Winding needle structure, winding equipment and battery monomer

Abstract

The utility model provides a winding needle structure, winding equipment and a battery monomer, the winding needle structure is used for forming an electrode assembly, and the winding needle structure comprises a supporting needle body and a winding needle body. The supporting needle body is of an annular structure and is provided with a cavity formed in the axial direction of the supporting needle body. The winding needle body is inserted into the cavity and detachably connected with the supporting needle body, and one end of the winding needle body in the axial direction is configured to be connected with the driving mechanism so as to drive the supporting needle body to rotate synchronously. According to the electrode assembly formed by winding of the winding needle structure, the supporting needle body can be automatically arranged in the winding center hole of the electrode assembly and serves as a part of the electrode assembly, the quality of the electrode assembly can be improved, the service life of the electrode assembly can be prolonged, and therefore the quality of a single battery can be improved, and the service life of the single battery can be prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and in particular, to a winding needle structure, a winding device, and a battery cell. Background Art

[0002] With the development of new energy technologies, batteries are increasingly widely used, such as in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools.

[0003] The development of battery technologies needs to consider multiple design factors simultaneously. For example, in a battery cell formed by winding, due to insufficient support force at the central hole, the problem of central hole collapse is likely to occur, which affects both the quality and service life of the battery cell. Summary of the Utility Model

[0004] In view of the above problems, the present application provides a winding needle structure, a winding device, and a battery cell. The electrode assembly formed by winding with this winding needle structure can automatically set a support needle body at the winding central hole of the electrode assembly and use it as a part of the electrode assembly, which is beneficial to improving the quality and service life of the electrode assembly, and thus beneficial to improving the quality and service life of the battery cell.

[0005] In a first aspect, the present application provides a winding needle structure for forming an electrode assembly. The winding needle structure includes: a support needle body, which is in an annular structure and has a cavity arranged along its own axial direction; a winding needle body, which is inserted into the cavity and is detachably connected to the support needle body. One end of the winding needle body along the axial direction is configured to be connected to a driving mechanism to drive the support needle body to rotate synchronously.

[0006] In some embodiments of the first aspect, the winding needle structure includes a support needle body and a winding needle body that are detachably connected. The winding needle body is inserted into the cavity of the support needle body. The winding needle body can be driven by a driving mechanism to drive the support needle body to rotate synchronously. The support needle body can drive the separator or the electrode sheet to rotate, so that the separator and the electrode sheet are wound around its outer ring surface. When the electrode assembly is prepared, the winding needle body is removed, so that the support needle body remains at the winding central hole of the electrode assembly. The support needle body can support the winding central hole to improve the problem of winding central hole collapse, which is beneficial to improving the quality and service life of the electrode assembly, and thus beneficial to improving the quality and service life of the battery. Moreover, by setting the support needle body at the winding central hole of the electrode assembly in this way, the operation is convenient and beneficial to realizing an automated design.

[0007] In some embodiments, a first mating portion is provided on the inner circumferential surface of the support needle body, and a second mating portion is provided on the outer circumferential surface of the winding needle body. The first mating portion and the second mating portion are in contact and detachably connected. By setting it in this way, it is beneficial to improve the connection strength between the support needle body and the winding needle body.

[0008] In some embodiments, one of the first mating portion and the second mating portion is set as a concave portion, and the other is set as a convex portion. The shape of the convex portion matches that of the concave portion and they are snap-fitted. The support needle body and the winding needle body can be detachably connected by snap-fitting, which is convenient for installation and disassembly and beneficial to improving the operation efficiency.

[0009] In some embodiments, the concave portion includes a groove formed by recessing from the inner circumferential surface to the outer circumferential surface of the support needle body, or the concave portion includes a hole penetrating through the wall portion of the support needle body. By setting it in this way, it is beneficial to improve the diversity of the winding needle structure.

[0010] In some embodiments, the convex portion includes an elastic member, and the elastic member can extend or contract along the radial direction of the annular structure. By setting it in this way, it is convenient for the assembly and disassembly between the winding needle body and the support needle body.

[0011] In some embodiments, the first mating portion includes an internal thread provided on the inner circumferential surface, and the second mating portion includes an external thread provided on the outer circumferential surface. The support needle body and the winding needle body can also be detachably connected by means of a threaded connection.

[0012] In some embodiments, the support needle body includes two or more sub-support bodies distributed along its own circumference. The two or more sub-support bodies enclose a cavity, and at least one sub-support body is detachably connected to the winding needle body. An isolation film or a pole piece can be clamped between two sub-support bodies to wind it around the outer circumferential surface of the support needle body, which is beneficial to improving the connection strength between the support needle body and the isolation film or the pole piece and is convenient for operation.

[0013] In some embodiments, the winding needle body and the support needle body are coaxially arranged; or, the positive projection of the winding needle body in the axial direction is in a fan-shaped structure. The winding needle body has an arc surface and a connecting surface connected. The winding needle body is connected to at least one sub-support body through the arc surface. By setting it in the above manner, it is beneficial to improve the diversity of the winding needle structure.

[0014] 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 setting the diameter of the cavity within the above range, it is to ensure that the cavity has enough space to insert the winding needle body.

[0015] 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 setting the diameter of the cavity within the above range, while meeting the requirement of inserting the winding needle body, it is beneficial to improve the energy density of the battery cell.

[0016] In some embodiments, axially, the ratio of the length dimension of the portion of the winding needle body inserted into the cavity to the length dimension of the support needle body is greater than or equal to 0.1 and less than or equal to 1. By setting in the above manner, it is beneficial to ensure the effectiveness of the winding needle body to drive the support needle body to rotate synchronously.

[0017] In some embodiments, the winding needle bodies are arranged in pairs. Both sides of the support needle body along the axial direction have a first opening and a second opening communicating with the cavity. One of the pair of winding needle bodies is inserted into the cavity through the first opening, and the other is inserted into the cavity through the second opening. By setting in the above manner, it is beneficial to improve the stability of the support needle body rotating with the winding needle body.

[0018] In some embodiments, the wall of the support needle body has a diversion hole penetrating therethrough, and the diversion hole communicates with the cavity. The setting of the diversion hole can reduce the weight of the support needle body while reducing the influence of the support needle body on the electrode assembly during charge and discharge, so that there is more accommodation space for electrode reaction substances inside the battery cell.

[0019] In a second aspect, the present application provides a winding device, including the winding needle structure provided in any embodiment of the first aspect; a driving mechanism connected to one end of the winding needle body along the axial direction to drive the winding needle body to rotate.

[0020] In some embodiments of the second aspect, the winding device includes a winding needle structure and a driving mechanism. The driving mechanism is connected to the winding needle body and drives the winding needle body to rotate. The winding needle body drives the support needle body to rotate synchronously, so that the separator or the electrode sheet connected to the support needle body rotates. 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 collapse of the winding center hole. By setting the support needle body at the center hole of the electrode assembly in this way, the operation is convenient and it is beneficial to realize automatic design.

[0021] In some embodiments, the winding device further includes a drawing-out mechanism, and the drawing-out mechanism drives the winding needle body to move axially to separate the winding needle body from the support needle body. By providing the drawing-out mechanism, it is convenient to remove the winding needle body and it is beneficial to realize automatic design.

[0022] In a second aspect, the present application provides a battery cell, including: a housing; an electrode assembly disposed inside the housing, and the electrode assembly has a winding center hole; the winding needle structure provided in any embodiment of the first aspect, and the winding needle structure is disposed in the winding center hole.

[0023] The above description is only an overview of the technical solution of the present application. In order to understand the technical means of the present application more clearly, it can be implemented in accordance with 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 specific embodiments of the present application are specifically given. Description of the Drawings

[0024] 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:

[0025] Figure 1 is a schematic structural diagram of a support needle body provided in some embodiments of the present application;

[0026] Figure 2 is an exploded structural diagram of a support needle body provided in some embodiments of the present application;

[0027] Figure 3 is a partial structural diagram of a winding needle structure provided in some embodiments of the present application;

[0028] Figure 4 is a schematic structural diagram of a support needle body provided in some other embodiments of the present application;

[0029] Figure 5 is a schematic structural diagram of a winding needle body provided in some embodiments of the present application;

[0030] Figure 6 is a partial cross-sectional view of a battery cell provided in some embodiments of the present application;

[0031] Figure 7 is a partial cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0032] Figure 8 is a partial cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0033] Figure 9 is a partial cross-sectional view of a battery cell provided in some other embodiments of the present application.

[0034] The reference numerals in the specific embodiments are as follows:

[0035] 100 - winding needle structure; 200 - driving mechanism;

[0036] 10 - support needle body; 10a - cavity; 10b - first opening; 101 - sub - support body; 11 - wall portion; 111 - inner ring surface; 112 - outer ring surface; 1111 - recess; 1112 - internal thread;

[0037] 20 - Winding needle body; 21 - Protrusion; 22 - External thread; 201 - Arc surface; 202 - Connection surface;

[0038] 2 - Electrode assembly; 2a - Winding center hole; 210 - Separator film; 220 - Electrode tab; 221 - First electrode tab; 222 - Second electrode tab;

[0039] X - Axial direction; Y - Radial direction. Detailed implementation manners

[0040] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, so they are only examples and cannot be used to limit the protection scope of the present application.

[0041] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should be the ordinary meanings understood by those skilled in the art to which the embodiments of the present application belong.

[0042] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship 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 cannot be understood as a limitation to the embodiments of the present application.

[0043] In addition, the technical terms "first", "second", etc. are only used for descriptive purposes and cannot be understood 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 more than two, unless otherwise specifically defined.

[0044] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, the technical terms "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.

[0045] In the description of the embodiments of the present application, unless otherwise clearly defined 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 indirectly in 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 simply indicates that the horizontal height of the first feature is higher than that of 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 simply indicates that the horizontal height of the first feature is less than that of the second feature.

[0046] 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 applied to energy storage power systems such as hydraulic, thermal, wind and solar power stations, but also widely applied to electric transportation means such as electric bicycles, electric motorcycles, electric vehicles, as well as multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of batteries, the market demand for them is also constantly increasing.

[0047] The development of battery technology needs to consider various design factors at the same time. For example, for a battery cell formed by winding, due to insufficient supporting force at the central hole, the problem of central hole collapse is likely to occur, which affects both the quality and service life of the battery cell.

[0048] 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.

[0049] The battery cell can be a secondary battery cell, which refers to a battery cell that can activate the active material through charging after discharging.

[0050] In some related technologies, a tube body is inserted into the central hole of the fabricated electrode assembly to solve the problem of central hole collapse. This method is difficult to achieve automated production. Moreover, this method of winding the electrode assembly first and then inserting the tube body will also affect the quality and flatness of the electrode sheet or separator film at the central hole, thereby having a certain impact on the quality and service life of the electrode assembly.

[0051] Based on the above technical problems, the embodiments of the present application provide a winding needle structure for forming an electrode assembly. The winding needle structure includes: a support needle body, which is in an annular structure and has a cavity arranged along its own axial direction; a winding needle body, which is inserted into the cavity and is detachably connected to the support needle body. One end of the winding needle body along the axial direction is configured to be connected to a driving mechanism to drive the support needle body to rotate synchronously.

[0052] The winding needle structure includes a support needle body and a winding needle body that are detachably connected. The winding needle body is inserted into the cavity of the support needle body. The winding needle body can be driven by a driving mechanism to drive the support needle body to rotate synchronously. The support needle body can drive the separator or the electrode tab to rotate, so that the separator and the electrode tab are wound around its outer ring surface. After the electrode assembly is prepared, the winding needle body is removed, and 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 collapse of the winding center hole, which is beneficial to improving the quality and service life of the electrode assembly, and thus beneficial to improving the quality and service life of the battery. Moreover, by setting the support needle body at the winding center hole of the electrode assembly in this way, the operation is convenient and it is beneficial to realize the automated design.

[0053] The winding needle structure provided by the embodiment of the present application can be produced and sold as an independent component. Of course, it can also be used in a winding device and be a component in the winding device, which is beneficial to improving the quality and service life of the electrode assembly wound and formed by the winding device, and is also beneficial to realizing the automated design. In addition, it can also be used in a battery cell and be a component in the battery cell, which is beneficial to improving the quality and service life of the battery cell.

[0054] Please refer to Figures 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 includes a support needle body 10 and a winding needle body 20. The support needle body 10 has an annular structure and has a cavity 10a arranged along its own axial direction X. The winding needle body 20 is inserted into the cavity 10a and is detachably connected to the support needle body 10. One end of the winding needle body 20 along the axial direction X is configured to be connected to a driving mechanism 200 to drive the support needle body 10 to rotate synchronously.

[0055] Among them, as Figure 1 shown, the support needle body 10 includes a wall portion 11. The wall portion 11 has an annular structure and encloses to form the cavity 10a. The wall portion 11 has an inner ring surface 111 and an outer ring surface 112 that are opposite to each other along the radial direction Y of the support needle body 10.

[0056] As Figure 6 and Figure 7 shown, the support needle body 10 is used to be connected to the separator 210 or the electrode tab 220 to drive them to rotate together, so that the separator 210 and the electrode tab 220 are wound around the outer ring surface 112 of the support needle body 10 to form the electrode assembly 2. Among them, the electrode tab 220 may include a first electrode tab 2201 and a second electrode tab 2202.

[0057] It can be understood that the electrode assembly 2 wound and formed by the winding needle structure 100 provided by the embodiments of the present application includes a separator 210, a pole piece 220, and a support needle body 10. The support needle body 10 is disposed in the winding center hole 2a of the electrode assembly 2 to provide a support function, prevent the collapse problem of the winding center hole 2a, and improve the quality and service life of the electrode assembly 2.

[0058] The support needle body 10 has an annular structure and has a cavity 10a disposed along its own axial direction X, which facilitates the insertion of the winding needle body 20 into the cavity 10a to be connected to the support needle body 10, so as to drive the support needle body 10 to rotate to wind the separator 210 and the pole piece 220. Moreover, it can also enable the wound electrode assembly 2 to have a winding center hole 2a, where the winding center hole 2a is the cavity 10a of the support needle body 10, facilitating the circulation of the electrolyte in the electrode assembly 2.

[0059] The winding needle body 20 can be detachably connected to 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 to the support needle body 10. One end of the winding needle body 20 along the axial direction X is connected to the driving mechanism 200. The separator 210 or the pole piece 220 is connected to the support needle body 10, and 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 separator 210 and the pole piece 220 can be connected to the support needle body 10 and rotate therewith to wind and 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 withdrawn to be separated from the support needle body 10. The support needle body 10 can remain in the winding center hole 2a of the electrode assembly 2 and serve as a part of the electrode assembly 2 to improve the supporting force of the winding center hole 2a.

[0060] The winding needle structure 100 provided by some embodiments of the present application includes a support needle body 10 and a winding needle body 20 that are detachably connected. 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 separator 210 or the pole piece 220 to rotate, so that the separator 210 and the pole piece 220 are wound around its outer ring surface 112. 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 center hole 2a of the electrode assembly 2. The support needle body 10 can support the winding center hole 2a to improve the problem of the collapse of the winding center hole 2a, which is beneficial to improving the quality and service life of the electrode assembly 2, and thus beneficial to improving the quality and service life of the battery cell.

[0061] Moreover, by setting it in this way, the support needle body 10 can be pre-set in the winding center hole 2a of the electrode assembly 2, which is convenient to operate, conducive to realizing automated design, and will not damage the separator film 210 or the electrode tab 220, which is conducive to ensuring the flatness of the separator film 210 or the electrode tab 220, and thus conducive to ensuring the forming quality of the electrode assembly 2.

[0062] As Figure 3 shown, in some embodiments, the orthographic projection of the support needle body 10 on the axial direction X may be an annular structure. In this structure, the orthographic projection of the winding needle body 20 on the axial direction X may include but is not limited to one of a circular structure and a semi-circular structure, as long as it is ensured that the winding needle body 20 can be detachably connected to the support needle body 10.

[0063] Exemplarily, the orthographic projection of the support needle body 10 on the axial direction X is in an annular structure, and the orthographic projection of the winding needle body 20 on the axial direction X is in a circular structure, which is conducive to increasing the connection area between the support needle body 10 and the winding needle body 20, and thus conducive to ensuring that the two can rotate synchronously.

[0064] As Figure 6 shown, in some embodiments, the orthographic projection of the support needle body 10 on the axial direction X may be a semi-annular structure, and the number of the support needle bodies 10 may be set to two, and the two support needle bodies 10 are connected to each other. In this structure, the orthographic projection of the winding needle body 20 on the axial direction X may be in a semi-circular structure.

[0065] Optionally, the number of the winding needle bodies 20 may be set to one, and it is detachably connected to 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.

[0066] Optionally, the number of the winding needle bodies 20 may be set to two, and the winding needle bodies 20 and the support needle bodies 10 are arranged in a one-to-one manner.

[0067] In some embodiments, the support needle body 10 may be an integrally formed structure; in some embodiments, the support needle body 10 may further include two semi-annular structures and be formed by splicing the two semi-annular structures. In some embodiments, the support needle body 10 may further include two or more fan-shaped structures and be formed by splicing two or more fan-shaped structures.

[0068] 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 direction X may be an annular shape, an elliptical annular shape, a triangular annular shape, etc.

[0069] Among them, the winding needle body 20 can be made of stainless steel material to endow it with certain rigidity, which is beneficial to ensuring the rotation effect and preventing failure during rotation.

[0070] The support needle body 10 can be made of a material resistant to electrolyte corrosion. In the embodiment of the present application, the material of the support needle body 10 is adapted to the material of the separator 210, and both are PP composite materials. Optionally, 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 support effect and are also beneficial to reducing the influence on the weight of the electrode assembly 2.

[0071] In some embodiments, the winding needle body 20 can be set as a solid structure, which is beneficial to improving its own strength and ensuring the reliability and stability during rotation.

[0072] Optionally, the winding needle body 20 can be detachably connected to the inner ring surface 111 of the support needle body 10, or the winding needle body 20 can also be detachably connected to the end of the support needle body 10 on either side along the axial direction X.

[0073] As an example, a first connection portion can be provided at one end of the support needle body 10 along the axial direction X, and a second connection portion can be provided at one end of the winding needle body 20 along the axial direction X. The first connection portion and the second connection portion are detachably arranged. That is to say, the support needle body 10 and the winding needle body 20 can be detachably connected at their ends along the axial direction X, which is convenient for assembly and disassembly. For example, the first connection portion and the second connection portion can be connected by means of snap connection or by using fasteners such as bolts.

[0074] In some embodiments, a first mating portion is provided on the inner ring surface 111 of the support needle body 10, and a second mating portion is provided on the outer peripheral surface of the winding needle body 20. The first mating portion and the second mating portion are in contact and detachably connected.

[0075] By processing a first mating portion on the inner ring surface 111 of the support needle body 10 and processing a second mating portion on the outer ring surface 112 of the winding needle body 20, the two are detachably connected through the contact of the first mating portion and the second mating portion. By setting in this way, the connection area between the support needle body 10 and the winding needle body 20 can be increased, which is beneficial to improving the connection strength between the two, thus beneficial to ensuring the rotation effect of their synchronous rotation, and further beneficial to improving the reliability of the winding needle structure 100.

[0076] Optionally, a second mating portion may be provided on the portion of the winding needle body 20 inserted into the cavity 10a, and the support needle body 10 is provided with a first mating portion having the same area as the second mating portion. Of course, the entire portion of the winding needle body 20 inserted into the cavity 10a may be provided with the second mating portion.

[0077] Optionally, one of the first mating portion and the second mating portion may be provided as a recess 1111, and the other may be provided as a protrusion 21. The first mating portion and the second mating portion are detachably connected by a snap-fit method; alternatively, the first mating portion and the second mating portion may be provided as a threaded structure capable of being screwed together, and the first mating portion and the second mating portion are detachably connected by a threaded connection method; or at least one of the first mating portion and the second mating portion may be provided as a magnetically adsorbing material body, and the first mating portion and the second mating portion are detachably connected by a magnetic adsorption method.

[0078] Please refer to Figure 3 , in some embodiments, one of the first mating portion and the second mating portion 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 are snap-fitted.

[0079] The number of the protrusions 21 and the recesses is set to be the same, and the number of the protrusions 21 and the recesses can be set to two, three, or even more.

[0080] Optionally, the first mating portion is a protrusion 21 provided on the inner ring surface 111 of the support needle body 10, and the second mating portion is a recess 1111 provided on the outer peripheral surface of the winding needle body 20; or the first mating portion is a recess 1111 provided on the inner ring surface 111 of the support needle body 10, and the second mating portion is a protrusion 21 provided on the outer peripheral surface of the winding needle body 20.

[0081] Wherein, the extending direction of the protrusion 21 is the same as the extending direction of the recess 1111, which is convenient for the protrusion 21 to extend into the recess 1111 so that the two are snap-fitted.

[0082] Exemplarily, the protrusion 21 may be a structure protruding from the inner ring surface 111 of the support needle body 10 away from the outer ring surface 112, and the recess 1111 may be a structure recessed from the outer peripheral surface of the winding needle body 20 into its interior; or the protrusion 21 may be a structure protruding from the outer peripheral surface of the winding needle body 20 away from its interior, and the recess 1111 may be a structure recessed from the inner ring surface 111 of the support needle body 10 toward the outer ring surface 112.

[0083] For the winding needle structure 100 provided in some embodiments of the present application, the support needle body 10 and the winding needle body 20 can be detachably connected by a snap-fit method, which is convenient for installation and disassembly and is beneficial to improving the operation efficiency.

[0084] In some embodiments, the recess 1111 includes a groove formed by recessing from the inner ring surface 111 to the outer ring surface 112 of the support needle body 10.

[0085] The groove refers to a structure that is recessed from the inner ring surface 111 to the outer ring surface 112 of the support needle body 10 but does not penetrate the wall portion 11 of the support needle body 10.

[0086] The first mating portion may be a groove provided on the inner ring surface 111 of the support needle body 10, and the second mating portion is a protrusion 21 provided on the outer peripheral surface of the winding needle body 20. By setting it in this way, it is convenient for processing and assembly, and is also beneficial to ensuring the structural strength of the winding needle body 20, and is beneficial to ensuring that it has sufficient rotation effect. Moreover, since the weight of the support needle body 10 is reduced, the weight of the electrode assembly 2 including this support needle body 10 is reduced.

[0087] In some embodiments, the recess 1111 includes a hole that penetrates the wall portion 11 of the support needle body 10.

[0088] The hole refers to a structure that is recessed from the inner ring surface 111 to the outer ring surface 112 of the support needle body 10 and penetrates the wall portion 11. By setting it in this way, after the winding needle body 20 is withdrawn, the support needle body 10 has a hole, and the hole can serve as a channel for the electrolyte and gas of the electrode assembly 2 to flow through, so that the electrolyte and gas can have more space for storage, which is beneficial to improving the electrical performance of the battery cell. In addition, it is also beneficial to reducing the weight of the support needle body 10.

[0089] For the winding needle structure 100 provided in some embodiments of the present application, the first mating portion provided on the inner ring surface 111 of the support needle body 10 may be a recess 1111, and the recess 1111 may be set as a groove or a hole, which is beneficial to improving the diversity of the winding needle structure 100.

[0090] Optionally, the protrusion 21 may be movably connected to the winding needle body 20, that is, the protrusion 21 can extend out of the winding needle body 20 along the radial direction Y or retract into the interior of the winding needle body 20 to meet its assembly and disassembly with the support needle body 10.

[0091] In some embodiments, the protrusion 21 includes an elastic member, and the elastic member can extend or contract along the radial direction Y of the annular structure.

[0092] The elastic member may represent a structure having a certain elasticity and capable of elastic deformation. For example, the elastic member may include silica gel, rubber, etc.

[0093] 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 squeezed by the inner ring surface 111 of the support needle body 10, that is, the elastic member can be shortened along the radial direction Y 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 returns to its 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 support needle body 10; after the electrode assembly 2 is prepared and formed, the winding needle body 20 can be withdrawn along the axial direction X. At this time, the elastic member is deformed and leaves the recess 1111.

[0094] Exemplarily, the positive projection of the inner ring surface 111 of the support needle body 10 on the axial direction X is in an annular structure, the positive projection of the winding needle body 20 on the axial direction X is in a circular structure and is coaxially arranged with the support needle body 10. One of the convex 21 or the recess 1111 is provided on the inner ring surface 111 of the support needle body 10, and the other of the convex 21 or the recess 1111 is provided on the outer peripheral surface of the winding needle body 20. The convex 21 includes an elastic member.

[0095] The winding needle structure 100 provided by some embodiments of the present application is arranged in the above manner. Only by providing an axial X force capable of deforming the elastic member can the clamping or separation of the elastic member from the recess 1111 be realized, so as to facilitate the assembly and disassembly of the winding needle body 20 and the support needle body 10. The operation is simple and is beneficial to improving the operation efficiency.

[0096] Please refer to Figure 4 and Figure 5 , in some embodiments, the first matching portion includes an internal thread 1112 provided on the inner ring surface 111, and the second matching portion includes an external thread 22 provided on the outer peripheral surface.

[0097] The internal thread 1112 refers to a structure with a spiral shape processed on the inner ring surface 111 of the support needle body 10, and the external thread 22 refers to a structure with a spiral shape processed on the outer peripheral surface of the winding needle body 20. Thread connection means that the support needle body and the winding needle body 20 are connected by screwing to make the internal thread 1112 and the external thread 22 cooperate with each other.

[0098] In some embodiments of the present application, for the winding needle structure 100 provided, the support needle body and the winding needle body 20 can be detachably connected by means of a threaded connection, which is convenient for assembly and disassembly, and is beneficial to improving the operation efficiency; moreover, it is also beneficial to ensure the sealing requirement after their connection, so as to ensure that during the synchronous rotation of the two, external dust, impurities and other particles will not enter the support needle body 10 to contaminate the pole piece 220 or the separator 210, thereby being beneficial to ensuring the quality of the electrode assembly 2 after preparation and molding. In addition, it can also make the connection between the support needle body 10 and the winding needle body 20 more firm, reduce the noise influence during synchronous rotation, and ensure the connection stability during their rotation.

[0099] Exemplarily, the positive projection of the inner ring surface 111 of the support needle body 10 on the axial direction X is in an annular structure, the positive projection of the winding needle body 20 on the axial direction X is in a circular structure and is coaxially arranged with the support needle body 10. The inner ring surface 111 of the support needle body 10 is provided with an internal thread 1112, and the outer peripheral surface of the winding needle body 20 is provided with an external thread 22. The internal thread 1112 and the external thread 22 cooperate with each other for screwing connection.

[0100] In an alternative embodiment, the support needle body 10 is an integrally formed structure, and the starting end of the separator 210 is attached to the outer ring surface 112 of the support needle body 10, thereby completely covering the support needle body 10, so that there is at least one layer of separator 210 between the support needle body 10 and the pole piece 220.

[0101] As Figure 2 、 Figure 8 and Figure 9 As shown, in some embodiments, the support needle body 10 includes two or more sub-support bodies 101 distributed along its circumferential direction. The two or more sub-support bodies 101 enclose a cavity 10a, and at least one sub-support body 101 is detachably connected to the winding needle body 20.

[0102] The number of the sub-support bodies 101 can be set to two, three, or more. By setting in the above manner, the starting end of the separator 210 or the pole piece 220 can be preset and clamped between adjacent two sub-support bodies 101 and then wound around its outer circumference, which is convenient for installation and positioning, and is also beneficial to improving the connection strength between the separator 210 or the pole piece 220 and the support needle body 10, so that the support body can better drive the separator 210 or the pole piece 220 to rotate.

[0103] In some embodiments, each sub-support body 101 is detachably connected to the winding needle body 20.

[0104] As Figure 8As shown, the number of sub - support bodies 101 is set to two. Each sub - support body 101 is detachably connected to the winding needle body 20. There are two docking parts formed between the two sub - support bodies 101. The starting end of the separator film 210 can be preset to be clamped in one of the docking parts, and is attached to the outer periphery of the winding needle body 20, and then extends out from the other docking part, so that the two sub - support bodies 101 can clamp the separator film 210, facilitating driving the separator film 210 to rotate. After the separator film 210 is wound a preset number of turns, the electrode tab 220 can be fed and wound together with the separator film 210 on the outer ring surface 112 of the support needle body 10.

[0105] In some embodiments, the winding needle body 20 is detachably connected to one of the sub - support bodies 101, and two or more sub - support bodies 101 are detachably connected to each other.

[0106] As Figure 9 As shown, the number of sub - support bodies 101 is set to two. The two sub - support bodies 101 enclose a cavity 10a. The winding needle body 20 is detachably connected to one of the sub - support bodies 101, and the two sub - support bodies 101 are detachably connected to each other, so that the rotation of the winding needle body 20 can drive all the sub - support bodies 101 to rotate synchronously.

[0107] Among them, two or more sub - support bodies 101 can be connected by means of clamping, bonding, etc.

[0108] It can be understood that since the separator film 210 or the electrode tab 220 is very thin, when assembling, the adjacent two sub - support bodies 101 can pass through the separator film 210 or the electrode tab 220 located between them to complete the assembly, and it will not affect the overall quality of the electrode assembly 2.

[0109] In some embodiments, the winding needle body 20 is coaxially arranged with the support needle body 10.

[0110] By coaxially arranging the winding needle body 20 and the support needle body 10, the support needle body 10 can rotate around the same axis as the winding needle body 20, which is beneficial to improving the stability of the support needle body 10 rotating with the winding needle body 20, and further improving the stability and uniformity of the separator film 210 wound on the support needle body 10, which is beneficial to improving the quality of the wound electrode assembly 2.

[0111] Exemplarily, the support needle body 10 includes two sub - support bodies 101 distributed along its circumferential direction. The shape of the winding needle body 20 is the same as the shape of the cavity 10a of the support needle body 10 and is coaxially arranged. The winding needle body 20 can be detachably connected to each sub - support body 101 by clamping.

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

[0113] The polygonal ring structure may include, but is not limited to, a triangular ring structure and a rectangular ring structure. Correspondingly, the polygonal structure may include, but is not limited to, a triangular structure and a rectangular structure.

[0114] In some embodiments, the positive projection of the inner ring surface 111 of the support needle body 10 on the axial direction X is an elliptical ring structure, the positive projection of the outer ring surface 112 of the support needle body 10 on the axial direction X is a circular ring structure, and the positive projection of the winding needle body 20 on the axial direction X is an elliptical structure and is coaxially arranged with the support needle body 10.

[0115] As Figure 9 shown, in some embodiments, the positive projection of the winding needle body 20 on the axial direction X is a fan-shaped structure. The winding needle body 20 has an arc surface 201 and a connecting surface 202 which are connected. The winding needle body 20 is connected to at least one sub-support body 101 through the arc surface 201.

[0116] When the positive projections of the inner ring surfaces 111 of the sub-support bodies 101 on the axial direction X are all arc-shaped structures, the winding needle body 20 can be set as a fan-shaped structure and is detachably connected to the inner ring surfaces 111 of the sub-support bodies 101 through the arc surface 201. Among them, there may be a gap between the connecting surface 202 of the winding needle body 20 and each sub-support body 101.

[0117] In some embodiments, the winding needle body 20 is connected to one of the sub-support bodies 101 through the arc surface 201, and 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.

[0118] In some embodiments, the winding needle body 20 is connected to each sub-support body 101, that is, the arc surface 201 of the winding needle body 20 can be located at the docking position of adjacent two sub-support bodies 101 so that the winding needle body 20 can drive each sub-support body 101 to rotate synchronously.

[0119] By setting in the above manner, it is beneficial to improve the diversity of the winding needle structure 100.

[0120] 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.

[0121] The diameter of the cavity 10a can be understood as the radial dimension of the inner ring surface 111.

[0122] As an example, the diameter of the cavity 10a can be, but is not limited to, 5mm, 7mm, 10mm, 13mm, 15mm, 17mm, 20mm, 22mm, 25mm, 27mm, 30mm, etc.

[0123] It can be understood that when the diameter of the cavity 10a is smaller, that is, greater than 5mm, it is not conducive to inserting the winding needle body 20 into the cavity 10a; while when the diameter of the cavity 10a is larger, that is, smaller than 30mm, the space occupied by the central hole will be relatively large, thereby reducing the energy density of the battery cell.

[0124] Therefore, by setting the diameter of the cavity 10a between 5mm and 30mm, including the two end values of 5mm and 30mm, the cavity 10a has sufficient space to be assembled with the winding needle body 20, which is convenient for processing the support needle body 10 to form a structural form that can be detachably connected to the winding needle body 20.

[0125] In some embodiments, the diameter of the cavity 10a is greater than or equal to 7mm and less than or equal to 15mm.

[0126] As an example, the diameter of the cavity 10a can be, but is not limited to, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.

[0127] By further setting the diameter of the cavity 10a between 7mm and 15mm, including the two end values of 7mm and 15mm, it can better meet the balance of facilitating the detachable connection between the support cavity 10a and the winding needle body 20 and reducing the impact on the energy density of the battery cell. That is to say, by setting in this way, while satisfying the insertion of the winding needle body 20, it is beneficial to improve the energy density of the battery cell.

[0128] In some embodiments, the diameter of the cavity 10a is greater than or equal to 7mm and less than or equal to 10mm.

[0129] In some embodiments, in the axial direction X, the ratio of the length dimension of the part of the winding needle body 20 inserted into the cavity 10a 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.

[0130] In some embodiments, the number of winding needle bodies 20 is set to one. 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 dimension of the first winding part 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.

[0131] By setting in the above manner, it is beneficial to ensure the effectiveness of the winding needle body 20 to drive the support needle body 10 to rotate synchronously.

[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 0.5 and less than or equal to 0.8.

[0133] 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.

[0134] 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.

[0135] In some embodiments, the number of winding needle bodies 20 can be set to one. Correspondingly, the driving mechanism 200 is also set to one. The support needle body 10 has at least one opening communicating with the cavity 10a along the axial direction X. The winding needle body 20 can be inserted into the cavity 10a along the opening to be detachably connected to the support needle body 10.

[0136] As Figure 4 shown, 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 communicating with the cavity 10a on both sides along the axial direction X. One of the paired winding needle bodies 20 is inserted into the cavity 10a through the first opening 10b, and the other is inserted into the cavity 10a through the second opening.

[0137] The number of winding needle bodies 20 can be set to two. Correspondingly, the driving mechanisms 200 are also set to two. The support needle body 10 is respectively provided with a first opening 10b and a second opening communicating with the cavity 10a at both ends along the axial direction X. One winding needle body 20 is inserted into the cavity 10a through the first opening 10b to be detachably connected to the support needle body 10, and the other winding needle body 20 is inserted into the cavity 10a through the second opening to be detachably connected to the support needle body 10. The two driving mechanisms 200 drive the two winding needle bodies 20 to rotate simultaneously so that the support needle body 10 rotates synchronously.

[0138] The winding needle structure 100 provided in some embodiments of the present application is arranged in the above manner, which is beneficial to improving the stability of the rotation of the support needle body 10 following the winding needle body 20.

[0139] 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 along the axial direction X. The first winding portion is 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.

[0140] Each winding needle body 20 has a first winding portion and a second winding portion connected along the axial direction X. The first winding portion is inserted into the cavity 10a. In the axial direction X, the ratio of the length dimension of each first winding portion to the length dimension of the support needle body 10 is greater than or equal to 0.1 and less than or equal to 0.5.

[0141] In some embodiments, the wall portion 11 of the support needle body 10 has a through-flow guiding hole, and the through-flow guiding hole communicates with the cavity 10a.

[0142] The through-flow guiding hole is used for allowing the electrolyte and gas to pass through. Optionally, the number of the through-flow guiding holes can be set to one, two, or multiple. The setting of the through-flow guiding holes can reduce the weight of the support needle body 10 and can also reduce the influence of the support needle body 10 on the electrode assembly 2 during charge and discharge, so that there is more accommodation space for electrode reaction substances inside the battery cell.

[0143] Optionally, at least part of the multiple through-flow guiding holes can be distributed at intervals along the axial direction X of the support needle body 10, and at least part of the multiple through-flow guiding holes can also be distributed at intervals along the circumferential direction of the support needle body 10 to ensure the uniform flow of the electrolyte.

[0144] The embodiment of the present application also provides a winding device, which includes the winding needle structure 100 provided in any of the above embodiments and a driving mechanism 200. The driving mechanism 200 is connected to one end of the winding needle body 20 along the axial direction X to drive the winding needle body 20 to rotate.

[0145] The winding device provided by the embodiment of the present application can automatically set the support needle body 10 with 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 thereof will not collapse, which is beneficial to improving the service life.

[0146] The winding device further includes 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 also be detachably connected to the mounting seat.

[0147] In some optional embodiments, the winding needle body 20 is detachably connected to the mounting seat, which is convenient for the maintenance or replacement of the winding needle body 20.

[0148] In some embodiments, the winding device further includes a drawing-out mechanism. The drawing-out mechanism drives the winding needle body 20 to move along the axial direction X to separate the winding needle body 20 from the support needle body 10.

[0149] Optionally, the drawing-out mechanism can be connected to the mounting seat to drive the winding needle body 20 to move along the axial direction X to draw out the winding needle body 20 from the cavity 10a of the support needle body 10.

[0150] Optionally, the extraction mechanism may include a cylinder assembly, which may include a cylinder and a connecting rod. The connecting rod is 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.

[0151] Please continue to refer to Figures 1 to 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 cell, including a housing, 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 disposed in the winding center hole 2a.

[0152] The housing is a component for forming the internal environment of the battery cell. The internal environment formed by it can be used to accommodate the electrode assembly 2, and can also be used to accommodate the electrolyte and other components. Optionally, the housing can be, but is not limited to, made of 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.

[0153] It can be understood that the winding needle structure 100 provided by the embodiments of the present application can be disposed in the winding center hole 2a of the electrode assembly 2, that is, after the electrode assembly 2 is manufactured using the winding needle structure 100, the winding needle body 20 does not need to be removed, which is beneficial to improving the manufacturing efficiency.

[0154] As Figure 7 shown, the number of the support needle bodies 10 can be set to two, and the positive projection of each support needle body 10 on the axial direction X is in a semi-circular ring structure. The positive projection of the winding needle body 20 on the axial direction X is in a fan-shaped structure, and the winding needle body 20 is disposed in the cavity 10a of one of the support needle bodies 10 and is detachably connected thereto. By setting in this way, after the electrode assembly 2 is prepared using the winding needle structure 100, the winding needle body 20 does not need to be removed, which is beneficial to further improving the support effect on the winding center hole 2a of the electrode assembly 2, and is also beneficial to improving the operation efficiency. Moreover, since the winding needle body 20 is only disposed in one of the support needle bodies 10, it is also beneficial to ensure the circulation of the electrolyte.

[0155] As Figure 9 shown, the winding needle body 20 includes two sub-support bodies 101. The positive projection of the winding needle body 20 on the axial direction X is in a fan-shaped structure, and the winding needle body 20 is disposed in one of the sub-support bodies 101 and is detachably connected to the sub-support body 101. By setting in this way, after the electrode assembly 2 is prepared using the winding needle structure 100, the winding needle body 20 does not need to be removed, which is beneficial to further improving the support effect on the winding center hole 2a of the electrode assembly 2, and is also beneficial to improving the operation efficiency. Moreover, since the winding needle body 20 is only disposed in one of the sub-support bodies 101, it is also beneficial to ensure the circulation of the electrolyte.

[0156] Of course, the support needle body 10 may further include three or even more sub-support bodies 101, and the number of winding needle bodies 20 may be set to two, three, or even more.

[0157] Of course, the support needle body 10 and the winding needle body 20 may also be configured in other structures other than the above embodiments, which will not be elaborated herein in this application.

[0158] The electrode assembly 2 includes a first pole piece 2201, a separator 210, and a second pole piece 2202 that are sequentially stacked along the winding direction.

[0159] Exemplarily, the separator 210 is disposed between the first pole piece 2201 and the second pole piece 2202, and the first pole piece 2201 is located inside the second pole piece 2202, and the second pole piece 2202 surrounds the first pole piece 2201. Therefore, the first pole piece 2201 is the positive pole piece, and the second pole piece 2202 is the negative pole piece, so as to avoid the phenomenon of metal precipitation during the charge and discharge process.

[0160] The winding needle structure 100 is disposed in the winding center hole 2a of the electrode assembly 2. Specifically, the separator 210 extends relative to the first pole piece 2201 in the winding direction and is stacked and wound with the support needle body 10.

[0161] Wherein, the separator 210 can be connected to the outer ring surface 112 of the support needle body 10 and adhered to the outer ring surface 112 of the support needle body 10, which is beneficial to ensuring the fixation of its relative position and also facilitating the support needle body 10 to drive the separator 210 to wind.

[0162] The winding needle structure 100 is located in the winding center hole 2a of the electrode assembly 2, and can provide a support stress from the inside of the battery cell to the outside for the electrode assembly 2, thereby preventing the first pole piece 2201 and the second pole piece 2202 from collapsing towards the center during the charge and discharge process.

[0163] In an alternative embodiment, in the axial direction X, the length dimensions of the separator 210, the first pole piece 2201, and the second pole piece 2202 are equal, and the length dimension of the winding needle structure 100 is smaller than the length dimensions of the separator 210, the first pole piece 2201, and the second pole piece 2202. That is to say, the winding needle structure 100 can be disposed in the winding center hole 2a of the electrode assembly 2, and its length dimension along the axial direction X is not greater than the dimension in the height direction of the battery cell, so as to be able to adapt to the outer shell of the battery cell.

[0164] In another alternative embodiment, in the axial direction X, the length dimensions of the separator 210, the first pole piece 2201, the second pole piece 2202, and the winding needle structure 100 are all set to be equal, so that the winding needle structure 100 can better provide a support effect.

