Battery cell, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, the battery monomer comprises an electrode assembly and a shell, the electrode assembly is accommodated in the shell, the electrode assembly comprises a winding part and a lamination part, and the winding part is wound on the peripheral side of the lamination part; the peripheral surface of the winding part comprises an arc-shaped surface, two first planes opposite to each other in the first direction and two second planes opposite to each other in the second direction, the arc-shaped surface is connected with the adjacent first planes and second planes, and the first direction, the second direction and the winding center line of the winding part are perpendicular to each other. According to the battery monomer provided by the invention, the gap between the electrode assembly and the shell is reduced, and the space, occupied by the electrode assembly, in the battery monomer is increased, so that the group margin and the energy density of the battery monomer are improved, and the electrolyte injection smoothness of the battery monomer is improved.

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] Battery monomers are widely used in electronic devices, such as mobile phones, laptop computers, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] In the development of battery cell technology, in addition to improving the performance of battery cells, how to improve the energy density of battery cells is also an issue that needs to be considered. Therefore, how to improve the energy density of battery cells is an issue of continuous improvement in battery cell technology. Utility Model Content

[0004] The present application provides a battery cell, a battery, and an electrical device to improve the energy density of the battery cell.

[0005] This application is achieved through the following technical solutions:

[0006] In the first aspect, an embodiment of the present application provides a battery cell, the battery cell includes a shell and an electrode assembly, the electrode assembly is accommodated in the shell, the electrode assembly includes a winding portion and a stacked portion, the winding portion is wound around the outer peripheral side of the stacked portion; the outer peripheral surface of the winding portion includes an arcuate surface, two first planes opposite to each other in a first direction, and two second planes opposite to each other in a second direction, the arcuate surface connects adjacent first planes and second planes, and the first direction, the second direction and the winding center line of the winding portion are perpendicular to each other.

[0007] According to the battery cell provided in the embodiment of the present application, the electrode assembly includes a winding portion and a lamination portion, and the winding portion is wound on the outer peripheral side of the lamination portion, so that the outer peripheral surface of the winding portion of the electrode assembly includes a first plane opposite to each other in a first direction and a second plane opposite to each other in a second direction, and an arc surface connecting the adjacent first plane and second plane. In this way, it is beneficial to reduce the gap between the electrode assembly and the shell, increase the space inside the battery cell occupied by the electrode assembly, and further improve the group margin and energy density of the battery cell. In addition, there is a gap between the winding portion and the lamination portion of the electrode assembly. In the process of injecting electrolyte into the battery cell, the gap between the winding portion and the lamination portion is beneficial to improve the smoothness of electrolyte injection.

[0008] According to some embodiments of the present application, the radius of curvature r of the arcuate surface satisfies: 2mm≤r≤8mm.

[0009] In the above scheme, setting 2mm≤r≤8mm is beneficial to improving the energy density of the battery cell while facilitating the preparation of the electrode assembly and reducing the process difficulty of preparing the electrode assembly.

[0010] According to some embodiments of the present application, 3mm≤r≤5mm.

[0011] In the above scheme, setting 3mm≤r≤5mm is beneficial to further improve the energy density of the battery cell, while further facilitating the preparation of the electrode assembly and further reducing the process difficulty of preparing the electrode assembly.

[0012] According to some embodiments of the present application, the stacking portion includes a first positive electrode sheet and a first negative electrode sheet, the winding portion includes a second positive electrode sheet and a second negative electrode sheet, the second positive electrode sheet and the second negative electrode sheet are alternately wound in layers, the first positive electrode sheet and the first negative electrode sheet are alternately arranged in layers along the first direction, and any two layers of the first positive electrode sheets are disconnected from each other.

[0013] In the above scheme, the first positive electrode sheets of the stacking part are arranged alternately in layers along the first direction, and the first positive electrode sheets of any two layers are disconnected from each other, which is beneficial to reducing the process difficulty in the preparation process of the electrode assembly, reducing the risk of the active material layer on the first positive electrode sheet of the stacking part falling off, and reducing the risk of lithium deposition in the electrode assembly.

[0014] According to some embodiments of the present application, the number of layers of the first positive electrode sheets along the first direction is n, the number of layers of the second positive electrode sheets along the first direction is m, and 20%≤n / (m+n)≤80%.

[0015] In the above scheme, setting 20%≤n / (m+n)≤80% is beneficial to fully utilize the space inside the shell of the battery cell and improve the energy density of the battery cell when the electrode assembly is applied to the battery cell.

[0016] According to some embodiments of the present application, 33%≤n / (m+n)≤55%.

[0017] In the above scheme, setting 33%≤n / (m+n)≤55% is beneficial to further fully utilize the space inside the shell of the battery cell and further improve the energy density of the battery cell when the electrode assembly is applied to the battery cell.

[0018] According to some embodiments of the present application, a dimension of the electrode assembly along the first direction is smaller than a dimension along the second direction, and a dimension a of the second plane along the first direction satisfies: a≥5 mm.

[0019] In the above scheme, setting a≥5mm is beneficial to reducing the process difficulty of electrode assembly processing while improving the energy density of the battery cell.

[0020] According to some embodiments of the present application, the electrode assembly includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes the first positive electrode sheet and the second positive electrode sheet, the negative electrode sheet includes the second positive electrode sheet and the second negative electrode sheet, along the first direction, the positive electrode sheets and the negative electrode sheets are alternately arranged in layers, and the outermost circle of the winding portion is the second negative electrode sheet.

[0021] In the above scheme, for lithium-ion battery cells, when the electrode assembly is working, the lithium ions released from the positive electrode sheet are always received by the negative electrode sheet, which is beneficial to reduce the risk of lithium deposition in the electrode assembly.

[0022] According to some embodiments of the present application, the first negative electrode sheet is wound around the first positive electrode sheet, the first negative electrode sheet includes a first laminate sub-segment and a first bent sub-segment, the first laminate sub-segment and the first positive electrode sheet are stacked along the first direction, and the first bent sub-segment connects the same end of two layers of the first laminate sub-segments along the second direction.

[0023] In the above scheme, the first bending sub-segment of the first negative electrode sheet has a larger radius of curvature, which is beneficial to reducing the risk of the active material layer of the first negative electrode sheet falling off during the winding process of the first negative electrode sheet, thereby helping to improve the reliability of the electrode assembly.

[0024] According to some embodiments of the present application, the first negative electrode sheet includes a second bent sub-segment and a second laminate sub-segment, the second laminate sub-segments and the first positive electrode sheet are alternately arranged in layers, and the second bent sub-segment connects the same end of two adjacent layers of the second laminate sub-segments along the second direction so that the first negative electrode sheet is reciprocatingly bent.

[0025] In the above scheme, the stacked parts are arranged more closely, and there is a larger gap between the stacked parts and the winding parts on both sides along the second direction. During the process of injecting electrolyte into the battery cells, the gap can be used to inject electrolyte, which is beneficial to improving the efficiency of electrolyte injection into the battery cells.

[0026] In a second aspect, the battery provided in the embodiments of the present application includes the battery cell provided in any of the above embodiments.

[0027] The battery provided in the embodiment of the present application has the same technical effect as the battery cell provided in any of the above embodiments, and thus will not be described in detail here.

[0028] According to some embodiments of the present application, the housing is in a quadrangular prism shape, the battery further includes a first battery cell, the first battery cell is in a cylindrical shape, and any of the first battery cells is disposed adjacent to the battery cell.

[0029] In the above scheme, the battery includes a first battery cell and a battery cell, and the first battery cell is arranged adjacent to the battery cell. The gap formed between the two can be used to dissipate heat from the battery cell, which is beneficial to reducing the risk of thermal runaway of the battery.

[0030] According to some embodiments of the present application, the size of the shell along the first direction is equal to the size along the second direction, the diameter of the first battery cell is smaller than or equal to the size of the shell along the first direction, and the first battery cell is adjacent to the battery cell on both sides along the first direction and both sides along the second direction.

[0031] In the above scheme, the size of the shell along the first direction is set to be equal to the size along the second direction, and the first battery cell is set to be adjacent to the battery cell on both sides along the first direction and the second direction. This is beneficial to improving the heat dissipation efficiency of the battery and reducing the risk of thermal runaway of the battery while improving the energy density of the battery.

[0032] According to some embodiments of the present application, the battery also includes a second battery cell, which is in the shape of a quadrangular prism, the size of the second battery cell along the second direction is larger than the size along the first direction, and a plurality of the second battery cells are arranged at intervals along at least the first direction; the battery cell is in the shape of a quadrangular prism, and at least one side of the second battery cell along the first direction is provided with n battery cells arranged at intervals along the second direction, wherein n≥2, and n is a positive integer.

[0033] In the above scheme, it is beneficial to improve the heat dissipation efficiency of the battery and reduce the risk of thermal runaway of the battery while improving the energy density of the battery.

[0034] In a third aspect, the electrical device provided in the embodiments of the present application includes the battery provided in any of the above embodiments, and the battery is used to provide electrical energy.

[0035] The electric device provided in the embodiment of the present application has the same technical effect as the battery provided in any of the above embodiments, and thus will not be described in detail here.

[0036] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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.

[0038] Figure 1 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application;

[0039] Figure 2 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of the structure of a battery module in a battery provided in an embodiment of the present application;

[0041] Figure 4 A schematic diagram of the explosion structure of a battery cell provided in an embodiment of the present application;

[0042] Figure 5 A front view of an electrode assembly in a battery cell provided in an embodiment of the present application;

[0043] Figure 6 A schematic diagram of the structure of an electrode assembly in a battery cell provided in an embodiment of the present application;

[0044] Figure 7 Another schematic diagram of the structure of an electrode assembly in a battery cell provided in an embodiment of the present application;

[0045] Figure 8 A schematic diagram of the structure of the positive electrode sheet of the electrode assembly in the battery cell provided in the embodiment of the present application after unfolding;

[0046] Fig. 9 Another structural schematic diagram of the positive electrode sheet of the electrode assembly in the battery cell provided in the embodiment of the present application after unfolding;

[0047] Fig.10 A schematic diagram of the structure of another battery provided in an embodiment of the present application;

[0048] Fig.11 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0049] Fig.12 A schematic diagram of the structure of another battery provided in an embodiment of the present application.

[0050] In the drawings, the figures are not necessarily drawn to scale.

[0051] Description of reference numerals:

[0052] 1. Vehicle; 1a. Motor; 1b. Controller;

[0053] 10. battery; 11. housing; 111. first sub-housing; 112. second sub-housing;

[0054] 20. Battery module;

[0055] 30. Battery cell; 31. Casing; 311. Shell; 312. End cover;

[0056] 40. electrode assembly; 41. winding portion; 41a. first plane; 41b. second plane; 41c. arcuate surface; 411. second positive electrode sheet; 412. second negative electrode sheet; 42. lamination portion; 421. first positive electrode sheet; 422. first negative electrode sheet; 4221. first lamination sub-segment; 4222. first bending sub-segment; 422a. second lamination sub-segment; 422b. second bending sub-segment; 40a. positive electrode sheet; 40b. negative electrode sheet;

[0057] 50. a first battery cell; 60. a second battery cell;

[0058] X, first direction; Y, second direction. DETAILED DESCRIPTION

[0059] 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 and completely 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.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning 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.

[0061] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations 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. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0062] 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.

[0063] 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.

[0064] The term "multiple" as used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0065] 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.

[0066] 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.

[0067] 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.

[0068] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0069] 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.

[0070] The battery cells may be, but are not limited to, lithium ion batteries, sodium ion batteries, sodium lithium ion batteries, lithium metal batteries, sodium metal batteries, lithium sulfur batteries, magnesium ion batteries, nickel hydrogen batteries, nickel cadmium batteries, lead storage batteries, etc.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium with surface silver plating can 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.).

[0075] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.

[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 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.

[0078] In some embodiments, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode active material is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0079] As an example, the negative electrode active material may adopt the negative electrode active material for the battery 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 and 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.

[0080] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0081] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without special restrictions. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without special restrictions. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surface of the positive and negative electrodes.

[0082] 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.

[0083] 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.

[0084] In some embodiments, the housing includes an end cap and a shell, the shell is provided with an opening, and the end cap closes the opening to form a closed space for accommodating substances such as the electrode assembly and the electrolyte. The shell may be provided with one or more openings. One or more end caps may also be provided.

[0085] In some embodiments, at least one electrode terminal is disposed on the housing, and the electrode terminal is electrically connected to the electrode tab of the electrode assembly. The electrode terminal may be directly connected to the electrode tab, or may be indirectly connected to the electrode tab through an adapter. The electrode terminal may be disposed on the end cap, or may be disposed on the housing.

[0086] In some embodiments, an explosion-proof valve is provided on the housing, and the explosion-proof valve is used to release the internal pressure of the battery cell.

[0087] As an example, the battery cell can 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 a square shell battery cell, a blade-shaped battery cell, a polygonal prismatic battery, such as a hexagonal prismatic battery, etc. There is no particular limitation in the embodiments of the present application.

[0088] The electrode assembly of a battery cell is a key component for energy storage and release of the battery cell. The electrode assembly usually includes a positive electrode sheet and a negative electrode sheet. In related technologies, the positive electrode sheet and the negative electrode sheet are usually formed into a winding structure by a simple winding method.

[0089] However, a simple wound electrode assembly will form an arc-shaped area on the outer surface of the electrode assembly after winding, and there is a large gap between the arc-shaped area and the battery shell, resulting in a waste of space inside the shell. In addition, during the winding process of the positive and negative electrode sheets of the electrode assembly, one side of the innermost negative electrode sheet is not used. Thus, a single-threaded wound electrode assembly is not conducive to improving the energy density of the battery cell.

[0090] In view of this, an embodiment of the present application provides a battery cell, the battery cell includes a shell and an electrode assembly, the electrode assembly is accommodated in the shell, the electrode assembly includes a winding portion and a laminate portion, the winding portion is wound around the outer peripheral side of the laminate portion. The outer peripheral surface of the winding portion includes an arcuate surface c, two first planes opposite to each other along a first direction, and two second planes opposite to each other along a second direction, the arcuate surface c connects the adjacent first planes and the second planes, and the first direction, the second direction and the winding center line of the winding portion are perpendicular to each other.

[0091] The battery cell provided in the embodiment of the present application is provided with an electrode assembly including a winding portion and a lamination portion, and the winding portion is wound on the outer peripheral side of the lamination portion, so that the outer peripheral surface of the winding portion of the electrode assembly includes a first plane opposite to each other in a first direction and a second plane opposite to each other in a second direction, and an arc surface connecting the adjacent first plane and second plane. In this way, when the electrode assembly is applied to the battery cell, it is beneficial to reduce the gap between the electrode assembly and the shell, increase the space inside the battery cell occupied by the electrode assembly, and further help to improve the energy density of the battery cell. In addition, there is a large gap between the winding portion and the lamination portion of the electrode assembly, which is beneficial to improve the smoothness of electrolyte injection during the process of injecting electrolyte into the battery cell.

[0092] The technical solution provided in the embodiments of the present application is applicable to battery cells, batteries including battery cells, and electrical devices using battery cells.

[0093] The battery disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. The battery disclosed in the present application can be used to form a power supply system of the electrical device.

[0094] 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 computer, a laptop computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0095] For the convenience of description, the following embodiments are described by taking a vehicle 1 as an example of an electrical device in an embodiment of the present application.

[0096] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1 provided for some embodiments of the present application. The vehicle 1 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 10 is provided inside the vehicle 1, and the battery 10 may be provided at the bottom, the head or the tail of the vehicle 1. The battery 10 may be used to power the vehicle 1, for example, the battery 10 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the startup, navigation and operation of the vehicle 1.

[0097] The vehicle 1 may further include a controller 1b and a motor 1a, wherein the controller 1b is used to control the battery 10 to supply power to the motor 1a, for example, to meet the power requirements of starting, navigating, and driving the vehicle 1.

[0098] In some embodiments of the present application, the battery 10 can be used not only as an operating power source for the vehicle 1 , but also as a driving power source for the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .

[0099] Please refer to Figure 2 and Figure 3 , Figure 2 An exploded view of a battery 10 provided in some embodiments of the present application, Figure 3Schematic diagram of the structure of the battery module 20 in the battery 10 provided in an embodiment of the present application. The battery 10 includes a case 11 and a battery cell 30, and the battery cell 30 is accommodated in the case 11. Among them, the case 11 is used to provide a storage space for the battery cell 30, and the case 11 can adopt a variety of structures. In some embodiments, the case 11 may include a first sub-case 111 and a second sub-case 112, the first sub-case 111 and the second sub-case 112 cover each other, and the first sub-case 111 and the second sub-case 112 jointly define a storage space for accommodating the battery cell 30. The second sub-box 112 may be a hollow structure with one end open, and the first sub-box 111 may be a plate-like structure, and the first sub-box 111 covers the open side of the second sub-box 112, so that the first sub-box 111 and the second sub-box 112 jointly define a storage space; the first sub-box 111 and the second sub-box 112 may also be hollow structures both with one side open, and the open side of the first sub-box 111 covers the open side of the second sub-box 112.

[0100] In the battery 10, there may be multiple battery cells 30, and the multiple battery cells 30 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 30 are both connected in series and in parallel. The multiple battery cells 30 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 30 is accommodated in the box 11; of course, the battery 10 may also be a battery module 20 in the form of multiple battery cells 30 connected in series, in parallel, or in a mixed connection, and then the multiple battery modules 20 are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 11. The battery 10 may also include other structures, for example, the battery 10 may also include a busbar component for realizing electrical connection between the multiple battery cells 30.

[0101] The battery cell 30 may be a secondary battery or a primary battery; the battery cell 30 may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.

[0102] Please refer to Figure 4 , Figure 4 Exploded diagram of a battery cell 30 provided in some embodiments of the present application. Figure 4 As shown, the battery cell 30 includes a housing 31, an electrode assembly 40 and electrode terminals. The housing 31 includes a shell 311 and an end cap 312. The shell 311 has an opening, and the end cap 312 closes the opening to isolate the internal environment of the battery cell 30 from the external environment.

[0103] The shell 311 is a component used to cooperate with the end cap 312 to form the internal environment of the battery cell 30, wherein the formed internal environment can be used to accommodate the electrode assembly 40, the electrolyte and other components. The shell 311 and the end cap 312 can be independent components. The shell 311 can be of various shapes and sizes. Specifically, the shape of the shell 311 can be determined according to the specific shape and size of the electrode assembly 40. The material of the shell 311 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0104] The end cap 312 refers to a component that covers the opening of the shell 311 to isolate the internal environment of the battery cell 30 from the external environment. Without limitation, the shape of the end cap 312 can be adapted to the shape of the shell 311 to match the shell 311. Optionally, the end cap 312 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 312 is not easily deformed when squeezed and collided, so that the battery cell 30 can have a higher structural strength and reliability can also be improved. Functional components such as electrode terminals can be provided on the end cap 312. The electrode terminal can be used to electrically connect to the electrode assembly 40 for outputting or inputting electrical energy of the battery cell 30. The material of the end cap 312 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose special restrictions on this. In some embodiments, an insulating structure can also be provided on the inner side of the end cap 312, and the insulating structure can be used to isolate the electrical connection components in the shell 311 from the end cap 312 to reduce the risk of short circuit. Exemplarily, the insulating structure may be plastic, rubber, or the like.

[0105] The electrode assembly 40 is a component in the battery cell 30 where an electrochemical reaction occurs. One or more electrode assemblies 40 may be included in the housing 311. The electrode assembly 40 is mainly formed by winding or stacking a positive electrode sheet 40a and a negative electrode sheet 40b, and a separator is usually provided between the positive electrode sheet 40a and the negative electrode sheet 40b, and the separator is used to separate the positive electrode sheet 40a and the negative electrode sheet 40b to avoid short circuits between the positive electrode sheet 40a and the negative electrode sheet 40b. The parts of the positive electrode sheet 40a and the negative electrode sheet 40b with active materials constitute the electrode body of the electrode assembly 40, and the parts of the positive electrode sheet 40a and the negative electrode sheet 40b without active materials each constitute a pole ear. The positive pole ear and the negative pole ear may be located at one end of the electrode body together or at both ends of the electrode body respectively. During the charge and discharge process of the battery cell 30, the positive active material and the negative active material react with the electrolyte, and the pole ear connects the electrode terminal to form a current loop.

[0106] First, as Figure 4 , Figure 5 , Figure 6 and Figure 7As shown, the embodiment of the present application provides a battery cell 30 including a housing 31 and an electrode assembly 40, the electrode assembly 40 is accommodated in the housing 31, the electrode assembly 40 includes a winding portion 41 and a laminate portion 42, the winding portion 41 is wound around the outer circumference of the laminate portion 42. The outer circumferential surface of the winding portion 41 includes an arcuate surface 41c, two first planes 41a opposite to each other along a first direction X, and two second planes 41b opposite to each other along a second direction Y, the arcuate surface 41c connects the adjacent first planes 41a and second planes 41b, and the first direction X, the second direction Y and the winding center line of the winding portion 41 are perpendicular to each other.

[0107] The electrode assembly 40 generally includes a positive electrode sheet 40a, a negative electrode sheet 40b, and a separator disposed between the positive electrode sheet 40a and the negative electrode sheet 40b. During operation of the electrode assembly 40, lithium ions and the like are repeatedly embedded and detached between the positive electrode sheet 40a and the negative electrode sheet 40b to achieve storage or release of electrical energy.

[0108] The electrode assembly 40 includes a stacked portion 42 and a wound portion 41 . The stacked portion 42 may include a portion of the positive electrode sheet 40 a and a portion of the negative electrode sheet 40 b , and the wound portion 41 includes another portion of the positive electrode sheet 40 a and another portion of the negative electrode sheet 40 b .

[0109] Exemplarily, the positive electrode sheet 40a may include a first positive electrode sheet 421 and a second positive electrode sheet 411, the negative electrode sheet 40b may include a first negative electrode sheet 422 and a second negative electrode sheet 412, the stacking portion 42 may include a first positive electrode sheet 421 and a first negative electrode sheet 422, and the winding portion 41 may include a second positive electrode sheet 411 and a second negative electrode sheet 412.

[0110] The lamination part 42 is stacked, then optionally, at least part of the first positive electrode sheet 421 and the first negative electrode sheet 422 of the lamination part 42 are stacked, or the first positive electrode sheet 421 and the first negative electrode sheet 422 of the lamination part 42 are stacked. Exemplarily, the first positive electrode sheet 421 of the lamination part 42 can be stacked, and the first negative electrode sheet 422 can be wound around the first positive electrode sheet 421, or the first negative electrode sheet 422 can be stacked together with the first positive electrode sheet 421. Figure 8 and Fig. 9 Two structural types of the positive electrode sheet 40a after unfolding are shown respectively.

[0111] Optionally, at least a portion of the laminated sheet portions 42 may be stacked along the first direction X, or stacked along the second direction Y.

[0112] When the first positive electrode sheets 421 of the stacking portion 42 are stacked, during the preparation of the stacking portion 42 , the stacking portion 42 can be formed by winding, and then both sides of the first positive electrode sheets 421 after winding are cut to form the stacking portion 42 .

[0113] Alternatively, when the first positive electrode sheet 421 of the stacking portion 42 is stacked and the first negative electrode sheet 422 is wound, the first negative electrode sheet 422 can be formed by winding, and then the first positive electrode sheet 421 is inserted between two adjacent wound first negative electrode sheets 422 .

[0114] That is to say, the lamination portion 42 of the electrode assembly 40 in the battery cell 30 provided in the embodiment of the present application may not need to be formed by lamination equipment, but may be formed on a winding machine, which is helpful to simplify the preparation process of the electrode assembly 40 .

[0115] The electrode assembly 40 is provided to include a stacking portion 42, and a winding portion 41 is provided to be wound on the outer peripheral side of the stacking portion 42, then the second positive electrode sheet 411 and the second negative electrode sheet 412 of the winding portion 41 are both wound on the outer peripheral side of the stacking portion 42, so that, in the process of winding the winding portion 41 outside the stacking portion 42, two opposite straight portions and an arc portion connecting the two straight portions are formed on both sides of the first direction X and both sides of the second direction Y of the stacking portion 42, and after the winding portion 41 is wound, two opposite first planes 41a, two opposite second planes 41b and an arc surface 41c connecting the first plane 41a and the second plane 41b are formed on the outer surface of the winding portion 41.

