Thermal model modeling method for lithium ion battery pack based on air-cooling heat dissipating mode

Abstract

The invention relates to a thermal model modeling method for a lithium ion battery pack based on an air-cooling heat dissipating mode, and belongs to the technical field of batteries. According to the purpose, the thermal model modeling method for the lithium ion battery pack based on the air-cooling heat dissipating mode considers battery internal resistance and heat exchange coefficient time-varying condition, ensures model precision and reduces model solution difficulty. According to an energy conservation equation of the lithium ion battery pack, battery internal resistance data within the temperature range of 25-45 DEG C is fitted to obtain a linear function relational expression between the battery internal resistance and battery temperature, and finally a heat model of the monomer lithium ion battery is finally obtained. The defects that analytical solution cannot be obtained from an existing battery pack heat model, model accuracy is low, and the number of variables to be solved is large are overcome. The battery internal resistance and the heat exchange coefficient time-varying condition are considered, the analytical solution of the battery pack temperature can be obtained, model accuracy is ensured, the model solution difficulty is reduced, the number of variables to be solved is reduced, and a theoretical basis is provided for online estimating temperature of the lithium ion battery pack.

Description

technical field [0001] The invention belongs to the technical field of thermal management of power batteries of electric vehicles. Background technique [0002] During the driving process of electric vehicles, the power battery pack continues to discharge, especially in acceleration, climbing and other working conditions, it will frequently discharge large currents. During the discharge process, an electrochemical reaction will occur inside the battery pack to generate heat rapidly and the temperature rises sharply. Excessively high temperature will lead to a decrease in battery life and capacity, and even cause the battery pack to burn. Therefore, designing an effective battery thermal management system to dissipate heat and control the temperature of the battery pack is of great significance to the efficient and stable driving of electric vehicles. At present, the electric vehicle battery thermal management system generally adopts the air-cooled heat dissipation method. C...

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Problems solved by technology

The current concentrated mass thermal model of lithium-ion batteries ignores the influence of battery internal resistance on battery heat generation due to temperature changes, and the heat dissipation capacity of batteries is affected by environmental factors, and the model accuracy is low.

In the existing lumped mass thermal model of lithium-ion battery packs based on air-cooled heat dissipation, in order to obtain the maximum temperature and maximum temperature difference of the battery pack, it is necessary to measure or solve the air fluid temperature at each position in the cooling channel of the battery pack, and establish the thermal parameters of all batteries. model and solve it, the amount of calculation is large and the calculation process is complicated

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