Development of high-efficiency solar cell modules and new application fields are significant for the further development of photovoltaics (PVs) and the creation of new clean energy infrastructure based on PV. Notably, the development of PV-powered vehicle applications is desirable and very important for this end.According to the NEDO's Interim Report "PV-Powered Vehicle Strategy Committee," a new broader PV markets with more than 10 GW and 50 GW in 2030 and 2040, respectively, are expected to be established when PV-powered vehicles are developed. Cumulative PV capacity for PV-powered vehicles will be 50 GW and 0.4 TW in 2030 and 2040, respectively. This paper presents impacts on efficiency and cost for PV-powered vehicles. According to our survey, the use of more than 30% of high-efficiency PV enables 30 km per day driving without external charging and the society that the majority of the family cars run by the sunlight and without supplying gas. Thus, we are developing high-efficiency and low-cost solar cells and modules for automobile applications. In this paper, our analytical results for the efficiency potential of various solar cells for choosing candidates of high-efficiency solar cell modules for automobile applications. This paper also presents our recent approaches: demonstration car (Toyota Prius PHV) by using Sharp's high-efficiency III-V triple-junction solar cell modules with an output power of 860 W, static low concentrator InGaP/GaAs/InGaAs triple-junction solar cell module with efficiency of 32.84%, and so forth.

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We have developed a small-volume, high-power-output inverter with a high output power density using SiC power devices. To fully utilize the advantages of SiC power devices, it is necessary to reduce the inductance of the power module. This is done by using a double-layer ceramic substrate, attaining a low inductance of 5 nH. A double pulse test was carried out up to 60 A under a DC voltage of 600 V. The low inductance greatly reduced the surge voltage and the oscillation at the switching transient. The SiC inverter unit with a volume of 250 cc was assembled using three power modules. The cooling performance of the inverter unit was evaluated at a loss equivalent to an output power of 10 kW, and it was found that the inverter unit can output 10 kW at a junction temperature (Tj) of about 200 ºC.

The development of photovoltaics (PV)-powered vehicles are expected to contribute to reduce CO 2 emission of vehicles and create a clean energy society. This paper presents the impact of high-efficiency solar cell modules on reduction in CO 2 emission, charging cost reduction for electric vehicles, and reducing storage capacity of PV-powered electric vehicles. In this paper, the effects of solar cell module efficiency upon driving distance of PV-powered vehicles are also shown. Especially, the potential of Si tandem solar cells for PV-powered vehicle applications is discussed. This paper presents that the III-V/Si 3-junction solar cell modules with an efficiency of more than 37% have the potential of longer driving distance of 30 km/day average and more than 50 km/day on a clear day compared to an average 16 km/day driving by vehicles powered by 20% efficiency Si solar cell modules.

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