GM patents EV that can charge and power stuff simultaneously
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Outside the obvious uses in a fleet scenarios, there are some more niche use cases.
One use case could be if you are carrying a second large battery pack for something. It may make sense for large non-vehicle battery packs to adopt the car based charging standards if they're intended to be towed or put in the bed.
One use case could be if you are carrying a second large battery pack for something. It may make sense for large non-vehicle battery packs to adopt the car based charging standards if they're intended to be towed or put in the bed.
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The patent covers essentially all the possibilities of what an intermediate car could be doing. It could pass DC along. It could use DC to charge its battery, converting to AC for a daisy chained car that doesn’t support DC, etc.
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There are EVSE s that allow multiple cars, but don't add to the service load. They just split the available service between loads (or cycle from one load to the other automatically).
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I think this is the most exciting scenario for GM. If they get the patent on this, imagine the sales opportunity to a company trying to electrify their fleet? 1 plug per 3 vehicles (or more) is much more appealing than 1 per.
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When I read about it elsewhere they indicated this was aimed mostly at fleet owners.
They could reduce the number of chargers they need, and/or the amount of shuffling in and out of chargers they would need to do. They daisy chain them up and walk away...
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At scale, it would be much cheaper for this to be built into the power circuitry of a car than the cost of a second standalone charger.
On the other hand, most people with two EVs would probably just buy the second charger anyway, so having charging electronics in the car would be an extra cost they’re not utilizing.
I could imagine it being something that only ends up on utility vehicles like pickups and vans.
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So a lot of people may not realize that a building's floor plan may limit charger placement to one side or the other. It's expensive to have an electrician come in and add extra power lines to accommodate something like this. Existing wiring has to be considered, how the existing wiring is routed, etc. Some houses this is relatively easy. Others it's not. Even if the installed charger has multiple ports it may not be conveniently installed in a place that can run the charge cable for two vehicles at once.
For example, many older model ranch style homes have a car port with either 3 walls or only two. The wall in front of the vehicles may have a fireplace in the middle which makes it unsuitable for placing a charger, especially if it's a brick hearth (the brick will act like really rough sandpaper). The other internal wall is the only suitable choice meaning you'd have to run a charge cable across or under the first vehicle to charge the second. That's extremely inconvenient. The longer the charge cable run, the more loss you get. The outer wall would have the same problem, if it even exists. So a charge pass through would be quite desirable.
The other configuration is to mount a charge station on the ceiling, which has its own drawbacks, such as weight load and the inconvenience of having to remember to walk around any dangling cable (ever turn around and accidentally walk into something you forgot was there?). Also keep in mind that if you use a reel store like some shops do for extension cords, you're setting up an inductive loop electrical engineers may not have accounted for in the charge circuit.
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Then you have to drag your daisy-chain cable around with you and fumble with plugging into other people's cars when you park and unplugging from them when you leave, breaking the chain if you're not the last one in line. And charging for all the cars in the chain will be limited by the current of the single EVSE and the lowest current EV upstream from you, either what their capable of passing through if it's just putting all the cars in parallel or worse, whatever their onboard inverter is capable of spitting out if they're going through the charge circuitry of each.
This seems like an incredibly stupid solution to getting more EVs plugged in. Just deploy more EVSEs. That can't be what whoever drew up this patent has in mind. Or maybe it was and this is one of those cases of just patent the idea because you had it but with no intention of ever doing anything with it.
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I would suspect the most useful time for this would be for fleets where the number of vehicles you need to charge at any time can vary wildly. So you can delay having to jog cars around the parking lot by daisy-chaining a bunch of cars together. That way, you don't have to move that first car until you actually need to move it. Even if it is fully charged, it can just relay the power to the next car down the line.
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It's not even that novel, except for "doing it on a car". Uninterruptible Power Supplies have been doing this for ages. Pulling in mains power charging battery banks and simultaneously using a separate set of hardware pulling a load off the banks to power equipment.
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The "charger" is not actually a charger. It's essentially an extension cord with a contactor in it that makes sure the plug is only energized when connected to a car. All the expensive bits are already in the car. All this does vs an EVSE that can balance between two connected cars is move the "second" EVSE into the car that's sharing. That's assuming it's not chaining through the battery. If it is, then this is worse than just a split EVSE because there's a second AC-DC conversion plus a DC-AC conversion just to charge the second car which is just stupid.
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You still need all the electronics of a charger. It has to talk to the car, split off power, etc. All the same stuff a wall-mounted charger is doing.
You’re probably also doing AC/DC conversions for isolation, regardless what power the subsequent car wants.
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That’s fair, but many folks can’t feasibly modify their garage. Think renters or folks that live in an apartment where there’s fewer chargers than cars.
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The way this is usually done is to install (for example) one 50A 240V feed into the EVSE which has two car cables, and then the EVSE tells both cars "you're connected to a level 2 charger and you're allowed to draw 20 amps". Both cars say "sure" and, together, draw 40 amps, so the EVSE and the circuit breaker are happy. Then car 1 finishes charging, so the EVSE tells car 2 "ok, you can take 40 amps now if you like".
Daisy-chaining isn't useful when you have control of the fixed infrastructure. Doing it as described above is easier and better.
Daisy-chaining might be useful when you do not have control of the fixed infrastructure. Two people show up at a hotel that has only one free charge port. They face off like angry gorillas, posturing for dominance, and then one says "wait, my GM supports charger pass-through, so how about my Silverado takes the EVSE and you plug your Mach-E into mine's pass-through port, and both will be fully charged by morning." And the fight is averted.
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The "charger" is in the car being charged in any AC charging scenario. The EVSE is very simple. Even the "communication" between the car and the EVSE is just a square wave from the EVSE and a charging resistance between the control pins by the car to request different currents. That's it. The actual business of taking that power and charging the battery is all handled in the car via an onboard charger.
In the best case, this is simply adding an EVSE to every car that can output. Worst case, it's that plus a beefy inverter to pull from the battery, even if it's just passing along from upstream, and all the losses that come with that at every step in the chain. That would fucking suck because you're going to lose a kW or two pretty easily by the time you get to the third car. That's a lot of power to just turn into heat for no fucking reason.
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It would not be hard to build a splitter that did that. Plug into an EVSE and tell it that you want 40A service, then have two downstream CCS/NACS ports which tell the cars that they can only draw 20A each, with a microcontroller to watch the load currents.
Put that splitter inside a car and you get one upstream and one downstream port, which is what this patent is discussing.
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Hopefully it's also flexible enough to let you use which ever port you want to charge the vehicle when you are just charging and only using a single port. That seems almost mandatory to avoid customer confusion and frustration. That would allow you more flexibility on how you park while charging and eliminate the worst case situation where charger placement doesn't go well with vehicle port location.
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Charging off of a generator seems like a use as well. Construction crews, road maintenance, etc.
One generator, multiple vehicles, let the systems sort things out.
Maybe extended V2L? Two vehicles, one load, load has two vehicles worth of reserve.
One generator, multiple vehicles, let the systems sort things out.
Maybe extended V2L? Two vehicles, one load, load has two vehicles worth of reserve.
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And how is that different than that the car needs all the same electronics as an EVSE? It either does need them or it doesn’t. What you’re saying is now “if you limit to AC charging, those electronics aren’t very complicated”, which is a completely different statement.
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Kind of covered above, but I can see a few use cases:
1. A business is mandated to have 4 EV charging stations to cover their parking lot of 40 stalls. 20 employees have EVs. This allows for all vehicles to charge while employees are at work.
2. You're going on a road trip in multiple vehicles. You don't need to fully charge any of them, but you need a quick 30 min stop to charge up a bit while you all eat. The restaurant has 1 free charging station.
3. You do an activity that requires a mobile power source, and you usually use your second plug as that power source. Let's say you're a landscaper who works at a number of small parks. This new system lets you plug your EV into the charging station at the park at the same time that you're supplying power to your equipment.
And that's just 3 off the top of my head.
1. A business is mandated to have 4 EV charging stations to cover their parking lot of 40 stalls. 20 employees have EVs. This allows for all vehicles to charge while employees are at work.
2. You're going on a road trip in multiple vehicles. You don't need to fully charge any of them, but you need a quick 30 min stop to charge up a bit while you all eat. The restaurant has 1 free charging station.
3. You do an activity that requires a mobile power source, and you usually use your second plug as that power source. Let's say you're a landscaper who works at a number of small parks. This new system lets you plug your EV into the charging station at the park at the same time that you're supplying power to your equipment.
And that's just 3 off the top of my head.
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If upstream is plugged into an EVSE, you just pass through AC. If car A is charging cars B and C with no grid connection, A's onboard charger runs in reverse (V2L mode) to generate AC to send to B, and then B passes through AC to C. You never have unnecessary conversions, and cars with V2L can do this already with a splitter EVSE as I described above. There may be some additional handshaking so that the cars can see what's going on with the SoC of each other's batteries.
If you have two cars connected you could also DC to DC charge, using the V2L to make DC at the right voltage for the second car, but that needs inverter support in the car (a switched smoothing capacitor) and to generate the right signaling for DCFC to talk to the second car.
All of the hardware is already there to do this, aside from the downstream-facing second socket - the rest is software.
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Are EVSE's actually required to monitor the power? From my understanding, they tell the car how much power it may deliver and the car is responsible for not going over that value.
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I'm clearly not following you at all. Or you're saying the same thing as me.
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If you have it on the back of the vehicle, it might be useful if you have an electric trailer with an onboard battery. Use a single EVSE to charge both, then have the trailer charge the BEV when the BEV's drive battery is low.
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It's not clear from the article or the (useless) patent pictures how it works. I didn't go look up the patent, so maybe it describes it better.
But I covered both ways it can work. Either it simply passes AC through, making each car effectively an EVSE (woo hoo, so exciting, just put the second fucking EVSE on your garage wall), or each stage does convert for no fucking reason which would be apocalyptically stupid, and I wouldn't even expect GM to come up with something that stupid. But then I also don't really see the use case for this "solution" besides maybe very small fleets where you only have one EVSE but you have two or three vehicles to charge overnight? Seems like it would have been easier to spec an EVSE capable of charging three cars, or three EVSEs that can load balance on a single circuit, and then you don't have to worry about which order the vehicles leave in the morning.
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If you have 3 cars charged off of one AC connection, doesn’t there have to be some logic somewhere keeping total current to 1x instead of 3x?
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I want a PHEV to go camping in, and as a backup to live in if I can't afford rent. This would be great to run the heat in winter or AC in summer while connected to shore power for charging.
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The more current you pass through a circuit the larger the conductors to handle the load and heat sinks must be to disperse the heat build up, yes. Basically you just have another switching supply in the vehicle.
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The point being that you can’t just wire it so that if charging on AC, the three cars are just running in parallel off the same EVSE. You need some kind of power management system in there.
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That doesn't bother me much, presumable the cars would negotiate a power level that's safe for both -- doesn't seem any different than plugging into a stranger's EVSE (like at the hotel), you have to trust that it's not going to blast 480VAC down the port when your car only asked for 240V.
But you do have to trust that a stranger that moves his car breaks the chain of charging cars takes the time to plug in the next car in the chain after he moves his car (and hope that the cable is long enough that he can complete the chain.
Seems more suited to fleet charging than random strangers with various cars at a hotel.
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I absolutely want this so I can plug an EV truck into shore power at an RV campsite and then power my trailer from my EV.
I was just looking at doing the opposite - running my trailer off shore power and installing a ln EV charger on the trailer to send power to my EV.
That said, I want to get a Silverado EV for this summer and I doubt the feature would be available by then. So I’ll have to stick with my current plan.
I was just looking at doing the opposite - running my trailer off shore power and installing a ln EV charger on the trailer to send power to my EV.
That said, I want to get a Silverado EV for this summer and I doubt the feature would be available by then. So I’ll have to stick with my current plan.
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I would point out that one patents implementations, not ideas (at least in theory). Having said that, I didn’t see anything in the patent that wasn’t just how you would obviously tweak the concept of pass-through for the existing specifics of how EV charging works.
Basically, you need to output power to the downstream car in a manner that it would expect from an EVSE, and that power comes from the battery and/or an upstream EVSE. Once that’s the concept, it’s just rather straightforward circuit design. Even if there were some clever circuit design that might be patentable, that does not seem to be what’s in this patent.
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Each car would also be an EVSE effectively. It could either tell the downstream car "tough shit, no power right now" until it has finished charging or "ok, I'm capable of delivering X Amps" while it's pulling 2X and sending half to the battery and half down to the next car (or some other split). Of course this means daisy-chaining another car results in those cars getting a quarter each and the first getting half, and that quickly becomes pretty useless, so they might want to implement something smarter where the downstream cars can tell the upstream cars how many are connected so they can either do a more fair split or do some kind of priority queue.
E: typos, typos, typos
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In theory, you could even charge the downstream cars from a combination of the upstream car’s battery and the power it was receiving from its EVSE, depending on which batteries you were more interested in being charged faster. I would suspect, though, that in practice that kind of fine control wouldn’t be implemented. The first car in line would share out wall power if plugged in or use its own battery if not plugged in, if for no other reason than to keep the UI simple.
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YetAnotherAnonymousAppellation
Ars Tribunus Militum
How about charging the battery (or reducing the discharge rate) by supplying power from a trailered (or in the truck box) gasoline generator rig. You essentially get a PHEV setup where the Hybrid portion is external and you attach it only when needed.
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Just a note on a misunderstanding common in these types of threads. EVs charging with "DC" don't get a constant DC voltage, 400V or 800V. They get a variable voltage near that basic voltage, which changes while the battery charges or discharges. Hook a fixed DC voltage to an EV battery and you'll probably fry it, unless the safeties prevent you from doing it. You can't just tie a DC solar system, or DC from another EV or battery, and use it to charge an EV. You need a DC-DC convertor, which is just as expensive as an AC-DC convertor. If you have 16 charge ports at a supercharger station, they will all be putting out different DC voltages, each controlled by the charge state of the EV that port is tied to.
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Fleet owner scenarios makes the most sense to me.
But personally, he road trips scenario is compelling to me. I do a lot of trips with friends where we meet at a destination cabin or beach house, and we try to find places with at least one EVSE or at least a 240V outlet, since there are multiple BEVs and PHEVs involved. Having N cars with this passthrough charging would simplify things greatly.
Charging at a workplace where I can possibly trust coworkers to daisy chain would also great. My partner had a massive chat group with other EV owners at her last job for coordinating charges.
Even just friends visiting my home for the evening and wanting to charge their car a little bit — I’m not saying I would always tell them to plug into my car rather than the wall charger but I’d appreciate the flexibility.
“Engagement clickbait” indeed. But this is a great idea.
But personally, he road trips scenario is compelling to me. I do a lot of trips with friends where we meet at a destination cabin or beach house, and we try to find places with at least one EVSE or at least a 240V outlet, since there are multiple BEVs and PHEVs involved. Having N cars with this passthrough charging would simplify things greatly.
Charging at a workplace where I can possibly trust coworkers to daisy chain would also great. My partner had a massive chat group with other EV owners at her last job for coordinating charges.
Even just friends visiting my home for the evening and wanting to charge their car a little bit — I’m not saying I would always tell them to plug into my car rather than the wall charger but I’d appreciate the flexibility.
“Engagement clickbait” indeed. But this is a great idea.
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Yeah, if you see some of my later comments, you'll see me arguing that the intermediate cars still need to be actively managing the power they pass along, even for AC power where you'd need to make sure the combined current draw does not overload the circuit. I guess maybe the only exception would be if the intermediate car is fully charged it could, at least in theory, passively pass along power and control signals.
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