Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (2): 689-694.doi: 10.19799/j.cnki.2095-4239.2020.0382

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

Estimation of SOH and remaining life of lithium batteries based on a combination model and long short-term memory

Weixia LIU1(), Xun TIAN1, Jiayong XIAO1, Wei CHANG2, Yuan LI2, Liang MAO2   

  1. 1.Beijing Electric Vehicle Automobile Co. Ltd. , Beijing 100176, China
    2.Shanghai CloudReady Technology Co. Ltd. , Shanghai 200030, China
  • Received:2020-11-26 Revised:2020-12-14 Online:2021-03-05 Published:2021-03-05
  • Contact: Weixia LIU E-mail:jueyun_idea@163.com

Abstract:

The traditional method of predicting the state of health (SOH) of a battery is generally based on historical data. Predicting the real-time state of a lithium battery or estimating its remaining service life is difficult. Aiming at the real-time prediction of battery SOH, we introduce a large amount of real-vehicle battery data (combined with machine learning and ampere-hour integration method to model and predict SOH) to process features and train data. On the basis of the model test results, this article proposes a real-time SOH hybrid prediction model combining the LightGBM and CatBoost algorithms. By verifying the hybrid model with two real vehicles as the carrier, the measured absolute average error of the real-time SOH prediction is 0.009. Our research intends to obtain the SOH attenuation curve to predict the remaining battery life. Therefore, we establish a long short-term memory (LSTM) neural network model to predict the future decay curve of battery SOH, characterized by the difference in SOH within a fixed time interval. This reduces the fluctuation of the difference and ensures that the data have similar distribution laws. By verifying the real-time monitoring data set provided by an original equipment manufacturer, the absolute average error of the future attenuation curve prediction is 0.021. The overall results show that the real-time SOH prediction model and the remaining life prediction model of the lithium battery studied in the article have high prediction accuracy. The battery user can better grasp the real-time status of the lithium battery and provide a basis for relevant decision making.

Key words: machine learning, SOH, combined model, LSTM

CLC Number: