I also have a lot of trouble believing in the scenario of a neighborhood that has an automated charging station for EVs but no grid. That seems like very misplaced priorities.
You can kind of just leave them exposed and live.
None of that applies to a 220V, 50A (or whatever amperage) charging. That can absolutely kill somebody; jet fuel may not melt steel beams, but 11,000W sure will.
You’d end up needing some kind of recess probably, and then getting cars to connect to it like planes refueling mid-flight is a nightmare. You could try some sort of USB-C like signaling before power is sent, but people are never going to enjoy “exposed 220V contacts that may or may not be live depending on if things malfunctioned”.
Planes refueling mid flight is hardly an apt metaphor given the charging station isn’t moving at all and the car can move as slowly as needed.
Surely getting something to autonomously without fail extend an arm and plug in for the lifespan of these vehicles vs just park in this allocated spot you would park in anyway is an obvious tradeoff.
I also frankly do not believe the 90% efficiency claim because it seems so much higher than any other wireless charging I’ve heard of.
This seems like one of those things that seems cool but is not generally practical. As a convenience for wealthy Porsche EV owners, sure. As a general purpose charging solution? I doubt it.
Starting a fire, maybe, cooking an animal, extremely not likely.
Turn on an induction stove to max. Put your hand on it. Did it burn your hand? No. Put a ferrous pan on it. Suddenly, really hot.
Same concept happening here. A 36" induction stove top is likely putting out about the same inductive power. If the risk of being over the pad while it operated was enough to burn someone, so would cooking food on an induction stove.
If you put a chicken breast in a microwave oven and turn it on, it will rapidly cook. If you stand next to a radio antenna emitting hundreds of watts you can potentially get burns. These things use electromagnetic radio fields (E + H) to blast energy out, and those fields can stably radiate out on their own.
Inductive cooking and charging is radically different. If you put a chicken breast directly on an induction cooktop and turn the cooktop on, nothing happens. The unit doesn't even really increase its energy usage, because there is no load. This is because this energy transfer is relying on just the magnetic fields (H). It relies a lot on the target being harmonically in tune, and the other side needs to actually be conductive and at least somewhat magnetic. Non-magnetic materials don't couple with these magnetic fields. This is why some pans (like aluminum and copper) "don't work" with induction cooktops.
So if a cat did climb on the charging pad, maybe some parts of the collar would energize and heat up.
If animals were significantly affected by things like wireless charging pads or inductive cooktops we wouldn't be able to survive MRIs.
Regardless, your MRI comparison is very apt. MRIs use similar amounts of energy for scanning and do sometimes cause burns. But no one seems to be getting cooked.
> that the transfer is via electromagnetic waves.
An induction charger doesn't transmit its energy through electromagnetic waves. That's what I'm saying. It's inducing a current through magnetic fields. Its a very different process. If the material isn't magnetic it doesn't react. Which is why a steel pan heats up very rapidly while your hand is cool, why an induction stove doesn't use much electricity at all when there isn't a pan on it to heat. If it worked by emitting RF, it would have the same power output regardless of the pan type. Which is like your microwave, if the magnetron is energized it's putting out 1,000W regardless of what you have in there.
A radio is emitting its power regardless of if there's an antenna on the other side tuned to receive it. If there's nothing on the other side of the inductive charger, there's no load, there's no power usage. You need something able to receive the power to actually transmit the power. With that something being how well it reacts to magnetic fields.
So while I buy the distinction between magnetic coupling and propagating EM waves, it seems that there is some risk.
Maybe at 11kW+ of effective power delivery these fields are enough to actually make eddy currents in your blood enough to cause damage. There's a decent chance it could cause neurological disruptions while in the field. But once again, its really not the same kind of thing as RF radiation emissions, and how these things will affect you is pretty different in the end.
Those two things really aren't comparably difficult. Eg in the dumbest case for pads, you could make the pads slightly smaller than axle diameter (to prevent dead shorts) and have the car randomly jostle around the space until it detects current flow. I've seen some amateur systems that work vaguely like this. Some signal that charging is nearby, and then a semi-random search to find exposed contacts.
That's not going to cut it on a recessed outlet. Your odds of hitting it randomly are tiny, and it will probably the damage the port with enough repetitions of ramming it into the floor.
> Planes refueling mid flight is hardly an apt metaphor given the charging station isn’t moving at all and the car can move as slowly as needed.
Change your reference point to the plane carrying the fuel and they get an awful lot closer. The planes are moving a lot relative to the ground, they're moving very little relative to each other. I'm not sure if you've watched them doing it, but relative to each other it's actually a very slow process.
Why would it be random? The scenario here is self driving cars. Suddenly we are talking about random jostling instead of actually targeting.
> Change your reference point to the plane carrying the fuel and they get an awful lot closer. The planes are moving a lot relative to the ground, they're moving very little relative to each other. I'm not sure if you've watched them doing it, but relative to each other it's actually a very slow process.
What is your point here? I’m totally lost. You seem to be trying to hand-wave away the difficulty of refueling mid flight. The specific difficulty there is the fact that it’s happening at high velocity, not the difficulty of plugging a hose into a port. (Traditional mid air refueling is manually directed anyway.)
You are probably fully capable of fueling your car at a self serve gas station. Try doing the same at highway speed. Just reach out the window of the vehicle you are in and fill up your friend’s car from a gas can. Should be easy since the cars are “moving very little relative to each other”, right?