Exploring suitable damp heat and potential induced degradation test procedures for Cu(In,Ga)(S,Se) photovoltaic modules

To ensure a longer lifetime for photovoltaic (PV) modules, many accelerated test standards are being developed or revised. Among the test standards, damp heat (DH) testing in the dark is widely employed to test the module durability. However, in the field, high temperature is usually accompanied by light irradiation. This difference can result in a degradation not observed in the field, especially in the case of Cu(In,Ga)(S,Se) (CIGS) PV modules. To explore suitable test procedures that simulate performance in the field appropriately, we investigated the effects of light irradiation and forward biasing, during DH testing and potential induced degradation (PID) testing of CIGS PV modules. In the case of the CIGS product we have tested, both light irradiation and forward biasing have suppressed degradation in DH as well as PID tests, and no degradation was found after light soaking. These results suggest the needs to add corresponding option(s) to the relevant test standards.