Aging Effect on Lithium-Ion Battery Resistance Hysteresis

In recent years, lithium-ion batteries have been broadly employed in many different applications that require high energy and power density. In both static and mobile applications, the onboard estimation of internal parameters such as the capacity and internal resistance is of paramount importance. In particular, the internal resistance of a battery limits the power it can deliver and affects the overall efficiency. The battery resistance changes under different conditions, such as temperature, state of charge, and aging. In addition, a hysteresis resistance phenomenon was discovered and analyzed for different temperatures in a previous work. Indeed, the internal resistance of a battery changes based on the charging or discharging phase for a fixed state of charge and temperature. In the present work, the hysteresis phenomenon was deeply analyzed, even considering the cycle aging of the battery. To do this, several tests were performed using the electrochemical impedance spectroscopy method. Finally, a mathematical model capable of predicting how the hysteresis changes as a function of aging, for a fixed state of charge and temperature, was proposed.