Chemically strengthened glass, preparation method thereof and photovoltaic module

Abstract

The invention discloses chemically strengthened glass, a preparation method thereof and a photovoltaic module, and belongs to the technical field of chemically strengthened glass. The chemically strengthened glass comprises the following components in percentage by mass: 55-65% of SiO2, 15-25% of Al2O3, 2-4% of Li2O, 9-12% of Na2O, 1-3% of B2O3 and 1-3% of rare earth oxide, the chemical tempering effect and the chemical tempering efficiency of the glass are strengthened by adjusting the composition of the glass, so that the glass has the light and thin characteristics after being tempered, the thickness can be less than or equal to 2.0 mm, and the glass has the characteristics of light weight, high strength, high hardness and the like. Compared with the traditional glass with the thickness of 2.0 mm, the glass has the advantages of high light transmittance, high mechanical strength and high weather resistance, can obtain the advantages that the light transmittance is greater than or equal to 94% and the breaking strength is greater than or equal to 600Mpa after being coated, and is suitable for the fields of photovoltaic modules, distributed photovoltaics and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of chemically strengthened glass, and in particular to chemically strengthened glass, a preparation method thereof, and a photovoltaic module. Background Art

[0002] Currently, traditional photovoltaic glass is typically produced through a physical tempering process, with a thickness typically ≥2.0mm. This leads to issues such as heavy weight and limited light transmittance. Glass produced using conventional chemical tempering processes also suffers from an insufficiently deep surface compressive stress layer, resulting in poor resistance to wind and sand abrasion. Furthermore, the demand for high light transmittance limits the addition of certain metal oxides to the glass components, resulting in suboptimal overall performance. Summary of the Invention

[0003] The main purpose of the present invention is to provide a chemically strengthened glass, a preparation method thereof, and a photovoltaic module, to solve the technical problems of the existing chemically strengthened glass, such as insufficient depth of the surface compressive stress layer and unsatisfactory comprehensive performance of light transmittance, mechanical strength, and weather resistance.

[0004] To achieve the above object, the present invention provides a chemically strengthened glass, which comprises the following components, calculated by mass percentage:

[0005] SiO2: 55% to 65%,

[0006] Al2O3: 15% to 25%,

[0007] Li2O: 2% to 4%,

[0008] Na2O: 9% to 12%,

[0009] B2O3: 1% to 3%,

[0010] Rare earth oxides: 1% to 3%.

[0011] In some embodiments of the present invention, calculated as a mass percentage, the range of (Al2O3+B2O3) / Li2O is 4 to 11.5.

[0012] In some embodiments of the present invention, the rare earth oxide includes at least one of La2O3 and Y2O3.

[0013] The present invention also provides a chemically strengthened glass, which includes the chemically strengthened glass described above.

[0014] In some embodiments of the present invention, the thickness of the chemically strengthened glass is ≤2.0 mm;

[0015] And / or, the surface compressive stress of the chemically strengthened glass is ≥650 MPa;

[0016] And / or, the flexural strength of the chemically strengthened glass is ≥550 MPa;

[0017] And / or, the transmittance attenuation of the chemically strengthened glass in a UV aging test (DH1000) is ≤1.5%;

[0018] And / or, the light transmittance of the chemically strengthened glass is ≥91.5%;

[0019] And / or, the chemically strengthened glass has a light transmittance of ≥94% and a flexural strength of ≥600 MPa after coating.

[0020] The present invention also provides a method for preparing the chemically strengthened glass as described above, comprising the following steps:

[0021] Weighing glass raw materials according to the composition of the chemically strengthened glass, melting the glass raw materials to obtain glass liquid, and forming and annealing the glass liquid to obtain a glass raw sheet;

[0022] After polishing and cleaning the glass original sheet, it is immersed in molten salt to perform a first-stage ion exchange treatment to obtain the chemically strengthened glass.

[0023] In some embodiments of the present invention, in the annealing step, the annealing temperature is 600° C. to 700° C., and the annealing time is 2 h to 3 h;

[0024] And / or, the acid resistance grade of the glass sheet is greater than or equal to grade 1;

[0025] And / or, the moisture resistance grade of the glass sheet is above HGB2.

[0026] In some embodiments of the present invention, after the polishing process, the surface roughness of the glass sheet is Ra≤0.1 μm;

[0027] And / or, in the step of the first-stage ion exchange, the temperature range of the first-stage ion exchange is 440° C. to 450° C., and the time of the first-stage ion exchange is 4 hours to 10 hours;

[0028] And / or, the molten salt includes KNO3.

[0029] In some embodiments of the present invention, after the first stage ion exchange treatment is completed, a pulsed electric field is applied to the molten salt to perform a second stage ion exchange treatment.

[0030] In some embodiments of the present invention, the voltage range of the pulsed electric field is 100V to 150V; and / or the frequency range of the pulsed electric field is 10Hz to 15Hz.

[0031] The beneficial effects that can be achieved by the present invention are:

[0032] By adjusting the composition of the glass, the present invention can enhance the tempering effect and efficiency of the glass and deepen the depth of ion exchange, which can even reach 45μm to 65μm. This allows the tempered chemically strengthened glass to be lightweight and thin, with a thickness of ≤2.0mm, and a weight reduction of more than 60% compared to traditional 2.0mm thick glass. Furthermore, the present invention has the advantages of high light transmittance, high mechanical strength, and high weather resistance, and can meet the following requirements: surface compressive stress ≥650MPa, flexural strength ≥550MPa, and transmittance attenuation ≤1.5% in a UV aging test (DH1000). After coating, it can achieve a light transmittance ≥94% and a flexural strength ≥600Mpa. Therefore, the present invention can be used as photovoltaic glass in photovoltaic modules, distributed photovoltaics, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention 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 invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0034] Figure 1 The figure is a schematic flow chart of a method for preparing chemically strengthened glass according to the present invention.

[0035] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0036] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] In the present invention, descriptions such as "first" and "second" 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, features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions of various embodiments may be combined with each other, but this must be based on the fact that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0039] The present invention provides a chemically strengthened glass. Calculated by mass percentage, the chemically strengthened glass comprises the following components: SiO2: 55% to 65%, Al2O3: 15% to 25%, Li2O: 2% to 4%, Na2O: 9% to 12%, B2O3: 1% to 3%, and rare earth oxide: 1% to 3%.

[0040] By adjusting the composition of the glass, the present invention can enhance the tempering effect and efficiency of the glass and deepen the depth of ion exchange, which can even reach 45μm to 65μm. This allows the tempered chemically strengthened glass to be lightweight and thin, with a thickness of ≤2.0mm, and a weight reduction of more than 60% compared to traditional 2.0mm thick glass. Furthermore, the present invention has the advantages of high light transmittance, high mechanical strength, and high weather resistance, and can meet the following requirements: surface compressive stress ≥650MPa, flexural strength ≥550MPa, and transmittance attenuation ≤1.5% in a UV aging test (DH1000). After coating, it can achieve a light transmittance ≥94% and a flexural strength ≥600Mpa. Therefore, the present invention can be used as photovoltaic glass in photovoltaic modules, distributed photovoltaics, and other fields.

[0041] The chemically strengthened glass of the present invention contains rare earth oxides, which can expand the network gaps in the glass structure and promote the K + and Li in glass + 、Na + The exchange efficiency and exchange effect are improved, the depth of ion exchange is deepened, and the exchange depth can even reach 45μm~65μm, thereby solving the problem of insufficient surface compressive stress depth of glass after ion exchange treatment in the tempering stage, so that the glass can obtain stronger surface compressive stress and flexural strength, effectively resist wind and sand wear, and extend the service life of the glass. Moreover, during the ion exchange process, the composition of the glass remains almost unchanged, that is, on the basis of ensuring that the glass obtains good light transmittance, the mechanical properties of the glass are improved, and a stronger resistance to wind and sand wear is obtained. The choice of glass components is relaxed, and the comprehensive performance of the glass is further improved, making it suitable for photovoltaic modules, distributed photovoltaics and other fields.

[0042] In the present invention, if the rare earth oxide content in the glass is too low, it is difficult to achieve the purpose of improving the ion exchange effect, and if the content is too high, it is easy to increase the brittleness of the glass. In order to make the glass achieve a balance between stress depth, mechanical strength, transmittance and process stability, the content of rare earth oxide in the photovoltaic glass of the present invention is 1% to 3%, which can be 1%, 1.5%, 2%, 2.5%, 3%, etc.

[0043] In some embodiments, the rare earth oxide includes at least one of La2O3 and Y2O3. The above rare earth oxides can expand the network gaps in the glass structure, promote the ion exchange efficiency and exchange depth between K+ and Li+ and Na+ in the glass, and the exchange depth can even reach 45μm to 65μm, thereby improving the ion exchange effect, enabling the glass to obtain stronger surface compressive stress and flexural strength, effectively resist wind and sand wear, and extend the service life of the glass.

[0044] Chemically strengthened glass contains SiO2. When the SiO2 content is less than 50%, it is easy to affect the chemical stability of the glass. When the content is above 65%, the glass raw materials are difficult to melt. Therefore, the mass percentage of SiO2 in chemically strengthened glass is 55% to 65%, and can be 55%, 57%, 60%, 62%, 63%, 65%, etc.

[0045] Chemically strengthened glass contains Al2O3. When Al2O3 replaces SiO2, the molecular volume of the glass increases, expanding the voids in the glass network structure and facilitating the diffusion of alkali ions. This accelerates ion exchange during the process. The mass percentage of Al2O3 in chemically strengthened glass ranges from 15% to 25%, with options ranging from 15%, 18%, 20%, 22%, 23%, to 25%, and so on.

[0046] Chemically strengthened glass contains LiO2, which can partially replace Na2O, thereby reducing the density of the glass and making it lighter. The mass percentage of LiO2 in chemically strengthened glass ranges from 2% to 4%, and can be 2%, 2.5%, 3%, 3.5%, 4%, etc.

[0047] Chemically strengthened glass contains Na2O. Acting as a flux, Na2O can lower the melting temperature of SiO2 and improve production efficiency. It also regulates the thermal expansion coefficient, creating stronger surface compressive stress during rapid cooling, enhancing mechanical strength. However, Na2O content must be controlled to avoid compromising chemical stability or triggering high-temperature alkali volatilization to ensure the durability and safety of chemically strengthened glass. Therefore, the mass percentage is controlled to be between 9% and 12%, and can be 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, and so on.

[0048] Chemically strengthened glass contains B2O3, which can work synergistically with Al2O3 to adjust the grid structure of the glass. 3+ As a network former, B 3+ As an intermediate, it increases the structural density of the glass and improves its mechanical strength. The mass percentage of B2O3 in chemically strengthened glass is 1% to 3%, and can be 1%, 2%, 3%, etc.

[0049] In the present invention, the interaction between Al2O3, B2O3, and Li2O influences the properties of the glass. Al2O3 and B2O3 strengthen the glass network structure, improving mechanical strength and chemical stability, while Li2O reduces melt viscosity and adjusts the thermal expansion coefficient. In some embodiments, the ratio (Al2O3 + B2O3) / Li2O, calculated as a mass percentage, ranges from 4 to 11.5, and can be 4, 4.2, 4.3, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.2, 11.4, 11.5, etc. This ratio range ensures that the glass has both good formability and anti-devitrification ability, while balancing thermal expansion behavior to adapt to the tempering process and avoid structural weakening or reduced chemical durability due to excessive Li2O. In addition, this ratio can also synergize the modification effect of rare earth oxides, so that the glass has excellent processing adaptability while maintaining high strength, which is beneficial to improving the structural density of the glass and improving the mechanical properties of the glass.

[0050] The present invention further provides a chemically strengthened glass, which includes the above-mentioned chemically strengthened glass and can be obtained by subjecting the above-mentioned chemically strengthened glass to a tempering treatment.

[0051] In some embodiments, the thickness of the chemically strengthened glass is ≤2.0 mm, and may be 1.80 mm to 1.1 mm, which can meet the thickness requirements of photovoltaic glass.

[0052] In some embodiments, the chemically strengthened glass exhibits a surface compressive stress of 650 MPa or greater, a flexural strength of 550 MPa or greater, and a light transmittance loss of 1.5% or less in a UV aging test (DH1000) at a thickness of 0.8 mm to 1.1 mm. DH1000 refers to continuous testing for 1000 hours under high temperature and high humidity conditions, with the high temperature being 85°C and the high humidity being 85%.

[0053] In some embodiments, the light transmittance of the chemically strengthened glass is greater than or equal to 91.5%.

[0054] In some embodiments, chemically strengthened glass can achieve a light transmittance of over 94% and a flexural strength of over 600 MPa after coating.

[0055] The present invention also provides a method for preparing the above-mentioned chemically strengthened glass, referring to Figure 1 , including the following steps:

[0056] S10, weighing glass raw materials according to the composition of chemically strengthened glass, melting the glass raw materials to obtain glass liquid, and forming and annealing the glass liquid to obtain a glass raw sheet;

[0057] S20, after polishing and cleaning the original glass sheet, immersing it in molten salt to perform a first-stage ion exchange treatment to obtain chemically strengthened glass.

[0058] In some embodiments, in the melting step, the melting temperature ranges from 1500° C. to 1600° C., which is beneficial for promoting the melting and mixing of the glass raw materials.

[0059] In some embodiments, the molten glass is tape-cast to obtain a desired thickness.

[0060] In some embodiments, the annealing temperature ranges from 600° C. to 700° C., and the annealing time ranges from 2 h to 3 h.

[0061] In some embodiments, the acid resistance level of the glass sheet obtained after the treatment in step S10 is greater than or equal to level 1. It can be understood that the standard for acid resistance greater than or equal to level 1 is as follows: the glass is immersed in a 6 mol / L hydrochloric acid solution at 80°C for 24 hours, and the mass loss is ≤0.1 mg / cm 2 .

[0062] In some embodiments, the moisture resistance level of the glass sheet obtained in step S10 is above HGB2. It can be understood that the standard for the moisture resistance level above HGB2 is as follows: the glass is immersed in water at 98°C for 1 hour, and the amount of alkali dissolved in the glass is between 31μg / g and 62μg / g.

[0063] After obtaining the glass original sheet, the present invention polishes the glass original sheet before ion exchange treatment, which is beneficial to improving the roughness of the glass surface, obtaining an optical-grade mirror effect, and making the glass suitable for the photovoltaic field.

[0064] In some embodiments, during the polishing step, the polishing material includes corundum, and natural corundum may be selected to grind and polish the glass sheet to improve the roughness of the glass surface to achieve an optical-grade mirror effect.

[0065] In some embodiments, during the polishing step, the polishing material includes at least one of cerium oxide and zirconium oxide in addition to corundum. Adding cerium oxide and / or zirconium oxide as polishing materials is beneficial for improving the roughness of the glass surface and obtaining an optical-grade mirror effect.

[0066] In some embodiments, after the glass original sheet is polished, the surface roughness Ra is ≤ 0.1 μm, which is closer to an optical-grade mirror effect.

[0067] After polishing, the original glass sheet is also cleaned to reduce the impact of residue on the ion exchange efficiency and effect. In some embodiments, it can be cleaned with clean water.

[0068] After being polished and cleaned, the original glass sheets are also edge-grinded to reduce stress concentration at the edges, improve the mechanical strength of the glass, prevent edge chipping during the chemical tempering process of ion exchange, and achieve the preparation of thin and light glass, making the glass suitable for the photovoltaic field.

[0069] In the present invention, the process of immersing the treated glass sheet into molten salt for ion exchange is a process of chemically tempering the glass, which promotes K + and Na + 、Li + The exchange of ions forms a dense compression layer on the glass surface, increases the compressive stress on the glass surface, and improves the bending strength, impact resistance and wear resistance of the glass. Moreover, when the glass is tempered by chemical tempering, ion exchange is generally carried out on the surface of the glass without changing the components of the glass body. Compared with the physical tempering method through high-temperature heating, it can better ensure the high transmittance of the glass. Moreover, while ensuring the light transmittance of the glass, the mechanical properties of the chemically strengthened glass can be improved by adjusting the components of the chemically strengthened glass, so that the glass can meet the requirements of the photovoltaic field.

[0070] In some embodiments, the molten salt includes KNO3, and the K+ in the molten salt can react with the Na + , L i+ The exchange forms a dense compression layer on the glass surface, increases the compressive stress on the glass surface, and improves the bending strength, impact resistance and wear resistance of the glass.

[0071] In some embodiments, the mass concentration of KNO3 is above 99%.

[0072] In some embodiments, the temperature for immersing the glass sheet in the molten salt for the first stage of ion exchange is 440° C. to 450° C., and the time is 5 hours to 6 hours.

[0073] In some embodiments, after completing the first stage of ion exchange treatment, a pulsed electric field is applied to the molten salt to carry out the second stage of ion exchange treatment. The pulsed electric field promotes the secondary exchange of Li+, Na+ and K+, which can make the ion exchange more thorough, make the stress distribution of the glass more uniform, and improve the edge strength of the glass, thereby avoiding the problem of edge chipping when cutting the glass.

[0074] In some embodiments, after the second stage ion exchange treatment, the ion exchange depth can range from 45 μm to 65 μm, and the compressive stress of the obtained glass can be ≥650 MPa.

[0075] In some embodiments, the temperature of the first stage ion exchange is 400°C to 440°C, and the exchange time is 1h to 2h, which is beneficial to promote Na + 、Li + and K + The secondary exchange makes the ion exchange more thorough, the stress distribution of the glass more uniform, and the edge strength of the glass is improved, avoiding the problem of edge chipping when the glass is cut. In the present invention, by applying a pulsed electric field to drive the ion exchange, the ion exchange depth can be increased to 45μm to 65μm.

[0076] In some embodiments, the voltage range of the pulsed electric field is 100V to 150V, and can be 100V, 110V, 120V, 130V, 140V, 150V, etc.

[0077] In some embodiments, the frequency of the pulsed electric field is 10 Hz to 15 Hz.

[0078] The technical solutions of the present invention are 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 invention and are not used to limit the present invention.

[0079] Example 1

[0080] The preparation method of photovoltaic glass in Example 1 is as follows:

[0081] S10. Weigh glass raw materials according to the composition of chemically strengthened glass in Table 1. Melt the glass raw materials at 1650° C. for 3 h to obtain molten glass. The molten glass is tape-casted to a thickness of 1.0 mm, and then annealed at 600° C. for 2 h to obtain a raw glass sheet.

[0082] S20. The glass sheet is ground and polished with natural corundum to a surface roughness of Ra ≤ 0.1 μm. After cleaning and edge grinding, the glass sheet is immersed in a molten salt of KNO3 and subjected to a first-stage ion exchange treatment at 450°C for 6 hours. A pulsed electric field is then added to the molten salt with a voltage of V100 and a frequency of 10 Hz. A second-stage ion exchange treatment is performed at 400°C for 1 hour to obtain chemically strengthened glass.

[0083] Example 2 to Example 10

[0084] Chemically strengthened glass was prepared in Examples 2 to 10 by referring to the method of Example 1, but the composition of the glass was different, as shown in Table 1.

[0085] Comparative Example 1

[0086] Comparative Example 1 Chemically strengthened glass was prepared by referring to the method of Example 1, except that the glass components of Comparative Example 1 were different, as shown in Table 1.

[0087] The properties of the chemically strengthened glasses of Examples 1 to 10 and Comparative Example 1 were measured, as shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091] The chemically strengthened glasses of Examples 1 to 10 all achieved good surface compressive stress, flexural strength, and light transmittance, with a stress layer depth of more than 42.1 μm. They achieved both good mechanical properties and light transmittance, and had the advantages of being lightweight, thin, and weather-resistant, making them suitable for the photovoltaic glass field.

[0092] The components of the chemically strengthened glass of Comparative Example 1 are not within the requirements of the present invention, and its surface compressive stress, stress layer depth, flexural strength and light transmittance are slightly inferior.

[0093] Example 11 to Example 14

[0094] Chemically strengthened glass was prepared in Examples 11 to 14 using the same method as in Example 3. However, the glass components in Examples 11 to 14 were the same, but the preparation methods were different, as shown in Table 2. A SiO2 / TiO2 composite coating was then applied to the chemically strengthened glass obtained in Examples 11 to 14, resulting in a finished product having a thickness of 1.1 mm.

[0095] Example 15

[0096] In Example 15, chemically strengthened glass was prepared and coated with a film according to the method of Example 11, except that the second stage ion exchange treatment was not performed in Example 15.

[0097] The properties of the chemically strengthened glasses after coating in Examples 11 to 15 were measured, as shown in Table 2.

[0098] Table 2

[0099]

[0100] As can be seen from Table 2, the transmittance of the chemically strengthened glass of the present invention can be increased from 91.5% to 94% after coating, and it also has good mechanical properties and aging resistance.

[0101] Examples 11 to 14 all carried out the first stage ion exchange and the second stage ion exchange. The increase of the pulsed electric field further promoted the ion exchange, and the performance of the obtained glass was better than that of the glass of Example 15 which did not carry out the second stage ion exchange.

[0102] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A chemically strengthened glass, characterized in that: Calculated by mass percentage, the chemically strengthened glass includes the following components: SiO2: 55% to 65%, Al2O3: 15% to 25%, Li2O: 2% to 4%, Na2O: 9% to 12%, B2O3: 1% to 3%, Rare earth oxides: 1% to 3%.

2. The chemically strengthened glass according to claim 1, wherein Calculated by mass percentage, the range of (Al2O3+B2O3) / Li2O is 4 to 11.

5.

3. The chemically strengthened glass according to claim 1, wherein The rare earth oxide includes at least one of La2O3 and Y2O3.

4. The chemically strengthened glass according to claim 1, wherein The thickness of the chemically strengthened glass is ≤2.0 mm; And / or, the surface compressive stress of the chemically strengthened glass is ≥650 MPa; And / or, the flexural strength of the chemically strengthened glass is ≥550 MPa; And / or, the transmittance attenuation of the chemically strengthened glass in a UV aging test (DH1000) is ≤1.5%; And / or, the light transmittance of the chemically strengthened glass is ≥91.5%; And / or, the chemically strengthened glass has a light transmittance of ≥94% and a flexural strength of ≥600 MPa after coating.

5. A method for preparing the chemically strengthened glass according to any one of claims 1 to 4, characterized in that: The following steps are involved: Weighing glass raw materials according to the composition of the chemically strengthened glass, melting the glass raw materials to obtain glass liquid, and forming and annealing the glass liquid to obtain a glass raw sheet; After polishing and cleaning the glass original sheet, it is immersed in molten salt to perform a first-stage ion exchange treatment to obtain the chemically strengthened glass.

6. The method for preparing chemically strengthened glass according to claim 5, wherein: In the annealing step, the annealing temperature is 600° C. to 700° C., and the annealing time is 2 h to 3 h; And / or, the acid resistance grade of the glass sheet is greater than or equal to grade 1; And / or, the moisture resistance grade of the glass sheet is above HGB2.

7. The method for preparing chemically strengthened glass according to claim 5, wherein: After the polishing process, the surface roughness of the glass sheet is Ra≤0.1 μm; And / or, in the step of the first-stage ion exchange, the temperature range of the first-stage ion exchange is 440° C. to 450° C., and the time of the first-stage ion exchange is 4 hours to 10 hours; And / or, the molten salt includes KNO3.

8. The method for preparing chemically strengthened glass according to any one of claims 5 to 7, characterized in that: After the first stage ion exchange treatment is completed, a pulse electric field is applied to the molten salt to carry out the second stage ion exchange treatment.

9. The method for preparing chemically strengthened glass according to claim 8, wherein: The voltage range of the pulse electric field is 100V to 150V; and / or the frequency range of the pulse electric field is 10Hz to 15Hz.

10. A photovoltaic module, characterized in that: The photovoltaic module comprises the chemically strengthened glass according to any one of claims 1 to 4.

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