A New Method For Estimating The Remaining Capacity Of Battery

Battery is a kind of energy storage device that has been widely used in social production and people’s life. But the performance of the system is affected by the inequality, charge and discharge control method, working environment and other factors, which often cause the battery not to reach the design requirements, and these difficulties have a direct effect on estimating the remaining capacity of battery. So this thesis aims to study on how to accurately estimate the remaining capacity of battery, summary the conventional method and propose a new method after making important improvements, in order to realize the on-line estimation of remaining capacity of battery.The thesis uses the lithium iron phosphate battery as the object of study, summarizes the structure and working principle, analyses and studies the battery voltage, charge and discharge current, internal resistance, capacity, temperature etc. We find that battery internal resistance and voltage rise rate become larger as cycles of charge and discharge increases, and then put forward the battery health factor to characterize the change of battery health status. We have done very incisive analysis about the parameters of the model.We design a reasonable experimental platform to carry out a large number of charging and discharging experiments, record the parameters of the lithium iron phosphate battery. The experimental data are analyzed and tackled and the parameters of the model have been determined, then the on-line estimation model of the lithium iron phosphate battery was established. Experiments show that the method has high estimation accuracy. The accuracy is still good when the battery is aging which makes it much more adaptive to engineering application.