Determination of the Differential Capacity of Lithium-Ion Batteries by the Deconvolution of Electrochemical Impedance Spectra

Energies

Mengchao Yi¹  Dongxu Guo²  Geng Yang²  Guangjin Zhao³  Xuning Feng⁴  Xuebing Han⁴  Languang Lu⁴  Minggao Ouyang⁴ 

[1] College of Engineering, China Agricultural University, Beijing 100083, China;Department of Automation, Tsinghua University, Beijing 100084, China;State Grid Henan Electric Power Research Institute, Zhengzhou 450052, China;State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China;

关键词: lithium-ion battery;    electrochemical impedance spectroscopy;    distribution of relaxation times;    differential capacity;    joint estimation;    state-of-health evaluation;   

DOI  :  10.3390/en13040915

来源: DOAJ

【 摘 要 】

Electrochemical impedance spectroscopy (EIS) is a powerful tool for investigating electrochemical systems, such as lithium-ion batteries or fuel cells, given its high frequency resolution. The distribution of relaxation times (DRT) method offers a model-free approach for a deeper understanding of EIS data. However, in lithium-ion batteries, the differential capacity caused by diffusion processes is non-negligible and cannot be decomposed by the DRT method, which limits the applicability of the DRT method to lithium-ion batteries. In this study, a joint estimation method with Tikhonov regularization is proposed to estimate the differential capacity and the DRT simultaneously. Moreover, the equivalence of the differential capacity and the incremental capacity is proven. Different types of commercial lithium-ion batteries are tested to validate the joint estimation method and to verify the equivalence. The differential capacity is shown to be a promising approach to the evaluation of the state-of-health (SOH) of lithium-ion batteries based on its equivalence with the incremental capacity.

【 授权许可】

Unknown