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

Abstract

The utility model provides a battery monomer, an electrode assembly, a winding needle, a battery and an electric device. The battery monomer comprises a shell and the electrode assembly. The electrode assembly is arranged in the shell and comprises a wound electrode piece. The pole piece comprises a first body section and a second body section which are connected in the winding direction, the second body section is arranged around the first body section, and the first body section is provided with a concave-convex structure. The embodiment of the utility model is beneficial to improving the reliability of the battery monomer.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a battery cell, an electrode assembly, a winding needle, a battery, and an electrical device. Background Art

[0002] Battery cells are widely used in electronic devices, such as mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools, etc. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, ion battery cells, and secondary alkaline zinc-manganese battery cells, etc.

[0003] In the development of battery technology, how to improve the reliability of battery cells is a research direction in battery technology. Summary of the Utility Model

[0004] In view of the above problems, the present application provides a battery cell, an electrode assembly, a winding needle, a battery, and an electrical device, which is beneficial to improving the reliability of the battery cell.

[0005] In a first aspect, the present application provides a battery cell, including: a housing; an electrode assembly disposed within the housing, the electrode assembly including wound electrode sheets; wherein, the electrode sheet includes a first body section and a second body section connected along the winding direction, the second body section surrounds the first body section, and the first body section is provided with a concavo-convex structure.

[0006] In some embodiments of the first aspect, by providing a concavo-convex structure on the first body section, a supporting effect is provided to the whole of the first body section, increasing the compressive capacity of the first body section. Moreover, the part of the first body section provided with the concavo-convex structure can deform to reduce or even absorb the expansion force transmitted to other positions of the first body section, preventing the whole of the first body section from collapsing towards the central hole of the electrode assembly, so as to reduce the safety problems caused by the collision of the electrode sheets during the charge and discharge process of the battery cell, which is beneficial to improving the reliability and service life of the battery cell.

[0007] In some embodiments, the concavo-convex structure includes a convex part and a concave part, the convex part protrudes from one side of the first body section along the thickness direction of the electrode sheet, the concave part is recessed relative to the other side of the first body section 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 section provided with the concavo-convex structure to the expansion force of the electrode sheet can be further improved, thereby further preventing the first body section from collapsing.

[0008] In some embodiments, the pole piece is wound N turns from the inside to the outside along the winding direction, and the first body section starts from the first turn and extends to the Mth turn, where 2 ≤ M ≤ N. Winding the first body section with the concavo-convex structure at least two turns from the inside to the outside is beneficial to better improve the resistance effect of the first body section to the expansion force of the pole piece, thereby better preventing the first body section from collapsing.

[0009] In some embodiments, along the winding direction, the concavo-convex structures provided on the first body sections of adjacent two turns are meshed and matched with each other. By setting in this way, the occupied space of the first body section provided with the concavo-convex structure can be reduced, and further it is beneficial to reduce the influence on the energy density of the battery cell due to the concavo-convex structure.

[0010] In some embodiments, the thickness dimension d of the first body section and the maximum height dimension h of the concavo-convex structure in 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 section to the maximum height dimension h of the concavo-convex structure within the above range, it is possible to ensure that the first body section provided with the concavo-convex structure has sufficient bending resistance while improving the structural strength of the first body section.

[0011] In some embodiments, the maximum height dimension h satisfies the relationship: 0.5 mm ≤ h ≤ 3 mm. By setting the maximum height dimension h of the concavo-convex structure within the above range, it is beneficial to ensure that the first body section provided with the concavo-convex structure has sufficient compressive resistance.

[0012] In some embodiments, the first body section 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. By setting the thickness dimension of the current collector within the above range, the effectiveness of the current collector provided with the concavo-convex structure can be ensured.

[0013] In some embodiments, the first body section further includes a conductive coating coated on the current collector, or the first body section further includes an active material layer coated on the current collector, and the thickness dimension of the active material layer is greater than or equal to 15 μm and less than or equal to 40 μm. Through the above settings, the effectiveness of the current collector coated with the conductive coating or the active material layer provided with the concavo-convex structure can be ensured.

[0014] In some embodiments, the concavo-convex structure is a strip structure, and the concavo-convex structure extends along at least one of the axial direction and the winding direction of the electrode assembly. By setting in this way, it is convenient to process the concavo-convex structure on the first body section.

[0015] In some embodiments, the orthographic projection of the concave-convex structure in the winding direction is any one of a polygonal structure and a fan-shaped structure; alternatively, the orthographic projection of the concave-convex structure in the axial direction of the electrode assembly is any one of a polygonal structure and a fan-shaped structure. By setting in this way, it is beneficial to improve the diversity of the concave-convex structure, and thus beneficial to improve the diversity of the battery cell.

[0016] In some embodiments, the number of the concave-convex structures is set to be multiple. Such a design is beneficial to improving the compressive resistance effect of the first body section provided with the concave-convex structure, and can better prevent the first body section from being sunken.

[0017] In some embodiments, multiple concave-convex structures are distributed at intervals in the winding direction, and / or multiple concave-convex structures are distributed at intervals in the axial direction of the electrode assembly. By setting in this way, it is beneficial to improve the flexibility of use.

[0018] 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 section. By setting in this way, the distribution area of the concave-convex structure on the first body section can be increased, so that the first body section has a better compressive resistance effect.

[0019] In a second aspect, the present application provides an electrode assembly, including wound electrode sheets, the electrode sheets including a first body section and a second body section connected in the winding direction, the second body section surrounding the first body section, and the first body section being provided with a concave-convex structure.

[0020] In some embodiments of the second aspect, by providing a concave-convex structure on the first body section to provide a supporting effect on the first body section and increase the compressive resistance of the first body section, and the part of the first body section 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 section, preventing the first body section from collapsing towards the central hole as a whole, which is beneficial to improving the reliability and service life of the electrode assembly.

[0021] In a third aspect, the present application provides a winding needle for forming an electrode assembly, the electrode assembly including wound electrode sheets provided with a concave-convex structure, the winding needle including: a winding body configured to wind the electrode sheets; and a protruding portion protruding from the outer peripheral surface of the winding body, the protruding portion being configured to push against the electrode sheets to form the concave-convex structure.

[0022] In some embodiments of the third aspect, the winding needle is provided with a protruding portion protruding from the outer peripheral surface of the winding body. For the electrode assembly formed by winding with this winding needle, the electrode sheets near the central hole position can be pushed by the protruding portion to form a concave-convex structure, which is beneficial to preventing the problem of collapse at the position near the central hole of the electrode assembly.

[0023] In a fourth aspect, the present application provides a battery including the battery cell provided in any one of the embodiments of the first aspect.

[0024] In a fifth aspect, the present application provides an electrical device, including a battery provided in any embodiment of the fourth aspect, and the battery is used to provide electrical energy.

[0025] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically describes the specific embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0027] Figure 1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0028] Figure 2 is an exploded structural diagram of a battery provided in some embodiments of the present application;

[0029] Figure 3 is a schematic structural diagram of a battery module provided in some embodiments of the present application;

[0030] Figure 4 is an exploded structural diagram of a battery cell provided in some embodiments of the present application;

[0031] Figure 5 is a partial cross-sectional view of an electrode assembly in a battery cell provided in some embodiments of the present application;

[0032] Figure 6 is a partial structural diagram of a pole piece in a battery cell provided in some embodiments of the present application;

[0033] Figure 7 is Figure 6 a schematic cross-sectional structure diagram along A-A;

[0034] Figure 8 is a partial cross-sectional view of a pole piece in a battery cell provided in some embodiments of the present application;

[0035] Figure 9 is a partial cross-sectional view of a pole piece in a battery cell provided in some other embodiments of the present application;

[0036] Figure 10 is a partial cross-sectional view of a pole piece in a battery cell provided in some further embodiments of the present application;

[0037] Figure 11 Schematic diagram of the partial structure of the electrode in the battery cell provided in some other embodiments of the present application;

[0038] Figure 12 is Figure 11 Schematic diagram of the sectional structure along B-B;

[0039] Figure 13 Partial sectional view of the electrode in the battery cell provided in some other embodiments of the present application;

[0040] Figure 14 Schematic diagram of the structure of the winding pin provided in some embodiments of the present application;

[0041] Figure 15 Schematic diagram of the structure of the winding pin provided in some other embodiments of the present application;

[0042] Figure 16 Schematic diagram of the structure of the winding pin provided in some other embodiments of the present application.

[0043] The reference numerals in the specific embodiments are as follows:

[0044] 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;

[0045] 10 - outer shell; 101 - end cover; 102 - housing; 10a - electrode terminal;

[0046] 20 - electrode assembly; 21 - electrode; 211 - positive electrode; 212 - negative electrode; 201 - first body section; 2011 - concavo-convex structure; 2011a - convex part; 2011b - concave part; 202 - second body section; 22 - separator;

[0047] 2 - winding pin; 2001 - winding body; 2002 - protruding part;

[0048] X - winding direction; Y - thickness direction; Z - axial direction; L - length direction; W - width direction. Specific embodiments

[0049] The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0050] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should have the ordinary meanings understood by those skilled in the art to which the embodiments of the present application belong.

[0051] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present application.

[0052] In addition, technical terms such as "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0053] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0054] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may 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 being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0055] At present, from the perspective of the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in many fields such as military equipment and aerospace. With the continuous expansion of the application fields of batteries, the market demand is also continuously increasing.

[0056] The development of battery technology needs to consider various design factors at the same time. For example, performance parameters such as battery life, energy density, discharge capacity, charge and discharge rate, etc. In addition, the reliability of the battery also needs to be considered.

[0057] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack, etc.

[0058] The battery cell can be a secondary battery cell, and a secondary battery cell refers to a battery cell that can activate the active material through charging after discharging the battery cell and continue to be used.

[0059] In the charging and discharging cycle process of the battery in the related technology, the cathode and anode material particles in the battery cell will expand. Since there is a central hole formed at the center position of the battery cell formed by winding, when the electrode sheet expands during the cycle process, there is no support at the position where the inner ring electrode sheet faces the central hole, resulting in a collapse problem at the central hole position, causing damage to the electrode assembly, thereby reducing the reliability of the battery cell.

[0060] Based on the above technical problems, the embodiments of the present application provide a battery cell, which includes a housing and an electrode assembly. The electrode assembly is disposed in the housing, and the electrode assembly includes wound electrode sheets. Among them, the electrode sheet includes a first body section and a second body section connected along the winding direction, the second body section surrounds the first body section, and the first body section is provided with a concavo-convex structure.

[0061] The first body section is disposed close to the central hole of the electrode assembly. By providing a concavo-convex structure on the first body section, a supporting effect is provided for the entire first body section, increasing the compressive capacity of the first body section. Moreover, the part of the first body section provided with the concavo-convex structure can deform to reduce or even absorb the expansion force transmitted to other positions of the first body section, preventing the entire first body section from collapsing towards the central hole of the electrode assembly, so as to reduce the safety problems caused by the collision of the electrode sheets during the charging and discharging process of the battery cell, which is beneficial to improving the reliability and service life of the battery cell.

[0062] The technical solutions described in the embodiments of the present application are applicable to various battery-powered devices, such as mobile phones, portable devices, laptops, battery cars, electric toys, power tools, electric vehicles, ships, and spacecrafts, etc. For example, spacecrafts include airplanes, rockets, space shuttles, and spaceships, etc.

[0063] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the devices described above, but can also be applicable to all battery-powered devices. However, for the sake of brevity in description, the following embodiments will be described by taking vehicles as an example.

[0064] For example, as Figure 1 shown, Figure 1 FIG. 10 is a schematic structural 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. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or an extended-range electric vehicle, etc. A motor 3000, a controller 2000, and a battery 1000 can be arranged inside the vehicle 1. The controller 2000 is used 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 end, or the rear end of the vehicle 1. The battery 1000 can be used for power supply of the vehicle 1. For example, the battery 1000 can be used as the operating power source of the vehicle 1 and be used for the circuit system of the vehicle 1, such as the working power requirements for starting, navigation, and running of the vehicle 1. In another embodiment of the present application, the battery 1000 can not only be used as the operating power source of the vehicle 1, but also be used as the driving power source of the vehicle 1 to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1.

[0065] As Figure 2 and Figure 3 shown, in order to meet different power usage requirements, the battery 1000 can include a plurality of battery cells 100. Among them, the plurality of battery cells 100 can be connected in series, in parallel, or in a series-parallel combination. The series-parallel combination means a combination of series and parallel connections. The battery 1000 can also be referred to as a battery pack. Optionally, the plurality of battery cells 100 can first be connected in series, in parallel, or in a series-parallel combination to form a battery module 100a, and then the plurality of battery modules 100a are connected in series, in parallel, or in a series-parallel combination to form the battery 1000. That is to say, the plurality of battery cells 100 can directly form the battery 1000, or can first form the battery module 100a, and then the battery modules form the battery 1000.

[0066] In the present application, the battery cell 100 can include a lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, etc., and the embodiments of the present application do not limit this. The battery cell 100 can be in a cylindrical shape, a flat shape, a cuboid shape, or other shapes, and the embodiments of the present application also do not limit this.

[0067] As Figure 2As shown, a battery 1000 according to an embodiment of the present application further includes a box body 200. A plurality of battery cells 100 are accommodated in the box body 200, and the box body 200 can protect the battery cells 100.

[0068] The box body 200 can be a simple three-dimensional structure such as a separate cuboid, cylinder, sphere, etc., or a complex three-dimensional structure composed of a combination of simple three-dimensional structures such as a cuboid, cylinder, sphere, etc. The embodiments of the present application do not limit this. The material of the box body 200 can be alloy materials such as aluminum alloy and ferroalloy, or polymer materials such as polycarbonate and polyisocyanurate foam plastic, or composite materials such as glass fiber reinforced epoxy resin. The embodiments of the present application do not limit this either.

[0069] The box body 200 is used to accommodate the battery cells 100, and the box body 200 can be of various structures. In some embodiments, the box body 200 can include a first box body part 210 and a second box body part 220. The first box body part 210 and the second box body part 220 are covered with each other, and the first box body part 210 and the second box body part 220 jointly define an accommodation cavity 200a for accommodating the battery cells 100. Both the first box body part 210 and the second box body part 220 can be hollow structures with an opening on one side. The opening side of the first box body part 210 is covered with the opening side of the second box body part 220 to form the box body 200 with the accommodation cavity 200a. Of course, the first box body part 210 and the second box body part 220 can be of various shapes, such as a cylinder, a cuboid, etc. The first box body part 210 can also be a plate-like structure, and the second box body part 220 can be a hollow structure with an opening on one side.

[0070] To improve the sealing performance after the connection between the first box body part 210 and the second box body part 220, a sealing member such as sealant, sealing ring, etc. can also be provided between the first box body part 210 and the second box body part 220.

[0071] Please refer to Figures 4 to 13 , according to an embodiment of the present application, a battery cell 100 is provided, including a housing 10 and an electrode assembly 20. The electrode assembly 20 is disposed in the housing 10, and the electrode assembly 20 includes wound electrode sheets 21. Among them, the electrode sheet 21 includes a first body section 201 and a second body section 202 connected along the winding direction X. The second body section 202 is disposed around the first body section 201, and the first body section 201 is provided with a concavo-convex structure 2011.

[0072] The housing 10 is a component for forming the internal environment of the battery cell 100. The internal environment formed can be used to accommodate the electrode assembly 20, and can also be used to accommodate the electrolyte and other components. Optionally, the housing 10 can be made of, but not limited to, metal or non-metal materials. For example, the metal material can be copper, aluminum, or stainless steel, etc.; the non-metal material can be polyethylene, polypropylene, or polyvinyl chloride, etc.

[0073] The electrode assembly 20 is a component in the battery cell 100 where an electrochemical reaction occurs. The housing 10 can contain one or more electrode assemblies 20.

[0074] The electrode assembly 20 includes wound electrode sheets 21. Specifically, the electrode sheets 21 can include a positive electrode sheet 211 and a negative electrode sheet 212 with opposite polarities. The portions of the positive electrode sheet 211 and the negative electrode sheet 212 that have the active material constitute the main body of the electrode assembly 20, and the portions of the positive electrode sheet 211 and the negative electrode sheet 212 that do not have the active material each constitute an electrode tab. The positive electrode tab and the negative electrode tab can be located at one end of the main body together or at both ends of the main body respectively. During the charging and discharging process of the battery 1000, the positive electrode active material and the negative electrode active material react with the electrolyte, and the electrode tabs are connected to the electrode terminals 10a to form a current loop. The positive electrode sheet 211 and the negative electrode sheet 212 can also be provided with a separator 22. In some embodiments, a separator 22 may not be provided between the positive electrode sheet 211 and the negative electrode sheet 212.

[0075] The electrode assembly 20 can include any one of a cylindrical electrode assembly, a rectangular electrode assembly, and an oval electrode assembly.

[0076] Optionally, the negative electrode sheet 212 can include a first body segment 201 and a second body segment 202 connected along the winding direction X. That is, in the wound electrode assembly 20, the negative electrode sheet 212 is disposed closer to the central hole of the electrode assembly 20 than the positive electrode sheet 211; alternatively, the positive electrode sheet 211 can also include a first body segment 201 and a second body segment 202 connected along the winding direction X.

