JP2008293694A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable uniform reactant gas supply from a reactant gas communicating hole to the whole surface of a reactant gas passage, and to secure a desired power generation performance using a simple structure. <P>SOLUTION: The fuel cell 10 includes a first metallic separator 18 and a second metallic separator 20, between which an electrolyte membrane-electrode structure 16 is held. The first metallic separator 18 is provided with a fuel gas supply communicating hole 24a, which communicates with a fuel gas passage 34 and flows a fuel gas flows in the laminating direction; and an inlet buffer portion 36a connecting the fuel gas passage 34 and the fuel gas supply communicating hole 24a. The fuel gas passage 34 is provided with a plurality of sinuous passage grooves 34a, where the sinuous passage grooves 34a which are adjacent each other are constituted so that end positions facing the inlet buffer portion 36a are in a mutually stepped difference form. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are laminated, and a reaction gas flow path for supplying a reaction gas is formed along the electrode surface. The present invention relates to a fuel cell in which a reaction gas communication hole for flowing gas in a stacking direction is formed.

  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 disposed on both sides of an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane is sandwiched by separators. It has a power generation cell. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of power generation cells.

  In the fuel cell described above, a fuel gas flow path (hereinafter also referred to as a reaction gas flow path) for flowing a fuel gas to the anode side electrode and an oxidation for flowing an oxidant gas to the cathode side electrode in the plane of the separator. An agent gas channel (hereinafter also referred to as a reaction gas channel) is provided. Furthermore, a cooling medium flow path for flowing a cooling medium is provided along the surface direction of the separator for each power generation cell or for each of the plurality of power generation cells.

  The fuel cell may constitute a so-called internal manifold in which a reaction gas communication hole and a cooling medium communication hole penetrating in the stacking direction of the separator are provided inside the fuel cell. At this time, generally, a buffer portion is provided between the reaction gas communication hole and the reaction gas channel so as to uniformly distribute and supply the reaction gas to the reaction gas channel.

  For example, in Patent Document 1, as shown in FIG. 7, an oxidant gas inlet manifold 2a, a refrigerant inlet manifold 3a, and a fuel gas inlet manifold 4a are formed through one end edge of the sheet metal element 1 in the longitudinal direction. . An oxidant gas outlet manifold 2b, a refrigerant outlet manifold 3b, and a fuel gas outlet manifold 4b are formed through the other end of the sheet metal element 1 in the longitudinal direction.

  A corrugated flow path 5 is formed on the fuel gas supply surface side of the sheet metal element 1, and an inlet buffer section 6a and an outlet buffer section 6b made of dimples are provided at both ends of the corrugated flow path 5, respectively. ing. The corrugated flow path 5 has a plurality of linear flow path grooves 5a.

Japanese translation of PCT publication No. 2002-530836

  In the above-mentioned Patent Document 1, the fuel gas inlet manifold 4a is provided close to one end side in the width direction (arrow H direction) of the sheet metal element 1. Therefore, when the fuel gas supplied from the fuel gas inlet manifold 4a to the inlet buffer 6a is dispersed in the width direction of the corrugated flow path 5, the gas flow rate at the center side in the width direction of the corrugated flow path 5 is particularly large. It tends to be lower than the gas flow rate at both ends in the width direction.

  Accordingly, there is a problem that the fuel gas cannot be uniformly distributed over the entire surface of the corrugated flow path 5 and the power generation performance is deteriorated, and for example, deterioration of the solid polymer electrolyte membrane is caused.

  The present invention solves this type of problem, and with a simple configuration, the reaction gas can be uniformly supplied from the reaction gas communication hole to the entire surface of the reaction gas flow path, thereby ensuring the desired power generation performance. An object is to provide a possible fuel cell.

  In the present invention, an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are laminated, and a reaction gas flow path for supplying a reaction gas is formed along the electrode surface. The present invention relates to a fuel cell in which a reaction gas communication hole for flowing gas in a stacking direction is formed.

