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As electric vehicles (EVs) slowly emerge back into the transportation picture after 100 years of semi-hibernation, consumers may be faced with a paradigm quite different from the regular visits to the gas station most are used to. The three leading new options to re-supply our autos with energy are charging at home, battery swap stations and fast charge stations. There are proponents of each method and, though all three could be used, it is possible that one or more might never make it in the real world or that another method might come to the fore. We'll take a look at these three different energy resupply methods and outline some of their strengths as well as weaknesses. Hit the jump for a comparison that includes plenty of pics and video.

The method that should seem most natural is charging at home. Just as we have become accustomed to plugging in our cell phones everyday, the habit of plugging in your car after returning home could easily become second nature. There are likely many benefits to home charging that ought to make this the most popular option and here we'll cover the three "c"s: convenience, cost, and carbon-control.

There's no questioning the convenience of never having to stop by an energy station to "fill up" before heading off on a busy day about town. It eliminates waiting in lines or out of order machinery and gives you the benefit of your vehicle's full range right from your doorstep. The only time involved is the few seconds it takes to plug in and later, unplug, your car and possibly press a button.

If cost is an important consideration, than charging your EV at home is a no-brainer as it cuts out any profit-hungry middlemen. Also, besides giving you the ability to charge at night when most utility rates are lower, future vehicle-to-grid (V2G) technology may allow you to sell some of your stored energy back to the utilities.

Many future owners may be driving EVs in an effort to reduce their carbon footprint and charging at home could give them the opportunity to control the source of the energy that goes into their car. For instance, they may have solar panels on their roof or could, via their utility, opt for energy from renewable sources.

Of course, everything has its drawbacks and one problem with charging at home is that it is not an option available for some city dwellers. Although charging infrastructure is beginning to find its way into cities, it may be awhile until they are available in residential neighborhoods en masse.



Battery swap stations are a concept often associated with Better Place, an EV infrastructure company. The idea is that when your car needs more energy, you can drive your car into a station and, like an automated car wash, your depleted battery is replaced robotically by one that has a full charge. It is thought that the cars that Renault is building to function with the Better Place model will have the ability to have its power supply swapped and the newly announced Tesla Model S is said to also incorporate this concept. Currently, there are some industrial facilities that use battery swapping to replenish the energy stores of electric forklifts.

The main benefit associated with the swapping model is speed. The whole operation could take less than five minutes, pretty much the same amount of time many people spend filling their gas tanks at stations today. Another plus is not having to leave your car or deal with potentially tangled or dirty cords. You could sit in your vehicle while the operation takes place. Hey, maybe you got an email during the drive, right?

Battery swapping has its critics. A couple of drawbacks to consider might be the capitalization costs of building these stations and the batteries that they would have to have in stock. Some critics also point out the possible dangers of electrocution from a malfunctioning robot swap arm. Standardization of battery shape and chemistry is another consideration that gives one pause. Chrysler alone, for instance, may have 3 different battery pack shapes in its upcoming models.



Finally, there are charging stations. Giving drivers the convenience of charging their vehicles when they are away from home, charge stations have already been with us for some time and are now being installed in at a quickening pace. They offer the opportunity of adding range to your vehicle while you are working, eating or shopping. There are a growing number of companies in this field - Coulomb, Elektromotive, and Better Place (again), to name just three - and the competition should see the evolution of increasingly better equipment and electricity sources. Besides single charging points at strategic consumer locations, some companies are also developing plans for stations that offer you other services while you wait, while others are pinning their hopes on facilities with the ability to "fast charge". BYD, for examples, says their 60 mile range-extended vehicle can add 30 miles of range in ten minutes. They have several stations already built and plan on thousands more.

One of the main drawbacks to charge stations is speed. Most charge points available today take much longer to re-energize batteries than it does to fill a gas-powered car's tank. Also, until standardization of connectors becomes fully implemented, EV owners may have to carry an assortment of adapters to be able to plug in to chargers from different suppliers. Fast charging could possibly address the speed issue but that system, too, is not without its detractors. The demands on the grid would require a lot of infrastructure work without some sort of "energy reservoir" in place. Perhaps more importantly, quickly "pouring" electricity into many of the batteries available today may stress the very expensive component and shorten their useful lifetime.

Whatever the method we eventually use to charge our vehicles, it is a welcome break from the smelly dirty world of disease-causing liquid fuel. Please feel free to tell us what you believe to be the benefits of some of the various recharging modes mentioned above in the comments section below.








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    • 1 Second Ago
  • 36 Comments
      • 6 Years Ago
      I will hang a poster about the comparison at EVS24. Just one remark from a practitioner. There is no need for complex charging infrastructure. A vertically hanging plug allows high flexibility for placing the vehicle somewhere in the street. Intelligent plugs may allow access only to registered users at a flat rate, depending on the vehicle. The losses for the utilities by far outweigh the costs for erecting counting plugs. Progress in technology will allow to retrofit step by step.
      Beware of businessmen trying to make a fortune with the wish to shift to cleaner propulsion! Analyse their business models thoroughly!
      • 6 Years Ago
      Sure, modular swappable battery packs make excellent sense. If every car accepts 2 or 4 or 6 of these universal packs then true economies of scale can kick in in their manufacture. Takes the car companies out the battery business.. and your Honda/Sony car will be perfectly happy with any Durcell/Energizer pack just like AA calls in your flashlight. I would expect a fight from the car companies since they all will push their licensed formats to try and reap royalties... govt/industry defined standards my be required..??
      The modular concept also allows scalability even within your own car... only carry around (or lease) 2 packs for your day to day driving, pop in 4 if you're a log commuter and even allow for 6 or 8 packs for the occasional extended highway trek. Only lease extra packs when needed.Smart!
      Still, swapping need only be an option.. it seems to me there is too much range anxiety about these machines. Remember, charging at home will give you a 100% full tank each morning and depending on your pack that gives 100- 200 or more miles, far more than 99% of us drive each day anyway.
      Charge at home solves fully 95% of average charge need.. additional charge at work solves another 3-4% and the last 1-2% the swap or charge stations can address.Cities and Utilities can easily add a couple metered spots per block next to light poles for overnite charges or even corner stores, etc can offer overnight charge parking that turns their previously dead blacktop parking lots into overnite revenue generators.. not an issue.
      The other proposal that makes some sense is adding on-the-fly charging to carpool/hybrid lanes on highways that many states already have. Around town you will virtually never need a charge and if one lane on the highway had a 440 volt commutator groove cut in it where cars could drop their charge shoe into while traveling at 60MPH uninterrupted ala slot car. install these hot-shoe grooves (that have no effect on other vehicles) beginning 10 miles outside of cities since that is the only place needed. Install 3 miles of charging lane with about the same frequency as Rest Stops.. every 40 miles or so. Might make sense
      • 6 Years Ago
      Battery swaps are a great idea for ease, quickness, providing unlimited range, not having to worry about your expensive battery pack going bad, and potentially removing the expensive battery pack from your purchase cost: but, it does not look like it will happen as manufacturers -- even Nissan, who's is half of the Nissan-Renault partnership that is building Better Place its cars in Israel -- are not even considering building vehicles with uniform removeable battery packs (Tesla S excepted).

      Therefore, until we get quick-charge batteries -- based on new breakthroughs, I'll take a WAG and estimate that we will have real 5-minute quick-charge batteries in perhaps 10 years -- we are likely to get our juice mostly from our home chargers. Which is probably fine, because it'll take 10 years or so for EVs to become so mainstream that they will be widely adopted by everyone for all purposes. Until then, they will primarily be second cars (save for those who are really committed but who do not represent the mainstream).

      The thing is, you really don't want EVs to be charging during the day when there is so much other electrical usage. And, you have to recognize that they pull a hell of a lot of power through the local grid: there will come a time when we will see utility transformers popping from all the current being drawn (imagine just a few dozen EVs fast-charging simultaneously, on 480V at 500A: wow). Obviously, with replaceable battery packs, they can both be charged at the optimal time and always be hanging around to serve as valuable electrical power storage for the grid.

      I regret that the powers that be in this field are still dicking around with figuring out plug uniformity standards (which they just established: woopee), when they should -- dare I say it -- look down the road and see the virtue of uniform replaceable battery packs and therefore set standards and mandate/encourage their use.

        • 6 Years Ago
        "Residential users are not built on high-use lines and their transformers, switches, and whatnot are not intended to have so much use all at one time. Think of it this way: a house tends to pull about 10KW. A fast-charge EV can pull 10,000KW. Multiply this by dozens of homes. See the problem?"

        Incredibly idiotic thing to say. People will fast-charge their EVs at FAST CHARGE STATIONS, not their homes. The rest of your claims are equally mind-numbingly dumb.
        • 6 Years Ago
        "And, you have to recognize that they pull a hell of a lot of power through the local grid: there will come a time when we will see utility transformers popping from all the current being drawn (imagine just a few dozen EVs fast-charging simultaneously, on 480V at 500A: wow)"

        Is that it? Vancouver's trolley bus fleet operates at 600 volts and god knows how many amps.

        Maybe you should ask some engineers at the local power utility before you go shooting your mouth off, decrying how the idea will never fly. I'm certain that they have customers that make 240 KW look like a 9v battery. Like shopping malls for example, or very nearly any manufacturer or industrial consumer.

        Just because it sounds like a lot to you and your piddly wall socket, doesn't mean it's infeasible.
        • 6 Years Ago
        Ernie, indeed I have spoken to engineers: they are quite concerned regarding the future of EVs in various non-coordinated low-use environments pulling a tremendous amount of power at the same time. Your trolleys are relatively few, and are on lines constructed with the knowledge that the trolleys will be using them for power. The large users you spoke of are also relatively few and built in areas where their large consumption is accounted for. Residential users are not built on high-use lines and their transformers, switches, and whatnot are not intended to have so much use all at one time. Think of it this way: a house tends to pull about 10KW. A fast-charge EV can pull 10,000KW. Multiply this by dozens of homes. See the problem?

        And on a different note, let's try to be respectful about claims that someone is "shooting their mouth off": perhaps you might have first inquired as to whether I had checked with engineers prior to accusing me of failing to do so.

        Cheers.
        • 6 Years Ago
        Polo,

        First, there will indeed be need for such fast charging at home because the future of a renewable energy grid will depend upon V2G energy storage, and that will require fast in-out charging.

        Second, the statement "the rest of your claims" are unanswerably indistinct.

        Third, I don't understand why people feel it available in message chatting to speak in a manner they would doubtless not use in personal conversation. Must you say "incredibly idiotic" and "mind numbingly dumb"? It does not reflect well upon you.

        Cheers.

        Jason
      • 6 Years Ago
      How does battery swapping work in real world situations? For instance, Memorial Day is coming up. A couple hundred thousand people will go to the beach 150 miles from here for a few days, a three or four day weekend probably. If a significant number of those people had electric vehicles with battery swapping, then there will be demand for thousands of battery swaps when they get there, and another round of swaps to get back home.

      All winter, there was virtually no demand at all for battery swaps at the beach, then suddenly there is demand for 20,000 on Friday, and another 20,000 on Monday.

      So, do you keep 20,000 sets of batteries sitting there at the beach all winter, tying up enormous capital for months while paying financing and storage costs with no return? Or maybe truck in 20,000 battery packs just for the weekend on diesel trucks, with lots of fossil fuel burning, largely negating the advantage of using electric vehicles in the first place? And what about the poor schmucks who are late getting their swap to come home, and find that the service station is all out of charged packs?

      Battery swapping is one of those ideas that sounds great at first, but when you think it through there are a lot of issues to be resolved. It's certainly possible to make it work, but it's no slam dunk.
        • 6 Years Ago
        Would all those "hundred thousand" people all show up at once at the swap station? Not likely, that would be one humongous traffic jam! No, they'd be arriving over several hours or even several days.

        Now, lets assume that the batteries could be recharged in 3 hours, that means the swapped out batteries would be ready to go again in just 3 hours. So that means the swap station would only need enough batteries for the expected peak traffic over a 3 hour period. Assuming that it takes 5 minutes to do the swap, that's a maximum of 36 packs in 3 hours. Well, we could add another swap lane and double that to 72 packs, still not bad.

        Even if we assumed a modular design, so some vehicles might need up to 6 packs, (see my earlier post) that's still only 432 packs maximum! That's considerably less than 20,000
        • 6 Years Ago
        If you assume 3 hours to recharge the pack, and 20,000 cars arrive over a 24 hour period, then you would only need 2500 packs.

        Ok, fair enough. But if I could just plug in the car for 3 hours once I arrive at my hotel or beach house, then I'm not sure why I would need battery swapping anyway.

        I don't know, maybe battery swapping will work, we'll have to wait and see what happens.
      • 6 Years Ago
      Battery swapping will never happen in large quantities, and fast charges will not happen very often either. They will not be needed.

      Right now we have a problem with short range because batteries are heavy and expensive, thus the need to permanently carry a generator with you, an expensive kludge.

      Eventually packs will have enough capacity for 250-500 miles of range and that will kill range anxiety for good.. most of those packs will be slowly recharged overnight as they are used.

      There is a need for a handful of fast recharging stations (20 minutes) along major highways and those will take care completely of the need for long range travel with electric vehicles.
      • 6 Years Ago
      I think for the foreseeable future home charging is the only realistic option. Unless you count series hybrids (EREVs) which carry their charging system with them.

      As others have pointed out, battery swap is just too complicated to happen. These cars are going to be run by computers, and the each system will be optimized for a certain battery type. The technology will (hopefully) also be improving quite quickly. A 2012 model might be designed around a new battery for example. Setting a standard might hinder progress.

      The same could be true of charging stations. Batteries need to be optimized for having a long life or else they become a bigger ecologic problem than what they replace. Each battery will have a certain charging design profile. I don't think the user will be able to change it on the fly.

      Fast charging is a lot farther off than people imagine. The industry is selling it as something both inevitable and right around the corner. I don't think it is. There are a number of problems that will be quite difficult to solve. We're talking about a great deal of current going through temporary connections that are exposed to the elements. Charging batteries quickly will likely damage their lifespan and create a whole lot of heat.
      • 6 Years Ago
      Each of them plays a different but practical role in the life of a battery car. Charging stations or quickcharge stations allow drivers to fill up and go while on the move. Home charging gives the added conveniences of filling up the batteries at home or office. Battery swap involves the replacement of died-out or faulty batteries and the task can be carried out at charging stations or auto depots and dealerships.
      • 6 Years Ago
      i've always thought that battery swaps would be a good idea. my idea is that it would work the way propane tanks work now. you can go and get your tank filled up, or you can simply exchange the tank (or battery) for a full one and just pay the cost of the fuel (or electricity) with a little overhead to the station.

      i think this is the best idea simply because of the ease of such a plan. of course this would only work if cars have generally uniform battery packs, or perhaps different types of packs (similar to AA, AAA, C...)

      of course home recharge stations would be great as a secondary, or even primary source of power, using changing stations only on long journeys or emergency cases.

      I don't like the idea of leasing a battery pack, or project Better Place's pay for however-so-many miles on a plan and whatnot.
        • 6 Years Ago
        Goo, may I point out how many different devices use the same standard AA battery? And for wildly different applications, too. Some may use just one AA, another may use two, or 3, or 4.

        In a similar way various types of EVs could use the same standard battery packs, varying the number of packs from just 1 for a small short range sub-compact up to 6 or more for a very large long range SUV. A rectangular pack design could be installed horizontally for "under-floor" mounting, or installed vertically for "tank" mounting in the trunk or under the hood. Battery swapping wouldn't make economic sense without a considerable degree of standardization.

        Of course, EVs that aren't designed for battery swaps won't use it, and plug-in hybrids won't need it.
        • 6 Years Ago
        Another option is for battery swap stations to work as vending machines offering battery packs from companies that take part in the program.
        • 6 Years Ago
        well i think, in a perfect world there would be some level of uniformity to the batteries per car
        of course not all cars would have the same pack, that would be impossible, but perhaps, an SUV pack, a sport pack, minivan pack, and like regular car or something. the same way nearly EVERY propane tank fits nearly EVERY gas grill, something like that could be plausible if enough companies were in on it
        • 6 Years Ago
        Although battery swapping sounds like a good idea, it is highly impractical. Automakers get their batteries from different sources; they put different size batteries in different size cars. Think of a battery in laptops. Nearly EVERY single new model has it's own battery size. Forcing companies to conform to standardized batteries prevents them from designing better cars. What if one car is designed to have the batteries laid flat under the car instead of a big block in the back (not saying it's practical or realistic), the battery swapping location has to carry EVERY battery type out there, or will have to pick and choose which ones it will carry. Definitely won't work.
      • 6 Years Ago
      I think the biggest problem will be the standardization that will be required. That will certainly nip battery development in the bud. The station expense will be immense. So accommodating a new model that may extend your range thirty percent will not be possible if it requires a different size or shape. A battery for a Think City is NOT going to be the same as one for a Tesla.

      If there are automatic machines that can adjust to several standard sizes and shape, like a coin operated vending machine, the choice is still going to be limited. If you buy a very cool electric car that is not like everyone else's you risk that even if the machine can change it out there may not be an available replacement at that particular station.

      Then there is battery life. How will you feel when your brand new very expensive electric car that just drove 153 miles on its first charge is replaced with a battery so you can return home and it poops out after sixty miles because the cheap a-- corporation that owns the station has decided that 1/3 range is a reasonable choice compared to replacing it. If a battery diagnostic is added to the car design that warns you of the worn out battery I can hear the arguments now with the attendant in the speaker box telling you it is your car that is faulty, not the battery. On second thought, the attendant will be automated too or in India and complaint will not even be an option. Getting your new battery back will not be an option without paying another fee for running the automated machine again or it will not be possible because the machine will not be designed to retrieve your battery from wherever it went. You will never know your range and each battery replacement will be a white knuckle experience when you get a way from the denser urban recharging environment.

      No thanks.
      • 6 Years Ago
      option 4: extended range battery on a trailer for long trips.
      Easier to addon to electric cars without needing the battery & connectors to be standardize. No problems with swaping your good battery for a bad one.

      Rent it when you go on vacation and need the extra juice.
        • 6 Years Ago
        You could do point to point rental ala uhaul. The trailer would be very small(areodynamic) and have its own wheels to handle the extra weight. Towing a small areo pod on flat ground wouldn't add much in terms of power requirements.
        • 6 Years Ago
        Thanks! That's a great idea. I like it better than the gas generator on a trailer idea.
      • 6 Years Ago
      Standardization strikes me as being an all important key to this technological transition. I would think that the charge chords should be no greater than that which could accommodate 240 volts. Any more than that seems to cause more problems than it would solve, especially when taking into account our present grid capacities. The connector heads, specifically, lend themselves to the idea of standardization, for sure.

      Relative to the battery exchange idea, a couple of things. It seems to me that regardless of the type of battery arrays developed by an individual auto manufacturer, the means of connection beg standardization. The battery bay, for each car, can at least initially be built to accommodate whatever may be the largest of battery modules, as per type of car, and the additional space can be filled with a spacer, (or support mechanism) designed to augment the difference.

      Given that last point; Since the "Swap" technology incorporates the idea that the battery is "analogous to the gas,rather than the tank", if car manufacturers desire different size modules for use in their cars, some sort of cost sharing deal could be worked out between them, and "Better Place", for example, whereby a supply of replacement units can be manufactured in advance for positioning at swap sites, and rotated and delivered on a regular basis, as per demand. I think, along these lines, strategically located recharging facilities might be a consideration.

      One last thing. A totally robotic swap is problematic and could be solved by incorporating a human operator to oversee the robots operation. After all, we could always use more jobs, in this equation.
      • 6 Years Ago
      I think fast charge batteries will become a reality and it will take no more time to charge them than it does to fill a car with gas.
      So, I say home charging and re-charge stations are the way to go.
      If people home charge at night they won't be charging them away from home very often.
      And, home charging at night will put much less stress on the grid.
      Battery swapping won't work. You might be swapping your brand new batteries for some older well used batteries.
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