Battery cell winding device and method

Abstract

The invention discloses a battery cell winding device and method. The battery cell winding device is used for winding a first pole piece, a second pole piece, a first diaphragm and a second diaphragm into a battery cell, and comprises a winding needle assembly and a diaphragm folding piece, the winding needle assembly is arranged to rotate along a winding direction to wind a battery cell, the winding needle assembly comprises a first winding needle and a second winding needle which are arranged in parallel along a first direction, and a gap for the first diaphragm and the second diaphragm to pass through is formed between the first winding needle and the second winding needle. The diaphragm folding piece comprises an auxiliary needle arranged in the first direction and a driving piece for driving the auxiliary needle to rotate by a preset angle in the winding direction. According to the device and the method disclosed by the invention, the pole piece head coated with multiple layers of diaphragms can be formed in the battery cell, so that the safety of the battery cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing equipment, and in particular to a battery cell winding device and method for preparing wound-type battery cells. Background Art

[0002] The wound battery cell is a structure formed by winding the positive electrode sheet, negative electrode sheet and separator together with a winding needle, and a separator is arranged between the positive electrode sheet and the negative electrode sheet.

[0003] During the battery cell manufacturing process, the electrodes are pre-cut to a predetermined length before being wound. To prevent burrs from penetrating the separator and causing an internal short circuit, tape is typically applied to the cut locations to isolate the burrs.

[0004] However, cutting the electrode generates dust, which adheres to the electrode surface and affects the adhesive tape's adhesion, causing it to loosen or fall off. This can still negatively impact the safety of the battery cell. Furthermore, applying tape to the electrode inevitably reduces the cell's capacity to a certain extent, hindering the improvement of battery energy density. Summary of the Invention

[0005] In view of this, the present application provides a battery cell winding device and a winding method, which can improve the safety of the prepared battery cell.

[0006] The battery cell winding device provided in the embodiments of the present application is used to wind a first electrode sheet, a second electrode sheet, a first diaphragm, and a second diaphragm into a battery cell. The device comprises a winding needle assembly and a diaphragm folding member. The winding needle assembly is configured to rotate along a winding direction to wind a battery cell. The winding needle assembly comprises a first winding needle and a second winding needle arranged parallel to each other along a first direction, with a gap between the first and second winding needles for the first and second diaphragms to pass through. The diaphragm folding member comprises an auxiliary needle arranged along the first direction and a drive member that drives the auxiliary needle to rotate by a predetermined angle along the winding direction.

[0007] In some embodiments, the diaphragm folding member includes an elongated housing, a first end of the housing is connected to a driving device, and a second end of the housing is mounted with the auxiliary needle.

[0008] In this embodiment, the auxiliary needle has an air channel inside and a plurality of air holes on the auxiliary needle. The air channel and the air holes can generate adsorption force on the auxiliary needle for holding the first diaphragm and the second diaphragm.

[0009] In this embodiment, the auxiliary needle is connected to a vacuum source via a spiral air tube, and the spiral air tube is sleeved on the housing.

[0010] In some embodiments, the auxiliary needle includes a clamping rod that is driven to move closer and further apart, and the clamping rod is used to clamp the first septum and the second septum from both sides.

[0011] In some embodiments, a needle nozzle sleeve is provided inside the housing, the needle nozzle sleeve extends from the second end of the housing, and a needle insertion hole for accommodating the free end of the needle winding assembly is opened at the front end of the needle nozzle sleeve.

[0012] In this embodiment, both ends of the needle nozzle sleeve are respectively sleeved in a first bearing and a second bearing, and the first bearing and the second bearing are arranged in the sleeve housing.

[0013] In this embodiment, a positioning ring is provided on the housing; a sensor is provided on one side of the positioning ring, and the sensor detects the angle of rotation of the positioning ring to determine the rotation angle of the auxiliary needle.

[0014] In another embodiment, a battery cell winding apparatus is used to wind a first electrode sheet, a second electrode sheet, a first diaphragm, and a second diaphragm into a battery cell, and includes a turret mechanism and a diaphragm folding mechanism. The turret mechanism includes a winding station, a finishing station, and a blanking station arranged along a circumferential direction, each station being provided with a winding needle assembly. The diaphragm folding mechanism includes a mounting base and three diaphragm folding components mounted on the mounting base. Each diaphragm folding assembly is positioned opposite a winding needle assembly, and the diaphragm folding component includes an auxiliary needle arranged parallel to the winding needle assembly and a drive member that drives the auxiliary needle in the direction of rotation of the winding needle assembly.

[0015] A battery cell winding method for winding a first pole piece, a second pole piece, a first diaphragm, and a second diaphragm into a battery cell, comprising: Step 1: clamping the first diaphragm and the second diaphragm with a winding needle assembly, and the heads of the first diaphragm and the second diaphragm pass through the winding needle assembly to form free ends of the diaphragms; Step 2: Using an auxiliary needle to hold the free end of the diaphragm, and driving the auxiliary needle to move a preset angle along the winding direction of the winding needle assembly, so that the free end of the diaphragm bypasses the winding needle assembly and moves closer to the first diaphragm and the second diaphragm; Step three: insert the first pole piece and the second pole piece into the first diaphragm and the second diaphragm respectively, and make the inner circle of the head of one of the first pole piece and the second pole piece have at least three layers of diaphragms.

[0016] In summary, the battery cell winding device and method of the present application folds the first diaphragm and the second diaphragm along the winding direction of the battery cell, thereby forming at least three layers of diaphragms on the inner circle of the head of a selected electrode, thereby effectively preventing the diaphragm from being punctured and enhancing the safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figures 1(A) to 1(D) are schematic diagrams of an embodiment of a battery cell winding method of the present invention;

[0019] Figure 2 This is a structural diagram of an embodiment of a battery cell winding device of the present invention;

[0020] Figure 3 yes Figure 2 Structural diagram of the folded diaphragm;

[0021] Figure 4 yes Figure 3 a cross-sectional view of the folded diaphragm;

[0022] Figure 5 is a schematic diagram of another embodiment of the battery cell winding method of the present invention;

[0023] Figure 6 is a structural diagram of another embodiment of the battery cell winding device of the present invention;

[0024] Figure 7 yes Figure 6 A structural diagram of the battery cell winding device from another angle; DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] As shown in Figures 1(A) through 1(C), the battery cell winding device and method of the present invention are used to wind a strip of material composed of a first separator S1, a first electrode P1, a second separator S2, and a second electrode P2 stacked sequentially into a battery cell. One embodiment of the battery cell winding device includes a winding needle assembly 100 and a separator folding member 200.

[0027] The winding needle assembly 100 includes a first winding needle 110 and a second winding needle 120 arranged in parallel. The first winding needle 110 and the second winding needle 120 extend from the center position of a base 130 and can be driven to rotate in the base 130 to wind the material strip into a battery cell. They are also configured to be able to retract from the base 130 to separate the wound battery cell from the winding needle assembly 100.

[0028] The diaphragm folding member 200 is positioned near the needle assembly 100 and is used to pull and fold the free ends S12 of the first and second diaphragms S1 and S2, formed by the portions of the diaphragms that pass through the needle assembly 100, along the rotational direction of the needle assembly 100. This results in a three-layer diaphragm structure inside the head of the first pole piece P1, while the head of the second pole piece P2 is also covered on both sides by multiple layers of diaphragms. The presence of multiple layers of diaphragms between the heads of the first and second pole pieces P1 and P2 reduces the risk of burrs on the pole piece heads penetrating the single-layer first or second diaphragms S1 and S2.

[0029] The following describes in detail the process of the method for winding a battery cell by the battery cell winding device of this embodiment with reference to FIG. 1 (A) to FIG. 1 (C).

[0030] As shown in Figure 1(A), during the preparation phase, the first and second diaphragms S1 and S2 are guided from the respective winding rollers or unwinding rollers to the top of the winding needle assembly 100, where they are stacked into a diaphragm strip and then passed downward through the gap between the first and second winding needles 110 and 120. The two stacked diaphragms S1 and S2, after passing through the first and second winding needles 110 and 120, form the aforementioned diaphragm free end S12. The head of the diaphragm free end S12 is secured by the diaphragm folding member 200.

[0031] Please refer to Figure 1 (B). The folding diaphragm member 200 is driven to move the free end S12 of the diaphragm along the winding direction of the winding needle assembly 100. Its movement trajectory is shown by the arrow, so that the free end S12 of the diaphragm is attached to the outer side of the second diaphragm S2. In this way, the side of the diaphragm free end S12 that contacts the winding needle assembly 100 is covered on the surface of the winding needle assembly 100.

[0032] Subsequently, the first and second pole pieces P1 and P2 are inserted, i.e., the head of the first pole piece P1 is inserted between the first and second diaphragms S1 and S2, and the head of the second pole piece P2 is inserted outside the free end S12 of the diaphragm. After the insertion operation is completed, three layers of diaphragms exist between the head of the first pole piece P1 and the head of the second pole piece P2: the second diaphragm S2 and the free end S12 of the diaphragm formed by stacking the first and second diaphragms S1 and S2, thereby preventing the diaphragm between the heads of the first and second pole pieces P1 and P2 from being punctured.

[0033] Please refer to Figure 1 (C). After the first electrode sheet P1 and the second electrode sheet P2 are inserted, the first winding needle 110 and the second winding needle 120 rotate, and the two electrode sheets are brought between the two diaphragms by means of the friction between the diaphragms and the electrode sheets, thereby completing the winding of the battery cell.

[0034] In other embodiments, the electrode insertion operation shown in Figure 1(B) can be modified to that shown in Figure 1(D), where the second electrode P2 is inserted between the second diaphragm S2 and the diaphragm's free end S12, while the insertion position of the first electrode P1 remains unchanged. This allows for three layers of diaphragm to be present around the inner edge of the head of the second electrode P2. These two different electrode insertion designs correspond to different burr generation scenarios at the electrode head, and can be selected based on specific needs. The following description still uses the electrode insertion operation shown in Figures 1(A) to 1(C) as an example.

[0035] Figure 2 、 3 The embodiment shown in 4 is a single-station winding mechanism for executing the battery cell winding method shown in Figures 1 (A) to 1 (C), wherein a winding needle assembly 100 consisting of a first winding needle 110 and a second winding needle 120 arranged side by side extends forward from the surface of a base 130 and is used to clamp two diaphragms S1, S2 and two pole pieces P1, P2 and rotate to produce a battery cell C.

[0036] The diaphragm folding member 200 is mounted on one side of the needle winding assembly 100 via a mounting plate 201 and includes a long cylindrical housing 210. Housing 210 defines a hollow mounting space, the first end of which is sleeved onto a drive shaft 221 of a drive motor 220. A first bolt 222 and a first gasket 223 secure the drive shaft 221 to a stepped surface on the inner wall of the mounting space of housing 210, allowing the drive motor 220 to rotate the housing 210.

[0037] A nozzle sleeve 230 is mounted at the second end of the mounting space. The nozzle sleeve 230 comprises a cylindrical main body and a nozzle. The main body of the nozzle sleeve 230 is positioned within the mounting space of the housing 210 and is mounted to the inner wall of the housing 210 via a first bearing 231 and a second bearing 232 located at either end of the main body, allowing the nozzle sleeve 230 to rotate freely within the housing 210. The nozzle of the nozzle sleeve 230 extends from the mounting space of the housing 210. A tapered insertion hole 233 is defined at the front end of the nozzle, into which the free ends of the first and second winding needles 110, 120 are inserted. This prevents deformation of the free ends of the winding needles during winding of the battery cell. In some embodiments, the nozzle can also serve as a force-applying element to adjust the winding diameter of the winding needle assembly 100, thereby aligning the tabs of the battery cell C and facilitating cell removal. This type of winding diameter adjustment design is commonly used in the battery cell manufacturing industry and will not be described in detail here.

