JP7047090B2 - Gas supply diffusion layer for fuel cells, separators for fuel cells and fuel cell stack - Google Patents

Description

The present invention relates to a gas supply diffusion layer for a fuel cell, a separator for a fuel cell, and a fuel cell stack.

In the technical field of polymer electrolyte fuel cells (PEFCs), fuel cell stacks capable of uniformly supplying and diffusing fuel cell gases (anode gas, cathode gas) are known. (See, for example, Patent Document 1.). FIG. 20 is a front view schematically showing a conventional fuel cell stack 920. 21 and 22 are plan views of the type CA separator 921 in the conventional fuel cell stack 920. Of these, FIG. 21 is a plan view seen from the fuel cell gas supply / diffusion layer (cathode gas supply / diffusion layer) 942 side, and FIG. 22 is a plan view from the fuel cell gas supply / diffusion layer (anode gas supply / diffusion layer) 941 side. It is a plan view. FIG. 23 is a cross-sectional view taken along the line AA of FIG. 21.

As shown in FIGS. 20 to 23, the conventional fuel cell stack 920 has a plurality of separators having a structure in which a gas supply / diffusion layer for a fuel cell is provided on at least one surface of a metal plate 30 (a porous body layer). It has a structure in which a type CA separator 921, a type A separator 922, a type C separator 923, and a type AW separator 924) are laminated. The "A" of the type CA separator 921, the type A separator 922, and the type AW separator 924 represents the fuel cell gas supply diffusion layer (anode gas supply diffusion layer) 941, and the type CA separator 921 and type C. “C” of the separator 923 represents a fuel cell gas supply / diffusion layer (cathode gas supply / diffusion layer) 942, and “W” of the type AW separator 924 represents a cooling water supply / diffusion layer. According to the conventional fuel cell stack 920, since the fuel cell gas supply / diffusion layers 941 and 942 formed of the porous body layer are formed on the separator itself, the fuel cell gas is used as the fuel cell gas supply / diffusion layer. Can be spread evenly over the entire surface of. As a result, the gas for the fuel cell can be uniformly supplied over the entire surface of the membrane electrode assembly (MEA) 81, and the power generation efficiency of the fuel cell can be made higher than before.

International Publication No. 2015/072584

By the way, in the technical field of fuel cells, there is a demand for a technology capable of increasing the power generation efficiency of fuel cells as compared with the conventional case, and the same is true in the technical field of polymer electrolyte fuel cells. Therefore, an object of the present invention is to provide a gas supply diffusion layer for a fuel cell, a separator for a fuel cell, and a fuel cell stack, which can increase the power generation efficiency of the fuel cell as compared with the conventional case.

The fuel cell gas supply / diffusion layer according to one aspect of the present invention is a fuel cell gas supply / diffusion layer in which fuel cell gas flows from upstream to downstream during use, and permeates and diffuses the fuel cell gas. The porous body layer is provided with a conductive porous body layer, and the porous body layer has a gas diffusion portion made of the porous body and a plurality of isolated holes dispersed and arranged on one surface of the porous body layer. Each of the isolated holes is formed in the porous body layer isolated from each other, and is surrounded by the gas diffusion portion around the periphery except for the opening, and is composed of a recess having a bottom of the porous body.

The fuel cell separator according to one embodiment of the present invention is a fuel cell separator provided with a gas shielding plate and a fuel cell gas supply diffusion layer disposed on at least one surface of the gas shielding plate. The fuel cell gas supply / diffusion layer is the fuel cell gas supply / diffusion layer of the present invention, and the fuel cell gas supply / diffusion layer is described so that the plurality of isolated holes are located on the gas shielding plate side. It is arranged with respect to the gas shielding plate, and the gas flow path is formed by the isolated hole and the gas shielding plate.

The fuel cell stack according to one aspect of the present invention is a fuel cell stack in which a fuel cell separator and a membrane electrode assembly are laminated, and the fuel cell separator is the fuel cell separator of the present invention. The fuel cell separator and the membrane electrode assembly are in a positional relationship in which the membrane electrode assembly is located on the surface of the fuel cell gas supply diffusion layer on the side where the plurality of isolated holes are not formed. It is laminated with.

According to the gas supply diffusion layer for a fuel cell, the separator for a fuel cell, and the fuel cell stack according to one aspect of the present invention, the power generation efficiency of the fuel cell can be made higher than before, and the drainage property is superior to that of the conventional one. , Gas supply diffusion layer for fuel cell, separator for fuel cell and fuel cell stack.

It is a front view which shows typically the fuel cell stack 20 which concerns on embodiment. It is a side view which shows typically the fuel cell stack 20 which concerns on embodiment. It is a figure which shows for demonstrating the membrane electrode assembly (MEA) 81. It is a top view of the separator 23 for a fuel cell which concerns on embodiment. FIG. 4 is a cross-sectional view of FIG. It is a figure which shows for demonstrating the flow of the gas for a fuel cell. It is sectional drawing of the separator for a fuel cell (separator for a fuel cell 21, 22, 24, 25) other than the separator for a fuel cell 23. It is a top view of the gas supply diffusion layer 42a for a fuel cell which concerns on modification 1. FIG. It is a top view of the gas supply diffusion layer 42b for a fuel cell which concerns on modification 2. FIG. It is a top view of the gas supply diffusion layer 42c for a fuel cell which concerns on modification 3. FIG. It is a top view of the gas supply diffusion layer 42d for a fuel cell which concerns on modification 4. FIG. It is a top view of the gas supply diffusion layer 42e for a fuel cell which concerns on modification 5. FIG. It is a top view of the gas supply diffusion layer 42f for a fuel cell which concerns on modification 6. FIG. It is a top view of the gas supply diffusion layer 42g for a fuel cell which concerns on modification 7. FIG. It is a top view of the gas supply diffusion layer 42h for a fuel cell which concerns on modification 8. FIG. It is a top view of the gas supply diffusion layer 42i for a fuel cell which concerns on modification 9. FIG. It is a top view of the gas supply diffusion layer 42j for a fuel cell which concerns on modification 10. FIG. FIG. 17 is a partial cross-sectional view of FIG. It is sectional drawing of the separator 23k for a fuel cell which concerns on modification 11. It is a front view which shows typically the conventional fuel cell stack 920. It is a top view of the fuel cell separator 921 of the type CA in the conventional fuel cell stack 920. It is a top view of the fuel cell separator 921 of the type CA in the conventional fuel cell stack 920. It is sectional drawing which follows the AA line of FIG.

Hereinafter, the gas supply diffusion layer for a fuel cell, the separator for a fuel cell, and the fuel cell stack of the present invention will be described in detail using the embodiments shown in the figure.

[Embodiment]
FIG. 1 is a front view schematically showing a fuel cell stack 20 according to an embodiment. FIG. 2 is a side view schematically showing the fuel cell stack 20 according to the embodiment.

[Fuel cell cell stack]
The fuel cell stack 20 according to the embodiment is a polymer electrolyte fuel cell (PEFC). The fuel cell stack 20 has a plurality of single cells. A single cell of a fuel cell is conceptually composed of an electrolyte membrane (polymer film) (which may include a catalyst layer), an element constituting the cathode side and an element constituting the anode side sandwiching the electrolyte membrane (polymer film). Here, each cell of the fuel cell stack 20 has an element constituting the cathode side and an element constituting the anode side with the membrane electrode assembly 81 described later interposed therebetween. A plurality of cells are stacked with the separator interposed therebetween, forming a fuel cell cell stack 20.

The fuel cell separator according to the embodiment of the present invention includes a metal plate 30 that separates the cells, and is configured with various variations. In the fuel cell separator 21, the cathode gas supply / diffusion layer C is formed on one surface of the metal plate 30 as a gas shielding plate, and the anode gas supply / diffusion layer A is formed on the other surface (type CA separator). ). Therefore, the cathode gas supply / diffusion layer C and the anode gas supply / diffusion layer A of the type CA separator according to the embodiment of the present invention are incorporated into separate cells. The details of the type CA separator will be described later. The fuel cell separator 22 has an anode gas supply / diffusion layer A formed on one surface of a metal plate 30 (type A separator). The fuel cell separator 23 has a cathode gas supply diffusion layer C formed on one surface of a metal plate 30 (type C separator). In the fuel cell separator 24, the cathode gas supply / diffusion layer C is formed on one surface of the metal plate 30, and the cooling water supply / diffusion layer W is formed on the other surface (type CW separator).

Each cell is arranged so that the cathode side and the anode side alternate. The cathode gas supply / diffusion layer C and the anode gas supply / diffusion layer A are provided so as to face each other with the membrane electrode assembly (MEA) 81 interposed therebetween. In the embodiment, a cooling water supply diffusion layer W for supplying cooling water is provided every time two single cells are arranged. The cooling water supply / diffusion layer W may be provided every other single cell, or may be provided every three or more. Fuel cell separators 21 to 24 are combined and laminated so that the metal plate 30 (preferably the metal plate 30 in the type A or type C separator) faces the cooling water supply diffusion layer W.

Although not shown in FIGS. 1 and 2, the fuel cell stack of the present invention has an anode gas supply / diffusion layer A formed on one surface of the metal plate 30, and cooling water supply / diffusion on the other surface. A layer W may be formed (a type AW separator). Further, a separator (type W separator) in which the cooling water supply diffusion layer W is formed on one surface of the metal plate 30 may be provided. Further, a separator having cooling water supply diffusion layers W formed on both surfaces of the metal plate 30 may be provided. Details of the configuration of each fuel cell separator will be described later.

Current collector plates 27A and 27B are arranged at both ends of the stacked cells. Further, the end plates 75 and 76 are arranged on the outside of the current collector plates 27A and 27B via the insulating sheets 28A and 28B. The fuel cell separators 21 to 24 are pressed from both sides by the end plates 75 and 76. For the fuel cell separators located at both ends of the fuel cell stack 20 and in contact with the current collector plates 27A and 27B, it is preferable that the metal plate 30 (corrosion resistant layer) faces outward.

In FIGS. 1 and 2, the fuel cell separators 21 to 24, the membrane electrode assembly 81, the current collector plates 27A and 27B, the insulating sheets 28A and 28B, and the end plates 75 and 76 are shown in order to be easy to understand. Although drawn apart, they are closely joined to each other in the order shown in the sequence. The joining method is not particularly limited. For example, the members may be joined only by pressing the members from both sides with the end plates 75 and 76, or the members may be joined from both sides with the end plates 75 and 76 after adhering the appropriate positions of the members with an adhesive. It may be joined by pressing it, or it may be joined by another method. The thickness of each fuel cell separator 21 to 24, membrane electrode assembly 81, current collector plates 27A, 27B, insulating sheets 28A, 28B, etc. is, for example, about 100 μm to about 10 mm. Each figure in each embodiment of the present specification is drawn with exaggerated thickness.

An anode gas supply port 71A, a cathode gas discharge port 72B, and a cooling water discharge port 73B are provided at one end of the end plate 75 on the anode side. On the other hand, at one end of the end plate 76 on the cathode side (the side opposite to the one end of the end plate 75), the anode gas discharge port 71B, the cathode gas supply port 72A, and the cooling water supply port 73A (these are shown in FIG. 2). (Indicated by a broken line) are provided together. The corresponding fluid supply pipes and discharge pipes are connected to each of these supply ports and discharge ports, respectively.

The fuel cell separators 21 to 24 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 discharge port 72B, and cooling water, respectively. A cooling water outlet 63B communicating with the discharge port 73B is provided. Further, the separators 21 to 24 for each fuel cell have an anode gas outlet 61B communicating with the anode gas discharge port 71B, a cathode gas inlet 62A communicating with the cathode gas supply port 72A, and a cooling water supply port 73A, respectively. A cooling water inlet 63A communicating with the cooling water inlet 63A is provided.

Cathode gas, anode gas and cooling water are supplied through the anode gas supply port 71A, the cathode gas supply port 72A and the cooling water supply port 73A. In the embodiment, a case where hydrogen gas is used as the anode gas and air is used as the cathode gas is illustrated.

[Membrane electrode assembly]
Next, the membrane electrode assembly 81 will be described.
FIG. 3 is a diagram shown for explaining the membrane electrode assembly (MEA) 81. 3A is a plan view of the membrane electrode assembly 81, FIG. 3B is a front view of the membrane electrode assembly 81, and FIG. 3C is a side view of the membrane electrode assembly.

As shown in FIG. 3, the membrane electrode assembly 81 is arranged on the electrolyte membrane (PEM) 82, the catalyst layer (CL) 85 arranged on both sides of the electrolyte membrane 82, and the outer surface of each catalyst layer 85. It has a microporous layer (MPL) 83 and the like. In the embodiment, the one composed of the electrolyte membrane 82 and the catalyst layers 85 arranged on both sides thereof is referred to as a catalyst coated electrolyte membrane (CCM). The microporous layer 83 has pores (pores) having a diameter finer than that of the porous body layer 40. The microporous layer 83 may be omitted.

[Fuel cell separator, fuel cell gas supply diffusion layer]
Next, the fuel cell separators 21 to 24 and the fuel cell gas supply diffusion layer 42 will be described.
FIG. 4 is a plan view of the type C fuel cell separator 23 as viewed from the side of the metal plate 30. However, in FIG. 4, the metal plate 30 is not shown in order to clearly show the flow path pattern of the fuel cell separator 23. FIG. 5 is a cross-sectional view of FIG. 5 (a) is a cross-sectional view taken along the line A1-A4 of FIG. 4 (however, the portion A2-A3 is omitted), and FIG. 5 (b) is a cross-sectional view taken along the line A2-A3 of FIG. FIG. 5 shows a fuel cell separator 23 in a state where the membrane electrode assembly 81 is bonded in order to show the positional relationship between the fuel cell separator 23 and the membrane electrode assembly 81. Further, the cross-sectional structure of the membrane electrode assembly 81 is omitted. FIG. 6 is a diagram for explaining the flow of gas for a fuel cell. 6 (a) is an enlarged plan view of a portion B of FIG. 4, and FIG. 6 (b) is a cross-sectional view taken along the line CC of FIG. 6 (a).

Although the fuel cell separator 23 is formed with a plurality of isolated holes indicated by reference numeral 55, in FIG. 4, in order to make the figure easier to see, only some of the isolated holes are designated with reference numerals and other isolated holes are formed. Is omitted. Further, in FIGS. 4 to 6, the reference numerals 55 indicating the isolated holes may be followed by the reference numerals (551) to (553) in parentheses, but the reference numerals in the parentheses indicate the relative positional relationship of the isolated holes. It is shown for convenience of explanation, and does not indicate an isolated hole at a specific position. Further, in FIG. 6, the arrow indicates the flow of the cathode gas, the thick arrow indicates the overall flow of the cathode gas from the inflow side to the outflow side, and the thin arrow indicates the flow from the isolated hole 55 into the gas diffusion portion 43. The flow of the extruded cathode gas (underflow gas flow) is shown.

As shown in FIGS. 4 and 5, the fuel cell separator 23 has a structure in which the fuel cell gas supply diffusion layer 42 is formed on one surface of the metal plate 30. In FIG. 5, the metal plate 30 is hatched to indicate that it is a cross section. 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 the fuel cell separator 23, the cathode gas inlet 62A, the cooling water inlet 63A, and the anode are located at one end (lower part of FIG. 4) of the metal plate 30 in the vertical direction in the order of right, center, and left of FIG. A gas outlet 61B is provided. Further, at the other end (upper part of FIG. 4), a cathode gas outlet 62B, a cooling water outlet 63B, and an anode gas inlet 61A are provided in the order of left, center, and right in FIG.

Around each of the inlets 61A, 62A, 63A, the outlets 61B, 62B, 63B, and the formation region of the fuel cell gas supply diffusion layer 42, an electronically conductive or non-electronically conductive compact frame 32 is used. being surrounded. The compact frame 32 prevents leakage of the anode gas, the cathode gas and the cooling water. On the outer surface of the compact frame 32, along the compact frame 32 so as to surround the formation regions of the inlets 61A, 62A, 63A, the outlets 61B, 62B, 63B, and the gas supply diffusion layer 42 for the fuel cell. A groove 33A is formed (not shown in FIG. 4). A gasket (sealing material such as packing and O-ring) 33 is arranged in the groove 33A.

Corrosion-resistant layers having electron conductivity on both sides of the metal plate 30 except for the portions provided with the above-mentioned inlets 61A, 62A, 63A and outlets 61B, 62B, 63B. (Not shown in FIG. 5) is formed. Corrosion-resistant layers may be formed on the inner peripheral surfaces of the inlets 61A, 62A, 63A and the outlets 61B, 62B, 63B. A corrosion resistant layer may be formed on the side surface and the end surface 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 an effect of suppressing corrosion of the metal plate 30. At the stage where the fuel cell separators are combined to form the fuel cell stack as shown in FIG. 1 or 2, the gasket 33 is bonded to another fuel cell separator, membrane electrode assembly 81, or current collector plate 27A. It adheres to 27B and suppresses fuel leakage.

The fuel cell separator 23 is a type C fuel cell separator, and as shown in FIGS. 4 and 5, is located at the center of one surface of a rectangular metal plate 30 as a substrate, from the upstream side to the downstream side. A fuel cell gas supply / diffusion layer 42 is formed in which a cathode gas (fuel cell gas) flows toward the fuel cell to supply / diffuse the cathode gas. The fuel cell gas supply / diffusion layer 42 is a fuel cell gas supply / diffusion layer in which fuel cell gas flows from the upstream side to the downstream side during use, and permeates and diffuses the fuel cell gas to provide conductivity. The porous body layer 40 is provided. The porous body layer 40 has a gas diffusion portion 43 made of a porous body and a plurality of isolated holes 55 dispersed and arranged on one surface of the porous body layer 40. Each of the isolated holes 55 is formed in a porous body layer 40 isolated from each other, is surrounded by a gas diffusion portion 43 except for an opening, and is composed of a recess having a bottom of the porous body. Further, the porous body layer 40 has a gas inflow gutter 51 located in a corner on the inflow side of one surface and a gas outflow gutter 52 located in a corner on the outflow side of one surface (see FIG. 4). .. The porous body layer 40 may have a gas pressure equalizing groove 56 described later (deformed example 7) and a bypass groove 59 described later (deformed example 9), if necessary.

Hereinafter, the flow direction from the upstream side to the downstream side (direction from the side where the fuel cell gas inlet is provided to the side where the fuel cell gas outlet is provided, reference numeral Y in FIG. 4). The direction of the arrow in FIG. 4) is defined as the Y direction, and the width direction (direction of the arrow of reference numeral X in FIG. 4) perpendicular to the Y direction in a plane is described as the X direction.

The gas inflow side groove 51 has a narrow rectangular groove portion (step portion) extending in the width direction at the corner portion on the inflow side of the porous body layer 40 when viewed in a plane. Further, the gas inflow gutter 51 may have a plurality of branch groove portions (branch step portions) that branch from the rectangular groove portion (step portion) to the Y-direction outflow side so as to correspond to the isolated hole 55. .. For example, FIG. 4 depicts a plurality of branch groove portions (branch step portions) that branch to the outflow side in the Y direction in the shape of a circular isolated hole 55 cut out from a rectangular groove portion (step portion). The gas inflow gutter 51 is formed at a predetermined depth.

The gas outflow side groove 52 has a narrow rectangular groove portion (step portion) extending in the width direction at the corner portion on the outflow side of the porous body layer 40 when viewed in a plane. Further, the gas outflow gutter 52 may have a plurality of branch groove portions (branch step portions) that branch from the rectangular groove portion (step portion) to the inflow side in the Y direction so as to correspond to the isolated hole 55. .. For example, FIG. 4 depicts a plurality of branch groove portions (branch step portions) that branch to the inflow side in the Y direction in a shape obtained by cutting out a circular isolated hole 55 from a rectangular groove portion (step portion). The gas outflow gutter 52 is formed at the same depth as the gas inflow gutter 51.

In the fuel cell gas supply diffusion layer according to the embodiment, the isolated holes 55 are dispersed and arranged over a desired range on one surface of the porous body layer 40. Each isolated hole 55 preferably has a shape having a predetermined regularity, and the position of the center of gravity of each isolated hole 55 is preferably arranged on one surface of the porous body layer 40 with a predetermined regularity. .. Here, the desired range is a range surrounded by a closed curve connecting the positions of the centers of gravity of the outer isolated holes among the isolated holes formed on one surface of the porous body layer 40 (indicated by reference numeral R in FIG. 4). The range surrounded by the two-dot chain line). The desired range may cover 60% or more of the surface area of one of the porous body layers, preferably 70% or more, and more preferably 80% or more. The desired range may be dispersed and arranged over the entire surface of one surface of the porous body layer 40. Further, the fact that the isolated holes are arranged in a dispersed manner does not mean only when they are arranged side by side at equal pitches in the X direction and the Y direction, and are scattered in a desired range without much bias. It means that it is arranged.

The isolated hole 55 has an area of a desired range (a planar projection range of the isolated holes formed on one surface of the porous body layer 40, which is surrounded by a closed curve connecting the positions of the centers of gravity of the outer isolated holes. Area) is S1, and the total area of the plurality of isolated holes 55 (the total area of the planar projected areas of the isolated holes for all the isolated holes constituting the plurality of isolated holes 55) is S2. , It is preferable that they are arranged so as to satisfy the relationship of "0.9 × S1 ≧ S2 ≧ 0.1 × S1".

Further, the isolated holes 55 may all have the same shape and size, or only the shape may be the same and the size may be changed. It is preferable that the isolated holes 55 are arranged with regularity, at least in a desired range.

Further, the shape of the bottom of the isolated hole 55 may be flat in parallel with the membrane electrode assembly 81 or the electrolyte membrane (PEM) 82, or the depth thereof may differ depending on the location.

Therefore, in the fuel cell gas supply diffusion layer 42 according to the embodiment, since the plurality of isolated holes 55 are arranged on one surface of the porous body layer 40, when the fuel cell gas flows through the isolated holes 55. Since the movement resistance is smaller than that of the gas diffusion portion 43 and the flow is smooth, it is possible to supply a larger amount of fuel cell gas to the membrane electrode assembly 81 than before.

Further, since the fuel cell gas supply diffusion layer 42 according to the embodiment has a plurality of isolated holes 55 formed on one surface of the porous body layer 40, the gas supply diffusion layer 42 is arranged on the other surface of the porous body layer 40. Since the fuel cell gas is always supplied to the provided membrane electrode assembly 81 via the porous body (gas diffusion unit 43), a plurality of gas flow paths are formed from one surface of the porous body layer 40 to the other. The fuel cell gas can be uniformly supplied to the membrane electrode assembly as compared with the case where the gas is formed over the surface of the membrane electrode.

Further, since the isolated hole is surrounded by the porous body (gas diffusion section 43), the isolated hole on the downstream side always proceeds through the porous body (gas diffusion section 43), so that the isolated hole is porous. The fuel cell gas can be uniformly diffused over the entire porous body layer 40 as compared with the case where the gas flow path is formed in the body layer 40 so as to be connected from the inflow side to the outflow side.

As a result, the fuel cell gas supply diffusion layer 42 according to the embodiment can uniformly supply a larger amount of fuel cell gas to the membrane electrode assembly 81 than before, so that the fuel cell can be supplied more uniformly than before. It is a gas supply diffusion layer for fuel cells that can increase the power generation efficiency of fuel cells.

Further, since the fuel cell gas supply diffusion layer 42 according to the embodiment has the above-mentioned characteristics, the fuel cell gas (in this case, cathode gas (oxygen gas, nitrogen gas)) that has not been used for power generation can be used. Since the fuel cell gas can be efficiently discharged to the outside of the fuel cell gas supply diffusion layer 42 through the porous body (gas diffusion portion 43) and the isolated hole 55, the movement resistance of the fuel cell gas is lower than before, and by extension, The reaction gas concentration is kept high, and the fuel cell gas supply / diffusion layer can be used to increase the fuel cell power generation efficiency.

Further, since the gas supply diffusion layer 42 for a fuel cell according to the embodiment has the above-mentioned characteristics, the water vapor or aggregated water generated by the membrane electrode assembly 81 at the time of power generation is made into a porous body (gas diffusion unit 43). ) And the isolated hole 55 so that the gas can be efficiently discharged to the outside of the fuel cell gas supply / diffusion layer 42, so that the fuel cell gas supply / diffusion layer has better drainage than the conventional one.

Each isolated hole 55 may have a shape having a variable width, and may be, for example, a circle, an ellipse, a rhombus, a triangle, or the like when viewed in a plane. Each isolated hole 55 may be formed at the same depth as the gas inflow gutter 51 and the gas outflow gutter 52, and at a constant depth. A gas diffusion portion 43 made of a porous body is exposed on the inner surface of each isolated hole 55.

In this way, if the plurality of isolated holes 55 have a configuration in which the width changes such as a circle, an ellipse, a rhombus, or a triangle, it is possible to supply the fuel cell gas in a two-dimensional manner. ..

It is preferable that the isolated holes are arranged with regularity in the positional relationship between the isolated hole of one of the plurality of isolated holes and the isolated hole adjacent to the downstream side of the isolated hole. As shown in FIG. 4, the isolated hole 55 has the longest distance along the X direction from the isolated hole 551 among the isolated holes located on the downstream side from the isolated hole 551 of the plurality of isolated holes 55. The first isolated hole is a short isolated hole (that is, the isolated hole having the smallest absolute value of the X-direction component of the vector connecting the position of the center of gravity of the isolated hole 551 and the position of the center of gravity of the adjacent isolated hole (including the case where the absolute value is zero, of course). The X-direction component of the vector connecting the isolated hole 552 and the isolated hole having the second shortest distance along the X direction from the isolated hole 551 (that is, the position of the center of gravity of the isolated hole 551 and the position of the center of gravity of the adjacent isolated hole 551). When the isolated hole with the second smallest absolute value) is set as the second isolated hole 553, it is the distance between the one isolated hole 551 and the first adjacent isolated hole 552, which is the opening of the one isolated hole 551. The distance between the first isolation hole L1 which is the shortest distance between the first isolation hole 552 and the opening of the first proximity isolation hole 552, and the distance between the one isolation hole 551 and the second proximity isolation hole 553, and the one isolation hole 551. The second interval L2, which is the shortest distance between the opening of the second proximity isolated hole 553 and the opening of the second proximity isolated hole 553, may satisfy the relationship of “L2 ≦ L1” as shown in FIG. , One isolated hole 551 includes a first proximity isolated hole 552 arranged in the Y direction (the shortest distance along the X direction) and a second proximity isolated hole 553 located in the adjacent row (both adjacent rows). Although they are close to each other, the distance that the fuel cell gas passes through the gas diffusion portion 43 when moving from the one isolated hole 551 to the second adjacent isolated hole 553 is from the one isolated hole 551 to the first adjacent isolated hole 552. When moving to, the distance is shorter than the distance through the gas diffusion portion 43. In this way, the fuel cell gas extruded from the one isolated hole 551 is the first than the first proximity isolated hole 552. 2 It becomes easier to flow toward the proximity isolated hole 553. Therefore, the gas for the fuel cell extruded from the one isolation hole 551 goes toward the second proximity isolation hole 553 more than toward the first proximity isolation hole 552. Therefore, the gas for the fuel cell can be uniformly diffused over the entire porous body layer 40.

Further, as shown in FIG. 4, the first interval L1 and the second interval L2 may further satisfy the relationship of “L1 <2 × L2”. That is, since the distance between the one isolated hole 551 and the second proximity isolated hole 553 is the same as the distance between the second proximity isolated hole 553 and the first proximity isolated hole 552, the fuel cell gas is one isolated hole 551. The distance passing through the gas diffusion unit 43 when directly moving from the first proximity isolated hole 552 to the first proximity isolated hole 552 via the second proximity isolated hole 553 is the distance from the one isolated hole 551. It should be shorter than the distance through the gas diffusion unit 43. In this way, when the fuel cell gas moves directly from the one isolated hole 551 to the first proximity isolated hole 552, the distance through the gas diffusion portion 43 (first interval L1) is such that the fuel cell gas is one. It is shorter than the distance (2 × second interval L2) that passes through the gas diffusion unit 43 when moving from the isolated hole 551 to the first proximity isolated hole 552 via the second proximity isolated hole 553. Therefore, the flow of the fuel cell gas directly from the one isolated hole 551 to the first proximity isolated hole 552 does not become extremely small, and the fuel cell gas is diffused in a well-balanced manner over the entire porous body layer 40. Can be done.

When the relationship of "L2≤L1" and the relationship of "L1 <2 x L2" are satisfied, the values of the pitch in the X direction and the pitch in the Y direction between the isolated holes are set to "L2". It may be appropriately set within the range that satisfies the relationship of "≦ L1" and the relationship of "L1 <2 × L2".

In the gas supply diffusion layer for a fuel cell according to the embodiment, an area of a desired range (a closed curve connecting the positions of the centers of gravity of the outer isolated holes among the isolated holes formed on one surface of the porous body layer 40). Area of the planar projection range of the enclosed area) S1 and the total area S2 of the plurality of isolated holes are arranged so as to satisfy the relationship of "0.9 × S1 ≧ S2 ≧ 0.1 × S1". Is preferable for the following reasons. That is, when the above S2 is 10% or more of the above S1, the movement resistance when the fuel cell gas flows in a desired range can be sufficiently reduced, so that the membrane electrode assembly 81 can be compared with the conventional one. This is because a large amount of fuel cell gas can be supplied. Further, when S2 is 90% or less of S1, a region where the fuel cell gas diffuses and sinks within a desired range can be secured at a minimum, so that the fuel cell gas can be uniformly distributed within the desired range. This is because it can be easily diffused. From the viewpoint of supplying a larger amount of fuel cell gas, the area S1 of the porous body layer 40 and the total area S2 of the plurality of isolated holes satisfy the relationship of “S2 ≧ 0.2 × S1”. It is more preferable, and it is even more preferable to satisfy the relationship of "S2 ≧ 0.3 × S1". Further, from the viewpoint of diffusing within a desired range, it is more preferable to satisfy the relationship of "0.8 × S1 ≧ S2", and even more preferably to satisfy the relationship of “0.7 × S1 ≧ S2”. ..

The gas diffusion portion 43 is made of a porous body having conductivity and having fine voids formed therein. The gas diffusion unit 43 has a substantially rectangular shape when viewed in a plane. The gas diffusion unit 43 is formed with a porosity suitable for allowing a gas or liquid to flow underground through the voids. Details will be described later.

In addition, in this specification, "underground river" means a gas inflow side groove 51, each isolated hole 55, a gas pressure equalization groove 56 (modification example 7) described later, and a bypass groove 59 (modification example 9) described later. It refers to the flow of cathode gas (underground gas) extruded into the gas diffusion unit 43 from the above.
Further, in the present specification, "from the inflow side to the outflow side of the gas" means "almost along the Y direction in which the gas flows", and "toward the outflow side from the inflow side of the gas". Is the direction of flow of the gas in the porous body layer 40 as a whole along the Y direction. This is a case where the cathode gas inlet 62A and the cathode gas outlet 62B are arranged at diagonal positions of the metal plate 30 as in the fuel cell gas supply diffusion layer 42 according to the embodiment. The path does not have to be formed along the diagonal line described above, and as in the embodiment, the direction of "from the inflow side to the outflow side of the gas" is "the porous body when viewed as the whole porous body layer 40". When the direction of the gas flow in the layer 40 is from the bottom to the top of the paper in FIG. 4 in the Y direction, as shown in FIG. 4, along the Y direction from the bottom to the top of the paper in FIG. The isolation holes 55 may be aligned as long as they are aligned, or may be aligned along other directions.

Further, the fuel cell separator 23 will be described in detail. Air (oxygen gas and nitrogen gas) as the cathode gas diffuses in the porous body layer 40 (gas diffusion unit 43). The porous body layer 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 by the binding property of the polymer resin. The fluid resistance of the porous body layer 40 depends on the porosity of the porous body layer and the area of the surface on which the fluid flows. The larger the porosity, the smaller the fluid resistance. The larger the area through which the fluid flows, the smaller the fluid resistance. As a rough guide, in the gas supply diffusion layer 42 for a fuel cell (for cathode gas), the porosity of the porous body layer 40 is about 50 to 85%. In the fuel cell gas supply diffusion layer 41 (for the anode gas), the porosity of the porous body layer 40 is about 30 to 85%.

Since the pore ratio of the porous body layer 40 is configured as described above, the cathode gas and water vapor between the isolated hole 55 and the porous body layer 40 pass through the inner surface of the gas flow path groove 55. As a result of proper circulation of condensed water, a large amount of fuel cell gas can be uniformly supplied to the membrane electrode assembly, and cathode gas that was not used during power generation and during power generation. The generated steam and condensed water can be efficiently discharged to the outside of the isolated hole. As a result, in the gas supply diffusion layer 42 for a fuel cell, the isolated hole 55 is a gas permeation layer in which a large number of fine gas flow holes are opened in a gas impermeable layer made of metal, ceramics, resin, etc. on the inner surface of the isolated hole 55. It is not necessary to form something like a filter, and the gas diffusion portion 43 made of a porous body is configured to be exposed on the inner surface.

By adjusting the content of the carbon-based conductive material, the pore ratio of the fuel cell gas supply diffusion layer 42 can be adjusted, and by extension, the moving resistance of 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 movement resistance decreases (the porosity increases). On the contrary, when the content of the carbon-based conductive material is lowered, the movement resistance becomes large (the porosity becomes small). 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 conductivity by an appropriate content of the carbon-based conductive material.

The carbon-based conductive material is not particularly limited, and for example, graphite, carbon black, diamond-coated carbon black, silicon carbide, titanium carbide, carbon fiber, carbon nanotubes and the like can be used. As the polymer resin, either a thermosetting resin or a thermoplastic resin can be used. Examples of the polymer resin include phenol resin, epoxy resin, melamine resin, rubber resin, furan resin, vinylidene fluoride resin and the like.

An inflow passage 57 is formed between the cathode gas inflow port 62A and the region where the porous body layer 40 is formed (see FIG. 4). An outflow passage 58 is formed between the cathode gas outlet 62B and the region where the porous body layer 40 is formed. These inflow passages 57 and outflow passages 58 are for supporting the membrane electrode assembly 81 or its frame 81A. Therefore, any structure may be used as long as it can smoothly flow the cathode gas and support the membrane electrode assembly 81. For example, it may be a porous body layer having an extremely large porosity, or it may be a structure in which a large number of columns are arranged. In the region of the porous body layer 40 facing the inflow passage 57, an elongated inflow gutter 51 is formed along the width direction of the metal plate 30. Further, an elongated outflow gutter 52 is formed along the width direction of the metal plate 30 in the region of the porous body layer 40 facing the outflow passage 58. However, the inflow side groove 51 and the outflow side groove 52 may be omitted.

As shown in FIG. 5, the porous body layer 40, the inflow passage 57, and the outflow passage 58 are formed at the same height (thickness) as the compact frame 32. A plurality of isolated holes 55 composed of voids are provided on the surface of the fuel cell gas supply diffusion layer 42 on the side facing the metal plate 30, and a plurality of isolated holes 55 are provided in the gaps between the plurality of isolated holes 55 and the metal plate 30. Gas flow path is formed. A plurality of isolated holes 55 are formed in the arrangement as described above. Each isolated hole 55 diffuses the fuel cell gas that has flowed in through the gas diffusion unit 43 by forced underground flow by reducing the movement resistance, expanding the gas, and causing the gas to flow out to the gas diffusion unit 43 again. The number and structure of the isolated holes 55 are not limited to those shown in the figure.

When the fuel cell gas supply diffusion layer 42 according to the embodiment is used for a fuel cell for transportation equipment, the width of the porous body layer 40 is, for example, 30 mm, although it depends on the type and size of the transportation equipment. It is about 300 mm. The width W of the isolated hole 55 is, for example, about 0.3 mm to 2 mm. The thickness of the porous body layer 40 is, for example, about 150 to 400 μm, the depth of the isolated hole 55 is, for example, about 100 to 300 μm, and the distance between the bottom of the isolated hole and the other surface of the porous body layer 40 ( The ceiling thickness) is, for example, about 100 to 300 μm. When the gas supply diffusion layer 42 for a fuel cell according to the embodiment is used for a fuel cell for an application other than transportation equipment (for example, for stationary use), the size is not limited to the above, and the required performance and the like can be obtained. Depending on the size, an appropriate size can be used.

The fuel cell gas supply / diffusion layer 41 in the type A fuel cell separator 22 basically has the same configuration as the fuel cell gas supply / diffusion layer 42. However, since the gas supplied to the fuel cell gas supply diffusion layer is hydrogen gas, the pore ratio is lower and the thickness is thinner than that of the fuel cell gas supply diffusion layer 42 (FIG. 7 (b) described later). reference.).

In the fuel cell separator 21 of the type CA, the fuel cell gas supply / diffusion layer 41 and the fuel cell gas supply / diffusion layer 42 are used as the fuel cell gas supply / diffusion layer (see FIG. 7A described later). The type CW fuel cell separator 24 has a cooling water supply / diffusion layer formed on a surface of the type C fuel cell separator 23 on which the fuel cell gas supply / diffusion layer 42 is not formed (see a figure to be described later). 7 (c).). The type AW fuel cell separator 25 has a cooling water supply / diffusion layer formed on a surface of the type A fuel cell separator 22 on which the fuel cell gas supply / diffusion layer 41 is not formed (see a figure to be described later). 7 (d).).

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 in the membrane electrode assembly 81 and move to the oxygen electrode side, and react with oxygen to generate water. The generated water is discharged from the oxygen electrode side. At this time, in the fuel cell separator 23 provided with the fuel cell gas supply diffusion layer 42 having the above structure, the air flowing in from the cathode gas inflow port 62A flows from the inflow passage 57 and the inflow side groove 51 to the gas diffusion portion 43. The air that has entered and submerged passes through the isolated hole 55 to reduce the distance through which the porous body has a large movement resistance, so that the air passes through the isolated hole 55 and heads toward the outflow side. The air flowing into the isolated hole 55 spreads in the isolated hole 55, is pushed out again from the inner surface of the isolated hole 55 to the gas diffusion portion 43, is forced underground, and diffuses in various directions.

Explaining in more detail that the air travels between the isolated holes 55 toward the outflow side with reference to FIGS. 4 and 6 (a), the isolated holes 55 are hollow and the movement resistance of the air is higher than that of the gas diffusion portion 43. Also, the air tends to pass through the isolated hole 55 rather than through the gas diffuser 43. Therefore, the air extruded in the plane direction from the one isolated hole 551 to the gas diffusion portion 43 flows underground toward the first proximity isolated hole 552 or the second proximity isolated hole 553 adjacent to the downstream side. In particular, when the first interval L1 and the second interval L2 satisfy the relationship of "L1 ≦ L2", the distance passing through the gas diffusion portion 43 from the one isolated hole 551 to the second proximity isolated hole 553 (the first). The distance (2 intervals L2) is the same as or shorter than the distance (first interval L1) passing through the gas diffusion portion 43 to the first proximity isolated hole 552, and most of the air extruded from the one isolated hole 551 is in the X direction. Underground toward the second proximity isolated hole 553. The air that has flowed into the second proximity isolated hole 553 is pushed out to the gas diffusion portion 43 again, and similarly, underground flows toward the isolated hole adjacent to the upstream of the second proximity isolated hole 553. By such repetition, the air travels between the isolated holes 55 and heads toward the outflow side.

Further, when the first interval L1 and the second interval L2 further satisfy the relationship of "L1 <2 x L2", the gas diffusion portion 43 directly from the one isolated hole 551 to the first proximity isolated hole 552 passes through. From the distance (2 × second interval L2) that the distance (first interval L1) passes through the gas diffusion portion 43 from the one isolated hole 551 to the first proximity isolated hole 552 via the second proximity isolated hole 553. Shortened, a portion of the air is subsoiled by a route directly from one isolated hole 551 to the first proximity isolated hole 552.

Further, as shown in FIG. 6B, the air diffuses in the porous body layer 40 (gas diffusion unit 43) in the planar direction and also in the thickness direction, and the porous body layer 40 (gas diffusion). It is supplied to the membrane electrode assembly 81 provided in contact with the portion 43) and contributes to the power generation reaction. The gas not used for power generation (unused oxygen gas and nitrogen gas) and the water generated during power generation (steam or condensed water) form the porous body layer 40 (gas diffusion portion 43), the isolated hole 55, and the outflow side groove 52. It flows out to the outflow passage 58 through the outflow passage 58. The oxygen gas, nitrogen gas and water flowing out to the outflow passage 58 are finally discharged from the outflow passage 58 through the cathode gas outlet 62B and the cathode gas discharge port 72B. At this time, due to the structure of the gas supply diffusion layer 42 for the fuel cell, all the water is not discharged, and a part of the water remains in the porous body layer 40 (gas diffusion portion 43).

Since the fuel cell gas supply diffusion layer 42 according to the embodiment has the above-mentioned characteristics, the water (water vapor or condensed water) generated by the membrane electrode assembly during power generation is transferred to the porous body layer 40 and the isolated hole. It becomes possible to efficiently discharge to the outside of the isolated hole via 55. Further, in the underground river region, water can be efficiently discharged to the outside of the isolated hole in the form of being pushed out by the underground gas flow.

Further, when the fuel cell gas supply / diffusion layer 42 according to the embodiment is used for the fuel cell gas supply / diffusion layer for cathode gas, a particularly remarkable effect can be obtained. In this case, since it has the above-mentioned characteristics, the cathode gas that has not been used for power generation can be efficiently recovered through the gas diffusion portion 43 (porous body) and the isolated hole 55. It is a gas supply / diffusion layer for fuel cells that can further increase the power generation efficiency of fuel cells. Furthermore, since it has the above-mentioned characteristics, the water vapor or aggregated water generated in the membrane electrode assembly 81 during power generation can be efficiently recovered through the gas diffusion unit 43 (porous body) and the isolated hole 55. Therefore, it becomes a gas supply diffusion layer for a fuel cell having better drainage than before.

The fuel cell gas supply diffusion layer 42 according to the embodiment has a particularly remarkable effect when the cathode gas is air. In this case, since it has the above-mentioned characteristics, the nitrogen gas that is not used for power generation can be efficiently discharged through the gas diffusion portion 43 (porous body) and the isolated hole 55, so that it can be efficiently discharged as compared with the conventional case. It is a fuel cell gas supply / diffusion layer that can reduce the movement resistance of the fuel cell gas and further increase the power generation efficiency of the fuel cell.

The fuel cell separator 23 according to the embodiment is a fuel cell separator provided with a metal plate 30 and a fuel cell gas supply diffusion layer disposed on at least one surface of the metal plate 30 for a fuel cell. The gas supply / diffusion layer is the fuel cell gas supply / diffusion layer 42 according to the embodiment, and the fuel cell gas supply / diffusion layer 42 is made of metal so that a plurality of gas flow path grooves 55 are located on the metal plate 30 side. Since it is arranged with respect to the plate 30 and the gas flow path is composed of the gas flow path groove 55 and the metal plate 30, the power generation efficiency of the fuel cell can be made higher than before, and further, the conventional method. It is also a separator for fuel cells with excellent drainage.

Further, the fuel cell stack 20 according to the embodiment is a fuel cell stack in which a fuel cell separator and a membrane electrode joint are laminated, and the fuel cell separator is for a fuel cell according to the embodiment. The separator 23 is a fuel cell separator 23 and the membrane electrode joint 81 is a membrane electrode joint on the surface of the fuel cell gas supply diffusion layer 42 on the side where a plurality of gas flow path grooves 55 are not formed. Since the 81s are stacked in a positional relationship, the fuel cell stack can have higher power generation efficiency than the conventional one, and has better drainage than the conventional one.

[Manufacturing method of separator 23 for fuel cell]
As an example, the corrosion resistant layer, the compact frame 32, the gas supply diffusion layer 42 for a fuel cell, and the like are formed by isotropic pressure pressurization. For example, when a thermosetting resin is used (a thermoplastic resin may be used), a carbon-based conductive material powder (and carbon fiber depending on the situation), a resin powder and a volatile solvent are kneaded into a paste. A large number of types of this paste are prepared, such as those for a corrosion resistant layer, those for a dense frame, and those for a fluid supply / diffusion layer. Then, a corrosion resistant layer, a pattern of the dense frame 32, a pattern of the gas supply / diffusion layer 42 for a fuel cell, and the like are sequentially formed on the metal plate 30 by printing, stamping, squeezing, and the like. The solvent is volatilized for each pattern formation. The entire metal plate 30 on which all the above patterns are formed is placed in a soft thin rubber bag, degassed into a vacuum, then the rubber bag is placed in a pressure-resistant container, the heating fluid is introduced into the container, and the heating fluid is heated. Isotropic pressure is applied to cure the resin. In order to make the height (thickness) of the compact frame 32 and the gas supply diffusion layer 42 for the fuel cell finally the same height (thickness), each of these depends on the degree of shrinkage during resin curing. It is preferable to adjust the height (thickness) of the frame, wall, layer, etc. at the time of pattern production.

On the one hand, a corrosion-resistant layer may be formed on the metal plate 30, and on the other hand, a compact frame 32 and a gas supply / diffusion layer 42 for a fuel cell may be formed, and finally these may be thermocompression bonded. At this time, the compact frame 32 may be formed at the same time as the corrosion resistant layer on the metal plate 30. In the first step, a corrosion-resistant layer and a compact frame 32 are created on the metal plate 30, and then in the second step, the paste of the gas supply diffusion layer 42 for a fuel cell is sequentially printed on the corrosion-resistant layer of the metal plate 30 and dried. After that, it can be manufactured by curing with a roll press (hot press).

Alternatively, the following manufacturing method can also be used. Carbon fiber (CF), a small amount of black smoke fine particles (GCB), and a resin that forms a thermoplastic or thermosetting or fibrous material that serves as a binder are kneaded to form a sheet, which is green before curing. In the sheet state, a stamp mold having protrusions having a shape corresponding to the inflow passage 57, the outflow passage 58, the inflow side groove 51, the outflow side groove 52 and the isolated hole 55 is pressed against the sheet, and the inflow passage 57, the outflow passage 58, The inflow side groove 51, the outflow side groove 52 and the isolated hole 55 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 gas supply diffusion layer 42 for a fuel cell is the area of the plane orthogonal to the porosity of the porous body layer 40 and the flow direction of the fluid (height (thickness) and width of each layer). Dependent. The larger the porosity, the smaller the movement resistance. The larger the area in which the fluid flows, the smaller the moving resistance (the moving resistance per unit area is constant). As a rough guide, the pore ratio of the gas supply / diffusion layer for fuel cells is about 30 to 85% for the gas supply / diffusion layer 42 for fuel cells (for anode gas), and the gas supply / diffusion for fuel cells (for cathode gas). The layer 41 is about 50 to 85%. The porosity P is determined by P = (volume of pores in the porous body layer) / (volume of the porous body layer), which is easy to measure. Here, the pores are true pores including pores that do not lead to the outside.

The above-mentioned manufacturing method is also used when manufacturing a fuel cell separator (fuel cell separator 21, fuel cell separator 22, fuel cell separator 24, and fuel cell separator 25) other than the fuel cell separator 23. Applicable.

[Fuel cell separator other than fuel cell separator 23]
FIG. 7 is a cross-sectional view of a fuel cell separator (fuel cell separator 21, fuel cell separator 22, fuel cell separator 24, and fuel cell separator 25) other than the fuel cell separator 23. 7 (a) is a cross-sectional view of a type CA fuel cell separator 21, FIG. 7 (b) is a cross-sectional view of a type A fuel cell separator 22, and FIG. 7 (c) is a type CW fuel. It is sectional drawing of the separator 24 for a battery, and FIG. 7 (d) is a sectional view of the separator 25 for a fuel cell of type AW.

The fuel cell gas supply / diffusion layer of the present invention is applied to the fuel cell gas supply / diffusion layer 42 (for cathode gas) and / or the fuel cell gas supply / diffusion layer 41 (for anode gas) of the fuel cell separator 21. (See FIG. 7 (a)). Further, the fuel cell gas supply / diffusion layer of the present invention can be applied to the fuel cell gas supply / diffusion layer 41 (for the anode gas) of the fuel cell separator 22 (see FIG. 7B). Further, the fuel cell gas supply / diffusion layer of the present invention can be applied to the fuel cell gas supply / diffusion layer 42 (for the cathode gas) of the fuel cell separator 24 (FIG. 7c). ). Further, the fuel cell gas supply / diffusion layer of the present invention can be applied to the fuel cell gas supply / diffusion layer 41 (for the anode gas) of the fuel cell separator 25 (see FIG. 7B).

As described above, even when the gas supply / diffusion layer for a fuel cell of the present invention is applied to the gas supply / diffusion layer for a fuel cell of the fuel cell separators 21, 22, 24, 25 as described above, the amount is larger than before. Since the fuel cell gas can be uniformly supplied to the membrane electrode joint, the fuel cell gas supply diffusion layer can be made higher in fuel cell power generation efficiency than in the past.

[Configuration Example 1]
As one embodiment of the present invention, a configuration example of a gas supply / diffusion layer for a fuel cell as shown in FIG. 4 can be shown. That is, in FIG. 4, in addition to the basic configuration as described above, as a predetermined regularity, on a plurality of lines extending in the Y direction arranged at equal pitches (X pitches) in the X direction, equal pitches (Y pitches) in the Y direction. It is arranged in. Assuming that the isolated holes 55 are arranged in the Y direction in one row and n rows from the end side in the X direction, the positions in the Y direction of the odd-numbered rows and the even-numbered rows are the same, and the odd-numbered rows and the even-numbered rows are arranged in the Y direction. The position is off by half the Y pitch (so-called staggered pattern configuration). In this way, the isolated holes 55 are arranged with regularity in the X direction and the Y direction. Further, in FIG. 4, each isolated hole 55 has the same shape including the shape and size, and each isolated hole 55 is arranged on one surface of the porous body layer 40. Each isolated hole 55 has a shape having a variable width, and is specifically circular. Each isolated hole 55 is formed at the same depth as the gas inflow gutter 51 and the gas outflow gutter 52, and at a constant depth. A gas diffusion portion 43 made of a porous body is exposed on the inner surface of each isolated hole 55.

By doing so, in addition to the above-mentioned effect, since the plurality of isolated holes 55 are dispersed over the entire surface of one surface of the porous body layer 40, the fuel cell gas is spread over the entire porous body layer 40. It can be diffused evenly.

[Modification 1]
FIG. 8 is a diagram shown for explaining the planar structure (viewed from the side of the metal plate 30) of the fuel cell gas supply diffusion layer 42a according to the first modification. However, as in the case of FIG. 4, the metal plate 30 is not shown in order to clearly show the flow path pattern of the fuel cell separator 23. The same applies to FIGS. 9 to 17 thereafter.

The fuel cell gas supply / diffusion layer 42a according to the first modification basically has the same configuration as the fuel cell gas supply / diffusion layer 42 according to the embodiment, but the planar shape of the isolated hole is the fuel according to the embodiment. This is different from the case of the battery gas supply diffusion layer 42. That is, as shown in FIG. 8, in the fuel cell gas supply diffusion layer 42a according to the first modification, the isolated hole 55a having a diamond-shaped planar shape is used as the isolated hole.

According to the fuel cell gas supply / diffusion layer 42a according to the first modification, the same effects as those of the fuel cell gas supply / diffusion layer 42 according to the embodiment can be obtained, and the following effects can be obtained. That is, since the isolated holes 55a have a flat wall surface and the wall surfaces of the adjacent isolated holes 55a can be arranged in parallel, the fluid resistance between the isolated holes 55a becomes constant in a wide range to some extent. , The fuel cell gas can be more evenly submerged.

[Modification 2]
FIG. 9 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42b according to the second modification.

The fuel cell gas supply / diffusion layer 42b according to the second modification basically has the same configuration as the fuel cell gas supply / diffusion layer 42 according to the embodiment, but the planar shape of the isolated hole is the fuel according to the embodiment. This is different from the case of the battery gas supply diffusion layer 42. That is, as shown in FIG. 9, in the fuel cell gas supply diffusion layer 42b according to the modified example 2, the isolated hole has a plane shape (in this case, a rectangle extending along the Y direction) having a constant width as an isolated hole. 55b is used.

According to the fuel cell gas supply / diffusion layer 42b according to the second modification, the same effect as that of the fuel cell gas supply / diffusion layer 42 according to the embodiment can be obtained, and the following effects can be obtained. That is, since the width of the isolated hole 55b is constant, that is, the planar shape is square or rectangular, the isolated hole 55b is used as the entire surface of one surface of the porous body layer, particularly when the planar shape of the porous body layer is rectangular. Can be easily placed across.

[Modification 3]
FIG. 10 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42c according to the modified example 3.

The fuel cell gas supply / diffusion layer 42c according to the third modification basically has the same configuration as the fuel cell gas supply / diffusion layer 42 according to the embodiment, but the planar shape of the isolated hole is the fuel according to the embodiment. This is different from the case of the battery gas supply diffusion layer 42. That is, as shown in FIG. 10, in the fuel cell gas supply diffusion layer 42c according to the modified example 3, the isolated hole 55c, which is an isolated groove extending along an oblique direction, is used as the isolated hole.

According to the fuel cell gas supply / diffusion layer 42c according to the third modification, the same effects as those of the fuel cell gas supply / diffusion layer 42 according to the embodiment can be obtained, and the following effects can be obtained. That is, since the isolated hole 55c is an isolated groove extending along an oblique direction, the fuel cell gas can be expanded in the X direction and advanced in the Y direction.

[Modification 4]
FIG. 11 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42d according to the modified example 4.

The fuel cell gas supply / diffusion layer 42d according to the fourth modification basically has the same configuration as the fuel cell gas supply / diffusion layer 42 according to the embodiment, but the planar shape of the isolated hole is the fuel according to the embodiment. This is different from the case of the battery gas supply diffusion layer 42. That is, as shown in FIG. 11, in the fuel cell gas supply diffusion layer 42d according to the modified example 4, the isolated hole 55d that is bent in the middle is used as the isolated hole. Examples of the shape of the isolated hole 55d that is bent in the middle include an L-shape as shown in FIG. 11, a U-shape, a C-shape, an arc, and the like. The isolated holes 55d are intermittently arranged along the zigzag line represented by the two-dot chain line G in FIG.

According to the fuel cell gas supply / diffusion layer 42d according to the fourth modification, in addition to obtaining the same effect as the fuel cell gas supply / diffusion layer 42 according to the embodiment, the isolated hole 55d is bent in the middle. As a result, the effect that the fuel cell gas can be quickly changed in direction and spread can be obtained.

[Modification 5]
FIG. 12 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42e according to the modified example 5.

The fuel cell gas supply / diffusion layer 42e according to the modified example 5 basically has the same configuration as the fuel cell gas supply / diffusion layer 42b according to the modified example 2, but the planar structure of the isolated hole is described in the modified example 2. This is different from the case of the fuel cell gas supply diffusion layer 42b. That is, as shown in FIG. 12, in the fuel cell gas supply diffusion layer 42e according to the modified example 4, the isolated hole 55e is formed so that the area seen in a plane becomes smaller stepwise as it goes to the downstream side. ing. FIG. 12 shows an example in which a rectangular isolated hole is configured in the same manner as that shown in FIG. Here, as the isolated hole 55e moves from the inflow side to the outflow side, the length (width) of the rectangular isolated hole 55e in the X direction is formed so as to be gradually narrowed as W1> W2> W3.

According to the fuel cell gas supply / diffusion layer 42e according to the modification 5, the same effect as that of the fuel cell gas supply / diffusion layer 42b according to the modification 2 can be obtained, and the following effects can be obtained. That is, since the area of the isolated hole 55e seen in a plane gradually decreases toward the downstream side, it corresponds to the flow rate of the fuel cell gas that decreases toward the downstream side. Therefore, the concentration of the fuel cell gas on the upstream side and the downstream side becomes more uniform, and the fuel cell gas can be efficiently diffused.

[Modification 6]
FIG. 13 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42f according to the modified example 6.

The fuel cell gas supply / diffusion layer 42f according to the modified example 6 basically has the same configuration as the fuel cell gas supply / diffusion layer 42b according to the modified example 2, but the planar structure of the isolated hole is described in the modified example 2. This is different from the case of the fuel cell gas supply diffusion layer 42b. That is, as shown in FIG. 13, in the fuel cell gas supply diffusion layer 42f according to the modified example 6, the isolated hole 55f is formed so that the area seen in a plane becomes smaller stepwise as it goes to the downstream side. ing. FIG. 13 shows an example in which a rectangular isolated hole 55e is configured on the same as that shown in FIG. Here, as the isolated hole 55f moves from the inflow side to the outflow side, the length of the rectangular isolated hole 55e in the Y direction is gradually shortened as D1> D2> D3.

According to the fuel cell gas supply / diffusion layer 42f according to the modification 6, the same effect as that of the fuel cell gas supply / diffusion layer 42b according to the modification 2 can be obtained, and the following effects can be obtained. That is, since the area of the isolated hole 55f seen in a plane gradually decreases toward the downstream side, it corresponds to the flow rate of the fuel cell gas that decreases toward the downstream side. Therefore, the concentration of the fuel cell gas on the upstream side and the downstream side becomes more uniform, and the fuel cell gas can be efficiently diffused.

In the modified example 5 and the modified example 6, both are shown as rectangular isolated holes (55e, 55f) as isolated holes, but the size (area) of the isolated holes is reduced toward the downstream side. Then, the isolated hole may have other shapes such as a circle, an ellipse, a rhombus, and a triangle. Further, the optimum shape may be used for each isolated hole.

[Modification 7]
FIG. 14 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42 g according to the modified example 7.

The fuel cell gas supply / diffusion layer 42g according to the modification 7 has basically the same configuration as the fuel cell gas supply / diffusion layer 42b according to the modification 2, but further has a groove for equalizing the gas pressure. This is different from the case of the fuel cell gas supply diffusion layer 42b according to the second modification. That is, as shown in FIG. 14, in the fuel cell gas supply diffusion layer 42g according to the modified example 7, the porous body layer 40 has the width of the porous body layer 40 on one surface of the porous body layer 40. It further has one or more gas pressure equalizing grooves 56 (two gas pressure equalizing grooves 56 in FIG. 14) that are fully extended. The gas pressure equalizing groove 56 is formed in two places so as to substantially divide the porous body layer 40 into three equal parts in the Y direction. The gas pressure equalizing groove 56 is formed to have a depth equivalent to that of the isolated hole 55 g. Since the gas pressure equalizing groove 56 is provided, the isolated hole 55g is the gas pressure equalizing groove 56s, the inflow side groove 51 and the gas pressure equalizing groove 56, or the gas pressure equalizing groove 56 in one surface of the porous body layer 40. They are dispersed and arranged over a range (desired range) sandwiched between the outflow side groove 52 and the gas pressure equalization groove 56, respectively.

According to the fuel cell gas supply / diffusion layer 42g according to the modification 7, in addition to obtaining the same effect as the fuel cell gas supply / diffusion layer 42b according to the modification 2, the width direction of the porous body layer 40 By having the gas pressure equalizing groove 56 fully extended, it is possible to obtain the effect that the supply amount of the fuel cell gas can be made more uniform over the entire width direction of the porous body layer 40.

[Modification 8]
FIG. 15 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42h according to the modified example 8.

The fuel cell gas supply / diffusion layer 42h according to the modified example 8 basically has the same configuration as the fuel cell gas supply / diffusion layer 42g according to the modified example 7, but the number of gas pressure equalizing grooves and isolation The planar structure of the hole is different from that of the fuel cell gas supply diffusion layer 42 g according to the modified example 7. That is, as shown in FIG. 15, in the fuel cell gas supply diffusion layer 42h according to the modified example 8, only one gas pressure equalizing groove 56 is formed. Further, in the fuel cell gas supply diffusion layer 42h according to the modification 8, the distance between the plurality of isolated holes 55h that are close to each other in the width direction (X direction) becomes gradually narrower toward the downstream side. It has become. More specifically, in the isolated hole 55h, the distance P2 between the isolated holes 55h on the downstream side of the gas pressure equalizing groove 56 is narrower than the distance P2 between the isolated holes 55h on the upstream side of the gas pressure equalizing groove 56. ing. Further, the width of the isolated hole 55h on the downstream side of the gas pressure equalizing groove 56 is narrower than the width on the upstream side of the gas pressure equalizing groove 56. In the modified example 8), since the configuration example includes one gas pressure equalizing groove 56, the isolated hole 55h is the inflow side groove 51 and the gas pressure equalizing groove 56 in one surface of the porous body layer 40. Or, they are dispersed and arranged over a range (desired range) sandwiched between the outflow side groove 52 and the gas pressure equalizing groove 56. However, as in the modified example 7, the gas pressure equalizing groove 56 is further added, and the gas pressure equalizing grooves 56 are added to each other, the inflow side groove 51 and the gas pressure equalizing groove 56, or the outflow side groove 52 and the gas pressure equalizing groove. It may be distributed and arranged over a range (desired range) sandwiched between the grooves 56. In the modified example 8, the size, shape, and dispersion of the isolated holes 55h are set for each range (desired range) sandwiched between the inflow gutter 51 and the gas pressure equalizing groove 56, or the outflow gutter 52 and the gas pressure equalizing groove 56. It is arranged by replacing the arrangement rule of arrangement individually.

