Tesla batteries 18650 vs 2170


Well it is pretty incredible that all these fancy cars are basically filled with AA Lithium Ion batteries, that's not exactly completely true, but there is nothing that special. Here's the scoop on batteries.
The current Model X and S have 18650 Lithium Ion batteries. These are standard batteries that are 18mm in diameter and 65.0mm long (get the name 🙂 that you can buy on Amazon. They did this because laptops use the same batteries at the time so there were economies of scale compared with custom battery pouches.
They fit into cell modules. So the 100KwH battery is actually 516 cells in each module and 16 modules per car.
As an aside each battery has a maximum charging voltage and a maximum amperage. This is 4.2V and 2A. This sets a hard limit for Tesla charging (you want more cells so the 2A is the limit). For a 100KWh battery it is 138kW.
The Model 3 uses a different battery, handily this isn't standard but is 21mm x 70mm so larger and they are about 10-15% more efficient and 46% bigger. This means that for the same volume, if the Model X and S were to switch to the 2170 battery, they but delivers double the current at 6A vs 3A in the 18650.
It seems to have the same energy density but is lower cost to produce and generates more heat, but one of Tesla's advantage is the battery management system that handles the heat being generated.
Also the rumble is that these New batteries have a custom formulation. One thing is that they use very little cobalt (2% vs 8%) and that's not only expensive but has all kinds of issues with how it is mined.
The Gigafactory 1 in Nevada is designed to produce 35GwH of batteries which is 2x the total battery production in 2016!

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