JP2006140061A - Electrode and membrane-electrode assembly of fuel cell, and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system low in a running cost, hardly generating deterioration of output. <P>SOLUTION: A membrane-electrode assembly (MEA) includes an electrolytic membrane 11, a cathode pole 13 jointed to one surface of the membrane 11 to which, air is supplied, and an anode pole jointed to the other surface of the membrane 11 to which, hydrogen is supplied. At least either the cathode pole 13 or the anode pole 12 has a base material having gas permeability and catalyst layers 13a, 12a formed on a surface of the base material on the side of the membrane 11. The layers 13a, 12a includes an infinite number of catalyst-carrying carbons 81 carrying catalyst metals 81b on carbon powder 81a and high-polymer electrolytes 82 jointing to the base material as well as jointing each carbon 81 while contacting with one another. Hydrophilic layers 72 are formed between the electrolytes 82 and each carbon 81 to communicate the hydrophilic layers 72 with one another. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrode constituting a cathode electrode or an anode electrode of a fuel cell, a membrane electrode assembly, and a fuel cell system.

  Conventionally, a fuel cell system using a membrane electrode assembly (MEA) 90 as shown in FIG. 19 is known. The membrane electrode assembly 90 includes an electrolyte membrane 91 made of a solid polymer membrane such as Nafion (registered trademark, Nafion (manufactured by Dupon)), and a cathode electrode joined to one surface of the electrolyte membrane 91 and supplied with air. 93 and an anode 92 that is joined to the other surface of the electrolyte membrane 91 and is supplied with a fuel such as hydrogen.

  The cathode electrode 93 includes a gas-permeable base material such as carbon cloth, carbon paper, carbon felt, and the like, and a cathode catalyst layer 93a formed on one surface of the base material. A portion of the cathode electrode 93 other than the cathode catalyst layer 93a is formed of a base material, which is a cathode diffusion layer 93b that diffuses air to the cathode catalyst layer 93a on the non-electrolyte side.

  The anode 92 also includes the base material and an anode catalyst layer 92a formed on one surface of the base material. The portion other than the anode catalyst layer 92a in the anode electrode 92 is also formed of a base material, and this is an anode diffusion layer 92b that diffuses air to the anode catalyst layer 92a on the non-electrolyte side.

  As shown in FIG. 20, the cathode catalyst layer 93a and the anode catalyst layer 92a are composed of an infinite number of catalyst-supporting carbons 81 formed by supporting a catalyst metal 81b such as platinum (Pt) on a substantially spherical carbon powder 81a, and each catalyst support. It includes a polymer electrolyte 82 that bonds carbon 81 to each other and bonds to a base material (not shown). As the polymer electrolyte 82, the same one as the electrolyte membrane 91 can be used.

  The membrane electrode assembly 90 is sandwiched between separators (not shown) to form a fuel cell as a minimum power generation unit, and a large number of these cells are stacked to form a fuel cell stack. Air is supplied to the cathode catalyst layer 93a by air supply means, and hydrogen or the like is supplied to the anode catalyst layer 92a by hydrogen supply means or the like. Thus, the fuel cell system is configured.

In the membrane electrode assembly 90, hydrogen ions (H ⁺ ; protons) and electrons are generated from the fuel by an electrochemical reaction in the anode catalyst layer 92a. Protons move in the electrolyte membrane 91 toward the cathode catalyst layer 93a in the form of H ₃ O ⁺ accompanied by water molecules. The electrons flow through the load connected to the fuel cell system and flow into the cathode catalyst layer 93a. On the other hand, in the cathode catalyst layer 93a, water is generated from oxygen, protons and electrons contained in the air. The fuel cell system can continuously generate an electromotive force by continuously performing such an electrochemical reaction.

  However, since protons generated in the anode catalyst layer 92a of the membrane electrode assembly 90 move in the electrolyte membrane 91 toward the cathode catalyst layer 93a with water molecules, the anode catalyst layer 92a and the electrolyte membrane 91 On the anode catalyst layer 92a side, the moisture content decreases and the anode catalyst layer 92a tends to dry, proton transfer is hindered, and the output of the fuel cell system tends to decrease.

  Further, in the cathode catalyst layer 93a, water is transferred by protons and produced water generated by the cell reaction, so that water becomes excessive and air diffusion is inhibited (hereinafter referred to as “flooding”). Battery system output tends to decrease.

  Therefore, conventionally, the problem of drying of the anode catalyst layer 92a and the electrolyte membrane 91 is solved by humidifying hydrogen gas with a humidifier, and the problem of the cathode catalyst layer 93a is made water repellent. We are trying to solve this problem by making it easy to discharge water to the outside. Conventionally, Patent Documents 1 to 6 disclose techniques related to the present invention.

Japanese Patent Laid-Open No. 2004-199915 JP 2004-185900 A JP 2003-59505 A JP 2002-324557 A JP 2003-7308 A JP 2002-134120 A

  However, if the humidifier is provided on the anode electrode 92 side as described above, energy is consumed for its operation, and the running cost of the fuel cell system becomes high. In this case, more excess water exists on the cathode electrode 93 side, and there is a concern that the output is reduced due to flooding.

  The present invention has been made in view of the above-described conventional situation, and an object to be solved is to provide a fuel cell system that has a low running cost and is unlikely to cause a decrease in output.

  According to the inventor's knowledge, in a fuel cell, an electrolyte membrane such as a solid polymer membrane moves water well, but the anode and cathode electrodes joined to the electrolyte membrane move water well. I can't. As described above, since the anode electrode and the cathode electrode contain innumerable catalyst-supporting carbon and polymer electrolyte, the cause thereof is that they do not contain water locally, The inventors have inferred that contact between the catalyst-carrying carbons is hindered or that a hydrophilic layer continuous with each other is not formed by water between the polymer electrolyte and each catalyst-carrying carbon.

  That is, as shown in FIG. 20, in the conventional MEA 90, the electrolyte membrane 91 includes water 32 at least during use, and a hydrophilic layer 71 continuous in the thickness direction is formed in the electrolyte membrane 91. Is inferred. However, although the anode catalyst layer 92a and the cathode catalyst layer 93a contain water 32 at least during use, the contact between the catalyst-supporting carbons 81 is obstructed, or the polymer electrolyte 82 and the catalyst-supporting carbon 81 It is inferred that the hydrophilic layers 72 that are continuous with each other are not formed by the water 32 therebetween. For this reason, protons generated in the anode catalyst layer 92a are difficult to move in the anode catalyst layer 92a due to high ion resistance in the anode catalyst layer 92a, and ion resistance from the anode catalyst layer 92a into the electrolyte membrane 91 is also high. For this reason, it is difficult to move in the electrolyte membrane 91 and it is difficult to move in the cathode catalyst layer 93a because the ion resistance in the cathode catalyst layer 93a is high. In addition, the generated water generated in the cathode catalyst layer 93a accumulates on the cathode electrode 93 side, and it is easy for flooding to occur, and the anode electrode 92 and the electrolyte membrane 91 cause insufficient water to impede further proton conductivity. it is conceivable that.

  In addition, the inventor also inferred that the polymer electrolyte 82 has polarity and the anode electrode 92 and the cathode electrode 93, which cannot move water well, are not properly oriented.

  The inventor made a prototype of a fuel cell system that solved the problems caused by these inferences, and found that high output could be obtained even with light or no humidification. The present invention has thus been completed.

The electrode of the fuel cell of the present invention has a gas-permeable base material and a catalyst layer formed on one surface of the base material, and the catalyst layer is made by supporting a catalytic metal on carbon powder. A fuel cell electrode comprising: a catalyst-supporting carbon; and a polymer electrolyte that binds each of the catalyst-supporting carbons to each other and to the base material,
The catalyst layer includes the polymer electrolyte and the catalyst-supporting carbons that are in contact with each other. A hydrophilic layer is formed between the polymer electrolyte and the catalyst-supporting carbon, and the hydrophilic layers communicate with each other. It is characterized by being.

