Abstract

Vanadium redox flow batteries (VRBs) have gained widespread adoption for large-scale energy storage applications, owing to their modular design and long operational lifespan. However, pump faults can severely disrupt electrolyte circulation, resulting in insufficient electrolyte supply, uneven ion concentration distribution, and abnormal electrochemical polarization, which compromise system performance and safety. The operation of VRBs involves the coupling of multiple physical processes, which makes fault analysis particularly challenging. To address this problem, a multiphysics-coupled model is developed using the COMSOL Multiphysics platform based on the conservation laws of momentum, charge, and mass. The model describes the coupled mechanisms among the flow field, concentration field, and electrochemical field. The model is validated through experiments conducted on a small-scale VRB system. Simulation results demonstrate that different pump fault types lead to distinct variations in vanadium ion concentration distribution, potential and overpotential distribution inside the stack, and current density inside the stack. These findings offer predictive insight into the performance degradation associated with pump faults and provide a foundation for the development of accurate fault diagnosis strategies.

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