KR20120086997A - Photovoltaic cell module - Google Patents

Abstract

PURPOSE: A photovoltaic cell module is provided to prevent interlayer delamination or the bleaching or discoloration of an encapsulating material caused by long term usage or water penetration. CONSTITUTION: An encapsulating material(12) is located between an upper plate(10) and a lower plate(11). The encapsulating material includes a first layer(12a) and a second layer(12b). The first layer includes an aryl containing silicon resin. The first layer forms the upper layer of the encapsulating material. The second layer forms the lower layer of the encapsulating material.

Description

Photovoltaic Modules {Photovoltaic cell module}

The present invention relates to a photovoltaic module.

Photovoltaic cells are semiconductor devices that can convert light into electricity. When a photovoltaic cell is exposed to light, it generates a voltage that causes subsequent electron flow. The magnitude of the electron flow induced above is proportional to the intensity of light impingement on the photovoltaic junction formed on the cell surface.

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

Since both wafer type photovoltaic cells and thin film type photovoltaic cells have brittleness, a load bearing member is required. The support member is light transmissive and may be an upper layer, such as a ferroelectric, disposed over the photovoltaic cell. The support member may also be a back layer disposed on the backside of the photovoltaic cell. The photovoltaic module may comprise a top layer and a back layer at the same time, which are typically rigid materials such as glass plates; Flexible materials such as metal films or metal sheets; Or a plastic material such as polyimide.

The back layer is typically in the form of a rigid backskin for protecting the backside of the photovoltaic module, and various materials are known that can be applied thereto. Examples of such materials include ferroelectrics such as glass; Organic fluorine-based polymers such as ethylene tetrafluoroethylene (ETFE) or polyethylene terephthalate (PET) -based materials. The material may be applied to the module alone, or may be applied with a silicon-based and / or oxygen-based material such as SiO _x .

The photovoltaic module may comprise a photovoltaic array, which is a collection of photovoltaic cells electrically interconnected on a single photovoltaic cell or ferroelectric and / or substrate. The photovoltaic cell or photovoltaic array is encapsulated attached to the ferroelectric and / or the substrate by an encapsulant. The encapsulant is used to protect the battery from the outside and to laminate the ferroelectric or the substrate to form an integrated module.

Typically, the encapsulant is formed using the same or different encapsulant. Exemplary encapsulation materials include EVA (ethylene vinyl acetate) based materials or epoxy based materials. Such encapsulants are typically supplied in film form and laminated to cells and ferroelectrics and / or substrates.

However, existing encapsulants such as EVA-based materials are inferior in adhesion to other parts of glass and modules. Accordingly, when the photovoltaic module is used for a long time, peeling is easily caused between the layers of the module, which causes a decrease in the efficiency of the module or corrosion due to moisture penetration. In addition, the existing encapsulation material has a problem of deteriorating the UV resistance, causing a problem of discoloration or discoloration when used for a long time, lowering the efficiency of the module, generating stress during curing, damaging the module.

An object of the present invention is to provide a photovoltaic module.

The present invention, the upper substrate; Lower substrate; And a photovoltaic cell or photovoltaic array encapsulated by an encapsulant between the upper substrate and the lower substrate,

The encapsulant provides a photovoltaic module having a first layer comprising an aryl group-containing silicone resin and a second layer having a water transmittance of 1 to 100 g / cm ² · day.

Hereinafter, the photovoltaic module of the present invention will be described in detail.

The type of the upper substrate that can be used in the present invention is not particularly limited, and a general material known in the art may be used without limitation. Typically, the upper substrate of the photovoltaic module includes a glass substrate; Fluorine-based polymer sheets; Cyclic polyolefin-based polymer sheets; Polycarbonate-based polymer sheets; Acrylic polymer sheets; Although materials having excellent light transmittance, electrical insulation, mechanical strength, physical strength or chemical strength, such as polyamide-based polymer sheets or polyester-based polymer sheets, are used, the scope of the present invention is not limited thereto. In the present invention, the thickness of the upper substrate is not particularly limited and may be selected within a conventional range.

The type of the lower substrate that can be used in the present invention is also not particularly limited, and materials commonly used in the art may be used. Typically, the lower substrate includes a metal plate or metal foil such as aluminum; Fluorine-based polymer sheets; Cyclic polyolefin-based polymer sheets; Polycarbonate-based polymer sheets; Acrylic polymer sheets; Polyamide-based polymer sheets; Or a sheet having weather resistance such as a polyester polymer sheet; Among the above, two or more laminated sheets or a composite sheet in which the above-described sheet and barrier film are laminated are used, but the scope of the present invention is not limited thereto. In the present invention, the thickness of the lower substrate is not particularly limited, and may be adjusted in a conventional range.

