Parameter obtaining method of single lithium ion full battery

Abstract

The invention provides a parameter obtaining method of a single lithium ion full battery, and belongs to the field of new energy research. The method comprises the following steps that 1) a mathematical electrochemical impedance spectrum model of the lithium ion battery is established; 2) an electrochemical impedance spectrum of the single lithium ion full battery to be measured is measured actually; and 3) according to the established mathematical model, parameters of the actually measured electrochemical impedance spectrum are identified according to frequency ranges, and anode and cathode parameters of the single lithium ion full battery to be measured are obtained. Aimed at the defect that parameters cannot be identified effectively when a present semi-battery model is used for a full battery, characteristics of the electrochemical impedance spectrum of the lithium ion battery are combined, a manner of parameter identification according to the frequency ranges is used, and anode and cathode model parameters of the lithium ion full battery can be obtained rapidly and accurately. The method of the invention can be used for gaining mechanism analysis, SOC estimation and life prediction of the lithium ion battery.

Description

technical field [0001] The invention relates to a parameter acquisition method of a lithium ion battery, in particular to a parameter acquisition method of a single lithium ion full battery, belonging to the field of new energy research. Background technique [0002] Lithium-ion batteries have outstanding advantages such as high voltage, high energy density, good cycle performance and no memory effect, and have been widely used. In the research of lithium-ion batteries, Electrochemical Impedance Spectroscopy (EIS) technology is widely used. Electrochemical Impedance Spectroscopy is also called AC Impedance Spectroscopy. The interface reaction, charge transfer, diffusion and other processes are effectively decoupled, and its measurement and analysis techniques are widely used in the description of battery characteristics, which can then analyze the battery state and improve battery preparation. EIS technology also provides a basis for judging the battery's health status asse...

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Problems solved by technology

However, this model is a half-cell model, which is mostly used in the research of half-cells and three-electrode lithium-ion batteries (with reference electrodes), while the current commercial lithium-ion batteries are mostly two-electrode full batteries (abbreviated as full batteries). If the model is used in a lithium-ion full battery, it is necessary to superimpose two models of the positive electrode and the negative electrode to obtain the full battery model. At this time, the model parameters are too many and coupled with each other, the identification time is long and the accuracy is very low, so the model is difficult to apply into a two-electrode Li-ion battery

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