Battery cell, electrode assembly, winding needle, battery, and electrical device

Abstract

Provided are a battery cell (100), an electrode assembly (20), a winding needle (2), a battery (1000), and an electrical device. The battery cell (100) comprises a housing (10) and the electrode assembly (20). The electrode assembly (20) is disposed within the housing (10), and the electrode assembly (20) comprises a wound electrode sheet (21). The electrode sheet (21) comprises a first main body section (201) and a second main body section (202) connected along the winding direction. The second main body section (202) is arranged around the first main body section (201). The first main body section (201) is provided with a protrusion-recess structure (2011). The battery cell (100) has improved reliability.

Description

Battery cell, electrode assembly, winding needle, battery and electric device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202421823631.9, filed on July 30, 2024, entitled “Battery cell, electrode assembly, winding needle, battery and electric device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, in particular to a battery cell, an electrode assembly, a winding needle, a battery and an electric device. BACKGROUND

[0004] Battery cells are widely used in electronic devices, such as mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools, etc. Battery cells can include cadmium-nickel battery cells, hydrogen-nickel battery cells, ion battery cells and secondary alkaline zinc-manganese battery cells, etc.

[0005] In the development of battery technology, how to improve the reliability of battery cells is a research direction in battery technology.

[0006] Practical new type content

[0007] In view of the above problems, the present application provides a battery cell, an electrode assembly, a winding needle, a battery and an electric device, which is beneficial to improve the reliability of the battery cell.

[0008] In a first aspect, the present application provides a battery cell, comprising: a shell; an electrode assembly arranged in the shell, the electrode assembly comprising a winding arranged electrode tab; wherein the electrode tab comprises a first body segment and a second body segment connected along the winding direction, the second body segment is arranged around the first body segment, and the first body segment is provided with a concave-convex structure.

[0009] In some embodiments of the first aspect, by providing the first body segment with a concave-convex structure, the support effect of the first body segment as a whole is provided, the compression resistance of the first body segment is increased, and the part of the first body segment provided with the concave-convex structure can be deformed to reduce or even absorb the expansion force transmitted to other positions of the first body segment, so as to prevent the first body segment as a whole from collapsing towards the center hole of the electrode assembly, thereby reducing the safety problems caused by the collision of the electrode tab during the charging and discharging process of the battery cell, and improving the reliability and service life of the battery cell.

[0010] In some embodiments, the concave-convex structure comprises a convex part protruding from one side of the first body segment along the thickness direction of the pole piece, and a concave part recessed from the other side of the first body segment along the thickness direction, and the position of the convex part corresponds to the position of the concave part. By setting in this way, the resistance effect of the part of the first body segment provided with the concave-convex structure to the expansion force of the pole piece can be further improved, so that the collapse of the first body segment can be further prevented.

[0011] In some embodiments, the pole piece is wound N turns from inside to outside along the winding direction, and the first body segment starts from the 1st turn and extends to the Mth turn, where 2≤M≤N. The first body segment provided with the concave-convex structure is wound at least two turns from inside to outside, which is conducive to better improving the resistance effect of the first body segment to the expansion force of the pole piece, thereby better preventing the collapse of the first body segment.

[0012] In some embodiments, along the winding direction, the concave-convex structures provided on the first body segments of adjacent two turns are engaged with each other. By setting in this way, the occupied space of the first body segment provided with the concave-convex structure can be reduced, thereby facilitating the reduction of the influence of the concave-convex structure on the energy density of the battery cell.

[0013] In some embodiments, the thickness dimension d of the first body segment and the maximum height dimension h of the concave-convex structure along the thickness direction of the pole piece satisfy the relationship: 1 / 600≤d / h≤3 / 100. By setting the ratio of the thickness dimension d of the first body segment to the maximum height dimension h of the concave-convex structure within the above range, the structural strength of the first body segment can be improved while ensuring that the first body segment provided with the concave-convex structure has sufficient bending resistance.

[0014] In some embodiments, the maximum height dimension h satisfies the relationship: 0.5mm≤h≤3mm. By setting the maximum height dimension h of the concave-convex structure within the above range, it is conducive to ensuring that the first body segment provided with the concave-convex structure has sufficient compression resistance.

[0015] In some embodiments, the first body segment comprises a current collector, and the thickness dimension of the current collector is greater than or equal to 5μm and less than or equal to 15μm. By setting the thickness dimension of the current collector within the above range, the effectiveness of the current collector provided with the concave-convex structure can be ensured.

[0016] In some embodiments, the first body segment further comprises a conductive coating coated on the current collector, or the first body segment further comprises an active material layer coated on the current collector, and the thickness dimension of the active material layer is greater than or equal to 15μm and less than or equal to 40μm. By the above setting, the effectiveness of the current collector coated with the conductive coating or the active material layer provided with the concave-convex structure can be ensured.

[0017] In some embodiments, the concave-convex structure is a strip structure, and the concave-convex structure is arranged along at least one of an axial direction of the electrode assembly and a winding direction. In this way, the concave-convex structure is formed on the first body segment.

[0018] In some embodiments, a projection of the concave-convex structure in the winding direction is any one of a polygonal structure and a sector structure; or, a projection of the concave-convex structure in the axial direction of the electrode assembly is any one of a polygonal structure and a sector structure. In this way, the diversity of the concave-convex structure is improved, thereby improving the diversity of the battery cell.

[0019] In some embodiments, the number of the concave-convex structures is multiple. Such a design facilitates improving the compression resistance of the first body segment provided with the concave-convex structure, and better prevents the first body segment from being depressed.

[0020] In some embodiments, the multiple concave-convex structures are spaced apart along the winding direction, and / or the multiple concave-convex structures are spaced apart along the axial direction of the electrode assembly. In this way, the flexibility of use is improved.

[0021] In some embodiments, in the axial direction of the electrode assembly, the length dimension of the concave-convex structure is the same as the length dimension of the first body segment. In this way, the distribution area of the concave-convex structure on the first body segment is increased, so that the first body segment has better compression resistance.

[0022] In a second aspect, the present application provides an electrode assembly, comprising a jelly-roll arranged electrode tab, the jelly-roll arranged electrode tab comprising a first body segment and a second body segment connected along a winding direction, the second body segment being arranged around the first body segment, and the first body segment being provided with a concave-convex structure.

[0023] In some embodiments of the second aspect, the first body segment is provided with the concave-convex structure to provide support to the first body segment, increase the compression resistance of the first body segment, and the part of the first body segment provided with the concave-convex structure can be deformed to reduce or even absorb the expansion force transmitted to other positions of the first body segment, prevent the whole first body segment from collapsing towards the center hole, and improve the reliability and service life of the electrode assembly.

[0024] In a third aspect, the present application provides a winding needle for forming an electrode assembly, the electrode assembly comprising a jelly-roll arranged electrode tab, the jelly-roll arranged electrode tab being provided with a concave-convex structure, the winding needle comprising: a winding body configured to wind the electrode tab; and a protruding portion protruding from an outer circumferential surface of the winding body, the protruding portion being configured to push the electrode tab to form the concave-convex structure.

[0025] In some embodiments of the third aspect, the winding needle is provided with a protruding portion protruding from the outer circumferential surface of the winding body, and the electrode assembly wound by the winding needle is pushed by the protruding portion to form a concave-convex structure near the central hole position, thereby preventing the electrode assembly from collapsing near the central hole position.

[0026] In a fourth aspect, the application provides a battery comprising the battery cell according to any one of the embodiments of the first aspect.

[0027] In a fifth aspect, the application provides a power consuming device comprising the battery according to any one of the embodiments of the fourth aspect, wherein the battery is configured to provide electric energy.

[0028] The above description is only a summary of the technical solutions of the application. In order to enable one of ordinary skill in the art to better understand the technical means of the application and implement it according to the contents of the description, and in order to enable the above and other purposes, characteristics and advantages of the application to be more apparent and easy to understand, the following detailed description of the specific embodiments of the application is provided. BRIEF DESCRIPTION OF DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a better understanding of the preferred embodiments, and are not to be considered as limitations on the present application. Moreover, in the drawings, like reference numerals refer to similar components throughout the several views. In the drawings:

[0030] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the application;

[0031] FIG. 2 is an exploded structural schematic diagram of a battery according to some embodiments of the application;

[0032] FIG. 3 is a structural schematic diagram of a battery module according to some embodiments of the application;

[0033] FIG. 4 is an exploded structural schematic diagram of a battery cell according to some embodiments of the application;

[0034] FIG. 5 is a partial sectional view of an electrode assembly in a battery cell according to some embodiments of the application;

[0035] FIG. 6 is a partial structural schematic diagram of a tab in a battery cell according to some embodiments of the application;

[0036] FIG. 7 is a sectional structural schematic diagram of FIG. 6 along A-A;

[0037] FIG. 8 is a partial sectional view of a tab in a battery cell according to some embodiments of the application;

[0038] FIG. 9 is a partial sectional view of a tab in a battery cell according to some other embodiments of the application;

[0039] Fig. 10 is a partial sectional view of a tab in a battery cell according to some embodiments of the present application;

[0040] Fig. 11 is a partial structural schematic view of a tab in a battery cell according to some embodiments of the present application;

[0041] Fig. 12 is a sectional structural schematic view of Fig. 11 along B-B;

[0042] Fig. 13 is a partial sectional view of a tab in a battery cell according to some embodiments of the present application;

[0043] Fig. 14 is a structural schematic view of a winding needle according to some embodiments of the present application;

[0044] Fig. 15 is a structural schematic view of a winding needle according to some embodiments of the present application;

[0045] Fig. 16 is a structural schematic view of a winding needle according to some embodiments of the present application.

[0046] The reference signs in the detailed description are as follows: 1-vehicle; 1000-battery; 2000-controller; 3000-motor; 100a-battery module; 100-battery cell; 200-box body; 210-first box body part; 220-second box body part; 200a-accommodation cavity; 10-housing; 101-end cover; 102-housing body; 10a-electrode terminal; 20-electrode assembly; 21-tab; 211-positive electrode tab; 212-negative electrode tab; 201-first body segment; 2011-convex-concave structure; 2011a-convex part; 2011b-concave part; 202-second body segment; 22-separator; 2-winding needle; 2001-winding body; 2002-protruding part; X-winding direction; Y-thickness direction; Z-axis direction; L-length direction; W-width direction. DETAILED DESCRIPTION

[0047] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0048] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should be understood as the usual meanings understood by the skilled in the art to which the embodiments of the present application belong.

[0049] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0050] In addition, the technical terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0051] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0052] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0053] At present, from the development of market situation, the application of battery is more and more widely. The battery is not only applied to the energy storage power supply system of hydroelectric, thermal power, wind power and solar power station, but also widely applied to electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of battery, the demand of its market is also increasing.

[0054] The development of battery technology needs to consider various design factors, such as battery life, energy density, discharge capacity, charge-discharge rate, and other performance parameters. In addition, the reliability of the battery also needs to be considered.

[0055] The battery referred to 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. For example, the battery referred to in the present application can include a battery module or a battery pack, etc.

[0056] The battery cell can be a secondary battery cell, which refers to a battery cell that can be activated by charging after discharging the battery cell.

[0057] In the related art, in the cycle process of charging and discharging, the anode and cathode material particles in the battery cell will expand. Since the center of the battery cell formed by winding has a center hole, when the pole piece expands during the cycle process, there is no support for the inner ring pole piece towards the center hole position, which causes the collapse problem at the center hole position, causing damage to the electrode assembly, thereby reducing the reliability of the battery cell.

[0058] Based on the above technical problems, the embodiments of the present application provide a battery cell, which includes a shell and an electrode assembly. The electrode assembly is arranged in the shell, and the electrode assembly includes a pole piece arranged by winding. Wherein, the pole piece includes a first body segment and a second body segment connected along the winding direction, the second body segment is arranged around the first body segment, and the first body segment is provided with a concave-convex structure.

