Winding pin structure, winding device, and battery cell

Abstract

The present application provides a winding pin structure, a winding device, and a battery cell. The winding pin structure is used for forming an electrode assembly, and comprises a support pin body and a winding pin body. The support pin body has an annular structure and has a cavity formed in the axial direction of the support pin body. The winding pin body is inserted into the cavity and is detachably connected to the support pin body; one end of the winding pin body in the axial direction is configured to be connected to a driving mechanism, so as to drive the support pin body to rotate synchronously. Regarding the electrode assembly formed by winding of the winding pin structure provided by embodiments of the present application, the support pin body can automatically be arranged in a central winding hole of the electrode assembly and is used as part of the electrode assembly, thereby improving the quality and service life of the electrode assembly, and improving the quality and service life of the battery cell.

Description

Rolling needle structure, rolling device and battery cell

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202421982535.9, filed on August 15, 2024, entitled “Rolling needle structure, rolling device and battery cell”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application belongs to the technical field of battery manufacturing, and particularly relates to a rolling needle structure, a rolling device and a battery cell. BACKGROUND

[0004] With the development of new energy technology, batteries are increasingly widely used, for example, in mobile phones, notebook computers, electric vehicles, electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools.

[0005] The development of battery technology needs to consider various design factors, for example, a battery cell formed by rolling, which is prone to center hole collapse due to insufficient support at the center hole, affecting the quality and service life of the battery cell. SUMMARY

[0006] In view of the above problems, the present application provides a rolling needle structure, a rolling device and a battery cell, whereby the electrode assembly formed by the rolling needle structure can automatically set the support needle body in the rolling center hole of the electrode assembly and serve as part of the electrode assembly, thereby improving the quality and service life of the electrode assembly and thus improving the quality and service life of the battery cell.

[0007] In a first aspect, the present application provides a rolling needle structure for forming an electrode assembly, the rolling needle structure comprising: a support needle body in a ring structure and having a cavity arranged along the axial direction thereof; a rolling needle body inserted into the cavity and detachably connected with the support needle body, one end of the rolling needle body along the axial direction being configured to be connected with a driving mechanism to drive the support needle body to rotate synchronously.

[0008] In some embodiments of the first aspect, the winding needle structure comprises a detachably connected support needle body and a winding needle body, the winding needle body is inserted into the cavity of the support needle body, the winding needle body can be driven by the driving mechanism to drive the support needle body to rotate synchronously, the support needle body can drive the separator membrane or the pole piece to rotate so that the separator membrane and the pole piece are wound on the outer circumferential surface of the support needle body, after the preparation of the electrode assembly is completed, the winding needle body is removed, and the support needle body is left at the winding center hole of the electrode assembly, the support needle body can support the winding center hole to improve the problem of collapse of the winding center hole, thereby improving the quality and service life of the electrode assembly, and improving the quality and service life of the battery, and the support needle body is arranged at the winding center hole of the electrode assembly in this way, which is convenient to operate and conducive to automatic design.

[0009] In some embodiments, the inner circumferential surface of the support needle body is provided with a first matching part, and the outer circumferential surface of the winding needle body is provided with a second matching part, the first matching part and the second matching part are in contact and detachable connection. In this way, the connection strength of the support needle body and the winding needle body is improved.

[0010] In some embodiments, one of the first matching part and the second matching part is provided as a recess, and the other is provided as a protrusion, the protrusion and the recess are matched in shape and are in clamping connection. The support needle body and the winding needle body can be detachably connected by clamping, which is convenient to install and disassemble, and improves the operation efficiency.

[0011] In some embodiments, the recess comprises a groove formed by recessing from the inner circumferential surface to the outer circumferential surface of the support needle body, or the recess comprises a hole through the wall of the support needle body. In this way, the diversity of the winding needle structure is improved.

[0012] In some embodiments, the protrusion comprises an elastic member, which can be elongated or shortened in the radial direction of the annular structure. In this way, the assembly and disassembly between the winding needle body and the support needle body are facilitated.

[0013] In some embodiments, the first matching part comprises an inner thread arranged on the inner circumferential surface, and the second matching part comprises an outer thread arranged on the outer circumferential surface. The support needle body and the winding needle body can also be detachably connected by thread connection.

[0014] In some embodiments, the support needle body comprises two or more sub-support bodies distributed along the circumferential direction of the support needle body, the two or more sub-support bodies form a cavity, and at least one sub-support body is detachably connected with the winding needle body. The two sub-support bodies can clamp the separator membrane or the pole piece to wind it on the outer circumferential surface of the support needle body, which improves the connection strength of the support needle body and the separator membrane or the pole piece, and is convenient to operate.

[0015] In some embodiments, the winding needle body is coaxially arranged with the supporting needle body; or, the winding needle body has a fan-shaped structure in the axial projection, the winding needle body has an arc surface and a connecting surface arranged in connection, and the winding needle body is connected with the at least one sub-supporting body through the arc surface. By the above arrangement, the diversity of the winding needle structure is improved.

[0016] In some embodiments, the diameter of the cavity is greater than or equal to 5 mm and less than or equal to 30 mm. By arranging the diameter of the cavity within the above range, the cavity has sufficient space to insert the winding needle body.

[0017] In some embodiments, the diameter of the cavity is greater than or equal to 7 mm and less than or equal to 15 mm. By arranging the diameter of the cavity within the above range, the energy density of the battery cell is improved while the winding needle body is inserted.

[0018] In some embodiments, in the axial direction, the ratio of the length dimension of the part of the cavity into which the winding needle body is inserted to the length dimension of the supporting needle body is greater than or equal to 0.1 and less than or equal to 1. By the above arrangement, the effectiveness of the winding needle body driving the supporting needle body to rotate synchronously is ensured.

[0019] In some embodiments, the winding needle bodies are arranged in pairs, the supporting needle body has a first opening and a second opening communicating with the cavity along the two sides in the axial direction, one of the winding needle bodies arranged in pairs is inserted into the cavity through the first opening, and the other is inserted into the cavity through the second opening. By the above arrangement, the stability of the supporting needle body rotating with the winding needle body is improved.

[0020] In some embodiments, the wall portion of the supporting needle body has a through-flow hole arranged therein, and the through-flow hole communicates with the cavity. The arrangement of the through-flow hole can reduce the weight of the supporting needle body while reducing the influence of the supporting needle body on the electrode assembly during charging and discharging, so that the battery cell has more accommodation space for accommodating electrode reactants.

[0021] In a second aspect, the application provides a winding device, which comprises the winding needle structure provided in any of the embodiments of the first aspect, and a driving mechanism connected to one end of the winding needle body in the axial direction to drive the winding needle body to rotate.

[0022] In some embodiments of the second aspect, the winding device comprises a winding needle structure and a driving mechanism connected with the winding needle body and driving the winding needle body to rotate, the winding needle body drives the supporting needle body to rotate synchronously, so that the isolation film or the pole piece connected with the supporting needle body rotates, after the electrode assembly is prepared, the winding needle body is removed, and the supporting needle body is left at the winding center hole of the electrode assembly, the supporting needle body can support the winding center hole, so that the problem of the collapse of the winding center hole is improved. In this way, the supporting needle body is arranged at the center hole of the electrode assembly, which is convenient to operate and conducive to the realization of automatic design.

[0023] In some embodiments, the winding device further comprises an extraction mechanism, the extraction mechanism drives the winding needle body to move along the axial direction, so that the winding needle body is separated from the supporting needle body. By arranging the extraction mechanism, the winding needle body is removed conveniently, and automatic design is facilitated.

[0024] In a third aspect, the application provides a battery monomer, comprising: a shell; an electrode assembly arranged in the shell, the electrode assembly having a winding center hole; and the winding needle structure according to any one of the embodiments of the first aspect, the winding needle structure being arranged in the winding center hole.

[0025] The above description is only a summary of the technical solutions of the application. In order to more clearly understand the technical means of the application, the following specific embodiments of the application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments of the application. Obviously, the drawings described below are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0027] Fig. 1 is a structural schematic diagram of a supporting needle body according to some embodiments of the application;

[0028] Fig. 2 is an exploded structural schematic diagram of a supporting needle body according to some embodiments of the application;

[0029] Fig. 3 is a partial structural schematic diagram of a winding needle structure according to some embodiments of the application;

[0030] Fig. 4 is a structural schematic diagram of a supporting needle body according to some other embodiments of the application;

[0031] Fig. 5 is a structural schematic diagram of a winding needle body according to some embodiments of the application;

[0032] Fig. 6 is a partial sectional view of a battery monomer according to some embodiments of the application;

[0033] Fig. 7 is a partial cross-sectional view of a battery cell according to some embodiments of the present application;

[0034] Fig. 8 is a partial cross-sectional view of a battery cell according to some other embodiments of the present application;

[0035] Fig. 9 is a partial cross-sectional view of a battery cell according to some further embodiments of the present application.

[0036] In the drawings, the figures are not necessarily to scale as the illustrations are for clarity.

[0037] Label Description: 100-needle structure; 200-driving mechanism; 10-supporting needle body; 10a-cavity; 10b-first opening; 101-sub-supporting body; 11-wall part; 111-inner annular surface; 112-outer annular surface; 1111-recess; 1112-internal thread; 20-winding needle body; 21-protrusion; 22-external thread; 201-arc surface; 202-connection surface; 2-electrode assembly; 2a-winding center hole; 210-separating film; 220-pole piece; 221-first pole piece; 222-second pole piece; X-axial; Y-radial. DETAILED DESCRIPTION

[0038] The embodiments of the technical solutions of the present application will be described in detail below with reference to the 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.

[0039] 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 meaning understood by the skilled person in the field to which the embodiments of the present application belong.

[0040] In the description of the embodiments of the present application, the orientations or positional relationships indicated by the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated 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.

[0041] In addition, the technical terms "first", "second", and the like are only for description 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 "multiple" is two or more, unless otherwise specifically limited.

[0042] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, the terms "mount", "connect", "connect", "fix", and other terms should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or 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.

[0043] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0044] 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 hydropower, thermal power, wind power and solar power station, but also widely used in 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.

[0045] The development of battery technology should consider many design factors, for example, the battery monomer formed by winding, the central hole is prone to collapse due to insufficient support force, which affects the quality and service life of the battery monomer.

[0046] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery monomers to provide higher voltage and capacity. For example, the battery mentioned in the present application can include a battery module or a battery pack, etc.

[0047] The battery monomer can be a secondary battery monomer, which refers to a battery monomer that can be activated by charging after discharging to continue to use.

[0048] In some related technologies, the problem of the center hole collapse is solved by inserting a tube at the center hole of the finished electrode assembly, which is difficult to realize automatic production, and this way of inserting the tube after winding the electrode assembly will also affect the quality and flatness of the electrode tab or separator at the center hole, thereby affecting the quality and service life of the electrode assembly.

[0049] Based on the above technical problems, the embodiment of the present application provides a winding needle structure for forming an electrode assembly, the winding needle structure comprising: a support needle body in a ring structure and having a cavity arranged along the axial direction thereof; and a winding needle body inserted into the cavity and detachably connected with the support needle body, one end of the winding needle body along the axial direction being configured to be connected with a driving mechanism to drive the support needle body to rotate synchronously.

[0050] The winding needle structure comprises the detachably connected support needle body and winding needle body, the winding needle body is inserted into the cavity of the support needle body, the winding needle body can be driven by the driving mechanism to drive the support needle body to rotate synchronously, the support needle body can drive the separator or electrode tab to rotate, so that the separator and electrode tab are wound on the outer ring surface of the support needle body, after the electrode assembly is prepared, the winding needle body is removed, so that the support needle body remains at the winding center hole of the electrode assembly, the support needle body can support the winding center hole to improve the problem of the winding center hole collapse, which is beneficial to improve the quality and service life of the electrode assembly, thereby improving the quality and service life of the battery, and the support needle body is arranged at the winding center hole of the electrode assembly by this way, which is convenient to operate and beneficial to realize automatic design.

[0051] The winding needle structure provided by the embodiment of the present application can be produced and sold as an independent component, and of course, can also be used in a winding device as a component part of the winding device, which is beneficial to improve the quality and service life of the electrode assembly formed by the winding device, and also beneficial to realize automatic design, in addition, the winding needle structure can also be used in a battery monomer as a component part of the battery monomer, which is beneficial to improve the quality and service life of the battery monomer.

[0052] Please refer to FIGS. 1 to 9, according to the embodiment of the present application, a winding needle structure 100 is provided for forming an electrode assembly 2, the winding needle structure 100 comprising a support needle body 10 and a winding needle body 20. The support needle body 10 is in a ring structure and has a cavity 10a arranged along the axial direction X thereof. The winding needle body 20 is inserted into the cavity 10a and detachably connected with the support needle body 10, one end of the winding needle body 20 along the axial direction X being configured to be connected with a driving mechanism 200 to drive the support needle body 10 to rotate synchronously.

[0053] As shown in FIG. 1, the support needle body 10 includes a wall portion 11, which is annular in structure and encloses a cavity 10a, and has an inner annular surface 111 and an outer annular surface 112 opposite to each other along a radial direction Y of the support needle body 10.

[0054] As shown in FIGS. 6 and 7, the support needle body 10 is used to connect with the isolation film 210 or the pole piece 220 to drive them to rotate, so that the isolation film 210 and the pole piece 220 are wound on the outer annular surface 112 of the support needle body 10 to form the electrode assembly 2. The pole piece 220 can include a first pole piece 2201 and a second pole piece 2202.

[0055] It can be understood that the electrode assembly 2 wound and formed by the winding needle structure 100 provided by the embodiment of the present application includes the isolation film 210, the pole piece 220, and the support needle body 10, which is arranged at the winding center hole 2a of the electrode assembly 2 to provide a support function, prevent the collapse of the winding center hole 2a, and improve the quality and service life of the electrode assembly 2.

[0056] The support needle body 10 is annular in structure and has the cavity 10a arranged along an axial direction X thereof, so as to facilitate the insertion of the winding needle body 20 into the cavity 10a to connect with the support needle body 10, drive the support needle body 10 to rotate to wind the isolation film 210 and the pole piece 220, and enable the electrode assembly 2 after winding and forming to have the winding center hole 2a, i.e., the cavity 10a of the support needle body 10, to facilitate the circulation of the electrolyte in the electrode assembly 2.

[0057] The winding needle body 20 can be detachably connected with the support needle body 10. Specifically, when there is a need to prepare the electrode assembly 2, the winding needle body 20 can be inserted into the cavity 10a of the support needle body 10 and connected with the support needle body 10, one end of the winding needle body 20 along the axial direction X is connected with the driving mechanism 200, the isolation film 210 or the pole piece 220 is connected with the support needle body 10, the driving mechanism 200 is controlled to operate, so that the winding needle body 20 rotates and drives the support needle body 10 to rotate synchronously, the isolation film 210 and the pole piece 220 can be connected with the support needle body 10 and rotate with it to be wound to form the electrode assembly 2; after the electrode assembly 2 is wound and formed, the driving mechanism 200 is controlled to stop driving, and the winding needle body 20 is extracted to be separated from the support needle body 10, the support needle body 10 can be left in the winding center hole 2a of the electrode assembly 2 and serve as a part of the electrode assembly 2 to improve the support force of the winding center hole 2a.

[0058] The winding needle structure 100 provided by some embodiments of the present application includes a detachably connected support needle body 10 and a winding needle body 20. The winding needle body 20 is inserted into the cavity 10a of the support needle body 10. The winding needle body 20 can be driven by the driving mechanism 200 to drive the support needle body 10 to rotate synchronously. The support needle body 10 can drive the isolation film 210 or the pole piece 220 to rotate, so that the isolation film 210 and the pole piece 220 are wound on the outer circumferential surface 112 thereof. After the electrode assembly 2 is prepared, the winding needle body 20 is removed, so that the support needle body 10 remains in the winding central hole 2a of the electrode assembly 2. The support needle body 10 can support the winding central hole 2a, so as to improve the problem of collapse of the winding central hole 2a, and improve the quality and service life of the electrode assembly 2, thereby improving the quality and service life of the battery cell.

[0059] In addition, in this way, the support needle body 10 can be arranged in the winding central hole 2a of the electrode assembly 2 in advance, which is convenient to operate and conducive to automatic design, and does not damage the isolation film 210 or the pole piece 220, so as to ensure the flatness of the isolation film 210 or the pole piece 220, thereby ensuring the forming quality of the electrode assembly 2.

[0060] As shown in FIG. 3, in some embodiments, the orthogonal projection of the support needle body 10 on the axial direction X can be a circular ring structure. In this structure, the orthogonal projection of the winding needle body 20 on the axial direction X can include but is not limited to one of a circular structure and a semicircular structure, as long as the winding needle body 20 can be detachably connected with the support needle body 10.

[0061] For example, the orthogonal projection of the support needle body 10 on the axial direction X is a circular ring structure, and the orthogonal projection of the winding needle body 20 on the axial direction X is a circular structure, which is conducive to improving the connection area between the support needle body 10 and the winding needle body 20, thereby ensuring that the two can rotate synchronously.

[0062] As shown in FIG. 6, in some embodiments, the orthogonal projection of the support needle body 10 on the axial direction X can be a semicircular ring structure, and the number of support needle bodies 10 can be two, and the two support needle bodies 10 are connected with each other. In this structure, the orthogonal projection of the winding needle body 20 on the axial direction X can be a semicircular structure.

[0063] Optionally, the number of winding needle bodies 20 can be one, and the winding needle body 20 is detachably connected with one of the support needle bodies 10, so that the rotation of the winding needle body 20 can drive the two support needle bodies 10 to rotate synchronously.

[0064] Optionally, the number of winding needle bodies 20 can be two, and the winding needle body 20 is one-to-one connected with the support needle body 10.

[0065] In some embodiments, the support needle body 10 can be a one-piece structure; in some embodiments, the support needle body 10 can also include two half-ring structures and be formed by splicing the two half-ring structures. In some embodiments, the support needle body 10 can also include two or more fan-ring structures and be formed by splicing the two or more fan-ring structures.

[0066] Since the support needle body 10 does not need to be pulled out but remains in the winding center hole 2a of the electrode assembly 2, the cross-sectional shape of the support needle body 10 is determined according to the shape of the electrode assembly 2. In some embodiments, the orthographic projection of the support needle body 10 on the axial X can be a circular ring, an elliptical ring, a triangular ring, or the like.

[0067] The winding needle body 20 can be made of stainless steel, which has a certain rigidity and is beneficial to ensure the rotation effect and prevent failure during rotation.

[0068] The support needle body 10 can be made of a material resistant to electrolyte corrosion. In the embodiments of the present application, the material of the support needle body 10 is adapted to the material of the separation film 210, and both are PP composite materials. Alternatively, the support needle body 10 can also be made of other materials, such as polyethylene (PE), polyethylene terephthalate (PET), or other film materials, which have a certain supporting effect and are also beneficial to reduce the impact on the weight of the electrode assembly 2.

[0069] In some embodiments, the winding needle body 20 can be provided as a solid structure, which is beneficial to improve the strength of the winding needle body 20 and ensure the reliability and stability during rotation.

[0070] Alternatively, the winding needle body 20 can be detachably connected with the inner ring surface 111 of the support needle body 10, or the winding needle body 20 can also be detachably connected with the end of the support needle body 10 on either side of the axial X.

[0071] For example, a first connecting portion can be provided at one end of the support needle body 10 along the axial X, and a second connecting portion can be provided at one end of the winding needle body 20 along the axial X. The first connecting portion and the second connecting portion are detachably connected, that is, the support needle body 10 and the winding needle body 20 can be detachably connected at the ends thereof along the axial X, which is convenient for assembly and disassembly. For example, the first connecting portion and the second connecting portion can be connected by clamping or through the connection of fasteners such as bolts.

[0072] In some embodiments, the inner ring surface 111 of the support needle body 10 is provided with a first matching portion, and the outer peripheral surface of the winding needle body 20 is provided with a second matching portion. The first matching portion and the second matching portion are in contact and detachable connection.

[0073] By machining the first matching part on the inner annular surface 111 of the supporting needle body 10 and machining the second matching part on the outer annular surface 112 of the winding needle body 20, the two are detachably connected through the contact matching of the first matching part and the second matching part. By this way, the area of the connection between the supporting needle body 10 and the winding needle body 20 is increased, which is beneficial to improve the connection strength between the two, so as to ensure the rotation effect of the synchronous rotation of the two, and further improve the reliability of the winding needle structure 100.

[0074] Optionally, the part of the winding needle body 20 inserted into the cavity 10a can be provided with a second matching part, and the supporting needle body 10 is provided with a first matching part with the same area as the second matching part. Of course, all of the winding needle body 20 inserted into the cavity 10a can be provided with a second matching part.

[0075] Optionally, one of the first matching part and the second matching part can be provided as a recess 1111, and the other is provided as a protrusion 21, and the first matching part and the second matching part are detachably connected by clamping; or the first matching part and the second matching part can be provided as a threaded structure capable of being screwed together, and the first matching part and the second matching part are detachably connected by threaded connection; or at least one of the first matching part and the second matching part can be provided as a magnetic material body, and the first matching part and the second matching part are detachably connected by magnetic force.

[0076] Please refer to FIG. 3, in some embodiments, one of the first matching part and the second matching part is provided as a recess 1111, and the other is provided as a protrusion 21, the protrusion 21 and the recess 1111 are matched in shape and clamped together.

[0077] The number of protrusions 21 and grooves is the same, and the number of protrusions 21 and grooves can be set to two, three, or even more.

[0078] Optionally, the first matching part is a protrusion 21 provided on the inner annular surface 111 of the supporting needle body 10, and the second matching part is a recess 1111 provided on the outer peripheral surface of the winding needle body 20; or the first matching part is a recess 1111 provided on the inner annular surface 111 of the supporting needle body 10, and the second matching part is a protrusion 21 provided on the outer peripheral surface of the winding needle body 20.

[0079] The extension direction of the protrusion 21 is the same as the extension direction of the recess 1111, which facilitates the protrusion 21 to extend into the recess 1111 to clamp them together.

[0080] Exemplarily, the protrusion 21 can be a structure protruding from the inner annular surface 111 of the support needle body 10 towards the outer annular surface 112, and the recess 1111 can be a structure recessed from the outer peripheral surface of the winding needle body 20 towards the inside thereof; or, the protrusion 21 can be a structure protruding from the outer peripheral surface of the winding needle body 20 towards the inside thereof, and the recess 1111 can be a structure recessed from the inner annular surface 111 of the support needle body 10 towards the outer annular surface 112.

[0081] The winding needle structure 100 provided by some embodiments of the present application can realize detachable connection of the support needle body 10 and the winding needle body 20 through clamping, facilitating installation and disassembly, and being beneficial to improving operation efficiency.

[0082] In some embodiments, the recess 1111 includes a groove recessed from the inner annular surface 111 to the outer annular surface 112 of the support needle body 10.

[0083] The groove refers to a structure recessed from the inner annular surface 111 to the outer annular surface 112 of the support needle body 10 but not penetrating the wall 11 of the support needle body 10.

[0084] The first matching part can be a groove provided on the inner annular surface 111 of the support needle body 10, and the second matching part can be the protrusion 21 provided on the outer peripheral surface of the winding needle body 20. In this way, the machining and assembly are facilitated, the structural strength of the winding needle body 20 is facilitated to be ensured, the winding needle body 20 has sufficient rotation effect, and the weight of the support needle body 10 and the electrode assembly 2 including the support needle body 10 is reduced.

[0085] In some embodiments, the recess 1111 includes a hole penetrating the wall 11 of the support needle body 10.

[0086] The hole refers to a structure recessed from the inner annular surface 111 to the outer annular surface 112 of the support needle body 10 and penetrating the wall 11. In this way, when the winding needle body 20 is extracted, the support needle body 10 has a hole, the hole can be used as a passage for electrolyte and gas flow of the electrode assembly 2, the electrolyte and gas can have more space for storage, the electrical performance of the battery monomer is facilitated to be improved, and the weight of the support needle body 10 is facilitated to be reduced.

[0087] The winding needle structure 100 provided by some embodiments of the present application can set the first matching part of the inner annular surface 111 of the support needle body 10 as the recess 1111, the recess 1111 can be set as a groove or a hole, and the diversity of the winding needle structure 100 is facilitated to be improved.

[0088] Optionally, the protrusion 21 can be movably connected to the winding needle body 20, that is, the protrusion 21 can be extended radially Y from the winding needle body 20 or retracted into the winding needle body 20 to meet the assembly and disassembly of the winding needle body 20 and the support needle body 10.

[0089] In some embodiments, the protrusion 21 comprises an elastic member capable of being elongated or shortened along the radial direction Y of the annular structure.

[0090] The elastic member can refer to a structure having elasticity and capable of being elastically deformed, for example, the elastic member can comprise silica gel, rubber, etc.

[0091] When the winding needle body 20 is inserted into the cavity 10a along the axial direction X, the elastic member can be deformed by being extruded by the inner annular surface 111 of the supporting needle body 10, that is, the elastic member can be shortened along the radial direction Y, so as to enable the winding needle body 20 to continue to move along the axial direction X to be inserted into the cavity 10a; when the winding needle body 20 moves to the corresponding position, the elastic member restores the initial shape and is inserted into the recess 1111, that is, the elastic member can be elongated along the radial direction Y, at this time, the winding needle body 20 cannot continue to move along the axial direction X, so that the winding needle body 20 is connected to the supporting needle body 10; after the electrode assembly 2 is prepared, the winding needle body 20 is extracted along the axial direction X, at this time, the elastic member is deformed to leave the recess 1111.

[0092] For example, the inner annular surface 111 of the supporting needle body 10 has a circular ring structure in the axial direction X, the winding needle body 20 has a circular structure in the axial direction X and is coaxially arranged with the supporting needle body 10, the inner annular surface 111 of the supporting needle body 10 is provided with one of the protrusion 21 or the recess 1111, the outer peripheral surface of the winding needle body 20 is provided with the other one of the protrusion 21 or the recess 1111, and the protrusion 21 comprises an elastic member.

