Bipv power generation window and manufacturing process thereof

Abstract

This invention belongs to the field of building materials technology, specifically relating to a BIPV (Building Integrated Photovoltaic) power-generating window and its manufacturing process. The window uses an ultra-white float glass substrate. After acid etching pretreatment, a glass enamel slurry containing two novel inorganic modifying compounds is screen-printed onto its surface. A multifunctional composite layer is then formed through stepped-heating heat treatment. The two modifying compounds are lithium zinc borate interface modifier and sodium zirconium molybdate photoelectric modifier, prepared via specific hydrothermal and sol-gel methods. Subsequently, a light-concentrating film made of stacked multilayer cholesteric liquid crystal films is bonded to the back of the functional layer, and monocrystalline silicon photovoltaic cell strips are installed at the edges. Finally, it is encapsulated with protective glass lamination. This power-generating window maintains high visible light transmittance while effectively collecting near-infrared light for power generation, exhibiting excellent thermal management performance and visual comfort. It achieves an integrated combination of building lighting and solar power generation, with a simple process suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a BIPV power generation window and its manufacturing process. Background Technology

[0002] With the rapid development of green building and low-carbon city construction, building-integrated photovoltaic (BIPV) technology has become an important way to achieve building energy self-sufficiency. Among these technologies, photovoltaic (PV) windows, as a combination of building envelope and solar power generation, not only need to meet the basic requirements of lighting, views, and aesthetics, but also need to possess high-efficiency energy conversion capabilities. However, traditional PV windows face many technical bottlenecks in practical applications: First, there is an irreconcilable contradiction between light transmittance and power generation efficiency. Ordinary PV modules often use dark or opaque designs to achieve higher power generation efficiency, severely affecting the quality of natural indoor lighting, while increasing light transmittance significantly reduces energy conversion efficiency. Second, commonly used transparent conductive materials such as indium tin oxide (ITO) suffer from high cost, brittleness, and resource scarcity, and their absorption of visible light limits further increases in light transmittance. Third, conventional PV windows have poor thermal management performance; a large amount of heat generated by solar radiation in summer is transferred indoors, increasing air conditioning energy consumption, while in winter, they cannot effectively maintain indoor temperature, resulting in low overall energy efficiency throughout the year. These factors severely restrict the large-scale application of PV windows in buildings.

[0003] At the materials level, existing functional layer material systems have significant shortcomings. While traditional glass glazes offer some decorative effects and shading, they lack intelligent management of the solar spectrum, failing to effectively separate and utilize visible and near-infrared light. Most research focuses on modifying organic polymers, but their weather resistance and anti-aging properties are insufficient to meet the decades-long service requirements of building windows. Inorganic functional materials, while possessing excellent stability, often have limited functionality, unable to simultaneously achieve multiple functions such as interface optimization, light absorption regulation, and thermal management. Especially for large-area components like building windows, material cost, manufacturing process complexity, and large-scale production capabilities are all critical factors that must be considered. Existing material systems struggle to achieve an ideal balance between performance, cost, and process feasibility, urgently requiring the development of novel inorganic functional material systems that achieve multifunctional integration through molecular structure design.

[0004] In terms of structural design and manufacturing processes, existing photovoltaic windows also suffer from numerous limitations. Traditional monolithic photovoltaic glass, while simple in structure, cannot simultaneously meet the demands of high light transmittance and high efficiency; while striped or dot-matrix cell arrangements negatively impact visual comfort and cause severe glare. Recent photovoltaic windows based on fluorescent concentrators, while improving light transmittance, suffer from drawbacks such as significant self-absorption losses and poor stability. In terms of manufacturing processes, vacuum processes such as magnetron sputtering and atomic layer deposition require large investments and consume high energy, hindering large-scale production; while conventional screen printing processes struggle to achieve precise control over the microstructure of functional layers. Furthermore, the interface compatibility between functional layers is often neglected in existing technologies, leading to increased light scattering losses, insufficient adhesion, and potential delamination over long-term use. Therefore, there is an urgent need to develop a novel photovoltaic power generation window system that achieves synergistic optimization across multiple levels, including material innovation, structural design, and manufacturing processes, to overcome existing technological bottlenecks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a BIPV power generation window and its manufacturing process.

[0006] A first aspect of the present invention provides a manufacturing process for a BIPV (Building Integrated Photovoltaic) power generation window, comprising the following steps: S1. Rinse the cut ultra-white float glass with deionized water, etch it with a mixed solution containing hydrofluoric acid and nitric acid, rinse it again with deionized water, and dry it in an oven at 98-102℃ to obtain a pretreated glass substrate; mix magnesium metaphosphate, aluminum metaphosphate, boron nitride, aluminum dihydrogen phosphate, aluminum sol, boron oxide, magnesium phosphate, potassium silicate, lithium zinc borate interface modifier, and sodium zirconate photoelectric modifier with ethyl cellulose terpineol solution and cobalt aluminum spinel, grind, and obtain a glass glaze slurry; print the glass glaze slurry onto the pretreated glass substrate, level it horizontally at room temperature, and then dry it in an oven at 98-102℃; place it in a heat treatment furnace, heat it to 145-155℃ and hold it, then heat it to 445-455℃ and hold it; heat it to 575-585℃ and hold it, and then anneal it to room temperature to obtain a functional layer glass; S2. Stack multilayer cholesteric liquid crystal films with different pitches, and form a subwavelength grating alignment layer by circular polarization holographic exposure technology to obtain a light-concentrating film; attach the light-concentrating film to the back of the functional layer glass; install monocrystalline silicon photovoltaic cell strips on the edge of the light-concentrating film glass, with the cell strips covering the edge of the glass, and then sequentially cover it with an ethylene-vinyl acetate film and a layer of protective glass, and laminate it in a vacuum laminator at 145-155℃.

[0007] In this invention, the manufacturing of the power-generating window is essentially a process in which multiple materials undergo physicochemical changes during heat treatment to form a stable composite functional system. This process begins with the partial breakage of the silicon-oxygen network on the surface of the glass substrate after mixed acid etching, forming micron-sized pits to enhance the adhesion of the glaze layer. The core of the functional layer glass preparation lies in the evolution of the glass glaze slurry in a stepped temperature field: at low temperatures, organic carriers such as ethyl cellulose and terpineol solution volatilize, and aluminum dihydrogen phosphate and aluminum sol begin to dehydrate and condense, forming an inorganic bonding network. At medium temperatures, boron oxide melts with components such as magnesium metaphosphate and aluminum metaphosphate, producing a eutectic liquid phase that penetrates into the gaps between boron nitride and potassium silicate particles. During this process, the zinc-lithium borate interface modifier softens, and its low-melting-point glass flows and tightly adheres to the surface of the glass substrate. This eliminates interfacial light scattering through the formation of chemical bonds and mechanical interlocking, while simultaneously adjusting the thermal expansion coefficient matching between the functional layer and the substrate. At the highest temperature stage, the glass-forming components in the glaze completely melt and form a continuous matrix. Cobalt aluminum spinel acts as a colorant to stabilize the color, while sodium zirconate photoelectric modifier is uniformly dispersed within the glaze layer. Its crystal structure remains stable at high temperatures and, through surface plasmon resonance and band transition mechanisms, converts absorbed near-infrared light energy into electrical energy or transfers it to edge photovoltaic cells. Finally, the annealing process releases internal stress and solidifies the microstructure of the functional layer. The lamination of the protective glass and the functional glass achieves sealing and optical coupling through the thermal crosslinking of the ethylene vinyl acetate film located between them under heat and pressure, forming a complete power generation window system. This structure not only improves the light energy utilization rate but also synergistically enhances the overall photoelectric performance of the device through the spectral selectivity of the functional layer and the waveguide effect of the focusing film.

[0008] As a preferred technical solution of the present invention, in step S1, the holding time for heating to 145-155℃ is 10-20 min; the holding time for heating to 445-455℃ is 20-30 min; and the holding time for heating to 575-585℃ is 10-20 min.

[0009] As a preferred embodiment of the present invention, in step S2, the lamination time at 145-155°C is 20-30 minutes.

[0010] As a preferred embodiment of the present invention, the preparation method of the lithium zinc borate interface modifier includes: A1. Dissolve zinc nitrate hexahydrate, lithium nitrate tetrahydrate and boric acid in deionized water to form a transparent solution. Adjust the pH to 8-9 with continuous stirring to obtain a suspension. A2. Transfer the suspension to a hydrothermal reactor and react at 175-185℃. After naturally cooling to room temperature, wash with deionized water and ethanol alternately, and dry in a vacuum drying oven at 78-82℃ to obtain precursor powder. Calcinate the precursor powder in a muffle furnace at 445-455℃, then melt it at 695-705℃ and cool it to room temperature.

[0011] In this invention, the zinc-lithium borate interface modifier forms a unique glassy structure through a combination of hydrothermal synthesis and high-temperature treatment. The reaction mechanism begins with the self-assembly of zinc and lithium ions with borate ions under alkaline conditions: zinc ions and lithium ions generated from the dissociation of zinc nitrate hexahydrate and lithium nitrate tetrahydrate in deionized water co-precipitate with borate ions generated after the hydrolysis of boric acid. In the alkaline environment provided by sodium hydroxide, a zinc-lithium borate precursor suspension is formed through hydroxyl-guided nucleation. Subsequently, under high-temperature and high-pressure hydrothermal conditions, the precursor undergoes lattice recombination and polymerization, with the boron-oxygen units transforming from a triangular configuration to a tetrahedral configuration and connecting with zinc-oxygen tetrahedra and lithium-oxygen polyhedra to construct a crystalline precursor with a three-dimensional network structure. After removing residual hydroxyl and nitrate ions through medium-temperature calcination, the precursor melts at a temperature close to 700 degrees Celsius, where the boron-oxygen network forms a homogeneous melt with lithium and zinc ions. Rapid cooling locks it into an amorphous glassy state. In this structure, lithium ions not only act as a network modifier, creating non-bridging oxygen vacancies to enhance interfacial adsorption, but also embed together with zinc into the boron-oxygen grid, giving the material low refractive index and high light transmittance, which is beneficial for achieving optical matching and interfacial strengthening in the power generation window.

[0012] As a preferred embodiment of the present invention, in step A1, the molar ratio of zinc nitrate hexahydrate, lithium nitrate tetrahydrate, and boric acid is 1:2:4.

[0013] As a preferred embodiment of the present invention, in step A2, the calcination time in the muffle furnace at 445-455°C is 2-4 hours.

[0014] As a preferred embodiment of the present invention, the preparation method of the sodium zirconate photoelectric modifier includes: B1. Dissolve zirconium oxychloride octahydrate, sodium molybdate dihydrate and citric acid in deionized water, stir in a water bath at 78-82℃, and continue heating to 115-125℃ to obtain a gel. B2. The gel is preheated at 195-205℃, then pre-calcined in a muffle furnace at 495-505℃ to obtain powder. The powder is ground and sintered in a nitrogen atmosphere at 795-805℃, and then cooled to room temperature in the furnace.

[0015] In this invention, the sodium zirconium molybdate photoelectric modifier forms a crystal structure with a specific photoelectric response through a sol-gel and controlled sintering process. Its formation mechanism is based on the hydrolytic condensation and solid-state ion diffusion of citric acid complexes: zirconium ions generated from the hydrolysis of zirconium oxychloride octahydrate form a stable complex with citric acid. This complex is connected to the molybdate ions released from sodium molybdate dihydrate in the liquid phase via oxygen bridges. During the gel formation process at 115-125℃ and subsequent pre-calcination, the organic matter begins and eventually completely decomposes. During the pre-calcination process at 195-205℃ to 495-505℃, the organic components such as citric acid within the gel are completely decomposed and removed, while zirconium, molybdenum, and sodium elements are transformed into an amorphous mixed phase of zirconium oxide, molybdenum oxide, and sodium oxide. Subsequently, during high-temperature sintering under nitrogen protection, the aforementioned amorphous oxide mixture undergoes a solid-phase reaction, with the oxides of zirconium, molybdenum, and sodium diffusing and rearranging at the atomic level, crystallizing to form a sodium zirconium molybdate composite oxide. In this crystal structure, the various valence states of molybdenum (tetravalent, pentavalent, and hexavalent) can undergo charge transfer under near-infrared light excitation, generating photogenerated carriers. Its wide bandgap and high refractive index allow the material to remain transparent in the visible light region while selectively absorbing and converting near-infrared light. The inclusion of sodium ions further regulates the charge balance within the crystal lattice, enhancing the material's conductivity and structural stability, enabling it to strengthen near-infrared absorption and promote photogenerated charge separation within the power generation window functional layer.

[0016] As a preferred embodiment of the present invention, in step B1, the molar ratio of zirconium oxychloride octahydrate, sodium molybdate dihydrate, and citric acid is 1:0.4:3.

[0017] As a preferred embodiment of the present invention, in step B2, the preheating treatment time at 195-205℃ is 2-4 hours.

[0018] In a second aspect, the present invention provides a BIPV power generation window manufactured using the aforementioned BIPV power generation window manufacturing process, comprising the following raw materials in parts by weight: 2-20 parts magnesium metaphosphate; 2-20 parts aluminum metaphosphate; 5-30 parts boron nitride; 5-40 parts aluminum dihydrogen phosphate; 5-30 parts aluminum sol; 3-30 parts boron oxide; 1-20 parts magnesium phosphate; 3-20 parts potassium silicate; 0.5-5 parts lithium zinc borate interface modifier; 1-8 parts sodium zirconium molybdate photoelectric modifier; 10-20 parts terpineol solution of ethyl cellulose; and 15-25 parts cobalt aluminum spinel.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) Breakthrough progress has been made in optical performance and energy management. By introducing a self-designed sodium zirconate photoelectric modifier, the power generation window has intelligent spectral management capabilities, which can selectively absorb photons in the near-infrared band and convert them into electrical energy, while maintaining high transmittance for visible light. This spectral separation technology effectively solves the core problem of the mutual constraint between transmittance and power generation efficiency in traditional photovoltaic windows. Combined with a light-concentrating system constructed with multilayer cholesteric liquid crystal films, the directional guidance and energy concentration of photons with specific polarization states are realized, further improving the light energy utilization rate.

[0020] (2) Exhibits superior characteristics in terms of interface performance and long-term stability. The specially developed lithium zinc borate interface modifier has a coefficient of thermal expansion that matches the glass substrate and excellent chemical compatibility, enabling it to form a strong chemical bond between the functional layer and the substrate, significantly improving interlayer adhesion. This interface optimization design effectively reduces the risk of delamination caused by thermal or mechanical stress, while also reducing interfacial light scattering loss, allowing light to pass through the functional layer more efficiently. The entire system adopts an all-inorganic material system, including specially designed glass enamel and modified compounds, ensuring that the product has extremely strong weather resistance, UV aging resistance, and temperature stability.

[0021] (3) It has significant advantages in production technology and large-scale application. The entire manufacturing process adopts full solution processing technology, combined with screen printing and low-temperature heat treatment, avoiding the high energy consumption and equipment investment of traditional vacuum processes, and greatly reducing production costs. This preparation method has good compatibility with existing architectural glass production lines, which facilitates large-scale and high-efficiency industrial production. The two key modified compounds used are both synthesized using water-based routes, the raw materials are readily available and environmentally friendly, which is in line with the development direction of green manufacturing. Through a precisely controlled stepped heating heat treatment system, the full reaction and densification of various materials in the functional layer are ensured, while maintaining the flatness and optical quality of the glass substrate. The final product integrates power generation, lighting, heat insulation and decoration functions, truly realizing the organic integration of building envelope structure and solar power generation system, providing a reliable technical solution for promoting building energy conservation and energy self-sufficiency, and has a very broad market application prospect. Detailed Implementation

[0022] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0023] The sources of some components in the examples and comparative examples are as follows: The ultra-white float glass was purchased from Jinjing Technology Co., Ltd.

[0024] The boron nitride was purchased from Momentive Advanced Materials (Shanghai) Co., Ltd.

