WiTricity Working On Wireless Charging At 10s Of kW

SEP 15 2014 BY MARK KANE 16

The WiTricity power source, left, is connected to AC power. The blue lines represent the magnetic near field induced by the power source. The yellow lines represent the flow of energy from the source to the WiTicity capture coil, which is shown powering a light bulb. Note that this diagram also shows how the magnetic field (blue lines) can wrap around a conductive obstacle between the power source and the capture device.

The WiTricity power source, left, is connected to AC power. The blue lines represent the magnetic near field induced by the power source. The yellow lines represent the flow of energy from the source to the WiTicity capture coil, which is shown powering a light bulb. Note that this diagram also shows how the magnetic field (blue lines) can wrap around a conductive obstacle between the power source and the capture device.

New WiTricity CEO Alex Gruzen stated that the company, besides working on base 3.3 kW and 6.6 kW wireless charging solutions, is developing much more capable versions with 10s of kilowatts:

“In addition to the 3.3 kW system [the power level of charging EVs] we also have a 6.6 kW solution. And we have work underway to to go to 10s of kilowatts. It’s a broadly applicable technology. As the cost [of batteries] comes down, and the size grows, right in parallel, we are going to higher and higher power transfer. We just march in lock step with industry development.”

With $25 million in funding obtained late in 2013, WiTricity established a lot of partnerships with Delphi, Toyota, IHI with Mitsubishi Motors, and TDK, which sooner or later should help introduce the first electric cars with WiTricity’s wireless charging.

Maximum efficiency of wireless charging exceeds 95%.  However devices must be relatively close to one another and 3.3 kW WiT-3300 is at 90% now.

Maybe because of its partnership with Toyota, or maybe not, Alex Gruzen sees the future of wireless charging in plug-in hybrids:

“The convenience is extraordinary. In many of these vehicles, the battery is relatively smaller. At every point today with a plug-in hybrid, you are presented with a choice of when I pull in to the garage, do I plug in now or not plug in now. When the batteries are smaller [as in plug-in hybrids], you are not getting all the fuel economy benefit if the battery is not fully charged. The relative value for the plug-in hybrid is the easy topping off of the battery. I feel like there is [potentially] a real catalyst for dramatically improving the core user experience.”

Demonstration of Toyota Prius Plug-In with wireless charging:

Green Car Congress

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16 Comments on "WiTricity Working On Wireless Charging At 10s Of kW"

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To me, “10s of kW” is a no-mans-land of undesirable charging. If I am charging at home, 1.4kW is enough for me. Others may need 3.3kW or even 6.6kW for their commute. If the battery is sized large enough for most days (very important!), then the car only ever needs to charge overnight.

On the other hand, less than 100kW is undesirable for charging on the road. I want to stop for minutes – not hours – when I’m charging on the road.

Don’t get me wrong, I would much rather have 20kW than 3.3kW. But I wouldn’t make a habit out of 20kW charging on road trips either. And I think the majority of the car-buying public would agree with me.

This lifts them to the same levels as are typical of the fastest non-superchargers.

For instance the Zoe can charge at 44kw.

At this point they are looking to PHEVs, and if your battery pack is low in those a 15 minute charge would restore your pack for the journey home.

100kw plus is the next stage, and no doubt they have got their eyes on it in due course.

“10s of kW” is intentionally vague. Interesting that you read 44kW into the claim. I was thinking more like 20, because that is the upper limit of the J1772 standard (80A at 240V = 19.2kW). From this article, I don’t know whose guess is closer. But my point still stands. And it’s worth pointing out that the first two words of my post were “for me”. I’m one data point, and do not claim to be representative of the majority. I’m still not sold on the idea of wireless charging. It has its place for sure, but it feels more like a luxury feature than a true enabler. It cannot yet match the charging rates of a wired system, and so all it adds is convenience. I don’t think that physically plugging in the car is what is holding people back from buying an EV. I think it is the amount of time to recharge, coupled with the difficulty of finding a charging station (relative to finding a gas station). This doesn’t help with either. In fact, it could make the latter worse because now you have yet another standard with which your car may not be compatible.

I chose that point because I happened to have it on the top of my head, without looking it up, and because other fast charging standards are converging up to something like that.

They specifically say that they are looking to be comparable with wired charging, so I guessed that if practicable they are possibly looking to reach similar levels.

But they don’t say, so your guess is undoubtedly as good as mine! 😉

Actually, my best guess is that they are working on a couple of different power levels, to see how it goes.

One of around 20kw, and one of 40-50kw.

Its normal to have a couple of versions under development at the same time, at different levels of readiness.

I think “10s of kW” would be ideal for charging while driving. Install these things in the roadbed on every major interstate. My Leaf can maintain highway speeds with very little power. If the battery could be recharged while driving on a long journey, I’d have no need for a bigger battery, no need for CHAdeMO…and no need to stop at all, actually. Maybe for the bathroom.

Interstate wireless charging makes a lot of sense, but few states have tje financial or political will to make it happen. Add to that the lack of a single wireless charging standard, and it’s a no-go at present. 🙁

3.3 or 6.6 wireless charging at home whenever the car is parked, and at work, at school, could handle all the charging needs for over 80% of the daily commuters.

Inductive charging is definitely the way to go.

If you need to drive further than battery capacity on a daily basis, buy a EV with a larger battery capacity.

Once 200 mile EVs are the base models in a few years, this whole obsession with public charging will end.

Wireless charging is nice but I would like to have a secured contact based system as well. The development of this doesn’t seem to follow the 100 % yield interest that it would bring. The roomba, the grass mower all use that simple secured contact based system to recharge so there is no reason the under side of a car could not have a similar system to recharge with 100 % yield, secured and no manual plugging required. The power can be whatever and eventually can even be hypercharge because removed from manual interaction.

That sounds like a lot of sense.

This is how some electric busses charge, however you have added some complexity to the system.

I’d rather give up 5-10% of charging efficiency for the KISS approach. The more moving parts you have and things that need to seal due to the environment, the more problems you are going to have.

The grass mower has no sealing system and it charge fast at not such a small power. There are also no moving part but at most some flexibility from the metal contacts. A car can drive above a small bump underneath and have flexible contacts touching curved contacts above the top of the bump. In that way there is no place in between, no standing water and no risk for a cat. Frankly, I can see no show stoppers except just doing it.

I’m happy to remove every single perceived barrier to EVs

However: is plugging in really that hard? Is it even perceived as that hard?

“Oh my god! I have to walk ALL the way over there, grab a cord, lug the cord ALL the way back here, and plug it in? And then repeat this in reverse tomorrow morning? I can’t go on!!!!”

I hope they develop this technology. I also hope they keep a cord option. People are afraid to live by power lines and are nervous putting their mobile phones near their heads and their junk due to “radiation” causing cancer.

Just imagine if you told them that the car would charge in a wireless way at 100+kW

I certainly have no intention of having electric windows in my car!
How hard is it to wind up a window? 😉

haha, Touche!

Next car I buy I swear I will ditch the crank start though…..:-0