Cylindrical lithium-ion battery models utilize a five-digit numerical coding system:
The first two digits indicate the diameter (in millimeters).
The middle two digits indicate the height (in millimeters).
The final digit is fixed at 0 to denote a cylindrical shape. Common cylindrical lithium-ion battery models include the 10440, 14500, 16340, 18650, 21700, 26650, 32650, and others.
As of July 2024, the primary models include:
10440: 10 mm diameter; used in miniature devices.
18650: 18 mm diameter; a mainstay model for small electronic appliances.
21700: 21 mm diameter; used in electric vehicles.
4680: 46 mm diameter; a new, high-capacity format.
