Abstract: One embodiment is a redox flow battery system that includes an anolyte; a catholyte; an anolyte tank configured for holding at least a portion of the anolyte; a catholyte tank configured for holding at least a portion of the catholyte; a primary redox flow battery arrangement, and a second redox flow battery arrangement. The primary and secondary redox flow battery arrangements share the anolyte and catholyte tanks and each includes a first half-cell including a first electrode in contact with the anolyte, a second half-cell including a second electrode in contact with the catholyte, a separator separating the first half-cell from the second half-cell, an anolyte pump, and a catholyte pump. The peak power delivery capacity of the secondary redox flow battery arrangement is less than the peak power delivery capacity of the primary redox flow battery arrangement.

Abstract: One embodiment is a redox flow battery system that includes an anolyte; a catholyte; an anolyte tank configured for holding at least a portion of the anolyte; a catholyte tank configured for holding at least a portion of the catholyte; a primary redox flow battery arrangement, and a second redox flow battery arrangement. The primary and secondary redox flow battery arrangements share the anolyte and catholyte tanks and each includes a first half-cell including a first electrode in contact with the anolyte, a second half-cell including a second electrode in contact with the catholyte, a separator separating the first half-cell from the second half-cell, an anolyte pump, and a catholyte pump. The peak power delivery capacity of the secondary redox flow battery arrangement is less than the peak power delivery capacity of the primary redox flow battery arrangement.

Abstract: A redox flow battery system includes an anolyte; a catholyte; a first electrode structure including a first electrode, a second electrode, and a base disposed between the first and second electrodes, the base including a thermoplastic material and conductive elements disposed in the thermoplastic material, wherein at least one of the first electrode or the second electrode is thermally bonded to the base by heating the base to soften the thermoplastic material and pressing the at least one of the first electrode or the second electrode into the thermoplastic material of the base; a first half-cell in which the first electrode is in contact with the anolyte; and a second half-cell in which the second electrode is in contact with the catholyte.

Abstract: A redox flow battery system includes an anolyte; a catholyte; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; a separator separating the anolyte in the first half-cell from the catholyte in the second half-cell; at least one state measurement device configured for intermittently, periodically, or continuously making a measurement of a value indicative of a state of charge of the anolyte or the catholyte before entering or after leaving the first half-cell or second half-cell, respectively; and a controller coupled to the at least one state measurement device for generating a temporal energy profile of the anolyte or the catholyte, respectively, using the measurements.

Abstract: A redox flow battery system includes an anolyte having chromium ions in solution, wherein at least a portion of the chromium ions form a chromium complex with at least one of the following: NH3, NH4+, CO(NH2)2, SCN?, or CS(NH2)2; a catholyte having iron ions in solution; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; and a first separator separating the first half-cell from the second half-cell.

Abstract: One embodiment is a redox flow battery system that includes an anolyte; a catholyte; an anolyte tank configured for holding at least a portion of the anolyte; a catholyte tank configured for holding at least a portion of the catholyte; a primary redox flow battery arrangement, and a second redox flow battery arrangement. The primary and secondary redox flow battery arrangements share the anolyte and catholyte tanks and each includes a first half-cell including a first electrode in contact with the anolyte, a second half-cell including a second electrode in contact with the catholyte, a separator separating the first half-cell from the second half-cell, an anolyte pump, and a catholyte pump. The peak power delivery capacity of the secondary redox flow battery arrangement is less than the peak power delivery capacity of the primary redox flow battery arrangement.

Abstract: One embodiment is a redox flow battery system that includes an anolyte; a catholyte; an anolyte tank configured for holding at least a portion of the anolyte; a catholyte tank configured for holding at least a portion of the catholyte; a primary redox flow battery arrangement, and a second redox flow battery arrangement. The primary and secondary redox flow battery arrangements share the anolyte and catholyte tanks and each includes a first half-cell including a first electrode in contact with the anolyte, a second half-cell including a second electrode in contact with the catholyte, a separator separating the first half-cell from the second half-cell, an anolyte pump, and a catholyte pump. The peak power delivery capacity of the secondary redox flow battery arrangement is less than the peak power delivery capacity of the primary redox flow battery arrangement.

Abstract: A redox flow battery system includes an anolyte having chromium ions in solution, wherein at least a portion of the chromium ions form a chromium complex with at least one of the following: NH3, NH4+, CO(NH2)2, SCN?, or CS(NH2)2; a catholyte having iron ions in solution; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; and a first separator separating the first half-cell from the second half-cell.