[0093] The winding needle structure 100 provided by some embodiments of the present application is arranged in the above manner, and can realize the clamping or separation with the recess 1111 by only providing an axial X force capable of deforming the elastic member, thereby facilitating the assembly and disassembly of the winding needle body 20 and the supporting needle body 10, and being simple to operate and conducive to improving the operation efficiency.

[0094] Please refer to FIG. 4 and FIG. 5, in some embodiments, the first matching part comprises an inner thread 1112 arranged on the inner annular surface 111, and the second matching part comprises an outer thread 22 arranged on the outer peripheral surface.

[0095] The inner thread 1112 refers to a structure having a spiral line shape machined on the inner annular surface 111 of the supporting needle body 10, the outer thread 22 refers to a structure having a spiral line shape machined on the outer peripheral surface of the winding needle body 20, and the threaded connection refers to a connection mode in which the supporting needle body and the winding needle body 20 are screwed to make the inner thread 1112 and the outer thread 22 match.

[0096] The winding needle structure 100 provided by some embodiments of the present application can realize detachable connection of the supporting needle body and the winding needle body 20 through threaded connection, facilitating assembly and disassembly, improving operation efficiency, and facilitating to ensure the sealing requirement after the connection of the two, so that particles such as dust and impurities from the outside cannot enter the supporting needle body 10, to cause pollution to the pole piece 220 or the isolation film 210, thereby facilitating to ensure the quality of the electrode assembly 2 after preparation and molding. In addition, the connection of the supporting needle body 10 and the winding needle body 20 can be made more firm, the noise influence during synchronous rotation is reduced, and the connection stability during rotation between the two is ensured.

[0097] For example, the inner annular surface 111 of the supporting needle body 10 has a circular ring structure in the axial X projection, the winding needle body 20 has a circular structure in the axial X projection and is coaxially arranged with the supporting needle body 10, the inner annular surface 111 of the supporting needle body 10 is provided with an inner thread 1112, the outer circumferential surface of the winding needle body 20 is provided with an outer thread 22, and the inner thread 1112 and the outer thread 22 are matched with each other to be screwed.

[0098] In an alternative embodiment, the supporting needle body 10 is an integral molding structure, and the starting end of the isolation film 210 is attached to the outer annular surface 112 of the supporting needle body 10, so as to completely cover the supporting needle body 10, so that there is at least one layer of isolation film 210 between the supporting needle body 10 and the pole piece 220.

[0099] As shown in FIGS. 2, 8 and 9, in some embodiments, the supporting needle body 10 includes two or more sub-supporting bodies 101 distributed along the circumferential direction of the supporting needle body 10, and the two or more sub-supporting bodies 101 form a cavity 10a, and at least one sub-supporting body 101 is detachably connected with the winding needle body 20.

[0100] The number of sub-supporting bodies 101 can be two or three, or more. In the above manner, the starting end of the isolation film 210 or the pole piece 220 can be pre-positioned between two adjacent sub-supporting bodies 101, and then wound around the outer periphery, facilitating installation and positioning, and facilitating to improve the connection strength of the isolation film 210 or the pole piece 220 and the supporting needle body 10, so that the supporting body can better drive the isolation film 210 or the pole piece 220 to rotate.

[0101] In some embodiments, each sub-supporting body 101 is detachably connected with the winding needle body 20.

[0102] As shown in FIG. 8, the number of sub-supporting bodies 101 is set to two, each of which is detachably connected with the winding needle body 20, and two abutting portions are formed between the two sub-supporting bodies 101. The starting end of the isolation film 210 can be pre-clamped in one of the abutting portions and attached to the outer periphery of the winding needle body 20, and then extended from the other abutting portion, so that the two sub-supporting bodies 101 can clamp the isolation film 210, facilitating the rotation of the isolation film 210. After the isolation film 210 is wound for a predetermined number of turns, the pole piece 220 can be fed and wound together with the isolation film 210 on the outer ring surface 112 of the supporting needle body 10.

[0103] In some embodiments, the winding needle body 20 is detachably connected with one of the sub-supporting bodies 101, and two or more sub-supporting bodies 101 are detachably connected with each other.

[0104] As shown in FIG. 9, the number of sub-supporting bodies 101 is set to two, and the two sub-supporting bodies 101 form a cavity 10a. The winding needle body 20 is detachably connected with one of the sub-supporting bodies 101, and the two sub-supporting bodies 101 are detachably connected with each other, so that the rotation of the winding needle body 20 can drive the synchronous rotation of all the sub-supporting bodies 101.

[0105] Among them, two or more sub-supporting bodies 101 can be connected by clamping, bonding or other means.

[0106] It can be understood that, since the isolation film 210 or the pole piece 220 is very thin, the adjacent two sub-supporting bodies 101 can pass through the isolation film 210 or the pole piece 220 located therebetween during assembly, so as to complete the assembly without affecting the overall quality of the electrode assembly 2.

[0107] In some embodiments, the winding needle body 20 is coaxially arranged with the supporting needle body 10.

[0108] By coaxially arranging the winding needle body 20 with the supporting needle body 10, the supporting needle body 10 can rotate around the same axis as the winding needle body 20, which is beneficial to improve the stability of the supporting needle body 10 rotating with the winding needle body 20, thereby improving the stability and uniformity of the isolation film 210 wound on the supporting needle body 10, and improving the quality of the wound electrode assembly 2.

[0109] For example, the supporting needle body 10 includes two sub-supporting bodies 101 distributed along the circumference thereof, the winding needle body 20 has the same shape as the cavity 10a of the supporting needle body 10 and is coaxially arranged, and the winding needle body 20 can be clamped and connected with each sub-supporting body 101.

[0110] In some embodiments, the inner annular surface 111 of the support needle body 10 has a positive projection in the axial direction X in a polygonal ring structure, the outer annular surface 112 of the support needle body 10 has a positive projection in the axial direction X in a circular ring structure, and the winding needle body 20 has a positive projection in the axial direction X in a polygonal structure and is coaxially arranged with the support needle body 10.

[0111] The polygonal ring structure can include, but is not limited to, a triangular ring structure, a rectangular ring structure, and the polygonal structure can include, but is not limited to, a triangular structure, a rectangular structure.

[0112] In some embodiments, the inner annular surface 111 of the support needle body 10 has a positive projection in the axial direction X in an elliptical ring structure, the outer annular surface 112 of the support needle body 10 has a positive projection in the axial direction X in a circular ring structure, and the winding needle body 20 has a positive projection in the axial direction X in an elliptical structure and is coaxially arranged with the support needle body 10.

