JPH0963598A - Separator for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator for a fuel cell, which is soft, high in flatness accuracy, capable of producing in large quantities, remarkably reducing cost, and remarkably reducing bypass flow flowing in a place other than a reaction part. SOLUTION: A separator for a fuel cell comprises an almost square flat plate-shaped cathode mask, a cathode collector, a center plate 13, an anode collector, and an anode mask, and they are stacked in order. The center plate 13 has an electrode recessed and projecting part 13a and a mask recessed and projecting part 13b formed by press working. The center plate 13 has through holes 16, 17 for the whole gases, a closed ring-shaped anode sealing part 13c which encloses an opening of the anode mask and swells on the anode side to support the anode mask, and a closed ring-shaped cathode sealing part 13d which swells on the cathode side to support cathode mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell separator for directly converting chemical energy of a fuel into electric energy, and more particularly to a parallel flow internal manifold type separator for a molten carbonate fuel cell. Is.

[0002]

2. Description of the Related Art In a molten carbonate fuel cell (FIG. 6A), a thin flat electrolyte plate (tile) 1 is used as a fuel electrode (anode).
2 and an air electrode (cathode) 3 sandwiched between flat electrodes 4, and a conductive bipolar plate (separator) 5
Consists of Since the voltage of the separator 5 is low (about 0.8 V) in the single cell 1, the separator 5 is used to form a battery in which these are stacked in multiple stages. Stacked batteries are called a stack.

As shown in FIG. 6B, the fuel gas (anode gas) 6 and the oxidizing gas (cathode gas) 7 are supplied to both sides of each cell in the stack as shown in FIG. 6B. There is a flow (b) and a counterflow (c), but there is a parallel flow in terms of cooling by the process gas (anode gas, cathode gas) of the fuel cell and thermal stress generated in the separator,
Particularly cocurrent (b) is considered to be advantageous.

Further, as a means for supplying the process gas to each cell in the stack, as shown in FIG. 6C, an external manifold system (a) for directly supplying the process gas from the side surface of the stack and a through hole perpendicular to the separator itself are used. There is an internal manifold system (b) which is provided with a manifold 8 and supplies process gas to each cell via this manifold. However, the internal manifold system is not affected by a change in stack height or unevenness of the stack side surface. Are considered excellent.

The present invention relates to such a parallel flow internal manifold type separator.

[0006]

As described above, the fuel cell separator is composed of a partition plate for partitioning the anode gas and the cathode gas, a current collector for connecting the cells, and a gas for supplying the anode gas and the cathode gas to the cells, respectively. It has multiple functions such as a manifold, heat resistance to withstand high temperatures of about 700 ° C or higher, corrosion resistance to highly corrosive molten carbonate, and electrolyte plates (tiles) containing molten carbonate between separators. In addition, the flatness and flexibility of forming a wet seal, and low electric resistance that lowers the internal resistance of the battery are required. Although such a separator was initially manufactured by machining, a significant cost reduction of the separator has been demanded in order to reduce the power generation cost of the fuel cell.

In order to realize such a demand, the applicant of the present application uses a corrugated material that is continuously bent in a U shape, and attaches the corrugated material to both sides of a flat center plate to form a flow path. A separator was invented and filed (JP-A-6-44980). This separator using corrugated material (hereinafter simply referred to as corrugated separator) has only a flexible corrugated material between the center plate and the mask plate, so that the separator as a whole has flexibility and planar accuracy. The heat resistance, corrosion resistance, low electric resistance and the like described above can be satisfied by using a suitable material.

However, such a corrugated separator is
It is necessary to cut the corrugated material into various shapes, and it is necessary to attach many different shaped corrugated materials to both sides of the center plate.
There is a problem that it is costly, time consuming, and it is essentially difficult to mass-produce and significantly reduce costs. Further, such corrugated separator, in order to form a wet seal around the reaction portion, it is necessary to insert the corrugated material also under the mask plate other than the reaction portion, gas flow through the corrugated material in this portion, There was a problem that a bypass flow was generated which flowed outside the reaction section, the utilization rate of the reaction gas was lowered, and the distribution performance was lowered. Furthermore, in order to prevent this bypass flow, measures such as inserting a blocking plate for blocking the flow are taken, but the structure is further complicated and productivity is deteriorated, and mass production and significant cost reduction are increasing. There was a problem that became difficult.

The present invention was created to solve such a problem. That is, an object of the present invention is to provide a fuel cell separator which is flexible, has high planar accuracy, can be mass-produced, and can significantly reduce the cost. Further, another object of the present invention is to provide a fuel cell separator capable of significantly reducing a bypass flow flowing to a portion other than the reaction portion without contradicting productivity and significant cost reduction.

[0010]

According to the present invention, a cathode mask, a cathode collector, a center plate, an anode collector, and an anode mask, each of which has a substantially rectangular flat plate shape, are components, and these are sequentially stacked for a fuel cell. The separator is a separator, each of which has a plurality of through holes for a cathode gas and a plurality of through holes for an anode gas along two opposing sides, and the cathode mask and the anode mask each house an electrode in a central portion thereof. The cathode collector and the anode collector have a large number of through holes at positions corresponding to at least the openings, and the center plate has a plurality of electrode irregularities for supporting the anode and the cathode, the cathode mask and the anode. A plurality of mask irregularities for supporting the mask, and the center plate and the anode mask. Click, and the separator outer peripheral portion of the cathode mask, and an inner end portion of the center plate and the cathode mask anode gas through-holes of the inner end portion of the cathode gas through-holes of the center plate and the anode mask,
There is provided a fuel cell separator, wherein the separators are airtightly connected to each other.

According to the above-mentioned structure of the present invention, the separator is formed by simply connecting the five components of the substantially rectangular flat plate-shaped cathode mask, cathode collector, center plate, anode collector, and anode mask by welding or the like. Can be completed. Therefore, unlike the corrugated separator, there is no need to cut corrugated materials into various shapes or to attach corrugated materials with different cut shapes to both sides of the center plate, which significantly reduces the cost and time required for assembly. Can be reduced.

Further, the center plate having the electrode uneven portion and the mask uneven portion can be easily formed by pressing a highly flexible thin plate, so that the flexibility is maintained and the plane accuracy is improved. In addition, it has high productivity, mass production is possible, and significant cost reduction is possible.

According to a preferred embodiment of the present invention, the center plate surrounds all the gas through holes and the openings of the anode mask, and bulges toward the anode side to support the anode mask. It further has a ring portion and a closed ring-shaped cathode seal ring portion that extends in parallel to the outside of the anode seal ring portion and bulges toward the cathode side to support the cathode mask. With this configuration, it is possible to prevent the reaction gas from flowing to the outside of each ring-shaped seal ring portion, and these seal ring portions can support the mask plate around the reaction portion. Therefore, by providing each seal ring portion in the vicinity of each reaction portion, it is possible to significantly reduce the bypass flow that flows to the portions other than the reaction portion without adversely affecting productivity and cost reduction.

[0014]

Preferred embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, common portions are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 is a cathode side plan view of a separator according to the present invention, FIG. 2 is an exploded view of the separator of FIG. 1, and FIG. 3 is a cathode side plan view of a center plate constituting the separator. In these figures, the upper side is the cathode side and the lower side is the anode side, but the present invention is not limited to this, and the upper side may be the anode side and the lower side may be the cathode side.

Referring to FIG. 1, a separator 1 according to the present invention.
Reference numeral 0 is a parallel-flow internal manifold type separator, which has a recessed portion into which the cathode 3 (and the anode 2) is fitted in the central portion of both surfaces of the separator, and the anode manifold 8a and the cathode manifold 8b which penetrate the separator in the upper and lower portions in the figure. Is provided. In this figure, the upper manifold is on the inlet side, the lower manifold is on the outlet side, and the process gas (anode gas and cathode gas) supplied from the manifold is below the cathode 3 (and the anode 2) (inside the separator). ) From top to bottom. Note that the gas flow is not limited to this embodiment, and both gases or one gas may flow from bottom to top.

As shown in FIG. 2, the separator 1 of the present invention.
0 is a substantially rectangular flat plate-shaped cathode mask 11,
The cathode collector 12, the center plate 13, the anode collector 14, and the anode mask 15 are used as components, and these are sequentially stacked. In addition, each of the component parts 11, 12, 13, 14, and 15 faces each other.
A plurality of cathode gas through holes 16 and a plurality of anode gas through holes 17 are provided along the sides (upper and lower sides in the figure).
In this figure, the cathode gas through holes 16 are larger round holes provided with four holes each on the upper and lower sides, and the anode gas through holes 17 are similarly provided with two small holes each. It is a round hole. The arrangement of the gas through holes 16 and 17 is not limited to this figure, and can be set freely.

Further, in FIG. 2, the cathode mask 11 and the anode mask 15 have openings 11a and 15a for accommodating electrodes respectively in the central portion, and the cathode 3 and the anode 2 are fitted in these portions, respectively. . Further, the cathode collector 12 and the anode collector 14 are
A plurality of through holes are provided at least at positions corresponding to the openings 11a and 15a, and the process gas supplied from the manifolds 8a and 8b (see FIG. 1) to both surfaces of the center plate 13 is provided in the openings 3a and 15a. It is designed to be supplied to the anode 2.

As shown in FIG. 3, the center plate 13
Are four electrode irregularities 13a supporting the anode and the cathode, the cathode mask 11 and the anode mask 15
And two mask concave and convex portions 13b for supporting the. The electrode concavo-convex portion 13a is in the width direction (horizontal direction in the figure) in this figure.
A flow path press-formed in a corrugated shape extends vertically. In addition, the mask concave-convex portion 13b has a through hole 1 for each gas.
Concavities and convexities radially provided around 6, 17 and the opening 1
It is composed of an uneven portion provided on the gas outflow portions 1a and 15a. With this configuration, each process gas is caused to flow from the upper gas through holes 16 and 17 to the lower gas through holes 16 and 17, and the process gas is passed through the through holes of the cathode collector 12 and the anode collector 14 to the openings 11a and 15a. It can be fed to the cathode 3 and the anode 2 located.

FIGS. 4A and 4B are a sectional view taken along line A and a sectional view taken along line B of FIG. 1, respectively. The cross-sectional view A and the cross-sectional view B are different only in the molding shape of the above-mentioned electrode uneven portion 13a. As shown in FIG. 3, the center plate 13 further includes a ring-shaped anode seal ring portion 13c surrounding all of the gas through holes 16 and 17 and openings 11a and 15a of both masks, and a cathode seal ring portion 13d. are doing. Also, FIG.
As shown in, the anode seal ring portion 13c surrounds the opening 15a of the anode mask 15 and swells toward the anode side to support the anode mask 15, and the cathode seal ring portion 13d supports the anode seal ring portion 13d.
It extends parallel to the outside of c and swells to the cathode side to support the cathode mask 11. The seal ring portions 13c and 13d are press-molded into a closed ring shape as shown in FIG. With this configuration, the reaction gas can be prevented from flowing outside the ring-shaped seal ring portions 13c and 13d, and the mask plates 11 and 15 around the reaction portion can be supported by these seal ring portions 13c and 13d. can do. Therefore, by providing the seal ring portions 13c and 13d in close proximity to the reaction portions, it is possible to greatly reduce the bypass flow flowing to the portions other than the reaction portion without adversely affecting the productivity and the significant cost reduction.

5 (A) and 5 (B) are sectional views taken along line C and D of FIG.
It is sectional drawing. As shown in this figure, the separator outer peripheral portions (A in FIG. 5) of the center plate 13, the anode mask 15, and the cathode mask 11, and the anode gas through holes 1 of the center plate 13 and the cathode mask 11.
An inner end portion (B portion in FIG. 5) of 7 and an inner end portion (C portion in FIG. 5) of the through hole 16 for the cathode gas of the center plate 13 and the anode mask 14 are airtightly connected to each other. These connections may be made by any means, such as welding,
It is good to use brazing, adhesion, or caulking.

With this configuration, the cathode manifold 8
The cathode gas supplied from b is supplied to the center plate 1
3 and the cathode mask 11, and the anode gas supplied from the anode manifold 8a can be supplied between the lower surface of the center plate 13 and the anode mask 15. Further, as shown in FIG. 1, the cathode gas and the anode gas respectively supplied to the upper and lower surfaces of the center plate 13 flow downward through the electrode uneven portion 13a (see FIG. 3) of the center plate 13, and the cathode collector 12 and the anode collector Cathode 3 located in openings 11a and 15a through the through hole of collector 14.
And reach the anode 2 where they react and generate electricity. Further, the unreacted gas and the reaction product flow further downward and are discharged to the outside from the lower manifolds 8a and 8b, respectively.

As described above, according to the configuration of the present invention,
The separator 10 can be completed by simply connecting the five components of the substantially rectangular flat plate-shaped cathode mask 11, cathode collector 12, center plate 13, anode collector 14, and anode mask 15 by welding or the like. Therefore, unlike the corrugated separator, there is no need to cut corrugated materials into various shapes or to attach corrugated materials with different cut shapes to both sides of the center plate, which significantly reduces the cost and time required for assembly. Can be reduced.

Further, the center plate 13 having the electrode uneven portion and the mask uneven portion can be easily formed by pressing a highly flexible thin plate.
The flexibility can be maintained, the plane accuracy can be improved, the productivity is high, the mass production is possible, and the cost can be greatly reduced. It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

[0024]

As described above, the fuel cell separator of the present invention is flexible, has high plane accuracy, can be mass-produced, and can significantly reduce the cost. Further, the productivity and the cost can be significantly reduced. It has an excellent effect that the bypass flow flowing to the portions other than the reaction part can be significantly reduced without violating the above.

[Brief description of drawings]

FIG. 1 is a cathode side plan view of a separator according to the present invention.

FIG. 2 is an exploded view of the separator of FIG.

FIG. 3 is a plan view on the cathode side of a center plate forming a separator.

FIG. 4 is a cross-sectional view taken along the line A and the line B of FIG.

5 is a cross-sectional view taken along the line C and the line D of FIG.

FIG. 6 is an explanatory diagram of a conventional molten carbonate fuel cell.

[Explanation of symbols]

 1 Electrolyte Plate (Tile) 2 Fuel Electrode (Anode) 3 Air Electrode (Cathode) 4 Single Cell 5 Bipolar Plate (Separator) 6 Fuel Gas (Anode Gas) 7 Oxidizing Gas (Cathode Gas) 8 Manifold 8a Anode Manifold 8b Cathode Manifold 9 Anode gas opening 10 Separator 11 Cathode mask 11a Opening 12 Cathode collector 13 Center plate 14 Anode collector 15 Anode mask 15a Opening 16 Cathode gas through hole 17 Anode gas through hole

Claims (2)

[Claims] 1. A fuel cell separator in which a cathode mask, a cathode collector, a center plate, an anode collector, and an anode mask, each of which has a substantially rectangular plate shape, are used as constituent parts, and these are sequentially stacked. , A plurality of through holes for the cathode gas and a plurality of through holes for the anode gas are provided along two opposite sides, and the cathode mask and the anode mask each have an opening for accommodating an electrode in the central portion, and the cathode collector and the anode The collector has a large number of through holes at least at positions corresponding to the openings, and the center plate has a plurality of electrode irregularities supporting the anode and the cathode and a plurality of mask irregularities supporting the cathode mask and the anode mask. The center plate, the anode mask, and the cathode mask. A regulator outer peripheral portion, and the inner end portion of the center plate and the anode gas through holes of the cathode mask, the inner end portion of the cathode gas through-holes of the center plate and the anode mask is coupled hermetically to each other,
A fuel cell separator characterized by the above. 2. The center plate encloses all the gas through holes and the openings of the anode mask, and a closed ring-shaped anode seal ring portion which bulges toward the anode side to support the anode mask, and the anode seal ring. The fuel cell separator according to claim 1, further comprising: a closed ring-shaped cathode seal ring portion that extends in parallel to the outside of the portion and bulges toward the cathode side to support the cathode mask.