Ultra-white float photovoltaic glass and manufacturing method therefor

Abstract

The present application relates to the field of photovoltaic glass, and discloses ultra-white float photovoltaic glass and a manufacturing method therefor. The ultra-white float photovoltaic glass of the present application comprises the following components: 71%-73% of SiO2, 0.5%-1.5% of Al2O3, 0.008%-0.012% of Fe2O3, 7.5%-9.5% of CaO, 3.5%-5.0% of MgO, 12.5%-14.0% of Na2O, 0.2%-1.0% of K2O, and 0.2%-0.4% of SO3. According to the present application, by adjusting the composition of the glass and in combination with adjustments of a melting process and a tin bath forming process, the content proportion of ferrous irons in the ultra-white float photovoltaic glass is reduced, the content proportion of ferric irons is increased, and the tin count in the glass is reduced to achieve the purpose of improving the transmittance, flatness and weather resistance of the ultra-white float photovoltaic glass, thereby satisfying the quality requirements of the photovoltaic glass, and the photovoltaic glass can be applied to a photovoltaic module.

Description

Ultra-white float photovoltaic glass and preparation method thereof

[0001] Related applications

[0002] This application claims priority to Chinese patent application No. 202310868559.5 filed on July 14, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of photovoltaic glass, and in particular to an ultra-white float photovoltaic glass and a preparation method thereof. Background Art

[0004] Photovoltaic glass is an essential material for photovoltaic modules. It is widely used as the cover glass for crystalline silicon single-glass modules, the cover and back panels for double-glass modules, and the substrate glass for thin-film modules. The primary function of photovoltaic glass in modules is to transmit light and protect the cells. Therefore, the basic requirements for photovoltaic glass are high light transmittance, high strength, and high durability.

[0005] The front glass of crystalline silicon photovoltaic modules has always been ultra-clear patterned glass. However, with the continuous development and advancement of photovoltaic cell technology, ultra-clear patterned glass alone can no longer meet the requirements of all photovoltaic modules. For example, with the development of monocrystalline PERC bifacial modules and the rise of new technologies with higher bifaciality, such as TOPCon cells and heterojunction HJT cells, the proportion of double-glass panels will continue to increase, and the back glass will gradually be made of ordinary float glass and ultra-clear float glass. In addition, with the development of second-generation thin-film technologies such as cadmium telluride and copper indium gallium selenide, as well as the development of third-generation perovskite thin-film cells, the unique characteristics of thin-film cells require the use of ultra-clear float glass.

[0006] However, existing conventional float glass production lines typically operate on a single kiln and are primarily used to produce large-size architectural glass with a thickness of 5-12mm, resulting in relatively low transmittance. Conventional photovoltaic glass, on the other hand, has a thickness between 3.2mm and 2.0mm and a transmittance requirement of at least 91.6%. Therefore, even ultra-clear float glass produced on conventional float glass production lines cannot meet the quality requirements of photovoltaic glass, necessitating adjustments to the glass material formula and production methods.

[0007] Application Contents

[0008] The main purpose of this application is to provide an ultra-white float photovoltaic glass and a preparation method thereof, aiming to solve the technical problems that the glass obtained by the existing float production process has low light transmittance, unsatisfactory thickness, and is difficult to meet the quality requirements of photovoltaic glass.

[0009] To achieve the above-mentioned object, the present application provides an ultra-clear float photovoltaic glass. Calculated by mass percentage, the ultra-clear float photovoltaic glass comprises the following components:

[0010] SiO2: 71%-73%,

[0011] Al2O3: 0.5%-1.5%,

[0012] Fe2O3: 0.008%-0.012%,

[0013] CaO: 7.5%-9.5%,

[0014] MgO: 3.5%-5.0%,

[0015] Na2O: 12.5%-14.0%,

[0016] K2O: 0.2%-1.0%,

[0017] SO3: 0.2%-0.4%,

[0018] Among them, ∑Na2O+K2O is 12.5%-15%; ∑CaO+MgO is 11%-14%; ∑SiO2+Al2O3 is 71.5%-74%.

[0019] In one embodiment of the present application, the ultra-clear float photovoltaic glass comprises the following components, calculated by mass percentage:

[0020] SiO2: 71.5%-72.5%,

[0021] Al2O3: 0.8%-1.2%,

[0022] Fe2O3: 0.008%-0.010%,

[0023] CaO: 8.0%-9.0%,

[0024] MgO: 4.0%-5.0%,

[0025] Na2O: 13.0%-14.0%,

[0026] K2O: 0.5%-1.0%,

[0027] SO3: 0.2%-0.3%,

[0028] Among them, ∑Na2O+K2O is 13.5%-14%; ∑CaO+MgO is 12%-13%; ∑SiO2+Al2O3 is 72%-73%.

[0029] In some embodiments of the present application, the ultra-clear float photovoltaic glass further includes the following auxiliary materials, calculated by mass percentage:

[0030] Sodium sulfate 1.0%-3.0%,

[0031] Toner 0%-1.0%,

[0032] Sodium nitrate 0%-3.0%,

[0033] Cerium oxide 0%-0.01%,

[0034] Titanium oxide 0.05%-0.50%.

[0035] In some embodiments of the present application, the ultra-clear float photovoltaic glass includes the following auxiliary materials, calculated by mass percentage:

[0036] Sodium sulfate 1.5%-3.0%,

[0037] Toner 0.5%-1.0%,

[0038] Sodium nitrate 1%-3.0%,

[0039] Cerium oxide 0.005%-0.01%,

[0040] Titanium oxide 0.20%-0.50%.

[0041] In some embodiments of the present application, calculated by mass percentage, the mass percentage of cerium oxide to titanium oxide is (1:8)-(1:15).

[0042] In some embodiments of the present application, the thickness of the ultra-clear float photovoltaic glass is 1.90-2.10 mm;

[0043] And / or, the ultra-clear float photovoltaic glass has a thickness of 1.90-2.10 mm and a light transmittance of 91.90%-92.10%;

[0044] And / or, the ultra-clear float photovoltaic glass has the following optical properties: 96.6≤L*≤96.8, -0.15≤a*≤-0.06, 0.20≤b*≤0.30;

[0045] And / or, the tin count content of the ultra-white float photovoltaic glass is 800-1200.

[0046] To achieve the above objectives, the present application also provides a method for preparing ultra-clear float photovoltaic glass, comprising the following steps:

[0047] Step S10, mixing, melting and clarifying glass raw materials;

[0048] Step S20, flattening and shaping the melted and clarified glass raw material in a tin bath;

[0049] Step S30: annealing the flattened and formed glass raw material.

[0050] In one embodiment of the present application, in step S10, melting and clarification are performed in a melting furnace, and the residual oxygen content of the melting furnace is controlled to be 3.5%-6.5%;

[0051] And / or, in step S10, melting and clarification are performed in a melting furnace, and the air-oil ratio in the melting furnace is (6-14):1;

[0052] and / or, in step S10, melting and clarification are performed in a melting furnace, and the heat load range of the melting furnace is 4%-16%;

[0053] And / or, in the step S10, melting and clarification are performed in a melting furnace, and the residual oxygen content in the melting furnace is 3.5%-6.5%.

[0054] In one embodiment of the present application, in step S20, the molding temperature of the tin bath is 940°C-1100°C;

[0055] And / or, the pulling speed in the flattening forming process is 844m / h-1080m / h;

[0056] And / or, the flow channel temperature in the flattening molding process is 1050° C.-1100° C.;

[0057] And / or, the outlet temperature in the flattening and forming process is 610° C.-620° C.;

[0058] And / or, the flow rate of the protective gas in the flattening forming process is 1390m 3 / h-1680m 3 / h.

[0059] In one embodiment of the present application, in the annealing step, the temperature of the annealing zone is 350°C-550°C.

[0060] Beneficial effects that this application can achieve:

[0061] The present application adjusts the composition of the glass and coordinates the adjustment of the melting process and the tin bath forming process to reduce the proportion of divalent iron in the glass, increase the proportion of trivalent iron, and reduce the tin count in the glass. Ultra-white float photovoltaic glass with high transmittance, good flatness, strong weather resistance, and thin thickness that meets the quality requirements of photovoltaic glass can be produced on an ordinary float production line. The ultra-white float photovoltaic glass can be used in the field of photovoltaic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0063] FIG1 is a schematic flow chart of a method for preparing ultra-white float photovoltaic glass of the present application.

[0064] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0065] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0066] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0067] In this application, the descriptions of "first", "second", etc. are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features specified as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0068] The present application provides an ultra-clear float photovoltaic glass. Calculated by mass percentage, the ultra-clear float photovoltaic glass comprises the following components:

[0069] SiO2: 71%-73%,

[0070] Al2O3: 0.5%-1.5%,

[0071] Fe2O3: 0.008%-0.012%,

[0072] CaO: 7.5%-9.5%,

[0073] MgO: 3.5%-5.0%,

[0074] Na2O: 12.5%-14.0%,

[0075] K2O: 0.2%-1.0%,

[0076] SO3: 0.2%-0.4%,

[0077] Among them, ∑Na2O+K2O is 12.5%-15%; ∑CaO+MgO is 11%-14%; ∑SiO2+Al2O3 is 71.5%-74%.

[0078] In some embodiments, the ultra-clear float photovoltaic glass comprises the following components, calculated by mass percentage:

[0079] SiO2: 71.5%-72.5%,

[0080] Al2O3: 0.8%-1.2%,

[0081] Fe2O3: 0.008%-0.010%,

[0082] CaO: 8.0%-9.0%,

[0083] MgO: 4.0%-5.0%,

[0084] Na2O: 13.0%-14.0%,

[0085] K2O: 0.5%-1.0%,

[0086] SO3: 0.2%-0.3%,

[0087] Among them, ∑Na2O+K2O is 13.5%-14%; ∑CaO+MgO is 12%-13%; ∑SiO2+Al2O3 is 72%-73%.

[0088] In the present application, SiO2 forms an irregular continuous network structure with the structural unit of silicon-oxygen tetrahedron, forming a glass skeleton. In addition, SiO2 can also increase the viscosity of the glass liquid, reduce the crystallization tendency of the glass, and improve the chemical stability and thermal stability of the glass, as well as the mechanical strength and transparency of the glass. When the SiO2 content is too much, it is easy to affect the transparency of the glass, and it is difficult to meet the transparency requirements of ultra-white float photovoltaic glass. However, if the SiO2 content is too little, it will affect the strength of the glass, and it is also difficult to meet the mechanical strength requirements of ultra-white float photovoltaic glass. Therefore, taking all factors into consideration, the SiO2 content in the ultra-white float photovoltaic glass of the present application is controlled at 71%-73%. In some embodiments, calculated by mass percentage, the SiO2 content in the ultra-white float photovoltaic glass can be 71%, 71.3%, 71.5%, 71.6%, 71.8%, 71.9%, 72.0%, 72.1%, 72.4%, 72.5%, 72.8%, 72.9%, 73%, etc. Any value in the range.

[0089] Al2O3 has a tetrahedral structure in glass, which plays a role in repairing the network. It can reduce the tendency of glass to crystallize and the speed of crystallization, and reduce the expansion coefficient of glass. It is an effective glass stabilizing component in glass. However, too much Al2O3 will excessively increase the viscosity of the glass liquid, which is not conducive to the melting and clarification of the glass liquid and the formation of lines. Therefore, it is appropriate to control the Al2O3 content of the present application to 0.5%-1.5%. In some embodiments, calculated by mass percentage, the Al2O3 content in the ultra-white float photovoltaic glass can be any value in the range of 0.5%-1.5%, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, etc.

[0090] In some embodiments, the total mass percentage of SiO2+Al2O3 is 71.5%-74%. Within this range, a higher mechanical strength of the glass can be achieved without placing a heavy burden on the melting and forming process. The melting process has a heavy burden and is likely to affect the forming effect of the glass and then affect its thickness and transmittance.

[0091] Fe2O3 is not only the main colorant of float photovoltaic glass, but the content of Fe2O3 also affects the absorption of visible light by photovoltaic glass. Different valence states have different absorption of light. Trivalent iron ions mainly absorb ultraviolet light, while divalent iron ions mainly absorb visible light, which determines the level of energy conversion of photovoltaic modules and is one of the key factors in measuring whether it can be used as a photovoltaic glass principle. When the Fe2O3 content is too high, greater than 0.012%, it will not only affect the transparency of photovoltaic glass, but also because of its strong absorption effect on the thermal radiation of molten glass, it will easily lead to difficulty in convection of glass liquid in the melting furnace, increasing the difficulty of melting and clarification. Therefore, the Fe2O3 content of this application is In addition, under the condition of a certain iron content, increasing the proportion of trivalent iron ions can reduce the degree of light absorption by iron ions, thereby improving light transmittance. In some embodiments, the content of Fe2O3 in ultra-clear float photovoltaic glass can be 0.008%, 0.009%, 0.010%, 0.011%, 0.012%, etc., calculated by mass percentage. By adjusting the Fe2O3 content as described above, any value in the range can be made to have a higher light transmittance of the ultra-white float photovoltaic glass, while reducing the difficulty of forming and achieving a balance between performance and forming process.

[0092] CaO can reduce the viscosity of molten glass under high temperature conditions, which is beneficial to the melting and clarification of glass. It can increase the viscosity of molten glass under low temperature conditions, which is beneficial to the rapid molding of glass. However, too much CaO can easily increase the tendency of glass crystallization, making the glass brittle, more difficult to mold, poor impact resistance, and poor stability. Therefore, the CaO content of this application is 7.5%-9.5%. In some embodiments, calculated by mass percentage, the CaO content in ultra-white float photovoltaic glass can be 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8.0%, 8.1%, 8.2%, 8.3%, 8.4%, 8.5%, 8.6%, 8.7%, 8.8%, 8.9%, 9.0%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, or any other value within the range of 7.5%-9.5%.

[0093] MgO is a network intermediate oxide. Proper addition of magnesium oxide can reduce the high-temperature viscosity of the glass, reduce the crystallization tendency of the glass, and optimize the comprehensive performance of the glass. In addition, it can also inhibit the mildew of the photovoltaic glass. However, if the MgO content is too high, the viscosity of the glass liquid will increase. Therefore, the MgO content of this application is controlled to be 3.5%-5.0%. In some embodiments, calculated by mass percentage, the MgO content in the ultra-white float photovoltaic glass can be any value in the range of 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0%, etc.

[0094] In some embodiments, the total mass percentage of CaO and MgO is 11%-14%. Within this range, the viscosity of the glass can be reduced to achieve a better melting effect without generating a large number of crystallization defects that affect the transmittance of the glass.

[0095] Na2O is a metal oxide that can lower the melting point of glass, reduce the viscosity of molten glass, and increase its high-temperature fluidity. It is a good flux. However, excessive Na2O content can easily cause sodium ion precipitation, causing alkali precipitation and mold in the glass, and deteriorating the glass's weather resistance. Therefore, the Na2O content is controlled within a range of 12.5%-14.0%. In some embodiments, the Na2O content in ultra-clear float photovoltaic glass can be any value within the range of 12.5%, 12.55%, 12.6%, 12.7%, 12.8%, 12.90%, 13.0%, 13.5%, 13.7%, 13.8%, 13.9%, 14.0%, etc., calculated by mass percentage.

[0096] K2O is also a metal oxide that can produce a mixed alkali effect with Na2O, thereby improving the glossiness of the glass and reducing the precipitation of sodium ions on the glass surface. This improves the disadvantage of photovoltaic glass being prone to mold after long-term storage and improves the weather resistance of the glass. If the K2O content is too low, it will not be conducive to reducing the precipitation of sodium ions on the glass surface; if the K2O content is too high, the thermal expansion coefficient of the photovoltaic glass will increase and the thermal shock resistance will decrease. Therefore, the K2O content of this application is controlled at 0.2%-1.0%. In some embodiments, calculated by mass percentage, the K2O content in the ultra-white float photovoltaic glass can be any value between 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc.

[0097] In some embodiments, ∑Na2O+K2O is 12.5%-15%, which can greatly improve the problem of photovoltaic glass being prone to mold, reduce the melting temperature of the glass, save energy, and at the same time improve the glossiness of the photovoltaic glass to obtain higher light transmittance.

[0098] SO3 is SO3 generated by the oxidation and decomposition of Glauber's salt in the auxiliary material and is stored in the glass body. Glauber's salt is used as a clarifier for glass. If the amount of SO3 converted is too low, the glass will not be clarified well and bubbles cannot be eliminated; if the amount of SO3 converted is too high, there will be an excess of Glauber's salt, forming defects such as Glauber's salt bubbles. Therefore, the SO3 content of this application is controlled at 0.2%-0.4%. In some embodiments, calculated as a percentage by mass, the SO3 content in ultra-white float photovoltaic glass can be any value in the range of 0.2%, 0.21%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.3%, 0.32%, 0.35%, 0.37%, 0.38%, 0.4%, etc.

[0099] In some embodiments, the ultra-clear float photovoltaic glass of the present application contains the following auxiliary materials: Glauber's salt, carbon powder, ammonium nitrate, cerium oxide, and titanium oxide. By designing these auxiliary materials, the proportion of divalent iron in the ultra-clear float photovoltaic glass can be reduced, the proportion of trivalent iron can be increased, and the tin content in the glass can be reduced, resulting in higher transmittance and flatness.

[0100] Among them, calculated by mass percentage, ultra-white float photovoltaic glass contains 1.0%-3.0% Glauber's salt. Glauber's salt, as a glass clarifier, can achieve the purpose of clarifying the glass and improving the transmittance.

[0101] Carbon powder has strong reducing properties and is easily oxidized to generate carbon dioxide. The amount of carbon powder should be minimized to reduce the reducing properties of the glass liquid, thereby reducing the proportion of ferrous ions. Therefore, the amount of carbon powder added in this application is 0-1.0%.

[0102] Cerium oxide and sodium nitrate are both oxidizing auxiliary raw materials that can reduce the proportion of ferrous ions in glass and minimize its light absorption. Excessive amounts of cerium oxide and sodium nitrate can cause the glass to become overly oxidizing, oxidizing the Sn element in the tin bath into SnO, SnO2, and other substances, contaminating the bath and increasing the amount of tin seeping into the surface, thereby reducing light transmittance. Furthermore, the cerium element in cerium oxide can give the glass a yellow tint, so using too much can also reduce the glass's light transmittance. Therefore, calculated by mass percentage, the cerium oxide content is 0-0.01%, for example, the cerium oxide content can be 0%, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, 0.001%, etc.; the sodium nitrate content is 0-3.0%, for example, the sodium nitrate content can be 0%, 1%, 1.5%, 2%, 2.5%, 3%, which can improve the transmittance of ultra-white float photovoltaic glass.

[0103] Titanium oxide is a transition metal and is usually present as Ti in silicate glass. 4+ It exists and can reduce the glass expansion coefficient under high temperature and high alkali conditions and improve the acid resistance of glass. 4+ It appears brownish-yellow in glass and reduces its light transmittance, so excessive use is advised. Furthermore, the combined use of titanium oxide and cerium oxide can further enhance the oxidizability of ultra-clear float photovoltaic glass, reducing the proportion of ferrous ions in the glass and minimizing the glass's absorption of light sources. It can also stabilize ferric ions, preventing them from being reduced to ferrous ions, thereby increasing and stabilizing the light transmittance of ultra-clear float photovoltaic glass. In some embodiments, the content of titanium oxide is 0.05%-0.50% by mass. For example, the content of titanium oxide can be 0.50%, 0.49%, 0.48%, 0.47%, 0.46%, 0.45%, 0.4%, 0.39%, 0.35%, 0.32%, 0.3%, 0.28%, 0.25%, 0.24%, 0.21%, 0.2%, 0.19%, 0.17%, 0.15%, 0.14%, 0.12%, 0.1%, 0.09%, 0.08%, 0.06%, 0.05%, or any other value in the range of 0.05%-0.50%. Titanium oxide within the above content range will not cause the glass to appear brownish-yellow and reduce the light transmittance due to excessive addition. Instead, it can be combined with cerium oxide to further improve the oxidizability of ultra-clear float photovoltaic glass, reduce the proportion of ferrous ions in the glass, and reduce the glass's absorption of light sources. At the same time, it can also stabilize trivalent ferrous ions and prevent trivalent ferrous ions from being reduced to ferrous ions, thereby improving and stabilizing the light transmittance of ultra-clear float photovoltaic glass.

[0104] In some embodiments, the mass ratio of cerium oxide to titanium oxide is (1:8)-(1:15), and can be 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, or 1:15. Within this range, the ferric iron content in the ultra-clear float photovoltaic glass can be significantly increased and stabilized, thereby improving the light transmittance of the glass.

[0105] The ultra-clear float photovoltaic glass of the present application has a thickness of 1.90-2.10 mm. Specifically, the thickness can be any value within the range of 1.90-2.10 mm, such as 1.90 mm, 1.93 mm, 1.95 mm, 1.96 mm, 1.98 mm, 2.00 mm, 2.03 mm, 2.05 mm, 2.08 mm, or 2.10 mm. Ultra-clear float photovoltaic glass within the above thickness range has good light transmittance and can meet the quality requirements of photovoltaic glass.

[0106] By designing the composition and auxiliary materials of the ultra-clear float photovoltaic glass as described above, the light transmittance of the glass can be significantly improved, and its high light transmittance performance can be maintained more stably, and better weather resistance can be obtained. The light transmittance of the ultra-clear float photovoltaic glass with a thickness of 1.90-2.10mm is 91.90%-92.10%. For example, the light transmittance can be any value within the range of 91.90%-92.10%, such as 91.90%, 91.95%, 92.00%, 92.02%, 92.05%, 92.08%, 92.10%, etc.

[0107] In some embodiments, the ultra-clear float photovoltaic glass of the present application also has the following optical properties when the thickness is 1.90-2.10 mm: 96.6≤L*≤96.8, -0.15≤a*≤-0.06, 0.20≤b*≤0.30.

[0108] In some embodiments, the tin count of the ultra-clear float photovoltaic glass of the present application is 800-1200. Under the above tin count conditions, the absorption of light can be reduced, thereby improving the light transmittance of the glass.

[0109] Ultra-white float photovoltaic glass with the above thickness range and optical properties can meet the quality requirements of photovoltaic glass, has high light transmittance, high strength and high durability, and can be used in photovoltaic equipment, especially to provide better protection for solar cells.

[0110] In addition, the present application also provides a method for preparing the ultra-clear float photovoltaic glass as described above, comprising the following steps:

[0111] Step S10, mixing, melting and clarifying glass raw materials;

[0112] Step S20, flattening and shaping the melted and clarified glass raw material in a tin bath;

[0113] Step S30: annealing the flattened and formed glass raw material.

[0114] In step S10, raw materials can be weighed according to the following composition of ultra-clear float photovoltaic glass. Calculated by mass percentage, the components of ultra-clear float photovoltaic glass include:

[0115] SiO2: 71%-73%,

[0116] Al2O3: 0.5%-1.5%,

[0117] Fe2O3: 0.008%-0.012%,

[0118] CaO: 7.5%-9.5%,

[0119] MgO: 3.5%-5.0%,

[0120] Na2O: 12.50%-14.00%,

[0121] K2O: 0.2%-1.0%,

[0122] SO3: 0.2%-0.4%,

[0123] Among them, ∑Na2O+K2O is 12.5%-15%; ∑CaO+MgO is 11%-14%; ∑SiO2+Al2O3 is 71.5-74%.

[0124] In some embodiments, the present application adopts a one-kiln-multiple-line production method, for example, one-kiln-two-line, one-kiln-three-line or one-kiln-four-line, which is more conducive to obtaining ultra-white float photovoltaic glass with a thickness of 1.90-2.10 mm compared to one-kiln-one-line, so as to meet the quality requirements of ultra-white float photovoltaic glass.

[0125] In some embodiments, the glass raw materials are melted and clarified in a furnace, and the residual oxygen content in the furnace is controlled to be 3.5%-6.5%. For example, the residual oxygen content can be any value within the range of 3.5%-6.5%, such as 3.5%, 3.8%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 5.0%, 5.5%, 6.0%, or 6.5%. Properly increasing the residual oxygen content enhances the oxidizing properties of the flame and weakens its reducing properties, thereby reducing the ferrous iron content in the glass and increasing the ferric iron content, thereby improving the transmittance of the finished glass.

[0126] In some embodiments, the glass raw materials are melted and clarified in a furnace with an air-to-oil ratio of (6-14):1. For example, the air-to-oil ratio in the furnace can be 6:1, 7:1, 8:1, 9:1, 9:1, 10:1, 11:1, 12:1, 13:1, or 14:1. By controlling the air-to-oil ratio, the flame reducing properties are controlled, the content of divalent iron ions is reduced, and the content of trivalent iron ions is increased, which helps to improve the transmittance of the finished glass.

[0127] In some embodiments, the depth of the furnace neck water bag is 580-620 mm. For example, the depth can be any value within the range of 580-620 mm, such as 580 mm, 590 mm, 600 mm, 610 mm, or 620 mm. This depth of the neck water bag is beneficial for improving the clarity of the glass raw materials and, in turn, the transparency of the ultra-clear float glass.

[0128] In some embodiments, the forming temperature of the tin bath in step S20 is 940°C-1100°C. For example, the forming temperature can be any temperature within the range of 940°C-1100°C, such as 940°C, 950°C, 960°C, 970°C, 980°C, 990°C, 1000°C, 1050°C, or 1100°C. These forming temperatures can reduce the activity of tin ions in the tin bath, lowering the tin count in the glass and thereby reducing light absorption and improving the transmittance of the glass.

[0129] In some embodiments, the tin bath flattening forming process in step S20 has the following parameters: a pulling speed of 844m / h-960m / h; and / or a flow channel temperature of 1050°C-1100°C; and / or an outlet temperature of 610°C-620°C; and / or a flow rate of the protective gas of 1390m / h. 3 / h-1680m 3 / h.

[0130] At a stretching speed of 844 m / h-1080 m / h, glass with a thickness of 2.0-3.2 mm can be obtained, meeting the requirements of photovoltaic glass. In some embodiments, the stretching speed can be any stretching speed within the range of 844 m / h-1080 m / h, such as 844 m / h, 850 m / h, 860 m / h, 870 m / h, 880 m / h, 890 m / h, 900 m / h, 910 m / h, 920 m / h, 930 m / h, 940 m / h, 950 m / h, 960 m / h, 1000 m / h, or 1080 m / h.

[0131] The tin bath flow temperature is 1050°C-1100°C, the molding temperature is 940°C-1100°C, and the outlet temperature is 610°C-620°C, which is more conducive to glass molding. In some embodiments, the tin bath flow temperature can be any temperature in the range of 1050°C-1100°C, such as 1050°C, 1065°C, 1070°C, 1080°C, 1090°C, 1100°C; the molding temperature can be any temperature in the range of 940°C-1100°C, such as 940°C, 950°C, 960°C, 970°C, 980°C, 990°C, 1000°C, 1050°C, 1060°C, 1096°C; and the outlet temperature can be any temperature in the range of 610°C-620°C, such as 615°C, 618°C, 620°C.

[0132] The flow rate of the shielding gas is 1390m3 / h-1680m3 / h. In some embodiments, the flow rate of the shielding gas can be 1390m3 / h. 3 / h、1400m 3 / h、1450m 3 / h、1480m 3 / h、1490m 3 / h、1500m 3 / h、1550m 3 / h、1580m 3 / h、1600m 3 / h、1620m 3 / h、1650m 3 / h、1670m 3 / h、1680m 3 / h etc. 1390m 3 / h-1680m 3 Any flow rate within the range of 1000 / h can reduce the tin count in the glass, thereby reducing the absorption of light and enhancing the light transmittance of the glass.

[0133] In some embodiments, the protective gas may be nitrogen, which can provide a reducing atmosphere and isolate oxygen in the air from contacting tin at high temperatures to prevent tin from being oxidized to form impurities, thereby affecting the light transmittance of the photovoltaic glass.

[0134] In some embodiments, hydrogen can be added during the tin bath flattening and forming process. Hydrogen can assist the above protective gases in providing a reducing atmosphere and further reduce the impact of air entry on the forming of the glass. Specifically, the flow rate of hydrogen is 108m 3 / h-113m 3 / h. At high temperatures, it works together with the above-mentioned protective gas to isolate the oxygen in the air from contacting tin, preventing the tin from being oxidized to form impurities, which in turn affects the light transmittance of the photovoltaic glass.

[0135] In some embodiments, step S30 completes annealing treatment in an annealing furnace. The annealing process can be divided into a uniform heating zone A, an important annealing zone B, a post-annealing zone C, a hot air circulation cooling zone Ret, and a forced cooling zone F. The temperature of the annealing zone A is 539°C-545°C, the temperature of the annealing zone B is 480°C, the temperature of the annealing zone C is 335-347°C, the temperature of the Ret zone is 250°C-260°C, and the temperature of the F zone is 100°C-115°C.

[0136] Annealing zone A can make the glass raw materials heated evenly; annealing zone B is the main annealing zone to eliminate the permanent stress of the glass. Therefore, annealing zone B can be extended to annealing zone B1, annealing zone B2 and other annealing zones, which is beneficial to eliminate most of the permanent stress of the glass; and annealing zone C can eliminate the remaining permanent stress of the glass. At this time, the Ret zone is cooled by hot air circulation to eliminate the temporary stress of the glass, and then cooled in zone F.

[0137] Photovoltaic glass is an essential material for photovoltaic modules. It is usually used as the cover glass of crystalline silicon single-glass modules, the cover and back glass of double-glass modules, and the substrate glass of thin-film modules.

[0138] Therefore, the present application also provides a photovoltaic module, which includes the ultra-white float photovoltaic glass as described above and has at least all the beneficial effects of the ultra-white float photovoltaic glass of the present application.

[0139] Furthermore, the present application also provides a photovoltaic system, which includes the photovoltaic assembly as described above and has at least all the beneficial effects of the ultra-white float photovoltaic glass of the present application.

[0140] The technical solution of the present application is further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present application and are not used to limit the present application.

[0141] Example 1

[0142] In step S10, glass raw materials are weighed according to the composition of the ultra-clear float photovoltaic glass designed in Table 1 and mixed uniformly; the mixed glass raw materials are put into a melting furnace according to the conditions in Table 2, melted, and then clarified; the float melting capacity of this embodiment is 1,000 tons, and the melting method is one furnace and two lines, with a melting capacity of 350 tons per line.

[0143] Step S20, flattening and shaping the glass raw material that has been melted and clarified in step S20 in a tin bath according to the processing conditions in Table 2;

[0144] Step S30: performing annealing treatment according to the processing conditions of Condition 1 in Table 3 to obtain ultra-white float photovoltaic glass.