[0113] As shown in FIG. 9, in some embodiments, the winding needle body 20 has a positive projection in the axial direction X in a fan-shaped structure, the winding needle body 20 has an arc surface 201 and a connecting surface 202 arranged in connection, and the winding needle body 20 is connected to at least one sub-support body 101 through the arc surface 201.

[0114] When the inner annular surface 111 of each sub-support body 101 has a positive projection in the axial direction X in an arc structure, the winding needle body 20 can be arranged in a fan-shaped structure and is arranged in detachable connection with the inner annular surface 111 of each sub-support body 101 through the arc surface 201, and a gap can be formed between the connecting surface 202 of the winding needle body 20 and each sub-support body 101.

[0115] In some embodiments, the winding needle body 20 is connected to one of the sub-support bodies 101 through the arc surface 201, and the adjacent two sub-support bodies 101 are connected to each other, so that the winding needle body 20 can drive each sub-support body 101 to rotate synchronously.

[0116] In some embodiments, the winding needle body 20 is arranged in connection with each sub-support body 101, that is, the arc surface 201 of the winding needle body 20 can be located at the abutting position of the adjacent two sub-support bodies 101, so that the winding needle body 20 can drive each sub-support body 101 to rotate synchronously.

[0117] By the above arrangement, the diversity of the winding needle structure 100 can be improved.

[0118] In some embodiments, the diameter of the cavity 10a is greater than or equal to 5 mm and less than or equal to 30 mm.

[0119] The diameter of the cavity 10a can be understood as the radial dimension of the inner annular surface 111.

[0120] For example, the diameter of the cavity 10a can be, but is not limited to, 5 mm, 7 mm, 10 mm, 13 mm, 15 mm, 17 mm, 20 mm, 22 mm, 25 mm, 27 mm, 30 mm, etc.

[0121] It can be understood that the smaller the diameter of the cavity 10a, i.e. greater than 5 mm, is not conducive to the insertion of the winding needle 20 in the cavity 10a; and the larger the diameter of the cavity 10a, i.e. less than 30 mm, will make the center hole occupy a larger space, thereby reducing the energy density of the battery cell.

[0122] Therefore, by setting the diameter of the cavity 10a to be between 5 mm and 30 mm, and including the two end values of 5 mm and 30 mm, the cavity 10a has sufficient space to be equipped with the winding needle 20, which facilitates the processing of the support needle 10 into a structure that can be detachably connected with the winding needle 20.

[0123] In some embodiments, the diameter of the cavity 10a is greater than or equal to 7 mm and less than or equal to 15 mm.

[0124] For example, the diameter of the cavity 10a can be, but is not limited to, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, etc.

[0125] By further setting the diameter of the cavity 10a to be between 7 mm and 15 mm, and including the two end values of 7 mm and 15 mm, the balance of facilitating the detachable connection of the support cavity 10a with the winding needle 20 and reducing the impact on the energy density of the battery cell can be better satisfied, that is, by this way of setting, while satisfying the insertion of the winding needle 20, it is beneficial to improve the energy density of the battery cell.

[0126] In some embodiments, the diameter of the cavity 10a is greater than or equal to 7 mm and less than or equal to 10 mm.

[0127] In some embodiments, in the axial direction X, the ratio of the length dimension of the portion of the winding needle 20 inserted into the cavity 10a to the length dimension of the support needle 10 is greater than or equal to 0.1 and less than or equal to 1.

[0128] In some embodiments, the number of winding needles 20 is one, and the winding needle 20 has a first winding portion and a second winding portion connected in the axial direction X, the first winding portion is inserted into the cavity 10a, and the ratio of the length dimension of the first winding portion to the length dimension of the support needle 10 in the axial direction X is greater than or equal to 0.1 and less than or equal to 1.

[0129] By the above way of setting, it is beneficial to ensure the effectiveness of the winding needle 20 in driving the support needle 10 to rotate synchronously.

[0130] In some embodiments, the ratio of the length dimension of the first winding portion to the length dimension of the support needle body 10 is greater than or equal to 0.5 and less than or equal to 0.8.

[0131] In some embodiments, the ratio of the length dimension of the first winding portion to the length dimension of the support needle body 10 is greater than or equal to 0.6 and less than or equal to 0.8.

[0132] In some embodiments, the ratio of the length dimension of the first winding portion to the length dimension of the support needle body 10 is greater than or equal to 0.7 and less than or equal to 0.8.

[0133] In some embodiments, the number of winding needle bodies 20 can be set to one, and correspondingly, the driving mechanism 200 is also set to one. The support needle body 10 has at least one opening in communication with the cavity 10a in the axial direction X, and the winding needle body 20 can be inserted into the cavity 10a through the opening to be detachably connected with the support needle body 10.

[0134] As shown in FIG. 4, in some embodiments, the winding needle bodies 20 are arranged in pairs. The support needle body 10 has a first opening 10b and a second opening in communication with the cavity 10a on both sides in the axial direction X. One of the winding needle bodies 20 arranged in pairs is inserted into the cavity 10a through the first opening 10b, and the other is inserted into the cavity 10a through the second opening.

[0135] The number of winding needle bodies 20 can be set to two, and correspondingly, the driving mechanism 200 is also set to two. The support needle body 10 has a first opening 10b and a second opening in communication with the cavity 10a at both ends in the axial direction X. One of the winding needle bodies 20 is inserted into the cavity 10a through the first opening 10b to be detachably connected with the support needle body 10, and the other is inserted into the cavity 10a through the second opening to be detachably connected with the support needle body 10. The two driving mechanisms 200 simultaneously drive the two winding needle bodies 20 to rotate, so that the support needle body 10 rotates synchronously.

[0136] The winding needle structure 100 provided by some embodiments of the present application is arranged in the above manner, which is beneficial to improve the stability of the support needle body 10 rotating with the winding needle body 20.

[0137] In some embodiments, the number of winding needle bodies 20 is set to two. The winding needle body 20 has a first winding portion and a second winding portion connected in the axial direction X. The two first winding portions are inserted into the cavity 10a. In the axial direction X, the ratio of the sum of the length dimensions of the two first winding portions to the length dimension of the support needle body 10 is greater than or equal to 0.1 and less than or equal to 1.

[0138] Each winding needle body 20 has a first winding part and a second winding part connected in the axial direction X, the first winding part is inserted into the cavity 10a, and the length of each first winding part in the axial direction X is greater than or equal to 0.1 times and less than or equal to 0.5 times the length of the support needle body 10.

[0139] In some embodiments, the wall part 11 of the support needle body 10 has a flow guide hole penetratingly arranged and communicating with the cavity 10a.

