Reverse calculation method and device for internal thermal resistance parameter of lithium ion soft package battery

Abstract

The invention relates to the technical field of lithium ion battery thermal management, discloses a method and a device for reversely solving internal thermal resistance parameters of a lithium ion soft package battery, and aims to provide a key parameter estimation tool for accurately calculating the temperature of the lithium ion soft package battery. The method comprises the following steps of firstly, defining an internal thermal resistance parameter to be solved, and constructing a thermal resistance parameter reverse solving experiment device to implement a thermal induction experiment; secondly, establishing physical equations of heat generation, gas generation, heat transfer, expansion and the like, and fusing the physical equations into a soft package battery temperature evaluation model; thirdly, a reverse model of the internal thermal resistance parameters of the soft package battery being constructed, and the internal thermal resistance parameters of the battery being obtained based on test data and a physical model. Compared with the prior art, the thermal resistance parameter obtained by the method is suitable for the lithium ion soft package battery with the same electrolyte, and the application range is relatively large; based on experimental data and a physical model, thermal resistance parameters are calculated through a reverse solving technology, and precision is high; the method is clear in steps, easy to understand, simple in device, clear in definition and good in engineering practicability.

Description

technical field [0001] The invention relates to the technical field of thermal management of lithium-ion batteries, in particular to a method and device for reverse calculation of internal thermal resistance parameters of lithium-ion pouch batteries. Background technique [0002] Lithium-ion soft-pack batteries have been widely used in consumer electronic devices due to their advantages of high energy density and continuous cost reduction, and have gradually expanded to the fields of energy storage systems and power vehicles. However, safety issues caused by battery thermal runaway always exist. Under heat abuse conditions, a chemical exothermic reaction occurs inside the pouch battery; when the heat release rate exceeds the heat dissipation efficiency, the internal temperature rises to accelerate the exothermic reaction, resulting in continuous accumulation of heat and reaction gases inside the battery. Temperature or pressure reaching a critical value will trigger thermal...

AI Technical Summary

Problems solved by technology

Existing studies have shown that the thermal conductivity of gas-liquid mixtures is related to both temperature and pressure, and the theoretical calculation method of steady-state thermal conductivity is still controversial

However, under the condition of heat abuse, there is a dynamic process of drastic temperature and pressure changes inside the pouch battery, and it is more difficult to calculate the dynamic thermal conductivity of the gas-liquid mixture using theory.

On the other hand, limited by the packaging form and testing methods of pouch batteries, it is also very challenging to obtain the dynamic curve of the thermal conductivity of the gas-liquid mixture through experimental methods

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