JP2008159291A - Fuel cell stack - Google Patents

Abstract

In a fuel cell stack including a stacked body in which a plurality of membrane electrode assemblies are stacked with separators interposed therebetween, the stacked body is fastened in the stacking direction and power generation efficiency is improved.
A fuel cell stack includes a plurality of air supply manifolds and a plurality of air discharge manifolds, and a first fastening member for fitting a first fastening member in a part between the plurality of air supply manifolds. A notch is provided, and a second notch for fitting the second fastening member is provided in a part between the plurality of air discharge manifolds. The first and second cutout portions are arranged at positions not facing each other, and both of the two air supply manifolds arranged with the first cutout portion interposed therebetween are at least one of any one air discharge manifold. Both of the two air discharge manifolds that are disposed at positions facing the section and sandwiching the second notch section are disposed at positions facing at least a part of any one of the air supply manifolds.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell stack including a laminate in which a plurality of membrane electrode assemblies are laminated with a separator interposed therebetween.

  A fuel cell that generates electricity by an electrochemical reaction between a fuel gas (for example, hydrogen) and an oxidant gas (for example, oxygen) has attracted attention as an energy source. Some fuel cells include a laminate in which a plurality of membrane electrode assemblies each having gas diffusion electrodes bonded to both surfaces of an electrolyte membrane are stacked with a separator interposed therebetween (hereinafter referred to as a fuel cell stack). Call).

  In such a fuel cell stack, a reaction gas supply manifold for branching and supplying the reaction gas supplied from the outside of the fuel cell stack to the outer peripheral portion of each membrane electrode assembly to each membrane electrode assembly, An off-gas discharge manifold is provided for collecting off-gas which is an unconsumed reaction gas in each membrane electrode assembly and discharging it to the outside of the fuel cell stack. A plurality of these may be provided depending on the shape of the fuel cell stack. Further, in the fuel cell stack, generally, the contact resistance between the membrane electrode assembly and the membrane electrode assembly and the separator is reduced, or the fluid (fuel gas, oxidant gas, cooling water) flowing in the fuel cell stack is reduced. In order to prevent leakage, a fastening load is applied in the stacking direction, and fastening is performed by a fastening member.

  Various techniques have been proposed for such a fuel cell stack. For example, a fuel cell stack described in Patent Document 1 below includes two reaction gas supply manifolds and two off-gases formed at positions facing each other across the membrane electrode assembly. Equipped with a discharge manifold. A through hole is provided between the two reaction gas supply manifolds and between the two off gas discharge manifolds. A tie rod is inserted into each through hole to tighten the fuel cell stack in the stacking direction. The structure is described.

JP-T-2005-524202

  However, in the technique described in Patent Document 1, through holes are formed between the two reaction gas supply manifolds and between the two off gas discharge manifolds, respectively, and therefore the distance between the two reaction gas supply manifolds. In some cases, the distance between the two off-gas discharge manifolds is naturally increased, and a region in which the reaction gas hardly flows is generated in the membrane electrode assembly. In the region where the reaction gas hardly flows, power generation is difficult to be performed, and the power generation efficiency of the fuel cell stack is reduced.

  The present invention has been made to solve the above-described problem, and in a fuel cell stack including a laminate in which a plurality of membrane electrode assemblies are stacked with a separator interposed therebetween, the laminate is fastened in the stacking direction. At the same time, it aims to improve the power generation efficiency.

  In order to solve at least a part of the above-described problems, the present invention employs the following configuration. The fuel cell stack of the present invention is a fuel cell stack including a laminate in which a plurality of membrane electrode assemblies are stacked with separators interposed therebetween, and the membrane electrode assemblies are mutually attached to some regions of the outer peripheral portion of the membrane electrode assembly. A plurality of reaction gas supply manifolds arranged adjacent to each other to supply a reaction gas supplied from the outside of the fuel cell stack to the plurality of membrane electrode assemblies, and an outer periphery of the membrane electrode assembly A plurality of the membrane electrode assemblies disposed adjacent to each other in a region facing the region where the plurality of reaction gas supply manifolds are arranged across the membrane electrode assembly, A plurality of off-gas discharge manifolds for collecting off-gas that is an unconsumed reaction gas and discharging it to the outside of the fuel cell stack, and a small amount between the plurality of reaction gas supply manifolds. A plurality of membrane electrode assemblies, and a first fastening member installation portion for installing a first fastening member for fastening the plurality of separators in the stacking direction; A second fastening member that is disposed at least in part between the off-gas discharge manifolds and that fastens the plurality of membrane electrode assemblies and the plurality of separators in the stacking direction. A fastening member installation part, wherein the first fastening member installation part is disposed at a position facing at least a part of the plurality of off-gas discharge manifolds, and the second fastening member installation part includes The gist is that it is arranged at a position facing at least a part of the plurality of reaction gas supply manifolds.

  In the fuel cell stack of the present invention, at least a part of the plurality of reaction gas supply manifolds is arranged with the first fastening member installation portion interposed therebetween. In addition, at least a part of the plurality of off-gas discharge manifolds is disposed with the second fastening member installation portion interposed therebetween. Therefore, the distance between the two reaction gas supply manifolds arranged with the first fastening member installation part interposed therebetween may be longer than the case where the first fastening member installation part is arranged without sandwiching the first fastening member installation part. In addition, the distance between the two off-gas exhaust manifolds arranged with the second fastening member installation part interposed therebetween may be longer than when the second fastening member installation part is arranged without sandwiching the second fastening member installation part. For this reason, when the first fastening member installation part and the second fastening member installation part are arranged at positions facing each other across the membrane electrode joint, in the membrane electrode assembly, the first fastening member installation part and In the region facing the second fastening member installation portion, there may be a region where the reaction gas is difficult to flow. In this case, in the region where the reaction gas in the membrane electrode assembly hardly flows, power generation is difficult to be performed, and power generation efficiency in the fuel cell stack is reduced.

  Therefore, in the present invention, the first fastening member installation portion is disposed at a position facing at least a part of the plurality of off-gas discharge manifolds with the membrane electrode joint interposed therebetween, and the second fastening member installation portion is disposed on the membrane electrode. It arrange | positions in the position which opposes at least one part of several reaction gas supply manifolds on both sides of joining. This makes it easier for the reaction gas to flow through the entire membrane electrode assembly as compared with the case where the first fastening member installation part and the second fastening member installation part are arranged at positions facing each other. be able to. Therefore, the effective power generation area in the membrane electrode assembly can be increased and the power generation efficiency can be improved. That is, according to the present invention, in the fuel cell stack, the stacked body can be fastened in the stacking direction and the power generation efficiency can be improved.

  In the fuel cell stack, the first fastening member installation portion and the second fastening member installation portion are arranged at positions that do not face each other across the membrane electrode assembly, and the plurality of reaction gases Of the supply manifolds, two reaction gas supply manifolds arranged with the first fastening member installation portion sandwiched therebetween are respectively at least part of any one of the plurality of offgas discharge manifolds. Two off-gas exhaust manifolds disposed across the second fastening member installation portion of the plurality of off-gas exhaust manifolds are arranged at opposite positions, respectively, of the plurality of reaction gas supply manifolds. It is arranged at a position facing at least a part of one of the reaction gas supply manifolds Door is preferable.

  By doing so, the reactive gas can easily flow through the entire membrane electrode assembly, the effective power generation area in the membrane electrode assembly can be increased, and the power generation efficiency can be improved.

  In any one of the above fuel cell stacks, the reaction gas supply manifold is an air supply manifold for branching and supplying air containing oxygen as the oxidant gas to the cathodes of the plurality of membrane electrode assemblies. Preferably, the off-gas discharge manifold is a cathode off-gas discharge manifold for collecting cathode off-gas that is unconsumed off-gas at the cathode and discharging it to the outside of the fuel cell stack. The reaction gas supply manifold is a hydrogen supply manifold for branching and supplying hydrogen as a fuel gas to the anodes provided in each of the plurality of membrane electrode assemblies, and the offgas discharge manifold is an unconsumed offgas at the anode. The anode off gas discharge manifold may be configured to collect and discharge the anode off gas to the outside of the fuel cell stack.

  In general, in a fuel cell stack, hydrogen is supplied to the anode as a fuel gas, and air containing oxygen is supplied to the cathode as an oxidant gas. Since each molecule contained in the air is larger than a hydrogen molecule, oxygen at the cathode is less likely to diffuse than hydrogen at the anode. According to the present invention, air as an oxidant gas can be easily supplied to the entire cathode, so that the effect of increasing the power generation efficiency by increasing the effective power generation area in the membrane electrode assembly is great.

  In any one of the above fuel cell stacks, at least one of the first fastening member installation portion and the second fastening member installation portion may be a cutout portion provided at least in the separator. Good. By carrying out like this, at least one of a 1st fastening member and a 2nd fastening member can be fitted to a notch part, and the said laminated body can be fastened. Note that at least one of the first fastening member installation part and the second fastening member installation part may be a through hole provided in at least the separator.

  In any one of the fuel cell stacks described above, the reaction gas and a porous member through which the off gas flows are interposed between the separator and the membrane electrode assembly from the reaction gas supply manifold to the off gas discharge manifold. You may make it wear. By doing so, gas can easily flow through the entire porous member.

Hereinafter, embodiments of the present invention will be described based on examples.
A. Fuel cell stack configuration:
FIG. 1 is a perspective view showing a schematic configuration of a fuel cell stack 100 as an embodiment of the present invention. This fuel cell stack 100 generally has a stack structure in which a plurality of membrane electrode assemblies each bonded with an anode and a cathode are laminated on both sides of an electrolyte membrane having proton conductivity with a separator interposed therebetween. ing. In this example, a solid polymer membrane was used as the electrolyte membrane. Another electrolyte such as a solid oxide may be used as the electrolyte. In this embodiment, the separator has a three-layer structure, as will be described later. In the separator, a flow path of hydrogen as a fuel gas to be supplied to the anode and an oxidation to be supplied to the cathode are provided. A flow path of air as the agent gas and a flow path of cooling water are formed. The number of membrane electrode assemblies stacked in the fuel cell stack 100 can be arbitrarily set according to the output required for the fuel cell stack 100.

  As shown in the figure, the fuel cell stack 100 is laminated from one end in the order of an end plate 10a, an insulating plate 20a, a current collecting plate 30a, a plurality of fuel cell modules 40, a current collecting plate 30b, an insulating plate 20b, and an end plate 10b. Is made up of. In the present embodiment, these have a horizontally long and substantially rectangular shape. The plurality of stacked fuel cell modules 40 correspond to the stacked body in the present invention. In the fuel cell stack 100, supply manifolds (hydrogen supply manifold, air supply manifold, cooling water supply manifold) for distributing and supplying hydrogen, air, and cooling water to the respective membrane electrode assemblies are provided. Also, an anode offgas and cathode offgas discharged from the anode and cathode of each membrane electrode assembly, and a discharge manifold for collecting cooling water and discharging it to the outside of the fuel cell stack 100 (anode offgas discharge manifold, cathode offgas) A discharge manifold and a cooling water discharge manifold) are formed.

  As shown in the figure, on the inner side of the lower long side of the end plate 10a, three air supply ports 12Ai, 12Bi, 12Ci constituting the air supply manifold are adjacent to each other along the lower long side. Is formed. Further, four cathode offgas discharge ports 12Ao, 12Bo, 12Co, 12Do constituting the cathode offgas discharge manifold are formed adjacent to each other along the upper long side inside the upper long side of the end plate 10a. Yes. Further, inside the left short side of the end plate 10a, a hydrogen supply port 14i constituting a hydrogen supply manifold and a cooling water supply port 16i constituting a cooling water supply manifold are formed adjacent to each other vertically. Yes. Further, on the right short side of the end plate 10a, a cooling water discharge port 16o constituting a cooling water discharge manifold and an anode off gas discharge port 14o constituting an anode off gas discharge manifold are formed adjacent to each other vertically. Yes.

