JP2013058370A - Fuel cell stack, fuel cell stack complex, and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell stack that includes a plurality of fuel cells laminated in a thickness direction thereof and that enables an even supply of a liquid fuel to each of the fuel cells.SOLUTION: A fuel cell stack, a fuel cell stack complex, and a fuel cell system using the same, include: first fuel cells 20, each having a first membrane electrode assembly and a first fuel supply section 22 that has a first intracellular fuel passage 23; second fuel cells 20', each arranged above a main surface of each first fuel cell 20 and having a second membrane electrode assembly and a second fuel supply section 22' that has a second intracellular fuel passage 23'; and a fuel distribution section 10 that has a liquid fuel inlet 11 and an extracellular fuel passage 15 that connects the liquid fuel inlet 11 to the first and second intracellular fuel passages 23 and 23'. A fuel passage, including the first and second intracellular fuel passages 23 and 23' and the extracellular fuel passage 15, is configured in such a manner that pressure loss of a liquid fuel becomes higher beyond joints between the first and second intracellular fuel passages 23 and 23' and the extracellular fuel passage 15, or the neighborhood of the joints.

Description

  The present invention relates to a fuel cell stack in which a plurality of fuel cells are stacked in the thickness direction, a fuel cell stack complex in which a plurality of fuel cell stacks are stacked in the thickness direction, and a fuel cell stack or a fuel cell stack complex. The present invention relates to the fuel cell system used.

  Fuel cells are expected to be put to practical use as new power sources for portable electronic devices that support the information society. Fuel cells are classified into a phosphoric acid type, a molten carbonate type, a solid electrolyte type, a solid polymer type, a direct alcohol type, and the like according to the classification of the electrolyte material and fuel used. In particular, solid polymer fuel cells and direct alcohol fuel cells that use an ion exchange membrane, which is a solid polymer, as the electrolyte material can achieve high power generation efficiency at room temperature. Practical application as a small fuel cell is under study.

  A direct alcohol fuel cell using alcohol or an aqueous alcohol solution as a fuel (see, for example, Patent Document 1) is a fuel cell because the fuel tank can be designed relatively easily compared to the case where the fuel is a gas. The structure can be simplified and the space can be saved, and the expectation as a small fuel cell for application to portable electronic devices is particularly high.

JP 2008-235243 A

  In a fuel cell, a plurality of fuel cells are electrically connected and combined in order to increase the power, which is insufficient with one fuel cell, to a level sufficient as a new power source for portable electronic devices, for example. Has been performed conventionally. In this case, it is important that fuel can be supplied uniformly to each fuel cell. This is because when the fuel supply to each fuel cell becomes uneven, fuel shortage occurs, and a fuel cell that cannot sufficiently output is generated, and the output of the fuel cell as a whole decreases.

  The problem of such non-uniformity in the fuel supply is that when liquid fuel is supplied to each fuel cell via a flow path, the supply of the liquid fuel via the flow path is easily affected by gravity. A fuel cell in which another fuel cell is stacked on the main surface of the fuel cell, that is, a fuel cell in which a plurality of fuel cells are stacked in the thickness direction (in the present specification, such a fuel cell is referred to as a “fuel cell”). This is particularly noticeable in the “stack”.

  Patent Document 1 describes an invention whose technical problem is to uniformly supply fuel to fuel cells, but the uniform fuel supply in the document refers to a single fuel cell. This means uniformity in the anode electrode surface, and there is nothing about uniform fuel supply to a plurality of fuel cells, and hence uniform fuel supply to a plurality of fuel cells stacked in the thickness direction. No teaching is given.

  Accordingly, an object of the present invention is a fuel cell stack including a plurality of fuel cells stacked in the thickness direction, the fuel cell stack capable of uniformly supplying liquid fuel to each fuel cell, and a thickness thereof. An object of the present invention is to provide a fuel cell stack composite including a plurality of fuel cell stacks stacked in a direction, and a fuel cell system using the fuel cell stack or the fuel cell stack composite.

  In order to solve the above problems, the present invention provides a first membrane electrode assembly having a first anode electrode, a first electrolyte membrane, and a first cathode electrode in this order, and a first in-cell fuel for circulating liquid fuel. A first fuel cell having a flow path and including a first fuel supply unit disposed on the first anode electrode side, and a fuel cell disposed on a main surface of the first fuel cell, wherein A second membrane electrode assembly having two anode electrodes, a second electrolyte membrane, and a second cathode electrode in this order; and a second in-cell fuel flow path for allowing liquid fuel to circulate; A second fuel cell having a second fuel supply unit disposed on the fuel cell, and a fuel distributor coupled to the first and second fuel cells and for distributing liquid fuel to the first and second fuel cells And a fuel cell stack including a part

  Here, in the fuel cell stack of the present invention, the fuel distributor includes an inlet for introducing liquid fuel, and an out-cell fuel flow path connecting the inlet and the first and second in-cell fuel flow paths. It is what has. In the fuel cell stack of the present invention, the fuel flow path composed of the first and second in-cell fuel flow paths and the out-cell fuel flow paths is the first and second in-cell fuel flow paths and the out-cell fuel flow paths. With the boundary or the vicinity thereof as a boundary, the pressure loss of the liquid fuel flowing from the inlet to the first and second in-cell fuel flow paths via the out-cell fuel flow path is increased.

  In one preferred embodiment of the fuel cell stack according to the present invention, at least in the connection portion between the first and second in-cell fuel flow paths and the out-cell fuel flow path or in the vicinity thereof, the connection portion or the vicinity thereof is used as a reference. In addition, the cross-sectional area of the fuel flow path portion on the inlet side is larger than the cross-sectional area of the other fuel flow path portions. For example, at least in the connection portion between the first and second in-cell fuel flow paths and the out-cell fuel flow path, the cross-sectional area of the out-cell fuel flow path is larger than the cross-sectional area of the first and second in-cell fuel flow paths. large. In the present embodiment, in order to satisfy the relationship of the cross-sectional area, and thus the relationship of the pressure loss, the fuel at or near the connection portion between the first and second in-cell fuel flow paths and the out-cell fuel flow paths. A porous body can be filled in the flow path.

  The fuel flow path outside the cell of the fuel distribution unit includes a main flow path connected to the introduction port, and a first branch flow path that connects the end of the main flow channel opposite to the introduction port and the first in-cell fuel flow path. And a second branch channel connecting the end and the second in-cell fuel channel. In this case, the first and second branch flow paths can include a flow path portion extending in a substantially vertical direction with respect to the main surface of the first or second fuel cell.

  The first branch flow path and the first in-cell fuel flow path form a flow path extending in a substantially vertical direction with respect to the main surface of the first fuel cell at the connection portion, and the second branch flow path And the fuel flow path in the second cell may form a flow path extending in a substantially vertical direction with respect to the main surface of the second fuel cell at the connection portion. Alternatively, the first branch flow path and the first in-cell fuel flow path form a flow path extending substantially parallel to the main surface of the first fuel cell at the connection portion thereof, and the second branch flow path The second in-cell fuel flow path may form a flow path extending substantially parallel to the main surface of the second fuel cell at the connection portion.

  The first fuel cell and the second fuel cell may be spaced apart so that the first cathode electrode side and the second cathode electrode side face each other, or the cathode of either one of the fuel cells. The pole side and the fuel supply part side of the other fuel battery cell face each other (that is, the first cathode pole side and the second fuel supply part side face each other, or the second cathode pole side and the second fuel cell side 1 fuel supply part side may be arranged apart from each other.

  The fuel cell stack of the present invention can include two or more first fuel cells arranged on the same plane and two or more second fuel cells arranged on the same plane. For example, in one preferred embodiment, the fuel cell stack of the present invention includes a first fuel cell assembly composed of two or more first fuel cells arranged on the same plane, and the first fuel cell assembly. A second fuel cell comprising two or more second fuel cells disposed on the same plane and facing each of the first fuel cells. The battery cell assembly includes the fuel distribution unit coupled to all the first and second fuel cells.

  Preferably, the first fuel cell assembly includes two or more first fuel cells arranged in a line, and the second fuel cell assembly includes two or more second fuel cells arranged in a line. .

  Two or more first fuel cells in the first fuel cell assembly are arranged so that a gap is formed between two adjacent first fuel cells, and two or more first fuel cells in the second fuel cell assembly. The second fuel cell may be arranged such that a gap is formed between two adjacent second fuel cells. Alternatively, the first fuel cell assembly includes two or more first fuel cells arranged in a line without a gap, and the second fuel cell assembly includes two or more second fuel cells in a gap. Alternatively, it may be arranged in a line.

  The fuel cell stack of the present invention can be a direct alcohol fuel cell using alcohol or an aqueous alcohol solution as a liquid fuel.

  The present invention also provides a first fuel cell stack, which is the fuel cell stack according to the present invention, and a second fuel, which is the fuel cell stack according to the present invention, disposed on the main surface of the first fuel cell stack. A fuel cell stack composite comprising a battery stack is provided. In this fuel cell stack composite, the out-cell fuel flow path of the first fuel cell stack and the out-cell fuel flow path of the second fuel cell stack communicate with each other, and preferably at least these out-cell fuel flow paths In the connection portion of the path, the cross-sectional area of the out-cell fuel flow path of the second fuel cell stack is larger than the cross-sectional area of the out-cell fuel flow path of the first fuel cell stack.

  Furthermore, the present invention provides a fuel cell comprising the fuel cell stack or the fuel cell stack composite according to the present invention and a fuel tank for containing the liquid fuel connected to the fuel cell stack or the fuel cell stack composite. Provide a system. The fuel cell system may further include liquid feeding means for promoting the flow of liquid fuel from the fuel tank to the fuel cell stack or the fuel cell stack composite.

  According to the present invention, in a fuel cell stack including a plurality of fuel cells stacked in the thickness direction, the supply of liquid fuel to each fuel cell is made uniform, and thus a fuel cell stack that exhibits high output, In addition, a fuel cell stack composite and a fuel cell system using the same can be provided.

1 is a schematic perspective view showing an example of a fuel cell stack according to the present invention. It is a schematic sectional drawing in the II-II line | wire shown by FIG. It is a schematic sectional drawing which shows another example of the fuel cell stack which concerns on this invention. It is a schematic sectional drawing which shows another example of the fuel cell stack which concerns on this invention. It is a schematic sectional drawing which shows the example of a shape of a fuel flow path outside a cell. It is a schematic sectional drawing which shows another example of the fuel cell stack which concerns on this invention. It is a schematic sectional drawing which shows an example of the laminated constitution of a 1st fuel cell. (A) is a schematic top view which shows an example of a 1st flow-path board, (b) is a schematic sectional drawing of the fuel distribution part in the VIII-VIII line shown by (a). (A) is a schematic top view which shows another example of a 1st flow-path board, (b) is a schematic sectional drawing of the fuel distribution part in the IX-IX line shown by (a). It is a schematic top view which shows another example of a 1st flow-path board. It is the schematic top view and schematic sectional drawing which show an example of a 1st vaporization fuel board. It is the schematic top view and schematic sectional drawing which show the other example of a 1st vaporization fuel board. It is a schematic perspective view which shows another example of the fuel cell stack which concerns on this invention. 1 is a schematic perspective view showing an example of a fuel cell stack composite according to the present invention. It is a schematic perspective view which shows another example of the fuel cell stack composite body which concerns on this invention. 1 is a schematic perspective view showing an example of a fuel cell system according to the present invention. It is a schematic sectional drawing which shows an example of the fuel cell system which concerns on this invention. It is a figure which shows the result of having measured the IV characteristic about the fuel cell stack of Example 1. FIG. It is a figure which shows the result of having measured the IV characteristic about the fuel cell stack of the comparative example 1.

Hereinafter, the present invention will be described in detail with reference to embodiments.
<Fuel cell stack>
FIG. 1 is a schematic perspective view showing an example of a fuel cell stack according to the present invention, and FIG. 2 is a schematic sectional view taken along line II-II shown in FIG. The fuel cell stack 1 shown in these drawings includes a total of 20 fuel cells (10 first fuel cells 20 and 10 second fuel cells 20 ′), and the fuel cells. It is composed of a fuel distributor 10 that is connected to all of the fuel cells and distributes and supplies liquid fuel to each fuel cell.

[1] Overall Structure The fuel cell stack 1 includes a first fuel cell assembly 40 including five first fuel cells 20 that are spaced apart from each other on the same plane and arranged in a line; Are separated from each other and arranged in a line, and are arranged on the main surface of the first fuel cell assembly 40 (in the thickness direction of the first fuel cell assembly 40). And a second fuel cell assembly 50 spaced from the first fuel cell assembly 40; and all the first and second fuel cells 20, 20 ′ (all The fuel distribution unit 10 is coupled to the first and second fuel cell assemblies 40, 50). The fuel distribution unit 10 includes first and second fuel cell assemblies that are arranged in parallel and opposite to the arrangement direction of fuel cells constituting the fuel cell assembly (longitudinal direction of the fuel cell assembly). The first and second fuel cells 20 and 20 ′ constituting the first and second fuel cell assemblies 40 and 50 disposed on the side of the bodies 40 and 50 and facing each other on the side surfaces thereof Are combined.

  In this example, the fuel cell stack 1 has a total of two first fuel cell assemblies 40 and a total of two second fuel cell assemblies 50 coupled to opposite side surfaces of the fuel distributor 10. ing. The fuel cells constituting the fuel cell stack 1 are electrically connected in series and / or in parallel.

  Further, the first fuel cell assembly 40 and the second fuel cell assembly 50 are spaced apart from each other, so that the first and second fuel cell assemblies 40, 50 are interposed between them. A space 30 is formed. This space 30 constitutes a supply path for an oxidizing agent (air or the like).

  All of the second fuel cells 20 ′ constituting the second fuel cell assembly 50 are arranged below (opposed to) the first fuel cells 20 constituting the first fuel cell assembly 40. (The first fuel cell 20 is disposed immediately below the second fuel cell 20 ′). The main surface of the first fuel cell 20 and the second fuel cell 20 'are substantially parallel. The first fuel cell 20 and the second fuel cell 20 ′ are spaced apart so that their cathode electrodes face each other (so that the first cathode electrode side and the second cathode electrode side face each other). ing.

  The first fuel cell 20 includes a first power generation unit 21 including a first membrane electrode assembly having a first anode electrode, a first electrolyte membrane, and a first cathode electrode in this order, and a first power generation unit 21 of the first power generation unit 21. It comprises at least a first fuel supply unit 22 arranged on the anode electrode side (see FIG. 1). The first fuel supply unit 22 has a first in-cell fuel flow path 23 for flowing liquid fuel (or diffusing and flowing in the surface of the fuel cell) [see FIG. 2]. Similarly, the second fuel cell 20 ′ includes a second power generation unit 21 ′ including a second membrane electrode assembly having a second anode electrode, a second electrolyte membrane, and a second cathode electrode in this order, and a second power generation unit. And at least a second fuel supply unit 22 ′ arranged on the second anode electrode side of the unit 21 ′ (see FIG. 1). The second fuel supply unit 22 ′ has a second in-cell fuel flow path 23 ′ for circulating liquid fuel (or diffusing and circulating in the surface of the fuel cell) [see FIG. 2].

  The fuel distribution unit 10 is a part for distributing and supplying the liquid fuel to the first and second fuel cells 20, 20 ′, and has an introduction port 11 for introducing the liquid fuel on any surface. In addition, an out-cell fuel flow path 15 that connects the introduction port 11 and the first and second in-cell fuel flow paths 23, 23 'of the first and second fuel cells 20, 20' is provided inside. [See FIG. 2]. In the fuel cell stack 1, the introduction port 11 is an upper surface (a surface forming the same surface as the main surface of the second fuel cell assembly 50 opposite to the first fuel cell assembly 40), The distribution unit 10 is provided at a central portion in the longitudinal direction (a position corresponding to a central portion of the central fuel cell constituting the fuel cell assembly in the longitudinal direction of the fuel cell assembly).

[2] Fuel channel structure The fuel cell stack 1 has a fuel channel for supplying liquid fuel to each fuel cell constituting the fuel cell stack 1, and as described above, Intra-cell fuel flow paths (first and second in-cell fuel flow paths 23, 23 ') of the fuel battery cell, and first and second in-cell fuel flow paths 23 provided in the fuel distributor 10, It consists of an out-cell fuel flow path 15 connected to 23 '.

  Referring to FIG. 2, the out-cell fuel flow path 15 is located below the first fuel cell 20 (and the second fuel battery cell 20 ′) from the introduction port 11 in a substantially vertical direction (first fuel). A first main flow path 16 extending in a direction approaching the battery cell 20; connected to the end 16 A of the first main flow path 16 opposite to the introduction port 11, and connected to the first fuel battery cell 20 (and the second fuel battery cell 20). ') And the second main flow path 17 (hereinafter referred to as the first main flow path 16 and the second main flow path 17) extending substantially parallel to the main surface (in the direction approaching the fuel cell assembly). The end portion of the main channel 18 opposite to the inlet 11 (the end of the second main channel 17 opposite to the end 16A) 17A and the first in-cell fuel channel 23 are connected. The first branch channel 19a; and the end portion 17A and the second in-cell fuel channel 23 '. Including a second branch passage 19b that connects.

  In the cross section shown in FIG. 2, the second main flow path 17 is formed on the both side surfaces from the end portion 16 </ b> A in order to enable fuel supply to the fuel cell assembly group disposed on both side surfaces of the fuel distribution unit 10. A total of two are extended toward The first and second branch channels 19a and 19b extend in a substantially vertical direction with respect to the main surface of the first fuel cell 20 (and the second fuel cell 20 ').

  Although not shown, the out-cell fuel flow path 15 is used to supply liquid fuel to fuel cells other than the central fuel cells constituting the first and second fuel cell assemblies 40, 50. A third main channel extending from the end 16A in the longitudinal direction of the fuel distributor 10 (the arrangement direction of the fuel cells constituting the first and second fuel cell assemblies 40, 50) is provided as a part of the main channel 18. doing. The third main channel is connected to the in-cell fuel channel of each fuel cell other than the central fuel cell, and the second main channel 17 and the first and second branches having the same structure as in FIG. Channels 19a and 19b are provided. That is, the fuel cell stack 1 includes one first main channel 16, a total of ten second main channels 17, a third main channel, a total of ten first branch channels 19a, and a total of ten A second branch channel 19b is provided.

  In the present specification, the “main flow path” which is a part of the fuel flow path refers to the liquid fuel to be distributed and supplied to the first fuel battery cell 20 and the second fuel battery cell 20 ′ that are arranged to face each other. It is a flow path that flows in common, and more specifically means a fuel flow path other than the in-cell fuel flow path and the first and second branch flow paths.

  Here, the fuel flow path in the fuel cell stack 1 is such that the cross-sectional area of the out-cell fuel flow path 15 is larger than the cross-sectional areas of the first and second in-cell fuel flow paths 23 and 23 ', thereby The cross-sectional area 15 of the out-cell fuel flow path at the connection portion between the second in-cell fuel flow path 23, 23 ′ and the out-cell fuel flow path 15 is the cross-sectional area of the first and second in-cell fuel flow paths 23, 23 ′. By making it larger, the pressure loss of the liquid fuel flowing from the introduction port 11 to the first and second in-cell fuel flow paths 23 and 23 ′ from the introduction port 11 through the connection portion becomes larger. It is comprised so that it may become. In the example of FIG. 2, the cross-sectional areas of the cross-sectional areas of the out-cell fuel flow path 15 and the first and second in-cell fuel flow paths 23 and 23 ′ are constant throughout, but are not limited thereto.

  According to the fuel cell stack 1 that satisfies the above-described cross-sectional area relationship and thus the pressure loss relationship, the in-cell fuel flow paths 23 and 23 are filled after all the in-cell fuel flow paths 15 are filled with the liquid fuel. Since the liquid fuel is supplied to the first and second branches, the fuel flow path extends in a direction substantially perpendicular to the main surface of the first fuel cell 20 (and the second fuel cell 20 ′). Despite including the flow paths 19a and 19b, it becomes possible to supply the liquid fuel uniformly to the first fuel cell 20 and the second fuel cell 20 ′ stacked in the thickness direction.

The cross-sectional area of the out-cell fuel flow path 15 can be, for example, in the range of 100 μm ^{2 to 1} mm ² , and the cross-sectional areas of the first and second in-cell fuel flow paths 23, 23 ′ are, for example, 2500 μm ² , respectively. It can be in the range of 10000 μm ² . The cross-sectional area of the first in-cell fuel flow path 23 and the cross-sectional area of the second in-cell fuel flow path 23 ′ may be the same or different, but the first fuel cell 20 and the second fuel cell. In order to further improve the uniformity of fuel supply to 20 ', the same is preferable.

  As in the above-described example, the fuel cell stack of the present invention has a pressure loss of the liquid fuel flowing from the inlet 11 to the first and second in-cell fuel flow paths 23 and 23 ′ via the out-cell fuel flow path 15. Although the fuel flow path is configured so as to increase from a certain point as a boundary, means for satisfying such a relationship of pressure loss is not limited to that illustrated in FIG.

  For example, the “certain point” is not limited to the connection portion between the first and second in-cell fuel flow paths 23, 23 ′ and the out-cell fuel flow path 15, but in the vicinity thereof as in the example of FIG. (For example, the vicinity of the connecting portion in the out-cell fuel flow path 15) may be used. If a pressure loss change point is provided at a position away from the connecting portion, disproportionation of the fuel supply will occur between reaching the first and second in-cell fuel flow paths 23, 23 'from the pressure loss change point. May occur.

