JP7187346B2 - Fuel cell and fuel cell stack - Google Patents

Description

The present invention relates to fuel cells and fuel cell stacks.

In the technical field of polymer electrolyte fuel cells (PEFC), for example, as shown in Patent Document 1, fuel cell gases (anode gas, cathode gas) can be uniformly supplied and diffused. fuel cell stacks are known.

WO2015/072584

In the technical field of fuel cells, there is a demand for improvement in the volumetric energy density of fuel cells, and there is a demand for techniques for thinning the members that constitute them.

The fuel cell of the present invention is a fuel cell in which a cathode gas separator, a membrane electrode assembly, a gas diffusion layer, and an anode gas separator are laminated, and the cathode gas separator is a metal The anode gas separator has a plate and a fuel cell gas supply diffusion layer having a conductive porous body, and the anode gas separator has a first convex portion arranged on one surface thereof and defining a flow path of the anode gas; The membrane electrode assembly has a flow path defining plate disposed on the other surface opposite to the one surface and having a second convex portion that defines a flow path of the coolant, and the membrane electrode assembly is the fuel cell gas supply diffusion plate. and the gas diffusion layer.

Alternatively, the fuel cell of the present invention is a fuel cell in which a cathode gas separator, a membrane electrode assembly, a gas diffusion layer, and an anode gas separator are laminated, wherein the cathode gas separator is a first metal plate having a flat plate-like portion; and a fuel cell gas supply diffusion layer having a conductive porous material; the anode gas separator has a second metal plate; The second metal plate has a first protrusion on one surface and a second protrusion on the other surface opposite to the one surface. A first concave portion serving as a flow path for a coolant is formed on the surface, the second convex portion forms a second concave portion serving as a flow path for the anode gas on the one surface, and the membrane electrode assembly includes the fuel The fuel cell gas supply diffusion layer is arranged between the first metal plate and the membrane electrode assembly, and the gas diffusion layer is arranged between the gas supply diffusion layer for the battery and the gas diffusion layer. The layer is arranged between the second metal plate and the membrane electrode assembly, and the one surface of the second metal plate faces the gas diffusion layer.

According to the fuel cell of the present invention, the anode gas separator is arranged on one surface thereof and on the other surface opposite to the first convex portion that defines the flow path of the anode gas. Compared to the case where the fuel cell has a fuel cell gas supply diffusion layer for the anode gas and a coolant supply diffusion layer for the coolant, since the flow path defining plate has the second convex portion that defines the coolant flow path. As a result, the thickness of the fuel cell, which is a member constituting the fuel cell stack, can be reduced. As a result, the fuel cell stack of the present invention can be made thinner than the conventional fuel cell stack.

Alternatively, according to the fuel cell of the present invention, the second metal plate in the anode gas separator has the first protrusion on one surface and the second protrusion on the other surface opposite to the one surface. The first convex portion forms a first concave portion serving as a coolant flow path on the other surface, and the second convex portion forms a second concave portion serving as an anode gas flow passage on one surface. Therefore, compared to the case where the fuel cell gas supply diffusion layer for the anode gas and the coolant supply diffusion layer for the coolant exist in the fuel cell, it is a member that constitutes the fuel cell stack. A fuel cell can be made thinner. As a result, the fuel cell stack of the present invention can be made thinner than the conventional fuel cell stack.
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a front view schematically showing a fuel cell stack 20 according to Embodiment 1. FIG. 1 is a side view schematically showing a fuel cell stack 20 according to Embodiment 1. FIG. 2 is a plan view of the fuel cell 1 according to Embodiment 1, viewed from the anode gas separator 26 side. FIG. FIG. 4 is a cross-sectional view taken along line A1-A1 of FIG. 3 and a cross-sectional view showing a state in which fuel cells 1 are stacked; 3 is a plan view of the cathode gas separator 24 in Embodiment 1 as viewed from the metal plate 30 side. FIG. 6 is a cross-sectional view taken along line A2-A2 of FIG. 5; FIG. FIG. 4 is a diagram shown for explaining a membrane electrode assembly 81 according to Embodiment 1; FIG. 11 is a plan view of a cathode gas separator 24a in Embodiment 2 as viewed from the metal plate 30 side. FIG. 9 is a cross-sectional view along A3-A3 in FIG. 8; 5 is a diagram showing a planar structure of a gas channel groove 55. FIG. 3A and 3B are diagrams showing a planar structure and a cross-sectional structure of a gas channel groove 55; FIG. 4A and 4B are diagrams showing a planar structure of the gas channel groove 55 at different depth positions; FIG. It is a figure which shows the relationship between 1st rectangular area R1, 2nd rectangular area R2, and overlapping area R3. 11 is a plan view of a cathode gas separator 24b in Embodiment 3, viewed from the metal plate 30 side. FIG. FIG. 11 is a plan view of a cathode gas separator 24c in Embodiment 4 as viewed from the metal plate 30 side. FIG. 11 is a plan view of a cathode gas separator 24d in Embodiment 5 as viewed from the metal plate 30 side. FIG. 17 is a cross-sectional view along A5-A5 in FIG. 16; It is a figure shown in order to demonstrate the flow of cathode gas.

Hereinafter, the fuel cell and fuel cell stack of the present invention will be described in detail using the embodiments shown in the drawings. In addition, each embodiment described below does not limit the invention which concerns on a claim. Also, not all of the elements and their combinations described in each embodiment are essential to the solution of the present invention. In each embodiment, the same reference numerals may be used for components having the same basic configuration and features, and description thereof may be omitted. The figures showing the components of the invention are schematic diagrams and are not necessarily accurate representations of actual dimensions or proportions.

[Embodiment 1]
A fuel cell stack 20 (PEFC: Polymer Electrolyte Fuel Cell) according to Embodiment 1 will be described below.

[Fuel cell stack]
First, the fuel cell stack 20 according to Embodiment 1 will be described.
FIG. 1 shows a front view schematically showing a fuel cell stack 20 according to Embodiment 1. As shown in FIG.
FIG. 2 shows a side view schematically showing the fuel cell stack 20 according to the first embodiment.

In the fuel cell stack 20, a plurality of fuel cells 1 (single cells) are stacked, and the metal plates 30 of adjacent fuel cells 1 and the flow path defining plate 90 are in contact with each other at the top of a second convex portion 94, which will be described later. configured as

Current collecting plates 27A and 27B are arranged at both ends of the stacked fuel cells 1 .
Further, end plates 75 and 76 are arranged outside the current collector plates 27A and 27B via insulating sheets 28A and 28B. Components of the fuel cell 1 are pressed from both sides by end plates 75 and 76 .

1 and 2, the cathode gas separator 24, the membrane electrode assembly 81, the gas diffusion layer 88, the anode gas separator 26, the collector plates 27A and 27B, the insulating sheets 28A and 28B, the end plates 75, 76 are spaced apart for clarity. In practice, they are closely connected to each other in the order of arrangement shown. The joining method is not particularly limited. For example, the end plates 75 and 76 may be joined only by pressing the members from both sides. Alternatively, for example, the members may be joined by bonding appropriate positions of the members with an adhesive and then pressing the members from both sides with the end plates 75 and 76 . Of course, other methods may be used for bonding. The cathode gas separator 24, the membrane electrode assembly 81, the gas diffusion layer 88, the anode gas separator 26, the current collector plates 27A and 27B, the insulating sheets 28A and 28B, etc. have a thickness of, for example, about 100 μm to about 10 mm. is. These constituent elements are drawn with an exaggerated thickness in each drawing in each embodiment 1 of this specification.

An anode gas supply port 71A, a cathode gas discharge port 72B, and a coolant discharge port 73B are provided at one end of the anode-side end plate 75 (in FIG. 2, these are collectively indicated by broken lines). . On the other hand, an anode gas discharge port 71B, a cathode gas supply port 72A, and a coolant supply port 73A are provided at one end of the end plate 76 on the cathode side (the side opposite to the one end of the end plate 75) (Fig. 2, these are also collectively indicated by dashed lines). Corresponding fluid supply pipes and fluid discharge pipes are connected to these supply ports and discharge ports, respectively.

The cathode gas separator 24 and the anode gas separator 26 respectively have an anode gas inlet 61A communicating with the anode gas supply port 71A, a cathode gas (and generated water) outlet 62B communicating with the cathode gas outlet 72B, and , a coolant outlet 63B communicating with the coolant outlet 73B (described later). The cathode gas separator 24 and the anode gas separator 26 are respectively provided with an anode gas outlet 61B communicating with the anode gas outlet 71B, a cathode gas inlet 62A communicating with the cathode gas supply port 72A, and a coolant supply port. A coolant inlet 63A communicating with the port 73A is provided (described later).

A cathode gas, an anode gas and a coolant are supplied through the anode gas supply port 71A, the cathode gas supply port 72A and the coolant supply port 73A. In Embodiment 1, hydrogen gas is used as the anode gas, air is used as the cathode gas, and water is used as the coolant.

[Fuel cell]
Next, the fuel cell 1 according to Embodiment 1 will be described. A fuel cell is a unit that constitutes the fuel cell stack 20, and is a basic component of a fuel cell.
FIG. 3 shows a plan view of the fuel cell 1 according to Embodiment 1 as viewed from the anode gas separator 26 side.
FIG. 4(a) shows a cross-sectional view along A1-A1 in FIG. FIG. 4(b) shows a sectional view showing a state in which the fuel cells 1 are stacked. In addition, in FIGS. 4A and 4B, in order to make the appearance easier to understand, the metal plate (first metal plate) 30 and the flow path defining plate (second metal plate) 90 have cross sections. The cross-sectional structure of the membrane electrode assembly 81 is omitted from illustration. In FIG. 4(b), the metal plate 30 is shown at the top in order to make it easier to understand that the first concave portion 93 serves as a coolant flow path. In FIG. 4(b), the position where the cathode gas flow path (fuel cell gas supply diffusion layer 42) is denoted by C, and the position where the anode gas flow path (second concave portion 95) is denoted by A. , and a location (first concave portion 93) serving as a coolant flow path is indicated by W. As shown in FIG.
FIG. 5 shows a plan view of the cathode gas separator 24 in Embodiment 1 as seen from the metal plate 30 side. 5, illustration of the metal plate 30 is omitted.
FIG. 6 shows a cross-sectional view along A2-A2 in FIG. In order to show the positional relationship between the cathode gas separator 24 and the membrane electrode assembly 81, FIG. 6 shows the cathode gas separator 24 with the membrane electrode assembly 81 joined. In FIG. 6, the cross-sectional structure of the membrane electrode assembly 81 is omitted.

As shown in FIGS. 1 to 6, the fuel cell 1 according to Embodiment 1 includes a cathode gas separator 24, a membrane electrode assembly 81, a gas diffusion layer 88, and an anode gas separator 26 which are laminated. Become.
Here, the cathode gas separator 24 has a metal plate 30 and a fuel cell gas supply diffusion layer 42 having a conductive porous body 40, and the anode gas separator 26 is arranged on one surface thereof. and a channel defining plate 90 having a first convex portion 92 defining a channel for the anode gas and a second convex portion 94 disposed on the other surface opposite to the one surface and defining a channel for the coolant. . The membrane electrode assembly 81 is configured to be disposed between the fuel cell gas supply diffusion layer 42 and the gas diffusion layer 88 .
One surface of the flow path defining plate 90 on which the first projections 92 that define the flow path of the anode gas are arranged is the side on which the gas diffusion layer 88 is arranged (facing the gas diffusion layer 88 side). ) is configured as
The details of each member constituting the fuel cell 1 will be described below.

[Cathode gas separator]
First, the cathode gas separator 24 will be described.
The cathode gas separator 24 has a metal plate 30 and a fuel cell gas supply diffusion layer 42 having a conductive porous body 40, as shown in FIGS.

The cathode gas separator 24 has a structure in which a fuel cell gas supply diffusion layer 42 is formed on one surface (the surface on the membrane electrode assembly 81 side) of the metal plate 30 . The metal plate 30 is preferably a metal made of one or more of Inconel, nickel, gold, silver and platinum, or a metal plating or clad material on an austenitic stainless steel plate. Corrosion resistance can be improved by using these metals.
In addition, in this specification, the metal plate 30 is also called "the 1st metal plate."

In the cathode gas separator 24, a cathode gas inlet 62A, a coolant inlet 63A, and an anode are provided in the order of right, center, and left in FIG. A gas outlet 61B is provided. At the other end (upper part in FIG. 5), a cathode gas outlet 62B, a coolant outlet 63B, and an anode gas inlet 61A are provided in this order from left to right in FIG.

The inflow ports 61A, 62A, 63A, the outflow ports 61B, 62B, 63B, and the areas where the fuel cell gas supply diffusion layer 42 is formed are surrounded by electronically conductive or non-electronically conductive dense frames 32. being surrounded. The dense frame 32 in the cathode gas separator 24 prevents leakage of the cathode gas. Along the dense frame 32, the outer surface of the dense frame 32 surrounds the formation areas of the inlets 61A, 62A, 63A, the outlets 61B, 62B, 63B, and the fuel cell gas supply diffusion layer 42. A groove is formed. A gasket 33 (a sealing material such as a packing or an O-ring) is arranged in this groove.

On both sides of the metal plate 30, except for the portions where the inlets 61A, 62A, 63A and the outlets 61B, 62B, 63B are provided, a corrosion-resistant layer ( not shown) are formed. A corrosion-resistant layer may be formed on the inner peripheral surfaces of the inlets 61A, 62A, 63A and the outlets 61B, 62B, 63B. Corrosion-resistant layers may be formed on the side surfaces and end surfaces of the metal plate 30 . The corrosion-resistant layer is preferably a dense layer having the same composition as the dense frame 32 and has the effect of suppressing corrosion of the metal plate 30 . At the stage of composing the fuel cell stack 20 by combining the fuel cells 1, the gasket 33 is in close contact with other fuel cell separators, the membrane electrode assembly 81, the current collector plates 27A and 27B, etc. to be joined, and the fluid flow. Control leakage.

In Embodiment 1, the metal plate 30 is at least partially provided with a flat plate-like portion extending over both sides of the metal plate 30 .
In the cathode gas separator 24, a fuel cell gas supply/diffusion layer 42 for supplying and diffusing the cathode gas is formed in a plate-like portion formed in the center of one surface of a rectangular metal plate 30 as a substrate. ing.
In addition, the metal plate 30 has the fuel cell gas supply diffusion layer 42 formed on a flat portion provided on the flat metal plate, and the portion other than the portion where the fuel cell gas supply diffusion layer 42 is formed. The respective inlets 61A, 62A, 63A and respective outlets 61B, 62B, 63B are provided in the portion.
In the fuel cell gas supply diffusion layer 42, one or a plurality of gas pressure equalizing grooves (see FIG. 14 to be described later) are formed over the entire width direction orthogonal to the direction from the inflow side to the outflow side of the cathode gas. may be formed.

Air (oxygen gas and nitrogen gas) as a cathode gas diffuses inside the conductive porous body 40 . The porous body 40 contains a mixture of a conductive material (preferably a carbon-based conductive material) and a polymer resin. By mixing the carbon-based conductive material with the polymer resin, high conductivity can be imparted to the polymer resin, and the moldability of the carbon material can be improved due to the binding property of the polymer resin. The fluid resistance of the fuel cell gas supply diffusion layer 42 depends on the porosity of the porous body 40 and the area of the fluid flowing surface. The higher the porosity, the lower the fluid resistance. The larger the area through which the fluid flows, the smaller the fluid resistance. As a rough guideline, the porosity of the porous body 40 is preferably about 50 to 85%.

By adjusting the content of the carbon-based conductive material, the porosity of the porous body 40 can be adjusted, and the movement resistance in the fuel cell gas supply diffusion layer 42 can be adjusted. In particular, when the content of the carbon-based conductive material is increased, the transfer resistance is decreased (porosity is increased). Conversely, when the content of the carbon-based conductive material is decreased, the migration resistance increases (the porosity decreases). The corrosion-resistant layer and the dense frame 32 are also a mixture of a carbon-based conductive material and a polymer resin, and are preferably densified while ensuring electrical conductivity by an appropriate content of the carbon-based conductive material.

Although the carbon-based conductive material is not particularly limited, for example, graphite, carbon black, diamond-coated carbon black, silicon carbide, titanium carbide, carbon fiber, carbon nanotube, etc. can be used. Both thermosetting resins and thermoplastic resins can be used as the polymer resin. Examples of polymer resins include phenolic resins, epoxy resins, melamine resins, rubber resins, furan resins, vinylidene fluoride resins, and the like.

An inflow passage 57 is formed between the cathode gas inlet 62A and the region where the porous body 40 is formed. An outflow passage 58 is formed between the cathode gas outflow port 62B and the region where the porous body 40 is formed. These inflow passages 57 and outflow passages 58 are for supporting the membrane electrode assembly 81 or its frame. Therefore, any structure may be used as long as the cathode gas can flow smoothly and the membrane electrode assembly 81 can be supported. For example, it may be a porous layer with a very large porosity, or a structure in which a large number of struts are arranged.
An elongated gas inflow side groove 51 is formed along the width direction of the metal plate 30 in a region facing the inflow passage 57 in the fuel cell gas supply diffusion layer 42 . In addition, an elongated gas outflow groove 52 is also formed along the width direction of the metal plate 30 in a region facing the outflow passage 58 in the fuel cell gas supply diffusion layer 42 . However, the gas inflow side groove 51 and the gas outflow side groove 52 may be omitted.

The fuel cell gas supply diffusion layer 42 , the inflow passage 57 , and the outflow passage 58 are formed at the same height (thickness) as the dense frame 32 .

The lateral width of the fuel cell gas supply diffusion layer 42 in Embodiment 1 is, for example, about 30 mm to 300 mm, depending on the type and size of the transportation equipment when it is used in a fuel cell for transportation equipment. The thickness of the fuel cell gas supply diffusion layer 42 is, for example, about 150 to 400 μm. When the fuel cell gas supply diffusion layer 42 according to Embodiment 1 is used in fuel cells for applications other than transportation equipment (for example, for stationary use), the size is not limited to the above size, and the required performance, etc. A suitable size can be used depending on the application. The above sizes are the same for each embodiment described later.

When the fuel cell stack 20 is operated, protons (H ⁺ ) are generated at the fuel electrode into which the anode gas (hydrogen gas) is introduced. The protons diffuse through the membrane electrode assembly 81 from the anode gas separator 26, move to the oxygen electrode side, and react with oxygen to produce water. The produced water is discharged from the oxygen electrode side.

The air diffuses in the thickness direction while diffusing in the planar direction in the fuel cell gas supply diffusion layer 42, and is supplied to the membrane electrode assembly 81 provided in contact with the fuel cell gas supply diffusion layer 42, Contributes to the power generation reaction. Gases not used for power generation (unused oxygen gas and nitrogen gas) and water (steam or condensed water) generated during power generation flow out to the outflow passage 58 via the porous body 40 and the gas outflow side groove 52 . The oxygen gas, nitrogen gas and water that have flowed out to the outflow passage 58 are finally discharged from the outflow passage 58 through the cathode gas outlet 62B and the cathode gas outlet 72B. At this time, due to the structure of the fuel cell gas supply diffusion layer 42 , not all of the water is discharged, and part of it remains in the porous body 40 of the fuel cell gas supply diffusion layer 42 .

[Manufacturing Method of Cathode Gas Separator 24]
As an example, the corrosion-resistant layer, dense frame 32, fuel cell gas supply diffusion layer 42, and the like are formed by isostatic pressing. For example, when a thermosetting resin is used (thermoplastic resin may be used), carbon-based conductive material powder (and carbon fiber depending on the situation), resin powder and volatile solvent are kneaded to form a paste. Various types of this paste are prepared, such as those for the corrosion-resistant layer, the dense frame, and the fluid supply diffusion layer. Then, the corrosion-resistant layer, the pattern of the dense frame 32, the pattern of the fuel cell gas supply diffusion layer 42, and the like are sequentially formed on the metal plate 30 by printing, stamping, squeezing, or the like. The solvent is volatilized after forming each pattern. Put the entire metal plate 30 with all the above patterns formed into a soft thin rubber bag, degassed into a vacuum, put the rubber bag into a pressure-resistant container, introduce a heating fluid into the container, and The resin is hardened by applying isotropic pressure with . In order to finally make the height (thickness) of the dense frame 32 and the gas supply diffusion layer 42 for fuel cells the same height (thickness), each of these is adjusted according to the degree of shrinkage during curing of the resin. It is preferable to adjust the height (thickness) of the frame, wall, layer, etc. at the time of pattern production.

On the one hand, the corrosion-resistant layer is formed on the metal plate 30, and on the other hand, the dense frame 32 and the gas supply diffusion layer 42 for the fuel cell are formed, and finally these are bonded by thermocompression. At this time, the dense frame 32 may be formed simultaneously with the corrosion-resistant layer on the metal plate 30 . In the first step, the corrosion-resistant layer and the dense frame 32 are formed on the metal plate 30. Then, in the second step, the paste of the fuel cell gas supply diffusion layer 42 is sequentially printed on the corrosion-resistant layer of the metal plate 30 and dried. It can also be manufactured by hardening with a roll press (hot press) after curing.

Alternatively, the following manufacturing method can also be used. Carbon fiber (CF), a small amount of black smoke fine particles (GCB), and a thermoplastic or thermosetting binder or a resin that forms a fibrous material are kneaded to form a sheet, and the green before curing. In the sheet state, a stamp die having projections having shapes corresponding to the inflow passage 57, the outflow passage 58, the gas inflow side groove 51 and the gas outflow side groove 52 is pressed against the sheet to form the inflow passage 57, the outflow passage 58 and the gas inflow passage. A side ditch 51 and a gas outflow side ditch 52 are formed. Finally, the green sheet is heat-treated and adhered to the metal plate 30 on which the corrosion-resistant layer is formed.

The movement resistance (or fluid resistance) of the fuel cell gas supply diffusion layer 42 depends on the porosity of the porous body 40 and the area of the surface perpendicular to the fluid flow direction (height (thickness) and width of each layer). do. The higher the porosity, the lower the transfer resistance. As the area through which the fluid flows increases, the movement resistance decreases (the movement resistance per unit area is constant). As a rough guideline, the porosity of the gas supply diffusion layer for the fuel cell is about 30 to 85% for the porous body 40 . The porosity P is determined by P=(volume of pores in the porous layer)/(volume of the porous layer), which is easy to measure. Here, the pores are true pores including pores that do not communicate with the outside.

The manufacturing method described above is applied to the cathode separator according to each embodiment described later (a cathode separator having a gas supply diffusion layer for a fuel cell having grooves for gas flow paths, grooves for equalizing gas pressure, isolated holes, etc.). can be applied by making the shape of the fuel cell gas supply diffusion layer or its precursor into a shape corresponding to the shape of the fuel cell gas supply diffusion layer in the cathode separator according to each embodiment. be able to.

[Membrane electrode assembly]
Next, the membrane electrode assembly 81 will be explained.
FIG. 7 shows a diagram for explaining the membrane electrode assembly 81 according to the first embodiment. Here, FIG. 7(a) is a plan view of the membrane electrode assembly 81, FIG. 7(b) is a front view of the membrane electrode assembly 81, and FIG. 7(c) is a side view of the membrane electrode assembly 81. each shown.

The membrane electrode assembly 81 is disposed between the fuel cell gas supply diffusion layer 42 and the gas diffusion layer 88, as shown in FIGS.
As shown in FIG. 7, the membrane electrode assembly 81 includes an electrolyte membrane (PEM) 82, catalyst layers (CL) 85 arranged on both sides of the electrolyte membrane 82, and outer surfaces of each catalyst layer 85. and a coated microporous layer (MPL) 83 .

In Embodiment 1, the electrolyte membrane 82 and the catalyst layers 85 arranged on both sides thereof are called a catalyst coated electrolyte membrane (CCM).
In Embodiment 1, as shown in FIG. 7, the microporous layer 83 is arranged both between the cathode gas separator 24 and the membrane electrode assembly 81 and between the gas diffusion layer 88 and the membrane electrode assembly 81. It is The microporous layer 83 has finer pores (pores) than the fuel cell gas supply diffusion layer 42 of the cathode gas separator 24 .

The microporous layer 83 may be arranged either between the cathode gas separator 24 and the membrane electrode assembly 81 or between the gas diffusion layer 88 and the membrane electrode assembly 81 . Also, the microporous layer 83 can be omitted.

[Gas diffusion layer]
Next, the gas diffusion layer 88 will be explained.
The gas diffusion layer 88 is arranged between the membrane electrode assembly 81 and the anode gas separator 26, as shown in FIGS.
The gas diffusion layer 88 is a porous body for diffusing and supplying the anode gas. The gas diffusion layer 88 is made of carbon paper, for example. Also, the gas diffusion layer 88 may be made of carbon cloth, carbon felt, or a porous metal material.

[Anode gas separator]
Next, the anode gas separator 26 will be described.
The anode gas separator 26, as shown in FIGS. It has a channel defining plate 90 having a second projection 94 arranged to define a coolant channel.
The flow path defining plate 90 has a plurality of first protrusions 92 and a plurality of second protrusions 94 .
"Defining a flow path" means forming a flow path by interrupting the flow of a fluid. It can also be said that the first protrusion 92 and the second protrusion 94 are walls that block the flow of fluid.

The flow path defining plate 90 in the first embodiment is, for example, a metal plate having a corrugated portion.
In this specification, the flow path defining plate 90, which is a metal plate having a corrugated portion, is also referred to as a “second metal plate”.
On the back side of the first convex portion 92, there is a first concave portion 93 that serves as a coolant flow path.
On the back side of the second convex portion 94, there is a second concave portion 95 that serves as a channel for the anode gas.
In addition, in FIG. 3, the height and width of the first protrusion 92 and the second protrusion 94 are exaggerated. In practice, the interval between the first protrusions 92 and the second protrusions 94 may be narrower, or the number thereof may be increased.

Alternatively, the flow path defining plate 90 has a first convex portion 92 on one surface and a second convex portion 94 on the other surface opposite to the one surface. , and a first recessed portion 93 that serves as a flow path for the coolant is formed on the other surface, and the second convex portion 94 is configured to form a second recessed portion 95 that serves as a flow path for the anode gas on one surface.
Therefore, in the A1-A1 cross section of FIG. 3, which crosses the flow path of the second concave portion 95 that serves as the anode gas flow path, the flow path defining plate 90 has a corrugated shape (see FIG. 4).

In the first embodiment, the anode gas flow path defined by the first projections 92 and the coolant flow path defined by the second projections 94 are linear (see FIG. 3). In the present invention, the shape of the flow path defined by each projection is not limited to a straight line, and may be curved or meandering.

In the first embodiment, the anode gas flow path defined by the first projections 92 and the coolant flow path defined by the second projections 94 have a substantially trapezoidal shape when viewed in cross section (see FIG. 4). ). In the present invention, the flow path defined by the projections may have a polygonal shape other than a trapezoid when viewed in cross section, or may have a curved shape.

The fuel cell 1 in Embodiment 1 is assumed to be used as a fuel cell stack 20 as shown in FIGS. 1 and 2 . In the fuel cell 1, the first concave portion 93, which serves as a flow path for the coolant, is open. contact with the metal plate 30 (collector plate 27A at the top) of the fuel cell 1 (see FIG. 4(b)). Therefore, the first concave portion 93 becomes a closed flow path during actual use.

The anode gas separator 26 is provided with a spacer 91 formed around it so that the end thereof is at the same height as the second convex portion 94 . The spacer 91 prevents refrigerant from leaking from the anode gas separator 26 .
The spacer 91 is arranged on the convex side of the first convex portion 92 and the second convex portion 94 when viewed from the end portion of the flow path defining plate 90 . In Embodiment 1, the second convex portion 94 side is convex when viewed from the end portion of the flow path defining plate 90 . When the first convex portion 92 side is convex when viewed from the end portion of the flow path defining plate 90, the spacer 91 is arranged on the side where the first convex portion 92 is convex.
The spacer 91 may be integrated with the metal plate 30 or may be separate. Instead of the spacer 91, it may have a protrusion adjusted to have the same height as the second protrusion 94. FIG.

The metal material constituting the flow path defining plate 90, which is a metal plate, may be a metal made of one or more of Inconel, nickel, gold, silver, and platinum, or a metal plating or clad material on an austenitic stainless steel plate. preferable. Corrosion resistance can be improved by using these metals. Further, since the flow path defining plate 90 is in contact with the metal plate 30 when the fuel cell stack 20 is formed, the metal material forming the flow flow defining plate 90 is the same as the metal material forming the metal plate 30. is preferably used.
The flow path defining plate 90 in Embodiment 1 can be formed by press working, for example.

It is preferable to use a metal material for the flow path defining plate 90 mainly because of the manufacturing cost problem. may be
In addition, the first convex portion 92 and the second convex portion 94 are preferably formed by press working mainly from the viewpoint of mass productivity and manufacturing cost. good too.

The effects of the fuel cell 1 and the fuel cell stack 20 according to Embodiment 1 will be described below.

According to the fuel cell unit 1 according to Embodiment 1, the anode gas separator 26 includes the first convex portion 92 arranged on one surface thereof and defining the flow path of the anode gas, and the other surface opposite to the one surface. Since the fuel cell 1 has the flow path defining plate 90 having the second convex portion 94 that defines the flow path of the coolant, the fuel cell gas supply diffusion layer for the anode gas and the coolant supply layer for the coolant in the fuel cell 1 are provided. A fuel cell can be made thinner than when a diffusion layer exists. As a result, the fuel cell stack 20 of the fuel cell stack 1 according to the first embodiment can be thinner than the conventional fuel cell stack.

It should be noted that the fuel cell of the present invention does not have members corresponding to the fuel cell gas supply diffusion layer and coolant supply diffusion layer in the separator of the conventional fuel cell. However, as a result of intensive research by the inventors of the present invention, even in a fuel cell in which the fuel cell gas supply diffusion layer and coolant supply diffusion layer are not present in the anode gas separator, the following (1) to It was found that high power generation efficiency can be maintained for the reason (4).

(1) The fuel cell gas supply diffusion layer in the cathode gas separator can efficiently discharge the water vapor or condensed water by dispersing the water vapor or condensed water generated in the membrane electrode assembly during power generation. It has the effect of being able to On the other hand, since the anode gas separator is not required to have drainage properties, there is no effect even if the fuel cell gas supply diffusion layer does not exist in the anode gas separator from this point of view.

(2) By a simple means such as increasing the flow rate of the refrigerant, it is easy to ensure the same cooling capacity as in the case where the refrigerant supply diffusion layer exists. Although the fuel cell stack of the present invention is thinner than the conventional fuel cell stack, each fuel cell has a coolant channel (Figs. 1, 2 and 3). See Figure 4). Therefore, it is easy to ensure the cooling capacity from this point of view as well.

(3) Hydrogen is usually used as the anode gas. Since hydrogen has a small molecular weight, it has high diffusibility, and even if there is no gas supply diffusion layer for a fuel cell, it has little effect on supply and diffusion.

(4) Electric resistance can be reduced by reducing the number of members constituting the fuel cell.

For the reasons (1) to (4) above, high power generation efficiency can be maintained even when the fuel cell does not have the fuel cell gas supply diffusion layer and the coolant supply diffusion layer.

In addition, in the fuel cell 1 according to Embodiment 1, the fuel cell gas supply diffusion layer 42 having the porous body 40 is formed on the cathode gas separator 24 itself. It can diffuse uniformly over the entire surface of the supply diffusion layer 42 . As a result, according to the fuel cell 1 according to Embodiment 1, compared to a fuel cell in which both the anode gas side separator and the cathode gas side separator are flow path defining plates (corrugated metal plates), Cathode gas can be supplied uniformly over the entire surface of the membrane electrode assembly 81, and the power generation efficiency of the fuel cell can be increased.

Further, according to the fuel cell unit 1 according to Embodiment 1, the flow path defining plate 90, which is the second metal plate, has the first convex portion 92 on one surface thereof and the convex portion 92 on the opposite side thereof. A second convex portion 94 is arranged on the other surface, the first convex portion 92 forms a first concave portion 93 that serves as a coolant flow path on the other surface, and the second convex portion 94 is formed on the one surface. Since the fuel cell 1 is configured to form the second concave portion 95 that serves as the flow path of the anode gas, the fuel cell 1 may have a fuel cell gas supply diffusion layer for the anode gas and a coolant supply diffusion layer for the coolant. In comparison, the fuel cell can be made thinner. As a result, the fuel cell stack 20 of the fuel cell stack 1 according to the first embodiment can be thinner than the conventional fuel cell stack.

Another expression for the thinning of the fuel cell is as follows. In the fuel cell unit 1 according to the first embodiment, the anode gas separator 26 is a channel defining plate having a first convex portion 92 defining the channel of the anode gas and a second convex portion 94 defining the channel of the coolant. Since 90 is used, there is no need to separately prepare a structure (refrigerant supply diffusion layer) for circulating the refrigerant. Therefore, the fuel cell 1 according to Embodiment 1 can be made thinner than the fuel cells constituting the conventional fuel cell stack.

Another factor that can reduce the thickness of the fuel cell 1 according to Embodiment 1 is as follows. A fuel cell in a conventional fuel cell stack consists of (1) a metal plate for a cathode gas separator, (2) a gas supply diffusion layer for cathode gas, (3) a membrane electrode assembly, (4) a gas for anode gas It consists of six parts: a supply diffusion layer, (5) an anode separator metal plate, and (6) a refrigerant diffusion layer. On the other hand, the fuel cell 1 according to Embodiment 1 substantially includes (1) a metal plate 30, (2) a fuel cell gas supply diffusion layer 42 (cathode gas gas supply diffusion layer), and (3) a membrane electrode. (4) a gas diffusion layer 88 (gas supply diffusion layer for anode gas); and (5) a flow path defining plate 90. Thus, the fuel cell 1 according to Embodiment 1 can reduce the number of parts compared to the fuel cell in the conventional fuel cell stack, and as a result, it can be made thinner.

Further, when comparing the fuel cell 1 according to Embodiment 1 with a fuel cell in which metal plates having corrugated portions are arranged on both the cathode gas side and the anode gas side, the fuel cell 1 according to Embodiment 1 In the fuel cell 1, since the cathode gas separator 24 having the fuel cell gas supply diffusion layer 42 is arranged on the cathode side, the structure on the cathode side can be made thinner even if the structure on the anode side is the same. can. From this point of view as well, it has been confirmed that the fuel cell 1 can be made thinner.

Further, according to the fuel cell 1 according to Embodiment 1, the cathode gas flow path (fuel cell gas supply diffusion layer 42), the anode gas flow path (second concave portion 95), and the coolant flow path (first Since the recessed portion 93) is provided, there is no need to use various types of separators and the like as in conventional fuel cells, and the structure can be simplified.

Further, according to the fuel cell unit 1 according to Embodiment 1, the flow path defining plate 90 is made of a metal plate, and the first concave portion 93 serving as the coolant flow path is present on the back side of the first convex portion 92 . Since the second concave portion 95 serving as the anode gas flow path exists on the back side of the second convex portion 94, the anode gas separator 26 can be easily manufactured by press working.

Further, according to the fuel cell 1 according to Embodiment 1, at least one of between the cathode gas separator 24 and the membrane electrode assembly 81 and between the gas diffusion layer 88 and the membrane electrode assembly 81 has: Since the microporous layer 83 is arranged, it is possible to manage the moisture inside the fuel cell 1 .

The fuel cell stack 20 according to Embodiment 1 is formed by stacking the fuel cells 1 according to Embodiment 1, and the metal plate 30 and the flow path defining plate 90 of the adjacent fuel cells 1 form a second convex portion 94. Since the fuel cell 1 according to the first embodiment is used, the fuel cell stack can be made thinner than the conventional fuel cell stack.

The above Patent Document 1 describes a fuel cell stack having a structure in which gas supply diffusion layers for a fuel cell are arranged on both the cathode gas side and the anode gas side. A conventional fuel cell stack can be made thinner than a fuel cell stack in which metal plates having corrugated portions are arranged on both electrodes. However, the conventional fuel cell stack requires a structure (refrigerant supply diffusion layer) for circulating the refrigerant in addition to the fuel cell gas supply diffusion layer. In the fuel cell stack 20 according to the first embodiment, the anode gas separator 26 has a flow path definition having a first projection 92 that defines the flow path of the anode gas and a second projection 94 that defines the flow path of the coolant. Since the plate 90 is used, there is no need to separately prepare a coolant supply diffusion layer. Therefore, the fuel cell stack 20 according to Embodiment 1 becomes a fuel cell stack that can be made thinner than the conventional fuel cell stack.

Another factor that can reduce the thickness of the fuel cell stack 20 according to the first embodiment is as follows. In a conventional fuel cell stack, when assuming a fuel cell unit including cooling, (1) a metal plate for a cathode gas separator, (2) a gas supply diffusion layer for a cathode gas, (3) a membrane electrode Six parts are required: a joined body, (4) a gas supply diffusion layer for anode gas, (5) a metal plate for anode separator, and (6) a diffusion layer for refrigerant. On the other hand, in the fuel cell stack 20 according to Embodiment 1, the fuel cell 1 substantially consists of (1) a metal plate 30, (2) a fuel cell gas supply diffusion layer 42 (cathode gas gas supply diffusion layer). layer), (3) membrane electrode assembly, (4) gas diffusion layer 88 (gas supply diffusion layer for anode gas), and (5) channel defining plate 90 . As described above, the fuel cell stack 20 according to Embodiment 1 can reduce the number of parts compared to the conventional fuel cell stack, and as a result, the fuel cell stack can be made thinner than the conventional fuel cell stack. It becomes a battery cell stack.

Further, when comparing the fuel cell stack 20 according to Embodiment 1 with a fuel cell stack using a metal plate having corrugated portions on both the cathode gas side and the anode gas side, the fuel cell stack 20 according to Embodiment 1 Since the cathode gas separator 24 having the fuel cell gas supply diffusion layer 42 on the cathode side is used in the fuel cell stack 20 according to the above, the structure on the cathode side can be made thinner even if the structure on the anode side is the same. is. From this point of view as well, it has been confirmed that the fuel cell stack 20 can be made thinner.

[Embodiment 2]
FIG. 8 shows a plan view of the cathode gas separator 24a in Embodiment 2 as viewed from the metal plate 30 side. In FIG. 8, the illustration of the metal plate 30 is omitted in order to clearly show the flow path pattern of the cathode gas separator 24a. The same applies to FIGS. 14 to 16, which will be described later.
FIG. 9 shows a cross-sectional view along A3-A3 in FIG. In order to show the positional relationship between the cathode gas separator 24a and the membrane electrode assembly 81, FIG. 9 shows the cathode gas separator 24a with the membrane electrode assembly 81 joined. A cross-sectional structure of the membrane electrode assembly 81 is omitted.
FIG. 10 shows the planar structure of the gas channel groove 55 .
FIG. 11 shows the planar structure and cross-sectional structure of the gas channel groove 55 . 11(a) is a plan view, and FIG. 11(b) is a cross-sectional view taken along line A4-A4 of FIG. 11(a).
FIG. 12 shows the planar structure of the gas channel groove 55 at different depth positions. FIG. 12(a) shows the planar structure of the gas channel groove 55 at the depth position D1 (the depth position on the surface of the porous body 40 (or the gas channel groove 55)), and FIG. 12(c) shows the planar structure of the gas flow channel groove 55 at the depth position D2 (the depth position half the depth of the gas flow channel groove 55), and FIG. 2 shows the planar structure of the gas channel groove 55 at the depth position at the bottom of the gas channel 55. FIG.
10 and 11, reference numeral 55 indicates gas flow channel grooves, reference numeral 55A indicates one gas flow channel groove among the gas flow channel grooves 55, and reference numeral 55B indicates one gas flow channel groove 55A. shows the grooves for the gas flow path adjacent to the . Therefore, the one gas flow channel groove 55A is also the gas flow channel groove 55, so it may be referred to as the gas flow channel groove 55 (55A). Since the channel groove 55B is also the gas channel groove 55, it may be denoted by the reference numeral gas channel groove 55 (55B).
Further, in FIG. 10, the area surrounded by the thick solid line is the first rectangular area R1, and the area surrounded by the thick broken lines on the left and right of the first rectangular area R2 is the second rectangular area R2. The region where the region R2 overlaps is the overlapping region R3, which is shown in a darker color. Reference character R denotes a rectangular region circumscribed by each of the plurality of gas flow channel grooves 55, and reference character R1 denotes a first rectangular region circumscribed by one of the gas flow channel grooves 55A. , reference symbol R2 indicates a second rectangular region circumscribed by the gas flow channel groove 55B adjacent to one gas flow channel groove 55A, and reference symbol R3 indicates an overlap in which the first rectangular region R1 and the second rectangular region R2 overlap. indicate the area.
11 and 12 illustrate the flow of the cathode gas. In FIGS. 11A and 12, the arrows in the gas channel groove 55 indicate the flow along the gas channel groove 55, and the vertical upward arrows in the porous body 40 indicate the gas channel. This is the flow of the cathode gas (underflow gas flow) pushed out from the groove 55 into the porous body 40 (gas diffusion layer). Further, in FIG. 11(b), the horizontal and downward (toward the membrane electrode assembly side) arrows drawn in the porous body 40 are extruded into the porous body 40 from the gas channel grooves 55. 2 shows the cathode gas flow.
FIG. 13 shows the relationship between the first rectangular region R1, the second rectangular region R2 and the overlapping region R3.

The fuel battery cell according to Embodiment 2 basically has the same configuration as the fuel battery cell 1 according to Embodiment 1, but the configuration of the cathode gas separator is the fuel battery cell 1 according to Embodiment 1. different from
The fuel cell according to the second embodiment (not shown in its entirety) will be described below, focusing on differences from the fuel cell 1 according to the first embodiment. Also, the description of the matters described in the first embodiment will be omitted as appropriate.

The fuel cell gas supply diffusion layer 42a according to Embodiment 2 further has a plurality of gas channel grooves 55 for flowing the cathode gas.
More specifically, in the fuel cell according to the second embodiment, as shown in FIG. 8, the fuel cell gas supply diffusion layer 42a in the cathode gas separator 24a is one of the fuel cell gas supply diffusion layers 42a. It further has a plurality of gas channel grooves 55 that are parallel to each other on the plane and each formed in a zigzag or waved manner from the cathode gas inflow side to the outflow side. In the fuel cell according to Embodiment 2, the plurality of gas channel grooves 55 are formed in a zigzag pattern.
Then, as shown in FIGS. 10 to 12, in a plan view, one of the rectangular regions R circumscribing each of the gas flow channel grooves 55 out of the plurality of gas flow channel grooves 55 has one gas flow path. A first rectangular region R1 circumscribed by the channel groove 55 (55A) and a second rectangular region R2 circumscribed by the gas channel groove 55 (55B) adjacent to one gas channel groove 55 (55A). are overlapped along their contacting regions, and the overlap region R3 where the first rectangular region R1 and the second rectangular region R2 overlap is the same as the plurality of gas flow channels regardless of the cross-sectional shape of the plurality of gas flow channel grooves 55. It exists at any depth position of the road groove 55 .
The cathode gas separator 24a will be described below.

The fuel cell gas supply diffusion layer 42a in the second embodiment consists of a conductive sheet-like porous body 40 through which the cathode gas can permeate and diffuse, and one of the fuel cell gas supply diffusion layer 42a. It has a plurality of gas channel grooves 55 which are parallel to each other on the plane and each formed in a zigzag or wavy shape from the cathode gas inflow side to the outflow side. It can also be said that the porous body 40 is a gas diffusion layer.

In a plan view, one of the plurality of rectangular regions R circumscribed by each gas flow channel groove 55 out of the plurality of gas flow channel grooves 55 circumscribes one gas flow channel groove 55 . A rectangular region R1 and a second rectangular region R2 circumscribed by a gas flow channel groove adjacent to one gas flow channel groove overlap along the contact region (see FIGS. 10 and 13). Moreover, the overlapping region R3 where the first rectangular region R1 and the second rectangular region R2 overlap each other is the depth position D1, It also exists in D2 and D3 (see FIGS. 11 and 12).

In the present specification, the term "rectangular region" refers to a rectangular region R (see FIGS. 10 and 11) that is circumscribed by each gas flow channel groove among a plurality of gas flow channel grooves. One or a plurality of gas pressure equalizing grooves are formed in the body 40 over the entire width direction orthogonal to the direction from the cathode gas inflow side to the outflow side so as to intersect with the plurality of gas flow channel grooves. 14, which will be described later), the rectangular regions R formed in the regions divided by the gas pressure equalizing grooves are also different in width and/or length. However, it shall be included in the rectangular area of the present invention. In the present specification, the term "underflow region" refers to a region of the rectangular region excluding the gas channel grooves 55, and in the underflow region, most of the gas flows along the shortest distance toward the outflow side. It will flow along the route.

In the present specification, "from the cathode gas inflow side to the outflow side" means "approximately along the direction in which the cathode gas flows", and "from the cathode gas inflow side to the outflow side". ' direction is the direction of gas flow in the fuel cell gas supply diffusion layer 42a when the fuel cell gas supply diffusion layer 42a is viewed as a whole. This is because when the cathode gas inlet 62A and the cathode gas outlet 62B are arranged diagonally on the metal plate 30 as in the fuel cell gas supply diffusion layer 42a according to the second embodiment, the gas The flow path does not need to be formed along the above-described diagonal line, and the direction "from the inflow side of the cathode gas to the outflow side" as in the second embodiment corresponds to "the fuel cell gas supply diffusion layer 42a as a whole." When the flow direction of the cathode gas in the fuel cell gas supply diffusion layer 42a when viewed is from the bottom to the top of the paper surface of FIG. The gas channel grooves may be formed along the vertical direction from the bottom to the top, or may be formed along other directions.

Here, any two adjacent porous bodies 40 formed in the portion sandwiched between the gas inflow side groove 51 or the gas outflow side groove 52 and the end of the porous body 40, the gas inflow side groove 51, or the gas outflow side groove 52 so as to communicate with the ends or grooves (in other words, between any two adjacent porous body 40 ends or grooves (51, 52) of the plurality of grooves (51, 52) and the porous body 40 ends) For each of a plurality of gas flow channel grooves 55 formed in parallel and arranged so as to communicate with the ends or grooves (51, 52) of the two adjacent porous bodies 40, this gas flow A rectangular region R is defined as a rectangular region circumscribed by the road groove 55 . Therefore, as described above, "the first rectangular region R1 and the second rectangular region R2 overlap along the contacting region", that is, as shown in FIG. When the arrangement pitch L2 of (rectangular regions R) and the width L of the rectangular regions R (the first rectangular region R1 and the second rectangular region R2) satisfy the relationship L2<L, adjacent zigzag gas The configuration is such that one valley side of the channel groove 55 protrudes from the other crest side to such an extent that the channels do not overlap each other. Note that the end portion of the porous body 40 includes the vicinity of the end of the porous body 40 .

In the fuel cell gas supply diffusion layer 42a according to Embodiment 2, the width L1 of the overlapping region R3 and the width L of the rectangular regions R (the first rectangular region R1 and the second rectangular region R2) are such that "L1≧0. It is preferable to satisfy the relationship "1 × L", it is more preferable to satisfy the relationship "L1 ≥ 0.2 × L", and it is even more preferable to satisfy the relationship "L1 ≥ 0.3 × L" (Fig. 11 reference.).

Air (oxygen gas and nitrogen gas) as cathode gas diffuses in the porous body 40 (gas diffusion layer). As a rough guideline, the porosity of the porous body 40 is about 50 to 85%.
Since the porosity of the porous body 40 is configured as described above, the cathode gas between the gas flow channel groove 55 and the porous body 40 passes through the inner surface of the gas flow channel groove 55, As a result of proper circulation of water vapor and condensed water, a large amount of fuel cell gas can be uniformly supplied to the membrane electrode assembly, and cathode gas not used during power generation and power generation Steam and condensed water that are sometimes generated can be efficiently discharged to the outside of the gas channel groove 55 . As a result, there is no need to form, on the inner surface of the gas channel groove 55, a gas-permeable filter in which a large number of fine gas flow holes are formed in a gas-impermeable layer made of metal, ceramics, resin, or the like.

The surface of the fuel cell gas supply diffusion layer 42a facing the metal plate 30 is provided with a plurality of gas channel grooves 55 formed of voids. A plurality of gas flow channel grooves 55 are formed in the gaps with 30 . A plurality of gas channel grooves 55 are formed at predetermined intervals. Each gas channel groove 55 communicates with the inflow passage 57 via the gas inflow groove 51 on the inflow side, and communicates with the outflow passage 58 via the gas outflow groove 52 on the outflow side. The number and structure of the gas channel grooves 55 are not limited to those illustrated.

When the fuel cell gas supply diffusion layer 42a in Embodiment 2 is used in a fuel cell for transportation equipment, the width W of the gas channel groove 55 is For example, it is about 0.3 mm to 2 mm. The depth of the gas channel groove 55 is, for example, about 100 to 300 μm, and the distance (ceiling thickness) between the bottom of the gas channel groove and the other surface of the porous body 40 is, for example, about 100 to 300 μm. As shown in FIG. 8, the gas channel groove 55 has a zigzag shape. That is, the gas channel groove 55 has a straight portion 55a and a corner portion 55b that changes the direction of air flow. The length of the straight portion 55a and the angle of the corner portion 55b are not limited to those illustrated. For example, although the angle of the corner portion 55b is substantially right in FIG. 8, it may be an acute angle or an obtuse angle. Also, the corners 55b may be chamfered or rounded as appropriate.
In addition, both the forming angles of the inflow side end and the outflow side end of the gas flow channel groove 55 are parallel to the direction from the gas inflow side to the outflow side (longitudinal direction of the metal plate 30). It may be. Furthermore, the inflow-side end and the outflow-side end of the gas channel groove 55 may be tapered so that the width becomes wider toward the end.

In the fuel cell gas supply diffusion layer 42a according to Embodiment 2, as shown in FIG. 8, the straight portions 55a have the same length and the corner portions 55b have the same shape. As described above, when a plurality of rectangular regions (rectangular regions) R circumscribed by each of the plurality of gas flow channel grooves 55 are defined in plan view, one gas A first rectangular region R1 circumscribed by the channel groove 55 and a second rectangular region R2 circumscribed by the gas channel groove 55 adjacent to one gas channel groove overlap along the contacting regions. (See FIG. 10.) Moreover, an overlapping region R3 where the first rectangular region R1 and the second rectangular region R2 overlap exists at any of the depth positions D1, D2, and D3 of the plurality of gas channel grooves 55. (See FIGS. 11 and 12).

When the fuel cell stack 20 is operated, protons (H ⁺ ) are generated at the fuel electrode into which the anode gas (hydrogen gas) is introduced. The protons diffuse through the membrane electrode assembly 81, move to the oxygen electrode side, and react with oxygen to produce water. The produced water is discharged from the oxygen electrode side. At this time, in the cathode gas separator 24a having the fuel cell gas supply diffusion layer 42a according to Embodiment 2, the air that has flowed in from the cathode gas inlet 62A passes through the inflow passage 57 and the gas inflow side groove 51 to the gas flow path. It flows into the groove 55 for use. Part of the air that has flowed into the gas inflow side groove 51 enters the gas channel groove 55 and enters the porous body 40 from the gas channel groove 55, and the other part enters from the end face of the porous body 40. It directly enters the porous body 40 and diffuses inside the porous body 40 .

The air diffuses in the thickness direction while diffusing in the planar direction within the porous body 40, is supplied to the membrane electrode assembly 81 provided in contact with the porous body 40, and contributes to the power generation reaction. Gases not used for power generation (unused oxygen gas and nitrogen gas) and water (steam or condensed water) generated during power generation flow out through the porous body 40, the gas channel groove 55, and the gas outlet side groove 52. It flows out to passage 58 . The oxygen gas, nitrogen gas and water that have flowed out to the outflow passage 58 are finally discharged from the outflow passage 58 through the cathode gas outlet 62B and the cathode gas outlet 72B. At this time, due to the structure of the fuel cell gas supply diffusion layer 42a, not all of the water is discharged and part of it remains in the porous body 40. FIG.

In addition to the effects of the fuel cell according to Embodiment 1, the fuel cell according to Embodiment 2 has the following effects.

According to the fuel cell according to the second embodiment, since the fuel cell gas supply diffusion layer 42a has a plurality of gas channel grooves 55 through which the cathode gas flows, the movement resistance of the cathode gas is reduced compared to the conventional art. , a larger amount of cathode gas than before can be supplied to the membrane electrode assembly 81 .

Further, according to the fuel cell according to the second embodiment, since the plurality of gas channel grooves 55 are formed on one surface of the fuel cell gas supply diffusion layer 42a, the fuel cell gas supply diffusion layer Cathode gas is always supplied to the membrane electrode assembly 81 disposed on the other surface of the porous body 42a through the porous body 40, so that a plurality of gas flow paths extend from one surface of the porous body 40 to the other. Cathode gas can be more uniformly supplied to the membrane electrode assembly 81 than in the case of openings over the entire surface.
Further, according to the fuel cell according to the second embodiment, the plurality of gas channel grooves 55 are formed in a zigzag pattern from the cathode gas inflow side to the outflow side on one surface of the fuel cell gas supply diffusion layer 42a. Since it is formed in a shape or a wave shape, not only the gas flow in the gas flow channel groove 55 but also the gas flow (underflow gas flow) that short-circuits the upstream channel and the downstream channel is formed. , the supply path of the cathode gas supplied to the porous body 40 is widely dispersed in the plane, and a plurality of gas flow path grooves are formed linearly from the gas inflow side to the outflow side. Cathode gas can be more uniformly supplied to the membrane electrode assembly 81 than in the case.

Further, according to the fuel cell according to the second embodiment, in the first rectangular region R1 circumscribed by one gas flow channel groove 55A of the plurality of gas flow channel grooves 55, the one gas flow channel groove 55A Part of the cathode gas flowing through the grooves 55A enters the porous body 40 to form a so-called underflow region in the first rectangular region R1. Part of the cathode gas flowing through the groove 55B enters the porous body 40 to form a so-called underflow region in the second rectangular region R2, and the first rectangular region R1 and the second rectangular region R2 are in contact with each other. 10 and 11), the supply path of the cathode gas supplied to the porous body 40 is dispersed in the plane without gaps. It can be more uniformly supplied to the joined body 81 .

Further, according to the fuel cell according to the second embodiment, the overlapping region R3 where the first rectangular region R1 and the second rectangular region R2 overlap is located at any depth position D1, D2, . 11 and 12), the supply path of the cathode gas supplied to the porous body 40 is also present at any depth position D1, D2, or D3 of the gas flow channel groove 55. The cathode gas can be more uniformly supplied to the membrane electrode assembly 81 because the cathode gas is dispersed inside the membrane electrode assembly 81 without gaps.

As a result, the fuel cell according to the second embodiment can uniformly supply a larger amount of cathode gas to the membrane electrode assembly 81 than in the conventional case, so that the fuel cell can achieve higher power generation efficiency than in the conventional case. becomes.

Further, in the fuel cell according to the second embodiment, since the fuel cell gas supply diffusion layer 42a has the above characteristics, the cathode gas (oxygen gas, nitrogen gas) not used for power generation is Since it becomes possible to efficiently discharge outside the gas channel groove 55 through the body 40 and the gas channel groove 55, the cathode not used for power generation is pushed out by the underflow gas flow in the underflow region. Gases (oxygen gas, nitrogen gas) can be efficiently discharged out of the gas channel groove 55, so that the movement resistance of the cathode gas can be kept lower than before, and the reaction gas concentration can be kept high. As a result, the fuel cell can achieve a higher power generation efficiency than the conventional one.

Further, in the fuel cell according to the second embodiment, since the fuel cell gas supply diffusion layer 42a has the characteristics as described above, water vapor or condensed water generated in the membrane electrode assembly 81 during power generation is transferred to the porous body. 40 and the gas flow channel groove 55 to the outside of the gas flow channel groove 55, and in the underflow region, water vapor or condensed water is pushed out by the underflow gas flow. Since it becomes possible to efficiently discharge the fuel to the outside of the use groove 55, the fuel cell has better drainage than the conventional one.

Further, according to the fuel cell according to the second embodiment, in the fuel cell gas supply diffusion layer 42a, the width L1 of the overlapping region R3 and the width L of the rectangular region are such that "L1≧0.1×L". Since the relationship is satisfied, the planar area ratio of the overlapping region R3 in the fuel cell gas supply diffusion layer 42a can be increased, and the cathode gas can be supplied to the membrane electrode assembly 81 more uniformly.

[Embodiment 3]
FIG. 14 is a plan view of the cathode gas separator 24b in Embodiment 3 as viewed from the metal plate 30 side. In FIG. 14, reference character R4 denotes a "divided overlapping area", which will be described later.
A fuel cell according to Embodiment 3 (wholly not shown) has basically the same configuration as that of the fuel cell according to Embodiment 2, except that the cathode gas separator has grooves for gas flow paths. It differs from the fuel cell according to the second embodiment in that gas pressure equalizing grooves are formed in addition to the above.
That is, in the cathode gas separator according to Embodiment 3, as shown in FIG. A single gas pressure equalizing groove 56 is formed over the entire width direction perpendicular to the direction toward the outflow side. Further, when the overlapping region divided by the gas pressure equalizing groove 56 is defined as a “divided overlapping region R4”, the divided overlapping region R4 exists at any depth position of the plurality of gas flow channel grooves 55. do.
A plurality of gas pressure equalizing grooves 56 may be formed.

In addition to the effects of the fuel cell according to Embodiment 2, the fuel cell according to Embodiment 3 has the following effects.
That is, according to the fuel cell according to the third embodiment, due to the action of the gas pressure equalizing grooves 56 in the fuel cell gas supply diffusion layer 42b, the width direction perpendicular to the direction from the cathode gas inflow side to the outflow side The supply amount of the cathode gas can be made uniform throughout. In addition, since the divided overlap region R4 exists at any depth position of the plurality of gas flow channel grooves 55, the supply paths of the cathode gas supplied to the porous body 40 are dispersed without any gaps. can be more uniformly supplied to the membrane electrode assembly 81 .

In the fuel cell gas supply diffusion layer 42b according to Embodiment 3, the depth of the gas channel groove 55 and the depth of the gas pressure equalization groove 56 are made equal. Therefore, the gas flow channel groove 55 and the gas pressure equalizing groove 56 can be formed in the same manufacturing process using a mold with a simple structure. It also has the effect of suppressing an increase in manufacturing cost due to the formation.

[Embodiment 4]
FIG. 15 is a plan view of the cathode gas separator 24c in Embodiment 4 as viewed from the metal plate 30 side.
A fuel cell according to Embodiment 4 (wholly not shown) has basically the same configuration as that of the fuel cell according to Embodiment 2, but the configuration of the gas channel grooves 55 is the same as that of Embodiment 2. It is different from the case of the fuel cell according to
That is, in the fuel cell gas supply diffusion layer 42c according to Embodiment 4, as shown in FIG. The width W2 of the outflow side end of the road groove 55 is configured to satisfy the relationship of "W2<W1".
In Embodiment 4, the width W of the gas channel groove 55 is gradually narrowed from the gas inflow side to the gas outflow side.

One or a plurality of gas pressure equalizing grooves may be formed in the fuel cell gas supply diffusion layer 42c over the entire width direction orthogonal to the direction from the inflow side to the outflow side of the cathode gas.

In addition to the effects of the fuel cell according to Embodiment 2, the fuel cell according to Embodiment 4 has the following effects.
That is, according to the fuel cell gas supply diffusion layer 42c according to the fourth embodiment, since the linear velocity of the gas flow in the gas channel groove 55 is higher on the outflow end side, The undercurrent ratio of the gas in the gas flow increases, and a larger amount of the cathode gas can be evenly fed into the porous body 40, and even in the area on the outflow side, it is possible to suppress the decrease in the cathode gas concentration in the so-called underflow area. can.
In addition, water vapor or condensed water, which is generated as a reaction product and increases downstream, can be effectively discharged.

[Embodiment 5]
FIG. 16 is a plan view of the cathode gas separator 24d in Embodiment 5 as viewed from the metal plate 30 side.
17 is a cross-sectional view along A5-A5 in FIG. 16. FIG. In FIG. 17, in order to show the positional relationship between the cathode gas separator 24d and the membrane electrode assembly 81, the cathode gas separator 24d with the membrane electrode assembly 81 joined is shown. Also, the cross-sectional structure of the membrane electrode assembly 81 is omitted.
FIG. 18 is a diagram for explaining the flow of cathode gas. FIG. 18(a) is an enlarged plan view of the portion B of FIG. 16, and FIG. 18(b) is a cross-sectional view taken along line CC of FIG. 18(a).

A plurality of isolated holes indicated by reference numeral 155 are formed in the cathode gas separator 24d. is omitted. Also, in FIGS. 16 to 18, the reference numerals (551) to (553) in parentheses may be indicated after the reference numeral 155 indicating the isolated holes. is shown for convenience of explanation and does not show an isolated hole at a specific location. In FIG. 18, the arrows indicate the flow of the cathode gas, the thick arrows indicate the overall flow of the cathode gas from the inflow side to the outflow side, and the thin arrows indicate the isolated hole 155 to the porous body 40 (gas flow). The flow of the cathode gas (underflow gas flow) pushed out into the diffuser) is shown.

The fuel cell according to Embodiment 5 (wholly not shown) has basically the same configuration as the fuel cell 1 according to Embodiment 1, except that the configuration of the cathode gas separator is the same as that of Embodiment 1. It is different from the case of the fuel cell 1 according to .
The fuel cell according to Embodiment 5 (not shown in its entirety) will be described below, focusing on differences from the fuel cell 1 according to Embodiment 1. FIG. Also, the description of the matters described in the first embodiment will be omitted as appropriate.

The cathode gas separator 24d has a structure in which a fuel cell gas supply diffusion layer 42d is formed on one surface of a metal plate 30, as shown in FIGS.

As shown in FIGS. 16 and 17, the cathode gas separator 24d is placed in the center of one surface of a rectangular metal plate 30 as a substrate, from upstream to downstream, cathode gas (fuel cell gas). A gas supply diffusion layer 42d for a fuel cell is formed through which the gas flows to supply and diffuse the cathode gas. The fuel cell gas supply diffusion layer 42d is a fuel cell gas supply diffusion layer through which the cathode gas flows from the upstream side to the downstream side during use, and is a porous body that permeates and diffuses the cathode gas and has electrical conductivity. has 40. The fuel cell gas supply diffusion layer 42 d also has a plurality of isolated holes 155 distributed on one surface of the porous body 40 . Each of the isolated holes 155 is isolated from each other and formed in the fuel cell gas supply diffusion layer 42d. Consists of recesses. Further, the fuel cell gas supply diffusion layer 42d has a gas inflow side groove 51 positioned at a corner on the inflow side of one surface and a gas outflow side groove 52 positioned at a corner on the outflow side of one surface (Fig. 16). The fuel cell gas supply diffusion layer 42d may include grooves for gas pressure equalization formed over the entire width direction orthogonal to the direction from the inflow side of the cathode gas to the outflow side, or the A bypass groove extending from the inflow side or the outflow side toward the central portion may be provided.

Hereinafter, the flow direction from the upstream side to the downstream side (the direction from the side where the cathode gas inlet 62A is provided to the side where the cathode gas outlet 62B is provided; in FIG. ) is defined as the Y direction, and the width direction perpendicular to the Y direction in plan view (the direction indicated by the arrow X in FIG. 16) is defined as the X direction.

The gas inflow side groove 51 has a thin rectangular groove portion (stepped portion) extending fully in the width direction at the inflow side corner of the fuel cell gas supply diffusion layer 42d when viewed in plan. Further, the gas inflow side groove 51 may have a plurality of branched groove portions (branched stepped portions) branching from the rectangular grooved portion (stepped portion) to the outflow side in the Y direction so as to correspond to the isolated holes 155 . . For example, FIG. 16 depicts a plurality of branched groove portions (branched stepped portions) branching to the Y-direction outflow side in a shape obtained by cutting out a circular isolated hole 155 from a rectangular grooved portion (stepped portion). The gas inflow side groove 51 is formed with a predetermined depth.

The gas outflow side groove 52 has a thin rectangular groove portion (step portion) extending in the width direction at the outflow side corner of the fuel cell gas supply diffusion layer 42d in a plan view. Further, the gas outflow side groove 52 may have a plurality of branched groove portions (branched stepped portions) branching from the rectangular grooved portion (stepped portion) to the inflow side in the Y direction so as to correspond to the isolated holes 155 . . For example, FIG. 16 depicts a plurality of branched groove portions (branched stepped portions) branching to the inflow side in the Y direction in a shape obtained by cutting out a circular isolated hole 155 from a rectangular grooved portion (stepped portion). The gas outflow side groove 52 is formed with the same depth as the gas inflow side groove 51 .

In the fuel cell gas supply diffusion layer 42d according to Embodiment 5, the isolated holes 155 are distributed over a desired range on one surface of the porous body 40 . Each isolated hole 155 preferably has a shape with a predetermined regularity, and the position of the center of gravity of each isolated hole 155 is arranged with a predetermined regularity on one surface of the fuel cell gas supply diffusion layer 42d. is preferred. Here, the desired range is defined as a range (in FIG. 16, This is the range surrounded by the chain double-dashed line indicated by the symbol Ra). The desired range should cover 60% or more, preferably 70% or more, more preferably 80% or more of the surface area of one side of the fuel cell gas supply diffusion layer 42d. The desired range may be distributed over the entire surface of one surface of the fuel cell gas supply diffusion layer 42d. In addition, the isolated holes 155 being dispersedly arranged does not only mean that they are arranged side by side in the X direction and the Y direction at equal pitches. It means that it is present and arranged.

The isolated hole 155 has a desired range of area (a range surrounded by a closed curve connecting the center of gravity of the outer isolated hole 155 among the isolated holes 155 formed on one surface of the fuel cell gas supply diffusion layer 42d). The area of the planar projection range) is S1, and the total area of the plurality of isolated holes 155 (the total area of the planar projected areas of the isolated holes 155 for all the isolated holes that constitute the plurality of isolated holes 155). ) is set to S2, it is preferable that the elements are arranged so as to satisfy the relationship “0.9×S1≧S2≧0.1×S1”.

The isolated holes 155 may all have the same shape and size, or may have the same shape but different sizes. It is preferable that the isolated holes 155 are arranged with regularity at least within a desired range.

The shape of the bottom of the isolated hole 155 may be flat parallel to the membrane electrode assembly 81 or the electrolyte membrane 82, or the depth may vary depending on the location.

Each isolated hole 155 may have a shape with a varying width, such as a circular shape, an elliptical shape, a rhombic shape, or a triangular shape in plan view. Each isolated hole 155 may be formed to the same depth as the gas inlet side groove 51 and the gas outlet side groove 52 and to have a constant depth. The porous body 40 (gas diffusion portion) is exposed on the inner surface of each isolated hole 155 .
In this way, if the plurality of isolated holes 155 are configured such that the widths of the holes 155 are changed in a circle, an ellipse, a rhombus, a triangle, etc., it is possible to spread the cathode gas two-dimensionally and supply it.

As the isolated hole 155, an isolated hole having a planar shape (for example, a rectangle) with a constant width may be used. With such a configuration, when the planar shape of the fuel cell gas supply diffusion layer 42d (porous body 40) is rectangular, the isolated hole 155 can be replaced by the fuel cell gas supply diffusion layer 42d (porous body 40). ) can be easily arranged over the entire surface of one side.
Also, as the isolated hole 155, an isolated hole that is curved in the middle may be used. Examples of the shape of the isolated hole 155 that is curved in the middle include L-shape, U-shape, C-shape, arc shape, and the like.
Furthermore, the isolated hole 155 may be formed such that the planar area of the isolated hole 155 gradually decreases toward the downstream side. With such a configuration, the flow rate of the cathode gas decreases toward the downstream side, so that the concentration of the cathode gas becomes more uniform between the upstream side and the downstream side, and the cathode gas becomes more efficient. can spread well.

The isolated hole 155 has a regular positional relationship between one isolated hole 155 (551) of the plurality of isolated holes 155 and the isolated holes 155 (552, 553) adjacent to the downstream side of the one isolated hole 155 (551). It is preferable that they are arranged in such a way that they are flexible. As shown in FIG. 16, the isolated hole 155 has a distance along the X direction from one isolated hole 551 out of the isolated holes 155 positioned downstream from one isolated hole 551 out of the plurality of isolated holes 155 . The shortest isolated hole 155 (that is, the isolated hole having the smallest absolute value of the X-direction component of the vector connecting the center of gravity of the isolated hole 551 and the center of gravity of the adjacent isolated hole 155 (including the case where the absolute value is zero, of course) 155 is a first adjacent isolated hole 552, and the isolated hole 155 having the second shortest distance along the X direction from one isolated hole 551 (that is, the center of gravity of the isolated hole 551 and the center of gravity of the adjacent isolated hole 155 are connected). When the isolated hole 155 having the second smallest absolute value of the X-direction component of the vector is defined as the second adjacent isolated hole 553, the distance between the one isolated hole 551 and the first adjacent isolated hole 552 is The first distance L1a, which is the shortest distance between the opening of the isolated hole 551 and the opening of the first adjacent isolated hole 552, and the distance between the isolated hole 551 and the second isolated hole 553. As shown in FIG. 16, the second distance L2a, which is the shortest distance between the opening of one isolated hole 551 and the opening of the second adjacent isolated hole 553, satisfies the relationship of "L2a≦L1a". In other words, in one isolated hole 551, the first adjacent isolated holes 552 aligned in the Y direction (the distance along the X direction is the shortest) and the first adjacent isolated holes 552 located in adjacent rows (rows on both sides). The two adjacent isolated holes 553 are close to each other, but the distance the cathode gas passes through the porous body 40 (gas diffusion portion) when moving from one isolated hole 551 to the second isolated hole 553 is one. It is set to be shorter than the distance through the porous body 40 (gas diffusion portion) when moving from the isolated hole 551 to the first adjacent isolated hole 552. In this way, the gas extruded from one isolated hole 551 is made shorter. The cathode gas flows more easily toward the second isolated hole 553 than to the first isolated hole 552. Therefore, the cathode gas pushed out from one isolated hole 551 flows more easily toward the first isolated hole 552 than the first isolated hole 552. , the cathode gas can be diffused more widely by moving more towards the second adjacent isolated holes 553. Therefore, the cathode gas can be uniformly diffused over the entire porous body 40. FIG.

Further, the first interval L1a and the second interval L2a may further satisfy the relationship of "L1a<2×L2a" as shown in FIG. That is, the interval between the one isolated hole 551 and the second adjacent isolated hole 553 is the same as the interval between the second adjacent isolated hole 553 and the first adjacent isolated hole 552, and the cathode gas is directly discharged from the one isolated hole 551. The distance that passes through the porous body 40 (gas diffusion portion) when moving to the first proximal isolated hole 552 is moved from one isolated hole 551 to the first proximal isolated hole 552 via the second proximal isolated hole 553. The distance is set shorter than the distance that passes through the porous body 40 (gas diffusion portion). In this way, the distance (first interval L1a) that the cathode gas passes through the porous body 40 (gas diffusion portion) when moving directly from one isolated hole 551 to the first adjacent isolated hole 552 is Shorter than the distance (2×second interval L2a) that passes through the porous body 40 (gas diffusion portion) when moving from one isolated hole 551 to the first proximal isolated hole 552 via the second proximal isolated hole 553 Become. Therefore, the flow of the cathode gas directly from one isolated hole 551 to the first adjacent isolated hole 552 does not become extremely small, and the cathode gas can be diffused over the entire porous body 40 in a well-balanced manner.

When the relationship of "L2a≦L1a" and the relationship of "L1a<2×L2a" are satisfied, the values of the pitch in the X direction and the pitch in the Y direction between the isolated holes are ≦L1a” and the relationship of “L1a<2×L2a” may be appropriately set.

In the fuel cell gas supply diffusion layer 42d in the fuel cell according to Embodiment 5, the desired range of area The area S1 of the planar projected range of the range surrounded by the closed curve connecting the centroid positions of the isolated holes 155 and the total area S2 of the plurality of isolated holes are "0.9×S1≧S2≧0.1×S1". The reason why it is preferable to arrange so as to satisfy the relationship is as follows.
That is, when the above S2 is 10% or more of the above S1, the movement resistance when the cathode gas flows in a desired range can be sufficiently reduced, so that the membrane electrode assembly 81 is provided with a larger amount of gas than before. of cathode gas can be supplied. In addition, when S2 is 90% or less of S1, a minimum region in which the cathode gas flows underflow while diffusing within the desired range can be ensured, so that the cathode gas can be easily diffused uniformly within the desired range. It is from. From the viewpoint of supplying a larger amount of cathode gas, the area S1 of the porous body 40 (gas diffusion portion) and the total area S2 of the plurality of isolated holes 155 satisfy the relation of "S2≧0.2×S1". It is more preferable to satisfy the relationship, and it is even more preferable to satisfy the relationship "S2≧0.3×S1". Moreover, from the viewpoint of diffusing within a desired range, it is more preferable to satisfy the relationship of "0.8×S1≧S2", and it is even more preferable to satisfy the relationship of "0.7×S1≧S2". .

The porous body 40 (gas diffusion portion) has electrical conductivity and fine voids are formed therein. The porous body 40 (gas diffusion portion) has a substantially rectangular shape in a plan view. The porous body 40 (gas diffusion portion) is formed with a porosity suitable for underflowing gas or liquid through the voids. Details will be described later.

In the description of the fuel cell according to Embodiment 5, the term "underflow" refers to the flow that is pushed out into the porous body 40 from the gas inflow side groove 51, the isolated holes 155, the gas pressure equalization groove, the bypass groove, and the like. This is the flow of the cathode gas (backflow gas).
As shown in FIG. 16, the isolated holes 155 may be aligned along the Y direction from the bottom to the top of the page of FIG. 16, or may be aligned along other directions.

Furthermore, the cathode gas separator 24d will be described in detail.
As a rough guideline, the porosity of the porous body 40 in the fuel cell gas supply diffusion layer 42d is about 50 to 85%.
Since the porosity of the porous body 40 is configured as described above, the cathode gas, water vapor, and condensed water flow between the isolated hole 155 and the porous body 40 through the inner surface of the isolated hole 155. As a result, a large amount of cathode gas can be uniformly supplied to the membrane electrode assembly 81, and cathode gas not used during power generation, water vapor and condensed water generated during power generation can be efficiently discharged out of the isolated hole 155. As a result, in the fuel cell gas supply diffusion layer 42d, the isolated hole 155 is a gas permeable layer in which a large number of fine gas flow holes are opened in the gas impermeable layer made of metal, ceramics, resin, etc. on the inner surface of the isolated hole 155. There is no need to form something like a filter, and the porous body 40 is configured to be exposed on the inner surface.

A plurality of isolated holes 155 consisting of gaps are provided on the surface of the fuel cell gas supply diffusion layer 42d facing the metal plate 30, and the gaps between the plurality of isolated holes 155 and the metal plate 30 have a plurality of holes. of gas flow paths are formed. A plurality of isolated holes 155 are formed in the arrangement as described above. Each isolated hole 155 reduces the movement resistance of the cathode gas that has flowed into the porous body 40 (gas diffusion portion) and spreads it, allowing it to flow out again into the porous body 40 (gas diffusion portion). Diffusion by subsoil. The number and structure of isolated holes 155 are not limited to those shown.

When the fuel cell gas supply diffusion layer 42d in Embodiment 5 is used in a fuel cell for transportation equipment, the width of the fuel cell gas supply diffusion layer 42d varies depending on the type and size of the transportation equipment. is, for example, about 30 mm to 300 mm. The width of the isolated hole 155 is, for example, about 0.3 mm to 2 mm. The thickness of the porous body 40 is, for example, about 150 to 400 μm, the depth of the isolated hole 155 is, for example, about 100 to 300 μm, and the distance between the bottom of the isolated hole 155 and the other surface of the porous body 40 (ceiling thickness) is, for example, about 100 to 300 μm. When the fuel cell gas supply diffusion layer 42d of Embodiment 5 is used in fuel cells for applications other than transportation equipment (for example, for stationary use), the sizes are not limited to those described above, and the required performance and the like can be used. A suitable size can be used accordingly.

When the fuel cell stack according to Embodiment 5 is operated, in the cathode gas separator 24d having the fuel cell gas supply diffusion layer 42d having the structure described above, the air flowing in from the cathode gas inlet 62A flows through the inflow passage 57. And the air that enters the porous body 40 (gas diffusion portion) from the gas inflow side groove 51 and flows underflow passes through the isolated hole 155, thereby reducing the distance that it passes through the porous body 40, which has a large movement resistance. It moves between the holes 155 and goes to the outflow side. The air that has flowed into the isolated hole 155 spreads inside the isolated hole 155, is pushed out again from the inner surface of the isolated hole 155 to the porous body 40 (gas diffusion portion), and is forced to underflow and diffuse in various directions.

16 and 18(a), the cathode gas (air) passing between the isolated holes 155 and moving toward the outflow side will be explained in more detail. Since it is smaller than the porous body 40 (gas diffusion portion), the air tends to pass through the isolated holes 155 rather than through the porous body 40 (gas diffusion portion). Therefore, the air pushed out in the planar direction from one isolated hole 551 to the porous body 40 (gas diffusion portion) flows underflow toward the first proximal isolated hole 552 or the second proximal isolated hole 553 adjacent to the downstream side. do. In particular, when the first interval L1a and the second interval L2a satisfy the relationship of "L1a≦L2a", the porous body 40 (gas diffusion portion) from one isolated hole 551 to the second adjacent isolated hole 553 is The passing distance (second interval L2a) is the same as or shorter than the distance (first interval L1a) passing through the porous body 40 (gas diffusion portion) to the first isolated hole 552, and the distance from the one isolated hole 551 Most of the pushed-out cathode gas is shifted in the X direction and underflows toward the second proximal isolated hole 553 . The cathode gas that has flowed into the second proximal isolated hole 553 is pushed out to the porous body 40 (gas diffusion portion) again, and similarly underflows toward the isolated hole 155 adjacent to the second proximal isolated hole 553 . By such repetition, the air flows across the isolated holes 155 toward the outflow side.

