A method of operating an iron redox flow battery system may comprise fluidly coupling a plating electrode of an iron redox flow battery cell to a plating electrolyte; fluidly coupling a redox electrode of the iron redox flow battery cell to a redox electrolyte; fluidly coupling a ductile plating additive to one or both of the plating electrolyte and the redox electrolyte; and increasing an amount of the ductile plating additive to the plating electrolyte in response to an increase in the plating stress at the plating electrode. In this way, ductile Fe can be plated on the negative electrode, and the performance, reliability and efficiency of the iron redox flow battery can be maintained. In addition, iron can be more rapidly produced and plated at the plating electrode, thereby achieving a higher charging rate for all iron flow batteries.

An anaerobic aluminum-water electrochemical cell that includes: a plurality of electrode stacks, each electrode stack featuring an aluminum or aluminum alloy anode, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, an electrolyte, and the physical separators; a water injection port, in the housing, configured to introduce water into the housing. The electrochemical cell also includes an amount of hydroxide base sufficient to form an electrolyte having a hydroxide base concentration of at least 0.05 M to at most 3 M when water is introduced between the anode and at least one cathode of the electrochemical cell. The aluminum or aluminum alloy of the anode is substantially free of titanium and boron.

An anaerobic aluminum-water electrochemical cell is provided. The electrochemical cell includes: a plurality of electrode stacks, each electrode stack including an aluminum or aluminum alloy anode, and at least one cathode configured to be electrically coupled to the anode; one or more physical separators between each electrode stack adjacent to the cathode; a housing configured to hold the electrode stacks, an electrolyte, and the physical separators; a water injection port, in the housing, configured to introduce water into the housing, and an amount of hydroxide base sufficient to form an electrolyte having a hydroxide base concentration of at least 0.5% to at most 13% of the saturation concentration when water is introduced between the anode and the least one cathode. The aluminum or aluminum alloy of the anode is substantially free of titanium and boron.

A redox flow battery includes first and second cells. Each cell has electrodes and a separator layer arranged between the electrodes. A first circulation loop is fluidly connected with the first electrode of the first cell. A polysulfide electrolyte solution has a pH 11.5 or greater and is contained in the first recirculation loop. A second circulation loop is fluidly connected with the second electrode of the second cell. An iron electrolyte solution has a pH 3 or less and is contained in the second circulation loop. A third circulation loop is fluidly connected with the second electrode of the first cell and the first electrode of the second cell. An intermediator electrolyte solution is contained in the third circulation loop. The cells are operable to undergo reversible reactions to store input electrical energy upon charging and discharge the stored electrical energy upon discharging.

The present disclosure relates to an electrochemical cell comprising a fuel electrode for oxidizing a fuel, an oxidant electrode for reducing an oxidant, and an ionically conductive medium for conducting ions between the fuel and oxidant electrodes to support electrochemical reactions at the fuel and oxidant electrodes. The ionically conductive medium comprises at least one active additive for enhancing (controlling the rate, overpotential and/or the reaction sites for) at least one electrochemical reaction within the cell. The cell further comprises an additive medium in contact with the ionically conductive medium and containing the at least one active additive capable of corroding or dissolving in the ionically conductive medium. The additive medium and/or casing is configured to release the active additive to the ionically conductive medium as a concentration of the active additive in the ionically conductive medium is depleted during operation of the cell.

Disclosed herein is a redox flow battery (RFB). The battery generally includes: a positive electrolyte that is a first metal ion, a negative electrolyte that is a second metal ion, an ion exchange membrane positioned between the positive electrolyte and the negative electrolyte. The membrane is configured to restrict and/or prevent the passage of the first metal ion and/or the second metal ion therethrough, and is configured to maintain ionic conductivity between the positive electrolyte and the negative electrolyte.

One embodiment provides a method for predicting maintenance of a redox flow battery, the method including: receiving, from a plurality of sensors, data regarding characteristics of the redox flow battery; weighting, using a processor, each of the characteristics to form an estimated state parameter for the redox flow battery; and determining, using the processor, a maintenance action for the redox flow battery using the estimated state parameter. Other aspects are described and claimed.

According to one embodiment of the present invention, the method for controlling the pump speed of a redox flow battery for transferring an electrolyte stored in an electrolyte tank to a cell stack comprises the steps of: measuring the input power and/or the output power of the redox flow battery; measuring the charging power and/or the discharging power of the redox flow battery; calculating the power loss of the redox flow battery by using the difference between the input power and the charging power, or the difference between the output power and the discharging power; and adjusting the pump speed according to the power loss.

The present disclosure relates to an electrochemical cell comprising a fuel electrode for oxidizing a fuel, an oxidant electrode for reducing an oxidant, and an ionically conductive medium for conducting ions between the fuel and oxidant electrodes to support electrochemical reactions at the fuel and oxidant electrodes. The ionically conductive medium comprises at least one active additive for enhancing (controlling the rate, overpotential and/or the reaction sites for) at least one electrochemical reaction within the cell. The cell further comprises an additive medium in contact with the ionically conductive medium and containing the at least one active additive capable of corroding or dissolving in the ionically conductive medium. The additive medium and/or casing is configured to release the active additive to the ionically conductive medium as a concentration of the active additive in the ionically conductive medium is depleted during operation of the cell.

The present invention relates to an electrolyte storage unit applicable to redox flow batteries and a vanadium redox flow battery including the same. The electrolyte storage unit for redox flow batteries of the present invention can be useful in minimizing a contact area of an electrolyte with the air to improve a self-discharge phenomenon of a battery and solving a problem such as an imbalance between a concentration and a volume of the electrolyte, which is caused during battery driving. Accordingly, a cycle of a process of regenerating an electrolyte can be delayed, and capacity and lifespan characteristics of the battery can be improved. Also, the electrolyte storage unit of the present invention can be easily handled and installed because electrolytes may not be easily mixed even by external impact.