  In the example of FIG. 3, the cross-sectional area of the second main flow path 17 is made larger than the cross-sectional areas of the first and second branch flow paths 19a and 19b, thereby the second main flow path 17 and the first and second branch flows. The connection portion in the connection portion with the passages 19a and 19b (the connection portion is in the vicinity of the connection portion between the first and second in-cell fuel flow paths 23 and 23 'and the out-cell fuel flow path 15) As a reference, the cross-sectional area of the fuel flow path portion (that is, the main flow path 18) on the inlet 11 side is defined as the other fuel flow path portions (that is, the first and second branch flow paths 19a and 19b, and the fuel flow in the cell). By making it larger than the cross-sectional area of the passages 23, 23 '), the above pressure loss relationship is satisfied. In the example of FIG. 3, the cross-sectional area of the first and second in-cell fuel flow paths 23, 23 ′ at the connection portion between the first and second in-cell fuel flow paths 23, 23 ′ and the out-cell fuel flow path 15 The cross-sectional area of the out-cell fuel flow path 15 is the same.

  Thus, in order to satisfy the relationship of the pressure loss, at least in the connection portion between the first and second in-cell fuel flow paths 23, 23 ′ and the out-cell fuel flow path 15 or in the vicinity thereof, the connection portion Alternatively, the cross-sectional area of the fuel flow path portion on the introduction port 11 side may be made larger than the cross-sectional area of the other fuel flow path portions with reference to the vicinity thereof. In such a configuration, the point where the cross-sectional area changes becomes the pressure loss change point, and after all the fuel flow paths up to the pressure loss change point are filled with the liquid fuel, the in-cell fuel flow paths 23, 23 Since the liquid fuel is supplied to ', the liquid fuel can be supplied uniformly to the first fuel cell 20 and the second fuel cell 20' stacked in the thickness direction.

  As shown in the example of FIG. 3, when the cross-sectional area of the first main channel 16 is further increased compared to the cross-sectional area of the second main channel 17, liquid fuel is introduced using a liquid-feeding means such as a liquid-feed pump. In the case of introducing into the port 11, it is possible to use a liquid delivery means having a small discharge pressure and thus a small size, which is advantageous in terms of downsizing the fuel cell system.

  Further, in order to satisfy the relationship of the pressure loss, as shown in FIG. 4, at or near the connection portion between the first and second in-cell fuel flow paths 23, 23 ′ and the out-cell fuel flow path 15. The porous body 60 may be filled in the fuel flow path. Rather than adjusting the width and depth of the fuel flow path, the cross-sectional area of the fuel flow path can also be adjusted by filling such a porous body 60. That is, by filling the porous body 60, the cross-sectional area of the fuel flow path part on the inlet 11 side is set to the other fuel flow path part (including the porous body 60) with reference to the filling position of the porous body 60. It can be larger than the cross-sectional area.

  The porous body 60 is made of a material that is insoluble in liquid fuel. Specifically, cellulose; polyolefin resin such as polyethylene and polypropylene; fluorine resin such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); acrylic resin; polyester resin such as polyethylene terephthalate; polyurethane Polyamide resins; Polyacetal resins; Polycarbonate resins; Chlorine resins such as polyvinyl chloride; Polyether resins; Polyphenylene resins and the like. What was made into the form of a solid body, a foam, a fiber bundle, a woven fiber, a non-woven fiber etc. can be used as the porous body 60. FIG.

  Further, as another means for satisfying the pressure loss relationship, at least in the connection portion between the first and second in-cell fuel flow paths 23, 23 ′ and the out-cell fuel flow path 15 or in the vicinity thereof, The hydrophilicity (wetting property) of the inner wall surface of the fuel flow path portion on the introduction port 11 side is made larger than the hydrophilicity (wetting property) of the inner wall surface of the other fuel flow path portions based on the vicinity thereof. It is done. Even by such adjustment of the hydrophilicity of the inner wall surface of the fuel flow path, the point where the hydrophilicity changes becomes the pressure loss change point, and after all the fuel flow paths up to the pressure loss change point are filled with the liquid fuel, Since the liquid fuel is supplied to the in-cell fuel flow paths 23 and 23 ', the liquid fuel is uniformly supplied to the first fuel cell 20 and the second fuel cell 20' stacked in the thickness direction. It becomes possible.

  The shape of the out-cell fuel flow path 15 is not limited to that shown in FIG. 2 and may take various shapes, but is usually distributed and supplied to the first fuel cell 20 and the second fuel cell 20 ′. A main flow path 18 through which the liquid fuel to be common flows, and first and second branch flow paths 19a and 19b branched from the main flow path 18 are provided. Regarding the shape of the main flow path 18 as well, the first main flow path 16 extending in a direction substantially perpendicular to the main surface of the first fuel cell 20 and the second main flow extending substantially parallel to the main surface of the first fuel cell 20. It is not limited to what is shown in FIG. 2 which consists of the path | route 17, A various shape can be taken.

  In the example of FIG. 2 and the like, the first and second branch channels 19a and 19b extend in a direction substantially perpendicular to the main surface of the first fuel cell 20 (and the second fuel cell 20 ′). However, the present invention is not limited to this, and may be an oblique flow path that extends directly from the end portion 16A to the inlet end portions of the first and second in-cell fuel flow paths 23, 23 ′. In this case, the out-cell fuel flow path 15 does not have the second main flow path 17.

  As shown in FIG. 5, it is also preferable to add R to the branch portion (for example, the end portions 16 </ b> A and 17 </ b> A) of the flow path in the out-cell fuel flow path 15 (the corners are formed of curved surfaces). Thereby, since the variation in the pressure loss of the liquid fuel at the branching portion can be reduced, more uniform fuel supply to the first fuel cell 20 and the second fuel cell 20 ′ stacked in the thickness direction is possible. It becomes. FIG. 5A shows an example in which R is added to the out-cell fuel flow path 15 shown in FIG. 2, and FIG. 5B shows an example in which R is added to the out-cell fuel flow path 15 shown in FIG. is there.

  2 to 4, the first branch flow path 19a and the first in-cell fuel flow path 23, and the second branch flow path 19b and the second in-cell fuel flow path 23 'are connected to each other. In the portion, the first fuel cell 20 and the second fuel cell 20 'are connected so as to form a flow path extending in a substantially vertical direction with respect to the main surfaces of the first fuel cell 20 and the second fuel cell 20', but the present invention is not limited to this. For example, as shown in FIG. 6, the first branch channel 19a and the first in-cell fuel channel 23, and the second branch channel 19b and the second in-cell fuel channel 23 ′ are connected to each other. The first fuel cell 20 and the second fuel cell 20 ′ may be connected so as to form a flow path extending substantially parallel to the main surface. In this case, the first and second branch flow channels 19a and 19b are, for example, substantially L-shaped formed of a flow channel portion extending in a substantially vertical direction and a flow channel portion extending substantially parallel to the main surface of the fuel cell. The first and second in-cell fuel flow paths 23, 23 ′ can be flow paths extending substantially parallel to the main surface of the fuel cell.

  The fuel flow path structure shown in FIG. 6 is similar to FIG. 3 in the vicinity of the connection portion between the first and second in-cell fuel flow paths 23, 23 ′ and the out-cell fuel flow path 15. This is an example in which the cross-sectional area of the fuel flow path portion on the inlet 11 side is made larger than the cross-sectional areas of the other fuel flow path portions.

  In the fuel flow path structure as in the example of FIG. 6, a part of the fuel distributor 10 (region indicated by Y in FIG. 6) can be omitted or the width of the region can be reduced. The advantage is that the width, and thus the width of the fuel cell stack, can be reduced.

[3] First Fuel Battery Cell FIG. 7 is a schematic cross-sectional view showing an example of the layer configuration of the first fuel battery cell 20, and shows a cross section in a direction perpendicular to the cross section shown in FIG. is there. In the example shown in FIG. 7, the first fuel cell 20 includes a first membrane electrode assembly 104 having a first anode electrode 102, a first electrolyte membrane 101, and a first cathode electrode 103 in this order; A first anode current collecting layer 105 laminated on and electrically connected thereto; a first cathode current collecting layer 106 laminated on and electrically connected to the first cathode electrode 103; a first anode A first anode moisturizing layer 107 laminated on the first anode current collecting layer 105 so as to be in contact with the current collecting layer 105; and laminated on the first cathode current collecting layer 106 so as to be in contact with the first cathode current collecting layer 106 First cathode moisturizing layer 108; a first flow path plate disposed on the first anode electrode 102 side and having a first in-cell fuel flow path 23 for flowing liquid fuel (diffusing and flowing in the fuel cell surface). 22 A liquid fuel disposed between the first membrane electrode assembly 104 and the first flow path plate 22a on the surface of the first flow path plate 22a so as to cover the first in-cell fuel flow path 23; A first gas-liquid separation layer 112 that is permeable to vaporized components; and a first vaporized fuel plate that is disposed between the first gas-liquid separation layer 112 and the first anode moisturizing layer 107 and includes a vaporized fuel storage portion 113a. 113.

  In the example shown in FIG. 7, the first power generation unit 21 includes a first cathode moisture retention layer 108, a first cathode current collection layer 106, a first membrane electrode assembly 104, a first anode current collection layer 105, and a first anode moisture retention layer. The first fuel supply unit 22 includes a first vaporized fuel plate 113, a first gas-liquid separation layer 112, and a first flow path plate 22a.

(First electrolyte membrane)
The first electrolyte membrane 101 constituting the first membrane electrode assembly 104 has a function of transmitting protons from the first anode electrode 102 to the first cathode electrode 103, and the electric power between the first anode electrode 102 and the first cathode electrode 103. It has the function of maintaining the electrical insulation and preventing short circuit. The material of the first electrolyte membrane 101 is not particularly limited as long as it has proton conductivity and electrical insulation, and a polymer membrane, an inorganic membrane, or a composite membrane can be used. As the polymer membrane, for example, Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), which is a perfluorosulfonic acid electrolyte membrane, etc. Can be mentioned. Also, styrene-based graft polymer, trifluorostyrene derivative copolymer, sulfonated polyarylene ether, sulfonated polyetheretherketone, sulfonated polyimide, sulfonated polybenzimidazole, phosphonated polybenzimidazole, sulfonated polyphosphazene. Hydrocarbon electrolyte membranes such as can also be used.

  Examples of the inorganic film include films made of phosphate glass, cesium hydrogen sulfate, polytungstophosphoric acid, ammonium polyphosphate, and the like. Examples of the composite film include a composite film of an inorganic material such as tungstic acid, cesium hydrogen sulfate, and polytungstophosphoric acid and an organic material such as polyimide, polyetheretherketone, and perfluorosulfonic acid. The thickness of the first electrolyte membrane 101 is, for example, 1 to 200 μm.

(First anode electrode and first cathode electrode)
The first anode electrode 102 laminated on one surface of the first electrolyte membrane 101 and the first cathode electrode 103 laminated on the other surface each have a catalyst layer comprising a porous layer containing at least a catalyst and an electrolyte. Is provided. In the first anode electrode 102, a catalyst (anode catalyst) catalyzes a reaction of generating protons and electrons from the fuel, and the electrolyte has a function of conducting the generated protons to the first electrolyte membrane 101. In the first cathode electrode 103, the catalyst catalyzes a reaction of generating water from protons conducted through the electrolyte and an oxidant (such as air).

  The catalyst of the first anode electrode 102 and the first cathode electrode 103 may be supported on the surface of a conductor such as carbon or titanium, and in particular, carbon or titanium having a hydrophilic functional group such as a hydroxyl group or a carboxyl group. It is preferable to be carried on the surface of a conductor such as. Thereby, the water retention of the first anode electrode 102 and the first cathode electrode 103 can be improved. By improving the water retention, the resistance of the first electrolyte membrane 101 accompanying proton transfer and the potential distribution in the first anode electrode 102 and the first cathode electrode 103 can be improved.

  Each of the first anode electrode 102 and the first cathode electrode 103 includes an anode conductive porous layer (anode gas diffusion layer) and a cathode conductive porous layer (cathode gas diffusion layer) laminated on the catalyst layer. Also good. These conductive porous layers have a function of diffusing gas (vaporized fuel or oxidant) supplied to the first anode electrode 102 and the first cathode electrode 103 in the plane, and exchange of electrons with the catalyst layer. Has the function to perform. As the anode conductive porous layer and the cathode conductive porous layer, since the specific resistance is small and the decrease in voltage is suppressed, carbon materials; conductive polymers; noble metals such as Au, Pt, Pd; Ti, Porous materials comprising transition metals such as Ta, W, Nb, Ni, Al, Cu, Ag, Zn; nitrides or carbides of these metals; and alloys containing these metals typified by stainless steel Is preferably used. In the case of using a metal having poor corrosion resistance in an acidic atmosphere, such as Cu, Ag, Zn, etc., noble metals having resistance to corrosion such as Au, Pt, Pd, conductive polymers, conductive nitrides, conductive Surface treatment (film formation) may be performed with carbide, conductive oxide, or the like. More specifically, as the anode conductive porous layer and the cathode conductive porous layer, for example, foam metal, metal fabric and metal sintered body made of the above-mentioned noble metal, transition metal or alloy; and carbon paper, carbon cloth, An epoxy resin film containing carbon particles can be suitably used.

(First anode current collecting layer and first cathode current collecting layer)
The first anode current collecting layer 105 and the first cathode current collecting layer 106 are laminated on the first anode electrode 102 and the first cathode electrode 103, respectively. The first anode current collecting layer 105 and the first cathode current collecting layer 106 have a function of collecting electrons in the first anode electrode 102 and the first cathode electrode 103 and a function of performing electrical wiring, respectively. The material of the current collecting layer is preferably a metal because it has a small specific resistance and suppresses a decrease in voltage even when a current is taken in the plane direction. In particular, it has electron conductivity and has an acidic atmosphere. More preferably, the metal has corrosion resistance. Such metals include noble metals such as Au, Pt, Pd; transition metals such as Ti, Ta, W, Nb, Ni, Mo, Co, Al, Cu, Ag, Zn; and nitrides of these metals or Carbides and the like; and alloys containing these metals typified by stainless steel. In the case of using a metal having poor corrosion resistance in an acidic atmosphere, such as Cu, Ag, Zn, etc., noble metals having resistance to corrosion such as Au, Pt, Pd, conductive polymers, conductive nitrides, conductive Surface treatment (film formation) may be performed with carbide, conductive oxide, or the like. When the anode conductive porous layer and the cathode conductive porous layer are made of, for example, metal and the conductivity is relatively high, the first anode current collecting layer and the first cathode current collecting layer are omitted. Also good.

More specifically, the first anode current collecting layer 105 has a mesh shape made of the above metal material or the like having a plurality of through holes (openings) penetrating in the thickness direction for guiding the vaporized fuel to the first anode electrode 102. Or it can be a flat plate having a punching metal shape. This through-hole also functions as a path for guiding by-product gas (CO ₂ gas or the like) generated in the catalyst layer of the first anode electrode 102 to the vaporized fuel storage portion 113a side. Similarly, the first cathode current collecting layer 106 includes a plurality of through holes (openings) penetrating in the thickness direction for supplying an oxidizing agent (for example, air outside the fuel cell) to the catalyst layer of the first cathode electrode 103. It can be a flat plate having a mesh shape or a punching metal shape made of the above metal material.

(First flow path plate)
The first flow path plate 22a may be a plate-like body in which a first in-cell fuel flow path 23 for flowing liquid fuel is formed on the surface of the first anode electrode 102 side. The first in-cell fuel flow path 23 can be composed of, for example, a groove (concave portion) formed on one surface of the plate-like body. The shape (pattern) of the first in-cell fuel flow path 23 is not particularly limited, and is uniformly arranged over the widest possible range of the flow path plate surface so that vaporized fuel can be supplied as uniformly as possible to the entire surface of the first anode electrode 102. It is preferable.

  8 to 10 show examples of flow path patterns of the first in-cell fuel flow path 23. FIG. Each of the first in-cell fuel flow paths 23 (shaded portions) shown in FIGS. 8 to 10 is formed of a groove (concave portion). 8A and 9A are schematic top views showing the formation surface of the first in-cell fuel flow path 23 in the first flow path plate 22a. For example, as shown in FIG. A schematic top view showing a state in which a part of the fuel distribution section 10 is laminated on the first flow path plate 22a so that the passage 23 and the out-cell fuel flow path 15 of the fuel distribution section 10 are connected. It is. FIGS. 8 and 8B are schematic cross-sectional views of the fuel distributor 10 taken along lines VIII-VIII and IX-IX shown in FIGS. 8A and 9A, respectively.

  In the example of FIG. 8, the connection point between the first in-cell fuel flow path 23 of the first flow path plate 22a and the out-cell fuel flow path 15 (more specifically, the first branch flow path 19a) of the fuel distributor 10. Is only one point (that is, there is only one inlet for the first in-cell fuel flow path 23), but the first in-cell fuel flow paths 23 extend in parallel with each other at regular intervals. It has a structure branched in a comb-teeth shape so as to have five branch channels. With such a branched structure, vaporized fuel can be supplied uniformly over the entire surface of the first anode electrode 102.

  In the example of FIG. 9, the first branch flow path 19a of the out-cell fuel flow path 15 is branched (see FIG. 9B), and accordingly, a plurality of inlets of the first in-cell fuel flow path 23 are provided. The first in-cell fuel flow path 23 is composed of a plurality of branch flow paths as in the example of FIG.

  FIG. 10 is a schematic top view showing another example of the first flow path plate, and shows another example of the flow path pattern of the fuel flow path 23 in the first cell. The flow channel shape of FIG. 10 is similar to that of FIG. 9, but the first in-cell fuel flow channel 23 extends to one end surface (side surface) of the first flow channel plate 22a, and the four inlets are on the end surface. It differs from FIG. 9 in that it is provided. The flow path plate having such a structure can be used in the form of connecting the in-cell fuel flow path and the out-cell fuel flow path on the side surface of the flow path plate as in the fuel cell stack shown in FIG.

  For the first in-cell fuel flow path 23 having a predetermined depth, the thickness of the first flow path plate 22a is adjusted, or the first vaporized fuel plate 113 stacked on the first flow path plate 22a and By adjusting the thickness of the first gas-liquid separation layer 112 (in some cases, the first vaporized fuel plate 113 and / or the first gas-liquid separation layer 112 is omitted), The position in the thickness direction of the first in-cell fuel flow path 23 can be adjusted.

  The first flow path plate 22a can be made of a plastic material or a metal material. Examples of the plastic material include polyphenylene sulfide (PPS), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polyvinyl chloride, polyethylene (PE), polyethylene terephthalate (PET), polyether ether ketone (PEEK). ), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and the like. As the metal material, for example, alloy materials such as stainless steel and magnesium alloy can be used in addition to titanium and aluminum.

(First vaporized fuel plate)
FIG. 11A is a schematic top view showing the first vaporized fuel plate 113 used in the first fuel cell 20 shown in FIG. 7, and FIG. 11B is the XI shown in FIG. It is a schematic sectional drawing in the -XI line. The first vaporized fuel plate 113 is a member for forming a space for accommodating vaporized fuel (that is, the vaporized fuel accommodating portion 113a) between the first membrane electrode assembly 104 and the first gas-liquid separation layer 112. It is. In the example of FIG. 7, the first vaporized fuel plate 113 is disposed between the first anode moisturizing layer 107 and the first gas-liquid separation layer 112 so as to be in contact with the first anode moisturizing layer 107. The first vaporized fuel plate 113 includes a vaporized fuel storage portion 113a that is a through-hole penetrating in the thickness direction, and a communication path 113b that allows the vaporized fuel storage portion 113a and the first vaporized fuel plate 113 to communicate with each other. The communication path 113b is a path for discharging by-product gas (CO ₂ gas or the like) generated at the first anode electrode 102 to the outside of the fuel cell.

  The communication path 113b includes a groove (concave portion) that is provided at the peripheral portion of the first vaporized fuel plate 113 and extends from the vaporized fuel storage portion 113a to the end surface of the peripheral portion. The outlet of the communication path 113b is provided, for example, on the side surface facing the side surface of the fuel cell to which the fuel distribution unit 10 is coupled.

  By providing the vaporized fuel storage portion 113a on the first in-cell fuel flow path 23 via the first gas-liquid separation layer 112, the concentration of the vaporized fuel supplied to the first anode electrode 102 is within the surface of the first anode electrode 102. And the optimization of the amount of vaporized fuel is promoted.

Providing the vaporized fuel storage portion 113a is also advantageous in the following points.
(I) Thermal insulation between the first membrane electrode assembly 104 and the first in-cell fuel flow path 23 can be achieved by the air layer present in the vaporized fuel accommodating portion 113a. Thereby, the crossover by the temperature of the liquid fuel in the 1st cell fuel flow path 23 rising excessively can be suppressed. This contributes to suppression of runaway internal temperature of the fuel cell and increase in internal pressure.

(Ii) A by-product gas such as CO ₂ gas generated at the first anode electrode 102 reaches the vaporized fuel storage portion 113a with heat generated by power generation, and then passes through the communication path 113b to form a fuel cell. It is discharged outside the cell. As a result, the amount of heat accumulated inside the fuel cell can be significantly reduced, so that an excessive temperature rise as the entire fuel cell including the first in-cell fuel flow path 23 can be suppressed. This also contributes to suppression of runaway internal temperature of the fuel battery cell and increase in internal pressure. In particular, since the first vaporized fuel plate 113 is provided with the communication path 113b (by-product gas discharge port), heat transfer to the first in-cell fuel flow path 23 hardly occurs, and therefore the first in-cell fuel The excessive temperature rise of the liquid fuel existing in the flow path 23 and the accompanying crossover and temperature runaway are less likely to occur.

  (Iii) Since the by-product gas can be discharged satisfactorily from the communication path 113b, the fuel supply hindrance due to the defective discharge of the by-product gas can be suppressed, and the fuel supply to the first anode electrode 102 is favorably performed. be able to. Thereby, stable power generation characteristics can be obtained. Moreover, since by-product gas can be discharged | emitted favorably from the communication path 113b, the penetration | invasion into the 1st cell fuel flow path 23 of by-product gas can be suppressed. As a result, a sufficient amount of vaporized fuel can be stably supplied to the first anode electrode 102, so that the output stability of the fuel cell can be improved.

  The thickness of the first vaporized fuel plate 113 can be set to, for example, about 100 to 1000 μm, and the above-described effects can be sufficiently obtained even when the thickness is reduced to about 100 to 300 μm.

  The through-hole (vaporized fuel storage portion 113a) of the first vaporized fuel plate 113 is shown in FIG. 11 from the viewpoint of heat insulation between the first membrane electrode assembly 104 and the first in-cell fuel flow path 23. Thus, it is preferable to make the aperture ratio with respect to the area of the first vaporized fuel plate 113 as large as possible. Therefore, it is preferable that the first vaporized fuel plate 113 has a frame shape having a through-hole as large as possible.

  The opening ratio of the through hole, that is, the opening area of the through hole with respect to the area of the first vaporized fuel plate 113 (as will be described later, the first vaporized fuel plate 113 may have two or more through holes. Is preferably 50% or more, more preferably 60% or more. Increasing the opening ratio of the through-hole is also advantageous for enhancing the function of the vaporized fuel storage portion 113a for equalizing the concentration of fuel supplied to the first anode electrode 102, and is sufficient for the first anode electrode 102. This is also advantageous in ensuring a sufficient fuel supply. In addition, the opening rate of a through-hole is 90% or less normally.

  The communication path 113b is not limited to the groove (recessed portion) provided in the peripheral portion of the first vaporized fuel plate 113, and may be a through hole penetrating in the thickness direction. (Concave part) is preferable. From the viewpoint of the strength of the first vaporized fuel plate 113, the depth of the communication path 113b is preferably up to about 75% of the thickness of the first vaporized fuel plate 113.

  FIG. 12A is a schematic top view showing another example of the first vaporized fuel plate, and FIG. 12B is a schematic cross-sectional view taken along line XII-XII shown in FIG. As shown in FIG. 12, the first vaporized fuel plate may have two or more through holes. The first vaporized fuel plate 114 shown in FIG. 12 has a total of four through holes 114a arranged in two rows. It can also be said that beams are provided in the vertical direction and the horizontal direction of a large through hole and divided into four. Such a first vaporized fuel plate having a plurality of through-holes (provided with beams) is advantageous in that a fuel cell excellent in strength against impact or the like can be obtained because rigidity in the in-plane direction is improved. Further, in comparison with a structure without a beam as shown in FIG. 11, it is more difficult to block the through-hole due to expansion or the like due to heat of members disposed above and below the first vaporized fuel plate. Is also advantageous.

  When the first vaporized fuel plate has two or more through-holes, the number of communication paths provided at the peripheral edge thereof may be the same as the number of through-holes for each through-hole, or less than the number of through-holes. Alternatively, a large number of communication paths can be provided. In the example of FIG. 12, two communication paths 114b are provided for the four through holes 114a. In this way, it is not necessary to provide a communication path for each through-opening, but in that case, as shown in FIG. 12, the through-hole [the lower 2 in FIG. 12 (a) is not provided with the communication path 114b. The two through holes 114a] are spatially connected to the through holes [the upper two through holes 114a in FIG. 12A] provided with the communication path 114b by the connection path 114c. Similarly to the communication path 114b, the connection path 114c can be a groove (concave) provided in the beam between the through openings [FIG. 12 (b)]. By providing the connection path 114c, the by-product gas that has entered the through hole where the communication path 114b is not provided can be discharged to the outside through the communication path 114b.

  In order to improve the discharge efficiency of the by-product gas that has reached the through-hole (vaporized fuel housing portion) of the first vaporized fuel plate, or is supplied to the first anode electrode 102 of the first vaporized fuel plate. In order to enhance the function of equalizing the fuel concentration, a connection path 114d that spatially connects the through holes provided with the communication path 114b and / or the through holes not provided with the communication path 114b may be provided. It is preferable [FIG. 12 (a)].

The ratio S ₁ / S ₀ between the cross-sectional area of the communication path (the total of these cross-sectional areas when there are two or more communication paths) S ₁ and the total area S ₀ of the side surface of the first vaporized fuel plate is In order to discharge the raw gas and the heat accompanying it, it is necessary to make it larger than 0, preferably 0.002 or more. Further, it is preferably less than 0.3, more preferably less than 0.1, and still more preferably less than 0.05. When the ratio is 0.3 or more, liquid fuel leakage or air mixing is likely to occur, and power generation stability may be reduced.

For example, when all of the communication paths are provided on the side surface facing the side surface of the fuel cell to which the fuel distribution unit 10 is coupled, one or only one of the four peripheral portions of the first vaporized fuel plate has 1 or In the case where two or more communication paths are provided, the cross-sectional area of the communication path (the sum of these cross-sectional areas if there are two or more communication paths) S ₁ and the cross-sectional area S of the side surface at the peripheral edge where the communication path is provided. the ratio S ₁ / S ₂ with ₂ for the same reason as described above, preferably 0.008 or more.

  The material of the first vaporized fuel plate can be plastic, metal or non-porous carbon material. Examples of the plastic include polyphenylene sulfide (PPS), polyimide (PI), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polyvinyl chloride, polyethylene (PE), polyethylene terephthalate (PET), and polyether. Examples include ether ketone (PEEK), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF). As the metal, for example, alloys such as stainless steel and magnesium alloy can be used in addition to titanium and aluminum.

  Among the above, the first vaporized fuel plate is preferably made of a material having high rigidity such as metal, polyphenylene sulfide (PPS), or polyimide (PI). When the first vaporized fuel plate having high rigidity is used, the first vaporized fuel plate and a member adjacent to the first vaporized fuel plate can be joined by hot pressing (thermocompression bonding). Can be reduced. Further, it is possible to effectively prevent the communication path from being blocked during hot pressing.

  In addition, although a 1st vaporization fuel board may be abbreviate | omitted, in order to acquire the above-mentioned effect, it is preferable to install a 1st vaporization fuel board.

(First gas-liquid separation layer)
Directly on the first anode electrode 102 side surface of the first flow path plate 22a between the first membrane electrode assembly 104 and the first flow path plate 22a so as to cover the first in-cell fuel flow path 23. The first gas-liquid separation layer 112 to be laminated is a porous layer having a hydrophobic property of vaporization fuel permeability (property of allowing vaporization components of liquid fuel to permeate) and liquid fuel impermeability to the first anode electrode 102. It is a layer having gas-liquid separation ability that enables vaporization and supply of the fuel. When the first gas-liquid separation layer 112 is installed and one surface of the inner wall of the first in-cell fuel flow path 23 is formed from the first gas-liquid separation layer 112, the pressure of the liquid fuel in the first in-cell fuel flow path 23 Since the loss is increased, the above-described pressure loss relationship can be easily satisfied.

  The first gas-liquid separation layer 112 also has a function of controlling (limiting) the amount or concentration of the vaporized fuel supplied to the first anode electrode 102 to an appropriate amount and making it uniform. By providing the first gas-liquid separation layer 112, fuel crossover can be effectively suppressed, temperature unevenness is unlikely to occur in the first membrane electrode assembly 104, and a stable power generation state can be maintained.

  The first gas-liquid separation layer 112 is not particularly limited as long as it has gas-liquid separation ability with respect to the fuel to be used. For example, fluorine-based resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride, water repellent A porous film or a porous sheet made of a modified silicone resin, and specifically, a TEMISH (registered trademark) manufactured by Nitto Denko Corporation, which is a porous film made of polytetrafluoroethylene. ] "NTF2026A-N06" and "NTF2122A-S06".

  From the viewpoint of imparting vaporized fuel permeability and liquid fuel impermeability, the maximum pore diameter of the pores of the first gas-liquid separation layer 112 is preferably 0.1 to 10 μm, preferably 0.5 to 5 μm. More preferably. The maximum pore diameter can be determined by measuring the bubble point (JIS K 3832) using methanol or the like. The first gas-liquid separation layer 112 has a contact angle with water, which will be described later, of usually 80 degrees or more, and more typically 90 degrees or more.

  The thickness of the first gas-liquid separation layer 112 is not particularly limited, but is preferably 20 μm or more and more preferably 50 μm or more in order to sufficiently express the above function. Further, from the viewpoint of reducing the thickness of the fuel cell, the thickness of the first gas-liquid separation layer 112 is preferably 500 μm or less, and more preferably 300 μm or less.

(First cathode moisturizing layer and first anode moisturizing layer)
The first cathode moisturizing layer 108 is disposed on the first cathode electrode 103, preferably on the first cathode current collecting layer 106, and water generated at the first cathode electrode 103 is formed from the first cathode electrode 103 side to the fuel cell. This is an optional layer for preventing evaporation from the cell. By providing the first cathode moisturizing layer 108, water generated at the first cathode electrode 103 is efficiently returned to the first anode electrode 102 via the first electrolyte membrane 101 without evaporating outside the fuel cell, It can be used effectively for the reaction at the first anode electrode 102.

  The first anode moisturizing layer 107 is disposed between the first anode electrode 102 or the first anode current collecting layer 105 and the vaporized fuel storage portion 113a. This is an optional layer for preventing evaporation from the side to the outside of the first membrane electrode assembly (for example, to the vaporized fuel housing portion 113 a) and for holding it within the first anode electrode 102. By providing the first anode moisturizing layer 107, the water generated at the first cathode electrode 103 and reaching the first anode electrode 102 via the first electrolyte membrane 101 is not evaporated to the outside of the first membrane electrode assembly. It can be satisfactorily held in one anode electrode 102. As a result, the water is effectively used for the reaction at the first anode electrode 102, so that the reaction efficiency at the first anode electrode 102 is improved and high power generation characteristics can be stably exhibited. In particular, the combined use with the first cathode moisturizing layer 108 can achieve the effect more effectively.

  Further, the installation of the first cathode moisturizing layer 108 and the first anode moisturizing layer 107 is also effective in preventing the drying of the first electrolyte membrane 101 and the accompanying increase in cell resistance and power generation characteristics.

  The first cathode moisturizing layer 108 and the first anode moisturizing layer 107 are gas permeable so as to be able to permeate vaporized fuel or an oxidant (such as air) from the outside of the fuel cell, are insoluble in water, And it is comprised from the material which has moisture retention (property which does not evaporate water). Specifically, fluorine resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); acrylic resins; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate; polyurethane resins Polyamide resin; Polyacetal resin; Polycarbonate resin; Chlorine resin such as polyvinyl chloride; Polyether resin; Polyphenylene resin; Porous membrane (porous layer) made of water repellent treated silicone resin, etc. Can be. These moisturizing layers can be foams made of the above polymer, fiber bundles, woven fibers, non-woven fibers, or combinations thereof.

  The first cathode moisturizing layer 108 is desired to be gas permeable so as to allow the passage of an oxidant (air, etc.) from the outside of the fuel cell and to have moisture retention (a property that does not evaporate water). Therefore, the porosity is preferably 30% or more and 90% or less, and more preferably 50% or more and 80% or less. When the porosity exceeds 90%, it may be difficult to retain water generated at the first cathode electrode 103 in the fuel cell. On the other hand, when the porosity is less than 30%, the diffusion of the oxidant (such as air) from the outside of the fuel cell is hindered, and the power generation characteristics in the first cathode electrode 103 are likely to deteriorate.

The first anode moisturizing layer 107 is gas permeable so as to allow the by-product gas (such as CO ₂ gas) generated in the vaporized fuel and the catalyst layer to pass therethrough, and has a moisturizing property (a property that does not evaporate water). Therefore, the porosity is preferably 50% or more and 90% or less, and more preferably 60% or more and 80% or less. When the porosity exceeds 90%, it is difficult to retain water generated in the first cathode electrode 103 and reaching the first anode electrode 102 via the first electrolyte membrane 101 in the first membrane electrode assembly 104. Can be. On the other hand, when the porosity is less than 50%, diffusion of vaporized fuel and by-product gas (CO ₂ gas or the like) generated in the catalyst layer is hindered, and the power generation characteristics in the first anode electrode 102 are likely to deteriorate.

The porosity of the first cathode moisturizing layer 108 and the first anode moisturizing layer 107 is determined by measuring the volume and weight of the moisturizing layer to determine the specific gravity of the moisturizing layer.
Porosity (%) = [1- (specific gravity of moisture retaining layer / material specific gravity)] × 100
Can be calculated.

  The thicknesses of the first cathode moisturizing layer 108 and the first anode moisturizing layer 107 are not particularly limited, but are preferably 20 μm or more, and more preferably 50 μm or more in order to sufficiently exhibit the above functions. Further, from the viewpoint of reducing the thickness of the fuel cell, it is preferably 500 μm or less, and more preferably 300 μm or less.

  It is desirable that the first cathode moisture retention layer 108 and the first anode moisture retention layer 107 have high water absorption properties and do not have the property of taking in liquid water once absorbed and not releasing it to the outside. Therefore, it is preferable to have water repellency. From this point of view, these moisturizing layers are, among the above, a porous film made of a fluorine-based resin such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a water-repellent treated silicone resin. (Porous layer) is preferable. Specifically, “NTF2026A-N06” and “NTF2122A-S06” manufactured by Nitto Denko Co., Ltd. [TEMISH (registered trademark)], which are porous films made of polytetrafluoroethylene, can be exemplified.

  The first anode moisturizing layer 107 has a first anode current collecting layer 105 disposed on the first anode electrode 102 and is laminated on the first anode current collecting layer 105 so as to be in contact with the first anode current collecting layer 105. It is preferable. Thereby, it is possible to more effectively prevent moisture in the first anode electrode 102 from being evaporated to the outside of the first membrane electrode assembly 104.

  The first cathode moisturizing layer 108 and the first anode moisturizing layer 107 are provided as necessary, and at least one of them may be omitted.

(Fuel cell type)
The first fuel cell 20 (and the second fuel cell 20 ′, and hence the fuel cell stack and the fuel cell stack composite of the present invention) may be a polymer electrolyte fuel cell or a direct alcohol fuel cell. In particular, it is suitable as a direct alcohol fuel cell (in particular, a direct methanol fuel cell). Examples of the liquid fuel include alcohols such as methanol and ethanol; acetals such as dimethoxymethane; carboxylic acids such as formic acid; esters such as methyl formate; and aqueous solutions thereof. The liquid fuel is not limited to one type, and may be a mixture of two or more types. In view of low cost, high energy density per volume, high power generation efficiency, etc., an aqueous methanol solution or pure methanol is preferably used. In addition, as the oxidant gas supplied to the first cathode electrode, air or oxygen gas is preferable, and air is particularly preferable.

[4] Second Fuel Battery Cell The second fuel battery cell 20 ′ has a second anode electrode, a second electrolyte membrane, and a second cathode electrode in this order, for example, like the first fuel battery cell 20. A membrane electrode composite; a second anode current collecting layer laminated on and electrically connected to the second anode electrode; a second cathode current collecting layer laminated on and electrically connected to the second cathode electrode A second anode moisturizing layer laminated on the second anode current collecting layer so as to be in contact with the second anode current collecting layer; a second layer laminated on the second cathode current collecting layer so as to be in contact with the second cathode current collecting layer; 2 cathode moisturizing layer; a second flow path plate disposed on the second anode electrode side and having a second in-cell fuel flow path 23 ′ for flowing liquid fuel (diffusing and flowing in the fuel cell surface); A second cell between the two-membrane electrode assembly and the second flow path plate; A second gas-liquid separation layer that is disposed on the surface of the second flow path plate so as to cover the fuel flow path 23 ′ and is capable of permeating the vaporized component of the liquid fuel; and the second gas-liquid separation layer and the second anode moisturizing It can be comprised from the 2nd vaporization fuel board which is arrange | positioned between layers and comprises the vaporization fuel accommodating part.

  In this example, the second power generation unit 21 ′ includes a second cathode moisturizing layer, a second cathode current collecting layer, a second membrane electrode composite, a second anode current collecting layer, and a second anode moisturizing layer, and a second fuel supply The part 22 ′ includes a second vaporized fuel plate, a second gas-liquid separation layer, and a second flow path plate.

  For the details of the members constituting the second fuel cell 20 ′, the description of the corresponding members constituting the first fuel cell 20 is cited. The layer configuration of the second fuel battery cell 20 ′ may be the same as or different from that of the first fuel battery cell 20. The description of the first fuel cell 20 is also cited for the type of the fuel cell.

[5] Fuel Distribution Unit As described above, the fuel distribution unit 10 includes the introduction port 11 for introducing the liquid fuel, and the in-cell fuel flow paths 23, 23 of the introduction port 11 and the respective fuel cells 20, 20 ′. It is a member independent of the fuel cells for distributing and supplying the liquid fuel to the fuel cells 20 and 20 ′. In the example of FIG. 1, the number of inlets 11 is one, but is not limited to this, and the fuel distributor 10 may include a plurality of inlets 11 (for example, 4 shown in FIG. 2). When one fuel cell is set as one set, one inlet is provided per set).

  The outer shape of the fuel distribution unit 10 is not particularly limited, and is an appropriate shape in consideration of the shape and area of the fuel cell housing space of the applied electronic device, the number and arrangement of the fuel cells incorporated in the fuel cell stack, and the like. It is said. The fuel distribution unit 10 can be made of various plastic materials, metal materials, alloy materials, and the like.

  Each fuel cell 20, 20 ′ and the fuel distributor 10 sandwich packing (such as double-sided tape) between these contact portions as necessary, and use fastening members such as screws, bolts and nuts. Can be combined.

[6] Modified Example The fuel cell stack of the present invention includes the following modified example in addition to the embodiment and the modified example described above.

  (I) The number of fuel cells included in the fuel cell stack is not particularly limited, and includes at least one first fuel cell 20 and one second fuel cell arranged on the main surface of the first fuel cell 20. The fuel cell 20 ′ (that is, at least two fuel cells stacked in the thickness direction) may be included.

  (Ii) When the fuel cell stack includes a fuel cell assembly composed of two or more fuel cells arranged on the same plane, the two or more fuel cells need to be arranged in a line. There is no. However, in order to improve the integration rate of the fuel cells, reduce the area occupied by the fuel cell stack, simplify the structure of the fuel distribution unit, and secure a supply path for straight oxidizer (air, etc.), they are arranged in a line. It is preferable.

  (Iii) The second fuel battery cell 20 ′ disposed on the main surface of the first fuel battery cell 20 does not necessarily have to be disposed directly above (opposed to) the first fuel battery cell 20. From the standpoint of reducing the area occupied by the fuel cell stack, it is preferable that the fuel cell stacks are arranged to face each other.

  (Iv) The first fuel cells 20 and the second fuel cells 20 ′ disposed on the main surface (disposed opposite to each other) are, as shown in FIGS. The cathode electrode side of one of the fuel cells and the fuel supply side of the other fuel cell may be opposed to each other, that is, the first cathode electrode side and the first cathode electrode side. The two fuel supply units may be arranged so as to face each other, or the second cathode electrode side and the first fuel supply unit side may be arranged so as to face each other.

  When the cathode electrode sides are arranged to face each other, the thickness of the thickest part of the fuel cell stack can be further reduced, and the oxidizing agent supply path for the first fuel cell 20 and the oxidation for the second fuel cell 20 ′. There is an advantage that the agent supply path can be shared (that is, the oxidant supply path in which the space 30 in FIG. 2 and the like is shared).

  (V) The distance (the width of the space 30) between the first fuel cell 20 and the second fuel cell 20 ′ disposed on the main surface of the first fuel cell 20 is not particularly limited. Considering the oxidant supply efficiency to the cathode electrode of the battery cell, it is preferably 0.5 to 5.0 mm.

  (Vi) When the fuel cell stack includes two or more fuel cells arranged in a line on the same plane, these fuel cells have gaps between adjacent fuel cells as shown in FIG. It may be arranged so as to be formed, or may be arranged without a gap as shown in FIG. The former configuration (configuration shown in FIG. 1) uses, for example, air as an oxidant, and when the air around the fuel cell stack is taken in by natural convection without using an auxiliary machine such as a fan or blower for blowing. This is advantageous because air can be taken in from the gap. Further, the latter configuration (configuration of FIG. 13) is advantageous because when the oxidant such as air is sent from the side surface of the fuel cell stack using the above-mentioned auxiliary device, the oxidant can be surely flowed into the space 30. is there.

<Fuel cell stack composite>
In the present invention, the “fuel cell stack composite” includes a first fuel cell stack and a second fuel cell stack disposed on the main surface, in other words, a plurality of fuel cell stacks. It is laminated in the thickness direction. The fuel cell stack composite may include three or more fuel cell stacks.

  As the first and second fuel cell stacks, the fuel cell stack according to the present invention described above is used. The first fuel cell stack and the second fuel cell stack may be stacked in contact with each other, or may be arranged with a space (separated).

  FIG. 14 is a schematic perspective view showing an example of a fuel cell stack composite according to the present invention. The fuel cell stack composite 6 shown in FIG. 14 includes a first fuel cell stack 1a and a second fuel cell stack 1b stacked in contact with the main surface. Both the first and second fuel cell stacks 1a and 1b have the same fuel flow path structure as in FIG. 3 (reference numerals 10 ′, 11 ′, 16 ′ to 18 ′, 19a ′ and 19b ′ are 10, 11, 16 to 18, 19 a and 19 b), but in the fuel distributor 10 ′ of the second fuel cell stack 1 b, the first main channel 16 ′ is the first fuel cell stack 1 a. The out-cell fuel flow path 15 of the first fuel cell stack 1a and the out-cell fuel flow path 15 ′ of the second fuel cell stack 1b communicate with each other. Thereby, the fuel can be supplied to all the fuel cells of the fuel cell stack composite by supplying the liquid fuel from the introduction port 11 ′.

  As described above, when a plurality of fuel cell stacks are stacked in the thickness direction, the fuel flow outside the cell of the upper fuel cell stack (second fuel cell stack 1b) is connected at the connection portion of the fuel flow paths outside the cells. The cross-sectional area of the channel (external cell fuel flow path 15 ') is made larger than the cross-sectional area of the out-cell fuel flow path (external cell fuel flow path 15) of the lower fuel cell stack (first fuel cell stack 1a). Is preferred. Thereby, not only the fuel supply to the first fuel cell 20 and the second fuel cell 20 ′ disposed opposite to each other in each fuel cell stack obtained by satisfying the above-described pressure loss relationship is made uniform. Since uniform fuel supply to the first fuel cell stack 1a and the second fuel cell stack 1b is possible, uniform fuel supply to all the fuel cells of the fuel cell stack composite is possible.

  The fuel flow path structure shown in FIG. 14 is an example, and as described above, various shapes can be adopted as long as a predetermined pressure loss relationship is satisfied (for example, the shape shown in FIG. 2, FIG. 4, or FIG. 6). Such).

  Further, when the first fuel cell stack 1a and the second fuel cell stack 1b are stacked in contact with each other, the adjacent first fuel supply unit 22 and second fuel supply unit 22 ′ are integrated into one member. It can also be configured. At this time, the integrated fuel supply section may have both the first in-cell fuel flow path 23 and the second in-cell fuel flow path 23 ′, or the third fuel supply section 23 shown in FIG. Like the fuel cell 20 ″, the first in-cell fuel flow path 23 and the second in-cell fuel flow path 23 ′ may be integrated to have only one out-cell fuel flow path. In particular, the latter case is advantageous for reducing the thickness of the fuel cell stack composite.

<Fuel cell system>
The fuel cell stack and the fuel cell stack composite according to the present invention can be provided with a fuel tank for storing a liquid fuel to form a fuel cell system. 16 and 17 are a schematic perspective view and a schematic cross-sectional view, respectively, showing an example of the fuel cell system.

  A fuel cell system 5 shown in FIGS. 16 and 17 includes the above-described fuel cell stack 1 according to the present invention and a liquid feeding unit (liquid feeding unit) 2 for feeding liquid fuel to the fuel cell stack 1. The liquid feeding unit 2 is connected to at least the introduction port 11 of the fuel distribution unit 10 included in the fuel cell stack 1 and includes a fuel tank 2a that stores liquid fuel. 11 includes a liquid feeding means 2b such as a liquid feeding pump that promotes the flow of the liquid fuel to 11. When the liquid feeding means 2b is included, for example, the liquid feeding unit 2 connects the fuel tank 2a and the liquid feeding means 2b with the first liquid feeding path 3, and the liquid feeding means 2b and the inlet 11 of the fuel distributor 10 are connected to each other. Can be configured to be connected by the second liquid feeding path 4.

  When the fuel cell stack composite, for example, the fuel cell stack composite 6 of FIG. 14 is used instead of the fuel cell stack 1, the fuel tank 2a (or the second liquid feed) is introduced into the inlet 11 ′ of the second fuel cell stack 1b. Road 4) is connected.

  The fuel cell stack, the fuel cell stack composite and the fuel cell system of the present invention are suitable as a power source for electronic devices, in particular, small electronic devices such as mobile devices typified by mobile phones, electronic notebooks and notebook computers. Can be used.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

<Example 1>
The fuel cell stack having the configuration shown in FIG. 1 and a fuel cell system using the fuel cell stack were manufactured by the following procedure. The structure of the fuel flow path of the fuel cell stack is as shown in FIG. 2, and the layer structure of the first and second fuel cells 20, 20 ′ is as shown in FIG.

(1) Production of Membrane Electrode Composite Catalyst-supported carbon particles (TEC66E50, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 32.5% by weight and a Ru loading amount of 16.9% by weight, and 20% by weight of Nafion as an electrolyte ( (Registered trademark) Alcohol solution (Aldrich), n-propanol, isopropanol, and zirconia balls are put into a fluororesin container at a predetermined ratio and mixed for 50 minutes at 500 rpm using a stirrer. As a result, a catalyst paste for the anode electrode was produced. A catalyst paste for the cathode electrode was prepared in the same manner as the catalyst paste for the anode electrode, except that catalyst-supporting carbon particles (TEC10E50E, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 46.8% by weight were used.

Next, after cutting carbon paper (25BC, manufactured by SGL) having a water-repellent porous layer on one side into a length of 35 mm and a width of 40 mm, the above-mentioned catalyst paste for anode electrode is formed on the porous layer. Is applied using a screen printing plate having a window with a length of 30 mm and a width of 35 mm so that the amount of the catalyst supported is about 3 mg / cm ^2, and then dried, so that the anode conductive porous layer is coated on the carbon paper. An anode electrode having an anode catalyst layer formed in the center and having a thickness of about 300 μm was produced. Further, a screen printing plate having a window of 30 mm length and 35 mm width on the porous layer of carbon paper of the same size so that the catalyst loading amount of the above cathode electrode is about 1 mg / cm ^2. The cathode electrode having a thickness of about 270 μm in which the cathode catalyst layer was formed at the center on the carbon paper, which is the cathode conductive porous layer, was produced.

  Next, a perfluorosulfonic acid ion exchange membrane (Nafion (registered trademark) 117, manufactured by DuPont) having a thickness of about 175 μm is cut into a length of 35 mm and a width of 40 mm to form an electrolyte membrane, and the anode electrode, the electrolyte membrane, and the cathode The electrodes were stacked in this order so that the respective catalyst layers faced the electrolyte membrane, and then subjected to thermocompression bonding at 130 ° C. for 2 minutes to join the anode and cathode electrodes to the electrolyte membrane. The superposition was performed so that the positions of the anode electrode and the cathode electrode in the plane of the electrolyte membrane coincided and the centers of the anode electrode, the electrolyte membrane, and the cathode electrode coincided. Next, the outer peripheral portion of the obtained laminate was cut to produce a membrane electrode assembly (MEA) having a length of 22 mm and a width of 26 mm.

(2) Lamination of current collecting layer A stainless steel plate (NSS445M2, manufactured by Nisshin Steel Co., Ltd.) having a length of 26.5 mm, a width of 27 mm, and a thickness of 0.1 mm is prepared. Two stainless steel plates with multiple through holes penetrating in the thickness direction are produced by processing holes (opening pattern: staggered 60 ° pitch 0.8 mm) from both sides by wet etching using a photoresist mask. These were used as the anode current collecting layer and the cathode current collecting layer.

  Next, the anode current collecting layer is laminated on the anode electrode via a conductive adhesive layer made of carbon particles and an epoxy resin, and the cathode current collecting layer is arranged on the cathode electrode via the same conductive adhesive layer. These were joined together by thermocompression bonding to produce a MEA-current collecting layer laminate.

(3) Moisturizing layer bonding As an anode moisturizing layer and a cathode moisturizing layer, a porous film made of polytetrafluoroethylene (“TEMISH (registered trademark) NTF2122A-S06” manufactured by Nitto Denko Corporation, length: 22 mm, Two sheets having a width of 26 mm, a thickness of 0.2 mm, and a porosity of 75% were prepared. These moisturizing layers were laminated on the anode current collecting layer and the cathode current collecting layer of the MEA-current collecting layer laminate through an adhesive layer made of polyolefin, and these were joined by thermocompression bonding. These moisturizing layers were joined so as to be disposed immediately above or below the MEA.

(4) Joining of vaporized fuel plate and gas-liquid separation layer A vaporized fuel plate made of SUS having a shape shown in FIG. 12 having a length of 26.5 mm, a width of 27 mm, and a thickness of 0.2 mm was produced by etching (communication). All paths and connection paths consist of grooves (recesses). The opening ratio of the through holes is 63% in total, and the ratio of the total of the two cross-sectional areas of the communication path and the total area of the side surfaces of the vaporized fuel plate is 0.04. A gas-liquid separation layer was laminated on the surface of the vaporized fuel plate opposite to the groove forming surface, and these were joined by thermocompression bonding. As the gas-liquid separation layer, a porous film made of polytetrafluoroethylene having a length of 26.5 mm, a width of 27 mm, and a thickness of 0.2 mm ("TEMish (registered trademark) NTF2122A-S06" manufactured by Nitto Denko Corporation) ) Was used. The contact angle of this porous film with respect to water was about 120 degrees. The bubble point of this porous film based on JIS K3832 was 18 kPa when the measurement medium was methanol.

(5) Joining of the flow path plates 26.5 mm in length, 27 mm in width with the in-cell fuel flow path (flow path width: 0.5 mm, depth: 0.4 mm) having the flow path pattern as shown in FIG. A flow path plate made of SUS having a thickness of 0.6 mm was prepared. After laminating the flow path plate on the gas-liquid separation layer of the vaporized fuel plate / gas-liquid separation layer assembly via a polyolefin-based adhesive, the bonded body and the flow path plate are joined by thermocompression bonding. did.

(6) Production of fuel cell The MEA-current collecting layer laminate having the moisturizing layer produced above was laminated on the vaporized fuel plate, and these were joined by thermocompression bonding. Finally, an epoxy resin was applied to the end face and cured to form a sealing layer to obtain a fuel cell. A total of 20 fuel cells were produced.

(7) Fabrication of fuel distribution part The outer shape of polyphenylene sulfide (PPS) is as shown in FIGS. 1 and 2 (outer length is 10 mm, width is 138 mm, height is 6.0 mm), and is shown in FIG. Such an out-cell fuel channel (one first main channel, a total of ten second main channels 17, a third main channel, a total of ten first branch channels 19a and a total of ten first channels). A fuel distribution part having a bifurcated flow path 19b) and having one inlet at the center in the longitudinal direction of the upper surface was produced. The flow width of the fuel flow path outside the cell is 1.0 mm, and the depth is 1.0 mm.

(8) Fabrication of fuel cell stack Twenty fuel cells and the fuel distributor were joined in the arrangement relationship shown in FIGS. 1 and 2. In order to prevent liquid leakage at the connection between the fuel flow path inside the cell and the fuel flow path outside the cell, a double-sided tape is placed between the fuel cell and the fuel distribution part, and then tightened with screws. I did it.

(9) Fabrication of fuel cell system A fuel tank and a liquid pump (micropump) are connected by a polyether ether ketone (PEEK) pipe, and the fuel distributor is provided in the liquid cell pump and the fuel cell stack obtained above. The fuel cell system was manufactured by connecting the inlet of the above with a pipe made of polyetheretherketone (PEEK).

<Comparative Example 1>
Fuel cell stack in the same manner as in Example 1 except that the flow width and depth of the fuel flow path outside the cell (flow path width 1.0 mm, depth 1.0 mm) are the same as the fuel flow path in the cell. And a fuel cell system was fabricated.

(Evaluation of power generation characteristics)
For the fuel cell stacks of Example 1 and Comparative Example 1, a 10 mol / L aqueous methanol solution was filled in a fuel tank, supplied to the inlet using a liquid feed pump, and power generation by the fuel cell stack was started. For each battery cell, the voltage change (IV characteristic) for each fuel cell when a load current of 10 mA / cm ² per minute was increased stepwise was measured. The results are shown in FIG. 18 (Example 1) and FIG. 19 (Comparative Example 1). It should be noted that 10 of the first fuel cells (disposed on the lower side in the direction of gravity in the fuel cell system) are cells 1-A, 1-B, 1-C, 1-D, 1-E, 1-F, 1- G, 1-H, 1-I, 1-J, and 10 of the second fuel cells (arranged on the upper side in the direction of gravity in the fuel cell system) are cells 2-A, 2-B, 2-C, 2- D, 2-E, 2-F, 2-G, 2-H, 2-I, 2-J.

  In Example 1, the first fuel cell and the second fuel cell exhibited substantially the same IV characteristics. This is because in Example 1 compared to Comparative Example 1, the flow width and depth of the in-cell fuel flow path are small, causing pressure loss, so that all of the out-cell fuel flow path is filled with liquid fuel. This is because the liquid fuel is supplied to each in-cell fuel flow path at a uniform flow rate later.

  On the other hand, in the first comparative example, the IV characteristic of the second fuel cell has a phenomenon that the voltage decreases at a lower current density than the first fuel cell (substance supply rate limiting due to insufficient fuel supply). It was. Further, it was recognized that the IV characteristics between the first fuel cell and the second fuel cell greatly vary. For this reason, in the comparative example 1, the characteristic of the original fuel cell cannot be extracted, and the output of the whole fuel cell system is reduced.

  The phenomenon in which the IV characteristics differ greatly between the fuel cells as in Comparative Example 1 is a serious problem particularly when the first fuel cell and the second fuel cell are electrically connected in series. In the series circuit, since the same amount of current flows through the first fuel cell and the second fuel cell, the amount of current in the circuit is determined by the amount of current that can flow through the second fuel cell having the lowest performance. . For this reason, even the first fuel battery cell having originally good potential cannot be generated with sufficiently high output.

  DESCRIPTION OF SYMBOLS 1 Fuel cell stack, 1a 1st fuel cell stack, 1b 2nd fuel cell stack, 2 liquid feeding unit, 2a fuel tank, 2b liquid feeding means, 1st liquid feeding path, 4 2nd liquid feeding path, 5 fuel cell System, 6 Fuel cell stack composite, 10, 10 'Fuel distribution part, 11, 11' Inlet, 15, 15 'Out-cell fuel flow path, 16, 16' First main flow path, 16A End, 17, 17 'Second main flow path, 17A end, 18, 18' Main flow path, 19a, 19a 'First branch flow path, 19b, 19b' Second branch flow path, 20 First fuel cell, 20 'Second fuel cell Cell, 20 ″ third fuel cell, 21 first power generation unit, 21 ′ second power generation unit, 22 first fuel supply unit, 22a first flow path plate, 22 ′ second fuel supply unit, 23 first cell Inner fuel flow path, 23 'Second cell fuel Path, 30 space (oxidant path), 40 first fuel cell assembly, 50 second fuel cell assembly, 60 porous body, 101 first electrolyte membrane, 102 first anode electrode, 103 first cathode electrode 104 First membrane electrode assembly, 105 First anode current collection layer, 106 First cathode current collection layer, 107 First anode moisture retention layer, 108 First cathode moisture retention layer, 112 First gas-liquid separation layer, 113, 114 1st vaporization fuel board, 113a, 114a Vaporization fuel accommodating part (through port), 113b, 114b Communication path, 114c, 114d Connection path.

Claims (17)

A first membrane electrode assembly having a first anode electrode, a first electrolyte membrane, and a first cathode electrode in this order; and a first in-cell fuel flow channel for circulating liquid fuel; A first fuel battery cell including a first fuel supply unit disposed on the pole side;
A fuel cell disposed on the main surface of the first fuel cell, a second membrane electrode assembly having a second anode electrode, a second electrolyte membrane and a second cathode electrode in this order, and a liquid A second fuel battery cell having a second fuel supply section disposed on the second anode electrode side, having a fuel flow path in the second cell for circulating fuel;
A fuel distributor coupled to the first and second fuel cells and for distributing the liquid fuel to the first and second fuel cells,
The fuel distributor has an inlet for introducing the liquid fuel, and an out-cell fuel flow path connecting the inlet and the first and second in-cell fuel flow paths,
A fuel flow path composed of the first and second in-cell fuel flow paths and the out-cell fuel flow path is a connection portion between the first and second in-cell fuel flow paths and the out-cell fuel flow path or the A fuel cell stack configured to increase the pressure loss of liquid fuel flowing from the introduction port to the first and second in-cell fuel flow paths from the introduction port through the outside-cell fuel flow path at a boundary.   At least in the connection portion between the first and second in-cell fuel flow passages and the out-cell fuel flow passage or in the vicinity thereof, the cross-sectional area of the fuel flow passage portion on the inlet side is based on the connection portion or the vicinity thereof. 2. The fuel cell stack according to claim 1, wherein the fuel cell stack is larger than the cross-sectional area of the other fuel flow path portion.   At least in a connection portion between the first and second in-cell fuel flow paths and the out-cell fuel flow path, a cross-sectional area of the out-cell fuel flow path is equal to a cross-sectional area of the first and second in-cell fuel flow paths. The fuel cell stack according to claim 2, which is larger than 3.   4. The fuel cell according to claim 2, wherein a porous body is filled in the fuel flow path at or near the connection portion between the first and second in-cell fuel flow paths and the out-cell fuel flow path. stack. The out-cell fuel flow path includes a main flow path connected to the introduction port, and a first branch flow path that connects the end of the main flow path opposite to the introduction port and the first in-cell fuel flow path. And a second branch flow path connecting the end and the second in-cell fuel flow path,
The fuel cell stack according to any one of claims 1 to 4, wherein the first and second branch flow paths include a flow path portion extending in a direction substantially perpendicular to a main surface of the first or second fuel battery cell. .   The first branch flow path and the first in-cell fuel flow path form a flow path extending in a substantially vertical direction with respect to a main surface of the first fuel battery cell at a connection portion thereof. The bifurcated flow path and the fuel flow path in the second cell form a flow path extending in a substantially vertical direction with respect to the main surface of the second fuel cell at the connection portion. Fuel cell stack.   The first branch flow path and the first in-cell fuel flow path form a flow path extending substantially parallel to the main surface of the first fuel cell at the connection portion thereof, and the second 6. The fuel according to claim 5, wherein the branch flow path and the fuel flow path in the second cell form a flow path extending substantially parallel to the main surface of the second fuel battery cell at a connection portion thereof. Battery stack.   The said 1st fuel cell and the said 2nd fuel cell are any one of Claims 1-7 arrange | positioned so that the said 1st cathode pole side and the said 2nd cathode pole side may oppose. The fuel cell stack described in 1.   The first fuel cell and the second fuel cell are arranged such that the first cathode electrode side and the second fuel supply unit side are opposed to each other, or the second cathode electrode side and the first fuel cell. The fuel cell stack according to any one of claims 1 to 7, wherein the fuel cell stack is disposed so as to be opposed to the supply unit side. A first fuel cell assembly comprising two or more first fuel cells arranged on the same plane;
Two or more fuel cell assemblies arranged on a main surface of the first fuel cell assembly, arranged on the same plane, and arranged opposite to each of the first fuel cells. A second fuel cell assembly comprising second fuel cells;
The fuel distributor coupled to all the first and second fuel cells;
The fuel cell stack according to claim 1, comprising:   The first fuel cell assembly is composed of two or more first fuel cells arranged in a line, and the second fuel cell assembly is composed of two or more second fuel cells arranged in a line. The fuel cell stack according to claim 10.   In the first fuel cell assembly, the two or more first fuel cells are arranged such that a gap is formed between two adjacent first fuel cells, and the second fuel cell The fuel cell stack according to claim 11, wherein in the assembly, the two or more second fuel cells are arranged such that a gap is formed between two adjacent second fuel cells.   The first fuel cell assembly includes two or more first fuel cells arranged in a line without a gap, and the second fuel cell assembly includes two or more second fuel cells. The fuel cell stack according to claim 11, wherein the fuel cell stack is arranged in a line.   The fuel cell stack according to any one of claims 1 to 13, which is a direct alcohol fuel cell. A first fuel cell stack that is the fuel cell stack according to any one of claims 1 to 14,
The second fuel cell stack, which is the fuel cell stack according to any one of claims 1 to 14, disposed on a main surface of the first fuel cell stack;
A fuel cell stack composite comprising:
The fuel flow path outside the cell of the first fuel cell stack and the fuel flow path outside the cell of the second fuel cell stack are in communication with each other,
A fuel cell stack in which the cross-sectional area of the fuel flow path outside the cell of the second fuel cell stack is larger than the cross-sectional area of the fuel flow path outside the cell of the first fuel cell stack at least at the connection portion of the fuel flow paths outside the cell. Complex. The fuel cell stack according to any one of claims 1 to 14 or the fuel cell stack composite according to claim 15;
A fuel tank for containing the liquid fuel connected to the fuel cell stack or the fuel cell stack complex;
Including fuel cell system.   The fuel cell system according to claim 16, further comprising a liquid feeding unit that promotes the flow of the liquid fuel from the fuel tank to the fuel cell stack or the fuel cell stack composite.

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