Toshiba tests wireless charging electric bus
Toshiba has begun testing its SCiB lithium-ion battery and contactless charger for electric buses in Tokyo. The cable-free charger uses a magnetic resonance system instead of electromagnetic induction, using a pad in the ground over which the bus parks. It charges the 45-passenger bus's 52.9-kWh battery pack in about 15 minutes, providing about 55 miles of driving on a single charge. The battery provides high output, allowing for highway speeds, and retains its performance after many charge and discharge cycles.

The 45-seat bus is powered by a long-life, high-output 52.9 kWh SCiB ( earlier post ) pack, Toshiba’s advanced lithium-ion rechargeable battery, and will make regular trips between All Nippon Airways Co. Ltd. facilities in Tonomachi, Kawasaki and Haneda Airport in Tokyo. The 11-kilometer (6.8-mile) journey will test the bus and its performance under various traffic conditions, and will allow Toshiba to verify the convenience and practicality of contactless charging, along with its contribution to reducing CO 2 emissions.

Toshiba Corporation has developed a fast, cable-free contactless charger for electric vehicles (EVs), and will field test it on a medium-sized EV bus designed to handle the power demands of regular high-speed journeys on expressways. Field tests will start from 1 June and continue until December.

The contactless charger, designed in collaboration with Professor Yushi Kamiya of the Faculty of Science and Engineering at Waseda University, replaces conventional electromagnetic induction with a magnetic resonance system that is installed in the ground, under the bus. The system is easy to operate; charging starts once the driver pushes a button on the bus dashboard.



Charging pads. Click to enlarge.

Distance between the transmitter and receiver is 10 cm, with an alignment tolerance of up to up 20 cm widthwise and up to 10 cm lengthwise. Charge time is approximately 15 minutes. Travel distance per charge is approximately 89km.

Tests have verified that the system’s radio emission level meets limit regulations and do not interfere with radio signals of nearby equipment.

The SCiB battery of the type installed in the test EV bus is rugged, reliable and has a long life, showing almost no fall-off in performance even after 15,000 quick charge and discharge cycles. It is highly suited for use on shuttle buses operating at locations such as tourist sites and airports, which must combine heavy use with frequent and fast charging. It takes only 15 minutes or so to charge SCiB to a level necessary for the EV bus to run one-way between the test sites.

The battery also delivers high output that, combined with improvement in performance of drive components allows the bus to achieve a top speed surpassing that required for safe operation on expressways.

Development of this system has been supported by the Ministry of the Environment under its Low Carbon Technology Research and Development Program since 2014. A field test that deployed a small EV bus incorporating a similar charging technology started in February this year and will run until December.

Toshiba will continue research and development of contactless charging and other advanced technologies that contribute to reducing environmental loads, and work to improve the quality of urban transport by providing SCiB for various transportation systems.