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The electric car and the standard battery

  1. Jun 25, 2009 #1
    in fact, i want to ask, What do prevent the car companies to produce Standard Battery , and all companies use this SB in their cars, where the number of used SB will depend on the car specifications , by this method we can easily go to replace the batteries instead of stop the electric car and recharge the battery which ususally take some hours.
     
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  3. Jun 25, 2009 #2

    mgb_phys

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    Generally the technology isn't mature enough yet.
    Which battery technology would you choose, Lead-Acid, NiMh, Li-ion, Li-polymer?
    Then there is the shape and size, the removable battery pack for a forklift isn't going to be most suitable for a telsa roadster, isn't going to be suitable for a smart car.
    Finaly the size and weight of the current battery technology means that it is a major structural load on the car and so making it removable would make the car more difficult to design and build and so heavier and more expensive.
     
    Last edited: Jun 25, 2009
  4. Jun 25, 2009 #3
    thank you mgb_phys for your explanation , I hope by 2030 we have the technology that help in producing SB.
     
  5. Jun 25, 2009 #4

    mgb_phys

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    Or technology that doesn't need the batteries to be replaced, like supercaps.
     
  6. Jun 25, 2009 #5

    RonL

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    I read about supercaps of several farads, and quite small, how can they transfer large currents or is that the main weakness at this time? (keeping them cool?)
     
  7. Jun 25, 2009 #6

    mgb_phys

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    Supercaps are upto about 5000 Farads, they can transfer huge currents.
    They are mainly used at the moment in hybrids to provide short term power source or sink at higher currents than the batteries can handle.
    With current technology they are expensive and don't have the power density (W/kg) of modern batteries. I wouldn't have thought cooling was a problem since they are very efficient.
     
  8. Jun 25, 2009 #7

    RonL

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    Do you have a quick link for supercaps ?

    This brings out the stupid in me, if generators can generate power at the same rate that motors use power, it seems that the only storage needed is the power needed to accelerate to a given speed.:confused:

    A flywheel to smooth out the pluses of switching, it seems that a 5000 farad cap would store all the needed energy along with the flywheel, to continue at a steady rate.:smile:

    Just yesterday I was thinking how seldom we consider something as simple as flipping a switch for a light or appliance on, and the power from a generator hundreds of miles away is there in nano or micro seconds.
     
  9. Jun 26, 2009 #8

    mgb_phys

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    In a hybrid car the generator is the motor - when you are braking the motor converts the energy into electricity and stores it for later when you need to accelerate.

    In a power grid being unable to store large amounts of electricity is a big problem. At the ad break in super-dance-pop-idol (or whatever) when everybody goes to make a coffee - extra power stations have to kick in to handle the extra load.
     
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