On the Use of Dimensionless Parameters for Fast Battery Performance Analysis

Dimensionless analysis arises as an appropriate methodology to study battery cells behavior since it brings the opportunity to identify limiting mechanisms in the battery cell performance by analysing a reduced number of dimensionless parameters. These parameters are obtained by condensating the physical dimensional parameters involved in the description of the electrochemical phenomena taking place in the cell. Here, based on the well known Doyle, Fuller and Newman model [M. Doyle, T.F. Fuller, J. Newman, J. Electrochem. Soc., 140(6) 1526-1533 (1993)] (DFN model, in short), a comprehensive set of dimensionless parameters is derived and the information arising from each dimensionless parameter is explained. Application to the design of a solid polymer electrolyte cell is considered, where limiting transport mechanisms are identified through dimensionless parameters analysis and guidelines for a cell redesign are also drawn from this analysis. Predictions made by inspection of the derived comprehensive set of dimensionless parameters are validated both numerically (using the DFN model) and experimentally.