Environmentally resistant photovoltaic glass and method of making the same

Abstract

The application discloses a kind of environment resistant photovoltaic glass preparation method, it is in the reflection film join boron nitride resistant agent, and select specific methoxyl content hydroxypropyl methyl cellulose as template agent and form by double spray head spraying.The photovoltaic glass prepared by the application realizes the antireflection of photovoltaic glass, has excellent mechanical strength and resistance, meets long-term service in the harsh environment of large temperature difference, windy and sandy.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic glass preparation technology, specifically relating to an environmentally resistant photovoltaic glass and its preparation method, as well as its application in high-performance architectural glass in building-integrated photovoltaics. Background Technology

[0002] Solar power generation, as an important component of new energy development, has developed rapidly in recent years. Photovoltaic glass, as a key component of solar photovoltaic modules, has a crucial impact on the industry's development. In the early stages of development, low-iron ultra-white glass was widely used as the front-side encapsulation material for photovoltaic modules. It has relatively high transmittance, strong weather resistance, and mechanical strength. However, its refractive index of about 1.52 is mismatched with the refractive index of air of about 1.0, leading to Fresnel reflection and reducing the photoelectric conversion efficiency of photovoltaic modules.

[0003] In recent years, with the progress of photovoltaic glass research in laboratories and industries, a thin film material with a low refractive index, namely a photovoltaic glass antireflective coating, has been designed to coat the glass surface. This film is an effective way to increase the light transmittance (anti-reflection) or reduce the reflection (anti-reflection) of photovoltaic glass. However, in practical applications, the antireflective coating is highly susceptible to mechanical wear and damage from harsh environments, affecting the lifespan of the photovoltaic glass and increasing operating costs.

[0004] For example, Chinese patent CN119954406A, "Ultra-high Transmittance and Anti-reflection Multifunctional Coated Photovoltaic Glass and its Preparation Method," provides a technology: a high transmittance and anti-reflection coating comprising a silicon dioxide layer, a titanium dioxide layer, and a nanomaterial layer is deposited on a photovoltaic glass substrate. This technical solution has a relatively complex film structure, and the multi-layer stacking preparation process increases production costs and process control difficulty. Furthermore, this coated photovoltaic glass primarily addresses the issue of improving light transmittance, posing a significant challenge to the long-term weather resistance stability of the film layer in complex outdoor environments.

[0005] Chinese patent CN118006218B discloses a gain liquid for solar glass antireflective film, its preparation method, and its application. The gain liquid comprises a pre-prepared solution and a volatilization inhibitor. The raw materials for preparing the pre-prepared solution include silicate ester, diluent, water, and catalyst, with a mass ratio of silicate ester, diluent, water, and catalyst of 10-25:25-55:5-15:0.1-1.0. This technical solution involves further gain treatment on top of the existing reflective film, increasing the number of process steps and the difficulty of production control. Furthermore, the compatibility and adhesion between the gain liquid and the original film layer often suffer serious drawbacks under harsh operating environments.

[0006] In 2023, Adam M. Law et al. published "The performance and durability of anti-reflection coatings for solar module cover glass" in the journal *Solar Energy*. This technical report pointed out that recent research shows that commonly used silica coatings are susceptible to wear, chemical corrosion, and humidity-related degradation. These coatings are also hydrophilic, have high surface energy, and strong adhesion to stains. The report explored multilayer metal oxide coatings composed of alternating layers of dielectric metal oxides (such as zirconium dioxide and silica) as a potential alternative to porous silica. However, this was only a prediction of industry development trends, and no effective and feasible technical means were provided.

[0007] Photovoltaic equipment installed in special regions, such as the deserts of western my country (dry, with little rain, frequent sandstorms, and large temperature differences between day and night), has high requirements for self-cleaning and dust prevention, as well as high requirements for its own strength and environmental tolerance. To address the shortcomings of the industry's technology, there is an urgent need for an environmentally resistant photovoltaic glass and its manufacturing method, which would enable the large-scale application of environmentally resistant photovoltaic glass and achieve extended lifespan and reduced costs. Summary of the Invention

[0008] This invention addresses the shortcomings of existing silicon dioxide coatings in photovoltaic glass, such as rapid optical performance degradation during long-term outdoor service, easy damage to the film layer, and insufficient self-cleaning ability.

[0009] This invention introduces boron nitride into the coating system and utilizes its intrinsic properties such as high hardness, high chemical stability, high refractive index (about 2.0) and wide gap (about 6.2 eV) to design a gradient distribution with the bottom layer enriched and the surface layer sparse within the same coating, thereby maximizing the performance of the reflective film.

[0010] Furthermore, the technical solution of this invention provides hydroxypropyl methylcellulose (HPMC) as a template agent. Compared with other template agents, HPMC, as a green polymer template agent, has multiple functions such as thickening, dispersing, film formation and bonding. It can effectively improve the coating uniformity of the coating solution and promote the formation of a dense and continuous film structure. In particular, HPMC with high methoxy content exhibits better hydrophobic properties, further enhancing the interfacial bonding strength between the film layer and the glass substrate and the self-cleaning function.

[0011] This invention is achieved through the following means:

[0012] In a first aspect, the present invention provides a method for preparing environmentally resistant photovoltaic glass, which comprises the following steps:

[0013] S1, preparation of tolerant

[0014] Boron nitride, a resistance agent, was subjected to high-energy ball milling with zirconia balls as the ball-to-material medium. The ball-to-material weight ratio was 20-50:1, the rotation speed was 500-1000 rpm, and the ball-to-material time was 6-8 hours to obtain boron nitride nanopowder.

[0015] Boron nitride nanopowder was added to an ethanol aqueous solution, a silane coupling agent was added, and the mixture was stirred and refluxed at 50-80℃ for 3 hours. After centrifugation, washing, and drying, the resistant agent powder was obtained.

[0016] S2, Preparation of Coating Solution

[0017] Tetraethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid are mixed and stirred for 2-4 hours to obtain a transparent and homogeneous silica sol.

[0018] Add hydroxypropyl methylcellulose template agent to the silica gel solution, stir for 10-30 minutes, add the resistance agent powder and nano-silica hollow spheres with a weight ratio of 5:1, then add the silane coupling agent, ultrasonically disperse for 30-60 minutes, and adjust the pH value to 4-6 using acetic acid or ammonia water to obtain coating solution A.

[0019] The weight ratio of the resistance agent powder to the nano-silica hollow spheres was adjusted to 1:5, and the same procedure was followed to obtain coating solution B.

[0020] S3, Coating

[0021] Place the cleaned photovoltaic glass substrate on the spraying station, start the two-component spraying system, with the spray gun connected to coating solution A in front, spraying amount of 5-10mL / m²; coating solution B in the back, spraying amount of 20-30mL / m².

[0022] S4, Heat Treatment

[0023] The coated photovoltaic glass is pre-dried at 100-150℃ for 1-10 minutes, then heat-treated in a tempering furnace at 680-720℃ for 3-5 minutes, and finally tempered by air cooling to obtain the finished photovoltaic glass.

[0024] Furthermore, in the preparation method of the photovoltaic glass, the boron nitride in the S1 resistance agent is any one of hexagonal boron nitride, cubic boron nitride, wurtzite boron nitride, and rhombohedral boron nitride. As a preferred option, cubic boron nitride is preferred. Its zincblende face-centered cubic structure (similar to the crystal structure of diamond) gives it significant ultra-hardness, excellent thermal properties, and chemical stability. At the same time, cubic boron nitride is the material with the largest bandgap among third-generation semiconductors, exhibiting good optical transmittance over a wide range from ultraviolet to infrared. This characteristic ensures that when it is introduced into the coating layer as a reinforcing phase, it will not have a significant negative impact on the optical anti-reflection effect of the film layer, thus balancing the dual requirements of mechanical reinforcement and optical performance.

[0025] The silane coupling agent used in the preparation of the S1 resistance agent and the formulation of the S2 coating solution is either aminosilane coupling agent KH-550 or epoxysilane coupling agent KH-560.

[0026] Furthermore, in the preparation method of the photovoltaic glass, the silica sol in the S2 coating solution comprises, by weight, the following components:

[0027] 20-40 parts of tetraethyl orthosilicate

[0028] 60-100 parts of anhydrous ethanol

[0029] 6-15 parts deionized water

[0030] 0.1-1 parts of dilute hydrochloric acid; the dilute hydrochloric acid is a 1 mol / L aqueous solution of hydrochloric acid.

[0031] The preferred formulation consists of: 30 parts tetraethyl orthosilicate, 80 parts anhydrous ethanol, 10 parts deionized water, and 0.5 parts dilute hydrochloric acid (1 mol / L).

[0032] Furthermore, in the preparation method of the photovoltaic glass, the formulation of coating solution A in the S2 coating solution consists of the following components by weight:

[0033] 30-60 parts of silica sol

[0034] Hydroxypropyl methylcellulose 0.5-3 parts

[0035] 5-15 parts of tolerance agent powder

[0036] 1-3 parts of nano-silica hollow spheres

[0037] 1-5 parts of silane coupling agent

[0038] The hydroxypropyl methylcellulose has a viscosity of 400-1500 mPa·s, and the nano-silica hollow spheres have a particle size of 20-100 nm.

[0039] The preferred formulation consists of: 45 parts silica sol, 1.5 parts hydroxypropyl methylcellulose, 10 parts cubic boron nitride powder, 2 parts nano-silica hollow spheres, and 3 parts silane coupling agent.

[0040] Furthermore, in the preparation method of the photovoltaic glass, the formulation of coating solution B in the S2 coating solution consists of the following components by weight:

[0041] 30-60 parts of silica sol

[0042] Hydroxypropyl methylcellulose 0.5-3 parts

[0043] 1-3 parts of tolerant powder

[0044] 5-15 parts of nano-silica hollow spheres

[0045] 1-5 parts of silane coupling agent

[0046] The viscosity of the hydroxypropyl methylcellulose is 400-1500 mPa·s, which is the viscosity value of its 2% aqueous solution measured at 20℃. The particle size of the nano-silica hollow spheres is 20-100 nm.

[0047] The preferred formulation consists of: 45 parts silica sol, 1.5 parts hydroxypropyl methylcellulose, 2 parts cubic boron nitride powder, 10 parts nano-silica hollow spheres, and 3 parts silane coupling agent.

[0048] Furthermore, in the S3 coating process of the photovoltaic glass preparation method, the spraying parameters of the two-component spraying system are: spraying pressure 0.3-0.5 MPa, vertical distance between the spray gun and the substrate 15-25 cm, and spray gun moving speed 30-60 mm / s; the distance between the two spray guns is 5-10 cm. As a preferred embodiment, the spray gun connected to coating solution A is in front, with a spraying amount of 7 mL / m²; coating solution B is in the back, with a spraying amount of 25 mL / m². As the most preferred embodiment, on the one hand, the lower spraying amount of the bottom layer (7 mL / m²) is beneficial for forming an ultra-thin, uniform boron nitride-enriched anchoring layer, fully utilizing the interface enhancement effect of boron nitride while avoiding optical loss caused by excessive aggregation; on the other hand, the higher spraying amount of the surface layer (25 mL / m²) ensures that the anti-reflection functional layer has sufficient film thickness to achieve the ideal broadband anti-reflection effect. The coordinated matching of the front and rear coating amounts ensures that the film layer achieves excellent mechanical strength and weather resistance while maintaining high visible light transmittance and good film layer uniformity.

[0049] Secondly, the present invention also provides a photovoltaic glass, which is prepared by the above-described preparation method.

[0050] Thirdly, the present invention also provides the application of this photovoltaic glass in the cover plate of a photovoltaic module. Preferably, the photovoltaic module is installed in arid, low-rainfall, dusty, and diurnal temperature range desert areas or areas with heavy environmental pollution and prone to acid rain, and has a longer service life and higher performance.

[0051] Fourthly, the present invention also provides the application of the photovoltaic glass in high-performance building glass integrated with photovoltaics, wherein the high-performance building glass is a building glass door and window, a building glass curtain wall, a building glass skylight, a building glass partition, or an energy-saving insulated glass.

[0052] The beneficial effects of this invention compared to the prior art are as follows:

[0053] 1. The boron nitride raw material in the reflective film of this invention has super-hardness second only to diamond, excellent thermal conductivity and chemical inertness, which can significantly improve the wear resistance of the film and resist the erosion and wear of sand and dust particles without sacrificing optical performance; hydroxypropyl methylcellulose (HPMC) is selected as a template agent, which has multiple functions of thickening, dispersing and film formation, which can effectively prevent boron nitride agglomeration and form a dense and continuous film structure. At the same time, the photovoltaic glass prepared by using HPMC with a specific methoxy content has higher hydrophobic properties.

[0054] 2. This invention constructs a gradient distribution structure with boron nitride enrichment in the bottom layer and sparse boron nitride on the surface layer through dual-nozzle spraying. The bottom layer utilizes the ultra-hard properties of boron nitride to enhance the scratch resistance of the film layer, while the boron nitride can anchor silica sol particles, improving the adhesion between the film layer and the glass substrate. The boron nitride content in the surface layer is controlled to avoid a decrease in light transmittance due to high refractive index, thus balancing mechanical enhancement and optical anti-reflection performance.

[0055] 3. The environmentally resistant photovoltaic glass provided by this invention effectively overcomes the shortcomings of existing photovoltaic coated glass, such as difficulty in achieving both anti-reflection and weather resistance, and easy wear and aging of the coating. The photovoltaic glass prepared has high light transmittance, excellent mechanical strength and weather resistance, and can meet the long-term service requirements in harsh environments with large temperature differences and frequent sandstorms. It is suitable for high-efficiency photovoltaic modules and building-integrated photovoltaics. Attached Figure Description

[0056] Figure 1 The manufacturing process of environmentally resistant photovoltaic glass;

[0057] Figure 2 The electron microscope image of the sample from Example 1 after aging in Experiment 4;

[0058] Figure 3 Electron micrograph of Comparative Example 1 sample after aging in Experiment 4; Detailed Implementation

[0059] The following description illustrates exemplary embodiments of the present invention, including various details to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. Similarly, for clarity and brevity, descriptions of well-known functions, operations, and structures are omitted in the following description.

[0060] Unless otherwise defined, the technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. While similar or identical methods and materials may be applied in experimental or practical applications, the present invention describes materials and methods hereinafter. In case of conflict, the definitions included herein shall prevail.

[0061] Unless otherwise specified, all experiments in the following experiments were conducted under standard conditions or conditions recommended by the manufacturer. Raw materials or enzymes, and reagents or instruments whose manufacturers are not specified, are all commercially available products. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight. Unless otherwise specified, all materials in this invention are commercially available chemicals without significantly affecting the overall effect of the formulation.

[0062] Example 1: Preparation of photovoltaic glass containing a resistance agent

[0063] formula:

[0064] Silica sol:

[0065]

[0066] Coating solution A:

[0067]

[0068] Coating solution B:

[0069]

[0070] The viscosity and methoxy content of hydroxypropyl methylcellulose were determined according to Part IV of the 2025 edition of the Chinese Pharmacopoeia.

[0071] Preparation process:

[0072] S1, preparation of tolerant

[0073] Cubic boron nitride was subjected to high-energy spheroidizing with zirconia spheres as the spheroidizing medium. 7 kg of zirconia spheres and 0.2 kg of cubic boron nitride were added, the rotation speed was 800 rpm, and the spheroidizing time was 7 hours to obtain boron nitride nanopowder.

[0074] Cubic boron nitride nanoparticles were added to 1.6 kg of 75% ethanol solution, and 0.2 kg of silane coupling agent, namely aminosilane coupling agent KH-550, were added. The mixture was stirred and refluxed at 70°C for 3 hours, and then centrifuged, washed with anhydrous ethanol, and dried with hot air at 80°C to obtain the resistant agent powder.

[0075] S2, Preparation of Coating Solution

[0076] Mix the prescribed amounts of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and 1 mol / L dilute hydrochloric acid, and stir for 3 hours to obtain a transparent and homogeneous silica sol for later use.

[0077] Coating solution A: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 20 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, namely aminosilane coupling agent KH-550. Disperse ultrasonically at 4000W for 45 minutes, and adjust the pH to 5.0 using acetic acid or amino acid solution. The coating solution is then obtained.

[0078] Coating solution B: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 20 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, namely aminosilane coupling agent KH-550. Disperse ultrasonically at 4000W for 45 minutes, and adjust the pH to 5.0 using acetic acid or amino acid solution. The coating solution is then obtained.

[0079] S3, Coating

[0080] Glass substrate treatment: The ultra-white glass is sequentially cleaned with acetone, ethanol and deionized water in a water bath using ultrasonic cleaning; then, nitrogen is used to blow away residual liquid on the substrate surface and it is transferred to an oven for thorough drying; finally, the dried substrate is sent to a plasma cleaning device and its surface is activated under an argon atmosphere to obtain a clean pretreated glass substrate with high surface energy.

[0081] Place the cleaned photovoltaic glass substrate on the spraying station, select a two-component spraying system, with the spray gun connected to coating solution A in front and the spraying volume 7ml / ㎡, and the spray gun connected to coating solution B in the back and the spraying volume 25ml / ㎡.

[0082] S4, Heat Treatment

[0083] The S3-coated photovoltaic glass was pre-dried at 125°C for 5 minutes, then heat-treated in a tempering furnace at 700°C for 4 minutes, and finally tempered by air cooling to obtain the finished photovoltaic glass.

[0084] Example 2: Preparation of photovoltaic glass containing a resistance agent

[0085] formula:

[0086] Same as in Example 1.

[0087] Preparation process:

[0088] S1, preparation of tolerant

[0089] Cubic boron nitride was subjected to high-energy spheroidizing with zirconia spheres as the spheroidizing medium. 4 kg of zirconia spheres and 0.2 kg of cubic boron nitride were added, the rotation speed was 1000 rpm, and the spheroidizing time was 8 hours to obtain boron nitride nanopowder.

[0090] Cubic boron nitride nanoparticles were added to 1 kg of 75% ethanol solution, and 0.1 kg of silane coupling agent, namely aminoepoxysilane coupling agent KH-560, were added. The mixture was stirred and refluxed at 55°C for 3 hours, and then centrifuged, washed with anhydrous ethanol, and dried with hot air at 80°C to obtain the resistant agent powder.

[0091] S2, Preparation of Coating Solution

[0092] Mix the prescribed amounts of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and 1 mol / L dilute hydrochloric acid, and stir for 2 hours to obtain a transparent and homogeneous silica sol for later use.

[0093] Coating solution A: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 10 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, namely the aminoepoxysilane coupling agent KH-560. Disperse the mixture by ultrasonication at 5000W for 30 minutes. Adjust the pH value to 4.3 using acetic acid or amino acid solution to obtain the final product.

[0094] Coating solution B: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 10 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, namely the aminoepoxysilane coupling agent KH-560. Disperse the mixture by ultrasonication at 5000W for 30 minutes. Adjust the pH value to 4.3 using acetic acid or amino acid solution to obtain the final product.

[0095] S3, Coating

[0096] Glass substrate treatment: The ultra-white glass is sequentially cleaned with acetone, ethanol and deionized water in a water bath using ultrasonic cleaning; then, nitrogen is used to blow away residual liquid on the substrate surface and it is transferred to an oven for thorough drying; finally, the dried substrate is sent to a plasma cleaning device and its surface is activated under an argon atmosphere to obtain a clean pretreated glass substrate with high surface energy.

[0097] Place the cleaned photovoltaic glass substrate on the spraying station, select a two-component spraying system, with the spray gun connected to coating solution A in front and the spraying volume 5ml / ㎡, and the spray gun connected to coating solution B in the back and the spraying volume 20ml / ㎡.

[0098] S4, Heat Treatment

[0099] The S3-coated photovoltaic glass was pre-dried at 105°C for 10 minutes, then heat-treated in a tempering furnace at 720°C for 3 minutes, and finally tempered by air cooling to obtain the finished photovoltaic glass.

[0100] Example 3: Preparation of photovoltaic glass containing a resistance agent

[0101] formula:

[0102] Same as in Example 1.

[0103] Preparation process:

[0104] S1, preparation of tolerant

[0105] Cubic boron nitride was subjected to high-energy spheroidizing with zirconia spheres as the spheroidizing medium. 9 kg of zirconia spheres and 0.2 kg of cubic boron nitride were added, the rotation speed was 600 rpm, and the spheroidizing time was 6 hours to obtain boron nitride nanopowder.

[0106] Cubic boron nitride nanoparticles were added to 2 kg of 75% ethanol solution, and 0.3 kg of silane coupling agent, namely aminoepoxysilane coupling agent KH-560, were added. The mixture was stirred and refluxed at 80°C for 3 hours, and then centrifuged, washed with anhydrous ethanol, and dried with hot air at 80°C to obtain the resistant agent powder.

[0107] S2, Preparation of Coating Solution

[0108] Mix the prescribed amounts of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and 1 mol / L dilute hydrochloric acid, and stir for 4 hours to obtain a transparent and homogeneous silica sol for later use.

[0109] Coating solution A: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 30 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, i.e., aminosilane coupling agent KH-550. Disperse ultrasonically at 3000W for 60 minutes, and adjust the pH to 6.0 using acetic acid or amino acid solution. The coating solution is then obtained.

[0110] Coating solution B: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 30 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, namely aminosilane coupling agent KH-550. Disperse ultrasonically at 3000W for 60 minutes, and adjust the pH to 6.0 using acetic acid or amino acid solution. The coating solution is then obtained.

[0111] S3, Coating

[0112] Glass substrate treatment: The ultra-white glass is sequentially cleaned with acetone, ethanol and deionized water in a water bath using ultrasonic cleaning; then, nitrogen is used to blow away residual liquid on the substrate surface and it is transferred to an oven for thorough drying; finally, the dried substrate is sent to a plasma cleaning device and its surface is activated under an argon atmosphere to obtain a clean pretreated glass substrate with high surface energy.

[0113] Place the cleaned photovoltaic glass substrate on the spraying station, select a two-component spraying system, with the spray gun connected to coating solution A in front and the spraying volume 9 ml / ㎡, and the spray gun connected to coating solution B in the back and the spraying volume 30 ml / ㎡.

[0114] S4, Heat Treatment

[0115] The S3-coated photovoltaic glass was pre-dried at 150°C for 3 minutes, then heat-treated in a tempering furnace at 680°C for 5 minutes, and finally tempered by air cooling to obtain the finished photovoltaic glass.

[0116] Example 4: Preparation of photovoltaic glass containing a resistance agent

[0117] formula:

[0118] Same as in Example 1.

[0119] Preparation process:

[0120] Except for S3 and the coating amount during coating, the rest are the same as in Example 1; in Example 4, the spraying amount of spraying liquid A is 3 ml / ㎡ and the spraying amount of spraying liquid B is 12 ml / ㎡.

[0121] Example 5: Preparation of photovoltaic glass containing a resistance agent

[0122] formula:

[0123] Same as in Example 1.

[0124] Preparation process:

[0125] Except for S3 and the coating amount during coating, the rest are the same as in Example 1; in Example 4, the spraying amount of spraying liquid A is 15 ml / ㎡, and the spraying amount of spraying liquid B is 45 ml / ㎡.

[0126] Comparative Example 1: Preparation of boron nitride photovoltaic glass without the tolerance agent

[0127] formula:

[0128] Silica sol:

[0129]

[0130] Coating solution A:

[0131]

[0132] Coating solution B:

[0133]

[0134] Preparation process:

[0135] S1, preparation of tolerant

[0136] We directly purchased commercially available silica nanoparticle powder with a particle size of 100nm.

[0137] Silica nanoparticles were added to 1.6 kg of 75% ethanol solution, and 0.2 kg of silane coupling agent, namely aminosilane coupling agent KH-550, were added. The mixture was stirred and refluxed at 70°C for 3 hours, and then centrifuged, washed with anhydrous ethanol, and dried with hot air at 80°C to obtain the resistant silica powder.

[0138] S2, Preparation of coating solution; S3, Coating; S4, Heat treatment.

[0139] Same as in Example 1.

[0140] Comparative Example 2: Preparation of single-layer sprayed photovoltaic glass containing resistance agent

[0141] formula:

[0142] Silica sol:

[0143]

[0144] Coating solution:

[0145]

[0146] Preparation process:

[0147] S1, preparation of tolerant

[0148] Same as in Example 1.

[0149] S2, Preparation of Coating Solution

[0150] Mix the prescribed amounts of tetraethyl orthosilicate, anhydrous ethanol, deionized water, and 1 mol / L dilute hydrochloric acid, and stir for 3 hours to obtain a transparent and homogeneous silica sol for later use.

[0151] Coating solution: Add hydroxypropyl methylcellulose to the silica gel solution and stir for 20 minutes. Add the resistance agent powder and nano-silica hollow spheres, then add the silane coupling agent, namely aminosilane coupling agent KH-550. Disperse ultrasonically at 4000W for 45 minutes, and adjust the pH to 5.0 using acetic acid or amino acid solution. The coating solution is then obtained.

[0152] S3, Coating

[0153] Glass substrate treatment: The ultra-white glass is sequentially cleaned with acetone, ethanol and deionized water in a water bath using ultrasonic cleaning; then, nitrogen is used to blow away residual liquid on the substrate surface and it is transferred to an oven for thorough drying; finally, the dried substrate is sent to a plasma cleaning device and its surface is activated under an argon atmosphere to obtain a clean pretreated glass substrate with high surface energy.

[0154] Place the cleaned photovoltaic glass substrate on the spraying station, select a single-head spraying system, and spray a volume of 32ml / ㎡.

[0155] S4, Heat Treatment

[0156] Same as in Example 1.

[0157] Comparative Examples 3-4: Preparation of Photovoltaic Glass with Different Templates

[0158] Comparative Example 3: Compared with Example 1, the hydroxypropyl methylcellulose (HPMC) in the formulation was replaced with another type of HPMC produced by Taian Ruitai Cellulose Co., Ltd., with a viscosity of 1000 mPa·s and a methoxy content of 19%.

[0159] The remaining formulation and preparation method are the same as in Example 1.

[0160] Comparative Example 4: Compared to Example 1, the hydroxypropyl methylcellulose in the formulation was replaced with polyvinylpyrrolidone (PVP) produced by BASF AG, with a viscosity of 1200 mPa·s.

[0161] The remaining formulation and preparation method are the same as in Example 1.

[0162] Test Example 1: Optical Performance Testing

[0163] The core function of photovoltaic glass coating is to enhance sunlight transmittance through the anti-reflective effect of the coating, thereby increasing the photoelectric conversion efficiency of photovoltaic modules. The surface hardness of the coating directly affects its resistance to scratches during handling, installation, and daily use. During module encapsulation, transportation, and on-site installation, the coating of photovoltaic glass inevitably comes into contact with hard objects. Insufficient surface hardness will lead to scratches, which not only affect the appearance but also cause localized light scattering and transmittance loss. Therefore, the following tests were conducted in accordance with relevant industry standards.

[0164] Photovoltaic transmittance: The optical performance was determined according to section 6.5 of JC / T 2170—2013 "Antireflective Film Glass for Solar Photovoltaic Modules". A spectrophotometer with an integrating sphere (integrating sphere diameter not less than 100 mm, distance between the sample and the integrating sphere entrance not greater than 2 mm, wavelength range 380 nm–1100 nm) was used. Photovoltaic transmittance was measured at five locations for each sample using the sampling method specified in the standard, and the arithmetic mean of the five points was taken as the measured value for that sample.

[0165] Pencil hardness: The pencil hardness is determined according to section 6.6 of JC / T 2170—2013 "Antireflective Film Glass for Solar Photovoltaic Modules". The test is conducted according to the standard method, and each sample is measured twice in parallel. If the two results are inconsistent, the test is repeated. The highest pencil hardness level that does not show obvious scratches on the film surface is taken as the pencil hardness value of the sample.

[0166] The measurement results are as follows:

[0167]

[0168] Conclusions: The photovoltaic transmittance in Examples 1-5 was ≥93.8%, which is basically equivalent to Comparative Example 1 (without boron nitride). The transmittance of Example 4 decreased due to insufficient coating thickness, and the film thickness in Example 5 decreased. Regarding hardness, the examples containing boron nitride were all superior to Comparative Example 1 (without boron nitride). In Comparative Example 2, the boron nitride in the monolayer structure was uniformly distributed; although the surface boron nitride content was increased, the hardness did not increase further.

