JP4639744B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell gas flow path forming member and a fuel cell.

  A fuel cell is generally formed as a stack of single cells. A single cell is formed by an MEA (Membrane Electrode Assembly) composed of an electrolyte layer with a catalyst layer formed on the surface and a gas-impermeable member having conductivity, and forms a gas flow path in the single cell between the MEA. And a separator. In such a fuel cell, a member for ensuring a gas flow in the single cell is usually disposed between the MEA and the separator. As an example of providing a member for ensuring gas flow in such a single cell, a configuration using a member formed by processing a metal plate into a shape having a large number of fins is known (for example, Patent Documents). 1). Since the metal member is superior in strength to other types of conductive members such as carbon members, it is less likely to be deformed even when a pressing force is applied in the stacking direction of the single cells inside the fuel cell. Thus, a space serving as a gas flow path can be secured stably. Furthermore, the metal member has an advantage that it can be easily processed.

JP 2003-282098 A JP 2004-87318 A JP 2002-367621 A JP 2003-173789 A

  However, when a member provided with a large number of fins by processing a metal plate is used as a member for forming a gas flow path in a single cell, the gas diffusibility is at the contact portion between the end of the fin and the MEA. May be insufficient. That is, there is a possibility that the gas is not sufficiently supplied to the contact portion of the MEA catalyst layer with the fin end. In such a case, it is difficult for the electrochemical reaction to proceed sufficiently in the contact portion, which may cause a reduction in power generation efficiency of the entire battery.

  Here, in order to reduce the region where the gas supply is insufficient in the catalyst layer, a configuration in which the end portion of the fin contacting the MEA is made smaller is also conceivable. However, when the contact portion is made small in this way, the current collection between the member forming the flow path and the MEA becomes insufficient, and the power generation efficiency of the fuel cell may be suppressed.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to improve power generation performance when forming a gas flow path forming member using a metal member.

In order to achieve the above object, the first fuel cell gas flow path forming member of the present invention is used by laminating together with an electrolyte layer having a catalyst layer on the surface, and is used for an electrochemical reaction. A fuel cell gas flow path forming member for forming
When a predetermined adjacent member having an uneven shape and sandwiching the fuel cell gas flow path forming member from both sides is disposed, the front and back surfaces of the fuel cell gas flow path forming member are disposed between the adjacent members. Uneven portions forming a communicating space;
At least on the surface side facing the electrolyte layer when the fuel cell gas flow path forming member is disposed in the fuel cell, the uneven portion is formed in a region to be a contact portion that contacts the adjacent member, Pores through which gas can circulate in the thickness direction of the irregularities;
With
The gist of the fuel cell gas flow path forming member is formed of a metal member.

  According to the first fuel cell gas flow path forming member of the present invention configured as described above, the surface having the pores when the fuel cell is assembled using the fuel cell gas flow path forming member. By disposing on the catalyst layer side, the gas supply / discharge efficiency in the catalyst layer can be improved, and the performance of the fuel cell can be improved. Further, by disposing the first fuel cell gas flow path forming member of the present invention so that the surface having the pores is on the catalyst layer side, drainage performance in the catalyst layer is improved, and the fuel cell Performance can be improved.

In the first fuel cell gas flow path forming member of the present invention,
The concavo-convex shape is such that a total area of a region that becomes a contact portion between the concavo-convex portion and the adjacent member on the surface side facing the electrolyte layer is equal to a contact portion between the concavo-convex portion and the adjacent member on the other surface side. The shape may be larger than the total area of the region to be formed.

  With this configuration, when the fuel cell is assembled using the fuel cell gas flow path forming member, the side having the larger total area of the region to be the contact portion is disposed on the catalyst layer side. In addition, the current collecting property in the fuel cell can be improved. Furthermore, by disposing the fuel cell gas flow path forming member in the above-described direction, the pressure applied to the electrolyte layer can be dispersed throughout the electrolyte layer, so that a strong pressure is locally applied to the electrolyte layer. In the fuel cell, the durability of the electrolyte layer can be improved.

The first fuel cell gas flow path forming member of the present invention comprises:
Forming the concave-convex shape by subjecting a metal plate-like member to shearing and subjecting the vicinity of the sheared portion subjected to the shearing processing to elongation and / or bending of the plate-like member. It is also good to have done.

  With such a configuration, it becomes possible to produce the fuel cell gas flow path forming member by simple press working, and the manufacturing process of the fuel cell gas flow path forming member can be simplified.

The second fuel cell gas flow path forming member of the present invention is used by laminating with an electrolyte layer having a catalyst layer on the surface, and forms a flow path for a gas to be subjected to an electrochemical reaction. A road forming member,
When a predetermined adjacent member having an uneven shape and sandwiching the fuel cell gas flow path forming member from both sides is disposed, the front and back surfaces of the fuel cell gas flow path forming member are disposed between the adjacent members. It has a concavo-convex part that forms a communicating space,
The gist of the fuel cell gas flow path forming member is formed of a metal porous body.

  According to the second fuel cell gas flow path forming member of the present invention configured as described above, by assembling a fuel cell using the fuel cell gas flow path forming member, the gas supply in the catalyst layer is performed. The exhaust efficiency can be improved and the performance of the fuel cell can be improved. Moreover, the drainage property in a catalyst layer can be improved and the performance of a fuel cell can be improved.

In the second fuel cell gas flow path forming member of the present invention,
The concavo-convex shape has a total area of a region that becomes a contact portion between the concavo-convex portion and the adjacent member on the surface facing the electrolyte when the fuel cell gas flow path forming member is disposed in the fuel cell. The shape may be larger than the total area of the region serving as the contact portion between the uneven portion and the adjacent member on the other surface side.

  With this configuration, when the fuel cell is assembled using the fuel cell gas flow path forming member, the side having the larger total area of the region to be the contact portion is disposed on the catalyst layer side. In addition, the current collecting property in the fuel cell can be improved. Furthermore, since the pressure applied to the electrolyte layer can be dispersed throughout the electrolyte layer, a strong pressure is not locally applied to the electrolyte layer, and the durability of the electrolyte layer in the fuel cell can be improved.

In the first or second fuel cell gas flow path forming member of the present invention,
The concavo-convex shape is a shape in which a plurality of rows composed of a plurality of convex portions arranged in a row are arranged so that the rows are parallel to each other, and between adjacent rows, a direction perpendicular to the rows The protrusions may be arranged so that the position of the protrusions shows a predetermined deviation.

  With such a configuration, it is possible to improve the gas supply efficiency to the catalyst layer by stirring the gas in the gas flow path formed in the fuel cell by the fuel cell gas flow path forming member. In addition, the uniformity of gas distribution can be improved in the gas flow path formed in the single cell by the fuel cell gas flow path forming member.

The first fuel cell gas flow path forming member manufacturing method according to the present invention is used by laminating together with an electrolyte layer having a catalyst layer on the surface, and forms a flow path for a gas to be subjected to an electrochemical reaction. A method for producing a gas flow path forming member,
(A) preparing a metal plate member;
(B) forming a plurality of pores by punching the plate member in a thickness direction at a predetermined position of the plate member;
(C) forming a plurality of cut portions made of two cuts penetrating the plate member at a predetermined position of the plate member;
(D) Substrate part which is other area | regions of the said plate-shaped member, and has the said pore by performing a shaping | molding process with respect to the area | region between two notches of each said notch part formed in the said plate-shaped member And a step of forming a convex portion having a predetermined height.

The second fuel cell gas flow path forming member manufacturing method of the present invention is used by laminating together with an electrolyte layer having a catalyst layer on the surface, and forms a flow path for a gas to be subjected to an electrochemical reaction. A method for producing a gas flow path forming member,
(A) preparing a porous metal plate-like member;
(B) forming a plurality of cuts penetrating the plate member at a predetermined position of the plate member;
(C) Forming the concavo-convex portion having a concavo-convex shape that is communicated over both the front and back surfaces of the plate-like member through the cuts, by forming the region where the plurality of cuts are formed in the plate-like member. The gist is to provide a process.

  According to the first and second fuel cell gas flow path forming members of the present invention configured as described above, the fuel cell gas flow path forming member can be produced by simple press working. Thus, the manufacturing process of the fuel cell gas flow path forming member can be simplified.

  The present invention can be realized in various forms other than those described above. For example, the present invention can be realized in the form of a fuel cell including a fuel cell gas flow path forming member, a method of manufacturing a fuel cell gas flow path forming member, and the like. Is possible.

Next, embodiments of the present invention will be described in the following order based on examples.
A. Fuel cell configuration:
B. Structure and operation of gas flow path forming member:
C. Second embodiment:
D. Variations:

A. Fuel cell configuration:
The fuel cell of the first embodiment of the present invention is a polymer electrolyte fuel cell and has a stack structure in which a plurality of single cells are stacked. FIG. 1 is a schematic cross-sectional view showing an outline of the configuration of a single cell 20 constituting the fuel cell of the first embodiment. The unit cell 20 includes an electrolyte layer 21 having a catalyst layer (not shown) on the surface, gas diffusion layers 22 and 23 that sandwich the electrolyte layer 21 from both sides to form a sandwich structure, and the sandwich structure further from both sides. Gas flow path forming members 25 and 26 to be sandwiched, and separators 27 and 28 disposed outside the gas flow path forming members 25 and 26 are provided.

  The electrolyte layer 21 is a proton conductive ion exchange membrane formed of a solid polymer material such as a fluorine resin, and exhibits good electrical conductivity in a wet state. In this example, a Nafion membrane (manufactured by DuPont) was used. The catalyst layer formed on the electrolyte layer 21 includes a catalyst that promotes an electrochemical reaction, such as platinum or an alloy made of platinum and other metals. In order to form the catalyst layer, for example, carbon powder carrying platinum or an alloy made of platinum and another metal is prepared, and the carbon powder carrying the catalyst is dispersed in an appropriate organic solvent, and an electrolyte solution (for example, Aldrich) is formed. A paste may be prepared by adding an appropriate amount of Chemical, Nafion Solution). By applying this paste onto the electrolyte layer 21 by a method such as screen printing, a catalyst layer can be formed. Alternatively, a sheet containing a carbon powder carrying the catalyst is formed into a sheet, and a sheet is formed on the electrolyte layer 21 by pressing the sheet, or the paste is used as a gas diffusion layer 22, It is good also as applying to 23 side.

  The gas diffusion layers 22 and 23 are made of a member having gas permeability and electronic conductivity, and are formed of, for example, a metal member such as foam metal or metal mesh, or a carbon member such as carbon cloth or carbon paper. can do. Such gas diffusion layers 22 and 23 diffuse the gas used for the electrochemical reaction and collect current with the catalyst layer.

  The gas flow path forming members 25 and 26 are disposed between the gas diffusion layer and the separator, and form a space serving as a gas flow path between them. The gas flow path forming member 25 disposed between the gas diffusion layer 22 and the separator 27 forms an in-single cell oxidizing gas flow path through which an oxidizing gas containing oxygen passes. Further, the gas flow path forming member 26 disposed between the gas diffusion layer 23 and the separator 28 forms a fuel gas flow path in a single cell through which a fuel gas containing hydrogen passes. Here, in this embodiment, the gas flow path forming members 25 and 26 are made of titanium. Titanium is a metal with excellent corrosion resistance, and is desirable as a constituent material of a member that forms a fuel gas channel in a single cell that provides a strong reducing atmosphere and an oxidizing gas channel in a single cell that provides a strong oxidizing atmosphere. If the durability is acceptable, the gas flow path forming members 25 and 26 may be formed of other types of metals such as stainless steel. Alternatively, the gas flow path forming members 25 and 26 may be formed by forming a metal plate into a predetermined shape and then providing a corrosion-resistant layer such as a noble metal layer on the surface. The structure of the gas flow path forming members 25 and 26 corresponds to the main part of the present invention, and will be described in detail later.

  The separators 27 and 28 are gas-impermeable members formed of a material having electron conductivity, and can be formed of, for example, a metal member such as stainless steel or a carbon member. The separators 27 and 28 of the present embodiment are formed in a thin plate shape, and the surfaces in contact with the gas flow path forming members 25 and 26 are flat surfaces with no unevenness.

In addition, a sealing member such as a gasket is disposed on the outer peripheral portion of the single cell 20 in order to ensure gas sealing performance in the single-cell fuel gas flow path and the single-cell oxidizing gas flow path. In addition, a plurality of gas manifolds (not shown) are provided on the outer peripheral portion of the single cell 20 in parallel with the stacking direction of the single cells 20 and through which fuel gas or oxidizing gas flows. The fuel gas flowing through the fuel gas supply manifold among the plurality of gas manifolds is distributed to each single cell 20 and is subjected to an electrochemical reaction, and the fuel gas flow path in each single cell (the gas flow path forming member 26 and the gas). It passes through the diffusion layer 23) and then collects in the fuel gas discharge manifold. Similarly, the oxidant gas flowing through the oxidant gas supply manifold is distributed to each single cell 20 and is supplied to the electrochemical cell in each single cell while being subjected to an electrochemical reaction (in the gas channel forming member 25 and the gas diffusion layer 22). And then collect in the oxidizing gas discharge manifold. In FIG. 1, the fuel gas (H ₂ ) in the single-cell fuel gas flow path and the oxidizing gas (O ₂ ) in the single-cell oxidizing gas flow path are shown to flow in parallel. Depending on the arrangement of the gas manifold, the flow may flow in different directions such as facing and orthogonal, in addition to the above-described parallel.

  As the fuel gas supplied to the fuel cell, a hydrogen-rich gas obtained by reforming a hydrocarbon-based fuel may be used, or a high-purity hydrogen gas may be used. For example, air can be used as the oxidizing gas supplied to the fuel cell.

  Although illustration is omitted, in order to adjust the internal temperature of the stack structure, a refrigerant flow path through which the refrigerant passes may be provided between the single cells or every time a predetermined number of single cells are stacked. good. For example, the refrigerant flow path can be provided between the separators 27 included in one unit cell and the separators 28 included in the other unit cell between adjacent unit cells.

B. Structure and operation of gas flow path forming member:
FIG. 2 is a plan view showing an outline of the configuration of the gas flow path forming member 25, and FIG. 3 is a cross-sectional view taken along the line 3-3 in FIG. The gas flow path forming member 26 has the same structure as that of the gas flow path forming member 25, and only the direction in which the gas flow path forming member 26 is disposed in the single cell 20 is different (opposing each other). The flow path forming member 25 will be described.

  As shown in FIG. 2, the gas flow path forming member 25 includes a flat plate-like substrate portion 30 and a plurality of convex portions 32 provided so as to protrude from the substrate portion 30. The substrate part 30 is provided with a large number of pores 34 penetrating the substrate part 30 in the thickness direction in a regular arrangement. As shown in FIG. 2, the concavo-convex shape formed by the substrate portion 30 and the convex portion 32 is a row in which a plurality of convex portions 32 are arranged in one direction (X direction in FIG. 2) at equal intervals (an example in FIG. 2). Is shown in a row L), and a plurality of such rows are arranged in parallel to each other. Here, between adjacent rows, a plurality of rows are arranged so that the position of the convex portion 32 shows a predetermined shift with respect to a direction perpendicular to the row (Y direction in FIG. 2). The convex portion 32 has a hollow convex structure that allows gas to flow therethrough. FIG. 4 is an enlarged perspective view showing the state of the region R shown in FIG.

  As shown in FIG. 4, the convex part 32 has a substantially rectangular parallelepiped shape as a whole. Of the four side surfaces in the substantially rectangular parallelepiped shape, the side wall 32w constituting a pair of opposing side surfaces and the upper surface 32t of the substantially rectangular parallelepiped are formed continuously and provided integrally with the substrate unit 30. It has been. Moreover, the other side surface which opposes in the said substantially rectangular parallelepiped shape is the opening part 32p. Note that the lower surface of the substantially rectangular parallelepiped is an opening 32 e in the substrate portion 30. Inside the single cell 20, the gas flow path forming member 25 is disposed in such a direction that the substrate portion 30 contacts the gas diffusion layer 22 and the upper surface 32 t of each convex portion 32 contacts the separator 27.

  The gas flow path forming member 25 of this embodiment is manufactured by forming a single metal plate-like member into a predetermined uneven shape by a series of press processes. FIG. 5 is an explanatory view showing a manufacturing process of the gas flow path forming member 25.

  When manufacturing the gas flow path forming member 25, first, a metal plate-like member is prepared (step S100). In this embodiment, a substantially rectangular plate-like member made of titanium is prepared. The plate-like member can have a thickness of 0.1 mm to 0.2 mm, for example.

  Next, the pores 34 are formed at predetermined positions of the plate-like member by punching (step S110). A state in which the pores 34 are formed in the plate-like member is shown in FIG. As shown in FIG. 6, the pores 34 of the present embodiment are arranged vertically and horizontally in consideration of the position where the convex portion 32 is formed, that is, excluding the position where the convex portion 32 is formed. Provided. For example, the pores 34 may be substantially circular with a diameter of 1 mm or less.

  In addition to step S110, the notch 36 is formed in the plate-shaped member by shearing (linear cutting) (step S120). FIG. 7 shows a state in which the cut portions 36 are formed together with the pores 34 in the plate-like member. The cut portion 36 includes two cuts 37 that pass through the plate member and have a predetermined length and are substantially parallel to each other, and is provided at a position corresponding to a position where the convex portion 32 is to be formed. That is, when the convex part 32 is formed in the plate-like member, the notch 37 is formed at a position corresponding to a line segment forming one side of the opening part 32p, which is the two opposing sides of the opening part 32e. . The side in the opening 32p corresponding to this notch 37 is shown as side 32l in FIG.

  Then, the convex part 32 is formed by overhang forming (step S130), and the gas flow path forming member 25 is completed. That is, the convex portion 32 is formed by stretching between the two substantially parallel cuts 37 described above in the plate-like member by stretch forming.

  The gas flow path forming member 25 manufactured in this way forms an oxidizing gas flow path in the single cell in the fuel cell as described above, and the oxidizing gas is separated from the gas diffusion layer 22 by the gas flow path forming member 25. The gas diffused in the gas diffusion layer 22 while passing through the space formed between the separator 27 and supplied to the catalyst layer. Here, as a whole oxidant gas flow path in the single cell, the oxidant gas flows in a certain direction (see FIGS. 1 and 2), but in the actual oxidant gas flow path in the single cell, The gas flow direction is disturbed in various directions by the convex portion 32. More specifically, the oxidizing gas comes into contact with the side wall 32w of the convex portion 32 to change its direction, and a part thereof enters and exits the convex portion 32 through the opening 32p.