  In the electrode of the present invention, since the hydrophilic layer is continuously formed in the catalyst layer, protons easily move along this. In addition, since the polymer electrolyte orients the ion exchange groups of the polymer electrolyte on the hydrophilic layer side, the hydrophilic layer is effectively used for proton transfer. Therefore, in the fuel cell system, the ion-reactive group of the polymer electrolyte is on the catalyst-carrying carbon side between the catalyst-carrying carbon and the polymer electrolyte in the catalyst layer of the anode electrode, the electrolyte membrane, and the cathode electrode. Oriented to form a water channel, and the water channel is formed on the entire surface of the catalyst-carrying carbon, so the amount of water necessary for proton transfer is retained in the water channel and moves well in the water channel, and excess water is required Therefore, a high output can be obtained with light or no humidification.

  Therefore, according to the present invention, it is possible to realize a fuel cell system that is low in running cost and hardly causes a decrease in output.

  In addition, the said patent documents 1-6 have description about the hydrophilization of catalyst carrying | support carbon. However, the fuel cell systems disclosed therein cannot achieve the same effects as the fuel cell system obtained by the electrode of the present invention. The anode electrode and cathode electrode disclosed therein do not contain water locally, in which contact between the catalyst-supporting carbons is hindered, or between the polymer electrolyte and each catalyst-supporting carbon. The present inventors infer that the hydrophilic layers that are continuous with each other are not formed by water. Moreover, in these, although the polymer electrolyte is partially oriented, the inventors infer that they are not formed continuously. Furthermore, the electrode of the present invention does not require expensive plasma irradiation to make each catalyst-supporting carbon hydrophilic, which contributes to lowering the fuel cell system.

  The electrode of the present invention can be manufactured by applying an electrode paste to one surface of a substrate. For the application, means such as printing can be employed.

The membrane electrode assembly of the fuel cell according to the present invention includes an electrolyte membrane, a cathode electrode joined to one surface of the electrolyte membrane and supplied with air, and an anode joined to the other surface of the electrolyte membrane and supplied with fuel. In a membrane electrode assembly of a fuel cell having an electrode,
At least one of the cathode electrode and the anode electrode has a base material having gas permeability and a catalyst layer formed on the electrolyte side surface of the base material,
The catalyst layer includes an infinite number of catalyst-supported carbons obtained by supporting a catalyst metal on carbon powder, and a polymer electrolyte that binds the catalyst-supported carbons while being in contact with each other and is bonded to the base material. A hydrophilic layer is formed between the molecular electrolyte and each catalyst-supporting carbon, and the hydrophilic layers communicate with each other.

  In the membrane / electrode assembly of the present invention, since the hydrophilic layer is continuously formed in the catalyst layer, protons easily move along this. In addition, since the polymer electrolyte orients the ion exchange groups of the polymer electrolyte on the hydrophilic layer side, the hydrophilic layer is effectively used for proton transfer. Therefore, in the fuel cell system, the ion-reactive group of the polymer electrolyte is on the catalyst-carrying carbon side between the catalyst-carrying carbon and the polymer electrolyte in the catalyst layer of the anode electrode, the electrolyte membrane, and the cathode electrode. Oriented to form a water channel, and the water channel is formed on the entire surface of the catalyst-carrying carbon, so the amount of water necessary for proton transfer is retained in the water channel and moves well in the water channel, and excess water is required Therefore, a high output can be obtained with light or no humidification.

  The membrane electrode assembly of the present invention can be produced by using the electrode of the present invention for at least one of a cathode electrode and an anode electrode.

  In the membrane electrode assembly of the present invention, it is preferable that at least one of the cathode electrode and the anode electrode has a diffusion layer that is formed on the other surface of the substrate and diffuses air or fuel. As a result, the fuel cell system easily causes a cell reaction, and a high output can be obtained.

  The fuel cell system of the present invention includes the membrane electrode assembly, an air supply unit that supplies air to the cathode electrode, and a fuel supply unit that supplies fuel to the anode electrode.

  In the fuel cell system of the present invention, water moves well at the anode electrode, the electrolyte membrane, and the cathode electrode, and a high output is obtained while being lightly humidified or not humidified.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. In the fuel cell system of the embodiment, a plurality of cells 1 shown in FIG. 14 are used. Each cell 1 includes a membrane electrode assembly (MEA) 10 and a pair of separators 20.

  The MEA 10 includes an electrolyte membrane 11 made of Nafion, an anode electrode 12 integrally joined to one surface of the electrolyte membrane 11, and a cathode electrode 13 joined integrally to the other surface of the electrolyte membrane 11.

