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NHTSA Opened Up the Model S Battery Pack - Pics

Discussion in 'Battery Discussion' started by EarlyAdopter, Sep 23, 2013.

  1. EarlyAdopter

    EarlyAdopter Active Member

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    I don't think I've seen this posted anywhere here, but if you dig through the report documentation from the NHTSA crash testing of the Model S after the pole side-impact test they opened up the traction pack for examination and included photos in the report. These are the first I've seen of a wide open Model S battery pack. Note the minor denting on the driver's side middle of the pack from the impact with the pole.

    v08309R002_Page_31.jpg

    v08309R002_Page_32.jpg

    Untitled.png
     
  2. vfx

    vfx Well-Known Member

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    OK, start countin!
     
  3. yobigd20

    yobigd20 Well-Known Member

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    it looks like there are some missing batteries

    - - - Updated - - -

    hard to tell, but I see about 31 cells in each row, 14 rows per section, and 7 sections. 31x14x7=3038 batteries. Are they double stacked or am I blind?
     
  4. JRP3

    JRP3 Hyperactive Member

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    #4 JRP3, Sep 24, 2013
    Last edited: Sep 24, 2013

    LOL, my first thoughts as well :biggrin:

    Looks like 32 or 33 in each row to me, still not enough.
     
  5. aronth5

    aronth5 Long Time Follower

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    No you are not blind just don't tell anyone but those are the new 6.2Ah top secret batteries:smile:
     
  6. brianman

    brianman Burrito Founder

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    If you compare the first picture (figure 13) with the other 2 (figures 15*), there are two blocks of the ones that yobigd20 was counting.

    Also, I count 32-33.

    So figuring that...
    2*32*14*7 = 6272
     
  7. Wattson

    Wattson Member

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    In figure 15A, you can see the exposed area is just half of the pack. See the butterfly construction, there's another mirrored side. Multiply your counts by two.

    - - - Updated - - -

    Replied at the same time. Brianman beat me to it.
     
  8. JRP3

    JRP3 Hyperactive Member

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    #8 JRP3, Sep 24, 2013
    Last edited: Sep 24, 2013
    Still substantially below the 7000+ cells we've been told and have calculated are needed to build an 85kWh pack. Even if we use 33 cells per row that gives us 6468.
    If that number is correct then Tesla would need to use a 3.65 ah cell to get 85kWh, assuming a 3.6 nominal voltage.
     
  9. PV4EV

    PV4EV Member

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    Looking through the NHTSA documents, one of the photos shows the car is a 60kWh. Does the smaller MS ESS have less 18650s ? Did they keep overall vehicle weight and dynamics the same using ballast of some sort ?
     
  10. jthompson

    jthompson JThompson

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    Thank you, Early Adopter, for posting this! This is the kind of stuff I love to learn about my Model S!!!
     
  11. yobigd20

    yobigd20 Well-Known Member

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    Yes! If you look at the "empty battery" areas between the two photos they are different! Nice catch.
     
  12. AnOutsider

    AnOutsider S532 # XS27

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    That's what I was thinking. I'm also wondering what the damage would have been if the pole had hit at a midpoint between those support bars. A couple cells ruptured? I also wonder if, like the fixed headrests, Tesla designed those supports at the exact position for the tests.
     
  13. scaesare

    scaesare Active Member

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    No pictures of the taller front "nose" of the pack. I've seen various claims about that portion of the pack: 2 more battery sheets stacked atop each other, a reservoir for the battery coolant, or the active electronics module for the pack.

    They indeed mention 14 battery sections "sheets" within the pack, and that it's a 60KWh pack... so I wonder if they missed 2 up front, or if that's correct.
     
  14. jthompson

    jthompson JThompson

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    Page A-7 of the Indicant Test report shows the 60kWh sticker.
     
  15. JRP3

    JRP3 Hyperactive Member

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    I've never thought that was correct.
     
  16. stopcrazypp

    stopcrazypp Well-Known Member

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    #16 stopcrazypp, Sep 24, 2013
    Last edited: Sep 24, 2013
    The information I have so far shows evidence of 16 modules for the 85kWh and likely 14 modules for the 60kWh.

    We know from the diagnosis screen that the 85kWh pack has 16 modules with 6 groups in series (so 96 groups in series):
    https://lh5.googleusercontent.com/-csWFYzE8OE8/UCnVgOsCo1I/AAAAAAAATUE/Ngjz-jlZMYc/w702-h498-no/IMG_0876.JPG

    We know the pack is structured with 14 modules in the flat section and 2 modules stacked in the front where the coolant connectors are:
    http://www.teslamotorsclub.com/showthread.php/16535-Battery-facts?p=333846&viewfull=1#post333846

    Charging voltage shows evidence of there being 14 modules (or equivalent) in the 60kWh pack:
    60kWh 352V (14 modules in series *6 series group per module*4.19V)
    85kWh 402V (16 modules in series *6 series group per module*4.19V)
    http://www.teslamotorsclub.com/showthread.php/21625-Motor-battery-combo-performance-differences-S60-S85-and-P85/page3?p=445256&viewfull=1#post445256

    The NHTSA test data (page 6) seems to match this for the 60kWh pack:
    We had a previous guess of 7104 cells for the 85kWh (16*6*74), 14 modules for 60kWh means 6216 cells (14*6*74).

    Of course, the capacity math (85 vs 60) does not really work out using 16 and 14 modules, so that's the weird bit (maybe different capacity cells)
     
  17. JRP3

    JRP3 Hyperactive Member

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    Interesting, somehow I missed that graphic showing the front modules.
     
  18. rrosenbl

    rrosenbl Member

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    How did you get into that diagnostic mode screen? I'd like to snoop around behind the curtain while waiting to charge or if bored...
     
  19. vfx

    vfx Well-Known Member

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    At the original Tesla Factory opening an engineer told me there were batteries in the upper section "because they had room".

    Later JB said they could make a 500 mile car but they had to stop somewhere. I assume weight diminishing returns on that.
     
  20. scaesare

    scaesare Active Member

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    stopcrazypp-

    Yeah, that's the graphic I remember and the discussion of the two additional sheets in the pack "nose".

    i wonder if that space is simply empty in the 60KWh pack then... probably so.

    - - - Updated - - -

    Yeah.. that and cost.
     

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