[0077] Exemplarily, as Figure 4 and Figure 5 shown, the positive electrode sheet 211 includes a first body segment 201 and a second body segment 202 connected along the winding direction X.

[0078] As Figure 6 and Figure 11 shown, Figure 6 and Figure 11 can both represent the structure of the electrode sheet 21 when it is not wound. Among them, as Figure 4 and Figure 5In the electrode assembly 20 shown, the electrode tab 21 includes a first body segment 201 and a second body segment 202 connected along the winding direction X, and after winding, the electrode tab 21 encloses a central hole. It can be understood that in the electrode tab 21 as shown in Figure 6 and Figure 11 shown, the electrode tab 21 includes a first body segment 201 and a second body segment 202 connected along the length direction L. That is to say, before the electrode tab 21 is wound, a concavo-convex structure 2011 can be provided on the first body segment 201 of the electrode tab 21.

[0079] For the batteries in the related art, in order to solve the problem of collapse at the position of the central hole, a tube body is often inserted at the central hole after the electrode tab is wound to form an electrode assembly. However, the insertion process of the tube body is difficult and not easy to implement, and it is easy to cause friction with the electrode tab and displacement of the electrode tab. The additional tube body will also cause an increase in the overall weight of the battery cell, reduce the energy density. Moreover, the tube body occupies the space of the winding through-hole, resulting in insufficient space for the electrolyte to remain.

[0080] Therefore, through the above settings, that is, the first body segment 201 and the second body segment 202 are divided on the unwound electrode tab 21 in advance, and then the concavo-convex structure 2011 is processed on the first body segment 201, which is convenient for processing and manufacturing, and can also prevent the risk of displacement of the electrode tab 21, and will not additionally increase the structure to affect the overall weight of the battery cell 100, and thus will not affect the energy density of the battery cell 100. In addition, after the concavo-convex structure 2011 is provided, there is also enough space at the central hole of the electrode assembly 20 for the electrolyte to remain, which is beneficial to improving the reliability of the battery cell 100. Specifically, the first body segment 201 and the second body segment 202 can be divided on the electrode tab 21 according to user requirements.

[0081] Among them, the concavo-convex structure 2011 can be understood as that at least one of the convex portion 2011a and the concave portion 2011b is provided on at least one side of the first body segment 201 along the thickness direction Y of the electrode tab 21. That is to say, the two side surfaces of the first body segment 201 along the thickness direction Y are uneven.

[0082] The thickness direction Y of the electrode tab 21 can also be understood as the radial direction of the electrode assembly 20 as shown in Figure 4 and Figure 5 shown.

[0083] Optionally, the concavo-convex structure 2011 and the first body segment 201 are integrally formed. The concavo-convex structure 2011 can be formed from the first body segment 201 by stretch forming or extrusion forming processes, without adding new components, which will not affect the weight and energy density of the battery cell 100. Moreover, the electrode sheet 21 with the concavo-convex structure 2011 can be obtained before winding, without setting the concavo-convex structure 2011 after the electrode assembly 20 is wound and formed, so as to avoid displacement of the electrode sheet 21. The concavo-convex structure 2011 also does not occupy the central hole, which is beneficial to improving the reliability and service life of the battery cell 100.

[0084] Specifically, the concavo-convex structure 2011 can be formed by stamping the first body segment 201 along its own thickness direction Y, so that the structural strength of the first body segment 201 at the position where the concavo-convex structure 2011 is provided is greater than that of other positions of the first body segment 201, which is beneficial to improving the compressive capacity of the first body segment 201 to delay or even avoid its collapse towards the central hole position. Moreover, there is a deformation space at the position of the concavo-convex structure 2011 of the first body segment 201, and the part of the first body segment 201 located at the concavo-convex structure 2011 can deform to reduce or even absorb the expansion force transmitted to other positions of the first body segment 201, further preventing the whole first body segment 201 from collapsing towards the central hole.

[0085] In the battery cell 100 provided by an embodiment of the present application, by providing the concavo-convex structure 2011 on the first body segment 201, a supporting effect is provided for the whole first body segment 201 to increase the compressive capacity of the first body segment 201. Moreover, the part of the first body segment 201 located at the concavo-convex structure 2011 can deform to reduce or even absorb the expansion force transmitted to other positions of the first body segment 201, preventing the whole first body segment 201 from collapsing towards the central hole, so as to reduce the safety problems caused by the collision of the electrode sheet 21 during the charge and discharge process of the battery cell 100, which is beneficial to improving the reliability and service life of the battery cell 100.

[0086] As Figure 4 shown, the housing 10 may include an end cap 101 and a housing body 102. The housing body 102 has an opening, and the end cap 101 is connected to the housing body 102 and closes the opening. The end cap 101 and the housing body 102 can be independent components. An opening can be provided on the housing body 102, and the end cap 101 is covered at the opening to form the internal environment of the battery cell 100.

[0087] The shell 102 can be in various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism shape, etc. Specifically, the shape of the shell 102 can be determined according to the specific shape and size of the electrode assembly 2020. The shell 102 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0088] In some embodiments, the shell 102 can be a rectangular shell 102, and the electrode assembly 20 can correspondingly be a rectangular electrode assembly 20. The shell 102 includes a bottom wall and four side walls arranged around the edge of the bottom wall. The four side walls form an opening at one end facing away from the bottom wall, and the end cover 101 is connected to the four side walls to close the opening.

[0089] In some embodiments, the shell 102 can be a circular shell 102, and the electrode assembly 20 can correspondingly be a cylindrical electrode assembly 20. The shell 102 includes a bottom wall and a peripheral wall arranged around the edge of the bottom wall. The peripheral wall forms an opening at one end away from the bottom wall, and the end cover 101 is connected to the peripheral wall to close the opening.

