Simulation study on the cooling performance of immersion cooling systems for energy storage battery pack

Compared with air cooling and cold plate cooling, immersion cooling has better cooling effect, lower energy consumption and maintenance cost, and is gradually applied to energy storage systems. In this paper, the effects of battery spacing, inlet and outlet mode, coolant flow rate, coolant type and parameter on cooling effect in a large-scale battery pack are studied by numerical simulation. The results show that the cooling effect increases first and then decreases with the increase of battery spacing, the maximum temperature reaches a minimum value of 35.62°C at a spacing of 2.5 mm. The influence of inlet position on cooling effect is greater than that of outlet position, the minimum average temperature at the high inlet is 31.09°C, a decrease of 4.01% compared to the low inlet. The cooling effect increases with the increase of coolant flow rate, but the magnitude of enhancement decreases gradually, the average temperature decreased by 21.66% in low flow rate, but decreased by only 1.13% in high flow rate. Water-based has the lowest average temperature at 28.19°C, while silicone oil has the highest average temperature, representing a relative increase of 21.78%, and the average temperature of fluoride, hydrocarbon and ester is similar, at 32.92°C, 33.5°C, and 33.25°C respectively. The effect of density and specific heat capacity on cooling effect is very significant, while the effect of thermal conductivity and kinematic viscosity is very small. The research results of this paper can provide valuable insights and references for the design and optimization of the immersion cooling system.