  When the fuel cell performs power generation, oxidation is performed between the oxidizing gas flow path in the single cell and the catalyst layer via the pores 34 and the openings 32 e provided in the substrate portion 30 and the gas diffusion layer 22. Gas is supplied and discharged. In addition, when the fuel cell generates power, water is generated on the cathode catalyst layer as the electrochemical reaction proceeds. In this embodiment, the gas diffusion layer 22 and the pores provided in the substrate portion 30 are generated. The generated water is discharged from the catalyst layer to the oxidizing gas flow path in the single cell through 34 and the opening 32e. Similarly, fuel gas is supplied to and discharged from the catalyst layer in the fuel gas flow path in the single cell.

  According to the fuel cell of the present embodiment configured as described above, since the pores 34 are provided in the substrate portion 30 of the gas flow path forming member, between the gas flow path in the single cell and the catalyst layer, In addition to the opening 32e formed when the convex portion 32 is provided, the gas can be further supplied and discharged through the pore 34. That is, even in the region covered with the substrate portion 30, the gas flow to the catalyst layer can be ensured through the pores 34. Therefore, the efficiency of supplying and discharging gas between the gas flow path in the single cell and the catalyst layer can be improved. Further, according to the fuel cell of the present embodiment, since the pores 34 are provided in the substrate part 30 of the gas flow path forming member, in addition to the opening part 32e formed when the convex part 32 is provided, the finer part 34 is further reduced. It is possible to discharge the generated water generated in the catalyst layer on the cathode side to the gas flow path side in the single cell through the hole 34. Therefore, the drainage efficiency of generated water can be improved. Thus, by improving the gas supply / discharge efficiency and the generated water discharge efficiency, according to the fuel cell of the present embodiment, the power generation efficiency can be improved.

  In the fuel cell of the present invention, since the effect of improving the gas supply / discharge efficiency is obtained by providing the pores 34 as described above, the gas flow path is used to improve the gas supply / discharge efficiency. There is no need to reduce the area of the contact portion between the forming member and the gas diffusion layer. That is, the gas supply / discharge efficiency can be improved while sufficiently securing the area of the contact portion with the gas diffusion layer. Therefore, even if the gas supply / discharge efficiency is improved, the current collecting performance is not impaired.

  In particular, in this embodiment, the total area of the region (substrate portion 30) that becomes the contact portion with the gas diffusion layer is larger than the total area of the region (the upper surface 32t of the convex portion 32) that becomes the contact portion with the separator. By forming the gas flow path forming member in this manner, the effect of improving the current collecting property with the catalyst layer is further enhanced. Thus, even if the contact portion with the gas diffusion layer is made larger, the gas diffusivity to the catalyst layer can be ensured by providing the pores 34 in the substrate portion 30. Can be made compatible.

  Here, by increasing the area of the contact portion with the gas diffusion layer in the gas flow path forming member, the current collecting property is improved through the gas diffusion layer of the electrolyte layer 21 having the catalyst layer on the surface. This is because a sufficient surface pressure can be applied to a wider area. In a region where the gas flow path forming member and the gas diffusion layer are not in contact with each other, sufficient pressure is not applied from the gas diffusion layer to the catalyst layer on the electrolyte layer 21, and contact between the gas diffusion layer and the catalyst layer is not achieved. There is a possibility that a region where it is difficult to secure an area may be generated. However, by increasing the contact area between the gas diffusion member and the gas diffusion layer, it is possible to ensure a sufficient contact area between the gas diffusion layer and the entire catalyst layer.

  In order to secure such a surface pressure through the gas diffusion layer with respect to the catalyst layer on the electrolyte layer 21 as described above, the gas flow path forming members 25 and 26 disposed on both surfaces of the electrolyte layer 21 are provided. It is desirable that the positions where the convex portions 32 are provided overlap each other. By applying a pressing force from both sides to the electrolyte layer 21 by the opposing substrate portion 30, it is possible to secure a more sufficient contact area in the catalyst layer.

  Furthermore, in the gas flow path forming member as described above, the pressure applied to the electrolyte layer 21 can be dispersed over the entire surface by increasing the total area of the contact portion with the gas diffusion layer from the separator side. Application of strong local pressure to the layer 21 can be prevented. Thereby, it becomes possible to improve the durability of the electrolyte layer 21 in the fuel cell.

