Influence Of Light Irradiation On Potential-Induced Degradation For Thin-Film Si Photovoltaic Modules

Delamination observed for superstrate-type thin-film Si photovoltaic (PV) modules exposed outdoors was reproduced by indoor acceleration test with high-voltage application. Such delamination was observed for the PV modules left in the air after potential-induced degradation (PID) acceleration test and was a kind of PID. The delamination occurred near the interface between glass and transparent conductive oxide. In this study the origins of the delamination for thin-film Si PV modules were analyzed and the influences of light irradiation and humidity were also investigated. The delamination occurred only at the position with voltage application and high concentration of Na was detected at the delamination region. Delamination was also enhanced by high humidity. It also turned out that light irradiation delays both deterioration of PV performances and also the delamination by high-voltage application. However, PID behaviors are almost the same regardless of including UV component. This is much different from crystalline Si case that UV component is required for the PID delay.