[0165] For some embodiments of the present application, the battery cell is provided with a winding needle structure 100 in the winding center hole 2a of the electrode assembly 2 to support the winding center hole 2a, so as to improve the problem of collapse of the winding center hole 2a, which is beneficial to improving the quality and service life of the battery cell, and thus beneficial to improving the quality and service life of the battery.

[0166] Moreover, the winding needle body 20 in the winding needle structure 100 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 separator film 210 or the electrode plate 220 to rotate, so that the separator film 210 and the electrode plate 220 are wound around its outer ring surface 112 to form the electrode assembly 2. This manufacturing process will not damage the separator film 210 or the electrode plate 220, which is beneficial to ensuring the flatness of the separator film 210 or the electrode plate 220, and thus beneficial to ensuring the forming quality of the electrode assembly 2, and further beneficial to ensuring the forming quality of the battery cell.

[0167] In addition, it is also beneficial to realize automatic design and improve the manufacturing efficiency of the electrode assembly 2, thus beneficial to improving the manufacturing efficiency of the battery cell.

[0168] An embodiment of the present application provides a winding needle structure 100 for forming an electrode assembly 2. The winding needle structure 100 includes a support needle body 10 and a winding needle body 20.

[0169] The support needle body 10 has an annular structure and has a cavity 10a arranged along its own axial direction X. The inner ring surface 111 of the support needle body 10 is provided with a first matching portion and includes two sub-support bodies 101 distributed along its own circumferential direction. The two sub-support bodies 101 enclose to 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.

[0170] The winding needle body 20 is inserted into the cavity 10a. 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 detachably connected. 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 support needle body 10 to rotate synchronously. Among them, the first matching portion is set as a hole body penetrating through the wall portion 11 of the support needle body 10, and the second matching portion is set as a concave portion 1111. The hole body and the concave portion 1111 are matched in shape and are snap-fitted.

[0171] The positive projection of the winding needle body 20 in the axial direction X is in a fan-shaped structure and has an arc surface 201 and a connecting surface 202 connected. The winding needle body 20 is connected to one of the sub-support bodies 101 through the arc surface 201. The winding needle body 20 has a first winding portion and a second winding portion connected along the axial direction X. The first winding portion is inserted into the cavity 10a. In the axial direction X, 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 0.1 and less than or equal to 1.

[0172] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than 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; and 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 various embodiments of the present application, and they should all be covered by the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the various 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 that fall within the scope of the claims.

Claims

1. A coiling needle structure for forming an electrode assembly, characterized in that The coiling needle structure includes: A support needle body, which is in a ring structure and has a cavity arranged along its own axial direction; A coiling needle body, which is inserted into the cavity and is detachably connected to the support needle body. One end of the coiling needle body along the axial direction is configured to be connected to a driving mechanism to drive the support needle body to rotate synchronously.

2. The coiling needle structure according to claim 1, wherein A first fitting portion is arranged on the inner ring surface of the support needle body, and a second fitting portion is arranged on the outer peripheral surface of the coiling needle body. The first fitting portion and the second fitting portion are in contact fit and are detachably connected.

3. The coiling needle structure according to claim 2, wherein One of the first fitting portion and the second fitting portion is set as a concave portion, and the other is set as a convex portion. The convex portion and the concave portion are matched in shape and are in snap fit.

4. The coiling needle structure according to claim 3, characterized in that, The concave portion includes a groove body formed by being recessed from the inner ring surface to the outer ring surface of the support needle body, or the concave portion includes a hole body penetrating through the wall portion of the support needle body.

5. The coiling needle structure according to claim 3 or 4, characterized in that The convex portion includes an elastic member, and the elastic member can extend or contract along the radial direction of the ring structure.

6. The coiling needle structure according to claim 2, wherein The first fitting portion includes an internal thread arranged on the inner ring surface, and the second fitting portion includes an external thread arranged on the outer peripheral surface.

7. The coiling needle structure according to any one of claims 1 to 5, characterized in that, The support needle body includes two or more sub-support bodies distributed along its own circumferential direction. The two or more sub-support bodies enclose to form the cavity, and at least one of the sub-support bodies is detachably connected to the coiling needle body.

8. The winding needle structure according to claim 7, characterized in that The coiling needle body is coaxially arranged with the support needle body; or, the orthographic projection of the coiling needle body in the axial direction is in a fan-shaped structure. The coiling needle body has an arc surface and a connecting surface connected. The coiling needle body is connected to at least one of the sub-support bodies through the arc surface.

9. The coiling needle structure according to any one of claims 1 to 8, characterized in that, The diameter of the cavity is greater than or equal to 5 mm and less than or equal to 30 mm.

10. The coiling needle structure according to any one of claims 1 to 8, characterized in that, The diameter of the cavity is greater than or equal to 7 mm and less than or equal to 15 mm.

11. The coiling needle structure according to any one of claims 1 to 10, characterized in that, In the axial direction, the ratio of the length dimension of the part of the coiling needle body inserted into the cavity to the length dimension of the support needle body is greater than or equal to 0.1 and less than or equal to 1.

12. The winding needle structure according to any one of claims 1 to 11, characterized in that, The coiling needle bodies are arranged in pairs. The two sides of the support needle body along the axial direction have a first opening and a second opening communicating with the cavity. One of the coiling 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 coiling needle structure according to any one of claims 1 to 12, characterized in that, The wall portion of the support needle body has a through-flow guiding hole, and the through-flow guiding hole communicates with the cavity.

14. A winding device, characterized in that, It includes: The coiling needle structure according to any one of claims 1 to 13; A driving mechanism, which is connected to one end of the coiling needle body along the axial direction to drive the coiling needle body to rotate.

15. The winding device according to claim 14, characterized in that, The coiling device further includes a withdrawing mechanism, and the withdrawing mechanism drives the coiling needle body to move along the axial direction so that the coiling needle body is separated from the support needle body.

16. A battery cell, characterized in that, It includes: A housing; An electrode assembly, which is arranged in the housing, and the electrode assembly has a coiling central hole; The coiling needle structure according to any one of claims 1 to 13, and the coiling needle structure is arranged in the coiling central hole.

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