[0038] To stably mount the nozzle sleeve 230 within the housing 210, a first bearing 231, sleeved on one end of the main body of the nozzle sleeve 230, abuts against a stepped surface on the inner wall of the housing 210 and is locked to the nozzle sleeve 230 via a second bolt 234 and a second washer 235. The other end of the nozzle sleeve 230 is secured by a plurality of nuts attached to locking bolts 236 to prevent it from slipping out of the housing 210. With this design, the nozzle sleeve 230 is assembled between the locking bolts 236 and the stepped surface within the housing 210 and can rotate freely within the housing 210.

[0039] like Figures 2 to 4 As shown, the second end of the housing 210 has an integrally formed disc portion 211, on which a hollow rod-shaped auxiliary needle 212 is mounted. The auxiliary needle 212 is roughly parallel to the axis of the aforementioned needle winding assembly 100 so as to fully contact the diaphragm passing through the needle winding assembly 100 in the width direction of the diaphragm. A plurality of air holes 213 are provided on the wall of the auxiliary needle 212, which are connected to the hollow internal airway space of the auxiliary needle 212. One end of the auxiliary needle 212 is connected to a spiral air tube 215 via a connector 214, and the other end of the spiral air tube 215 is connected to a vacuum source. To ensure that the structure of this embodiment is stable and occupies a small space, the spiral portion of the spiral air tube 215 is mounted on the outer periphery of the housing 210.

[0040] In summary, before the diaphragm folding device 200 of this embodiment operates, the free ends of the first and second winding needles 110, 120 are inserted into the pin insertion holes 233 of the needle nozzle sleeve 230. Simultaneously, the first and second diaphragms pass through the gap between the two winding needles and contact the auxiliary needle 212. At this point, under the action of an external vacuum source, the multiple air holes 213 of the auxiliary needle 212 attract and secure the diaphragms. Subsequently, the drive motor 220 is activated, driving the housing 210 to rotate, thereby causing the auxiliary needle 212 on the disc portion 211 to rotate a certain angle from its initial position of attracting the diaphragm to another diaphragm folding position. During this process, because the needle nozzle sleeve 230 is connected to the housing 210 via the first and second bearings 231, 232, it is unaffected by the rotation of the drive motor 220 and does not rub against the free ends of the winding needles. When the driving motor 220 stops rotating, the needle nozzle sleeve 230 can still rotate along with the first winding needle 110 and the second winding needle 120 without being affected by the stopping of the motor.

[0041] To facilitate controlling the rotation angle of the auxiliary needle 212, a positioning ring 216 is fixedly mounted on the housing 210. The positioning ring 216 has a positioning hole 217 formed therein. A photoelectric sensor 218 is mounted on one side of the positioning ring 216. The photoelectric sensor 218 detects the position of the positioning hole 217 and provides a position signal for starting / stopping the motor.

[0042] Combine Figures 2 to 4Referring to Figures 1(A) to 1(C), the working process of the battery cell winding device of this embodiment is as follows: In the initial stage of the winding process, the first winding needle 110 and the second winding needle 120 extend from the base 130 and clamp the first diaphragm S1 and the second diaphragm S2, and the free ends of the two winding needles are inserted into the pin insertion holes 233 of the diaphragm folding member 200. At this time, the free end S12 of the diaphragm formed by the stack of the first diaphragm S1 and the second diaphragm S2 extends from between the two winding needles; then, the external vacuum source is activated, so that the free end S12 of the diaphragm is fixed by the auxiliary needle 212 of the diaphragm folding member 200. Then, the drive motor 220 of the diaphragm folding member 200 is activated, and the free end S12 of the diaphragm is folded along the battery cell winding direction through the sensing of the positioning hole 217 on the positioning ring 216 by the photoelectric sensor 218. Next, the first pole piece P1 and the second pole piece P2 are driven to be inserted into the set position of the diaphragm. In this embodiment, the first pole piece P1 is inserted between the first diaphragm S1 and the second diaphragm S2, and the second pole piece P2 is inserted between the free end S12 of the diaphragm and the first diaphragm S1, so that there are three layers of diaphragms on the inner periphery of the head of the first pole piece P1.

[0043] In a preferred embodiment, the battery cell winding device is further provided with a diaphragm cutting device 300. The diaphragm cutting device 300 includes a cutting mechanism 310 driven to approach / move away from the free end S12 of the diaphragm and a pad 320 arranged opposite to the cutting mechanism 310. When the cutting function needs to be performed, the cutting mechanism 310 is driven close to the free end S12 of the diaphragm and pushed against the pad 320, and then continues to move forward to cut the free end S12 of the diaphragm. The cutting mechanism 310 preferably has a heating function, for example, it can be a metal cutter supplemented by a heating rod or directly use a thermal resistance wire as a cutting mechanism, so that the heads of the two diaphragms can be hot-melt-bonded together, so that when the folding diaphragm member 200 folds the two diaphragms, the free ends of the two diaphragms will not spread out.

[0044] In other embodiments, the auxiliary needle of the folding diaphragm member 200 may also be implemented in the form of a clamping claw, which uses two clamping rods driven by a cylinder to clamp from both sides of the diaphragm free end S12, thereby also preventing the free ends of the two diaphragms from spreading apart.

[0045] Figure 5The illustrated embodiment is a multi-station winding device for performing the winding method illustrated in Figure 1 . In this embodiment, three sets of winding needle assemblies 410 extend from a turret mechanism 430 , each comprising a first winding needle 411 and a second winding needle 412 . During the battery cell winding operation, the three sets of winding needle assemblies 410 rotate with the turret mechanism 430 and are positioned sequentially at the winding station 431 , the finishing station 432 , and the unloading station 433 , respectively, to perform the battery cell winding, finishing and gluing, and battery cell unloading processes. The winding mechanism also includes a separator cutting mechanism 440 , consisting of a cutting mechanism 441 and a backing plate 442 . This mechanism is used to cut the separator tape after the winding needles are relocated from the winding station 431 to the finishing station 432 , allowing the winding needle assembly 410 relocated to the winding station 431 to begin a new winding operation and the winding needle assembly 410 relocated to the finishing station 432 to perform the finishing and gluing operation on the wound battery cell C. This transposition winding method is a common solution in the industry and will not be described in detail here.

[0046] like Figure 5 As shown, the battery cell winding method of this embodiment includes the following steps: first, the first diaphragm S1 and the second diaphragm S2 pass through the winding needle assembly 410 of the winding station 431 and expose a section of the diaphragm free end S12; then, the diaphragm folding mechanism 450 pulls the diaphragm free end S12 along the winding direction of the winding needle, so that the diaphragm free end S12 is attached to the outside of the second diaphragm S2, so that the bent portion of the diaphragm free end S12 in contact with the winding needle assembly 410 is covered on the winding needle assembly 410; then, the first pole piece P1 and the second pole piece P2 are inserted between the two diaphragms S1 and S2. The specific insertion method can refer to the design method of the embodiment of Figure 1 (A) to Figure 1 (C), so that there are three layers of diaphragms between the heads of the first pole piece P1 and the second pole piece P2, and the inner circle of the pole piece head that is prone to burrs has three layers of diaphragms; then, the winding needle assembly 410 at the winding station 431 rotates along the winding direction to complete the battery cell winding operation. After the winding is completed, the turret mechanism 430 flips over and switches positions, so that each winding needle mechanism 410 flips over one station in sequence. The winding needle mechanism 410 at the winding station 431 switches to the gluing station 432 to perform the final gluing operation of the battery cell C. The winding needle mechanism 410 originally located at the gluing station 432 switches to the unloading station 433 to remove the battery cell C from the winding needle mechanism 410.

[0047] like Figure 6 、 Figure 7 As shown, the multi-station battery cell winding device includes a winding mechanism and a diaphragm folding mechanism 450. The winding mechanism includes a turret mechanism 430 and three sets of winding needle assemblies 410 mounted on the turret mechanism 430. The three sets of winding needle assemblies 410 are located at the winding station, the finishing station, and the unloading station, and cyclically switch between the three stations with the turret mechanism 430 to perform the corresponding winding, finishing, and unloading operations.

