What is it and how does it work?

In the years that EVs have existed, numerous developments and innovations have been made. However, one of the most exciting innovations has finally arrived: wireless EV charging.


As wireless charging technology for EVs becomes more advanced and more widely available, driving into a station to charge your EV may become a thing of the past.


Cutting the cord when charging electric cars

Over the years, there have been technological and logistical challenges in scaling wireless charging technology for EVs. Overcoming these challenges in a feasible and cost-effective way is not an easy task. However, researchers have cracked the code and are now developing wireless EV charging for a street near you.

It’s easy to take wireless technology for granted these days, but it really is cutting edge technology. The science behind the innovation is based on electromagnetic induction. Basically, if an alternating current passes through a coil of wire, a magnetic field will occur. If you introduce another coil, the magnetic field will induce a current to that coil which will charge a battery.

It works well at close range to charge your phone, but there is a challenge. Scientists call this the inverse-square law, referring to how a magnetic field radiates in all directions and dissipates energy quickly over distance. Therefore, primary and secondary coils should be placed close together for maximum efficiency.

The same efficiency depends on the alignment and cross-sectional area of ​​the two coils. The coils must be aligned perfectly parallel to each other, separated by millimeters, the so-called coupling factor. While 1.0 is considered a perfect coupling factor, real world applications only achieve a coupling factor between 0.3 and 0.6. Scaling this up to apply to EVs that are higher off the ground and not properly parked presents apparent problems. MIT researchers and others have been working on a solution and developing technology to counteract the inverse-square law.

The years of study resulted in the discovery of magnetic resonance, where the resistance, inductance and distributed capacitance of the coils were adjusted so that they both operate at the exact resonant frequency. As a result, instead of going from one coil to another in all directions, the magnetic field follows a straight path.

Magnetic resonance strengthens the coupling between the two coils, increasing the overall coupling factor. This makes wireless charging possible for buses and trucks that are higher off the ground and vehicles that are parked in a way that you can break your head over them.

Wireless charging of electric vehicles is key to switching from ICEs

Despite the key benefits of driving an EV, there are still concerns for potential EV buyers. The main points of attention are the range of electric vehicles and the ease of charging. It is important to make charging effortless. Having a convenient and effective way to charge EVs will get more people on board with the transition.

As electric vehicles become cheaper to manufacture and purchase due to lower battery costs, an EV charging solution must be installed for the millions of EV owners over the next decade.

More and more countries are switching from vehicles with a combustion engine to electric ones. The supporting infrastructures are therefore growing rapidly. Electrify America, Tesla Superchargers and EVgo are among the largest electric vehicle charging stations in the United States and the race to develop the best, most cost-effective commercial wireless charging systems has begun.

Companies race to bring wireless EV chargers to the masses

Oak Ridge National Laboratory (ORNL) has developed a unique multi-phase electromagnetic coil, while Brooklyn-based company HEVO has been licensed for this technology. According to ORNL, the unique multiphase electromagnetic coil delivers the highest available surface power density, 1.5 megawatts (1,500 kilowatts) per square meter – eight to ten times higher than currently available technology. This allows for fast charging while stationary, and even has the potential to recharge while driving on modified roads.

HEVO founder and CEO Jeremy McCool said:

With just one device mounted on the vehicle, a driver now has the advantage of wireless charging at all levels up to 300 kilowatts, powering their home through a vehicle-to-grid interface, and even charging while driving. driving at highway speeds with mains electricity. – to battery efficiency of 90-96.5%. All this functionality is built into a vehicle-side package the size of a mid-sized pizza box and the out-of-the-box ability to charge electric vehicles without a human behind the wheel.

The automotive world will change faster this decade than it has in the last century, and we need a step change in EV charging to unlock the full potential of this burgeoning multi-trillion dollar industry.

HEVO faces stiff competition to produce wireless EV chargers in the United States. Massachusetts-based WiTricity also specializes in wireless EV technology. It is a spin-off of MIT and was founded in 2007 by Professor Marin Soljačić.

WiTricity technology enables wireless charging of electric cars at home using a wall-mounted electrical box connected to a charging pad on the floor. Charging starts automatically as soon as an EV with receiver drives over the pad. WiTricity says the wireless charging pads can be installed on the ground, such as in a private home, driveway, or parking garage; or in the ground, buried in the sidewalk of a parking lot or curb as public charging infrastructure.

“Charging via the plug is difficult, dirty, unreliable and even dangerous. The answer is wireless charging by WiTricity for EV owners today, and definitely for autonomous vehicles tomorrow. If there is no driver, who will connect him?” said Alex Gruzen, CEO of WiTricity.

GOLF is another company impacting the wireless charging market. The abbreviation WAVE stands for Wireless Advanced Vehicle Electrification. It is owned by Ideonomics, a company that makes fast charging systems for medium and heavy vehicles.

Ideonomics claims that WAVE’s powerful systems are suitable for powering electric vehicles in mass transit terminals, warehouses, distribution centers, shuttle services and seaports.

Tesla has partnered with Wave to install receiver boxes on its semi-trucks as they become available. Tesla is very optimistic about the project. If successful, Elon Musk could embark on the formidable task of installing wireless charging highways across America to support the technology.

Is wireless charging of electric cars the better way?

As the growth and popularity of EVs increases, there will be plenty of opportunities for technology companies to develop solutions to support them. Wireless charging allows EVs to trickle charge all day long, solving the problem of EV cable charging and range anxiety.

Charging electric vehicles via wireless technology is at the forefront of the industry’s advancement. Going forward, companies such as HEVO, WiTricity and Wave will continue to fill the gaps of what is needed to keep the future of not only EVs, but autonomous vehicles bright.

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