With the increasingly prominent environmental problems and energy crisis, wind power, solar power and other new energy has been rapid development, and energy storage technology is of great significance to the development of new energy. Compared with the power batteries applied in electric vehicles, battery energy storage systems gather a larger number of batteries and a larger scale, usually up to megawatts or 100 megawatts. During the operation of the energy storage system, the lithium-ion battery continues to charge and discharge, and its internal electrochemical reaction will inevitably generate a lot of heat. If the heat is not dispersed in time, the temperature of the lithium-ion battery will continue to rise, which will seriously affect the service life and performance of the battery, and even cause thermal runaway leading to explosion. It is of great significance for promoting the development of new energy technologies to carry out research on the thermal model of lithium-ion batteries, accurately describe and predict the temperature rise of batteries, design energy storage system and thermal management system of battery modules based on heat flow numerical simulation, reduce the maximum operating temperature of lithium-ion batteries, improve the overall temperature uniformity of battery packs, and ensure the safe and reliable operation of lithium-ion power batteries. According to the actual size of a company's energy storage products, this paper also considered the liquid cooling cooling system, air cooling cooling system and lithium-ion battery module heat production system, established a thermal fluid simulation model, studied the cooling effect of different inlet and outlet positions of coolant and different inlet and outlet structures of energy storage cabinet, and selected the optimal layout structure to improve the overall temperature equalization of the energy storage system.