The present invention provides a redox flow type battery which 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 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.
