A novel photovoltaic backsheet and photovoltaic module

Abstract

This utility model relates to the field of photovoltaic backsheet technology, and discloses a novel photovoltaic backsheet and photovoltaic module. The novel photovoltaic backsheet includes a transparent substrate; a transparent weather-resistant layer is provided on the lower surface of the transparent substrate; the upper surface of the transparent substrate, from top to bottom, is provided with a black grid layer, a white grid layer, a transparent coating, and a transparent water-blocking layer; the grid cutout areas of the black and white grid layers correspond to the solar cells of the photovoltaic module, while the grid lines correspond to the peripheral gap areas of the solar cells. The transparent water-blocking layer and the transparent weather-resistant layer of this photovoltaic backsheet work together to prevent water vapor penetration, improve weather resistance, and further enhance the stability and reliability of the photovoltaic module for outdoor use; the white and black grid layers work together to reduce light escaping from the peripheral gaps of the solar cells through light reflection and scattering; and the transparent coating, transparent water-blocking layer, transparent substrate, and transparent weather-resistant layer work together to absorb and utilize light transmitted from the back of the photovoltaic backsheet, further improving power generation efficiency.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic backsheet technology, specifically to a novel photovoltaic backsheet and photovoltaic module. Background Technology

[0002] A photovoltaic (PV) backsheet is a crucial component of a solar cell module (also known as a photovoltaic module). Located on the back of the module, its primary function is to protect the solar cells from environmental damage (such as moisture, ultraviolet radiation, and mechanical damage), while also providing electrical insulation and structural support. With the rapid development of photovoltaic technology, PV backsheet technology is also continuously evolving. Therefore, to achieve higher photoelectric conversion efficiency and longer lifespan, higher requirements are being placed on the reflectivity and weather resistance of PV backsheets.

[0003] For example, CN218769568U discloses an infrared reflection-enhanced photovoltaic backsheet and module. This infrared reflection-enhanced photovoltaic backsheet includes a reinforcing substrate layer with a black fluorocarbon weather-resistant layer on its lower surface; an infrared reflection composite layer on its upper surface, comprising a black selective light-reflecting coating and a white high-reflection layer located below the black selective light-reflecting coating; and the reinforcing substrate layer comprising, from top to bottom, an ultra-white polyester film layer, a first adhesive layer, a carbon fiber reinforcing layer, a second adhesive layer, and a semi-permeable polyester film layer stacked sequentially. This infrared reflection-enhanced photovoltaic backsheet possesses excellent light reflection, enhancement, and weather resistance properties, improving the light utilization rate and photoelectric conversion efficiency of the solar cells, and enhancing their cooling effect.

[0004] However, while existing infrared-reflective enhanced photovoltaic backsheets have good light reflectivity, their overall black appearance makes it difficult to utilize sunlight incident or scattered from the back (or lower) surface of the photovoltaic backsheet, resulting in some light loss and hindering further improvements in the light utilization and photoelectric conversion efficiency of photovoltaic modules. Furthermore, these existing infrared-reflective enhanced photovoltaic backsheets have poor water resistance, allowing moisture to easily penetrate from the backsheet into the photovoltaic module, thus affecting the stability and reliability of the photovoltaic module during outdoor use. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a new type of photovoltaic backsheet and photovoltaic module.

[0006] Based on this, the present invention discloses a novel photovoltaic backsheet, comprising a transparent substrate; the lower surface of the transparent substrate is provided with a transparent weather-resistant layer;

[0007] The upper surface of the transparent substrate is provided with a black mesh layer, a white mesh layer and a transparent coating layer stacked from top to bottom, and a transparent water-blocking layer is provided between the transparent coating layer and the transparent substrate.

[0008] The open areas of the black and white grid layers correspond to the arrangement of the solar cells in the photovoltaic module, while the grid lines correspond to the peripheral gap areas of the solar cells.

[0009] Preferably, the transparent water-blocking layer is a water-blocking film, which is bonded to the upper surface of the transparent substrate by an adhesive layer.

[0010] More preferably, the water-blocking membrane is a transparent polyvinyl fluoride water-blocking membrane with a thickness of 10-30 μm.

[0011] More preferably, the adhesive layer is a transparent acrylic polyester polyol adhesive layer with a thickness of 5-10 μm.

[0012] Preferably, the transparent coating is a fluorine-containing coating with a thickness of 4-8 μm.

[0013] Preferably, the mesh cutout areas of the black mesh layer and the mesh cutout areas of the white mesh layer are arranged vertically correspondingly.

[0014] More preferably, the black mesh layer is a black reflective fluorine-containing mesh coating with a thickness of 8-12 μm;

[0015] The white mesh layer is a white fluorine-containing mesh coating with a thickness of 8-12 μm.

[0016] Preferably, the transparent weather-resistant layer is a transparent fluorine-containing weather-resistant coating with a thickness of 8-13 μm.

[0017] Preferably, the transparent substrate is a polyethylene terephthalate substrate with a thickness of 270-290 μm.

[0018] This utility model also discloses a photovoltaic module, comprising a photovoltaic front panel, a first encapsulating film, a battery cell, a second encapsulating film, and a photovoltaic back panel stacked from top to bottom, wherein the photovoltaic back panel is a novel photovoltaic back panel as described above in this utility model.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] This utility model features a novel photovoltaic backsheet structure with a reasonable design. By incorporating a transparent water-blocking layer, it effectively prevents water vapor penetration and reduces water vapor transmission rate. Therefore, the combination of the transparent weather-resistant layer and the transparent water-blocking layer further enhances the stability and reliability of the photovoltaic module for outdoor use. Moreover, the overlapping design of the white and black mesh layers on the upper surface significantly improves light reflectivity. By reducing light incident from above the cells and escaping from the gaps around the cells through light reflection and scattering, it increases the illuminated area of ​​the cells, thereby improving the overall light utilization and power generation efficiency of the photovoltaic module. Furthermore, the combination of the transparent coating, transparent water-blocking layer, transparent substrate, and transparent weather-resistant layer on the lower surface of the white mesh layer enables the photovoltaic module to absorb and utilize sunlight transmitted from the back of the photovoltaic backsheet, further improving the overall light utilization and power generation efficiency of the photovoltaic module. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the cross-sectional structure of a novel photovoltaic backsheet according to this embodiment.

[0022] Figure 2 This is a partially enlarged structural diagram showing the grid stacking of the solar cells and the black and white grid layers in the photovoltaic module of this embodiment.

[0023] The following are the symbol descriptions: 1. Black grid layer; 2. White grid layer; 21. Grid line; 3. Transparent coating; 4. Water-blocking film; 5. Adhesive layer; 6. Transparent substrate; 7. Transparent weather-resistant layer; 8. Battery cell. Detailed Implementation

[0024] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example

[0026] This embodiment presents a novel photovoltaic backsheet, see [link / reference]. Figure 1-2 It includes, from top to bottom, a black grid layer 1, a white grid layer 2, a transparent coating 3, a transparent water-blocking layer, a transparent substrate 6, and a transparent weather-resistant layer 7, stacked sequentially. Furthermore, the grid cutout areas of the black grid layer 1 and the white grid layer 2 correspond to the solar cells 8 of the photovoltaic module, while the grid lines 21 correspond to the peripheral gap areas of the solar cells 8 (e.g.,...). Figure 2 (As shown).

[0027] The novel photovoltaic backsheet of this embodiment has a white grid layer 2 and a black grid layer 1 on the upper surface of the transparent coating 3, which can greatly improve the light reflectivity of the photovoltaic backsheet. Sunlight that enters from above the solar cell 8 and passes through the gap area around the solar cell 8 can be reflected back to the solar cell 8 through the grid lines 21 of the white grid layer 2 and the black grid layer 1 and reabsorbed and utilized by the solar cell 8, thereby greatly improving the light utilization rate and photoelectric conversion efficiency of the photovoltaic module.

[0028] Moreover, the novel photovoltaic backsheet of this embodiment has a transparent water-blocking layer laminated on the upper surface of the transparent substrate 6, which can greatly improve the water-blocking performance of the photovoltaic backsheet to prevent water vapor from penetrating into the interior of the photovoltaic module, thus improving the stability and reliability of the photovoltaic module for outdoor use; furthermore, the novel photovoltaic backsheet also has a transparent coating 3 coated on the upper surface of the transparent water-blocking layer, and is combined with a transparent weather-resistant layer 7 on the lower surface of the transparent substrate 6. Thus, in this novel photovoltaic backsheet, except for the white grid layer 2 and black grid layer 1 on the front (or upper surface), all layers on the back (or lower surface) are transparent layers that transmit light. The mesh cutout areas of the black grid layer 1 and the white grid layer 2 correspond to the solar cells 8 of the photovoltaic module. This also improves the light transmittance of the back of the photovoltaic backsheet, allowing sunlight incident or scattered from the back of the photovoltaic backsheet to pass sequentially through the transparent weather-resistant layer 7, the transparent substrate 6, the transparent water-blocking layer, and the transparent coating 3, before reaching the back of the solar cells 8 through the mesh cutout areas of the white grid layer 2 and the black grid layer 1, and then being absorbed and utilized by the solar cells 8. Therefore, this novel photovoltaic backsheet can further improve the light utilization rate and photoelectric conversion efficiency of the photovoltaic module.

[0029] Meanwhile, the transparent weather-resistant layer 7 also gives this new photovoltaic backsheet excellent weather resistance. Therefore, the combination of the transparent water-blocking layer and the transparent weather-resistant layer 7 further enhances the stability and reliability of photovoltaic modules for long-term outdoor use. In addition, this new photovoltaic backsheet is aesthetically pleasing, meeting market demands for aesthetics.

[0030] The white mesh layer 2 is preferably a white fluorinated mesh coating. In practice, this white fluorinated mesh coating is formed by screen printing using existing white fluorinated paint; the existing white fluorinated paint contains white pigments and fillers (such as white pigments and fillers with excellent light reflection and scattering properties), fluorinated resin, and polyester resin. This white mesh layer 2 is used to provide a preliminary light reflection effect, which reduces light escape from the gap area around the solar cell 8 by reflecting and scattering light, and reflects the light from the gap area around the solar cell 8 back to the solar cell 8, thereby improving the light utilization rate and photoelectric conversion efficiency of the photovoltaic module.

[0031] The black mesh layer 1 is preferably a black reflective fluorinated mesh coating. In practice, this black reflective fluorinated mesh coating is formed by screen printing using existing black reflective fluorinated paint. This existing black reflective fluorinated paint contains pigments and fillers with excellent light reflection properties, fluorocarbon resin, and other matrix resins (such as at least one of polyester resin and epoxy resin). This black reflective fluorinated mesh coating further enhances the light reflection capability of the photovoltaic backsheet, increasing the light reflectivity of the photovoltaic backsheet in the 400nm-1100nm wavelength band to over 70%, and giving the photovoltaic backsheet high reflectivity in the visible and near-infrared bands. This further avoids light loss in the gap area around the solar cells 8, increases the illumination area of ​​the solar cells 8, and thus greatly improves the light utilization rate and photoelectric conversion efficiency of the photovoltaic module. Furthermore, this black reflective fluorinated mesh coating also reflects the heat generated by infrared light, reducing the operating temperature of the photovoltaic module.

[0032] Moreover, both the black reflective fluorinated mesh coating and the white fluorinated mesh coating have good weather resistance, ensuring their stability and reliability in complex outdoor environments.

[0033] Although a thicker film layer results in higher light reflectivity, excessively thick film layers also increase costs and decrease cost-effectiveness. Therefore, the thickness of both the black mesh layer 1 and the white mesh layer 2 is preferably 8-12 μm (e.g., 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm), as this film thickness range represents the optimal cost-effectiveness range for light reflectivity.

[0034] The cutout areas of the black grid layer 1 and the white grid layer 2 are vertically aligned. During the actual printing process, it is essential to ensure that the grids of black grid layer 1 and white grid layer 2 completely overlap to guarantee perfect vertical alignment of their cutout areas. Furthermore, both white grid layer 2 and black grid layer 1 can be formed using specially customized screen printing plates to meet the needs of different customers.

[0035] The transparent coating 3 is preferably a fluorinated coating, and its thickness is preferably 4-8 μm (e.g., 4 μm, 5 μm, 6 μm, 7 μm or 8 μm). In practice, the fluorinated coating is made using existing fluorinated coatings; these existing fluorinated coatings mainly contain fluorocarbon resins, polyester resins and other additives, so that the fluorinated coating has excellent weather resistance and visible light transmittance.

[0036] The transparent water-blocking layer is preferably a water-blocking film 4, which is bonded to the upper surface of the transparent substrate 6 by an adhesive layer 5. Specifically, the water-blocking film 4 is preferably a transparent polyvinyl fluoride (PVF) water-blocking film 4, and its thickness is preferably 10-30μm (e.g., 10μm, 15μm, 20μm, 25μm or 30μm) to achieve excellent water-blocking effect, so as to prevent water vapor from penetrating into the interior of the photovoltaic module and improve the stability and reliability of the photovoltaic module for outdoor use.

[0037] The adhesive layer 5 is preferably a transparent acrylic polyester polyol adhesive layer, with a thickness of 5-10 μm (e.g., 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm). The main function of the acrylic polyester polyol adhesive layer is to bond the transparent substrate 6 to the PVF transparent water-blocking film 4, ensuring that the composite interface is free of bubbles and impurities, and that the composite is smooth, so as to proceed to the next coating process.

[0038] The transparent substrate 6 is preferably a transparent polyethylene terephthalate (PET) substrate, and its thickness is preferably 270-290 μm (e.g., 270 μm, 275 μm, 280 μm, 285 μm or 290 μm).

[0039] In practice, to improve interlayer adhesion and composite stability, the surfaces of the transparent substrate 6 and the water-blocking film 4 can be pre-treated with corona discharge.

[0040] The transparent weather-resistant layer 7 is preferably a transparent fluorinated weather-resistant coating, and its thickness is preferably 8-13 μm (more preferably 9-12 μm). In practice, the transparent fluorinated weather-resistant coating is made using existing transparent fluorinated weather-resistant paints; the transparent fluorinated weather-resistant paint also contains other matrix resins (such as at least one of polyvinyl fluoride, acrylic resin, polyester resin, and epoxy resin) to give the transparent fluorinated weather-resistant coating excellent weather resistance and visible light transmittance.

[0041] In this embodiment of the novel photovoltaic backsheet, the black grid layer 1 and white grid layer 2 are not printed across the entire surface. Furthermore, the aforementioned transparent coating 3, transparent water-blocking film 4, adhesive layer 5, transparent substrate 6, and transparent weather-resistant layer 7 all possess excellent transparency and visible light transmittance. Therefore, the unprinted grid areas are transparent areas, corresponding to the solar cells 8. This allows sunlight incident or scattered from the back of the photovoltaic backsheet to pass sequentially through the transparent weather-resistant layer 7, transparent substrate 6, transparent water-blocking layer, and transparent coating 3 before reaching the solar cells 8 through the grid openings. This enables the photovoltaic module to absorb and utilize sunlight incident or scattered from the back of the photovoltaic backsheet, thereby further improving the overall power generation efficiency of the photovoltaic module. This novel photovoltaic backsheet combines excellent light reflectivity, light transmittance, water resistance, weather resistance, and lightweight properties, making it particularly suitable for crystalline silicon or thin-film solar cell modules.

[0042] The novel photovoltaic backsheet of this embodiment has a reasonable structural design. By composited with a water-blocking membrane 4, it can better prevent water vapor penetration and reduce the water vapor transmission rate of the photovoltaic backsheet to ≤0.5g / m³. 2 Day (e.g., 0.3g / m) 2 The overlapping printing of the white grid layer 2 and black grid layer 1 on the upper surface greatly improves the light reflectivity. By reducing the light incident from above the cell 8 and escaping from the gaps around the cell 8 through light reflection and scattering, the illumination area of ​​the cell 8 is increased, thereby improving the overall power generation efficiency of the photovoltaic module. Furthermore, the combination of the transparent coating 3, transparent water-blocking film 4, transparent adhesive layer 5, transparent substrate 6, and transparent weather-resistant layer 7 on the lower surface of the white grid layer 2 enables the photovoltaic module to absorb and utilize sunlight incident or scattered from the back of the photovoltaic backsheet, thereby further improving the overall power generation efficiency of the photovoltaic module.

[0043] A photovoltaic module according to this embodiment includes a photovoltaic front panel, a first encapsulating film, solar cells 8, a second encapsulating film, and a photovoltaic backsheet stacked sequentially from top to bottom. The photovoltaic backsheet is a novel photovoltaic backsheet as described above in this embodiment; wherein, the black grid layer 1 of the novel photovoltaic backsheet is bonded to the lower surface of the solar cells 8 through the second encapsulating film. In practice, the photovoltaic module has several solar cells 8, which are connected in series and / or in parallel, and each solar cell 8 has a gap area around its periphery, thus there is also a gap area between adjacent solar cells 8; the grid lines 21 of the black grid layer 1 and the white grid layer 2 correspond precisely to the gap areas around the solar cells 8 (e.g., ...). Figure 2 (as shown), so that light incident from above the solar cell 8 and escaping from the gap area around the solar cell 8 is reflected back to the solar cell 8 and then reabsorbed and utilized by the solar cell 8.

[0044] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0045] The technical solution provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A novel photovoltaic backsheet, characterized in that, Includes a transparent substrate; the lower surface of the transparent substrate is provided with a transparent weather-resistant layer; The upper surface of the transparent substrate is provided with a black mesh layer, a white mesh layer and a transparent coating layer stacked from top to bottom, and a transparent water-blocking layer is provided between the transparent coating layer and the transparent substrate. The open areas of the black and white grid layers correspond to the arrangement of the solar cells in the photovoltaic module, while the grid lines correspond to the peripheral gap areas of the solar cells.

2. The novel photovoltaic backsheet according to claim 1, characterized in that, The transparent water-blocking layer is a water-blocking film, which is bonded to the upper surface of the transparent substrate by an adhesive layer.

3. A novel photovoltaic backsheet according to claim 2, characterized in that, The water-blocking membrane is a transparent polyvinyl fluoride water-blocking membrane with a thickness of 10-30 μm.

4. A novel photovoltaic backsheet according to claim 2, characterized in that, The adhesive layer is a transparent acrylic polyester polyol adhesive layer with a thickness of 5-10 μm.

5. A novel photovoltaic backsheet according to claim 1, characterized in that, The transparent coating is a fluorine-containing coating with a thickness of 4-8 μm.

6. A novel photovoltaic backsheet according to claim 1, characterized in that, The openwork areas of the black mesh layer and the openwork areas of the white mesh layer are arranged vertically and vertically respectively.

7. A novel photovoltaic backsheet according to claim 1 or 6, characterized in that, The black mesh layer is a black reflective fluorine-containing mesh coating with a thickness of 8-12 μm; The white mesh layer is a white fluorine-containing mesh coating with a thickness of 8-12 μm.

8. A novel photovoltaic backsheet according to claim 1, characterized in that, The transparent weather-resistant layer is a transparent fluorine-containing weather-resistant coating with a thickness of 8-13 μm.

9. A novel photovoltaic backsheet according to claim 1, characterized in that, The transparent substrate is a polyethylene terephthalate substrate with a thickness of 270-290 μm.

10. A photovoltaic module, comprising a photovoltaic front panel, a first encapsulating film, solar cells, a second encapsulating film, and a photovoltaic back panel stacked sequentially from top to bottom, characterized in that, The photovoltaic backsheet is a novel photovoltaic backsheet as described in any one of claims 1-9.

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