Design and Optimization of Air-Cooled Structure in Lithium-Ion Battery Pack

This paper focuses on the thermal management of lithium-ion battery packs. Firstly, a square-shaped lithium iron phosphate/carbon power battery is selected, and a battery pack composed of 12 series-connected modules is constructed, adopting a parallel ventilation and forced air-cooling mechanism. Through orthogonal experimental design, the decreasing range of the battery pack spacing <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta \mathrm{L}$</tex>, the inclination angles of the upper and lower collector plates θu and θ1 are selected as factors, each with three levels. Simulation calculations are carried out using FLUENT software in combination with the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{k}-\epsilon$</tex> turbulence model and specific boundary conditions. In terms of the design of the heat dissipation system, goals in thermodynamics, fluid dynamics, and structural analysis are proposed, and the finite-element model of the heat dissipation system is parameterized. Through CFD numerical calculations, the standard <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{k}-\epsilon$</tex> model is selected, and the analysis is based on equations such as energy, continuity, and momentum equations. Meanwhile, a surrogate model is developed. After comparison, the Kriging model is selected, and the impacts of transverse and longitudinal pitches on heat dissipation and pressure drop are analyzed. Finally, a multi-objective optimization mathematical model is established based on the air-cooled BTMS. Taking the 7-fin model as an example, different schemes are obtained through optimization by the multi-objective genetic algorithm. For example, Scheme 1 reduces the average battery temperature, the standard deviation of temperature, and the system pressure drop while increasing the volume of the cooling model. This paper provides a comprehensive study and reference for the optimization of lithium-ion battery pack thermal management.