High-light-transmittance photovoltaic glass and preparation method thereof

Abstract

The invention discloses high-light-transmittance photovoltaic glass and a preparation method thereof, and belongs to the technical field of photovoltaic glass manufacturing, according to the photovoltaic glass with an asymmetric surface pattern structure, when incident light makes contact with the surface of the glass, multiple scattering and refraction occur, the specular reflection path of light is broken, the sunlight reflectivity is reduced, and the light transmittance is improved. The light transmission performance of the photovoltaic glass is remarkably improved, large-angle incident light can be captured, light loss caused by incident angle changes is reduced, and therefore the light absorption efficiency of a solar cell is improved. In the preparation process of the photovoltaic glass, flow paths and speed distribution of fluid on the two sides of the structure surface are different due to the asymmetric design of patterns, the difference promotes the fluid to form complex vortexes and secondary flows, accumulation and stagnation of the fluid in a local area can be reduced, lithium carbonate is added into the raw materials of the photovoltaic glass to serve as an auxiliary agent, and the production cost is reduced. The bubbles are promoted to rise and discharge, and the influence of the bubbles caused by eddy current on the performance of the photovoltaic glass is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic glass manufacturing, and particularly relates to a high-transmittance photovoltaic glass and a preparation method thereof. Background Art

[0002] Photovoltaic glass is an important component of solar cell modules, mainly used as the cover plate material of the cell. It has the characteristics of high light transmittance and low absorption rate, can absorb the radiant heat of solar energy in the largest range and to the greatest extent, and improve the photoelectric conversion efficiency of solar cells. At the same time, it has the properties of high strength and resistance to ultraviolet radiation. The light transmittance does not decrease during long-term use, which can effectively extend the service life of the cover plate glass. Its alkali resistance, anti-mildew ability and anti-aging performance in various environments are stronger than those of ordinary flat ultra-white glass. As the cover plate glass of solar modules, it can effectively protect solar cells from the influence of the external environment, thus being durable.

[0003] The light transmittance of photovoltaic glass directly affects the power generation efficiency of solar cells. Traditional rolled glass mostly adopts symmetric patterns (such as sunken hexagonal or quadrilateral patterns). Although it can improve the mechanical strength, there are certain defects. For example, large light loss: the symmetric structure causes multiple reflections of light, with a high reflection loss rate, and the light transmittance is generally lower than 92%; many structural defects: during the rolling process, the glass liquid flows unevenly, easily generating micro-cracks (depth > 5μm), increasing light loss and reducing the conversion efficiency of solar energy; poor adaptability to wide-angle incidence: the existing pattern designs cannot meet the absorption rates of low-angle incident light such as in the morning / evening, and scattered light when haze or PM2.5 is relatively high, resulting in a low conversion efficiency of solar energy.

[0004] Therefore, it is of great practical significance to develop a photovoltaic glass with a morphological structure that can improve the light transmittance. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-transmittance photovoltaic glass and a preparation method thereof. The prepared photovoltaic glass has a high light transmittance, and solves the problems of uneven light scattering, structural defects of ultra-thin glass, and low yield.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a high-transmittance photovoltaic glass, on the surface of which there is a sunken asymmetric pattern structure. The depth of the asymmetric pattern structure is 0.1 - 0.5 mm, and the left-right spacing and up-down spacing of the asymmetric pattern structure are both 1 - 5 mm;

[0008] The asymmetric pattern structure is a continuously undulating curve or broken line in the transverse direction of the cross-section of the photovoltaic glass;

[0009] The adjacent wave crests and wave troughs of the continuously undulating curve or broken line are asymmetrically distributed.

[0010] The pattern depth is the height from the trough of the pattern to the surface of the photovoltaic glass.

[0011] When there is an asymmetric pattern structure on the surface of the photovoltaic glass, when the incident light contacts the surface, multiple scattering and refraction will occur, breaking the specular reflection path of the light and reducing the solar light reflectivity. In optics, the relationship between the transmittance, absorbance, and reflectivity can be expressed as: transmittance + absorbance + reflectivity = 100%. Therefore, in a photovoltaic module, high transmittance, low absorbance, and low reflectivity are required, and the higher the power generation efficiency of the photovoltaic module.

[0012] Scattering causes the propagation path of light inside the photovoltaic material to extend, increasing the interaction time between light and the active layer (such as the silicon layer), enhancing the generation probability of photo-generated carriers, and thus improving the power generation efficiency of the photovoltaic module.

[0013] Due to the periodic changes in the incident angle of sunlight and the local climate in different regions, there are higher requirements for the wide-angle incident adaptability of photovoltaic modules. The complex surface structure can capture large-angle incident light (such as low-angle sunlight in the morning / evening, scattered light when there is haze or high PM2.5), reducing the light loss caused by the change in the incident angle.

[0014] Furthermore, the asymmetric pattern structure is at least one of an asymmetric wavy shape and an asymmetric zigzag shape in the transverse direction of the cross-section of the photovoltaic glass.

[0015] Furthermore, by mass percentage, the high-transmittance photovoltaic glass comprises the following raw materials:

[0016] Soda ash 10 - 15%, limestone 4 - 6%, dolomite 1.5 - 3.5%, feldspar 0.5 - 1.5%, glauber's salt 0.1 - 1%, sodium pyroantimonate 0.1 - 0.5%, aluminum hydroxide 0.1 - 0.5%, lithium carbonate 0.2 - 0.4%, and the balance is low-iron quartz sand.

[0017] In the raw materials of photovoltaic glass, quartz sand mainly acts as a network former, soda ash mainly provides sodium oxide, serves as a flux to lower the melting temperature of the glass, the main functions of mirabilite and sodium pyroantimonate are as fining agents to remove bubbles in the glass and improve the transmittance of the glass, the main function of limestone is to adjust the viscosity of the glass, the addition of dolomite can enhance the strength and durability of the glass, the alkaline components in feldspar can lower the melting temperature of the glass, and feldspar can slowly crystallize during the glass melting process to avoid the occurrence of devitrification. Devitrification will cause internal defects in the glass, affecting its transparency and service life; aluminum hydroxide has high purity and good dispersibility, can be evenly distributed in the glass, reduce light scattering, and improve the light transmittance. In addition, based on the difference in the edge structure caused by the asymmetric structure pattern in the present invention, this difference prompts the fluid to form complex vortices and secondary flows, which may enhance the stirring effect of the glass liquid, making it difficult for some microbubbles to rise and discharge. By adding an appropriate amount of lithium carbonate to the raw materials, it will decompose at high temperature to produce carbon dioxide and lithium oxide. The carbon dioxide can accelerate the bubble discharge, and lithium oxide, as an alkali metal oxide, can provide "free" oxygen ions (O 2- ), and these oxygen ions can break the silicon-oxygen bonds (Si-O-Si) in the silica network, thereby reducing the viscosity of the melt and promoting the rise and discharge of bubbles.

[0018] Further, the SiO2 content of the low-iron quartz sand is ≥99.8 wt%.

[0019] Further, the effective solar transmittance TAM1.5 of the high-transmittance photovoltaic glass is 92.31 - 92.42%.

[0020] Further, the surface compressive stress of the high-transmittance photovoltaic glass is 10 - 13 kPa.

[0021] The present invention also provides a preparation method of the high-transmittance photovoltaic glass as described above, including the following steps:

[0022] Step 1, glass liquid preparation: After mixing the glass liquid raw materials through a batching transmission device, they are sent into a kiln for high-temperature melting into glass liquid;

[0023] Step 2, calendering forming: The glass liquid is calendered through a calender roll engraved with an asymmetric pattern structure with protrusions to obtain a glass plate;

[0024] Step 3, annealing process: The calendered glass plate needs to be heat-treated to eliminate the thermal stress of the glass. The glass plate is gradually cooled through five temperature zones of an annealing kiln, and finally reaches a state with no surface defects, uniform thickness, suitable for cutting and further processing;

[0025] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass, thereby enhancing the strength and impact resistance of the glass. It is heated at 700 - 750°C and then air quenched, and after cutting, high-transmittance photovoltaic glass is obtained.

[0026] During the above preparation process, due to the existence of an asymmetric pattern structure on the surface of the rolled glass plate, this pattern structure will cause different forming structures in different regions, resulting in uneven cooling air flow during the annealing process, and problems such as local temperature gradient and uneven stress distribution may occur. By controlling the temperature and cooling rate in different temperature zones, step-by-step cooling is achieved to avoid problems of excessive stress or uneven distribution.

[0027] Further, the temperature of the high-temperature melting is 1500 - 1600°C.

[0028] Further, the rolling temperature of the roll forming is 1000 - 1100°C.

[0029] Further, the upper and lower roll speed ratio of the roll forming is 1:1.05 - 1.10.

[0030] Further, in step 2, the forming thickness of the glass plate is 1.00 - 2.00 mm.

[0031] Further, the temperature settings of the annealing furnace are as follows:

[0032] The temperature in the first stage of the annealing furnace is 542 ± 5°C, the temperature in the second stage is 448 ± 5°C, the temperature in the third stage is 328 ± 5°C, the temperature in the fourth stage is 168 ± 5°C, and the temperature in the fifth stage is 80 ± 5°C.

[0033] Advantages of the present invention:

[0034] (1) For the photovoltaic glass with an asymmetric surface pattern structure prepared by the present invention, when incident light contacts the glass surface, multiple scattering and refraction occur, breaking the specular reflection path of the light, reducing the solar light reflectance, and significantly improving the light transmittance performance of the photovoltaic glass, thereby enhancing the light absorption efficiency of the solar cell. Under the same process mode, it is measured that the light transmittance of the asymmetric pattern glass of the present invention is increased by about 0.1% - 0.15% compared with that of the symmetric pattern glass.

[0035] (2) During the preparation process of the photovoltaic glass of the present invention, due to the asymmetric design of the pattern, the flow path and velocity distribution of the fluid on both sides of the structure surface are different. This difference prompts the fluid to form complex vortices and secondary flows, and these flow patterns can effectively disperse the energy of the fluid, reduce the accumulation and stagnation of the fluid in local areas, and thus make the tissue structure of the rolled glass plate more uniform.

[0036] (3) The present invention can capture large-angle incident light (such as low-angle sunlight in the morning / evening, scattered light when haze or PM2.5 is relatively high) by constructing a complex asymmetric surface structure, reducing light loss caused by changes in the incident angle.

[0037] (4) Lithium carbonate is added as an auxiliary agent to the raw materials of the photovoltaic glass in the present invention. On the one hand, it can generate carbon dioxide to accelerate the bubble discharge, avoiding the bubble aggregation caused by the melt vortex under the asymmetric pattern structure. On the other hand, the generated lithium oxide can reduce the melt viscosity, further promoting the rise and discharge of bubbles. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described below in conjunction with the drawings.

[0039] Figure 1 is a schematic diagram of the calendering forming of the photovoltaic glass in Embodiment 1 of the present invention;

[0040] In the figure: 1, the calender roll body; 2, the surface pattern structure of the calender roll; 3, the calendered photovoltaic glass plate; 4, the asymmetric wavy pattern structure on the glass surface;

[0041] Figure 2 is a schematic diagram of the propagation path of the light path in the photovoltaic glass with an asymmetric pattern structure;

[0042] In the figure: 5, the propagation path of the light path under the wavy pattern structure; 6, the internal cross-section of the glass; 7, the propagation path of the light path under the asymmetric zigzag pattern structure;

[0043] Figure 3 is a comparison chart of the light transmittance of Embodiment 1 of the present invention and Comparative Example 1;

[0044] Figure 4 is a schematic plan view of the pattern structures of Comparative Example 1 and Comparative Example 2 of the present invention;

[0045] In the figure: the left figure is the quadrilateral pattern structure of Comparative Example 1, and the right figure is the hexagonal pattern structure of Comparative Example 2;

[0046] Figure 5 is a schematic diagram of the propagation path of the light path in the photovoltaic glass with a symmetric pattern structure;

[0047] In the figure: 8, the propagation path of the light path under the symmetric pattern structure. DETAILED DESCRIPTION OF THE INVENTION

[0048] Next, in combination with the embodiments of the present invention and the accompanying drawings, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0049] Embodiment 1

[0050] This embodiment provides a high light transmittance photovoltaic glass. The surface of the photovoltaic glass is provided with an asymmetric pattern structure. The depth of the asymmetric pattern structure is 0.1 - 0.5 mm, the spacing is 3 mm, and the transverse direction of the asymmetric pattern structure in the cross-section of the photovoltaic glass is an asymmetric wavy shape.

[0051] The preparation method of the above photovoltaic glass is as follows:

[0052] Step 1: Preparation of glass liquid: Prepare the raw materials for glass liquid. After mixing through the batching transmission equipment, set the temperature of the furnace to 1550 °C, and send the mixed materials into the furnace for high-temperature melting to form glass liquid. The raw material ratio is as follows:

[0053] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.2%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0054] Step 2: Calendering and forming: As Figure 1 shown, the glass liquid is subjected to calendering and forming treatment. Use a calendering roll 1 with a convex asymmetric wavy pattern structure on the surface (the asymmetric wavy pattern is distributed along the calendering direction of the calendering roll, the height of the convex point of the pattern from the roll surface is 0.1 - 0.5 mm, and the upper and lower and left and right spacings of the pattern are both 3 mm). The high-temperature glass liquid is calendered and formed. The calendering temperature is 1070 °C, and the upper and lower roll speed ratio of the calendering roll is 1:1.05, obtaining a photovoltaic glass plate 3 with an asymmetric wavy pattern structure 4, and the thickness is 2.0 mm;

[0055] Step 3: Annealing process: Set the temperatures of the five temperature zones of the annealing furnace. The calendered glass plate enters the annealing furnace for step-by-step cooling. The middle temperature zone of the annealing furnace is divided into five stages. The temperature of the first stage is set to 542 °C, the temperature of the second stage is set to 448 °C, the temperature of the third stage is set to 328 °C, the temperature of the fourth stage is set to 168 °C, and the temperature of the fifth stage is set to 80 °C;

[0056] Step 4, Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched. After cutting, high-transmittance photovoltaic glass is obtained. The propagation path of the light in the photovoltaic glass with an asymmetric wavy pattern structure is as Figure 2 shown in Figure 5. When light irradiates on the asymmetric wavy structure on the glass surface, the light will refract and reflect. The refracted light can pass through the glass interior and be absorbed and utilized by the solar cell, while the reflected light will be emitted to the adjacent structure surface and undergo secondary refraction. Then, the refracted light passes through the glass interior and is absorbed and utilized by the solar cell, increasing the transmittance.

[0057] Example 2

[0058] The difference from Example 1 is only that the pattern structure is an asymmetric zigzag.

[0059] This example provides a high-transmittance photovoltaic glass. The surface of the photovoltaic glass is provided with an asymmetric pattern structure. The depth of the asymmetric pattern structure is 0.1 - 0.5 mm, the spacing is 3 mm, and the asymmetric pattern structure is asymmetric zigzag in the transverse direction of the cross-section of the photovoltaic glass.

[0060] The preparation method of the above photovoltaic glass is as follows:

[0061] Step 1, Glass melt preparation: Prepare the glass melt raw materials. After mixing through the batching transmission equipment, set the furnace temperature to 1550 °C, and feed the mixed materials into the furnace for high-temperature melting to form glass melt. The raw material ratio is as follows:

[0062] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.2%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0063] Step 2, Calendering: As Figure 1 shown, perform calendering on the glass melt. Use a calendering roll with an asymmetric zigzag pattern with protrusions on the surface (the asymmetric zigzag pattern is distributed along the calendering direction of the calendering roll. The height of the convex points of the pattern from the roll surface is 0.1 - 0.5 mm, and the upper and lower and left and right spacings of the pattern are both 3 mm). Perform calendering on the high-temperature glass melt at a calendering temperature of 1070 °C and a calendering roll upper and lower roll speed ratio of 1:1.05 to obtain a photovoltaic glass plate with an asymmetric zigzag pattern structure, with a thickness of 2.0 mm;

[0064] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing furnace. The rolled glass plate enters the annealing furnace for step-by-step cooling. The medium temperature zone in the annealing furnace is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0065] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched. After cutting, high-transmittance photovoltaic glass is obtained. The propagation path of light in the photovoltaic glass with an asymmetric zigzag pattern structure is as Figure 2 shown in Figure 7.

[0066] Example 3

[0067] The difference from Example 1 is only that the pattern structure is a transverse spaced distribution of asymmetric zigzag and asymmetric wavy shapes in the glass cross-section.

[0068] This example provides a high-transmittance photovoltaic glass. The surface of the photovoltaic glass is provided with an asymmetric pattern structure. The depth of the pattern structure is 0.1 - 0.5 mm, the spacing is 3 mm, and the pattern structure is a transverse spaced distribution of asymmetric zigzag and asymmetric wavy shapes in the glass cross-section.

[0069] The preparation method of the above photovoltaic glass is as follows:

[0070] Step 1. Glass melt preparation: Prepare the raw materials for the glass melt. After mixing through the batching transmission equipment, set the furnace temperature at 1550 °C, and feed the mixed materials into the furnace for high-temperature melting to form the glass melt. The raw material ratio is as follows:

[0071] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.2%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0072] Step 2. Rolling forming: As Figure 1 shown, perform rolling forming treatment on the glass melt. Use a rolling roller with an asymmetric trapezoidal pattern structure and an asymmetric wavy pattern structure with protrusions on the surface (the asymmetric zigzag pattern and the asymmetric wavy pattern are spaced along the rolling direction of the rolling roller. The height of the convex points of the pattern from the roller surface is 0.1 - 0.5 mm, and the upper and lower and left and right spacings of the pattern are both 3 mm). Perform rolling forming on the high-temperature glass melt. The rolling temperature is 1070 °C, and the upper and lower roller speed ratio of the rolling roller is 1:1.05 to obtain a photovoltaic glass plate with an asymmetric zigzag and asymmetric wavy pattern structure, with a thickness of 2.0 mm;

[0073] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing furnace. The rolled glass plate enters the annealing furnace for step-by-step cooling. The middle temperature zone of the annealing furnace is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0074] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched, and high-transmittance photovoltaic glass is obtained after cutting.

[0075] Example 4

[0076] The difference from Example 1 is only that the proportion of lithium carbonate in the glass melt raw material is adjusted to 0.3%.

[0077] This example provides a high-transmittance photovoltaic glass. The surface of the photovoltaic glass is provided with an asymmetric pattern structure. The depth of the asymmetric pattern structure is 0.1 - 0.5 mm, the spacing is 3 mm, and the asymmetric pattern structure is an asymmetric wavy shape in the transverse direction of the cross-section of the photovoltaic glass.

[0078] The preparation method of the above photovoltaic glass is as follows:

[0079] Step 1. Glass melt preparation: Prepare the glass melt raw materials. After mixing through the batching transmission equipment, set the furnace temperature at 1550 °C, and send the mixed materials into the furnace for high-temperature melting to form glass melt. The raw material ratio is as follows:

[0080] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, sodium sulfate is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.3%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0081] Step 2. Rolling forming: As Figure 1 shown, perform rolling forming treatment on the glass melt. Use a rolling roll 1 with a convex asymmetric wavy pattern structure on the surface (the asymmetric wavy pattern is distributed along the rolling direction of the rolling roll, the height of the convex point of the pattern from the roll surface is 0.1 - 0.5 mm, and the spacing between the upper and lower and left and right of the pattern is 3 mm). The high-temperature glass melt is rolled formed at a rolling temperature of 1070 °C and a roll speed ratio of the upper and lower rolls of 1:1.05 to obtain a photovoltaic glass plate with an asymmetric wavy pattern structure, with a thickness of 2.0 mm;

[0082] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing kiln. The rolled glass plate enters the annealing kiln for step-by-step cooling. The middle temperature zone of the annealing kiln is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0083] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched, and high-transmittance photovoltaic glass is obtained after cutting.

[0084] Example 5

[0085] The difference from Example 1 is only that the proportion of lithium carbonate in the glass melt raw materials is adjusted to 0.4%.

[0086] This example provides a high-transmittance photovoltaic glass. The surface of the photovoltaic glass is provided with an asymmetric pattern structure. The depth of the asymmetric pattern structure is 0.1 - 0.5 mm, the spacing is 3 mm, and the transverse direction of the asymmetric pattern structure in the cross-section of the photovoltaic glass is an asymmetric wavy shape.

[0087] The preparation method of the above photovoltaic glass is as follows:

[0088] Step 1. Glass melt preparation: Prepare the glass melt raw materials. After mixing through the batching transmission equipment, set the furnace temperature at 1550 °C, and feed the mixed materials into the furnace for high-temperature melting to form glass melt. The raw material ratio is as follows:

[0089] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.4%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0090] Step 2. Rolling forming: As Figure 1 shown, perform rolling forming treatment on the glass melt. Use a rolling roll 1 with a convex asymmetric wavy pattern structure on the surface (the asymmetric wavy pattern is distributed along the rolling direction of the rolling roll, the height of the convex point of the pattern from the roll surface is 0.1 - 0.5 mm, and the spacing of the pattern in the up-down and left-right directions is both 3 mm). The high-temperature glass melt is rolled formed. The rolling temperature is 1070 °C, and the speed ratio of the upper and lower rolls of the rolling roll is 1:1.05, obtaining a photovoltaic glass plate with an asymmetric wavy pattern structure, with a thickness of 2.0 mm;

[0091] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing furnace. The rolled glass plate enters the annealing furnace for step-by-step cooling. The middle temperature zone of the annealing furnace is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0092] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched, and high-transmittance photovoltaic glass is obtained after cutting.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that the surface pattern structure of the photovoltaic glass in this comparative example is a quadrangular prism.

[0095] This comparative example provides a photovoltaic glass. The surface of the photovoltaic glass is provided with a symmetrical pattern structure. The depth of the pattern structure is 0.3 mm, the spacing is 3 mm, the pattern structure is a quadrangular prism on the surface of the photovoltaic glass, and the cross section is a trapezoid.

[0096] The preparation method of the above photovoltaic glass is as follows:

[0097] Step 1. Glass melt preparation: Prepare the glass melt raw materials. After mixing through the batching transmission equipment, set the furnace temperature at 1550 °C, and feed the mixed materials into the furnace for high-temperature melting to form glass melt. The raw material ratio is as follows:

[0098] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.2%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0099] Step 2. Rolling forming: As Figure 1 shown, perform rolling forming treatment on the glass melt. Use a rolling roll with a raised quadrangular prism pattern structure on the surface (the height of the convex points of the pattern from the roll surface is 0.3 mm, and the spacing between the upper and lower and left and right of the pattern is 3 mm). The high-temperature glass melt is rolled formed. The rolling temperature is 1070 °C, and the upper and lower roll speed ratio of the rolling roll is 1:1.05, obtaining a photovoltaic glass plate with a quadrangular prism pattern structure, with a thickness of 2.0 mm;

[0100] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing furnace. The rolled glass plate enters the annealing furnace for step-by-step cooling. The middle temperature zone of the annealing furnace is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0101] Step 4. Tempering process: The annealed glass sheet is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched. After cutting, high-transmittance photovoltaic glass is obtained. The schematic diagram of the planar structure of the surface pattern of the glass is shown as Figure 4 shown in the left figure in the middle. The pattern in the cross-section structure of the photovoltaic glass is shown as Figure 5 shown in the middle, Figure 5 which is the propagation path of the light in the photovoltaic glass with a symmetric pattern structure. When light irradiates on the symmetric pattern structure on the glass surface, the light will undergo refraction and specular reflection. The refracted light energy can pass through the glass interior and be absorbed and utilized by the solar cells, while the reflected light will be emitted into the air.

[0102] Comparative Example 2

[0103] The difference from Example 1 is that the surface pattern structure of the photovoltaic glass in this comparative example is hexagonal.

[0104] This comparative example provides a photovoltaic glass with a symmetric pattern structure on the surface. The depth of the pattern structure is 0.3 mm, the spacing is 3 mm, the pattern structure is hexagonal on the surface of the photovoltaic glass, and the cross-section is trapezoidal.

[0105] The preparation method of the above photovoltaic glass is as follows:

[0106] Step 1. Glass melt preparation: Prepare the raw materials for the glass melt. After mixing through the batching transmission equipment, set the temperature of the furnace to 1550 °C, and feed the mixed materials into the furnace for high-temperature melting to form the glass melt. The raw material ratio is as follows:

[0107] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, lithium carbonate is 0.2%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0108] Step 2. Calendering: As Figure 1 shown, the glass melt is calendered. A calender roll with a hexagonal pattern structure with protrusions on the surface is used (the height of the convex points of the pattern from the roll surface is 0.3 mm, and the spacing between the upper and lower and left and right of the pattern is 3 mm). The high-temperature glass melt is calendered at a calendering temperature of 1070 °C and a calender roll upper and lower roll speed ratio of 1:1.05 to obtain a photovoltaic glass sheet with a hexagonal pattern structure, with a thickness of 2.0 mm;

[0109] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing furnace. The rolled glass plate enters the annealing furnace for step-by-step cooling. The medium temperature zone in the annealing furnace is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0110] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched. After cutting, high-transmittance photovoltaic glass is obtained. The schematic diagram of the planar structure of the surface pattern of the glass is as Figure 4 shown in the right figure in the middle, and the pattern in the cross-section structure of the photovoltaic glass is as Figure 5 shown in the middle.

[0111] Comparative Example 3

[0112] The difference from Example 1 is that lithium carbonate is not added to the glass melt raw material in this comparative example.

[0113] This comparative example provides a high-transmittance photovoltaic glass with an asymmetric pattern structure on the surface of the photovoltaic glass. The depth of the asymmetric pattern structure is 0.1 - 0.5 mm, the spacing is 3 mm, and the horizontal direction of the asymmetric pattern structure in the cross-section of the photovoltaic glass is an asymmetric wavy shape.

[0114] The preparation method of the above photovoltaic glass is as follows:

[0115] Step 1. Glass melt preparation: Prepare the glass melt raw materials. After mixing through the batching transmission equipment, set the furnace temperature at 1550 °C, and feed the mixed materials into the furnace for high-temperature melting to form glass melt. The raw material ratio is as follows:

[0116] By mass percentage, soda ash is 13%, limestone is 5%, dolomite is 2.5%, feldspar is 1.0%, glauber's salt is 0.5%, sodium pyroantimonate is 0.3%, aluminum hydroxide is 0.3%, and the balance is low-iron quartz sand (SiO2 content ≥ 99.8 wt%);

[0117] Step 2. Rolling forming: As Figure 1 shown, perform rolling forming treatment on the glass melt. Use a rolling roll 1 with a convex asymmetric wavy pattern structure on the surface (the asymmetric wavy pattern is distributed along the rolling direction of the rolling roll, the height of the convex point of the pattern from the roll surface is 0.1 - 0.5 mm, and the upper and lower and left and right spacings of the pattern are both 3 mm). Perform rolling forming on the high-temperature glass melt at a rolling temperature of 1070 °C and a roll speed ratio of the upper and lower rolls of 1:1.05 to obtain a photovoltaic glass plate with an asymmetric wavy pattern structure, with a thickness of 2.0 mm;

[0118] Step 3. Annealing process: Set the temperatures of the five temperature zones in the annealing kiln. The rolled glass plate enters the annealing kiln for step-by-step cooling. The middle temperature zone of the annealing kiln is divided into five stages. The temperature of the first stage is set at 542 °C, the temperature of the second stage is set at 448 °C, the temperature of the third stage is set at 328 °C, the temperature of the fourth stage is set at 168 °C, and the temperature of the fifth stage is set at 80 °C;

[0119] Step 4. Tempering process: The annealed glass plate is tempered to increase the internal stress of the glass. It is heated to 750 °C and then air quenched, and high-transmittance photovoltaic glass is obtained after cutting.

[0120] The performance of the photovoltaic glass prepared in Examples 1-5 and Comparative Examples 1-3 was tested, and the results are shown in Table 1.

[0121] Use the Aoptek Filmeasure 2100 air-floating tabletop photovoltaic glass transmittance measurement system to detect the effective solar transmittance TAM1.5 of the photovoltaic glass prepared in Examples 1-5 and Comparative Examples 1-3.

