Redox flow secondary battery and electrolyte membrane for redox flow secondary battery

Patent metadata

Field	Value
Publication number	US-2017271698-A1
Application number	US-201715617676-A
Country	US
Kind code	A1
Filing date	Jun 8, 2017
Priority date	Dec 28, 2011
Publication date	Sep 21, 2017
Grant date	—

Abstract

The problem addressed by the present invention is to obtain an electrolyte membrane that, as an electrolyte membrane for a redox flow secondary battery, is able to suppress the ion permeability of an active substance without detracting from proton (H+) permeability, has superior ion-selective permeability, has low electrical resistivity, and has superior current efficiency. The present invention solves the abovementioned problem by means of the electrolyte membrane for a redox flow secondary battery containing a perfluorocarbon sulfonic acid resin having a specific structure and an equivalent weight (EW), and the ion conductivity being adjusted to a predetermined range.

First claim

1 . A redox flow secondary battery comprising an electrolytic bath comprising:
a positive electrode cell chamber comprising a positive electrode composed of a carbon electrode; a negative electrode cell chamber comprising a negative electrode composed of a carbon electrode; and an electrolyte membrane as a diaphragm to separate the positive electrode cell chamber and the negative electrode cell chamber, wherein the positive electrode cell chamber comprises a positive electrode electrolyte solution comprising a positive electrode active substance; and the negative electrode cell chamber comprises a negative electrode electrolyte solution comprising a negative electrode active substance; wherein the redox flow secondary battery charges and discharges based on changes in valences of the positive electrode active substance and the negative electrode active substance in the electrolyte solutions; wherein the electrolyte membrane comprises an ion-exchange resin composition comprising a perfluorocarbonsulfonic acid resin having a structure represented by the following formula (1):
—[CF 2 —CF 2 ] a —[CF 2 —CF(—O—(CF 2 ) m —SO 3 H)] g —  (1)

 wherein a and g represent numbers satisfying 0≦a<1, 0<g≦1, and a+g=1; and m represents an integer of 1 to 6; wherein the perfluorocarbonsulfonic acid resin has an equivalent weight EW (a dry mass in grams per equivalent of ion-exchange groups) of 250 to 1,500 g/eq; and wherein the electrolyte membrane has an ionic conductivity at 110° C. at a relative humidity of 50% RH of 0.05 S/cm or higher, and wherein the electrolyte membrane does not comprise a reinforcing material.

2 . The redox flow secondary battery according to claim 1 , wherein the perfluorocarbonsulfonic acid resin has an equivalent weight EW (a dry mass in grams per equivalent of ion-exchange groups) of 250 to 700 g/eq.

3 . The redox flow secondary battery according to claim 1 , wherein the positive electrode electrolyte solution and the negative electrode electrolyte solution are sulfuric acid electrolyte solutions comprising vanadium.

4 . The redox flow secondary battery according to claim 1 , wherein the electrolyte membrane has an equilibrium moisture content of 5 to 80% by mass.

5 . The redox flow secondary battery according to claim 2 , wherein the electrolyte membrane has an equilibrium moisture content of 5 to 80% by mass.

6 . The redox flow secondary battery according to claim 1 , wherein the ion-exchange resin composition comprises 0.1 to 20 parts by mass of a polyphenylene ether resin and/or a polyphenylene sulfide resin with respect to 100 parts by mass of the perfluorocarbonsulfonic acid resin.

7 . The redox flow secondary battery according to claim 2 , wherein the ion-exchange resin composition comprises 0.1 to 20 parts by mass of a polyphenylene ether resin and/or a polyphenylene sulfide resin with respect to 100 parts by mass of the perfluorocarbonsulfonic acid resin.

Assignees

• Asahi Chemical Ind

Inventors

• Kato Akihiro
• Miyake Naoto

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/188

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

• H01M8/1039 Primary

  halogenated, e.g. sulfonated polyvinylidene fluorides · CPC title

• H01M8/20

  Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence) · CPC title

• H01M8/1023 Primary

  having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes · CPC title