Dissecting A 2170 Battery Cell – Video


If you ever wondered what’s inside the 2170 Tesla battery cells that are produced in Gigafactory 1 by Tesla in partnership with Panasonic, her’s your answer.

Tesla 2170 battery cell

ARIES RC discharged and disassembled a cell obtained in some way (allegedly) from the Gigafactory.

The 2170 cylindrical cells are bigger than the previous 18650 cells, so it stores more energy. However, the video doesn’t contain a capacity test.

The video is entitled Tesla Model 3 battery, but in general the same format is used in new Powerpacks and Powerwalls.

Several thousands of these cells are needed to build the Model 3 battery pack for 310 miles range (EPA).

*Disclaimer: Don’t try this at home. It’s dangerous if not done right.

Category: Battery Tech, Videos

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16 responses to "Dissecting A 2170 Battery Cell – Video"
  1. John says:

    So where are all the liquids? This is Solid State?

    1. Aaron says:

      It’s a tar-like substance inside. No liquids.

    2. Fred says:

      THe liquid gets injected. It is quite volatile, so it might have evaporated or just ran out as he opened the cell.

  2. John says:

    I’m amazed people don’t understand basic geometry. The cell might have 30% more energy, but it takes more space so you can fit less cells in the pack.

    1. Derek says:

      Yes its bigger, but ignore the size. The new cell is 10-15% more energy dense, regardless of size.

      1. Or, instead of “its bigger, but ignore the size. The new cell is 10-15% more energy dense”, try this: ‘it’s bigger in size, plus the new cell is 10-15% more energy dense!’ (Which, when combined, leads to fewer external connections to make, to get a desired kWh pack capacity!)

      2. Ambulator says:

        Have all the 18650s been at the same energy density? If not, which one were they comparing the new cell to.

        1. Pushmi-Pullyu says:

          No, Panasonic’s 18650 li-ion cells have absolutely increased in energy density over time.

          Your second question is indeed the crux of the matter. You can see older claims that the new cells have up to 30% better energy density, but that’s likely comparing the 2170 cells to the 18650 cells that Panasonic was making in 2012, when the Model S first went into production.

          We can hope that the 10-15% improvement in energy density is a comparison with the cells that Tesla is currently using in the Models S and X, but anyone who could say that with any certainty has signed an NDA with either Panasonic or Tesla.

    2. John says:

      I think they used calculus to come up with the optimum size for highest e-density. Simple geometry,It’s not

  3. sveno says:

    Yes it is a 2170 cell but I don’t believe that it’s coming from the Gigafactory. Panasonic isn’t the only one making them now.

    1. Pushmi-Pullyu says:

      I’ve seen a plausible claim that Panasonic made some 2170 test cells in its factory in Japan, before the Model 3 went into production. But so far as I know, only Gigafactory One is actually mass producing 2170 cells, and all 2170 cells which Tesla is using in the Model 3 come from Gigafactory One.

      1. sveno says:

        Are you saying that Gigafactory produces bare 2170 cells for 3rd parties at this stage?

  4. ylgmac says:

    bigger cells means that it also take less place for packaging of each cells.
    It’s an important factor, less cell’s could also need less fluid for cooling….

    1. Terawatt says:

      It’s very entertaining when people as clueless as you try to explain engineering…

      I am certainly no battery expert, bit even I understand that your explanation is a total misapprehension. The larger the cell volume, the less surface area there is relative to energy and power. An advantage of Teslas thousands-of-small-cells approach over those who use much fewer and much bigger pouch or prismatic cells is that it’s easier to provide effective cooling and achieve a more even temperature in the pack.

      If energy density was the only concern a single gigantic cell would maximize it. Of course it would also be impossible to cool properly, a fire hazard, an explosion hazard, and provide only 3.7V, therefore needing a hundred times as large currents, but it would maximize energy density…

  5. Some Guy says:

    Well, at least the dude in the video is wearing some gloves while unwinding (other videos show people touching the stuff with bare hands).
    But clearly he has no idea about battery manufacturing or how they are structured internally:
    – The black powder that drops to the table comes off the copper foil, so clearly it is graphite from the anode. It usually happens in deep discharged cells.
    – Ultrasonic welding of the tab lead nickel strip to the thin current collector foil (that copper thingy) has been state of the art for decades. Every lithium ion battery out there to buy has it done this way (perhaps aside from some artisanal batteries from China with fraudulent capacity specs). The aluminum current collector (with the cathode on) has a similar connector.
    – The plastic on the inside of the cell can is an adhesive. It prevents the electrode roll from moving around during filling of the cell with electrolyte and closing (it is moving very fast while this is done).
    – The three tiny holes on top are not for venting in case of emergency. That’s what the big ring structure at the bottom of the can is for. Far more effective than three tiny holes.
    – the outer part of the copper foil is blank, but not for grounding purposes, but material savings (there is no opposing cathode, so the material would be inactive)

    A simple look at some enginnering sites or wikipedia before doing such a video might have been helpful, so others could profit from it otherwise than learning the length of the electctrode rolls.

    As for the cell itself: Could be from GF1, but could also be from Panasonic Japan or Samsung (type -48G) or other manufacturers. They use similar casings, and the latter ones can be purchased online for a few bucks each. Only thing for sure is that the cell from the video was never installed in a vehicle. Otherwise there would be welding residue on the bottom and top of the can.

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