Effect of Porous Electrode Configuration on Redox Flow Battery Performance

Redox flow battery is one of promising technologies to enable intermittent and fluctuated wind or solar renewables to provide efficient and reliable electric power in coupled with existing grid. Redox flow battery system consists of storage tanks, pumps, and stack. The stack generates electric power on demand or store electric energy into electrolytes with different redox couples. Electrochemical reaction takes place on the surface of porous felt electrodes in the stack. The felt electrode has three-dimensional structures with anisotropic fiber configuration. High flow rate (> 1mL/mincm) enhances cell performance as a result of improved mass transport, while the high flow rate also entails high pressure drop through the felt (~14 psi), leading to large pumping power loss. The optimal flow rate is determined considering cell performance gain and pumping loss. Flow characteristics and cell performance gain are affected by the fiber configuration and its compression ratio, but are not explored. In this research, we have investigated effects of graphite felt porous electrode direction, compression ratio on performance of vanadium redox flow battery. As a part of our efforts, transverse felt configuration along the flow direction improved low flow rate performance as shown in Figure 1. Felt configuration and cell performance test results will be discussed in this presentation. 25 50 75 100 60 65 70 75 80 85 90 95 100