Photovoltaic photo-thermal system capable of comprehensively utilizing solar energy and preparation method and application of photovoltaic photo-thermal system

Abstract

The invention relates to the technical field of comprehensive utilization of solar energy, in particular to a photovoltaic photo-thermal system capable of comprehensively utilizing solar energy and a preparation method and application thereof, and the photovoltaic photo-thermal system 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] The present invention relates to the technical field of comprehensive utilization of solar energy, and in particular to a photovoltaic and photothermal system for comprehensive utilization of solar energy, and a preparation method and application thereof. Background Art

[0002] As a clean and renewable energy, the development and utilization of solar energy is of great significance to promoting the transformation of energy structure and reducing carbon emissions. At present, solar energy utilization technology is mainly divided into two categories: photovoltaic technology and photothermal technology. Both have their own characteristics and realize the utilization of 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 light and near-infrared light in the solar spectrum, and have limited efficiency in utilizing long-wavelength infrared light. In contrast, photothermal technology uses solar energy to heat the working fluid and convert solar energy into thermal energy. It has a good absorption effect on infrared light, but cannot convert short-wavelength visible light and ultraviolet light.

[0004] The solar spectrum covers a wide range of wavelengths from ultraviolet to infrared. Photovoltaic or photothermal technology alone cannot maximize the utilization of solar spectrum energy, resulting in limitations in overall energy conversion efficiency. To solve this problem, photovoltaic-photothermal coupling technology came into being, aiming to achieve efficient and comprehensive utilization of the solar spectrum by combining photovoltaic and photothermal systems.

[0005] Although there are many ways to couple photovoltaics with thermal energy, such as simple mechanical integration (e.g. attaching photovoltaic cells directly to the thermal energy system) or separating the spectrum through a spectrometer, these methods still face many challenges in practical applications. First, the spectrum is not fully utilized and fails to fully cover all wavelengths of the solar spectrum; second, optical losses increase, reducing energy conversion efficiency; third, the system structure is complicated, increasing construction and maintenance costs.

[0006] In addition, scattered light in the natural environment and sunlight reflected from the ground are also important parts of solar radiation, accounting for a considerable proportion. However, most existing photovoltaic and solar-thermal coupled power stations have low efficiency in utilizing this part of light energy, or even completely ignore it, resulting in a large amount of solar energy resources being wasted. This not only further reduces the overall energy conversion efficiency of the system, but also fails to give full play to the potential advantages of solar energy technology in resource utilization.

[0007] Therefore, how to effectively capture and utilize ambient light and ground reflected light has become a key research direction for improving the performance of photovoltaic-thermal coupled power stations. In order to achieve comprehensive and efficient utilization of solar energy resources, it is urgent to develop a new photovoltaic-thermal integrated structure that can fully utilize the solar spectrum and improve energy conversion efficiency to break through the existing technical bottleneck and promote the further development of solar energy utilization technology.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The purpose of the present invention is to provide a photovoltaic thermal system that comprehensively utilizes solar energy, and a preparation method and application thereof, which improves the utilization rate of the solar energy spectrum and the energy conversion efficiency, and solves the deficiencies of the prior art in terms of spectrum utilization, efficiency improvement, and structural optimization.

[0010] In a first aspect, the present invention provides a photovoltaic thermal system for comprehensive utilization of solar energy, comprising a semi-transparent photovoltaic cell, a plane reflector glass and a back photovoltaic cell arranged in sequence from top to bottom.

[0011] As a preferred embodiment of the present technical solution, the surface of the back photovoltaic cell is coated with a light capture layer, and the material of the light capture layer includes any one of a conjugated polymer, fullerene and its derivatives, zinc oxide and titanium dioxide.

[0012] As a preferred embodiment of the present technical solution, a nano light trap structure is provided on the surface of the light absorption layer of the rear photovoltaic cell, and a metamaterial coating is coated on the surface of the nano light trap structure;

[0013] The nano light trap structure includes any one or more of a nano column array, a nano cone structure and a nano hole array;

[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 the present technical solution, a nano-metal grid transparent electrode is provided on the glass substrate of the rear photovoltaic cell.

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

[0017] The back photovoltaic cell includes any one of a silicon solar cell, a perovskite solar cell, a cadmium telluride solar cell, a gallium arsenide solar cell, an organic solar cell, a quantum dot solar cell and a copper indium gallium selenide solar cell.

[0018] As a preferred embodiment of the present technical solution, it includes a first encapsulation layer, a semi-transparent photovoltaic cell, a plane reflector glass, a back photovoltaic cell and a second encapsulation layer which are arranged in sequence from top to bottom.

[0019] As a preferred technical solution, it includes a first packaging layer, a first transparent electrode, an electron transport layer, a light absorption layer, a hole transport layer, a second transparent electrode, a plane reflector glass, a reflective coating, a supporting bottom layer, a back photovoltaic cell and a second packaging layer arranged in sequence from top to bottom.

[0020] As a preferred embodiment of the present technical solution, a first interface modification layer is arranged between the first transparent electrode and the electron transport layer, a second interface modification layer is arranged between the electron transport layer and the light absorption layer, a third interface modification layer is arranged between the light absorption layer and the hole transport layer, and a fourth interface modification layer is arranged between the hole transport layer and the second transparent electrode.

[0021] As a preferred embodiment of the present technical solution, a first anti-reflection layer is provided between the first encapsulation layer and the first transparent electrode.

[0022] A second anti-reflection layer is arranged between the second transparent electrode and the plane reflector glass.

[0023] As a preferred embodiment of the present technical solution, the second anti-reflection 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.

[0024] In a second aspect, the present invention further discloses a method for preparing the above photovoltaic thermal system, comprising the following steps:

[0025] S1. Select float glass, ultra-clear glass, low-iron glass or high-strength tempered glass as the plane reflector glass;

[0026] S2, uniformly depositing a high reflectivity material on the lower surface of the plane reflector glass;

[0027] S3, depositing a polymer substrate or reinforcing glass fiber on the surface of the reflective coating;

[0028] S4, sequentially depositing a high refractive index material and a low refractive index material on the upper surface of the plane reflector glass to prepare a second anti-reflection layer;

[0029] S5, sputtering an indium tin oxide, a fluorine-doped tin oxide or a zinc oxide thin film on the surface of the second anti-reflection layer by a magnetron sputtering method to prepare a second transparent electrode;

[0030] S6, preparing a fourth interface modification layer on the second transparent electrode;

[0031] S7, coating a hole transport layer solution on the fourth interface modification layer to form a hole transport layer;

[0032] S8, preparing a third interface modification layer on the hole transport layer;

[0033] S9, preparing a light absorbing layer on the third interface modification layer;

[0034] S10, preparing a second interface modification layer on the light absorbing layer;

[0035] S11, preparing an electron transport layer on the second interface modification layer;

[0036] S12, preparing a first interface modification layer on the electron transport layer;

[0037] S13, preparing one or more transparent electrodes on the first interface modification layer;

[0038] S14, depositing or coating silicon dioxide, magnesium fluoride or calcium fluoride on the first transparent electrode to prepare a first anti-reflection layer;

[0039] S15, preparing a first encapsulation layer on the first anti-reflection layer;

[0040] S16, installing a back photovoltaic cell on a side of the carrier substrate away from the reflective coating;

[0041] S17, preparing a second encapsulation layer on a side of the back photovoltaic cell away from the supporting bottom layer.

[0042] On the third aspect, the application of the photovoltaic thermal system of the present invention in a tower-type thermal power station or a plate-type thermal power station should also fall within the protection scope of the present invention.

[0043] The photovoltaic and thermal system of the present invention comprehensively utilizes solar energy, and has at least the following beneficial effects:

[0044] The photovoltaic thermal system of the present invention includes a semi-transparent photovoltaic cell, a plane reflector glass and a back photovoltaic cell arranged in sequence from top to bottom. This structure can not only fully absorb and utilize sunlight through the semi-transparent photovoltaic cell, and excel in the photoelectric conversion of ultraviolet light and visible light, but can also further utilize the plane photothermal reflector to achieve precise reflection of infrared light, and promote the efficient conversion of photothermal energy. In addition, the back photovoltaic cell arranged below the plane reflector glass of the present invention can directly absorb the unused direct light, ground reflected light and ambient scattered light on the surface of the plane reflector glass, and realize the full collection and conversion of the remaining light energy. Therefore, the photovoltaic thermal system of the present invention significantly enhances the adaptability of the solar energy system to complex lighting environments while improving the energy utilization efficiency, and provides a reliable technical solution for building an efficient and compact photovoltaic thermal coupling power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 This is one of the schematic diagrams of the photovoltaic thermal system for comprehensive utilization of solar energy according to the present invention;

[0047] Figure 2 This is the second schematic diagram of the photovoltaic thermal system for comprehensive utilization of solar energy according to the present invention;

[0048] Figure 3 This is the third schematic diagram of the photovoltaic thermal system for comprehensive utilization of solar energy of the present invention;

[0049] Figure 4 This is the fourth schematic diagram of the photovoltaic thermal system for comprehensive utilization of solar energy of the present invention;

[0050] Figure 5 is a schematic structural diagram of the second anti-reflection layer of the present invention;

[0051] Figure 6 It is a schematic diagram of the application structure of the photovoltaic thermal system of the present invention in a tower-type thermal power station;

[0052] Figure 7 It is a two-dimensional side view of the application structure of the photovoltaic thermal system of the present invention in a tower-type thermal power station;

[0053] Figure 8 It is a schematic diagram of the application structure of the photovoltaic thermal system of the present invention in a plate-type thermal power station.

[0054] Reference numerals:

[0055] 1: semi-transparent photovoltaic cell; 2: plane reflector 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 bottom layer; 13: first anti-reflection layer; 14: second anti-reflection 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 DESCRIPTION

[0056] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0057] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0058] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Example 1

[0060] like Figure 1 As shown, this embodiment provides a photovoltaic thermal system that comprehensively utilizes solar energy, including a semi-transparent photovoltaic cell 1, a plane reflector glass 2 and a back photovoltaic cell 3 arranged in sequence from top to bottom.

[0061] In this embodiment, the semi-transparent photovoltaic cell 1 can be used to absorb visible light and ultraviolet light in direct sunlight, and the plane reflector glass 2 is used to reflect the remaining visible light, ultraviolet light and all infrared light of the direct light passing through the semi-transparent photovoltaic cell 1, wherein the reflected ultraviolet light and visible light can be absorbed by the semi-transparent photovoltaic cell 1 for secondary photoelectric conversion, further improving its energy conversion efficiency. Studies have shown that under standard test conditions, by adding a plane reflector glass 2 under the semi-transparent perovskite solar cell, the conversion efficiency of the semi-transparent perovskite solar cell can be increased from 18% to 21%. The infrared light is accurately reflected to the photothermal collector for photothermal conversion. The back photovoltaic cell 3 on the back of the plane reflector glass 2 is used to collect unused direct light, sunlight reflected from the ground, and other ambient light, thereby achieving full collection and conversion of the remaining light energy.

[0062] Therefore, the photovoltaic thermal system can make full use of sunlight, thereby improving the utilization rate of the solar energy spectrum and the energy conversion efficiency of the photovoltaic thermal system. Among them, the utilization rate of the solar energy spectrum can reach more than 95%, and the energy conversion efficiency can reach 55%, which effectively solves the shortcomings of the existing technology in spectrum utilization, efficiency improvement, and structural optimization.

[0063] 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.

[0064] 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 energy conversion efficiency of opaque photovoltaic cells is higher than that of translucent photovoltaic cells 1. Specifically, the back photovoltaic cell 3 can be connected to the plane reflector glass 2 by gluing, snapping or glass pressing.

[0065] On the basis of the above technical solution, it is further preferred that the surface of the back photovoltaic cell 3 can be coated with a light capture layer, which can enhance the absorption capacity of the back photovoltaic cell for scattered light and reflected light, and further improve the utilization rate of light energy. Among them, the material of the light capture layer includes conjugated polymers, fullerenes and their derivatives, zinc oxide, titanium dioxide, silicon dioxide anti-reflection layer and inorganic perovskite film, etc., which can be comprehensively considered according to the specific type, application scenario and performance requirements of the photovoltaic cell.

[0066] On the basis of the above technical solution, it is further preferred that a nano light trap structure is provided on the surface of the light absorption layer of the back photovoltaic cell 3. By introducing the nano light trap structure into the back photovoltaic cell, combined with efficient optical design and advanced materials, the multiple reflection and scattering efficiency of light can be significantly improved, and the absorption of scattered light and light with low incident angles can be maximized, 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, which can achieve low reflectivity and high absorption rate in a wide band by changing the optical properties of the material surface, thereby enhancing the light trap effect;

[0067] Wherein, the nano light trap structure includes any one or more of a nano column array, a nano cone structure and a nano hole array;

[0068] The material of the metamaterial coating includes any one of metal nanoparticles and titanium dioxide-doped metal nanoparticles.

[0069] Specifically, the periodic nanocolumn array can enhance the scattering of light and enhance the absorption of light in a specific wavelength band through the surface plasmon resonance effect. The material of the nanocolumn array can be silicon (Si), aluminum oxide (Al 2 O 3 )、ZnO、Silicon Nitride 3 N 4 ), etc. The diameter of the nanorod is usually between 50-200nm and the height is 200-500nm. The specific size can be optimized according to the target spectrum.

[0070] The nanocone structure can further enhance the light capture ability by gradient refractive index. The materials of the nanocone structure can be silicon, cadmium telluride (CdTe), perovskite (MAPbI 3 ), copper indium gallium selenide (CIGS), etc. Its design parameters are: cone base diameter is 100-300nm, cone height is 500-800nm, and cone density is 50-100 per square micron.

[0071] Nanohole arrays can absorb light of a specific wavelength through micropore resonance while reducing light reflection. The materials of nanohole arrays can be ITO (indium tin oxide), FTO (gallium tin oxide), TiO 2 Transparent conductive materials such as quartz crystals have a pore size of 100-300nm and a period of 300-500nm.

[0072] The material of the metamaterial coating is metal nanoparticles (silver, gold, aluminum) or titanium dioxide doped metal nanoparticles. Its thickness is controlled within the range of 50-200nm, and the specific thickness can be optimized according to the band response of the battery.

[0073] In a specific embodiment of the present invention, the preparation method of the nano light trap structure and the metamaterial coating is as follows:

[0074] (1) Fabrication of nanostructured light traps

[0075] 1. Photolithography

[0076] Nano-patterns are formed on the surface of photovoltaic cells using electron beam lithography or deep ultraviolet (DUV) lithography, and the patterns are transferred to the surface of the material by etching to form the desired nano-pillars, cones or holes.

[0077] 2. Nanoimprint technology

[0078] Mold imprinting: Use a hard mold with nanostructures to imprint structures on the surface of the material.

[0079] Post-processing: Use dry etching (such as reactive ion etching) to improve structural clarity.

[0080] 3. Solution method or self-assembly method

[0081] Nanosphere self-assembly: PS (polystyrene) nanospheres are arranged in a monolayer and removed by etching or dissolution to form nanopores.

[0082] Template method: Use an alumina template, fill the material using chemical deposition technology, and then remove the template.

[0083] (2) Metamaterial coating

[0084] 1. Chemical vapor deposition (CVD)

[0085] Reaction precursor gases are introduced into the reaction chamber to grow the metamaterial coating on the cell surface.

[0086] This method is suitable for uniformly coating large-area samples, especially surfaces with complex structures.

[0087] 2. Atomic layer deposition (ALD)

[0088] High-precision coating control is achieved through the gradual growth of molecular layers.

[0089] The advantage of this method is that it can achieve uniform coverage on the nanostructure surface.

[0090] 3. Solution spin coating

[0091] The solution containing nanoparticles is spin-coated onto the battery surface and fixed by heat treatment to form a coating.

[0092] This method is suitable for large-scale and low-cost production.

[0093] On the basis of the above technical solution, more preferably, a nano-metal mesh transparent electrode is provided 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 the photoelectric performance and structural stability. In addition, the mesh structure can also minimize light blocking and achieve low resistance loss while ensuring high light transmittance.

[0094] Specifically, the following materials can be selected for the nano metal grid transparent electrode:

[0095] Metal Materials

[0096] Silver (Ag): Excellent conductivity and processability.

[0097] Gold (Au): Good anti-oxidation performance, suitable for special environments.

[0098] Copper (Cu): Low cost, high conductivity, but requires surface passivation to prevent oxidation.

[0099] Composite Materials

[0100] Metal oxide-doped grids, such as indium tin oxide (ITO) or aluminum zinc oxide (AZO), provide a certain degree of conductivity while maintaining transparency.

[0101] Metal-graphene composite materials: Utilize the transparent conductive properties of graphene to further improve light transmittance.

[0102] The grid structure spacing of the nano-metal grid transparent electrode is 50-200μm, and the specific selection depends on the balance between transparency and conductivity requirements. The width is 5-20μm to minimize light blocking.

[0103] 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.

[0104] In a specific embodiment of the present invention, the preparation method of the nano-metal mesh transparent electrode includes photolithography technology, nano-imprint technology and solution method, and the specific method is as follows:

[0105] (1) Photolithography

[0106] Coating photoresist on glass or flexible substrate;

[0107] Generate the grid pattern using electron beam lithography or deep ultraviolet (DUV) lithography;

[0108] Depositing the metal layer by physical vapor deposition (PVD) or chemical vapor deposition (CVD);

[0109] Solvent cleaning removes the photoresist and forms a metal grid electrode.

[0110] This method has high pattern fineness and can precisely control the grid spacing and thickness.

[0111] (2) Nanoimprint technology

[0112] A hard mold with a nano-grid pattern is imprinted on a conductive film;

[0113] After the mold is released, the grid pattern is transferred to the metal layer through etching technology.

[0114] This method has low cost and is suitable for large-area manufacturing.

[0115] (3)Solution method

[0116] Preparing a solution containing metal nanoparticles, such as a silver nanowire or ITO nanoparticle solution;

[0117] The solution is evenly coated by spin coating or spray coating;

[0118] Heat treatment (100-200°C) or photosintering is used to connect the metal particles and form a conductive grid.

[0119] This method is simple in process and suitable for flexible substrate and curved battery applications.

[0120] The nano-metal grid transparent electrode of the present invention can achieve an optimal balance between light transmittance and conductivity, providing strong support for the innovation of high-performance photovoltaic cells, while meeting the demand for efficient energy utilization in photovoltaic and thermal integrated applications.

[0121] Example 2

[0122] like Figure 2 As shown, this embodiment provides a photovoltaic thermal system that comprehensively utilizes solar energy, including a first packaging layer 4, a semi-transparent photovoltaic cell 1, a plane reflector glass 2, a back photovoltaic cell 3 and a second packaging layer 5 arranged in sequence from top to bottom.

[0123] Among them, installing a first encapsulation layer 4 above the semi-transparent photovoltaic cell 1 and installing a second encapsulation layer 5 below the back photovoltaic cell 3 can effectively improve the mechanical strength and long-term stability of the device.

[0124] Specifically, the materials of the first encapsulation layer 4 and the second encapsulation layer 5 include polyimide, polyethylene, fluoropolymer, etc., and the thickness thereof is 1-10 μm, which can effectively prevent moisture, dust and other pollutants in the external environment from entering the photovoltaic thermal system, thereby extending the service life of the photovoltaic thermal system. At the same time, it can also provide certain mechanical support to ensure the stability of the photovoltaic thermal system during installation and use.

[0125] In the prior art, photovoltaic and photothermal technologies are relatively independent in the use of the solar spectrum, and cannot achieve effective division of labor for the use of short waves (ultraviolet and visible light) and long waves (infrared light). The arrangement of the back photovoltaic cell 3 of the present invention can absorb the remaining direct light, scattered light and ground reflected light that are not used by the translucent photovoltaic cell 1, thereby significantly improving the overall spectrum utilization of the system.

[0126] In addition, the conventional photothermal reflector cannot fully utilize the direct light and ambient light in the reflected light. The back photovoltaic cell 3 of the present invention is directly arranged on the back of the plane reflector glass 2, which can effectively absorb the unused light energy, thereby reducing the waste of light energy.

[0127] Furthermore, although the existing semi-transparent photovoltaic cell 1 can absorb part of the spectrum, it is difficult to cover all the effective spectrum energy. The introduction of the back photovoltaic cell 3 of the present invention realizes the supplementary utilization of light energy and further improves the overall photoelectric conversion efficiency. The back photovoltaic cell 3 uses high-efficiency materials such as silicon solar cells, perovskite solar cells or copper indium gallium selenide solar cells to ensure higher energy conversion.

[0128] In summary, the present invention introduces the back photovoltaic cell 3, which works in coordination with the semi-transparent photovoltaic cell 1 and the photothermal reflector, effectively solving the deficiencies of the prior art in terms of spectrum utilization, efficiency improvement, and structural optimization, and provides an efficient and economical solution for the comprehensive utilization system of solar energy.

[0129] Example 3

[0130] like Figure 3As shown, based on the above embodiments, this embodiment further provides a photovoltaic thermal system 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 reflector glass 2, a reflective coating 11, a supporting bottom layer 12, a back photovoltaic cell 3 and a second encapsulation layer 5 arranged in sequence from top to bottom.

[0131] The first transparent electrode 6 is usually 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 providing an electron channel to quickly transport the electrons generated by light excitation to the circuit. In addition, it can also reflect part of the light, increase the photocurrent density, and thus improve the conversion efficiency of the photovoltaic cell.

[0132] Since the first transparent electrode 6 has the function of providing an electron channel to quickly transport the electrons generated by light excitation to the circuit, in actual use, the first transparent electrode 6 and the electron transport layer 7 can be used either alone or in combination.

[0133] The light absorption layer 8 is the core part of the photovoltaic cell, which directly receives sunlight and generates electrical energy. Specifically, the light absorption layer 8 can absorb photon energy and excite electrons to transition from the valence band to the conduction band, forming a photocurrent. The choice of its material and thickness have an important influence on the conversion efficiency of the photovoltaic thermal system.

[0134] The present invention does not strictly limit the material of the light absorption layer 8. For example, perovskite-type organic metal halide semiconductors commonly used in semi-transparent perovskite solar cells, organic conjugated molecules commonly used in semi-transparent organic solar cells, and quantum dots commonly used in semi-transparent quantum dot solar cells can also be used. The selection of the material of the light absorption layer 8 enables the semi-transparent photovoltaic cell 1 to achieve a high photoelectric conversion efficiency while maintaining a certain light transmittance, thereby broadening the application field of photovoltaic technology.

[0135] The second transparent electrode 10 is similar to the first transparent electrode 6 and plays the role of providing a hole channel and collecting photocurrent. The second transparent electrode 10 ensures that the photogenerated holes can be smoothly transported to the circuit and form a closed loop with the external circuit to generate electrical energy.

[0136] Similarly, since the second transparent electrode 10 has the functions of providing a hole channel and collecting photocurrent, in actual use, the second transparent electrode 10 and the hole transport layer 9 can be used either alone or in combination.

[0137] The plane reflector glass 2 of the present invention includes float glass, ultra-white glass, low-iron glass, high-strength tempered glass, etc., and can be further preferably pyramid-shaped glass. The pyramid-shaped glass is used as the substrate of the translucent photovoltaic cell 1. The pyramid-shaped structure on its surface can not only improve the adhesion of the photovoltaic cell on the plane reflector glass 2, but also increase the absorption rate of visible light in the light absorption layer 8 of the perovskite solar cell, that is, reduce the transmittance of visible light in the photovoltaic cell, thereby improving the energy conversion efficiency of the photovoltaic cell.

[0138] The reflective coating 11 is arranged on the lower surface of the plane reflector glass 2 to further enhance the reflection effect of light. Through the reflective coating 11, more light can be reflected back to the light absorption layer 8, thereby improving the utilization rate of light and the conversion efficiency of the semi-transparent photovoltaic cell 1.

[0139] The supporting bottom layer 12 is a supporting structure of the semi-transparent photovoltaic cell 1 and is used to fix and support other layers, thereby ensuring the stability and reliability of the semi-transparent photovoltaic cell 1 during installation and use.

[0140] Each layer in the photovoltaic thermal system of this embodiment plays a different role in the photovoltaic thermal system, and together ensures the efficient, stable and reliable operation of the photovoltaic thermal system.

[0141] Example 4

[0142] like Figure 4-5 As shown, on the basis of the above embodiments, this embodiment further provides a photovoltaic thermal system that comprehensively utilizes solar energy, including a first encapsulation layer 4, a first anti-reflection 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 anti-reflection layer 14, a plane reflector glass 2, a reflective coating 11, a supporting bottom layer 12, a back photovoltaic cell 3 and a second encapsulation layer 5, which are arranged in sequence from top to bottom.

[0143] This embodiment adds a first anti-reflection layer 13 and a second anti-reflection 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 on the basis of Embodiment 3. Among them, the first anti-reflection layer 13 is arranged between the first encapsulation layer 4 and the first transparent electrode 6, which can effectively improve the transmittance of sunlight and reduce the reflection loss of light, thereby improving the light absorption efficiency. Specifically, the material of the first anti-reflection layer 13 includes any one or more of silicon dioxide, magnesium fluoride and calcium fluoride; the second anti-reflection layer 14 is arranged between the second transparent electrode 10 and the plane reflector glass 2, and is mainly used to enhance the transmittance of light.

[0144] In this embodiment, the second anti-reflection layer 14 can be a single-functional layer or a double-functional layer, wherein the material of the second anti-reflection layer 14 of the single-functional layer mainly includes any one or more of silicon dioxide and magnesium fluoride, and its thickness is 90-150 nm; and the second anti-reflection layer 14 of the double-functional layer mainly includes a high refractive index layer 15 and a low refractive index layer 16, wherein the material of the high refractive index layer 15 mainly includes any one or more of titanium dioxide and silicon nitride, and its thickness is 250-500 nm, and the material of the low refractive index layer 16 mainly includes any one or more of silicon dioxide and magnesium fluoride, and its thickness is 250-500 nm. One or more, with a thickness of 85-185nm, the double-functional layer second transmittance-enhancing layer 14 mainly utilizes the light interference effect between the layers to respectively enhance the light transmission or reflection of specific bands, so as to accurately control the transmission of light in the ultraviolet, visible and infrared bands. Therefore, the setting of the double-functional layer second transmittance-enhancing layer 14 can not only enhance the transmittance of infrared light, but also enhance the reflectivity 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 plane reflector glass 2, so that the infrared light is reflected as much as possible.

[0145] In this embodiment, the first interface modification layer 17 is arranged between the first transparent electrode 6 and the electron transport layer 7, and is 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 arranged between the electron transport layer 7 and the light absorption layer 8, and is mainly used to optimize electron transport, reduce interface defects and charge recombination, thereby improving energy conversion efficiency; the third interface modification layer 19 is arranged between the light absorption layer 8 and the hole transport layer 9, and is mainly used to improve interface charge transport, reduce charge load, and improve energy conversion efficiency; the fourth interface modification layer 20 is arranged between the hole transport layer 9 and the second transparent electrode 10, and is mainly used to optimize interface contact, reduce charge load loss, improve hole extraction efficiency and protect the underlying material.

[0146] Example 5

[0147] This embodiment provides a method for preparing the photovoltaic thermal system, comprising the following steps:

[0148] S1, select float glass, ultra-clear glass, low-iron glass or high-strength tempered glass as the plane reflector glass 2;

[0149] The plane reflector glass 2 may further be a pyramid glass. Specifically, a physical or chemical method may be used to prepare a pyramid structure on a glass plate. For example, a laser beam may be used to etch the surface of a substrate to form a pyramid micro-nano structure. The parameters of the laser etching (such as power, scanning speed, etching depth, etc.) may be adjusted according to the specific requirements of the pyramid structure.

[0150] In addition to laser etching, pyramidal structures can also be prepared by methods such as melt recrystallization, nanoimprinting technology, chemical etching (such as hydrofluoric acid, silicate solution), mechanical grinding, and plasma treatment.

[0151] 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, nanostructured film, etc. are uniformly deposited on the lower surface of the plane reflector glass 2 by magnetron sputtering or evaporation vacuum coating technology, and the thickness is preferably 50-300 nm;

[0152] S3, preparation of the bearing bottom layer 12: depositing a polymer substrate or reinforcing glass fiber 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 reflector glass 2, and the thickness thereof is preferably 500 μm-2 mm;

[0153] S4, preparation of the second anti-reflection layer 14: depositing a high refractive index material and a low refractive index material in sequence on the upper surface of the plane reflector glass 2;

[0154] Among them, for the second anti-reflection layer 14 of the single functional layer, silicon dioxide, magnesium fluoride, etc. are prepared on the upper surface of the plane reflector glass 2 by thermal evaporation, vacuum sputtering, chemical vapor deposition, etc., and the thickness thereof is 90-150nm to enhance the transmittance of light;

[0155] For the second anti-reflection layer 14 of the double-functional layer, titanium dioxide or silicon nitride is first deposited on the upper surface of the plane reflector glass 2 by thermal evaporation, electron beam evaporation, vacuum sputtering, etc. to form a high refractive index layer 15 with a thickness of 250nm-500nm, and then silicon dioxide or magnesium fluoride is deposited to form a low refractive index layer 16 with a thickness of 85nm-185nm. The second anti-reflection layer 14 of the double-functional layer can not only enhance the transmittance of infrared light, but also enhance the reflectance of ultraviolet light and visible light.

[0156] S5, preparation of the second transparent electrode 10: sputtering an indium tin oxide, fluorine-doped tin oxide or zinc oxide thin film on the surface of the second anti-reflection layer 14 by a magnetron sputtering method, and then annealing at a temperature of 200° C. to 300° C. for 30 to 60 minutes to form a second transparent electrode 10 with a thickness of 80 to 150 nm;

[0157] S6, preparation of the fourth interface modification layer 20: preparing the fourth interface modification layer 20 on the second transparent electrode 10 by spin coating, slit coating or vacuum thermal evaporation, wherein 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 the thickness thereof is 2-10 nm;

[0158] S7, preparation of hole transport layer 9: coating a hole transport layer solution on the fourth interface modification layer 20 by spin coating, slit coating or vacuum thermal evaporation to form a hole transport layer 9, wherein the hole transport layer solution comprises any one or more of nickel oxide, molybdenum oxide, porphyrin self-assembled monolayer, PTAA, two-dimensional graphene and graphene oxide, and the thickness thereof is 20-100 nm;

[0159] S8, preparation of the third interface modification layer 19: preparing the third interface modification layer 19 on the hole transport layer 9 by spin coating, slit coating or vacuum thermal evaporation, wherein 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 the thickness thereof is 2nm-8nm;

