Current-soaking and dark storage effects of polycrystalline thin film solar modules

Polycrystalline thin film modules as CIS and CdTe are known to exhibit metastabilities and performance changes with light exposure or dark storage. In this report the behavior of CIS and CdTe modules from different manufactures is investigated in terms of dark storage after a prolonged outdoor exposure and short preconditioning with current-soaking (CS), An approach which could be used to preserve the metastable state- a condition closer to real operating conditions - of the modules during a period of storage in the dark. We observed power losses up to -2% in the first hour and up to -11% after 10 days of dark storage. By using current-soaking changes in power could be recovered for most of the tested modules.