JP4429571B2 - Fuel cell separator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell separator structure in which a membrane electrode structure in which an anode electrode and a cathode electrode are arranged on both surfaces of an electrolyte membrane is sandwiched in the thickness direction.
[0002]
[Prior art]
In recent years, development of a fuel cell used for a power plant, a power source of an in-vehicle motor, and the like has been advanced. As this type of fuel cell, one having a structure in which unit cells provided with separators on both sides of a membrane electrode structure in which an anode electrode and a cathode electrode are joined on both sides of a solid polymer electrolyte membrane is known ( JP-A-5-109415).
FIG. 6 is a perspective view of a conventional fuel cell separator. The separator 100 shown in the figure has a structure in which a fuel gas plate 101 and an oxidant gas plate 102 sandwich an intermediate plate 103 provided between these plates 101, 102, and the fuel gas plate Reference numeral 101 denotes an anode electrode (not shown) of the membrane electrode structure, and the oxidant gas plate 102 is arranged to face a cathode electrode (not shown).
[0003]
Round through-holes 104 (104a to 104d) for flowing reaction gas (fuel gas, oxidant gas) are formed at the four corners of each plate 101 to 103, respectively, and one through-hole ( 104a and 104b) are communication holes for supplying and discharging the fuel gas, and the other through holes (104c and 104d) are communication holes for supplying and discharging the oxidant gas.
[0004]
The fuel gas plate 101 has a plurality of fuel gas supply grooves 105 formed along the plate 101 at a portion facing the anode electrode, and the oxidant gas plate 102 at a portion facing the cathode electrode. A plurality of oxidant gas supply grooves 106 are formed to be orthogonal to the fuel gas supply groove 105. The fuel gas supply groove 105 and the oxidant gas supply groove 106 have through portions 109 and 110 formed at both ends thereof.
A fuel gas manifold 107 and an oxidant gas manifold 108 are formed in the intermediate plate 103 so as to span the through portions 109 and 110 from the through holes 104a to 104d.
[0005]
In the separator 100, the fuel gas flows from the through hole 104 (for example, 104a) into the fuel gas manifold 107a of the intermediate plate 103, and is supplied to the fuel gas supply groove 105 from the through portion 109 connected to the manifold 107a. The The oxidant gas flows into the oxidant gas manifold 108c of the intermediate plate 103 from the through hole 104 (for example, 104d), and is supplied to the oxidant gas supply groove 106 from the through part 110 connected to the manifold 108c. . In this way, the fuel gas is supplied to the anode electrode, and the oxidant gas is supplied to the cathode electrode.
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional technique, the reaction gas (fuel gas, oxidant) is sequentially supplied from the supply grooves 105a and 106a formed on the upstream side of the manifolds 107a and 108a to the supply grooves 105e and 106e formed on the downstream side. Gas). For this reason, there is a possibility that the flow rates of the reaction gas flowing into the supply grooves 105 and 106 are different between the upstream side and the downstream side of the manifolds 107a and 108a. In this case, if sufficient reaction gas is not supplied to the supply grooves 105e and 106e formed on the downstream side of the manifolds 107a and 108a, there is a possibility that sufficient power generation may not be performed with the anode electrode and the cathode electrode in contact with these portions. was there.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a separator structure for a fuel cell that can be easily formed and can make a power generation reaction at an electrode uniform.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, the invention described in claim 1 is directed to a fuel gas flow path (for example, in an embodiment described later) on a surface facing an anode electrode (for example, an anode electrode 8 in the embodiment described later). A fuel gas plate (for example, a fuel gas plate 3 in an embodiment described later) provided with a fuel gas flow path 13) and an oxidant on a surface facing a cathode electrode (for example, a cathode electrode 9 in an embodiment described later). An oxidant gas plate (for example, an oxidant gas plate 4 in an embodiment to be described later) provided with a gas channel (for example, an oxidant gas channel 20 in an embodiment to be described later) and the plates are sandwiched between these plates. A separator for a fuel cell including an intermediate plate (for example, an intermediate plate 5 in an embodiment described later), In addition, at both end portions of the corresponding gas flow paths, long-hole-shaped through holes (for example, through holes 14 and 15 and through holes 21 and 22 in the embodiments described later) are formed in the width direction of the gas flow path. ) In the plane of each gas plate, and a pair of gas communication holes (for example, fuel gas communication holes 16 and 17 in the embodiments described later and with an oxidizing agent gas passage 18, 19) independently of the through hole, the intermediate plate, the fuel gas delivery passage passing fuel gas from the fuel gas passage in the through hole of the fuel gas flow field ( for example, oxidant gas and fuel gas delivery channel 27, 28) in the embodiment described below, and passes the oxidant gas from the oxidant gas passage in the through hole of the oxidant gas flow path Only pass channel (e.g., oxidizing agent gas delivery channel 29 and 30 in the embodiment described below) is characterized by having a a.
[0009]
According to the present invention, the fuel gas supplied to the communication hole corresponding to the fuel gas in the intermediate plate passes from the through hole connected to the flow path via the transfer flow path formed to communicate with the communication hole. It is supplied to and discharged from the fuel gas flow path. Further, the oxidant gas supplied to the communication hole corresponding to the oxidant gas in the intermediate plate is connected to the gas transfer flow path through a gas transfer flow path formed so as to communicate with the communication hole. The oxidant gas flow path is supplied and discharged from the through hole. Here, since each through hole is formed over the entire length in the width direction of the gas flow path, the delivered gas can be supplied and discharged substantially uniformly. Therefore, it becomes possible to distribute the reaction gas so as to extend from the respective through holes to the entire gas flow paths. Moreover, since each plate can be processed independently, it can form easily.
[0010]
The invention described in claim 2 is the invention described in claim 1, wherein each of the gas communication holes is formed in a long hole shape so as to face the corresponding through hole, and the major diameter direction of each gas communication hole Is a separator structure for a fuel cell, characterized in that it corresponds to the major axis direction of each corresponding through hole.
According to the present invention, since the communication hole is formed in a long hole shape so as to face the through hole, a large amount of reaction gas can be supplied to the gas flow path, and the long diameter direction of the communication hole corresponds to the above-mentioned. Since it corresponds to the major axis direction of the through hole, the reaction gas can be supplied and discharged substantially uniformly.
[0011]
A third aspect of the present invention is the fuel cell separator structure according to the first or second aspect, wherein each of the gas delivery passages includes a plurality of slits.
According to this invention, since the area | region in which the gas delivery flow path in the said intermediate plate is formed can be reduced, the rigidity of an intermediate plate can be improved.
[0012]
The invention described in claim 4 is the one described in any one of claims 1 to 3, wherein the gas delivery flow path is formed in a fan shape extending from each gas communication hole toward the through hole. This is a separator structure for a fuel cell.
[0013]
According to this invention, since the gas delivery flow path is formed in the fan shape, the width of the gas communication hole can be reduced, and the space efficiency is improved.
[0014]
Invention of Claim 5 is described in any one of Claim 1 to 4, Comprising: At least one part of the outer peripheral part of the said gas delivery flow path in the said intermediate plate is in the said gas plate. that is exposed from the position corresponding to the gas communication hole Ru Ah in separator over other fuel cell characterized by.
According to this invention, since the outer peripheral portion of the gas delivery channel in the intermediate plate is formed so as to be exposed from the position corresponding to the gas communication hole, the rigidity of the intermediate plate can be further increased, The exposed outer peripheral portion can be provided with a guide function for transferring the reaction gas between the gas communication hole and the through hole.
A sixth aspect of the present invention is the fuel cell according to any one of the first to fourth aspects, wherein a refrigerant flow path is provided in a plane of the intermediate plate. It is a separator.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a separator structure of a fuel cell according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a separator structure of a fuel cell according to a first embodiment of the present invention. As shown in the figure, the separator 1 in this embodiment has a structure including a fuel gas plate 3, an oxidant gas plate 4, and an intermediate plate 5 provided between these plates 3 and 4. ing. The three plates 3 to 5 are formed in a substantially square shape whose four corners are chamfered, and are formed so that the outer shapes are substantially the same when viewed from the stacking direction.
[0016]
The fuel gas plate 3 is disposed to face the anode electrode 8 (see FIG. 2) of the fuel cell 2 and supplies fuel gas (for example, hydrogen) to the anode electrode 8 as will be described in detail later. In the fuel gas plate 3, a substantially square fuel gas flow path 13 is formed at a portion in contact with the anode electrode 8. This fuel gas flow path 13 is formed into a corrugated plate shape by half-etching processing, and the entire length in the width direction of the fuel gas flow channel 13 is formed at both ends thereof by full etching processing (the total length in the direction crossing the corrugated portion). Through holes 14 and 15 are formed.
[0017]
The fuel gas plate 3 is formed with elongated gas communication holes 16 a to 19 a so as to surround the fuel gas flow path 13. Of these gas communication holes 16a to 19a, the fuel gas is supplied to and discharged from the communication holes 16a and 17a facing the through holes (both ends) 14 and 15 of the fuel gas passage 13 among the gas communication holes 16a to 19a. The oxidant gas is supplied to and discharged from the communication holes 18a and 19a.
[0018]
The oxidant gas plate 4 is disposed to face the cathode electrode 9 (see FIG. 2) of the fuel cell 2 and supplies oxidant gas (for example, air containing oxygen) as will be described in detail later. The oxidant gas plate 4 is formed with a substantially square oxidant gas flow path 20 at a portion in contact with the cathode electrode 9. The oxidant gas flow path 20 is formed in a corrugated plate shape by half-etching processing, like the fuel gas flow path 13, and the width of the oxidant gas flow path 20 is formed at both ends by full etching processing. Through holes 21 and 22 are formed over the entire length in the direction (over the entire length in the direction crossing the corrugated portion). The oxidant gas plate 4 is arranged so that the oxidant gas flow path 20 is orthogonal to the fuel gas flow path 13 of the fuel gas plate 3, and thereby the through holes 21 and 22 of the oxidant gas flow path 20 are formed. It is orthogonal to the through holes 14 and 15 of the fuel gas passage 13 when viewed from the stacking direction.
[0019]
The oxidant gas plate 4 is formed with elongated gas communication holes 16 b to 19 b so as to surround the oxidant gas flow path 20. These gas communication holes 16b to 19b are formed to have the same size at the same locations as the gas communication holes 16a to 19a when viewed from the stacking direction. In the oxidant gas plate 4, communication holes 18 b and 19 b are formed so as to face through holes (both ends) 21 and 22 of the oxidant gas flow path 20, and the remaining communication holes 16 b are orthogonal to these. , 17b are formed.
The communication holes 16 (16 a, 16 b) to 19 (19 a, 19 b) formed in the fuel gas plate 3 and the oxidant gas plate 4 have the major axis direction in the major axis direction of the respective through holes 14, 15, 21, 22. It is formed to match. As a result, as will be described in detail later, it becomes possible to supply and discharge the reaction gas to and from the through holes 14, 15, 21 and 22 substantially uniformly.
[0020]
In addition, gas delivery passages 27 to 30 are formed in the intermediate plate 5. The delivery passages 27 to 30 are for delivering the reaction gas between the gas communication holes 16 to 19 and the through holes 14, 15, 21, and 22. 16b) to 19 (19a, 19b) and the through holes 14, 15, 21, 22 are formed. In the present embodiment, the gas communication holes 16, 17 facing the through holes 14, 15 of the fuel gas flow path 13 become the fuel gas communication holes 16, 17 for supplying and discharging the fuel gas, and the oxidant gas flow path 20. The gas communication holes 18 and 19 facing the through holes 21 and 22 become the oxidant gas communication holes 18 and 19 for supplying and discharging the oxidant gas. The delivery channels 27 and 28 communicating with the fuel gas communication holes 16 and 17 become the fuel gas delivery channels 27 and 28, and the delivery channels 29 and 30 communicating with the oxidant gas communication holes 18 and 19 are oxidant gas. Delivery passages 29 and 30 are formed.
[0021]
In the present embodiment, each of the gas delivery channels 27 to 30 is formed from a plurality of slits. Thereby, since the area | region in which the gas delivery flow paths 27-30 in the said intermediate plate 5 are formed can be reduced, the rigidity of the intermediate plate 5 can be improved. In addition, these slits are formed in a fan shape extending from the communication holes 16 to 19 toward the through holes 14, 15, 21, and 22, and the outer peripheral portion of the slit is formed in the gas communication holes 16 to 19 in the gas plates 3 and 4. It is exposed from the corresponding position. Thereby, this exposed outer peripheral part can be provided with the guide function which delivers reaction gas between the communicating holes 16-19.
[0022]
The case where the separator 1 configured as described above is applied to a fuel cell will be described with reference to FIG. FIG. 2 is an exploded perspective view of a fuel cell using the separator 1 in which the plates 3 to 5 of FIG. 1 are stacked. As shown in this figure, the fuel cell 2 includes a pair of separators 1, 1, a membrane electrode structure (MEA) 6, and seal members 31 and 32 interposed therebetween. The membrane electrode structure 6 has a structure in which an anode electrode 8 and a cathode electrode 9 are integrated on both surfaces of a solid polymer electrolyte membrane 7.
[0023]
The solid polymer electrolyte membrane 7 is formed in a substantially square shape similar to that of the separator 1, and the bolt through hole 10 and the gas communication holes 16 to 19 are formed at the same location as the separator 1 when viewed from the stacking direction. Yes. Further, the electrodes 8 and 9 are formed in a substantially square shape across the positions facing the fuel gas flow path 13 and the oxidant gas flow path 20. Therefore, the separator 1 can form the fuel gas plate 3 and the oxidant gas plate 4 in the same shape. That is, in the present embodiment, the oxidant gas plate 4 can be formed by turning the fuel gas plate 3 upside down and rotating it 90 degrees. Thus, since the same shape can be used for each gas plate 3 and 4, a process and a formation process can be made easy. The shape of the plates 3 to 5 is not limited to this, and may be formed in a rectangular shape or a circular shape. Further, the corners need not be chamfered.
[0024]
The sealing members 31 and 32 interposed between the separator 1 and the membrane electrode structure 6 are also formed in a substantially square shape like the separator 1 and penetrate the bolt through the same part as the separator 1 when viewed from the stacking direction. Hole 10 and gas communication holes 16 to 19 are formed. Further, the seal members 31 and 32 have a shape in which portions corresponding to the electrodes 8 and 9 therein are cut out. Thereby, it is possible to arrange the electrodes 8 and 9 so as to contact the respective gas flow paths 13 and 20. In addition, rib portions 33 and 34 are formed on the surface of the seal members 31 and 32 facing the separators 1 and 1 around the above-described hollow portion and the gas communication holes 16 to 19. This enhances the rigidity of the seal members 31 and 32 and enhances the sealing function.
[0025]
The membrane electrode structure 6 is sandwiched between the separators 1 and 1 with the seal members 31 and 32 interposed therebetween, and the fuel cell 2 is held by passing bolts (not shown) through the respective bolt through holes 10. The In this state, the fuel cell 2 is caused to generate power by supplying and discharging the reaction gas to and from the communication holes 16 to 19.
