Validation of a Single-Cell Reference Model for the Control of a Reconfigurable Battery System

This paper presents the experimental validation of a lithium-iron phosphate cell model. The modelling of dynamic cell behaviour is crucial to improve the performance of reconfigurable battery systems, in which monitoring of the dynamics allows more resoluted leveraging of the battery cells. However, the models of lithium-ion cells are generally inaccurate due to nonlinearities, measurement noise and because the most descriptive state, the state of charge is hidden. Furthermore, the parameter identification of the model requires time and precise measurements, while they differ among the cells, and change as the cells age. The burden of the detailed modelling of a battery system can be alleviated by modelling a single cell, and using the model for each cell in the system. In this work, this possibility is explored by validating a single-cell reference model for a reconfigurable battery system. The terminal voltage residual (error between model and measurement) is presented, and its correlations with internal and external variables are investigated. These correlations can also be used to alleviate the modelling errors. It is concluded that the reference model can qualitatively describe the cell behaviour. By applying small modifications, the model could be used for online estimation.