Parameter determination and evaluation of a Thévenin dynamic model for a li-ion cylindrical cell used in CubeSat applications

The limited processing capacity of the lean satellites means that the indicators describing the general state of the cells that make up their power subsystem are rarely estimated. Such is the case of the SOC, whose estimation will be relevant for the control of this subsystem during the mission. Following the idea that these satellites seek a low cost, in this work, a cost-effective cycler was integrated to obtain the parameters of the cells. These were used as the input data of a Thévenin equivalent circuit model with one RC pair to obtain the estimated SOC. The Coulomb Counting method was chosen to calculate the real SOC from simulated data of the BIRDS mission. The results were evaluated and compared with simpler methods to demonstrate their accuracy. A mean absolute percentage error (MAPE) of 1.00337% was obtained, showing that the selected Thévenin model produced precise results without compromising processing power for other functions during the satellite mission.