Synergistic effects of Fibonacci-inspired turbulators and hybrid nanofluids on thermal regulation in Li-ion battery packs

This study introduces a bio-inspired liquid cooling framework for prismatic Li-ion batteries by combining a Fibonacci spiral turbulator with a hybrid Al2O3–TiO2/water nanofluid. The logarithmic spiral geometry induces structured vortex flow and strong radial and axial momentum coupling, thereby intensifying fluid mixing and heat transfer. Three configurations (smooth channel, parallel flow, and alternating counterflow) were numerically analyzed under transient 2C discharge conditions using a validated numerical model with temperature-dependent hybrid nanofluid properties. Results reveal that incorporating the Fibonacci turbulator decreases the maximum cell temperature (Tmax) by around 0.83 K, reduces the temperature difference (ΔT) by up to 23% in Row 3, and lowers total entropy generation by 18 % compared to the baseline channel, with only a 2.8-fold increase in pressure drop. The hybrid nanofluid further enhances thermal conductivity and maintains uniform cooling without excessive pumping power. The synergistic effects of the Fibonacci-inspired turbulence and hybrid nanofluid improve convective uniformity, minimize thermodynamic irreversibility, and ensure efficient thermal regulation for high-density modules in electric vehicles.