Reflective grid photovoltaic backboard for photovoltaic module and photovoltaic module

Abstract

The utility model relates to the technical field of photovoltaic backboards, and discloses a reflective grid photovoltaic backboard for a photovoltaic module and the photovoltaic module. The reflective grid photovoltaic backboard comprises a base material layer, a weather-proof layer is arranged on the lower surface of the base material layer, and a transparent functional layer is further arranged on the upper surface of the base material layer; a white grid layer and a black reflective grid layer are sequentially stacked on the upper surface of the transparent functional layer, and grids of the white grid layer and the black reflective grid layer are correspondingly arranged at gap positions of battery pieces of the photovoltaic module. According to the reflective grid photovoltaic backboard, through the laminated design of the white grid layer and the black reflective grid layer, the light reflection capability of the photovoltaic backboard can be further improved, light can be managed more effectively, the illumination area of a battery piece is increased, and the double-sided rate and the photoelectric conversion efficiency are greatly improved; the reflective grid photovoltaic backboard is simpler in structure, low in cost, attractive in appearance and weather-proof, and the long-term stability and reliability of a photovoltaic module can be improved.

Description

Technical Field

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

[0002] With the transformation of the global energy structure and the continuous growth in demand for renewable energy, photovoltaic (PV) technology, as an important source of clean energy, has developed rapidly. As the core component of a PV system, the performance of PV modules directly affects the energy conversion efficiency and lifespan of the entire system. The encapsulation materials of PV modules, especially the PV backsheet, are one of the key factors ensuring the long-term stable operation of PV modules. While traditional PV backsheet materials play an important role in protecting the solar cells and providing mechanical support, they still have shortcomings in visible light reflectivity, photoelectric conversion efficiency, and outdoor weather resistance.

[0003] To overcome the aforementioned shortcomings, existing technologies, such as CN208111464U, provide a black grid solar photovoltaic backsheet that can improve power generation efficiency. This backsheet includes a weather-resistant layer, a first adhesive layer, a substrate layer, a second adhesive layer, a white polyolefin alloy layer, a third adhesive layer, and a black polyolefin alloy layer, stacked sequentially. When this existing black grid solar photovoltaic backsheet is applied to photovoltaic modules, its weather-resistant layer is located on the back surface of the entire photovoltaic module, in contact with the external air, while the black polyolefin alloy layer contacts the solar cells through an encapsulating film. This black grid solar photovoltaic backsheet, by setting the black polyolefin alloy layer into a grid pattern and combining it with the white polyolefin alloy layer, can improve the photoelectric conversion efficiency and visible light reflectivity of the solar photovoltaic module.

[0004] However, the existing black grid solar photovoltaic backsheet still has the following defects: (1) The existing black grid solar photovoltaic backsheet only has a black polyolefin alloy layer set in a grid shape, and the light reflection capability is singular. It can only reflect the visible light that passes through the outside of the black polyolefin alloy layer (that is, the visible light that passes through the front of the photovoltaic module) back to the cell through the white polyolefin alloy layer to improve the utilization rate of the front light. However, since the white polyolefin alloy layer is not grid-shaped, the entire white polyolefin alloy layer is difficult to transmit light. Therefore, the light that passes through the outside of the weather-resistant layer (that is, the visible light that passes through the back of the photovoltaic module) will be directly reflected out of the photovoltaic module by the white polyolefin alloy layer, which will cause the back light to be unable to reach the cell and be utilized by the cell, reducing the back light utilization rate, which is not conducive to the improvement of bifaciality, and thus not conducive to the further improvement of the photoelectric conversion efficiency of the photovoltaic module (especially the bifacial photovoltaic module). (2) The layered structure of the existing black grid solar photovoltaic backsheet is relatively complex, with at least three adhesive layers, which is costly and not conducive to promotion and application. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a reflective grid photovoltaic backsheet and photovoltaic module for photovoltaic modules.

[0006] Based on this, the present invention discloses a reflective grid photovoltaic backsheet for photovoltaic modules, including a substrate layer, a weather-resistant layer provided on the lower surface of the substrate layer, and a transparent functional layer provided on the upper surface of the substrate layer.

[0007] A white mesh layer and a black reflective mesh layer are stacked sequentially on the upper surface of the transparent functional layer. The meshes of the white mesh layer and the black reflective mesh layer are respectively set at the gap positions of the solar cells of the photovoltaic module to reflect the light passing through the gaps back to the solar cells.

[0008] Preferably, the transparent functional layer is a transparent fluorine-containing weather-resistant coating.

[0009] Preferably, the transparent functional layer is a transparent waterproof coating.

[0010] More preferably, the thickness of the transparent functional layer is 4–20 μm.

[0011] Preferably, the black reflective mesh layer is a black reflective fluorine-containing mesh coating with a thickness of 4–30 μm.

[0012] Preferably, the white mesh layer is a white fluorine-containing mesh coating with a thickness of 4–30 μm.

[0013] Preferably, the weather-resistant layer is a transparent weather-resistant layer; the transparent weather-resistant layer is a transparent fluorine-containing weather-resistant coating with a thickness of 4–20 μm.

[0014] Preferably, the substrate layer is a transparent substrate layer.

[0015] More preferably, the transparent substrate layer is a polyethylene terephthalate transparent substrate layer with a thickness of 100-300 μm.

[0016] This utility model also discloses a photovoltaic module, including a photovoltaic front panel, a photovoltaic cell layer and a photovoltaic back panel stacked from top to bottom. The photovoltaic cell layer includes a plurality of cells arranged in sequence, with gaps between adjacent cells. The photovoltaic back panel is a reflective grid photovoltaic back panel for photovoltaic modules as described above in this utility model.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] This reflective grid photovoltaic backsheet features a rational structural design. A black reflective grid layer is stacked on top of a white grid layer, with a transparent functional layer serving as the substrate for the two-layer design. The white grid layer is the primary reflective layer, while the black reflective grid layer acts as an auxiliary reflective layer, further enhancing the light reflection capability of the photovoltaic backsheet. This stacked design further reduces light escape from the front of the photovoltaic module into the gaps between the cells, thus improving front light utilization and photoelectric conversion efficiency. Moreover, since both the white and black reflective grid layers are correspondingly arranged grid-like structures, light entering from the back of the photovoltaic module can pass through the mesh of both layers and be absorbed and utilized by the cells, improving back light utilization and further enhancing the photoelectric conversion efficiency of the photovoltaic module. Therefore, this reflective grid photovoltaic backsheet can more effectively manage light, increasing the illuminated area of ​​the cells and significantly improving bifaciality and photoelectric conversion efficiency.

[0019] Meanwhile, the reflective grid photovoltaic backsheet has a simple manufacturing process, a simpler structure, lower cost, and a beautiful appearance. It combines the functional characteristics of other layers such as the weather-resistant layer, which enhances the weather resistance of the photovoltaic backsheet. In addition, the black reflective grid layer also has the function of absorbing heat and reducing the operating temperature of the photovoltaic module, which helps to improve the long-term stability and reliability of the photovoltaic module. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of a photovoltaic module according to this embodiment.

[0021] Figure 2 This is a schematic diagram of the cross-sectional structure of a reflective grid photovoltaic backsheet for a photovoltaic module according to this embodiment.

[0022] Figure 3 This is a top view of a reflective grid photovoltaic backsheet for a photovoltaic module according to this embodiment.

[0023] Explanation of reference numerals: 1. Photovoltaic front panel; 2. Photovoltaic cell layer; 21. Cell; 22. Void; 3. Encapsulating adhesive layer; 4. Photovoltaic back panel; 41. Black reflective mesh layer; 42. White mesh layer; 43. Transparent functional layer; 44. Substrate layer; 45. Weather-resistant layer. 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] One type of photovoltaic module in this embodiment is shown below. Figure 1The photovoltaic system comprises a photovoltaic front panel 1, a photovoltaic cell layer 2, and a photovoltaic back panel 4, which are stacked sequentially from top to bottom. The photovoltaic front panel 1 and the photovoltaic cell layer 2 are bonded together by an encapsulating adhesive layer 3, and the photovoltaic cell layer 2 and the photovoltaic back panel 4 are also bonded together by an encapsulating adhesive layer 3.

[0027] The photovoltaic cell layer 2 includes a number of cells 21 arranged in sequence; Figure 1 Two solar cells 21 arranged in sequence are shown. In practice, the number of solar cells 21 arranged in sequence can be set to more than two, depending on the requirements. There is a gap 22 between two adjacent solar cells 21, through which some of the light entering the photovoltaic module from the front (i.e., the top) can reach the photovoltaic backsheet 4.

[0028] In order to enable the solar cell 21 to fully absorb and utilize the light passing through the gap 22 from the front of the photovoltaic module, and to enable the solar cell 21 to fully absorb and utilize the light entering the photovoltaic module from the back (i.e., the bottom) of the photovoltaic module, the photovoltaic backplate 4 in this embodiment is a reflective grid photovoltaic backplate for photovoltaic modules. The specific structure of the reflective grid photovoltaic backplate is as follows.

[0029] This embodiment provides a reflective grid photovoltaic backsheet for photovoltaic modules. See [link to relevant documentation]. Figure 2-3 It includes a substrate layer 44, and a weather-resistant layer 45 is provided on the lower surface of the substrate layer 44 to give the reflective grid photovoltaic backsheet good weather resistance and chemical stability, ensure its long-term stability in complex outdoor environments, make it suitable for long-term outdoor use, and thus enhance the environmental adaptability and long-term stability of the photovoltaic module.

[0030] Furthermore, a transparent functional layer 43 is also provided on the upper surface of the substrate layer 44. A white mesh layer 42 is provided on the upper surface of the transparent functional layer 43, and a black reflective mesh layer 41 is provided on the upper surface of the white mesh layer 42. In practice, the black reflective mesh layer 41 is bonded to the lower surface of the photovoltaic cell layer 2 by an encapsulating film. Moreover, the mesh of the white mesh layer 42 and the mesh of the black reflective mesh layer 41 are arranged vertically correspondingly, so that the mesh of the white mesh layer 42 and the mesh of the black reflective mesh layer 41 are both located at the gap 22 of the cell 21. In this way, firstly, the mesh of the white mesh layer 42 and the black reflective mesh layer 41 can reflect the part of the light that passes through the gap 22 from the front of the photovoltaic module back to the cell 21, so that this part of the light can be absorbed and utilized by the cell 21 again, thereby improving the front light utilization rate. Secondly, the structure is reasonably designed. The transparent functional layer 43 is used as the substrate of the two-layer grid layer in the stacked design. On the basis of the white grid layer 42, a black reflective grid layer 41 is also stacked. The white grid layer 42 is the main reflective layer, while the black reflective grid layer 41 is the auxiliary reflective layer. The addition of a reflective layer can further enhance the light reflection capability of the reflective grid photovoltaic back panel. This stacked design can further reduce the light escape in the gap 22 of the cell 21, further improve the front light utilization rate, improve the photoelectric conversion efficiency of the photovoltaic module, and increase its power generation gain. Moreover, the reflective layer can also reduce the light-induced degradation (LID) phenomenon. Thirdly, since both the white grid layer 42 and the black reflective grid layer 41 are grid-like structures, and the grids of the white grid layer 42 and the black reflective grid layer 41 are arranged vertically and vertically, light entering from the back of the photovoltaic module can pass through the meshes of the white grid layer 42 and the black reflective grid layer 41, and then be absorbed and utilized by the solar cell 21. This improves the back light utilization rate and helps to further improve the photoelectric conversion efficiency of the photovoltaic module. Therefore, the reflective grid photovoltaic backsheet of this embodiment can more effectively manage light, increase the illumination area of ​​the solar cell 21, and greatly improve the bifaciality and photoelectric conversion efficiency.

[0031] In addition, the black reflective mesh layer 41 also absorbs heat and reduces the operating temperature of the photovoltaic module, which helps to further improve the long-term stability and reliability of the photovoltaic module. Moreover, the black reflective mesh layer 41 also makes the reflective mesh photovoltaic backsheet appear entirely black, providing an aesthetically pleasing appearance and meeting market demands for product aesthetics. This reflective mesh photovoltaic backsheet has a simple structure, low cost, and is easy to mass-produce.

[0032] The white mesh layer 42 is a white fluorine-containing mesh coating to further improve the weather resistance of the reflective grid photovoltaic backsheet. The thickness of this white mesh layer 42 is 4–30 μm (e.g., 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, or 30 μm). This white mesh layer 42 reduces light escape by reflecting and scattering light, thereby improving photoelectric conversion efficiency.

[0033] The black reflective mesh layer 41 is a black reflective fluorine-containing mesh coating to further improve the weather resistance of the reflective mesh photovoltaic backsheet. Preferably, this black reflective mesh layer 41 is a black high-infrared-reflective fluorine-containing mesh coating, giving it high infrared reflectivity, increasing its reflectivity in the 700nm-1100nm wavelength band to over 55%, thereby further improving the light reflectivity of the reflective mesh photovoltaic backsheet, reducing light escape from the gaps 22 in the solar cells 21, and improving the photoelectric conversion efficiency of the photovoltaic module. The thickness of the black reflective mesh layer 41 is 4–30 μm (e.g., 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, or 30 μm).

[0034] In one example of this embodiment, the transparent functional layer 43 is a transparent fluorine-containing weather-resistant coating to further improve the weather resistance of the reflective grid photovoltaic backsheet. In another example of this embodiment, the transparent functional layer 43 is a transparent waterproof coating to improve the waterproof performance of the reflective grid photovoltaic backsheet, reduce its water vapor transmission rate, and further ensure its stability and reliability for long-term outdoor use. Of course, in other examples, the transparent functional layer 43 can also be configured as a transparent coating with other functions.

[0035] In this embodiment, the thickness of the transparent functional layer 43 is 4 to 20 μm (e.g., 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm or 20 μm).

[0036] In order to allow more light entering from the back of the photovoltaic module to pass through the reflective grid photovoltaic backsheet and be fully absorbed and utilized by the solar cells 21, the substrate layer 44 is preferably a transparent substrate layer to further improve the back light utilization rate.

[0037] Furthermore, the transparent substrate layer is a polyethylene terephthalate (PET) transparent substrate layer, preferably a PET transparent substrate layer with a reflectance of 2-12% in the near-infrared band of 700nm-1100nm. The thickness of this transparent substrate layer is 100-300μm (e.g., 100μm, 150μm, 200μm, 250μm or 300μm).

[0038] In order to allow more light entering from the back of the photovoltaic module to pass through the reflective grid photovoltaic backsheet and be fully absorbed and utilized by the solar cells 21, the weather-resistant layer 45 is preferably a transparent weather-resistant layer to further improve the back light utilization rate.

[0039] Furthermore, the transparent weather-resistant layer is a transparent fluorine-containing weather-resistant coating with a thickness of 4–20 μm (e.g., 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm or 20 μm).

[0040] The reflective grid photovoltaic backsheet described in this embodiment has a high reflectivity in the infrared spectral region (700nm-1100nm), which improves the photoelectric conversion efficiency of single-sided photovoltaic modules using this reflective grid photovoltaic backsheet by more than 1% (absolute value). Moreover, the improvement in photoelectric conversion efficiency is even more significant when the reflective grid photovoltaic backsheet is used in bifacial photovoltaic modules. In addition, the reflective grid photovoltaic backsheet has a simple manufacturing process and low cost, and combined with the functional characteristics of other layers, it further enhances the weather resistance of the reflective grid photovoltaic backsheet and improves the reliability and service life of photovoltaic modules.

[0041] 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.

[0042] 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 light-reflecting grid photovoltaic backsheet for photovoltaic modules, characterized in that, The base material layer is provided with a weather-resistant layer on its lower surface and a transparent functional layer on its upper surface; The upper surface of the transparent functional layer is sequentially provided with a white grid layer and a black light-reflecting grid layer, and the grids of the white grid layer and the black light-reflecting grid layer are arranged in the gap positions of the cell pieces of the photovoltaic module to reflect the light transmitted through the gaps back to the cell pieces; The transparent functional layer is a transparent waterproof coating layer; The base material layer is a transparent base material layer; The black light-reflecting grid layer is a black fluorine-containing grid coating layer capable of reflecting infrared light.

2. The photovoltaic backsheet with reflective grid for photovoltaic module according to claim 1, characterized in that, The thickness of the transparent functional layer is 4-20 μm.

3. The photovoltaic backsheet with reflective grid for photovoltaic modules according to claim 1, characterized in that, The thickness of the black light-reflecting grid layer is 4-30 μm.

4. The photovoltaic backsheet with reflective grid for photovoltaic modules according to claim 1, characterized in that, The white grid layer is a white fluorine-containing grid coating layer, and its thickness is 4-30 μm.

5. The photovoltaic backsheet with reflective grid for photovoltaic modules according to claim 1, wherein, The weather-resistant layer is a transparent weather-resistant layer; the transparent weather-resistant layer is a transparent fluorine-containing weather-resistant coating layer, and its thickness is 4-20 μm.

6. The photovoltaic backsheet with reflective grid for photovoltaic modules according to claim 1, characterized in that, The transparent base material layer is a polyethylene terephthalate transparent base material layer, and its thickness is 100-300 μm.

7. A photovoltaic module, comprising a photovoltaic front sheet, a photovoltaic cell layer and a photovoltaic back sheet which are sequentially stacked from top to bottom, the photovoltaic cell layer comprising a plurality of cell pieces arranged in sequence, and a gap between any two adjacent cell pieces; characterized in that, The photovoltaic backboard is a light-reflecting grid photovoltaic backboard for a photovoltaic module according to any one of claims 1-6.

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