  Hydrogen as a fuel gas is supplied to the hydrogen supply port 14i from a hydrogen tank (not shown), and the anode offgas discharged from the anode of the fuel cell stack 100 is discharged from the anode offgas discharge port 14o. Air containing oxygen as an oxidant gas compressed by an air compressor (not shown) is supplied to the air supply ports 12Ai, 12Bi, and 12Ci, respectively, and the cathode off-gas discharged from the cathode of the fuel cell stack 100 is the cathode It is discharged from the off-gas discharge ports 12Ao, 12Bo, 12Co. The cooling water supply port 16i is supplied with cooling water cooled by a radiator (not shown) and pressurized by a pump, flows through the fuel cell stack 100, is discharged from the cooling water discharge port 16o, and circulates. .

  The fuel cell module 40 includes a membrane electrode assembly, a unit that integrally includes a seal gasket, and a separator. The fuel cell module 40 will be described later.

  The end plates 10a and 10b are made of metal such as steel in order to ensure rigidity. The insulating plates 20a and 20b are formed of an insulating member such as rubber or resin. The current collecting plates 30a and 30b are formed of dense carbon, a gas impermeable conductive member such as a copper plate. The current collector plates 30a and 30b are provided with output terminals 32a and 32b, respectively, so that the power generated by the fuel cell stack 100 can be output.

B. tightening structure:
In the fuel cell stack 100, the plurality of fuel cell modules 40 and the like have a stack structure in order to suppress a decrease in cell performance due to an increase in contact resistance in any part of the stack structure or to prevent gas leakage. It is fastened in a state where a predetermined fastening load is applied in the laminating direction. Hereinafter, the fastening structure of the fuel cell stack 100 will be described.

  In this embodiment, the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and the plurality of fuel cell modules 40 are provided with cutout portions each having a rectangular shape. And these are made to contact | abut the square rod-shaped rod member 50 to each notch part, and apply the fastening load to the lamination direction of a stack structure, and both ends of each rod member 50 are made into the end plates 10a and 10b with the volt | bolt 52. It is fastened by fixing to each of the four corners. The shape of each notch portion viewed from the stacking direction is substantially the same as the cross-sectional shape of the rod member 50. Therefore, each rod member 50 does not protrude from the four corners of the end plates 10a and 10b.

  Note that the above-described fastening load in the fuel cell stack 100 is obtained by, for example, inserting a spacer between the end plate 10a and the insulating plate 20a, or between the end plate 10b and the insulating plate 20b. Or by adjusting the thickness of the insulating plates 20a and 20b. Further, since the length of the rod member 50 is defined in advance, the length in the stacking direction of the fuel cell stack 100 is constant regardless of the magnitude of the fastening load described above. Further, in the fuel cell stack 100 of the present embodiment, the rod members 50 are respectively brought into contact with the respective notches provided at the four corners of the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and the plurality of fuel cell modules 40. By doing so, each positioning can be performed.

  Further, in the fuel cell stack 100 of the present embodiment, the end plate 10a, the end plate 10b, the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and a cutout portion at the center of the upper side surface of the plurality of fuel cell modules 40. (For example, the notch 17a in the illustrated end plate 10a) is formed. Further, the end plate 10a, the end plate 10b, the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and the lower side surfaces of the plurality of fuel cell modules 40 are opposed to the notch portions formed on the upper side surface. Two notches (for example, notches 18a and 19a in the illustrated end plate 10a) are formed at positions where they are not. As shown in the figure, the notches 18a and 19a in the end plate 10a are disposed at positions facing the cathode off-gas exhaust ports 12Bo and 12Co, respectively, and the notch 17a in the end plate 10a is air. It arrange | positions in the position facing supply port 12Bi.

  Then, the fastening member 60 is fitted into the notch formed on the upper side surface of the fuel cell stack 100, and both ends of the fastening member 60 are fixed to the end plates 10a and 10b by bolts 62, respectively. Fastening members 70 and 80 are respectively fitted in two notches formed on the lower side surface of the fuel cell stack 100, and both end portions of the fastening members 70 and 80 are illustrated in the end plates 10a and 10b, respectively. Do not fasten with bolts. By doing so, it is possible to prevent the end plates 10a and 10b from being bent and deformed by the reaction force of the fastening load described above.

  The shape of the notch formed on the upper side surface of the fuel cell stack 100 as viewed from the stacking direction is substantially the same as the cross-sectional shape of the fastening member 60, and is formed on the lower side surface of the fuel cell stack 100. The shapes of the two notches as viewed from the stacking direction are substantially the same as the cross-sectional shapes of the fastening members 70 and 80, respectively. Therefore, the fastening members 60, 70, 80 do not protrude from the side surfaces of the fuel cell stack 100. The two notches formed on the lower side surface of the fuel cell stack 100, and the fastening members 70 and 80 fitted and fixed to these notches are respectively the first fastening members in the present invention. It corresponds to an installation part and a first fastening member. Further, the notch portion formed on the upper side surface of the fuel cell stack 100, and the fastening member 60 fitted and fixed to the notch portion, respectively, the second fastening member installation portion in the present invention, and This corresponds to the second fastening member.

  The rod member 50 and the fastening members 60, 70, 80 are made of metal such as steel in order to ensure rigidity. These surfaces are coated with an insulating film in order to ensure insulation between the fuel cell modules 40 and between the fuel cell module 40 and the end plates 10a and 10b.

C. Fuel cell module configuration:
Each fuel cell module 40 constituting the fuel cell stack 100 has both sides of a unit (hereinafter referred to as a seal gasket-integrated MEA) in which a seal gasket is disposed around a membrane electrode assembly (MEA), which will be described later. It is comprised by pinching with the separator 41 which carries out. In this example, the membrane / electrode assembly has a catalyst layer and a gas diffusion layer bonded to one surface of the electrolyte membrane as a cathode, and a catalyst layer and a gas diffusion layer as an anode on the other surface. The layers are joined. Hereinafter, the seal gasket-integrated MEA 46 and the separator 41 will be described.

C1. Seal gasket integrated MEA:
FIG. 2 is an explanatory view showing a schematic structure of the seal gasket-integrated MEA 46. FIG. 2A shows a plan view of the seal gasket-integrated MEA 46 as viewed from the cathode side. FIG. 2B shows a cross-sectional view taken along the line AA in FIG.

  As shown in FIG. 2A, the seal gasket-integrated MEA 46 has a substantially rectangular shape, and a seal gasket 460 made of silicone rubber is integrally formed around the MEA 461 having a rectangular shape. . As shown in FIG. 2B, the MEA 461 is obtained by bonding a cathode 461c and an anode 461a to both surfaces of the electrolyte membrane 461m, respectively. Then, as shown in FIG. 2A, notches 460c with which the rod member 50 described above abuts are formed at the four corners of the seal gasket 460, respectively. Further, a notch 467 is formed at the center of the upper long side of the seal gasket 460 and at a position corresponding to the notch 17a formed in the end plate 10a. Further, the lower long side of the seal gasket 460 is a position that does not face the notch portion 467 and that corresponds to the notch portion 18a formed in the end plate 10a and the notch portion 19a. Two notches 468 and 469 are formed. In this embodiment, silicone rubber is used as the seal gasket 460. However, the present invention is not limited to this, and other members having gas impermeability, elasticity, and heat resistance may be used.

  In the region near the MEA 461 on the lower long side portion of the seal gasket 460, air supply through holes 462Ai, 462Bi, 462Ci constituting the air supply manifold are arranged along the lower long side of the seal gasket 460. Adjacent to each other. The formation positions of the air supply through holes 462Ai, 462Bi, 462Ci in the seal gasket 460 correspond to the formation positions of the air supply ports 12Ai, 12Bi, 12Ci formed in the end plate 10a, respectively. As shown in the figure, the notch 468 is formed between the air supply through hole 462Ai and the air supply through hole 462Bi, and the notch 469 is formed in the air supply through hole 462Bi. And the air supply through hole 462Ci.

  Further, in the vicinity of the MEA 461 on the upper long side of the seal gasket 460, cathode off gas discharge through-holes 462Ao, 462Bo, 462Co, 462Do, which constitute the cathode off gas discharge manifold, extend along the upper long side of the seal gasket 460. Are formed adjacent to each other. The formation positions of the cathode offgas discharge through holes 462Ao, 462Bo, 462Co, 462Do in the seal gasket 460 correspond to the formation positions of the cathode offgas discharge ports 12Ao, 12Bo, 12Co, 12Do, respectively. As shown in the figure, the notch 467 is formed between the cathode offgas discharge through hole 462Bo and the cathode offgas discharge through hole 462Co.

  In the seal gasket-integrated MEA 46, the air supply through-hole 462Ai, the air supply through-hole 462Bi, and the air supply through-hole arranged with the notch 469 interposed therebetween. As shown in the drawing, the hole 462Bi and the air supply through hole 462Ci are disposed at positions facing at least a part of the cathode off gas discharge through holes 462Ao, 462Bo, 462Co, and 462Do, respectively. Further, the cathode off-gas discharge through-hole 462Bo and the cathode off-gas discharge through-hole 462Co arranged with the notch 467 interposed therebetween are at least one of the air supply through-holes 462Ai, 462Bi, and 462Ci, respectively, as shown in the figure. It is arrange | positioned in the position facing a part.

  Further, in a region near the MEA 461 on the left short side portion of the seal gasket 460, a hydrogen supply through-hole 464i constituting a hydrogen supply manifold and a cooling water supply through-hole 466i constituting a cooling water supply manifold are vertically arranged. Are arranged and formed. The formation positions of the hydrogen supply through hole 464i and the cooling water supply through hole 466i in the seal gasket 460 correspond to the formation positions of the hydrogen supply port 14i and the cooling water supply port 16i formed in the end plate 10a, respectively. is doing.

  Further, in the region near the MEA 461 on the right short side portion of the seal gasket 460, there are a cooling water discharge through hole 466o constituting the cooling water discharge manifold and an anode off gas discharge through hole 464o constituting the anode off gas discharge manifold. The upper and lower parts are arranged. The formation positions of the cooling water discharge through hole 466o and the anode off gas discharge through hole 464o in the seal gasket 460 are the formation positions of the cooling water discharge port 16o and the anode off gas discharge port 14o formed in the end plate 10a, respectively. It corresponds to.

  Further, as shown in FIG. 2B, the seal gasket 460 is formed with line-shaped protrusions on both sides of the above-described through holes and the MEA 461 so as to seal the seal gasket 460. Each line SL is formed. When the seal gasket-integrated MEA 46 and the separator 41 described later are stacked by the seal line SL, hydrogen flowing in each of the above-described through holes, air, cooling water, hydrogen flowing on the surface of the MEA 461, Leakage to the outside of the air can be suppressed.

C2. Separator:
FIG. 3 is a plan view of components of the separator 41. In this embodiment, the separator 41 includes three metal flat plates each having a plurality of through holes, that is, a cathode facing plate 42, an intermediate plate 43, an anode facing plate 44, and a cooling water flow in the separator 41. It is comprised from the cooling water flow-path formation member 45 for forming a path | route. The separator 41 is produced by sandwiching the intermediate plate 43 and the cooling water flow path forming member 45 between the cathode facing plate 42 and the anode facing plate 44 and hot-pressing them. In the present embodiment, the cathode facing plate 42, the intermediate plate 43, and the anode facing plate 44 are made of stainless steel flat plates having substantially the same rectangular shape as the seal gasket integrated MEA 46. The cooling water flow path forming member 45 is also made of stainless steel. As the cathode facing plate 42, the intermediate plate 43, the anode facing plate 44, and the cooling water flow path forming member 45, a flat plate made of another metal such as titanium or aluminum may be used instead of stainless steel. Further, as the intermediate plate 43, a resin plate may be used.

  FIG. 3A is a plan view of the cathode facing plate 42 in contact with the cathode side surface of the seal gasket-integrated MEA 46. A region surrounded by a broken line in the drawing represents a region corresponding to the MEA 461 in the seal gasket-integrated MEA 46 described above.

