Winding device and winding method

Abstract

The present application relates to the technical field of batteries, and provides a winding device and a winding method. The winding device comprises a feeding mechanism and a winding needle. The feeding mechanism is used for conveying an electrode sheet and a separator, and the winding needle is used for winding the electrode sheet and the separator which are conveyed by the feeding mechanism to form an electrode assembly, wherein the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly formed by winding satisfies: (R / r)>10.

Description

Winding equipment and winding method

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 202410012761.2, filed on January 4, 2024, entitled “Winding Equipment and Winding Method”, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a winding device and a winding method. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] During the production of battery cells, the electrode sheets and separators are wound together to form the electrode assembly of the battery cell. Improving the reliability of battery cells is an important research direction in battery production.

[0006] Summary of the Invention

[0007] The present application aims to solve at least one of the technical problems in the background art. To this end, one object of the present application is to provide a winding device and a winding method to reduce the probability of collapse of the center hole of the electrode assembly and improve the reliability of the battery cell.

[0008] An embodiment of a first aspect of the present application provides a winding device, comprising a feeding mechanism and a winding needle, wherein the feeding mechanism is used to feed an electrode sheet and a separator; and the winding needle is used to wind the electrode sheet and separator fed by the feeding mechanism to form an electrode assembly, wherein the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding satisfies:

[0009] In the technical solution of the embodiment of the present application, the winding needle winds the electrode sheet and the diaphragm conveyed by the feeding mechanism to form an electrode assembly. The relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is satisfied: The diameter r of the winding needle is much smaller than the diameter R of the electrode assembly after winding, which can reduce the probability of the center hole of the electrode assembly collapsing after winding, thereby improving the reliability of the electrode assembly.

[0010] In some embodiments, the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is completed satisfies: The relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is completed satisfies: The probability of the central hole of the electrode assembly collapsing after winding can be further reduced, thereby further improving the reliability of the electrode assembly.

[0011] In some embodiments, the feeding mechanism includes an adjustment mechanism for clamping the electrode sheet and diaphragm and driving them to move to adjust the tension between the electrode sheet and the diaphragm. By clamping the electrode sheet and the diaphragm and driving them to move to adjust the tension between the electrode sheet and the diaphragm, the tension on the diaphragm and the electrode sheet applied to the winding needle during winding of the electrode assembly can be reduced, thereby reducing the probability of deformation of the winding needle and thereby increasing the service life of the winding needle.

[0012] In some embodiments, the adjustment mechanism may include a first roller and a second roller disposed opposite each other, with the electrode piece and the diaphragm passing between the first roller and the second roller. The first roller and the second roller are used to clamp the electrode piece and the diaphragm and drive them to move to adjust the tension of the electrode piece and the diaphragm. The first roller and the second roller disposed opposite each other in the adjustment mechanism can guide the conveyance of the electrode piece and the diaphragm, thereby improving the smoothness of the conveyance process.

[0013] In some embodiments, during the acceleration phase of winding the electrode sheet and diaphragm, an adjustment mechanism drives the electrode sheet and diaphragm to move so that their movement speed is greater than or equal to the winding speed of the winding needle, thereby adjusting the tension of the electrode sheet and diaphragm. By using the adjustment mechanism to drive the electrode sheet and diaphragm to move so that their movement speed is greater than or equal to the winding speed of the winding needle during the acceleration phase of winding the electrode sheet and diaphragm, the tension of the diaphragm and the electrode sheet exerted on the winding needle during winding of the electrode assembly can be reduced, thereby reducing the probability of deformation of the winding needle and thereby increasing the service life of the winding needle.

[0014] In some embodiments, the winding needle is an integrally formed structure. This integrally formed structure can reduce the diameter of the winding needle, further reducing the diameter of the central hole of the electrode assembly formed by winding, thereby further reducing the probability of the central hole of the electrode assembly collapsing after winding, thereby further improving the reliability of the electrode assembly.

[0015] In some embodiments, the winding apparatus further includes an auxiliary winding needle, which is disposed on one side of the winding needle and clamps the starting ends of the electrode sheet and the separator together with the auxiliary winding needle. The auxiliary winding needle is disposed on one side of the winding needle and clamps the starting ends of the electrode sheet and the separator together with the auxiliary winding needle, facilitating winding of the electrode sheet and the separator by the winding apparatus and improving the winding efficiency of the electrode assembly by the winding apparatus.

[0016] In some embodiments, the winding apparatus further includes an auxiliary mechanism positioned on one side of the winding needle. The auxiliary mechanism abuts the outer periphery of the electrode assembly and rotates in a direction opposite to the winding direction of the winding needle to adjust the tension of the electrode sheet and diaphragm. By abutting the outer periphery of the electrode assembly and rotating in a direction opposite to the winding direction of the winding needle, the effect of the tension of the electrode sheet and diaphragm on the electrode assembly and the winding needle can be adjusted, thereby improving the yield rate of the electrode assembly and extending the service life of the winding needle.

[0017] In some embodiments, the auxiliary mechanism is arranged at the position where the pole piece and the diaphragm are wound into the winding needle. Placing the auxiliary mechanism at the position where the pole piece and the diaphragm are wound into the winding needle can improve the efficiency and probability of adjusting the tension of the pole piece and the diaphragm.

[0018] In some embodiments, the winding apparatus further includes a cutter for severing the electrode sheets and separators. The cutter is positioned on the side of the feed mechanism away from the winding needle. Positioning the cutter on the side of the feed mechanism away from the winding needle improves the reliability of the winding apparatus and contributes to increasing the yield rate of the wound electrode assembly.

[0019] An embodiment of a second aspect of the present application provides a winding method, the winding method comprising: conveying an electrode sheet and a separator to a winding needle; and winding the electrode sheet and the separator along a preset direction to form an electrode assembly. The relationship between the diameter r of the winding needle for winding the electrode assembly and the diameter R of the electrode assembly after winding is completed satisfies:

[0020] In the technical solution of the embodiment of the present application, the winding needle winds the conveyed electrode sheet and diaphragm to form an electrode assembly. The relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is satisfied: The diameter r of the winding needle is much smaller than the diameter R of the electrode assembly after winding, which can reduce the probability of the center hole of the electrode assembly collapsing after winding, thereby improving the reliability of the electrode assembly.

[0021] In some embodiments, the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is completed satisfies: The relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is completed satisfies: The probability of the central hole of the electrode assembly collapsing after winding can be further reduced, thereby further improving the reliability of the electrode assembly.

[0022] In some embodiments, the winding method may further include: during the acceleration phase of winding the electrode sheet and separator, controlling the movement speed of the electrode sheet and separator to be greater than or equal to the winding speed of the winding needle around the electrode sheet and separator, thereby adjusting the tension of the electrode sheet and separator. By controlling the movement speed of the electrode sheet and separator during the acceleration phase of winding the electrode sheet and separator so that the movement speed of the electrode sheet and separator is greater than or equal to the winding speed of the winding needle around the electrode sheet and separator, the tension of the separator and the electrode sheet exerted on the winding needle during winding of the electrode assembly can be reduced, thereby reducing the probability of deformation of the winding needle and thereby increasing the service life of the winding needle.

[0023] In some embodiments, the winding method may further include controlling the auxiliary mechanism to rotate in a direction opposite to a preset direction to adjust the tension of the electrode sheet and diaphragm. By rotating the auxiliary mechanism in a direction opposite to the winding direction of the winding needle, the effect of the tension of the electrode sheet and diaphragm on the electrode assembly and the winding needle can be adjusted, thereby improving the yield rate of the electrode assembly and extending the service life of the winding needle.

[0024] An embodiment of a third aspect of the present application provides a battery cell, which includes an electrode assembly wound by the winding device in the above embodiment.

[0025] An embodiment of a fourth aspect of the present application provides a battery, which includes the battery cell in the above embodiment.

[0026] An embodiment of the fifth aspect of the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0027] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on the drawings without paying creative work.

[0029] FIG1 is a schematic structural diagram of a winding device according to some embodiments of the present application;

[0030] FIG2 is a first schematic diagram of the deformation of a winding needle in some embodiments of the present application;

[0031] FIG3 is a second schematic diagram of the deformation of the winding needle in some embodiments of the present application;

[0032] FIG4 is a third schematic diagram of the deformation of the winding needle in some embodiments of the present application;

[0033] FIG5 is a schematic diagram of the tension on the winding needle in some embodiments of the present application;

[0034] FIG6 is a schematic structural diagram of a winding needle in some embodiments of the present application;

[0035] FIG7 is a flow chart of a winding method according to some embodiments of the present application.

[0036] Explanation of the accompanying symbols: 100, winding equipment; 110, feeding mechanism; 120, winding needle; 130, pole piece; 140, diaphragm; 150, electrode assembly; 160, adjustment mechanism; 161, first roller; 162, second roller; 121, winding needle auxiliary needle; 170, auxiliary mechanism; 180, cutter. DETAILED DESCRIPTION

[0037] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0039] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0040] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0041] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0042] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0043] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the 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 on the embodiments of the present application.

[0044] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0045] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0046] As an energy storage system, cylindrical lithium-ion batteries boast mature technology, high production efficiency, and strong reliability. They hold broad application prospects in civil, aviation, aerospace, military communications, and combat applications. In recent years, the continuous advancement of military and civilian energy storage systems has placed higher demands on the cycle life of lithium-ion batteries.

[0047] For cylindrical lithium-ion batteries, winding is an essential and particularly important process in the production and manufacturing of electrode assemblies. The specific method is to fix the laser-cut electrode sheets and diaphragms on the winding needle, and as the winding needle rotates, the diaphragm, positive electrode sheet, diaphragm and negative electrode sheet are rolled into an electrode assembly; then the shelling, welding, formation and other processes are carried out to form a cylindrical lithium-ion battery.

[0048] During the charging process of cylindrical lithium-ion batteries, the expansion of the negative electrode material drives the expansion of the electrode assembly, which is restricted by the battery's steel casing. This outward expansion of the electrode assembly is hindered, causing it to expand toward the center hole. Continuous charging exacerbates this process, causing the electrode assembly to collapse toward the center hole. The collapsed electrode assembly, accompanied by expansion and contraction between charging and non-charging states, increases the risk of the positive electrode cut surface puncturing the diaphragm, leading to increased self-discharge and low voltage in the electrode assembly. In severe cases, this can cause the electrode assembly to short-circuit, ignite, or explode, seriously compromising the safety of cylindrical lithium-ion batteries.

[0049] Based on the above considerations, in order to solve the problem of easy collapse of the center of the electrode assembly, this application proposes a winding device, in which a winding needle winds the electrode sheet and diaphragm delivered by the feeding mechanism to form an electrode assembly, and the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is satisfied: The diameter r of the winding needle is much smaller than the diameter R of the electrode assembly after winding, which can reduce the probability of the center hole of the electrode assembly collapsing after winding, thereby improving the reliability of the electrode assembly.

[0050] The winding equipment disclosed in the embodiment of the present application can be used to wind to form an electrode assembly, and the formed electrode assembly can be used to manufacture a battery, which can be applicable to various electrical devices. The electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiment of the present application does not impose any special restrictions on the above-mentioned electrical devices.

[0051] According to some embodiments of the present application, a winding device 100 is provided. FIG1 is a schematic structural diagram of a winding device 100 provided in some embodiments of the present application. Referring to FIG1 , the winding device 100 includes a feeding mechanism 110 and a winding needle 120. The feeding mechanism 110 is used to convey an electrode sheet 130 and a separator 140. The winding needle 120 is used to wind the electrode sheet 130 and the separator 140 conveyed by the feeding mechanism 110 to form an electrode assembly 150. The relationship between the diameter r of the winding needle 120 and the diameter R of the electrode assembly 150 after winding satisfies the following:

[0052] In the embodiment of the present application, the electrode sheet 130 may include a positive electrode sheet and a negative electrode sheet, and the separator 140 may include a first separator and a second separator. The first separator is located between the positive electrode sheet and the negative electrode sheet to separate the positive electrode sheet and the negative electrode sheet. The first separator and the second separator are located on either side of the negative electrode sheet, respectively. During the process of winding the electrode sheet 130 and the separator 140 to form the electrode assembly 150 by the winding device 100, the second separator can separate the positive electrode sheet and the negative electrode sheet. The winding device 100 winds the positive electrode sheet, the negative electrode sheet, the first separator and the second separator to form the electrode assembly 150.

[0053] In an embodiment of the present application, the feeding mechanism 110 can be used to place the coils of the electrode 130 and the diaphragm 140, and to transport the electrode 130 and the diaphragm 140 as needed. The feeding mechanism 110 can maintain the position of the feeding mechanism 110 unchanged during the process of transporting the electrode 130 and the diaphragm 140, so that the feeding mechanism 110 guides the movement direction and movement path of the electrode 130 and the diaphragm 140. The feeding mechanism 110 can be an active roller. When the electrode 130 and the diaphragm 140 need to be released, the feeding mechanism 110 can actively rotate under the drive of the motor to transport the electrode 130 and the diaphragm 140; the feeding mechanism 110 can also be a passive roller. When the electrode 130 and the diaphragm 140 need to be released, the feeding mechanism 110 can rotate driven by the electrode 130.

[0054] In the embodiment of the present application, the winding device 100 may include four feeding mechanisms 110, wherein two feeding mechanisms 110 may be used to transport the positive electrode sheet and the negative electrode sheet respectively, and two feeding mechanisms 110 may be used to transport the first diaphragm and the second diaphragm respectively.

[0055] In an embodiment of the present application, the winding needle 120 can be composed of two semicircular winding needles with semicircular cross-sections. During the winding process of the electrode assembly 150, the two semicircular winding needles clamp the first and second diaphragms to form a cylindrical structure. The winding needle 120 then rotates, and the negative electrode sheet and the positive electrode sheet are sequentially inserted into the rotating diaphragm 140 for winding. After the diameter of the electrode assembly 150 reaches the required size, the winding needle 120 is withdrawn, completing the production of the electrode assembly 150. The winding needle 120 can also be an integrated structure. During the winding process of the electrode assembly 150, the winding needle 120 and the auxiliary winding needle 120 can clamp the first and second diaphragms to form a cylindrical structure. The winding needle 120 then rotates, and the negative electrode sheet and the positive electrode sheet are sequentially inserted into the rotating diaphragm 140 for winding. After the diameter of the electrode assembly 150 reaches the required size, the winding needle 120 is withdrawn, completing the production of the electrode assembly 150.

[0056] In one example, experiments were conducted on electrode assemblies 150 with central hole radii of 5.5 millimeters (mm), 5 mm, and 4 mm, respectively, to determine the expansion rate of the electrode piece 130 when the central hole of the electrode assembly 150 collapsed. The experimental results showed that when the expansion rate of the electrode piece 130 reached 9.8%, the central hole of the electrode assembly 150 with a central hole radius of 5.5 mm began to collapse; when the expansion rate of the electrode piece 130 reached 11%, the central hole of the electrode assembly 150 with a central hole radius of 5 mm began to collapse; and when the expansion rate of the electrode piece 130 reached 14.3%, the central hole of the electrode assembly 150 with a central hole radius of 4 mm began to collapse. The experimental results show that the smaller the radius of the central hole of the electrode assembly 150, the greater the expansion percentage of the electrode piece 130 that begins to collapse. In other words, the smaller the diameter of the winding needle 120, the better the internal support force of the central hole of the wound electrode assembly 150.

[0057] In the related art, the diameter R of the electrode assembly 150 after winding is less than or equal to 10 times the diameter r of the winding needle 120. In the embodiment of the present application, the relationship between the diameter r of the winding needle 120 and the diameter R of the electrode assembly 150 after winding satisfies: In other words, the diameter R of the wound electrode assembly 150 is at least 10 times the diameter r of the winding needle 120. The smaller the diameter of the winding needle 120, the smaller the radius of the center hole inside the wound electrode assembly 150. The smaller the radius of the center hole inside the electrode assembly 150, the greater the support strength of the center hole inside the electrode assembly 150. This reduces the probability of the center hole collapsing due to cyclic expansion during subsequent cyclic expansion of the electrode assembly 150.

[0058] In the embodiment of the present application, the winding needle 120 winds the electrode sheet 130 and the separator 140 delivered by the feeding mechanism 110 to form the electrode assembly 150. The relationship between the diameter r of the winding needle 120 and the diameter R of the electrode assembly 150 after winding satisfies: The diameter r of the winding needle 120 is much smaller than the diameter R of the electrode assembly 150 after winding, which can reduce the probability of the central hole of the electrode assembly 150 collapsing after winding, thereby improving the reliability of the electrode assembly 150.

[0059] According to some embodiments, the relationship between the diameter r of the winding needle 120 and the diameter R of the electrode assembly 150 after winding is completed satisfies:

[0060] In the embodiment of the present application, if the diameter r of the winding needle 120 is too small relative to the diameter R of the electrode assembly 150 after winding, the winding needle 120 will be more likely to deform during the winding process due to the small diameter r, which will reduce the service life of the winding needle 120. To reduce the probability of collapse of the center hole of the electrode assembly 150 and the probability of deformation of the winding needle 120, thereby increasing the service life of the winding needle 120, the diameter r of the winding needle 120 should not be too small relative to the diameter R of the electrode assembly 150 after winding. The diameter R of the electrode assembly 150 can be less than or equal to 15 times the diameter r of the winding needle 120.

[0061] In the embodiment of the present application, the relationship between the diameter r of the winding needle 120 and the diameter R of the electrode assembly 150 after winding is completed satisfies: The probability of the central hole of the electrode assembly 150 collapsing after winding can be further reduced, thereby further improving the reliability of the electrode assembly 150 .

[0062] According to some embodiments, the feeding mechanism 110 includes an adjusting mechanism 160 , which is used to clamp the pole piece 130 and the diaphragm 140 and drive the pole piece 130 and the diaphragm 140 to move, so as to adjust the tension of the pole piece 130 and the diaphragm 140 .

[0063] During the winding process of the electrode assembly 150, since the diaphragm 140 is mostly coated with ceramic, aramid and glue-coated diaphragm 140, this type of diaphragm 140 will be tightly adsorbed on the winding needle 120 due to static electricity during the winding process, which will cause misalignment due to spiral twisting during the winding process, resulting in the winding needle 120 being subjected to greater tension, and the winding needle 120 will produce deflection and deformation, which will affect the service life of the winding needle 120.

[0064] In one example, experiments were conducted on the deflection of the winding needle 120 when its diameter r was 5.5 mm and the tensions applied to it were 10 Newtons (N), 20 N, and 27 N. Figure 2 is a first schematic diagram of the deformation of the winding needle 120 according to some embodiments of the present application. Referring to Figure 2 , the maximum deformations of the winding needle 120 under tensions of 10 N, 20 N, and 27 N were 0.246 mm, 0.19 mm, and 0.112 mm, respectively. Reducing the tension from 27 N to 10 N reduced the maximum deflection by 54.47%.

[0065] In another example, experiments were conducted on the deflection of the winding needle 120 when its diameter r was 5.0 mm and the tensions applied to it were 10 N, 20 N, and 27 N. Figure 3 is a second schematic diagram of the deformation of the winding needle 120 according to some embodiments of the present application. Referring to Figure 3 , the maximum deformations of the winding needle 120 under tensions of 10 N, 20 N, and 27 N were 0.301 mm, 0.23 mm, and 0.129 mm, respectively. Reducing the tension from 27 N to 10 N reduced the maximum deflection by 57.14%.

[0066] In another example, the deflection of the winding needle 120 was tested when the diameter r of the winding needle 120 was 5.5 mm and 5 mm, respectively, and the winding needle 120 was subjected to a tension of 10 N. Figure 4 is a third schematic diagram of the deformation of the winding needle 120 in some embodiments of the present application. Referring to Figure 4 , under a tension of 10 N, the maximum deflection of the winding needle 120 with a diameter of 5.5 mm was 0.112 mm, and the maximum deflection of the winding needle 120 with a diameter of 5.0 mm was 0.129 mm.

[0067] It can be seen from the above description that the smaller the tension on the winding needle 120 is, the smaller the deflection deformation of the winding needle 120 is.

[0068] In some embodiments of the present application, FIG5 is a schematic diagram illustrating the tension applied to the winding needle 120. As shown in FIG5 , during the winding process of the electrode assembly 150, the tension applied to the winding needle 120 includes the tension of the electrode sheet 130 and the tension of the separator 140. Adjusting the tension applied to the winding needle 120 may include adjusting the tension of the electrode sheet 130 and the tension of the separator 140 simultaneously. The feeding mechanism 110 may include an adjusting mechanism 160, which can clamp the pole piece 130 and the diaphragm 140 and drive the pole piece 130 and the diaphragm 140 to move. The direction in which the adjusting mechanism 160 drives the pole piece 130 and the diaphragm 140 to move can be the same as the direction in which the winding needle 120 winds the pole piece 130 and the diaphragm 140. The speed at which the adjusting mechanism 160 drives the pole piece 130 and the diaphragm 140 to move can be greater than or equal to the speed at which the winding needle 120 winds the pole piece 130 and the diaphragm 140, thereby reducing the tension of the pole piece 130 and the tension of the diaphragm 140 on the winding needle 120.

[0069] In the embodiment of the present application, the electrode piece 130 and the diaphragm 140 are clamped by the adjustment mechanism 160 and the electrode piece 130 and the diaphragm 140 are driven to move to adjust the tension of the electrode piece 130 and the diaphragm 140. This can reduce the tension of the diaphragm 140 and the tension of the electrode piece 130 exerted on the winding needle 120 during the process of winding the electrode assembly 150, and can reduce the probability of deformation of the winding needle 120, thereby improving the service life of the winding needle 120.

[0070] According to some embodiments, as shown in FIG1 , the adjustment mechanism 160 may include a first roller 161 and a second roller 162 that are arranged opposite to each other, and the pole piece 130 and the diaphragm 140 pass between the first roller 161 and the second roller 162; the first roller 161 and the second roller 162 are used to clamp the pole piece 130 and the diaphragm 140 and drive the pole piece 130 and the diaphragm 140 to move so as to adjust the tension of the pole piece 130 and the diaphragm 140.

[0071] In some examples, the relative positions of first roller 161 and second roller 162 can be fixed. The pressure exerted by first roller 161 and second roller 162 on pole piece 130 and diaphragm 140 is small, and does not affect the normal movement of pole piece 130 and diaphragm 140. In other examples, the relative positions of first roller 161 and second roller 162 can be adjustable. For example, first roller 161 and second roller 162 can be moved away from or closer to each other to loosen or tighten pole piece 130 and diaphragm 140.

[0072] In some examples, the roller surfaces of the first roller 161 and the second roller 162 may be elastic, which can reduce the risk of the pole piece 130 and the diaphragm 140 being crushed.

[0073] Illustratively, the axial direction of the first roller 161 and the axial direction of the second roller 162 are parallel to the width direction of the pole piece 130 and the diaphragm 140 .

[0074] In the embodiment of the present application, when adjusting the tension of the electrode 130, the first roller 161 and the second roller 162 can clamp the electrode 130 and drive the electrode 130 to move. During the movement of the electrode 130, the first roller 161 and the second roller 162 press the electrode 130 from both sides. Under the action of pressure, the friction between the electrode 130 and the first roller 161 can reduce the relative slip between the electrode 130 and the first roller 161. The friction between the electrode 130 and the second roller 162 can also reduce the relative slip between the electrode 130 and the second roller 162, thereby driving the electrode 130 to move. The first roller 161 and the second roller 162 adjust the tension of the electrode 130 by adjusting the speed at which they drive the electrode 130 to move. Exemplarily, if the speed at which the first roller 161 and the second roller 162 drive the electrode 130 to move is greater than or equal to the speed at which the winding needle 120 winds the electrode 130, the tension of the electrode 130 can be reduced.

[0075] In the embodiment of the present application, the first roller 161 and the second roller 162 that are oppositely arranged and included in the adjustment mechanism 160 can guide the transmission of the electrode piece 130 and the diaphragm 140, thereby improving the stability of the electrode piece 130 and the diaphragm 140 during the transmission process.

