JP2006134808A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell achieving both of the suppression of leakage of fuel gas and high exhausting performance of carbon dioxide and having high stability in power generation. <P>SOLUTION: The fuel cell is comprised of a power generation part 20 generating electric power with fuel gas and oxygen gas, an air supply part 30 supplying oxygen gas to an air electrode 21, a fuel supply part 40 installed so as to come in contact with the fuel electrode 23 of the power generation part 20 and supplying methanol gas formed by vaporizing a methanol aquous solution to the fuel electrode, a produced gas exhausting part 50 installed on both sides of the fuel supply part 40 and exhausting carbon dioxide gas produced in the fuel electrode 23 to the outside of the fuel cell 10, and others. The produced gas exhausting part 50 is comprised of a produced gas diffusion layer 51 connected to the side edge of a fuel gas diffusion layer 44, a gas separation membrane 52 installed so as to face the produced gas diffusion layer 51, and whose surface is exposed, and a produced gas exhausting hole 53 formed so as to open on the side surface 41b of a fuel electrode side housing 41. The gas separation membrane 52 permeates carbon dioxide gas selectively to methanol gas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell, and more particularly, to a fuel cell including a small, proton-conductive solid electrolyte layer.

  Nowadays, mobile terminal devices, particularly mobile phones, are provided with functions not only as a communication function but also as a video camera and a game machine. With such multi-functionality and high performance associated therewith, the power consumption of mobile phones has been increasing and the usage time has also been prolonged. Under such circumstances, it is required to increase the capacity of a battery that supplies power to a mobile phone.

  Currently, lithium ion secondary batteries are mounted on mobile phone batteries. In the lithium ion secondary battery, the increase in capacity in terms of material and structure is almost reaching its limit.

  On the other hand, direct methanol fuel cells (DMFC) are attracting attention as high-capacity power supplies. The DMFC theoretically has a capacity several times that of a lithium ion battery having the same volume. The DMFC uses a solid polymer electrolyte as an electrolyte, and generates electricity by supplying an organic fuel such as methanol directly onto an electrode. Since DMFC does not use a reformer that reforms organic fuel into hydrogen, it can be easily reduced in size and weight, and is therefore suitable as a power source for portable terminal devices.

In the DMFC, by supplying methanol and water in a liquid (methanol aqueous solution) state from the liquid fuel storage unit to the catalyst layer of the fuel electrode, protons (H ⁺ ), electrons (e ⁻ ), and carbon dioxide are generated on the catalyst. (Reaction formula: CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ ), protons permeate through the polymer solid electrolyte membrane and combine with oxygen in the catalyst layer of the oxidant electrode to generate water. At this time, electric power can be taken out by the generated electrons by connecting the fuel electrode and the oxidant electrode to an external circuit. The generated water is discharged from the air electrode to the outside of the system. On the other hand, carbon dioxide generated at the fuel electrode diffuses in the fuel liquid phase when liquid fuel is supplied directly to the cell, and is discharged out of the fuel cell system through a gas permeable membrane that allows only gas to permeate. .

  By the way, in a so-called liquid supply type DMFC that supplies an aqueous methanol solution directly to the fuel electrode, when methanol is consumed by power generation at the fuel electrode, the methanol concentration in the liquid fuel storage section gradually decreases. When the methanol concentration falls below a certain concentration, power generation stops and the methanol contained in the methanol aqueous solution cannot be used up.

  In order to solve this problem, a so-called vaporization supply type DMFC in which an aqueous methanol solution is vaporized and methanol is supplied to the catalyst layer of the fuel electrode in a gaseous state has been proposed (for example, see Patent Document 1). The vaporized supply type DMFC has an advantage that even if the methanol concentration in the liquid fuel storage unit is lowered, the methanol evaporates, so that power generation is possible and the methanol in the liquid fuel can be used up. That is, when the same volume of liquid fuel is used, the vaporized supply type DMFC provides a fuel cell with a higher capacity.

  By the way, in the vaporization supply type DMFC, the carbon dioxide gas generated at the fuel electrode increases the internal pressure on the fuel electrode side, so it is necessary to selectively discharge the carbon dioxide gas mixed with methanol gas to the outside.

1A is a plan view of the fuel cell of Patent Document 1, and FIG. 1B is a cross-sectional view of FIG. As shown in FIGS. 1A and 1B, in the fuel cell of Patent Document 1, the methanol aqueous solution is vaporized by the fuel holding layer 101, and the generated methanol gas is supplied to the fuel electrode 103 in contact with the solid electrolyte layer 102. Is done. The above reaction proceeds in the catalyst layer of the fuel electrode 103, and electrons generated by the reaction are taken out from the terminal 104 in contact with the fuel electrode 103. The terminal 104 is provided with a gas discharge port 105 and a liquid / gas separation membrane 106 for separating liquid and gas. Carbon dioxide gas generated at the fuel electrode 103 by liquid / gas separation is discharged to the outside.
JP 2002-289224 A

  However, Patent Document 1 discloses that the liquid / gas separation membrane 106 transmits carbon dioxide gas, but does not disclose the methanol gas barrier property of the liquid / gas separation membrane 106. When the liquid / gas separation membrane 106 does not shut off the methanol gas, the methanol gas leaks to the outside, causing a problem that the amount of generated power with respect to the supplied amount of methanol decreases. Further, since methanol gas is flammable, if it leaks excessively to the outside, there is a risk of fire such as ignition or explosion.

  Further, carbon dioxide gas is generated in the entire fuel electrode 103 by the above-described reaction. However, in Patent Document 1, the gas discharge port 105 is provided only in a part of the small area of the fuel electrode 103. In such a case, the internal pressure of the fuel cell is increased by the carbon dioxide gas that cannot be exhausted, and the evaporation of the fuel gas may be suppressed or the evaporation may be stopped. As a result, there is a risk of power generation being reduced and power generation being stopped. Further, the carbon dioxide gas discharge path from the fuel electrode 103 to the gas discharge port 105 has the same problem even when the permeation amount and permeation rate of the carbon dioxide gas are not ensured.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is a fuel that achieves both stable suppression of fuel gas leakage and high discharge capacity of carbon dioxide gas, and enables highly stable power generation operation. It is to provide a battery.

  According to one aspect of the present invention, an oxidant electrode to which an oxidant gas is supplied, a fuel electrode to which a fuel gas is supplied, and a solid electrolyte layer sandwiched between the oxidant electrode and the fuel electrode. A fuel gas supply unit comprising: a first gas diffusion layer for diffusing the fuel gas on the surface of the fuel electrode; and discharging a generated gas generated at the fuel electrode by a power generation reaction of the power generation unit. A generated gas discharge unit, wherein the generated gas discharge unit is connected to a side edge of the first gas diffusion layer, and the first gas diffusion layer is opposed to the second gas diffusion layer. A separation membrane having a surface and a second surface exposed to the outside of the fuel cell on a side opposite to the first surface, wherein the separation membrane selectively transmits the generated gas to the fuel gas. A fuel cell is provided.

  According to the present invention, in a fuel cell that generates power by introducing a fuel gas into a fuel electrode, the generated gas generated on the fuel electrode side is diffused into the side portion of the fuel cell via the first diffusion layer. A gas separation membrane that is diffused by the layer and selectively permeates the generated gas from the mixed gas of fuel gas, water vapor, and generated gas is provided opposite to the second gas diffusion layer. Since the gas separation membrane selectively permeates the generated gas, it is possible to suppress the leakage of the fuel gas and to prevent an increase in the internal pressure on the fuel electrode side due to the generation of the generated gas. As a result, a highly stable power generation operation is possible. Further, it is possible to realize a highly safe fuel cell by suppressing leakage of fuel gas to the outside.

  Further, according to the present invention, the second gas diffusion layer is provided so as to be in contact with the side edge of the first gas diffusion layer, and the separation membrane is disposed so as to face the second gas diffusion layer. Therefore, the separation membrane can secure a wide area in contact with the mixed gas. Therefore, the permeation rate of the product gas through the separation membrane can be improved, and the product gas discharge capacity can be improved. As a result, it is possible to realize a fuel cell that can further prevent the increase in internal pressure on the fuel electrode side and can generate power with high stability.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell which can suppress the leakage of fuel gas, raises the discharge | emission capability of a carbon dioxide gas, and can perform highly stable electric power generation operation can be provided.

  Embodiments of the fuel cell of the present invention will be specifically described below with reference to the drawings.

(First embodiment)
FIG. 2 is a plan view of the fuel cell according to the first example of the first embodiment of the present invention. Referring to FIG. 2, the fuel cell 10 according to the first example includes a housing 11, a laminated body including a power generation unit 20, an air supply unit 30, and a fuel supply unit 40 inside the housing 11, The generated gas discharge unit 50 is configured to discharge the carbon dioxide gas generated by the power generation reaction of the power generation unit 20 to the outside from the side surface of the fuel cell 10. As the liquid fuel, methanol, dimethyl ether (DME), ethanol, ethylene glycol, or the like can be used. In the following embodiments, a mixed solution of methanol and water or 100% concentration methanol (hereinafter abbreviated as “methanol aqueous solution”). )) As an example.

  FIG. 3 is a cross-sectional view of the fuel cell shown in FIG. Referring to FIG. 3, the fuel cell 10 includes an air supply unit 30 that supplies oxygen gas to the air electrode 21 on the air electrode 21 side of the power generation unit 20, and a liquid on the fuel electrode 23 side of the power generation unit 20. A fuel supply unit 40 that vaporizes the fuel and supplies a fuel gas such as methanol gas to the fuel electrode 23 is provided. Further, the generated gas discharge unit 50 is provided in the casing on both sides of the fuel supply unit 40 on the fuel electrode 23 side of the power generation unit 20.

  The power generation unit 20 includes an air electrode 21, a solid electrolyte layer 22, and a fuel electrode 23 stacked in this order. Further, the air electrode 21 and the fuel electrode 23 have an air electrode current collector 24 a and a fuel electrode current collection on the outside. An electric body 24b is provided.

  Although the air electrode 21 is not shown because it is a thin film, for example, the air electrode 21 is composed of a porous carbon paper and a catalyst layer made of Pt (platinum) fine particles on the carbon paper, and the catalyst layer becomes a solid electrolyte layer 22. Arranged to touch.

  The air electrode current collector 24a is made of a metal material having conductivity and high corrosion resistance such as Ni, SUS304, and SUS316. Moreover, the structure consists of a metal mesh, an expanded metal, a metal nonwoven fabric, a foam metal of a three-dimensional network structure, etc. so that air or oxygen gas can be introduce | transduced into the air electrode 21. FIG. Further, the air electrode current collector 24a is preferably formed on the surface thereof with a highly conductive and highly corrosion-resistant metal film, for example, an Au film. By providing such a metal film, it is possible to improve the corrosion resistance of the air electrode current collector 24a and reduce the contact resistance with the air electrode 21. The air electrode current collector 24 a is disposed in contact with the carbon paper of the air electrode 21.

  The solid electrolyte layer 22 is composed of a material having a proton conductive polymer solid electrolyte layer, for example, a polar group such as a strong acid group such as a sulfone group or a phosphate group, or a weak acid group such as a carboxyl group. For example, Nafion (registered trademark) NF117 (trade name, manufactured by DuPont) can be used for the solid electrolyte layer 22.

  The fuel electrode 23 is not shown because it is a thin film. For example, the fuel electrode 23 includes a porous carbon paper and a catalyst layer made of fine particles of Pt (platinum) -Ru (ruthenium) alloy on the carbon paper. The layer is disposed so as to contact the solid electrolyte layer 22.

  Like the air electrode current collector 24a, the fuel electrode current collector 24b is made of a metal material having conductivity and high corrosion resistance such as Ni, SUS304, and SUS316. Moreover, the structure consists of a metal mesh, an expanded metal, a metal nonwoven fabric, a foam metal of a three-dimensional network structure, etc. so that methanol gas and water vapor | steam can be introduce | transduced into the fuel electrode 23. FIG. Further, like the cathode current collector 24a, the anode current collector 24b is preferably formed on the surface thereof with a highly conductive and highly corrosion-resistant metal film such as an Au film.

In the catalyst layer of the fuel electrode 23, the oxidation reaction of CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ (reaction formula 1) proceeds, methanol gas and water vapor are consumed, carbon dioxide gas, proton (H ⁺ ), and Electrons are generated. The protons pass through the solid electrolyte layer 22 and reach the air electrode. The electrons reach the air electrode 21 through an external circuit (not shown) to which a load is connected as output power of the fuel cell. The carbon dioxide gas is discharged to the outside by a product gas discharge unit 50 described later. In the catalyst layer of the air electrode 21, the reduction reaction of 3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O (reaction formula 2) proceeds, and protons, electrons, and oxygen gas are consumed to generate water vapor. The water vapor is discharged to the outside through the air electrode gas diffusion layer 32 and the oxygen supply port 31a.

  The air supply unit 30 includes an air electrode side housing 31 and an air electrode gas diffusion layer 32 that diffuses oxygen introduced from the oxygen supply port 31a of the air electrode side housing 31 and introduces oxygen into the air electrode. The

  The air electrode side housing 31 is made of a resin material, and the resin material is not particularly limited. However, in terms of resistance to alcohol such as methanol, polyolefins such as polyethylene and polypropylene, fluororesins such as PTFE and PFA, and polyvinyl chloride. It is preferable to use a resin such as polybutylene terephthalate, polyethylene naphthalate, polyethersulfone, polysulfone, polyphenylene oxide, or polyetheretherketone.

  The air electrode side housing 31 is preferably provided with a large number of oxygen supply ports 31 a penetrating in the thickness direction so that oxygen is uniformly introduced into the entire air electrode gas diffusion layer 32.

  The air electrode gas diffusion layer 32 is made of a porous material and is not particularly limited as long as it is a porous material. Examples of suitable porous materials include ceramic porous materials, carbon paper, carbon fiber nonwoven fabrics, and fluororesin porous materials. And porous bodies such as a porous body and a polypropylene porous body.

  In the air supply unit 30, oxygen gas in the air is introduced from the oxygen supply port 31 a of the air electrode side housing 31, and the oxygen gas diffuses through the pores of the air electrode gas diffusion layer 32, and reaches the surface of the air electrode 21. Introduced. The air electrode gas diffusion layer 32 may not be provided when oxygen is sufficiently diffused by the surface of the air electrode, for example, carbon paper.

  The fuel supply unit 40 includes a fuel electrode side casing 41, a fuel storage unit 42 to which a methanol aqueous solution is supplied from, for example, a fuel tank (not shown), and a fuel vaporization film that vaporizes the methanol aqueous solution and converts it into methanol gas and water vapor. 43 and a fuel gas diffusion layer 44 for diffusing methanol gas and water vapor into the fuel electrode 23 on the fuel electrode 23 side of the fuel vaporization film 43.

  The fuel electrode side casing 41 is made of a resin material and is not particularly limited. However, like the air electrode side casing 31, in terms of resistance to alcohol such as methanol, polyolefins such as polyethylene and polypropylene, PTFE, and the like. Fluorine resins such as PFA, polyvinyl chloride, polybutylene terephthalate, polyethylene naphthalate, polyether sulfone, polysulfone, polyphenylene oxide, and polyether ether ketone are preferably used.

  The fuel storage unit 42 stores the aqueous methanol solution and introduces the aqueous methanol solution into the fuel vaporization film 43. As shown in FIG. 3, the fuel storage unit 42 is provided so as to face the fuel vaporization film 43, and the liquid fuel directly contacts the entire fuel vaporization film 43. Note that the fuel storage unit 42 may be provided so as to contact a part of the fuel vaporization film 43 in accordance with the degree of diffusion of the aqueous methanol solution in the fuel vaporization film 43.

  The fuel vaporization film 43 is made of a non-porous material made of a polymer having alcohol resistance such as methanol, or a porous material. In the fuel vaporization film 43, silicone rubber or the like is preferable as the non-porous material, and a porous material made of fluororesin is preferable as the porous material. When the fuel vaporized film 43 is a non-porous material, an aqueous methanol solution becomes a gas phase and permeates through the material. When the fuel vaporization film 43 is a porous material, the methanol aqueous solution that has passed through the pores is vaporized into methanol gas and water vapor on the surface on the fuel gas diffusion layer 44 side.

  The fuel gas diffusion layer 44 is made of a porous material having alcohol resistance such as methanol. Examples of the porous material suitable for the fuel gas diffusion layer 44 include porous materials such as ceramics, carbon paper, carbon fiber nonwoven fabric, fluororesin, and polypropylene.

  Further, the porosity of the fuel gas diffusion layer 44 is preferably set in a range of 30% to 95%, and more preferably set in a range of 40% to 90%. If the porosity exceeds 95%, the mechanical strength of the product gas diffusion layer 51 is lowered.

  The thickness of the fuel gas diffusion layer 44 is not particularly limited, but is preferably 1 mm or less. If the fuel gas diffusion layer 44 is thicker than 1 mm, the thickness of the entire fuel cell becomes excessively large.

  The fuel supply unit 40 introduces the methanol aqueous solution supplied to the fuel storage unit 42 into the fuel vaporization film 43. The fuel vaporization film 43 allows the methanol aqueous solution to pass through the pores by capillarity and On the fuel gas diffusion layer 44 side, the methanol aqueous solution is converted into methanol gas and water vapor by natural evaporation, and methanol gas and water vapor are introduced into the fuel gas diffusion layer 44. In the fuel gas diffusion layer 44, methanol gas and water vapor are diffused in the pores and introduced into the fuel electrode, and used in the reaction of the above-described reaction formula 1.

  The product gas discharge part 50 is provided on both sides of the fuel supply part 40 as shown in FIGS. The generated gas discharge unit 50 will be described in detail below.

  FIG. 4 is a cross-sectional view of a main part of the fuel cell according to the first example of the first embodiment. Referring to FIG. 4, the product gas discharge unit 50 is provided so as to be in contact with the product gas diffusion layer 51 and the product gas diffusion layer 51 provided so as to be in contact with the side edge of the fuel gas diffusion layer 44. The gas separation membrane 52 and the generated gas discharge hole 53 are formed so as to expose the surface of the gas separation membrane 52 and open to the side surface 41 b of the fuel electrode side housing 41.

  The generated gas diffusion layer 51 is made of a porous material having alcohol resistance such as methanol. Examples of the porous material suitable for the generated gas diffusion layer 51 include materials such as porous ceramics, carbon paper, carbon fiber nonwoven fabric, porous resin such as porous fluororesin and porous polypropylene, and the like. Nonwoven fabrics and porous resins are particularly preferred. The generated gas diffusion layer 51 diffuses carbon dioxide gas, methanol gas, and water vapor (hereinafter collectively referred to as “mixed gas”) generated at the fuel electrode 23 by reaction to the gas separation membrane 52 side. Let

  Moreover, it is preferable to set the thickness of the product gas diffusion layer 51 in the range of 200 μm to 1 mm. If the generated gas diffusion layer 51 is thinner than 200 μm, the carbon dioxide gas permeation rate decreases, and if it is thicker than 1 mm, the thickness of the entire fuel cell becomes excessively large.

  The generated gas diffusion layer 51 preferably has a higher porosity from the viewpoint of smoothly transmitting and diffusing the carbon dioxide gas generated at the fuel electrode 23, and the porosity is set in a range of 30% to 95%. It is preferable that it is set in the range of 30% to 90%. When the porosity exceeds 95%, the mechanical strength of the product gas diffusion layer 51 decreases.

  From the viewpoint of securing the mechanical strength of the fuel cell 10 together with the casing, the generated gas diffusion layer 51 preferably has a high mechanical strength. For example, a porous ceramic body such as an alumina porous membrane or a foam metal is used. be able to.

  The gas separation membrane 52 is provided opposite to and in contact with the surface 51a of the product gas diffusion layer 51. With this arrangement, the area where the gas separation membrane 52 contacts the mixed gas diffusing the product gas diffusion layer 51 can be increased. As a result, the permeation amount (so-called permeation rate) of carbon dioxide gas per unit time can be increased. Of course, the gas separation membrane 52 may be in contact with the side end face 51b of the product gas diffusion layer 51, but the area in contact with the mixed gas is reduced. For example, when the thickness of the product gas diffusion layer 51 is 0.3 mm and the gas separation film 52 is provided so as to be in contact with the side end surface 51b of the product gas diffusion layer, it faces the surface 51a of the product gas diffusion layer. A gas separation membrane 52 having a length of 6 mm is provided, and the length in the Y direction shown in FIG. 3 is similarly set. The ratio of the area of the gas separation membrane in contact with the mixed gas is 6 mm / 0.3 mm = 20, and the gas separation membrane area is 20 times larger when the gas separation membrane 52 is provided facing the surface 51a of the gas diffusion layer. Can be secured.

  The gas separation membrane 52 is preferably as large as the area facing the generated gas diffusion layer 51 is larger, and may be provided so as to cover almost the entire surface of the generated gas diffusion layer 51. That is, the shape of the gas separation membrane 52 is set such that the length in the Y direction of the fuel supply unit 40 shown in FIG. 2 and the length of the casing portion are substantially the same in the Y direction, and the generated gas diffusion layer shown in FIG. The length is set to the same length in the X direction except for the length in the X direction of 51 and the limitation of the housing portion. By setting in this way, the permeation rate of carbon dioxide gas through the gas separation membrane 52 can be further increased.

  The gas separation membrane 52 is pressed and fixed to the generated gas diffusion layer 51 side by the fuel electrode side casing 41. The method for fixing the gas separation membrane 52 is not limited to this, and an adhesive layer that fixes the gas separation membrane 52 to the generated gas diffusion layer 51 may be provided between the generated gas diffusion layer 51 and the gas separation membrane 52. Good. However, in this case, the mixed gas should not be leaked from the product gas diffusion layer 51 to the product gas discharge hole 53 side. Further, the gas separation membrane 52 may be provided so as to be separated from the product gas diffusion layer 51.

  The gas separation membrane 52 is made of a material that selectively transmits carbon dioxide gas from the mixed gas. That is, the gas separation membrane 52 has a function of selectively permeating carbon dioxide gas from the mixed gas diffused from the product gas diffusion layer 51 and releasing it to the outside. The gas separation membrane 52 is preferably made of a rubbery or glassy polymer in that carbon dioxide gas is selectively permeated from the mixed gas, and examples thereof include silicone rubber, polyimide, polyethersulfone, polysulfone, and polyamide. It is done.

  The gas separation membrane 52 is preferably made of a material having a carbon dioxide gas separation factor of 4 or more with respect to methanol gas. If this separation factor is 4 or more, a sufficient separation effect can be obtained. Further, this separation factor is preferably as high as possible, but is preferably 100 or less. The reason why the separation factor is set to 100 or less is that no material having a separation factor exceeding 100 has been found at present. Here, the separation factor is the ratio of the permeation rate of carbon dioxide gas to methanol gas. Specifically, one surface of the gas separation membrane 52 is contacted with a mixed liquid of carbon dioxide and methanol or a mixed gas thereof. Then, pressure was applied, and the component composition permeating the other surface of the gas separation membrane was measured and calculated. The separation factor is obtained by such a general method.

  From the viewpoint of the separation factor, for example, the polyimide film has a separation factor of 4 according to the study of the present inventor and is suitable as the gas separation membrane 52.

  The generated gas discharge hole 53 reaches the side surface of the fuel cell 10 from the surface of the gas separation membrane 52, that is, the side surface 41 b of the fuel electrode side housing 41, and discharges the carbon dioxide gas that has permeated the gas separation membrane 52 to the outside. .

  FIG. 5 is an enlarged view of a main part of a first modification of the product gas discharge unit of the first example. Referring to FIG. 5, the gas separation membrane 52 a is configured in the same manner as the generated gas discharge unit of the first example except that the gas separation membrane 52 a is provided so as to have irregularities in the thickness direction. While maintaining the separation factor of the carbon dioxide gas from the methanol gas of the gas separation membrane 52a, the substantial area of the gas separation membrane 52a can be increased to increase the permeation rate of the carbon dioxide gas. The unevenness of the gas separation membrane 52a is not particularly limited. For example, a circular or rectangular recess may be provided in the thickness direction of the gas separation membrane 52a, and the gas separation membrane 52a is folded in a pleated shape (so-called bellows shape). ) On the other hand, by providing the gas separation membrane 52a in this way, the gas separation membrane 52a can be miniaturized while maintaining the permeation rate of carbon dioxide gas, and as a result, the fuel cell 10 can be miniaturized.

  FIG. 6 is an enlarged view of a main part of a second modification of the product gas discharge unit of the first example. Referring to FIG. 6, the configuration is the same as the product gas discharge unit of the first example except that a porous membrane 55 is further provided outside the gas separation membrane 52 of the product gas discharge unit 50. The porous film 55 has a thickness of, for example, 300 μm, and the same material as the generated gas diffusion layer 51 can be used. The porous membrane 55 functions as a support for the gas separation membrane 52. In addition, the porous membrane 55 prevents the surface of the gas separation membrane 52 from being contaminated by foreign matter, organic gas, or the like that enters from the outside via the generated gas discharge hole 53. The generated gas discharge hole 53 may be filled with the porous film 55.

  FIG. 7 is an enlarged view of a main part of a third modification of the product gas discharge unit of the first example. Referring to FIG. 7, the configuration is the same as the product gas discharge unit of the first example except that the product gas discharge hole 53 a of the product gas discharge unit 50 is provided on the surface 41 a of the fuel electrode side housing 41. Since the surface 41a of the fuel electrode side housing 41 is easier to secure the area than the side surface 41b of the fuel electrode side housing 41, the generated gas discharge hole 53a is provided in this way, so that the first example shown in FIG. Compared to the above, the opening area of the product gas discharge hole 53a can be increased.

  FIG. 8 is an enlarged view of a main part of a fourth modification of the product gas discharge unit of the first example. Referring to FIG. 8, the fuel gas diffusion layer 44a is provided so as to be in contact with the gas separation membrane 52, and the configuration is the same as the product gas discharge unit of the first example except that the product gas diffusion layer is omitted. The fuel gas diffusion layer 44 a is made of the same material as the fuel gas diffusion layer 44 shown in FIG. 2 and is provided so as to extend in the side direction of the fuel cell so as to be in contact with the gas separation membrane 52. The fuel gas diffusion layer 44a supplies methanol gas to the fuel electrode 23 and diffuses the generated carbon dioxide gas. The carbon dioxide gas is discharged to the outside through the generated gas discharge hole 53 from the gas separation membrane 52 in contact with the fuel gas diffusion layer 44a. By integrating the product gas diffusion layer with the fuel gas diffusion layer 44a in this way, the diffusion of the mixed gas becomes smooth, the structure of the fuel cell is simplified, and the assembly of the fuel cell is facilitated.

  According to the present embodiment, in the fuel cell in which fuel gas is introduced into the fuel electrode to generate power, the carbon dioxide gas generated on the fuel electrode 23 side is diffused by the generated gas diffusion layer 51 in the side direction of the fuel cell 10. And a gas separation membrane 52 that selectively permeates carbon dioxide gas from a mixed gas composed of methanol gas, water vapor, and carbon dioxide gas is provided opposite the generated gas diffusion layer 51. Since the gas separation membrane 52 selectively transmits carbon dioxide gas, it is possible to suppress leakage of methanol gas and to prevent an increase in internal pressure on the fuel electrode 23 side due to generation of carbon dioxide gas. As a result, a highly stable power generation operation is possible. Further, since the gas separation membrane 52 selectively allows carbon dioxide gas to permeate from the mixed gas, leakage of methanol gas to the outside can be suppressed, and a highly safe fuel cell can be realized.

  Further, according to the present embodiment, the generated gas diffusion layer 51 is provided so as to be in contact with the side edge of the fuel gas diffusion layer 44, and the gas separation membrane 52 is disposed to face the generated gas diffusion layer 51. Therefore, the gas separation membrane 52 can ensure a wide area in contact with the mixed gas. Accordingly, the carbon dioxide gas permeation rate of the gas separation membrane 52 can be improved, and the carbon dioxide gas discharge capability can be improved. As a result, it is possible to realize a fuel cell that can further prevent the increase in internal pressure on the fuel electrode 23 side and can generate power with high stability.

  Further, since the produced gas diffusion layer 51 for inducing carbon dioxide gas is in contact with the fuel gas diffusion layer 44 or the produced gas diffusion layer 51 is integrated with the fuel gas diffusion layer 44, it is a carbon dioxide gas generation region. A discharge path from the fuel gas diffusion layer 44 in contact with the fuel electrode 23 to the gas separation membrane 52 that discharges carbon dioxide gas is formed. Since this discharge path has a wide cross-sectional area through which the mixed gas permeates, a high permeation rate of carbon dioxide gas can be secured. Therefore, the discharge capacity of carbon dioxide gas can be improved in terms of the transmission speed of carbon dioxide in the discharge path.

  In the first embodiment, the product gas discharge unit 50 is provided on both sides of the fuel supply unit 40. However, the product gas discharge unit 50 may be provided on either side of the fuel supply port 45 side, The product gas discharge unit 50 may be provided in a housing opposite to the supply port 45.

  Next, an example according to the first embodiment will be described.

[Example]
A fuel cell having the same configuration as that of the fuel cell shown in FIGS. 2 and 3 was formed. Further, only one of the two product gas discharge units is used, and the specific configuration of the product gas discharge unit is the same as that of the second modification of the first example shown in FIG. Specifically, the size of the power generation unit, the fuel gas diffusion layer, and the fuel vaporization film is 40 mm long × 40 mm wide, and the generated gas diffusion layer (length 10 mm × width) is in contact with the side surface of the fuel gas diffusion layer. 6 mm), and a gas separation membrane (length 10 mm × width 6 mm) and a porous membrane were laminated on the surface of the product gas diffusion layer. The fuel cell was evaluated by measuring the voltage and discharge time by setting the current value to 540 mA by the constant current discharge method.

  The following materials were used for the fuel cell.

[Power generation section]
Fuel electrode catalyst layer: Pt—Ru alloy supported catalyst TEC61E54 (Tanaka Kikinzoku Co., Ltd.)
Air electrode catalyst layer: platinum-supported catalyst TEC10E50E (Tanaka Kikinzoku Co., Ltd.)
Solid electrolyte layer: Solid electrolyte Nafion (registered trademark) NF117 (trade name, manufactured by DuPont) Fuel electrode current collector, air electrode current collector: mesh-like SUS304
[Fuel supply section]
Fuel: Methanol aqueous solution (methanol concentration 70% by volume)
Fuel vaporization membrane: Silicone rubber, thickness 50 μm, manufactured by Shin-Etsu Chemical Co., Ltd. Fuel gas diffusion layer: Carbon paper, thickness 280 μm, manufactured by Toray Industries, Inc. [Production gas discharge section]
Gas diffusion layer: carbon paper, thickness 280 μm, manufactured by Toray Industries, Inc. Gas separation membrane: silicone rubber, thickness 300 μm, manufactured by Shin-Etsu Chemical Co., Ltd. Porous membrane: porous fluororesin membrane, thickness 500 μm, manufactured by Sumitomo Electric Example "
The comparative example not according to the present invention had the same configuration as the example except that no gas separation membrane was provided. The fuel amount was the same as in the example.

  FIG. 9 is a diagram showing the relationship between the voltage and the discharge time of the fuel cells of Examples and Comparative Examples. Referring to FIG. 9, the fuel cell of the comparative example continued to generate power until about 38 minutes from the start of power generation, whereas the fuel cell of the example continued to generate power from about 57 minutes after the start of power generation. In the comparative example, since the gas separation membrane was not provided in the product gas discharge part, the power generation was stopped in a short time because methanol gas leaked together with the carbon dioxide gas, whereas the fuel cell of the example was removed from the product gas discharge part. This is probably because carbon dioxide gas was selectively discharged and there was little leakage of methanol gas.

  Therefore, according to Examples and Comparative Examples, by using silicone rubber for the gas separation membrane, leakage of methanol gas can be suppressed and carbon dioxide gas can be selectively discharged.

(Second Embodiment)
10A and 10B show a fuel cell according to a second embodiment of the present invention, in which FIG. 10A is a plan view thereof, and FIG. 10B is a sectional view taken along line BB of FIG. The fuel cell according to the second embodiment is a modification of the fuel cell according to the first embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIGS. 10A and 10B, a fuel cell 70 according to the second embodiment includes a power generation unit 20 that generates power using fuel gas and oxygen gas, an air supply unit 30, and a fuel supply unit. 40 and a pressure application unit 71 configured to apply pressure to the liquid fuel stored in the fuel storage unit 42 of the fuel supply unit 40, and the like, including a generated gas discharge unit 50 provided on both sides of the fuel supply unit 40, and the like. Except for the difference in the fuel vaporization film 73, it has the same configuration as the fuel cell according to the first example of the first embodiment shown in FIG.

  The fuel vaporization film 73 is formed of a non-porous film that is easy to permeate / move an aqueous methanol solution and that can easily release methanol gas and water vapor from its surface. As this non-porous film, perfluorosulfonic acid resin film (for example, Nafion (registered trademark) manufactured by DuPont, product name Aciplex manufactured by Asahi Kasei Co., Ltd.), perfluorocarbon resin film having a carboxyl group (For example, product name Flemion manufactured by Asahi Glass Co., Ltd.), silicone film (for example, trade name Katsuragi manufactured by Mitsubishi Plastics, Inc.), polyimide film, and the like can be used.

  The pressure application unit 71 applies a pressure (for example, a pressure of 0.1 MPa) to the liquid fuel stored in the fuel storage unit 42 by using an inert gas such as nitrogen gas or Ar gas. By applying pressure to the liquid fuel, the penetration of the liquid fuel into the fuel vaporization film 73 is promoted, and the amount of methanol gas supplied to the fuel gas diffusion layer 44 of the fuel vaporization film 73 is increased. Therefore, the methanol gas is smoothly supplied to the fuel electrode 23, and the power generation reaction can be stably maintained.

  According to the present embodiment, in addition to the effects of the first embodiment, the pressure application unit 71 applies pressure to the aqueous methanol solution to forcibly promote the supply of fuel gas from the fuel vaporization film 73. Thus, the power generation reaction can be stably maintained. Furthermore, since the pressure is applied even if the methanol aqueous solution decreases due to the continuation of the power generation reaction, the methanol aqueous solution penetrates into the fuel vaporization film 73. Therefore, a higher proportion of liquid fuel can be used than when no pressure is applied.

In addition, when using high concentration methanol aqueous solution or 100% concentration methanol for liquid fuel, water required for the catalyst layer of a fuel electrode may be insufficient. In this case, oxygen gas may be supplied to the fuel gas diffusion layer 44 to oxidize part of the methanol gas to generate water, and water may be supplied to the fuel electrode 23. That is, the reaction of CH ₃ OH + (3/2) O ₂ → CO ₂ + 2H ₂ O is considered to proceed on the surface of the catalyst layer of the fuel electrode 23, and the generated water is used in the catalyst layer. The carbon dioxide gas generated by this reaction is discharged to the outside through the same route as the carbon dioxide gas generated by power generation. Further, water generated by the reaction on the air electrode 21 side may be supplied to the fuel gas diffusion layer 44. These water supply methods may be applied not only to the fuel cell of the second embodiment but also to the fuel cell of the first embodiment.

  In addition, the first to fourth modifications of the product gas discharge unit of the first embodiment may be applied to the fuel cell of the second embodiment.

(Third embodiment)
FIG. 11 is a plan view of a fuel cell according to the third embodiment of the present invention. 12A is a schematic cross-sectional view taken along the line C-C of the fuel cell shown in FIG. 11, and FIG. 12B is an enlarged view of a portion D in FIG. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

11, 12 in reference (A) and the (B), the fuel cell 80, the fuel cell 81a 3 pieces each of the upper and lower side of the fuel reservoir section _{42 1 ~81a 3, 81b 1 ~81b} 3 Is arranged. Each fuel battery cell has the configuration of the cross-sectional view shown in FIG. 12B, and this configuration is the same as the fuel cell according to the first example of the first embodiment shown in FIG. The description is omitted.

In the fuel cell 80, each of the fuel cells 81a _{1 to} 81a ₃ , 81b _{1 to} 81b ₃ (hereinafter, when it is not necessary to specify the fuel cell, the symbol is “81”). Are electrically connected in series. For example, the upper three fuel cells 81a _{1 to} 81a ₃ are arranged from the left side of the figure, the fuel electrode of the fuel cell 81a ₁ , the air electrode of the fuel cell 81a ₂ adjacent to the right side, and the fuel cell 81a ₂ . The fuel electrode and the air electrode of the fuel cell 81 a ₃ adjacent to the right side of the fuel electrode are connected by a lead wire 82. Further, three fuel cell 81b ₁ ~81b ₃ and the lower from the left side of the figure, the fuel electrode of the fuel cell 81b ₂ adjacent fuel cell 81b ₁ of the air electrode and on the right side, the fuel cell 81b ₂ The fuel electrode of the fuel cell 81 b ₃ adjacent to the right side of the air electrode is connected by a lead wire 82. Further, the fuel electrode of the upper fuel cell 81 a _{3 and} the air electrode of the lower fuel cell 81 b ₃ are connected by a lead wire 82. With this connection, by the upper fuel cell 81a ₁ of the air electrode and the lower side of the fuel cell 81b ₁ of the output terminal 83a of each connecting fuel cell to the cathode, to 83b connecting the load A total output voltage obtained by adding the output voltages of the respective fuel cells 81 is obtained. For example, although the output voltage of one fuel cell 81 is about 0.4V depending on the output current, a total output voltage of 2.4V can be obtained by connecting six fuel cells 81. . The lead wire 82 may be provided at the boundary between adjacent fuel cells 81 or may be provided on the side surface of the fuel cell 80. The lead wire 82 may be any of an electrically connectable conductive wire, plate, and wiring pattern. The connection pattern of the fuel cells 81 is not limited to this, and as described above, the upper three fuel cells 81a _{1 to} 81a ₃ and the lower three fuel cells 81b _{1 to} 81b ₃ are electrically connected to each other. the series connection, further, may be connected to the fuel cell 81b ₁ ~81b ₃ of the upper fuel cell in series connected cell 81a ₁ ~81a ₃ and the lower electrically in parallel.

As shown in FIG. 11, in the fuel cell, the product gas discharge parts 50a _{1 to} 50a ₃ , 50b _{1 to} 50b ₃ (hereinafter, when the product gas discharge part does not need to be specified, the symbol is “50”. ) Are provided on both sides of the fuel cell 81, and its specific structure is the same as that of the first example of the first embodiment shown in FIG. Therefore, a sufficient area of the gas separation membrane 52 of the generated gas discharge unit 50 can be secured. Furthermore, since the fuel cells 81 can be arranged close to each other, the lead wires 82 connecting the adjacent fuel cells 82 can be shortened, and the electric resistance value between the fuel cells 82 can be reduced.

  In addition, although the fuel cell 81 is provided on both the upper and lower surfaces of the fuel storage unit 42, the generated gas discharge holes 53 do not interfere with each other because the generated gas discharge holes 53 are provided on the side surfaces of the fuel cell. In addition, you may comprise the product gas discharge part 50 of this Embodiment similarly to the 1st modification of the product gas discharge part shown in FIG. 5 and FIG. 6, and a 2nd modification.

  According to the present embodiment, in the fuel cell composed of the plurality of fuel cells 81, by providing the generated gas discharge portions 50 on both sides of each fuel cell 81, a high output voltage can be obtained and the fuel cell 80 can be obtained. The carbon dioxide emission capacity can be improved while suppressing the increase in size. As a result, a fuel cell capable of highly stable power generation operation can be realized.

In addition, the produced gas discharge portions 50 of the respective fuel cells 81 may be connected to each other. For example, the product gas diffusion layer 51 and the gas separation membrane 52 connected to the upper three fuel cells 81a _{1 to} 81a ₃ are respectively integrated. By doing so, the area of the gas separation membrane 52 can be further increased. In this case, however, an insulating material should be used for the product gas diffusion layer 51. The lower three fuel cells 81b _{1 to} 81b ₃ may be configured similarly.

  In addition, the product gas discharge part 50 may be provided only on one side of the fuel cell 81, and the product gas discharge part is provided in the casing on the fuel supply port 45 side or the casing on the opposite side to the fuel supply port 45. 50 may be further provided.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention described in the claims. It can be changed.

In addition, the following additional notes are disclosed regarding the above description.
(Appendix 1) An oxidant electrode to which an oxidant gas is supplied;
A fuel electrode to which fuel gas is supplied; and
A power generation unit comprising a solid electrolyte layer sandwiched between the oxidant electrode and the fuel electrode;
A fuel gas supply unit comprising: a first gas diffusion layer for diffusing the fuel gas on the surface of the fuel electrode;
A product gas discharge unit for discharging the generated gas generated at the fuel electrode by the power generation reaction of the power generation unit,
The product gas discharge unit
A second gas diffusion layer connected to a side edge of the first gas diffusion layer;
A separation membrane having a first surface facing the second gas diffusion layer and a second surface exposed to the outside of the fuel cell on the opposite side of the first surface;
The fuel cell, wherein the separation membrane selectively transmits the generated gas with respect to the fuel gas.
(Supplementary Note 2) The fuel gas supply unit
A liquid fuel storage unit for storing liquid fuel;
The fuel cell according to claim 1, further comprising a vaporization film that converts the liquid fuel supplied from the liquid fuel storage unit into fuel gas and supplies the fuel gas to the first gas diffusion layer.
(Supplementary Note 3) The second gas diffusion layer is disposed substantially on the same surface as the first gas diffusion layer, and the separation membrane is disposed over substantially the entire surface of the second gas diffusion layer. The fuel cell according to Supplementary Note 1 or 2, which is characterized.
(Supplementary note 4) The fuel cell according to any one of Supplementary notes 1 to 3, wherein the second gas diffusion layer is made of the same material as the first gas diffusion layer.
(Additional remark 5) The said 2nd gas diffusion layer is integrated with the 1st gas diffusion layer, The fuel cell of Additional remark 4 characterized by the above-mentioned.
(Appendix 6) The second gas diffusion layer is made of any one of a group consisting of porous ceramics, carbon paper, carbon fiber nonwoven fabric, porous fluororesin, and porous polypropylene. The fuel cell according to any one of supplementary notes 1 to 5.
(Additional remark 7) The said separation membrane consists of rubber-like or glassy polymer, The fuel cell as described in any one of Additional remarks 1-6 characterized by the above-mentioned.
(Supplementary note 8) The fuel cell according to any one of supplementary notes 1 to 7, wherein the separation membrane has a separation factor of the produced gas with respect to the fuel gas of 4 or more.
(Additional remark 9) The said separation membrane itself is formed in uneven | corrugated shape along the thickness direction, The fuel cell as described in any one of Additional remarks 1-8 characterized by the above-mentioned.
(Supplementary note 10) The fuel cell according to any one of supplementary notes 7 to 9, further comprising a porous membrane on the second surface of the separation membrane.
(Additional remark 11) The said generated gas discharge part is further equipped with the generated gas discharge hole opened to the exterior of the said fuel cell in the 2nd surface side of the said separation membrane, Of additional remarks 1-10 characterized by the above-mentioned. The fuel cell according to any one of claims.
(Additional remark 12) The said production gas discharge hole is formed in the side surface of the said fuel cell, The fuel cell of Additional remark 11 characterized by the above-mentioned.
(Supplementary note 13) The fuel cell according to any one of supplementary notes 1 to 12, wherein a plurality of generated gas discharge portions are arranged around the fuel gas supply portion.
(Supplementary note 14) The fuel cell according to supplementary note 13, wherein the second gas diffusion layers of each of the plurality of product gas discharge portions are connected to each other.
(Supplementary Note 15) A power generation unit including an oxidant electrode to which an oxidant gas is supplied, a fuel electrode to which fuel gas is supplied, and a solid electrolyte layer sandwiched between the oxidant electrode and the fuel electrode,
A plurality of fuel cells having a fuel gas supply section comprising a first gas diffusion layer for diffusing the fuel gas on the surface of the fuel electrode;
A liquid fuel storage unit for storing liquid fuel;
A product gas discharge unit that discharges a product gas generated at the fuel electrode by a power generation reaction of the power generation unit;
The plurality of fuel cells are disposed along a first direction on at least one surface of the liquid fuel storage unit,
The product gas discharge unit
Arranged on at least one side of a second direction orthogonal to the first direction of each fuel cell;
A second gas diffusion layer connected to a side edge of the first gas diffusion layer;
A separation membrane having a first surface facing the second gas diffusion layer and a second surface exposed to the outside of the fuel cell on the opposite side of the first surface;
The fuel cell, wherein the separation membrane selectively permeates the generated gas with respect to the fuel gas.
(Supplementary Note 16) The product gas discharge part further includes a product gas discharge hole on the second surface side of the separation membrane,
16. The fuel cell according to appendix 15, wherein the generated gas discharge hole is formed in a side surface of the fuel cell.

(A) is a top view of the conventional fuel cell, (B) is sectional drawing of (A). It is a top view of the fuel cell which concerns on the 1st example of the 1st Embodiment of this invention. FIG. 3 is a cross-sectional view of the fuel cell shown in FIG. It is principal part sectional drawing of the fuel cell which concerns on the 1st example of 1st Embodiment. It is a principal part enlarged view of the 1st modification of a generated gas discharge part. It is a principal part enlarged view of the 2nd modification of a product gas discharge part. It is a principal part enlarged view of the 3rd modification of a product gas discharge part. It is a principal part enlarged view of the 4th modification of a generated gas discharge part. It is a figure which shows the relationship between the voltage of the fuel cell of an Example and a comparative example, and discharge time. The fuel cell which concerns on the 2nd Embodiment of this invention, (A) is the top view, (B) is the BB sectional drawing of (A). It is a top view of the fuel cell which concerns on the 3rd Embodiment of this invention. (A) is CC sectional typical sectional drawing of the fuel cell shown in FIG. 11, (B) is the D section enlarged view of (A).

Explanation of symbols

10, 70, 80 Fuel cell 20 Power generation unit 21 Air electrode 22 Solid electrolyte layer 23 Fuel electrode 24a Air electrode current collector 24b Fuel electrode current collector 30 Air supply unit 31 Air electrode side casing 31a Oxygen supply port 32 Air electrode gas diffusion layer 40 fuel supply unit 41 the fuel electrode side casing 41b fuel electrode side casing side 42 fuel storage portion 43 fuel vaporization layer 44 fuel gas diffusion layer _{50,50a 1 ~50a 3, 50b 1 ~50b} 3 product gas discharge section 51 Product Gas Diffusion Layer 52 Gas Separation Membrane 53, 53a Product Gas Discharge Hole 71 Pressure Application Unit 73 Fuel Evaporation Membrane (Nonporous Membrane)
81, 81a _{1 to} 81a ₃ , 81b _{1 to} 81b ₃ fuel cells

Claims (5)

An oxidant electrode to which an oxidant gas is supplied;
A fuel electrode to which fuel gas is supplied; and
A power generation unit comprising a solid electrolyte layer sandwiched between the oxidant electrode and the fuel electrode;
A fuel gas supply unit comprising: a first gas diffusion layer for diffusing the fuel gas on the surface of the fuel electrode;
A product gas discharge unit that discharges a product gas generated at the fuel electrode by a power generation reaction of the power generation unit;
The product gas discharge unit
A second gas diffusion layer connected to a side edge of the first gas diffusion layer;
A separation membrane having a first surface facing the second gas diffusion layer and a second surface exposed to the outside of the fuel cell on the opposite side of the first surface;
The fuel cell, wherein the separation membrane selectively transmits the generated gas with respect to the fuel gas.   The second gas diffusion layer is disposed substantially on the same plane as the first gas diffusion layer, and the separation membrane is disposed over substantially the entire surface of the second gas diffusion layer. Item 2. The fuel cell according to Item 1.   3. The fuel cell according to claim 1, wherein the separation membrane is made of a rubbery or glassy polymer.   The fuel cell according to any one of claims 1 to 3, wherein the separation membrane has a separation factor of the produced gas with respect to the fuel gas of 4 or more. A power generation unit including an oxidant electrode to which an oxidant gas is supplied, a fuel electrode to which a fuel gas is supplied, and a solid electrolyte layer sandwiched between the oxidant electrode and the fuel electrode;
A plurality of fuel cells having a fuel gas supply section comprising a first gas diffusion layer for diffusing the fuel gas on the surface of the fuel electrode;
A liquid fuel storage unit for storing liquid fuel;
A product gas discharge unit that discharges a product gas generated at the fuel electrode by a power generation reaction of the power generation unit;
The plurality of fuel cells are disposed along a first direction on at least one surface of the liquid fuel storage unit,
The product gas discharge unit
Arranged on at least one side of a second direction orthogonal to the first direction of each fuel cell;
A second gas diffusion layer connected to a side edge of the first gas diffusion layer;
A separation membrane having a first surface facing the second gas diffusion layer and a second surface exposed to the outside of the fuel cell on the opposite side of the first surface;
The fuel cell, wherein the separation membrane selectively transmits the generated gas with respect to the fuel gas.

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