Lipko D. Battery Management Systems with Battery Life Extension Functionality

Lipko D. O. Battery Management Systems with Battery Life Extension Functionality. – Qualification Scientific Work as a Manuscript. Dissertation for the degree of Doctor of Philosophy in specialty 171 Electronics – National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute" MES of Ukraine, Kyiv, 2025. In the dissertation, the actual scientific and practical problem of extending the service life of accumulator batteries through the use of new means of power and information electronics is solved. The obtained new scientifically based results in the aggregate are significant for the development of battery management systems with an active balancing method, which can be used in batteries with a modular structure. In recent years, the production of electric vehicles, stationary energy storage devices and various portable devices has been growing significantly. This contributes to the fact that the production of lithium-ion batteries has been increasing very rapidly recently. Battery management systems are used in all modern battery packs. Their main task is the efficient and long-term use of the battery. The operation of the control system directly affects the resource of batteries. Modernization of existing control systems is one of the ways to increase the total life of batteries and slow down the process of their degradation. The first chapter presents an analysis of modern lithium-based battery types and their characteristics. An overview of equivalent circuit models of battery packs is provided. The structural features and applications of battery packs in electric transport and stationary energy storage systems are analyzed. The design and functions of battery management systems are examined. A classification and comparative analysis of battery balancing methods are conducted. The second chapter analyzes the causes of battery degradation. An evaluation of the average daily mileage of electric vehicles is provided. Studies presenting experimental and calculated values of battery lifespan dependence on depth of discharge and charge level range are considered. Estimated values of potential battery lifespan extension through the selection of an optimal partial cycling strategy are presented. Possible solutions for implementing an intelligent partial cycle selection system within an electric vehicle battery management system are proposed. The third chapter discusses the topologies of active balancers based on DC-DC converters. An improved active balancer topology is proposed, suitable for multicell battery packs. Modeling of balancing time for various balancing methods in the improved active balancer topology is performed. Modeling possible DC-DC converters for use in the improved active balancer topology is conducted, providing justification for selecting a specific DC-DC converter type in further research. The fourth chapter presents the design and printed circuit board (PCB) layout for a prototype of an active balancer with an improved topology for multicell battery packs. The prototype is assembled and integrated into an electric vehicle battery pack. An experimental study is conducted to evaluate the potential increase in battery lifespan due to the use of the improved active balancer. Keywords: battery, battery management system, efficiency, electric vehicle, hybrid power storage, charger, current source, active balancing, control system, power converter, inverter, control pulses, fault diagnosis, transistor switching, power loss.