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Transition to higher voltage batteries / DC fast charging

Discussion in 'Charging Standards and Infrastructure' started by n2mb_racing, Sep 10, 2017.

  1. n2mb_racing

    n2mb_racing Member

    Joined:
    Jun 14, 2014
    Messages:
    677
    Location:
    durham, NC
    I've been wondering, how will Tesla (and other manufacturers) transition to higher voltage DC fast charging? I can only see two options:

    1. Change the battery, motor and other car systems to 800V or higher.
    Cons: You lose the ability to DC fast charge at all existing supercharger and Chademo installations that are only designed for up to 400-500V charging. All the chargers must be upgraded.
    Pros: Car internal wiring is easier.

    2. Keep the battery and motor systems at 400V. Use a DPDT contactor to break the pack in half and put it in series for DC fast charging at 800V, parallel for normal operation (400V).
    Pros: You get backwards compatibility with all existing DC faster chargers and the ability to charge even faster at new high voltage stations.
    Cons: added complexity on the car.
     
  2. widodh

    widodh Model S 85kWh

    Joined:
    Jan 23, 2011
    Messages:
    5,204
    Location:
    Middelburg, The Netherlands
    I think they will go for option 2. A bit more complex, but it does allow backwards compatibility.
     
  3. spottyq

    spottyq Member

    Joined:
    May 7, 2015
    Messages:
    250
    Location:
    Belgium
    Even if you choose to go with option 2, you still have to at least make the HVAC able to operate at both 400 and 800V. (You need cooling/heating when charging fast) and probably also the DCDC converter (though you could probably get away with a beefed-up 12V battery.)

    So basically, you have to convert everything HV except the motors…
     

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