Voltage dependence of potential-induced degradation and recovery on photovoltaic one-cell laminates

Abstract

A high voltage degradation mechanism on photovoltaic (PV) modules called potential-induced degradation (PID) has gained a lot of attention since 2010 when Solon published their findings about PID. The research conducted on PID mainly focused on industrial scale PV systems where potential differences between the solar cell and the grounded frame in the order of 1000 V and even more are not uncommon. In this work, a stress test for PID according to IEC 62804-1 and a recovery test in the same conditions on a set of five one-cell laminates is performed. However, by stressing the one-cell laminates at different voltages (-200 V, -600 V and -1000 V) and curing them at +600 V, which is compliant with resisential voltages in the PV market, and +1000 V as a reference, more insight in the reversibillity of PID is gained. This can lead to a voltage dependent model for PID, even at high degradation levels. Furthermore, the impact of PID at different stress voltages on the different operational parameters of the one-cell laminates and their physical meaning is described. At last, it is shown that the dependency of the stress voltage on PID as a funciton of time exhibits a complex behavior.