Sumitomo Electric developed the small superconducting motor and successfully demonstrated to drive the electric passenger car. The motor power is around 30kW and the torque is 120Nm. The superconducting motor will enable to get larger torque, reduce the space and get higher energy efficiency.
[Purpose of prototype development]
Superconductivity allows electricity to be carried with almost zero electrical resistance. This means that low loss conduction of high density currents is possible, and superconductivity is therefore attracting much attention as a new energy saving technology.
Sumitomo Electric, who has been carrying out research on practical applications of high-temperature superconducting technology for various areas of industry, developed a bismuth-based superconducting wire that offers the world’s highest level of critical current(*). With this development, Sumitomo Electric is participating in various projects related to superconducting technology, such as a high-temperature superconducting cable demonstration test in the U.S. and a Japanese industry-academia project on the development of ship-propulsion superconducting motors.
One possible practical application of high-temperature superconductors is use in electric car motors. With an intention of proving the feasibility of using superconductivity in automotive motors and getting superconducting technology known widely in industries and society at large, Sumitomo Electric prototyped the world’s first superconducting electric motor cars using its comprehensive high-temperature superconductivity technology.
[Features of superconducting cars]
A standard electric car motor uses coils made of copper wire. Because copper is readily heated by electrical resistance, a copper wire conveys only a limited value of current, which means that it is difficult to obtain a large torque. A superconducting wire, on the other hand, can conduct electricity with zero resistance, allowing a large current to flow through without a loss. By using coils made of superconducting wire, a superconducting car makes it easier to continuously obtain large torques and use energy from the battery efficiently, thus contributing to energy saving compared with a standard electric car.