Energy Storage Science and Technology ›› 2025, Vol. 14 ›› Issue (1): 346-357.doi: 10.19799/j.cnki.2095-4239.2024.0473

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

State of health interval estimation for lithium battery via Gaussian process regression with adaptive optimal combination Kernel function

Yingying LIU1(), Xiaoyuan ZHANG1(), Mengnan LIU1, junzhang SUN2, Yan ZHANG3   

  1. 1.College of Electrical Engineering, Henan University of Technology
    2.Henan United Chemical Energy Group Co. Ltd
    3.Henan Zhongchuang Hi Tech New Energy Technology Co. Ltd, Zhengzhou 450001, Henan, China
  • Received:2024-05-18 Revised:2024-09-28 Online:2025-01-28 Published:2025-02-25
  • Contact: Xiaoyuan ZHANG E-mail:3326845918@qq.com;freedon@haut.edu.cn

Abstract:

The degradation of lithium battery state of health (SOH) is to some extent a nonsmooth stochastic process, which makes most of the current point estimation machine learning approaches limited in practical applications. In recent years, Gaussian process regression (GPR), which is based on the Bayesian theory, has been widely used in lithium battery SOH interval estimation due to its ability to quantify uncertainty in the estimation results; however, the performance of GPR significantly depends on the selection of its kernel function. Current studies typically rely on empirically selecting a fixed single kernel function, which may not be suitable for diverse datasets. To address this limitation, this study introduces an SOH interval estimation method for lithium batteries based on an adaptive optimal combination of kernel functions in GPR. The proposed method first extracts multiple health factors from the battery's charge/discharge data and uses the Pearson correlation coefficient method to optimize six health factors that are strongly correlated with SOH as inputs to the model. Subsequently, with a set of seven commonly used kernel functions, new kernel function combinations were created by two-by-two random combinations. Cross-validation was then used to adaptively optimize the optimal kernel function combinations. The proposed approach was validated using three different datasets, and the results indicate its excellent performance in SOH interval estimation. For the three publicly available datasets, the average interval width index is within 0.0530, the average interval score is greater than -0.0004, and the root mean square error is less than 0.0181.

Key words: lithium-ion battery, state of health, Gaussian process regression, interval estimation, combined kernel function

CLC Number: