JP2010135156A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of facilitating miniaturization. <P>SOLUTION: In the fuel cell formed by laminating a plurality of electrolyte integrated electrodes, a separator 10 arranged between the two adjacent electrolyte integrated electrodes of two adjacent electrodes is a square in a planar view, and consists of one sheet. A fuel supply manifold 11 is formed in the vicinity of one side among four sides forming the square on the separator, and a fuel discharge manifold is formed in the vicinity of the other side facing to the one side. A plurality of oxygen passages for connecting two sides different from two opposite sides where the fuel supply manifold and the fuel discharge manifold are formed are formed parallel to each other or approximately parallel to each other on one surface of the separator, and the other surface of the separator is planar. The surface of the separator having the oxygen passage comes in contact with a positive electrode of the electrolyte integrated electrode, and the other planar surface comes in contact with a negative electrode 25 of the electrolyte integrated electrode adjacent to the electrolyte integrated electrode 20a via the separator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell that can be easily downsized.

  In recent years, with the widespread use of cordless devices such as personal computers and mobile phones, batteries that are power sources are increasingly required to be smaller and have higher capacities. Currently, lithium ion secondary batteries have been put into practical use as batteries that have high energy density and can be reduced in size and weight, and demand for portable power sources is increasing. However, this lithium ion secondary battery has a problem that it cannot guarantee a sufficient continuous use time for some cordless devices.

  Development of fuel cells such as a polymer electrolyte fuel cell (PEFC) has been promoted to solve the above problems. The fuel cell can be used continuously if fuel and oxygen are supplied. A PEFC that uses a solid polymer electrolyte as an electrolyte, oxygen in the air as a positive electrode active material, and fuel as a negative electrode active material has attracted attention as a battery having a higher energy density than a lithium ion secondary battery.

  In general PEFC, a plurality of electrode / electrolyte integrated bodies (MEAs) including a positive electrode, a negative electrode, and a solid polymer electrolyte membrane disposed between them are laminated, and each MEA has an oxygen flow. They are stacked in a state of being sandwiched between two types of separators, a positive electrode side separator that forms a channel (oxidant channel) and a negative electrode side separator that forms a fuel channel. Also, a flow path for circulating a cooling medium is generally formed between the negative electrode side separator and the positive electrode side separator. That is, normally, three flow paths, that is, an oxygen flow path, a cooling medium flow path, and a fuel flow path, are formed in the MEA stacking direction within a pair of separators.

  Since the oxygen flow path, the cooling medium flow path, and the fuel flow path are usually formed by providing grooves on the surface of the separator, each separator needs to have a certain thickness. A fuel cell configured by stacking a plurality of MEAs sandwiched in between is bulky.

  Further, the separator requires a fuel supply manifold, a fuel discharge manifold, an oxygen supply manifold, an oxygen discharge manifold, a cooling medium supply manifold, and a cooling medium discharge manifold that penetrate in the stacking direction (for example, Patent Document 1). The electrode overlapped with the separator needs to have a portion that can directly participate in power generation in a region other than the position corresponding to each of the manifold forming portions, and the area of the portion that can directly participate in power generation is sufficiently large. I can't take it.

  On the other hand, Patent Document 2 proposes a fuel cell having a structure in which an oxygen channel and a cooling medium channel are shared. In the fuel cell described in Patent Document 2, a plurality of oxygen flow paths are formed in a straight line from one end to the opposite end on the surface of the separator in contact with the positive electrode. Both ends are exposed to the outside of the separator. And external air is supplied in an oxygen flow path using a fan. Oxygen in the air supplied into the oxygen channel acts as an oxidant, and the air itself acts as a cooling medium. Therefore, since the acid path channel also serves as the cooling medium channel, it is not necessary to separately form the cooling medium channel, and the fuel cell can be made compact.

JP 2006-310288 A JP 2006-86127 A

  However, the fuel cell described in Patent Document 2 is also insufficient for miniaturization because the fuel flow path is formed in the negative electrode separator.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fuel cell that can be easily downsized.

  The fuel cell of the present invention capable of achieving the above object is disposed between a positive electrode having a positive electrode catalyst layer for reducing oxygen, a negative electrode having a negative electrode catalyst layer for oxidizing fuel, and the positive electrode and the negative electrode. A fuel cell comprising a solid polymer electrolyte membrane and a plurality of electrode / electrolyte integrals having a quadrangular shape in plan view, with a separator interposed between two adjacent electrode / electrolyte integrals The separator disposed in the shape of the separator is a quadrangular shape in plan view, and is composed of one sheet, and the positive electrode, the negative electrode, the solid polymer electrolyte membrane, and the separator have four sides that form a quadrangle. A fuel supply manifold is formed in the vicinity of one side, a fuel discharge manifold is formed in the vicinity of the other side opposite to the one side, and the fuel supply manifold and the fuel discharge are formed on one surface of the separator. A plurality of oxygen passages that linearly connect two sides other than the two opposite sides on which the nihold is formed are formed in parallel or substantially in parallel to each other, and the other surface of the separator is planar. The separator has a surface having an oxygen channel in contact with the positive electrode of the electrode / electrolyte integrated product, and the other planar surface of the electrode / electrolyte integrated product is adjacent to the electrode / electrolyte integrated product through the separator. It is characterized by being in contact with the negative electrode.

  According to the present invention, it is possible to provide a fuel cell that can be easily downsized.

  FIG. 1 is a perspective view schematically showing an example of the fuel cell of the present invention. A fuel cell 100 shown in FIG. 1 includes a plurality of electrode / electrolyte integrated bodies (hereinafter referred to as “MEA”) 20 stacked via a separator 10, and both ends of the stacked MEA 20 group are end plates 50, 50, and is fixed with bolts and nuts. In FIG. 1, 60 is a fuel supply port, and 70 is a fuel discharge port. Fuel is introduced into the fuel cell from the fuel supply port 60, supplied to the negative electrode of each MEA 20, and used for power generation. Then, the fuel that has not been consumed by each MEA 20 is discharged from the fuel discharge port 70 to the outside of the fuel cell.

  2 is an exploded view of the main part of the fuel cell of FIG. 1, and FIG. 3 is a cross-sectional view of the main part of the fuel cell of FIG. In the figure, 20a is a laminate in which a positive electrode catalyst layer (22 in FIG. 3), a solid polymer electrolyte membrane (23 in FIG. 3), and a negative electrode catalyst layer (24 in FIG. 3) are laminated in this order from the top. The positive electrode diffusion layer 21 is disposed on the upper side and the negative electrode diffusion layer 25 is disposed on the lower side to constitute the MEA. Separators 10 and 10 are disposed above and below the MEA. Although FIG. 3 is a cross-sectional view, for the purpose of facilitating understanding of the fuel flow path formed by the fuel supply manifold and the fuel discharge manifold of each component, the upper end of the upper separator 10 and the lower The back portion is omitted except for the lower end of the separator 10.

  The separators 10 and 10 are formed with a fuel supply manifold 11 and a fuel discharge manifold 12. The separators 10 and 10 have a quadrangular shape in plan view, and each is composed of one sheet. The fuel supply manifold 11 is formed in the vicinity of one of the four sides forming the quadrangle, and the fuel discharge manifold 12 is formed in the vicinity of the one side facing the one side.

  Moreover, the separators 10 and 10 are formed with a plurality of groove-like oxygen channels 13 on one side and the other side is flat. The oxygen flow paths 13 of the separators 10 and 10 are parallel or substantially parallel to each other so that the fuel supply manifold 11 and the fuel discharge manifold 12 are linearly connected to two sides other than the opposing two sides formed in the vicinity. Is formed.

  Further, in the positive electrode catalyst layer, the solid polymer electrolyte, and the negative electrode catalyst layer related to the laminate 20a, the fuel supply manifold is located at a position corresponding to the fuel supply manifold 11 of the separators 10 and 10, and the fuel discharge manifold 12 is located. Each fuel discharge manifold is formed.

  The positive electrode diffusion layer 21 is disposed so as to cover the entire surface of the oxygen channel 13 forming portion in the upper separator 10. A positive electrode gas seal 30 for suppressing the outflow of fuel gas is disposed outside the two sides of the positive electrode diffusion layer 21 that are parallel or substantially parallel to the oxygen flow path 13 of the separator 10. A fuel supply manifold is formed at a position corresponding to the fuel supply manifold 11 of the separators 10 and 30, and a fuel discharge manifold is formed at a position corresponding to the fuel discharge manifold 12.

  Further, the negative electrode diffusion layer 25 is in contact with the flat plate surface of the lower separator 10, and a negative electrode gas seal 40 for suppressing the outflow of fuel gas is disposed outside the outer periphery thereof. A fuel supply manifold is formed at a position corresponding to the fuel supply manifold 11 of the separators 10 and 10 of the negative electrode gas seal 40, and a fuel discharge manifold is formed at a position corresponding to the fuel discharge manifold 12.

  2 and 3, the flow of air containing oxygen is indicated by a dotted arrow, and the flow of fuel gas is indicated by a solid arrow. The fuel introduced from the fuel supply manifold 11 is supplied to the negative electrode catalyst layer 24 through the negative electrode diffusion layer 25. Then, the fuel that is not involved in the power generation reaction and not consumed is discharged from the fuel discharge manifold 12 to the outside through the negative electrode diffusion layer 25.

  Further, the oxygen flow path 13 included in the separators 10 and 10 is formed so as to linearly connect two opposing sides of the quadrangular separator in a plan view, and both ends thereof are open on the side surface of the separator. Yes. Therefore, for example, air is introduced into the oxygen channel 13 by sending air containing oxygen from the side surface of the fuel cell (the side surface of the separator 10 where the oxygen channel 13 is open) using a fan or the like. The The air (oxygen) introduced into the oxygen flow path 13 is supplied to the positive electrode catalyst layer 22 through the positive electrode diffusion layer 21 of MEA. In addition, oxygen that is not involved in the power generation reaction and that is not consumed and components other than oxygen in the air are open ends of the oxygen flow path 13 on the side surface of the fuel cell (the side surface opposite to the side on which air is fed). Is discharged to the outside.

  As will be described in detail later, the negative electrode diffusion layer related to the negative electrode is generally composed of a material through which fuel can flow, such as a water-repellent porous carbon sheet. Therefore, in the fuel cell of the present invention, for example, when the fuel supply pressure is relatively low, the fuel introduced from the fuel supply manifold is supplied to the negative electrode catalyst layer through the holes in the negative electrode diffusion layer and consumed. The remaining fuel is discharged from the fuel discharge manifold through the hole in the negative electrode diffusion layer. Therefore, as shown in FIGS. 2 and 3, the separator interposed between adjacent MEAs only needs to have an oxygen flow path, and it is not necessary to form a fuel flow path. The separator can be made thin. Therefore, the fuel cell of the present invention can have a compact structure.

  Further, when the fuel cell of the present invention is used, for example, in a state where the fuel supply pressure is relatively high, the fuel supply manifold and the fuel discharge manifold are linearly arranged on the surface of the negative electrode diffusion layer, as will be described later. Preferably, a plurality of groove-like fuel flow paths connected in a shape may be formed in parallel or substantially in parallel.

  In the fuel cell shown in FIGS. 2 and 3, the air passing through the oxygen channel 13 also acts as a cooling medium. Therefore, since the oxygen flow path 13 also serves as the cooling medium flow path, there is no need to separately form a cooling medium flow path in the separator. Therefore, the separator is formed of a single layer, and the separator is made flat on one side. Even if it is thin, cooling with a cooling medium is possible.

  Details of the separator 10 shown in FIG. 2 are shown in FIG. 4A is a plan view of the surface side where the oxygen flow path 13 is not formed, FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A, and FIG. 4C is a view where the oxygen flow path 13 is formed. It is a top view of the surface side.

  In the separator 10, the fuel supply manifold 11 and the fuel discharge manifold 12 are arranged in the vicinity of two opposite sides of the four sides forming a quadrangle in a plan view. The fuel supply manifold and fuel discharge manifold of the separator are arranged as described above, and the fuel supply manifold and fuel discharge manifold formed on the positive electrode, negative electrode and solid polymer electrolyte membrane of the MEA are connected to the fuel supply manifold and fuel discharge manifold of the separator. By forming it in the corresponding position, the area where the fuel in the negative electrode can flow well, that is, the area sandwiched between the fuel supply manifold and the fuel discharge manifold can be made larger, and the electrode area that can be well involved in power generation Can be made larger, and more efficient power generation can be achieved. For example, in a fuel cell using hydrogen as a fuel, water generated during power generation or water contained in the fuel may stay in the negative electrode and hinder the subsequent power generation reaction. However, by disposing the fuel supply manifold and the fuel discharge manifold as described above, the flow of fuel can be linearly directed from the fuel supply manifold to the fuel discharge manifold at almost all points of the negative electrode. Water can be discharged to the outside through the fuel discharge manifold, and a decrease in power generation efficiency due to water remaining in the negative electrode can be suppressed.

  Further, one side of the separator 10 is planar [FIG. 4 (a)], and on the other side [FIG. 4 (c)], as described above, of the four sides constituting a quadrangle in plan view, the fuel supply A plurality of oxygen flow paths 13 that linearly connect two sides other than the two opposite sides on which the manifold 11 and the fuel discharge manifold 12 are formed are formed in parallel or substantially parallel to each other. The oxygen channel 13 has a groove shape, and ribs 14 exist between adjacent oxygen channels. In (c), in order to make it easy to distinguish the oxygen flow path 13 and the rib 14, the oxygen flow path 13 is shown with dots. In the oxygen flow path related to the separator, “parallel to or substantially parallel to each other” basically means that the respective oxygen flow paths are formed in parallel to each other. It is an acceptable meaning as long as the effect is not impaired.

  The length in the oxygen flow path direction of the separator [the length in the vertical direction in FIGS. 4A and 4C] is preferably 10 mm or more from the viewpoint of sufficiently securing the electrode area. In addition, as described above, the air passing through the oxygen channel can be used as a cooling medium in addition to supplying oxygen (oxidant), but the length of the separator in the oxygen channel direction is too long. Then, there is a possibility that the heat generated during power generation of the fuel cell cannot be sufficiently cooled by the air passing through the oxygen flow path. Therefore, the length of the separator in the oxygen flow path direction is preferably 100 mm or less.

  The distance between the fuel supply manifold and the fuel discharge manifold in the separator (the shortest distance; the same applies to the distance between the fuel supply manifold and the fuel discharge manifold) is 10 mm from the viewpoint of securing a sufficient electrode area. The above is preferable. Further, if the distance between the fuel supply manifold and the fuel discharge manifold is too long, the fuel flow path becomes long, and the pressure loss of the fuel flow may increase. For this reason, the distance between the fuel supply manifold and the fuel discharge manifold in the separator is preferably 300 mm or less.

  The width of the fuel supply manifold and the fuel discharge manifold in the separator [the length in the lateral direction in FIGS. 4A and 4C] can secure the gas sealability described later in order to reduce the pressure loss during fuel flow. It is preferable to make it as large as possible within the range.

  The fuel supply manifold and the fuel discharge manifold are provided in the vicinity of two opposite sides of the four sides of the rectangular separator in plan view. Specifically, the fuel supply manifold is shown in FIG. And in (c), it is preferable to arrange | position so that the distance from the vertical side of the left side may become as short as possible in the range which can ensure the gas-sealing property mentioned later. In addition, it is preferable that the distance from the vertical side on the right side of the fuel discharge manifold is as short as possible within a range in which gas sealing performance described later can be secured in FIGS. 4 (a) and 4 (c).

  In the fuel cell according to the present invention, the fuel supply manifold and the fuel discharge manifold formed on the positive electrode, the negative electrode, and the solid polymer electrolyte membrane of the MEA are disposed at locations corresponding to the positions of the fuel supply manifold and the fuel discharge manifold of the separator. . Thereby, the fuel supply manifold of the separator and the MEA overlaps, and the fuel discharge manifold of the separator and the MEA overlaps to form a fuel flow path in the thickness direction of the fuel cell (the stacking direction of the separator and the MEA).

  In determining the positions of the fuel supply manifold and fuel discharge manifold of the positive electrode, negative electrode, and solid polymer electrolyte membrane of the MEA, and the fuel supply manifold and fuel discharge manifold of the separator, the positive electrode gas seal and negative electrode gas seal described later are used. It is preferable to consider the width of.

  In the separator, the width of the oxygen channel [the length in the lateral direction in FIGS. 4B and 4C] is preferably 0.5 mm or more from the viewpoint of improving the air flow. From the viewpoint of suppressing the strength reduction of the separator, the thickness is preferably 5 mm or less.

  The height of the oxygen channel (height of the groove) is preferably 0.5 mm or more from the viewpoint of improving air circulation, and 5 mm or less from the viewpoint of suppressing an increase in the thickness of the separator. It is preferable that

  The width of the rib between the oxygen flow paths [the length in the horizontal direction in FIGS. 4B and 4C] is preferably 0.5 mm or more from the viewpoint of suppressing the strength reduction of the separator, From the viewpoint of improving the air flow in the oxygen channel, the thickness is preferably 5 mm or less.

  The thickness of the thinnest part of the oxygen channel portion (the length from the bottom of the oxygen channel to the other surface) is 0.2 mm or more from the viewpoint of ensuring the strength of the separator and preventing cracking, distortion, and the like. In view of suppressing an increase in the thickness of the separator, the thickness is preferably 5 mm or less.

  The material of the separator is not particularly limited as long as it has high electron conductivity and corrosion resistance. For example, graphite, a mixture of carbon and resin, stainless steel, stainless steel plated with gold or platinum, titanium Preferred are titanium plated with gold or platinum, stainless steel-copper clad, stainless steel-copper clad plated with gold or platinum, and the like.

  Details of the laminate 20a of the positive electrode catalyst layer, the solid polymer electrolyte membrane, and the negative electrode catalyst layer shown in FIG. 2 are shown in FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view taken along line AA in FIG.

  In the fuel cell, the positive electrode catalyst layer, the solid polymer electrolyte membrane, and the negative electrode catalyst layer that constitute the MEA preferably have the same shape in plan view as shown in FIG. Thus, the thickness of the laminate composed of the positive electrode catalyst layer, the solid polymer electrolyte membrane, and the negative electrode catalyst layer can be made uniform, so that the separator (MEA) via the positive and negative electrode diffusion layers and the positive and negative electrode gas seals can be used. Tightening by the two separators disposed on both sides of the sheet becomes uniform, and gas leakage can be suppressed better. In addition, since it is not necessary to accurately determine the positions of the positive electrode catalyst layer and the negative electrode catalyst layer across the solid polymer electrolyte membrane during the production of the MEA, the production of the MEA and thus the production of the fuel cell becomes easier. The productivity can be increased.

  The positive electrode catalyst layer according to MEA of the fuel cell has a function of reducing oxygen diffused through the positive electrode diffusion layer. The positive electrode catalyst layer contains, for example, a carbon powder carrying a catalyst (catalyst-carrying carbon powder) and a proton conductive material, and further contains a binder such as a resin as necessary. Also good.

  The catalyst contained in the positive electrode catalyst layer is not particularly limited as long as it can reduce oxygen, and examples thereof include platinum fine particles. The catalyst may be fine particles composed of an alloy of platinum and at least one metal element selected from the group consisting of iron, nickel, cobalt, tin, ruthenium and gold.

As the carbon powder as the catalyst carrier, for example, carbon black having a BET specific surface area of 10 to 2000 m ² / g and an average particle diameter of 20 to 100 nm is used. The catalyst can be supported on the carbon powder by, for example, a colloid method.

  As a content ratio of the carbon powder and the catalyst, for example, the catalyst is preferably 5 to 400 parts by mass with respect to 100 parts by mass of the carbon powder. This is because such a content ratio can constitute a positive electrode catalyst layer having sufficient catalytic activity. Further, for example, when the catalyst-supported carbon powder is produced by a method of depositing the catalyst on the carbon powder (for example, a colloid method), the catalyst diameter is as long as the carbon powder and the catalyst have the above-mentioned content ratio. This is because it does not become too large and sufficient catalytic activity is obtained.

  The proton conductive material contained in the positive electrode catalyst layer is not particularly limited. For example, a resin having a sulfonic acid group such as a polyperfluorosulfonic acid resin, a sulfonated polyether sulfonic acid resin, or a sulfonated polyimide resin is used. be able to. Specific examples of the polyperfluorosulfonic acid resin include “Nafion (registered trademark)” manufactured by DuPont, “Flemion (registered trademark)” manufactured by Asahi Glass, and “Aciplex (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd. Or the like.

  The content of the proton conductive material in the positive electrode catalyst layer is preferably 2 to 200 parts by mass with respect to 100 parts by mass of the catalyst-supporting carbon powder. If the proton conductive material is contained in the above-mentioned amount, sufficient proton conductivity is obtained in the positive electrode catalyst layer, and the electric resistance value does not become too large, and a fuel cell with good battery performance can be obtained. It is.

  The binder for the positive electrode catalyst layer is not particularly limited. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), fluoropolymers such as tetrafluoroethylene-ethylene copolymer (E / TFE), polyvinylidene fluoride (PVDF) and polychlorotrifluoroethylene (PCTFE), polyethylene, polypropylene, nylon, polystyrene, polyester, Non-fluorinated resins such as ionomer, butyl rubber, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, and ethylene / acrylic acid copolymer can be used.

  The binder content in the positive electrode catalyst layer is preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the catalyst-supporting carbon powder. This is because if the binder is contained in the above-mentioned amount, sufficient binding properties can be obtained for the positive electrode catalyst layer, and the electric resistance value does not become too large, and a fuel cell with good battery performance can be obtained.

  The thickness of the positive electrode catalyst layer is preferably 1 to 50 μm.

  The negative electrode catalyst layer has a function of oxidizing a fuel such as hydrogen diffused through the negative electrode diffusion layer. The negative electrode catalyst layer contains, for example, a carbon powder carrying a catalyst (catalyst carrying carbon powder) and a proton conductive material, and may further contain a binder such as a resin if necessary. Good.

  The catalyst related to the negative electrode catalyst layer is not particularly limited as long as it can oxidize a fuel such as hydrogen. For example, each of the catalysts exemplified as the catalyst related to the positive electrode catalyst layer can be used. Regarding the carbon powder, proton conductive material, and binder related to the negative electrode catalyst layer, the above-described materials exemplified as the carbon powder, proton conductive material, and binder related to the positive electrode catalyst layer can be used.

  The thickness of the negative electrode catalyst layer is preferably 1 to 50 μm.

  The solid polymer electrolyte membrane is not particularly limited as long as it is made of a material that can transport protons and does not exhibit electronic conductivity. Examples of materials that can constitute the solid polymer electrolyte membrane include polyperfluorosulfonic acid resin, specifically, “Nafion (registered trademark)” manufactured by DuPont, and “Flemion (registered trademark)” manufactured by Asahi Glass. “Aciplex (trade name)” manufactured by Asahi Kasei Corporation. In addition, sulfonated polyether sulfonic acid resin, sulfonated polyimide resin, sulfuric acid-doped polybenzimidazole, and the like can also be used as the material for the solid polymer electrolyte membrane.

  The thickness of the solid polymer electrolyte membrane is preferably 5 to 150 μm.

  Details of the positive electrode diffusion layer and the positive electrode gas seal shown in FIG. 2 are shown in FIG. 6A is a plan view, and FIG. 6B is a cross-sectional view taken along line AA in FIG. As described above, the positive electrode diffusion layer 21 is disposed so as to cover the entire surface of the separator in which the oxygen flow path is formed.

  A positive electrode gas seal 30 for suppressing the outflow of fuel gas is provided outside two sides [two vertical sides in FIG. 6A] parallel to or substantially parallel to the oxygen flow path of the separator in the positive electrode diffusion layer 21. It is preferable that the fuel supply manifold 31 and the fuel discharge manifold 32 are formed on the positive electrode gas seal 30. When the positive electrode gas seal is arranged as described above, since the positive electrode gas seal does not exist at the position corresponding to the opening end of the oxygen flow path of the separator, the expansion and contraction of the solid polymer electrolyte membrane that may be caused by the pressure or moisture caused by the fuel The stress of can be relieved.

  Note that the position of the interface between the positive electrode diffusion layer 21 and the positive electrode gas seal 30 is preferably a position corresponding to the outer side (fuel supply manifold side and fuel discharge manifold side) of the oxygen flow path forming part of the separator. If the interface exists at a position corresponding to the oxygen flow path of the separator or at a position of a rib corresponding to the oxygen flow path and the oxygen flow path adjacent to the oxygen flow path, the gas sealing performance may be deteriorated. There is.

  The width of the positive electrode gas seal [the length of a and b in FIG. 6 (a)] is preferably 0.5 mm or more from the viewpoint of improving the gas sealability, and the electrode area is lost. From the viewpoint of reducing the thickness, it is preferably 5 mm or less.

  The thickness of the positive electrode diffusion layer is preferably 100 to 1000 μm. Moreover, it is preferable that the thickness of a positive electrode gas seal is 50-1000 micrometers.

  Details of the negative electrode diffusion layer and the negative electrode gas seal shown in FIG. 2 are shown in FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view taken along line AA in FIG. In the fuel cell, the separator is disposed so that the negative electrode diffusion layer 25 is in contact with the plane of the separator (the surface opposite to the surface on which the oxygen channel is formed).

  In the fuel cell of the present invention, as shown in FIG. 7, a negative electrode gas seal 40 for suppressing the outflow of fuel gas is disposed outside the outer periphery of the rectangular negative electrode diffusion layer 25 in a plan view. A fuel supply manifold 41 is formed by one side of the four sides constituting the quadrangle [the vertical side on the left side in FIG. 7A] and the negative electrode gas seal 40, and the negative electrode diffusion layer 25 of the first side is formed. The fuel discharge manifold 42 is preferably formed by one side (vertical side on the right side in FIG. 7A) facing the side and the negative electrode gas seal 40.

  As described above, the negative electrode diffusion layer 25 is generally made of a material having pores through which fuel gas can flow, but the negative electrode diffusion layer 25, the negative electrode gas seal 40, the fuel supply manifold 41, and the like. By disposing the fuel discharge manifold 42 as described above, a fuel flow path from the fuel supply manifold 41 to the fuel discharge manifold 42 is formed in the entire negative electrode diffusion layer 25. For example, moisture is contained in the negative electrode. Even if water is accumulated in the negative electrode due to supply of a large amount of fuel or generation of water accompanying power generation, it can be discharged well.

  As shown in FIG. 7A, the negative electrode diffusion layer 25 does not need to be formed with a fuel flow path. In this case, since the entire surface is in contact with the separator, the electrical contact resistance Can be minimized. On the other hand, for example, when the supply pressure of the fuel gas is relatively high, the negative electrode diffusion layer may be damaged. Therefore, a groove shape that linearly connects the fuel supply manifold and the fuel discharge manifold to the surface of the negative electrode diffusion layer. It is also possible to form a plurality of the fuel flow paths, preferably in parallel or substantially in parallel, to suppress damage to the negative electrode diffusion layer.

  The width of the negative electrode gas seal [length of c and d in FIG. 7 (a)] is preferably 0.5 mm or more from the viewpoint of improving the gas sealability, and the electrode area is lost. From the viewpoint of reducing the thickness, it is preferably 5 mm or less.

  The thickness of the negative electrode diffusion layer is preferably 100 to 1000 μm. Moreover, it is preferable that the thickness of a negative electrode gas seal is 50-1000 micrometers.

  The positive electrode diffusion layer and the negative electrode diffusion layer are made of a porous electronic conductive material, and for example, a porous carbon sheet subjected to a water repellent treatment is used. In addition, a carbon powder paste containing fluororesin particles (such as PTFE resin particles) is applied to the positive electrode diffusion layer and the catalyst layer side of the negative electrode diffusion layer for the purpose of further improving water repellency and improving contact with the catalyst layer. May be.

  As materials for the positive electrode gas seal and the negative electrode gas seal, various materials known as seal materials in the field of fuel cells, for example, silicon rubber, ethylene-propylene-diene rubber, PTFE film, polyimide film, and the like can be used.

  In the fuel cell of the present invention, in the MEA constituting the fuel cell, the positive electrode and the negative electrode are connected to each other by, for example, a lead body via a resistor and a switch, etc. It is preferable. In the fuel cell having the MEA having such a configuration, when the power generation by the fuel cell is finished, the positive electrode and the negative electrode related to the MEA are short-circuited by, for example, turning on the above-described fuel, and the fuel such as hydrogen remaining in the fuel cell. Can be consumed. Therefore, deterioration of the fuel cell due to fuel remaining in the fuel cell at the end of power generation by the fuel cell can be suppressed.

  In the MEA according to the fuel cell, when the positive electrode and the negative electrode are configured to be conductive through the resistance as described above, the resistance may be, for example, after the fuel cell according to the fuel cell power generation system is stopped, What is necessary is just to use what has a resistance value that the time required for the voltage between the positive electrode and the negative electrode to become 0.1 V or less within 1 minute, and without using a resistor, the MEA can be used in such a time. As long as the voltage between the positive electrode and the negative electrode can be lowered as described above, the connection may be made by connecting with a lead body or the like only through a switch without using a resistor.

  FIG. 8 schematically shows an example of a fuel cell power generation system using the fuel cell of the present invention. In FIG. 8, reference numeral 100 denotes a fuel cell (the fuel cell of the present invention), and 600 denotes a hydrogen supply source for supplying hydrogen as a fuel to the fuel cell 100. The hydrogen supply source 600 is a hydrogen production apparatus having a hydrogen generation container 603 that contains a hydrogen generating substance 604 and a water container 601 that contains water 602. When water 602 is supplied from the water container 601 to the hydrogen generation container 603 through the pipes 501 and 502 using the pump 201, hydrogen is generated by the reaction between the hydrogen generating substance 604 and the water 602, and this hydrogen is supplied to the pipe 503, the water trap ( Condensed water separator) 801 and pipes 504, 505 and 506 are supplied to the fuel cell 100.

  Reference numeral 101 denotes a blower fan for supplying air to the positive electrode of the fuel cell 100, supplying air to the hydrogen consuming device 900, and cooling the fuel cell 100. Moreover, the arrow in FIG. 8 has shown the direction of the flow of the air sent by the ventilation fan 101 (it is the same also in FIG. 10 and FIG. 11 mentioned later). As shown in FIG. 8, the fuel cell power generation system using the fuel cell of the present invention preferably has a blower fan 101.

  The fuel cell power generation system shown in FIG. 8 has exhaust means for discharging the gas in the fuel cell 100 to the outside of the system, and the exhaust means intermittently discharges the gas in the fuel cell 100 to the outside of the fuel cell 100. And a purge valve 310 for discharging the hydrogen gas and a hydrogen consuming device 900 for consuming hydrogen in the gas discharged from the fuel cell 100.

  8 includes a pipe 507, a pressure sensor 400, a purge valve 310, a pipe 509, a water container 601, a pipe 510, a hydrogen consumption device 900, and a pipe 514.

  In the fuel cell power generation system shown in FIG. 8, as power is generated by the fuel cell 100, gas (residual hydrogen not involved in power generation and impure gas diffused from the positive electrode during power generation) is generated on the negative electrode side of the fuel cell 100. Gas) and produced water accumulate, but when the pressure in the fuel cell 100 (and in the pipe 507) increases to some extent by these, the purge valve 310 can discharge the gas and produced water to the pipe 509 side. As described above, the gas and generated water in the fuel cell 100 can be intermittently discharged out of the fuel cell 100 by the action of the purge valve 310. For example, of the hydrogen supplied from the hydrogen supply source, the amount necessary for power generation is reduced. Even if the excess is reduced, the produced water can be discharged well, and the amount of hydrogen contained in the gas can be reduced.

  The system shown in FIG. 8 includes a pressure sensor 400. While the pressure sensor 400 measures the pressure in the pipe 507, the purge valve 310 is opened in a timely manner to supply gas and generated water from the fuel cell 500 to the pipe. Can be discharged to the 509 side. Thus, in the fuel cell power generation system, it is preferable to control the opening / closing operation of the purge valve 310 based on the pressure information obtained by measuring the pressure on the negative electrode side of the fuel cell 100 with the pressure sensor 400. The purge valve is desirably controlled so as to open and close when the pressure difference between the pressure of the negative electrode in the fuel cell and the external pressure (for example, atmospheric pressure) reaches 5 to 300 kPa. If the differential pressure is opened at less than 5 kPa, the pressure difference is too small and the ability to discharge water decreases. If the differential pressure does not open until the differential pressure exceeds 300 kPa, the internal pressure becomes too high and the MEA may be damaged. .

  With such a configuration, it is possible to appropriately generate power while measuring pressure information in the fuel cell, so that the pressure becomes too high and hydrogen leaks from the fuel cell or the fuel cell bursts. Can be suppressed. In addition, it is possible to generate power so that the output can be properly maintained in consideration of the output state of the fuel cell and the pressure information.

  In the system shown in FIG. 8, the gas and generated water discharged from the fuel cell 100 are introduced from the pipe 509 to the water container 601 of the hydrogen supply source 600. Since the water container 601 also functions as a water trap, the generated water discharged from the fuel cell 100 is collected in the water container 601. As described above, in the fuel cell power generation system, in order to recover water (produced water) contained in the gas discharged from the fuel cell, water recovery means such as a water trap is provided between the purge valve and the hydrogen consuming device. It is preferable to provide. By adopting such a configuration, it is possible to supply the gas to the hydrogen consuming device after removing the generated water from the gas discharged from the fuel cell. Therefore, the hydrogen consumption efficiency due to accumulation of the generated water in the hydrogen consuming device. Can be suppressed, and more efficient hydrogen removal can be achieved.

  Further, in the fuel cell power generation system, it is preferable to use the generated water in the fuel cell recovered by the water recovery means for the reaction with the hydrogen generating substance (that is, the production of hydrogen). In the system of FIG. 8, since the water container 601 of the hydrogen supply source 600 also serves as the water recovery means, the generated water discharged from the fuel cell 100 can be used as water for hydrogen production. With such a configuration, the system can be made compact and the energy utilization rate can be increased.

  In the system shown in FIG. 8, the gas from which water (product water) has been removed by the water container 601 (the gas discharged from the fuel cell 100) is introduced into the hydrogen consuming apparatus 900 through the pipe 510. The hydrogen consuming apparatus 900 of FIG. 8 has an MEA (not shown), and consumes hydrogen in the gas by the same mechanism as the power generation by the MEA of the fuel cell 100. A pipe 514 connected to the hydrogen consuming apparatus 900 is in contact with outside air, and the gas from which hydrogen has been removed by the hydrogen consuming apparatus 900 is discharged out of the system through the pipe 514. In the system shown in FIG. 8, the outlet of the pipe 514 is arranged so as to be blown from the blower fan 101, so that even if hydrogen remains slightly without being processed by the hydrogen consuming device, dilution is performed. However, it can be discharged out of the system.

  In a fuel cell, in general, when power generation is stopped, deterioration occurs when the state in which air is stored in the positive electrode and hydrogen is stored in the negative electrode in the fuel cell continues for a long time. The cause of this is not clear, but in this case, since the voltage is maintained in a higher state than during power generation, it is presumed that the positive and negative carbon and catalyst are oxidized. Therefore, the fuel cell power generation system may be configured to prevent hydrogen from entering the fuel cell at the end of power generation or may be configured to remove hydrogen remaining in the fuel cell. preferable.

  In the system shown in FIG. 8, a three-way valve 302 is provided between a pipe 504 and a pipe 505 for introducing hydrogen from the hydrogen supply source 600 into the fuel cell. Furthermore, this pipe 511 is connected to a pipe 510 installed between the water container 601 and the hydrogen consuming apparatus 900. Therefore, at the end of power generation of the fuel cell 100, the three-way valve 302 is operated to supply the hydrogen from the hydrogen supply source 600 directly to the hydrogen consuming device 900 through the pipes 511 and 510 without being sent to the fuel cell 100. Can be processed. Accordingly, in the system shown in FIG. 8, at the end of power generation by the fuel cell 100, hydrogen can be prevented from entering the fuel cell 100 and deterioration of the fuel cell 100 due to the hydrogen can be suppressed.

  Further, in the system shown in FIG. 8, a three-way valve 301 is connected to pipes 501 and 502 that connect a water container 601 and a hydrogen generation container 603 of the hydrogen supply source 600, and the three-way valve 301 is connected to a pipe 512. Are also connected. Further, the pipe 512 is connected to a pipe 505 and a pipe 506 for supplying hydrogen from the hydrogen supply source 600 to the fuel cell via the three-way valve 303. Therefore, at the end of power generation of the fuel cell 100, the three-way valves 301 and 303 are operated, and the purge valve 310 is further operated, so that the water in the water container 601 can be supplied into the fuel cell 100 through the pipe 512 and the pipe 506. Thus, in the system shown in FIG. 8, at the end of power generation by the fuel cell 100, the hydrogen remaining in the fuel cell 100 can be replaced with water, so that the hydrogen remains in the fuel cell 100. Therefore, the deterioration of the fuel cell 100 can also be suppressed.

  Further, as described above, since water can be stored in the fuel cell 100 at the end of power generation by the fuel cell 100, the solid polymer electrolyte membrane in the MEA of the fuel cell 100 is kept in a wet state. Is possible. Generally, in a polymer electrolyte fuel cell, if it is stopped for a long time, the polymer electrolyte membrane is dried, but in such a state, self-wetting by power generation is required at the time of restart, and the output is reduced. It takes time to get up. However, in the system shown in FIG. 8, as described above, when the power generation by the fuel cell 100 is completed, the fuel cell 100 can be filled with water. Therefore, it becomes possible to demonstrate a high output.

  Furthermore, in the system shown in FIG. 8, since water supplied into the fuel cell 100 at the end of power generation can be supplied from the water container 601 of the hydrogen supply source 600, there is no need to provide a separate water container or the like, can do. Further, the water supplied into the fuel cell at the end of power generation may be supplied directly from the water recovery means (water trap).

  In the fuel cell power generation system using the fuel cell of the present invention, as a hydrogen supply source for supplying hydrogen to the fuel cell, as shown in FIG. 8, hydrogen generated by the reaction between the hydrogen generating substance and water is supplied. It is preferable that the hydrogen production apparatus have a mechanism for

  The hydrogen production apparatus (hydrogen supply source) 600 according to the system shown in FIG. 8 includes the hydrogen generation container 603 and the water container 601 as described above. The hydrogen generating container 603 contains a hydrogen generating substance 604. Water 602 is supplied from the water container 601 to the hydrogen generating container 603, and the hydrogen generating substance 604 and the water 602 are reacted in the hydrogen generating container 603 to produce hydrogen. Hydrogen generated in the hydrogen generation container 603 is supplied to the fuel cell 100 through a fuel flow path including pipes 503, 504, 505, and 506.

  A water supply pump 201 is provided in the pipes 501 and 502 for supplying water from the water container 601 to the hydrogen generation container 603. The water contained in the water container 601 may be a liquid containing at least water, such as neutral water, an acidic aqueous solution, or an alkaline aqueous solution, and suitable water depending on the reactivity with the hydrogen generating material used. Just choose.

  The hydrogen generation container 603 and the water container 602 may be detachable. As a result, when the hydrogen generating material in the hydrogen generating container 603 is completely consumed or when the water in the water container 602 is exhausted, these are removed and the hydrogen generating container 603 filled with the hydrogen generating material or water is filled. By newly attaching the water container 602, hydrogen production can be performed again.

  The hydrogen generating material accommodated in the hydrogen generating vessel 603 is not particularly limited, but is preferably a substance capable of generating hydrogen by reacting with water at a low temperature of 120 ° C. or lower. For example, a metal such as aluminum, silicon, zinc, magnesium; one or more elements selected from aluminum, silicon, zinc, and magnesium are contained in an amount of 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more. Alloys, metal hydrides, and the like can be preferably used.

  The hydrogen generating material made of the metal or alloy is stabilized by forming an oxide film on the surface. For this reason, in order to increase the reactivity, it is preferable to make the particle size of the hydrogen generating material as small as possible and increase the reaction area. For example, the average particle diameter of the hydrogen generating substance particles is preferably 100 μm or less, and more preferably 50 μm or less. The particle shape is preferably flakes in order to increase reaction efficiency. If the particle size is too small, the bulk density is reduced, the packing density is lowered, and handling becomes difficult. Therefore, the particle size of the hydrogen generating material is preferably 0.1 μm or more.

  As a method for measuring the average particle diameter, for example, a laser diffraction / scattering method or the like can be used. Specifically, this is a particle diameter distribution measurement method using a scattering intensity distribution detected by irradiating a measurement target substance dispersed in a liquid phase such as water with laser light. As a particle size distribution measuring apparatus using a laser diffraction / scattering method, for example, “Microtrack HRA” manufactured by Nikkiso Co., Ltd. can be used.

  Examples of the metal hydride that can be used as the hydrogen generating substance include sodium borohydride and potassium borohydride. These metal hydrides are relatively stable in an aqueous alkali solution, but when a catalyst is present, they can rapidly react with water to generate hydrogen. As the catalyst, for example, metals such as Pt and Ni, acids, and the like can be used.

  As the hydrogen generating substance, those exemplified above may be used alone or in combination of two or more.

  In order to increase the reactivity with water, the hydrogen generating substance may be heated while being mixed with water, or heated water may be supplied.

  Further, by using the hydrogen generating material together with a heat generating material (a material other than the hydrogen generating material) that generates heat by reacting with water, even if low temperature (for example, about 5 ° C.) water is supplied, Heat generation increases the temperature in the reaction system, enabling rapid hydrogen generation.

  The exothermic substance that generates heat by reacting with water, for example, calcium oxide, magnesium oxide, calcium chloride, magnesium chloride, calcium sulfate, etc., becomes a hydroxide upon reaction with water, or generates heat when hydrated. Examples include alkali metal or alkaline earth metal oxides, chlorides, sulfate compounds, and the like. In addition, those that generate hydrogen by reaction with water, such as metal hydrides such as sodium borohydride, potassium borohydride, and lithium hydride, can be used as a hydrogen generating substance as described above. However, it can also be used as a heat generating material when the metal or alloy is used as a hydrogen generating material.

  In particular, when a metal such as aluminum, silicon, zinc, or magnesium or an alloy mainly composed of one or more elements selected from aluminum, silicon, zinc, and magnesium is used as the hydrogen generating material, the exothermic material is used. It is preferable to use together. On the other hand, when the metal hydride is used as a hydrogen generating substance, hydrogen can be produced at a relatively good rate without using the exothermic substance. May be increased.

  The material and shape of the hydrogen generation container 603 are not particularly limited as long as it can store a hydrogen generating substance that generates hydrogen, but the material and shape from which water and hydrogen do not leak from other than the water supply port and the hydrogen outlet port. Is preferred. As a specific material of the container, a material that does not easily transmit water and hydrogen and that does not break even when heated to about 120 ° C. is preferable. For example, a metal such as aluminum or iron, or a resin such as polyethylene or polypropylene may be used. Can be used. Further, as the shape of the container, a prismatic shape, a cylindrical shape or the like can be adopted.

  There is no restriction | limiting in particular about the water container 601, For example, the tank etc. which accommodate the water similar to what is used for the conventional hydrogen production apparatus are employable.

  When water in the water container 601 is supplied to the hydrogen generation container 603 through the pipes 501 and 502, it reacts with the hydrogen generating substance in the hydrogen generation container 603 to generate hydrogen, but is present in the hydrogen generation container 603. In some cases, unreacted water is mixed into the generated hydrogen, and the mixture of these flows into the fuel cell 100 through the fuel flow path including the pipe 503 and the like.

  Therefore, the hydrogen production apparatus (hydrogen supply source) 600 is preferably provided with a condensed water separator (water trap) 801 in the middle of the fuel flow path for supplying hydrogen to the fuel cell. As shown in FIG. 8, the hydrogen gas discharged from the hydrogen generation vessel 603 is introduced into the condensed water separator 801 through the pipe 503. During this time, the water contained in the hydrogen gas is cooled in the pipe 503 and becomes condensed water. Since condensed water falls to the lower part of the condensed water separator 801 by gravity, hydrogen gas can be separated from water. The separated hydrogen gas is supplied to the fuel cell 100 through the pipe 504 and the like.

  Further, as shown in FIG. 8, if the condensed water separator 801 and the water container 601 are connected by a water recovery pipe 513, the water separated by the condensed water separator 801 can be recovered in the water container 601. By recovering the separated water, the water supplied for hydrogen generation can be used efficiently, and the water container 601 can be made more compact. In addition, as shown in FIG. 8, the pump 202 for sending out water may be installed in the water collection | recovery piping 513 which connects the condensed water separator 801 and the water container 601. As shown in FIG.

  The hydrogen consuming apparatus according to the fuel cell power generation system is not particularly limited as long as it can consume and remove hydrogen in the system. For example, the hydrogen consuming apparatus has an MEA and has the same mechanism as the power generation by the MEA according to the fuel cell. And a device having a catalyst capable of oxidizing hydrogen.

  As an apparatus for consuming hydrogen by the same mechanism as the power generation by the MEA related to the fuel cell, specifically, like the MEA constituting the fuel cell shown in FIGS. 2 and 3, a positive electrode diffusion layer, a positive electrode catalyst layer, Hydrogen consumption having MEA having a structure in which a solid polymer electrolyte membrane, a negative electrode catalyst layer, and a negative electrode diffusion layer are sequentially laminated, and the positive electrode and the negative electrode are connected so as to be able to conduct through, for example, a switch and a resistor Apparatus.

  Regarding the positive electrode diffusion layer, the positive electrode catalyst layer, the solid polymer electrolyte membrane, the negative electrode catalyst layer, and the negative electrode diffusion layer according to the MEA of the hydrogen consuming apparatus, the positive electrode diffusion layer, the positive electrode catalyst layer, and the solid polymer electrolyte membrane according to the MEA of the fuel cell As the negative electrode catalyst layer and the negative electrode diffusion layer, the same ones as described above can be used.

  In the case of the hydrogen consuming apparatus described above, when it is necessary to consume hydrogen in the gas, a switch is made at the connection between the positive electrode and the negative electrode, and conduction between the positive electrode and the negative electrode of the MEA is performed. Can be consumed. This completely eliminates hydrogen in the gas that is exhausted from the fuel cell and needs to be discharged outside the system, and hydrogen that enters the fuel cell from the hydrogen supply source at the end of power generation by the fuel cell, Alternatively, the amount of hydrogen can be greatly reduced.

  In the hydrogen consuming apparatus having the MEA, when the positive electrode and the negative electrode of the MEA are connected via a resistor, the resistance may be, for example, after the hydrogen is introduced into the hydrogen consuming device and then the positive electrode of the MEA A resistor having such a resistance value that the time required for the voltage between the negative electrodes to be 0.1 V or less is within one minute may be used. Further, if the voltage between the positive electrode and the negative electrode of the MEA can be reduced as described above without using a resistor, the positive electrode and the negative electrode of the MEA are only switches without using a resistor. It is good also as a conduction | electrical_connection by connecting with a lead body etc. via this.

  As described above, since the hydrogen consuming apparatus includes the MEA similarly to the fuel cell, for example, a fuel cell having a plurality of MEAs (stack) is used, and a part of the MEA (for example, 1) is used. 1, 2, 3, etc.) can be used as the hydrogen consuming device, and the fuel cell and the hydrogen consuming device can be integrated.

  The fuel cell power generation system shown in FIG. 8 includes an integrated product of the fuel cell 100 and the hydrogen consuming apparatus 900. FIG. 9 is a perspective view schematically showing an example of the integrated product. In the integrated product shown in FIG. 9, among the plurality of MEAs 20 stacked via the separator 10, the upper part constitutes the fuel cell 100 and the lower part constitutes the hydrogen consuming apparatus 900. A fuel supply port 80 is connected to, for example, a pipe 510 in FIG. Reference numeral 90 denotes a fuel discharge port, which is connected to, for example, a pipe 514 in FIG.

  By configuring the fuel cell power generation system using an integrated body of the fuel cell and the hydrogen consuming device, the system can be more easily downsized. In this case, the MEA used as a hydrogen consuming device is not connected to the MEA used for power generation, and the gas from which hydrogen has been removed by the hydrogen consuming device can be efficiently exhausted out of the system, and power can be generated efficiently. The MEA used as the hydrogen consuming device and the MEA used for power generation are configured so that the internal gas cannot pass back and forth.

  FIG. 10 shows a schematic diagram of another example of the fuel cell power generation system using the fuel cell of the present invention. In the fuel cell power generation system shown in FIG. 10, a pipe 505 for supplying hydrogen from the hydrogen supply source 600 to the fuel cell 100 and a three-way valve 303 connected to the pipe 506 are further provided with a pipe 515 for taking outside air. It is connected. At the end of power generation by the fuel cell 100, the three-way valve 303 is operated so that air can be taken into the fuel supply port of the fuel cell 100 through the pipe 515. Further, although not shown, the MEA in the fuel cell 100 is configured so that the positive electrode and the negative electrode can conduct as described above, and while taking air into the fuel cell 100, the positive electrode and the negative electrode The hydrogen remaining in the fuel cell 100 can be consumed.

  In the fuel cell power generation system shown in FIG. 10, there is an action by taking air into the fuel supply port of the fuel cell 100 and an action by short-circuiting the positive electrode and the negative electrode of the MEA of the fuel cell 100. At the end of power generation by the fuel cell, deterioration of the fuel cell due to hydrogen remaining in the fuel cell can be suppressed.

  FIG. 11 shows a schematic diagram of another example of a fuel cell power generation system using the fuel cell of the present invention. The fuel cell power generation system shown in FIG. 11 is an example provided with a hydrogen consuming apparatus 900 having a catalyst capable of oxidizing hydrogen. The hydrogen consuming apparatus 900 is disposed at a position where the air sent from the blower fan 101 can be taken in, and is configured to efficiently consume hydrogen in a small space. Therefore, downsizing of the fuel cell power generation system having the configuration shown in FIG. 11 is easy.

  Examples of the hydrogen consuming apparatus having a catalyst that can oxidize hydrogen include a filter containing the catalyst, a cylinder-shaped exterior body filled with the catalyst, and the like. In addition, as a catalyst which can oxidize hydrogen, the various catalysts previously illustrated as a catalyst in the negative electrode catalyst layer of MEA can be used, for example.

  In the above, the fuel cell of the present invention and the fuel cell power generation system using the fuel cell of the present invention have been described with reference to FIGS. 1 to 11. However, FIGS. The fuel cell power generation system using the fuel cell of the invention and only some of the components usable in the system are shown, and the fuel cell of the present invention and the fuel cell power generation using the fuel cell of the present invention The system is not limited to those shown in these drawings or having the components shown in these drawings.

  As described above, with the fuel cell of the present invention, it is easy to reduce the size of the fuel cell itself and the fuel cell power generation system. Therefore, the fuel cell of the present invention can be preferably used in various applications in which conventional fuel cells are used, including power supply applications of highly functional portable electronic devices such as cordless devices such as personal computers and mobile phones.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Example 1
A fuel cell having the structure shown in FIG. 1 was produced. As the laminate of the positive electrode catalyst layer, the solid polymer electrolyte membrane, and the negative electrode catalyst layer, one having the configuration shown in FIG. 5 was used. As the solid polymer electrolyte membrane 23, “Nafion (registered trademark) 112” manufactured by DuPont was used. Pt-supported carbon (“TEC10E50E” manufactured by Tanaka Kikinzoku Co., Ltd.) and a 5 mass% Nafion solution (manufactured by Aldrich) were mixed in a predetermined amount, and this was applied to one side of a polytetrafluoroethylene sheet and dried. . Hot-press the polytetrafluoroethylene sheet on both sides of the solid polymer electrolyte membrane so that the application surface of the mixture of Pt-supported carbon and Nafion solution is on the solid polymer electrolyte membrane side, A laminate of a positive electrode male catalyst, a solid polymer electrolyte membrane, and a negative electrode catalyst layer was obtained. Thereafter, the laminate was cut out so that the outer shape was 24 mm × 85.5 mm.

  “GDL10DC” (thickness: 470 μm) manufactured by SGL Carbon was cut into a size of 24 mm × 71.5 mm and used for the positive electrode diffusion layer. Further, two 24 mm × 7 mm silicon rubber sheets (thickness: 0.3 mm) were prepared for the positive electrode gas seal, and 20 mm × 3 mm holes (fuel supply manifold and fuel discharge manifold) were formed in both.

  For the negative electrode gas seal, the same silicon rubber sheet as the positive electrode gas seal is used, the size is set to 24 mm × 85.5 mm, and a negative electrode diffusion layer is inserted and a fuel supply manifold and a fuel discharge manifold are formed. A hole with a size of 81.5 mm was formed. For the negative electrode diffusion layer, the same material as that used for the positive electrode diffusion layer was used, and cut into a size of 20 mm × 75.5 mm.

  Twelve MEAs were produced by laminating the above laminate, positive electrode diffusion layer, positive electrode gas seal, negative electrode diffusion layer and negative electrode gas seal in the order and arrangement shown in FIG.

  A separator made of carbon (the thickness of the thickest part is 2 mm) and having the configuration shown in FIG. 4 was used. The outer shape was 24 mm × 85.5 mm, and the sizes of the fuel supply manifold 11 and the fuel discharge manifold 12 were 20 mm × 3 mm. The oxygen flow path (oxygen flow path that also serves as a cooling medium flow path) 13 had a width of 1.5 mm and a depth of 1.5 mm, and the rib 14 between the oxygen flow paths had a width of 1 mm.

The twelve MEAs are stacked while the separator is interposed between the MEAs so that the oxygen flow path forming surface side is on the positive electrode diffusion layer side, and two end plates (made of aluminum and having a size) 38 mm × 90 mm) and fixed with bolts and nuts to produce a fuel cell having the structure shown in FIG. The volume of this fuel cell was 143 cm ³ .

Comparative Example 1
A fuel cell was produced in the same manner as in Example 1 except that the separator was changed to the one shown in FIG. 12A is a plan view of the surface side where the oxygen flow path 13 is not formed, FIG. 12B is a cross-sectional view taken along line AA in FIG. 12A, and FIG. 12C is a view where the oxygen flow path 13 is formed. FIG.

The separator used in the fuel cell of Comparative Example 1 had an outer shape of 24 mm × 85.5 mm, the thickness of the thickest part was 3 mm, and the sizes of the fuel supply manifold 11 and the fuel discharge manifold 12 were 20 mm × 3 mm. The oxygen channel 13 was 1.5 mm wide and 1.5 mm deep, and the rib 14 between the oxygen channels was 1 mm wide. Further, on the surface opposite to the formation surface of the oxygen flow path 13, a fuel flow path 15 from the fuel supply manifold 11 to the fuel discharge manifold with a width of 1 mm and a depth of 1 mm [dots are inserted in FIG. Display] was formed. The volume of the fuel cell of Comparative Example 1 was 184 cm ³ .

It is a perspective view showing the outline of an example of the fuel cell of this invention. It is an exploded view of the principal part of the fuel cell of FIG. It is sectional drawing of the principal part of the fuel cell of FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of an example of the separator concerning the fuel cell of this invention, (a) is a top view of the side arrange | positioned at a negative electrode diffused layer, (b) is the sectional view on the AA line of (a), (c) is It is a top view of the side arrange | positioned at a positive electrode diffusion layer. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of an example of the laminated body of the positive electrode catalyst layer, the solid polymer electrolyte membrane, and the negative electrode catalyst layer in the electrode-electrolyte integrated object which concerns on the fuel cell of this invention, (a) is a top view, (b) is (a). It is an AA sectional view taken on the line. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of an example of the positive electrode diffusion layer in the electrode-electrolyte integrated object which concerns on the fuel cell of this invention, (a) is a top view, (b) is the sectional view on the AA line of (a). BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of an example of the negative electrode diffused layer in the electrode-electrolyte integrated object which concerns on the fuel cell of this invention, (a) is a top view, (b) is the sectional view on the AA line of (a). It is a schematic diagram which shows an example of the fuel cell power generation system using the fuel cell of this invention. It is a perspective view which shows the outline of an example of the integrated object of the fuel cell of this invention, and a hydrogen consumption apparatus. It is a schematic diagram which shows the other example of the fuel cell power generation system using the fuel cell of this invention. It is a schematic diagram which shows the other example of the fuel cell power generation system using the fuel cell of this invention. It is the schematic of the separator used for the fuel cell of the comparative example 1, (a) is a top view by the side arrange | positioned at a negative electrode diffused layer, (b) is the sectional view on the AA line of (a), (c) is It is a top view of the side arrange | positioned at a positive electrode diffusion layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Separator 11 Fuel supply manifold 12 Fuel discharge manifold 13 Oxygen flow path 100 Fuel cell

Claims (8)

A positive electrode having a positive electrode catalyst layer that reduces oxygen; a negative electrode having a negative electrode catalyst layer that oxidizes fuel; and a solid polymer electrolyte membrane disposed between the positive electrode and the negative electrode. A fuel cell formed by laminating a plurality of rectangular electrode / electrolyte integrated bodies via a separator,
The separator disposed between two adjacent electrode / electrolyte integrals has a quadrangular shape in plan view and is composed of one sheet,
The positive electrode, the negative electrode, the solid polymer electrolyte membrane, and the separator have a fuel supply manifold in the vicinity of one of the four sides forming a quadrangle, and a fuel discharge in the vicinity of the other side opposite to the one side. A manifold is formed,
On one surface of the separator, a plurality of oxygen flow paths that linearly connect two sides other than the two opposite sides on which the fuel supply manifold and the fuel discharge manifold are formed are formed in parallel or substantially parallel to each other. And the other surface of the separator is planar,
The separator has a surface having an oxygen channel in contact with the positive electrode of the electrode / electrolyte integrated product, and the other planar surface is adjacent to the electrode / electrolyte integrated product through the separator and the negative electrode of the electrode / electrolyte integrated product. A fuel cell characterized by being in contact with   The fuel cell according to claim 1, wherein the negative electrode of the electrode / electrolyte integrated product has a negative electrode diffusion layer, and the negative electrode diffusion layer is in contact with the separator.   The fuel cell according to claim 2, wherein a fuel flow path for connecting the fuel supply manifold and the fuel discharge manifold is formed on a surface of the negative electrode diffusion layer in contact with the separator.   The negative electrode diffusion layer is rectangular in plan view, and a negative electrode gas seal for suppressing outflow of fuel gas is disposed outside the outer periphery of the negative electrode diffusion layer. 3. A fuel supply manifold is formed by one of the sides and the negative electrode gas seal, and a fuel discharge manifold is formed by one side of the negative electrode diffusion layer facing the one side and the negative gas seal. Or 3. The fuel cell according to 3.   The fuel according to any one of claims 1 to 4, wherein the positive electrode of the electrode / electrolyte integrated product has a positive electrode diffusion layer, and the positive electrode diffusion layer is disposed at a location covering the entire oxygen flow path of the separator. battery.   The positive electrode diffusion layer is quadrangular in plan view, and a positive electrode gas seal for suppressing the outflow of fuel gas is disposed outside two sides of the positive electrode diffusion layer that are parallel or substantially parallel to the oxygen flow path of the separator. The fuel cell according to claim 5, wherein a fuel supply manifold and a fuel discharge manifold are formed on the positive electrode gas seal.   The fuel cell according to any one of claims 1 to 6, wherein an oxygen flow path of the separator also serves as a cooling medium flow path.   The fuel cell according to any one of claims 1 to 7, wherein the positive electrode catalyst layer, the negative electrode catalyst layer, and the solid polymer electrolyte of the electrode / electrolyte integrated product have the same shape in plan view.

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