JP6170317B2 - Fuel cell - Google Patents

Description

  The present invention sandwiches an electrolyte membrane / electrode structure provided with electrodes on both sides of the electrolyte membrane by a separator and supplies a reactive gas along the electrode surface of the electrolyte membrane / electrode structure; The present invention relates to a fuel cell in which a reaction gas communication hole for flowing the reaction gas in the stacking direction of the separator is formed.

  For example, a polymer electrolyte fuel cell is an electrolyte membrane / electrode structure in which an anode electrode is disposed on one surface of a solid polymer electrolyte membrane comprising a polymer ion exchange membrane, and a cathode electrode is disposed on the other surface. (MEA). The electrolyte membrane / electrode structure is sandwiched between separators to constitute a power generation cell (unit cell). In a fuel cell, usually, several tens to several hundreds of unit cells are stacked to constitute an in-vehicle fuel cell stack.

  In the fuel cell described above, a so-called internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode electrode and the cathode electrode of each of the stacked power generation cells. The internal manifold includes a reaction gas inlet communication hole and a reaction gas outlet communication hole that are provided to penetrate in the stacking direction of the power generation cells. The reaction gas inlet communication hole and the reaction gas outlet communication hole communicate with the inlet side and the outlet side of the reaction gas flow path for supplying the reaction gas along the electrode surface.

  In this case, the reaction gas inlet communication hole and the reaction gas outlet communication hole have a relatively small opening area. Therefore, in order to smoothly flow the reaction gas in the reaction gas channel, an inlet buffer portion and an outlet buffer portion for dispersing the reaction gas are required in the vicinity of the reaction gas inlet communication hole and the reaction gas outlet communication hole. ing.

  At that time, it is difficult to uniformly distribute the reaction gas to the reaction gas flow path communicating with the inlet buffer portion and the outlet buffer portion. For this reason, for example, in the fuel cell disclosed in Patent Document 1, the pressure loss of the inlet buffer portion is set smaller than the pressure loss of the outlet buffer portion.

  Therefore, in Patent Document 1, when the reaction gas is consumed in the reaction gas flow path by power generation, the pressure loss of the inlet buffer portion and the pressure loss of the outlet buffer portion are equal. Accordingly, the reaction gas can be evenly distributed to the reaction gas flow path, and the desired power generation performance can be satisfactorily maintained with a simple configuration.

JP 2010-129265 A

  The present invention has been made in connection with a fuel cell having this type of buffer part, and can supply reaction gas uniformly and reliably from the reaction gas communication hole to the entire reaction gas flow path with a simple configuration. An object of the present invention is to provide a fuel cell capable of maintaining good power generation performance.

  The present invention sandwiches an electrolyte membrane / electrode structure provided with electrodes on both sides of the electrolyte membrane by a separator and supplies a reactive gas along the electrode surface of the electrolyte membrane / electrode structure; The present invention relates to a fuel cell in which a reaction gas communication hole for flowing the reaction gas in the stacking direction of the separator is formed.

In this fuel cell, a buffer portion is provided that communicates the reaction gas communication hole and the reaction gas channel. The buffer unit includes a first buffer region adjacent to the reaction gas flow path and a second buffer region adjacent to the reaction gas communication hole and deeper in the stacking direction than the first buffer region. The reaction gas communication hole is arranged closer to one side from the center in the width direction intersecting the flow direction of the reaction gas flow path. In the second buffer region, an end portion far from the reaction gas communication hole disposed on one side in the width direction has a greater depth in the stacking direction than an end portion close to the reaction gas communication hole in the width direction. Is formed.

Further, in this fuel cell, the second buffer area, a second buffer area body, and the shallow and deep intermediate depth buffer area in the stacking direction than the first buffer area in the stacking direction than the second buffer area body , Is provided.

Further, in this fuel cell, the first buffer region is provided with a plurality of bulging guide portions that continuously connect the reaction gas flow path and the second buffer region, and the bottom of the intermediate depth buffer region is Preferably, the second buffer region body is provided at an intermediate position between the bottom portion of the second buffer region main body and the bottom portion of the bulging guide portion.

Furthermore, bulging the fuel in the cell, the medium Mafuka of buffer area, which is located in the most one side of the bulging guide portion connected to the other side of the width direction Mukonaka central of the reaction gas channel It is preferably provided between the extension of the guide portion and the one end portion of the second buffer region main body .

Further, in this fuel cell, the reaction gas communication hole is reaction gas supply passage, inlet buffer that communicates with the previous SL reaction gas supply passage and the reactant gas flow path, one of the second buffer area body An intermediate depth buffer region is provided on the side, and the fuel cell is formed with a reaction gas outlet communication hole that is disposed from the center in the width direction toward the other side and that allows the reaction gas to flow in the stacking direction of the separator. And an outlet buffer portion that communicates the reactive gas outlet communication hole and the reactive gas flow path, and the outlet buffer portion includes a first outlet buffer region adjacent to the reactive gas flow path, and the reactive gas outlet. A second outlet buffer region adjacent to the communication hole and deeper in the stacking direction than the first outlet buffer region, and the second outlet buffer region includes a second outlet buffer region body, And deep intermediate depth outlet buffer area in the stacking direction than shallow and the first outlet buffer area in the stacking direction than the second outlet buffer area body, is provided, before Kide port buffer, said second outlet The intermediate depth outlet buffer region is provided on the one side of the buffer region body.

  Further, in this fuel cell, the second buffer region is provided with an inclined portion in which the depth in the stacking direction continuously changes from one side in the width direction of the reaction gas channel toward the other side in the width direction. .

  According to the present invention, the second buffer region adjacent to the reaction gas communication hole is set deeper (in a deep groove) in the stacking direction than the first buffer region adjacent to the reaction gas channel. For this reason, the gas distribution property of the reaction gas in the second buffer region can be improved satisfactorily.

  Therefore, for example, the reaction gas supplied from the reaction gas inlet communication hole (reaction gas communication hole) to the inlet buffer unit (buffer unit) is distributed well in the second buffer region, and then along the first buffer region. It flows and is supplied to the reaction gas channel.

  Moreover, the depth of the second buffer region in the stacking direction is different from one side in the width direction intersecting the flow direction of the reaction gas channel toward the other side in the width direction. Thereby, in the second buffer region, the pressure loss of the portion where the depth is set shallow is increased and the distribution of the reaction gas is reduced. Therefore, the position and range where the depth of the second buffer region is changed, etc. It is possible to adjust the increase / decrease in the distribution of the reaction gas.

  For this reason, with a simple configuration, the reaction gas can be uniformly and reliably supplied from the reaction gas communication hole to the entire reaction gas flow path via the buffer portion, and it is possible to maintain good power generation performance.

1 is an exploded schematic perspective view of a power generation cell constituting a fuel cell according to a first embodiment of the present invention. It is the II-II sectional view taken on the line of the said electric power generation cell in FIG. It is front explanatory drawing of the electrolyte membrane and electrode structure which comprises the said electric power generation cell. It is principal part expansion explanatory drawing of the said electrolyte membrane and electrode structure. FIG. 5 is a cross-sectional view of the resin frame member provided on the electrolyte membrane / electrode structure, taken along line VV in FIG. 4. It is the VI-VI sectional view taken on the line of the said resin frame member in FIG. It is a disassembled schematic perspective view of the electric power generation cell which comprises the fuel cell which concerns on the 2nd Embodiment of this invention. It is front explanatory drawing of the 1st separator which comprises the said electric power generation cell. It is a partial explanatory view of an electrolyte membrane and electrode structure which constitutes a fuel cell according to a third embodiment of the present invention. FIG. 10 is a cross-sectional view of the electrolyte membrane / electrode structure taken along line XX in FIG. 9.

  As shown in FIGS. 1 and 2, the fuel cell 10 according to the first embodiment of the present invention has a plurality of power generation cells 12 stacked in the horizontal direction (arrow A direction) or the gravity direction (arrow C direction). For example, it is used as an in-vehicle fuel cell stack.

  The power generation cell 12 sandwiches an electrolyte membrane / electrode structure (MEA) 18 between the first separator 14 and the second separator 16. The oxidant gas inlet communication hole (reactive gas communication hole) 20a and the fuel gas inlet communication hole (reactive gas) communicate with each other in the arrow A direction at the upper edge of the long side direction (arrow C direction) of the power generation cell 12. Communication hole) 22a is provided. The oxidant gas inlet communication hole 20a supplies an oxidant gas (reaction gas), for example, an oxygen-containing gas (air, etc.) in the direction of arrow A, while the fuel gas inlet communication hole 22a has a fuel gas (reaction gas), For example, a hydrogen-containing gas (hydrogen gas or the like) is supplied in the direction of arrow A.

  The lower end edge of the power generation cell 12 in the long side direction (arrow C direction) communicates with each other in the direction of arrow A, and includes a fuel gas outlet communication hole (reaction gas communication hole) 22b and an oxidant gas outlet communication hole (reaction gas). Communication hole) 20b is provided. The fuel gas outlet communication hole 22b discharges fuel gas in the direction of arrow A, while the oxidant gas outlet communication hole 20b discharges oxidant gas in the direction of arrow A.

  A cooling medium inlet communication hole 24a is provided at one end edge of the power generation cell 12 in the short side direction (arrow B direction) so as to communicate with each other in the arrow A direction and supply the cooling medium. A cooling medium outlet communication hole 24 b for discharging the cooling medium is provided at the other end edge in the short side direction of the power generation cell 12.

  The first separator 14 and the second separator 16 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate that has been subjected to a surface treatment for corrosion prevention on its metal surface. The 1st separator 14 and the 2nd separator 16 have cross-sectional uneven | corrugated shape by pressing a metal thin plate into a waveform. The first separator 14 and the second separator 16 may be carbon separators or the like instead of the metal separators.

  An oxidant gas flow path (reactive gas flow path) 26 that communicates the oxidant gas inlet communication hole 20a and the oxidant gas outlet communication hole 20b is formed on the surface 14a of the first separator 14 facing the electrolyte membrane / electrode structure 18. Is formed. The oxidant gas channel 26 has a plurality of wave-like channel grooves (or linear channel grooves) extending in the direction of arrow C. A part of the cooling medium flow path 28 that connects the cooling medium inlet communication hole 24 a and the cooling medium outlet communication hole 24 b is formed on the surface 14 b of the first separator 14. The cooling medium channel 28 is configured by overlapping the back surface shape of the oxidant gas channel 26 and the back surface shape of the fuel gas channel 32 described later.

  A fuel gas flow path 32 that connects the fuel gas inlet communication hole 22a and the fuel gas outlet communication hole 22b is formed on the surface 16a of the second separator 16 facing the electrolyte membrane / electrode structure 18. The fuel gas channel 32 has a plurality of wave-shaped channel grooves (or straight channel grooves) extending in the direction of arrow C. A part of the cooling medium flow path 28 that connects the cooling medium inlet communication hole 24 a and the cooling medium outlet communication hole 24 b is formed on the surface 16 b of the second separator 16.

  Sealing members (not shown) may be provided on both surfaces 14a and 14b of the first separator 14 and both surfaces 16a and 16b of the second separator 16 as necessary.

  As shown in FIG. 2, the electrolyte membrane / electrode structure 18 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode sandwiching the solid polymer electrolyte membrane 36 38 and an anode electrode 40. The cathode electrode 38 and the anode electrode 40 are formed by uniformly applying 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 to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 36.

  The solid polymer electrolyte membrane 36 is set to have the same planar dimension as the cathode electrode 38 and the anode electrode 40 or a larger planar dimension than these. A resin frame member (frame portion) 42 is integrally formed by, for example, injection molding or a separate part is joined to the outer peripheral edge of the solid polymer electrolyte membrane 36. As the resin material, for example, engineering plastics, super engineering plastics, etc. are adopted in addition to general-purpose plastics.

  As shown in FIGS. 1 and 3, in the electrolyte membrane / electrode structure 18, the oxidant gas inlet communication hole 20 a, the fuel gas inlet communication hole 22 a, the cooling medium inlet communication hole 24 a, and the oxidant gas outlet are formed in the resin frame member 42. A communication hole 20b, a fuel gas outlet communication hole 22b, and a cooling medium outlet communication hole 24b are formed.

  As shown in FIG. 3, the surface 42a of the resin frame member 42 on which the cathode electrode 38 is provided has a plurality of inlet side connection grooves 44a having one end communicating with the oxidant gas inlet communication hole 20a, and an oxidant gas outlet communication hole. A plurality of outlet side connection grooves 44b whose one ends communicate with 20b are provided. The other end of the inlet side connecting groove 44 a communicates with the inlet buffer portion 46, while the other end of the outlet side connecting groove 44 b communicates with the outlet buffer portion 48.

  As shown in FIG. 4, the inlet side connecting grooves 44 a are set to have a uniform length S and a uniform width dimension h, and the same pressure loss. Similarly, each outlet-side connecting groove 44b is set to have a uniform length and a uniform width, and the same pressure loss.

  The inlet buffer unit 46 communicates the oxidant gas inlet communication hole 20 a and the oxidant gas flow path 26. The outlet buffer 48 communicates the oxidant gas flow path 26 and the oxidant gas outlet communication hole 20b.

  The inlet buffer unit 46 has a substantially triangular shape, and includes a first buffer region 46a adjacent to the oxidant gas flow channel 26 and a second buffer region 46b adjacent to the oxidant gas inlet communication hole 20a. The first buffer region 46a is provided with a plurality of bulging guide portions 50 that continuously connect the oxidant gas flow path 26 and the second buffer region 46b.

  Each bulge guide part 50 has a thin plate shape, and is arranged substantially evenly along the width direction (arrow B direction) of the oxidant gas flow path 26 in parallel with each other. As shown in FIG. 5, the first buffer region 46a has a depth D1 in the stacking direction (arrow A direction) from the surface 42a (depth from the tip to the bottom of the bulging guide portion 50).

  As shown in FIGS. 3 and 4, the second buffer region 46b is formed in parallel with the inner end face of the oxidizing gas inlet communication hole 20a and is elongated in the arrangement direction of the inlet side connecting grooves 44a. The second buffer region 46b has a width dimension on one end side of the electrolyte membrane / electrode structure 18 (the end side where the oxidant gas inlet communication hole 20a is provided) (in the direction of the arrow B1). It is set to a dimension smaller than the width dimension on the other end side (arrow B2 direction) opposite to the end side. The second buffer region 46b has a substantially trapezoidal shape, and the width dimension increases continuously in the direction of the arrow B2.

  As shown in FIG. 5, the second buffer region 46b has a depth D2 in the stacking direction (arrow A direction) from the surface 42a. The depth D2 of the second buffer region 46b is larger than the depth D1 of the first buffer region 46a, that is, a deep groove is set (D2> D1). An embossed portion 52 is provided in the second buffer area 46b.

  An intermediate depth buffer region 46bm that is shallower in the stacking direction than the second buffer region 46b and deeper in the stacking direction than the first buffer region 46a is provided on the end side in the arrow B1 direction of the second buffer region 46b. . The depth D3 of the intermediate depth buffer region 46bm has a relationship of D1 <D3 <D2.

  The intermediate depth buffer region 46 bm is provided at an intermediate position between the bottom portion of the second buffer region 46 b and the bottom portion of the bulging guide portion 50. The distance t1 between the bottom of the second buffer area 46b and the bottom of the intermediate depth buffer area 46bm, and the distance t2 between the bottom of the intermediate depth buffer area 46bm and the bottom of the first buffer area 46a have a relationship of t1 = t2. Set to

  As shown in FIG. 3, the oxidant gas inlet communication hole 20a is formed on one side (in the direction of arrow B1) from the central region in the width direction (in the direction of arrow B) that intersects the flow direction (in the direction of arrow C) of the oxidant gas channel 26. ). The intermediate depth buffer region 46bm is located between the extension of the bulging guide portion 50mid1 connected to the central region in the width direction of the oxidant gas flow channel 26 and the one end portion of the second buffer region 46b. Provided.

  The outlet buffer portion 48 has a substantially triangular shape, and includes a first buffer region 48a adjacent to the oxidant gas flow channel 26 and a second buffer region 48b adjacent to the oxidant gas outlet communication hole 20b. The first buffer region 48a is provided with a plurality of bulging guide portions 50 that continuously connect the oxidant gas flow path 26 and the second buffer region 46b.

  The second buffer region 48b is parallel to the inner end face of the oxidizing gas outlet communication hole 20b and is formed long in the arrangement direction of the outlet side connecting grooves 44b. The second buffer region 48b has a width dimension on the other end side of the electrolyte membrane / electrode structure 18 (the end side where the oxidant gas outlet communication hole 20b is provided) (in the direction of arrow B2). It is set to a dimension smaller than the width dimension of one end part side (arrow B1 direction) opposite to the end part side. The second buffer region 48b has a substantially trapezoidal shape, and the width dimension increases continuously in the direction of the arrow B1.

  The second buffer area 48b is set in a deeper groove than the first buffer area 48a. An intermediate depth buffer region 48bm that is shallower in the stacking direction than the second buffer region 48b and deeper in the stacking direction than the first buffer region 48a is provided on the end side in the arrow B1 direction of the second buffer region 48b. . The intermediate depth buffer region 48bm is configured similarly to the intermediate depth buffer region 46bm.

  The oxidant gas outlet communication hole 20b is disposed from the center region in the width direction (arrow B direction) intersecting the flow direction (arrow C direction) of the oxidant gas flow path 26 toward the other side (arrow B2 direction). . The intermediate depth buffer region 48bm is located on one side opposite to the other side of the second buffer region 48b on the extension of the bulging guide portion 50mid2 connected to the central region in the width direction of the oxidant gas flow channel 26. It is provided between the ends.

  As shown in FIG. 1, the surface 42b of the resin frame member 42 on which the anode electrode 40 is provided has a plurality of inlet side connection grooves 54a whose one ends communicate with the fuel gas inlet communication hole 22a, and a fuel gas outlet communication hole 22b. A plurality of outlet side connection grooves 54b whose one ends communicate with each other are provided. The other end of the inlet side connecting groove 54 a communicates with the inlet buffer portion 56, while the other end of the outlet side connecting groove 54 b communicates with the outlet buffer portion 58.

  Each inlet-side connecting groove 54a is set to have a uniform length and a uniform width, and the same pressure loss. Similarly, each outlet-side connecting groove 54b is set to have a uniform length and a uniform width, and the same pressure loss.

  The inlet buffer part 56 communicates the fuel gas inlet communication hole 22a and the fuel gas flow path 32, and the outlet buffer part 58 communicates the fuel gas flow path 32 and the fuel gas outlet communication hole 22b.

  The inlet buffer portion 56 has a substantially triangular shape, and includes a first buffer region 56a adjacent to the fuel gas flow path 32 and a second buffer region 56b adjacent to the fuel gas inlet communication hole 22a. The first buffer region 56a is provided with a plurality of bulge guide portions 60 that continuously connect the fuel gas flow path 32 and the second buffer region 56b.

  Each bulge guide part 60 has a thin plate shape, and is arranged substantially evenly along the width direction (arrow B direction) of the fuel gas flow path 32 in parallel with each other. As shown in FIG. 6, the first buffer region 56a has a depth D4 in the stacking direction (arrow A direction) from the surface 42b (depth from the tip to the bottom of the bulging guide portion 60).

  As shown in FIG. 1, the second buffer region 56b is parallel to the inner end face of the fuel gas inlet communication hole 22a, and is formed long in the arrangement direction of the inlet side connection grooves 54a. The second buffer region 56b has a width dimension on one end side of the electrolyte membrane / electrode structure 18 (end side where the fuel gas inlet communication hole 22a is provided) (in the direction of arrow B2). It is set to a dimension smaller than the width dimension on the other end side (arrow B1 direction) opposite to the part side. The second buffer region 56b has a substantially trapezoidal shape, and the width dimension increases continuously in the direction of the arrow B1.

  As shown in FIG. 6, the second buffer region 56b has a depth D5 in the stacking direction (arrow A direction) from the surface 42b. The depth D5 of the second buffer region 56b is larger than the depth D4 of the first buffer region 56a, that is, a deep groove is set (D5> D4). An embossed portion 62 is provided in the second buffer area 56b.

  An intermediate depth buffer region 56bm that is shallower in the stacking direction than the second buffer region 56b and deeper in the stacking direction than the first buffer region 56a is provided on the end side in the arrow B2 direction of the second buffer region 56b. . The depth D6 of the intermediate depth buffer region 56bm has a relationship of D4 <D6 <D5.

  The intermediate depth buffer region 56bm is provided at an intermediate position between the bottom portion of the second buffer region 56b and the bottom portion of the bulging guide portion 60. The distance t3 between the bottom of the second buffer area 56b and the bottom of the intermediate depth buffer area 56bm, and the distance t4 between the bottom of the intermediate depth buffer area 56bm and the bottom of the first buffer area 56a have a relationship of t3 = t4. Set to

  As shown in FIG. 1, the fuel gas inlet communication hole 22a extends from the central region in the width direction (arrow B direction) intersecting the flow direction (arrow C direction) of the fuel gas flow path 32 to the other side (arrow B2 direction). Arranged closer. The intermediate depth buffer region 56bm is provided between the extension of the bulging guide portion 60mid1 connected to the central region in the width direction of the fuel gas passage 32 and the other end portion of the second buffer region 56b. It is done.

  The outlet buffer portion 58 has a substantially triangular shape, and includes a first buffer region 58a adjacent to the fuel gas flow path 32 and a second buffer region 58b adjacent to the fuel gas outlet communication hole 22b. The first buffer region 58a is provided with a plurality of bulge guide portions 60 that continuously connect the fuel gas flow path 32 and the second buffer region 58b.

  The second buffer region 58b is parallel to the inner end face of the fuel gas outlet communication hole 22b and is formed long in the arrangement direction of the outlet side connection grooves 54b. The second buffer region 58b has a width dimension on the other end side of the electrolyte membrane / electrode structure 18 (on the end side where the fuel gas outlet communication hole 22b is provided) (in the direction of the arrow B1). It is set to a dimension smaller than the width dimension on the one end side (arrow B2 direction) opposite to the part side. The second buffer region 58b has a substantially trapezoidal shape, and the width dimension increases continuously in the direction of the arrow B2.

  The second buffer area 58b is set in a deeper groove than the first buffer area 58a. An intermediate depth buffer region 58bm that is shallower in the stacking direction than the second buffer region 58b and deeper in the stacking direction than the first buffer region 58a is provided on the end side in the arrow B2 direction of the second buffer region 58b. . The intermediate depth buffer area 58bm is configured in the same manner as the intermediate depth buffer area 56bm.

  The fuel gas outlet communication hole 22b is disposed from the center region in the width direction (arrow B direction) intersecting the flow direction (arrow C direction) of the fuel gas flow path 32 to the other side (arrow B1 direction). The intermediate depth buffer region 58bm is an end on one side opposite to the other side of the second buffer region 58b on the extension of the bulging guide portion 60mid2 connected to the central region in the width direction of the fuel gas channel 32. Between the two parts.

  A seal member 64 is formed on both surfaces 42a and 42b of the resin frame member 42 by, for example, integral molding by injection molding or by joining separate parts. As the sealing member 64, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or other sealing material, cushioning material, packing material or the like is used. The sealing member which has is used.

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

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

  For this reason, as shown in FIG. 3, the oxidant gas passes through the inlet side connecting groove 44a formed in the resin frame member 42 of the electrolyte membrane / electrode structure 18 through the oxidant gas inlet communication hole 20a, and the inlet buffer portion. 46. Further, the oxidant gas is supplied from the inlet buffer unit 46 to the oxidant gas flow path 26 of the first separator 14 (see FIG. 1). The oxidant gas moves in the direction of arrow C (gravity direction) along the oxidant gas flow path 26 and is supplied to the cathode electrode 38 of the electrolyte membrane / electrode structure 18.

  On the other hand, as shown in FIG. 1, the fuel gas is introduced into the inlet buffer 56 from the fuel gas inlet communication hole 22 a through the inlet side connection groove 54 a formed in the resin frame member 42 of the electrolyte membrane / electrode structure 18. Is done. Further, the fuel gas moves in the gravity direction (arrow C direction) along the fuel gas flow path 32 of the second separator 16 from the inlet buffer 56 and is supplied to the anode electrode 40 of the electrolyte membrane / electrode structure 18. .

  Therefore, in the electrolyte membrane / electrode structure 18, the oxidant gas supplied to the cathode electrode 38 and the fuel gas supplied to the anode electrode 40 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas supplied to and consumed by the cathode electrode 38 of the electrolyte membrane / electrode structure 18 is discharged from the outlet buffer portion 48 to the oxidant gas outlet communication hole 20b through the outlet side connection groove 44b ( (See FIG. 3). Further, as shown in FIG. 1, the fuel gas supplied to and consumed by the anode electrode 40 of the electrolyte membrane / electrode structure 18 passes through the outlet side connecting groove 54b from the outlet buffer 58 and the fuel gas outlet communication hole 22b. To be discharged.

  On the other hand, after the cooling medium supplied to the cooling medium inlet communication hole 24a is introduced into the cooling medium flow path 28 formed between the first separator 14 and the second separator 16, as shown in FIG. Circulate in the direction of arrow B. The cooling medium cools the electrolyte membrane / electrode structure 18 and then is discharged to the cooling medium outlet communication hole 24b.

  In this case, in the first embodiment, as shown in FIG. 4, the surface 42a of the resin frame member 42 is provided with an inlet buffer portion 46 adjacent to the oxidant gas inlet communication hole 20a. The inlet buffer unit 46 includes a first buffer region 46a adjacent to the oxidant gas flow path 26 and a second buffer region 46b adjacent to the oxidant gas inlet communication hole 20a. As shown in FIG. 5, the depth D2 of the second buffer region 46b is larger than the depth D1 of the first buffer region 46a, that is, a deep groove is set (D2> D1).

  Therefore, the oxidant gas supplied from the oxidant gas inlet communication hole 20a to the inlet buffer 46 is well distributed from the second buffer region 46b to the first buffer region 46a, and then supplied to the oxidant gas flow channel 26. Is done.

  In addition, the second buffer region 46b is provided with an intermediate depth buffer region 46bm that is shallower in the stacking direction than the second buffer region 46b and deeper in the stacking direction than the first buffer region 46a. Thereby, in the second buffer region 46b, the distribution of the oxidant gas is reduced by the intermediate depth buffer region 46bm.

  Therefore, by setting the position and range of the intermediate depth buffer region 46bm, it is possible to adjust the increase / decrease in the distribution of the oxidant gas. In the first embodiment, as shown in FIG. 4, the intermediate depth buffer region 46bm is on the oxidant gas inlet communication hole 20a side, that is, on the one side in the width direction of the oxidant gas flow channel 26 (arrow B1 direction). It is provided close by.

  Therefore, one side in the width direction in which the oxidant gas easily flows from the oxidant gas inlet communication hole 20a is configured as a shallower groove than the other side in the width direction in which the oxidant gas does not easily flow. As a result, pressure loss increases on one side in the width direction of the oxidant gas inlet communication hole 20a so that the oxidant gas does not flow more easily than the other side in the width direction, and the oxidant gas flows evenly throughout the width direction. Can be made.

  Therefore, with a simple configuration, the oxidant gas can be uniformly and reliably supplied from the oxidant gas inlet communication hole 20a to the entire oxidant gas flow path 26 via the inlet buffer unit 46, and good power generation performance can be obtained. The effect that it becomes possible to hold | maintain is acquired.

  On the other hand, as shown in FIG. 3, an outlet buffer portion 48 is provided on the surface 42a of the resin frame member 42 adjacent to the oxidant gas outlet communication hole 20b. The outlet buffer section 48 has a first buffer region 48a adjacent to the oxidant gas flow path 26 and a second buffer region 48b adjacent to the oxidant gas outlet communication hole 20b. The second buffer area 48b is set in a deeper groove than the first buffer area 48a.

  The second buffer region 48b is provided with an intermediate depth buffer region 48bm that is shallower in the stacking direction than the second buffer region 48b and deeper in the stacking direction than the first buffer region 48a. As a result, the oxidant gas flows smoothly and uniformly from the oxidant gas flow path 26 through the first buffer region 48a to the second buffer region 48b, and then is discharged to the oxidant gas outlet communication hole 20b. For this reason, in the oxidant gas flow path 26, it becomes possible to make the distribution of the oxidant gas uniform throughout the power generation region.

  As shown in FIGS. 1 and 6, an inlet buffer portion 56 is provided on the surface 42b of the resin frame member 42 adjacent to the fuel gas inlet communication hole 22a. The inlet buffer unit 56 includes a first buffer region 56a adjacent to the fuel gas flow path 32 and a second buffer region 56b adjacent to the fuel gas inlet communication hole 22a. The depth D5 of the second buffer region 56b is larger than the depth D4 of the first buffer region 56a, that is, a deep groove is set (D5> D4).

  Therefore, the fuel gas supplied from the fuel gas inlet communication hole 22a to the inlet buffer portion 56 is well distributed from the second buffer region 56b to the first buffer region 56a, and then supplied to the fuel gas passage 32.

  In addition, the second buffer region 56b is provided with an intermediate depth buffer region 56bm that is shallower in the stacking direction than the second buffer region 56b and deeper in the stacking direction than the first buffer region 56a. Thereby, in the second buffer region 56b, the distribution of the fuel gas is reduced by the intermediate depth buffer region 56bm. Therefore, by setting the position of the intermediate depth buffer region 56bm, it is possible to adjust the increase / decrease in the distribution of the fuel gas.

  Therefore, the fuel gas can be uniformly and reliably supplied to the entire fuel gas flow path 32 from the fuel gas inlet communication hole 22a via the inlet buffer portion 56 with a simple configuration, and good power generation performance can be maintained. The effect that it becomes possible is obtained.

  On the other hand, on the surface 42b of the resin frame member 42, an outlet buffer portion 58 is provided adjacent to the fuel gas outlet communication hole 22b. The outlet buffer unit 58 is configured in the same manner as the inlet buffer unit 56 described above. As a result, the fuel gas flows smoothly and uniformly from the fuel gas flow path 32 through the first buffer region 58a to the second buffer region 58b, and then is discharged into the fuel gas outlet communication hole 22b. For this reason, in the fuel gas channel 32, it becomes possible to make the distribution of the fuel gas uniform over the entire power generation region.

  Accordingly, the oxidant gas and the fuel gas are uniformly and reliably supplied to the entire oxidant gas flow path 26 formed in the first separator 14 and the entire fuel gas flow path 32 formed in the second separator 16. be able to. Thereby, the fuel cell 10 has an effect that it is possible to maintain a good power generation performance with a simple configuration.

  The resin frame member 42 may be provided with only the oxidant gas inlet buffer portion 46 and the outlet buffer portion 48, or may be provided with only the fuel gas inlet buffer portion 56 and the outlet buffer portion 58. Good. Further, the outlet buffer sections 48 and 58 do not have to be provided with intermediate depth buffer areas 48bm and 58bm. The same applies to the second and subsequent embodiments described below.

  FIG. 7 is an exploded schematic perspective view of the power generation cell 72 constituting the fuel cell 70 according to the second embodiment of the present invention. 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.

  The power generation cell 72 sandwiches an electrolyte membrane / electrode structure (MEA) 78 between the first separator 74 and the second separator 76. The electrolyte membrane / electrode structure 78 includes a solid polymer electrolyte membrane 36a, and a cathode electrode 38a and an anode electrode 40a that sandwich the solid polymer electrolyte membrane 36a. The solid polymer electrolyte membrane 36a has the same planar dimensions (outer dimensions) as the first separator 74 and the second separator 76, and the cathode electrode 38a and the anode electrode 40a are smaller planes than the solid polymer electrolyte membrane 36a. Have dimensions.

  The first separator 74 and the second separator 76 are made of, for example, a carbon separator. In addition, the 1st separator 74 and the 2nd separator 76 may use a metal plate corresponding to an electric power generation area | region, and may comprise a resin frame member (frame part) on the outer periphery of the said metal plate.

  As shown in FIG. 8, the oxidant gas flow path 26 is formed on the surface 74 a of the first separator 74 facing the electrolyte membrane / electrode structure 78. In order to connect the oxidizing gas inlet communication hole 20a and the oxidizing gas channel 26 to the surface 74a, an inlet side connecting groove 44a and an inlet buffer portion 46 are provided. The surface 74a is provided with an outlet side connection groove 44b and an outlet buffer portion 48 in order to connect the oxidant gas outlet communication hole 20b and the oxidant gas flow path 26.

  As shown in FIG. 7, the fuel gas flow path 32 is formed on the surface 76 a of the second separator 76 facing the electrolyte membrane / electrode structure 78. In order to connect the fuel gas inlet communication hole 22a and the fuel gas flow path 32 to the surface 76a, an inlet side connection groove 54a and an inlet buffer portion 56 are provided. The surface 76 a is provided with an outlet side connection groove 54 b and an outlet buffer portion 58 in order to connect the fuel gas outlet communication hole 22 b and the fuel gas flow path 32.

  A cooling medium flow path 28 is formed between the surface 74 b of the first separator 74 and the surface 76 b of the second separator 76. The cooling medium flow path 28 may be provided on at least one of the surface 74b or the surface 76b.

  In the second embodiment configured as described above, as shown in FIG. 8, an inlet buffer portion 46 and an outlet buffer portion 48 are provided on the surface 74 a of the first separator 74. On the other hand, as shown in FIG. 7, an inlet buffer portion 56 and an outlet buffer portion 58 are provided on the surface 76 a of the second separator 76. For this reason, it is possible to make the distribution of the oxidant gas and the fuel gas uniform in the entire power generation region with a simple configuration, and to maintain good power generation performance. Similar effects can be obtained.

  FIG. 9 is a partial explanatory view of an electrolyte membrane / electrode structure 80 constituting a fuel cell according to the third embodiment of the present invention.

  The resin frame member 82 constituting the electrolyte membrane / electrode structure 80 is provided with an inlet buffer portion 84. Although not shown, the resin frame member 82 includes an oxidant gas side outlet buffer (corresponding to the outlet buffer 48), a fuel gas side inlet buffer (corresponding to the inlet buffer 56), and an outlet buffer ( Corresponding to the outlet buffer 58). These structures are the same as those of the inlet buffer unit 84. Further, the present invention can be similarly applied to the first separator 74 and the second separator 76 of the second embodiment.

  The inlet buffer unit 84 includes a first buffer region 84a adjacent to the oxidant gas flow path 26 and a second buffer region 84b adjacent to the oxidant gas inlet communication hole 20a. As shown in FIG. 10, in the second buffer region 84b, one end side in the width direction of the oxidant gas flow path 26 (arrow B1 direction) to the other end side in the width direction (arrow B2 direction). An inclined portion 86 whose depth in the stacking direction continuously changes is provided. In the second buffer region 84b, the depth D7 at the end in the arrow B1 direction is set to be shallower than the depth D8 at the end in the arrow B2 direction (D7 <D8).

  In the third embodiment configured as described above, the same effects as those in the first embodiment can be obtained, such as uniform distribution of the oxidant gas in the entire power generation region of the oxidant gas flow path 26. . In the third embodiment, the inclined portion 86 is provided in the second buffer region 84b. Instead, for example, a multistage structure in which the depth changes in two steps (or more) is provided. It may be adopted.

DESCRIPTION OF SYMBOLS 10,70 ... Fuel cell 12, 72 ... Power generation cell 14, 16, 74, 76 ... Separator 18, 78, 80 ... Electrolyte membrane electrode assembly 20a ... Oxidant gas inlet communication hole 20b ... Oxidant gas outlet communication hole 22a ... fuel gas inlet communication hole 22b ... fuel gas outlet communication hole 24a ... cooling medium inlet communication hole 24b ... cooling medium outlet communication hole 26 ... oxidant gas flow path 28 ... cooling medium flow path 32 ... fuel gas flow path 36 ... solid height Molecular electrolyte membrane 38 ... Cathode electrode 40 ... Anode electrode 42, 82 ... Resin frame member 44a, 54a ... Inlet side connecting groove 44b, 54b ... Outlet side connecting groove 46, 56, 84 ... Inlet buffer part 46a, 46b, 48a, 48b 56a, 56b, 58a, 58b, 84a, 84b... Buffer areas 46bm, 56bm, 58bm... Intermediate depth buffer areas 48, 58. Fa part 50, 60 ... bulge guide part 86 ... inclined part

Claims (6)

An electrolyte membrane / electrode structure provided with electrodes on both sides of the electrolyte membrane is sandwiched between separators, and a reaction gas channel for supplying a reaction gas along the electrode surface of the electrolyte membrane / electrode structure, and the reaction gas A fuel cell in which a reaction gas communication hole that flows in the stacking direction of the separator is formed,
A buffer unit is provided for communicating the reaction gas communication hole and the reaction gas channel;
The buffer section includes a first buffer region adjacent to the reaction gas flow path,
A second buffer region adjacent to the reaction gas communication hole and deeper in the stacking direction than the first buffer region;
Have
The reactive gas communication hole is disposed closer to one side from the center in the width direction intersecting the flow direction of the reactive gas flow path,
The second buffer region has a depth in the stacking direction that is farther from the reaction gas communication hole disposed on one side in the width direction than in an end near the reaction gas communication hole in the width direction. It is formed so that it may become. The fuel cell characterized by the above-mentioned.   2. The fuel cell according to claim 1, wherein the second buffer region includes a second buffer region main body, a middle portion shallower in the stacking direction than the second buffer region main body and deeper in the stacking direction than the first buffer region. And a depth buffer region. 3. The fuel cell according to claim 2, wherein the first buffer region is provided with a plurality of bulge guide portions that continuously connect the reaction gas flow path and the second buffer region,
The fuel cell according to claim 1, wherein a bottom portion of the intermediate depth buffer region is provided at an intermediate position between a bottom portion of the second buffer region main body and a bottom portion of the bulging guide portion. The fuel cell according to claim 3, wherein
The intermediate depth buffer region is formed on the extension of the bulge guide portion located on the most one side of the bulge guide portions connected to the other side of the center in the width direction of the reaction gas flow path and the second. A fuel cell provided between the buffer region body and the one end of the buffer region body. A fuel cell according to claim 4, wherein the reaction gas communication hole is reaction gas supply passage,
Inlet buffer that communicates the front Symbol reactant gas supply passage and the reactant gas flow field, said intermediate depth buffer region is provided on the one side of the second buffer area body,
The fuel cell has a reaction gas outlet communication hole that is disposed closer to the other side from the center in the width direction and that allows the reaction gas to flow in the stacking direction of the separator, and the reaction gas outlet communication hole and the reaction An outlet buffer unit communicating with the gas flow path is provided,
The outlet buffer section includes a first outlet buffer region adjacent to the reaction gas flow path,
A second outlet buffer region adjacent to the reaction gas outlet communication hole and deeper in the stacking direction than the first outlet buffer region;
Have
The second outlet buffer region includes a second outlet buffer region body, and an intermediate depth outlet buffer region that is shallower in the stacking direction than the second outlet buffer region body and deeper in the stacking direction than the first outlet buffer region. And provided,
Before Kide port buffer unit, the fuel cell, characterized in that said intermediate depth outlet buffer area is provided on the one side of the second outlet buffer area body.   2. The fuel cell according to claim 1, wherein the second buffer region has an inclination in which a depth in the stacking direction continuously changes from one side in the width direction to the other side in the width direction of the reaction gas channel. A fuel cell, characterized in that a part is provided.

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