Review on grid-tied modular battery energy storage systems: Configuration classifications, control advances, and performance evaluations

In the past decade, the implementation of battery energy storage systems (BESS) with a modular design has grown significantly, proving to be highly advantageous for large-scale grid-tied applications. However, despite its increasing prevalence, there is a noticeable absence of review papers dedicated to this specific topic. This paper aims to address this gap by presenting a comprehensive overview of modular BESS, covering various aspects such as the classification of modular electrical configurations into four types based on parallel or cascaded connections at the dc or ac side, and providing real-world examples of in-field applications. Further-more, the paper summarizes the diverse control methods employed in modular BESSs, including power flow control, fault-tolerant control, and battery balancing control. It also presents detailed performance evaluations for different modular BESS configurations, encompassing aspects such as efficiency, cost, battery management, etc. Additionally, this review paper discusses prospective avenues for future research in the field of modular BESSs, offering valuable insights and guidance for their development and application. By providing a compre-hensive analysis of modular BESS for practicing battery engineers and aspiring researchers, this paper contributes to the understanding and advancement of this technology, thereby facilitating its integration and utilization in forthcoming applications.