LeTID - A Comparison of Test Methods on Module Level

Light and elevated Temperature Induced Degradation (LeTID) can lead to significant power losses within the first months or years of PV module operation. Comparably slow degradation rates and the superposition of degradation and regeneration processes challenge the design of time- and cost-efficient but reliable test procedures. We investigate performance changes of commercially available standard modules and mini-modules during LeTID tests at different test conditions, varying test temperature and injection level. When increasing temperature and injection level, we observe significant differences between the acceleration of degradation and regeneration processes as well as the amount of detected degradation for monocrystalline and multicrystalline PERC modules. This has to be taken into account when performing accelerated LeTID tests.