Development of 2nd-Generation Solar Charging System and Generating Performance in the USA

In response to the steadily worsening impact of global warming, greater efforts are being made to achieve carbon neutrality. Toyota Motor Corporation developed an in-vehicle solar charging system that utilizes generated solar energy to drive the vehicle. While the ignition is off, energy generated from a solar panel is used to charge the main battery. Then, while the ignition is on, this energy is supplied to the 12 V system to reduce consumption of the main battery energy, thereby helping to improve the electric driving range. This 1st-generation solar charging system adopted in the Prius PHV in 2017 was the first mass-produced in-vehicle solar charging system in the world. In 2022, the 2nd-generation solar charging system was developed and adopted in the bZ4X, including performance improvements such as a newly designed solar roof and lightweight charging system. However, further enhancements are necessary to facilitate the adoption of in-vehicle solar charging systems, as well as to help achieve carbon neutrality. Therefore, the 2nd-generation solar charging system has been adopted on the new Prius Prime and launched in the USA for the first time in 2023. Eight representative cities in the USA were selected under the Köppen climate classification, and the annual and monthly energy generated from its solar panels was calculated from solar radiation data. As a result, the performance of the 2nd-generation solar charging system was calculated in the USA and found to show high product value. This paper introduces the development of the 2nd-generation solar charging system and the performance generated from its solar panels in the USA.