Lithium Iron Phosphate (LiFePO4) Battery Power System for Deepwater Emergency Operation

In this paper, a large format 2 KWh lithium iron phosphate (LiFePO4) battery stack power system is proposed for the emergency power system of the UUV. The LiFePO4 stacks are chosen due to their high energy density, modularity and ready availability. The proposed LiFePO4 battery system includes the design and development of a smart battery management system (BMS) with high efficiency active cell balancing technology and intelligent self-learning battery state of charge (SOC) estimation for the LiFePO4 battery. The proposed BMS will lead to better utilization of battery's potential capacity and maximize the cycle life of the battery. The battery system has a pressure-resistance enclosure to eliminate extra battery pressure chamber and associated risks, therefore increase the reliability of the power system amidst high pressures down to 3km of deep-water.