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

Battery Format for Model 3 - 18650 commodity cells or large format batteries

Discussion in 'Model 3' started by Reeler, Mar 12, 2016.

?

What cell format will Tesla use for the Model 3?

Poll closed Mar 30, 2016.
  1. Commodity 18650 cells tuned for auto applications just like all their other cars

    50.0%
  2. Large format cells just like all other auto manufacturers with their own battery factory

    50.0%
  1. Reeler

    Reeler 6 Years of Pure EV

    Joined:
    Oct 14, 2015
    Messages:
    650
    Thus far, the Roadster, Model S and Model X have used commodity 18650 format cells. Other manufacturers with their own factories have instead gone for large format cells. Tesla's decision was pragmatic in that economies of scale kept costs low, but that much wiring is complex and has other issues.

    Now that Tesla will have their own battery factory, I don't personally see any reason not to follow what everyone else has done--large format batteries. I predict that this will happen with the Model 3 release and completion of the Gigafactory. What do you think?
     
  2. Jason S

    Jason S Model S Sig Perf (P85)

    Joined:
    Apr 20, 2012
    Messages:
    1,350
    Location:
    Rocklin, CA
    Something in between. I recall seeing mention of a little bit larger cell than the 18650 -- but I don't recall the name of them.
     
  3. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
  4. aronth5

    aronth5 Long Time Follower

    Joined:
    May 8, 2010
    Messages:
    1,436
    Location:
    Boston Suburb
    This or something very similar in size.
     
  5. Lex

    Lex Member

    Joined:
    Apr 23, 2015
    Messages:
    658
    Location:
    Toronto, Canada
    This is really interesting stuff. Are we sure they're still going to use a similarly sized cylindrical cell, in general ? The Lithium Ion packs in my cellphones are not cylinders. The one in my old Motorola Razr (the rebooted one) was even highly soft and bendable.

    What about the GM cells, are they cylindrical inside the "packs" ?

    I watched a pile of Elon Musk interviews this weekend and one "a-ha" moment he shared was the team asking what the "ingredients" were in a battery, and what the commodity market costs were, to start with a base input cost. And then later, they.... :cool:
     
  6. Crankstart

    Crankstart Member

    Joined:
    Feb 4, 2016
    Messages:
    8
    Location:
    Kansas City
    GM uses LG Chem flat battery cells in the Volt. Not sure about the Bolt, but expect same/similar
     
    • Informative x 1
  7. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,032
    Location:
    Delaware
    GM uses LG Chem Prismatic (rectangular) cells for all of their EVs to date - a smaller number of much larger, much more powerful cells. - the original Volt has only 288 cells (a 96 group series string of parallel triplets,) and the new Volt and Spark are actually even fewer despite the larger capacity - 192 cells arranged in pairs.

    This approach makes manufacturing simpler, but the failure of a single cell has significant consequences for the car as a whole, so the battery supplier has to have extreme quality control in place (and mostly seems to - the Volt has been putting up a pretty impressive reliability history.)

    Tesla took a RAID approach instead - they have 74 cells in parallel in each of their 96 series groups (6 groups in each of the 16 modules,) each individually fused and isolated in intumescent goo (in the original 85 kWh packs, anyway - the others are similar in concept.) This increases the odds of failure, but it allows a cell to fail without having significant impact on the car as a whole - the fuse pops, but as long as the coolant and goo are enough to stop a thermal runaway, the event ends there - and the car lost 1.4% of its range, with the odds strongly against the next failure costing any additional range.

    It'll be interesting to see which approach ends up dominent in the industry...
    Walter
     
    • Informative x 2
    • Like x 1
  8. Jeff N

    Jeff N Active Member

    Joined:
    Oct 31, 2011
    Messages:
    1,132
    The Bolt uses 96 groups of 3 cells for 288 total (same count as the 1st gen Volt). The flat cells are about 3.9 inches high and 13.1 inches long.
     
    • Informative x 1

Share This Page