Computational design of flow fields for vanadium redox flow batteries via topology optimization

Vanadium redox flow battery (VRFB) is a rechargeable battery, which has attracted attention as a next-generation electrochemical energy storage system. It is widely known that achieving high performance in terms of power density is critical for the commercialization of VRFBs. The aim of this paper is to propose a computational design approach for automatically generating an optimized flow field design of a VRFB to achieve high performance without relying on the designer's intuition. To realize this, we focus on generating a freeform configuration of the flow field in a VRFB via topology optimization, which is known as a powerful design tool that is based on numerical optimization. In this study, to improve the mass transfer effect in a VRFB, we formulate the topology optimization problem as a maximization problem of the electrode surface concentration in the negative electrode during the charging process. We demonstrate through numerical investigation that a topology-optimized flow field can be obtained. As a result, it is revealed that the interdigitated flow field is an optimal flow field of the VRFB under the investigated operating conditions.