Toyota Motor Corporation (TMC) has entered into a technology collaboration agreement with WiTricity Corporation, an MIT spin-off commercializing an approach to “mid-range” wireless charging (distances from a centimeter to several meters), concerning the practical application of automotive wireless charging systems for automotive traction batteries and the promotion of their widespread use. TMC plans to participate in a WiTricity capital increase.
WiTricity’s technology is based on sharply resonant strong coupling, and is able to transfer power efficiently even when the distances between the power source and capture device are several times the size of the devices themselves. TMC believes that resonance wireless charging is suitable for automobiles and aims for its early practical use.
WiTricity’s technology is a non-radiative mode of energy transfer, relying instead on the magnetic near field. WiTricity proprietary source and device units are specially designed magnetic resonators that efficiently transfer power over large distances via the magnetic near-field. The magnetic field can wrap around a conductive obstacle between the power source and the capture device.
The power transfer efficiency of a WiTricity solution depends on the relative sizes of the power source and capture devices, and on the distance between the devices. Maximum efficiency is achieved when the devices are relatively close to one another, and can exceed 95%.
WiTricity is also partnering with Delphi (earlier post).
The collaboration is aimed to accelerate development and eventual implementation of wireless charging for automobiles. The charging of a plug-in hybrid or electric vehicle could be as simple and convenient as parking near an embedded charger at a home or in a parking facility.
In the Toyota Global Vision announced in March, TMC expressed its commitment to leading the way to the future of mobility by integrating automobiles, homes and information technology. Wireless charging is one of the many technologies TMC seeks to develop for the future.