Ragone plots for battery discharge optimisation

Ragone plots are a useful aid to compare the performance of different energy storage devices. For batteries, the energy is typically plotted against the power for a constant power discharge. It is typically assumed that the terminal voltage is fixed. This paper extends the analysis of a Ragone plot to understand how the formulae derivation for the Ragone plot of a battery can be modified to deal with varying terminal voltage. The paper includes the theoretical derivation and then shows how this is important in battery management systems by showing how it can be used to optimise battery string performance.