Fuel cell

Patent metadata

Field	Value
Publication number	US-9160020-B2
Application number	US-201013259495-A
Country	US
Kind code	B2
Filing date	Jan 19, 2010
Priority date	Mar 31, 2009
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

An electrode structure 15 is received in a joint portion of frames 13, 14 . A first gas diffusion layer 19 and a first gas passage forming member 21 are arranged on a first surface of the electrode structure 15 . A second gas diffusion layer 20 and a second gas passage forming member 22 are formed on a second surface of the electrode structure 15 . A separator 23 is joined with a surface of the frame 13 and a surface of the gas passage forming member 21 . A separator 24 is joined with a surface of the frame 14 and a surface of the gas passage forming member 22 . A water passage 28 is formed between a flat plate 25 of the gas passage forming member 22 and the separator 24 . The water passage 28 has a depth set to a value smaller than depth of a gas passage T 2 of the gas passage forming member 22 . Generated water is introduced from the gas passage T 2 of the gas passage forming member 22 to the water passage 28 through capillary action via communication holes 29 . The generated water in the water passage 28 is moved to a downstream side of the water passage 28 by pressure caused by oxidization gas. This prevents corrosion of the cathode side electrode catalyst layer and improves durability of the anode side gas passage forming member. As a result, a fuel cell capable of preventing decrease of power generation is provided.

First claim

The invention claimed is:

1. A fuel cell comprising:
a first electrode catalyst layer laid on an anode side surface of an electrolyte membrane;
a second electrode catalyst layer laid on a cathode side surface of the electrolyte membrane;
a first gas passage forming member that is laid on a surface of the first electrode catalyst layer and has a first gas passage for supplying fuel gas;
a second gas passage forming member that is laid on a surface of the second electrode catalyst layer and has a second gas passage for supplying oxidization gas;
a first separator arranged in the first gas passage forming member;
a second separator laid on a surface of the second gas passage forming member;
an introducing passage and a discharging passage for the fuel gas; and
an introducing passage and a discharging passage for the oxidization gas;
wherein the second gas passage forming member is configured by a flat plate, a plurality of first projections that are formed on the flat plate to form the second gas passage, and a plurality of second projections that are formed on the flat plate to form the water passage, and the first projections and the second projections project toward the opposite sides of the second gas passage forming member,
a water passage is formed between a surface of the flat plate of the second gas passage forming member and a backside of the second separator corresponding to the second gas passage forming member,
the water passage and the second gas passage are formed on the opposite sides of the second gas passage forming member and communicate with each other through a communication hole formed by each of the first projections that are shaped by cutting and raising in the second gas passage forming member,
the water passage has a depth set to a value smaller than depth of the second gas passage, and
water drawn from the second gas passage into the water passage through capillary action via the communication holes is drained to the oxidation gas discharging passage by pressure caused by the oxidization gas flowing in the second gas passage.

2. The fuel cell according to claim 1 , wherein the water passage extends continuously along the entire length from an end of the second gas passage forming member at a side corresponding to the oxidation gas introducing passage to an end of the second gas passage forming member at another side corresponding to the fuel gas discharging passage.

3. The fuel cell according to claim 1 , wherein a water drainage promoting member formed by a porous body having continuous pores is received in a portion of the second gas passage forming member in which the oxidation gas discharging passage and the water passage are joined together, and any one of the following configurations is selected: a configuration in which the average pore diameter of the continuous pores of the water drainage promoting member is set to a value smaller than the depth of the water passage; a configuration in which wettability of the continuous pores of the water drainage promoting member is set to a value higher than wettability of the water passage; and a configuration in which hydration property of the continuous pores of the water drainage promoting member is set to a value greater than hydration property of the water passage.

4. The fuel cell according to claim 1 ,
wherein the second gas passage forming member is configured by the flat plate, first projections that are formed on the flat plate to form the second gas passage, and second projections that are formed on the flat plate to form the water passage,
the first projections are shaped by cutting and raising toward the second electrode catalyst layer in such a manner that the first projections are arranged separately from one another at a plurality of positions on the flat plate material,
the second projections project toward the second separator and are shaped through extrusion in such a manner that the second projections are arranged separately from one another at a plurality of positions on the flat plate material, and
the communication holes are holes formed in the flat plate by the cutting and raising of the first projections.

5. The fuel cell according to claim 4 ,
wherein the first projections are shaped like bridges,
the communication holes are each formed in such a manner as to extend through the corresponding first projection in a direction perpendicular to a gas flow direction and have openings at two positions, which are a left end and a right end of the first projection as viewed in the gas flow direction,
each pair of the first projections are adjacent to each other in the direction perpendicular to the gas flow direction and, in the pair of the first projections, the first projection located upstream in the gas flow direction has a downstream end adjacent to an upstream end of the first projection located downstream in the gas flow direction, and
the second projections are arranged adjacent to the corresponding first projections from a downstream side of the gas flow direction.

6. The fuel cell according to claim 4 ,
wherein the first projections and the second projections are arranged alternately in the direction perpendicular to the gas flow direction and configure a plurality of row-like projection groups,
the projection groups are arranged parallel to one another and spaced apart at predetermined intervals in the gas flow direction,
a band-like flat plate portion is formed between each adjacent pair of the rows of the projection groups with the water passage formed between the flat plate portions and the second separator, and
the communication holes are each formed in such a manner as to have an opening facing upstream in the gas flow direction in the corresponding first projection.

7. The fuel cell according to claim 1 ,
wherein the second gas passage forming member is configured by the flat plate and first projections that are formed on the flat plate to form the second gas passage,
the first projections are shaped by cutting and raising toward the second electrode catalyst layer in such a manner that the first projections are arranged separately from one another at a plurality of positions on the flat plate material,
the second separator includes second projections projecting toward the flat plate to form the water passage between the second separator and the flat plate, the second projections being shaped through extrusion in such a manner that the second projections are arranged separately from one another at a plurality of positions on the second separator, and
the communication holes are holes formed in the flat plate by the cutting and raising of the first projections.

8. The fuel cell according to claim 4 , wherein the first projections are each formed in a semi-cylindrical shape in such a manner that the corresponding communication hole has a semi-circular shape as viewed in a direction perpendicular to a gas flow direction.

9. The fuel cell according to claim 4 , wherein the first projections include two types, which are semi-cylindrical projections and flat table-like projections, the two types of projections being arranged alternately and separately from one another, a surface of each of the flat table-like projections held in contact with the second electrode catalyst layer is a flat surface, and a surface of each of the semi-cylindrical projections held in contact with the second electrode catalyst layer is an arcuate surface.

10. The fuel cell according to claim 1 ,
wherein the second gas passage forming member is configured by the flat plate, first raised portions that are formed on the flat plate and serve as the projections for forming the water passage and the second gas passage, a

Assignees

• Kawajiri Kousuke
• Hashimoto Keiji
• Futami Satoshi
• Kanie Takamasa
• Moteki Kazunari
• Hayashi Tomokazu
• Toyota Auto Body Co Ltd
• Toyota Jidosha Kabushiki Kiasha

Inventors

• Kawajiri Kousuke
• Hashimoto Keiji
• Futami Satoshi
• Kanie Takamasa
• Moteki Kazunari
• Hayashi Tomokazu

Classifications

• H01M8/1004 Primary

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title

• H01M8/021

  Alloys based on iron · CPC title

• Y02E60/521

  Cross-Sectional Technologies · mapped topic

• H01M8/04126

  Humidifying · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title