Temperature accelerated life test on commercial concentrator III–V triple‐junction solar cells and reliability analysis as a function of the operating temperature

A temperature accelerated life test on commercial concentrator lattice-matched GaInP/GaInAs/Ge triple-junction solar cells has been carried out. The acceleration of the aging has been accomplished by subjecting the solar cells at temperatures markedly higher than the nominal working temperature inside a concentrator, and the nominal photo-current condition (820 X) has been emulated by injecting current in darkness. Three tests at different temperatures have been carried out. The failure distributions across the three test temperatures have been fitted to an Arrhenius-Weibull model. An Arrhenius activation energy of 1.59eV was determined from the fit. The reliability functions and parameters of these solar cells at two nominal working conditions (80and100 degrees C) have been obtained. In both cases, the instantaneous failure rate function monotonically increases, that is, the failures are of the wear-out kind. We have also observed that the reliability data are very sensitive to the nominal temperature condition. In fact, at a nominal working condition of 820 X and 80 degrees C, assuming that the concentration module works 5h per day, the warranty time obtained for a failure population of 5% has been 113years. However, for a nominal working condition of 820 X and 100 degrees C, the warranty time obtained for a failure population of 5% has been 7years. Therefore, in order to offer a long-term warranty, the working temperature could be a key factor in the design of the concentration photovoltaic systems. Copyright (c) 2014 John Wiley & Sons, Ltd.