[0059] The first body segment is arranged close to the center hole of the electrode assembly. By providing the concave-convex structure on the first body segment, the support effect of the first body segment as a whole is provided, the compression resistance of the first body segment is increased, and the part of the first body segment provided with the concave-convex structure can be deformed to reduce or even absorb the expansion force transmitted to other positions of the first body segment, preventing the first body segment as a whole from collapsing towards the center hole of the electrode assembly, thereby reducing the safety problem caused by the collision of the pole piece during the charging and discharging process of the battery cell, and improving the reliability and service life of the battery cell.

[0060] The technical solutions described in the embodiments of the present application are applicable to various devices using batteries, such as mobile phones, portable devices, notebook computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.

[0061] It should be understood that the technical solutions described in the embodiments of the present application are not only limited to the above described devices, but also applicable to all devices using batteries, but for the sake of brevity, the following embodiments are described by taking vehicles as examples.

[0062] For example, as shown in FIG. 1, which is a structural schematic diagram of a vehicle 1 according to an embodiment of the present application, the vehicle 1 can be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or a range extended vehicle. The vehicle 1 can be provided with a motor 3000, a controller 2000, and a battery 1000, and the controller 2000 is configured to control the battery 1000 to supply power to the motor 3000. For example, the battery 1000 can be arranged at the bottom, the front, or the rear of the vehicle 1. The battery 1000 can be used to supply power to the vehicle 1, for example, the battery 1000 can be used as an operating power source of the vehicle 1, and can be used for the circuit system of the vehicle 1, for example, for the power demand of the vehicle 1 during starting, navigation, and operation. In another embodiment of the present application, the battery 1000 can not only be used as an operating power source of the vehicle 1, but also be used as a driving power source of the vehicle 1, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1.

[0063] As shown in FIG. 2 and FIG. 3, in order to meet different power demands, the battery 1000 can include a plurality of battery cells 100, and the plurality of battery cells 100 can be connected in series, in parallel, or in a mixed connection. The mixed connection refers to a mixture of series connection and parallel connection. The battery 1000 can also be referred to as a battery pack. Alternatively, the plurality of battery cells 100 can be connected in series, in parallel, or in a mixed connection to form a battery module 100a, and the plurality of battery modules 100a can be connected in series, in parallel, or in a mixed connection to form the battery 1000. That is, the plurality of battery cells 100 can be directly connected to form the battery 1000, or the plurality of battery cells 100 can be connected to form the battery module 100a, and the battery module 100a can be connected to form the battery 1000.

[0064] In the present application, the battery cell 100 can include a lithium ion battery cell, a sodium ion battery cell, or a magnesium ion battery cell, and the present application is not limited thereto. The battery cell 100 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, and the present application is not limited thereto.

[0065] As shown in FIG. 2, the battery 1000 according to an embodiment of the present application further includes a box body 200, and the plurality of battery cells 100 are accommodated in the box body 200, and the box body 200 can protect the battery cells 100.

[0066] The box body 200 can be a simple solid structure such as a cuboid or a cylinder or a sphere, or a complex solid structure composed of a simple solid structure such as a cuboid or a cylinder or a sphere, and the present application is not limited thereto. The material of the box body 200 can be an alloy material such as an aluminum alloy or an iron alloy, or a high polymer material such as polycarbonate or polyisocyanurate foam plastic, or a composite material such as glass fiber and epoxy resin, and the present application is not limited thereto.

[0067] The box 200 is used to accommodate the battery monomer 100, and the box 200 can be of various structures. In some embodiments, the box 200 can include a first box part 210 and a second box part 220, the first box part 210 and the second box part 220 are mutually covered, and the first box part 210 and the second box part 220 jointly define an accommodation cavity 200a used to accommodate the battery monomer 100. The first box part 210 and the second box part 220 can each be a hollow structure with one open side, and the open side of the first box part 210 is covered on the open side of the second box part 220 to form the box 200 with the accommodation cavity 200a. Of course, the first box part 210 and the second box part 220 can be of various shapes, such as a cylinder, a cuboid, etc. The first box part 210 can also be a plate-shaped structure, and the second box part 220 can be a hollow structure with one open side.

[0068] To improve the sealing performance of the first box part 210 and the second box part 220 after being connected, a sealing member such as sealing glue, a sealing ring, etc. can also be arranged between the first box part 210 and the second box part 220.

[0069] Please refer to FIGS. 4 to 13, according to the embodiments of the present application, a battery monomer 100 is provided, which includes a shell 10 and an electrode assembly 20. The electrode assembly 20 is arranged in the shell 10, and the electrode assembly 20 includes a jelly-roll-shaped electrode tab 21. The electrode tab 21 includes a first body segment 201 and a second body segment 202 connected along a winding direction X, the second body segment 202 is arranged around the first body segment 201, and the first body segment 201 is provided with a concave-convex structure 2011.

[0070] The shell 10 is a component used to form an internal environment of the battery monomer 100, and the internal environment formed by the shell 10 can be used to accommodate the electrode assembly 20 and can also be used to accommodate electrolyte and other components. Optionally, the shell 10 can be made of, but is not limited to, a metal or a non-metal material, for example, the metal material can be copper, aluminum, or stainless steel, etc., and the non-metal material can be polyethylene, polypropylene, or polyvinyl chloride, etc.

[0071] The electrode assembly 20 is a component in which electrochemical reactions occur in the battery monomer 100, and the shell 10 can contain one or more electrode assemblies 20.

[0072] The electrode assembly 20 includes a jelly-roll electrode sheet 21. Specifically, the jelly-roll electrode sheet 21 can include positive electrode sheets 211 and negative electrode sheets 212 having opposite polarities. The positive electrode sheets 211 and the negative electrode sheets 212 have portions with active materials constituting a main body of the electrode assembly 20, and portions without active materials each constituting a tab. The positive electrode tab and the negative electrode tab can be located together at one end of the main body or at two ends of the main body, respectively. During charging and discharging of the battery 1000, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to the electrode terminal 10a to form a current loop. The positive electrode sheets 211 and the negative electrode sheets 212 can further be provided with a separator 22. In some embodiments, the positive electrode sheets 211 and the negative electrode sheets 212 can further be provided without the separator 22.

[0073] The electrode assembly 20 can include any one of a cylindrical electrode assembly, a rectangular electrode assembly, and an elliptical electrode assembly.