[0025] The aluminum dihydrogen phosphate was purchased from Chongqing Chuandong Chemical (Group) Co., Ltd.

[0026] The aluminum sol was purchased from Yangzhou Zhongtianli New Material Co., Ltd.

[0027] The boron oxide was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0028] The magnesium phosphate was purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0029] The potassium silicate was purchased from Wuhan Huaxiang Technology Development Co., Ltd.

[0030] The terpineol solution of ethyl cellulose was purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0031] The cobalt-aluminum spinel was purchased from Jiangsu Zehui Magnesium-based New Materials Technology Co., Ltd.

[0032] The zinc nitrate hexahydrate was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0033] The lithium nitrate tetrahydrate was purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0034] The boric acid was purchased from Qinghai Boron Chemical Co., Ltd.

[0035] The zirconium oxychloride octahydrate was purchased from Tianjin Bodi Chemical Co., Ltd.

[0036] The sodium molybdate dihydrate was purchased from Luoyang Luanchuan Molybdenum Group Co., Ltd.

[0037] The citric acid was purchased from Shandong Yingxuan Industrial Co., Ltd. Example

[0038] This embodiment provides a manufacturing process for a BIPV power generation window; Preparation of zinc-lithium borate interface modifier: 29.7 g of zinc nitrate hexahydrate, 28.8 g of lithium nitrate tetrahydrate, and 24.8 g of boric acid were placed in a 1000 ml beaker, and 500 ml of deionized water was added. The mixture was mechanically stirred at 300 rpm for 30 min at 25 °C to form a transparent solution. The pH was slowly adjusted to 8.5 using 2 mol / L sodium hydroxide solution under continuous stirring, and a white suspension was observed to form. The suspension was transferred to a 1 L polytetrafluoroethylene-lined hydrothermal reactor and placed in a forced-air drying oven, where the temperature was increased to 180 °C at 2 °C / min and maintained for 24 h. After the reaction, the mixture was naturally cooled to 25 °C. The precipitate was washed three times alternately with 300 ml of deionized water and 200 ml of anhydrous ethanol, and then transferred to a vacuum drying oven and dried at 80 °C for 12 h to obtain the precursor powder. The precursor powder was placed in an alumina crucible and calcined in a muffle furnace at 450°C for 3 hours at a rate of 5°C / min. Then, it was melted at 700°C for 0.5 hours at a rate of 10°C / min and finally rapidly cooled to 25°C to obtain a glassy lithium zinc borate interface modifier.

[0039] Preparation of sodium zirconium molybdate photoelectric modifier: Accurately weigh 32.2 g of zirconium oxychloride octahydrate, 19.4 g of sodium molybdate dihydrate, and 57.6 g of citric acid into a 1000 ml beaker, add 500 ml of deionized water, and stir at 400 rpm for 2 h in an 80℃ constant temperature water bath until completely dissolved. Transfer the solution to a hot plate and heat to 120℃, stirring continuously until a deep blue gel forms. Place the gel in a muffle furnace and preheat to 200℃ at 3℃ / min for 3 h, then pre-calcine at 500℃ at 5℃ / min for 3 h to remove organic components. Grind the pre-calcined powder in an agate mortar for 1 h, transfer to a tube furnace, and sinter at 800℃ at 8℃ / min for 5 h under a nitrogen atmosphere. Cool to 25℃ with the furnace to obtain sodium zirconium molybdate photoelectric modifier powder.

[0040] Manufacturing of BIPV power generation windows: Take 1200mm×800mm×4mm ultra-white float glass, rinse it three times with deionized water, immerse it in a mixed solution containing 5% hydrofluoric acid and 10% nitric acid for 1 minute for etching, rinse it with deionized water until neutral, and dry it in a 100℃ oven for 30 minutes. Weigh out 125g of magnesium metaphosphate, 125g of aluminum metaphosphate, 120g of boron nitride, 180g of aluminum dihydrogen phosphate, 150g of aluminum sol, 100g of boron oxide, 50g of magnesium phosphate, 100g of potassium silicate, 30g of self-made zinc lithium borate interface modifier, and 50g of self-made sodium zirconium molybdate photoelectric modifier. Mix them with 200g of ethyl cellulose in terpineol solution and 200g of cobalt aluminum spinel. Mix them in a three-dimensional mixer at 50rpm for 1 hour, and then grind them five times with a three-roll mill until the fineness is less than 15μm. The paste was printed onto the pretreated glass surface using a 250-mesh screen printing machine. After leveling at room temperature for 10 minutes, the sample was dried in a 100℃ oven for 15 minutes. The sample was then placed in a heat treatment furnace, heated to 150℃ at a rate of 5℃ / min and held for 15 minutes, then heated to 450℃ at a rate of 3℃ / min and held for 25 minutes, and finally heated to 580℃ at a rate of 2℃ / min and held for 15 minutes, followed by controlled cooling to 25℃. Three cholesteric liquid crystal films with pitches of 350nm, 420nm, and 500nm were used to form a subwavelength grating alignment layer with a period of 460nm using circular polarization holographic exposure technology. The prepared light-concentrating film was bonded to the back of the functional layer glass with optical adhesive. A monocrystalline silicon photovoltaic cell strip with a size of 0.5mm×4mm was installed on each of the four edges. Then, an ethylene-vinyl acetate film and a 4mm thick protective glass were sequentially covered. The film was then laminated in a vacuum laminator at 150℃ and 0.8MPa pressure for 25 minutes to obtain the finished BIPV power generation window. Example

[0041] This embodiment provides a manufacturing process for a BIPV power generation window; Preparation of zinc-lithium borate interface modifier: 14.9 g of zinc nitrate hexahydrate, 14.4 g of lithium nitrate tetrahydrate, and 12.4 g of boric acid were placed in a 500 ml beaker, and 300 ml of deionized water was added. The mixture was mechanically stirred at 300 rpm for 30 min at 25 °C to form a transparent solution. The pH was slowly adjusted to 8.0 using 2 mol / L sodium hydroxide solution under continuous stirring, and a white suspension was observed to form. The suspension was transferred to a 500 ml hydrothermal reactor lined with polytetrafluoroethylene and placed in a forced-air drying oven. The temperature was increased to 180 °C at 2 °C / min, and the reaction was maintained for 20 h. After the reaction, the mixture was naturally cooled to 25 °C. The precipitate was washed three times alternately with 200 ml of deionized water and 100 ml of anhydrous ethanol, and then transferred to a vacuum drying oven and dried at 80 °C for 10 h to obtain the precursor powder. The precursor powder was placed in an alumina crucible and calcined in a muffle furnace at 450°C for 2 hours at a rate of 5°C / min. Then, it was melted at 700°C for 0.5 hours at a rate of 10°C / min and finally rapidly cooled to 25°C to obtain a glassy lithium zinc borate interface modifier.

[0042] Preparation of sodium zirconium molybdate photoelectric modifier: Accurately weigh 16.1 g of zirconium oxychloride octahydrate, 9.7 g of sodium molybdate dihydrate, and 28.8 g of citric acid into a 500 ml beaker, add 300 ml of deionized water, and stir at 400 rpm for 1.5 h in an 80 °C constant temperature water bath until completely dissolved. Transfer the solution to a hot plate and heat to 120 °C, stirring continuously until a deep blue gel forms. Place the gel in a muffle furnace and preheat to 200 °C at 3 °C / min for 2 h, then pre-calcine at 500 °C at 5 °C / min for 2 h to remove organic components. Grind the pre-calcined powder in an agate mortar for 1 h, transfer to a tube furnace, and sinter at 800 °C at 8 °C / min for 4 h under a nitrogen atmosphere. Cool to 25 °C with the furnace to obtain a light blue sodium zirconium molybdate photoelectric modifier powder.

[0043] Manufacturing of BIPV power generation windows: Take 1000mm×600mm×4mm ultra-white float glass, rinse it three times with deionized water, immerse it in a mixed solution containing 5% hydrofluoric acid and 10% nitric acid for 1 minute for etching, rinse it with deionized water until neutral, and dry it in a 100℃ oven for 30 minutes. Weigh out 75g of magnesium metaphosphate, 75g of aluminum metaphosphate, 80g of boron nitride, 120g of aluminum dihydrogen phosphate, 100g of aluminum sol, 60g of boron oxide, 30g of magnesium phosphate, 60g of potassium silicate, 15g of self-made zinc lithium borate interface modifier, and 25g of self-made sodium zirconium molybdate photoelectric modifier. Mix them with 120g of ethyl cellulose in terpineol solution and 150g of cobalt aluminum spinel. Mix them in a three-dimensional mixer at 50rpm for 1 hour, and then grind them five times with a three-roll mill until the fineness is less than 15μm. The paste was printed onto the pretreated glass surface using a 250-mesh screen printing machine. After leveling at room temperature for 10 minutes, it was dried in a 100℃ oven for 15 minutes. The sample was then placed in a heat treatment furnace, heated to 150℃ at a rate of 5℃ / min and held for 10 minutes, then heated to 450℃ at a rate of 3℃ / min and held for 20 minutes, and finally heated to 580℃ at a rate of 2℃ / min and held for 10 minutes, followed by controlled cooling to 25℃. Three cholesteric liquid crystal films with pitches of 350nm, 420nm, and 500nm were used to form a subwavelength grating alignment layer with a period of 460nm using circular polarization holographic exposure technology. The prepared light-concentrating film was bonded to the back of the functional layer glass with optical adhesive. A monocrystalline silicon photovoltaic cell strip with a size of 0.5mm×4mm was installed on each of the four edges. Then, an ethylene-vinyl acetate film and a 4mm thick protective glass were sequentially covered. The film was then laminated in a vacuum laminator at 150℃ and 0.8MPa pressure for 20 minutes to obtain the finished BIPV power generation window. Example

[0044] This embodiment provides a manufacturing process for a BIPV power generation window; Preparation of zinc-lithium borate interface modifier: 44.6 g of zinc nitrate hexahydrate, 43.2 g of lithium nitrate tetrahydrate, and 37.2 g of boric acid were placed in a 2000 ml beaker, and 600 ml of deionized water was added. The mixture was mechanically stirred at 300 rpm for 30 min at 25 °C to form a transparent solution. The pH was slowly adjusted to 9.0 using 2 mol / L sodium hydroxide solution under continuous stirring, and a white suspension was observed to form. The suspension was transferred to a 1 L polytetrafluoroethylene-lined hydrothermal reactor and placed in a forced-air drying oven, where the temperature was increased to 180 °C at 2 °C / min and maintained for 28 h. After the reaction, the mixture was naturally cooled to 25 °C. The precipitate was washed three times alternately with 400 ml of deionized water and 200 ml of anhydrous ethanol, and then transferred to a vacuum drying oven and dried at 80 °C for 14 h to obtain the precursor powder. The precursor powder was placed in an alumina crucible and calcined in a muffle furnace at 450°C for 4 hours at a rate of 5°C / min. Then, it was melted at 700°C for 1 hour at a rate of 10°C / min and finally rapidly cooled to 25°C to obtain a glassy lithium zinc borate interface modifier.

[0045] Preparation of sodium zirconium molybdate photoelectric modifier: Accurately weigh 48.3 g of zirconium oxychloride octahydrate, 29.1 g of sodium molybdate dihydrate, and 86.4 g of citric acid into a 2000 ml beaker, add 600 ml of deionized water, and stir at 400 rpm for 2.5 h in an 80℃ constant temperature water bath until completely dissolved. Transfer the solution to a hot plate and heat to 120℃, stirring continuously until a deep blue gel forms. Place the gel in a muffle furnace and preheat to 200℃ at 3℃ / min for 4 h, then pre-calcine at 500℃ at 5℃ / min for 4 h to remove organic components. Grind the pre-calcined powder in an agate mortar for 1 h, transfer to a tube furnace, and sinter at 800℃ at 8℃ / min for 6 h under a nitrogen atmosphere. Cool to 25℃ with the furnace to obtain a light blue sodium zirconium molybdate photoelectric modifier powder.

[0046] Manufacturing of BIPV power generation windows: Take 1500mm×1000mm×4mm ultra-white float glass, rinse it three times with deionized water, immerse it in a mixed solution containing 5% hydrofluoric acid and 10% nitric acid for 1 minute for etching, rinse it with deionized water until neutral, and dry it in a 100℃ oven for 30 minutes. Weigh out 200g of magnesium metaphosphate, 200g of aluminum metaphosphate, 200g of boron nitride, 300g of aluminum dihydrogen phosphate, 250g of aluminum sol, 180g of boron oxide, 100g of magnesium phosphate, 160g of potassium silicate, 50g of self-made zinc lithium borate interface modifier, and 80g of self-made sodium zirconium molybdate photoelectric modifier. Mix them with 300g of ethyl cellulose in terpineol solution and 280g of cobalt aluminum spinel. Mix them with a three-dimensional mixer at 50rpm for 1 hour, and then grind them five times with a three-roll mill until the fineness is less than 15μm. The paste was printed onto the pretreated glass surface using a 250-mesh screen printing machine. After leveling at room temperature for 10 minutes, it was dried in a 100℃ oven for 15 minutes. The sample was then placed in a heat treatment furnace, heated to 150℃ at a rate of 5℃ / min and held for 20 minutes, then heated to 450℃ at a rate of 3℃ / min and held for 30 minutes, and finally heated to 580℃ at a rate of 2℃ / min and held for 20 minutes, followed by controlled cooling to 25℃. Three cholesteric liquid crystal films with pitches of 350nm, 420nm, and 500nm were used to form a subwavelength grating alignment layer with a period of 460nm using circular polarization holographic exposure technology. The prepared light-concentrating film was bonded to the back of the functional layer glass with optical adhesive. A monocrystalline silicon photovoltaic cell strip with a size of 0.5mm×4mm was installed on each of the four edges. Then, an ethylene-vinyl acetate film and a 4mm thick protective glass were sequentially covered. The film was then laminated in a vacuum laminator at 150℃ and 0.8MPa pressure for 30 minutes to obtain the finished BIPV power generation window.

[0047] Comparative Example 1 The difference between this comparative example and Example 1 is that the manufacturing steps of the BIPV power generation window are the same as those in Example 1, but lithium zinc borate interface modifier and sodium zirconium molybdate photoelectric modifier are not added. The total mass of magnesium metaphosphate and aluminum metaphosphate is 330g (i.e., 165g of magnesium metaphosphate and 165g of aluminum metaphosphate).

[0048] Comparative Example 2 The difference between this comparative example and Example 1 is that the manufacturing steps of the BIPV power generation window are the same as those in Example 1, but only 30g of lithium zinc borate interface modifier is added, and sodium zirconium molybdate photoelectric modifier is not added. Accordingly, the total mass of magnesium metaphosphate and aluminum metaphosphate is increased to 300g (i.e., 150g of magnesium metaphosphate and 150g of aluminum metaphosphate).

[0049] Comparative Example 3 The difference between this comparative example and Example 1 is that the manufacturing steps of the BIPV power generation window are the same as those in Example 1, but 20g of conventional zinc oxide is used instead of lithium zinc borate interface modifier, and 20g of molybdenum trioxide is used instead of sodium zirconium molybdate photoelectric modifier. The total mass of magnesium metaphosphate and aluminum metaphosphate is adjusted accordingly to 290g (i.e., 145g of magnesium metaphosphate and 145g of aluminum metaphosphate).

[0050] The performance of the BIPV power generation windows obtained in Examples 1-3 and Comparative Examples 1-3 were tested in accordance with national and industry standard testing specifications.

[0051] Optical performance testing was performed using a UV-Vis-NIR spectrophotometer equipped with a 150mm integrating sphere. The measurement wavelength range was from 300nm to 2500nm, with data collected at 10nm intervals. The sample size was 100mm×100mm. The instrument was calibrated with a standard white board before testing. Visible light transmittance was calculated using a weighted average of wavelengths from 380nm to 780nm, and direct solar transmittance was calculated using a weighted average of wavelengths from 300nm to 2500nm. Haze was measured using the ratio of diffuse transmittance to total transmittance using an integrating sphere. Colorimetric parameters were measured under standard illuminant D65 and 2° observer conditions, with measurements taken at 5 different locations for each sample and the average value taken.

[0052] The photoelectric conversion efficiency of the samples was measured at 0° and 60° incident angles using a standard solar simulator. The test conditions were maintained at 1000 W / m² irradiance and 25±1℃. The incident angle was controlled by a precision rotating platform, and the IV characteristic curves at both angles were recorded using a four-probe testing system. The efficiency retention rate was calculated using the formula (efficiency at 60° incident angle / efficiency at 0° incident angle) × 100%. Each sample was measured three times, and the average value was taken. During the current-voltage characteristic curve test under the standard solar simulator, the complete IV curve from 0V to the open-circuit voltage was recorded using a four-probe testing system with a scan step of 0.01V. The maximum power point of the curve was accurately determined using a data processing system, and the voltage Vm and current Im values ​​at that point were read. Simultaneously, the measured values ​​of the open-circuit voltage Voc and short-circuit current Isc were recorded. Finally, the fill factor value of the sample was obtained using the formula FF = (Vm × Im) / (Voc × Isc) × 100%. Each sample was measured three times under different incident angle conditions, and the average value was taken.

[0053] Thermal performance testing employed the protective hot plate method. Samples were 300mm × 300mm in size. The cold plate temperature was set to 23℃, and the hot plate temperature to 43℃, ensuring a stable temperature difference of 20℃ between them. After reaching steady state, data was recorded every 10 minutes, with six consecutive measurements taken and the average value calculated. Simultaneously, an infrared thermal imager was used to record the sample surface temperature distribution under a radiation irradiance of 500W / m², while the ambient temperature was controlled at 23±2℃.

[0054] Environmental durability testing included: damp heat aging for 1000 hours at 85℃ and 85% relative humidity; UV aging with a cumulative irradiance of 100 kWh / m² at 60℃ using 0.7 W / m² UV radiation; and thermal cycling testing with 200 cycles from -40℃ to 85℃, each cycle lasting 120 minutes, with 30 minutes of high and low temperature maintenance. After the 1000-hour damp heat aging test at 85℃ and 85% relative humidity, the samples were restored for 24 hours under standard environmental conditions of 23±2℃ and 50±5% relative humidity. Subsequently, the photoelectric conversion efficiency of the samples was remeasured under the exact same standard test conditions as before aging (AM1.5G, 1000 W / m², 25℃). By comparing the efficiency values ​​before and after aging, the efficiency decay rate was calculated using the formula (efficiency before aging - efficiency after aging) / efficiency before aging × 100%.

[0055] Mechanical performance tests include: adhesion test, in which a cross-cut tester is used to form a 1mm×1mm grid on the sample surface, and after applying 600g adhesive tape, it is quickly torn off at a 60° angle, and the grid detachment is observed; impact resistance test, in which a 227g steel ball is dropped freely from a height of 1m to impact the center point of the sample. Thermal cycling tests were conducted in a programmable temperature-controlled chamber. The tests strictly adhered to a requirement of 200 cycles, with each cycle lasting 120 minutes. The specific procedure was as follows: the sample was heated from ambient temperature to 85°C at a rate of 1.5°C per minute and held at this temperature for 30 minutes. Subsequently, the sample was cooled from 85°C to -40°C at a rate not exceeding 2.1°C per minute and held at -40°C for 30 minutes. Finally, the sample was heated back to room temperature at a rate not exceeding 2.1°C per minute, completing one cycle. After the entire test, the sample underwent a visual inspection (to check for cracks), and its photoelectric conversion efficiency was retested, calculating the efficiency degradation rate relative to the pre-test level.

[0056] The performance test data above are shown in Table 1.

[0057] Table 1 Performance Test Results

[0058] The test results in Table 1 clearly show that Examples 1-3 effectively solved the long-standing technical problems in the field of BIPV power generation windows compared to Comparative Examples 1-3. Comparative Example 1, which did not use either of the two modified compounds, achieved a visible light transmittance of 66.3%, but its photoelectric conversion efficiency was 0, proving that the lack of a functional material system prevented power generation. Simultaneously, its haze was as high as 8.7%, its color difference ΔE was 5.6, its adhesion level was only 2, and it cracked during impact testing, indicating that relying solely on the basic material could not meet the requirements for optical performance and mechanical strength. Examples 1-3, by introducing the synergistic effect of lithium zinc borate interface modifier and sodium zirconium molybdate photoelectric modifier, achieved a photoelectric conversion efficiency of 3.2-3.9% while maintaining a visible light transmittance of 62.5-65.8%, successfully overcoming the contradictory relationship between transmittance and power generation efficiency. Comparative Example 2, using only the interface modifier, had a power generation efficiency of only 1.8%, and its efficiency decay rate reached 12.7% after damp heat aging, proving that the lack of sodium zirconium molybdate photoelectric modifier prevented effective photoelectric conversion and environmental stability. Comparative Example 3, using traditional zinc oxide and molybdenum trioxide as substitutes, had a power generation efficiency of only 1.1%, a 60° incident angle efficiency retention rate of only 68.3%, and exhibited color darkening after thermal cycling, confirming the shortcomings of traditional materials in terms of spectral selectivity and durability. The thermal conductivity of the example samples remained stable at 2.7-2.9 W / m²·K, lower than Comparative Example 1's 3.8 W / m²·K, indicating that the novel material system effectively improved thermal insulation performance. Regarding environmental durability, the example samples showed an efficiency decay rate of only 3.9-4.8% after 1000 hours of damp heat aging, and a transmittance change rate of no more than 1.8% after UV aging, far superior to Comparative Example 2's 12.7% and Comparative Example 3's 18.5%, demonstrating that the stable structure formed by the two modified compounds significantly improved material durability. In mechanical property testing, all example samples achieved grade 0 adhesion and passed the impact resistance test, while Comparative Examples 1 and 3 showed detachment or cracking, highlighting the crucial role of the lithium zinc borate interface modifier in enhancing interlayer bonding. These results fully demonstrate that the present invention, through the synergistic effect of two novel modified compounds, has successfully achieved the optimal balance between high light transmittance, high power generation efficiency, excellent environmental durability, and good mechanical properties in BIPV power generation windows.

Claims

1. A manufacturing process for a BIPV power generation window, characterized by the following steps: include: S1. Rinse the cut ultra-white float glass with deionized water, etch it with a mixed solution containing hydrofluoric acid and nitric acid, rinse it again with deionized water, and dry it in an oven at 98-102℃ to obtain a pretreated glass substrate; mix magnesium metaphosphate, aluminum metaphosphate, boron nitride, aluminum dihydrogen phosphate, aluminum sol, boron oxide, magnesium phosphate, potassium silicate, lithium zinc borate interface modifier, and sodium zirconate photoelectric modifier with ethyl cellulose terpineol solution and cobalt aluminum spinel, grind, and obtain a glass glaze slurry; print the glass glaze slurry onto the pretreated glass substrate, level it horizontally at room temperature, and then dry it in an oven at 98-102℃; place it in a heat treatment furnace, heat it to 145-155℃ and hold it, then heat it to 445-455℃ and hold it; heat it to 575-585℃ and hold it, and then anneal it to room temperature to obtain a functional layer glass; S2. Stack multilayer cholesteric liquid crystal films with different pitches, and form a subwavelength grating alignment layer by circular polarization holographic exposure technology to obtain a light-concentrating film; attach the light-concentrating film to the back of the functional layer glass; install monocrystalline silicon photovoltaic cell strips on the edge of the light-concentrating film glass, with the cell strips covering the edge of the glass, and then sequentially cover it with an ethylene-vinyl acetate film and a layer of protective glass, and laminate it in a vacuum laminator at 145-155℃.

2. The manufacturing process of the BIPV power generation window according to claim 1, characterized in that, In step S1, the holding time is 10-20 minutes for heating to 145-155℃; the holding time is 20-30 minutes for heating to 445-455℃; and the holding time is 10-20 minutes for heating to 575-585℃.

3. The manufacturing process of the BIPV power generation window according to claim 1, characterized in that, In step S2, the lamination time at 145-155℃ is 20-30 minutes.

4. The manufacturing process of the BIPV power generation window according to claim 1, characterized in that, The preparation method of the lithium zinc borate interface modifier includes: A1. Dissolve zinc nitrate hexahydrate, lithium nitrate tetrahydrate and boric acid in deionized water to form a transparent solution. Adjust the pH to 8-9 with continuous stirring to obtain a suspension. A2. Transfer the suspension to a hydrothermal reactor and react at 175-185℃. After naturally cooling to room temperature, wash with deionized water and ethanol alternately, and dry in a vacuum drying oven at 78-82℃ to obtain precursor powder. Calcinate the precursor powder in a muffle furnace at 445-455℃, then melt it at 695-705℃ and cool it to room temperature.

5. The manufacturing process of the BIPV power generation window according to claim 4, characterized in that, In step A1, the molar ratio of zinc nitrate hexahydrate, lithium nitrate tetrahydrate, and boric acid is 1:2:

4.

6. The manufacturing process of the BIPV power generation window according to claim 4, characterized in that, In step A2, the calcination time in the muffle furnace at 445-455℃ is 2-4 hours.

7. The manufacturing process of the BIPV power generation window according to claim 1, characterized in that, The preparation method of the sodium zirconate photoelectric modifier includes: B1. Dissolve zirconium oxychloride octahydrate, sodium molybdate dihydrate and citric acid in deionized water, stir in a water bath at 78-82℃, and continue heating to 115-125℃ to obtain a gel. B2. The gel is preheated at 195-205℃, then pre-calcined in a muffle furnace at 495-505℃ to obtain powder. The powder is ground and sintered in a nitrogen atmosphere at 795-805℃, and then cooled to room temperature in the furnace.

8. The manufacturing process of the BIPV power generation window according to claim 7, characterized in that, In step B1, the molar ratio of zirconium oxychloride octahydrate, sodium molybdate dihydrate, and citric acid is 1:0.4:

3.

9. The manufacturing process of the BIPV power generation window according to claim 7, characterized in that, In step B2, the preheating treatment at 195-205℃ takes 2-4 hours.

10. A BIPV power generation window manufactured using the manufacturing process according to any one of claims 1-9, characterized in that, The raw materials include the following parts by weight: 2-20 parts magnesium metaphosphate; 2-20 parts aluminum metaphosphate; 5-30 parts boron nitride; 5-40 parts aluminum dihydrogen phosphate; 5-30 parts aluminum sol; 3-30 parts boron oxide; and 1-20 parts magnesium phosphate. Potassium silicate 3-20 parts; lithium zinc borate interface modifier 0.5-5 parts; sodium zirconium molybdate photoelectric modifier 1-8 parts; terpineol solution of ethyl cellulose 10-20 parts; cobalt aluminum spinel 15-25 parts.

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