WO2013018502A1

WO2013018502A1 - Fuel cell

Info

Publication number: WO2013018502A1
Application number: PCT/JP2012/067308
Authority: WO
Inventors: 武範大西; 智寿吉江; 宏隆水畑; 菰田　睦子; 忍竹中; 将史村岡
Original assignee: シャープ株式会社
Priority date: 2011-08-03
Filing date: 2012-07-06
Publication date: 2013-02-07
Also published as: JP2013033690A

Abstract

Provided is a fuel cell that includes one or more first fuel cells and one or more second fuel cells disposed on the same plane. The first fuel cell is equipped with a first composite film electrode, a first flow channel plate having a first cell internal flow channel through which flows a liquid fuel, a first vapor-liquid separation layer permeable to the vaporized component of the liquid fuel and disposed between the first composite film electrode and the first flow channel plate, and a first intervening layer disposed so as to cover the first cell internal flow channel. The second fuel cell is equipped with a second composite film electrode, a second flow channel plate having a second cell internal flow channel through which flows a liquid fuel, and a second vapor-liquid separation layer permeable to the vaporized component of the liquid fuel and disposed so as to cover the second cell internal flow channel.

Description

Fuel cell

The present invention relates to a fuel cell in which a plurality of fuel cells are arranged on the same plane.

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.

The direct alcohol fuel cell that uses alcohol or an aqueous alcohol solution as the fuel has a simplified structure of the fuel cell because the fuel storage chamber can be designed relatively easily compared to the case where the fuel is a gas. Space-saving is possible, and the expectation as a small fuel cell for the purpose of application to portable electronic devices is particularly high.

In a fuel cell, a plurality of fuel cells are electrically connected and combined (stack) in order to increase the power, which is insufficient with one fuel cell, to a sufficient level as a new power source for portable electronic devices. Etc.) are conventionally performed. An example is a fuel in which a plurality of fuel cells are arranged on the same plane as described in, for example, Japanese Patent Application Laid-Open No. 2004-079506 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2006-093119 (Patent Document 2). A battery (hereinafter also referred to as a “planar integrated fuel cell”).

Japanese Patent Laid-Open No. 2004-079506 JP 2006-093119 A

Assuming that a planar integrated fuel cell is applied as a power source for an electronic device such as a portable electronic device, in accordance with the shape and area of the limited fuel cell accommodation space in various electronic devices that can be applied, It is extremely meaningful to be able to flexibly design a planar integrated fuel cell structure. This is because it greatly contributes to improvement of production efficiency (simplification of production process) and reduction of production cost of the fuel cell.

Generally, the conventional planar integrated fuel cell as described in

Patent Documents

1 and 2 has a structure in which a plurality of fuel cells share one fuel supply unit. Here, the fuel supply unit refers to a part that contains or distributes the fuel supplied to each fuel cell, and includes the liquid fuel storage unit 3 in Patent Document 1 and the bipolar plate 20 in Patent Document 2. Equivalent to. However, in the case of such a structure, in order to apply to an electronic device having a different shape and area of the fuel cell accommodation space, it is not necessary to change only the design of the fuel cell cell integration form. Therefore, it is necessary to redesign the system, and it is not easy to change the design of the fuel cell structure according to the electronic equipment, which is disadvantageous in terms of production efficiency and production cost of the fuel cell.

The solution of the above problem proposed by the present inventors is to modularize the fuel cell by providing a fuel flow path through which fuel flows to each fuel cell itself. According to this, without changing the design of the module (fuel cell having the fuel flow path), the number of modules, the arrangement pattern, and the fuel for guiding the fuel to the fuel flow path of each fuel battery cell as required By redesigning only the supply system, the planar integrated fuel cell can be easily applied to electronic devices having different shapes and areas of the fuel cell accommodation space. However, when a planar integrated fuel cell is constructed using modularized fuel cells, it may be difficult to uniformly supply fuel to each fuel cell.

An object of the present invention is to provide a fuel cell in which a plurality of modularized fuel cells having fuel flow paths are arranged on the same plane, and a fuel cell with good uniformity of fuel supply to each fuel cell. There is to do.

The present invention includes the following.
[1] A fuel cell including one or more first fuel cells and one or more second fuel cells arranged on the same plane,
The first fuel battery cell is
A first membrane electrode assembly having a first anode electrode, a first electrolyte membrane, and a first cathode electrode in this order;
A first flow path plate disposed on the first anode electrode side, wherein a first in-cell fuel flow path for circulating liquid fuel is disposed on the first anode electrode side surface;
A first gas-liquid separation layer disposed between the first membrane electrode assembly and the first flow path plate and capable of transmitting a vaporized component of the liquid fuel;
A first intervening layer disposed between the first gas-liquid separation layer and the first flow path plate so as to cover the first in-cell fuel flow path, and having a contact angle with respect to water of less than 70 degrees;
With
The second fuel battery cell is
A second membrane electrode assembly having a second anode electrode, a second electrolyte membrane, and a second cathode electrode in this order;
A second flow path plate disposed on the second anode pole side, wherein a second in-cell fuel flow path for circulating liquid fuel is disposed on the second anode pole side surface;
A second gas-liquid separation layer disposed on the second anode electrode side surface of the second flow path plate so as to cover the fuel flow path in the second cell, and capable of transmitting a vaporized component of the liquid fuel;
A fuel cell comprising:

[2] The first fuel cell and the second fuel cell so that the supply flow rates of the liquid fuel to all the first in-cell fuel flow paths and the second in-cell fuel flow paths are substantially the same. The fuel cell according to [1], wherein the cell is disposed.

[3] including at least one row of fuel cell assemblies in which one or more first fuel cells and one or more second fuel cells are arranged in a line;
The fuel cell according to [1] or [2], wherein the fuel cell disposed at at least one end of the fuel cell assembly is the first fuel cell.

[4] The fuel cell according to [3], wherein the fuel cell assembly includes two first fuel cells arranged at both ends thereof and one or more second fuel cells.

[5] An out-cell fuel flow path that is connected to each of the first in-cell fuel flow path and the second in-cell fuel flow path and distributes the liquid fuel to each fuel cell of the fuel cell. The fuel cell according to any one of [1] to [4], further comprising a fuel distributor.

[6] The fuel distribution section has one inlet for introducing the liquid fuel,
[5] The fuel cell according to [5], wherein the out-cell fuel flow path includes a main flow path connected to the introduction port, and a branch flow path connecting the main flow path and each in-cell fuel flow path.

[7] The first fuel cell further includes a first anode current collecting layer laminated on the first anode electrode, and a first cathode current collecting layer laminated on the first cathode electrode,
The second fuel cell further includes a second anode current collecting layer laminated on the second anode electrode and a second cathode current collecting layer laminated on the second cathode electrode. ] The fuel cell in any one of.

[8] The fuel cell according to any one of [1] to [7], which is a direct alcohol fuel cell.

According to the present invention, in a fuel cell in which a plurality of modular fuel cells having fuel flow paths are arranged on the same plane, the uniformity of fuel supply to each fuel cell can be improved. The fuel cell of the present invention is useful as a power source for electronic devices, particularly portable electronic devices.

It is a schematic top view which shows an example of the fuel cell which concerns on this invention. FIG. 2 is a schematic sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line III-III shown in FIG. 2. FIG. 4 is a schematic sectional view taken along line IV-IV shown in FIG. 1. It is a schematic sectional drawing which shows another example of the fuel cell which concerns on this invention. It is a schematic sectional drawing which shows another example of the fuel cell which concerns on this invention. 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 sectional drawing which shows another example of the 1st fuel cell used for the fuel cell which concerns on this invention. It is a schematic top view which shows the 2nd intervening layer with which the 1st fuel battery cell shown by FIG. 9 is provided. 1 is a schematic cross-sectional view showing a fuel cell manufactured in Example 1. FIG. FIG. 3 is a schematic perspective view showing a fuel distribution unit used in Example 1. It is a figure which shows the change of the output voltage for every fuel cell in the fuel cell produced in Example 1. FIG.

Hereinafter, the fuel cell of the present invention will be described in detail with reference to embodiments.
1 is a schematic top view showing an example of a fuel cell according to the present invention, FIG. 2 is a schematic cross-sectional view taken along line II-II shown in FIG. 1, and FIG. 3 is a schematic cross-sectional view taken along line III-III shown in FIG. It is sectional drawing. FIG. 4 is a schematic sectional view taken along line IV-IV shown in FIG.

A fuel cell 100 shown in these drawings is a planar integrated fuel cell including two first fuel cells 101 and one second fuel cell 102 arranged on the same plane, more specifically. Is arranged adjacent to the side surface of the fuel cell assembly 110, and the fuel cell assembly 110 in which two first fuel cells 101 and one second fuel cell 102 are arranged in a line. And a fuel distributor 150. The fuel cells constituting the fuel cell 100 are electrically connected in series or in parallel.

The fuel cell 100 uses the first fuel cell 101 as the fuel cell at both ends of the fuel cell assembly 110 composed of three fuel cells, and uses the second fuel cell 102 as the central fuel cell. It is one of the features. Both the first fuel cell 101 and the second fuel cell 102 are modularized fuel cells having fuel flow paths in the cells, but have different cell structures.

Referring to FIG. 2, the first fuel cell 101 includes a first membrane electrode assembly 4 having a first anode electrode 2, a first electrolyte membrane 1, and a first cathode electrode 3 in this order; First anode current collecting layer 5 laminated on and electrically connected thereto; first cathode current collecting layer 6 laminated on first cathode electrode 3 and electrically connected thereto; first anode A first anode moisturizing layer 7 laminated on the first anode current collecting layer 5 so as to be in contact with the current collecting layer 5; laminated on the first cathode current collecting layer 6 so as to be in contact with the first cathode current collecting layer 6 First cathode moisturizing layer 8; disposed on the first anode electrode 2 side (below the first anode electrode 2), and a first in-cell fuel flow path 10a for flowing liquid fuel is formed on the surface of the first anode electrode 2 side. The first flow path plate 10 disposed between the first membrane electrode assembly 4 and the first flow path plate 10. The first gas-liquid separation layer 12 that is permeable to the vaporized component of the liquid fuel; disposed between the first gas-liquid separation layer 12 and the first anode moisturizing layer 7, and includes a first vaporized fuel storage portion 9a. A first vaporized fuel plate 9; and a first intervening layer 11 disposed between the first gas-liquid separation layer 12 and the first flow channel plate 10 so as to cover the first in-cell fuel flow channel 10a. ing. The first intervening layer 11 is a layer having a contact angle with water of less than 70 degrees.

The second fuel cell 102 includes a second membrane electrode assembly 4 ′ having a second anode electrode 2 ′, a second electrolyte membrane 1 ′, and a second cathode electrode 3 ′ in this order; on the second anode electrode 2 ′. Second anode current collecting layer 5 ′ laminated and electrically connected thereto; second cathode current collecting layer 6 ′ laminated on second cathode electrode 3 ′ and electrically connected thereto; A second anode moisture retention layer 7 ′ laminated on the second anode current collection layer 5 ′ so as to be in contact with the anode current collection layer 5 ′; a second cathode current collection layer 6 so as to be in contact with the second cathode current collection layer 6 ′ 'Second cathode moisturizing layer 8' stacked on the second anode electrode 2 'side (below the second anode electrode 2') and the second in-cell fuel flow path 10a for flowing liquid fuel A second flow path plate 10 'arranged on the surface of the second anode electrode 2'; a second membrane electrode assembly 4 '; A second gas-liquid separation layer 12 ′ disposed between the two flow path plates 10 ′ and capable of transmitting a vaporized component of the liquid fuel; and a second gas-liquid separation layer 12 ′ and a second anode moisturizing layer 7 ′ And a second vaporized fuel plate 9 ′ having a second vaporized fuel storage portion 9a ′.

The difference between these fuel cells is that the first fuel cell 101 has the first intervening layer 11 disposed between the first gas-liquid separation layer 12 and the first flow path plate 10, while the second fuel cell 101 The battery cell 102 does not have such an intervening layer, and the second gas-liquid separation layer 12 ′ is laminated directly on the second in-cell fuel flow path 10a ′.

3 and 4, the fuel distributor 150 distributes the liquid fuel introduced through the inlet 151 to each fuel cell (all the first fuel cells 101 and the second fuel cells 102). Therefore, it is a member independent of the fuel cell, and has an out-cell fuel flow path 155 connected to each of the first in-cell fuel flow path 10a and the second in-cell fuel flow path 10a ′. . For example, the out-cell fuel flow path 155 can be constituted by a main flow path 152 connected to the inlet 151 and a branch flow path 153 connecting the main flow path 152 and each in-cell fuel flow path.

The fuel distributor 150 is a substantially rectangular parallelepiped member attached adjacent to the longitudinal end surface of the fuel cell assembly 110 in which the inlet end of the in-cell fuel flow path of each fuel cell is disposed. The introduction port 151 is provided approximately at the center with respect to the longitudinal direction of the fuel distribution unit 150 (parallel to the arrangement direction of the fuel cells).

According to the fuel cell 100 in which the first fuel cell 101 and the second fuel cell 102 having different cell structures are combined and arranged at appropriate positions, the uniformity of fuel supply to each fuel cell is improved. be able to. That is, when considering the fuel distributor 150 in a state where no fuel cells are connected, the distance from the inlet 151 to the outlet end of the branch channel 153 is long, and X and Y in FIG. Due to the fact that bubbles tend to stay at the end of the fuel flow path 155 outside the cell as shown, the outlet side end of the fuel flow path 155 outside the cell (connected to the fuel flow path inside the cell) The pressure loss of the liquid fuel at the end to be performed, that is, the outlet of the branch flow path 153 becomes larger at the outlet side end located farther from the inlet 151.

Such a problem of nonuniform pressure loss is the same even when fuel cells having the same cell structure are connected to the fuel distributor 150. When the fuel cells constituting the fuel cell assembly 110 connected to the fuel distributor 150 all have the same cell structure, the pressure loss of the liquid fuel at the outlet side end of the out-cell fuel flow path 155 The end portion connected to the fuel cell located farther from 151 becomes larger. In the configuration in which the introduction port 151 is installed at the center in the longitudinal direction of the fuel distribution unit 150, when all the fuel cells constituting the fuel cell assembly 110 have the same cell structure, the fuel cell assembly. The pressure loss at the ends connected to the fuel cells arranged at both ends of 110 becomes relatively large, and the supply flow rate of liquid fuel to the in-cell fuel flow path becomes relatively small.

On the other hand, the first fuel cell 101 having the first intervening layer 11 having hydrophilicity on both ends of the fuel cell assembly 110 where the pressure loss is relatively large is provided on the in-cell fuel flow path 10a. Since a force for drawing the liquid fuel is generated on the basis of the hydrophilicity (wetting property) (the pressure loss of the liquid fuel in the in-cell fuel flow path is reduced), the fuel cell assembly 110 The supply flow rate of the liquid fuel to the in-cell fuel flow path of the fuel cells arranged at both ends can be increased, the fuel supply can be made uniform among the fuel cells, and all the first cells can be made uniform. The supply flow rate of the liquid fuel to the inner fuel flow path 10a and the second cell fuel flow path 10a ′ can be made substantially the same.

Uniform fuel supply enables stable power generation and the power generation characteristics of fuel cells that have been fuel deficient can be raised to a high level, thus improving the power generation characteristics of the entire fuel cell. it can. In addition, since variation in power generation between fuel cells is reduced, temperature variation between fuel cells is also reduced. This also leads to stable power generation.

Although the number of fuel cells included in the fuel cell is not particularly limited as long as it is 2 or more, it is preferably 3 or more. FIG. 5 is a schematic cross-sectional view similar to FIG. 3 showing a form in which the fuel cell assembly 110 is composed of four fuel cells arranged in a line. Also in this example, the introduction port 151 is installed at approximately the center in the longitudinal direction of the fuel distributor 150, and both ends of the fuel cell assembly 110 are arranged in order to make the fuel supply uniform between the fuel cells. The 1st fuel cell 101 provided with the 1st intervening layer 11 is arranged.

FIG. 6 shows a mode in which the fuel cell assembly is composed of three fuel cells arranged in a line, and the introduction port 151 is installed at one end in the longitudinal direction of the fuel distribution unit 150. FIG. 4 is a schematic sectional view similar to FIG. 3. In such a configuration, the distance from the inlet 151 to the outlet side end of the out-cell fuel flow path 155 is particularly long, and the end of the out-cell fuel flow path 155 as shown by Z in FIG. In order to make the fuel supply uniform between the fuel cells, the end on the side opposite to the inlet installation position in the fuel cell assembly 110 is likely to be retained. A first fuel cell 101 having a first intervening layer 11 is disposed in the part.

The fuel cell of the present invention may include, for example, two or more fuel cell assemblies composed of a plurality of fuel cells arranged in a line, and includes two or more fuel distribution portions. There may be. You may make it couple | bond a fuel cell assembly with two side surfaces which one fuel distribution part opposes, respectively.

As described above, in the fuel cell according to the present invention, the pressure loss of the liquid fuel at the outlet side end portion (connection point with the in-cell fuel flow path) of the out-cell fuel flow path is considered, and the relative pressure The first fuel battery cell in which the pressure loss of the liquid fuel in the in-cell fuel flow path is relatively low due to the hydrophilicity of the first intervening layer is disposed at the location where the loss is large, while the pressure loss is relatively low. By disposing the second fuel cell not having the first intervening layer in a small place, the overall pressure loss is balanced, and the fuel supply between the fuel cells is made uniform. The supply flow rates of the liquid fuel to the in-cell fuel flow path and the second in-cell fuel flow path are made substantially the same.

Since the fuel cell according to the present invention uses a fuel cell having a fuel flow path in the cell as a module, only the number of modules, the arrangement pattern, the shape of the fuel distribution part, etc. are changed in design. Thus, the present invention can be easily applied to electronic devices having different shapes and areas of fuel cell accommodation spaces. Such flexibility of the fuel cell structure design is extremely effective for improving the production efficiency of the fuel cell (simplification of the production process) and reducing the production cost.

Next, each member constituting the fuel cell of the present invention will be described in detail.
(1) First fuel cell [First electrolyte membrane]
The first electrolyte membrane 1 constituting the first membrane electrode assembly 4 has a function of transmitting protons from the first anode electrode 2 to the first cathode electrode 3, and the electricity between the first anode electrode 2 and the first cathode electrode 3. It has the function of maintaining the electrical insulation and preventing short circuit. The material of the electrolyte membrane 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 glass phosphate, 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 1 is, for example, 1 to 200 μm.

[First anode electrode and first cathode electrode]
The first anode electrode 2 laminated on one surface of the first electrolyte membrane 1 and the first cathode electrode 3 laminated on the other surface are each a catalyst layer comprising a porous layer containing at least a catalyst and an electrolyte. Is provided. In the first anode electrode 2, a catalyst (anode catalyst) catalyzes a reaction that generates protons and electrons from the fuel, and the electrolyte has a function of conducting the generated protons to the first electrolyte membrane 1. In the first cathode electrode 3, the catalyst catalyzes a reaction for generating water from protons conducted through the electrolyte and an oxidant (such as air).

The catalyst of the first anode electrode 2 and the first cathode electrode 3 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 1st anode pole 2 and the 1st cathode pole 3 can be improved. By improving the water retention, it is possible to improve the resistance of the first electrolyte membrane 1 accompanying proton transfer and the potential distribution in the first anode electrode 2 and the first cathode electrode 3.

Each of the first anode electrode 2 and the first cathode electrode 3 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 2 and the first cathode electrode 3 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 5 and the first cathode current collecting layer 6 are laminated on the first anode electrode 2 and the first cathode electrode 3, respectively. The first anode current collecting layer 5 and the first cathode current collecting layer 6 have a function of collecting electrons in the first anode electrode 2 and the first cathode electrode 3 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, Al, Cu, Ag, Zn; and nitrides or carbides of these metals; and 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 5 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 2. Or it can be a flat plate having a punching metal shape. This through hole also functions as a path for guiding the by-product gas (CO ₂ gas or the like) generated in the catalyst layer of the first anode electrode 2 to the first vaporized fuel storage unit 9a side. Similarly, the first cathode current collecting layer 6 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 3. 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 10 is a plate-like body in which a first in-cell fuel flow path 10a for flowing liquid fuel is formed on the surface of the first anode electrode 2 side, and the first anode electrode 2 side of the fuel cell. Placed in. The first in-cell fuel flow path 10a can be formed 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 10a is not particularly limited, but is arranged uniformly 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 2. It is preferable. FIG. 3 shows a preferred example of the flow path pattern. The hatched portions of the first flow path plate 10 and the second flow path plate 10 ′ shown in FIG. 3 indicate grooves (recesses) (the same applies to FIGS. 5, 6, and 11). The first in-cell fuel flow path 10a and the second in-cell fuel flow path 10a ′ shown in FIG. 3 are connected to the out-cell fuel flow path 155 at four locations, respectively. The four flow paths connected to the out-cell fuel flow path 155 are once aggregated into one flow path, and five flow paths extend from the flow path at regular intervals in a branch shape. Note that the circles (seven in each case) drawn on the periphery of each fuel cell in FIG. 3 indicate screw holes used for fastening between the members (the same applies to FIGS. 5, 6, and 11).

Other examples of the channel shape include a channel shape that does not have a branched portion (for example, a plurality of channels that extend linearly from the connection point with the fuel flow path outside the cell), a mesh-like channel, and a surface. A tank-shaped flow path formed of a large concave portion formed on the surface.

The width and depth of the channel in the cell are not particularly limited, but for example, each is about 0.2 to 1.5 mm (especially larger in the case of a tank type channel), about 0.1 to 0.6 mm. is there.

The first flow path plate 10 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 gas-liquid separation layer]
The first gas-liquid separation layer 12 disposed between the first membrane electrode assembly 4 and the first flow path plate 10 and on the surface of the first intervening layer 11 described later on the first anode electrode 2 side, Gas-liquid separation that is a porous layer that is permeable to vaporized fuel (property of vaporized components of liquid fuel) and has a hydrophobic property that is impermeable to liquid fuel, and enables vaporized supply of fuel to the first anode electrode 2 It is a layer having a function. The first gas-liquid separation layer 12 controls (limits) the amount or concentration of vaporized fuel supplied to the first anode electrode 2 to an appropriate amount and also has a function of making it uniform. By providing the first gas-liquid separation layer 12, it is possible to effectively suppress the crossover of the fuel, hardly generate temperature unevenness in the power generation unit, and maintain a stable power generation state.

The first gas-liquid separation layer 12 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 12 is preferably 0.1 to 10 μm, preferably 0.5 to 5 μm. More preferably. The maximum pore diameter can be obtained by measuring the bubble point using methanol or the like as in the first intervening layer 11 described later. The first gas-liquid separation layer 12 has a contact angle with water, which will be described later, usually 80 degrees or more, and more typically 90 degrees or more.

The thickness of the first gas-liquid separation layer 12 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. From the viewpoint of reducing the thickness of the fuel cell, the thickness of the first gas-liquid separation layer 12 is preferably 500 μm or less, and more preferably 300 μm or less.

[First intervening layer]
The first gas-liquid separation layer 12 and the first flow path plate 10 so as to cover the first anode electrode 2 side surface of the first flow path plate 10 (therefore, the groove (recess) forming the first in-cell fuel flow path 10a). The 1st intervening layer 11 arrange | positioned between these is a layer which has the hydrophilicity whose contact angle with respect to water is less than 70 degree | times. By arranging such a layer so as to cover the first in-cell fuel flow path 10a, the liquid fuel is drawn into the first in-cell fuel flow path 10a based on the hydrophilicity of the first intervening layer 11. Therefore, the pressure loss of the liquid fuel inside the first in-cell fuel flow path 10a can be reduced. The contact angle of the first intervening layer 11 with respect to water is measured in accordance with JIS R 3257 (substrate glass surface wettability test).

The first intervening layer 11 preferably exhibits a capillary action with respect to the liquid fuel, and more preferably has a relatively large capillary force so that the nonuniformity of the fuel supply can be corrected more effectively. From such a viewpoint, the first intervening layer 11 preferably has pores, and the maximum pore diameter is preferably 1 μm or less, and more preferably 0.7 μm or less. The maximum pore diameter can be obtained by measuring the bubble point described later, but can be measured by mercury porosimetry as another method. However, since the mercury intrusion method can measure only a pore distribution of 0.005 μm to 500 μm, it is an effective measuring means when pores outside this range do not exist or can be ignored.

The first intervening layer 11 is not particularly limited, but the bubble point when the measurement medium is methanol can be, for example, about 5 kPa or more. When applying a higher capillary force, the bubble point is preferably high. From such a viewpoint, the bubble point may be 30 kPa or more, and further may be 50 kPa or more.

On the other hand, bubbles generated in the liquid fuel in the first in-cell fuel flow path 10a or the out-cell fuel flow path during power generation are transferred to the first vaporized fuel via the first intervening layer 11 and the first gas-liquid separation layer 12. In the embodiment in consideration of allowing escape to the housing portion 9a side and discharging to the outside of the fuel cell, the bubble point of the first intervening layer 11 is preferably low. In such an embodiment, mainly the hydrophilicity (surface wettability) of the first intervening layer 11 contributes to the reduction of the pressure loss of the liquid fuel inside the first in-cell fuel flow path 10a.

The bubble point is the minimum pressure at which bubbles are observed on the surface of the layer (membrane) when air pressure is applied from the back side of the layer (membrane) wetted with the liquid medium. The bubble point ΔP is expressed by the following formula (1):
ΔP [Pa] = 4γcos θ / d (1)
(Γ is the surface tension [N / m] of the measurement medium, θ is the contact angle between the material of the layer (film) and the measurement medium, and d is the maximum pore diameter of the layer (film)).
Defined by In the present invention, the bubble point is measured according to JIS K3832, using methanol as the measurement medium.

Examples of the first intervening layer 11 include a porous layer made of a polymer material, a metal material, an inorganic material, or the like, or a polymer film. Specific examples are as follows.

1) A porous layer made of the following materials. Fluorine resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); acrylic resins; ABS resins; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate; cellulose acetate and nitrocellulose Cellulose resins such as ion exchange cellulose; Nylon; Polycarbonate resins; Chlorine resins such as polyvinyl chloride; Polyetheretherketone; Polyethersulfone; Glass; Ceramics; Stainless steel, titanium, tungsten, nickel, aluminum, steel, etc. Metal material. The porous layer can be a foam, a sintered body, a nonwoven fabric or a fiber (such as glass fiber) made of these materials. Among these materials, when a hydrophobic material is used as a base material, the contact angle is improved by applying a hydrophilic treatment by a method such as introducing a hydrophilic functional group and increasing the wettability of the pore surface to water. Can be adjusted to less than 70 degrees.

2) A polymer film made of the following materials. Perfluorosulfonic acid polymer; styrene graft polymer, trifluorostyrene derivative copolymer, sulfonated polyarylene ether, sulfonated polyetheretherketone, sulfonated polyimide, sulfonated polybenzimidazole, phosphonated polybenzimidazole Those that can be used as electrolyte membrane materials such as hydrocarbon polymers such as sulfonated polyphosphazene. These polymer films have nano-order pores as gaps between polymers that are three-dimensionally entangled.

Among the materials listed above, when a hydrophobic material is used as a base material, it is subjected to a hydrophilic treatment by a method such as introducing a hydrophilic functional group, and by increasing the wettability of the pore surface to water, The contact angle can be adjusted to less than 70 degrees.

The thickness of the first intervening layer 11 is not particularly limited, but is preferably 20 to 500 μm, more preferably 50 to 200 μm from the viewpoint of reducing the thickness of the fuel cell.

[First vaporized fuel plate]
7A is a schematic top view showing the first vaporized fuel plate 9 used in the first fuel battery cell 101, and FIG. 7B is a cross-sectional view taken along line VII-VII shown in FIG. 7A. It is a schematic sectional drawing. The first vaporized fuel plate 9 forms a space for accommodating vaporized fuel (that is, the first vaporized fuel accommodating portion 9a) between the first membrane electrode assembly 4 and the first gas-liquid separation layer 12. It is a member. In the example of FIG. 2, the first vaporized fuel plate 9 is disposed between the first anode moisturizing layer 7 and the first gas-liquid separation layer 12 so as to be in contact with the first anode moisturizing layer 7. The first vaporized fuel plate 9 is a first vaporized fuel storage portion 9a that is a through-hole penetrating in the thickness direction, and a first communication path that connects the first vaporized fuel storage portion 9a and the outside of the first vaporized fuel plate 9 9b. The first communication path 9b is a path for discharging by-product gas (CO ₂ gas or the like) generated at the first anode electrode 2 to the outside of the fuel cell.

In the first vaporized fuel plate 9 shown in FIG. 7, the first communication path 9b is provided at the peripheral portion of the first vaporized fuel plate 9, and extends from the first vaporized fuel storage portion 9a to the end surface of the peripheral portion (recessed portion). ). The outlet of the first communication path 9b is provided, for example, on the side surface facing the side surface of the fuel cell to which the fuel distributor 150 is coupled (see FIG. 4).

By providing the first vaporized fuel storage portion 9a via the first gas-liquid separation layer 12 on the first in-cell fuel flow path 10a, the first anode electrode surface of the vaporized fuel concentration supplied to the first anode electrode 2 In the interior and optimization of the amount of vaporized fuel is promoted.

Providing the first vaporized fuel storage portion 9a is also advantageous in the following points.
(I) Heat insulation between the power generation unit (first membrane electrode assembly 4) and the first in-cell fuel flow path 10a can be achieved by the air layer present in the first vaporized fuel storage unit 9a. Thereby, the crossover by the temperature of the liquid fuel in the 1st in-cell fuel flow path 10a rising too much can be suppressed. This contributes to suppression of runaway battery internal temperature and increase in internal pressure.

(Ii) The by-product gas such as CO ₂ gas generated at the first anode electrode 2 reaches the first vaporized fuel storage portion 9a with heat generated by power generation, and then passes through the first communication path 9b. And discharged outside the fuel 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 10a can be suppressed. This also contributes to suppression of battery internal temperature runaway and internal pressure rise. In particular, since the first vaporization fuel plate 9 is provided with the first communication path 9b (by-product gas discharge port), it is difficult for heat to be transmitted to the first in-cell fuel flow path 10a. The excessive temperature rise of the liquid fuel in the inner fuel flow path 10a, and the accompanying crossover and temperature runaway are less likely to occur.

(Iii) By-product gas can be satisfactorily discharged from the first communication path 9b, fuel supply hindrance due to poor discharge of by-product gas can be suppressed, and fuel supply to the first anode electrode 2 is excellent. Can be done. Thereby, stable power generation characteristics can be obtained. Moreover, since by-product gas can be discharged | emitted favorably from the 1st communication path | route 9b, the penetration | invasion into the fuel flow path 10a in 1st cell 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 2, so that the output stability of the fuel cell can be improved.

The thickness of the first vaporized fuel plate 9 can be set to, for example, about 100 to 1000 μm, and the above effects can be sufficiently obtained even when the thickness is reduced to about 100 to 300 μm.

From the viewpoint of heat insulation between the power generation unit and the first in-cell fuel flow path 10a, the through-hole (first vaporized fuel storage unit 9a) of the first vaporized fuel plate 9 is as shown in FIG. It is preferable to make the aperture ratio with respect to the area of the first vaporized fuel plate 9 as large as possible. Therefore, it is preferable that the first vaporized fuel plate 9 has a frame shape (b-shaped) having as large a through-hole 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 9 (as will be described later, the first vaporized fuel plate 9 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 first vaporized fuel plate 9 to make the concentration of the fuel supplied to the first anode electrode 2 uniform. It is also advantageous in securing a sufficient fuel supply. In addition, the opening rate of a through-hole is 90% or less normally.

The first communication path 9b is not limited to a groove (concave portion) provided in the peripheral portion of the first vaporized fuel plate 9, and may be a through hole penetrating in the thickness direction. It is preferable to consist of a groove | channel (concave part). From the viewpoint of the strength of the first vaporized fuel plate 9, the depth of the first communication path 9 b is preferably up to about 75% of the thickness of the first vaporized fuel plate 9.

FIG. 8A is a schematic top view showing another example of the first vaporized fuel plate, and FIG. 8B is a schematic cross-sectional view taken along the line VIII-VIII shown in FIG. 8A. As shown in FIG. 8, the first vaporized fuel plate may have two or more through holes. The first vaporized fuel plate 99 shown in FIG. 8 has a total of four through-holes 99a 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. 7, 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 same number of first communication paths provided on the peripheral edge portion as the number of through holes may be provided for each through hole. A smaller or larger number of communication paths can be provided. In the example of FIG. 8, two first communication paths 99b are provided for the four through holes 99a. Thus, although it is not necessary to provide the first communication path for each through-hole, in that case, as shown in FIG. 8, the through-hole (FIG. 8 (a) where the first communication path 99b is not provided. The lower two through-holes 99a) are spatially connected to the through-hole provided with the first communication path 99b (the upper two through-holes 99a in FIG. 8A) by the first connection path 99c. . The 1st connection path | route 99c can be the groove | channel (recessed part) provided in the beam between through-holes similarly to the 1st communication path | route 99b (refer FIG.8 (b)). By providing the first connection path 99c, the by-product gas that has entered the through hole in which the first communication path 99b is not provided can be discharged to the outside through the first communication path 99b.

Supply to the first anode electrode 2 of the first vaporized fuel plate in order to improve the discharge efficiency of the by-product gas that has reached the through-hole (first vaporized fuel storage unit) of the first vaporized fuel plate In order to enhance the function of equalizing the concentration of the generated fuel, the through holes provided with the first communication path 99b and / or the through holes not provided with the first communication path 99b are spatially connected. It is also preferable to provide one connection path 99d (see FIG. 8A).

The ratio S ₁ / S between the cross-sectional area of the first communication path (the total of these cross-sectional areas if there are two or more first communication paths) S ₁ and the total area S ₀ of the side surfaces of the first vaporized fuel plate ₀ is required to be larger than 0 in order to discharge by-product gas and heat accompanying it, and is 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, fuel leakage or air mixing is likely to occur, and power generation stability may be reduced.

For example, when all of the first communication path is provided on the side facing the side of the fuel cell to which the fuel distributor 150 is coupled, only one of the four peripheral edges of the first vaporized fuel plate is 1 Alternatively, when two or more first communication paths are provided, the cross-sectional area of the first communication path (the sum of these cross-sectional areas when there are two or more first communication paths) S ₁ and the first communication path are provided. The ratio S ₁ / S _{2 to} the cross-sectional area S ₂ of the side surface at the peripheral edge is preferably 0.008 or more for the same reason as described above.

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 with high rigidity is used, the first vaporized fuel plate and the adjacent member can be joined by hot pressing (thermocompression bonding), reducing variations in fuel cell thickness and power generation characteristics. can do. Further, it is possible to effectively prevent the first communication path from being blocked during hot pressing.

In addition, although the 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 cathode moisturizing layer and first anode moisturizing layer]
The first cathode moisturizing layer 8 is disposed on the first cathode electrode 3, preferably on the first cathode current collecting layer 6, and water generated at the first cathode electrode 3 is allowed to flow from the first cathode electrode 3 side to the fuel cell. This is an optional layer for preventing evaporation from the cell. By providing the first cathode moisturizing layer 8, water generated at the first cathode electrode 3 is efficiently returned to the first anode electrode 2 through the first electrolyte membrane 1 without evaporating outside the fuel cell, It can be used effectively for the reaction at the first anode electrode 2.

The first anode moisturizing layer 7 is disposed between the first anode electrode 2 or the first anode current collecting layer 5 and the first vaporized fuel storage unit 9a, and the moisture in the first anode electrode 2 is used to make the first anode This is an optional layer for preventing evaporation from the electrode 2 side to the outside of the first membrane electrode assembly (for example, to the first vaporized fuel housing portion 9 a) and for retaining the first anode electrode 2. By providing the first anode moisturizing layer 7, water generated at the first cathode electrode 3 and reaching the first anode electrode 2 through the first electrolyte membrane 1 is evaporated to the outside of the first membrane electrode assembly 4. And can be held well in the first anode electrode 2. Thereby, since the water is effectively used for the reaction at the first anode electrode 2, the reaction efficiency at the first anode electrode 2 is improved, and high power generation characteristics can be stably exhibited. In particular, the combined use with the first cathode moisturizing layer 8 can achieve the effect more effectively.

Also, the installation of the first cathode moisturizing layer 8 and the first anode moisturizing layer 7 is effective for preventing the drying of the first electrolyte membrane 1 and the accompanying increase in cell resistance and degradation of power generation characteristics.

The first cathode moisturizing layer 8 and the first anode moisturizing layer 7 are gas permeable so as to be able to permeate vaporized fuel or oxidant (air etc.) from the outside of the fuel cell, are insoluble in water, and It is composed of a material having moisture retention (property that 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 8 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). 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 keep the water generated at the first cathode electrode 3 in the fuel cell. On the other hand, when the porosity is less than 30%, the diffusion of an oxidant (air or the like) from the outside of the fuel cell is hindered, and the power generation characteristics of the first cathode electrode 3 are likely to deteriorate.

The first anode moisturizing layer 7 is gas permeable so as to allow the by-product gas (CO ₂ gas, etc.) 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 may be difficult to retain water generated in the first cathode electrode 3 and reaching the first anode electrode 2 via the first electrolyte membrane 1 in the first membrane electrode assembly. . 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 2 are likely to deteriorate.

The porosity of the first cathode moisturizing layer 8 and the first anode moisturizing layer 7 is determined by measuring the volume and weight of the moisturizing layer, obtaining the specific gravity of the moisturizing layer, and calculating the specific gravity of the moisturizing layer and the specific gravity of the material from the following formula (2):
Porosity (%) = [1− (specific gravity of moisture retaining layer / material specific gravity)] × 100 (2)
Can be calculated.

The thickness of the first cathode moisturizing layer 8 and the first anode moisturizing layer 7 is not particularly limited, but is 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.

The first cathode moisturizing layer 8 and the first anode moisturizing layer 7 should 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 such a viewpoint, the first cathode moisturizing layer 8 and the first anode moisturizing layer 7 are, among the above, fluorine resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); A porous film (porous layer) made of a silicone resin or the like is preferable. Specifically, “NTF2026A-N06” and “NTF2122A-S06” manufactured by Nitto Denko Corporation, which are porous films made of polytetrafluoroethylene (TEMISH (registered trademark)), can be exemplified.

The first anode moisturizing layer 7 includes a first anode current collecting layer 5 disposed on the first anode electrode 2, and is laminated on the first anode current collecting layer 5 so as to be in contact with the first anode current collecting layer 5. It is preferable. Thereby, it can prevent more effectively that the water | moisture content in the 1st anode electrode 2 is transpired out of the 1st membrane electrode assembly 4. FIG.

The first cathode moisturizing layer 8 and the first anode moisturizing layer 7 are provided as necessary, and at least one of these may be omitted.

[Second intervening layer]
The first fuel battery cell 101 may have a second intervening layer 13 interposed between the first intervening layer 11 and the first gas-liquid separation layer 12. FIG. 9 shows an example of the first fuel cell including the second intervening layer 13. The first fuel cell 901 shown in FIG. 9 has the first fuel cell shown in FIG. 2 except that it has a second intervening layer 13 between the first intervening layer 11 and the first gas-liquid separation layer 12. 101. FIG. 10 is a schematic top view showing the second intervening layer 13 used in the first fuel cell 901.

The second intervening layer 13 is a layer having a through-hole penetrating in the thickness direction through which liquid fuel can permeate, and plays a role in surface-bonding at least the first intervening layer 11 and the first gas-liquid separation layer 12 with good adhesion. It preferably has a function of adjusting (limiting) the amount of liquid fuel permeation to the first gas-liquid separation layer 12 side. As the 2nd intervening layer 13, the non-porous sheet | seat (film) which has a through-hole penetrated in the thickness direction as shown, for example in FIG. 10 can be used, and a thermoplastic resin can be illustrated preferably as the material. . By using this, a laminated body composed of the first intervening layer / the second intervening layer / the first gas-liquid separation layer is subjected to thermocompression bonding so that the respective layers can be surface-bonded with good adhesion. The 1st fuel cell which has the non-porous sheet | seat which has the through-hole penetrated in the thickness direction as the 2nd intervening layer 13, and can be surface-bonded is advantageous in the following points.

(I) Since the first intervening layer 11 and the first gas-liquid separating layer 12 can be bonded with good adhesion via the second intervening layer 13, the first intervening layer 11 and the first gas-liquid separating layer 12 By-product gas does not stay between the first gas-liquid separation layer 12 and variation in the amount of vaporized fuel permeation in the surface of the first gas-liquid separation layer 12 can be suppressed. Can be performed.

(Ii) Depending on the number of through-holes formed in the second intervening layer 13 and the opening diameter, the amount of liquid fuel permeated to the first gas-liquid separation layer 12 side and, in turn, the amount of vaporized fuel supplied to the first anode electrode 2 are adequate Can be adjusted (restricted) to an appropriate amount. As a result, it is possible to prevent or suppress the crossover of the fuel and stabilize the fuel supply. The number of through holes is not particularly limited, but it is preferable that there are a plurality of through holes. From the viewpoint of uniformizing the amount of vaporized fuel permeation in the first gas-liquid separation layer 12 surface, the through holes are formed in the second intervening layer 13 surface. It is preferable to distribute it uniformly. The opening diameter (diameter) of the through hole can be set to about 0.1 to 5 mm, for example.

In addition to the thermoplastic resin sheet described above, the second intervening layer 13 may be formed of, for example, the following.

1) A porous layer formed from an adhesive resin or resin composition, for example, a porous layer formed from an adhesive such as a hot-melt adhesive or a curable adhesive. When the adhesive is used, the second intervening layer 13 is an adhesive layer, that is, a porous layer made of the adhesive or a cured product thereof. The liquid fuel permeation amount to the first gas-liquid separation layer 12 side is adjusted (limited) by the pores of the porous layer.

2) A through-hole penetrating in the thickness direction, preferably including a non-porous metal plate. In this case, an adhesive layer is formed on both surfaces of the metal plate in order to ensure good adhesion between the first intervening layer 11 and the first gas-liquid separating layer 12, and therefore the second intervening layer 13 is And a three-layer structure of adhesive layer / metal plate / adhesive layer. The adhesive layer is a porous layer made of an adhesive or a cured product thereof. The adhesive may be a hot melt adhesive or a curable adhesive. The liquid fuel permeation amount to the first gas-liquid separation layer 12 side can be adjusted (controlled) by the number of through holes formed in the metal plate and the opening diameter, as in the case of the thermoplastic resin sheet. The adhesive layer is preferably formed so as not to block the through hole.

(2) Second fuel cell 2nd membrane electrode assembly 4 ′ (second anode electrode 2 ′, second electrolyte membrane 1 ′ and second cathode electrode 3 ′) constituting the second fuel cell 102, second Anode current collecting layer 5 ′, second cathode current collecting layer 6 ′, second anode moisturizing layer 7 ′, second cathode moisturizing layer 8 ′, second flow path plate 10 ′, second gas-liquid separation layer 12 ′ and second The two vaporized fuel plates 9 'are respectively the first membrane electrode assembly 4 (first anode electrode 2, first electrolyte membrane 1 and first cathode electrode 3), first anode current collecting layer 5, and first cathode current collector. The electric layer 6, the first anode moisturizing layer 7, the first cathode moisturizing layer 8, the first flow path plate 10, the first gas-liquid separation layer 12, and the first vaporized fuel plate 9 have the same configuration. The second fuel battery cell 102 does not have the first intervening layer, and the second gas-liquid separation layer 12 ′ is laminated directly on the second in-cell fuel flow path 10 a ′.

(3) Fuel distribution unit The fuel distribution unit 150 is a member independent of the fuel cells for distributing the liquid fuel introduced through the introduction port 151 to each fuel cell, and the first cell is disposed inside the fuel cell. An out-cell fuel flow path 155 is connected to each of the inner fuel flow path 10a and the second in-cell fuel flow path 10a ′. As described above, the fuel flow path (intra-cell fuel flow path) for distributing the liquid fuel to the region directly below the anode electrode is incorporated in the fuel battery cell as a part of the fuel battery cell, while the liquid fuel is supplied to each fuel battery cell. By forming the fuel flow path (outer cell fuel flow path) for distribution with a member independent of the fuel battery cell, the fuel battery cell can be modularized.

For example, as shown in FIG. 3, the out-cell fuel flow path 155 connects the main flow path 152 connected to the inlet 151 provided on the upper surface, for example, and connects the main flow path 152 to each in-cell fuel flow path. The branch channel 153 can be configured. The fuel distributor 150 is a tank-like hollow member. For example, an inlet 151 is provided on the upper surface, and through holes connected to the fuel flow paths in the cells are formed on the side surfaces connected to the fuel cells. It may be provided (the hollow portion corresponds to the trunk channel and the through hole corresponds to the branch channel).

The outer shape of the fuel distribution unit 150 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 of modules (fuel cell), the arrangement form, and the like. . The fuel distributor 150 can be composed of various plastic materials, metal materials, alloy materials, and the like.

A fuel tank (not shown) for storing liquid fuel is usually connected to the introduction port 151 via a flow path. The fuel supply from the fuel tank to the out-cell fuel flow path and the in-cell fuel flow path is normally performed using a liquid feed pump, but may be passive supply without using auxiliary equipment such as a liquid feed pump.

(4) Type of fuel cell The fuel cell of the present invention can be a polymer electrolyte fuel cell or a direct alcohol fuel cell, and is particularly suitable as a direct alcohol fuel cell (in particular, a direct methanol fuel cell). It is. Examples of the liquid fuel that can be used in the fuel cell of the present invention 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. Can be mentioned. 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 cathode electrode, air or oxygen gas is preferable, and air is particularly preferable.

The fuel cell of the present invention can be suitably used 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.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

<Example 1>
The fuel cell having the configuration shown in FIG. 11 was manufactured by the following procedure. FIG. 11 is a schematic sectional view similar to FIG. 3 and shows the shapes of the out-cell fuel flow path and the in-cell fuel flow path. The planar integrated fuel cell produced in the present example is the same as the fuel cell shown in FIG. 5 except that it includes two fuel cell assemblies composed of four fuel cells arranged in a line. These fuel cell assemblies are respectively coupled to two opposing side surfaces of the fuel distributor 150. The out-cell fuel flow path 155 has branch flow paths 153 extending from the main flow path 152 to both side surfaces so that the fuel cell connection can be made to the in-cell fuel flow paths of the two fuel battery cell assemblies.

Each of the two fuel cell assemblies is a first fuel cell having a first intervening layer disposed at both ends thereof (

first fuel cell

101a and 101b and

first fuel cell

101c and 101d in FIG. 11, respectively). And two second fuel cells arranged in the center (

second fuel cells

102a and 102b and

second fuel cells

102c and 102d in FIG. 11, respectively). The cell structures of the

first fuel cells

101a, 101b, 101c, 101d and the

second fuel cells

102a, 102b, 102c, 102d are respectively the first fuel cell 101, the second fuel cell 102 shown in FIG. It is the same.

(1) Production of first membrane electrode assembly Catalyst-supported carbon particles (TEC66E50, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 32.5 wt% and a Ru loading amount of 16.9 wt%, and 20 wt% of an electrolyte An alcohol solution of Nafion (registered trademark) (manufactured by Aldrich), n-propanol, isopropanol, and zirconia balls are put into a fluororesin container at a predetermined ratio, and are stirred at 500 rpm for 50 minutes. By mixing, a catalyst paste for the first anode electrode was produced. The catalyst paste for the first cathode electrode was prepared in the same manner as the catalyst paste for the first anode electrode, except that the catalyst-supporting carbon particles (TEC10E50E, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 46.8% by weight were used. Produced.

Next, after cutting a 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 first anode electrode is formed on the porous layer. The catalyst paste is applied using a screen printing plate having a window of 30 mm in length and 35 mm in width so that the amount of supported catalyst is about 3 mg / cm ^2, and dried, so that carbon as an anode conductive porous layer is obtained. A first anode electrode 2 having a thickness of about 200 μm and having an anode catalyst layer formed at the center on the paper was produced. A screen 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 catalyst paste for the first cathode electrode is about 1 mg / cm ^2. The first cathode electrode 3 having a thickness of about 70 μm in which a cathode catalyst layer was formed at the center on the carbon paper, which is a cathode conductive porous layer, was prepared by applying using a printing plate and drying.

Next, a perfluorosulfonic acid ion exchange membrane having a thickness of about 175 μm (Nafion (registered trademark) 117, manufactured by DuPont) was cut into a length of 35 mm and a width of 40 mm to form the first electrolyte membrane 1, and the first anode electrode 2 And the first electrolyte membrane 1 and the first cathode electrode 3 in this order so that the respective catalyst layers face the first electrolyte membrane 1, and then thermocompression bonded at 130 ° C. for 2 minutes, The 1 anode electrode 2 and the first cathode electrode 3 were joined to the first electrolyte membrane 1. The superposition is such that the positions of the first anode electrode 2 and the first cathode electrode 3 in the plane of the first electrolyte membrane 1 coincide with each other, and the first anode electrode 2, the first electrolyte membrane 1 and the first cathode electrode. This was done so that the centers of 3 coincided. Next, the outer periphery of the obtained laminate was cut to produce a first membrane electrode assembly (MEA) 4 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 first anode current collecting layer 5 and the first cathode current collecting layer 6.

Next, the first anode current collecting layer 5 is laminated on the first anode electrode 2 via a conductive adhesive layer made of carbon particles and an epoxy resin, and the first cathode current collecting layer 6 is formed as the first cathode current collecting layer 6. The cathode electrode 3 was laminated via the same conductive adhesive layer, and these were joined by thermocompression bonding to produce a MEA-current collecting layer laminate.

(3) Bonding of Moisturizing Layer As the first anode moisturizing layer 7 and the first cathode moisturizing layer 8, a porous film made of polytetrafluoroethylene (“TEMISH (registered trademark)” NTF2122A- manufactured by Nitto Denko Corporation) S06 ", length 22 mm, width 26 mm, thickness 0.2 mm, porosity 75%) were prepared. These moisturizing layers were laminated on the first anode current collecting layer 5 and the first cathode current collecting layer 6 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 the first intervening layer and the first gas-liquid separation layer As the first intervening layer 11, a porous film made of polyvinylidene fluoride having a length of 26.5 mm, a width of 27 mm, and a thickness of 0.1 mm (dura made by MILLIPORE) A pore membrane filter) was used. The contact angle of this porous film with respect to water was less than 70 degrees. The maximum pore diameter of the pores of this porous film was 0.1 μm, and the bubble point based on JIS K3832 was 115 kPa when methanol was used as the measurement medium.

Further, as the first gas-liquid separation layer 12, 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)” manufactured by Nitto Denko Corporation) NTF2122A-S06 ") was used. The contact angle of this porous film with respect to water was about 120 degrees. The bubble point according to JIS K 3832 of this porous film was 18 kPa when the measurement medium was methanol.

The first gas-liquid separation layer 12 was laminated on the first intervening layer 11, and the layer boundary portions on all side surfaces were joined with an adhesive.

(5) Joining of the first vaporized fuel plate By etching, a first vaporized fuel plate 99 made of SUS having a shape shown in FIG. 8 and having a length of 26.5 mm, a width of 27 mm, and a thickness of 0.2 mm was produced (first The communication path 99b and the

first connection paths

99c and 99d are all formed by grooves (concave portions). The opening ratio of the through holes 99a is 63% in total, and the ratio of the total of the two cross-sectional areas of the first communication path 99b to the total area of the side surfaces of the first vaporized fuel plate is 0.04. . The joined body of the first intervening layer 11 and the first gas-liquid separation layer 12 is provided on the surface opposite to the groove forming surface of the first vaporized fuel plate 99, and the first gas-liquid separation layer 12 side is the first vaporization. They were laminated so as to face the fuel plate 99, and these were joined by thermocompression bonding.

(6) Joining of the first flow path plates 26. The first 26 cells provided with the first in-cell fuel flow path 10a (flow path width 1.5 mm, depth 0.4 mm) having the flow path pattern as shown in FIG. A first flow path plate 10 made of SUS having a width of 5 mm, a width of 27 mm, and a thickness of 0.6 mm was prepared. After the first flow path plate 10 is laminated on the first intervening layer 11 of the joined body of the first vaporized fuel plate 99 / the first gas-liquid separation layer 12 / the first intervening layer 11 with a polyolefin adhesive, The joined body and the first flow path plate 10 were joined by pressure bonding.

(7) Production of First Fuel Battery Cell The MEA-current collecting layer laminate having the moisture retention layer produced above was laminated on the first vaporized fuel plate 99, 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 first fuel cell. A total of four first fuel cells (

first fuel cells

101a, 101b, 101c, 101d) were produced.

(8) Production of second fuel battery cell The same manner as above except that the first gas-liquid separation layer 12 is joined directly on the first flow path plate 10 without using the first intervening layer 11. Four fuel cells were produced and used as second fuel cells (

second fuel cells

102a, 102b, 102c, 102d).

(9) Fabrication of fuel distribution part The outer shape of polyphenylene sulfide (PPS) as shown in FIG. 12 (outer dimensions 56 mm, width 110 mm, height 50 mm), as shown in FIG. A fuel distributor 150 having an out-cell fuel flow path 155 with a different pattern was produced. An introduction port 151 is formed at the longitudinal center of the upper surface of the convex portion. The introduction port 151 is a through-hole that communicates with the trunk channel 152 of the out-cell fuel channel 155.

(10) Fabrication of planar integrated fuel cell As shown in FIG. 11, the four first fuel cells, the four second fuel cells, and the fuel distributor 150 are coupled (so that the screw holes are matched). A flat integrated fuel cell was produced. In order to prevent liquid leakage at the connection between the fuel flow path in 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. Performed (circles in FIG. 11 indicate screw holes).

(Evaluation of power generation characteristics of fuel cells)
A methanol aqueous solution with a methanol concentration of 20M is used as fuel, and fuel is supplied from the inlet 151 to the fuel flow path 155 outside the cell and further to the fuel flow path in the cell by using a liquid feed pump to generate power in the fuel cell. The change in the output voltage from the start of power generation to 2000 seconds after the start of power generation was measured. The extracted current value was gradually increased from the start of power generation, and was set to a constant current of 0.3 A from about 250 seconds after the start of power generation to about 1750 seconds after the start of power generation. The results are shown in FIG. As shown in FIG. 13, the eight fuel cells show a change pattern in which the output voltage value is almost the same when operating at a constant current of 0.3 A, and the fuel supply to each fuel cell is made uniform. As a result, it was confirmed that the variation in power generation between fuel cells was reduced.

DESCRIPTION OF SYMBOLS 1 1st electrolyte membrane, 1 '2nd electrolyte membrane, 2nd 1st anode pole, 2' 2nd anode pole, 1st cathode pole, 3 '2nd cathode pole, 4th 1st membrane electrode complex, 4'th 2 membrane electrode composite, 5 first anode current collecting layer, 5 'second anode current collecting layer, 6 first cathode current collecting layer, 6' second cathode current collecting layer, 7 first anode moisturizing layer, 7 'first 2 anode moisturizing layer, 8 first cathode moisturizing layer, 8 ′ second cathode moisturizing layer, 9,99 first vaporized fuel plate, 9 ′ second vaporized fuel plate, 9a, 99a first vaporized fuel storage part (through port) , 9a ′ second vaporized fuel storage portion, 9b, 99b first communication path, 10 first flow path plate, 10 ′ second flow path plate, 10a first in-cell fuel flow path, 10a ′ second in-cell fuel flow Road, 11 first intervening layer, 12 first gas-liquid separation layer, 12 ′ second Liquid separation layer, 13 second intervening layer, 99c, 99d first connection path, 100 fuel cell, 101, 101a, 101b, 101c, 101d, 901 first fuel cell, 102, 102a, 102b, 102c, 102d second Fuel cell, 110 fuel cell assembly, 150 fuel distributor, 151 inlet, 152 trunk channel, 153 branch channel, 155 external fuel channel.

Claims

A fuel cell including one or more first fuel cells and one or more second fuel cells arranged on the same plane,
The first fuel battery cell is
A first membrane electrode assembly having a first anode electrode, a first electrolyte membrane, and a first cathode electrode in this order;
A first flow path plate disposed on the first anode electrode side, wherein a first in-cell fuel flow path for circulating liquid fuel is disposed on the first anode electrode side surface;
A first gas-liquid separation layer disposed between the first membrane electrode assembly and the first flow path plate and capable of transmitting a vaporized component of the liquid fuel;
A first intervening layer disposed between the first gas-liquid separation layer and the first flow path plate so as to cover the first in-cell fuel flow path, and having a contact angle with respect to water of less than 70 degrees;
With
The second fuel battery cell is
A second membrane electrode assembly having a second anode electrode, a second electrolyte membrane, and a second cathode electrode in this order;
A second flow path plate disposed on the second anode pole side, wherein a second in-cell fuel flow path for circulating liquid fuel is disposed on the second anode pole side surface;
A second gas-liquid separation layer disposed on the second anode electrode side surface of the second flow path plate so as to cover the fuel flow path in the second cell, and capable of transmitting a vaporized component of the liquid fuel;
A fuel cell comprising:
The first fuel cell and the second fuel cell are arranged so that the supply flow rates of the liquid fuel to all the first in-cell fuel flow paths and the second in-cell fuel flow paths are substantially the same. The fuel cell according to claim 1.
Including at least one row of fuel cell assemblies in which one or more first fuel cells and one or more second fuel cells are arranged in a line;
2. The fuel cell according to claim 1, wherein a fuel cell disposed at at least one end of the fuel cell assembly is the first fuel cell.
4. The fuel cell according to claim 3, wherein the fuel cell assembly includes two first fuel cells arranged at both ends thereof and one or more second fuel cells.
A fuel distributor having an out-cell fuel channel connected to each of the first in-cell fuel channel and the second in-cell fuel channel and distributing the liquid fuel to each fuel cell of the fuel cell. The fuel cell according to claim 1, further comprising:
The fuel distributor has one inlet for introducing the liquid fuel,
The fuel cell according to claim 5, wherein the outside-cell fuel flow path includes a main flow path connected to the introduction port, and a branch flow path connecting the main flow path and each intra-cell fuel flow path.
The first fuel cell further includes a first anode current collecting layer laminated on the first anode electrode, and a first cathode current collecting layer laminated on the first cathode electrode,
The said 2nd fuel cell further contains the 2nd anode current collection layer laminated | stacked on the said 2nd anode electrode, and the 2nd cathode current collection layer laminated | stacked on the said 2nd cathode electrode. Fuel cell.
The fuel cell according to claim 1, which is a direct alcohol fuel cell.