ELECTROLYTE FOR ELECTROLYTE CIRCULATION-TYPE BATTERY, AND ELECTROLYTE CIRCULATION-TYPE BATTERY SYSTEM

摘要

Provided is an electrolyte for a flow battery, the electrolyte being supplied to a flow battery, in which a total concentration of ions of elements of groups 1 to 8 and ions of elements of groups 13 to 16 in the fifth period of the periodic table, and ions of elements of groups 1, 2, and 4 to 8 and ions of elements of groups 13 to 15 in the sixth period of the periodic table, the ions being impurity element ions involved in generation of a gas containing elemental hydrogen, is 610 mg/L or less, a concentration of vanadium ions is 1 mol/L or more and 3 mol/L or less, a concentration of free sulfuric acid is 1 mol/L or more and 4 mol/L or less, a concentration of phosphoric acid is 1.0 × 10^-4 mol/L or more and 7.1 × 10^-1 mol/L or less, a concentration of ammonium is 20 mg/L or less, and a concentration of silicon is 40 mg/L or less. When a charging and discharging test is performed by circulating and supplying the electrolyte to the flow battery under specific conditions, a generation rate of hydrogen is less than 10 cc/h/m² and a generation rate of hydrogen sulfide is less than 5.0 × 10^-3 cc/h/m², the hydrogen and the hydrogen sulfide being generated in a negative electrode of the flow battery during charging and discharging.