In the photovoltaic module of the present invention, the type of photovoltaic cell or array thereof encapsulated with an encapsulant between the upper and lower substrates is also not particularly limited. In the present invention, the photovoltaic cell or photovoltaic array includes crystalline silicon such as monocrystalline or polycrystalline silicon; Amorphous silicon having a structure such as a single bonded or tandem structure; It may include a compound semiconductor such as GaAs, InP, CdTe or CuInSe _2, and in some cases, may also include a thin material of polycrystalline silicon, thin film amorphous silicon, or a hybrid material of thin film crystalline silicon and amorphous silicon. It is not limited to this.

The photovoltaic module of the invention comprises an encapsulant encapsulating a photovoltaic cell or a photovoltaic array. In the present invention, the encapsulant has a multi-layered structure including a first layer containing an aryl group-containing silicone resin and a second layer having a specific moisture transmittance. In the present invention, the encapsulant may have a two-layer structure consisting of only the first layer and the second layer, and in some cases, may have a multilayer structure in which other layers are additionally included in addition to the first and second layers. . When the sealing material of this invention contains another layer besides a 1st layer and a 2nd layer, the other layer may also contain the aryl group containing silicone resin of this invention mentioned later, Epoxy resin and EVA system resin as needed. Alternatively, the present invention may be made of a conventional encapsulant resin such as a silicone resin.

In the present invention, the positions of the first layer and the second layer included in the encapsulant are not particularly limited. In the present invention, for example, the first layer may form the upper layer of the encapsulant, and the second layer may form the lower layer of the encapsulant. By controlling the structure of the encapsulant as described above, while exhibiting excellent adhesion to the module parts, even when used for a long time to prevent discoloration or discoloration, the second layer present in the lower effectively blocks the moisture or moisture of the module The durability can be secured.

1 and 2 exemplarily illustrate the photovoltaic module of the present invention. As shown in FIG. 1, the photovoltaic module 1 of the present invention comprises: an upper substrate 10; Lower substrate 11; A photovoltaic cell or photovoltaic array 14 existing between the upper substrate 10 and the lower substrate 11; And encapsulation materials 12 and 13 encapsulating the photovoltaic cell or photovoltaic cell array 14. When the module 1 of the present invention has the structure of FIG. 1, the photovoltaic cell or photovoltaic cell array 14 may comprise a silicon-based material. In addition, in the module 1 of FIG. 1, the first layer included in the encapsulant may be any one of two layers 12a and 12b encapsulating the photovoltaic cell or photovoltaic array 14, and in some cases Both layers 12a and 12b may also form a first layer. In addition, the second layer that blocks the penetration of moisture or moisture from outside may form the lower layer 13.

2 is a diagram showing a photovoltaic module 2 according to another example of the present invention. As shown in Fig. 2, the module 2 of the present invention comprises: an upper substrate 10; Lower substrate 11; Photovoltaic or photovoltaic arrays 24; And encapsulants 12 and 13 encapsulating the photovoltaic cell or its array 24. In the structure of FIG. 2, the photovoltaic cell or array 24 thereof may be a layer of a compound semiconductor. In addition, in the structure of FIG. 2, the encapsulant may include a first layer 12 encapsulating the photovoltaic cell or photovoltaic cell array 24 and a second layer forming the lower layer 13.

The kind of aryl group-containing silicone resin included in the first layer of the encapsulant of the present invention is not particularly limited as long as it is a material excellent in adhesiveness to components of the module and excellent in light resistance, moisture resistance, durability and weather resistance.

In this invention, it is especially preferable to use the aryl group containing silicone resin which satisfy | fills the conditions of following General formula 1 for a 1st layer.

[Formula 1]

X ≥ 0.15

In Formula 1, X represents a molar ratio (aryl group / Si) of all aryl groups contained in the resin with respect to all silicon atoms contained in the resin.

In the present invention, X is preferably 0.2 or more, more preferably 0.3 or more.

In the present invention, the aryl group contained in the silicone resin may be preferably a phenyl group. By adjusting the molar ratio of the aryl group in the present invention as described above, it is possible to provide a sealing material excellent in light extraction efficiency, adhesive moisture permeability and durability with module parts. In the present invention, the upper limit of the molar ratio of the aryl group is not particularly limited, but in the case of 15 or more, the viscosity of the resin may be high, resulting in poor processability and impact resistance properties after curing.

In one example of the present invention, the aryl group-containing silicone resin is a resin represented by the average composition formula of the following formula (1), may be a resin containing a siloxane unit of the formula (2) or formula (3).

[Formula 1]

^{(R 1 R 2 R 3 SiO} 1/2) a (R 4 R 5 SiO 2/2) b (R 6 SiO 3/2) c (SiO 4/2) d

[Formula 2]

^{_{(R 7 R 8 SiO 2/}} 2)

(3)

(R ⁹ SiO _3/2)

In Formulas 1 to 3, R ¹ to R ⁶ are substituents directly bonded to silicon atoms, and each independently represent alkyl, aryl, hydrogen, hydroxy, epoxy, acryl, isocyanate, alkoxy, or alkenyl, At least one of R ¹ to R ⁶ represents aryl, a is 0 to 0.6, b is 0 to 0.98, c is 0 to 0.8, d is 0 to 0.4, and a + b + c + d is 1 R ⁷ and R ⁸ each independently represent alkyl or aryl, R ⁹ represents aryl, provided that b and c are not simultaneously 0, and R ⁷ and R ⁸ At least one of represents aryl.

In the present specification, the silicone resin is represented by the average composition formula of Formula 1, but the encapsulant includes a plurality of silicone resin components as well as the encapsulant comprises a single silicone resin having the average composition formula of Formula 1, wherein the resin Taking the average of the composition of the components also includes the case represented by the formula (1).

A silicone resin represented by the average composition formula of the formula (1) in the invention is represented by ^{(R 1 R 2 R 3 SiO} 1/2) a monofunctional siloxane unit (M ^{unit), (R 4 R 5 SiO} 2/2) represented by the a bifunctional siloxane unit (D unit) _{^{is, (R 6 SiO 3/2}} ) 4 -functional siloxane unit (Q unit) represented by the trifunctional siloxane unit (T unit), and (SiO _4/2) represented by the It includes at least one siloxane unit selected from, wherein at least one siloxane unit of the D unit or T unit may be represented by the formula (2) or (3).

In the average compositional formula of Formula 1, R ¹ to R ⁶ are substituents directly bonded to silicon atoms, preferably alkyl or aryl, and hydrogen, hydroxy, epoxy, acrylic, isocyanate, alkoxy or al for improving curing reaction and adhesion properties. Kenyl.

Alkyl in Formula 1 refers to linear, branched or cyclic alkyl having 1 to 12, preferably 1 to 8, more preferably 1 to 4 carbon atoms, specifically methyl, ethyl, propyl, isopropyl , Butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl or decyl and the like, and may be preferably methyl.

In addition, in the formula 1, alkoxy means linear, branched or cyclic alkoxy having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. Specifically, methoxy, ethoxy, Propoxy, isopropoxy, butoxy, isobutoxy or tert-butoxy and the like, preferably methoxy or ethoxy.

In addition, in the general formula (1), alkenyl means alkenyl having 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 4 carbon atoms, and specifically, a vinyl group, allyl group, propenyl group, and isopropenyl group. , Butenyl group, hexenyl group, cyclohexenyl group or octenyl group and the like may be included, preferably may be a vinyl group or allyl group.

In addition, in Formula 1, aryl is aryl having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and specifically, may include phenyl, tolyl, xylyl, naphthyl, and the like, and preferably phenylyl. Can be.

In the mean composition formula (1), a, b, c and d represent the mole fraction of each siloxane unit. In the mean compositional formula of Formula 1, a, b, c and d are the sum of 1, except that b and c are 0 at the same time. Specifically, in the average compositional formula of Formula 1, a is 0 to 0.6, preferably 0 to 0.5, b is 0 to 0.98, preferably 0 to 0.9, c is 0 to 0.8, preferably 0 to 0.7 And d is 0 to 0.4, preferably 0 to 0.2. In the present invention, by controlling the distribution ratio of the M, D, T and Q units in the silicone resin as described above, the bag excellent in adhesion, moisture resistance, moisture permeability, weather resistance, light resistance, hardness and UV resistance to the module parts, etc. Ash can be provided.

In the present invention, the silicone resin may include one or more aryl in the molecular structure, in consideration of physical properties such as light extraction efficiency, moisture permeability weather resistance and hardness, as shown in the average composition formula of Formula 1, preferably the aryl group is a phenyl group Can be.

In the silicone resin of the present invention, the aryl is preferably included in the D unit or the T unit, more preferably all of the aryl contained in the silicone resin of the average compositional formula of Formula 1 is included in the D and / or T unit, The D and T units may have a specific structure, that is, a structure represented by Formulas 2 and 3.

In Chemical Formulas 2 and 3, alkyl may preferably be alkyl having 1 to 8 carbon atoms, more preferably alkyl having 1 to 4 carbon atoms, still more preferably methyl.

In addition, in the formulas (2) and (3), the aryl may be preferably aryl having 6 to 12 carbon atoms, more preferably phenyl.

In the present invention, the unit of formula (2) is a bifunctional siloxane unit (D unit) included in the silicone resin, preferably a siloxane unit represented by the following formula (4) or (5).

[Formula 4]

(MePhSiO _2/2)

[Chemical Formula 5]

(Ph ₂ SiO _2/2)

In Formula 4 or 5, Me represents methyl and Ph represents phenyl.

In addition, in the present invention, the unit of formula (3) is a trifunctional siloxane unit (T unit) included in the silicone resin, preferably a unit represented by the following formula (6).

[Formula 6]

(PhSiO _3/2)

In Chemical Formula 6, Ph represents phenyl.

In the present invention, the silicone resin represented by the average compositional formula of Formula 1 may have a weight average molecular weight (M _w ) of 500 to 200,000, preferably 1,000 to 200,000. In the present invention, by adjusting the weight average molecular weight of the resin as described above, it is possible to maintain the excellent workability or workability in the sealing process, it is possible to provide a sealing material excellent in hardness, light resistance and durability. As used herein, the term "weight average molecular weight" means a conversion value with respect to standard polystyrene measured by gel permeation chromatography (GPC).

