A Battery Pack Coupling Coefficient for Scaling a Cell Electrical Model for an All Electric Aircraft Application

This work regards a battery pack modelling method for an All-Electric Aircraft application (AEA). The methodology consists of evaluating the Equivalent Electric Circuit (EEC) of a single cell and afterwards scaling it up for the battery pack, taking into account the inconsistencies that arise either during the cells’ production or the pack’s grouping stage. The single cell model was carried out resorting to the charge and discharge cycling tests and the DC pulsed tests. In particular, the Hybrid Pulse Power Characterization (HPPC) allowed for the second-order Thevenin model parameters estimation. The coupling factor scales the cell model to the battery pack level by considering its inconsistencies. The real pack transformation ratio was determined by comparing the theoretical cell-based battery pack with an experimental voltage profile. The procedure was performed on both the weakest and a random cell of a 6s1p battery pack. The comparison highlights a good overlap between experimental and simulated pack voltages with an average error of 0.2%.