JP7235284B2 - polymer electrolyte fuel cell - Google Patents

Description

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

A solid polymer electrolyte membrane, an anode electrode and a cathode electrode sandwiching the solid polymer electrolyte membrane from both sides, a fuel container containing a liquid fuel, and a gas-liquid separating porous material provided between the anode electrode and the cathode electrode. and a perforated fixing plate sandwiching the fuel vaporizing layer from both sides. A polymer electrolyte fuel cell with 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 polymer electrolyte fuel cell disclosed in Patent Document 1 is as follows. Catalyst-carrying carbon fine particles are prepared by carrying 55% by weight of platinum fine particles having a particle diameter in the range of 3 to 5 nm on carbon particles, and an appropriate amount of 5% by weight Nafion solution is added to 1 g of the catalyst-carrying carbon fine particles and stirred, Make a catalyst paste for the cathode electrode. After applying the catalyst paste for the cathode electrode on carbon paper as a base material in an amount of 8 mg/cm ² , it is dried to prepare a cathode electrode of 4 cm×4 cm. Next, instead of the platinum fine particles, platinum (Pt)-ruthenium (Ru) alloy fine particles (the ratio of Ru is 60 at%) having a particle diameter in the range of 3 to 5 nm are carried at 55% by weight of the catalyst-carrying carbon fine particles. A suitable amount of 5% by weight Nafion solution is added to 1 g of the catalyst-carrying carbon fine particles and stirred to prepare a catalyst paste for an anode electrode. After applying the catalyst paste for the anode electrode on carbon paper as a base material in an amount of 8 mg/cm ² , it is dried to prepare an anode electrode of 4 cm×4 cm.

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

An object of the present invention is to provide a fuel electrode and an air electrode that can reduce the content of platinum group metals as much as possible and have excellent catalytic activity (catalytic action) despite the low content of platinum group metals. To provide a polymer electrolyte fuel cell capable of generating sufficient electricity using its fuel electrode and air electrode and supplying sufficient electrical energy to a load.

The polymer electrolyte fuel cell of the present invention for solving the above problems comprises a cell stack having a plurality of cells, the cells being electrodes positioned between a fuel electrode and an air electrode, and between the fuel electrode and the air electrode. The fuel electrode and the air electrode are formed from a bonded film and separators positioned outside the fuel electrode and the air electrode, and the fuel electrode and the air electrode are composed of Pt (platinum), Ni (nickel) as a transition metal, and the transition metal. The fuel electrode and the air electrode are composed of finely ground Pt powder, finely ground Ni transition metal powder, and finely ground Fe transition metal powder. A predetermined pore-forming material is added to a metal fine powder mixture in which a body and a predetermined binder are uniformly mixed and dispersed, and the metal fine powder molded product is formed into a thin plate of a predetermined area by degreasing and sintering. is a microporous structure thin plate electrode in which fine pores are formed, and the weight ratio of Pt fine powder to the total weight of the metal fine powder mixture is in the range of 4 to 10%, and Ni transition metal fine powder The weight ratio of the fine metal powder mixture to the total weight of the metal fine powder mixture 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%. be.

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

In 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.

In another example of the polymer electrolyte fuel cell of the present invention, the porosity of the fuel electrode and the air electrode formed into thin plates of microporous structure 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 formed into thin plates of microporous structure is in the range of 6.0 g/cm ² to 8.0 g/cm ² . be.

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

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

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 according to 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. a platinum group metal fine powder formed from at least two types of transition metals, wherein at least one selected platinum group metal is finely ground; a transition metal fine powder is formed by finely grinding at least two selected transition metals; A predetermined pore-forming material is added to the metal fine powder mixture obtained by uniformly mixing and dispersing the binder of No., and the metal fine powder mixture to which the pore-forming material is added is formed into a thin plate having a predetermined area, and then formed into a thin plate having a predetermined area. By degreasing and sintering the molded metal fine powder molding, it is a thin plate electrode with a microporous structure in which a large number of fine pores are formed. The content of group metals can be reduced as much as possible, and sufficient electricity can be generated by using a fuel electrode and an air electrode that utilize the catalytic activity of platinum group metals and the catalytic activity of transition metals. , can supply sufficient electrical energy to the load connected to the fuel cell.

At least two transition metals selected from among various transition metals are added in the anode and the air electrode such that the composite work function of the work functions of the at least two selected transition metals approximates the work function of the platinum group metal. At least two transition metals are selected from various transition metals so that the composite work function of the selected polymer electrolyte fuel cell approximates the work function of the platinum group metal. Although the content of is small, the fuel electrode and the air electrode have substantially the same work function as the platinum-supported electrode, and the fuel electrode and the air electrode have substantially the same catalytic activity as the platinum-supported electrode (catalytic action ), and can generate sufficient electricity using a fuel electrode and an air electrode containing at least two selected transition metals and having excellent catalytic activity, and can be applied to a load connected to the fuel cell. Sufficient electrical energy can be supplied.

In a polymer electrolyte fuel cell in which the average diameter of 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 surfaces of the electrodes can be extensively contacted, and the catalytic action of the anode and cathode can be maximized. A polymer electrolyte fuel cell can generate sufficient electricity by using a fuel electrode and an air electrode having pores with an average diameter of 1 to 100 μm and excellent catalytic activity. enough electrical energy to supply the loaded load.

In a polymer electrolyte fuel cell in which the thickness of the fuel electrode and the thickness of the air electrode are in the range of 0.03 mm to 1.5 mm, the thickness of the fuel electrode and the air electrode are in the above range, so that the fuel electrode Also, the electric resistance of the air electrode can be reduced, and the current can flow smoothly through the fuel electrode and the air electrode. In polymer electrolyte fuel cells, the fuel electrode and the air electrode have substantially the same catalytic activity (catalytic action) as the platinum-supported electrode, and the electrical resistance of the fuel electrode and the air electrode is small. Since the current flows smoothly, sufficient electricity can be generated using the fuel electrode and the air electrode which have excellent catalytic activity and low potential resistance, and sufficient electric energy can be supplied to the load connected to the fuel cell. can supply.

The platinum group metal is Pt (platinum), the transition metals are Ni (nickel) and Fe (iron), and 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, the weight ratio of the transition metal fine powder of Ni to the total weight of the metal fine powder mixture, and the metal fine powder of the transition metal fine powder of Fe In a polymer electrolyte fuel cell for which the weight ratio to the total weight of the fine metal powder mixture is specified, Pt The weight ratio of platinum group metal fine powder, the weight ratio of Ni transition metal fine powder to the total weight of the metal fine powder mixture, and the weight ratio of 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 substantially the same work function as the platinum-supported electrode, 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 approximately the same catalytic activity (catalytic action) as the electrodes, sufficient electricity can be generated using the fuel electrode and air electrode, and sufficient electrical energy can be supplied to the load connected to the fuel cell. can supply. 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, so that the material cost of the fuel electrode and the air electrode can be reduced. Therefore, the polymer electrolyte fuel cell can be manufactured at low cost, and the operating cost of the polymer electrolyte fuel cell can be reduced.

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 weight ratio of the transition metal fine powder of Ni to the total weight of the metal fine powder mixture is in the range of 45% to 48%. A polymer electrolyte fuel cell in which 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%, the composite work function approximates that of the platinum group metal. In addition to selecting Ni (nickel) and Fe (iron), the weight ratio of Pt platinum group metal fine powder to the total weight of the metal fine powder mixture and the weight of Ni transition metal fine powder to the total weight of the metal fine powder mixture By setting the weight ratio of the Fe transition metal fine powder to the total weight of the metal fine powder mixture in the above range, the combined work function of the Ni transition metal fine powder and the Fe transition metal fine powder is the work function of platinum. It is possible to approximate the work function of group metals, and despite the low Pt content, the fuel electrode and air electrode have excellent catalytic activity (catalytic action), and the fuel electrode and air electrode support platinum. By exhibiting approximately the same catalytic activity (catalytic action) as the electrodes, the fuel electrode and air electrode can be used to generate sufficient electricity, and sufficient electrical 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) in the above weight ratio, 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 small, the material cost of the fuel electrode and the air electrode can be reduced, and the polymer electrolyte fuel cell can be manufactured at low cost, and the operating cost of the polymer electrolyte fuel cell can be reduced. can be lowered.

In a polymer electrolyte fuel cell in which the porosity of the fuel electrode and the air electrode formed into a thin plate with a microporous structure is in the range of 70% to 85%, the porosity of the fuel electrode and the air electrode should be within the above range. The fuel electrode and the air electrode are formed into a porous structure having a large number of fine pores (passage holes) (microporous structure with an average pore diameter of 1 to 100 μm), and the specific surface area of the fuel electrode and the air electrode is increased. It is possible to cause the gas to contact the contact surface of the pores of the fuel electrode and the air electrode over a wide range while the gas flows through the pores, and the fuel electrode and the air electrode are almost the same catalyst as the platinum-supported electrode. Sufficient electricity is generated by using fuel electrodes and air electrodes with excellent catalytic activity (catalytic action) that can reliably exhibit activity (catalytic action) and fully and reliably utilize the catalytic function. and can supply sufficient electrical energy to the load connected to the fuel cell.

A polymer electrolyte fuel cell in which the densities of the fuel and air electrodes formed into a thin plate with a microporous structure are in the range of 6.0 g/cm ² to 8.0 g/cm ² have the densities of the fuel and air electrodes. By setting the above range, the fuel electrode and the air electrode are formed into a porous structure having a large number of fine pores (passage holes) (microporous structure with an average pore diameter of 1 to 100 μm), and the ratio of the fuel electrode and the air electrode The surface area can be increased, and while the gas flows through the pores, the gas can be brought into contact with the contact surfaces of the pores of the fuel electrode and the air electrode over a wide range. Using a fuel electrode and an air electrode that can reliably exhibit substantially the same catalytic activity (catalytic action) and can fully and reliably utilize the catalytic function and have excellent catalytic activity (catalytic action) Sufficient electricity can be generated and sufficient electrical 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, By setting 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 pores) (microporous structure with 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 is possible for the gas to contact the contact surface of the pores of the fuel electrode and the air electrode over a wide range while the gas flows through the pores. Excellent catalytic activity (catalytic action) in which the fuel electrode and the air electrode reliably exhibit substantially the same catalytic activity (catalytic action) as the platinum-supported electrode, and the catalytic function can be fully and reliably utilized. Sufficient electricity can be generated using anodes and cathodes having a , sufficient electrical energy to supply a load connected to the fuel cell.

In a polymer electrolyte fuel cell in which the atmosphere of hydrogen supplied to the fuel electrode is in the range of 95% to 100% relative humidity and the temperature of hydrogen is in the range of 45°C to 55°C, the relative humidity is 95% to 100%. By supplying hydrogen to the fuel electrode at a temperature of 45 ° C. to 55 ° C., the catalyst activity of the fuel electrode increases, the electromotive force of the fuel cell improves, and the fuel electrode Sufficient electricity can be reliably generated using the fuel cell and the air electrode, and sufficient electrical energy can be reliably supplied to the load connected to the fuel cell.

In a 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, hydrogen is supplied to the fuel electrode at a supply pressure of +0.06 MPa to +0.08 MPa. , the catalytic activity of the anode is increased, the electromotive force of the fuel cell is enhanced, and sufficient electricity can be reliably generated using the anode and cathode, sufficient for the load connected to the fuel cell. Electric energy can be reliably supplied.

1 is a perspective view of a polymer electrolyte fuel cell shown as an example; FIG. FIG. 2 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 which are shown as an example. FIG. 2 is a partially enlarged front view showing an example of a fuel electrode and an air electrode; FIG. 4 is a diagram for explaining 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. FIG. 4 is a diagram showing results of an IV characteristic test of the fuel electrode and the air electrode; FIG. 4 is a diagram for explaining a method of manufacturing a fuel electrode and an air electrode used in a polymer electrolyte fuel cell;

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

A polymer electrolyte fuel cell 10 includes a cell stack 12 (fuel cell stack) having a plurality of cells 11, and generates electrical energy by supplying hydrogen and oxygen. In the cell stack 12, a plurality of cells 11 (single cells) are stacked in one direction and connected in series. As an example of the cell 11, as shown in FIG. (Electrode assembly membrane) (fluorinated ion exchange membrane having sulfonic acid groups), separator 16 (bipolar plate) located outside the fuel electrode 13 in the thickness direction, and separator 17 located outside the air electrode 14 in the thickness direction (bipolar plate).

