Photovoltaic module

Abstract

The utility model relates to a photovoltaic assembly. The photovoltaic module comprises a battery piece which is provided with a light-facing surface and a backlight surface which are opposite to each other; the back reflection film is arranged on the side close to the backlight face and provided with a plurality of back reflection layers which are sequentially stacked, and the refractive indexes of the back reflection layers are configured to be gradually increased in the direction away from the backlight face. The photovoltaic assembly can effectively reflect sunlight transmitted from the battery piece back to the battery piece, and the photoelectric conversion efficiency of the battery piece is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar energy, in particular to a photovoltaic module. Background Art

[0002] Photovoltaic modules (also known as "solar panels") are the core components of solar power generation systems. Their primary function is to convert solar energy into electricity, which can then be stored or directly used to power loads. PV modules primarily consist of solar cells, encapsulation materials (such as photovoltaic glass and backsheet), encapsulation materials (such as film and frames), and electrical connectors (such as solder ribbons and junction boxes). PV modules offer advantages such as energy conservation, environmental protection, long service life, and low maintenance costs. Consequently, they are widely used in a variety of applications, including photovoltaic power plants, household electricity, traffic lighting, and communications equipment.

[0003] Solar cells are the core components that convert solar energy into electricity. Their conversion efficiency directly impacts the efficiency of solar power generation systems. As production processes continue to evolve, the thickness of solar cells has become increasingly thinner, causing sunlight to easily escape through the cells and be effectively unused, resulting in poor photoelectric conversion efficiency.

[0004] Therefore, this field needs a new technical solution to solve the above problems. Utility Model Content

[0005] To solve or, to a certain extent, improve the technical problem of low photoelectric conversion efficiency of cells in the prior art, the present invention provides a photovoltaic module. The photovoltaic module comprises: a cell having a light-facing surface and a light-reflecting surface opposite each other; and a back reflective film, the back reflective film being arranged on a side proximal to the light-reflecting surface and comprising a plurality of back reflective layers stacked in sequence, wherein the refractive index of the plurality of back reflective layers is configured to gradually increase in a direction away from the light-reflecting surface.

[0006] It will be understood by those skilled in the art that the photovoltaic module of the present invention includes a cell and a back reflective film. The cell has a light-facing surface and a back reflective surface relative to each other. The back reflective film is arranged on the side close to the back reflective surface of the cell. The back reflective film has a plurality of back reflective layers stacked in sequence, and the refractive index of the plurality of back reflective layers is configured to gradually increase in the direction away from the back reflective surface. Therefore, the sunlight transmitted from the cell will not be directly dispersed, but will be blocked by the back reflective film and reflected back to the cell, thereby improving the photoelectric conversion efficiency of the cell. Specifically, when the sunlight passes through each back reflective layer, it will be reflected on its surface and then return to the cell. In addition, after sunlight from different directions passes through the optical effects of multiple back reflection layers, the refractive index of the multiple back reflection layers gradually increases in the direction away from the backlight surface of the cell, so that the propagation direction of most sunlight will tend to be perpendicular to the back reflection film during the process of propagating toward the inside of the back reflection film. The light reflected back to the cell from the back reflection film is more concentrated, thereby ensuring that more sunlight can be reflected back to the cell, further improving the photoelectric conversion efficiency of the cell.

[0007] In the preferred technical solution of the above photovoltaic module, each of the back reflective layers is made of silicon nitride, which has excellent optical properties and chemical stability, ensuring that sunlight is effectively and stably reflected back to the solar cell.

[0008] In the preferred technical solution of the photovoltaic module, the refractive index of each back reflective layer is 1.5-2.5. With the above arrangement, sunlight can be significantly deflected when propagating inside the back reflective layer, thereby ensuring that more sunlight is reflected back to the solar cell.

[0009] In the preferred technical solution of the photovoltaic module, each of the back reflective layers has a thickness of 3 nm to 30 nm, and / or the back reflective film has a thickness of 40 nm to 100 nm. This arrangement allows the back reflective layers and the back reflective film to have a moderate thickness, thereby balancing sunlight reflection requirements and raw material costs.

[0010] In the preferred technical solution of the photovoltaic module, the number of the plurality of back reflection layers is greater than or equal to 3. Through the above configuration, the back reflection layers can have a larger number of layers, so as to more flexibly adjust the propagation path of sunlight.

[0011] In the preferred technical solution of the photovoltaic module, the multiple back reflection layers are formed by a vapor deposition process. This process can achieve excellent performance of the back reflection layer by controlling the deposition temperature, ensuring a thin thickness and excellent uniformity. Furthermore, the process is relatively mature and can also appropriately reduce processing costs.

[0012] In the preferred technical solution of the photovoltaic module, the back reflective film further includes a reflection enhancement layer located on a side of the plurality of back reflective layers away from the backlight surface. The reflection enhancement layer can block sunlight transmitted through the back reflective layers, further improving the photovoltaic conversion efficiency of the cell.

[0013] In the preferred technical solution of the above-mentioned photovoltaic module, the material of the reflection-enhancing layer is silver, aluminum, palladium, silicon carbide, zinc oxide, indium nitride, polycrystalline silicon, titanium dioxide, silicon-containing oxide or indium tin oxide; and / or the thickness of the reflection-enhancing layer is 5nm-20nm; and / or the reflection-enhancing layer is connected to the multiple back reflection layers through a vapor deposition process. By selecting reflection-enhancing layers of different materials, the product types can be enriched to meet the differentiated needs of users. The thickness of the reflection-enhancing layer is set to 5nm-20nm, which can make it have a moderate thickness, thereby taking into account the reflection needs of sunlight and the cost of raw materials. In addition, the reflection-enhancing layer is connected to the back reflection layer using a vapor deposition process, so that the reflection-enhancing layer has good performance.

[0014] In the preferred technical solution of the above-mentioned photovoltaic module, the photovoltaic module further includes: a back-reflective film, the back-reflective film is opposite to the backlight surface; and a back plate, the back plate is arranged on the side of the back-reflective film away from the backlight surface; and the back-reflective film is arranged between the backlight surface and the back-reflective film; and / or the back-reflective film is arranged inside the back-reflective film; and / or the back-reflective film is arranged between the back-reflective film and the back plate; and / or the back-reflective film is arranged inside the back plate. Through the above-mentioned arrangement, the photovoltaic module has the structure of a single-glass module to reduce production costs. In addition, by flexibly adjusting the back-reflective film at different positions of the photovoltaic module, the types of products can be enriched to meet the differentiated needs of users.

[0015] In the preferred technical solution of the above-mentioned photovoltaic module, the photovoltaic module further includes: a back adhesive film, the back adhesive film is opposite to the backlight surface; and a back glass, the back glass is arranged on the side of the back adhesive film away from the backlight surface; and the back reflective film is arranged between the backlight surface and the back adhesive film; and / or the back reflective film is arranged inside the back adhesive film; and / or the back reflective film is arranged between the back adhesive film and the back glass; and / or the back reflective film is arranged inside the back glass. Through the above-mentioned arrangement, the photovoltaic module has the structure of a double-glass module to improve the photoelectric conversion efficiency, heat dissipation performance and structural stability of the battery cell. In addition, by flexibly adjusting the back reflective film at different positions of the photovoltaic module, the types of products can be enriched to meet the differentiated needs of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0017] Figure 1This is a schematic structural diagram of the first embodiment of the photovoltaic assembly of the present utility model;

[0018] Figure 2 This is a schematic structural diagram of a second embodiment of the photovoltaic assembly of the present utility model;

[0019] Figure 3 This is a schematic structural diagram of the first embodiment of the back reflective film in the photovoltaic module of the utility model;

[0020] Figure 4 It is a structural schematic diagram of the second embodiment of the back reflective film in the photovoltaic module of the utility model.

[0021] List of reference numerals:

[0022] 100. Photovoltaic module; 110. Front glass; 120. Front adhesive film; 130. Solar cell; 131. Light-facing surface; 132. Backlight surface; 140. Back-reflective film; 141. Back-reflective layer; 1411. First back-reflective layer; 1412. Second back-reflective layer; 1413. Third back-reflective layer; 1414. Fourth back-reflective layer; 1415. Fifth back-reflective layer; 142. Reflection-enhancing layer; 150. Back adhesive film; 160. Back glass; 170. Junction box; 180. Back panel; 190. Frame. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "front", "back", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0025] Furthermore, it should be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "installed," "set," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0026] To solve or improve to a certain extent the technical problem of poor photoelectric conversion efficiency of a cell 130 in the prior art, the present invention provides a photovoltaic module 100. The photovoltaic module 100 includes: a cell 130 having a light-facing surface 131 and a light-reflecting surface 132 facing each other; and a back reflective film 140 disposed on a side adjacent to the back reflective surface 132 and comprising a plurality of sequentially stacked back reflective layers 141, wherein the refractive index of the plurality of back reflective layers 141 is configured to gradually increase in a direction away from the back reflective surface 132.

[0027] Figure 1 This is a schematic structural diagram of the first embodiment of the photovoltaic module of the present utility model. Figure 1 As shown, in one or more embodiments, the photovoltaic module 100 of the present invention includes components such as a front glass 110, a front adhesive film 120, a cell 130, a back reflective film 140, a back adhesive film 150, a back glass 160, and a junction box 170. In other words, the photovoltaic module 100 has a double-glass structure. In the assembled state, the front glass 110 is located on the outermost side of the photovoltaic module 100, that is, the side facing the sunlight; the back glass 160 is located on the outermost side of the photovoltaic module 100, that is, the side facing away from the sunlight. The front adhesive film 120, the cell 130, the back reflective film 140, and the back adhesive film 150 are sequentially arranged between the front glass 110 and the back glass 160. The junction box 170 is arranged on the back glass 160 and forms an electrical connection with the cell 130, thereby transmitting the electrical energy generated by the cell 130 to a battery or an electrical load.

[0028] like Figure 1 As shown, in one or more embodiments, the front glass 110 is made of tempered glass, so that it has good strength, hardness, wear resistance and impact resistance, so as to play the role of light transmission and protection of internal components. Alternatively, the front glass 110 can also use other suitable glass such as laminated glass, single-sided film glass, etc. to increase its thermal insulation and shock absorption properties, increase light transmittance, and reduce the reflection of sunlight. In one or more embodiments, the thickness of the front glass 110 ranges from 1.6mm to 4mm, so that it has a moderate thickness. Alternatively, the thickness of the front glass 110 can also be adjusted according to actual needs. The light transmittance of the front glass 110 is greater than or equal to 90% to ensure the photoelectric conversion efficiency of the entire photovoltaic module 100.

[0029] like Figure 1As shown, in one or more embodiments, the front film 120 is an EVA film (i.e., Ethylene-vinyl Acetate Copolymer) to separate the front glass 110 and the solar cells 130, providing a certain degree of shock absorption and buffering, thereby enhancing the structural strength and service life of the photovoltaic module 100. Alternatively, the front film 120 may be made of a POE film (i.e., Polyolefin Elastomer), a PVB film (i.e., Polyvin Butaral), an EPE film (i.e., a co-extruded POE film), or other suitable films.

[0030] like Figure 1 As shown, in one or more embodiments, a plurality of cells 130 are arranged spaced apart from each other. The plurality of cells 130 are connected by suitable soldering ribbons (e.g., tinned copper ribbons, etc.) so as to bring together the current generated by each cell 130, thereby forming a larger output current. The cell 130 may be, but is not limited to, a monocrystalline cell, a PERC cell (i.e., Passivated Emitter and Rear Cell), a TOPCon cell (i.e., Tunnel Oxide Passivating Contacts Cell), or an HJT cell (i.e., Hetero-junction with Intrinsic Thin-film Cell). The cell 130 has a light-facing surface 131 and a light-removing surface 132 facing each other. In the assembled state, the light-facing surface 131 faces the sunlight, while the light-removing surface 132 faces away from the sunlight. When sunlight shines on the cell 130, the semiconductor material on the cell 130 will produce a photovoltaic effect, thereby converting light energy into electrical energy.

[0031] like Figure 1 As shown, in one or more embodiments, the backing film 150 is an EVA film (i.e., Ethylene-vinyl Acetate Copolymer) to separate the back glass 160 and the solar cell 130, provide a certain degree of shock absorption and buffering, and enhance the structural strength and service life of the photovoltaic module 100. Alternatively, the backing film 150 may also be a POE film (i.e., Polyolefin Elastomer), a PVB film (i.e., Polyvin Butaral), an EPE film (i.e., a co-extruded POE film), or other suitable films.

[0032] like Figure 1As shown, in one or more embodiments, the back glass 160 is made of tempered glass, so that it has good strength, hardness, wear resistance and impact resistance, so as to play the role of light transmission and protection of internal components. The provision of the back glass 160 can also make the photovoltaic module 100 have a symmetrical structure, ensuring that the front and back sides of the battery cell 130 are evenly stressed, while allowing the photovoltaic module 100 to adopt a frameless design, reducing the possibility of PID (Potential Induced Degradation) attenuation. Alternatively, the back glass 160 can also be made of other suitable glass such as laminated glass and single-sided film glass. In one or more embodiments, the thickness of the back glass 160 ranges from 1.6mm to 4mm. Alternatively, the thickness of the back glass 160 can also be adjusted according to actual needs.

[0033] like Figure 1 As shown, the back reflective film 140 is arranged on the side of the cell 130 close to the backlight surface 132 to block the sunlight transmitted from the cell 130, thereby improving the photoelectric conversion efficiency of the cell 130. In one or more embodiments, the back reflective film 140 is arranged between the backlight surface 132 of the cell 130 and the adhesive film 150, so that the sunlight transmitted from the cell 130 can be promptly blocked by the back reflective film 140 and reflected back to the cell 130. Alternatively, the back reflective film 140 can also be arranged in other suitable locations, such as inside the adhesive film 150, between the adhesive film 150 and the back glass 160, inside the back glass 160, etc. In addition, the back reflective film 140 can also be arranged in multiple locations mentioned above at the same time to further improve the reflection effect.

[0034] Figure 3 This is a schematic structural diagram of the first embodiment of the back reflective film in the photovoltaic module of the present invention. Figure 3 As shown, in one or more embodiments, the back reflection film 140 includes three back reflection layers 141 stacked in sequence, namely a first back reflection layer 1411, a second back reflection layer 1412, and a third back reflection layer 1413. The refractive index of the three back reflection layers 141 is configured to gradually increase along the direction away from the backlight surface 132 of the cell 130. In one or more embodiments, the material of each back reflection layer 141 is silicon nitride, which has excellent optical properties and chemical stability, ensuring that sunlight is effectively and stably reflected back to the cell 130. In one or more embodiments, the refractive index of each back reflection layer 141 is 1.5-2.5. For example, the refractive index of the first back reflection layer 1411 is 1.5, the refractive index of the second back reflection layer 1412 is 2.0, and the refractive index of the third back reflection layer 1413 is 2.5.

[0035] Continue to see Figure 3When sunlight transmitted from the cell 130 hits the back reflective film 140, part of the sunlight will be reflected from the surface of each back reflective layer 1411 and return to the cell 130. Another part of the sunlight will enter the first back reflective layer 1411, the second back reflective layer 1412, and the third back reflective layer 1413 in sequence, and be refracted on the surfaces of adjacent back reflective layers 141. Since the refractive index of the multiple back reflective layers 141 gradually increases in the direction away from the backlight surface 132 of the cell 130, light from different directions will be more concentratedly reflected back to the cell 130 after passing through the optical effect of the back reflective film 140, so that more sunlight can be reflected back to the cell 130, thereby significantly improving the photoelectric conversion efficiency of the cell 130.

[0036] In various embodiments, each back reflection layer 141 has a thickness of 3 nm to 30 nm, achieving a moderate thickness that balances sunlight reflection requirements with raw material costs. In various embodiments, the entire back reflection film 140 has a thickness of 40 nm to 100 nm, achieving a moderate thickness. Alternatively, the number of back reflection layers 141 may be set to any other suitable number, greater or less than three, such as two, four, or five. Preferably, the number of back reflection layers 141 is greater than or equal to three to allow for more flexible adjustment of the sunlight propagation path.

[0037] In one or more embodiments, the plurality of back reflection layers 141 are processed by a vapor deposition process to accurately process a thickness that meets the design requirements and to make it have good uniformity. The vapor deposition process can be, but is not limited to, chemical vapor deposition (i.e., Chemical Vapor Deposition, abbreviated as CVD) or physical vapor deposition (i.e., Physical Vapor Deposition, abbreviated as PVD). Alternatively, the plurality of back reflection layers 141 can also be processed by other suitable processes. It should be noted that the refractive index of each back reflection layer 141 can be changed by adjusting the gas flow ratio of vapor deposition, the deposition temperature, or by ultraviolet light irradiation to meet the design requirements.

[0038] Figure 4 This is a schematic structural diagram of the second embodiment of the back reflective film in the photovoltaic module of the present invention. Figure 4As shown, in one or more embodiments, the back reflection film 140 includes five back reflection layers 141 stacked in sequence, namely, a first back reflection layer 1411, a second back reflection layer 1412, a third back reflection layer 1413, a fourth back reflection layer 1414, and a fifth back reflection layer 1415. The refractive index of these five back reflection layers 141 is configured to gradually increase in a direction away from the backlight surface 132 of the cell 130. The back reflection film 140 also includes a reflection enhancement layer 142 located on the side of the five back reflection layers 141 away from the backlight surface 132 of the cell 130. The provision of the reflection enhancement layer 142 can block sunlight transmitted through the back reflection layers 141, further improving the photoelectric conversion efficiency of the cell 130. The material of the reflection enhancement layer 142 can be, but is not limited to, silver, aluminum, palladium, silicon carbide, zinc oxide, indium nitride, polycrystalline silicon, titanium dioxide, silicon-containing oxides, or indium tin oxide. Silicon-containing oxides include, but are not limited to, silicon dioxide and silicon oxynitride. In one or more embodiments, the thickness of the reflection enhancement layer 142 is 5 nm to 20 nm, which is a moderate thickness to balance the solar reflection requirements and the raw material cost. The reflection enhancement layer 142 can be connected to the back reflection layer 141 by vapor deposition or other suitable processes.

[0039] Figure 2 This is a schematic structural diagram of the second embodiment of the photovoltaic module of the present utility model. Figure 2 As shown, in one or more embodiments, the photovoltaic module 100 of the present invention includes components such as a front glass 110, a front adhesive film 120, a cell 130, a back adhesive film 150, a back reflective film 140, a back sheet 180, a junction box 170, and a frame 190. In other words, the photovoltaic module 100 has the structure of a single-glass module. In the assembled state, the front glass 110 is located on the outermost side of the photovoltaic module 100, i.e., the side facing the sunlight; the back sheet 180 is located on the outermost side of the photovoltaic module 100, i.e., the side facing away from the sunlight; the front adhesive film 120, the cell 130, the back adhesive film 150, and the back reflective film 140 are sequentially arranged between the front glass 110 and the back sheet 180. The junction box 170 is arranged on the back sheet 180 and forms an electrical connection with the cell 130, thereby transmitting the electrical energy generated by the cell 130 to a battery or an electrical load.

[0040] like Figure 2 As shown, in one or more embodiments, the backsheet 180 is a TPT film, which is a polyethyleneimide film with a surface coating of a special polyamide resin, resulting in excellent mechanical properties, heat resistance, electrical insulation, and electrical stability. The provision of the backsheet 180 can enhance the structural strength of the entire photovoltaic module 100, provide good support for the cells 130, and effectively prevent foreign matter such as dust, air, and moisture from damaging the cells 130. Alternatively, the backsheet 180 can also be made of other suitable materials, such as PET film, PI film, etc.

[0041] like Figure 2 As shown, in one or more embodiments, the frame 190 can be made of a suitable metal material, such as aluminum alloy, stainless steel, etc., to provide good mechanical strength and structural stability. The provision of the frame 190 can secure the front glass 110, front adhesive film 120, solar cells 130, back adhesive film 150, back reflective film 140, and back plate 180, which are stacked in sequence, together to form a stable structure. In addition, the provision of the frame 190 can also facilitate the securing of the entire photovoltaic module 100 to other components (such as a photovoltaic bracket, etc.).

[0042] like Figure 2 As shown, the back reflective film 140 is disposed on the side of the cell 130 that is adjacent to the backlight surface 132. In one or more embodiments, the back reflective film 140 is disposed between the adhesive film 150 of the cell 130 and the back plate 180. Alternatively, the back reflective film 140 may be disposed in other suitable locations, such as between the backlight surface 132 of the cell 130 and the adhesive film 150, within the adhesive film 150, or within the back plate 180. Furthermore, the back reflective film 140 may be disposed simultaneously in multiple locations to further enhance the reflective effect.

[0043] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A photovoltaic module, characterized in that: The photovoltaic module comprises: A cell having a light-facing surface and a backlight surface facing each other; and A back reflection film is arranged on a side close to the backlight surface and comprises a plurality of back reflection layers stacked in sequence, wherein the refractive index of the plurality of back reflection layers is configured to gradually increase along a direction away from the backlight surface.

2. The photovoltaic module according to claim 1, characterized in that The material of each back reflection layer is silicon nitride.

3. The photovoltaic module according to claim 1, characterized in that The refractive index of each of the back reflection layers is 1.5-2.

5.

4. The photovoltaic module according to claim 1, characterized in that The thickness of each back reflection layer is 3nm-30nm; and / or The thickness of the back reflective film is 40nm-100nm.

5. The photovoltaic module according to claim 1, characterized in that The number of the plurality of back reflection layers is greater than or equal to 3.

6. The photovoltaic module according to claim 1, characterized in that The plurality of back reflection layers are formed by a vapor deposition process.

7. The photovoltaic module according to any one of claims 1 to 6, characterized in that: The back reflection film further includes a reflection enhancement layer located on a side of the plurality of back reflection layers away from the backlight surface.

8. The photovoltaic module according to claim 7, characterized in that: The material of the reflection enhancement layer is silver, aluminum, palladium, silicon carbide, zinc oxide, indium nitride, polysilicon, titanium dioxide, silicon-containing oxide or indium tin oxide; and / or The thickness of the reflection enhancement layer is 5nm-20nm; and / or The reflection enhancing layer is connected to the plurality of back reflection layers through a vapor deposition process.

9. The photovoltaic module according to claim 1, characterized in that: The photovoltaic module further comprises: a backing film, the backing film being opposite to the backlight surface; and a back plate, the back plate being arranged on a side of the adhesive film away from the backlight surface; and The back reflective film is arranged between the backlight surface and the adhesive film; and / or The back reflective film is arranged inside the back adhesive film; and / or The back reflective film is arranged between the back adhesive film and the back plate; and / or The back reflective film is arranged inside the back plate.

10. The photovoltaic module according to claim 1, characterized in that: The photovoltaic module further comprises: a backing film, the backing film being opposite to the backlight surface; and a back glass, the back glass being arranged on a side of the adhesive film away from the backlight surface; and The back reflective film is arranged between the backlight surface and the adhesive film; and / or The back reflective film is arranged inside the back adhesive film; and / or The back reflective film is arranged between the back adhesive film and the back glass; and / or The back reflective film is arranged inside the back glass.

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