Gravimetric and Volumetric Energy Density of a Battery

Question

I have a thermodynamics homework question: "A common D size nickel metal hydride battery will supply 10,000 mAh of charge. What are the gravimetric and volumetric energy densities of this battery?"

Answer 1

Hi Ayda, great question.

First, let's look at the definition of both gravimetric and volumetric energy densities.

Gravimetric energy density (otherwise known as specific energy) is defined as a battery's energy capacity per unit weight (Units: Wh/kg).

Volumetric energy density (sometimes referred to as just energy density) is defined as a battery's energy capacity per unit volume (Units: Wh/L).

So, for this problem, all you need to find is the weight and volume of a standard D size nickel battery and use the definitions of gravimetric and volumetric energy density. Let me know if you have any more questions!