[0048] The diaphragm folding mechanism 450 includes a mounting base 451, on which three groups of Figure 3 Each set of diaphragm folding members 200 corresponds to a corresponding set of winding needle assemblies 410. Mounting base 451 is mounted on a shifting motor 452, enabling the positions of the three sets of diaphragm folding members 200 to shift as the winding needles of the winding mechanism shift. To ensure synchronous rotation of the winding mechanism and diaphragm folding mechanism 450, a support shaft 460 is connected between the turret mechanism 430 and the mounting base 451.

[0049] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance.

[0050] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-mentioned embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. However, these modifications, changes, 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. They should all be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A battery cell winding device for winding a first pole piece, a second pole piece, a first diaphragm, and a second diaphragm into a battery cell, comprising: A winding needle assembly is configured to rotate along a winding direction to prepare a battery cell, the winding needle assembly comprising a first winding needle and a second winding needle arranged side by side along a first direction, with a gap between the first winding needle and the second winding needle for the first and second diaphragms to pass through; The diaphragm folding member includes an auxiliary needle arranged along the first direction and a driving member for driving the auxiliary needle to rotate a preset angle along the winding direction.

2. The battery core winding device according to claim 1, characterized in that: The diaphragm folding member includes a housing, a first end of the housing is connected to an output end of a driving device, and a second end of the housing is provided with the auxiliary needle.

3. The battery core winding device according to claim 2, characterized in that: The auxiliary needle has an air channel inside and a plurality of air holes connected to the air channel. The air channel is connected to a vacuum source. The air holes are used to adsorb the first diaphragm and the second diaphragm under the action of the vacuum source.

4. The battery core winding device according to claim 3, characterized in that: The airway of the auxiliary needle is connected to the vacuum source through a spiral air tube, and the spiral air tube is sleeved on the housing.

5. The battery core winding device according to claim 2, characterized in that: The auxiliary needle includes a clamping rod that can be driven to move closer and further apart, and the clamping rod is used to clamp the first septum and the second septum from both sides.

6. The battery core winding device according to claim 2, characterized in that: A needle nozzle sleeve is arranged inside the shell, the needle nozzle sleeve extends from the second end of the shell, and a needle insertion hole for accommodating the free end of the needle winding assembly is formed at the front end of the needle nozzle sleeve.

7. The battery core winding device according to claim 6, characterized in that: Both ends of the needle nozzle sleeve are respectively sleeved in a first bearing and a second bearing, and the first bearing and the second bearing are arranged in the sleeve housing.

8. The battery core winding device according to claim 2, characterized in that: A positioning ring is provided on the housing; a sensor is provided on one side of the positioning ring, and the sensor determines the rotation angle of the auxiliary needle by detecting the angle rotated by the positioning ring.

9. A battery cell winding device for winding a first pole piece, a second pole piece, a first diaphragm, and a second diaphragm into a battery cell, comprising: The turret mechanism includes a winding station, a finishing station, and a blanking station arranged along the circumferential direction. Each station is provided with a winding needle assembly, and the winding needle assembly is used to clamp the first diaphragm and the second diaphragm and wind the first diaphragm, the second diaphragm, the first electrode piece, and the second electrode piece into a battery cell; The diaphragm folding mechanism includes a mounting seat and three groups of diaphragm folding parts arranged on the mounting seat. Each diaphragm folding component is arranged opposite to a winding needle component, and the diaphragm folding component includes an auxiliary needle arranged parallel to the winding needle component and a driving component that drives the auxiliary needle to move along the rotation direction of the winding needle component.

10. A battery cell winding method for winding a first pole piece, a second pole piece, a first separator, and a second separator into a battery cell, comprising: Step 1: clamping the first diaphragm and the second diaphragm with a winding needle assembly, and the heads of the first diaphragm and the second diaphragm pass through the winding needle assembly to form free ends of the diaphragms; Step 2: Using an auxiliary needle to hold the free end of the diaphragm, and driving the auxiliary needle to move a preset angle along the winding direction of the winding needle assembly, so that the free end of the diaphragm bypasses the winding needle assembly and moves closer to the first diaphragm and the second diaphragm; Step three: insert the first pole piece and the second pole piece between the first diaphragm and the second diaphragm respectively, and make the inner circle of the head of one of the first pole piece and the second pole piece have at least three layers of diaphragms.

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