Modeling Thermal Fatigue in CPV Cell Assemblies

@font-face {font-family: "Arial";}p.MsoNormal, li.MsoNormal, div. MsoNormal {margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: "Times New Roman";}div. Section1 {page: Section1;} A finite element model has been created to quantify the thermal fatigue damage of the CPV die attach. Simulations are used to compare to results of empirical thermal fatigue equations originally developed for accelerated chamber cycling. While the empirical equations show promise when extrapolated to the lower temperature cycles characterisitic of weather-induced temperature changes in the CPV die attach, it is demonstrated that their damage does not accumulate linearly: the damage a particular cycle contributes depends on the preceding cycles. Simulations of modeled CPV cell temperature histories provided for direct comparison of the FEM and empirical methods, and for calculation of equivalent times provided by standard accelerated test sequences.