Photovoltaic photo-thermal device and system capable of comprehensively utilizing solar energy

Abstract

The utility model relates to the technical field of comprehensive utilization of solar energy, in particular to a photovoltaic photo-thermal device and system for comprehensively utilizing solar energy, which comprises a semitransparent photovoltaic cell, plane mirror glass and a back photovoltaic cell which are sequentially arranged from top to bottom. According to the structure, sunlight can be fully absorbed and utilized through the semitransparent photovoltaic cell, the photoelectric conversion of ultraviolet light and visible light is excellent, precise reflection of infrared light can be further achieved through plane mirror glass, and efficient conversion of photo-thermal energy is promoted. Besides, the back photovoltaic cell arranged below the plane mirror glass can directly absorb direct light, ground reflected light and environment scattered light which are not utilized on the surface of the plane mirror glass, and sufficient collection and conversion of residual light energy are achieved. The defects of spectrum utilization, efficiency improvement, structure optimization and the like in the prior art are overcome, and an efficient and economical solution is provided for a solar comprehensive utilization system.

Description

Technical Field

[0001] This utility model relates to the field of solar energy comprehensive utilization technology, and in particular to a photovoltaic and photothermal device and system for comprehensive utilization of solar energy. Background Technology

[0002] Solar energy, as a clean and renewable energy source, is of great significance for promoting energy structure transformation and reducing carbon emissions. Currently, solar energy utilization technologies are mainly divided into two categories: photovoltaic technology and solar thermal technology. Each has its own characteristics and utilizes solar energy through the photoelectric effect and thermal energy conversion, respectively.

[0003] Photovoltaic technology relies on the photoelectric effect of photovoltaic cells to directly convert solar energy into electrical energy. However, photovoltaic cells mainly absorb the visible and near-infrared portions of the solar spectrum, and their utilization efficiency for long-wavelength infrared light is limited. In contrast, solar thermal technology uses solar energy to heat the working fluid, converting solar energy into heat energy. It has a particularly good absorption effect on infrared light, but it cannot convert short-wavelength visible and ultraviolet light.

[0004] The solar spectrum covers a wide wavelength range from ultraviolet to infrared. Neither photovoltaic nor photothermal technologies alone can maximize the utilization of solar spectral energy, resulting in limitations in overall energy conversion efficiency. To address this issue, photovoltaic-photothermal coupling technology has emerged, aiming to achieve efficient and comprehensive utilization of the solar spectrum by combining photovoltaic and photothermal systems.

[0005] Although various photovoltaic-thermal coupling methods exist, such as simple mechanical integration (e.g., directly attaching photovoltaic cells to a solar thermal system) or spectral separation via spectrometers, these methods still face numerous challenges in practical applications. First, spectral utilization is insufficient, failing to fully cover all wavelengths of the solar spectrum. Second, increased optical losses reduce energy conversion efficiency. Third, the system structure becomes more complex, increasing construction and maintenance costs.

[0006] In addition, scattered light from the natural environment and sunlight reflected from the ground are also significant components of solar radiation, accounting for a considerable proportion. However, most existing photovoltaic-thermal coupled power plants have low or even completely ignore the utilization efficiency of this portion of solar energy, resulting in a large waste of solar energy resources. This not only further reduces the overall energy conversion efficiency of the system but also fails to fully realize the potential advantages of solar energy technology in resource utilization.

[0007] Therefore, effectively capturing and utilizing ambient light and ground-reflected light has become a key research direction for improving the performance of photovoltaic-thermal coupled power plants. To achieve comprehensive and efficient utilization of solar energy resources, developing a novel photovoltaic-thermal integrated structure that can fully utilize the solar spectrum and improve energy conversion efficiency has become an urgent need to overcome existing technological bottlenecks and further promote the development of solar energy utilization technology.

[0008] In view of this, this utility model is proposed. Utility Model Content

[0009] The purpose of this invention is to provide a photovoltaic and photothermal device and system that comprehensively utilizes solar energy. This photovoltaic and photothermal device improves the utilization rate and energy conversion efficiency of the solar energy spectrum, and solves the shortcomings of existing technologies in terms of spectrum utilization, efficiency improvement, and structural optimization.

[0010] In a first aspect, this utility model provides a photovoltaic and photothermal device that comprehensively utilizes solar energy, comprising a semi-transparent photovoltaic cell, a flat reflective glass, and a back photovoltaic cell arranged sequentially from top to bottom, wherein the back photovoltaic cell 3 includes any one of silicon solar cells, perovskite solar cells, cadmium telluride solar cells, gallium arsenide solar cells, organic solar cells, quantum dot solar cells, and copper indium gallium selenide solar cells.

[0011] As a preferred embodiment of this technical solution, the surface of the back photovoltaic cell is coated with a light-harvesting layer, and the material of the light-harvesting layer includes any one of conjugated polymers, fullerenes and their derivatives, zinc oxide and titanium dioxide.

[0012] As a preferred embodiment of this technical solution, the surface of the light absorption layer of the back photovoltaic cell is provided with a nano-light trap structure, and the surface of the nano-light trap structure is coated with a metamaterial coating.

[0013] The nano-light trap structure includes any one or more of nanopillar arrays, nanocone structures, and nanopore arrays;

[0014] The material of the metamaterial coating includes any one of metal nanoparticles and titanium dioxide-doped metal nanoparticles.

[0015] As a preferred embodiment of this technical solution, a transparent nano-metal mesh electrode is disposed on the glass substrate of the back photovoltaic cell.

[0016] As a preferred embodiment of this technical solution, the semi-transparent photovoltaic cell includes any one of semi-transparent perovskite solar cells, semi-transparent organic solar cells, and semi-transparent quantum dot solar cells.

[0017] As a preferred embodiment of this technical solution, it includes a first encapsulation layer, a semi-transparent photovoltaic cell, a flat reflective glass, a back photovoltaic cell, and a second encapsulation layer arranged sequentially from top to bottom.

[0018] As a preferred embodiment of this technical solution, it includes, from top to bottom, a first encapsulation layer, a first transparent electrode, an electron transport layer, a light absorption layer, a hole transport layer, a second transparent electrode, a planar reflective glass, a reflective coating, a carrier substrate, a back photovoltaic cell, and a second encapsulation layer.

[0019] In a preferred embodiment of this technical solution, a first interface modification layer is disposed between the first transparent electrode and the electron transport layer, a second interface modification layer is disposed between the electron transport layer and the light absorption layer, a third interface modification layer is disposed between the light absorption layer and the hole transport layer, and a fourth interface modification layer is disposed between the hole transport layer and the second transparent electrode.

[0020] In a preferred embodiment of this technical solution, a first antireflective layer is disposed between the first encapsulation layer and the first transparent electrode.

[0021] A second antireflective layer is provided between the second transparent electrode and the planar reflective glass.

[0022] As a preferred embodiment of this technical solution, the second antireflective layer includes a high refractive index layer and / or a low refractive index layer, wherein the material of the high refractive index layer includes any one or more of titanium dioxide and silicon nitride, and the material of the low refractive index layer includes any one or more of silicon dioxide and magnesium fluoride.

[0023] Secondly, this utility model also discloses a photovoltaic and solar thermal system that integrates the above-mentioned photovoltaic and solar thermal devices for the comprehensive utilization of solar energy. For example, a tower solar thermal power plant or a plate solar thermal power plant that includes the above-mentioned photovoltaic and solar thermal devices should also fall within the protection scope of this utility model.

[0024] This utility model, a photovoltaic and solar thermal device that comprehensively utilizes solar energy, has at least the following beneficial effects:

[0025] This photovoltaic-thermal device comprises, from top to bottom, a semi-transparent photovoltaic cell, a flat reflector glass, and a back photovoltaic cell. This structure not only enables full absorption and utilization of sunlight through the semi-transparent photovoltaic cell, exhibiting excellent performance in photoelectric conversion of ultraviolet and visible light, but also utilizes the flat reflector glass to achieve precise reflection of infrared light, promoting efficient conversion of photothermal energy. Furthermore, the back photovoltaic cell, positioned below the flat reflector glass, directly absorbs unused direct sunlight, ground-reflected light, and ambient scattered light from the reflector glass surface, achieving full collection and conversion of residual light energy. Therefore, this photovoltaic-thermal system significantly enhances the adaptability of solar energy systems to complex lighting environments while improving energy utilization efficiency, providing a reliable technical solution for constructing efficient and compact photovoltaic-thermal coupled power plants. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is one of the schematic diagrams of the photovoltaic and photothermal system that comprehensively utilizes solar energy according to this utility model;

[0028] Figure 2 This is the second schematic diagram of the photovoltaic and photothermal system that comprehensively utilizes solar energy according to this utility model;

[0029] Figure 3 This is the third schematic diagram of the photovoltaic and photothermal system that comprehensively utilizes solar energy according to this utility model;

[0030] Figure 4 This is the fourth schematic diagram of the photovoltaic and photothermal system that comprehensively utilizes solar energy according to this utility model;

[0031] Figure 5 This is a schematic diagram of the structure of the second antireflective layer of this utility model;

[0032] Figure 6 This is a schematic diagram of the photovoltaic-thermal system of this utility model applied to a tower-type solar thermal power plant.

[0033] Figure 7 This is a two-dimensional side view of the photovoltaic-thermal system of this utility model applied in a tower-type solar thermal power plant.

[0034] Figure 8 This is a schematic diagram of the photovoltaic-thermal system of this utility model applied to a plate-type solar thermal power plant.

[0035] Figure label:

[0036] 1: Semi-transparent photovoltaic cell; 2: Planar reflective glass; 3: Back photovoltaic cell; 4: First encapsulation layer; 5: Second encapsulation layer; 6: First transparent electrode; 7: Electron transport layer; 8: Light absorption layer; 9: Hole transport layer; 10: Second transparent electrode; 11: Reflective coating; 12: Supporting substrate; 13: First antireflection layer; 14: Second antireflection layer; 15: High refractive index layer; 16: Low refractive index layer; 17: First interface modification layer; 18: Second interface modification layer; 19: Third interface modification layer; 20: Fourth interface modification layer. Detailed Implementation

[0037] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0038] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0040] Example 1

[0041] like Figure 1 As shown, this embodiment provides a photovoltaic-thermal device that comprehensively utilizes solar energy, including a semi-transparent photovoltaic cell 1, a flat reflector glass 2, and a back photovoltaic cell 3 arranged sequentially from top to bottom. The back photovoltaic cell 3 includes any one of silicon solar cells, perovskite solar cells, cadmium telluride solar cells, gallium arsenide solar cells, organic solar cells, quantum dot solar cells, and copper indium gallium selenide solar cells. The opaque photovoltaic cell has a higher energy conversion efficiency than the semi-transparent photovoltaic cell 1. Specifically, the back photovoltaic cell 3 can be connected to the flat reflector glass 2 by means of adhesive, clips, or glass pressing.

[0042] In this embodiment, the semi-transparent photovoltaic cell 1 can be used to absorb visible and ultraviolet light from direct sunlight, while the flat reflector glass 2 is used to reflect the remaining visible, ultraviolet, and all infrared light from direct sunlight passing through the semi-transparent photovoltaic cell 1. The reflected ultraviolet and visible light can be absorbed again by the semi-transparent photovoltaic cell 1 for photoelectric conversion, further improving its energy conversion efficiency. Studies have shown that under standard test conditions, by adding the flat reflector glass 2 below the semi-transparent perovskite solar cell, the conversion efficiency of the semi-transparent perovskite solar cell can be increased from 18% to 21%. Infrared light is precisely reflected onto the solar thermal collector for photothermal conversion. The back photovoltaic cell 3 on the back of the flat reflector glass 2 is used to collect unused direct sunlight, sunlight reflected from the ground, and other ambient light, thereby achieving full collection and conversion of remaining light energy.

[0043] Therefore, this photovoltaic-thermal system can make full use of sunlight, thereby improving the utilization rate and energy conversion efficiency of the solar spectrum of the photovoltaic-thermal system. The utilization rate of the solar spectrum can reach more than 95%, and the energy conversion efficiency can reach 55%, effectively solving the shortcomings of existing technologies in terms of spectrum utilization, efficiency improvement, and structural optimization.

[0044] Specifically, in this embodiment, the semi-transparent photovoltaic cell 1 includes any one of a semi-transparent perovskite solar cell, a semi-transparent organic solar cell, and a semi-transparent quantum dot solar cell.

[0045] Based on the above technical solution, and further preferably, the surface of the back photovoltaic cell 3 can be coated with a light-harvesting layer, which can enhance the absorption capacity of the back photovoltaic cell for scattered and reflected light, and further improve the light energy utilization rate. The materials of the light-harvesting layer include conjugated polymers, fullerenes and their derivatives, zinc oxide, titanium dioxide, a silicon dioxide anti-reflection layer, and inorganic perovskite thin films, etc., and the specific materials can be comprehensively considered according to the specific type of photovoltaic cell, application scenario, and performance requirements.

[0046] Based on the above technical solution, and further preferably, the surface of the light absorption layer of the back photovoltaic cell 3 is provided with a nano-light trap structure. By introducing a nano-light trap structure into the back photovoltaic cell, combined with efficient optical design and advanced materials, the efficiency of multiple reflections and scattering of light can be significantly improved, maximizing the absorption of scattered light and light with low incident angles, thereby improving the overall photoelectric conversion efficiency of the back photovoltaic cell. In addition, the surface of the nano-light trap structure is also coated with a metamaterial coating. The metamaterial coating can achieve low reflectivity and high absorption rate over a wide wavelength range by changing the optical properties of the material surface, thereby enhancing the light trapping effect.

[0047] The nano-light trap structure includes any one or more of nanopillar arrays, nanocone structures, and nanopore arrays;

[0048] The material of the metamaterial coating includes any one of metal nanoparticles and titanium dioxide-doped metal nanoparticles.

[0049] Specifically, periodic nanopillar arrays can enhance light scattering and enhance the absorption of light in specific wavelength bands through surface plasmon resonance. Materials for the nanopillar arrays can include silicon (Si), alumina (Al₂O₃), zinc oxide (ZnO), and silicon nitride (Si₃N₄). The diameter of the nanopillars is typically between 50-200 nm, and the height is between 200-500 nm; the specific dimensions can be optimized according to the target spectrum.

[0050] Nanocone structures can further enhance light-trapping capabilities through gradient refractive indices. Materials suitable for nanocone structures include silicon, cadmium telluride (CdTe), perovskite (MAPbI3), and copper indium gallium selenide (CIGS). Design parameters include a cone base diameter of 100-300 nm, a cone height of 500-800 nm, and a cone density of 50-100 cones per square micrometer.

[0051] Nanopore arrays can absorb light of specific wavelengths through micropore resonance, while reducing light reflection. The materials for nanopore arrays can be transparent conductive materials such as ITO (indium tin oxide), FTO (galvanic tin oxide), and TiO2, with pore sizes of 100-300 nm and periods of 300-500 nm.

[0052] The metamaterial coating is made of metal nanoparticles (silver, gold, aluminum) or titanium dioxide-doped metal nanoparticles. Its thickness is controlled within the range of 50-200 nm, and the specific thickness can be optimized according to the wavelength response of the battery.

[0053] In a specific embodiment of this invention, the preparation method of the nano-light trap structure and the metamaterial coating is as follows:

[0054] (1) Fabrication of nano-light trap structures

[0055] 1. Photolithography

[0056] Nanopatterns are formed on the surface of photovoltaic cells using electron beam lithography or deep ultraviolet (DUV) lithography. The patterns are then transferred to the material surface by etching to form the desired nanopillars, cones, or holes.

[0057] 2. Nanoimprint technology

[0058] Mold imprinting: Using a hard mold with nanostructures, a structure is imprinted on the surface of the material to form a structure.

[0059] Subsequent processing: Dry etching (such as reactive ion etching) is used to improve structural clarity.

[0060] 3. Solution method or self-assembly method

[0061] Nanosphere self-assembly: PS (polystyrene) nanospheres are arranged in a single layer and removed by etching or dissolution to form nanopores.

[0062] Template method: Using an alumina template, the template is removed after the material is filled using chemical deposition technology.

[0063] (2) Coating with metamaterials

[0064] 1. Chemical Vapor Deposition (CVD)

[0065] Precursor gases are introduced into the reaction chamber to grow metamaterial coatings on the battery surface.