[0140] The flow guide hole is used for the electrolyte and gas to pass through. Optionally, the number of flow guide holes can be one, two, or multiple. The arrangement of the flow guide hole can reduce the weight of the support needle body 10 and the influence of the support needle body 10 on the electrode assembly 2 during charging and discharging, so that the battery cell has more space for accommodating electrode reaction substances.

[0141] Optionally, at least part of the plurality of flow guide holes can be spaced apart in the axial direction X of the support needle body 10, and at least part of the plurality of flow guide holes can be spaced apart in the circumferential direction of the support needle body 10 to ensure uniform flow of the electrolyte.

[0142] The embodiment of the present application also provides a winding device, which comprises the winding needle structure 100 provided by any of the above embodiments and a driving mechanism 200 connected to one end of the winding needle body 20 in the axial direction X to drive the winding needle body 20 to rotate.

[0143] The winding device provided by the embodiment of the present application can automatically arrange the support needle body 10 having a supporting effect in the winding center hole 2a of the electrode assembly 2. The electrode assembly 2 formed by the winding device provided by the embodiment of the present application has good forming quality, and the winding center hole 2a will not collapse, which is beneficial to improve the service life.

[0144] The winding device further comprises a mounting seat, the winding needle body 20 can be connected to the mounting seat through the driving mechanism 200, and the winding needle structure 100 can be detachably connected to the mounting seat.

[0145] In some optional embodiments, the winding needle body 20 is detachably connected to the mounting seat, which is convenient for maintenance or replacement of the winding needle body 20.

[0146] In some embodiments, the winding device further comprises an extraction mechanism, the extraction mechanism drives the winding needle body 20 to move in the axial direction X to separate the winding needle body 20 from the support needle body 10.

[0147] Optionally, the extraction mechanism can be connected to the mounting seat to drive the winding needle body 20 to move in the axial direction X to extract the winding needle body 20 from the cavity 10a of the support needle body 10.

[0148] Optionally, the extracting mechanism can comprise a cylinder assembly, which can comprise a cylinder and a connecting rod connected between the cylinder and the winding needle body 20, the cylinder drives the connecting rod to move eastward, thereby driving the winding needle body 20 and the mounting seat to move.

[0149] Please continue to refer to FIGS. 1-9, according to the winding needle structure 100 provided by the embodiments of the present application, the embodiments of the present application also provide a battery monomer, which comprises a shell, an electrode assembly 2 and the winding needle structure 100 provided by any of the above embodiments. The electrode assembly 2 has a winding center hole 2a, and the winding needle structure 100 is arranged in the winding center hole 2a.

[0150] The shell is a component for forming an internal environment of the battery monomer, which can be used to accommodate the electrode assembly 2, and can also be used to accommodate electrolyte and other components. Optionally, the shell can be made of, but is 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.

[0151] It can be understood that the winding needle structure 100 provided by the embodiments of the present application can be arranged in the winding center hole 2a of the electrode assembly 2, that is, after the electrode assembly 2 is manufactured by using the winding needle structure 100, the winding needle body 20 does not need to be removed, which is beneficial to improve the manufacturing efficiency.

[0152] As shown in FIG. 7, the number of the support needle body 10 can be set to two, and the orthographic projection of each support needle body 10 on the axial X presents a semi-circular ring structure, the orthographic projection of the winding needle body 20 on the axial X presents a fan-shaped structure, and the winding needle body 20 is arranged in and detachably connected with the cavity 10a of one of the support needle bodies 10. By this way of arrangement, after the electrode assembly 2 is prepared by using the winding needle structure 100, the winding needle body 20 does not need to be removed, which is beneficial to further improve the support effect on the winding center hole 2a of the electrode assembly 2, and is also beneficial to improve the operation efficiency. Moreover, since the winding needle body 20 is arranged in only one of the support needle bodies 10, it is also beneficial to ensure the flow of electrolyte.

[0153] As shown in FIG. 9, the winding needle body 20 comprises two sub-support bodies 101, the orthographic projection of the winding needle body 20 on the axial X presents a fan-shaped structure, and the winding needle body 20 is arranged in and detachably connected with one of the sub-support bodies 101. By this way of arrangement, after the electrode assembly 2 is prepared by using the winding needle structure 100, the winding needle body 20 does not need to be removed, which is beneficial to further improve the support effect on the winding center hole 2a of the electrode assembly 2, and is also beneficial to improve the operation efficiency. Moreover, since the winding needle body 20 is arranged in only one of the sub-support bodies 101, it is also beneficial to ensure the flow of electrolyte.

[0154] Of course, the support needle body 10 can also include three or even more sub-support bodies 101, and the number of the winding needle body 20 can be set to two, three or even more.

[0155] Of course, the support needle body 10 and the winding needle body 20 can also be provided in other structures other than the above-mentioned embodiments, which will not be described here.

[0156] The electrode assembly 2 includes a first electrode sheet 2201, a separator 210 and a second electrode sheet 2202 which are sequentially stacked in the winding direction.

[0157] For example, the separator 210 is arranged between the first electrode sheet 2201 and the second electrode sheet 2202, and the first electrode sheet 2201 is located inside the second electrode sheet 2202, and the second electrode sheet 2202 surrounds the first electrode sheet 2201. Therefore, the first electrode sheet 2201 is a positive electrode sheet, and the second electrode sheet 2202 is a negative electrode sheet, so as to avoid the phenomenon of metal precipitation in the charging and discharging process.

[0158] The needle winding structure 100 is arranged in the winding center hole 2a of the electrode assembly 2, specifically, the separator 210 extends out relative to the first electrode sheet 2201 in the winding direction and is stacked and wound with the support needle body 10.

[0159] The separator 210 can be connected with the outer ring surface 112 of the support needle body 10 and attached to the outer ring surface 112 of the support needle body 10, which is beneficial to fix the relative position and facilitate the support needle body 10 to drive the separator 210 to wind.

[0160] The needle winding structure 100 is located in the winding center hole 2a of the electrode assembly 2, which can provide a support stress from the inside of the battery monomer to the outside for the electrode assembly 2, thereby avoiding the first electrode sheet 2201 and the second electrode sheet 2202 from collapsing to the center in the charging and discharging process.

[0161] In an alternative embodiment, in the axial direction X, the length dimensions of the separator 210, the first electrode sheet 2201 and the second electrode sheet 2202 are equal, and the length dimension of the needle winding structure 100 is smaller than the length dimensions of the separator 210, the first electrode sheet 2201 and the second electrode sheet 2202, that is, the needle winding structure 100 can be arranged in the winding center hole 2a of the electrode assembly 2, and the length dimension in the axial direction X is not greater than the dimension in the height direction of the battery monomer, so as to be adapted to the shell of the battery monomer.

