Preparation method of photovoltaic module and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic modules, and discloses a preparation method of a photovoltaic module and the photovoltaic module, and the preparation method of the photovoltaic module comprises the steps: providing an initial photovoltaic module which comprises a solar cell and an upper cover plate located on the solar cell; coating a self-cleaning coating material on the surface of one side, far away from the solar cell, of the upper cover plate; and based on an infrared illumination mode, carrying out curing treatment on the self-cleaning coating material to form a self-cleaning coating so as to obtain the photovoltaic module. The self-cleaning coating is formed on the surface of the photovoltaic module in an infrared illumination mode, it can be ensured that hydrophobic particles (such as titanium dioxide or zinc oxide) in a self-cleaning coating material are evenly dispersed, the light transmittance is improved, infrared energy can be concentrated on the surface of the self-cleaning coating, and a compact hydrophobic layer (the contact angle is larger than 150 degrees) is formed.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic modules, and in particular to a method for preparing a photovoltaic module and a photovoltaic module. Background Art

[0002] Solar photovoltaic (PV) panels convert sunlight into electricity through the photovoltaic effect. When sunlight strikes the surface of a panel, a photocurrent is generated. However, PV panels exposed outdoors inevitably accumulate dust, which reflects, absorbs, and scatters solar radiation, reducing power generation.

[0003] Currently, a titanium dioxide (TiO2) film (i.e., a self-cleaning coating) is applied to the surface of photovoltaic modules. This coating's hydrophobicity allows rainwater (or snow) to self-clean dust from the module's surface. However, when using traditional thermal curing methods (such as ovens) to form the self-cleaning coating, the high temperatures can limit the coating's hydrophobicity and light transmittance, impacting the module's power generation efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a method for preparing a photovoltaic module and a photovoltaic module to improve the problem that the hydrophobicity and light transmittance of the self-cleaning coating are limited due to high temperature, which affects the power generation efficiency of the photovoltaic module.

[0005] In a first aspect, the present invention provides a method for preparing a photovoltaic module, the method comprising: providing an initial photovoltaic module, wherein the initial photovoltaic module comprises solar cells and an upper cover plate located on the solar cells; coating a self-cleaning coating material on a surface of the upper cover plate away from the solar cells; and curing the self-cleaning coating material based on infrared light to form a self-cleaning coating to obtain a photovoltaic module.

[0006] In this embodiment, the self-cleaning coating material is cured using infrared light to form a self-cleaning coating, resulting in a super-hydrophobic surface. When rain falls on the photovoltaic modules, it gathers into water droplets. Since the photovoltaic modules are installed at an angle, the water droplets immediately flow away, simultaneously washing away any dust on the surface of the photovoltaic modules. This enhances the self-cleaning ability, prevents dust from affecting the power generation efficiency of the photovoltaic modules, and reduces maintenance costs. Furthermore, the self-cleaning coating has high light transmittance (greater than 90%) and UV resistance, further maintaining the high power generation efficiency of the photovoltaic modules.

[0007] In an optional embodiment, the process parameters of the infrared light irradiation method include temperature, time and wavelength. The temperature ranges from 20°C to 40°C, the time ranges from 5min to 10min, and the wavelength ranges from 16.7μm to 25μm.

[0008] In this embodiment, the temperature of the infrared light is limited to 20° C. to 40° C., the time is limited to 5 min to 10 min, and the wavelength is limited to 16.7 μm to 25 μm, so as to optimize the hydrophobicity and light transmittance of the self-cleaning coating.

[0009] In an optional embodiment, coating the self-cleaning coating material on the surface of the upper cover away from the solar cell includes: coating the self-cleaning coating material on the surface of the upper cover away from the solar cell by a spraying robot.

[0010] In an optional embodiment, before coating the self-cleaning coating material on the surface of the upper cover away from the solar cell by the spraying robot, the method further includes: determining the moving speed of the spraying robot based on the thickness of the self-cleaning coating to be formed.

[0011] In an optional embodiment, determining the movement speed of the spraying robot based on the thickness of the self-cleaning coating to be formed includes: determining the movement speed of the spraying robot based on the thickness of the self-cleaning coating to be formed by the following formula:

[0012]

[0013] Wherein, d represents the thickness of the self-cleaning coating to be formed, k represents the transfer efficiency of the self-cleaning coating material, Q represents the flow rate of the spray gun, v represents the moving speed of the spray robot, and w represents the spraying width.

[0014] In this embodiment, the moving speed of the spraying robot is determined by a formula, so that the thickness of the self-cleaning coating can be more accurately controlled to the target thickness, avoiding secondary processing.

[0015] In an optional embodiment, the thickness of the self-cleaning coating ranges from 200 nm to 1 μm, and the moving speed of the spraying robot ranges from 15 cm / s to 25 cm / s.

[0016] In this embodiment, the thickness of the self-cleaning coating is limited to between 200 nm and 1 μm, which can well balance superhydrophobicity (such as a contact angle greater than 160°) and light transmittance.

[0017] In an optional embodiment, the self-cleaning coating material includes nano-sized zinc oxide and / or nano-sized titanium dioxide.