[0076] According to some embodiments, during the winding acceleration stage of the pole piece 130 and the diaphragm 140, the adjustment mechanism 160 drives the pole piece 130 and the diaphragm 140 to move so that the moving speed of the pole piece 130 and the diaphragm 140 is greater than or equal to the winding speed of the winding needle 120 winding the pole piece 130 and the diaphragm 140, so as to adjust the tension of the pole piece 130 and the diaphragm 140.

[0077] In the process of the winding needle 120 winding the electrode sheet 130 and the diaphragm 140 to form the electrode assembly 150, it usually goes through a preparation stage (including preparatory work such as changing work stations and threading the needle), a pre-winding and feeding stage (winding begins, at this time the speed of the winding needle 120 is relatively slow), a winding acceleration stage (the speed of the winding needle 120 increases rapidly), a uniform speed winding stage (the speed of the winding needle 120 is relatively fast and remains unchanged), a deceleration winding stage (the speed of the winding needle 120 gradually decreases) and a finishing stage.

[0078] During the acceleration stage of winding the pole piece 130 and the diaphragm 140, the rotation speed of the winding needle 120 will increase rapidly, that is, the winding speed of the pole piece 130 and the diaphragm 140 by the winding needle 120 will also increase rapidly. At this time, if the moving speed of the pole piece 130 and the diaphragm 140 is less than the winding speed of the pole piece 130 and the diaphragm 140 by the winding needle 120, the tension of the pole piece 130 and the diaphragm 140 will increase, causing the winding needle 120 to bend and deform, thereby affecting the service life of the winding needle 120. In an embodiment of the present application, during the acceleration stage of winding the pole piece 130 and the diaphragm 140, the adjustment mechanism 160 drives the pole piece 130 and the diaphragm 140 to move so that the moving speed of the pole piece 130 and the diaphragm 140 is greater than or equal to the winding speed of the winding needle 120 winding the pole piece 130 and the diaphragm 140. The tension of the pole piece 130 and the diaphragm 140 can be adjusted to reduce the tension of the pole piece 130 and the diaphragm 140.

[0079] In an embodiment of the present application, during the acceleration stage of winding the electrode piece 130 and the diaphragm 140, the adjustment mechanism 160 drives the electrode piece 130 and the diaphragm 140 to move, so that the moving speed of the electrode piece 130 and the diaphragm 140 is greater than or equal to the winding speed of the winding needle 120 winding the electrode piece 130 and the diaphragm 140. This can reduce the tension of the diaphragm 140 and the tension of the electrode piece 130 on the winding needle 120 during the process of winding the electrode assembly 150, and can reduce the probability of deformation of the winding needle 120, thereby improving the service life of the winding needle 120.

[0080] According to some embodiments, the winding needle 120 is an integrally formed structure.

[0081] In related art, the winding needle 120 is primarily composed of two semicircular winding needles 120 with semicircular cross-sections. During the winding process of the electrode assembly 150, the two semicircular winding needles 120 clamp the separator 140 to form a cylindrical structure. The winding needle 120 then rotates, and the negative electrode and positive electrode sheets are sequentially inserted into the rotating separator 140 for winding. After the electrode assembly 150 reaches the required size, the winding needle 120 is withdrawn, completing the production of the electrode assembly 150. Due to the gap between the two semicircular winding needles 120, the diameter of the winding needle 120 composed of the two semicircular winding needles 120 is larger than that of a single-piece winding needle 120. Therefore, in order to reduce the diameter of the center hole of the electrode assembly 150, in the embodiment of the present application, the winding needle 120 is a single-piece structure.

[0082] In the embodiment of the present application, the cross-sectional shape of the winding needle 120 can be circular or elliptical, and the winding needle 120 can be a hollow structure or a solid structure.

[0083] For example, the cross-sectional shape of the winding needle 120 can be any shape such as circular or elliptical.

[0084] In an embodiment of the present application, the one-piece molded structure can reduce the diameter of the winding needle 120, further reduce the diameter of the center hole of the electrode assembly 150 formed by winding, thereby further reducing the probability of the center hole of the electrode assembly 150 collapsing after winding is completed, and further improving the reliability of the electrode assembly 150.

[0085] According to some embodiments, Figure 6 is a structural schematic diagram of the winding needle of some embodiments of the present application. As shown in Figure 5, the winding device 100 also includes a winding needle auxiliary needle 121. The winding needle auxiliary needle 121 is arranged on one side of the winding needle 120 and the starting end of the winding needle 120 clamping the pole piece 130 and the diaphragm 140.

[0086] In the embodiment of the present application, since the winding needle 120 is an integrally formed structure, it cannot clamp the electrode piece 130 and the separator 140 at the beginning of winding. The auxiliary winding needle 121 cooperates with the winding needle 120 to clamp the starting ends of the electrode piece 130 and the separator 140 to begin winding to form the electrode assembly 150.

[0087] In this embodiment of the present application, the cross-sectional shape of the winding needle auxiliary needle 121 corresponds to the shape of the winding needle 120. For example, if the winding needle 120 is circular, the winding needle auxiliary needle 121 is arc-shaped. The winding needle auxiliary needle 121 can conform to the outer surface of the winding needle 120 to facilitate clamping the starting ends of the electrode piece 130 and the diaphragm 140. After the winding device 100 has wound the electrode piece 130 and the diaphragm 140 to a predetermined thickness, the winding needle auxiliary needle 120 can be removed.

[0088] In an embodiment of the present application, a winding needle auxiliary needle 121 is provided on one side of the winding needle 120. The winding needle auxiliary needle 121 and the winding needle 120 clamp the starting ends of the pole piece 130 and the diaphragm 140, so as to facilitate the winding device 100 to wind the pole piece 130 and the diaphragm 140, thereby improving the winding efficiency of the winding device 100 for the electrode assembly 150.

[0089] According to some embodiments, the winding device 100 also includes an auxiliary mechanism 170, which is arranged on one side of the winding needle 120. The auxiliary mechanism 170 abuts against the outer periphery of the electrode assembly 150. The rotation direction of the auxiliary mechanism 170 is opposite to the winding direction of the winding needle 120 to adjust the tension of the electrode 130 and the diaphragm 140.

