KR20140105512A - Method of forming an encapsulant layer for a photovoltaic cell module - Google Patents

Abstract

A method of forming an encapsulant layer for a photovoltaic cell module comprising an photovoltaic cell layer and an outer layer spaced apart from the photovoltaic cell layer is characterized in that a kinematic viscosity at 25 [deg. And less than about 0.001 m ² / s (1,000 centistokes (cSt)). The method further comprises polymerizing the silicone composition at a location between the photovoltaic cell layer and the outer layer to form an encapsulant layer within the photovolatile battery module.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a photovoltaic cell module,

The present invention relates generally to an encapsulant layer for a photovoltaic cell module, and more particularly to a method for forming an encapsulant layer for a photovoltaic cell module in situ.

Photovoltaic cell modules are well known in the art and are available in a variety of sizes and shapes depending on the particular climate in which the desired power and photovoltaic cell modules are utilized. For example, the photovoltaic module may be cylindrical or rectangular. The cylindrical photovoltaic cell module generally includes an outer cylinder and an inner cylinder disposed within the outer cylinder. In particular, the inner cylinder is a photovoltaic layer and the outer cylinder is an outer layer, and the encapsulant layer is disposed therebetween. The viscous silicone gel is not used as a sealant layer in a cylindrical photovoltaic cell module because such a viscous silicone gel can not be poured or otherwise disposed between the inner and outer cylinders without the introduction of entrapped air, Air adversely affects the output and efficiency of the photovoltaic cell module. Additionally, the pressure required to introduce such a viscous silicone gel can damage or otherwise damage the photovoltaic cell layer and / or the outer layer. Thus, a silicone fluid is typically used to form the encapsulant layer of a cylindrical photovolatile battery module. However, silicone fluids often contain significant amounts of expensive monomodal silicon compounds, such as hexamethyldisiloxane, to lower the viscosity of the silicone fluid so that the silicone fluids can be poured easily. Moreover, when the cylindrical photovoltaic cell is damaged, the silicone fluid flows out from the cylindrical photovoltaic module, that is, leaks, which greatly reduces the output and efficiency of the cylindrical photovoltaic module.

The present invention provides a method of forming an encapsulant layer for a photovoltaic module comprising an photovoltaic cell layer and an outer layer spaced from the photovoltaic cell layer. The method includes disposing a photovoltaic cell layer, and dynamic viscosity (kinematic viscosity) is greater than 0 to about 0.001 m ² / s silicone composition is less than (1000 centistokes (cSt)) in between the outer layers, 25 ℃. The method further comprises polymerizing the silicone composition at a location between the photovoltaic cell layer and the outer layer to form an encapsulant layer within the photovolatile battery module.

Other advantages and aspects of the present invention can be described in the following detailed description when considered in connection with the accompanying drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic plan view of a photovoltaic cell module comprising an encapsulant layer between a photovoltaic cell layer and an outer layer spaced from the photovoltaic cell layer.
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2 is a schematic perspective view of a photovoltaic cell module including an encapsulant layer between an photovoltaic cell layer and an outer layer spaced apart from the photovoltaic cell layer.

Referring to the drawings in which like reference numerals designate corresponding parts throughout the several views, the photovoltaic battery module 10 is schematically illustrated. The present invention provides a method of forming an encapsulant layer (12) for a photovoltaic module (10). The method of the present invention is particularly suitable for forming the encapsulant layer 12 for a cylindrical photovoltaic module. Alternatively, the method of the present invention can be applied to a photovoltaic cell module other than the cylindrical photovoltaic cell module, or to applications other than the photovoltaic cell module.

The method includes placing a silicone composition between an photovoltaic cell layer (14) of the photovoltaic cell module (10) and an outer layer (16) spaced from the photovoltaic cell layer (14). Placing the silicone composition between the photovolumedia cell layer 14 and the outer layer 16 typically involves pouring the silicone composition between the photovoltaic cell layer 14 and the outer layer 16. Specifically, the silicone composition has a kinematic viscosity at 25 캜, which allows the silicone composition to flow or swell. The silicone composition may be applied to the photovoltaic cell layer 14 and the outer layer 16 without needing to apply pressure that may damage, crack, or otherwise damage the photovoltaic cell layer 14 and / 16). ≪ / RTI > The step of disposing the silicone composition between the photovoltaic cell layer 14 and the outer layer 16 may be performed by hand or through suitable equipment.

The silicone composition is less than the dynamic viscosity is from greater than 0 to about 0.001 m ² / s (1,000 centistokes (cSt)) at 25 ℃, alternatively 0.0005 m ² / s is less than (500 cSt), alternatively 0.0003 m ² / s ( 300 cSt) is less than, less than Alternatively 0.0001 m ² / s (cSt less than 100), alternatively, ^{5E-5 m 2 / s (} 50 cSt). As is readily understood in the art, the kinematic viscosity of a fluid is determined by the standard test method (and the calculation of kinematic viscosity) for the kinematic viscosity of transparent and opaque liquids (" Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids of Dynamic Viscosity) according to ASTM D-445 (2011). Silicone composition, and a kinematic viscosity at 25 ℃ less than ^{0.001 m 2 / s (1,000 cSt} ), is polymerized in situ siloxane (i. E., Si-O-Si) include any silicone composition capable of forming a bond . The kinematic viscosity relates to the silicone composition before polymerization and / or crosslinking. Thus, in order to achieve the kinematic viscosity at 25 ℃ of less than ^{0.001 m 2 / s (1,000 cSt} ), the silicone composition is generally monomeric and / or oligomeric silane, siloxane, other organic silicon compound, or a combination thereof do.

In certain embodiments, the silicone composition comprises at least one monomeric cyclosiloxane. For clarity, at least one monomeric cyclosiloxane is generically referred to herein as merely "monomeric cyclosiloxanes", but the silicone composition may include a variety of blends of more than one monomeric cyclosiloxane and different monomeric cyclosiloxanes have.

Monomeric cyclosiloxanes are cyclic siloxanes having repeating siloxane bonds and two monovalent groups, typically monovalent hydrocarbon groups, attached to each silicon atom of the cyclosiloxane. Monomeric cyclosiloxanes may have the general formula (R ¹ R ² SiO ₂ ) _x wherein R ¹ and R ² are independently selected from substituted or unsubstituted hydrocarbyl groups having from 1 to 10 carbon atoms , and x is an integer of 3 to 10. Specific examples of the unsubstituted hydrocarbyl group include alkyl groups such as methyl, ethyl, n-propyl, 1-methylethyl, butyl, 1-methylpropyl, , A dimethylethyl group, a pentyl group, a 1-methylbutyl group, a 1-ethylpropyl group, a 2-methylbutyl group and the like; An alkenyl group such as a vinyl group, an allyl group, a propenyl group, a hexenyl group and the like; Cycloalkyl groups such as cyclopentyl, cyclohexyl, methylcyclohexyl and the like; Aryl groups such as phenyl group, naphthyl group and the like; Alkaryl groups such as tolyl group, xylyl group and the like; Arylalkyl groups such as benzyl group, phenethyl group, phenpropyl group and the like; Aralkenyl groups such as styryl groups and the like; And an alkynyl group such as an ethynyl group and a propynyl group. The substituted hydrocarbyl group includes, for example, a hydrocarbyl group substituted with a halogen atom. An example of a substituted hydrocarbyl group is a trifluoropropyl group. Typically, at least 80% of all R ¹ and R ² are methyl groups or phenyl groups, with methyl groups being more typical. Most typically, all or substantially all of R ¹ and R ² are methyl groups.

When R ¹ and R ² are methyl groups, the monomeric cyclosiloxane is generally referred to in the art as a number followed by the letter D, where the numbers represent the number of silicon atoms in the particular monomeric cyclosiloxane. For example, when R ¹ and R ² are methyl groups, a monomeric cyclosiloxane having three silicon atoms is referred to as D ₃ , a monomeric cyclosiloxane having four silicon atoms is referred to as D ₄ , and five monomeric cyclosiloxane having a silicon atom is such, referred to as D _5. Thus, when the silicone composition comprises a monomeric cyclosiloxane having the general formula (R ¹ R ² SiO ₂ ) _x , and when R ¹ and R ² are methyl groups, the monomeric cyclosiloxane is D ₃ , D ₄ , D ₅ , D ₆ , D ₇ , D ₈ , D ₉ , and / or D ₁₀ . In these embodiments, the number following the letter D is also a particular monomeric represents a number of -Si (CH _{3) 2} O- repeat units in the cyclosiloxanes, the letter D represents a self-Si (CH _{3) 2} O- unit . As introduced above, monomeric cyclosiloxanes may include substituted or unsubstituted hydrocarbyl groups other than methyl groups. In these embodiments, there are other abbreviations commonly used in the art. By way of example only, when monomeric cyclosiloxanes contain three silicon atoms, and when two of these silicon atoms contain a silicon-bonded methyl group and the third silicon atom comprises a silicon-bonded phenyl group, the monomeric The cyclosiloxane may be referred to as D ₂ P, or D ₂ Ph, wherein D ₂ indicates that _two of these silicon atoms have a silicon-bonded methyl group, and P or Ph indicates that the third silicon atom is silicon-bonded Phenyl group.

In general, monomeric cyclosiloxanes contain from 3 to 6 silicon atoms, such that the subscript x is typically 3 to 6 in the general formula given above for the monomeric cyclosiloxanes. Thus, when R ¹ and R ² are methyl groups, the monomeric cyclosiloxane is generally selected from D ₃ , D ₄ , D ₅ , and / or D ₆ . There are a number of monomeric cyclosiloxanes having various R < ¹ > and R < ² > groups and having 3 to 6 silicon atoms, which are not mentioned here in full. In embodiments where the monomeric cyclosiloxane is D ₃ , D ₄ , D ₅ , and / or D ₆ and R ¹ and R ² are methyl, the monomeric cyclosiloxane is alternatively replaced by hexamethylcyclotrisiloxane (D ₃ ) , Octamethylcyclotetrasiloxane (D ₄ ), decamethylcyclopentasiloxane (D ₅ ), and dodecamethylcyclohexasiloxane (D ₆ ).

In embodiments where the silicone composition comprises a monomeric cyclosiloxane, the monomeric cyclosiloxane is typically present in an amount of at least 80 wt%, alternatively at least 85 wt%, alternatively at least 90 wt%, based on the total weight of the silicone composition, Alternatively greater than or equal to 95 wt%, alternatively greater than or equal to 99 wt%. The amount of monomeric cyclosiloxane present in the silicone composition may deviate from the ranges recited above depending on whether the silicone composition comprises a solvent or other various additive components or compounds.

In embodiments where the silicone composition comprises a monomeric cyclosiloxane, the silicone composition typically further comprises a polymerization catalyst. The monomeric cyclosiloxane may undergo ring-opening polymerization, and the polymerization catalyst may be any polymerization catalyst suitable for promoting the ring opening polymerization of the monomeric cyclosiloxane. Such polymerization catalysts are well known in the art.

The ring-opening polymerization of the monomeric cyclosiloxane may be anionic or cationic. Anionic ring-opening polymerization of monomeric cyclosiloxanes is typically initiated by an inorganic or organic base. Specific examples of polymerization catalysts for anionic ring-opening polymerization of monomeric cyclosiloxanes are silanolate compounds and metal hydroxides, such as alkali metal hydroxides. Cationic ring opening polymerization of monomeric cyclosiloxanes is typically initiated by a benign asset or a benign asset associated with a benign asset, such as a Lewis acid, in combination with another acid or compound. Specific examples of the polymerization catalyst for the cationic ring-opening polymerization of the monomeric cyclosiloxane are H ₂ SO ₄ , CF ₃ SO ₃ H, HClO ₄ , CH ₃ SO ₃ H and the like.

In some embodiments, the polymerization catalyst comprises a phosphazene base. Generally, any ionic or non-ionic phosphazene base is suitable for the purpose of the polymerization catalyst. Specific examples of phosphazene bases suitable for ring-opening polymerization of cyclosiloxanes include those described in U.S. Patent Nos. 5,883,215, 6,284,859, 6,353,075, and 6,448,196, all of which are incorporated herein by reference in their entirety.

The phosphazene base generally comprises the following core structure P = N-P = N, wherein the free N atomic valence is connected to hydrogen or a hydrocarbon, i. E. An amino group, and the free P valence is connected to the amino group. Phosphazene bases and their synthetic routes are described in the literature, for example in Schwesinger et al., Liebigs Ann. 1996, 1055-1081. Phosphazene bases are available from a variety of sources and suppliers.

The nonionic phosphazene base typically has at least three phosphorus atoms per molecule. The phosphazene base may have the general formula:

(R ³ ₂ N) ₃ P = N-) _y (R ³ ₂ N) _3-y P = NR ⁴

Wherein R ³ is independently selected from a hydrogen atom and a substituted or unsubstituted hydrocarbyl group, R ⁴ is selected from a hydrogen atom and a substituted or unsubstituted hydrocarbyl group, y is 1, 2 or 3, Typically 2 or 3. Suitable examples of substituted and unsubstituted hydrocarbyl groups are mentioned above with respect to R < ¹ > and R < ² >. In the structure of the non-ionic phosphazene base, two R < ³ > groups bonded to the same N atom may be connected to complete a heterocyclic ring, such as a 5 or 6 membered ring. In some embodiments, R ³ is a methyl group, R ⁴ is a tertiary butyl group or a tertiary octyl group, and y is 3.

The ionic phosphazene base typically has one of the following general formulas:

(R ³ ₂ N) ₃ P = N--) _{y '} (R ³ ₂ N) _3-y' P - N (H) R ⁴ } ⁺ {A ^- };

{((R ³ ₂ N) ₃ P = N--) _{y "} (R ³ ₂ N) _4-y" P} ⁺ {A ^- }; or

Wherein R ³ and R ⁴ are as defined above, y is a 'is 1, 2 or 3, y''is a is 1, 2, 3 or 4, y''' 1 to 10, A ^- is It is an anion. In the above structure of the ionic phosphazene base, two R ³ groups bonded to the same N atom may be connected to complete a heterocyclic ring such as a 5-membered or 6-membered ring.

Phosphazene bases can be provided, obtained, or prepared in various forms. For example, the phosphazene base may be diluted in a hydrocarbon solvent, such as hexane or heptane, or dispersed in a silicone fluid, such as a polydiorganosiloxane. The solvent can be removed by evaporation under vacuum, and the catalyst can be dispersed in the silicone fluid to provide a stable clear solution. The phosphazene base may alternatively be dissolved in water, or the phosphazene base may be provided in the absence of a solvent or other carrier.

The polymerization catalyst is present in the silicone composition in a catalytically effective amount. The phosphazene base can generally be present in the silicone composition in a relatively low proportion, for example 2 to 200 ppm by weight, based on the total weight of the monomeric cyclosiloxane. This amount is solely for the phosphazene base itself, irrespective of any solvent or other carrier to which the phosphazene base may be placed. As will be readily appreciated in the art, the amount of polymerization catalyst employed will depend on many factors, such as the desired rate of ring opening polymerization of the monomeric cyclosiloxane.

In certain embodiments in which the silicone composition comprises a monomeric cyclosiloxane, the silicone composition further comprises a branching agent. The ring-opening polymerization of monomeric cyclosiloxanes generally results in linear organopolysiloxanes. As such, a branching agent may be used in the silicone composition, which reacts during the ring-opening polymerization of the monomeric cyclosiloxane to impart branching within the encapsulant layer 12 formed in the silicone composition. The branching agent may also impart a three-dimensional crosslinked network to the encapsulant layer 12 formed from the silicon composition. To this end, the branching agent typically comprises a trifunctional or tetrafunctional compound, such as a trifunctional or a tetrafunctional alkoxysilane.

The branching agent may have the general formula:

Si (OR ⁵ ) _z R ⁶ _4-z

Wherein R ⁵ is independently selected from monovalent hydrocarbon groups having 1 to 4 carbon atoms and R ⁶ is independently selected from substituted or unsubstituted hydrocarbyl groups having 1 to 10 carbon atoms and z is 3 or 4. Specific examples of hydrocarbyl groups suitable for R < ⁵ > and R < ⁶ > include those mentioned above for R < ¹ > and R < ² >. One particular example of a branching agent particularly suitable for silicone compositions is tetraethoxysilane, which is also referred to as tetraethyl orthosilicate, or TEOS.

Alternatively or in addition to the general formulas above, the branching agent may comprise a silicone resin. One specific example of a silicone resin suitable for the purpose of the branching agent is an MQ resin. The MQ resin comprises M units, i.e., RSiO _3/2 units, where R may be independently selected substituted or unsubstituted hydrocarbyl or hydroxy groups, and Q units, i.e., SiO _4/2 units . The M and Q units may be present in the MQ resin at various molar ratios depending on the desired molecular weight of the MQ resin. The M and Q units may be present in the MQ resin in a ratio ranging from 4: 1 to 0.7: 1. The MQ resin typically has a molecular weight of less than 20,000, which decreases as the ratio of M units to Q units increases.

When used in silicone compositions with monomeric cyclosiloxanes, the branching agent is generally present in the silicone composition in an amount of up to 10 weight percent, based on the total weight of the silicone composition. The amount of branching agent present in the silicone composition may deviate from the ranges recited above depending on whether the silicone composition comprises a solvent or other various additive components or compounds.

In various embodiments in which the silicone composition comprises a monomeric cyclosiloxane, the silicone composition further comprises chain termination. Chain termination generally provides at least one M unit, i.e. R ⁷ ₃ SiO _1/2 units, wherein R ⁷ is typically a hydrocarbyl group. The M units terminate the polymer chain to prevent further chain groups and / or polymerization at that location. Accordingly, the chain termination can be employed in the silicone composition to selectively control the kinematic viscosity and / or degree of polymerization of the encapsulant layer 12 formed of the silicone composition.

In one embodiment, the chain termination has the following average formula:

Wherein Z is a halogen atom, an alkoxy group having 1 to 10 carbons, or a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms; R ⁸ , R ⁹ , and R ¹⁰ are each independently substituted or unsubstituted hydrocarbyl groups having 1 to 10 carbon atoms; X is O or NH, and y is in the range of 0 to 1.

The chain termination may be, for example, silane, siloxane, or silazane. Suitable silanes include, for example, triorganosilanes such as halo-, alkoxy-, and carboxy-triorganosilanes. Specific examples of the silane or silazane chain termination are trimethylchlorosilane, trimethylmethoxysilane, hexamethyldisiloxane, diphenylmethylmethoxysilane, dimethylphenylmethoxysilane, diphenylmethylchlorosilane, dimethylphenylchlorosilane , Hexamethyldisilazane, tetramethyldivinyldisiloxane, and hydrolyzates thereof. One specific example of a siloxane suitable for the purpose of chain termination is a trimethyl end-blocked polydimethylsiloxane. The chain termination may be included in the silicone composition prior to placing the silicone composition between the photovoltaic cell layer 14 and the outer layer 16. Alternatively, the chain termination can be accomplished by placing the photovoltaic cell layer 14 and the outer layer 16 during the polymerization of the silicone composition, i. E. After placing the silicone composition between the photovoltaic cell layer 14 and the outer layer 16, As shown in FIG. Chain termination is typically used in amounts of from greater than 0 to 20 percent by weight based on the total weight of the silicone composition. The amount of chain terminator present in the silicone composition may deviate from the ranges recited above depending on whether the silicone composition comprises a solvent or other various additive components or compounds.

In the embodiments described above wherein the silicone composition comprises a monomeric cyclosiloxane, the silicone composition may further comprise other various components such as solvents, thixotropic agents, fillers, organopolysiloxane fluids, and the like. Silicone compositions comprising monomeric cyclosiloxanes can be of no use, i. E. Substantially free of solvents other than any solvent that can be provided with the polymerization catalyst. For the purposes of the present invention, the components described herein, for example, monomeric cyclosiloxanes, polymerization catalysts, and branching agents, can be prepared by reacting a solvent Do not configure. Silicone compositions typically lack conventional solvents, such as water, aliphatic and aromatic hydrocarbons, alcohols, and the like. In other words, the solvent is typically not included in the silicone composition as a separate component.

As introduced above, in certain embodiments, the silicone composition further comprises a filler. The filler may be coated with a fluorescent material. Alternatively, the fluorescent material can be dissolved in the filler. The fluorescent material may be fluorescent, luminescent, or phosphorescent.

Fluorescent, luminescent, or phosphorescent materials can absorb light within the blue or UV range and emit visible light. Thus, in some embodiments, the fluorescent material absorbs blue light and / or ultraviolet light, and the fluorescent material emits visible light and / or infrared light. Phosphors that may also be referred to as phosphors typically include suitable host materials and activator materials. The host material is typically an oxide, sulfide, selenide, halide, or silicate of zinc, cadmium, manganese, aluminum, silicon, or various rare earth metals. The activator is added to prolong the release time.

Exemplary phosphors are copper-activated zinc sulfide (ZnS: Cu) and silver-activated zinc sulfide (ZnS: Ag). Exemplary other phosphors include strontium titanium (SrTiO ₃ : Pr, Al) activated by zinc sulfide and cadmium sulfide (ZnS: CdS), europium activated strontium aluminate (SrAlO ₃ : Eu), praseodymium and aluminum, (Ca, Sr) S: Bi) with strontium sulfide with bismuth, copper and magnesium activated zinc sulfide (ZnS: Cu, Mg), or any combination thereof.

The method of the present invention further comprises the step of polymerizing the silicone composition at a location between the photovolariic cell layer 14 and the outer layer 16 to form the encapsulant layer 12 in the photovolatile battery module 10 . The step of polymerizing the silicone composition may vary depending on the silicone composition employed. Generally, the photovoltaic cell layer 14 and the outer layer 16 are exposed at a slightly elevated temperature such that a high temperature (e.g., greater than 100 ° C) or other polymerization technique, such as radiation, need not be applied, It is preferable to polymerize the silicone composition at the original position between the battery layer 14 and the outer layer 16. The polymerization of the silicone composition is in situ because the silicone composition is disposed between the photovoltaic cell layer 14 and the outer layer 16 during the polymerization of the silicone composition.

The polymerization of the monomeric cyclosiloxane can be carried out in the presence of water, a silanol or an alcohol, or in the absence of any of these compounds. Water is generally not used to initiate the polymerization of the silicone composition, except when the non-ionic phosphazene base is used as the polymerization catalyst. However, when present in the silicone composition, water is typically used in an amount of 0.5 to 10 moles per mole of the polymerization catalyst. If present, silanols, such as trialkylsilanols, or alcohols, such as alcohols having from 1 to 8 carbon atoms, can be used in similar amounts.

In embodiments where the silicone composition comprises a monomeric cyclosiloxane, the polymerization of the silicone composition can be carried out at a wide range of temperatures. For example, the silicone composition can be polymerized at ambient temperature and pressure. Alternatively, the silicone composition can be heated at ambient pressure, but above ambient temperature, such as above ambient temperature to 300 캜, alternatively above ambient temperature to 250 캜, alternatively above ambient temperature to 200 캜, Alternatively from above the ambient temperature to 100 ° C, alternatively above ambient temperature to 80 ° C, alternatively above ambient temperature to 60 ° C. The time for which the silicone composition is polymerized depends on many variables, such as the particular polymerization catalyst employed, the amount of the particular polymerization catalyst employed, and the desired physical properties of the encapsulant layer 12 formed by polymerization of the silicone composition. The time for the silicone composition to polymerize in situ can be from greater than 0 to 504 hours, alternatively from 12 to 336 hours, alternatively from 24 to 168 hours. Generally, the silicone composition is polymerized during at least partial exposure to ambient air, i.e., the silicone composition is typically not completely enclosed during the step of polymerizing the silicone composition. The polymerization of the silicone composition can be supplemented by an additional curing methodology, such as gamma-radiation.

The encapsulant layer 12 formed from a silicone composition comprising a monomeric cyclosiloxane is generally referred to as gum. The cross-linking density and dynamic density of the encapsulant layer 12 depends on many factors including the presence or absence of a branching agent as well as the parameters (e.g., temperature, time, etc.) with which the silicone composition is cured. Typically, the encapsulant layer 12 formed of a silicone composition when the silicone composition comprises a monomeric cyclosiloxane has a dynamic viscosity of at least 50 centipoise (or mPa · s), alternatively at least 1,000 centipoise, Alternatively greater than 10,000 centipoise, alternatively greater than 100,000 centipoise.

Regardless of the particular silicone composition employed in the present process, the encapsulant layer 12 formed from the silicone composition is substantially transparent, allowing sunlight containing ultraviolet light to substantially pass through the encapsulant layer 12. [ In particular, the encapsulant layer 12 has a light transmittance of at least 70% when determined using UV / Vis spectrophotometry using ASTM E424-71. In one embodiment, the encapsulant layer 12 has a light transmittance of 80% or greater. In an alternative embodiment, the encapsulant layer 12 has a light transmittance of 90% or greater. In yet another embodiment, the encapsulant layer 12 has a light transmittance of approximately 100%.

As described above, the silicone composition is disposed between the photovoltaic cell layer 14 and the outer layer 16 and is polymerized at its original location. Photovoltaic cell layer 14 and outer layer 16 are common layers of photovoltaic cell modules. Similarly, the photovoltaic cell layer 14 may be any photovoltaic cell layer known to those skilled in the art for the photovoltaic cell module. The photovoltaic cell layer 14 may be any photovoltaic cell layer known to those skilled in the art for the photovoltaic cell module. have.

In particular, the outer layer 16 is substantially transparent, allowing sunlight containing ultraviolet light to substantially pass through the outer layer 16. The outer layer 16 has a light transmittance of at least 70% when determined using UV / Vis spectrophotometry using ASTM E424-71. In one embodiment, the outer layer 16 has a light transmittance of at least 80%. In an alternative embodiment, the outer layer 16 has a light transmittance of 90% or greater. In yet another embodiment, the outer layer 16 has a light transmittance of approximately 100%.

In some embodiments, outer layer 16 and encapsulant layer 12 have similar refractive index values. In particular, the outer layer 16 and the encapsulant layer 12 have a refractive index value within 0.1, alternatively within 0.08, alternatively within 0.06, alternatively within 0.04, alternatively within 0.02, alternatively within 0.01 Respectively.

