WO2016022611A1

WO2016022611A1 - Impact-resistant photovoltaic modules

Info

Publication number: WO2016022611A1
Application number: PCT/US2015/043689
Authority: WO
Inventors: Mehrdad M. MOSLECHI
Original assignee: Solexel, Inc.
Priority date: 2014-08-04
Filing date: 2015-08-04
Publication date: 2016-02-11

Abstract

A photovoltaic module comprises a frontside photovoltaic module stack having a frontside cover, a styrene butadiene block copolymer sheet, and an encapsulant layer and a backside photovoltaic module stack. The frontside photovoltaic module stack and the backside photovoltaic module stack encapsulating a solar cell.

Description

IMPACT-RESISTANT PHOTOVOLTAIC MODULES

CROSS-REFERENCE TO RELATED APPLICATIONS

[001] This application claims the benefit of U.S. provisional patent application

62/033,091 filed on Aug. 4, 2014, which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

[002] The present disclosure relates in general to the fields of solar photovoltaics (PV), and more particularly to solar photovoltaic module structures and fabrication methods.

BACKGROUND

[003] The effects from weather and wear in field use to photovoltaic cells and modules, or solar cells and modules, due to, for example, mechanical impacts from hail, falling tree branches, and in some instances walking on modules may lead to costly damage such as cracking and electrical power loss. Additionally, solar module materials in the field are subject to prolonged UV irradiance and often extreme temperatures and temperature swings. Weather and wear in the field are not limited to but may be particularly harmful to the solar cell frontside where much of the weather and mechanical impact occurs but which requires module frontside stack transparency to receive light. To protect solar cells without reducing power, current photovoltaic modules often rely on materials such as glass or often expensive thick, heavy, and/or rigid materials which may provide sufficient impact protection but also may limit certain solar cell application, for example to areas capable of withstanding and supporting heavier solar module structures.

Additionally, these module materials may be temperature sensitive such that their effectiveness and impact strength is reduced outside of a certain temperature range. Importantly, numerous considerations must be accounted for and balanced to provide solar module material improvement and innovation. BRIEF SUMMARY OF THE INVENTION

[004] Therefore, a need has arisen for lighter weight photovoltaic module with improved impact resistance. In accordance with the disclosed subject matter,

photovoltaic modules are provided which may substantially eliminate or reduces disadvantage and deficiencies associated with previously developed photovoltaic modules.

[005] According to one aspect of the disclosed subject matter, an impact resistant photovoltaic module is provided. A photovoltaic module comprises a frontside photovoltaic module stack having at least a frontside cover, a styrene butadiene block copolymer sheet, and an encapsulant layer and a backside photovoltaic module stack. The frontside photovoltaic module stack and the backside photovoltaic module stack encapsulating a solar cell.

[006] These and other aspects of the disclosed subject matter, as well as additional novel features, will be apparent from the description provided herein. The intent of this summary is not to be a comprehensive description of the claimed subject matter, but rather to provide a short overview of some of the subject matter's functionality. Other systems, methods, features and advantages here provided will become apparent to one with skill in the art upon examination of the following FIGURES and detailed description. It is intended that all such additional systems, methods, features and advantages that are included within this description, be within the scope of any claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[007] The features, natures, and advantages of the disclosed subject matter may become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference numerals indicate like features and wherein:

[008] Figs. 1 through 8 are cross-sectional diagram of photovoltaic module structures having an embedded frontside transparent impact-resistant layer comprising a styrene butadiene block copolymer sheet. DETAILED DESCRIPTION

[009] The following description is not to be taken in a limiting sense, but is made for the purpose of describing the general principles of the present disclosure. The scope of the present disclosure should be determined with reference to the claims. Exemplary embodiments of the present disclosure are illustrated in the drawings, like aspects and identifiers being used to refer to like and corresponding parts of the various drawings.

[010] And although the present disclosure is described with reference to specific embodiments, components, and materials, such as module encapsulants (transparent or otherwise), backside backsheets, and frontside cover sheets, one skilled in the art could apply the principles discussed herein to other solar module structures, fabrication processes, as well as alternative technical areas and/or embodiments without undue experimentation.

[011] Improved impact resistant, lighter weight, and semi-flexible solar photovoltaic module structures and fabrication methods are provided. These module stacks provide frontside impact strengthening and dispersion damping solutions on the module frontside, and optionally on the solar module backside as well, without performance or power loss and which may be integrated in a module packaging stack with proven inexpensive and reliable materials.

[012] The solutions provided: retain primary proven module packaging materials in the module stack (e.g., frontside flexible transparent fluoropolymer, polyolefin encapsulant, back sheet); result in negligible or no module performance reduction (excellent transparency); superior resistance to UV irradiance for performance reliability; thermal stability in the range of -40°C and +85 °C and capable of processing up to 160°C; are lightweight (e.g., in some instances lighter weight by greater than three times the standard c-Si module); add minimal incremental cost; are compatible with both building integrated photovoltaics BIPV (e.g., BIPV blinds) and non-BIPV module structures (e.g., indoor product applications); and may readily provide over twenty five years of field use reliability. [013] The disclosed solutions provide a thin (e.g., less than 1 mm) impact-strengthening sheet within a frontside module laminate stack, for example inserted or sandwiched within or between encapsulant layers, having a combination of impact dispersion and impact damping for impact resistance while retaining superior optical transparency required as part of the module frontside. The impact-strengthening sheet solution protections provided are sufficiently effective to substantially suppress or mitigate cell crack and power loss upon mechanical impact or in some instances humans walking on modules. The impact- strengthening sheet provides superior optical transparency in the wavelength range of interest (e.g., 400 nm - 1200 nm). The impact-strengthening sheet is stable for continuous operation in the temperature range of -40°C to +85°C and thermally stable during module lamination processes (e.g., for example lamination process temperatures applied for 30 min.). The impact-strengthening sheet is compatible with proven module front cover and back sheet materials and adheres well to module encapsulant layers such as polyolefm. Additionally, the impact-strengthening sheet is relatively inexpensive (e.g., the material plus process cost is less than or equal to $3/m² of the module) and based on abundant inexpensive base materials.

[014] The solar cell is embedded in a module stack (e.g., a module laminate stack) and protected from mechanical impact by a frontside module stack impact-strengthening styrene butadiene block copolymer sheet providing impact dispersion and damping. Optionally, a backside impact-strengthening styrene butadiene block copolymer sheet may also be used in the module stack (e.g., laminate stack).

[015] Styrene butadiene block copolymer (SBC) is a thermoplastic resin that is both transparent and impact-resistant. There are three primary types of SBCs including:

a. Poly(styrene-butadiene-styrene) (SBS)

b. Poly(styrene-isoprene-styrene) (SIS)

c. Poly(styrene-ethylene/butylene-styrene) (SEBS)

[016] The impact-dispersion and damping layer solutions herein comprise a material composed of styrene-butadiene block copolymer (SBC) having styrene repeating units and butadiene repeating units. SBC is made of alternating styrene and butadiene blocks. The styrene blocks provide material rigidity and a high degree of compatibility with other styrenic resins while the butadiene blocks provide high impact strength properties. The polybutadiene-phase (i.e., the rubber-phase) dispersion is on a finer scale than visible light wavelength, thus effectively providing enhanced impact strength, flexural properties, and other copolymer characteristics, without degrading optical transparency. SBC offers a combination of excellent impact strength and resistance, flexural (bend) strength, and high optical transparency.

[017] Importantly, styrenic block copolymers (SBCs) are the highest-volume thermoplastic elastomers (TPE) with annual consumption of about 1,200,000 metric tons. SBC applications include paving and roofing, footwear, sealants, adhesives, coatings, and advanced materials. In 2013, paving and roofing accounted for 36.1% of SBC market volume (followed by footwear which accounted for 24.6% of SBC market).

Additionally, SBC is used to provide a high optical appearance and is extensively utilized in many applications including food and display packaging. Other applications include: strong, transparent containers and packaging materials; transparent, impact-resistant parts for appliances/equipment; transparent cases and parts requiring hinge, flexural, and push- lock properties, such as eyeglasses and goggle cases. Blended SBC compositions are also suitable for molding, extruding, and forming.

[018] Thus, a wide range of commercially products are available with a proper balance between stiffness and flexibility and at a commercially competitive material cost suitable for photovoltaic application. Additionally, thin sheets of SBC (e.g., less than 1 mm) may be fabricated as SBC is suitable for molding, extruding, and forming processes.

[019] Exemplary commercially available material embodiments herein are provided herein for descriptive purposes. SBCs of alternating styrene butadiene polymer blocks, such as ASAFLEX™ by Asahi Kasei Chemicals Corp and particularly ASAFLEX™ 835, may provide total light transmission through 2-mm thick plate: -90% (with substantially higher transmission for 200-μιη thick layer). Blended SBC material compositions may be particularly advantageous. SBC sheets with excellent impact strength (both at room temperature of approximately +25 °C and at low temperatures of - 40°C) and high optical transparency may be made by using a blended mixture of -50% - 70% (wt.) SBC (e.g., ASAFLEX™) and -50% - 30% (wt.) of a styrenic copolymer, such as SC™ Polymer by PS Japan Corp. (or, for example, alternatively GPPS™ by PS Japan Corp.). Additionally, a styrenic thermoplastic elastomer, such as TUFPRENE™ a styrene -butadiene thermoplastic elastomer (SBS) by Asahi Kasei Chemicals Corp. and particularly TUFPRENE™ 125, may increase the sheet impact strength, while providing suitable optical transparency, of SBCs of alternating styrene butadiene polymer blocks and blends with SBCs of alternating styrene butadiene polymer blocks including SBCs of alternating styrene butadiene polymer blocks and styrenic copolymer blends.

[020] Thus, a superior inexpensive option to achieve the combination of high impact strength (extending to low temperatures) and high optical transparency is to use a three- part blend in the module frontside laminate comprising an SBC of alternating styrene butadiene polymer blocks/a styrenic copolymer/and a styrenic thermoplastic elastomer (e.g., a blend of ASAFLEX™ / SC™ / TUFPRENE™ and more particularly a blend of ASAFLEX™ 835 / SC™ / TUFPRENE™ 125). With reference to the blend above, blend composition considerations included increased impact strength using an increased weight percentage SBC of alternating styrene butadiene polymer blocks. The addition of a styrenic thermoplastic elastomer to the blend of an SBC of alternating styrene butadiene polymer blocks and a styrenic copolymer may improve low temperature impact strength (e.g., impact strength at temperatures as low as -40°C). The low temperature impact strength and optical transparency of the blend may be adjusted by varying the blending ratios in a three part blend of a SBC of alternating styrene butadiene polymer blocks/a styrenic copolymer/and a styrenic thermoplastic elastomer. For example, in some instances an approximately 0.2mm to 0.6mm thick extruded sheet of a three way blend of 50% SBC of alternating styrene butadiene polymer blocks/45% styrenic copolymer/and 5% styrenic thermoplastic elastomer may be advantageous to provide total light transmission of 98.6% and dart impact strength of -10 to >20 J at -40°C to 23 °C.

Alternatively, an approximately 0.2mm to 0.6mm thick extruded sheet of a three way blend of 50% SBC of alternating styrene butadiene polymer blocks/40% styrenic copolymer/and 10% styrenic thermoplastic elastomer may be advantageous to provide total light transmission of 98.1% and excellent dart impact strength of ~ 11 to 19 J at - 40°C to 23 °C.

[021] The impact-resistant lightweight module structures and design options described provide good impact strength and optical transparency for module performance, at a low cost, while compatible with known module materials (encapsulant, etc.), without reliability degradation. These structures and designs provided are compatible with proven lightweight module packaging and lamination materials (standard polyolefm encapsulant, FEP front cover sheet, and backsheet materials). Additionally, the structures and designs provided may eliminate the need to for rigid module backside support and allow for use of flexible module backsheet materials, for example proven materials such as Tedlar® by DuPont™.

[022] Figs. 1 through 8 are cross-sectional diagrams of photovoltaic module structures and designs with a frontside styrene butadiene block copolymer SBC serving as an impact strength and resistance layer. The photovoltaic module structures and designs described in the cross-sectional diagrams of Figs. 1 through 8 have a frontside material stack, frontside stack 4, and a backside material stack, backside stack 6, which encapsulate solar cell 2 (e.g., laminated solar cells such as backplane laminated solar cells for example having a laminate thickness of approximately 9 μιη). Solar cell 2 may comprise an array of electrically connected solar cells (e.g., an array of solar cells such as a 60 cell module).

[023] Importantly, although described utilizing like materials for like structures herein (e.g., an encapsulant layer), frontside and backside material stack layers, as well as like layers used more than once on the same module side, may have different material considerations and thus utilize different materials, for example the module backside material stack may not be restricted by the optical transparency considerations of the frontside material stack - thus backside materials, such as encapsulants, may be semi- or non-transparent in combination with transparent frontside materials. Further, although a key aspect of the present application provides flexible and impact resistant modules, module materials may be flexible, semi-rigid, or rigid or any combination thereof including materials having differing on the same module side and/or on the module frontside as compared to the module backside.

[024] In some instances, the photovoltaic module structures and designs described in the cross-sectional diagrams of Figs. 1 through 8 may provide 60-cell module weight in the range of 4.0 kg to 5.7 kg (depending on the cell and module structure and design). These module weights are 3.5x to 5x lower than standard comparable 60-cell framed glass- covered modules and about 4x to 6x lighter weight as compared to double-glass- laminated modules.

[025] The photovoltaic module structures and designs described in the cross-sectional diagrams of Figs. 1 through 8 may have some or all of like module laminate materials following: styrene butadiene block copolymer SBC 8, for example a three-way blend impact resistant sheet of an SBC of alternating styrene butadiene polymer blocks/a styrenic copolymer/and a styrenic thermoplastic; transparent frontside cover 12, for example a transparent flexible fiuoropolymer (e.g., fiuorinated ethylene propylene FEP) frontside cover sheet or alternatively a transparent flexible ethylene tetrafiuoro ethylene ETFE frontside cover sheet; encapsulant sheet 10, for example a flexible polyolefm encapsulant sheet or alternatively a flexible ethylene-vinyl acetate EVA encapsulant; module backsheet 14, for example a polyethylene terephthalate PET module backsheet or alternatively a fiber-reinforced plastic module backsheet; and a strengthening sheet 16, for example a strengthening polyethylene terephthalate PET sheet or alternatively a strengthening transparent plastic sheet. Module material density levels may be approximately: FEP 2.15 g/cm³; SBC 1.01 g/cm³; polyolefm 0.87 g/cm³.

[026] Styrene butadiene block copolymer SBC 8 may be styrene butadiene block copolymer SBC sheet for example having a thickness in the range of approximately 0.2 to 0.6 mm, or styrene butadiene block copolymer SBC 8 may be a three way blend impact resistant sheet of an SBC of alternating styrene butadiene polymer blocks/a styrenic copolymer/and a styrenic thermoplastic elastomer for example having a thickness in the range of approximately 0.2 to 0.6 mm (e.g., 0.2 to 0.6 mm thick extruded ultra-transparent semi-flexible plate of a blend of SBC of alternating styrene butadiene polymer blocks/a styrenic copolymer/and a styrenic thermoplastic elastomer such as ASAFLEX™ / SC™ / TUFPRENE™ and more particularly a blend of 50%

ASAFLEX™ 835/45% SC™ /and 5% TUFPRENE™ 125). Transparent frontside cover 12 may be a transparent flexible frontside fiuoropolymer cover sheet (e.g., a 50 to 125 μιη thick fluorinated ethylene propylene FEP film). Encapsulant sheet 10 may be a flexible polyolefm encapsulant sheet encapsulant (e.g., an 18 millimeter or 478 μιη thick polyolefm sheet). Module backsheet 14 may be a polyethylene terephthalate PET sheet (e.g., a 295 μιη PET backsheet). Strengthening sheet 16 may be a polyethylene terephthalate PET (e.g., a 50 to 100 μηι thick flexible biaxially-oriented PET sheet, for example made of Mylar® by Dupont Tejjin Films).

[027] In specific embodiments consistent with the module structures shown, a 0.2 to 0.6 mm thick sheet made of the three-way blend 50% SBC of alternating styrene butadiene polymer blocks/45% styrenic copolymer/and 5% styrenic thermoplastic elastomer blend embedded in the frontside laminate. And in specific embodiments consistent with the module structures shown in Figs. 2, 3, 4, 6, 7, and 8, a 0.2 to 0.6 mm thick sheet made of the three-way blend 50% SBC of alternating styrene butadiene polymer blocks/45% styrenic copolymer/and 5% styrenic thermoplastic elastomer blend is embedded in the backside laminate.

[028] Thus, in a specific embodiment as described with reference to Fig. 1, styrene butadiene block copolymer SBC 8 is a 0.2 to 0.6 mm thick extruded ultra-transparent semi-flexible plate of a blend of 50% ASAFLEX™ 835/45% SC™ /and 5%

TUFPRENE™ 125, encapsulant sheet 10 is an 18 millimeter or 478 μιη thick polyolefm sheet, transparent frontside cover 12 is a 50 to 125 μιη thick fluorinated ethylene propylene FEP film, and module backsheet 14 is a 295 μιη PET backsheet. And in a specific embodiment as described with reference to Fig. 5, the materials above are utilized in addition to strengthening sheet 16 is a 50 to 100 μιη thick flexible biaxially- oriented PET sheet of Mylar® by Dupont Tejjin Films.

[029] Fig. 1 is a cross-sectional diagram of photovoltaic module structure having an embedded frontside transparent impact-resistant layer where the thin (e.g., having a thickness in the range of 0.2 - 0.6 mm) transparent three-part blended SBC-based material frontside impact-resistant layer, SBC 8, sandwiched between two encapsulant layers, encapsulant sheets 10, and embedded within the frontside of module laminate, frontside 4.

[030] Fig. 2 is a cross-sectional diagram of photovoltaic module structure consistent with the module structure of Fig. 1 with an embedded backside transparent impact- resistant layer where the thin (e.g., having a thickness in the range of 0.2 - 0.6 mm) transparent three-part blended SBC-based material backside impact-resistant layer, SBC 8, sandwiched between two encapsulant layers, encapsulant sheets 10, and embedded within the backside of module laminate, module backside 6. As there may be no need for sheet transparency on the backside, the blended SBC-based backside sheet material composition in module backside 6 may be adjusted for desired combination of impact strength, rigidity/flexibility, and flame suppression. Backside-embedded blended SBC- based thin sheets, as shown in Figs. 2, 3, 4, 6, 7, and 8, may be optimized without transparency considerations to provide photovoltaic module structures with enhanced impact strength and flame suppression.

[031] As shown in the module structures of Figs. 1 and 2, each three-way blended SBC- based impact-strengthening material sheet is inserted (in the frontside laminate in the case of the module of Fig. 1 and in both the frontside and backside laminates in the case of the module of Fig. 2) by sandwiching the sheet between two thin encapsulant (e.g., polyolefm) layers. This may provide a low-risk approach for integration of each sheet in the module laminate.

[032] Fig. 3 is a cross-sectional diagram of photovoltaic module structure having an embedded frontside transparent impact-resistant layer SBC 8 pre-laminated to transparent frontside cover 12 in module frontside 4 and a transparent three-part blended SBC-based material backside impact-resistant layer, SBC 8, sandwiched between two encapsulant layers, encapsulant sheets 10, embedded in module backside 6. The module structure of Fig. 3 is similar to the module structure of Fig. 2 except that instead of sandwiching the three-way blended SBC-based impact-strengthening material sheet between two encapsulant layers in the frontside stack, the sheet is pre-laminated to the transparent front-cover fluoropolymer (e.g., FEP) sheet followed by module lamination of the entire stack. This approach reduces the frontside encapsulant layers from two to one. The module structures of Figs. 2 and 3 may use identical the backside laminate structures.

[033] Fig. 4 is a cross-sectional diagram of photovoltaic module structure similar to the module structure of Fig. 3 with an embedded backside transparent impact-resistant layer SBC 8 pre-laminated to module backsheet 14 in module backside 6. The module structure of Fig. 4 is similar to the module structure of Fig. 2 except that instead of sandwiching the three-way blended SBC-based impact-strengthening material sheet between two encapsulant layers in the frontside stack, the sheet is pre-laminated to the transparent front-cover fluoropolymer (e.g., FEP) sheet followed by module lamination of the entire stack. This approach reduces the frontside encapsulant layers from two to one. Similarly, in the module structure of Fig. 4 instead of sandwiching the three-way blended SBC-based impact-strengthening material sheet between two encapsulant layers in the backside stack, the SBC sheet is pre-laminated to the protective backside sheet followed by module lamination of the entire module frontside and backside stack.

[034] The module structures of Figs. 5 through 8 are similar to the module structures of Figs. 1 through 4, respectively, with the insertion of a frontside thin flexible transparent biaxially-oriented PET film (e.g., a 50 to 100 μιη thick transparent PET film)— shown as strengthening sheet 16 in Figs. 5 through 8. The frontside thin flexible transparent biaxially-oriented PET film may be pre-laminated to the three-way blended impact resistant SBC sheet, for example with reference to Figs. 5 through 8 strengthening sheet 16 may be pre-laminated on SBC 8. In some instances, the module structures of Figs. 1 through 4 may be lower cost and also have higher maximum optical transparency (and thus higher module performance). In some instances, the module structures of Figs. 5 through 8 may further enhance the impact-strengthening property of the frontside SBC sheet (e.g., three-way blended SBC-based impact-strengthening material sheet) without a major loss of transparency.

[035] Fig. 5 is a cross-sectional diagram of photovoltaic module structure similar to the module structure of Fig. 1 with a strengthening sheet 16 on SBC 8 in the module frontside 4. The strengthening sheet or insert may be a transparent and shatterproof material to enhance the strength of an SBC sheet and that may also act as a water and gas barrier. Fig. 6 is a cross-sectional diagram of photovoltaic module structure similar to the module structure of Fig. 2 with a strengthening sheet 16 on SBC 8 in the module frontside 6. Fig. 7 is a cross-sectional diagram of photovoltaic module structure similar to the module structure of Fig. 3 with a strengthening sheet 16 on SBC 8 in the module frontside 4. Strengthening sheet 16 may be pre-laminated to SBC 8 and transparent frontside cover 12 in module frontside 4. Fig. 8 is a cross-sectional diagram of photovoltaic module structure similar to the module structure of Fig. 4 with a

strengthening sheet 16 on SBC 8 in the module frontside 4.

[036] The foregoing description of the exemplary embodiments is provided to enable any person skilled in the art to make or use the claimed subject matter. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the innovative faculty. Thus, the claimed subject matter is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMS What is claimed is:

1. A photovoltaic module, comprising:

a frontside photovoltaic module stack having at least a frontside cover, a styrene butadiene block copolymer sheet, and an encapsulant layer;

a solar cell; and

a backside photovoltaic module stack least an encapsulant and a backsheet, said frontside photovoltaic module stack and said backside photovoltaic stack encapsulate said solar cell.

2. The photovoltaic module of Claim 1, wherein said styrene butadiene block

copolymer sheet has a thickness in the range of 0.2 to 0.6 mm.

3. The photovoltaic module of Claim 1, wherein said styrene butadiene block

copolymer sheet is a three-way blend of styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/styrenic copolymer/and styrenic thermoplastic elastomer sheet.

4. The photovoltaic module of Claim 3, wherein said three-way blend of styrene butadiene block copolymer of alternating styrene butadiene polymer

blocks/styrenic copolymer/and styrenic thermoplastic elastomer sheet is 50% styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/45% styrenic copolymer/and 5% styrenic thermoplastic elastomer.

5. The photovoltaic module of Claim 3, wherein said three-way blend of styrene butadiene block copolymer of alternating styrene butadiene polymer

blocks/styrenic copolymer/and styrenic thermoplastic elastomer sheet is 50% styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/45% styrenic copolymer/and 5% styrenic thermoplastic elastomer and has a thickness in the range of 0.2 to 0.6 mm.

6. The photovoltaic module of Claim 1, further comprising a polyethylene terephthalate film pre-laminated to said styrene butadiene block copolymer sheet.

7. The photovoltaic module of Claim 1, wherein said backside photovoltaic module stack has at least a styrene butadiene block copolymer sheet.

8. The photovoltaic module of Claim 7, further comprising a polyethylene

terephthalate film pre-laminated to said frontside photovoltaic module styrene butadiene block copolymer sheet and a polyethylene terephthalate film pre- laminated to said backside photovoltaic module styrene butadiene block copolymer sheet.

9. The photovoltaic module of Claim 1, wherein said solar cell is an array of

electrically connected solar cells.

10. A photovoltaic module, comprising:

a frontside photovoltaic module stack having at least a three-way blend of styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/styrenic copolymer/and styrenic thermoplastic elastomer sheet laminated to a polyethylene terephthalate film;

a solar cell; and

a backside photovoltaic module stack having at least a three-way blend of styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/styrenic copolymer/and styrenic thermoplastic elastomer sheet laminated to a polyethylene terephthalate film,

said frontside photovoltaic module stack and said backside photovoltaic stack encapsulating said solar cell.

11. A photovoltaic module of Claim 10, wherein said frontside photovoltaic module stack three-way blend of styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/styrenic copolymer/and styrenic thermoplastic elastomer sheet is 50% styrene butadiene block copolymer of alternating styrene butadiene polymer blocks/45% styrenic copolymer/and 5% styrenic thermoplastic elastomer.

12. The photovoltaic module of Claim 10, wherein said solar cell is an array of

electrically connected solar cells.