A computationally efficient, zero-dimensional stack model for simulating redox flow battery performance

Scaling redox flow battery (RFB) innovations from single cells to stacks is an important step for concept validation, but this procedure is challenging, as new processes emerge that impact performance and durability. Models that facilitate performance predictions from material properties and single-cell measurements can inform stack engineering and streamline iterative design-build-test cycles. Here, we deploy a semi-analytical zero-dimensional modeling framework to rapidly simulate stack cycling performance, focusing on failure modes that are particularly relevant for RFB scale-up (i.e., shunt currents, pressure losses, crossover). We first investigate the computational efficiency of the model, yielding simulations times under 0.04 s per cycle—orders of magnitude faster than previous stack models described in the open literature. Next, we explore the role of shunt currents in RFB cycling, discussing the theoretical underpinnings of these parasitic losses and providing generalized predictions of stack performance under variable operating conditions. We then apply the model to evaluate engineering considerations for emerging aqueous-organic RFBs—specifically, we assess manifold design factors influencing tradeoffs between shunt and hydraulic losses as well as membrane selection criteria for long-duration cycling. Ultimately, we anticipate this work will aid in accelerating the cell-to-stack translation by providing an accessible, computationally light model to the RFB community and deepening intuition for performance losses in electrochemical stacks.