Solar panel including a low moisture vapor transmission rate adhesive composition

Abstract

A solar panel including a front panel; a photovoltaic material layer deposited either directly on the front panel or directly on an anti-reflective coating formed between the front panel and the photovoltaic material layer; a backing panel; and an adhesive layer disposed between and adhering together the photovoltaic material layer and the backing panel, in which the adhesive layer comprises an adhesive composition, the adhesive composition comprising a low MVTR polymer or copolymer and a silane-modified polymer or copolymer. In another embodiment, the solar panel includes module wire openings which are filled by an adhesive composition comprising a low MVTR polymer or copolymer and a silane-modified polymer or copolymer. A method of making the solar panel is provided.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] The present application is a continuation of and claims priority under 35 U.S.C. §120 to copending, commonly owned U.S. application Ser. No. 10 / 224,983, filed 21 Aug. 2002, the entirety of which is hereby incorporated herein by reference.FIELD OF THE INVENTION [0002] This invention relates to a solar panel including an adhesive layer including an adhesive composition which has a low moisture vapor transmission rate. The invention also relates to the fabrication of solar panels using such compositions for adhesive and for sealing around module wires and other structural elements of solar panels. BACKGROUND OF THE INVENTION [0003] Photovoltaic solar panels, also referred to simply as solar panels, are generally of two basic designs. One design employs crystalline silicon wafers connected together and embedded in a laminating film. The laminating film and the wafers embedded therein are typically sandwiched between two lights, or panels, of...

AI Technical Summary

Benefits of technology

[0015] The adhesive composition of the present invention provides an advantage in that, in addition to having a low MVTR, due to the presence of excess silane groups on the silane-modified polymer or copolymer, any moisture which may find its way into the adhesive composition merely results in further cross-linking of the silane-modified polymer or copolymer, rather than resulting in any break-down or deterioration of the adhesive composition or other components of the solar panel. Thus, in addition to providing enhanced strength and substrate adhesion to the adhesive composition, the silane-modified polymer or copolymer provides extended protection from any moisture which may penetrate into the adhesive composition.

Problems solved by technology

Solar panels are deleteriously affected primarily by moisture which may permeate into the panel, reaching the electrical connections or the photovoltaic materials.

Water penetration into solar panels has been a long-standing problem.

Solar panels may also be deleteriously affected by wind and sunlight, which may result in failure of the adhesive layer.

Wind causes obvious physical damage, and sunlight results in heating of the solar panel and exposure to ultraviolet (UV) radiation.

Operating temperatures of solar panels have been measured as high as 110° C. Thermoplastic adhesives soften at elevated temperatures and are susceptible to UV-induced breakdown.

Many thermosetting materials suffer from unacceptably high MVTR.

Crosslinked EVA provides high strength, but suffers from a relatively high MVTR.

Module wire sealing materials suffer from the same problems as do the assembly adhesives.

The hot melt butyl systems suffer from the inability to achieve high strength since they are generally supplied as a thermoplastic material and they lose strength as temperatures increase, as noted above.

The problems of excluding moisture from solar panels, and of finding adhesives with suitably low MVTR properties, in addition to the other properties required of such adhesives, have been long standing.

However, none has satisfactorily provided both the required strength and related properties, and the required low MVTR properties.

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