I. Introduction
During the last years, the technology advancements of the lithium batteries have made them one of the popular choices for the implementation of battery energy storage systems (BESSs). Nevertheless, the connection of many lithium battery cells in series, to create a high voltage stack, requires the appropriate monitoring to ensure that all cells operate within the safe operating region that is specified by the manufacturer. In addition, manufacturing or environmental factors may introduce dissimilarities among the cells of the battery pack. As a result, during multiple cycles of charging and discharging, these dissimilarities may result in damage of the cells and compromise the safety of the application.