JP2008282590A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a flow distribution characteristic of reaction gas in a power generation part of a fuel cell. <P>SOLUTION: The fuel cell 100 is equipped with a membrane electrode assembly 10 interposed between separators SP. The membrane electrode assembly 10 is equipped with a power generation part 11 including an electrolyte membrane 13; and two or more manifolds M3a to M3d, M4a to M4d for the same kind of reaction gas, installed along one side of the power generation part. A gas passage member 18 forming a reaction gas passage is arranged between the power generation part 11 of the membrane electrode assembly 10 and the separator SP. The gas passage member 18 is fixed to the separator SP with two or more joining portions CS. The Joining portions CP are unevenly arranged in the direction in which two or more manifold holes M3a to M3d, M4a to M4d are arranged to guide gas. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell.

  In a fuel cell, a membrane electrode assembly is usually sandwiched between two separators. On the outer periphery of the power generation section of the membrane electrode assembly, manifold holes are provided as through holes for supplying and discharging reaction gases (anode gas and cathode gas) to and from the power generation section where power generation is performed from the outside of the fuel cell. ing. The separator is provided with a gas flow path for guiding the reaction gas from the manifold hole to the power generation unit (Patent Document 1, etc.).

JP 2000-323149 A JP-A-2004-139825 JP-A-2002-503381 JP 2005-190745 A JP2000-1000045

  By the way, in order to improve the power generation efficiency of the fuel cell, it is preferable that the flow rate distribution of the reaction gas in the power generation unit is uniform. On the other hand, it is preferable to reduce the size of the fuel cell in order to arrange it in a limited space such as a vehicle, and the area where the manifold hole can be provided may be limited. In this case, there is a possibility that the gas flow rate in the power generation unit becomes non-uniform, for example, the reaction gas cannot be sufficiently supplied to the region of the power generation unit far from the manifold hole. However, in the past, the actual situation was that no sufficient ingenuity has been made for these problems.

  An object of this invention is to provide the technique which improves the distribution property of the reactive gas in the electric power generation part of a fuel cell.

  One aspect of the present invention is a fuel cell including a membrane electrode assembly sandwiched between two separators, the membrane electrode assembly including a power generation unit including an electrolyte membrane and one side of the power generation unit. A plurality of manifold holes of the same type for reaction gases provided in an array, and a gas flow that forms a reaction gas flow path between the power generation unit of the membrane electrode assembly and the separator. A passage member is disposed, and the gas flow path member is fixed to the separator by a plurality of joint portions, and the joint portions are non-uniformly arranged in the arrangement direction of the plurality of manifold holes. It is characterized by.

  According to this configuration, the flow rate distribution of the gas in the power generation unit can be changed depending on the distribution of the joint portions, and the gas distribution property in the power generation unit can be improved.

  The power generation unit includes a manifold hole region, which is a region where the plurality of manifold holes are projected when the plurality of manifold holes are projected along a direction toward one side of the power generation unit, and the plurality of manifold holes. A non-manifold hole region that is a non-projected region, and more joint sites may be provided in the manifold hole region than in the non-manifold hole region.

  According to this configuration, the flow rate of the gas flowing from the manifold hole region to the non-manifold hole region can be increased. Therefore, the gas distribution property in the power generation unit can be improved.

  The power generation unit has a junction site dense region where the junction sites are dense and a non-joint region where the junction site does not exist, and the junction site dense region is connected to the power generation unit from the plurality of manifold holes. It is good also as what is provided in the vicinity of the straight line which passes along the edge part of the said manifold hole when it sees along the direction which goes to one side.

  According to this configuration, since the gas flows from the junction site dense region to the non-joint region, the gas can be guided to a region having a low gas flow rate adjacent to the manifold hole. Therefore, the gas distribution property in the power generation unit can be improved.

  The plurality of manifold holes include first and second manifold holes adjacent to each other, and the junction site dense region includes first and second junction site dense regions, and the first and second junctions are provided. A first center line that passes through the center of the non-bonded region sandwiched between the region-concentrated regions and is perpendicular to the arrangement direction of the plurality of manifold holes is equidistant from each of the first and second manifold holes. It may be substantially overlapped with the second center line.

  According to this configuration, the gas is guided to the region of the power generation unit sandwiched between the first and second manifold holes when viewed vertically from the first and second manifold holes toward one side of the power generation unit. be able to. Therefore, the gas distribution property in the region can be improved.

  The joining portion may not be provided in a region including the catalyst layer on which the catalyst is supported in the power generation unit.

  According to this structure, it can prevent that a power generation area reduces by providing a junction part in the electric power generation part containing a catalyst layer. Therefore, the gas distribution property in the power generation unit can be improved while securing the power generation area.

  The present invention can be realized in various forms, for example, in the form of a fuel cell, a fuel cell system including the fuel cell, a vehicle equipped with the fuel cell system, and the like. .

A. First embodiment:
FIG. 1A is a schematic diagram showing the configuration of a fuel cell as an embodiment of the present invention. The fuel cell 100 is a polymer electrolyte fuel cell that receives supply of a fuel gas and an oxidizing gas (reactive gas) and generates power by an electrochemical reaction (fuel cell reaction). Specifically, hydrogen is supplied as an anode gas (fuel gas) to the anode electrode side of the membrane electrode assembly 10, and high-pressure air containing oxygen is supplied to the cathode electrode side as a cathode gas (oxidizing gas). The fuel cell 100 may not be a polymer electrolyte fuel cell, and the present invention can be applied to any of various types of fuel cells.

  The fuel cell 100 has a stack structure in which membrane electrode assemblies 10 and separators SP are alternately stacked. The separator SP includes a cathode plate SPc, an intermediate plate SPi, and an anode plate SPa. A cathode plate SPc is disposed on the cathode electrode side of the membrane electrode assembly 10, an anode plate SPa is disposed on the anode electrode side, and the intermediate plate SPi is sandwiched between two plates SPc and SPa.

  FIG. 1B is a perspective view showing a state in which the fuel cell 100 is fastened. The fuel cell 100 is fastened by the fastening member 20 while being sandwiched between the two end plates 21 and 22. The end plate 21 on the upper side in the stacking direction of the fuel cell 100 is provided with a through hole for connecting a manifold hole of the fuel cell 100 described later and a pipe outside the fuel cell 100, but the illustration is omitted. is there.

  The two end plates 21 and 22 are substantially rectangular members that substantially overlap the membrane electrode assembly 10 and the separator SP when viewed along the stacking direction of the fuel cell 100. The straight rod-shaped shaft portion 20s of the fastening member 20 passes through the two end plates 21 and 22 at a total of six locations, namely, the four corners CN of the two end plates 21 and 22 and the central portion SC of the two long sides facing each other. ing. Nut portions 20n are provided at both ends of the shaft portion 20s, and the fuel cell 100 receives a fastening load in the stacking direction by screwing the nut portion 20n.

  Note that the membrane electrode assembly 10 and the separator SP are provided with corner recesses CV1 at portions overlapping with the four corners CN of the end plates 21 and 22 when viewed in the stacking direction. A central recess CV2 is provided in a portion overlapping the SC. That is, the shaft portion 20s passes through the two end plates 21 and 22 through one of the two types of concave portions CV1 and CV2. As described above, the fuel cell 100 is reduced in size by the amount corresponding to the provision of the recesses CV1 and CV2 for disposing the fastening member 20.

  FIG. 2 is a schematic view showing a configuration of the membrane electrode assembly 10 on the anode electrode side. The configuration of the membrane electrode assembly 10 on the cathode electrode side is the same as that on the anode electrode side, and is not shown.

  The membrane electrode assembly 10 is a substantially rectangular member including a power generation unit 11 in which a fuel cell reaction is performed and an outer peripheral seal frame unit 12 surrounding the power generation unit 11. Two types of concave portions CV1 and CV2 for passing the shaft portion 20s of the fastening member 20 described above are provided in the four corners of the membrane electrode assembly 10 and the vicinity of the center of the two opposing long sides.

  The outer peripheral seal frame portion 12 is provided with manifold holes M1, M2, M3a to M3d, M4a to M4d, M5, and M6 which are through holes. The manifold hole M1 is responsible for supplying the anode gas, and the manifold hole M2 is responsible for discharging the anode exhaust gas containing hydrogen that has not been subjected to the reaction. The four manifold holes M3a to M3d are responsible for supplying cathode gas, and the four manifold holes M4a to M4d are discharges of cathode exhaust gas containing oxygen that has not been subjected to the reaction and moisture generated by the fuel cell reaction. Take on. The manifold hole M5 is responsible for supplying a refrigerant for cooling reaction heat generated by the fuel cell reaction, and the manifold hole M6 is responsible for discharging the refrigerant.

  The anode hole M1 for supplying anode gas and the manifold hole M5 for supplying refrigerant are provided along the same short side of the membrane electrode assembly 10. The same applies to the manifold hole M2 for discharging the anode gas and the manifold hole M6 for discharging the refrigerant. The manifold hole M1 and the manifold hole M2 are provided at diagonal positions across the power generation unit 11, and the manifold hole M5 and the manifold hole M6 are provided at diagonal positions across the power generation unit 11. Yes.

  Each of the four manifold holes M3a to M3d for supplying the cathode gas and the four manifold holes M4a to M4d for discharging the cathode exhaust gas are provided along the long sides facing each other with the power generation unit 11 in between. A central recess CV2 is provided between the two manifold holes M3a and M3b for supply and the two manifold holes M3c and M3d. Similarly, a central recess CV2 is also provided between the two manifold holes M4a and M4b for discharge and the two manifold holes M4c and M4d.

  On the surface of the outer peripheral seal frame portion 12, a seal line SL (illustrated by two lines) is provided so as to surround the manifold holes M <b> 1 to M <b> 6 and the power generation unit 11. The seal line SL is for preventing fluid leakage. The outer peripheral seal frame portion 12 can be formed of an insulating seal member such as silicon rubber.

  FIG. 3 is a cross-sectional view showing a cross section of the membrane electrode assembly 10 taken along the line 3-3 shown in FIG. 2, and shows a state of being sandwiched between two separators SP. The power generation unit 11 includes an electrolyte membrane 13 that exhibits good proton conductivity in a wet state. The electrolyte membrane 13 is sandwiched between the anode electrode layer 14a and the cathode electrode layer 14c. The electrolyte membrane 13 has a film end 13e which is an outer peripheral edge thereof protruding from the outer peripheral edges of the two electrode layers 14a and 14c. The film end portion 13 e is covered with the outer peripheral seal frame portion 12. As a result, the occurrence of cross leak in the vicinity of the film end 13e is suppressed. Here, “cross leak” refers to a phenomenon in which hydrogen on the anode electrode side moves to the cathode electrode side without being subjected to a reaction during power generation of the fuel cell.

  The two electrode layers 14 a and 14 c include a gas diffusion layer 15 and a catalyst layer 16. The gas diffusion layers 15 are provided on the surfaces of the two electrode layers 14 a and 14 c that do not contact the electrolyte membrane 13, respectively, and have a function of spreading the supplied reaction gas over the entire electrolyte membrane 13. The gas diffusion layer 15 can be composed of, for example, carbon paper. The catalyst layer 16 is provided by supporting a catalyst for promoting the fuel cell reaction on the surfaces of the two electrode layers 14a and 14c that are in contact with the electrolyte membrane 13. For example, platinum (Pt) can be employed as the catalyst. By the way, the power generation unit 11 includes a region where the catalyst layer 16 is provided on the two electrode layers 14 a and 14 c and a region where the catalyst layer 16 is not provided. The region where the catalyst layer 16 is provided is particularly called “main power generation section 11c” and is indicated by a broken line in FIG. In the power generation unit 11, the fuel cell reaction is actively performed particularly in the main power generation unit 11c.

  When the membrane electrode assembly 10 is sandwiched between the two separators SP, the gas flow path member 18 is disposed between the two electrode layers 14a and 14c and the separator SP. The gas flow path member 18 is disposed so as to cover the entire power generation unit 11, and is disposed so as to be in contact with both the two electrode layers 14 a and 14 c and the separator SP. The gas flow path member 18 has a function of spreading the reaction gas supplied to the whole of the two electrode layers 14a and 14c, and also has a function as a conductive path for the generated electricity. The gas flow path member 18 can be configured by a conductive porous member, a member obtained by processing a metal plate, and a plurality of through holes provided in a mesh shape.

  As shown in FIG. 3, the seal line SL provided in the outer peripheral seal frame portion 12 is provided as a protrusion 17 (lip), and is provided at a position facing each other on the anode electrode side and the cathode electrode side. The protrusion 17 realizes a sealing property by being pressed by the separator SP from both sides of the anode electrode side and the cathode electrode side.

  FIG. 4 is a schematic diagram showing the configuration of the anode plate SPa that constitutes the separator SP, and shows the surface side in contact with the intermediate plate SPi (FIG. 1A). In FIG. 4, when the fuel cell 100 is viewed along the stacking direction, a region overlapping the power generation unit 11 of the membrane electrode assembly 10 is indicated by a one-dot chain line, and a region overlapping the main power generation unit 11 c is indicated by a broken line. It is.

  The anode plate SPa is provided with manifold holes M1 to M6 and two types of recesses CV1 and CV2 in the same manner as the membrane electrode assembly 10 (FIG. 2). In the region of the power generation unit 11 of the anode plate SPa, an anode gas inflow hole P1 and an anode exhaust gas outflow hole P2 which are through holes are provided. The anode gas inflow hole P1 is provided across the long side of the power generation unit 11 between the main power generation unit 11c and the cathode gas supply manifold holes M3a to M3. Similarly, the anode exhaust gas outflow hole P2 is provided between the main power generation unit 11c and the cathode gas discharge manifold holes M4a to M4d. Through the anode gas inflow hole P1 and the anode exhaust gas outflow hole P2, the anode gas is supplied to and discharged from the power generation unit 11 on the anode electrode side of the membrane electrode assembly 10. A specific anode gas flow will be described later. The anode plate SPa can be made of a conductive member such as carbon or metal.

  FIG. 5 is a schematic diagram showing the configuration of the cathode plate SPc that constitutes the separator SP, and shows the surface side in contact with the membrane electrode assembly 10 (FIG. 1A). FIG. 5 is substantially the same as FIG. 4 except that a cathode gas inflow hole P3 and a cathode exhaust gas outflow hole P4 are provided instead of the anode gas inflow hole P1 and the anode exhaust gas outflow hole P2. In FIG. 5, a region that overlaps the two through holes P <b> 1 and P <b> 2 (FIG. 4) of the anode plate SPa when the fuel cell 100 is viewed along the stacking direction is indicated by a two-dot chain line.

  The cathode gas inflow hole P3 and the cathode exhaust gas outflow hole P4 are through holes provided in the region of the power generation unit 11. The cathode gas inflow hole P3 is provided across the long side of the power generation unit 11 between the cathode gas supply manifold holes M3a to M3d and the anode gas inflow hole P1. The cathode exhaust gas outflow hole P4 is provided across the long side of the power generation unit 11 between the cathode gas discharge manifold holes M4a to M4d and the anode exhaust gas outflow hole P2. Cathode gas is supplied to and discharged from the power generation unit 11 on the cathode electrode side of the membrane electrode assembly 10 through the cathode gas inflow hole P3 and the cathode exhaust gas outflow hole P4. A specific flow of the cathode gas will be described later.

  FIG. 6 is a schematic view showing the configuration of the intermediate plate SPi that constitutes the separator SP, and shows the side in contact with the cathode plate SPc (FIG. 1A). FIG. 6 is substantially the same as FIG. 5 except that each fluid flow path to be described later is provided and two through holes P3 and P4 and refrigerant manifold holes M5 and M6 are not provided. . In FIG. 6, when viewed along the stacking direction of the fuel cell 100, a region overlapping the refrigerant manifold holes M <b> 5 and M <b> 6 is indicated by a broken line, and through holes P <b> 1 provided in the two plates SPa and SPc are shown. A region overlapping P2, P3, and P4 is indicated by a two-dot chain line.

  The intermediate plate SPi is provided with two anode flow paths AP1 and AP2 penetrating through the long side direction of the power generation unit 11 for inducing the anode gas and the anode exhaust gas. The first anode flow path AP1 communicates with the manifold hole M1 for supplying anode gas, and is provided so as to substantially overlap the anode gas inflow hole P1 of the anode plate SPa. The second anode flow path AP2 communicates with the manifold hole M2 for anode exhaust gas, and is provided so as to substantially overlap the anode exhaust gas outlet hole P2 of the anode plate SPa.

  The intermediate plate SPi is provided with a plurality of supply cathode channels CP1 penetrating so as to form comb-like slits. The supply cathode channel CP1 has one end communicating with the cathode gas supply manifold holes M3a to M3d and the other end connected to the cathode gas inflow hole P3 of the cathode plate SPc. That is, the supply cathode channel CP1 is a channel that communicates the supply manifold holes M3a to M3d with the power generation unit 11 (FIG. 2) of the membrane electrode assembly 10. Similarly, the discharge cathode channel CP2 is provided in the intermediate plate SPi so that the manifold holes M4a to M4d and the power generation unit 11 communicate with each other.

  In the central portion of the intermediate plate SPi, a plurality of refrigerant flow paths WP are provided in parallel so as to connect the two refrigerant manifold holes M5 and M6 to each other. A part of the refrigerant supplied from the outside of the fuel cell 100 to the refrigerant supply manifold hole M5 flows into the refrigerant flow path WP of the intermediate plate SPi of each separator SP and moves toward the refrigerant discharge manifold hole M6 ( Arrow in FIG. 6). The refrigerant is discharged from the refrigerant discharge manifold hole M6 to the outside of the fuel cell 100 with heat generated by power generation. In addition, it is preferable that the refrigerant | coolant flow path WP is provided so that the whole electric power generation part 11 can be cooled.

  7A and 7B are schematic diagrams for explaining the flow of the anode gas in the fuel cell 100. FIG. FIGS. 7A and 7B are partial cross-sectional views of the fuel cell 100 taken along the sections 7A-7A and 7B-7B shown in FIG. The gas diffusion layer 15 and the catalyst layer 16 (FIG. 3) of the two electrode layers 14a and 14c are not shown for convenience of explanation.

  A part of the anode gas supplied from the outside of the fuel cell 100 to the manifold hole M1 flows into the first anode channel AP1 of the intermediate plate SPi as shown by an arrow in FIG. It passes through the anode gas inflow hole P1 of SPa and reaches the entire anode electrode layer 14a by the gas flow path member 18. On the other hand, the anode exhaust gas flows out from the anode exhaust gas outflow hole P2 of the anode plate SPa and passes through the second anode flow path AP2 of the intermediate plate SPi to the manifold hole M2 as shown by an arrow in FIG. 7B. The fuel cell 100 is discharged to the outside.

  FIG. 7C is a schematic diagram for explaining the flow of the anode gas in the fuel cell 100. FIG. 7C is a partial cross-sectional view of the fuel cell 100 taken along the 7C-7C section shown in FIG. The gas diffusion layer 15 and the catalyst layer 16 of the two electrode layers 14a and 14c are not shown for convenience of explanation.

  A part of the cathode gas supplied from the outside of the fuel cell 100 to the manifold holes M3a to M3d flows into the supply cathode channel CP1 of the intermediate plate SPi as shown by an arrow in FIG. Through the cathode gas inflow hole P3 of the plate SPc, the gas channel member 18 reaches the entire anode electrode layer 14a. On the other hand, the cathode exhaust gas flows out from the cathode exhaust gas outflow hole P4 of the cathode plate SPc as shown by the arrow in FIG. 7B, and passes through the discharge cathode channel CP2 of the intermediate plate SPi to the manifold holes M4a to M4d. To the outside of the fuel cell 100.

  FIG. 8 is an explanatory diagram for explaining the gas flow on the cathode electrode side. FIG. 8 shows the cathode electrode side of the membrane electrode assembly 10 in the fuel cell 100 during power generation with the separator not shown. FIG. 8 is substantially the same as FIG. 2 except that the gas flow path member 18 is disposed in the power generation unit 11. In FIG. 8, the cathode channels CP1 and CP2, the cathode gas inflow hole P3, and the cathode exhaust gas outflow hole P4 provided in the separator SP are indicated by broken lines.

  In the power generation unit 11, when the fuel cell 100 is viewed in the direction of arrow Y in the figure, a region that does not overlap with a region that overlaps the manifold holes M3a to M3d and M4a to M4d (referred to as “manifold hole region 11m”) (Referred to as “non-manifold hole region 11n”). As can be understood from the figure, when the manifold hole region 11m and the non-manifold hole region 11n are compared, the number of the cathode channels CP1 and CP2 connected to each of them is smaller in the non-manifold hole region 11n. . In the gas flow path member 18, most of the cathode gas flowing in from the supply cathode flow path CP <b> 1 normally flows to the discharge cathode flow path CP <b> 2 facing the power generation unit 11 as indicated by the arrows in the drawing. . Therefore, the flow rate of the cathode gas in the non-manifold hole region 11n tends to be smaller than the flow rate of the cathode gas in the manifold hole region 11m. The central non-manifold hole region 11nc sandwiched between the two central recesses CV2 is a region having a particularly low gas distribution property.

  Generally, in order to improve the power generation efficiency of the fuel cell, it is preferable that the flow rate distribution of the reaction gas in the power generation unit 11 is substantially uniform. However, not only in the fuel cell 100 but in the case where a plurality of manifold holes are formed on the outer periphery of the power generation unit 11, even if the porous flow path member is provided as in this embodiment, the power generation is performed as described above. The reaction gas flow rate distribution in the section 11 tends to be non-uniform. Therefore, in the present embodiment, the gas distribution property in the power generation unit 11 is improved as described below.

  FIG. 9 shows the cathode plate SPc after being assembled as the separator SP. FIG. 9 is substantially the same as FIG. 5 except that the gas flow path member 18 is disposed in the region of the power generation unit 11. 9 shows the central non-manifold hole region 11nc described in FIG. 8 in the same manner as in FIG. The gas flow path member 18 is similarly arranged on the anode plate SPa side, but the illustration is omitted.

  In the fuel cell 100 of the present embodiment, when assembled as a fuel cell, the gas flow path member 18 is fixed to the separator SP by spot welding. In addition, by fixing the gas flow path member 18 to the separator SP in this way, the gas flow path member 18 is used for positioning the separator SP and the membrane electrode assembly 10 when the fuel cell 100 is assembled. It can function as an indicator. However, the gas flow path member 18 may not have a function as an index for alignment.

  In FIG. 9, the joint part CS for spot welding is indicated by a black circle. The cathode gas supply side joining portion CS is preferably provided in a region between the main power generation unit 11c and the cathode gas inflow hole P3 and not overlapping the anode gas inflow hole P1. The reason why the joint portion CS is provided in a region that does not overlap with the two through holes P1 and P3 is to allow good energization during spot welding. Further, the reason why the joining site CS is not provided in the main power generation unit 11c is to prevent the power generation area of the main power generation unit 11c from being reduced by the joining site CS.

  The joint portions CS are densely provided in the vicinity of the boundary line of the central non-manifold hole region 11nc. Here, “near the boundary line of the central non-manifold hole region 11nc” means between the center ncc in the short side direction of the central non-manifold hole region 11nc and the center mc in the long side direction of the adjacent manifold hole M3b. Say the area. “Dense” refers to a state in which a plurality of joining sites CS are gathered to such an extent that a region where the plurality of joining sites CS exist and a region where the joining site CS does not exist can be distinguished at a glance. Similarly, a joint part CS is also provided on the cathode gas discharge side.

  FIG. 10 is a cross-sectional view showing a cross section of the three plates SPc, SPi, SPa and the gas passage member 18 on the cathode electrode side constituting the separator SP in the 10-10 cutting shown in FIG. The cross section is shown schematically. The gas flow path member 18 on the anode electrode side is not shown. As shown in the drawing, the porosity of the gas flow path member 18 decreases in the portion where the joint part CS of the gas flow path member 18 is provided in the thickness direction of the gas flow path member. Therefore, it is difficult for the gas to flow through the part where the joint part CS is provided.

  FIGS. 11A and 11B are schematic diagrams illustrating changes in the flow of the cathode gas due to the joining portion CS. 11A and 11B are enlarged views of the periphery of the supply manifold holes M3b and M3c and the discharge manifold holes M4b and M4c in FIG. 8, respectively, and a joining portion CS is added. As shown by the arrows in FIGS. 11A and 11B, the flow of the cathode gas changes by providing the joining portion CS. Specifically, since the amount of gas flowing in the direction of the arrow in the figure increases, the amount of gas flowing into the non-manifold hole region 11n increases and the flow distribution in the power generation unit 11 is improved.

  In addition, it is preferable to determine the joining part CS so that the gas flow is uniform by analyzing the gas flow in the power generation unit 11 in advance in the design stage of the fuel cell. Alternatively, the power generation distribution may be determined to be constant by analyzing the power generation distribution of the power generation unit 11. More specifically, the joining site CS can be provided at the following site.

  FIG. 12 is an explanatory diagram for explaining an installation site of the joint site CS, except that two regions CSa and CSn described later are shown instead of the central non-manifold hole region 11nc. ).

  As shown in the figure, the power generation unit 11 includes a joining region CSa that is a region where the joining parts CS are dense and a non-joining region that is a region where the joining part CS does not exist and is sandwiched between two joining regions CSa. CSn. At this time, the junction region CSa is provided so that the center line CSnc of the width of the non-joint region CSn extending in the long side direction of the power generation unit 11 substantially coincides with the center line Cbc between the two manifold holes M3b and M3c. It is good as what is done.

  In addition, the junction area | region CSa is good also as a area | region where the distribution density of junction site | part CS in the electric power generation part 11 is larger than another electric power generation area | region. Here, the “distribution density of the bonding sites CS” refers to the number of bonding sites CS present per unit area or the ratio of the area occupied by the bonding sites CS per unit area.

  As described above, according to the configuration of the present embodiment, the reaction gas can be guided to the region with poor flow distribution in the power generation unit 11 by the arrangement of the joint portion CS, and the flow of the reaction gas in the fuel cell is improved. Can be made.

B. Second embodiment:
FIG. 13 is a schematic view showing a configuration of a membrane electrode assembly 10A used in a fuel cell as a second embodiment of the present invention. FIG. 13 is substantially the same as FIG. 8 except that the shapes of the manifold holes M3a to M3d and M4a to M4d for the cathode gas are different from each other, and the flow of the gas is changed by providing the joint portion CS. . The joining part CS is provided in the same manner as in the first embodiment. The other configuration of the fuel cell of the second embodiment is the same as that described in the first embodiment.

  The manifold holes M3a to M3d and M4a to M4d for the cathode gas of the membrane electrode assembly 10A are connected to the manifold holes M3b, M3c, M4b and M4c adjacent to the central recess CV2, and the other manifold holes M3a, M3d, M4a and M4d. It is larger. By setting it as such a structure, the gas quantity itself supplied from the manifold holes M3b and M3c can be increased. Therefore, it is possible to increase the flow rate of the cathode gas flowing into the non-manifold hole region 11n sandwiched between the two central recesses CV2 by the joint portion CS.

  Thus, even when the shape and arrangement of the manifold holes are changed, the gas distribution property can be improved by the joint portion CS.

C. Third embodiment:
FIG. 14 is a schematic view showing a configuration of a membrane electrode assembly 10B used in a fuel cell as a third embodiment of the present invention. FIG. 14 is different from FIG. 14 in that the portion where the central recess CV2 is provided is different, the shape of the manifold holes M3a to M3d and M4a to M4d for cathode gas is different, and the display of the non-manifold hole region is different. It is almost the same as FIG. The other structure of the fuel cell of the third embodiment is the same as that described in the first embodiment.

  In this membrane electrode assembly 10B, the central concave portion CV2 is provided offset from the center of the long side direction of the power generation unit 11 in the opposite directions. Accordingly, the arrangement of the manifold holes is also configured as follows. The manifold holes M3b, M3c, M4b, and M4c adjacent to the central recess CV2 have two opposite manifold holes M3c and M4b and two opposite manifold holes M3b and M4c having the same size. Yes. Further, the two manifold holes M3b and M4c are provided smaller than the two manifold holes M3c and M4b. The remaining manifold holes M3a, M3d, M4a, and M4d are provided to have the same size. With such an arrangement of manifold holes, the flow rate of the gas flowing in the diagonal direction (arrow D in the figure) of the power generation unit 11 is increased, and the gas distribution in the central portion of the power generation unit 11 is improved. However, the gas flow rates in the non-manifold hole region 11ns on the cathode gas supply side and the non-manifold hole region 11ne on the discharge side shown in the figure are lower than in other regions.

  Therefore, in the third embodiment, the joint portions CS are provided close to each other in the vicinity of the two non-manifold hole regions 11ns and 11ne. Since the flow rate of the gas flowing in the direction of the arrow in the figure can be increased by the joint portion CS, the gas distribution property can be improved. As described above, the gas distribution property can be improved by changing the configuration of the manifold hole, and the gas distribution property can also be improved by the joint portion CS.

D. Fourth embodiment:
FIG. 15 is an explanatory diagram for explaining a joint portion CS in a fuel cell as a fourth embodiment of the present invention. FIG. 15 is substantially the same as FIG. 11A except that the position where the bonding site CS is provided is different. Since the discharge manifold hole side of the power generation unit 11 is the same, the illustration is omitted. The configuration of the fuel cell of the fourth embodiment is the same as that of the fuel cell 100 of the first embodiment except for the points described below.

  In the fourth embodiment, the joint parts CS are provided in a line so that the distance between the joint parts CS adjacent to each other increases as they approach the center in the short side direction of the central non-manifold hole region 11nc. By setting it as such a structure, since it becomes easy to flow gas, so that the center of the short side direction of the center non-manifold hole area | region 11nc is approached, the flow volume of the gas which flows into the direction of the arrow in a figure can be increased. Therefore, the flowability of the reaction gas in the power generation unit 11 can be improved.

E. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

E1. Modification 1:
The arrangement configuration of the joint portion CS described in the above embodiment is not limited to the configuration of the above embodiment, and various other configurations can be adopted. For example, the joint part CS may be provided more in the manifold hole region 11m than in the non-manifold hole region 11n. With such a configuration, the pressure loss per area of the manifold hole region 11m is increased more than that of the non-manifold hole region 11n due to the joining portion CS, and therefore gas flowing from the manifold hole region 11m to the non-manifold hole region 11n. The amount can be increased. That is, the joining part CS should just be arrange | positioned so that the electric power generation part 11 may become non-uniform distribution over the sequence direction of a some manifold hole.

E2. Modification 2:
In the above embodiment, the gas flow path member 18 and the separator SP are joined by spot welding, but may be joined by other methods. For example, brazing joining may be performed at the joining part CS. Moreover, the joining part CS does not need to have a substantially circular shape, and may have, for example, a substantially long side shape.

E3. Modification 3:
In the above embodiment, the cathode gas flow distribution is improved by the joint portion CS provided on the cathode electrode side. However, the anode gas flow may be improved by the joint portion CS on the anode electrode side as well.

E4. Modification 4:
In the above-described embodiment, the joint portions CS are provided on both the supply side and the discharge side of the reaction gas, but may be provided on only one of them. In this case, it is more preferable to provide on the discharge side. This is because the gas discharge performance is lowered due to the decrease in the porosity of the gas flow path member 18 on the discharge side, and the gas pressure in the main power generation unit 11c is increased, so that the power generation efficiency can be improved. Even when the gas discharge performance is lowered due to the joint portion CS, it is possible to suppress the drainage deterioration by securing the flow path cross-sectional area of the discharge-side cathode flow path CP2.

Schematic which shows the structure of a fuel cell. Schematic which shows the structure of a membrane electrode assembly. Sectional drawing which shows the partial cross section of a membrane electrode assembly. Schematic which shows the structure of the anode plate which comprises a separator. Schematic which shows the structure of the cathode plate which comprises a separator. Schematic which shows the structure of the intermediate | middle plate which comprises a separator. The schematic diagram for demonstrating the flow of the reactive gas in a fuel cell. The schematic diagram for demonstrating the flow of the reactive gas in the cathode electrode side. Schematic which shows the structure of the separator in 1st Example. The partial cross section figure for demonstrating the junction part of the separator in 1st Example. The schematic diagram for demonstrating the flow of the gas in 1st Example. Explanatory drawing for demonstrating the arrangement position of the joining site | part in 1st Example. The schematic diagram for demonstrating the structure of the membrane electrode assembly in 2nd Example, and the flow of gas. The schematic diagram for demonstrating the structure of the membrane electrode assembly in 3rd Example, and the flow of gas. The schematic diagram for demonstrating the arrangement position of the junction part in 4th Example, and the flow of gas.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Membrane electrode assembly 11 ... Power generation part 11c ... Main power generation part 11m ... Manifold hole area 11n ... Non-manifold hole area 11nc ... Central non-manifold hole area 11ne ... Non-manifold hole area on discharge side 11ns ... Supply side Non-manifold hole region 12 ... outer peripheral seal frame 13 ... electrolyte membrane 13e ... membrane end 14a ... anode electrode layer 14c ... cathode electrode layer 15 ... gas diffusion layer 16 ... catalyst layer 17 ... projection 18 ... gas flow path member 20 ... Fastening member 20n ... Nut part 20s ... Shaft part 21, 22 ... End plate 100 ... Fuel cell AP1 ... First anode flow path AP2 ... Second anode flow path CN ... Four corners CP1, CP2 ... Cathode flow path CS ... Joining Part CSa ... Junction region CSn ... Non-joint region CSnc ... Center line of non-joint region CV1 ... Corner recess CV2 ... Central recess Cbc ... Center line between manifold holes M1 to M6 ... Manifold hole P1 ... Anode gas inflow hole P2 ... Anode exhaust gas outflow hole P3 ... Cathode gas inflow hole P4 ... Cathode exhaust gas outflow hole SC ... Long side center part SL ... Seal line SP ... Separator SPa ... Anode plate SPc ... Cathode plate SPi ... Intermediate plate WP ... Refrigerant flow path mc ... Center of manifold hole ncc ... Center of non-manifold hole region

Claims (5)

A fuel cell comprising a membrane electrode assembly sandwiched between two separators,
The membrane electrode assembly is
A power generation unit including an electrolyte membrane;
A plurality of manifold holes of the same type for reaction gas provided arranged along one side of the power generation unit;
With
Between the power generation part of the membrane electrode assembly and the separator, a gas flow path member that forms a flow path of a reaction gas is disposed,
The gas flow path member is fixed to the separator by a plurality of joint portions,
The fuel cell according to claim 1, wherein the joining portions are non-uniformly arranged in an arrangement direction of the plurality of manifold holes. The fuel cell according to claim 1,
The power generation unit includes a manifold hole region, which is a region where the plurality of manifold holes are projected when the plurality of manifold holes are projected along a direction toward one side of the power generation unit, and the plurality of manifold holes. A non-manifold hole region that is a non-projected region,
The fuel cell is provided with a larger number of joint portions in the manifold hole region than in the non-manifold hole region. The fuel cell according to claim 1 or 2, wherein
The power generation unit has a junction site dense region where the junction sites are dense, and a non-joint region where the junction site does not exist,
The junction site dense region is provided in the vicinity of a straight line passing through an end of the manifold hole when viewed along a direction from the plurality of manifold holes toward one side of the power generation unit. The fuel cell according to claim 3, wherein
The plurality of manifold holes include first and second manifold holes adjacent to each other;
The junction site dense region includes first and second junction site dense regions,
A first center line that passes through the center of the non-joining region sandwiched between the first and second joining site dense regions and is perpendicular to the arrangement direction of the plurality of manifold holes is the first and second manifolds. A fuel cell that substantially overlaps a second centerline that is equidistant from each of the holes. The fuel cell according to any one of claims 1 to 4, wherein
The joining portion is not provided in a region including a catalyst layer on which a catalyst is supported in the power generation unit.

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