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 CO 2 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.

Analysis of Climate Conditions upon Driving Distance of Vehicle Integrated Photovoltaics‐Powered Vehicles

“…Table 2 suggests additional power loss of 13% and 12% for the Toyota Prius and Nissan Van demonstration cars. Because there are additional losses such as temperature rise of VIPV modules [ 11 ] and partial shading, [ 8,23,24 ] as shown in Table 2, further analysis is necessary.…”

“…The following power losses of VIPV‐powered vehicles and VIPV modules have been reported in some papers: fluctuations in solar irradiance, [ 6,10 ] fluctuation of the solar spectrum, [ 10 ] frequent variation in the orientation angle of the VIPV during driving, [ 10 ] the curved surface, [ 8,10 ] temperature variations, [ 11 ] and shadow loss and partial shading. [ 8,12,13 ]…”

Impact and recent approaches of high-efficiency solar cell modules for PV-powered vehicles

“…1) Regarding the module temperature of VIPV, the necessity of preventing a temperature rise of VIPV modules and the effectiveness of developing high-performance solar cell modules with good temperature coefficient (TC) is shown in our previous paper. 18) Figure 10 shows calculated values for changes in driving range as a function of temperature rise and TC under the assumption of the VIPV module efficiency of 30%. In the calculation by using Eq.…”

“…We used the following values; SI is 4 kWh m −2 d −1 , and η s is 81.2% which is not contained the module temperature correction. 18) The practical driving distance was calibrated by using 4 kWh m −2 d −1 . Figure 2 shows calculated results for changes in DD of PV-powered vehicles as a function of VIPV peak output power in comparison with calibrated actual data 5,[12][13][14][15]19) for various PV-powered vehicles.…”

Analysis for the Potential of High‐Efficiency and Low‐Cost Vehicle‐Integrated Photovoltaics

“…Necessity of preventing from temperature rise of VIPV modules and effectiveness of developing high-performance solar cell modules with good temperature coefficients is shown in our recent article. [11] The effects of partial shading upon VIPV modules have been studied by some groups [12,13] that are dependent on the sun's altitude, climate condition, and location; shading objects such as buildings, houses, trees, poles, and others; and driving and parking conditions. The effects of the curved surface of the VIPV upon output power of solar cell modules have also been studied by some groups.…”