[0018] In an optional embodiment, the self-cleaning coating material includes polydimethylsiloxane, hydrophobic nano zinc oxide, octyltriethoxysilane, methyltriethoxysilane and n-hexane solvent, wherein the mass percentage content of polydimethylsiloxane is 8% to 12%, the mass percentage content of hydrophobic nano zinc oxide is 1% to 3%, the mass percentage content of octyltriethoxysilane is 0.5% to 2%, the mass percentage content of methyltriethoxysilane is 2% to 3%, and the rest is n-hexane solvent.

[0019] In a second aspect, the present invention provides a photovoltaic module, which is prepared by the method for preparing a photovoltaic module according to the first aspect or any corresponding embodiment thereof.

[0020] In an optional embodiment, the self-cleaning coating includes a plurality of sub-coatings stacked from bottom to top, wherein the sub-coating includes a bonding layer and a hydrophobic layer located on one side surface of the bonding layer, and the bottommost bonding layer among the plurality of sub-coatings is arranged on the upper cover plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in related technologies, the following briefly introduces the drawings required for use in the specific embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 is a schematic flow chart of a method for preparing a photovoltaic module according to an embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of an initial photovoltaic assembly according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic structural diagram of a self-cleaning coating provided on an initial photovoltaic module according to an embodiment of the present invention;

[0025] Figure 4 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present invention;

[0026] Figure 5 is a schematic structural diagram of another photovoltaic assembly according to an embodiment of the present invention;

[0027] Figure 6 is a schematic flow chart of another method for preparing a photovoltaic module according to an embodiment of the present invention;

[0028] Figure 7 is a schematic diagram of a spray-applied self-cleaning coating material according to an embodiment of the present invention;

[0029] Figure 8 is a schematic structural diagram of another initial photovoltaic module provided with a self-cleaning coating according to an embodiment of the present invention;

[0030] Figure 9 3 is a schematic structural diagram of another photovoltaic assembly according to an embodiment of the present invention.

[0031] Figure numerals: 210, backboard; 220, first ethylene-vinyl acetate copolymer layer; 230, solar cell; 240, second EVA layer; 250, upper cover; 260, self-cleaning coating; 261, sub-coating; 2611, bonding layer; 2612, hydrophobic layer; 270, frame; 280, junction box; 700, spraying robot. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. According to the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the present invention.

[0033] Solar photovoltaic power generation technology has become a key path to energy conservation and emission reduction, playing an increasingly prominent role in the global energy mix. Global installed photovoltaic capacity is expected to reach 520GW by 2024. Because photovoltaic modules are mostly used outdoors, dust inevitably accumulates on their surfaces. This dust reflects, absorbs, and scatters solar radiation, reducing power generation.

[0034] Dust accumulation has become a major factor affecting photovoltaic power generation efficiency. In arid and rainless regions, the decline in solar power generation caused by particle deposition is even more pronounced. Long-term dust accumulation can cause PV panel surfaces to fail and shorten their service life. Therefore, it is crucial to take measures to reduce particle accumulation and its negative impact on PV panel performance.

[0035] Currently, common PV panel cleaning methods, in addition to manual and natural dust removal, include mechanical methods, electrostatic spraying deposition (ESD), sonic methods, and coating methods. Compared to other dust removal methods, self-cleaning coatings offer superior effectiveness. They require no power consumption, resulting in low maintenance costs. Furthermore, they are easy to use and suitable for arid and water-scarce regions.

[0036] Specifically, the self-cleaning coating can form a hydrophobic surface. When rain falls on the self-cleaning coating in the photovoltaic module, it will gather into water droplets. The photovoltaic modules are all installed at an angle, so that the water droplets will flow away immediately, and at the same time wash away the dust on the surface of the photovoltaic module, thus achieving the self-cleaning function. A hydrophobic surface can refer to a surface with hydrophobicity. Hydrophobicity can be quantified by the contact angle. When a drop of liquid (such as water) is dropped on a solid surface, a contact angle is formed between the liquid and the solid surface. If the contact angle is greater than 90°, the solid surface is considered to be hydrophobic; the larger the contact angle, the stronger the hydrophobicity.

[0037] However, due to technical limitations in the manufacturing method of the self-cleaning coating in related technologies, it is difficult to improve the hydrophobicity and light transmittance of the self-cleaning coating obtained, which affects the power generation efficiency of the photovoltaic module.

[0038] In view of this, the present invention provides a method for preparing a photovoltaic module, which forms a self-cleaning coating on the surface of the photovoltaic module by infrared light irradiation, ensuring that the hydrophobic particles (such as titanium dioxide or zinc oxide, etc.) in the self-cleaning coating material are evenly dispersed, thereby improving the transmittance, and the infrared energy can be concentrated on the surface of the self-cleaning coating to form a dense hydrophobic layer (contact angle > 150°).

[0039] The preparation method of the photovoltaic module provided by the present invention is described in detail below with reference to the accompanying drawings.

[0040] Figure 1 FIG. 1 is a flow chart of a method for preparing a photovoltaic module according to an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0041] Step S101: providing an initial photovoltaic module.

[0042] The initial photovoltaic module includes a solar cell and an upper cover plate located on the solar cell.

