In energy transformers including batteries, fuel cells, motors, etc., and also power supply units or similar, power density refers to a volume. It is then also called volume power density, which is expressed as W/m3.
Volume power density is sometimes an important consideration where space is constrained.
Power densities of common materials
|Storage material||Energy type||Specific power (W/kg)||Power density (W/m3)|
|Hydrogen (in star)||Stellar fusion||0.00184||276.5|
- Energy density, energy per unit volume
- Power-to-weight ratio/specific power, energy per unit mass
- Specific absorption rate (SAR)