Optical coating compositions, optical coatings, and photovoltaic modules comprising the same.

Abstract

This invention provides an optical coating composition, an optical coating, and a photovoltaic module comprising the same. The optical coating composition includes: component A: a cyclic sulfur compound having the structure shown in the formula; component B: a polythiol compound; and component C: a polyisocyanate compound. The optical coating composition described in this application, while meeting the requirements for heat resistance, color stability, and mechanical properties, can adjust the refractive index of the optical coating composition to between 1.49 and 1.80, solving the problem of low light utilization caused by mismatch between the encapsulation film and the solar cell in the prior art.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cells, and more specifically, to an optical coating composition, an optical coating, and a photovoltaic module comprising the same. Background Technology

[0002] In photovoltaic cells, sunlight passes through the upper tempered glass and the encapsulating film (EVA), where it is converted from light energy into electrical energy on the crystalline silicon wafer. Theoretical research shows that if the refractive index of the encapsulating material between the tempered glass and the solar cell is the geometric average of the materials on both sides, the reflectivity is 0, and the solar cell's utilization efficiency of sunlight reaches its maximum. Traditional solar module encapsulation materials have a lower refractive index than glass. This means that when sunlight passes through the glass and then through the EVA, the angle of refraction increases accordingly, leading to the following problems: the incident angle of light reaching the solar cell also increases, resulting in greater losses of reflected and diffused light. The refractive index of glass is 1.52, and the refractive index of silicon nitride, the passivation layer of the silicon solar cell, is 2.0. According to the formula, the required refractive index of the encapsulating film is 1.74. However, the refractive index of commonly used encapsulation materials is less than 1.5, far below the requirement, significantly affecting light utilization efficiency.

[0003] Currently, the main method for increasing the refractive index of encapsulating films is to add high-refractive-index inorganic nanomaterials to the matrix resin. However, directly adding high-refractive-index inorganic nanomaterials to the film can lead to phase separation due to the high surface energy of the nanoparticles and the mismatch between their polarity and the matrix film. This results in unstable film structure and prevents the nanomaterials from effectively increasing the film's refractive index, leading to a minimal overall improvement. Furthermore, synthesizing small nanoparticles that maintain transparency, have a small particle size, and are suitable for encapsulating films presents significant technical challenges, hindering industrial applications.

[0004] To address the aforementioned issue of nanomaterial agglomeration, existing technologies typically employ dispersants and silane coupling agents to improve the dispersibility of nanomaterials in the film. However, using dispersants to improve nanomaterial dispersibility requires coating the nanomaterial particles with large amounts of dispersant. The complexation of the dispersant with the nanomaterial can degrade or impair the performance of the nanoparticles to be developed. The effect of using silane coupling agents to improve nanoparticle dispersibility is also limited. On one hand, even with silane coupling agents, it is difficult to form complete Si-OM bonds between the nanoparticles and the film matrix, resulting in a weak coupling effect. On the other hand, silane coupling agents increase the amount of residual hydroxyl groups on the nanoparticle surface. Under the influence of these residual hydroxyl groups, the binding force between nanoparticles increases, leading to a tendency for agglomeration and making it more difficult to decompose into primary particles. Furthermore, the addition of silane coupling agents usually occurs in a secondary aggregation state; therefore, insufficient dispersion of nanoparticles in the organic composition can also cause reduced transparency.

[0005] In the prior art, patent CN113061397B discloses a method for improving the refractive index of an encapsulant film: a material with a high refractive index (1.49-1.80) (i.e., an organic high-refractive-index portion) is placed on the surface of the encapsulant film substrate. During photovoltaic module manufacturing, the side of the encapsulant film with the organic high-refractive-index portion faces the photovoltaic cell to better match the cell's refractive index, thus reducing the angle of refraction of incident light and minimizing light loss caused by reflected and diffused light, effectively improving light utilization. However, this method also has drawbacks. Due to the uneven surface of the encapsulant film and its relatively soft material, the organic high-refractive-index material is not easily spread evenly on the film, and its thickness is difficult to control, making molding and processing challenging.

[0006] In summary, while theoretically high-refractive-index encapsulating films can be obtained by combining nanoscale high-refractive-index inorganic oxide particles with polymers, the refractive index of the encapsulating film is difficult to increase, and may even tend to decrease, due to the problem of nanoparticle aggregation. Furthermore, although setting an organic high-refractive-index layer on the substrate film can improve light utilization, it presents challenges in controlling the molding and processing.

[0007] In view of the above, there is an urgent need to provide an optical material with a high refractive index to improve the overall efficiency of photovoltaic modules. Summary of the Invention

[0008] The main objective of this invention is to provide an optical coating composition, an optical coating, and a photovoltaic module containing the same, in order to solve the problem that the low refractive index of the encapsulating film in photovoltaic modules in the prior art leads to low light utilization of the photovoltaic modules.

[0009] To achieve the above objectives, according to one aspect of the present invention, an optical coating composition is provided, comprising: Component A: a cyclic sulfur compound having the structure shown in formula (1);

[0010]

[0011] Wherein, X1 and X2 each independently represent -O- or -S-, and at least one of X1 and X2 is -S-; n takes 0 or 1; R represents a direct bond, -O-, -S-, substituted or unsubstituted C1-C50 straight-chain or branched alkylene group, substituted or unsubstituted C3-C60 cycloalkylene group, substituted or unsubstituted C1-C60 alkylene ether group, or substituted or unsubstituted C1-C50 alkylene thioether group;

[0012] Component B: Polythiol compounds; and

[0013] Component C: Polyisocyanate compounds.

[0014] Further, n is 1, and R represents a substituted or unsubstituted C1-C10 straight-chain or branched alkylene group, a substituted or unsubstituted C3-C12 cycloalkylene group, a substituted or unsubstituted C1-C10 alkylene ether group, or a substituted or unsubstituted C1-C10 alkylene thioether group.

[0015] Furthermore, component A is a cyclic sulfur compound having the structure shown in formula (2), where 1≤p+q≤4;

[0016]

[0017] Alternatively, component A is a cyclosulfide compound having the structure shown in formula (3); Y is a direct bond, -O-, -S- or -CH2-; M is a C1 to C3 alkyl group, and the hydrogen atom on the alkyl group may optionally be replaced by a 1,3-dithiopentane group;

[0018]

[0019] Furthermore, the cyclic sulfur compounds represented by formula (1) are selected from the following compounds:

[0020]

[0021] One or more of them.

[0022] Furthermore, the cyclic sulfur compounds represented by formula (1) are selected from the following compounds:

[0023]

[0024] One or more of them.

[0025] Further, by weight percentage, the optical coating composition comprises 40 to 99.995 wt% of component A, 0.001 to 30 wt% of component B, and 0.001 to 30 wt% of component C.

[0026] Further, by weight percentage, the optical coating composition comprises 50 to 99.995 wt% of component A, 0.003 to 20 wt% of component B, and 0.002 to 25 wt% of component C.

[0027] Further, by weight percentage, the optical coating composition comprises 60 to 99.990 wt% of component A, 0.05 to 15 wt% of component B, and 0.005 to 20 wt% of component C.

[0028] Furthermore, the polythiol compound is selected from 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (thioalkylmethyldithioalkyl)methanethiol, bis(2-mercaptoethyl) sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiaane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto- One or more of the following: 3,6,9-trithiaundecane, 1,3-bis(mercaptomethyl)benzene, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, 1,1,3,3-tetra(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene-pentaerythritol mercaptopropionate, 1,4-bis(mercaptomethyl)benzene, or thiacyclopropanemethanethiol.

[0029] Furthermore, the polythiol compound is selected from one or more of bis(2-mercaptoethyl) sulfide, 1,2,6,7-tetramercapto-4-thiaheptane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, pentaerythritol ester of 1,3-bis(mercaptomethyl)phenyl mercaptopropionate, 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, or 1,3-bis(mercaptomethyl)benzene.

[0030] Furthermore, the polyisocyanate compound is selected from diethylidene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, isophorone diisocyanate, 2,6-bis(isocyanate methyl)decahydronaphthalene, lysine triisocyanate, toluene diisocyanate, o-toluidine diisocyanate, diphenylmethane diisocyanate, diphenyl ether diisocyanate, 3-(2'- 2,2'-Bis(cyclohexyl)isocyanate, isopropylidene bis(cyclohexyl)isocyanate, 2,2'-bis(4-isocyanate phenyl)propane, triphenylmethane triisocyanate, bis(diisocyanate tolyl)phenylmethane, 4,4',4”-triisocyanate-2,5-dimethoxyphenylamine, 3,3'-dimethoxybenzidine-4,4'-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diisocyanate biphenyl, 4,4'-diisocyanate-3,3'-dimethyl Biphenyl, dicyclohexylmethane-4,4'-diisocyanate, 1,1'-methylenebis(4-isocyanate benzene), 1,1'-methylenebis(3-methyl-4-isocyanate benzene), m-phthalimide diisocyanate, p-phthalimide diisocyanate, m-tetramethylphthalimide diisocyanate, p-tetramethylphthalimide diisocyanate, 1,3-bis(2-isocyanate-2-propyl)benzene, 2,6-bis(isocyanate methyl)naphthalene, 1,5-naphthalene diisocyanate, bis(isocyanate methyl)tetrahydrodicyclopentadiene, bis(isocyanate) One or more of the following: (methyl)dicyclopentadiene, bis(methyl)tetrahydrothiophene, bis(methyl)norbornene, bis(methyl)adamantane, thiodiethyl diisocyanate, thiodipropyl diisocyanate, thiodihexyl diisocyanate, bis[(4-methyl)phenyl]sulfide, 2,5-diisocyanate-1,4-dithiane, 2,5-diisocyanate-methyl-1,4-dithiane, 2,5-diisocyanate-methylthiophene, dithiodiethyl diisocyanate, or dithiodipropyl diisocyanate.

[0031] Furthermore, the polyisocyanate compound is selected from one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, m-phenylene diisocyanate, terephthalene diisocyanate, m-tetramethylphenylene diisocyanate, terephthalene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, bis(isocyanate methyl)norbornene, and 2,5-diisocyanate methyl-1,4-dithiane.

[0032] Furthermore, the polyisocyanate compound is selected from one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane or isophthalene diisocyanate.

[0033] Furthermore, the polyisocyanate compound is selected from one or more of isophorone diisocyanate, isophthalene diisocyanate, hexamethylene diisocyanate, or 1,3-bis(isocyanate methyl)cyclohexane.

[0034] Furthermore, the optical coating composition also includes component D: a curing agent.

[0035] Furthermore, the curing agent is selected from one or more of amine curing agents, phosphine curing agents, or onium salt curing agents.

[0036] Furthermore, the curing agent is selected from onium salt curing agents; the onium salt curing agent is selected from one or more of quaternary ammonium salt curing agents, quaternary phosphonium salt curing agents, tertiary sulfonium salt curing agents or secondary iodomonium salt curing agents.

[0037] Furthermore, the onium salt curing agent is selected from quaternary ammonium salt curing agents and / or quaternary phosphonium salt curing agents.

[0038] Furthermore, the quaternary ammonium salt curing agent is selected from one or more of tetra-n-butylammonium bromide, triethylbenzylammonium chloride, hexadecyl dimethylbenzylammonium chloride, or 1-n-dodecylpyridinium chloride; the quaternary phosphonium salt curing agent is selected from one or more of tetra-n-butylammonium bromide, triethylbenzylammonium chloride, or tetra-n-butylphosphonium bromide.

