CFD-Based Thermal and Flow Optimization of a Z-Type Forced-Air Battery Thermal Management System for Prismatic LFP Cells

Abstract

This study presents a computational fluid dynamics (CFD) investigation using ANSYS Fluent to improve the thermal and flow performance of a Z-type parallel forced-air cooling Battery Thermal Management System (BTMS) for an eight-cell prismatic lithium iron phosphate (LFP) battery pack. Four design parameters are examined sequentially: inlet air velocity (3.0–5.0 m/s), tapered inlet-manifold height (3–20 mm), number of secondary outlets (0–8), and inter-cell gap width (2–5 mm). The effects of these parameters on the maximum cell temperature (T_max), maximum temperature difference (ΔT_max), inter-channel velocity distribution, and pressure drop are evaluated using a conjugate heat-transfer model. The results indicate that increasing inlet velocity enhances convective heat removal, while excessive velocity can aggravate flow maldistribution in a Z-type manifold. The study identifies 4.5 m/s as a favourable operating point in the reported sequential optimization, seven secondary outlets as an effective outlet configuration, and a 2 mm inter-cell gap as the best-performing gap among the configurations quantified in the final comparison. The results demonstrate that geometric optimization of a forced-air BTMS can improve thermal uniformity without changing the cooling medium, providing a practical approach for compact prismatic-cell battery packs. The numerical model is validated against published experimental temperature data, with the reported maximum deviations remaining within 8%. The study also documents the mesh, material properties, boundary conditions, and supplementary cell-temperature profiles used to support the parametric analysis.