[0116] It is understandable that the first plane 41a and the second plane 41b may not be strictly absolute planes. Depending on the working condition of the electrode assembly 40, bulging or depression may occur during the operation of the electrode assembly 40. Therefore, the first plane 41a and the second plane 41b may have a concave-convex structure.

[0117] It can be understood that when at least part of the laminate portion 42 is stacked along the first direction X, during the process of winding the winding portion 41 around the laminate portion 42, due to the different structural forms of the two, there is a large gap between the two sides of the laminate portion 42 along the second direction Y and the inner surface of the winding portion 41. After the electrode assembly 40 is assembled in the outer shell 31 of the battery cell 30, during the process of injecting electrolyte into the battery cell 30, the gap can be used to inject electrolyte into the battery cell 30.

[0118] Furthermore, since the outer peripheral surface of the winding portion 41 includes an arcuate surface 41c, a first plane 41a and a second plane 41b, this is beneficial for reducing the gap between the electrode assembly 40 and the outer shell 31, thereby increasing the space inside the battery cell 30 occupied by the electrode assembly 40, and is beneficial for improving the group margin and energy density of the battery cell 30.

[0119] The battery cell 30 provided in the embodiment of the present application is provided with an electrode assembly 40 including a winding portion 41 and a lamination portion 42, and the winding portion 41 is wound on the outer peripheral side of the lamination portion 42, so that the outer peripheral surface of the winding portion 41 of the electrode assembly 40 includes a first plane 41a opposite to each other along the first direction X and a second plane 41b opposite to each other along the second direction Y, and an arc surface 41c connecting the adjacent first planes 41a and second planes 41b, so that it is beneficial to reduce the gap between the electrode assembly 40 and the housing 31, increase the space inside the battery cell 30 occupied by the electrode assembly 40, and further improve the group margin and energy density of the battery cell 30. In addition, there is a gap between the winding portion 41 and the lamination portion 42 of the electrode assembly 40. In the process of injecting electrolyte into the battery cell 30, the gap between the winding portion 41 and the lamination portion 42 is beneficial to improve the smoothness of electrolyte injection.

[0120] In some embodiments, Figure 5 As shown, the curvature radius r of the arcuate surface 41c satisfies: 2mm≤r≤8mm.

[0121] It can be understood that the electrode assembly 40 has two first surfaces and two second surfaces, and thus the electrode assembly 40 has four arcuate surfaces 41 c , and the curvature radii r of the four arcuate surfaces 41 c may be the same or different.

[0122] Optionally, r can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm or 8mm, etc.

[0123] It is understandable that the larger the curvature radius r of the arc surface 41c, the easier it is to prepare the electrode assembly 40, and the smaller the curvature radius r of the thermal arc surface 41c, the more conducive it is to reduce the gap between the electrode assembly 40 and the shell 31 and improve the energy density of the battery cell 30.

[0124] After systematic analysis and long-term practice, the inventors found that setting 2mm≤r≤8mm is beneficial to improving the energy density of the battery cell 30 while facilitating the preparation of the electrode assembly 40 and reducing the process difficulty of preparing the electrode assembly 40 .

[0125] In some embodiments, 3 mm ≤ r ≤ 5 mm.

[0126] Optionally, r can be 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc.

[0127] After further systematic analysis and long-term practice, the inventors found that setting 3mm≤r≤5mm is beneficial to further improve the energy density of the battery cell 30 while further facilitating the preparation of the electrode assembly 40 and further reducing the process difficulty of preparing the electrode assembly 40.

[0128] In some embodiments, Figure 6 and Figure 7 As shown, the lamination portion 42 includes a first positive electrode sheet 421 and a first negative electrode sheet 422, the winding portion 41 includes a second positive electrode sheet 411 and a second negative electrode sheet 412, the second positive electrode sheet 411 and the second negative electrode sheet 412 are alternately wound in layers, the first positive electrode sheet 421 and the first negative electrode sheet 422 are alternately arranged in layers along the first direction X, and any two layers of the first positive electrode sheets 421 are disconnected from each other.

[0129] Optionally, the first positive electrode sheet 421 and the second positive electrode sheet 411 may be connected to each other, or they may be disconnected from each other. Similarly, the first negative electrode sheet 422 and the second negative electrode sheet 412 may be disconnected from each other, or they may be disconnected from each other.

[0130] The first positive electrode sheet 421 and the first negative electrode sheet 422 are stacked along the first direction X, and any two layers of the first positive electrode sheets 421 are disconnected from each other, and the multiple first positive electrode sheets 421 of the laminated part 42 are disconnected from each other and stacked along the first direction X. In this way, during the preparation of the laminated part 42, the first positive electrode sheet 421 can be wound on a winding device, and then the first positive electrode sheet 421 can be sliced ​​on both sides of the second direction Y, which is conducive to simplifying the manufacturing process of the laminated part 42 and reducing the process difficulty of the laminated part 42. In addition, the first positive electrode sheet 421 does not need to be bent, which is conducive to reducing the risk of the active material layer on the first positive electrode sheet 421 falling off.

[0131] The first positive electrode sheets 421 and the first negative electrode sheets 422 are alternately arranged in layers along the first direction X, and there is only one first negative electrode sheet 422 between any two adjacent first positive electrode sheets 421 along the first direction X, and there is only one first positive electrode sheet 421 between any two connected first negative electrode sheets 422 along the first direction X. In this way, the problem of lithium deposition in the electrode assembly 40 is reduced.

[0132] Therefore, the first positive electrode sheets 421 of the stacking part 42 are arranged alternately layer by layer along the first direction X, and any two layers of the first positive electrode sheets 421 are disconnected from each other, which is beneficial to reducing the process difficulty during the preparation of the electrode assembly 40, reducing the risk of the active material layer on the first positive electrode sheets 421 of the stacking part 42 falling off, and reducing the risk of lithium deposition in the electrode assembly 40.

[0133] In some embodiments, the number of layers of the first positive electrode sheets 421 along the first direction X is n, the number of layers of the second positive electrode sheets 411 along the first direction X is m, and 20%≤n / (m+n)≤80%.

[0134] The number of layers of the first positive electrode sheet 421 along the first direction X is the number of layers of the first positive electrode sheet 421 in the lamination portion 42 stacked along the first direction X, and the number of layers of the second positive electrode sheet 411 along the first direction X may be the number of stacked layers of the second positive electrode sheet 411 in the winding portion 41. It should be noted that the second positive electrode sheet 411 is wound around once, and the number of stacked layers along the first direction X is two.

[0135] 20%≤n / (m+n)≤80%, then optionally, n / (m+n) can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc.

[0136] After systematic analysis and a large number of experiments, the inventors found that setting 20%≤n / (m+n)≤80% is beneficial to fully utilizing the space inside the shell 31 of the battery cell 30 and improving the energy density of the battery cell 30 when the electrode assembly 40 is applied to the battery cell 30.

[0137] It should be noted that different battery cells 30 have different sizes of their outer shells 31, the thickness of the positive electrode plates 40a or the negative electrode plates 40b, and the sizes of the electrode assemblies 40. Even if n / (m+n) is the same, the specific benefits of different electrode assemblies 40 in improving energy density are not the same.

[0138] In some embodiments, 33%≤n / (m+n)≤55%.

[0139] Optionally, n / (m+n) can be 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54% or 55%, etc.

[0140] After further systematic analysis and a large number of experiments, the inventors found that setting 33%≤n / (m+n)≤55% is beneficial to further fully utilize the space inside the outer shell 31 of the battery cell 30 when the electrode assembly 40 is applied to the battery cell 30, thereby further improving the energy density of the battery cell 30.

[0141] In some embodiments, Figure 5As shown, the dimension of the electrode assembly 40 along the first direction X is smaller than the dimension along the second direction Y, and the dimension a of the second plane 41 b along the first direction X satisfies: a≥5 mm.

[0142] Since the first positive electrode sheet 421 of the stacking portion 42 of the electrode assembly 40 is stacked along the first direction X, the size of the electrode assembly 40 along the first direction X is set to be smaller than the size along the second direction Y, that is, the stacking portion 42 is set to be "flat" along the stacking direction. Since the winding portion 41 is wound around the outer peripheral side of the stacking portion 42, the winding process of the winding portion 41 is facilitated to proceed smoothly.

[0143] Optionally, a can be 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, etc.

[0144] After systematic analysis and long-term practice, the inventors found that setting a≥5 mm can help reduce the difficulty of processing the electrode assembly 40 while improving the energy density of the battery cell 30 .

[0145] In some embodiments, Figure 6 and Figure 7 As shown, the electrode assembly 40 includes a positive electrode sheet 40a and a negative electrode sheet 40b, the positive electrode sheet 40a includes a first positive electrode sheet 421 and a second positive electrode sheet 411, the negative electrode sheet 40b includes a second positive electrode sheet 411 and a second negative electrode sheet 412, along the first direction X, the positive electrode sheets 40a and the negative electrode sheets 40b are alternately arranged in layers, and the outermost circle of the winding portion 41 is the second negative electrode sheet 412.

[0146] In other words, the outermost portions of the lamination portion 42 on both sides along the first direction X are the first positive electrode sheets 421, and the innermost and outermost circles of the winding portion 41 are both the second negative electrode sheets 412. The electrode assembly 40 formed in this way is arranged along the first direction X as a whole, and the positive electrode sheets 40a and the negative electrode sheets 40b are arranged alternately in layers. Therefore, whether it is the winding portion 41 or the lamination portion 42 of the electrode assembly 40, there is only one layer of negative electrode sheet 40b between two adjacent layers of positive electrode sheets 40a, and there is only one layer of positive electrode sheet 40a between two adjacent layers of negative electrode sheets 40b.

[0147] With such arrangement, for the lithium-ion battery cell 30 , during the operation of the electrode assembly 40 , the lithium ions released from the positive electrode sheet 40 a are always received by the negative electrode sheet 40 b , which is beneficial to reducing the risk of lithium deposition in the electrode assembly 40 .

[0148] In some embodiments, Figure 6As shown, the first negative electrode sheet 422 is wound around the first positive electrode sheet 421, and the first negative electrode sheet 422 includes a first laminate sub-segment 4221 and a first bent sub-segment 4222. The first laminate sub-segment 4221 and the first positive electrode sheet 421 are stacked along a first direction X, and the first bent sub-segment 4222 connects one end of the two first laminate sub-segments 4221 along a second direction Y.

[0149] Since the first positive electrode sheet 421 is stacked along the first direction X, and the first positive electrode sheet 421 and the first negative electrode sheet 422 are alternately arranged in layers along the first direction X, during the preparation process of the stacking part 42, the first negative electrode sheet 422 can be first wound, and then the first positive electrode sheet 421 can be inserted between two adjacent first negative electrode sheets 422.

[0150] Since the first negative electrode sheet 422 is wound relative to the first positive electrode sheet 421, the first negative electrode sheet 422 naturally forms a first stacked sub-segment 4221 and a first bent sub-segment 4222 during the winding process. Moreover, since the first negative electrode sheet 422 is wound relative to the first positive electrode sheet 421, the first bent sub-segment 4222 has a larger radius of curvature. During the winding process of the first negative electrode sheet 422, the risk of the active material layer of the first negative electrode sheet 422 falling off is reduced, thereby helping to improve the reliability performance of the electrode assembly 40.

[0151] In some embodiments, Figure 7 As shown, the first negative electrode plate 422 includes a second bent sub-segment 422b and a second laminated sub-segment 422a. The second laminated sub-segments 422a and the first positive electrode plate 421 are alternately arranged in layers. The second bent sub-segment 422b connects the same end of two adjacent layers of the second laminated sub-segments 422a along the second direction Y, so that the first negative electrode plate 422 is reciprocatingly bent.

[0152] In this way, the first negative electrode plate 422 is continuous as a whole and can be folded back and forth, so that the stacking portion 42 is arranged more densely, and there is a larger gap between the stacking portion 42 and the winding portion 41 on both sides along the second direction Y. In the process of injecting electrolyte into the battery cell 30, the electrolyte can be injected using the gap, which is beneficial to improving the efficiency of electrolyte injection into the battery cell 30.

[0153] In a second aspect, the battery 10 provided in the embodiment of the present application includes the battery cell 30 provided in any of the above embodiments.

