Nonuniformity of Irradiation Distribution on Vehicles' Bodies

Nonuniformity of irradiation in photovoltaic (PV) modules causes a current mismatch in the cells, which leads to energy losses. In the context of vehicle-integrated PV (VIPV), the nonuniformity is typically studied for the self-shading effect caused by the curvature of modules. This study uncovers the impact of topography on the distribution of sunlight on vehicle surfaces, focusing on two distinct scenarios: the flat-surface cargo area of a small delivery truck and the entire body of a commercial passenger vehicle. We employ a commuter pattern driving profile in Germany and a broader analysis incorporating random sampling of various road types and locations across 17,000 km² in Europe and 59,000 km² in the United States using LIDAR-derived topography and OpenStreetMap data. Our findings quantify irradiation inhomogeneity patterns shaped by the geographic landscape, road configurations, urban planning, and vegetation. The research identifies topography as the primary factor affecting irradiation distribution uniformity, with the vehicle's surface orientation and curvature serving as secondary influencers. The most significant variation occurs on vertical surfaces of the vehicle in residential areas, with the lower parts receiving up to 35% less irradiation than the top part of the car. These insights may be used to improve the design and efficiency of vehicle-integrated photovoltaic systems, optimizing energy capture in diverse environmental conditions.