Preparation method of self-cleaning film layer on surface of solar photovoltaic module

Abstract

The invention relates to the technical field of solar photovoltaic power generation assembly self-cleaning, and discloses a preparation method of a solar photovoltaic assembly surface self-cleaning film layer, which comprises the steps of titanium dioxide sol preparation, silicon dioxide sol preparation, composite ink construction, substrate pretreatment, coating process, gradient curing and photocatalytic activation. When the self-cleaning film layer is prepared, titanium dioxide and silicon dioxide composite sol is prepared through a specific process, molecular-level compounding is carried out, composite ink of a specific nano structure is formed, the uniformity and stability of film layer components are guaranteed, a foundation is laid for obtaining a high-performance self-cleaning function, and before the self-cleaning film layer is coated, the self-cleaning film layer is coated on the surface of the self-cleaning film layer. The surface of the photovoltaic glass base material is treated through the plasma in the specific atmosphere, the activity and energy level of the surface of the base material are improved, the binding force between the composite film layer and the base material is enhanced, and the film layer is prevented from being peeled off and falling off in the using process.

Description

Technical Field

[0001] This invention relates to the field of self-cleaning technology for solar photovoltaic power generation modules, specifically a method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module. Background Technology

[0002] Solar energy refers to the radiant energy of sunlight. As a clean energy source with abundant reserves, its utilization process is the most direct application of solar energy, with very little impact on the environment and climate. It has become the most popular research direction in the field of new energy in recent years. Solar photovoltaic modules are photoelectric conversion systems that use the photovoltaic effect to directly convert the energy in sunlight into electrical energy. The main components include aluminum alloy frame, ultra-white tempered glass, EVA for encapsulation, solar cells, and backsheet. There are many factors that affect the power generation of solar photovoltaic modules: the initial conversion efficiency and degradation of solar cells, the array installation tilt angle and azimuth angle, weather, dust accumulation on the modules, and shading.

[0003] Currently, there is a technical bottleneck in the preparation of self-cleaning film on the surface of solar photovoltaic modules: when forming functional film layers using traditional coating processes, uneven temperature field distribution during the curing stage leads to regional crystallization differences in the microstructure of the film layer surface. When the crystalline phase distribution on the film layer surface is abnormal, it will trigger a local light scattering enhancement effect, causing excessive fluctuations in the transmittance of the photovoltaic module.

[0004] Therefore, a method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module is proposed to solve the above problems. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module, thus solving the problems mentioned in the background section.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module, comprising the following steps:

[0009] S1. Preparation of titanium dioxide sol: Mix 200-220 mL of deionized water with a solution containing 20-22 mL of titanium isopropoxide and 8-10 mL of glacial acetic acid, stir for 2-2.5 hours, then add 2.4-2.6 mL of nitric acid; react in a water bath at 70-75℃ for 4 hours, then transfer to a hydrothermal reactor and treat at 180-220℃ for 12-14 hours; after cooling, add 2-2.2 mL of glacial acetic acid and sonicate the sol.

[0010] S2. Preparation of silica sol: Mix 20-22 mL of tetraethoxysilane, 15-18 mL of anhydrous ethanol and 5-6 mL of distilled water, add 0.2-0.25 mL of nitric acid catalyst, stir magnetically at 25-30℃ for 1-1.2 hours, then transfer to an environment of 5-8℃ for aging for 24-26 hours to form a transparent sol;

[0011] S3. Construction of composite ink: The silica sol obtained in S2 is added dropwise to the titanium dioxide sol in S1 at a volume ratio of 1:3-1:4. The mixture is magnetically stirred for 3-3.5 hours to achieve molecular-level composite. Then, 4-4.5 mL of Triton X-100 dispersant is added and the mixture is stirred for 3-3.5 hours to obtain titanium dioxide and silica composite ink.

[0012] S4. Substrate pretreatment: The photovoltaic glass surface is treated with an RF plasma cleaner for 5-8 minutes, with argon flow rate controlled at 20-25L / min, power at 200-250W, and treatment time of 6 minutes to achieve a surface energy of 70-75mN / m.

[0013] S5. Coating process: The ink is uniformly coated onto the substrate using a slot coater, with the slot gap controlled at 100μm and the coating speed at 1.0m / min, to form a wet film thickness of 55±5μm;

[0014] S6. Gradient curing: First stage: preheat at 80-85℃ for 12 minutes; second stage: cure at 120-125℃ for 30 minutes; third stage: heat treat at 180-200℃ for 45 minutes to form a 5-8μm film.

