Assessing the Performance of Model-Based Energy Saving Charging Strategies in Li-Ion Cells

Li-ion batteries are widely employed as sources of portable energy. Advanced Battery Management Systems (ABMSs) rely on models to optimize battery performance (e.g. time-charge, life-time). The aim of this work is to assess if an energy efficiency improvement with respect to standard charging protocols can be obtained from model-based optimization in the time or in the frequency domain. Time-domain optimization is first considered and it is shown that only negligible improvements can be obtained. Then, motivated by successful experiments (e.g. [1], [2]), frequency-domain optimization is also investigated. Within this context, we prove that linear models are inadequate for providing any improvement. Surprisingly, even the mostly used electrochemical model available in literature (P2D), fails to capture the energy dissipation reduction with sinusoidal input current. These results show that currently available models are not suitable for the design of model-based energy saving strategies.