An electrochemical thermal model for vanadium redox flow battery lifetime estimation under dynamic loading conditions

Abstract Vanadium redox flow batteries (VRFBs) offer a scalable and durable solution for integrating intermittent renewable energy sources into the power grid. To evaluate their performance under realistic operating conditions, we present a high-precision two-dimensional multiphysics model for VRFBs that captures the coupling relationships between electrochemical reactions and thermodynamics. A statistically derived long-term varying power profile is compared with a continuous current load of equivalent average current to evaluate battery performance under significant load variations. The results indicate a reduction in system efficiency, with an approximate 8% decrease under dynamic loading conditions, primarily due to current fluctuations and increased pump power demands. However, the state of health (SOH) remained largely unaffected, stabilizing around 99.3%, which suggests minimal degradation over a full day of intermittent operation. This suggests that VRFBs can effectively handle intermittent operation without significant degradation, making them suitable for renewable energy integration.