Composition for solar cell encapsulant, solar cell encapsulant, and solar cell module

Abstract

Disclosed herein is a composition for a solar cell encapsulant, the composition comprising: (a) a first resin including an ethylene-based copolymer; and (b) a second resin including an aromatic vinyl-(meth)acrylate-based copolymer. According to the present invention, due to excellent light transmittance and anti-PID performance, it is possible to prevent a reduction in the electrical performance of a solar cell module and ensure the productivity of the solar cell module.

Description

Composition for solar cell encapsulant, solar cell encapsulant, and solar cell module

[0001] The present invention relates to a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module. More specifically, the present invention relates to a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module that have excellent light transmittance, provide anti-PID performance to prevent degradation of the electrical performance of the solar cell module, and ensure the productivity of the solar cell module.

[0002]

[0003] Previously, EVA (ethylene-vinyl acetate) was used as a solar cell encapsulant. However, using the above EVA can lead to the problem of PID (potential-induced degradation), which is a major cause of power output degradation in solar cell modules.

[0004] To address this, POE (polyolefin elastomer), EPE (EVA / POE / EVA 3-Layers film), etc. were used as a replacement for EVA in areas requiring anti-PID performance.

[0005] However, the aforementioned POE and EPE have the problem that they can reduce the productivity of solar cell modules and increase the defect rate of solar cell modules due to the reduced crosslinking speed and degree of crosslinking.

[0006] Therefore, it is necessary to develop a composition for solar cell encapsulant containing a resin with improved anti-PID performance while maintaining the productivity (crosslinking rate and degree of crosslinking) of solar cell modules.

[0007] Related prior art is Korean Patent Publication No. 10-2016-0129363.

[0008]

[0009] The objective of the present invention is to provide a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module that have excellent light transmittance and are endowed with anti-PID performance to prevent degradation of the electrical performance of a solar cell module.

[0010] Another objective of the present invention is to provide a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module that can effectively prevent the PID phenomenon and improve the long-term safety and durability of the solar cell module.

[0011] Another objective of the present invention is to provide a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module that can secure the productivity of a solar cell module by maintaining the crosslinking speed and degree of crosslinking, eliminate the problem of increased defect rates, and minimize the degradation of the output and lifespan of the solar cell module.

[0012] The above and other objectives of the present invention can all be achieved by the present invention described below.

[0013]

[0014] 1. One aspect of the present invention relates to a composition for a solar cell encapsulant. The composition for a solar cell encapsulant comprises (a) a first resin comprising an ethylene-based copolymer; and (b) a second resin comprising an aromatic vinyl-(meth)acrylic copolymer.

[0015] 2. In the above 1 embodiment, the first resin may have a melt index (ASTM D 1238, 190°C, 2.16 kg) of 2 to 35 g / 10 min.

[0016] 3. In the above 1 to 2 embodiments, the first resin may contain 15% to 40% by weight of a comonomer.

[0017] 4. In the above 1 to 3 embodiments, the second resin may have a weight-average molecular weight of 2,000 g / mol to 20,000 g / mol.

[0018] 5. In the above 1 to 4 embodiments, the second resin may have a glass transition temperature of 70°C to 250°C.

[0019] 6. In the above 1 to 5 embodiments, the weight ratio of the acrylic monomer, methacrylic monomer, and styrene monomer in the monomer mixture of the second resin may be 35 to 57: 5 to 10: 34 to 57.

[0020] 7. In the above 1 to 6 embodiments, the solar cell composition may contain 0.001 weight% to 1 weight% of the second resin.

[0021] 8. In the above embodiments 1 to 7, the composition for the solar cell encapsulant may contain 0.1% to 2.0% by weight of a crosslinking agent and 0.1% to 2.0% by weight of a crosslinking co-agent.

[0022] 9. Another aspect of the present invention relates to a solar cell encapsulant formed from the compositions for solar cell encapsulant of embodiments 1 to 8 above.

[0023] 10. Another aspect of the present invention relates to a solar cell module comprising the solar cell encapsulant of the 9th embodiment.

[0024] 11. In the above 10 embodiments, the solar cell module may have an output degradation rate of less than 5% calculated by the following Equation 1:

[0025] [Equation 1]

[0026] Output degradation rate (%) = ( P0 - P / P0) X 100

[0027] (P0 above is the initial output before the PID test, and P is the output after the PID test).

[0028]

[0029] The present invention has the effect of providing a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module that has excellent light transmittance, prevents degradation of the electrical performance of a solar cell module through anti-PID performance, can improve long-term safety and durability, and can secure the productivity of a solar cell module by maintaining the crosslinking rate and degree of crosslinking.

[0030]

[0031] The present invention will be described in more detail below. Where terms such as 'comprising,' 'having,' and 'consisting of' are used in this specification, other parts may be added unless 'only' is used. Where a component is expressed in the singular, it includes cases where it includes the plural unless specifically stated otherwise.

[0032] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0033] In addition, in the present invention, (meth)acrylic may include acrylic and / or methacrylic.

[0034] Hereinafter, a composition for a solar cell encapsulant, a solar cell encapsulant, and a solar cell module according to an embodiment of the present invention will be described in detail.

[0035]

[0036] Composition for solar cell encapsulant

[0037] One aspect of the present invention relates to a composition for a solar cell encapsulant.

[0038] Conventionally, to improve the performance of solar cell encapsulants, there is a method of adding inorganic compounds, including metal oxides, metal hydroxides, and zirconium phosphate compounds, to a base resin. While this method provides excellent PID improvement, it has the disadvantage of degrading optical properties, such as transparency, which is a key characteristic of solar cell encapsulants. Additionally, there is a method of adding krafting copolymers to improve the performance of solar cell encapsulants, but this has the disadvantage of having poor PID improvement.

[0039] A composition for a solar cell encapsulant according to one embodiment of the present invention is characterized by adding (b) a second resin comprising an aromatic vinyl-(meth)acrylic copolymer to (a) a first resin comprising an ethylene-based copolymer to minimize the degradation of optical properties and improve PID.

[0040]

[0041] (a) A first resin comprising an ethylene copolymer

[0042] The above ethylene-based copolymer is a copolymer obtained by polymerizing a mixture of two or more types of monomers, and can improve the long-term reliability and efficiency of a solar cell module by enhancing light transmittance, mechanical stability, electrical insulation, and durability. The monomers may include copolymers of ethylene, propylene, α-olefin, etc. In a specific example, the ethylene-based copolymer may include one or more of ethylene-vinyl acetate, ethylene-butyl acrylate, ethylene-ethyl acrylate, ethylene-acrylic acid, ethylene-methyl acrylate, and polyolefin elastomer. Preferably, ethylene-vinyl acetate may be included to ensure transparency.

[0043] The melt index of the first resin (ASTM D 1238, 190°C, 2.16 kg) may be 2 to 35 g / 10 min. In a specific example, the melt index may be 5 to 30 g / 10 min, for example, 8 to 25 g / 10 min. Within this range, there is no problem of reduced productivity of the solar cell module due to increased pressure of the extruder during sheet processing, and there is no problem of increased defect rate by maintaining the crosslinking speed and degree of crosslinking.

[0044] The first resin may contain 15% to 40% by weight of a comonomer. In a specific example, it may contain 17% to 38% by weight, for example, 20% to 35% by weight. Within the above range, light transmittance and adhesion may be excellent.

[0045]

[0046] (b) A second resin comprising an aromatic vinyl-(meth)acrylic copolymer

[0047] The above aromatic vinyl-(meth)acrylic copolymer can be prepared by polymerizing a monomer mixture comprising an acrylic monomer, a methacrylic monomer, and a styrene monomer. When a second resin containing the above aromatic vinyl-(meth)acrylic copolymer is used, the reduction in light transmittance can be minimized, and anti-PID performance can be imparted to prevent the degradation of the electrical performance of the solar cell module. The above acrylic monomer improves adhesion and optical transparency and may include one or more of acrylic acid, acrylonitrile, ethyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, and allyl acrylate. The above methacrylate monomer improves chemical resistance and optical transparency and may include one or more of methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, allyl methacrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate. The above styrene monomer improves electrical insulation and chemical resistance and may include one or more of styrene, α-methylstyrene, para-methylstyrene, divinylbenzene, and styrene halogenated. To ensure transparency, ethylene-vinyl acetate may preferably be included.

[0048] The second resin may have a weight-average molecular weight of 2,000 g / mol to 20,000 g / mol. In a specific example, the second resin may have a weight-average molecular weight of 3,000 g / mol to 15,000 g / mol, for example, 4,000 g / mol to 10,000 g / mol. Within this range, the decrease in light transmittance can be minimized, and the PID phenomenon can be effectively prevented, thereby improving the long-term safety and durability of the solar cell module.

[0049] The glass transition temperature of the second resin may be 70°C to 250°C. In a specific example, the glass transition temperature may be 80°C to 230°C, for example, 90°C to 200°C. Within this range, the decrease in light transmittance can be minimized, and the PID phenomenon can be effectively prevented, thereby improving the long-term safety and durability of the solar cell module.

[0050] The weight ratio of the acrylic monomer, methacrylate monomer, and styrene monomer in the monomer mixture of the second resin may be 35 to 57: 5 to 10: 34 to 57. In a specific example, the weight ratio may be 37 to 56: 6 to 9: 35 to 55, for example, 38 to 54: 6.5 to 8.5: 39 to 53. Within the above range, not only is the light transmittance excellent, but the PID phenomenon can also be effectively prevented, thereby improving the long-term safety and durability of the solar cell module.

[0051] Based on 100 parts by weight of the monomer mixture of the second resin, the composition may include 0.01 to 10 parts by weight of a polymerization initiator and 3 to 10 parts by weight of a solvent. In a specific example, the composition may include 0.05 to 8 parts by weight of the polymerization initiator, for example, 0.1 to 6 parts by weight. Also, in a specific example, the composition may include 4 to 9 parts by weight of the solvent, for example, 5 to 8 parts by weight. By maintaining electrical insulation within the above range, PID performance can be improved and light transmittance performance can be maintained.

[0052]

[0053] Composition for solar cell encapsulant

[0054] In another aspect of the present invention, the composition for the solar cell encapsulant comprises the first resin (a) and the second resin (b) to have excellent light transmittance and can improve PID.

[0055] In addition, the composition for the solar cell encapsulant may further include one or more of a crosslinking agent, a crosslinking co-agent, a silane coupling agent, a UV stabilizer, an antioxidant, and an anti-hydrolysis agent.

[0056] For example, the solar cell composition may contain 92% to 99% by weight of the first resin. In a specific example, it may contain 93% to 99% by weight, 94% to 99% by weight, 96% to 99% by weight, or 97% to 99% by weight. Within the above range, the composition may have excellent mixability and dispersibility, excellent light transmittance, excellent mechanical properties such as durability, and excellent electrical insulation.

[0057] For example, the solar cell composition may contain 0.001% to 1% by weight of the second resin. In a specific example, it may contain 0.005% to 0.8% by weight, for example, 0.01% to 0.5% by weight. Within this range, not only is the reduction in light transmittance minimized, but anti-PID performance is also imparted, thereby minimizing the reduction in output and lifespan of the solar cell module and improving the long-term safety and durability of the solar cell module.

[0058] The above-mentioned crosslinking agent can be used to improve mechanical strength, thermal stability, and chemical resistance by linking the molecular structure of the solar cell encapsulant. In a specific example, the above-mentioned crosslinking agent may include one or more selected from peroxyketals, peroxycarbonates, and dialkyl peroxides. In a specific example, the above-mentioned peroxyketal may include 1,1-di(tert-butylperoxy)cyclohexane, 1,1-di(tert-amylperoxy)cyclohexane, and 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane. The above peroxycarbonate may include one or more of tert-butylisopropylmonoperoxycarbonate, tert-amylperoxybenzoate, 2,5-dimethyl-2,5-di-(2-ethylhexanonylperoxy)hexane, tert-amylperoxy-2-ethylhexanoate, tert-butylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylperoxyacetate, and tert-butylperoxybenzoate. In a specific example, the dialkyl peroxide may include one or more of α,α'-di(tert-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di-tert-amyl peroxide, and di-tert-butyl peroxide.

[0059] The above composition for solar cell encapsulant may contain 0.1% to 2.0% by weight of a crosslinking agent. In a specific example, it may contain 0.3% to 1.8% by weight, for example, 0.5% to 1.5% by weight. Within the above range, the target degree of crosslinking can be sufficiently achieved, and the problem of deterioration of physical properties due to residual unreacted crosslinking agent can be improved.

[0060] The above crosslinking agent can be used to assist the crosslinking agent to increase the efficiency of the crosslinking reaction and to control the reaction rate to improve the physical properties of the solar cell encapsulant. In a specific example, the above crosslinking agent may include one or more selected from diallyl phthalate, diallyl fumarate, diallyl maleate, triallyl isocyanurate, triallyl cyanurate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate.

[0061] The above composition for solar cell encapsulant may contain 0.1% to 2.0% by weight of a crosslinking agent. In a specific example, it may contain 0.2% to 1.6% by weight, for example, 0.3% to 1.4% by weight. Within the above range, the target degree of crosslinking can be sufficiently achieved, and the problem of deterioration of physical properties due to residual crosslinking agent can be improved.

[0062] The above silane coupling agent is intended to improve adhesion between different materials, such as solar cell encapsulant and cell, and can be used to suppress moisture absorption and enhance durability through surface modification. In a specific example, the above silane coupling agent may include one or more selected from β-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, vinyl trichlorosilane, N-β-(aminoethyl)-γ-aminopropylmethyl dimethoxysilane, vinyl tris(β-methoxyethoxy)silane, vinyl triethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-chloropropyl trimethoxysilane.

[0063] The above composition for solar cell encapsulant may contain 0.1% to 1.0% by weight of a silane coupling agent. In a specific example, it may contain 0.3% to 0.8% by weight, for example, 0.4% to 0.6% by weight. Within this range, the adhesion strength is good when manufacturing solar cell modules, ensuring long-term performance.

[0064] The above-mentioned UV stabilizer can be used to prevent deterioration and discoloration of the solar cell encapsulant caused by ultraviolet rays, thereby maintaining transparency and extending the lifespan. In a specific example, the above-mentioned UV stabilizer may include one or more selected from 5'-di-tert-butylphenyl benzotriazole, bis-2,2,6,6-tetramethyl-4-piperidinyl sebacate, and 2-(2'-hydroxy-3', 2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole.

[0065] The above composition for solar cell encapsulant may contain 0.1% to 1.0% by weight of a UV stabilizer. In a specific example, it may contain 0.2% to 0.8% by weight, for example, 0.3% to 0.7% by weight.

[0066] The above antioxidant can be used to prevent the solar cell encapsulant from oxidizing and to suppress the deterioration of mechanical and chemical properties, thereby extending the lifespan of the solar cell module. In a specific embodiment, the above antioxidant may include one or more selected from hindered phenol-based, phosphite-based, and phenol-based types. For example, it may include one or more of 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), dilaurylthiodipropionate, dimyristylthiodipropionate, distearylthiopropionate, triphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, tris-diphenyl phosphite, diisodecylpentaerythritol diphosphite, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene.

[0067] The above composition for solar cell encapsulant may contain 0.01% to 0.5% by weight of an antioxidant. In a specific example, it may contain 0.05% to 0.2% by weight, for example, 0.08% to 0.15% by weight. Within this range, oxidative degradation of the solar cell encapsulant can be prevented, and mechanical strength and optical transmittance can be maintained.

[0068] The above hydrolysis inhibitor can be used to prevent deterioration caused by moisture in solar cell encapsulation materials and to maintain mechanical strength. In a specific example, the above hydrolysis inhibitor may include one or more selected from carbodiimide, epoxy compounds, vinyltrimethoxysilane, phosphate esters, and calcium carbonate.

[0069] The above composition for solar cell encapsulant may contain 0.05% to 0.5% by weight of a hydrolysis inhibitor. In a specific example, it may contain 0.07% to 0.4% by weight, for example, 0.1% to 0.3% by weight. Within this range, the long-term stability of the solar cell encapsulant may be prevented from deteriorating, and mechanical strength and optical transmittance may be maintained.

[0070]

[0071] Solar cell encapsulant

[0072] Another aspect of the present invention relates to a solar cell encapsulant formed from the above-described composition for solar cell encapsulant. According to one embodiment of the present invention, a solar cell encapsulant can be manufactured by introducing a first resin (a) and a second resin (b) into a high-speed shear-type mixer, a batch-type mixer, or a ribbon blender to mix them, then melt-kneading them using an extruder or the like, and extruding the mixture into a pellet shape. Alternatively, the mixture may be processed into a sheet shape after melt-kneading and then molded into a pellet shape.

[0073] It is preferable to use the above solar cell encapsulant by forming the composition for the solar cell encapsulant into a sheet. The above solar cell encapsulant composition can be manufactured by forming it into a sheet using a T-die extruder, a roll-to-roll molding machine, etc. During the molding process, one or more of the crosslinking agent, crosslinking co-agent, silane coupling agent, UV stabilizer, antioxidant, and hydrolysis inhibitor may be added.

[0074] The thickness of the solar cell encapsulant may be 0.08 mm to 2.5 mm. In a specific example, the thickness may be 0.15 mm to 1.5 mm, for example, 0.25 mm to 0.8 mm. Within this range, not only is light transmittance excellent, but the PID phenomenon can also be effectively prevented, thereby improving the long-term safety and durability of the solar module.

[0075]

[0076] solar cell module

[0077] Another aspect of the present invention relates to a solar cell module comprising the solar cell encapsulant described above. A solar cell module according to one embodiment of the present invention may have an output degradation rate of less than 5%, calculated by the following Equation 1:

[0078] [Equation 1]

[0079] Output degradation rate (%) = ( P0 - P / P0) X 100

[0080] (P0 above is the initial output before the PID test, and P is the output after the PID test).

[0081] When the output degradation rate of Equation 1 above satisfies 5% or less, the anti-PID performance is excellent, which prevents the degradation of the electrical performance of the solar cell module and can improve the long-term safety and durability of the solar cell module. In one embodiment, the output degradation rate may be less than 5%, less than 4%, 0.5~4%, or 1.5~4%.

[0082] On the other hand, when EVA is used alone among ethylene copolymers, the output degradation rate after the PID test is approximately 10%. That is, the present invention provides anti-PID performance, thereby preventing the degradation of the electrical performance of the solar cell module and improving the long-term safety and durability of the solar cell module.

[0083] For example, the PID test of the above solar cell module can be performed in accordance with the IEC 62804 standard.

[0084] The above solar cell module may include a transparent protective substrate, a first solar cell encapsulant, a solar cell, a second solar cell encapsulant, and a back side protective member that are sequentially stacked. For example, the above solar cell module may include a form in which the components are stacked in the order of a transparent protective substrate, a first solar cell encapsulant, a solar cell, a second solar cell encapsulant, and a back side protective member. That is, a solar cell module can be manufactured by encapsulanting and covering a solar cell with a pair of solar cell encapsulants. The first solar cell encapsulant and the second solar cell encapsulant may include the solar cell encapsulant described above. Both the transparent protective substrate and the back side protective member may be glass, or may include a sheet material having a structure in which an aluminum sheet is encapsulanted with a vinyl fluoride sheet or a hydrolyzable polyethylene terephthalate sheet. The above solar cell may include various materials such as silicon-based materials like monocrystalline silicon, polycrystalline silicon, and amorphous silicon, as well as gallium-arsenide and organic thin-film semiconductor materials.

[0085] The above solar cell module maintains the crosslinking speed and degree of crosslinking to ensure productivity, eliminates the problem of increased defect rates, and minimizes the degradation of the solar cell module's output and lifespan.

[0086]

[0087] Hereinafter, the structure and operation of the present invention will be explained in more detail through preferred embodiments. However, these are presented as preferred examples of the present invention and should not be interpreted in any way as limiting the present invention. Details not described herein can be sufficiently technically inferred by those skilled in the art, so such descriptions will be omitted.

[0088]

[0089] Examples and Comparative Examples

[0090] Example 1

[0091] As resin materials, 98.22 wt% of a first resin containing ethylene-vinyl acetate (EVA) containing 20 wt% of a comonomer (vinyl acetate (VA)) and 0.1 wt% of a second resin prepared by polymerizing ethyl acrylate (EA), methyl methacrylate (MMA), and α-methylstyrene (α-MS) in a weight ratio of 35:10:55 were used. The content of the first resin and the second resin is based on the total weight of the composition for solar cell encapsulant.

[0092] The above first resin and second resin were fed into a high-speed shear type mixer and mixed to prepare a composition for a solar cell encapsulant. Then, the composition for the solar cell encapsulant was melt-kneaded under conditions of an internal resin temperature of 100°C in an extruder, extruded using a T-die extruder, and then molded into a sheet to produce a solar cell encapsulant with a thickness of 0.5 mm, and a solar cell module containing the same was manufactured.

[0093] When mixing the first resin and the second resin, based on the total weight of the composition for the solar cell encapsulant, 0.5 wt% of a crosslinking agent (dicumyl peroxide), 0.5 wt% of a crosslinking co-agent (diallyl fumarate), 0.2 wt% of a silane coupling agent (vinyl trichlorosilane), 0.3 wt% of a UV stabilizer (bis-2,2,6,6-tetramethyl-4-piperidinyl sebacate), 0.1 wt% of an antioxidant (triphenyl phosphite), and 0.08 wt% of a hydrolysis inhibitor (carbodiimide) were added together.

[0094]

[0095] Example 2

[0096] A solar cell module was fabricated in the same manner as in Example 1, except that 97.82 wt% of a first resin containing the above-mentioned ethylene-vinyl acetate (EVA) and 0.5 wt% of a second resin prepared by polymerizing the above-mentioned ethyl acrylate (EA), methyl methacrylate (MMA), and α-methylstyrene (α-MS) were used as the resin material.

[0097]

[0098] Example 3

[0099] A solar cell module was fabricated in the same manner as in Example 1, except that 98.22 wt% of a first resin containing ethylene-ethyl acrylate (EEA) and 0.1 wt% of a second resin prepared by polymerizing acrylic acid (AA), allyl methacrylate (AMA), and o-chlorostyrene (o-CS) were applied as resin materials.

[0100]

[0101] Example 4

[0102] A solar cell module was fabricated in the same manner as in Example 3, except that 97.82 wt% of a first resin containing ethylene-ethyl acrylate (EEA) and 0.5 wt% of a second resin prepared by polymerizing acrylic acid (AA), allyl methacrylate (AMA), and o-chlorostyrene (o-CS) were applied as resin materials.

[0103]

[0104] Example 5

[0105] A solar cell module was fabricated in the same manner as in Example 1, except that 98.22 wt% of a first resin containing ethylene-butyl acrylate (EBA) and 0.1 wt% of a second resin prepared by polymerizing acrylonitrile (AN), glycidyl methacrylate (GMA), and para-methylstyrene (p-MS) were used as the resin material.

[0106]

[0107] Example 6

[0108] A solar cell module was fabricated in the same manner as in Example 5, except that 97.82 wt% of a first resin containing ethylene-butyl acrylate (EBA) and 0.5 wt% of a second resin prepared by polymerizing acrylonitrile (AN), glycidyl methacrylate (GMA), and para-methylstyrene (p-MS) were used as the resin material.

[0109]

[0110] Comparative Example 1

[0111] A solar cell module was manufactured in the same manner as in Example 1, except that the second resin was not used as the resin material, and 98.32 weight% of the first resin containing ethylene-vinyl acetate (EVA) was applied.

[0112]

[0113] Comparative Example 2

[0114] A solar cell module was manufactured in the same manner as in Example 1, except that the second resin was not used as the resin material, and 98.32 weight% of the first resin containing ethylene-ethyl acrylate (EEA) was applied.

[0115]

[0116] Comparative Example 3

[0117] A solar cell module was manufactured in the same manner as in Example 1, except that the second resin was not used as the resin material, and 98.32 weight% of the first resin containing ethylene-butyl acrylate (EBA) was applied.

[0118]

[0119] Comparative Example 4

[0120] A solar cell module was manufactured in the same manner as in Example 1, except that 97.82 wt% of a first resin containing ethylene-vinyl acetate (EVA) and 0.5 wt% of polyurethane (PU) were used as the resin material.

[0121]

[0122] Comparative Example 5

[0123] A solar cell module was manufactured in the same manner as in Example 1, except that 97.82 wt% of a first resin containing the above-mentioned ethylene-vinyl acetate (EVA) and 0.5 wt% of an epoxy resin (ER) were used as the resin material.

[0124]

[0125] Experimental Example

[0126] The physical properties of the examples and comparative examples were evaluated using the following method, and the results are shown in Table 1.

[0127] (1) Output degradation rate (%): Potential Induced Degradation (PID) tests were conducted on the solar cell modules of the above examples and comparative examples in accordance with IEC 62804.

[0128] The above PID test measured the initial output of the front and rear sides while applying a voltage of 1500V to the solar cell module, and then measured the output of the front and rear sides after exposure for 192 hours under conditions of 85℃ and 85% relative humidity.

[0129] In addition, the output (P0) before the PID test and the output (P) after the PID test of the solar cell modules of the above examples and comparative examples were each measured using a solar module simulator (McScience, Product Name: K3000 LED300 Solar Cell IV Test System). The solar module simulator is a device that evaluates the performance of a module by irradiating light onto the module surface to induce power generation and measuring the resulting power output. Furthermore, the output degradation rate was calculated according to Equation 1 below using the output values ​​before and after the PID test:

[0130] [Equation 1]

[0131] Output degradation rate (%) = ( P0 - P / P0) Υ 100

[0132] (P0 above is the initial output before the PID test, and P is the output after the PID test).

[0133] [Table 1]

[0134]

[0135] Referring to Table 1 above, it can be seen that the output degradation rate of the solar cell module in Examples 1 to 6 is less than 5%. On the other hand, it can be seen that the output degradation rate of the solar cell module in Comparative Examples 1 to 5 exceeds 5%.

[0136] Through this, it can be seen that the present invention can provide a solar cell module including a solar cell encapsulant in which the reduction in output value is significantly mitigated.

[0137]

[0138] The present invention has been described above with reference to embodiments. Those skilled in the art will understand that the present invention may be embodied in modified forms without departing from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalents should be interpreted as being included in the invention.

Claims

1. (a) A first resin comprising an ethylene-based copolymer; and (b) a second resin comprising an aromatic vinyl-(meth)acrylic copolymer; a composition for a solar cell encapsulant comprising.

2. A composition for a solar cell encapsulant according to claim 1, wherein the first resin has a melt index (ASTM D 1238, 190℃, 2.16kg) of 2 to 35 g / 10 min.

3. A composition for a solar cell encapsulant according to claim 1, wherein the first resin comprises 15% to 40% by weight of a comonomer.

4. A composition for a solar cell encapsulant according to claim 1, wherein the second resin has a weight-average molecular weight of 2,000 g / mol to 20,000 g / mol.

5. A composition for a solar cell encapsulant, wherein the second resin in claim 1 has a glass transition temperature of 70°C to 250°C.

6. A composition for a solar cell encapsulant according to claim 1, wherein the weight ratio of the acrylic monomer, the methacrylic monomer, and the styrene monomer in the monomer mixture of the second resin is 35 to 57: 5 to 10: 34 to 57.

7. A composition for a solar cell encapsulant according to claim 1, wherein the composition for the solar cell encapsulant comprises 0.001% to 1% by weight of the second resin.

8. The composition for a solar cell encapsulant according to claim 1, wherein the composition for the solar cell encapsulant comprises 0.1% to 2.0% by weight of a crosslinking agent and 0.1% to 2.0% by weight of a crosslinking co-agent.

9. A solar cell encapsulant formed from a composition for a solar cell encapsulant according to any one of claims 1 to 8.

10. A solar cell module comprising a solar cell encapsulant according to paragraph 9.

11. In claim 10, the solar cell module is a solar cell module having an output degradation rate of less than 5% as calculated by the following Equation 1: [Equation 1] Output degradation rate (%) = ( P0 - P / P0) X 100 (P0 above is the initial output before the PID test, and P is the output after the PID test).

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