  In addition, according to the present embodiment, the space formed by the gas flow path forming member having the concavo-convex shape is used as the gas flow path in the single cell, so that the pressure loss when the gas flows through the single cell is reduced. Can do. For example, the pressure loss when the gas passes through the single cell can be made extremely small as compared with the case where the entire gas flow path in the single cell is formed of a porous body made of carbon or metal. By reducing the pressure loss, the energy consumed to supply gas to the fuel cell can be reduced, and the efficiency of the entire system including the fuel cell can be improved. In addition, since the gas flow path forming member of the present embodiment is formed of a metal that is a material having excellent strength, when formed into an uneven shape that forms a space that becomes a gas flow path in a single cell as described above. In addition, sufficient strength can be maintained when a pressing force is applied in the stacking direction in the fuel cell.

  Further, in this embodiment, the concave and convex shape provided in the gas flow path forming member is a so-called staggered shape in which a plurality of rows in which convex portions 32 are arranged in one direction at equal intervals are arranged so that the rows are parallel to each other. Therefore, the gas passing through the gas flow path in the single cell can be effectively stirred. As a result, the gas supply efficiency to the catalyst layer through the gas diffusion layer can be improved, and the uniformity of gas distribution in the entire surface can be improved on each surface forming the gas flow path in the single cell. Can do. By improving the uniformity of gas distribution, the power generation amount in a single cell becomes more uniform over the entire surface, and the power generation efficiency of the fuel cell is improved.

  The pores provided in the gas flow path forming member may have a shape and size different from those in the embodiment, or the number of pores may be different from that in the embodiment. The larger the pores, the better the gas supply / exhaust efficiency with respect to the catalyst layer. However, the larger the total area of the pores, the smaller the substantial contact area between the substrate 30 and the gas diffusion layer. However, the battery performance does not always improve. Therefore, by providing a large number of small pores at short intervals rather than simply increasing the size of the pores, it is possible to achieve both gas supply / discharge efficiency and current collection performance, and to improve battery performance. it is conceivable that. The pore diameter can be, for example, about 0.1 mm to 1.0 mm, and the distance between the pores can be, for example, about 0.25 mm to 2.0 mm.

  Here, in the gas flow path forming member of the present embodiment, the pores 34 are not formed in the convex portion 32, but the pores 34 (the upper surface 32t or the side wall 32w) may be provided with the pores 34. . For example, in the pore forming step in step S110, the pores 34 may be formed uniformly on the entire surface of the metal plate member. In this case, the upper surface 32t or the side wall 32w includes the pores 34 in the convex portion 32 formed in the subsequent process.

C. Second embodiment:
In the first embodiment described above, the gas flow path forming member is produced by forming the pores 34 and the convex portions 32 by pressing the metal plate-like member. However, a different configuration may be used. For example, the gas flow path forming member may be produced by press-molding a plate-like member made of foam metal. Such a configuration will be described below as a second embodiment.

  The foam metal can be produced, for example, by mixing metal powder, a water-soluble binder, and a foaming agent to foam and then drying and sintering the mixture. Therefore, when producing the gas flow path forming member of the second embodiment, first, a plate-like member made of the above foam metal is prepared as step S100 of FIG. Thereafter, the cut portion 36 is formed in the same manner as in step S120 without performing the pore forming step in step S110. And the convex part 32 is further formed by overhang forming similarly to step S130, and a gas flow path formation member is completed. Such a gas flow path forming member of the second embodiment can be used in place of the gas flow path forming members 25 and 26 of the first embodiment in the fuel cell of the first embodiment.

  In the gas flow path forming member of the second embodiment configured as described above, the same effect as that of the first embodiment can be obtained. That is, since the gas flow path forming member is formed of a porous foam metal, the gas can flow through the pores provided in the foam metal, and even in a region covered with the substrate portion 30. In addition, it is possible to ensure gas supply / discharge of the catalyst layer. In addition, even in the region covered with the substrate part 30, the drainage of the generated water from the catalyst layer to the gas flow path in the single cell can be ensured. At this time, since the contact area between the gas flow path forming member and the gas diffusion layer can be sufficiently secured, the current collecting property is not impaired. Further, similarly to the first embodiment, the gas flow path forming member can be manufactured by a simple process of pressing the metal member. Further, by forming the gas flow path forming member with a member made of a metal material having an uneven shape capable of forming a predetermined space and having excellent strength, pressure loss in the gas flow path in the single cell can be reduced. .

  In addition, it is also possible to produce the gas flow path forming member similar to the second embodiment by a method other than press working. For example, the metal foam material may be sintered in a mold produced so as to have the same shape as that obtained by the press working.

D. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

D1. Modification 1 (Regarding the uneven shape):
The uneven shape of the gas flow path forming member may be different from those shown in FIGS. For example, the intervals between the convex portions 32 do not have to be all equal, or the sizes of the convex portions 32 do not have to be the same. The shape of the convex portion 32 does not have to be a substantially rectangular parallelepiped shape having the side wall 32w and the upper surface 32t as shown in FIG. 4, and the side wall and the upper surface may be formed by a continuous curved surface to form a corrugated uneven shape. If the convex portion 32 is provided so as to prevent the gas from flowing linearly in the gas flow path in the single cell, the gas distribution is made uniform in the surface and the gas is stirred to supply the gas to the catalyst layer. A similar effect of improving efficiency can be obtained.

  Further, in the embodiment, as shown in FIG. 2, the concavo-convex shape related to the gas flow path formation is formed over the entire surface of the fuel cell gas flow path forming member, but different shapes may be used. For example, the gas flow path forming member may have a shape related to the gas seal at the outer peripheral portion thereof. It is only necessary that the fuel cell gas flow path forming member has the concavo-convex portion having the concavo-convex shape described above in the region corresponding to the catalyst layer in which the cell reaction proceeds.

D2. Modification Example 2 (Regarding Method for Forming Uneven Shape):
The concavo-convex shape provided in the fuel cell gas flow path forming member may be formed by a method other than the method of projecting in one direction from the substrate portion as in the embodiment. For example, a notch portion similar to that of the embodiment may be formed in the substrate portion, and overhanging may be performed from the substrate portion in both directions. In this case, the convex portion formed by extending in one direction is in contact with the gas diffusion layer side, and the convex portion formed by extending in the other direction is in contact with the separator side. Or after forming the notch part similar to an Example, it is good also as forming in an uneven | corrugated shape by bending instead of overhang forming or in addition to overhang forming.

  In any case, a notch is formed in the metal plate-shaped member, and a molding process is performed on the region where the notch is formed, thereby forming a concavo-convex shape that communicates with both the front and back surfaces of the plate-shaped member through the notch. Thus, the same effect can be obtained. In addition, as a method for forming the concavo-convex shape for forming the predetermined space, a drawing process or the like that is not accompanied by a notch formation may be considered. For example, as shown in FIG. 6, it is possible to perform a deep drawing process on the plate-like member in which the pores are formed so as to form a convex portion for contacting the separator 27 side.

D3. Modification 3 (about manufacturing process):
Further, in the first and second embodiments, when forming the concavo-convex shape in the gas flow path forming member, the pores 34 are first formed by punching, and then the cut portions 36 are formed by shearing. Although the convex portion 32 is formed by the overhang processing, the processing may be performed in a different order. For example, the cut portions 36 may be formed before the formation of the pores 34, and the formation of the pores may be performed after the formation of the convex portions 32. Alternatively, a plurality of steps may be performed simultaneously.

D4. Modification 4 (Regarding the arrangement of members):
In the first and second embodiments, the gas flow path forming member is disposed on both pole sides, but the gas flow path forming member may be disposed only on one of the pole sides. Also in this case, the effects described above can be obtained on the side where the gas flow path forming member is provided. In the case where the gas flow path forming member is disposed only on one of the pole sides, it is particularly desirable that the gas flow path forming member is disposed on the cathode side. This is because generated water is generated on the cathode side during power generation, and drainage efficiency from the vicinity of the catalyst layer can be improved by providing a gas flow path forming member. When air is used as the oxidizing gas, the flow rate of the oxidizing gas is usually higher than the flow rate of the fuel gas. However, by providing a gas flow path forming member on the cathode side, the pressure on the oxidizing gas flow path side is increased. The loss can be suppressed, which is preferable. In the case where the gas flow path forming member is provided only on the cathode side, the fuel gas flow path in the single cell may be formed on the anode side only by the gas diffusion layer, for example.

  In the first and second embodiments, the gas diffusion layer is provided between the gas flow path forming member and the catalyst layer. However, the gas diffusion layer may not be provided. Here, the gas diffusion layer is usually formed of a member that is softer than the gas flow path forming member (the hardness of the constituent material is low or the compression elastic modulus as the member is high), and improves the current collecting property in the fuel cell. It is a member for. That is, since the gas diffusion layer is a member that can ensure a larger contact area with the catalyst layer than the gas flow path forming member, it is disposed between the catalyst layer and the gas flow path forming member. Thus, the current collecting property can be improved. However, if the current collecting property is in an allowable range, the catalyst layer and the gas flow path forming member may be brought into direct contact without providing a gas diffusion layer.

D5. Modification 5 (type of fuel cell):
In the first and second embodiments, the gas flow path forming member is provided in the polymer electrolyte fuel cell, but it can also be applied to different types of fuel cells. Even in other types of fuel cells, by providing the gas flow path forming member of the present invention to form the gas flow path in the single cell, the gas supply / discharge efficiency to the catalyst layer is improved and the generated water is generated. On the pole side, the same effect of improving drainage efficiency and improving battery performance can be obtained.

2 is a schematic cross-sectional view showing an outline of the configuration of a single cell 20. FIG. 3 is a plan view illustrating an outline of a configuration of a gas flow path forming member 25. FIG. It is sectional drawing of the gas flow path formation member 25 in the 3-3 cross section of FIG. It is a perspective view which expands and shows the mode of the area | region R shown in FIG. FIG. 10 is an explanatory diagram illustrating a manufacturing process of the gas flow path forming member 25. It is explanatory drawing showing a mode that the pore 34 was formed in the plate-shaped member. It is explanatory drawing showing a mode that the notch part 36 was formed.

Explanation of symbols

20 ... Single cell 21 ... Electrolyte layer 22, 23 ... Gas diffusion layer 25, 26 ... Gas flow path forming member 27, 28 ... Separator 30 ... Substrate part 32 ... Convex part 32e ... Opening part 32l ... Side 32p ... Opening part 32t ... Upper surface 32w ... side wall 34 ... pore 36 ... notch

Claims (6)

A fuel cell,
An electrolyte layer having a catalyst layer on the surface;
Used laminated together with the electrolyte layer has a flat surface and in said flat surface, and a separator which forms part of the passage wall of the flow channel of the gas supplied to the electrochemical reaction in the unit cells,
Metal fuel cell gas that is disposed between the electrolyte layer and the separator and that is in contact with the flat surface of the separator on one surface side to form a gas flow path for an electrochemical reaction A flow path forming member ;
Equipped with a,
The fuel cell gas flow path forming member comprises:
A flat substrate portion in contact with the adjacent member on the electrolyte layer side;
Together subjected to shearing to the substrate portion, by processing with elongation and / or bending of the substrate portion to shear the vicinity subjected to the shear processing, provided projected from the substrate portion A plurality of convex portions, wherein the upper surface of the convex portions is in contact with the separator ,
The plurality of convex portions have a shape in which a plurality of rows composed of the plurality of convex portions arranged in a row are arranged so that the rows are parallel to each other, and between adjacent rows, the rows are arranged in the rows. The convex portion is disposed so that the position of the convex portion shows a predetermined deviation with respect to a vertical direction,
The substrate portion is provided with a plurality of pores penetrating the substrate portion in the thickness direction between adjacent convex portions in the row and between adjacent convex portions between the different rows.
A fuel cell in which the gas flows in a direction perpendicular to a side wall surface of the convex portion in the gas flow channel formed by the fuel cell gas flow channel forming member . A fuel cells according to claim 1,
The fuel cell gas flow path forming member, the total area of the substrate portion in contact with adjacent members of said electrolyte layer side is formed to be larger than the total area of the upper surface of the convex portion in contact with the separator and fuel cells are. A fuel cell,
An electrolyte layer having a catalyst layer on the surface;
Used laminated together with the electrolyte layer has a flat surface and in said flat surface, and a separator which forms part of the passage wall of the flow channel of the gas supplied to the electrochemical reaction in the unit cells,
A metallic porous body disposed between the electrolyte layer and the separator and in contact with the flat surface of the separator on one surface side to form a gas flow path for an electrochemical reaction A fuel cell gas flow path forming member formed by :
Equipped with a,
The fuel cell gas flow path forming member comprises:
A flat substrate portion in contact with the adjacent member on the electrolyte layer side;
Together subjected to shearing to the substrate portion, by processing with elongation and / or bending of the substrate portion to shear the vicinity subjected to the shear processing, provided projected from the substrate portion A plurality of convex portions, wherein the upper surface of the convex portions is in contact with the separator ,
The plurality of convex portions have a shape in which a plurality of rows composed of the plurality of convex portions arranged in a row are arranged so that the rows are parallel to each other, and between adjacent rows, the rows are arranged in the rows. The convex portion is disposed so that the position of the convex portion shows a predetermined deviation with respect to a vertical direction,
A fuel cell in which the gas flows in a direction perpendicular to a side wall surface of the convex portion in the gas flow channel formed by the fuel cell gas flow channel forming member . A fuel cells according to claim 3,
The fuel cell gas flow path forming member, the total area of the substrate portion in contact with adjacent members of said electrolyte layer side is formed to be larger than the total area of the upper surface of the convex portion in contact with the separator and fuel cells are. A fuel cell according to any one of claims 1 to 4 ,
A fuel cell further comprising a gas diffusion layer made of a conductive porous body between the fuel cell gas flow path forming member and the catalyst layer. A fuel cell according to any one of claims 1 to 5,
  A pair of the catalyst layer, the fuel cell gas flow path forming member, and the separator are provided on both surfaces of the electrolyte layer, respectively.
  The pair of fuel cell gas flow path forming members are arranged such that contact portions that are in contact with adjacent members on the electrolyte layer side and contact portions that are in contact with the separator are in the stacking direction of the electrolyte layer and the separator. Provided to overlap each other in parallel directions
  Fuel cell.

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