[hwillis]

That hasn't been true for a very long time. Tesla uses their own chemistry[1] and has put in extensive work improving it. One of the higher-profile changes was that they use 1-2% silicon (Musk mentioned this in a stockholder call), which panasonic still hasn't rolled out to the rest of their batteries.

[1]: https://electrek.co/2017/05/04/tesla-battery-researcher-chem...

[mikeash]

I think people get confused because it's widely (and correctly) reported that Tesla uses 18650 cells. The confusion is that people think that's a model number, but it's actually just a size and shape. It's literally 18x65mm and the 0 means it's round. It tells you nothing at all about what's inside the cylinder.

[sapienthomo]

NCR18650B is a specific series of parts from Panasonic(/Sanyo). If you want literally the exact battery that Tesla uses in the S, call Panasonic and tell them you want a shipment of ten million NCR18650BF (the new one with the silicon anode. The identity of these parts has been confirmed multiple times by people tearing down the battery packs (where they get this kind of disposable income, we don't know) and comparing the size/weight/discharge characteristics of single cells.

The "advanced chemistry" that Tesla moved to after a year of S production was a SiO-doped anode, exactly the difference between the B and BF part numbers from Panasonic-Sanyo. The cells weigh a gram less. This makes the charge density appear higher when the denominator is in terms of mass.

Tesla has done a wonderful job of selling their brand and convincing people that their batteries are other than off-the-shelf technology. In reality the same chemistry is available to anyone who calls up Panasonic and orders a hundred million batteries.

[mikeash]

Do you have links? All I'm turning up with search terms like "NCR18650BF tesla teardown" are people using that as the closest point of comparison or speculating.

[sapienthomo]

I don't think those have ever been used in the model S.

[hwillis]

Tesla has used a customized chemistry since just after the launch of the model S. Tesla literally has their name on the talk from that link. Do you think they're just doing research for fun?