JPH0644980A - Separator for fuel cell - Google Patents

Abstract

PURPOSE:To provide high plane accuracy easy for production and mass production by providing flow speed distribution of gas almost uniform in a reaction surface so that short-circuiting between cells is prevented from being easily generated and a pressure loss in the reacion surface can be adjusted further with softness. CONSTITUTION:A separator compriscis a center plate 12, corrugated materials 13, 14 and anode/cathode mask plates 15, 16. In this separator, the corrugated material 14 is mounted on the upper/lower surface total units of the center plate 12, and further the corrugated materials 13, 14 are arranged in a direction orthogonal to flow paths of the corrugated materials 13, 14 in a reaction surface in at least a mask plate part.

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 there.

[0002]

2. Description of the Related Art In a molten carbonate fuel cell (FIG. 11), a thin flat electrolyte plate (tile) 1 is used as a fuel electrode (anode).
Since the voltage is low (about 0.8 V) in the unit cell 4 sandwiched between the plate-shaped electrodes of 2 and the air electrode (cathode) 3, the electrodes are practically stacked in multiple layers via the conductive bipolar plate (separator) 5. Used as a battery. This laminated battery is called a stack.

As shown in FIG. 12, 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. 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,
Especially 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. 13, an external manifold system (A) for directly supplying the process gas from the side surface of the stack and a penetrating perpendicular to the separator itself. There is an internal manifold system (B) which is provided with a manifold 8 and supplies a process gas to each cell via this manifold, but it is an internal manifold system in that it is not affected by a change in stack height or unevenness on the stack side surface. Are considered excellent.

The present invention relates to such a parallel flow internal manifold type separator. As described above, the fuel cell separator has a plurality of functions such as a partition plate that partitions the anode gas and the cathode gas, a current collector that connects each cell, and a manifold that supplies the anode gas and the cathode gas to each cell. ing. Initially, such a separator was manufactured by machining, but with the increase in size and mass production of fuel cells, it has come to be manufactured by means mainly of plastic working.

[0006]

The parallel flow internal manifold type separator (hereinafter simply referred to as a separator) has various advantages as described above, but the anode manifold and the cathode manifold are adjacent to each other on the same side surface of the separator. Therefore, it is difficult to supply the other gas to the portion where the one manifold is present, and as a result, it is difficult to uniformly supply the process gas to the reaction surface of each cell. For example, on the reaction surface on the anode side, there is a problem that the flow velocity is high in a portion close to the anode manifold and is low in a portion far from the anode manifold (a portion near the cathode manifold). Such non-uniformity of the flow velocity may cause a fuel depletion portion on a part of the reaction surface, particularly when the fuel utilization rate of the fuel cell is high (for example, 80% or more), and damage the cell from this portion. Therefore, it has been conventionally desired that the gas flow velocity on the reaction surface be as uniform as possible.

In order to meet this demand, a separator having a uniform flow velocity is provided by providing a resistor in the lateral direction of the flow path of the reaction part and making the pressure loss of the gas flowing through each part substantially constant. It was proposed by the applicant of the present application (Japanese Patent Application No. 63-269405). However, the separator having such a configuration cannot adjust the magnitude of resistance, that is, the magnitude of pressure loss, and it is necessary to match the dimensions of the resistor with those of other components, which makes production difficult and mass production difficult. There was a problem.

For the same purpose, there has been proposed a fuel cell in which a throttle is formed at a position where a gas in the cell makes a U-turn (Japanese Utility Model Publication No. 4-8611). There was a problem that could not be applied to the separator. Further, a configuration has been proposed in which the inside of the separator other than the reaction part is made as hollow as possible to allow the process gas to easily spread in the lateral direction outside the reaction part of the separator (Japanese Patent Application No. 1-34058). The separator has a problem that the magnitude of pressure loss cannot be adjusted, and the separator may be distorted by heat during operation, resulting in short circuit between cells.

The present invention was created to solve such a problem. That is, an object of the present invention is to provide a separator in which the gas flow velocity distribution on the reaction surface is substantially uniform. A further object of the present invention is to provide a separator that is unlikely to cause a short circuit between cells.

Another object of the present invention is to provide a separator capable of adjusting the pressure loss in the reaction section and improving gas distribution before entering the reaction section. Further, the present invention is flexible, has high plane accuracy,
It is also an object of the present invention to provide a separator that is easy to produce and easy to mass produce.

[0011]

According to the present invention, a flat center plate having an opening for an anode gas and an opening for a cathode gas, and an elongated flow path continuously bent in a U-shape are provided. And a corrugated material in which the flow paths are offset by a fixed length, the flexible corrugated material being closely attached to the upper and lower surfaces of the center plate, and the upper and lower portions of the corrugated material being closely attached. A fuel cell separator comprising: a flat anode mask plate and a cathode mask plate, each of which has an opening for an electrode in a central portion and an opening for an anode gas and an opening for a cathode gas in a peripheral portion. plate,
The anode mask plate and the cathode mask plate are airtightly connected to each other at the outer peripheral portion of the separator, and the inner ends of the anode gas openings of the center plate and the cathode mask plate are airtightly connected to each other at the anode manifold portion. The inner end portions of the cathode gas openings of the anode mask plate are airtightly connected to each other in the cathode manifold portion, the corrugated material is attached to the entire upper and lower surfaces of the center plate, and at least the corrugated material of the mask plate portion is A fuel cell separator is provided, in which the flow paths are arranged in a direction orthogonal to the flow direction of the reaction section.

According to a preferred embodiment of the present invention, the corrugated material is arranged such that its flow path is in the electrode portion in a direction from the inlet to the outlet of the manifold. Further, according to the present invention, a flat center plate having an opening for an anode gas and an opening for a cathode gas, and an elongated channel continuously bent in a U shape, and the channel is A corrugated material that is offset by a fixed length, and is a flexible corrugated material that is closely attached to the upper and lower surfaces of the center plate, and a corrugated material that is closely attached to the upper and lower portions of the corrugated material and has a central portion. A flat plate-shaped anode mask plate and a cathode mask plate each having an electrode opening, and an anode gas opening and a cathode gas opening in the periphery thereof, the center plate, the anode mask plate, and The cathode mask plate is hermetically connected to the outer peripheral portion of the separator, and the center plate and the cathode mask plate are connected to each other. The inner end portion of the cathode gas opening is connected hermetically to one another at the anode manifold, the center plate and the inner end portion of the cathode gas openings of the anode mask plate is coupled hermetically to each other at the cathode manifold portion,
Further, in the corrugated material, the flow paths are arranged in the direction from the inlet to the outlet of the manifold in most of the electrode portion,
Some are arranged in a direction orthogonal to this.

Further in accordance with a preferred embodiment of the present invention,
The part of the corrugated material that is orthogonal to each other is an inlet portion and an outlet portion of the electrode portion.

[0014]

[Function] A corrugated material (hereinafter, referred to as an offset corrugate) having a long and narrow flow channel continuously bent in a U-shape and the flow channel being offset by a constant length.
It was found that the gas easily flows in the direction of the flow path, the pressure loss due to the flow is small, and the gas hardly flows in the direction orthogonal to the flow path, and thus the pressure loss is large. As a result of experiments, it was found that the ratio of this pressure loss was at least 10 times in the range of use of the separator and 100 times or more in the region where the flow velocity was high. The present invention is based on such findings.

That is, according to the above-mentioned structure of the present invention, since the flow paths are arranged in the direction orthogonal to the flow direction of the reaction section at least in the mask plate portion, the gas flowing from the manifold into each separator has a resistance. It is much easier to flow in the direction orthogonal to the flow direction of the reaction section, that is, in the direction of connecting the manifolds on the inlet side, than in the direction of entering the large reaction surface. Therefore, most of the gas spreads in the direction orthogonal to the flow direction of the reaction section, that is, in the lateral direction and then flows to the reaction surface, so that the flow velocity distribution of the gas on the reaction surface becomes substantially uniform.

Further, since the corrugated material is attached to the entire upper and lower surfaces of the center plate, an insulating material, for example, an electrolyte plate can be interposed between the entire surface of the mask plate, and the mask plate can be distorted by heat. They do not come into direct contact with each other, and there is no risk of short-circuiting between cells. Further, by arranging a part of the corrugated material of the electrode portion in the direction orthogonal to the flow path of the corrugated material of the reaction portion, the pressure loss in the reaction portion can be freely adjusted to enter the reaction portion. Promotes lateral gas diffusion in the front,
Gas distribution can be improved.

Further, since only the flexible corrugated material is interposed between the center plate and the mask plate,
The entire separator is flexible and can maintain high plane accuracy. Furthermore, since the above-mentioned configuration only changes the direction of the corrugated material, the same corrugated material can be used, no special parts are required, and production is easy and mass production is easy.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 is a plan view of a separator according to the present invention, FIG. 2 is a partial cross-sectional view of a peripheral portion of the separator of FIG. 1, FIG. 3 is a partial cross-sectional view showing an anode gas manifold portion, and FIG. It is a fragmentary sectional view showing a manifold part. Although the upper surface is the cathode side and the lower surface is the anode side in these drawings, the present invention is not limited to this, and the upper surface may be the anode side and the lower surface may be the cathode side.

In 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 an anode manifold 8a and a cathode manifold 8b which penetrate the separator are provided in the upper and lower portions. Has been. In this figure, the upper manifold is the inlet side and the lower manifold is the outlet side. The process gas (anode gas and cathode gas) supplied from the manifold flows from the top to the bottom of the cathode 3 (and the anode 2) (inside the separator).

As is clear from FIGS. 2 to 4, the separator 10 according to the present invention has a flat center plate 1 having an anode gas opening 9 and a cathode gas opening 11.
2 and the flexible corrugated materials 13 and 14 closely attached to the upper and lower surfaces of the center plate 12, and the upper and lower portions of the corrugated materials 13 and 14 closely attached, and the electrode openings 15a and 16a in the central portion. , A flat plate-shaped anode mask plate 15 and cathode mask plate 16 having an anode gas opening 9 and a cathode gas opening 11 in the periphery
Consists of. The corrugated materials 13 and 14 have a long and narrow channel continuously bent in a U-shape, and the channels are offset by a constant length.

As shown in FIG. 2, the center plate 12 and the anode mask plate 1 are formed on the outer peripheral portion of the separator 10.
5 and the cathode mask plate 16 are hermetically connected to each other, whereby the anode side (lower surface) and the cathode side (upper surface) are separated by the center plate 12 to prevent mixing of the anode gas and the cathode gas. As shown in the figure, the outer peripheral portion of the mask plate is preferably narrowed down to the position of the center plate by pressing or the like. The center plate and both mask plates may be connected by any means, for example, welding, brazing, bonding, caulking or the like. The anode 2 and the cathode 3 are fitted into the electrode openings 15a and 16a. The thicknesses of the anode 2 and the cathode 3 are substantially the same as those of the anode mask plate 15 and the cathode mask plate 16, so that the surface of the separator can be made completely flat. Although not shown, an aperture plate such as a punching plate may be interposed between the corrugated material and the mask plate, if necessary.

Further, as shown in FIG. 3, the inner ends of the center plate 12 and the anode mask opening 9 of the cathode mask plate 16 are hermetically connected to each other in the anode manifold portion 8a, and as shown in FIG. The inner end of the cathode gas opening 11 of the center plate 12 and the anode mask plate 15 is hermetically connected to each other by the manifold portion 8b. It is preferable that the center plate is deformed by pressing as shown in the figure. The connection may be made by any means such as welding, brazing, gluing, caulking or the like. As a result, the mixing of the anode gas and the cathode gas can be prevented, and the anode gas and the cathode gas can be supplied to the anode side and the cathode side, respectively.

FIGS. 5 and 6 show an example of the arrangement of the corrugated material in FIG. 1 with the mask plate omitted. In this figure, the corrugated material is attached to the entire upper and lower surfaces of the center plate, and at least in the mask plate portion 14a, the flow paths are arranged in a direction orthogonal to the flow direction of the reaction section, that is, in the direction in which the flow paths connect the manifolds. ing. As a result, the gas flowing in from the manifold flows more than in the direction in which it enters the reaction surface with a large resistance.
Much easier to flow in the direction that connects the manifolds. Therefore, most of the gas spreads in the direction connecting the manifolds and then flows to the reaction surface, so that the flow velocity distribution of the gas on the reaction surface becomes substantially uniform.

As shown in FIG. 6, the corrugated material is arranged in the direction in which the flow path extends from the inlet to the outlet of the manifold in most of the electrode portion 14b and in the direction orthogonal to this in the portion 14c. May be. Further, as shown in this figure, it is preferable that a part of the corrugated material 14c which is orthogonal to each other be used as an inlet portion and an outlet portion of the electrode portion. With this configuration, the same resistance can be applied to the reaction surface of the separator in the width direction.

FIG. 7 is a diagram showing the experimental results of measuring the pressure loss of this corrugated material (anode side). In this figure, the lower line shows the pressure loss in the direction along the flow path of the corrugated material, and the upper line shows the pressure loss in the direction perpendicular to the flow path. In the figure, the horizontal axis is the Reynolds number R
e, the vertical axis represents the pipe friction coefficient f. As is clear from the figure, the offset corrugate allows gas to easily flow in the direction of the flow path, so pressure loss due to the flow is small, and it is difficult for gas to flow in the direction orthogonal to the flow path, and thus the pressure loss is large. . That is, from FIG. 7, the range of use of the separator (R
It can be seen that there is a difference of at least 10 times when e is within 100) and 100 times or more in the region where the flow velocity is fast.

FIG. 8 shows the fuel utilization rate Uf (%) and pressure loss dP (mm) of an actual separator using this corrugated material.
It is an experimental result which shows the relationship with Aq). In this figure, the four lines are from the bottom, (A) When there is no horizontal corrugated material in the reaction part, (B) When a horizontal corrugated material with a width of 50 mm is installed at the entrance and exit of the reaction part, (C) 100 m
In case of horizontal corrugated material with m width, (D) 150 mm
In the case of the width, (E) the case of the same width of 200 mm is shown. As is clear from this figure, the pressure loss in the reaction section can be freely adjusted by changing the width of the corrugated material that is made orthogonal (sideways).

Example 1 FIG. 9 is another test comparing the flow velocity distributions of a conventional separator (Japanese Patent Application No. 1-34058 and Japanese Patent Application No. 63-269405) and the separator of the present invention shown in FIG. The results are shown. In this figure, the upper circle shows the inlet manifold and the four curves show the leading end of the flow after a certain time. In this figure, (A) is actual application 1-340.
Conventional separator according to No. 58, (B) is Japanese Patent Application No. 63-
Conventional separator according to No. 269405, (C) is FIG.
The case of the separator of the present invention shown in FIG.

By comparing (A), (B), and (C) of FIG. 9, it can be seen that the flow velocity distribution (distance between curves) of (C) is almost uniform.

That is, according to the above-described structure of the present invention, since the flow paths are arranged in the direction orthogonal to the flow direction of the reaction section at least in the mask plate portion, the gas flowing from the manifold into each separator has a resistance. It is much easier to flow in the direction connecting the inlet side manifolds than it is in the direction entering the large reaction surface. Therefore, most of the gas spreads in the direction orthogonal to the flow direction of the reaction section, that is, in the direction connecting the inlet side manifolds and then flows to the reaction surface, so that the gas flow velocity distribution on the reaction surface becomes substantially uniform.

Further, since the corrugated material is attached to the entire upper and lower surfaces of the center plate, an insulating material, for example, an electrolyte plate can be interposed between the entire surface of the mask plate, and the mask plate can be distorted by heat. They do not come into direct contact with each other, and there is no risk of short-circuiting between cells. Further, by arranging a part of the corrugated material of the electrode portion in a direction orthogonal to the flow path of the corrugated material of the reaction portion, the magnitude of pressure loss in the reaction portion can be freely adjusted. As a result, the distribution of the gas before it enters the reaction section is improved.

Further, since only the flexible corrugated material is interposed between the center plate and the mask plate,
The entire separator is flexible and can maintain high plane accuracy. Furthermore, since the above-mentioned configuration only changes the direction of the corrugated material, the same corrugated material can be used, no special parts are required, and production is easy and mass production is easy.

[0032]

As described above, according to the present invention, the gas flow velocity distribution on the reaction surface is substantially uniform, it is difficult to cause a short circuit between cells, and the magnitude of the pressure loss in the reaction portion can be adjusted. It is possible to provide a separator that is flexible, has high plane accuracy, is easy to produce, and can be easily mass-produced.

[Brief description of drawings]

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

FIG. 2 is a partial cross-sectional view of a peripheral portion of the separator shown in FIG.

FIG. 3 is a partial cross-sectional view showing a manifold portion for anode gas.

FIG. 4 is a partial cross-sectional view showing a manifold portion for cathode gas.

5 is a diagram showing an example of an arrangement of corrugated members in FIG.

FIG. 6 is a diagram showing another example of the arrangement of corrugated members in FIG.

FIG. 7 is a diagram showing an experimental result of measuring a pressure loss of a corrugated material.

FIG. 8 is a diagram showing a relationship between a fuel utilization rate of a separator and a pressure loss.

FIG. 9 is another diagram comparing the flow velocity distribution with the conventional separator of the present invention.

FIG. 10 is a schematic configuration diagram of a molten carbonate fuel cell.

FIG. 11 is a diagram showing a method of supplying an anode gas and a cathode gas.

FIG. 12 is a diagram showing a means for supplying a process gas to each 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 9 Anode Gas Opening 10 Separator 11 Opening for Cathode Gas 12 Center Plate 13, 14 Corrugated Material 15 Anode Mask Plate 16 Cathode Mask Plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuyuki Arama 3-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toni Technical Center

Claims (4)

[Claims] 1. A flat center plate having an opening for an anode gas and an opening for a cathode gas, and an elongated channel continuously bent in a U-shape,
A corrugated material in which the flow paths are offset by a fixed length, and a flexible corrugated material that is closely attached to the upper and lower surfaces of the center plate; A fuel cell separator comprising: a plate-shaped anode mask plate and a cathode mask plate that are attached and have an electrode opening in the central part and an anode gas opening and a cathode gas opening in the peripheral part, the center plate comprising: The anode mask plate and the cathode mask plate are airtightly connected to each other at the outer periphery of the separator, and the inner ends of the anode gas openings of the center plate and the cathode mask plate are airtightly connected to each other at the anode manifold part. Inner end of cathode gas opening of anode mask plate Are airtightly connected to each other at a cathode manifold portion, and further, the corrugated material is attached to the entire upper and lower surfaces of the center plate, and at least the corrugated material of the mask plate portion has a channel orthogonal to the flow direction of the reaction portion. A fuel cell separator, wherein the fuel cell separator is arranged in a direction. 2. The fuel cell separator according to claim 1, wherein the corrugated material has flow paths arranged in an electrode portion in a direction from an inlet to an outlet of the manifold. 3. A flat center plate having an opening for an anode gas and an opening for a cathode gas, and an elongated channel continuously bent in a U-shape,
A corrugated material in which the flow paths are offset by a fixed length, and a flexible corrugated material that is closely attached to the upper and lower surfaces of the center plate; A fuel cell separator comprising: a plate-shaped anode mask plate and a cathode mask plate that are attached and have an electrode opening in the central part and an anode gas opening and a cathode gas opening in the peripheral part, the center plate comprising: The anode mask plate and the cathode mask plate are airtightly connected to each other at the outer periphery of the separator, and the inner ends of the anode gas openings of the center plate and the cathode mask plate are airtightly connected to each other at the anode manifold part. Inner end of cathode gas opening of anode mask plate Are airtightly connected to each other in the cathode manifold portion, and further, the corrugated material is arranged in a direction in which the flow path is directed from the inlet of the manifold to the outlet of most of the electrode portion,
Part of the fuel cell separator is arranged in a direction orthogonal to this. 4. The fuel cell separator according to claim 3, wherein the part of the corrugated members that are orthogonal to each other is an inlet portion and an outlet portion of an electrode portion.