Gregory S. O'brien

Model development of degradation of PV modules backsheet with locating place of module

Performance of a photovoltaic (PV) module is related to the micro-environment around the module. The position of photovoltaic modules in an array row have a large effect on the yellowing and gloss of PV module backsheet exposed in Dfa climatic zone (Gaithersburg, MD) with a polyethylene naphthalate (PEN) outer layer. <Stress/ Response< models of yellowing and gloss-losing as function of location parameters of module, including the shed, row, measurement position in a same module and the distance of module location to the row center, are under development. The module installation height had the greatest influence on degradation of PEN PV backsheet in the Dfa climatic zone. The module backsheets at the end of an array have higher degradation rate (edge effect). The edge effect decreases with increasing of module installation heights.

Chapter 6:Commercial Synthesis and Applications of Poly(Vinylidene Fluoride)

Poly(vinylidene fluoride) (PVDF) was first introduced commercially in the 1960s for architectural coatings, followed shortly thereafter by additional grades for industrial applications with continued technology developments to service demand in other application areas. PVDF homopolymers and copolymers are synthesized commercially as stable aqueous latexes, or using suspension processes in which larger particle sizes are produced. Nearly all grades are melt and solution processable and are relatively low-cost fluoropolymers with excellent weatherability and resistance to chemical attack. They find application where excellent physical properties, coupled with ease of processability, are of critical importance. They are particularly useful in formulations for highly weatherable coatings, or processed for high-purity piping, porous membranes, binders for lithium ion batteries and photovoltaics, among others. PVDF, by volume, is the second-highest produced fluoropolymer worldwide, with the majority of demand from the USA, Europe, China and Japan. It continues to experience good market growth, and is projected to exceed a 5% volume increase per year for the foreseeable future.

Durability of photovoltaic backsheet outer weatherable layers

Photovoltaic backsheets are an essential part of photovoltaic modules. It is imperative that the backsheet perform and be shown to be weatherable over the 25 year expected module lifetime. This paper reports on findings from a study focused on understanding the durability of the outer weatherable layers of commercial backsheets exposed in south Florida. Within one year of exposure, Non-Fluoropolymer outer weatherable layers were found to be degrading, with cracking and erosion of the polymer matrix occurring. In contrast, after four years of exposure there is no evidence of degradation in backsheets protected with a Kynar® PVDF fluoropolymer layer.