Energy Storage Science and Technology ›› 2024, Vol. 13 ›› Issue (9): 2995-3005.doi: 10.19799/j.cnki.2095-4239.2024.0465

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State-of-health estimation of lithium batteries based on polynomial feature extension of the CNN-transformer model

Yuan CHEN(), Siyuan ZHANG, Yujing CAI, Xiaohe HUANG, Yanzhong LIU   

  1. Anhui University School of Artificial Intelligence, Hefei 230601, Anhui, China
  • Received:2024-05-28 Revised:2024-07-04 Online:2024-09-28 Published:2024-09-20
  • Contact: Yuan CHEN E-mail:cumtjiangsucy@126.com

Abstract:

To enhance the accuracy of state-of-health (SOH) estimation for lithium-ion batteries, this study proposes a convolutional neural network (CNN)-transformer fusion model based on polynomial feature expansion. The model leverages the powerful local feature extraction capability of CNNs and the sequence processing ability of transformers. Key health factors, highly correlated with battery capacity, such as peak values of incremental capacity curves, corresponding voltages, areas, and charging time, were extracted and expanded using polynomial features. This expansion enhances the model's ability to handle nonlinearities in the input features. Principal component analysis was employed to reduce the dimensionality of the feature space, which aided in capturing adequate data information and reduced training time. The effectiveness and accuracy of the proposed fusion algorithm were validated using open-source datasets from the National Aeronautics and Space Administration (NASA) and the University of Maryland. Comparative analyses of SOH estimation were conducted for the CNN-transformer model with and without polynomial features and for single-model algorithms. The results indicate that the SOH estimation accuracy of the proposed model, compared to the CNN-transformer model without polynomial features, improved by 38.71%, 50.28%, 4.71%, and 17.58% for datasets B0005, B0006, B0007, and B0018, respectively.

Key words: lithium-ion battery, battery state of health prediction, principal component analysis, CNN-Transformer, incremental capacity analysis, polynomial features

CLC Number: