Imagine a day when charging is as simple as pulling into a parking space. No cords to untangle or trip over, nothing to get your hands and pants dirty and nothing to wrap up when you're already late leaving for work. Just park your car, and forget it. That's the beauty of charging wirelessly through electromagnetic induction. It's still a nascent technology, though - as least when it comes to electric vehicles - and not without its problems.

The induction coils are usually placed in the ground, and the car parks on top of it. Due to the gap between the charger and the car, the coils need to be very strong, and thus large, to charge the car. This makes inductive charging installations prohibitively expensive. Furthermore, the warmth emitted by the coils attracts small creatures looking to snuggle up under the car, interrupting the charging. Despite the wireless charging systems currently installed in electric vehicles being declared safe, some people may worry about things catching fire, which is obviously less than ideal.

With a working charger already built, the challenge now is to make it more powerful without making it bulky.

That's where Fraunhofer Institute for Integrated Systems and Device Technology (IISB) comes into play. Researchers at the IISB have developed a charger that may solve some of these problems. They have developed an upright inductive charger that stands in front of the car. Without a large gap between charger and vehicle, the coils can be much smaller (the ones on the car fit within the dimensions of a license plate), and objects are less likely to impede charging.

Researchers realized that pulling close to the charger could be tricky, so they made it out of plastic that won't damage the car. Also, the charger tilts backward and eventually flips down as pressure is applied, so both car and charger remain undamaged in case of contact. According to IISB's Dr. Bernd Eckardt, his group now has "a prototype that is able to transmit three kilowatts (kW) at an overall efficiency of 95 percent. Today's electric car models can be recharged overnight."

With a working version already built, the challenge now is to make the charger more powerful without making it bulky. Also, the IISB would like to be able to build the charger at a lower cost to make it more commercially viable. Should it become available, it could be a convenient answer to the problems of the charging cable and in-ground inductive chargers alike. Read more in the press release from Fraunhofer IISB below.
Show full PR text
Charging electric cars efficiently inductive

Research News Jul 30, 2014

We already charge our toothbrushes and cellphones using contactless technology. Researchers have developed a particularly efficient and cost-effective method that means electric cars could soon follow suit.

Cables are fast disappearing from our daily lives. The computer mouse has already lost its tail, our telephones and headphones have become wireless – even electric toothbrushes and cellphones don't need cables anymore. Information is transmitted wirelessly, and power needs can be met via an electromagnetic induction supply system. Researchers are in the process of developing wireless charging technology for electric vehicles, too. "Cables are annoying, especially in winter or when it's raining. Whatever gets on the cable – snow, sludge, water – also gets on your hands," says Dr. Bernd Eckardt, head of the Vehicle Power Electronics department at the Fraunhofer Institute for Integrated Systems and Device Technology IISB in Erlangen, Germany. Dr. Eckardt knows what he's talking about, because he drives an electric car himself. It would be much more convenient to charge these plug-in vehicles remotely with contactless technology. And it's possible. The way to do it is using electromagnetic induction, whereby electrical energy is transferred over the air between two objects via an electromagnetic field. Dr. Eckardt explains the physics behind it as follows: "Any wire that carries a current generates a magnetic field. As the English physicist Michael Faraday demonstrated in the 19th century, this magnetic field generates voltage or electromotive force as well. By correctly positioning two wires in relation to one another inside a magnetic field, it is possible to transmit energy over the air. In principle this works just like a transected transformer." Familiar examples of products that use this kind of energy transfer include charging stations for electric toothbrushes and smartphones, and induction hobs.

Researchers from the scientific and industrial communities have been working for several years to find ways to use induction to charge electric vehicles. The current approach involves mounting induction coils on the underside of the vehicle and installing charging stations in the ground. But this brings with it a number of significant challenges. The coils need to be very powerful for the method to work because of the significant gap of up to 15 cm between car and ground. Powerful coils are large in size – and large coils are expensive, which pushes up costs. There is also the problem of objects or animals impeding the charging process by blocking the transmission of power. Cats, for example, are attracted by the gentle warmth emitted from the charging station in the ground, and so see this as a comfortable resting place. Another particularly problematic issue is that metallic paper such as chewing-gum wrappers or cigarette packaging can blow under the car and into the induction zone, where it can get so hot that it bursts into flame.

Researchers at the IISB began pursuing an alternative approach in a bid to resolve these problems. Working as part of the Energie Campus Nürnberg research platform it took them less than a year to develop a system for charging electric vehicles from the front end (http://www.encn.de). Since this allows the car to be driven much closer to the induction source – essentially touching it – the coils themselves are much smaller in diameter than in the floor-based version, coming in at 10 instead of 80 cm across. The system is more efficient, more cost-effective and makes it less probable that obstacles will disrupt the flow of energy. The charging column is approximately waist-high and made of plastic. It bends backwards if pushed by the vehicle, and is even designed to flip down and out the way if the pressure applied is too strong. "The car could drive over it if necessary. Touching the charging station causes no damage to the car body," says Eckardt. The coils are arranged in such a way that charging can take place even if the driver has not positioned the vehicle exactly in front of and centrally to the column. Clusters of coils that overlap vertically in the column and horizontally behind the license plate allow the current to flow irrespective of the vehicle's size or height.

Scientists at the IISB have been working on power electronics for electric vehicles for some twelve years now, and have been researching inductive charging for the last two. During this time they have accrued extensive expertise in the fields of power electronics, field simulation and current distribution within electromagnetic induction systems. In order to keep exchange resistance to a minimum, for instance, they designed coils that themselves consist of several thin coils each insulated one from the other. The design of the wire coils is important because it is the coils that determine the direction and strength of the magnetic field. "We've been consistently upping the system's performance over the past year, and are now in possession of a prototype that is able to transmit three kilowatts (kW) at an overall efficiency of 95 percent. Today's electric car models can be recharged overnight," says Eckardt. The researchers are now looking to further increase the power of the coil, primarily to keep up with developing battery technology, and to cut the cost of the charge spot even further. "Nowadays, charge spots are offered as part of the sales package when customers buy an electric vehicle. This technology will only become a mass product if the price is right," Eckardt explains.


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    • 1 Second Ago
  • 44 Comments
      SublimeKnight
      • 4 Months Ago
      Having to pull in and be perfectly aligned with a wireless charger seems like it would be an overall time wash with getting out and plugging in. You are getting out of the car anyway, right?
      Marco Polo
      • 4 Months Ago
      i wonder how sensitive the on-board charging connection is to minor front end collisions ?
        DarylMc
        • 4 Months Ago
        @Marco Polo
        Hi Marco Polo Inductive charging seems to rank second only to fuel cells for passionate comments here. Personally I don't see wireless charging as a necessity. It's probably something I could never justify but that doesn't mean I think they shouldn't exist. What is impressive about this unit is that they claim to have improved the efficiency, size, cost and weight. I still think it could be done a lot better. Having this gadget permanently cluttering a garage floor or car park seems worse than having a cord on the ground while a vehicle is charging. Even worse for parallel street parking. This also applies to every other wireless charging base which protrudes from the ground. I like the idea someone else mentioned of raising the base or perhaps even better lowering the plate on the vehicle. Especially if closing the gap improves the efficiency as this one appears to claim.
      DarylMc
      • 4 Months Ago
      One more thing. My dislike of automatic transmissions and of course my weariness of changing gears after 30 years leads me to very much appreciate the beauty of a single speed drive in EV's.
      DarylMc
      • 4 Months Ago
      Does anyone else notice that a lot of the issues in this press release have been discussed at length in ABG comments? It's almost like they used it as a source.
        DarylMc
        • 4 Months Ago
        @DarylMc
        I wasn't complaining. It's just interesting to see mention of cats and foil wrappers. The previous comments on the topic were very diverse.
        kent
        • 4 Months Ago
        @DarylMc
        Small animals and fire are a big concern from wireless charging? What comments section have you been reading? Nobody here would suggest a touchless plug thats less efficient a plug.
          DarylMc
          • 4 Months Ago
          @kent
          I've been reading the comments on ABG articles about wireless charging over the last few years. Whether it is an issue or not, cats and vandals covering the charging plate with foil certainly were in the discussion.
        Mart
        • 4 Months Ago
        @DarylMc
        What? People who try to market product might do market research? The devil you say.
      Letstakeawalk
      • 4 Months Ago
      I enjoy manuals too, I'm not knocking them at all. I also prefer manual windows, and manual seat adjustments. Likewise, even living in the southern united states, I can personally attest that air-conditioning (vital for children and the elderly) isn't that big a deal for a typical healthy adult. Modern conveniences, though, and so all are generally standard equipment on the typical USDM auto. How much weight could have been saved on the Tesla by simply having manual seat adjustments... That said, you are correct in pointing out that manuals are very rare in the US. I recently rented a 26-ft truck, and even it came with an automatic. Our licensing doesn't discriminate - one license no matter what sort of transmission you test on, and you're allowed legally to operate the other. So, choosing an automatic transmission here isn't a matter of paying more (no manual option anyway), nor is it a matter of giving up efficiency either (ABG posted a really nice article about how modern automatics generally beat manuals in mpgs now). Most people who choose a car with a manual are searching for a particular *connection* with a car, because of enthusiast predilections. I completely agree with that, I'd love to have a manual in a lightweight sports car, for simply tooling around on curvy roads on a sunny afternoon... but that's not really the ABG line is it? Wasteful indulgence! http://green.autoblog.com/2010/08/18/greenlings-why-do-automatic-transmissions-now-get-better-fuel-e/ I like the drivetrain on EVs too. But that's not the part of your comment that I was referring to when I called you a rarity. "In 30 years driving I've never considered an automatic transmission a luxury I could justify and I've never owned one." I don't think there's very many other people out there that could say that. I can't think of one person I've ever met that could say that. Certainly not in the US. You're a unicorn, DarylMC. Be proud.
      Marco Polo
      • 4 Months Ago
      @ DarylMc Yes, I agree, there's nothing like a convenient, labour saving device for rousing the indignation of purists with a strong puritanical aspect of their nature. No doubt when the 1913 Cadillac was first displayed equipped with an electric self-starter, there was a group of stern faced critic, with arms folded, and grim frowns of disapproval, avowing that "it'll never catch on, real motorist don't mind cranking their machines ! " My LERR is equipped with inductive charging, and it works extremely well . (no fires, suicidal small animals, bolts of lightening, etc :) Like automatic transmission v manual, it's just a matter of personal preference, I guess.
      DarylMc
      • 4 Months Ago
      Hi Letstakeawalk I read that autoblog article about the efficiency of modern auto transmissions a while ago but I was a bit sceptical. If you don't have many vehicles with manual transmissions in the US it's hard to directly compare but here in Australia most auto's use a bit more fuel than their identical manual counterpart. That is why I mentioned the Volkswagen DSG. Ford and some other manufacturers also have dual clutch transmissions in their range. If you are not familiar with them you should have a read. There are essentially two manual gearboxes and two clutches with computers operating the gear selection and clutch action. Some but not all of them claim better fuel economy than their manual equivalent. Then there is CVT's which are not that common here in Australia. There is every reason to think they can offer good performance and fuel economy compared to manual. I think they are well proven in the Japanese market but may people are wary of them here.
      DarylMc
      • 4 Months Ago
      Marco Polo I don't believe you about being lazy. It does put you in a position to describe the pros and cons. How do you find the gadget.
      • 4 Months Ago
      Imagine a day when those inductive chargers were under the road you drive on, alleviating or erasing the need for the most expensive, heavy, and resource-critical component of all future automobiles.
        Larry Holmes
        • 4 Months Ago
        What should be built under the road you drive on is a traffic sensor that detects vehicles on the road around you and adjusts your vehicle performance to avoid collisions and allow unfettered acceleration according to conditions. It should also perform an autopilot function that give you hands-off driving.
          Ashton
          • 4 Months Ago
          @Larry Holmes
          @ Larry - I couldn't disagree with you more. In case you haven't noticed, those technologies are being implemented in vehicles, not the roads. Having sensors in the roads if far more expensive, and you would constantly be having issues. Lets take one example using your horrible idea. We've built a stretch of the interstate system with all your in ground sensors, its the middle of summer, a bunch of family's are traveling for a vacation. They are cruising along on auto-pilot and not paying any attention to the sensor filled roads. But being summer, the intense heat has made the road buckle, severing the connection of your "smart road". Next thing you know hundreds are dead in the biggest pile up ever created, all because someone thought it was a good idea to have the sensors IN THE ROAD.
        Grendal
        • 4 Months Ago
        As if we don't have enough things around us radiating energy. All for a very slight gain in convenience in the case of inductive charging.
        Ashton
        • 4 Months Ago
        yeah...no thanks. 1. That would cost a fortune! 2. You could only drive on the roads with it built-in. 3. That would cost a fortune! As for this system, it seems pretty good. If they can make it cheap enough it'll sell very well.
          • 4 Months Ago
          @Ashton
          Expensive? Compared to what? Batteries, right now, are the most expensive component in an electric car. And the heaviest. Imagine every car on the road being electric. Why have millions of expensive, heavy batteries rolling along the road, doubling the cost of each vehicle, requiring a national lithium recycling effort, and limiting total range? Stanford U says that the efficiency of rolling inductive charging will work, saying one could arrive at one's destination with more charge than when one left. If our energy future is all renewable, and built as a Federal project, we might well afford to be able to make that electricity free of charge. That way, fossil fuels don't have to be regulated, they could just be made obsolete as a power source.
          Greg
          • 4 Months Ago
          @Ashton
          I'm not convinced that it needs to be that much more expensive. First, don't eliminate the batteries from the cars (they will need them anyway to access driveways, parking lots, etc.). Since the cars have batteries, in-road charging is only needed to overcome range issues. Only install the in-road charger in one lane of hwy thoroughfares. EV drivers stay in that lane if they want to have charging, and that keeps them out of the way of the rest of traffic. Installing this system doesn't change many costs of building roads: no surface roads are affected; cost to buy right of way is unchanged; cost to prep soil is unchanged; cost of building bridges/overpasses is unchanged; cost of building all but one lane each direction is unchanged. The only delta is what it would take to add this to one lane on just the highway thoroughfares. The additional costs could be paid for either as part of billing for the electricity or by savings elsewhere. How much does it cost to install chargers in every parking lot, job site, etc? Maybe the size of battery packs could be reduced slightly. Money saved in those places could cut costs for the in-road system. That being said, I doubt I'll ever see in-road charging because of the inherent losses of induction charging. I just don't think it will be efficient enough.
      Marco Polo
      • 4 Months Ago
      @ DarylMc "Should I bump you into the bone lazy category or just a technology enthusiast:)" Lazy !:)
      Len Simpson
      • 4 Months Ago
      airbag the floor model, reduce the size accordingly
      DarylMc
      • 4 Months Ago
      Hi Marco Polo In 30 years driving I've never considered an automatic transmission a luxury I could justify and I've never owned one. Never was really happy with the job they did compared to changing gears as I see fit. Probably a bit like the folk who think paying extra and sacrificing a few percent efficiency is heresy. I didn't know you had induction charging on the LERR. The feedback from people using this stuff is really of interest to me.
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