At the beginning of Tesla, the Tesla roadster, the young manufacturer had copied the idea of AC Propulsion (the true creator of the modern electric car), to make a car battery with very small battery cells, the same as there are in laptops. This idea prevailed until the Model S Plaid, which even today uses some 7,000 small cells assembled alongside each other. They are small round cells, named 1865 (also called 18650), because they have a diameter of 18 mm, for a height of 65 mm. It works very well, cars have proven it a thousand times, but we still think that it would be simpler, and probably smarter to use larger cells.
In a Volkswagen ID.4 77 kWh battery, for example, the battery has only 288 cells. Tesla is well aware of this, in the Model 3, he uses a slightly larger cell, 2170 (diameter of 21 mm, height of 70 mm), but last year, he had given the idea of a much larger cell, the 4680 (diameter of 46 mm, height of 80 mm). According to him, these dimensions form the best compromise between manufacturing cost, volume density, energy density… Panasonic, Tesla’s technical partner for batteries, today presents the first prototypes. They should be in regular production next March, to equip Tesla cars at the end of the year.
These new cells should allow Tesla cars to display a better range, with more on-board energy, or to be lighter or cheaper with unchanged battery capacity.
We are still waiting for the full characteristics of these future battery packs, but we will already note that a 4680 cell is 5.5 times larger than a 2170 cell, and 8 times larger than an 1865 cell. It would therefore be theoretically possible to replace the battery of a Model S with 7000 cells 1865, by a battery composed of 875 cells 4680. But, there are many possibilities…