How can we "refuel" electric vehicles today and tomorrow?
by Sam Abuelsamid on Sep 17th 2009 at 2:57PM 
Renault Zero Emission line-up - Click for high-res image gallery
Among the many claimed advantages of electric vehicles are the ability to "refuel" your vehicles at home, never visiting a gas station again. In principle, the only thing you need to "fuel" an EV is a working plug. However, in life, few things ever turn out to be as simple as they might appear on the surface. For example think about your cell phone. If, like most of us here at ABG, you have had multiple different phones over the years, you have of course noted that every one of them seems to have a different and unique charging adapter along with a completely different battery. In a small hand-held, pocketable device like a phone, it would seem that standardizing batteries and chargers would be a relatively simple thing to do and yet it has only been relatively recently that most phones have begun converging on mini-USB connector standard. Batteries, of course, are an entirely different matter. Now imagine expanding these problems by several orders of magnitude and applying electrification to a car. Cars live in a greater variety of environments and are expected to last a lot longer than the typical consumer electronics device (do you still have your phone from six years ago?). Read on after the jump to learn more about how the problem of charging is being addressed.
The first and most important element is the charging plug. Most EVs of the recent past, including most home-built conversions, have utilized standard household plugs. While this may seem an easy solution, it is actually quite complex. Most conversions are designed to charge at 110V, which is fine for cars that have limited capacity and lead acid batteries. As lithium batteries with higher capacities become more prevalent, they will need faster charging. As MINI E drivers learned earlier this year, 110V just isn't going to cut it.
All this means we need a charging solution that can handle 220V or more. There are multiple types of standard 220V plugs for devices like dryers, stoves, etc. None of these are designed for high numbers of insertion cycles. We've all experienced 110V devices like vacuum cleaners where the pins get bent and sockets get loose over time. This is not acceptable on a car where the car will typically be plugged and unplugged daily and often several times a day. The plug has to be able to withstand thousands of insertion cycles. Given that cars have to operate everywhere from deserts to extreme winter and jungles, environmental sealing is critical as well.
When GM built the EV1 in the 1990s it tried to address these issues by using a paddle with induction charging capability. For reasons that we will get to shortly, that approach is not being used for the new era of EVs. Instead, automakers have collaborated with suppliers through a Society of Automotive Engineers task force to produce a common connector under the J1772 standard (above).
This plug is designed to withstand at least 10,000 insertions/removals with seals that survive the life of the car. It also supports single phase charging at up to 240 V and 70 A. Perhaps most importantly, it also has support for vehicle to infrastructure communications. This is something that no previous connectors, including the EV1 paddle, supported.
Since affordable electric vehicles will have limited operating ranges for the foreseeable future, they are seen as being most useful in urban environments. The problem is that many people who live in urban environments don't necessarily have garages to park and plug in to. For that reason, many local governments – e.g., London, Santa Monica– are looking at building or already have built networks of curb-side charging stations. While cities can afford to offer some free charging today to EV drivers because they are few and far between, this situation won't continue. If EVs become prevalent, drivers will have to pay for electricity.
That's where the communication link comes into play. The comms link will allow the car to identify itself to the charger/grid so that the driver can be billed. Some companies, like Coulomb Technologies, are working on networks of charging stations and plan to offer subscription plans similar to mobile phone service to pay for charging. The communications system will facilitate this. Even when people are charging at home, the link will allow future smart meters to manage when a car is being charged so that drivers can get the lowest cost during off peak hours. Most of the major automakers have committed to using the J1772 connector for charging (More info: how GM will use J1772 with the Chevy Volt). One thing these connectors don't support is 480 V charging. This higher voltage system is being proposed for quick charges with some types of batteries. To support this Nissan will actually equip its upcoming LEAF EV with two connectors, the J1772 and second one for 480V charging. However, before anyone can use this, special quick charge stations will have to be installed at places like businesses and, perhaps, existing gas stations.
The final possibility for the near- to mid-term is battery swapping. There are a variety of problems with this idea that will limit its utility any time soon. First is one of the same issues facing phones: proprietary battery packs. Because battery packs for cars are so large, automakers have to work hard to package them in a vehicle to limit intrusion on passenger space. They are often being incorporated into the structure of the car, making swapping them impossible. Finally, there is the same issue of the connectors that faces charging coupler. The battery connection, is designed for relatively few insertions.
All of these limit the utility of quick battery changing systems. So far, Better Place is the only company proposing such systems and Nissan-Renault is the only automaker that has shown any interest in supporting battery swapping. Other automakers cite the fact that battery technology is still evolving too quickly to commit to standard battery pack form factors along with the previously mentioned issues.
Looking farther out, researchers are still looking at inductive charging as well as mechanisms to recharge vehicles on the go, perhaps from cables or slots embedded in roadways. This however would require huge infrastructure investments and would create many new technical problems. Solar is another possibility, but it wouldn't be useful at night. Even during the day, solar cells don't have enough conversion efficiency to power a car with a panel small enough to fit on a car.
Any way you look at it, it appears we will be living in interesting times in the coming years.
Reader Comments (Page 1 of 2)
kert 3:15PM (9/17/2009)
Somehow this article failed to touch on TEPCO/Mitsubishi/Subaru quick charging solution altogether.
See
http://green.autoblog.com/tag/tepco/
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Mark Kiernan 3:22PM (9/17/2009)
They battery recharge system is much better than that of the battery swap system. This is because the cost of infrastructure of recharges require a tiny footprint - they can put up along the side of the street. Also battery ranges become bigger and bigger so the need to swap become less and less, imagine a battery that can go 1000 miles per charge, some people may not swap it for up to a month.
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PopSmith 5:05PM (9/17/2009)
With battery swapping, customers (and businesses) would have to worry about someone abusing the battery then returning it and abusing the next one they get. This would cause batteries to have shortened ranges, compared to non-abused batteries, and cause anti-battery (or, at the very least anti-swapping) advocates to speak very, very loudly.
If you have the ability to charge a battery in a reasonable time frame from home, work, the mall or where ever you're taking your car (when charging is needed) then most people will take pretty good care of their batteries if that's what is getting them from point A to point B.
Also, as Mark mentioned, batteries ranges are getting larger. At relatively the same time battery sizes are getting smaller. This means the same size battery that is currently 53 kWh will, in the hopefully near future, have a 100+ kWh capacity.
Doug 9:54PM (9/17/2009)
I said this in another post, but I'll repeat it here since it seems relevant:
I don't think battery swaps make a lot of sense at the consumer level. They're certainly possible, but I don't think the relatively small increased utility (since individual consumers would only rarely need this service) is worth the infrastructure costs and the logistical headaches. Probably fast charging or an EREV is more cost effective.
Battery swaps are a reasonable solution for vehicles like buses, taxis, postal trucks, etc. I.e., situations where you have a standardized fleet of vehicles that return to a central location.
skierpage 5:29PM (9/17/2009)
The SAE J1772 committee has "A Level 3 (fast charge) working group has been created, chaired by Dave Francis of AeroVironment" for the higher ~400 voltages. I hope at least the car socket is the same even if the connecting plug and cable has to be beefier. (SAE J1772 is having a web meeting on September 22, Autoblog Green should crash it.)
Battery swap is intriguing and Better Place may be able to find a sweet spot amongst: assuming the cost and durability issues of batteries, reduced EV cost through leasing batteries, tying spare batteries into the smart grid, delivering a fast recharge for 300+ mile trips, etc. But it's so much more complicated than just tossing a few extra battery packs in the trunk at a Charge'N'Go forr a long trip.
Both the J1772 and the European Mennekes plug have an interlock pin to stop the car from running while it's charging. But that would interfere with towing a genset as a range-extender.
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Chris M 6:11PM (9/17/2009)
Any automaker that offers a "range extending trailer" will also have a special connector for it, probably at the rear where the trailer would be attached. The requirements for a removable range extender connection are quite different than for a charge connector, including start and stop signaling for the engine, turn signals, brake lights and backup lights, and of course power transfer.
letstakeawalk 6:16PM (9/17/2009)
LOL at the idea of the millions of idiots who can't drive a regular car properly suddenly forced to deal with towing a trailer anytime they go beyond a standard charge.
How much bigger will future parking spaces have to be in order to accommodate all the people on road trips?
/that's why an ICE range extender like Lotus has proposed makes so much sense
jim 8:12AM (9/18/2009)
440 Volts! Many homes will have difficulty providing 220V, when you consider 1000's of older homes with 100 A service and homes that have maxed out electrical panels.
And yes I know you can have a 220 v line w/100A service, but you'll likely need to decide whether you want to dry clothes or charge the battery and you should hope the refrigerator doesn't kick in.
440V makes sense from a charging perspective but it creates other problems.
Eletruk 6:10PM (9/18/2009)
The 400+ volts is for a quick charge station, not for home use. The idea is that you are NOT at home, that's why you want a quick charge.
Mike Z 5:46PM (9/17/2009)
I think it's really not worth putting too much into charging this early in the game. The whole standard setting process will play itself out in the end. EVs/RE-EVs/PHEVs will demand it so the supply is assured.
What really matters is getting stuff that needs to be worked out is getting something that needs a plug on the market.
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Serge 6:53PM (9/17/2009)
Mike, perhaps battery standardization (a la PBP) is too early at this point, but plug standardization is an absolute must. Standardized interfaces always lead to faster adoption.
Over in Europe, they just finalized a Mennekes plug in May and now every other car at Frankfurt Auto Show displayed is a plug-in. The J1772 standard needs to be finalized yesterday.
Doug 9:03PM (9/17/2009)
I think we should ditch J1772 and just adopt Mennekes over here as well. It seems like a better, more thought out standard.
Sure there are currents/voltages (phases) available over there that aren't common here, but the manufacturers will be selling the same or similar cars in both regions. Seems to me a main purpose of these new connectors was that there should be some 2-way communication so the car and charging station can negotiate the charging conditions anyway.
Joeviocoe 6:01PM (9/17/2009)
For battery swapping concerns of uneven battery usage.
Since battery monitoring technology has come a long way... manufacturers can come up with a metric for analyzing the life reduction of a particular battery pack.
Elaboration:
User A and User B are going on two separate trips with swapped batteries.
Both pay with mandatory credit cards (like renting a car).
A travels farther than B.
A drives normal while B abuses the battery.
B is charged more than A because the computer readout when returning the battery shows the charge/discharge cycles on the road.
The cost can directly reflect how much of the battery's life was lost.
Also, when buyer purchase a used battery pack for swaps, the historical data of the battery usage assigns a "blue book value" depending on the life expectancy due to is use/abuse.
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occ 6:57PM (9/17/2009)
To add to what Joeviocoe said:
IMO, Lithium Ion cells behave very predictably, from new to cycled usage, and probably wont even need to keep track of charge cycles. Voltage levels and miles/charge can predict that the battery will have X miles left before Y% discharge. So a 150 mile range new battery degrades to 100 miles would then be taken out of circulation, all the while, the car allows you to go only 100 miles regardless before it tells you to go plug-in or swap. The user wouldn't know the difference in a 100 mile range EV with old or new battery. (same can be applied to power and aging, just like capacity).
Remember Better Place won't sell you the battery (so EV are affordable), so you don't have to worry about buying new/used or swap, or worry about battery conditions, as long as you always have that 100miles after a full charge or swap. That's the beauty of battery swap: I don't own (or have to buy) the battery, so I don't care. Let BP worry about it, as long as I get my predictable 100 miles for $1 every time!
Eventually, you may want to get off of their plans, and buy an out-of-circulation battery for deep discount. You can still charge in your good'ole garage outlet...but why?
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Chris M 11:12PM (9/17/2009)
You'd charge at a garage outlet because it would be cheaper and more convenient for everyday use than going out of your way to a battery swap joint. Even Project Better Place plans for charging being the most common refill option, with swapping being used only when speedy refill is desired.
jzj 11:07PM (9/17/2009)
It makes sense to have swap stations for the following reasons:
1. The consumer is no longer concerned with battery capital cost, quality, technology, maintenance, or warrantee issues;
2. Swapping is far faster and more convenient than charging (or even getting gas);
3. For those who do not have garages in which to charge overnight, it is a necessity;
4. Swap stations would allow for grid storage;
5. Standardization of batteries allows for competition among battery makers, driving down EV costs;
6. Swapping does away with the need for costly, unmanageable, and resource-intensive public charging.
Indeed, there are no good reasons for OEMs to have car-specific batteries, and basic design issues like size, voltage, connectivity, and BMS communications should now be undergoing global standardization.
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EV-1 5:52AM (9/18/2009)
@jzj :
Grreat Post !
You're not from the USS of A, are you ?
- - - - - - - - - - -
The paranoid notion that one exchanged battery would be found "abused" - - - ( ? )
( just like people would hook up that battery pack to their electric oven, or what ? >>>
the vehicles will of course have built-in limitations of any possible "abuse" ) - - - will, needless to say ( ... ? ... ), be eliminated by warranty. Will the battery pack even be removable at all by the customer ? The swapping station would have a locking utility
(either mecanical or electronical or both) so no customer even would get close to tamper with the battery in any way. And self-diagnosis would indicate any defect battery before ever swapped into a vehicle.
Gah !
I've never seen so much perverted negstive thinking be voiced at one supposedly progressive web-site.
- - - - - - - - -
Thanks again "jzj"
DasBoese 2:50PM (9/18/2009)
There are very good reasons for OEMs to have car-specific batteries.
Most obviously, different types of cars require different batteries, i.e. size, electrical properties and position within the car. Surely a few standard formats could be introduced, but that will make the costs for swapping systems skyrocket, fast, while in the end automakers might still decide that the convenience of swapping is not worth sacrificing the efficiency and handling benefits of an integral battery optimized for the specific car.
Secondly, since weight reduction is essential for EVs, using the battery as a stressed chassis member is a good idea. Aerodnamics are important too, demanding a smooth underbelly which is at odds with a swappable floor-mounted battery. Safety plays a role as well, an integral battery just isn't as suceptible to damage.
Lastly, it looks like the latest developments in battery chemistry and manufacturing may well make swap stations obsolete due to vast improvements in charge times.
jzj 4:31PM (9/18/2009)
@ EV-1:
Thanks for the kind words.
@ DasBoese:
1. Battery KWH need not necessarily effect the physical battery pack size.
2. Electrical properties -- presumably, you mean voltage -- should indeed be standardized and doubtless will be standardized anyway for reasons of safety, connectivity, aftermarket and OEK manufacture of voltage-compatible components. To give a simple example, you don't want everyone to have to manufacture different wire sizes.
3. Position in the car is basically irrelevant to swappability.
4. Battery packs are amost certain to continue to be flat on the bottom -- and if not, a simple covering would provide for flat bottom aerodynamics.
5. While I like integration, I believe battery packs will never be significantly stressed members as there is no advantage to be gained by this that is not better effected by vehicle engineering.
6. There are no present breakthroughs anywhere near even approaching testing let alone product development let alone pilot manufacture let alone mass manufacture. (For example, both silion micro-wire and carbon nanotube concepts have only been tested at the "let's look at one under the microscope" level.) Even if there were true fast-charging, it does not negate any of the arguments I've presented for swap stations and in fact suggest the further difficulties with public charging: can you imagine the grid havoc if a couple dozen people suddenly starting charging at the same time on the left
side of the street, each puling 440V @ 150A? "Pop Goes The Transformer" (sung to the melody of "Pop Goes The Weasel"). (Lastly: have you seen, or tried to pick up, the size of the cable that can carry 440V @ 150A?)
Thanks.
Joeviocoe 6:31PM (9/18/2009)
"1. Battery KWH need not necessarily effect the physical battery pack size. "
Actually, it does! Unless you completely change the chemistry of the pack, Li-ion batteries all have similar KWH/weight and KWH/volume ratios.
"voltage -- should indeed be standardized and doubtless will be standardized anyway for reasons of safety, connectivity, aftermarket and OEK manufacture of voltage-compatible components. To give a simple example, you don't want everyone to have to manufacture different wire sizes."
wrong... small cars and SUV will need different voltages. Just have the standard charge wires made for the highest voltage 440v... That would also make it physically durable.
"3. Position in the car is basically irrelevant to swappability."
not even close... if swapping facilities are going to be able to swap as fast as a gas fillup, then they need to be ALL in the same place so that technicians are not fumbling with different loading equipment. Packs are heavier than people can be expected to lift.
"4. Battery packs are almost certain to continue to be flat on the bottom -- and if not, a simple covering would provide for flat bottom aerodynamics."
True fro the first part... but the second, so now the swapping facility has to deal with the cover too... you will be lucky if can get a swap in 30 minutes, no where near 5 minutes as they intend.
5. *skipped*
6. regarding advancements in charge time... you may have a point, charge times are usually limited somewhat by battery chemistry, so every 5 years you may have an increase which will not move fast enough for the amount of EVs that are coming soon.
But advancements in charging locations/infrastructure WILL make swap stations obsolete much sooner.
No car is driving more often then resting (except for long-haul trucks) which means that as soon as power is brought to garages, streets, and parking lots, even if you are apartment dwelling, you won't need to swap ever. And for long trips, a range-extending trailer is more feasible or a trip to your manufacturer's dealer will swap out your battery in about an hour.
"Lastly: have you seen, or tried to pick up, the size of the cable that can carry 440V @ 150A?" --- that is 66 kw which would charge most packs in 30 minutes... and should never be carried more that a few feet and only in a garage. It still beats carrying 600 lbs of battery instead of just bringing power to where your car sleeps and being done with it. And since it sleeps 8 hours, no heavy cables are needed.