Abstract: A redox flow battery system includes an anolyte; a catholyte; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; a separator separating the anolyte in the first half-cell from the catholyte in the second half-cell; at least one state measurement device configured for intermittently, periodically, or continuously making a measurement of a value indicative of a state of charge of the anolyte or the catholyte before entering or after leaving the first half-cell or second half-cell, respectively; and a controller coupled to the at least one state measurement device for generating a temporal energy profile of the anolyte or the catholyte, respectively, using the measurements.

Abstract: A method for preparation of electrolyte for a redox flow battery includes reducing chromium ore using a carbon source to convert the chromium ore to an iron/chromium alloy with carbon particles; dissolving the iron/chromium alloy with carbon particles in sulfuric acid to form a first solution; adding calcium chloride or barium chloride to the first solution to produce a second solution including FeCl3 and CrCl3; and adding an acid to the second solution to form the electrolyte. Other methods can be used for preparing an electrolyte from chromium waste material.

Abstract: A redox flow battery system includes an anolyte; a catholyte; a first electrode structure including a base having a first surface and a second surface opposite the first surface, a first electrode disposed on the first surface, a second electrode disposed on the second surface, and conductive elements that extend through the base, wherein the base resists flow of anolyte and catholyte through the base and each of the conductive elements includes a first end portion exposed at the first surface and a second end portion exposed at the second surface, wherein the first electrode includes the first end portions of the conductive elements and the second electrode includes the second end portions of the conductive elements; a first half-cell in which the first electrode is in contact with the anolyte; and a second half-cell in which the second electrode is in contact with the catholyte.

Abstract: In one embodiment, a redox flow battery includes an electrochemical cell in fluid communication with anolyte and catholyte working electrolytes, and a primary OCV cell to measure the potential difference between the positive and negative working electrolyte, and a reference OCV cell to measure the potential difference between the reference cell working electrolyte, which is one of the anolyte and catholyte working electrolytes, and a reference electrolyte, wherein the reference electrolyte has a known potential. In another embodiment, a method of operating a redox flow battery includes calculating the potential values of the anolyte and catholyte working electrolytes based on the known potential values of the reference electrolyte and the first and second potential difference values obtained from the primary OCV cell and the reference OCV cell.

Abstract: In one embodiment, a cell in a redox flow battery includes a first flow frame for flow of a catholyte, a second flow frame for flow of an anolyte, and a separator between the first flow frame and the second flow frame, wherein the separator has a first side and a second side and an outer perimeter, and a gasket-and-separator assembly including a gasket assembly laminated to the separator, wherein the gasket assembly seals the outer perimeter of the separator on the first side and the second side.

Abstract: In one embodiment of the present disclosure, an electrochemical cell includes a positive portion including a cathode and a catholyte half-cell and a negative portion including an anode and an anolyte half-cell, wherein at least one of the catholyte half-cell and the anolyte half-cell has a plurality of electrolyte flow areas; an ion transfer membrane separating the positive portion and the negative portion; and at least one positive current collector in contact with the cathode and at least one negative current collector in contact with the anode.

Abstract: Composite separators having a porous structure and including acid-stable, hydrophilic, inorganic particles enmeshed in a substantially fully fluorinated polyolefin matrix can be utilized in a number of applications. The inorganic particles can provide hydrophilic characteristics. The pores of the separator result in good selectivity and electrical conductivity. The fluorinated polymeric backbone can result in high chemical stability. Accordingly, one application of the composite separators is in redox flow batteries as low cost membranes. In such applications, the composite separator can also enable additional property-enhancing features compared to ion-exchange membranes. For example, simple capacity control can be achieved through hydraulic pressure by balancing the volumes of electrolyte on each side of the separator.

Abstract: A method of operating an all vanadium redox flow battery includes providing an all vanadium redox flow battery comprising an anolyte storage tank including a volume of anolyte and a catholyte storage tank including a volume of catholyte; an electrochemical cell in fluid communication with the anolyte and catholyte storage tanks; and a predetermined range for the ratio of vanadium concentration between the anolyte and the catholyte; and transferring an amount of catholyte from the catholyte storage tank to the anolyte storage tank, or an amount of anolyte from the anolyte storage tank to the catholyte storage tank, to restore the ratio of vanadium concentration to the predetermined range. An all vanadium redox flow battery system includes means for transferring anolyte and catholyte between the anolyte and catholyte storage tanks to maintain a predetermined range for the ratio of vanadium concentration between the anolyte and the catholyte.