Advancement of lithium-ion battery cells voltage equalization techniques: A review
Document Type
Article
Publication Date
12-1-2020
Abstract
Recently, the use of electric batteries has reached great heights due to the invention of electric vehicles (EVs). Many lithium-ion battery cells are usually connected in series to meet the voltage requirements. The voltages of the entire series-connected battery cells in a battery pack should be equal. However, such result is impossible due to some unavoidable reasons in real life. Unbalanced battery cell voltages can reduce storage capacities and may cause explosions or fires in the worst case which is a major obstacle for safe and optimum operations of battery-driven appliances, such as EVs. Therefore, battery cell voltage equalizations have become an important research topic. Many studies have been conducted to develop and improve techniques to equalize battery cell voltages by incorporating various remarkable features. This study makes a comprehensive and systematic review of these cell equalization techniques. The importance and research prospect of battery cell voltage equalizers are discussed. A critical analysis of recent techniques, particularly on construction, operation, and control strategy of equalization circuits, is also presented. Moreover, recent studies are compared based on circuit designs, sizes, costs, complexities, system efficiencies, applications, control strategies, balancing speeds, and voltage/current stresses of different equalizers. Commonly used two different types of control strategies/algorithms in software system of battery cell equalizers are briefly described. The recent research trend of different equalizers is also discussed in detail. Simulation results of few equalization approaches and performance evaluation techniques are analyzed.
Keywords
Lithium-ion battery, Cell, Voltage equalization circuits, Control strategy, Electric vehicle (EV), Battery management system (BMS)
Divisions
fsktm,sch_ecs
Funders
Fundamental Research Grant Scheme (FRGS/1/2018/TK07/UM/02/4),Fundamental Research Grant Scheme (FP0952018A),NICOP research (N62909-18-1-2030),NICOP research (IF011-2018)
Publication Title
Renewable and Sustainable Energy Reviews
Volume
134
Publisher
Elsevier
Publisher Location
THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND