JP2022169222A - Separator for fuel cell - Google Patents

Abstract

To provide a separator for a fuel cell that can suppress an increase in reaction gas pressure loss at a narrowed portion.SOLUTION: A cathode separator 70 includes a first gas flow path 81 and a second gas flow path 82 and a rib 90. The first gas flow path 81 is provided with a first narrowed portion 83A. The rib 90 is provided with a first communication groove 91 that communicates the first narrowed portion 83A of the first gas flow path 81 and the second gas flow path 82 with each other. A first end 91a of the first communication groove 91 communicating with the first gas flow path 81 is provided at a position upstream of a second end 91b in the extending direction of a gas flow path 80.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fuel cell separator.

Patent Literature 1 discloses a fuel cell that includes a membrane electrode assembly and two separators sandwiching the membrane electrode assembly. One separator is arranged on the fuel electrode side of the membrane electrode assembly. The other separator is arranged on the air electrode side of the membrane electrode assembly.

Each separator has a plurality of gas flow paths extending in parallel with each other at intervals and through which reaction gases flow, and rib portions extending along the gas flow paths between adjacent gas flow paths. there is

A fuel gas such as hydrogen is supplied to the gas flow path of the separator arranged on the fuel electrode side. An oxidizing gas such as air is supplied to the gas flow path of the separator arranged on the air electrode side. Electricity is generated by an electrochemical reaction between the fuel gas and the oxidizing gas inside the membrane electrode assembly. Along with this electrochemical reaction, water is generated inside the membrane electrode assembly.

In order to discharge such water from the inside of the membrane electrode assembly, in Patent Document 1, a narrowed portion is provided in the gas flow path of the separator arranged on the air electrode side. The constricted portion is formed by the bottom surface of the gas channel protruding toward the membrane electrode assembly side more than other portions. Water is discharged from the inside of the membrane electrode assembly into the gas channel by the reaction gas entering the inside of the membrane electrode assembly by the narrowed portion. The water discharged in this manner is discharged to the outside through the gas channel by the pressure of the reaction gas flowing through the gas channel.

JP 2019-200909 A

By the way, at the constricted portion provided in the gas channel, since the cross-sectional area of the channel is smaller than that of other portions, the pressure loss of the reaction gas may increase. Such an increase in the pressure loss of the reaction gas may lead to deterioration in the performance of the fuel cell. Therefore, it is desired to suppress the increase in the pressure loss of the reaction gas.

A fuel cell separator for solving the above-mentioned problems comprises a plurality of gas flow paths extending in parallel with each other at intervals and through which reactant gases flow, and a plurality of gas flow paths between the gas flow paths adjacent to each other. and a rib extending along the gas flow path, wherein the gas flow path is provided with a constricted portion having a partially reduced cross-sectional area of the flow path, wherein the gas flow path is When upstream and downstream in the flow direction of the flowing reaction gas are simply referred to as upstream and downstream respectively, the plurality of gas flow paths are the first gas flow path provided with the constricted portion and adjacent to the first gas flow path. and a second gas flow path that aligns with the second gas flow path, and the rib is provided with a communication groove that allows communication between the narrowed portion of the first gas flow path and the second gas flow path, and the communication groove The first end of the groove that communicates with the first gas flow path is aligned with the second end of the communication groove that communicates with the second gas flow path in the extending direction of the gas flow path, or the second end of the groove communicates with the second gas flow path. It is provided at a position on the upstream side of the end.

According to this configuration, the throttle portion of the first gas flow path and the second gas flow path communicate with each other through the communication groove. Therefore, part of the reaction gas flowing through the constricted portion of the first gas flow path flows toward the second gas flow path through the communication groove. Therefore, it is possible to suppress an increase in the pressure loss of the reaction gas at the constricted portion.

1 is a cross-sectional view showing a schematic configuration of a fuel cell provided with a fuel cell separator according to one embodiment; FIG. The perspective view of the separator for fuel cells of the same embodiment. The top view of the separator for fuel cells of the same embodiment. The top view of the separator for fuel cells of a 1st modification. The top view of the separator for fuel cells of a 2nd modification. The top view of the separator for fuel cells of the 3rd example of a change. The top view of the separator for fuel cells of the 4th modification. The top view of the separator for fuel cells of the 5th modification. FIG. 11 is a plan view of a fuel cell separator according to a sixth modification;

An embodiment of a fuel cell separator will be described below with reference to FIGS. 1 to 3. FIG.
(Cell stack 10)
As shown in FIG. 1, the fuel cell includes a cell stack 10 in which a plurality of power generation cells 11 are stacked.

The power generation cell 11 includes a sheet-like membrane electrode gas diffusion layer assembly 20 and two separators 30 sandwiching the membrane electrode gas diffusion layer assembly 20 in the thickness direction.
The membrane electrode gas diffusion layer assembly 20 has a membrane electrode assembly 21 , an anode gas diffusion layer 25 and a cathode gas diffusion layer 26 .

The membrane electrode assembly 21 has an electrolyte layer 22 formed of, for example, a solid polymer membrane, and an anode electrode layer 23 and a cathode electrode layer 24 sandwiching the electrolyte layer 22 in the thickness direction.

The anode gas diffusion layer 25 covers the surface of the anode electrode layer 23 opposite to the electrolyte layer 22 . The cathode gas diffusion layer 26 covers the surface of the cathode electrode layer 24 opposite to the electrolyte layer 22 . The anode gas diffusion layer 25 and the cathode gas diffusion layer 26 are both made of carbon fiber, for example.

(Separator 30)
Separator 30 includes anode separator 40 and cathode separator 70 . The anode separator 40 is provided on the surface of the anode gas diffusion layer 25 opposite to the anode electrode layer 23 . The cathode separator 70 is provided on the surface of the cathode gas diffusion layer 26 opposite to the cathode electrode layer 24 .

The separator 30 has, for example, a rectangular plate shape. As the material of the separator 30, for example, a metal material such as titanium, or a composite material containing conductive particles and a resin material can be used.

The anode separator 40 has a plurality of gas flow paths 50 extending in parallel with each other at intervals, and a plurality of ribs 60 extending along the gas flow paths 50 between adjacent gas flow paths 50 . there is That is, the anode separator 40 has gas channels 50 and ribs 60 alternately arranged in parallel.

The gas channel 50 has a groove shape that opens toward the membrane electrode gas diffusion layer assembly 20 . Hydrogen gas as a reaction gas flows through each gas channel 50 .
The cathode separator 70 has a plurality of gas passages 80 extending in parallel with each other at intervals, and a plurality of ribs 90 extending along the gas passages 80 between adjacent gas passages 80 . there is That is, the cathode separator 70 is provided with gas channels 80 and ribs 90 alternately arranged in parallel.

The gas channel 80 has a groove shape that opens toward the membrane electrode gas diffusion layer assembly 20 . Air as a reaction gas flows through each gas channel 80 .
In the power generation cell 11 , the anode separator 40 is arranged such that the top surface of each rib 60 is in contact with the anode gas diffusion layer 25 . Thereby, the hydrogen gas flowing through each gas channel 50 is supplied to the anode electrode layer 23 through the anode gas diffusion layer 25 .

Cathode separator 70 is positioned such that the top surface of each rib 90 contacts cathode gas diffusion layer 26 . Thereby, the air flowing through each gas flow path 80 is supplied to the cathode electrode layer 24 through the cathode gas diffusion layer 26 .

In the membrane electrode assembly 21, the hydrogen gas supplied to the anode electrode layer 23 and the air supplied to the cathode electrode layer 24 electrochemically react to generate electricity. Along with such an electrochemical reaction, water (hereinafter referred to as generated water) is generated inside the membrane electrode assembly 21 . The produced water is discharged to the outside of the fuel cell through the gas channel 80 by the pressure of the air flowing through the gas channel 80 of the cathode separator 70 .

