Optimization design and numerical study on water cooling structure for power lithium battery pack

•An aluminum mini-channel cold plate is optimized and numerical studied to cool down the power lithium battery pack.•The novel design helps to decrease the Tmax and Tdiff of battery pack.•Flow rate and inlet coolant temperature of channels have critical influence on the performance of thermal management.•The cooling structure and parameter can meet requirements at different discharge rates. Lithium-ion batteries are widely used in electric vehicles for their superior performance. The performance of lithium-ion battery can be affected by the issue of overheat. A water cooling strategy combined with mini-channel for the heat dissipation of the lithium battery pack is developedand further optimized in the paper. Three different water cooling strategies are developed. In addition, the cooling performance tests of the designed cooling structures are carried out. Meanwhile, the experiments are also conducted to verify the reliability of the numerical simulation model. The best cooling performance is achieved by structure with cold plates both at the bottom and on two sides of the battery module. On the basis of aforementioned work, influence factors of optimized cooling structure with respect to flow rates, coolant inlet temperatures and discharge rates are also analyzed. The maximum temperature of the battery module decreases with the increase of the flow rate. The 2 L/min inlet flow rate is verified to improve the temperature uniformity of the battery pack significantly. Meanwhile, the maximum temperature of the battery pack can be reduced to 23 ℃, and it temperature difference can be less than 3 ℃. The maximum temperature of the battery pack decreases with the decrease of the inlet coolant temperature, while the temperature difference of the battery changes oppositely. The research results are helpful to improve the thermal performance and safety of lithium-ion batteries.