A redox flow battery includes a battery cell to which a positive electrolyte and a negative electrolyte are supplied, and an electrical quantity measurement system configured to measure a quantity of electricity when a predetermined amount of electrolyte is discharged, for at least one of the positive electrolyte and the negative electrolyte. The electrical quantity measurement system includes an electrolytic cell having a working electrode to which one of the positive electrolyte and the negative electrolyte, in which the quantity of electricity is to be measured, is supplied, and a counter electrode to which the other electrolyte, which is not to be measured, is supplied; a standard electrode disposed, outside the electrolytic cell, so as to be in contact with the one electrolyte to be measured; and a measurement device configured to apply, to the electrolytic cell, a voltage that is set on the basis of a potential of the standard electrode and capable of performing total electrolysis of the one electrolyte contained in the working electrode and measure the quantity of electricity of the one electrolyte.
展开▼