[0066] This method is suitable for uniformly coating large-area samples, especially complex surface structures.

[0067] 2. Atomic Layer Deposition (ALD)

[0068] High-precision coating control is achieved through the stepwise growth of molecular layers.

[0069] The advantage of this method is that it can achieve uniform coverage on the surface of nanostructures.

[0070] 3. Solution spin coating method

[0071] A solution containing nanoparticles is spin-coated onto the battery surface and then fixed by heat treatment to form a coating.

[0072] This method is suitable for large-scale, low-cost production.

[0073] Based on the above technical solution, more preferably, a nano-metal mesh transparent electrode is disposed on the glass substrate of the back photovoltaic cell 3. The nano-metal mesh transparent electrode technology can improve the light transmittance and conductivity of the back photovoltaic cell, while optimizing photoelectric performance and structural stability. Furthermore, the mesh structure can minimize light shading and achieve low resistance loss while ensuring high light transmittance.

[0074] Specifically, the transparent nano-metal mesh electrode can be made of the following materials:

[0075] Metallic materials

[0076] Silver (Ag): Excellent electrical conductivity and processability.

[0077] Gold (Au): It has good antioxidant properties and is suitable for special environments.

[0078] Copper (Cu): Low cost and high conductivity, but requires surface passivation to prevent oxidation.

[0079] Composite materials

[0080] Metal oxide doped meshes, such as indium tin oxide (ITO) or aluminum zinc oxide (AZO), provide a certain degree of conductivity while maintaining transparency.

[0081] Metal-graphene composite materials: Utilizing the transparent and conductive properties of graphene, light transmittance is further improved.

[0082] The mesh spacing of the nano-metal mesh transparent electrode is 50-200μm, and the specific choice depends on the balance between transparency and conductivity requirements. The width is 5-20μm to minimize light shading.

[0083] Its shape can be designed as a square, honeycomb, or random grid. Among them, the square grid has good uniformity and is suitable for large-area use; the honeycomb grid has a shorter conductive path and lower resistance; the random grid can avoid interference and improve light transmittance.

[0084] In a specific embodiment of this utility model, the preparation method of the nano-metal mesh transparent electrode includes photolithography, nanoimprinting, and solution methods, etc., and the specific methods are as follows:

[0085] (1) Photolithography

[0086] Coating photoresist onto a glass or flexible substrate;

[0087] The grid pattern is generated using electron beam lithography or deep ultraviolet (DUV) lithography techniques;

[0088] Metal layers are deposited using physical vapor deposition (PVD) or chemical vapor deposition (CVD).

[0089] Solvent cleaning removes the photoresist, forming a metal mesh electrode.

[0090] This method produces highly detailed patterns and allows for precise control of grid spacing and thickness.

[0091] (2) Nanoimprint technology

[0092] Imprinted onto a conductive film using a hard mold with a nano-grid pattern;

[0093] After the mold is released, the grid pattern is transferred to the metal layer using etching technology.

[0094] This method is low-cost and suitable for large-scale manufacturing.

[0095] (3)Solution method

[0096] Prepare solutions containing metal nanoparticles, such as silver nanowires or ITO nanoparticle solutions.

[0097] Apply the solution evenly using spin coating or spray coating methods;

[0098] Heat treatment (100-200℃) or photo-sintering is used to connect the metal particles and form a conductive mesh.

[0099] This method has a simple process and is suitable for flexible substrates and curved battery applications.

[0100] This novel nano-metal mesh transparent electrode achieves an optimal balance between light transmittance and conductivity, providing strong support for the innovation of high-performance photovoltaic cells while meeting the high-efficiency energy utilization requirements of photovoltaic-thermal integrated applications.

[0101] Example 2

[0102] like Figure 2 As shown, this embodiment provides a photovoltaic and solar thermal device that comprehensively utilizes solar energy, including a first encapsulation layer 4, a semi-transparent photovoltaic cell 1, a flat reflector glass 2, a back photovoltaic cell 3, and a second encapsulation layer 5 arranged sequentially from top to bottom.

[0103] The addition of a first encapsulation layer 4 above the semi-transparent photovoltaic cell 1 and a second encapsulation layer 5 below the back photovoltaic cell 3 can effectively improve the mechanical strength and long-term stability of the device.

[0104] Specifically, the materials of the first encapsulation layer 4 and the second encapsulation layer 5 include polyimide, polyethylene, fluoropolymers, etc., with a thickness of 1-10 μm. These materials effectively prevent moisture, dust, and other contaminants from the external environment from entering the photovoltaic thermal system, thereby extending its service life. Simultaneously, they provide mechanical support to ensure the stability of the photovoltaic thermal system during installation and use.

[0105] In existing technologies, photovoltaic and solar thermal technologies utilize the solar spectrum relatively independently, failing to achieve effective division of labor between short-wave (ultraviolet and visible light) and long-wave (infrared light) light. The rear photovoltaic cell 3 of this invention can absorb the remaining direct light, scattered light, and ground-reflected light that are not utilized by the semi-transparent photovoltaic cell 1, thus significantly improving the overall spectral utilization rate of the system.

[0106] Furthermore, traditional solar thermal reflectors cannot fully utilize the direct light and ambient light in the reflected light. In this invention, the back photovoltaic cell 3 is directly arranged on the back of the planar reflector glass 2, which can effectively absorb these unused light energies, thereby reducing the waste of light energy.

[0107] Furthermore, while existing semi-transparent photovoltaic cells 1 can absorb part of the spectrum, they cannot cover the entire effective spectral energy. The introduction of the back photovoltaic cell 3 in this invention enables supplementary utilization of light energy, further improving the overall photoelectric conversion efficiency. Moreover, the back photovoltaic cell 3 uses high-efficiency materials such as silicon solar cells, perovskite solar cells, or copper indium gallium selenide solar cells, ensuring higher energy conversion efficiency.

[0108] In summary, by introducing a back-side photovoltaic cell 3, which works in conjunction with the semi-transparent photovoltaic cell 1 and the photothermal reflector, this invention effectively addresses the shortcomings of existing technologies in terms of spectral utilization, efficiency improvement, and structural optimization, providing an efficient and economical solution for comprehensive solar energy utilization systems.

[0109] Example 3

[0110] like Figure 3 As shown, based on the above embodiments, this embodiment further provides a photovoltaic and solar thermal device that comprehensively utilizes solar energy, including a first encapsulation layer 4, a first transparent electrode 6, an electron transport layer 7, a light absorption layer 8, a hole transport layer 9, a second transparent electrode 10, a plane reflective mirror glass 2, a reflective coating 11, a supporting bottom layer 12, a back photovoltaic cell 3, and a second encapsulation layer 5 arranged sequentially from top to bottom.

[0111] The first transparent electrode 6 is typically made of a material with high light transmittance and high electrical conductivity, such as indium tin oxide (ITO) or zinc oxide (ZnO). The first transparent electrode 6 allows light to penetrate and reach the light-absorbing layer 8, while simultaneously providing an electron channel to rapidly transport photo-excited electrons into the circuit. Furthermore, it can reflect some light, increasing the photocurrent density and thus improving the conversion efficiency of the photovoltaic cell.

[0112] Since the first transparent electrode 6 provides an electron channel to quickly transport electrons generated by photoexcitation into the circuit, in actual use, the first transparent electrode 6 and the electron transport layer 7 can be used individually or in combination.

[0113] The light-absorbing layer 8 is the core component of a photovoltaic cell, directly receiving sunlight and generating electricity. Specifically, the light-absorbing layer 8 absorbs photon energy and excites electrons to transition from the valence band to the conduction band, forming a photocurrent. The choice of its material and its thickness have a significant impact on the conversion efficiency of the photovoltaic-thermal system.

[0114] This invention does not strictly limit the material of the light-absorbing layer 8. For example, it can use perovskite-type organometal halide semiconductors commonly used in semi-transparent perovskite solar cells, organic conjugated molecules commonly used in semi-transparent organic solar cells, or quantum dots commonly used in semi-transparent quantum dot solar cells. The choice of material for the light-absorbing layer 8 allows the semi-transparent photovoltaic cell 1 to achieve high photoelectric conversion efficiency while maintaining a certain level of light transmittance, thereby broadening the application fields of photovoltaic technology.

[0115] The second transparent electrode 10, similar to the first transparent electrode 6, serves to provide hole channels and collect photocurrent. The second transparent electrode 10 ensures that photogenerated holes can be smoothly transported into the circuit and form a closed loop with the external circuit, thereby generating electrical energy.

[0116] Similarly, since the second transparent electrode 10 has the function of providing hole channels and collecting photocurrent, in actual use, the second transparent electrode 10 and the hole transport layer 9 can be used separately or in combination.

[0117] The planar reflector glass 2 of this invention includes float glass, ultra-clear glass, low-iron glass, high-strength tempered glass, etc., and can be further preferably pyramid-shaped glass. Using pyramid-shaped glass as the substrate of the semi-transparent photovoltaic cell 1, the pyramid-shaped structure on its surface can not only improve the adhesion of the photovoltaic cell to the planar reflector glass 2, but also increase the absorption rate of visible light inside the perovskite solar cell in the light absorption layer 8, that is, reduce the transmittance of visible light in the photovoltaic cell, thereby improving the energy conversion efficiency of the photovoltaic cell.

[0118] A reflective coating 11 is disposed on the lower surface of the planar reflective glass 2 to further enhance the light reflection effect. Through the reflective coating 11, more light can be reflected back to the light absorption layer 8, thereby improving the light utilization rate and the conversion efficiency of the semi-transparent photovoltaic cell 1.

[0119] The supporting layer 12 is the supporting structure for the semi-transparent photovoltaic cell 1, used to fix and support the other layers, which ensures the stability and reliability of the semi-transparent photovoltaic cell 1 during installation and use.

[0120] In this embodiment, each layer in the photovoltaic-thermal device plays a different role, working together to ensure the efficient, stable, and reliable operation of the photovoltaic-thermal system.

[0121] Example 4

[0122] like Figure 4-5 As shown, based on the above embodiments, this embodiment further provides a photovoltaic thermal device that comprehensively utilizes solar energy, including, from top to bottom, a first encapsulation layer 4, a first antireflection layer 13, a first transparent electrode 6, a first interface modification layer 17, an electron transport layer 7, a second interface modification layer 18, a light absorption layer 8, a third interface modification layer 19, a hole transport layer 9, a fourth interface modification layer 20, a second transparent electrode 10, a second antireflection layer 14, a plane reflective mirror glass 2, a reflective coating 11, a supporting bottom layer 12, a back photovoltaic cell 3, and a second encapsulation layer 5.

[0123] This embodiment adds a first antireflection layer 13 and a second antireflection layer 14, as well as a first interface modification layer 17, a second interface modification layer 18, a third interface modification layer 19, and a fourth interface modification layer 20, based on embodiment 3. The first antireflection layer 13 is disposed between the first encapsulation layer 4 and the first transparent electrode 6, which can effectively improve the transmittance of sunlight and reduce light reflection loss, thereby improving light absorption efficiency. Specifically, the material of the first antireflection layer 13 includes any one or more of silicon dioxide, magnesium fluoride, and calcium fluoride. The second antireflection layer 14 is disposed between the second transparent electrode 10 and the plane mirror glass 2, mainly used to enhance the light transmittance.

[0124] In this embodiment, the second antireflection layer 14 can be a single-functional layer or a dual-functional layer. The single-functional second antireflection layer 14 is primarily made of one or more of silicon dioxide and magnesium fluoride, with a thickness of 90-150 mm. The dual-functional second antireflection layer 14 primarily comprises a high-refractive-index layer 15 and a low-refractive-index layer 16. The high-refractive-index layer 15 is primarily made of one or more of titanium dioxide and silicon nitride, with a thickness of 250-500 nm. The low-refractive-index layer 16 is primarily made of one or more of silicon dioxide and magnesium fluoride. One or more, with a thickness of 85-185nm, the dual-functional second antireflection layer 14 mainly utilizes the optical interference effect between each layer to enhance the transmission or reflection of light in specific wavelength bands, so as to precisely control the transmission of light in the ultraviolet, visible and infrared bands. Therefore, the setting of the dual-functional second antireflection layer 14 can not only enhance the transmittance of infrared light, but also enhance the reflectance of ultraviolet light and visible light, so that it can be fully absorbed by the upper semi-transparent photovoltaic cell 1, and reduce the damage of ultraviolet light to the lower planar reflector glass 2, so that infrared light is reflected as much as possible.

[0125] In this embodiment, the first interface modification layer 17 is disposed between the first transparent electrode 6 and the electron transport layer 7, mainly used to improve interface matching, promote charge transfer, and reduce interface defects, thereby improving the photoelectric performance of the device; the second interface modification layer 18 is disposed between the electron transport layer 7 and the light absorption layer 8, mainly used to optimize electron transport, reduce interface defects and charge recombination, thereby improving energy conversion efficiency; the third interface modification layer 19 is disposed between the light absorption layer 8 and the hole transport layer 9, mainly used to improve interface charge transport, reduce charge load, and improve energy conversion efficiency; the fourth interface modification layer 20 is disposed between the hole transport layer 9 and the second transparent electrode 10, mainly used to optimize interface contact, reduce charge load loss, improve hole extraction efficiency, and protect the underlying material.

[0126] Example 5

[0127] This embodiment provides a method for preparing the above-mentioned photovoltaic thermal device, including the following steps:

[0128] S1. Select float glass, ultra-clear glass, low-iron glass or high-strength tempered glass as the glass for the plane mirror 2;

[0129] Among them, the plane mirror glass 2 can be further selected as pyramid-shaped glass. Specifically, a pyramid-shaped structure can be prepared on the glass plate by physical or chemical methods. For example, a laser beam can be used to etch the surface of the substrate to form a pyramid-shaped micro-nano structure. The parameters of laser etching (such as power, scanning speed, etching depth, etc.) can be adjusted according to the specific requirements of the pyramid-shaped structure.

[0130] In addition to laser etching, pyramid-shaped structures can also be prepared using methods such as hot melt recrystallization, nanoimprinting, chemical etching (such as hydrofluoric acid and silicate solutions), mechanical grinding, and plasma treatment.

[0131] S2. Preparation of reflective coating 11: One or more layers of high reflectivity materials such as silver, aluminum, copper, gold, chromium, dielectric multilayer film, photonic crystal, and nanostructure thin film are uniformly deposited on the lower surface of the plane mirror glass 2 by magnetron sputtering or vacuum deposition technology. The thickness is preferably 50-300nm.

[0132] S3. Preparation of the supporting substrate 12: A polymer substrate or reinforcing glass fiber is deposited on the surface of the reflective coating 11 by spin coating or spray coating process to enhance the mechanical strength and impact resistance of the plane mirror glass 2. Its thickness is preferably 500μm-2mm.

[0133] S4. Preparation of the second antireflective layer 14: A high refractive index material and a low refractive index material are sequentially deposited on the upper surface of the plane mirror glass 2;

[0134] Among them, for the second antireflection layer 14 of the single-functional layer, silicon dioxide, magnesium fluoride and other materials are prepared on the upper surface of the plane mirror glass 2 by methods such as thermal evaporation, vacuum sputtering and chemical vapor deposition, with a thickness of 90-150nm, in order to enhance the light transmittance.

[0135] For the second antireflective layer 14 of the bifunctional layer, titanium dioxide or silicon nitride is first deposited on the upper surface of the plane mirror glass 2 using methods such as thermal evaporation, electron beam evaporation, or vacuum sputtering to form a high refractive index layer 15 with a thickness of 250nm-500nm. Then, silicon dioxide or magnesium fluoride is deposited to form a low refractive index layer 16 with a thickness of 85nm-185nm. The second antireflective layer 14 of the bifunctional layer can not only enhance the transmittance of infrared light, but also enhance the reflectance of ultraviolet and visible light.

[0136] S5. Preparation of the second transparent electrode 10: Indium tin oxide, fluorine-doped tin oxide or zinc oxide thin film are sputtered on the surface of the second antireflection layer 14 by magnetron sputtering, and then annealed at 200℃-300℃ for 30-60 min to form a second transparent electrode 10 with a thickness of 80-150nm.