  The anode electrode 12 includes an anode catalyst layer 12a provided on the electrolyte membrane 11 side, and an anode diffusion layer 12b joined to the non-electrolyte membrane side of the anode catalyst layer 12a and diffusing hydrogen into the anode catalyst layer 12a.

  The cathode 13 includes a cathode catalyst layer 13a provided on the electrolyte membrane 11 side, and a cathode diffusion layer 13b that is bonded to the non-electrolyte membrane side of the cathode catalyst layer 13a and diffuses air into the cathode catalyst layer 13a.

  Each separator 20 has a hydrogen chamber 21 for supplying hydrogen to the anode electrode 12 on one surface side and an air chamber 22 for supplying air to the cathode electrode 13 on the other surface side.

  Each cell 1 is formed by stacking the MEA 10 and a pair of separators 20 so that the hydrogen chamber 21 faces the anode electrode 12 side and the air chamber 22 faces the cathode electrode 13 side. A stack is formed by sequentially stacking the MEA 10 and the separator 20. Further, the separator 20 common to the anode electrode 12 side and the cathode electrode 13 side is employed. Note that only the hydrogen chamber 21 or the air chamber 22 is formed in the separators 20 at both ends of the stack.

  A hydrogen cylinder 2 communicating with the hydrogen chamber 21 of each cell 1 via a valve (not shown) and a blower 3 communicating with the air chamber 22 of each cell 1 are connected to the stack. The hydrogen cylinder 2 and the hydrogen chamber 21 of the separator 20 are hydrogen supply means for supplying hydrogen to the anode catalyst layer 12a. The air chamber 22 of the blower 3 and the separator 20 is an air supply means for supplying air to the cathode catalyst layer 13a.

  The fuel cell system of the embodiment is characterized by the cathode electrode 13 and the anode electrode 12 of the MEA 10. More specifically, the cathode catalyst layer 13a of the cathode electrode 13 and the anode catalyst layer 12a of the anode electrode 12 are characterized.

  The cathode catalyst layer 13a and the anode catalyst layer 12a are manufactured using a special electrode paste 50 schematically shown in FIG. This electrode paste 50 is manufactured by the following manufacturing method.

  First, as shown in FIG. 1, in Step S1, a commercially available aggregate 31 (see FIG. 4 (A)) made of an infinite number of catalyst-supporting carbons 81 (see FIGS. 15 and 16) was prepared. As shown in FIGS. 15 and 16, each catalyst-supporting carbon 81 is formed by supporting a catalytic metal 81b made of Pt on a substantially spherical carbon powder 81a. In step S2 shown in FIG. 1, the assembly 31 was placed in a vacuum drying chamber at 150 ° C. for 1 hour and vacuum dried. The reason why the catalyst-carrying carbon 81 is vacuum-dried is to remove impurities on the surface of each catalyst-carrying carbon 81 as much as possible and to make it close to hydrophilicity. At this time, the aggregate 31 was not crushed so as not to hinder the contact between the catalyst-carrying carbons 81.

  Thereafter, in step S <b> 3, water 32 was added to the aggregate 31 in an amount eight times that of the aggregate 31. At this time, as shown in FIG. 4A, aggregate 31 and water 32 were added into container 30 to form mixture 40, and when this mixture 40 was allowed to stand, it was left for 60 hours or more. As shown in FIG. 5, the surface of each catalyst-supporting carbon 81 does not originally have a hydroxyl group, which is a hydrophilic group, and each catalyst-supporting carbon 81 has poor wettability. This is because there is no water 32 on the surface. Over time, as shown in FIG. 6, wettability with respect to water 32 was imparted to the catalyst-supporting carbon 81, and an intermediate 41 was obtained.

  It is also possible to perform step S3 as follows. First, a rotation / revolution centrifugal stirrer (manufactured by Keyence Corporation, trade name “Hybrid Mixer HM-500”) having a chamber 35 shown in FIG. 7 was prepared. The chamber 35 includes a container 35a and a lid 35b that seals the container 35a. The chamber 35 revolves around the center point O1 at a high speed and rotates around the axis P extending from the center point O1 at a high speed. To get. A mixture 40 containing the aggregate 31 and water 32 was accommodated in the chamber 35. Then, the mixture 40 was stirred by its own weight by rotating the chamber 35 while applying centrifugal force to the mixture 40 by revolving the chamber 35. In this way, air was forcibly removed from the surface of each catalyst-supporting carbon 81, and the gaps between the carbon powders 81a were filled with water, thereby obtaining an intermediate 41 shown in FIG. At this time, since foreign substances such as balls and propellers are not used for applying centrifugal force and stirring, contact between the catalyst-supporting carbons 81 is not hindered.

  Then, in step S4 shown in FIG. 1, as shown in FIG. 4B, the intermediate 41 was mixed with a solution composed of Nafion as the polymer electrolyte 82, alcohol, and water. At this time, an ultrasonic vibration device may be used, or the chamber 35 of a rotating / revolving centrifugal stirrer may be used. At this time, as shown in FIG. 8, each catalyst-supporting carbon 81 has wettability to water, so that the polymer electrolyte 82 is formed from the sulfone group of the polymer electrolyte 82 itself on the side of each catalyst-supporting carbon 81. The resulting ion exchange group 82a was oriented. Thus, as shown in FIGS. 4 (C) and 9, an electrode paste in which hydrophilic layers 72 continuous with water 32 are formed between the catalyst-supporting carbon 81 and the polymer electrolyte 82 that are in contact with each other during power generation. 50 was obtained.

  On the other hand, in step S5 shown in FIG. 2, a carbon cloth was produced as a base material having gas permeability. A diffusion layer having a carbon cloth as a base material and a water repellent layer made of a mixture of carbon black and PTFE on both sides was prepared. Thereafter, in step S6, the cathode catalyst layer 13a and the anode catalyst layer 12a were printed using the electrode paste 50. In step S7, the substrate after printing was dried, and the alcohol and water in the solution were evaporated to obtain the cathode 13 and the anode 12.

  FIG. 10 shows a photomicrograph of the cathode diffusion layer 13b or anode diffusion layer 12b magnified 50 times, and FIG. 11 shows a photomicrograph of 50,000 times. 10 and 11, it can be seen that the cathode diffusion layer 13b or the anode diffusion layer 12b has innumerable fine holes. For this reason, it turns out that oxygen and hydrogen can easily pass through the cathode diffusion layer 13b and the anode diffusion layer 12b.

  In step S8, the electrolyte membrane 11 was cut to a certain size. In step S9, the appearance of the cathode electrode 13 and the anode electrode 12 was inspected, and in step S10, the cathode electrode 13 and the anode electrode 12 were also cut to a certain size.

  Thereafter, in step S11, the anode electrode 12, the electrolyte membrane 11 and the cathode electrode 13 were laminated in this order, and hot-pressed at 140 ° C. and a pressing force of 60 kgf. In this way, MEA10 was obtained. In step S12, the size of the MEA 10 is cut. In step S13, the MEA 10 is inspected. In step S14, the MEA 10 is completed.

  FIG. 12 shows a photomicrograph in which the cross section of the MEA 10 is enlarged 20,000 times. Further, FIG. 13 shows a microphotograph at a magnification of 1,000,000 of the cathode catalyst layer 13a or the anode catalyst layer 12a. Although not necessarily clear from FIGS. 12 and 13, if the cathode catalyst layer 13a of the cathode electrode 13 and the anode catalyst layer 12a of the anode electrode 12 are manufactured as described above, in these cases, FIG. It is inferred that the contact between the catalyst-supporting carbons 81 is maintained and a hydrophilic layer 72 is formed between the polymer electrolyte 82 and each of the catalyst-supporting carbons 81 by the water 32 as shown in FIG. The For this reason, protons generated in the anode catalyst layer 12a travel along the formed hydrophilic layer 72 and move in the anode catalyst layer 12a, so that the ionic resistance in the anode catalyst layer 12a is lowered, resulting in the anode catalyst layer. It is thought that it is easy to move in 12a. Then, as shown in FIG. 17, these protons are low because the ionic resistance from the anode catalyst layer 12 a to the electrolyte membrane 11 is also communicated with the hydrophilic layer 72, and easily move into the electrolyte membrane 11. Since it moves through the hydrophilic layer 72 and moves in the cathode catalyst layer 13a, the ionic resistance in the cathode catalyst layer 13a is lowered, and as a result, it is considered that it is likely to move in the cathode catalyst layer 13a. Thus, it is considered that protons easily move through the hydrophilic layer 72 in the anode electrode 12 and the cathode electrode 13 of the MEA 10.

  Furthermore, the produced water produced by the catalyst metal 81b of the cathode catalyst layer 13a quickly diffuses back to the anode electrode 12 side through the communicating hydrophilic layer 72. For this reason, in particular, dry-up of the electrolyte membrane 11 and the anode catalyst layer 12a during the low humidification operation can be effectively suppressed, and high power generation performance can be maintained.

  Moreover, in the cathode catalyst layer 13a and the anode catalyst layer 12a, as shown in FIG. 16, it is inferred that the polymer electrolyte 82 having polarity is suitably oriented by the sulfone group. For this reason, a sulfone group is directed on the surfaces of the carbon powder 81a and the catalyst metal 81b, and a hydrophilic group 72 is formed between the carbon powder 81a and the sulfone group. Thus, in this MEA 10, it is considered that the hydrophilic layer 72 is effectively utilized for proton movement.

Thus, the hydrophilic layer 72 is considered to be formed in a thin film shape by the hydroxyl group generated on the surface of each catalyst-supporting carbon 81 and the ion exchange group 82a of the polymer electrolyte 82 (PFF (Proton Film Flow) structure). ). For this reason, in this fuel cell system, H ₃ O moves well through the thin-film hydrophilic group 72 at the anode electrode 12, the electrolyte membrane 11, and the cathode electrode 13 of the MEA 10. Thus, since the hydrophilic layer 72 is formed in advance as a water passage, the supply of excess water from the outside to the anode electrode 12 and the electrolyte membrane 11 can be reduced, and flooding due to excess water is unlikely to occur. Therefore, a high output can be obtained while being lightly humidified or non-humidified.

  For the fuel cell system of the example and the fuel cell system of the comparative example, the non-humidifying operation performance was compared. The fuel cell system of the comparative example uses a conventional MEA90. In the conventional MEA 90, a catalyst-supported carbon powder is mixed with a solvent (water / ethylene glycol or the like), and then dispersed in an ion exchange resin and a solvent to prepare a paste. An electrode and a cathode electrode are produced, and an electrolyte membrane is sandwiched between the anode electrode and the cathode electrode. Other configurations of the fuel cell system of the comparative example are the same as those of the fuel cell system of the example.

The test conditions are an operating temperature of 70 ° C., a load of 0.7 A / cm ² , an air stoichiometric ratio of “4”, and a hydrogen stoichiometric ratio of “1.3”. The operating pressures of hydrogen and air were normal pressure and flowed in a countercurrent manner. The results are shown in FIG.

FIG. 18 shows the following in the fuel cell system of the example. First, the resistance is stable between 0.1 and 0.15 (Ω · cm ² ), which is the same level as that measured under full humidification conditions. On the other hand, with respect to the voltage, there is a characteristic that power is stably generated between 0.5 and 0.6 (V). These two results are evidence of a phenomenon in which the back diffusion of product water is good. On the other hand, it can be seen that the MEA 90 became inoperable immediately after operation due to lack of water.

  Therefore, according to the fuel cell system of the embodiment, a high output can be obtained even with light humidification or non-humidification, so that the running cost can be reduced.

  The present invention can be used for a moving power source for an electric vehicle or the like, or a stationary power source.

3 is a flowchart showing a part of the manufacturing method according to the fuel cell system of the embodiment. 3 is a flowchart showing a part of the manufacturing method according to the fuel cell system of the embodiment. 3 is a flowchart showing a part of the manufacturing method according to the fuel cell system of the embodiment. A part of manufacturing method of the fuel cell system of an Example is shown, FIG. (A) is a schematic side view which shows the state which adds water to the aggregate | assembly of catalyst carrying | support carbon, FIG. (B) is a polymer electrolyte in the intermediate The schematic side view which shows the state to add, FIG. (C) is a schematic side view which shows the paste for electrodes. It is an expansion schematic diagram of a mixture. It is an expansion schematic diagram of an intermediate. It is a schematic diagram of the chamber of a rotation / revolution type centrifugal stirrer. It is an expansion schematic diagram which shows an intermediate body and a polymer electrolyte. It is an expansion schematic diagram of the paste for electrodes. It is the microscope picture which expanded the cross section of the cathode pole or the anode pole by 50 times. It is a 50,000 times microscope picture of the part of a cathode catalyst layer or an anode catalyst layer. It is the microscope picture which expanded the cross section of MEA 20,000 times. It is a 1 million times microscope picture of the part of a cathode catalyst layer or an anode catalyst layer. It is a schematic cross section which shows the cell of an Example. It is a model expanded sectional view which shows the cathode catalyst layer or anode catalyst layer of an Example. FIG. 16 is a schematic enlarged cross-sectional view of a portion XIV in FIG. 15 according to the fuel cell system of the example. It is a model expanded sectional view which shows MEA of an Example. It is a graph which shows the non-humidification operation | movement performance in the fuel cell system of an Example and a comparative example concerning a test. It is a schematic cross section which shows MEA of the past and a comparative example. It is a model expanded sectional view which shows MEA of the past and a comparative example.

Explanation of symbols

81a ... carbon powder 81b ... catalyst metal 81 ... catalyst-supported carbon 82 ... polymer electrolyte 50 ... electrode paste 32 ... water 72 ... hydrophilic layer 12, 13 ... electrode (12 ... anode electrode, 13 ... cathode electrode)
12a, 13a ... catalyst layer (12a ... anode catalyst layer, 13a ... cathode catalyst layer)
DESCRIPTION OF SYMBOLS 11 ... Electrolyte membrane 10 ... Membrane electrode assembly (MEA)
12b ... Anode diffusion layer 13b ... Cathode diffusion layer 3, 22 ... Air supply means, hydrogen supply means (3 ... blower, 22 ... air chamber)
2, 21 ... Fuel supply means (2 ... Hydrogen cylinder, 21 ... Hydrogen chamber)

Claims (6)

A gas-permeable base material and a catalyst layer formed on one surface of the base material, the catalyst layer comprising countless catalyst-supporting carbons obtained by supporting a catalyst metal on carbon powder, and each of the catalysts An electrode of a fuel cell comprising a polymer electrolyte that binds supported carbon to each other and binds to the substrate,
The catalyst layer includes the polymer electrolyte and the catalyst-supporting carbons that are in contact with each other. A hydrophilic layer is formed between the polymer electrolyte and the catalyst-supporting carbon, and the hydrophilic layers communicate with each other. A fuel cell electrode characterized by comprising:   2. The fuel cell electrode according to claim 1, wherein the hydrophilic layer is formed in a thin film shape by orienting ion exchange groups of the polymer electrolyte toward the catalyst-carrying carbon. In a membrane electrode assembly of a fuel cell having an electrolyte membrane, a cathode electrode joined to one surface of the electrolyte membrane and supplied with air, and an anode electrode joined to the other surface of the electrolyte membrane and supplied with fuel ,
At least one of the cathode electrode and the anode electrode has a base material having gas permeability and a catalyst layer formed on the electrolyte side surface of the base material,
The catalyst layer includes an infinite number of catalyst-supported carbons obtained by supporting a catalyst metal on carbon powder, and a polymer electrolyte that binds the catalyst-supported carbons while being in contact with each other and is bonded to the base material. A fuel cell membrane electrode assembly, wherein a hydrophilic layer is formed between a molecular electrolyte and each of the catalyst-supporting carbons, and the hydrophilic layers communicate with each other.   The membrane electrode assembly of a fuel cell according to claim 3, wherein the hydrophilic layer is formed in a thin film shape by orienting ion exchange groups of the polymer electrolyte toward the catalyst-supporting carbon.   5. The fuel cell membrane according to claim 3, wherein at least one of the cathode electrode and the anode electrode has a diffusion layer formed on the other surface of the base material and diffusing the air or the fuel. Electrode assembly.   6. A fuel comprising the membrane electrode assembly according to claim 3, 4 or 5, an air supply means for supplying air to the cathode electrode, and a fuel supply means for supplying the fuel to the anode electrode. Battery system.