The silicone resin contained in the first layer in the present invention is not particularly limited as long as the above conditions are satisfied. The silicone resin of the present invention may have an average composition formula specifically, but is not limited thereto.

_{(ViMe 2 SiO 1/2)} 2 (Me 2 SiO 2/2) 30 (MePhSiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 3 (MePhSiO 2/2) 30 (Me 2 SiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 5 (Ph 2 SiO 2/2) 20 (Me 2 SiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (EpSiO 3/2) 5 (Ph 2 SiO 2/2) 10 (Me 2 SiO 2/2) 10

_{(ViMe 2 SiO 1/2)} 3 (PhSiO 3/2) 5

_{(ViMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10 (MeSiO 3/2) 2 (Me 2 SiO 2/2) 5

_{(ViMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10 (MeEpSiO 2/2) 5

_{(HMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10

_{(HMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10 (MeEpSiO 2/2) 5

_{(HMe 2 SiO 1/2)} 2 (Ph 2 SiO2 / 2) 1.5

_{(HMe 2 SiO 1/2)} 2 (Ph 2 SiO 2/2) 5 (Me 2 SiO 2/2) 5

_{(PhSiO 3/2) 10 (} MePhSiO 2/2) 10 (Me 2 SiO 2/2) 10

_{(PhSiO 3/2) 5 (} EpMeSiO 2/2) 2 (Me 2 SiO 2/2) 10

_{(PhSiO 3/2) 5 (} AcSiO 3/2) 5 (Me 2 SiO 2/2) 10

_{(AcSiO 3/2) 5 (} Me 2 SiO 2/2) 10 (Ph 2 SiO 2/2) 5

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 2 (Ph 2 SiO 2/2) 10 (Me 2 SiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (EpSiO 3/2) 3 (MePhSiO 2/2) 10 (Me 2 SiO 2/2) 20

_{(ViMe 2 SiO 1/2)} 3 (Me 2 SiO 2/2) 2 (PhSiO 3/2) 4 (MeSiO 3/2) 6

_{(HMe 2 SiO 1/2)} 2 (PhMeSiO 2/2) 1.5

Here, Vi represents a vinyl group, Me represents a methyl group, Ph represents a phenyl group, Ac represents an acryl group, and Ep represents an epoxy group.

In the present invention, the method of forming the encapsulant to include the silicone resin as described above is not particularly limited. In the present invention, for example, addition-curable silicone composition; Condensation or polycondensation curable silicone compositions; It is possible to appropriately employ various materials known in the art, such as an ultraviolet curable silicone composition or a peroxide vulcanized silicone composition, to form an encapsulant including the silicone resin as described above; Condensation or polycondensation curable silicone compositions; Or it is preferable to use an ultraviolet curable silicone composition, but it is not limited to this.

The addition-curable silicone composition is a composition capable of forming a silicone resin through hydrogen silicide, and when the composition is used, an organosilicon compound having a hydrogen atom (Si-H group) bonded to a silicon atom And an organosilicon compound having an alkenyl group bonded to a silicon atom can be reacted in the presence of a catalyst to produce a silicone resin.

In the case of a condensation or polycondensation curable silicone composition, an organic silane having a hydrolyzable functional group such as -Cl-OCH ₃ , -OC (O) CH ₃ , -N (CH ₃ ) ₂ , -NHCOCH _3, or -SCH ₃ Alternatively, the siloxane may be subjected to a hydrolysis or condensation reaction to prepare a silicone resin.

In the case of an ultraviolet curable silicone composition, hydrolysis or condensation of a functional group capable of initiating a polymerization reaction by ultraviolet light, for example, a silicon compound such as silane or siloxane containing (meth) acryl or vinyl, or a hydrolyzate thereof The silicone resin may be prepared by applying to the reaction, and irradiating ultraviolet rays to the silicone resin.

Various addition-curable types which can be selected according to the composition of a silicone resin desired in this field; Condensation or polycondensation curing type; Or ultraviolet curable silicone compositions; And conditions and reaction additives for producing silicone resins using such compositions are known. In the present invention, the above-described method may be suitably employed to form the first layer including the silicone resin of Chemical Formula 1 described above.

The sealing material of this invention also contains the 2nd layer which has a specific range of moisture permeability. In the present invention, the moisture permeability of the second layer may be preferably 1 to 100 g / cm ² · day, more preferably 1 to 50 g / cm ² · day. In the present invention, as described above, the second layer may form a lower layer of the encapsulant to effectively block external moisture or moisture from penetrating into the module. In addition, the moisture permeability in the present invention can be measured by mocon equipment.

In the present invention, the material constituting the second layer is not particularly limited as long as it can exhibit the water transmittance in the above-described range.

In the present invention, the second layer may be a polymer resin such as EVA or polyolefin resin.

In addition, in the present invention, the second layer is formed of an aryl group-containing silicone resin, preferably a phenyl group-containing silicone resin as in the case of the first layer, but by controlling the content of the aryl group contained in the resin in the above-mentioned range It is preferable to form a second layer having a moisture transmittance.

In one example of the present invention, the aryl group-containing silicone resin constituting the second layer may satisfy the following general formula (3).

[Formula 3]

Y ≥ 0.4

In the general formula (3), Y represents the average molar ratio (aryl group / Si) of the total aryl groups contained in the resin to the total silicon atoms contained in the silicone resin.

In the present invention, Y may preferably be 0.45 or more, more preferably 0.5 or more. In the present invention, the ratio of aryl in the silicone resin included in the second layer can be controlled as described above, so that the second layer can exert an excellent moisture and moisture barrier effect. In the present invention, the upper limit of the average molar ratio of the aryl group of the silicone resin constituting the second layer is not particularly limited. That is, in the present invention, the higher the average molar ratio of the aryl group of the resin of the second layer can exhibit excellent moisture or moisture barrier effect, and the upper limit may be appropriately adjusted in consideration of workability and the like.

In the present invention, the silicone resin forming the second layer may be more specifically a silicone resin represented by an average composition formula of the following Chemical Formula 7.

[Formula 7]

^{(R 10 R 11 R 12 SiO} 1/2) e (R 13 R 14 SiO 2/2) f (R 15 SiO 3/2) g (SiO 4/2) h

In Formula 7, R ¹⁰ to R ¹⁵ are substituents directly bonded to silicon atoms, and each independently represent alkyl, aryl, hydrogen, hydroxy, epoxy, acryl, isocyanate, alkoxy, or alkenyl, and R ^{10 At} least one of R ¹⁵ is aryl, e is 0 to 0.6, f is 0 to 0.98, g is 0 to 0.8, h is 0 to 0.4, provided that e + f + g + h is 1.

In the present specification, the silicone resin forming the second layer is represented by the average composition formula of Chemical Formula 7, wherein a single silicone resin included in the second layer is represented by Chemical Formula 7, as well as a plurality of silicones in the second layer. In the case where a resin component is present, the average of the composition of the resin component is taken as the case represented by the formula (7).

In the present invention, more specific types and preferred examples of R ¹⁰ to R ¹⁵ in the average compositional formula of Formula 7 are the same as those of R ¹ to R ⁶ .

In addition, in Formula 7, e, f, g, and h are mole fractions of M, D, T, and Q units constituting the silicone resin, and e is 0 to 0.6, preferably 0 to 0.5, and f is 0 to 0.98, preferably 0.2 to 0.9, g is 0 to 0.8, preferably 0.2 to 0.7, and h is 0 to 0.4, preferably 0 to 0.2. In the present invention, the distribution ratio of the M, D, T, and Q units in the silicone resin of the second layer is controlled as described above, and thus the adhesion, moisture resistance, moisture permeability, weather resistance, light resistance, hardness, and ultraviolet resistance with the module components are controlled. It is possible to provide an excellent sealing material.

In the silicone resin of the second layer of the present invention, aryl, similar to the silicone resin of the first layer, may be included in the D unit or the T unit, and preferably, the aryl contained in the silicone resin of the average composition formula All may be included in the D unit represented by the following formula (8) and / or the T unit represented by the following formula (9).

[Formula 8]

R ¹⁶ R ¹⁷ SiO _2/2

[Chemical Formula 9]

R ¹⁸ SiO _3/2

In Formulas 8 and 9, R ¹⁶ and R ¹⁷ are each independently alkyl or aryl, at least one of R ¹⁶ and R ¹⁷ is aryl, and R ¹⁸ is aryl.

In Formulas 8 and 9, more specific examples and preferred examples of alkyl and aryl are the same as those of Formulas 2 and 3.

In the present invention, the siloxane unit of Formula 8 may be more preferably a bifunctional siloxane unit of Formula 10 or 11, and the siloxane unit of Formula 9 may preferably be a siloxane unit of Formula 12.

[Formula 10]

(MePhSiO _2/2)

[Formula 11]

(Ph ₂ SiO _2/2)

[Chemical Formula 12]

(PhSiO _3/2)

In Formulas 10 to 12, Me represents methyl and Ph represents phenyl.

In the present invention, the silicone resin represented by the average compositional formula of Formula 4 may have a weight average molecular weight (M _w ) of 500 to 200,000, preferably 1,000 to 200,000. In the present invention, by adjusting the weight average molecular weight of the resin as described above, it is possible to maintain the excellent workability or workability in the sealing process, it is possible to provide a sealing material excellent in hardness, light resistance and durability.

The silicone resin contained in the second layer in the present invention is not particularly limited as long as the above conditions are satisfied. The silicone resin of the present invention may have an average composition formula specifically, but is not limited thereto.

_{(ViMe 2 SiO 1/2)} 2 (Me 2 SiO 2/2) 30 (MePhSiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 3 (MePhSiO 2/2) 30 (Me 2 SiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 5 (Ph 2 SiO 2/2) 20 (Me 2 SiO 2/2) 30

_{(ViMe 2 SiO 1/2)} 2 (EpSiO 3/2) 5 (Ph 2 SiO 2/2) 10 (Me 2 SiO 2/2) 10

_{(ViMe 2 SiO 1/2)} 3 (PhSiO 3/2) 5

_{(ViMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10 (MeSiO 3/2) 2 (Me 2 SiO 2/2) 5

_{(ViMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10 (MeEpSiO 2/2) 5

_{(HMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10

_{(HMe 2 SiO 1/2)} 3 (PhSiO 3/2) 10 (MeEpSiO 2/2) 5

_{(HMe 2 SiO 1/2)} 2 (Ph 2 SiO 2/2) 1.5

_{(HMe 2 SiO 1/2)} 2 (Ph 2 SiO 2/2) 5 (Me 2 SiO 2/2) 5

_{(PhSiO 3/2) 10 (} MePhSiO 2/2) 10 (Me 2 SiO 2/2) 10

_{(PhSiO 3/2) 5 (} EpMeSiO 2/2) 2 (Me 2 SiO 2/2) 10

_{(PhSiO 3/2) 5 (} AcSiO 3/2) 5 (Me 2 SiO 2/2) 10

_{(AcSiO 3/2) 5 (} Me 2 SiO 2/2) 10 (Ph 2 SiO 2/2) 5

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 2 (Ph 2 SiO 2/2) 12 (Me 2 SiO 2/2) 10

_{(ViMe 2 SiO 1/2)} 2 (EpMeSiO 2/2) 3 (PhSiO 2/2) 5 (PhMeSiO 2/2) 1

_{(ViMe 2 SiO 1/2)} 2 (PhSiO 2/2) 7 (PhMeSiO 2/2) 1

_{(HMe 2 SiO 1/2)} 2 (Ph 2 SiO 2/2) 1.5

Here, Vi represents a vinyl group, Me represents a methyl group, Ph represents a phenyl group, Ac represents an acryl group, and Ep represents an epoxy group.

In the present invention, the method of forming the encapsulant to include the silicone resin as described above is not particularly limited. In the present invention, for example, an addition-curable silicone composition selected according to the desired resin composition similarly to the case of the first layer; Condensation or polycondensation curable silicone compositions; The second layer can be formed using an ultraviolet curable silicone composition, a peroxide vulcanized silicone composition, or the like.

In the present invention, the method of manufacturing the photovoltaic module including each of the above components is not particularly limited, and various methods known to those skilled in the art may be employed without limitation.

In the present invention, for example, a photovoltaic module can be produced by preparing an encapsulant material in a hot melt sheet or liquid form, and applying it to an appropriate encapsulation method in consideration of a desired layer structure, and in particular, the liquid material It is appropriate to manufacture modules by direct coating method in terms of manufacturing cost and process efficiency.

As used herein, the term "high temperature meltable sheet" means a sheet-like molded article made of a sealing material. The hot melt sheet is a material that is present in an uncured or partially cured state prior to application, at room temperature rises in strength and flow resistance, converts to a low viscosity flowable material by heating, and can be highly viscous by cooling again. Can be. In this field, a method for producing the above-mentioned high temperature meltable sheet using each of the above materials is known.

When the hot melt sheet is used in the present invention, the module may be manufactured by stacking an upper substrate, a lower substrate, a photovoltaic cell or a photovoltaic cell array with the hot melt sheet and heat pressing according to the desired module structure.

In addition, when the liquid material is used in the present invention, the liquid material may be directly coated at a desired position in the process and then cured to manufacture a photovoltaic module.

However, in the present invention, the method of constructing the module using the above-described encapsulant material is not limited to the above-described method.

In the present invention, it is possible to provide a photovoltaic module having excellent durability that can prevent interlayer peeling, discoloration or discoloration of the module constituting the module caused by long-term use or moisture penetration. In addition, the present invention can provide a photovoltaic module having excellent power generation efficiency.

1 and 2 are cross-sectional views illustrating exemplary photovoltaic modules of the present invention.

Hereinafter, the present invention will be described in more detail through examples according to the present invention, but the scope of the present invention is not limited to the examples given below.

Example  One

After mixing 10 g of polysiloxane compound B, 200 g of polysiloxane resin C, and 60 g of polysiloxane resin D to 100 g of polysiloxane compound A, the catalyst (Platinum (0) -1, 3-divinyl-1,1,3,3-tetramethyldisiloxane) was further added and uniformly mixed with a stirrer to prepare an encapsulant first layer resin composition.

[Compound A]

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 2 (Ph 2 SiO 2/2) 10 (Me 2 SiO 2/2) 30

[Compound B]

_{(ViMe 2 SiO 1/2)} 2 (EpSiO 3/2) 3 (MePhSiO 2/2) 10 (Me 2 SiO 2/2) 20

[Compound C]

_{(ViMe 2 SiO 1/2)} 3 (Me 2 SiO 2/2) 2 (PhSiO 3/2) 4 (MeSiO 3/2) 6

[Compound D]

_{(HMe 2 SiO 1/2)} 2 (PhMeSiO 2/2) 1.5

After mixing 10 g of polysiloxane compound F, 200 g of polysiloxane resin G, and 60 g of polysiloxane resin H to 100 g of polysiloxane compound E, the catalyst (Platinum (0) -1, 3-divinyl-1,1,3,3-tetramethyldisiloxane) was further added and uniformly mixed with a stirrer to prepare an encapsulant second layer resin composition.

[Compound E]

_{(ViMe 2 SiO 1/2)} 2 (ViMeSiO 2/2) 2 (Ph 2 SiO 2/2) 12 (Me 2 SiO 2/2) 10

[Compound F]

_{(ViMe 2 SiO 1/2)} 2 (EpMeSiO 2/2) 3 (PhSiO 2/2) 5 (PhMeSiO 2/2) 1

[Compound G]

_{(ViMe 2 SiO 1/2)} 2 (PhSiO 2/2) 7 (PhMeSiO 2/2) 1

[Compound H]

_{(HMe 2 SiO 1/2)} 2 (Ph 2 SiO 2/2) 1.5

The encapsulant first layer resin composition was applied to a glass substrate for a photovoltaic module, and cured at 100 ° C. for 1 hour. Then, a photoelectric conversion element was placed on the cured coating solution and the encapsulant second layer resin composition was applied again. Thereafter, the applied coating solution was cured at 150 ° C. for 1 hour, and then the backsheet was thermocompressed to prepare a photovoltaic module.

Example  2

A photovoltaic module was manufactured in the same manner as in Example 1, except that 50 g of TiO ₂ was mixed and used in the encapsulant second layer resin composition.

Example  3

A photovoltaic module was manufactured in the same manner as in Example 1, except that EVA resin was used instead of the encapsulating material second layer resin composition.

Comparative example  One

The encapsulant photoelectric conversion element was encapsulated using the encapsulant sheet of the EVA series, which is generally used as an encapsulant for photovoltaic cells, without using the encapsulant first layer resin composition and the second layer resin composition prepared in Example 1. Except that, a photovoltaic module was manufactured in the same manner as in Example 1.

Comparative example  2

As the polysiloxane compound synthesized in a known manner, the compounds represented by the following formulas (I) to (K) were mixed to prepare siloxane compositions (mixture amount: compound I 100 g, compound J 20 g, compound K 50 g). Subsequently, a catalyst (Platinum (0) -1,3-divinyl-1,1,3,3-tetramethyldisiloxane) is added to the composition in an amount of 20 ppm of Pt (0), and uniformly mixed for encapsulation. A resin composition was prepared.

(I)

_{(ViPh 2 SiO 1/2)} 2 (Me 2 SiO 2/2) 20

[Formula J]

_{(ViPh 2 SiO 1/2)} 3 (MeSiO 3/2) 10

[Formula K]

_{(HMe 2 SiO 1/2)} 2 (HMeSiO 2/2) 2 (Me 2 SiO 2/2) 10

In the above formula, Vi represents a vinyl group, Me represents a methyl group, and Ph represents a phenyl group.

A photovoltaic module was manufactured in the same manner as in Example 1, except that the second layer resin composition for encapsulation material prepared in Example 1 was not used, and the composition was used as the first layer resin composition instead.

Test Example

1. Power Evaluation of Photovoltaic Modules

The efficiency of the photovoltaic modules prepared in Examples and Comparative Examples was investigated using a thumb simulator. Specifically, the light source of about 1 kW was irradiated to the glass substrate side of the manufactured module for the same time, and the power generation amount of the photovoltaic module was measured. The measured results are summarized in Table 1 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Power generation efficiency 9.3% 9.5% 9.5% 9.0%

2. Moisture Permeability Evaluation

A 1 mm thick specimen was prepared from the encapsulant second layer, and moisture permeability was measured using a mocon equipment, and the results are shown in Table 2 below.

3. Durability Reliability Evaluation

The durability of the specimens under high temperature and high humidity was measured in the following manner. Specifically, after coating the composition of Example 1, Comparative Example 1 and Comparative Example 2 on the acrylic plastic substrate and left for 500 hours at 85 ℃ / 85% after curing, the reliability is measured by the method of peel test, the results are shown in the following table 2 is described.

<Evaluation Criteria>

O: adhesive strength 15 gf / mm or more

X: less than 15 gf / mm

4. UV-resistant evaluation (Q-UV evaluation)

Each specimen was irradiated with light at 60 ° C. for 3 days with Q-UVA (340 nm, 0.89 W / Cm ² ) equipment, and yellowing was evaluated.

