Tesla has revealed some interesting details regarding their new 2170 battery cells in a letter to shareholders. The batteries, which will be used in the Model 3, had previously not been publicly discussed.
The battery cells have the “the highest energy density cells used in any electric vehicle”. According to Tesla, this was done by significantly reducing the cobalt share in the mix, while increasing the amount of nickel, which allows for a “superior thermal stability”. The manufacturers further stated that the cobalt content in the Nickel-Cobalt-Aluminum cathode chemistry is already lower than that of next generation batteries by competitors.
Panasonic has been producing the battery cells since June 2017 in the Nevada Gigafactory 1. Beyond that, Tesla has been using their established 18650 batteries in their other vehicle models.
The following youtube video shows the interior life of the 2170 cell, and demonstrates the differences between the Model S and Model X cell construction. We also recommend NOT to try this at home.