Energy Storage Science and Technology ›› 2020, Vol. 9 ›› Issue (6): 1976-1981.doi: 10.19799/j.cnki.2095-4239.2020.0189

• Energy Storage Test: Methods and Evaluation • Previous Articles     Next Articles

Adaptive estimation method for full charge capacity of lithium battery

Jiang'an ZHANG1(), Hongbai YANG2, Zuohan ZHOU1   

  1. 1.Advanced Vocational Technical College, Shanghai University of Engineering Science, Shanghai 200437, China
    2.School of Science and Technology, Shanghai Open University, Shanghai 200433, China
  • Received:2020-05-23 Revised:2020-06-26 Online:2020-11-05 Published:2020-10-28

Abstract:

A full-battery capacity estimation method using the maximum chemical capacity of the lithium battery is proposed herein to solve the problems of slow update and low accuracy in the full-battery capacity estimation method based on the Coulomb integral in the existing lithium battery management system. During the charging process, the battery charging time constant is estimated according to the equivalent resistance-capacitance model of the lithium battery and the current sampling sequence. According to the charging time constant and the charging cut-off current, the virtual capacity in the constant voltage stage is then calculated by assuming that charging is started from the cut-off current until an infinite time. Meanwhile, the maximum chemical capacity of the lithium battery is calculated based on the discharge depth of the two selected relaxation states of the lithium battery and the charge capacity between these two states. Finally, the full charge capacity of the battery is calculated according to the approximate relationship among the full charge capacity, maximum chemical capacity, and virtual capacity. The experimental results show that the full charge capacity errors are less than 3% under different temperatures and health states. In other words, the proposed full charge capacity estimation method has high accuracy and strong adaptability and can meet the needs of the actual lithium battery management system. This method has the advantages of simple calculation and easy implementation and wide application prospects in various lithium battery management systems. This study explores and utilizes the internal relationship between the full charge and maximum chemical capacities, which provides a new method of estimating the state parameters of lithium batteries.

Key words: lithium battery, full charge capacity, resistance-capacitance model, adaptive estimation

CLC Number: