amount of energy that a battery can store per unit of volume or mass, providing an indication of the capacity of a battery to store electrical energy

NOTE 1 Energy density of a battery is typically measured in watt-hours per unit volume or mass, e.g. watt-hours per kilogram.

NOTE 2 High energy density is desirable for applications that require a compact and lightweight energy storage solution with a large capacity.

NOTE 3 Energy density is distinct from power density, which is more relevant for applications that prioritize the rate of energy delivery over energy capacity.

NOTE 4 Other terms commonly used with regard to energy density per unit mass include “specific energy” and “gravimetric energy density”; and with regard to per unit volume, “volumetric energy density”.