<Evaluation Criteria>

O: 450 nm absorbance less than 5% after light irradiation

X: 450 nm absorption after light irradiation 5% or more

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Moisture permeability
(g / cm ² ㆍ day) 20 25 15 10 120 Durability Reliability O O O O X UV resistance O O O X O

1, 2: photovoltaic module 10: upper substrate
11: lower substrate 14, 24: active layer
12, 12a, 12b, 13: encapsulant

Claims (13)

An upper substrate; A lower substrate; And a photovoltaic cell or photovoltaic array encapsulated by an encapsulant between the upper substrate and the lower substrate,
The encapsulant has a first layer comprising an aryl group-containing silicone resin and a second layer having a water transmittance of 1 to 100 g / cm ² · day. The photovoltaic module of claim 1 wherein the first layer forms an upper layer of the encapsulant and the second layer forms an lower layer of the encapsulant. The photovoltaic module of claim 1, wherein the aryl group-containing silicone resin included in the first layer satisfies the following general formula (1):
[Formula 1]
X ≥ 0.15
In General Formula 1, X represents a molar ratio (aryl group / Si) of all aryl groups contained in the resin relative to all silicon atoms contained in the resin. The photovoltaic module of claim 3, wherein the aryl group-containing silicone resin is a resin represented by an average composition formula of Formula 1, and is a resin including a siloxane unit of Formula 2 or Formula 3 below:
[Formula 1]
^{(R 1 R 2 R 3 SiO} 1/2) a (R 4 R 5 SiO 2/2) b (R 6 SiO 3/2) c (SiO 4/2) d
(2)
_{^{(R 7 R 8 SiO 2/}} 2)
(3)
(R ⁹ SiO _3/2)
In Formulas 1 to 3, R ¹ to R ⁶ are substituents directly bonded to silicon atoms, and each independently represent alkyl, aryl, hydrogen, hydroxy, epoxy, acryl, isocyanate, alkoxy, or alkenyl, At least one of R ¹ to R ⁶ represents aryl, a is 0 to 0.6, b is 0 to 0.98, c is 0 to 0.8, d is 0 to 0.4, and a + b + c + d is 1 R ⁷ and R ⁸ each independently represent alkyl or aryl, R ⁹ represents aryl, provided that b and c are not simultaneously 0, and R ⁷ and R ⁸ At least one of represents aryl. The photovoltaic module according to claim 4, wherein all of the aryl groups contained in the aryl group-containing silicone resin are contained in the siloxane units of the formula (2) or the siloxane units of the formula (3). The photovoltaic module of claim 5 wherein the siloxane units of Formula 2 are siloxane units of Formula 4 or 5 and the siloxane units of Formula 3 are siloxane units of Formula 6.
[Chemical Formula 4]
(MePhSiO _2/2)
[Chemical Formula 5]
(Ph ₂ SiO _2/2)
[Chemical Formula 6]
(PhSiO _3/2)
In Formulas 4 to 6, Me represents methyl and Ph represents phenyl. The photovoltaic module of claim 1, wherein the aryl group-containing silicone resin has a weight average molecular weight of 500 to 200,000. The photovoltaic module of claim 1, wherein the second layer comprises an aryl group-containing silicone resin that satisfies the conditions of the following general formula (3):
[Formula 3]
Y ≥ 0.4
In the general formula (3), Y represents the average molar ratio (aryl group / Si) of the total aryl groups contained in the resin to the total silicon atoms contained in the silicone resin of the second layer. The photovoltaic module of claim 8, wherein the aryl group-containing silicone resin included in the second layer is a silicone resin represented by an average composition formula of Formula 7
(7)
^{(R 10 R 11 R 12 SiO} 1/2) e (R 13 R 14 SiO 2/2) f (R 15 SiO 3/2) g (SiO 4/2) h
In Formula 7, R ¹⁰ to R ¹⁵ are substituents directly bonded to silicon atoms, and each independently represent alkyl, aryl, hydrogen, hydroxy, epoxy, acryl, isocyanate, alkoxy, or alkenyl, and R ^{10 At} least one of R ¹⁵ is aryl, e is 0 to 0.6, f is 0 to 0.98, g is 0 to 0.8, h is 0 to 0.4, provided that e + f + g + h is 1. The photovoltaic module of claim 9, wherein the silicone resin included in the second layer comprises a siloxane unit represented by Formula 8 or a siloxane unit represented by Formula 9 below:
[Chemical Formula 8]
R ¹⁶ R ¹⁷ SiO _2/2
[Chemical Formula 9]
R ¹⁸ SiO _3/2
In Formulas 8 and 9, R ¹⁶ and R ¹⁷ are each independently alkyl or aryl, at least one of R ¹⁶ and R ¹⁷ is aryl, and R ¹⁸ is aryl. The photovoltaic module of claim 10 wherein the siloxane units of formula 8 are siloxane units of formula 10 or 11 and the siloxane units of formula 9 are siloxane units of formula 12:
[Formula 10]
(MePhSiO _2/2)
(11)
(Ph ₂ SiO _2/2)
[Chemical Formula 12]
(PhSiO _3/2)
In Formulas 10 to 12, Me represents methyl and Ph represents phenyl. The photovoltaic module of claim 9, wherein the silicone resin represented by the average composition formula of Formula 7 has a weight average molecular weight of 500 to 200,000. The photovoltaic module of claim 1 wherein the second layer comprises an ethylene vinyl acetate (EVA) -based or polyolefin-based polymer resin.

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