Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (5): 1641-1649.doi: 10.19799/j.cnki.2095-4239.2021.0623

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

Combined CNN-LSTM and GRU based health feature parameters for lithium-ion batteries SOH estimation

Yanwen DAI(), Aiqing YU   

  1. College of Electrical Engineering, Shanghai University of Electric Power, Shanghai 200090, China
  • Received:2021-11-23 Revised:2021-12-08 Online:2022-05-05 Published:2022-05-07
  • Contact: Yanwen DAI E-mail:1209742263@ qq.com

Abstract:

The State of Health (SOH) of lithium batteries is a key parameter to characterize the actual useful life. SOH is not directly measurable, and a combined CNN-LSTM and GRU estimation method based on health feature parameters is proposed to further improve the accuracy of SOH estimation. Firstly, the health feature parameters are initially selected from the Li-ion battery charging curve, and the health features are extracted by Spearman correlation coefficient. Secondly, Convolutional Neural Network (CNN) is used to extract local features of health features and Long Short-Term Memory (LSTM) to mine data time series features to construct a CNN-LSTM fusion neural network. Subsequently, the CNN-LSTM and the Gated Recurrent Unit (GRU) are combined to form a combined SOH estimation model by adaptive weighting factors. Finally, the validation is based on the NASA lithium battery dataset 5, 6, 7, and 18 battery parameters. The experimental results show that the estimation accuracy of the proposed combined model is better than that of the single model, and the estimation error is further reduced.

Key words: lithium-ion battery, state of health, health feature, CNN-LSTM, GRU

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