Honda Shows Wireless Charging System at Smart House

Jun 19, 2014
Keisuke Ogawa, Nikkei Automotive Technology
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Honda Motor Co Ltd disclosed a new experiment using a wireless charging system to the media June 16, 2014.

The experiment is conducted at a smart house that the company is testing in Saitama City, Japan.

In the experiment, Honda charges its "Fit EV" electric vehicle (EV). The wireless charging system transmits electromagnetic waves from the power transmission coil installed on the floor of a garage to the power reception coil installed under the floor of the EV. The company expects to commercialize the system in 2016.

This time, Honda combined the smart house and EV with a wireless charging system that IHI Corp prototyped using patented technologies of WiTricity Corp. The system consists of power transmission and reception coils, and power is transmitted from the transmission coil to the reception coil by using the magnetic resonance method.

The magnetic resonance method is one of electromagnetic induction methods. It can efficiently transmit power by using a specific frequency even when the power reception coil is not located right above the power transmission coil or when the two coils are away from each other. When the positional error of the EV is ±10cm in the horizontal direction, ±5cm in the vertical direction and ±2° in angle, the charging efficiency of the system is 80-90%, Honda said.

The output of the power transmission coil is 2.2kW. Technically, it is possible to increase the output up to 3.3kW, which is equivalent to the output with a normal charging method. However, because it requires new legislations, etc, Honda limited the output of electromagnetic waves in the test.

The power converter installed on the side of the smart house increases the frequency of residential electricity (50-60Hz) to 85kHz, and the electricity is transmitted to the power transmission coil. The gap between the transmission and reception coils is designed to be about 10cm. But when the two coils are covered, the gap becomes about 5cm.

Honda considers that, if wireless charging makes it easy to charge EVs, they will be more frequently charged, enabling to reduce the capacity of EV battery.