JP2004319455A - Flat laminated fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat laminated fuel cell with a reduced burden of operation and an improved loading property. <P>SOLUTION: A conductive separator forming reaction gas flow channels 10, 11 for supplying reaction gas to electrodes 8, 9 of a membrane electrode structure is composed of first separators 4 fitted with a reaction gas flow channel for a fuel electrode and a reaction gas flow channel for an oxidant electrode, and second separators 5 fitted only with either of the reaction gas flow channels. A unit is so made up that the first separators 4, 4 are arranged to pinch the membrane electrode structure so that different reaction gas flow channels are faced with each other, and the second separator 5 is arranged at the membrane electrode structure 3 on which only either of the first separators 4 so as to have its reaction gas flow channel opposed to that of the first separator 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a planar stacked fuel cell in which fuel cells having a membrane electrode structure formed by sandwiching an electrolyte membrane between a fuel electrode and an oxidant electrode are arranged in a plane.

  Conventionally, as a fuel cell, a membrane electrode structure formed by sandwiching an electrolyte membrane between a fuel electrode and an oxidizer electrode is sandwiched between a pair of separators to form a fuel cell, and a plurality of the fuel cells are stacked. Structures are generally known. However, in the fuel cell of this structure, when the number of stacked fuel cells is increased in order to increase the output, the stacked dimensions of the fuel cell are correspondingly increased. Not suitable. In addition, in the fuel cell of this structure, when power generation failure occurs in one fuel cell, each fuel cell is electrically connected in series, so that the entire fuel cell stack is affected. The output will drop significantly. As a solution to such a problem, a planar stacked fuel cell in which fuel cells having a membrane electrode structure are arranged in a plane is proposed.

For example, in Patent Document 1, a plurality of fuel cells in which an oxidizer electrode and a fuel electrode are opposed to each other with an electrolyte membrane interposed therebetween are arranged in a plane so as to be arranged on the same surface, and the fuel of one of the adjacent fuel cells is disposed. A planar stacked fuel cell is disclosed in which a back surface of an electrode and a back surface of an oxidizer electrode of the other fuel cell are electrically connected by a conductive Z-shaped connection plate.
JP-A-2002-56855

  However, in the related art, it takes time and effort to manufacture the conductive Z-shaped connection plate and to assemble the connection plate, and the work load is large, and if the rigidity around the connection plate is not sufficiently ensured. When mounted on a vehicle or the like, a positional shift occurs, and thus there is a problem in terms of mountability.

  The present invention has been made in view of the above-described circumstances, and has as its object to provide a planar stacked fuel cell capable of reducing a work load and improving mountability.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present invention provides an electrolyte membrane (for example, solid polymer electrolyte membrane 7 in the embodiment) and a fuel electrode (for example, anode electrode 8 in the embodiment). A fuel cell (for example, in the embodiment) having a membrane electrode structure (for example, the membrane electrode structure 3 in the embodiment) formed between the oxidant electrode (for example, the cathode electrode 9 in the embodiment). In a flat stack type fuel cell (for example, the flat stack type fuel cell 1 in the embodiment) in which the fuel cells 2) are arranged in parallel in a plane, a reaction of supplying a reaction gas to the electrodes of the membrane electrode structure is performed. A conductive separator forming a gas passage is replaced with a first separator having a reaction gas passage for the fuel electrode and a reaction gas passage for the oxidant electrode provided on one side (for example, in the embodiment). A first separator 4) and a second separator provided with only one of the reaction gas passages (for example, the second separator 5 in the embodiment). The membrane electrode structure is sandwiched and arranged so that different reaction gas passages face each other, and the second separator is provided on the other surface of the membrane electrode structure in which the first separator is arranged on only one surface. The reaction gas passages are arranged so as to face each other to form a unit.

  According to this invention, each of the reaction gas passages formed in the first separator is disposed so as to face the adjacent membrane electrode structure, and the fuel cells in which the first separators are adjacent to each other are provided. Since it becomes a common component of the cells, the adjacent fuel cells can be electrically connected to each other by the first separator, thereby eliminating a special member for connecting the fuel cells. Thus, the work load can be reduced, and sufficient rigidity can be secured at the connecting portion between the adjacent fuel cells, so that the mountability can be improved. Further, since different reaction gases flow through the respective reaction gas passages of the first separator, adjacent fuel cells can be connected in series, and the thickness dimension is reduced to about a single fuel cell. The same high output voltage and output power as in the case where fuel cells are stacked can be obtained while suppressing the fuel cell.

The invention according to claim 2 of the present invention is the invention according to claim 1, wherein the units are stacked in the thickness direction, and the second separators of units adjacent in the stacking direction are electrically connected to each other. In addition, an insulating plate (for example, the insulating plate 6 in the embodiment) is interposed between the first separators of the adjacent units.
According to the present invention, a short circuit can be prevented by the insulating plate interposed between the first separators of the units adjacent to each other in the stacking direction. The output voltage and the output power can be doubled by the number of layers, and a high output voltage and output power can be obtained while suppressing the size of the layers.

The invention according to claim 3 of the present invention is the invention according to claim 2, wherein the second separators between the adjacent units are electrically connected to each other via a terminal (for example, the terminal 14 in the embodiment). The connection is made.
According to the present invention, since each unit can be manufactured in the same shape regardless of the arrangement position, the mountability can be further improved.

  The invention according to claim 4 of the present invention provides a plurality of first electrodes provided with a plurality of reaction gas passages, in which a membrane electrode structure formed by sandwiching an electrolyte membrane between a fuel electrode and an oxidant electrode is arranged in parallel in a plane. Are disposed on both sides of each membrane electrode structure with different reaction gas passages facing each other, and a single reactant gas is provided on the other surface of the membrane electrode structure in which the first separator is disposed on only one side. A plurality of units, each having a second separator provided with a passage facing each other, are provided. The first separator and the second separator of each unit are opposed to each other, and an insulating plate is interposed between the first separators. In addition to the above, a terminal is interposed between the second separators, and the terminals are stacked and arranged.

  According to the present invention, a special member is not required to connect the fuel cells, and units having the same shape that ensure sufficient rigidity at the connection point between the adjacent fuel cells are separated by the insulating plate. Electrical connection is made via terminals while preventing short circuits, so the output voltage and output power obtained by each unit can be doubled by the number of layers, and high output voltage and output power can be obtained while suppressing the size of the layers. Can be obtained.

  As described above, according to the first aspect of the present invention, a special member is not required for connecting the fuel cells, the work load can be reduced, and the connection points between the adjacent fuel cells can be reduced. Sufficient rigidity can be ensured, and the mountability can be improved. Further, since different reaction gases flow through the respective reaction gas passages of the first separator, adjacent fuel cells can be connected in series, and the thickness dimension is reduced to about a single fuel cell. The same high output voltage and output power as in the case where fuel cells are stacked can be obtained while suppressing the fuel cell.

According to the second aspect of the present invention, the output voltage and output power obtained in each unit can be doubled by the number of layers, and high output voltage and output power can be obtained while suppressing the size of the layers. It becomes possible.
According to the third aspect of the present invention, since each unit can be manufactured in the same shape regardless of the arrangement position, the mountability can be further improved.
According to the fourth aspect of the present invention, the work load can be reduced and the mountability can be improved, and the output voltage and output power obtained in each unit can be doubled by the number of layers. , And high output voltage and output power can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a plan view of a planar stacked fuel cell according to an embodiment of the present invention. FIG. 2 is a sectional view of the planar stacked fuel cell of FIG. As shown in these figures, the planar stacked fuel cell 1 is configured by arranging the fuel cells 2 formed in a substantially rectangular shape in a plan view in a plane.

  The membrane electrode structure 3 (3A to 3E) of each fuel cell 2 is formed by sandwiching a solid polymer electrolyte membrane (hereinafter simply referred to as an electrolyte membrane) 7 between an anode electrode 8 and a cathode electrode 9. The electrolyte membrane 7 is made of, for example, a perfluorosulfonic acid polymer. Each of the anode electrode 8 and the cathode electrode 9 includes a gas diffusion layer made of porous carbon cloth or porous carbon paper, and a catalyst layer made of an alloy mainly composed of Pt, and the surface of the catalyst layer contacts the electrolyte membrane 7. Let me.

In the electrolyte membrane 7, a plurality of communication holes 21a to 21f are formed on both outer sides of a portion where the electrodes 8, 9 are provided, and each of the communication holes 21a to 21f is formed with a reaction gas (fuel gas, oxidizing agent). Gas) and cooling medium supply and discharge ports. This will be described later.
Each of the membrane electrode structures 3 configured as described above is arranged along the longitudinal direction of the electrodes 8 and 9 so that the directions of the electrodes 8 and 9 adjacent to each other are different from each other.

The conductive separator sandwiching each of the membrane electrode structures 3 includes a first separator 4 having different reaction gas passages 10 and 11 and a second separator having only one of the passages 10 and 11. 5 is comprised.
The separator 5 (5A, 5B) has a planar shape formed into a rectangle having substantially the same size as the electrolyte membrane 7. Reactive gas passages (fuel gas passages, oxidizing gas passages) 10 and 11 are formed on the surfaces of the separators 5A and 5B facing the electrolyte membrane 7 at portions corresponding to the electrodes 8 and 9, respectively. The gas passage 10 facing the fuel gas passage 10 and the gas passage 11 facing the cathode electrode 9 serve as the oxidizing gas passage 11. In the separators 5A and 5B, communication holes 24a to 24f are formed at portions corresponding to the communication holes 21a to 21f of the electrolyte membrane 7.

