Abstract
Accurate state of charge estimation and robust cell equalization are vital in optimizing the battery management system and improving energy management in electric vehicles. In this paper, the passive balance control based equalization scheme is proposed using a combined dynamic battery model and the unscented Kalman filter based state of charge estimation. The lithium-ion battery is modeled with a 2nd order Thevenin equivalent circuit. The combined dynamic model of the lithium-ion battery, where the model parameters are estimated depending on the state of charge, and the unscented Kalman filter based state of charge, are used to improve the performance of the passive balance control based equalization. The experimental results verified the superiority of the combined dynamic battery model and the unscented Kalman filter algorithm with very tight error bounds. Furthermore, these results showed that the presented passive balance control based equalization scheme is suitable for the equalization of series-connected lithium-ion batteries.
Highlights
Conventional fossil fuel vehicles are emitting a considerable amount of CO2
This paper presented a State of Charge (SoC) based equalization scheme based on passive balance control (PBC)
A combined dynamic model of the Li-ion battery was proposed by using a second order Thevenin model, open circuit voltage (OCV), and coulomb counting (CC) method
Summary
Conventional fossil fuel vehicles are emitting a considerable amount of CO2. In response to the concern for the protection of environment, automotive industries proposed electrical vehicles (EVs) as a solution for conventional fossil fuel vehicles [1,2,3]. There are many methods to estimate the SoC of a Li-ion battery, methods such as coulomb counting (CC), open circuit voltage (OCV), neural network (NN), fuzzy logic, and Kalman filter based algorithms [12,13,14,15,16]. The accuracy of EKF based SoC estimation depends on the precision of the battery model and information of the system noise and covariance matrix [26,27,28]. To improve the cell equalization, the SoC based method is more suitable because SoC represents a comprehensive performance of the battery characteristic [37]. According to the combined dynamic battery model, UKF based SoC estimation is used to implement the equalization of Li-ion battery packs. In order to protect seriesconnected Li-ion cells from cell inconsistencies, passive balance control (PBC) is used with SoC based equalization
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
