Capacity up to 21700 cells

Mass production models of 21700 cells with graphite-only anode have reached 4500mAh capacity. On the other hand, 21700 cells with silicon oxide anode have various capacity ranges, starting from 5000mAh and 5800mAh.

The larger size of the 21700 cell enables it to store more energy, making it ideal for applications requiring high power capacity, such as electric vehicles and industrial battery packs. Its dimensions also contribute to better thermal management, ensuring safer and more efficient operation.

The 21700 cell weighs approximately 60–70 grams, depending on the manufacturer and specific chemistry. While slightly heavier than the 18650 cell, this weight increase is justified by its higher capacity and energy density.

The 21700 battery is a cylindrical lithium-ion battery with a diameter of 21mm and a length of 70mm. It offers a nominal voltage of 3.7V and a capacity of up to 5,000mAh, making it a powerful and efficient energy source. Its energy density ranges between 250 Wh/kg and 300 Wh/kg, depending on the chemistry.

21700 cell, as the name suggests, stands for a cylindrical cell with 21mm width and 70mm height. It was first introduced in 2017 by a Tesla and Panasonic collaboration. 21700 was introduced as an alternative to the long-running 18650 model, which was introduced by Sony in 1991.

The stronger heating and lower resistance of 21700 cells than the 18650 results in higher polarization in the 18650 and deviations between the voltage curves for the two formats at higher C rates. The 21700 has about 50% greater capacity and energy density than the 18650 for discharge rates up to about 3.75C.