Redox-flow-batteri

摘要

Conventional redox flow batteries have a shortcoming in that the electrolytes in the positive and negative cells migrate through the membrane over the course of charge and discharge, leading to an increase and decrease in the electrolytes, which substantially reduces electric power over cycles of charge and discharge. The present invention provides a redox flow type battery which is a liquid-circulating battery comprising a battery cell and storage tanks for positive and negative electrolytes, wherein the battery cell is separated by a membrane to provide a positive cell and a negative cell, each cell having a liquid-permeable porous electrode disposed therein, wherein the positive and negative electrolytes are sulfuric acid aqueous solutions with vanadium ion concentrations of 0.5 mol/l to 8 mol/l and the electrolyte which migrates through the membrane over cycles of charge and discharge is returned from the storage tank where the liquid increases to the storage tank where the liquid decreases through a pipe in order to keep the change in the amounts of the positive and negative electrolytes in a certain range while charge and discharge are carried out. It is preferable to set a difference in the liquid levels in two storage tanks to reflux the increased electrolyte by overflow. The battery is capable of continuous charge and discharge for a longer period of time without substantially decreasing the battery characteristics.