Numerical Investigation of Electrolyte Feed System Designs at the Stack Level of Vanadium Redox Flow Batteries

<div class="section abstract"><div class="htmlview paragraph">The rise of electric vehicles (EVs) highlights the need to transition to a renewable energy society, where power is generated from sustainable sources. This shift is driven by environmental, economic, and energy security concerns. However, renewable energy sources like wind and solar are intermittent, necessitating extensive energy storage systems. Vanadium redox flow batteries (VRFBs) are promising for large-scale energy storage due to their long cycle life, scalability, and safety. In VRFBs, cells are typically connected in series to increase voltage, with electrolytes introduced through parallel flow channels using a single manifold. This design, while simple and low in pressure drop, often leads to imbalanced flow rates among cells, affecting performance. Balancing flow rates is crucial to minimize uneven overpotential and enhance durability, presenting an optimization challenge between achieving uniform flow and minimizing pressure drop. This study developed numerical models to evaluate different electrolyte feed system designs in a 64-cell stack using computational fluid dynamics. The outcomes indicated that the feed system employing a tree-like structure design achieved a uniform flow rate while still maintaining acceptable pressure drop levels. Additionally, the influence of the branching order of the tree-like structure was examined. The optimized designs offer a framework for improving flow rate imbalances in practical VRFBs, advancing sustainable energy storage.</div></div>