Featured 6 year lead on EV Computers

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by Prodigyplace, Feb 17, 2020.

  1. bwilson4web

    bwilson4web i3 and Prime

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    A complete battery assembly that incorporates the cell-to-cell connectivity could be made as a single, integrated part. Redundancy to work around a single failed cell would be no more difficult than what we have today. For example, this is a six cell battery assembly:
    [​IMG]
    The open top, cell-to-cell, limits the maximum voltage. However, closing each cell is trivial and allows higher terminal voltages. There remains a non-trivial problem of thermal management channels. Cell chemistry is the next challenge.

    Source: Types of Lithium-ion Batteries – Battery University

    [​IMG]
    NCA has twice the energy density of LFP. For vehicles, weight is key and higher energy density is always more desirable. For stationary battery systems, LFP would be fine.

    So I can imagine a single battery body with circular cell holes closed on one side. A machine rolls and inserts the "jelly roll" into each cell hole in a single block. A parallel, 20 cell, group would lose only 5% of the capacity should one cell fail. The top cover would then seal them to complete the pack. Then thermal management is the next challenge.

    Rivian claims they can achieve adequate thermal management from the end of 21700 cylindrical cells. Although it could work, the problem is the limited surface area to pass the heat. IMHO, cooling channels should be part of the block as passage holes.

    Bob Wilson
     
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  2. Trollbait

    Trollbait It's a D&D thing

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    This came up in another thread. Tesla's choice here has nothing to do with which has a technical advantage. It is about lower cost, and not straining their 21700 supply for the Chinese market. These are only going into the Model 3 SR there, no where else. LG Chem is also supplying some batteries for this market, with the majority being the 21700 from Panasonic.

    LiFe isn't a poor chemistry; it just isn't the best for cars. While lower energy density, they are also longer life and safer. I would not be surprised with Tesla using it for stationary power supplies in the future.

    China has been using LiFe in EVs for years now. Most of their EV buses uses them. With the available space in the Model 3 SR's floor, they should work well for the target range. Tesla will also get to study CATL's moduleless technology.

    I don't know how much this is short notice. Tesla working with CATL was reported before, just not the details on the battery they were supplying.
    Using local suppliers was likely part of the deal with building the factory.
     
  3. El Dobro

    El Dobro A Member

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  4. Fred_H

    Fred_H Misoversimplifier

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  5. Trollbait

    Trollbait It's a D&D thing

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  6. bisco

    bisco cookie crumbler

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    Seuss stated that they would be satisfied to ‘keep up’ for now.

    Maybe his English needs work, I’m sure he meant ‘catch up’
     
  7. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    Of course. All the good software engineers were the ones tasked with fixing the diesel emissions "bug" and have been fired.

    Mike
     
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