CFD-Assisted BTMS Optimization for High-Energy-Density Cylindrical Lithium-Ion Cells

High-energy-density cylindrical lithium-ion batteries, such as 2170 cells, demand efficient thermal management to ensure safe operation, prolonged cycle life, and optimal performance. This study presents a computational fluid dynamics (CFD)-based optimization of a liquid-cooled Battery Thermal Management System (BTMS) incorporating novel triangular-shaped coolant passages positioned between three adjacent cells. The design enhances coolant–cell interaction, improves temperature uniformity, maintains a compact module geometry, and achieves a high volumetric packing efficiency (VPE) of 82.6%. Simulations were performed in ANSYS Fluent 2025 R1 under discharge rates of 1C, 2C, and 5C, with coolant velocities ranging from 0.005 to 0.05 m/s. Results indicate that the triangular channels effectively reduce maximum cell temperature, maintain near-zero temperature difference between cells due to symmetry, and limit pressure drop to below 90 Pa, while increasing the coolant–cell contact area per cell by 43%. These findings demonstrate that the proposed BTMS offers thermally stable, energy-efficient, and manufacturable battery modules suitable for next- generation electric vehicles.