JP2003031236A - Separator for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in production cost of a fuel cell and a fuel cell stack by installing in integral structure a surface pressure ensuring portion for ensuring the surface pressure of a gasket in the tip part of each gas passage of a separator for the fuel cell, and eliminating the fitting work of a surface pressure ensuring member to each gas passage groove of the separator in order to ensure the surface pressure in the surface pressure ensuring portion. SOLUTION: This separator 20 has a plurality of gas passage grooves 22a-22d through which reaction gas is passed on one side. Many narrow groove portions 24a each having the width narrower than that of the gas passage grooves 22a-22d are installed in the gas passage grooves 22a-22d and a communication part of a gas inflow passage 23 and a gas outflow passage, and the surface pressure ensuring portion 24 is used for ensuring the surface pressure.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell separator.

[0002]

2. Description of the Related Art JP-A-2001
As disclosed in Japanese Patent Laid-Open No. 6695, a solid electrolyte membrane having electrodes on each side surface, and a pair of separators disposed on each side surface side of the solid electrolyte membrane via a sealing member are used. There is a fuel cell. In the fuel cell of the type, on one side surface side of the solid electrolyte membrane, a reaction chamber into which the fuel gas flows is formed by one separator, and on the other side surface side of the solid electrolyte membrane, the oxidant gas by the other separator. Is formed, and electric power is generated by a redox reaction occurring in both reaction chambers.

In addition, in the separator constituting the fuel cell of the type, smooth flow of each gas introduced into the reaction chamber and contact efficiency between each gas and the solid electrolyte membrane while flowing in the reaction chamber. In order to increase the temperature, a plurality of flow grooves through which the fuel gas or the oxidant gas flows are formed in parallel on one side surface of the separator.

FIG. 1 shows a fuel cell stack formed by polymerizing a large number of the fuel cells as one unit.
Shows a vertical cross section of the fuel cell which is one unit, and FIG. 3 shows an exploded perspective view of the fuel cell. The fuel cell 10 comprises a solid electrolyte membrane 11, electrodes 12 and 13 located on each side surface of the solid electrolyte membrane 11, and gaskets (sealing members) 14 and 15 fitted to the outer peripheries of the electrodes 12 and 13. It is composed of the separators 16 and 17 which are disposed through.

Solid electrolyte membrane 11, gaskets 14, 1
5, each separator 16, 17, in the four corners,
Square through holes 11a to 11d, 14a to 14d, 15a
-15d, 16a-16d, 17a-17d are formed. Each of the through holes is a mounting bolt 18a to 18d when the fuel cells are polymerized with each other and assembled into a fuel cell stack.
And an inflow path and an outflow path for the fuel gas, and an inflow path and an outflow path for the oxidant gas. For example, among each through hole, each through hole of the system a forms an inflow passage of hydrogen gas which is a fuel gas, and each through hole of the system b forms an outflow passage of hydrogen gas which is a fuel gas. Further, among the through holes, each of the c-system through-holes forms an inflow path for air that is an oxidant gas, and each d-system through-hole forms an outflow path for air that is an oxidant gas.

Further, in each of the separators 16 and 17, a plurality of gas flow grooves 16e and 17e are provided on one side surface of these separators.
Are formed in parallel, and a plurality of gas flow grooves 16f, 17f are formed in parallel on the other side surface. The gas flow grooves 16e formed on one side surface of one of the separators 16 are arranged in parallel with each other in the through holes 16a, 1a.
6b, a gas flow groove 16 formed on the other side surface and communicating with 6b
f communicates with the through holes 16c and 16d in parallel with each other. The gas flow grooves 17e formed on one side surface of the other separator 17 communicate with the through holes 17a and 17b in parallel with each other, and the gas flow grooves 17f formed on the other side surface are parallel to each other. In this state, the through holes 17c and 17d communicate with each other.

By the way, in the fuel cell 10 of this type, the gaskets 14 and 15 function to prevent leakage of each gas from the joint surface of each constituent member. Is separator 1
6, 17 surrounding each part of each gas flow groove 16e, 17e communicating with each through hole 16a, 16b, 17a, 17b, each through hole 16c of each gas flow groove 16f, 17f in the separator 16,17, 16d, 17
The part surrounding the part communicating with c and 17d is easily bent by the action of the clamping force, and such a bending is caused by each gasket 14,
When generated in 15, the gas flow grooves 16e, 17e, 16
Gas may leak from the communicating portion (tip portion) of f and 17f.

Therefore, in the fuel cell disclosed in the above publication, a gas permeable member such as a hollow pipe is provided at the tip of each gas flow groove 16e, 17e, 16f, 17f of each separator 16, 17. Surface pressure securing member),
By ensuring the surface pressure of each gasket 14, 15 at the tip of each gas flow groove 16e, 17e, 16f, 17f, and preventing the occurrence of flexure at the relevant part of each gasket 14, 15 due to the occurrence of flexure It prevents the leakage of gas.

FIG. 4 shows an example in which hollow pipes 19a and 19b are fitted to the tip ends of the gas flow grooves 16e of the separator 16. In each of the gas flow grooves 16e, the tip thereof faces the through hole 16a (gas inflow hole), and each gas flow groove 16e is a communication site with the gas inflow hole 16a.
A large number of hollow pipes 19 that are surface pressure securing members
a and 19b are fitted together. In addition, each gas distribution groove 16
Similarly, a large number of hollow pipes 19a and 19b, which are surface pressure securing members, are also fitted to the tip end portion which is a communicating portion with the through hole 16b (gas outflow hole) of e.

[0010]

As described above, in the fuel cell disclosed in the above-mentioned publication, the surface pressure of the tip portion of each gas flow groove of the separator is ensured, so that the gasket bends at that portion. To prevent the occurrence of
It effectively prevents gas leakage.

However, in the fuel cell,
As a means for securing the surface pressure of the tip portion in each gas flow groove of the separator, a means for fitting a surface pressure securing member such as a pipe or a porous body to all the tip portions of each gas flow groove of the separator is adopted. Therefore, it is very troublesome and time-consuming to fit the surface pressure securing member to the tip of each gas flow groove of each separator without overlooking it. Will significantly increase the manufacturing cost of the fuel cell stack including the fuel cell as one unit.

Therefore, an object of the present invention is to integrally form a surface pressure securing portion for securing the surface pressure of the gasket at the tip of each gas flow groove in the separator, and to secure the surface pressure at that portion. To eliminate the need for fitting the surface pressure securing member to the tip of each gas flow groove of the separator, and to manufacture a fuel cell, and thus a fuel cell stack having the fuel cell as one unit. It is to suppress the increase in cost.

[0013]

The present invention relates to a fuel cell separator, which is disposed on each side of a solid electrolyte membrane having an electrode on each side through a sealing member to form the solid electrolyte membrane. A separator that forms a reaction chamber into which a fuel gas flows on one side surface and forms a reaction chamber into which an oxidant gas flows into the other side surface of the solid electrolyte membrane,
On one side surface, a gas flow groove for the fuel gas communicating with the gas inflow passage and the gas outflow passage of the fuel gas passing therethrough, or a flow of the oxidant gas communicating with the gas inflow passage and the gas outlet passage for the oxidant gas penetrating The present invention is applied to a fuel cell separator in which grooves are formed.

Thus, the fuel cell separator according to the present invention is a fuel cell separator of the above type,
A communicating portion between the gas flow groove and the gas inflow path, and
The communicating portion between the gas flow groove and the gas outflow passage is formed in a plurality of narrow groove portions having a width smaller than the groove width of the gas flow groove.

In the fuel cell separator according to the present invention, a plurality of gas flow grooves and a large number of narrow groove portions are provided on one side surface, and these gas flow grooves and the narrow groove portions are provided between the portions facing each other. A configuration may be adopted in which recesses that are lower than the tops of the side wall portions that form the flow grooves and the narrow groove portions and that extend in the width direction of these gas flow grooves are interposed. In this case, it is preferable that the bottoms of the recesses interposed between the gas flow grooves and the narrow groove portions are formed on the same flat surface as the bottoms of the gas flow grooves and the narrow groove portions.

[0016]

In the fuel cell separator according to the present invention, the communicating portion between the gas flow groove and the gas inflow passage and the communicating portion between the gas flow groove and the gas outflow passage are formed in a plurality of narrow groove portions. Thus, the portion where the narrow groove portion is formed functions as a surface pressure securing portion that secures the surface pressure of the gasket. Therefore, it is possible to prevent the gasket from being bent at the relevant portion, and thereby to prevent the gas from leaking at the relevant portion.

Therefore, in the separator, the work of fitting the surface pressure securing member to the tip of each gas flow groove of the separator is completely unnecessary, and the fuel cell, and by extension,
An increase in the manufacturing cost of the fuel stack including the fuel cell as one unit can be significantly suppressed.

Therefore, in the fuel cell separator according to the present invention, the plurality of narrow groove portions provided at the communicating portion between the gas flow groove and the gas inflow passage facilitate the introduction of gas from the gas inflow passage into the gas flow groove. In addition, the plurality of narrow groove portions provided at the communicating portion between the gas circulation groove and the gas outflow passage function to smoothly outflow the gas from the gas circulation groove to the gas outflow passage. As a result, the flow of the gas in the gas flow groove becomes even and smooth, and the gas enhances the contact efficiency with the solid electrolyte membrane to improve the power generation efficiency.

In the fuel cell separator according to the present invention, between the portions where the plurality of gas circulation grooves and the narrow groove portion face each other, the gas circulation groove is lower than the top of the side wall portion forming the gas circulation groove and the narrow groove portion. With the configuration including the recess extending in the width direction, even if one or more of the narrow groove portions are clogged, the gas introduced from the remaining narrow groove portion is temporarily buffered by the recess portion and uniformly distributed in each gas flow groove. Inflow in a divided state. In this case, if the bottom of the recess is formed on a flat surface common to the bottoms of the gas flow grooves and the narrow groove portions, the gas introduced into the gas flow grooves flows more smoothly.

[0020]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings. The fuel cell separator according to the present invention is shown in FIGS.
Separator 1 which is a constituent member of the fuel cell 10 shown in FIG.
5 and 6, a part of a fuel cell separator according to an example of the present invention is shown.
The separator 20 constitutes a fuel cell by adopting it instead of the separator 16 which is a constituent member of the fuel cell 10, and the fuel cell employing the separator 20 is substantially the same as the fuel cell 10. The configuration has the same function.

FIG. 5 is a perspective view showing a main part of the separator 20 according to the present invention, and FIG. 6 is an enlarged perspective view showing a part thereof. FIG. 5 corresponds to FIG. 4 showing the main part of the separator 16. The separator 20 is shown in FIG.
4 has basically the same configuration as the separators 16 and 17 shown in FIG. 4, but the structure of the tip of the gas flow groove formed on each side surface is different from that of the separator 16. In the separator 20, similarly to the separator 16, through holes corresponding to the respective through holes 16a to 16d are formed, a gas circulation groove corresponding to the gas circulation groove 16e is formed on one side surface, and a gas is formed on the other side surface. A gas circulation groove corresponding to the circulation groove 16f is formed.

On one side surface 21 of the separator 20, four gas flow grooves 22a, 22b, 22 are arranged in parallel with each other.
c, 22d are formed, and these gas flow grooves 22
The upstream sides of a to 22d communicate with the gas inflow path 23 (fuel gas inflow path) which is a through hole, and these gas flow grooves 2
The downstream side of 2a to 22d communicates with a gas outflow passage (fuel gas outflow passage) (not shown) which is a through hole. In addition, in the separator 20, four gas circulation grooves that are parallel to each other are also formed on the other side surface, and the upstream side of these gas circulation grooves is a gas inflow passage (oxidant gas inflow passage) that is a through hole. ), And the downstream side of these gas flow grooves communicates with a gas outflow passage (oxidant gas outflow passage) (not shown) which is a through hole.

In the separator 20 having such a structure, one side edge portion of the gas inflow passage 23 on the one side surface 21, in other words, the gas circulation grooves 22a, 22b, 22c, 22d.
Is formed with a large number of small width groove portions 24a in a portion communicating with the gas inflow passage 23, and the formation portion 2 of the small width groove portion 24a is formed.
4, and a strip-shaped recess 25 is formed between the gas circulation grooves 22a, 22b, 22c, and 22d. Recess 2
5 extends over the entire length in the direction in which the gas flow grooves 22a to 22d and the narrow groove portions 24a are arranged in parallel,
It is interposed between each of the gas flow grooves 22a to 22d and each of the narrow groove portions 24a. The gas flow grooves 22a to 22d, the narrow groove portions 24a, and the bottoms of the recesses 25 are formed on a common flat surface, and the gas flow grooves 22a to 22d.
2d, the narrow groove portions 24a, and the tops of the side walls forming the recesses 25 are formed on a flat surface common to the one side surface 21 of the separator 20. One side 21 of this configuration
In the above, the formation portion 24 of the narrow groove portion 24a functions as a surface pressure ensuring portion for the gasket.

In the separator 20, the gas flow grooves 22a, 22b, 22c on the one side surface 21,
A large number of small width groove portions are also formed in the portion where 22d communicates with the gas outflow passage, and a band-shaped recess is formed between the formation portion of the small width groove portion and the tip portion of each gas flow groove. As a result, the formation portion of the narrow groove portion functions as a surface pressure ensuring portion for the gasket. Further, the structure of the portion of the gas circulation groove formed on the other side surface of the separator 20 that communicates with the gas inflow path and the gas outflow path is also formed to have the same structure as the structure on the one side surface 21 side described above.

In the fuel cell separator 20 having the above-described structure, the communicating portion between the gas flow grooves 22a to 22d and the gas inflow passage 23 is formed with a large number of narrow groove portions 24a.
4 is formed, and the formation portion 24 functions as a surface pressure securing portion that secures the surface pressure of the gasket. Therefore, it is possible to effectively prevent the gasket from being bent at the relevant portion, and thereby to prevent the gas from leaking from the relevant portion. Further, also in the communication portion between the gas flow grooves 22a to 22d and the gas outflow passage, the same surface pressure securing portion is formed, and the communication portion between the gas flow passage and the gas inflow passage and the gas outflow passage formed on the other side surface. In the same manner, the surface pressure securing portion is also formed.

Therefore, in the separator 20,
It is completely unnecessary to fit the surface pressure securing member to the tip end portion of each gas flow groove for forming the surface pressure securing portion, and the fuel cell, and thus the fuel including the fuel cell as one unit, is not required. An increase in stack manufacturing cost can be significantly suppressed.

In the separator 20, however, a large number of narrow groove portions 24a provided at the communicating portions of the gas flow grooves 22a to 22d and the gas inflow path 23 are provided in the gas inflow path 23.
From the gas flow grooves 22a to 22d to facilitate the introduction of gas, and a large number of narrow groove portions provided at the communicating portions of the gas flow grooves 22a to 22d and the gas outflow passage are provided in the gas flow grooves 22a. It functions to smooth the outflow of gas from the ~ 22d to the gas outflow passage. Therefore, each gas distribution groove 22a
The gas flow at ~ 22d becomes even and smooth,
The gas increases the contact efficiency with the solid electrolyte membrane and improves the power generation efficiency.

Further, in the separator 20, a plurality of gas flow grooves 22a to 22d and a large number of narrow groove portions 24a are formed.
Since the gas circulation grooves 22a to 22d and the narrow groove portion 24a are provided with the recesses 25 extending over the entire length in parallel between the portions facing each other, one of the narrow groove portions 24a is formed.
Even if one or more of them are clogged, the gas introduced from the remaining narrow groove portions 24a is temporarily buffered by the recesses 25 and flows into each of the gas flow grooves 22a to 22d in a uniformly divided state. In this case, since the bottom of the recess 25 is formed on a flat surface common to the bottoms of the gas flow grooves 22a to 22d and the narrow groove portions 24a, the gas flow grooves 22a are formed.
The gas introduced into ~ 22d flows more smoothly.

The separator 20 useful in this way is
It can be manufactured by various methods. The separator 20 shown in FIGS. 5 and 6 is provided on the side surface of the flat substrate 20a,
The flat plate portion 20b and the gas distribution groove 22 are formed by the screen printing method.
a to 22d, the narrow groove portion 24a, and the recess 25 are formed, but by injection molding or press molding,
These constituent parts can be integrally formed, and
It is also possible to adopt a method in which all the portions except the narrow groove portion 24a are integrally formed and the narrow groove portion 24a is formed by excimer laser processing, cutting processing, or the like.

In addition, in the separator 20, the wall portion for partitioning each of the gas flow grooves 22a to 22d is formed into a bank-shaped continuous wall portion, and each of the gas flow grooves 22a to 22d is formed in parallel with each other. However, replacing the wall with a continuous wall like a bank, densely implanting a large number of cylinders or prisms to form each gas flow groove in a regular array shape or an irregular array shape. You can also choose to do so.

[Brief description of drawings]

FIG. 1 is a perspective view of a fuel cell stack including a fuel cell that employs a separator to which the present invention is applied as one unit.

FIG. 2 is a vertical sectional view of the fuel cell.

FIG. 3 is an exploded perspective view showing the fuel cell in a disassembled state.

FIG. 4 is a partial perspective view showing a structure on one side surface side of a conventional separator.

5 is a partial perspective view of a separator according to an example of the present invention, corresponding to FIG.

FIG. 6 is a partially enlarged perspective view of the separator.

[Explanation of symbols]

10 ... Fuel cell, 11 ... Solid electrolyte membrane, 11a to 11d
... Through hole, 12, 13 ... Electrode, 14, 15 ... Gasket, 14a-14d, 15a-15d ... Through hole, 16,
17 ... Separator, 16a-16d, 17a-17d ...
Through holes, 16e, 17e, 16f, 17f ... Gas flow grooves, 18a-18d ... Assembly bolts, 19a, 19b ... Hollow pipe, 20 ... Separator, 20a ... Substrate, 20b ...
Flat plate portion, 21 ... One side surface, 22a, 22b, 22c, 22
d ... Gas circulation groove, 23 ... Gas inflow passage, 24 ... Groove portion forming portion (surface pressure securing portion), 24a ... Small width groove portion, 25 ... Recessed portion.

Claims (3)

[Claims] 1. A reaction chamber, which is disposed on each side of a solid electrolyte membrane having electrodes on each side with a sealing member, to form a reaction chamber into which a fuel gas flows into one side of the solid electrolyte membrane. Together with the separator forming a reaction chamber into which the oxidant gas flows on the other side surface side of the solid electrolyte membrane, one side surface side, of the fuel gas communicating with the gas inflow path and the gas outflow path of the penetrating fuel gas In a fuel cell separator in which a gas flow groove or a gas flow groove of an oxidant gas communicating with a gas inflow path and a gas outflow path of the oxidant gas passing therethrough is formed, the gas flow groove and the gas inflow path A fuel cell separator, characterized in that the communication portion and the communication portion between the gas flow groove and the gas outflow passage are formed in a plurality of narrow groove portions having a width smaller than the groove width of the gas flow groove. . 2. The fuel cell separator according to claim 1, wherein a plurality of gas flow grooves and a large number of small width groove portions are formed on one side surface of the separator between the facing portions. A fuel cell separator, characterized in that recesses extending in the width direction of the gas flow groove and the narrow groove portion, which are lower than the top portion of the side wall portion, are interposed. 3. The fuel cell separator according to claim 2, wherein the bottoms of the recesses interposed between the gas flow grooves and the narrow groove portions are flat surfaces common to the gas flow grooves and the narrow groove portions. A separator for a fuel cell, characterized in that