Design of low‐concentration static III‐V/Si partial CPV module with 27.3% annual efficiency for car‐roof application

A low‐concentration static III‐V/Si partial concentrator photovoltaic (CPV) module for area‐limited car roofs was designed and experimentally demonstrated. The concentrator lens geometry was optimized for an incidence‐angle dependency of annual global irradiance on a car‐roof (horizontal‐flat) surface by considering arbitrary car orientations. The designed lens with a geometrical concentration ratio of 3.5× for III‐V triple‐junction (3‐junction) cells can collect 46.6% and 36.4% of the annual irradiation onto a III‐V 3‐juction and Si cells, respectively, which are located under the III‐V cell. The module design was validated by indoor and outdoor tests using a prototype submodule. The results show that the present module can potentially achieve up to 27.3% annual module efficiency, as projected from the actual daily submodule efficiency of 20.8% assuming state‐of‐the‐art record cell efficiency. Furthermore, the outdoor test on a real curved car roof demonstrated that the effect of the curved surface on the power generation performance is comparable with that of a conventional PV module.