WO2012035584A1

WO2012035584A1 - Separator for fuel cell and fuel cell

Info

Publication number: WO2012035584A1
Application number: PCT/JP2010/005665
Authority: WO
Inventors: 順朗野々山; 耕太郎池田
Original assignee: トヨタ自動車株式会社
Priority date: 2010-09-16
Filing date: 2010-09-16
Publication date: 2012-03-22
Also published as: JPWO2012035584A1

Abstract

Provided is a separator for a fuel cell, positioned to be in contact with a laminated body including a membrane electrode assembly, comprising: a gas supply path forming section for forming with the laminated body a gas supply path that has a blocked end section on the downstream side in the gas flow direction and which is a gas supply path; a gas discharge path forming section for forming with the laminated body a gas discharge path that has a blocked end section on the upstream side in the gas flow direction and which is a gas discharge path; and a gas travel path forming section for forming with the laminated body a gas travel path that has a smaller cross-sectional area than the gas supply path and the gas discharge path, and which is a gas travel path for making gas inside the gas supply path travel to the gas discharge path.

Description

Fuel cell separator, fuel cell

The present invention relates to a fuel cell separator and a fuel cell.

Generally, a fuel cell such as a polymer electrolyte fuel cell has a separator for separating a fuel gas and an oxidant gas as a reaction gas by a plurality of power generators including an electrolyte membrane and a pair of electrodes (anode and cathode). It is used in the form of a stack structure laminated through. A separator having a surface formed with a flow path forming part such as a groove that forms a flow path for flowing a fluid such as a reaction gas or a cooling medium (for example, a cooling liquid) is known. Yes.

The separator provided with the flow path forming unit includes a flow path on the supply side for circulating a supply gas to be supplied to the membrane electrode assembly, and an exhaust gas discharged from the membrane electrode assembly when stacked. A flow path separated from the flow path on the discharge side for circulating the gas is formed, and the supply gas flowing through the flow path on the supply side is directly discharged without going through the inside of the laminate such as a membrane electrode assembly. What suppresses moving to the flow path on the side is known. (Patent Document 1).

JP 2004-146309 A JP 2004-273392 A JP 2005-327532 A JP 2005-322595 A JP 2007-299657 A JP-A-8-96820

However, in a fuel cell having a configuration in which a supply-side flow path and a discharge-side flow path are separated, liquid such as generated water generated by power generation is discharged from the supply-side flow path or the supply-side flow path. In some cases, it stays in the laminated body in the vicinity of the space between the side flow paths. The staying liquid hinders the diffusion of the gas flowing in from the supply-side flow path in the supply-side flow path or the laminated body, which may reduce the power generation efficiency of the fuel cell.

The present invention has been made to solve the above-described problems, and in a fuel cell having a configuration in which a supply-side flow path and a discharge-side flow path are separated, a supply-side flow path and a membrane electrode are provided. It aims at suppressing the fall of the electric power generation efficiency by a liquid staying in the inside of the laminated body containing a joined body.

In order to solve at least a part of the above problems, the present invention can be realized as the following aspects or application examples.

[Application Example 1]
A separator for a fuel cell disposed in contact with a laminate including a membrane electrode assembly,
A gas supply channel for supplying gas to the membrane electrode assembly, the gas supply channel for forming a gas supply channel having a closed end on the downstream side in the gas flow direction between the laminated body A gas supply flow path forming section;
A gas discharge flow path for discharging gas from the membrane electrode assembly, for forming a gas discharge flow path between the laminated body and a closed end on the upstream side in the gas flow direction. A gas discharge flow path forming section;
One end is connected to the gas supply flow path, the other end is connected to the gas discharge flow path, and a gas movement flow path for moving the gas in the gas supply flow path to the gas discharge path A separator comprising: a gas movement flow path forming portion for forming a gas movement flow path having a smaller cross-sectional area than the gas supply flow path and the gas discharge flow path between the laminated body.

According to this configuration, when the separator is used in a fuel cell in a state where it is in contact with the laminate including the membrane electrode assembly, the separator is in contact between the gas supply flow path and the gas discharge path. In a fuel cell having a configuration in which a supply-side flow path and a discharge-side flow path are separated from each other, a laminate including a supply-side flow path and a membrane electrode assembly It is possible to suppress a decrease in power generation efficiency due to the liquid remaining in the interior.

[Application Example 2]
In the separator described in Application Example 1,
Each of the gas supply flow path forming portion and the gas discharge flow path forming portion has a groove shape extending along a first direction, and both the gas flow directions are in the first direction. , Arranged alternately along the second direction,
The separator further includes
A region formed at the top of the rib formed by the gas supply channel forming part and the gas discharge channel forming part, the rib region extending along the first direction,
The gas movement flow path forming part has a groove shape formed in a straight line, and is formed in the rib region.

According to this configuration, since the separator includes the groove-shaped gas movement flow path forming portion in the rib region, in the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated, It is possible to suppress a decrease in power generation efficiency due to the liquid remaining in the supply-side flow path or the laminate including the membrane electrode assembly.

[Application Example 3]
In the separator described in Application Example 2,
The gas supply flow path forming section and the gas discharge flow path forming section are each a pair of side surface portions extending along a first direction, and a closed surface portion connecting the end portions of the pair of side surface portions, With
The rib regions are respectively formed between the side surface portion of the gas supply channel forming portion and the side surface portion of the gas discharge channel forming portion,
The gas movement flow path forming portion has one end portion in which the position in the first direction is equal to the closing surface portion of the gas supply path forming portion in at least some of the rib regions. To the closed surface portion of the gas discharge path forming portion and the other end portion having the same position in the first direction, and is formed at predetermined intervals along the first direction. , Separator.

According to this configuration, since the gas movement flow path forming portion is formed at predetermined intervals along the first direction, the separator separates the supply-side flow path and the discharge-side flow path. In the fuel cell having the configuration, it is possible to suppress a decrease in power generation efficiency due to the liquid staying in the flow path on the supply side or the laminated body including the membrane electrode assembly.

[Application Example 4]
In the separator described in Application Example 3,
The predetermined interval is an interval in the range of 0.3 to 1.2 mm,
The separator, wherein the gas supply flow path forming part and the gas discharge flow path forming part are alternately arranged so that the distance between them in the second direction is in the range of 0.8 to 2 mm.

According to this configuration, in the separator, the gas movement flow path forming portions are formed at intervals of 0.3 to 1.2 mm along the first direction, and the gas supply flow path forming portion and the gas discharge flow path forming portion are formed. In the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated from each other, the parts are alternately arranged so that the distance between them is in the range of 0.8 to 2 mm. It is possible to suppress a decrease in power generation efficiency due to the liquid staying in the flow path on the side and the laminated body including the membrane electrode assembly.

[Application Example 5]
In the separator according to any one of Application Examples 1 to 4,
The gas movement flow path forming unit is a separator formed such that a cross-sectional area of the gas movement flow path is 1/10 or less of a cross-sectional area of the gas supply path and the gas discharge flow path.

According to this configuration, since the separator includes the gas movement flow path having a cross-sectional area of 1/10 or less of the cross-sectional area of the gas supply path and the gas discharge path, the supply-side flow path and the discharge-side flow path In a fuel cell having a configuration in which a path is separated, it is possible to suppress a decrease in power generation efficiency due to a liquid staying in a supply-side flow path or a laminate including a membrane electrode assembly.

[Application Example 6]
In the separator according to any one of Application Examples 2 to 5,
The gas supply flow path forming portion and the gas discharge flow path forming portion have a groove width in the range of 0.8 to 2 mm and a groove depth in the range of 0.2 to 1 mm, respectively. Formed,
The gas transfer flow path forming portion is a separator formed such that the groove width is in the range of 50 to 200 μm and the groove depth is in the range of 30 to 150 μm.

According to this configuration, the separator has a groove width in the range of 0.8 to 2 mm and a groove depth in the range of 0.2 to 1 mm in the gas supply channel formation unit and the gas discharge channel formation unit. In addition, the gas movement flow path forming portion is formed so that the groove width is in the range of 50 to 200 μm and the groove depth is in the range of 30 to 150 μm. In a fuel cell having a configuration in which a flow path on the discharge side is separated, a reduction in power generation efficiency due to liquid staying inside the flow path on the supply side and the laminate including the membrane electrode assembly is suppressed. Can do.

[Application Example 7]
In the separator according to any one of Application Example 3 to Application Example 6,
The arrangement density of the gas movement flow path forming part in the rib area is higher than the area in contact with the upstream side of the gas supply flow path forming part and the gas discharge flow path forming part. The separator is higher in the area in contact with the downstream side of the discharge flow path forming portion.

According to this configuration, in the separator, the arrangement density of the gas movement flow path forming part formed in the rib region is higher than the area in contact with the upstream side in the gas flow direction of the gas supply flow path forming part and the gas discharge flow path forming part. In the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated, the region in contact with the downstream side is formed to be higher. It is possible to suppress a decrease in power generation efficiency due to the liquid remaining in the laminated body including the electrode assembly.

[Application Example 8]
In the separator according to any one of Application Example 3 to Application Example 7,
The second direction is a vertical direction;
The gas movement flow path forming portion has an upper end side in contact with the side surface portion of the gas supply flow path forming portion and a lower end side in contact with the side surface portion of the gas discharge flow path forming portion among the plurality of rib regions. A separator formed only in the rib region.

According to this configuration, the separator is a rib whose upper end side in the gravity direction is in contact with the side surface portion of the gas supply flow path forming portion and whose lower end side in the gravity direction is in contact with the side surface portion of the gas discharge flow path forming portion among the plurality of rib regions. Since the gas movement flow path forming part is formed only in the region, in the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated, the supply-side flow path and the membrane electrode assembly It is possible to suppress a decrease in power generation efficiency due to the liquid staying inside the laminate including.

[Application Example 9]
In the separator according to any one of Application Example 3 to Application Example 7,
The second direction is a vertical direction;
The gas movement flow path forming part has an upper end side in contact with the side surface part of the gas discharge flow path forming part and a lower end side in contact with the side surface part of the gas supply flow path forming part among the plurality of rib regions. A separator comprising a closing portion for closing a part of the gas movement channel in the rib region.

According to this configuration, the separator has a rib in which the upper end side in the gravity direction is in contact with the side surface portion of the gas discharge flow path forming portion and the lower end side in the gravity direction is in contact with the side surface portion of the gas supply flow path forming portion among the plurality of rib regions. In the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated from each other in the region, the supply-side flow path is provided with a closing portion for closing a part of the gas movement flow path forming portion. It is possible to suppress a decrease in power generation efficiency due to the liquid remaining in the flow path and the laminated body including the membrane electrode assembly.

[Application Example 10]
In the separator according to Application Example 8 or Application Example 9,
The width in the vertical direction of the rib region where the upper end side is in contact with the side surface portion of the gas supply flow path forming portion and the lower end side is in contact with the side surface portion of the gas discharge flow path forming portion is as follows. The separator is wider than the width in the vertical direction of the rib region that is in contact with the side surface portion and the lower end side is in contact with the side surface portion of the gas supply flow path forming portion.

