Electrochemical systems incorporating in situ spectroscopic determination of state of charge and methods directed to the same

Patent metadata

Field	Value
Publication number	US-10153502-B2
Application number	US-201514963147-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Dec 8, 2014
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

State of charge determination within electrochemical systems, such as flow batteries, can often be difficult to measure, particularly in an in situ manner. Methods for assaying the condition of an electrochemical system can include: interacting electromagnetic radiation with a first electrolyte solution at a location within the electrochemical system, the electromagnetic radiation being delivered through an optical material configured to exhibit attenuated total reflectance at an interface between the optical material and the first electrolyte solution; receiving at a detector electromagnetic radiation that has interacted with the first electrolyte solution via one or more attenuated total reflectances within the optical material; and measuring an absorbance of at least one of an oxidized form or a reduced form of a first coordination compound within the first electrolyte solution via the electromagnetic radiation that is received at the detector.

First claim

What is claimed is the following:

1. A method comprising:
providing an electrochemical system containing a first electrolyte solution in contact with a first electrode, the first electrolyte solution comprising a first coordination compound having an oxidized form and a reduced form;
interacting electromagnetic radiation with the first electrolyte solution at a location within the electrochemical system, the electromagnetic radiation being delivered through an optical material configured to exhibit attenuated total reflectance at an interface between the optical material and the first electrolyte solution;
wherein the optical material has a higher index of refraction than does the first electrolyte solution;
receiving at a detector electromagnetic radiation that has interacted with the first electrolyte solution via one or more attenuated total reflections within the optical material; and
measuring an absorbance of at least one of the oxidized form or the reduced form of the first coordination compound with the electromagnetic radiation that is received at the detector;
wherein the electrochemical system comprises a flow battery.

2. The method of claim 1 , further comprising:
determining a state of charge of the first electrolyte solution in the electrochemical system.

3. The method of claim 2 , further comprising:
adjusting the first electrolyte solution based upon the state of charge.

4. The method of claim 3 , wherein adjusting the first electrolyte solution comprises at least one of reconditioning or rebalancing the first electrolyte solution, diluting the first electrolyte solution, adding a further amount of the first coordination compound to the first electrolyte solution, increasing a current passing through the first electrolyte solution, decreasing a current passing through the first electrolyte solution, or any combination thereof.

5. The method of claim 2 , further comprising:
determining a concentration of at least one of the oxidized form or the reduced form of the first coordination compound based upon the absorbance measured at the detector.

6. The method of claim 1 , wherein the electromagnetic radiation is interacted with the first electrolyte solution external to a cell defining the flow battery.

7. The method of claim 1 , wherein the electromagnetic radiation is interacted with the first electrolyte solution in proximity to the first electrode.

8. The method of claim 1 , wherein the optical material is selected from the group consisting of sapphire, germanium, fused silica, quartz, cubic zirconia, zinc selenide, diamond, and any combination thereof.

9. The method of claim 1 , wherein the first coordination compound has a molar absorptivity constant of at least about 100 M −1 cm −1 .

10. The method of claim 9 , wherein a product of concentration and molar absorptivity constant of the first coordination compound in the first electrolyte solution is at least about 100 cm −1 .

11. The method of claim 1 , wherein the optical material is configured to provide between 1 and about 6 attenuated total reflectances at the interface with the first electrolyte solution.

12. The method of claim 1 , wherein the electromagnetic radiation comprises one or more wavelengths ranging between about 180 nm and about 800 nm.

13. The method of claim 1 , wherein the absorbance is measured at least at an isosbestic point exhibited by the oxidized form and the reduced form of the first coordination compound.

14. The method of claim 1 , wherein a depth of penetration of the electromagnetic radiation into the first electrolyte solution ranges between about 0.05 microns and about 2 microns.

15. A method comprising:
providing an electrochemical system containing a first electrolyte solution in contact with a first electrode, the first electrolyte solution comprising a first coordination compound having an oxidized form and a reduced form;
interacting electromagnetic radiation with the first electrolyte solution at a location within the electrochemical system, the electromagnetic radiation being delivered through an optical material configured to exhibit attenuated total reflectance at an interface between the optical material and the first electrolyte solution;
wherein the optical material has a higher index of refraction than does the first electrolyte solution;
receiving at a detector electromagnetic radiation that has interacted with the first electrolyte solution via one or more attenuated total reflections within the optical material; and
measuring an absorbance of at least one of the oxidized form or the reduced form of the first coordination compound with the electromagnetic radiation that is received at the detector;
wherein the electromagnetic radiation is absorbed by only one of the oxidized form or the reduced form of the first coordination compound.

16. The method of claim 1 , wherein the electromagnetic radiation is absorbed by both the oxidized form and the reduced form of the first coordination compound.

17. An electrochemical system comprising:
a first electrolyte solution in contact with a first electrode, the first electrolyte solution comprising a first coordination compound having an oxidized form and a reduced form;
a source of electromagnetic radiation;
an optical material establishing optical communication between the source of electromagnetic radiation and the first electrolyte solution;
wherein the optical material is configured to exhibit attenuated total reflectance at an interface between the optical material and the first electrolyte solution, the optical material having a higher index of refraction than does the first electrolyte solution; and
a detector configured to receive electromagnetic radiation from the optical material that has interacted with the first electrolyte solution via one or more attenuated total reflections at the interface between the optical material and the first electrolyte solution;
wherein the electrochemical system comprises a flow battery.

18. The electrochemical system of claim 17 , wherein the optical material establishes optical communication with the first electrolyte solution outside a cell defining the flow battery.

19. The electrochemical system of claim 17 , wherein the optical material establishes optical communication with the first electrolyte solution in proximity to the first electrode.

20. The electrochemical system of claim 17 , wherein the optical material is selected from the group consisting of sapphire, germanium, fused silica, quartz, cubic zirconia, zinc selenide, diamond, and any combination thereof.

Assignees

• Lockheed Martin Energy Llc

Inventors

• Pijpers Joseph Johannes Henricus

Classifications

• G01N21/8507 Primary

  Probe photometers, i.e. with optical measuring part dipped into fluid sample · CPC title

• H01M8/04477 Primary

  of the electrolyte · CPC title

• H01M8/04604

  Power, energy, capacity or load · CPC title

• G01R31/3606

  Physics · mapped topic

• G01N21/552

  Attenuated total reflection · CPC title