(361c) A Steady-State Model of a Sub-Scale Flow Battery System

As we move towards the next generation of the electricity grid, energy storage devices will play a significant role in how electricity is produced, transmitted and consumed. For example, the penetration of renewable energy sources such as solar and wind energy into the electric grid is likely to increase in the future. However, the intermittent nature of these renewable sources makes them non-dispatchable and as a result these renewable energy sources have to be operated in conjunction with energy storage systems to realize their full potential. At the other end of the value chain the end-users who are subjected to time-of-use pricing of electricity can benefit from energy arbitrage made possible by energy storage technologies. Flow battery technology is one of the energy storage technologies that can make an impact along the entire value chain of electricity production, transmission and consumption. In this work we will focus on the flow battery technology. The flow battery consists of an ion-exchange membrane sandwiched between two porous electrodes. Liquid electrolytes forming the redox couples are passed through these electrodes. The redox reactions in the electrodes occur in opposite directions during the charging and discharging operation as shown in Figure 1. In this work, we present a 2-dimensional steady-state model of a sub-scale flow battery cell. This model solves for the reaction kinetics in the electrodes, transport (convection, diffusion) in electrodes, and ionic and electronic conduction in the electrode and the membrane. Using this mathematical model we investigate the performance of the flow battery as a function of various cell configurations. The variations in the electrode properties and in flow configurations were investigated. The insights obtained from the simulation of these models will be presented and discussed.