[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.