Wireless Charging And Autonomous Electric Cars Go Hand-In Hand

APR 9 2017 BY MARK KANE 14

Wireless charging of the Mercedes-Benz S 500 e plug-in hybrid

The 4th International Electric Vehicle Expo, which was held in March in South Korea, brings a few important conclusions made on the state (and future) of wireless charging technology, and autonomous driving.

The main consideration is that autonomous electric vehicles are interdependent with wireless charging.

WiTricity Wireless Charging

For the future of truly self-driving cars, it is important for vehicles to be able to drive without an occupant – both while hunting for a parking space, and also when refueling – something that is only a reasonable expectation with electric cars…that charge wirelessly.

The big challenge with this notion is to avoid repeating a familiar problem, specifically having conductive charging available via different standards.

Therefore, it was re-iterated that a common wireless charging standard needs to be in place that would not only enable all EVs to charge from all wireless stations, but also allow the autonomous vehicles the ability to utilize all the available stations, and also have the proper protocols in place to align the vehicle over station’s charging pad.

SAE International, which is developing the J2954 standard for wireless charging, is one of the lead standards organizations; SAE has entered a formal agreement for the first time with ISO and is beginning a memorandum of understanding (MOU) with IEC.

Dr. Uooyeol Yoon of the Korea Advanced Institute of Science and Technology (KAIST) believes:

“The issue with conductive charging is though there are plenty of standards, unfortunately many of these standards are simply not compatible. This incompatibility hurts not only the infrastructure, but also the commercialization of the electric vehicle as the customer does not accept not being able to go to a specific charging [spot].”

Jesse Schneider, chair of the SAE Wireless Charging Taskforce said:

“Though is not widely known, that there is an interdependence between wireless charging and autonomous vehicles. For light duty vehicles, under all-weather conditions, the only reliable way to automatically charge autonomous electric vehicles is with wireless charging. The standardization of WPT in SAE J2954, coupled with communications, automates the charging process and helps the vehicle “fine tune” the parking alignment.”

Source: Green Car Congress

Categories: Charging

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14 Comments on "Wireless Charging And Autonomous Electric Cars Go Hand-In Hand"

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Not widely known “that there is an interdependence between wireless charging and autonomous vehicles”? Maybe among the SAE people writing the standard, but it’s an obvious synergy for autonomous vehicles, along with car-sharing. Duh!

I think the synergy is the other way around: good autonomous driving makes wireless charging unnecessary.

If you could get a car to drive into the same spot with the same orientation with low error (say, +-10mm pos, +-2 deg angle), it would be quite easy to make a simple mechanism for a weather-protected connector under the car.

I don’t understand why the wireless charger is not on the front bumper.

The car could pull up to a charger on a flexible post.

The car could pull up and touch or almost touch the post and the charging gap could be very slim or almost zero.

Meanwhile Teslas robo-snake will charge an autonomous, auto-parked car with >350kW… try that with wireless.

That assumes that it will be affordable, that Tesla can get it to work reliably, that it won’t require lots of maintenance to keep it so, and that normal accidents and/or vandalism won’t result in lots of expensive down time/repairs. Every time I look at their snake, I think “Falcon Wing Door” problems times 10 to 100.

Is the efficiency, or lack thereof, on these things capable of improving? If I remember right the best of the best in wireless charging still loses about 15% of its power through the transfer. That’s fifteen bucks lost per hundred spent on power. Then if by some means we ever get to a point where we use EVs to stabilize the grid, another 15% is lost to give back. Then another 15% is lost to refill. That’s a lot of percents.

Kinda negates the whole save the planet idea behind EVs.

Wireless charging is just a pointless gimmick!

@needa losses are down to 6-10%

Thanks Vinson. Been about a year since I checked. That’s good to know.

“something that is only a reasonable expectation with electric cars…that charge wirelessly”

This seems to be a false preset assumption to me. Indeed there is no reason why we would not be able to use other charging systems, including direct conduction based.

Either a snake charger, pantographs or “at level” contacts. Many things are possible.

The other statement, “For light duty vehicles, under all-weather conditions, the only reliable way to automatically charge autonomous electric vehicles is with wireless charging.”, is also completely false.

There is just no justification to tell such a thing and there are no physics laws that would absolutely oblige to do so.

At the contrary, starting with 10% loss and electromagnetic radiation emissions is for sure not the best start.

Conductive charging is far from 100% efficient, you’d probably find that it’s comparable to wireless – and probably less efficient at higher power levels.

Wireless systems must conform to emissions standards.

That is simply not true, conductive charging has no loss at all and if there are line loses those are additional to an inductive charger losses as well.


I like this VW demonstration. Same charger could be used either manually or automatic, when a robot operates regular charging plug. They could install the robotic arm to a rail above a row of chargers, so that single robot could serve several chargers to save cost. Same robot could also use several types of plugs on multi-standard charging station. Could be installed on old charging stations too. Endless possibilities.

This also assumes that autonomous means ride sharing. I can let my car drive autonomously to get me around, but I’m more than happy to plug it in each night. The car is autonomous, but it doesn’t require wireless.

A better reason for wireless would be the reduced impact from vandalism and the convenience. You could imagine wireless chargers in the road surface, at traffic lights, every time you stop at the lights you get a minute or so of charge. Pretty much anywhere you stop, get a bit of charge.

Over the course of a day that could add up to a substantial charge.