[0137] S6. Preparation of the fourth interface modification layer 20: The fourth interface modification layer 20 is prepared on the second transparent electrode 10 by spin coating, slit coating or vacuum thermal evaporation. The interface modification material of the fourth interface modification layer 20 includes any one or more of molybdenum oxide, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate and graphene oxide, and its thickness is 2-10 nm.

[0138] S7. Preparation of hole transport layer 9: A hole transport layer solution is coated on the fourth interface modification layer 20 by spin coating, slit coating or vacuum thermal evaporation to form hole transport layer 9. The hole transport layer solution includes any one or more of nickel oxide, molybdenum oxide, porphyrin self-assembled monolayer, PTAA, two-dimensional graphene and graphene oxide, and its thickness is 20-100 nm.

[0139] S8. Preparation of the third interface modification layer 19: The third interface modification layer 19 is prepared on the hole transport layer 9 by spin coating, slit coating, or vacuum thermal evaporation. The interface modification material of the third interface modification layer 19 includes any one or more of barium titanate, zinc oxide, and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, and its thickness is 2nm-8nm.

[0140] S9. Preparation of light absorption layer 8: The light absorption layer 8 is prepared on the hole transport layer 9 by slit coating, solution method or vapor deposition method. The band gap of the light absorption layer 8 material is 1.70eV-2.30eV, mainly absorbing ultraviolet light and visible light, and its thickness is 300nm-700nm.

[0141] S10. Preparation of the second interface modification layer 18: The second interface modification layer 18 is prepared on the light absorption layer 8 by spin coating, slit coating or vacuum thermal evaporation. The interface modification material of the second interface modification layer 18 includes any one or more of titanium nitride, zinc oxide and [6,6]-phenyl-C61-bucic acid ester, and its thickness is 20nm-50nm.

[0142] S11, Preparation of electron transport layer 7: Electron transport layer 7 is prepared on the second interface modification layer 18 by slit coating or thermal evaporation. The material of electron transport layer 7 includes any one or more of fullerene and its derivatives, zinc oxide and zirconium dioxide, and its thickness is 30-100 nm.

[0143] S12. Preparation of the first interface modification layer 17: The first interface modification layer 17 is prepared on the electron transport layer 7 by spin coating, slit coating, or vacuum thermal evaporation. The interface modification material of the first interface modification layer 17 includes any one or more of aluminum oxide, titanium oxide, and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid, and its thickness is 5nm-10nm.

[0144] S13. Fabrication of the first transparent electrode 6: A multilayer transparent electrode (Au / Ag / MoO) is fabricated on the first interface modification layer 17203 using a magnetron sputtering device. x The material of the first transparent electrode 6 includes any one or more of indium tin oxide, zinc fluoride-doped oxide and tin oxide, and its thickness is 50nm-300nm.

[0145] S14. Preparation of the first antireflection layer 13: Silicon dioxide, magnesium fluoride or calcium fluoride are deposited or coated on the first transparent electrode 6 by chemical vapor deposition, physical vapor deposition or slit coating to prepare the first antireflection layer 13, wherein the thickness of the first antireflection layer 13 is 3nm-10nm.

[0146] S15. Preparation of the first encapsulation layer 4: Polyimide, polyethylene and fluoropolymers and other encapsulation materials are prepared onto the semi-transparent photovoltaic cell 1 by spin coating, blow molding and coating methods. The thickness is 1-10μm. It mainly plays a protective and sealing role to prevent the intrusion of moisture and oxygen and extend the service life of the photovoltaic thermal system.

[0147] S16. Adhere the prepared silicon solar cell, perovskite solar cell, cadmium telluride solar cell, gallium arsenide solar cell, organic solar cell, quantum dot solar cell or copper indium gallium selenide photovoltaic cell to the back of the supporting substrate 12 with adhesive, and ensure the reliability of the adhesion, long-term stability and compatibility between materials.

[0148] Specifically, the following methods can be used:

[0149] Step 1: Preparation

[0150] (1) Clean the surface of the reflector

[0151] Clean the lower surface of the substrate 12 with isopropyl alcohol (IPA) or deionized water to ensure it is free of dust and oil.

[0152] Wipe dry with a lint-free cloth or air dry in a clean environment.

[0153] (2) Inspect the back of the battery

[0154] Ensure that the lower surface of the supporting layer 12 is flat and free of contaminants.

[0155] Based on the battery size, confirm the bonding area and layout.

[0156] Step 2: Glue Selection

[0157] Choose an adhesive with high transparency, low shrinkage, weather resistance, and good bond strength. Examples of suitable adhesive types include:

[0158] 1. Epoxy resin adhesive

[0159] Advantages: High bonding strength, good weather resistance, suitable for environments exposed to sunlight and high temperatures for extended periods.

[0160] 2. UV curing adhesive

[0161] Advantages: Fast curing, suitable for transparent materials, suitable for indoor or UV-lit areas.

[0162] 3. Silicone sealant

[0163] Advantages: High temperature resistance, UV resistance, good elasticity, suitable for environments with thermal expansion and contraction.

[0164] Step 3: Bonding

[0165] (1) Apply glue

[0166] Apply adhesive evenly to the lower surface of the substrate 12, with a recommended thickness of 0.1-0.3 mm, to ensure that air bubbles are eliminated after bonding and that battery performance is not affected. Pay attention to the application area of ​​the adhesive; do not cover the battery electrode area.

[0167] (2) Adhesion to the back photovoltaic cell 3

[0168] Align the back photovoltaic cell 3 with the supporting substrate 12 and gently press to remove excess adhesive and air bubbles. Use clamps or a special mounting bracket to ensure the cell does not slip during bonding.

[0169] (3) Curing adhesive

[0170] Epoxy resin adhesive: Cures at room temperature or heated to 40-60℃. The curing time is adjusted according to the product instructions, generally 12-24 hours.

[0171] UV curing adhesive: Cured under a UV light source with an irradiation intensity of 200-500mW / cm2 and a curing time of 5-10min.

[0172] Silicone sealant: Cures naturally at room temperature, with a curing time of 24-48 hours.

[0173] S17. Preparation of the second encapsulation layer 5: The second encapsulation layer 5 is prepared on the side of the back photovoltaic cell 3 away from the supporting bottom layer 12. The preparation method can refer to the first encapsulation layer 4.

[0174] Example 5

[0175] like Figure 6-8 As shown, the most preferred photovoltaic solar thermal device of this utility model is applied to tower solar thermal power plants and plate solar thermal power plants.

[0176] In tower-type and plate-type solar thermal power plants, the semi-transparent photovoltaic cell 1 is mainly used to absorb visible and ultraviolet light from direct sunlight. The flat reflector glass 2 is used to reflect the remaining visible, ultraviolet, and all infrared light after the direct sunlight passes through the semi-transparent photovoltaic cell 1. The reflected ultraviolet and visible light can be reabsorbed by the semi-transparent photovoltaic cell 1 for photoelectric conversion, while the infrared light is precisely reflected onto the solar thermal collector for photothermal conversion. The back photovoltaic cell 3 on the back of the flat reflector glass 2 is used to collect unused direct sunlight, sunlight reflected from the ground, and other ambient light. Furthermore, the solar tracking system in the solar thermal power plant adjusts the rotation angle to ensure that sunlight enters the photovoltaic thermal device at the optimal angle.

[0177] Studies have shown that applying this novel photovoltaic-thermal device to tower-type and plate-type solar thermal power plants can reduce the overall system's levelized cost of electricity (LCOE) by approximately 10%-25%. Furthermore, the design of this novel photovoltaic-thermal device increases the energy output density per unit area, raising the energy utilization rate to approximately 400W-600W per square meter, making it suitable for large-scale applications. Moreover, the solar thermal system can operate effectively in areas with high radiation intensity (such as areas with direct sunlight exceeding 2000W / m²). 2 Using it in designated areas can further improve photothermal conversion efficiency and reduce operating costs.

[0178] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A photovoltaic-thermal device that comprehensively utilizes solar energy, characterized in that, It includes a semi-transparent photovoltaic cell (1), a flat reflective glass (2), and a back photovoltaic cell (3) arranged sequentially from top to bottom. The back photovoltaic cell (3) includes any one of silicon solar cells, perovskite solar cells, cadmium telluride solar cells, gallium arsenide solar cells, organic solar cells, quantum dot solar cells, and copper indium gallium selenide solar cells.

2. The photovoltaic thermal device according to claim 1, characterized in that, The surface of the back photovoltaic cell (3) is coated with a light-harvesting layer, the material of which includes any one of conjugated polymers, fullerenes and their derivatives, zinc oxide and titanium dioxide.

3. The photovoltaic thermal device according to claim 1, characterized in that, The surface of the light absorption layer of the back photovoltaic cell (3) is provided with a nano-light trap structure, and the surface of the nano-light trap structure is coated with a metamaterial coating.

4. The photovoltaic thermal device according to claim 3, characterized in that, The nano-light trap structure includes any one or more of nanopillar arrays, nanocone structures, and nanopore arrays; The material of the metamaterial coating includes any one of metal nanoparticles and titanium dioxide-doped metal nanoparticles.

5. The photovoltaic thermal device according to claim 1, characterized in that, The back photovoltaic cell (3) has a transparent nano-metal mesh electrode on its glass substrate.

6. The photovoltaic thermal device according to claim 1, characterized in that, The semi-transparent photovoltaic cell (1) includes any one of semi-transparent perovskite solar cells, semi-transparent organic solar cells, and semi-transparent quantum dot solar cells.

7. The photovoltaic thermal device according to claim 1, characterized in that, It includes a first encapsulation layer (4), a semi-transparent photovoltaic cell (1), a flat reflective glass (2), a back photovoltaic cell (3), and a second encapsulation layer (5) arranged sequentially from top to bottom.

8. The photovoltaic thermal device according to claim 1, characterized in that, It includes, from top to bottom, a first encapsulation layer (4), a first transparent electrode (6), an electron transport layer (7), a light absorption layer (8), a hole transport layer (9), a second transparent electrode (10), a plane mirror glass (2), a reflective coating (11), a carrier bottom layer (12), a back photovoltaic cell (3), and a second encapsulation layer (5).

9. The photovoltaic thermal device according to claim 8, characterized in that, A first interface modification layer (17) is provided between the first transparent electrode (6) and the electron transport layer (7), a second interface modification layer (18) is provided between the electron transport layer (7) and the light absorption layer (8), a third interface modification layer (19) is provided between the light absorption layer (8) and the hole transport layer (9), and a fourth interface modification layer (20) is provided between the hole transport layer (9) and the second transparent electrode (10). A first antireflective layer (13) is disposed between the first encapsulation layer (4) and the first transparent electrode (6). A second antireflective layer (14) is provided between the second transparent electrode (10) and the planar reflective glass (2).

10. A photovoltaic-thermal system that comprehensively utilizes solar energy, characterized in that, Includes the photovoltaic thermal device according to any one of claims 1-9.

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