Rapid Analysis of Charging Profiles of Lithium Ion Batteries Using a Hybrid Simplified Electrochemical Model

Persistent energy demands of portable electronic devices necessitate the development of efficient charging protocols for the lithium ion cells powering these applications. In addition to a minimization in charging time and cell degradation, an optimal profile needs to ensure the maximization of lithium intercalation in the electrodes. Thus an electrochemical understanding of the system is highly beneficial in the design of efficient charging profiles. In this work, in order to identify and assess charging profiles, the essential features of an electrochemical model is combined with a phenomenological nonlinear resistor description to develop a simplified hybrid electrochemical model for lithium ion cells. This structure of the model allows for the simultaneous fast evaluation of charging profiles at the same time capturing the essential physical processes. Common charging protocols rely on a constant voltage charging segment, which is implemented here by the use of a new implicit analytical expression obtained for the charging current. The model outputs in various conditions are compared with experiments conducted on a commercial battery. Subsequently, alternate charging candidates are assessed using the model. To highlight the capability of the model, cyclic charge-discharge studies are conducted to quickly assess the degradation effects of the various charging profiles.