Cooling lithium-ion batteries with silicon dioxide -water nanofluid: CFD analysis

Temperature is recognized to have a major impact on the safety, performance, and cycle life of lithium-ion batteries (LiBs). Since LiB cells are sensitive to temperature variations, even little variations can result in a reduction in performance or even cell failure. This work introduces a novel cooling system utilizing SiO2-Water Nanofluid and CFD analysis to enhance the thermal management of lithium-ion battery packs with varying silicon dioxide nanoparticle diameters. The results showed that SiO₂ nanofluids with smaller nanoparticle diameters had higher average Nusselt numbers at all Reynolds numbers. This is because smaller nanoparticles have a larger surface area, which increases the collision rate of the nanoparticles with the fluid and thus enhances heat transfer. The increase in Nusselt number was found to be 2.8 %, 5.5 %, 11.6 %, and 22.6 % for nanoparticle sizes of 50, 40, 30, and 20 nm, respectively. The results also showed that for all particle sizes, the temperature of cell 4 equalled the inlet temperature at Re = 30,000. This is because cell 4 is located at the first column of the system and is oriented towards the entrance section, which results in a large temperature difference between the cell and the coolant. Cell 4, therefore, experiences a higher heat discharge to the coolant than the other cells. Overall, this study has shown that smaller nanoparticles and higher Reynolds numbers significantly improve the heat exchange capacity of LiB cells. This can lead to improved electrical properties and extended battery cell lifespan.