Method of recovering materials forming fuel cell stack

Patent metadata

Field	Value
Publication number	US-2021296658-A1
Application number	US-201917261132-A
Country	US
Kind code	A1
Filing date	Jun 4, 2019
Priority date	Jul 17, 2018
Publication date	Sep 23, 2021
Grant date	—

Abstract

To recover materials forming a fuel cell stack by an easy method.Provided is a method of recovering, from a fuel cell stack having a stack structure including a plurality of fuel cells stacked, materials forming the fuel cell stack, the fuel cells each including a membrane electrode assembly and two separators holding the membrane electrode assembly therebetween, the separators each being provided with a gas flow channel configured to supply a raw material gas to the membrane electrode assembly, the method including: a first step of supplying a solvent or a solvent and a reagent to the fuel cell stack through the gas flow channel, collecting the solvent which contains a material, and recovering the material from the collected solvent; and a second step of subjecting the fuel cell stack after the first step to a heat treatment to obtain a molten liquid or gas and recovering a material from the molten liquid or gas, the materials recovered including materials forming the membrane electrode assembly and the separators.

First claim

1 . A method of recovering, from a fuel cell stack ( 100 ) having a stack structure including a plurality of fuel cells ( 10 ) stacked, materials forming the fuel cell stack ( 100 ),
the fuel cells ( 10 ) each including a membrane electrode assembly ( 14 ) and two separators ( 15 ) holding the membrane electrode assembly ( 14 ) therebetween, the separators ( 15 ) each being provided with a gas flow channel ( 25 ) configured to supply a raw material gas to the membrane electrode assembly ( 14 ), the method comprising: a first step of supplying a solvent or a solvent and a reagent to the fuel cell stack ( 100 ) through the gas flow channel ( 25 ), collecting the solvent which contains a material, and recovering the material from the collected solvent; and a second step of subjecting the fuel cell stack ( 100 ) after the first step to a heat treatment to obtain a molten liquid and recovering a material from the molten liquid, the materials recovered including materials forming the membrane electrode assembly ( 14 ) and the separators ( 15 ).

2 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 1 , wherein the materials recovered include a precious metal forming the membrane electrode assembly ( 14 ) or the separators ( 15 ), a proton conductive polymer, an organic compound ( 14 ), or a fluororesin forming the membrane electrode assembly ( 14 ), or a metal other than the precious metal forming the separators ( 15 ).

3 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 2 , wherein the first step (S 11 ) comprises the steps of:
supplying an oxidant and a reductant as the reagents and an electrolytic solution as the solvent to the gas flow channel ( 25 ), collecting the electrolytic solution which contains the precious metal, and recovering the precious metal from the collected electrolytic solution; and supplying an alcohol solution as the solvent to the gas flow channel ( 25 ), collecting the alcohol solution which contains the proton conductive polymer, and recovering the proton conductive polymer from the collected alcohol solution.

4 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 3 , wherein
the oxidant is ozone, the reductant comprises hydrogen, carbon monoxide, sulfur dioxide, or a mixture thereof, and the precious metal comprises gold, silver, platinum, palladium, rhodium, iridium, ruthenium, or osmium.

5 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 3 , wherein the first step (S 11 ) further comprises a step of supplying an aprotic solvent as the solvent to the gas flow channel ( 25 ), collecting the aprotic solvent which contains the organic compound, and recovering the organic compound from the collected aprotic solvent.

6 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 5 , wherein in the second step (S 12 ), the fuel cell stack is subjected to a heat treatment at a temperature of 300° C. or higher to obtain a molten liquid, and the fluororesin or the metal other than the precious metal is recovered from the molten liquid.

7 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 2 , wherein
the proton conductive polymer comprises a perfluorosulfonic acid polymer, the organic compound comprises polyvinylidene fluoride, the fluororesin comprises a polytetrafluoroethylene, and the metal other than the precious metal comprises iron, chromium, nickel, or titanium.

8 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 4 , wherein the first step (S 11 ) further comprises a step of supplying an aprotic solvent as the solvent to the gas flow channel ( 25 ), collecting the aprotic solvent which contains the organic compound, and recovering the organic compound from the collected aprotic solvent.

9 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 8 , wherein in the second step (S 12 ), the fuel cell stack is subjected to a heat treatment at a temperature of 300° C. or higher to obtain a molten liquid, and the fluororesin or the metal other than the precious metal is recovered from the molten liquid.

10 . The method of recovering materials forming a fuel cell stack ( 100 ) according to claim 9 , wherein
the proton conductive polymer comprises a perfluorosulfonic acid polymer, the organic compound comprises polyvinylidene fluoride, the fluororesin comprises a polytetrafluoroethylene, and the metal other than the precious metal comprises iron, chromium, nickel, or titanium.

Assignees

• Bosch Gmbh Robert

Inventors

• Takamuku Shogo
• Baldizzone Claudio
• Oshikawa Katsuhiko

Classifications

• B09B3/70

  Chemical treatment, e.g. pH adjustment or oxidation (involving an extraction step B09B3/80) · CPC title

• B09B3/40

  involving thermal treatment, e.g. evaporation (processes using mineral binders involving a melting or softening step B09B3/29; involving radiation B09B3/50) · CPC title

• C22B7/006

  Wet processes · CPC title

• H01M8/008 Primary

  Disposal or recycling of fuel cells · CPC title

• C22B7/003

  only remelting, e.g. of chips, borings, turnings; apparatus used therefor · CPC title