[0145] Example 1 obtained 5 groups of different ultra-white float photovoltaic glasses.

[0146] Comparative Example 1

[0147] Comparative Example 1 The composition of the glass is designed in Table 1, and a finished glass is prepared by referring to the preparation method of Example 1.

[0148] Performance Testing

[0149] The optical properties of the glasses obtained in Example 1 and Comparative Example 1 were measured, as shown in Table 4.

[0150] Table 1 Composition of the glasses obtained in Example 1 and Comparative Example 1 (mass percentage)

[0151] Table 2 Process parameters of steps S10 to S30 of Example 1 and Comparative Example 1

[0152] Table 3 Comparison of properties of the glasses obtained in Example 1 and Example 1

[0153] It can be seen from Tables 1 to 3 above that the ultra-clear float photovoltaic glass obtained in Example 1 has a thickness between 1.90 and 2.10 mm and a transmittance above 91.6%, which can meet the requirements of photovoltaic glass.

[0154] However, the comparative component 1 in comparative example 1 does not meet ∑SiO2+Al2O3=71.5%-74%, and reaches 74.8%, which puts a heavy burden on the melting and molding process of the glass, affects the molding effect of the glass, and then affects the thickness and transmittance of the glass.

[0155] Comparative Example 1 and Component 2 do not meet the requirement of ΣCaO+MgO=11%-14%, reaching 15.3%, resulting in crystallization defects and affecting the light transmittance of the glass.

[0156] Comparative Example 1, compared with component 3, does not meet ∑Na2O+K2O=12.5%-15%, and is only 11.692%. It is difficult to improve the technical problem of the glass being prone to mold, which in turn affects the light transmittance of the glass. Moreover, in the melting stage of the glass, it is difficult to lower its melting temperature, which is not conducive to improving the glossiness of the glass. The light transmittance of the obtained glass is slightly low, which is difficult to meet the requirements of photovoltaic glass.

[0157] Example 2

[0158] Example 2 Based on component 1 of Example 1, the design composition of the glass was determined, and the glass was prepared according to the preparation method of Example 1. The effects of adding sodium sulfate, carbon powder, sodium nitrate, cerium oxide, and titanium oxide to the glass raw materials on the glass properties were compared. The addition of auxiliary materials is specifically shown in Table 4.

[0159] Comparative Example 2

[0160] Comparative Example 2 refers to Example 2, except that the addition of auxiliary materials is different, as shown in Table 4.

[0161] Performance Testing

[0162] The optical properties of the glasses obtained in Example 2 and Comparative Example 2 were measured, as shown in Table 5.

[0163] Table 4 Excipient ratios of Example 2 and Comparative Example 1

[0164] Table 5 Comparison of properties of the glasses obtained in Example 2 and Comparative Example 2

[0165] As shown in Tables 4 and 5, reducing the amount of auxiliary carbon powder from 1% in Formula 1 to 0% in Formula 2, a 1% reduction, can increase the transmittance of the glass from 92.10% to 92.15%, an improvement of 0.05%. In Comparative Example 2, in which Formulas 1 and 2 are omitted, respectively, no titanium oxide and cerium oxide are added, the trivalent iron ions in the glass are unstable and easily reduced to divalent iron ions, which affects the optical properties of the glass. The transmittance of the glass is only 89.51%, which is difficult to meet the requirements of photovoltaic glass. It can be seen that the addition of titanium oxide and cerium oxide is beneficial to improving and stabilizing the transmittance of the glass, and the combined use effect is better.

[0166] Example 3

[0167] Example 3 Based on component 1 of Example 1, the design composition of the glass was determined, and the effects of the melting process in step S10 on the glass properties were compared. The specific melting process is shown in Table 6.

[0168] Comparative Example 3

[0169] Comparative Example 3 refers to Example 3, except for the melting process in step S10, as shown in Table 6.

[0170] Performance Testing

[0171] The optical properties of the glasses obtained in Example 3 and Comparative Example 3 were measured, as shown in Table 7.

[0172] Table 6 Melting and clarification process parameters of step S10 of Example 3 and Comparative Example 3

[0173] Table 7 Comparison of properties of the glasses obtained in Example 3 and Comparative Example 3

[0174] Tables 6 and 7 show that Example 3, by adjusting the air-to-oil ratio to control the residual oxygen content, can control the flame's reducing properties, and thus adjust the glass's transmittance. When the residual oxygen content increases by 1%, the transmittance increases by 0.08%. In Comparative Example 3, in Comparative Condition 1, the air-to-oil ratio is 3%-5.5%, and the residual oxygen content is also low. The resulting glass has unsatisfactory optical properties, with a transmittance of only 89.51%, which fails to meet the requirements for photovoltaic glass. Furthermore, in Comparative Example 3, in Comparative Condition 2, the depth of the neck water bag is only 500 mm, resulting in poor glass clarification, which in turn affects the transmittance of the finished glass, resulting in a transmittance of only 89.82%, which falls short of the requirements for photovoltaic glass.

[0175] Example 4

[0176] Example 4 Based on component 1 of Example 1, the design composition of the glass is determined, and the effects of the tin bath process parameters of step S20 and the annealing parameters of step S30 on the optical properties of the glass are compared, as shown in Table 8.

[0177] Performance Testing

[0178] The tin count and optical properties of the glass obtained in Example 4 were measured, as shown in Table 9.

[0179] Table 8 Tin bath process parameters of step S20 and annealing parameters of step S30 in Example 4

[0180] Table 9 Properties of the glass obtained in Example 4

[0181] From Table 8 to Table 9, we can see that the amount of protective gas is from 1300M 3 / H gradually increased to 1700M 3 / H, every increase of 100NM 3 / H, the tin count is reduced by about 90-110, and the transmittance can be increased by 0.02%-0.05%. It can be seen that by increasing the amount of shielding gas, reducing the tin count, and then improving the transmittance of the glass.

[0182] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An ultra-clear float photovoltaic glass, wherein: Calculated by mass percentage, the ultra-clear float photovoltaic glass includes the following components: SiO2: 71%~73%, Al2O3: 0.5%~1.5%, Fe2O3: 0.008%~0.012%, CaO: 7.5% to 9.5%, MgO: 3.5%~5.0%, Na2O: 12.5%~14.0%, K2O: 0.2%~1.0%, SO3: 0.2%~0.4%, Among them, ∑Na2O+K2O is 12.5%~15%; ∑CaO+MgO is 11%~14%; ∑SiO2+Al2O3 is 71.5%~74%.

2. The ultra-clear float photovoltaic glass according to claim 1, wherein: Calculated by mass percentage, the ultra-clear float photovoltaic glass includes the following components: SiO2: 71.5%~72.5%, Al2O3: 0.8%~1.2%, Fe2O3: 0.008%~0.010%, CaO: 8.0% to 9.0%, MgO: 4.0%~5.0%, Na2O: 13.0%~14.0%, K2O: 0.5%~1.0%, SO3: 0.2%~0.3%, Among them, ∑Na2O+K2O is 13.5%~14%; ∑CaO+MgO is 12%~13%; ∑SiO2+Al2O3 is 72%~73%.

3. The ultra-clear float photovoltaic glass according to claim 1, wherein: Calculated by mass percentage, the ultra-clear float photovoltaic glass includes the following auxiliary materials: Sodium Sulfate 1.0%~3.0%, Carbon powder 0%~1.0%, Sodium nitrate 0%~3.0%, Cerium oxide 0%~0.01%, Titanium oxide 0.05%~0.50%.

4. The ultra-clear float photovoltaic glass according to claim 3, wherein: Calculated by mass percentage, the ultra-clear float photovoltaic glass also includes the following auxiliary materials: Sodium Sulfate 1.5%~3.0%, Carbon powder 0.5%~1.0%, Sodium nitrate 1%~3.0%, Cerium oxide 0.005%~0.01%, Titanium oxide 0.20%~0.50%.

5. The ultra-clear float photovoltaic glass according to claim 4, wherein: Calculated by mass percentage, the mass percentage of the cerium oxide to the titanium oxide is (1:8) to (1:15).

6. The ultra-clear float photovoltaic glass according to any one of claims 1 to 5, wherein: The thickness of the ultra-clear float photovoltaic glass is 1.90 to 2.10 mm; And / or, the ultra-clear float photovoltaic glass has a thickness of 1.90 to 2.10 mm and a light transmittance of 91.90% to 92.10%; And / or, the ultra-clear float photovoltaic glass has the following optical properties: 96.6≤L*≤96.8, -0.15≤a*≤-0.06, 0.20≤b*≤0.30; And / or, the tin count of the ultra-white float photovoltaic glass is 800-1200.

7. A method for preparing the ultra-clear float photovoltaic glass according to any one of claims 1 to 6, wherein: The following steps are involved: Step S10, mixing, melting and clarifying glass raw materials; Step S20, flattening and shaping the melted and clarified glass raw material in a tin bath; Step S30, annealing the flattened glass raw material.

8. The method for preparing ultra-clear float photovoltaic glass according to claim 7, wherein: In the step S10, melting and clarification are performed in a melting furnace, and the residual oxygen content of the melting furnace is controlled to be 3.5% to 6.5%; And / or, in the step S10, melting and clarification are performed in a melting furnace, and the air-oil ratio in the melting furnace is (6-14):1; And / or, in step S10, melting and clarification are carried out in a melting furnace, and the heat load in the melting furnace The load range is 4% to 16%; And / or, in the step S10, melting and clarification are performed in a melting furnace, and the residual oxygen content in the melting furnace is 3.5% to 6.5%.

9. The method for preparing ultra-clear float photovoltaic glass according to claim 7, wherein: In the step S20, the molding temperature of the tin bath is 940°C to 1100°C; And / or, the pulling speed in the flattening forming process is 844m / h to 1080m / h; And / or, the flow channel temperature in the flattening molding process is 1050° C. to 1100° C.; And / or, the outlet temperature in the flattening and forming process is 610° C. to 620° C.; And / or, the flow rate of the protective gas in the flattening forming process is 1390m 3 / h~1680m 3 / h.

10. The method for preparing ultra-clear float photovoltaic glass according to claim 7, wherein: In the annealing step, the temperature of the annealing zone is 350°C to 550°C.

11. A photovoltaic module, wherein: The photovoltaic module comprises the ultra-white float photovoltaic glass according to any one of claims 1 to 6.

12. A photovoltaic system, wherein: The photovoltaic system comprises the photovoltaic module according to claim 11.

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