Overview of batteries State of Charge estimation methods

In the present, electric and hybrid electric vehicles are more and more common. Usually, the main source of energy are batteries. To achieve optimal utilization and protection of batteries, battery management is used. This battery management system prevents batteries from overdischarge and overcharge and provides cell balancing. Accurate state of charge estimation is necessary for these tasks. There are several methods for state of charge determination which can be divided as direct measurement methods, book-keeping methods, adaptive methods and hybrid methods. In this article, commonly used state of charge estimation methods, advantages and disadvantages are described.