WO2013112874A1 - A photovoltaic cell module and method of forming the same - Google Patents

A photovoltaic cell module and method of forming the same Download PDF

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Publication number
WO2013112874A1
WO2013112874A1 PCT/US2013/023197 US2013023197W WO2013112874A1 WO 2013112874 A1 WO2013112874 A1 WO 2013112874A1 US 2013023197 W US2013023197 W US 2013023197W WO 2013112874 A1 WO2013112874 A1 WO 2013112874A1
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WIPO (PCT)
Prior art keywords
polymeric
substrate
polymeric strip
cell
front face
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PCT/US2013/023197
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French (fr)
Inventor
Barry M. KETOLA
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Dow Silicones Corp
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Dow Corning Corp
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
    • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
    • B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
    • B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
    • B32B17/10009—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the number, the constitution or treatment of glass sheets
    • B32B17/10036—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the number, the constitution or treatment of glass sheets comprising two outer glass sheets
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F19/00—Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules
    • H10F19/80—Encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells
    • H10F19/804—Materials of encapsulations
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F19/00—Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules
    • H10F19/90—Structures for connecting between photovoltaic cells, e.g. interconnections or insulating spacers
    • H10F19/902—Structures for connecting between photovoltaic cells, e.g. interconnections or insulating spacers for series or parallel connection of photovoltaic cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • Solar or PV cells are semiconductor devices used to convert light into electricity.
  • the PV cells are encapsulated by an encapsulant to form PV cell modules.
  • the modules typically include a cover sheet (or “superstrate”) and a back sheet (or “substrate”), such that the PV cells and encapsulant are sandwiched between the cover sheet and substrate.
  • the PV cells are operatively connected to one another with tabbing ribbon.
  • the encapsulant and cover sheet protect the PV cells from environmental factors, such as wind, dirt, and rain.
  • a common encapsulant is ethyl vinyl acetate (EVA) and another is silicone. EVA has one or more drawbacks, such as low UV resistance, degradation over time, discoloration over time, etc.
  • the present invention provides a photovoltaic (PV) cell module.
  • the invention module comprises a substrate having a front face and a rear face spaced from the front face of the substrate.
  • the module also comprises a cover sheet having a front face and a rear face spaced from the front face of the cover sheet.
  • At least one PV cell is disposed between the substrate and the cover sheet.
  • the PV cell has a front face and a rear face spaced from the front face of the PV cell.
  • At least one tabbing ribbon is disposed on the rear face of the PV cell.
  • At least one polymeric strip is disposed between the substrate and the PV cell adjacent the tabbing ribbon for protecting the tabbing ribbon from the front face of the substrate.
  • the polymeric strip is formed from a first polymeric composition.
  • a tie- layer is disposed between the substrate and the cover sheet and around the PV cell for coupling the rear face of the cover sheet to the front face of the substrate and for coupling the front face of the PV cell to the rear face of the cover sheet.
  • the tie-layer is formed from a second polymeric composition different than the first polymeric composition of the polymeric strip.
  • the present invention also provides a method of forming the invention module.
  • the invention method comprises the step of applying the first polymeric composition on i) the front face of the substrate and/or ii) the rear face of the PV cell to form the polymeric strip on the front face of the substrate and/or the rear face of the PV cell in an uncured state.
  • the method further comprises the step of applying the second polymeric composition on the ii) rear face of the cover sheet to form the tie-layer in an uncured state.
  • the method further comprises the step of disposing the PV cell on the tie-layer such that the rear face of the PV cell is disposed opposite the cover sheet.
  • the method further comprises the step of combining the substrate and the cover sheet to form the module such that the tie-layer is sandwiched between the cover sheet and the substrate and the polymeric strip is disposed adjacent the tabbing ribbon for protecting the tabbing ribbon from the front face of the substrate.
  • the module may be used for various applications, such as for converting light of many different wavelengths into electricity.
  • FIG. 1 is perspective view of a pair of photovoltaic (PV) arrays each including an embodiment of PV cell modules;
  • FIG. 2 is a broken cross-sectional side-view of an embodiment of the PV cell module including a cover sheet, a substrate, a PV cell, tabbing ribbon, a tie-layer, and polymeric strips;
  • FIG. 4 is a broken cross-sectional side-view of another embodiment of the PV cell module
  • FIG. 5 is a broken cross-sectional side-view of another embodiment of the PV cell module
  • FIG. 6 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of a method suitable to form the PV cell module of FIG. 4;
  • FIG. 7 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of a method suitable to form the PV cell module of FIG. 5;
  • FIG. 8 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of a method suitable to form the PV cell module of FIG. 3.
  • PV cell module 20 a photovoltaic (PV) cell module formed in accordance with the invention method is shown generally at 20.
  • the PV cell module 20 is hereinafter referred to as the module 20.
  • the components of the invention module 20 are not necessarily drawn to scale in the figures, such that they may be larger or smaller than that which is depicted.
  • a plurality of modules 20 is connected to form a pair of arrays 22.
  • the arrays 22 may be planar or non-planar. While shown in this configuration/arrangement, the module 20 may be used alone or in a group of two or more (e.g., as shown in FIG. 1 ), and may be used for various applications, such as for structures, buildings, vehicles, devices, etc.
  • the present invention is not limited to any particular configuration or use of the modules 20 or arrays 22.
  • the modules 20 can be used to convert light energy into electrical energy.
  • the module 20 comprises a substrate 24.
  • the substrate 24 has a front face 26 and a rear face 28 spaced from the front face 26.
  • the substrate 24 may be substantially planar or non-planar.
  • the substrate 24 may also be referred to in the art as a backsheet 24.
  • the substrate 24 is useful for providing support, protection, and/or an interface for the module 20.
  • the substrate 24 can be formed from various materials. Examples of suitable materials include glass, polymeric materials, composite materials, etc.
  • the substrate 24 can be formed from glass, polyethylene terephthalate (PET), thermoplastic elastomer (TPE), polyvinyl fluoride (PVF), silicone, etc.
  • the substrate 24 may be formed from a combination of different materials, e.g. a polymeric material and a fibrous material.
  • the substrate 24 may have portions formed from one material, e.g. glass, and other portions formed from another material, e.g. a polymeric material.
  • the substrate 24 can be of various thicknesses, such as from about 0.05 to about 5.0, about 0.1 to about 4, or about 0.125 to about 3.2, millimeters (mm) on average, or any range between the lowest and highest of these values. Thickness of the substrate 24 may be uniform or may vary.
  • suitable substrates 24 include those described in U.S. App. Pub. Nos. 2008/0276983, 201 1/0005066, and 201 1/0061724, and in WO Pub. Nos. 2010/051355 and 2010/141697.
  • suitable substrates 24 include those described as "backsheets" in U.S. Pat. App. Ser. No. 61 /725277 ("the '277 application”; Attorney Docket No. DC1 1521 PSP1 ; 071038.01095).
  • the aforementioned disclosures are hereinafter referred to as the "incorporated references”, which are incorporated herein by reference in their entirety to the extent they do not conflict with the general scope of the present invention.
  • the module 20 further comprises a cover sheet 30.
  • the cover sheet 30 has a front face 32 and a rear face 34 spaced from the front face 32.
  • the cover sheet 30 may be substantially planar or non-planar.
  • the cover sheet 30 is useful for protecting the module 20 from environmental conditions such as rain, snow, dirt, heat, etc.
  • the cover sheet 30 is transparent to UV and/or visible light for gathering light energy. Said another way, the cover sheet 30 is typically optically transparent.
  • the cover sheet 30 is generally the sun side or front side of the module 20.
  • the cover sheet 30 can be formed from various materials. Examples of suitable materials include those described above with the substrate 24. Further examples of suitable cover sheets 30 include those described in the incorporated references.
  • the cover sheet 30 is formed from glass. Various types of glass can be utilized such as silica glass, polymeric glass, etc.
  • the cover sheet 30 may be formed from a combination of different materials.
  • the cover sheet 30 may have portions formed from one material, e.g. glass, and other portions formed from another material, e.g. a polymeric material.
  • the cover sheet 30 may be the same as or different from the substrate 24. For example, both the cover sheet 30 and the substrate 24 may be formed from glass with equal or differing thicknesses. In certain embodiments, both the cover sheet 30 and the substrate 24 are formed from glass.
  • the cover sheet 30 can be of various thicknesses, such as from about 0.5 to about 10, about 1 to about 7.5, about 2.5 to about 5, or about 3, mm on average, or any range between the lowest and highest of these values.
  • the substrate 24 is of a similar or the same thickness as the cover sheet 30, e.g. when both are formed from glass. Thickness of the cover sheet 30 may be uniform or may vary. Further examples of suitable cover sheets 30 include those described in the incorporated references, such as those described as the "superstrates" in the '277 application.
  • the module 20 further comprises at least one PV cell 36, alternatively, a plurality of PV cells 36.
  • the PV cells 36 are disposed between the substrate 24 and the cover sheet 30.
  • the PV cell 36 has a front face 38 and a rear face 40 spaced from the front face 38.
  • the PV cells 36 are typically substantially coplanar with one another.
  • the PV cells 36 can be arranged in various patterns, such as a series of PV cells 36 in a grid-like pattern. The present invention is not limited to any particular pattern.
  • the PV cells 36 may be offset from one another, such as in non-planar module 20 configurations.
  • the PV cells 36 may be of various dimensions, be of various types, and be formed from various materials. Examples of suitable PV cells 36 include those described in the incorporated references. The PV cells 36 may be the same as or different from each other. The PV cells 36 can be of various thicknesses, such as from about 50 to about 250, about 100 to about 225, about 175 to about 225, or about 180, ⁇ on average, or any range between the lowest and highest of these values. The PV cells 36 can also be of various widths and lengths as understood in the art. In certain embodiments, the PV cells 36 may be referred to in the art as crystalline silicon PV cells 36. Further examples of suitable PV cells 36 include those described in the incorporated references, such as those described in the '277 application.
  • Tabbing ribbon 42 is disposed between the PV cells 36.
  • the tabbing ribbon 42 is useful for establishing a circuit in the module 20.
  • the tabbing ribbon 42 typically extends over the faces 38, 40 of the PV cells 36.
  • a series of two or more connected PV cells 36 may be referred to in the art as a string of cells.
  • the tabbing ribbon 42 is only shown on one of the faces 38, 40 merely for the sake of orientation clarity.
  • the tabbing ribbon 42 may be formed from various conductive materials, such as metals, conducting polymers, or combinations thereof. Examples of other suitable materials include those described in the incorporated references.
  • the tabbing ribbon 42 is useful for connecting the PV cells 36 together, as well as to other components such as to bussing (not shown), other modules 20, etc.
  • the PV cells 36 may be connected by the tabbing ribbon 42 in series or in parallel.
  • the tabbing ribbons 42 are typically connected to bussing (not shown) for establishing a circuit and carrying energy collected by the PV cells 36.
  • the tabbing ribbon 42 may be of various shapes and sizes, and may also be referred to in the art as tabbing, bussing, wire, or leads, depending on shape, size, location, etc.
  • the tabbing ribbon 42 can be of various dimensions, such as from about 0.125 to about 2 mm in thickness and/or width on average.
  • At least one polymeric strip 44 is disposed between the substrate 24 and the PV cell 36.
  • the polymeric strip 44 is adjacent the tabbing ribbon 42.
  • the polymeric strip 44 is useful for protecting the tabbing ribbon 42 from the front face 26 of the substrate 24.
  • the module 20 includes a plurality of polymeric strips 44.
  • the module 20 includes a first polymeric strip 44a and a second polymeric strip 44b spaced from the first polymeric strip 44a.
  • the first polymeric strip 44a is typically disposed adjacent the first tabbing ribbon 42a and the second polymeric strip 44b is typically disposed adjacent the second tabbing ribbon 42b.
  • the polymeric strips 44 are formed from a first polymeric composition. As shown generally, the polymeric strips 44 are spaced horizontally and side-by-side. Further, the polymeric strips 44 are generally disposed parallel relative to the direction of the tabbing ribbons 42.
  • the first polymeric composition may be formed from various polymer compositions.
  • the first polymeric composition is a silicone, more typically a silicone elastomer.
  • Suitable silicones include branched and unbranched, more typically unbranched, oligomeric or polymeric organosiloxanes.
  • suitable polymeric compositions include hydrosilylation-reaction, condensation-reaction, and hydrosilylation/condensation- reaction, curable silicone compositions.
  • the polymeric strips 44 are formed from a hydrosilylation- reaction curable silicone composition.
  • the first polymeric composition comprises a diorganopolysiloxane having alkenyl groups (e.g. vinyl groups), an organosilicon hydride having silicon-bonded hydrogen atoms reactive with the alkenyl groups of the diorganopolysiloxane, and a non-reactive organopolysiloxane.
  • non- reactive it is generally meant that the non-reactive organopolysiloxane does not react with the diorganopolysiloxane or the organosilicon hydride.
  • suitable diorganopolysiloxanes, organosilicon hydrides, and non-reactive organopolysiloxanes include those described in the incorporated references.
  • the diorganopolysiloxane and the organosilicon hydride will generally react in the presence of the non-reactive organopolysiloxane, and optionally, additional components, to form a silicone polymer.
  • the non-reactive organopolysiloxane is useful for adjusting physical properties of the silicone polymer as described further below.
  • suitable additive components, such as catalysts include those described in the incorporated references.
  • the diorganopolysiloxane is a dimethylvinyl-terminated dimethyl siloxane
  • the organosilicon hydride is a hydrogen-terminated dimethyl siloxane
  • the non-reactive organopolysiloxane is a polydimethylsiloxane (PDMS).
  • the first polymeric composition includes, consists essentially of, or consists of: two different dimethylvinyl-terminated polydimethylsiloxanes; a dimethylhydrogen-terminated polydimethylsiloxane; and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule.
  • the polymeric strips 44 can be the reaction product of these components. The reaction can be catalyzed by a hydrosilylation catalyst, e.g. a platinum-ligand complex, which can be included in, or added to, the first polymeric composition.
  • the reaction typically occurs in the presence of a PDMS, which can also be included in, or added to, the first polymeric composition.
  • a PDMS is non-reactive, e.g. non- reactive toward the aforementioned reactants of the first polymeric composition.
  • inclusion of components, such as PDMS, is useful for adjusting physical properties of the reaction product.
  • the components of the first polymeric composition may be included in various amounts.
  • the first polymeric composition includes greater than about 45, greater than about 50, greater than about 55, greater than about 60, or greater than about 65, parts by weight of the diorganopolysiloxane, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.
  • the first polymeric composition includes from about 2.5 to about 7.5, about 3 to about 7, or about 3.5 to about 6.5, parts by weight of the organosilicon hydride, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.
  • the first polymeric composition has from about 25 to about 65, or about 30 to about 60, parts by weight of the non-reactive organopolysiloxane, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.
  • the first polymeric composition may also be referred to in the art as an encapsulant composition.
  • suitable encapsulant compositions suitable for use as the first polymeric composition are commercially available from Dow Corning Corporation of Midland, Ml, such as Dow Corning® PV-6100 Cell Encapsulant. Further examples of suitable encapsulant compositions include those described in the incorporated references, such as those described as the "silicone encapsulant" in the '277 application.
  • the polymeric strips 44 are disposed on the rear face 40 of the PV cell 36.
  • the polymeric strips 44 encapsulate at least a portion of the tabbing ribbons 42 that are on the rear face 40.
  • the polymeric strips 44 are in direct, e.g. physical, contact with the rear face 40 of the PV cell 36.
  • the polymeric strips 44 typically have a substantially parabolic-shaped cross-section.
  • the polymeric strips 44 may also have different shapes, i.e., they need not be perfectly shaped parabolas as depicted.
  • the polymeric strips 44 are disposed in line with the tabbing ribbons 42. Specifically, the first polymeric strip 44a is aligned with the first tabbing ribbon 42a and the second polymeric strip 44b is aligned with the second tabbing ribbon 42b.
  • the polymeric strips 44 extend laterally across the module 20 to a periphery of the module 20 on ends of the module 20.
  • the polymeric strips 44 may be continuous or there may be gaps therebetween, such as between adjacent PV cells 36 where the tabbing ribbon 42 transitions from the rear face 40 to the front face 38 of the PV cells 36.
  • the polymeric strips 44 are further disposed on the front face 26 of the substrate 24 opposite the tabbing ribbon 42. Said another way, the polymeric strips 44 are disposed between the front face 26 of the substrate 24 and the rear face 40 of the PV cell 36. In certain embodiments, the polymeric strips 44 are in direct contact with the rear face 40 of the PV cell 36 and/or are in direct contact with the front face 26 of the substrate 24. In these embodiments, the polymeric strips 44 typically have a substantially rectangular-shaped cross-section. The polymeric strips 44 may also have different shapes, i.e., they need not be perfectly shaped rectangles as depicted.
  • the edges of the polymeric strips 44 are illustrated as being concave, the edges may be straight, convex, slanted, or a combination of shapes.
  • the polymeric strips 44 are disposed on the front face 26 of the substrate 24 opposite the tabbing ribbon 42.
  • the polymeric strips 44 are in contact with and/or encapsulate at least a portion of the tabbing ribbon 42.
  • the polymeric strips 44 are in direct contact with the front face 26 of the substrate 24.
  • the polymeric strips 44 typically have a substantially parabolic-shaped cross-section.
  • the polymeric strips 44 may also have different shapes, i.e., they need not be perfectly shaped parabolas as depicted.
  • the polymeric strips 44 can be of various thicknesses, such as from about 0.05 to about 0.75, about 0.125 to about 0.4, or about 0.125 to about 0.25, mm on average, or any range between the lowest and highest of these values. Typically, the thickness of the polymeric strips 44 is varied to minimize the amount of the first polymeric composition that is used, thereby reducing production costs of the module 20, and also to simultaneously minimize or prevent bottoming out of the PV cells 36 and/or the tabbing ribbon 42.
  • bottoming out refers to a situation where the PV cells 36 and/or the tabbing ribbon 42 would contact the substrate 24, which could cause damage. Such a situation can arise during manufacture and/or use of the module 20. This situation is undesirable. As such, the polymeric strips 44 are useful for cushioning and protecting the PV cells 36 and the tabbing ribbon 42 from the substrate 24 in situations where they could potential come into contact with one another.
  • Each of the polymeric strips 44 can be of various widths, such as from about 2 to about 25, about 3 to about 20, or about 6 to about 13, mm on average, or any range between the lowest and highest of these values. Width of the polymeric strips 44 may be uniform or may vary. Typically, as best shown in FIGs. 2-5, each of the polymeric strips 44 has a width less than the width of the one of the PV cells 36, but greater than a width of one of the tabbing ribbons 42.
  • a tie-layer 46 is disposed between the substrate 24 and the cover sheet 30.
  • the tie-layer 46 is also disposed around the PV cells 36.
  • the tie-layer 46 is useful for coupling the rear face 34 of the cover sheet 30 to the front face 26 of the substrate 24.
  • the tie-layer 46 is also useful for coupling the front face 38 of the PV cell 36 to the rear face 34 of the cover sheet 30.
  • “coupling” generally means physically connecting, unless indicated otherwise.
  • the tie-layer 46 may also be referred to in the art as a polymeric tie-layer 46.
  • the tie-layer 46 is formed from a second polymeric composition.
  • the second polymeric composition of the tie-layer 46 is different from the first polymeric composition of the polymeric strips 44.
  • the first and second polymeric compositions can be different in various ways, such as being chemically and/or physically different. Typically, the first and second polymeric compositions are different in such a way to provide different moduli of elasticity. Examples of differences are described below.
  • the second polymeric composition may be formed from various polymer compositions.
  • the second polymeric composition is a silicone, more typically a silicone elastomer.
  • suitable polymeric compositions include hydrosilylation- reaction, condensation-reaction, and hydrosilylation/condensation-reaction, curable silicone compositions.
  • the tie-layer 46 is formed from a hydrosilylation-reaction curable silicone composition.
  • the second polymeric composition comprises a diorganopolysiloxane having alkenyl groups (e.g. vinyl groups), and an organosilicon hydride having silicon-bonded hydrogen atoms reactive with the alkenyl groups of the diorganopolysiloxane.
  • suitable diorganopolysiloxanes, organosilicon hydrides, and non-reactive organopolysiloxanes include those described in the incorporated references.
  • the diorganopolysiloxane and the organosilicon hydride will generally react, optionally, in the presence of additional components, to form a silicone polymer.
  • suitable additive components such as catalysts, include those described in the incorporated references.
  • the diorganopolysiloxane is a dimethylvinyl-terminated dimethyl siloxane
  • the organosilicon hydride is a hydrogen -terminated dimethyl siloxane
  • the second polymeric composition is different than the first polymeric composition.
  • An example of a difference between the first and second polymer compositions is the inclusion of the non-reactive organopolysiloxane in the first polymeric composition while the second polymeric composition excludes the non-reactive organopolysiloxane.
  • the second polymeric composition includes, consists essentially of, or consists of: a dimethylvinyl-terminated polydimethylsiloxane; a dimethylhydrogen-terminated polydimethylsiloxane; and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule.
  • the tie-layer 46 can be the reaction product of these components. The reaction can be catalyzed by a hydrosilylation catalyst, e.g. a platinum-ligand complex, which can be included in, or added to, the second polymeric composition.
  • the components of the second polymeric composition may be included in various amounts.
  • the second polymeric composition includes greater than about 55, greater than about 60, or greater than about 65, parts by weight of the diorganopolysiloxane, each based on 100 parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
  • the second polymeric composition includes from about 5 to about 25, about 5 to about 20, or about 8 to about 22.5, parts by weight of the organosilicon hydride, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.
  • the second polymeric composition may also include additional components, such as silanes or siloxanes. Such components can be included in various amounts.
  • the second polymeric composition further comprises an organosilane and/or a dimethyl methylhydrogen siloxane. Such components can be included in various amounts, such as less than about 5 parts by weight, or from about 0.1 to about 2.5 parts by weight, each based on 100 parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
  • the second polymeric composition includes, consists essentially of, or consists of: a dimethylvinyl-terminated polydimethylsiloxane; and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule.
  • the tie-layer 46 can be the reaction product of these components.
  • the reaction can be catalyzed by a hydrosilylation catalyst, e.g. a platinum- ligand complex, which can be included in, or added to, the second polymeric composition.
  • the components of the second polymeric composition may be included in various amounts.
  • the second polymeric composition includes from about 80 to about 99.9, about 90 to about 99.9, or about 95 to about 99.9, parts by weight of a dimethylvinyl-terminated polydimethylsiloxane (e.g. a dimethyl siloxane, dimethylvinylsiloxy-terminated polymer), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
  • the second polymeric composition includes from about 0.01 to about 2, about 0.05 to about 1 , or about 0.05 to about 0.5, parts by weight of a platinum-ligand complex (e.g.
  • the second polymeric composition includes from about 0.01 to about 7.5, about 0.1 to about 5, or about 0.2 to about 2.5, parts by weight of an alkoxysilane (e.g. methacryloxypropyltrimethoxysilane), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
  • an alkoxysilane e.g. methacryloxypropyltrimethoxysilane
  • the second polymeric composition includes from about 0.05 to about 7.5, about 0.1 to about 5, or about 0.5 to about 2.5, parts by weight of a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule (e.g. dimethyl, methylhydrogen siloxane, trimethylsiloxy-terminated), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
  • the second polymeric composition includes from about 0.001 to about 2.5, about 0.005 to about 1 , or about 0.005 to about 0.5, parts by weight of a siloxane (e.g. tetramethyltetravinylcyclotetrasiloxane), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
  • the second polymeric composition may also be referred to in the art as an encapsulant composition.
  • suitable encapsulant compositions suitable for use as the second polymeric composition are commercially available from Dow Corning Corporation, such as Dow Corning® PV-6150 Cell Encapsulant. Further examples of suitable encapsulant compositions include those described in the incorporated references, such as those described as the "silicone tie layer" in the '277 application.
  • the tie-layer 46 can be of various thicknesses, such as from about 0.125 to about 1 .25, about 0.25 to about 0.5, or about 0.3 to about 0.4, mm on average, or any range between the lowest and highest of these values. Thickness of the tie-layer 46 is generally defined between the cover sheet 30 and the substrate 24. Thickness can also be defined by one or more intermediate layers, if present. The intermediate layers are described below. Typically, the thickness of the tie-layer 46 is varied to minimize the amount of the second polymeric composition that is used, thereby reducing production costs of the module 20, and also to simultaneously minimize or prevent bottoming out of the PV cells 36 and/or the tabbing ribbon 42. Width of the tie-layer 46 is equal to or approaching the width of the module 20. As illustrated in the figures, the width of each of the polymeric strips 44 is less than the width of the tie-layer 46.
  • bottoming out refers to a situation where the PV cells 36 and/or the tabbing ribbon 42 would contact the cover sheet 30 and/or the substrate 24 which could cause damage. Such a situation can arise during manufacture and/or use of the module 20. This situation is undesirable. As such, the tie-layer 46 is useful for cushioning and protecting the PV cells 36 and the tabbing ribbon 42.
  • the tie-layer 46 is sandwiched between the cover sheet 30 and the substrate 24 as best illustrated in FIGs. 2, 4, and 5; however, there may be at least one intervening layer (not shown) between the tie-layer 46 and the cover sheet 30 and/or between the tie-layer 46 and the substrate 24.
  • an intervening layer disposed between the tie-layer 46 and the substrate 24.
  • Such an intervening layer is useful for thickness control and module 20 strength.
  • An example of suitable intervening layer is a nonwoven fiberglass (FG) layer. If included, the intervening layer may also be formed from other materials, such as PET, nylon, or silicone.
  • the module 20 includes a nonwoven FG layer disposed between the substrate 24 and the tie-layer 46. In other embodiments, the module 20 is free of the intervening layer(s).
  • the modulus of elasticity of the tie-layer 46 is greater than the modulus of elasticity of the polymeric strips 44.
  • the polymeric strips 44 are generally softer than the tie-layer 46.
  • having different moduli is useful for protecting the PV cells 36 and the tabbing ribbon 42 as described above.
  • the moduli can vary depending on the type of first and second polymeric compositions utilized.
  • the shear modulus of elasticity of the tie- layer 46 is from about 15 to about 50, about 17.5 to about 40, or about 20 to about 30, kilopascals (kPa), and the shear modulus of elasticity of the polymeric strips 44 is from about 0.5 to about 12.5, about 1 to about 10, about 1 to about 7.5, about 1 to about 5, or about 1 to about 3, kPa, or any range between the lowest and highest of these values.
  • the shear modulus of elasticity of the tie-layer 46 is from about 50 to about 2000, about 50 to about 1750, about 50 to about 1500, about 50 to about 1250, about 50 to about 1000, about 50 to about 750, about 75 to about 600, about 100 to about 500, about 150 to about 450, about 200 to about 400, or about 200 to about 300, kPa, and the shear modulus of elasticity of the polymeric strips 44 is as just described, or any range between the lowest and highest of these values. As described above, it is believed that the modulus of elasticity of the tie-layer 46 helps to maintain orientation of the PV cells 36 when the module 20 is exposed to changes in temperature (e.g. during thermo-cycling, expansion/contraction, etc.).
  • the module 20 can be of various shapes, sizes, and configurations. In certain embodiments, the module 20 has a length of from about 1 .6 to about 2.0 and a width of from about 0.7 to about 1 .1 , meters (m) or any range between the lowest and highest of these values. The module 20 is not limited to any particular shape, length or width.
  • the module 20 can further include "polymeric strips" as described in U.S. Pat. App. Ser. No. 61 /590996 (Attorney Docket No. DC1 1204 PSP1 ; 071038.00786), and/or a "peripheral tie-layer" as described in U.S. Pat. App. Ser. No. 61 /591005 (Attorney Docket No. DC1 1205 PSP1 ; 071038.00787), the disclosures of which are incorporated by reference in their entirety to the extent they do not conflict with the general scope of the present invention.
  • the module 20 can include additional components, e.g. at least one spacer disposed along the perimeter. Such components are described in the incorporated references.
  • the invention method of forming the invention module 20 comprises the step of applying the first polymeric composition on the front face 26 of the substrate 24 and/or the rear face 40 of the PV cell 36 to form the polymeric strip 44 on the face(s) 26, 40.
  • the first polymeric composition is applied on the front face 26 of the substrate 24 to form the polymeric strip 44.
  • the first polymeric composition is applied on the rear face 40 of the PV cell 36 to form the polymeric strip 44, or a portion thereof as described immediately hereafter.
  • the first polymeric composition is also applied on the front face 26 of the substrate 24 to form the polymeric strip 44, in addition to the rear face 40 of the PV cell 36, to further form a remaining portion of the polymeric strip 44.
  • the polymeric strip 44 is generally in an uncured state, e.g. liquid form, to promote ease of application.
  • the first polymeric composition generally has enough body to prevent flow off of the face(s) 26, 40 and/or to generally maintain shape of the polymeric strip 44.
  • the first polymeric composition can be applied to the face(s) 26, 40 by various means, such as by spraying, dispensing, flow coating, injecting, etc.
  • the polymeric strips 44 are pre-formed and disposed on the face(s) 26, 40 of the PV cell 36.
  • a polymeric sheet can be made from the first polymeric composition and cut into the polymeric strips 44, or the polymeric strips can be pre-made from the first polymeric composition and disposed on the face(s) 26, 40 of the PV cell 36.
  • the first polymeric composition is dispensed (or disposed) on the face(s) 26, 40 robotically.
  • a robotic dispenser 48a is shown applying the first polymeric composition to the substrate 24 and to the PV cell 36.
  • the robotic dispenser 48a is shown applying the first polymeric composition just to the substrate 24.
  • the robotic dispenser 48a is shown applying the first polymeric composition just to the PV cell 36.
  • the robotic dispenser 48a typically has one or more nozzles 50, from which the first polymeric composition dispenses.
  • the nozzles 50 can be selectively turned on or off to provide polymeric strips 44 of various widths. As such, one or more nozzles 50 may be used to form each of the polymeric strips 44.
  • the polymeric strips 44 may be formed separately or simultaneously, i.e., at the same or at different times.
  • the robotic dispenser 48a can be on a track and/or arm (not shown) and programmed to move along the length and/or width of the substrate 24 and/or PV cell 36 to form the polymeric strips 44.
  • the substrate 24 and/or PV cell 36 can also be moved relative to the robotic dispenser 48a, or both can move relative to each other.
  • the first polymeric composition can be applied to the face(s) 26, 40 in various amounts.
  • the first polymeric composition can be applied such that the polymeric strips 44 each have a width of from about 5 to about 13 mm on average and a thickness of from about 0.125 to about 0.75 mm on average, or any range between the lowest and highest of these values.
  • each of the portions may be of the same or different thickness.
  • the thicknesses of each of the portions collectively define the thickness of the polymeric strips 44 as described above.
  • the polymeric strips 44 are formed from two portions.
  • the method further comprises the step of applying the second polymeric composition to the rear face 34 of the cover sheet 30 to form the tie-layer 46, or a portion thereof as described below.
  • the tie-layer 46 is generally in an uncured state, e.g. liquid form, to promote ease of application.
  • the second polymeric composition generally has enough body to prevent flowing off of the rear face 34 and/or to generally maintain the shape of the tie-layer 46.
  • the second polymeric composition can be applied to the rear face 34 by various means, such as by spraying, dispensing, flow coating, injecting, etc. In certain embodiments, the second polymeric composition is dispensed on the rear face 34 robotically.
  • a robotic dispenser 48b is shown applying the second polymeric composition to the cover sheet 30 and to the PV cell 36 and polymeric strips 44.
  • the robotic dispenser 48b is shown applying the second polymeric composition to just the cover sheet 30 and PV cell 36.
  • the robotic dispenser 48b can be the same as or different than the robotic dispenser 48a that applies the first polymeric composition.
  • the robotic dispenser 48b can be on a track and/or arm (not shown) and programmed to move along the length and/or width of the cover sheet 30 and/or PV cell 36 to form the tie-layer 46.
  • the cover sheet 30 and/or PV cell 36 can also be moved relative to the robotic dispenser 48b, or both can move relative to each other.
  • the nozzles 50 can be selectively turned on or off to control application amount and location of the second polymeric composition.
  • the second polymeric composition can be applied in various amounts to form the tie-layer 46.
  • the second polymeric composition is applied such that the tie-layer 46 has a thickness of from about 0.125 to about 1 .25 mm on average, or any range between these values.
  • the PV cells 36 are disposed on the tie-layer 46.
  • the PV cells 36 are disposed on the tie-layer 46 such that the rear faces 40 of the PV cells 36 are disposed opposite the cover sheet 30.
  • the tie-layer 46 can be allowed to level prior to disposing the PV cells 36 to prevent gaps, voids, or other issues.
  • the PV cells 36 may be disposed separately or simultaneously.
  • the PV cells 36 may be disposed by various means, such as by hand or by robotic grip 52a.
  • the robotic grip 52a can use vacuum or other means to hold the PV cells 36.
  • the robotic grip 52a can be operatively connected to a track and/or arm (not shown) for movement.
  • the PV cells 36 can simply be placed on top of the tie-layer 46 or slightly pressed into the tie-layer 46. Pressing generally ensures that no gaps or voids are present between the tie-layer 46 and the PV cells 36.
  • the tie-layer 46 may be cured (to a final cure state or partially thereto) prior to or after the PV cells 36 are disposed.
  • the tie-layer 46 can be cured via oven prior to disposing the PV cells 36. Applying heat to the tie-layer 46 generally facilitates cure of the tie-layer 46 from an uncured state to a final cured state.
  • the polymeric strips 44 can also be cured prior to the PV cells 36 being disposed, in addition or alternate to, the tie-layer 46 being cured.
  • the tie-layer 46 can be cured prior to, after, or at the same time as the polymeric strips 44.
  • a third polymeric composition is applied over the PV cells 32 to fully encapsulate the PV cells 32 and to further form the tie-layer 46.
  • the third polymeric composition is the same as the second polymeric composition, such as shown in FIGs. 6-8.
  • the third polymeric composition can be the same as the first polymeric composition, or can be different from both the first and second polymeric compositions.
  • the third polymeric composition can be different in various ways, such as providing a modulus that falls between those provided by the first and second polymeric compositions, or a modulus that is less than or greater than those provided by the first and second polymeric compositions.
  • the third polymeric composition can be applied as like described above with description of the first and second polymeric compositions, such as by the robotic dispenser 48.
  • the third polymeric composition can be cured at various times.
  • the third polymeric composition can be a silicone.
  • the tie-layer 46 can be cured before or after application of the third polymeric composition, if employed.
  • the substrate 24 and the cover sheet 30 are combined to form the module 20.
  • the substrate 24 and cover sheet 30 can be combined in various ways.
  • the substrate 24 can be laid over the tie-layer 46 to form the module 20.
  • the substrate 24 and cover sheet 30 can be pressed together to form the module 20.
  • a robotic grip 52b can be used for moving the substrate 24 and/or the cover sheet 30 into place; however, other means can also be used.
  • the tie-layer 46 may also have portions formed from the third polymeric composition as described above (where the third is different than the first and second).
  • the tie-layer 46 is generally at a viscosity, at the time of combining the substrate 24 and the cover sheet 30, which allows for any air that may be trapped within/by the tie-layer 46 to migrate outwardly therefrom. In this way, bubbles are not formed and/or trapped, as bubbles could create issues for the module 20.
  • the viscosity can be an initial viscosity of the second polymeric composition (i.e., pre-cure), or a higher viscosity that arises after at least partial cure of the tie-layer 46. While not required, these embodiments may be useful in instances where the module 20 is cured via a vacuum- press process.
  • the silicone composition used to form the tie-layer 46 typically has a complex (dynamic) viscosity of from 10,000 to 5,000,000 cPs at 25°C measured at 1 radian per second at 1 to 5% strain. More specifically, a Frequency Sweep is generated on a TA Instruments, HR-2 parallel plate Rheometer. A sample is loaded between two 25 mm parallel plates to a 2 mm thickness. The frequency sweep is run from 0.1 rad/sec to 100 rad/sec at a 5% strain, the dynamic (complex) viscosity is reported at 1 rad/sec in cP.
  • the complex viscosity is from 15,000 to 100,000, from 20,000 to 95,000, from 25,000 to 90,000, from 30,000 to 85,000, from 35,000 to 75,000, from 40,000 to 70,000, from 45,000 to 65,000, from 50,000 to 60,000, or from 55,000 to 60,000, cPs at 25°C measured as described above. In other embodiments, the complex viscosity is from 50,000 to 100,000, from 55,000 to 95,000, from 60,000 to 90,000, from 65,000 to 85,000, from 70,000 to 80,000, or from 75,000 to 80,000, cPs at 25°C measured as described above.
  • the complex viscosity is from 35,000 to 300,000, from 40,000 to 295,000, from 45,000 to 290,000, from 50,000 to 285,000, from 55,000 to 280,000, from 60,000 to 275,000, from 65,000 to 275,000, from 70,000 to 270,000, from 75,000 to 265,000, from 80,000 to 260,000, from 85,000 to 255,000, from 90,000 to 250,000, from 95,000 to 245,000, from 100,000 to 240,000, from 105,000 to 235,000, from 1 10,000 to 230,000, from 1 15,000 to 225,000, from 120,000 to 220,000, from 125,000 to 215,000, from 130,000 to 210,000, from 135,000 to 205,000, from 140,000 to 200,000, from 145,000 to 195,000, from 150,000 to 190,000, from 155,000 to 185,000, from 160,000 to 180,000, from 165,000 to 175,000, or from 165,000 to 170,000, from 80,000 to 200,000, from 40,000 to 200,000, or from 40,000 to 300,000, cPs at 25°C measured as described above
  • the complex viscosity is from 100,000 to 1 ,000,000, from 125,000 to 975,000, from 150,000 to 950,000, from 175,000 to 925,000, from 200,000 to 900,000, from 225,000 to 875,000, from 250,000 to 850,000, from 275,000 to 825,000, from 300,000 to 800,000, from 325,000 to 775,000, from 350,000 to 750,000, from 375,000 to 725,000, from 400,000 to 700,000, from 425,000 to 675,000, from 450,000 to 650,000, from 475,000 to 625,000, from 500,000 to 600,000, from 525,000 to 575,000, or from 550,000 to 575,000, cPs at 25°C measured as described above.
  • the complex viscosity is from 1 ,125,000 to 1 ,975,000, from 1 ,150,000 to 1 ,950,000, f rom 1 ,175,000 to 1 ,925,000, f rom 1 ,200,000 to 1 ,900,000, from 1 ,225,000 to 1 ,875,000, f rom 1 ,250,000 to 1 ,850,000, f rom 1 ,275,000 to 1 ,825,000, from 1 ,300,000 to 1 ,800,000, f rom 1 ,325,000 to 1 ,775,000, f rom 1 ,350,000 to 1 ,750,000, from 1 ,375,000 to 1 ,725,000, f rom 1 ,400,000 to 1 ,700,000, f rom 1 ,425,000 to 1 ,675,000, from 1 ,450,000 to 1 ,650,000, f rom 1 ,475,000 to 1 ,625,000, f rom 1 ,500,000 to 1 ,600,
  • the silicone composition may have a complex viscosity of from 10,000 to 50,000,000 cPs at 25°C measured as described above. Any of the aforementioned values may, for example, vary by 1 , 2, 3, 4, 5, 10, 15, 20, or 25+ % in varying non-limiting embodiments. All values, and ranges of values, between and including the aforementioned values are also hereby expressly contemplated in various non-limiting embodiments.
  • the aforementioned viscosity is the complex viscosity of the silicone composition before curing. After curing, the cured reaction product is typically a solid but may also be a gel.
  • the second polymeric composition is applied in a pattern defining at least one passage (not shown) extending from an interior of module 20 to a perimeter of the module 20 to form the tie-layer 46.
  • the pattern is not particularly limited and may be further described as a geometric, non-geometric, uniform or non-uniform pattern.
  • the silicone composition is deposited in one, two, or a plurality of rows. One or more of the rows may be disposed substantially parallel or traverse (i.e., at an angle) with one or more other rows.
  • the passages formed from the silicone composition may extend to opposing or different locations on the perimeter of the module 20. This may be achieved based on the disposition of the one or more rows of the silicone composition.
  • patterning can be used for the first polymeric composition, in addition or alternate to the second polymeric composition.
  • patterning is useful for the more viscous/heavier of the two polymeric compositions.
  • suitable patterns/patterning methodology, as well as the benefits thereof, include those described in the incorporated '277 application.
  • the passage is also not particularly limited. Typically, the passage is defined on two or more sides by the deposition of the silicone composition.
  • the passage may alternatively be described as a conduit, duct, fluting, furrow, gouge, groove, gutter, pass, passage, trough, channel, lane, opening, or pathway.
  • the passage extends from an interior of the module 20 to the perimeter (e.g. an exterior) of the module 20 and may originate at any point on the interior of the module 20.
  • the passage may extend across an entirety of the interior or across a portion of the interior.
  • the passage may extend to two or more points on the perimeter of the module 20 or a single point.
  • the passage may be further defined as one, two, or a plurality of individual passages that may be connected or not connected to each other in whole or in one or more parts. Air, e.g. from bubbles, may pass through the passage to the perimeter of the module 20 before the deposited silicone composition defining the passage merges together to fill in and thereby eliminate the passage.
  • the passage is defined such that air can pass through the passage and exit the module 20 to reduce or eliminate the presence of any air bubbles in one or more layers, e.g. the tie-layer 46.
  • the passage typically allows air to flow from an interior of the module 20 (e.g. from a center), out towards a perimeter of the module 20 (e.g. to the edges), thereby minimizing the amount of air trapped in the module 20 in any one or more layers or components.
  • the polymeric strips 44 when the polymeric strips 44 are aligned with the tabbing ribbon 42, the polymeric strips 44 provide a soft surface for the tabbing ribbon 42 to be pressed against when pressure is applied to the module 20. Providing such a soft surface or cushion, prevents the PV cells 36 from cracking. This is especially true when the substrate 24 and/or cover sheet 30 are both formed from glass, where the glass could potentially come into contact with the PV cells 36 but for the presence of the polymeric strips 44. As such, the polymeric strips 44 can also provide for a thinner tie-layer 46 relative to conventional tie-layers, especially between the substrate 24 and the PV cells 32.

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  • Photovoltaic Devices (AREA)

Description

A PHOTOVOLTAIC CELL MODULE AND METHOD OF FORMING THE SAME
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 61/591 ,000, filed on January 26th, 2012, which is incorporated herewith by reference in its entirety.
BACKGROUND
[0002] The present invention generally relates to a photovoltaic (PV) cell module and to a method of forming the PV cell module.
[0003] Solar or PV cells are semiconductor devices used to convert light into electricity. In many applications, the PV cells are encapsulated by an encapsulant to form PV cell modules. The modules typically include a cover sheet (or "superstrate") and a back sheet (or "substrate"), such that the PV cells and encapsulant are sandwiched between the cover sheet and substrate. The PV cells are operatively connected to one another with tabbing ribbon. The encapsulant and cover sheet protect the PV cells from environmental factors, such as wind, dirt, and rain. A common encapsulant is ethyl vinyl acetate (EVA) and another is silicone. EVA has one or more drawbacks, such as low UV resistance, degradation over time, discoloration over time, etc. As such, silicone has been used in certain applications to replace EVA in modules. A single type of encapsulant can be used to completely encapsulate the PV cells within the module. Alternatively, a layer of a first encapsulant is used between the PV cells and the cover sheet and a layer of a second encapsulant, different from the first, is used between the PV cells and the substrate. Typically, the module is formed by pressing. As such, the encapsulant needs to be of sufficient thickness to prevent the one of both of the sheets from coming into contact with the PV cells during pressing, otherwise, the sheet(s) could contact the PV cells, thus cracking them.
[0004] Unfortunately, having thick layers of encapsulant within the module increases the weight and cost of manufacture. Increasing thickness of the encapsulant also reduces the efficiency of the module. Conversely, thinning out the encapsulant too much will cause damage to the PV cells during manufacture, e.g. pressing, of the module. This is especially true with the encapsulant between the back sheet and PV cells. Accordingly, there remains an opportunity to provide improved modules having reduced weight and manufacturing cost, as well as having excellent durability, such as improved resistance to cell cracking during manufacture. There also remains an opportunity to provide improved methods of forming modules that can provide excellent production efficiency, cost savings, and repeatability. SUMMARY OF THE INVENTION
[0005] The present invention provides a photovoltaic (PV) cell module. The invention module comprises a substrate having a front face and a rear face spaced from the front face of the substrate. The module also comprises a cover sheet having a front face and a rear face spaced from the front face of the cover sheet. At least one PV cell is disposed between the substrate and the cover sheet. The PV cell has a front face and a rear face spaced from the front face of the PV cell. At least one tabbing ribbon is disposed on the rear face of the PV cell. At least one polymeric strip is disposed between the substrate and the PV cell adjacent the tabbing ribbon for protecting the tabbing ribbon from the front face of the substrate. The polymeric strip is formed from a first polymeric composition. A tie- layer is disposed between the substrate and the cover sheet and around the PV cell for coupling the rear face of the cover sheet to the front face of the substrate and for coupling the front face of the PV cell to the rear face of the cover sheet. The tie-layer is formed from a second polymeric composition different than the first polymeric composition of the polymeric strip.
[0006] The present invention also provides a method of forming the invention module. The invention method comprises the step of applying the first polymeric composition on i) the front face of the substrate and/or ii) the rear face of the PV cell to form the polymeric strip on the front face of the substrate and/or the rear face of the PV cell in an uncured state. The method further comprises the step of applying the second polymeric composition on the ii) rear face of the cover sheet to form the tie-layer in an uncured state. The method further comprises the step of disposing the PV cell on the tie-layer such that the rear face of the PV cell is disposed opposite the cover sheet. The method further comprises the step of combining the substrate and the cover sheet to form the module such that the tie-layer is sandwiched between the cover sheet and the substrate and the polymeric strip is disposed adjacent the tabbing ribbon for protecting the tabbing ribbon from the front face of the substrate. The module may be used for various applications, such as for converting light of many different wavelengths into electricity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention may be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
[0008] FIG. 1 is perspective view of a pair of photovoltaic (PV) arrays each including an embodiment of PV cell modules; [0009] FIG. 2 is a broken cross-sectional side-view of an embodiment of the PV cell module including a cover sheet, a substrate, a PV cell, tabbing ribbon, a tie-layer, and polymeric strips;
[0010] FIG. 3 is a partial top down view of the PV cell module of FIG. 2 taken along line 3- 3;
[0011] FIG. 4 is a broken cross-sectional side-view of another embodiment of the PV cell module;
[0012] FIG. 5 is a broken cross-sectional side-view of another embodiment of the PV cell module;
[0013] FIG. 6 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of a method suitable to form the PV cell module of FIG. 4;
[0014] FIG. 7 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of a method suitable to form the PV cell module of FIG. 5; and
[0015] FIG. 8 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of a method suitable to form the PV cell module of FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring to the Figures (FIGs.), wherein like numerals indicate like parts throughout the several views, a photovoltaic (PV) cell module formed in accordance with the invention method is shown generally at 20. The PV cell module 20 is hereinafter referred to as the module 20. The components of the invention module 20 are not necessarily drawn to scale in the figures, such that they may be larger or smaller than that which is depicted.
[0017] Referring to FIG. 1 , a plurality of modules 20 is connected to form a pair of arrays 22. The arrays 22 may be planar or non-planar. While shown in this configuration/arrangement, the module 20 may be used alone or in a group of two or more (e.g., as shown in FIG. 1 ), and may be used for various applications, such as for structures, buildings, vehicles, devices, etc. The present invention is not limited to any particular configuration or use of the modules 20 or arrays 22. The modules 20 can be used to convert light energy into electrical energy.
[0018] Referring to FIG. 2, the module 20 comprises a substrate 24. The substrate 24 has a front face 26 and a rear face 28 spaced from the front face 26. The substrate 24 may be substantially planar or non-planar. The substrate 24 may also be referred to in the art as a backsheet 24. The substrate 24 is useful for providing support, protection, and/or an interface for the module 20. [0019] The substrate 24 can be formed from various materials. Examples of suitable materials include glass, polymeric materials, composite materials, etc. For example, the substrate 24 can be formed from glass, polyethylene terephthalate (PET), thermoplastic elastomer (TPE), polyvinyl fluoride (PVF), silicone, etc. The substrate 24 may be formed from a combination of different materials, e.g. a polymeric material and a fibrous material. The substrate 24 may have portions formed from one material, e.g. glass, and other portions formed from another material, e.g. a polymeric material.
[0020] The substrate 24 can be of various thicknesses, such as from about 0.05 to about 5.0, about 0.1 to about 4, or about 0.125 to about 3.2, millimeters (mm) on average, or any range between the lowest and highest of these values. Thickness of the substrate 24 may be uniform or may vary.
[0021] Further examples of suitable substrates 24 include those described in U.S. App. Pub. Nos. 2008/0276983, 201 1/0005066, and 201 1/0061724, and in WO Pub. Nos. 2010/051355 and 2010/141697. Yet further examples of suitable substrates 24 include those described as "backsheets" in U.S. Pat. App. Ser. No. 61 /725277 ("the '277 application"; Attorney Docket No. DC1 1521 PSP1 ; 071038.01095). The aforementioned disclosures are hereinafter referred to as the "incorporated references", which are incorporated herein by reference in their entirety to the extent they do not conflict with the general scope of the present invention. If any conflict exists between the instant disclosure and any of the incorporated reference(s), only the portion(s) of any of the incorporated reference(s) that are in conflict with the instant disclosure, rather than an entirety of any of the incorporated reference(s), are expunged from incorporation herein from the incorporated reference(s).
[0022] The module 20 further comprises a cover sheet 30. The cover sheet 30 has a front face 32 and a rear face 34 spaced from the front face 32. The cover sheet 30 may be substantially planar or non-planar. The cover sheet 30 is useful for protecting the module 20 from environmental conditions such as rain, snow, dirt, heat, etc. Typically, the cover sheet 30 is transparent to UV and/or visible light for gathering light energy. Said another way, the cover sheet 30 is typically optically transparent. The cover sheet 30 is generally the sun side or front side of the module 20.
[0023] The cover sheet 30 can be formed from various materials. Examples of suitable materials include those described above with the substrate 24. Further examples of suitable cover sheets 30 include those described in the incorporated references. In certain embodiments, the cover sheet 30 is formed from glass. Various types of glass can be utilized such as silica glass, polymeric glass, etc. The cover sheet 30 may be formed from a combination of different materials. The cover sheet 30 may have portions formed from one material, e.g. glass, and other portions formed from another material, e.g. a polymeric material. The cover sheet 30 may be the same as or different from the substrate 24. For example, both the cover sheet 30 and the substrate 24 may be formed from glass with equal or differing thicknesses. In certain embodiments, both the cover sheet 30 and the substrate 24 are formed from glass.
[0024] The cover sheet 30 can be of various thicknesses, such as from about 0.5 to about 10, about 1 to about 7.5, about 2.5 to about 5, or about 3, mm on average, or any range between the lowest and highest of these values. In certain embodiments, the substrate 24 is of a similar or the same thickness as the cover sheet 30, e.g. when both are formed from glass. Thickness of the cover sheet 30 may be uniform or may vary. Further examples of suitable cover sheets 30 include those described in the incorporated references, such as those described as the "superstrates" in the '277 application.
[0025] The module 20 further comprises at least one PV cell 36, alternatively, a plurality of PV cells 36. The PV cells 36 are disposed between the substrate 24 and the cover sheet 30. The PV cell 36 has a front face 38 and a rear face 40 spaced from the front face 38. The PV cells 36 are typically substantially coplanar with one another. The PV cells 36 can be arranged in various patterns, such as a series of PV cells 36 in a grid-like pattern. The present invention is not limited to any particular pattern. The PV cells 36 may be offset from one another, such as in non-planar module 20 configurations.
[0026] The PV cells 36 may be of various dimensions, be of various types, and be formed from various materials. Examples of suitable PV cells 36 include those described in the incorporated references. The PV cells 36 may be the same as or different from each other. The PV cells 36 can be of various thicknesses, such as from about 50 to about 250, about 100 to about 225, about 175 to about 225, or about 180, μηι on average, or any range between the lowest and highest of these values. The PV cells 36 can also be of various widths and lengths as understood in the art. In certain embodiments, the PV cells 36 may be referred to in the art as crystalline silicon PV cells 36. Further examples of suitable PV cells 36 include those described in the incorporated references, such as those described in the '277 application.
[0027] Tabbing ribbon 42 is disposed between the PV cells 36. The tabbing ribbon 42 is useful for establishing a circuit in the module 20. As best shown in FIGs. 2-5, the tabbing ribbon 42 typically extends over the faces 38, 40 of the PV cells 36. A series of two or more connected PV cells 36 may be referred to in the art as a string of cells. Typically, there is a first tabbing ribbon 42a and a second tabbing ribbon 42b spaced from the first tabbing ribbon 42a, as best shown in FIGs. 2-5. In certain FIGs., the tabbing ribbon 42 is only shown on one of the faces 38, 40 merely for the sake of orientation clarity.
[0028] The tabbing ribbon 42 may be formed from various conductive materials, such as metals, conducting polymers, or combinations thereof. Examples of other suitable materials include those described in the incorporated references. The tabbing ribbon 42 is useful for connecting the PV cells 36 together, as well as to other components such as to bussing (not shown), other modules 20, etc. The PV cells 36 may be connected by the tabbing ribbon 42 in series or in parallel. The tabbing ribbons 42 are typically connected to bussing (not shown) for establishing a circuit and carrying energy collected by the PV cells 36.
[0029] While called tabbing "ribbon" 42, the tabbing ribbon 42 may be of various shapes and sizes, and may also be referred to in the art as tabbing, bussing, wire, or leads, depending on shape, size, location, etc. The tabbing ribbon 42 can be of various dimensions, such as from about 0.125 to about 2 mm in thickness and/or width on average.
[0030] At least one polymeric strip 44 is disposed between the substrate 24 and the PV cell 36. The polymeric strip 44 is adjacent the tabbing ribbon 42. The polymeric strip 44 is useful for protecting the tabbing ribbon 42 from the front face 26 of the substrate 24. Typically, the module 20 includes a plurality of polymeric strips 44. For example, as shown in FIGs. 2-5, the module 20 includes a first polymeric strip 44a and a second polymeric strip 44b spaced from the first polymeric strip 44a. The first polymeric strip 44a is typically disposed adjacent the first tabbing ribbon 42a and the second polymeric strip 44b is typically disposed adjacent the second tabbing ribbon 42b. The polymeric strips 44 are formed from a first polymeric composition. As shown generally, the polymeric strips 44 are spaced horizontally and side-by-side. Further, the polymeric strips 44 are generally disposed parallel relative to the direction of the tabbing ribbons 42.
[0031] The first polymeric composition may be formed from various polymer compositions. Typically, the first polymeric composition is a silicone, more typically a silicone elastomer. Suitable silicones include branched and unbranched, more typically unbranched, oligomeric or polymeric organosiloxanes. Examples of suitable polymeric compositions include hydrosilylation-reaction, condensation-reaction, and hydrosilylation/condensation- reaction, curable silicone compositions.
[0032] In certain embodiments, the polymeric strips 44 are formed from a hydrosilylation- reaction curable silicone composition. In further embodiments, the first polymeric composition comprises a diorganopolysiloxane having alkenyl groups (e.g. vinyl groups), an organosilicon hydride having silicon-bonded hydrogen atoms reactive with the alkenyl groups of the diorganopolysiloxane, and a non-reactive organopolysiloxane. By "non- reactive", it is generally meant that the non-reactive organopolysiloxane does not react with the diorganopolysiloxane or the organosilicon hydride. Examples of suitable diorganopolysiloxanes, organosilicon hydrides, and non-reactive organopolysiloxanes, include those described in the incorporated references.
[0033] The diorganopolysiloxane and the organosilicon hydride will generally react in the presence of the non-reactive organopolysiloxane, and optionally, additional components, to form a silicone polymer. The non-reactive organopolysiloxane is useful for adjusting physical properties of the silicone polymer as described further below. Examples of suitable additive components, such as catalysts, include those described in the incorporated references.
[0034] In certain embodiments, the diorganopolysiloxane is a dimethylvinyl-terminated dimethyl siloxane, the organosilicon hydride is a hydrogen-terminated dimethyl siloxane, and the non-reactive organopolysiloxane is a polydimethylsiloxane (PDMS).
[0035] In a specific embodiment, the first polymeric composition includes, consists essentially of, or consists of: two different dimethylvinyl-terminated polydimethylsiloxanes; a dimethylhydrogen-terminated polydimethylsiloxane; and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule. Said another way, the polymeric strips 44 can be the reaction product of these components. The reaction can be catalyzed by a hydrosilylation catalyst, e.g. a platinum-ligand complex, which can be included in, or added to, the first polymeric composition. In this embodiment, the reaction typically occurs in the presence of a PDMS, which can also be included in, or added to, the first polymeric composition. If utilized, the PDMS is non-reactive, e.g. non- reactive toward the aforementioned reactants of the first polymeric composition. As alluded to above, inclusion of components, such as PDMS, is useful for adjusting physical properties of the reaction product.
[0036] In the aforementioned embodiments, the components of the first polymeric composition may be included in various amounts. Typically, the first polymeric composition includes greater than about 45, greater than about 50, greater than about 55, greater than about 60, or greater than about 65, parts by weight of the diorganopolysiloxane, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values. Typically, the first polymeric composition includes from about 2.5 to about 7.5, about 3 to about 7, or about 3.5 to about 6.5, parts by weight of the organosilicon hydride, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values. Typically, the first polymeric composition has from about 25 to about 65, or about 30 to about 60, parts by weight of the non-reactive organopolysiloxane, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.
[0037] The first polymeric composition may also be referred to in the art as an encapsulant composition. Specific examples of suitable encapsulant compositions suitable for use as the first polymeric composition are commercially available from Dow Corning Corporation of Midland, Ml, such as Dow Corning® PV-6100 Cell Encapsulant. Further examples of suitable encapsulant compositions include those described in the incorporated references, such as those described as the "silicone encapsulant" in the '277 application.
[0038] Referring to FIG. 2, in one embodiment, the polymeric strips 44 are disposed on the rear face 40 of the PV cell 36. The polymeric strips 44 encapsulate at least a portion of the tabbing ribbons 42 that are on the rear face 40. Typically, the polymeric strips 44 are in direct, e.g. physical, contact with the rear face 40 of the PV cell 36. In these embodiments, the polymeric strips 44 typically have a substantially parabolic-shaped cross-section. The polymeric strips 44 may also have different shapes, i.e., they need not be perfectly shaped parabolas as depicted.
[0039] Referring to FIG. 3, the polymeric strips 44 are disposed in line with the tabbing ribbons 42. Specifically, the first polymeric strip 44a is aligned with the first tabbing ribbon 42a and the second polymeric strip 44b is aligned with the second tabbing ribbon 42b.
[0040] Typically, the polymeric strips 44 extend laterally across the module 20 to a periphery of the module 20 on ends of the module 20. The polymeric strips 44 may be continuous or there may be gaps therebetween, such as between adjacent PV cells 36 where the tabbing ribbon 42 transitions from the rear face 40 to the front face 38 of the PV cells 36.
[0041] Referring to FIG. 4, in a related embodiment, the polymeric strips 44 are further disposed on the front face 26 of the substrate 24 opposite the tabbing ribbon 42. Said another way, the polymeric strips 44 are disposed between the front face 26 of the substrate 24 and the rear face 40 of the PV cell 36. In certain embodiments, the polymeric strips 44 are in direct contact with the rear face 40 of the PV cell 36 and/or are in direct contact with the front face 26 of the substrate 24. In these embodiments, the polymeric strips 44 typically have a substantially rectangular-shaped cross-section. The polymeric strips 44 may also have different shapes, i.e., they need not be perfectly shaped rectangles as depicted. For example, while the edges of the polymeric strips 44 are illustrated as being concave, the edges may be straight, convex, slanted, or a combination of shapes. [0042] Referring to FIG. 5, in another embodiment, the polymeric strips 44 are disposed on the front face 26 of the substrate 24 opposite the tabbing ribbon 42. Typically, the polymeric strips 44 are in contact with and/or encapsulate at least a portion of the tabbing ribbon 42. In certain embodiments, the polymeric strips 44 are in direct contact with the front face 26 of the substrate 24. In these embodiments, the polymeric strips 44 typically have a substantially parabolic-shaped cross-section. The polymeric strips 44 may also have different shapes, i.e., they need not be perfectly shaped parabolas as depicted.
[0043] The polymeric strips 44 can be of various thicknesses, such as from about 0.05 to about 0.75, about 0.125 to about 0.4, or about 0.125 to about 0.25, mm on average, or any range between the lowest and highest of these values. Typically, the thickness of the polymeric strips 44 is varied to minimize the amount of the first polymeric composition that is used, thereby reducing production costs of the module 20, and also to simultaneously minimize or prevent bottoming out of the PV cells 36 and/or the tabbing ribbon 42.
[0044] In this context, "bottoming out" refers to a situation where the PV cells 36 and/or the tabbing ribbon 42 would contact the substrate 24, which could cause damage. Such a situation can arise during manufacture and/or use of the module 20. This situation is undesirable. As such, the polymeric strips 44 are useful for cushioning and protecting the PV cells 36 and the tabbing ribbon 42 from the substrate 24 in situations where they could potential come into contact with one another.
[0045] Each of the polymeric strips 44 can be of various widths, such as from about 2 to about 25, about 3 to about 20, or about 6 to about 13, mm on average, or any range between the lowest and highest of these values. Width of the polymeric strips 44 may be uniform or may vary. Typically, as best shown in FIGs. 2-5, each of the polymeric strips 44 has a width less than the width of the one of the PV cells 36, but greater than a width of one of the tabbing ribbons 42.
[0046] As best shown in FIGs. 2, 4, and 5, a tie-layer 46 is disposed between the substrate 24 and the cover sheet 30. The tie-layer 46 is also disposed around the PV cells 36. The tie-layer 46 is useful for coupling the rear face 34 of the cover sheet 30 to the front face 26 of the substrate 24. The tie-layer 46 is also useful for coupling the front face 38 of the PV cell 36 to the rear face 34 of the cover sheet 30. As used herein, "coupling" generally means physically connecting, unless indicated otherwise. The tie-layer 46 may also be referred to in the art as a polymeric tie-layer 46.
[0047] The tie-layer 46 is formed from a second polymeric composition. The second polymeric composition of the tie-layer 46 is different from the first polymeric composition of the polymeric strips 44. The first and second polymeric compositions can be different in various ways, such as being chemically and/or physically different. Typically, the first and second polymeric compositions are different in such a way to provide different moduli of elasticity. Examples of differences are described below.
[0048] The second polymeric composition may be formed from various polymer compositions. Typically, the second polymeric composition is a silicone, more typically a silicone elastomer. Examples of suitable polymeric compositions include hydrosilylation- reaction, condensation-reaction, and hydrosilylation/condensation-reaction, curable silicone compositions.
[0049] In certain embodiments, the tie-layer 46 is formed from a hydrosilylation-reaction curable silicone composition. In further embodiments, the second polymeric composition comprises a diorganopolysiloxane having alkenyl groups (e.g. vinyl groups), and an organosilicon hydride having silicon-bonded hydrogen atoms reactive with the alkenyl groups of the diorganopolysiloxane. Examples of suitable diorganopolysiloxanes, organosilicon hydrides, and non-reactive organopolysiloxanes include those described in the incorporated references.
[0050] The diorganopolysiloxane and the organosilicon hydride will generally react, optionally, in the presence of additional components, to form a silicone polymer. Examples of suitable additive components, such as catalysts, include those described in the incorporated references.
[0051] In certain embodiments, the diorganopolysiloxane is a dimethylvinyl-terminated dimethyl siloxane, and the organosilicon hydride is a hydrogen -terminated dimethyl siloxane. As introduced above, the second polymeric composition is different than the first polymeric composition. An example of a difference between the first and second polymer compositions is the inclusion of the non-reactive organopolysiloxane in the first polymeric composition while the second polymeric composition excludes the non-reactive organopolysiloxane.
[0052] In a specific embodiment, the second polymeric composition includes, consists essentially of, or consists of: a dimethylvinyl-terminated polydimethylsiloxane; a dimethylhydrogen-terminated polydimethylsiloxane; and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule. Said another way, the tie-layer 46 can be the reaction product of these components. The reaction can be catalyzed by a hydrosilylation catalyst, e.g. a platinum-ligand complex, which can be included in, or added to, the second polymeric composition.
[0053] In the aforementioned embodiments, the components of the second polymeric composition may be included in various amounts. Typically, the second polymeric composition includes greater than about 55, greater than about 60, or greater than about 65, parts by weight of the diorganopolysiloxane, each based on 100 parts by weight of the second polymeric composition, or any range between the lowest and highest of these values. Typically, the second polymeric composition includes from about 5 to about 25, about 5 to about 20, or about 8 to about 22.5, parts by weight of the organosilicon hydride, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.
[0054] The second polymeric composition may also include additional components, such as silanes or siloxanes. Such components can be included in various amounts. In certain embodiments, the second polymeric composition further comprises an organosilane and/or a dimethyl methylhydrogen siloxane. Such components can be included in various amounts, such as less than about 5 parts by weight, or from about 0.1 to about 2.5 parts by weight, each based on 100 parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
[0055] In another specific embodiment, the second polymeric composition includes, consists essentially of, or consists of: a dimethylvinyl-terminated polydimethylsiloxane; and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule. Said another way, the tie-layer 46 can be the reaction product of these components. The reaction can be catalyzed by a hydrosilylation catalyst, e.g. a platinum- ligand complex, which can be included in, or added to, the second polymeric composition.
[0056] In the aforementioned embodiment, the components of the second polymeric composition may be included in various amounts. Typically, the second polymeric composition includes from about 80 to about 99.9, about 90 to about 99.9, or about 95 to about 99.9, parts by weight of a dimethylvinyl-terminated polydimethylsiloxane (e.g. a dimethyl siloxane, dimethylvinylsiloxy-terminated polymer), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values. Typically, the second polymeric composition includes from about 0.01 to about 2, about 0.05 to about 1 , or about 0.05 to about 0.5, parts by weight of a platinum-ligand complex (e.g. 1 ,3-diethenyl-1 ,1 ,3,3-tetramethyldisiloxane complex (Pt)), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values. Typically, the second polymeric composition includes from about 0.01 to about 7.5, about 0.1 to about 5, or about 0.2 to about 2.5, parts by weight of an alkoxysilane (e.g. methacryloxypropyltrimethoxysilane), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values. Typically, the second polymeric composition includes from about 0.05 to about 7.5, about 0.1 to about 5, or about 0.5 to about 2.5, parts by weight of a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule (e.g. dimethyl, methylhydrogen siloxane, trimethylsiloxy-terminated), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values. Typically, the second polymeric composition includes from about 0.001 to about 2.5, about 0.005 to about 1 , or about 0.005 to about 0.5, parts by weight of a siloxane (e.g. tetramethyltetravinylcyclotetrasiloxane), each based on 100 parts by parts by weight of the second polymeric composition, or any range between the lowest and highest of these values.
[0057] The second polymeric composition may also be referred to in the art as an encapsulant composition. Specific examples of suitable encapsulant compositions suitable for use as the second polymeric composition are commercially available from Dow Corning Corporation, such as Dow Corning® PV-6150 Cell Encapsulant. Further examples of suitable encapsulant compositions include those described in the incorporated references, such as those described as the "silicone tie layer" in the '277 application.
[0058] The tie-layer 46 can be of various thicknesses, such as from about 0.125 to about 1 .25, about 0.25 to about 0.5, or about 0.3 to about 0.4, mm on average, or any range between the lowest and highest of these values. Thickness of the tie-layer 46 is generally defined between the cover sheet 30 and the substrate 24. Thickness can also be defined by one or more intermediate layers, if present. The intermediate layers are described below. Typically, the thickness of the tie-layer 46 is varied to minimize the amount of the second polymeric composition that is used, thereby reducing production costs of the module 20, and also to simultaneously minimize or prevent bottoming out of the PV cells 36 and/or the tabbing ribbon 42. Width of the tie-layer 46 is equal to or approaching the width of the module 20. As illustrated in the figures, the width of each of the polymeric strips 44 is less than the width of the tie-layer 46.
[0059] In this context, "bottoming out" refers to a situation where the PV cells 36 and/or the tabbing ribbon 42 would contact the cover sheet 30 and/or the substrate 24 which could cause damage. Such a situation can arise during manufacture and/or use of the module 20. This situation is undesirable. As such, the tie-layer 46 is useful for cushioning and protecting the PV cells 36 and the tabbing ribbon 42.
[0060] Typically, the tie-layer 46 is sandwiched between the cover sheet 30 and the substrate 24 as best illustrated in FIGs. 2, 4, and 5; however, there may be at least one intervening layer (not shown) between the tie-layer 46 and the cover sheet 30 and/or between the tie-layer 46 and the substrate 24. For example, there may be an intervening layer disposed between the tie-layer 46 and the substrate 24. Such an intervening layer is useful for thickness control and module 20 strength. An example of suitable intervening layer, is a nonwoven fiberglass (FG) layer. If included, the intervening layer may also be formed from other materials, such as PET, nylon, or silicone. In certain embodiments (not shown), the module 20 includes a nonwoven FG layer disposed between the substrate 24 and the tie-layer 46. In other embodiments, the module 20 is free of the intervening layer(s).
[0061] Typically, the modulus of elasticity of the tie-layer 46 is greater than the modulus of elasticity of the polymeric strips 44. In other words, the polymeric strips 44 are generally softer than the tie-layer 46. In these embodiments, having different moduli is useful for protecting the PV cells 36 and the tabbing ribbon 42 as described above. As alluded to above, the moduli can vary depending on the type of first and second polymeric compositions utilized. In certain embodiments, the shear modulus of elasticity of the tie- layer 46 is from about 15 to about 50, about 17.5 to about 40, or about 20 to about 30, kilopascals (kPa), and the shear modulus of elasticity of the polymeric strips 44 is from about 0.5 to about 12.5, about 1 to about 10, about 1 to about 7.5, about 1 to about 5, or about 1 to about 3, kPa, or any range between the lowest and highest of these values. In other embodiments, the shear modulus of elasticity of the tie-layer 46 is from about 50 to about 2000, about 50 to about 1750, about 50 to about 1500, about 50 to about 1250, about 50 to about 1000, about 50 to about 750, about 75 to about 600, about 100 to about 500, about 150 to about 450, about 200 to about 400, or about 200 to about 300, kPa, and the shear modulus of elasticity of the polymeric strips 44 is as just described, or any range between the lowest and highest of these values. As described above, it is believed that the modulus of elasticity of the tie-layer 46 helps to maintain orientation of the PV cells 36 when the module 20 is exposed to changes in temperature (e.g. during thermo-cycling, expansion/contraction, etc.).
[0062] The module 20 can be of various shapes, sizes, and configurations. In certain embodiments, the module 20 has a length of from about 1 .6 to about 2.0 and a width of from about 0.7 to about 1 .1 , meters (m) or any range between the lowest and highest of these values. The module 20 is not limited to any particular shape, length or width.
[0063] In further embodiments (not shown), the module 20 can further include "polymeric strips" as described in U.S. Pat. App. Ser. No. 61 /590996 (Attorney Docket No. DC1 1204 PSP1 ; 071038.00786), and/or a "peripheral tie-layer" as described in U.S. Pat. App. Ser. No. 61 /591005 (Attorney Docket No. DC1 1205 PSP1 ; 071038.00787), the disclosures of which are incorporated by reference in their entirety to the extent they do not conflict with the general scope of the present invention. If any conflict exists between the instant disclosure and any of the incorporated reference(s), only the portion(s) of any of the incorporated reference(s) that are in conflict with the instant disclosure, rather than an entirety of any of the incorporated reference(s), are expunged from incorporation herein from the incorporated reference(s). In yet further embodiments (not shown), the module 20 can include additional components, e.g. at least one spacer disposed along the perimeter. Such components are described in the incorporated references.
[0064] The invention method of forming the invention module 20 comprises the step of applying the first polymeric composition on the front face 26 of the substrate 24 and/or the rear face 40 of the PV cell 36 to form the polymeric strip 44 on the face(s) 26, 40. Specifically, in certain embodiments, such as illustrated in FIGs. 5 and 7, the first polymeric composition is applied on the front face 26 of the substrate 24 to form the polymeric strip 44. In other embodiments, such as illustrated in FIGs. 2, 4, 6, and 8, the first polymeric composition is applied on the rear face 40 of the PV cell 36 to form the polymeric strip 44, or a portion thereof as described immediately hereafter. Specifically, in related embodiments, such as illustrated in FIGs. 4 and 6, the first polymeric composition is also applied on the front face 26 of the substrate 24 to form the polymeric strip 44, in addition to the rear face 40 of the PV cell 36, to further form a remaining portion of the polymeric strip 44.
[0065] At this application stage, the polymeric strip 44 is generally in an uncured state, e.g. liquid form, to promote ease of application. However, the first polymeric composition generally has enough body to prevent flow off of the face(s) 26, 40 and/or to generally maintain shape of the polymeric strip 44. The first polymeric composition can be applied to the face(s) 26, 40 by various means, such as by spraying, dispensing, flow coating, injecting, etc. In other embodiments, the polymeric strips 44 are pre-formed and disposed on the face(s) 26, 40 of the PV cell 36. For example, a polymeric sheet can be made from the first polymeric composition and cut into the polymeric strips 44, or the polymeric strips can be pre-made from the first polymeric composition and disposed on the face(s) 26, 40 of the PV cell 36. In certain embodiments, the first polymeric composition is dispensed (or disposed) on the face(s) 26, 40 robotically.
[0066] As shown in FIG. 6, a robotic dispenser 48a is shown applying the first polymeric composition to the substrate 24 and to the PV cell 36. As shown in FIG. 7, the robotic dispenser 48a is shown applying the first polymeric composition just to the substrate 24. As shown in FIG. 8, the robotic dispenser 48a is shown applying the first polymeric composition just to the PV cell 36. The robotic dispenser 48a typically has one or more nozzles 50, from which the first polymeric composition dispenses. The nozzles 50 can be selectively turned on or off to provide polymeric strips 44 of various widths. As such, one or more nozzles 50 may be used to form each of the polymeric strips 44. The polymeric strips 44 may be formed separately or simultaneously, i.e., at the same or at different times. The robotic dispenser 48a can be on a track and/or arm (not shown) and programmed to move along the length and/or width of the substrate 24 and/or PV cell 36 to form the polymeric strips 44. In the alternative, the substrate 24 and/or PV cell 36 can also be moved relative to the robotic dispenser 48a, or both can move relative to each other.
[0067] The first polymeric composition can be applied to the face(s) 26, 40 in various amounts. For example, the first polymeric composition can be applied such that the polymeric strips 44 each have a width of from about 5 to about 13 mm on average and a thickness of from about 0.125 to about 0.75 mm on average, or any range between the lowest and highest of these values. If portions of the polymeric strips 44 are applied to each of the faces 26, 40, each of the portions may be of the same or different thickness. In these embodiments, the thicknesses of each of the portions collectively define the thickness of the polymeric strips 44 as described above. For example, as shown in FIG. 6, the polymeric strips 44 are formed from two portions.
[0068] The method further comprises the step of applying the second polymeric composition to the rear face 34 of the cover sheet 30 to form the tie-layer 46, or a portion thereof as described below. At this application stage, the tie-layer 46 is generally in an uncured state, e.g. liquid form, to promote ease of application. However, the second polymeric composition generally has enough body to prevent flowing off of the rear face 34 and/or to generally maintain the shape of the tie-layer 46. The second polymeric composition can be applied to the rear face 34 by various means, such as by spraying, dispensing, flow coating, injecting, etc. In certain embodiments, the second polymeric composition is dispensed on the rear face 34 robotically.
[0069] As shown in FIGs. 6 and 8, a robotic dispenser 48b is shown applying the second polymeric composition to the cover sheet 30 and to the PV cell 36 and polymeric strips 44. As shown in FIG. 7, the robotic dispenser 48b is shown applying the second polymeric composition to just the cover sheet 30 and PV cell 36. The robotic dispenser 48b can be the same as or different than the robotic dispenser 48a that applies the first polymeric composition. The robotic dispenser 48b can be on a track and/or arm (not shown) and programmed to move along the length and/or width of the cover sheet 30 and/or PV cell 36 to form the tie-layer 46. In the alternative, the cover sheet 30 and/or PV cell 36 can also be moved relative to the robotic dispenser 48b, or both can move relative to each other. The nozzles 50 can be selectively turned on or off to control application amount and location of the second polymeric composition.
[0070] The second polymeric composition can be applied in various amounts to form the tie-layer 46. Typically, the second polymeric composition is applied such that the tie-layer 46 has a thickness of from about 0.125 to about 1 .25 mm on average, or any range between these values.
[0071] After the second polymeric composition is applied to the cover sheet 30 to form the tie-layer 46, or a portion thereof, the PV cells 36 are disposed on the tie-layer 46. The PV cells 36 are disposed on the tie-layer 46 such that the rear faces 40 of the PV cells 36 are disposed opposite the cover sheet 30. The tie-layer 46 can be allowed to level prior to disposing the PV cells 36 to prevent gaps, voids, or other issues. The PV cells 36 may be disposed separately or simultaneously.
[0072] The PV cells 36 may be disposed by various means, such as by hand or by robotic grip 52a. The robotic grip 52a can use vacuum or other means to hold the PV cells 36. The robotic grip 52a can be operatively connected to a track and/or arm (not shown) for movement. The PV cells 36 can simply be placed on top of the tie-layer 46 or slightly pressed into the tie-layer 46. Pressing generally ensures that no gaps or voids are present between the tie-layer 46 and the PV cells 36.
[0073] The tie-layer 46, or a portion thereof, may be cured (to a final cure state or partially thereto) prior to or after the PV cells 36 are disposed. For example, the tie-layer 46 can be cured via oven prior to disposing the PV cells 36. Applying heat to the tie-layer 46 generally facilitates cure of the tie-layer 46 from an uncured state to a final cured state. The polymeric strips 44 can also be cured prior to the PV cells 36 being disposed, in addition or alternate to, the tie-layer 46 being cured. The tie-layer 46 can be cured prior to, after, or at the same time as the polymeric strips 44.
[0074] In certain embodiments, a third polymeric composition is applied over the PV cells 32 to fully encapsulate the PV cells 32 and to further form the tie-layer 46. Typically, the third polymeric composition is the same as the second polymeric composition, such as shown in FIGs. 6-8. In other embodiments (not shown), the third polymeric composition can be the same as the first polymeric composition, or can be different from both the first and second polymeric compositions. The third polymeric composition can be different in various ways, such as providing a modulus that falls between those provided by the first and second polymeric compositions, or a modulus that is less than or greater than those provided by the first and second polymeric compositions. The third polymeric composition can be applied as like described above with description of the first and second polymeric compositions, such as by the robotic dispenser 48. The third polymeric composition can be cured at various times. The third polymeric composition can be a silicone. The tie-layer 46 can be cured before or after application of the third polymeric composition, if employed.
[0075] After all of the polymeric compositions are applied, the substrate 24 and the cover sheet 30 are combined to form the module 20. The substrate 24 and cover sheet 30 can be combined in various ways. For example, the substrate 24 can be laid over the tie-layer 46 to form the module 20. As shown in FIGs. 6-8, the substrate 24 and cover sheet 30 can be pressed together to form the module 20. A robotic grip 52b can be used for moving the substrate 24 and/or the cover sheet 30 into place; however, other means can also be used. The tie-layer 46 may also have portions formed from the third polymeric composition as described above (where the third is different than the first and second).
[0076] In certain embodiments, the tie-layer 46 is generally at a viscosity, at the time of combining the substrate 24 and the cover sheet 30, which allows for any air that may be trapped within/by the tie-layer 46 to migrate outwardly therefrom. In this way, bubbles are not formed and/or trapped, as bubbles could create issues for the module 20. The viscosity can be an initial viscosity of the second polymeric composition (i.e., pre-cure), or a higher viscosity that arises after at least partial cure of the tie-layer 46. While not required, these embodiments may be useful in instances where the module 20 is cured via a vacuum- press process.
[0077] The silicone composition used to form the tie-layer 46 typically has a complex (dynamic) viscosity of from 10,000 to 5,000,000 cPs at 25°C measured at 1 radian per second at 1 to 5% strain. More specifically, a Frequency Sweep is generated on a TA Instruments, HR-2 parallel plate Rheometer. A sample is loaded between two 25 mm parallel plates to a 2 mm thickness. The frequency sweep is run from 0.1 rad/sec to 100 rad/sec at a 5% strain, the dynamic (complex) viscosity is reported at 1 rad/sec in cP. In other embodiments, the complex viscosity is from 15,000 to 100,000, from 20,000 to 95,000, from 25,000 to 90,000, from 30,000 to 85,000, from 35,000 to 75,000, from 40,000 to 70,000, from 45,000 to 65,000, from 50,000 to 60,000, or from 55,000 to 60,000, cPs at 25°C measured as described above. In other embodiments, the complex viscosity is from 50,000 to 100,000, from 55,000 to 95,000, from 60,000 to 90,000, from 65,000 to 85,000, from 70,000 to 80,000, or from 75,000 to 80,000, cPs at 25°C measured as described above.
[0078] In still other embodiments, the complex viscosity is from 35,000 to 300,000, from 40,000 to 295,000, from 45,000 to 290,000, from 50,000 to 285,000, from 55,000 to 280,000, from 60,000 to 275,000, from 65,000 to 275,000, from 70,000 to 270,000, from 75,000 to 265,000, from 80,000 to 260,000, from 85,000 to 255,000, from 90,000 to 250,000, from 95,000 to 245,000, from 100,000 to 240,000, from 105,000 to 235,000, from 1 10,000 to 230,000, from 1 15,000 to 225,000, from 120,000 to 220,000, from 125,000 to 215,000, from 130,000 to 210,000, from 135,000 to 205,000, from 140,000 to 200,000, from 145,000 to 195,000, from 150,000 to 190,000, from 155,000 to 185,000, from 160,000 to 180,000, from 165,000 to 175,000, or from 165,000 to 170,000, from 80,000 to 200,000, from 40,000 to 200,000, or from 40,000 to 300,000, cPs at 25°C measured as described above.
[0079] In still other embodiments, the complex viscosity is from 100,000 to 1 ,000,000, from 125,000 to 975,000, from 150,000 to 950,000, from 175,000 to 925,000, from 200,000 to 900,000, from 225,000 to 875,000, from 250,000 to 850,000, from 275,000 to 825,000, from 300,000 to 800,000, from 325,000 to 775,000, from 350,000 to 750,000, from 375,000 to 725,000, from 400,000 to 700,000, from 425,000 to 675,000, from 450,000 to 650,000, from 475,000 to 625,000, from 500,000 to 600,000, from 525,000 to 575,000, or from 550,000 to 575,000, cPs at 25°C measured as described above.
[0080] In even further embodiments, the complex viscosity is from 1 ,125,000 to 1 ,975,000, from 1 ,150,000 to 1 ,950,000, f rom 1 ,175,000 to 1 ,925,000, f rom 1 ,200,000 to 1 ,900,000, from 1 ,225,000 to 1 ,875,000, f rom 1 ,250,000 to 1 ,850,000, f rom 1 ,275,000 to 1 ,825,000, from 1 ,300,000 to 1 ,800,000, f rom 1 ,325,000 to 1 ,775,000, f rom 1 ,350,000 to 1 ,750,000, from 1 ,375,000 to 1 ,725,000, f rom 1 ,400,000 to 1 ,700,000, f rom 1 ,425,000 to 1 ,675,000, from 1 ,450,000 to 1 ,650,000, f rom 1 ,475,000 to 1 ,625,000, f rom 1 ,500,000 to 1 ,600,000, from 1 ,525,000 to 1 ,575,000, f rom 1 ,550,000 to 1 ,575,000, f rom 2,125,000 to 2,975,000, from 2,150,000 to 2,950,000, f rom 2,175,000 to 2,925,000, f rom 2,200,000 to 2,900,000, from 2,225,000 to 2,875,000, f rom 2,250,000 to 2,850,000, f rom 2,275,000 to 2,825,000, from 2,300,000 to 2,800,000, f rom 2,325,000 to 2,775,000, f rom 2,350,000 to 2,750,000, from 2,375,000 to 2,725,000, f rom 2,400,000 to 2,700,000, f rom 2,425,000 to 2,675,000, from 2,450,000 to 2,650,000, f rom 2,475,000 to 2,625,000, f rom 2,500,000 to 2,600,000, from 2,525,000 to 2,575,000, f rom 2,550,000 to 2,575,000, f rom 3,125,000 to 3,975,000, from 3,150,000 to 3,950,000, f rom 3,175,000 to 3,925,000, f rom 3,200,000 to 3,900,000, from 3,225,000 to 3,875,000, f rom 3,250,000 to 3,850,000, f rom 3,275,000 to 3,825,000, from 3,300,000 to 3,800,000, f rom 3,325,000 to 3,775,000, f rom 3,350,000 to 3,750,000, from 3,375,000 to 3,725,000, f rom 3,400,000 to 3,700,000, f rom 3,425,000 to 3,675,000, from 3,450,000 to 3,650,000, f rom 3,475,000 to 3,625,000, f rom 3,500,000 to 3,600,000, from 3,525,000 to 3,575,000, f rom 3,550,000 to 3,575,000, f rom 4,125,000 to 4,975,000, from 4,150,000 to 4,950,000, from 4,175,000 to 4,925,000, from 4,200,000 to 4,900,000, from 4,225,000 to 4,875,000, from 4,250,000 to 4,850,000, from 4,275,000 to 4,825,000, from 4,300,000 to 4,800,000, from 4,325,000 to 4,775,000, from 4,350,000 to 4,750,000, from 4,375,000 to 4,725,000, from 4,400,000 to 4,700,000, from 4,425,000 to 4,675,000, from 4,450,000 to 4,650,000, from 4,475,000 to 4,625,000, from 4,500,000 to 4,600,000, from 4,525,000 to 4,575,000, or from 4,550,000 to 4,575,000, cPs at 25°C measured as described above.
[0081] Any one or more of the aforementioned values can be increased by an order of magnitude. As just one example, the silicone composition may have a complex viscosity of from 10,000 to 50,000,000 cPs at 25°C measured as described above. Any of the aforementioned values may, for example, vary by 1 , 2, 3, 4, 5, 10, 15, 20, or 25+ % in varying non-limiting embodiments. All values, and ranges of values, between and including the aforementioned values are also hereby expressly contemplated in various non-limiting embodiments. The aforementioned viscosity is the complex viscosity of the silicone composition before curing. After curing, the cured reaction product is typically a solid but may also be a gel.
[0082] In various embodiments, the second polymeric composition is applied in a pattern defining at least one passage (not shown) extending from an interior of module 20 to a perimeter of the module 20 to form the tie-layer 46. The pattern is not particularly limited and may be further described as a geometric, non-geometric, uniform or non-uniform pattern. In one embodiment, the silicone composition is deposited in one, two, or a plurality of rows. One or more of the rows may be disposed substantially parallel or traverse (i.e., at an angle) with one or more other rows. For example, the passages formed from the silicone composition may extend to opposing or different locations on the perimeter of the module 20. This may be achieved based on the disposition of the one or more rows of the silicone composition.
[0083] In other embodiments, patterning can be used for the first polymeric composition, in addition or alternate to the second polymeric composition. In general, patterning is useful for the more viscous/heavier of the two polymeric compositions. Further examples of suitable patterns/patterning methodology, as well as the benefits thereof, include those described in the incorporated '277 application.
[0084] The passage is also not particularly limited. Typically, the passage is defined on two or more sides by the deposition of the silicone composition. The passage may alternatively be described as a conduit, duct, fluting, furrow, gouge, groove, gutter, pass, passage, trough, channel, lane, opening, or pathway. [0085] The passage extends from an interior of the module 20 to the perimeter (e.g. an exterior) of the module 20 and may originate at any point on the interior of the module 20. The passage may extend across an entirety of the interior or across a portion of the interior. The passage may extend to two or more points on the perimeter of the module 20 or a single point. The passage may be further defined as one, two, or a plurality of individual passages that may be connected or not connected to each other in whole or in one or more parts. Air, e.g. from bubbles, may pass through the passage to the perimeter of the module 20 before the deposited silicone composition defining the passage merges together to fill in and thereby eliminate the passage. Typically, the passage is defined such that air can pass through the passage and exit the module 20 to reduce or eliminate the presence of any air bubbles in one or more layers, e.g. the tie-layer 46. Said differently, the passage typically allows air to flow from an interior of the module 20 (e.g. from a center), out towards a perimeter of the module 20 (e.g. to the edges), thereby minimizing the amount of air trapped in the module 20 in any one or more layers or components.
[0086] Pressure and/or heat can be applied to the module 20 for a period of time during and/or after combining the substrate 24 and the cover sheet 30 to further form the module 20. If both pressure and heat are employed, the pressure and heat can be applied separately or simultaneously. Application of heat is useful for curing the tie-layer 46 to a final cure state. These steps may be referred to in the art as press curing or lamination. Examples of suitable lamination techniques include vacuum or atmospheric lamination, and can include the application of heat. Specific examples of such processes, e.g. vacuum lamination, as well as other optional steps, are described in some of the incorporated references.
[0087] In certain embodiments, the module 20 is formed with application of heat. Suitable temperatures are of from about 20 to about 200, about 40 to about 150, or about 70 to about 1 10, °C, or any range between these values.
[0088] In certain embodiments, the module 20 is formed with application of pressure. For example, pressure can be applied to the module 20 via a flat plate press. Other apparatuses can also be used to apply pressure to form the module 20.
[0089] Suitable pressures are of from about7 to about 350, about 20 to about 200, or about 30 to about 140, kPa, or any range between these values. Various combinations of temperature and pressure can be used, or only one of temperature and pressure can be used to form the module 20. As described above, the polymeric strips 44 and/or the tie- layer 46 can be cured. Typically, at least the polymeric strips 44 are cured prior to pressing the module 20. [0090] Once the module 20 is formed by combination, typically, at least a portion of the tie- layer 46 that was disposed over the polymeric strips 44 laterally displaces as the substrate 24 and the cover sheet 30 are combined, e.g. pressed, to form the module 20. As also shown, the tie-layer 46 is sandwiched between the cover sheet 30 and the substrate 24 and the polymeric strips 44 are disposed adjacent the tabbing ribbon 42.
[0091] As introduced above, the polymeric strips 44 are useful for protecting the tabbing ribbon 42 and/or PV cells 36 from the front face 26 of the substrate 24. Said another way, the polymeric strips 44 can act as a spacer, which is useful during manufacture of the module 20.
[0092] Without being bound or limited by any particular theory, it is believed that when the polymeric strips 44 are aligned with the tabbing ribbon 42, the polymeric strips 44 provide a soft surface for the tabbing ribbon 42 to be pressed against when pressure is applied to the module 20. Providing such a soft surface or cushion, prevents the PV cells 36 from cracking. This is especially true when the substrate 24 and/or cover sheet 30 are both formed from glass, where the glass could potentially come into contact with the PV cells 36 but for the presence of the polymeric strips 44. As such, the polymeric strips 44 can also provide for a thinner tie-layer 46 relative to conventional tie-layers, especially between the substrate 24 and the PV cells 32. For example, less of the second polymeric compensation is required since the tie-layer 46 is not needed to act as a spacer, but rather, just as an encapsulant for the PV cells 36. It is also believed that the polymeric strips 44 provide for the exclusion of an intermediate layer (e.g. a nonwoven spacer) between the substrate 24 and the PV cells 36 since the polymeric strips 44 act as the spacer. While not necessary, the polymeric strips 44 should be cured prior to application of peak pressure to the module 20. The polymeric strips 44 can serve to protect even after manufacture of the module 20, such as during transport, installation, and/or use of the module 20.
[0093] One or more of the values described above may vary by ±5%, ±10%, ±15%, ±20%, ±25%, etc. so long as the variance remains within the scope of the disclosure. Unexpected results may be obtained from each member of a Markush group independent from all other members. Each member may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims. The subject matter of all combinations of independent and dependent claims, both single and multiple dependent, is herein expressly contemplated. The disclosure is illustrative including words of description rather than of limitation. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described herein.

Claims

CLAIMS What is claimed is:
1 . A photovoltaic (PV) cell module comprising:
a substrate having a front face and a rear face spaced from said front face of said substrate;
a cover sheet having a front face and a rear face spaced from said front face of said cover sheet;
at least one PV cell disposed between said substrate and said cover sheet with said PV cell having a front face and a rear face spaced from said front face of said PV cell; at least one tabbing ribbon disposed on said rear face of said PV cell;
at least one polymeric strip disposed between said substrate and said PV cell adjacent said tabbing ribbon for protecting said tabbing ribbon from said front face of said substrate with said polymeric strip formed from a first polymeric composition; and
a tie-layer disposed between said substrate and said cover sheet and around said PV cell for coupling said rear face of said cover sheet to said front face of said substrate and for coupling said front face of said PV cell to said rear face of said cover sheet with said tie-layer formed from a second polymeric composition different than said first polymeric composition of said polymeric strip.
2. The module as set forth in claim 1 wherein:
i) a modulus of elasticity of said tie-layer is greater than a modulus of elasticity of said polymeric strip;
ii) a modulus of elasticity of said tie-layer is from about 15 to about 50 kilopascals (kPa)and a modulus of elasticity of said polymeric strip is from about 0.5 to about 12.5 kPa;
iii) a modulus of elasticity of said tie-layer is from about 50 to about 2000 kilopascals (kPa) and a modulus of elasticity of said polymeric strip is from about 0.5 to about 12.5 kPa;
iv) both i) and ii); or
v) both i) and iii).
3. The module as set forth in claim 1 or 2, wherein said polymeric strip:
i) is disposed on said rear face of said PV cell and encapsulates at least a portion of said tabbing ribbon;
ii) is in direct contact with said rear face of said PV cell; and/or
iii) has a substantially parabolic-shaped cross-section.
4. The module as set forth in claim 3 wherein said polymeric strip:
i) is further disposed on said front face of said substrate opposite said tabbing ribbon,
ii) is in direct contact with said rear face of said PV cell and is in direct contact with said front face of said substrate; and/or
iii) has a substantially rectangular-shaped cross-section.
5. The module as set forth in claim 1 or 2, wherein said polymeric strip is:
i) disposed on said front face of said substrate opposite said tabbing ribbon; ii) in contact with and/or encapsulates at least a portion of said tabbing ribbon; iii) in direct contact with said front face of said substrate; and/or
iv) has a substantially parabolic-shaped cross-section.
6. The module as set forth in any one of the preceding claims, wherein said at least one tabbing ribbon is further defined as a first tabbing ribbon and a second tabbing ribbon spaced from said first tabbing ribbon.
7. The module as set forth in claim 6 wherein:
i) said at least one polymeric strip is further defined as a first polymeric strip and a second polymeric strip spaced from said first polymeric strip with said first polymeric strip disposed adjacent said first tabbing ribbon and said second polymeric strip disposed adjacent said second tabbing ribbon;
ii) said at least one polymeric strip is further defined as a first polymeric strip and a second polymeric strip spaced from said first polymeric strip with said first polymeric strip disposed adjacent said first tabbing ribbon and said second polymeric strip disposed adjacent said second tabbing ribbon, and wherein said polymeric strips are disposed on said rear face of said PV cell with said first polymeric strip encapsulating at least portion of said first tabbing ribbon and said second polymeric strip encapsulating at least a portion of said second tabbing ribbon; or
iii) said at least one polymeric strip is further defined as a first polymeric strip and a second polymeric strip spaced from said first polymeric strip with said first polymeric strip disposed adjacent said first tabbing ribbon and said second polymeric strip disposed adjacent said second tabbing ribbon, wherein said polymeric strips are disposed on said rear face of said PV cell with said first polymeric strip encapsulating at least portion of said first tabbing ribbon and said second polymeric strip encapsulating at least a portion of said second tabbing ribbon, and wherein said first polymeric strip is further disposed on said front face of said substrate opposite said first tabbing ribbon and said second polymeric strip is further disposed on said front face of said substrate opposite said second tabbing ribbon.
8. The module as set forth in claim 6 wherein said at least one polymeric strip is further defined as a first polymeric strip and a second polymeric strip spaced from said first polymeric strip with said first polymeric strip disposed adjacent said first tabbing ribbon and said second polymeric strip disposed adjacent said second tabbing ribbon and wherein: i) said first polymeric strip is disposed on said front face of said substrate opposite said first tabbing ribbon and said second polymeric strip is disposed on said front face of said substrate opposite said second tabbing ribbon; or
ii) said first polymeric strip is disposed on said front face of said substrate opposite said first tabbing ribbon and said second polymeric strip is disposed on said front face of said substrate opposite said second tabbing ribbon, and wherein said first polymeric strip is in contact with and/or encapsulates at least a portion of said first tabbing ribbon and said second polymeric strip is in contact with and/or encapsulates at least a portion of said second tabbing ribbon.
9. The module as set forth in any one of the preceding claims, wherein:
i) each of said polymeric strip(s) has a thickness of from about 0.125 to about 0.75 mm on average and a width of from about 5 to about 13 mm on average; and/or
ii) said tie-layer has a thickness of from about 0.25 to about 1 .25 mm on average.
10. The module as set forth in any one of the preceding claims, wherein said:
i) cover sheet is formed from glass; and/or
ii) substrate is formed from glass, a polymeric material, or a composite material.
1 1 . The module as set forth in any one of the preceding claims, wherein said:
i) first polymeric composition comprises greater than about 45 parts by weight of a diorganopolysiloxane having alkenyl groups, from about 2.5 to about 7.5 parts by weight of an organosilicon hydride having silicon-bonded hydrogen atoms reactive with said diorganopolysiloxane, and from about 25 to about 65 parts by weight of a non-reactive organopolysiloxane, each based on 100 parts by weight of said first polymeric composition; and/or
ii) second polymeric composition comprises greater than about 55 parts by weight of a diorganopolysiloxane having alkenyl groups and from about 5 to about 25 parts by weight of an organosilicon hydride having silicon-bonded hydrogen atoms reactive with said diorganopolysiloxane, each based on 100 parts by weight of said second polymeric composition.
12. The module as set forth in any one of claims 1 -1 1 , wherein:
I) said first polymeric composition comprises:
two different dimethylvinyl-terminated polydimethylsiloxanes; a dimethylhydrogen-terminated polydimethylsiloxane; and
a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule;
II) said second polymeric composition comprises:
i) a dimethylvinyl-terminated polydimethylsiloxane, a dimethylhydrogen-terminated polydimethylsiloxane, and a trimethylsiloxy- terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule; or
ii) a dimethylvinyl-terminated polydimethylsiloxane, and a trimethylsiloxy-terminated dimethyl methylhydrogen siloxane containing at least 3 SiH units per molecule; or
III) both I) and II).
13. A method of forming a photovoltaic (PV) cell module comprising a substrate having a front face and a rear face spaced from the front face of the substrate, a cover sheet having a front face and a rear face spaced from the front face of the cover sheet, at least one PV cell disposed between the substrate and the cover sheet with the PV cell having a front face and a rear face spaced from the front face of the PV cell, at least one tabbing ribbon disposed on the rear face of the PV cell, at least one polymeric strip disposed between the substrate and the PV cell adjacent the tabbing ribbon, and a tie-layer disposed between the substrate and the cover sheet and around the PV cell for coupling the rear face of the cover sheet to the front face of the substrate, said method comprising the steps of:
applying a first polymeric composition on i) the front face of the substrate and/or ii) the rear face of the PV cell to form the at least one polymeric strip on the front face of the substrate and/or the rear face of the PV cell in an uncured state;
optionally, curing the at least one polymeric strip to a cured state;
applying a second polymeric composition different than the first polymeric composition on the ii) rear face of the cover sheet to form the tie-layer in an uncured state; optionally, curing the tie-layer to a cured state; disposing the PV cell on the tie-layer such that the rear face of the PV cell is disposed opposite the cover sheet; and
combining the substrate and the cover sheet to form the PV cell module such that the tie-layer is sandwiched between the cover sheet and the substrate and the at least one polymeric strip is disposed adjacent the tabbing ribbon for protecting the tabbing ribbon from the front face of the substrate.
14. The method as set forth in claim 13 wherein the first polymeric composition is: a) applied on i) the front face of the substrate to form the at least one polymeric strip and/or
b) applied on ii) the rear face of the PV cell to form the at least one polymeric strip.
15. The method as set forth in claim 13 or 14, wherein :
a) the at least one polymeric strip is cured prior to combining the substrate and the cover sheet; and/or
b) the tie-layer is cured prior to disposing the PV cell.
16. The method as set forth in any one of claims 13-15, further comprising the step(s) of:
applying pressure to the PV cell module for a period of time during and/or after combining the substrate and the cover sheet to further form the PV cell module; and/or applying heat to the PV cell module for a period of time during and/or after combining the substrate and the cover sheet to further form the PV cell module.
17. The method as set forth in any one of claims 13-16, wherein the steps of:
a) applying are further defined as dispensing the polymeric compositions via a robotic dispenser; and/or
b) curing are further defined as applying heat to the tie-layer and/or the at least one polymeric strip for facilitating cure of the tie-layer and/or the at least one polymeric strip from the uncured state to the cured state.
18. The method as set forth in any one of claims 13-17, wherein the:
a) first polymeric composition is applied such that the at least one polymeric strip has a thickness of from about 0.125 to about 0.75 mm on average and a width of from about 5 to about 13 mm on average; and/or
b) second polymeric composition is applied such that tie-layer has a thickness of from about 0.25 to about 1 .25 mm on average.
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