Development of battery thermal management system for LiFeMnPO4 module using air cooling method to minimize cell temperature differences and parasitic energy

In this work, we develop battery thermal management system for high capacity lithium-ion module by using air cooling method to minimize the differences of battery cell's temperature by comparing the parasitic energy consumed by the cooling fan system. The battery thermal management system utilizes two brushless fans, an evaporator unit, an insulation box, a programmable logic control (PLC) and sensors to monitor the operational and the performance of the battery cells. The battery module consists of four high capacity lithium iron manganese phosphate (LiFeMnPO4) battery cells with the nominal voltage of 3.2V and the nominal capacity of 100Ah which are connected in series. To get the initial battery cells thermal characteristic in time series, C5, C10, and C20 discharging methods have been conducted to the battery module using programmable load controller. Based on these thermal characteristics, we demonstrate thermal management system using active control of air cooling system to reduce the temperature rises and temperature differences between battery cells. The results show that the implemented battery thermal management system affects the amount of energy that can be utilized from the battery module. In the C5 discharging process, by using 40 % of fan speed control, the amount of energy that can be drawn from battery module was 3044 kJ including 19.3 kJ as the parasitic energy, and the highest battery cell temperature differences was 3.9 Celsius. This amount of energy was 5.1% higher than that of without the thermal management system.