Electrode assembly winding device and winding method

Abstract

The present application discloses a winding device and a winding method for an electrode assembly. The winding device of an embodiment of the present application includes: a first winding needle for winding a pole piece and a diaphragm to form an electrode assembly; and a second winding needle arranged downstream of the first winding needle, the second winding needle being configured to wind the diaphragm passing through the first winding needle before the first winding needle winds the pole piece and the diaphragm, and to release the diaphragm when the first winding needle winds the pole piece and the diaphragm, so that the diaphragm released by the second winding needle is wound on the inner side of the pole piece. The winding device of an embodiment of the present application can increase the number of layers of diaphragm at the winding center of the electrode assembly during the preparation process of the electrode assembly, thereby reducing the risk of short circuit and improving the safety of the electrode assembly.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a winding device and a winding method for an electrode assembly. Background Art

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells.

[0003] During the production of battery cells, winding equipment is required to wind the electrode sheets and separators to form the battery cell's electrode assembly. The electrode assembly is the core component that enables the battery cell's charge and discharge functions, and its safety is a critical issue. If the safety of the electrode assembly cannot be guaranteed, the battery cell will be unusable. Therefore, how to enhance the safety of the electrode assembly is a pressing technical issue in battery technology. Summary of the Invention

[0004] The present application provides a winding device and a winding method for an electrode assembly, which can improve the safety of the electrode assembly.

[0005] In a first aspect, an embodiment of the present application provides a winding device for an electrode assembly, comprising:

[0006] a first winding needle, for winding the electrode sheet and the separator to form an electrode assembly; and

[0007] The second winding needle is arranged downstream of the first winding needle. The second winding needle is configured to wind the diaphragm passing through the first winding needle before the first winding needle winds the pole piece and the diaphragm, and release the diaphragm when the first winding needle winds the pole piece and the diaphragm, so that the diaphragm released by the second winding needle is wound on the inner side of the pole piece.

[0008] In the above scheme, a second winding needle is arranged downstream of the first winding needle to pre-store a certain size of diaphragm before the first winding needle winds the diaphragm and the electrode sheet; when the first winding needle rotates, the diaphragm stored in the second winding needle can be wound on the inner side of the electrode sheet. In this way, after the electrode assembly is wound and formed, the number of layers of the diaphragm at the winding center of the electrode assembly increases, thereby reducing the risk of lithium dendrites piercing the diaphragm and improving the safety of the electrode assembly.

[0009] In some embodiments, the first winding needle includes two first half shafts, which are arranged opposite to each other and are used to wind the pole piece and the diaphragm. Before the first winding needle winds the pole piece and the diaphragm, a portion of the diaphragm passes between the two first half shafts and is wound on the second winding needle.

[0010] In the above scheme, after the electrode assembly is formed, the diaphragm between the two first semi-axes is located on the inner side of the pole piece, which can increase the number of diaphragm layers at the winding center of the electrode assembly, thereby reducing the risk of lithium dendrites piercing the diaphragm and improving the safety of the electrode assembly.

[0011] In some embodiments, the first winding needle further includes two clamping members, which are arranged opposite to each other and respectively mounted on the two first half shafts, and the two clamping members can move relative to each other to clamp the diaphragm.

[0012] In the above solution, when the first winding needle needs to rotate to wind the diaphragm and the electrode sheet, the two clamping parts can approach each other to clamp the diaphragm, preventing the diaphragm from loosening during the winding process, reducing the risk of diaphragm wrinkling, and improving the safety of the electrode assembly.

[0013] In some embodiments, the first semi-shaft has an inner surface, the inner surfaces of the two first semi-shafts face each other, and the first semi-shaft is provided with a first groove recessed relative to the inner surface, and at least a portion of the clamping member is accommodated in the first groove.

[0014] In the above solution, the first groove is provided on the first semi-axle to provide installation space for the clamping member, thereby reducing the influence of the clamping member on the distance between the two first semi-axles and improving the winding effect.

[0015] In some embodiments, the first semi-shaft has an outer surface, the outer surfaces of the two first semi-shafts are arranged opposite to each other, and the first semi-shaft is provided with a second groove recessed relative to the outer surface.

[0016] In the above solution, the second groove can provide a channel for other components to be inserted into the interior of the electrode assembly.