[0162] In another alternative embodiment, in the axial direction X, the length dimensions of the separator 210, the first electrode sheet 2201, the second electrode sheet 2202 and the needle winding structure 100 are equal, so that the needle winding structure 100 can better provide a support effect.

[0163] The battery cell provided by some embodiments of the present application is improved in quality and service life by arranging a winding needle structure 100 in the winding center hole 2a of the electrode assembly 2 to support the winding center hole 2a and improve the problem of collapse of the winding center hole 2a, thereby improving the quality and service life of the battery cell and the battery.

[0164] In addition, the winding needle body 20 in the winding needle structure 100 can be driven by the driving mechanism 200 to drive the supporting needle body 10 to rotate synchronously, and the supporting needle body 10 can drive the separator 210 or the pole piece 220 to rotate, so that the separator 210 and the pole piece 220 are wound on the outer ring surface 112 of the supporting needle body 10 to form the electrode assembly 2. The manufacturing process will not damage the separator 210 or the pole piece 220, thereby improving the flatness of the separator 210 or the pole piece 220, improving the forming quality of the electrode assembly 2, and further improving the forming quality of the battery cell.

[0165] In addition, the automatic design is facilitated, and the manufacturing efficiency of the electrode assembly 2 is improved, thereby improving the manufacturing efficiency of the battery cell.

[0166] The winding needle structure 100 provided by the embodiments of the present application is used to form the electrode assembly 2, and the winding needle structure 100 comprises a supporting needle body 10 and a winding needle body 20.

[0167] The supporting needle body 10 has a cavity 10a arranged along the axial direction X and is in a ring structure. The inner ring surface 111 of the supporting needle body 10 is provided with a first matching part and comprises two sub-supporting bodies 101 distributed along the circumferential direction. The two sub-supporting bodies 101 form the cavity 10a. The diameter of the cavity 10a is greater than or equal to 7 mm and less than or equal to 15 mm.

[0168] The winding needle body 20 is inserted into the cavity 10a. The outer circumferential surface of the winding needle body 20 is provided with a second matching part. The first matching part and the second matching part are in contact and detachable connection. One end of the winding needle body 20 along the axial direction X is configured to be connected with the driving mechanism 200 to drive the supporting needle body 10 to rotate synchronously. The first matching part is arranged as a hole body penetrating through the wall part 11 of the supporting needle body 10. The second matching part is arranged as a recess 1111. The hole body and the recess 1111 are in shape matching and clamping connection.

[0169] The winding needle body 20 is in a fan structure in the axial direction X and has an arc surface 201 and a connecting surface 202 arranged in connection. The winding needle body 20 is connected with one of the sub-supporting bodies 101 through the arc surface 201. The winding needle body 20 has a first winding part and a second winding part connected along the axial direction X. The first winding part is inserted into the cavity 10a. In the axial direction X, the ratio of the length of the first winding part to the length of the supporting needle body 10 is greater than or equal to 0.1 and less than or equal to 1.

[0170] 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 still be modified, or some or all of the technical features can be replaced equivalently. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. 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 winding needle structure for forming an electrode assembly, the winding needle structure comprising: a support needle body in a ring structure and having a cavity arranged along an axial direction of the support needle body; a winding needle body inserted into the cavity and detachably connected with the support needle body, an end of the winding needle body along the axial direction being configured to be connected with a driving mechanism to drive the support needle body to rotate synchronously.

2. The needle structure of claim 1, wherein, An inner ring surface of the support needle body is provided with a first matching part, and an outer peripheral surface of the winding needle body is provided with a second matching part, the first matching part and the second matching part being in contact and detachable connection.

3. The needle structure of claim 2, wherein, One of the first matching part and the second matching part is provided as a recess, and the other is provided as a protrusion, the protrusion being matched with the recess in shape and being in clamping connection.

4. The needle structure of claim 3, wherein, The recess comprises a groove formed by recessing from an inner ring surface to an outer ring surface of the support needle body, or the recess comprises a hole penetrating a wall of the support needle body.

5. The spool pin structure of claim 3 or 4, wherein, The protrusion comprises an elastic member capable of being elongated or shortened along a radial direction of the ring structure.

6. The needle structure of claim 2, wherein, The first matching part comprises an inner thread arranged on the inner ring surface, and the second matching part comprises an outer thread arranged on the outer peripheral surface.

7. The spool pin structure of any one of claims 1 to 5, wherein, The support needle body comprises two or more sub-support bodies distributed along a circumferential direction of the support needle body, the two or more sub-support bodies enclosing the cavity, and at least one of the sub-support bodies being detachably connected with the winding needle body.

8. The needle structure of claim 7, wherein, The winding needle body is coaxially arranged with the support needle body, or a normal projection of the winding needle body on the axial direction is in a fan structure, the winding needle body having an arc surface and a connecting surface arranged in connection, and the winding needle body being connected with at least one of the sub-support bodies through the arc surface.

9. The spool pin structure of any one of claims 1 to 8, wherein, A diameter of the cavity is greater than or equal to 5 mm and less than or equal to 30 mm.

10. The spool pin structure of any one of claims 1 to 8, wherein, The diameter of the cavity is greater than or equal to 7 mm and less than or equal to 15 mm.

11. The spool pin structure of any one of claims 1 to 10, wherein, In the axial direction, a ratio of a length dimension of a part of the cavity into which the winding needle body is inserted to a length dimension of the support needle body is greater than or equal to 0.1 and less than or equal to 1.

12. The spool pin structure of any one of claims 1 to 11, wherein, The winding needle bodies are arranged in pairs, the support needle body has a first opening and a second opening in communication with the cavity on two sides along the axial direction, one of the winding needle bodies arranged in pairs is inserted into the cavity through the first opening, and the other is inserted into the cavity through the second opening.

13. The spool pin structure of any one of claims 1 to 12, wherein, A wall of the support needle body has a flow guide hole arranged in penetration, the flow guide hole being in communication with the cavity. 14.A winding device, comprising: the winding needle structure according to any one of claims 1 to 13; a driving mechanism connected with an end of the winding needle body along the axial direction to drive the winding needle body to rotate.

15. The winding apparatus according to claim 14, wherein, The winding device further comprises an extraction mechanism, the extraction mechanism driving the winding needle body to move along the axial direction to separate the winding needle body from the support needle body. 16.A battery cell, comprising: a housing; an electrode assembly arranged in the housing, the electrode assembly having a winding center hole; the winding needle structure according to any one of claims 1 to 13, the winding needle structure being arranged in the winding center hole.

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