A glass composition, weather-resistant solar photovoltaic glass and its preparation method

Abstract

This invention discloses a glass composition, weather-resistant solar photovoltaic glass, and a method for preparing the same. The glass composition, based on oxides, comprises the following components by mass percentage: SiO2 71-75%, Al2O3 0.5-3.0%, Fe2O3 0.007-0.015%, CaO 7.0-10.0%, MgO 3.0-5.0%, Na2O 11.0-15.0%, K2O 0.01-2.0%, SO3 0.1-0.5%, TiO2 0-1.0%, Li2O 0-2.0%, Rb2O 0-2%, ZnO 0-1.0%, and ZrO2 0-1.0%. The glass of this invention exhibits significantly improved weather resistance and is suitable for long-term use as solar photovoltaic glass.

Description

Technical Field

[0001] This invention relates to the field of glass, and more particularly to a glass composition, weather-resistant solar photovoltaic glass, and a method for preparing the same. Background Technology

[0002] Vigorously developing renewable energy has become the dominant direction and unified action in the global energy revolution and the response to climate change. In recent years, photovoltaic power generation, as an important renewable energy technology, has achieved rapid development and has become a clean, low-carbon, and price-competitive energy form in many countries. In 2021, the global newly installed photovoltaic power generation capacity exceeded 175GW, an increase of 20.7% year-on-year, and the cumulative installed capacity reached 942GW, an increase of 22.8% year-on-year, indicating another strong growth in the photovoltaic market.

[0003] Currently, wind and solar power account for 9% of global power generation, and this is projected to reach 56% by 2050, indicating significant growth potential. As the encapsulation material for photovoltaic modules, photovoltaic glass requires excellent light transmittance, mechanical strength, weather resistance, and other comprehensive properties to ensure the power generation efficiency and lifespan of the photovoltaic modules. Currently, centralized photovoltaic power plants include ground-mounted photovoltaic power plants, agricultural-solar hybrid photovoltaic power plants, and fishery-solar hybrid photovoltaic power plants. Distributed photovoltaic power plants include residential photovoltaic power plants, commercial and industrial rooftop distributed photovoltaic power plants, and building-integrated photovoltaics (BIPV). Due to the different application scenarios and environmental conditions, the emphasis on glass performance varies among photovoltaic power plants.

[0004] my country's electricity demand is mainly concentrated in the east, and with industrial development, the demand continues to rise. To further address the electricity pressure in the east, provinces in the east have been vigorously developing solar-fishery complementary photovoltaic power stations and commercial and industrial rooftop distributed photovoltaic power stations in recent years. However, due to the relatively humid and acidic environment in the southeast, there is a significant need for improved weather resistance of photovoltaic modules. Traditional photovoltaic glass, due to its high sodium content, suffers from severe efflorescence and mold growth in humid environments, which seriously affects the light transmittance of the glass, thereby reducing the power generation capacity of the modules and restricting their deployment.

[0005] Due to the relatively humid and rainy external environment of photovoltaic power plants in the east, and considering the impact of extreme weather and temperature differences, solar photovoltaic glass requires higher water resistance, acid resistance, and chemical stability. Existing photovoltaic glass cannot adequately meet these requirements due to factors such as design composition and manufacturing processes; therefore, it is essential to develop a photovoltaic glass with high weather resistance.

[0006] The mainstream solar photovoltaic glass is high-sodium, medium-aluminum ultra-clear photovoltaic glass. However, the insufficient mechanical strength and fragility of ultra-clear glass, as well as the susceptibility to mold growth on the glass surface, directly affect the power generation efficiency and lifespan of photovoltaic modules. Summary of the Invention

[0007] The main objective of this invention is to provide a weather-resistant solar photovoltaic glass.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A glass composition, based on oxides, comprises the following components by mass percentage:

[0010]

[0011] The components must meet the following requirements:

[0012] (3)SiO2+Al2O3+Fe2O3+CaO+MgO+Na2O+K2O+SO3≥95wt%;

[0013] (4)TiO2+Li2O+Rb2O+ZnO+ZrO2<5%wt%;

[0014] (3) 12wt% <Li2O+Na2O+K2O+Rb2O<20wt%。

[0015] The present invention also provides a weather-resistant solar photovoltaic glass, which is prepared using the aforementioned glass composition.

[0016] Preferably, the water resistance of the weather-resistant solar photovoltaic glass is: sodium oxide precipitation of 300-450 ug / g; more preferably, 300-400 ug / g; and even more preferably, sodium oxide precipitation of 300-350 ug / g glass.

[0017] Preferably, the weather-resistant solar photovoltaic glass has the following acid resistance: light transmittance attenuation ≤ 0.20%.

[0018] Preferably, the weather-resistant solar photovoltaic glass has the following acid resistance: the light transmittance attenuation value of the glass in an acidic environment is less than 0.25%.

[0019] Preferably, the density of the weather-resistant solar photovoltaic glass is 2.500-2.510 g / cm³. 3 .

[0020] Preferably, the weather-resistant solar photovoltaic glass has a strain point of 510-520℃ and a softening point of 710-730℃.

[0021] Preferably, the weather-resistant solar photovoltaic glass exhibits good thermal cycling performance, with a light transmittance attenuation of less than 0.20%.

[0022] Preferably, the weather-resistant solar photovoltaic glass exhibits good resistance to damp heat, with a light transmittance attenuation of less than 0.40%.

[0023] This invention also provides a method for preparing a weather-resistant solar photovoltaic glass panel, which involves sequentially mixing, melting, homogenizing, float forming, and annealing the glass composition to produce a glass panel. During the float forming process, the temperature difference between the top of the arch and the bottom of the melting zone is 80-120℃ at the front end, 250-320℃ in the hot spot area, and 80-180℃ in the refining zone.

[0024] Compared with the prior art, this technical solution has the following advantages:

[0025] Technical effect 1: By comprehensively optimizing the design composition of photovoltaic glass and optimizing the ratio of various oxides in the glass, the tendency of the glass to mold is reduced, making it suitable for the hot and humid environment in the east. After testing and optimizing the composition ratio, the weather resistance of the glass is improved.

[0026] Technical effect 2: By using trace raw materials (trace elements such as titanium oxide, lithium oxide, rubidium oxide, zinc oxide, and zirconium oxide), the optimal dosage can be determined by considering the influence of different proportions of these trace elements on the weather resistance of glass.

[0027] Technical effect three: By combining trace raw materials (trace elements such as titanium oxide, lithium oxide, rubidium oxide, zinc oxide, and zirconium oxide), and considering their respective effects and mutual influences, a more ideal combination scheme can be obtained.

[0028] Technical effect four: Increasing the proportion of Al2O3 in the glass improves its mechanical strength. In ultra-clear float glass, alumina has a tetrahedral structure, which acts as a repair network, significantly improving the mechanical strength of the glass.

[0029] Technical effect 5: Through comprehensive experimental formula optimization, trace element ratio adjustment and melting process improvement, the weather resistance of the glass has been significantly improved after pilot-scale testing on the production line. Detailed Implementation

[0030] The embodiments of the present invention will be described in further detail below.

[0031] I. Glass Compositions

[0032] The glass composition according to embodiments of the present invention,

[0033] A glass composition, based on oxides, comprises the following components by mass percentage:

[0034]

[0035] The following describes the composition of the glass constituting this embodiment (the function of each component and why it is controlled within this range):

[0036] SiO2 forms an irregular continuous network structure with silicon-oxygen tetrahedral structural units, forming the glass framework. It can increase the viscosity of molten glass, reduce the tendency of glass to crystallize, and improve the chemical and thermal stability, mechanical strength, and transparency of glass. Its composition should be 71-75%, and it is advisable to control it at around 72%.

[0037] Al2O3 has a tetrahedral structure in glass, which acts as a repair network, reduces the tendency and rate of crystallization, and lowers the coefficient of thermal expansion. It is an effective glass stabilizing component. However, excessive alumina increases the viscosity of molten glass, which is not conducive to melting and clarifying the glass and the formation of streaks. Therefore, it should be controlled between 0.5% and 3.0%.

[0038] Fe2O3 is used as a colorant in glass, and different valence states result in different light absorption rates. Lower iron content in photovoltaic glass is better. Based on the iron content of ultra-white silica sand from both domestic and international sources, the iron content is controlled to be below 150 ppm.

[0039] At high temperatures, appropriate amounts of calcium oxide (CaO) can reduce the viscosity of molten glass, which is beneficial for melting and clarifying the glass. At low temperatures, it can increase the viscosity of molten glass, which is beneficial for rapid glass forming. However, excessive calcium oxide can easily increase the tendency of glass to crystallize. For example, calcium oxide exceeding 10% can make the glass brittle and increase the difficulty of forming. Therefore, it should be controlled between 7.0% and 10.0%.

[0040] MgO is a network intermediate oxide. Appropriate magnesium oxide can reduce the high-temperature viscosity of glass and reduce the tendency of glass to crystallize, thereby optimizing the overall performance of glass. However, when the proportion exceeds 5%, it increases the viscosity of the glass melt. Therefore, it should be controlled between 3.0-5.0%.

[0041] Na2O is a metal oxide that can lower the melting temperature of glass, reduce the viscosity of molten glass, and increase the high-temperature fluidity of molten glass. It is a good flux. However, excessive Na2O content can easily cause sodium ions to precipitate, leading to alkali precipitation and mold growth in the glass, and reducing the glass's weather resistance. Therefore, its content should be controlled between 11.0% and 15.0%.

[0042] K2O and Na2O produce a mixed alkali effect, which enhances the gloss of the glass and reduces the precipitation of sodium ions on the glass surface, thus improving the glass's weather resistance. Therefore, its content is controlled between 0.01-2.0%.

[0043] SO3 is produced during the glass clarification process, and its content is controlled at 0.1-0.5%.

[0044] TiO2 (titanium oxide) is a transition metal, and in silicate glasses it is generally represented by Ti. 4+ It exists and, under high temperature and high alkalinity conditions, can reduce the coefficient of glass expansion and improve the acid resistance of glass. Meanwhile, Ti... 4+It appears brownish-yellow in glass and reduces the glass's light transmittance, so the amount used should not be excessive, and its content should be controlled between 0-1.0%.

[0045] Lithium oxide (Li2O), along with sodium oxide, potassium oxide, and rubidium oxide, are all oxides of Group 1 elements and possess strong alkalinity. Taking into account the mixed alkali effect and reducing the tendency of glass to precipitate alkali, its content is controlled at 0-2%.

[0046] Rubidium oxide (Rb₂O), along with lithium oxide, sodium oxide, and potassium oxide, are all oxides of Group 1 elements and possess strong alkalinity. Taking into account the mixed alkali effect and reducing the tendency of glass to precipitate alkali, its content is controlled at 0-2%.

[0047] Zinc oxide (ZnO) can reduce the coefficient of thermal expansion of glass and improve its chemical stability, as well as extend its lifespan, thereby enhancing its chemical stability. However, zinc oxide has a high melting point and is not easily melted; its content should be controlled between 0-1.0%.

[0048] Introducing a certain amount of zirconium dioxide into the composition of ZrO2 glass can effectively improve the glass's refractive index and alkali resistance. As the amount increases, the glass viscosity gradually increases, making melting more difficult; therefore, its content should be controlled between 0-1.0%.

[0049] Photovoltaic glass is ordinary soda-lime-silicon glass, whose main components are silicon, sodium, calcium, magnesium, and aluminum. The proportion of these main components is controlled to exceed 95%, forming the main component framework of photovoltaic glass. Therefore, it is necessary to control the content of SiO2+Al2O3+Fe2O3+CaO+MgO+Na2O+K2O+SO3 to be ≥95wt%.

[0050] Titanium oxide, zinc oxide, and zirconium oxide, as trace elements, can improve the weather resistance of glass to a certain extent. However, excessive use can lead to adverse effects such as glass refractory and reduced light transmittance. Therefore, their amounts need to be controlled within a certain range. Lithium oxide and rubidium oxide mainly enhance the alkali-mixing effect of sodium oxide and potassium oxide. Their amounts are best used in small quantities; increasing the amount will actually reduce the alkali-mixing effect. Therefore, TiO2+Li2O+Rb2O+ZnO+ZrO2 < 5%wt% can effectively improve the weather resistance of glass while ensuring that other properties remain at a high level, thus maximizing the overall performance of the glass.

[0051] Li, Na, K, and Rb are all Group I oxides and can all act as fluxing agents in glass. Simultaneously, the alkali-mixing effect can improve the chemical stability of glass and significantly reduce crystallization. When their content is too low, the fluxing effect is poor, which is detrimental to glass melting; when their content is too high, it increases the risk of alkali precipitation and mold growth in the glass. Therefore, their content is controlled at 12 wt%. <Li2O+Na2O+K2O+Rb2O<20wt%。

[0052] II. Glass Plate

[0053] The glass plate of the embodiments of the present invention is prepared by the above-described glass composition using a float glass process.

[0054] III. Preparation Methods of Glass Plates

[0055] The method for preparing the glass plate according to an embodiment of the present invention involves sequentially mixing, melting, homogenizing, float molding, and annealing the aforementioned glass composition to produce a glass plate. The preparation method is as follows:

[0056] 1. Batch preparation: Based on the glass design composition and raw material test results, the dosage table of each raw material in a batch of mixture is calculated. The corresponding weight of raw materials is accurately weighed by the automatic batching system and transported to the mixer by belt. The mixer performs dry mixing and wet mixing (dry mixing for 90 seconds and wet mixing for 120 seconds) to obtain a uniformly mixed batch.

[0057] 2. Glass Melting and Homogenization: The batch material is conveyed to the kiln head hopper via belt conveyor and then evenly fed into the kiln by a feeder. Inside the kiln, fuel combustion achieves the melting and homogenization of the batch material.

[0058] The temperature difference between the top of the arch and the bottom of the melting pool is 80-120℃ at the front end, 250-320℃ in the hot spot area, and 80-180℃ in the clarification zone.

[0059] Example melting parameters are as follows:

[0060]

[0061]

[0062] Adjust the air-fuel ratio of the combustion system and test the oxygen content of each small furnace as shown in the table below:

[0063]

[0064] 3. Float glass forming and annealing: After the molten glass is melted and clarified, it enters the forming process, where the temperature is gradually reduced, and the glass changes from a liquid state to a solid state. After annealing in an annealing furnace, it forms a glass sheet.

[0065] Examples 1-6

[0066] The present invention will be described in detail below through examples and comparative examples. In the following examples and comparative examples, unless otherwise specified, all materials used are commercially available, and the methods used are conventional methods in the art, as are the detection methods for each parameter.

[0067] Table 1

[0068]

[0069] Comparative analysis:

[0070] 1. Sodium oxide is a flux for glass melting. It can lower the melting temperature of glass, reduce the viscosity of the glass melt, and increase the high-temperature fluidity of the glass melt, making it a good flux. However, too much sodium oxide content is likely to cause the precipitation of sodium ions, resulting in the glass becoming alkaline and moldy, and reducing the weather resistance of the glass. "Comparative Example 1" is used as a reference standard. "Examples 1" to "Examples 5" consider the related oxides of lithium, sodium, potassium, and rubidium in the same main group, replace part of the sodium oxide, and adjust the proportion of the related oxides of lithium, sodium, potassium, and rubidium to be 12 wt% < Li2O + Na2O + K2O + Rb2O < 20 wt% on the premise of ensuring the fluxing property, so as to obtain the best weather resistance design composition.

[0071] 2. Alumina has a tetrahedral structure in the glass, playing a role in repairing the network. It can reduce the crystallization tendency and crystallization rate of the glass, lower the expansion coefficient of the glass, and improve the mechanical strength of the glass. Through the impact resistance performance results and weather resistance test results of "Comparative Example 1" and "Example 6", when the alumina content increases, both the mechanical strength and weather resistance of the glass are improved.

[0072] Examples 7 - Examples 12

[0073] The present invention will be described in detail below through examples and comparative examples. In the following examples and comparative examples, unless otherwise specified, all materials used can be obtained through commercial purchase. Unless otherwise specified, the methods used are conventional methods in the art, as well as the detection methods for each parameter.

[0074] Table 2

[0075]

[0076]

[0077] Comparative analysis:

[0078] As trace elements, titanium oxide, zinc oxide, and zirconium oxide can improve the weather resistance of glass to a certain extent. However, too much usage will cause adverse effects such as difficult melting of the glass and reduction of light transmittance. Therefore, it needs to be controlled within a certain amount.

[0079] 1. From "Example 7" to "Example 9", by adding titanium oxide, zinc oxide, and zirconium oxide separately, the weather resistance of the glass is improved. The improvement effects of the three trace elements on weather resistance are: titanium oxide > zinc oxide ≈ zirconium oxide.

[0080] 2. From "Example 10" to "Example 12", titanium oxide, zinc oxide, and magnesium oxide are added synchronously. By changing their addition amounts and comparing the weather resistance results, it is concluded that the comprehensive weather resistance of "Example 12" is the best, that is, the glass with the proportion of titanium oxide 0.2%, zinc oxide 0.2%, and zirconium oxide 0.1% has the best weather resistance.

[0081] In summary, by increasing the dosage of titanium dioxide, zinc oxide, and zirconium oxide, the transmittance attenuation value in the glass acid resistance test was reduced. Through comparative analysis, titanium dioxide, zinc oxide, and zirconium oxide can all improve the weather resistance of glass.

[0082] IV. Testing Standards

[0083] The test standard for sodium oxide precipitation per gram of glass is as follows: Test according to standard GB / T 6582-2021. The process involves glass crushing → sieving → weighing → boiling in water → cooling → acid titration → calculating the amount of alkali precipitated based on acid consumption. The more alkali precipitated, the worse the chemical stability.

[0084] Heat resistance cycling performance test standard: Tested according to standard JC / T 2170-2013(2017) / 6.10. The sample temperature is cycled between -40℃ and 85℃ for 200 cycles. The average attenuation of the effective solar transmittance after the test should not exceed 1%.

[0085] The test standard for resistance to damp heat is as follows: The test shall be conducted according to standard JC / T 2170-2013(2017) / 6.12. The temperature is 85℃, the relative humidity is 85%, and the test duration is 1000 hours. The average attenuation of the effective solar transmittance after the test should not exceed 1%.

[0086] Acid resistance test standard: Tested according to standard JC / T 2170-2013(2017) / 6.8. The sample is placed in a 1mol / L hydrochloric acid solution at (23±2)℃ and immersed for 24h. The average attenuation of the effective transmittance of sunlight after the test should not be greater than 1%.

[0087] Impact resistance test standard: Keep the impact surface of the specimen horizontal. Place a smooth steel ball with a diameter of 50.8 mm and a mass of approximately 535 g at a height of 1200 mm above the specimen surface and allow it to fall freely. The impact point should be within 25 mm of the center of the specimen. Each specimen should only be impacted once. The specimen should not show any damage after the test.

[0088] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A glass composition, based on oxides, comprising, by weight percentage, the following components: in, The above components simultaneously satisfy: (1)SiO2+Al2O3+Fe2O3+CaO+MgO+Na2O+K2O+SO3≥95wt%; (2)TiO2+Li2O+Rb2O+ZnO+ZrO2<5%wt%; (3) 12wt% <Li2O+Na2O+K2O+Rb2O<20wt%。 2. A weather-resistant solar photovoltaic glass, characterized in that: It is prepared using the glass composition according to claim 1.

3. The weather-resistant solar photovoltaic glass as described in claim 2, characterized in that, The water resistance of the weather-resistant solar photovoltaic glass is: sodium oxide precipitation of 300-450 ug / g glass.

4. The weather-resistant solar photovoltaic glass as described in claim 3, characterized in that, Sodium oxide precipitation is 300-400 ug / g glass.

5. The weather-resistant solar photovoltaic glass as described in claim 2, characterized in that, The weather-resistant solar photovoltaic glass has the following acid resistance: the light transmittance of the glass decreases by ≤0.20% in an acidic environment.

6. The weather-resistant solar photovoltaic glass as described in claim 2, characterized in that, The density of the weather-resistant solar photovoltaic glass is 2.500–2.510 g / cm³. 3 .

7. The weather-resistant solar photovoltaic glass as described in claim 2, characterized in that, The strain point of the weather-resistant solar photovoltaic glass is 510-520℃, and the softening point is 710-730℃.

8. The weather-resistant solar photovoltaic glass as described in claim 2, characterized in that, The weather-resistant solar photovoltaic glass exhibits excellent thermal cycling performance, with a light transmittance decrease of less than 0.20%.

9. The weather-resistant solar photovoltaic glass as described in claim 2, characterized in that, The weather-resistant solar photovoltaic glass exhibits excellent resistance to damp heat, with a light transmittance attenuation of less than 0.40%.

10. A method for preparing a weather-resistant solar photovoltaic glass panel, characterized in that, The glass composition of claim 1 is sequentially mixed, melted, homogenized, float-formed, and annealed to produce a glass plate; wherein, during the float-formation process, the temperature difference between the top of the arch and the bottom of the melting section is 80-120°C at the front end, 250-320°C in the hot spot area, and 80-180°C in the clarification zone.

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