JP4803957B2 - Internal manifold fuel cell - Google Patents

Description

  The present invention includes a power generation cell in which an electrolyte membrane / electrode structure in which an electrolyte membrane is disposed between a pair of electrodes and a metal separator are stacked, and the power generation cell penetrates in the stacking direction to the reaction gas flow path. The present invention relates to an internal manifold type fuel cell in which a reaction gas communication hole and a cooling medium communication hole communicating with a cooling medium flow path are provided.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are respectively provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane) is used as a separator. A power generation cell sandwiched between the two. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of power generation cells.

  In this power generation cell, the fuel gas supplied to the anode side electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is ionized with hydrogen on the electrode catalyst, and the cathode passes through the electrolyte membrane. Move to the side electrode side. 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, for example, a gas mainly containing oxygen or air (hereinafter also referred to as an oxygen-containing gas). And oxygen reacts to produce water.

  In the power generation cell, a reaction gas channel for flowing a reaction gas is provided in the plane of the separator so as to face each electrode, and the power generation cell is cooled between separators constituting adjacent power generation cells. A cooling medium flow path for flowing the cooling medium is provided. The reactive gas is an oxidant gas and a fuel gas, and the reactive gas flow path is an oxidant gas flow path for flowing the oxidant gas facing the cathode side electrode, and a fuel gas facing the anode side electrode. And a fuel gas flow path for flowing gas.

  By the way, this type of separator is usually formed of a carbon member or the like, and it has been pointed out that the processing cost increases and the size cannot be reduced. For this reason, the metal separator which gave the uneven | corrugated press processing to the thin metal plate is employ | adopted.

  In that case, the unevenness | corrugation for forming a reaction gas flow path and a cooling medium flow path is integrally provided in both surfaces of the metal separator. Therefore, for example, if a serpentine-shaped reaction gas flow path is provided on one surface of the metal separator, the other surface is constrained by the shape of the reaction gas flow path, and a cooling medium flow path having a desired shape is formed. There is a possibility that it cannot be provided. In particular, in the internal manifold fuel cell in which the reaction gas communication hole and the cooling medium communication hole are formed in the peripheral portion of the metal separator in the stacking direction of the metal separator, the cooling medium communication hole, the cooling medium flow path, There is a problem that it is not possible to communicate well.

  Therefore, for example, a fuel cell separator disclosed in Patent Document 1 is employed. This separator is composed of two metal plates that are formed with irregularities to form gas passages on the outer surface, and an intermediate metal that is sandwiched between the two metal plates and has an irregularity to form cooling water channels on the front and back sides. And a board.

Japanese Patent Laying-Open No. 2002-75395 (FIG. 3)

  In the above-mentioned patent document 1, the separator sandwiches one intermediate metal plate between two metal plates, and includes three metal plates as a whole. For this reason, the number of metal plates is large, and particularly when several tens to several hundreds of power generation cells are stacked, the number of the metal plates increases considerably. As a result, the separator mounting operation becomes complicated and time consuming, and the cost increases. Moreover, each separator is provided with three metal plates in the stacking direction, so that the dimension in the stacking direction increases, and the entire fuel cell becomes large in the stacking direction.

  The present invention solves this type of problem, and has an economical and compact configuration, is not affected by the shape of the reaction gas flow path, and allows the cooling medium to flow well and uniformly between the power generation cells. An object is to provide a possible internal manifold fuel cell.

  In an internal manifold fuel cell according to the present invention, a power generation cell having an electrolyte membrane / electrode structure in which an electrolyte membrane is disposed between a pair of electrodes and a pair of plate-like metal separators sandwiching the electrolyte membrane / electrode structure And a reaction gas flow path for supplying a reaction gas along the electrode surface is formed between the electrolyte membrane / electrode structure and the metal separator. Further, a cooling medium flow path for supplying a cooling medium is formed between the power generation cells stacked in the horizontal direction, and the power generation cell has a reaction gas communication hole penetrating in the stacking direction and communicating with the reaction gas flow path. And a cooling medium communication hole communicating with the cooling medium flow path is provided.

  The reactive gas flow path is configured in a meandering flow path shape having a folded portion, and at least the folded portion that is folded close to the cooling medium communication hole is configured by a plurality of protrusions.

  Further, the power generation cell includes a fuel gas communication hole and an oxidant gas communication hole, which are reaction gas communication holes, and the fuel gas communication hole and the oxidation gas, on the first and second sides facing each other in the horizontal direction. A cooling medium communication hole is formed between the agent gas communication holes, and the cooling medium flow path is a linear flow path that connects the cooling medium communication holes on the first and second sides. It is preferable to provide.

  Further, the fuel gas communication hole and the oxidant gas communication hole are preferably arranged such that the gas inlet side communication hole is disposed above the gas outlet side communication hole.

  According to the present invention, since the plurality of projections are provided at least at the folded portion of the reaction gas channel close to the cooling medium communication hole, the surface of the metal separator has a channel (corresponding to the gap between the projections). Buffer portion) is formed. Therefore, even if a reaction gas flow path configured in a meandering flow path shape is provided on one surface of the metal separator, the other surface of the metal separator is constrained by the shape of the reaction gas flow path. Instead, the cooling medium can be supplied directly to the cooling medium flow path from the cooling medium communication hole.

  Specifically, when the reaction gas flow path is configured by a groove part and a peak part (convex concave part), the groove part and the peak part are located between the cooling medium communication hole and the cooling medium flow path at the folded portion. It will be formed crossing the medium flow path. As a result, the cooling medium cannot be supplied from the cooling medium communication hole to the cooling medium flow path, and measures such as changing the position of the cooling medium communication hole are required.

  On the other hand, by providing a flow path composed of a plurality of protrusions corresponding to the folded portion, the degree of freedom in the arrangement of the cooling medium communication holes and the layout is ensured. Moreover, since the cooling medium is once supplied to the flow path which is the buffer unit, it is uniformly distributed to the cooling medium flow path. Therefore, it is possible to effectively prevent the occurrence of reaction distribution due to the non-uniform flow of the cooling medium, local condensation in the reaction gas flow path, or a decrease in durability of the electrolyte membrane / electrode structure due to heat generation. .

  In addition, since the fuel gas communication hole, the cooling medium communication hole, and the oxidant gas communication hole are formed in the first and second sides facing each other in the horizontal direction, the height dimension of the metal separator (the first dimension) 3) and the fourth side) can be shortened satisfactorily. As a result, the height dimension of the entire fuel cell can be effectively suppressed, and the configuration is suitable for in-vehicle use, particularly for mounting under the floor. Furthermore, since the cooling medium flow path is provided with a linear flow path that connects the cooling medium communication holes, the inside of the electrode surface can be uniformly cooled, and local condensation or heat generation can be prevented.

  Furthermore, since the gas inlet-side communication hole is disposed above the gas outlet-side communication hole, the generated water droplets existing in the reaction gas channel are well discharged to the gas outlet-side communication hole by gravity. The

  FIG. 1 is an exploded perspective view of a main part of a power generation cell 10 constituting an internal manifold fuel cell according to an embodiment of the present invention, and FIG. 2 shows a plurality of the power generation cells 10 in a horizontal direction (arrow A direction). 1 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along the line III-III in FIG. .

  As shown in FIG. 1, in the power generation cell 10, the electrolyte membrane / electrode structure 14 is sandwiched between first and second metal separators 16 and 18. The first and second metal separators 16 and 18 are press-molded with a plate-shaped metal plate, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or the like.

  One end edge (first side) of the power generation cell 10 in the arrow B direction (horizontal direction in FIG. 1) communicates with each other in the arrow A direction, which is the stacking direction, and an oxidant gas, for example, an oxygen-containing gas Oxidant gas inlet communication hole (gas inlet side communication hole) 20a for supplying gas, cooling medium outlet communication hole 22b for discharging the cooling medium, and fuel gas for discharging a hydrogen gas, for example, a hydrogen-containing gas Outlet communication holes (gas outlet side communication holes) 24b are arranged in the direction of arrow C (vertical direction).

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

  As shown in FIGS. 1 and 4, for example, an oxidant gas which is a meandering flow path that folds back and forth in the direction of arrow B by one reciprocal half in the direction 16 a facing the electrolyte membrane / electrode structure 14 of the first metal separator 16. A flow path (reactive gas flow path) 26 is provided. The oxidant gas flow path 26 includes a plurality of grooves 28 provided by forming the first metal separator 16 into a wave shape. The groove portion 28 extends substantially linearly in the direction of arrow B.

  The first metal separator 16 is provided with a plurality of projections 30 protruding on the surface 16a side on both sides of the plurality of groove portions 28 in the direction of arrow B, and the folding partition members 32a and 32b are in the direction of arrow C with respect to each other. They are spaced apart and arranged in a staggered manner. The partition members 32a and 32b are made of, for example, a seal member and are integrated with the surface 16a, and folded portions 34a and 34b are provided on the short side, respectively. In addition, you may provide the partition members 32a and 32b integrally by press molding, for example.

  The folded portions 34a and 34b are close to the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b. The protrusion 30 is formed by, for example, embossing.

  The first seal member 36 is integrated with the surfaces 16a and 16b of the first metal separator 16 by baking or injection molding around the outer peripheral end of the first metal separator 16. The first seal member 36 uses, for example, a seal material such as EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushion material, or a packing material. To do.

  The first seal member 36 communicates the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b with the oxidant gas flow channel 26 on the surface 16a of the first metal separator 16 and surrounds them. On the surface 16b of the first metal separator 16, the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b are formed so as to communicate with a cooling medium flow path 50 described later.

  As shown in FIGS. 1 and 5, the surface 18a of the second metal separator 18 facing the electrolyte membrane / electrode structure 14 communicates with a fuel gas inlet communication hole 24a and a fuel gas outlet communication hole 24b, and an arrow A fuel gas flow path (reactive gas flow path) 40 that constitutes a meandering flow path that is folded back and forth by half in the B direction is formed.

  The fuel gas flow path 40 includes a plurality of grooves 42 provided by forming the second metal separator 18 into a wave shape. The plurality of groove portions 42 extend substantially linearly in the direction of the arrow B, and the plurality of protrusions 44a and 44b are located on both sides of the arrow B direction so as to protrude toward the surfaces 18a and 18b, respectively, by embossing, for example. Provided. On the surface 18a, folding partition members 46a and 46b are spaced apart from each other in the direction of the arrow C and arranged in a staggered manner, and the partition members 46a and 46b are made of, for example, a seal member, and each of the folding portions 48a is folded to the short side. , 48b are provided. The folded portions 48a and 48b are close to the cooling medium outlet communication hole 22b and the cooling medium inlet communication hole 22a.

  As shown in FIGS. 1 and 6, a cooling medium inlet communication hole 22 a and a cooling medium outlet are provided between a surface 18 b opposite to the surface 18 a of the second metal separator 18 and a surface 16 b of the first metal separator 16. A cooling medium flow path 50 communicating with the communication hole 22b is formed.

  The cooling medium flow path 50 includes a plurality of grooves (straight flow paths) 52 extending substantially linearly in the direction of arrow B, and a plurality of protrusions 44b are provided on both sides of the groove 52 in the direction of arrow B. It is done. The plurality of protrusions 44b contact the surface 16b of the first metal separator 16 to provide flow paths (buffer portions) 53a and 53b that connect the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b to the plurality of grooves 52, respectively. Configure (see FIG. 3).

  The second seal member 54 is integrated with the surfaces 18a and 18b of the second metal separator 18 around the outer peripheral end of the second metal separator 18. The second seal member 54 is made of the same material as the first seal member 36 described above. The second seal member 54 communicates and surrounds the fuel gas passage 40, the fuel gas inlet communication hole 24a, and the fuel gas outlet communication hole 24b on the surface 18a of the second metal separator 18 (see FIG. 5). . The second seal member 54 communicates and surrounds the cooling medium flow path 50, the cooling medium inlet communication hole 22a, and the cooling medium outlet communication hole 22b on the surface 18b (see FIG. 6).

  As shown in FIG. 1, the electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 60 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side sandwiching the solid polymer electrolyte membrane 60 The electrode 62 and the cathode side electrode 64 are provided. The outer peripheral edge of the solid polymer electrolyte membrane 60 protrudes outward from the outer peripheral ends of the anode side electrode 62 and the cathode side electrode 64.

  The anode side electrode 62 and the cathode side electrode 64 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. And have. The electrode catalyst layers are bonded to both surfaces of the solid polymer electrolyte membrane 60 so as to face each other with the solid polymer electrolyte membrane 60 interposed therebetween.

  The operation of the power generation cell 10 configured as described above will be described below.

  First, 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.

  For this reason, as shown in FIG. 5, the fuel gas is introduced into the fuel gas flow path 40 of the second metal separator 18 from the fuel gas inlet communication hole 24a, and reciprocally moves in the direction of arrow B, while the electrolyte membrane / electrode structure. It is supplied to the anode side electrode 62 constituting the body 14. On the other hand, as shown in FIGS. 1 and 4, the oxidant gas is introduced into the oxidant gas flow path 26 of the first metal separator 16 from the oxidant gas inlet communication hole 20a and reciprocates in the direction of arrow B. It is supplied to the cathode side electrode 64 constituting the electrolyte membrane / electrode structure 14.

  Therefore, in the electrolyte membrane / electrode structure 14, the fuel gas supplied to the anode side electrode 62 and the oxidant gas supplied to the cathode side electrode 64 are consumed by an electrochemical reaction in the electrode catalyst layer, thereby generating power. Is done.

  Next, the consumed fuel gas supplied to the anode side electrode 62 is discharged in the direction of arrow A along the fuel gas outlet communication hole 24b. Similarly, the oxidant gas consumed by being supplied to the cathode side electrode 64 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 20b.

  The cooling medium supplied to the cooling medium inlet communication hole 22a is introduced into the cooling medium flow path 50 formed between the first and second metal separators 16 and 18, and then flows in the direction of arrow B. This cooling medium is discharged from the cooling medium outlet communication hole 22b after the electrolyte membrane / electrode structure 14 is cooled.

  In this case, in the present embodiment, as shown in FIG. 5, a plurality of protrusions 44 a are formed on the folded portions 48 b and 48 a of the fuel gas flow path 40 adjacent to the cooling medium inlet communication hole 22 a and the cooling medium outlet communication hole 22 b. 44b is provided to protrude in different directions. Therefore, on the surface 18b of the second metal separator 18, as shown in FIG. 6, flow paths 53a and 53b are formed correspondingly between the protrusions 44b, and the flow paths 53a and 53b communicate with the cooling medium inlet. The buffer part which connects the hole 22a and the cooling-medium exit communication hole 22b, and the some groove part 52 is comprised.

  Therefore, even if the fuel gas flow path 40 configured in a meandering flow path shape is provided on one surface 18 a of the second metal separator 18, the fuel gas flow is not detected on the other surface 18 b of the second metal separator 18. The cooling medium can be supplied directly to the cooling medium flow path 50 from the cooling medium inlet communication hole 22a without being restricted by the shape of the passage 40. Similarly, the cooling medium can be discharged directly from the cooling medium flow path 50 to the cooling medium outlet communication hole 22b.

  Accordingly, by providing the flow paths 53a and 53b including the plurality of protrusions 44b on the surface 18b corresponding to the folded portions 48b and 48a of the surface 18a, the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b are provided. A degree of freedom in layout and shape layout is ensured.

  In addition, since the cooling medium is once supplied to the flow path 53a that is the buffer section, the cooling medium is uniformly distributed to the plurality of grooves 52 that constitute the cooling medium flow path 50. Therefore, the electrolyte membrane / electrode structure 14 does not generate a reaction distribution or local condensation due to a non-uniform flow of the cooling medium, and further, the durability of the electrolyte membrane / electrode structure 14 due to heat generation. It is possible to effectively prevent the decrease in sex.

