TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

VW decides against active-cooling system for e-Golf lithium battery

Discussion in 'Electric Vehicles' started by RobStark, Mar 31, 2014.

  1. RobStark

    RobStark Active Member

    Joined:
    Jul 2, 2013
    Messages:
    2,918
    Location:
    Los Angeles
    We asked Darryll Harrison, VW US's manager of brand public relations west, for more information, and he told AutoblogGreen that VW engineers discovered through a lot of testing of the Golf Mk6 EV prototypes, that battery performance was not impacted by temperatures when using the right battery chemistry. That chemistry, it turns out, is lithium nickel manganese cobalt oxide (NMC) in cells from Panasonic. These cells had "the lowest self-warming tendency and the lowest memory effect of all cells tested," Harrison said. He added that VW engineers tested the NMC cells in places like Death Valley and Arizona and found they didn't warm very quickly either through operation, charging (including during fast charging) or through high ambient temps. "The need for a cooling system wasn't there," Harrison said. Since the cells work so well, all the e-Golf needs to keep the battery pack at the right operating temperature is an intelligent thermal control (which regulates the amount of energy expended form each of the cells to keep the heat down) and the ability to dissipate what heat is created into the chassis and away from the pack.


    http://green.autoblog.com/2014/03/31/vw-e-golf-will-not-have-active-cooling-system-lithium-battery/
     
  2. Zythryn

    Zythryn MS 70D, MX 90D

    Joined:
    Mar 18, 2009
    Messages:
    1,660
    Location:
    Minnesota
    Interesting.
    However, after Nissan also was so sure about Arizona not needing active temp control and seeing how that worked out...
     
  3. Todd Burch

    Todd Burch Electron Pilot

    Joined:
    Nov 3, 2009
    Messages:
    4,734
    Location:
    Smithfield, VA
    Methinks VW may be making a mistake here...
     
  4. DuncanWatson

    DuncanWatson Member

    Joined:
    Apr 3, 2012
    Messages:
    284
    Location:
    Seattle, WA
    Dear VW, Good luck with that.

    fools
     
  5. Jason S

    Jason S Model S Sig Perf (P85)

    Joined:
    Apr 20, 2012
    Messages:
    1,350
    Location:
    Rocklin, CA
    They are keeping the performance of the car relatively mild as a trade off for leaving out the water cooling.

    Not a car that'll track well. :smile:

    It might have similar performance to an ICE VW Golf instead.
     
  6. AustinPowers

    AustinPowers Total Smeghead

    Joined:
    Jan 27, 2012
    Messages:
    1,117
    Location:
    Frankfurt, Germany
    Which is all that matters really. After all, a Golf is a "positively boring" family hatchback, not a racing car (and don't start about the R32, that's just a novelty item).
     
  7. David99

    David99 Active Member

    Joined:
    Jan 31, 2014
    Messages:
    2,054
    Location:
    Brea, Orange County
    Not every EV is designed to be a Model S competitor. I see so many condescending comments here about other EVs. Yes the Model S is amazing and that's why I bought one, but it doesn't mean that's what everyone wants, let alone can afford. The majority of people just want an affordable car.
     
  8. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,755
    Location:
    Texas
    Then they shouldn't get a VW. Maintenance will eat you alive. Been there, done that, never again.
     
  9. mkjayakumar

    mkjayakumar Active Member

    Joined:
    Aug 18, 2012
    Messages:
    1,736
    Location:
    Plano, TX
    But... but.... EVs have very little maintenance !

    The heat in question is not necessarily internally generated, but the ambient heat. On a hot day the radiant heat feom asphalt will be easily 120F+ and without active cooling the battery back stays at 90 to 120F for close to 3 months a year - this without you even driving the car or driving it mildly.

    That is the issue
     
  10. techmaven

    techmaven Active Member

    Joined:
    Feb 27, 2013
    Messages:
    2,576
    #10 techmaven, Apr 1, 2014
    Last edited: Apr 1, 2014
    I had figured that Volkswagen was going to stay with air cooled. However, Volkswagen's NMC chemistry is not as far along as I had though. The specific energy on a pack level:

    E-Golf battery pack: 24.2 kWh / 317 kg = 76 Wh/kg
    Model S 85kWh pack: 85 kWh / 544 kg = 156 Wh/kg
    (both of these numbers are total nominal capacity, not actual usable capacity)
    ratio is 76 / 156 = 0.49

    At the cell level:
    VW NMC pouch cells: 59 Wh / 1 lb = 130 Wh/kg
    Tesla NCA 18650 cells: 248 Wh/kg
    ratio = 0.52

    I would have thought that they would try to obtain a more competitive specific energy at the pack level by forgoing liquid cooling. However, they don't really make any gains. They aren't even better than Nissan's Leaf specific energy on their older pack.

    As for air cooling, it is quite possible that NMC chemistry would allow them to get away with air cooling and still maintaining a decent lifespan. The problem with Nissan's pack with the separator which they are changing for new packs soon. The problem is how to get to Tesla's specific energy levels without liquid cooling - that challenge may be far more difficult, which means these companies will still have to design liquid cooling systems for a different chemistry in order to compete with Tesla head to head.
     
  11. qwk

    qwk Model S P2681

    Joined:
    Dec 19, 2008
    Messages:
    2,817
    It always amazes me that these companies don't learn from other companies mistakes. Longevity of the battery should be at the top of the importance list since it's the most expensive piece of the car. A fifth grader could figure that out. I guess that VAG employees aren't any smarter than a fifth grader.
     
  12. CalDreamin

    CalDreamin Member

    Joined:
    Jun 12, 2013
    Messages:
    438
    Location:
    SF Bay Area, CA
    Where did you get the 544 kg weight for the Model S 85 battery pack? I thought Road & Track or one of those car mags had it slightly over 600 kg.
     
  13. Krugerrand

    Krugerrand Active Member

    Joined:
    Jul 13, 2012
    Messages:
    4,271
    Location:
    California
    Correction: No EV is designed (currently or near future) to be a Model S competitor. More importantly, there appears to be no EV being designed to compete with the Gen III, which will be an affordable car for many.

    condescend - act in a superior way: to behave toward other people as though they are socially or intellectually inferior


    Let me rewrite that so that it specifically pertains to your comment: act in a superior way: to behave toward other EVs as though they are intellectually and mechanically inferior. I'd say that the perceived condescension is valid based on the fact that the Model S is superior in every way to every other EV, wouldn't you? In which case that should change the tone of negativity socially associated with the word condescend to a more neutral tone of 'that's just a fact'.

    The majority of people don't know what they want because they don't know what's available, they are continually lied to and/or brainwashed about what's available to them, and are otherwise personally inhibited in garnering the information that would let them know what they want (and then demand it from those continually manipulating the market). Once someone has experienced the Model S with an open mind, it becomes apparent to them what they want in a car and the e-Golf as described is not it. People should be offended if VW goes ahead with these plans for not thinking highly enough about their potential customers to make the best product they can to offer the public. We've got enough cheap, substandard, crappy products on the market meant to take money out of our pockets, we don't need another. Tesla has shown the OEMs how it needs to be done, but still they fail to act accordingly.
     
  14. Zythryn

    Zythryn MS 70D, MX 90D

    Joined:
    Mar 18, 2009
    Messages:
    1,660
    Location:
    Minnesota
    Oh I don't know. Their chemistry may allow them to get a very durable battery without liquid cooling.
    I am just saying I am going to wait and see how it works out before even considering one.
     
  15. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

    Joined:
    Jul 12, 2012
    Messages:
    4,502
    Location:
    Maine
    #15 ItsNotAboutTheMoney, Apr 1, 2014
    Last edited: Apr 1, 2014
    There are also power density requirements that depend on battery capacity and target performance.

    This is why the "American" strategy and Tesla's in particular is so good.
    - When you add liquid cooling you can use a less tolerant chemistry.
    - When you have a larger battery, you don't need as high a power density to get the same performance.

    Tesla's strategy makes it easier for the cell manufacturer, which gives them a chemistry cost advantage. On top of that, they also have the biggest volume multiplier in cell capacity purchases.

    Ultimately it would be great to avoid active cooling because it has the lowest potential cost and highest potential efficiency. But Tesla's cost-centered approach allows for significant gains from incremental improvement.
     
  16. qwk

    qwk Model S P2681

    Joined:
    Dec 19, 2008
    Messages:
    2,817
    Li-ion batteries dislike heat. In the summer, the cooler the battery pack is kept, the better the longevity will be. No way around that.
     
  17. lolachampcar

    lolachampcar Active Member

    Joined:
    Nov 26, 2012
    Messages:
    4,451
    Location:
    WPB Florida
    and what happens when the temperature plummets? Without active thermal management, will the car even function?

    Also, when was the last time VAG was remotely interested in product longevity? VW is particular has falling to pieces just after the warranty expires down to a science.
     
  18. JST

    JST Active Member

    Joined:
    May 23, 2013
    Messages:
    1,506
    Are "active thermal management" and pack heating the same thing? I sort of assumed that the former just meant the fluid-cooling that Tesla uses, and that the pack heating was done by a separate resistance element, but I realize I don't really know that to be true.

    - - - Updated - - -

    Are "active thermal management" and pack heating the same thing? I sort of assumed that the former just meant the fluid-cooling that Tesla uses, and that the pack heating was done by a separate resistance element, but I realize I don't really know that to be true.
     
  19. ecarfan

    ecarfan Well-Known Member

    Joined:
    Sep 21, 2013
    Messages:
    10,365
    Location:
    San Mateo, CA
    To me "active thermal management" means keeping the battery as close as possible to its optimal temperature range. That can involve heating or cooling depending on environmental conditions and power demands imposed by the user (driver and/or passengers).
     
  20. lolachampcar

    lolachampcar Active Member

    Joined:
    Nov 26, 2012
    Messages:
    4,451
    Location:
    WPB Florida
    jst,
    maybe a bad assumption on my part as well. When someone says passive, I think no cooling or heating. They may be heating.
     

Share This Page