[0090] In the embodiment of the present application, the cross-section of the auxiliary mechanism 170 can be circular, and the axial length of the auxiliary mechanism 170 can be greater than or equal to the axial length of the winding needle 120. The axial length setting of the auxiliary mechanism 170 can achieve complete pressure on the electrode assembly 150, thereby improving the uniformity of tension relief on the electrode piece 130 and the diaphragm 140 at various positions of the electrode assembly 150. The outer diameter of the auxiliary mechanism 170 can be selected based on the diameter of the wound electrode assembly 150. For example, the outer diameter of the auxiliary mechanism 170 can be selected to be less than or equal to the diameter of the wound electrode assembly 150 to adjust the effect of the tension of the electrode piece 130 and the diaphragm 140 on the electrode assembly 150 and the winding needle 120, thereby improving the qualified rate of the electrode assembly 150 and extending the service life of the winding needle 120.

[0091] In the embodiment of the present application, the outer peripheral surface of the auxiliary mechanism 170 can be made of a flexible material, and the flexible material can be rubber or carbon fiber, etc., which has good wear resistance and surface smoothness, and can have a certain elasticity and flexibility. The auxiliary mechanism 170 made of a flexible material can reduce surface roughness and hardness, improve smoothness, avoid scratching or bumping the surface of the electrode assembly 150 or causing wrinkles on the pole piece 130 and the diaphragm 140, and improve the protection of the electrode assembly 150 to improve the pass rate of the electrode assembly 150. The outer peripheral surface of the auxiliary mechanism 170 can be an integrally formed structure with the internal structure of the auxiliary mechanism 170. For example, the auxiliary mechanism 170 is a rubber wheel, or a rubber layer is only wrapped around the outer peripheral side of the auxiliary mechanism 170, which is not limited here.

[0092] In an embodiment of the present application, the auxiliary mechanism 170 can abut against the outer periphery of the electrode assembly 150 and rotate relative to the electrode piece 130. By setting the rotation direction and abutment pressure of the auxiliary mechanism 170, it can rotate in the direction opposite to the winding direction in the early stage of winding, thereby isolating the tension between the electrode piece 130 and the diaphragm 140, reducing the pulling and pressure of the tension on the electrode piece 130 and the diaphragm 140, and thereby increasing the interlayer gap of the inner circle; in the later stage of winding, by applying pressure to the electrode assembly 150, the electrode piece 130 or the diaphragm 140 of the outer circle is pressed tightly, thereby reducing the winding gap of the outer circle, improving the difference in the interlayer gap between the inner circle and the outer circle, and then improving the center hole collapse problem and the lithium deposition problem of the outer circle of the electrode assembly 150, thereby improving the performance of the electrode assembly 150.

[0093] In the embodiment of the present application, the auxiliary mechanism 170 is in contact with the outer periphery of the electrode assembly 150, and the rotation direction of the auxiliary mechanism 170 is opposite to the winding direction of the winding needle 120. The influence of the tension of the electrode piece 130 and the diaphragm 140 on the electrode assembly 150 and the winding needle 120 can be adjusted, thereby improving the qualified rate of the electrode assembly 150 and extending the service life of the winding needle 120.

[0094] According to some embodiments, the auxiliary mechanism 170 is disposed corresponding to the position where the pole piece 130 and the diaphragm 140 are wound into the winding needle 120 .

[0095] In the embodiment of the present application, at the position where the pole piece 130 and the diaphragm 140 are about to be wound into the winding needle 120, the pole piece 130 and the diaphragm 140 at this position have a greater degree of freedom than the pole piece 130 and the diaphragm 140 at other positions of the electrode assembly 150. In order to improve the tension adjustment effect of the auxiliary mechanism 170, the auxiliary mechanism 170 is set at this position. Through the friction with the pole piece 130 and the diaphragm 140 at this position, the tension of the pole piece 130 and the diaphragm 140 at this position can be reduced, making the improvement effect more obvious.

[0096] In the embodiment of the present application, the auxiliary mechanism 170 is arranged at the position where the pole piece 130 and the diaphragm 140 are wound into the winding needle 120, which can improve the efficiency and probability of adjusting the tension of the pole piece 130 and the diaphragm 140.

[0097] According to some embodiments, the winding device 100 further includes a cutter 180 for cutting the pole piece 130 and the diaphragm 140 . The cutter 180 is disposed on a side of the feeding mechanism 110 away from the winding needle 120 .

[0098] In the embodiment of the present application, the cutter 180 is disposed on a side of the feeding mechanism 110 away from the winding needle 120. When the length of the electrode piece 130 or the diaphragm 140 reaches a predetermined length, the cutter 180 cuts the electrode piece 130 or the diaphragm 140. After the cutter 180 cuts the electrode piece 130 and the diaphragm 140, the feeding mechanism 110 can still feed the electrode piece 130 and the diaphragm 140 to the winding needle 120 for winding.

[0099] In the embodiment of the present application, the cutter 180 is arranged on the side of the feeding mechanism 110 away from the winding needle 120, which can improve the reliability of the winding device 100 and is conducive to improving the yield of the electrode assembly 150 formed by winding.

[0100] FIG7 is a flow chart of a winding method provided in some embodiments of the present application. As shown in FIG7 , the winding method includes:

[0101] Step S710: transporting the electrode and the diaphragm to the winding needle.

[0102] Step S720: The winding needle winds the electrode sheet 130 and the separator along a preset direction to form an electrode assembly, wherein the relationship between the diameter r of the winding needle for winding the electrode assembly and the diameter R of the electrode assembly after winding satisfies:

[0103] In the embodiment of the present application, the electrode sheet may include a positive electrode sheet and a negative electrode sheet, and the separator may include a first separator and a second separator. The first separator is located between the positive electrode sheet and the negative electrode sheet to separate the positive electrode sheet from the negative electrode sheet. The first separator and the second separator are respectively located on either side of the negative electrode sheet.

[0104] In the related art, the diameter R of the electrode assembly after winding is less than or equal to 10 times the diameter r of the winding needle. In the embodiment of the present application, the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding satisfies: In other words, the diameter R of the wound electrode assembly is at least 10 times the diameter r of the winding needle. Relatively speaking, in this application, a smaller winding needle diameter results in a smaller radius of the internal center hole of the wound electrode assembly. This smaller radius of the internal center hole of the electrode assembly provides greater support strength, reducing the probability of the internal center hole collapsing due to subsequent cyclic expansion of the electrode assembly.

[0105] In the embodiment of the present application, the winding needle winds the conveyed electrode sheet and the separator to form an electrode assembly. The relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is satisfied: The diameter r of the winding needle is much smaller than the diameter R of the electrode assembly after winding, which can reduce the probability of the center hole of the electrode assembly collapsing after winding, thereby improving the reliability of the electrode assembly.

[0106] According to some embodiments of the present application, the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is completed satisfies:

[0107] In the embodiments of the present application, if the winding needle diameter r is too small relative to the completed electrode assembly diameter R, the winding needle will be more likely to deform during the winding process due to the small diameter r, thereby reducing the service life of the winding needle. To reduce the probability of deformation of the winding needle while reducing the probability of collapse of the center hole of the electrode assembly and thereby increasing the service life of the winding needle, the winding needle diameter r should not be too small relative to the completed electrode assembly diameter R. The electrode assembly diameter R can be less than or equal to 15 times the winding needle diameter r.

[0108] In the embodiment of the present application, the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is completed satisfies: The probability of the central hole of the electrode assembly collapsing after winding can be further reduced, thereby further improving the reliability of the electrode assembly.

[0109] According to some embodiments of the present application, the winding method may further include: in the winding acceleration stage of winding the pole piece and the diaphragm, controlling the movement speed of the pole piece and the diaphragm to be greater than or equal to the winding speed of the winding needle winding the pole piece and the diaphragm to adjust the tension of the pole piece and the diaphragm.

[0110] In the process of winding the electrode sheets and diaphragms to form electrode assemblies, it usually goes through a preparation stage (including preparatory work such as changing work stations and threading the needle), a pre-winding and feeding stage (winding begins, at which time the needle speed is slow), an acceleration stage (the needle speed increases rapidly), a uniform winding stage (the needle speed is fast and remains unchanged), a deceleration winding stage (the needle speed gradually decreases), and a finishing stage.

[0111] During the acceleration phase of winding the electrode and diaphragm, the rotational speed of the winding needle increases rapidly. In other words, the winding speed of the electrode and diaphragm by the winding needle also increases rapidly. At this time, if the movement speed of the electrode and diaphragm is slower than the winding speed of the winding needle, the tension of the electrode and diaphragm will increase, causing the winding needle to bend and deform, thereby affecting the service life of the winding needle. In the embodiment of the present application, during the acceleration phase of winding the electrode and diaphragm, the movement speed of the electrode and diaphragm is controlled so that the movement speed of the electrode and diaphragm is greater than or equal to the winding speed of the winding needle. This can adjust the tension of the electrode and diaphragm and reduce the tension of the electrode and diaphragm.

[0112] In an embodiment of the present application, by controlling the moving speed of the electrode sheet and the diaphragm during the winding acceleration stage of the electrode sheet and the diaphragm, so that the moving speed of the electrode sheet and the diaphragm is greater than or equal to the winding speed of the electrode sheet and the diaphragm by the winding needle, the tension of the diaphragm and the electrode sheet on the winding needle during the process of winding the electrode assembly can be reduced, and the probability of deformation of the winding needle can be reduced, thereby improving the service life of the winding needle.

[0113] According to some embodiments of the present application, the winding method may further include: controlling the rotation direction of the auxiliary mechanism to be opposite to a preset direction to adjust the tension of the pole piece and the diaphragm.

[0114] In an embodiment of the present application, the auxiliary mechanism can abut against the outer periphery of the electrode assembly and rotate relative to the electrode piece. By setting the rotation direction and abutment pressure of the auxiliary mechanism, it can rotate in the direction opposite to the winding direction in the early stage of winding, thereby isolating the tension of the electrode piece and the diaphragm, reducing the pulling and pressure of the tension on the electrode piece and the diaphragm, and thus increasing the interlayer gap of the inner circle; in the later stage of winding, by applying pressure to the electrode assembly, the electrode piece or diaphragm of the outer circle is pressed tightly, thereby reducing the winding gap of the outer circle, improving the difference in the interlayer gap between the inner circle and the outer circle, and then improving the problem of central hole collapse of the electrode assembly and lithium deposition problem of the outer circle, thereby improving the performance of the electrode assembly.

[0115] In an embodiment of the present application, by making the rotation direction of the auxiliary mechanism opposite to the winding direction of the winding needle, the influence of the tension of the electrode sheet and the diaphragm on the electrode assembly and the winding needle can be adjusted, thereby improving the qualification rate of the electrode assembly and extending the service life of the winding needle.

[0116] An embodiment of the present application further provides a battery cell, which includes an electrode assembly wound by the winding device in the above embodiment.

[0117] The battery cells of the embodiments of the present application may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of the present disclosure are not limited to this. The battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of the present application are not limited to this. Battery cells are generally divided into cylindrical battery cells, prismatic battery cells, and soft-pack battery cells based on the packaging method, and the embodiments of the present application are not limited to this.

[0118] In the embodiment of the present application, the electrode assembly formed by winding with a winding device can reduce the probability of the central hole of the electrode assembly collapsing, thereby improving the reliability of the battery cell.

[0119] An embodiment of the present application further provides a battery, which includes a battery cell in any embodiment.

[0120] In the embodiments of the present application, the battery can be applied to, but not limited to, mobile phones, tablets, laptop computers, electric toys, electric tools, battery-powered vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0121] In the embodiment of the present application, the electrode assembly formed by winding with a winding device can reduce the probability of the central hole of the electrode assembly collapsing, improve the reliability of the battery cell, and thus improve the reliability of the battery.

[0122] An embodiment of the present application further provides an electrical device, which includes a battery in any embodiment, and the battery is used to provide electrical energy.