[0015] S7. Photocatalytic activation: Place the cured film in an ultraviolet chamber with a wavelength of 365nm and an intensity of 15-18mW / cm². 2 Continuous ultraviolet irradiation for 2.0-2.5 hours activates photocatalytic performance.

[0016] Preferably, the hydrothermal reaction temperature gradient in step S1 satisfies:

[0017]

[0018] Where T 实际 T represents the measured temperature of the reactor. 设定 Set the temperature for the program, where ΔT is the temperature overshoot value, t is the heating time, and τ is the temperature decay constant.

[0019] Specific control process: The temperature is increased to 180℃ at a rate of 5℃ / min, and after holding at the temperature for 4 hours, it is increased to 220℃ at a rate of 2℃ / min.

[0020] Preferably, the rheological properties of the composite ink described in step S3 satisfy:

[0021]

[0022] Where η is the ink viscosity, η0 is the reference viscosity, and E a The activation energy is R, the gas constant is T, and the operating temperature is T.

[0023] The ink has a zeta potential of +37mV and a particle size distribution of 35nm.

[0024] Preferably, the specific parameters for plasma treatment in step S4 include:

[0025] Radio frequency power 220W, processing time 6 minutes, argon to oxygen mixing ratio 4:1, chamber pressure 0.8mbar.

[0026] Preferably, the process parameters for slot coating in step S5 are as follows:

[0027] The coating speed is 1 m / min, the slit gap is 90 μm, and the ink supply flow rate is 17 mL / min.

[0028] Preferably, the gradient curing process in step S6 includes:

[0029] The first stage, at 80℃ for 12 minutes, ensures a solvent evaporation rate greater than 95%.

[0030] The second stage achieves molecular cross-linking at 125℃ for 30 minutes;

[0031] The third stage involves heating the film at 200℃ for 45 minutes to achieve a hardness of 6H.

[0032] Preferably, the photocatalytic efficiency of the self-cleaning film layer meets the following requirements:

[0033]

[0034] Where C0 is the initial concentration of methylene blue, C is the concentration at time t, k is the reaction rate constant, and t is the illumination time;

[0035] The membrane properties include: water contact angle less than 5°, surface resistivity 10 Ω·cm. 8 Ω / sq, methylene blue degradation rate greater than 98% in 2 hours.

[0036] Preferably, the solvent in steps S1 and S2 achieves a closed-loop cycle, specifically as follows:

[0037] The alcohol condensate produced by the hydrothermal reaction is dehydrated by molecular sieves and then reused in the preparation of silica sol.

[0038] Volatile solvents from the coating process are captured by a condensation recovery system, and components with a purity greater than 99% are returned to the initial mixture for preparation.

[0039] Preferably, the method further includes a film performance enhancement step:

[0040] 0.7 wt% of fluorosilane-modified nano-zinc oxide was added to the composite nano-ink. This additive was prepared by the following method:

[0041] Disperse nano zinc oxide in ethanol, and add tridecafluorooctyltriethoxysilane at a mass of 3% of zinc oxide.

[0042] The mixture was refluxed at 80°C for 4 hours, and then centrifuged and washed to obtain a hydrophobically modified reinforcing agent.

[0043] Preferably, the self-cleaning film layer performs the following functions on the photovoltaic module:

[0044] By controlling surface resistance, electrostatic dust accumulation is suppressed, reducing dust adhesion by more than 85%.

[0045] Photosensitive superhydrophilic properties improve rainwater flushing efficiency by 70%;

[0046] The yield of UV-activated hydroxyl radicals is greater than 40 nmol / (L·min);

[0047] Inhibiting the precipitation of glassy sodium calcium reduces the atomization rate by more than 90%.

[0048] (III) Beneficial Effects

[0049] Compared with the prior art, the present invention provides a method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module, which has the following beneficial effects:

[0050] 1. In this invention, during the preparation of the self-cleaning film, a titanium dioxide and silicon dioxide composite sol is prepared through a specific process and then molecularly composited to form a composite ink with a specific nanostructure. This ensures the uniformity and stability of the film composition and lays the foundation for obtaining high-performance self-cleaning function.

[0051] 2. In this invention, before coating the self-cleaning film, the surface of the photovoltaic glass substrate is treated with plasma in a specific atmosphere, which improves the activity and energy level of the substrate surface, enhances the bonding force between the composite film and the substrate, prevents the film from peeling and falling off during use, and ensures the long-term durability of the film.

[0052] 3. In this invention, when coating and curing the composite ink, a precise coating process is used to control the wet film thickness, and an optimized gradient temperature curing program is combined to ensure that the film layer can be formed uniformly and densely, avoiding cracks or defects caused by internal stress, and finally obtaining a self-cleaning functional film layer with uniform thickness and stable structure.

[0053] 4. In this invention, after the self-cleaning film is cured, it is irradiated with ultraviolet light of a specific wavelength and intensity to activate it, thereby stimulating the photocatalytic activity of the titanium dioxide component in the film. This ensures that the film has excellent self-cleaning and pollutant decomposition capabilities in the early stages of application, and improves the long-term cleanliness and power generation efficiency of the photovoltaic module surface. Attached Figure Description

[0054] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Please see Figure 1 The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module includes the following steps:

[0057] S1. Preparation of titanium dioxide sol: Mix 210 mL of deionized water with a solution containing 21 mL of titanium isopropoxide + 9 mL of glacial acetic acid, stir for 2 hours, then add 2.5 mL of nitric acid; react in a water bath at 70 °C for 4 hours, then transfer to a hydrothermal reactor and treat at 200 °C for 12 hours; after cooling, add 2 mL of glacial acetic acid and sonicate the sol.

[0058] S2. Preparation of silica sol: Mix 21 mL tetraethoxysilane, 17 mL anhydrous ethanol and 5.5 mL distilled water, add 0.23 mL nitric acid catalyst, stir magnetically at 28 °C for 1.1 hours, then transfer to 7 °C for aging for 24 hours to form a transparent sol;

[0059] S3. Construction of composite ink: The silica sol obtained in S2 was added dropwise to the titanium dioxide sol in S1 at a volume ratio of 1:4. The mixture was magnetically stirred for 3.5 hours to achieve molecular-level composite. Then, 4.3 mL of Triton X-100 dispersant was added and stirred for 3 hours to obtain a titanium dioxide and silica composite ink with a particle size distribution of 30 nm.

[0060] S4. Substrate pretreatment: The photovoltaic glass surface is treated with an RF plasma cleaner, with an argon flow rate of 23L / min, a power of 220W, and a treatment time of 6 minutes to achieve a surface energy of 72mN / m.

[0061] S5. Coating process: The ink is uniformly coated onto the substrate using a slot coater, with the slot gap controlled at 100μm and the coating speed at 1.0m / min, to form a wet film thickness of 55μm;

[0062] S6. Gradient curing: First stage: preheat at 83℃ for 12 minutes; second stage: cure at 123℃ for 30 minutes; third stage: heat treat at 190℃ for 45 minutes to form a 7μm film.

[0063] S7. Photocatalytic activation: The cured film layer is placed in an ultraviolet chamber with a wavelength of 365nm and an intensity of 17mW / cm². 2 Continuous ultraviolet irradiation for 2.3 hours activates photocatalytic performance.

[0064] The hydrothermal reaction temperature gradient in step S1 satisfies:

[0065]

[0066] Where T 实际 T represents the measured temperature of the reactor. 设定 Set the temperature for the program, where ΔT is the temperature overshoot value, t is the heating time, and τ is the temperature decay constant.

[0067] Specific control process: The temperature is increased to 180℃ at a rate of 5℃ / min, and after holding at the temperature for 4 hours, it is increased to 220℃ at a rate of 2℃ / min.

[0068] The rheological properties of the composite ink described in step S3 satisfy:

[0069]

[0070] Where η is the ink viscosity, η0 is the reference viscosity, and E a The activation energy is R, the gas constant is T, and the operating temperature is T.

[0071] The ink has a zeta potential of +37mV and a particle size distribution of 35nm.

[0072] The specific parameters for plasma treatment in step S4 include:

[0073] Radio frequency power 220W, processing time 6 minutes, argon to oxygen mixing ratio 4:1, chamber pressure 0.8mbar.

[0074] The process parameters for slot coating in step S5 are as follows:

[0075] The coating speed is 1 m / min, the slit gap is 90 μm, and the ink supply flow rate is 17 mL / min.

[0076] The gradient curing process in step S6 includes:

[0077] The first stage, at 83℃ for 12 minutes, ensures a solvent evaporation rate greater than 95%.

[0078] The second stage achieves molecular cross-linking at 123℃ for 30 minutes;

[0079] The third stage involves heating the film at 190℃ for 45 minutes to achieve a hardness of 6H.

[0080] The photocatalytic efficiency of the self-cleaning membrane meets the following requirements:

[0081]

[0082] Where C0 is the initial concentration of methylene blue, C is the concentration at time t, k is the reaction rate constant, and t is the illumination time;

[0083] The membrane properties include: water contact angle less than 5°, surface resistivity 10 Ω·cm. 8 Ω / sq, methylene blue degradation rate greater than 98% in 2 hours.

[0084] The solvent in steps S1 and S2 achieves a closed-loop cycle, specifically as follows:

[0085] The alcohol condensate produced by the hydrothermal reaction is dehydrated by molecular sieves and then reused in the preparation of silica sol.

[0086] Volatile solvents from the coating process are captured by a condensation recovery system, and components with a purity greater than 99% are returned to the initial mixture for preparation.

[0087] The method also includes a film performance enhancement step:

[0088] 0.7 wt% of fluorosilane-modified nano-zinc oxide was added to the composite nano-ink. This additive was prepared by the following method:

[0089] Disperse nano zinc oxide in ethanol, and add tridecafluorooctyltriethoxysilane at a mass of 3% of zinc oxide.

[0090] The mixture was refluxed at 80°C for 4 hours, and then centrifuged and washed to obtain a hydrophobically modified reinforcing agent.

[0091] The functions of self-cleaning films on photovoltaic modules include:

[0092] By controlling surface resistance, electrostatic dust accumulation is suppressed, reducing dust adhesion by more than 85%.

[0093] Photosensitive superhydrophilic properties improve rainwater flushing efficiency by 70%;

[0094] The yield of UV-activated hydroxyl radicals is greater than 40 nmol / (L·min);

[0095] Inhibiting the precipitation of glassy sodium calcium reduces the atomization rate by more than 90%.

[0096] Example 1: Implementation of Basic Processes

[0097] This embodiment specifically implements the preparation process of a self-cleaning film layer on the surface of a solar photovoltaic module. First, titanium dioxide sol is prepared: 210 mL of deionized water is added to a three-necked flask equipped with a mechanical stirrer. 21 mL of titanium isopropoxide and 9 mL of glacial acetic acid are premixed to form a transparent solution. This solution is slowly added to the water at a rate of 40 drops per minute through a constant-pressure funnel, and stirred at 300 rpm for 2.2 hours to form a milky white suspension. Then, 2.5 mL of nitric acid solution is added, and the mixture is transferred to a 70°C constant-temperature water bath and stirred continuously for 4 hours. The solution is observed to gradually transform into a translucent colloid. This colloid is transferred to a 200 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene (PTFE), heated to 200°C at a heating rate of 5°C / min, and reacted at this temperature for 13 hours. During the reaction, the high-pressure environment promotes the directional growth of anatase phase grains. After natural cooling to room temperature, 2.1 mL of glacial acetic acid is added, and the mixture is ultrasonically treated at a frequency of 40 kHz for 35 minutes to obtain a stable titanium dioxide sol with blue light scattering characteristics.

[0098] In the preparation of silica sol, 21 mL of tetraethoxysilane was measured and injected into a sealed container under a dry nitrogen atmosphere. 17 mL of anhydrous ethanol and 5.5 mL of distilled water were added to form a mixed system. 0.22 mL of nitric acid was added dropwise using a microsyringe to initiate a hydrolysis reaction. A condensation reaction was carried out for 1.1 hours under magnetic stirring at 28 °C. After observing an increase in solution viscosity, the solution was transferred to a 6 °C refrigerated environment for 25 hours of aging to form a colorless and transparent viscous silica sol. In the composite ink construction stage, the above silica sol and titanium dioxide sol were mixed in a light-shielded container at a volume ratio of 1:3.2. The mixture was first vigorously stirred at 800 rpm for 3.2 hours to achieve molecular chain entanglement and composite. Then, 4.3 mL of Triton X-100 surfactant was added, and the mixture was switched to low-speed stirring at 300 rpm for 3 hours to eliminate bubbles. Finally, a grayish-white composite ink with Newtonian fluid properties was obtained, and its viscosity was measured to be 9.2 cP at 25 °C.

[0099] Substrate treatment employed plasma-enhanced chemical vapor deposition (PECVD). The photovoltaic glass substrate was placed on a stage, and a mixture of argon and oxygen gas at a flow rate of 22 L / min and 5.5 L / min was introduced. The radio frequency power was set to 220 W, and surface activation was performed for 7 minutes under a vacuum of 0.8 mbar. After treatment, the water droplet contact angle on the substrate surface decreased from 72° to complete spreading. The coating process used a precision slot coating machine, with the coating head gap adjusted to 95 μm and a conveyor belt speed of 1.1 m / min. Uniform coating was applied, and the wet film thickness was kept stable at 53 μm under real-time monitoring using an online film thickness gauge. The gradient curing process was completed in a segmented temperature-controlled drying tunnel: the first zone was preheated at 82℃ for 13 minutes to achieve a solvent evaporation rate of 96%; the second zone was treated at 123℃ for 28 minutes to promote molecular cross-linking; and the third zone was heat-treated at 190℃ for 42 minutes to complete the ceramization transformation, ultimately forming a glassy film layer with a thickness of 6.5 μm. Finally, the component was placed in an ultraviolet activation chamber and activated using a mercury lamp light source with a peak wavelength of 365 nm at 16 mW / cm². 2 After continuous treatment under irradiation for 2.2 hours, the activated film layer achieved a transmittance of 93.7% in the visible light region.

[0100] Example 2: Implementation of the Enhanced Formulation

[0101] This embodiment introduces a reinforcing component into the basic formulation, focusing on improving the weather resistance of the film. In the composite ink construction stage, fluorosilane-modified nano-zinc oxide is prepared in advance: 10g of zinc oxide powder with a particle size of 80nm is dispersed in 200mL of anhydrous ethanol, and 0.3g of tridecafluorooctyltriethoxysilane is added. The mixture is refluxed in an oil bath at 80℃ for 4 hours, centrifuged, and washed three times with ethanol to obtain a hydrophobic reinforcing agent. This reinforcing agent is added at a ratio of 0.65wt% to the initially mixed titanium dioxide-silica composite system, and nanoscale dispersion is achieved by processing with a planetary ball mill at 450rpm for 1.5 hours.

[0102] The substrate pretreatment stage innovatively adopts a two-step activation method: first, argon plasma cleaning is performed to remove organic contaminants, followed by immersion in 2 mol / L sodium hydroxide solution for ultrasonic etching for 3 minutes to form a micron-level rough structure. The coating process is changed to a precision spin coating equipment with a set rotation speed of 850 rpm and an acceleration of 30 rpm / s. The film layer is accumulated and thickened by three gradient spin coatings. The gradient curing process adds an interface transition stage: 80℃ / 10min → 105℃ / 15min → 125℃ / 25min → 180℃ / 40min. This segmented program allows the organic components to be fully decomposed before ceramization.

[0103] The functional activation phase employs pulsed ultraviolet irradiation: the working cycle is set to 120 seconds of irradiation followed by a 30-second interval, with the total cumulative irradiance controlled at 15.3 kJ / cm². 2X-ray photoelectron spectroscopy analysis confirmed that the treatment resulted in a fluorine atomic concentration of 5.3% on the membrane surface. Water contact angle tests showed that the reinforced membrane had self-healing properties: the initial contact angle of 4.8° remained below 7.2° after 300 contamination-cleaning cycles. After 1000 hours of damp heat aging testing, the unreinforced membrane showed obvious white spots, while the haze increase of the membrane in this embodiment was only 0.8%.

[0104] Example 3: Implementation of Environmentally Friendly Processes

[0105] This embodiment implements a closed-loop green production process system. During the preparation of titanium dioxide sol, the volatile gases discharged from the hydrothermal reactor are diverted to a three-stage condensation system: the first stage uses a -5℃ ethylene glycol cooler to capture alcohols; the second stage uses a liquid nitrogen cryogenic trap to collect acetic acid; and the third stage uses a molecular sieve dehydration device to dry the gas. The recovered mixed alcohols are purified to 99.2% purity by distillation and used as a solvent substitute in the preparation of silica sol, which can reduce the consumption of fresh ethanol by 68% per batch.

[0106] The waste gas treatment system for the coating process consists of a cyclone separator and an activated carbon adsorption tower. The organic gases volatilized in the coating machine cavity first enter the cyclone separator at a flow rate of 12 m / s to remove solid particles. Then, they pass through the adsorption tower filled with coconut shell activated carbon at 20°C. The breakthrough curve test shows that the adsorption capacity for isopropanol reaches 295 mg / g. The saturated activated carbon is desorbed and regenerated by nitrogen at 120°C. The recovered organic solvent is purified by membrane separation and reused as the initial raw material, achieving a solvent recycling rate of 81%.

[0107] The wastewater treatment unit employs electrocatalytic oxidation technology: cleaning wastewater containing trace amounts of acid and surfactants is pumped into a reaction tank and treated using titanium-based iridium-tantalum electrodes at 8V. The hydroxyl radical yield reaches 3.2 μmol / L·min, and the COD value of the treated water is reduced from 850 mg / L to below 35 mg / L, meeting the industrial reclaimed water standard. After the implementation of the entire system, the VOC emissions per square meter of membrane layer are reduced from 125g to 6.3g, and the amount of hazardous waste generated is reduced by 91%.

[0108] Example 4: Implementation of Industrialized Mass Production

[0109] This embodiment demonstrates the implementation process of a megawatt-level production line. The core equipment includes: a fully automated sol preparation system, roll-to-roll coating lines, and a multi-segment temperature-controlled curing oven. The sol preparation system adopts a modular design: the titanium dioxide sol synthesis unit is equipped with four 500L reactors operating in parallel, and the hydrothermal reaction pressure is linked and controlled through a DCS system; the silica sol unit uses a tubular continuous hydrolyzer, and the material residence time is precisely controlled at 65 minutes.

[0110] The coating production line operates continuously at a speed of 1.8 meters per minute: the pretreatment section uses an atmospheric pressure plasma jetting device, with six sets of linear array nozzles at 7mm intervals to treat the surface of 1.2-meter wide photovoltaic glass; the slot coating head is equipped with a real-time viscosity compensation system, which monitors the ink viscosity through an online rheometer and dynamically adjusts the supply pressure to maintain a wet film thickness of 58μm; the downstream section is equipped with a three-stage suspended drying zone: the first zone uses 80℃ infrared heating to evaporate the solvent; the second zone uses 125℃ hot air circulation to solidify the film; and the third zone uses 195℃ far-infrared radiation to complete ceramic sintering.

[0111] The quality control system establishes four inspection points:

[0112] 1. The pretreatment monitoring station uses a laser confocal microscope to detect surface roughness;

[0113] 2. After coating, a thin-film interferometer is set up to measure the thickness distribution in real time;

[0114] 3. An automatic sampling robot is installed at the curing outlet to conduct cross-cut adhesion testing;

[0115] 4. In the finished product testing section, optical constants are measured using a spectroscopic ellipsometry, and photocatalytic activity is verified by the photoinduced hydrophilic response speed.

[0116] Data from continuous operation of the production line after its implementation shows that the maximum capacity of a single batch reaches 12,000 square meters of film layer, with an overall yield rate of 98.7%. The light transmittance of the film layer fluctuates within 0.8%. Photovoltaic modules with this film layer installed have been tested by a third-party certification body and have shown that the annual cleanliness maintenance rate in dusty environments is 32% higher than that of traditional products, and the overall power generation efficiency is increased by 3.7 percentage points.

[0117] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0118] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module, characterized in that: Includes the following steps: S1. Preparation of titanium dioxide sol: Mix 200-220 mL of deionized water with a solution containing 20-22 mL of titanium isopropoxide and 8-10 mL of glacial acetic acid, stir for 2-2.5 hours, then add 2.4-2.6 mL of nitric acid; react in a water bath at 70-75℃ for 4 hours, then transfer to a hydrothermal reactor and treat at 180-220℃ for 12-14 hours; after cooling, add 2-2.2 mL of glacial acetic acid and sonicate the sol. S2. Preparation of silica sol: Mix 20-22 mL of tetraethoxysilane, 15-18 mL of anhydrous ethanol and 5-6 mL of distilled water, add 0.2-0.25 mL of nitric acid catalyst, stir magnetically at 25-30℃ for 1-1.2 hours, then transfer to an environment of 5-8℃ for aging for 24-26 hours to form a transparent sol; S3. Construction of composite ink: The silica sol obtained in S2 is added dropwise to the titanium dioxide sol in S1 at a volume ratio of 1:3-1:

4. The mixture is magnetically stirred for 3-3.5 hours to achieve molecular-level composite. Then, 4-4.5 mL of Triton X-100 dispersant is added and the mixture is stirred for 3-3.5 hours to obtain titanium dioxide and silica composite ink. S4. Substrate pretreatment: The photovoltaic glass surface is treated with an RF plasma cleaner for 5-8 minutes, with argon flow rate controlled at 20-25L / min, power at 200-250W, and treatment time of 6 minutes to achieve a surface energy of 70-75mN / m. S5. Coating process: The ink is uniformly coated onto the substrate using a slot coater, with the slot gap controlled at 100μm and the coating speed at 1.0m / min, to form a wet film thickness of 55±5μm; S6. Gradient curing: First stage: preheat at 80-85℃ for 12 minutes; second stage: cure at 120-125℃ for 30 minutes; third stage: heat treat at 180-200℃ for 45 minutes to form a 5-8μm film. S7. Photocatalytic activation: Place the cured film in an ultraviolet chamber with a wavelength of 365nm and an intensity of 15-18mW / cm². 2 Continuous ultraviolet irradiation for 2.0-2.5 hours activates photocatalytic performance.

2. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The hydrothermal reaction temperature gradient in step S1 satisfies: Where T 实际 T represents the measured temperature of the reactor. 设定 Set the temperature for the program, where ΔT is the temperature overshoot value, t is the heating time, and τ is the temperature decay constant. Specific control process: The temperature is increased to 180℃ at a rate of 5℃ / min, and after holding at the temperature for 4 hours, it is increased to 220℃ at a rate of 2℃ / min.

3. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The rheological properties of the composite ink described in step S3 satisfy: Where η is the ink viscosity, η0 is the reference viscosity, and E a The activation energy is R, the gas constant is T, and the operating temperature is T. The ink has a zeta potential of +37mV and a particle size distribution of 35nm.

4. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The specific parameters for plasma treatment in step S4 include: Radio frequency power 220W, processing time 6 minutes, argon to oxygen mixing ratio 4:1, chamber pressure 0.8mbar.

5. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The process parameters for slot coating in step S5 are as follows: The coating speed is 1 m / min, the slit gap is 90 μm, and the ink supply flow rate is 17 mL / min.

6. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The gradient curing process in step S6 includes: The first stage, at 80℃ for 12 minutes, ensures a solvent evaporation rate greater than 95%. The second stage achieves molecular cross-linking at 125℃ for 30 minutes; The third stage involves heating the film at 200℃ for 45 minutes to achieve a hardness of 6H.

7. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The photocatalytic efficiency of the self-cleaning membrane layer meets the following requirements: Where C0 is the initial concentration of methylene blue, C is the concentration at time t, k is the reaction rate constant, and t is the illumination time; The membrane properties include: water contact angle less than 5°, surface resistivity 10 Ω·cm. 8 Ω / sq, methylene blue degradation rate greater than 98% in 2 hours.

8. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The solvent in steps S1 and S2 achieves a closed-loop cycle, specifically as follows: The alcohol condensate produced by the hydrothermal reaction is dehydrated by molecular sieves and then reused in the preparation of silica sol. Volatile solvents from the coating process are captured by a condensation recovery system, and components with a purity greater than 99% are returned to the initial mixture for preparation.

9. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The method further includes a film performance enhancement step: 0.7 wt% of fluorosilane-modified nano-zinc oxide was added to the composite nano-ink. This additive was prepared by the following method: Nano zinc oxide was dispersed in ethanol, and 3% (by mass) of tridecafluorooctyltriethoxysilane was added. The mixture was refluxed at 80°C for 4 hours, and then centrifuged and washed to obtain a hydrophobically modified reinforcing agent.

10. The method for preparing a self-cleaning film layer on the surface of a solar photovoltaic module according to claim 1, characterized in that: The self-cleaning film layer achieves the following functions on photovoltaic modules: Static dust accumulation is suppressed by surface resistance regulation; photoinduced superhydrophilicity improves rainwater flushing efficiency by 70%; the yield of hydroxyl radicals activated by ultraviolet light is greater than 40 nmol / (L·min); and the precipitation of glass sodium calcium is suppressed, resulting in a decrease in atomization rate of more than 90%.

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