[0074] Optionally, the negative electrode sheet 212 can include a first body segment 201 and a second body segment 202 connected in the winding direction X, i.e., the negative electrode sheet 212 is arranged closer to the center hole of the electrode assembly 20 than the positive electrode sheet 211 in the jelly-roll electrode assembly 20; alternatively, the positive electrode sheet 211 can also include a first body segment 201 and a second body segment 202 connected in the winding direction X.

[0075] As shown in FIGS. 4 and 5, the positive electrode sheet 211 includes a first body segment 201 and a second body segment 202 connected in the winding direction X.

[0076] As shown in FIGS. 6 and 11, FIGS. 6 and 11 can each represent a structure of the electrode sheet 21 before being wound. In the electrode assembly 20 as shown in FIGS. 4 and 5, the electrode sheet 21 includes a first body segment 201 and a second body segment 202 connected in the winding direction X, and the electrode sheet 21 after being wound encloses a center hole. It can be understood that, in the electrode sheet 21 as shown in FIGS. 6 and 11, the electrode sheet 21 includes a first body segment 201 and a second body segment 202 connected in a length direction L. That is, the concave-convex structure 2011 can be arranged on the first body segment 201 of the electrode sheet 21 before the electrode sheet 21 is wound.

[0077] In the related art, to solve the problem of collapse of the center hole position, a tube is inserted into the center hole after the electrode sheet is wound to form the electrode assembly. However, the insertion process of the tube is difficult to implement and is prone to cause friction between the tube and the electrode sheet and displacement of the electrode sheet. In addition, the additional tube increases the overall weight of the battery monomer, reduces the energy density, and occupies the space of the winding through hole, resulting in insufficient space for the electrolyte.

[0078] Therefore, by the above setting, that is, dividing the first body section 201 and the second body section 202 on the un-wound pole piece 21 in advance, and then processing the concave-convex structure 2011 on the first body section 201, it is convenient for processing and manufacturing, and can also prevent the risk of displacement of the pole piece 21, and will not additionally increase the structure to affect the overall weight of the battery monomer 100, so as not to affect the energy density of the battery monomer 100, and in addition, after the concave-convex structure 2011 is provided, there is also enough space for the electrolyte to remain at the center hole of the electrode assembly 20, which is beneficial to improve the reliability of the battery monomer 100. Specifically, the first body section 201 and the second body section 202 can be divided on the pole piece 21 according to user needs.

[0079] Among them, the concave-convex structure 2011 can be understood as that the first body section 201 has at least one of the convex part 2011a and the concave part 2011b on at least one side along the thickness direction Y of the pole piece 21, that is, the two side surfaces of the first body section 201 along the thickness direction Y are concave-convex.

[0080] The thickness direction Y of the pole piece 21 can also be understood as the radial direction of the electrode assembly 20 as shown in FIGS. 4 and 5.

[0081] Optionally, the concave-convex structure 2011 and the first body section 201 are an integral molding structure, the concave-convex structure 2011 can be made by stretching molding or extrusion molding process of the first body section 201, without adding new components, which will not affect the weight and energy density of the battery monomer 100, and the pole piece 21 with the concave-convex structure 2011 can be obtained before winding, without setting the concave-convex structure 2011 after the electrode assembly 20 is wound and formed, so as to avoid displacement of the pole piece 21, and the concave-convex structure 2011 will not occupy the center hole, which is beneficial to improve the reliability and service life of the battery monomer 100.

[0082] Specifically, the concave-convex structure 2011 can be stamped from the first body section 201 along its own thickness direction Y, so that the structural strength of the first body section 201 at the position where the concave-convex structure 2011 is provided is greater than that of other positions of the first body section 201, which is beneficial to improve the compression resistance of the first body section 201 to delay or even avoid its collapse towards the center hole position. And, the concave-convex structure 2011 position of the first body section 201 has a deformation space, and the part of the first body section 201 located at the concave-convex structure 2011 can be deformed to reduce or even absorb the expansion force transmitted to other positions of the first body section 201, further preventing the whole first body section 201 from collapsing towards the center hole.

[0083] The battery monomer 100 provided by one embodiment of the present application is provided with the concave-convex structure 2011 on the first body segment 201 to provide support to the first body segment 201 as a whole, increase the compression resistance of the first body segment 201, and the part of the first body segment 201 located in the concave-convex structure 2011 can be deformed to reduce or even absorb the expansion force transmitted to other positions of the first body segment 201, prevent the first body segment 201 as a whole from collapsing towards the center hole, and reduce the safety problems caused by the collision of the pole piece 21 during the charging and discharging of the battery monomer 100, thereby improving the reliability and service life of the battery monomer 100.

[0084] As shown in FIG. 4, the shell 10 can include an end cover 101 and a shell body 102 having an opening, and the end cover 101 is connected with the shell body 102 and closes the opening. The end cover 101 and the shell body 102 can be independent components, and the opening can be provided on the shell body 102, and the internal environment of the battery monomer 100 is formed by covering the opening with the end cover 101.

[0085] The shell body 102 can be in various shapes and sizes, such as a cuboid, a cylinder, a hexagonal prism, etc. Specifically, the shape of the shell body 102 can be determined according to the specific shape and size of the electrode assembly 2020. The material of the shell body 102 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not have special restrictions thereon.

[0086] In some embodiments, the shell body 102 can be a rectangular shell body 102, and the electrode assembly 20 can correspondingly be a rectangular electrode assembly 20. The shell body 102 includes a bottom wall and four side walls surrounding the edges of the bottom wall. The four side walls surround an opening at one end away from the bottom wall, and the end cover 101 is connected with the four side walls to close the opening.

[0087] In some embodiments, the shell body 102 can be a circular shell body 102, and the electrode assembly 20 can correspondingly be a cylindrical electrode assembly 20. The shell body 102 includes a bottom wall and a peripheral wall surrounding the edges of the bottom wall. The peripheral wall surrounds an opening at one end away from the bottom wall, and the end cover 101 is connected with the peripheral wall to close the opening.

[0088] The end cover 101 refers to a component covering the opening of the shell body 102 to isolate the internal environment of the battery monomer 100 from the external environment. Without limitation, the shape of the end cover 101 can be adapted to the shape of the shell body 102 to fit the shell body 102. The material of the end cover 101 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not have special restrictions thereon.

[0089] Please refer to FIG. 8 and FIG. 9, in some embodiments, the concave-convex structure 2011 includes a convex part 2011a and a concave part 2011b, the convex part 2011a is convexly arranged on one side of the first body segment 201 along the thickness direction Y of the pole piece 21, and the concave part 2011b is concavely arranged on the other side of the first body segment 201 along the thickness direction Y, and the position of the convex part 2011a corresponds to the position of the concave part 2011b.

[0090] The position of the convex part 2011a corresponds to the position of the concave part 2011b, which can be understood as that the orthographic projection of the convex part 2011a on the thickness direction Y is arranged in an overlapping manner with the orthographic projection of the concave part 2011b on the thickness direction Y.

[0091] As shown in FIG. 8, one convex part 2011a and one concave part 2011b opposite to the convex part 2011a can be regarded as one concave-convex structure 2011, that is, the concave-convex structure 2011 includes one convex part 2011a and one concave part 2011b; or, as shown in FIG. 9, two convex parts 2011a and two concave parts 2011b opposite to the two convex parts 2011a respectively can also be regarded as one concave-convex structure 2011, that is, the concave-convex structure 2011 includes two convex parts 2011a and two concave parts 2011b; or, a plurality of convex parts 2011a and a plurality of concave parts 2011b opposite to the plurality of convex parts 2011a respectively can also be regarded as one concave-convex structure 2011. In the embodiments of the present application, one concave-convex structure 2011 includes one convex part 2011a and one concave part 2011b.

[0092] The battery monomer 100 provided by one embodiment of the present application is arranged in this way, which can further improve the resistance effect of the part of the first body segment 201 provided with the concave-convex structure 2011 to the expansion force of the pole piece 21, thereby further preventing the first body segment 201 from collapsing and improving the reliability of the battery monomer 100.

[0093] Optionally, the convex part 2011a is convexly arranged on one side of the first body segment 201 along the thickness direction Y towards the second body segment 202, and the concave part 2011b is concavely arranged on one side of the first body segment 201 along the thickness direction Y towards the second body segment 202.

[0094] Optionally, the number of the concave-convex structure 2011 can be one, two or more.

[0095] Optionally, two or more concave-convex structures 2011 can be distributed at intervals, or can be arranged continuously, and the continuous arrangement of two or more concave-convex structures 2011 means that the concave-convex structures 2011 on the first body segment 201 as a whole present a wave shape.

[0096] The concave-convex structure 2011 can be in various shapes. For example, the convex part 2011a can be a rectangular protrusion extending along a rectangular trajectory, and the concave part 2011b can be a rectangular groove extending along the rectangular trajectory; or the convex part 2011a can be a U-shaped protrusion extending along a U-shaped trajectory, and the concave part 2011b can be a U-shaped groove extending along the U-shaped trajectory; or the convex part 2011a can be a V-shaped protrusion extending along a V-shaped trajectory, and the concave part 2011b can be a V-shaped groove extending along the V-shaped trajectory.

[0097] In some embodiments, the pole piece 21 is wound N turns from inside to outside along the winding direction X, and the first body segment 201 starts from the 1st turn and extends to the Mth turn, where 2≤M≤N.

[0098] The pole piece 21 is wound N turns from inside to outside along the winding direction X, and the inner side of the electrode assembly 20 formed by winding has a central hole. The first body segment 201 starts from the 1st turn and extends to the Mth turn. It can be understood that, starting from the end of the first body segment 201 away from the second body segment 202 along the length direction L of the pole piece 21, the electrode assembly 20 formed by winding, from the central hole of the electrode assembly 20 towards the outer peripheral surface of the electrode assembly 20, the 1st turn to the Mth turn are all the first body segment 201 provided with the concave-convex structure 2011.

[0099] The value of M can be 2, that is, the electrode assembly 20 has two turns of the first body segment 201 provided with the concave-convex structure 2011. Of course, the value of M can also be set to 2.5, 3, etc.

[0100] The battery monomer 100 provided in an embodiment of the present application has the first body segment 201 provided with the concave-convex structure 2011 wound at least two turns from inside to outside, which is beneficial to better improve the resistance effect of the first body segment 201 to the expansion force of the pole piece 21, thereby better preventing the first body segment 201 from collapsing.

[0101] In other embodiments, as shown in FIG. 5, the pole piece 21 can also be provided with the first body segment 201 only at the position of the 1st turn, which can also play a role in preventing the first body segment 201 from collapsing.

[0102] In some embodiments, along the winding direction X, the concave-convex structures 2011 provided by the first body segments 201 of adjacent two turns are engaged with each other.

[0103] The engagement of the concave-convex structures 2011 with each other can be understood as that the concave-convex structure 2011 of the first body segment 201 of the inner turn and the concave-convex structure 2011 of the first body segment 201 of the outer turn are at least partially overlapped in the winding direction X, so as to reduce the radial space occupied thereby.

[0104] In this way, the first body segment 201 provided with the concave-convex structure 2011 can occupy less space, thereby reducing the influence of the concave-convex structure 2011 on the energy density of the battery cell 100.

[0105] For example, the first body segment 201 starts from the first circle and extends to the second circle, and the convex part 2011a of the first circle extends into the concave part 2011b of the second circle, i.e., the concave-convex structure 2011 of the first circle and the concave-convex structure 2011 of the second circle are engaged with each other.

[0106] For example, the thickness dimension d of the first body segment 201 and the maximum height dimension h of the concave-convex structure 2011 satisfy the relationship: 1 / 600≤d / h≤3 / 100 along the thickness direction Y of the pole piece 21.

[0107] The maximum height dimension h of the concave-convex structure 2011 refers to the distance from one end to the other end of the concave-convex structure 2011 in the thickness direction Y.

[0108] For example, the ratio d / h between the thickness dimension d and the maximum height dimension h can be, but is not limited to, 1 / 600, 1 / 500, 1 / 400, 1 / 100, 3 / 100, etc.

[0109] The thickness dimension d of the first body segment 201 at different positions can be the same or different.

[0110] It can be understood that the thickness dimension d of the first body segment 201 affects the structural performance of the first body segment 201 itself, and the maximum height dimension h of the concave-convex structure 2011 affects the structural strength of the first body segment 201 at the position of the concave-convex structure 2011. Therefore, in order to prevent the structural performance of the first body segment 201 from being affected after the concave-convex structure 2011 is provided, by setting the ratio of the thickness dimension d of the first body segment 201 to the maximum height dimension h of the concave-convex structure 2011 within the above range, the structural performance of the first body segment 201 itself can be effectively improved.

[0111] The battery cell 100 provided by one embodiment of the present application can ensure that the first body segment 201 provided with the concave-convex structure 2011 has sufficient bending resistance while improving the structural strength of the first body segment 201 by setting the ratio of the thickness dimension d of the first body segment 201 to the maximum height dimension h of the concave-convex structure 2011 within the above range.

[0112] In some embodiments, the maximum height dimension h satisfies the relationship: 0.5mm≤d / h≤3mm.

[0113] As an example, the maximum height dimension h of the concave-convex structure 2011 can be, but is not limited to, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, etc.

[0114] It can be understood that the higher the height of the concave-convex structure 2011, the better the supporting effect on the structural strength of the first body section 201, but the higher the space occupancy of the concave-convex structure 2011 itself; the smaller the height of the concave-convex structure 2011, the smaller the space occupancy, but the smaller the supporting effect on the structural strength of the first body section 201.

[0115] Therefore, by setting the maximum height dimension h of the concave-convex structure 2011 in the above range, both the reinforcing effect of the concave-convex structure 2011 can be ensured, and the influence on the energy density of the battery monomer 100 can be reduced.

[0116] Further, the maximum height dimension h satisfies the relationship: 1 mm≤d / h≤2.5 mm, which can further optimize the balance between the structural strength of the position where the concave-convex structure 2011 is located and the energy density of the battery monomer 100.

[0117] As an example, the maximum height dimension h of the concave-convex structure 2011 can be, but is not limited to, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.5 mm, etc.

[0118] In some embodiments, the first body section 201 includes a current collector, and the thickness dimension of the current collector is greater than or equal to 5 μm and less than or equal to 15 μm.

[0119] As an example, the thickness dimension of the current collector can be, but is not limited to, 5 μm, 7 μm, 10 μm, 12 μm, 15 μm, etc.

[0120] It can be understood that the thicker the thickness of the current collector, the better the pressure resistance effect it has, but the higher the space occupancy of the first body section 201 itself; the thinner the thickness of the current collector, the smaller the space occupancy, but the smaller the pressure resistance effect on the first body section 201, and the current collector that is too thin is not conducive to the setting of the concave-convex structure 2011.

[0121] Therefore, by setting the thickness dimension of the current collector in the above range, the effectiveness of the current collector being able to be provided with the concave-convex structure 2011 can be ensured, and the pressure resistance effect of the first body section 201 can also be improved, thereby improving the reliability of the battery monomer 100.

[0122] Optionally, the second body segment 202 can also include a current collector, which has a thickness dimension greater than or equal to 5 μm and less than or equal to 15 μm. Of course, the thickness dimension of the current collector of the second body segment 202 can also be set to other numerical ranges.

[0123] Optionally, the current collector can be made of copper foil or aluminum foil.

[0124] In some embodiments, the first body segment 201 further includes a conductive coating layer coated on the current collector.

[0125] The first body segment 201 can be coated with a conductive coating layer on both sides along the thickness direction Y, wherein each layer of the conductive coating layer has a thickness dimension greater than or equal to 2.5 μm and less than or equal to 7.5 μm.

[0126] For example, the thickness dimension of the conductive coating layer can be, but is not limited to, 2.5 μm, 4.5 μm, 7 μm, etc.

[0127] By setting the conductive coating layer, the static conductivity can be improved to reduce the contact resistance between the positive electrode tab 211 and the negative electrode tab 212, improve the conductivity of the current collector, and significantly improve the overall performance of the battery cell 100.

[0128] Optionally, the conductive coating layer can be made of nano-conductive graphite or carbon.

[0129] In some embodiments, the first body segment 201 further includes an active material layer coated on the current collector, which has a thickness dimension greater than or equal to 15 μm and less than or equal to 40 μm.

[0130] The first body segment 201 can be coated with an active material layer on both sides along the thickness direction Y, wherein each layer of the active material layer has a thickness dimension greater than or equal to 15 μm and less than or equal to 40 μm.

[0131] By setting the active material layer, the transmission efficiency of the electric charge of the first body segment 201 can be further improved, i.e., the efficiency of the charging and discharging of the battery cell 100 is improved, thereby improving the performance of the battery cell 100.

[0132] For example, the thickness dimension of the active material layer can be, but is not limited to, 15 μm, 20 μm, 30 μm, 40 μm, etc.

[0133] By setting the thickness dimension of the active material layer within the above range, the effectiveness of the current collector coated with the active material layer can be ensured to be provided with the concave-convex structure 2011.

[0134] Optionally, the active material layer can include materials such as iron sulfate and iron sulfite.

[0135] Optionally, the second body segment 202 can also include a conductive coating applied to the current collector, or the second body segment 202 can also include an active material layer applied to the current collector, the thickness of the active material layer is greater than or equal to 15 μm and less than or equal to 40 μm, or can also be set to other numerical ranges.

[0136] Referring to FIGS. 4, 5, 6 and 11, in some embodiments, the concave-convex structure 2011 is a strip structure, and the concave-convex structure 2011 is arranged to extend along at least one of the axial direction Z of the electrode assembly 20 and the winding direction X.

[0137] The concave-convex structure 2011 can be arranged as a strip structure extending along the axial direction Z, that is, before the electrode tab 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 is arranged to extend along the width direction W of the electrode tab 21, so that after the electrode tab 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the axial direction Z of the electrode assembly 20. In this way, the area of the concave-convex structure 2011 on the first body segment 201 can be increased, and the processing and manufacturing are facilitated, which is beneficial to improve the manufacturing efficiency.

[0138] Optionally, the number of the concave-convex structure 2011 extending along the axial direction Z is at least three, and is arranged to be spaced apart along the winding direction X, so as to improve the compression resistance of the first body segment 201.

[0139] The concave-convex structure 2011 can also be arranged as a strip structure extending along the winding direction X, that is, before the electrode tab 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 is arranged to extend along the length direction L of the electrode tab 21, so that after the electrode tab 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the winding direction X. In this way, the area of the concave-convex structure 2011 on the first body segment 201 can be increased, and the processing and manufacturing are facilitated, which is beneficial to improve the manufacturing efficiency.

[0140] Optionally, the concave-convex structure 2011 can be a point structure. Optionally, the concave-convex structure 2011 can also be a spiral strip structure.

[0141] In some embodiments, the orthographic projection of the concave-convex structure 2011 along the winding direction X is any one of a polygonal structure, a fan-shaped structure.

[0142] As shown in FIGS. 4 to 6, when the concave-convex structure 2011 is arranged to extend along the winding direction X of the electrode assembly 20, the orthographic projection of the concave-convex structure 2011 along the winding direction X is any one of a polygonal structure, a fan-shaped structure, that is, as shown in FIGS. 7 to 10, before the electrode tab 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 is arranged to extend along the length direction L of the electrode tab 21, and the orthographic projection of the concave-convex structure 2011 along the length direction L is any one of a polygonal structure, a fan-shaped structure.

[0143] In some embodiments, the projection of the concave-convex structure 2011 on the axial direction Z of the electrode assembly 20 is any one of a polygonal structure, a fan-shaped structure.

[0144] As shown in FIGS. 4, 5 and 11, when the concave-convex structure 2011 is arranged along the axial direction Z of the electrode assembly 20, the projection of the concave-convex structure 2011 on the axial direction Z is any one of a polygonal structure, a fan-shaped structure, that is, as shown in FIGS. 12 and 13, before the electrode tab 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 is arranged along the width direction W of the electrode tab 21, and the projection of the concave-convex structure 2011 on the width direction W is any one of a polygonal structure, a fan-shaped structure.

[0145] The battery monomer 100 provided by an embodiment of the present application is arranged in this way, which is conducive to improving the diversity of the concave-convex structure 2011, thereby facilitating the improvement of the diversity of the battery monomer 100.

[0146] The polygonal structure includes a triangle, a rectangle, a trapezoid, etc. The fan-shaped structure includes a semicircle, etc.

[0147] In some embodiments, the number of the concave-convex structures 2011 is set to be multiple. Such a design is conducive to improving the pressure resistance effect of the first body section 201 provided with the concave-convex structure 2011, and can better prevent the first body section 201 from being concave.

[0148] In some embodiments, the multiple concave-convex structures 2011 are distributed along the winding direction X.

[0149] As shown in FIGS. 11 to 13, that is, the multiple concave-convex structures 2011 are distributed along the length direction L of the electrode tab 21, so that after the electrode tab 21 is wound to form the electrode assembly 20, the multiple concave-convex structures 2011 are distributed along the winding direction X of the electrode assembly 20.

[0150] In some embodiments, the multiple concave-convex structures 2011 are distributed along the axial direction Z of the electrode assembly 20.

[0151] As shown in FIGS. 6 to 10, that is, the multiple concave-convex structures 2011 are distributed along the width direction W of the electrode tab 21, so that after the electrode tab 21 is wound to form the electrode assembly 20, the multiple concave-convex structures 2011 are distributed along the axial direction Z of the electrode assembly 20.

[0152] The battery monomer 100 provided by an embodiment of the present application is arranged in this way, which is conducive to improving the flexibility of use.

[0153] Alternatively, the multiple concave-convex structures 2011 can be distributed along both the axial direction Z and the winding direction X of the electrode assembly 20.

[0154] In some embodiments, the length dimension of the concave-convex structure 2011 is the same as the length dimension of the first body section 201 in the axial direction Z of the electrode assembly 20.

[0155] In one embodiment of the present application, the battery cell 100 is configured in this way, so that the central hole of the electrode assembly 20 corresponds to the concave-convex structure 2011 at each position in the axial direction Z, which is conducive to increasing the distribution area of the concave-convex structure 2011 on the first body section 201, so that the first body section 201 has better compression resistance.

[0156] Referring to FIG. 5, in a second aspect, the present application provides an electrode assembly 20, which includes a jellyroll 21 wound in a winding direction X, the jellyroll 21 including a first body section 201 and a second body section 202 connected along the winding direction X, the second body section 202 being arranged around the first body section 201, and the first body section 201 being provided with a concave-convex structure 2011.

[0157] In one embodiment of the present application, the electrode assembly 20 is provided with the concave-convex structure 2011 on the first body section 201 to provide support for the first body section 201, increase the compression resistance of the first body section 201, and the part of the first body section 201 provided with the concave-convex structure 2012 can deform to reduce or even absorb the expansion force transmitted to other positions of the first body section 201, preventing the first body section 201 from collapsing as a whole toward the central hole, which is conducive to improving the reliability and service life of the electrode assembly 20.

[0158] Referring to FIGS. 14-16, in a third aspect, the present application provides a winding needle 2 for forming an electrode assembly 20, the electrode assembly 20 including a jellyroll 21 wound in a winding direction X, the jellyroll 21 being provided with a concave-convex structure 2011, and the winding needle 2 including a winding body 2001 and a protruding portion 2002. The winding body 2001 is configured to wind the jellyroll 21. The protruding portion 2002 protruding from the outer circumferential surface of the winding body 2001 is configured to push the jellyroll 21 to form the concave-convex structure 2011.

[0159] The winding needle 2 is divided into two parts along the length direction of the winding needle 2, one part of the outer circumferential surface of which is machined to form the protruding portion 2002, and the other part is used to connect with an external driving mechanism, which controls the rotation of the winding needle 2 to drive the jellyroll 21 to rotate around the winding needle 2. After the electrode assembly 20 is formed, the winding needle 2 is extracted along the axial direction Z of the electrode assembly 20, i.e., the length direction of the winding needle 2, so that the electrode assembly 20 has a central hole and the jellyroll 21 at the position of the central hole has the concave-convex structure 2011.

[0160] Optionally, the protruding portion 2002 is integrally formed with the winding body 2001, which facilitates the processing efficiency and improves the connection strength between the two. Of course, the protruding portion 2002 and the winding body 2001 can also be provided separately, so that the winding body 2001 can be provided with protruding portions 2002 of different structures, which facilitates the use flexibility.

[0161] The winding needle 2 provided in an embodiment of the present application has a protruding portion 2011a protruding from the outer circumferential surface of the winding body 2001. The pole piece 21 wound by the winding needle 2 has a pole piece 21 near the center hole, which is pushed by the protruding portion 2011a to form a concave-convex structure 2011. The concave-convex structure 2011 can prevent the electrode assembly 20 near the center hole from collapsing.

[0162] Furthermore, by providing the winding needle 2 of the above-mentioned scheme to form the electrode assembly 20 with the concave-convex structure 2011, the effect of preventing the center hole from collapsing can be achieved without additional pipe structure, which facilitates processing and prevents the risk of displacement of the pole piece 21, and does not additionally increase the structure to affect the overall weight of the battery monomer 100, so as not to affect the energy density of the battery monomer 100. In addition, there is also enough space for the electrolyte to remain at the center hole of the electrode assembly 20, which facilitates the reliability of the battery monomer 100.

[0163] As shown in FIGS. 14 and 15, the protruding portion 2002 can be distributed along the length direction of the winding needle 2, so that the concave-convex structure 2011 on the electrode assembly 20 formed by the winding needle 2 is distributed along the axial direction Z. As shown in FIG. 16, the protruding portion 2002 can be distributed along the circumferential direction of the winding needle 2, so that the concave-convex structure 2011 on the electrode assembly 20 formed by the winding needle 2 is distributed along the winding direction X.

[0164] As shown in FIGS. 14 and 15, the protruding portion 2002 can be provided in a ring structure, and as shown in FIG. 16, the protruding portion 2002 can also be provided in a strip structure.

[0165] The cross-sectional shape of the protruding portion 2002 can be a rectangular structure, including a triangular structure, a quadrilateral structure, etc. The cross-sectional shape of the protruding portion 2002 can also be a sector structure.

[0166] According to some embodiments of the present application, the present application also provides a battery 1000, which includes the battery monomer 100 provided in any of the above embodiments.

[0167] According to some embodiments of the present application, the present application also provides a power consumption device, which includes the battery 1000 provided in any of the above embodiments, and the battery 1000 is used to provide electric energy.

[0168] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced equivalently. Such modifications or replacements do not change the essence of the corresponding technical solutions, which should be covered in the scope of the present application. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. 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, comprising: a housing; an electrode assembly disposed in the housing, the electrode assembly comprising a jelly-roll electrode; wherein the jelly-roll electrode comprises a first body segment and a second body segment connected along a winding direction, the second body segment is disposed around the first body segment, and the first body segment is provided with a concave-convex structure.

2. The battery cell of claim 1, wherein, The concave-convex structure comprises a convex portion and a concave portion, the convex portion protrudes from one side of the first body segment along a thickness direction of the jelly-roll electrode, the concave portion is recessed from the other side of the first body segment along the thickness direction, and the position of the convex portion corresponds to the position of the concave portion.

3. The battery cell of claim 1 or 2, wherein, The jelly-roll electrode is wound N turns from inside to outside along the winding direction, and the first body segment starts from the 1st turn and extends to the Mth turn, wherein 2≤M≤N.

4. The battery cell of claim 3, wherein, Along the winding direction, the concave-convex structures provided by the first body segments of adjacent two turns are engaged with each other.

5. The battery cell of any one of claims 1 to 4, wherein, The thickness dimension d of the first body segment and the maximum height dimension h of the concave-convex structure along the thickness direction of the jelly-roll electrode satisfy the relationship: 1 / 600≤d / h≤3 / 100.

6. The battery cell of claim 5, wherein, The maximum height dimension h satisfies the relationship: 0.5mm≤h≤3mm.

7. The battery cell of claim 5 or 6, wherein, The first body segment comprises a current collector, and the thickness dimension of the current collector is greater than or equal to 5μm and less than or equal to 15μm.

8. The battery cell of claim 7, wherein, The first body segment further comprises a conductive coating layer coated on the current collector, or the first body segment further comprises an active material layer coated on the current collector, and the thickness dimension of the active material layer is greater than or equal to 15μm and less than or equal to 40μm.

9. The battery cell of any one of claims 1 to 8, wherein, The concave-convex structure is a strip structure, and the concave-convex structure is disposed along at least one of an axial direction of the electrode assembly and the winding direction.

10. The battery cell of any one of claims 1 to 9, wherein, The orthographic projection of the concave-convex structure along the winding direction is any one of a polygonal structure and a sector structure; Or, the orthographic projection of the concave-convex structure along the axial direction of the electrode assembly is any one of a polygonal structure and a sector structure.

11. The battery cell of any one of claims 1 to 10, wherein, The number of the concave-convex structures is multiple.

12. The battery cell of claim 11, wherein, Multiple concave-convex structures are distributed along the winding direction and / or multiple concave-convex structures are distributed along the axial direction of the electrode assembly.

13. The battery cell of claim 11, wherein, In the axial direction of the electrode assembly, the length dimension of the concave-convex structure is the same as the length dimension of the first body segment.

14. An electrode assembly, wherein, The jelly-roll electrode comprises a first body segment and a second body segment connected along a winding direction, the second body segment is disposed around the first body segment, and the first body segment is provided with a concave-convex structure.

15. A winding needle for forming an electrode assembly, the electrode assembly comprising a jelly-roll of electrode sheets, the electrode sheets being provided with a concave-convex structure, wherein, The winding needle comprises: a winding body configured to wind the jelly-roll electrode; a protruding portion protruding from an outer circumferential surface of the winding body, the protruding portion is configured to push the jelly-roll electrode to form the concave-convex structure.

16. A battery, wherein, The battery cell according to any one of claims 1 to 13.

17. An electrical device, comprising: The battery according to claim 16 is used to provide electric energy.

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