Diaphragm compounding device

Abstract

The utility model discloses a diaphragm compounding device which comprises a first compounding assembly and a second compounding assembly, and the first compounding assembly is used for pressing a pole piece and a lower diaphragm; the second composite assembly is arranged on the downstream of the first composite assembly in the feeding direction of the lower diaphragm and used for pressing the upper diaphragm and the lower diaphragm. Therefore, the pole piece can be firstly compounded with the lower diaphragm, so that the pole piece can be fixed on the surface of the lower diaphragm, mutual displacement of the pole piece and the lower diaphragm is avoided, and then the upper diaphragm and the lower diaphragm are compounded; and at the moment, the lower diaphragm is moved or the upper diaphragm covers the surface of the pole piece, so that the pole piece cannot deviate. Therefore, according to the diaphragm compounding device provided by the invention, the lower diaphragm and the upper diaphragm can be respectively compounded, the deviation of the pole piece is avoided in the process, and the compounding precision is improved.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to a separator composite device. Background Technology

[0002] In the production of composite electrodes, a separator needs to be laminated onto both surfaces of the electrode to form a composite electrode. During the lamination process, heating and pressurization are used to bond the adhesive on the separator surface to the electrode surface, thereby achieving the lamination of the separator and the electrode.

[0003] In the process of diaphragm and electrode lamination, the upper and lower diaphragms are typically conveyed as continuous strips, while the electrodes are usually placed individually between them. Therefore, the upper and lower diaphragms can be positioned and kept flat using tension rollers, etc. However, the discontinuously arranged electrodes are prone to displacement within the diaphragms. In related technologies, the upper diaphragm, electrode, and lower diaphragm are usually joined together by a single pressing process. However, if the electrode shifts during pressing, it is difficult to detect and correct the shifted electrode due to the covering effect of the upper diaphragm. Utility Model Content

[0004] To solve at least one of the above-mentioned technical problems, this application provides a diaphragm composite device that can composite the electrode sheet with the lower diaphragm and the upper diaphragm respectively, thereby improving the accuracy of electrode sheet composite. The technical solution adopted is as follows.

[0005] The diaphragm lamination apparatus provided in this application includes a first lamination station and a second lamination station. The first lamination station is equipped with a first driving component and a first lamination component. The first driving component drives the first lamination component to press the electrode sheet and the lower diaphragm together. The second lamination station is located downstream of the first lamination station along the feeding direction of the lower diaphragm. The second lamination station is equipped with a second driving component and a second lamination component. The second driving component drives the second lamination component to press the upper diaphragm and the lower diaphragm together.

[0006] In some embodiments of this application, the composite pressure of the second composite component is greater than the composite pressure of the first composite component.

[0007] In some embodiments of this application, the first composite station is further provided with a first support roller. The first support roller is disposed at the inlet of the first composite component. The first composite component includes a first lower pressure plate. The support surface of the first support roller is higher than the pressing surface of the first lower pressure plate. When the lower diaphragm is wound around the first support roller, there is a gap between the lower diaphragm and the pressing surface of the first lower pressure plate.

[0008] In some embodiments of this application, the second composite station is further provided with a movable roller group, which includes two movable rollers that are movable in the vertical direction. The two movable rollers are respectively arranged at the inlet and outlet of the second composite component along the feeding direction of the lower diaphragm. The second composite component includes a second lower pressure plate. The movable roller group is used to move upward after the upper diaphragm and the lower diaphragm are pressed together, so as to drive the composite electrode sheet to detach from the second lower pressure plate.

[0009] In some embodiments of this application, the second composite station is further provided with a second support roller. The second support roller is disposed at the entrance of the second composite component. The second support roller is offset from the movable roller. The second composite component includes a second upper pressure plate. The supporting surface of the second support roller is lower than the pressing surface of the second upper pressure plate. When the upper diaphragm is wound around the second support roller, there is a gap between the upper diaphragm and the pressing surface of the second upper pressure plate.

[0010] In some embodiments of this application, the first composite component includes a first pressure plate, the pressing surface of which is provided with vacuum holes for adsorbing and fixing the lower diaphragm and the electrode.

[0011] In some embodiments of this application, the first composite component includes a first lower pressure plate, and the first drive component includes a cylinder and a cam. The cam is connected to the first lower pressure plate, and the cylinder is connected to the cam to drive the cam to rotate. The cam is used to drive the first lower pressure plate to rise or fall.

[0012] In some embodiments of this application, the first composite component includes a first upper pressure plate and a first lower pressure plate, the first lower pressure plate being detachably mounted on the first drive component, and the first composite station is further provided with a third drive component, the third drive component driving the first upper pressure plate, the first upper pressure plate being detachably mounted on the third drive component.

[0013] In some embodiments of this application, the first composite component includes a first upper pressure plate, and the pressing surface of the first upper pressure plate is provided with a flexible pad.

[0014] In some embodiments of this application, the diaphragm composite device further includes a first unwinding structure for providing a lower diaphragm and a second unwinding structure for providing an upper diaphragm. Both the first unwinding structure and the second unwinding structure are disposed at the first composite station. The first unwinding structure is disposed below the first composite assembly. The first unwinding structure is used to provide the lower diaphragm, and the second unwinding structure is disposed below the first composite assembly.

[0015] The embodiments of this application have at least the following beneficial effects: By setting a first composite station and a second composite station in the diaphragm composite device, and respectively setting a first composite component and a second composite component, with the two composite stations arranged sequentially along the feeding direction of the lower diaphragm, the diaphragm composite device can sequentially press the electrode sheet with the lower diaphragm and the upper diaphragm, that is, the electrode sheet is first composited with the lower diaphragm, so that the electrode sheet can be fixed on the surface of the lower diaphragm, avoiding mutual displacement between the electrode sheet and the lower diaphragm. Then, the upper diaphragm is composited with the lower diaphragm. Since the electrode sheet has been initially fixed on the lower diaphragm, moving the lower diaphragm or covering the electrode sheet surface at this time will not cause the electrode sheet to shift. After the upper and lower diaphragms are composited, the electrode sheet can be fixed between the upper and lower diaphragms in a preset position. In subsequent processes, the diaphragm is cut to a suitable shape to obtain the composite electrode sheet. It can be seen that the diaphragm composite device provided by this application can realize the separate composite of the lower and upper diaphragms, and avoid electrode sheet shifting in the process, thereby improving the composite accuracy. At the same time, the two composite stations can work simultaneously, that is, the lower diaphragm strip can be pressed with the electrode and the upper diaphragm at different parts at the same time, so that the electrode can be pressed with the lower diaphragm and the upper diaphragm separately and continuously, thus improving the composite efficiency. Attached Figure Description

[0016] The present application will be further illustrated below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments illustrated in the following drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application.

[0017] Figure 1 A schematic diagram of an example of a diaphragm composite device provided in an embodiment of this application;

[0018] Figure 2 A schematic diagram of the first composite station of the diaphragm composite device provided in the embodiments of this application;

[0019] Figure 3 A schematic diagram of the structure of the first composite component of the diaphragm composite device provided in the embodiments of this application;

[0020] Figure 4 A side view of the first composite component of the diaphragm composite device provided in an embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the second composite station of the diaphragm composite device provided in the embodiments of this application;

[0022] Figure 6 This is a schematic diagram of another example of the diaphragm composite device provided in the embodiments of this application.

[0023] Reference numerals: 100, diaphragm laminating device; 101, first laminating station; 102, second laminating station; 10, first laminating component; 11, first drive component; 111, cylinder; 112, cam; 12, first support roller; 13, first upper pressure plate; 14, first lower pressure plate; 141, vacuum hole; 15, third drive component; 20, second laminating component; 21, second drive component; 22, movable roller; 23, second support roller; 24, second upper pressure plate; 25, second lower pressure plate; 31, first unwinding structure; 32, second unwinding structure; 201, lower diaphragm; 202, upper diaphragm. Detailed Implementation

[0024] The embodiments of this application are described in detail below with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0025] In the description of this application, it should be understood that the terms "center", "middle", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0026] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] In the description of this application, the use of terms such as "as one implementation," "an embodiment," "some examples," "some embodiments," "illustrative embodiment," "example," "specific example," "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0029] Please see Figures 1 to 3 This application provides a diaphragm lamination device 100, including a first lamination station 101 and a second lamination station 102. The first lamination station 101 is provided with a first driving component 11 and a first lamination component 10. The first driving component 11 drives the first lamination component 10 to press the electrode sheet and the lower diaphragm 201 together. The second lamination station 102 is located downstream of the first lamination station 101 along the feeding direction of the lower diaphragm 201. The second lamination station 102 is provided with a second driving component 21 and a second lamination component 20. The second driving component 21 drives the second lamination component 20 to press the upper diaphragm 202 and the lower diaphragm 201 together. By setting a first composite station 101 and a second composite station 102 in the diaphragm composite device 100, and setting a first composite component 10 and a second composite component 20 respectively, the two composite stations are set sequentially along the feeding direction of the lower diaphragm 201, so that the electrode can be pressed with the lower diaphragm 201 and the upper diaphragm 202 respectively. That is, the electrode is first composited with the lower diaphragm 201, so that the electrode can be fixed on the surface of the lower diaphragm 201 and the electrode and the lower diaphragm 201 can be prevented from shifting relative to each other. Then the upper diaphragm 202 is composited with the lower diaphragm 201. Since the electrode has been initially fixed on the lower diaphragm 201, moving the lower diaphragm 201 or covering the surface of the electrode with the upper diaphragm 202 will not cause the electrode to shift. After the upper diaphragm 202 and the lower diaphragm 201 are laminated, the electrode sheet can be fixed between the upper diaphragm 202 and the lower diaphragm 201 in a preset position. In subsequent processes, the diaphragm is cut to a suitable shape to obtain the laminated electrode sheet. Therefore, the diaphragm lamination device 100 provided in this application can achieve separate lamination of the lower diaphragm 201 and the upper diaphragm 202, and avoid electrode sheet misalignment during this process, thus improving lamination accuracy. Simultaneously, the two lamination stations can operate concurrently, meaning that pressing with the electrode sheet and pressing with the upper diaphragm 202 can be performed simultaneously at different locations on the lower diaphragm 201 material strip, allowing for continuous separate pressing of the electrode sheet with the lower diaphragm 201 and the upper diaphragm 202, thereby improving lamination efficiency.

[0030] For example, the first drive component 11 and the second drive component 21 may be a cylinder 111, an electric cylinder, etc.

[0031] To further address the issue of mutual movement between the electrode and the lower diaphragm 201, in some embodiments, the first composite assembly 10 includes a first lower pressure plate 14. The pressing surface of the first lower pressure plate 14 is provided with vacuum holes 141, which are used to adsorb and fix the lower diaphragm 201 and the electrode. Utilizing the vacuum adsorption effect of the vacuum holes 141, and given the permeable nature of the lower diaphragm 201, the vacuum adsorption force can penetrate the lower diaphragm 201 to adsorb and fix the electrode, thus providing initial fixation for the electrode and the lower diaphragm 201. During the pressing process of the first composite assembly 10, the first lower pressure plate 14 moves upward and comes into contact with the first upper pressure plate 13 to achieve thermo-pressing. Due to the initial fixation of the electrode, electrode displacement can be prevented, thereby enabling the electrode and the lower diaphragm 201 to be pressed together according to a preset position.

[0032] In some embodiments, the composite pressure of the second composite component 20 is greater than that of the first composite component 10. Since the lower diaphragm 201 and the electrode are first pressed together, and then the upper diaphragm 202 and the lower diaphragm 201 need to be pressed together a second time, the composite pressure during the first pressing is sufficient to initially fix the electrode and the lower diaphragm 201. In the second pressing, the upper diaphragm 202, the electrode, and the lower diaphragm 201 need to be completely pressed together and fixed to ensure sufficient connection strength. Therefore, the second composite component 20 is set to have a greater composite pressure to ensure a reliable pressing effect.

[0033] If the distance between the lower diaphragm 201 and the first lower pressure plate 14 is too close during the pressing process, the lower diaphragm 201 will be continuously heated, which will cause the lower diaphragm 201 to shrink and deform. Therefore, in some embodiments, the first composite station 101 is also provided with a first support roller 12. The first support roller 12 is disposed at the inlet of the first composite assembly 10. The first composite assembly 10 includes a first lower pressure plate 14. The support surface of the first support roller 12 is higher than the pressing surface of the first lower pressure plate 14. When the lower diaphragm 201 is wound around the first support roller 12, there is a gap between the lower diaphragm 201 and the pressing surface of the first lower pressure plate 14. By utilizing the support and lifting effect of the first support roller 12 on the lower diaphragm 201 before it enters the first composite component 10, the lower diaphragm 201 can be lifted away and kept at a certain distance from the first lower pressure plate 14, or the distance between the lower diaphragm 201 and the first lower pressure plate 14 can be controlled within a suitable range. This can prevent the lower diaphragm 201 from directly contacting the first lower pressure plate 14 or from being too close, which would cause the lower diaphragm 201 to be heated for too long. This allows the lower diaphragm 201 to be placed in a suitable temperature environment, solving the problem of shrinkage and deformation caused by continuous overheating of the lower diaphragm 201.

[0034] In some embodiments, the first composite assembly 10 includes a first upper pressure plate 13, and a flexible pad is provided on the pressing surface of the first upper pressure plate 13. By providing a flexible pad on the pressing surface of the first upper pressure plate 13, the upper surface of the electrode and the lower diaphragm 201 can be protected during the pressing of the first composite assembly 10, avoiding problems such as scratches on the electrode or diaphragm caused by rigid contact with the first upper pressure plate 13, and ensuring the integrity of the electrode and the lower diaphragm 201 during the pressing process. Exemplarily, the flexible pad can be made of a high-temperature resistant flexible material, such as a silicone sheet.

[0035] In some embodiments, please refer to Figure 3 and Figure 4 The first composite assembly 10 includes a first lower pressure plate 14 and a first drive assembly 11. The first drive assembly 11 includes a cylinder 111 and a cam 112. The cam 112 is connected to the first lower pressure plate 14, and the cylinder 111 is connected to the cam 112 to drive the cam 112 to rotate. The cam 112 is used to drive the first lower pressure plate 14 to rise or fall. Utilizing the driving action of the cylinder 111, combined with the rotational action of the cam 112, the first lower pressure plate 14 can move vertically. When the first lower pressure plate 14 moves upward, the first upper pressure plate 13 can move downward. The first upper pressure plate 13 and the first lower pressure plate 14 can close together to press the electrode sheet and the lower diaphragm 201 together. Optionally, both the first upper pressure plate 13 and the first lower pressure plate 14 can be equipped with structures such as heating tubes and temperature sensors to pressurize and heat the lower diaphragm 201 and the electrode sheet to achieve composite bonding. The first upper pressure plate 13 can be directly driven by the cylinder 111. The output end of the cylinder 111 is connected to the first upper pressure plate 13, so as to realize the movement of the first upper pressure plate 13 in the vertical direction.

[0036] In some embodiments, the first composite assembly 10 includes a first upper pressure plate 13 and a first lower pressure plate 14. The first lower pressure plate 14 is detachably mounted on the first drive assembly 11. The first composite station 101 is also provided with a third drive assembly 15, which drives the first upper pressure plate 13. The first upper pressure plate 13 is detachably mounted on the third drive assembly 15. By setting the first upper pressure plate 13 and the first lower pressure plate 14 as detachable structures, the first upper pressure plate 13 and the first lower pressure plate 14 can be replaced according to different pressing requirements. For example, for electrode composites of different specifications, sizes, and quantities, the corresponding first upper pressure plate 13 and the first lower pressure plate 14 can be replaced, thereby improving the versatility of the first composite assembly 10 and increasing the efficiency of changeover during production. Exemplarily, the third drive assembly 15 can be a cylinder 111.

[0037] After the upper diaphragm 202, lower diaphragm 201, and electrode are pressed together for the second time, the second lower pressure plate 25 of the second composite assembly 20 is prone to sticking to the diaphragm. Therefore, it is necessary to separate the diaphragm from the second lower pressure plate 25. In some embodiments, the second composite station 102 is also provided with a set of movable rollers 22, which includes two movable rollers 22 that are vertically movable. The two movable rollers 22 are respectively positioned at the inlet and outlet of the second composite assembly 20 along the feeding direction of the lower diaphragm 201. The second composite assembly 20 includes a second lower pressure plate 25. The set of movable rollers 22 is used to move upwards after the upper diaphragm 202 and lower diaphragm 201 are pressed together, thereby causing the composite electrode to detach from the second lower pressure plate 25. By utilizing the movable rollers 22 located at the inlet and outlet of the second composite assembly 20, the upward movement of the movable rollers 22 drives the composite electrode sheet upward, thereby separating it from the pressing surface of the second lower pressure plate 25. This facilitates the further transport of the composite electrode sheet away from the second composite assembly 20. This arrangement serves two purposes: firstly, the tension force exerted by the movable rollers 22 on the composite electrode sheet lifts it from the pressing surface, achieving separation between the composite electrode sheet and the second lower pressure plate 25; secondly, the upward movement of the movable rollers 22 continues to provide tension and guidance to the composite electrode sheet, allowing the composite electrode sheet, after lamination, to continue moving away from the second composite assembly 20 and into the next processing station.

[0038] Please see Figure 5In the second composite component 20, there is also a problem where the upper diaphragm 202 is too close to the second upper pressure plate 24 of the second composite component 20, causing the upper diaphragm 202 to be continuously heated and shrink and deform. Therefore, in some embodiments, the second composite station 102 is also provided with a second support roller 23. The second support roller 23 is located at the entrance of the second composite component 20. The second support roller 23 is offset from the movable roller 22. The second composite component 20 includes a second upper pressure plate 24. The supporting surface of the second support roller 23 is lower than the pressing surface of the second upper pressure plate 24. When the upper diaphragm 202 is wound around the second support roller 23, there is a gap between the upper diaphragm 202 and the pressing surface of the second upper pressure plate 24. By utilizing the support of the second support roller 23 before the upper diaphragm 202 enters the second composite assembly 20, the upper diaphragm 202 can be pressed downwards, creating a certain gap between it and the second upper pressure plate 24. Alternatively, the distance between the upper diaphragm 202 and the second upper pressure plate 24 can be controlled within a suitable range. This avoids direct contact between the upper diaphragm 202 and the second upper pressure plate 24, or excessive closeness that could cause the upper diaphragm 202 to be heated for an extended period. Therefore, it helps to set the upper diaphragm 202 in a suitable temperature environment, solving the problem of shrinkage and deformation caused by continuous overheating of the upper diaphragm 202. By staggering the second support roller 23 and the movable roller 22, mutual interference can be avoided, achieving the effect of simultaneously setting the second support roller 23 and the movable roller 22. For example, the movable roller 22 and the second support roller 23 can be staggered in the horizontal or vertical direction.

[0039] In some embodiments, please refer to Figure 6 The diaphragm laminating device 100 further includes a first unwinding structure 31 for providing the lower diaphragm 201 and a second unwinding structure 32 for providing the upper diaphragm 202. Both the first unwinding structure 31 and the second unwinding structure 32 are disposed at the first laminating station 101. The first unwinding structure 31 is located below the first laminating assembly 10 and is used to provide the lower diaphragm 201. The second unwinding structure 32 is located below the first laminating assembly 10. By providing the second unwinding structure 32 above and the first unwinding structure 31 below the first laminating device, a continuous and stable supply of material to the upper diaphragm 202 and the lower diaphragm 201 can be achieved, making the structure of the diaphragm laminating device 100 more compact and reasonable.

[0040] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A diaphragm composite device, characterized in that: include The first composite station is equipped with a first driving component and a first composite component. The first driving component drives the first composite component to press the electrode sheet and the lower separator together. The second composite station is located downstream of the first composite station along the feeding direction of the lower diaphragm. The second composite station is equipped with a second driving component and a second composite component. The second driving component drives the second composite component to press the upper diaphragm and the lower diaphragm together.

2. The diaphragm composite device according to claim 1, characterized in that: The composite pressure of the second composite component is greater than that of the first composite component.

3. The diaphragm composite device according to claim 1, characterized in that: The first composite station is also provided with a first support roller. The first support roller is located at the entrance of the first composite component. The first composite component includes a first lower pressure plate. The support surface of the first support roller is higher than the pressing surface of the first lower pressure plate. When the lower diaphragm is wound around the first support roller, there is a gap between the lower diaphragm and the pressing surface of the first lower pressure plate.

4. The diaphragm composite device according to claim 1, characterized in that: The second composite station is also provided with a movable roller group, which includes two movable rollers that are movable in the vertical direction. The two movable rollers are respectively arranged at the inlet and outlet of the second composite component along the feeding direction of the lower diaphragm. The second composite component includes a second lower pressure plate. The movable roller group is used to move upward after the upper diaphragm and the lower diaphragm are pressed together, so as to drive the composite electrode sheet to detach from the second lower pressure plate.

5. The diaphragm composite device according to claim 4, characterized in that: The second composite station is also provided with a second support roller. The second support roller is located at the entrance of the second composite component. The second support roller is offset from the movable roller. The second composite component includes a second upper pressure plate. The support surface of the second support roller is lower than the pressing surface of the second upper pressure plate. When the upper diaphragm is wound around the second support roller, there is a gap between the upper diaphragm and the pressing surface of the second upper pressure plate.

6. The diaphragm composite device according to claim 1, characterized in that: The first composite component includes a first pressure plate, and the pressing surface of the first pressure plate is provided with vacuum holes, which are used to adsorb and fix the lower diaphragm and the electrode.

7. The diaphragm composite device according to claim 1, characterized in that: The first composite component includes a first lower pressure plate, and the first drive component includes a cylinder and a cam. The cam is connected to the first lower pressure plate, and the cylinder is connected to the cam to drive the cam to rotate. The cam is used to drive the first lower pressure plate to rise or fall.

8. The diaphragm composite device according to claim 1, characterized in that: The first composite component includes a first upper pressure plate and a first lower pressure plate. The first lower pressure plate is detachably installed on the first drive component. The first composite station is also provided with a third drive component, which drives the first upper pressure plate. The first upper pressure plate is detachably installed on the third drive component.

9. The diaphragm composite device according to any one of claims 1 to 7, characterized in that: The first composite component includes a first upper pressure plate, and the pressing surface of the first upper pressure plate is provided with a flexible pad.

10. The diaphragm composite device according to any one of claims 1 to 8, characterized in that: The diaphragm composite device further includes a first unwinding structure for providing a lower diaphragm and a second unwinding structure for providing an upper diaphragm. Both the first unwinding structure and the second unwinding structure are disposed at the first composite station. The first unwinding structure is disposed below the first composite assembly. The first unwinding structure is used to provide the lower diaphragm, and the second unwinding structure is disposed below the first composite assembly.

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