  The separator is provided with an inlet buffer portion located on the inlet side of the reaction gas flow path and a supply side of the reaction gas communication hole located along one ridge line side of the inlet buffer portion. The reaction gas channel includes a plurality of channel grooves that have a linear shape or a wave shape and extend in one direction, and the channel grooves that are adjacent to each other at least in the center in the width direction of the reaction gas channel are The positions of the end portions on the inlet buffer portion side are formed in steps.

  The plurality of flow channel grooves are preferably arranged in a staggered manner with the end portions on the inlet buffer portion side protruding alternately.

  Further, the separator corresponds to the outlet buffer portion located on the outlet side of the reactive gas flow path, the supply side of the reactive gas communication hole, and the point target position, and is positioned along one ridge line side of the outlet buffer portion. It is preferable that the outlet side of the reaction gas communication hole is provided, and the end position of the adjacent channel groove on the outlet buffer part side is configured to be stepped.

  According to the present invention, the end positions on the inlet buffer portion side of the flow channel grooves that constitute the reaction gas flow channel and are adjacent to each other are formed in steps. For this reason, the reaction gas can be guided to the flow channel through the stepped portion of the flow channel, particularly on the center side in the width direction of the reaction gas flow channel where the reactive gas easily passes along the inlet buffer. it can. Accordingly, the reaction gas can be uniformly supplied from the reaction gas communication hole to the entire surface of the reaction gas channel with a simple configuration, and desired power generation performance can be ensured.

  In addition, since the end positions of the channel grooves adjacent to each other are configured in steps, the reaction gas comes into contact with the mountain-shaped portion constituting the end protruding toward the inlet buffer portion, and the flow of the reaction gas The direction changes.

  Therefore, the flow rate of the reaction gas flowing through the flow channel groove having the end protruding to the inlet buffer portion side is higher than the flow rate of the reaction gas flowing through the flow channel groove having the end located inside the stepped portion. Become fast. For this reason, a relatively large flow velocity difference is caused between adjacent channel grooves, and the reaction gas moves between the channel grooves beyond the mountain-shaped portion, and the gas diffusibility in the mountain-shaped portion is improved satisfactorily. To do. Thereby, the power generation performance can be improved.

  FIG. 1 is an exploded perspective view of a fuel cell 10 according to a first embodiment of the present invention, and FIG. 2 is a sectional view of the fuel cell 10 taken along line II-II in FIG.

  As shown in FIG. 1, in the fuel cell 10, an electrolyte membrane / electrode structure 16 is sandwiched between a first metal separator 18 on the anode side and a second metal separator 20 on the cathode side. The first and second metal separators 18 and 20 have a concavo-convex shape by pressing a metal thin plate into a wave shape.

  The first and second metal separators 18 and 20 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface is subjected to anticorrosion treatment. Moreover, instead of the first and second metal separators 18 and 20, for example, a carbon separator may be adopted.

  An oxidant gas supply for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the direction of the arrow A at the upper edge of the long side direction (the direction of arrow C in FIG. 1) of the fuel cell 10. A communication hole (reaction gas communication hole) 22a and a fuel gas supply communication hole (reaction gas communication hole) 24a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The lower end edge of the long side direction of the fuel cell 10 communicates with each other in the direction of the arrow A, and a fuel gas discharge communication hole (reaction gas communication hole) 24b for discharging the fuel gas and an oxidant gas are discharged. An oxidant gas discharge communication hole (reaction gas communication hole) 22b is provided. The oxidant gas supply communication hole 22a and the oxidant gas discharge communication hole 22b are provided corresponding to the positions to be pointed, and the fuel gas supply communication hole 24a and the fuel gas discharge communication hole 24b are similarly pointed. Are provided corresponding to the positions.

  At one edge of the fuel cell 10 in the short side direction (arrow B direction), there is provided a cooling medium supply communication hole 26a that communicates with each other in the arrow A direction and supplies a cooling medium. A cooling medium discharge communication hole 26b for discharging the cooling medium is provided at the other end edge.

  The electrolyte membrane / electrode structure 16 includes, for example, a solid polymer electrolyte membrane 28 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 30 and a cathode side electrode 32 that sandwich the solid polymer electrolyte membrane 28. With. The anode side electrode 30 has a smaller surface area than the cathode side electrode 32.

  The anode-side electrode 30 and the cathode-side electrode 32 are uniformly coated with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof. An electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 28.

  A fuel gas flow path 34 that connects the fuel gas supply communication hole 24 a and the fuel gas discharge communication hole 24 b is formed on the surface 18 a of the first metal separator 18 facing the electrolyte membrane / electrode structure 16. As shown in FIG. 3, the fuel gas channel 34 has a plurality of wave-like channel grooves 34a extending in the direction of arrow C, and is located at the upper and lower ends of the wave-like channel groove 34a in the direction of arrow C. An inlet buffer part 36a and an outlet buffer part 36b are provided.

  The inlet buffer portion 36a and the outlet buffer portion 36b have a substantially triangular shape and are provided with a plurality of embosses 38a and 38b. The fuel gas supply communication hole 24a is located along one ridge line side of the inlet buffer portion 36a (arrow B1 direction side), and the fuel gas discharge communication hole 24b is one of the outlet buffer portions 36b (arrow B2 direction). Located along the ridgeline side.

  At least on the center side in the width direction (arrow B direction) of the fuel gas flow channel 34, in the first embodiment, the wavy flow channel grooves 34a adjacent to each other in the entire width direction of the fuel gas flow channel 34 are formed in the inlet buffer portion. The end positions on the 36a side are formed in steps. Specifically, the upper end positions of the mountain-shaped portions 40a and 40b forming the wave-shaped flow channel grooves 34a are alternately arranged in the arrow B direction so as to protrude toward the inlet buffer portion 36a and arranged in a staggered manner. For example, the mountain shape portion 40b constitutes an outer end portion protruding toward the inlet buffer portion 36a, while the mountain shape portion 40a constitutes an inner end portion located inward of the mountain shape portion 40b.

  The surface 18a of the first metal separator 18 has a plurality of receiving portions 41a for forming a communication path that communicates the fuel gas supply communication hole 24a and the inlet buffer portion 36a, a fuel gas discharge communication hole 24b, and an outlet buffer portion 36b. And a plurality of receiving portions 41b for forming communication passages communicating with each other. A plurality of supply hole portions 42a and discharge hole portions 42b are formed in the vicinity of the receiving portions 41a and 41b, respectively. The supply hole portion 42a communicates with the fuel gas supply communication hole 24a on the surface 18b side, while the discharge hole portion 42b similarly communicates with the fuel gas discharge communication hole 24b on the surface 18b side.

  As shown in FIG. 4, an oxidant gas supply communication hole 22a and an oxidant gas discharge communication hole 22b are communicated with the surface 20a of the second metal separator 20 facing the electrolyte membrane / electrode structure 16 through an oxidant gas. A flow path 44 is formed. The oxidant gas channel 44 has a plurality of wave-like channel grooves 44a extending in the direction of the arrow C, and is located at the upper and lower ends of the wave-like channel groove 44a in the direction of the arrow C. A buffer unit 46b is provided.

  The inlet buffer portion 46a and the outlet buffer portion 46b have a plurality of embosses 48a and 48b. The oxidant gas supply communication hole 22a is located along the ridge line side of one of the inlet buffer portions 46a (in the direction of arrow B2), and the oxidant gas discharge communication hole 22b is one of the outlet buffer portions 46b (in the direction of arrow B1). ) Along the ridgeline side.

  At least on the center side in the width direction (arrow B direction) of the oxidant gas flow path 44, in the first embodiment, the wavy flow path grooves 44a adjacent to each other in the entire width direction of the oxidant gas flow path 44 are The end positions on the buffer section 46a side are formed in steps. Specifically, the mountain-shaped portions 50a and 50b that form the respective wavy flow channel grooves 44a and are alternately arranged in the direction of arrow B are set to have different lengths and are arranged in a staggered manner. For example, the mountain-shaped portion 50b constitutes an outer end portion protruding toward the inlet buffer portion 46a, while the mountain-shaped portion 50a constitutes an inner end portion located inward of the mountain-shaped portion 50b. Yes.

  The surface 20a communicates with a plurality of receiving portions 51a for communicating with the oxidant gas supply communication hole 22a and the inlet buffer portion 46a, and with the oxidant gas discharge communication hole 22b and the outlet buffer portion 46b. A plurality of receiving portions 51b for forming a passage are provided.

  As shown in FIG. 1, the cooling medium communicating with the cooling medium supply communication hole 26 a and the cooling medium discharge communication hole 26 b between the surface 20 b of the second metal separator 20 and the surface 18 b of the first metal separator 18. A flow path 54 is formed. The cooling medium channel 54 is formed to extend in the direction of arrow B by overlapping the back surface shape of the fuel gas channel 34 and the back surface shape of the oxidant gas channel 44.

  A first seal member 56 is integrally formed on the surfaces 18 a and 18 b of the first metal separator 18 around the outer peripheral edge of the first metal separator 18. A second seal member 58 is integrally formed on the surfaces 20 a and 20 b of the second metal separator 20 so as to go around the outer peripheral edge of the second metal separator 20. As the first and second sealing members 56, 58, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material, Alternatively, a packing material is used.

  As shown in FIGS. 1 and 3, the first seal member 56 includes a seal portion 56a provided on the surface 18a side so as to surround the fuel gas flow path 34, and a seal portion 56b provided outside the seal portion 56a. And have. The seal portion 56a constitutes a convex seal that goes around the fuel gas flow path 34, the inlet buffer portion 36a, the outlet buffer portion 36b, the supply hole portion 42a, and the discharge hole portion 42b.

  As shown in FIG. 4, the second seal member 58 is formed on the surface 20a side of the second metal separator 20 with the oxidant gas flow path 44, the inlet buffer part 46a, the outlet buffer part 46b, the oxidant gas supply communication hole 22a, and the oxidation gas. A seal portion 58a is formed so as to surround the agent gas discharge communication hole 22b.

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

  First, as shown in FIG. 1, in the fuel cell 10, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 22a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 24a. Is supplied. Further, a coolant such as pure water or ethylene glycol is supplied to the coolant supply passage 26a.

  The oxidant gas is introduced into the oxidant gas flow path 44 of the second metal separator 20 from the oxidant gas supply communication hole 22 a and moves along the cathode side electrode 32 of the electrolyte membrane / electrode structure 16.

  At that time, as shown in FIG. 4, on the surface 20a of the second metal separator 20, the oxidant gas flowing through the oxidant gas supply communication hole 22a is supplied to the inlet buffer part 46a through the plurality of receiving parts 51a. The The oxidant gas supplied to the inlet buffer 46a is dispersed in the direction of arrow B and flows vertically downward along the plurality of undulating channel grooves 44a constituting the oxidant gas channel 44. It is supplied to the cathode side electrode 32 of the membrane / electrode structure 16.

  On the other hand, as shown in FIGS. 1 and 3, the fuel gas is supplied to the surface 18 a side through the plurality of supply holes 42 a from the fuel gas supply communication holes 24 a on the surface 18 b of the first metal separator 18. The fuel gas is introduced into the inlet buffer portion 36a through the receiving portion 41a. The fuel gas dispersed in the direction of the arrow B by the inlet buffer portion 36a moves vertically downward along the plurality of wave-like channel grooves 34a constituting the fuel gas channel 34, and the anode of the electrolyte membrane / electrode structure 16 It is supplied to the side electrode 30.

  Therefore, in each electrolyte membrane / electrode structure 16, the oxidant gas supplied to the cathode side electrode 32 and the fuel gas supplied to the anode side electrode 30 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed (see FIG. 2).

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 32 is sent to an outlet buffer part 46 b communicating with the lower part of the oxidant gas flow path 44 as shown in FIG. 4. Further, the oxidant gas is discharged from the outlet buffer part 46b to the oxidant gas discharge communication hole 22b along the space between the plurality of receiving parts 51b.

  Similarly, as shown in FIGS. 1 and 3, the fuel gas that is consumed by being supplied to the anode electrode 30 is sent to an outlet buffer portion 36 b that communicates with the lower portion of the fuel gas flow path 34, and then a plurality of fuel gases are supplied. It flows between the receiving parts 41b. The fuel gas passes through the plurality of discharge holes 42b and moves toward the surface 18b, and is discharged to the fuel gas discharge communication hole 24b.

  The cooling medium flows in the direction of arrow B (horizontal direction) after being introduced into the cooling medium flow path 54 between the first and second metal separators 18 and 20 from the cooling medium supply communication hole 26a. The cooling medium is discharged from the cooling medium discharge communication hole 26b after the electrolyte membrane / electrode structure 16 is cooled.

  In this case, in the first embodiment, as shown in FIG. 4, the end portion positions on the inlet buffer portion 46a side of the wavy flow channel grooves 44a that constitute the oxidant gas flow channel 44 and are adjacent to each other are stepped. It is configured. That is, the mountain-shaped portions 50a and 50b that form the wave-shaped channel grooves 44a are alternately arranged in a staggered manner with different heights.

  Therefore, when the oxidant gas supplied from the oxidant gas supply communication hole 22a to the inlet buffer 46a is dispersed in the direction of the arrow B1 along the inlet buffer 46a, the oxidant gas particularly easily passes therethrough. On the central side in the width direction of the oxidant gas flow channel 44, the flow direction is changed by the mountain-shaped portions 50a and 50b arranged in a staggered manner, and the oxidant gas flow channel 44 is smoothly guided to the respective wavy flow channel grooves 44a.

  As a result, the oxidant gas can be uniformly supplied from the oxidant gas supply communication hole 22a over the entire surface of the oxidant gas flow path 44 with a simple configuration, and desired power generation performance can be ensured. An effect is obtained.

  In addition, the oxidant gas supplied from the oxidant gas supply passage 22a provided at the upper end of the oxidant gas flow path 44 in the direction of the arrow B2 moves when the inlet buffer 46a moves in the direction of the arrow B1. It is easy to collide with the mountain-shaped portion 50b protruding upward.

  For this reason, as shown in FIG. 5, the oxidant gas that has come into contact with the mountain-shaped portion 50a is forcibly introduced into the wave-shaped channel groove 44a1, while the wave-shaped channel groove 44a2 downstream of the mountain-shaped portion 50b. The oxidant gas is difficult to flow. Therefore, the oxidant gas flowing through the wavy flow channel groove 44a1 passes over the mountain-shaped portions 50a and 50b and is adjacent to the wavy flow channel 44a2 due to the flow rate difference between the wavy flow channel groove 44a1 having a high flow rate and the wavy flow channel groove 44a2 having a low flow rate. It moves to the channel groove 44a2.

  Thereby, in 1st Embodiment, the diffusibility of oxidant gas in the mountain-shaped parts 50a and 50b improves favorably, and there exists an advantage that the improvement of electric power generation performance is performed easily.

  FIG. 6 is an explanatory front view of the second metal separator 60 constituting the fuel cell according to the second embodiment of the present invention. Note that the same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  An oxidant gas flow path 44 is formed on the surface 20 a of the second metal separator 60, and the mountain-shaped portions 62 a and 62 b constituting the plurality of wave-like flow path grooves 44 a constituting the oxidant gas flow path 44 are Are alternately provided in the direction of arrow B. The upper end position of the mountain-shaped portion 62b protrudes closer to the inlet buffer portion 46a than the upper end position of the mountain-shaped portion 62a, while the lower end position of the mountain-shaped portion 62a is the outlet buffer than the lower end position of the mountain-shaped portion 62b. It protrudes to the part 46b side. Although not shown, the fuel gas flow path is similarly configured.

  In the second embodiment, as shown in FIG. 6, the mountain-shaped portions 62a and 62b are set to have the same length in the direction of the arrow C, and the channel length of each wave-like channel groove 44a is set to the same dimension. Can be set. In addition, the end position of the wave-like channel groove 44a on the outlet buffer portion 46b side is formed in a step shape. For this reason, it is possible to reliably prevent water from staying at the lower end of the wave-like channel groove 44a, improve drainage, and maintain the power generation performance satisfactorily.

  In the first and second embodiments, the oxidant gas flow path 44 is composed of a plurality of wave-shaped flow path grooves 44a, but is not limited to this, and a plurality of linear flow path grooves are used. Even if configured, the same effect can be obtained.

1 is an exploded perspective view of a fuel cell according to a first embodiment of the present invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is a front view of the 1st metal separator which comprises the said fuel cell. It is a front view of the 2nd metal separator which comprises the said fuel cell. It is explanatory drawing at the time of oxidant gas being supplied to an oxidant gas flow path. It is front explanatory drawing of the 2nd metal separator which comprises the fuel cell which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the sheet metal element of patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 16 ... Electrolyte membrane electrode structure 18, 20, 60 ... Metal separator 22a ... Oxidant gas supply communication hole 22b ... Oxidant gas discharge communication hole 24a ... Fuel gas supply communication hole 24b ... Fuel gas discharge communication hole 26a ... Cooling medium supply communication hole 26b ... Cooling medium discharge communication hole 28 ... Solid polymer electrolyte membrane 30 ... Anode side electrode 32 ... Cathode side electrode 34 ... Fuel gas flow path 34a, 44a ... Wave-shaped flow path grooves 36a, 46a ... Inlet Buffer part 36b, 46b ... Outlet buffer part 40a, 40b, 50a, 50b, 62a, 62b ... Mountain-shaped part 42a ... Supply hole part 42b ... Discharge hole part 44 ... Oxidant gas flow path 54 ... Cooling medium flow path

Claims (3)

An electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and a separator are stacked, and a reaction gas flow path for supplying a reaction gas along the electrode surface is formed, and the reaction gas is stacked in the stacking direction. A fuel cell in which a reaction gas communication hole to be circulated is formed,
In the separator, an inlet buffer portion located on the inlet side of the reaction gas flow path,
A supply side of the reaction gas communication hole located along one ridge line side of the inlet buffer unit;
Is provided,
The reaction gas flow path includes a plurality of flow path grooves having a linear shape or a wavy shape and extending in one direction, and the flow path grooves adjacent to each other at least in the width direction center side of the reaction gas flow path are: The fuel cell according to claim 1, wherein end positions on the inlet buffer side are formed in steps.   2. The fuel cell according to claim 1, wherein the plurality of flow channel grooves are arranged in a staggered manner with the end portions on the inlet buffer portion side protruding alternately. The fuel cell according to claim 1 or 2, wherein the separator includes an outlet buffer portion located on an outlet side of the reaction gas flow path,
The discharge side of the reaction gas communication hole corresponding to the supply side of the reaction gas communication hole and the position of the point object, and positioned along one ridge line side of the outlet buffer unit,
Is provided,
The fuel cell according to claim 1, wherein end positions on the outlet buffer side of the adjacent channel grooves are configured to be stepped with each other.

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