Cooling performance of 18650 lithium-ion battery module using Al2O3-GO hybrid and mono nanofluids: A numerical study with experimental validation

Lithium-ion batteries (LIBs) are increasingly favoured in electric vehicles due to their large capacity, high power, and extended driving range. However, significant heat generation during operation poses challenges for efficient battery thermal management systems (BTMS). This study presents a numerical investigation of a BTMS using a mini-channel cooling block with water and Al 2 O 3 -GO-based mono and hybrid nanofluids. The impact of nanoparticle concentration, fluid velocity, and current discharge rate on the thermal performance of cylindrical 18650 LIBs were analyzed using computational fluid dynamics (CFD). Thermal conductivity and dynamic viscosity of the Al 2 O 3 -GO nanofluids were experimentally evaluated. A novel cooling block featuring 5 mm diameter circular channels was designed and validated against experimental data, showing a maximum deviation of 0.26 °C. The results demonstrated significant temperature uniformity across LIB cells, with the hybrid nanofluid at 1 % volume concentration enhancing thermal conductivity by 42.5 % and reducing LIB temperature by 7.47 %. Increasing fluid velocity from 0.1 m/s to 0.3 m/s further improved cooling by 7.53 %. The study concluded that Al 2 O 3 -GO hybrid nanofluids are highly effective for BTMS, even under high current discharge rates, due to their enhanced heat transfer properties.