In order to improve the heat dissipation performance of square lithium-ion batteries，a new liquid cooling channel structure is designed. Based on Fluent simulation software，a coupled model of battery heat generation and fluid heat transfer is constructed. The influence of coolant flow rate，inlet temperature，and channel thickness on the cooling effect in the new liquid cooling channel structure is simulated and analyzed. The results show that the new flow channel reduce the maximum temperature of the battery pack by 8.26℃. As the flow rate increases，the maximum temperature of the battery decreases，the temperature difference of the battery does not change much，and the pressure difference of the liquid cooling channel increases significantly. The inlet temperature decreases，the maximum temperature of the battery pack decreases，and the temperature difference is within a reasonable range of variation. As the thickness of the flow channel increases，the maximum temperature of the battery pack rises，the pressure difference decreases，and the temperature difference remains within a reasonable range of variation. To achieve the synergistic goal of higher efficiency and lower energy consumption，a balance needs to be sought between heat dissipation performance and pump functional consumption. A flow rate of 0.4 m/s and a channel thickness of 3 mm are the preferred options.