Method and device for establishing regression model of electrochemical characteristic impedance of lithium battery

Abstract

The invention relates to a method and device for establishing a regression model of electrochemical characteristic impedance of a lithium battery. The method comprises the steps: obtaining an electrochemical impedance spectrum of a solid-liquid mixed electrolyte lithium battery based on different temperatures and SOC conditions; describing the characteristic impedance of the solid-liquid mixed electrolyte lithium battery electrode process dynamics, and selecting characteristic points from a Nyquist graph obtained after a electrochemical impedance spectroscopy test for analysis, wherein the positions and meanings of the characteristic points are partially changed along with the change of the battery system; and determining a nonlinear relationship between the temperature of the characteristic impedance of the solid-liquid mixed electrolyte lithium battery and the SOC according to the characteristic points to obtain a nonlinear regression model. According to the invention, comprehensive tests are designed, a selection method of the EIS characteristic impedance is given, an Arrhenius regression equation that the battery characteristic impedance changes along with the temperature and a polynomial regression equation that the battery characteristic impedance changes along with the SOC are established, and then the EIS characteristic impedance can be accurately regressed under different temperatures and SOC conditions.

Description

technical field [0001] The invention belongs to the technical field of battery management, and in particular relates to a method and device for establishing a regression model of the electrochemical characteristic impedance of a lithium battery. Background technique [0002] The internal mechanism of solid–liquid electrolyte lithium-ion battery (SLELB) can be characterized and distinguished by the method of Electrochemical Impedance Spectroscopy (EIS). Since its inception, EIS technology has been used for the study of full and half cells of various material types. In addition, EIS is also applied to the various processes of the internal reaction of the battery, such as the formation of a solid electrolyte interphase film (Solid Electrolyte Interphase, SEI), and the detailed study of the charge transfer process. In terms of various conditions affecting battery characteristics, EIS is also used in the study of battery capacity and impedance changes under different SOC, temper...

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Problems solved by technology

[0004] In view of this, the purpose of the present invention is to overcome the deficiencies in the prior art, to provide a method and device for establishing a regression model of the electrochemical characteristic impedance of a lithium battery, to solve the problem of SLELB research with large-scale commercialization prospects in the prior art. missing question

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