One of the many features of the new smart phones from that fruitful Cupertino-based company this week was the addition of wireless charging, eliminating the need for power connectors and cords. For technology geeks, the underlying resonant magnetic induction technology, that is the magic behind wireless charging isn’t new, as it has been part of some everyday appliances like electric toothbrushes for years. That the technology is rapidly evolving and poised for even bigger application and applications, such as vehicles, may be the big news and was in evidence at the Qualcomm booth at International CES2017.
According to John Boodhansingh, Sr. Director Product Management for Qualcomm, the wireless charging products they offer feature 90% efficiency (comparing favorably to 95%+ for conductive charging) from AC to DC delivered to the car. Operating at 85 kHz, Boodhansingh indicates that the magnetic field won’t interfere with AM radio nor negatively impact people’s health (e.g the pad only emits power when a car in proximity, not when a human is near). With power transfers at 3.7 kW, 7.4 kW, 11 kW and 22 kW, they have wireless charging technology to suit a range of needs from plug-in hybrid to pure battery-electric cars.
Still, the biggest challenge has little to do with the basic technology, but the challenges of standardizing things like protocols to communicate between the charging pad and the car, identifying cars (e.g. for billing purposes), aligning the car to the charging pad, etc. As this article from FleetCarma points out, the various stakeholders should not repeat the standards issues that have befallen conductive charging.
Still, where this technology will shine is in the pubic realm, as it eliminates the need for clunky cables, greatly improving aesthetics, whether on a city street or in a parking lot. Additionally, by having the charging pad under the surface, it opens up the possibilities for charging in locations that otherwise might not be possible. Beyond the convenience of not having to deal with cables during the charging process, wireless charging is especially suited for the autonomous vehicle future, where driverless cars will automatically find a place to power. As depicted in the images in the above video, alignment is a critical parameter and machine controlled steering needed for autonomy would facilitate alignment.
Some of the images in above video indicate that the ultimate destination for wireless charging may be in roads that transmit energy to electric vehicles. Those images are from a test of dynamic electric vehicle charging (DEVC) performed by Qualcomm subsidiary, Qualcomm Technologies, at the 100 meter FABRIC test track in May, 2017. They were able to charge two cars driving at highway speeds with up to 20 kilowatts of power transfer. According to the press release, testing is ongoing to:
“evaluate the operation, safety and efficiency of energy transfer to the vehicles for a wide range of practical scenarios including vehicle identification and authorization on entering track, power level agreement between track and vehicle, speed and alignment of vehicle along track.”
This is truly an amazing development and seems to be more advanced than other groups with a similar concept. Not said in the press release, but implicit with this kind of approach, is that a road-powered vehicle would need extremely fast-charge capability, such as exhibited in a supercapacitor (see the Fuel Tank of Tomorrow). Further, this type of approach might even eliminate or greatly reduce the need for on-vehicle batteries, reducing vehicle weight and cost.
Of course, there would be the increase in infrastructure costs of modifying roads and the overall operating costs would need to be competitive with alternatives for it to make economic sense. Still, there might be some use-cases, such as closed campuses or subways or electrified trains (eliminating the third-rail danger and ugliness of overhead lines), that could prove-in sooner, rather than later. Who knows where this technology road will lead, but, in some form, it looks like wireless power will be part of the vehicle electrification journey.