JP2001006695A - Separator of fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator of fuel cell capable of preventing hydrogen gas or oxygen gas from leaking at a groove provided in the neighbourhood of a through hole. SOLUTION: Separators 41 to be used in a plurality of fuel cells (40) stacked are made in plate form for partitioning the fuel cells (40) and their two sides are sealed by gaskets. Each separator 41 is furnished across the thickness with through holes 41a-41d as a flow passage for hydrogen gas or oxygen gas, and at the side face with a groove 41e in communication with the through holes 41a-41d, and a pipe 51 for securing the gasket contacting pressure to the separators 41 is installed at the end of the groove 41e in the neighbourhood of the through holes 41a-41d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separator used for a fuel cell.

[0002]

2. Description of the Related Art In recent years, fuel cells have been developed for the purpose of application to batteries of motors for electric vehicles. In a fuel cell, after hydrogen as a negative electrode active material is brought into contact with a catalyst such as platinum (platinum) to dissociate it into electrons and protons, water is obtained by reacting the protons with oxygen as a positive electrode active material. Based on reaction mechanism.
That is, in the fuel cell, an electron emitted from hydrogen moves on the negative electrode side and reaches the positive electrode side to induce an electromotive force.

[0003] Based on such a principle, a fuel cell is
Since the chemical energy change can be directly converted into electric energy, the energy conversion efficiency is extremely high as compared with other power generation methods. Therefore, the fuel cell has less energy loss than an internal combustion engine based on the Carnot cycle, and is useful as a battery of a motor for an electric vehicle, which is an alternative to the internal combustion engine.

In a fuel cell, exhaust gas is mainly water vapor and does not emit harmful gases such as nitrogen compounds, hydrocarbons or hydrogen monoxide unlike an internal combustion engine. Practical use of electric vehicles using batteries as batteries has been desired.

FIG. 2 is a diagram showing an example of a fuel cell stack in which a fuel cell is housed when the fuel cell is applied to an electric vehicle. The fuel cell stack 4 has a configuration in which a plurality of fuel cells 40 are stacked in series to obtain a required voltage, and is sandwiched between end plates 4A and 4B by bolts B and nuts N.

[0006] As shown in FIG.
One separator 41 and a second separator 42, an ion exchange membrane 43 interposed between these separators 41, 42, an ion exchange membrane 43 and the first separator 41.
And a first gasket 46 and a second gasket 47 interposed between the first gasket 46 and the second separator 42.

The first and fourth separators 41 and 42 are provided with first through fourth bolts B for bolting.
Through holes 41 a to 41 d and 42 a to 42 d are formed, and the through holes 41 a to 41 d and 42 a to 42 d are shared as a supply path for supplying hydrogen gas or oxygen gas to the fuel cell 40. In addition, each separator 4
On one side 41A, 42A and on the other side (not shown) of the fuel cells 1 and 42, grooves 41e and 42e for supplying oxygen gas or hydrogen gas to each fuel cell 40 are provided. In the battery 40, the same separator is shared between adjacent fuel cells 40.

A groove 41 on one side 41A of the separator 41
e communicates with the first and second through-holes 41a and 41b and is not shown in FIG.
And the fourth through holes 41c and 41d. For example, an oxygen gas is supplied to the groove 41e on the one surface 41A, and a hydrogen gas is supplied to the groove 41e on the other surface. By supplying oxygen gas and hydrogen gas to each member of each fuel cell 40 from the groove 41e, the fuel cell 40 functions as a battery in a region sandwiched between the separators 41 and 42.

Here, the separators 41 and 42, when in a stacked state, have first and second gaskets 46 and 47.
Thus, the body is sandwiched between the two sides at a predetermined surface pressure. FIG. 12 is a diagram showing, for example, a state in which the respective members are stacked in a stack state. When focusing on the groove 42e of the separator 42, in the groove 42e near the through hole 42a, the second gasket 47 And the nut N may be loosened slightly due to the pinching force. Then, accordingly, the ion exchange membrane 43 and the first gasket 46
Is slightly loosened, and a minute gap S is generated between the first gasket 46 and the other surface 41B of the first separator 41.

