Polymer electrolyte membrane, membrane-electrode assembly for polymer electrolyte fuel cells and process for producing polymer electrolyte membrane

• US 20060068258A1
• Filed: 10/14/2005
• Published: 03/30/2006
• Est. Priority Date: 04/17/2003
• Status: Active Grant

• Current Assignee: AGC, Inc.
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Kinoshita, Shinji
• Granted Patent: US 8,420,701 B2
• Time in Patent Office: Days
• US Class Current: 429/483
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 4/926 on carbon or graphite
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1053 consisting of layers of polymers with at least one layer being ionically conductive
• CPC Class Codes: H01M 8/1062 characterised by the physical properties of the porous support, e.g. its porosity or thickness
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 20/582 Recycling of unreacted starting or intermediate materials

Abstract

A polymer electrolyte membrane comprises at least one layer of a perforated sheet having many through-holes formed substantially parallel to the thickness direction with an average cross-sectional area per hole ranging from 1×10⁻³ to 20 mm², wherein the numerical aperture based on the through-holes ranges from 30 to 80%, and the through-holes are filled with an ion exchange resin.

Claims

1. A polymer electrolyte membrane characterized by comprising at least one layer of a perforated sheet having many through-holes formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², wherein the numerical aperture based on the through-holes is from 30 to 80%, and an ion exchange resin is filled in the through-holes.

3. The polymer electrolyte membrane according to claim 1, wherein on at least one side of the layer having the ion exchange resin filled in the above perforated sheet, a layer made solely of an ion exchange resin which may be the same or different from the above-mentioned ion exchange resin, is formed.

4. The polymer electrolyte membrane according to claim 1, wherein the perforated sheet is made of a polytetrafluoroethylene, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/perfluoroalkoxyethylene copolymer, a polysulfone, a polyphenylene sulfide, a polyarylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a polyether amide, a polypropylene or a polyethylene.

5. The polymer electrolyte membrane according to claim 1, wherein the perforated sheet has a thickness of from 3 to 50 μ

m.

6. The polymer electrolyte membrane according to claim 1, wherein the ion exchange resin filled in the through-holes is made of a perfluorocarbon polymer having sulfonic groups.

7. The polymer electrolyte membrane according to claim 1, wherein the through-holes are filled with the ion exchange resin and a reinforcing filler, wherein the reinforcing filler is a reinforcing filler of a short fiber form having a fiber diameter of from 0.01 to 20 μ

m, a fiber length of from 1 to 10 mm and an aspect ratio of at least 5.

8. The polymer electrolyte membrane according to claim 3, wherein the through-holes are filled with the ion exchange resin and a reinforcing filler, wherein the reinforcing filler is a reinforcing filler of a short fiber form having an average fiber diameter of from 0.01 to 20 μ

m, an average fiber length of from 1 to 10 mm and an aspect ratio of at least 5, and the layer made solely of an ion exchange resin contains no reinforcing filler.

2. A polymer electrolyte membrane characterized by comprising at least one layer of a perforated sheet comprising a region 1 wherein many through-holes are formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², and the numerical aperture based on the through-holes is from 30 to 80%, and a region 2 which is a peripheral portion of the above region 1 and which has a lower numerical aperture than the above region 1 or has no through-holes, and wherein an ion exchange resin is filled in the through-holes.

9. The polymer electrolyte membrane according to claim 2, wherein on at least one side of the layer having the ion exchange resin filled in the above perforated sheet, a layer made solely of an ion exchange resin which may be the same or different from the above-mentioned ion exchange resin, is formed.

10. The polymer electrolyte membrane according to claim 2, wherein the perforated sheet is made of a polytetrafluoroethylene, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/perfluoroalkoxyethylene copolymer, a polysulfone, a polyphenylene sulfide, a polyarylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a polyether amide, a polypropylene or a polyethylene.

11. The polymer electrolyte membrane according to claim 2, wherein the perforated sheet has a thickness of from 3 to 50 μ

m.

12. The polymer electrolyte membrane according to claim 2, wherein the ion exchange resin filled in the through-holes is made of a perfluorocarbon polymer having sulfonic groups.

13. The polymer electrolyte membrane according to claim 2, wherein the through-holes are filled with the ion exchange resin and a reinforcing filler, wherein the reinforcing filler is a reinforcing filler of a short fiber form having a fiber diameter of from 0.01 to 20 μ

m, a fiber length of from 1 to 10 mm and an aspect ratio of at least 5.

14. The polymer electrolyte membrane according to claim 9, wherein the perforated sheet is made of a polytetrafluoroethylene, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/perfluoroalkoxyethylene copolymer, a polysulfone, a polyphenylene sulfide, a polyarylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a polyether amide, a polypropylene or a polyethylene.

15. The polymer electrolyte membrane according to claim 9, wherein the perforated sheet has a thickness of from 3 to 50 μ

m.

16. The polymer electrolyte membrane according to claim 9, wherein the ion exchange resin filled in the through-holes is made of a perfluorocarbon polymer having sulfonic groups.

17. A membrane-electrode assembly for polymer electrolyte fuel cells, which comprises a polymer electrolyte membrane and a catalyst layer containing a catalyst disposed on each side of the polymer electrolyte membrane, characterized in that the electrolyte membrane comprises at least one layer of a perforated sheet having many through-holes formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², wherein the numerical aperture based on the through-holes is from 30 to 80%, and an ion exchange resin is filled in the through-holes.

19. The membrane-electrode assembly for polymer electrolyte fuel cells according to claim 17, wherein on at least one side of the layer having the ion exchange resin filled in the above perforated sheet, a layer made solely of an ion exchange resin which may be the same or different from the above-mentioned ion exchange resin, is formed.

20. The membrane-electrode assembly for polymer electrolyte fuel cells according to claim 17, wherein the perforated sheet is made of a polytetrafluoroethylene, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/perfluoroalkoxyethylene copolymer, a polysulfone, a polyphenylene sulfide, a polyarylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a polyether amide, a polypropylene or a polyethylene.

21. The membrane-electrode assembly for polymer electrolyte fuel cells according to claim 17, wherein the through-holes are filled with the ion exchange resin and a reinforcing filler, wherein the reinforcing filler is a reinforcing filler of a short fiber form having a fiber diameter of from 0.01 to 20 μ

m, a fiber length of from 1 to 10 mm and an aspect ratio of at least 5.

18. A membrane-electrode assembly for polymer electrolyte fuel cells, which comprises a polymer electrolyte membrane and a catalyst layer containing a catalyst disposed on each side of the polymer electrolyte membrane, characterized in that the electrolyte membrane comprises at least one layer of a perforated sheet comprising a region 1 wherein many through-holes are formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², and the numerical aperture based on the through-holes is from 30 to 80%, and a region 2 which is a peripheral portion of the above region 1 and which has a lower numerical aperture than the above region 1 or has no through-holes, and wherein an ion exchange resin is filled in the through-holes.

22. The membrane-electrode assembly for polymer electrolyte fuel cells according to claim 18, wherein on at least one side of the layer having the ion exchange resin filled in the above perforated sheet, a layer made solely of an ion exchange resin which may be the same or different from the above-mentioned ion exchange resin, is formed.

23. The membrane-electrode assembly for polymer electrolyte fuel cells according to claim 18, wherein the perforated sheet is made of a polytetrafluoroethylene, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/perfluoroalkoxyethylene copolymer, a polysulfone, a polyphenylene sulfide, a polyarylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a polyether amide, a polypropylene or a polyethylene.

24. The membrane-electrode assembly for polymer electrolyte fuel cells according to claim 18, wherein the through-holes are filled with the ion exchange resin and a reinforcing filler, wherein the reinforcing filler is a reinforcing filler of a short fiber form having a fiber diameter of from 0.01 to 20 μ

m, a fiber length of from 1 to 10 mm and an aspect ratio of at least 5.

25. A process for producing a polymer electrolyte membrane reinforced by a perforated sheet, characterized by applying a coating fluid containing an ion exchange resin to a perforated sheet having many through-holes formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², wherein the numerical aperture based on the through-holes is from 30 to 80%, to fill the through-holes with the ion exchange resin.

29. The process for producing a polymer electrolyte membrane according to claim 25, wherein on at least one side of the layer having the ion exchange resin filled in the perforated sheet, a layer made solely of an ion exchange resin which may be the same or different from the above ion exchange resin, is formed.

30. The process for producing a polymer electrolyte membrane according to claim 25, wherein the perforated sheet is made of a polytetrafluoroethylene, a tetrafluoroethylene/hexafluoropropylene copolymer, a tetrafluoroethylene/perfluoroalkoxyethylene copolymer, a polysulfone, a polyphenylene sulfide, a polyarylate, a polyether sulfone, a polyether ether ketone, a polyether imide, a polyether amide, a polypropylene or a polyethylene.

26. A process for producing a polymer electrolyte membrane reinforced by a perforated sheet, characterized by heat pressing a membrane made of an ion exchange resin to a perforated sheet having many through-holes formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², wherein the numerical aperture based on the through-holes is from 30 to 80%, to inject and fill the ion exchange resin in the through-holes.

27. A process for producing a polymer electrolyte membrane reinforced by a perforated sheet, characterized by applying a coating liquid containing an ion exchange resin to a perforated sheet comprising a region 1 wherein many through-holes are formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², and the numerical aperture based on the through-holes is from 30 to 80%, and a region 2 which is a peripheral portion of the region 1 and which has a lower numerical aperture than the region 1 or has no through-holes, to fill the through-holes with the ion exchange resin.

28. A process for producing a polymer electrolyte membrane reinforced by a perforated sheet, characterized by heat pressing a membrane made of an ion exchange resin to a perforated sheet comprising a region 1 wherein many through-holes are formed substantially in parallel to the thickness direction with an average cross-sectional area per hole of from 1×

10<sup>−

3</sup> to 20 mm², and the numerical aperture based on the through-holes is from 30 to 80%, and a region 2 which is a peripheral portion of the region 1 and which has a lower numerical aperture than the region 1 or has no through-holes, to inject and fill the ion exchange resin in the through-holes.