Electrochemical-thermal-mechanical coupling model of lithium ion battery and modeling method

Abstract

The invention relates to an electrochemical-thermal-mechanical coupling model of a lithium ion battery and a modeling method. Based on a classic electrochemical quasi-two-dimensional model of the lithium ion battery, heat generated by electrochemical reaction of the battery in use is introduced; meanwhile, a three-dimensional lumped parameter thermal model is adopted to simulate temperature changein the battery cycle process, a mechanical damage model of the battery in the whole life cycle is established to describe the influence of ion diffusion induced stress on the service life of the battery in the charging and discharging process of the battery, and a dynamic parameter compensation method is utilized to couple the models. The lithium ion battery electrochemical-thermal-mechanical coupling model generated by using the model building method can be used for estimating and predicting the monomer temperature of a battery thermal management system (BTM) and researching the physical property change and thermal runaway of the battery; a basis is provided for research on the performance evolution law of the lithium ion battery, and the method has important significance in slowing downbattery aging and prolonging the service life.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to an electrochemical-thermal-mechanical coupling model and a modeling method of a lithium ion battery. Background technique [0002] Lithium-ion batteries have been widely used in pure electric vehicles and hybrid vehicles due to their high energy density and good safety performance. The energy and power performance of lithium-ion batteries are extremely sensitive to temperature. [0003] When the temperature is low, it will seriously reduce the usable capacity and power of the battery, reduce the battery's charging acceptability, and reduce the service life; and when the temperature is too high, it is easy to cause the decomposition of the electrolyte, and the increase in the electronic conductivity caused by the dissolution of the surface active material will cause Increase the rate of self-discharge of the battery; coupled with the continuous growth and uneven dist...

AI Technical Summary

Problems solved by technology

However, due to the long life of lithium-ion batteries, the factors affecting the evolution of battery performance in actual use are complex, and the main mechanisms leading to battery aging in different environments and working conditions are often not exactly the same

Usually, the use of experimental means to study the evolution of the internal mechanism of the battery takes a long time and is costly

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