Photovoltaic devices are often sensitive to moisture and must be packaged in such a way as to limit moisture ingress for 25 years or more. Typically, this is accomplished through the use of impermeable front and backsheets (e.g., glass sheets or metal foils). However, this will still allow moisture ingress between the sheets from the edges. Attempts to hermetically seal with a glass frit or similarly welded bonds at the edge have had problems with costs and mechanical strength. Because of this, low diffusivity polyisobutylene materials filled with desiccant are typically used. Although it is well known that these materials will substantially delay moisture ingress, correlating that to outdoor exposure has been difficult. Here, we use moisture ingress measurements at different temperatures and relative humidities to find fit parameters for a moisture ingress model for an edge-seal material. Then, using meteorological data, a finite element model is used to predict the moisture ingress profiles for hypothetical modules deployed in different climates and mounting conditions, assuming no change in properties of the edge-seal as a function of aging.

Drop-induced failures are most dominant in portahle electronic products. In this &dy; explicit fmite element models ,have been used to study the transient dynamics of printed circuit hoards during drop from 6ft. Methodologies for modeling components using smeared property formulations have been investigated. Reduced integration element formulations examined. includeshell and solid elements. . Model predictions have been validated with experimental data. Results show that models with smeared properties can predict transient-dynamic response of hoard assemblies in drop-impact, fairly accurately. High-speed data acquisition system has been used to capture in-situ strain, continuity and acceleration data in excess of 1 million samples per second. Ultra high-speed video at 40,000 fps per second has been used to capture the deformation kinematics. Component types examined includeplastic hall-grid arrays, tape-may BGA, QFN, and C2BGA. Model predictions have been correlated with experimental data.Impact of experimental error sources o n , model correlation with experiments also has been investigated 0-7803-83656/04/$20.00 WOO4 IEEE

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