The power generating cell 11 generates heat as the power is generated. Therefore, between two adjacent power generation cells 11, a coolant flow path 31 through which a coolant for cooling the power generation cells 11 flows is provided. The coolant channel 31 is provided between the adjacent anode separator 40 and cathode separator 70 in the two power generation cells 11 . More specifically, the coolant channel 31 is formed by a space defined by the ribs 60 of the anode separator 40 and the ribs 90 of the cathode separator 70 .

As shown in FIG. 2, the plurality of gas channels 80 of the cathode separator 70 includes first gas channels 81 and second gas channels 82 . The first gas flow path 81 and the second gas flow path 82 are provided on opposite sides of each other with the rib 90 interposed therebetween. That is, the cathode separator 70 is alternately provided with the first gas flow paths 81 and the second gas flow paths 82 .

Hereinafter, the direction in which the gas flow path 80 extends will be referred to as the extending direction. Further, upstream and downstream in the flow direction of the reactant gas flowing through the gas passage 80 are simply referred to as upstream and downstream, respectively. The arrows in FIGS. 2 and 3 indicate the flow direction of the reaction gas from the upstream side to the downstream side.

(First narrowed portion 83A and second narrowed portion 83B)
As shown in FIGS. 2 and 3, the first gas flow path 81 and the second gas flow path 82 are provided with a first narrowed portion 83A and a second narrowed portion 83B, respectively, in which the cross-sectional area of the flow passage is partially reduced. is provided. The first narrowed portion 83A and the second narrowed portion 83B are provided at the same position in the extending direction, for example.

The first narrowed portion 83A and the second narrowed portion 83B in this embodiment have the same shape. Therefore, in the following description, the configuration of the first throttle portion 83A will be described, and the configuration of the second throttle portion 83B will be given the same reference numerals as the configuration of the first throttle portion 83A to avoid redundant explanation. omitted.

The first narrowed portion 83A extends in the extending direction. The first narrowed portion 83A is formed by making the width of a part of the first gas flow path 81 smaller than that of the other part. The depth of the first narrowed portion 83A is the same as the depth of other portions of the first gas flow path 81 .

As shown in FIG. 3, the first narrowed portion 83A includes a narrowed portion 84 having a constant flow passage cross-sectional area in the extending direction, an upstream gradually changing portion 85 connected to the upstream side of the narrowed portion 84, and a narrowed portion. and a downstream gradually changing portion 87 connected to the downstream side of the portion 84 . The upstream gradually changing portion 85 is provided at the upstream end of the first throttle portion 83A. The downstream gradually changing portion 87 is provided at the downstream end of the first throttle portion 83A.

The narrow portion 84 is a portion having the smallest width in the first narrowed portion 83A. Therefore, the channel cross-sectional area of the first narrowed portion 83A is minimized at the narrowed portion 84. As shown in FIG.
The flow passage cross-sectional area of the upstream gradually changing portion 85 is gradually decreased toward the downstream side. The upstream gradually changing portion 85 has two inclined side walls 86 extending obliquely with respect to the extending direction. The two inclined side walls 86 face each other in the width direction of the first gas flow path 81 . The two inclined side walls 86 extend toward each other toward the downstream side.

The downstream gradually changing portion 87 has a flow passage cross-sectional area that gradually increases toward the downstream side. The downstream gradually changing portion 87 has two inclined side walls 88 extending obliquely with respect to the extending direction. The two inclined side walls 88 face each other in the width direction of the first gas flow path 81 . The two inclined side walls 88 extend away from each other toward the downstream side.

(First communicating groove 91 and second communicating groove 92)
Each rib 90 is provided with a first communication groove 91 and a second communication groove 92 that communicate with each other. The first communication groove 91 communicates the first gas flow path 81 and the second gas flow path 82 . The second communication groove 92 communicates the second gas flow path 82 and the first gas flow path 81 . The first communication groove 91 and the second communication groove 92 in this embodiment have the same shape.

Each of the width and depth of the first communication groove 91 is smaller than the width and depth of the narrow portion 84 in the first narrowed portion 83A. Each of the width and depth of the second communication groove 92 is smaller than the width and depth of the narrow portion 84 in the second drawn portion 83B.

The first communication groove 91 has a first end 91a communicating with the upstream gradually changing portion 85 of the first throttle portion 83A and a second end 91b communicating with the downstream gradually changing portion 87 of the second throttle portion 83B. is doing. The first end 91a opens in the inclined side wall 86 of the upstream gradually changing portion 85 of the first throttle portion 83A. The second end 91b opens to the inclined side wall 88 of the downstream gradually changing portion 87 of the second throttle portion 83B.

The first communication groove 91 extends at an angle with respect to the extending direction so as to be located downstream the farther away from the first gas flow path 81 . That is, the first end 91a is provided upstream of the second end 91b in the extending direction.

The second communication groove 92 has a third end 92a communicating with the upstream gradually changing portion 85 of the second throttle portion 83B and a fourth end 92b communicating with the downstream gradually changing portion 87 of the first throttle portion 83A. is doing. The third end 92a opens in the inclined side wall 86 of the upstream gradually changing portion 85 of the second throttle portion 83B. The fourth end 92b opens in the inclined side wall 88 of the downstream gradually changing portion 87 of the first throttle portion 83A.

The second communication groove 92 extends at an angle with respect to the extending direction so as to be located downstream as it separates from the second gas flow path 82 . That is, the third end 92a is provided upstream of the fourth end 92b in the extending direction. The inclination angle with respect to the extending direction of the first communicating groove 91 and the inclination angle with respect to the extending direction of the second communicating groove 92 are the same.

As described above, each of the two ribs 90 adjacent to the first gas flow path 81 is provided with the first communication groove 91 and the second communication groove 92 . Therefore, two first communication grooves 91 communicate with the upstream gradually changing portion 85 of one first throttle portion 83A. Two second communication grooves 92 communicate with the downstream gradually changing portion 87 of one first throttle portion 83A.

A first communicating groove 91 and a second communicating groove 92 are provided in each of the two ribs 90 adjacent to the second gas flow path 82 . Therefore, two second communication grooves 92 communicate with the upstream gradually changing portion 85 of one second throttle portion 83B. Two first communication grooves 91 communicate with the downstream gradually changing portion 87 of one second throttle portion 83B.

The operation of this embodiment will be described.
(Action 1) In the cathode separator 70 , the first throttle portion 83</b>A of the first gas flow path 81 and the second gas flow path 82 communicate with each other through the first communication groove 91 . Therefore, part of the reaction gas flowing through the first narrowed portion 83A of the first gas flow path 81 flows toward the second gas flow path 82 via the first communicating groove 91 .

(Action 2) Since the flow channel cross-sectional area of the first communication groove 91 is smaller than the flow channel cross-sectional area of the narrow portion 84 of the first throttle portion 83A, the reaction gas flowing through the first gas flow channel 81 flows through the first communication groove. It becomes easier to flow to the first narrowed portion 83A than to 91.

(Action 3) The first communication groove 91 extends at an angle with respect to the extending direction so that the farther it is from the first gas flow path 81 , the more downstream it is positioned. Therefore, the reactant gas that has flowed into the first communication groove 91 flows smoothly downstream compared to the case where the first communication groove 91 extends in the direction orthogonal to the extending direction of the first gas flow path 81. easier.

(Action 4) Since the first end 91a of the first communicating groove 91 opens into the inclined side wall 86 of the first narrowed portion 83A, the projected area of the opening of the first end 91a in the extending direction can be increased. .

(Action 5) The second end 91b of the first communication groove 91 opens to the downstream gradually changing portion 87 of the second throttle portion 83B. Therefore, the generated water that has flowed into the second gas channel 82 through the first communication groove 91 is caused to flow into the second gas channel 82 by the reaction gas whose flow velocity is increased at the second throttle portion 83B of the second gas channel 82 . easier to be expelled from

(Action 6) Two first communication grooves 91 communicate with one first throttle portion 83A in the first gas flow path 81 . Therefore, part of the reaction gas flowing through the first throttle portion 83A flows through the two first communication grooves 91 toward the two second gas flow paths 82 adjacent to the first gas flow path 81 .

(Action 7) The second throttle portion 83B of the second gas flow path 82 and the first gas flow path 81 communicate with each other through the second communication groove 92 . Therefore, part of the reaction gas flowing through the second throttle portion 83B of the second gas flow path 82 flows toward the first gas flow path 81 via the second communicating groove 92 .

(Action 8) Part of the reaction gas flowing through the first throttle portion 83A of the first gas flow path 81 flows toward the second gas flow path 82 via the first communication groove 91, and the first communication groove 91 and flows toward the downstream side of the first gas flow path 81 via the second communication groove 92 . Similarly, part of the reaction gas flowing through the second throttle portion 83B of the second gas channel 82 flows toward the first gas channel 81 via the second communicating groove 92, It flows toward the downstream side of the second gas flow path 82 via the first communication groove 91 .

Effects of the present embodiment will be described.
(1) The cathode separator 70 has a first gas channel 81 and a second gas channel 82 and ribs 90 . A first narrowed portion 83A is provided in the first gas flow path 81 . The rib 90 is provided with a first communication groove 91 that communicates between the first narrowed portion 83A of the first gas flow path 81 and the second gas flow path 82 . A first end 91 a of the first communication groove 91 communicating with the first gas flow path 81 is provided upstream of the second end 91 b in the extending direction of the gas flow path 80 .

According to such a configuration, since the above-described effect 1 is achieved, it is possible to suppress an increase in the pressure loss of the reaction gas in the first throttle portion 83A.
(2) The channel cross-sectional area of the first communication groove 91 is smaller than the channel cross-sectional area of the narrow portion 84 of the first throttle portion 83A.

According to such a configuration, since the above-described effect 2 is achieved, it is possible to suppress an increase in the pressure loss of the reaction gas in the first throttle portion 83A while ensuring the flow rate of the reaction gas passing through the first throttle portion 83A.

(3) The first communication groove 91 extends at an angle with respect to the extending direction so that the farther away from the first gas flow path 81, the more downstream it is positioned.
With such a configuration, since the above-described effect 3 is achieved, it is possible to suppress an increase in the pressure loss of the reaction gas in the first throttle portion 83A.

(4) The first end 91a of the first communication groove 91 opens to the inclined side wall 86 of the first narrowed portion 83A.
With such a configuration, the reaction gas can easily flow into the first communication groove 91 because the above-described effect 4 can be achieved. Therefore, it is possible to suppress an increase in the pressure loss of the reaction gas in the first narrowed portion 83A.

(5) The first end 91a and the second end 91b of the first communication groove 91 are opened to the upstream gradually changing portion 85 of the first throttle portion 83A and the downstream gradually changing portion 87 of the second throttle portion 83B, respectively. there is
With such a configuration, the above-described function 5 can be achieved, so that the discharge of generated water can be improved.

(6) Each of the two ribs 90 extending between one first gas flow path 81 and each of the two second gas flow paths 82 is provided with a first communication groove 91 .
According to such a configuration, since the above-described effect 6 is exhibited, it is possible to suppress an increase in the pressure loss of the reaction gas in the first throttle portion 83A.

(7) The rib 90 is provided with a second communication groove 92 that communicates the second narrowed portion 83B of the second gas flow path 82 and the first gas flow path 81 . The third end 92a of the second communication groove 92 is provided upstream of the fourth end 92b in the extending direction.

According to such a configuration, in order to achieve the above-described effect 7, the pressure loss of the reaction gas is reduced not only in the first narrowed portion 83A of the first gas flow path 81 but also in the second narrowed portion 83B of the second gas flow path 82. Increase can be suppressed.

