JP2020087813A - Solid polymer fuel cell - Google Patents

Abstract

To provide a solid polymer fuel cell having a fuel electrode and an air electrode which indicate an excellent catalytic activity (catalytic action) in regardless to have less content amount of a platinum group metal.SOLUTION: A fuel electrode and an air electrode used for a solid polymer fuel cell 10, are formed by at least one kind of a less platinum group metal selected from each kind of the platinum group metals, and at least two kinds of transition metals. Each of the fuel electrode and the air electrode are a thin-plate like electrode having a microporous structure in which multiple fine pores are formed by adding a prescribed pore formation material into a metal fine powder mixture obtained by uniformly mixing and scattering a transition metal fine powder body obtained by finely crushing at least one kind platinum group metal to be selected, a transition metal fine powder body obtained by finely crushing at least two kinds transition metals to be selected, and a prescribed binder, forms the metal fine powder mixture into which the pore formation material is added to a thin-plate shape having a prescribed area, and performs defatting and sintering of the metal fine powder formation material formed in the thin-plate shape of the prescribed area.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a polymer electrolyte fuel cell including a cell stack having a plurality of cells.

Solid polymer electrolyte membrane, anode electrode and cathode electrode sandwiching the solid polymer electrolyte membrane from both sides, fuel container containing liquid fuel, gas-liquid separating porous material provided between the anode electrode and cathode electrode A perforated fixing plate disposed on the cathode electrode side has an aperture ratio of a perforated fixing plate having a fuel vaporized layer composed of a body and a perforated fixing plate sandwiching the fuel vaporized layer from both sides. A solid polymer fuel cell having a larger aperture ratio is disclosed (see Patent Document 1).

JP, 2011-222119, A

The method for producing the cathode electrode and the anode electrode of the solid polymer fuel cell disclosed in Patent Document 1 is as follows. A catalyst-supporting carbon microparticle was prepared by supporting 55% by weight of platinum microparticles having a particle diameter in the range of 3 to 5 nm on carbon particles, and an appropriate amount of a 5% by weight Nafion solution was added to 1 g of the catalyst-supporting carbon microparticle and stirred, Make a catalyst paste for the cathode electrode. A catalyst paste for a cathode electrode is applied on a carbon paper as a base material in an amount of 8 mg/cm ² , and then dried to prepare a 4 cm×4 cm cathode electrode. Next, in place of the platinum fine particles, platinum (Pt)-ruthenium (Ru) alloy fine particles (Ru ratio of 60 at%) having a particle diameter in the range of 3 to 5 nm were loaded on the catalyst-supporting carbon fine particles in a weight ratio of 55%. Then, an appropriate amount of a 5 wt% Nafion solution is added to 1 g of the catalyst-supporting carbon fine particles and the mixture is stirred to prepare a catalyst paste for an anode electrode. A catalyst paste for an anode electrode is applied on a carbon paper as a base material in an amount of 8 mg/cm ² , and then dried to prepare a 4 cm×4 cm anode electrode.

Various platinum-supported carbons are widely used as electrode catalysts for polymer electrolyte fuel cells. However, since platinum is a precious metal and is a rare metal resource with a limited production amount, it is required to suppress its use. Furthermore, in order to spread the polymer electrolyte fuel cell in the future, it is required to reduce the content of expensive platinum as much as possible and to develop an electrode using a metal other than platinum together with a small amount of platinum.

An object of the present invention is to provide a fuel electrode and an air electrode which can minimize the platinum group metal content and have excellent catalytic activity (catalytic action) in spite of the low platinum group metal content. Another object of the present invention is to provide a polymer electrolyte fuel cell capable of generating sufficient electricity by using the fuel electrode and the air electrode and supplying sufficient electric energy to a load.

The polymer electrolyte fuel cell of the present invention for solving the above-mentioned problems comprises a cell stack having a plurality of cells, and the cells are electrodes positioned between a fuel electrode and an air electrode, and between the fuel electrode and the air electrode. It is formed of a bonded film and a separator located outside the fuel electrode and outside the air electrode, and the fuel electrode and the air electrode are at least one small amount of platinum group metal selected from various platinum group metals. And at least two kinds of transition metals selected from various kinds of transition metals, and the fuel electrode and the air electrode were selected from finely pulverized platinum group metal powder of at least one selected platinum group metal. A fine metal powder mixture obtained by adding a predetermined pore forming material to a fine metal powder mixture obtained by uniformly mixing and dispersing a fine transition metal powder obtained by finely pulverizing at least two kinds of transition metals and a predetermined binder, and adding the fine pore forming material. Is a thin plate electrode having a microporous structure in which a large number of fine pores are formed by degreasing and sintering a metal fine powder molded product formed into a thin plate shape having a predetermined area It is characterized by

As an example of the polymer electrolyte fuel cell of the present invention, in the fuel electrode and the air electrode, various types are used so that the composite work function of the work functions of at least two selected transition metals approximates to the work function of the platinum group metal. At least two kinds of transition metals are selected from among the above transition metals.

As another example of the polymer electrolyte fuel cell of the present invention, the average diameter of the pores formed in the fuel electrode and the air electrode is in the range of 1 to 100 μm.

As another example of the polymer electrolyte fuel cell of the present invention, the thickness dimension of the fuel electrode and the thickness dimension of the air electrode are in the range of 0.03 mm to 1.5 mm.

As another example of the polymer electrolyte fuel cell of the present invention, the platinum group metal is Pt (platinum), the transition metals are Ni (nickel) and Fe (iron), and the fuel electrode and the air electrode are Then, in order that the composite work function of the work function of Ni and the work function of Fe approximates the work function of the platinum group metal, the weight ratio of the platinum group metal fine powder of Pt to the total weight of the metal fine powder mixture and the Ni A weight ratio of the transition metal fine powder to the total weight of the metal fine powder mixture and a weight ratio of Fe to the total weight of the transition metal fine powder to the metal fine powder mixture are defined.

As another example of the polymer electrolyte fuel cell of the present invention, the weight ratio of the platinum group metal fine powder of Pt to the total weight of the metal fine powder mixture is in the range of 4 to 10%, and the transition metal fine powder of Ni is The weight ratio of the metal fine powder mixture to the total weight is in the range of 45% to 48%, and the weight ratio of the transition metal fine powder of Fe to the total weight of the metal fine powder mixture is in the range of 45% to 48%.

As another example of the polymer electrolyte fuel cell of the present invention, the porosity of the fuel electrode and the air electrode formed in the shape of a microporous thin plate is in the range of 70% to 85%.

As another example of the polymer electrolyte fuel cell of the present invention, the density of the fuel electrode and the air electrode, which is formed into a thin sheet of microporous structure, the range of 6.0g ^/ cm ² ~8.0g / cm 2 is there.

As another example of the polymer electrolyte fuel cell of the present invention, the particle size of the platinum group metal fine powder of the platinum group metal and the particle size of the transition metal fine powder of the transition metal are in the range of 1 μm to 100 μm.

As another example of the polymer electrolyte fuel cell of the present invention, in the polymer electrolyte fuel cell, the hydrogen atmosphere supplied to the fuel electrode has a relative humidity of 95% to 100% and a hydrogen temperature of 45%. It is in the range of ℃ to 55 ℃.

As another example of the polymer electrolyte fuel cell of the present invention, in the polymer electrolyte fuel cell, the supply pressure of hydrogen supplied to the fuel electrode is in the range of +0.06 MPa to +0.08 MPa.

According to the polymer electrolyte fuel cell of the present invention, the fuel electrode and the air electrode used therein are selected from at least one platinum group metal selected from various platinum group metals and various transition metals. Platinum group metal fine powder formed of at least two kinds of transition metals and finely pulverized at least one selected platinum group metal and transition metal fine powder obtained by finely pulverized at least two kinds of selected transition metals Add a specified pore forming material to the metal fine powder mixture that is uniformly mixed and dispersed with the binder of, and mold the metal fine powder mixture with the added pore forming material into a thin plate shape with a predetermined area, Since it is a thin plate electrode with a microporous structure in which a large number of fine pores are formed by degreasing and sintering the formed metal fine powder molded product, by using a transition metal other than the platinum group metal, platinum It is possible to reduce the content of group metals as much as possible, and to generate sufficient electricity by using the fuel electrode and air electrode that utilize the catalytic activity of platinum group metals and the catalytic activity of transition metals. It is possible to supply sufficient electric energy to the load connected to the fuel cell.

In the fuel electrode and the air electrode, at least two transition metals are selected from various transition metals so that the composite work function of the work functions of the selected at least two transition metals approximates to the work function of the platinum group metal. In the polymer electrolyte fuel cell selected, at least two kinds of transition metals are selected from various kinds of transition metals so that the synthetic work function approximates the work function of platinum group metals. Although the fuel electrode and the air electrode have almost the same work function as the platinum-supported electrode, the catalytic activity (catalyst action) ), it is possible to generate sufficient electricity by using a fuel electrode and an air electrode which contain at least two selected transition metals and have excellent catalytic activity, and can be applied to a load connected to a fuel cell. Sufficient electric energy can be supplied.

In the polymer electrolyte fuel cell in which the average diameter of the pores formed in the fuel electrode and the air electrode is in the range of 1 to 100 μm, the average diameter of the pores formed in the fuel electrode and the air electrode is in the range of 1 to 100 μm. Therefore, a large number of pores are formed per unit volume of the fuel electrode and the air electrode, and the specific surface area of the fuel electrode and the air electrode can be increased. The contact surface of the electrode can be widely contacted, and the catalytic action of the fuel electrode and the air electrode can be utilized to the maximum. The polymer electrolyte fuel cell can generate sufficient electricity by using a fuel electrode and an air electrode having pores with an average diameter in the range of 1 to 100 μm and having excellent catalytic activity, and can be connected to the fuel cell. Sufficient electrical energy can be supplied to the loaded load.

The polymer electrolyte fuel cell in which the thickness dimension of the fuel electrode and the thickness dimension of the air electrode are in the range of 0.03 mm to 1.5 mm can be achieved by adjusting the thickness dimensions of the fuel electrode and the air electrode within the above range. Also, the electric resistance of the air electrode can be reduced, and the current can be smoothly passed through the fuel electrode and the air electrode. The polymer electrolyte fuel cell has substantially the same catalytic activity (catalytic action) as an electrode in which the fuel electrode and the air electrode carry platinum, and the electric resistance of the fuel electrode and the air electrode is small, so that Since the current flows smoothly, it is possible to generate sufficient electricity using the fuel electrode and air electrode, which have excellent catalytic activity and low potential resistance, and generate sufficient electric energy for the load connected to the fuel cell. Can be supplied.

The platinum group metal is Pt (platinum), the transition metals are Ni (nickel) and Fe (iron), and the combined work function of the work function of Ni and the work function of Fe is close to the work function of the platinum group metal. Thus, the weight ratio of Pt platinum group metal fine powder to the total weight of the metal fine powder mixture and the weight ratio of Ni transition metal fine powder to the total weight of the metal fine powder mixture and Fe transition metal fine powder to the metal fine powder The polymer electrolyte fuel cell, in which the weight ratio to the total weight of the body mixture is defined, has a Pt based on the total weight of the metal fine powder mixture such that the synthetic work function of the transition metal approximates the work function of the platinum group metal. Of the platinum group metal fine powder, the weight ratio of the Ni transition metal fine powder to the total weight of the metal fine powder mixture, and the weight ratio of the Fe transition metal fine powder to the total weight of the metal fine powder mixture are determined. Therefore, the fuel electrode and the air electrode have almost the same work function as the electrode supporting platinum, the fuel electrode and the air electrode have excellent catalytic activity (catalytic action), and the fuel electrode and the air electrode support platinum. By exhibiting the same catalytic activity (catalytic action) as the electrode, sufficient electricity can be generated using the fuel electrode and the air electrode, and sufficient electric energy can be supplied to the load connected to the fuel cell. Can be supplied. In the polymer electrolyte fuel cell, the fuel electrode and the air electrode contain Ni (nickel) and Fe (iron), and the content of Pt (platinum) is small. Therefore, the material cost of the fuel electrode and the air electrode should be reduced. Therefore, the polymer electrolyte fuel cell can be manufactured at low cost, and the operation cost of the polymer electrolyte fuel cell can be reduced.

The weight ratio of Pt platinum group metal fine powder to the total weight of the metal fine powder mixture is in the range of 4 to 10%, and the weight ratio of Ni transition metal fine powder to the total weight of the metal fine powder mixture is 45% to 48%. In the range, the weight ratio of the transition metal fine powder of Fe to the total weight of the fine metal powder mixture is in the range of 45% to 48%, the polymer electrolyte fuel cell has a synthetic work function close to that of the platinum group metal. Ni (nickel) and Fe (iron) are selected, and the weight ratio of the platinum group metal fine powder of Pt to the total weight of the fine metal powder mixture and the weight of the transition metal fine powder of Ni to the total weight of the fine metal powder mixture are selected. By adjusting the ratio of the weight ratio of the transition metal fine powder of Fe to the total weight of the mixture of fine metal powder to the above range, the composite work function of the work functions of the transition metal fine powder of Ni and the transition metal fine powder of Fe can be platinum. It can be approximated to the work function of group metals, and despite its low Pt content, the fuel electrode and air electrode have excellent catalytic activity (catalyst action), and the fuel electrode and air electrode carry platinum. By exhibiting substantially the same catalytic activity (catalytic action) as the electrode, it is possible to generate sufficient electricity using its fuel electrode and air electrode, and to generate sufficient electric energy for the load connected to the fuel cell. Can be supplied. In the polymer electrolyte fuel cell, the fuel electrode and the air electrode include Ni (nickel) and Fe (iron) in the weight ratios described above, and the weight ratio of Pt (platinum) to the total weight of the fine metal powder mixture is small. Since the content of (platinum) is low, the material cost of the fuel electrode and air electrode can be reduced, the polymer electrolyte fuel cell can be manufactured at low cost, and the operation cost of the polymer electrolyte fuel cell can be reduced. Can be lowered.

A polymer electrolyte fuel cell having a porosity of a fuel electrode and an air electrode formed in a thin plate having a microporous structure in the range of 70% to 85% has a porosity of the fuel electrode and the air electrode within the above range. In order to increase the specific surface area of the fuel electrode and the air electrode, the fuel electrode and the air electrode are molded into a porous structure (a microporous structure having an average pore diameter of 1 to 100 μm) having a large number of fine pores (passage holes). It becomes possible to bring the gas into wide contact with the contact surface of the pores of the fuel electrode and the air electrode while allowing the gas to flow through the pores, and the catalyst is almost the same as the electrode in which the fuel electrode and the air electrode carry platinum. Generating sufficient electricity by using the fuel electrode and the air electrode that reliably exhibit the activity (catalyst action) and can fully and reliably utilize the catalyst function and have excellent catalytic activity (catalyst action). It is possible to supply sufficient electric energy to the load connected to the fuel cell.

Polymer electrolyte fuel cell density of the fuel electrode and an air electrode which is formed into a thin microporous structure is in the range of 6.0g ^/ cm ² ~8.0g / cm 2, the density of the fuel electrode and an air electrode Within the above range, the fuel electrode and the air electrode are molded into a porous structure (a microporous structure having an average pore diameter of 1 to 100 μm) having a large number of fine pores (passage holes), and the ratio of the fuel electrode and the air electrode is increased. The surface area can be increased, and it becomes possible to allow the gas to contact a wide range of contact surfaces of the fuel electrode and the air electrode in the pores while allowing the gas to flow through these pores, and the fuel electrode and the air electrode support platinum. Uses a fuel electrode and an air electrode that exhibit a catalytic activity (catalyst action) that is almost the same as the above, and can fully and reliably utilize the catalytic function, and that has excellent catalytic activity (catalyst action). Sufficient electricity can be generated, and sufficient electric energy can be supplied to the load connected to the fuel cell.

A polymer electrolyte fuel cell in which the particle size of the platinum group metal fine powder of the platinum group metal and the particle size of the transition metal fine powder of the transition metal are in the range of 1 μm to 100 μm is a platinum group metal fine powder of platinum group metal or a platinum group metal fine powder. By making the particle size of the transition metal fine powder of the transition metal within the above range, the fuel electrode and the air electrode are porous with a large number of fine pores (passage holes) (microporous structure having an average pore diameter of 1 to 100 μm). It is possible to increase the specific surface area of the fuel electrode and the air electrode, and it becomes possible to bring the gas into wide contact with the contact surfaces of the pores of the fuel electrode and the air electrode while allowing the gas to flow through the pores. An excellent catalytic activity (catalytic action) because the fuel electrode and the air electrode surely exhibit the same catalytic activity (catalytic action) as the electrode supporting platinum, and the catalytic function can be used sufficiently and reliably. Sufficient electricity can be generated by using the fuel electrode and the air electrode having the above, and sufficient electric energy can be supplied to the load connected to the fuel cell.

The hydrogen atmosphere supplied to the fuel electrode has a relative humidity in the range of 95% to 100%, and the hydrogen temperature is in the range of 45°C to 55°C. By supplying hydrogen to the fuel electrode at a temperature of 45°C to 55°C while supplying hydrogen to the fuel electrode in the atmosphere of, the catalytic activity of the fuel electrode is increased, the electromotive force of the fuel cell is improved, and the fuel electrode is improved. It is possible to reliably generate sufficient electricity by using the air electrode and the air electrode, and to reliably supply sufficient electric energy to the load connected to the fuel cell.

The polymer electrolyte fuel cell in which the supply pressure of hydrogen supplied to the fuel electrode is in the range of +0.06 MPa to +0.08 MPa can supply hydrogen to the fuel electrode at a supply pressure of +0.06 MPa to +0.08 MPa. , The catalytic activity of the fuel electrode is increased, the electromotive force of the fuel cell is improved, and it is possible to reliably generate sufficient electricity using the fuel electrode and the air electrode, which is sufficient for the load connected to the fuel cell. Electric energy can be reliably supplied.

The perspective view of the polymer electrolyte fuel cell shown as an example. FIG. 3 is an exploded perspective view showing an example of cells forming a cell stack. Side view of the cell. The perspective view of the fuel electrode and air electrode shown as an example. The partially expanded front view shown as an example of a fuel electrode and an air electrode. The figure explaining the electric power generation of a polymer electrolyte fuel cell. The figure which shows the result of the electromotive force test of a fuel electrode and an air electrode. The figure which shows the result of the IV characteristic test of a fuel electrode and an air electrode. FIG. 3 is a diagram illustrating a method for manufacturing a fuel electrode and an air electrode used in a polymer electrolyte fuel cell.

The polymer electrolyte fuel cell according to the present invention will be described in detail with reference to the accompanying drawings such as FIG. 1 which is a perspective view of the polymer electrolyte fuel cell 10 as an example. 2 is an exploded perspective view showing an example of the cell 11 forming the cell stack 12, and FIG. 3 is a side view of the cell 11. FIG. 4 is a perspective view of the fuel electrode 13 and the air electrode 14 shown as an example, and FIG. 5 is a partial enlarged view showing an example of the fuel electrode 13 and the air electrode 14. In FIG. 4, the thickness direction is indicated by arrow X, and the radial direction is indicated by arrow Y.

The polymer electrolyte fuel cell 10 includes a cell stack 12 (fuel cell stack) having a plurality of cells 11, and generates electric energy by supplying hydrogen and oxygen. In the cell stack 12, a plurality of cells 11 (single cells) overlap in one direction and are connected in series. As an example of the cell 11, as shown in FIG. 2, a fuel electrode 13 (anode) and an air electrode 14 (cathode), and a solid polymer electrolyte membrane 15 positioned (interposed) between the fuel electrode 13 and the air electrode 14. (Electrode assembly membrane) (fluorine-based ion exchange membrane having sulfonic acid group), separator 16 (bipolar plate) located outside the fuel electrode 13 in the thickness direction, and separator 17 located outside air electrode 14 in the thickness direction. (Bipolar plate).

The separators 16 and 17 are provided with engraved (engraved) supply channels for reaction gas (hydrogen, oxygen, etc.). In the cell 11, as shown in FIG. 3, the fuel electrode 13, the air electrode 14, and the solid polymer electrolyte membrane 15 are overlapped and integrated in the thickness direction to form a membrane/electrode assembly 18 (Membrane Electrode Assembly, MEA). The membrane/electrode assembly 18 is sandwiched by the separators 16 and 17. In the membrane/electrode assembly 18, the surface of the fuel electrode 13 is closely attached to one surface of the solid polymer electrolyte membrane 15 by hot pressing, and the surface of the air electrode 14 is attached to the other surface of the solid polymer electrolyte membrane 15. It is in close contact with no gap. The solid polymer electrolyte membrane 15 has proton conductivity and no electron conductivity.

A gas diffusion layer 19 is formed between the fuel electrode 13 and the separator 16, and a gas diffusion layer 20 is formed between the air electrode 14 and the separator 17. Gas seals 21 are installed between the fuel electrode 13 and the separator 16 and above and below the gas diffusion layer 20. Gas seals 22 are installed between the air electrode 14 and the separator 17 and above and below the gas diffusion layer 20.

The fuel electrode 13 (catalyst electrode) and the air electrode 14 (catalyst electrode) used for the polymer electrolyte fuel cell 10 (cell 11) have a front surface 23 and a rear surface 24, and have a predetermined area and a predetermined thickness dimension L1. It has a planar shape of a quadrangle. The fuel electrode 13 and the air electrode 14 are porous (microporous structure) thin plate electrodes 26 (thin plate foam metal electrodes) having a large number of fine pores 25 (flow paths) (continuous and independent passage holes). Gas flows through the pores 25. The planar shapes of the fuel electrode 13 and the air electrode 14 are not particularly limited, and may be formed in any other planar shape such as a circle, an ellipse, etc., in addition to the quadrangle, depending on the application.

The fuel electrode 13 and the air electrode 14 (the thin plate-shaped electrode 26 having a microporous structure) are made of at least two kinds of metal selected from powder-processed platinum group metal 31 and powder-processed transition metal 32. And a transition metal 32. As the platinum group metal 31, platinum (Pt), palladium (Pb), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os) can be used. At least one of them is used for the platinum group metal 31. As the transition metal 32, 3d transition metal or 4d transition metal is used. As the 3d transition metal, Ti (titanium), Cr (chromium), Cu (copper), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Zn (zinc) is used. Nb (niobium), Mo (molybdenum), and Ag (silver) are used as the 4d transition metal. At least two of them are used for the transition metal 32.

In the fuel electrode 13 and the air electrode 14, the composite work function of the work functions (energy required to extract electrons from the substance) of at least two kinds of selected transition metals 32 is approximated to the work function of the platinum group metal. , At least two kinds of transition metals 32 are selected from the transition metals 32. The work function of platinum is 5.65 (eV). The work function of Ti is 4.14 (eV), the work function of Cr is 4.5 (eV), the work function of Cu is 5.10 (eV), and the work function of Mn is 4.1 (eV). ), the work function of Fe is 4.67 (eV), the work function of Co is 5.0 (eV), the work function of Ni is 5.22 (eV), and the work function of Zn is 3.63. (EV) and Nb have work functions of 4.01 (eV), Mo has a work function of 4.45 (eV), and Ag has a work function of 4.31 (eV).

The fuel electrode 13 and the air electrode 14 are platinum group metal fine powder of the platinum group metal 31 (Pt (platinum) processed into fine powder, Pb (palladium) processed into fine powder, Rh(processed into fine powder). Rhodium), finely powdered Ru (ruthenium), finely powdered Ir (iridium), finely powdered Os (osmium)), and at least two kinds selected from various transition metals 32 Transition metal fine powder of those transition metals 32 (Ti (titanium) processed into fine powder, Cr (chrome) processed into fine powder, Cu (copper) processed into fine powder, processed into fine powder) Mn (manganese), finely powdered Fe (iron), finely powdered Co (cobalt), finely powdered Ni (nickel), finely powdered Zn (zinc), fine powder Uniformly processed Nb (niobium), finely powdered Mo (molybdenum), and finely powdered Ag (silver), and a predetermined binder 33 (powder-like resin-based binder) A mixed/dispersed metal fine powder mixture 41 is prepared, a predetermined pore forming material 40 (foaming agent) is added (added) to the metal fine powder mixture 41, and the metal fine powder mixture 41 added with the pore forming material 40 has a predetermined area. Is formed by extruding (extruding or injection molding) a thin plate-like metal fine powder molded product 42, degreasing and sintering (firing) the metal fine powder molded product 42 at a predetermined temperature. (See Figure 9).

In the fuel electrode 13 and the air electrode 14, the platinum group metal 31 is a metal of the platinum group metal fine powder so that the combined work function of the work functions of the two selected transition metals 32 approximates the work function of the platinum group metal. The weight ratio of the fine powder mixture 41 to the total weight is determined, and the weight ratio of the transition metal fine powder of the transition metal 32 to the total weight of the metal fine powder mixture 41 is determined.

Specifically, the weight ratio of the platinum group metal 31 of the platinum group metal fine powder to the total weight (100%) of the metal fine powder mixture 41 is in the range of 4% to 10%, preferably 6% to 8%. And the weight ratio of one kind of transition metal fine powder among the selected transition metals 32 to the total weight (100%) of the metal fine powder mixture 41 is in the range of 45% to 48%. The weight ratio of the other transition metal fine powder of the metal 32 to the total weight (100%) of the fine metal powder mixture 41 is in the range of 45% to 48%.

Weight ratio of platinum group metal 31 to platinum group metal fine powder, weight ratio of transition metal fine powder to one selected transition metal 32, weight weight of transition metal fine powder to another selected one type of transition metal 32 If the ratio is out of the above range, the composite work function of the transition metal fine powders of the transition metals 32 cannot be approximated to the work function of the platinum group metal, and the metal fine powder mixture 41 formed by molding the metal fine powder mixture 41 is formed. The electrode 10 made by degreasing and sintering (sintering) cannot exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting platinum.

In the polymer electrolyte fuel cell 17, the weight ratio of the platinum group metal 31 fine powder to the total weight of the metal fine powder mixture 41, and the total weight of the selected one kind of transition metal 32 fine powder of the metal fine powder mixture 41. The weight ratio to the total weight of the metal fine powder mixture 41 of the fine powder of the other selected one kind of transition metal 32 is within the above range, so that the work of at least two kinds of selected transition metals 32 is achieved. The composite work function of the functions can be approximated to the work function of the platinum group metal, and the fuel electrode 13 and the air electrode 14 have substantially the same work function as the electrode supporting platinum, and the fuel electrode 13 and the air electrode 14 are excellent. Since the fuel electrode 13 and the air electrode 14 exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting platinum, the fuel electrode 13 and the air electrode 14 can be used. As a result, sufficient electricity can be generated, and sufficient electric energy can be supplied to the load 30 connected to the fuel cell 17.

The fuel electrode 13 and the air electrode 14 are formed with a large number of fine pores 25 (flow passages) (continuous and independent passage holes) having different diameters. Since the fuel electrode 13 and the air electrode 14 have a large number of fine pores 25 formed therein, their specific surface areas are large. The pores 25 have a plurality of through holes 27 that open to the front surface 23 of the fuel electrode 13 and the air electrode 14, and a plurality of through holes 27 that open to the rear surface 24 of the fuel electrode 13 and the air electrode 14. The fuel electrode 13 and the air electrode 14 penetrate through the fuel electrode 13 and the air electrode 14 in the thickness direction from the front surface 23 toward the rear surface 24.

The pores 25 extend between the front surface 23 and the rear surface 24 of the fuel electrode 13 and the air electrode 14 while irregularly bending in the thickness direction of the fuel electrode 13 and the air electrode 14, and at the same time, It extends from the outer peripheral edge 28 of 14 toward the center while being bent in the radial direction of the fuel electrode 13 and the air electrode 14 irregularly. The pores 25 (flow paths) (continuous and independent passage holes) that are adjacent to each other in the radial direction and extend in the thickness direction are partially connected in the radial direction, and one pore 25 and the other pore 25 communicate with each other. is doing. The pores 25 (flow passages) (continuous and independent passage holes) that are adjacent to each other in the thickness direction and extend in the radial direction are partially connected in the thickness direction, and one pore 25 and the other pore 25 communicate with each other. is doing.

The opening area (opening diameter) of the pores 25 (passage holes) is not uniform in the thickness direction, is irregularly changed in the thickness direction, and is not uniform in the radial direction. It changes irregularly in the radial direction. The pores 25 open irregularly in the thickness direction and the radial direction while the opening area (opening diameter) increases or decreases. Further, the opening areas (opening diameters) of the flow opening 27 opening to the front surface 23 of the fuel electrode 13 and the air electrode 14 and the flow opening 27 opening to the rear surface 24 are not uniform, and the areas are all different. is doing. The average diameter (average opening diameter) of the pores 13 (passage holes) and the opening diameter (average opening diameter) of the flow ports 27 of the front and rear surfaces 23, 24 are in the range of 1 μm to 100 μm.

The polymer electrolyte fuel cell 17 is provided with a plurality of pores 25 (continuous and independent passage holes) extending in the fuel electrode 13 and the air electrode 14 used therein while irregularly bending in the thickness direction and the radial direction. Has an average diameter of 1 to 100 μm, a large number of pores 25 are formed per unit volume of the fuel electrode 13 and the air electrode 14, and the specific surface area of the fuel electrode 13 and the air electrode 14 is large. While the gas (gas) flows, the gas (gas) can be brought into wide contact with the contact surfaces of the fuel electrode 13 and the air electrode 14 in the pores 25, and the catalytic activity (catalytic action) of the fuel electrode 13 and the air electrode 14 can be achieved. Can be used effectively and to the maximum extent.

The thickness L1 of the fuel electrode 13 and the air electrode 14 (thin plate electrode 26 having a microporous structure) is in the range of 0.03 mm to 1.5 mm, preferably in the range of 0.05 mm to 1.0 mm. When the thickness dimension L1 of the fuel electrode 13 and the air electrode 14 is less than 0.03 mm (0.05 mm), the strength is lowered, and the fuel electrode 13 and the air electrode 14 are easily damaged or damaged when an impact is applied. , It may not be able to maintain its shape. When the thickness L1 of the fuel electrode 13 and the air electrode 14 exceeds 1.5 mm (1.0 mm), the electric resistance of the fuel electrode 13 and the air electrode 14 increases, and the current flows smoothly to the fuel electrode 13 and the air electrode 14. When the fuel electrode 13 and the air electrode 14 do not flow and are used in the polymer electrolyte fuel cell 17, sufficient electricity cannot be generated in the fuel cell 17, and the load 29 connected to the fuel cell 17 cannot be sufficiently generated. Unable to supply sufficient electrical energy.

In the polymer electrolyte fuel cell 17, since the thickness dimension L1 of the fuel electrode 13 and the air electrode 14 used therein is in the range of 0.03 mm to 1.5 mm, preferably in the range of 0.05 mm to 1.0 mm, The fuel electrode 13 and the air electrode 14 have high strength and can maintain their shapes, and damage or damage of the fuel electrode 13 or the air electrode 14 when the fuel electrode 13 or the air electrode 14 is impacted. Can be prevented. Further, the electric resistance of the fuel electrode 13 and the air electrode 14 can be reduced, and the current smoothly flows through the fuel electrode 13 and the air electrode 14, and the fuel electrode 13 and the air electrode 14 are used for the polymer electrolyte fuel cell 17. When the fuel cell 17 is charged, sufficient electric power can be generated in the fuel cell 17, and sufficient electric energy can be supplied to the load 30 connected to the fuel cell 17.

The porosity of the fuel electrode 13 and the air electrode 14 (the thin plate electrode 26 having a microporous structure) is in the range of 70% to 85%. When the porosities of the fuel electrode 13 and the air electrode 14 are less than 70%, many fine pores 25 (continuous and independent passage holes) are not formed in the fuel electrode 13 and the air electrode 14, and the fuel electrode 13 and the air electrode 14 are not formed. The specific surface area cannot be increased. When the porosity of the fuel electrode 13 and the air electrode 14 exceeds 90%, the opening area (opening diameter) of the pores 25 (continuous and independent passage holes) and the opening area (opening diameter of the flow ports 27 of the front and rear surfaces 23, 24) (opening diameter). ) Becomes unnecessarily large, the strengths of the fuel electrode 13 and the air electrode 14 decrease, and the fuel electrode 13 and the air electrode 14 are easily damaged or damaged when an impact is applied, and their shapes can be maintained. In some cases, the catalytic action of the fuel electrode 13 and the air electrode 14 is lowered, and the catalytic activity cannot be exhibited.

In the polymer electrolyte fuel cell 17, since the porosities of the fuel electrode 13 and the air electrode 14 used therein are within the above range, the fuel electrode 13 and the air electrode 14 have a large number of fine pores having different opening areas (opening diameters). 25 (pores 25 having an average diameter in the range of 1 to 100 μm) and a large number of minute front and rear surfaces 23, 24 having different opening areas (opening diameters) 27, 24 (a passage having an average diameter in the range of 1 to 100 μm) 27), the specific surface area of the fuel electrode 13 and the air electrode 14 can be increased, and the gas (gas) flows through the pores 25 and the gas (gas) is used as a fuel. The contact surfaces of the pores 13 of the electrode 13 and the air electrode 14 can be widely contacted, and the catalytic activity (catalytic action) of the fuel electrode 13 and the air electrode 14 can be effectively and maximally utilized. .. Further, the catalytic action of the fuel electrode 13 and the air electrode 14 is improved, and the excellent catalytic activity of the fuel electrode 13 and the air electrode 14 can be exhibited, and the fuel electrode 13 and the air electrode 14 are the solid polymer fuel cell 17 When it is used, the fuel cell 17 can generate sufficient electricity, and the load 30 connected to the fuel cell 17 can be supplied with sufficient electric energy.

Anode 13 and cathode 14 (thin plate electrode 26 of the micro-porous structure) in the range that the density of ^{6.0g / cm 2 ~8.0g / cm 2} , preferably, 6.5g ^/ cm 2 ~7. It is in the range of 5 g/cm ² . If the densities of the fuel electrode 13 and the air electrode 14 are less than 6.0 g/cm ² (6.5 g/cm ² ), the strength of the fuel electrode 13 and the air electrode 14 will decrease, and the fuel electrode 13 will be affected when an impact is applied. In some cases, the air electrode 14 may be easily broken or damaged and the shape thereof may not be maintained, and the catalytic action of the fuel electrode 13 and the air electrode 14 may be deteriorated and the catalytic activity may not be exhibited. When the densities of the fuel electrode 13 and the air electrode 14 exceed 8.0 g/cm ² (7.5 g/cm ² ), the fuel electrode 13 and the air electrode 14 have many fine pores 25 and many fine flow ports. 27 is not formed, the specific surface area of the fuel electrode 13 and the air electrode 14 cannot be increased, and the catalytic activity (catalytic action) of the fuel electrode 13 and the air electrode 14 cannot be effectively used.

In the polymer electrolyte fuel cell 17, since the densities of the fuel electrode 13 and the air electrode 14 used therein are within the above range, the fuel electrode 13 and the air electrode 14 have many fine pores 25 having different opening areas (opening diameters). The specific surface area of the fuel electrode 13 and the air electrode 14 is formed by forming a porous (microporous structure) having a large number of minute front and rear surfaces 23, 24 through holes 27 having different passage areas and opening areas (opening diameters). Can be increased, and the gas (gas) can widely contact the contact surfaces of the fuel electrode 13 and the air electrode 14 in the flow paths 25 while the gas (gas) flows through the flow paths 25. It is possible to effectively and maximally utilize the catalytic activity (catalytic action) of 13 and the air electrode 14. Furthermore, the catalytic action of the fuel electrode 13 and the air electrode 14 is improved, and the fuel electrode 13 and the air electrode 14 can exhibit excellent catalytic activity.

In the polymer electrolyte fuel cell 17, by setting the density of the fuel electrode 13 and the air electrode 14 used therein to the above range, the fuel electrode 13 and the air electrode 14 have a large number of fine pores having different opening areas (opening diameters). 25 (passage hole) and a large number of minute front and rear surfaces 23, 24 having different opening areas (opening diameters) and formed into a porous (microporous structure) having a flow port 27, the ratio of the fuel electrode 13 and the air electrode 14 The surface area can be increased, and the gas (gas) can be brought into wide contact with the contact surfaces of the fuel electrode 13 and the air electrode 14 in the flow paths 25 while the gas (gas) flows through the flow paths 25. The fuel electrode 13 and the air electrode 14 can surely exhibit substantially the same catalytic activity (catalytic action) as the electrode containing the platinum group metal, and the fuel electrode 13 and the air electrode 14 can be used to generate sufficient electricity. Therefore, sufficient electric energy can be supplied to the load 29 connected to the fuel cell 17.

Fine powder of Pt (Pt processed into powder), Fine powder of Pb (Pb processed into powder), Fine powder of Rh (Rh processed into powder), Fine powder of Ru (in powder form) Processed Ru), Ir fine powder (Ir processed into powder), Os fine powder (Os processed into powder), Ti fine powder (Ti processed into powder), Cr Fine powder (Cr processed into powder), Mn fine powder (Mn processed into powder), Fe fine powder (Fe processed into powder), Co fine powder (processed into powder) Co), Ni fine powder (Ni powder processed), Zn fine powder (Zn powder processed), Nb fine powder (Nb powder processed), Mo fine powder The particle size of (powder-processed Mo), Ag fine powder (powder-processed Ag), and Cu fine powder (powder-processed Cu) is in the range of 1 μm to 100 μm.

If the particle size of the platinum group metal fine powder of the platinum group metal 31 or the transition metal fine powder of the transition metal 32 is less than 1 μm, the pores 25 (passage holes) are blocked by the fine powder of these metals, and the fuel electrode 13 and Many fine pores 25 cannot be formed in the air electrode 14, the specific surface area of the fuel electrode 13 and the air electrode 14 cannot be increased, and the catalytic action of the fuel electrode 13 and the air electrode 14 is reduced. The catalytic activity (catalytic action) of the fuel electrode 13 and the air electrode 14 cannot be effectively used. When the particle size of the platinum group metal fine powder of the platinum group metal 31 or the particle size of the transition metal fine powder of the transition metal 32 exceeds 100 μm, the opening area (opening diameter) of the pores 25 (passage holes) and the front and rear surfaces 23. , 24 has an opening area (opening diameter) larger than necessary, and many fine pores 25 cannot be formed in the fuel electrode 13 and the air electrode 14, and the fuel electrode 13 and the air electrode 14 cannot be formed. In addition to being unable to increase the specific surface area, the catalytic action of the fuel electrode 13 and the air electrode 14 is lowered, and the catalytic activity (catalytic action) of the fuel electrode 13 and the air electrode 14 cannot be effectively utilized.

In the polymer electrolyte fuel cell 17, the particle size of the platinum group metal fine powder of the platinum group metal 31 and the transition metal fine powder of the transition metal 32 forming the fuel electrode 13 and the air electrode 14 is within the above range. The fuel electrode 13 and the air electrode 14 have a large number of fine pores 25 having different opening areas (opening diameters) (pores 25 having an average diameter in the range of 1 to 100 μm) and a large number of fine front and rear portions having different opening areas (opening diameters). The specific surface area of the fuel electrode 13 and the air electrode 14 is increased by being formed into a porous (microporous structure) having the flow ports 27 of the surfaces 23 and 24 (the flow ports 27 having an average diameter in the range of 1 to 100 μm). The gas (gas) can be widely contacted with the contact surfaces of the fuel electrode 13 and the air electrode 14 in the pores 25 while the gas (gas) flows through the pores 25, and the fuel electrode 13 and the air electrode 14 can be widely contacted. The catalytic activity (catalysis) of 14 can be effectively and maximally utilized. Further, the catalytic action of the fuel electrode 13 and the air electrode 14 is improved, and the excellent catalytic activity of the fuel electrode 13 and the air electrode 14 can be exhibited, and the fuel electrode 13 and the air electrode 14 are the solid polymer fuel cell 17 When it is used, the fuel cell 17 can generate sufficient electricity, and the load 30 connected to the fuel cell 17 can be supplied with sufficient electric energy.

Specific examples of the platinum group metal 31 and the transition metal 32 used for the fuel electrode 13 and the air electrode 14 (the thin plate-shaped electrode 26 having a microporous structure) are, as shown in FIG. ) Platinum group metal fine powder 38 (particle size: 1 μm to 100 μm), powdered Ni35 (nickel) transition metal fine powder 39 (particle size: 1 μm to 100 μm), and powdered Fe36 (iron) transition metal fine powder 40 (particle size: 1 μm to 100 μm) is used as a raw material.

The fuel electrode 13 and the air electrode 14 form a fine metal powder mixture 41 in which fine powders 37 to 38 of Pt34, Ni35, and Fe36 and a predetermined binder 33 are uniformly mixed and dispersed, and a pore forming material is added to the fine metal powder mixture 41. 40 (foaming agent) is added, and the metal fine powder mixture 41 to which the pore forming material 40 is added is molded (extrusion molding or injection molding) into a thin plate having a predetermined area to form a metal fine powder molded product 42. By degreasing the body molded product 42 and sintering (baking) it at a predetermined temperature, a microporous structure and a thin plate having a large number of fine pores 25 (pores 25 having an average diameter in the range of 1 to 100 μm) are formed. The electrodes (fuel electrode 13 and air electrode 14) are formed.

In the fuel electrode 13 and the air electrode 14, the metal fine powder mixture 41 of the platinum group metal fine powder 37 of Pt 34 is set so that the combined work function of the work function of Ni 35 and the work function of Fe 36 approximates the work function of the platinum group metal. Of the transition metal fine powder 38 of Ni35 to the total weight of the fine metal powder mixture 41, and the weight ratio of transition metal fine powder 39 of Fe36 to the total weight of the fine metal powder mixture 41 are determined. There is.

The weight ratio of the platinum group metal fine powder 37 of Pt34 (platinum group metal 31) to the total weight (100%) of the metal fine powder mixture 41 is in the range of 4% to 10%, preferably in the range of 5% to 8%. The weight ratio of the transition metal fine powder 38 of Ni35 (transition metal 32) to the total weight (100%) of the metal fine powder mixture 41 is in the range of 45% to 48%. The weight ratio of the transition metal fine powder 39 of Fe36 (transition metal 32) to the total weight (100%) of the metal fine powder mixture 41 is in the range of 45 to 48%.

When the weight ratio of the fine powder 37 of Pt34, the weight ratio of the fine powder 38 of Ni35, and the weight ratio of the fine powder 39 of Fe36 are out of the above ranges, the combined work function of the fine powder 38 of Ni35 and the fine powder 39 of Fe36 becomes The work function of the platinum group metal cannot be approximated, and the fuel electrode 13 and the air electrode 14 made by degreasing and sintering the metal fine powder molded product 42 obtained by molding the metal fine powder mixture 41 carry platinum. It cannot exhibit the same catalytic activity (catalytic action) as the electrode.

In the polymer electrolyte fuel cell 17, the weight ratio of the Pt 34 fine powder 37, the Ni 35 fine powder 38, and the Fe 36 fine powder 39 to the total weight of the metal fine powder mixture 41 is set within the above range. Then, the composite work function of the work functions of the fine powder 38 of Ni35 and the fine powder 39 of Fe36 can be approximated to the work function of the platinum group metal, and the fuel electrode 13 and the air electrode 14 are substantially the same as the electrodes supporting platinum. With the same work function, the fuel electrode 13 and the air electrode 14 have excellent catalytic activity (catalytic action), and the fuel electrode 13 and the air electrode 14 have substantially the same catalytic activity (catalytic action) as the platinum-supported electrode. As a result, the fuel electrode 13 and the air electrode 14 can be used to generate sufficient electricity, and sufficient electric energy can be supplied to the load 30 connected to the fuel cell 17.

FIG. 6 is a diagram for explaining the power generation of the polymer electrolyte fuel cell 10, and FIG. 7 is a diagram showing the results of the electromotive force test of the fuel electrode 13 and the air electrode 14. FIG. 8 is a diagram showing the results of the IV characteristic test of the fuel electrode 13 and the air electrode 14. In the polymer electrolyte fuel cell 10, as shown in FIG. 6, hydrogen (fuel) is supplied to the fuel electrode 13 (electrode) and air (oxygen) is supplied to the air electrode 14 (electrode).

The atmosphere of hydrogen (fuel) supplied to the fuel electrode 13 (relative humidity of fuel) is in the range of 95% to 100% relative humidity, preferably 100%, and the temperature of hydrogen is 45°C to 55°C. Range, preferably in the range of 49°C to 51°C. The hydrogen supplied to the fuel electrode 13 is supplied with steam from a steam generator (not shown) before being supplied to the fuel electrode 13, and its atmosphere (fuel relative humidity) is 95% to 100% ( Preferably, it rises to 100%) and its temperature rises to 45°C to 55°C (preferably 49°C to 51°C).

The supply pressure of hydrogen supplied to the fuel electrode 13 and the supply pressure of air supplied to the air electrode 14 are in the range of +0.06 MPa to +0.08 MPa, preferably +0.07 MPa. In the polymer electrolyte fuel cell 10, an air supply pump (not shown) that pressure-feeds (air supply) hydrogen to be supplied to the fuel electrode 13 and air to be supplied to the air electrode 14 is installed. Is supplied to the air electrode 14 by the air supply pump, and the supply pressure of the air supplied to the air electrode 14 is +0.06 MPa to +0.06 MPa, preferably +0.07 MPa. The pressure is increased to a range of +0.08 MPa, preferably +0.07 MPa.

At the fuel electrode 13 (electrode), hydrogen is decomposed into protons (hydrogen ions, H ⁺ ) and electrons by the reaction (catalytic action) of H ₂ →2H ⁺ +2e ⁻ . After that, protons move to the air electrode 14 through the solid polymer electrolyte membrane 15, and electrons move to the air electrode 14 through the lead wire 29. Protons generated at the fuel electrode 13 flow through the solid polymer electrolyte membrane 15. At the air electrode 14 (electrode), the protons that have moved from the solid polymer electrolyte membrane 15 and the electrons that have moved through the lead wire 29 react with oxygen in the air, and water is produced by the reaction of 4H ⁺ +O ₂ +4e→2H ₂ O. To be done.

The fuel electrode 13 and the air electrode 14 include fine powder of the platinum group metal 31, and further, from the transition metal 32 so that the composite work function of the work functions of the transition metals 32 approximates the work function of the platinum group metal. At least two transition metals 32 are selected, and the total weight of the fine metal powder mixture 43 of the platinum group metal 31 is such that the composite work function of the work functions of the selected transition metals 32 approximates the work function of the platinum group metal. And the weight ratio of the selected transition metal 32 to the total weight of the fine metal powder mixture 43 of the transition metal 32 is determined, the fuel electrode 13 and the air electrode 14 are substantially the same as the platinum-supported electrodes. It has the same work function, exhibits substantially the same catalytic activity (catalytic action) as an electrode supporting platinum, and hydrogen is efficiently decomposed into protons and electrons.

The fuel electrode 13 and the air electrode 14 shown as specific examples include fine particles 37 of Pt34, and Ni35 and Fe36 are selected so that the combined work function of the work functions approximates the work function of the platinum group metal. The weight ratio of the fine powder 37 of Pt34 to the total weight of the fine metal powder mixture 41 is determined so that the total work function of the selected Ni35 and Fe36 work functions approximates the work function of the platinum group metal. Since the weight ratio of the fine powder 38 of Ni35 to the total weight of the fine powder mixture 41 and the weight ratio of the fine powder 39 of Fe36 to the total weight of the metal fine powder mixture 41 are determined, the fuel electrode 13 and the air electrode 14 are It has a work function substantially the same as that of the platinum-supporting electrode, exhibits substantially the same catalytic activity (catalytic action) as the platinum-supporting electrode, and hydrogen is efficiently decomposed into protons and electrons.

In the electromotive voltage test, the voltage (V) between the fuel electrode 13 and the air electrode 14 was measured for 15 minutes after the hydrogen gas was injected. In the diagram showing the results of the electromotive voltage test in FIG. 7, the horizontal axis represents the measurement time (min), and the vertical axis represents the voltage (V) between the fuel electrode 13 and the air electrode 13. In the polymer electrolyte fuel cell 10 using the fuel electrode 13 and the air electrode 14, the voltage between the electrodes was 1.07 (V) to 1.088 (V) as shown in FIG. 7.

In the IV characteristic test, the load 30 was connected between the fuel electrode 13 and the air electrode 14, and the relationship between voltage and current was measured. In the diagram showing the results of the IV characteristic test in FIG. 8, the horizontal axis represents current (A) and the vertical axis represents voltage (V). In the polymer electrolyte fuel cell 10 using the fuel electrode 13 and the air electrode 14, a gradual voltage drop was observed as shown in FIG. As shown in the results of the electromotive force test in FIG. 7 and the results of the IV characteristic test in FIG. 8, the fuel electrode 13 and the air electrode 13 have an excellent catalytic action for promoting the reaction of releasing electrons to become hydrogen ions. In addition, it was confirmed that it has an excellent oxygen reducing function (catalytic action).

In the polymer electrolyte fuel cell 10, the fuel electrode 13 and the air electrode 14 used therein have a composite work function of the work function of the fine powder of the platinum group metal 31 and the predetermined transition metal 32 approximate to the work function of the platinum group metal. A fine metal powder mixture 41 is prepared by uniformly mixing and dispersing at least two types of fine powders of the transition metal 32 selected as described above and a predetermined binder 33 (powder-like resin binder). A predetermined pore forming material 40 (foaming agent) is added (added) to, and the fine metal powder mixture 41 to which the pore forming material 40 is added is molded (extrusion molding or injection molding) into a thin plate shape having a predetermined area. A microporous structure having a large number of fine pores 25 and flow ports 27 is formed by producing a fine metal powder product 42, degreasing and sintering (firing) the fine metal powder product 42 at a predetermined temperature. The thin plate electrode 26, based on the total weight of the fine metal powder mixture 41 of the fine powder of the platinum group metal 31, such that the composite work function of the work functions of the selected transition metals 32 approximates the work function of the platinum group metal. Since the weight ratio is determined and the weight ratio of the fine powder of the selected transition metal 32 to the total weight of the metal fine powder mixture 41 is determined, the fuel electrode 13 and the air electrode 14 are substantially the same as the electrodes supporting platinum. And the fuel electrode 13 and the air electrode 14 have excellent catalytic activity (catalytic action), and the fuel electrode 13 and the air electrode 14 have substantially the same catalytic activity (catalytic action) as the electrode supporting platinum. By exerting the power, the fuel electrode 13 and the air electrode 14 can be used to generate sufficient electricity, and sufficient electric energy can be supplied to the load 30 connected to the fuel cell 10.

Further, a polymer electrolyte fuel cell 10 using a fuel electrode 13 and an air electrode 14 using Pt34 (platinum) as a platinum group metal 31 as a raw material and Ni35 (nickel) and Fe36 (iron) as a transition metal 32 as raw materials. Ni35 and Fe36 are selected so that the composite work function of the transition metal 32 and the work function of the platinum group metal is approximated, and the total work function of the selected Ni35 and Fe36 work functions is the platinum group metal. The weight ratio of the fine powder 37 of Pt 34 to the total weight of the fine metal powder mixture 41 is determined so as to approximate the work function of the fine metal powder mixture 41. Since the weight ratio of the fine powder 39 of Fe36 to the total weight of the body mixture 41 is determined, the fuel electrode 13 and the air electrode 14 have substantially the same work function as the electrode supporting platinum, and the fuel electrode 13 and the air electrode 14 have the same work function. Since the electrode 14 has an excellent catalytic activity (catalytic action), and the fuel electrode 13 and the air electrode 14 exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting platinum, the fuel electrode 13 and the air The poles 14 can be used to generate sufficient electricity to supply the load 30 connected to the fuel cell 10 with sufficient electrical energy.

In the polymer electrolyte fuel cell 10, the fuel electrode 13 and the air electrode 14 include an inexpensive transition metal 32 (for example, Ni35, Fe36) selected from various transition metals 32, and based on the total weight of the fine metal powder mixture 41. The weight ratio of the fine powder of the transition metal 32 (the weight ratio of the fine powder 39 of Ni35, the weight ratio of the fine powder 40 of Fe36) is within the above range, and the fine powder of the platinum group metal 31 relative to the total weight of the metal fine powder mixture 41. Since the weight ratio of the body (the weight ratio of the fine powder 37 of Pt34) is within the above range and the content of the expensive platinum group metal 31 (Pt34) is small, the material cost of the fuel electrode 13 and the air electrode 14 can be reduced. Therefore, the polymer electrolyte fuel cell 10 can be manufactured at low cost, and the operation cost of the polymer electrolyte fuel cell 10 can be reduced.

The polymer electrolyte fuel cell 10 supplies hydrogen (fuel) in an atmosphere having a relative humidity of 95% to 100% to the fuel electrode 13, supplies hydrogen at a temperature of 45° C. to 55° C. to the fuel electrode 13, and outputs +0. By supplying hydrogen to the fuel electrode 13 at a supply pressure of 06 MPa to +0.08 MPa and supplying air (oxygen) to the air electrode 14 at a supply pressure of +0.06 MPa to +0.08 MPa, the fuel electrode 13 and the air electrode 14 are supplied. The catalytic activity of the fuel cell 10 is increased, the electromotive force of the fuel cell 10 is improved, and sufficient electricity can be reliably generated using the non-platinum fuel electrode 13 and the air electrode 14. Sufficient electric energy can be reliably supplied to the load 30.

FIG. 9 is a diagram illustrating a method of manufacturing the fuel electrode 13 and the air electrode 14 used in the polymer electrolyte fuel cell 10. As shown in FIG. 9, the fuel electrode 13 and the air electrode 14 include a metal selection step S1, a metal fine powder preparation step S2, a fine powder weight ratio determination step S3, a metal fine powder mixture preparation step S4, and a metal fine powder molded article preparation. It is manufactured by an electrode manufacturing method including a step S5 and a microporous structure thin plate electrode forming step S6. In the electrode manufacturing method, the platinum group metal 31 and at least two kinds of transition metals 32 are used as raw materials to manufacture the fuel electrode 13 and the air electrode 14 used in the polymer electrolyte fuel cell 10.

In the metal selection step S1, at least one platinum group metal 31 (platinum (Pt), palladium (Pb), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium is selected from among various platinum group metals 31. (Os)) is selected and selected from various transition metals 32. Among the various transition metals 32, the composite work functions of the work functions of at least two types of transition metals 32 are approximated to the work functions of platinum group metals. To at least two kinds of transition metals 32 (Ti (titanium), Cr (chrome), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Nb (Niobium), Mo (molybdenum), Ag (silver)) is selected. Pt34 (platinum) is selected as the platinum group metal 31 used for the fuel electrode 13 and the air electrode 14, and Ni35 (nickel) and Fe36 (iron) are selected as the transition metal 32 used for the fuel electrode 13 and the air electrode 14. It has been done.

In the metal fine powder production step S2, platinum 34 (Pt) is finely pulverized by a fine pulverizer to a particle size of 1 μm to 100 μm, and a platinum group metal fine powder 37 of Pt34 having a particle size of 1 μm to 100 μm is produced. Ni35 (nickel) is finely pulverized to a particle size of 1 μm to 100 μm to form a transition metal fine powder 38 of Ni35 having a particle size of 1 μm to 100 μm, and Fe36 (iron) is particled to a particle size of 1 μm to 100 μm by a fine pulverizer. Then, the transition metal fine powder 39 of Fe36 having a particle size of 1 μm to 100 μm is prepared.

The electrode manufacturing method is to pulverize Pt34 (platinum group metal 31), Ni35 (transition metal 32), and Fe36 (transition metal 32) to a particle size of 1 μm to 100 μm to obtain a large number of fine pores 25 (passage holes). It is possible to form a thin plate-shaped fuel electrode 13 or air electrode 14 having a microporous structure and having a large specific surface area by being formed into a porous structure having a gas. It is possible to make the fuel electrode 13 and the air electrode 14 that can be brought into wide contact with the contact surfaces of the air holes 14 of the air holes 14.

In the fine powder weight ratio determining step S3, the combined work function of the work functions of the fine powder 38 of Ni35 and the fine powder 39 of Fe36 produced in the fine metal powder producing step S2 is approximated to the work function of the platinum group metal. The weight ratio of the Pt34 fine powder 37 to the total weight of the metal fine powder mixture 41 is determined, and the weight ratio of the Ni35 fine powder 38 to the total weight of the metal fine powder mixture 41 is determined. The weight ratio of the fine powder 39 of Fe36 to the total weight is determined.

In the fine powder weight ratio determination step S3, the weight ratio of the fine powder 37 of Pt34 (platinum group metal 31) to the total weight (100%) of the metal fine powder mixture 41 is in the range of 4% to 10%, preferably 5%. Determine in the range of ~8%. In the fine powder weight ratio determining step S3, the weight ratio of the fine powder 38 of Ni35 (transition metal 32) to the total weight (100%) of the metal fine powder mixture 41 is determined within the range of 45% to 48%. The weight ratio of the fine powder 39 of Fe36 (transition metal 32) to the total weight (100%) of the mixture 41 is determined in the range of 45% to 48%.

The electrode manufacturing method selects Ni35 (nickel) and Fe36 (iron) of the transition metal 32 so that the synthetic work function approximates the work function of the platinum group metal, and the synthetic work function is the work function of the platinum group metal. Similarly, the weight ratio of the fine powder 38 of Pt34 to the total weight of the fine metal powder mixture 41, the weight ratio of the fine powder 39 of Ni35 to the total weight of the fine metal powder mixture 41, and the total weight of the fine metal powder mixture 41 are approximated. By determining the weight ratio of the fine powder 39 of Fe36 within the above range, the composite work function of the work functions of the fine powder 38 of Ni35 and the fine powder 39 of Fe36 can be approximated to the work function of the platinum group metal, Despite having a low content of platinum group metal 31 (Pt34), it has a work function substantially the same as that of the platinum-supported electrode and exhibits substantially the same catalytic activity (catalytic action) as the platinum-supported electrode. It is possible to produce the fuel electrode 13 and the air electrode 14 containing a small amount of platinum group metal, which have excellent catalytic activity (catalytic action) and can sufficiently and reliably utilize the catalytic function.

The electrode manufacturing method includes a weight ratio of the fine powder 38 of Ni35 (transition metal 32) to the total weight of the fine metal powder mixture 41 and a weight ratio of fine powder 39 of Fe36 (transition metal 32) to the total weight of the fine metal powder mixture 41. Is in the above range, and the weight ratio of the fine powder 37 of Pt34 (platinum group metal 31) to the total weight of the fine metal powder mixture 41 is in the above range, so that the content of expensive platinum group metal 31 (Pt34) is small. The fuel electrode 13 and the air electrode 14 can be manufactured at low cost.

In the metal fine powder mixture preparing step S4, the fine powder 37 of Pt34 having the weight ratio determined in the fine powder weight ratio determining step S3, and the fine powder 38 of Ni35 and the fine powder weight having the weight ratio determined in the fine powder weight ratio determining step S3. The fine powder 39 of Fe36 and the binder 33 (powder-like resin-based binder) having the weight ratio determined in the ratio determining step S3 are put into a mixer, and the powder of Pt34, the powder of Ni35, and the powder of Fe36 are fed into the mixer. The fine powder 39 of No. 3 and the binder 33 are stirred and mixed, and the fine powder 37 of Pt 34, the fine powder 38 of Ni 35, the fine powder 39 of Fe 36, and the binder 33 are uniformly mixed and dispersed. )make. Next, a predetermined amount of pore forming material 42 (powder blowing agent) is added to the metal fine powder mixture 41. A fine metal powder mixture 41 (foam metal molding material) in which a predetermined amount of pore forming material 42 is put into a mixer or a stirrer, and the fine metal powder mixture 41 is uniformly mixed and dispersed by the mixer or agitator. make. The average diameter and porosity of the pores 25 formed in the fuel electrode 13 and the air electrode 14 are determined by the amount of the pore-forming material 42 (powder blowing agent) added.

In the metal fine powder molded product producing step S5, the metal fine powder mixture 41 (foam metal molding material) produced in the metal fine powder mixture producing step S4 is injected into an injection molding machine (not shown) or an extrusion molding machine (not shown). , And the metal fine powder mixture 41 is injection molded (metal powder injection molding) by an injection molding machine, or the metal fine powder mixture 41 is extruded by an extrusion molding machine (metal powder extrusion molding). Metal fine powder molded product 42 (foamed metal molded product) formed by molding 41 into a thin plate having a predetermined area (thickness dimension L1 is in the range of 0.03 mm to 1.5 mm, preferably 0.05 mm to 1.0 mm). make.

In the microporous structure thin plate electrode producing step S6, the metal fine powder molded article 42 (foamed metal molded article) produced by the metal powder injection molding or the metal powder extrusion molding in the metal fine powder molded article producing step S5 is degreased and degreased. The metal fine powder molded product 42 is put into a firing furnace (combustion furnace, electric furnace, etc.), and the metal fine powder molded product 42 is sintered (fired) at a predetermined temperature for a predetermined time in the firing furnace to obtain a large number of fine pores 25 ( A fuel electrode 13 and an air electrode 14 having a microporous structure and a thin plate shape (thickness dimension L1 is in the range of 0.03 mm to 1.5 mm, preferably in the range of 0.05 mm to 1.0 mm) in which passage holes are formed are formed. ..

The sintering temperature is 900°C to 1400°C. The sintering (firing) time is 2 to 6 hours. In the microporous structure thin plate electrode forming step S6, the pore forming material 40 (powder foaming agent) is formed inside the metal fine powder molded product 42 when the metal fine powder molded product 42 molded into a thin plate having a predetermined area is sintered. After the foaming, the pore-forming material 40 disappears from the inside of the fine metal powder product 42, and a large number of fine pores 25 (flow paths) (continuous and independent passage holes) are formed. The fuel electrode 13 and the air electrode 14 are manufactured.

The electrode manufacturing method is such that the fine powder 37 of Pt 34, the fine powder 38 of Ni 35, and the fine powder 39 of Fe 36 are connected through a binder 40 by metal powder injection molding or metal powder extrusion molding, and metal powder injection molding or metal powder extrusion is performed. The metal fine powder molded product 42 (foamed metal molded product) formed by molding has a predetermined strength, and has a large number of fine pores 25 (passage holes) by sintering the metal fine powder molded product 42. The fuel electrode 13 and the air electrode 14 having a microporous structure and a thin plate shape can be formed, and the shape can be maintained with high strength, and it is possible to prevent breakage or damage when an impact is applied. A non-platinum fuel electrode 13 and an air electrode 14 that are not platinum can be made.

The electrode manufacturing method selects at least one kind of platinum group metal 31 (Pt34) from among various kinds of platinum group metal 31, and selects a work function of at least two kinds of transition metals 32 selected from various kinds of transition metals 32. The metal selection step S1 for selecting at least two kinds of transition metals 32 (for example, Ni35, Fe36) from the various transition metals 32 so that the function approximates the work function of the platinum group metal, and the metal selection step S1. At least one selected platinum group metal 31 (Pt34) is pulverized to form a platinum group metal fine powder (fine powder 37 of Pt34), and at least two transition metals 32 selected in the metal selection step S1 are obtained. A fine metal powder preparation step S2 for finely pulverizing a transition metal fine powder (fine powder 38 of Ni35, fine powder 39 of Fe36) and at least two kinds of transition metal fine powders produced by the fine metal powder preparation step S2. Work function composition so that the work function approximates the work function of the platinum group metal, and the weight ratio of the platinum group metal fine powder (fine powder 37 of Pt34) and at least two kinds of transition metal fine powder (fine powder 38 of Ni35, The fine powder weight ratio determining step S3 for determining the weight ratio of the fine powder 39) of Fe36, and the platinum group metal fine powder (fine powder 37 of Pt34) having the weight ratio determined in the fine powder weight ratio determining step S3 and at least 2 A predetermined binder 33 is added to various kinds of transition metal fine powders (Ni35 fine powder 38, Fe36 fine powder 39), and these are uniformly mixed and dispersed to make a metal fine powder mixture 41 (foam metal molding material). The metal fine powder mixture producing step S4 of adding a predetermined pore forming material 40 to the metal fine powder mixture 41 and the metal fine powder mixture 41 produced by the metal fine powder mixture producing step S4 are formed into a thin plate (metal powder extrusion molding). Or a metal powder injection molding) to form a metal fine powder molded product 42 (foamed metal molded product), and a metal fine powder molded product 42 produced by the metal fine powder molded product manufacturing step S5. A thin plate electrode for a microporous structure for producing a fuel electrode 13 and an air electrode 14 having a microporous structure in which a large number of fine pores 25 are formed by degreasing and sintering the metal fine powder molded product 42 at a predetermined temperature. Since the fuel electrode 13 and the air electrode 14 are manufactured by each of the steps S6 and S6, the thickness dimension L1 is 0.03 mm to 1.5 mm in the steps S1 to S6 (preferably 0.05 mm to 1.0 mm). Range) and a large number of fine pores 25 (passage holes) formed in the fuel electrode 1 3 and the air electrode 14 (thin plate electrode having a microporous structure) can be manufactured, the fuel electrode 13 and the air electrode 14 can be manufactured at a low price, and the catalyst electrode has an excellent catalytic activity (catalytic action). It is possible to produce the fuel electrode 13 and the air electrode 14 containing a small amount of platinum group metal that can sufficiently and surely utilize the above.

The electrode manufacturing method can produce a fuel electrode 13 and an air electrode 14 containing a small amount of platinum group metal, which have excellent catalytic activity (catalyst action) and can sufficiently and surely utilize the catalytic function. The fuel electrode 13 and the air electrode 14 that can be suitably used for the polymer fuel cell 10 can be produced. In the electrode manufacturing method, the fuel electrode 13 and the air electrode 14 produced in steps S1 to S6 exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group metal. And an air electrode containing a small amount of platinum group metal capable of generating sufficient electricity in the fuel cell and supplying sufficient electric energy to the load 30 connected to the polymer electrolyte fuel cell 10. You can make 14.

10 solid polymer fuel cell 11 cell 12 cell stack 13 fuel electrode 14 air electrode 15 solid polymer electrolyte membrane (electrode assembly membrane)
16 Separator 17 Separator 18 Membrane/electrode assembly 19 Gas diffusion layer 20 Gas diffusion layer 21 Gas seal 22 Gas seal 23 Front face 24 Rear face 25 Flow path (continuous and independent passage hole)
26 Thin Metal Electrode 27 Flow Port 28 Outer Edge 29 Conductive Wire 30 Load 31 Platinum Group Metal 32 Transition Metal 33 Binder 34 Pt (Platinum)
35 Ni (nickel)
36 Fe (iron)
37 Pt (platinum) fine powder (platinum group metal fine powder)
38 Ni (nickel) fine powder (transition metal fine powder)
39 Fe (iron) fine powder (transition metal fine powder)
40 Pore forming material (foaming agent)
41 metal fine powder mixture 42 metal fine powder molded product L1 thickness dimension S1 metal selection process S2 metal fine powder preparation process S3 fine powder weight ratio determination process S4 metal fine powder mixture preparation process S5 metal fine powder molded product production process S6 microporous structure Thin plate electrode making process

Claims (11)

A cell stack having a plurality of cells, wherein the cells include a fuel electrode and an air electrode, an electrode assembly film located between the fuel electrode and the air electrode, and an outer side of the fuel electrode and the air electrode. Formed from the separator located on the outside,
The fuel electrode and the air electrode are formed from a small amount of at least one platinum group metal selected from various platinum group metals and at least two transition metal selected from various transition metals,
The fuel electrode and the air electrode are predetermined to be a platinum group metal fine powder obtained by finely pulverizing the selected at least one type of platinum group metal and a transition metal fine powder obtained by finely pulverizing the selected at least two types of transition metals. A predetermined pore-forming material is added to the metal fine powder mixture in which the binder is uniformly mixed and dispersed, and the metal fine-powder mixture to which the pore forming material is added is molded into a thin plate shape having a predetermined area, and the thin plate having the predetermined area. A solid polymer fuel cell, which is a thin plate electrode having a microporous structure in which a large number of fine pores are formed by degreasing and sintering a metal fine powder molded product formed into a shape. In the fuel electrode and the air electrode, at least two kinds of the various transition metals are selected so that the composite work function of the work functions of the selected at least two kinds of transition metals approximates the work function of the platinum group metal. The polymer electrolyte fuel cell according to claim 1, wherein the transition metal is selected. The polymer electrolyte fuel cell according to claim 1 or 2, wherein the pores formed in the fuel electrode and the air electrode have an average diameter in the range of 1 to 100 µm. The polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the thickness dimension of the fuel electrode and the thickness dimension of the air electrode are in the range of 0.03 mm to 1.5 mm. The platinum group metal is Pt (platinum), the transition metal is Ni (nickel) and Fe (iron), and the work function of Ni and the work of Fe at the fuel electrode and the air electrode. And a weight ratio of the platinum group metal fine powder of Pt to the total weight of the metal fine powder mixture and the transition metal fine powder of Ni so as to approximate a work function of the platinum group metal to the work function of the platinum group metal. The solid height according to any one of claims 1 to 4, wherein a weight ratio to the total weight of the fine metal powder mixture and a weight ratio of the transition metal fine powder of Fe to the total weight of the fine metal powder mixture are defined. Molecular fuel cell. The weight ratio of the Pt platinum group metal fine powder to the total weight of the metal fine powder mixture is in the range of 4 to 10%, and the weight ratio of the Ni transition metal fine powder to the total weight of the metal fine powder mixture is The solid polymer fuel cell according to claim 5, wherein the weight ratio of the transition metal fine powder of Fe to the total weight of the fine metal powder mixture is in the range of 45% to 48%, and in the range of 45% to 48%. .. The solid polymer fuel cell according to any one of claims 1 to 6, wherein the porosity of the fuel electrode and the air electrode formed into a thin plate having the microporous structure is in the range of 70% to 85%. .. The micro density of the fuel electrode and the air electrode is molded into a thin plate of a porous structure, according to any one of claims 1 to 7 in the range of 6.0g ^/ cm ² ~8.0g / cm 2 Polymer electrolyte fuel cell. 9. The solid polymer according to claim 1, wherein the particle size of the platinum group metal fine powder of the platinum group metal and the particle size of the transition metal fine powder of the transition metal are in the range of 1 μm to 100 μm. Type fuel cell. In the polymer electrolyte fuel cell, the atmosphere of hydrogen supplied to the fuel electrode is in the range of relative humidity of 95% to 100%, and the temperature of the hydrogen is in the range of 45°C to 55°C. The polymer electrolyte fuel cell according to claim 9. The solid polymer fuel cell according to claim 1, wherein in the solid polymer fuel cell, the supply pressure of hydrogen supplied to the fuel electrode is in the range of +0.06 MPa to +0.08 MPa. ..

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