Ever since Nikola Tesla invented his Tesla coil way back in 1891 boffins in laboratories have
been tinkering with the basic principles of his creation to try to make wireless charging
a commercial reality. And of course nowadays it is. At least to a limited extent anyway. If you
set your phone down on one of those charging pad thingies or put your electric toothbrush
onto its stand to charge overnight then you are already using wireless charging technology.
So as the world moves ever more rapidly away from internal combustion engine vehicles and towards
electric vehicle alternatives I suppose it was only a matter of time before researchers started
looking for ways to scale up wireless charging as part of that expanding industry as well.
As with all new technological sectors, there have been various different approaches to solving the
technical and logistical challenges involved. Those challenges have proven to be surprisingly
difficult to overcome in any kind of economically viable way but now it looks like we're finally
on the cusp of some major advances. So will wireless charging be coming to a street near you
soon and can it be the catalyst to really democratize electric vehicle ownership?
Hello and welcome to Just have a think. If you could somehow travel back to medieval times and
demonstrate how a light can be illuminated simply by flicking a switch on a nearby wall the good
folks of that era would most likely accuse you of being a witch and set fire to you without delay.
Thankfully electricity is now something that most human beings take completely for granted,
but even by our modern standards this wireless charging thing is next level stuff isn't it?
It works on the principle of electromagnetic induction,
which is one of those concepts that I vaguely remember drawing diagrams of in an exercise book
back in my school days. Essentially if an alternating current is put through a coil of wire
it generates a magnetic field around itself and if another coil of wire is brought into
close proximity then the magnetic field induces a secondary current in that coil. That secondary
current can then be made to do something useful like charging a battery. It works really well
at very short range for things like your phone and the toothbrush, but there's an inconvenient
physical constraint that the science bods call the inverse square law which states that because the
magnetic field radiates out in all directions then its energy diminishes very rapidly over distance,
so induction chargers have to ensure the primary and secondary coils are placed as close together
as possible to get the most efficiency out of the system. That efficiency is also determined
by the alignment and cross-sectional area of the two coils, so the best results are achieved when
the two coils are perfectly aligned parallel to each other with a separation of only a
few millimetres. That's known as the coupling factor. A perfect setup would have a coupling
factor of one. Typical real-world induction charges achieve factors of between 0.3 and 0.6
so scaling that concept up to work properly on electric vehicles that are obviously way more than
a few millimetres off the ground and are often very imperfectly parked has been a significant
technical mountain to climb. At the start of this century research teams including the Massachusetts
Institute of Technology or MIT realized that if you could somehow prevent the magnetic flux from
radiating out in all directions and instead focus it directly just onto the secondary coil
then you might be able to negate the effects of that pesky inverse square law and have a much
more efficient transfer of energy. What they came up with is a pretty complicated piece of physics
known as magnetic resonance. Much of that physics is beyond the scope of my brain and this video
but in basic terms it involves tweaking the resistance, inductance and distributed
capacitance of the coils to make them both operate at precisely the same resonant frequency.
That causes the energy to move from one coil to the other in something more like a tunnel rather
than an omni-directional flux. The consequence of that is far stronger coupling between the coils
with energy transfer increasing to several tens of centimetres. And even better news for EV wireless
charging developers is that the energy transfer turns out to be much less reliant on the coils
being perfectly aligned so overcoming sloppy parking or even charging moving vehicles began
to look like a distinct possibility. As usual then in these market-driven technological sectors the
race is now on to develop the best most commercial and therefore most successful wireless charging
solutions for the hundreds of millions of EV drivers that will exist by the end of this decade.
Over in the States the folks at the U.S department of energy's Oak Ridge National Laboratory or ORNL
have been working on a version of the technology that they refer to as a unique polyphase
electromagnetic coil. They recently licensed the tech to a Brooklyn-based company called HEVO.
They claim a surface power density of 1.5 megawatts per square meter.
According to ORNL that's about 8 to 10 times higher than currently available technology.
That enables very fast hands-free charging and could even see vehicles being charged as
they drive on specially modified roads. HEVO founder and CEO Jeremy McCool said "from only
one device mounted on the vehicle a driver will now have the advantage of wirelessly charging
at all levels up to 300 kilowatts powering their home through a vehicle-to-grid interface and even
charging while driving at highway speeds with grid to battery efficiency of 90 to 96.5 percent. All
of this functionality is built into a vehicle side package the size of a medium pizza box and the
ready-made capability to charge electric vehicles without a human being behind the steering wheel".
They've got competition though, most notably from two other US players -Witricity and Wave. You may
have already heard about Witricity's technology from Matt Ferrell's excellent site visit video
which you can jump over to by clicking up there somewhere. Witricity have been perfecting the
magnetic resonance technique for some years now and in an extremely refreshing break from the
normal proprietary protectionism of most modern tech companies they've actually come up with a
completely interoperable standard and supporting infrastructure that'll allow any automaker in
the world to build EVs with wireless charging capability whether they're producing sports cars
or SUVs. In fact that technology has actually been adopted into a proper industry standard
with the inspirationally catchy title of SAE j2954. The electricity chargers can transmit
through all sorts of materials and obstacles at efficiencies of between 90 and 93 percent
from grid to battery. That means they can be sunk into asphalt roads and driveways
and can even cope with adverse weather conditions like snow and ice cover.
Witricity see a huge opportunity in the fledgling autonomous vehicle market
including robotaxis. Human beings won't want to get involved in the running of these new vehicles,
we'll expect to simply summon one with an app, get in, travel to our destination and get out again.
So Witricity have coined the term 'power snacking' for autonomous vehicles of the future. Taxis will
queue up at ranks that have induction charges below the surface and each time they return to the
back of the line they'll pick up a bit of extra charge. And the same thing could be installed into
dedicated taxi and bus lanes in urban settings so the vehicles are sort of grazing on energy all day
long while they're on the move. That means they'll be able to keep going throughout the day without
any costly stoppages at stationary recharging points. WAVE is an acronym that stands for
Wireless Advanced Vehicle Electrification. They're owned by a Nasdaq listed company called Ideonomics
and they're focused on extreme fast charging systems for the medium and heavy duty end of
the market with a proposal for charging speeds of up to one megawatt from subroad wireless charges
using the same magnetic resonance techniques we looked at earlier. WAVE are partnering
with Tesla to get their receiver boxes factory fitted to the new range of Tesla semi trucks
whenever they finally hit production. If the hype around these new electric trucks is true then they
look like they'll dominate their market, and that probably means Elon Musk will launch himself with
characteristic gusto into the challenge of installing the charging highways across the
United States that'll be needed to support the wireless charging technology rollout...
apparently he's going to be the world's first trillionaire soon isn't he, so I guess he's got
a few bucks that he can throw at the problem. BMW launched a wireless charging pad for their 530e
model back in 2019 claiming the prize of becoming the first automaker to have this technology
actually available to buy but the 530e is not a fully electric vehicle it's a hybrid so with
the best will in the world the charging pad was really nothing more than an expensive trinket that
BMW owners could show their friends when they came around for dinner. This little beauty is called
the Genesis GV60 and it's the first all-electric vehicle with genuine wireless charging capability.
And it's not a bad looking thing either is it? Genesis is a South Korean car brand but they've
chosen Witricity's technology for their wireless charging system. That's pretty much exactly the
opposite way that technology advances have been flowing in recent years and it represents a big
win for a pioneering US company. According to Genesis the car will carry a 77 kilowatt hour
battery that can be fully charged with 270 miles of range in about six hours via the wireless
charger. That compares very favourably with 10 hours using a domestic wall mounted charger and of
course if you're on the hoof you can just add 50 or 60 miles in 15 minutes or so. The Genesis GV60
goes on sale in South Korea at the end of 2021 and it'll be available in the States in mid-2022.
One of the most important advantages of these wireless home charging systems is their ability
to help stabilize grid frequencies as electricity demands continue to rise in the future.
A battery is most useful to the grid when it's full of charge, but car owners with wall mounted
chargers are unlikely to plug their vehicle in when their batteries are full - why would you?
That means the grid can't get at the very useful energy source sitting on the driveway or in the
garage. With induction charging you won't be plugging anything in so as long as you park
your car over the charging pad the grid will be able to access your car's battery automatically
without you lifting a finger. There are still naysayers who claim that electric vehicles aren't
practical and that they get their electricity from fossil fuel power plants and anyway they'd fry our
grid systems if everyone had one and on and on and on... and there will always of course be laggards
in any normal distribution curve. If those people had lived 150 years ago
I suspect they'd probably have been dismissing the automobile as a useless impractical fad
that would never replace the horse and cart. It just demonstrates a lack of open mindedness
and vision for how new technologies can and do disrupt existing systems.
The reality is that electric vehicles are rapidly gaining in popularity among the buying public
and they are here to stay so the quicker these complementary technologies can be rolled out the
quicker we'll all transition to a more sustainable energy future. No doubt you've got your view too
so the place to share that is down in the comments section below. That's it for this week though.
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