(8) One rib 90 is provided with a first communication groove 91 and a second communication groove 92 that communicate with each other.
According to such a configuration, part of the reactant gas is exchanged between the first gas flow path 81 and the second gas flow path 82 in order to achieve the effect 8 described above. Therefore, the pressure difference between the first narrowed portion 83A of the first gas flow path 81 and the second narrowed portion 83B of the second gas flow path 82, and thus the pressure difference between the plurality of gas flow paths 80 can be reduced. can.

<Change example>
This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

In addition, in the first to sixth modified examples shown in FIGS. 4 to 9 below, the same reference numerals are assigned to the configurations corresponding to the above-described embodiments, thereby omitting redundant description.
・As shown in FIG. 4, one first communication groove 91 may be provided for one first throttle portion 83A, and one second communication groove 92 may be provided for one second throttle portion 83B. can. In this case, the ribs 90 provided with the first communication grooves 91 and the ribs 90 provided with the second communication grooves 92 are alternately provided on the cathode separator 70 . According to such a configuration, the effects (1) to (5) and effect (7) described above can be achieved.

- As shown in FIG. 5, the second communication groove 92 may be omitted from the second gas flow path 82, and two first communication grooves 91 may be provided for one first throttle portion 83A. In this case, the cathode separator 70 is provided with one first communication groove 91 for each rib 90 . With such a configuration, the effects (1) to (6) described above can be achieved.

- As shown in FIG. 6, the second communication groove 92 may be omitted from the second gas flow path 82, and one first communication groove 91 may be provided for one first throttle portion 83A. In this case, the ribs 90 provided with the first communication grooves 91 and the ribs 90 not provided with the first communication grooves 91 are alternately provided on the cathode separator 70 . With such a configuration, the effects (1) to (5) described above can be achieved.

- As shown in FIG. 7 , the second throttle portion 83B and the second communication groove 92 can be omitted from the second gas flow path 82 . With such a configuration, the effects (1) to (4) described above can be achieved.

- As shown in FIG. 8, the upstream gradual change portion 85 and the downstream gradual change portion 87 can be omitted from the first throttle portion 83A and the second throttle portion 83B. In this case, the first communication groove 91 and the second communication groove 92 should just communicate the narrow portions 84 with each other. With such a configuration, the effects (1) to (3) described above can be achieved.

- As shown in FIG. 9, the second communication groove 92 may be omitted from the second gas flow path 82, and the first communication groove 91 extending in the width direction orthogonal to the extending direction of the gas flow path 80 may be provided. . In this case, the first end 91a is provided at a position aligned with the second end 91b in the extending direction. It is preferable that the first communication groove 91 communicates between the narrow portions 84 . According to such a configuration, the effects (1) and (2) described above can be achieved.

- The inclined side walls 86 and 88 may be provided only on one side in the width direction of the gas flow path 80 .
- The first gas flow path 81 and the second gas flow path 82 may have different shapes.

- The first communication groove 91 and the second communication groove 92 may have different shapes.
- The communication grooves 91 and 92 do not have to extend linearly. The first communication groove 91 may be curved, for example, such that the first end 91a is located upstream of the second end 91b. Similarly, the second communication groove 92 may be curved such that the third end 92a is located upstream of the fourth end 92b, for example.

Each of the communicating grooves 91 and 92 may have the same depth as the narrow portion 84 as long as it has a width smaller than that of the narrow portion 84 .
Each of the communicating grooves 91 and 92 may have the same width as the narrow portion 84 as long as it has a depth smaller than the depth of the narrow portion 84 .

- The channel cross-sectional area of each of the communication grooves 91 and 92 may be the same as the channel cross-sectional area of the narrow portion 84 .
- The first narrowed portion 83A and the second narrowed portion 83B may be provided at different positions in the extending direction.

- In the above embodiment, an example in which the present invention is applied to the cathode separator 70 has been described, but the present invention can also be applied to the anode separator 40 .

