This article presents a hierarchical state-of-charge (SOC) balancing control method for a battery energy storage system. In the presented system, multiple battery cells are connected in-parallel at the inputs of a single-inductor multiinput single output (SI-MISO) power converter to form a battery module and multiple battery modules are connected in series at the output to form the complete battery system or pack. The presented hierarchical controller is able to control the SOC (achieve SOC balancing) at both the cell level and the module level (between all cells that are effectively connected in series and in-parallel) while simultaneously maintaining bus voltage regulation at the battery system or pack output. This is achieved by using the presented modulation scheme for the duty cycles of the power converter switches. Theoretical analysis and results from a proof-of-concept experimental prototype are presented and discussed in this article in order to evaluate and validate the operation of hierarchical SOC balancing controller and battery system.

The estimation of the state of health (SOH) of lithium-ion batteries is a critical technology for enhancing battery lifespan and safety. When estimating SOH, it is essential to select representative features, commonly referred to as health indicators (HIs). Most existing studies primarily focus on HIs related to capacity degradation and internal resistance increase. However, due to the complexity of lithium-ion battery degradation mechanisms, the relationships between these mechanisms and health indicators remain insufficiently explored. This paper provides a comprehensive review of core methodologies for SOH estimation, with a particular emphasis on the classification and extraction of health indicators, direct measurement techniques, model-based and data-driven SOH estimation approaches, and emerging trends in battery management system applications. The findings indicate that capacity, internal resistance, and temperature-related indicators significantly impact SOH estimation accuracy, while machine learning models demonstrate advantages in multi-source data fusion. Future research should further explore composite health indicators and aging mechanisms of novel battery materials, and improve the interpretability of predictive models. This study offers theoretical support for the intelligent management and lifespan optimization of lithium-ion batteries.

This study presents a bi‐directional single‐inductor multi‐input single‐output battery system with state‐of‐charge (SOC) balancing controller. In the discharging operation mode of the battery system, the SOC balancing between multiple batteries is achieved by adaptively modulating the multipliers of the discharging rate of each battery cell, while maintaining the output voltage regulated at the desired value by modulating the average value of duty cycle of the power converter. The SOC balancing is achieved naturally during the operation of the system without extra energy dissipation or charge transfer between the batteries. In the charging operation mode, each battery can be charged independently by using the same bi‐directional power stage. The convergence ability of the SOC balancing controller is discussed and results obtained from a proof of concept experimental prototype are presented and discussed in order to evaluate and validate the operation of the controller and system.

This paper presents a closed-loop controller which regulates the voltage or current at both wireless power transfer (WPT) output and non-wireless power transfer (non-WPT) output simultaneously while using the same set of components. First, a power converter topology which has two types of outputs, a WPT output and a non-WPT wired output, is introduced. This dual-type outputs (DTO) power converter uses the same set of power components for the two outputs in order to eliminate the transmitter side circuit in a WPT system, which results in reduced cost and size. Second, a method is presented in order to independently control and regulate each of the two outputs (voltage and/or current) by using two variables, the duty-cycle and the switching frequency. The Dual-Variable Dual-Type-Output (DV-DTO) controller regulates the non-WPT output by modulating the duty-cycle of the switches and regulates the WPT output by modulating the switching frequency of the same switches of the DTO power converter. The theoretical basis and experimental prototype results, including those with dual battery charging, are provided in order to illustrate and validate the presented method.

This paper presents and evaluates a control scheme and a power electronics architecture for a Wirelessly Enabled and Distributed Battery Energy Storage (WEDES) system. It includes several independent battery modules (WEDES-MX modules) that transfer both power and information wirelessly to an On-Board Unit (OBU). Using wirelessly communicated State-Of-Charge (SOC) information from the WEDES-MX modules, the OBU part of the WEDES controller generates control commands and send them back to the WEDES-MX modules in order to control the amount of power/energy drawn from each WEDES-MX module and achieve SOC balancing. The presented controller also allows the WEDES system to maintain operation with a regulated bus voltage even if one or more WEDES-MX modules are removed or fail and under both balanced and unbalanced SOC conditions. The WEDES system with the presented WEDES controller when utilized in Electric Vehicle (EV) application, can allow for fast and safe exchange/swapping of WEDES-MX modules at an exchange station, home, or work and therefore potentially eliminating the range (mileage) anxiety issue that is associated with EVs’ range and the needed recharging time. The main objective of this paper is to present and evaluate the WEDES discharging controller for the WEDES system and present preliminary proof-of-concept scaled-down experimental prototype results.