[0043] Specifically, solar cells, made of semiconductor materials like silicon, are used to convert sunlight into electricity through the photoelectric effect, making them a key component in photovoltaic power generation. There can be one or more solar cells, connected in series or parallel to generate specific voltages and currents to meet varying power demands.

[0044] The top cover can be made of glass or transparent plastic with high light transmittance (e.g., greater than 90%), for example, tempered glass. The top cover protects other structures within the photovoltaic module, such as the solar cells, from external environmental influences such as wind, sand, rain, snow, and ultraviolet rays, while ensuring sufficient light transmission so that the solar cells can fully receive sunlight for photoelectric conversion.

[0045] For example, Figure 2 As shown, the initial photovoltaic module may include a backsheet 210, a first ethylene-vinyl acetate (EVA) layer 220, a solar cell 230, a second EVA layer 240, and an upper cover 250 stacked from bottom to top. In other words, the backsheet 210 is located at the bottom, the first EVA layer 220 may be located on the upper surface of the backsheet 210, the solar cell 230 may be located on the upper surface of the first EVA layer 220, the second EVA layer 240 may be located on the upper surface of the solar cell 230, and the upper cover 250 may be located on the upper surface of the second EVA layer 240.

[0046] Specifically, backsheet 210 can be made of a material with excellent weather resistance, insulation, and water resistance, such as a polyvinyl fluoride composite film. Backsheet 210 protects the solar cells and other internal components from the external environment, preventing moisture, dust, and other substances from entering the module. It also provides electrical insulation, ensuring the safe operation of the photovoltaic module.

[0047] The first EVA layer 220 and the second EVA layer 240 can both be hot melt adhesive films with good bonding properties and light transmittance. The first EVA layer 220 can be used to firmly bond the backboard 210 and the solar cell 230 together, and the second EVA layer 240 can be used to firmly bond the upper cover 250 and the solar cell 230 together. The first EVA layer 220 and the second EVA layer 240 can both also play a role of sealing and buffering, preventing water vapor, oxygen, etc. from entering the interior of the component, protecting the solar cell 230 from moisture and oxidation, and to a certain extent alleviating the impact of external stress on the solar cell 230, thereby improving the reliability and stability of the initial photovoltaic module.

[0048] Step S102: coating a self-cleaning coating material on a surface of the upper cover plate away from the solar cell.

[0049] Specifically, the self-cleaning coating material is used to make the formed self-cleaning coating have a hydrophobic surface. Exemplarily, the self-cleaning coating material may include nano-sized zinc oxide (ZnO) and / or nano-sized titanium dioxide (TiO2).

[0050] In some embodiments, the self-cleaning coating material may include polydimethylsiloxane (PDMS), hydrophobic nano-zinc oxide (ZnO), octyltriethoxysilane, methyltriethoxysilane (MTES), and n-hexane solvent. The PDMS content may be 8% to 12% by weight, the hydrophobic nano-ZnO content may be 1% to 3% by weight, the octyltriethoxysilane content may be 0.5% to 2% by weight, the MTES content may be 2% to 3% by weight, and the remainder may be n-hexane solvent.

[0051] Specifically, the mass percentage content of PDMS can be any value between 8% and 12%, for example, the mass percentage content of PDMS can be 8%, 9%, 10.5%, 11% or 12%, etc. The mass percentage content of hydrophobic nano-ZnO can be any value between 1% and 3%, for example, the mass percentage content of hydrophobic nano-ZnO can be 1%, 1.5%, 2% or 3%, etc. The mass percentage content of octyltriethoxysilane can be any value between 0.5% and 2%, for example, the mass percentage content of octyltriethoxysilane can be 0.5%, 1%, 1.2%, 1.8% or 2%, etc. The mass percentage content of MTES can be any value between 2% and 3%, for example, the mass percentage content of MTES can be 2%, 2.6% or 3%, etc. The mass percentage content of the n-hexane solvent varies based on the mass percentage content of PDMS, the mass percentage content of hydrophobic nano-ZnO, the mass percentage content of octyltriethoxysilane and the mass percentage content of MTES.

[0052] It should be understood that the mass percentage content of PDMS, hydrophobic nano-ZnO, octyltriethoxysilane, MTES and n-hexane solvent can be changed according to needs within the above-defined range. The present invention is not limited thereto, as long as the sum of the mass percentage content of PDMS, hydrophobic nano-ZnO, octyltriethoxysilane, MTES and n-hexane solvent is 100%.

[0053] For example, the self-cleaning coating material can be applied to the upper surface of the upper cover plate by spraying, spin coating, dipping, and scraping, etc. The parameters used in the coating can be set by the designer according to the requirements.

[0054] In some embodiments, before coating the self-cleaning coating material on the surface of the upper cover away from the solar cell (i.e., before step S102), the method for preparing the photovoltaic module also includes: cleaning and drying the upper cover to remove dust, oil and other impurities on the surface of the upper cover.

[0055] Specifically, the cleaning process may be to clean the upper cover plate with deionized water or a detergent, which may be a neutral glass cleaner or a detergent specifically used for cleaning photovoltaic modules; the drying process may refer to ventilating and drying the upper cover plate with a fan or a hair dryer.

[0056] In step S103 , the self-cleaning coating material is cured by infrared light to form a self-cleaning coating to obtain a photovoltaic module.

[0057] Specifically, the upper cover plate coated with the self-cleaning coating material can be placed in the working area of the infrared lighting device, and then the infrared lighting device is turned on to cure the self-cleaning coating material to form a Figure 3 The self-cleaning coating 260 is shown, thereby obtaining a photovoltaic module. The process parameters used in the infrared light irradiation method can be configured by the designer according to the requirements.

[0058] When using infrared light to cure self-cleaning coating materials, due to the long wavelength of infrared light (such as far-infrared light), it is easily absorbed by polar molecules (such as -OH, Si-O bonds) and nanomaterials (such as ZnO, TiO2 or silicon dioxide (SiO2)) on the surface of the self-cleaning coating material, and directly converted into heat energy, achieving rapid surface temperature increase (up to 80°C to 120°C within 1 to 3 seconds), while the internal temperature rise of the substrate (such as glass and metal) is small, avoiding thermal damage. Therefore, infrared radiation can act directly on the self-cleaning coating material without heating the entire workpiece or the environment, and energy consumption is reduced by 40% to 60% compared to hot air curing. At the same time, far-infrared heating can enhance the activity of photocatalysts such as ZnO. Even in the absence of ultraviolet light, thermal energy can promote the decomposition of pollutants (such as the oxidation reaction of oil stains).

[0059] Specifically, infrared light can be selectively absorbed by the vibration bonds (such as Zn-O and CH) of nano-ZnO or PDMS molecules in the self-cleaning coating material, promoting local cross-linking and reducing microcracks caused by overall thermal stress. At the same time, infrared radiation (such as far infrared (16.7 μm to 25 μm)) can complete curing in a graded manner, inhibiting the aggregation and phase separation of PDMS and nano-ZnO, ensuring uniform dispersion of nanoparticles, and improving light transmittance. Infrared energy is concentrated on the surface of the self-cleaning coating material to form a dense hydrophobic layer (contact angle > 150°), while maintaining a porous structure inside to balance mechanical properties and avoid the overall thickness affecting light transmittance.

[0060] For example, Figure 4 As shown, the photovoltaic module finally obtained may include a back sheet 210, a first EVA layer 220, a solar cell 230, a second EVA layer 240, an upper cover plate 250 and a self-cleaning coating 260 stacked in sequence.

[0061] Alternatively, as Figure 5As shown, the photovoltaic module may further include a frame 270 and a junction box 280. The frame 270 may be located around the solar cell 230, and the junction box 280 may be located on the surface of the back sheet 210 away from the first EVA layer 220 (such as the lower surface).

[0062] Specifically, frame 270 can be made of a metal material such as aluminum alloy, which has a certain strength and rigidity. Frame 270 is used to secure and protect the internal structure of the photovoltaic module, tightly connecting the upper cover, backplane and other components together to form an integrated frame structure. Junction box 280 is used to connect the circuit inside the photovoltaic module with the external circuit. Specifically, junction box 280 can collect the current generated by the solar cells and transmit it to the external circuit, while also preventing the current in the circuit from flowing in the opposite direction, thereby protecting the photovoltaic module and improving power generation efficiency.

[0063] In this embodiment, the self-cleaning coating material is cured using infrared light to form a self-cleaning coating, resulting in a super-hydrophobic surface. When rain falls on the photovoltaic modules, it gathers into water droplets. Since the photovoltaic modules are installed at an angle, the water droplets immediately flow away, simultaneously washing away any dust on the surface of the photovoltaic modules. This enhances the self-cleaning ability, prevents dust from affecting the power generation efficiency of the photovoltaic modules, and reduces maintenance costs. Furthermore, the self-cleaning coating has high light transmittance (greater than 90%) and UV resistance, further maintaining the high power generation efficiency of the photovoltaic modules.

[0064] Figure 6 FIG. 1 is a flow chart of another method for preparing a photovoltaic module according to an embodiment of the present invention. Figure 6 As shown, the method includes the following steps:

[0065] Step S601: providing an initial photovoltaic module.

[0066] For details, please see Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0067] Step S602 : coating a self-cleaning coating material on the surface of the upper cover plate away from the solar cell by a spraying robot.

[0068] Specifically, after obtaining the initial photovoltaic module, the initial photovoltaic module can be placed on the automatic spraying processing platform, and the initial photovoltaic module can be fixed on the processing platform by a fixing device such as vacuum adsorption. Figure 7 As shown, the self-cleaning coating material is continuously and evenly sprayed on the surface of the upper cover plate by the spraying robot 700, and then after curing treatment, a surface as shown in FIG. Figure 8The self-cleaning coating shown in the figure. The spraying parameters can be determined by the designer and configured in the controller of the spraying robot, so that the spraying robot can automatically spray the self-cleaning coating material on the surface of the upper cover after detecting the upper cover.

[0069] Among them, the self-cleaning coating material can be Figure 1 The self-cleaning coating material in the illustrated embodiment may also be a coating material already available on the market that has the same function (forming a hydrophobic surface).

[0070] In this embodiment, the self-cleaning coating material is sprayed onto the surface of the upper cover plate by a spraying robot. The spraying amount and spraying speed of the self-cleaning coating material can be precisely controlled, so that the self-cleaning coating material can be evenly coated on the surface of the upper cover plate. The uniform thickness of the self-cleaning coating helps ensure the consistency of the self-cleaning performance and avoids poor self-cleaning effect in certain areas due to uneven coating thickness.

[0071] In some optional embodiments, before coating the self-cleaning coating material on the surface of the upper cover plate away from the solar cell by a spray robot (i.e., before the above-mentioned step S602), the method for preparing the photovoltaic module further includes: determining the moving speed of the spray robot based on the thickness of the self-cleaning coating to be formed.

[0072] Optionally, the movement speed of the spray robot can be determined based on the first corresponding relationship and the thickness of the self-cleaning coating to be formed. The first corresponding relationship can be a corresponding relationship between the movement speed and the thickness, the first corresponding relationship can be a functional relationship, or a table, and the first comparative relationship can be determined based on experiments.

[0073] Alternatively, the moving speed of the spraying robot can be determined based on the thickness of the self-cleaning coating to be formed by the following formula (1):

[0074]

[0075] In formula (1), d represents the thickness of the self-cleaning coating to be formed, k represents the transfer efficiency of the self-cleaning coating material, Q represents the spray gun flow rate (mL / min), v represents the movement speed of the spray robot (cm / s), and w represents the spray width (cm). In the speed-film thickness theoretical relationship formula (1), the film thickness (d) is approximately inversely proportional to the spray speed (v). The transfer efficiency of the self-cleaning coating material is a constant and is related to the sol viscosity in the self-cleaning coating material and the adsorption of the substrate (top cover).

[0076] In this embodiment, the moving speed of the spraying robot is determined by a formula, so that the thickness of the self-cleaning coating can be more accurately controlled to the target thickness, avoiding secondary processing.

[0077] For example, the thickness of the self-cleaning coating to be formed may be in the range of 200 nm to 1 μm. In this case, the moving speed of the spraying robot may be in the range of 15 cm / s to 25 cm / s.

[0078] Specifically, the thickness of the self-cleaning coating to be formed can be any value between 200 nm and 1 μm, for example, the thickness of the self-cleaning coating to be formed can be 200 nm, 300 nm, 400 nm, 600 nm, 800 nm, 900 nm, or 1 μm, etc. The moving speed of the spraying robot can be any value between 15 cm / s and 25 cm / s, for example, the moving speed of the spraying robot can be 15 cm / s, 18 cm / s, 20 cm / s, or 25 cm / s, etc.

[0079] In this embodiment, the thickness of the self-cleaning coating is limited to between 200 nm and 1 μm, which can effectively balance super-hydrophobicity (such as a contact angle greater than 160°) and light transmittance. Specifically, if the self-cleaning coating is thicker, the path of light propagation in the self-cleaning coating becomes longer, and the probability of light being scattered and absorbed increases, resulting in reduced light transmittance. If the self-cleaning coating is thinner, it may not form sufficient microscopic roughness, making it difficult to achieve super-hydrophobicity.

[0080] In step S603 , the self-cleaning coating material is cured by infrared light to form a self-cleaning coating to obtain a photovoltaic module.

[0081] Exemplarily, the process parameters of the infrared light irradiation method include temperature, time and wavelength. The temperature ranges from 20° C. to 40° C., the time ranges from 5 min to 10 min, and the wavelength ranges from 16.7 μm to 25 μm.

[0082] Specifically, the temperature of the infrared light can be any value between 20° C. and 40° C., for example, the temperature of the infrared light can be 20° C., 25° C., 30° C., 36° C., or 40° C. The duration of the infrared light can be any value between 5 minutes and 10 minutes, for example, the duration of the infrared light can be 5 minutes, 6 minutes, 8 minutes, 9 minutes, or 10 minutes. The wavelength of the infrared light can be any value between 16.7 μm and 25 μm, for example, the wavelength of the infrared light can be 16.7 μm, 18 μm, 20 μm, or 25 μm.

[0083] In this embodiment, the temperature of the infrared light is limited to 20° C. to 40° C., the time is limited to 5 min to 10 min, and the wavelength is limited to 16.7 μm to 25 μm, so as to optimize the hydrophobicity and light transmittance of the self-cleaning coating.

[0084] The present invention further provides a photovoltaic module, which can be prepared by the method for preparing a photovoltaic module provided in any of the above embodiments.

[0085] For example, Figure 9 As shown, the self-cleaning coating 260 includes a plurality of sub-coatings 261 stacked from bottom to top, wherein the sub-coating 261 includes a bonding layer 2611 and a hydrophobic layer 2612 located on one side of the bonding layer 2611. The bonding layer 2611 at the bottom of the plurality of sub-coatings 261 is disposed on the upper cover plate 250. Figure 9 The self-cleaning coating 260 includes two sub-coatings 261 as an example, but the present invention is not limited thereto. For example, the self-cleaning coating 260 may also include three sub-coatings.

[0086] In other embodiments, the self-cleaning coating 260 may also consist of a sub-coating 261 .

[0087] Specifically, the materials of the bonding layer 2611 and the hydrophobic layer 2612 can both be the aforementioned self-cleaning coating materials, except that the proportions of the components in the self-cleaning coating materials used in the bonding layer 2611 and the hydrophobic layer 2612 are different.

[0088] For example, the ratio used in the bonding layer 2611 may include: the mass percentage content of PDMS can be 8%, the mass percentage content of hydrophobic nano-ZnO can be 1%, the mass percentage content of octyltriethoxysilane can be 0.5%, the mass percentage content of MTES can be 2%, and the rest is n-hexane solvent; the ratio used in the hydrophobic layer 2612 may include: the mass percentage content of PDMS can be 11%, the mass percentage content of hydrophobic nano-ZnO can be 2.5%, the mass percentage content of octyltriethoxysilane can be 2%, the mass percentage content of MTES can be 3%, and the rest is n-hexane solvent.

[0089] By adjusting the ratio of the components in the binding layer 2611 and the hydrophobic layer 2612, a synergistic effect is achieved between the binding layer 2611 and the hydrophobic layer 2612. The binding layer provides stable support and a firm attachment base for the hydrophobic layer, while the hydrophobic layer acts as a surface repellent for water and dirt. The two work together to enhance the overall performance of the self-cleaning coating, including its water resistance, antifouling properties, and durability.

[0090] For example, the thickness of the bonding layer 2611 may range from 100 nm to 150 nm, and the thickness of the hydrophobic layer 2612 may range from 100 nm to 800 nm. In other words, the thickness of the bonding layer 2611 may be any value between 100 nm and 150 nm, for example, the thickness of the bonding layer 2611 may be 100 nm, 110 nm, 120 nm, 135 nm, 140 nm, or 150 nm; the thickness of the hydrophobic layer 2612 may be any value between 100 nm and 800 nm, for example, the thickness of the hydrophobic layer 2612 may be 100 nm, 120 nm, 200 nm, 250 nm, 300 nm, 400 nm, 500 nm, 600 nm, or 800 nm.

[0091] In this embodiment, the self-cleaning coating 260 is formed by at least one sub-coating, which can improve the adhesion and hydrophobicity between the self-cleaning coating and the upper cover plate. Specifically, when the base coating material (the material of the bonding layer 2611) contacts the upper cover plate (tempered glass), since the surface of the tempered glass is rich in Si-OH, the Si-OH at the end of the PDMS can condense with it under the action of infrared light heating and curing to form Si-O-Si covalent bonds, thereby improving the adhesion of the self-cleaning coating to the tempered glass.

[0092] The self-cleaning coating on the photovoltaic module provided by the present invention is further described below through specific examples. These examples should not be construed as limiting the scope of protection claimed by the present invention.

[0093] Example 1

[0094] Step 1: 12% of PDMS, 3% of hydrophobic nano-ZnO, 2% of octyltriethoxysilane, 3% of methyltriethoxysilane, and 80% of n-hexane solvent are weighed and mixed uniformly to obtain a self-cleaning coating material;

[0095] Step 2: The obtained self-cleaning coating material is sprayed onto the surface of the upper cover plate (tempered glass) by a spraying robot, wherein the movement speed of the spraying robot is 15 cm / s, the flow rate of the spray gun is 10 mL / min, and the spraying width is 5 cm;

[0096] Step 3: Based on infrared light irradiation, the self-cleaning coating material is cured to form a self-cleaning coating, wherein the infrared light curing temperature is 25° C., the infrared light curing time is 5 minutes, and the infrared light wavelength is 20 μm.

[0097] Example 2

[0098] Compared with Example 1, the difference is that the infrared light curing time is 8 minutes.

[0099] Example 3

[0100] Compared with Example 1, the difference is that the infrared light curing time is 10 minutes.

[0101] Comparative Example 1

[0102] Compared with the first embodiment, the difference is that the self-cleaning coating material is cured by a traditional thermal curing method, wherein the traditional thermal curing method is an oven. It should be understood that the wavelength parameter is not included in the traditional thermal curing method.

[0103] Comparative Example 2

[0104] Compared with the second embodiment, the difference is that the self-cleaning coating material is cured by a traditional thermal curing method, wherein the traditional thermal curing method is an oven. It should be understood that the wavelength parameter is not included in the traditional thermal curing method.

[0105] Comparative Example 3

[0106] Compared with the third embodiment, the difference is that the self-cleaning coating material is cured by a traditional thermal curing method, wherein the traditional thermal curing method is an oven. It should be understood that the wavelength parameter is not included in the traditional thermal curing method.

[0107] Test Example 1

[0108] The self-cleaning coatings prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to performance tests, as follows:

[0109] Under irradiation with a wavelength of 550nm, the transmittance of the self-cleaning coating was tested by a spectrophotometer, and the applicable standard was GB / T 40415-2021. The adhesion of the self-cleaning coating was tested by the cross-cut method, and the applicable standard was ASTM D3359. The dustproof ability of the self-cleaning coating was tested by a dustproof test. The water resistance of the self-cleaning coating was tested by a water immersion test. The cleanliness of the self-cleaning coating was tested by an optical microscope. The water contact angle of the self-cleaning coating was tested by a contact angle meter.

[0110] The dustproof test is used to examine the self-cleaning coating's ability to resist wind and sand abrasion. Due to the many influencing factors in the actual environment, this paper uses the most representative parameters, namely a quartz sand concentration of 2.2g / m3, a wind speed of 25m / s, an ambient temperature of 50°C, a relative humidity of 30%, and a sample installation angle of 45°. After setting the above parameters, a 960-minute sand blowing test was conducted. After the test was completed, the samples were removed, rinsed with deionized water, and dried in a natural environment. The transmittance of the samples was tested separately, and the transmittance loss before and after the test (i.e., "transmittance before the experiment - transmittance after the experiment") was calculated.

[0111] Specifically, the dustproof ability includes four levels: very good, better, good and bad. When the attenuation rate A is greater than 2% (A>2%), it means that the dustproof ability is poor; when the attenuation rate is greater than 1.5% and the attenuation rate is less than or equal to 2% (1.5%<A≤2%), it means that the dustproof ability is good; when the attenuation rate is greater than 1% and the attenuation rate is less than or equal to 1.5% (1%<A≤1.5%), it means that the dustproof ability is better; when the attenuation rate is less than or equal to 1% (A≤1%), it means that the dustproof ability is very good.

[0112] The water immersion test involves placing the photovoltaic modules with self-cleaning coatings in water at a temperature of 40°C ± 5°C for 48 hours, and then conducting a water pressure test (applying a certain water pressure to the photovoltaic modules with self-cleaning coatings) to observe whether there is any leakage.

[0113] Among them, the waterproof ability is determined according to the ratio of the leakage area to the total area of the self-cleaning coating. The leakage conditions include good, good and bad. When the leakage area B is less than or equal to 5% (B≤5%), it indicates that the waterproof ability is good; when the leakage area is greater than 5% and the leakage area is less than 10% (5%<B<10%), it indicates that the waterproof ability is good; when the leakage area is greater than or equal to 10% (B≥10%), it indicates that the waterproof ability is bad.

[0114] The degree of cleanliness is constant according to the ratio of the polluted area to the total area. The degree of cleanliness includes four levels: unclean, relatively unclean, relatively clean and clean. Specifically, when the polluted area C is greater than 50% (C>50%), it indicates unclean; when the polluted area is less than or equal to 50% and the polluted area is greater than 30% (30%<C≤50%), it indicates relatively unclean; when the polluted area is less than or equal to 30% and the polluted area is greater than 20% (20%<C≤30%), it indicates relatively clean; when the polluted area is less than or equal to 20% (C≤20%), it indicates clean.

[0115] The test results can be shown in Table 1:

[0116] Table 1 Performance test results of Examples 1 to 3 and Comparative Examples 1 to 3

[0117] Light transmittance dust-proof water proof Cleanliness Water contact angle Adhesion Example 1 92％ very good better clean 160° 5B Example 2 94％ very good better clean 163° 5B Example 3 94％ very good good clean 164° 5B Comparative Example 1 83％ good good Cleaner 153° 4B Comparative Example 2 84％ very good better Cleaner 155° 5B Comparative Example 3 86％ good good Cleaner 156° 4B

[0118] As can be seen from Table 1, the infrared light processing method used in the present invention can make the self-cleaning coating have a transmittance of 92 to 94% at a wavelength of 550nm, while traditional thermal curing only has a transmittance of 83 to 86%. The self-cleaning coating has high transmittance and UV resistance, thereby maintaining the high power generation efficiency of photovoltaic modules and reducing maintenance costs. In addition, the infrared light processing method used in the present invention can make the contact angle of the self-cleaning coating reach 160° to 164°, showing strong hydrophobicity. Moreover, the adhesion of the self-cleaning coating is always at 5B, with better stability.

[0119] Example 4

[0120] Compared with the second embodiment, the difference is that the moving speed of the spraying robot is 10 cm / s.

[0121] Example 5

[0122] Same as Example 2

[0123] Example 6

[0124] Compared with the second embodiment, the difference is that the moving speed of the spraying robot is 20 cm / s.

[0125] Example 7

[0126] Compared with the second embodiment, the difference is that the moving speed of the spraying robot is 25 cm / s.

[0127] Test Example 2

[0128] The self-cleaning coatings prepared in Examples 4 to 7 were subjected to performance tests, as follows:

[0129] The thickness of the self-cleaning coating was tested by an ellipsometer; the transmittance of the self-cleaning coating was tested by a spectrophotometer under 550nm wavelength; and the water contact angle of the self-cleaning coating was tested by a contact angle meter. The test results can be shown in Table 2:

[0130] Table 2 Performance test results of Examples 4 to 7

[0131] Spraying speed Measured film thickness Water contact angle Light transmittance Example 4 10cm / s 1523nm 157° 89％ Example 5 15cm / s 989nm 162° 93％ Example 6 20cm / s 785nm 163° 95％ Example 7 25cm / s 522nm 164° 94％

[0132] As can be seen from Table 2, when the spraying speed is controlled between 15 cm / s and 25 cm / s, the film thickness of the self-cleaning coating changes more smoothly (500 nm-1000 nm) and the performance is stable (contact angle > 160° and transmittance > 93%).

[0133] Example 8

[0134] Compared with the second embodiment, the difference is that the infrared light curing temperature is 20°C.

[0135] Embodiment 9

[0136] Compared with the second embodiment, the difference is that the infrared light curing temperature is 30°C.

[0137] Example 10

[0138] Compared with the second embodiment, the difference is that the infrared light curing temperature is 40°C.

[0139] Comparative Example 4

[0140] Compared with the second embodiment, the difference is that the infrared light curing temperature is 10°C.

[0141] Comparative Example 5

[0142] Compared with the second embodiment, the difference is that the infrared light curing temperature is 15°C.

[0143] Comparative Example 6

[0144] Compared with the second embodiment, the difference is that the infrared light curing temperature is 50°C.

[0145] Test Example 3

[0146] The self-cleaning coatings prepared in Examples 8 to 10 and Comparative Examples 4 to 6 were subjected to performance tests, as follows:

[0147] The thickness of the self-cleaning coating was tested using an ellipsometer. The transmittance of the self-cleaning coating was tested using a spectrophotometer under 550nm wavelength. The adhesion of the self-cleaning coating was tested using the cross-hatch method, according to ASTM D3359. The water contact angle of the self-cleaning coating was tested using a contact angle meter. The test results are shown in Table 3.

[0148] Table 3 Performance test results of Examples 8 to 10 and Comparative Examples 4 to 6

[0149] Curing temperature Measured film thickness Water contact angle Light transmittance Adhesion Example 8 20℃ 1005nm 164° 92％ 5B Embodiment 9 30℃ 997nm 162° 92％ 5B Example 10 40℃ 964nm 163° 94％ 5B Comparative Example 4 10℃ 1223nm 157° 83％ 4B Comparative Example 5 15℃ 1208nm 160° 86％ 5B Comparative Example 6 50℃ 853nm 162° 95％ 5B

[0150] As can be seen from Table 3, when the infrared light curing temperature is controlled between 20°C and 40°C, the film thickness of the self-cleaning coating changes more smoothly (900nm-1000nm) and the performance is stable (contact angle >162° and transmittance >92%).

[0151] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships according to the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0152] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0153] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0154] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0155] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall all fall within the scope defined by the present invention.

Claims

1. A method for preparing a photovoltaic module, characterized in that: The method comprises: Providing an initial photovoltaic assembly, wherein the initial photovoltaic assembly includes a solar cell and an upper cover plate located on the solar cell; Coating a self-cleaning coating material on a surface of the upper cover plate away from the solar cell; The self-cleaning coating material is cured by infrared light to form a self-cleaning coating, thereby obtaining a photovoltaic module.

2. The method according to claim 1, characterized in that The process parameters of the infrared light irradiation method include temperature, time and wavelength. The temperature ranges from 20°C to 40°C, the time ranges from 5min to 10min, and the wavelength ranges from 16.7μm to 25μm.

3. The method according to claim 1, characterized in that The step of coating a self-cleaning coating material on a surface of the upper cover plate away from the solar cell comprises: The self-cleaning coating material is coated on the surface of the upper cover plate on the side away from the solar cell sheet by a spraying robot.

4. The method according to claim 3, characterized in that Before coating the self-cleaning coating material on the surface of the upper cover plate away from the solar cell by the spraying robot, the method further comprises: The moving speed of the spraying robot is determined based on the thickness of the self-cleaning coating to be formed.

5. The method according to claim 4, characterized in that The step of determining the movement speed of the spraying robot based on the thickness of the self-cleaning coating to be formed comprises: Based on the thickness of the self-cleaning coating to be formed, the moving speed of the spraying robot is determined by the following formula: Wherein, d represents the thickness of the self-cleaning coating to be formed, k represents the transfer efficiency of the self-cleaning coating material, Q represents the flow rate of the spray gun, v represents the moving speed of the spraying robot, and w represents the spraying width.

6. The method according to any one of claims 3 to 5, characterized in that The thickness of the self-cleaning coating ranges from 200 nm to 1 μm, and the moving speed of the spraying robot ranges from 15 cm / s to 25 cm / s.

7. The method according to any one of claims 1 to 5, characterized in that The self-cleaning coating material includes nano-scale zinc oxide and / or nano-scale titanium dioxide.

8. The method according to any one of claims 1 to 5, characterized in that The self-cleaning coating material includes polydimethylsiloxane, hydrophobic nano zinc oxide, octyltriethoxysilane, methyltriethoxysilane and n-hexane solvent, wherein the mass percentage content of the polydimethylsiloxane is 8% to 12%, the mass percentage content of the hydrophobic nano zinc oxide is 1% to 3%, the mass percentage content of the octyltriethoxysilane is 0.5% to 2%, the mass percentage content of the methyltriethoxysilane is 2% to 3%, and the rest is n-hexane solvent.

9. A photovoltaic module, characterized in that: The photovoltaic module is prepared by the method for preparing a photovoltaic module according to any one of claims 1 to 8.

10. The photovoltaic module according to claim 9, characterized in that: The self-cleaning coating includes a plurality of sub-coatings stacked from bottom to top, wherein the sub-coating includes a bonding layer and a hydrophobic layer located on one side surface of the bonding layer, and the bonding layer at the bottom of the plurality of sub-coatings is arranged on the upper cover plate.

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