[0090] The end cap 101 refers to a component that covers the opening of the housing 102 to isolate the internal environment of the battery cell 100 from the external environment. Without limitation, the shape of the end cap 101 can be adapted to the shape of the housing 102 to match the housing 102. The material of the end cap 101 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0091] See also Figure 8 and Figure 9 In some embodiments, the concave-convex structure 2011 includes a convex portion 2011a and a concave portion 2011b, the convex portion 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 portion 2011b is concave relative to the other side of the first body segment 201 along the thickness direction Y, and the position of the convex portion 2011a corresponds to the position of the concave portion 2011b.

[0092] The positions of the convex portion 2011a and the concave portion 2011b correspond to each other. It can be understood that the orthographic projection of the convex portion 2011a in the thickness direction Y and the orthographic projection of the concave portion 2011b in the thickness direction Y are overlapped.

[0093] like Figure 8 As shown in FIG. 1 , a convex portion 2011a and a concave portion 2011b opposite thereto can be regarded as a concave-convex structure 2011, that is, the concave-convex structure 2011 includes a convex portion 2011a and a concave portion 2011b; or Figure 9As shown, two consecutive convex portions 2011a and their respective opposite concave portions 2011b can also be regarded as an uneven structure 2011, that is, the uneven structure 2011 includes two convex portions 2011a and two concave portions 2011b; alternatively, multiple consecutive convex portions 2011a and their respective opposite multiple concave portions 2011b can also be regarded as an uneven structure 2011. In an embodiment of the present application, an uneven structure 2011 includes a convex portion 2011a and a concave portion 2011b.

[0094] The battery cell 100 provided by an embodiment of the present application is configured in this way, which can further improve the resistance effect of the portion of the first body segment 201 provided with the uneven structure 2011 against the expansion force of the electrode sheet 21, thereby further preventing the first body segment 201 from collapsing and improving the reliability of the battery cell 100.

[0095] Optionally, the convex portion 2011a protrudes from one side of the first body segment 201 in the thickness direction Y towards the second body segment 202, and the concave portion 2011b is recessed from one side of the body segment in the thickness direction Y towards the second body segment 202.

[0096] Optionally, the number of the uneven structures 2011 can be set to one or two. Of course, it can also be set to multiple.

[0097] Optionally, two or more uneven structures 2011 can be distributed at intervals or can be continuously arranged. The continuous arrangement of two or more uneven structures 2011 means that the uneven structures 2011 on the first body segment 201 as a whole present a wavy shape.

[0098] The uneven structure 2011 can be in various shapes. For example, the convex portion 2011a can be a rectangular protrusion extending along a rectangular trajectory, and the concave portion 2011b is correspondingly set as a rectangular groove extending along a rectangular trajectory; alternatively, the convex portion 2011a can be a U-shaped protrusion extending along a U-shaped trajectory, and the concave portion 2011b is correspondingly set as a U-shaped groove extending along a U-shaped trajectory; alternatively, the protrusion can be a V-shaped protrusion extending along a V-shaped trajectory, and the concave portion 2011b is correspondingly set as a V-shaped groove extending along a V-shaped trajectory.

[0099] In some embodiments, the electrode sheet 21 is wound N circles from the inside out in the winding direction X, and the first body segment 201 starts from the first circle and extends to the Mth circle, where 2 ≤ M ≤ N.

[0100] The pole piece 21 is wound N turns from the inside out along the winding direction X. The inner side of the wound electrode assembly 20 has a central hole. The first body segment 201 starts from the first turn and extends to the Mth turn. It can be understood that starting from one end of the first body segment 201 along the length direction L of the pole piece 21 away from the second body segment 202 and winding, the formed electrode assembly 20, from the central hole of the electrode assembly 20 towards the outer peripheral surface of the electrode assembly 20, the first to the Mth turns are all the first body segments 201 provided with the concavo-convex structure 2011.

[0101] 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 concavo-convex structure 2011. Of course, the value of M can also be set to 2.5, 3, etc.

[0102] In a battery cell 100 provided by an embodiment of the present application, the first body segment 201 having the concavo-convex structure 2011 is wound at least two turns from the inside out, which is beneficial to better improving 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.

[0103] In other embodiments, as Figure 5 shown, the pole piece 21 can also be set as the first body segment 201 only at the position of the first turn, which can also play a role in preventing the first body segment 201 from collapsing.

[0104] In some embodiments, along the winding direction X, the concavo-convex structures 2011 provided on the adjacent two turns of the first body segment 201 are engaged and matched with each other.

[0105] The engagement and cooperation of the concavo-convex structures 2011 can be understood as that the concavo-convex structure 2011 of the inner first body segment 201 and the concavo-convex structure of the outer first body are at least partially overlapped in the winding direction X, so as to reduce the radial space occupied by them.

[0106] By setting in this way, the occupied space of the first body segment 201 provided with the concavo-convex structure 2011 can be reduced, and further it is beneficial to reduce the influence of the concavo-convex structure 2011 on the energy density of the battery cell 100.

[0107] Exemplarily, the first body segment 201 starts from the first turn and extends to the second turn. The convex portion 2011a of the first turn extends into the concave portion 2011b of the second turn, that is, the concavo-convex structure 2011 of the first turn is engaged and matched with the concavo-convex structure 2011 of the second turn.

[0108] Please refer to Figure 7 That is Figure 10, in some embodiments, along the thickness direction Y of the electrode tab 21, the thickness dimension d of the first body segment 201 and the maximum height dimension h of the concavo-convex structure 2011 satisfy the relationship: 1 / 600 ≤ d / h ≤ 3 / 100.

[0109] The maximum height dimension h of the concavo-convex structure 2011 refers to the distance from one end to the other end of the concavo-convex structure 2011 in the thickness direction Y.

[0110] As an 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.

[0111] Wherein, the thickness dimension d of the first body segment 201 at different positions may be the same or different.

