Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. Wherein the battery monomer comprises a shell and an electrode assembly. A containing cavity is formed in the shell. The electrode assembly is contained in the containing cavity and comprises a first pole piece, the first pole piece comprises a first main body part and a first pole lug, a first main body area and a first thinned area which are arranged in the first direction are formed on the first main body part, and the thickness of the first thinned area is smaller than that of the first main body area; the first tab is connected to one end, far away from the first main body region in the first direction, of the first thinned region; a thickening part is arranged on the cavity wall face of the containing cavity in a protruding mode, at least part of the projection of the first thinned area is located in the thickening part in the thickness direction of the first thinned area, and the thickness direction of the first thinned area is perpendicular to the first direction. By means of the thickening part, the constraint of the shell on the first thinned area of the first pole piece can be increased, so that the phenomenon that the gap of the first thinned area of the first pole piece is too large or the first thinned area of the first pole piece is bent after expansion is relieved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also growing. Among them, batteries, as core components of new energy vehicles, have high requirements in terms of reliability and service life. The battery cell of the battery usually includes a shell and an electrode assembly contained in the shell, and the shell is provided with electrode terminals. The electrode terminals are electrically connected to the electrode assembly to realize the input or output of electrical energy of the battery cell. However, the electrode assemblies of existing battery cells are prone to lithium deposition or increased internal resistance during the cycle use process, which leads to a higher risk of battery cell use and a shorter cycle life, which is not conducive to improving the service life and reliability of the battery cell. Utility Model Content

[0003] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the service life and reliability of the battery cell.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and an electrode assembly; a accommodating cavity is formed inside the shell; the electrode assembly is accommodated in the accommodating cavity, the electrode assembly comprising a first pole piece, the first pole piece comprising a first main body and a first pole ear, the first main body forming a first main area and a first thinned area arranged along a first direction, the thickness of the first thinned area is less than the thickness of the first main area, the first pole ear is connected to one end of the first thinned area away from the first main area in the first direction; wherein a thickened portion is convexly provided on the wall surface of the accommodating cavity, along the thickness direction of the first thinned area, at least part of the projection of the first thinned area is located in the thickened portion, and the thickness direction of the first thinned area is perpendicular to the first direction.

[0005] In the above technical solution, the first pole ear of the first pole piece of the electrode assembly is connected to the end of the first thinned area of ​​the first main body away from the first main body, so that the end of the first main body of the first pole piece provided with the first pole ear is formed with a thinning structure, thereby alleviating the phenomenon of stress concentration at the end of the first main body connected to the first pole ear, wherein, by convexly providing a thickened portion on the cavity wall surface of the accommodating cavity, and at least part of the projection of the part of the first pole piece of the electrode assembly forming the first thinned area in the thickness direction of the first thinned area is set to be located in the thickened portion, so as to increase the constraint and restraint of the first thinned area of ​​the first pole piece of the electrode assembly by the outer shell, thereby reducing the expandable space of the first thinned area of ​​the first pole piece during the cycle use process, so as to alleviate the phenomenon that the gap of the first thinned area of ​​the first pole piece after expansion is too large or the first pole piece is bent, and further alleviate the phenomenon that the electrolyte infiltration effect becomes worse during the later use of the electrode assembly, so as to reduce the risk of lithium plating of the electrode assembly, and alleviate the phenomenon that the internal resistance of the electrode assembly becomes larger during the later use, which is beneficial to improve the service life and reliability of the battery cell.

[0006] In some embodiments, along the first direction, at least one end of the thickened portion exceeds the first thinned area.

[0007] In the above technical solution, by setting at least one end of the thickened portion in the first direction to extend beyond the first thinned area of ​​the first pole piece, the abutment effect of the thickened portion on the first thinned area can be improved, thereby improving the effect of the outer shell on restraining and binding the first thinned area of ​​the first pole piece, thereby reducing the expandable space of the first thinned area of ​​the first pole piece during the cyclic use process, and further alleviating the phenomenon that the gap of the first thinned area of ​​the first pole piece after expansion is too large or the first pole piece is bent.

[0008] In some embodiments, along the first direction, both ends of the thickened portion extend beyond the first thinned area.

[0009] In the above technical solution, by setting the two ends of the thickened portion in the first direction to a structure that both extend beyond the first thinned area of ​​the first pole piece, the abutment effect of the thickened portion on the first thinned area can be further enhanced, thereby further improving the effect of the outer shell on restraining and binding the first thinned area of ​​the first pole piece, thereby further reducing the expandable space of the first thinned area of ​​the first pole piece during the cyclic use process, and further alleviating the phenomenon that the gap of the first thinned area of ​​the first pole piece after expansion is too large or the first pole piece is bent.

[0010] In some embodiments, along the first direction, a length of the thickened portion is less than or equal to twice a length of the first thinned area.

[0011] In the above technical solution, by setting the length of the thickened portion in the first direction to be less than or equal to twice the length of the first thinned area, the space occupied by the thickened portion in the first direction can be saved while constraining and restraining the first thinned area, which is beneficial to reducing the difficulty of protruding the thickened portion on the wall surface of the accommodating cavity and can reduce the interference between the thickened portion and the first main area of ​​the first pole piece.

[0012] In some embodiments, the thickness of the thickened portion protruding from the wall surface of the accommodating cavity is D, satisfying 0mm<D≤5mm.

[0013] In the above technical solution, by setting the thickness of the thickened portion protruding from the cavity wall of the accommodating cavity to be less than or equal to 5 mm, the phenomenon of the thickened portion occupying too much internal space of the shell can be alleviated, thereby improving the internal space utilization of the battery cell and improving the energy density of the battery cell.

[0014] In some embodiments, the electrode assembly also includes a second pole piece; the second pole piece has an opposite polarity to that of the first pole piece, the second pole piece includes a second main body portion and a second pole ear, the second main body portion is formed with a second main body area and a second thinned area arranged along the first direction, the thickness of the second thinned area is less than the thickness of the second main body area, along the first direction, the second pole ear is connected to an end of the second thinned area away from the second main body area, and the second pole ear and the first pole ear are located at the same end of the electrode assembly; wherein, along the thickness direction of the second thinned area, at least a portion of the projection of the second thinned area is located within the thickened portion, and the thickness direction of the second thinned area is perpendicular to the first direction.

[0015] In the above technical solution, the second pole ear of the second pole piece of the electrode assembly is connected to the end of the second thinned area of ​​the second main body away from the second main body, so that the end of the second main body of the second pole piece provided with the second pole ear is also formed with a thinning structure, thereby alleviating the stress concentration phenomenon at the end of the second main body connected to the second pole ear, wherein, by arranging the second pole ear of the second pole piece and the first pole ear of the first pole piece at the same end of the electrode assembly in the first direction, and at least partially arranging the projection of the part of the second pole piece of the electrode assembly forming the second thinned area in the thickness direction of the second thinned area to be located in the thickened portion, so that the outer shell The thickened portion can also increase the constraints and restraints on the second thinned area of ​​the second pole piece of the electrode assembly to reduce the expandable space of the second thinned area of ​​the second pole piece during cyclic use, thereby effectively alleviating the phenomenon that the gap in the second thinned area of ​​the second pole piece after expansion is too large or the second pole piece is bent, and can further alleviate the phenomenon that the electrolyte infiltration effect deteriorates during the later use of the electrode assembly, so as to further reduce the risk of lithium plating of the electrode assembly, and can further alleviate the phenomenon that the internal resistance of the electrode assembly increases during the later use, which is beneficial to further improve the service life and reliability of the battery cell.

[0016] In some embodiments, along the first direction, at least one end of the thickened portion exceeds the second thinned area.

[0017] In the above technical solution, by setting at least one end of the thickened portion in the first direction to extend beyond the second thinned area of ​​the second pole piece, the abutment effect of the thickened portion on the second thinned area can be improved, thereby improving the effect of the outer shell on restraining and binding the second thinned area of ​​the second pole piece, thereby reducing the expandable space of the second thinned area of ​​the second pole piece during the cycle use process, and further alleviating the phenomenon that the gap of the second thinned area of ​​the second pole piece after expansion is too large or the second pole piece is bent.

[0018] In some embodiments, along the first direction, both ends of the thickened portion extend beyond the second thinned area.

[0019] In the above technical solution, the two ends of the thickened portion in the first direction are arranged to extend beyond the second thinned area of ​​the second pole piece, so as to further enhance the abutment effect of the thickened portion on the second thinned area, thereby further enhancing the effect of the outer shell on restraining and binding the second thinned area of ​​the second pole piece, thereby further reducing the expandable space of the second thinned area of ​​the second pole piece during the recycling process, thereby further alleviating the phenomenon that the gap of the second thinned area of ​​the second pole piece after expansion is too large or the second pole piece is bent.

[0020] In some embodiments, along the first direction, a length of the thickened portion is less than or equal to twice a length of the second thinned region.

[0021] In the above technical solution, by setting the length of the thickened portion in the first direction to be less than or equal to twice the length of the second thinned area, the space occupied by the thickened portion in the first direction can be saved while constraining and restraining the second thinned area, which is beneficial to reducing the difficulty of protruding the thickened portion on the wall surface of the accommodating cavity and can reduce the interference between the thickened portion and the second main area of ​​the second pole piece.

[0022] In some embodiments, along a thickness direction of the first thinned region, projections of the first thinned region and the second thinned region at least partially overlap.

[0023] In the above technical solution, by setting the first thinned area and the second thinned area to at least partially overlap the projections of the first thinned area in the thickness direction, the first thinned area and the second thinned area can share part of the space in the first direction. On the one hand, the space occupied by the first thinned area and the second thinned area in the first direction can be saved, which is beneficial to improving the energy density of the electrode assembly. On the other hand, while the first thinned area and the second thinned area are both set corresponding to the thickened portion, the size of the thickened portion in the first direction can also be saved, so that the shell can simultaneously restrain and bind the first thinned area and the second thinned area through the thickened portion.

[0024] In some embodiments, the electrode assembly forms a straight area, and the electrode assembly also includes a second pole piece with opposite polarity to that of the first pole piece; wherein a portion of the first pole piece within the straight area and a portion of the second pole piece within the straight area are stacked along a second direction, and along the second direction, the outer shell has a first wall arranged opposite to the electrode assembly, and the thickened portion is arranged on the surface of the first wall facing the electrode assembly, and the second direction is perpendicular to the first direction.

[0025] In the above technical scheme, the electrode assembly forms a straight area, and the first pole piece and the second pole piece located in the straight area are a structure stacked along the second direction, so that the electrode assembly is a structure that expands more in the second direction, so that a thickened portion is convexly provided on the second wall of the outer shell and the electrode assembly that are arranged opposite to each other in the second direction, so that the outer shell can increase the constraint and restraint of the first thinned area of ​​the first pole piece in the second direction through the thickened portion. The battery cell adopting this structure can realize the constraint and restraint of the area where the weak structure is formed on the first pole piece of the electrode assembly in the second direction, so as to reduce the expandable space of the area where the weak structure is formed on the first pole piece of the electrode assembly in the direction of greater expansion, thereby alleviating the phenomenon that the gap of the electrode assembly is too large or the first pole piece is bent after expansion, and further reducing the phenomenon that the electrolyte infiltration effect of the electrode assembly deteriorates during the later use, so as to reduce the risk of lithium plating of the electrode assembly, and alleviate the phenomenon that the internal resistance of the electrode assembly increases during the later use.

[0026] In some embodiments, along the second direction, the projection of the first thinned area is entirely located within the thickened portion.

[0027] In the above technical solution, the projection of the first thinned area of ​​the first pole piece in the second direction is set as a whole to be located within the thickened portion, so that the thickened portion is a structure covering the first thinned area of ​​the first pole piece in the second direction, thereby enabling the thickened portion to constrain and restrain the overall weak structure of the first pole piece in the direction in which the electrode assembly expands more, so as to alleviate the phenomenon that the first thinned area of ​​the first pole piece is bent or deformed or the gap becomes larger due to excessive expansion space, which is beneficial to further alleviate the phenomenon of poor electrolyte infiltration during use of the electrode assembly.

[0028] In some embodiments, the second pole piece includes a second main body portion and a second pole ear, the second main body portion is formed with a second main area and a second thinned area arranged along the first direction, the thickness of the second thinned area is less than the thickness of the second main area, along the first direction, the second pole ear is connected to the end of the second thinned area away from the second main area, and the second pole ear and the first pole ear are located at the same end of the electrode assembly; wherein, along the second direction, the projection of the second thinned area is located as a whole within the thickened portion.

[0029] In the above technical solution, the projection of the second thinned area of ​​the second pole piece in the second direction is set as a whole to be located within the thickened portion, so that the thickened portion is a structure that covers the second thinned area of ​​the second pole piece in the second direction, thereby enabling the thickened portion to constrain and restrain the overall weak structure of the second pole piece in the direction in which the electrode assembly expands more, so as to alleviate the phenomenon that the second thinned area of ​​the second pole piece is bent or deformed or the gap becomes larger due to excessive expansion space, which is beneficial to further alleviate the phenomenon of poor electrolyte infiltration during use of the electrode assembly.

[0030] In some embodiments, along the second direction, the shell has two first walls arranged opposite to each other, the two first walls are respectively located on both sides of the electrode assembly, and the thickened portion is provided on surfaces of the two first walls facing the electrode assembly.

[0031] In the above technical solution, the outer shell has two first walls arranged opposite to each other in the second direction, the two first walls are respectively located on both sides of the electrode assembly, and thickened portions are convexly provided on the surfaces of the two first walls facing the electrode assembly. The battery cell adopting this structure can achieve abutment against the areas where the first pole pieces of the electrode assembly form weak structures on both sides in the direction where the electrode assembly expands more, which is beneficial to improving the effect of restraining and binding the areas where the first pole pieces of the electrode assembly form weak structures through the thickened portions.

[0032] In some embodiments, the electrode assembly is a winding structure, the first pole piece and the second pole piece are stacked on each other and wound around an axis extending along the first direction, so that the electrode assembly forms the straight area and two bending areas connected to the two ends of the straight area in the third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

[0033] In the above technical solution, the electrode assembly is set to a winding structure formed by winding the first pole piece and the second pole piece around an axis extending in the first direction, so that a straight area in which the first pole piece and the second pole piece are stacked on each other along the second direction is formed between two bending areas of the electrode assembly. The structure is simple and easy to manufacture.

[0034] In some embodiments, the thickened portion is an annular structure, and the thickened portion surrounds the outer side of the electrode assembly around an axis extending along the first direction.

[0035] In the above technical solution, by setting the thickened portion as an annular structure surrounding the outside of the electrode assembly, the thickened portion can constrain and restrain the first thinned area of ​​the first pole piece in the straight area of ​​the electrode assembly, and can also constrain and restrain the first thinned area of ​​the first pole piece in the bending area of ​​the electrode assembly, which is beneficial to further alleviate the phenomenon of bending deformation or enlarged gap in the first thinned area of ​​the first pole piece during use, so as to reduce the risk of poor electrolyte infiltration during use of the electrode assembly.

[0036] In some embodiments, the outer shell includes a shell and an end cover; the shell includes a bottom wall and a side wall, the side wall is arranged around the bottom wall, along the first direction, one end of the side wall is connected to the bottom wall, and the other end is enclosed to form an opening, the side wall and the bottom wall jointly define the accommodating cavity; the end cover closes the opening; wherein the thickened portion is arranged on the surface of the side wall facing the electrode assembly.

[0037] In the above technical solution, by setting the opening of the shell to be located at one end of the shell in the first direction, the end cover and the bottom wall of the shell are structures arranged along the first direction, and the thickened portion is arranged on the surface of the side wall facing the electrode assembly. Therefore, on the one hand, it is convenient to assemble the electrode assembly into the shell along the first direction, so that the thickened portion protruding from the side wall corresponds to the thinned area of ​​the first pole piece, which is beneficial to reduce the difficulty of assembling the battery cell. On the other hand, it can reduce the difficulty of protruding the thickened portion on the wall surface of the accommodating cavity of the shell.

[0038] In some embodiments, the side wall includes two first walls and two second walls, the two first walls are arranged opposite to each other along the second direction, the two second walls are arranged opposite to each other along the third direction, one first wall, one second wall, another first wall and another second wall are connected end to end in sequence, and the first direction, the second direction and the third direction are perpendicular to each other; wherein the area of ​​the surface of the first wall facing away from the electrode assembly is the largest surface among the outer surfaces of the battery cell, and the thickened portion is provided on the surface of the first wall facing the electrode assembly.

[0039] In the above technical scheme, the side wall of the shell includes two first walls arranged opposite to each other along the second direction and two second walls arranged opposite to each other along the third direction, so that the side wall has a rectangular structure. By arranging the thickened portion on the surface of the first wall facing the electrode assembly, and the outer surface of the first wall facing away from the electrode assembly is the surface with the largest area among the outer surfaces of the battery cell, the thickened portion is located on one side of the electrode assembly in the thickness direction of the battery cell. The battery cell adopting this structure can restrain and bind the area with a weak structure formed on the first pole piece of the electrode assembly in the direction of greater expansion, thereby alleviating the phenomenon of excessive gap or bending of the first pole piece of the electrode assembly after expansion, and further reducing the phenomenon of poor electrolyte wetting effect of the electrode assembly during later use, so as to reduce the risk of lithium plating of the electrode assembly and alleviate the phenomenon of increased internal resistance of the electrode assembly during later use.

[0040] In some embodiments, the first electrode sheet is a negative electrode sheet of the electrode assembly.

[0041] In the above technical solution, by setting the first pole piece as the negative pole piece of the electrode assembly, the outermost part of the electrode assembly is the first pole piece, so that the first thinned area of ​​the first pole piece of the electrode assembly which is most susceptible to deformation can be constrained and restrained by the thickened portion, so as to alleviate the phenomenon that the electrolyte infiltration effect of the electrode assembly deteriorates during the later use, thereby reducing the risk of lithium plating of the electrode assembly and alleviating the phenomenon that the internal resistance of the electrode assembly increases during the later use.

[0042] In some embodiments, the thickened portion is integrally formed with the shell.

[0043] In the above technical solution, by setting the thickened part and the outer shell as an integrally formed structure, it is beneficial to improve the connection strength between the thickened part and the outer shell, thereby improving the stability and reliability of the thickened part protruding on the wall surface of the accommodating cavity, so as to reduce the risk of the thickened part falling off during use, which is beneficial to improving the reliability and stability of the battery cell.

[0044] In some embodiments, the thickened portion is separately provided and connected to the outer shell.

[0045] In the above technical solution, by arranging the thickened portion and the outer shell as separate structures, and the thickened portion is connected to the cavity wall surface of the accommodating cavity, the battery cell adopting this structure is convenient for arranging the thickened portion on the cavity wall surface of the accommodating cavity, which is beneficial to reduce the difficulty of convexly arranging the thickened portion on the cavity wall surface of the accommodating cavity, and is convenient for replacing thickened portions of different thicknesses.

[0046] In some embodiments, a cavity is formed inside the thickened portion.

[0047] In the above technical solution, by providing a cavity inside the thickened portion, the weight of the thickened portion can be reduced, thereby reducing the overall weight of the battery cell, which is beneficial to improving the energy density of the battery cell.

[0048] In a second aspect, an embodiment of the present application further provides a battery, comprising the above-mentioned battery cell.

[0049] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery cell, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. 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 related drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0052] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0053] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0054] Figure 4 An exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0055] Figure 5 A cross-sectional view of a battery cell provided for some embodiments of the present application;

[0056] Figure 6 for Figure 5 A partial enlarged view of the battery cell at A shown;

[0057] Figure 7A cross-sectional view of an electrode assembly provided in some embodiments of the present application, perpendicular to a first direction;

[0058] Figure 8 A schematic diagram of assembling an electrode assembly and a housing of a battery cell provided in some embodiments of the present application;

[0059] Fig. 9 Cross-sectional views of battery cells provided in accordance with some other embodiments of the present application.

[0060] Icon: 1000-vehicle; 100-battery; 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-accommodating cavity; 2111-opening; 212-thickening portion; 213-housing; 2131-bottom wall; 2132-side wall; 2132a-first wall; 2132b-second wall; 214-end cover; 2141-terminal hole; 22-electrode assembly; 221-first pole piece; 2211-first main body; 2211a-first main body area; 221 1b-first thinning area; 2212-first pole ear; 222-second pole piece; 2221-second main body; 2221a-second main body area; 2221b-second thinning area; 2222-second pole ear; 223-isolating member; 224-straight area; 225-bending area; 23-electrode terminal; 24-first insulating member; 25-second insulating member; 26-sealing member; 27-current collecting member; 28-pressure relief mechanism; 200-controller; 300-motor; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0062] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; 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" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. 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 and secondary relationship.

[0063] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0064] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0066] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0067] The term "plurality" used in the present application refers to two or more (including two).

[0068] 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.

[0069] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present application.

[0070] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through.

[0071] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet 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.

[0072] 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 disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0073] 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 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.).

[0074] 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 traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 (Also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Also referred to as NCM 523 )、LiNi 0.5 Co 0.25Mn 0.25 O 2 (Also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (Also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (Also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and at least one of its modified compounds.

[0075] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0076] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0077] As an example, the negative electrode current collector may be a metal foil, a foamed metal or a composite current collector. For example, as the metal foil, aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium with a silver surface treatment may be used. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper 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.).

[0078] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0079] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0080] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells 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.

[0081] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0082] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0083] In some embodiments, the separator is a separator membrane. There may be many types of separator membranes, and any known porous separator membrane with good chemical stability and mechanical stability may be selected.

[0084] As an example, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or may be attached to the surface of the positive and negative electrodes.

[0085] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0086] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0087] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0088] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0089] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0090] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0091] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0092] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0093] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0094] 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.

[0095] In some embodiments, the electrode assembly is a laminate structure.

[0096] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0097] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0098] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0099] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0100] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0101] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0102] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0103] In some embodiments, the 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 (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0104] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes but is not limited to a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc.

[0105] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0106] 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.

[0107] 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 accommodated in the case.

[0108] 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.

[0109] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0110] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient. They are an important part of the development of new energy today. The development of battery technology must consider many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety of the battery also needs to be considered.

[0111] For a general battery cell, the battery cell usually includes a shell and an electrode assembly, the electrode assembly is arranged in the shell, and an electrode terminal is arranged on the shell, and the electrode terminal is electrically connected to the electrode assembly to realize the input or output of the electric energy of the battery cell. Among them, the electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet, and the separator is arranged between the positive electrode sheet and the negative electrode sheet to separate the positive electrode sheet and the negative electrode sheet. The electrode assembly can be a winding structure formed by winding the positive electrode sheet, the separator and the negative electrode sheet, or a stacked structure formed by stacking the positive electrode sheet, the separator and the negative electrode sheet. The area corresponding to the positive electrode sheet and the negative electrode sheet coated with the active material layer forms the main body of the electrode assembly, which is the main part of the electrode assembly where the electrochemical reaction occurs in the shell, and the area of ​​the positive electrode sheet and the negative electrode sheet not coated with the active material layer forms the positive electrode ear and the negative electrode ear respectively, and the positive electrode ear and the negative electrode ear are respectively used to be electrically connected to the two electrode terminals to output or input the positive electrode and negative electrode of the battery cell. In the related art, in order to alleviate the stress concentration phenomenon at the edge of the positive electrode sheet and the negative electrode sheet at one end of the electrode ear, the active material layer at the end of the positive electrode sheet forming the positive electrode ear is usually thinned to form a thinned area at the end of the positive electrode sheet connected to the positive electrode ear, and the active material layer at the end of the negative electrode sheet forming the negative electrode ear is thinned to form a thinned area at the end of the positive electrode sheet connected to the positive electrode ear, thereby alleviating the stress concentration phenomenon at the active material layer at the end of the electrode sheet forming the electrode ear, so that after the positive electrode sheet and the negative electrode sheet are wound or stacked to form an electrode assembly, a weak area with a large gap will be formed at the end of the main body connected to the electrode ear. However, a battery cell of this structure will cause the weak area of ​​the main body of the electrode assembly to be less constrained and restrained by the outer shell, and the weak area has a larger expansion space, which makes it easy for the weak area of ​​the main body of the electrode assembly to bend due to excessive expansion during the recycling of the battery cell, especially the outermost pole piece of the electrode assembly, which can easily lead to a larger gap between the pole pieces in the weak area of ​​the main body of the electrode assembly, causing the electrolyte infiltration effect of the electrode assembly to deteriorate during the later use, and then the electrode assembly is prone to the risk of increased internal resistance or lithium precipitation due to poor electrolyte infiltration, which is not conducive to improving the reliability and service life of the battery cell.

[0112] Based on the above considerations, in order to solve the problem of low reliability and short service life of battery cells, an embodiment of the present application provides a battery cell, which includes a shell and an electrode assembly. A housing is formed inside the shell. The electrode assembly is accommodated in the housing, and the electrode assembly includes a first pole piece, and the first pole piece includes a first main body and a first pole ear. The first main body is formed with a first main body area and a first thinned area arranged along a first direction. The thickness of the first thinned area is less than the thickness of the first main body area, and the first pole ear is connected to the first thinned area at one end away from the first main body area in the first direction. A thickened portion is convexly provided on the wall surface of the housing cavity, and along the thickness direction of the first thinned area, at least part of the projection of the first thinned area is located in the thickened portion, and the thickness direction of the first thinned area is perpendicular to the first direction.

[0113] In a battery cell of this structure, the first pole ear of the first pole piece of the electrode assembly is connected to an end of the first thinned area of ​​the first main body away from the first main body, so that the end of the first main body of the first pole piece provided with the first pole ear is formed with a thinning structure, thereby alleviating the phenomenon of stress concentration at the end of the first main body connected to the first pole ear, wherein a thickened portion is convexly provided on the cavity wall surface of the accommodating cavity, and at least a portion of the projection of the portion of the first pole piece of the electrode assembly forming the first thinned area in the thickness direction of the first thinned area is set to be located within the thickened portion, so as to increase the constraint and restraint of the first thinned area of ​​the first pole piece of the electrode assembly by the outer shell, thereby reducing the expandable space of the first thinned area of ​​the first pole piece during the cycle use process, so as to alleviate the phenomenon that the gap of the first thinned area of ​​the first pole piece after expansion is too large or the first pole piece is bent, and further alleviate the phenomenon that the electrolyte infiltration effect becomes poor during the later use of the electrode assembly, so as to reduce the risk of lithium plating of the electrode assembly, and alleviate the phenomenon that the internal resistance of the electrode assembly becomes larger during the later use, which is beneficial to improve the service life and reliability of the battery cell.

[0114] The battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical device, which is helpful to alleviate the problem of increased internal resistance or lithium deposition in the electrode assembly during use, and improve the reliability and service life of the battery cells.

[0115] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, 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., and 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 as an example of an electrical device in an embodiment of the present application.

[0117] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source or a power source for the vehicle 1000, etc. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0118] In some embodiments of the present application, the battery 100 can not only serve as an operating power source or a use power source for the vehicle 1000, but also serve 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.

[0119] Please refer to Figure 2 and Figure 3 , Figure 2 The structure explosion diagram of the battery 100 provided in some embodiments of the present application is shown in FIG. Figure 3 The schematic diagram of the structure of the battery cell 20 provided in some embodiments of the present application. The battery 100 comprises a box body 10 and a battery cell 20 , and the battery cell 20 is used to be accommodated in the box body 10 .

[0120] The box body 10 is used to provide an assembly space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cell 20. The second box body 12 may be a hollow structure with one end open, and the first box body 11 may be a plate-like structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 may also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0121] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube. Figure 2 In the embodiment, the box body 10 is in the shape of a rectangular parallelepiped.

[0122] In the battery 100, the battery cell 20 disposed in the box 10 may be one or more. When there are more than one battery cell 20 disposed in the box 10, the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 20 may be accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in mixed connection, and then the multiple battery modules may be connected in series, in parallel, or in mixed connection to form a whole, and then the whole may be accommodated in the box 10.

[0123] In some embodiments, the battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, and the busbar component is used to connect the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0124] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be in a rectangular parallelepiped, a cylinder, a prism or other shapes. For example, Figure 3 In the figure, the battery cell 20 is a rectangular parallelepiped structure.

[0125] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 4 This is an exploded view of the structure of the battery cell 20 provided in some embodiments of the present application. Figure 5 A cross-sectional view of a battery cell 20 provided in some embodiments of the present application, Figure 6 for Figure 5 The partial enlarged view of the battery cell 20 at A shown in FIG. Figure 7 A cross-sectional view of an electrode assembly 22 provided in some embodiments of the present application perpendicular to a first direction X, Figure 8Schematic diagram of assembly of the electrode assembly 22 and the shell 213 of the battery cell 20 provided in some embodiments of the present application. The present application provides a battery cell 20, and the battery cell 20 includes a shell 21 and an electrode assembly 22. A housing cavity 211 is formed inside the shell 21. The electrode assembly 22 is accommodated in the housing cavity 211, and the electrode assembly 22 includes a first pole piece 221, and the first pole piece 221 includes a first main body 2211 and a first pole ear 2212. The first main body 2211 is formed with a first main body area 2211a and a first thinned area 2211b arranged along the first direction X, and the thickness of the first thinned area 2211b is less than the thickness of the first main body area 2211a, and the first pole ear 2212 is connected to the end of the first thinned area 2211b away from the first main body area 2211a in the first direction X. A thickened portion 212 is convexly provided on the wall surface of the accommodating cavity 211. Along the thickness direction of the first thinned area 2211b, at least part of the projection of the first thinned area 2211b is located in the thickened portion 212. The thickness direction of the first thinned area 2211b is perpendicular to the first direction X.

[0126] The housing 21 can also be used to contain electrolyte, such as electrolyte. The housing 21 can be in various structural forms, such as a cylinder or a cuboid. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0127] In some embodiments, the housing 21 may include a shell 213 and an end cap 214, wherein a housing cavity 211 is formed inside the shell 213, and the housing cavity 211 is used to accommodate the electrode assembly 22, and the housing cavity 211 has an opening 2111, that is, the shell 213 is a hollow structure with an opening 2111 at one end, and the end cap 214 covers the opening 2111 of the shell 213 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte. Exemplarily, the opening 2111 is provided at one end of the shell 213 in the first direction X.

[0128] In which, the shell 213 includes an integrally formed bottom wall 2131 and a side wall 2132, the side wall 2132 is arranged around the bottom wall 2131, one end of the side wall 2132 in the first direction X is connected to the bottom wall 2131, and the other end is enclosed to form an opening 2111 for the end cover 214 to cover, and the side wall 2132 and the bottom wall 2131 are enclosed to form a accommodating cavity 211 for accommodating the electrode assembly 22.

[0129] For example, in Figure 3 , Figure 4 and Figure 5In the figure, the shell 213 is in the shape of a rectangular parallelepiped, and the side wall 2132 of the shell 213 includes two first walls 2132a and two second walls 2132b. The two first walls 2132a are arranged opposite to each other along the second direction Y, and the two second walls 2132b are arranged opposite to each other along the third direction Z. One first wall 2132a, one second wall 2132b, another first wall 2132a and another second wall 2132b are connected end to end in sequence, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0130] Among them, the thickened portion 212 is convexly arranged on the cavity wall surface of the accommodating cavity 211, and the thickened portion 212 is arranged corresponding to the first thinned area 2211b of the first electrode piece 221. The thickened portion 212 can be convexly arranged on the first wall 2132a, or convexly arranged on the second wall 2132b, or the first wall 2132a and the second wall 2132b are both convexly provided with the thickened portion 212, that is, the thickened portion 212 is an annular structure surrounding the outer side of the electrode assembly 22. Of course, in other embodiments, if the arrangement direction of the first main body area 2211a and the first thinned area 2211b of the first main body 2211 is a structure perpendicular to the first direction X, that is, the electrode assembly 22 is a structure lying flat in the shell 213, then the thickened portion 212 can also be convexly arranged on the end cover 214 or the bottom wall 2131. It should be noted that if the shell 213 is cylindrical, that is, the side wall 2132 of the shell 213 is a cylindrical structure extending along the first direction X, the thickened portion 212 can be an annular structure surrounding the outer side of the electrode assembly 22, or it can be an arc-shaped structure extending circumferentially along the side wall 2132.

[0131] When assembling the battery cell 20 , the electrode assembly 22 may be placed into the housing 213 first, and the housing 213 may be filled with electrolyte. Then, the end cap 214 may be closed on the opening 2111 of the housing 213 to complete the assembly of the battery cell 20 .

[0132] The shell 213 can be in various shapes, such as a cylinder, a cuboid, or a prism structure. The shape of the shell 213 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a shell 213 with a cylindrical structure can be selected; if the electrode assembly 22 is a cuboid structure, a shell 213 with a cuboid structure can be selected. Of course, the structure of the end cap 214 can also be various, such as the end cap 214 being a plate-like structure or a hollow structure with one end open. For example, in Figure 3 In the embodiment, the shell 213 is a rectangular parallelepiped structure, and the end cover 214 is a plate-shaped structure.

[0133] Of course, it is understandable that the outer shell 21 is not limited to the above structure, and the outer shell 21 may also be other structures. For example, the outer shell 21 may include a shell body 213 and two end caps 214. The shell body 213 is a hollow structure with openings 2111 on opposite sides. One end cap 214 corresponds to an opening 2111 of the shell body 213 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte. That is, the shell body 213 is formed with openings 2111 on opposite sides, and the two end caps 214 are respectively covered on the two sides of the shell body 213 to close the corresponding openings 2111.

[0134] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may further include two electrode terminals 23 , and both of the two electrode terminals 23 function to be electrically connected to the electrode assembly 22 to facilitate output or input of electrical energy from the battery cell 20 .

[0135] Exemplarily, the electrode terminal 23 may be made of various materials, for example, the electrode terminal 23 may be made of copper, iron, aluminum, steel or aluminum alloy.

[0136] It should be noted that the two electrode terminals 23 are both insulated and mounted on the end cap 214, that is, the two electrode terminals 23 are not electrically connected to the end cap 214 of the housing 21. Of course, in other embodiments, the two electrode terminals 23 may also be both disposed on the housing 213 of the housing 21, or one of the two electrode terminals 23 may be disposed on the end cap 214, and the other electrode terminal 23 may be disposed on the housing 213.

[0137] See also Figure 5 and Figure 6 As shown, a terminal hole 2141 is provided on the end cover 214, and the terminal hole 2141 passes through both sides of the end cover 214 along the first direction X. The electrode terminal 23 is inserted into the terminal hole 2141 along the first direction X to facilitate electrical connection between the electrode terminal 23 and the electrode tab of the electrode assembly 22.

[0138] Among them, the battery cell 20 can also include two first insulating members 24 and a second insulating member 25. The first insulating member 24 is arranged in a one-to-one correspondence with the electrode terminal 23. At least a portion of the first insulating member 24 is arranged between the electrode terminal 23 and the hole wall of the terminal hole 2141. The second insulating member 25 is arranged on the side of the end cover 214 facing the electrode assembly 22, and at least a portion of the second insulating member 25 is located between the electrode terminal 23 and the end cover 214. The first insulating member 24 and the second insulating member 25 are configured to cooperate with the insulated isolation of the electrode terminal 23 and the end cover 214 to achieve the insulated installation of the electrode terminal 23 on the end cover 214.

[0139] Exemplarily, the first insulating member 24 and the second insulating member 25 may be made of various materials, such as rubber, silicone or plastic.

[0140] exist Figure 5 and Figure 6 In the embodiment, the battery cell 20 may further include two seals 26 , which are arranged one-to-one with the electrode terminals 23 , and are arranged between the end cover 214 and the electrode terminal 23 , and are configured to seal the gap between the electrode terminal 23 and the hole wall of the terminal hole 2141 .

[0141] Exemplarily, the material of the sealing member 26 may be rubber, silicone or plastic.

[0142] It should be noted that the electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. The electrode assembly 22 may include a first pole piece 221, a second pole piece 222 and an isolating member 223. The polarities of the first pole piece 221 and the second pole piece 222 are opposite, and the isolating member 223 is disposed between the first pole piece 221 and the second pole piece 222 to insulate and isolate the first pole piece 221 and the second pole piece 222. The structure of the electrode assembly 22 may be various. For example, the electrode assembly 22 may be a wound structure formed by winding the first pole piece 221, the isolating member 223 and the second pole piece 222, or a stacked structure formed by stacking the first pole piece 221, the isolating member 223 and the second pole piece 222. By way of example, in Figure 7 In the embodiment, the electrode assembly 22 is a wound structure formed by winding a first electrode sheet 221, a separator 223, and a second electrode sheet 222, and the winding center axis of the electrode assembly 22 extends along the first direction X, so that the electrode assembly 22 is formed with a straight region 224 and two bending regions 225 connected to both ends of the straight region 224 in the third direction Z. It should be noted that the portion of the first electrode sheet 221 located in the straight region 224 and the portion of the second electrode sheet 222 located in the straight region 224 are alternately stacked along the second direction Y.

[0143] The polarities of the first electrode 221 and the second electrode 222 are opposite, that is, the first electrode 221 and the second electrode 222 are respectively the positive and negative electrodes of the electrode assembly 22. Figure 7 In the embodiment, the first pole piece 221 is the negative pole piece of the electrode assembly 22, so that the outermost circle of the wound structure of the electrode assembly 22 is the first pole piece 221, and correspondingly, the second pole piece 222 is the positive pole piece of the electrode assembly 22. Of course, in other embodiments, the first pole piece 221 is the positive pole piece of the electrode assembly 22, and correspondingly, the second pole piece 222 is the negative pole piece of the electrode assembly 22.

[0144] Exemplarily, the isolation member 223 is an isolation membrane, and the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0145] Optionally, the number of electrode assemblies 22 contained in the housing 21 may be one or more. Figure 4 In the embodiment, the housing 21 of the battery cell 20 is provided with two electrode assemblies 22, and the two electrode assemblies 22 are stacked in the thickness direction, that is, the two electrode assemblies 22 are stacked along the second direction Y, the first direction X is the height direction of the battery cell 20, the second direction Y is the thickness direction of the battery cell 20, and the third direction Z is the length direction of the battery cell 20. Of course, in other embodiments, the number of electrode assemblies 22 accommodated in the housing 21 may also be one, three, four, five, six, seven or eight, etc.

[0146] In the examples of this application, see Figure 8 As shown, the first pole piece 221 includes a first main body 2211 and a first pole ear 2212. The first main body 2211 is the main component of the first pole piece 221 for electrochemical reaction in the battery cell 20, and the first pole ear 2212 is used to be electrically connected to one of the two electrode terminals 23 to input or output the electric energy of the first pole piece 221. The first pole ear 2212 is a component formed by mutually stacking and connecting the regions on the first pole piece 221 that are not coated with the active material layer. If the first pole piece 221 is the negative pole piece of the electrode assembly 22, the first pole ear 2212 is the negative pole ear of the electrode assembly 22; if the first pole piece 221 is the positive pole piece of the electrode assembly 22, the first pole ear 2212 is the positive pole ear of the electrode assembly 22. Similarly, the second pole piece 222 includes a second main body 2221 and a second pole ear 2222. The second main body 2221 is the main component of the second pole piece 222 for electrochemical reaction in the battery cell 20, and the second pole ear 2222 is used to be electrically connected to the other electrode terminal 23 of the two electrode terminals 23 to play the role of inputting or outputting the electric energy of the second pole piece 222. The second pole ear 2222 is a component formed by stacking and connecting the regions on the second pole piece 222 that are not coated with the active material layer. If the second pole piece 222 is the positive pole piece of the electrode assembly 22, the second pole ear 2222 is the positive pole ear of the electrode assembly 22; if the second pole piece 222 is the negative pole piece of the electrode assembly 22, the second pole ear 2222 is the negative pole ear of the electrode assembly 22.

[0147] For example, in Figure 4 and Figure 8In the embodiment, the first pole tab 2212 is connected to one end of the first main body 2211 facing the end cap 214 in the first direction X, that is, in the first direction X, the first pole tab 2212 is located between the first main body 2211 and the end cap 214, so that the first pole tab 2212 is electrically connected to one of the two electrode terminals 23. Similarly, the second pole tab 2222 is connected to one end of the second main body 2221 facing the end cap 214 in the first direction X, that is, in the first direction X, the second pole tab 2222 is located between the second main body 2221 and the end cap 214, so that the second pole tab 2222 is electrically connected to the other of the two electrode terminals 23.

[0148] The first main body 2211 is formed with a first main body area 2211a and a first thinned area 2211b arranged along the first direction X. The thickness of the first thinned area 2211b is less than that of the first main body area 2211a. The first pole ear 2212 is connected to an end of the first thinned area 2211b away from the first main body area 2211a in the first direction X. That is, see Figure 8 As shown, an area where the active material layer is thinned is formed at one end of the first main body 2211 connected to the first pole ear 2212 in the first direction X, and the area is the first thinned area 2211b of the first main body 2211, and the area where the active material layer is not thinned is the first main body area 2211a of the first main body 2211, so that the thickness of the first main body area 2211a is greater than the thickness of the first thinned area 2211b, and the first main body area 2211a, the first thinned area 2211b and the first pole ear 2212 are arranged in sequence along the first direction X.

[0149] A thickened portion 212 is convexly provided on the wall surface of the accommodating cavity 211 , that is, a thickened portion 212 is provided on the inner surface of the shell 21 facing the electrode assembly 22 .

[0150] Along the thickness direction of the first thinned zone 2211b, at least part of the projection of the first thinned zone 2211b is located in the thickened portion 212, that is, in the thickness direction of the first thinned zone 2211b, the projection of the first thinned zone 2211b overlaps with at least part of the projection of the thickened portion 212, so that the thickened portion 212 covers at least part of the first thinned zone 2211b in the thickness direction of the first thinned zone 2211b, that is, when the first thinned zone 2211b of the first pole piece 221 expands, the first thinned zone 2211b can directly or indirectly abut against at least part of the thickened portion 212 in its thickness direction.

[0151] It should be noted that the thickness direction of the first skived area 2211b is also the thickness direction of the first pole piece 221. If the electrode assembly 22 is a laminated structure formed by alternately stacking the first pole piece 221 and the second pole piece 222, the thickness direction of the first skived area 2211b is the stacking direction of the first pole piece 221 and the second pole piece 222, and is also the thickness direction of the electrode assembly 22; if the electrode assembly 22 is a wound structure formed by winding the first pole piece 221 and the second pole piece 222, the thickness of the first skived area 2211b is the radial direction of the electrode assembly 22, that is, in a plane perpendicular to the first direction X, the winding center axis of the electrode assembly 22 points to the direction of the outer edge of the electrode assembly 22 or the outer edge of the electrode assembly 22 points to the direction of the winding center axis of the electrode assembly 22.

[0152] Optionally, the first pole tab 2212 of the first pole piece 221 may be directly connected to one of the two electrode terminals 23, such as by welding or abutment, or indirectly connected through other components. Similarly, the second pole tab 2222 of the second pole piece 222 may be directly connected to the other of the two electrode terminals 23, such as by welding or abutment, or indirectly connected through other components.

[0153] In some embodiments, see Figure 4 , Figure 5 and Figure 6 As shown, the battery cell 20 may also include two current collecting components 27, both of which are arranged in the outer shell 21, one current collecting component 27 connects the first pole ear 2212 of the first pole sheet 221 and an electrode terminal 23, and the other current collecting component 27 connects the second pole ear 2222 of the second pole sheet 222 and another electrode terminal 23, so as to realize the electrical connection between the electrode assembly 22 and the two electrode terminals 23.

[0154] Exemplarily, the material of the current collecting member 27 can be various, for example, copper, iron, aluminum, steel or aluminum alloy.

[0155] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may further include a pressure relief mechanism 28, which is disposed on the end cover 214 and is used to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value. Of course, in other embodiments, the pressure relief mechanism 28 may also be disposed on the housing 213.

[0156] Optionally, the pressure relief mechanism 28 and the end cover 214 may be an integrally formed structure or a separately arranged structure. Figure 4In the embodiment, the pressure relief mechanism 28 and the end cover 214 are split structures, and the pressure relief mechanism 28 can be connected to the end cover 214 by welding or other methods. Correspondingly, the pressure relief mechanism 28 can be a pressure relief component such as an explosion-proof valve, an explosion-proof disk, an air valve, a pressure relief valve or a safety valve. Of course, in other embodiments, the pressure relief mechanism 28 and the end cover 214 can also be an integrally formed structure, and the pressure relief mechanism 28 is a region on the end cover 214 where a weak structure is formed, for example, a region on the end cover 214 where a notch groove is provided.

[0157] In the present embodiment, the first pole ear 2212 of the first pole piece 221 of the electrode assembly 22 is connected to the end of the first thinned area 2211b of the first main body 2211 away from the first main body area 2211a, so that the end of the first main body 2211 of the first pole piece 221 provided with the first pole ear 2212 is formed with a thinning structure, thereby alleviating the stress concentration phenomenon at the end of the first main body 2211 connected to the first pole ear 2212, wherein, by convexly providing a thickened portion 212 on the cavity wall surface of the accommodating cavity 211, and at least a portion of the projection of the portion of the first pole piece 221 of the electrode assembly 22 that forms the first thinned area 2211b in the thickness direction of the first thinned area 2211b is set to be located The thickened portion 212 is used to increase the constraint and restraint of the outer shell 21 on the first thinned area 2211b of the first pole piece 221 of the electrode assembly 22, thereby reducing the expandable space of the first thinned area 2211b of the first pole piece 221 during the cycle use process, so as to alleviate the phenomenon that the gap between the first thinned area 2211b of the first pole piece 221 is too large after expansion or the first pole piece 221 is bent, and thus the phenomenon that the electrolyte infiltration effect of the electrode assembly 22 deteriorates during the later use can be alleviated, so as to reduce the risk of lithium plating of the electrode assembly 22, and can alleviate the phenomenon that the internal resistance of the electrode assembly 22 increases during the later use, which is beneficial to improve the service life and reliability of the battery cell 20.

[0158] According to some embodiments of the present application, see Figure 6 and Figure 8 As shown, at least one end of the thickened portion 212 exceeds the first thinned area 2211b along the first direction X. That is, the thickened portion 212 may have only one end in the first direction X exceeding the first thinned area 2211b, or both ends in the first direction X exceeding the first thinned area 2211b.

[0159] Among them, if the thickened portion 212 is a structure in which only one end in the first direction X exceeds the first thinned area 2211b, then the end of the thickened portion 212 close to the opening 2111 in the first direction X may exceed the first thinned area 2211b, or the end of the thickened portion 212 far from the opening 2111 in the first direction X may exceed the first thinned area 2211b.

[0160] In this embodiment, by setting at least one end of the thickened portion 212 in the first direction X to extend beyond the first thinned area 2211b of the first pole piece 221, the abutment effect of the thickened portion 212 on the first thinned area 2211b can be improved, thereby improving the effect of the shell 21 on restraining and binding the first thinned area 2211b of the first pole piece 221, thereby reducing the expandable space of the first thinned area 2211b of the first pole piece 221 during the cycle use process, thereby further alleviating the phenomenon that the gap of the first thinned area 2211b of the first pole piece 221 after expansion is too large or the first pole piece 221 is bent.

[0161] In some embodiments, see Figure 6 and Figure 8 As shown, along the first direction X, both ends of the thickened portion 212 exceed the first thinned area 2211 b. In other words, both ends of the first thinned area 2211 b in the first direction X are located between both ends of the thickened portion 212 in the first direction X.

[0162] In this embodiment, the two ends of the thickened portion 212 in the first direction X are arranged to extend beyond the first thinned area 2211b of the first pole piece 221, so as to further enhance the abutment effect of the thickened portion 212 on the first thinned area 2211b, thereby further enhancing the effect of the outer shell 21 on restraining and binding the first thinned area 2211b of the first pole piece 221, thereby further reducing the expandable space of the first thinned area 2211b of the first pole piece 221 during the cycle use, thereby further alleviating the phenomenon that the gap of the first thinned area 2211b of the first pole piece 221 after expansion is too large or the first pole piece 221 is bent.

[0163] According to some embodiments of the present application, see Figure 6 As shown, along the first direction X, the length of the thickened portion 212 is less than or equal to twice the length of the first thinned area 2211 b.

[0164] In this embodiment, by setting the length of the thickened portion 212 in the first direction X to be less than or equal to twice the length of the first thinned area 2211b, the first thinned area 2211b can be constrained and restrained while saving the space occupied by the thickened portion 212 in the first direction X, which is beneficial to reducing the difficulty of protruding the thickened portion 212 on the wall surface of the accommodating cavity 211 and reducing the interference between the thickened portion 212 and the first main area 2211a of the first pole piece 221.

[0165] According to some embodiments of this application, please continue to refer to Figure 6 As shown, the thickness of the thickened portion 212 protruding from the wall surface of the accommodating cavity 211 is D, which satisfies 0mm<D≤5mm.

[0166] Among them, the thickness D of the thickened portion 212 protruding from the cavity wall of the accommodating cavity 211 can be 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc.

[0167] In this embodiment, the thickness of the thickened portion 212 protruding from the wall of the accommodating cavity 211 is set to be less than or equal to 5 mm, so as to alleviate the phenomenon that the thickened portion 212 occupies too much internal space of the outer shell 21, thereby improving the internal space utilization of the battery cell 20 and improving the energy density of the battery cell 20.

[0168] According to some embodiments of the present application, see Figure 6 , Figure 7 and Figure 8 As shown, the electrode assembly 22 further includes a second pole piece 222. The second pole piece 222 has an opposite polarity to the first pole piece 221. The second pole piece 222 includes a second main body portion 2221 and a second pole ear 2222. The second main body portion 2221 is formed with a second main body region 2221a and a second thinned region 2221b arranged along the first direction X. The thickness of the second thinned region 2221b is less than the thickness of the second main body region 2221a. Along the first direction X, the second pole ear 2222 is connected to an end of the second thinned region 2221b away from the second main body region 2221a, and the second pole ear 2222 and the first pole ear 2212 are located at the same end of the electrode assembly 22. Along the thickness direction of the second thinned region 2221b, at least part of the projection of the second thinned region 2221b is located in the thickened portion 212, and the thickness direction of the second thinned region 2221b is perpendicular to the first direction X.

[0169] The polarity of the second electrode piece 222 is opposite to that of the first electrode piece 221 , that is, the second electrode piece 222 and the first electrode piece 221 are respectively the positive and negative electrode pieces of the electrode assembly 22 .

[0170] Along the first direction X, the second pole ear 2222 and the first pole ear 2212 are located at the same end of the electrode assembly 22, that is, the second pole ear 2222 is connected to one end of the second main body 2221 in the first direction X close to the first pole ear 2212, so that the second pole ear 2222 is also connected to the end of the second main body 2221 facing the end cover 214 in the first direction X, that is, in the first direction X, the second pole ear 2222 is located between the second main body 2221 and the end cover 214, so as to facilitate the electrical connection between the second pole ear 2222 and one of the two electrode terminals 23.

[0171] The second main body 2221 is formed with a second main body area 2221a and a second thinned area 2221b arranged along the first direction X. The thickness of the second thinned area 2221b is less than that of the second main body area 2221a. The second pole ear 2222 is connected to an end of the second thinned area 2221b away from the second main body area 2221a. Figure 8 As shown, an area where the active material layer is thinned is formed at one end of the second main body 2221 connected to the second pole ear 2222 in the first direction X, and the area is the second thinned area 2221b of the second main body 2221, and the area where the active material layer is not thinned is the second main body area 2221a of the second main body 2221, so that the thickness of the second main body area 2221a is greater than the thickness of the second thinned area 2221b, and the second main body area 2221a, the second thinned area 2221b and the second pole ear 2222 are arranged in sequence along the first direction X.

[0172] Along the thickness direction of the second thinned zone 2221b, at least part of the projection of the second thinned zone 2221b is located in the thickened portion 212, that is, in the thickness direction of the second thinned zone 2221b, the projection of the second thinned zone 2221b overlaps with at least part of the projection of the thickened portion 212, so that the thickened portion 212 covers at least part of the second thinned zone 2221b in the thickness direction of the second thinned zone 2221b, that is, when the second thinned zone 2221b of the second pole piece 222 expands, the second thinned zone 2221b can directly or indirectly abut against at least part of the thickened portion 212 in its thickness direction.

[0173] It should be noted that the thickness direction of the second thinned zone 2221b is also the thickness direction of the second pole piece 222. In the electrode assembly 22 of a stacked structure or the electrode assembly 22 of a wound structure, the first pole piece 221 and the second pole piece 222 are both stacked on top of each other, so that the thickness direction of the second thinned zone 2221b is consistent with the thickness direction of the first thinned zone 2211b. If the electrode assembly 22 is a laminated structure formed by alternating the first electrode piece 221 and the second electrode piece 222 in sequence, the thickness direction of the second thinned area 2221b is the stacking direction of the first electrode piece 221 and the second electrode piece 222, and is also the thickness direction of the electrode assembly 22; if the electrode assembly 22 is a wound structure formed by winding the first electrode piece 221 and the second electrode piece 222, the thickness of the second thinned area 2221b is the radial direction of the electrode assembly 22, that is, in a plane perpendicular to the first direction X, the winding center axis of the electrode assembly 22 points to the direction of the outer edge of the electrode assembly 22 or the outer edge of the electrode assembly 22 points to the direction of the winding center axis of the electrode assembly 22.

[0174] In this embodiment, the second pole ear 2222 of the second pole piece 222 of the electrode assembly 22 is connected to the end of the second thinned area 2221b of the second main body 2221 away from the second main body area 2221a, so that the end of the second main body 2221 of the second pole piece 222 provided with the second pole ear 2222 is also formed with a thinning structure, thereby alleviating the stress concentration phenomenon at the end of the second main body 2221 connected to the second pole ear 2222, wherein the second pole ear 2222 and the first pole ear 2212 of the first pole piece 221 are arranged at the same end of the electrode assembly 22 in the first direction X, and at least a part of the projection of the part of the second pole piece 222 of the electrode assembly 22 that forms the second thinned area 2221b in the thickness direction of the second thinned area 2221b is arranged It is arranged to be located in the thickened portion 212, so that the outer shell 21 can also increase the constraint and restraint on the second thinned area 2221b of the second pole piece 222 of the electrode assembly 22 through the thickened portion 212, so as to reduce the expandable space of the second thinned area 2221b of the second pole piece 222 during the cycle use, thereby effectively alleviating the phenomenon that the gap of the second thinned area 2221b of the second pole piece 222 after expansion is too large or the second pole piece 222 is bent, and further alleviates the phenomenon that the electrolyte infiltration effect of the electrode assembly 22 is deteriorated during the later use, so as to further reduce the risk of lithium plating of the electrode assembly 22, and can further alleviate the phenomenon that the internal resistance of the electrode assembly 22 becomes larger during the later use, which is beneficial to further improve the service life and reliability of the battery cell 20.

[0175] According to some embodiments of the present application, see Figure 8 As shown, at least one end of the thickened portion 212 exceeds the second thinned area 2221b along the first direction X. That is, the thickened portion 212 may have only one end in the first direction X exceeding the second thinned area 2221b, or both ends in the first direction X exceeding the second thinned area 2221b.

[0176] Among them, if the thickened portion 212 is a structure in which only one end in the first direction X exceeds the second thinned area 2221b, then the end of the thickened portion 212 close to the opening 2111 in the first direction X may exceed the second thinned area 2221b, or the end of the thickened portion 212 far from the opening 2111 in the first direction X may exceed the second thinned area 2221b.

[0177] In this embodiment, by setting at least one end of the thickened portion 212 in the first direction X to extend beyond the second thinned area 2221b of the second pole piece 222, the abutment effect of the thickened portion 212 on the second thinned area 2221b can be improved, thereby improving the effect of the shell 21 on restraining and binding the second thinned area 2221b of the second pole piece 222, thereby reducing the expandable space of the second thinned area 2221b of the second pole piece 222 during the cycle use process, thereby further alleviating the phenomenon that the gap of the second thinned area 2221b of the second pole piece 222 after expansion is too large or the second pole piece 222 is bent.

[0178] In some embodiments, please see Figure 8 As shown, both ends of the thickened portion 212 exceed the second thinned area 2221 b along the first direction X. That is, both ends of the second thinned area 2221 b in the first direction X are located between both ends of the thickened portion 212 in the first direction X.

[0179] In this embodiment, the two ends of the thickened portion 212 in the first direction X are arranged to extend beyond the second thinned area 2221b of the second pole piece 222, so as to further enhance the abutment effect of the thickened portion 212 on the second thinned area 2221b, thereby further enhancing the effect of the outer shell 21 on restraining and binding the second thinned area 2221b of the second pole piece 222, thereby further reducing the expandable space of the second thinned area 2221b of the second pole piece 222 during the cycle use, thereby further alleviating the phenomenon that the gap of the second thinned area 2221b of the second pole piece 222 after expansion is too large or the second pole piece 222 is bent.

[0180] According to some embodiments of this application, see Figure 8 As shown, along the first direction X, the length of the thickened portion 212 is less than or equal to twice the length of the second thinned area 2221 b.

[0181] In this embodiment, by setting the length of the thickened portion 212 in the first direction X to be less than or equal to twice the length of the second thinned area 2221b, the second thinned area 2221b can be constrained and bound while saving the space occupied by the thickened portion 212 in the first direction X, which is beneficial to reducing the difficulty of protruding the thickened portion 212 on the wall surface of the accommodating cavity 211 and reducing the interference between the thickened portion 212 and the second main area 2221a of the second pole piece 222.

[0182] According to some embodiments of the present application, see Figure 6 , Figure 7 and Figure 8As shown, along the thickness direction of the first thinned area 2211b, the projections of the first thinned area 2211b and the second thinned area 2221b at least partially overlap. That is, in the thickness direction of the first thinned area 2211b, at least a portion of the first thinned area 2211b is arranged opposite to the second thinned area 2221b.

[0183] For example, in Figure 8 In the embodiment, the first electrode sheet 221 is a negative electrode sheet, and the second electrode sheet 222 is a positive electrode sheet. Along the first direction X, one end of the first thinned area 2211b is connected to the first main area 2211a, and one end of the second thinned area 2221b is connected to the second main area 2221a, and one end of the first thinned area 2211b away from the first main area 2211a in the first direction X exceeds one end of the second thinned area 2221b away from the second main area 2221a in the first direction X, so that the projection of the end of the second thinned area 2221b away from the second main area 2221a in the first direction X in the thickness direction of the first thinned area 2211b is located within the first thinned area 2211b, and the projection of the end of the second thinned area 2221b connected to the second main area 2221a in the first direction X in the thickness direction of the first thinned area 2211b is located within the first thinned area 2211a, thereby reducing the risk of lithium plating of the electrode assembly 22.

[0184] In this embodiment, by setting the first thinned area 2211b and the second thinned area 2221b to at least partially overlap the projection of the first thinned area 2211b in the thickness direction of the first thinned area 2211b, the first thinned area 2211b and the second thinned area 2221b can share part of the space in the first direction X. On the one hand, the space occupied by the first thinned area 2211b and the second thinned area 2221b in the first direction X can be saved, which is beneficial to improving the energy density of the electrode assembly 22. On the other hand, while the first thinned area 2211b and the second thinned area 2221b are both set corresponding to the thickened portion 212, the size of the thickened portion 212 in the first direction X can also be saved, so that the shell 21 can simultaneously restrain and bind the first thinned area 2211b and the second thinned area 2221b through the thickened portion 212.

[0185] According to some embodiments of the present application, see Figure 4 , Figure 5 , Figure 7 and Figure 8As shown, the electrode assembly 22 is formed with a straight area 224, and the electrode assembly 22 also includes a second electrode piece 222 having a polarity opposite to that of the first electrode piece 221. The portion of the first electrode piece 221 in the straight area 224 and the portion of the second electrode piece 222 in the straight area 224 are stacked along the second direction Y. Along the second direction Y, the housing 21 has a first wall 2132a arranged opposite to the electrode assembly 22, and a thickened portion 212 is arranged on the surface of the first wall 2132a facing the electrode assembly 22. The second direction Y is perpendicular to the first direction X.

[0186] The electrode assembly 22 is formed with a straight region 224, that is, the electrode assembly 22 is formed with a straight structure region. Figure 7 In the embodiment, the electrode assembly 22 is a winding structure formed by stacking the first pole piece 221 and the second pole piece 222 and winding around an axis extending along the first direction X, then the region in which the straight structure is formed in the middle part of the electrode assembly 22 in the third direction Z is the straight region 224, and the electrode assembly 22 is also formed with a bending region 225 respectively connected to the two ends of the straight region 224 in the third direction Z, so that the portion of the first pole piece 221 in the straight region 224 and the portion of the second pole piece 222 in the straight region 224 are stacked along the second direction Y. Of course, in some embodiments, the electrode assembly 22 may also be a laminated structure formed by alternately stacking the first pole piece 221 and the second pole piece 222 in the second direction Y. In this embodiment, the entire electrode assembly 22 forms the straight region 224, that is, the electrode assembly 22 is only formed with the straight region 224.

[0187] Along the second direction Y, the housing 21 has a first wall 2132a arranged opposite to the electrode assembly 22, that is, the housing 21 includes at least one first wall 2132a in the second direction Y, and the first wall 2132a is located on one side of the electrode assembly 22 in the second direction Y.

[0188] A thickened portion 212 is provided on the surface of the first wall 2132a facing the electrode assembly 22, that is, a thickened portion 212 is provided on at least one side of the electrode assembly 22 in the second direction Y or the thickness direction of the straight area 224, so that the thickened portion 212 can constrain and restrain the electrode assembly 22 in the thickness direction of the straight area 224.

[0189] For example, in Figure 6 and Figure 8In the embodiment, the outer shell 21 has two first walls 2132a that are relatively arranged in the second direction Y, and the two first walls 2132a are respectively located on both sides of the electrode assembly 22 in the second direction Y. In this embodiment, only one of the two first walls 2132a may have a thickened portion 212 on its surface facing the electrode assembly 22, or both first walls 2132a may have a thickened portion 212 on their surfaces facing the electrode assembly 22.

[0190] In this embodiment, the electrode assembly 22 is formed with a straight area 224, and the first pole piece 221 and the second pole piece 222 located in the straight area 224 are stacked along the second direction Y, so that the electrode assembly 22 is a structure with a large expansion in the second direction Y, so that the thickened portion 212 is convexly provided on the second wall 2132b of the shell 21 and the electrode assembly 22 that are arranged opposite to each other along the second direction Y, so that the shell 21 can increase the constraint and restraint of the first thinned area 2211b of the first pole piece 221 in the second direction Y through the thickened portion 212, and the battery cell 20 using this structure can achieve The area where the weak structure is formed on the first pole piece 221 of the electrode assembly 22 is constrained and bound in the second direction Y to reduce the expandable space in the direction of greater expansion in the area where the weak structure is formed on the first pole piece 221 of the electrode assembly 22, thereby alleviating the phenomenon of excessive gap or bending of the first pole piece 221 after expansion of the electrode assembly 22, and further reducing the phenomenon of poor electrolyte infiltration effect during the later use of the electrode assembly 22, thereby reducing the risk of lithium plating of the electrode assembly 22 and alleviating the phenomenon of increased internal resistance of the electrode assembly 22 during the later use.

[0191] In some embodiments, see Figure 8 As shown, along the second direction Y, the projection of the first thinned area 2211b is entirely located within the thickened portion 212. That is, the thickened portion 212 covers the first thinned area 2211b of the first pole piece 221 in the second direction Y.

[0192] In this embodiment, the projection of the first thinned area 2211b of the first pole piece 221 in the second direction Y is set as a whole to be located within the thickened portion 212, so that the thickened portion 212 is a structure that covers the first thinned area 2211b of the first pole piece 221 in the second direction Y, thereby enabling the thickened portion 212 to constrain and restrain the overall weak structure of the first pole piece 221 in the direction in which the electrode assembly 22 expands more, so as to alleviate the phenomenon that the first thinned area 2211b of the first pole piece 221 is bent or deformed or the gap becomes larger due to excessive expansion space, which is beneficial to further alleviate the phenomenon of poor electrolyte infiltration of the electrode assembly 22 during use.

[0193] In some embodiments, please see Figure 8 As shown, the second pole piece 222 includes a second main body portion 2221 and a second pole ear 2222, the second main body portion 2221 is formed with a second main body area 2221a and a second thinned area 2221b arranged along the first direction X, the thickness of the second thinned area 2221b is less than the thickness of the second main body area 2221a, along the first direction X, the second pole ear 2222 is connected to the end of the second thinned area 2221b away from the second main body area 2221a, and the second pole ear 2222 and the first pole ear 2212 are located at the same end of the electrode assembly 22. Along the second direction Y, the projection of the second thinned area 2221b is located in the thickened portion 212 as a whole. That is, the thickened portion 212 covers the second thinned area 2221b of the second pole piece 222 in the second direction Y.

[0194] It should be noted that in the embodiment where the first pole piece 221 is formed with a first thinned area 2211b and the second pole piece 222 is formed with a second thinned area 2221b, the projections of the first thinned area 2211b of the first pole piece 221 and the second thinned area 2221b of the second pole piece 222 in the second direction Y are both located as a whole within the thickened portion 212.

[0195] In this embodiment, the projection of the second thinned area 2221b of the second pole piece 222 in the second direction Y is set as a whole to be located within the thickened portion 212, so that the thickened portion 212 is a structure that covers the second thinned area 2221b of the second pole piece 222 in the second direction Y, thereby enabling the thickened portion 212 to constrain and restrain the overall weak structure of the second pole piece 222 in the direction in which the electrode assembly 22 expands more, so as to alleviate the phenomenon that the second thinned area 2221b of the second pole piece 222 is bent or deformed or the gap becomes larger due to excessive expansion space, which is beneficial to further alleviate the phenomenon of poor electrolyte infiltration of the electrode assembly 22 during use.

[0196] According to some embodiments of the present application, referring to Fig. 9 , Fig. 9 The cross-sectional view of the battery cell 20 provided in some embodiments of the present application. Along the second direction Y, the housing 21 has two first walls 2132a arranged opposite to each other, the two first walls 2132a are respectively located on both sides of the electrode assembly 22, and the surfaces of the two first walls 2132a facing the electrode assembly 22 are both provided with thickened portions 212.

[0197] In which, along the second direction Y, the outer shell 21 has two first walls 2132a arranged opposite to each other, that is, the outer shell 21 has two first walls 2132a in the second direction Y, and the two first walls 2132a are respectively located on both sides of the electrode assembly 22 in the second direction Y, that is, the electrode assembly 22 is located between the two first walls 2132a in the second direction Y.

[0198] The surfaces of the two first walls 2132a facing the electrode assembly 22 are both provided with a thickened portion 212, that is, the surfaces of the two first walls 2132a on the sides facing each other are both protruding with a thickened portion 212, so that the thickened portions 212 of the two first walls 2132a are facing each other in the second direction Y, so that the electrode assembly 22 is provided with a thickened portion 212 on both sides in the second direction Y.

[0199] In this embodiment, the outer shell 21 has two first walls 2132a that are relatively arranged in the second direction Y, and the two first walls 2132a are respectively located on both sides of the electrode assembly 22, and the two first walls 2132a are both provided with thickened portions 212 on the surface of the side facing the electrode assembly 22. The battery cell 20 adopting this structure can achieve abutment against the areas where the first pole piece 221 of the electrode assembly 22 forms a weak structure on both sides in the direction of greater expansion of the electrode assembly 22, which is beneficial to enhancing the effect of restraining and binding the areas where the first pole piece 221 of the electrode assembly 22 forms a weak structure through the thickened portion 212 of the outer shell 21.

[0200] According to some embodiments of the present application, see Figure 7 As shown, the electrode assembly 22 is a winding structure, the first electrode plate 221 and the second electrode plate 222 are stacked on each other and wound around an axis extending along the first direction X, so that the electrode assembly 22 forms a straight area 224 and two bending areas 225 connected to the two ends of the straight area 224 in the third direction Z, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0201] In this embodiment, the electrode assembly 22 is set to a winding structure formed by winding the first pole piece 221 and the second pole piece 222 around an axis extending along the first direction X, so that the electrode assembly 22 forms a straight area 224 between two bending areas 225, in which the first pole piece 221 and the second pole piece 222 are stacked on each other along the second direction Y. The structure is simple and easy to manufacture.

[0202] It should be noted that, in some embodiments, when the electrode assembly 22 is a wound structure, the thickened portion 212 may also be an annular structure, and the thickened portion 212 surrounds the outer side of the electrode assembly 22 around the axis extending along the first direction X. That is, if the thickened portion 212 is an embodiment in which the thickened portion 212 is convexly disposed on the surface of the side wall 2132 of the shell 213 facing the electrode assembly 22, the thickened portion 212 is an annular structure extending along the circumference of the side wall 2132.

[0203] In this embodiment, by setting the thickened portion 212 as an annular structure surrounding the outer side of the electrode assembly 22, the thickened portion 212 can not only constrain and restrain the first thinned area 2211b of the first pole piece 221 in the straight area 224 of the electrode assembly 22, but also constrain and restrain the first thinned area 2211b of the first pole piece 221 in the bending area 225 of the electrode assembly 22, which is beneficial to further alleviate the phenomenon of bending deformation or enlarged gap in the first thinned area 2211b of the first pole piece 221 during use, so as to reduce the risk of poor electrolyte infiltration of the electrode assembly 22 during use.

[0204] According to some embodiments of the present application, see Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the housing 21 may include a housing 213 and an end cap 214. The housing 213 includes a bottom wall 2131 and a side wall 2132. The side wall 2132 is arranged around the bottom wall 2131. Along the first direction X, one end of the side wall 2132 is connected to the bottom wall 2131, and the other end is enclosed to form an opening 2111. The side wall 2132 and the bottom wall 2131 jointly define the accommodating cavity 211. The end cap 214 closes the opening 2111. The thickened portion 212 is arranged on the surface of the side wall 2132 facing the electrode assembly 22.

[0205] Exemplarily, the side wall 2132 and the bottom wall 2131 of the housing 213 are integrally formed structures, that is, the side wall 2132 and the bottom wall 2131 of the housing 213 are integrally formed structures, that is, the side wall 2132 and the bottom wall 2131 of the housing 213 are formed by an integral forming process, such as stamping, casting, etc. Of course, in other embodiments, the side wall 2132 and the bottom wall 2131 of the housing 213 may also be separately arranged structures, and the bottom wall 2131 and the side wall 2132 may be connected to each other by welding, bonding, etc.

[0206] The end cover 214 closes the opening 2111 , that is, the end cover 214 is connected to one end of the housing 213 provided with the opening 2111 , and the end cover 214 covers the opening 2111 .

[0207] In this embodiment, by setting the opening 2111 of the shell 213 to be located at one end of the shell 213 in the first direction X, the end cover 214 and the bottom wall 2131 of the shell 213 are structures arranged along the first direction X, and the thickened portion 212 is arranged on the surface of the side wall 2132 facing the electrode assembly 22. On the one hand, it is convenient to assemble the electrode assembly 22 into the shell 213 along the first direction X, so that the thickened portion 212 protruding from the side wall 2132 corresponds to the thinned area of ​​the first pole piece 221, which is beneficial to reduce the difficulty of assembling the battery cell 20. On the other hand, it can reduce the difficulty of protruding the thickened portion 212 on the cavity wall surface of the accommodating cavity 211 of the shell 21.

[0208] In some embodiments, please see Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the side wall 2132 includes two first walls 2132a and two second walls 2132b, the two first walls 2132a are arranged opposite to each other along the second direction Y, the two second walls 2132b are arranged opposite to each other along the third direction Z, one first wall 2132a, one second wall 2132b, another first wall 2132a and another second wall 2132b are connected end to end in sequence, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other. The area of ​​the surface of the first wall 2132a facing away from the electrode assembly 22 is the largest surface among the outer surfaces of the battery cell 20, and the surface of the first wall 2132a facing the electrode assembly 22 is provided with a thickened portion 212.

[0209] Among them, the side wall 2132 includes two first walls 2132a and two second walls 2132b, the two first walls 2132a are relatively arranged along the second direction Y, and the two second walls 2132b are relatively arranged along the third direction Z. That is to say, the side wall 2132 of the shell 213 is a rectangular structure, so that the side wall 2132 has two opposite first walls 2132a in the second direction Y, and the side wall 2132 has two opposite second walls 2132b in the third direction Z.

[0210] The surface area of ​​the first wall 2132a facing away from the electrode assembly 22 is the largest surface among the outer surfaces of the battery cell 20, that is, the surface of the first wall 2132a facing away from the electrode assembly 22 is the large surface of the outer shell 21 of the battery cell 20. Similarly, the thickness direction of the first wall 2132a is the thickness direction of the battery cell 20, that is, the thickness direction of the battery cell 20 is the second direction Y.

[0211] In this embodiment, the side wall 2132 of the shell 213 includes two first walls 2132a arranged opposite to each other along the second direction Y and two second walls 2132b arranged opposite to each other along the third direction Z, so that the side wall 2132 has a rectangular parallelepiped structure, and the thickened portion 212 is arranged on the surface of the first wall 2132a facing the electrode assembly 22, and the outer surface of the first wall 2132a facing away from the electrode assembly 22 is the surface with the largest area among the outer surfaces of the battery cell 20, so that the thickened portion 212 is located at the electrode assembly 22 in the thickness direction of the battery cell 20. On one side, the battery cell 20 adopting this structure can constrain and restrain the area with a weak structure of the first pole piece 221 of the electrode assembly 22 in the direction of greater expansion, thereby alleviating the phenomenon of excessive gap or bending of the first pole piece 221 after expansion of the electrode assembly 22, and further reducing the phenomenon of poor electrolyte infiltration effect of the electrode assembly 22 during later use, thereby reducing the risk of lithium plating of the electrode assembly 22, and alleviating the phenomenon of increased internal resistance of the electrode assembly 22 during later use.

[0212] According to some embodiments of the present application, see Figure 7 As shown, the first electrode 221 is the negative electrode of the electrode assembly 22, and correspondingly, the second electrode 222 is the positive electrode. Of course, in other embodiments, the first electrode 221 can also be the positive electrode, and correspondingly, the second electrode 222 is the negative electrode.

[0213] For example, in Figure 7 In the embodiment, the first electrode sheet 221 is a negative electrode sheet, and the outermost electrode sheet of the electrode assembly 22 is the first electrode sheet 221 .

[0214] In this embodiment, by setting the first pole piece 221 as the negative pole piece of the electrode assembly 22, the outermost side of the electrode assembly 22 is the first pole piece 221, so that the first thinned area 2211b of the first pole piece 221 of the electrode assembly 22 which is most susceptible to deformation can be constrained and restrained by the thickened portion 212, so as to alleviate the phenomenon that the electrolyte infiltration effect of the electrode assembly 22 deteriorates during the later use, thereby reducing the risk of lithium plating of the electrode assembly 22 and alleviating the phenomenon that the internal resistance of the electrode assembly 22 increases during the later use.

[0215] According to some embodiments of the present application, see Figure 5 and Figure 6 As shown, the thickened portion 212 is integrally formed with the housing 21. That is, the thickened portion 212 and the housing 21 are an integral structure, so that the thickened portion 212 and the housing 21 are structures made by an integral molding process, such as stamping, casting or milling.

[0216] In this embodiment, by setting the thickened portion 212 and the outer shell 21 as an integrally formed structure, it is beneficial to improve the connection strength between the thickened portion 212 and the outer shell 21, thereby improving the stability and reliability of the thickened portion 212 protruding from the cavity wall surface of the accommodating cavity 211, thereby reducing the risk of the thickened portion 212 falling off during use, which is beneficial to improving the reliability and stability of the battery cell 20.

[0217] Of course, the structure of the battery cell 20 is not limited thereto. In some embodiments, the battery cell 20 may also have other structures. For example, the thickened portion 212 is separately provided and connected to the outer shell 21 .

[0218] The thickened portion 212 may be connected to the cavity wall surface of the accommodating cavity 211 of the housing 21 by using a bonding, welding or clamping structure.

[0219] In this embodiment, by arranging the thickened portion 212 and the outer shell 21 as a separate structure, and the thickened portion 212 is connected to the cavity wall surface of the accommodating cavity 211, the battery cell 20 adopting this structure is convenient for arranging the thickened portion 212 on the cavity wall surface of the accommodating cavity 211, which is beneficial to reduce the difficulty of protruding the thickened portion 212 on the cavity wall surface of the accommodating cavity 211, and is convenient for replacing the thickened portion 212 of different thicknesses.

[0220] In some embodiments, a cavity may be formed inside the thickened portion 212. In other words, the thickened portion 212 is a hollow structure.

[0221] It should be noted that in the embodiment where a cavity is formed inside the thickened portion 212 , a supporting structure such as reinforcing ribs or reinforcing bars may also be provided in the cavity of the thickened portion 212 to enhance the structural strength and deformation resistance of the thickened portion 212 .

[0222] In this embodiment, by providing a cavity inside the thickened portion 212 , the weight of the thickened portion 212 can be reduced, thereby reducing the overall weight of the battery cell 20 , which is beneficial to improving the energy density of the battery cell 20 .

[0223] According to some embodiments of the present application, the present application further provides a battery 100 , and the battery 100 includes a battery cell 20 of any of the above solutions.

[0224] Among them, see Figure 2 As shown, the battery 100 may further include a housing 10 , in which the battery cells 20 are accommodated.

[0225] In some embodiments, the box body 10 may include a first box body 11 and a second box body 12 . The first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cells 20 .

[0226] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 can also be hollow structures both with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0227] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a cuboid. Figure 2 In the embodiment, the box body 10 is a rectangular parallelepiped structure.

[0228] Optionally, the number of battery cells 20 disposed in the box body 10 may be one or more. Figure 2 In the embodiment, a plurality of battery cells 20 are arranged in the box 10 of the battery 100, and the plurality of battery cells 20 can be connected in series, in parallel or in a mixed connection. The mixed connection means that the plurality of battery cells 20 are both connected in series and in parallel. The plurality of battery cells 20 can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the battery 100 can also be a battery module formed by first connecting the plurality of battery cells 20 in series, in parallel or in a mixed connection, and then the plurality of battery modules are connected in series, in parallel or in a mixed connection to form a whole, and then accommodated in the box 10.

[0229] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0230] It should be noted that, in some embodiments, the battery 100 may not be provided with a box 10, and the battery 100 includes a plurality of battery cells 20, and the battery 100 composed of a plurality of battery cells 20 may be directly assembled on an electrical device to provide electrical energy to the electrical device through the plurality of battery cells 20. In other words, the box 10 may be used as a part of the electrical device. Taking the vehicle 1000 as an example of the electrical device, the box 10 may be used as a part of the chassis structure of the vehicle 1000, for example, a part of the box 10 may become at least a part of the floor of the vehicle 1000, or a part of the box 10 may become at least a part of the crossbeam and longitudinal beam of the vehicle 1000.

[0231] According to some embodiments of the present application, the present application further provides an electrical device, which includes a battery cell 20 according to any of the above schemes, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0232] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0233] According to some embodiments of the present application, see Figures 3 to 8As shown, the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 22 and two electrode terminals 23. The housing 21 includes a shell 213 and an end cap 214, the shell 213 includes a bottom wall 2131 and a side wall 2132, the side wall 2132 is arranged around the bottom wall 2131, along the first direction X, one end of the side wall 2132 is connected to the bottom wall 2131, and the other end is enclosed to form an opening 2111, the side wall 2132 and the bottom wall 2131 jointly define a receiving cavity 211, and the end cap 214 closes the opening 2111. The side wall 2132 includes two first walls 2132a and two second walls 2132b, the two first walls 2132a are arranged opposite to each other along the second direction Y, and the two second walls 2132b are arranged opposite to each other along the third direction Z. One first wall 2132a, one second wall 2132b, another first wall 2132a and another second wall 2132b are connected end to end in sequence, the first direction X, the second direction Y and the third direction Z are perpendicular to each other, and the area of ​​the surface of the first wall 2132a facing away from the electrode assembly 22 is the surface with the largest area among the outer surfaces of the battery cell 20. The electrode assembly 22 is accommodated in the accommodating cavity 211, and the electrode assembly 22 includes a first electrode plate 221, a second electrode plate 222 and an isolating member 223. The polarities of the first electrode plate 221 and the second electrode plate 222 are opposite. The first electrode plate 221 is a negative electrode plate, and the second electrode plate 222 is a positive electrode plate. The isolating member 223 is arranged between the first electrode plate 221 and the second electrode plate 222 to insulate and separate the first electrode plate 221 and the second electrode plate 222. The first electrode plate 221, the second electrode plate 222 and the isolating member 223 are wound to form an electrode assembly 22 with a wound structure, so that the electrode assembly 22 is formed with a straight area 224 and two bending areas 225 connected to the two ends of the straight area 224 in the third direction Z, and the portion of the first electrode plate 221 in the straight area 224 and the portion of the second electrode plate 222 in the straight area 224 are stacked along the second direction Y. The first pole piece 221 includes a first main body portion 2211 and a first pole ear 2212. The first main body portion 2211 is formed with a first main body area 2211a and a first thinned area 2211b arranged along the first direction X. The thickness of the first thinned area 2211b is less than the thickness of the first main body area 2211a. The first pole ear 2212 is connected to one end of the first thinned area 2211b away from the first main body area 2211a in the first direction X. The second pole piece 222 includes a second main body portion 2221 and a second pole ear 2222. The second main body portion 2221 is formed with a second main body area 2221a and a second thinned area 2221b arranged along the first direction X. The thickness of the second thinned area 2221b is less than the thickness of the second main body area 2221a. Along the first direction X, the second pole ear 2222 is connected to an end of the second thinned area 2221b away from the second main body area 2221a, and the second pole ear 2222 and the first pole ear 2212 are located at the same end of the electrode assembly 22.The two electrode terminals 23 are both arranged on the end cover 214, one of the two electrode terminals 23 is electrically connected to the first pole ear 2212, and the other electrode terminal 23 is electrically connected to the second pole ear 2222, so as to input or output the electric energy of the battery cell 20. Among them, a thickened portion 212 is convexly provided on the surface of the first wall 2132a facing the electrode assembly 22, and the thickened portion 212 is integrally formed with the shell 21. Along the second direction Y, the projection of the first thinned area 2211b is entirely located in the thickened portion 212, and the projection of the second thinned area 2221b is entirely located in the thickened portion 212. Along the first direction X, both ends of the thickened portion 212 exceed the first thinned area 2211b and the second thinned area 2221b, the length of the thickened portion 212 is less than or equal to twice the length of the first thinned area 2211b, and the length of the thickened portion 212 is less than or equal to twice the length of the second thinned area 2221b. The thickness of the thickened portion 212 protruding from the surface of the first wall 2132a facing the electrode assembly 22 is D, satisfying 0mm<D≤5mm.

[0234] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0235] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving cavity formed therein; as well as an electrode assembly, accommodated in the accommodation cavity, the electrode assembly comprising a first electrode piece, the first electrode piece comprising a first main body portion and a first electrode tab, the first main body portion being formed with a first main body region and a first thinned region arranged along a first direction, the thickness of the first thinned region being smaller than the thickness of the first main body region, and the first electrode tab being connected to an end of the first thinned region away from the first main body region in the first direction; A thickened portion is convexly provided on the wall surface of the accommodating cavity, and along the thickness direction of the first thinned area, at least part of the projection of the first thinned area is located in the thickened portion, and the thickness direction of the first thinned area is perpendicular to the first direction.

2. The battery cell according to claim 1, characterized in that: Along the first direction, at least one end of the thickened portion exceeds the first thinned area.

3. The battery cell according to claim 2, characterized in that: Along the first direction, both ends of the thickened portion exceed the first thinned area.

4. The battery cell according to claim 1, characterized in that: Along the first direction, the length of the thickened portion is less than or equal to twice the length of the first thinned area.

5. The battery cell according to claim 1, characterized in that: The thickness of the thickened portion protruding from the cavity wall of the accommodating cavity is D, satisfying 0mm<D≤5mm.

6. The battery cell according to claim 1, characterized in that: The electrode assembly further comprises: A second pole piece, having a polarity opposite to that of the first pole piece, the second pole piece comprising a second main body portion and a second pole ear, the second main body portion being formed with a second main body region and a second thinned region arranged along the first direction, the thickness of the second thinned region being smaller than the thickness of the second main body region, the second pole ear being connected to an end of the second thinned region away from the second main body region along the first direction, and the second pole ear and the first pole ear being located at the same end of the electrode assembly; Wherein, along the thickness direction of the second thinned area, at least a part of the projection of the second thinned area is located in the thickened portion, and the thickness direction of the second thinned area is perpendicular to the first direction.

7. The battery cell according to claim 6, characterized in that: Along the first direction, at least one end of the thickened portion exceeds the second thinned area.

8. The battery cell according to claim 7, characterized in that: Along the first direction, both ends of the thickened portion exceed the second thinned area.

9. The battery cell according to claim 6, characterized in that: Along the first direction, a length of the thickened portion is less than or equal to twice a length of the second thinned region.

10. The battery cell according to claim 6, characterized in that: Along a thickness direction of the first thinned region, projections of the first thinned region and the second thinned region at least partially overlap.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The electrode assembly is formed with a straight region, and the electrode assembly further comprises a second pole piece having a polarity opposite to that of the first pole piece; Part of the first pole piece in the straight area and part of the second pole piece in the straight area are stacked along a second direction, along the second direction, the outer shell has a first wall arranged opposite to the electrode assembly, the thickened portion is arranged on the surface of the first wall facing the electrode assembly, and the second direction is perpendicular to the first direction.

12. The battery cell according to claim 11, characterized in that: Along the second direction, the projection of the first thinned area is entirely located within the thickened portion.

13. The battery cell according to claim 11, characterized in that: The second pole piece includes a second main body and a second pole ear, the second main body is formed with a second main area and a second thinned area arranged along the first direction, the thickness of the second thinned area is less than the thickness of the second main area, along the first direction, the second pole ear is connected to an end of the second thinned area away from the second main area, and the second pole ear and the first pole ear are located at the same end of the electrode assembly; Wherein, along the second direction, the projection of the second thinned area is entirely located within the thickened portion.

14. The battery cell according to claim 11, characterized in that: Along the second direction, the shell has two first walls arranged opposite to each other, the two first walls are respectively located on both sides of the electrode assembly, and the thickened portion is provided on surfaces of the two first walls facing the electrode assembly.

15. The battery cell according to claim 11, characterized in that: The electrode assembly is a wound structure, the first pole piece and the second pole piece are stacked on each other and wound around an axis extending along the first direction, so that the electrode assembly forms the straight area and two bending areas connected to the two ends of the straight area in the third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

16. The battery cell according to claim 15, characterized in that: The thickened portion is an annular structure, and the thickened portion surrounds the outer side of the electrode assembly around an axis extending along the first direction.

17. The battery cell according to claim 1, characterized in that: The housing comprises: A housing, comprising a bottom wall and a side wall, wherein the side wall is disposed around the bottom wall, and along the first direction, one end of the side wall is connected to the bottom wall, and the other end is enclosed to form an opening, and the side wall and the bottom wall jointly define the accommodating cavity; an end cap for closing the opening; Wherein, the thickened portion is arranged on the surface of the side wall facing the electrode assembly.

18. The battery cell according to claim 17, characterized in that: The side wall comprises two first walls and two second walls, the two first walls are arranged opposite to each other along the second direction, the two second walls are arranged opposite to each other along the third direction, one first wall, one second wall, another first wall and another second wall are connected end to end in sequence, and the first direction, the second direction and the third direction are perpendicular to each other; The area of ​​the surface of the first wall facing away from the electrode assembly is the largest surface among the outer surfaces of the battery cell, and the thickened portion is provided on the surface of the first wall facing the electrode assembly.

19. The battery cell according to claim 1, characterized in that: The first electrode sheet is the negative electrode sheet of the electrode assembly.

20. The battery cell according to claim 1, characterized in that The thickened portion is integrally formed with the shell.

21. The battery cell according to claim 1, characterized in that: The thickened portion is separately arranged and connected to the outer shell.

22. The battery cell according to claim 1, characterized in that: A cavity is formed inside the thickened portion.

23. A battery, characterized in that: Comprising the battery cell according to any one of claims 1 to 22.

24. An electrical device, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 22, wherein the battery cell is used to provide electrical energy.

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