  Further, the power generation cell 10 has an oxidant gas inlet communication hole 20a, a cooling medium outlet communication hole 22b, and a fuel gas outlet communication hole 24b formed at one end edge (first side) in the horizontal direction, as well as in other horizontal directions. A fuel gas inlet communication hole 24a, a cooling medium inlet communication hole 22a, and an oxidant gas outlet communication hole 20b are formed at the end edge (second side). For this reason, the power generation cell 10 can satisfactorily shorten the height direction (interval between the third and fourth sides), and the height dimension of the entire power generation cell 10 can be suppressed. In particular, the configuration is suitable for mounting under the floor.

  Furthermore, since the cooling medium flow path 50 includes a plurality of grooves (straight flow paths) 52 that connect the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b, the inside of the electrode surface is uniformly cooled. In addition, there is an advantage that local condensation or heat generation in the oxidant gas passage 26 and the fuel gas passage 40 can be prevented.

  The oxidant gas inlet communication hole 20a and the fuel gas inlet communication hole 24a are disposed above the oxidant gas outlet communication hole 20b and the fuel gas outlet communication hole 24b. Thereby, the generated water droplets existing in the oxidant gas flow channel 26 and the fuel gas flow channel 40 are favorably discharged to the oxidant gas outlet communication hole 20b and the fuel gas outlet communication hole 24b by gravity.

It is a principal part disassembled perspective explanatory drawing of the electric power generation cell which comprises the internal manifold type fuel cell which concerns on embodiment of this invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional explanatory view of the fuel cell taken along line III-III in FIG. 1. It is front explanatory drawing of the 1st metal separator which comprises the said electric power generation cell. It is front explanatory drawing of one surface of the 2nd metal separator which comprises the said electric power generation cell. It is front explanatory drawing of the other surface of the 2nd metal separator which comprises the said electric power generation cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Power generation cell 12 ... Fuel cell 14 ... Electrolyte membrane electrode assembly 16, 18 ... Metal separator 16a, 16b, 18a, 18b ... Surface 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 ... Oxidant gas flow path 28, 42, 52 ... Groove part 30, 44a, 44b ... Projection part 34a, 34b , 48a, 48b ... folded portions 36, 54 ... sealing member 40 ... fuel gas channel 50 ... cooling medium channel 53a, 53b ... channel 60 ... solid polymer electrolyte membrane 62 ... anode side electrode 64 ... cathode side electrode

Claims (2)

A power generation cell having an electrolyte membrane / electrode structure in which an electrolyte membrane is disposed between a pair of electrodes and a pair of plate-like metal separators sandwiching the electrolyte membrane / electrode structure, the electrolyte membrane / electrode structure, A reaction gas flow path for supplying a reaction gas along the electrode surface is formed between the metal separator and a cooling medium flow path for supplying a cooling medium between the power generation cells stacked in the horizontal direction. An internal manifold type fuel cell in which the power generation cell is provided with a reaction gas communication hole penetrating in the stacking direction and communicating with the reaction gas flow channel and a cooling medium communication hole communicating with the cooling medium flow channel. There,
The power generation cell includes a fuel gas communication hole and an oxidant gas communication hole, which are the reaction gas communication holes, and the fuel gas communication hole and the oxidation gas, on first and second sides facing each other in the horizontal direction. And the cooling medium communication hole is formed between the agent gas communication holes,
The cooling medium flow path includes a linear flow path that communicates the cooling medium communication holes on the first and second sides,
The metal separator is provided with the reactive gas flow path in a meandering flow path shape having a plurality of grooves and folded portions that are linearly formed on both surfaces by press molding, and
Between the metal separators that constitute adjacent power generation cells and are adjacent to each other, the cooling medium flow path is formed by overlapping the back surfaces of the reaction gas flow paths,
The folded portion that is folded at least in the vicinity of the cooling medium communication hole includes a plurality of protrusions protruding toward the reaction gas flow path and a plurality of protrusions protruding toward the cooling medium flow path. An internal manifold type fuel cell, wherein the cooling medium is circulated between the cooling medium communication hole and the cooling medium flow path.   2. The fuel cell according to claim 1, wherein each of the fuel gas communication hole and the oxidant gas communication hole has a gas inlet side communication hole disposed above the gas outlet side communication hole. Type fuel cell.

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