Adhesive film structure and back contact solar cell module
By embedding arrayed EVA particles into the POE film, the white spot problem in laser welding of back-contact solar cell modules was solved, maintaining the film's high water resistance and anti-PID performance, and achieving efficient welding of the modules.
Patent Information
- Application Number
- CN202422739621.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2034-11-11
AI Technical Summary
During the laser whole-panel welding process of back-contact solar cell modules, white spots appear at the corresponding positions of the POE film and the laser welding points, affecting the appearance of the modules, and the high water-blocking properties and anti-PID performance of the POE film are not effectively retained.
EVA particles arranged in an array are embedded in the POE film. The top surface of the EVA particles is flush with the POE substrate and does not penetrate the substrate. Combined with the correspondence between the EVA particles and the welding points, the battery cell welding is completed by laser welding.
It solves the white spot problem in laser welding while maintaining the high water barrier and anti-PID performance of the POE film, ensuring that the overall performance of the component is not affected.
Smart Images
Figure CN223463267U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of solar energy manufacturing, in particular to a film structure and a back contact solar cell module. BACKGROUND
[0002] Back contact (BC) solar cells are attracting more and more attention due to their good photoelectric conversion performance. Since the positive and negative electrodes of the back contact solar cell are both on the back surface of the cell, when the back contact solar cell is connected in series into a cell string using the traditional string welding process, the cell string is prone to warping. Therefore, in the current research and development process route exploration of the back contact solar cell module, laser whole plate welding has become the current focus of research due to its low welding stress and low warping characteristics.
[0003] The main process steps of laser whole plate welding include: placing a front encapsulation film on a cover plate glass, then arranging the back contact solar cell pieces on the front encapsulation film according to a predetermined layout, then laying a solder strip on the cell pieces and using laser to weld. Currently, poly(ethylene-1-octene) (POE) film is widely used in solar cell modules due to its good waterproof and potential induced degradation (PID) resistance.
[0004] However, when POE film is used as a front film in the above laser whole plate welding process, white spots will appear at the positions corresponding to the laser welding points of the POE film. SUMMARY
[0005] To overcome the defects of the prior art, the present application provides a film structure and a back contact solar cell module, which can embed a plurality of EVA particles arranged in an array in the film, thereby maintaining the high water resistance of conventional POE film as a whole, ensuring low water vapor transmission rate at the edges, and ensuring that the whole has the high volume resistivity characteristic of POE. When applied to the laser whole plate welding process of the back contact solar cell module, the film structure can reduce or eliminate the occurrence of irreparable white spot defects caused by high temperature during welding of the cell pieces.
[0006] To achieve the above purpose, the present application adopts the following technical solutions:
[0007] In one aspect, the present application provides a film structure comprising a POE substrate;
[0008] The POE substrate has a plurality of EVA particles embedded therein, and the plurality of EVA particles are arranged in an array;
[0009] The top surface of the EVA particles is flush with the upper surface of the POE substrate.
[0010] The bottom surface of the EVA particles opposite to the top surface does not penetrate the POE substrate.
[0011] Further, the application provides a film structure, wherein the thickness of the POE substrate is between 300-600 μm.
[0012] Further, the application provides a film structure, wherein the cross-sectional area of the EVA particles parallel to the surface of the POE substrate gradually decreases along the thickness direction of the POE substrate.
[0013] Further, the application provides a film structure, wherein the EVA particles are semi-spherical, and the bottom surface of the semi-spherical shape serves as the top surface.
[0014] Further, the application provides a film structure, wherein the radius of the EVA particles is between 60% and 90% of the thickness of the POE substrate.
[0015] In another aspect, the application also provides a back contact solar cell module, comprising a cover glass, a front film, a cell piece, a back film and a back plate, wherein the front film of the back contact solar cell module has the film structure of any one of the above.
[0016] Further, the application provides a back contact solar cell module, wherein the array of EVA particles in the front film corresponds to the soldering points on the cell piece.
[0017] Further, the application provides a back contact solar cell module, wherein the top area of the EVA particles is not less than the area of the corresponding soldering points.
[0018] The application has the following advantages:
[0019] The application discloses a film structure, comprising a POE substrate; a plurality of EVA particles arranged in an array are embedded in the POE substrate; the top surface of the EVA particles is flush with the upper surface of the POE substrate; and the bottom surface of the EVA particles opposite to the top surface does not penetrate the POE substrate. When the film is used to prepare a back contact solar cell module, the EVA particles in the film correspond to the positions of the soldering points of the back contact solar cell, and then the soldering of the soldering ribbons and the cell piece is completed by laser. The EVA film does not have the problem of white spots in the laser whole-plate soldering process, so the film provided by the application not only retains the high water resistance of the POE film, ensures the low water vapor transmission rate of the edge, and has the PID resistance performance, but also solves the problem of white spots at the corresponding positions of the front film and the soldering points of the back contact solar cell piece in the laser whole-plate soldering process. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 Structure diagram of the application of the adhesive film structure in the embodiment;
[0021] Figure 2 Structure diagram of the application of the adhesive film structure in the embodiment;
[0022] Figure 3 Structure diagram of the manufacturing equipment of the adhesive film structure in the embodiment;
[0023] Figure 4 Structure diagram of the manufacturing method of the adhesive film structure in the embodiment;
[0024] Figure 5 Structure of the back contact solar cell module in the embodiment.
[0025] Label explanation:
[0026] Adhesive film structure 10; POE substrate 101; upper surface 1011; EVA particle array 102; top surface 1021; EVA particle 103;
[0027] Extrusion direction of the molten POE adhesive film 11; rotation direction of the cooling roller 12; rotation direction of the EVA carrier roller / cooling roller 13;
[0028] Adhesive film manufacturing equipment 20; extrusion die 201; EVA dispensing head 202; cooling roller 203; EVA carrier roller / cooling roller 204; molten POE adhesive film 205;
[0029] Back contact solar cell module 30; cover plate glass 31; front adhesive film 32; cell piece 33; back adhesive film 34; back plate 35; solder joint 36; solder strip 37. DETAILED DESCRIPTION
[0030] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.
[0031] In the current research and development process of back contact solar cell module 30, laser whole plate welding becomes the current focus of research due to its low welding stress and low warping characteristics. The main process steps of laser whole plate welding include: placing the front encapsulation film on the cover plate glass, then arranging the back contact solar cell pieces on the front encapsulation film according to the preset pattern, then laying the solder strip on the cell pieces and using laser welding. At present, POE film is widely used in solar cell modules due to its good waterproof and anti-PID performance. However, when POE film is used as the front film in the above laser whole plate welding process, white spots will appear at the position corresponding to the laser welding point of the POE film, affecting the overall appearance of the solar cell module. However, using EVA (Polyethylene vinyl acetate, ethylene-vinyl acetate copolymer) film will not cause the above white spot problem. One possible reason for this phenomenon is that during the laser welding process, the laser irradiates the solder point position of the back contact solar cell piece to melt the solder on the surface of the solder strip and complete the welding of the solder strip and the cell piece. During this process, the heat generated is conducted to the film below the cell piece through the cell piece. Since the polarity of the POE film is relatively low, the additives in the POE film are more likely to precipitate, resulting in white spots at the position corresponding to the solder point. The polarity of the EVA film is relatively high, and the additives in the EVA film are not easy to precipitate. However, the water vapor transmission rate of the EVA film is relatively high, and the water resistance and anti-PID performance of the EVA film are lower than those of the POE film. Based on the characteristics of POE film and EVA film, the present application provides a film structure that retains the high water resistance and anti-PID performance of POE film while solving the white spot problem during laser welding.
[0032] In one aspect, the present application provides a film structure 10, comprising a POE substrate 101; a plurality of EVA particles 103 are embedded in the POE substrate 101, and the EVA particles 103 are arranged in an array; the top surface 1021 of the EVA particles 103 is flush with the upper surface 1011 of the POE substrate 101; and the bottom surface of the EVA particles 103 opposite to the top surface 1021 does not penetrate the POE substrate 101.
[0033] Specifically, referring to Figure 1As shown, the adhesive film structure 10 of the present application is composed of a POE substrate 101 and EVA particles 103 embedded in the POE substrate 101, wherein the EVA particles 103 are arranged in an array to form an EVA particle array 102. Moreover, the portion of the EVA particle array 102 exposed outside the POE substrate 101 is planar, and thus the portion of the EVA particle array 102 exposed outside the POE substrate 101 forms a plane 1021 which is flush with the upper surface 1011 of the POE substrate 101. Meanwhile, the height of the EVA particles 103 embedded in the POE substrate 101 (i.e. the maximum distance of the EVA particles from the upper surface 1011 of the POE substrate 101) is less than the thickness of the POE substrate 101. In the present embodiment, the shape of the EVA particles 103 is not limited, as long as the portion of the EVA particles exposed on the upper surface 1011 of the POE substrate 101 is planar, and the portion of the EVA particles embedded in the POE substrate 101 is not limited.
[0034] Therefore, the present application provides an adhesive film structure, which comprises a POE substrate 101; a plurality of EVA particles 103 embedded in the POE substrate 101 to form an EVA particle array 102 arranged in an array; a top surface 1021 of the EVA particles 103 flush with an upper surface 1011 of the POE substrate 101; and a bottom surface of the EVA particles 103 opposite to the top surface 1021 does not penetrate the POE substrate 101.
[0035] When the adhesive film provided by the present application is used to prepare a back contact solar cell module 30, the EVA particles 103 in the adhesive film are made to correspond to the positions of the soldering points of the back contact solar cell, and then the soldering of the solder ribbons and the cell pieces is completed by laser. As described above, the EVA adhesive film does not have the problem of white spots in the laser whole-plate soldering process, and thus the adhesive film provided by the present application not only retains the high water resistance of the POE adhesive film, ensures the low water vapor transmission rate of the edge, and has the PID resistance performance, but also solves the problem of white spots at the corresponding positions of the front adhesive film and the soldering points of the back contact solar cell pieces in the laser whole-plate soldering process.
[0036] It can be understood that the specific arrangement of the EVA particles 103 in the POE substrate 101 is related to the layout of the cell pieces and the distribution of the soldering points on the cell pieces in the back contact solar cell module 30. In one possible implementation, in the whole back contact solar cell module 30, each soldering point corresponds to one EVA particle 103.
[0037] Further, the present application provides an adhesive film structure 10, wherein the thickness of the POE substrate 101 is between 300-600 μm, for example, can be 350 μm, 400 μm, 450 μm, 500 μm, 500 μm, etc.
[0038] Further, the present application provides a kind of adhesive film structure 10, wherein, in the thickness direction along POE substrate 101, the cross-sectional area of EVA particle 103 parallel to POE substrate 101 surface gradually decreases.Detailedly, the cross-sectional shape of EVA particle 103 in the thickness direction of POE substrate 101 can be inverted trapezoidal, inverted triangular, semicircular, semi-elliptical, etc..In this way, close to solar cell module, the side of EVA particle with larger cross-sectional area is close to cell piece, which can increase the corresponding area of EVA, prevent POE substrate part from appearing white spot;The side of EVA particle with smaller cross-sectional area is close to cover glass, that is, as close as possible to cover glass side to reduce EVA, prevent water vapor from entering.
[0039] Of course, those skilled in the art can understand that, in the thickness direction along POE substrate 101, the cross-sectional area of EVA particle 103 parallel to POE substrate 101 surface can remain unchanged, that is, the cross-sectional shape of EVA particle 103 in the thickness direction of POE substrate 101 is square or rectangular.
[0040] Further, the present application provides an adhesive film structure 10, wherein EVA particle 103 is hemispherical, and the bottom surface of the hemisphere serves as the top surface, which can also be understood as that the cross-sectional shape of EVA particle 103 in the thickness direction of POE substrate 101 is semicircular.
[0041] Further, the present application provides an adhesive film structure 10, wherein the height dimension of EVA particle 103 in the thickness direction of the adhesive film can be 60% to 90% of the thickness of POE substrate 101, such as 65%, 70%, 75%, 80%, 85%, etc.When EVA particle 103 is hemispherical, the radius of EVA particle 103 is between 60% and 90% of the thickness of POE substrate 101.
[0042] The adhesive film structure of the present application can be produced by the following method. Figure 3 and Figure 4As shown, the novel film structure 10 in the present application is manufactured by a novel film manufacturing device 20, which includes an extrusion die 201, an EVA dispensing head 202, a cooling roller 203, and an EVA carrier roller / cooling roller 204. The extrusion die 201 is used to extrude a molten POE film 205. The EVA dispensing head 206 is used to extrude EVA in granular form, which is adhered to the EVA carrier roller / cooling roller 204. The EVA carrier roller / cooling roller 204 is used to cool the granular EVA, making it hard, and then rotating (the direction of rotation is indicated by 13 in the drawing) with the EVA carrier roller / cooling roller 204. The molten POE film 205 extruded by the extrusion die 201 (the direction of extrusion is indicated by 11 in the drawing) enters the gap between the cooling roller 203 and the EVA carrier roller / cooling roller 204. By adjusting the distance between the rotating cooling roller 203 (the direction of rotation is indicated by 12 in the drawing) and the EVA carrier roller / cooling roller 204, the thickness of the molten POE film 205 can be controlled. During the rotation of the EVA carrier roller / cooling roller 204, the cooled and hardened EVA granules 103 are pressed into the molten POE film 205 and adhered thereto. When the molten POE film 205 leaves the cooling roller 203 and the EVA carrier roller / cooling roller 204, the EVA granules are stripped from the EVA carrier roller / cooling roller 204, forming the novel film structure 10 of the POE substrate with an array of EVA granules 102 of the present application.
[0043] In another aspect, the present application also provides a back contact solar cell module 30, which includes a cover glass 31, a front film 32, a cell sheet 33, a back film 34, and a back plate 35. The front film 32 of the back contact solar cell module 30 adopts the film structure 10 described above.
[0044] Referring to Figure 5 As shown, the back contact solar cell module 30 includes the cover glass 31, the front film 32, the cell sheet 33, the back film 34, and the back plate 35 arranged in layers. In addition, when the front film 32 is arranged, the side of the EVA granule array 102 with the exposed part, i.e., the top surface 1021, is in contact with the cell sheet 33. The front encapsulation structure 31 can be glass, and the back plate 35 can be glass or a TPT back plate. The back film 34 can be an EVA film or a POE film.
[0045] Further, the present application provides a back contact solar cell module 30, in which the EVA granule array 102 in the front film 32 corresponds to the soldering points 36 on the cell sheet 33.
[0046] In order to better eliminate the problem of laying welding ribbon 37 on the battery cell and using laser welding, when the laser high temperature is transmitted through the battery cell to the adhesive film below, when the adhesive film is POE adhesive film, white spots will appear at the laser welding point. When EVA adhesive film is used, there will be no white spots. Therefore, refer to Figure 2 As shown, the laser welding method is to match the EVA particles 103 in the EVA particle array 102 in the adhesive film structure of the present application with the welding points 36 on the battery cell 33. Thus, the white spots in the front adhesive film 32 are reduced or eliminated.
[0047] Combine Figures 3-4 The method for manufacturing the novel adhesive film structure 10 is shown. A strip of EVA dispensing heads 206 is disposed above the EVA carrier roller / cooling roller 204 to extrude dot-shaped EVA particles. The strip of EVA dispensing heads 206 can perform multiple dispensing operations simultaneously, producing a row of EVA particles 103 on the surface of the EVA carrier roller / cooling roller 204. The longitudinal spacing between the EVA particles 103 is controlled by setting the spacing between each dispensing head in the strip of EVA dispensing heads 206, thereby adapting to the longitudinal spacing of the welding points 36 on the battery cell 33. Taking into account the rotation speed of the EVA carrier roller / cooling roller 204, by controlling the gluing frequency of the EVA dispensing head 206, the lateral distance between two adjacent EVA particles 103 can be controlled to match the lateral spacing design distance of the welding points 36 of the battery cell 33, thereby achieving the correspondence between the EVA particles 103 in the front adhesive film 32 and the welding points 36 on the installed battery cell 33, thereby better eliminating the white spots generated on the front adhesive film 32 when welding the welding points 36 on the battery cell 33.
[0048] Furthermore, the present application provides a back-contact solar cell assembly 30 , wherein the top area of the EVA particles 103 is not less than the area of the corresponding welding points 36 .
[0049] Specifically, the top surface of EVA particles 103 directly corresponds to welding points 36 on the cell, directly absorbing the heat generated by laser welding during the welding process. Therefore, by ensuring that the top surface of EVA particles 103 is no smaller than the area of welding points 36, heat absorption can be improved, preventing the generation of white spots due to heat absorption by POE substrate 101. For example, the area of the top surface of EVA particles 103 is 105% to 110% of the area of welding points 36.
[0050] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.
Claims
1. An adhesive film structure, characterized by, The POE substrate comprises a plurality of EVA particles embedded therein, the plurality of EVA particles being arranged in an array; a top surface of the EVA particles is flush with an upper surface of the POE substrate; a bottom surface of the EVA particles opposite to the top surface does not penetrate the POE substrate. The POE substrate has a thickness of 300-600 μm.
2. The film structure of claim 1, wherein, In a thickness direction of the POE substrate, a cross-sectional area of the EVA particles parallel to a surface of the POE substrate gradually decreases.
3. The film structure according to any one of claims 1-2, wherein, The EVA particles are semi-spherical, and a bottom surface of the semi-spherical shape serves as the top surface.
4. The film structure of claim 3, wherein, A radius of the EVA particles is between 60% and 90% of the thickness of the POE substrate.
5. The film structure of claim 4, wherein, The front-side adhesive film has the film structure of any one of claims 1-4.
6. A back contact solar cell module comprising a cover glass, a front adhesive film, a cell sheet, a back adhesive film and a back sheet, characterized in that, The array of the EVA particles in the front-side adhesive film corresponds to the soldering points on the battery piece.
7. The back contact solar cell module according to claim 6, wherein A top area of the EVA particles is not less than an area of the soldering points corresponding thereto.
8. The back contact solar cell module according to claim 7, wherein,