[0123] In the embodiments of the present application, the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0124] In the embodiment of the present application, by adopting the battery in the embodiment of the present application, the probability of the central hole of the electrode assembly collapsing can be reduced, thereby improving the reliability of the electrical device.

[0125] The technical solution of the present application is described below through a specific embodiment. As shown in Figures 1 to 6, the winding device 100 includes a feeding mechanism 110, a winding needle 120, an auxiliary mechanism 170 and a cutter 180. The winding needle 120 is an integrally formed structure, and the winding needle auxiliary needle 121 is provided on one side of the winding needle 120, and the winding needle 120 clamps the starting end of the electrode piece 130 and the diaphragm 140. The feeding mechanism 110 is used to convey the electrode piece 130 and the diaphragm 140; the winding needle 120 is used to wind the electrode piece 130 and the diaphragm 140 conveyed by the feeding mechanism 110 to form an electrode assembly 150, wherein the relationship between the diameter r of the winding needle 120 and the diameter R of the electrode assembly 150 after winding satisfies:

[0126] The feeding mechanism 110 includes an adjustment mechanism 160, which comprises a first roller 161 and a second roller 162 arranged opposite each other. The pole piece 130 and the diaphragm 140 pass between the first roller 161 and the second roller 162. The first roller 161 and the second roller 162 are used to clamp the pole piece 130 and the diaphragm 140 and drive the pole piece 130 and the diaphragm 140 to move, thereby adjusting the tension of the pole piece 130 and the diaphragm 140. During the winding acceleration phase of the pole piece 130 and the diaphragm 140, the adjustment mechanism 160 drives the pole piece 130 and the diaphragm 140 to move so that the movement speed of the pole piece 130 and the diaphragm 140 is greater than or equal to the winding speed of the winding needle 120 around the pole piece 130 and the diaphragm 140, thereby adjusting the tension of the pole piece 130 and the diaphragm 140.

[0127] The auxiliary mechanism 170 is set corresponding to the position where the electrode 130 and the diaphragm 140 are wound into the winding needle 120. The auxiliary mechanism 170 abuts against the outer periphery of the electrode assembly 150. The rotation direction of the auxiliary mechanism 170 is opposite to the winding direction of the winding needle 120 to adjust the tension of the electrode 130 and the diaphragm 140.

[0128] The cutter 180 is used to cut off the electrode piece 130 and the diaphragm 140 . The cutter 180 is disposed on a side of the feeding mechanism 110 away from the winding needle 120 .

[0129] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A winding device, comprising: A feeding mechanism for conveying the electrode sheet and the separator; The winding needle is used to wind the electrode sheet and the separator conveyed by the feeding mechanism to form an electrode assembly, wherein the relationship between the diameter r of the winding needle and the diameter R of the electrode assembly after winding is satisfied as follows:

2. The winding device according to claim 1, wherein The relationship between the diameter r of the coiling needle and the diameter R of the electrode assembly after coiling is satisfied as follows:

3. The winding device according to claim 1 or 2, wherein The feeding mechanism includes an adjusting mechanism for clamping the electrode sheet and the separator and driving the electrode sheet and the separator to move, so as to adjust the tension of the electrode sheet and the separator.

4. The winding device according to claim 3, wherein, The adjusting mechanism includes a first roller and a second roller arranged oppositely, and the electrode sheet and the separator pass between the first roller and the second roller; The first roller and the second roller are used for clamping the electrode sheet and the separator and driving the electrode sheet and the separator to move, so as to adjust the tension of the electrode sheet and the separator.

5. The winding device according to claim 3 or 4, wherein In the winding acceleration stage of winding the electrode sheet and the separator, the adjusting mechanism drives the electrode sheet and the separator to move, so that the moving speed of the electrode sheet and the separator is greater than or equal to the winding speed of the winding needle winding the electrode sheet and the separator, so as to adjust the tension of the electrode sheet and the separator.

6. The winding device according to any one of claims 1 to 5, wherein, The winding needle is of an integrally formed structure.

7. The winding device according to any one of claims 1 to 6, wherein, The winding device further includes a winding needle auxiliary needle, the winding needle auxiliary needle is arranged on one side of the winding needle, and the winding needle auxiliary needle and the winding needle clamp the starting ends of the electrode sheet and the separator.

8. The winding device according to any one of claims 1 to 7, wherein The winding device further includes an auxiliary mechanism, the auxiliary mechanism is arranged on one side of the winding needle, the auxiliary mechanism abuts against the outer periphery of the electrode assembly, and the rotation direction of the auxiliary mechanism is opposite to the winding direction of the winding needle, so as to adjust the tension of the electrode sheet and the separator.

9. The winding device according to claim 8, wherein, The auxiliary mechanism is arranged corresponding to the position where the electrode sheet and the separator are wound into the winding needle.

10. The winding device according to any one of claims 1 to 9, wherein, It further includes a cutter for cutting the electrode sheet and the separator, and the cutter is arranged on the side of the feeding mechanism away from the winding needle.

11. A winding method, the method comprising: Conveying the electrode sheet and the separator to the winding needle; The winding needle winds the electrode tab and the separator along a preset direction to form an electrode assembly, wherein the relationship between the diameter r of the winding needle for winding the electrode assembly and the diameter R of the electrode assembly after winding is satisfied 12. The method according to claim 11, wherein, The relationship between the diameter r of the coiling needle and the diameter R of the electrode assembly after coiling is satisfied as follows:

13. The method according to claim 11 or 12, wherein The method further includes: In the winding acceleration stage of winding the electrode sheet and the separator, controlling the moving speed of the electrode sheet and the separator to be greater than or equal to the winding speed of the winding needle winding the electrode sheet and the separator, so as to adjust the tension of the electrode sheet and the separator.

14. The method according to any one of claims 11 to 13, wherein, The method further includes: Controlling the rotation direction of the auxiliary mechanism to be opposite to the preset direction, so as to adjust the tension of the electrode sheet and the separator.

15. A battery cell, comprising an electrode assembly wound by the winding device according to any one of claims 1 to 10.

16. A battery, comprising the battery cell according to claim 15.

17. An electric device, the electric device includes the battery according to claim 16, and the battery is used to provide electric energy.

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