JP2007035527A - Collector and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate low-cost manufacture of a collector composed of a porous material having a locally varying aperture ratio by fabricating the collector by bonding a plurality of members having different aperture ratios, to prevent the occurrence of flooding in a gas flow path in a fuel cell, and to enhance power generation efficiency, cooling capability, and output power of the fuel cell. <P>SOLUTION: The collector of a separator unit 12 is sandwiched between fuel cells each having an electrolyte layer sandwiched between a fuel electrode and an oxygen electrode. The collector comprises: a separator contact section contacting a plate-shaped separator main body 41 that shields a gas supplied to the fuel electrode and a gas supplied to the oxygen electrode from each other; an electrode contact section contacting the fuel electrode or the oxygen electrode; and a rib section connecting the separator contact section and the electrode contact section to each other. The collector is fabricated by bonding a plurality of members having different aperture ratios. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a current collector and a method for manufacturing the current collector.

  Conventionally, since fuel cells have high power generation efficiency and do not emit harmful substances, they have been put to practical use as power generators for industrial and household use, or as power sources for artificial satellites and spacecrafts. Development is progressing as a power source for vehicles such as passenger cars, buses and trucks. The fuel cell may be of an alkaline aqueous solution type, a phosphoric acid type, a molten carbonate type, a solid oxide type, a direct type methanol or the like, but has a low reaction temperature and is advantageous for miniaturization. Molecular fuel cells are common.

  In this case, a MEA (Membrane Electrode Assembly) in which a solid polymer electrolyte membrane is sandwiched between two gas diffusion electrodes and joined together is used. When one of the gas diffusion electrodes is used as a fuel electrode (anode electrode) and hydrogen gas as a fuel is supplied to the surface of the gas diffusion electrode, hydrogen is decomposed into hydrogen ions (protons) and electrons, and the hydrogen ions are converted into a solid polymer electrolyte. Permeates the membrane. Further, when the other of the gas diffusion electrodes is an oxygen electrode (cathode electrode) and air as an oxidant is supplied to the surface, oxygen in the air is combined with the hydrogen ions and electrons to generate water. The An electromotive force is generated by such an electrochemical reaction.

  The polymer electrolyte fuel cell has a laminated structure in which a separator that forms a supply passage for a reactive gas such as hydrogen gas as a fuel gas or an oxidant gas such as oxygen is provided outside the MEA. The separator prevents current gas from passing through the MEAs adjacent to each other in the stacking direction, and collects current to extract the generated current to the outside. In this way, a fuel cell stack is configured by laminating a large number of unit cells composed of MEAs and separators.

By the way, in the fuel cell system, an amount of heat corresponding to the generated power is generated in each cell due to the electrochemical reaction. In particular, in a polymer electrolyte fuel cell operating at a low temperature, each cell is heated excessively. It is provided with a cooling means for preventing the increase (for example, see Patent Documents 1 and 2).
JP-A-8-306371 JP 10-340734 A

  However, in the conventional fuel cell system, a temperature distribution may occur in the stacking direction of the unit cells, and the electrode temperature may increase. In this case, the amount of moisture dissipated to the outside of the MEA through the electrode is excessively increased, and the humidity inside the MEA is lowered, so that the power generation efficiency in each unit cell is lowered. Thus, a technique has been proposed that uses a current collector made of a porous body whose aperture ratio is locally changed. However, it is difficult to manufacture a current collector made of a porous body whose aperture ratio is locally changed, which increases the manufacturing cost.

  The present invention solves the above-mentioned conventional problems, and manufactures a current collector by joining a plurality of members having different aperture ratios, whereby a current collector made of a porous body whose aperture ratio is locally changed. Can be easily manufactured at low cost, no flooding occurs in the gas flow path in the fuel cell, power generation efficiency is high, cooling capacity is high, and the output of the fuel cell can be increased. It is an object of the present invention to provide an electric body and a manufacturing method thereof.

  Therefore, the current collector of the present invention is a current collector of a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode, and the gas supplied to the fuel electrode and the oxygen A separator abutting portion that abuts on a plate-shaped separator body that blocks gas supplied to the electrode, an electrode abutting portion that abuts on the fuel electrode or the oxygen electrode, and the separator abutting portion and the electrode abutting portion. And a plurality of members having different opening ratios.

  In another current collector of the present invention, the electrode contact portion is made of a member having a larger opening ratio than members of the separator contact portion and the rib portion.

  In still another current collector of the present invention, the separator contact portion and the rib portion are made of a member obtained by removing a trough portion of a corrugated porous plate having a first aperture ratio, and the electrode contact portion The member is a flat plate having a second opening ratio larger than the first opening ratio, and is a member joined to the corrugated plate so as to close the removed valley Consists of.

  In still another current collector of the present invention, the first aperture ratio is zero.

  In still another current collector of the present invention, the electrode contact portion is composed of a flat plate-like porous plate having a predetermined aperture ratio, and the separator contact portion and the rib portion are made of the flat plate-like porous plate. It consists of a linear body without an opening joined to one surface.

  The current collector manufacturing method of the present invention is a method of manufacturing a current collector for a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode, and includes a wave having a first aperture ratio. A trough portion in a predetermined range of the plate-like perforated plate is deleted, and the flat perforated plate corresponding to the predetermined range is provided with a second aperture ratio larger than the first aperture ratio so as to block the deleted trough portion. To the corrugated porous plate.

  In another method for producing a current collector of the present invention, the flat plate-like porous plate is further joined to the corrugated plate-like porous plate by diffusion bonding.

  In yet another method of manufacturing a current collector of the present invention, a method of manufacturing a current collector of a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode, wherein a predetermined aperture ratio is set. A linear body having no opening is bonded to one surface of the flat plate-like porous plate.

  In still another method of manufacturing a current collector according to the present invention, the linear body is further joined to a flat porous plate by diffusion joining.

  In still another method for producing a current collector of the present invention, a plurality of the linear bodies are arranged in parallel.

  According to the present invention, the current collector is a current collector of a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode, and the gas supplied to the fuel electrode and the oxygen A separator abutting portion that abuts on a plate-shaped separator body that blocks gas supplied to the electrode, an electrode abutting portion that abuts on the fuel electrode or the oxygen electrode, and the separator abutting portion and the electrode abutting portion. And a plurality of members having different opening ratios.

  In this case, it is possible to obtain a current collector made of a porous body whose aperture ratio is locally changed. And the temperature distribution in a fuel cell stack can be eliminated, and the temperature of a fuel cell can be controlled appropriately. Therefore, the humidity in the fuel cell can be properly maintained, and the power generation efficiency can be improved. Further, the cooling capacity can be improved and the output of the fuel cell can be increased.

  According to the present invention, there is provided a method for manufacturing a current collector, wherein the current collector is a method for manufacturing a current collector of a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode. A trough portion in a predetermined range of a corrugated porous plate having an aperture ratio is deleted, a flat aperture plate having a second aperture ratio larger than the first aperture ratio and corresponding to the predetermined range is deleted It joins to the said corrugated sheet porous plate so that a trough part may be plugged up.

  In this case, a current collector made of a porous body whose aperture ratio is locally changed can be easily manufactured at a low cost.

  Furthermore, according to the present invention, in another method of manufacturing a current collector, a method of manufacturing a current collector for a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode, A linear body that does not have an opening is joined to one surface of a flat plate-like perforated plate that has an opening ratio of.

  In this case, a current collector made of a porous body whose aperture ratio is locally changed can be easily manufactured at a low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 2 is a diagram showing the configuration of the fuel cell system according to the first embodiment of the present invention, FIG. 3 is a diagram showing the configuration of the control system for the fuel cell system according to the first embodiment of the present invention, and FIG. It is a figure which shows the structure of the fuel cell stack in the 1st Embodiment of this invention.

  2 and 4, reference numeral 20 denotes a fuel cell stack as a fuel cell (FC), which is used as a power source for vehicles such as passenger cars, buses, trucks, passenger carts, and luggage carts. Here, the vehicle includes a large number of auxiliary devices that consume electricity, such as a lighting device, a radio, and a power window, which are used even when the vehicle is stopped. Since the required output range is extremely wide, it is desirable to use a fuel cell stack 20 as a power source in combination with a secondary battery as a power storage means (not shown).

  The fuel cell stack 20 is of an alkaline aqueous solution type (AFC), phosphoric acid type (PAFC), molten carbonate type (MCFC), solid oxide type (SOFC), direct methanol (DMFC), or the like. However, a polymer electrolyte fuel cell (PEMFC) is desirable.

  More preferably, it is called a PEMFC (Proton Exchange Membrane Fuel Cell) type fuel cell or PEM (Proton Exchange Membrane) type fuel cell using hydrogen gas as fuel and oxygen or air as oxidant. Here, the PEM type fuel cell is generally a stack in which a plurality of cells (Fuel Cell) in which a catalyst, an electrode and a separator are combined on both sides of a solid polymer electrolyte membrane that transmits ions such as protons are connected in series. (Stack).

  In the present embodiment, the fuel cell stack 20 includes a plurality of cell modules 10 as shown in FIG. Note that the arrows in FIG. 4 indicate the flow of refrigerant in a closed cooling system that is one of a plurality of cooling systems for cooling the fuel cell stack 20. The cell module 10 is a unit cell (MEA) 11 to be described later as a fuel cell, electrically connects the unit cells 11 to each other, and the flow path of hydrogen gas introduced into the unit cell 11 and air Thickness direction (diagonal direction connecting the lower left corner and the upper right corner in FIG. 4) as a set of a separator unit 12 to be described later for separating the flow path and a frame (not shown) that supports the unit cell 11 and the separator unit 12. A plurality of sets are stacked on top of each other.

  FIG. 2 shows an apparatus for supplying hydrogen gas as fuel gas and air as oxidant to the fuel cell stack 20. Although hydrogen gas, which is fuel taken out by reforming methanol, gasoline, or the like by a reformer (not shown), can be directly supplied to the fuel cell stack 20, it is stable and sufficient even during high-load operation of the vehicle. In order to be able to supply an amount of hydrogen gas, it is desirable to supply the hydrogen gas stored in the fuel storage means 73. Thereby, the hydrogen gas is always sufficiently supplied at a substantially constant pressure, so that the fuel cell stack 20 can follow the fluctuation of the load of the vehicle and supply a necessary current. . In this case, the output impedance of the fuel cell stack 20 is extremely low and can be approximated to zero.

  Hydrogen gas is stored in a container containing a hydrogen storage alloy, a container containing a hydrogen storage liquid such as decalin, a fuel storage means 73 such as a hydrogen gas cylinder, a first fuel supply line 21 as a fuel supply line, and The fuel is supplied to the fuel chamber of the fuel cell stack 20 through a second fuel supply line 33 as a fuel supply line connected to the first fuel supply line 21. The first fuel supply line 21 is provided with a fuel storage means on-off valve 24, hydrogen pressure sensors 27 and 28 as pressure sensors for detecting the pressure of hydrogen gas, and a first pressure for adjusting the pressure of supplied hydrogen gas. One hydrogen supply pressure regulating valve 25a, a second hydrogen supply pressure regulating valve 25b, and a fuel supply electromagnetic valve 26 are disposed.

  Here, the fuel storage means 73 has a sufficiently large capacity and is capable of always supplying a sufficiently high pressure of hydrogen gas. In the example shown in FIG. 2, a plurality of, for example, three fuel storage means 73 are provided, and a plurality of first fuel supply pipes 21 are connected to each fuel storage means 73. It is branched and is merged on the way to become one. However, the number of the fuel storage means 73 may be singular, plural, or any number in the case of plural.

  The hydrogen gas discharged from the fuel chamber of the fuel cell stack 20 is discharged to the outside of the fuel cell stack 20 through the fuel discharge pipe 31. A water recovery drain tank 60 as a recovery container is disposed in the fuel discharge line 31. The water recovery drain tank 60 is connected to a fuel discharge line 30 for discharging water and separated hydrogen gas. The fuel discharge line 30 is provided with a suction circulation pump 36 as a fuel forced discharge device. It is installed. The end of the fuel discharge line 30 opposite to the water recovery drain tank 60 is connected to the second fuel supply line 33. Thereby, the hydrogen gas led out of the fuel cell stack 20 can be recovered, supplied to the fuel chamber of the fuel cell stack 20, and reused.

  Further, a fuel discharge line 56 is connected to the water recovery drain tank 60, and a hydrogen exhaust valve 62 is disposed in the fuel discharge line 56, and is discharged from the fuel chamber when the fuel cell stack 20 is started up. The hydrogen gas to be discharged can be discharged into the atmosphere. Note that a hydrogen combustor may be provided in the fuel discharge line 56 as necessary. The hydrogen gas discharged by the hydrogen combustor can be combusted to form water, and then discharged into the atmosphere.

  Here, the first hydrogen supply pressure regulating valve 25a and the second hydrogen supply pressure regulating valve 25b are a butterfly valve, a regulator valve, a diaphragm valve, a mass flow controller, a sequence valve, and the like. Any type may be used as long as the pressure of the hydrogen gas flowing out from the outlets of the supply pressure regulating valve 25a and the second hydrogen supply pressure regulating valve 25b can be adjusted to a preset pressure. The pressure adjustment may be performed manually, but is preferably performed by an actuator including an electric motor, a pulse motor, an electromagnet, or the like. The fuel supply electromagnetic valve 26 and the hydrogen exhaust valve 62 are so-called on-off types, and are actuated by actuators such as an electric motor, a pulse motor, and an electromagnet. The fuel storage means original opening / closing valve 24 is operated manually or automatically using an electromagnetic valve. Further, the suction circulation pump 36 may be of any kind as long as it is capable of forcibly discharging hydrogen gas and bringing the fuel chamber into a negative pressure state.

  On the other hand, air as an oxidant is supplied from an air supply fan 75 as an oxidant supply source through an oxidant supply pipe 76 to the oxygen chamber of the fuel cell stack 20. As the oxidant supply source, an air cylinder, an air tank, or the like can be used instead of the air supply fan 75. Further, oxygen can be used as the oxidant instead of air. The air discharged from the oxygen chamber is discharged into the atmosphere through the exhaust manifold 77.

  In addition, in order to maintain the unit cell 11 in a wet state from the air electrode side as the oxygen electrode of the fuel cell stack 20, water can be sprayed and supplied to the air supplied to the oxygen chamber. In this case, for example, water supplied from a tank for storing water is sprayed into the air through a water supply nozzle disposed in the middle of the oxidant supply pipe 76 or at the inlet of the oxygen chamber of the fuel cell stack 20. It is desirable. Further, it is desirable to arrange a condenser in the middle of the exhaust manifold 77 to collect and reuse water contained in the air discharged from the oxygen chamber.

  Incidentally, the air supplied to the oxygen chamber of the fuel cell stack 20 may be in a normal pressure state where the pressure is about atmospheric pressure, or in a state where the pressure is increased so as to be higher than the atmospheric pressure. However, in the present embodiment, the description will be made assuming that the pressure is applied. That is, the fuel cell system in the present embodiment is not a so-called normal pressure system but a pressurization system.

  FIG. 2 shows a closed cooling system device that is one of a plurality of cooling systems for cooling the fuel cell stack 20. Connected to the fuel cell stack 20 are a refrigerant supply line 53 through which refrigerant supplied to the fuel cell stack 20 passes and a refrigerant discharge pipe 71 through which refrigerant discharged from the fuel cell stack 20 passes. Yes. A refrigerant storage container 52 is connected to the ends of the refrigerant supply pipe 53 and the refrigerant discharge pipe 71 opposite to the fuel cell stack 20. The refrigerant supply pipe 53 is provided with a refrigerant supply pump 54 as a refrigerant pump and a filter 55. Further, a radiator 72 as a cooling device for cooling the refrigerant and a refrigerant discharge pump 51 as a refrigerant pump are disposed in the refrigerant discharge pipe 71. Here, the refrigerant is, for example, water, but may be antifreeze or any kind of fluid. The refrigerant discharge pump 51 and the refrigerant supply pump 54 may be of any type as long as they can suck and discharge a refrigerant such as water. The filter 55 may be of any type as long as it removes dust, impurities, etc. contained in a coolant such as water.

  And the refrigerant | coolant supplied to the fuel cell stack 20 distribute | circulates in the refrigerant | coolant flow path 45 formed in the separator main body 41 mentioned later of the separator unit 12 in each cell module 10, and cools each cell module 10. FIG. . In this case, the refrigerant circulates in the substantially closed cooling system formed by connecting the refrigerant storage container 52, the refrigerant supply pipe 53, the fuel cell stack 20, and the refrigerant discharge pipe 71, and the unit cell 11. There is no contact. Therefore, since the refrigerant does not come into contact with members such as the solid polymer electrolyte membrane, catalyst, and electrode constituting the unit cell 11, there is a possibility of affecting the members constituting the unit cell 11 such as an antifreeze liquid. Even a refrigerant containing a certain component can be used.

  The hydrogen gas supplied to the fuel chamber of the fuel cell stack 20 and the air supplied to the oxygen chamber also have a function of cooling the fuel cell stack 20. Therefore, an apparatus for supplying hydrogen gas as a fuel gas and air as an oxidant to the fuel cell stack 20 functions as one of the cooling systems for cooling the fuel cell stack 20. And since hydrogen gas and air are consumed or discharged | emitted outside, it can be said that the apparatus which supplies hydrogen gas and air is an open cooling system. In this case, the hydrogen gas and air flow through the cell module 10 while being in contact with members such as a solid polymer electrolyte membrane, a catalyst, and an electrode constituting the unit cell 11, thereby cooling the cell module 10. As described above, when water is supplied into the air supplied to the oxygen chamber, the cooling capacity is improved.

  The fuel cell stack 20 includes a voltmeter 78 that measures a terminal voltage of an electric terminal (not shown), and an exhaust air temperature that detects the temperature of air flowing through the fuel cell stack 20 or air discharged from the fuel cell stack 20. A total of 74 is attached. Water level sensors 52 a and 60 a for detecting the water level are attached to the refrigerant storage container 52 and the water recovery drain tank 60.

  The secondary battery as the power storage means is a so-called battery (storage battery), and a lead storage battery, a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, a sodium sulfur battery, and the like are common. The power storage means does not necessarily have to be a battery, and electrically stores and discharges energy, such as a capacitor (capacitor) such as an electric double layer capacitor, a flywheel, a superconducting coil, and a pressure accumulator. Any form may be used as long as it has a function. Furthermore, any of these may be used alone, or a plurality of them may be used in combination.

  The fuel cell stack 20 is connected to a load (not shown) and supplies the generated current to the load. Here, the load is generally an inverter device that is a drive control device, and converts a direct current from the fuel cell stack 20 or the power storage means into an alternating current to rotate a vehicle wheel. To supply. Here, the drive motor also functions as a generator, and generates a so-called regenerative current when the vehicle is decelerated. In this case, since the drive motor is rotated by the wheel to generate electric power, the wheel is braked, that is, functions as a vehicle braking device (brake). Then, the regenerative current is supplied to the power storage means, and the power storage means is charged.

  In the present embodiment, the fuel cell system has a control system as shown in FIG. In FIG. 3, reference numeral 81 denotes a type of computer that includes an arithmetic means such as a CPU and MPU, an input / output interface, and the like, and is a control device that controls the operation of the fuel cell system. The control device 81 is connected to a memory 82 as storage means such as a magnetic disk or a semiconductor memory. The control device 81 includes the voltmeter 78, the water level sensors 52a and 60a, the hydrogen pressure sensors 27 and 28, the exhaust air thermometer 74, and the hydrogen gas concentration discharged from the fuel chamber of the fuel cell stack 20. A hydrogen concentration sensor 83 to be detected is connected, and outputs of these various sensors are input to the control device 81. Further, the control device 81 includes the first hydrogen supply pressure regulating valve 25a and the second hydrogen supply pressure regulating valve 25b, a hydrogen exhaust valve 62, an air supply fan 75, a refrigerant supply pump 54 as a refrigerant pump, and a refrigerant discharge pump. 51, and an alarm 86 as a device for outputting an alarm when a failure, an accident, or the like occurs in the fuel cell system, and the operation of these devices is controlled by the control device 81.

  Next, the configuration of the separator unit 12 will be described in detail.

  FIG. 1 is a diagram showing a configuration of a separator unit of a fuel cell system according to a first embodiment of the present invention, and FIG. 5 is a sectional view showing a configuration of a cell module of the fuel cell system according to the first embodiment of the present invention. FIG. 6 is a diagram showing the power generation performance of the fuel cell system according to the first embodiment of the present invention.

  As shown in FIGS. 1 and 5, the cell module 10 includes a unit cell 11, a fuel chamber as a flow path for hydrogen gas introduced into the unit cell 11, while electrically connecting the unit cells 11 to each other. And a separator unit 12 that separates the oxygen chamber as an air flow path, and a plurality of them are stacked. 1 is an enlarged perspective view showing only a part of the stacked cell modules 10, and FIG. 5 is an enlarged sectional view showing only a part of the stacked cell modules 10. For convenience, the frame supporting the unit cell 11 and the separator unit 12 is omitted.

  As shown in FIG. 5, the unit cell 11 includes a solid polymer electrolyte membrane 11a as an electrolyte layer that is an ion exchange membrane, and an oxygen electrode provided on one side of the solid polymer electrolyte membrane 11a. It consists of an air electrode (cathode electrode) 11b and a fuel electrode (anode electrode) 11c provided on the other side. The air electrode 11b and the fuel electrode 11c are formed on the electrode diffusion layer made of a conductive material that permeates while diffusing the reaction gas, and are supported in contact with the solid polymer electrolyte membrane 11a. And a catalyst layer containing a catalyst material. In FIG. 1, the solid polymer electrolyte membrane 11a, the air electrode 11b, and the fuel electrode 11c are not shown.

  In addition, the separator unit 12 is provided on one side of the separator body 41 as a gas blocking member between the unit cells 11 and the electrode diffusion layer on the air electrode 11b side of the unit cell 11 and is collected. The air electrode side collector 14 as a mesh-like current collector in which a large number of openings that allow electricity and permeate the mixed flow of air and water are formed, and the fuel of the unit cell 11 provided on the other side of the separator body 41 A fuel electrode side collector 15 as a mesh current collector for contacting the electrode diffusion layer on the electrode 11c side and leading out current to the outside. In FIG. 1, the illustration of the fuel electrode side collector 15 is omitted for convenience of explanation.

  The air electrode side collector 14 and the fuel electrode side collector 15 are formed of a conductive plate material, for example, a metal thin plate having a plate thickness of about 0.2 mm. The separator body 41 is a plate-like member made of a thin metal plate having a thinner plate thickness. For example, the separator body 41 has a double structure including a first plate member 41a and a second plate member 41b and is shown inside. Such a refrigerant flow path 45 is formed. As the constituent metal of the air electrode side collector 14, the fuel electrode side collector 15 and the separator body 41, a metal having conductivity and corrosion resistance (for example, stainless steel, nickel alloy, titanium alloy, etc., such as gold plating). The thing which gave the corrosion-resistant electroconductive process is mentioned.

  Further, the air electrode side collector 14 has a generally horizontally long rectangular shape and is made of a porous body. The porous body is, for example, a metal plate material such as expanded metal or punching metal having a mesh-like opening having an opening ratio of 59% or more, and is a corrugated plate having fine ridges formed by pressing. . In addition, the said protruding item | line is provided with the side wall part 14b and the top part 14c. And the said protruding item | line is the arrangement | positioning which extends in the vertical direction of a board | plate material, ie, the up-down direction in FIG. The cross-sectional shape of the ridges is roughly a rectangular wave-shaped cross section, and the base side has a slightly flared shape due to the punching of the press work. The height of the ridges is substantially equal to the thickness of a frame (not shown), so that, in the stacked state, between the electrode diffusion layer on the air electrode 11b side of the unit cell 11 and the side surface of the separator body 41. An air flow path having a predetermined opening area penetrating in the vertical direction is secured. In FIG. 1, an arrow A indicates the flow of air introduced into the unit cell 11 and flowing through the oxygen chamber. Here, the flat surface of the top 14c of each protrusion is a separator contact portion that contacts the side surface of the separator body 41, and the flat surface of the valley 14a between the protrusions is on the air electrode 11b side of the unit cell 11. This is an electrode contact portion that contacts the electrode diffusion layer.

  The fuel electrode side collector 15 is a porous body having the same dimensions as the air electrode side collector 14, and is made of, for example, a metal plate material such as expanded metal or punching metal having a mesh-like opening, and is formed by pressing. The corrugated sheet has fine ridges. And the said protruding item | line is provided with the side wall part 15b and the top part 15c similarly to the case of the air electrode side collector 14, is extended in the up-down direction in FIG. 5, and cuts a plate | board surface completely at equal intervals in parallel. It is supposed to be arranged. The cross-sectional shape of the ridges is roughly a rectangular wave-shaped cross-section, and the base side has a slightly flared shape due to die cutting in press working. The height of the ridges is substantially equal to the thickness of a frame (not shown), so that, in the stacked state, the gap between the electrode diffusion layer on the fuel electrode 11c side of the unit cell 11 and the side surface of the separator body 41. A fuel gas flow path having a predetermined opening area penetrating in the vertical direction is secured. Further, the flat surface of the top portion 15c of each protrusion is a separator contact portion that contacts the side surface of the separator main body 41, and the flat surface of the valley portion 15a of each protrusion is an electrode on the fuel electrode 11c side of the unit cell 11. It is an electrode contact portion that contacts the diffusion layer.

  The air electrode side collector 14 and the fuel electrode side collector 15 are arranged with the separator body 41 interposed therebetween so that the valley portions 14a and 15a are both outside. At this time, the top portions 14c and 15c of the ridges of the air electrode side collector 14 and the fuel electrode side collector 15 are in contact with the separator main body 41, and can be energized with each other. Further, by superposing the air electrode side collector 14 and the fuel electrode side collector 15 on the separator body 41, an air flow path, that is, an oxygen chamber is formed on one side of the separator body 41, and a fuel gas flow path on the other side. That is, a fuel chamber is formed. Then, air is supplied from the oxygen chamber to the air electrode 11b of the unit cell 11, and similarly, hydrogen gas is supplied from the fuel chamber to the fuel electrode 11c of the unit cell 11.

  In the unit cell 11, water moves. That is, when hydrogen gas is supplied as a fuel gas into the fuel chamber in which the fuel electrode side collector 15 is disposed, hydrogen is decomposed into hydrogen ions (protons) and electrons, and the hydrogen ions are accompanied by proton-entrained water and become solid. It penetrates the polymer electrolyte membrane 11a. Further, when the air electrode 11b is used as a cathode electrode and air as an oxidant is supplied into the oxygen chamber, oxygen in the air is combined with the hydrogen ions and electrons to generate water. Furthermore, moisture permeates through the solid polymer electrolyte membrane 11a as reverse diffusion water and moves into the fuel chamber. Here, the reverse diffusion water means that water generated in the oxygen chamber diffuses into the solid polymer electrolyte membrane 11a and permeates through the solid polymer electrolyte membrane 11a in the direction opposite to the hydrogen ions to enter the fuel chamber. It has penetrated until.

  The separator main body 41 is connected to a refrigerant inflow pipe and a refrigerant outflow pipe (not shown), and the refrigerant flowing from the refrigerant inflow pipe passes through the refrigerant flow path 45 formed in the separator main body 41 as indicated by an arrow B. Then, it cools and flows out from the refrigerant outflow pipe. The refrigerant is a refrigerant in a closed cooling system device, and is supplied to the fuel cell stack 20 through the refrigerant supply pipe 53 and passes through a flow path (not shown) formed in the fuel cell stack 20. It flows into the inflow pipe. Further, the refrigerant flowing out from the refrigerant outflow pipe flows into the refrigerant discharge pipe 71 through a flow path (not shown) formed in the fuel cell stack 20 and is discharged from the fuel cell stack 20. The shape of the refrigerant flow path 45 may be a straight line, or may be a shape such as a serpentine shape, a spiral shape, or the like in which the refrigerant flow path length is long.

  In the example shown in FIG. 1, the separator body 41 is formed by pasting together a first plate member 41 a and a second plate member 41 b. In this case, a concave groove having a desired shape is formed on the inner surface of the second plate member 41b as one plate material using, for example, a photolithography technique such as chemical etching. And the separator main body 41 provided with the refrigerant | coolant flow path 45 can be obtained by superimposing the 1st board member 41a as the other board | plate material on the surface in which this concave groove was formed. In this case, since the surfaces on both sides of the separator body 41 are joined at various places, the electrical conductivity between the surfaces on both sides can be improved. Further, it is desirable that both outer surfaces of the separator main body 41 are flat surfaces having no irregularities. Thereby, the contact between the outer surface of the separator body 41 and the top portions 14c and 15c of the air electrode side collector 14 and the fuel electrode side collector 15 is ensured, and the separator body 41, the air electrode side collector 14 and the fuel electrode are secured. The thermal conductivity and electrical conductivity with the side collector 15 can be improved.

In the present embodiment, the air electrode side collector 14 and the fuel electrode side collector 15 are formed so that the aperture ratio changes locally. For example, the valley portions 14a and 15a as the MEA contact portions that are the electrode contact portions that contact the unit cell 11 have the highest opening ratio, and the top portion 14c as the separator contact portion that is the separator contact portion that contacts the separator body 41. 15c has the lowest opening ratio, and the opening ratios of the side walls 14b and 15b as ribs constituting the ribs are intermediate between the opening ratios of the valleys 14a and 15a and the opening ratios of the tops 14c and 15c. Has been. Note that the opening ratios of the side wall portions 14b and 15b may be equal to the opening ratios of the top portions 14c and 15c. That is, the aperture ratios of the air electrode side collector 14 and the fuel electrode side collector 15 are inclined with respect to the stacking direction of the unit cells 11 (the vertical direction in FIG. 5), and are defined by the following equation (1). Change.
Opening ratio of MEA contact part> Opening ratio of rib part ≧ Opening ratio of separator contact part (1)
Here, since the air electrode side collector 14 and the fuel electrode side collector 15 have a mesh-shaped opening, the air electrode side collector 14 and the fuel electrode side collector 15 inhibit the flow of the air in the oxygen chamber and the hydrogen gas in the fuel chamber. It will not be done. That is, the air in the oxygen chamber and the hydrogen gas in the fuel chamber fully contact the electrode diffusion layers of the air electrode 11b and the fuel electrode 11c of the unit cell 11 through the openings of the valley portions 14a and 15a that are in contact with the unit cell 11. can do. Furthermore, since the air in the oxygen chamber and the hydrogen gas in the fuel chamber can also move through the openings in the side wall portions 14b and 15b, the flow of air in the oxygen chamber and the flow of hydrogen gas in the fuel chamber become smooth.

  In particular, when water droplets are generated in the oxygen chamber due to generated water or water supplied to the air, and the water droplets block the flow path between the adjacent valley portions 14a, the air is adjacent through the opening of the side wall portion 14b. Therefore, the air flow is not hindered. The same applies when water droplets are generated in the fuel chamber due to the reverse diffusion water.

  The unit cell 11 is cooled by a separator body 41 that functions as a cooler for a closed cooling system. That is, the heat generated in the unit cell 11 is transmitted to the separator body 41 through the air electrode side collector 14 and the fuel electrode side collector 15, and is transmitted to the refrigerant flowing through the separator body 41. Similarly, the electricity generated in the unit cell 11 is also well transmitted to the air electrode side collector 14 and the fuel electrode side collector 15.

  The heat generated in the unit cell 11 is transmitted to the valley portions 14a and 15a from the outer surfaces of the air electrode 11b and the fuel electrode 11c, and is transmitted from the top portions 14c and 15c to the separator body 41 through the side wall portions 14b and 15b. Is done. Therefore, if the aperture ratios of the air electrode side collector 14 and the fuel electrode side collector 15 are constant in all parts, the thermal conductivity in the air electrode side collector 14 and the fuel electrode side collector 15 is It becomes constant at. In this case, since the areas of the valleys 14a and 15a are larger than the areas of the tops 14c and 15c, the amount of heat per unit area transferred in the tops 14c and 15c is larger than the amount of heat per unit area transferred in the valleys 14a and 15a. Becomes larger, and the thermal resistance at the tops 14c and 15c becomes larger than the thermal resistance at the valleys 14a and 15a. Moreover, also in the side wall parts 14b and 15b, when an aperture ratio is large, thermal conductivity will become low and thermal resistance will become large. In particular, when water is supplied into the air, the side walls 14b and 15b function as cooling fins as a kind of cooler. In this case, if the aperture ratio is large, the area functioning as the cooling fins decreases. In addition, the thermal resistance increases. Then, when the thermal resistance in the valley portions 14a and 15a and the side wall portions 14b and 15b increases, as described in the section “Problems to be solved by the invention”, a temperature distribution occurs in the stacking direction of the unit cells 11, The temperature of the air electrode 11b and the fuel electrode 11c will rise. Therefore, the amount of moisture dissipated to the outside of the unit cell 11 through the air electrode 11b and the fuel electrode 11c is excessively increased, and the humidity inside the unit cell 11 is lowered, so that the power generation efficiency in the unit cell 11 is lowered.

  However, in the present embodiment, the aperture ratios of the air electrode side collector 14 and the fuel electrode side collector 15 are inclined with respect to the stacking direction of the unit cells 11 and change as defined by the above formula (1). To do. Therefore, since the top portions 14c and 15c have a low aperture ratio and a high surface density, the amount of heat that can be transmitted per unit area increases, and the thermal resistance decreases. Further, since the side wall portions 14b and 15b also have a low aperture ratio and a high surface density, the amount of heat that can be transferred per unit area increases, and the thermal resistance decreases. As a result, the temperature distribution in the stacking direction of the unit cells 11 is eliminated, and the temperature of the air electrode 11b and the fuel electrode 11c does not rise. Therefore, the unit cell 11 passes through the air electrode 11b as shown by the arrow C in FIG. And the amount of moisture dissipated to the outside of the unit cell 11 through the fuel electrode 11c as indicated by the arrow D in FIG. Therefore, the humidity inside the unit cell 11 can be properly maintained, and the power generation efficiency in the unit cell 11 can be improved.

  FIG. 6 shows a comparison of power generation performance depending on the aperture ratio of the air electrode side collector 14 and the fuel electrode side collector 15 in a low humidification condition, that is, in a state where the unit cell 11 is relatively dry. In FIG. 6, the vertical axis represents the voltage in the unit cell 11 and the horizontal axis represents the current density. A line 47 connecting the experimental results plotted with ▲ indicates a case where the aperture ratios of the air electrode side collector 14 and the fuel electrode side collector 15 are constant in all parts, and a line connecting the experimental results plotted with ◆. Reference numeral 48 denotes a case where the aperture ratios of the air electrode side collector 14 and the fuel electrode side collector 15 are inclined with respect to the stacking direction of the unit cells 11 and change as defined by the above formula (1). From FIG. 6, when the aperture ratios of the air electrode side collector 14 and the fuel electrode side collector 15 are inclined with respect to the stacking direction of the unit cells 11 and change as defined by the above formula (1), the unit cell 11 It can be seen that the power generation efficiency is improved.

  Further, since the air electrode side collector 14 and the fuel electrode side collector 15 have a mesh-like opening, the flow of the air in the oxygen chamber and the hydrogen gas in the fuel chamber is hindered by the air electrode side collector 14 and the fuel electrode side collector 15. There is nothing. That is, the air in the oxygen chamber and the hydrogen gas in the fuel chamber fully contact the electrode diffusion layers of the air electrode 11b and the fuel electrode 11c of the unit cell 11 through the openings of the valley portions 14a and 15a that are in contact with the unit cell 11. can do. Further, since the air in the oxygen chamber and the hydrogen gas in the fuel chamber can also move through the openings of the side wall portions 14b and 15b, the flow of air in the oxygen chamber and the flow of hydrogen gas in the fuel chamber become smooth. In particular, when water droplets are generated in the oxygen chamber due to generated water or water supplied to the air, and the water droplets block the flow path between the adjacent valley portions 14a, the air is adjacent through the opening of the side wall portion 14b. Therefore, the air flow is not hindered. The same applies when water droplets are generated in the fuel chamber due to the reverse diffusion water.

  Next, a method for manufacturing the air electrode side collector 14 and the fuel electrode side collector 15 having the above-described configuration will be described. Since the method for manufacturing the air electrode side collector 14 and the fuel electrode side collector 15 is substantially the same, only the method for manufacturing the air electrode side collector 14 will be described here, and the fuel electrode side collector 15 is manufactured. Description of the method to do is omitted.

  FIG. 7 is a plan view showing a first stage of the method of manufacturing the air electrode side collector according to the first embodiment of the present invention, and FIG. 8 manufactures the air electrode side collector according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view showing a first stage of the method, a cross-sectional view taken along the line E-E of FIG. 7, and FIG. 9 is a plan view showing a second stage of the method of manufacturing the air electrode side collector according to the first embodiment of the present invention; 10 and 10 are cross-sectional views showing a second stage of the method of manufacturing the air electrode side collector according to the first embodiment of the present invention, and are cross-sectional views taken along line FF in FIG.

  First, a collector base material 141 as shown in FIGS. 7 and 8 is prepared. The collector base material 141 is a metal plate material such as an expanded metal or a punching metal having a mesh-like opening with a relatively small opening ratio, and is a corrugated porous plate having fine ridges. Here, the ridges extend in the longitudinal direction of the collector base material 141, that is, the vertical direction in FIG. 7, and are arranged so as to completely cut the surface of the collector base material 141 at equal intervals in parallel. Yes. The convex valley portion 141a as shown in FIG. 8 corresponds to the above-described valley portion 14a of the air electrode side collector 14, and the convex side wall portion 141b is the side wall portion of the air electrode side collector 14 described above. 14b corresponds to the top portion 14c of the air electrode side collector 14 described above. In FIG. 8, for convenience of illustration, the valley 141a is located on the upper side, and the top 141c is located on the lower side.

  Here, the collector base material 141 can be obtained as follows.

  First, a base collector material made of a flat strip-shaped collector base material 141, that is, a strip plate having a mesh-like opening, on a mounting jig having a plurality of parallel streaky recesses formed on the surface. Is placed. Subsequently, a pressing jig having a plurality of parallel streaky protrusions formed on the surface is pressed against the base collector material on the mounting jig from above to press the base collector material. At this time, the convex portion of the pressing jig is fitted into the concave portion of the mounting jig. Thereby, the base collector material in the range sandwiched between the concave portion of the mounting jig and the convex portion of the pressing jig is formed into an uneven shape.

  Subsequently, after raising the pressing jig, the base collector material is moved in the longitudinal direction. The moving distance at this time is a distance corresponding to the length of the range sandwiched between the concave portion of the mounting jig and the convex portion of the pressing jig. Then, the pressing jig is pressed against the base collector material on the mounting jig from above to press the base collector material. Thereafter, the base collector material made of a strip is formed into a concavo-convex shape over the entire range by sequentially repeating the above-described operations. Thereby, the collector base material 141 as a corrugated porous plate having fine ridges can be obtained.

  Next, as shown in FIG. 7, the valley portion 141 a of the deletion range 142 surrounded by a dotted line as a predetermined range is deleted. The range 142 can be arbitrarily set. In this case, as shown in FIG. 8, the deletion range 142 includes only the valley portion 141a and does not include the side wall portion 141b and the top portion 141c. That is, as shown in FIG. 7, the side wall portion 141 b and the top portion 141 c are not deleted even if they are included in the deletion range 142 in the plane.

  Here, the valley 141a can be removed by fine electrical discharge machining.

  Generally, a fine electric discharge machine has a processing tank mounted on an XY table and an electrode disposed on the processing tank. And the collector base material 141, ie, a to-be-processed object, is hold | maintained in the said processing tank in the state with which the processing liquid which is an insulator was satisfy | filled in the said processing tank. At the time of processing, the desired part of the workpiece is processed by moving the workpiece by operating the XY table. The electrode is moved up and down while rotating around the Z axis in a state where a predetermined voltage is applied. When the distance between the workpiece and the electrode reaches a predetermined distance in the machining fluid, dielectric breakdown occurs and electric discharge occurs. The desired part of the workpiece is cut by the energy generated by the discharge.

  Next, a joining member 143 having a shape and size corresponding to the deletion range 142 is prepared. The joining member 143 is a metal plate material such as an expanded metal or a punching metal having a mesh-like opening having a relatively large opening ratio, and is a flat plate. The joining member 143 may be made of the same material as the collector base material 141 or may be made of a different material. The shape of the joining member 143 can be formed by, for example, fine electrical discharge machining. As shown in FIG. 9, the joining member 143 is disposed so as to close the deletion range 142. That is, the deleted valley portion 141 a is replaced by the bonding member 143.

  Next, the bonding member 143 is bonded to the collector base material 141 by diffusion bonding. In this case, as shown in FIG. 10, the surface of the joining member 143 on the top 141c side and the side wall 141b are joined. And the joined joining member 143 functions as the trough part 14a of the air electrode side collector 14 with a large aperture ratio. Thereby, the air electrode side collector 14 in which the opening ratio of the valley portion 14a as the MEA contact portion is larger than the opening ratio of the side wall portion 14b as the rib portion and the top portion 14c as the separator contact portion can be obtained.

  In this case, since the bonding member 143 and the collector base material 141 are bonded by diffusion bonding, the opening in the vicinity of the bonded portion is not blocked. Therefore, the obtained air electrode side collector 14 has a predetermined aperture ratio. Further, the thickness of the joint portion does not become thicker than other portions. Therefore, the obtained air electrode side collector 14 has a predetermined dimension, and the distance between the unit cell 11 and the separator body 41 can be maintained at a predetermined numerical value. Furthermore, other metal components are not mixed. Therefore, the function of the unit cell 11 is not affected by unexpected metal components. On the other hand, for example, when the joining member 143 and the collector base material 141 are joined by welding, the opening in the vicinity of the joining portion is blocked, and the obtained air electrode side collector 14 has a predetermined opening ratio. Not. Further, since the thickness of the joint portion is thicker than other portions, the distance between the unit cell 11 and the separator body 41 cannot be maintained at a predetermined value. Furthermore, since other metal components contained in the welding material or the like are mixed, the function of the unit cell 11 may be affected.

  Here, the diffusion bonding between the bonding member 143 and the collector base material 141 can be performed as follows.

  Diffusion bonding is performed by bringing the metal surfaces of the bonding material close to each other at a distance of the atomic level and controlling the conditions such as heating, pressurization, vacuum, time, etc. without dissolving the base material. This is a technique that enables the formation and bonding of metal bonds between bonding materials by controlling interdiffusion between materials. In this case, a vacuum high-temperature furnace is used, and the furnace temperature is maintained at a temperature of 60 to 70% of the melting point of the bonding material. For example, when the joining material is stainless steel, the furnace temperature is maintained at about 1000 [° C.]. Then, the bonding member 143 and the collector base material 141 fixed with a jig and given a predetermined load, that is, the bonding material, are placed in the furnace for a predetermined time, for example, 12 hours. Thereby, the joining member 143 and the collector base material 141 can be joined by diffusion joining.

  Although only the method for manufacturing the air electrode side collector 14 has been described here, the fuel electrode side collector 15 is also manufactured by the same method.

  Next, the operation of the fuel cell system having the above configuration will be described.