3 is an AA arrow view shown in FIG. 1 in a state where the fuel cells of FIG. 2 are stacked. As shown in this figure, an oxidant gas 23 is supplied to the gas communication hole 18. The oxidant gas 23 is guided to the oxidant gas flow path 20 from the through hole 21 connected to the transfer flow path 29 via the transfer flow path 29.
[0026]
Further, the fuel gas 24 supplied to the gas communication hole 16 is also supplied to the fuel gas flow path 13 from the through hole 14 connected to the transfer flow path 27 via the transfer flow path 27. In this way, the fuel gas is supplied to the anode electrode 8 provided so as to be in contact with the fuel gas flow path 13, and the cathode electrode 9 provided so as to be in contact with the oxidant gas flow path 20 is oxidized. An agent gas is supplied, and an electrochemical reaction can be generated at these electrodes 8 and 9. The reaction gas flowing through the gas flow paths 13 and 20 is discharged from the other through holes 15 and 22 of the gas flow paths 13 and 20 to the communication holes 17 and 19 through the transfer flow paths 28 and 30. .
[0027]
In the present embodiment, since the through holes 14, 15, 21, 22 are formed over the entire length in the width direction of the gas flow paths 13, 20, the delivered gas can be supplied and discharged substantially uniformly. it can. As a result, the reaction gas can be circulated over the entire electrodes 8 and 9 with which the gas flow paths 13 and 20 are in contact, and the power generation efficiency can be increased. Power generation can be promoted and the rigidity of the separator 1 can be increased. In addition, by forming each slit in a fan shape that spreads from each gas communication hole toward the through hole, the reaction gas flowing through the gas communication holes 16 to 19 passes over the entire through holes 14, 15, 21, and 22. In this way, it is possible to flow in and the power generation can be further promoted.
[0028]
Next, the separator structure of the second embodiment will be described. In the present embodiment, members similar to those shown in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate. FIG. 4 is a schematic explanatory view showing a separator structure according to the second embodiment of the present invention.
[0029]
As shown in the figure, the separator 50 according to the present embodiment includes a cooling water communication hole in the fuel gas plate 52, the oxidant gas plate 53, and the intermediate plate 54 at the same position as viewed from the stacking direction. Two 55 are formed respectively. Further, the intermediate plate 54 is formed with a cooling water passage 56 having both ends of the communication hole 55 for cooling water, and allows the cooling water to flow through the cooling water passage 56. Further, the gas transfer passages 62 to 65 formed in the intermediate plate 54 are formed in the same shape in the portions overlapping with the gas communication holes 16 to 19 when viewed from the stacking direction, and the respective gas communication holes 16 to 19. Fan-shaped slits extending from the through holes 14, 15, 21, and 22 are formed. Thus, since the gas delivery passages 62 to 65 are formed in a fan shape, the width of the gas communication holes 16 to 19 can be reduced, and the area for forming the gas communication holes 16 to 19 can be reduced, so that the space efficiency is improved. To do. Thereby, it becomes possible to ensure the space which forms the cooling water communicating hole 55 etc. in each plate 52-54.
[0030]
FIG. 5 is an exploded perspective view of a fuel cell 51 using the separator structure of FIG. As shown in the figure, a cooling water communication hole 55 is also formed in the membrane electrode structure 60 and the seal members 58 and 59 at the same position as the separator 50. Further, in the seal members 58 and 59, the strength of the seal members 58 and 59 is improved by forming ribs 57 around the cooling water communication hole 55.
[0031]
As described above, the plate is made of stainless steel, aluminum or copper as the material of the plate constituting the separator. It is preferable to form a gas flow channel groove on the plate material by etching and to join the plates by thermocompression bonding. By doing in this way, the part which contacts a membrane electrode structure and a sealing member can ensure flatness, and can make electrical contact property and sealing performance high.
[0032]
In addition, a conductive surface treatment may be performed on a portion of the plate constituting the separator that contacts the electrode, and a non-conductive surface treatment may be performed on other portions. Thereby, power generation efficiency can be increased. Examples of the conductive surface treatment include plating with Pt, Pd, Au, Ar, Ru, Ir, sputtering, ion beam evaporation, and the like. Non-conductive surface treatment includes ceramic or resin coating treatment.
[0033]
In the embodiment, one intermediate plate is disposed between the fuel gas plate and the oxidant gas plate. However, the present invention is not limited to this, and two or more plates may be disposed. In addition, it is needless to say that the configuration of the embodiment can be changed without departing from the gist of the invention.
[0034]
【The invention's effect】
As described above, according to the first aspect of the present invention, the delivered gas can be supplied and discharged substantially uniformly. Therefore, it becomes possible to distribute the reaction gas so as to extend from the respective through holes to the entire gas flow paths. Moreover, since each plate can be processed independently, it can form easily.
[0035]
According to the second aspect of the invention, a large amount of reaction gas can be supplied to the gas flow path, and the reaction gas can be supplied and discharged substantially uniformly.
[0036]
Further, according to the invention described in claim 3, the rigidity of the intermediate plate, and thus the entire separator, can be increased.
Further, according to the invention described in claim 4, the width of the gas communication hole can be reduced, and the space efficiency in each plate can be improved.
[0037]
According to the invention described in claim 5, the rigidity of the intermediate plate can be further increased, and a guide function for transferring the reaction gas between the gas communication hole and the through hole by the exposed outer peripheral portion. Can be provided.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a separator structure of a fuel cell according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of a fuel cell using the separator of FIG.
3 is an AA arrow view of FIG. 1 in a state where the fuel cells of FIG. 2 are stacked.
FIG. 4 is an exploded perspective view of a separator structure of a fuel cell according to a second embodiment of the present invention.
5 is an exploded perspective view of a fuel cell using the separator structure of FIG.
FIG. 6 is an exploded perspective view of a conventional separator structure for a fuel cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Separator 2 Fuel cell 3 Fuel gas plate 4 Oxidant gas plate 5 Intermediate plate 8 Anode electrode 9 Cathode electrode 13 Fuel gas flow paths 14 and 15 Through holes 16 to 19 Gas communication holes 21 and 22 Through holes 23 to 26 Gas communication holes 27-30 Gas delivery channel

Claims (6)

A fuel gas plate having a fuel gas flow path on the surface facing the anode electrode, an oxidant gas plate having an oxidant gas flow path on the surface facing the cathode electrode, and an intermediate plate sandwiched between these plates; A fuel cell separator comprising:
Each gas plate is provided with a long through hole in the plane of each gas plate across the width direction of the gas flow channel at both ends of the corresponding gas flow channel in the thickness direction. A pair of gas communication holes that penetrate and supply and discharge each corresponding gas are provided independently of the through holes,
Said intermediate plate has a fuel gas delivery passage passing fuel gas from the fuel gas passage in the through hole of the fuel gas flow passage, the said oxidizing gas channel oxidant gas from the oxidant gas passage A separator for a fuel cell, comprising: an oxidant gas delivery channel that delivers to the through hole.   Each gas communication hole is formed in a long hole shape so as to face each corresponding through hole, and the major axis direction of each gas communication hole is coincident with the major axis direction of each corresponding through hole. The fuel cell separator according to claim 1.   3. The fuel cell separator according to claim 1, wherein each of the gas delivery passages includes a plurality of slits. 4.   4. The fuel cell separator according to claim 1, wherein each of the gas delivery passages is formed in a fan shape extending from each gas communication hole toward the through hole. 5.   5. The device according to claim 1, wherein at least a part of an outer peripheral portion of the gas delivery channel in the intermediate plate is exposed from a position corresponding to a gas communication hole in the gas plate. A separator for a fuel cell as described in 1.   The fuel cell separator according to any one of claims 1 to 5, further comprising a refrigerant flow path in a plane of the intermediate plate.

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