Correlation of Leakage Current Pathways and Potential Induced Degradation of CIGS Thin Film Solar Modules

摘要

The life time of over 20 years is a unique feature of PV modules. Because of weather exposition and the system design of PV power plants system induced degradation can occur. In case of CIGS PV modules it is called Potential Induced Degradation (PID). The rate of degradation depends on the transferred charge, which can be determined by measuring the leakage currents because of the potential between module connectors and ground. Thereby only the sum of the leakage current can be measured, but there are different leakage current pathways. The main pathways are through the cover glass and the back glass/ material. For a real lifetime prediction the correlation of climate chamber tests and outdoor conditions is necessary. A method for measuring the exclusive leakage current pathway through the cover or the back glass was developed. The encapsulation foil enables the possibility to deactivate the leakage current pathways which is more harmful in relation to PID of CIGS PV modules.