JP4992187B2 - Fuel cell stack and fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell stack and a fuel cell system.

  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 disposed 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 a fuel cell system, an amount of heat corresponding to the generated electric power is generated in each cell due to an electrochemical reaction. In particular, in a polymer type fuel cell operating at a low temperature, each cell heats up excessively. The cooling means which prevents it is provided. In this case, generally, a refrigerant path different from the reaction gas supply path is provided in the cell stack, and a refrigerant such as cooling water flows through the refrigerant path (see, for example, Patent Documents 1 and 2). .
JP-A-8-306371 JP 10-340734 A

  However, in the conventional fuel cell system, the shape and arrangement of the refrigerant passage are not appropriate, and it is difficult to sufficiently cool the fuel cell stack. Further, since the cooling capacity could not be adjusted appropriately, the temperature of the fuel cell stack could not be maintained at an appropriate temperature when the temperature change in the environment where the fuel cell system was placed was large.

  The present invention solves the above-mentioned conventional problems and cools the fuel cell stack with a plurality of cooling systems, so that the cooling capacity is high, and the cooling capacity can be easily and appropriately adjusted. Fuel cell stack and fuel cell capable of maintaining the temperature of the fuel cell stack at an appropriate temperature in a wide temperature range and in an environment with a large temperature change, and increasing the output of the fuel cell The purpose is to provide a system.

Therefore, in the fuel cell stack of the present invention, a fuel cell electrolyte layer was sandwiched between the fuel electrode and the oxygen electrode, a fuel cell stack are stacked to sandwich the separator unit, the separator unit, before A plate-shaped separator body that blocks fuel gas supplied to the fuel electrode and air supplied to the oxygen electrode, and a separate member from the separator body, provided on the oxygen electrode side of the separator body And a net-like current collector that radiates and collects heat generated in the fuel cell, and the separator body has a coolant channel formed therein for cooling the fuel cell. The electric body is a corrugated sheet including a plurality of parallel ridges formed by pressing a metal plate material having a mesh-shaped opening, and the metal plate material is formed between the ridges. Plane parts are in contact with the electrode contact portion to the electrode diffusion layer of the oxygen electrode, the top of the ridges Ri abuts separator abutment der the flat side of the separator main body, the top portion of the convex Is narrower than the width of the plane of the valley between the ridges .

In the fuel cell system of the present invention, the fuel cell in which the electrolyte layer is sandwiched between the fuel electrode and the oxygen electrode dissipates the heat generated in the refrigerant flow path and the fuel cell for cooling the fuel cell and collects the current. A fuel cell stack stacked with a separator unit having a mesh current collector, a fuel supply system supplying fuel gas to the fuel electrode, and supplying air to the oxygen electrode through the current collector an oxidant supply system, and a cooling system that supplies refrigerant to the refrigerant passage, the separator unit will shut off the air supplied to the fuel gas supplied to the pre-Symbol fuel electrode to the oxygen electrode A plate-like separator main body, and a member separate from the separator main body, provided on the oxygen electrode side of the separator main body, and radiating heat generated in the fuel cell and collecting current; The For example, the separator body has coolant channel for cooling the fuel cell is formed therein, said current collector, with consists of the metal plate material comprising a network of openings, by press working to the metal plate It is a corrugated plate having a plurality of parallel ridges formed, the plane of the valley between the ridges is an electrode contact portion that contacts the electrode diffusion layer of the oxygen electrode, the top of the ridge is the above separator abutting portion der abuts the flat side of the separator main body is, the width of the top of the ridges narrower than the width of the plane of the valley between the convex.

In another fuel cell system of the present invention, a thermometer for detecting a temperature of exhaust air exhausted from the oxygen electrode, and when the temperature of the exhaust air detected by the thermometer is a predetermined value or more, the oxygen And a controller that increases at least one of the amount of air supplied to the pole and the amount of refrigerant supplied to the refrigerant flow path.

  According to the present invention, in the fuel cell stack, the fuel cell in which the electrolyte layer is sandwiched between the fuel electrode and the oxygen electrode is stacked with the separator unit interposed therebetween, and the separator unit includes the separator A refrigerant flow path for cooling the fuel cell is formed inside, a plate-shaped separator body that blocks a gas supplied to the fuel electrode and a gas supplied to the oxygen electrode, and one side of the separator body Alternatively, it is provided on both sides, and has a mesh-like current collector that dissipates heat generated by the fuel cell and collects current.

  In this case, the cooling capacity is high, the cooling capacity can be adjusted easily and appropriately, and the temperature of the fuel cell stack is maintained at an appropriate temperature in a wide temperature range and in an environment with a large temperature change. Can increase the output. Further, since the current collector is mesh-shaped, the gas flow is not hindered by the current collector, and the pressure loss of the gas can be reduced.

  In another fuel cell stack, a fuel cell stack in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode is stacked with a separator unit interposed therebetween, and the separator unit includes the fuel electrode. A plate-like separator body that cuts off the gas supplied to the gas and the gas supplied to the oxygen electrode; and provided on one side of the separator body for cooling the fuel cell on the surface facing the separator body A plate-like current collector provided with a concave groove that forms a refrigerant flow path, a convex strip that forms a gas flow path on a surface facing the fuel electrode, and the other side of the separator body, And a net-like current collector that radiates and collects heat generated in the battery.

  In this case, the heat exchange efficiency between the refrigerant and the fuel cell can be improved, and the cooling capacity by the refrigerant can be improved. Therefore, the cooling capacity is high, the cooling capacity can be adjusted easily and appropriately, and the temperature of the fuel cell stack is maintained at an appropriate temperature in a wide temperature range and in an environment with a large temperature change. Can increase the output.

  Further, in the fuel cell system, the fuel cell in which the electrolyte layer is sandwiched between the fuel electrode and the oxygen electrode dissipates heat while collecting heat from the refrigerant flow path for cooling the fuel cell and the fuel cell. A fuel cell stack stacked with a separator unit having a mesh current collector interposed therebetween, a fuel supply system that supplies fuel gas to the fuel electrode, and an oxidation that supplies air to the oxygen electrode through the current collector An agent supply system and a cooling system for supplying the refrigerant to the refrigerant flow path.

  In this case, the cooling capacity is high, the cooling capacity can be adjusted easily and appropriately, and the temperature of the fuel cell stack is maintained at an appropriate temperature in a wide temperature range and in an environment with a large temperature change. Can increase the output.

  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. It is configured by overlapping multiple sets.

  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 pump 75 as an oxidant supply source through an oxidant supply line 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 pump 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, the catalyst, and the 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 pump 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 refrigerant formed in the separator body of the fuel cell system according to the first embodiment of the present invention. It is a figure which shows a flow path.

  As shown in FIG. 1, the cell module 10 includes a unit cell 11, an electrical connection between the unit cells 11, a fuel chamber as a flow path for hydrogen gas introduced into the unit cell 11, an air And a separator unit 12 that separates the oxygen chamber as a flow path, and a plurality of them are stacked. FIG. 1 is an enlarged perspective view showing only a part of the stacked cell modules 10 for convenience of explanation, and a frame for supporting the unit cell 11 and the separator unit 12 is omitted.

  The unit cell 11 includes a solid polymer electrolyte membrane as an electrolyte layer, an air electrode (cathode electrode) as an oxygen electrode provided on one side of the solid polymer electrolyte membrane, and a fuel electrode provided on the other side. (Anode electrode). The air electrode and the fuel electrode include a diffusion layer made of a conductive material that permeates while diffusing the reaction gas, and a catalyst that is formed on the diffusion layer and is supported in contact with the solid polymer electrolyte membrane. Consisting of layers. In FIG. 1, the solid polymer electrolyte membrane, the air electrode, and the fuel electrode 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 side of the unit cell 11 to collect current. In addition, an air electrode side collector 14 as a mesh-like current collector in which a large number of openings that allow a mixed flow of air and water to pass therethrough, and a fuel electrode of the unit cell 11 are provided on the other side of the separator body 41. And a fuel electrode side collector 15 as a mesh-like current collector for contacting the electrode diffusion layer on the side and leading out current to the outside. In FIG. 1, for convenience of explanation, illustration of the air electrode side collector 14 provided on one side of the separator main body 41 is omitted, and the air electrode side collector 14 in the adjacent separator unit 12, An air electrode side collector 14 is shown in contact with the electrode diffusion layer on the air electrode side.

  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 thickness of about 0.2 [mm]. Further, the separator body 41 is a plate-like member made of a thin metal plate having a thinner plate thickness, but has a double structure, and has a coolant channel 45 as shown in FIG. 5 formed therein. Yes. 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 is formed of a metal plate material such as an expanded metal having a net-like opening having an opening ratio of 59% or more, and is formed by pressing. The corrugated sheet has fine ridges 14b. The ridges 14b extend in the longitudinal direction of the plate material, that is, in the vertical direction in FIG. 1, and are arranged so as to completely cut the plate surface in parallel at equal intervals. The cross-sectional shape of the ridges 14b 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 14b 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 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. Moreover, the top part of each protruding item | line 14b becomes a contact part which contacts the side surface of the separator main body 41, and the plane of the trough part 14a between each protruding item | line 14b is the electrode diffusion layer by the side of the air electrode of the unit cell 11 It is the contact part which contacts.

The surface of the air electrode side collector 14 is desirably subjected to hydrophilic treatment. As a treatment method, a method of applying a hydrophilic treatment agent to the surface is employed. Examples of the treating agent to be applied include polyacrylamide, polyurethane resin, titanium oxide (TiO ₂ ), and the like. Examples of other hydrophilic treatment include treatment for roughening the roughness of the metal surface. For example, plasma processing is an example. The hydrophilic treatment is preferably performed on a portion where the temperature is highest. For example, it is desirable that the hydrophilic treatment be performed on the valley portion 14a in contact with the unit cell 11, particularly on the air flow path side. In this way, by performing the hydrophilic treatment, wetting (wetting) of the contact surface between the air electrode side collector 14 and the electrode diffusion layer on the air electrode side of the unit cell 11 is promoted, and the effect of cooling the latent heat of water. Will improve. This also makes it difficult for water to clog the mesh, that is, the opening, thereby further reducing the possibility of water blocking air supply. In addition, since the metal surface essentially has a certain degree of hydrophilicity, the hydrophilic treatment can be omitted.

  The fuel electrode side collector 15 is made of a metal plate material such as an expanded metal having a mesh-like opening with the same dimensions as the air electrode side collector 14, and a corrugated plate having fine ridges 15b formed by pressing. Has been. Then, as in the case of the air electrode side collector 14, the ridges 15 b extend in the vertical direction in FIG. 1 and are arranged so as to completely cut the plate surface in parallel at equal intervals. The cross-sectional shape of the ridges 15b is roughly a rectangular wave-shaped cross-section, and the base side has a slightly flared shape due to press-cutting. The height of the ridges 15b 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 side of the unit cell 11 and the side surface of the separator body 41 is increased. A fuel gas flow path having a predetermined opening area penetrating in the vertical direction is secured. In FIG. 1, an arrow B indicates the flow of hydrogen gas introduced into the unit cell 11 and flowing through the fuel chamber. Moreover, the top of each protrusion 15b is an abutting part that contacts the side surface of the separator body 41, and the plane of the valley 15a between each protrusion 15b is the electrode diffusion layer on the fuel electrode side of the unit cell 11. It is the contact part which contacts. The fuel electrode side collector 15 can be subjected to hydrophilic treatment as necessary.

  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 ridges 14b and 15b of the air electrode side collector 14 and the fuel electrode side collector 15 are in contact with the separator body 41, and are in a state where they 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 of the unit cell 11, and similarly, hydrogen gas is supplied from the fuel chamber to the fuel electrode 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. Permeates the polymer electrolyte membrane. Further, when the air electrode 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 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 and permeates into the fuel chamber through the solid polymer electrolyte membrane in the direction opposite to the hydrogen ions. It is a thing.

