Basic Study for Materials of Tire and Wheel for Dynamic Wireless Power Transfer System with In-Wheel Coil

Dynamic wireless power transfer (WPT) can solve the short-cruising range problem of electric vehicles. Energy transfer is one of the major problems of dynamic WPTs. Prevention of the entry of foreign objects physically be-tween the transmitting and receiving coils is the best way to increase energy transfer for dynamic WPT. This research proposes a novel WPT system, named in-wheel coil, which can transfer through the tire and the wheel. The suitable materials of tires and wheels for in-wheel coil is also evaluated and proposed. Metal belt of tire is not efficient and rises temperature of tire. Instead of metal belt, fiber belt which has no conductivity is proposed and proved that it does not has any influence for WPT system at 85 kHz. This research also revealed that steel and aluminum and cross carbon fiber reinforced plastic (CFRP) has critical influence for WPT performance and uni-directional (UD) CFRP has little influence for WPT performance at 85 kHz. Combination of the wheel made of UD CFRP wheel and the tire whose belt is fiber belt is the best way to improve WPT efficiency.