Photovoltaic modules with dual passive auxiliary cooling and surface hydrophobic function

Abstract

This invention discloses a photovoltaic module with dual passive assisted cooling and surface hydrophobicity, comprising: a photovoltaic module body; a light-transmitting radiative cooling layer disposed on the light-facing surface of the photovoltaic module body; the surface of the light-transmitting radiative cooling layer opposite to the photovoltaic module body having a microstructure; and a hygroscopic hydrogel disposed on the back surface of the photovoltaic module body. The photovoltaic module provided by this invention achieves a certain degree of cooling effect through the light-transmitting radiative cooling layer on its surface, while utilizing the hydrophobicity of the microstructure on the surface of the radiative cooling layer to provide good self-cleaning effect against dust and other dirt; furthermore, the hygroscopic hydrogel disposed on the back of the photovoltaic module achieves a good cooling effect through daytime moisture evaporation cooling.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity. Background Technology

[0002] Currently, there are two main methods for cooling photovoltaic cells: air cooling and water cooling. Although air cooling is simple in structure and the most economical, its cooling effect is not ideal, and the heat released into the surrounding air, if not dissipated in time, will cause the ambient temperature to rise, further affecting the cooling effect. Water cooling, on the other hand, has a relatively better cooling effect and can also recycle hot water. However, water cooling structure is more complex and has higher cooling costs and consumes a large amount of water, making it unsuitable for large-scale photovoltaic cooling.

[0003] Passive radiation cooling, a technology that cools itself by emitting thermal radiation into the extremely low-temperature environment of outer space (approximately 3K), has received widespread attention in recent years. Passive radiation cooling requires no energy consumption; the heat from an object is emitted into outer space through the Earth's atmosphere in the form of infrared thermal radiation within the atmospheric window band (8-13μm), thus achieving self-cooling. Research has shown that by reasonably modifying the spectral characteristics of the object's surface, a cooling effect below ambient temperature can be achieved even under direct sunlight during the day. Therefore, applying this technology to the cooling of photovoltaic modules may be of great significance. For example, patent publication number CN110660875A, "A Method for Cooling Photovoltaic Modules Using Transparent Mid-Infrared Radiation Cellulose Thin Film," utilizes this technology to cool photovoltaic modules. However, the method mentioned in this patent involves embedding a mid-infrared radiative cellulose film with radiative cooling effect between the glass and the photovoltaic cell. This causes the infrared spectral radiation emitted by the cellulose film to be affected by the spectral selective absorption of the glass, thus affecting the cooling effect of the photovoltaic module. In addition, the glass surface does not have a hydrophobic self-cleaning function, and dust accumulation over a long period of time is difficult to remove simply by rainwater, further affecting the radiative cooling effect. Although the patent CN202111383955.6, "Composite Coating Material with Hydrophobic Radiative Cooling and its Preparation Method," proposes a method for preparing a hydrophobic radiative cooling film, the transmittance of the film prepared by this method in the visible light band is not ideal. If applied to the surface of a photovoltaic module, it will affect the absorption of visible light by the photovoltaic module, thereby leading to a decrease in photoelectric conversion efficiency.

[0004] Therefore, the existing technology still needs further improvement and enhancement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function. This photovoltaic module has a good cooling effect and a good self-cleaning effect on dust and other dirt.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A photovoltaic module with dual passive assisted cooling and surface hydrophobicity functions, comprising:

[0008] Photovoltaic module body;

[0009] A light-transmitting radiation-cooling layer is disposed on the light-facing surface of the photovoltaic module body; the surface of the light-transmitting radiation-cooling layer opposite to the photovoltaic module body has a microstructure.

[0010] A moisture-absorbing hydrogel is disposed on the back surface of the photovoltaic module body.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0012] As a preferred technical solution, the photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity features a light-transmitting radiative cooling layer that exhibits strong infrared thermal radiation capability in the 8-13μm spectral band. 。

[0013] As a preferred technical solution, the photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function, wherein the light-transmitting radiative cooling layer comprises a polydimethylsiloxane film.

[0014] As a preferred technical solution, the photovoltaic module with dual passive assisted cooling and surface hydrophobic functions, wherein the method for preparing the polydimethylsiloxane thin film includes:

[0015] Provide molds with microstructures on their surfaces;

[0016] Provides a mixture containing polydimethylsiloxane and a curing agent;

[0017] The mixture is coated onto the surface of the mold, and after drying and demolding, the polydimethylsiloxane film is obtained.

[0018] As a preferred technical solution, the photovoltaic module with dual passive assisted cooling and surface hydrophobic functions, wherein the preparation method further includes:

[0019] The polydimethylsiloxane film is subjected to plasma treatment, and the microstructure on the surface of the plasma-treated polydimethylsiloxane film is fluorinated with a fluorinating agent to obtain a hydrophobic polydimethylsiloxane film. Plasma treatment achieves cleaning, and the microstructure's surface activity is enhanced after plasma treatment, facilitating its interaction with the fluorinating agent. Furthermore, the fluorination treatment strengthens the hydrophobic function of the microstructure.

[0020] As a preferred technical solution, in the photovoltaic module with dual passive assisted cooling and surface hydrophobicity, the thickness of the light-transmitting radiative cooling layer is 100-300 μm.

[0021] As a preferred technical solution, the photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity functions, wherein the process of fluorinating the microstructure of the plasma-treated polydimethylsiloxane film with a fluorinating agent to obtain a hydrophobic polydimethylsiloxane film specifically includes:

[0022] 1H,1H,2H,2H-perfluorodecyltrichlorosilane was mixed with n-hexane to obtain a fluorinating agent;

[0023] The fluorinating agent is sprayed onto the microstructure on the surface of the plasma-treated polydimethylsiloxane film until the polydimethylsiloxane film swells.

[0024] The polydimethylsiloxane film that has swollen is placed in a sealed container, and after a period of time it is taken out and left to stand to obtain a hydrophobic polydimethylsiloxane film.

[0025] As a preferred technical solution, in the photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function, the volume ratio of n-hexane to 1H,1H,2H,2H-perfluorodecyltrichlorosilane is 2000-3000:1.

[0026] As a preferred technical solution, the photovoltaic module with dual passive assisted cooling and surface hydrophobic functions, wherein the method for preparing the hygroscopic hydrogel includes:

[0027] Acrylamide, calcium chloride powder, initiator and crosslinking agent are dispersed in water to obtain a precursor solution;

[0028] Porous silicon carbide was added to the precursor solution, ultrasonically treated, and tetramethylethylenediamine was added to the precursor solution. After curing, the hygroscopic hydrogel was obtained.

[0029] As a preferred technical solution, the photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function is wherein the mass ratio of acrylamide, calcium chloride powder and water is 1:1-3:4-8.

[0030] Beneficial effects: Compared with the prior art, the photovoltaic module provided by the present invention achieves a certain degree of cooling effect through the light-transmitting radiation cooling layer on the surface. At the same time, the hydrophobicity of the microstructure on the surface of the radiation cooling layer provides a good self-cleaning effect for dust and other dirt. In addition, the moisture-absorbing hydrogel set on the back of the photovoltaic module can achieve a good cooling effect for the photovoltaic module by evaporating moisture during the day. Attached Figure Description

[0031] Figure 1 A schematic diagram of a photovoltaic module structure with dual passive auxiliary cooling and surface hydrophobicity provided by the present invention;

[0032] Figure 2 This is a magnified view of the microstructure of a hydrophobic polydimethylsiloxane film.

[0033] Figure 3 This is a schematic diagram of the internal structure of the moisture-absorbing hydrogel block. Detailed Implementation

[0034] This invention provides a photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0037] like Figure 1 As shown, Figure 1This is a schematic diagram of a photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity. The photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity includes: a regular photovoltaic module 20, a light-transmitting radiative cooling layer 10 pasted on the upper surface of the regular photovoltaic module 20, a moisture-absorbing hydrogel 30 closely attached to the back of the regular photovoltaic module 20, a frame 40 for fixing the regular photovoltaic module 20 and the moisture-absorbing hydrogel 30, and a bottom stainless steel support mesh 50.

[0038] In this embodiment, a certain degree of cooling effect is achieved through a light-transmitting radiative cooling layer on the surface. Simultaneously, the hydrophobicity of the microstructure on the surface of this radiative cooling layer provides a good self-cleaning effect against dust and other contaminants. Furthermore, the moisture-absorbing hydrogel disposed on the back of the photovoltaic module achieves a good cooling effect through daytime moisture evaporation. The specific shape of the microstructure can be set as needed.

[0039] In this embodiment, the term "ordinary photovoltaic module 20" refers to the same thing as the photovoltaic module body. "Ordinary photovoltaic module" is a photovoltaic module in the general sense. The technical solution provided by this invention addresses improvements to it by setting a radiative cooling layer on the light-facing side and a moisture-absorbing hydrogel on the backside, without involving any changes to the internal structure of the photovoltaic module. The specific structure of the photovoltaic module is not described in detail here. The specific structure and dimensions of the frame 40 and the stainless steel support mesh 50 can be set according to the shape of the photovoltaic module body, as long as it meets its functional requirements; the specific structure is not limited here.

[0040] In this embodiment, the translucent radiative cooling layer 10 refers to a film layer capable of cooling an object by emitting thermal radiation into outer space. That is, a film layer with passive radiative cooling function. This film layer requires no energy consumption; the object's heat is emitted into outer space through the Earth's atmosphere in the form of infrared thermal radiation in the atmospheric window band (8-13μm), thereby achieving its own cooling effect. Simultaneously, because it is translucent, it does not affect the normal operation of the photovoltaic module.

[0041] In this embodiment, the light-transmitting radiation cooling layer 10 can be a polydimethylsiloxane (PDMS) layer, and the thickness of the PDMS thin film layer can be 300 μm.

[0042] As an example, this PDMS thin film layer can be prepared using the following method:

[0043] 1) Pour the polydimethylsiloxane (PDMS) main agent and curing agent into the reagent bottle at a mass ratio of 10:1, and stir magnetically for 1 hour at room temperature. Then, perform repeated vacuuming treatment until all air bubbles in the liquid are removed.

[0044] 2) Select sandpaper with a grit of 2500 (for molds with microstructures on the surface), and ultrasonically clean it for 1 minute each with anhydrous ethanol and deionized water. Then dry it at 60°C for 30 minutes. After drying, flatten the back of the sandpaper and stick it to the flat glass.

[0045] 3) Place the flat glass with 2500 grit sandpaper attached in 2) on the surface of the casting machine, and set the scraper height to 500μm and the speed to 3mm / s. Then, pour the PDMS reagent with air bubbles removed in 1) evenly onto the sandpaper surface, start the machine, and the scraper moves at a set height and speed above the sandpaper to form a PDMS wet film of uniform thickness on the sandpaper surface.

[0046] 4) The PDMS wet film prepared in 3) along with the substrate flat glass was transferred to a sealed box and preheated at 40°C for 30 minutes. Then, the temperature was increased to 60°C to dry and cure for 3 hours. After drying, the PDMS film was separated from the sandpaper to obtain a PDMS film with one smooth side and a surface microstructure on the other side. The magnified image of its microstructure is shown below. Figure 2 As shown, PDMS membrane 12 and microstructure 11.

[0047] 5) Mix n-hexane and 1H,1H,2H,2H-perfluorodecyltrichlorosilane at a volume ratio of 2000:1 and stir until homogeneous, then load the mixture into a sprayer;

[0048] 6) Place the PDMS film with surface microstructure prepared in 4) into a plasma cleaner and plasma treat the side with microstructure for 5 minutes. Then remove it and uniformly spray the diluted fluorinating agent from 5) onto the PDMS surface with microstructure until the PDMS film swells. Then place it in a sealed box and seal it for 1 hour. After the fluorinating agent solvent on the PDMS film has completely evaporated, the hydrophobic PDMS film can be obtained.

[0049] In this embodiment, the moisture-absorbing hydrogel 30, which is closely attached to the back of the ordinary photovoltaic module 20, has the following internal structure: Figure 3 As shown, it consists of a moisture-absorbing hydrogel 31 and an internal porous silicon carbide block 32, wherein the moisture-absorbing hydrogel 31 encapsulates and fills the internal porous structure of the porous silicon carbide block 32. It should be noted that the shape of the moisture-absorbing hydrogel 30 can be block-shaped, sheet-shaped, or other shapes. The specific shape and size can be optimized according to the size of the photovoltaic module and its heat dissipation capacity.

