A Research On Ultracapacitor Storage Management System

Although the great development of modern battery technology has been achieved,sometimes applications require both high energy density and great power density,while single type battery cannot satisfy the general condition,thus compound battery system is applied.To extend the lifespan and improve instantaneous charge and discharge ability of energy storage system,ultracapacitor is widespread applied as the power compensation in many hybrid propulsion systems for its large capacitance,high power density,quick charge and discharge ability,long circulation lifespan,etcetera.The continuous condition monitoring of cells to obtain the energy system state parameters such as SOC(state of charge),SOP(state of power),temperature is vitally important to ensure the safe and efficient charge-discharge cycle process of any energy storage system.As part of the hybrid energy storage system,power management system is also required for the ultracapacitor cell stacks.In consideration of the series-parallel connection of so many battery cells,identifying the parameters of each cell accurately and reliably is a major requisite to estimate the state of assembled battery pack.With the deep analysis of mechanism and thorough understanding of charge and discharge characteristics of ultracapacitor,a battery management system targeted ultracapacitor is designed to achieve accuracy,real-time measure of the voltage,current and temperature of the cell and battery pack,which is for accurate estimation of state parameters such as SOC,SOP,etcetera.Because over high charging voltage,prolonged high temperature,excessive large discharging current and inconsistencies in cells may cause negative effects to the ultracapacitor storage system,various state parameters of ultracapacitor cells are collected to ensure the storage system reliable and efficient operation through a long lifetime.Mature ICs are applied for the design to increase the reliability and integrated level of the battery management system.The system consists of hardware electric circuit and software procedure.Voltage,current and temperature acquisition circuit are included in the hardware,while the software covers the data acquisition program and communication program,etcetera.The printed-circuit board sample fulfilled the desired accuracy and reliability through a series of tests.