Therefore, the adhesion between the first gasket 46 and the first separator 41 may be impaired, and the first gasket 46 may not be able to secure a desired surface pressure on the first separator 41. As a result, oxygen gas enters the groove on the other side 41B of the first separator 41 from the minute gap S, and hydrogen gas enters the minute gap S from the minute gap S.
Leaking into the first through-hole 41a from above, which may hinder the operation of the fuel cell 40.

[0011] In addition to the above case, the minute gap S is
Each of the separators 41 in the second through holes 41b and 42b,
42 between the other side 41B, 42B and the gasket 46 in contact therewith, or the third and fourth through holes 41c,
Each of the separators 41, 4 in 42c, 41d, 42d
1 side 41A, 42A and gasket 4 in contact with it
7 also occurs.

[0012]

DISCLOSURE OF THE INVENTION The present invention has been conceived in view of the above circumstances, and has been developed for a fuel cell separator capable of preventing hydrogen gas or oxygen gas from leaking in a groove near a through hole. The task is to provide.

In order to solve the above problems, the present invention takes the following technical means. According to a first aspect of the present invention, there is provided a separator which is applied to a plurality of stacked fuel cells, is formed in a plate shape for partitioning each fuel cell, and is sealed on both sides by a sealing member. The separator has a through hole as a flow path for hydrogen gas or oxygen gas formed in the thickness direction, a groove communicating with the through hole is formed on the side surface, and at an end of the groove near the through hole,
A fuel cell separator is provided, wherein a surface pressure securing member for securing a surface pressure of the sealing member to the separator is provided.

According to the present invention, since the surface pressure securing member is disposed at the end of the groove near the through hole, the surface pressure of the sealing member against the separator near the through hole can be sufficiently secured. Therefore, leakage of hydrogen gas or oxygen gas between the sealing member and the separator at the end of the groove can be prevented.

According to a preferred embodiment, specifically, the surface pressure securing member may be a hollow body having a thickness substantially equal to the depth of the groove, or a thickness substantially equal to the depth of the groove. It may be a porous body having air permeability. Alternatively, a stepped recess serving as a gas flow path may be formed along the groove at the end of the groove near the through hole, and the surface pressure securing member may be disposed above the stepped recess. By arranging these surface pressure securing members in the groove, the sealing member can secure a uniform surface pressure by the thickness of the surface pressure securing member arranged in the groove, and eliminate slack in the groove. And good adhesion to the separator can be maintained.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG.
1 is a schematic configuration diagram showing an example of a fuel cell system to which a fuel cell having a separator according to the present invention is applied. The fuel cell system 1 includes a reformer 2 for reforming ethanol to obtain a hydrogen-rich fuel gas, a reformer 3 for converting carbon monoxide gas contained in the fuel gas into carbon dioxide gas, A fuel cell 40 for obtaining a desired electromotive force by reacting a gas and an oxygen gas is provided with a fuel cell stack 4 in which the fuel cells 40 are assembled in series.

The reformer 2 reforms ethanol into a hydrogen-rich fuel gas by, for example, a steam reforming method. The reformer 2 includes a reformer 20 filled with a catalyst for reforming ethanol and a reformer 20. And a heater 21 for heating the inside of the container 20 to a temperature suitable for reforming ethanol. The ethanol and steam supplied to the reformer 20 and heated by the heater 21 react by the action of a catalyst to generate carbon monoxide and hydrogen. When a boiler is used as the heater 21, part of the raw material ethanol and hydrogen gas not consumed in the fuel cell stack 4 are used as boiler fuel.

The shift unit 3 selectively oxidizes only carbon monoxide of the carbon monoxide and hydrogen supplied from the reforming unit 2 to shift to carbon dioxide. That is, the mixed gas containing a trace amount of carbon monoxide obtained in the reformer 2 is supplied to the shift converter 3 together with the air,
The carbon monoxide gas is air-oxidized (converted) to carbon dioxide gas by the action of a catalyst (for example, a photocatalyst) and supplied to the fuel cell stack 4.

FIG. 2 is a perspective view of the fuel cell stack 4 shown in FIG. FIG. 3 is an exploded perspective view of the fuel cell 40, and FIG. 4 is a longitudinal sectional view of the fuel cell 40.

The fuel cell stack 4 has a configuration in which a plurality of fuel cells 40 are stacked in series so that adjacent fuel cells 40 share the same separator 41, 42, and end plates 4A, 4B Between the bolts B and the nuts N. Four supply holes 4 for supplying hydrogen gas or oxygen gas are provided on one end plate 4A side and the other end plate 4B side.
Aa, 4Ab, 4Ac, and 4Ad are formed, and the supply hole 4A is formed.
a to 4Ad communicate with through holes (not shown) through which bolts B are inserted inside the end plates 4A and 4B,
The through-hole is shared as a supply path for supplying hydrogen gas or oxygen gas to each fuel cell 40.

As shown in FIG. 3, the fuel cell 40 has a first
Separator 41 and second separator 42, an ion exchange membrane 43 interposed between the separators 41 and 42, and an ion exchange membrane 43 interposed between the first separator 41 and the second separator 42. A first gasket 46 and a second gasket as sealing members arranged so as to surround the negative electrode current collector 44 and the positive electrode current collector 45, and the outer frames of the negative electrode current collector 44 and the positive electrode current collector 45. 47 are provided.

Each of the separators 41 and 42 is entirely made of a metal conductor such as titanium and is formed in a plate shape. The separators 41 and 42 are provided to secure a region functioning as a battery between them, and are used when supplying hydrogen gas or oxygen gas. Therefore, the separators 41 and 42 have excellent heat resistance and mechanical strength. Formed by high materials. For example, as the material of the separators 41 and 42, a stainless steel, a titanium alloy, or the like may be used in addition to the titanium.

At each of the four corners of the separators 41 and 42, first to fourth through holes 41a to 41d and 42a to 42d of a substantially square shape penetrating in the thickness direction are formed. Note that the ion exchange membrane 43, the first gasket 46, and the second gasket 47 also have first to fourth through holes 41a to 41a of the separators 41 and 42 at the four corners, respectively.
1d, 42a to 42d, four substantially square through holes 43a to 43d, 46a to 46d, 47a to 47, respectively.
d is formed. When the fuel cell 40 is in a stack state, as shown in FIG. 4, the through holes provided in each member are configured to be coaxially connected to each other (hereinafter, the through holes provided in each member described above). Communication hole 4
a to 4d. ).

One side 41A of each separator 41, 42,
A groove as a flow path for hydrogen gas or oxygen gas is formed in 42A and the other surface sides 41B and 42B. That is, the first surface 41A of the separator 41 communicates with the first through hole 41a and the second through hole 41b so as to connect the first through hole 41a and the second through hole 41b.
A plurality of grooves 41e formed by etching, for example, by photo etching or the like are formed so as not to cross each other. Also, one side 42A of the separator 42
Are formed with a plurality of grooves 42e communicating with each other so as to connect the first through hole 42a and the second through hole 42b.
On the other hand, the other side 41B, 42B of each separator 41, 42
Also, a groove similar to the first surface side 41A, 42A is formed in the third through hole 41c, 42c or the fourth groove.
They communicate with the through holes 41d and 42d, respectively.

One side 41 of each of the separators 41 and 42
The grooves 41e formed in the A and 42A serve as flow paths for oxygen gas, and the grooves formed in the other side 41B and 42B serve as flow paths for hydrogen gas. Therefore, this fuel cell 4
At 0, one separator can be shared between adjacent fuel cells 40.

On one side 41A and the other side 41B of the separator 41, the outer surface excluding the groove 41e and each side surface of the separator 41 are made of a metal material for protecting the surface of titanium forming the separator 41, for example, platinum. Plating is applied. The bottom surface and the inner wall surface of the groove 41e are coated with a fluororesin or the like. The above-mentioned surface treatment is similarly applied to one side 42A and the other side 42B of the separator 42 and to each side.

The ion exchange membrane 43 has proton conductivity and selectively allows hydrogen ions to pass therethrough. A negative electrode catalyst part 43A and a positive electrode catalyst part 43B are formed on both surfaces of the ion exchange membrane 43, respectively.

The anode catalyst part 43A is a porous layer made of catalyst particles having platinum supported on the surface of carbon particles, for example, and is capable of passing hydrogen molecules and hydrogen ions. In the anode catalyst part 43A, the supplied hydrogen gas is dissociated into hydrogen ions and electrons.

On the other hand, the positive electrode catalyst portion 43B is a porous layer composed of catalyst particles in which platinum and rhodium coexist and are supported on the surface of carbon particles, for example, so that oxygen molecules can pass therethrough. In the positive electrode catalyst portion 43B, oxygen gas reacts with hydrogen ions and electrons to generate water.

The negative electrode current collector 44 is formed in a substantially cross shape as a porous body of, for example, a carbon-based material, so that electrons dissociated from hydrogen gas in the negative electrode catalyst portion 43A can be collected and taken out of the fuel cell 40. Further, the hydrogen gas is passed so that the supplied hydrogen gas reaches the anode catalyst part 43A.

On the other hand, the positive electrode current collector 45 is
In the same manner as described above, a porous body is formed in a substantially cross shape by a carbon-based material, for example, so that electrons can be received from the outside, and the electrons can be supplied to the positive electrode catalyst portion 43B. The oxygen gas is passed to reach the part 43B.

The first and second gaskets 46, 47 are
The ion exchange membrane 43 and the first or second separator 41,
42, that is, to enhance the sealing state between adjacent separators. The first and second gaskets 46 and 47 have a shape in which substantially cross-shaped openings 46A and 47A larger than the area of the current collectors 44 and 45 are provided in the center thereof, and when the fuel cell 40 is configured. , Gaskets 46, 47 surround the current collectors 44, 45. In FIG. 4, C is a bolt B
Indicates a tube to be inserted.

The feature of this embodiment is that grooves 41e, 42e formed on one side 41A, 42A of each separator 41, 42 and on the other side 41B, 42B.
B, the through holes 41a to 41
d, 42a to 42d, the separators 41, 42 of the gaskets 46, 47 are provided at the ends of the grooves 41e, 42e in the vicinity.
The point is that a hollow body (pipe) as a surface pressure securing member for securing a surface pressure with respect to is provided. With this surface pressure securing member, it is possible to uniformly secure the surface pressure of each gasket 46, 47 on each of the separators 41, 42 at the ends of the grooves 41e, 42e near the through holes 41a to 41d, 42a to 42d. Thus, leakage of hydrogen gas or oxygen gas can be prevented.

The details will be described below. FIG. 5 shows the configuration of the first separator 41 near the first through-hole 41a on one side 4
It is the perspective view seen from 1A. The configuration shown in FIG.
Configuration near the second through-hole 41b on one side 41A of the first separator 41, the other side 4 of the first separator 41
The configuration in the vicinity of the third and fourth through holes 41c and 41d in 1B is the same. The second separator 42 has the same configuration.

According to FIG. 3, a plurality of pipes 51 as surface pressure securing members are arranged at the end of each groove 41e near the first through hole 41a of the first separator 41. The pipe 51 is adhered to the bottom surface of the groove 41e along the inside of the groove 41e such that one end thereof is substantially flush with the inner surface 41f of the first through hole 41a.

The pipe 51 is made of a metal such as stainless steel or titanium, and is formed in a substantially cylindrical shape having a hollow structure and a predetermined length. The outer diameter of the pipe 51 is the groove 41e.
For example, when the depth of the groove 41e is 80 μm, the outer diameter of the pipe is set to a tolerance of 80 ± 10 μm. Therefore, when the pipe 51 is disposed in the groove 41e, as shown in FIG. 6, the surface 41A of the first separator 41 excluding the groove 41e and the top of the peripheral surface of the pipe 51 become substantially flush. Therefore, in the vicinity of the through hole 41a, each gasket 46, 47 can sufficiently adhere to one surface 41A, 42A and the other surface 41B, 42B of each separator 41, 42. Therefore, leakage of hydrogen gas or oxygen gas between each gasket 46, 47 and separator 41, 42 can be prevented.

As described above, the groove 4 near each through hole 41a is formed.
By disposing a pipe 51 whose outer diameter is substantially equal to the depth of the groove 41e at the end of 1e, each separator 4 of each of the gaskets 46 and 47 is placed in a stacked state.
The surface pressure on the first and second members 42 can be ensured favorably.
Therefore, also in the groove near each through hole 41a, the separators 41 and 42 and the gaskets 46 and 47 are reliably sealed, the adhesion of each is increased, and oxygen gas is supplied to the grooves on the other side 41B and 42B. It is possible to prevent the gas from entering and the hydrogen gas from leaking into the first or second communication holes 4a and 4b, and to stably operate the fuel cell. Further, since the pipe 51 has a hollow structure, the flow of the hydrogen gas or the oxygen gas is hardly obstructed in the groove 41e, and the hydrogen gas or the oxygen gas is stably supplied to the groove 41e of the separator 41.

The pipe 51 disposed in the groove 41e
Is the surface of one side 41A of the separator 41 and the pipe 5
The number and shape of the grooves 41e may be changed in accordance with the size of the cross section of the groove 41e, as long as the top of the peripheral surface 1 is substantially flush. For example, one groove 41e
The number of the pipes 51 is not limited to two, and a different number of pipes 51 may be provided, and a plurality of pipes 51 may be stacked as shown in FIG.
In addition, as shown in FIG. 8, a hollow body 51 having a substantially prismatic shape may be arranged instead of the pipe.

As another embodiment which replaces the hollow body 51, as shown in FIG. 9, a porous body 52 having air permeability is arranged at the end of the groove 41e near each through hole 41a. You may. As the porous body 52,
An open-celled foam made of metal or ceramic having continuously connected cells, a sintered body obtained by heating and melting a metal powder without melting it is preferably used.
The porous body 52 is formed in a substantially rectangular shape according to the shape of the groove 41e, and is formed such that its thickness is substantially equal to the depth of the groove 41e. Also in this configuration, the same operation and effect as those of the above-described pipe 51 can be obtained.

Further, a groove 41e near each through hole 41a.
The shape of the end of the groove 41 is as shown in FIGS.
e, a stepped concave portion 53 is formed along the groove portion 41e, and a plate body 5 as a surface pressure securing member is formed on an upper stage of the stepped concave portion 53.
4 may be arranged. The width of the lower step of the stepped recess 53 is smaller than that of the plate 54, and the plate 54 is bonded to the step 55.

As the material of the plate 54, a material that blocks hydrogen gas or oxygen gas, for example, metal, plastic or the like is sufficient. Preferably, the above-mentioned hollow body or open-cell foam is used for the purpose of improving the gas flow rate. Further, the thickness of the plate 54 is formed to be substantially equal to the depth of the groove 41e.

As described above, since the flow path is formed by the stepped recess 53, hydrogen gas or oxygen gas is supplied to the stepped recess 5.
3 can be supplied to the groove 41 e of the separator 41. Moreover, the gasket 4 is formed by the plate 54.
The surface pressure on the separators 41 and 42 of 6, 47 can be sufficiently ensured.

As described above, in the fuel cell stack 4, if hydrogen gas is supplied from one or both of the third and fourth communication holes 4c and d with the other end plate 4B side as an inlet, Hydrogen gas is passed through the grooves on the other surfaces 41B, 42B of the separators 41, 42.
Then, excess hydrogen gas is discharged from one end plate 4A side, and this hydrogen gas is supplied as fuel for the heater 21 of the reformer 2 as shown in FIG.

When oxygen gas is supplied from one or both of the first and second communication holes 4a and 4b, the oxygen gas is passed through the grooves 41e on the surfaces 41A and 42A of all the separators 41 and 42. You. The oxygen gas is usually supplied in an air state.

In each fuel cell 40, for example, part of the hydrogen gas passing through the third communication hole 4c is
1 is supplied to the groove formed on the other side 41B. In this case, the separators 41 and 42 are provided by the surface pressure securing members.
And the gaskets 46 and 47 are sealed well, and hydrogen gas does not enter the grooves 41e of the surfaces 41A and 42A of the separators 41 and 42.

The hydrogen gas supplied to the groove passes through the negative electrode current collector 44 and is dissociated into hydrogen ions and electrons in the negative electrode catalyst 43A. The electrons generated during this reaction are collected by the negative electrode current collector 44, and the electrons are supplied to the positive electrode current collector 45 of the adjacent fuel cell 40 sharing the separator 41 via the separator 41.

On the other hand, hydrogen ions generated during the reaction in the anode catalyst section 43A pass through the ion exchange membrane 43 and move to the cathode catalyst section 43B. Electrons are further supplied to the cathode catalyst unit 43B from the anode current collector 44 of the adjacent fuel cell 40 sharing the separator 41.

A part of the air (oxygen gas) passing through the first or second communication holes 4a and 4b is formed in the groove 41e formed on one surface 41A of the separator 41 and the positive electrode current collector 45.
Is supplied via In this case, the space between the separators 41 and 42 and the gaskets 46 and 47 is satisfactorily sealed by the surface pressure securing member, and oxygen gas is supplied to the separators 41 and 4.
2 does not enter the groove on the other surface 41B, 42B side. As described above, in the cathode catalyst unit 43B to which the oxygen gas, the electrons, and the hydrogen ions have been supplied, they react to generate water.

As described above, in the fuel cell stack 4, 1
The electrons collected in the negative electrode current collector 44 of the fuel cell 40 of
It is supplied to the positive electrode current collector 45 of the adjacent fuel cell 40. The electrons collected by the negative electrode current collector 44 of the fuel cell 40 located at the most downstream in the flow direction of the electrons flow via an external circuit to the positive electrode of the fuel cell 40 located at the most upstream position in the flow direction of the electrons. The power is supplied to the current collector 45. That is, in the fuel cell stack 4, electrons flow in a certain direction as a whole, and electrons are circulated from the most downstream fuel cell 40 to the most upstream fuel cell 40 via an external circuit. . Then, energy is taken out and used in an external circuit.

Of course, the scope of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the invention.

[0052]

As described above, according to the present invention, since the surface pressure securing member is disposed at the end of the groove near the through hole, the surface pressure of the sealing member against the separator near the through hole is increased. And the leakage of hydrogen gas or oxygen gas between the sealing member and the separator can be prevented. Therefore, the fuel cell can be operated stably, and a highly reliable fuel cell can be provided.

Further, since the thickness of the surface pressure securing member is substantially equal to the depth of the groove, the sealing member is arranged on the surface provided in the groove by disposing these surface pressure securing members in the groove. The surface pressure can be uniformly secured by the thickness of the pressure securing member, the slack in the groove can be eliminated, and the adhesion to the separator can be maintained well.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fuel cell system to which a fuel cell separator according to the present invention is applied.

FIG. 2 is a perspective view of the fuel cell stack shown in FIG.

FIG. 3 is an exploded perspective view of the fuel cell.

FIG. 4 is a longitudinal sectional view of a fuel cell.

FIG. 5 is a perspective view showing a configuration near a through hole of a separator.

FIG. 6 is a side view when the surface pressure securing member is arranged in the groove.

FIG. 7 is a view showing a modification of the surface pressure securing member.

FIG. 8 is a view showing another modification of the surface pressure securing member.

FIG. 9 is a view showing another modification of the surface pressure securing member.

FIG. 10 is a view showing another modification of the surface pressure securing member.

FIG. 11 is a view showing another modification of the surface pressure securing member.

FIG. 12 is a vertical sectional view of a main part of a fuel cell.

[Explanation of symbols]

 Reference Signs List 40 fuel cell 41, 42 separator 41e, 42e groove 46, 47 gasket 41a to 41d through hole 51 pipe 52 porous body 53 stepped recess 54 plate

Claims (4)

[Claims] The invention is applied to a plurality of stacked fuel cells,
A separator formed in a plate shape to partition each of the fuel cells, and both surfaces of which are sealed by a sealing member, wherein the separator serves as a flow path for hydrogen gas or oxygen gas in a thickness direction. A through-hole is formed, and a groove communicating with the through-hole is formed on a side surface, and a surface pressure for securing a surface pressure of the sealing member against the separator is provided at an end of the groove near the through-hole. A separator for a fuel cell, wherein a securing member is disposed. 2. The fuel cell separator according to claim 1, wherein the surface pressure securing member is a hollow body having a thickness substantially equal to the depth of the groove. 3. The surface pressure securing member is a porous body having air permeability, the thickness of which is substantially equal to the depth of the groove.
The fuel cell separator according to claim 1. 4. A stepped recess serving as a flow path of the gas is formed along the groove at an end of the groove near the through hole, and the surface pressure securing member is disposed above the stepped recess. The fuel cell separator according to claim 1, wherein: