Journal of Electroanalytical Chemistry, p. 115488, 2021. DOI: 10.1016/j.jelechem.2021.115488

A Mathematical Method for Open-Circuit Potential Curve Acquisition for Lithium-Ion Batteries

Jufnu Li1,2,3, Ming Zhao2,4, Changsong Dai3, Zhenbo Wang3,4, and Michael Pecht5

1 School of Automotive Engineering, Harbin Institute of Technology, Weihai 264209, Shandong, China
2 Guangdong Guanghua Sci-Tech Co. Ltd., Shantou 515000, Guangdong, China
3 School of Chemical Engineering and Chemistry, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
4 Zhuhai Zhongli New Energy Sci-Tech Co.Ltd., Zhuhai 519000, Guangdong, China
5 Center for Advanced Life Cycle Engineering (CALCE), University of Maryland, College Park, MD, USA


A half-cell test is often used to obtain electrode potentials for lithium-ion batteries when using an electrochemical model to simulate terminal voltage, which needs a series of time-consuming processes. However, this method generally requires expensive electrochemical measuring equipment, reference electrodes, and a vacuum glove box. This study develops a mathematical method for open-circuit potential curve acquisition. With a known open-circuit potential of the positive electrode and full-cell open-circuit voltage approximately measured at a low discharge rate of 0.02C, an open-circuit potential curve of the negative electrode can be calculated. A mathematical expression incorporating hyperbolic tangent functions and exponential functions with central coordinate positions against different lithiation states is then selected to describe the negative open-circuit potential. Finally, a least squares fitting method is adopted to identify the unknown coefficients in the expression. Five types of batteries are then tested to assess the accuracy and robustness of the method.

This article is available online here and to CALCE Consortium Members for personal review.

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