes a main body, the main body is provided with an active material, the main body has a first surface facing the end cover, and the first opening extends beyond the first surface along the direction of the first main body pointing to the first opening.

[0048] In the above solution, along the direction from the first body portion to the first opening portion, the first opening portion extends beyond the first surface, which can reduce the risk of interference between the first opening portion and the main body portion.

[0049] According to some embodiments of the present application, the shell and the end cover are welded to form a welding area, and the average grain size of the part of the first opening portion other than the welding area is larger than the average grain size of the first main body portion, and the average grain size is the average grain size of the grains in the thickness direction of the first wall.

[0050] In the above scheme, the average grain size of the first opening portion other than the welding area is larger than the average grain size of the first main body portion, which is beneficial to enhancing the strength of the first opening portion, so that the first opening portion has higher strength and reduces the risk of cracking of the shell near the welding area of ​​the shell and the end cover.

[0051] According to some embodiments of the present application, in a cross-section of the first wall parallel to the thickness direction of the first wall, the number of grains in a portion of the first opening below the welding area in the width direction of the cross-section is greater than or equal to 15.

[0052] In the above solution, the number of grains in the width direction of the cross section is greater than or equal to 15, which is beneficial to enhancing the strength of the first opening portion, so that the first opening portion has higher strength.

[0053] According to some embodiments of the present application, the average grain size of the first opening portion excluding the welding area is in a range of 70 μm-1200 μm; and / or the average grain size of the first body portion is in a range of 30 μm-1000 μm.

[0054] In the above solution, the average grain size of the first opening portion and / or the average grain size of the first body portion satisfy the above relationship, which is beneficial to enhancing the strength of the first opening portion, so that the first opening portion has higher strength.

[0055] In a second aspect, an embodiment of the present application provides a battery, which includes a battery cell provided in any of the above embodiments.

[0056] According to some embodiments of the present application, there are multiple battery cells, and the multiple battery cells are stacked along the second direction.

[0057] The battery further includes end plates, which are disposed at ends of the plurality of battery cells along the second direction.

[0058] In the above solution, the end plates are arranged at the ends of the multiple battery cells in the second direction, and the end plates have a larger connection area with the shells of adjacent battery cells to form a constraint on the shells, thereby reducing the risk of the shells cracking near the welding area between the shells and the end covers.

[0059] According to some embodiments of the present application, the end plate is arranged facing the second wall.

[0060] In the above solution, the end plate is arranged facing the second wall, and the end plate has a large connection area with the second wall. During the charge and discharge cycle of the battery cell, the end plate can constrain the second wall to reduce the risk of cracking of the shell near the welding area between the shell and the end cover.

[0061] In a third aspect, an embodiment of the present application provides an electrical device, which includes a battery cell or a battery as provided in any of the above embodiments.

[0062] In a fourth aspect, an embodiment of the present application provides an energy storage device, which includes a battery cell or a battery as provided in any of the above embodiments.

[0063] Additional aspects and advantages of the present application will be given in part in the description below and will become apparent in part from the description below.

[0064] Or learned through the practice of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] 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.

[0066] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0067] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0068] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0069] FIG4 is a perspective view of a battery cell provided in some embodiments of the present application;

[0070] FIG5 is a cross-sectional view of a housing provided in some embodiments of the present application;

[0071] FIG6 is a partial enlarged view of point A in FIG5 ;

[0072] FIG7 is a schematic structural diagram of a first wall provided in some embodiments of the present application;

[0073] FIG8 is a schematic structural diagram of a second wall provided in some embodiments of the present application;

[0074] FIG9 is a cross-sectional view of a partial structure of an assembled end cap and a housing according to some embodiments of the present application;

[0075] FIG10 is a schematic diagram of the assembly of an end plate and a plurality of battery cells provided in some embodiments of the present application;

[0076] FIG11 is a schematic diagram of the assembly of the end plate and the battery cells at the end provided in some embodiments of the present application.

[0077] In the drawings, the drawings are not drawn to scale.

[0078] Marking instructions: 100-battery; 10-case; 11-first sub-case; 12-second sub-case; 20-battery cell; 21-casing; 21a-shell; 21b-end cover; 211-first wall; 2111-first opening; 2111a-first section; 2111b-second section; 2112-first main body; 2113-first step surface; 212-second wall; 2121-second opening; 2122-second main body; 213-bottom wall; 210-welding area; 22-electrode assembly; 221-main body; 221a-first surface; 222-ear; 23-electrode terminal; 30-end plate; 200-controller; 300-motor; 1000-vehicle; X-third direction; Y-second direction; Z-first direction. DETAILED DESCRIPTION

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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).

[0085] 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.

[0086] 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.

[0087] 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.

[0088] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.).

[0095] 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.

[0096] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] In some embodiments, the electrode assembly is a laminate structure.

[0105] 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, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0106] 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.

[0107] 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.

[0108] In some embodiments, the housing is provided with an explosion-proof valve for releasing the internal pressure of the battery cell.

[0109] 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.

[0110] 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.

[0111] In some embodiments, the battery cell includes an outer shell, which includes a shell and an end cover, the shell having an opening, and the end cover sealing the opening. The end cover is usually welded to the shell so that the end cover and the shell are firmly connected. Since the high temperature generated by the welding of the end cover and the shell affects the performance of the end cover and the shell, the strength of the area near the weld mark of the end cover and the shell is reduced, and this area can be called a heat-affected zone. When the battery cell is in thermal runaway or the gas production inside the battery cell is too large, since the narrow surface of the battery cell is not restrained, it is easy to affect the heat-affected zone of the narrow surface, causing the heat-affected zone of the narrow surface to crack, resulting in low reliability of the battery cell.

[0112] In view of this, to address the issues of casing fatigue cracking and low battery cell reliability, an embodiment of the present application provides a technical solution. A battery cell includes a casing, which includes a shell and an end cap. The shell has an opening and includes two first walls arranged opposite each other along a first direction and two second walls arranged opposite each other along a second direction. The outer surface area of ​​the first wall is smaller than the outer surface area of ​​the second wall. The first wall includes a first opening portion and a first body portion sequentially arranged along a third direction. The third direction is parallel to the thickness direction of the end cap. The first body portion is farther away from the opening than the first opening portion. The end cap is connected to the first and second walls and closes the opening. The first wall has a dimension W1 in the second direction and a dimension W2 in the first direction, satisfying the condition 0.2≤W1 / W2≤0.5. The thickness of the first opening portion is greater than the thickness of the first body portion. The second, third, and first directions are perpendicular to each other. This technical solution improves the strength of the shell and reduces the risk of shell cracking near the weld area between the shell and the end cap, thereby enhancing the reliability of the battery cell.

[0113] In such a battery cell, the outer surface area of ​​the first wall is smaller than the outer surface area of ​​the second wall, and the first wall can serve as the narrow side of the battery cell. When the ratio of the dimension of the first wall in the second direction to the dimension of the second wall in the first direction satisfies the aforementioned relationship, the first opening is thickened to provide greater strength at the first opening, reducing the risk of cracking of the housing near the weld area between the housing and the end cap, thereby enhancing the reliability of the battery cell.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Please refer to Figure 2, which is an exploded view 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, which cover each other and together define 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-like 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.

[0121] 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.

[0122] 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.

[0123] Please refer to Figure 3, which is an exploded view 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 21a and an end cap 21b. Shell 21a has an opening, and end cap 21b seals the opening, isolating the internal environment of battery cell 20 from the external environment.

[0124] The shell 21a is a component used to cooperate with the end cap 21b 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 shell 21a and the end cap 21b can be independent components. The shell 21a can be of various shapes and sizes. Specifically, the shape of the shell 21a can be determined according to the specific shape and size of the electrode assembly 22. The material of the shell 21a can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy (such as three-series aluminum), etc.

[0125] The end cap 21b is a component that covers the opening of the housing 21a to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 21b can be adapted to the shape of the housing 21a to fit the housing 21a. Optionally, the end cap 21b can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the end cap 21b from deforming when subjected to compression or collision, thereby providing the battery cell 20 with greater structural strength and improved reliability. Functional components such as electrode terminals 23 can be provided on the end cap 21b. The electrode terminals 23 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 21b can 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 present embodiment. In some embodiments, an insulating structure can be provided on the inside of the end cap 21b to isolate the electrical connection components within the housing 21a from the end cap 21b to reduce the risk of short circuits. For example, the insulating structure may be plastic, rubber, or the like.

[0126] 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 shell 21a. 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.

[0127] Please refer to Figure 3 and further to Figures 4 to 6. Figure 4 is a perspective view of a battery cell provided in some embodiments of the present application. Figure 5 is a cross-sectional view of a housing provided in some embodiments of the present application, and Figure 5 is a cross-sectional view of the housing before assembly with an end cap. Figure 6 is a partial enlarged view of point A in Figure 5. Embodiments of the present application provide a battery cell 20, which includes a housing 21. Housing 21 includes a housing 21a and an end cap 21b. Housing 21a has an opening and includes two first walls 211 disposed opposite each other along a first direction Z and two second walls 212 disposed opposite each other along a second direction Y. The outer surface area of ​​the first wall 211 is smaller than the outer surface area of ​​the second wall 212. The first wall 211 includes a first opening portion 2111 and a first body portion 2112, which are sequentially arranged along a third direction X. The third direction X is parallel to the thickness of the end cap 21b. The first body portion 2112 is further away from the opening than the first opening portion 2111. The end cap 21b is connected to the first wall 211 and the second wall 212 to seal the opening. Among them, the dimension of the first wall 211 in the second direction Y is W1, and the dimension of the second wall 212 in the first direction Z is W2, satisfying 0.2≤W1 / W2, the maximum thickness of the first opening portion 2111 is greater than the thickness of the first main body portion 2112, and the second direction Y, the third direction X and the first direction Z are perpendicular to each other.

[0128] In the figure, the direction indicated by the letter X can be the third direction, the direction indicated by the letter Y can be the second direction, and the direction indicated by the letter Z can be the first direction. The third direction X is parallel to the thickness direction of the end cap 21b, and the third direction X can be parallel to the height direction of the battery cell 20. The second direction Y can be parallel to the width direction of the battery cell 20. The first direction Z can be parallel to the length direction of the battery cell 20.

[0129] The first wall 211 and the second wall 212 are disposed adjacent to each other. The first wall 211 and the second wall 212 may be adjacent side walls of the housing 21a. The two first walls 211 and the two second walls 212 form an opening at the same end. The end cap 21b is connected to the two first walls 211 and the two second walls 212 and closes the opening. The two first walls 211 and the two second walls 212 form a receiving cavity for accommodating the electrode assembly 22.

[0130] The outer surface area of ​​the first wall 211 refers to the area of ​​the surface of the first wall 211 facing away from the interior of the battery cell 20. The outer surface area of ​​the second wall 212 refers to the area of ​​the surface of the second wall 212 facing away from the interior of the battery cell 20. The outer surface area of ​​the first wall 211 is smaller than the outer surface area of ​​the second wall 212. The first wall 211 may be the smaller surface of the housing 21a, for example, the narrow side of the battery cell 20.

[0131] The first opening portion 2111 and the first body portion 2112 are sequentially distributed along the third direction X. The first body portion 2112 is farther away from the opening than the first opening portion 2111 , so that the first opening portion 2111 is closer to the end cover 21 b than the first body portion 2112 .

[0132] The size of the first wall 211 in the second direction Y is smaller than the size of the second wall 212 in the first direction Z, and the area of ​​the outer surface of the first wall 211 is smaller than the area of ​​the outer surface of the second wall 212, so that the size of the first wall 211 in the second direction Y can be the size of the shell 21a in the second direction Y, and the size of the second wall 212 in the first direction Z can be the size of the shell 21a in the first direction Z.

[0133] In some embodiments, the first body portion 2112 may have a uniform thickness structure, and the thickness of the first body portion 2112 may be the maximum thickness of the first body portion 2112. The first opening portion 2111 may have a uniform thickness structure or a variable thickness structure. When the first opening portion 2111 has a uniform thickness structure, the maximum thickness of the first opening portion 2111 is the thickness at any position of the first opening portion 2111. When the first opening portion 2111 has a variable thickness structure, the maximum thickness of the first opening portion 2111 may be the thickness at the position where the thickness of the first opening portion 2111 is the maximum.

[0134] Optionally, when the first opening portion 2111 is a thickened structure, the thickness of the first opening portion 2111 can gradually decrease from the end away from the first main body portion 2112 toward the end close to the first main body portion 2112, and the area with the largest thickness of the first opening portion 2111 is located at the end away from the first main body portion 2112.

[0135] According to the battery cell 20 of the embodiment of the present application, the area of ​​the outer surface of the first wall 211 is smaller than the area of ​​the outer surface of the second wall 212. The first wall 211 can be the narrow side of the battery cell 20. When the ratio of the size of the first wall 211 in the second direction Y to the size of the second wall 212 in the first direction Z satisfies the above relationship (0.2≤W1 / W2), the first opening portion 2111 is thickened so that the first opening portion 2111 has higher strength, which can reduce the risk of cracking of the shell 21a near the welding area between the shell 21a and the end cover 21b when the battery cell 20 thermally runs away or the gas production is too large, so that the battery cell 20 has higher reliability.

[0136] Optionally, W1 / W2 may be, but is not limited to, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, etc.

[0137] In some embodiments, along the thickness direction of the first wall 211 , the first body portion 2112 has a first surface facing the interior of the battery cell 20 , and a portion of the first opening portion 2111 may protrude from the first surface.

[0138] In some embodiments, along the thickness direction of the first wall 211 , the first body portion 2112 has a second surface facing away from the interior of the battery cell 20 , and a portion of the first opening 2111 may protrude from the second surface.

[0139] In some embodiments, along the thickness direction of the first wall 211, the first main body portion 2112 has a first surface facing the interior of the battery cell 20 and a second surface away from the interior of the battery cell 20, and part of the first opening portion 2111 can protrude from the first surface, and part of the first opening portion 2111 can protrude from the second surface.

[0140] In some embodiments, the first opening portion 2111 can be provided separately or integrally. For example, during the manufacturing process of the housing 21a, a thickened portion is provided separately from the base of the first wall 211 at the opening of the first wall 211, and the thickened portion is fixedly connected to the base to form the first opening portion 2111. The base forms the first body portion 2112 in the area of ​​the first wall 211 located in the first body portion 2112. For another example, during the manufacturing process of the housing 21a, the housing 21a is an integrally formed structure, and the housing 21a can be stamped to form the first opening portion 2111 at the opening of the first wall 211. The maximum thickness of the first opening portion 2111 is greater than the thickness of the first body portion 2112.

[0141] In some embodiments, due to the thickness difference between the first opening 2111 and the first body 2112, when a portion of the first opening 2111 protrudes from the first surface, a groove is formed between the first opening 2111 and the first surface of the first body 2112. The body 221 of the electrode assembly 22 can be disposed within the groove, or the body 221 can be located outside the groove. It should be noted that the groove is a concave area formed by the height difference between the first opening and the first body.

[0142] According to some embodiments of the present application, W1 / W2≤0.6.

[0143] In the above solution, when the ratio of the dimension of the first wall 211 in the second direction Y to the dimension of the second wall 212 in the first direction Z satisfies the above relationship, the risk of cracking of the housing 21a near the weld area between the housing 21a and the end cap 21b can be reduced while ensuring that the first opening 2111 has a high strength. According to some embodiments of the present application, 0.25≤W1 / W2≤0.35.

[0144] Optionally, W1 / W2 may be, but is not limited to, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, etc.

[0145] In the above solution, compared with 0.2≤W1 / W2, when 0.25≤W1 / W2≤0.35, the thickening treatment of the first opening portion 2111 can effectively reduce the risk of cracking of the shell 21a near the welding area between the shell 21a and the end cover 21b, improve the manufacturability of the shell, and further improve the reliability of the battery cell 20.

[0146] According to some embodiments of the present application, 50 mm ≤ W1 ≤ 90 mm, optionally, 60 mm ≤ W1 ≤ 86 mm.

[0147] Optionally, W1 can be but not limited to 50mm, 52mm, 54mm, 56mm, 58mm, 60mm, 62mm, 64mm, 66mm, 68mm, 70mm, 72mm, 74mm, 76mm, 78mm, 80mm, 82mm, 84mm, 86mm, 88mm, 90mm, etc.

[0148] In the above solution, when the dimensions of the first wall 211 in the second direction Y satisfy the above relationship (50mm≤W1≤90mm), the first opening 2111 is thickened. This, on the one hand, can improve the strength of the first opening 2111 and reduce the risk of cracking of the shell 21a near the weld area between the shell 21a and the end cap 21b. On the other hand, it can facilitate processing and manufacturing. Compared to 50mm≤W1≤90mm, when 60mm≤W1≤86mm, the thickening of the first opening 2111 can reduce the risk of cracking of the shell 21a near the weld area between the shell 21a and the end cap 21b, and reduce the difficulty of processing and manufacturing.

[0149] According to some embodiments of the present application, the maximum thickness of the first opening portion 2111 is h1, and the thickness of the first body portion 2112 is h2, satisfying 0.55≤h / W≤2.5, h=(h1-h2) / h2, and W=W1 / W2.

[0150] h may be a thickness ratio of the first opening portion 2111 relative to the first body portion 2112 , and W may be a ratio of a dimension of the first wall 211 in the second direction Y to a dimension of the second wall 212 in the first direction Z.

[0151] If h is too large, the first opening 2111 occupies a larger space, affecting the energy density of the battery cell 20, and the shell 21a is too difficult to manufacture; if W is too small, the shell 21a is prone to cracking at the second wall 212, and thickening the first wall 211 has a poor effect on improving the cracking of the shell 21a.

[0152] If W is too large or h is too small, the shell 21a is subjected to excessive expansion force, the thickness of the first opening 2111 is small, the strength of the first wall 211 is insufficient, and the first wall 211 is prone to cracking.

[0153] In the above scheme, the maximum thickness of the first opening portion 2111, the thickness of the first main body portion 2112, the size of the first wall 211 in the second direction Y, and the size of the second wall 212 in the first direction Z satisfy the above relationship. The first opening portion 2111 is thickened so that the first opening portion 2111 has higher strength, which can reduce the risk of cracking of the shell 21a near the welding area between the shell 21a and the end cover 21b, and facilitates the processing and manufacturing of the first opening portion 2111. The first opening portion 2111 occupies less space, and the battery cell 20 has a higher energy density.

[0154] h / W may be any value between 0.55 and 2.5. Alternatively, h / W may be, but is not limited to, 0.55, 0.65, 0.75, 0.85, 0.95, 1.05, 1.15, 1.25, 1.35, 1.45, 1.55, 1.65, 1.75, 1.85, 1.95, 2.05, 2.15, 2.25, 2.35, 245, 25, etc.

[0155] According to some embodiments of the present application, W2 satisfies: 83 mm ≤ W2 ≤ 450 mm.

[0156] Optionally, W2 can be but is not limited to 83mm, 85mm, 90mm, 95mm, 100mm, 120mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, 410mm, 420mm, 430mm, 440mm, 450mm, etc.

[0157] According to some embodiments of the present application, 0.6≤h / W≤1.8.

[0158] Alternatively, h / W may be, but is not limited to, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, etc.

[0159] In the above solution, compared with 0.55≤h / W≤2.5, when 0.6≤h / W≤1.8, the first opening 2111 occupies a smaller space, the processing and manufacturing difficulty of the first opening 2111 is lower, and the first opening 2111 has higher strength.

[0160] According to some embodiments of the present application, the maximum thickness of the first opening portion 2111 is h1, the thickness of the first body portion 2112 is h2, and the area of ​​the outer surface of the first wall 211 is S, which satisfies (1 / 360000) mm -2 ≤h / S≤(1 / 9000)mm -2 , h=(h1-h2) / h2.

[0161] The area S of the outer surface of the first wall 211 is the product of the dimension of the housing 21 a in the second direction Y and the dimension of the first wall 211 in the third direction X.

[0162] In the above solution, the maximum thickness of the first opening 2111, the thickness of the first body 2112, and the area of ​​the outer surface of the first wall 211 satisfy the above relationship ((1 / 360000) mm -2 ≤h / S≤(1 / 9000)mm -2 , h=(h1-h2) / h2), which is convenient for processing and manufacturing. The first opening portion 2111 has high strength, which can reduce the risk of cracking of the shell 21a near the welding area of ​​the shell 21a and the end cover 21b. In addition, the first opening portion 2111 occupies a smaller space, and the battery cell 20 has a higher energy density.

[0163] h / S can be (1 / 360000) mm -2 and (1 / 9000) mm -2 Alternatively, h / S may be, but is not limited to, (1 / 360000) mm. -2 、(1 / 300000)mm -2 、(1 / 250000)mm -2 、(1 / 200000)mm -2 、(1 / 150000)mm -2 、(1 / 100000)mm -2 、(1 / 50000)mm -2 、(1 / 10000)mm -2 、(1 / 9000)mm -2 wait.

[0164] According to some embodiments of the present application, (1 / 300000) mm -2 ≤h / S≤(1 / 15000)mm -2 .

[0165] In the above scheme, compared with (1 / 360000) mm -2 ≤h / S≤(1 / 9000)mm -2 , when (1 / 300000) mm -2≤h / S≤(1 / 15000)mm -2 When the first opening 2111 is formed, the processing and manufacturing difficulty is low, the first opening 2111 has high strength, and the space occupied by the first opening 2111 is small.

[0166] Alternatively, h / S may be, but is not limited to, (1 / 300000) mm -2 、(1 / 200000)mm -2 、(1 / 100000)mm -2 、(1 / 50000)mm -2 、(1 / 40000)mm -2 、(1 / 30000)mm -2 、(1 / 20000)mm -2 、(1 / 15000)mm -2 wait.

[0167] According to some embodiments of the present application, (1 / 240000) mm -2 ≤h / S≤(1 / 22500)mm -2 .

[0168] According to some embodiments of the present application, 4500mm 2 ≤S≤36000mm 2 .

[0169] Optionally, S can be but is not limited to 4500 mm 2 , 5000mm 2 , 6000mm 2 , 10000mm 2 , 20000mm 2 、30000mm 2 、36000mm 2 wait.

[0170] In the above scheme, the area of ​​the outer surface of the first wall 211 satisfies the above relationship, the battery cell 20 has a higher energy density, which facilitates the processing and manufacturing of the first wall 211, and the first opening portion 2111 has higher strength, reducing the risk of cracking of the shell 21a near the welding area between the shell 21a and the end cover 21b.

[0171] According to some embodiments of the present application, 6000mm 2 ≤S≤22500mm 2 .

[0172] Optionally, S can be but is not limited to 6000 mm 2 、6500mm 2 , 7000mm 2 , 7500mm2 , 8000mm 2 , 9000mm 2 , 10000mm 2 、11000mm 2 , 12000mm 2 、13000mm 2 、14000mm 2 , 15000mm 2 、16000mm 2 、17000mm 2 、18000mm 2 、19000mm 2 , 20000mm 2 , 21000mm 2 , 21500mm 2 , 22000mm 2 , 22500mm 2 wait.

[0173] In the above scheme, compared with 4500mm 2 ≤S≤36000mm 2 , when 6000mm 2 ≤S≤22500mm 2 When the battery cell 20 has a higher energy density, the first opening portion 2111 has a higher strength, reducing the risk of the shell 21a cracking near the welding area between the shell 21a and the end cover 21b.

[0174] According to some embodiments of the present application, h1 and h2 satisfy at least one of the following conditions: (1) 0.1≤h≤0.5; (2) 0.55mm≤h1≤1.8mm; (3) 0.5mm≤h2≤1.2mm.

[0175] Alternatively, h may be, but is not limited to, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.48, 0.5, etc.

[0176] Alternatively, h1 may be, but is not limited to, 0.55, 0.69, 0.84, 1, 1.17, 1.35, 1.54, 1.7, 1.8, etc.

[0177] Alternatively, h2 can be, but is not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.15, 1.2, etc.

[0178] In the above solution, the maximum thickness of the first opening portion 2111 and the thickness of the first main body portion 2112 satisfy the above relationship, which is convenient for processing and manufacturing. The first opening portion 2111 has higher strength, occupies less space, and the battery cell 20 has higher energy density.

[0179] According to some embodiments of the present application, h1 and h2 satisfy at least one of the following conditions: (1) 0.15≤h≤0.3; (2) 0.69mm≤h1≤1.04mm; (3) 0.6mm≤h2≤0.8mm.

[0180] Alternatively, h may be, but is not limited to, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.3, etc.

[0181] Alternatively, h1 may be, but is not limited to, 0.69 mm, 0.75 mm, 0.79 mm, 0.82 mm, 0.9 mm, 0.94 mm, 1.04 mm, etc.

[0182] Alternatively, h2 may be, but is not limited to, 0.6 mm, 0.64 mm, 0.66 mm, 0.68 mm, 0.7 mm, 0.72 mm, 0.74 mm, 0.8 mm, etc.

[0183] In the above scheme, compared with 0.1≤h≤0.5, 0.55mm≤h1≤1.8mm, 0.5mm≤h2≤1.2mm, when 0.15≤h≤0.3, 0.69mm≤h1≤1.56mm, 0.6mm≤h2≤0.8mm, the processing and manufacturing difficulty is lower, the strength of the first opening portion 2111 is higher, and the space occupied by the first opening portion 2111 is smaller.

[0184] Please refer to Figure 7, which is a schematic diagram of the structure of the first wall provided in some embodiments of the present application. Figure 7 is a schematic diagram of the structure of the first wall before the shell and the end cover are assembled. According to some embodiments of the present application, the first opening portion 2111 includes a first section 2111a and a second section 2111b connected to each other, the first section 2111a, the second section 2111b and the first body portion 2112 are distributed in sequence along the third direction X, the maximum thickness of the second section 2111b is greater than the thickness of the first body portion 2112, the maximum thickness of the second section 2111b is greater than the maximum thickness of the first section 2111a, a first step surface 2113 is formed between the second section 2111b and the first section 2111a, and the end cover 21b is overlapped on the first step surface 2113 and connected to the first section 2111a.

[0185] The first section 2111a, the second section 2111b and the first body portion 2112 are sequentially distributed along the third direction X. The first section 2111a is closer to the opening than the second section 2111b. The first section 2111a is used to connect with the end cover 21b.

[0186] The maximum thickness of the first section 2111a can be h3, and the maximum thickness of the second section 2111b can be h1, satisfying h1>h3, that is, the maximum thickness of the second section 2111b is greater than the maximum thickness of the first section 2111a, so that after the end cover 21b is connected to the first section 2111a, the first opening portion 2111 has higher strength.

[0187] In some embodiments, 0.4 mm ≤ h3 ≤ 1.6 mm.

[0188] Optionally, h3 can be but is not limited to 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, etc.

[0189] Because the first wall 211 is the narrow side of the battery cell 20, during the manufacturing process of the battery cell 20, the housing 21a is typically thinned in the area of ​​the first section 2111a to ensure that the maximum thickness of this area is less than the thickness of the first body portion 2112. This facilitates welding of the first wall 211 to the end cap 21b. In some embodiments of the present application, before the first section 2111a is connected to the end cap 21b, the housing 21a may be thickened in the area of ​​the first section 2111a to ensure that the maximum thickness of the housing 21a in the area of ​​the first section 2111a is greater than or equal to the thickness of the first body portion 2112, thereby improving the connection security between the first wall 211 and the end cap 21b. In other embodiments of the present application, before the first section 2111a is connected to the end cover 21b, the area of ​​the shell 21a in the first section 2111a can be thickened, and the maximum thickness of the area of ​​the shell 21a in the first section 2111a can be less than the thickness of the first main body 2112 to improve the connection firmness between the first wall 211 and the end cover 21b.

[0190] The second section 2111b is disposed adjacent to the first section 2111a, and at least a portion of the second section 2111b is a heat-affected zone after the end cover 21b is welded to the first section 2111a.

[0191] The maximum thickness of the second section 2111b is greater than the maximum thickness of the first section 2111a. A first step surface 2113 is formed between the second section 2111b and the first section 2111a. During the manufacturing process of the battery cell 20, the end cover 21b can overlap the first step surface 2113 to facilitate the positioning of the end cover 21b.

[0192] In the above scheme, the first section 2111a, the second section 2111b and the first main body 2112 are distributed in sequence along the third direction X, and the end cover 21b is connected to the first section 2111a, so that the second section 2111b is adjacent to the connection part between the end cover 21b and the first section 2111a. The first opening 2111 has high strength, which can reduce the risk of cracking of the shell 21a near the welding area between the shell 21a and the end cover 21b, thereby improving the service life and reliability of the battery cell 20.

[0193] Please refer to Figure 8, which is a schematic diagram of the structure of the second wall provided in some embodiments of the present application. According to some embodiments of the present application, the second wall 212 includes a second opening portion 2121 and a second body portion 2122 sequentially connected in the third direction X. The second body portion 2122 is farther away from the second opening portion 2121. The second opening portion 2121 is connected to the end cap 21b. The maximum thickness of the second opening portion 2121 is greater than the thickness of the second body portion 2122.

[0194] Along the third direction X, the second body portion 2122 is farther away from the second opening portion 2121 , and the second opening portion 2121 may be surrounded to form an opening.

[0195] In some embodiments, the end cap 21 b may be welded to a portion of the second opening portion 2121 to form a second welding zone, which may be referred to as a weld mark.

[0196] In some embodiments, the second body portion 2122 may have a uniform thickness structure, and the thickness of the second body portion 2122 may be the maximum thickness of the second body portion 2122. The second opening portion 2121 may have a uniform thickness structure or a variable thickness structure. When the second opening portion 2121 has a uniform thickness structure, the maximum thickness of the second opening portion 2121 is the thickness at any position of the second opening portion 2121. When the second opening portion 2121 has a variable thickness structure, the maximum thickness of the second opening portion 2121 may be the thickness at the position where the second opening portion 2121 has the maximum thickness.

[0197] Optionally, when the second opening portion 2121 is a thickened structure, the thickness of the second opening portion 2121 can gradually decrease from the end away from the second main body portion 2122 toward the end close to the second main body portion 2122, and the area with the largest thickness of the second opening portion 2121 is located at the end away from the second main body portion 2122.

[0198] In the above solution, the second opening portion 2121 is thickened to increase the strength of the second wall 212. During the charge and discharge cycle of the battery cell 20, the increased strength of the second opening portion 2121 can reduce the risk of cracking of the shell 21a near the welding area between the shell 21a and the end cover 21b.

[0199] In some embodiments, when viewed along the thickness direction of the end cover 21 b , the second opening 2121 may partially overlap with the electrode assembly 22 , or the second opening 2121 may not overlap with the electrode assembly 22 .

[0200] According to some embodiments of the present application, the shell 21a may further include a bottom wall 213, two first walls 211 and two second walls 212 are arranged around the bottom wall 213, the two first walls 211 and the two second walls 212 are integrally formed with the bottom wall 213, and the bottom wall 213 and the end cover 21b are arranged opposite to each other in the third direction X.

[0201] According to some embodiments of the present application, the shell 21a is a prismatic structure with openings at both ends, and there are two end covers 21b, which respectively close the two openings.

[0202] When the housing 21 a has a prismatic structure, the battery cell 20 may be a square battery.

[0203] When the positive electrode tab and the negative electrode tab are arranged at both ends of the electrode assembly 22, the shell 21a has two openings, and the positive electrode terminal and the negative electrode terminal can be respectively arranged on the two end covers 21b so as to be electrically connected to the positive electrode tab and the negative electrode tab respectively, so as to facilitate the charging and discharging of the battery cell 20.

[0204] In the above solution, openings are respectively provided at both ends of the shell 21 a , and both openings are thickened to reduce the risk of cracking of the shell 21 a .

[0205] According to some embodiments of the present application, the battery cell 20 also includes an electrode assembly 22, the electrode assembly 22 includes a positive electrode plate, the positive electrode plate includes a positive electrode active material, the positive electrode active material includes a nickel-containing compound, the nickel-containing compound includes a layered lithium-containing transition metal oxide, and the ratio of the molar amount of the nickel element in the layered lithium-containing transition metal oxide to the total molar amount of the transition metal element in the layered lithium-containing transition metal oxide is not less than 50%.

[0206] The content of nickel affects the energy density of the battery cell 20 . The greater the content of nickel, the higher the energy density of the battery cell 20 .

[0207] In the above scheme, the nickel content is high, the battery cell 20 has a high energy density, and the first opening portion 2111 is thicker and has higher strength, which can reduce the risk of the shell 21a of the battery cell 20 with a high nickel content cracking near the welding area between the shell 21a and the end cover 21b.

[0208] According to some embodiments of the present application, the layered lithium-containing transition metal oxide includes Li a Ni b Coc M d O e A f , wherein, 0<a≤1.2, 0.6≤b<1, 0<c<1; 0<d<1; 1≤e≤2; 0≤f≤1; M includes but is not limited to one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B; A includes but is not limited to one or more of N, F, S and Cl.

[0209] In the above solution, the nickel content is high, the energy density of the battery cell 20 is high, and the first opening portion 2111 has high strength, reducing the risk of cracking of the shell 21a of the battery cell 20 with a high nickel content near the welding area between the shell 21a and the end cover 21b.

[0210] According to some embodiments of the present application, 0.7≤b≤0.98.

[0211] Optionally, b can be a point but not limited to 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, 0.92, 0.94, 0.96, 0.98, etc.

[0212] In the above solution, the nickel content is high, and the battery cell 20 has a high energy density.

[0213] According to some embodiments of the present application, 0.4≤b / h≤8.1.

[0214] Alternatively, b / h may be, but is not limited to, 0.4, 1.1, 1.8, 2.5, 3.2, 3.9, 4.6, 5, 5.7, 6.4, 7.1, 7.8, 8.1, etc.

[0215] In the above solution, the battery cell 20 is easy to manufacture, has a high energy density, produces less gas due to thermal runaway, has a high strength, and has a low risk of fatigue cracking of the first wall 211.

[0216] According to some embodiments of the present application, 1≤b / h≤6.

[0217] Alternatively, b / h may be, but is not limited to, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, etc.

[0218] In the above solution, compared with 0.4≤b / h≤8.1, when 1≤b / h≤6, the strength of the first wall 211 is higher and the space occupied by the first opening is smaller; the battery cell 20 has a higher energy density, and the battery cell 20 produces less gas due to thermal runaway.

[0219] Referring to FIG. 3 , according to some embodiments of the present application, the electrode assembly 22 includes a main body 221 , which is provided with an active material. The main body 221 has a first surface 221 a facing the end cap 21 b. The first opening 2111 extends beyond the first surface 221 a along the direction from the first main body 2112 to the first opening 2111 .

[0220] In some embodiments, the electrode assembly 22 further includes a tab 222 extending from the main body 221 . The tab 222 may extend from the first surface 221 a .

[0221] When viewed along the thickness direction of the first wall 211 , the first opening 2111 does not overlap with the main body 221 .

[0222] In the above solution, along the direction from the first body portion 2112 to the first opening portion 2111 , the first opening portion 2111 exceeds the first surface 221 a , which can reduce the risk of interference between the first opening portion 2111 and the body portion 221 .

[0223] According to some embodiments of the present application, along the direction from the second body portion 2122 to the second opening portion 2121 , the second opening portion 2121 exceeds the first surface 221 a .

[0224] When viewed along the thickness direction of the first wall 211 , the second opening 2121 does not overlap with the main body 221 .

[0225] In the above solution, along the direction from the second body portion 2122 to the second opening portion 2121 , the second opening portion 2121 extends beyond the first surface 221 a , which can reduce the risk of interference between the second opening portion 2121 and the body portion 221 .

[0226] Please refer to Figure 9, which is a cross-sectional view of a portion of the assembled end cap and housing according to some embodiments of the present application. According to some embodiments of the present application, the housing 21a and the end cap 21b are welded to form a weld region 210. The average grain size of the first opening 2111, excluding the weld region 210, is greater than the average grain size of the first body 2112. The average grain size is the average grain size of the grains along the thickness direction of the first wall 211.

[0227] The welding area 210 is an area formed by welding the shell 21 a and the end cover 21 b . In some embodiments, the welding area 210 may be referred to as a weld mark.

[0228] The thickness direction of the first wall 211 may be parallel to the Z direction.

[0229] The test method standard reference for average grain size is: GB / T6394-2017 "Method for determination of average grain size of metals" and GB / T 13298-2017 "Metallic material grain size determination by electron rearview microscope method".

[0230] In the above scheme, the average grain size of the first opening portion 2111 other than the welding area 210 is greater than the average grain size of the first main body portion 2112, which is beneficial to enhancing the strength of the first opening portion 2111, so that the first opening portion 2111 has higher strength, and reduces the risk of cracking of the shell 21a near the welding area 210 of the shell 21a and the end cover 21b.

[0231] According to some embodiments of the present application, in a cross-section of the first wall 211 parallel to the thickness direction of the first wall 211 , the number of grains in the portion of the first opening 2111 located below the welding area 210 in the width direction of the cross-section is greater than or equal to 15.

[0232] The width direction of the cross section may be parallel to the Z direction.

[0233] "The portion of the first opening portion 2111 located below the welding area 210" refers to the portion of the first opening portion 2111 located below the welding area 210 in the direction in which the first opening portion 2111 points to the first main body portion 2112 in the X direction in Figure 9, that is, the portion of the first opening portion 2111 located away from the welding area 210 along the direction in which the first opening portion 2111 points to the first main body portion 2112.

[0234] In the above solution, in the width direction of the cross section, the number of grains is greater than or equal to 15, which is beneficial to enhancing the strength of the first opening portion 2111, so that the first opening portion 2111 has higher strength.

[0235] According to some embodiments of the present application, the average grain size of the first opening portion 2111 excluding the welding region 210 is in a range of 70 μm to 1200 μm; and / or the average grain size of the first body portion 2112 is in a range of 30 μm to 1000 μm.

[0236] Optionally, the average grain size of the first opening portion 2111 excluding the welding area 210 may be, but is not limited to, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, etc.

[0237] Optionally, the average grain size of the first body portion 2112 may be, but is not limited to, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, etc.

[0238] In the above solution, the average grain size of the first opening portion 2111 and / or the average grain size of the first body portion 2112 satisfies the above relationship, which is beneficial to enhancing the strength of the first opening portion 2111, so that the first opening portion 2111 has higher strength.

[0239] According to some embodiments of the present application, the average grain size of the second opening portion 2121 excluding the welding region 210 is larger than the average grain size of the second body portion 2122 , where the average grain size is the average grain size of the grains in the thickness direction of the second wall 212 .

[0240] In the above scheme, the average grain size of the second opening portion 2121 except the welding area 210 is larger than the average grain size of the second main body portion 2122, which is beneficial to enhancing the strength of the second opening portion 2121, so that the second opening portion 2121 has higher strength, and reduces the risk of cracking of the shell 21a near the welding area 210 of the shell 21a and the end cover 21b.

[0241] According to some embodiments of the present application, in a cross-section of the second wall 212 parallel to the thickness direction of the second wall 212 , the number of grains in the portion of the second opening 2121 located below the welding area 210 is greater than or equal to 15 in the width direction of the cross-section.

[0242] The width direction of the cross section is parallel to the Y direction.

[0243] "The portion of the second opening portion 2121 located below the welding area 210" refers to the portion of the second opening portion 2121 located below the welding area 210 in the direction in which the second opening portion 2121 points to the second main body portion 2122 in the X direction, that is, the portion of the second opening portion 2121 located away from the welding area 210 along the direction in which the second opening portion 2121 points to the second main body portion 2122.

[0244] In the above solution, in the width direction of the cross section, the number of grains is greater than or equal to 15, which is beneficial to enhancing the strength of the second opening portion 2121, so that the second opening portion 2121 has higher strength.

[0245] According to some embodiments of the present application, the average grain size of the second opening portion 2121 excluding the welding region 210 is in a range of 70 μm to 1200 μm; and / or the average grain size of the second body portion 2122 is in a range of 30 μm to 1000 μm.

[0246] Optionally, the average grain size of the second opening portion 2121 excluding the welding area 210 may be, but is not limited to, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, etc.

[0247] Optionally, the average grain size of the second body portion 2122 may be, but is not limited to, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, etc.

[0248] In the above solution, the average grain size of the second opening portion 2121 and / or the average grain size of the second body portion 2122 satisfies the above relationship, which is beneficial to enhancing the strength of the second opening portion 2121, so that the second opening portion 2121 has higher strength.

[0249] The structure and test data of the battery cell 20 are introduced below with a specific embodiment:

[0250] Example 1

[0251] During the preparation of the battery cell 20, the end cap 21b and the housing 21a are laser welded. The housing 21a is made of aluminum. The length of the battery cell 20 (the dimension W2 of the housing 21a in the first direction Z) is 220 mm, and the width of the battery cell 20 (the dimension W1 of the housing 21a in the second direction Y) is 44 mm. W is 0.2, the thickness h2 of the first body 2112 is 0.5 mm, the thickening ratio h of the first opening 2111 is 0.15, the h / W ratio is 0.75, and the nickel content b is 0.95, with a b / h ratio of 6.3.

[0252] Example 2

[0253] Compared with Example 1, h is 0.2 and h / W is 1.

[0254] Example 3

[0255] Compared with Example 1, h is 0.5 and h / W is 2.5.

[0256] Example 4

[0257] Compared with Example 1, the width of the battery cell 20 is 55 mm, W is 0.25, h is 0.3, and h / W is 1.2.

[0258] Example 5

[0259] Compared with Example 1, the width of the battery cell 20 is 77 mm, W is 0.35, h is 0.275, and h / W is 0.79.

[0260] Example 6

[0261] Compared with Example 1, the width of the battery cell 20 is 90 mm, the length of the battery cell 20 is 180 mm, W is 0.5, h is 0.275, and h / W is 0.55.

[0262] Example 7

[0263] Compared with Example 1, the width of the battery cell 20 is 70 mm, the length of the battery cell 20 is 148 mm, W is 0.47, h is 0.5, and h / W is 1.06.

[0264] Example 8

[0265] Compared with Example 1, the width of the battery cell 20 is 70 mm, the length of the battery cell 20 is 148 mm, W is 0.47, h is 0.25, and h / W is 0.53.

[0266] Example 9

[0267] Compared with Example 1, the width of the battery cell 20 is 88.5 mm, the length of the battery cell 20 is 148 mm, W is 0.6, h is 0.35, and h / W is 0.58.

[0268] Comparative Example 1

[0269] Compared with Example 1, the width of the battery cell 20 is 33 mm, the length of the battery cell 20 is 220 mm, W is 0.15, h is 0.15, and h / W is 1.

[0270] Comparative Example 2

[0271] Compared with Example 1, the width of the battery cell 20 is 44 mm, the length of the battery cell 20 is 220 mm, W is 0.2, h is 0.1, and h / W is 0.5.

[0272] Comparative Example 3

[0273] Compared with Example 1, the width of the battery cell 20 is 70 mm, the length of the battery cell 20 is 148 mm, W is 0.47, h is 0.2, and h / W is 0.42.

[0274] The battery cells 20 in Examples 1-8 and Comparative Examples 1-3 were subjected to short-circuit tests. The test method was as follows with reference to GBT31485-2015. The test results are shown in Table 1.

[0275] The battery cells 20 are charged at a constant current of 1I1(A) to the charging termination voltage specified in the enterprise's technical conditions in an environment with a temperature of 25°C±5°C, a relative humidity of 15% to 90%, and an atmospheric pressure of 86kPa to 106kPa. The battery cells 20 are then switched to constant voltage charging and charging is stopped when the charging current drops to 0.05I1(A). The battery cells 20 are then left standing for 1 hour. A short-circuit test is performed on the battery cells 20. The short-circuit method is as follows: the positive and negative electrodes of the battery cells 20 are externally short-circuited. The external circuit resistance should be less than 5mΩ. Thermal runaway occurs in the battery cells 20. The integrity of the housing 21a of the battery cells 20 in the thermal runaway state is observed.

[0276] Table 1

[0277] From the comparison of the results of Examples 1-8 and Comparative Example 1 in Table 1, it can be seen that when W is too small, the second wall 212 of the shell 21a is prone to cracking.

[0278] From the comparison of the results of Examples 1-8 and Comparative Examples 2-3 in Table 1, it can be seen that when h / W is too small, the first wall 211 of the shell 21a is prone to cracking. If the first opening 2111 of the first wall 211 is thickened, the risk of cracking of the first wall 211 can be reduced, and the risk of cracking of the shell 21a can be reduced.

[0279] According to some embodiments of the present application, an embodiment of the present application provides a battery 100, which includes a battery cell 20 provided in any of the above embodiments.

[0280] Please refer to Figures 10 and 11. Figure 10 is a schematic diagram of the assembly of an end plate and multiple battery cells according to some embodiments of the present application, and Figure 11 is a schematic diagram of the assembly of an end plate and a battery cell at an end according to some embodiments of the present application. According to some embodiments of the present application, there are multiple battery cells 20, and the multiple battery cells 20 are stacked along the second direction Y. The battery 100 also includes an end plate 30, which is disposed at the end of the multiple battery cells 20 along the second direction Y.

[0281] In some embodiments, along the direction from the first body portion 2112 to the first opening portion 2111 , at least a portion of the first opening portion 2111 exceeds the end plate 30 .

[0282] Multiple battery cells 20 are stacked along the second direction Y. Along the second direction Y, the end plate 30 is arranged at the end of the multiple battery cells 20. The end plate 30 is connected to the battery cell 20 at the end of the multiple battery cells 20 in the second direction Y. The end plate 30 can limit the battery cell 20 at the end and restrain the deformation of the battery cell 20.

[0283] In the above solution, the end plate 30 is arranged at the end of multiple battery cells 20 in the second direction Y. The end plate 30 has a large connection area with the shell 21a of the adjacent battery cell 20 to form a constraint on the shell 21a and reduce the risk of fatigue cracking of the shell 21a.

[0284] According to some embodiments of the present application, the end plate 30 is disposed facing the second wall 212 .

[0285] In the above solution, the end plate 30 is arranged facing the second wall 212, and the end plate 30 has a large connection area with the second wall 212. During the charge and discharge cycle of the battery cell 20, the end plate 30 can constrain the second wall 212 to reduce the risk of cracking of the shell 21a near the welding area of ​​the shell 21a and the end cover 21b.

[0286] According to some embodiments of the present application, an electrical device is provided, which includes a battery cell 20 or a battery as provided in any of the above embodiments.

[0287] 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.

[0288] According to some embodiments of the present application, an energy storage device is provided. The energy storage device includes a battery cell 20 or a battery 100 as provided in any of the above embodiments.

[0289] According to some embodiments of the present application, referring to Figures 3 to 8 , a battery cell 20 is provided. The battery cell 20 is in the form of a rectangular parallelepiped. The battery cell 20 includes a housing 21, an electrode assembly 22, and an electrode terminal 23. The electrode assembly 22 is disposed within the housing 21. The housing 21 includes a shell 21a and an end cap 21b. The electrode terminal 23 is disposed on the end cap 21b and is connected to a tab of the electrode assembly 22. The housing 21a has an opening and includes two first walls 211 disposed opposite each other along a first direction Z, two second walls 212 disposed opposite each other along a second direction Y, and a bottom wall 213. The two first walls 211 and the two second walls 212 surround the bottom wall 213 and are integrally formed with the bottom wall 213. The bottom wall 213 and the end cap 21b are disposed opposite each other in a third direction X. The end cap 21b is connected to the first wall 211 and the second wall 212 to seal the opening.

[0290] The outer surface area of ​​the first wall 211 is smaller than the outer surface area of ​​the second wall 212. The first wall 211 includes a first opening portion 2111 and a first body portion 2112, which are sequentially distributed along a third direction X. The third direction X is parallel to the thickness direction of the end cap 21b. The first body portion 2112 is farther from the opening than the first opening portion 2111. The end cap 21b is connected to the first and second walls 211 and 212 to seal the opening. The dimension of the first wall 211 in the second direction Y is W1, and the dimension of the second wall 212 in the first direction Z is W2, satisfying 0.2≤W1 / W2≤0.5. The maximum thickness of the first opening portion 2111 is greater than the thickness of the first body portion 2112. The maximum thickness of the first opening portion 2111 is h1, and the thickness of the first body portion 2112 is h2, satisfying 0.55≤h / W≤2.5, h=(h1-h2) / h2, and W=W1 / W2. The maximum thickness of the first opening portion 2111 is h1, and the thickness of the first body portion 2112 is h2.

[0291] According to the battery cell 20 of the embodiment of the present application, the maximum thickness of the first opening portion 2111, the thickness of the first main body portion 2112, the dimension of the first wall 211 in the second direction Y, the dimension of the second wall 212 in the first direction Z, and the area of ​​the outer surface of the first wall 211 satisfy the above-mentioned relationship. The first opening portion 2111 is thickened, and the first opening portion 2111 has high strength, which can reduce the risk of fatigue cracking of the first wall 211 during the charge and discharge cycle of the battery cell 20. In addition, the first opening portion 2111 is easy to process and manufacture, the first opening portion 2111 occupies a small space, and the battery cell 20 has a high energy density.

[0292] 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 including a housing body and an end cap, the housing body having an opening, the housing body including two first walls oppositely disposed in a first direction and two second walls oppositely disposed in a second direction, an outer surface area of the first wall being smaller than an outer surface area of the second wall, the first wall including a first opening portion and a first body portion sequentially distributed in a third direction, the third direction being parallel to a thickness direction of the end cap, the first body portion being farther from the opening than the first opening portion, the end cap being connected to the first wall and the second wall and closing the opening; Wherein, the dimension of the first wall in the second direction is W 1 , and the dimension of the second wall in the first direction is W 2 , satisfying 0.2 ≤ W 1 / W 2 , the maximum thickness of the first opening is greater than the thickness of the first body portion, and the second direction, the third direction and the first direction are perpendicular to each other in pairs.

2. The battery cell according to claim 1, wherein, W 1 / W 2 ≤0.

6.

3. The battery cell according to claim 1 or 2, wherein, 0.25 ≤ W 1 / W 2 ≤ 0.35。 4. The battery cell according to claim 3, wherein, 50mm ≤ W 1 ≤ 90mm, optionally, 60mm ≤ W 1 ≤ 86mm.

5. The battery cell according to any one of claims 1-4, wherein, The maximum thickness of the first opening part is h1, and the thickness of the first body part is h 2 , satisfying 0.55 ≤ h / W ≤ 2.5, h = (h 1 -h 2 ) / h 2 , W = W 1 / W 2 .

6. The battery cell according to claim 5, wherein, 0.6 ≤ h / W ≤ 1.

8.

7. The battery cell according to any one of claims 1-6, wherein, The maximum thickness of the first opening is h 1 , the thickness of the first body portion is h 2 , the area of the outer surface of the first wall is S, satisfying, (1 / 360000) mm -2 ≤ h / S ≤ (1 / 9000) mm -2 , h = (h 1 - h 2 ) / h 2 .

8. The battery cell according to claim 7, wherein, (1 / 300000) mm -2 ≤ h / S ≤ (1 / 15000) mm -2 .

9. The battery cell according to claim 7 or 8, wherein, 4500mm 2 ≤S≤36000mm 2 。 10. The battery cell according to claim 9, wherein, 6000mm 2 ≤S≤22500mm 2 。 11. The battery cell according to any one of claims 1-10, wherein, The maximum thickness of the first opening part is h 1 , the thickness of the first body part is h 2 , h = (h 1 - h 2 ) / h 2 , h 1 , h 2 satisfy at least one of the following conditions: (1)0.1≤h≤0.5； (2) 0.55 mm ≤ h 1 ≤ 1.8 mm; (3) 0.5 mm ≤ h 2 ≤ 1.2 mm.

12. The battery cell according to claim 11, wherein, h 1 、h 2 satisfy at least one of the following conditions: (1)0.15≤h≤0.3； (2) 0.69 mm ≤ h 1 ≤ 1.04 mm; (3) 0.6mm ≤ h 2 ≤ 0.8mm.

13. The battery cell according to any one of claims 1-12, wherein, the first opening portion includes a first section and a second section connected to each other, the first section, the second section and the first body portion are sequentially distributed in the third direction, a maximum thickness of the second section is greater than a thickness of the first body portion, the maximum thickness of the second section is greater than a maximum thickness of the first section, a first step surface is formed between the second section and the first section, and the end cap overlaps on the first step surface and is connected to the first section.

14. The battery cell according to any one of claims 1-13, wherein, the second wall includes a second opening portion and a second body portion sequentially connected in the third direction, the second body portion is farther from the opening than the second opening portion, the second opening portion is connected to the end cap, and a maximum thickness of the second opening portion is greater than a thickness of the second body portion.

15. The battery cell according to any one of claims 1-14, wherein, the housing body is a prismatic structure having the openings at both ends, the number of the end caps is two, and the two end caps respectively close the two openings.

16. The battery cell according to any one of claims 1-15, wherein, the battery cell further includes an electrode assembly, the electrode assembly includes a positive electrode tab, the positive electrode tab includes a positive electrode active material, the positive electrode active material includes a nickel-containing element compound, the nickel-containing element compound includes a layered lithium-containing transition metal oxide, and a molar ratio of nickel element in the layered lithium-containing transition metal oxide to a total molar amount of transition metal elements in the layered lithium-containing transition metal oxide is not less than 50%.

17. The battery cell according to claim 16, wherein, The layered lithium-containing transition metal oxide includes Li a Ni b Co c M d O e A f , where 0 < a ≤ 1.2, 0.6 ≤ b < 1, 0 < c < 1; 0 < d < 1; 1 ≤ e ≤ 2; 0 ≤ f ≤ 1; M includes, but is not limited to, one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B; A includes, but is not limited to, one or more of N, F, S, and Cl.

18. The battery cell according to claim 17, wherein, 0.7≤b≤0.98。 19. The battery cell according to claim 17 or 18, wherein, 0.4 ≤ b / h ≤ 8.

1.

20. The battery cell according to claim 19, wherein, 1 ≤ b / h ≤ 6.

21. The battery cell according to any one of claims 1-20, wherein, the battery cell further includes an electrode assembly, the electrode assembly includes a main body portion, the main body portion is provided with an active material, the main body portion has a first surface facing the end cover, along the direction from the first body portion to the first opening portion, the first opening portion extends beyond the first surface.

22. The battery cell according to any one of claims 1-21, wherein, the housing and the end cover are welded to form a welding region, the average grain size of the portion of the first opening portion other than the welding region is greater than the average grain size of the first body portion, and the average grain size is the average grain size of the grains in the thickness direction.

23. The battery cell according to claim 22, wherein, in a cross-section of the first wall parallel to the thickness direction of the first wall, for the portion of the first opening portion located below the welding region, in the width direction of the cross-section, the number of grains is greater than or equal to 15.

24. The battery cell according to claim 22 or 23, wherein, the average grain size range of the portion of the first opening portion other than the welding region is 70 microns - 1200 microns; and / or, the average grain size range of the first body portion is 30 microns - 1000 microns.

25. A battery, comprising the battery cell according to any one of claims 1-24.

26. The battery according to claim 25, wherein, the number of the battery cells is multiple, the multiple battery cells are stacked along the second direction, and the battery further includes an end plate, and along the second direction, the end plate is disposed at the end of the multiple battery cells.

27. The battery according to claim 26, wherein, the end plate faces the second wall.

28. An electrical device, comprising the battery cell according to any one of claims 1-24 or the battery according to any one of claims 25-27, and the battery cell or the battery is used to provide electrical energy.

29. An energy storage device, comprising the battery cell according to any one of claims 1-24 or the battery according to any one of claims 25-27.

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