Power lithium battery thermal model building method and system based on electrochemical mechanism

Abstract

The invention provides a power lithium battery thermal model building method and system based on an electrochemical mechanism, and relates to the technical field of lithium battery management of electric automobiles, and the method comprises the steps: S1, carrying out the discretization of a second-order partial differential heat conduction equation of a lithium ion battery based on a finite difference method, and building a thermal model of the lithium battery; s2, selecting a cylindrical lithium battery as an object for dynamic working condition testing, and obtaining experimental data including temperature, current, voltage and battery surface temperature; s3, identifying electrochemical parameters of the lithium battery based on an optimal parameter algorithm by adopting test data under a certain dynamic working condition so as to establish a battery thermal model; and S4, adopting testing data under other dynamic working conditions to verify the accuracy of the lithium battery thermal model. According to the method, the function of the thermal management system of the battery is realized, the reliability and the safety of the battery pack are improved, the calculation amount is greatly reduced while the model precision is ensured, and the method is suitable for batteries in any shape.

Description

technical field [0001] The invention relates to the technical field of lithium battery management of electric vehicles, in particular to a method and system for building a power lithium battery thermal model based on an electrochemical mechanism. Background technique [0002] As the electric vehicle market continues to increase the demand for the energy density of lithium batteries, the thermal safety of lithium batteries has also been exposed. During use, the temperature of the battery may become too high, or even thermal runaway may occur, causing smoke, fire or even explosion. Therefore, it is crucial to establish a thermal model that can accurately monitor the temperature distribution of the battery. [0003] The Chinese invention patent with the publication number CN109141685A discloses a method and device for calculating the heat generation rate of a battery. The method includes: 101. During the discharge process of the battery, measure and record the working voltage ...

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Problems solved by technology

[0004] At present, the thermal models of lithium batteries are mainly divided into three categories: thermal models based on internal mechanisms and thermal models based on equivalent circuits. Although thermal models based on internal mechanisms can accurately simulate the heat production law and internal temperature distribution of batteries, However, the model is too complex and the amount of calculation is too large to be applied in practice. The thermal model based on the equivalent circuit is too simple to accurately obtain the internal temperature distribution of the battery.

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