Optimizing vanadium redox flow battery system power loss using particle swarm optimization technique under different operating conditions

Battery storage performance optimization is crucial in ensuring the reliable operation of renewable energy integrated power systems and emergency backup applications. Considering the long life cycle and several other merits such as deep discharge capacity, scalability of power, and energy capacity, Vanadium Redox Flow Battery (VRFB) has become one of the most potential storage solutions for stationary storage applications compared to the other conventional batteries. In this paper, a kW scale VRFB storage system power loss optimization based on the particle swarm optimization (PSO) technique has been demonstrated for the first time. It is a multi-variable optimization considering both the VRFB pump power loss and stack power loss simultaneously. The electrolyte flow rate has been considered as the control variable in optimizing the overall VRFB system power loss. Charge-discharge operations of VRFB with four sets of electrolyte flow rates at three different levels of stack terminal current have been taken for validation of the proposed work. It has been observed that for a 1 kW 6kWh VRFB storage system, the overall system power loss becomes the minimum at an optimal flow rate of 6 L/min for a range of (3-18) L/min of electrolyte flow rate at 40, 45, and 50 A charge-discharge operations. The proposed work formulation demonstrated in this paper is a generalized one and can be very useful for maximizing the overall system efficiency of VRFB storage and ensuring the reliability of VRFB integrated power system applications.