  As shown in the drawing, at the four corners of the cathode facing plate 42, similarly to the seal gasket-integrated MEA 46, notches 42 c with which the rod member 50 described above abuts are formed. The cathode facing plate 42 is provided with air supply through holes 422Ai, 422Bi, 422Ci constituting the air supply manifold and a cathode off-gas discharge manifold at positions corresponding to the through holes formed in the seal gasket-integrated MEA 46. The cathode off-gas discharge through-holes 422Ao, 422Bo, 422Co, 422Do, the hydrogen supply through-hole 424i constituting the hydrogen supply manifold, the cooling water supply through-hole 426i constituting the cooling water supply manifold, and the cooling water discharge A cooling water discharge through hole 426o constituting the manifold and an anode off gas discharge through hole 424o constituting the anode off gas discharge manifold are formed. The shape of each of these through holes is the same as the shape of each of the corresponding through holes in the seal gasket-integrated MEA 46.

  Further, a cutout portion 427 is formed at a central portion of the upper long side of the cathode facing plate 42 at a position corresponding to the cutout portion 467 formed in the seal gasket integrated MEA 46. Further, the lower long side of the cathode facing plate 42 is a position not facing the notch 427 and corresponds to the notch 468 and the notch 469 formed in the seal gasket-integrated MEA 46, respectively. Two notches 428 and 429 are formed at the positions where they are located.

  Further, as shown in the figure, the cathode facing plate 42 includes a plurality of air supply ports 422hi disposed at positions facing the lower end of the MEA 461 in the vicinity of the air supply through holes 422Ai, 422Bi, 422Ci, and a cathode off gas discharge. A plurality of cathode offgas discharge ports 422ho are formed at positions facing the upper end of the MEA 461 in the vicinity of the through holes 422Ao, 422Bo, 422Co, 422Do. In this embodiment, the plurality of air supply ports 422hi and the plurality of cathode offgas discharge ports 422ho are all circular with the same diameter.

  FIG. 3B is a plan view of the intermediate plate 43. A region surrounded by a broken line in the drawing represents a region corresponding to the MEA 461 in the seal gasket-integrated MEA 46 described above.

  As shown in the drawing, at the four corners of the intermediate plate 43, similarly to the seal gasket-integrated MEA 46, notches 43 c with which the rod members 50 described above are in contact are formed. The intermediate plate 43 includes air supply through holes 432Ai, 432Bi, and 432Ci that constitute an air supply manifold, and cathode offgas discharge manifolds at positions corresponding to the through holes formed in the seal gasket-integrated MEA 46. Cathode off-gas discharge through-holes 432Ao, 432Bo, 432Co, 432Do, a hydrogen supply through-hole 434i constituting a hydrogen supply manifold, a cooling water supply through-hole 436i constituting a cooling water supply manifold, and a cooling water discharge manifold The cooling water discharge through hole 436o and the anode off gas discharge through hole 434o forming the anode off gas discharge manifold are formed. The shape of each of these through holes is the same as the shape of each of the corresponding through holes in the seal gasket-integrated MEA 46.

  Further, a notch 437 is formed at the center of the upper long side of the intermediate plate 43 and at a position corresponding to the notch 467 formed in the seal gasket-integrated MEA 46. Further, the lower long side of the intermediate plate 43 is a position that does not face the notch 437 and corresponds to the notch 468 and the notch 469 formed in the seal gasket-integrated MEA 46, respectively. Two notches 438 and 439 are formed at the positions.

  Further, in the intermediate plate 43, the air supply through holes 432Ai, 432Bi, and 432Ci are respectively connected to the plurality of air supply ports 422hi formed in the cathode facing plate 42 from the air supply through holes 432Ai, 432Bi, and 432Ci. A plurality of air supply flow path forming portions 432Aip, 432Bip, and 432Cip are provided for flowing air. Further, the cathode off gas discharge through holes 432Ao, 432Bo, 432Co, 432Do are connected to the cathode off gas discharge through holes 432Ao, 432Bo, 432Co, 432Do from the plurality of cathode off gas discharge ports 422ho formed in the cathode facing plate 42, respectively. A plurality of cathode offgas discharge flow path forming portions 432Aop, 432Bop, 432Cop, and 432Dop for respectively flowing the cathode offgas are provided. Further, the hydrogen supply through hole 434i has a plurality of hydrogen supply flows for flowing hydrogen from the hydrogen supply through hole 434i to a plurality of hydrogen supply ports 444hi formed in the anode facing plate 44 described later. A path forming part 434ip is provided. The anode off gas discharge through hole 434o has a plurality of anode off gases for flowing the anode off gas from a plurality of anode off gas discharge ports 444ho formed in the anode facing plate 44 described later to the anode off gas discharge through hole 434o. A discharge flow path forming portion 434op is provided.

  In addition, a cooling water supply through hole 436 i and a cooling water discharge through hole 436 o are connected to an area of the intermediate plate 43 corresponding to almost the entire MEA 461 in the seal gasket-integrated MEA 46. A cooling water flow part 435 which is a through hole serving as a path is formed. The cooling water flow part 435 is formed inside the cooling water flow portion 435 so that the cooling water flows from the cooling water supply through hole 436i to the cooling water discharge through hole 436o. A corrugated cooling water flow path forming member 45 having a continuous rectangular uneven cross-sectional shape is disposed. The dimension in the thickness direction of the cooling water flow path forming member 45 is the same as the thickness of the intermediate plate 43. When the separator 41 is manufactured, the cathode facing plate 42 and the anode facing plate 44 are hot together with the intermediate plate 43. Press bonded.

  FIG. 3C is a plan view of the anode facing plate 44 that comes into contact with the surface on the anode side of the seal gasket-integrated MEA 46. A region surrounded by a broken line in the drawing represents a region corresponding to the MEA 461 in the seal gasket-integrated MEA 46 described above.

  As shown in the drawing, at the four corners of the anode facing plate 44, similarly to the seal gasket-integrated MEA 46, notches 44 c with which the rod members 50 described above are in contact are formed. The anode facing plate 44 is provided with air supply through-holes 442Ai, 442Bi, 442Ci and a cathode off-gas discharge manifold constituting the air supply manifold at positions corresponding to the respective through-holes formed in the seal gasket-integrated MEA 46. The cathode off-gas discharge through-holes 442Ao, 442Bo, 442Co, 442Do, the hydrogen supply through-hole 444i constituting the hydrogen supply manifold, the cooling water supply through-hole 446i constituting the cooling water supply manifold, and the cooling water discharge A cooling water discharge through hole 446o constituting the manifold and an anode off gas discharge through hole 444o constituting the anode off gas discharge manifold are formed. The shape of each of these through holes is the same as the shape of each of the corresponding through holes in the seal gasket-integrated MEA 46.

  Further, a notch 447 is formed at the center of the upper long side of the anode facing plate 44 at a position corresponding to the notch 467 formed in the seal gasket integrated MEA 46. Further, the lower long side of the anode facing plate 44 is a position not facing the notch 447 and corresponds to the notch 468 and the notch 469 formed in the seal gasket-integrated MEA 46, respectively. Two notches 448 and 449 are formed at the positions where they are located.

  Further, as shown in the figure, the anode facing plate 44 includes a plurality of hydrogen supply ports 444hi arranged at positions facing the left end of the MEA 461 in the vicinity of the hydrogen supply through-hole 444i, and the vicinity of the anode off-gas discharge through-hole 444o. A plurality of anode off-gas discharge ports 444ho are formed at positions facing the right end of the MEA 461. In this embodiment, the plurality of hydrogen supply ports 444hi and the plurality of anode offgas discharge ports 444ho are all circular with the same diameter.

  In the fuel cell module 40 of this embodiment, when the seal gasket-integrated MEA 46 and the separator 41 are stacked, the hydrogen supplied from the hydrogen supply manifold or the air supply manifold is supplied between the MEA 461 and the separator 41. As a gas flow path layer constituting a gas flow path for supplying the air to the anode 461a and the cathode 461c of the MEA 461, a metal porous body layer made of a metal porous body is interposed, respectively. As the gas flow path layer, other members having conductivity and gas diffusibility such as carbon may be used instead of the metal porous body.

  FIG. 4 is a plan view of the separator 41. As described above, in the separator 41, the cooling water flow path forming member 45 is disposed in the cooling water flow portion 435 of the intermediate plate 43, the cathode facing plate 42, the anode facing plate 44, and the intermediate plate. 43 is formed by hot press bonding. Here, the state seen from the anode facing plate 44 side is shown.

C3. Cross-sectional structure of the fuel cell module:
FIG. 5 is an explanatory view showing a cross-sectional structure of the fuel cell module 40. The AA sectional view in FIG. 4 when the separator 41 and the seal gasket-integrated MEA 46 are laminated is shown.

  In the seal gasket-integrated MEA 46, the metal porous body layer 47 on the anode side of the MEA 461 is disposed so as to contact the anode facing plate 44 of the separator 41 when the seal gasket-integrated MEA 46 and the separator 41 are laminated. ing. Further, the metal porous body layer 47 on the cathode side of the MEA 461 is disposed so as to contact the cathode facing plate 42 of the separator 41 when the seal gasket-integrated MEA 46 and the separator 41 are laminated. Further, the seal line SL formed in the seal gasket 460 comes into contact with the cathode facing plate 42 and the anode facing plate 44.

  As indicated by the arrows in the figure, in the fuel cell module 40, the air supplied from the air supply through hole 442 Bi of the anode facing plate 44 branches from the air supply through hole 432 Bi of the intermediate plate 43, The gas is supplied in a direction perpendicular to the surface of the MEA 461 from the air supply port 422hi of the cathode facing plate 42 through the supply flow path forming unit 432Bip. The air flows while diffusing in the metal porous body layer 47 on the cathode side and in the diffusion layer of the cathode 461c, and is perpendicular to the surface of the MEA 461 from the cathode offgas discharge port 422ho of the cathode facing plate 42. And is discharged from the cathode offgas discharge through hole 442Co of the anode facing plate 44 through the cathode offgas discharge flow path forming portion 432Cop and the cathode offgas discharge through hole 432Co of the intermediate plate 43.

  Here, in the fuel cell module 40, only the flow of air supplied to the cathode of the MEA 461 is shown, but the flow of hydrogen supplied to the anode 461a of the MEA 461 is the same.

C4. Effects of the comparative example and this example:
FIG. 6 is a perspective view showing a schematic configuration of a fuel cell stack 100A as a comparative example. The configuration of the fuel cell stack 100A is the same as the configuration of the fuel cell stack 100 of the above embodiment except for the air supply manifold and the position where the notch formed on the lower side surface of the fuel cell stack 100A is formed. is there. Hereinafter, regarding the fuel cell stack 100A, only portions different from the fuel cell stack 100 will be described, and description of the same portions will be omitted.

  As shown in the figure, in the fuel cell stack 100A, the four air supply ports 12Ai, 12Bi, 12Ci, 12Ci constituting the air supply manifold are formed along the lower long side inside the lower long side of the end plate 10a. Are formed adjacent to each other. These four air supply ports 12Ai, 12Bi, 12Ci, and 12Ci are arranged at positions facing each other with the air discharge ports formed inside the upper long side of the end plate 10a. Further, a notch portion 18a is formed between the air supply port 12Bi and the air supply port 12Ci, that is, at a position facing the notch portion 17a. Although illustration is omitted, in each member constituting the fuel cell module 40 in the fuel cell stack 100A, the air supply ports 12Ai, 12Bi, 12Ci, 12Ci and the through holes corresponding to the notches 18a are also provided. And a notch is formed.

  When the fuel cell stack 100A of the comparative example is compared with the fuel cell stack 100 of the above embodiment, the power generation efficiency of the fuel cell stack 100 of the above embodiment is higher than that of the fuel cell stack 100A of the comparative example. It has the effect of becoming higher. Hereinafter, this reason will be described.

  FIG. 7 is an explanatory diagram for explaining a difference in power generation efficiency between the fuel cell stack 100 </ b> A and the fuel cell stack 100. FIG. 7A shows a plan view of the seal gasket-integrated MEA 46A in the fuel cell stack 100A of the comparative example. FIG. 7B shows a plan view of the MEA 46 with an integrated seal gasket in the fuel cell stack 100 of the above embodiment.

  In the fuel cell stack 100A of the comparative example, as shown in FIG. 7A, the notch portion 467 and the notch portion 468 are disposed so as to face each other, and are disposed adjacent to each other with the notch therebetween. Two cathode offgas discharge manifolds (for example, the illustrated cathode offgas discharge through holes 462Bo and 462Co) and two air supply manifolds (for example, the illustrated air supply through holes 462Bi and 462Ci) face each other. Are arranged. For this reason, the distance between the two cathode off-gas exhaust manifolds described above and the distance between the two air supply manifolds are relatively long, and in the MEA 461, the air flows as indicated by broken line arrows in the figure, Air hardly flows in the region R between the notch 467 and the notch 468, and this region R is not effectively used for power generation.

  On the other hand, in the fuel cell stack 100 of the above embodiment, as shown in FIG. 7B, the notch 467 and the notches 468 and 469 are arranged at positions that do not face each other. Two air supply manifolds (for example, the illustrated air supply through holes 462Ai and 462Bi) disposed with the notch 468 interposed therebetween, and an air supply manifold (for example, illustrated) with the notch 469 interposed therebetween The air supply through holes 462Bi and 462Ci) are respectively disposed at positions facing at least a part of the four cathode off gas discharge manifolds (for example, the illustrated cathode off gas discharge through holes 462Ao, 462Bo, 462Co, and 462Do). Yes. Further, two cathode offgas discharge manifolds (for example, the illustrated cathode offgas discharge through holes 462Bo and 462Co) disposed with the notch 467 interposed therebetween are respectively provided with four air supply manifolds (for example, the illustrated air supply manifolds). The through holes 462Ai, 462Bi, 462Ci) are disposed at positions facing at least a part of the through holes. Therefore, in the MEA 461, air flows as indicated by the broken-line arrows in the drawing, and a region where the air hardly flows is less likely to occur. As a result, it is possible to generate power with substantially the entire MEA 461, increase the effective power generation area in the MEA 461, and improve the power generation efficiency.

D. Variation:
Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and can be implemented in various modes without departing from the scope of the present invention. For example, the following modifications are possible.

D1. Modification 1:
In the above embodiment, the number of notch portions (first fastening member installation portions) and fastening members (first fastening members) formed on the lower side surface of the fuel cell stack 100 is two, Although the number of notches (second fastening member installation portion) and fastening members (second fastening members) formed on the upper side surface is one, the present invention is not limited to this. The number of the first fastening member installation part, the first fastening member, the second fastening member installation part, and the second fastening member can be arbitrarily set.

  In the above embodiment, the number of air supply manifolds is three and the number of cathode offgas discharge manifolds is four. However, the present invention is not limited to this. The number of air supply manifolds and cathode offgas exhaust manifolds takes into account the number of first fastening member installation parts, the number of first fastening members, and the number of second fastening member installation parts and second fastening members, respectively. Any setting can be made.

D2. Modification 2:
In the above embodiment, the first fastening member installation part and the second fastening member installation part are provided with the first notch part and the second notch part. It is not limited to this. For example, each of the first fastening member installation part and the second fastening member installation part may be a through hole. In this case, for example, a bolt and a nut may be used as the fastening member.

D3. Modification 3:
In the said Example, arrangement | positioning of the 1st fastening member installation part in this invention, the 1st fastening member, the 2nd fastening member installation part, and the 2nd fastening member, and several reaction gas supply manifold Although the case where the arrangement of the plurality of off-gas discharge manifolds is applied to the air supply manifold and the cathode off-gas discharge manifold has been described, the present invention is not limited to this. The present invention may be applied to a hydrogen supply manifold and an anode offgas discharge manifold. Further, the present invention may be applied to both an air supply manifold, a cathode offgas discharge manifold, a hydrogen supply manifold, and an anode offgas discharge manifold.

D4. Modification 4:
In the said Example, although the 1st notch part and the 2nd notch part were formed also in end plate 10a, 10b, this invention is not limited to this. The end plates 10a and 10b may not be formed with the first fastening member installation part and the second fastening member installation part. In this case, similarly to the rod member 50, the fastening members 60, 70, and 80 may be fixed to the end plates 10a and 10b by bolts in the stacking direction of the stack structure.

D5. Modification 5:
In the above embodiment, the air supply ports 12Ai, 12Bi, and 12Ci and the cathode off-gas discharge ports 12Ao, 12Bo, 12Co, and 12Do are formed in the end plate 10a, but one of them is formed in the end plate 10b. It is good. The same applies to the hydrogen supply port 14i, the anode offgas discharge port 14o, the cooling water supply port 16i, and the cooling water discharge port 16o.

D6. Modification 6:
In the above embodiment, the members constituting the fuel cell stack 100 are each substantially rectangular, but the present invention is not limited to this. The present invention may be applied to a fuel cell stack in which polygonal laminated members having a first side surface and a second side surface facing each other are laminated.

D7. Modification 7:
In the above embodiment, the separator 41 configured by joining three flat plates of the cathode facing plate 42, the intermediate plate 43, and the anode facing plate 44 is used. However, the present invention is limited to this. Absent. For example, a separator having a flow path for flowing hydrogen, air, or cooling water may be used as a block-shaped member having conductivity.

1 is a perspective view showing a schematic configuration of a fuel cell stack 100 as one embodiment of the present invention. It is explanatory drawing which shows schematic structure of seal gasket integrated type MEA46. 3 is a plan view of components of a separator 41. FIG. 4 is a plan view of a separator 41. FIG. 3 is an explanatory diagram showing a cross-sectional structure of a fuel cell module 40. FIG. It is a perspective view which shows schematic structure of fuel cell stack 100A as a modification. 5 is an explanatory diagram for explaining a difference in power generation efficiency between the fuel cell stack 100A and the fuel cell stack 100. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,100A ... Fuel cell stack 10a, 10b ... End plate 12Ai, 12Bi, 12Ci, 12Di ... Air supply port 12Ao, 12Bo, 12Co, 12Do ... Cathode off-gas discharge port 14i ... Hydrogen supply port 14o ... Anode off-gas discharge port 16i ... Cooling Water supply port 16o ... Cooling water discharge port 17a, 18a, 19a ... Notch 20a, 20b ... Insulating plate 30a, 30b ... Current collector plate 32a, 32b ... Output terminal 40 ... Fuel cell module 41 ... Separator 42 ... Cathode facing plate 42c ... Notch portion 422Ai, 422Bi, 422Ci ... Air supply through-hole 422Ao, 422Bo, 422Co ... Cathode off-gas discharge through-hole 422hi ... Air supply port 422ho ... Cathode off-gas discharge port 424i ... Hydrogen supply through-hole 42 o ... Anode off gas discharge through hole 426i ... Cooling water supply through hole 426o ... Cooling water discharge through hole 427, 428, 429 ... Notch 43 ... Intermediate plate 43c ... Notch 432Ai, 432Bi, 432Ci ... Air supply Through-hole 432Aip, 432Bip, 432Cip ... Air supply flow path forming part 432Ao, 432Bo, 432Co, 432Do ... Cathode off-gas discharge through-hole 432Aop, 432Bop, 432Cop, 432Dop ... Cathode off-gas discharge flow path forming part 434i ... Hydrogen supply Through hole 434ip ... Hydraulic supply flow path forming part 434o ... Anode off gas discharge through hole 434op ... Anode off gas discharge flow path forming part 435 ... Cooling water flow part 436i ... Cooling water supply through hole 436o ... Cooling water discharge Through hole 4 37, 438, 439 ... Notch 44 ... Anode facing plate 44c ... Notch 442Ai, 442Bi, 442Ci ... Air supply through-hole 442Ao, 442Bo, 442Co, 442Do ... Cathode off-gas discharge through-hole 444i ... Hydrogen supply through-hole Hole 444o ... Anode off gas discharge through hole 444hi ... Hydrogen supply port 444ho ... Anode off gas discharge port 446i ... Cooling water supply through hole 446o ... Cooling water discharge through hole 447,448,449 ... Notch 45 ... Cooling water flow path Forming member 46, 46A ... Seal gasket integrated MEA
460 ... Seal gasket 460c ... Notch 461 ... MEA
461m ... electrolyte membrane 461a ... anode 461c ... cathode 462Ai, 462Bi, 462Ci ... air supply through-hole 462Ao, 462Bo, 462Co, 462Do ... cathode off-gas discharge through-hole 464i ... hydrogen supply through-hole 464o ... anode off-gas discharge through-hole 466i ... Cooling water supply through-hole 466o ... Cooling water discharge through-hole 467, 468, 469 ... Notch 47 ... Metal porous body layer 50 ... Rod member 52 ... Bolt 60 ... Fastening member 62 ... Bolt 70, 80 ... Fastening Member SL ... Seal line

Claims (5)

A fuel cell stack comprising a laminate in which a plurality of membrane electrode assemblies are laminated with a separator interposed therebetween,
A reaction gas that is disposed adjacent to each other in a partial region of the outer peripheral portion of the membrane electrode assembly and is supplied from the outside of the fuel cell stack is branched and supplied to the plurality of membrane electrode assemblies. Multiple reaction gas supply manifolds;
A part of the outer peripheral portion of the membrane electrode assembly, and disposed adjacent to each other in a region facing the region where the plurality of reaction gas supply manifolds are disposed across the membrane electrode assembly, A plurality of off-gas discharge manifolds for collecting off-gas which is an unconsumed reaction gas in a plurality of membrane electrode assemblies and discharging the gas to the outside of the fuel cell stack;
A first fastening member that is disposed in at least a part of the plurality of reactant gas supply manifolds and fastens the plurality of membrane electrode assemblies and the plurality of separators in the stacking direction. A first fastening member installation section;
A second fastening member disposed in at least a part of the plurality of off-gas discharge manifolds for fastening the plurality of membrane electrode assemblies and the plurality of separators in the stacking direction; 2 fastening member installation parts,
The first fastening member installation portion is disposed at a position facing at least a part of the plurality of off-gas exhaust manifolds,
The fuel cell stack, wherein the second fastening member installation portion is disposed at a position facing at least a part of the plurality of reaction gas supply manifolds. The fuel cell stack according to claim 1, wherein
The first fastening member installation part and the second fastening member installation part are arranged at positions that do not face each other across the membrane electrode assembly,
Of the plurality of reaction gas supply manifolds, both of the two reaction gas supply manifolds arranged with the first fastening member installation portion interposed therebetween are configured to discharge any one of the plurality of off gas discharge manifolds. It is arranged at a position facing at least a part of the manifold,
Of the plurality of off-gas discharge manifolds, both of the two off-gas discharge manifolds arranged with the second fastening member installation portion interposed therebetween are any one of the plurality of reaction gas supply manifolds. A fuel cell stack disposed at a position facing at least a part of the manifold. The fuel cell stack according to claim 1 or 2,
The reaction gas supply manifold is an air supply manifold for branching and supplying air containing oxygen as the oxidant gas to the cathodes respectively provided in the plurality of membrane electrode assemblies,
The fuel cell stack, wherein the off gas discharge manifold is a cathode off gas discharge manifold that collects cathode off gas that is unconsumed off gas at the cathode and discharges the cathode off gas to the outside of the fuel cell stack. The fuel cell stack according to any one of claims 1 to 3,
At least one of the first fastening member installation part and the second fastening member installation part is a fuel cell stack, which is at least a notch part provided in the separator. The fuel cell stack according to any one of claims 1 to 4,
A fuel cell stack, wherein the reaction gas and a porous member through which the off gas flows are interposed between the separator and the membrane electrode assembly from the reaction gas supply manifold to the off gas discharge manifold.

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