CN-121983157-A - High-nickel ternary battery thermal runaway reaction kinetic parameter identification method

CN121983157ACN 121983157 ACN121983157 ACN 121983157ACN-121983157-A

Abstract

The invention discloses a method for identifying the thermal runaway reaction kinetic parameters of a high-nickel ternary battery based on DSC multi-exothermic-peak heat flow curves, which is characterized in that a chemical reaction kinetic model is established, and the identification of the thermal runaway reaction kinetic parameters of the high-nickel ternary battery is realized by applying a Kissinger equation and a particle swarm optimization algorithm based on DSC multi-peak heat flow curves under different temperature rising rates. The technical scheme method can provide necessary reaction kinetic parameters for thermal runaway modeling of the high-nickel ternary battery, has stronger global searching capability compared with the traditional genetic algorithm, realizes decoupling of thermal contributions among different reactions of battery materials in the thermal runaway process, can research improvement means aiming at high-heat-generation reaction among materials, and reduces the risk of thermal runaway of the high-nickel ternary battery.

Inventors

SUN BINGXIANG
XU CHENGRONG
ZHU XIYAN
ZHOU XINGZHEN
ZHANG XUBO
ZHANG KAI

Assignees

北京交通大学

Dates

Publication Date: 20260505
Application Date: 20260114

Claims (5)

1. The method for identifying the kinetic parameters of the thermal runaway reaction of the high-nickel ternary battery is characterized by comprising the following steps of: S1, disassembling a battery in a glove box to obtain positive and negative active substances of the battery, preparing single-component and multi-component samples of the battery, and performing DSC (differential scanning calorimetry) test to obtain heat flow curves of battery materials at different temperature rise rates; s2, establishing a chemical reaction dynamics model, and identifying the activation energy by using a Kissinger equation And forward factor Kinetic parameters of multiple exothermic peaks of two heat source samples; s3, fitting and identifying the reaction series m, the reaction series n and the enthalpy by using a particle swarm optimization algorithm And other kinetic parameters are equal, and the quantitative splitting of the heat contribution of the thermal runaway multi-exothermic reaction is realized through the fitting result of the heat flow curve of the main heat source.
2. The method for identifying the thermal runaway reaction kinetic parameters of the high-nickel ternary battery according to claim 1, wherein the specific steps of the step S1 are as follows: s11, disassembling the full-state battery in a glove box, obtaining a battery anode and cathode material and a diaphragm, and grinding; S12, preparing 3 single-component crucible samples of anode active substances, cathode active substances and electrolyte in a glove box, and 4 multi-component crucible samples of anode active substances, electrolyte, anode active substances, electrolyte, wherein the mass ratio of each component in the multi-component crucible samples is the mass ratio of a primary cell, and 7 groups of samples are arranged in the glove box DSC test is carried out at the heating rate to obtain a heat flow curve, and the first two samples which meet the requirement that the number of exothermic peaks is more than or equal to 4 and the heating value ranks all samples are used as multimodal main heat source samples respectively at DSC test is carried out at the temperature rising rate, and the heat flow curves at different temperature rising rates are obtained.
3. The method for identifying the thermal runaway reaction kinetic parameters of the high-nickel ternary battery according to claim 1, wherein the specific steps of the step S2 are as follows: s21, establishing a chemical reaction dynamics model and a heat generation model to describe exothermic behaviors of the battery material, namely ; ; ; ; In the formula, In order to achieve a chemical reaction rate, For a normalized concentration of reactant x, As a forward-direction factor, the forward-direction factor, In order for the activation energy to be sufficient, In order to achieve a molar gas constant, In the case of a thermodynamic temperature of the material, As a function of the concentration of the liquid, For the number of reaction stages, In order to react with the amount of heat released, In order to achieve the quality of the reactants, Is the reaction enthalpy; S22, identifying the activation energy of multiple reactions by using a Kissinger equation based on DSC multi-peak main heat source heat flow curves under different temperature rise rates And forward factor A, i.e ; In the formula, For the rate of temperature rise in the DSC test, For the peak temperature of the exothermic peak, u is the experimental number of DSC tests with different temperature rising rates, and is determined by The slope of the middle fitting straight line is calculated to obtain the activation energy of the exothermic reaction By the following constitution The intercept of the middle fitting line is calculated to yield the forward factor a.
4. The method for identifying the kinetic parameters of the thermal runaway reaction of the high-nickel ternary battery according to claim 1, wherein the step S3 is characterized in that the particle swarm optimization algorithm is applied to the reaction series m, the reaction series n and the enthalpy of other kinetic parameters Performing optimization fitting, wherein the fitness function is DSC heat flow curve root mean square error under different temperature rise rates, namely 。
5. The method for identifying the thermal runaway reaction kinetic parameters of the high-nickel ternary battery according to claim 1, wherein the high-nickel ternary battery is a ternary battery with nickel content higher than 50% such as NCM532, NCM622, NCM811 and the like.

Description

High-nickel ternary battery thermal runaway reaction kinetic parameter identification method Technical Field The invention belongs to the field of lithium ion battery safety, and particularly relates to a method for identifying dynamic parameters of thermal runaway reaction of a high-nickel ternary battery based on DSC (differential scanning calorimetry) multi-exothermic peak heat flow curve. Background The high-nickel ternary (NCM) positive electrode material is widely applied to electric automobiles and energy storage batteries due to the advantages of excellent electrochemical performance, long cycle life and the like. However, the high-nickel ternary cathode material can effectively improve the energy density of the battery, and simultaneously can also cause the reduction of the thermal stability of the battery and increase the risk of thermal runaway. Therefore, research on the thermal runaway mechanism of the high-nickel ternary battery and establishment of an accurate mathematical model to predict the thermal runaway behavior of the battery are important bases for advancing the safety design of the high-nickel ternary battery. Prior studies have shown that the thermal runaway process of lithium ion batteries generally undergoes several successive exothermic stages, typical reaction paths include SEI film decomposition, side reactions between the negative electrode and the electrolyte, separator melting and structural failure, thermal decomposition of the positive electrode material, electrolyte decomposition reaction, binder pyrolysis, and combustion of the electrolyte. The chemical kinetics analysis based on Arrhenius equation can obtain the kinetic parameters (such as activation energy and frequency factor) of the reactions, and further build a thermal runaway model to predict the thermal runaway behavior of the battery. The current research method is to obtain heat flow curves under different temperature rising rates through DSC battery component testing, establish a kinetic model and combine a Kissinger method and a genetic algorithm to identify kinetic parameters. However, the DSC heat flow curve of the high-nickel ternary positive electrode material often shows a multi-exothermic-peak overlapping mode, and the genetic algorithm has the problems of low convergence speed, easy sinking into local optimum and the like when fitting the multi-exothermic-peak DSC heat flow curve, and the fitting effect is poor. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a method for identifying the dynamic parameters of the thermal runaway reaction of a high-nickel ternary battery based on a DSC multi-exothermic-peak heat flow curve, which solves the problems that the convergence rate is slow and the local optimum is easy to fall into when the DSC multi-exothermic-peak heat flow curve of the high-nickel ternary battery is fitted by the traditional genetic algorithm, and specifically comprises the following steps: S1, disassembling a battery in a glove box to obtain positive and negative active substances of the battery, preparing single-component and multi-component samples of the battery, and performing DSC (differential scanning calorimetry) test to obtain heat flow curves of battery materials at different temperature rise rates; S2, establishing a chemical reaction dynamics model, and identifying the activation energy by using a Kissinger equation And forward factorKinetic parameters of multiple exothermic peaks of two heat source samples; s3, fitting and identifying the reaction series m, the reaction series n and the enthalpy by using a particle swarm optimization algorithm And other kinetic parameters are equal, and the quantitative splitting of the heat contribution of the thermal runaway multi-exothermic reaction is realized through the fitting result of the heat flow curve of the main heat source. Further, the specific steps of step S1 are as follows: s11, disassembling the full-state battery in a glove box, obtaining a battery anode and cathode material and a diaphragm, and grinding; S12, preparing 3 single-component crucible samples of anode active substances, cathode active substances and electrolyte in a glove box, and 4 multi-component crucible samples of anode active substances, electrolyte, anode active substances, electrolyte, wherein the mass ratio of each component in the multi-component crucible samples is the mass ratio of a primary cell, and 7 groups of samples are arranged in the glove box DSC test is carried out at the heating rate to obtain a heat flow curve, and the first two samples which meet the requirement that the number of exothermic peaks is more than or equal to 4 and the heating value ranks all samples are used as multimodal main heat source samples respectively atDSC test is carried out at the temperature rising rate, and the heat flow curves at different temperature rising rates are obtained. Further, the specific steps of