[0017] In some embodiments, the winding device also includes a blanking device, which includes an inner clamping needle and an outer clamping needle. The inner clamping needle is used to insert into the second groove, and the outer clamping needle is used to move to the outside of the electrode assembly. The inner clamping needle and the outer clamping needle can move relative to each other to clamp the electrode assembly.

[0018] In this solution, to remove the electrode assembly from the first winding needle, the inner clamping needle is inserted into the second groove, and the outer clamping needle is moved to the outside of the electrode assembly. The inner and outer clamping needles move closer together to clamp the electrode assembly from both the inside and outside. At this point, the inner and outer clamping needles can pull the electrode assembly to remove it from the first winding needle.

[0019] In some embodiments, the second winding needle includes two second half shafts, which are arranged opposite to each other and used to wind the diaphragm. The two second half shafts are configured to be able to move relative to each other to clamp the diaphragm.

[0020] In the above solution, when the second winding needle needs to rotate to wind the diaphragm, the two second half shafts clamp the diaphragm to prevent the diaphragm from loosening during the winding process.

[0021] In some embodiments, the second winding needle further comprises a cutter, which is located between the two second semi-axes and is used to cut the diaphragm. The cutter is installed and protrudes from one of the second semi-axes, and the other second semi-axle is provided with a third groove for avoiding the cutter.

[0022] In the above solution, by providing a cutter, the diaphragm can be cut at a set position to ensure the size of the diaphragm wound on the second winding needle and improve the accuracy.

[0023] In some embodiments, the winding device further includes: a diaphragm discharge device, disposed upstream of the first winding needle and used to provide the diaphragm; and a pole piece discharge device, disposed upstream of the first winding needle and used to provide the pole piece.

[0024] In some embodiments, the diameter of the second winding needle is smaller than the diameter of the first winding needle.

[0025] In the above solution, the second winding needle rotates to store the separator. The number of revolutions determines the number of separator layers at the center of the electrode assembly. This solution allows for a specific number of revolutions based on the electrode assembly design to meet process requirements. This solution utilizes a relatively small diameter for the second winding needle, allowing for more revolutions and improving separator storage accuracy.

[0026] In a second aspect, an embodiment of the present application provides a winding method for an electrode assembly, comprising:

[0027] Provide pole pieces and diaphragms;

[0028] Pull the diaphragm through the first winding needle and fix the diaphragm to the second winding needle;

[0029] rotating the second winding needle so that the diaphragm is wound around the second winding needle;

[0030] The first winding needle is rotated while the second winding needle releases the diaphragm, so that the first winding needle winds the diaphragm and the electrode sheet to form an electrode assembly, wherein the diaphragm released by the second winding needle is wound on the inner side of the electrode sheet.

[0031] In the winding equipment and winding method of the electrode assembly provided in the embodiments of the present application, a second winding needle is arranged downstream of the first winding needle to pre-store a certain size of diaphragm before the first winding needle winds the diaphragm and the electrode sheet; when the first winding needle rotates, the diaphragm stored in the second winding needle can be wound on the inner side of the electrode sheet. In this way, after the electrode assembly is wound and formed, the number of layers of the diaphragm at the winding center of the electrode assembly increases, thereby reducing the risk of lithium dendrites piercing the diaphragm and improving the safety of the electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0033] Figures 1 to 5 They are schematic diagrams of winding devices in different working states according to some embodiments of the present application;

[0034] Figure 6 This is a schematic diagram of a winding device according to some embodiments of the present application when a blanking device clamps an electrode assembly;

[0035] Figure 7 A schematic structural diagram of an electrode assembly prepared by a winding device in some embodiments of the present application;

[0036] Figure 8 for Figure 2 An enlarged schematic diagram of the winding device shown at box A;

[0037] Figure 9 A schematic flow chart of a winding method for an electrode assembly provided in some embodiments of the present application.

[0038] In the accompanying drawings, the drawings are not necessarily drawn to scale.

[0039] The reference numerals in the specific embodiment are as follows:

[0040] 1. Electrode assembly; 11. Pole piece; 12. Diaphragm

[0041] 2. First winding needle; 21. First semi-axis; 211. Inner surface; 212. First groove; 213. Outer surface; 214. Second groove; 22. Clamping member

[0042] 3. Second winding needle; 31. Second half shaft; 32. Cutting knife; 311. Third groove;

[0043] 4. Diaphragm discharge device;

[0044] 5. Pole piece unloading device;

[0045] 6. Roller passing;

[0046] 7. Blanking device; 71. Inner clamping needle; 72. Outer clamping needle. DETAILED DESCRIPTION

[0047] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application 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 drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0049] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the 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.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0051] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0052] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0053] The term "plurality" used in this application refers to two or more (including two).

