Review on state of charge estimation techniques of lithium-ion batteries: A control-oriented approach

Energy storage has become one of the most critical issues of modern technology. In this regard, lithium-ion batteries have proven effective as an energy storage option. To optimize its performance and extend its lifetime, it is essential to monitor the battery’s state of charge. Due to the distinct nonlinear behavior of batteries over their lifetime, the state of charge estimation is challenging. The challenge has been establishing a relationship between accuracy, robustness, and low implementation complexity. Over the last decade, numerous attempts have been made to effectively analyze and compare the state of charge estimation methods for commercial lithium-ion batteries. However, they seldom reflect on the state of charge estimation techniques based on a control-oriented viewpoint for a Li-ion battery system. To fill this gap, this paper reviews the most up-to-date battery state of charge estimation methods applied to lithium-ion battery systems. They are broadly classified as open-loop-based, closed-loop-based, and hybrid approaches. Finally, the paper concludes by providing an analysis of the positive and negative aspects of the reviewed techniques and some suggestions for future research.