JP4344584B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell having an electrolyte / electrode structure configured by sandwiching an electrolyte between a pair of electrodes, and alternately stacking the electrolyte / electrode structure and a separator.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane). This fuel cell has an electrolyte membrane / electrode structure (electrolyte / electrode structure) in which an anode side electrode and a cathode side electrode each made of an electrode catalyst and porous carbon are provided on both sides of a solid polymer electrolyte membrane, It is configured by being sandwiched by a separator (bipolar plate). Usually, a fuel cell stack in which a predetermined number of the fuel cells are stacked is used.

  In this type of fuel cell, a fuel gas (reactive gas) supplied to the anode electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) is hydrogen ionized on the electrode catalyst, It moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. The cathode side electrode is supplied with an oxidant gas (reaction gas), for example, a gas mainly containing oxygen or air (hereinafter also referred to as oxygen-containing gas). Hydrogen ions, electrons and oxygen react to produce water.

  In the above fuel cell, a fuel gas channel (reactive gas channel) for flowing a fuel gas opposite to the anode side electrode and an oxidant gas for flowing the cathode gas facing the cathode side electrode in the plane of the separator. The oxidant gas flow path (reaction gas flow path) is provided. Further, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator. The fuel gas flow channel, the oxidant gas flow channel, and the cooling medium flow channel generally include a plurality of flow channel grooves provided from a flow channel inlet communication hole penetrating in the stacking direction of the separator toward the flow channel outlet communication hole. In addition, the flow path groove is configured by a straight groove or a folded flow path groove.

  However, when a channel inlet communication hole or a channel outlet communication hole having a small opening is provided for a plurality of channel grooves, a fluid such as a fuel gas, an oxidant gas, or a cooling medium is supplied along the channel groove. In order to flow smoothly, a buffer part is required around the flow path inlet communication hole and the flow path outlet communication hole.

  Thus, for example, a gas passage plate for a fuel cell disclosed in Patent Document 1 is known. In Patent Document 1, as shown in FIG. 11, for example, a gas passage plate 1 on the oxidant gas side includes a groove member 2 made of carbon or metal. An oxidant gas inlet manifold 3 is provided on the upper side of the gas passage plate 1, while an oxidant gas outlet manifold 4 is formed on the lower side of the gas passage plate 1.

  The groove member 2 includes an inlet-side flow groove 5a communicating with the inlet manifold 3, an outlet-side flow groove 5b communicating with the outlet manifold 4, the inlet-side flow groove 5a, and the outlet-side flow groove 5b. And an intermediate flow groove 6 that communicates with each other. The inlet-side flow groove 5a and the outlet-side flow groove 5b are formed in a lattice shape via a plurality of projections 7a, while the intermediate flow groove 6 is formed in a bent shape that is folded back a plurality of times. The linear groove part 8 and the grid | lattice-like groove part 9 formed in the folding | returning site | part by the some protrusion 7b are provided.

  In the gas passage plate 1 of the fuel cell configured as described above, the inlet-side flow groove 5a and the outlet-side flow groove 5b constitute a buffer portion, and the contact area of the supply gas to the electrode is widened. While this supply gas can move freely, in the intermediate flow groove 6, the reaction gas can flow uniformly at a high speed through the plurality of linear grooves 8.

Japanese Patent Laid-Open No. 10-106594 (FIG. 1)

  In this case, the gas passage plate 1 is actually formed with a plurality of meandering channels (serpentine channels) 1 a extending from the inlet manifold 3 to the outlet manifold 4. At that time, in the plurality of linear grooves 8, the lengths of the respective channels 1a are substantially the same, and the respective channel resistances are likely to be constant.

  However, in the inlet-side flow grooves 5a and the outlet-side flow grooves 5b formed in a lattice shape through the plurality of protrusions 7a, the respective flow paths 1a from the inlet manifold 3 and the outlet manifold 4 to the respective linear grooves 8 are provided. Are different in length. As a result, the flow resistance in the inlet-side flow groove 5a and the outlet-side flow groove 5b fluctuates, and the reaction gas cannot be uniformly supplied over the entire electrode surface, resulting in a decrease in reaction gas distribution. Has been pointed out.

  On the other hand, in the lattice-shaped groove portion 9 formed by the plurality of protrusions 7b, the reaction gas introduced into each linear groove portion 8 after being led out from each linear groove portion 8 to the lattice-shaped groove portion 9 and turned back, Since the lengths of the respective flow paths 1a are different, uniform distribution cannot be maintained. For this reason, it becomes difficult to uniformly supply the reaction gas over the entire electrode surface, and there is a problem that desired power generation performance cannot be ensured.

  The present invention solves this kind of problem, can equalize the flow resistance in the meandering reactive gas flow path, distributes the reactive gas well over the entire electrode surface, and has good power generation performance An object of the present invention is to provide a fuel cell capable of ensuring the above.

In the fuel cell of the present invention, the reaction gas flow channel for supplying the reaction gas along the surface direction of the electrode includes a plurality of serpentine flow channel grooves having substantially the same length and having even-numbered turn-back portions in the separator surface. ing. The reaction gas flow path includes a reaction gas inlet communication hole penetrating in the stacking direction, a substantially triangular inlet buffer portion communicating with the serpentine flow channel groove, and a reaction gas outlet communication hole penetrating in the stacking direction. A substantially triangular outlet buffer portion communicating with the flow channel is provided, and the inlet buffer portion and the outlet buffer portion are configured to be substantially symmetrical with each other. Furthermore, one side of the inlet buffer portion is substantially orthogonal to one end portion of the serpentine flow channel, and one side of the outlet buffer portion is substantially orthogonal to the other end portion of the serpentine flow channel. Yes. The reaction gas inlet communication hole is disposed in the extending direction of one end of the serpentine flow channel, and the reaction gas outlet communication hole is extended in the other end of the serpentine flow channel. Is arranged.

  In addition, it is preferable that at least one of the inlet buffer portion and the outlet buffer portion is provided with a plurality of embossments.

  Further, the reaction gas inlet communication hole and the reaction gas outlet communication hole are provided with a hypotenuse on at least one side, and the hypotenuse of the reaction gas inlet communication hole faces the inclined portion of the inlet buffer portion, while the reaction gas outlet It is preferable that the oblique side of the communication hole is opposed to the inclined portion of the outlet buffer portion.

  In the fuel cell according to the present invention, since each serpentine channel groove constituting the reaction gas channel has substantially the same channel length, the channel resistance is made uniform, so that each serpentine flow The reaction gas can be uniformly supplied to the road groove. Further, the apparatus includes a substantially triangular inlet buffer portion and a substantially triangular outlet buffer portion that constitute the reaction gas flow path, and the inlet buffer portion and the outlet buffer portion are configured to be substantially symmetrical with each other. .

  Accordingly, the flow resistance of the entire reaction gas flow path from the reaction gas inlet communication hole to the reaction gas outlet communication hole is made uniform, and the distribution of the reaction gas in the reaction gas flow path is further improved. As a result, the power generation performance of the fuel cell can be effectively maintained.

  FIG. 1 is an exploded perspective view of a main part of a fuel cell 10 according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional explanatory view of the fuel cell 10.

  The fuel cell 10 is configured by alternately laminating electrolyte membrane / electrode structures (electrolyte / electrode structures) 12 and separators 13, and the separators 13 are first and second metal plates that are laminated to each other. 14 and 16 are provided.

  As shown in FIG. 1, an oxidant gas (reactive gas), for example, an oxygen-containing gas is supplied to one end edge of the fuel cell 10 in the arrow B direction so as to communicate with each other in the direction of arrow A, which is the stacking direction. An oxidant gas inlet communication hole (reactive gas inlet communication hole) 20a for supplying a coolant, a cooling medium inlet communication hole 22a for supplying a cooling medium, and a fuel gas (reactive gas), for example, a fuel for discharging a hydrogen-containing gas Gas outlet communication holes (reactive gas outlet communication holes) 24b are arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, discharges a fuel gas inlet communication hole (reactive gas inlet communication hole) 24a for supplying fuel gas, and discharges the cooling medium. A cooling medium outlet communication hole 22b for the purpose and an oxidant gas outlet communication hole (reaction gas outlet communication hole) 20b for discharging the oxidant gas are arranged in the direction of arrow C.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 26 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 28 and a cathode side electrode that sandwich the solid polymer electrolyte membrane 26. 30.

  The anode side electrode 28 and the cathode side electrode 30 include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. Respectively. The electrode catalyst layers are bonded to both surfaces of the solid polymer electrolyte membrane 26 so as to face each other with the solid polymer electrolyte membrane 26 interposed therebetween.

  As shown in FIGS. 1 and 3, an oxidant gas flow path (reaction gas flow path) 32 is provided on the surface 14a of the first metal plate 14 on the electrolyte membrane / electrode structure 12 side. The gas flow path 32 communicates with the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b. The oxidant gas passage 32 is provided in the vicinity of the substantially right triangle (substantially triangular) inlet buffer 34 provided in the vicinity of the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b. And an outlet buffer portion 36 having a substantially right triangle shape (substantially triangular shape). The inlet buffer portion 34 and the outlet buffer portion 36 are configured to be substantially symmetrical with each other, and are provided with a plurality of embosses 34a and 36a.

  The inlet buffer unit 34 and the outlet buffer unit 36 communicate with each other through three oxidant gas flow channel grooves 38a, 38b, and 38c. The oxidant gas channel grooves 38a to 38c extend in the direction of arrow C while meandering in the direction of arrow B in parallel with each other. Specifically, as the oxidant gas flow channel grooves 38a to 38c, a serpentine flow channel groove having one and a half reciprocations in the direction of the arrow B having an even number of times, for example, two turn-back portions T1 and T2. Thus, the lengths of the respective channels are set to substantially the same length.

  As shown in FIG. 3, the vertical portion (one side) 34 b of the inlet buffer portion 34 is arranged in the direction of the arrow C and is substantially orthogonal to the terminal portions of the oxidant gas flow channel grooves 38 a to 38 c. The inclined portion 34c of the buffer portion 34 is disposed toward the oxidant gas inlet communication hole 20a. Various shapes such as a quadrangle, a parallelogram, and a trapezoid are selected for the oxidant gas inlet communication hole 20a, and the inner wall surface forming the oxidant gas inlet communication hole 20a is connected to the inlet buffer 34. A hypotenuse 37a that is opposite and parallel to the inclined portion 34c is provided.

  The shape of the oxidant gas inlet communication hole 20a is variously selected as described above, and overhang portions 39a and 39b that bulge toward the oxidant gas inlet communication hole 20a may be provided. Hereinafter, the oxidant gas outlet communication hole 20b, the fuel gas inlet communication hole 24a, and the fuel gas outlet communication hole 24b are also configured similarly to the oxidant gas inlet communication hole 20a.

  A vertical portion (one side) 36b of the outlet buffer portion 36 is disposed in the direction of arrow C, is substantially orthogonal to the terminal portions of the oxidant gas flow channel grooves 38a to 38c, and is also oxidant gas flow channel grooves 38a to 38a. 38c is regulated to approximately the same length between the vertical portions 34b and 36b. The inclined portion 36c of the outlet buffer portion 36 is disposed to face the oxidizing gas outlet communication hole 20b. A hypotenuse 37b parallel to the inclined portion 36c is provided on the inner wall surface forming the oxidant gas outlet communication hole 20b.

  The surface 14a of the first metal plate 14 is provided with a linear seal 40 that covers the oxidant gas inlet communication hole 20a, the oxidant gas outlet communication hole 20b, and the oxidant gas flow path 32 and seals the oxidant gas. .

  A cooling medium flow path 42 is integrally formed on the surfaces 14b and 16a of the first metal plate 14 and the second metal plate 16 facing each other. As shown in FIG. 4, the cooling medium flow path 42 is provided in the vicinity of both ends in the direction of arrow C of the cooling medium inlet communication hole 22a, for example, substantially triangular first and second inlet buffer portions 44 and 46, and The cooling medium outlet communication holes 22b are provided in the vicinity of both ends in the direction of arrow C, for example, with first and second outlet buffer parts 48 and 50 having a substantially triangular shape.

  The first inlet buffer unit 44 and the second outlet buffer unit 50 are configured to be substantially symmetrical with each other, and the second inlet buffer unit 46 and the first outlet buffer unit 48 are substantially symmetrical to each other. Configured. The first inlet buffer unit 44, the second inlet buffer unit 46, the first outlet buffer unit 48, and the second outlet buffer unit 50 are configured by a plurality of embosses 44a, 46a, 48a, and 50a.

  The cooling medium inlet communication hole 22a and the first and second inlet buffer portions 44 and 46 communicate with each other via the first and second inlet communication channels 52 and 54, while the cooling medium outlet communication hole 22b and the first communication hole 22b. The first and second outlet buffer portions 48 and 50 communicate with each other via first and second outlet communication channels 56 and 58. The first inlet communication channel 52 includes, for example, two channel grooves, and the second inlet communication channel 54 includes, for example, six channel grooves. Similarly, the first outlet communication channel 56 is provided with six channel grooves, while the second outlet communication channel 58 is provided with two channel grooves.

  The number of flow paths of the first inlet communication flow path 52 and the number of flow paths of the second inlet communication flow path 54 are not limited to 2 and 6, and the number of the respective flow paths is The same may be set. The same applies to the first and second outlet communication channels 56 and 58.

  The first inlet buffer unit 44 and the first outlet buffer unit 48 communicate with each other via linear flow channel grooves 60, 62, 64 and 66 extending in the direction of arrow B, and the second inlet buffer unit. 46 and the second outlet buffer section 50 communicate with each other through linear flow channel grooves 68, 70, 72 and 74 extending in the direction of arrow B. Between the linear flow channel grooves 66 and 68, linear flow channel grooves 76 and 78 are provided so as to extend a predetermined length in the arrow B direction.

  The linear flow channel grooves 60 to 74 communicate with each other via linear flow channel grooves 80 and 82 extending in the direction of arrow C. The straight flow channel grooves 62 to 78 communicate with each other via the straight flow channel grooves 84 and 86 extending in the direction of the arrow C, and the straight flow channel grooves 64, 66 and 76 and the straight flow channel grooves 68, 70 and 78 communicate with each other via linear flow channel grooves 88 and 90 extending intermittently in the direction of arrow C.

  The cooling medium flow path 42 is distributed between the first metal plate 14 and the second metal plate 16, and the cooling medium flow path 42 is formed by overlapping the first and second metal plates 14, 16 with each other. It is formed. As shown in FIG. 5, a part of the cooling medium flow path 42 is formed on the surface 14b of the first metal plate 14 so as to avoid the oxidant gas flow path 32 formed on the surface 14a side.

  In addition, although the oxidant gas flow path 32 formed on the surface 14a protrudes in a convex shape on the surface 14b, the convex portion is not shown for easy understanding of the cooling medium flow channel 42. . Similarly, in the surface 16a shown in FIG. 6, illustration of a portion in which a later-described fuel gas channel (reactive gas channel) 96 formed on the surface 16b protrudes convexly on the surface 16a is omitted.

  The surface 14b has a first inlet buffer portion 44 communicating with the cooling medium inlet communication hole 22a via two first inlet communication channels 52, and two second holes connected to the cooling medium outlet communication hole 22b. A second outlet buffer unit 50 communicating with the outlet communication channel 58 is provided.

  In the first inlet buffer portion 44, the groove portions 60a, 62a, 64a and 66a are intermittently provided along the arrow B direction so as to avoid the folded portion T2 and the outlet buffer portion 36 of the oxidant gas flow channel grooves 38a to 38c. And a predetermined length. In the second outlet buffer unit 50, grooves 68a, 70a, 72a and 74a are predetermined along the direction of arrow B so as to avoid the folded portion T1 of the oxidant gas flow channel grooves 38a to 38c and the inlet buffer unit 34. It is provided in the position.

  The groove portions 60a to 78a constitute part of the linear flow channel grooves 60 to 78, respectively. The groove portions 80a to 90a constituting the straight flow path grooves 80 to 90 are provided over a predetermined length in the direction of arrow C so as to avoid meandering oxidant gas flow path grooves 38a to 38c.

  As shown in FIG. 6, a part of the cooling medium flow path 42 is formed on the surface 16a of the second metal plate 16 so as to avoid a fuel gas flow path 96 described later. Specifically, a second inlet buffer portion 46 that communicates with the cooling medium inlet communication hole 22a and a first outlet buffer portion 48 that communicates with the cooling medium outlet communication hole 22b are provided.

  While the groove portions 68b to 74b constituting the straight flow path grooves 68 to 74 are intermittently communicated with the second inlet buffer portion 46 in a predetermined length along the arrow B direction, Grooves 60b to 66b constituting the straight flow path grooves 60 to 66 are set in a predetermined shape and communicated with the part 48. On the surface 16a, groove portions 80b to 90b constituting the straight flow path grooves 80 to 90 are provided extending in the direction of the arrow C.

  In the cooling medium flow path 42, a part of the straight flow path grooves 60 to 78 extending in the direction of the arrow B has different flow path cross-sectional areas because the respective groove portions 60 a to 78 a and 60 b to 78 b face each other. The main flow path is configured by enlarging twice as much as this part (see FIG. 4). The straight channel grooves 80 to 90 are partly polymerized and distributed to the first and second metal plates 14 and 16, respectively. Between the surface 14a of the first metal plate 14 and the surface 16a of the second metal plate 16, a linear seal 40a surrounding the cooling medium flow path 42 is interposed.

  As shown in FIG. 7, a fuel gas channel 96 is provided on the surface 16 b of the second metal plate 16 on the electrolyte membrane / electrode structure 12 side. The fuel gas channel 96 has a substantially right triangle (substantially triangular) inlet buffer portion 98 provided in the vicinity of the fuel gas inlet communication hole 24a, and a substantially right triangle in the vicinity of the fuel gas outlet communication hole 24b. And an outlet buffer section 100 having a shape (substantially triangular).

  The inlet buffer unit 98 and the outlet buffer unit 100 are configured to be substantially symmetrical with each other, and are provided with a plurality of embosses 98a and 100a, for example, via three fuel gas flow channel grooves 102a, 102b and 102c. Communicate. The fuel gas flow channel grooves 102a to 102c extend in the direction of the arrow C while meandering in the direction of the arrow B, and are provided with an even number of times, for example, two turn-back portions T3 and T4, so By constituting the serpentine channel groove, each channel length is set to substantially the same length.

  The vertical portion (one side) 98b of the inlet buffer portion 98 is disposed in the direction of arrow C, is substantially orthogonal to the end portions of the fuel gas flow channel grooves 102a to 102c, and the inclined portion 98c is formed in the fuel gas inlet communication hole 24a. It is arranged toward. On the inner wall surface constituting the fuel gas inlet communication hole 24a, a hypotenuse 104a is formed facing the inclined portion 98c and parallel to the inclined portion 98c. The vertical portion (one side) 100b of the outlet buffer portion 100 is disposed in the direction of arrow C, is substantially orthogonal to the end portions of the fuel gas flow channel grooves 102a to 102c, and the inclined portion 100c is formed in the fuel gas outlet communication hole 24b. Opposed to each other. A hypotenuse 104b parallel to the inclined portion 100c is formed on the inner wall surface constituting the fuel gas outlet communication hole 24b. A linear seal 40b surrounding the fuel gas flow path 96 is provided on the surface 16b.

  The operation of the fuel cell 10 according to this embodiment configured as described above will be described below.

  As shown in FIG. 1, a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a, and an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 20a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 22a.

  The oxidant gas is introduced into the oxidant gas channel 32 of the first metal plate 14 from the oxidant gas inlet communication hole 20a. In the oxidant gas flow path 32, as shown in FIG. 3, the oxidant gas is once introduced into the inlet buffer 34 and then dispersed in the oxidant gas flow path grooves 38a to 38c. For this reason, the oxidant gas moves along the cathode side electrode 30 of the electrolyte membrane / electrode structure 12 while meandering through the oxidant gas flow channel grooves 38a to 38c.

  On the other hand, the fuel gas is introduced into the fuel gas channel 96 of the second metal plate 16 from the fuel gas inlet communication hole 24a. In the fuel gas channel 96, as shown in FIG. 7, the fuel gas is once introduced into the inlet buffer portion 98 and then dispersed in the fuel gas channel grooves 102a to 102c. Further, the fuel gas meanders through the fuel gas flow channel grooves 102 a to 102 c and moves along the anode side electrode 28 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 30 and the fuel gas supplied to the anode side electrode 28 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the consumed fuel gas supplied to the anode side electrode 28 is discharged from the outlet buffer unit 100 to the fuel gas outlet communication hole 24b. Similarly, the oxidant gas consumed by being supplied to the cathode side electrode 30 is discharged from the outlet buffer 36 to the oxidant gas outlet communication hole 20b.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 22 a is introduced into a cooling medium flow path 42 formed between the first and second metal plates 14 and 16. In the cooling medium flow path 42, as shown in FIG. 4, the first and second inlets 52 and 54 extend from the cooling medium inlet communication hole 22a in the direction of the arrow C. The cooling medium is once introduced into the inlet buffer sections 44 and 46.

  The cooling medium introduced into the first and second inlet buffer sections 44 and 46 is dispersed in the linear flow channel grooves 60 to 66 and 68 to 74 and moves in the horizontal direction (arrow B direction). Are supplied to the straight flow channel grooves 80 to 90 and 76, 78. Therefore, after the cooling medium is supplied over the entire power generation surface of the electrolyte membrane / electrode structure 12, it is once introduced into the first and second outlet buffer portions 48 and 50, and further, the first and second outlet communication flows. It is discharged to the cooling medium outlet communication hole 22b through the paths 56 and 58.

  In this case, in this embodiment, as shown in FIG. 7, the fuel gas flow path 96 includes three fuel gas flow path grooves 102 a to 102 c having two turn-back portions T3 and T4 in the surface 16 b. The fuel gas channel grooves 102a to 102c are set to have substantially the same channel length. Therefore, the flow resistance of the fuel gas in the fuel gas flow channel grooves 102a to 102c is made uniform, and the fuel gas can be supplied uniformly along the fuel gas flow channel grooves 102a to 102c.

  Furthermore, the fuel gas channel 96 includes a substantially triangular inlet buffer portion 98 and an outlet buffer portion 100, respectively, and the inlet buffer portion 98 and the outlet buffer portion 100 are configured to be substantially symmetrical with each other. Yes. Therefore, as shown in FIG. 8, the sum of the flow path resistance of the inlet buffer unit 98 and the flow path resistance of the outlet buffer unit 100 becomes substantially the same value on both sides of the fuel gas flow channel grooves 102a to 102c. Yes.

  Thereby, the flow resistance of the entire fuel gas flow path 96 from the fuel gas inlet communication hole 24a to the fuel gas outlet communication hole 24b is made uniform, and the fuel gas distribution property in the fuel gas flow path 96 is further improved. To do. For this reason, the effect that fuel gas can be supplied uniformly and reliably over the whole electrode surface of the anode side electrode 28 is acquired.

  Moreover, the inlet buffer section 98 and the outlet buffer section 100 are provided with a plurality of embossments 98a and 100a. Accordingly, the fuel gas can be distributed uniformly, and the strength of the fuel gas can be improved and the adjacent electrolyte membrane / electrode structure 12 can be reliably supported.

  Further, since the inlet buffer unit 98 and the outlet buffer unit 100 are configured in a substantially triangular shape, the area can be reduced as compared with a conventional rectangular buffer unit. Thereby, the exclusive area of the inlet buffer unit 98 and the outlet buffer unit 100 is effectively narrowed, and the effect that the separator 13 itself can be easily reduced in size is obtained.

  Furthermore, the inclined portions 98c and 100c of the inlet buffer portion 98 and the outlet buffer portion 100 face the oblique sides 104a and 104b of the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b and are parallel to the inclined portions 98c and 100c. is doing. Accordingly, it is possible to satisfactorily ensure the cross-sectional areas of the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b with a compact configuration.

  Further, the vertical portions 98b and 100b of the inlet buffer portion 98 and the outlet buffer portion 100 are substantially orthogonal to the end portions of the fuel gas flow channel grooves 102a to 102c. Therefore, the fuel gas can flow smoothly from the inlet buffer portion 98 to the fuel gas flow channel grooves 102a to 102c, and the fuel gas can flow smoothly from the fuel gas flow channel grooves 102a to 102c to the outlet buffer portion 100. It becomes possible.

  On the other hand, as shown in FIG. 3, in the oxidant gas flow channel 32, like the fuel gas flow channel 96, the three oxidant gas flow channel grooves 38 a to 38 c have a serpentine flow having substantially the same length. It constitutes a road groove. Furthermore, the inlet buffer part 34 and the outlet buffer part 36 provided at both ends of the oxidant gas flow path grooves 38a to 38c are substantially triangular and substantially symmetrical with each other.

  Accordingly, the flow resistance of the entire oxidant gas flow path 32 extending from the oxidant gas inlet communication hole 20a to the oxidant gas outlet communication hole 20b is surely made uniform, and the oxidant gas distribution in the oxidant gas flow path 32 is ensured. The efficiency is effectively improved. For this reason, it becomes possible to supply oxidant gas uniformly and reliably over the whole electrode surface of the cathode side electrode 30. Thereby, the advantage that the power generation performance of the fuel cell 10 can be effectively maintained is obtained.

  The oxidant gas flow channel grooves 38a to 38c and the fuel gas flow channel grooves 102a to 102c constitute one reciprocal half serpentine flow channel having two folded portions, but are not limited thereto. Instead, it is only necessary to have an even number of folding sites, such as 4 times or 6 times.

  Further, in the present embodiment, for example, the inlet buffer unit 34 has been described as the substantially triangular buffer unit, but the present invention is not limited to this. The inlet buffer unit 120 shown in FIG. 9 is configured in a substantially triangular shape (including a substantially trapezoidal shape) having a bottom side 120a and a top side 120b. On the other hand, the inlet buffer portion 130 shown in FIG. 10 is configured in a substantially triangular shape having an inclined bottom portion 130a.

It is a principal part disassembled perspective view of the fuel cell which concerns on embodiment of this invention. It is a partial cross section explanatory view of the fuel cell. It is front explanatory drawing of one surface of a 1st metal plate. It is a perspective explanatory view of a cooling medium channel formed in a separator. It is front explanatory drawing of the other surface of the said 1st metal plate. It is front explanatory drawing of a 2nd metal plate. It is front explanatory drawing of the other surface of the said 2nd metal plate. FIG. 6 is a relationship diagram between the position of the fuel gas flow path and the flow path resistance. It is explanatory drawing of the entrance buffer part which has another shape. It is explanatory drawing of the entrance buffer part which has another shape. 6 is an explanatory view of a gas passage plate of a fuel cell of Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Electrolyte membrane and electrode structure 13 ... Separator 14, 16 ... Metal plate 20a ... Oxidant gas inlet communication hole 20b ... Oxidant gas outlet communication hole 22a ... Cooling medium inlet communication hole 22b ... Cooling medium outlet communication Hole 24a ... Fuel gas inlet communication hole 24b ... Fuel gas outlet communication hole 26 ... Solid polymer electrolyte membrane 28 ... Anode side electrode 30 ... Cathode side electrode 32 ... Oxidant gas flow path 34, 44, 46, 98, 120, 130 ... Inlet buffer parts 36, 48, 50, 100 ... Outlet buffer parts 38a to 38c ... Oxidant gas flow path groove 42 ... Cooling medium flow path 96 ... Fuel gas flow path 102a-102c ... Fuel gas flow path groove

Claims (3)

It has an electrolyte / electrode structure constructed by sandwiching an electrolyte between a pair of electrodes, and alternately stacks the electrolyte / electrode structure and separator, and penetrates in the stacking direction to react gas inlet communication holes and reactions. A fuel cell in which a gas outlet communication hole is formed,
A reaction gas flow path for supplying a reaction gas along the surface direction of the electrode;
The reaction gas flow path includes a plurality of serpentine flow path grooves having substantially the same length and having an even number of turn-back portions in the separator surface,
A substantially triangular inlet buffer portion communicating the serpentine flow channel with the reactive gas inlet communication hole;
A substantially triangular outlet buffer portion communicating the serpentine flow channel with the reactive gas outlet communication hole;
With
The inlet buffer portion and the outlet buffer portion are configured in a substantially symmetrical shape with respect to each other .
One side of the inlet buffer portion is substantially orthogonal to one end portion of the serpentine channel groove,
One side of the outlet buffer portion is substantially orthogonal to the other end portion of the serpentine channel groove,
The reaction gas inlet communication hole is disposed in the extending direction of one end of one end of the serpentine flow channel,
The fuel cell according to claim 1, wherein the reaction gas outlet communication hole is arranged in an extending direction of the other end portion of the other serpentine channel groove .   2. The fuel cell according to claim 1, wherein at least one of the inlet buffer portion and the outlet buffer portion is provided with a plurality of embosses. The fuel cell according to claim 1 or 2, wherein the reactive gas inlet communication hole and the reactive gas outlet communication hole are provided with a hypotenuse on at least one side,
The oblique side of the reaction gas inlet communication hole faces the inclined portion of the inlet buffer portion, while the oblique side of the reaction gas outlet communication hole faces the inclined portion of the outlet buffer portion. battery.

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