According to this configuration, in the plurality of rib regions, the separator is in the vertical direction of the rib region in which the upper end side is in contact with the side surface portion of the gas supply flow path forming portion and the lower end side is in contact with the side surface portion of the gas discharge flow path forming portion. The width is formed so that the upper end side is in contact with the side surface portion of the gas discharge flow path forming portion and the lower end side is wider than the width in the vertical direction of the rib region in contact with the side surface portion of the gas supply flow path forming portion. In a fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated, the power generation efficiency due to the liquid staying inside the supply-side flow path and the laminate including the membrane electrode assembly Can be suppressed.

[Application Example 11]
In the separator according to any one of Application Example 3 to Application Example 10,
In the rib region, the gas movement flow path forming unit is configured to have the closed surface portion of the gas discharge path forming portion from one end portion of the gas supply path forming portion having the same position in the first direction as the closed surface portion. And a separator that is formed so as to be parallel to each other or cross each other in the entire range between the same position in the first direction and the other end.

According to this configuration, the separator is formed such that the gas movement flow path forming portions are parallel to each other or cross each other in the entire range in the direction along the first direction of the rib region. In the fuel cell having a configuration in which the flow path and the discharge-side flow path are separated, the generation efficiency is reduced due to the liquid remaining in the supply-side flow path and the laminate including the membrane electrode assembly. Suppression can be achieved.

[Application Example 12]
In the separator according to any one of Application Examples 2 to 11,
The gas movement flow path forming unit is a separator having a shape in which a cross-sectional shape of the gas movement flow path is any one of a triangular shape, a quadrangular shape, and a semicircular shape.

According to this configuration, the separator has the gas movement flow path forming portion formed so that the cross-sectional shape of the gas movement flow path is any one of a triangular shape, a quadrangular shape, and a semicircular shape. In the fuel cell having a configuration in which the flow path and the discharge-side flow path are separated, the generation efficiency is reduced due to the liquid remaining in the supply-side flow path and the laminate including the membrane electrode assembly. Suppression can be achieved.

[Application Example 13]
In the separator according to any one of Application Examples 2 to 12,
The gas movement flow path forming part is a separator having a higher hydrophilicity than a contact surface in contact with the separator of the laminate.

According to this configuration, since the separator includes the gas movement flow path forming portion having a higher hydrophilicity than the contact surface in contact with the separator of the laminate, the flow path on the supply side and the flow path on the discharge side are separated. In the fuel cell having the above-described configuration, it is possible to suppress a decrease in power generation efficiency due to the liquid remaining in the flow path on the supply side and the laminated body including the membrane electrode assembly.

[Application Example 14]
The separator according to any one of Application Example 2 to Application Example 12,
In order to cool the fuel cell on the second surface opposite to the first surface on which the gas supply flow path forming section, the gas flow path forming section, and the gas movement flow path forming section are respectively formed. A separator having a liquid flow path forming part for forming a liquid flow path for circulating the liquid.

According to this configuration, the separator has a liquid for cooling the fuel cell on the second surface opposite to the first surface on which the gas flow path forming portion and the gas movement flow path forming portion are respectively formed. Since the liquid flow path forming part for forming the liquid flow path for circulation is provided, it is possible to efficiently suppress the temperature increase of the fuel cell due to the flow path on the supply side and power generation.

[Application Example 15]
A fuel cell,
A laminate including a membrane electrode assembly;
A fuel cell comprising: the separator according to claim 1 disposed on both sides of the laminate.

According to this configuration, even if the fuel cell has a configuration in which the supply-side flow path and the discharge-side flow path are separated inside, the laminated body in the vicinity between the gas supply flow path and the gas discharge path In the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated, the supply-side flow path and the inside of the laminate including the membrane electrode assembly are provided. Therefore, it is possible to suppress a decrease in power generation efficiency due to the liquid staying there.

[Application Example 16]
A fuel cell,
A laminate including a membrane electrode assembly;
A plurality of separators according to claim 14 disposed on both sides of the laminate,
Each of the separators is a fuel cell in which the liquid flow path forming portion is arranged so as to face the liquid flow path forming portion of another separator.

According to this configuration, since the fuel cell is disposed so that the liquid flow path forming part of the separator faces the liquid flow path forming part of the other separator, the liquid for suppressing the temperature rise of the fuel cell The flow path can be easily configured.

[Application Example 17]
In the fuel cell according to Application Example 15 or Application Example 16,
The laminate includes a gas diffusion layer disposed in contact with the membrane electrode assembly,
The fuel cell, wherein the separator is in contact with the gas diffusion layer.

According to this configuration, even if the fuel cell has the gas diffusion layer between the separator and the membrane electrode assembly, the gas flows through the gas diffusion layer in the vicinity between the gas supply channel and the gas discharge channel. In the fuel cell having a configuration in which the supply-side flow path and the discharge-side flow path are separated, the liquid stays inside the supply-side flow path and the laminate including the membrane electrode assembly. By doing so, it is possible to suppress a decrease in power generation efficiency.

The present invention can be realized in various modes. For example, a fuel cell separator, a fuel cell including a fuel cell separator, a fuel cell manufacturing method, a fuel cell system including a fuel cell, and a fuel cell. It can be realized in the form of a moving body such as an automobile equipped with the system.

It is explanatory drawing which shows schematic structure of the fuel cell system in 1st Example of this invention. It is a cross-sectional schematic diagram showing the schematic structure of the single cell in 1st Example. It is explanatory drawing which shows schematic structure of the cathode side separator in 1st Example. It is explanatory drawing which showed the gas supply branch channel groove and gas discharge branch channel groove in 1st Example in perspective. It is explanatory drawing for demonstrating the shape of the gas movement flow-path groove | channel in 1st Example. It is explanatory drawing which showed typically the boundary vicinity of the cathode side separator which is not provided with the gas movement flow path groove | channel as a comparative example, and a gas diffusion layer. It is explanatory drawing which showed typically the boundary vicinity of the cathode side separator and gas diffusion layer which concern on 1st Example. It is explanatory drawing for demonstrating the test result in a 1st test. It is explanatory drawing for demonstrating the test result in a 2nd test. It is explanatory drawing for demonstrating schematic structure of the cathode side separator in the modification of 1st Example. It is explanatory drawing for demonstrating the shape of the gas movement flow path groove | channel in the modification of 1st Example. It is explanatory drawing which shows schematic structure of the cathode side separator in 2nd Example. It is explanatory drawing which showed typically the boundary vicinity of the cathode side separator and gas diffusion layer which concern on 2nd Example. 10 is an explanatory diagram showing a schematic configuration of a cathode separator in Comparative Example 6. FIG. 10 is an explanatory diagram showing a schematic configuration of a cathode separator in Comparative Example 7. FIG. FIG. 16 is an explanatory diagram illustrating a part of a YY cross section of FIG. 15; It is explanatory drawing for demonstrating the test result in a 3rd test. It is explanatory drawing which shows schematic structure of the cathode side separator in 3rd Example. It is explanatory drawing which showed typically the boundary vicinity of the 1st obstruction | occlusion type gas movement flow path groove | channel formed in the cathode side separator, and a gas diffusion layer. It is explanatory drawing which showed typically the boundary vicinity of the 2nd obstruction | occlusion type gas movement flow-path groove | channel formed in the cathode side separator, and a gas diffusion layer. It is explanatory drawing for demonstrating the moving direction of the water | moisture content of the cathode side separator in a comparative example. It is explanatory drawing for demonstrating the movement direction of the water | moisture content of the cathode side separator in a present Example. It is explanatory drawing for demonstrating the test result in a 4th test. It is explanatory drawing for demonstrating schematic structure of the cathode side separator in the modification 1 of 3rd Example. It is explanatory drawing for demonstrating schematic structure of the cathode side separator in the modification 2 of 3rd Example. It is explanatory drawing for demonstrating schematic structure of the cathode side separator in the modification 3 of 3rd Example.

Next, embodiments of the present invention will be described based on examples.

A. First embodiment:
A-1. General configuration of the fuel cell system:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system according to a first embodiment of the present invention. The fuel cell system 10 controls the fuel cell 100, a hydrogen tank 50 for storing hydrogen to be supplied to the fuel cell 100, an air compressor 60 for supplying compressed air to the fuel cell 100, and the entire fuel cell system 10. The control part 80 to perform is included.

The fuel cell 100 includes an end plate 110, an insulating plate 120, a current collecting plate 130, and a single cell 140 each having a rectangular shape, and current collecting plates 130 on both sides of a plurality of stacked single cells, respectively. The insulating plate 120 and the end plate 110 are arranged in this order. Although various types of fuel cells can be used as the fuel cell 100, in this embodiment, a polymer electrolyte fuel cell is used as the fuel cell 100. The fuel cell 100 has a stack structure in which a plurality of single cells 140 are stacked. The single cell 140 is a unit module that generates power in the fuel cell 100, and generates power by an electrochemical reaction between hydrogen gas and oxygen contained in air. In this embodiment, the configuration and specifications of each single cell 140 are the same. A specific configuration of each cell will be described later with reference to FIG. In the present embodiment, the longitudinal direction of the rectangular unit cell 140 is also referred to as “x direction”, the short direction of the single cell 140 is also referred to as “y direction”, and the stacking direction of the single cells 140 is also referred to as “z direction”. The x direction, the y direction, and the z direction are orthogonal to each other.

Hydrogen as fuel gas stored in the hydrogen tank 50 is decompressed by the decompression valve 51 and then released to the hydrogen gas supply path 53, and adjusted to a predetermined pressure by the pressure regulating valve 52 provided in the hydrogen gas supply path 53. And supplied to the fuel cell 100. A gas containing hydrogen (anode supply gas) supplied to the fuel cell 100 is supplied to each single cell 140 via an anode gas supply manifold described later, and is used for power generation in each single cell 140. Gas (anode exhaust gas) containing hydrogen that has not been used in each single cell 140 is collected via an anode gas discharge manifold, which will be described later, and discharged to the outside of the fuel cell 100 via the anode exhaust gas passage 54. The fuel cell system 10 may be configured to recirculate the anode off-gas to the supply side by providing a connection path and a pump (not shown) that connect the hydrogen gas supply path 53 and the anode exhaust gas path 54.

The air compressor 60 pressurizes air as an oxidizing gas taken from the outside, and supplies it to the fuel cell 100 via the oxidizing gas supply path 61. Air containing oxygen (cathode supply gas) supplied to the fuel cell 100 is supplied to each single cell 140 via a cathode gas supply manifold described later, and is used for power generation in each single cell 140. Air (cathode exhaust gas) that has not been used in each single cell 140 is collected via a cathode gas discharge manifold, which will be described later, and discharged to the outside of the fuel cell 100 via a cathode exhaust gas path 63.

The refrigerant circulation pump 71 supplies the refrigerant to the fuel cell 100 via the refrigerant circulation passage 72. The refrigerant is guided to each single cell 140 via a refrigerant supply manifold described later, and cools each single cell 140. The refrigerant after cooling each single cell 140 is collected via a refrigerant discharge manifold, which will be described later, and circulated to the radiator 70 via the refrigerant circulation passage 73. The refrigerant cooled by the radiator 70 is supplied to the fuel cell 100 again. As the refrigerant, water or non-freezing water such as a mixed solution of water and ethylene glycol can be used. In this embodiment, liquid is used as the refrigerant, but air may be used as the refrigerant.

The control unit 80 is a computer having a CPU, memory, and the like (not shown). The control unit 80 receives signals from a temperature sensor, a pressure sensor, a voltmeter, and the like arranged in each unit of the fuel cell system 10 and controls the entire fuel cell system 10 based on the received signal.

A-2. Schematic configuration of fuel cell:
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of a single cell in the first embodiment. A unit cell 140 of the fuel cell 100 includes a power generator 200 including a membrane electrode assembly (also referred to as MEA) 210 in which electrodes of an anode 214 and a cathode 215 are formed on each surface of an electrolyte membrane 212, and a pair of separators (cathode side). The structure is sandwiched between the separator 300 and the anode-side separator 400). The power generation body 200 includes an anode side diffusion layer 226 disposed outside the anode 214 and a cathode side diffusion layer 227 disposed outside the cathode 215. The anode side diffusion layer 226 and the cathode side diffusion layer 227 are arranged so as to sandwich the MEA 210 from both sides, and supply hydrogen gas or air as a reaction gas to the anode 214 and the cathode 215 while diffusing each. The power generation body 200 has a porous material having gas diffusibility and conductivity, such as a metal porous body (for example, expanded metal) or a carbon porous body, outside at least one of the anode side diffusion layer 226 and the cathode side diffusion layer 227. You may provide the porous body flow path layer formed by these. The power generator 200 in the present embodiment corresponds to a “laminated body” in the claims.

The electrolyte membrane 212 is a solid polymer membrane formed of a fluorine resin material or a hydrocarbon resin material, and has good proton conductivity in a wet state. The cathode 215 and the anode 214 include, for example, carbon particles (catalyst support carrier) supporting a catalyst metal (for example, platinum) that progresses an electrochemical reaction, and a polymer electrolyte (for example, a fluorine-based resin) having proton conductivity. It is configured.

The cathode-side separator 300 and the anode-side separator 400 are formed of, for example, a carbon-made member such as dense carbon that has been made to be gas-impermeable by compressing carbon, or a gas-impermeable conductive member such as press-formed stainless steel. ing. The cathode side separator 300 and the anode side separator 400 have a concavo-convex shape for forming a gas flow path on the surface. The cathode separator 300 forms a cathode gas supply channel CSC through which cathode supply gas flows and a cathode gas discharge channel CEC through which cathode exhaust gas flows, between the cathode side diffusion layer 227 and the cathode side diffusion layer 227. The anode-side separator 400 forms an anode gas supply flow path ASC through which anode supply gas flows and an anode gas discharge flow path AEC through which anode exhaust gas flows through the anode-side diffusion layer 226. Further, the cathode side separator 300 and the anode side separator 400 are disposed so as to overlap each other between the two power generators 200 with the surfaces opposite to the surfaces in contact with the anode side diffusion layer 226 or the cathode side diffusion layer 227 being in contact with each other. Then, a refrigerant flow path LFC in which a refrigerant flows between the cathode side separator 300 and the anode side separator 400 is formed. The specific configuration of the separator will be described later with reference to FIGS.

The anode supply gas supplied from the hydrogen tank 50 (FIG. 1) flows into the anode gas supply passage ASC via the hydrogen gas supply passage 53 and an anode gas supply manifold described later. The anode supply gas flowing through the anode gas supply flow path ASC is supplied to the anode 214 while being diffused by the anode side diffusion layer 226, and is subjected to an electrochemical reaction. On the other hand, of the anode supply gas diffused in the anode side diffusion layer 226, the anode exhaust gas containing the anode supply gas that has not been subjected to the electrochemical reaction flows from the anode side diffusion layer 226 into the anode gas discharge channel AEC. The anode exhaust gas flowing through the anode gas discharge passage AEC is discharged to the outside of the fuel cell 100 via an anode gas discharge manifold and an anode exhaust passage 54 (FIG. 1) described later.

The cathode supply gas supplied from the air compressor 60 (FIG. 1) flows into the cathode gas supply channel CSC via the oxidizing gas supply channel 61 and a cathode gas supply manifold described later. The cathode supply gas flowing through the cathode gas supply channel CSC is supplied to the cathode 215 while being diffused by the cathode side diffusion layer 227, and is subjected to an electrochemical reaction. On the other hand, of the cathode supply gas diffused in the cathode side diffusion layer 227, the cathode exhaust gas containing the cathode supply gas that has not been subjected to the electrochemical reaction flows from the cathode side diffusion layer 227 into the cathode gas discharge channel CEC. The cathode exhaust gas flowing through the cathode gas discharge channel CEC is discharged to the outside of the fuel cell 100 via a cathode gas discharge manifold and a cathode exhaust gas channel 63 (FIG. 1) which will be described later.

The refrigerant Lc sent from the refrigerant circulation pump 71 flows into the refrigerant flow path LFC via the refrigerant circulation flow path 72 (FIG. 1) and a refrigerant supply manifold described later. The refrigerant Lc flowing through the refrigerant flow path LFC absorbs heat from the power generator 200 via the cathode side separator 300 or the anode side separator 400 and releases it to the refrigerant circulation flow path 73 (FIG. 1) via the refrigerant discharge manifold. Is done.

A-3. Schematic configuration of separator:
FIG. 3 is an explanatory diagram showing a schematic configuration of the cathode separator in the first embodiment. In this embodiment, since the cathode side separator 300 and the anode side separator 400 have the same shape, only the schematic configuration of the cathode side separator 300 will be described here. The cathode-side separator 300 has a rectangular plate-like outer shape, and openings for constituting a manifold are formed at both ends in the longitudinal direction (x direction). In addition to the cathode-side separator 300, the anode-side separator 400 and a frame-like member (not shown) formed on the outer periphery of the power generator 200 are similarly formed with openings, so that the single cell 140 includes the cathode-side separator 300. By stacking the frame-shaped member and the anode-side separator 400, these openings communicate with each other to form a plurality of manifolds.

Specifically, the single cell 140 includes an anode gas supply manifold 162 that distributes the anode supply gas supplied to the fuel cell 100 to each single cell 140, and a cathode supply gas supplied to the fuel cell 100 to each single cell. A cathode gas supply manifold 152 that distributes to 140, an anode gas discharge manifold 164 that collects anode exhaust gas discharged from each single cell 140 and discharges it to the outside of the fuel cell 100, and a cathode exhaust gas discharged from each single cell 140. The cathode gas discharge manifold 154 that collects and discharges the fuel cell 100 to the outside, the refrigerant supply manifold 172 that distributes the refrigerant Lc supplied to the fuel cell 100 to each single cell 140, and the refrigerant Lc discharged from each single cell 140 The refrigerant discharge manifold 1 that collects and discharges the fuel to the outside of the fuel cell 100 4, is formed. Each manifold is a flow path extending in a direction substantially parallel to the stacking direction (z direction) of the fuel cell 100.

The cathode-side separator 300 includes a gas supply channel groove 310, a gas discharge channel groove 320, and a gas movement channel groove 330 in addition to the above opening. The gas supply channel groove 310 forms a cathode gas supply channel CSC through which the cathode supply gas flows between the cathode side diffusion layer 227 and the gas supply channel groove 310. The gas supply channel groove 310 includes a gas supply bundle channel groove 311 and a plurality of gas supply branch channel grooves 312. The gas supply bundle channel groove 311 connects the cathode gas supply manifold 152 and the gas supply branch channel groove 312, and distributes the cathode supply gas flowing in from the cathode gas supply manifold 152 to each gas supply branch channel groove 312. The gas supply branch channel groove 312 has a long groove-like outer shape extending in the longitudinal direction (x direction) of the cathode-side separator 300, one end is connected to the gas supply bundle channel groove 311, and the other end is It is blocked by the blocking part Pb. The gas supply branch passage groove 312 in this embodiment corresponds to a “gas supply passage formation portion” in the claims.

On the other hand, the gas discharge channel groove 320 forms a cathode gas discharge channel CEC in which the cathode exhaust gas circulates with the cathode side diffusion layer 227. The gas discharge channel groove 320 includes a gas discharge bundle channel groove 321 and a plurality of gas discharge branch channel grooves 322. The gas discharge bundle channel groove 321 connects the cathode gas discharge manifold 154 and the gas discharge branch channel groove 322, collects the cathode exhaust gas flowing in from the gas discharge branch channel groove 322, and discharges it to the cathode gas discharge manifold 154. The gas discharge branch channel groove 322 has a long groove-like outer shape extending in the longitudinal direction (x direction) of the cathode-side separator 300, one end is closed by the closing portion Pb, and the other end is the gas discharge bundle flow. It is connected to the road groove 321. The gas discharge branch channel groove 322 in the present embodiment corresponds to a “gas discharge channel forming part” in the claims.

The cathode separator 300 does not have a configuration in which the gas supply channel groove 310 and the gas discharge channel groove 320 are integrated, but the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 are on the cathode side. There are provided so-called IDFF (Inter-Digitate-Flow-Field) -type channel grooves alternately arranged in the short direction (y-direction) of the separator 300. The cathode separator 300 is formed such that the flow direction of the cathode supply gas flowing through the gas supply bundle flow channel groove 311 and the flow direction of the cathode exhaust gas flowing through the gas discharge bundle flow channel groove 321 are both in the y direction. . Hereinafter, in the x direction of the cathode-side separator 300, the upstream side of the gas flowing in the gas supply bundle channel groove 311 and the gas discharge bundle channel groove 321 is also called the upstream side of the cathode-side separator 300, and the gas supply bundle flow The downstream side in the flow direction of the gas flowing through the channel groove 311 and the gas discharge bundle channel groove 321 is also referred to as the downstream side of the cathode separator 300. FIG. 2 shows a cross section of a region where the gas supply branch channel grooves 312 and the gas discharge branch channel grooves 322 are alternately arranged. Further, the number of the gas supply branch channel grooves 312 and the gas discharge branch channel grooves 322 can be arbitrarily set.

The cathode separator 300 is a rib that is an area formed on the top of a rib formed relatively convex by concave grooves on both sides between the gas supply branch channel groove 312 and the gas discharge branch channel groove 322. A plurality of areas Aw are provided. The cathode-side separator 300 includes a plurality of gas movement channel grooves 330 in each rib region Aw. The gas movement channel groove 330 has a narrow groove-shaped outer shape in which one end is connected to the gas supply branch channel groove 312 and the other end is connected to the gas discharge branch channel groove 322. As a result, a part of the cathode supply gas flowing through the cathode gas supply channel CSC does not pass through the cathode side diffusion layer 227 between the gas movement channel groove 330 and the cathode side diffusion layer 227, and the cathode gas is discharged. A bypass channel for moving to the channel CEC is formed. The gas supply branch channel groove 312, the gas discharge branch channel groove 322, and the gas movement channel groove 330 will be described in detail with reference to FIGS.

FIG. 4 is an explanatory view perspectively showing the gas supply branch channel groove and the gas discharge branch channel groove in the first embodiment. The lower side of FIG. 4 corresponds to the gas supply bundle channel groove 311 side of FIG. 3, and the upper side of FIG. 4 corresponds to the gas discharge bundle channel groove 321 side of FIG. As shown in FIG. 4, the gas supply branch channel groove 312 includes a pair of gas supply branch channel side surfaces 312 s and a gas supply branch channel blocking surface 312 b. Each of the pair of gas supply branch passage side surfaces 312 s has a long outer shape extending in a direction along the extending direction (x direction) of the gas supply branch passage groove 312, and the gas supply branch passage groove 312 extends in the y direction. Side surfaces on both sides are formed in the groove cross section. The gas supply branch channel closed surface portion 312b is formed on a surface in contact with the closed portion Pb of the gas supply branch channel groove 312. At the closed end portion of the gas supply branch channel groove 312, a pair of gas supply branch channel side surfaces 312s and Each is connected. In other words, the gas supply branch passage blocking surface portion 312b is formed so as to connect the ends of the pair of gas supply branch passage side portions 312s. The gas supply branch passage side surface 312s in this embodiment corresponds to a “side surface” in the claims. The gas supply branch passage blocking surface portion 312b in the present embodiment corresponds to a “closing surface portion” in the claims.

On the other hand, the gas discharge branch flow channel groove 322 includes a pair of gas discharge branch flow channel side surfaces 322s and a gas discharge branch flow channel blocking surface portion 322b. Each of the pair of gas discharge branch channel side surfaces 322s has an elongated outer shape extending in a direction along the extending direction (x direction) of the gas discharge branch channel groove 322, and the gas discharge branch channel groove 322 in the y direction. Side surfaces on both sides are formed in the groove cross section. The gas discharge branch channel closed surface portion 322b is formed on a surface in contact with the closed portion Pb of the gas discharge branch channel groove 322. At the closed end of the gas discharge branch channel groove 322, a pair of gas discharge branch channel side surfaces 322s and Each is connected. In other words, the gas discharge branch channel blocking surface portion 322b is formed to connect the ends of the pair of gas discharge branch channel side surfaces 322s.

In this embodiment, the groove width of the gas supply branch channel groove 312 and the gas discharge branch channel groove 322, that is, the width in the y direction is formed to be in the range of 0.8 mm to 2 mm. The depths of the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 are formed to be in the range of 0.2 mm to 1 mm. In the present embodiment, the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 are either a pair of gas supply branch channel side portions 312 s or a pair of gas discharge branch channel side portions 322 s (hereinafter each referred to simply as “pair”. The bottom surface portion is provided between the pair of side surface portions, and the side surface portions may be in direct contact with each other. That is, the cross-sectional shape of the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 is not limited to a shape having a side surface and a bottom surface as in a substantially U shape, but only a side surface as in a substantially V shape. The side surface may have a curved line as in a substantially U shape, or the boundary between the side surfaces is uniquely defined by the curved side surfaces on both sides. It may be a shape that cannot be defined.

The rib region Aw has a rectangular outer shape having a pair of long sides and a pair of short sides, one long side is in contact with the gas supply branch channel side surface 312s, and the other long side is a gas discharge branch channel side surface. It is in contact with the part 322s. In the rib region Aw, the position in the x direction of one short side is equal to the position in the x direction of the adjacent gas supply branch passage blocking surface portion 312b, and the position in the x direction of the other short side is the adjacent gas discharge. It is equal to the position in the x direction of the branch channel blocking surface portion 322b. The distance from one long side of the rib area Aw to the other long side, that is, the width in the y direction of the rib area Aw is formed to be in the range of 0.8 mm to 2 mm. In other words, the gap in the y direction between the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 is formed to be in the range of 0.8 mm to 2 mm.

The gas movement channel groove 330 linearly connects the gas supply branch channel side surface portion 312s in contact with one long side of the rib region Aw and the gas discharge branch channel side surface portion 322s in contact with the other long side. It is formed as follows. A plurality of gas movement flow path grooves 330 are arranged in parallel to each other in the rib region Aw. In the present embodiment, the gas movement flow path grooves 330 are arranged at equal intervals in the x direction in the entire range from one short side to the other short side of the rib region Aw. That is, in the x direction, the gas movement flow channel groove 330 is in the entire range from the gas supply branch flow passage blocking surface portion 312b adjacent to the rib region Aw to the gas discharge branch flow passage blocking surface portion 322b adjacent to the rib region Aw. They are arranged at equal intervals. Further, in the present embodiment, the gas movement flow channel groove 330 is located upstream of the position connected to the gas supply branch channel side surface 312s in the x direction from the position connected to the gas discharge branch channel side surface 322s. In such a manner, they are arranged obliquely with respect to the y direction.

FIG. 5 is an explanatory diagram for explaining the shape of the gas movement channel groove in the first embodiment. FIG. 5 schematically shows a configuration when the gas movement channel groove 330 is viewed from the gas supply branch channel groove 312. The gas movement channel groove 330 has a V-shaped cross section, is formed so that the groove depth is in the range of 30 μm to 150 μm, and the groove width, that is, the width in the x direction is in the range of 50 μm to 200 μm. It is formed to become. Further, the gas movement flow channel grooves 330 are arranged such that the arrangement interval (pitch) in the x direction is in the range of 0.3 mm to 1.2 mm. The gas movement flow channel groove 330 has a sectional area of the gas movement flow channel formed by the gas movement flow channel groove 330 and the cathode side diffusion layer 227, which is a cross sectional area of the cathode gas supply flow channel CSC or the cathode gas discharge flow channel CEC. It is formed so that it may become 1/10 or less. That is, the cross-sectional area of the gas moving flow channel groove 330 is formed to be 1/10 or less of the cross-sectional area of the gas supply branch channel groove 312 and the cross-sectional area of the gas discharge branch channel groove 322. Further, the gas movement flow channel groove 330 is formed so as to be more hydrophilic than the cathode side diffusion layer 227. Thereby, drainage by capillary pressure can be performed. The degree of hydrophilicity of the gas movement channel groove 330 may be such that the contact angle is less than 100 °, for example.

A-4. Example of effect:
Here, an example of an effect produced by using the cathode-side separator 300 in the fuel cell 100 will be described. FIG. 6 is an explanatory view schematically showing the vicinity of the boundary between the cathode side separator and the gas diffusion layer that are not provided with the gas movement flow channel as a comparative example. FIG. 7 is an explanatory view schematically showing the vicinity of the boundary between the cathode separator and the gas diffusion layer according to the first embodiment.

In the fuel cell 100w according to the comparative example, as shown in FIG. 6, when the liquid Wg is generated inside the cathode due to an electrochemical reaction or the like, the liquid Wg is inside the cathode side diffusion layer 227, particularly the rib region Aw of the cathode side separator 300w. It stays in the area that touches. This is because the inside of the cathode side diffusion layer 227 is extruded by the cathode supply gas supplied from the cathode gas supply channel CSC in the region in contact with the cathode gas supply channel CSC and the cathode gas discharge channel CEC. Further, the discharge to the cathode gas discharge channel CEC suppresses the retention of the liquid Wg, while the distance to the cathode gas supply channel CSC is long inside the region in contact with the rib region Aw. This is because the liquid Wg is not easily discharged due to an increase in gas pressure loss and a long distance to the cathode gas discharge channel CEC as a discharge destination. The liquid Wg stays in the cathode side diffusion layer 227 in the vicinity of the region in contact with the rib region Aw, so that the cathode supply is provided in the cathode side diffusion layer 227, particularly in the vicinity of the region in contact with the rib region Aw. Gas diffusion is hindered. Thereby, in the cathode 215, the area of the area | region where cathode supply gas is supplied reduces, and electric power generation efficiency falls.

On the other hand, since the fuel cell 100 according to the present embodiment includes the gas movement flow channel groove 330 between the gas supply branch channel groove 312 and the gas discharge branch channel groove 322, as shown in FIG. A gas movement channel is formed between the supply channel CSC and the cathode gas discharge channel CEC. The fuel cell 100 using a separator having an IDFF type channel groove such as the cathode side separator 300 has a pressure difference between the inside of the cathode gas supply channel CSC and the inside of the cathode gas discharge channel CEC during power generation. Therefore, the cathode supply gas inside the cathode gas supply channel CSC is led out to the cathode gas discharge channel CEC via the gas transfer channel by the gas transfer channel. That is, the cathode supply gas can be forced to flow between the rib region Aw of the cathode separator 300 w and the cathode diffusion layer 227. Thereby, even if the liquid Wg exists in the cathode side diffusion layer 227 in contact with the rib region Aw of the cathode side separator 300w, the liquid Wg in the cathode side diffusion layer 227 moves to the gas movement flow path side. Therefore, the liquid Wg can be prevented from staying in the cathode side diffusion layer 227. Therefore, the region where the diffusion of the cathode supply gas is hindered by the liquid Wg inside the cathode side diffusion layer 227 can be reduced, and the power generation efficiency can be improved.

A-5. Test example:
(First test)
In the first test, the difference in power generation performance depending on the presence / absence of a gas movement flow channel groove was examined using three cathode-side separators including the cathode-side separator according to one embodiment of the present invention. First, in the cathode-side separator 300 of Example 1 which is an aspect of the present invention, the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 have a groove width of 0.8 mm, and the rib region Aw has a width in the y direction. , 1.6 mm, and is provided with a gas movement channel groove 330 in the rib region Aw. The cathode side separator of Comparative Example 2 is different from the cathode side separator 300 of Example 1 only in that the gas movement flow channel groove 330 is not provided in the rib region Aw. The cathode side separator of Comparative Example 3 has the IDFF type channel groove as shown in FIG. 3 while the cathode side separator of Example 1 and Comparative Example 2 does not include the blocking portion Pb. The gas supply bundle channel groove 311 and the gas discharge bundle channel groove 321 have straight type channel grooves linearly connected by the gas supply branch channel groove 312 and the gas discharge branch channel groove 322. The cathode side separator of Comparative Example 3 does not include the gas movement flow path groove 330 in the rib region Aw. For three fuel cells using Example 1, Comparative Example 2, and Comparative Example 3, respectively, the power generation performance was compared under conditions of 40 ° C. and excessive humidification.

FIG. 8 is an explanatory diagram for explaining a test result in the first test. The vertical axis of the graph shown in FIG. 8 indicates the voltage (V) generated by power generation in the single cell of the fuel cell, and the horizontal axis indicates the current density (A / cm ² ) of the current flowing through the electrolyte membrane. In the fuel cell using the cathode-side separator that is not provided with the gas movement flow path of Comparative Example 2 and Comparative Example 3, in the high current density region (> 1A) where the electrochemical reaction is activated and the generation amount of the liquid Wg is increased. There is a voltage drop. From this, it can be seen that the diffusion of the cathode supply gas is hindered by the staying liquid Wg in the cathode side diffusion layer 227. In addition, since the voltage drop occurs in any of the fuel cells of Comparative Example 2 and Comparative Example 3, the voltage drop is not limited to the separator having a straight flow channel, but a separator having an IDFF flow channel. However, it can be seen that the liquid Wg staying in the cathode side diffusion layer 227 cannot be easily discharged when the gas movement flow path groove 330 is not provided.

(Second test)
In the second test, the case where the gas movement channel groove was formed in the separator having the IDFF type channel groove using three cathode side separators including the cathode side separator of Example 1 described above, and the straight type channel The difference in power generation performance when the gas transfer channel groove was formed in the separator having the groove was investigated. The cathode-side separator of Comparative Example 4 has a straight-type channel groove, and does not include the blocking portion Pb as compared with the cathode-side separator 300 shown in FIG. 3, and includes the gas supply branch channel groove 312 and the gas discharge branch channel. The groove 322 is formed so that the groove width is 0.8 mm, and the rib region Aw is 1.2 mm in width in the y direction. In addition, the cathode side separator of the comparative example 4 is not provided with the gas movement flow path groove 330 in the rib area | region Aw. The cathode separator of Comparative Example 5 is different from the cathode separator of Comparative Example 4 only in that the gas movement channel groove 330 is provided in the rib region Aw. The power generation performance of the three fuel cells using Example 1, Comparative Example 4, and Comparative Example 5 was compared at 40 ° C. under excessively humidified conditions.

FIG. 9 is an explanatory diagram for explaining a test result in the second test. The vertical axis and the horizontal axis of the graph shown in FIG. 9 are the same as those in FIG. 8, the vertical axis indicates the voltage (V) generated by power generation in the single cell of the fuel cell, and the horizontal axis indicates the current flowing through the electrolyte membrane. Current density (A / cm ² ). First, when Comparative Example 4 and Comparative Example 5 are compared, it can be seen that the power generation performance is improved by forming the gas movement flow channel groove even in the separator having the straight flow channel. However, compared with a separator having an IDFF type channel groove, the effect of improving the power generation performance by forming the gas movement channel groove is small. This is because a fuel cell using a separator having a straight channel groove is unlikely to generate a pressure difference between the cathode gas supply channel CSC and the cathode gas discharge channel CEC even during power generation. This is because the cathode supply gas does not flow through the gas movement flow path to such an extent that the liquid Wg staying in the side diffusion layer 227 can be sufficiently discharged. The effect of improving the power generation performance by forming the gas movement flow channel groove in the separator having the straight type flow channel groove is that the cathode supply gas is supplied to the cathode via the gas movement flow channel formed by the gas movement flow channel groove. This is caused by being supplied to a wider range of the side diffusion layer 227.

Further, when Example 1 and Comparative Example 5 are compared, the cathode side separator of Comparative Example 5 is 1.2 mm in the width in the y direction of the rib region Aw, whereas the cathode side separator 300 of Example 1 is. Since the width of the rib region Aw is 1.6 mm, the ratio of the gas supply branch channel grooves 312 in the short side direction (y direction) of the separator is relatively small. Therefore, the fuel cell 100 using the cathode-side separator 300 of Example 1 is inferior to the fuel cell using the cathode-side separator of Comparative Example 5 in supplying the cathode supply gas to the cathode 215. However, in the fuel cell 100 using the cathode separator 300 of Example 1, the cathode supply gas is forced to flow through the gas movement channel and the liquid Wg inside the cathode side diffusion layer 227 is discharged to the gas movement channel. Therefore, the cathode supply gas can be diffused in a wider range inside the cathode side diffusion layer 227 compared to the fuel cell using the cathode side separator of Comparative Example 5. Therefore, the fuel cell 100 using the cathode-side separator 300 of Example 1 can supply the cathode supply gas to a wider range of the cathode 215, and can greatly improve the power generation efficiency.

According to the cathode separator 300 according to the first embodiment described above, in the fuel cell using the separator having the IDFF type channel groove, between the cathode gas supply channel CSC and the cathode gas discharge channel CEC. Since the gas movement flow path for moving the cathode supply gas in the cathode gas supply flow path CSC to the cathode gas discharge flow path CEC can be formed, the liquid Wg stays in the cathode side diffusion layer 227. It is possible to suppress a decrease in power generation efficiency due to the above. Specifically, when the cathode-side separator 300 is used in the fuel cell 100, the ends thereof are connected to the cathode gas supply channel CSC and the cathode gas discharge channel CEC, respectively. A gas movement channel having a smaller cross-sectional area than the gas discharge channel CEC is formed between the cathode gas supply channel CSC and the cathode gas discharge channel CEC. Thereby, the fuel cell 100 forcibly circulates the cathode supply gas inside the gas movement channel during power generation and discharges the liquid Wg staying inside the cathode side diffusion layer 227 to the outside of the cathode side diffusion layer 227. Therefore, in a fuel cell using a separator having an IDFF type channel groove, reduction in power generation efficiency can be suppressed.

Conventionally, in a fuel cell using a separator having an IDFF type channel groove, the liquid Wg stays inside the cathode side diffusion layer 227 in contact with the rib region Aw of the separator, and the diffusion of the cathode supply gas is prevented. The power generation efficiency may be reduced. However, the fuel cell 100 using the cathode separator 300 according to the present invention uses the pressure difference between the cathode gas supply channel CSC and the cathode gas discharge channel CEC generated during power generation to use the cathode separator. The cathode supply gas can be forced to flow between the 300 w rib region Aw and the cathode side diffusion layer 227. Thereby, even if the liquid Wg exists inside the cathode side diffusion layer 227 in contact with the rib region Aw of the cathode side separator 300w, the liquid Wg moves to the gas movement channel side and is discharged from the gas movement channel. Therefore, the liquid Wg can be prevented from staying inside the cathode side diffusion layer 227. Therefore, the region where the diffusion of the cathode supply gas is hindered by the liquid Wg inside the cathode side diffusion layer 227 can be reduced, and the power generation efficiency can be improved.

According to the cathode-side separator 300 according to the first embodiment, the gas movement flow path grooves 330 are arranged at equal intervals in the x direction over the entire range from one short side to the other short side of the rib region Aw. Therefore, it is possible to suppress a decrease in power generation efficiency due to the liquid Wg staying inside the power generation body 200. Specifically, the liquid Wg generated by power generation or the like stays in a wide range inside the cathode side diffusion layer 227 and prevents diffusion of the cathode supply gas supplied from the cathode gas supply channel CSC. Therefore, by forming the gas movement channel groove 330 in the entire range of the rib region Aw, the cathode supply gas is forcibly forced between the rib region Aw of the cathode side separator 300w and the cathode side diffusion layer 227 in a wide range. The liquid Wg that flows and stays inside the cathode side diffusion layer 227 can be discharged to the outside of the cathode side diffusion layer 227. Therefore, power generation efficiency can be improved in a fuel cell using a separator having an IDFF type channel groove.

According to the cathode-side separator 300 according to the first embodiment, the gas movement flow channel groove 330 has a cross-sectional area of the gas movement flow channel that is 1 / of the cross-sectional area of the cathode gas supply flow channel CSC and the cathode gas discharge flow channel CEC. Since it is formed to be 10 or less, it is possible to suppress a decrease in power generation efficiency due to the liquid Wg staying inside the power generation body 200. Specifically, by setting the cross-sectional area of the gas movement flow path to 1/10 or less of the cross-sectional areas of the cathode gas supply flow path CSC and the cathode gas discharge flow path CEC to which both ends of the gas movement flow path are connected. A pressure difference is generated at both ends of the gas movement channel due to a pressure loss inside the gas movement channel. Due to this pressure difference, the gas can be forced to flow inside the gas movement channel, so that the liquid Wg staying inside the cathode side diffusion layer 227 can be discharged to the outside of the cathode side diffusion layer 227. . That is, power generation efficiency can be improved in a fuel cell using a separator having an IDFF type channel groove. As a specific example, the gas supply branch channel groove 312 and the gas discharge branch channel groove 322 are formed so that the groove width is in the range of 0.8 to 2 mm and the groove depth is in the range of 0.2 to 1 mm. A fuel cell using a separator having an IDFF type channel groove by forming the gas movement channel groove 330 to have a groove width of 50 to 200 μm and a groove depth of 30 to 150 μm. Therefore, the power generation efficiency can be improved.

A-6. Modification of the first embodiment:
FIG. 10 is an explanatory diagram for explaining a schematic configuration of a cathode-side separator in a modification of the first embodiment. FIG. 10 corresponds to FIG. 4 in the first embodiment. As shown in FIG. 4, in the first embodiment, a plurality of gas movement channel grooves 330 are arranged in parallel to each other in the rib region Aw, but the arrangement pattern of the gas movement channel grooves 330 is as follows. The present invention is not limited to the first embodiment, and other arrangement patterns may be provided. For example, like the cathode-side separator 300a shown in FIG. 10, the gas moving flow channel grooves 330a are formed so as to cross each other in the entire range from one short side to the other short side of the rib region Aw. May be. In this way, the liquid Wg that stays inside the cathode side diffusion layer 227 by forcibly flowing the cathode supply gas in a wider range between the rib region Aw of the cathode side separator 300a and the cathode side diffusion layer 227 can be obtained. It can be discharged to the outside of the cathode side diffusion layer 227.

FIG. 11 is an explanatory diagram for explaining the shape of the gas movement channel groove in the modification of the first embodiment. As shown in FIG. 5, in the first embodiment, the gas movement flow path groove 330 has a V-shaped cross section, but the cross-sectional shape of the gas movement flow path groove 330 is limited to the first embodiment. It may be a shape other than this. For example, as shown in FIG. 11A, the gas movement channel groove 330 has a plurality of corners in the cross section so that a polygonal gas movement channel other than a triangle is formed, such as a quadrangle or a pentagon. The shape provided may be sufficient, and as shown in FIG.11 (b), the shape which does not have a corner | angular part in a cross section may be sufficient so that a semicircle-shaped gas movement flow path may be formed.

B. Second embodiment:
In the first embodiment, the cathode side separator in which the gas movement channel grooves are arranged at equal intervals in the x direction has been described. In the second embodiment, the arrangement interval of the gas movement channel grooves is on the upstream side of the separator. Cathode side separators that are different on the downstream side will be described. Since the schematic configuration of the fuel cell system and the schematic configuration of the fuel cell other than the arrangement interval of the gas moving flow channel grooves formed in the cathode separator are the same as those in the first embodiment, description thereof will be omitted.

B-1. Schematic configuration of separator:
FIG. 12 is an explanatory diagram showing a schematic configuration of the cathode-side separator in the second embodiment. The cathode side separator 300b of the second embodiment has the same outer shape and opening as the cathode side separator of the first embodiment. Further, in the cathode side separator 300b of the second embodiment, the same reference numerals as those of the cathode side separator of the first embodiment are provided with the same shape and configuration as those of the first embodiment.

Similarly to the gas movement flow path groove 330 of the first embodiment, the gas movement flow path groove 330b of the second embodiment is mutually in the entire range from one short side to the other short side of the rib region Aw. A plurality are arranged in parallel. On the other hand, the gas movement flow path grooves 330b of the second embodiment are arranged so that the arrangement density on the upstream side of the separator is lower than the arrangement density on the downstream side in the rib region Aw. The arrangement density of the gas movement flow path grooves 330b refers to the ratio of the gas movement flow path grooves 330b included in the unit area of the rib area Aw. For example, the gas movement flow path grooves included in the unit area of the rib area Aw. The number can be specified by the number of 330b and the average value of the arrangement interval of the gas movement flow path grooves 330b in the unit area of the rib region Aw. In the present embodiment, the gas movement flow path grooves 330b are arranged such that the arrangement interval in the rib region Aw is wide on the upstream side of the separator and narrows toward the downstream side. Specifically, Wp1, Wp2, Wp3,..., Wpn-1, Wpn (n is an integer less than the number of the gas movement flow channel grooves 330b) by arranging the arrangement intervals of the gas movement flow channel grooves 330b in order from the upstream side. Then, the gas movement flow path grooves 330b are arranged such that the arrangement interval in the rib region Aw is Wp1 ≧ Wp2 ≧ Wp3 ≧... ≧ Wpn−1 ≧ Wpn.

B-2. Example of effect:
Here, an example of the effect produced by lowering the arrangement density of the gas moving flow channel grooves on the cathode side separator on the upstream side and increasing on the downstream side will be described. FIG. 13 is an explanatory view schematically showing the vicinity of the boundary between the cathode separator and the gas diffusion layer according to the second embodiment. In general, the fuel cell tends to be deficient in moisture due to the circulation of the cathode supply gas or the like on the upstream side of the cathode 215 or the cathode diffusion layer 227 in the flow direction of the cathode supply gas. On the other hand, in the fuel cell using the cathode separator 300b, the arrangement density of the gas moving flow path is low on the upstream side in the flow direction of the cathode supply gas, and therefore, the cathode side diffusion layer 227 from the gas moving flow path to each region of the cathode 215. The diffusion distance of the cathode supply gas inside is long, and the diffusion resistance of the gas can be increased on the upstream side of the cathode 215 and the cathode side diffusion layer 227. Thereby, the fuel cell using the cathode side separator 300b can suppress moisture discharge on the upstream side of the cathode 215 or the cathode side diffusion layer 227 to improve the moisture retention.

On the other hand, in general, in a fuel cell, moisture tends to stay on the downstream side of the cathode 215 and the cathode-side diffusion layer 227 in the flow direction of the cathode supply gas, and the moisture tends to be excessive. On the other hand, in the fuel cell using the cathode-side separator 300b, the arrangement density of the gas movement channels is high on the downstream side in the flow direction of the cathode supply gas, and therefore, the cathode-side diffusion layer 227 from the gas movement channel to each region of the cathode 215. The diffusion distance of the cathode supply gas inside can be shortened. As a result, the fuel cell using the cathode separator 300b increases the supply amount of the cathode supply gas to the cathode 215 so that the cathode supply gas supplied to the downstream side of the cathode 215 or the cathode diffusion layer 227 is insufficient. Occurrence can be suppressed.

B-3. Test example:
(Third test)
In the third test, using three cathode-side separators, the difference in power generation performance by changing the arrangement interval of the gas movement flow channel grooves between the upstream side and the downstream side of the separator was examined. First, as shown in FIG. 12, in the cathode side separator 300b of Example 2 which is an aspect of the present invention, the arrangement density of the gas moving flow channel grooves 330b is low on the upstream side of the separator and is downstream in the rib region Aw. It is arranged to be higher on the side.

FIG. 14 is an explanatory diagram showing a schematic configuration of the cathode-side separator in Comparative Example 6. The cathode-side separator 300x of Comparative Example 6 has the same configuration as that of the cathode-side separator 300b of Example 2 except for the arrangement density of the gas moving flow channel grooves in the rib region Aw. The cathode-side separator 300x is formed so that the arrangement density of the gas movement flow path grooves 330x in the rib region Aw is equal on the upstream side and the downstream side of the separator. Specifically, as shown in FIG. 14, the cathode-side separator 300x is formed such that in the rib region Aw, the arrangement intervals of the gas movement flow path grooves 330b in the x direction are all constant at Wpx.

FIG. 15 is an explanatory diagram showing a schematic configuration of the cathode-side separator in Comparative Example 7. FIG. 16 is an explanatory view illustrating a part of the YY cross section of FIG. The cathode-side separator 300y of Comparative Example 7 is provided with a straight type gas channel groove Ggf, the width of the gas channel groove Ggf is narrowed on the upstream side in order to suppress moisture deficiency, and the cathode supply gas is downstream. In order to increase the supply amount of the gas, the gas channel groove Ggf is formed to have a wide width. The cathode separator 300y does not include a gas movement flow path groove in the rib region Aw. In addition, in the separator having the straight type gas flow channel groove, the following problems are pointed out with respect to the configuration in which the width of the gas flow channel groove is changed between the upstream side and the downstream side as in Comparative Example 7. ing. As shown in FIG. 16, in the cathode-side separator 300y, on the upstream side, the gas passage groove Ggf has a narrow width, so that the supply capacity of the cathode supply gas decreases. On the other hand, on the downstream side, since the width of the rib region Aw is narrow, the cooling capacity by the refrigerant Lc via the cathode-side separator 300y decreases. That is, the improvement in cathode supply gas supply capacity and the improvement in cooling capacity by the refrigerant Lc are contradictory.

Above, Example 2, Comparative Example 6, and were maintained Comparative Example 7 for three fuel cells using respectively, the current density of the current flowing through the electrolyte membrane (A / cm ²⁾ to 1.2A / cm ² The power generation performance was compared in the state. FIG. 17 is an explanatory diagram for explaining a test result in the third test. The vertical axis of the graph shown in FIG. 17 indicates the cell voltage (V), and the horizontal axis indicates the cell temperature (° C.). Comparing Example 2 and Comparative Example 6 with Comparative Example 7, it can be seen that the power generation performance in the low temperature region is improved when the gas movement channel groove is formed in the separator. This is because the moisture inside the cathode 215 and the cathode-side diffusion layer 227 can be easily discharged to the outside by the gas movement channel groove. It can also be seen that when the gas movement channel groove is formed in the separator, the power generation performance is improved even in a high temperature region. This is because the contact area between the rib region Aw and the cathode-side diffusion layer 227 can be sufficiently secured even on the downstream side by the gas movement flow channel groove, and therefore, it can be easily cooled by the refrigerant Lc.

Further, comparing Experimental Example 2 with Comparative Example 6, the cathode-side separator 300b of Example 2 has a low arrangement density of the gas moving flow channel grooves on the upstream side, and therefore, dry-up on the upstream side is suppressed by the moisturizing effect. It can be seen that the power generation performance is improved. In addition, since the cathode side separator 300b of Example 2 has a high arrangement density of the gas moving flow channel grooves on the downstream side, the supply amount of the cathode supply gas to the cathode 215 increases on the downstream side where moisture tends to stay, and the power generation performance. It can be seen that is improved.

According to the cathode side separator 300b according to the second embodiment described above, the separator having the gas moving flow channel groove is used by changing the arrangement density of the gas moving flow channel grooves 330b between the upstream side and the downstream side. The power generation efficiency of the conventional fuel cell can be further improved. Specifically, since the cathode side separator 300b has a low arrangement density of the gas moving flow channel grooves on the upstream side, it is possible to suppress the occurrence of dry-up due to the moisturizing effect. Further, since the cathode-side separator 300b has a high arrangement density of gas movement flow channel grooves on the downstream side, the supply amount of the cathode supply gas supplied to the cathode 215 can be increased. By these, the power generation efficiency of the fuel cell can be further improved.

In general, the cathode 215 and the cathode side diffusion layer 227 of the fuel cell are likely to be deficient in moisture due to deprivation of moisture by the cathode supply gas on the upstream side in the flow direction of the cathode supply gas. On the other hand, on the downstream side in the flow direction of the cathode supply gas, moisture tends to stay and the moisture tends to be excessive. However, since the cathode side separator 300b of the present embodiment has a low arrangement density of the gas movement flow channel grooves on the upstream side, the fuel cell using the cathode side separator 300b has a gas movement on the upstream side as shown in FIG. The diffusion distance of the cathode supply gas from the flow path to each region of the cathode 215 becomes longer, and moisture discharge due to the cathode supply gas can be suppressed. On the other hand, since the cathode side separator 300b of this embodiment has a high arrangement density of the gas movement flow path grooves on the downstream side, the fuel cell using the cathode side separator 300b has a gas movement on the downstream side as shown in FIG. The diffusion distance of the cathode supply gas from the flow path to each region of the cathode 215 is shortened, and the supply amount of the cathode supply gas to the cathode 215 can be increased. Accordingly, it is possible to suppress a decrease in power generation efficiency due to insufficient supply of the cathode supply gas to the cathode 215 even in a state where moisture remains.

C. Third embodiment:
In the first embodiment, the cathode side separator having the gas movement flow channel groove that linearly connects the gas supply branch channel groove and the gas discharge branch channel groove has been described. In the third example, the gas supply branch channel is described. A cathode-side separator having a gas supply branch channel groove in which a part of the groove is divided between the groove and the gas discharge branch channel groove will be described. Since the schematic configuration of the fuel cell system and the schematic configuration of the fuel cell are the same as those in the first embodiment except for the shape of the gas transfer channel groove formed in the cathode-side separator, description thereof will be omitted. However, the fuel cell according to the third embodiment is installed such that the direction along the y direction in FIGS. 1 and 2 is the gravity direction (vertical direction).

C-1. Schematic configuration of separator:
FIG. 18 is an explanatory diagram showing a schematic configuration of the cathode-side separator in the third embodiment. The cathode side separator 300c of the third embodiment has the same outer shape and opening as the cathode side separator of the first embodiment. Further, in the cathode side separator 300c of the third embodiment, the same reference numerals as those of the cathode side separator of the first embodiment are provided with the same shape and configuration as in the first embodiment. As shown in FIG. 18, the cathode-side separator 300c of the third embodiment is arranged in the fuel cell so that the gas supply branch channel grooves 312 and the gas discharge branch channel grooves 322 are alternately arranged along the direction of gravity. Specifically, the cathode-side separator 300c of the third embodiment includes a gas supply branch channel groove 312 and a gas discharge branch channel groove 322 that correspond to each other. The gas discharge branch channel groove 322 is arranged in the direction of the lower side in the direction of gravity.

Similarly to the gas movement flow path groove 330 of the first embodiment, the gas movement flow path groove 330c of the third embodiment is mutually in the entire range from one short side to the other short side of the rib region Aw. A plurality are arranged in parallel. On the other hand, the gas movement channel groove 330c of the third embodiment is formed in a part of the rib regions Aw among the plurality of rib regions Aw formed between the gas supply branch channel groove 312 and the gas discharge branch channel groove 322. A part of the groove is closed by the closing part Pp. Specifically, the gas movement flow path groove 330c of the third embodiment is the first closed type gas movement flow path groove 330c1 or the second closed type gas movement flow path in which a part of the groove is closed by the closed portion Pp. It includes a groove 330c2 and a communication type gas movement flow path groove 330c3 that is communicated from the upper end to the lower end without being closed by the closing portion Pp.

The cathode-side separator 300c includes a first rib region Aw1 in which the upper long side is in contact with the gas discharge branch channel groove 322 and the lower long side is in contact with the gas supply branch channel groove 312 in the rib region Aw. The first closed type gas moving flow channel groove 330c1 or the second closed type gas moving flow channel groove 330c2 is formed. On the other hand, the cathode-side separator 300c has a second rib region Aw2 in which the upper long side is in contact with the gas supply branch channel groove 312 and the lower long side is in contact with the gas discharge branch channel groove 322 in the rib region Aw. Is formed with a communication type gas movement flow path groove 330c3.

The first closed type gas moving flow channel groove 330c1 has the same outer shape as the gas moving flow channel groove 330 of the first embodiment, but the upper end portion of the groove in contact with the gas discharge branch flow channel groove 322 is a closed portion. It is blocked by Pp. The second closed type gas movement flow path groove 330c2 has the same outer shape as the gas movement flow path groove 330 of the first embodiment, but the central part of the groove is closed by the closing part Pp. On the other hand, the communication type gas movement flow path groove 330c3 is connected to the gas discharge branch flow path groove 322 from one end connected to the gas supply branch flow path groove 312 similarly to the gas movement flow path groove 330 of the first embodiment. The groove communicates with the other connected end.

C-2. Example of effect:
Here, a part of the gas movement channel groove formed in the first rib region Aw1 in which the gas discharge branch channel groove 322 is on the upper side and the gas supply branch channel groove 312 is on the lower side is blocked by the blocking portion Pp. An example of the effect produced by the above will be described with reference to FIGS. FIG. 19 is an explanatory view schematically showing the vicinity of the boundary between the first closed gas movement channel groove formed in the cathode side separator and the gas diffusion layer. FIG. 20 is an explanatory view schematically showing the vicinity of the boundary between the second closed-type gas movement channel groove formed in the cathode-side separator and the gas diffusion layer. FIG. 21 is an explanatory diagram for explaining the movement direction of moisture in the cathode-side separator in the comparative example. FIG. 22 is an explanatory diagram for explaining the movement direction of moisture in the cathode-side separator in this example.

As shown in FIGS. 19 and 20, the cathode-side separator 300c has the first closed gas movement flow channel groove 330c1 or the second closed gas movement flow channel groove 330c2 formed in the first rib region Aw1, In the fuel cell using the cathode separator 300c, the gas movement channel formed between the upper cathode gas discharge channel CEC and the lower cathode gas supply channel CSC is closed by the blocking part Pp. Thereby, it is possible to suppress the liquid Wg discharged to the cathode gas discharge channel CEC from moving to the lower cathode gas supply channel CSC due to gravity inside the fuel cell. On the other hand, since the cathode-side separator 300c has the communication gas movement channel groove 330c3 formed in the second rib region Aw2, the cathode-side separator 300c is discharged into the cathode gas supply channel CSC inside the fuel cell using the cathode-side separator 300c. The liquid Wg thus discharged can be discharged to the lower cathode gas discharge channel CEC by gravity.

As shown in FIG. 21, the fuel cell using the cathode-side separator 300z in which all the gas movement flow path grooves formed in the rib region Aw are in communication type has all the cathode gas supply flow paths CSC by the gas movement flow path. And the cathode gas discharge channel CEC communicate with each other. Therefore, when the fuel cell is used in a state where the cathode gas supply channel CSC and the cathode gas discharge channel CEC are aligned in the direction of gravity, the liquid Wg moves downward due to gravity, and the liquid is formed in the channel formed below. Wg stays. Thereby, since the circulation of the cathode supply gas is suppressed by the retained liquid Wg, there is a problem that the power generation performance is deteriorated. However, as shown in FIG. 22, the fuel cell using the cathode-side separator 300c of this embodiment suppresses the liquid Wg from moving from the cathode gas discharge channel CEC to the lower cathode gas supply channel CSC due to gravity. The liquid Wg can be collected in the cathode gas discharge channel CEC and discharged to the cathode gas discharge manifold 154 together with the cathode exhaust gas. Thereby, the fall of the power generation performance by retention of the liquid Wg can be suppressed.

The cathode side separator 300c of the present embodiment does not have a configuration in which the first rib region Aw1 is not provided with the gas movement flow channel groove, but the first closed type gas movement in which a part of the groove is closed by the closed portion Pp. The flow path groove 330c1 or the second closed type gas movement flow path groove 330c2 is provided. The effect obtained by this will be further described. As shown in FIGS. 19 and 20, the fuel cell using the cathode side separator 300c is connected to the cathode side separator 300c and the cathode by the first closed type gas moving flow channel groove 330c1 or the second closed type gas moving flow channel groove 330c2. Between the side diffusion layer 227, a gas movement flow path blocked by the blocking portion Pp is formed. As a result, the cathode supply gas supplied from the cathode gas supply channel CSC is supplied to a wider range of the cathode side diffusion layer 227 via the closed gas movement channel, thereby improving the power generation efficiency. Can be planned. In the first closed type gas moving flow channel groove 330c1 and the second closed type gas moving flow channel groove 330c2, the first closed type gas moving flow channel groove 330c1 is connected to the cathode gas supply flow channel CSC. Since the length of the flow path becomes long, the power generation efficiency can be further increased.

C-3. Test example:
(4th test)
In the fourth test, the difference in power generation performance was examined by using two cathode-side separators to block part of the gas movement flow channel groove formed in the first rib region Aw1 with the blocking portion Pp. First, as a cathode-side separator of Example 3 which is an aspect of the present invention, the first closed gas movement flow channel groove 330c1 or the second closed gas movement flow channel groove in the first rib region Aw1 shown in FIG. The cathode side separator 300c in which 330c2 was formed was used. On the other hand, as Comparative Example 8, a cathode-side separator 300z shown in FIG. 21 in which all the gas movement flow channel grooves formed in the rib region Aw are of the communication type was used.

The two fuel cell using Example 3 and Comparative Example 8, respectively, were subjected to comparison of power generation performance in a state in which the current density of the current flowing through the electrolyte membrane (A / cm ²⁾ was maintained at 1.2A / cm ² . FIG. 23 is an explanatory diagram for explaining a test result in the fourth test. The vertical axis of the graph shown in FIG. 23 indicates the cell voltage (V), and the horizontal axis indicates the cell temperature (° C.). When Example 3 and Comparative Example 8 are compared, it can be seen that, in the separator, the power generation performance in the low temperature region is improved when the gas movement flow path groove formed in the first rib region Aw1 is closed by the closing portion Pp. This is because, as described above, the liquid Wg discharged to the cathode gas discharge channel CEC is discharged from the cathode gas discharge manifold 154 without moving to the lower cathode gas supply channel CSC, thereby improving the power generation performance. It is.

According to the cathode side separator 300c according to the third embodiment described above, the gas discharge branch channel groove 322 is formed in the first rib region Aw1 in the gravity direction upper side and the gas supply branch channel groove 312 is in the gravity direction lower side. Since a part of the gas movement channel groove to be formed is blocked by the blocking part Pp, the power generation efficiency of the fuel cell using the separator having the gas movement channel can be further improved. Specifically, in the fuel cell using the cathode separator 300c, the gas movement channel formed between the upper cathode gas discharge channel CEC and the lower cathode gas supply channel CSC has a closed portion Pp. Therefore, the liquid Wg discharged to the cathode gas discharge channel CEC can be prevented from moving to the lower cathode gas supply channel CSC due to gravity. Thereby, it is possible to reduce the occurrence of a state in which the liquid Wg stays in the flow path formed on the lower side in the gravity direction and the flow of the cathode supply gas is suppressed. That is, it is possible to suppress a decrease in power generation performance due to non-uniform distribution of the cathode supply gas in the cathode gas supply channel CSC.

In the fuel cell using the separator having the gas moving flow path, the cathode supply gas can be forced to flow between the rib region Aw and the cathode side diffusion layer 227 to improve the power generation efficiency. When the channel grooves 312 and the gas discharge branch channel grooves 322 are alternately arranged in the gravity direction, the liquid Wg inside moves to a channel formed on the lower side in the gravity direction of the separator and moves below the separator. On the side, there is a possibility that the flow of the cathode supply gas may be hindered. However, as shown in the present embodiment, the gas movement channel is formed in the rib region Aw of the separator by closing the gas movement channel groove formed in the first rib region Aw1 with the closing part Pp. While obtaining, the malfunction which arises by forming a gas movement flow path in rib area | region Aw can be aimed at.

In addition, the cathode-side separator 300c shown in the present embodiment does not have a configuration in which the first rib region Aw1 is not provided with a gas movement flow channel groove, but a closed type in which a part of the groove is closed by a closed portion Pp. Therefore, the power generation efficiency of the fuel cell can be further improved. Specifically, in the fuel cell using the cathode-side separator 300c, a gas movement flow path closed by the closing portion Pp is formed between the cathode-side separator 300c and the cathode-side diffusion layer 227. As a result, the cathode supply gas supplied from the cathode gas supply channel CSC is supplied to a wider area of the cathode side diffusion layer 227 via the closed gas movement channel, thereby improving the power generation efficiency. be able to.

C-4. Modification of the third embodiment:
FIG. 24 is an explanatory diagram for explaining a schematic configuration of a cathode-side separator in Modification 1 of the third embodiment. In the third embodiment, as shown in FIG. 18, the cathode-side separator 300c includes two types of first closed gas movement flow channel grooves 330c1 and second closed gas movement flow channel grooves 330c2 in the first rib region Aw1. Although the gas movement channel groove is formed, the gas movement channel groove formed in the first rib region Aw1 does not have to be two types, and may be one type or three or more types. May be. For example, as shown in FIG. 24, in the cathode-side separator 300d, only the first closed-type gas movement flow path groove 330c1 may be formed in the first rib region Aw1, or the second closed-type gas movement flow path groove may be formed. Only 330c2 may be formed. Further, the cathode-side separator may be formed with three or more types of closed gas movement flow channel grooves in the first rib region Aw1 having different positions and ranges closed by the closed portion Pp. In any of these cases, the same effect as that shown in the above embodiment can be obtained, so that the power generation efficiency of the fuel cell using the separator having the gas moving flow path can be further improved. .

FIG. 25 is an explanatory diagram for explaining a schematic configuration of the cathode-side separator in the second modification of the third embodiment. In the third embodiment, as shown in FIG. 18, the cathode-side separator 300c has a gas movement flow channel groove, either the first closed gas movement flow channel groove 330c1 or the second closed gas movement flow channel groove 330c2. Although it is formed in the first rib region Aw1, it may be configured such that no gas movement channel groove is formed in the first rib region Aw1, as in the cathode-side separator 300e shown in FIG. Even in this case, the liquid Wg discharged to the cathode gas discharge channel CEC is prevented from moving to the lower cathode gas supply channel CSC due to gravity inside the fuel cell using the cathode separator 300e. Therefore, it is possible to suppress problems caused by forming the gas movement channel in the first rib region Aw1, while obtaining the advantage of forming the gas movement channel in the second rib region Aw2 of the separator.

FIG. 26 is an explanatory diagram for explaining a schematic configuration of the cathode separator in the third modification of the third embodiment. In the cathode-side separator 300e of Modification 2 shown in FIG. 25, the relationship between the width W1 of the first rib region Aw1 in the gravity direction (y direction) and the width W2 of the second rib region Aw2 in the y direction is particularly limited. However, as shown in FIG. 26, by using the width W1 of the first rib area Aw1 to be not more than 0.8 times the width W2 of the second rib area Aw2, the fuel using the separator having the gas movement flow path is used. The power generation efficiency of the battery can be further improved. Specifically, the contact area between the first rib region Aw1 and the cathode side diffusion layer 227 can be reduced by reducing the width W1 of the first rib region Aw1. Thereby, since the retention of the liquid Wg in the cathode side diffusion layer 227 in contact with the first rib region Aw1 can be suppressed, the power generation efficiency can be further improved.

D. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

D1. Modification 1:
In the present embodiment, a plurality of gas movement channel grooves 330 are arranged so as to be parallel to each other in the rib region Aw, but each gas movement channel groove 330 is connected to the cathode gas supply channel CSC. As long as a gas movement flow path communicating with the cathode gas discharge flow path CEC can be formed, it is not always necessary to be parallel to each other. In the present embodiment, a plurality of gas movement channel grooves 330 are arranged side by side in the entire range from one short side to the other short side of the rib region Aw. Plural 330 may be located in a part of the rib area Aw, or only one 330 may be arranged in a part of the rib area Aw. Further, in this embodiment, the gas movement flow path grooves 330 are shown to have the same number and interval in each rib area Aw, but the number of gas movement flow path grooves 330 for each rib area Aw The interval may be different. Further, in the present embodiment, the gas movement flow path grooves 330 and 430 are formed in a straight line, but at least a part thereof may be a curve or a part thereof may be bent.

D2. Modification 2:
In the present embodiment, the fuel cell 100 is described as a configuration in which the diffusion layer and the separator are in contact with each other. However, the fuel cell 100 has a gas flow path member such as foam metal or punching metal between the diffusion layer and the separator. The separator may be in contact with the gas flow path member. Even in this case, it is possible to suppress a decrease in power generation efficiency due to the liquid Wg remaining in the gas flow path member and the diffusion layer in addition to the gas flow path.

D3. Modification 3:
In this embodiment, the cathode-side separator 300 and the anode-side separator 400 are used in a fuel cell in a state where the cathode-side separator 300 and the anode-side separator 400 are stacked. It can also be realized as a separator.

D4. Modification 4:
In the present embodiment, the fuel cell 100 is a solid polymer fuel cell, but the present invention can also be applied to other types of fuel cells (for example, direct methanol fuel cells and phosphoric acid fuel cells). is there.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 50 ... Hydrogen tank 60 ... Air compressor 70 ... Radiator 80 ... Control part 100 ... Fuel cell 110 ... End plate 120 ... Insulating plate 130 ... Current collecting plate 140 ... Single cell 152 ... Cathode gas supply manifold 154 ... Cathode Gas discharge manifold 162 ... Anode gas supply manifold 164 ... Anode gas discharge manifold 172 ... Refrigerant supply manifold 174 ... Refrigerant discharge manifold 200 ... Power generator 210 ... MEA
DESCRIPTION OF SYMBOLS 212 ... Electrolyte membrane 214 ... Anode 215 ... Cathode 226 ... Anode side diffusion layer 227 ... Cathode side diffusion layer 300 ... Cathode side separator 310 ... Gas supply channel groove 311 ... Gas supply bundle channel groove 312 ... Gas supply branch channel groove 312b ... gas supply branch channel closed surface portion 312s ... gas supply branch channel side surface portion 320 ... gas discharge channel groove 321 ... gas discharge bundle channel groove 322 ... gas discharge branch channel groove 322b ... gas discharge branch channel closed surface portion 322s ... gas discharge branch Road side surface portion 330... Gas movement passage groove 400... Anode side separator 410. Gas supply passage groove 411. Gas supply bundle passage groove 412. Gas supply branch passage groove 420. Channel groove 422 ... Gas discharge branch channel groove Pb, Pp ... Blocking portion Lc ... Refrigerant Aw ... Rib area CEC ... Cathode gas discharge passage AEC ... anode gas discharge channel LFC ... coolant channel CSC ... cathode gas supply passage ASC ... anode gas supply conduit

Claims

A separator for a fuel cell disposed in contact with a laminate including a membrane electrode assembly,
A gas supply channel for supplying gas to the membrane electrode assembly, the gas supply channel for forming a gas supply channel having a closed end on the downstream side in the gas flow direction between the laminated body A gas supply flow path forming section;
A gas discharge flow path for discharging gas from the membrane electrode assembly, for forming a gas discharge flow path between the laminated body and a closed end on the upstream side in the gas flow direction. A gas discharge flow path forming section;
One end is connected to the gas supply flow path, the other end is connected to the gas discharge flow path, and a gas movement flow path for moving the gas in the gas supply flow path to the gas discharge path A separator comprising: a gas movement flow path forming portion for forming a gas movement flow path having a smaller cross-sectional area than the gas supply flow path and the gas discharge flow path between the laminated body.
The separator according to claim 1,
Each of the gas supply flow path forming portion and the gas discharge flow path forming portion has a groove shape extending along a first direction, and both the gas flow directions are in the first direction. , Arranged alternately along the second direction,
The separator further includes
A region formed at the top of the rib formed by the gas supply channel forming part and the gas discharge channel forming part, the rib region extending along the first direction,
The gas movement flow path forming part has a groove shape formed in a straight line, and is formed in the rib region.
The separator according to claim 2,
The gas supply flow path forming section and the gas discharge flow path forming section are each a pair of side surface portions extending along a first direction, and a closed surface portion connecting the end portions of the pair of side surface portions, With
The rib regions are respectively formed between the side surface portion of the gas supply channel forming portion and the side surface portion of the gas discharge channel forming portion,
The gas movement flow path forming portion has one end portion in which the position in the first direction is equal to the closing surface portion of the gas supply path forming portion in at least some of the rib regions. To the closed surface portion of the gas discharge path forming portion and the other end portion having the same position in the first direction, and is formed at predetermined intervals along the first direction. , Separator.
The separator according to claim 3,
The predetermined interval is an interval in the range of 0.3 to 1.2 mm,
The separator, wherein the gas supply flow path forming part and the gas discharge flow path forming part are alternately arranged so that the distance between them in the second direction is in the range of 0.8 to 2 mm.
The separator according to any one of claims 1 to 4,
The gas movement flow path forming unit is a separator formed such that a cross-sectional area of the gas movement flow path is 1/10 or less of a cross-sectional area of the gas supply path and the gas discharge flow path.
In the separator according to any one of claims 2 to 5,
The gas supply flow path forming portion and the gas discharge flow path forming portion have a groove width in the range of 0.8 to 2 mm and a groove depth in the range of 0.2 to 1 mm, respectively. Formed,
The gas transfer flow path forming portion is a separator formed such that the groove width is in the range of 50 to 200 μm and the groove depth is in the range of 30 to 150 μm.
The separator according to any one of claims 3 to 6,
The arrangement density of the gas movement flow path forming part in the rib area is higher than the area in contact with the upstream side of the gas supply flow path forming part and the gas discharge flow path forming part. The separator is higher in the area in contact with the downstream side of the discharge flow path forming portion.
The separator according to any one of claims 3 to 7,
The second direction is a vertical direction;
The gas movement flow path forming portion has an upper end side in contact with the side surface portion of the gas supply flow path forming portion and a lower end side in contact with the side surface portion of the gas discharge flow path forming portion among the plurality of rib regions. A separator formed only in the rib region.
The separator according to any one of claims 3 to 7,
The second direction is a vertical direction;
The gas movement flow path forming part has an upper end side in contact with the side surface part of the gas discharge flow path forming part and a lower end side in contact with the side surface part of the gas supply flow path forming part among the plurality of rib regions. A separator comprising a closing portion for closing a part of the gas movement channel in the rib region.
In the separator according to claim 8 or 9,
The width in the vertical direction of the rib region where the upper end side is in contact with the side surface portion of the gas supply flow path forming portion and the lower end side is in contact with the side surface portion of the gas discharge flow path forming portion is as follows. The separator is wider than the width in the vertical direction of the rib region that is in contact with the side surface portion and the lower end side is in contact with the side surface portion of the gas supply flow path forming portion.
The separator according to any one of claims 3 to 10,
In the rib region, the gas movement flow path forming unit is configured to have the closed surface portion of the gas discharge path forming portion from one end portion of the gas supply path forming portion having the same position in the first direction as the closed surface portion. And a separator that is formed so as to be parallel to each other or cross each other in the entire range between the same position in the first direction and the other end.
The separator according to any one of claims 2 to 11,
The gas movement flow path forming unit is a separator having a shape in which a cross-sectional shape of the gas movement flow path is any one of a triangular shape, a quadrangular shape, and a semicircular shape.
The separator according to any one of claims 2 to 12,
The gas movement flow path forming part is a separator having a higher hydrophilicity than a contact surface in contact with the separator of the laminate.
The separator according to any one of claims 2 to 12,
In order to cool the fuel cell on the second surface opposite to the first surface on which the gas supply flow path forming section, the gas flow path forming section, and the gas movement flow path forming section are respectively formed. A separator having a liquid flow path forming part for forming a liquid flow path for circulating the liquid.
A fuel cell,
A laminate including a membrane electrode assembly;
A fuel cell comprising: the separator according to claim 1 disposed on both sides of the laminate.
A fuel cell,
A laminate including a membrane electrode assembly;
A plurality of separators according to claim 14 disposed on both sides of the laminate,
Each of the separators is a fuel cell in which the liquid flow path forming portion is arranged so as to face the liquid flow path forming portion of another separator.
The fuel cell according to claim 15 or 16, wherein
The laminate includes a gas diffusion layer disposed in contact with the membrane electrode assembly,
The fuel cell, wherein the separator is in contact with the gas diffusion layer.