Application of Anand-Type Viscoplastic Solder Material Model for Thermal Stress Analysis/Life Prediction of Concentrating Photovoltaic (CPV) Module

Abstract

Aiming at understanding the structural integrity of a concentrating photovoltaic (CPV) module configuration, Finite Element (FE) thermal stress analysis is carried out in this investigation. Nonlinear viscoplastic analysis using the temperature profile of CPV cell fatigue test, is performed to evaluate the structure strength and subsequently predict the life of a CPV module. The result reveals that the maximum characteristic stresses of the PV cell components and heat sink are below the strength allowable for the corresponding materials under both the steady-state and over-night idle conditions. Critical locations on the solder that are potentially susceptible to structural failure after a few thousand thermal cycles due to excessive shear stress are identified. A rough estimation of the module life is provided and compared with the fatigue test. This investigation provides firsthand understanding of the structural integrity of CPV modules and is thus beneficial for the solar energy community.

Relative lifetime prediction for CPV die-attach layers

“…Cyclic changes in the temperature of the assembly result in differential thermal expansion, subjecting the assembly to thermomechanical fatigue. Cracking of the die-attach material due to thermomechanical fatigue has been suggested as a key failure mechanism for some CPV systems [1], [2].…”