  FIG. 11 is a flowchart showing the start-up operation of the fuel cell system according to the first embodiment of the present invention. FIG. 12 is a flowchart showing the air supply amount control operation of the fuel cell system according to the first embodiment of the present invention. is there.

  First, the operation at startup will be described. In order to start the fuel cell system, the operator turns on a start switch (not shown) (step S1). Then, the refrigerant supply pump 54 and the refrigerant discharge pump 51, that is, the refrigerant pump is turned on (step S2), the refrigerant circulation is started, and the refrigerant flows through the refrigerant channel 45 in the separator body 41. Subsequently, an apparatus for supplying air as an oxidant to the fuel cell stack 20, that is, an air supply system is turned on (step S3). In this case, in order to prevent an abnormal reaction from occurring in the unit cell 11 of the fuel cell stack 20, the amount of air supplied from the air supply fan 75 is controlled to be maximum. Subsequently, an apparatus for supplying hydrogen gas as fuel gas to the fuel cell stack 20, that is, a hydrogen supply system is turned on (step S4), and the start-up operation ends. As a result, the operation shifts to steady operation, and the current generated by the fuel cell stack 20 is supplied to the load and the secondary battery.

  In the case where the fuel cell system has an apparatus for spraying and supplying water into the air supplied to the oxygen chamber, the air supplied to the oxygen chamber before the hydrogen supply system is turned on. It is desirable to start supplying water into it. This is because, at the time of start-up, air is present in the unit cell 11 regardless of whether the air supply system is on or not, so that hydrogen gas is supplied in a state where the solid polymer electrolyte membrane 11a is dry. This is because abnormal combustion may occur. Therefore, even when abnormal heat is generated due to abnormal combustion, water is supplied before supplying hydrogen gas so that the unit cell 11 is not damaged, and the air electrode 11b of the unit cell 11 is wetted in advance. (Nu) needs to be kept. Thereby, abnormal heat can be converted into the heat of water evaporation, and further, wetting of the solid polymer electrolyte membrane 11a can be promoted to prevent damage to the unit cell 11 beforehand.

In addition, after starting operation is complete | finished, hydrogen gas supply amount control, air supply amount control, and water supply amount control are performed in parallel. In the hydrogen gas supply amount control, the first hydrogen supply pressure regulating valve 25a and the second hydrogen supply pressure regulating valve 25b are adjusted so that hydrogen gas is supplied to the fuel electrode at a predetermined concentration below the explosion limit. Then, the hydrogen exhaust valve 62 that is closed at the time of startup is opened based on a predetermined rule, the fuel gas having a reduced hydrogen partial pressure is exhausted, and the atmosphere gas at the fuel electrode is refreshed. The predetermined rule at this time is stored in the memory 82, and the control of the first hydrogen supply pressure regulating valve 25a and the second hydrogen supply pressure regulating valve 25b and the opening and closing of the hydrogen exhaust valve 62 are performed by the control device. 81 is executed by reading the rule from the memory 82. The reason why the hydrogen exhaust valve 62 is appropriately opened during operation is that the operation of the fuel cell system is continued with the hydrogen exhaust valve 62 closed, due to the influence of N ₂ , O ₂ or generated water that permeates from the air electrode 11b. This is because the partial pressure of hydrogen consumed in the fuel electrode 11c gradually decreases, and the output voltage of the fuel cell stack 20 also decreases accordingly, and a stable voltage cannot be obtained.

  In the air supply amount control, first, the temperature of the discharged air immediately after being discharged from the fuel cell stack 20 is detected by the discharged air thermometer 74 (step S11). Then, the control device 81 determines whether or not the detected temperature of the exhaust air is 80 [° C.] or less (step S12). Here, if the temperature of the discharged air is not 80 [deg.] C. or lower, i.e., exceeds 80 [[deg.] C.], the unit cell 11 may be seized, so the control device 81 increases the air volume (step S13). . Specifically, the air supply amount is increased by increasing the rotation speed of the air supply fan 75, and the temperature of the air electrode 11b, which is a heat generation source, is decreased.

  On the other hand, when the temperature of the exhaust air is 80 [° C.] or less, the control device 81 detects the load of the fuel cell stack 20, that is, the FC main body (step S14). Then, the control device 81 determines whether or not the supply amount of air, that is, the air volume is optimal (step S15). In this case, the relationship between the load of the fuel cell stack 20 and the air volume required in that state is compared with the relationship stored in the table format in the memory 82 to determine whether the air volume is optimal. To do. If the air volume is not optimal, the control device 81 adjusts the air volume (step S16). Specifically, the air volume is adjusted by adjusting the rotation speed of the air supply fan 75. If the air volume is optimal, the process is terminated.

  In the hydrogen gas supply amount control, the hydrogen pressure sensors 27 and 28 detect the pressure of the hydrogen gas on the fuel storage means 73 side, and the controller 81 controls the first hydrogen supply pressure regulating valve 25a and the second hydrogen supply. By adjusting the pressure regulating valve 25b, the pressure of the hydrogen gas supplied to the fuel cell stack 20 is adjusted to a predetermined value. The control device 81 controls the supply of hydrogen gas to the fuel cell stack 20 by controlling the opening and closing of the fuel supply electromagnetic valve 26. Note that when the supply of hydrogen gas to the fuel cell stack 20 is shut off, the fuel supply electromagnetic valve 26 is closed.

  Thus, in the present embodiment, the air electrode side collector 14 and the fuel electrode side collector 15 are formed such that the aperture ratio changes locally, and are inclined with respect to the stacking direction of the unit cells 11. Therefore, the temperature distribution in the stacking direction of the unit cells 11 is eliminated, and the temperature of the air electrode 11b and the fuel electrode 11c does not increase. Therefore, the moisture dissipated to the outside of the unit cell 11 through the air electrode 11b and the fuel electrode 11c. The amount is suppressed. Thereby, the humidity inside the unit cell 11 can be properly maintained, and the power generation efficiency in the unit cell 11 can be improved. In this case, since the air electrode side collector 14 and the fuel electrode side collector 15 as current collectors are manufactured by joining a plurality of members having different aperture ratios, that is, the collector base material 141 and the joining member 143, the aperture ratio It is possible to easily manufacture the air electrode side collector 14 and the fuel electrode side collector 15 made of a porous body in which the gas is locally changed at low cost.

  Further, since the air electrode side collector 14 and the fuel electrode side collector 15 have a mesh-like opening, the flow of the air in the oxygen chamber and the hydrogen gas in the fuel chamber is hindered by the air electrode side collector 14 and the fuel electrode side collector 15. There is nothing. That is, the air in the oxygen chamber and the hydrogen gas in the fuel chamber are sufficiently in contact with the electrode diffusion layers on the air electrode side and the fuel electrode side of the unit cell 11 through the openings of the valley portions 14a and 15a that are in contact with the unit cell 11. can do.

  In the present embodiment, the side wall portions 14b and 15b and the top portions 14c and 15c of the air electrode side collector 14 and the fuel electrode side collector 15 have been described as having openings, but the side wall portions 14b and 15b and the top portion 14c and 15c may not have an opening.

  The air electrode side collector 14 in which the side wall portion 14 b and the top portion 14 c do not have an opening can be manufactured by using a metal plate made of a blank material having no opening as the collector base material 141. Note that the joining member 143 uses a metal plate material such as expanded metal or punching metal having a mesh-like opening. Then, by joining the collector base material 141 having no opening and the joining member 143 having a mesh-like opening placed so as to close the deletion range 142 of the collector base material 141 by diffusion joining, Although the valley portion 14a has an opening, the side wall portion 14b and the top portion 14c can have the air electrode side collector 14 having no opening. In addition, although the valley part 15a has an opening, the fuel electrode side collector 15 in which the side wall part 15b and the top part 15c do not have an opening can be obtained in the same manner.

  Next, a second embodiment of the present invention will be described. In addition, about what has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operation and the same effect as those of the first embodiment is also omitted.

  FIG. 13 is a two-sided view showing the configuration of the air electrode side collector in the second embodiment of the present invention, and FIG. 14 is an enlarged view of the main part showing the configuration of the air electrode side collector in the second embodiment of the present invention. It is a G section enlarged view of FIG. FIG. 13A is a plan view and FIG. 13B is a side view.

  13 and 14, reference numeral 145 denotes an air electrode side collector in the present embodiment. Since the fuel electrode side collector has substantially the same configuration as the air electrode side collector 145 and the manufacturing method is substantially the same, only the configuration and manufacturing method of the air electrode side collector 145 are described here. Explanation will be omitted, and the description of the fuel electrode side collector will be omitted.

  The air electrode side collector 145 in the present embodiment is a base collector material 146 as a flat plate perforated plate made of a metal plate material such as expanded metal or punching metal having a mesh-like opening, and one surface of the base collector material 146 And a linear member 147 as a linear body joined to the substrate.

  Here, the base collector material 146 is gold-plated on a metal having conductivity and corrosion resistance, for example, stainless steel, nickel alloy, titanium alloy, etc., like the air electrode side collector 14 in the first embodiment. It is made of a material subjected to a corrosion-resistant conductive treatment. The aperture ratio is, for example, 59% or more, but can be set arbitrarily.

  On the other hand, the linear member 147 is, for example, a member that does not have a solid wire-shaped or rod-shaped opening having a rectangular cross section, and a plurality of the linear members 147 are arranged in parallel to each other. The linear material 147 may be made of the same material as the base collector material 146 or may be made of a different material. Further, the cross-sectional shape of the linear member 147 may be a shape other than a rectangle, for example, a circle, an ellipse, a triangle, etc., and can be arbitrarily set. Further, the linear material 147 may be a hollow pipe.

  The linear material 147 is bonded to the surface of the base collector material 146 by diffusion bonding. The diffusion bonding method is the same as that in the first embodiment.

  Thereby, the air electrode side collector 145 provided with a some protruding item | line can be obtained. In this case, the base collector material 146 functions as a trough 145a as an MEA contact portion, both side portions of the linear material 147 function as side wall portions 145b as rib portions, and the top of the linear material 147 serves as a separator contact portion. It functions as the top part 145c. Since the valley portion 145a has an opening and the side wall portion 145b and the top portion 145c do not have an opening, the air electrode side collector 145 is the same as the air electrode side collector 14 in the first embodiment. Corresponds to the definition of the formula (1).

  Although only the air electrode side collector 145 has been described here, the fuel electrode side collector has the same configuration and is manufactured by the same method. Other points are the same as those in the first embodiment, and the description is omitted.

  Thus, in this Embodiment, the air electrode side collector 145 is manufactured by joining the linear material 147 to the base collector material 146 as a flat porous plate which has opening. Therefore, it can be easily manufactured at a low cost. The same applies to the fuel electrode side collector.

  The present invention is not limited to the above-described embodiment, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

It is a figure which shows the structure of the separator unit of the fuel cell system in the 1st Embodiment of this invention. It is a figure which shows the structure of the fuel cell system in the 1st Embodiment of this invention. It is a figure which shows the structure of the control system of the fuel cell system in the 1st Embodiment of this invention. It is a figure which shows the structure of the fuel cell stack in the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the cell module of the fuel cell system in the 1st Embodiment of this invention. It is a figure which shows the electric power generation performance of the fuel cell system in the 1st Embodiment of this invention. It is a top view which shows the 1st step of the method of manufacturing the air electrode side collector in the 1st Embodiment of this invention. It is sectional drawing which shows the 1st step of the method of manufacturing the air electrode side collector in the 1st Embodiment of this invention, and is EE arrow sectional drawing of FIG. It is a top view which shows the 2nd step of the method of manufacturing the air electrode side collector in the 1st Embodiment of this invention. It is sectional drawing which shows the 2nd step of the method of manufacturing the air electrode side collector in the 1st Embodiment of this invention, and is FF arrow sectional drawing of FIG. It is a flowchart which shows the starting operation | movement of the fuel cell system in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of air supply amount control of the fuel cell system in the 1st Embodiment of this invention. It is a two-plane figure which shows the structure of the air electrode side collector in the 2nd Embodiment of this invention. It is a principal part enlarged view which shows the structure of the air electrode side collector in the 2nd Embodiment of this invention, and is the G section enlarged view of FIG.

Explanation of symbols

11 Unit cell 11a Solid polymer electrolyte membrane 11b Air electrode 11c Fuel electrode 12 Separator unit 14, 145 Air electrode side collector 14a, 15a, 141a, 145a Valley part 14b, 15b, 141b, 145b Side wall part 14c, 15c, 141c, 145c Top 15 Fuel electrode side collector 20 Fuel cell stack 41 Separator body 141 Collector base material 142 Deletion range 146 Base collector material 147 Linear material

Claims (10)

A separator unit current collector sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode,
A separator abutting portion that abuts on a plate-shaped separator main body that cuts off a gas supplied to the fuel electrode and a gas supplied to the oxygen electrode; an electrode abutting portion that abuts the fuel electrode or the oxygen electrode; A rib portion connecting the separator contact portion and the electrode contact portion;
A current collector formed by joining a plurality of members having different aperture ratios.   The current collector according to claim 1, wherein the electrode contact portion is made of a member having an opening ratio larger than members of the separator contact portion and the rib portion.   The separator contact portion and the rib portion are made of a member obtained by deleting a trough portion of a corrugated porous plate having a first aperture ratio, and the electrode contact portion is a second larger than the first aperture ratio. The current collector according to claim 1 or 2, comprising a plate-like perforated plate having an aperture ratio, the member being joined to the corrugated plate-like perforated plate so as to close the deleted trough.   The current collector according to claim 3, wherein the first aperture ratio is zero.   The electrode contact portion is composed of a flat plate-like porous plate having a predetermined aperture ratio, and the separator contact portion and the rib portion are linear bodies that do not have an opening joined to one surface of the flat plate-like porous plate. The current collector according to claim 1 or 2, comprising: A method of manufacturing a current collector for a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode,
Delete the valley of the predetermined range of the corrugated porous plate having the first aperture ratio,
A flat aperture plate having a second aperture ratio larger than the first aperture ratio and corresponding to the predetermined range is joined to the corrugated porous plate so as to close the deleted trough. A method for producing a current collector.   The method for manufacturing a current collector according to claim 6, wherein the flat plate-like porous plate is joined to the corrugated plate-like porous plate by diffusion bonding. A method of manufacturing a current collector for a separator unit sandwiched between fuel cells in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode,
A method of manufacturing a current collector, comprising bonding a linear body having no opening to one surface of a flat porous plate having a predetermined opening ratio.   The manufacturing method of the electrical power collector of Claim 8 which joins the said linear body to a flat porous plate by diffusion bonding. The method for manufacturing a current collector according to claim 8 or 9, wherein a plurality of the linear bodies are arranged in parallel.

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