Reverse polarity refresh method and redox flow battery system

Patent metadata

Field	Value
Publication number	US-2022200035-A1
Application number	US-202117643466-A
Country	US
Kind code	A1
Filing date	Dec 9, 2021
Priority date	Dec 22, 2020
Publication date	Jun 23, 2022
Grant date	—

Abstract

A redox flow battery system comprising a catholyte in fluid communication with a cathode, an anolyte in fluid communication with an anode, a membrane in fluid communication with the catholyte and the anolyte, and positive and negative terminals in contact with a power supply and a load. The positive and negative terminals configured to charge the redox flow battery in an opposite direction such that the anolyte is oxidized and the catholyte is reduced. The anolyte and the catholyte are kept separate and never mixed.

First claim

What is claimed is:

1 . A process for refreshing a redox flow battery system, the process comprising:
providing a redox flow battery, the redox flow battery comprising:
a set of terminals connectable to a power supply and a load;
a catholyte in fluid communication with a cathode;
an anolyte in fluid communication with an anode; and
a membrane in fluid communication with the catholyte and the anolyte;
partially discharging the redox flow battery; reversing polarity of the set of terminals of the redox flow battery; and charging the redox flow battery in an opposite direction such that the anolyte is oxidized and the catholyte is reduced.

2 . The process of claim 1 , wherein the redox flow battery system comprises an all-iron redox flow battery, an iron-chromium redox flow battery, or an all-vanadium redox flow battery.

3 . The process of claim 1 , wherein discharging occurs when a state of charge imbalance of the battery reaches about 20% difference from the starting conditions and wherein the step of charging the redox flow battery in an opposite direction is conducted until this difference is less than 5%.

4 . The process of claim 1 , wherein discharging occurs when a pH of the anolyte reaches about 5.0 and wherein the step of charging the redox flow battery in an opposite direction is conducted until the pH of the anolyte reaches about 1.0.

5 . The process of claim 1 , wherein the redox flow battery comprises ascorbic acid in the catholyte only.

6 . The process of claim 1 , wherein the catholyte comprises Fe 2+ , Fe 3+ , V 4+ , or V 5+ .

7 . The process of claim 1 , wherein the anolyte comprises Fe 0 particles, Fe 2+ , Cr 2+ , Cr 3+ , Sn 2+ , Sn 4+ , Mn 2+ , Mn 4+ , Ce 2+ , Ce 3+ , or V 3+ .

8 . The process of claim 6 , wherein the anolyte and the catholyte are kept separate and never mixed.

9 . The process of claim 1 , wherein discharging occurs when a coulombic efficiency of the redox flow battery is below about 80%.

10 . A process for refreshing a redox flow battery system, the process comprising:
providing a redox flow battery, the redox flow battery comprising:
a set of terminals connectable to a power supply and a load;
a catholyte in fluid communication with a cathode;
an anolyte in fluid communication with an anode; and
a membrane in fluid communication with the catholyte and the anolyte;
partially discharging the redox flow battery; and charging the redox flow battery in an opposite direction such that the anolyte is oxidized and the catholyte is reduced, and wherein the anolyte and the catholyte are kept separate and never mixed.

11 . The process of claim 10 , wherein discharging occurs when a coulombic efficiency of the redox flow battery is below about 80%.

12 . The process of claim 10 , wherein the redox flow battery is an all-iron redox flow battery, an iron-chromium redox flow battery, or an all-vanadium redox flow battery.

13 . The process of claim 10 , wherein the catholyte comprises Fe 2+ , Fe 3+ , V 4+ , or V 5+ .

14 . The process of claim 10 , wherein the anolyte comprises Fe 0 particles, Fe 2+ , Cr 2+ , Cr 3+ Sn 2+ , Sn 4+ , Mn 2+ , Mn 4+ , Ce 2+ , or Ce 3+ .

15 . The process of claim 10 , wherein a current density of charging the redox flow battery in the opposite direction is between about ¼ to about ⅓ of a current density of charging the redox flow battery in a forward direction.

16 . A redox flow battery system comprising:
a catholyte in fluid communication with a cathode; an anolyte in fluid communication with an anode; a membrane in fluid communication with the catholyte and the anolyte; and positive and negative terminals in contact with a power supply and a load, the positive and negative terminals configured to charge the redox flow battery in an opposite direction such that the anolyte is oxidized and the catholyte is reduced, and wherein the anolyte and the catholyte are kept separate and never mixed.

17 . The redox flow battery system of claim 16 , wherein the redox flow battery system is an all-iron redox flow battery system or an all-vanadium redox flow battery system.

18 . The redox flow battery system of claim 16 , wherein the redox flow battery is configured to be discharged when a state of charge difference of the anolyte reaches about 20% of the starting condition and wherein charging the redox flow battery in the opposite direction is conducted until the concentration of Fe 3+ in the catholyte is within about 5% of the initial condition.

19 . The redox flow battery system of claim 18 , wherein the redox flow battery is configured to be discharged when a pH of the anolyte reaches about 5.0 and wherein charging the redox flow battery in the opposite direction lowers the pH of the anolyte to about 1.0.

20 . The redox flow battery system of claim 17 , wherein the anolyte or the catholyte comprises ascorbic acid.

Assignees

• Uop Llc

Inventors

• Kender William T

Classifications

• H01M8/188 Primary

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

• H01M2300/0091

  in the form of mixtures · CPC title

• Y02E60/50

  Fuel cells · CPC title