[0122] Refer to the standard "GB / T 30983-2014 Test Method for Optical Properties of Glass for Photovoltaic Applications" to detect the light transmittance of the photovoltaic glass in Example 1 and Comparative Example 1. The test wavelength is 380-1100 nm, as Figure 3 shown.

[0123] Table 1

[0124]

[0125] As can be seen from Table 1, the photovoltaic glass with different asymmetric pattern structures in Examples 1-3 has a higher light transmittance than the photovoltaic glass with symmetric pattern structures in Comparative Examples 1 and 2. Among the examples, under the lithium carbonate addition amount condition of Example 4, the photovoltaic glass has the maximum light transmittance and the lowest haze value.

[0126] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0127] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high light transmittance photovoltaic glass, characterized in that, The surface of the photovoltaic glass is provided with a sunken asymmetric pattern structure, the depth of the asymmetric pattern structure is 0.1 - 0.5 mm, and the left - right spacing and up - down spacing of the asymmetric pattern structure are both 1 - 5 mm; The asymmetric pattern structure is a continuously undulating curve or broken line in the transverse direction of the cross - section of the photovoltaic glass; The adjacent wave peaks and wave valleys of the continuously undulating curve or broken line are asymmetrically distributed.

2. The high light transmittance photovoltaic glass according to claim 1, wherein The asymmetric pattern structure is at least one of an asymmetric wavy shape and an asymmetric zigzag shape in the transverse direction of the cross - section of the photovoltaic glass.

3. A high light transmittance photovoltaic glass according to claim 1, characterized in that, By mass percentage, the high - light - transmittance photovoltaic glass comprises the following raw materials: Soda ash 10 - 15%, limestone 4 - 6%, dolomite 1.5 - 3.5%, feldspar 0.5 - 1.5%, glauber's salt 0.1 - 1%, sodium pyroantimonate 0.1 - 0.5%, aluminum hydroxide 0.1 - 0.5%, lithium carbonate 0.2 - 0.4%, and the balance is low - iron quartz sand.

4. A high light transmittance photovoltaic glass according to claim 1, characterized in that, The effective solar transmittance TAM1.5 of the high - light - transmittance photovoltaic glass is 92.31 - 92.42%.

5. A highly light-transmissive photovoltaic glass according to claim 1, characterized in that, The surface compressive stress of the high - light - transmittance photovoltaic glass is 10 - 13 kPa.

6. A method for preparing a high light transmittance photovoltaic glass according to any one of claims 1-5, characterized in that, Including the following steps: Step 1, glass melt preparation: After mixing the glass melt raw materials through a batching transmission device, they are sent into a kiln for high - temperature melting into glass melt; Step 2, calendering forming: The glass melt is calendered through a calender roll engraved with a convex asymmetric pattern structure to obtain a glass plate; Step 3, annealing process: The calendered glass plate needs to be heat - treated to eliminate the thermal stress of the glass, and the glass plate is gradually cooled through an annealing kiln; Step 4, toughening process: The annealed glass plate is toughened to increase the internal stress of the glass, heated at 700 - 750 °C and then air - quenched, and cut to obtain the high - light - transmittance photovoltaic glass.

7. The preparation method of a high light transmittance photovoltaic glass according to claim 6, wherein, The temperature of the high - temperature melting is 1500 - 1600 °C.

8. The preparation method of a high light transmittance photovoltaic glass according to claim 6, characterized in that, The calendering temperature of the calendering forming is 1000 - 1100 °C; The upper - lower roll speed ratio of the calender roll for the calendering forming is 1:1.05 - 1.

10.

9. The preparation method of a high light transmittance photovoltaic glass according to claim 6, characterized in that, In step 2, the forming thickness of the glass plate is 1.00 - 2.00 mm.

10. The preparation method of a high light transmittance photovoltaic glass according to claim 6, characterized in that, The temperature of the annealing kiln is set as follows: The temperature in the first stage of the annealing kiln is 542 ± 5 °C, the temperature in the second stage is 448 ± 5 °C, the temperature in the third stage is 328 ± 5 °C, the temperature in the fourth stage is 168 ± 5 °C, and the temperature in the fifth stage is 80 ± 5 °C.

Images