European 'standard' e-car power connector details emerge Further details have emerged about the design of the would-be European e-car plug standard currently being championed by Germany-based energy company RWE. 02_SM RWE's e-car plug design The plug will support both 230V single-phase and 400V three-phase power supplies for, respectively, in-home and direct-from-grid charging …
A nice aspect (for the tax gatherer) of an universal 'smart' plug is that you potentially have the ability to tax "driving" electricity more, as you can do for fuel.
Indeed, you advocate an universal plug, for convenience. You then make sure that all the charging stations need a license, a meter, and a network connection (for service quality purposes, or "smart grid", whatever), that the car only starts charging when a licensed station is detected at the end of the cable (for safety reasons, of course!), and poof ! Electricity-for-the-car can be taxed as much as you'd like!
The plug present pin has a more serious function. It tells the power source when to power those contacts. This way the possibility of high currents flowing through the plug while it's still not plugged in is eliminated. It's been done for years in simmilar connectors. It's a safety feature.
It needs a facility for locking it in place (with a padlock or the car's key fob). Otherwise, some oik will unplug it for fun and you'll come back to an un-charged car. If both ends could be unplugged he'd walk off with the cable.
Also what happens when it gets dropped into a puddle, which also contains one of your feet, while your hand is resting on a piece of well-earthed ironmongery? Some very high spec earth-leakage detection and cut-off is clearly called for.
"..The connector itself *is being constructed* by German firm Mennekes,..."
"The Mennekes *proposal* has already been agreed upon by ....."
Key question: Who owns the design rights (IP, form and function, appearance, etc., etc) to this simple arrangement of plastic and metal?
Will anyone jump up in 5 years time and say "Hey, we have a patent on that, pay us royalities!" ?
Wasn't there some talk a while back about using inductive chargers?
They would prevent any sort of accidental electrocution if you handled the power end and there could be no spark jump if power was still live when you unplugged it. Meaning you could host them in existing petrol stations with no danger from petrol fumes.
I do hope that the plug present pin is also used to control the switching of the power supply.
If not, it looks like it would be feasible to plug just one end of the cable into a charger, making the plug on the other end become live. Also, if the connector at the car end were accidentally pulled out, a similar situation would arise. It would be very easy for a curious child to stick their fingers into the holes of the plug and get a nasty shock.
On top of that I don't think I would be particularly enthusiastic about handling a live 400V connector in the pouring rain...
@ Richard: Induction is so inefficient you may as well use petrol.
@ Altis: The control pilot is for the data link.
I'm more worried about the whole 3 phase idea though. The plug is rated to 63A, so could, in theory, deliver a maximum of 20KW with a 3 phase source. However that's 2.5 hours to charge a 50KWH battery - so much for fast charge. Oh, and good luck trying to buy a 20 KW 3 phase charger that will cost less than the battery and weigh less than 50KG - Its kind of a dumb idea to have an on board high power charger.
High current (~600A), DC connectors will be the way forward, with a cheap, on board low power over-night charger that wont need anything fancier than yer standard kettle plug.
As has already been stated, it's much better to have a separate low-power sensing system to detect the insertion or removal of the plug, to avoid arcing. Besides which, if there is no power to the charging point for some reason then you haven't got "the entire EU electric grid" at your disposal to detect if you're plugged in or not.
The earth pin will connect first/disconnect last for safety. I imagine this connects to the plug present pin so that the car can detect when the plug is inserted, independently of the state of the charging point. The data pin looks to be recessed further than the power pins, so that it can be used to detect when the plug is inserted properly, allowing power to be applied after the main contacts make and removed before they break, thus avoiding arcing.
Altis: there IS a data connection! One pin (with return via the earth pin) is enough to have a bi-directional conversation of any level of complexity.
[@ American Plug Digger] Nope. American cars will continue to use gasoline, which will plunge in price once all the Europeans have gone over to cute li'l electric golf cart cars so that once again we'll be able to drive our cast-iron bowling-alley-sized Chrysler Le Behemoths from New York to Chicago in first gear for about eight cents.
We've also figured out that that whole "ozone layer hole" thing happens over someone else's country so it's their problem, not ours. Bonus!
Thrrrp! :oP
Did you not read the last line... here it is again more succinctly:
if the flap is open the car won't go!
and wtf is wrong with the existing standard connectors?? oh yeah you cant meter&tax the outlet...
any smart meter could check for connection before ramping up the juice...likewise auto disconnecting the power when the connection's resistance increases or connection is severed. ie as the plug is drawn from the socket, the conductor area decreases increasing the resistance and tripping the power.
Anyway there are even ways to measure the capacitance of a cable even with no connection at the other end.. you dont need an extra pin for the job, but as I have suggested theres already a much simpler way.
Why does it actually need the "plug present" pin ?
If there's no data on the control pin, then it's obviously not plugged in.
An "open-circuit" on the control pin could immediately signal nothing plugged in.
The control data could also contain a secure data stream interchange that only allows the electricity to be supplied if the vehcile user is correctly authorised.
- Steve
back side of car makes design sense for a few reasons:
... it might be closer to the charging convertor and batteries , it's not the electric motor that's being charged. ( besides your assumption that the motor(s) would be in front, rather than within the drive wheels)
... putting items in the front of a vehicle, like a door / flap has a greater potencial for aerodynamic drag than on the back side
... this rather critical part , that if mangled might create a short, is less likely to be damaged on the rear side in the most common accidents
... from a design / ergonomics viewpoint , it's probably best to put the *fuel* input in a familiar location at a comfortable height
even at 400v 3phase, it's still TOO LONG to charge. We need a 300+ amp 4 phase connection, if not more, at 440v. Li-Ti and Li-Su batteries are capable of charging to 85+% capacity inside 10 minutes, given sufficient power sources. We won't get that kind of power in our houses, but at home you can live with a 2+ hour charge cycle, but on the run, charging in 10 minutes will be much prefered, so we would like a power connector that handles 220v 30amps, 440v 3 phase 60 amp, and high voltage high amp 4 phase, all in 1 connector please....
And the plug plugs the tax hole!
@Francois 21st May 2009 11:46 GMT: "...and poof ! Electricity-for-the-car can be taxed as much as you'd like!"
Such vitriol for something that is not new... or haven't you noticed the different power tariffs on your power bill? (hot-water tariff, standard tariff, after-hour tariff, etc, etc...)
Daniel Bennett: This might be complete rubbish, so I hope someone corrects me if I'm wrong, but I think the problem with charging from the movement of the wheels is that you need some charging wires to touch the drive shaft, which creates drag (i.e. reduces the efficiency). On a petrol car, this doesn't matter because the waste of petrol is considered to be a small loss relative to charging the battery, but on an electric car I'm sure you'd use more electricity than you'd gain. There's no such thing as a free lunch.
Herby: Magnetic connectors are a last resort - you've still got a chance of damaging the connector or (more likely) the cable. Far better to just stop the car from moving.
A magnetic connector has other disadvantages too - it tends to grab any USB cable that your fumbling to plug in without looking carefully. When scaled up to the size required for a car charger, I suspect it would be pretty good at grabbing keys...
Daniel Bennett,
Excellent idea, otherwise known as a perpetual motion machine. It's never been done successfully before, so be sure to apply for a patent. You'll need a thick skin for that.
Seriously though, it should be possible to recoup SOME energy when braking or going downhill (and that is happening with KERS in Formula 1). But whether it's worthwhile would depend on the weight and size tradeoff.
Clearly the people designing this are idiots because they missed one of the most obvious points - one end should be male and the other female. When I run out of gas... er... electricity - while pulling into my drive I need to run to all the neighbors and collect their cables, then chain them together to reach my vehicle stalled out in the street.
You mean like the Toyota Prius, Honda Insight, MINI-e (etc. etc.) already do right now with regenerative braking?
Yes, it is worth the effort, as any Prius driver who's idly watched the status display as they coast to a halt will attest. It's sort of how the hybrid and pure 'leccy vehicles get the bang for their buck you know and not a new idea at all.
As for magnetic plugs, given the recently documented habit of said Apple connectors to short out when the lead's tugged, I'm not sure that applying this tech to 400v connections is a good idea....
Why re-invent the Wheel?
I was interested by your article on the design of a standard plug for connecting e-cars to the mains for charging.
We manufacture under license in U.K. the Auto-Eject which is a shoreline connection system. We have sold 10,500+ in U.K. & Ireland and it sells around 20,000 units p.a. in U.S.A.
As it Auto-Ejects it negates the need for a drive-disabling system, and is used in conjunction with the Auto-Safe switch on the wall or post which gives an immediate dead cable when ejection happens.
It is simple and uses standard 3 core flex.
Highly reliable and very available, it is a long established system that really works very well indeed. In UK it is fitted to nearly all NHS A&E ambulances, large numbers of fire engines and police vehicles, as well as M.O.D. and other vehicles.
We make 3 versions, available at 110 volts, 230 volts and 400 volts, in 15 and 32 amp connector sizes.
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