[0112] It can be understood that the thickness dimension d of the first body segment 201 affects its own structural performance, while the maximum height dimension h of the concavo-convex structure 2011 affects the structural strength of the first body segment 201 at its location. Therefore, to prevent the structural performance of the first body segment 201 after the concavo-convex structure 2011 is provided from being affected, by setting the ratio of the thickness dimension d of the first body segment 201 to the maximum height dimension h of the concavo-convex structure 2011 within the above range, the structural performance of the first body segment 201 itself can be effectively improved.

[0113] For the battery cell 100 provided in an embodiment of the present application, by setting the ratio of the thickness dimension d of the first body segment 201 to the maximum height dimension h of the concavo-convex structure 2011 within the above range, it is possible to ensure that the first body segment 201 provided with the concavo-convex structure 2011 has sufficient bending resistance effect while being beneficial to improving the structural strength of the first body segment 201.

[0114] In some embodiments, the maximum height dimension h satisfies the relationship: 0.5 mm ≤ d / h ≤ 3 mm.

[0115] As an example, the maximum height dimension h of the concavo-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.

[0116] It can be understood that the higher the height of the concavo-convex structure 2011, the better the supporting effect on the structural strength of the first body segment 201. However, the higher the space occupancy rate of the concavo-convex structure 2011 itself; the smaller the height of the concavo-convex structure 2011, the smaller its space occupancy rate, but the smaller the supporting effect on the structural strength of the first body segment 201.

[0117] Therefore, by setting the maximum height dimension h of the concave-convex structure 2011 within the above range, it is possible to ensure that the concave-convex structure 2011 has sufficient strengthening effect while reducing the impact on the energy density of the battery cell 100.

[0118] Furthermore, when the maximum height dimension h satisfies the relationship: 1mm ≤ d / h ≤ 2.5mm, the balance between the structural strength at the position of the concave-convex structure 2011 and the energy density of the battery cell 100 can be further optimized.

[0119] As an example, the maximum height dimension h of the concave-convex structure 2011 can be, but is not limited to, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.5mm, etc.

[0120] 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 5μm and less than or equal to 15μm.

[0121] As an example, the thickness dimension of the current collector can be, but is not limited to, 5μm, 7μm, 10μm, 12μm, 15μm, etc.

[0122] It can be understood that the thicker the current collector, the better its compressive effect. However, it will also result in a higher space occupancy rate of the first body section 201 itself; the thinner the current collector, the smaller its space occupancy rate. However, the compressive effect on the first body section 201 will also be smaller, and an overly thin current collector is not conducive to setting the concave-convex structure 2011.

[0123] Therefore, setting the thickness dimension of the current collector within the above range is conducive to ensuring the effectiveness of the concave-convex structure 2011 that can be provided on the current collector, and is also conducive to improving the compressive effect of the first body section 201, thereby facilitating the improvement of the reliability of the battery cell 100.

[0124] Optionally, the second body section 202 can also include a current collector, and the thickness dimension of its current collector is greater than or equal to 5μm and less than or equal to 15μm. Of course, the thickness dimension of the current collector of the second body section 202 can also be set to other numerical ranges.

[0125] Optionally, the current collector can be made of copper foil or aluminum foil.

[0126] In some embodiments, the first body section 201 further includes a conductive coating coated on the current collector.

[0127] Both sides of the first body segment 201 along the thickness direction Y may be coated with a conductive coating, wherein the thickness of each layer of the conductive coating is greater than or equal to 2.5 μm and less than or equal to 7.5 μm.

[0128] As an example, the thickness of the conductive coating may be, but is not limited to, 2.5 μm, 4.5 μm, 7 μm, etc.

[0129] By providing a conductive coating, the static conductive performance can be improved to reduce the contact resistance between the positive electrode plate 211 and the negative electrode plate 212 , improve the conductive performance of the current collector, and significantly improve the overall performance of the battery cell 100 .

[0130] Optionally, the conductive coating may be made of nano-conductive graphite or carbon.

[0131] In some embodiments, the first body segment 201 further includes an active material layer coated on the current collector, and the thickness of the active material layer is greater than or equal to 15 μm and less than or equal to 40 μm.

[0132] Both sides of the first body segment 201 along the thickness direction Y may be coated with an active material layer, wherein the thickness of each active material layer is greater than or equal to 15 μm and less than or equal to 40 μm.

[0133] By providing the active material layer, the charge transfer efficiency of the first body segment 201 can be further improved, that is, it is beneficial to improve the efficiency of charging and discharging of the battery cell 100, thereby improving the performance of the battery cell 100.

[0134] As an example, the thickness of the active material layer may be, but is not limited to, 15 μm, 20 μm, 30 μm, 40 μm, etc.

[0135] By setting the thickness dimension of the active material layer within the above range, the effectiveness of providing the concavo-convex structure 2011 on the current collector coated with the active material layer can be ensured.

[0136] Optionally, the active material layer may include materials such as ferrous sulfate and ferrous sulfite.

[0137] Optionally, the second body segment 202 may also include a conductive coating coated on the current collector, or the second body segment 202 may also include an active material layer coated on 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 it can also be set to other numerical ranges.

[0138] See also Figure 4 , Figure 5 , Figure 6 and Figure 11, in some embodiments, the concave-convex structure 2011 is a strip-shaped structure, and the concave-convex structure 2011 extends along at least one of the axial direction Z and the winding direction X of the electrode assembly 20.

[0139] The concave-convex structure 2011 can be set as a strip-shaped structure extending along the axial direction Z. That is to say, before the pole piece 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the width direction W of the pole piece 21, so that after the pole piece 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. By setting in this way, the area of the concave-convex structure 2011 on the first body section 201 can be increased, and it is convenient for processing and manufacturing, which is beneficial to improving the production efficiency.

[0140] Optionally, the number of the concave-convex structures 2011 extending along the axial direction Z is at least three, and they are distributed at intervals along the winding direction X to improve the compressive effect of the first body section 201.

[0141] The concave-convex structure 2011 can also be set as a strip-shaped structure extending along the winding direction X. That is to say, before the pole piece 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the length direction L of the pole piece 21, so that after the pole piece 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the winding direction X. By setting in this way, the area of the concave-convex structure 2011 on the first body section 201 can be increased, and it is convenient for processing and manufacturing, which is beneficial to improving the production efficiency.

[0142] Optionally, the concave-convex structure 2011 can be a dot-shaped structure. Optionally, the concave-convex structure 2011 can also be a spiral strip-shaped structure.

[0143] In some embodiments, the orthographic projection of the concave-convex structure 2011 in the winding direction X is any one of a polygonal structure and a fan-shaped structure.

[0144] As Figures 4 to 6 shown, when the concave-convex structure 2011 extends along the winding direction X of the electrode assembly 20, the orthographic projection of the concave-convex structure 2011 in the winding direction X is any one of a polygonal structure and a fan-shaped structure. That is to say, as Figures 7 to 10 shown, before the pole piece 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the length direction L of the pole piece 21, and the orthographic projection of the concave-convex structure 2011 in the length direction L is any one of a polygonal structure and a fan-shaped structure.

[0145] In some embodiments, the orthographic projection of the concave-convex structure 2011 in the axial direction Z of the electrode assembly 20 is any one of a polygonal structure and a fan-shaped structure.

[0146] As Figure 4 , Figure 5 andFigure 11 As shown, when the concave-convex structure 2011 extends along the axial direction Z of the electrode assembly 20, the orthographic projection of the concave-convex structure 2011 in the axial direction Z is any one of a polygonal structure and a sector structure. That is to say, as Figure 12 and Figure 13 shown, before the pole piece 21 is wound to form the electrode assembly 20, the concave-convex structure 2011 extends along the width direction W of the pole piece 21, and the orthographic projection of the concave-convex structure 2011 in the width direction W is any one of a polygonal structure and a sector structure.

[0147] The battery cell 100 provided by an embodiment of the present application is arranged in this way, which is beneficial to improving the diversity of the concave-convex structure 2011, and thus beneficial to improving the diversity of the battery cell 100.

[0148] Among them, the polygonal structure includes a triangle, a rectangle, a trapezoid, etc. The sector structure includes a semi-circle, etc.

[0149] In some embodiments, the number of the concave-convex structures 2011 is set to be multiple. Such a design is beneficial to improving the compressive 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 sunken.

[0150] In some embodiments, the multiple concave-convex structures 2011 are spaced apart along the winding direction X.

[0151] As Figures 11 to 13 shown, that is to say, the multiple concave-convex structures 2011 are spaced apart along the length direction L of the pole piece 21, so that after this pole piece 21 is wound to form the electrode assembly 20, the multiple concave-convex structures 2011 are spaced apart along the winding direction X of the electrode assembly 20.

[0152] In some embodiments, the multiple concave-convex structures 2011 are spaced apart along the axial direction Z of the electrode assembly 20.

[0153] As Figures 6 to 10 shown, that is to say, the multiple concave-convex structures 2011 are spaced apart along the width direction W of the pole piece 21, so that after this pole piece 21 is wound to form the electrode assembly 20, the multiple concave-convex structures 2011 are spaced apart along the axial direction Z of the electrode assembly 20.

[0154] The battery cell 100 provided by an embodiment of the present application is arranged in this way, which is beneficial to improving the flexibility of use.

[0155] Optionally, the multiple concave-convex structures 2011 can be spaced apart both along the axial direction Z of the electrode assembly 20 and along the winding direction X.

[0156] In some embodiments, along the axial direction Z of the electrode assembly 20, the length dimension of the concave-convex structure 2011 is the same as the length dimension of the first body segment 201.

[0157] The battery cell 100 provided by an embodiment of the present application is arranged in this way, so that the central hole of the electrode assembly 20 corresponds to the concave-convex structure 2011 at each position along the axial direction Z, which is beneficial to increasing the distribution area of the concave-convex structure 2011 on the first body segment 201, so that the first body segment 201 has a better compressive effect.

[0158] Please refer to Figure 5 , in a second aspect, the present application provides an electrode assembly 20, including wound electrode sheets 21. The electrode sheets 21 include a first body segment 201 and a second body segment 202 connected along the 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.

[0159] The electrode assembly 20 provided by an embodiment of the present application is provided with a concave-convex structure 2011 on the first body segment 201 to provide a supporting effect on the first body segment 201 and increase the compressive capacity of the first body segment 201. Moreover, the part of the first body segment 201 provided with the concave-convex structure 2022 can deform to reduce or even absorb the expansion force transmitted to other positions of the first body segment 201, preventing the first body segment 201 from collapsing towards the central hole as a whole, which is beneficial to improving the reliability and service life of the electrode assembly 20.

[0160] Please refer to Figures 14 to 16 , in a third aspect, the present application provides a winding needle 2 for forming the electrode assembly 20. The electrode assembly 20 includes wound electrode sheets 21 provided with a concave-convex structure 2011. The winding needle 2 includes a winding body 2001 and a protruding part 2002. The winding body 2001 is configured to wind the electrode sheets 21. The protruding part 2002 protruding from the outer peripheral surface of the winding body 2001 is configured to push against the electrode sheets 21 to form the concave-convex structure 2011.

[0161] The winding needle 2 is divided into two parts along its own length direction. The outer peripheral surface of one part is processed to form the protruding part 2002, and the other part is used to connect with an external driving mechanism. The external driving mechanism controls the rotation of the winding needle 2 to drive the electrode sheets 21 to rotate around the winding needle 2. After the electrode assembly 20 is formed, the winding needle 2 is withdrawn along the axial direction Z of the electrode assembly 20, that is, the length direction of the winding needle 2, so that the electrode assembly 20 has a central hole, and the electrode sheets 21 at the central hole position have a concave-convex structure 2011.

[0162] Optionally, the protruding portion 2002 is integrally formed with the winding body 2001, which is beneficial to improving the processing efficiency and the connection strength between the two. Of course, the protruding portion 2002 and the winding body 2001 can also be provided separately, so that different structures of the protruding portion 2002 can be provided on the winding body 2001, which is beneficial to improving the use flexibility.

[0163] For the winding pin 2 provided by an embodiment of the present application, the winding pin 2 is provided with a convex portion 2011a protruding from the outer peripheral surface of the winding body 2001. For the pole piece 21 wound by using this winding pin 2, the pole piece 21 near the central hole is pushed by the convex portion 2011a to form an uneven structure 2011, and the uneven structure 2011 can prevent the collapse problem at the position of the electrode assembly 20 near the central hole.

[0164] Moreover, by providing the winding pin 2 of the above solution to form the electrode assembly 20 with the uneven structure 2011, the effect of preventing the collapse of the central hole position can be achieved without additionally increasing the tube structure, which is convenient for processing, 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 cell 100, and thus will not affect the energy density of the battery cell 100. In addition, there is enough space at the central hole of the electrode assembly 20 to retain the electrolyte, which is beneficial to improving the reliability of the battery cell 100.

[0165] As Figure 14 and Figure 15 shown, the protruding portions 2002 can be distributed at intervals along the length direction of the winding pin 2, and thus the uneven structures 2011 on the electrode assembly 20 formed by the winding pin 2 are distributed at intervals along the axial direction Z; as Figure 16 shown, the protruding portions 2002 can be distributed at intervals along the circumferential direction of the winding pin 2, and thus the uneven structures 2011 on the electrode assembly 20 formed by the winding pin 2 are distributed at intervals along the winding direction X.

[0166] As Figure 14 and Figure 15 shown, the protruding portion 2002 can be set as an annular structure, as Figure 16 shown, the protruding portion 2002 can also be set as a strip structure.

[0167] The cross-sectional shape of the protruding portion 2002 can be a rectangular structure, and the rectangular structure includes a triangle, a quadrilateral, etc. The cross-sectional shape of the protruding portion 2002 can also be a fan-shaped structure.

[0168] According to some embodiments of the present application, the embodiments of the present application also provide a battery 1000, including the battery cell 100 provided by any one of the above embodiments.

[0169] According to some embodiments of the present application, embodiments of the present application further provide an electrical device, including the battery 1000 provided in any of the above embodiments, and the battery 1000 is used to provide electrical energy.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, Comprising: A housing; An electrode assembly disposed within the housing, the electrode assembly including wound electrode tabs; Wherein, the electrode tab includes a first body section and a second body section connected along the winding direction, the second body section surrounding the first body section, and the first body section is provided with a concavo-convex structure.

2. The battery cell according to claim 1, characterized in that, The concavo-convex structure includes a convex portion and a concave portion, the convex portion protruding from one side of the first body section along the thickness direction of the electrode tab, the concave portion being recessed relative to the other side of the first body section along the thickness direction, and the position of the convex portion corresponding to the position of the concave portion.

3. The battery cell according to claim 1 or 2, characterized in that, The electrode tab is wound N turns from the inside out along the winding direction, the first body section starting from the 1st turn and extending to the Mth turn, where 2 ≤ M ≤ N.

4. The battery cell according to claim 3, wherein Along the winding direction, the concavo-convex structures provided on the first body sections of adjacent two turns are engaged and matched with each other.

5. The battery cell according to any one of claims 1 to 4, characterized in that, The thickness dimension d of the first body section and the maximum height dimension h of the concavo-convex structure in the thickness direction of the electrode tab satisfy the relationship: 1 / 600 ≤ d / h ≤ 3 / 100.

6. The battery cell according to claim 5, characterized in that The maximum height dimension h satisfies the relationship: 0.5 mm ≤ h ≤ 3 mm.

7. The battery cell according to claim 5 or 6, characterized in that, The first body section 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.

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

9. The battery cell according to any one of claims 1 to 8, characterized in that, The concavo-convex structure is a strip structure, and the concavo-convex structure extends along at least one of the axial direction and the winding direction of the electrode assembly.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The orthographic projection of the concavo-convex structure in the winding direction is any one of a polygon structure and a sector structure; or, the orthographic projection of the concavo-convex structure in the axial direction of the electrode assembly is any one of a polygon structure and a sector structure.

11. The battery cell according to any one of claims 1 to 10, characterized in that, The number of the concavo-convex structures is set to be multiple.

12. The battery cell according to claim 11, wherein, The multiple concavo-convex structures are spaced apart along the winding direction, and / or the multiple concavo-convex structures are spaced apart along the axial direction of the electrode assembly.

13. The battery cell according to claim 11, characterized in that, In the axial direction of the electrode assembly, the length dimension of the concavo-convex structure is the same as the length dimension of the first body section.

14. An electrode assembly, characterized in that, Including a wound electrode tab, the electrode tab includes a first body section and a second body section connected along the winding direction, the second body section surrounding the first body section, and the first body section is provided with a concavo-convex structure.

15. A winding needle is used to form an electrode assembly, the electrode assembly includes a wound electrode tab, and the electrode tab is provided with a concavo-convex structure, and is characterized in that, The winding needle includes: A winding body configured to wind the electrode tab; A protruding portion protruding from the outer peripheral surface of the winding body, the protruding portion being configured to push against the electrode tab to form the concavo-convex structure.

16. A battery, characterized in that, Including the battery cell according to any one of claims 1 to 13.

17. An electrical device, characterized in that, Including the battery according to claim 16, the battery being used to provide electrical energy.

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