In-situ thermal simulation analysis method of battery cell in lithium ion battery pack system

Abstract

The invention discloses an in-situ thermal simulation analysis method of a battery cell in a lithium ion battery pack system. The in-situ thermal simulation analysis method comprises the following steps: 1, establishing a thermal simulation analysis model of the lithium ion battery pack system and realizing numerical calculation; 2, extracting boundary conditions required by the battery cell and structural entity and stimulation around the battery cell aiming at the thermal simulation analysis model of the lithium ion battery pack system and calculated result of the model; 3, establishing a thermal simulation model of the battery cell, and using extracted heat transfer condition information as loading and boundary conditions of the thermal simulation model of the battery cell, and meanwhile supplementing specific detail structure of the core inside the battery cell for thermal simulation analysis of the battery cell. Through the loading and boundary conditions in the thermal simulation model of the battery cell, supplementation of the specific detail structure of the core inside the battery cell is combined with remodeling means, so that abundant and accurate thermal property at the interior of the battery cell under specific working environment and working condition of the battery cell in a lithium ion battery pack system can be furthest given out.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to an in-situ thermal simulation analysis method for battery cells in a lithium-ion battery pack system. Background technique [0002] As an energy storage element, batteries are widely used in several fields of the national economy and people's production and life. The cooling member is used as a lithium-ion battery pack system. During the use of the battery, it is inevitable to generate heat and cause the temperature to rise, which will cause physical and chemical changes inside the battery, and may affect the performance, service life and safety performance of the battery, especially in consumer electronics, electric vehicles, etc. Lithium-ion battery products and their group systems, which are widely used in industries such as lithium battery, backup power supply and power energy storage, have higher requirements on the temperature range and temperature uniformity...

AI Technical Summary

Problems solved by technology

However, the known battery computer thermal simulation methods are completely different and independent to the research of the battery cell and the lithium-ion battery pack system: for the battery cell, in order to obtain the specific thermal characteristics of the internal structure of the battery cell, it is necessary to establish As detailed as possible the structural details of the battery cell, and estimate the approximate working environment of the battery cell, and add the boundary conditions required for the thermal analysis of the battery cell, such as the ambient temperature and the convective heat transfer coefficient and heat flux between the cell and the environment or heat flux density, etc., but for the battery cells that are grouped into a lithium-ion battery pack system and work in specific occasions, due to the complexity of the structure, working conditions, and internal and external environments of the lithium-ion battery pack system, it is often impossible to simply pass the overall Estimate and accurately give the heat transfer information between a certain battery cell and the environment; while the thermal simulation method at the system level of lithium-ion battery packs mainly focuses on how to reasonably arrange the battery cells and how to optimize the cooling medium flow path Design and how to adjust the working parameters of the cooling system to control the temperature range of the lithium-ion battery pack system and improve the temperature uniformity among the cells, but limited by the complexity of modeling and the number of meshes, the battery cells are often greatly simplified , and the physical parameters such as the density, specific heat, and thermal conductivity of various materials that make up the battery cell are mass-averaged, so the calculation results cannot provide rich and accurate thermal data for the battery cell in the lithium-ion battery pack system. feature

Especially when the capacity and size of a lithium-ion battery cell are large, there are dozens or even hundreds of layers of positive and negative electrodes and separators inside the battery, and there are also large differences in the physical parameters of various materials. There is a large temperature difference between the pole piece inside the process battery and the surface of the battery case, and the calculation results of the thermal simulation analysis of the battery pack system based on the simplified modeling of the battery cell cannot simulate the thermal characteristics inside the battery well.

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