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Toyota to begin wireless vehicle charging system verification testing

Toyota Motor Corporation (TMC) will begin verification testing of its newly developed wireless battery charging system for plug-in electric vehicles—such as plug-in hybrids and battery-electric vehicles—in late February in Aichi Prefecture, Japan. The system can charge a vehicle parked in alignment over a coil on the surface of the ground, making the charging process simpler and more convenient.

The charging system uses magnetic-resonance technology, which transmits electricity by utilizing the magnetic resonance resulting from changes in magnetic field intensity between a coil on the ground that transmits and a coil on the vehicle that receives.

In December 2013, Toyota licensed (earlier post) the intellectual property (IP) of WiTricity, an MIT spin-off commercializing an approach to “mid-range” wireless charging (distances from a centimeter to several meters, earlier post). Having made an equity investment in WiTricity in 2011 to accelerate the development of automotive wireless charging systems and acceptance by carmakers (earlier post), Toyota has cooperated technically with the company for the past several years.

The system can reduce drops in power transmission efficiency that can be caused by misalignment or height differences between the transmitting coil and receiving coil. Created with future market launch in mind, the system is designed to minimize electromagnetic interference on nearby equipment and the ground-installed transmitting coil is robustly structured to withstand a vehicle driving over it.

Wireless electric vehicle charging system. Click to enlarge.   On-screen display. Click to enlarge.

Furthermore, to enable the driver to park in an optimum charging position, Toyota has developed a new parking assist function that shows the position of the transmitting coil in the parking space. The new function is coupled with Toyota’s Intelligent Parking Assist system.

Quick Specs
Charging method Magnetic resonance
Frequency 85 kHz
Input voltage 200 VAC
Charging power 2 kW
Charging time ~ 90 minutes

The verification test will involve three plug-in hybrid vehicles in use in homes in Aichi Prefecture and is initially planned to last one year. The tests will assess user satisfaction, system ease-of-use, misalignment rates, and charging behavior, such as charging frequency and the use of timer-based charging.

The test results will be used to further develop the technology, with commercialization the ultimate aim. Toyota believes that commercialization will help promote the use of electrified vehicles.


Account Deleted

An important spec is missing: The wireless charging efficiency. As a rule of thumb people who want to sell you something leaves out mentioning all the bad things. That the efficiency is not mentioned by Toyotas press release is as good to me as saying that their technology is still highly inefficient at the 3 foot distance that will enable practical wireless charging.


Wow! 2kw!
That's S-L-O-W charging!
The upside is that it won't damage your battery!


3 feet? What are you talking about?
The car parks over the pad.
The distance is the one from the bottom of your car to the pad, perhaps 10 inches.

They use Witricity technology, so:

'Q: How efficient is WiTricity technology?

A: 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%.'

Account Deleted

If you can park the car perfectly each time. Allow for realistic slack and you get 3 feet. "can exceed 95%" means at most 95.5% efficient at close range. I bet 70% at 3 feet.

Tesla's building home charger is a 20k watt cable with 100% efficient transfer. That is the competitive bar. And it allows you to charge even if the car is parked 10 feet from its normal place. Good for guest charging.


Do read the article.
They are incorporating automated parking so that it will be properly aligned.
Even if you were parking manually I can't conceive how you would miss by the distance you suggest.

I would love to see the cable that is 100% efficient at transferring power.

Account Deleted

ok maybe 99.95% at 10 feet. What is your point.


My point is that you are completely inaccurate in your notions that there would be a 3 foot gap, as the article clearly outlined autoparking and you simply ignored it.
Even at present if you have a system installed in your garage it will beep at you in the way reversing sensors do to ensure correct alignment.

It appears that you just don' fancy magnetic resonant charging, and so are ignoring anything favourable and comparing it with magic 100% efficient charging.

If the Tesla is 99.95% efficient, source your data.

Account Deleted

Na have no time. I know I am right but you are always welcome to prove me wrong.

Bob Wallace

Some cars automatically park themselves. The technology is in place to let cars position themselves over the charger with great accuracy.

South Korean buses are charging while moving using senders buried 8" under the pavement. They report 85% efficiency.

One company that makes wireless chargers reports 97% efficiency with senders glued to the parking space surface.


That is not how it works and you know it.
It is not up to me to disprove your claims but for you to prove them, or at least provide references, as I did to the efficiency of the WiTricity system, and to the transmission distance.
I'm a bit surprised and disappointed really Henrik, as your posts today are not up to their usual standard.
Still, we all have off days I suppose.


"I know I am right"..there is the beginning of some big mistakes through out history.


I'm scared of the risk of cancer from this - the media must investigate the cancer risks!!!!!!


All the investigators died.



Ah yes, wireless charging: a $3000 replacement for a $300 cord. Self driving capability required on the car in order to find the charging sweet spot? Thanks, but I'll park it myself and get my fingernails dirty with the plug attached to a cable.


Good comment, Mr incomprehensible!
All that counts is what you personally prefer, and nothing else is worth noting.
No doubt you also stuck to cathode ray tvs as well, as initially LCDs were a lot more expensive.

william g irwin

Hey guys, no mention of resonant frequency changes or power xfer speeds etc. from manufacturer to manufacturer yet. How well will a volt, Tesla, or Nissan charge on the same pad assuming a compatible alignment? My wife and I (and/or kids/guests) might have 2 or more different PEVs.
Sounds like we may need some standards down the road!


There should not be a problem at this stage of the game, as they have not got far enough along to mess it up with proprietory systems from the car manufacturers!

So the charging pad from, in this case, WiTricity will send the power to the receiver, also WiTricity, installed in each of your cars, which passes it on to the BMS.

It shouldn't be a problem, but that may be famous last words if car makers line up with different wireless charger manufacturers so that only the approved one can get it from the receiver to the battery! :-(


I thought this would be popular years ago. A new EV owner does not mind plugging and unplugging until they have done it about 1000 times.

Roger Pham

We are kept being told that the advantage of PEV is that no new refill infrastructure will be required...that a 120-V home socket will be sufficient.

I see two issues with this wireless charging: The high cost and low power. To justify the high cost, the charging time must be drastically reduced in order to recoup investment cost in due time, for public charging spots.

Otherwise, a 120-V home socket can deliver 1.5 kW of power for zero additional cost. To quadruple the power, a 220-V appliance type of socket can be used, which may already exist in the garage for clothe dryer usage, or in the attic for A/C usage, and can be quickly relocated or duplicated near the BEV for not too much cost.


Wireless charging will be a very appealing option for many future electrified vehicle owners.

Public wireless charging stations could and most probably will be equipped with automatic payment capabilities making it completely hands free.

Autonomous drive future EVs will position the vehicle in the perfect place and move it to an adjacent parking place when charged and call the owner to advise that his/her vehicle is ready to go or pick them up at the door if desired.

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