[0054] Battery cells, such as lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, have advantages such as high energy density, high power density, high cycle life, and long storage life. They are widely used in electrical devices suitable for battery cells. For example, electrical devices can include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered vehicles, gas-powered vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0055] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer, with the positive active material layer coated on the surface of the positive current collector. The positive current collector includes a positive current collecting region and a positive electrode tab protruding from the positive current collecting region. The positive current collecting region is coated with the positive active material layer, while at least a portion of the positive electrode tab is not coated with the positive active material layer. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes a positive active material. The positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, among others. The negative electrode sheet includes a negative current collector and a negative active material layer, with the negative active material layer coated on the surface of the current collector. The negative current collector includes a negative current collecting region and a negative electrode tab protruding from the negative current collecting region. The negative current collecting region is coated with the negative active material layer, while at least a portion of the negative electrode tab is uncoated with the negative active material layer. The negative current collector can be made of copper, and the negative active material layer includes a negative active material, such as carbon or silicon. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene).

[0056] In the related art, winding equipment is required to wind the electrode sheets and separators to form an electrode assembly. However, the inventors have discovered that in the electrode assemblies wound by the winding equipment, the number of separator layers at the center of the winding is relatively small. Furthermore, the electrode sheets near the winding center of the electrode assembly are prone to lithium deposition, and the deposited lithium dendrites can easily pierce the separator, causing a short circuit risk.

[0057] In view of this, the inventors improved the structure of the winding equipment of the electrode assembly to increase the number of layers of the separator at the winding center of the electrode assembly, reduce the risk of short circuit, and improve the safety of the electrode assembly.

[0058] The winding device of the embodiment of the present application is further described below with reference to the accompanying drawings.

[0059] Figures 1 to 5 They are schematic diagrams of winding devices in different working states according to some embodiments of the present application; Figure 6 This is a schematic diagram of a winding device according to some embodiments of the present application when a blanking device clamps an electrode assembly; Figure 7 Schematic diagram of the structure of the electrode assembly prepared by the winding equipment of some embodiments of the present application.

[0060] like Figures 1 to 7 As shown, the winding equipment of the electrode assembly of the embodiment of the present application includes: a first winding needle 2, used to wind the electrode piece 11 and the diaphragm 12 to form the electrode assembly 1; and a second winding needle 3, arranged downstream of the first winding needle 2, the second winding needle 3 is configured to wind the diaphragm 12 passing through the first winding needle 2 before the first winding needle 2 winds the electrode piece 11 and the diaphragm 12, and release the diaphragm 12 when the first winding needle 2 winds the electrode piece 11 and the diaphragm 12, so that the diaphragm 12 released by the second winding needle 3 is wound on the inner side of the electrode piece 11.

[0061] The electrode assembly 1 can be formed by winding two electrode sheets 11 and two separators 12. The separator 12 is an insulator between the two electrode sheets 11. For example, one electrode sheet 11 is a positive electrode sheet, and the other electrode sheet 11 is a negative electrode sheet.

[0062] The first winding needle 2 is an axial structure capable of rotation about its own axis. As it rotates, it winds the separator 12 and electrode sheet 11 together, forming the wound electrode assembly 1. The cross-section of the first winding needle 2 can be roughly elliptical, circular, or diamond-shaped. Optionally, the first winding needle 2 can be made of aluminum alloy or alloy steel.

[0063] The second winding needle 3 is an axial structure capable of rotation about its own axis. As the second winding needle 3 rotates, a portion of the diaphragm 12 is wound around it. The cross-section of the second winding needle 3 can be roughly elliptical, circular, or diamond-shaped. Optionally, the second winding needle 3 can be made of aluminum alloy or alloy steel.

[0064] The second winding needle 3 is located downstream of the first winding needle 2. Downstream means that the processing step is later. The diaphragm 12 first passes through the first winding needle 2 and then is transported to the second winding needle 3.

[0065] When it is necessary to prepare the electrode assembly 1, first pull the diaphragm 12 through the first winding needle 2 and fix the diaphragm 12 on the second winding needle 3; then, rotate the second winding needle 3 so that a part of the diaphragm 12 close to the free end is wound on the second winding needle 3; finally, rotate the first winding needle 2 and at the same time release the diaphragm 12 from the second winding needle 3, so that the first winding needle 2 winds the diaphragm 12 and the electrode piece 11 to form the electrode assembly 1, wherein the diaphragm 12 released by the second winding needle 3 is wound on the inner side of the electrode piece 11.

[0066] The second winding needle 3 can store a portion of the diaphragm 12 so that this portion of the diaphragm 12 can be wound around the surface of the first winding needle 2 when the first winding needle 2 rotates.

[0067] In this embodiment, a second winding needle 3 is arranged downstream of the first winding needle 2 to pre-store a diaphragm 12 of a certain size before the first winding needle 2 winds the diaphragm 12 and the electrode piece 11; when the first winding needle 2 rotates, the diaphragm 12 stored in the second winding needle 3 can be wound on the inner side of the electrode piece 11. In this way, after the electrode assembly 1 is wound and formed, the number of layers of the diaphragm 12 at the winding center of the electrode assembly 1 increases, thereby reducing the risk of lithium dendrites piercing the diaphragm 12 and improving the safety of the electrode assembly 1.

[0068] In some embodiments, the winding device further includes: a diaphragm discharge device 4 , which is arranged upstream of the first winding needle 2 and is used to provide the diaphragm 12 ; and a pole piece discharge device 5 , which is arranged upstream of the first winding needle 2 and is used to provide the pole piece 11 .

[0069] The separator discharging device 4 can release the separator 12 during the winding process of the electrode assembly 1. Exemplarily, the separator discharging device 4 includes a separator unwinding roller.

[0070] There may be two diaphragm discharge devices 4 , and the two diaphragm discharge devices 4 provide two diaphragms 12 for the electrode assembly 1 .

[0071] The electrode sheet unwinding device 5 can release the electrode sheet 11 during the winding process of the electrode assembly 1. Exemplarily, the electrode sheet unwinding device 5 includes an electrode sheet unwinding roller.

[0072] There can be two electrode sheet discharging devices 5 , and the two electrode sheet discharging devices 5 provide two electrode sheets 11 for the electrode assembly 1 .

[0073] In some embodiments, the winding device further includes a plurality of rollers 6 , which are used to guide the pole piece 11 and the diaphragm 12 into the first winding needle 2 .

[0074] In some embodiments, the diameter of the second winding needle 3 is smaller than the diameter of the first winding needle 2 .

[0075] The second winding needle 3 stores the diaphragm 12 by rotating, and the number of revolutions determines the number of layers of diaphragm 12 at the winding center of the electrode assembly 1. This embodiment can rotate a certain number of revolutions according to the design requirements of the electrode assembly 1 to meet the process requirements.

[0076] In this embodiment, the second winding needle 3 has a relatively small diameter, which allows the second winding needle 3 to rotate more times, thereby improving the precision of the storage diaphragm 12 .

[0077] In some embodiments, the first winding needle 2 includes two first half-axes 21, which are arranged opposite each other and are used to wind the pole piece 11 and the diaphragm 12. Before the first winding needle 2 winds the pole piece 11 and the diaphragm 12, a portion of the diaphragm 12 passes between the two first half-axes 21 and is wound around the second winding needle 3.

[0078] The positions of the two first semi-axes 21 can be relatively fixed; of course, the two first semi-axes 21 can also be close to or far away from each other.

[0079] Exemplarily, the first semi-shaft 21 may be a semicircular shaft.

[0080] In this embodiment, after the electrode assembly 1 is formed, the diaphragm 12 between the two first semi-axes 21 is located on the inner side of the pole piece 11. This can increase the number of layers of the diaphragm 12 at the winding center of the electrode assembly 1, thereby reducing the risk of lithium dendrites piercing the diaphragm 12 and improving the safety of the electrode assembly 1.

[0081] In some embodiments, the first winding needle 2 further includes two clamping members 22 . The two clamping members 22 are arranged opposite to each other and are respectively installed on the two first semi-axles 21 . The two clamping members 22 can move relative to each other to clamp the diaphragm 12 .

