Abstract: A redox cell rebalance system is provided. In some embodiments, the rebalance system includes electrochemical cell and a photochemical cell. In some embodiments, the photochemical cell contains a source of ultraviolet radiation for producing HCl from H2 and Cl2 generated by the system. The HCl product may be collected or circulated back through the system for the rebalancing of electrolytes. A rebalance cell for use in a rebalance system is also provided. In some embodiments, the rebalance cell is the combination of an electrochemical cell and a photochemical cell. In some embodiments, a source of ultraviolet radiation is housed in the cathode compartment of the rebalance cell. In some embodiments, the source of ultraviolet radiation is used to effect the formation of HCl from H2 and Cl2 present in the rebalance cell. The HCl is dissolved in aqueous electrolytes contained in the rebalance cell, which can subsequently be circulated through a rebalance system for the rebalancing of redox cells.

Abstract: A method for preparing a redox flow battery electrolyte is provided. In some embodiments, the method includes the processing of raw materials containing sources of chromium ions and/or iron ions. The method further comprises the removal of impurities such as metal ions from those raw materials. In some embodiments, a reductant may be used to remove metal impurities from an aqueous electrolyte containing chromium ions and/or nickel ions. In some embodiments, the reductant is an amalgam. In some embodiments, the reductant is a zinc amalgam. Also provided is a method for removing ionic impurities from an aqueous acid solution. Further provided a redox flow battery comprising at least one electrolyte prepared from the above-identified methods.

Abstract: In accordance with some embodiments, a buck-boost circuit is contemplated which is bi-directional. That is, the buck-boost circuit be configured to produce a load voltage for a load responsive to a source voltage from a voltage source, and the buck-boost circuit may also be configured to produce a charging voltage for the voltage source responsive to a second voltage source connected to the load. In an embodiment, the buck-boost circuit may be operating in boost mode when providing the load voltage and may be operating in buck mode when providing the charging voltage.

Abstract: A controller for controlling a flow cell battery system is provided. The controller operates the flow cell battery system in a plurality of states including a plating state, a charging state and a discharge state.

Abstract: In accordance with some embodiments, a buck-boost circuit is contemplated which is bi-directional. That is, the buck-boost circuit be configured to produce a load voltage for a load responsive to a source voltage from a voltage source, and the buck-boost circuit may also be configured to produce a charging voltage for the voltage source responsive to a second voltage source connected to the load. In an embodiment, the buck-boost circuit may be operating in boost mode when providing the load voltage and may be operating in buck mode when providing the charging voltage.

Abstract: A quencher for a flow cell battery is described. The quencher utilizes a quench solution formed from FeCl2 in a dilute HCl solution in order to quench chlorine emissions from the flow cell battery. A quench sensor is further described. The quench sensor monitors the concentration level of FeCl2 in the quench solution and may also monitor the level of the quench solution in the quencher.

Abstract: A battery charging system according to some embodiments includes a plurality of power modules coupled to a backplane, each of the plurality of power modules providing an electrical indication of type of power module to the backplane, the power modules of each type providing an electrical function associated with charging a battery consistent with the type of power module; and a controller that determines the number of power modules of a particular type and supplies control signals that allocate to each of the power modules of the particular type a portion of the electrical function.

Abstract: A controller for controlling a flow cell battery system is provided. The controller operates the flow cell battery system in a plurality of states including a plating state, a charging state and a discharge state.

Abstract: A method of producing HCl from H2 and Cl2 is provided. In some embodiments, the method comprises at least one photochemical chamber placed in fluid communication with at least one source of H2 and at least one source of Cl2. In some embodiments, the photochemical chamber effects the formation of HCl through the use of at least one source of ultraviolet radiation contained therein. In some embodiments, the HCl product may be captured and used as a gas. In some embodiments, the HCl product may be absorbed into water to form an aqueous HCl solution.

Abstract: A quencher for a flow cell battery is described. The quencher utilizes a quench solution formed from FeCl2 in a dilute HCl solution in order to quench chlorine emissions from the flow cell battery. A quench sensor is further described. The quench sensor monitors the concentration level of FeCl2 in the quench solution and may also monitor the level of the quench solution in the quencher.

Abstract: A leak detection sensor for detecting a leakage of an electrolyte solution in a flow battery system is provided. The sensor includes a sensor housing, the sensor housing being at least partially surrounded by a fluid and having mounted therein at least one light source.

Abstract: A leak detection sensor for detecting a leakage of an electrolyte solution in a flow battery system is provided. The sensor includes a sensor housing, the sensor housing being at least partially surrounded by a fluid and having mounted therein at least one light source.

Abstract: A Vanadium chemistry flow cell battery system is described. Methods of forming the electrolyte, a formulation for the electrolyte, and a flow system utilizing the electrolyte are disclosed. Production of electrolytes can include a combination of chemical reduction and electrochemical reduction.

Abstract: A method for preparing a redox flow battery electrolyte is provided. In some embodiments, the method includes the processing of raw materials that include sources of chromium ions and/or iron ions. The method further comprises the removal of impurities such as metal ions from those raw materials. In some embodiments, an ammonium salt may be used to remove metal impurities from an aqueous mixture of chromium ions and/or iron ions. Further provided is a redox flow battery comprising at least one electrolyte prepared from the above-identified methods.

Abstract: A leak detection sensor for detecting a leakage of an electrolyte solution in a flow battery system is provided. The sensor includes a sensor housing, the sensor housing being at least partially surrounded by a fluid and having mounted therein at least one light source.

Abstract: An electrolyte for a flow cell battery is provided. The electrolyte includes a concentration of chromium ions that is greater than the concentration of iron ions.

Abstract: A method and apparatus for determining the state of charge (SOC) of a battery is discussed. The method involves measuring the terminal voltage across the battery and the current flowing through the battery at a plurality of different times and fitting a line equation with a slope and an intercept to the terminal voltage and current data. The open-circuit voltage (OCV) is calculated from the intercept of the linear equation and the SOC is determined from the OCV by reference to a lookup table.

Abstract: A stacked cell for a flow cell battery is presented. The stacked cell is sealed by a gasket between individual components. The gasket is formed such that it seals against leakage of electrolytes and facilitates the flow of electrolytes through the stacked cell. Further, the gasket is formed to minimize the linear expansion of the gasket material with temperature.

Abstract: An electrode for use in a flow cell is presented. The electrode includes a metal plate for collecting current in the electrode that is bonded between a first and second plate.

Abstract: A sensor for measuring a level of a conductive liquid, is provided. The sensor includes at least two electrodes that can be positioned in a holding tank so as to be partially submerged in the conductive liquid, sensor leads coupled to the at least two electrodes, and circuitry and a controller for determining the properties of the electrolyte, the circuitry being coupled to the at least two electrodes via the sensor leads, and the controller being coupled to the circuitry. The sensor may be used as an electrolyte level sensor in a flow battery system.