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Thursday, January 11, 2007

Powering GM's Electric Vehicles

Recent advances in battery chemistry and systems design could lead to working prototypes by year's end.

By Kevin Bullis
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A123 Systems has designed a new automotive-grade battery that may make General Motors’ plug-in hybrids possible.
Credit: A123Systems

General Motors (GM) recently announced that it is developing two types of plug-in hybrid vehicles, cars designed to run exclusively or almost exclusively on electricity for daily commutes. (See "GM's New Electric Vehicle" and "GM's Plug-In Hybrid.") But the announcements came with this caveat: the battery technology isn't ready, and production will have to wait. In reality, the battery technology is actually quite close to being ready.

Indeed, GM's vehicle chief engineer, Nick Zielenski, says that individual batteries are already good enough. "We've got enough data at the cell level to feel that the technology is there," he says. What remains to be done is packaging the cells into large battery packs and testing them in actual vehicles. This will be a challenge, Zielenski says, since there is a big difference between using "a single cell and multiplying them all together to get the energy levels that we need for this type of vehicle." But according to development contracts GM recently signed with two groups of companies, such battery packs will be ready for testing in vehicles by the end of this year.

Making batteries for vehicles, especially plug-in hybrids, is very challenging. For accelerating and climbing hills, the battery pack has to deliver enough power to supply the electricity demand of several houses at once. The energy storage capacity required to give a vehicle a 40-mile range would be enough to power a laptop in continuous use for weeks. Yet the space on board for such a battery pack is limited. "What we need is a very reliable and long-lived battery that has also got quite high energy density so we can find a place for it in the car," says Peter Savagian, director of hybrid power-train systems at GM.

Developers also need to make packs that can survive extremes in temperature and constant vibrations on the road, and still last the life of a vehicle. And they have to make the batteries safe. Last year millions of laptops were recalled because of the danger of their batteries bursting into flame. A plug-in hybrid would have the equivalent of hundreds of laptop battery packs bundled together.

Remarkably, at the level of individual cells, many of these problems have already been addressed. Lithium-ion batteries have much higher capacity than the lead acid batteries used in electric cars in the past, and even more than the nickel-metal hydride used in hybrids today. According to GM, its new Chevrolet Volt concept vehicle stores the same amount of energy as the company's EV-1 electric vehicle, but in just one-third the area. And while lead acid battery packs have to be replaced every couple of years, new lithium-ion batteries seem from lab tests to be able to last 10 years or more.

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Comments

  • Totally Cool!
    SVE on 01/11/2007 at 10:02 AM
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    This will likely spur superior alternatives to oil, and stifle prospects for cellulosic methanol and fuelcells. It can also benefit from green-renewable electricity.
    Rate this comment: 12345
    • Re: Totally Cool!
      john.pujol on 01/11/2007 at 12:30 PM
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      The Volt will still use gasoline to recharge its battery, so biofuel isn't  entirely out of the picture.
      Rate this comment: 12345
      • Re: Totally Cool!
        hamid on 01/15/2007 at 12:25 AM
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        No, the Volt uses a wall outlet in your garage to charge the battery.  Rarely does it have to start its engine.  You can also buy a larger battery pack for the Volt, and essentially never use the combustion engine.
        Rate this comment: 12345
    • Re: Totally Cool!
      grumman581 on 01/11/2007 at 6:48 PM
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      If the technology was actually mature and the economies of scale would decrease the price, we would have that sort of battery in our cars already instead of the lead-acid batteries that we are currently using.  Let's just say I'm a bit skeptical of their claims.  Electrical vehicles have potential -- ON GOLF COURSES.  I don't see them replacing internal combustion powered vehicles anytime soon.  The hybrids might have a bit of potential though.  Trains have used diesel electric for propulsion for quite awhile, although for different reasons.  Ramp up biodiesel production and either go with straight diesel engines or a diesel electric hybrid instead of mixing ethanol with gasoline.  Ethanol should not be in gasoline -- it should be in drinks!
      Rate this comment: 12345
      • Re: Totally Cool!
        Elroch on 01/11/2007 at 8:46 PM
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        Bah, humbug. These new fangled internal combustion engines may have novelty value but they'll never replace the horse and cart.
        Rate this comment: 12345
      • Re: Totally Cool!
        Paul Scott on 01/11/2007 at 9:31 PM
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        Grumman581 suggests that EVs are better suited for golf carts and not cars. I drive a Toyota RAV4 EV designed in the mid-90s to run on Nickel Metal Hydride (NiMH) batteries. The 95 Ah pack in my RAV holds 27 kWh and allows me to travel in excess of 120 miles. The LiIon batteries from A123 or Johnson Controlls/SAFT have a significantly higher energy density than NiMH, and according to the GM engineers, these batteries are meeting the cycle and calendar life requirements for the Volt.

        BTW, my car serves virtually all of my driving needs, well over 95%, and my 3 kW PV system provides me all the power I need to run my house and car for the whole year. My electric bill last year was $48.95. None of my money went to the oil companies or the Saudis. You can't do that driving a Prius.

        There are hundreds of these cars still on the roads 5-6 years after manufacture and many with over 100,000 miles on the odometer. Virtually no degredation of the battery pack so far. And virtually no maintenence has been required.
        Rate this comment: 12345
        • Re: Totally Cool!
          grumman581 on 01/12/2007 at 4:38 PM
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          Maybe where you're at, 120 miles for driving for a day will work, but there are those of us who prefer to not live in the inner city and as such, our commutes plus other errands could definitely push past 120 miles in a day.  Not being able to quickly refill whatever type of energy storage device that you're using is a significant disadvantage for us.  People don't want to have one car for just commuting around the neighborhood and yet another car for longer trips.  Most families have at most one vehicle per licensed driver.  Many only have a single vehicle shared among all the drivers.  Until an electrically powered vehicle can do everything that an internal combustion powered one can do, they're not going to get mainstream acceptance.  Regardless, I stand by my previous statement -- ethanol should be in drinks, not fuel.
          Rate this comment: 12345
      • Re: Totally Cool!
        asdar on 01/12/2007 at 8:56 AM
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        It would be very nice if economies of scale could fix all our problems. The process of making batteries isn't so straight forward as welding two pieces together.

        I'd love to take the Tesla roadster out on a golf course. 0-60 in 4 seconds, you could race the ball to the green. At a 250 mile range you could probably make quite a few rounds in no time.

        If they made this car to the specs they have now they could fit a firefly lead acid battery in there and people would buy it. If they can get something like the quick charging Altair or A123 in for a reasonable price this car is selling now even if the range is 20 miles.

        50 mpg with a 20 mile pure electric range is still better for most comuters than the prius hybrid at 60 mpg which sold very well.
        Rate this comment: 12345
        • Re: Totally Cool!
          grumman581 on 01/12/2007 at 4:47 PM
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          Maybe where you're at a 20 mile range will actually do something, but around here, a 20 miles range won't even get you all the way *to* work, much less back home afterwards.

          If I want to save gas, I ride my sportbike... If I need utility, I drive my Dodge QuadCab 4x4 pickup...  If I'm going somewhere that has small parking spots or I'm going out in the woods, I drive my Jeep.  Each vehicle has a different mission profile.  Most people don't have the luxury of being able to do this though.  They have to try to find one vehicle that ends up being a compromise to their different mission profiles.
          Rate this comment: 12345
          • Re: Totally Cool!
            asdar on 01/17/2007 at 12:17 PM
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            The number that the Volt gives for commuters with less than a 40 mile round trip commute is 76%.

            Just because a new technology won't hit your demographic doesn't mean it's useless.

            I live in an apartment for the moment so I won't be able to plug in. I wouldn't say that plug in's are a waste because I can't use them.
            Rate this comment: 12345
      • Re: Totally Cool!
        gabrielg01 on 01/12/2007 at 12:15 PM
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        Grumman dear, you know GM already had a working electric vehicle, which they killed. There is also Tesla and several other small companies, making real electric vehicles - so this technology is mature enough to be used in more than golf carts. Wtf? You are working for the oil industry?
        Rate this comment: 12345
        • Re: Totally Cool!
          grumman581 on 01/12/2007 at 5:04 PM
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          Although I have worked in the energy sector over the years, this is not uncommon for someone like me who is in the Houston area.  Quite frankly, I just do not see them replacing internal combustion engines anytime soon for other than a small minority of individuals who are willing to live with the compromises with respect to range and such.  I'll admit that they definitely have potential considering the amount of torque that you can get out of the motors, but until they can be quickly recharged (i.e. no more time than it currently takes to fill up your car), I suspect that they'll remain a niche market.  Hybrid type vehicles that run on electricity from the batteries but have a small diesel engine that recharges the batteries continuously or as needed might be enough to gain acceptance.  I recently finished a trip where I drove 700 miles the first day and a bit over 1000 miles the second day.  As far as I know, no current non-hybrid electrical vehicles would have been able to complete that particular mission profile.
          Rate this comment: 12345
          • Re: Totally Cool!
            jstack6 on 02/22/2007 at 5:41 PM
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            The altairnano lithium batteries to be used by Phoenixmotorcars could handle that trip. They can recharge in about 5 minutes if you have the large high power charging stations. This would add to the peak power demands so it would be best if you charge at night off peak while you sleep.
            Until then a hybrid would have to cover travels like that. Or a VLJ light jet could be the best choice. Very efficient and save time. 
            Rate this comment: 12345
    • Re: Totally Cool!
      ricmauricio on 02/06/2007 at 4:10 PM
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      All of you guys seem to be scientific types (whereas I am a business type); but I wonder why with the advancements in solar cell efficiency and battery technology, why we can't couple the two and install solar panels into the roof of vehicles to charge the battery. I know my roof gets very hot even on overcast days.

      Ric
      Rate this comment: 12345
      • Re: Totally Cool!
        roboclaw on 07/09/2007 at 8:54 AM
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        Thats already being done and according to some articles Toyota is thinking making it standard in future Priuses. Problem expense every little thing you add also increases price and there is a limit to what people will pay "upfront" even if it saves them money in the long ron. Wait to wafer thing cheap printed solar cells come on line in the next year or two and watch power generation change forever.
        Rate this comment: 12345
      • Re: Totally Cool!
        cretin001 on 10/05/2007 at 5:03 PM
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        i on the other other hand seem to be the stil in high school type
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  • Chip
    john.pujol on 01/11/2007 at 12:28 PM
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    What sort of device controlls the battery's power output? who makes it?
    Rate this comment: 12345
  • Recycling and Regen Braking
    RickMerrill on 01/12/2007 at 10:52 AM
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    Of the cost of replacing Prius batteries I estimate about 40% is for recycling the materials.  The ability to recycle must be built in, especially for rechargable batteries, whose contents are often toxic.

    The batteries also need to be able to take a charge quickly if they are to be used in regenerative braking, which the Prius has (do others?). 

    Rick
    Merrill
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    • Re: Recycling and Regen Braking
      gabrielg01 on 01/12/2007 at 12:09 PM
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      I think we could use a mixed battery set. A slow charging/discharging set that would power the vehicle for long cruises. And then, a fast charging/discharging set that could be used to give extra power during acceleration or climbing hills. This latter set would also absorb the power from regenerative braking.
      Rate this comment: 12345
    • Re: Recycling and Regen Braking
      DrWelly on 01/12/2007 at 4:09 PM
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      Battery vs SuperCap ... that's what is really asked here.

      For EV and Plug-in, the battery is large enough that it can easily absorbing the Regen power/energy, which is however very different from fast-charging capability.  A 40 or 80Ah battery pack can be recharged by the Regen current, typically, at 100-150A, that's merely 2 or 3 C-rates.  Any laptop computer battery can do that trick as long as it is not being charged near to the full charge state.  That is also why Tesla can work with existing Li-Ion technology.

      However, for HEV, the battery must be capable to accept 10 to 20C-rate pulse charge current during Regen because the battery is only 3 to 5Ah.  That is the REAL fast-charging capability.  There is only a handful of new battery technology such as A123, Altairnano, to name a few, would work under these conditions.  That is also why we constantly flipping back and forth on arguing whether the battery technology is ready or not.  It all depends on the applications and how politics is played.

      To parallel two set of batteries for high and low-rate operations is similar to the SuperCap architecture for which the SuperCap is there to buffer the high current pulse, the difference is the design is to recharge the SuperCap with the "low-power" battery as it depleted and recover the SuperCap energy by slowly recharging the battery after Regen event.
      Rate this comment: 12345
    • Re: Recycling and Regen Braking
      hamid on 01/15/2007 at 12:40 AM
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      The A123 nano-phosphate li-ion batteries can recharge to 80% capacity in 5 minutes, 90% in 10 minutes.  This is faster than filling your gas tank with gasoline.  In future electric filling stations, the vehicle will communicate your financial charge card info to the pump, saving you another couple of minutes.

      The nano-phosphate li-ion batteries can be disposed of in the city dump.  They contain nothing toxic.  But they do have a recycle value as well.
      Rate this comment: 12345
      • Re: Recycling and Regen Braking
        DrWelly on 01/17/2007 at 1:45 PM
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        The 5-minute charge capability is great and nice marketing tool, but it is not practical.  I doubt that EV will ever be fully recharged in a charge station the same way that we are today filling the tank in the gas station. 

        Let's do the math.  A 5-minute recharge to 80% SOC implies a maximum charge current of 9.6C-rate (=0.8*(60/5)).  A typical EV pack needs 50Ah at the minimum for a reasonable driving range, and thus a charge current will be about 480 Amps to recharge in 5 minutes.  Even though the advanced battery can handle that kind of charge current, can you imagine the size of connectors and cables that it will require to pass that kind of current.  Also, the nominal voltage of a EV battery pack is about 300+ Volts, it will require a charge station that is capable of output of minimum 200kW.  The USABC target was in fact 40kWh pack (higher voltage or larger capacity), that means the real charge system will actually need to be 400-450kW output in order to return 80% energy in 5 minutes.  And perhaps double the charge current!!

        So, charging from the wall overnight is probably the most practical and reasonable solution for any forseeable future EV ... More likely, we will boost the battery at the station to get enough juice for the trip home, and then plug it in.
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  • oil dollars down electric bills way up
    urian1975 on 01/12/2007 at 1:09 PM
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    If we put these kinds of vehicles in every home it would billions of dollars for the electric companies to build new generation which would cause electric rates to go up. power companies are having a hard enough time keeping up supply do to the growing population.
    Rate this comment: 12345
    • Re: oil dollars down electric bills way up
      EVangel on 01/12/2007 at 3:40 PM
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      I guess urian didn't read last month's Pacific Northwest National Lab report showing that 100 million electric vehicles (EVs) can be recharged overnight without building one more power plant.
      http://www.pnl.gov/news/release.asp?id=204
      $25 more on the electric bill and $150 less for gas monthly; EVs save money for their drivers!.
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  • Put photovoltaic cells on the surface of the cars
    gabrielg01 on 01/12/2007 at 8:22 PM
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    One could also incorporate photovoltaic cells into the body of the car. In southern states with lots of sunshine, just parking the car at work could give a considerable charge to the batteries.

    Check this dude out; he put cells onto his electric scooter. Pretty cool!
    http://www.builditsolar.com/Projects/PV/pvscooter.htm

    And speaking of electric commuter scooters, there will be commercial ones pretty soon. Here is the Vectrix:
    http://www.vectrix.com/default.aspx?portal=1&page=1

    and the specs for the electric version are here:
    http://www.vectrix.com/default.aspx?portal=1&page=16

    Within 20 years the oil industry will be dead.
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  • Battery swapping stations instead of gas stations
    gabrielg01 on 01/12/2007 at 9:19 PM
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    The naysayers also bring up the issue of range against the electric cars. But this is not that big of a problem as they want you to believe.

    It could be easily solved by a standardized battery design, and a standardized battery docking compartment across vehicles. Then we'd just have to convert our gas stations into battery swapping stations. The driver would get a fully charged battery in exchange for the discharged one. One would pay for the electricity used for charging. The swap would be performed by technicians, but it should not take longer than a regular gasoline fill-up.

    The vehicles could have two big battery packs. First, one battery pack would be run down, and the 2nd pack would work as the backup. The driver would be notified that there is only one pack left, so he/she needs to head to a "gas" station for the swap. After the run-down battery is swapped for a new one, the vehicle would still run on the 2nd battery, and this time the newly swapped battery would function as the backup. So on and so forth...one could do this forever, never running out of "juice". And with all the "gas" stations around, range would never be an issue.

    Why are we still relying on dirty oil?
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    • Re: Battery swapping stations instead of gas stations
      dsuprina on 01/12/2007 at 11:15 PM
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      The A123 cells have very fast recharge times.  If supplied sufficient amps so as to support the recharge of multiple cell banks in parallel, we may be talking “fill-up” times comparable to that of a gasoline SUV… which means that current gas stations, which are already on the grid, could be retrofitted to provide quick recharging.  Of course one would still elect to do a slow recharge over night so as to properly equalize the cells on an occasional basis.  So now I just have to get the family Dodge Caravan to last another year or so until GM is ready…  (Fingers crossed)
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    • Re: Battery swapping stations instead of gas stations
      hamid on 01/15/2007 at 12:44 AM
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      The A123 nLiFePO4 (nano-phosphate) batteries charge to 80% in 5 minutes, 90% in 10 minutes.  5000 charge/discharge cycle life.  That is 500,000 miles of life at least.
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  • Tesla Motors has solved the problem?
    snedunuri on 01/14/2007 at 3:33 PM
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    All of you such as Gruman grumbling about the limited range or impulse of EV's check out Tesla Motors' web site
    http://www.teslamotors.com/index.php?js_enabled=1
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  • Lithium Metal Polymer
    buckydome on 01/16/2007 at 2:11 AM
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    I am only a member of general public,and do not always understand the technology subtilities concerning Lithium batteries as developed for use in electric cars,  but as I am interested in electric cars I am following the work of the BATSCAP company (part of the  BOLLORE group)here in France on the Lithium Metal Polymer battery (http://www.batscap.com/la-batterie-lithium-metal-polymere/) technology targeted for electric car use. This Lithium Metal Polymer technology seems to be a little different from others mentioned, with less problems concerning overheating, and more power to mass ratio. I have found little or no comments on this particular project on different 'energy' information sources (like yours) on the net. Any comments?
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