The outer layer 16 is typically rigid and stiff. Alternatively, the outer layer 16 may include both rigid and rigid segments and at the same time soft and flexible segments. In one embodiment, the outer layer 16 comprises glass. The glass can be, for example, soda lime glass. In another embodiment, the outer layer 16 comprises a polymer. This polymer is a polyimide; Acrylics such as polymethylmethacrylate; Polycarbonate; Ethylene-vinyl acetate copolymer; Fluoropolymers such as ethylene tetrafluoroethylene and polyvinyl fluoride; Polyalkylene terephthalates such as polyethylene terephthalate or polybutylene terephthalate; And combinations thereof. However, the present invention is not limited thereto. Such polymers may be coated with silicon and oxygen-based materials (SiO _x ).

The photovoltaic cell layer 14 is for converting light energy into electricity through photovoltaic effect. Specifically, the photovoltaic cell layer 14 includes a photovoltaic cell for converting light energy into electricity. The photovoltaic cell may comprise a single-layer, single-crystal p-n junction diode. These photovoltaic cells are typically fabricated using a diffusion process with a silicon wafer. Alternatively, the photovoltaic cell may comprise a thin epitaxial deposit of a (silicon) semiconductor on a lattice-matched wafer. In this embodiment, the photovoltaic cell layer 14 can be classified as space or terrestrial, and typically has an AMO efficiency of 7 to 40%. The photovoltaic cell may also include a quantum well device, such as a quantum dot, a quantum rope, and the like, and may also include carbon nanotubes. Without being bound by any particular theory, it is believed that these types of photovoltaic cells can have a maximum production efficiency of 45% AM0. Still further, photovoltaic cells may comprise a mixture of polymer and nanoparticles forming a single multi-spectral layer that can be laminated to make the multi-spectral solar cell more efficient and less expensive.

Alternatively, the photovoltaic cell of the photovoltaic cell layer may comprise a CIS based solar absorber layer comprising copper, indium, and selenium. In some embodiments in which the photovoltaic cell comprises a CIS based solar absorber layer, the CIS based solar absorber layer further comprises a metal selected from the group of gallium, aluminum, boron, tellurium, sulfur, and combinations thereof can do.

Specific examples of photovoltaic cells of photovoltaic cell layer 14 include, but are not limited to, amorphous silicon, monocrystalline silicon, polycrystalline silicon, microcrystalline silicon, nanocrystalline silica, cadmium telluride, Copper indium / gallium selenide / sulfide (CIGS), gallium arsenide, polyphenylene vinylene, copper phthalocyanine, carbon fullerene, and combinations thereof. Photovoltaic cell layer 14 may also include a light absorbing dye, such as a ruthenium organometallic dye. In some embodiments, photovoltaic cell layer 14 comprises monocrystalline and / or polycrystalline silicon. In another embodiment, the photovoltaic cell layer 14 comprises copper indium / gallium selenide / sulfide (CIGS).

The photovoltaic cell layer 14 may further include a support layer for providing rigidity to the photovoltaic cell. For example, a photovoltaic cell may be disposed on the support layer to provide a photovoltaic cell layer 14, which has increased stiffness compared to the photovoltaic cell itself. The support layer may comprise the same material as the outer layer 16 or a different material than the outer layer 16.

The photovoltaic cell layer 14 may have a first shape extending between a first end and a second end and the outer layer 16 may have a second shape extending substantially parallel to the first shape of the photovoltaic cell layer 14, Shape. As shown in FIG. 2, the first and second shapes of the photovoltaic cell layer 14 and the outer layer 16, respectively, may be cylindrical. In these embodiments, the photovoltaic cell layer 14 has an inner diameter and an outer diameter, and the outer layer 16 has an inner diameter and an outer diameter. The inner diameter of the outer layer 16 is generally larger than the outer diameter of the photovoltaic cell layer 14 so that when the photovoltaic cell layer 14 is disposed in the outer layer 16, (16) are concentric cylinders defining a space between them for forming the encapsulant layer (12), as shown in Fig. In these embodiments, the difference between the outer diameter of the photovoltaic cell layer 14 and the inner diameter of the outer layer 16 defines the thickness of the encapsulant layer 12 formed of the silicone composition. Specifically, half of the difference between the outer diameter of the photovoltaic cell layer 14 and the inner diameter of the outer layer 16 is equivalent to the thickness of the sealing material layer 12. Generally, the thickness of the encapsulant layer 12 is greater than 0 to 3 mm, alternatively 1 to 2.5 mm, alternatively 1.75 to 2.25 mm. The inner diameter and the outer diameter of the photovoltaic cell layer 14 and the outer layer 16 may vary depending on a desired size of the photovoltaic module 10. The first and second shapes of the photovoltaic cell layer 14 and the outer layer 16 may be other than cylindrical shapes without departing from the scope of the present invention. For example, the first and second shapes of the photovoltaic cell layer 14 and the outer layer 16 may be rectangular, octagonal, elliptical, or the like. In addition, the first and second shapes of the photovoltaic cell layer 14 and the outer layer 16 may not be substantially the same as each other. For example, the first shape of the photovoltaic cell layer 14 may be rectangular, while the second shape of the outer layer 16 may be cylindrical. In this embodiment, the encapsulant layer 12 has a non-uniform thickness.

The photovoltaic cell module 10 further includes a base layer for bonding the outer layer 16 and the photovoltaic cell layer 14. [ Specifically, the base layer is typically bonded to the lower portion of the outer layer 16 and the photovoltaic cell layer 14 such that the silicone composition is exposed to the photovoltaic module 10 ) Between the base layer and the photovoltaic cell layer 14. The base layer includes any suitable material for preventing the silicone composition from leaking out between the outer layer 16 and the photovoltaic cell layer 14 before polymerizing the silicone composition to form the encapsulant layer 12 can do. Similarly, the photovoltaic cell module 10 generally includes an upper layer disposed on the opposite side of the base layer, i. E., Disposed on top of the photovoltaic battery module 10, between the upper layer and the base layer, (12) between the photovoltaic cell layer (16) and the photovoltaic cell layer (14). The top layer may be the same as or different from the base layer. The top layer may be disposed on top of the photovoltaic module 10 before or after polymerizing the silicone composition. Typically, the top layer is placed on top of the photovoltaic module 10 after the silicone composition is polymerized such that the silicone composition is polymerized while at least partially exposed to ambient air, as introduced above. In embodiments where the silicone composition comprises a branching agent, the branching agent may react prior to reacting with components of the silicone composition, or at the same time while reacting with components of the silicone composition, upon contact with ambient moisture, Can be hydrolyzed.

A specific example of the manufacture and construction of a cylindrical photovoltaic module is disclosed in U.S. Published Patent Application 2009/0014055, which is incorporated herein by reference in its entirety. This application discloses various components that are generally included within such cylindrical photovolatile battery modules, which are not explicitly described herein. In particular, this application discloses the construction of photovoltaic cell layers as well as various aspects of the electrical connections and electrodes of the cylindrical photovoltaic module.

Once the encapsulant layer 12 is polymerized at the original position between the photovolariable cell layer 14 and the outer layer 16, the photovoltaic module 10 formed therefrom can be used. For example, as is readily understood in the art, the photovoltaic battery module 10 may be used individually or the photovoltaic battery module 10 may be used as an array having a plurality of photovoltaic cell modules . The encapsulant layer 12 is generally encapsulated by the photovoltaic module 10 in a manner similar to the encapsulant layer 12 formed by the silicone composition so that the outer layer 16 is damaged during use of the photovolatile battery module 10. [ , Such leakage or escape may adversely affect the output and efficiency of the photovoltaic module 10.

One or more of the above values may be varied by ± 5%, ± 10%, ± 15%, ± 20%, ± 25%, etc., as long as the variation is within the scope of the present invention. Unexpected results can be obtained from each element of the Markush group independently of all other elements. The respective elements may be used individually and / or in combination and provide adequate support for specific embodiments within the scope of the appended claims. The subject matter of all combinations of independent terms and dependent terms (both single dependent terms and multiple dependent terms) is expressly contemplated herein. This disclosure is exemplary only, including descriptive terms, rather than limiting. Many modifications and variations of the present invention are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described herein.

The following examples illustrate the invention and do not limit the scope of the invention.

Various silicone compositions are prepared according to the present invention. In particular, 19 silicone compositions comprising at least one monomeric cyclosiloxane are prepared. Tables 1 and 2 show the relative amounts of various components and various components in the 19 silicone compositions.

Branching agent 1 comprises tetraethylorthosilicate.

Branching agent 2 comprises tetrakis (dimethylvinylsiloxy) silane. Polymerization catalyst 1 comprises an ionic phosphazene base catalyst.

In order to simulate a cylindrical photovoltaic cell module, a glass test tube is placed in an inverted state in a glass cylinder. The glass cylinder has an inner diameter of 26.6 mm. The glass test tube has an outer diameter of 24.9 mm. The glass cylinder represents the outer layer of the photovoltaic cell module, and the glass test tube represents the photovoltaic cell layer of the photovoltaic cell module.

Each of the 19 silicone compositions is placed in a glass cylinder to form an encapsulant layer between each glass cylinder and the glass test tube. Each of the encapsulant layers has a diameter of 0.85 mm. The encapsulant layer was cured according to the parameters in Tables 3 and 4 below. The viscosity of each sealing layer was measured. The fluid viscosity of these encapsulant layers was measured at 25 占 폚 via a Brookfield rheometer. The viscosity of these sealant layers was measured via a biaxial conical flow meter at 30 C, 1.667 Hz and 13.95% strain. The viscosity of the encapsulant layer was measured at specific intervals to show a change in kinematic viscosity with time, that is, with formation of the encapsulant layer by polymerization of the silicone composition. In addition, the appearance of the encapsulant layer was visually inspected to determine the degree of transparency. In the following Tables 3 and 4, "transparent" indicates that the specific encapsulant layer was substantially transparent, i.e., not turbid or hazy at the time of visual inspection. Conversely, "turbidity" indicates that the particular encapsulant layer is translucent or otherwise not substantially transparent. When the preferred viscosity was obtained after 7 days (as in Tests 3 to 5, for example), no further tests of physical properties were performed after 14 days, as shown in Table 3 below. Initial cure parameters for each test are listed in the second column of Table 3. After 7 days, the polymerization at the original position continues at ambient conditions, even for those tests where the initial curing parameters comprise a temperature above room temperature (e.g. 40 ° C).

It is to be understood that the invention has been described in an illustrative manner, and that the terminology used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The present invention may be practiced otherwise than specifically described.

Claims (20)

A method of forming an encapsulant layer for a photovoltaic module comprising a photovoltaic cell layer and an outer layer spaced from the photovoltaic cell layer, the method comprising:
Placing the silicone composition is less than between the photovoltaic cell layer and the outer layer, having a kinematic viscosity (kinematic viscosity) is greater than 0 to about 0.001 m ² / s (1,000 centistokes (cSt)) at 25 ℃; And
Polymerizing the silicone composition in situ between the photovoltaic cell layer and the outer layer to form the encapsulant layer in the photovolariic battery module. The method of claim 1, wherein the silicone composition has a kinematic viscosity at 25 ℃ 0 than to about ^{0.0003 m 2 / s (300 cSt} ) less than about. According to claim 1 or 2 wherein said silicone composition is the kinematic viscosity is more than 0 at 25 ℃ to about ^{0.0001 m 2 / s (100 cSt} ) less than about. 4. The method of any one of claims 1 to 3, wherein the silicone composition comprises at least one monomeric cyclosiloxane. 5. The composition of claim 4, wherein the at least one monomeric cyclosiloxane has the general formula (R ¹ R ² SiO ₂ ) _x , wherein R ¹ and R ² are substituted or unsubstituted hydrocarbons having 1 to 10 carbon atoms X is an integer from 3 to 10. < RTI ID = 0.0 > 11. < / RTI > The method of claim 4, wherein the at least one monomeric cyclosiloxanes are hexamethylcyclotrisiloxane cycloalkyl-trimethyl siloxane (D _3), octamethylcyclotetrasiloxane (D _4), decamethylcyclopentasiloxane (D _5), and dodeca-methyl cyclohexanone siloxane, the method comprising at least one of (D _6). 7. The method of any one of claims 4 to 6, wherein the silicone composition further comprises a catalytically effective amount of a polymerization catalyst. 8. The method of claim 7, wherein the polymerization catalyst comprises a phosphazene base. 9. The method of claim 8, wherein the phosphazene base is
((R ³ ₂ N) ₃ P = N-) _y (R ³ ₂ N) _{3 -y} P = NR ⁴ ;
(R ³ ₂ N) ₃ P = N--) _{y '} (R ³ ₂ N) _3-y' P - N (H) R ⁴ } ⁺ {A ^- };
{((R ³ ₂ N) ₃ P = N--) _{y "} (R ³ ₂ N) _4-y" P} ⁺ {A ^- }; And

And < RTI ID = 0.0 >
Wherein R ³ is independently selected from a hydrogen atom and a substituted or unsubstituted hydrocarbyl group ring, the two R ³ groups are connected to bind to the same N atom may complete a heterocyclic ring, R ⁴ is hydrogen 2 or 3, y 'is 1,2 or 3, y "is 1,2,3 or 4, and y''is selected from substituted or unsubstituted hydrocarbyl groups, 'Is 1 to 10, and A ^- is an anion. 10. The method according to any one of claims 4 to 9, wherein the silicone composition further comprises a branching agent. 11. The method of claim 10,
Si (OR ⁵ ) _z R ⁶ _4-z ,
Wherein R ⁵ is independently selected from monovalent hydrocarbon groups having 1 to 4 carbon atoms and R ⁶ is independently selected from substituted or unsubstituted hydrocarbyl groups having 1 to 10 carbon atoms and z is 3 or 4. < / RTI > 12. The silicone composition according to any one of claims 4 to 11,

Lt; RTI ID = 0.0 > a < / RTI > chain termination,
Wherein Z is a halogen atom, an alkoxy group having 1 to 10 carbons, or a substituted or unsubstituted hydrocarbyl group having 1 to 10 carbon atoms; R ⁸ , R ⁹ , and R ¹⁰ are each independently substituted or unsubstituted hydrocarbyl groups having 1 to 10 carbon atoms; X is O or NH, and y is in the range of 0 to 1. 13. The photovoltaic cell layer according to any one of claims 1 to 12, wherein the photovolastically cell layer has an inner diameter and an outer diameter, the outer layer has an inner diameter and an outer diameter, Said inner diameter and outer diameter being greater than said inner diameter and said outer diameter. 14. The method according to any one of claims 1 to 13, wherein the photovolariic cell layer and the outer layer are cylindrical. 15. The method according to any one of claims 1 to 14, wherein the photovoltaic cell layer comprises copper indium gallium di-selenide. 16. The method according to any one of claims 1 to 15, wherein the outer layer is substantially transparent. 17. The method according to any one of claims 1 to 16, wherein the outer layer comprises glass. 18. The method of any one of claims 1 to 17, wherein the encapsulant layer formed from the silicone composition is substantially transparent. 19. The method according to any one of claims 1 to 18, wherein the silicone composition is solvent-free. And an outer diameter of the outer layer is larger than an inner diameter of the photovoltaic cell layer as an inner diameter and an outer diameter of the photovoltaic cell layer. A method of forming an encapsulant layer for a cylindrical photovolatile battery module, further comprising the outer layer having an inner diameter and an outer diameter, the method comprising:
Placing the silicone composition is less than between the photovoltaic cell layer and the outer layer, the dynamic viscosity is from greater than 0 to about 0.001 m ² / s (1,000 centistokes (cSt)) at 25 ℃; And
Polymerizing said silicone composition at a location between said photovolariic cell layer and said outer layer to form said encapsulant layer in said cylindrical photovolariic module.

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