Cost-efficient high energy density redox flow battery

Patent metadata

Field	Value
Publication number	US-2020052319-A1
Application number	US-201916536237-A
Country	US
Kind code	A1
Filing date	Aug 8, 2019
Priority date	Aug 10, 2018
Publication date	Feb 13, 2020
Grant date	—

Abstract

Methods and systems are provided for a redox flow battery system. In one example, the redox flow battery is adapted with an additive included in a battery electrolyte and an anion exchange membrane separator dividing positive electrolyte from negative electrolyte. An overall system cost of the battery system may be reduced while a storage capacity, energy density and performance may be increased.

First claim

1 . A redox flow battery system, comprising:
a battery cell with a positive electrolyte and a negative electrolyte, the positive electrolyte in contact with a positive electrode and the negative electrolyte in contact with a negative electrode; and a membrane separator arranged between the negative electrolyte and positive electrolyte, the membrane separator formed from an anion exchange membrane (AEM) configured to maintain a charge balance of the battery cell and increase an energy density of the redox flow battery system.

2 . The redox flow battery system of claim 1 , wherein the AEM transports anions between the positive electrolyte and negative electrolyte.

3 . The redox flow battery system of claim 2 , wherein the AEM blocks passage of cations between the positive electrolyte and negative electrolyte.

4 . The redox flow battery system of claim 1 , wherein the positive electrolyte and the negative electrolyte are formed exclusively from a redox active species and free of supporting, redox inactive materials.

5 . The redox flow battery system of claim 4 , wherein a concentration of the redox active species is increased by two times or more when the membrane separator is formed from the AEM.

6 . The redox flow battery system of claim 4 , wherein a solubility of the redox active species is higher when the electrolyte is formed exclusively from redox active species than when the electrolyte includes both the redox active species and the supporting, redox inactive materials.

7 . The redox flow battery system of claim 1 , wherein the anions flow across the AEM in response to a charge imbalance between the positive electrolyte and the negative electrolyte.

8 . The redox flow battery system of claim 1 , wherein both a volume of positive electrolyte and a volume of negative electrolyte in the redox flow battery system are decreased when the membrane separator is formed from the AEM than when the membrane separator is not formed from the AEM.

9 . The redox flow battery system of claim 1 , wherein the AEM is formed from a polymer network configured with high anion selectivity.

10 . The redox flow battery system of claim 1 , wherein the AEM is formed from a covalent organic framework.

11 . The redox flow battery system of claim 1 , wherein the AEM includes pH resistant functional groups.

12 . The redox flow battery system of claim 1 , wherein the AEM is fabricated by one of grafting, surface coating, solvent, casting, and conformal coating.

13 . The redox flow battery system of claim 1 , wherein the AEM is formed of a pre-fabricated, commercially available material.

14 . A method for a redox flow battery system comprising;
plating a metal from an electrolyte solution onto a negative electrode during charging of the redox flow battery system; deplating the metal from the negative electrode into the electrolyte solution during discharging of the redox flow battery system; and transporting anions across an anion exchange membrane separator positioned in the electrolyte solution, the anion exchange membrane separator configured to separate a negative electrode compartment from a positive electrode compartment of the redox flow battery system.

15 . The method of claim 14 , wherein transporting anions includes transporting anions without transporting cations or complexes across the separator.

16 . The method of claim 14 , wherein transporting anions across the anion exchange membrane separator includes transporting anions from a region of the redox flow battery system of lower overall positive bias to a region of higher overall positive bias.

17 . The method of claim 14 , further comprising forming the electrolyte solution from only redox active species and no supporting salts and wherein forming the electrolyte solution from only the redox active species includes increasing a concentration of the redox active species relative to when the supporting salts are present in the electrolyte solution.

18 . An iron redox flow battery comprising;
an electrolyte formed from iron chloride complexes in aqueous solution in contact with a positive electrode and a negative electrode; and an anion exchange membrane separator positioned between the positive electrode and negative electrode and in contact with the electrolyte, the anion exchange membrane separator configured to selectively interact with chloride anions from the iron chloride complexes.

19 . The iron redox flow battery of claim 18 , wherein an energy density of the iron redox flow battery is at least two times higher when the anion exchange membrane separator is implemented in the iron redox flow battery.

20 . The iron redox flow battery of claim 18 , wherein the anion exchange membrane separator blocks cross-over of iron cations from the iron chloride complexes between a positive electrode compartment housing the positive electrode and a negative electrode compartment housing the negative electrode.

Assignees

• Ess Technology Inc

Inventors

• Song Yang
• Evans Craig E

Classifications

• H01M8/188 Primary

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

• H01M4/368

  Liquid depolarisers · CPC title

• H01M8/02

  Details (electrodes H01M4/86 - H01M4/98) · CPC title

• H01M4/582

  Halogenides · CPC title

• H01M8/1018

  Polymeric electrolyte materials · CPC title