[0039] Furthermore, in the optical coating composition, the curing agent has a weight content of 0.0001 to 10 wt%; more preferably 0.001 to 5 wt%; and even more preferably 0.01 to 1 wt%.

[0040] Furthermore, the optical coating composition also includes component E: additives.

[0041] Furthermore, the additives are selected from one or more of antioxidants, ultraviolet absorbers, light stabilizers, or thickeners.

[0042] Furthermore, the antioxidant is selected from hindered phenolic compounds and / or phosphite compounds.

[0043] Furthermore, the hindered phenolic compounds are selected from 2,6-di-tert-butyl-4-ethylphenol, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol), 4,4'-butylene-bis-(3-methyl-6-tert-butylphenol), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 7-octadecyl-3-(4'-hydroxy-3', One or more of 5'-di-tert-butylphenyl)propionate or tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane; the phosphite compound is selected from one or more of tris(2,4-di-tert-butylphenyl)phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl phosphite, tetra(2,4-di-tert-butylphenyl)[1,1-phenyl]-4,4'-diyl bisphosphite or bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

[0044] Furthermore, the ultraviolet absorber is selected from benzophenone compounds and / or benzotriazole compounds; the benzophenone compound is selected from one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2,2-tetramethylenebis(3,1-benzoxazin-4-one) or 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; the benzotriazole compound is selected from 2-(2'-hydroxy-5-methylphenyl)benzotriazole.

[0045] Furthermore, the light stabilizer is a hindered amine compound; the hindered amine compound is selected from one or more of the following: bis(2,2,6,6-tetramethyl-4-piperidinyl)selpicate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl)selpicate, graft copolymer obtained by polymerization of 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine with α-ene monomers, 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, bis-2,2,6,6-tetramethylpiperidinol sebacic acid, or tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite.

[0046] Furthermore, the tackifier is selected from one or more of γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethylsilane, or 3-aminopropyltrimethylsilane.

[0047] Furthermore, in the optical coating composition, the weight content of the additives is 0.01–5 wt%.

[0048] To achieve the above objectives, according to one aspect of the present invention, an optical coating is provided, which is obtained by curing the optical coating composition described above according to the present invention.

[0049] Furthermore, the curing time is 0.01 to 2 hours.

[0050] Furthermore, the curing temperature is 10–180°C, more preferably 80–150°C.

[0051] According to another aspect of the present invention, a photovoltaic module is provided, comprising a cell, wherein the optical coating described above is disposed on the outer surface of the cell.

[0052] Applying the technical solution of this invention, the optical coating composition of this invention includes a cyclic sulfur compound having the structure of formula (1), wherein X1 and X2 each independently represent -O- or -S-, and at least one of X1 and X2 is -S-. Through the synergistic effect of X1 and X2, the resulting cyclic sulfur compound has a high refractive index and suitable monomer activity. Furthermore, by combining different structures of R, the monomer structure has different viscosities, facilitating processing and enabling the optical coating composition to obtain a superior refractive index and better processing conditions. Secondly, the optical coating composition of this invention also includes a polythiol compound and a polyisocyanate compound. By adding the polythiol compound and the polyisocyanate compound, a synergistic effect can be achieved between them and the cyclic sulfur compound having the structure of formula (1), satisfying a high curing rate while also possessing superior transparency. The polythiol compound can improve the color tone effect of the optical coating composition when heated. The isocyanate group of the polyisocyanate compound and the thiol group of the polythiol compound can easily undergo a thermosetting reaction to increase the molecular weight, thereby improving the mechanical strength of the optical coating obtained through subsequent processing. In summary, by synergistically combining the cyclic sulfur compound, polythiol compound, and polyisocyanate compound with the structure shown in formula (1), the refractive index of the optical coating composition can be adjusted to between 1.49 and 1.80 while meeting the requirements for heat resistance, color stability, and mechanical properties. This solves the problem of low light utilization caused by the mismatch between the encapsulation film and the battery cell in the prior art. Detailed Implementation

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0054] As described in the background section of this application, the encapsulating film of photovoltaic modules in the prior art has a low refractive index, resulting in low light utilization of the photovoltaic modules. In order to solve this problem, this application provides an optical coating composition comprising: component A: a cyclic sulfur compound having the structure shown in formula (1); component B: a polythiol compound; and component C: a polyisocyanate compound.

[0055]

[0056] Where X1 and X2 each independently represent -O- or -S-, and at least one of X1 and X2 is -S-; n takes 0 or 1; R represents a direct bond, -O-, -S-, substituted or unsubstituted C1-C50 straight-chain or branched alkylene group, substituted or unsubstituted C3-C60 cycloalkylene group, substituted or unsubstituted C1-C60 alkylene ether group, or substituted or unsubstituted C1-C50 alkylene thioether group.

[0057] First, the optical coating composition of the present invention includes a cyclic sulfur compound having the structure of formula (1), wherein X1 and X2 each independently represent -O- or -S-, and at least one of X1 and X2 is -S-. Through the synergistic effect of X1 and X2, the resulting cyclic sulfur compound has a high refractive index and suitable monomer activity. Furthermore, by combining different structures of R, the monomer structure has different viscosities, facilitating processing and enabling the optical coating composition to achieve a superior refractive index and better processing conditions. Second, the optical coating composition of the present invention also includes a polythiol compound and a polyisocyanate compound. By adding the polythiol compound and the polyisocyanate compound, a synergistic effect can be achieved with the cyclic sulfur compound having the structure of formula (1), satisfying a high curing rate while also possessing superior transparency. The polythiol compound can improve the color tone effect of the optical coating composition when heated. The isocyanate group of the polyisocyanate compound and the thiol group of the polythiol compound can easily undergo a thermosetting reaction to increase the molecular weight, thereby improving the mechanical strength of the optical coating obtained through subsequent processing. In summary, by synergistically combining the cyclic sulfur compound, polythiol compound, and polyisocyanate compound with the structure shown in formula (1), the refractive index of the optical coating composition can be adjusted to between 1.49 and 1.80 while meeting the requirements for heat resistance, color stability, and mechanical properties. This solves the problem of low light utilization caused by the mismatch between the encapsulation film and the battery cell in the prior art.

[0058] To further improve the refractive index of the optical coating composition, preferably, n is 1, and R represents substituted or unsubstituted C1-C10 straight-chain or branched alkylene groups (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, n-hexyl, n-octyl, isobutyl, tert-butyl, etc.), substituted or unsubstituted C3-C12 cycloalkylene groups (e.g., cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, etc.), substituted or unsubstituted C1-C10 alkylene ether groups (e.g., cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, etc.), and substituted or unsubstituted C1-C10 alkyl sulfide groups (e.g., alkyl sulfide groups contain at least one carbon-sulfur bond, but may include more than one carbon-sulfur bond, such as ethylene disulfide, diethylene disulfide, propylene disulfide, etc.).

[0059] To further improve the refractive index of the optical coating composition, preferably, component A is a cyclic sulfide compound having the structure shown in formula (2), where 1≤p+q≤4;

[0060]

[0061] Alternatively, component A is a cyclosulfide compound having the structure shown in formula (3); Y is a direct bond, -O-, -S- or -CH2-; M is a C1 to C3 alkyl group, and the hydrogen atom on the alkyl group may optionally be replaced by a 1,3-dithiopentane group;

[0062]

[0063] More preferably, the cyclic sulfur compound represented by formula (1) is selected from the following compounds:

[0064]

[0065]

[0066] One or more of them.

[0067] When using the above-described cyclic sulfide compound, compared to cyclic sulfide compounds where R is selected as a substituted or unsubstituted C1-C50 straight-chain or branched alkylene group, the cyclic sulfide compound with the above structure has a higher refractive index, better resistance to yellowing, and higher light transmittance. Therefore, it can achieve better light utilization when used as a raw material for optical coatings. When using straight-chain cyclic sulfide compounds, these compounds have a stronger odor and a darker color at room temperature, affecting the light transmittance of optical materials. Furthermore, straight-chain cyclic sulfide compounds have poor anti-aging properties and are prone to yellowing. Consequently, when used as a raw material for optical coatings, the poor light transmittance and susceptibility to yellowing lead to a decrease in the light utilization of the material.

[0068] More preferably, the cyclic sulfur compound represented by formula (1) is selected from the following compounds:

[0069]

[0070] One or more of them.

[0071] To obtain an optical coating composition with superior overall performance, the optical coating composition preferably comprises, by weight percentage, 40–99.995 wt% of component A, 0.001–30 wt% of component B, and 0.001–30 wt% of component C. Excessive use of component A will lead to a decrease in the curing rate of the optical coating composition, while insufficient use will result in lower optical properties (e.g., refractive index) of the product. Excessive use of component C will reduce the hue, while insufficient use will fail to meet strength requirements. Excessive use of component B will cause the curing rate to be too fast during the preparation of the optical coating composition, resulting in opacity and affecting the optical utilization efficiency of the product; insufficient use will result in incomplete curing during the preparation of the optical coating composition. By synergistically combining components A, B, and C in a specific ratio, the refractive index of the optical coating composition can be adjusted to between 1.49 and 1.80 while meeting the requirements for heat resistance, hue stability, and mechanical properties, thus solving the problem of low light utilization caused by mismatch between the encapsulation film and the battery cell in the prior art.

[0072] To further improve the refractive index of the optical coating composition, more preferably, the optical coating composition comprises 50–99.995 wt% of component A, 0.003–20 wt% of component B, and 0.002–25 wt% of component C. More preferably, the optical coating composition comprises 60–99.990 wt% of component A, 0.05–15 wt% of component B, and 0.005–20 wt% of component C. Even more preferably, the optical coating composition comprises 60–99.990 wt% of component A, 0.05–12 wt% of component B, and 0.005–20 wt% of component C.

[0073] To further improve the tonal effect of the optical coating composition and to better synergize with polyisocyanate compounds, thereby enhancing the mechanical properties of the optical coating composition during subsequent processing to form an optical coating, the polythiol compounds are selected from 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (thioalkylmethyldithioalkyl)methanethiol, bis(2-mercaptoethyl) sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiaane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,7-dimercaptomethyl-1,11-dimercapto-3,6 One or more of the following: 9-trithiaundecane, 1,3-bis(mercaptomethyl)benzene, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, 1,1,3,3-tetra(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene-pentaerythritol mercaptopropionate, 1,4-bis(mercaptomethyl)benzene, or thiacyclopropanemethanethiol.

[0074] Preferably, the polythiol compound is selected from one or more of bis(2-mercaptoethyl) sulfide, 1,2,6,7-tetramercapto-4-thiaheptane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, pentaerythritol ester of 1,3-bis(mercaptomethyl)phenyl mercaptopropionate, 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, or 1,3-bis(mercaptomethyl)benzene.

[0075] To further improve the mechanical strength of the optical coating obtained from subsequent processing of the optical coating composition, the polyisocyanate compound is selected from diethylidene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, isophorone diisocyanate, 2,6-bis(isocyanate methyl)decahydronaphthalene, lysine triisocyanate, toluene diisocyanate, o-toluidine diisocyanate, and diphenylmethane diisocyanate. Cyanide esters, diphenyl ether diisocyanate, 3-(2'-cyclohexyl isocyanate)propyl isocyanate, isopropylidene bis(cyclohexyl isocyanate), 2,2'-bis(4-phenyl isocyanate)propane, triphenylmethane triisocyanate, bis(tolyl diisocyanate)phenylmethane, 4,4',4”-triisocyanate-2,5-dimethoxyphenylamine, 3,3'-dimethoxybenzidine-4,4'-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diisocyanate biphenyl, 4,4'- Diisocyanate-3,3'-dimethylbiphenyl, dicyclohexylmethane-4,4'-diisocyanate, 1,1'-methylenebis(4-isocyanate benzene), 1,1'-methylenebis(3-methyl-4-isocyanate benzene), isophthalene diisocyanate, p-phthalene diisocyanate, m-tetramethylphenyl diisocyanate, p-tetramethylphenyl diisocyanate, 1,3-bis(2-isocyanate-2-propyl)benzene, 2,6-bis(isocyanate methyl)naphthalene, 1,5-naphthalene diisocyanate, bis(isocyanate methyl)tetrahydrodicyclopentadiene One or more of the following: bis(methyl)dicyclopentadiene, bis(methyl)tetrahydrothiophene, bis(methyl)norbornene, bis(methyl)adamantane, thiodiethyl diisocyanate, thiodipropyl diisocyanate, thiodihexyl diisocyanate, bis[(4-methyl)phenyl]sulfide, 2,5-diisocyanate-1,4-dithiane, 2,5-diisocyanate-methyl-1,4-dithiane, 2,5-diisocyanate-methylthiophene, dithiodiethyl diisocyanate, or dithiodipropyl diisocyanate.

[0076] Preferably, the polyisocyanate compound is selected from one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, m-phenylene diisocyanate, terephthalene diisocyanate, m-tetramethylphenylene diisocyanate, terephthalene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, bis(isocyanate methyl)norbornene, or 2,5-diisocyanate methyl-1,4-dithiane.

[0077] More preferably, the polyisocyanate compound is selected from one or more of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane or isophthalene diisocyanate.

[0078] More preferably, the polyisocyanate compound is selected from one or more of isophorone diisocyanate, isophthalene diisocyanate, hexamethylene diisocyanate, or 1,3-bis(isocyanate methyl)cyclohexane. The present invention prefers the above-mentioned polyisocyanate compound based on the following considerations: Since the above-mentioned polyisocyanate compound has no conjugated bonds in its molecular structure and contains a larger benzene ring or cyclohexane in its molecule, it is easier to prepare optical materials with high refractive index, high heat resistance, and low dispersion.

[0079] To further balance the tone stability and heat resistance of the optical coating composition, the ratio of the total number of SH groups in the polythiol compounds to the number of NCO groups in the polyisocyanate compounds is preferably 1.0 to 2.5. When the ratio of the total number of SH groups in the thiol compounds to the number of NCO groups in the polyisocyanate compounds is higher than 2.5, the heat resistance of the optical coating composition will be reduced. When the ratio of the total number of SH groups in the thiol compounds to the number of NCO groups in the polyisocyanate compounds is lower than 1.0, the curing rate of the optical coating composition will be low, making film formation difficult and resulting in failure to form a film.

[0080] In a preferred embodiment, the optical coating composition further includes component D: a curing agent. The addition of a curing agent to the optical coating composition of the present invention enables the composition components to polymerize and cure to obtain an optical coating material, thereby improving the heat resistance and mechanical properties of the optical coating material.

[0081] To further improve the curing effect, the curing agent is preferably selected from one or more of amine curing agents, phosphine curing agents, or onium salt curing agents; more preferably, the curing agent is selected from onium salt curing agents; the onium salt curing agent is selected from one or more of quaternary ammonium salt curing agents, quaternary phosphonium salt curing agents, tertiary sulfonium salt curing agents, or secondary iodomonium salt curing agents; even more preferably, the curing agent is selected from quaternary ammonium salt curing agents and / or quaternary phosphonium salt curing agents. Using the above-mentioned curing agents can further improve the compatibility of the composition in the optical coating composition, and even more preferably, it is a quaternary phosphonium salt curing agent.

[0082] Specifically, the quaternary ammonium salt curing agent can be selected from quaternary ammonium salts such as tetra-n-butylammonium bromide, triethylbenzylammonium chloride, hexadecyl dimethylbenzylammonium chloride, and 1-n-dodecylpyridinium chloride; the quaternary phosphonium salt curing agent can be selected from quaternary phosphonium salts such as tetra-n-butylphosphonium bromide and tetraphenylphosphonium bromide. More preferably, tetra-n-butylammonium bromide, triethylbenzylammonium chloride, and tetra-n-butylphosphonium bromide are selected.

[0083] In some alternative embodiments, the amount of curing agent may vary depending on the composition, dosage ratio, and curing method. In a preferred embodiment, the weight content of the curing agent in the optical coating composition is 0.0001–10 wt%. The present invention limits the curing agent to the above range based on the following considerations: when the amount of curing agent is too high, it will cause rapid polymerization between the optical coating compositions, resulting in uneven curing and a decrease in the mechanical strength of the optical coating material; when the amount of curing agent is too low, the optical coating compositions cannot be fully cured, and the heat resistance will deteriorate. More preferably, it is 0.001–5 wt%; even more preferably, it is 0.01–1 wt%; and even more preferably, it is 0.01–0.5 wt%.

[0084] To further improve the practicality of the resulting optical coating composition, the optical coating composition also includes component E: an additive. Preferably, the additive is selected from one or more of antioxidants, ultraviolet absorbers, light stabilizers, or tackifiers.

[0085] To achieve better stability and antioxidant properties while maintaining a high refractive index, the antioxidant is preferably a hindered phenolic compound and / or a phosphite compound. More preferably, the hindered phenolic compound is selected from one or more of 2,6-di-tert-butyl-4-ethylphenol, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol), 4,4'-butylene-bis-(3-methyl-6-tert-butylphenol), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 7-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate or tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane. This invention improves the processing performance and long-term stability of optical coating compositions by adding antioxidants, thereby delaying degradation caused by heat and oxygen.

[0086] In a preferred embodiment, the ultraviolet absorber includes, but is not limited to, benzophenone compounds and / or benzotriazole compounds. Specifically, the benzophenone compounds are selected from one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2,2-tetramethylenebis(3,1-benzoxazin-4-one), or 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; the benzotriazole compounds are selected from 2-(2'-hydroxy-5-methylphenyl)benzotriazole. Under the premise of satisfying a high refractive index, the addition of an ultraviolet absorber to the optical coating composition of the present invention can absorb most of the ultraviolet energy and convert it into heat, thereby protecting electronic devices from damage by ultraviolet radiation.

[0087] In a preferred embodiment, the light stabilizer is a hindered amine compound; specifically, the hindered amine compound is selected from one or more of the following: bis(2,2,6,6-tetramethyl-4-piperidinyl)selpicate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl)selpicate, a graft copolymer obtained by polymerizing 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine with an α-ene monomer, 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, bis-2,2,6,6-tetramethylpiperidinol sebacic acid, or tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite. Under the premise of satisfying a high refractive index, the addition of a light stabilizer to the optical coating composition in this invention can improve the stability of the optical coating material under long-term ultraviolet irradiation.

[0088] In a preferred embodiment, the tackifier is selected from one or more of γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethylsilane, or 3-aminopropyltrimethylsilane. Under the premise of satisfying a high refractive index, the addition of a tackifier to the optical coating composition of the present invention can improve the adhesion between the optical coating material and the battery cell.

[0089] To obtain an optical coating composition with superior overall performance, the additives are preferably present in a weight content of 0.01 to 5 wt%.

[0090] The present invention also provides an optical coating, which is obtained by curing the above-described optical coating composition.

[0091] Based on the reasons mentioned above, the optical coating of the present invention has superior refractive index, heat resistance, mechanical strength, and color tone.

[0092] In some optional embodiments, components A, B, C, D, and E are mixed using ultrasonic and / or mechanical methods for 0.1–1 hour, followed by curing. To further improve the curing effect, the curing time is 0.01–2 hours; preferably, the curing temperature is 10–180°C, more preferably 80–150°C.

[0093] In a preferred embodiment, the curing process comprises three stages: the first stage is a heating stage, in which the material is heated from room temperature (18–25°C) to the curing temperature at a heating rate of 0.1–100°C / min. The second stage is a holding stage, in which the material is held at the curing temperature for 0.1–5 hours. The third stage is a cooling stage, in which the material is cooled from the curing temperature to room temperature (18–25°C) at a cooling rate of 0.1–100°C / min, thus completing the curing process.

[0094] The present invention also provides a photovoltaic module, including a cell, wherein the above-mentioned optical coating is disposed on the outer surface of the cell.

[0095] Based on the reasons mentioned above, the optical coating of the present invention not only has high refractive index and stable structure, which can effectively reduce light loss caused by reflected and diffuse reflection light and effectively improve the light utilization rate of photovoltaic modules, but also has the advantages of simple preparation process and low cost.

[0096] In some alternative embodiments, the present invention can apply an optical coating to the battery cell using common processing methods such as coating, inkjet printing, or spraying.

[0097] To further balance the light utilization rate and production cost of photovoltaic modules, the thickness of the optical coating is preferably 1 to 100 μm.

[0098] To obtain photovoltaic modules with superior overall performance, photovoltaic modules include a glass cover, a front encapsulation film, an optical coating, solar cell units, an optical coating, a back encapsulation film, and a back cover.

[0099] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0100] Example

[0101] Optical coating composition:

[0102] (A) Cyclic sulfur compounds: (A1)

[0103] (A2) (A3)

[0104] (B) Polythiol compounds: (B1) 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol (commercial manufacturer: Yifeng New Materials), (B2) pentaerythritol ester of 1,3-bis(mercaptomethyl)phenylmercaptopropionate (commercial manufacturer: Yifeng New Materials), (B3) 1,2,6,7-tetramercapto-4-thiaheptane (commercial manufacturer: Aladdin).

[0105] (C) Polyisocyanate compounds: (C1) Isophorone diisocyanate (commercial manufacturer: Aladdin), (C2) Hexamethylene diisocyanate (commercial manufacturer: Wanhua Chemical), (C3) 1,3-bis(isocyanate methyl)cyclohexane (commercial manufacturer: McLean).

[0106] (D) Catalysts: (D1) hexadecyl dimethyl benzyl ammonium chloride (commercial manufacturer: Maclean), (D2) tetra-n-butylphosphonium bromide (commercial manufacturer: Maclean).

[0107] (E) Antioxidant: Pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0108] (F) Ultraviolet absorber: 2-hydroxy-4-n-octyloxybenzophenone.

[0109] (G) Light stabilizer: hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate.

[0110] The above-mentioned (A) cyclic sulfur compound, (B) polythiol compound, (C) polyisocyanate compound, (D) curing agent, and optional (E) antioxidant, optional (F) UV absorber, and optional (G) light stabilizer are ultrasonically mixed for 0.5 hours at the contents listed in Table 1 (unit: wt%), and then cured (curing temperature: 90℃, curing time: 0.5h) to obtain an optical coating. The optical coating is transferred onto a solar cell by coating method to form a solar cell with an optical coating of 10-50μm. The solar cell with the above-obtained optical coating, EVA resin film (VA content: 28wt%, commercially available from DuPont, USA), and cover glass are laminated to form a photovoltaic module.

[0111] Comparative Example 1

[0112] The only difference from the embodiment is that the photovoltaic module does not have an optical coating on the solar cells, and the encapsulant EVA resin (VA content of 28wt%, DuPont, USA), solar cells and cover glass are directly laminated into a photovoltaic module.

[0113] Comparative Example 2

[0114] The only difference from the examples is that the optical coating composition does not include (A) cyclic sulfur compounds.

[0115] Comparative Example 3

[0116] The only difference from the example is that the (Aa) cyclic sulfur compound in the optical coating composition is: bis(β-cyclothiopropyl) sulfide (Shanghai Xinkai Pharmaceutical Technology Co., Ltd.), bis(β-cyclothiopropyl) disulfide (commercially available from Aladdin), and 1,4-bis(β-cyclothiopropylthio)butane (commercially available from Mitsubishi Chemical). The weight ratio of bis(β-cyclothiopropyl) sulfide:bis(β-cyclothiopropyl) disulfide:1,4-bis(β-cyclothiopropylthio)butane is 1:1:1.

[0117] Performance testing methods

[0118] 1. Refractive index

[0119] The refractive index of the optical coatings obtained in the examples and comparative examples was measured using an Abbe refractometer.

[0120] 2. Light transmittance

[0121] The transmittance of the optical coatings in the above embodiments and comparative examples was tested according to GB / T2410-2008. The transmittance of the optical coatings at wavelengths of 400 to 780 nm was measured using a UV-Vis spectrophotometer.

[0122] 3. Yellowing test

[0123] The optical coatings from the above embodiments and comparative examples were placed in a UV aging test chamber and subjected to UV irradiation of 120 kWh / m². 2 Samples were taken afterward. Before and after the experiment, the yellow index of the samples was tested according to ASTM E313-2010. At least 3 points were measured for each sample, and the average value was taken. The difference in yellow index before and after the UV accelerated aging test was taken as the yellowing index △YI.

[0124] 4. Component power test:

[0125] The photovoltaic modules prepared above will be used in a 1000W / m 2 Power was measured using a Quicksun 820A power simulator at nominal irradiance and an ambient temperature of 30°C. The performance results of the optical coating material are shown in Table 1 below.

[0126] Table 1

[0127]

[0128] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: The present application provides a material with a high refractive index (1.49-1.8) (i.e., a high refractive index optical coating) on ​​the surface of the solar cell. During the fabrication of photovoltaic modules, this better matches the refractive indices of the solar cell and the encapsulant film, reducing the angle of refraction of incident light and minimizing light loss caused by reflected and diffused light, thus effectively improving light utilization. Furthermore, because the coating structure of the present application is more stable, it avoids the problem in the prior art where the refractive index cannot be effectively improved due to the agglomeration of encapsulant film additives. Moreover, the coating material of the present application is simple to process, providing a low-cost method for improving solar cell efficiency.

[0129] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical coating composition characterized in that, The optical coating composition comprises: Component A: A cyclic sulfur compound having the structure shown in formula (2) or formula (3); When component A is a cyclic sulfur compound having the structure shown in formula (2), 1≤p+q≤4; Equation (2); When component A is a cyclic sulfur compound having the structure shown in formula (3), Y is -O- or -S-; M is a C1~C3 alkyl group, and the hydrogen atom on the alkyl group is optionally replaced by a 1,3-dithiopentane group; Equation (3); Wherein, X1 and X2 independently represent -O- or -S-, and at least one of X1 and X2 is -S-; n is 1; Component B: Polythiol compounds; and Component C: Polyisocyanate compounds.

2. The optical coating composition according to claim 1, characterized in that, The cyclic sulfur compound is selected from the following compounds: 、 、 、 、 、 、 , , , or One or more of them.

3. The optical coating composition according to claim 2, characterized in that, The cyclic sulfur compound is selected from the following compounds: , , , , or One or more of them.

4. The optical coating composition according to claim 1, characterized in that, The optical coating composition comprises, by weight percentage, 40-99.995 wt% of component A, 0.001-30 wt% of component B, and 0.001-30 wt% of component C.

5. The optical coating composition according to claim 4, characterized in that, The optical coating composition comprises, by weight percentage, 50-99.995 wt% of component A, 0.003-20 wt% of component B, and 0.002-25 wt% of component C.

6. The optical coating composition according to claim 5, characterized in that, The optical coating composition comprises, by weight percentage, 60-99.990 wt% of component A, 0.05-15 wt% of component B, and 0.005-20 wt% of component C.

7. The optical coating composition according to any one of claims 1 to 4, characterized in that, The polythiol compound is selected from 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (thioalkylmethyldithioalkyl)methanethiol, bis(2-mercaptoethyl) sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiaane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3, One or more of the following: 6,9-trithiaundecane, 1,3-bis(mercaptomethyl)benzene, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, 1,1,3,3-tetra(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene-pentaerythritol mercaptopropionate, 1,4-bis(mercaptomethyl)benzene, or thiacyclopropanemethanethiol.

8. The optical coating composition according to claim 7, characterized in that, The polythiol compound is selected from one or more of the following: bis(2-mercaptoethyl) sulfide, 1,2,6,7-tetramercapto-4-thiaheptane, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, pentaerythritol ester of 1,3-bis(mercaptomethyl)benzene mercaptopropionate, 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol, or 1,3-bis(mercaptomethyl)benzene.

9. The optical coating composition according to any one of claims 1 to 4, characterized in that, The polyisocyanate compound is selected from diethylidene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, isophorone diisocyanate, 2,6-bis(isocyanate methyl)decahydronaphthalene, lysine triisocyanate, toluene diisocyanate, o-toluidine diisocyanate, diphenylmethane diisocyanate, diphenyl ether diisocyanate, 3-(2'-isocyanate) 2,2'-bis(cyclohexyl)propyl isocyanate, isopropylidene bis(cyclohexyl)isocyanate, 2,2'-bis(4-isocyanate phenyl)propane, triphenylmethane triisocyanate, bis(diisocyanate tolyl)phenylmethane, 4,4',4”-triisocyanate-2,5-dimethoxyphenylamine, 3,3'-dimethoxybenzidine-4,4'-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diisocyanate biphenyl, 4,4'-diisocyanate-3,3'-dimethylbenzidine Benzene, dicyclohexylmethane-4,4'-diisocyanate, 1,1'-methylenebis(4-isocyanate benzene), 1,1'-methylenebis(3-methyl-4-isocyanate benzene), m-phenylene diisocyanate, p-phenylene diisocyanate, m-tetramethylphenylene diisocyanate, p-tetramethylphenylene diisocyanate, 1,3-bis(2-isocyanate-2-propyl)benzene, 2,6-bis(isocyanate methyl)naphthalene, 1,5-naphthalene diisocyanate, bis(isocyanate methyl)tetrahydrodicyclopentadiene, bis(isocyanate methyl) The following are some of the following: dicyclopentadiene, bis(methyl)tetrahydrothiophene, bis(methyl)norbornene, bis(methyl)adamantane, dithiodiethyl diisocyanate, dithiodipropyl diisocyanate, dithiodihexyl diisocyanate, bis[(4-methyl)phenyl]sulfide, 2,5-diisocyanate-1,4-dithiane, 2,5-diisocyanate-methyl-1,4-dithiane, 2,5-diisocyanate-methylthiophene, dithiodiethyl diisocyanate, or dithiodipropyl diisocyanate.

10. The optical coating composition according to claim 9, characterized in that, The polyisocyanate compound is selected from one or more of the following: isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, m-tetramethylphenylene diisocyanate, p-tetramethylphenylene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, bis(isocyanate methyl)norbornene, and 2,5-diisocyanate methyl-1,4-dithiane.

11. The optical coating composition according to claim 10, characterized in that, The polyisocyanate compound is selected from one or more of the following: isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, or isophthalene diisocyanate.

12. The optical coating composition according to claim 11, characterized in that, The polyisocyanate compound is selected from one or more of the isophorone diisocyanate, isophthalene diisocyanate, hexamethylene diisocyanate, or 1,3-bis(isocyanate methyl)cyclohexane.

13. The optical coating composition according to any one of claims 1 to 4, characterized in that, The optical coating composition also includes component D: a curing agent.

14. The optical coating composition according to claim 13, characterized in that, The curing agent is selected from one or more of amine curing agents, phosphine curing agents, or onium salt curing agents.

15. The optical coating composition according to claim 14, characterized in that, The curing agent is selected from the onium salt curing agent; the onium salt curing agent is selected from one or more of quaternary ammonium salt curing agents, quaternary phosphonium salt curing agents, tertiary sulfonium salt curing agents or secondary iodomonium salt curing agents.

16. The optical coating composition according to claim 15, characterized in that, The onium salt curing agent is selected from the quaternary ammonium salt curing agent and / or the quaternary phosphonium salt curing agent.

17. The optical coating composition according to claim 16, characterized in that, The quaternary ammonium salt curing agent is selected from one or more of tetra-n-butylammonium bromide, triethylbenzylammonium chloride, hexadecyl dimethyl benzylammonium chloride, or 1-n-dodecylpyridinium chloride; the quaternary phosphonium salt curing agent is tetra-n-butylphosphonium bromide or tetraphenylphosphonium bromide.

18. The optical coating composition according to claim 13, characterized in that, In the optical coating composition, the curing agent has a weight content of 0.0001~10wt%.

19. The optical coating composition according to claim 18, characterized in that, In the optical coating composition, the curing agent has a weight content of 0.001~5wt%.

20. The optical coating composition according to claim 19, characterized in that, In the optical coating composition, the curing agent has a weight content of 0.01~1wt%.

21. The optical coating composition according to any one of claims 1 to 4, characterized in that, The optical coating composition also includes component E: additives.

22. The optical coating composition according to claim 21, characterized in that, The additives are selected from one or more of antioxidants, ultraviolet absorbers, light stabilizers, or thickeners.

23. The optical coating composition according to claim 22, characterized in that, The antioxidant is selected from hindered phenolic compounds and / or phosphite compounds; The hindered phenolic compound is selected from one or more of 2,6-di-tert-butyl-4-ethylphenol, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol), 4,4'-butylene-bis-(3-methyl-6-tert-butylphenol), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 7-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate or tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane; The phosphite compounds are selected from one or more of tris(2,4-di-tert-butylphenyl) phosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl phosphite, tetra(2,4-di-tert-butylphenyl)[1,1-phenyl]-4,4'-diyl bisphosphite, or bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite.

24. The optical coating composition according to claim 22, characterized in that, The ultraviolet absorber is selected from benzophenone compounds and / or benzotriazole compounds; The benzophenone compounds are selected from one or more of 2-hydroxy-4-n-octyloxybenzophenone, 2,2-tetramethylenebis(3,1-benzoxazin-4-one) or 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; The benzotriazole compounds are selected from 2-(2'-hydroxy-5-methylphenyl)benzotriazole.

25. The optical coating composition according to claim 22, characterized in that, The light stabilizer is a hindered amine compound; The hindered amine compound is selected from one or more of the following: bis(2,2,6,6-tetramethyl-4-piperidinyl)selpicrate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl)selpicrate, graft copolymers obtained by polymerization of 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine with α-ene monomers, 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, bis-2,2,6,6-tetramethylpiperidinol sebate, or tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite.

26. The optical coating composition according to claim 22, characterized in that, The tackifier is selected from one or more of γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethylsilane, or 3-aminopropyltrimethylsilane.

27. The optical coating composition according to claim 22, characterized in that, In the optical coating composition, the additive has a weight content of 0.01~5wt%.

28. An optical coating, characterized in that, The optical coating is obtained by curing the optical coating composition according to any one of claims 1 to 27.

29. The optical coating according to claim 28, characterized in that, The curing process takes 0.01 to 2 hours.

30. The optical coating according to claim 29, characterized in that, The curing process is carried out at a temperature of 10~180℃.

31. The optical coating according to claim 30, characterized in that, The curing process is carried out at a temperature of 80~150℃.

32. A photovoltaic module, comprising solar cells, characterized in that, The outer surface of the battery cell is provided with an optical coating as described in any one of claims 28 to 31.

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