CN-121997602-A - Three-dimensional electrochemical-thermal coupling simulation system for internal short circuit of lithium metal battery

CN121997602ACN 121997602 ACN121997602 ACN 121997602ACN-121997602-A

Abstract

The invention discloses a three-dimensional electrochemical-thermal coupling simulation system for internal short circuit of a lithium metal battery, and belongs to the technical field of simulation modeling and safety design of lithium ion batteries. Aiming at the problem that the multi-field coupling mechanism and the space-time evolution characteristic of lithium dendrite induced internal short circuit are difficult to reveal in the prior art, the invention establishes a high-fidelity simulation platform for electrochemical-thermal-short circuit multiple physical field bi-directional coupling by constructing a three-dimensional battery model integrating lithium dendrite geometry with definable size and position parameters. The system can accurately calculate current distribution, voltage drop, temperature field evolution and heat generation rules in the internal short circuit process, simulate different short circuit scenes through parameterization setting, and realize quantitative comparison and risk research and judgment of internal short circuit characteristics. The invention provides an advanced tool for researching the internal short circuit mechanism of the lithium metal battery, obviously reduces the research and development cost and period, and has important guiding significance for improving the safety of the high-energy-density battery.

Inventors

JIANG WENJUAN
XU JING
MA ZENGSHENG
JIANG XIAOHUA

Assignees

湘潭大学
郴江实验室
湖南沃尔顿动力科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260128

Claims (7)

1. A three-dimensional electrochemical-thermal coupling simulation system for internal short-circuiting of a lithium metal battery, the three-dimensional electrochemical-thermal coupling simulation system comprising: The method comprises the steps of establishing a three-dimensional geometric model based on sample parameters of a lithium metal battery to be detected, wherein the three-dimensional geometric model comprises a positive electrode, a negative electrode, a diaphragm and a current collector of the battery; A lithium dendrite geometry embedded in the three-dimensional geometric model and used for simulating a physical short contact, wherein the radius and the spatial position of the lithium dendrite geometry are definable parameters; the electrochemical-thermal coupling calculation module is used for coupling calculation of the following processes: The electrochemical process comprises the steps of calculating the voltage and current distribution and electrochemical heat generation of the lithium metal battery to be measured; calculating the temperature field time-space evolution of the lithium metal battery driven by the electrochemical heat generation and the internal short circuit ohmic heat; The short circuit feedback process is to feed back the electrochemical parameters inside the lithium metal battery changed by temperature change to the electrochemical process in real time, and feed back the internal short circuit resistor and the heat generated by the internal short circuit resistor to the electrochemical process and the thermal process; The three-dimensional electrochemical-thermal coupling simulation system simulates and outputs the change data of battery voltage, current density, temperature field and heat generation power under different internal short circuit scenes by changing the radius and position parameters of the lithium dendrite geometry, and is used for analyzing the internal short circuit characteristics and guiding the safety design of the battery.
2. The three-dimensional electrochemical-thermal coupling simulation system according to claim 1, wherein in the electrochemical-thermal coupling calculation module, the temperature change affects electrochemical reaction kinetic parameters in real time through an Arrhenius relationship, so that bidirectional coupling of a thermal field and an electrochemical field is realized.
3. The three-dimensional electrochemical-thermal coupling simulation system of claim 1, wherein the radius parameter of the lithium dendrite geometry ranges from 50 μm to 150 μm and the positional parameter is selected from one of a plurality of preset positions within the cell plane.
4. The three-dimensional electrochemical-thermal coupling simulation system according to claim 1, wherein the parameters of the three-dimensional geometric model and the electrochemical-thermal coupling calculation module are initialized and calibrated, and the data comprises one or more of geometric parameters, solid/liquid phase electrical conductivity, lithium ion diffusion coefficient, reaction rate constant, specific heat capacity and thermal conductivity based on data obtained by performing electrochemical testing and thermal testing on the actual lithium metal battery sample to be tested, the electrode sample and the material sample.
5. The three-dimensional electrochemical-thermal coupling simulation system according to claim 1, wherein when the target area containing the lithium dendrite geometry is subjected to grid division, the grid division strategy is to perform uniform grid division on the contact surfaces of the lithium dendrite geometry and the positive electrode and the negative electrode, and then perform free tetrahedral grid refinement treatment on the whole target area.
6. A method for simulating short-circuit behavior in a lithium battery by using the three-dimensional electrochemical-thermal coupling simulation system according to any one of claims 1 to 5, comprising the following steps: Step 1, obtaining physical and chemical parameters of a real lithium battery sample, and carrying out parameter initialization processing on the three-dimensional electrochemical-thermal coupling simulation system according to the physical and chemical parameters; Step 2, defining initial radius and initial space position parameters of lithium dendrite geometry in the three-dimensional electrochemical-thermal coupling simulation system, and operating the simulation system to obtain simulation data in an initial internal short circuit scene; step 3, changing radius and/or space position parameters of the lithium dendrite geometry, and operating a simulation system to obtain simulation data of at least one changed internal short circuit scene; and 4, comparing and analyzing the simulation data obtained in the step 2 and the step 3, and evaluating the risk level of internal short circuit caused by the lithium dendrite geometry under different parameters.
7. A method for the safe design of a lithium battery, characterized in that the lithium battery is optimized with respect to the risk level and parameters obtained according to the method of claim 6.

Description

Three-dimensional electrochemical-thermal coupling simulation system for internal short circuit of lithium metal battery Technical Field The invention relates to the field of simulation modeling of lithium ion batteries, in particular to a three-dimensional electrochemical-thermal coupling simulation system for internal short circuit of a lithium metal battery. Background Energy is a core driving force for national economic development, and is closely related to social operation and daily life. In recent years, development and utilization of clean renewable energy have rapidly progressed, gradually reducing the dependence on traditional fossil fuels. The lithium ion battery has the advantages of high energy density, long cycle life, high safety and the like, becomes one of the most important secondary energy storage systems, and is widely applied to the fields of new energy automobiles, small unmanned aerial vehicles, aerospace, large energy storage stations and the like. However, the energy density of the commercial lithium ion battery gradually approaches the theoretical upper limit of the embedded electrode material (such as a graphite cathode), and the energy density is further greatly improved, so that the innovation of the system level is needed. Lithium metal anodes are considered to be one of the key materials for the realization of next generation high energy density battery systems due to their extremely high theoretical specific capacity (mAh/g, about 10 times that of graphite) and lower electrochemical potential (-3.04V vs. Standard hydrogen electrode). The energy density of lithium metal batteries is expected to exceed 400 Wh/kg when matched to high capacity anodes such as lithium-rich manganese-based or nickel-cobalt-manganese ternary materials. Nevertheless, practical application of lithium metal batteries still faces serious challenges, mainly reflected in both poor cycling stability and outstanding safety issues. In the cycling process of the battery, uneven deposition is easy to occur on the surface of lithium metal lithium to form lithium dendrite, the continuous growth of the lithium dendrite can puncture a diaphragm to cause short circuit in the battery, and meanwhile, the precipitated lithium and electrolyte side reaction generate dead lithium to cause rapid capacity decay and coulomb efficiency reduction. Internal short circuit caused by lithium dendrite is a common cause of thermal runaway, seriously threatens the safety of a battery system, and has become a primary technical obstacle for restricting the commercial application of lithium metal batteries. At present, research on lithium dendrite and internal short circuit behaviors still highly depends on experimental means, and the method has the limitations of long test period, high cost, strong destructiveness, difficulty in observing internal reaction and thermal evolution in real time and the like. The traditional experimental method can not fully reveal the multi-field coupling mechanism and the time-space evolution characteristic in the internal short circuit process, and restricts the deep understanding of the failure mechanism of the battery and the establishment of the safety design criterion. Although some simulation models are used for battery research, most of the simulation models are limited to a single physical field or a simplified two-dimensional structure, and it is difficult to truly reflect internal short circuits induced by lithium dendrites and complex electrochemical-thermal coupling behaviors caused by the internal short circuits. Disclosure of Invention Aiming at the defects of the existing experimental means in revealing an internal short circuit multi-field coupling mechanism and space-time evolution behavior and the limitations of the existing simulation model in multidimensional coupling and geometric reality, the invention provides a three-dimensional electrochemical-thermal coupling simulation method for the internal short circuit behavior of a lithium metal battery. The system truly simulates an internal short-circuit process of a positive electrode and a negative electrode caused by piercing a diaphragm by a lithium dendrite by constructing a three-dimensional battery model of a lithium dendrite structure capable of defining geometric and position parameters, calculates and analyzes dynamic changes of key physical quantities such as electrode current density distribution, voltage change, temperature field evolution, internal heat generation and the like in the internal short-circuit occurrence process based on an electrochemical-thermal-short circuit multiple coupling mechanism, and realizes quantitative comparison and danger grade assessment of different internal short-circuit scenes by flexibly setting radius and spatial position parameters of the lithium dendrite. The invention provides a high-efficiency and reliable digital tool for the research of the internal short-circuit behavior of the lithiu