Lockheed Martin Energy, LLC

Adam Morris-Cohen

Kean L Duffey

John Goeltz

Steven Y Reece

Evan R King

Jeremy S Loretz

Jonathan Hamel

Michael Bufano

Arthur J Esswein

Matthew Millard

Srivatsava Venkataranga Puranam

Peter F Hays

Sophia Lee

Roger Frisbee

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 circulation rates of the electrolyte solutions in a flow battery can impact operating performance. Adjusting the circulation rates can allow improved performance to be realized. Flow battery systems having adjustable circulation rates can include a first half-cell containing a first electrolyte solution, a second half-cell containing a second electrolyte solution, at least one pump configured to circulate the first electrolyte solution and the second electrolyte solution at adjustable circulation rates through at least one half-cell in response to a value of P/I or I/P, and at least one sensor configured to measure net electrical power entering or exiting the flow battery system, and an amount of electrical current passing through the whole cell. I is the electrical power passing through the whole cell. Pis net electrical power exiting the system in a discharging mode, and Pis net electrical power entering the system in a charging mode.

Flow batteries having adjustable circulation rate capabilities and methods associated therewith

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.

Coordinatively saturated titanium (IV) coordination compounds containing catecholate ligands can be desirable active materials for flow batteries and other electrochemical energy storage systems. Such coordination compounds can be formed advantageously via an intermediate composition containing a coordinatively unsaturated titanium (IV) coordination compound. More specifically, such compositions can include a coordinatively unsaturated titanium (IV) coordination compound having a coordination number of 5 or less and containing two catecholate ligands, wherein the composition is substantially free of non-ligated catechol compound. Methods for forming the coordinatively unsaturated titanium (IV) coordination compounds can include: combining titanium tetrachloride and a catechol compound in an aprotic solvent to form a reaction mixture, and reacting the titanium tetrachloride with the catechol compound in an absence of base to form a coordinatively unsaturated titanium (IV) coordination compound having a coordination number of 5 or less and containing two catecholate ligands and that is insoluble in the reaction mixture.

Coordinatively unsaturated titanium catecholate complexes and processes associated therewith

Productive electrochemical reactions can often occur most effectively in proximity to a separator dividing an electrochemical cell into two half-cells. Parasitic reactions can often occur at locations more removed from the separator. Parasitic reactions are generally undesirable in flow batteries and other electrochemical systems, since they can impact operating performance. Flow batteries having a decreased incidence of parasitic reactions can include, a first half-cell containing a first electrode, a second half-cell containing a second electrode, a separator disposed between the first half-cell and the second half-cell and contacting the first and second electrodes, a first bipolar plate contacting the first electrode, and a second bipolar plate contacting the second electrode, where a portion of the first electrode or the first bipolar plate contains a dielectric material. The first electrode and the first bipolar plate still define a contiguous electrically conductive pathway when containing the dielectric material.

Mitigation of parasitic reactions within flow batteries

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.

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Maynard, MA, United States of America

Adam Morris-Cohen