J061051 レドックスフロー電池性能向上のための電極構造と電解液流動に関する研究(〔J061-05〕燃料電池・二次電池におけるナノ・マイクロ現象とマクロ性能(5):各種電池)

Abstract

The use of the redox flow battery as a large-capacity rechargeable battery is one of the solutions for equalization of the outputs of wind power and photovoltaic power. In this study, we focus on electrode structure and the electrolyte flow of the redox flow battery, because those optimum design is necessary for improving total system performance. We tested with three kinds of electrode structure, and confirmed the influence of the electrolyte flow rate. At low SOC (state of charge), the discharge performance is greatly affected by the concentration overpotential at low flow rate of the electrolyte. In the case of the electrode structure with electrolyte flow channel, the effect of the concentration overpotential becomes larger in comparison with the electrode structure without electrolyte flow channel, indicating that most electrolyte flows in the flow channel and diffusion of the reactant is dominant for the cell performance. With the electrode without the channel (3mm or 6mm thick carbon felt), the effect of electrode thickness is small up to current density around 40mA/cm^2 even at low electrolyte flow rate, while thicker electrode improves the cell performance at high current density because of the larger effective reaction area of the carbon felt.