Electrolyte health management for redox flow battery

Patent metadata

Field	Value
Publication number	US-2022123339-A1
Application number	US-202117453993-A
Country	US
Kind code	A1
Filing date	Nov 8, 2021
Priority date	Nov 20, 2018
Publication date	Apr 21, 2022
Grant date	—

Abstract

Methods and systems are provided for a rebalancing reactor of a flow battery system. In one example, a pH of a battery electrolyte may be maintained by the rebalancing reactor by applying a negative potential to a catalyst bed of the rebalancing reactor. A performance of the rebalancing reactor may further be maintained by treating the catalyst bed with deionized water.

First claim

1 . A method for treating a rebalancing reactor of a redox flow battery, comprising:
flowing an electrolyte of the redox flow battery and hydrogen gas generated in the flow battery to the rebalancing reactor, and applying a negative potential to a catalyst bed of the rebalancing reactor while flowing the electrolyte and the hydrogen gas to the rebalancing reactor.

2 . The method of claim 1 , wherein flowing the electrolyte to the rebalancing reactor includes delivering the electrolyte from a battery cell of the redox flow battery to the rebalancing reactor to restore a pH and ferrous iron concentration of the electrolyte.

3 . The method of claim 1 , wherein applying the negative potential to the catalyst bed includes continuously maintaining the negative potential to repel anions.

4 . The method of claim 3 , wherein continuously maintaining the negative potential to repel the anions includes repelling anionic species of the electrolyte.

5 . The method of claim 1 , wherein applying the negative potential to the catalyst bed includes activating an electric device electrically coupled to the catalyst bed by a conductive wire.

6 . The method of claim 5 , wherein activating the electric device includes delivering a voltage to the conductive wire and wherein the conductive wire is incorporated into a catalyst layer of the catalyst bed along a plane of the catalyst layer.

7 . The method of claim 6 , wherein applying the negative potential to the catalyst bed includes delivering a voltage from the electric device to the catalyst bed when the catalyst bed is spiral wound into a cylindrical shape and wherein the conductive wire extends from at least one end of the cylindrical shape along a central axis of rotation of the cylindrical shape.

8 . The method of claim 1 , wherein applying the negative potential to the catalyst bed includes impeding formation of a double diffusion layer at the catalyst bed and increasing a ferrous iron reduction rate.

9 . The method of claim 1 , wherein applying the negative potential to the catalyst bed includes maintaining the negative potential at the catalyst bed continuously during operation of the redox flow battery.

10 . The method of claim 1 , further comprising flushing the catalyst bed with deionized water when a pH of the electrolyte is detected to rise above a threshold pH.

11 . The method of claim 10 , wherein the threshold pH is 4.

12 . The method of claim 10 , wherein flushing the catalyst bed with the deionized water includes flowing the deionized water across the catalyst bed within a housing of the catalyst bed while the redox flow battery is deactivated.

13 . The method of claim 1 , further comprising soaking the catalyst bed in deionized water when an iron reduction rate of the flow battery is detected to fall below a threshold rate.

14 . The method of claim 13 , wherein the threshold rate is 0.6 mol/m 2 hr.

15 . The method of claim 13 , wherein soaking the catalyst bed in the deionized water includes removing the catalyst bed from a housing of the catalyst bed and submerging the catalyst bed in the deionized water and wherein the catalyst bed is submerged in the deionized water at a target temperature over a target duration of time.

16 . The method of claim 15 , wherein the target temperature is at least 80 degrees C. and the target duration of time is at least 60 hours.

17 . The method of claim 1 , wherein applying the negative potential to the catalyst bed includes applying a voltage between −50 mV and −800 mV.

18 . A redox flow battery system, comprising:
a cell receiving electrolyte and hydrogen gas; a rebalancing reactor fluidly coupled to the cell and configured to also receive the electrolyte and the hydrogen gas; and a conductive wire embedded in a catalyst bed of the rebalancing reactor, the conductive wire configured to apply a negative potential to the catalyst bed to impede formation of a double diffusion layer and increase a ferrous iron reduction rate at the catalyst bed.

19 . The redox flow battery system of claim 18 , wherein the catalyst bed is formed of a substrate layer coated with at least one catalyst layer and a spacing layer arranged over the at least one catalyst layer and wherein the catalyst bed is coiled into a cylindrical shape.

20 . The redox flow battery system of claim 19 , wherein the conductive wire is woven in the catalyst layer along a plane of the catalyst layer and wherein the conductive wire is connected to an electrical storage device enabling generation of the negative potential.

Assignees

• Ess Technology Inc

Inventors

• Song Yang
• Mcdonald Timothy J
• Behr Alexandria

Classifications

• H01M8/0693 Primary

  Treatment of the electrolyte residue, e.g. reconcentrating · CPC title

• H01M8/04186

  of liquid-charged or electrolyte-charged reactants · CPC title

• H01M8/04201

  Reactant storage and supply, e.g. means for feeding, pipes · CPC title

• H01M8/188 Primary

  by recharging of redox couples containing fluids; Redox flow type batteries · CPC title

• H01M2300/0005

  Acid electrolytes · CPC title