According to the fuel cell gas supply / diffusion layer 42h according to the modification 8, in addition to the same effect as the fuel cell gas supply / diffusion layer 42g according to the modification 7, the following effects can be obtained. That is, since the distance between the isolated holes 55h adjacent to each other in the X direction is gradually narrowed, the number of the isolated holes 55h aligned in the direction along the X direction is gradually increased. Therefore, even if the pressure loss increases toward the downstream side, the submerged fuel cell gas and the water vapor or aggregated water generated by the membrane electrode assembly during power generation are densely arranged in the isolated holes on the downstream side. It becomes easier to flow in, and the gas for the fuel cell can be diffused more uniformly, and the water vapor or aggregated water generated in the membrane electrode assembly 81 at the time of power generation can be more efficiently discharged to the outside of the gas supply diffusion layer 42h for the fuel cell. Further, the fuel cell gas can be diffused more uniformly downstream of the gas pressure equalizing groove 56.

[Modification 9]
FIG. 16 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42i according to the modified example 9.

The fuel cell gas supply / diffusion layer 42i according to the modification 9 basically has the same configuration as the fuel cell gas supply / diffusion layer 42b according to the modification 2, but is further modified in that it has a bypass groove. This is different from the case of the fuel cell gas supply diffusion layer 42b according to 2. That is, as shown in FIG. 16, in the fuel cell gas supply diffusion layer 42i according to the modified example 9, the porous body layer 40 is on one surface of the porous body layer 40 on the inflow side of the fuel cell gas. It further has a bypass groove 59 (a bypass groove 59A for inflow) extending from the center to the central portion. Further, in the fuel cell gas supply diffusion layer 42i according to the modified example 9, the porous body layer 40 is a bypass groove 59 (a bypass groove for outflow) extending from the central portion to the outflow side of the fuel cell gas. It also has 59B).

Each bypass groove 59 (59A, 59B) is a groove in which thin rectangular portions are combined. Each bypass groove 59 (59A, 59B) is formed at the same depth as the inflow side groove 51 or the outflow side groove 52 that communicates with each other. The inflow bypass groove 59A is formed by combining a feed groove portion 591A, a widening groove portion 592A, and a plurality of branch groove portions 593A. The inflow side of the feed groove portion 591A is connected to the vicinity of one end of the inflow side groove 51 in the X direction, and extends in the Y direction from the inflow side groove 51 to the central portion of the porous body layer 40. The widening groove portion 592A extends in the X direction from the tip end side of the feed groove portion 591A. A plurality of branch groove portions 593A extend from the widened groove portion 592A to the outflow side in the Y direction so as to correspond to the continuous pattern shape of the isolated holes 55i. The outflow bypass groove 59B is formed by combining a feed groove portion 591B, a widening groove portion 592B, and a plurality of branch groove portions 593B. In the feed groove portion 591B, the outflow side is connected to the vicinity of the other end portion of the outflow side groove 52 in the X direction, and extends from the outflow side groove 52 to the central portion of the porous body layer 40 in the Y direction. The widening groove portion 592B extends in the X direction from the tip end side of the feed groove portion 591B. A plurality of branch groove portions 593B extend from the widening groove portion 592B to the inflow side in the Y direction so as to correspond to the continuous pattern shape of the isolated holes 55i. The widening groove portion 592A in the inflow bypass groove 59A is arranged on the outflow side of the widening groove portion 592B in the outflow bypass groove 59B. The widening groove portion 592A in the inflow bypass groove 59A extends in the X direction to the extent that it does not intersect the feed groove portion 591B in the outflow bypass groove 59B. The widening groove portion 592B in the outflow bypass groove 59B extends in the X direction to the extent that it does not intersect the feed groove portion 591A in the inflow bypass groove 59A. With this configuration, a first block between the inflow gutter 51 and the widening groove portion 592B and a second block between the outflow gutter 52 and the widening groove portion 592B are configured. The fuel cell gas flows separately in the first block and the second block. Therefore, the fuel cell gas passing through both blocks is almost zero. In this modification, isolated holes 55i are arranged in this block, that is, in each range (desired range) sandwiched between the inflow gutter 51 and the widening groove portion 592B, or the outflow gutter 52 and the widening groove portion 592B. There is. At this time, the size and shape of the isolated holes 55i and the arrangement rules of the distributed arrangement may be individually changed and arranged.

According to the fuel cell gas supply / diffusion layer 42i according to the modification 9, the same effect as that of the fuel cell gas supply / diffusion layer 42b according to the modification 2 can be obtained, and the following effects can be obtained. That is, the porous body layer 40 has a bypass groove 59 (bypass groove 59A for inflow) extending from the inflow side of the fuel cell gas to the central portion, so that the porous body layer 40 is reduced upstream from the central portion. Since the fuel cell gas that has been exhausted is replenished in the central portion, it is possible to suppress a decrease in power generation efficiency downstream of the central portion. Further, the porous body layer 40 has a bypass groove 59 (a bypass groove 59B for outflow) extending from the central portion to the outflow side of the fuel cell gas, so that the porous body layer 40 is upstream from the central portion. Since the water vapor or aggregated water generated in the membrane electrode assembly 81 during power generation is efficiently discharged from the central portion, it is possible to suppress a decrease in power generation efficiency downstream of the central portion.

In the fuel cell gas supply diffusion layers 42a to 42i according to the modified examples 1 to 9, one isolated hole 551a to 551i (one isolated hole 551h1,551h2 in the modified example 8) and the first proximity isolated hole 552a to The first spacing L1 (first spacing L11, L12 in the modified example 8) of the 552i (first proximity isolated hole 552h1,552h2 in the modified example 8), one isolated hole 551a to 551i, and the second proximity isolated hole 553a to 553i. The second spacing L2 (second spacing L12, L22 in the modified example 8) of the second proximity isolated hole 553h1, 553h2 in the modified example 8 is "L2 ≦ L1" and "L1" as in the case of the embodiment. <2 x L2 "is satisfied.

Further, in FIGS. 10 (Modified 3) and 11 (Modified 4), among the isolated holes located downstream from the isolated holes 551c and 551d, the isolated holes 551c and 551d are located along the X direction. X of the vector connecting the position of the center of gravity of the isolated hole 551c, 551d and the position of the center of gravity of the adjacent isolated hole (that is, the position of the center of gravity of the isolated hole 551c, 551d) which is the third shortest or is equivalent to the second adjacent isolated hole 553c, 553d. An isolated hole having the third smallest absolute value of the directional component or the second smallest isolated hole equivalent to another isolated hole) is drawn as the third proximity isolated hole 554c, 554d. The distance between the one isolated hole 551c, 551d and the third proximity isolated hole 554c, 554d is not particularly limited, but is preferably shorter than the first distance L1 so as to spread more widely.

[Modification 10]
FIG. 17 is a diagram shown for explaining the planar structure of the fuel cell gas supply diffusion layer 42j according to the modified example 10. FIG. 18 is a cross-sectional view taken along the line EE in FIG.

The fuel cell gas supply / diffusion layer 42j according to the modified example 10 basically has the same configuration as the fuel cell gas supply / diffusion layer 42b according to the modified example 2, but the bottom shape of the isolated hole is the same as that of the modified example 2. This is different from the case of the fuel cell gas supply diffusion layer 42b. That is, as shown in FIG. 18, in the fuel cell gas supply diffusion layer 42j according to the modified example 10, the isolated holes are isolated holes in which the bottom surface of each isolated hole is inclined so as to become deeper toward the downstream side. 55j is used. In the modified example 10, a rectangular isolated hole 55j is used in the plan view, but at this time, the size and shape of the isolated hole 55j and the arrangement rule of the distributed arrangement are set in other modified examples. It may be arbitrarily replaced as follows.

According to the fuel cell gas supply / diffusion layer 42j according to the modification 10, the same effect as that of the fuel cell gas supply / diffusion layer 42b according to the modification 2 can be obtained, and the bottom surface of each isolated hole is on the downstream side. Since it is inclined so as to become deeper toward the surface, the flow of the fuel cell gas flowing in each isolated hole 55j includes a vector toward the membrane electrode assembly 81. Therefore, the fuel cell gas flowing back from the isolated hole 55j tends toward the membrane electrode assembly 81, and more fuel cell gas can be supplied to the membrane electrode assembly 81.

[Modification 11]
FIG. 19 is a cross-sectional view of the fuel cell gas supply diffusion layer 42k according to the modified example 11. Similar to the case of FIG. 5, the fuel cell separator 23k in a state where the membrane electrode assembly 81 is bonded is shown. In the above-described embodiment, as the fuel cell gas supply / diffusion layer, a fuel cell gas supply / diffusion layer 42 having a porous body layer 40 having a plurality of isolated holes 55 formed on one surface thereof is used (Fig.). 5), the present invention is not limited thereto. As shown in FIG. 19, a fuel comprising a porous body layer 40 having a plurality of isolated holes 55 formed on one surface and a microporous layer 44 disposed on the other surface of the porous body layer 40. A battery gas supply diffusion layer can also be used. With such a configuration, a fuel cell separator can be configured by using a membrane electrode assembly that does not have a microporous layer.

The gas supply diffusion layer for a fuel cell, the separator for a fuel cell, and the fuel cell stack of the present invention have been described above based on the illustrated embodiments, but the present invention is not limited to the above embodiments. , Various modifications can be carried out without departing from the gist of the present invention.

[1] In the above-described embodiment, as the isolated hole, the width of the isolated hole on the surface of the porous body layer 40 (or the isolated hole 55) is equal to the width of the gas flow path groove at the bottom of the isolated hole 55. However, the isolated hole 55 having a rectangular cross section is used (see FIGS. 5 and 7), but the present invention is not limited thereto. An isolated hole having a triangular cross section in which the bottom of the groove is narrower than the surface may be used, an isolated hole having a semicircular cross section in which the bottom of the groove is narrower than the surface may be used, or an isolated hole having another shape may be used. You may use it.

[2] In the above-described embodiment, the metal plate 30 is used as the gas shielding plate, but the present invention is not limited thereto. A plate (for example, a ceramic plate, a resin plate) made of a material having a property of shielding gas other than the metal plate 30 may be used.

[3] Each of the above modifications applies the features described in each modification to the fuel cell gas supply diffusion layer 42, the fuel cell separator 23, and the fuel cell stack 20 according to the embodiment. The features described in each modification are not limited to this, and can be applied to the fuel cell gas supply diffusion layer, the fuel cell separator, and the fuel cell stack of the present invention in general. For example, the features described in each modification are the type CA fuel cell gas supply / diffusion layer 21, the type A fuel cell gas supply / diffusion layer 22, the type CW fuel cell gas supply / diffusion layer 24, and the type AW. It is also applicable to the fuel cell gas supply diffusion layer 25, and the fuel cell separator and fuel cell cell stack provided with these fuel cell gas supply diffusion layers.

[4] Each of the above-mentioned modifications is described by modifying only a characteristic part with respect to the above-described embodiment or the above-mentioned other modifications, but each part may be combined and modified as appropriate. Is also possible. For example, by combining the modified examples 5 to 9, the isolated holes 55 are formed to be narrower and shorter toward the outflow side, and the intervals between the isolated holes 55 adjacent to each other in the X direction are narrowed, and the groove for equalizing the gas pressure is formed. The fuel cell separator 23 in which the 56 and the bypass groove 59 are formed may be configured.

[5] In the above embodiment and each of the above modifications, the isolated holes 55 having the same shape are described as being arranged at a constant pitch in the X direction, but the present invention is not limited thereto. For example, it may be configured by combining a plurality of types of isolated holes having completely different shapes, or may be arranged so that the pitch in the X direction changes.

[6] The above-described embodiment and the above-mentioned modifications 1 to 10 have been described assuming that the depths of the isolated holes and the grooves are the same, but the present invention is not limited thereto. For example, the depth of the isolated hole or groove may be different for each isolated hole or groove, or may vary within the isolated hole or groove.

[7] Each of the above modifications applies the features described in each modification to the fuel cell gas supply diffusion layer 42, the fuel cell separator 23, and the fuel cell stack 20 according to the embodiment. The features described in each modification are not limited to this, and can be applied to the fuel cell gas supply diffusion layer, the fuel cell separator, and the fuel cell stack of the present invention in general. For example, the features described in each modification are the type CA fuel cell gas supply / diffusion layer 21, the type A fuel cell gas supply / diffusion layer 22, the type CW fuel cell gas supply / diffusion layer 24, and the type AW. It is also applicable to the fuel cell gas supply diffusion layer 25, and the fuel cell separator and fuel cell cell stack provided with these fuel cell gas supply diffusion layers.

20 Fuel cell stack 21,22,23,24,25 Fuel cell separator 27A, 27B Current collector plate 28A, 28B Insulation sheet 30 Metal plate 32 Dense frame 33 Gasket 33A Gasket groove 40 Porous body layer 41 For fuel cell Gas supply diffusion layer (anode gas supply diffusion layer)
42, 42a-42k Gas supply diffusion layer for fuel cells (cathode gas supply diffusion layer)
43 Gas diffuser 44 Microporous layer 51 Inflow side groove 52 Outflow side groove 55, 55a to 55j Isolated hole 56 Gas pressure equalization groove 57 Inflow passage 58 Outflow passage 59 Bypass groove 59A Inflow bypass groove 59B Outflow bypass Groove 61A Anode gas inlet 61B Anode gas outlet 62A Cathode gas inlet 62B Cathode gas outlet 63A Cooling water inlet 63B Cooling water outlet 74 Tightening / spring support 75, 76 End plate 80 Cell structure 81 Membrane electrode assembly 81A Frame (frame)
82 Electrolyte Membrane 83 Microporous Layer 85 Catalyst Layers 551,551a-551i One Isolated Hole 552,552a-552i First Proximity Isolated Hole 535,553a-553i Second Proximity Isolated Hole L1, L11, L21 First Spacing L2, L12 , L22 2nd interval W1 to W3 Length (width) of isolated hole in Y direction
D1 to D3 Length of isolated holes in the X direction P1, P2 Spacing between isolated holes in the X direction

Claims (18)

A fuel cell gas supply diffusion layer in which fuel cell gas flows from the upstream side to the downstream side during use.
It is provided with a porous body layer that permeates and diffuses the fuel cell gas and has conductivity.
The porous body layer has a gas diffusion portion made of the porous body and a plurality of isolated holes dispersed and arranged on one surface of the porous body layer.
Each of the isolated holes is isolated from each other and formed in the porous body layer.
The circumference excluding the opening is surrounded by the gas diffusion portion, and is composed of a recess having a bottom of a porous body .
When the direction from the upstream side to the downstream side is the Y direction and the width direction orthogonal to the Y direction in a plane is the X direction, the plurality of isolated holes are scattered in the X direction and the Y direction. A gas supply diffusion layer for a fuel cell, which is characterized in that it is arranged in the same direction . A fuel cell gas supply diffusion layer in which fuel cell gas flows from the upstream side to the downstream side during use.
It is provided with a porous body layer that permeates and diffuses the fuel cell gas and has conductivity.
The porous body layer has a gas diffusion portion made of the porous body and a plurality of isolated holes dispersed and arranged on one surface of the porous body layer.
Each of the isolated holes is isolated from each other and formed in the porous body layer.
The circumference excluding the opening is surrounded by the gas diffusion portion, and is composed of a recess having a bottom of a porous body.
When the direction from the upstream side to the downstream side is the Y direction and the width direction orthogonal to the Y direction in a plane is the X direction, the plurality of isolated holes are scattered in the X direction and the Y direction. Placed in
A gas supply diffusion layer for a fuel cell, wherein the bottom surface of each isolated hole is inclined so as to become deeper toward the downstream side. In the fuel cell gas supply diffusion layer according to claim 1 or 2 .
Among the isolated holes located on the downstream side of one of the plurality of isolated holes, the isolated hole having the shortest distance along the X direction from the one isolated hole is defined as the first proximity isolated hole. When the isolated hole having the second shortest distance along the X direction from the one isolated hole is defined as the second proximity isolated hole, the first distance L1 between the one isolated hole and the first proximity isolated hole, A gas supply diffusion layer for a fuel cell, characterized in that the first isolated hole and the second interval L2 of the second proximity isolated hole satisfy the relationship of “L2 ≦ L1”. In the gas supply diffusion layer for a fuel cell according to claim 3 .
The fuel cell gas supply diffusion layer is characterized in that the first interval L1 and the second interval L2 satisfy the relationship of "L1 <2 x L2". In the fuel cell gas supply diffusion layer according to any one of claims 1 to 4 .
Of the isolated holes formed on one surface of the porous body layer, the area of the range surrounded by the closed curve connecting the positions of the centers of gravity of the outer isolated holes is defined as S1, and the total area of the plurality of isolated holes is defined as S2. When the fuel cell is used, the gas supply / diffusion layer for a fuel cell is characterized by satisfying the relationship of “0.9 × S1 ≧ S2 ≧ 0.1 × S1”. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 5 .
A gas supply diffusion layer for a fuel cell, characterized in that the porous body is exposed in the isolated hole. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 6.
A gas supply diffusion layer for a fuel cell, characterized in that at least a part of the isolated holes has a variable width. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 6.
A gas supply diffusion layer for a fuel cell, wherein at least a part of the isolated holes has a constant width. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 8.
A gas supply diffusion layer for a fuel cell, wherein at least a part of the isolated holes is an isolated groove extending in an oblique direction. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 9.
A gas supply diffusion layer for a fuel cell, characterized in that at least a part of the isolated holes of the plurality of isolated holes is bent in the middle. In the gas supply diffusion layer for a fuel cell according to any one of claims 1 to 10.
The plurality of isolated holes are formed so that the area seen in a plane becomes smaller stepwise toward the downstream side, and the gas supply diffusion layer for a fuel cell is characterized. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 11.
The plurality of isolated holes are a gas supply diffusion layer for a fuel cell, characterized in that the distance between the isolated holes adjacent to each other in the width direction is gradually narrowed toward the downstream side. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 12.
A gas supply diffusion layer for a fuel cell, further comprising one or a plurality of gas pressure equalizing grooves extending in the width direction of the porous body layer on one surface of the porous body layer. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 13.
One or more bypass grooves extending from at least the inflow side of the fuel cell gas to the central portion or extending from the central portion to the outflow side of the fuel cell gas on one surface of the porous body layer. Further, a gas supply diffusion layer for a fuel cell, which is characterized by having. In the fuel cell gas supply diffusion layer according to any one of claims 1 to 14.
The fuel cell gas supply / diffusion layer, wherein the fuel cell gas supply / diffusion layer is a fuel cell gas supply / diffusion layer for cathode gas. In the gas supply diffusion layer for a fuel cell according to claim 15.
A gas supply diffusion layer for a fuel cell, wherein the cathode gas is air. A fuel cell separator comprising a gas shield plate and a fuel cell gas supply diffusion layer disposed on at least one surface of the gas shield plate.
The fuel cell gas supply / diffusion layer is the fuel cell gas supply / diffusion layer according to any one of claims 1 to 16.
The gas supply diffusion layer for a fuel cell is arranged with respect to the gas shielding plate so that the plurality of isolated holes are located on the gas shielding plate side.
A separator for a fuel cell, characterized in that a gas flow path is formed by the isolated hole and the gas shielding plate. A fuel cell stack in which a separator for a fuel cell and a membrane electrode assembly are laminated.
The fuel cell separator is the fuel cell separator according to claim 17.
The fuel cell separator and the membrane electrode assembly are laminated in a positional relationship in which the membrane electrode assembly is located on the surface of the fuel cell gas supply diffusion layer on the side where the plurality of isolated holes are not formed. A fuel cell stack characterized by being.

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