The separators 16 and 17 are provided with (engraved) supply channels for reactant gases (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 in the thickness direction and integrated to form a membrane electrode assembly (MEA). , the membrane/electrode assembly 18 is sandwiched between 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. They are in close contact with each other without gaps. The solid polymer electrolyte membrane 15 has proton conductivity and no electronic 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 above and below the gas diffusion layer 20 between the fuel electrode 13 and the separator 16 . Gas seals 22 are installed above and below the gas diffusion layer 20 between the air electrode 14 and the separator 17 .

The fuel electrode 13 (catalyst electrode) and the air electrode 14 (catalyst electrode) used in 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 L1. It has a quadrangular planar shape. 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 (channels) (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 they can be formed into any other planar shape such as a circle or an ellipse in accordance with the application, in addition to the quadrangle.

The fuel electrode 13 and the air electrode 14 (microporous thin plate electrode 26) are made of at least two metals selected from powdered platinum group metal 31 and powdered transition metal 32. It is formed from a transition metal 32 . Platinum (Pt), palladium (Pb), rhodium (Rh), ruthenium (Ru), iridium (Ir), and osmium (Os) can be used as the platinum group metal 31 . At least one of them is used for the platinum group metal 31 . A 3d transition metal or a 4d transition metal is used as the transition metal 32 . Ti (titanium), Cr (chromium), Cu (copper), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), and Zn (zinc) are used as 3d transition metals. Nb (niobium), Mo (molybdenum), and Ag (silver) are used as 4d transition metals. 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 (the energy required to extract electrons from the substance) of the at least two selected transition metals 32 is adjusted to approximate the work function of the platinum group metals. , transition metals 32 are selected. 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), the work function of Nb is 4.01 (eV), the work function of Mo is 4.45 (eV), and the work function of Ag is 4.31 (eV).

The fuel electrode 13 and the air electrode 14 are made of 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 selected from various transition metals 32 Transition metal fine powder of those transition metals 32 (Ti (titanium) processed into fine powder, Cr (chromium) processed into fine powder, Cu (copper) processed into fine powder, Mn (manganese), Fe (iron) processed into fine powder, Co (cobalt) processed into fine powder, Ni (nickel) processed into fine powder, Zn (zinc) processed into fine powder, fine powder Nb (niobium) processed into fine powder, Mo (molybdenum) processed into fine powder, Ag (silver) processed into fine powder) and a predetermined binder 33 (powder resin binder) are uniformly mixed. A metal fine powder mixture 41 is prepared by mixing and dispersing, 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 is spread over a predetermined area. is formed into a thin plate (extrusion molding or injection molding) to make a thin plate-like metal fine powder molding 42, and the metal fine powder molding 42 is degreased and sintered (fired) at a predetermined temperature. (See Figure 9).

In the fuel electrode 13 and the air electrode 14, the metal of the platinum group metal fine powder of the platinum group metal 31 is used so that the composite 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 to the total weight of the fine powder mixture 41 is determined, and the weight ratio of the transition metal fine powder of those transition metals 32 to the total weight of the metal fine powder mixture 41 is determined.

Specifically, the weight ratio of the platinum group metal fine powder of the 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 6% to 8%. and the weight ratio of one type 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%, and the selected transition The weight ratio of the other transition metal fine powder of the metal 32 to the total weight (100%) of the metal fine powder mixture 41 is in the range of 45% to 48%.

Weight ratio of platinum group metal fine powder of platinum group metal 31, weight ratio of transition metal fine powder of one selected transition metal 32, weight of transition metal fine powder of another selected transition metal 32 If the ratio is out of the above range, the synthetic work function of the transition metal fine powder of the transition metals 32 cannot be approximated to the work function of the platinum group metal, and the metal fine powder molding 42 formed by molding the metal fine powder mixture 41 cannot be obtained. The electrode 10 made by degreasing and sintering (firing) cannot exhibit substantially the same catalytic activity (catalytic action) as an electrode supporting platinum.

The polymer electrolyte fuel cell 17 has a weight ratio of the fine powder of the platinum group metal 31 to the total weight of the fine metal powder mixture 41 and the total weight of the fine metal powder mixture 41 of fine powder of the selected one transition metal 32. By setting the weight ratio of the fine powder of the other selected transition metal 32 to the total weight of the metal fine powder mixture 41 in the above range, the work of at least two selected transition metals 32 The composite work function of the function 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 platinum-supported electrode, and the fuel electrode 13 and the air electrode 14 are excellent. The fuel electrode 13 and the air electrode 14 have catalytic activity (catalytic action), and the fuel electrode 13 and the air electrode 14 exhibit substantially the same catalytic activity (catalytic action) as the platinum-supported electrode, so that the fuel electrode 13 and the air electrode 14 can be used. can generate enough electricity to supply sufficient electrical energy to the load 30 connected to the fuel cell 17 .

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

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. It extends from the outer peripheral edge 28 of the fuel electrode 14 toward the center while being irregularly bent in the radial direction of the fuel electrode 13 and the air electrode 14 . The pores 25 (channels) (continuous and independent passage holes) that are adjacent in the radial direction and extend in a curved manner in the thickness direction are partially connected in the radial direction, and the pores 25 on one side and the pores 25 on the other side communicate with each other. are doing. The pores 25 (channels) (continuous and independent passage holes) that are adjacent to each other in the thickness direction and extend in a radial direction are partially connected in the thickness direction, and the pores 25 on one side and the pores 25 on the other side communicate with each other. are doing.

The opening areas (opening diameters) of the pores 25 (passage holes) are not uniform in the thickness direction, but vary irregularly in the thickness direction and are not uniform in the radial direction. It varies irregularly in the radial direction. The pores 25 open irregularly in the thickness direction and the radial direction while their opening areas (opening diameters) increase and decrease. In addition, the opening areas (opening diameters) of the flow holes 27 that open to the front surface 23 and the flow holes 27 that open to the rear surface 24 of the fuel electrode 13 and the air electrode 14 are not uniform, and the areas are all different. are 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 and 24 are in the range of 1 μm to 100 μm.

A polymer electrolyte fuel cell 17 has a plurality of pores 25 (continuous and independent passage pores) formed in the fuel electrode 13 and the air electrode 14 used therein and extending while irregularly bending in the thickness direction and the radial direction. Since the average diameter of is in the range 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) is flowing, the gas (gas) can be brought into contact with the contact surfaces of the pores 25 of the fuel electrode 13 and the air electrode 14 in a wide range, and the catalytic activity (catalysis) of the fuel electrode 13 and the air electrode 14 can be used effectively and to the maximum.

The thickness L1 of the fuel electrode 13 and air electrode 14 (microporous thin plate electrode 26) is in the range of 0.03 mm to 1.5 mm, preferably in the range of 0.05 mm to 1.0 mm. If 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 thereof decreases, and the fuel electrode 13 and the air electrode 14 are easily broken or damaged when an impact is applied. , it may not be able to maintain its shape. When the thickness dimension L1 of the fuel electrode 13 and the air electrode 14 exceeds 1.5 mm (1.0 mm), the electrical resistance of the fuel electrode 13 and the air electrode 14 increases, and the current flows smoothly through the fuel electrode 13 and the air electrode 14. When the fuel electrode 13 and the air electrode 14 are used in the polymer electrolyte fuel cell 17, sufficient electricity cannot be generated in the fuel cell 17 and sufficient electricity is not supplied to the load 29 connected to the fuel cell 17. cannot supply sufficient electrical energy.

Since the thickness dimension L1 of the fuel electrode 13 and the air electrode 14 used in the polymer electrolyte fuel cell 17 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 shape, and the fuel electrode 13 and the air electrode 14 are prevented from being damaged or damaged when an impact is applied to the fuel electrode 13 or the air electrode 14. can be prevented. Furthermore, the electrical resistance of the fuel electrode 13 and the air electrode 14 can be reduced, the current flows smoothly through the fuel electrode 13 and the air electrode 14, and the fuel electrode 13 and the air electrode 14 can be used in the polymer electrolyte fuel cell 17. Sufficient electricity can be generated in the fuel cell 17 when the fuel cell 17 is turned on, and sufficient electrical 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 (microporous thin plate electrode 26) is in the range of 70% to 85%. If the porosity of the fuel electrode 13 and the air electrode 14 is less than 70%, a large number of 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 holes 27 of the front and rear surfaces 23 and 24 ) becomes unnecessarily large, the strength of the fuel electrode 13 and the air electrode 14 is lowered, and the fuel electrode 13 and the air electrode 14 are easily damaged or damaged when an impact is applied, and the shape cannot be maintained. In addition, the catalytic action of the fuel electrode 13 and the air electrode 14 is lowered, and the catalytic activity cannot be exhibited.

Since the porosities of the fuel electrode 13 and the air electrode 14 used in the polymer electrolyte fuel cell 17 are within the above range, the fuel electrode 13 and the air electrode 14 have many fine pores with different opening areas (opening diameters). 25 (pores 25 with an average diameter in the range of 1 to 100 μm) and a large number of flow ports 27 (flow ports with an average diameter in the range of 1 to 100 μm) on the front and rear surfaces 23 and 24 with different opening areas (opening diameters). 27), and the specific surface area of the fuel electrode 13 and the air electrode 14 can be increased. The contact surfaces of the pores 25 of the electrode 13 and the air electrode 14 can be brought into contact in a wide range, and the catalytic activity (catalysis) of the fuel electrode 13 and the air electrode 14 can be effectively and maximized. . 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. can generate sufficient electricity in the fuel cell 17 to supply sufficient electrical energy to the load 30 connected to the fuel cell 17.

The density of the fuel electrode 13 and the air electrode 14 (thin plate electrode 26 with microporous structure) is in the range of 6.0 g/cm ² to 8.0 g/cm ² , preferably 6.5 g/cm ² to 7.0 g/cm 2 . 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 is lowered, and the fuel electrode 13 is damaged when an impact is applied. In some cases, the air electrode 14 is easily damaged or destroyed, and its shape cannot be maintained. When the density of the fuel electrode 13 and the air electrode 14 exceeds 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 openings. 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 (catalysis) of the fuel electrode 13 and the air electrode 14 cannot be effectively utilized.

Since the density of the fuel electrode 13 and the air electrode 14 used in the polymer electrolyte fuel cell 17 is within the above range, the fuel electrode 13 and the air electrode 14 have many fine pores 25 with different opening areas (opening diameters). The specific surface area of the fuel electrode 13 and the air electrode 14 is formed into a porous (microporous structure) having a large number of fine flow openings 27 on the front and rear surfaces 23 and 24 with different opening areas (opening diameters). can be increased, and the gas (gas) can be widely contacted 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 catalytic activity (catalytic action) of 13 and air electrode 14 can be effectively and maximally utilized. 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.

By setting the densities of the fuel electrode 13 and the air electrode 14 used therein in the above range, the polymer electrolyte fuel cell 17 has a large number of fine pores with different opening areas (opening diameters). 25 (passage hole) and a large number of fine flow openings 27 on the front and rear surfaces 23 and 24 with different opening areas (opening diameters). The surface area can be increased, and while the gas (gas) flows through the flow paths 25, the gas (gas) can be brought into contact with the contact surfaces of the flow paths 25 of the fuel electrode 13 and the air electrode 14 over a wide range. , the fuel electrode 13 and the air electrode 14 can reliably exhibit substantially the same catalytic activity (catalytic action) as an electrode containing a platinum group metal, and the fuel electrode 13 and the air electrode 14 can be used to generate sufficient electricity. and can supply sufficient electrical energy to the load 29 connected to the fuel cell 17 .

Pt fine powder (powder processed Pt), Pb fine powder (powder processed Pb), Rh fine powder (powder processed Rh), Ru fine powder (powder processed Ru), fine powder of Ir (Ir processed into powder), fine powder of Os (Os processed into powder), fine powder of Ti (Ti processed into powder), Cr fine powder (Cr processed into powder), fine powder of Mn (Mn processed into powder), fine powder of Fe (Fe processed into powder), fine powder of Co (processed into powder) Co), fine powder of Ni (Ni processed into powder), fine powder of Zn (Zn processed into powder), fine powder of Nb (Nb processed into powder), fine powder of Mo (Mo processed into powder), fine Ag powder (Ag processed into powder), and fine Cu powder (Cu processed into powder) have a particle size 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 A large number of 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 decreases, The catalytic activity (catalytic action) of the fuel electrode 13 and the air electrode 14 cannot be effectively utilized. If 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, the opening area (opening diameter) of the flow opening 27 becomes larger than necessary, and many fine pores 25 cannot be formed in the fuel electrode 13 and the air electrode 14. In addition, 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 used.

In the polymer electrolyte fuel cell 17, the particle size of the fine platinum group metal powder of the platinum group metal 31 and the particle size of the fine transition metal powder of the transition metal 32 forming the fuel electrode 13 and the air electrode 14 are within the above ranges. , the fuel electrode 13 and the air electrode 14 have a large number of fine pores 25 with different opening areas (opening diameters) (pores 25 with an average diameter in the range of 1 to 100 μm) and a large number of fine front and rear pores with different opening areas (opening diameters). The surfaces 23 and 24 are formed into a porous (microporous structure) having flow holes 27 (flow holes 27 with an average diameter in the range of 1 to 100 μm) to increase the specific surface areas of the fuel electrode 13 and the air electrode 14. The gas (gas) flows through the pores 25 and can be brought into contact with the contact surfaces of the pores 25 of the fuel electrode 13 and the air electrode 14 widely. The catalytic activity (catalysis) of 14 can be effectively and maximally utilized. 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. can generate sufficient electricity in the fuel cell 17 to supply sufficient electrical energy to the load 30 connected to the fuel cell 17.

As a specific example of the platinum group metal 31 and the transition metal 32 used for the fuel electrode 13 and the air electrode 14 (microporous thin plate electrode 26), as shown in FIG. 9, powdered Pt 34 (platinum ) of platinum group metal fine powder 38 (particle size: 1 μm to 100 μm), powdered transition metal fine powder 39 of Ni 35 (nickel) (particle size: 1 μm to 100 μm), and powdered powder A transition metal fine powder 40 (particle size: 1 μm to 100 μm) of Fe36 (iron) is used as a raw material.

For the fuel electrode 13 and the air electrode 14, a metal fine powder mixture 41 is prepared by uniformly mixing and dispersing fine powders 37 to 38 of Pt 34, Ni 35, and Fe 36 and a predetermined binder 33, and a pore forming material is added to the metal fine 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 make a metal fine powder molding 42, and the metal fine powder By degreasing the body molding 42 and sintering (firing) it at a predetermined temperature, a microporous structure and a thin plate-like structure in which 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 (anode 13 and cathode 14) are formed.

In the fuel electrode 13 and the air electrode 14, a metal fine powder mixture 41 of platinum group metal fine powder 37 of Pt 34 is added so that the composite 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. , the weight ratio of the transition metal fine powder 38 of Ni35 to the total weight of the metal fine powder mixture 41, and the weight ratio of the transition metal fine powder 39 of Fe36 to the total weight of the metal fine powder mixture 41 were 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%. and the weight ratio of the fine transition metal powder 38 of Ni 35 (transition metal 32) to the total weight (100%) of the fine metal powder mixture 41 is in the range of 45% to 48%. The weight ratio of the transition metal fine powder 39 of Fe 36 (transition metal 32) to the total weight (100%) of the metal fine powder mixture 41 is in the range of 45-48%.

When the weight ratio of the fine powder 37 of Pt 34, the weight ratio of the fine powder 38 of Ni 35, and the weight ratio of the fine powder 39 of Fe 36 are outside the above ranges, the composite work function of the fine powder 38 of Ni 35 and the fine powder 39 of Fe 36 is The work function of the platinum group metal cannot be approximated, and the fuel electrode 13 and the air electrode 14, which are made by degreasing and sintering the metal fine powder molding 42 formed by molding the metal fine powder mixture 41, carry platinum. It cannot exhibit substantially the same catalytic activity (catalytic action) as an electrode.

In the polymer electrolyte fuel cell 17, the weight ratio of the Pt 34 fine powder 37, the weight ratio of the Ni 35 fine powder 38, and the weight ratio of the Fe 36 fine powder 39 to the total weight of the metal fine powder mixture 41 are set within the above ranges. Therefore, 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 platinum-supported electrodes. It has 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. , sufficient electricity can be generated using the fuel electrode 13 and the air electrode 14 , and sufficient electrical 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 an electromotive force test on the fuel electrode 13 and the air electrode 14. As shown in FIG. FIG. 8 is a diagram showing the results of an IV characteristic test of the anode 13 and the cathode 14. In FIG. 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 hydrogen (fuel) atmosphere (relative humidity of the fuel) supplied to the fuel electrode 13 is in the range of 95% to 100% relative humidity, preferably 100%, and the temperature of the hydrogen is 45°C to 55°C. range, preferably between 49°C and 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 the atmosphere (relative humidity of the fuel) is 95% to 100% ( preferably 100%) and the temperature rises to 45° C.-55° C. (preferably 49° C.-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) is installed to pressure-feed hydrogen to be supplied to the fuel electrode 13 and air to be supplied to the air electrode 14. The supply pressure of hydrogen supplied to is in the range of +0.06 MPa to +0.08 MPa, preferably increased to +0.07 MPa, and the supply pressure of air supplied to the air electrode 14 by the air supply pump is +0.06 MPa to It is boosted 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 (catalysis) of H ₂ →2H ⁺ +2e ⁻ . After that, protons move through the solid polymer electrolyte membrane 15 to the air electrode 14 , and electrons move through the conducting wire 29 to the air electrode 14 . Protons generated at the fuel electrode 13 flow through the solid polymer electrolyte membrane 15 . At the air electrode 14 (electrode), the protons transferred from the solid polymer electrolyte membrane 15 and the electrons transferred through the conducting wire 29 react with oxygen in the air, and the reaction of 4H ⁺ +O ₂ +4e→2H ₂ O produces water. be done.

The anode 13 and the cathode 14 include fine powder of a platinum group metal 31, and further, from among the transition metals 32 such that the composite work function of the work function of the transition metals 32 approximates the work function of the platinum group metals. total weight of metal fine powder mixture 43 of platinum group metals 31 wherein at least two transition metals 32 are selected such that the composite work function of the work function of the selected transition metals 32 approximates the work function of the platinum group metals , and the weight ratio of the fine powder of the selected transition metal 32 to the total weight of the fine metal powder mixture 43 is determined. It has the same work function, exhibits almost the same catalytic activity (catalytic action) as the platinum-supported electrode, and efficiently decomposes hydrogen into protons and electrons.

The fuel electrode 13 and air electrode 14 shown as specific examples include fine powder 37 of Pt 34, and Ni 35 and Fe 36 are selected so that the composite work function of the work function approximates that of the platinum group metals. , the weight ratio of the fine powder 37 of Pt 34 to the total weight of the fine metal powder mixture 41 is determined such that the sum of the work functions of the selected Ni 35 and Fe 36 approximates the work function of the platinum group metal; Since the weight ratio of the Ni35 fine powder 38 to the total weight of the fine powder mixture 41 and the weight ratio of the Fe36 fine powder 39 to the total weight of the metal fine powder mixture 41 are determined, the fuel electrode 13 and the air electrode 14 are determined. It has substantially the same work function as the platinum-supported electrode, exhibits substantially the same catalytic activity (catalytic action) as the platinum-supported electrode, and efficiently decomposes hydrogen 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 FIG. 7 showing the results of the electromotive voltage test, 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.

In the IV characteristic test, a load 30 was connected between the fuel electrode 13 and the air electrode 14, and the relationship between voltage and current was measured. In FIG. 8 showing the results of the IV characteristic test, 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 moderate voltage drop was observed as shown in FIG. As shown in the electromotive voltage test results of FIG. 7 and the IV characteristic test results of FIG. It was confirmed that it has an excellent oxygen reduction function (catalytic action).

In the polymer electrolyte fuel cell 10, the fuel electrode 13 and the air electrode 14 used therein are composed of fine powder of the platinum group metal 31 and the work function of the predetermined transition metal 32. The work function is similar to the work function of the platinum group metal. A metal fine powder mixture 41 is prepared by uniformly mixing and dispersing fine powders of at least two kinds of transition metals 32 selected to A predetermined pore-forming material 40 (foaming agent) is added (added), and the metal fine powder mixture 41 to which the pore-forming material 40 is added is molded into a thin plate having a predetermined area (extrusion molding or injection molding) to form a thin plate. A microporous structure having a large number of fine pores 25 and flow openings 27 is produced by making a metal fine powder molding 42, degreasing the metal fine powder molding 42, and sintering (firing) the metal fine powder molding 42 at a predetermined temperature. The thin plate electrode 26, the fine powder of the platinum group metal 31 relative to the total weight of the metal fine powder mixture 41, such that the composite work function of the work function of the selected transition metal 32 approximates the work function of the platinum group metal 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, so that the fuel electrode 13 and the air electrode 14 are substantially the same as the electrode carrying platinum. has a work function of , 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 When the fuel cell 10 is activated, sufficient electricity can be generated using the fuel electrode 13 and the air electrode 14, and sufficient electrical energy can be supplied to the load 30 connected to the fuel cell 10.

In addition, the polymer electrolyte fuel cell 10 uses the fuel electrode 13 and the air electrode 14 using Pt34 (platinum) as the raw material for the platinum group metal 31 and Ni35 (nickel) and Fe36 (iron) as the transition metals 32. Ni35 and Fe36 are selected such that the composite work function of the work function of the transition metal 32 approximates the work function of the platinum group metal, and the sum of the work functions of the selected Ni35 and Fe36 is the platinum group metal The weight ratio of Pt34 fine powder 37 to the total weight of the metal fine powder mixture 41 is determined so as to approximate the work function of Since the weight ratio of the Fe 36 fine powder 39 to the total weight of the solid mixture 41 is determined, the fuel electrode 13 and the air electrode 14 have substantially the same work function as the platinum-supported electrode, and the fuel electrode 13 and the air The electrode 14 has 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 platinum-supported electrode, so that the fuel electrode 13 and the air Sufficient electricity can be generated using the poles 14 to supply sufficient electrical energy to the load 30 connected to the fuel cell 10 .

In the polymer electrolyte fuel cell 10, the fuel electrode 13 and the air electrode 14 contain inexpensive transition metals 32 (eg, Ni35, Fe36) selected from various transition metals 32, and the total weight of the metal fine powder mixture 41 is The weight ratio of the fine powder of the transition metal 32 (the weight ratio of the fine powder 39 of Ni 35 and the weight ratio of the fine powder 40 of Fe 36) is within the above range, and the fine powder of the platinum group metal 31 with respect to the total weight of the fine metal powder mixture 41 The material cost of the fuel electrode 13 and the air electrode 14 can be reduced because the weight ratio of the solid (weight ratio of the fine powder 37 of Pt 34) is within the above range and the content of the expensive platinum group metal 31 (Pt 34) is small. Therefore, the polymer electrolyte fuel cell 10 can be manufactured at low cost, and the operating cost of the polymer electrolyte fuel cell 10 can be reduced.

The polymer electrolyte fuel cell 10 supplies hydrogen (fuel) in an atmosphere with 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 supplies +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 increases the catalytic activity of the fuel cell 10, improves the electromotive force of the fuel cell 10, can reliably generate sufficient electricity using the non-platinum fuel electrode 13 and the air electrode 14, and is connected to the fuel cell 10 Sufficient electrical 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. As shown in FIG. 9, the fuel electrode 13 and the air electrode 14 are subjected to a metal selection step S1, a fine metal powder preparation step S2, a fine powder weight ratio determination step S3, a fine metal powder mixture preparation step S4, and a fine metal powder molding preparation step S4. It is manufactured by an electrode manufacturing method having step S5 and microporous structure thin plate electrode manufacturing step S6. In the electrode manufacturing method, a 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 (Os)), and among the various transition metals 32 such that the composite work function of the work functions of at least two transition metals 32 selected from the various transition metals 32 approximates the work function of the platinum group metals. at least two transition metals 32 (Ti (titanium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Nb (niobium), Mo (molybdenum), Ag (silver)). 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. shall have been

In the metal fine powder preparation step S2, platinum 34 (Pt) is finely pulverized to a particle size of 1 μm to 100 μm by a fine pulverizer to produce platinum group metal fine powder 37 of Pt 34 having a particle size of 1 μm to 100 μm. Ni35 (nickel) is finely pulverized to a particle size of 1 μm to 100 μm by using a fine pulverizer to make transition metal fine powder 38 of Ni35 with a particle size of 1 μm to 100 μm. , to make Fe36 transition metal fine powder 39 with a particle size of 1 μm to 100 μm.

In the electrode manufacturing method, Pt 34 (platinum group metal 31), Ni 35 (transition metal 32), and Fe 36 (transition metal 32) are pulverized to a particle size of 1 μm to 100 μm to form a large number of fine pores 25 (passage holes). It is possible to make the fuel electrode 13 and the air electrode 14 having a microporous structure and a thin plate shape with a large specific surface area, and the gas (gas) flows through the pores 25 while the gas is passed through the fuel electrode 13 and the air electrode 14. It is possible to make the anode 13 and the cathode 14 capable of extensively contacting the contact surfaces of the pores 25 of the cathode 14 .

In the fine powder weight ratio determining step S3, the composite work function of the work functions of the Ni35 fine powder 38 and the Fe36 fine powder 39 produced in the metal fine powder producing step S2 is adjusted so as to approximate the work function of 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, the weight ratio of the fine powder 38 of Ni 35 to the total weight of the fine metal powder mixture 41 is determined, and the weight ratio of the fine metal powder mixture 41 is determined. Determine the weight ratio of Fe36 fine powder 39 to the total weight.

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 fine metal powder mixture 41 is set in the range of 4% to 10%, preferably 5%. Determined in the range of ~8%. In the fine powder weight ratio determination step S3, the weight ratio of the fine powder 38 of Ni35 (transition metal 32) to the total weight (100%) of the fine metal powder mixture 41 is determined in the range of 45% to 48%, and the fine metal powder 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%.

In the electrode manufacturing method, Ni35 (nickel) and Fe36 (iron) of the transition metal 32 are selected so that the composite work function approximates the work function of the platinum group metal, and the composite work function is similar to that of the platinum group metal. As an approximation, the weight ratio of the Pt34 fine powder 38 to the total weight of the metal fine powder mixture 41, the weight ratio of the Ni35 fine powder 39 to the total weight of the metal fine powder mixture 41, and the weight ratio of the Ni35 fine powder 39 to the total weight of the metal fine powder mixture 41 By determining the weight ratio of the Fe36 fine powder 39 in the above range, the composite work function of the work functions of the Ni35 fine powder 38 and the Fe36 fine powder 39 can be approximated to the work function of the platinum group metal, Although the content of the platinum group metal 31 (Pt34) is small, it has substantially the same work function as 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 fully and reliably utilize the catalytic function.

In the electrode manufacturing method, the weight ratio of Ni35 (transition metal 32) fine powder 38 to the total weight of metal fine powder mixture 41 and the weight ratio of Fe36 (transition metal 32) fine powder 39 to the total weight of metal fine powder mixture 41 are determined. is within the above range, and the weight ratio of the fine powder 37 of Pt34 (platinum group metal 31) to the total weight of the metal fine powder mixture 41 is within the above range, so the content of the 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 preparation 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 having the weight ratio determined in the fine powder weight ratio determining step S3 and the fine powder weight. The Fe36 fine powder 39 and the binder 33 (powder resin binder) having the weight ratio determined in the ratio determination step S3 are put into a mixer, and the mixer is used to mix Pt34 fine powder 37, Ni35 fine powder 38, and Fe36. Fine powder 39 of Pt 34, fine powder 38 of Ni 35, fine powder 39 of Fe 36, fine powder 39 of Fe 36, and fine metal powder mixture 41 in which binder 33 is uniformly mixed and dispersed (metal foam molding material )make. Next, a predetermined amount of pore forming material 42 (powder foaming agent) is added to the metal fine powder mixture 41 . A metal fine powder mixture 41 (foamed metal molding material) is obtained by putting a predetermined amount of pore forming material 42 into a mixer or stirrer, and uniformly mixing and dispersing the pore forming material 42 in the metal fine powder mixture 41 by the mixer or stirrer. 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 addition amount of the pore forming material 42 (powder foaming agent).

In the metal fine powder molding production process S5, the metal fine powder mixture 41 (foamed metal molding material) produced in the metal fine powder mixture production process S4 is injected into an injection molding machine (not shown) or an extrusion molding machine (not shown). Then, 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 extruder (metal powder extrusion molding), and the metal fine powder mixture Metal fine powder molding 42 (foamed metal molding) obtained 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 in the range of 0.05 mm to 1.0 mm). make.

In the microporous structure thin plate electrode producing step S6, the metal fine powder molding 42 (foamed metal molding) produced by metal powder injection molding or metal powder extrusion molding in the metal fine powder molding producing step S5 is degreased and degreased. The metal fine powder molding 42 is put into a firing furnace (combustion furnace, electric furnace, etc.), and the metal fine powder molding 42 is sintered (fired) in the firing furnace at a predetermined temperature for a predetermined time to form 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 0.05 mm to 1.0 mm) with passage holes are formed. .

The sintering temperature is between 900°C and 1400°C. The sintering (firing) time is 2 to 6 hours. In the microporous structure thin plate electrode preparation step S6, during the sintering of the fine metal powder molding 42 formed into a thin plate having a predetermined area, the pore forming material 40 (powder foaming agent) is added inside the fine metal powder molding 42. After foaming, the pore forming material 40 disappears from the inside of the metal fine powder molding 42, and a microporous structure and thin plate-like structure in which a large number of fine pores 25 (channels) (continuous and independent passage holes) are formed is formed. Anode 13 and cathode 14 are manufactured.

In the electrode manufacturing method, Pt 34 fine powder 37, Ni 35 fine powder 38, and Fe 36 fine powder 39 are connected via a binder 40 by metal powder injection molding or metal powder extrusion molding. The metal fine powder molding 42 (foam metal molding) produced by molding has a predetermined strength, and by sintering the metal fine powder molding 42, it has a large number of fine pores 25 (passage holes). The fuel electrode 13 and the air electrode 14 having a microporous structure and a thin plate shape can be produced, and the shape can be maintained with high strength, and breakage and damage when impact is applied can be prevented. Non-platinum anodes 13 and cathodes 14 can be made.

In the electrode manufacturing method, at least one platinum group metal 31 (Pt34) is selected from various platinum group metals 31, and at least two types of transition metals 32 selected from various transition metals 32 are combined. By a metal selection step S1 of selecting at least two transition metals 32 (for example, Ni35, Fe36) from various transition metals 32 such that the function approximates the work function of a platinum group metal, and a metal selection step S1 At least one selected platinum group metal 31 (Pt34) is pulverized to produce platinum group metal fine powder (fine powder 37 of Pt34), and at least two transition metals 32 selected by a metal selection step S1 are A metal fine powder preparation step S2 for pulverizing to make transition metal fine powders (Ni35 fine powder 38, Fe36 fine powder 39), and at least two kinds of transition metal fine powders prepared by the metal fine powder preparation step S2. The weight ratio of the platinum group metal fine powder (Pt34 fine powder 37) and at least two transition metal fine powders (Ni35 fine powder 38, a fine powder weight ratio determining step S3 for determining the weight ratio of the fine powder 39) of Fe36; A predetermined binder 33 is added to various types of transition metal fine powder (Ni35 fine powder 38, Fe36 fine powder 39), and they are uniformly mixed and dispersed to prepare a metal fine powder mixture 41 (foam metal molding material), A metal fine powder mixture preparation step S4 of adding a predetermined pore forming material 40 to the metal fine powder mixture 41, and the metal fine powder mixture 41 prepared by the metal fine powder mixture preparation step S4 is formed into a thin plate (metal powder extrusion molding). or metal powder injection molding) to form a metal fine powder molded article 42 (foamed metal molded article), and the metal fine powder molded article 42 produced by the metal fine powder molded article preparing step S5. is degreased and the metal fine powder molding 42 is sintered at a predetermined temperature to produce a microporous structure thin plate fuel electrode 13 and air electrode 14 having a large number of fine pores 25 formed therein. Since the fuel electrode 13 and the air electrode 14 are manufactured by each step including step S6, the thickness dimension L1 is in the range of 0.03 mm to 1.5 mm (preferably 0.05 mm to 1.0 mm) by these steps S1 to S6. range) and a large number of fine pores 25 (passage holes) are formed in the fuel electrode 1 3 and the air electrode 14 (microporous structure thin plate electrode) can be manufactured, the fuel electrode 13 and the air electrode 14 can be manufactured at low cost, and it has excellent catalytic activity (catalytic action) and has a catalytic function. It is possible to make the fuel electrode 13 and the air electrode 14 containing a small amount of platinum group metal that can fully and reliably utilize the.

The electrode manufacturing method can produce the fuel electrode 13 and the air electrode 14 containing a small amount of platinum group metals that have excellent catalytic activity (catalytic action) and can fully and reliably utilize the catalytic function. The fuel electrode 13 and the air electrode 14 that can be suitably used in the polymer fuel cell 10 can be made. In the electrode manufacturing method, the fuel electrode 13 and the air electrode 14 manufactured by steps S1 to S6 exhibit substantially the same catalytic activity (catalytic action) as the electrode supporting the platinum group metal, so the polymer electrolyte fuel cell 10 A fuel electrode 13 containing little platinum group metal and an air electrode capable of generating sufficient electricity at and supplying sufficient electrical energy to the load 30 connected to the polymer electrolyte fuel cell 10 14 can be made.

REFERENCE SIGNS LIST 10 polymer electrolyte 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 surface 24 Rear surface 25 Flow path (continuous and independent passage holes)
26 Thin plate metal electrode 27 Flow port 28 Peripheral edge 29 Lead 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 former (foaming agent)
41 Fine metal powder mixture 42 Fine metal powder molding L1 Thickness dimension S1 Metal selection step S2 Fine metal powder preparation step S3 Fine powder weight ratio determination step S4 Fine metal powder mixture preparation step S5 Fine metal powder molding preparation step S6 Microporous structure Thin plate electrode making process

Claims (8)

a cell stack having a plurality of cells, the cells comprising an anode and a cathode; an electrode assembly membrane positioned between the anode and the cathode; formed from a separator located on the outside and
The fuel electrode and the air electrode are formed of Pt (platinum), Ni (nickel) as a transition metal, and Fe (iron) as a transition metal,
The fuel electrode and the air electrode are composed of the Pt fine powder obtained by finely pulverizing the Pt, the transition metal fine powder of Ni obtained by finely pulverizing the Ni, and the transition metal fine powder of Fe obtained by finely pulverizing the Fe. A predetermined pore-forming material is added to a fine metal powder mixture obtained by uniformly mixing and dispersing a A thin plate electrode with a microporous structure in which pores are formed,
The weight ratio of the Pt 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 45% to 45%. A polymer electrolyte fuel cell, wherein a 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%. 2. The polymer electrolyte fuel cell according to claim 1, wherein the average diameter of pores formed in said fuel electrode and said air electrode is in the range of 1 to 100 μm. 3. The polymer electrolyte fuel cell according to claim 1, 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. 4. The polymer electrolyte fuel cell according to claim 1, wherein said fuel electrode and said air electrode formed into thin plates of microporous structure have a porosity in the range of 70% to 85%. . 5. The method according to any one of claims 1 to 4, wherein the density of the fuel electrode and the air electrode formed into the microporous thin plate is in the range of 6.0 g/cm ² to 8.0 g/cm ² . Polymer electrolyte fuel cell. 6. The solid polymer according to any one of claims 1 to 5, 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. shaped fuel cell.


In the polymer electrolyte fuel cell, the atmosphere of hydrogen supplied to the fuel electrode has a relative humidity of 95% to 100%, and the temperature of the hydrogen is in the range of 45°C to 55°C. 7. The polymer electrolyte fuel cell according to claim 6. 8. The polymer electrolyte fuel cell according to claim 1, wherein the supply pressure of hydrogen supplied to the fuel electrode is in the range of +0.06 MPa to +0.08 MPa. .

Images