Diagnosing overcharge behavior in operation of Li-ion Polymer batteries

In this paper, overcharging effects of Li-ion polymer cells were investigated and classified with respect to vehicle safety concerns. An advanced cell model is proposed providing better State of Health (SoH) determination for overcharge behavior in operation of Li-ion Polymer batteries. Li-ion polymer cell kinetic parameters were obtained using Electrochemical Impedance Spectroscopy (EIS) method and changes in these parameters were analyzed theoretically in cases of forced charging. Cell equivalent circuit was improved and additional parameters detected according to overcharge states. This yields a better detection and diagnosis capability for Battery Management System (BMS). These equivalent circuits and experimental results provide better classification when defining the irreversible changes caused by overcharging.