Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (12): 4010-4021.doi: 10.19799/j.cnki.2095-4239.2022.0384

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

State of health estimation method for lithium-ion batteries based on principal component analysis and whale optimization algorithm-Elman model

Xudong LI(), Xiangwen ZHANG()   

  1. School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin 541004, Guangxi, China
  • Received:2022-07-08 Revised:2022-07-15 Online:2022-12-05 Published:2022-12-29
  • Contact: Xiangwen ZHANG E-mail:20082305098@mails.guet.edu.cn;zxw@guet.edu.cn

Abstract:

Accurate estimation state of health (SOH) of lithium-ion batteries is the key to ensuring the efficient, safe, and sustainable operation of electric vehicles. The accuracy of SOH estimation can be improved with a data-driven method. However, the accuracy of SOH estimation in this method is highly dependent on the selected feature and estimation model. The redundancy between features and the lack of generalization of the estimation model will affect the accurate estimation of battery SOH. According to principal component analysis and whale optimization algorithm (WOA)-Elman, a new SOH estimation method is proposed to reduce the redundancy of input features, increase the model's generalization, and improve the accuracy of SOH estimation. Firstly, the features highly related to the aging of lithium-ion batteries were extracted and selected from the charging process curve. Principal component analysis was used to decrease the dimension of features and reduce the redundancy between features. Then, the WOA method was used to optimize the initial weights and thresholds of the Elman model to establish the WOA-Elman model. The B01 battery was used to train the model while B02 and B03 batteries were used to verify the model. Simultaneously, comparing the commonly used long short-term memory neural network, support vector regression, extreme learning machine, and the unoptimized Elman model. The results show that the root-mean-square error of the WOA-Elman estimation model is 1.2113%. Finally, the SOH of the remaining two groups of batteries was estimated and verified by alternating test data of three groups of batteries as training sets, and the maximum root-mean-square deviation of the estimated results was only 0.1771%. Therefore, the proposed method can estimate battery SOH more accurately and perform better generalization.

Key words: lithium-ion battery, state of health estimation, principal component analysis, elman neural network, whale optimization algorithm

CLC Number: