Hot-Spot Endurance Test - Modifications for Bifacial Photovoltaic Modules

This paper aims at identifying suitable procedures for hot-spot endurance tests on bifacial PV modules. Drawing on the relevant background, i.e., normative requirements and available studies, it considers existing theoretical models and procedures for their application on bifacial modules. The resulting assumptions are subjected to experimental tests on four modules and in three approaches varying in their irradiance of module sides as well as location and degree of cell shading. In a second cycle, the first two approaches were repeated with extreme variations in irradiance level foreseen by the standard IEC 61215-2:2016. As it turns out, worst-case hot-spot temperatures appear in all three approaches, indicating a necessity for comprehensive testing. However, worst-case hot-spot temperatures are highly sensitive to irradiance intensity in general to an extent that may affect their passing or failing a hot-spot test, even if the test is done within the specified range of 900 to1100 W/m². It is therefore advised to reconsider the currently permitted leeway in equipment precision for both bifacial and conventional monofacial modules.