KR20170077465A

KR20170077465A - Photovoltaic cell module

Info

Publication number: KR20170077465A
Application number: KR1020150187373A
Authority: KR
Inventors: 정재식; 박효순; 이정연; 김현철
Original assignee: 주식회사 엘지화학
Priority date: 2015-12-28
Filing date: 2015-12-28
Publication date: 2017-07-06

Abstract

The present application relates to photovoltaic modules, fillers or uses thereof. The present application can provide a photovoltaic module having excellent durability and capable of stably maintaining such durability even under prolonged exposure to severe conditions such as high-temperature conditions or ultraviolet irradiation conditions, and a filler for manufacturing the same.

Description

{PHOTOVOLTAIC CELL MODULE}

The present application is directed to a photovoltaic module, a filler composition, or a filler sheet.

Photovoltaic cells are semiconductor devices that can convert light into electricity. When photovoltaic cells are exposed to light, they generate a voltage which causes a subsequent flow of electrons. The magnitude of the electron flow derived from this is proportional to the light impact intensity on the photovoltaic junction formed on the cell surface.

Typical types of photovoltaic cells include silicon wafer photovoltaic cells and thin film photovoltaic cells. A silicon wafer-based photovoltaic cell uses a wafer, which is a semiconductor material produced by using a single crystal or a polycrystalline ingot, as an active layer. In addition, the thin film-based photovoltaic cell uses a continuous layer of a semiconductor material deposited on a substrate, a ferroelectric or the like by a technique such as sputtering or chemical vapor deposition (CVD) as an active layer.

Both wafer-based photovoltaic cells and thin-film photovoltaic cells are required to have load-bearing support members. As the support member, a top layer (light-receiving substrate) such as a ferroelectric substance having light transmittance and disposed on the photovoltaic cell, and a back sheet disposed on the back surface of the photovoltaic cell are typical.

In order to protect the photovoltaic cell or the photovoltaic cell array, an encapsulant for protecting the photovoltaic cell or the photovoltaic cell array is present between the light receiving substrate and the back sheet. The filling material is present in a multilayer between the light receiving substrate and the back sheet, or exists as a single layer. EVA (ethylene vinyl acetate) based materials are commonly used as fillers. However, since the general-purpose EVA material is generally weak to ultraviolet rays, it is used in combination with an ultraviolet absorber or the like in order to prevent deterioration of physical properties due to ultraviolet rays.

Recently, a device that can be used for photoconductivity in the ultraviolet region has been developed among photovoltaic devices. When the general-purpose filler is applied to such a device, ultraviolet rays are absorbed by the filler and can not reach the device, so that the power generation efficiency is lowered.

The present application aims to provide a photovoltaic module, a filler composition or a filler sheet.

The present application relates to a backsheet, And a photoelectric cell or a photovoltaic array which is protected by a filler between the back sheet and the light receiving substrate, wherein the filler comprises an ethylene-alpha olefin copolymer, and the ultraviolet absorbing compound Is 0.1% by weight or less, and has ultraviolet transmittance.

The present application also relates to a filler composition comprising an ethylene-alpha olefin copolymer and having a UV absorbing compound content of 0.1 wt% or less and having ultraviolet transmittance.

The present application relates to a filler sheet containing an ethylene-alpha olefin copolymer and having an ultraviolet ray-permeable property with an ultraviolet ray absorbing compound content of 0.1 wt% or less.

In this application, it is possible to provide a photovoltaic module including a filler excellent in resistance to ultraviolet rays, and a filler for manufacturing the same, having characteristics of transmitting ultraviolet rays, particularly ultraviolet rays of a wavelength range that a device of the photovoltaic module can utilize for power generation have.

Figures 1 and 2 are schematic diagrams of an exemplary photovoltaic module.

The photovoltaic module of the present application comprises: a back sheet; A light receiving substrate disposed opposite to the back sheet, and a photovoltaic cell or a photovoltaic array which is protected by a filler between the back sheet and the light receiving substrate.

In this application, the type of the light-receiving substrate is not particularly limited, and general materials known in this field can be used without limitation. Typically, the light-receiving substrate of the photovoltaic module includes a glass substrate; Fluoropolymer sheet; A cyclic polyolefin-based polymer sheet; A polycarbonate-based polymer sheet; An acrylic polymer sheet; Materials having excellent light-permeability, electrical insulation, mechanical strength, physical strength, or chemical strength such as a polyamide-based polymer sheet or a polyester-based polymer sheet are used, but the materials applicable in the present application are not limited thereto. The thickness of the light-receiving substrate is not particularly limited and may be selected within a general category.

The type of the back sheet in the present application is also not particularly limited. Known backsheets include metal plates such as aluminum or metal foil; Fluoropolymer sheet; A cyclic polyolefin-based polymer sheet; A polycarbonate-based polymer sheet; An acrylic polymer sheet; A polyamide-based polymer sheet; A weather-resistant sheet such as a polyester-based polymer sheet; A laminated sheet of two or more of the above, or a composite sheet obtained by laminating the above-mentioned sheet and a barrier film. However, the material to which the present application is applied is not limited thereto. The thickness of the backsheet and the like are not particularly limited, and can be adjusted in a conventional category.

The photovoltaic cell or the photovoltaic cell array encapsulated with the filler between the light receiving substrate and the back sheet includes crystalline silicon such as single crystal or polycrystalline silicon; Amorphous silicon having a structure such as a single bond type or a tandem structure; Known materials manufactured by using compound semiconductors such as GaAs, InP, CdTe, or CuInSe2 may be used. In some cases, a hybrid of a thin film of polycrystalline silicon, thin film amorphous silicon or thin film crystal silicon and amorphous silicon may be used. Materials may be used, and other materials applicable to other photovoltaic cells may be used.

Figs. 1 and 2 are views showing exemplary photovoltaic modules of the present application. Fig. 1, the photovoltaic module of the present application comprises a light-receiving substrate 10; A back sheet 20; A photovoltaic or photovoltaic array 30; And filling materials 41 and 42. [ Typically, the silicon wafer-based photovoltaic module has the form as shown in Fig. On the other hand, the thin film type photovoltaic module generally has a form in which a photovoltaic cell or array 30 is deposited on a light receiving substrate 10, which is a ferroelectric, as shown in FIG. The back sheet 20 and the filling material 40 are similar to the case of Fig.

In the photovoltaic module, the filler material encapsulating the photovoltaic cell or array between the light receiving substrate and the back sheet contains an ethylene-alpha olefin copolymer and has ultraviolet transmittance. In particular, the photovoltaic device or its array can be utilized for power generation It has ultraviolet transmittance against the range. In order to ensure such permeability, the filler may or may not contain the ultraviolet absorbing compound in a minimum proportion. The proportion of the ultraviolet absorptive compound corresponding to the ultraviolet absorptive compound is limited as described above, whereby the problem of resistance to ultraviolet rays may be caused. However, in the present application, Can be obtained.

In one example, the ultraviolet absorbing compound may be included in the filler in a ratio of about 0.1 wt% or less, and may not be included in another example.

The filler may contain the ethylene-alpha olefin copolymer as a main component. The inclusion of the main component as above means that the copolymer is contained in the filler in an amount of 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, 85% Or 95% or more. The upper limit of the proportion of the copolymer in the filler is not particularly limited, and may be, for example, less than about 100%.

The term " ethylene-alpha olefin copolymer " refers to a copolymer of ethylene and an alpha olefin, and thus the copolymer may contain at least ethylene polymerized units and alpha olefin polymerized units. The term " polymerized unit " means a unit formed by polymerization of the corresponding monomer. A method of polymerizing ethylene and alpha olefin to form a copolymer is known.

The alpha olefins copolymerized with ethylene in the copolymer include diene olefin-based monomers or triene olefin-based monomers having two or more double bonds. The alpha olefin is generally an alpha olefin having 3 to 20 carbon atoms. Specific examples of alpha olefins include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-hexadecene, 1-hexadecene, 1-hexadecene, 1-hexadecene, 1-hexadecene, Pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene or 3-chloromethylstyrene. These monomers may be used alone or in combination of two or more. Butene, 1-pentene, 1-pentene, 1-hexene, 1-heptene, , 1-hexadecene or 1-aitocene; Or propylene, 1-butene, 1-hexene, and 4-methyl-1-pentene or 1-octene; Or 1-octene may be applied.

The molar ratio of ethylene polymerization units in the copolymer is at least 0.5 mol%, at least 1 mol%, at least 5 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, at least 25 mol%, at least 30 mol% , 40 mol% or more, 50 mol% or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more. The upper limit of the molar ratio of ethylene polymerization units is not particularly limited, but may be, for example, less than 100 mol% or 99 mol%.

The properties or structure of such an ethylene-alpha olefin copolymer, for example, its density, molecular weight, molecular weight distribution, MFR (melt flow rate) and the like are not particularly limited and known properties may be applied, The above characteristics can be appropriately modified.

The ethylene-alpha olefin copolymer may be a silane-modified copolymer. The silane-modified copolymer can be produced by grafting the copolymer with a silane compound described later.

When grafting with a silane compound is required, as the copolymer, a copolymer having a large amount of side chains can be used. Copolymers with many side chains can be grafted more efficiently. The ethylene-alpha olefin copolymer having many side chains generally has a low density and a low side chain, and generally has a high density.

In one example, the copolymer to which the silane compound is grafted may have a density of from about 0.85 g / cm3 to about 0.96 g / cm3, or from about 0.85 g / cm3 to about 0.92 g / cm3.

Also, the silane compound grafted copolymer may have a melt flow rate (MFR) of about 0.1 g / 10 min to about 50 g / 10 min at 190 캜, about 1.0 g / 10 min to about 50.0 g / 10 min Or from about 1.0 g / 10 min to about 30.0 g / 10 min.

The filler may further comprise a silane compound. Such silane compounds may be grafted to the copolymer as described above or may be present separately. Such a silane compound can cause the filler to exhibit good adhesion with other elements of the module. As the silane compound, for example, a compound represented by the following formula (4) can be used.

[Chemical Formula 4]

DSi (X) _m Y _(3-m)

D is an alkenyl group, an epoxy group, a (meth) acryloyloxy group, a (meth) acryloyloxyalkyl group, a hydrolyzable group which will be described later, X is a hydrolyzable residue bonded to a silicon atom; Y is a non-hydrolyzable residue bonded to a silicon atom; and m is a number within a range of 1 to 3.

In Formula 4, D is an alkenyl group, an epoxy group, an acryloyloxy group, a methacryloyloxy group, a hydrolyzable residue or a nonhydrolyzable residue. In the above, when D is an alkenyl group, an epoxy group, an acryloyloxy group or a methacryloyloxy group, the silane compound may be copolymerized or grafted with the ethylene-alpha olefin copolymer.

Examples of the alkenyl group include a straight chain, branched chain or cyclic alkenyl group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms. The alkenyl group may be optionally substituted with one or more substituents. As the alkenyl group, for example, a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group or an octenyl group can be used, .

As used herein, the term epoxy group may mean a monovalent moiety derived from a cyclic ether or a cyclic ether containing three ring constituent atoms, unless otherwise specified. As the epoxy group, a glycidyl group, an epoxy alkyl group, a glycidoxyalkyl group or an alicyclic epoxy group can be exemplified. The alicyclic epoxy group may be a monovalent residue derived from a compound containing a structure containing an aliphatic hydrocarbon ring structure and having a structure in which two carbon atoms forming the aliphatic hydrocarbon ring also form an epoxy group. As the alicyclic epoxy group, an alicyclic epoxy group having 6 to 12 carbons can be exemplified, and, for example, an epoxycyclohexyl group or an epoxycyclohexylalkyl group can be exemplified.

Examples of the hydrolyzable moieties (X and D) include a halogen atom, an alkoxy group, an aryloxy group, an acyloxy group, an alkylthio group or an alkyleneoxy group.

As the halogen atom, fluorine (F), chlorine (Cl), bromine (Br) or iodine (I) can be exemplified and preferably chlorine (Cl) can be exemplified.

The alkoxy group may be an alkoxy group having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkoxy group may be linear, branched or cyclic and may optionally be substituted by one or more substituents.

The aryl group contained in the aryloxy group includes not only an aryl group but also an aralkyl group or an arylalkyl group, and includes, for example, one or more benzene rings, or two or more benzene rings May refer to a monovalent residue derived from a compound or derivative thereof including a linked or condensed structure. The aryl group may be, for example, an aryl group having 6 to 25 carbon atoms, 6 to 21 carbon atoms, 6 to 18 carbon atoms, or 6 to 12 carbon atoms. Examples of the aryl group include a phenyl group, a dichlorophenyl group, a chlorophenyl group, a phenylethyl group, a phenylpropyl group, a benzyl group, a tolyl group, a xylyl group or a naphthyl group, A phenyl group can be exemplified. The aryl moiety may optionally be substituted by one or more substituents.

As the acyloxy group in the above, an acyloxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms or 1 to 12 carbon atoms may be exemplified, which may be optionally substituted with one or more substituents.

Examples of the alkylthio group include alkylthio groups having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms and 1 to 4 carbon atoms, An alkyleneoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms may be exemplified, and the alkylthio group or alkyleneoxy group may optionally be substituted with one or more substituents . &Lt; / RTI >

In one example, X in formula (4) may be alkoxy. The alkoxy group may be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. The alkoxy group may be a straight chain, branched chain or cyclic alkoxy group and may be optionally substituted by one or more substituents. As the alkoxy group, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group or a butoxy group can be exemplified, and preferably a methoxy group or an ethoxy group can be used, but the present invention is not limited thereto.

Examples of the non-hydrolysable residue of the above formula (4) include hydrogen, an alkyl group or an aryl group. As the aryl group in the above, the aryl group described for the aryloxy group of X may be exemplified.

In the above formula (1), m is a number from 1 to 3, and in another example, 2 or 3, or 3.

Examples of such silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentoxysilane, vinyltriphenoxysilane, Or vinyltriacetoxysilane, but the present invention is not limited thereto. Of course, the case where the moiety D in the general formula (4) is not the polymerizable moiety but the hydrolyzable or non-hydrolyzable moiety described above can also be applied.

The filler is used in an amount of 0.01 to 10 parts by weight, 0.01 to 8 parts by weight, 0.01 to 6 parts by weight, 0.01 to 4 parts by weight, 0.01 to 2 parts by weight, or 0.01 to 1 part by weight, based on 100 parts by weight of the copolymer Of the total.

The filler material may further comprise other components in addition to the above components. For example, the filler material may include a cross-linking agent, which causes the reaction of the components, that is, an ethylene-alpha olefin copolymer, an ultraviolet absorber and / or a silane coupling agent, .

As the crosslinking agent, known compounds can be used, and examples thereof include hydroperoxides such as diisopropylbenzene hydroperoxide and 2,5-dimethyl-2,5-di (hydroperoxy) hexane; Di-t-butylperoxide, t-butylcumylperoxide, dicumylperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) ) Di (t-butylperoxy) -3-cyclohexane, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane and 2,5- Alkyl peroxides; Diacyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzoyl peroxide, o-methylbenzoyl peroxide and 2,4-dichlorobenzoyl peroxide; butyl peroxyacetate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxy octoate, t-butyl peroxyisopropylcarbonate, t-butyl (Benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne- Peroxyesters such as tertiary; Organic peroxides such as ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, and azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) can be used .

The filler may also include other components such as light stabilizers and heat stabilizers.

The light stabilizer can capture the active species of photo-induced initiation in the filler and prevent photo-oxidation. Examples of the light stabilizer include, but are not limited to, a hindered amine compound or a hindered piperidine compound.

Examples of the thermal stabilizer include tris (2,4-di-tert-butylphenyl) phosphite, bis [2,4-bis (1,1-dimethylethyl) -6- methylphenyl] ethyl ester phosphorous acid, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4'-diyl bisphosphonate and bis Thermal stabilizers; Hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene, and the like, but the present invention is not limited thereto.

The content of the light stabilizer and / or the heat stabilizer is not particularly limited. The content of the additive can be appropriately selected in consideration of the use of the composition, the shape and the density of the additive, and can be appropriately adjusted within a range of 0.01 to 5 parts by weight based on 100 parts by weight of the copolymer.

In addition to the above components, the filler may suitably further include various additives known in the art depending on the application. For example, when a copolymer grafted with a silane compound is used as the ethylene-alpha olefin copolymer, a copolymer not grafted with the silane compound may be used.

This application is also directed to the filler materials described above. Such a filler may be in the form of a composition, that is, a mixture containing the above-mentioned components, or in a sheet form, that is, a mixture containing the above components may be formed into a sheet form. In the filler, the above-described components may be contained in a uniformly mixed state, or at least some of the components may be contained in a state of being physically or chemically reacted. In one example, the filler can be produced by molding the composition into a film or sheet shape by a molding method such as hot melt extrusion or T-die molding. The concrete components included in the filler material, the kind and the ratio thereof, and the like can be similarly applied.

In the above, the filler composition or sheet can be used as a filler material for encapsulating a photo-semiconductor device such as an LED or an OLED as well as the above-described photovoltaic module.

Such fillers may be in sheet or film form as described above. In this case, the thickness of the filler sheet can be adjusted to about 10 탆 to 2,000 탆, preferably about 100 탆 to 1250 탆, in consideration of the supporting efficiency and breakage possibility of the element, light weight of the apparatus, workability and the like. However, the film thickness of the filler material may be changed depending on the specific application to be applied.

The manner of producing the above-described module using such a filler composition or sheet is not particularly limited. For example, it can be produced by a usual molding method such as a lamination method in which a light receiving substrate, a filler, a photovoltaic cell or its array, a back sheet and the like are laminated in accordance with a target structure, and then vacuum- The process conditions of the lamination process are not particularly limited and can be generally carried out at a temperature of 90 to 230 캜 or 110 to 190 캜 for 5 to 60 minutes or 8 to 40 minutes.

10: Light receiving substrate
20: back sheet
30: Photovoltaic device or array
40, 41, 42: filler

Claims

Back sheet; And a photoelectric cell or a photovoltaic array which is protected by a filler between the back sheet and the light receiving substrate, wherein the filler comprises an ethylene-alpha olefin copolymer, and the ultraviolet absorbing compound Is 0.1 wt% or less, and has ultraviolet transmittance.

The photovoltaic module according to claim 1, wherein the ethylene-alpha olefin copolymer is a copolymer of ethylene and an alpha olefin, wherein the alpha olefin is an alpha olefin having 3 to 20 carbon atoms.

The photovoltaic module of claim 1, wherein the filler material does not comprise an ultraviolet absorbing compound.

The photovoltaic module of claim 1, wherein the filler further comprises a compound of formula (4):
[Chemical Formula 4]
DSi (X) _m Y _(3-m)
D is an alkenyl group, an epoxy group, a (meth) acryloyloxy group, a (meth) acryloyloxyalkyl group, a hydrolysable residue or a nonhydrolyzable residue, X is a hydrolysable residue, Y is a non- And m is a number in the range of 1 to 3.

5. The photovoltaic module of claim 4, wherein the compound of formula (4) is grafted onto the ethylene-alpha olefin copolymer of the filler.

5. The photovoltaic module according to claim 4, wherein the filler comprises 0.01 to 10 parts by weight of the compound of formula (4) relative to 100 parts by weight of the ethylene-alpha olefin copolymer.

The photovoltaic module according to claim 1, wherein the filler further comprises at least one selected from the group consisting of a crosslinking agent, a light stabilizer, and a heat stabilizer.

An ethylene-alpha olefin copolymer, wherein the content of the ultraviolet absorptive compound is 0.1 wt% or less, and has ultraviolet transmittance.

A filler sheet comprising an ethylene-alpha olefin copolymer and having an ultraviolet absorbing compound content of 0.1% by weight or less and having ultraviolet transmittance.