Analysis of temperature coefficients and their effect on efficiency of solar cell modules for photovoltaics-powered vehicles

Abstract

Development of vehicles that are powered by photovoltaics (PV) is desirable, and is crucial for reduction in CO2 emissions from the transport sector to realize a decarbonized society. Our investigations show that the majority of the passenger cars that cruise only with solar energy can be realized by installing a high-efficiency PV module. Although the Toyota Prius demonstration car, which is equipped with a 860 W rated-output power PV module, has shown a 36.6 km d−1 PV-powered driving range at solar irradiance of 6.2 kWh m−2 d−1, practical driving ranges of PV-powered vehicles are shown to be shorter than the estimated values due to some losses of solar cell modules, such as temperature rise under sunny conditions. In this paper, we conduct a systematic analysis of the effects of these losses on the PV-powered driving range in order to obtain guidelines for the development of highly efficient solar cell modules for vehicle integrated applications. The analytical results show that the III–V compound solar cell modules have more suitable properties compared to other cells because of their higher potential conversion efficiencies of 37% with a smaller temperature coefficient of −0.19% °C−1 compared to −0.29% °C−1 for Si back contact solar cell modules and −0.26% °C−1 for Si heterojunction solar cell modules. Our theoretical calculations that take these losses into account suggest that installing the III–V-based triple-junction solar cell modules provides a potential PV-powered driving range of 30 km d−1 on average, and more than 50 km d−1 on a sunny day under the irradiation conditions in Japan.