[0082] The two clamping members 22 can move closer to or farther from each other. Optionally, one clamping member 22 is fixed to one first semi-shaft 21, and the other clamping member 22 is movably connected to the other first semi-shaft 21, so that the two clamping members 22 can move closer to or farther from each other. Of course, alternatively, both clamping members 22 can be movably connected to both first semi-shafts 21.

[0083] Before the first winding needle 2 winds the pole piece 11 and the diaphragm 12 , a portion of the diaphragm 12 passes between the two clamping members 22 and is wound around the second winding needle 3 .

[0084] In this embodiment, when the first winding needle 2 needs to rotate to wind the diaphragm 12 and the electrode 11, the two clamping members 22 can approach each other to clamp the diaphragm 12, preventing the diaphragm 12 from loosening during the winding process, reducing the risk of wrinkling the diaphragm 12, and improving the safety of the electrode assembly 1.

[0085] Compared with the solution of using two first semi-axes 21 to clamp the diaphragm 12 , this embodiment uses the clamping member 22 to clamp the diaphragm 12 , which can relatively fix the positions of the two first semi-axes 21 , thereby simplifying the structure of the first winding needle 2 .

[0086] In some embodiments, the first winding needle 2 further includes a driving mechanism (not shown), which is mounted on the first semi-shaft 21 and connected to the clamping member 22 to drive the clamping member 22 to move.

[0087] In some embodiments, the first half shaft 21 has an inner surface 211 , and the inner surfaces 211 of the two first half shafts 21 face each other. The first half shaft 21 has a first groove 212 recessed relative to the inner surface 211 , and at least a portion of the clamping member 22 is accommodated in the first groove 212 .

[0088] A portion of the diaphragm 12 passes between the inner surfaces 211 of the two first semi-shafts 21 and is wound around the second winding needle 3 .

[0089] Optionally, the inner surfaces 211 of the two first semi-shafts 21 are parallel to each other.

[0090] In this embodiment, a first groove 212 is provided on the first semi-shaft 21 to provide an installation space for the clamping member 22 , thereby reducing the influence of the clamping member 22 on the distance between the two first semi-shafts 21 and improving the winding effect.

[0091] In some embodiments, the first half shaft 21 has an outer surface 213 , and the outer surfaces 213 of the two first half shafts 21 are disposed opposite to each other. The first half shaft 21 is provided with a second groove 214 that is recessed relative to the outer surface 213 .

[0092] The outer surface 213 of the first semi-shaft 21 is connected to the inner surface 211 of the first semi-shaft 21. The outer surface 213 of the first semi-shaft 21 is used to define the winding shape of the pole piece 11 and the diaphragm 12. Exemplarily, the outer surface 213 is an arc surface.

[0093] In this embodiment, the second groove 214 can provide a passage for other components to be inserted into the interior of the electrode assembly 1 .

[0094] In some embodiments, the winding device also includes a blanking device 7, which includes an inner clamping needle 71 and an outer clamping needle 72. The inner clamping needle 71 is used to insert into the second groove 214, and the outer clamping needle 72 is used to move to the outside of the electrode assembly 1. The inner clamping needle 71 and the outer clamping needle 72 can move relative to each other to clamp the electrode assembly 1.

[0095] When the electrode assembly 1 needs to be removed from the first winding needle 2, the inner clamping needle 71 is inserted into the second groove 214, and the outer clamping needle 72 moves to the outside of the electrode assembly 1. The inner clamping needle 71 and the outer clamping needle 72 approach each other to clamp the electrode assembly 1 from both the inside and outside. At this time, the inner clamping needle 71 and the outer clamping needle 72 can pull the electrode assembly 1 to remove the electrode assembly 1 from the first winding needle 2.

[0096] In some embodiments, two blanking devices 7 are provided. The two blanking devices 7 can make the electrode assembly 1 evenly stressed and reduce the risk of deformation of the electrode assembly 1.

[0097] After the electrode assembly 1 is removed by the blanking device 7 , the two blanking devices 7 can move away from each other to stretch the electrode assembly 1 , thereby gradually flattening the electrode assembly 1 .

[0098] Figure 8 for Figure 2 An enlarged schematic diagram of the winding apparatus is shown at box A.

[0099] like Figure 8 As shown, the second winding needle 3 includes two second half shafts 31 , which are arranged opposite to each other and are used to wind the diaphragm 12 . The two second half shafts 31 are configured to be able to move relative to each other to clamp the diaphragm 12 .

[0100] The two second half-shafts 31 are configured to move closer to or farther from each other. When the diaphragm 12 needs to pass between the two second half-shafts 31, the two second half-shafts 31 can move away from each other to increase the gap between the two second half-shafts 31, facilitating the diaphragm 12 to extend between the two second half-shafts 31. When the diaphragm 12 needs to be secured, the two second half-shafts 31 move closer to clamp the diaphragm 12.

[0101] In this embodiment, when the second winding needle 3 needs to rotate to wind the diaphragm 12 , the two second half shafts 31 clamp the diaphragm 12 to prevent the diaphragm 12 from loosening during the winding process.

[0102] In some embodiments, the second winding needle 3 further includes a cutter 32, which is located between the two second semi-axes 31 and is used to cut the diaphragm 12. The cutter 32 is installed and protrudes from one second semi-axle 31, and the other second semi-axle 31 is provided with a third groove 311 for avoiding the cutter 32.

[0103] When the two second semi-axles 31 are approaching each other, the cutter 32 cuts the diaphragm 12 . The third groove 311 can avoid the cutter 32 to avoid interference between the cutter 32 and the other second semi-axle 31 .

[0104] In this embodiment, the cutter 32 is provided to cut the diaphragm 12 at a set position, thereby ensuring the size of the diaphragm 12 wound on the second winding needle 3 and improving the accuracy.

[0105] Recombined below Figures 1 to 7 , describes in detail the process of winding the pole piece 11 and the diaphragm 12 by the winding equipment of the specific embodiment of the present application.

[0106] Reference Figure 1 , the traction diaphragm 12 passes between the two first half-shafts 21 , and then the traction diaphragm 12 passes between the two second half-shafts 31 .

[0107] Reference Figure 2 , the two second semi-axes 31 approach each other to clamp the diaphragm 12. In the process that the two second semi-axes 31 approach each other, the cutter 32 cuts off the diaphragm 12, and the cut portion of the diaphragm 12 falls off.

[0108] Reference Figure 3 , the second winding needle 3 rotates a set number of turns to wind the diaphragm 12 onto the second winding needle 3. Exemplarily, the second winding needle 3 rotates clockwise.

[0109] Reference Figure 4 The two clamping members 22 clamp the diaphragm 12, while the two second half-shafts 31 release the diaphragm 12. Then, the first winding needle 2 begins to rotate, winding around the diaphragm 12 and the pole piece 11. As the first winding needle 2 rotates, it drives the second winding needle 3 to rotate through the diaphragm 12, releasing the second winding needle 3 and allowing the diaphragm 12 to be wound around the first winding needle 2. For example, the first winding needle 2 rotates clockwise, driving the second winding needle 3 to rotate counterclockwise.

[0110] Reference Figure 5 As the first winding needle 2 rotates, the diaphragm 12 stored in the second winding needle 3 is completely released and wound around the first winding needle 2 .

[0111] Reference Figure 6 and Figure 7 After the electrode sheet 11 and separator 12 are wound and formed, the inner clamping pin 71 is inserted into the second groove 214, and the outer clamping pin 72 moves to the outside of the electrode assembly 1. The inner and outer clamping pins 71, 72 approach each other to clamp the electrode assembly 1 from both the inside and outside. At this point, the inner and outer clamping pins 71, 72 can pull the electrode assembly 1 to remove it from the first winding pin 2. After removing the electrode assembly 1, the two blanking devices 7 can move away from each other to stretch the electrode assembly 1, thereby gradually flattening it.

[0112] Figure 9 A schematic flow chart of a winding method for an electrode assembly provided in some embodiments of the present application.

[0113] like Figure 9 As shown, the winding method of the electrode assembly of the embodiment of the present application includes:

[0114] S100, provide pole pieces and diaphragms;

[0115] S200, pulling the diaphragm through the first winding needle and fixing the diaphragm to the second winding needle;

[0116] S300, rotating the second winding needle to wind the diaphragm around the second winding needle;

[0117] S400 , rotating the first winding needle while the second winding needle releases the diaphragm, so that the first winding needle winds the diaphragm and the electrode sheet to form an electrode assembly, wherein the diaphragm released by the second winding needle is wound on the inner side of the electrode sheet.

[0118] It should be noted that the relevant structure of the electrode assembly manufactured by the above-mentioned electrode assembly winding method and the first winding needle and the second winding needle used can refer to the electrode assembly and winding equipment provided in the above-mentioned embodiments.

[0119] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0120] 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 of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A winding device for an electrode assembly, characterized in that: include: A first winding needle (2) is used to wind the electrode sheet (11) and the diaphragm (12) to form an electrode assembly (1); as well as A second winding needle (3) is arranged downstream of the first winding needle (2), the diameter of the second winding needle (3) is smaller than the diameter of the first winding needle (2), and the second winding needle (3) is configured to wind the diaphragm (12) passing through the first winding needle (2) before the first winding needle (2) winds the pole piece (11) and the diaphragm (12), and release the diaphragm (12) when the first winding needle (2) winds the pole piece (11) and the diaphragm (12), so that the diaphragm (12) released by the second winding needle (3) is wound on the inner side of the pole piece (11).

2. The winding device according to claim 1, characterized in that The first winding needle (2) comprises two first half shafts (21), the two first half shafts (21) being arranged opposite to each other and used for winding the pole piece (11) and the diaphragm (12); Before the first winding needle (2) winds the pole piece (11) and the diaphragm (12), a portion of the diaphragm (12) passes between the two first semi-axes (21) and is wound around the second winding needle (3).

3. The winding device according to claim 2, characterized in that The first winding needle (2) further comprises two clamping members (22), the two clamping members (22) being arranged opposite to each other and respectively mounted on the two first half-axes (21), and the two clamping members (22) being capable of relative movement to clamp the diaphragm (12).

4. The winding device according to claim 3, characterized in that The first half shaft (21) has an inner surface (211), and the inner surfaces (211) of the two first half shafts (21) face each other; The first semi-shaft (21) is provided with a first groove (212) recessed relative to the inner surface (211), and at least a portion of the clamping member (22) is accommodated in the first groove (212).

5. The winding device according to claim 2, characterized in that The first half shaft (21) has an outer surface (213), and the outer surfaces (213) of the two first half shafts (21) are arranged opposite to each other; The first semi-shaft (21) is provided with a second groove (214) recessed relative to the outer surface (213).

6. The winding device according to claim 5, characterized in that The present invention also includes a blanking device (7), wherein the blanking device (7) includes an inner clamping needle (71) and an outer clamping needle (72), wherein the inner clamping needle (71) is used to be inserted into the second groove (214), and the outer clamping needle (72) is used to be moved to the outside of the electrode assembly (1), and the inner clamping needle (71) and the outer clamping needle (72) are capable of relative movement to clamp the electrode assembly (1).

7. The winding device according to any one of claims 1 to 6, characterized in that: The second winding needle (3) comprises two second half shafts (31), the two second half shafts (31) being arranged opposite to each other and used for winding the diaphragm (12); The two second half shafts (31) are configured to be capable of relative movement to clamp the diaphragm (12).

8. The winding device according to claim 7, characterized in that The second winding needle (3) further comprises a cutter (32), wherein the cutter (32) is located between the two second half shafts (31) and is used to cut the diaphragm (12); The cutter (32) is mounted on and protrudes from one of the second semi-axles (31), and the other second semi-axle (31) is provided with a third groove (311) for avoiding the cutter (32).

9. The winding device according to claim 1, characterized in that Also includes: a diaphragm discharge device (4), arranged upstream of the first winding needle (2) and used to provide the diaphragm (12); as well as A pole piece unloading device (5) is arranged upstream of the first winding needle (2) and is used to provide the pole piece (11).

10. A winding method for an electrode assembly, characterized in that: include: Providing a pole piece (11) and a diaphragm (12); Pulling the diaphragm (12) through the first winding needle (2) and fixing the diaphragm (12) to the second winding needle (3); Rotating the second winding needle (3) so that the diaphragm (12) is wound on the second winding needle (3); The first winding needle (2) is rotated, and the second winding needle (3) releases the diaphragm (12) at the same time, so that the first winding needle (2) winds the diaphragm (12) and the pole piece (11) to form an electrode assembly (1), wherein the diaphragm (12) released by the second winding needle (3) is wound on the inner side of the pole piece (11).

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