[0169] Test Example 2: Physical Performance Testing

[0170] During actual service, especially when installed in areas prone to sandstorms such as deserts and Gobi, the surface of photovoltaic glass is continuously eroded and worn by sand and dust particles. Once the film is worn, not only is the anti-reflective effect lost and the light transmittance significantly reduced, but the microcracks generated by the wear also become channels for corrosive media to enter, accelerating the peeling of the film and the corrosion of the glass substrate.

[0171] Therefore, in order to fully compare the physical properties of the samples prepared by each technical solution, the following tests were conducted.

[0172] Test basis: ASTM G76 solid particle impact erosion test, the test was carried out using the airflow erosion tester of Shanghai Qianshi Precision Electromechanical Technology Co., Ltd., using compressed air as power to accelerate the alumina particles to the sample surface (the nozzle inner diameter was set to 4.7 mm, the spray angle to 90°, the particle speed was controlled at about 80 m / s, and the spraying time was set to 5 min).

[0173] Since the loss of film mass in photovoltaic glass is not significant, in order to fully reflect the differences between the samples, mass measurement will not be performed. Instead, photovoltaic transmittance will be measured directly, and the transmittance attenuation value of photovoltaic glass after being eroded by solid particle shavings will be compared.

[0174] Transmittance attenuation value = Transmittance before sandblasting - Transmittance after sandblasting

[0175] The measurement results are as follows:

[0176]

[0177] Conclusion: The above experimental results show that the addition of boron nitride can significantly improve the erosion resistance of the film. The boron nitride-rich zone in the bottom layer of the dual-nozzle gradient structure provides excellent impact protection, which is better than that of the single-layer uniform distribution structure (Comparative Example 2). In Example 4, the erosion resistance is somewhat reduced due to the thinner film. In Comparative Examples 3 and 4, the difference in template agent leads to lower film density and structural integrity compared to Example 1, and the erosion resistance is also significantly reduced.

[0178] Test Example 3 Cleaning Performance Test

[0179] In actual service, the surface wettability of photovoltaic glass directly affects the self-cleaning ability and anti-fouling performance of the module. A film with good hydrophobicity allows rainwater to form droplets and roll off quickly, carrying away dust and dirt adhering to the surface, reducing optical loss caused by dirt blockage, and at the same time reducing the residence time of moisture on the film surface, thus slowing down the corrosive effect of corrosive media.

[0180] Therefore, the water contact angle of the photovoltaic glass surface was determined according to GB / T 30447—2013 "Method for Measurement of Contact Angle of Nanofilms". A contact angle measuring instrument (equipped with a micro-injection system and angle analysis software) from Shanghai Xuanzhun Instruments Co., Ltd. was used, with deionized water as the test liquid and the droplet volume controlled at 2-5 μL.

[0181] The measurement results are as follows:

[0182]

[0183] Conclusion: The above experimental results show that the static water contact angles of Examples 1-5, Comparative Example 1, and Comparative Example 2 are all ≥136°, exhibiting excellent hydrophobic properties.

[0184] In high-temperature tempering, template agents often carbonize and decompose, and are not present in the finished product. However, the inventors discovered that HPMC or HPMC with different methoxyl content, as a template agent, exhibits superior hydrophobic properties compared to conventional template agents. This may be because HPMC with different methoxyl content has different thermal decomposition behaviors during the preparation process, especially during high-temperature tempering. The residual trace carbon components are embedded in the mesoporous pore wall surface of the silica film, reducing the surface energy of the film and giving the film excellent hydrophobic properties.

[0185] Test Example 4: Environmental Aging Tolerance Test

[0186] Photovoltaic glass is exposed to the outdoor environment for extended periods during actual service, inevitably suffering from environmental factors such as acid rain erosion and repeated rain rinsing. Whether the film layer can maintain its optical performance and structural integrity after environmental aging is a key indicator of its long-term service reliability. This experimental example simulates the actual working conditions of photovoltaic glass after acid rain erosion and repeated rain rinsing by a tandem aging method, first conducting acid resistance tests and then washing resistance tests, to comprehensively evaluate the environmental aging resistance performance of the film layer prepared in this invention.

[0187] Acid resistance test: The acid resistance test was conducted in accordance with the provisions of Section 6.8 of JC / T 2170—2013 "Antireflective Film Glass for Solar Photovoltaic Modules", with a hydrochloric acid concentration of 1 mol / L and an immersion time of 24 h.

[0188] Washability test: After the acid resistance test is completed, remove the sample and rinse it with deionized water. Then, conduct the washability test according to the provisions of Section 6.7 of JC / T2170—2013.

[0189] The acid resistance and scouring resistance tests were repeated five times consecutively. After the final scouring resistance test, the samples were rinsed with deionized water and anhydrous ethanol, then dried in an oven at 110℃ ± 10℃ for 0.5 h. After cooling to room temperature, the transmittance attenuation value was tested according to Experiment 2. The microstructure of the film surface was observed using a scanning electron microscope (SEM) on representative samples after the tests.

[0190] Results of aging transmittance measurement:

[0191]

[0192] Scanning electron microscopy results:

[0193] After aging tests, the film layer of the sample in Example 1 maintained a complete and continuous structure, without peeling or through cracks, with only a small number of nanoscale micropores on the surface. See the attached figures in the instruction manual for details. Figure 2 .

[0194] After aging tests, the surface of Comparative Example 1 sample showed numerous corrosion pits, and in some areas the film layer peeled off, exposing the glass substrate. See the attached diagram in the instruction manual for details. Figure 3 .

[0195] Conclusion: This invention effectively inhibits the erosion of the film layer and glass substrate by acid through the chemical inertness of boron nitride resistant agent, the bottom layer enrichment of resistant agent in monolayer gradient structure and the densification effect of hydroxypropyl methylcellulose, thus ensuring the structural integrity and optical performance stability of the film layer after aging in harsh environments.

Claims

1. A method for preparing environmentally resistant photovoltaic glass, characterized in that, It consists of the following steps: Spraying antireflective coating: Place the cleaned photovoltaic glass substrate on the spraying station, start the two-component spraying system, with the spray gun connected to coating solution A in front, spraying amount of 5-10mL / m²; coating solution B in the back, spraying amount of 20-30mL / m². Tempering heat treatment: The coated photovoltaic glass is pre-dried at 100-150℃ for 1-10 minutes, then sent to a tempering furnace for heat treatment at 680-720℃ for 3-5 minutes, and then tempered by air cooling to obtain the finished photovoltaic glass. The coating solution A and coating solution B are prepared by the following steps: S1, Preparation of tolerance agent powder Boron nitride, a resistance agent, was subjected to high-energy ball milling with zirconia balls as the ball-to-material medium. The ball-to-material weight ratio was 20-50:1, the rotation speed was 500-1000 rpm, and the ball-to-material time was 6-8 hours to obtain boron nitride nanopowder. Boron nitride nanopowder was added to an ethanol aqueous solution at 5-10 times its weight, and silane coupling agent at 0.2-2 times its weight was added. The mixture was stirred and refluxed at 50-80°C for 3 hours. After centrifugation, washing and drying, the resistant agent powder was obtained. S2, Preparation of coating solution Tetraethyl orthosilicate, anhydrous ethanol, deionized water and hydrochloric acid are mixed and stirred for 2-4 hours to obtain a transparent and homogeneous silica sol. Add the template agent hydroxypropyl methylcellulose to the silica gel solution and stir for 10-30 minutes. Add the resistance agent powder and nano-silica hollow spheres in a weight ratio of 5:1, and then add the silane coupling agent. Disperse the mixture ultrasonically for 30-60 minutes and adjust the pH value to 4-6 using acetic acid or ammonia to obtain coating solution A. Adjust the weight ratio of the resistance agent powder to the nano-silica hollow spheres to 1:5, and proceed in the same manner to obtain coating solution B.

2. The method for preparing photovoltaic glass according to claim 1, characterized in that, In the preparation of the S1 resistance agent, the boron nitride is any one of hexagonal boron nitride, cubic boron nitride, wurtzite boron nitride, and rhombohedral boron nitride; in the preparation of the S1 resistance agent and the formulation of the S2 coating solution, the silane coupling agent is any one of aminosilane coupling agent KH-550 and epoxysilane coupling agent KH-560.

3. The method for preparing photovoltaic glass according to claim 1, characterized in that, The silica sol formulation in the S2 coating solution consists of the following components by weight: 20-40 parts of tetraethyl orthosilicate 60-100 parts of anhydrous ethanol 6-15 parts deionized water 0.1-1 parts of dilute hydrochloric acid; the dilute hydrochloric acid is a 1 mol / L hydrochloric acid aqueous solution.

4. The method for preparing photovoltaic glass according to claim 1, characterized in that, The formulation of coating solution A in the S2 coating solution preparation consists of the following components by weight: 30-60 parts of silica sol Hydroxypropyl methylcellulose 0.5-3 parts 5-15 parts of the tolerant powder 1-3 parts of nano-silica hollow spheres 1-5 parts of silane coupling agent; the formulation of coating solution B in the S2 coating solution preparation, by weight, consists of the following components: 30-60 parts of silica sol Hydroxypropyl methylcellulose 0.5-3 parts 1-3 parts of tolerant powder 5-15 parts of nano-silica hollow spheres 1-5 parts of silane coupling agent.

5. The method for preparing photovoltaic glass according to any one of claims 1 and 4, characterized in that, The hydroxypropyl methylcellulose has a methoxyl content of 28%-30% and a viscosity of 400-1500 mPa·s; the nano-silica hollow spheres have a particle size of 20-100 nm.

6. An environmentally resistant photovoltaic glass, characterized in that, Prepared by the method according to any one of claims 1-4.

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