Bigger Batteries Key To Better Quick Charging For Electric Cars

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Eaton CHAdeMO DC quick charging station, Mitsubishi headquarters, Cypress, CA

Eaton CHAdeMO DC quick charging station, Mitsubishi headquarters, Cypress, CA

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To help make electric cars more palatable for long-distance driving, the 2012 Nissan Leaf SL and 2012 Mitsubishi i can be rapid-charged from empty to 80 percent full in around 30 minutes using specially-designed Chademo rapid charge stations. 

For those using them, rapid charge stations provide a welcome alternative to slower, level 2 charging stations, but require up to 50 kilowatts of instantaneous power from the electrical grid in order to work, leading some to worry about the strain that they place on the electrical grid.

The solution, developed and deployed in Chicago by electric car infrastructure firm 350Green, AllCell Technologies and the Illinois Institute of Technology, is to power the charging stations from big battery packs.

As part of a smart-grid pilot project, the large-capacity battery packs slowly charge from the electricity grid when demand is low.  

Fast Charging 2011 Nissan Leaf

Fast Charging 2011 Nissan Leaf

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When grid demand is high, the packs can then feed power back to the grid as required, also providing the necessary power needed to operate a rapid charging station. 

By combining storage and charging capabilities, the project aims to develop a solution that does not negatively impact the electrical grid.

But by charging up the large storage batteries at night-time when electricity is plentiful, it could also lower the cost of rapid charging. 


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Comments (11)
  1. "But by charging up the large storage batteries at night-time when electricity is plentiful, it could also lower the cost of rapid charging. "
    Faulty logic. Those storage batteries will cost A LOT and will not last beyond a few thousand recharges before needing replacement. This will HEAVILY impact the cost of charging and drive it up, up , up. UNLESS... those WSU batteries come along
    (as they claim) within the next 12 months. They will cost money
    (but only a third as much or less) but will last a very long time. Overall, additional grid capacity is a much more cost effective solution. It will be quite a while before EVs put much strain on the grid - people won't just throw away their $40K gas powered vehicles - no reason to

  2. I disagree Kent. When calculating demand charges and off-peak electrical rates, the cost of the battery is off-set. The large battery should also be comprised of modules that can be replaced as needed as opposed to replacing the emtire battery pack at once. Storage batteries for DC fast chargers is an excellent idea.

  3. what about using the "depleted" Leaf battery packs. they are said to be replaceable when they reach 70% capacity. so put 6-12 in there and charge them at the highest rate that is available without issues to the grid which i would guess means that they would be full in the morning and hopefully able to keep up with charging demands during the day. this allows them to cycle much more than a few thousand cycles since they can still be utilized at a much lower SOC since there is no weight issues. storage might be a problem but looking at the size of the packs, you could store quite a few in a small space and provide ventilation

  4. After thinking about this .. in the future all EV world, I predict
    that, since the vast bulk of public charging will occur on the interstates, which means the gas (charging) stations located along those routes do not have the electrical capacity, special charging grids will be created by utilities to service only those
    customers. Here is the perfect situation for SMR, small modular reactors of 300 or less MW capacity. One such SMR could charge each of 45,000 EVs with 80 kWhrs during each 12 hour period. SMRs, unlike baseload reactors, can ramp up and down at will. SMRs can produce emission free power cheaply. If I were head of Dom Resources, I would be planning right now for the I95 corridor.We have all the refueling data we need already.

  5. In California, a major hurdle for use of DC fast chargers is the expensive 'demand charge' that is triggered when a DC fast charger is at maximum power. Demand charges go into the thousands of dollars. The solution right now is to reduce the draw of power by adjusting the DC faster charger like the Eaton unit pictured in the article (thank you Mitsubishi 'i'). However, the charge time takes longer. With a large battery pack, the DC faster charger could be used at full power when drawing from the battery pack avoiding demand charges from the utility.

  6. The large grid storage batteries are probably really inexpensive -- they do not have to be lightweight or compact. At MIT they have a liquid metal grid storage battery nearly ready to go:


  7. ...or you use discarded EV batteries with still 60-70% of their original capacity left. Of course it will take a couple of years before those become available.

  8. For EVs ever to become practical for longer distances they need to have 80-100KWH batteries that can pick up a 50KWH charge (~150miles) in under 15 minutes. That will take a 200KWH charger. If 350green is correct that even a 50KWH charger is already a burden for the grid those grid energy storage systems may be the right way to go.

  9. Isn't the biggest limitation of these systems, back to back charging? Sure you can slow charge over night, but what if you need to DC fast charge four LEAFs in a row? Will the unit run out of charge and revert to slow charging?

  10. John, I just read this article on Scientific American about what A123 is coming out with in the spring. You may want to read the article: They said this lithium-ion-battery will only cost $250.00.

  11. @James: From your friendly moderator, a reminder that if you copy and paste comments into multiple articles, they are flagged as spam by our moderation system. Please refrain from doing so. The comment above has been disabled from the other article you posted it on.

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