  The separator body 41 is connected to the refrigerant inflow pipe 42 and the refrigerant outflow pipe 43, and the refrigerant flowing from the refrigerant inflow pipe 42 is cooled through the refrigerant flow path 45 formed inside the separator body 41. It flows out from the outflow pipe 43. 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 42. Further, the refrigerant flowing out from the refrigerant outflow pipe 43 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. Here, the refrigerant flow path 45 is formed in a meandering shape as shown in FIG. 5 in order to improve the cooling efficiency. As a result, the refrigerant flows through the separator main body 41 as indicated by the arrow C in FIG. 1, so that the flow path length of the refrigerant in the separator main body 41 is increased, and the cooling capacity by a certain amount of refrigerant is improved. Furthermore, since the cooling is not uneven on both the left and right sides of the separator body 41, the unit cell 11 can be uniformly cooled on the left and right. In this embodiment, the refrigerant inflow pipe 42 is connected to the upper part of the separator body 41 and the refrigerant outflow pipe 43 is connected to the lower part. However, the refrigerant inflow pipe 42 is connected to the lower part and the refrigerant outflow pipe 43 is connected to the upper part. May be connected. Thereby, the upper and lower sides of the unit cell 11 can be more uniformly cooled by cooling with the air supplied from the upper side to the lower side of the collectors 14 and 15 and cooling with the refrigerant supplied from the lower part to the upper part of the separator body 41. become. In addition, the shape of the refrigerant flow path 45 may be a shape other than a meandering shape as long as the refrigerant flow path length is long, and may be other shapes such as a spiral shape, for example. .

  In the example shown in FIG. 1, the separator main body 41 is formed by pasting (sticking) two flat metal plates. In this case, a concave groove having a shape as shown in FIG. 5 is formed on the inner surface of one plate by 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 other board | plate material on the surface in which this 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. This ensures contact between the outer surface of the separator body 41 and the tops of the protrusions 14b and 15b of the air electrode side collector 14 and the fuel electrode side collector 15, respectively. In addition, the thermal conductivity and electrical conductivity between the fuel electrode side collector 15 and the fuel electrode side collector 15 can be improved.

  The unit cell 11 is cooled by a separator body 41 that functions as a cooler of 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. In this case, since the trough portions 14a and 15a are in contact with the wide area of the unit cell 11 in the air electrode side collector 14 and the fuel electrode side collector 15, the heat generated in the unit cell 11 is transmitted well. 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.

  Further, since the air electrode side collector 14 and the fuel electrode side collector 15 have a mesh-like opening, the flow of hydrogen gas in the fuel chamber and air in the oxygen chamber is hindered by the air electrode side collector 14 and the fuel electrode side collector 15. There is nothing. That is, the hydrogen gas in the fuel chamber and the air in the oxygen chamber are sufficiently in contact with the electrode diffusion layers on the fuel electrode side and the air 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. Further, since the hydrogen gas in the fuel chamber and the air in the oxygen chamber can also move through the openings of the ridges 14b and 15b, the flow of hydrogen gas in the fuel chamber and the flow of air in the oxygen chamber become smooth. In particular, when water droplets are generated in the oxygen chamber by generated water or water supplied to the air, and the water droplets block the flow path between the adjacent valley portions 14a, the air flows into the ridges 14b. Since it can flow into the adjacent flow path through the opening, the air flow is not hindered. The same applies when water droplets are generated in the fuel chamber due to the reverse diffusion water.

  Further, the air electrode side collector 14 and the fuel electrode side collector 15 function as a cooler of an open cooling system device. That is, air and hydrogen gas cool the unit cell 11 when flowing through the oxygen chamber and the fuel chamber. In this case, the air electrode side collector 14 and the fuel electrode side collector 15 function as cooling fins that are a kind of cooler. To do. Therefore, the cooling capacity by the open cooling system is improved. In particular, when water is supplied to the air, the cooling capacity is improved. In this case, even if water droplets are generated in the oxygen chamber as described above, the air flow is not hindered. There is no decline.

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

  FIG. 6 is a flowchart showing the start-up operation of the fuel cell system according to the first embodiment of the present invention, and FIG. 7 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 by the air supply pump 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 a 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 startup, air is present in the unit cell 11 regardless of whether the air supply system is on or not, so when hydrogen gas is supplied in a state where the solid polymer electrolyte membrane is dry, This is because abnormal combustion may occur. Therefore, even if abnormal heat is generated due to abnormal combustion, water is supplied before supplying the hydrogen gas so that the unit cell 11 is not damaged, and the air electrode of the unit cell 11 is wetted in advance. It is necessary to keep. Thereby, abnormal heat can be converted into water evaporation heat, and further, wetting of the solid polymer electrolyte membrane can be promoted to prevent damage to the unit cell 11 in advance.

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 if the operation of the fuel cell system is continued with the hydrogen exhaust valve 62 closed, N ₂ , 0 ₂ that is transmitted from the air electrode or the influence of the generated water This is because the partial pressure of hydrogen consumed at the fuel electrode gradually decreases, 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 amount of air supply is increased by increasing the number of revolutions of the air supply pump 75, and the temperature of the air electrode that 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 pump 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 fuel cell stack 20 is cooled by a plurality of cooling systems. That is, the refrigerant circulated by the closed cooling system device including the refrigerant supply pipe 53, the refrigerant discharge pipe 71, the refrigerant storage container 52, and the like is formed in the separator main body 41 of the separator unit 12. Each cell module 10 is cooled through the inside. Further, the hydrogen gas and air supplied by an open cooling system device including a device for supplying hydrogen gas and air to the fuel cell stack 20 circulates through the fuel chamber and the oxygen chamber in the cell module 10, and the cell module 10. Cool down. Therefore, the cooling capacity can be controlled in a wide range by turning on or off any one of the plurality of cooling systems. Thereby, the cooling capacity is high, the cooling capacity can be adjusted easily and appropriately, and the temperature of the fuel cell stack 20 is adjusted to an appropriate temperature in a wide temperature range and in an environment where the temperature changes greatly. It is possible to obtain a fuel cell system that can be maintained and output can be increased.

  Further, the refrigerant supplied by the closed cooling system is disposed in parallel in the separator unit 12 in the vicinity of the unit cell 11, and flows through the separator body 41 for partitioning the fuel chamber and the oxygen chamber. The unit cell 11 can be cooled with high efficiency. Furthermore, since the separator unit 12 and the unit cell 11 are connected by a metal air electrode side collector 14 and a fuel electrode side collector 15, the heat transfer rate is high, and the unit cell 11 is cooled with high efficiency by the refrigerant. can do. Furthermore, since the refrigerant flow path 45 formed in the separator main body 41 is meandering and the flow path length of the refrigerant is long, the cooling capacity by the refrigerant can be improved.

  Further, the air electrode side collector 14 and the fuel electrode side collector 15 function as cooling fins and transfer the heat of the unit cell 11 to the hydrogen gas and air in the open cooling system. It can be cooled with high efficiency. In this case, since the air electrode side collector 14 and the fuel electrode side collector 15 have mesh openings, the flow of hydrogen gas in the fuel chamber and air in the oxygen chamber is hindered by the air electrode side collector 14 and the fuel electrode side collector 15. There is nothing to do. Therefore, the pressure loss of hydrogen gas in the fuel chamber and air in the oxygen chamber can be reduced.

  Further, in order to maintain the unit cell 11 of the fuel cell stack 20 in a wet state, when water is sprayed into the air supplied to the oxygen chamber, the latent heat of vaporization of water, etc. Therefore, a further cooling effect can be expected. However, in this case, water droplets may be generated in the oxygen chamber due to excess moisture, but even when the water droplets block the flow path between the adjacent valley portions 14a of the air electrode side collector 14, Since air can flow into the adjacent flow path through the opening of the ridge 14b, the air flow is not hindered. Therefore, the pressure loss of the air in the oxygen chamber can be reduced, and the cooling effect by the sprayed water can be fully expected. In addition, even if the amount of water supplied to the air becomes excessive, the flow of air in the oxygen chamber is not hindered, so the amount of water supplied to the air can be easily controlled. it can. Therefore, the wet state of the unit cell 11 can be easily managed.

  Further, the air electrode side collector 14 and the fuel electrode side collector 15 have corrugated shapes having ridges 14b and 15b, and the tops of the ridges 14b and 15b contact the flat side surface of the separator body 41. The planes of the valleys 14a and 15a between the ridges 14b and 15b are in contact with the electrode diffusion layers of the unit cell 11 on the air electrode side and the fuel electrode side. Therefore, the thermal conductivity and electrical conductivity between the separator body 41 and the air electrode side collector 14 and the fuel electrode side collector 15 can be improved. Thereby, while improving the cooling effect of the unit cell 11 with a refrigerant | coolant, the current collection resistance of the fuel cell stack 20 can be reduced. Furthermore, the separator main body 41 has the refrigerant flow path 45 formed therein, but since the surfaces on both sides are joined at various places, the electrical conductivity between the surfaces on both sides may be improved. Therefore, the current collection resistance of the fuel cell stack 20 can be reduced.

  Furthermore, the separator main body 41 is formed by bonding two flat metal plate materials, and the surfaces on both sides are joined at various places. Therefore, the separator main body 41 is highly rigid and difficult to deform. Therefore, the present invention can be applied to a pressurization system that is pressurized so that the pressure of the air supplied to the oxygen chamber of the fuel cell stack 20 is higher than the atmospheric pressure. Since the separator main body 41 has a simple structure formed by bonding two flat metal plate members, the cost of the separator unit 12 can be reduced.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which 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. 8 is a diagram showing the configuration of the separator body of the fuel cell system according to the second embodiment of the present invention. 8A is a plan view and FIG. 8B is a side view.

  As in the first embodiment, the separator body 41 in the present embodiment is formed by laminating two flat metal plate materials and includes a coolant channel therein. As shown in FIG. 8, a plurality of protrusions 48 are formed on the inner surface of the plate material 47. Then, the other plate member is overlaid on the surface on which the protrusion 48 is formed, and the inner surface of the other plate member is brought into contact with the top of the protrusion 48, whereby the separator main body 41 having the coolant channel can be obtained. . In this case, since the surfaces on both sides of the separator body 41 are coupled by the plurality of protrusions 48, the electrical conductivity between the surfaces on both sides can be improved. Moreover, since the some protrusion 48 exists in the refrigerant | coolant flow path in the said separator main body 41, the heat exchange efficiency of a refrigerant | coolant and the separator main body 41 can improve, and the cooling capability by a refrigerant | coolant can be improved.

  Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st and 2nd embodiment, the description is abbreviate | omitted by providing the same code | symbol. Also, the description of the same operations and effects as those of the first and second embodiments is omitted.

  FIG. 9 is a diagram showing the configuration of the fuel electrode side collector of the fuel cell system according to the third embodiment of the present invention. 9A is a plan view, FIG. 9B is a cross-sectional view taken along the line DD in FIG. 9A, and FIG. 9C is a cross-sectional view taken along the line EE in FIG. 9A. It is.

  In the present embodiment, the fuel electrode side collector 17 as the current collector is made of a metal plate having no opening, and the fine ridges 17d and the valleys formed by pressing are alternately formed to form a concave groove. The corrugated plate has 17a and a concave groove 17b. In addition, if one of the concave groove 17a and the concave groove 17b is a trough, the other corresponds to the back side of the protruding line 17d. The concave grooves 17a and the concave grooves 17b extend in the longitudinal direction of the plate material, that is, in the lateral direction in FIG. 9A, and are arranged so as to completely cut the plate surface in parallel at equal intervals. The surface of the fuel electrode side collector 17 on which the concave groove 17a is formed (the right side in FIG. 9B) is in contact with the electrode diffusion layer on the fuel electrode side of the unit cell 11 and between the unit cells 11. A fuel chamber is formed, and hydrogen gas flows through the concave groove 17a. Further, the surface of the fuel electrode side collector 17 where the concave groove 17b is formed (the left side in FIG. 9B) abuts the side surface of the separator body 41, and the refrigerant flows through the concave groove 17b. In the present embodiment, the separator body 41 does not have the refrigerant flow path 45 inside, and is made of a single plate material. And since the escape groove 17c which connects adjacent concave grooves 17a is formed, even if a part of the concave grooves 17a are blocked by water droplets generated in the fuel chamber, hydrogen gas passes through the escape grooves 17c. Since it can flow into the adjacent groove 17a, the flow of hydrogen gas is not hindered.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them 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 a figure which shows the refrigerant | coolant flow path formed in the separator main body of the fuel cell system in the 1st Embodiment of this invention. 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 figure which shows the structure of the separator main body of the fuel cell system in the 2nd Embodiment of this invention. It is a figure which shows the structure of the fuel electrode side collector of the fuel cell system in the 3rd Embodiment of this invention.

Explanation of symbols

11 Unit cell 12 Separator unit 14 Air electrode side collectors 14a, 15a Valleys 14b, 15b, 17d Convex strips 15, 17 Fuel electrode side collectors 17a, 17b Groove 20 Fuel cell stack 41 Separator body 45 Cooling flow path 48 Projection

Claims (3)

The fuel cell in which the electrolyte layer is sandwiched between the fuel electrode and the oxygen electrode is a fuel cell stack in which the separator unit is sandwiched,
The separator unit includes a plate-shaped separator body for blocking the air and fuel gas supplied to the oxygen electrode supplied before Symbol fuel electrode,
The separator body is a separate member, and is provided on the oxygen electrode side of the separator body, and includes a mesh-like current collector that radiates heat and collects heat generated in the fuel cell,
The separator body has a coolant channel formed therein for cooling the fuel cell,
The current collector is a corrugated plate comprising a metal plate having a mesh-shaped opening, and having a plurality of parallel protrusions formed by pressing the metal plate.
The plane of the valleys between the ridges is in contact with the electrode contact portion to the electrode diffusion layer of the oxygen electrode, the top of the ridges Ri abuts separator abutment der the flat side of the separator body The fuel cell stack is characterized in that the width of the top of the ridge is narrower than the width of the plane of the valley between the ridges . A fuel cell in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode includes a refrigerant flow path for cooling the fuel cell, and a net-like current collector that radiates heat and collects heat generated in the fuel cell. A fuel cell stack stacked with a separator unit in between;
A fuel supply system for supplying fuel gas to the fuel electrode;
An oxidant supply system for supplying air to the oxygen electrode through the current collector;
A cooling system for supplying a refrigerant to the refrigerant flow path,
The separator unit includes a plate-shaped separator body for blocking the air and fuel gas supplied to the oxygen electrode supplied before Symbol fuel electrode,
The separator body is a separate member, and is provided on the oxygen electrode side of the separator body, and includes a mesh-like current collector that radiates heat and collects heat generated in the fuel cell,
The separator body has a coolant channel formed therein for cooling the fuel cell,
The current collector is a corrugated plate comprising a metal plate having a mesh-shaped opening, and having a plurality of parallel protrusions formed by pressing the metal plate.
The plane of the valleys between the ridges is in contact with the electrode contact portion to the electrode diffusion layer of the oxygen electrode, the top of the ridges Ri abuts separator abutment der the flat side of the separator body The fuel cell system is characterized in that the width of the top of the ridge is narrower than the width of the plane of the valley between the ridges . A thermometer for detecting the temperature of the exhaust air discharged from the oxygen electrode;
A controller that increases at least one of the amount of air supplied to the oxygen electrode and the amount of refrigerant supplied to the refrigerant flow path when the temperature of the exhaust air detected by the thermometer is equal to or higher than a predetermined value; The fuel cell system according to claim 2 .

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