10 ms·
Wirelessly charging electric cars as they drive
- TheSpiceIsLife 7y ago> The wireless transmission takes only a few milliseconds – a tiny fraction of the time it would take a car moving at 70 miles an hour to cross a four-foot charging zone. The only limiting factor, Fan said, will be how fast the car’s batteries can absorb all the power. Well, yes, moving tens of kilowatt-hours of energy in milliseconds wirelessly to a moving target with a lithium based rechargeable battery is an unsolved problem. Who woulda thunk.
- sp332 7y agoI think you would have more than one charging strip. I mean charging your batteries to full in four feet at highway speeds would be cool, but just supplying four feet worth of energy every four feet would be fine.
- cogman10 7y agoThe problem is cost and complexity. These things need a load of copper wire to make a loop, so if you are laying something like this down every 4 feet, it translates into a boatload of material (think 400ft of copper per 4ft charge) (That is being driven on... so definitely a possibility that they require regular maintenance).
- fulafel 7y agoCapacitors and doing a more reasonable amount of energy per charging plate is the obvious interpretation of the engineering.
- jrlocke 7y agoThis article presents the functionality as new, but wirelessly charged electric vehicles have been in use at small scale for many years: https://en.wikipedia.org/wiki/Online_electric_vehicle https://en.wikipedia.org/wiki/Online_electric_vehicle
- thegagne 7y agoOr smaller - bumper cars. Or smaller yet - slot cars. (Not technically wireless or battery powered, but still)
- el_don_almighty 7y agoIsn't this just a miles-long induction stove top? What keeps the rest of the metal from heating?
- vikramkr 7y agoIt's really interesting, but I wonder if as a society we're willing to complicate our roads to the level of adding any sort of functionality to them. Asphalt is wonderfully easy to work with, just pour, grind up, remelt, you can keep reusing it. Even then maintaining our roads is a challenge. Adding electrical infrastructure to the roads themselves to further complicate how you would re-pave, resurface, etcetera? Even if technically feasible, I don't know if we have the economic/political feasibility that's also required to make that work
- asdff 7y agoEven building a bus or a bike lane is highly controversial in the U.S.
- hhs 7y ago> Even if technically feasible, I don't know if we have the economic/political feasibility that's also required to make that work It’s a good point, though outside the US there are also entrepreneurs. Politics/regulations might work differently. There could also be incentives to do things like this.
- ashtonkem 7y agoUnclear what the benefit is, given the cost. EVs already provide enough range for commuting. The vast majority of the population commutes tens of miles, and EVs can regularly do hundreds of miles. So there’s really no need to modify roads for the sake of commuters. For longer distance travel we really should be talking less roads and more high speed rail. They’re faster, safer, and more efficient than cars. It’s also a less uncertain technology; there are several countries with highly successful high speed rail systems that we could copy. For freight we should use regular rail for similar reasons, plus the fact that using semi trucks, diesel or EV, creates a large financial burden on the public to undo the damage that heavy trucks do to our roads.
- battery_cowboy 7y agoThis will be used for some niche use, like a closed road for dump trucks to run full time, or on train tracks for electric trains. This is too complex even compared to putting a cable in every parking space that currently exists.
- davedx 7y ago“Indeed, the magnetic fields can transmit electricity through people without them feeling a thing.” Pretty glib considering the current 5g controversy
- deleted 7y ago[deleted]
- berbec 7y agoPretty glib considering the non-factual current 5g conspiracy theory
- hawski 7y agoWhether it is factual or not is irrelevant for the public outcry over the next conspiracy theory. I'm not defending it, but we currently have a crisis of science authority. I'm not sure what to do about it though. I wonder if putting the system before lights at intersections would help to buy, so to say, people. If it would be cheaper and more convenient for them directly. I think the problem with 5g is that it is not entirely clear how better is it. Also there are probably more people driving, then using mobile Internet. Or at least more people that would protest such undertaking.
- akira2501 7y ago> but we currently have a crisis of science authority Did science ever carry any authority on it's own? In the last few decades I've been living in the United States, I honestly don't think it has. > I'm not sure what to do about it though. I think what we're seeing now is really organized emotional manipulation on a massive scale. I seriously doubt that any of these conspiracies are truly organic, or if they are, that their current scale is organic. Worse still is it's impossible to determine who is doing the pumping. Is it "activist" groups looking for funding? Is it "corporate" groups looking for legal leeway? Is it bored kids on the internet looking for entertainment? As to what to do about it, I think the answer basically starts with a lot more investigative journalism. We don't do that anymore. It creates a vacuum that allows these groups to thrive.
- xnx 7y agoRentable portable removable gas generators that attach to you tow hitch are also a decent solution for charging on the go.
- berbec 7y agoSmall point - why not just but an ICE car then?
- speedgoose 7y agoMeh. Today's battery technology is better than this IMHO. A 80kWh battery and a network of 150kW fast chargers works very well. I wouldn't use anything gaz related for my electric cars, especially during winter. It's not as reliable, it's more expensive, it smells, and it's more dirty.
- msandford 7y agoI really wish that rather than a thing that hooks onto the tow hitch you could rent a whole trailer with a small ~20kW diesel with a significant fuel tank, extra trunk, and perhaps even a built-in compressor-based cooler. Definitely put an extra receiver hitch on the back of the trailer for an extra bike rack, etc. And probably some kind of a roof-rack as well. That way if you're taking a long trip (when you usually need extra luggage) you can also bring all the other stuff. Skis, food, clothes, bikes, kayaks, whatever it is you're doing. It all goes on the trailer. Yeah it's not all that great that it's burning diesel (or biodiesel or whatever) but if you could convince people to drive strictly electric cars the other 355 days a year I think you'd see big improvements in nearly all metrics people care about nonetheless.
- contemporary343 7y agoA few pieces of context - this builds on the insight that underlies WiTricity - https://witricity.com https://witricity.com - near-field coupling of designed resonators for non-radiative power transfer. Specifically, this can enable very high efficiency wireless transfer in the near-field of resonators, which at these wavelengths is on the order of 1-5 meters. This is qualitatively different from other approaches to wireless power transfer and does have some real scientific insight which originates from the electromagnetics/ photonic community. More specifically, this specific results builds on an insight from the same research group which led to a Nature paper in 2017: https://www.nature.com/articles/nature22404/ https://www.nature.com/articles/nature22404/ - that using an non-linear saturable gain element in a parity-time symmetric configuration enables robust power transfer in a range of conditions such as moving and the presences of obstacles. There's interesting underlying science here that shouldn't be missed for the focus on the application.
- madengr 7y agoInteresting. Several years ago I designed a resonate, near field wireless charging platform and used a simple X5R capacitor; the nonlinearity of the X5R dielectric to provide regulation. As the distance increased, the resonant frequency and Q increased, increasing the potential across the X5R, which decreases the capacitance, changing the resonant frequency. Though I can’t remember if I placed the X5R in series or shunt. Though it mainly helped with regulation depending on current draw of the receiver, it did provide some range increase.
- andygreenwell 7y agoInteresting development in this space this week for WiTricity (the company) is that China is standardizing nationally on magnetic resonance technology for wireless vehicle charging based on WiTricity’s designs and standards work. I’m sure this was an exciting week for my former colleagues there, and congratulations are certainly in order for them. https://www.greencarcongress.com/2020/05/20200508-witricity.html https://www.greencarcongress.com/2020/05/20200508-witricity.... There are academic connections between the group at Stanford publishing this work and the group at MIT that founded WiTricity.
- Animats 7y agoHere's the author's web page at Stanford.[1] Not much there. He published a very similar paper in 2017.[2] The actual papers are paywalled. So we don't get to see how big a coil, or whatever, is needed to get 10W at 1 meter. It's straightforward to do that with a split transformer. Berkeley used to have an electric bus which recharged at bus stops that way. More trouble that it was worth, but it worked. There's an old patent from, I think, GE, for a scheme for long transformers below highway lanes to do the same thing. The practical question is whether this new thing is substantially better. Parity–time symmetry is a concept from quantum optics. The author, from his papers, used to do optical work. There's been work on this in the magnetic domain, but at very small scales, like nanometers.[3] Doing this on a scale of meters is new. No idea whether this makes any sense. None of the non-paywalled papers have anything useful to read. Anybody enough into quantum magnetics to make sense of this? [1] https://web.stanford.edu/~sca/ https://web.stanford.edu/~sca/ [2] https://www.livescience.com/59487-wireless-power-systems-charge-electric-cars.html https://www.livescience.com/59487-wireless-power-systems-cha... [3] https://www.osti.gov/pages/servlets/purl/1356846 https://www.osti.gov/pages/servlets/purl/1356846
- Hortinstein 7y agoOne step closer to F-Zero. On a more serious note, This is really exciting. I would be interested to see how they would bill for this type of charging. https://en.wikipedia.org/wiki/F-Zero https://en.wikipedia.org/wiki/F-Zero
- dogma1138 7y agoMany countries would have to replace the money lost to fuel duty with something fuel duties are a huge portion of the tax revenue in most of Europe and many other countries. So adding a road tax for EVs eventually would have to happen to offset the loss of revenue.
- mpolichette 7y agoHmm, I wonder if there could be an interesting incentive alignment with the transaction of charging cars as they drive along a highway and collecting a tax for improving it. There are other comments about political feasibility, but what if the same system became a way to re-produce the tax for use we originally built into gasoline. Obviously theres a bunch of tax evasion / self charge cases that would need to be considered.
- mothsonasloth 7y agoWhy not Scalextrics on a real life size scale?
- sandworm101 7y agoSo they need to transmit enough enegy to power a moving car, through the road surface, using a reciever small enough to fit on/under a moving car. Ok. That's a huge amount of energy. I hope nobody is trying to use a compass anywhere near these roads. And I would seriously think twice about getting out of your car if you have a pacemaker, hip or other impanted metal device. There is aleady a decades-old system in widespread use for delivering electrical energy to moving vehicles. It isn't rocket science. It's called a "wire". https://en.wikipedia.org/wiki/Trolley_buses_in_Vancouver https://en.wikipedia.org/wiki/Trolley_buses_in_Vancouver
- foxyv 7y agoAn interesting thought would be if EVs carried capacitors that had about a quarter mile of range that could be charged instantly then slowly dumped into a battery as the car travels. Then every quarter mile have a fast charge strip that the car pulls from like a light rail into the super capacitor.
- stickydink 7y agoI visited Monterey and noticed some odd markings on the roads. Monterey has induction charging built into the roads along some bus routes. I'm not sure if they're charging along the way, or just at the bus stops? Either way, it's an interesting application. I'm not sure how wild you could go with this right now, given all the roads that exist already, and the cost that would come along with it. Or maybe the traffic implications of people climbing to get on those free charging roads? But public transit seems like a smart use for this kind of thing. Takes a predictable path, for a (somewhat) predictable about of time, on a loop all day. If you designed it right, perhaps you could drive that bus along that route until it breaks down?
- paypalcust83 7y agowireless power transfer (WPT) technology https://mst.org/news_items/media-invitation-cord-cutting-for-msts-wirelessly-charged-electric-trolley-june-8/ https://mst.org/news_items/media-invitation-cord-cutting-for...
- ChuckMcM 7y agoAnd your mechanical watch stops working every time you pass over one of the recharging grid squares :-) I love the idea of using magnetic inductance to charge at a distance but with all that flux even small loops of conductors might be in danger of generating a serious voltage potential across them.
- cogman10 7y agoIDK why there is so much focus on charging in motion. This has a much better application for parking lots. Dedicate some percentage of spaces as charging spaces and power vehicles at rest. It doesn't need to deliver a high power charge to be useful. Heck, this even makes sense for loading docks/semi. Put these induction chargers at every loading bay and let the electric semis charge while they load and unload.
- toast0 7y agoFor fixed vehicles, using one of the two to seven standardish plugs makes a lot more sense. Giving up 8% efficiency to save 30 seconds over usually 20-30/minutes of dwell time isn't worth it. As mentioned elsewhere in the thread, charging forklifts or something in a warehouse in motion, or while briefly stopped drives up how long you can use an electric powered device, and the added utility pays for efficency loss. Of course, it's easier to add this to cover enough of a warehouse than to cover enough of a highway system.
- samatman 7y agoIt's a shame that the somewhat breathless headline is dominating the discussion. This is a good idea, which hasn't even been demonstrated to work with electric cars and roads. What it has been demonstrated to work for, is robots in warehouses, and in that context it's great: this would allow ~99% utilization and obviate laying out warehouse space for charging docks.
- mNovak 7y agoI highly doubt cars are the actual killer app for wireless charging. At the end of the day, they're usually parked a good amount of time, and are comparably tolerant of extra weight, which makes some form of battery much simpler. I'd look for applications where a system cannot stop moving, otherwise isn't in physical contact with infrastructure / cannot be accessed, or absolutely can't tolerate additional weight.
- hndamien 7y agoExactly. Biomedical devices, electric planes/freight drones, agricultural sensors etc.
- nickpinkston 7y agoDoes the below quote really mean that there's only 8% power drop from the charger to the battery? That too good to be true with a wireless system, even with directional antennae. "In their new paper, the researchers show how to boosts the system’s wireless-transmission efficiency to 92%. The key, Assawaworrarit explained, was to replace the original amplifier with a far more efficient “switch mode” amplifier."
- kube-system 7y agoYeah, 8% at what distance? The inverse square law is a bitch.
- lazyjones 7y agoThis sounds like a waste of energy to me. My favourite highway concept is autonomous electric vehicles connecting to each other physically and forming "trains", where the large factor of air resistance is reduced greatly and cars would negotiate with each other who's expending and who's recouperating energy depending on each car's distance to its target.
- 6510 7y ago[Large] wind tubines by the side of the road can produce a lot of unreliable power efficiently. Transporting it to urban areas adds inefficiency to the unreliable. You need a fair bit of wind to get anything out at the other end. Solar voltaic has its own weird reliability issues but the panel does produce unusable amounts of power most of the day. (if your plan is to transport it) Good weight/kwh ratio batteries are expensive. If you can have the batteries roll along the power source for free the wind and sun could be offered very cheaply. Wireless I dunno, overhead cables or contact rails in the road seem fine. Still costly but reasonable. Pondering this it struck me how wonderful this ancient tech is. https://www.rac-info.nl/lv/images/lvtrekschuitenpaard.jpg https://www.rac-info.nl/lv/images/lvtrekschuitenpaard.jpg Its A horse pulling a boat! We could put rails by the side of the road with drones on them (mechanical horses) hook up any old clunker by its towing ring, cut dramatically into fuel consumption, reduce tire wear and get rid of much of the driving idiocy. It gets more spectacular where you can dump mechanical energy into vehicles while it is available. I have no idea at what speed conventional cars are still usable but I see far less need for a speed limit if everyone drives in formation. If someone hits the breaks the drone can detect it and slow down the car behind it. Perhaps 2 cables, one at the front and one at the back. Charging the battery over cables gets pretty obvious at this point. (there is regenerative breaking too!) To add a final bit of hilarity: If we stop gluing batteries into appliances (ffs?) fit them to the bottom and make them easy to swap by driving over a swapping station... then the fully charged battery is more valuable than the empty one. This can drive the cost per km down below zero.
- 6510 7y agoThanks for the unexplained downvote. Reminds me, we could chain people to rails too! That way we can prevent them from going where they have no business. People like me, or like you! It will revolutionize training schedules. You will be on time for work every day.
- peter_d_sherman 7y ago"Wireless chargers transmit electricity by creating a magnetic field that oscillates at a frequency that creates a resonating vibration in magnetic coils on the receiving device. The problem is that the resonant frequency changes if the distance between the source and receiver changes by even a small amount. In their first breakthrough three years ago, the researchers developed a wireless charger that could transmit electricity even as the distance to the receiver changes. They did this by incorporating an amplifier and feedback resistor that allowed the system to automatically adjusts its operating frequency as the distance between the charger and the moving object changed. But that initial system wasn’t efficient enough to be practical. The amplifier uses so much electricity internally to produce the required amplification effect that the system only transmitted 10% of the power flowing through the system. In their new paper, the researchers show how to boosts the system’s wireless-transmission efficiency to 92%. The key, Assawaworrarit explained, was to replace the original amplifier with a far more efficient “switch mode” amplifier. Such amplifiers aren’t new but they are finicky and will only produce high-efficiency amplification under very precise conditions. It took years of tinkering, and additional theoretical work, to design a circuit configuration that worked." A resonant structure (AKA "antenna") can be thought of as Star Trek's Transporter, version 0.0000001... A resonant coil, 0.0000002... A resonant coil to transport electricity, 0.0000003... Then of course there's this: https://www.youtube.com/watch?v=NB_hF_K_7cc https://www.youtube.com/watch?v=NB_hF_K_7cc 2:28: Montgomery Scott: "What's that?" Alternate Universe Mr. Spock: "Your equation for achieving transwarp beaming..." [He shows Mr. Scott the equation on screen...] Montgomery Scott: "Imagine that! It never occurred to me to think of space as the thing that was moving!"
- kumarvvr 7y agoAny tech that aims to improve something by re-designing roads is bound to fail. It's simply not cost effective. How about truck by-lanes across the country are equipped with electric cables on poles, and trucks have those train type extenders to get charged. Or even charging stations in truck stops. And wireless charging is in-efficient.
- Semaphor 7y agoThis is currently in an extended trial in a few places in Germany. Several kilometers of highway have those overhead lines for electric trucks.