Lockheed Martin Energy, LLC

Kean L Duffey

Adam Morris-Cohen

John Goeltz

Evan R King

Jeremy S Loretz

Steven Y Reece

Jonathan Hamel

Michael Bufano

Sophia Lee

Peter F Hays

Jeremy Loretz

The present invention relates to methods and apparatuses for determining the ratio of oxidized and reduced forms of a redox couple in solution, each method comprising: contacting first and second stationary working electrodes and first and second counter electrode to the solution; applying a first potential at the first stationary working electrode and a second potential at the second stationary working electrode relative to the respective counter electrodes and measuring first and second constant currents for the first and second stationary working electrodes, respectively; wherein the first and second constant currents have opposite signs and the ratio of the absolute values of the first and second constant currents reflects the ratio of the oxidized and reduced forms of the redox couple in solution. When used in the context of monitoring/controlling electrochemical cells, additional embodiments include those further comprising oxidizing or reducing the solution.

Apparatus and method for determining state of charge in a redox flow battery via limiting currents

Provided are flow batteries that include a fluidic train within a dynamic fluidic network system which fluidic train is convertible between a first state and a second state, the first state the first state placing a main electrolyte source and a dynamic fluidic network, outside the fluidic train and an electrode region, into fluid communication with the electrode region and the second state placing the main electrolyte source and the dynamic fluidic network, outside the fluidic train and the electrode region, into fluid isolation from the electrode region and placing the electrode region into fluid communication with a sampling segment. Also provided are methods of operating flow batteries.

Flow battery with a dynamic fluidic network

The present invention relates to methods and apparatuses for determining the ratio of oxidized and reduced forms of a redox couple in solution, each method comprising: (a) contacting a first stationary working electrode and a first counter electrode to the solution; (b) applying a first potential at the first working electrode and measuring a first constant current; (c) applying a second potential at the first working electrode and measuring a second constant current; wherein the sign of the first and second currents are not the same; and wherein the ratio of the absolute values of the first and second currents reflects the ratio of the oxidized and reduced forms of the redox couple in solution. When used in the context of monitoring/controlling electrochemical cells, additional embodiments include those further comprising (d) oxidizing or reducing the solution, so as to alter the balance of the oxidized and reduced forms of the redox couple in solution, to a degree dependent on the ratio of the absolute values of the first and second currents. These embodiments may be used in the context of maintaining an electrochemical cell, stack, or system.

During operation of flow battery systems, the volume of one or more electrolyte solutions can change due to solvent loss processes. An electrochemical balancing cell can be used to combat volume variability. Methods for altering the volume of one or more electrolyte solutions can include: providing a first electrochemical balancing cell containing a membrane disposed between two half-cells, establishing fluid communication between a first aqueous electrolyte solution of a flow battery system and a first half-cell of the first electrochemical balancing cell, and applying a current to the first electrochemical balancing cell to change a concentration of one or more components in the first aqueous electrolyte solution. Applying the current causes water to migrate across the membrane, either to or from the first aqueous electrolyte solution, and a rate of water migration is a function of current.

Concentration management in flow battery systems using an electrochemical balancing cell

The invention concerns methods of determining the state of charge of a half-cell within a redox flow battery, the method comprising: (i) measuring the rate of change in equilibrium half-cell reduction potential of the electrolyte as charge is passed into the electrolyte solution within the cell; and (ii) correlating said rate of change in equilibrium half-cell reduction potential with the state of charge of said half-cell. Other aspects of the invention concern balancing the state of charge of a flow battery and methods of calibrating an oxidation/reduction probe.

Methods for determining state of charge and calibrating reference electrodes in a redox flow battery

The present invention relates to redox flow batteries and methods and apparatuses for monitoring the compositions of the electrolytes therein. In particular, the present invention relates to methods and configurations for monitoring the state-of-charge of an electrolyte stream of a flow cell or flow battery.

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Arlington, VA, United States of America

Kean L Duffey