WO2013112883A1

WO2013112883A1 - Method of forming a photovoltaic cell module

Info

Publication number: WO2013112883A1
Application number: PCT/US2013/023213
Authority: WO
Inventors: Barry M. KETOLA
Original assignee: Dow Corning Corporation
Priority date: 2012-01-26
Filing date: 2013-01-25
Publication date: 2013-08-01
Also published as: TW201347215A

Abstract

A method of forming a photovoltaic (PV) cell module comprises the step of applying a first polymeric composition around a periphery of i) a front face of a substrate and/or ii) a rear face of a cover sheet to form a peripheral tie-layer on the face(s). The method further comprises the step of applying a second polymeric composition, different than the first polymeric composition, to ii) the rear face of the cover sheet to form an inner tie-layer. The method further comprises the step of disposing a PV cell on the inner tie-layer formed from the application of the second polymeric composition. The method further comprises the step of combining the substrate and the cover sheet to form the PV cell module such that the peripheral tie-layer and the inner tie-layer are sandwiched between the substrate and the cover sheet with the PV cell encapsulated by the inner tie-layer.

Description

METHOD OF FORMING A PHOTOVOLTAIC CELL MODULE

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 61/591 ,005, filed on January 26th, 2012, which is incorporated herewith by reference in its entirety.

BACKGROUND

[0002] The present invention generally relates to a method of forming a photovoltaic (PV) cell module and to PV cell modules formed according to the invention method.

[0003] Solar or PV cells are semiconductor devices used to convert light into electricity. In many applications, the PV cells are encapsulated 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 silicone encapsulant can be used to completely encapsulate the PV cells within a module. Typically, a lamination method is used to form the module, such that the silicone encapsulant is cured between the cover sheet and the back sheet, with the PV cells encapsulated by the silicone encapsulant. In certain applications, both the cover and back sheets are formed from glass. A bladder press can be used for lamination to prevent damage to the sheets and to cure the silicone encapsulant.

[0004] Unfortunately, after pressure is released, the glass sheets tend to flex at the edges and corners, especially the back sheet, which can cause cohesive failure between the sheet(s) and the silicone encapsulant either immediately after relaxing the pressure, or sometime thereafter. Such cohesive failure can damage or distort the module, making it unsuitable for long term use, if usable at all. Accordingly, there remains an opportunity to provide improved methods of forming modules. There also remains an opportunity to provide improved modules, such as modules with improved cohesive strength and durability.

SUMMARY OF THE INVENTION

[0005] The present invention provides a method of forming a photovoltaic (PV) cell module. The invention module comprises a substrate having a front face and a rear face spaced from the front face. The module also comprises a cover sheet having a front face and a rear face spaced from the front face of the cover sheet. An inner tie-layer is disposed between the substrate and the cover sheet for coupling the rear face of the cover sheet to the front face of the substrate. The inner tie-layer has a surrounding edge. At least one PV cell is disposed within the inner tie-layer. A peripheral tie-layer is also disposed between the substrate and the cover sheet and peripherally disposed around the surrounding edge of the inner tie-layer for further coupling the rear face of the cover sheet to the front face of the substrate.

[0006] The invention method comprises the step of applying a first polymeric composition around a periphery of i) the front face of the substrate and/or ii) the rear face of the cover sheet to form the peripheral tie-layer on the face(s) in an uncured state. The method further comprises the step of applying a second polymeric composition different than the first polymeric composition to ii) the rear face of the cover sheet to form the inner tie-layer in an uncured state. The method further comprises the step of disposing the PV cell on the inner tie-layer formed from the application of the second polymeric composition. The method further comprises the step of combining the substrate and the cover sheet to form the module such that the peripheral tie-layer and the inner tie-layer are sandwiched between the substrate and the cover sheet with the PV cell(s) encapsulated by the inner tie-layer. 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 exploded cross-sectional side-view of an embodiment of the PV cell module including a PV cell;

[0010] FIG. 3 is a perspective view of a PV cell disposed on an inner tie-layer and between a peripheral tie layer;

[0011] FIG. 4 is a top down view of an embodiment of the PV cell module comprising a plurality of PV cells disposed within the inner tie-layer and between the peripheral tie-layer;

[0012] FIG. 5 is a broken cross-sectional schematic side-view illustrating application, disposing, and combining steps of an embodiment of the method; [0013] FIG. 6 is a broken cross-sectional schematic side-view illustrating additional amounts of polymeric compositions being applied over the PV cell and inner tie-layer to further form the inner and peripheral tie-layers;

[0014] FIG. 7 is a broken cross-sectional schematic side-view illustrating first and second polymeric compositions being applied to form the inner and peripheral tie-layers;

[0015] FIG. 8 is a broken cross-sectional schematic side-view illustrating the first polymeric composition being applied to form the peripheral tie-layer; and

[0016] FIG. 9 is a broken cross-sectional schematic side-view illustrating the second polymeric composition being applied to form the inner tie-layer.

DETAILED DESCRIPTION OF THE INVENTION

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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. The substrate 24 can be of various thicknesses, such as from about 0.05 to about 5, 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, the substrate 24 and the cover sheet 30 are both 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. 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.

[0024] The module 20 further comprises at least one PV cell 32. Typically, as like shown in FIG. 4, the module 20 includes a plurality of PV cells 32. The PV cells 32 are disposed between the substrate 24 and the cover sheet 30. The PV cells 32 are typically substantially coplanar with one another. The PV cells 32 can be arranged in various patterns, such as a series of PV cells 32 in a grid-like pattern (e.g. the pattern depicted in FIG. 4). The present invention is not limited to any particular pattern. The PV cells 32 may be offset from one another, such as in non-planar module 20 configurations. In certain embodiments, the PV cells 32 may be referred to in the art as crystalline silicon PV cells 32.

[0025] The PV cells 32 may be of various dimensions, be of various types, and be formed from various materials. Examples of suitable PV cells 32 include those described in the incorporated references. The PV cells 32 may be the same as or different from each other. The PV cells 32 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 32 can also be of various widths and lengths. Further examples of suitable PV cells 32 include those described in the incorporated references, such as those described in the '277 application.

[0026] As best shown in FIG. 4, tabbing ribbon 34 is disposed between the PV cells 32. The tabbing ribbon 34 is useful for establishing a circuit in the module 20. A series of two or more connected PV cells 32 may be referred to in the art as a string of cells. The tabbing ribbon 34 typically extends over upper and lower faces of the PV cells 32.

[0027] The tabbing ribbon 34 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 34 is useful for connecting the PV cells 32 together, as well as to other components such as to bussing (not shown), other modules 20, etc. The PV cells 32 may be connected by the tabbing ribbon 34 in series or in parallel. The tabbing ribbons 34 are typically connected to bussing (not shown) for establishing a circuit and carrying energy collected by the PV cells 32.

[0028] While called tabbing "ribbon" 34, the tabbing ribbon 34 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 34 can be of various dimensions, such as from about 0.125 to about 2 mm in thickness and/or width on average, or any range between these values.

[0029] The module 20 further comprises an inner tie-layer 36. The PV cells 32 are disposed within the inner tie-layer 36. Specifically, the PV cells 32 and tabbing ribbon 34 are encapsulated within the inner tie-layer 36. This is not to say that the PV cells 32 and/or tabbing ribbon 34 cannot be in physical or electrical contact with something outside of the inner tie-layer 36, such as a junction box or another module. The inner tie-layer 36 is disposed between the substrate 24 and the cover sheet 30 for coupling the rear face 34 of the cover sheet 30 to the front face 26 of the substrate 24. As used herein, "coupling" generally means physically connecting, unless indicated otherwise. The inner tie-layer 36 has a surrounding edge 38. The inner tie-layer 36 can be formed from one or more polymeric compositions as described below. The inner tie-layer 36 may also be referred to in the art as a polymeric inner tie-layer 36.

[0030] The inner tie-layer 36 can be of various thicknesses, such as from about 0.1 to about 1 .5, about 0.2 to about 0.75, or about 0.25 to about 0.5, mm on average, or any range between the lowest and highest of these values. Thickness of the inner tie-layer 36 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 inner tie-layer 36 is varied to minimize the amount of the 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 32 and/or the tabbing ribbon 34.

[0031] In this context, "bottoming out" refers to a situation where the PV cells 32 and/or the tabbing ribbon 34 would contact the cover sheet 30, 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 inner tie-layer 36 is useful for cushioning and protecting the PV cells 32 and the tabbing ribbon 34.

[0032] The module 20 further comprises a peripheral tie-layer 40. The peripheral tie-layer 40 is disposed between the substrate 24 and the cover sheet 30 and peripherally disposed around the surrounding edge 38 of the inner tie-layer 36 for further coupling the rear face 34 of the cover sheet 30 to the front face 26 of the substrate 24.

[0033] As best shown in FIG. 3, the peripheral tie-layer 40 typically abuts the surrounding edge 38 of the inner tie-layer 36. The peripheral tie-layer 40 can be disposed along two sides of the surrounding edge 38 as shown in FIG. 3, or along all four sides of the surrounding edge 38 as shown in FIG. 4. As such, the peripheral tie-layer 40 does not need to be completely disposed around the surrounding edge 38 of the inner tie-layer 36. The peripheral tie-layer 40 can be formed from one or more polymeric compositions as described below. The peripheral tie-layer 40 may also be referred to in the art as a polymeric peripheral tie-layer 40. While one simplified PV cell 32 is shown in FIG. 3, as well as a few of the other figures, the module 20 can include a plurality of PV cells 32.

[0034] The peripheral tie-layer 40 can be of various thicknesses, such as from about 0.1 to about 1 .5, about 0.2 to about 0.75, or about 0.25 to about 0.5, mm on average, or any range between the lowest and highest of these values. Thickness of the peripheral tie-layer 40 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. Typically, the thickness of the peripheral tie-layer 40 is varied to minimize the amount of the 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 32 and/or the tabbing ribbon 34.

[0035] In this context, "bottoming out" refers to a situation where the PV cells 32 and/or the tabbing ribbon 34 would contact the cover sheet 30, 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 peripheral tie-layer 40 is useful for cushioning and protecting the PV cells 32 and the tabbing ribbon 34. In addition, the peripheral tie-layer 40 can act as a spacer, which is useful during manufacture of the module 20, as described below.

[0036] The peripheral tie-layer 40 can be of various widths, such as from about 2.5 to about 155, about 6.5 to about 80, or about 12 to about 25, mm on average, or any range between the lowest and highest of these values. Width of the peripheral tie-layer 40 is generally defined between the surrounding edge 38 of the inner tie-layer 36 and an outer edge of the module 20. The width of the peripheral tie-layer 40 can be varied to minimize the amount of the polymeric composition that is used, thereby potentially reducing production costs of the module 20. However, the width of the peripheral tie-layer 40 should be sufficient to retain the polymeric composition(s) of the inner tie-layer 36 during at least manufacture of the module 20, and/or to sufficiently act as a spacer, as described below.

[0037] As alluded to above, the peripheral tie-layer 40 is formed from a first polymeric composition and the inner tie-layer 36 is formed from a second polymeric composition different than the first polymeric composition. 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. [0038] 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.

[0039] In certain embodiments, the peripheral tie-layer 40 is 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), 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.

[0040] 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.

[0041] 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 first 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 second polymeric composition (described below) while the first polymeric composition excludes the non-reactive organopolysiloxane.

[0042] In a specific embodiment, the first 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 peripheral tie-layer 40 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.

[0043] 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 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 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.

[0044] The first polymeric composition may also include additional components, such as silanes or siloxanes. Such components can be included in various amounts. In certain embodiments, the first 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, or from about 0.1 to about 2.5, parts by weight, each based on 100 parts by weight of the first polymeric composition, or any range between the lowest and highest of these values.

[0045] In another specific embodiment, the first 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 peripheral tie-layer 40 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.

[0046] In the aforementioned embodiment, the components of the first polymeric composition may be included in various amounts. Typically, the first 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 first polymeric composition, or any range between the lowest and highest of these values. Typically, the first 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 first polymeric composition, or any range between the lowest and highest of these values. Typically, the first 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 first polymeric composition, or any range between the lowest and highest of these values. Typically, the first 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 first polymeric composition, or any range between the lowest and highest of these values. Typically, the first 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 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. Examples of suitable encapsulant compositions, e.g. silicone compositions, include those described in the incorporated references. 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-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.

[0047] Referring to the second polymeric composition, 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.

[0048] In certain embodiments, the inner tie-layer 36 is formed from a hydrosilylation- reaction curable composition. In further embodiments, the second 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.

[0049] 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. [0050] 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).

[0051] In a specific embodiment, the second 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 inner tie-layer 36 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. In this embodiment, the reaction typically occurs in the presence of a PDMS, which can also be included in, or added to, the second polymeric composition. If utilized, the PDMS is non- reactive, e.g. non-reactive toward the aforementioned reactants of the second polymeric composition. As alluded to above, inclusion of components, such as PDMS, is useful for adjusting physical properties of the reaction product.

[0052] 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 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 second polymeric composition, or any range between the lowest and highest of these values. Typically, the second 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 second polymeric composition, or any range between the lowest and highest of these values. Typically, the second 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 second polymeric composition, or any range between the lowest and highest of these values.

[0053] 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-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. [0054] Typically, the modulus of elasticity of the inner tie-layer 36 is less than the modulus of elasticity of the peripheral tie-layer 40. In other words, the inner tie-layer 36 is generally softer than the peripheral tie-layer 40. In these embodiments, having different moduli is useful for protecting the PV cells 32 and the tabbing ribbon 34 as described above. In addition, peripheral tie-layer 40 can act as a spacer, as introduced above and described below. As alluded to above, the moduli can vary depending on the type of first and second polymeric compositions utilized.

[0055] In certain embodiments, the shear modulus of elasticity of the peripheral tie-layer 40 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 inner tie-layer 36 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 peripheral tie-layer 40 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 inner tie-layer 36 is as just described, or any range between the lowest and highest of these values. In yet other embodiments, the peripheral tie-layer 40 and inner tie-layer 36 both have a shear modulus of elasticity of 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, or any range between the lowest and highest of these values. In these embodiments, the peripheral tie-layer 40 can first be formed, i.e., cured, to subsequently retain the inner tie- layer 36 while still in a wet or pre-cured state. As described above, it is believed that the modulus of elasticity of the inner tie-layer 36 helps to maintain orientation of the PV cells 32 when the module 20 is exposed to changes in temperature (e.g. during thermo-cycling, expansion/contraction, etc.).

[0056] As introduced above, there may be at least one intervening layer (not shown) between the inner tie-layer 36 (and optionally, the peripheral tie-layer 40) and the cover sheet 30 and/or between the inner tie-layer 36 (and optionally, the peripheral tie-layer 40) and the substrate 24. For example, there may be an intervening layer disposed between the inner and peripheral tie-layers 36, 40 and the substrate 24. Such an intervening layer is useful for thickness control and strength of the module 20. An example of a 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 inner and peripheral tie-layers 36, 40. The module 20 does not need to include such an intervening layer.

[0057] 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.

[0058] 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 "polymeric strips" as described in U.S. Pat. App. Ser. No. 61 /591000 (Attorney Docket No. DC1 1226 PSP1 ; 071038.0081 1 ), 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).

[0059] The invention method of forming the invention module 20 comprises the step of applying the first polymeric composition around a periphery of the front face 26 of the substrate 24 and/or the rear face 34 of the cover sheet 30 to form the peripheral tie-layer 40 on the face(s) 26, 34. Specifically, in certain embodiments, the first polymeric composition is applied around the periphery of the front face 26 of the substrate 24 to form the peripheral tie-layer 40. In other embodiments, the first polymeric composition is applied around the periphery of the rear face 34 of the cover sheet 30 to form the peripheral tie- layer 40, or a portion thereof as described immediately hereafter. Specifically, in further embodiments, the first polymeric composition is also applied around the periphery of the front face 30 of the substrate 24, in addition to the rear face 34 of the cover sheet 30, to further form a remaining portion of the peripheral tie-layer 40.

[0060] At this application stage, the peripheral tie-layer 40 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, 34 and/or to generally maintain shape of the peripheral tie-layer 40. The first polymeric composition can be applied to the face(s) 26, 34 by various means, such as by spraying, dispensing, flow coating, injecting, etc. [0061] In other embodiments, the peripheral tie-layer 40, or portions thereof, is/are preformed and disposed on the face(s) 26, 34. For example, a polymeric sheet can be made from the first polymeric composition and cut into strips to form the peripheral tie-layer 40, or the strips can be pre-made from the first polymeric composition and disposed on the face(s) 26, 34 to form the peripheral tie-layer 40. In these or other embodiments, both the peripheral tie-layer 40 and the inner tie-layer 36 can be formed from the first polymeric composition, second polymeric composition, or a combination thereof. However, the peripheral tie-layer 40 is typically formed (or disposed) prior to the inner tie-layer 36 such that the peripheral tie-layer 40 can retain the inner tie-layer 36 while still in a wet or pre- cured state. For example, inner tie-layer 36 can be formed via patterning and/or rows of polymeric composition, as described further below. In certain embodiments, the first polymeric composition is dispensed (or disposed) on the face(s) 26, 34 robotically.

[0062] As shown in FIG. 5, a robotic dispenser 42 is shown applying the first polymeric composition to both the cover sheet 30 and the substrate 24. As described above, the first polymeric composition may also be applied to just the cover sheet 30 or the substrate 24, such as shown in FIG. 7. The robotic dispenser 42 typically has one or more nozzles 44, from which the first polymeric composition dispenses. The nozzles 44 can be selectively turned on or off to provide peripheral tie-layers 40 of various widths. The nozzles 44 can also be controlled to provide peripheral tie-layers 40 of various thicknesses, such as shown in FIG. 7. As such, one or more nozzles 44 may be used to form the peripheral tie-layer 40. Each portion of the peripheral tie-layer 40 may be formed separately or simultaneously, i.e., at the same or at different times. The robotic dispenser 42 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/substrate 24 to form the peripheral tie-layer 40. In the alternative, the cover sheet 30/substrate 24 can also be moved relative to the robotic dispenser 42, or both can move relative to each other.

[0063] The first polymeric composition can be applied to the face(s) 26, 34 in various amounts. For example, the first polymeric composition can be applied such that the peripheral tie-layer 40 has a width of from about 2.5 to about 150 mm on average and a thickness of from about 0.25 to about 1 .25 mm on average, or any range between the lowest and highest of these values. If portions of the peripheral tie-layer 40 are applied to each of the faces 26, 34, 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 peripheral tie-layer 40 as described above. For example, as shown in FIG. 5, the peripheral tie-layer 40 is formed from two portions. [0064] 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 inner tie-layer 36, or a portion thereof as described below. At this application stage, the inner tie-layer 36 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. 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.

[0065] As shown in FIG. 5, a robotic dispenser 42 is shown applying the second polymeric composition to both the cover sheet 30 and the substrate 24. The portions of the inner tie- layer 36 may be of the same or different thickness. In certain embodiments, the portion of the inner tie-layer 36 between the PV cells 32 and the substrate 24 is thinner than the portion between the PV cells 32 and the cover sheet 30. As described above, the second polymeric composition may also be applied to just the cover sheet 30. The robotic dispenser 42 typically has one or more nozzles 44, from which the first polymeric composition dispenses. The nozzles 44 can be selectively turned on or off to provide inner tie-layers 36 of various thicknesses. One or more nozzles 44 may be used to form the inner tie-layer 36. The robotic dispenser 42 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/substrate 24 to form the inner tie-layer 36. In the alternative, the cover sheet 30/substrate 24 can also be moved relative to the robotic dispenser 42, or both can move relative to each other. The robotic dispenser 42 for the second polymeric composition can be the same or different from the robotic dispenser 42 for the first polymeric composition.

[0066] The second polymeric composition can be applied in various amounts to form the inner tie-layer 36. Typically, the second polymeric composition is applied such that the inner tie-layer 36 has a thickness of from about 0.25 to about 1 .25 mm on average, or any range between these values.

[0067] If present during application of the second polymeric composition, the peripheral tie- layer 40 can retain the inner tie-layer 36. For example, as shown in FIGs. 5 and 7, the polymeric compositions can be applied simultaneously. Alternatively, one of the polymeric compositions can be applied before the other, such as shown in FIGs. 8 and 9. While the cover sheet 30 is shown in FIGs. 6-9, the substrate 24 may also have similar application steps, i.e., the cover sheet 30 can be swapped out for the substrate 24 in FIGs. 6-9. Various combinations of application of one or both of the polymeric compositions on one or both of the cover sheet 30 and the substrate 24 can be utilized to form the module 20.

[0068] After the second polymeric composition is applied to the cover sheet 30 to form the inner tie-layer 36, or a portion thereof, the PV cells 32 are disposed on the inner tie-layer 36. The inner tie-layer 36 can be allowed to level prior to disposing the PV cells 32 to prevent gaps, voids, or other issues. The PV cells 32 may be disposed separately or simultaneously.

[0069] The PV cells 32 may be disposed by various means, such as by hand or a robotic grip 46. The robotic grip 46 can use vacuum or other means to hold the PV cells 32. The robotic grip 46 can be operatively connected to a track and/or arm (not shown) for movement. The PV cells 32 can simply be placed on top of the inner tie-layer 36 or slightly pressed into the inner tie-layer 36. Pressing generally ensures that no gaps or voids are present between the inner tie-layer 36 and the PV cells 32.

[0070] The inner tie-layer 36, or a portion thereof, may be cured (to a final cure state or partially thereto) prior to or after the PV cells 32 are disposed. For example, the inner tie- layer 36 can be cured via oven prior to disposing the PV cells 32. Applying heat to the inner tie-layer 36 generally facilitates cure of the inner tie-layer 36 from an uncured state to a final cured state. The peripheral tie-layer 40 can also be cured prior to the PV cells 32 being disposed, in addition or alternate to, the inner tie-layer 36 being cured. The peripheral tie-layer 40 can be cured prior to, after, or at the same time as the inner-tie layer 36. In certain embodiments, additional amounts of the first and second polymeric compositions can be applied to fully encapsulate the PV cells 32, such as shown in FIG. 6.

[0071] The invention method may further comprise the step of applying a third polymeric composition to the front face 26 of the substrate 24 to further form the inner tie-layer 36. The third polymeric composition can be the same as the second polymeric composition, such as shown in FIG. 5. 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. As an example, in some of these embodiments, the portion of the inner tie-layer 36 disposed on the substrate 24 as shown in FIG. 5, would be swapped out with a different layer formed from the third polymeric composition. 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. The third polymeric composition can be applied as like described above with the first and second polymeric compositions. The third polymeric composition can be cured at various times. The third polymeric composition can be a silicone. The inner tie-layer 36 can be cured before or after application of the third polymeric composition, if employed.

[0072] The invention method may further comprise the step of applying a fourth polymeric composition over the PV cells 32 to further form the inner tie-layer 36. The fourth polymeric composition can be applied in addition or alternate to the third polymeric composition. The fourth polymeric composition can be the same as the first polymeric composition, the same as the second polymeric composition, or different from the first, second, and third polymeric compositions. The fourth polymeric composition can be different in various ways, such as providing a modulus that falls between that of the first and second polymeric compositions. The fourth polymeric composition can be applied as like described above with the first and second polymeric compositions. The fourth polymeric composition can be cured at various times. In certain embodiments, the fourth polymeric composition comprises a silicone oil. The fourth polymeric composition can be useful for ensuring no air bubbles get trapped between the PV cells 32 and the inner tie-layer 36. The inner tie-layer 36 can be cured before or after application of the fourth polymeric composition, if employed.

[0073] 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-layers 36, 40 to form the module 20. As shown in FIG. 5, the substrate 24 and cover sheet 30 can be pressed together to form the module 20. As also shown, the peripheral tie-layer 40 and the inner tie-layer 36 are sandwiched between the substrate 24 and the cover sheet 30 with the PV cell(s) 32 encapsulated by the inner tie-layer 36. The inner tie-layer 36 may also have portions formed from the third and/or fourth polymeric compositions as described above. One or both of the tie-layers 36, 40 can be cured. Typically, at least the peripheral tie-layer 40 is cured prior to pressing the module 20.

[0074] In certain embodiments, the inner tie-layer 36 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 inner tie-layer 36 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 inner tie-layer 36. While not required, these embodiments may be useful in instances where the module 20 is cured via a vacuum-press process. If the peripheral tie-layer 40 is already cured at this time, the air can still escape, such as around and/or through the substrate 24, e.g. a nonwoven FG layer. [0075] The silicone composition used to form the tie-layer 58 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.

[0076] 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.

[0077] 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.

[0078] In even further embodiments, the complex viscosity is from 1 ,125,000 to 1 ,975,000, from 1 ,150,000 to 1 ,950,000, from 1 ,175,000 to 1 ,925,000, from 1 ,200,000 to 1 ,900,000, from 1 ,225,000 to 1 ,875,000, from 1 ,250,000 to 1 ,850,000, from 1 ,275,000 to 1 ,825,000, from 1 ,300,000 to 1 ,800,000, from 1 ,325,000 to 1 ,775,000, from 1 ,350,000 to 1 ,750,000, rom 1 ,375,000 to 1 ,725,000, om 1 ,400,000 to 1 ,700,000, rom 1 ,425,000 to 1 ,675,000, rom 1 ,450,000 to 1 ,650,000, om 1 ,475,000 to 1 ,625,000, rom 1 ,500,000 to 1 ,600,000, rom 1 ,525,000 to 1 ,575,000, om 1 ,550,000 to 1 ,575,000, rom 2,125,000 to 2,975,000, rom 2,150,000 to 2,950,000, om 2,175,000 to 2,925,000, rom 2,200,000 to 2,900,000, rom 2,225,000 to 2,875,000, om 2,250,000 to 2,850,000, rom 2,275,000 to 2,825,000, rom 2,300,000 to 2,800,000, om 2,325,000 to 2,775,000, rom 2,350,000 to 2,750,000, rom 2,375,000 to 2,725,000, om 2,400,000 to 2,700,000, rom 2,425,000 to 2,675,000, rom 2,450,000 to 2,650,000, om 2,475,000 to 2,625,000, rom 2,500,000 to 2,600,000, rom 2,525,000 to 2,575,000, om 2,550,000 to 2,575,000, rom 3,125,000 to 3,975,000, rom 3,150,000 to 3,950,000, om 3,175,000 to 3,925,000, rom 3,200,000 to 3,900,000, rom 3,225,000 to 3,875,000, om 3,250,000 to 3,850,000, rom 3,275,000 to 3,825,000, rom 3,300,000 to 3,800,000, om 3,325,000 to 3,775,000, rom 3,350,000 to 3,750,000, rom 3,375,000 to 3,725,000, om 3,400,000 to 3,700,000, rom 3,425,000 to 3,675,000, rom 3,450,000 to 3,650,000, om 3,475,000 to 3,625,000, rom 3,500,000 to 3,600,000, rom 3,525,000 to 3,575,000, om 3,550,000 to 3,575,000, rom 4,125,000 to 4,975,000, rom 4,150,000 to 4,950,000, om 4,175,000 to 4,925,000, rom 4,200,000 to 4,900,000, rom 4,225,000 to 4,875,000, om 4,250,000 to 4,850,000, rom 4,275,000 to 4,825,000, rom 4,300,000 to 4,800,000, om 4,325,000 to 4,775,000, rom 4,350,000 to 4,750,000, rom 4,375,000 to 4,725,000, om 4,400,000 to 4,700,000, rom 4,425,000 to 4,675,000, rom 4,450,000 to 4,650,000, om 4,475,000 to 4,625,000, rom 4,500,000 to 4,600,000, rom 4,525,000 to 4,575,000, or from 4,550,000 to 4,575,000, cPs at 25°C measured as described above.

0079] 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 rom 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 he 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.

[0080] 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 inner tie-layer 36. 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.

[0081] 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.

[0082] 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.

[0083] 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 inner tie-layer 36. 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.

[0084] 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 inner tie-layer 36 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.

[0085] 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 the lowest and highest of these values.

[0086] In certain embodiments, the module 20 is formed with application of pressure. For example, pressure can be applied to the module 20 via a bladder press. Other apparatuses can also be used to apply pressure to form the module 20. Suitable pressures are of from about 7 to about 350, about 20 to about 200, or about 30 to about 140, kPa, or any range between the lowest and highest of 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.

[0087] As introduced above, peripheral tie-layer 40 can act as a spacer, which is useful during manufacture of the module 20. Specifically, upon retraction of pressure from the module 20, the peripheral tie-layer 40 compensates for rebound. Said another way, the peripheral tie-layer 40 helps to minimize the level of flexing of the substrate 24 and/or cover sheet 30 at the edges and corners of the module 20 during application and removal of pressure from the module 20. This is especially true when the substrate 24 and the cover sheet 30 are both formed from glass. The peripheral tie-layer 40 also provides a layer of material that substantially prevents the cohesive failure of the substrate 24 and/or cover sheet 30 from the inner tie-layer 36 by providing a compressible tie-layer at the interface which can move with the substrate 24 and/or cover sheet 30 when they relax from the pressure previously applied to the module 20, e.g. after lamination, or pressure potentially applied to the module 20 during use. The peripheral tie-layer 40 can also prevent the PV cells 32 and tabbing ribbons 34 from bottoming out, as described above. As such, the peripheral tie-layer 40 can also provide for a thinner inner tie-layer 36, especially between the substrate 24 and the PV cells 32.

[0088] 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 method of forming a photovoltaic (PV) cell module comprising a substrate having a front face and a rear face spaced from the front face, a cover sheet having a front face and a rear face spaced from the front face of the cover sheet, an inner tie-layer disposed between the substrate and the cover sheet for coupling the rear face of the cover sheet to the front face of the substrate with the inner tie-layer having a surrounding edge, at least one PV cell disposed within the inner tie-layer, and a peripheral tie-layer also disposed between the substrate and the cover sheet and peripherally disposed around the surrounding edge of the inner tie-layer for further 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 around a periphery of i) the front face of the substrate and/or ii) the rear face of the cover sheet to form the peripheral tie-layer on the face(s) in an uncured state;

optionally, curing the peripheral tie-layer to a cured state;

applying a second polymeric composition different than the first polymeric composition to ii) the rear face of the cover sheet to form the inner tie-layer in an uncured state;

optionally, curing the inner tie-layer to a cured state;

disposing the PV cell on the inner tie-layer formed from the application of the second polymeric composition; and

combining the substrate and the cover sheet to form the PV cell module such that the peripheral tie-layer and the inner tie-layer are sandwiched between the substrate and the cover sheet with the PV cell encapsulated by the inner tie-layer.

2. The method as set forth in claim 1 wherein:

a) a modulus of elasticity of the peripheral tie-layer is greater than a modulus of elasticity of the inner tie-layer;

b) a modulus of elasticity of the peripheral tie-layer is from about 15 to about 50 kilopascals (kPa) and a modulus of elasticity of the inner tie-layer is from about 0.5 to about 12.5 kPa;

c) a modulus of elasticity of the peripheral tie-layer is from about 50 to about 2000 kilopascals (kPa) and a modulus of elasticity of the inner tie-layer is from about 0.5 to about 12.5 kPa;

d) both a) and b);

e) both a) and c); or f) a modulus of elasticity of the peripheral tie-layer is from about 50 to about 2000 kilopascals (kPa) and a modulus of elasticity of the inner tie-layer is from about 50 to about 2000 kPa.

3. The method as set forth in claim 1 or 2, wherein the first polymeric composition is: a) applied around the periphery of ii) the rear face of the cover sheet to form the peripheral tie-layer; and/or

b) applied around the periphery of i) the front face of the substrate to form the peripheral tie-layer.

4. The method set forth in any one of the preceding claims, wherein:

a) the peripheral tie-layer is cured prior to applying the second polymeric composition;

b) the peripheral tie-layer is cured prior to combining the substrate and the cover sheet; and/or

c) the inner tie-layer is cured prior to disposing the PV cell.

5. The method as set forth in any one of the preceding claims, 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.

6. The method as set forth in any one of the preceding claims, 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 layer for facilitating cure of the tie-layer from the uncured state to the cured state.

7. The method as set forth in any one of the preceding claims, wherein the:

a) first polymeric composition is applied such that the peripheral tie-layer has a width of from about 2.5 to about 150 millimeters (mm) on average and a thickness of from about 0.25 to about 1 .25 mm on average; and/or

b) second polymeric composition is applied such that inner tie-layer has a thickness of from about 0.25 to about 1 .25 mm on average.

8. The method as set forth in any one of the preceding claims, wherein the:

a) cover sheet is formed from glass, and/or

b) substrate is formed from glass.

9. The method as set forth in any one of the preceding claims, wherein each of the first and second polymeric compositions are hydrosilylation-reaction curable silicone compositions.

10. The method as set forth in any one of the preceding claims, wherein the:

a) first 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 the diorganopolysiloxane, each based on 100 parts by weight of the first polymeric composition; and/or

b) second 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 the diorganopolysiloxane, and from about 25 to about 65 parts by weight of a non-reactive organopolysiloxane, each based on 100 parts by weight of the second polymeric composition.

1 1 . The module as set forth in any one of claims 1 -10, wherein the first 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.

12. The method as set forth in any one of claims 1 -1 1 , wherein the second 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.

13. A photovoltaic (PV) cell module comprising:

a substrate having a front face and a rear face spaced from said front face;

a cover sheet having a front face and a rear face spaced from said front face of said cover sheet;

an inner tie-layer disposed between said substrate and said cover sheet for coupling said rear face of said cover sheet to said front face of said substrate with said inner tie-layer having a surrounding edge;

at least one PV cell disposed within said inner tie-layer; and

a peripheral tie-layer also disposed between said substrate and said cover sheet and peripherally disposed around said surrounding edge of said inner tie-layer for further coupling said rear face of said cover sheet to said front face of said substrate;

wherein said peripheral tie-layer is formed from a first polymeric composition and said inner tie-layer is formed from a second polymeric composition different than said first polymeric composition; and

wherein a modulus of elasticity of said peripheral tie-layer is greater than a modulus of elasticity of said inner tie-layer.

14. The module as set forth in claim 13 wherein:

a) said peripheral tie-layer abuts said surrounding edge of said inner tie-layer; and/or

b) each of said first and second polymeric compositions are hydrosilylation- reaction curable silicone compositions.

15. The module as set forth in claim 13 or 14, wherein:

a) a modulus of elasticity of said peripheral tie-layer is greater than a modulus of elasticity of said inner tie-layer;

b) a modulus of elasticity of said peripheral tie-layer is from about 15 to about 50 kilopascals (kPa) and a modulus of elasticity of said inner tie-layer is from about 0.5 to about 12.5 kPa;

c) a modulus of elasticity of said peripheral tie-layer is from about 50 to about 2000 kilopascals (kPa) and a modulus of elasticity of said inner tie-layer is from about 0.5 to about 12.5 kPa;

d) both a) and b);

e) both a) and c); or

f) a modulus of elasticity of said peripheral tie-layer is from about 50 to about 2000 kilopascals (kPa) and a modulus of elasticity of said inner tie-layer is from about 50 to about 2000 kPa.