Vanadium redox battery parameter estimation using electrochemical model by reduced number of sensors

The voltage and current sensors are normally necessary to estimate parameters of batteries like redox flow batteries. The estimable internal battery parameters are normally the state of charge and the available capacity of the battery in charging and discharging modes. These sensors have inherent delay and error, which result in error and delay in estimations of the battery parameters. The cost of these sensors also increases the total cost of the battery system. Therefore, this research aims to propose algorithms with a reduced number of sensors to estimate the parameters of Vanadium redox flow batteries. An algorithm is introduced in the current study in discharging mode with only a voltage sensor and without current sensor, and further, the battery current is estimated. Another algorithm is proposed in charging mode without current and voltage sensors; further, the battery current and terminal voltage are estimated. The proposed algorithms are based on the electrochemical model of the battery. The algorithm is tested in discharging mode, and the results show the Root Mean Square (RMS) error of 0.39 for the estimated battery current. In charging mode, the proposed algorithm is verified via two CC-CV charging datasets, and the results show the RMS errors of 0.29 and 0.61, respectively for the estimated battery current. The estimation errors in charging and discharging modes are considerably low, and further, the state-of-charge and the capacity of the battery are also estimated.