  Further, the separator 4 is formed in a rectangular shape having the same size as the one in which the two separators 5, 5 are arranged at predetermined intervals in the direction along the gas passage. This predetermined interval is an interval at which the adjacent membrane electrode structures 3 are arranged. In the separator 4, a fuel gas passage 10 and an oxidizing gas passage 11 are formed at portions corresponding to the electrodes 8 and 9 of the adjacent membrane electrode structures 3 and 3, respectively. , 3 are formed with communication holes 22a to 22f, 23a to 23f at portions corresponding to the communication holes 21a to 21f, 21a to 21f. The separators 4 and 5 may be formed by bending a metal or by cutting carbon.

  The first separators 4, 4 formed in this way are arranged so as to sandwich the membrane electrode structure 3 so that different reaction gas passages 10, 11 face each other (arrows A, B in FIG. 1). ). Also, the second separator 5 is arranged on the other surface of the membrane electrode structures 3A, 3E in which the first separator 4 is arranged on only one surface such that the reaction gas passages 10, 11 face each other. The unit 12 is constituted. In other words, the second separators 5, 5 are used as the separators located at the start and end of the fuel cell 2 constituting the fuel cell 1.

  In this case, the first separator 4 is a common component of the fuel cells 2 and 2 adjacent to each other, so that the adjacent fuel cells 2 and 2 are electrically connected by the first separator 4. Can be connected to This eliminates the need for a special member for connecting the fuel cells 2 and 2, thereby reducing the work load and ensuring sufficient rigidity at the connection between the adjacent fuel cells 2 and 2. And the mountability can be improved.

  FIG. 4 is an explanatory diagram showing the flow of the reactant gas in the planar stacked fuel cell of FIG. The fuel gas 17 is supplied from the communication hole 24d of the separator 5B to the fuel gas passage 10 facing the anode 8 of the membrane electrode structure 3A via the communication hole 21d of the membrane electrode structure 3A and the communication hole 22a of the separator 4A. Then, the fluid flows from the communication hole 22a of the separator 4A toward the communication hole 22f. In the membrane electrode structures 3A and 3B adjacent to each other, the directions of the anode electrodes 8 are opposite to each other, and the anode electrodes 8 of the membrane electrode structures 3B face upward. For this reason, the fuel gas 17 flows from the communication hole 22f through the communication hole 21c of the membrane electrode structure 3A and the communication hole 24c of the separator 5B, and from the communication hole 22a of the adjacent separator 4B to the anode of the membrane electrode structure 3A. The fuel is supplied to a fuel gas passage 10 facing the electrode 8. In this way, the fuel gas 17 flows from the membrane electrode structures 3A to 3E so as to pass through the fuel gas passages 10 facing the respective anode electrodes 8. Similarly, the oxidizing gas 18 flows through the membrane electrode structures 3A to 3E so as to pass through the oxidizing gas passages 11 facing the respective cathode electrodes 9.

As described above, by supplying the fuel gas to the anode electrode 8 side and the oxidizing gas to the cathode electrode 9 side of each fuel cell 2, the fuel cell 2 is caused to generate power. That is, when a fuel gas is supplied to the electrode reaction surface of the anode electrode 8, hydrogen is ionized here and moves to the cathode electrode 9 via the electrolyte membrane 7. The electrons generated during this time are taken out to an external circuit via the terminals 14A and 14B and used as DC electric energy.
Here, different reaction gases (fuel gas and oxidizing gas) flow through the respective reaction gas passages 10 and 11 of the first separator 4, and the first separator 4 is connected to the fuel cell cells 2 adjacent to each other. , 2 can be connected in series, so that the adjacent fuel cells 2 can be connected in series, and the output voltage and output voltage can be increased.

In the present embodiment, the first separators 4 and 4 of each unit 12 are opposed to the second separators 5, and an insulating plate 6 is interposed between the first separators 4 and 4. The terminal 14 is interposed between the second separators 5 and stacked.
Thereby, the short circuit of each unit 12 can be prevented by the insulating plate 6, and the output voltage and output power obtained by each unit 12 can be obtained by electrically connecting the second separators 5, 5 via the terminals 14. Can be doubled by the number of layers. In addition, since the units 12 are electrically connected to each other and to the external circuit via the terminal 14, the units can be manufactured in the same shape regardless of the arrangement position, so that the mountability can be further improved.
Further, as shown in FIG. 3, by surrounding each unit 12 with the conductive casing 13, the rigidity of each unit 12 can be ensured and protection can be enhanced, thereby improving handling. be able to.

FIG. 5 is a perspective view showing a planar stacked fuel cell 1 of the present invention, and FIG. 6 is a perspective view showing a fuel cell formed by stacking conventional fuel cells. As shown in these drawings, in the planar stacked fuel cell 1 of the present embodiment, the stacked dimension (L1) of the plurality of stacked units 12... 12 is the height dimension (L2) of the conventional fuel cell. And a high output voltage and output power similar to the case where a plurality of fuel cells 2 are stacked can be obtained.
Therefore, the present invention can be suitably used when mounted on a vehicle or the like having a limited vehicle height, particularly when mounted under the floor of a driver's seat.

FIG. 7 is an explanatory diagram showing a flow of a reaction gas in a modification of the planar stack type fuel cell of FIG. FIG. 1 shows an example in which a reaction gas is individually circulated for each fuel cell 2. For example, the fuel gas 17 flowing through the fuel cell 2 including the separator 5B and the separator 4A passes through the communication hole 24d of the separator 5B through the communication hole 21d of the membrane electrode assembly 3A and the communication hole 22a of the separator 4A. The fuel gas is supplied to the fuel gas passage 10 facing the anode electrode 8 of the electrode structure 3A, flows from the communication hole 22a of the separator 4A toward the communication hole 22f, and is discharged outside without flowing to another fuel cell 2. . The flow path of the oxidizing gas of this fuel cell and the flow path of the fuel gas and the oxidizing gas flowing through the other fuel cells 2 are similarly configured.
When the configuration is such that the reaction gas is individually circulated for each fuel cell 2, the flow rate of the reaction gas can be adjusted for each fuel cell 2, so that the electrode reaction surface of each fuel cell 2 can be adjusted. A sufficient reaction gas can be supplied to the (anode electrode 8 and the cathode electrode 9), and a decrease in stoichiometry can be prevented.

  It is needless to say that the present invention is not limited to the contents of the above-described embodiment, and for example, the terminal 14 and the conductive casing 13 may not be provided. Further, in the embodiment, the case where the fuel cells are arranged in one row has been described.

1 is an exploded perspective view of a planar stacked fuel cell according to an embodiment of the present invention. FIG. 2 is an exploded cross-sectional view of the planar stack type fuel cell of FIG. 1. FIG. 4 is an exploded cross-sectional view illustrating a modification of the planar stacked fuel cell of FIG. 2. FIG. 2 is an explanatory diagram showing a flow of a reaction gas in the planar stacked fuel cell of FIG. 1. It is a perspective view showing the plane stack type fuel cell of the present invention. FIG. 9 is a perspective view showing a conventional fuel cell. FIG. 9 is an explanatory diagram showing a flow of a reaction gas in a modification of the planar stacked fuel cell of FIG. 1.

Explanation of reference numerals

REFERENCE SIGNS LIST 1 planar stacked fuel cell 2 fuel cell 3 membrane electrode structure 4 first separator 5 second separator 6 insulating plate 7 solid polymer electrolyte membrane 8 anode electrode 9 cathode electrode 10 fuel gas passage 11 oxidant gas passage 12 Unit 14 Terminal plate

Claims (4)

In a planar stacked fuel cell in which fuel cells having a membrane electrode structure formed by sandwiching an electrolyte membrane between a fuel electrode and an oxidant electrode are arranged in parallel in a plane,
A conductive separator that forms a reaction gas passage for supplying a reaction gas to the electrode of the membrane electrode structure is provided on one side with the reaction gas passage for the fuel electrode and the reaction gas passage for the oxidant electrode. A first separator, and a second separator provided with only one of the reaction gas passages,
Two first separators are arranged so as to sandwich the membrane electrode structure such that different reaction gas passages face each other, and the other surface of the membrane electrode structure in which the first separator is arranged only on one surface A planar stacked fuel cell, wherein a second separator is arranged so that the reaction gas passages thereof face each other to form a unit.   The units are stacked in the thickness direction to electrically connect the second separators of adjacent units in the stacking direction, and an insulating plate is interposed between the first separators of the adjacent units. The planar stacked fuel cell according to claim 1, wherein:   The planar stacked fuel cell according to claim 2, wherein the second separators between the adjacent units are electrically connected to each other via a terminal. A membrane electrode structure formed by sandwiching an electrolyte membrane between a fuel electrode and an oxidizer electrode is arranged in parallel in a plane,
A plurality of first separators having a plurality of reaction gas passages are arranged on both sides of each membrane electrode structure with different reaction gas passages facing each other,
On the other surface of the membrane electrode structure in which the first separator is disposed only on one surface, a plurality of units are provided in which a second separator having a single reaction gas passage is disposed to face,
The first separator and the second separator of each unit are opposed to each other, an insulating plate is interposed between the first separators, and a terminal is interposed between the second separators, and the units are stacked and arranged. A planar stacked fuel cell characterized by the above-mentioned.

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