20700

20700 is a cylindrical lithium-ion battery cell format used in rechargeable energy storage. The name refers to its approximate dimensions: about 21 mm in diameter and 70 mm in length, making it larger than the common 18650 format and smaller than some 21700 cells. There is no single official standard; dimensions may vary slightly by manufacturer.

The cells typically have a nominal voltage of 3.6 to 3.7 volts and a fully charged voltage of 4.2 volts. They are produced with various chemistries, most commonly nickel manganese cobalt (NMC) or lithium nickel cobalt aluminum oxide (NCA) for high energy density, or lithium iron phosphate (LFP) in some cases. Capacity depends on chemistry and build, commonly ranging from around 2000 to 5000 mAh, with higher energy-density variants used in power packs.

Applications include electric bicycles, power tools, energy storage systems, and some high-drain devices where a higher energy capacity per cell is required than 18650 but not as long as 21700. They are used in packs designed for consumer, industrial, and automotive applications, though they are less ubiquitous than 18650 or 21700 formats.

Manufacturers produce 20700 cells for inclusion in packs; designers must account for the slightly different dimensions when replacing cells or designing new packs that use 20700 cells. Safety considerations follow standard Li-ion guidelines, including proper charging, thermal management, and protection circuitry within battery packs.