DESCRIPTION OF SYMBOLS 10... Cell stack 11... Power generation cell 20... Membrane electrode gas diffusion layer assembly 21... Membrane electrode assembly 22... Electrolyte layer 23... Anode electrode layer 24... Cathode electrode layer 25... Anode gas diffusion layer 26... Cathode gas diffusion layer 30 DESCRIPTION OF SYMBOLS Separator 31 Coolant flow path 40 Anode separator 50 Gas flow path 60 Rib 70 Cathode separator 80 Gas flow path 81 First gas flow path 82 Second gas flow path 83A First narrowed portion 83B ...Second throttle section 84 ... Narrow section 85 ... Gradually changing upstream section 86 Gradually changing portion on the upstream side 86 Gradual changing section on the downstream side 88 ... Gradually changing section on the downstream side 88 ... Inclined side wall 90 ... Rib 91 ... First communication groove 91a ... First end 91b ... Second end 92... Second communicating groove 92a... Third end 92b... Fourth end

Claims (8)

a plurality of gas flow passages extending in parallel with each other at intervals and through which reaction gases flow; and ribs extending along the gas flow passages between the gas flow passages adjacent to each other; A fuel cell separator in which a gas channel is provided with a constricted portion with a partially reduced cross-sectional area of the channel,
When upstream and downstream in the direction of flow of the reactant gas flowing through the gas channel are simply referred to as upstream and downstream, respectively,
The plurality of gas flow paths includes a first gas flow path provided with the constricted portion and a second gas flow path adjacent to the first gas flow path,
The rib is provided with a communication groove that communicates the narrowed portion of the first gas flow path and the second gas flow path,
The first end of the communication groove that communicates with the first gas flow path is aligned with the second end of the communication groove that communicates with the second gas flow path in the extending direction of the gas flow path, or provided at a position upstream of the second end,
Fuel cell separator. The channel cross-sectional area of the communicating groove is smaller than the channel cross-sectional area of the constricted portion,
The fuel cell separator according to claim 1. The communication groove extends at an angle with respect to the extending direction so as to be located downstream as the distance from the first gas flow path increases.
3. The fuel cell separator according to claim 1 or 2. An upstream gradually changing portion having an inclined side wall extending at an angle with respect to the extending direction and having a flow passage cross-sectional area that gradually decreases toward the downstream side is provided at an upstream end of the narrowed portion. the first end is open to the sloped sidewall;
The fuel cell separator according to any one of claims 1 to 3. The second gas flow path is provided with the narrowed portion,
At the upstream end of the constricted portion in the first gas flow path, an inclined side wall extending at an angle with respect to the extending direction is provided, and the cross-sectional area of the flow path gradually decreases toward the downstream side. There is a change part,
At the downstream end of the constricted portion in the second gas flow path, there is an inclined side wall that extends obliquely with respect to the extending direction, and the flow path cross-sectional area gradually increases toward the downstream side. There is a change part,
The first end and the second end are open to the upstream gradually changing section and the downstream gradually changing section, respectively.
The fuel cell separator according to any one of claims 1 to 4. The gas flow path includes two second gas flow paths located on opposite sides of the first gas flow path,
said ribs including two said ribs extending between said first gas flow path and each of said two second gas flow paths;
Each of the two ribs is provided with the communication groove,
The fuel cell separator according to any one of claims 1 to 5. When the communication groove is the first communication groove,
The second gas flow path is provided with the narrowed portion,
The rib is provided with a second communication groove that communicates the narrowed portion of the second gas flow path and the first gas flow path,
A third end of the second communication groove communicating with the second gas flow path is aligned with a fourth end of the second communication groove communicating with the first gas flow path in the extending direction, or provided at a position upstream of the fourth end,
The fuel cell separator according to any one of claims 1 to 6. The one rib is provided with the first communication groove and the second communication groove communicating with each other,
The fuel cell separator according to claim 7.

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