Efficient management of large-capacity lithium iron phosphate batteries within a reasonable temperature range and maintenance of temperature consistency among batteries are a crucial prerequisite for the safe and stable operation of electrochemical energy storage systems. To enhance the thermal management capability of large-capacity battery energy storage systems

a composite thermal management system based on liquid cooling combined with phase change materials is proposed. Firstly

taking a 280 Ah lithium iron phosphate battery as the research object

we established a three-dimensional battery electro-thermal coupling model by considering battery size

heat generation from busbar

etc. The model is then extended to a module system with 52 battery cells connected in series to obtain its temperature distribution characteristics. Subsequently

a liquid cooling plate is added at the bottom of the module

and by changing the flow rate of the cooling liquid

the average temperature

maximum temperature difference

and pressure difference at the inlet and outlet of the flow channel of different batteries within the module are compared. The appropriate flow rate is selected based on a comprehensive consideration of energy consumption and effect. Finally

on the basis of liquid cooling

phase change materials are added to fill the gaps between batteries within the module to achieve a composite thermal management method by combining liquid cooling and phase change materials. The results show that

during discharge

the maximum temperature difference is within 1.5 ℃ and the highest average temperature is 51.93 ℃ when using the composite thermal management method. Compared with the single liquid cooling thermal management

the maximum temperature difference and the highest average temperature are further reduced by 1.1 ℃ and 3.01 ℃

respectively

proving the effectiveness of the composite thermal management system.