Inductive Charging for Electric Vehicles
A reader notes: There are presently companies that sell an accessory that allow you to charge an EV wirelessly; regardless of the hype it is not the first system. It is also anticipated that we will be able to charge vehicles wirelessly while they are moving and this will perhaps be the eventual trend. It is only a matter of political will and investment in infrastructure. Here’s an article on the subject.
Yes, that’s true. Personally, I’m not sure these will ever see commercialization. A colleague of mine who runs a start-up in this arena back in Philadelphia says that people are afraid of conductive chargers. There’s a problem with this statement however, i.e., it’s not true.
Maybe we’ll one day have inductive chargers in our freeways. At this point, there is no way to know if that will happen, but it’s certainly not a bet I would be willing to make due to the enormous scope of the project and the dozens of major potential points of derailment.
Here’s an example that came up just a few hours ago: The idea that ultra-capacitors will soon be able to deliver a 1000-mile range. I don’t know anyone anywhere who wants to drive anywhere close to that in a given day.
The article said nothing about cost or efficiency. I don’t doubt that it could be made to work but the number of road coils necessary plus the cost of the high frequency inverters and devices to activate coils when vehicles are over them would be very high. I also suspect that the efficiency would be low. We’ll just have to wait and see what happens.
The publication which contains the information as a number of other “astounding” articles which leads me to question its reliability.
While I don’t have an article in front of me I have seen several claims of over 90% for wireless transmission efficiency. But we have to keep in mind that there are several ways to transmit energy wirelessly. The headline of this article speaks about induction. Induction is what has been used for over a century. It is what we see in almost every power supply and transformer that is made. A coil of wire produces a magnetic field which induces a current in another coil of wire. When the coils don’t match voltage is changed.
The truly interesting form of wireless electrical transmission however uses capacitors to tune the coils. This allows the coils to be more widely separated with less energy loss.
Safety is always a concern but because the energy transferred is magnetic and not electrical the process is considered safe enough to be used in many implanted medical devices and increasingly RFID chips. In any event wireless charging is probably safer than having a extremely high voltage power cord draping from an EV to a power point. (In addition to being far more convenient, just park and press a button)
While a wireless system is likely to be safer, more convenient, ultimately cheaper and potentially more efficient, as you point out Craig, there will be problems with other competing charging infrastructure that may seem better at one or more of these things. Most other options would be hosted by some form of private enterprise where some profit was to be made and political favors more easily bought and sold.
In the US, which is less likely to embrace such a social benefit, batteries and Ultra caps although likely more expensive in aggregate will probably be the norm. Other countries with a greater social consciousness are looking more seriously at wireless transmission for electric vehicles (Europe, S. Korea, and the UK.)
There is a difference between a wireless power coupling system in which the sender and receiver are stationary and accurately aligned and one in which the receiver is in motion. It may well be possible to transfer power efficiently in the former case but achieving acceptable efficiency in the later case would be much more difficult.
Frank, you may be somewhat correct. I have done a lot of reading in the field but admit that some aspects remain unfamiliar to me. I do know that there are about 5 different ways that we try to transfer wirelessly. (Radio waves, lasers, sound waves, induction and using tuned capacitors) Nature also uses gravity, electromagnetic radiation and magnetism.
The essence of induction is an expanding and collapsing magnetic field. The transfer of energy has movement as essential for the induction of an electric current in the second coil. I would then think that a moving vehicle might take advantage of its movement rather than it necessarily being a disadvantage.
For entertainment purposes here is a little toy train that seems to be moving with no power applied at all. The secret is reveled at the end of the video: https://www.youtube.com/watch?v=GHtAwQXVsuk&nohtml5=False
Breath,
The laws of physics cannot be changed. However, sometimes ways are found to take advantage of the laws of physics that had not previously been considered.
But as for efficient wireless transfer of power to moving vehicles, it seems to me that doing it efficiently would require a huge number of coils embedded into the pavement and some sort of switching arrangement. That would probably be exceedingly expensive.
While the concept of building charging infrastructure into highways has been explored, (even experimental strips have been built), logistically the concept is unfeasible, impractical and unnecessary.
Advocates of such schemes always demands vast amounts of public money be wasted on pursuing these sort of grandiose projects at the expense of more humble, but more useful and practical accomplishments.
On site, stationary wireless charging is an excellent method of popularizing EV’s. My wireless charger operates perfectly, charging the vehicle while garaged automatically without me having to remember to plug-in etc. It’s safe, convenient and easy for anyone to operate, even those without a knowledge of EV requirements.
Convenience sells !
I think you’re right in this particular case, though I believe that government support of good ideas in cleantech is essential to our success.
Craig,
Absolutely ! Governments have a duty to assist worthwile R&D and early commercialization, but governments must also spend public money with great care and wisdom.
Imagine how long it would take to electrify a significant percentage of highways with an inductive charging capacity. And, until a significant percentage of highways were so equipped, cars designed to utilize it would not be able to. So even if it were technically practical, in practice it would be necessary to spend billions of dollars repaving the nation’s highways over a period of decades before the technology would be usable. By the time the project was finished the technology might even be obsolete.
I can’t imagine how mobile charging could be done efficiently especially at highway speeds.
There are two companies doing stationary EV charging that I am aware of now.
Momentum Dynamics in Malvern, PA
http://www.momentumdynamics.com/momentum-dynamics.html
and
Hevo in Brooklyn, NY
http://hevopower.com/
Yes. I happen to know the Momentum Dynamic people. I respect them, but I’m betting against them. The problem they solve at great expense isn’t all that large.
I actually work in Malvern now and while I was job searching I sent them my resume. I don’t think I ever heard a response. I know they are there but I don’t actually follow them.