[0160] S9, preparation of light absorption layer 8: preparing light absorption layer 8 on hole transport layer 9 by slit coating method, solution method or evaporation method, wherein the light absorption layer 8 material has a band gap of 1.70 eV-2.30 eV, mainly absorbs ultraviolet light and visible light, and has a thickness of 300 nm-700 nm;

[0161] S10, preparation of the second interface modification layer 18: preparing the second interface modification layer 18 on the light absorption layer 8 by spin coating, slit coating or vacuum thermal evaporation, wherein 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-buthoxylate, and the thickness thereof is 20nm-50nm;

[0162] S11, preparation of electron transport layer 7: preparing electron transport layer 7 on the second interface modification layer 18 by slit coating method or thermal evaporation method, wherein the material of electron transport layer 7 includes any one or more of fullerene and its derivatives, zinc oxide and zirconium dioxide, and the thickness thereof is 30-100 nm;

[0163] S12, preparation of the first interface modification layer 17: preparing the first interface modification layer 17 on the electron transport layer 7 by spin coating, slit coating or vacuum thermal evaporation, wherein 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 the thickness thereof is 5 nm-10 nm;

[0164] S13, preparation of the first transparent electrode 6: a multilayer transparent electrode (Au / Ag / MoO x ), wherein the material of the first transparent electrode 6 includes any one or more of indium tin oxide, fluorine-doped zinc oxide and tin oxide, and the thickness thereof is 50nm-300nm;

[0165] S14, preparation of the first anti-reflection layer 13: depositing or coating silicon dioxide, magnesium fluoride or calcium fluoride on the first transparent electrode 6 by chemical vapor deposition, physical vapor deposition or slit coating to prepare the first anti-reflection layer 13, wherein the thickness of the first anti-reflection layer 13 is 3nm-10nm;

[0166] S15, preparation of the first encapsulation layer 4: using spin coating, blow molding, coating to prepare encapsulation materials such as polyimide, polyethylene and fluoropolymer on the semi-transparent photovoltaic cell 1, the thickness of which is 1-10 μm, mainly plays a protective and sealing role, used to prevent the intrusion of moisture and oxygen, and extend the service life of the photovoltaic thermal system;

[0167] S16, pasting the prepared perovskite solar cell, silicon solar cell or copper indium gallium selenide photovoltaic cell to the back side of the supporting bottom layer 12 with glue, and ensuring the reliability, long-term stability and compatibility between materials of pasting;

[0168] The following methods can be used:

[0169] Step 1 Preparation

[0170] (1) Clean the reflector surface

[0171] Use isopropyl alcohol (IPA) or deionized water to clean the lower surface of the carrier substrate 12 to ensure that it is free of dust and oil;

[0172] Wipe dry with a lint-free cloth or dry in a clean environment.

[0173] (2) Check the back of the battery

[0174] Make sure the lower surface of the carrier substrate 12 is flat and free of contaminants.

[0175] Confirm the bonding area and layout according to the battery size.

[0176] Step 2 Glue selection

[0177] Choose glue with high transparency, low shrinkage, weather resistance and good bonding strength. Such as the following glue types:

[0178] 1. Epoxy resin glue

[0179] Advantages: high bonding strength, good weather resistance, suitable for environments exposed to sunlight and high temperature for a long time.

[0180] 2. UV curing adhesive

[0181] Advantages: Fast curing, suitable for transparent materials, suitable for indoor or UV light accessible areas.

[0182] 3. Silicone glue

[0183] Advantages: high temperature resistance, UV resistance, good elasticity, suitable for environments with thermal expansion and contraction.

[0184] Step 3: Bonding

[0185] (1) Apply glue

[0186] Apply glue evenly on the lower surface of the carrier bottom layer 12. The thickness is recommended to be 0.1-0.3mm to ensure that bubbles are removed after bonding and the battery performance is not affected. Pay attention to the application range of glue and do not cover the battery electrode area.

[0187] (2) Bonding the back photovoltaic cell 3

[0188] Align the back photovoltaic cell 3 with the supporting bottom layer 12, gently fit them together, and use appropriate pressure to squeeze out excess glue and bubbles. Use a clamp or a special fixing frame to ensure that the cell does not slide during the bonding process.

[0189] (3) Curing glue

[0190] Epoxy resin glue: Curing at room temperature or heating to 40-60℃. The curing time is adjusted according to the product instructions, generally 12-24h.

[0191] UV curing adhesive: Cured under UV light source, the irradiation intensity is 200-500mW / cm 2 The curing time is generally 5-10 minutes.

[0192] Silicone adhesive: naturally cures at room temperature, the curing time is 24-48h.

[0193] S17 , preparation of the second encapsulation layer 5 : prepare the second encapsulation layer 5 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 .

[0194] Example 5

[0195] like Figure 6-8 As shown, the most preferred photovoltaic thermal system of the present invention is applied to tower-type thermal power stations and plate-type thermal power stations.

[0196] In tower-type solar thermal power stations and plate-type solar thermal power stations, the semi-transparent photovoltaic cell 1 is mainly used to absorb visible light and ultraviolet light in direct sunlight, and the plane reflector glass 2 is used to reflect the remaining visible light, ultraviolet light and all infrared light of the direct light passing through the semi-transparent photovoltaic cell 1, wherein the reflected ultraviolet light and visible light can be reabsorbed by the semi-transparent photovoltaic cell 1 for photoelectric conversion, and the infrared light is accurately reflected to the solar thermal collector for photothermal conversion. The back photovoltaic cell 3 on the back of the plane reflector glass 2 is used to collect unused direct light, sunlight reflected from the ground, and other ambient light. In addition, the solar tracking system in the solar thermal power station will also adjust the rotation angle so that the sunlight is incident on the photovoltaic thermal system at the optimal angle.

[0197] Studies have shown that applying the photovoltaic thermal system of the present invention to tower-type solar thermal power stations and plate-type solar thermal power stations can reduce the overall system's electricity cost by about 10%-25%. In addition, the design of the photovoltaic thermal system of the present invention also improves the energy output density per unit area, and the energy utilization rate can be increased to about 400W-600W per square meter, which is suitable for large-scale application. Moreover, the solar thermal system is more effective in areas with high radiation intensity (such as direct sunlight exceeding 2000W / m 2 The use of the system in the region can further improve the photothermal conversion efficiency and reduce operating costs.

[0198] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic thermal system for comprehensive utilization of solar energy, characterized in that: It comprises a semi-transparent photovoltaic cell (1), a plane reflector glass (2) and a back photovoltaic cell (3) which are arranged in sequence from top to bottom.

2. The photovoltaic thermal system according to claim 1, characterized in that: The surface of the back photovoltaic cell (3) is coated with a light capture layer, and the material of the light capture layer includes any one of a conjugated polymer, fullerene and its derivatives, zinc oxide and titanium dioxide.

3. The photovoltaic thermal system 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; The nano light trap structure includes any one or more of a nano column array, a nano cone structure and a nano hole array; The material of the metamaterial coating includes any one of metal nanoparticles and titanium dioxide-doped metal nanoparticles.

4. The photovoltaic thermal system according to claim 1, characterized in that: A nano-metal grid transparent electrode is arranged on the glass substrate of the back photovoltaic cell (3).

5. The photovoltaic thermal system according to claim 1, characterized in that: The semi-transparent photovoltaic cell (1) comprises any one of a semi-transparent perovskite solar cell, a semi-transparent organic solar cell and a semi-transparent quantum dot solar cell; The back photovoltaic cell (3) comprises any one of a silicon solar cell, a perovskite solar cell, a cadmium telluride solar cell, a gallium arsenide solar cell, an organic solar cell, a quantum dot solar cell and a copper indium gallium selenide solar cell.

6. The photovoltaic thermal system according to claim 1, characterized in that: The invention comprises a first encapsulation layer (4), a semi-transparent photovoltaic cell (1), a plane reflector glass (2), a back photovoltaic cell (3) and a second encapsulation layer (5) which are arranged in sequence from top to bottom.

7. The photovoltaic thermal system according to claim 1, characterized in that: The invention comprises, arranged in order 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 reflector glass (2), a reflective coating (11), a supporting bottom layer (12), a back photovoltaic cell (3) and a second encapsulation layer (5).

8. The photovoltaic thermal system according to claim 7, 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 anti-reflection layer (13) is provided between the first encapsulation layer (4) and the first transparent electrode (6). A second anti-reflection layer (14) is provided between the second transparent electrode (10) and the plane reflector glass (2).

9. The method for preparing a photovoltaic thermal system according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Selecting float glass, ultra-clear glass, low-iron glass or high-strength tempered glass as the plane reflector glass (2); S2, uniformly depositing a high reflectivity material on the lower surface of the plane reflector glass (2); S3, depositing a polymer substrate or reinforcing glass fiber on the surface of the reflective coating (11); S4, depositing a high refractive index material and a low refractive index material in sequence on the upper surface of the plane reflector glass (2) to prepare a second anti-reflection layer (14); S5, sputtering an indium tin oxide, fluorine-doped tin oxide or zinc oxide thin film on the surface of the second anti-reflection layer (14) by a magnetron sputtering method to prepare a second transparent electrode (10); S6, preparing a fourth interface modification layer (20) on the second transparent electrode (10); S7, coating a hole transport layer solution on the fourth interface modification layer (20) to form a hole transport layer (9); S8, preparing a third interface modification layer (19) on the hole transport layer (9); S9, preparing a light absorbing layer (8) on the third interface modification layer (19); S10, preparing a second interface modification layer (18) on the light absorbing layer (8); S11, preparing an electron transport layer (7) on the second interface modification layer (18); S12, preparing a first interface modification layer (17) on the electron transport layer (7); S13, preparing one or more transparent electrodes on the first interface modification layer (17); S14, depositing or coating silicon dioxide, magnesium fluoride or calcium fluoride on the first transparent electrode (6) to prepare a first anti-reflection layer (13); S15, preparing a first encapsulation layer (4) on the first anti-reflection layer (13); S16, installing a back photovoltaic cell (3) on a side of the supporting bottom layer (12) away from the reflective coating (11); S17, preparing a second encapsulation layer (5) on the side of the back photovoltaic cell (3) away from the supporting bottom layer (12).

10. Application of the photovoltaic thermal system according to any one of claims 1 to 8 in a tower-type thermal power station or a plate-type thermal power station.

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