[0154] The battery 10 provided in the embodiment of the present application has the same technical effect as the battery cell 30 provided in any of the above embodiments, and thus will not be described in detail here.

[0155] In some embodiments, Fig.10As shown, the housing 31 is in a quadrangular prism shape, and the battery 10 further includes a first battery cell 50 , which is cylindrical. Any first battery cell 50 is disposed adjacent to the battery cell 30 .

[0156] The housing 31 is in a quadrangular prism shape, and the corresponding battery cell 30 may be a square battery cell 30 , and its cross section along the direction parallel to the first direction X and the second direction Y may be a square or a rectangle.

[0157] The first battery cell 50 is cylindrical, and the first battery cell 50 is arranged adjacent to the battery cell 30. There is a large gap between the surface of the first battery cell 50 and the surface of the adjacent battery cell 30. The gap can be used to dissipate the heat of the battery cell 30, which is beneficial to improving the heat dissipation efficiency of the battery cell 30 and reducing the risk of thermal runaway of the battery cell 30.

[0158] Therefore, the battery 10 includes a first battery cell 50 and a battery cell 30 , and the first battery cell 50 is arranged adjacent to the battery cell 30 . The gap formed between the two can be used to dissipate heat from the battery cell 30 , which is beneficial to reducing the risk of thermal runaway of the battery 10 .

[0159] In some embodiments, Fig.10 and Fig.11 As shown, the size of the shell 31 along the first direction X is equal to the size along the second direction Y, the diameter of the first battery cell 50 is less than or equal to the size of the shell 31 along the first direction X, and both sides of the first battery cell 50 along the first direction X and along the second direction Y are adjacent to the battery cell 30.

[0160] The size of the shell 31 along the first direction X is equal to the size along the second direction Y, and the cross-section of the battery cell 30 parallel to the first direction X and the second direction Y is square. Since the diameter of the first battery cell 50 is less than or equal to the size of the shell 31 along the first direction X, there are gaps between the first cell and two adjacent battery cells 30 along the first direction X and between two adjacent battery cells 30 along the second direction Y. On the premise of facilitating the improvement of the arrangement density of the battery cells 30, the gaps between the first battery cell 50 and the adjacent battery cells 30 can also be used to dissipate the heat of the battery cells 30, which is beneficial to improving the heat dissipation efficiency of the battery 10.

[0161] It is understandable that the first battery cell 50 may be disposed between any two connected battery cells 30 along the first direction X and the second direction Y, or the first battery cell 50 may be disposed only between two partially adjacent battery cells 30 along the first direction X or the second direction Y.

[0162] By setting the size of the housing 31 along the first direction X to be equal to the size of the second direction Y, and setting the first battery cell 50 adjacent to the battery cell 30 on both sides along the first direction X and the second direction Y, it is beneficial to improve the heat dissipation efficiency of the battery 10 and reduce the risk of thermal runaway of the battery 10 while improving the energy density of the battery 10.

[0163] In some embodiments, Fig.12 As shown, the battery 10 further includes a second battery cell 60, which is in the shape of a quadrangular prism, and the size of the second battery cell 60 along the second direction Y is greater than the size along the first direction X, and a plurality of second battery cells 60 are arranged at intervals at least along the first direction X. The battery cell 30 is in the shape of a quadrangular prism, and at least one side of the second battery cell 60 along the first direction X is provided with n battery cells 30 arranged at intervals along the second direction Y, wherein n ≥ 2, and n is a positive integer.

[0164] The second battery cell 60 is in the shape of a quadrangular prism. Optionally, the second electrode assembly of the second battery cell 60 may be the electrode assembly 40 provided in any of the above embodiments of the present application, or the second electrode assembly of the second battery cell 60 may be different from the electrode assembly 40 provided in any of the above embodiments of the present application.

[0165] The plurality of second battery cells 60 are arranged at intervals only along the first direction X, or the plurality of second battery cells 60 are arranged along the first direction X and the second direction Y.

[0166] The size of the second battery cell 60 along the second direction Y is greater than the size of the first direction X, and at least one side of the second battery cell 60 along the first direction X is provided with n battery cells 30, and the n battery cells 30 are arranged at intervals along the second direction Y. If n≥2, then optionally, n can be 2 or 3, etc. Then the size of the second battery cell 60 along the second direction Y is greater than the size of the n battery cells 30 along the second direction Y, which is beneficial to improve the overall energy density of the battery 10.

[0167] Optionally, n battery cells 30 arranged at intervals along the second direction Y may be arranged on any side of the second battery cell 60 along the first direction X, or a plurality of battery cells 30 arranged along the second direction Y may be provided on both sides of the second battery cell 60 along the first direction X, and the number of battery cells 30 arranged along the second direction Y on different sides of the second battery cell 60 along the first direction X and on any side of different battery cells 30 along the first direction X may be the same or different.

[0168] Since the n battery cells 30 are arranged at intervals, the gaps between the battery cells 30 can be used to dissipate heat for the second battery cell 60 .

[0169] Therefore, the battery 10 provided in the embodiment of the present application is beneficial to improving the heat dissipation efficiency of the battery 10 and reducing the risk of thermal runaway of the battery 10 while improving the energy density of the battery 10 .

[0170] In a third aspect, the electrical device provided in the embodiment of the present application includes the battery 10 provided in any of the above embodiments, and the battery 10 is used to provide electrical energy.

[0171] The electric device provided in the embodiment of the present application has the same technical effect as the battery 10 provided in any of the above embodiments, and thus will not be described in detail here.

[0172] In some embodiments, Figures 4 to 9 As shown, the battery cell 30 includes a housing 31 and an electrode assembly 40, and the electrode assembly 40 includes a winding portion 41 and a laminate portion 42, and the winding portion 41 is wound around the outer peripheral side of the laminate portion 42. The outer peripheral surface of the winding portion 41 includes an arcuate surface 41c, two first planes 41a opposite to each other along a first direction X, and two second planes 41b opposite to each other along a second direction Y. The arcuate surface 41c connects the adjacent first planes 41a and second planes 41b, and the first direction X, the second direction Y, and the winding center line of the winding portion 41 are perpendicular to each other. The curvature radius r of the arcuate surface 41c satisfies: 2mm≤r≤8mm. The lamination portion 42 includes a first positive electrode sheet 421 and a first negative electrode sheet 422, and the winding portion 41 includes a second positive electrode sheet 411 and a second negative electrode sheet 412. The second positive electrode sheet 411 and the second negative electrode sheet 412 are wound alternately in layers, and the first positive electrode sheet 421 and the first negative electrode sheet 422 are alternately arranged in layers along the first direction X, and any two layers of the first positive electrode sheets 421 are disconnected from each other. The number of layers of the first positive electrode sheet 421 along the first direction X is n, and the number of layers of the second positive electrode sheet 411 along the first direction X is m, and 20%≤n / (m+n)≤80%. The size of the electrode assembly 40 along the first direction X is smaller than the size along the second direction Y, and the size a of the second plane 41b along the first direction X satisfies: a≥5mm. The electrode assembly 40 includes a positive electrode sheet 40a and a negative electrode sheet 40b. The positive electrode sheet 40a includes a first positive electrode sheet 421 and a second positive electrode sheet 411. The negative electrode sheet 40b includes a second positive electrode sheet 411 and a second negative electrode sheet 412. Along the first direction X, the positive electrode sheets 40a and the negative electrode sheets 40b are alternately arranged in layers, and the outermost circle of the winding portion 41 is the second negative electrode sheet 412.

[0173] The battery cell 30 provided in the embodiment of the present application is provided with an electrode assembly 40 including a winding portion 41 and a lamination portion 42, and the winding portion 41 is wound on the outer peripheral side of the lamination portion 42, so that the outer peripheral surface of the winding portion 41 of the electrode assembly 40 includes a first plane 41a opposite to each other along the first direction X and a second plane 41b opposite to each other along the second direction Y, and an arc surface 41c connecting the adjacent first planes 41a and second planes 41b, so that it is beneficial to reduce the gap between the electrode assembly 40 and the housing 31, increase the space inside the battery cell 30 occupied by the electrode assembly 40, and further improve the group margin and energy density of the battery cell 30. In addition, there is a gap between the winding portion 41 and the lamination portion 42 of the electrode assembly 40. In the process of injecting electrolyte into the battery cell 30, the gap between the winding portion 41 and the lamination portion 42 is beneficial to improve the smoothness of electrolyte injection.

[0174] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises a housing and an electrode assembly, wherein the electrode assembly is accommodated in the housing, and the electrode assembly comprises a winding portion and a lamination portion, wherein the winding portion is wound around the outer circumference of the lamination portion; The outer peripheral surface of the winding portion includes an arcuate surface, two first planes opposite to each other along a first direction, and two second planes opposite to each other along a second direction. The arcuate surface connects the adjacent first planes and second planes. The first direction, the second direction and the winding center line of the winding portion are perpendicular to each other.

2. The battery cell according to claim 1, characterized in that: The curvature radius r of the arc-shaped surface satisfies: 2mm≤r≤8mm.

3. The battery cell according to claim 2, characterized in that: 3mm≤r≤5mm.

4. The battery cell according to claim 1, characterized in that: The stacking portion includes a first positive electrode sheet and a first negative electrode sheet, the winding portion includes a second positive electrode sheet and a second negative electrode sheet, the second positive electrode sheet and the second negative electrode sheet are alternately wound in layers, the first positive electrode sheet and the first negative electrode sheet are alternately arranged in layers along the first direction, and any two layers of the first positive electrode sheets are disconnected from each other.

5. The battery cell according to claim 4, characterized in that: The number of layers of the first positive electrode sheets along the first direction is n, the number of layers of the second positive electrode sheets along the first direction is m, and 20%≤n / (m+n)≤80%.

6. The battery cell according to claim 5, characterized in that: 33%≤n / (m+n)≤55%.

7. The battery cell according to any one of claims 4 to 6, characterized in that: The size of the electrode assembly along the first direction is smaller than the size along the second direction, and the size a of the second plane along the first direction satisfies: a≥5 mm.

8. The battery cell according to any one of claims 4 to 6, characterized in that: The electrode assembly includes positive electrode sheets and negative electrode sheets, the positive electrode sheets include the first positive electrode sheets and the second positive electrode sheets, the negative electrode sheets include the second positive electrode sheets and the second negative electrode sheets, along the first direction, the positive electrode sheets and the negative electrode sheets are alternately arranged in layers, and the outermost circle of the winding portion is the second negative electrode sheet.

9. The battery cell according to claim 8, characterized in that: The first negative electrode sheet is wound around the first positive electrode sheet, and the first negative electrode sheet includes a first laminate sub-segment and a first bent sub-segment. The first laminate sub-segment and the first positive electrode sheet are stacked along the first direction, and the first bent sub-segment connects the same end of two layers of the first laminate sub-segments along the second direction.

10. The battery cell according to claim 8, characterized in that: The first negative electrode sheet includes a second bent sub-segment and a second laminated sub-segment, the second laminated sub-segments and the first positive electrode sheet are alternately arranged in layers, and the second bent sub-segment connects the same end of two adjacent layers of the second laminated sub-segments along the second direction so that the first negative electrode sheet is reciprocatingly bent.

11. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 10.

12. The battery according to claim 11, characterized in that The housing is in a quadrangular prism shape, and the battery further includes a first battery cell, which is in a cylindrical shape, and any of the first battery cells is disposed adjacent to the battery cell.

13. The battery according to claim 12, characterized in that The size of the shell along the first direction is equal to the size along the second direction, the diameter of the first battery cell is smaller than or equal to the size of the shell along the first direction, and both sides of the first battery cell along the first direction and the second direction are adjacent to the battery cell.

14. The battery according to claim 11, characterized in that The battery also includes a second battery cell, which is in the shape of a quadrangular prism, the size of the second battery cell along the second direction is larger than the size along the first direction, and a plurality of the second battery cells are arranged at intervals at least along the first direction; the battery cell is in the shape of a quadrangular prism, and at least one side of the second battery cell along the first direction is provided with n battery cells arranged at intervals along the second direction, wherein n≥2, and n is a positive integer.

15. An electrical device, characterized in that: The invention comprises a battery as claimed in any one of claims 11 to 14, wherein the battery is used to provide electrical energy.

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