[0050] The following is an example of the preparation process for a block-shaped hygroscopic hydrogel block:

[0051] 1) Place the porous silicon carbide block in a box, add a certain amount of deionized water, and clean it with ultrasound for 5 minutes. Then, take it out and put it in a forced-air drying oven to dry at 60°C for 3 hours for later use.

[0052] 2) Place acrylamide, calcium chloride powder and deionized water into a mold box in a mass ratio of 1:2:5, stir well, sonicate for 1 minute, then purge with nitrogen for 10 minutes, and cover for later use.

[0053] 3) Dissolve a small amount of potassium persulfate initiator and N,N′-methylenebisacrylamide crosslinking agent in deionized water, add them to the solution prepared in step 2), and sonicate for 1 minute; then put the porous silicon carbide block dried in step 1) into the solution, sonicate for another minute, and then uniformly drop a small amount of tetramethylethylenediamine into the solution. After standing for 5 hours, the hygroscopic hydrogel block can be obtained.

[0054] In this embodiment, the hygroscopic hydrogel block can absorb the heat generated by the photovoltaic module during the day and carry away the heat through its own moisture evaporation, thereby better cooling the photovoltaic module. Simultaneously, at night when the temperature drops, it can spontaneously absorb water vapor from the surrounding air to replenish the moisture lost through daytime evaporation. Furthermore, at night, the radiative cooling effect of the hydrophobic PDMS film on the photovoltaic module surface can lower the temperature of the hygroscopic hydrogel block, facilitating its nighttime water vapor absorption.

[0055] In this embodiment, the photovoltaic module has dual passive auxiliary cooling and surface self-cleaning functions through the synergistic effect of the hydrophobic PDMS film and the moisture-absorbing hydrogel block.

[0056] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity functions, characterized in that, include: Photovoltaic module body; A light-transmitting radiation-cooling layer is disposed on the light-facing surface of the photovoltaic module body; The surface of the radiation cooling layer away from the photovoltaic module body has a microstructure; A moisture-absorbing hydrogel is disposed on the back surface of the photovoltaic module body; The light-transmitting radiation cooling layer includes a polydimethylsiloxane film; The thickness of the light-transmitting radiation cooling layer is 100-300 μm; The method for preparing the hygroscopic hydrogel includes: Acrylamide, calcium chloride powder, initiator and crosslinking agent are dispersed in water to obtain a precursor solution; Porous silicon carbide was added to the precursor solution, ultrasonically treated, and tetramethylethylenediamine was added to the precursor solution. After curing, the hygroscopic hydrogel was obtained. The mass ratio of acrylamide, calcium chloride powder and water is 1:1-3:4-8; The polydimethylsiloxane film is subjected to plasma treatment, and the microstructure on the surface of the plasma-treated polydimethylsiloxane film is fluorinated with a fluorinating agent to obtain a hydrophobic polydimethylsiloxane film.

2. The photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function according to claim 1, characterized in that, The transparent radiation cooling layer has infrared thermal radiation capability in the 8-13μm spectral band.

3. The photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function according to claim 1, characterized in that, The method for preparing the polydimethylsiloxane film includes: Provide molds with microstructures on their surfaces; Provides a mixture containing polydimethylsiloxane and a curing agent; The mixture is coated onto the surface of the mold, and after drying and demolding, the polydimethylsiloxane film is obtained.

4. The photovoltaic module with dual passive auxiliary cooling and surface hydrophobicity functions according to claim 3, characterized in that, The process of fluorinating the microstructure on the surface of the plasma-treated polydimethylsiloxane film with a fluorinating agent to obtain a hydrophobic polydimethylsiloxane film specifically includes: 1H,1H,2H,2H-perfluorodecyltrichlorosilane was mixed with n-hexane to obtain a fluorinating agent; The fluorinating agent is uniformly sprayed onto the microstructure on the surface of the plasma-treated polydimethylsiloxane film until the polydimethylsiloxane film swells. The polydimethylsiloxane film that has swollen is placed in a sealed container, and after a period of time it is taken out and left to stand to obtain a hydrophobic polydimethylsiloxane film.

5. The photovoltaic module with dual passive auxiliary cooling and surface hydrophobic function according to claim 4, characterized in that, The volume ratio of n-hexane to 1H,1H,2H,2H-perfluorodecyltrichlorosilane is 2000-3000:1.

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