Abstract: An electrolyte manufacturing device includes an electrolytic cell including a diaphragm separating an anode chamber from a cathode chamber, a circulator circulating an anolyte to the anode chamber and circulating a catholyte to the cathode chamber, and a power source supplying current. A cathode in the electrolytic cell includes a carbon fiber layer on a plane facing the diaphragm. The electrolytic cell includes an anode net placed between the anode and the diaphragm, and a cathode net placed between the cathode and the diaphragm. The circulator circulates the anolyte at a flow rate that is greater than the flow rate of the catholyte and is equal to or greater than twice the volume of gaseous oxygen generated in the anode chamber per unit time at 0° C.

Abstract: An object of the disclosure is to provide a method of efficiently producing a highly-pure vanadium electrolytic solution from a combustion residue that is discharged from facilities such as refineries and power plants and contains uncombusted carbon. The method of producing a vanadium electrolytic solution for redox flow cell (RFB) includes a vanadium eluate generation step of obtaining a vanadium eluate in which vanadium is dissolved. The vanadium is contained in a combustion residue obtained after combustion of a fossil fuel. The method further includes a precipitation step of mixing a sulfide precipitant into the vanadium eluate to precipitate a solid substance of precipitate in a reduction state and a wet oxidation step including a process of adding dilute sulfuric acid to the solid substance separated from the solution to generate a vanadium sulfate solution.

Abstract: A redox flow battery includes: a positive electrolyte storage tank; a negative electrolyte storage tank; a cell stack; a positive electrolyte outward path that sends positive electrolyte to positive electrode chambers in the cell stack; a positive electrolyte return path that sends positive electrolyte to the positive electrolyte storage tank; a negative electrolyte outward path that sends negative electrolyte to negative electrode chambers of the cells; a negative electrolyte return path that sends negative electrolyte to the negative electrolyte storage tank; an entrance open circuit voltage measuring portion that measures an upstream open circuit voltage between the positive electrolyte inside the positive electrolyte outward path and the negative electrolyte inside the negative electrolyte outward path; and an exit open circuit voltage measuring portion that measures a downstream open circuit voltage between the positive electrolyte inside the positive electrolyte return path and the negative electrolyte

Abstract: A redox flow battery includes: a positive electrolyte storage tank; a negative electrolyte storage tank; a cell stack; a positive electrolyte outward path that sends positive electrolyte to positive electrode chambers in the cell stack; a positive electrolyte return path that sends positive electrolyte to the positive electrolyte storage tank; a negative electrolyte outward path that sends negative electrolyte to negative electrode chambers of the cells; a negative electrolyte return path that sends negative electrolyte to the negative electrolyte storage tank; an entrance open circuit voltage measuring portion that measures an upstream open circuit voltage between the positive electrolyte inside the positive electrolyte outward path and the negative electrolyte inside the negative electrolyte outward path; and an exit open circuit voltage measuring portion that measures a downstream open circuit voltage between the positive electrolyte inside the positive electrolyte return path and the negative electrolyte