Further, when the first interval L1a and the second interval L2a further satisfy the relationship of “L1a<2×L2a”, the porous body 40 (gas The distance (first interval L1a) passing through the gas diffusion portion) passes through the porous body 40 (gas diffusion portion) from one isolated hole 551 to the first proximal isolated hole 552 via the second proximal isolated hole 553. The distance becomes shorter than the distance (2×second interval L2a), and part of the cathode gas underflows along a route directly from one isolated hole 551 to first adjacent isolated hole 552 .

Further, as shown in FIG. 18(b), the cathode gas diffuses in the thickness direction while diffusing in the planar direction in the porous body 40 (gas diffusion portion). is supplied to the membrane electrode assembly 81 provided in contact with and contributes to the power generation reaction. Gases not used for power generation (unused oxygen gas and nitrogen gas) and water (steam or condensed water) generated during power generation pass through the porous body 40 (gas diffusion portion), the isolated hole 155, and the gas outlet groove 52. and flows out to the outflow passage 58 . The oxygen gas, nitrogen gas and water that have flowed out to the outflow passage 58 are finally discharged from the outflow passage 58 through the cathode gas outlet 62B and the cathode gas outlet 72B. At this time, due to the structure of the fuel cell gas supply diffusion layer 42d, not all of the water is discharged, and part of it remains in the porous body 40 (gas diffusion portion).

In addition to the effects of the fuel cell according to Embodiment 1, the fuel cell according to Embodiment 5 has the following effects.

According to the fuel cell according to the fifth embodiment, since the plurality of isolated holes 155 are arranged on one surface of the fuel cell gas supply diffusion layer 42d, the cathode gas can flow into the fuel cell gas supply diffusion layer 42d. When flowing through the isolated hole 155 , the movement resistance is smaller and the flow is smoother than when flowing through the porous body 40 (gas diffusion portion).

Further, according to the fuel cell according to the fifth embodiment, since the plurality of isolated holes 155 are formed in one surface of the fuel cell gas supply diffusion layer 42d in the fuel cell gas supply diffusion layer 42d, the fuel Since the supply of the cathode gas to the membrane electrode assembly 81 disposed on the other surface of the battery gas supply diffusion layer 42d is always performed through the porous body 40, a plurality of gas flow paths are used for the fuel cell gas supply. Cathode gas can be more uniformly supplied to the membrane electrode assembly 81 than when the diffusion layer 42d is formed from one surface to the other surface.

In addition, since the periphery of the isolated hole 155 is surrounded by the porous body 40, the cathode gas always advances through the porous body 40 to the isolated hole 155 on the downstream side. The cathode gas can be more uniformly diffused over the entire porous body 40 than in the case where the gas flow path 42d is formed to extend from the inflow side to the outflow side.

As a result, the fuel cell according to Embodiment 5 can uniformly supply a large amount of cathode gas to the membrane electrode assembly 81, so that the power generation efficiency of the fuel cell can be increased.

Further, in the fuel cell according to the fifth embodiment, since the fuel cell gas supply diffusion layer 42d has the above characteristics, the cathode gas (oxygen gas, nitrogen gas) not used for power generation is Since it is possible to efficiently discharge the gas to the outside of the fuel cell gas supply diffusion layer 42d through the body 40 (gas diffusion portion) and the isolated hole 155, the movement resistance of the cathode gas is lower than before, and the reaction gas concentration is reduced. As a result, the power generation efficiency of the fuel cell can be made higher than that of the conventional fuel cell.

In the fuel cell according to Embodiment 5, since the fuel cell gas supply diffusion layer 42d has the characteristics described above, the water vapor or condensed water generated in the membrane electrode assembly 81 during power generation is transferred to the porous body. 40 (gas diffusion portion) and the isolated hole 155, the gas can be efficiently discharged to the outside of the fuel cell gas supply diffusion layer 42d.

In the fuel cell according to Embodiment 5, since the fuel cell gas supply diffusion layer 42d has the characteristics described above, water (water vapor or condensed water) generated in the membrane electrode assembly during power generation is transferred to the porous body. 40 and the isolated hole 155, it can be efficiently discharged to the outside of the isolated hole 155.例文帳に追加Further, in the underflow region, the water can be efficiently discharged outside the isolated holes 155 by being pushed out by the underflow gas flow.

Further, in the fuel cell according to the fifth embodiment, since the fuel cell gas supply diffusion layer 42d has the above characteristics, the cathode gas not used for power generation is And, since it becomes possible to collect efficiently through the isolated hole 155, the fuel cell can achieve a higher power generation efficiency than the conventional fuel cell. Furthermore, since the fuel cell gas supply diffusion layer 42d has the above-mentioned characteristics, water vapor or condensed water generated in the membrane electrode assembly 81 during power generation can be efficiently discharged through the porous body 40 and the isolated holes 155. Since it can be collected well, the fuel cell has better drainage than conventional fuel cells.

In the fuel cell according to Embodiment 5, since the fuel cell gas supply diffusion layer 42d has the characteristics described above, the cathode gas not used for power generation is efficiently discharged through the porous body 40 and the isolated holes 155. As a result, the fuel cell can lower the movement resistance of the cathode gas and further increase the power generation efficiency of the fuel cell.

In the fuel cell according to Embodiment 5, the cathode gas separator 24d is a fuel cell separator including a metal plate 30 and a fuel cell gas supply diffusion layer 42d provided on one surface of the metal plate 30. The fuel cell gas supply diffusion layer 42d is arranged with respect to the metal plate 30 so that the plurality of isolated holes 155 are positioned on the metal plate 30 side, and the isolated holes 155 and the metal plate 30 provide gas Since the flow path is formed, the power generation efficiency of the fuel cell can be made higher than that of the conventional fuel cell, and furthermore, the fuel cell has superior drainage performance than that of the conventional fuel cell.

Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments. It is possible to implement in various aspects without departing from the scope of the invention.

Reference Signs List 1 fuel cell 20 fuel cell stack 24, 24a, 24b, 24c, 24d cathode gas separator 26 anode gas separator 27A, 27B collector plate 28A, 28B insulation sheet DESCRIPTION OF SYMBOLS 30... Metal plate 32... Dense frame 33... Gasket 40... Porous body 42, 42a, 42b, 42c, 42d... Gas supply diffusion layer for fuel cell 51... Gas inflow side groove 52... Gas outflow side groove, 55, 55A, 55B... Groove for gas flow path 55a... Straight part 55b... Corner part 56... Groove for equalizing gas pressure 57... Inflow passage 58... Outflow passage 61A... Anode gas inlet 61B... Anode gas outlet 62A Cathode gas inlet 62B Cathode gas outlet 63A Refrigerant inlet 63B Refrigerant outlet 71A Anode gas supply port 71B Anode gas outlet 72A Cathode gas supply Port 72B Cathode gas outlet 73A Coolant supply port 73B Coolant outlet 75, 76 End plate 81 Membrane electrode assembly 82 Electrolyte membrane 83 Microporous layer 85 Catalyst layer , 88... Gas diffusion layer, 90... Flow path defining plate, 91... Spacer, 92... First convex portion, 93... First concave portion, 94... Second convex portion, 95... Second concave portion, 155... Isolated hole, 551 One isolated hole 552 First adjacent isolated hole 553 Second adjacent isolated hole L Width of overlapping region L2 Arrangement pitch L1a First interval L2a Second interval R Rectangular area , R1 .

Claims (11)

A fuel cell in which a cathode gas separator, a membrane electrode assembly, a gas diffusion layer, and an anode gas separator are laminated,
The cathode gas separator has a metal plate and a fuel cell gas supply diffusion layer having a conductive porous body,
The anode gas separator has a first projection that is arranged on one surface and defines a flow path for the anode gas, and a first projection that is arranged on the other surface opposite to the one surface and defines a flow path for the coolant. Having a flow path defining plate having two convex portions,
The fuel cell, wherein the membrane electrode assembly is disposed between the fuel cell gas supply diffusion layer and the gas diffusion layer. The flow path defining plate is made of a metal material,
On the back side of the first convex portion, there is a first concave portion that serves as a flow path for the coolant,
2. The fuel cell according to claim 1, wherein a second concave portion serving as a channel for the anode gas is present on the back side of the second convex portion. 3. A microporous layer is disposed between at least one of the cathode gas separator and the membrane electrode assembly and between the gas diffusion layer and the membrane electrode assembly. 3. The fuel cell according to 1 or 2. 4. The fuel cell according to any one of claims 1 to 3, wherein said fuel cell gas supply diffusion layer further has a plurality of gas channel grooves for flowing a cathode gas. the plurality of gas channel grooves are formed in parallel on one surface of the fuel cell gas supply diffusion layer and each formed in a zigzag or wavy shape from the cathode gas inflow side to the outflow side,
A first rectangular region R1 circumscribed by one gas flow channel groove among a plurality of rectangular regions R circumscribed by each gas flow channel groove of the plurality of gas flow channel grooves in plan view; , a second rectangular region R2 circumscribed by the gas flow channel groove adjacent to the one gas flow channel groove overlaps along the contact region, and the first rectangular region R1 and the second rectangular region R2 5. The overlapping region R3 overlapping with the region R2 is present at any depth position of the plurality of gas flow channel grooves regardless of the cross-sectional shape of the plurality of gas flow channel grooves. A fuel cell as described. In the fuel cell gas supply diffusion layer, one or a plurality of gases are distributed over the entire width direction orthogonal to the direction from the inflow side to the outflow side of the cathode gas so as to intersect with the plurality of gas flow channel grooves. A groove for pressure equalization is formed,
When the overlapping region divided by the gas pressure equalizing grooves is defined as a “divided overlapping region R4”, the divided overlapping region R4 is defined as the plurality of 6. The fuel cell according to claim 5, wherein the gas channel grooves exist at any depth position. A width W1 of the inflow side end of the gas flow path groove and a width W2 of the outflow side end of the gas flow path groove satisfy a relationship of "W2<W1". Or the fuel cell according to 6. The fuel cell gas supply diffusion layer in the cathode gas separator further has a plurality of isolated holes dispersedly arranged on one surface of the fuel cell gas supply diffusion layer,
Each of the isolated holes is isolated from each other and formed in the fuel cell gas supply diffusion layer, is surrounded by the porous body except for the opening, and comprises a recess having a bottom of the porous body. 4. The fuel cell according to any one of claims 1 to 3. The fuel cell according to any one of claims 1 to 8 is laminated,
A fuel cell stack, wherein the metal plate and the flow path defining plate of the adjacent fuel cells are in contact with each other at the top of the second projection. A fuel cell in which a cathode gas separator, a membrane electrode assembly, a gas diffusion layer, and an anode gas separator are laminated,
The cathode gas separator has a first metal plate having a flat portion, and a fuel cell gas supply diffusion layer having a conductive porous body,
The anode gas separator has a second metal plate,
The second metal plate has a first protrusion on one surface and a second protrusion on the other surface opposite to the one surface,
The first convex portion forms a first concave portion that serves as a coolant flow path on the other surface,
the second protrusion forms a second recess that serves as an anode gas flow path on the one surface;
The membrane electrode assembly is disposed between the fuel cell gas supply diffusion layer and the gas diffusion layer,
The fuel cell gas supply diffusion layer is disposed between the first metal plate and the membrane electrode assembly,
the gas diffusion layer is disposed between the second metal plate and the membrane electrode assembly,
A fuel cell, wherein the one surface of the second metal plate faces the gas diffusion layer. The fuel cell according to claim 10 is stacked,
A fuel cell stack, wherein the first metal plate and the second metal plate of the adjacent fuel cells are in contact with each other at the top of the second protrusion.

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