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A solar cell module comprises a solar cell layer and an ionomer sheet. The ionomer sheet comprises a first ionomer that is the neutralized product of a first precursor acid copolymer, which, in turn, comprises copolymerized units of ethylene and about 20 to about 30 wt % of copolymerized acrylic or

A solar cell module comprises a solar cell layer and an ionomer sheet. The ionomer sheet comprises a first ionomer that is the neutralized product of a first precursor acid copolymer, which, in turn, comprises copolymerized units of ethylene and about 20 to about 30 wt % of copolymerized acrylic or methacrylic acid. The first precursor acid copolymer has a melt flow rate of about 70 to about 1000 g/10 min. When neutralized to a level of about 40% to about 90% and when comprising counterions that consist essentially of sodium cations, the first precursor acid copolymer produces a sodium ionomer that has a melt flow rate of about 0.7 to about 25 g/10 min and a freeze enthalpy that is not detectable or that is less than about 3.0 j/g. The ionomer sheet may further comprise a second ionomer that is different from the first ionomer.

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1. A solar cell module comprising a solar cell layer and an ionomer sheet, wherein: (A) the solar cell layer comprises a single solar cell or a plurality of electrically interconnected solar cells; and(B) the ionomer sheet comprises an ionomer composition, said ionomer composition comprises a first

1. A solar cell module comprising a solar cell layer and an ionomer sheet, wherein: (A) the solar cell layer comprises a single solar cell or a plurality of electrically interconnected solar cells; and(B) the ionomer sheet comprises an ionomer composition, said ionomer composition comprises a first ionomer that is the neutralized product of a first precursor acid copolymer, wherein (i) the first precursor acid copolymer comprises copolymerized units of ethylene and about 20 to about 30 wt %, based on the total weight of the first precursor acid copolymer, of copolymerized units of a first α,β-ethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid; (ii) the first precursor acid copolymer has a melt flow rate of about 70 to about 1000 g/10 min, as determined in accordance with ASTM D1238 at 190° C. and 2.16 kg; wherein (iii) the first precursor acid copolymer, being neutralized to a level of about 40% to about 90% based on the total number of the carboxylic acid groups present in the first precursor acid copolymer, produces a sodium ionomer, said sodium ionomer comprising carboxylate groups and counterions, and said counterions consisting essentially of sodium cations, and wherein (iv) the sodium ionomer has a melt flow rate of about 0.7 to about 25 g/10 min and a freeze enthalpy that is not detectable or that is less than about 3.0 j/g, as determined by differential scanning calorimetry (DSC) in accordance with ASTM D3418. 2. The solar cell module of claim 1, wherein the first precursor acid copolymer has a melt flow rate of about 100 to about 500 g/10 min. 3. The solar cell module of claim 1, wherein the first precursor acid copolymer comprises about 20 to about 25 wt % of copolymerized units of the first α,β-ethylenically unsaturated carboxylic acid. 4. The solar cell module of claim 1, wherein about 40% to about 70% of the carboxylic acid groups present in the first precursor acid copolymer have been neutralized by a sodium ion-containing base. 5. The solar cell module of claim 1, wherein about 10% to about 60% of of the carboxylic acid groups present in the first precursor acid copolymer has been neutralized by a zinc ion-containing base. 6. The solar cell module of claim 4, wherein the first ionomer has a melt flow rate of about 1 to about 10 g/10 min. 7. The solar cell module of claim 4, wherein the first ionomer has a freeze enthalpy of less than 2 j/g. 8. The solar cell module of claim 1, wherein the ionomer composition further comprises a second ionomer that is the neutralization product of a second precursor acid copolymer, wherein, (i) the second precursor acid copolymer comprises copolymerized units of ethylene and about 18 to about 30 wt %, based on the total weight of the first precursor acid copolymer, of copolymerized units of a second α,β-ethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid; (ii) the second α, β-ethylenically unsaturated carboxylic acid is the same as or different from the first α,β-ethylenically unsaturated carboxylic acid; (iii) the second precursor acid copolymer has a melt flow rate of about 60 g/10 min or less; and (iv) the second ionomer has a melt flow rate of about 10 g/10 min or less, as determined in accordance with ASTM D1238 at 190° C. and 2.16 kg. 9. The solar cell module of claim 8, wherein the first precursor acid copolymer has a melt flow rate of about 150 to about 400 g/10 min and the second precursor acid copolymer has a melt flow rate of about 30 g/10 min or less. 10. The solar cell module of claim 8, wherein the first precursor acid copolymer comprises about 20 to about 25 wt % of copolymerized units of the first α,β-ethylenically unsaturated carboxylic acid, and, independently, the second precursor acid copolymer comprises about 20 to about 25 wt % of copolymerized units of the second α,β-ethylenically unsaturated carboxylic acid. 11. The solar cell module of claim 8, wherein the first ionomer and the second ionomer have been neutralized by a sodium ion-containing base. 12. The solar cell module of claim 8, wherein the first ionomer has a melt flow rate of about 0.7 to about 10 g/10 min and the second ionomer has a melt flow rate of about 5 g/10 min or less. 13. The solar cell module of claim 8, wherein the ionomer composition comprises about 60 to about 95 wt % of the first ionomer and about 5 to about 40 wt % of the second ionomer, based on the total weight of the ionomer composition. 14. The solar cell module of claim 1, wherein the ionomer sheet is in the form of a monolayer sheet and consists essentially of the ionomer composition. 15. The solar cell module of claim 1, wherein the ionomer sheet is in the form of a multilayer sheet and comprises two or more sub-layers, and wherein at least one of the sub-layers consists essentially of the ionomer composition and each of the other sub-layer(s) comprises a polymer selected from the group consisting of acid copolymers, ionomers of acid copolymers, poly(ethylene vinyl acetates), poly(vinyl acetals), polyurethanes, polyvinylchlorides, polyethylenes, polyolefin block copolymer elastomers, copolymers of an α-olefin and an α,β-ethylenically unsaturated carboxylic acid ester, silicone elastomers, epoxy resins, and combinations of two or more thereof. 16. The solar cell module of claim 1, wherein the ionomer sheet has a total thickness of about 1 to about 120 mils (about 0.025 to about 3 mm). 17. The solar cell module of claim 1, wherein the ionomer sheet is directly laminated to the solar cell layer. 18. The solar cell module of claim 1, wherein the solar cell layer has a front sun-facing side and a back non-sun-facing side. 19. The solar cell module of claim 18, which comprises a front encapsulant layer laminated to the sun-facing side of the solar cell layer and a back encapsulant layer laminated to the non-sun-facing side of the solar cell layer, wherein one of the front and back encapsulant layers is the ionomer sheet and the other of the front and back encapsulant layers comprises a polymeric material selected from the group consisting of acid copolymers, ionomers of acid copolymers, poly(ethylene vinyl acetates), poly(vinyl copolymer acetals), polyurethanes, polyvinylchlorides, polyethylenes, polyolefin block elastomers, copolymers of an α-olefin and an α,β-ethylenically unsaturated carboxylic acid ester, silicone elastomers, epoxy resins, and combinations thereof. 20. The solar cell module of claim 19, which comprises two of the ionomer sheets, wherein each of the front and back encapsulant layers is one of the two ionomer sheets. 21. The solar cell module of claim 19, further comprising an incident layer, wherein the incident layer is an outermost surface layer of the module and is positioned on the sun-facing side of the solar cell layer, and wherein the incident layer is selected from the group consisting of (i) glass sheets, (ii) polymeric sheets comprising a polymer selected from the group consisting of polycarbonates, acrylics, polyacrylates, cyclic polyolefins, polystyrenes, polyamides, polyesters, fluoropolymers, and combinations of two or more thereof, and (iii) polymeric films comprising a polymer selected from the group consisting of polyesters, polycarbonate, polyolefins, norbornene polymers, polystyrene, styrene-acrylate copolymers, acrylonitrile-styrene copolymers, polysulfones, nylons, polyurethanes, acrylics, cellulose acetates, cellophane, poly(vinyl chlorides), fluoropolymers, and combinations of two or more thereof. 22. The solar cell module of claim 19, further comprising a backing layer, wherein the backing layer is an outermost surface layer of the module and is positioned on the non-light receiving side of the solar cell layer, and wherein the backing layer is selected from the group consisting of (i) glass sheets, (ii) polymeric sheets, (iii) polymeric films, (iv) metal sheets, and (v) ceramic plates, and wherein the polymeric sheets comprise a polymer selected from the group consisting of polycarbonates, acrylics, polyacrylates, cyclic polyolefins, polystyrenes, polyamides, polyesters, fluoropolymers, and combinations or two or more thereof; and the polymeric films comprise a polymer selected from the group consisting of polyesters, polycarbonates, polyolefins, norbornene polymers, polystyrenes, styrene-acrylate copolymers, acrylonitrile-styrene copolymers, polysulfones, nylons, polyurethanes, acrylics, cellulose acetates, cellophanes, poly(vinyl chlorides), fluoropolymers, and combinations of two or more thereof. 23. The solar cell module of claim 18, wherein the solar cells are wafer-based solar cells selected from the group consisting of crystalline silicon (c-Si) and multi-crystalline silicone (mc-Si) based solar cells. 24. The solar cell module of claim 23, which consists essentially of, in order of position, (i) an incident layer, (ii) a front encapsulant layer laminated to the sun-facing side of the solar cell layer, (iii) the solar cell layer, (iv) a back encapsulant layer laminated to the non-light receiving side of the solar cell layer, and (v) a backing layer, wherein one of the front encapsulant layer or the back encapsulant layer is the ionomer sheet. 25. The solar cell module of claim 18, wherein the solar cells are thin film solar cells selected from the group consisting of amorphous silicon (a-Si), microcrystalline silicon (μc-Si), cadmium telluride (CdTe), copper indium selenide (CIS), copper indium/gallium diselenide (CIGS), light absorbing dyes, and organic semiconductors based solar cells. 26. The solar cell module of claim 25, which consists essentially of, in order of position, (i) an incident layer, (ii) a front encapsulant layer comprising the ionomer sheet, and (iii) the solar cell layer, wherein the solar cell layer further comprises a substrate upon which the thin film solar cells are deposited and the substrate is positioned such that the substrate is an outermost surface of the module and is positioned on the non-sun-facing side of the solar cell layer. 27. The solar cell module of claim 25, which consists essentially of, in order of position, (i) the solar cell layer, (ii) a back encapsulant layer comprising the ionomer sheet, and (iii) a backing layer, wherein the solar cell layer further comprises a superstrate upon which the thin film solar cells are deposited and the superstrate is positioned such that the superstrate is an outermost surface of the module on the sun-facing side of the solar cell layer. 28. A process for preparing a solar cell module of claim 1, comprising: (i) providing an assembly comprising the solar cell layer and the ionomer sheet and (ii) laminating the assembly to form the solar cell module. 29. The process of claim 28, wherein the laminating step is conducted by subjecting the assembly to heat and optionally vacuum or pressure.