Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (2): 673-678.doi: 10.19799/j.cnki.2095-4239.2021.0503

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

Fast estimation method for state-of-health of retired batteries based on electrochemical impedance spectroscopy and neural network

Mengmeng GENG1(), Maosong FAN1, Kai YANG1(), Guangjin ZHAO2, Zhen TAN1, Fei GAO1, Mingjie ZHANG1   

  1. 1.China Electric Power Research Institute, Beijing 100192, China
    2.State Grid Henan Electric Power Research Institute, Zhengzhou 450052, Henan, China
  • Received:2021-09-27 Revised:2021-10-14 Online:2022-02-05 Published:2022-02-08
  • Contact: Kai YANG E-mail:gengmengmeng@epri.sgcc.com.cn;ykbit@126.com

Abstract:

To improve the speed and accuracy of estimating the state-of-health (SOH) of decommissioned batteries, for retired prismatic lithium-iron-phosphate batteries of certain electric buses, eight batteries were selected to continue the cyclic aging experiment, and electrochemical impedance tests were conducted for different cycles. According to the impedance characteristics of lithium-ion batteries, the real part, imaginary part, and modulus at 300 Hz, 60 Hz, and 1 Hz were extracted as characteristic parameters, which reduced the test time from 10 min to a few seconds. Using characteristic parameters as input parameters, combined with BP neural network algorithm, we developed a fast estimation model of retired battery health based on electrochemical impedance and BP neural network and verified the model using 19 datasets that did not participate in model training. The average absolute percentage error of the verified sample's SOH estimate was 1.46%, and the root-mean-square error was 1.60%. The results show that the overall error is low. The method has high estimation accuracy and short test time, realizes rapid estimation of the health status of retired batteries, and is conducive for practical applications.

Key words: electrochemical impedance spectroscopy, BP neural network, retired battery, state-of-health

CLC Number: