JP2005317442A - Starting method of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conduct oxidation reaction with a catalyst in a wide range especially at low temperature and surely conduct warming up of the whole fuel cell in a short time. <P>SOLUTION: A first to fourth oxidant gas communicating holes 30a to 30d, a first to fourth cooling medium communicating holes 32a to 32d, and a first to fourth fuel gas communicating holes 34a to 34d passing through in the stacking direction are formed in a fuel cell 10. Two or more of the first to fourth oxidant gas communicating holes 30a to 30d are set in an oxidant gas supply port, and mixed oxidant gas prepared by mixing fuel gas to the oxidant gas in a low rate is simultaneously supplied from two or more oxidant gas supply ports to an oxidant gas passage 42. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell starting method in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a pair of separators sandwiching the electrolyte membrane / electrode structure are stacked.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. ing. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of fuel cells.

  In this fuel cell, a fuel gas supplied to the anode side electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) is ionized with hydrogen on the electrode catalyst, and the cathode passes through the electrolyte membrane. Move to the side electrode side. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. The cathode side electrode is supplied with an oxidant gas, for example, a gas mainly containing oxygen or air (hereinafter also referred to as an oxygen-containing gas). And oxygen reacts to produce water.

  By the way, in this type of fuel cell, in order to maintain ionic conductivity, it is necessary to appropriately humidify the electrolyte membrane made of the polymer ion exchange membrane. Furthermore, water generated by the reaction is present at the cathode side electrode as described above. For this reason, when starting the fuel cell below freezing point (below the freezing temperature of water), the water in the fuel cell easily freezes, and it is pointed out that the electrochemical reaction is difficult to occur in the fuel cell. Yes.

  Therefore, for example, in Patent Document 1, when a fuel cell is started at a low temperature, heat is generated by supplying a mixed gas of air (oxidant gas) and hydrogen to the oxidant gas flow path of the fuel cell. And a technique for heating the fuel cell is disclosed.

  In Patent Document 2, as shown in FIG. 12, an air supply manifold 2 and an air discharge manifold 3 are provided on both left and right sides of the separator 1, and each supply port 2 a constituting the air supply manifold 2 is provided at each supply port 2 a. The air compressor 5 can communicate with each other via the valves 4. Each discharge port 3 a constituting the air discharge manifold 3 can be freely opened to the atmosphere via a valve 5.

  A gas flow path 7 communicating with the air supply manifold 2 and the air discharge manifold 3 is formed in the surface of the separator 1. The valves 4 and 6 are driven and controlled by a control device 9 having an ECU 8.

  In such a configuration, the control device 9 is provided with valves 4a and 6a for supplying air only to a portion having a small heat dissipation loss at the time of cold start of the fuel cell, that is, the central portion of the gas flow path 7. Open. Accordingly, the air supplied from the air compressor 5 is supplied only to the central part of the gas flow path 7 under the opening action of the valve 4a, and after generating electricity at this central part, it is exhausted under the opening action of the valve 6a. The

  Next, when water freeze occurs in the central portion of the gas flow path 7, gas is supplied to the gas flow path 7 in the adjacent area. The gas supply destination is changed to the flow path 7. Then, after the cell temperature rises by repeating the above operation, air is supplied to the entire surface of the gas flow path 7.

US Pat. No. 6,103,410 (FIG. 1) Japanese Patent Laying-Open No. 2003-346853 (FIG. 1)

  However, in Patent Document 1 described above, in order to supply a mixed gas in which hydrogen is mixed in the air at a rate of 4 vol% or less, preferably 2 vol%, at a low temperature start from a single communication hole to the cathode flow path, An oxidation reaction is locally performed in the catalyst layer in the vicinity of the communication hole. Accordingly, since the temperature rise partially proceeds, it is difficult to uniformly warm the entire fuel cell. Moreover, in the catalyst layer, the oxidation reaction proceeds locally, and there is a problem that the deterioration of the catalyst is concentrated in the oxidation reaction portion.

  On the other hand, in Patent Document 2 described above, partial self-heating is repeatedly performed by selectively supplying air from the plurality of supply ports 2 a of the air supply manifold 2 to the gas flow path 7. However, particularly at the time of starting below freezing point, there is a problem that it takes a considerable time to raise the temperature of the entire fuel cell by self-heating to a temperature at which the fuel cell is not frozen.

  The present invention solves this type of problem, and can perform a wide range of oxidation reactions with a catalyst, particularly at low temperatures, and can warm up the entire fuel cell satisfactorily in a short time. An object of the present invention is to provide a battery starting method.

  The present invention comprises an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a pair of separators sandwiching the electrolyte membrane / electrode structure, and reacts along the power generation surface of the electrode. This is a fuel cell starting method provided with a reaction gas flow path for flowing a gas and a plurality of reaction gas communication holes provided in the stacking direction and communicating with the reaction gas flow path.

  Therefore, a fuel cell is started to generate power by simultaneously supplying a mixed gas obtained by mixing one reactive gas with the other reactive gas at a predetermined ratio from a plurality of reactive gas communication holes to the reactive gas flow path.

  Further, among the plurality of reaction gas communication holes, any two or more may be used as reaction gas supply ports, and the mixed gas may be simultaneously supplied from the two or more reaction gas supply ports to the reaction gas flow path to generate power. It is preferable to start.

  Further, the present invention provides a mixture in which one reaction gas is mixed at a predetermined ratio while sequentially switching an arbitrary reaction gas communication hole as a reaction gas supply port among a plurality of reaction gas communication holes. When the gas is supplied from the reaction gas supply port to the reaction gas channel, power generation of the fuel cell is started.

  Furthermore, the reaction gas flow path is an oxidant gas flow path, and the reaction gas communication hole is an oxidant gas communication hole. A fuel that is the other reaction gas is added to an oxidant gas that is one reaction gas. It is preferable that a mixed gas obtained by mixing gases at a low ratio is supplied to the oxidant gas flow path from an oxidant gas supply port which is a reaction gas supply port.

  The reaction gas flow path is a fuel gas flow path, and the reaction gas communication hole is a fuel gas communication hole, and an oxidant gas, which is the other reaction gas, is supplied to the fuel gas, which is one reaction gas. It is preferable that the mixed gas mixed at a low ratio is supplied to the fuel gas flow path from a fuel gas supply port which is a reaction gas supply port.

  According to the present invention, since the mixed gas is simultaneously supplied to the reaction gas flow path from the plurality of reaction gas communication holes, the region of the oxidation reaction in the catalyst is expanded, and the temperature of the entire fuel cell can be quickly raised. it can. Thereby, in particular, the warm-up time at the time of low-temperature start is effectively shortened, and by employing an oxidation reaction with a catalyst instead of self-heating, start-up below freezing can be performed easily and reliably. In addition, the oxidation reaction in the catalyst does not occur locally, local deterioration of the catalyst can be satisfactorily prevented, and the durability of the catalyst is improved.

  Further, in the present invention, since the mixed gas is supplied to the reaction gas supply port while any reaction gas communication hole is sequentially switched as the reaction gas supply port, the region of the oxidation reaction in the catalyst is effective. Enlarged. Therefore, it is possible to prevent local deterioration of the catalyst and warm up the entire fuel cell uniformly and rapidly.

  FIG. 1 is a schematic configuration diagram of a fuel cell system 12 incorporating a fuel cell 10 for carrying out a starting method according to a first embodiment of the present invention.

  A plurality of fuel cells 10 are stacked in the vertical direction (arrow A direction) to form a fuel cell stack 14. The fuel cell stack 14 includes a cathode-side control unit 16 that supplies and discharges an oxidant gas, for example, an oxygen-containing gas such as air, and an anode-side control unit 18 that supplies and discharges a fuel gas, for example, a hydrogen-containing gas. And a cooling side control unit 20 for supplying and discharging a cooling medium such as pure water or ethylene glycol is mounted.

  As shown in FIG. 2, the fuel cell 10 includes a substantially square electrolyte membrane / electrode structure 24, and substantially square metal first and second separators 26 sandwiching the electrolyte membrane / electrode structure 24, 28. The first and second separators 26 and 28 are integrated with a resin seal having a sealing function and an insulating function.

  A first oxidant gas communication hole 30a for flowing an oxygen-containing gas is connected to one end edge in the arrow B direction of the fuel cell 10 in the direction of arrow A, which is the stacking direction, and a first flow path for flowing a cooling medium. One cooling medium communication hole 32a and a first fuel gas communication hole 34a for flowing a hydrogen-containing gas are sequentially provided in the direction of arrow C.

  A second fuel gas communication hole 34b, a second cooling medium communication hole 32b, and a second oxidant gas communication hole 30b communicate with each other in the arrow A direction at the upper edge of the fuel cell 10 in the arrow C direction. They are sequentially provided in the B direction.

  A third oxidant gas communication hole 30c, a third cooling medium communication hole 32c, and a third fuel gas communication hole 34c communicate with each other in the arrow A direction at the other end edge of the fuel cell 10 in the arrow B direction. They are provided sequentially in the direction of arrow C. The fourth oxidant gas communication hole 30d, the fourth cooling medium communication hole 32d, and the fourth fuel gas communication hole 34d communicate with each other in the arrow A direction at the lower edge of the fuel cell 10 in the arrow C direction. They are sequentially provided in the B direction.

  As shown in FIGS. 2 and 3, the electrolyte membrane / electrode structure 24 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and the solid polymer electrolyte membrane 36 sandwiched therebetween. An anode side electrode 38 and a cathode side electrode 40 are provided. The anode side electrode 38 and the cathode side electrode 40 are composed of a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. Respectively.

  An oxidant gas flow path (reactive gas flow path) 42 that can communicate with the first to fourth oxidant gas communication holes 30a, 30b, 30c, and 30d is formed on the surface 26a of the first separator 26 facing the cathode side electrode 40. Is provided. The oxidant gas flow path 42 is formed by a plurality of embosses 44.

  As shown in FIGS. 2 and 4, a fuel gas flow path capable of communicating with the first to fourth fuel gas communication holes 34 a, 34 b, 34 c and 34 d is provided on the surface 28 a of the second separator 28 facing the anode side electrode 38. (Reactive gas flow path) 46 is provided. The fuel gas passage 46 is formed by a plurality of embosses 48.

  As shown in FIG. 2, a cooling medium flow path 50 is provided on a surface 28 b opposite to the surface 28 a of the second separator 28. The cooling medium flow path 50 is formed by a plurality of embosses 52, and the embosses 52 are set to have a smaller diameter than the embosses 48.

  As shown in FIG. 5, the cathode side control unit 16 includes a compressor 60 for supplying, for example, air as an oxidant gas, and the compressor 60 is connected to the first switching mechanism 64 via a supply pipe 62. The The first switching mechanism 64 is, for example, a rotary type, and is mounted on the supply side of the fuel cell stack 14 and switched via the first actuator 66.

  The first actuator 66 may be a mechanical type, an electric type, an electromagnet type, a pneumatic type, a hydraulic type, or the like. The first switching mechanism 64 is switched and controlled via the first actuator 66 to supply the first actuator 66. The pipe 62 communicates selectively or simultaneously with the first to fourth oxidant gas communication holes 30a to 30d.

  The first switching mechanism 64 uses, for example, first to fourth electromagnetic switching valves (not shown) instead of the rotary type, and supplies the first to fourth oxidant gas communication holes 30a to 30d to the supply pipe. You may comprise so that it may communicate with 62 individually.

  A second switching mechanism 68 is mounted on the discharge side of the fuel cell stack 14 via a second actuator 70 so as to be switchable. Similarly to the first switching mechanism 64 described above, the second switching mechanism 68 can selectively or simultaneously communicate the first to fourth oxidant gas communication holes 30 a to 30 d to the discharge pipe 72.

  The first and second actuators 66 and 70 are driven and controlled by a controller 76 via a computer 74, and a detection signal from a sensor 78 mounted on the fuel cell stack 14 is input to the computer 74. As this sensor 78, for example, a humidity detection sensor or a temperature detection sensor on the inlet side or outlet side of air that is an oxidant gas, a generated water amount detection sensor in the electrode surface, a current density detection sensor, and the like are used. Further, instead of the sensor 78, switching control can be performed at regular intervals by a timer.

  By driving the first and second switching mechanisms 64 and 68, the first to fourth oxidant gas communication holes 30a to 30d are connected to the oxidant gas supply port (reaction gas supply port) and / or the oxidant gas discharge port (reaction gas). Switching operation is performed as a discharge port.

  As shown in FIG. 1, the anode-side control unit 18 is configured in the same manner as the cathode-side control unit 16 described above, and is connected to a fuel gas tank (not shown) and connected to the supply side of the fuel cell stack 14 via a supply pipe 79. And a second switching mechanism 82 connected to the discharge side of the fuel cell stack 14 via a discharge pipe 81. Via the first and second switching mechanisms 80 and 82, the first to fourth fuel gas communication holes 34 a to 34 d can selectively or simultaneously communicate with the supply pipe 79 and the discharge pipe 81.

  The cooling side control unit 20 is configured in the same manner as the cathode side control unit 16 and the anode side control unit 18 described above, and is connected to a cooling medium tank (not shown) and connected to the supply side of the fuel cell stack 14 via a supply pipe 83. And a second switching mechanism 86 connected to the discharge side of the fuel cell stack 14 via a discharge pipe 85. Via the first and second switching mechanisms 84, 86, the first to fourth cooling medium communication holes 32 a to 32 d can be selectively or simultaneously communicated with the supply pipe 83 and the discharge pipe 85.

  The supply pipe 62 constituting the cathode side control unit 16 is provided with a first mixing valve 88a for mixing fuel gas from the anode side control unit 18 in the air at a low rate, and the anode side control unit 18 is connected to the supply side 62. The supply pipe 79 to be configured is provided with a second mixing valve 88b for mixing air from the cathode-side control unit 16 at a low rate in the fuel gas. The fuel gas is mixed in the air at a ratio of 4 vol% or less, preferably 2 vol%.

  The operation of the fuel cell system 12 configured as described above will be described below in relation to the fuel cell starting method according to the first embodiment.

  First, when the fuel cell system 12 is started at a low temperature such as below freezing, for example, the first mixing valve 88a is operated. Therefore, a predetermined amount of fuel gas is supplied to the supply pipe 62 constituting the cathode side control unit 16 via the supply pipe 79 constituting the anode side control unit 18. As shown in FIG. 5, air (oxidant gas) is supplied to the supply pipe 62 through the compressor 60, and fuel gas is mixed in the air by a predetermined ratio, for example, 2 Vol%.

  Therefore, in the cathode side control unit 16, the first switching mechanism 64 is controlled so that the first and second oxidant gas communication holes 30a and 30b are set as the oxidant gas supply ports, while the third and fourth oxidizers are set. The agent gas communication holes 30c and 30d are set as oxidant gas discharge ports.

  Therefore, as shown in FIGS. 2 and 6, the oxidant gas passage 42 has a mixed gas in which fuel gas is mixed into the air from the first and second oxidant gas communication holes 30a and 30b in a predetermined ratio. (Hereinafter also referred to as mixed oxidant gas) is supplied simultaneously. As a result, in the cathode side electrode 40 constituting the electrolyte membrane / electrode structure 24, an oxidation reaction occurs in the catalyst by the fuel gas mixed in the air, and the temperature rise of the cathode side electrode 40 is started. .

  On the other hand, in the anode side control unit 18, the first switching mechanism 80 and the second switching mechanism 82 are operated, and as shown in FIGS. 2 and 7, the first and fourth fuel gas communication holes 34a and 34d are fuel gas. In addition to being set as a supply port, the second and third fuel gas communication holes 34b and 34c are set as fuel gas discharge ports.

  As shown in FIG. 1, when the second mixing valve 88 b is operated, air is supplied to the fuel gas supplied to the fuel cell stack 14 via the supply pipe 79 via the cathode-side controller 16. A mixed gas is obtained by mixing at a predetermined low ratio (hereinafter also referred to as a mixed fuel gas). For this reason, the mixed fuel gas is simultaneously supplied to the fuel gas flow path 46 from the first and fourth fuel gas communication holes 34a and 34d (see FIGS. 2 and 7). Therefore, the anode side electrode 38 constituting the electrolyte membrane / electrode structure 24 causes an oxidation reaction in the catalyst, and the temperature rise of the anode side electrode 38 is started.

  In this case, in the first embodiment, as shown in FIG. 6, the mixed oxidant gas is simultaneously supplied to the oxidant gas flow path 42 from the first and second oxidant gas communication holes 30a and 30b. Therefore, in the cathode side electrode 40, oxidation reaction sites 90a and 90b are generated in the vicinity of the first and second oxidant gas communication holes 30a and 30b, and the cathode side electrode 40 is heated.

  Therefore, compared with the conventional method in which the mixed oxidant gas is supplied from a single oxidant gas communication hole, the area of the catalyst fuel in the cathode side electrode 40 is greatly expanded, and the cathode side electrode 40 is quickly heated. It becomes possible to make it. As a result, the warm-up time is effectively shortened particularly at low temperature starting such as below freezing point, and the low temperature starting can be performed easily and reliably by adopting the oxidation reaction with the catalyst instead of self-heating. The effect is obtained. In addition, there is an advantage that the oxidation reaction in the catalyst does not occur locally, local deterioration of the catalyst can be satisfactorily prevented, and the durability of the catalyst is improved.

  On the other hand, in the anode side electrode 38, as shown in FIG. 7, the mixed fuel gas is simultaneously supplied to the fuel gas passage 46 from the first and fourth fuel gas communication holes 34a, 34d. For this reason, in the anode side electrode 38, an oxidation reaction is caused in the vicinity of the first and fourth fuel gas communication holes 34a and 34d, and fuel portions 92a and 92b are generated. Accordingly, the region of the oxidation reaction at the catalyst of the anode side electrode 38 is expanded, the oxidation reaction at the catalyst is not locally generated, and the effect that the low temperature start can be performed well and quickly is obtained. It is done.

  In the first embodiment, the mixed oxidant gas is simultaneously supplied from the first and second oxidant gas communication holes 30a and 30b during the low temperature start, while the mixed fuel gas is communicated with the first and fourth fuel gas communication. Although it is simultaneously supplied from the holes 34a and 34d, it is not limited to this. For example, mixed oxidant gas and fuel gas, or air and mixed fuel gas may be used.

  Next, a fuel cell starting method according to the second embodiment of the present invention will be described below with reference to FIG.

  In the second embodiment, for example, the first to fourth oxidant gas communication holes 30a to 30d are provided at the first communication position P1, the second communication position P2, the third communication position P3, and the fourth communication position P4. The switching operation is sequentially performed, and the flow direction of the air in the oxidant gas passage 42 is sequentially changed.

  Specifically, in the first communication position P1, as in the first embodiment, the first and second oxidant gas communication holes 30a and 30b are set at the oxidant gas supply position, while the third and third oxidant gas communication holes 30a and 30b are set. Four oxidant gas communication holes 30c and 30d are set as oxidant gas discharge ports. In the second communication position P2, the second and third oxidant gas communication holes 30b and 30c are set as oxidant gas supply ports, while the fourth and first oxidant gas communication holes 30d and 30a are oxidant gas exhausts. It is set at the exit.

  At the third communication position P3, the third and fourth oxidant gas communication holes 30c and 30d are set as oxidant gas supply ports, while the first and second oxidant gas communication holes 30a and 30b are oxidant gas exhaust ports. It is set at the exit. Further, at the fourth communication position P4, the fourth and first oxidant gas communication holes 30d and 30a are set as oxidant gas supply ports, while the second and third oxidant gas communication holes 30b and 30c are oxidant. The gas outlet is set.

  Therefore, at the time of low temperature start, the mixed oxidant gas is supplied to the two oxidizers while the first to fourth oxidant gas communication holes 30a to 30d are sequentially switched to the first to fourth communication positions P1 to P4. The oxidant gas flow path 42 is simultaneously supplied from the gas supply port.

  Thus, in the second embodiment, the mixed oxidant gas is simultaneously supplied from the two oxidant gas supply ports to the oxidant gas flow path 42, and the two oxidant gas supply ports are sequentially provided. It has been switched. For this reason, the region of the oxidation reaction at the catalyst in the cathode side electrode 40 is further expanded, and it is possible to reliably prevent the local occurrence of the oxidation reaction at the catalyst. Therefore, it is possible to warm up the entire fuel cell 10 uniformly and reliably.

  In the second embodiment, the first to fourth oxidant gas communication holes 30a to 30d have been described. However, the same applies to the first to fourth fuel gas communication holes 34a to 34d. Omitted. Similarly, in the third to fifth embodiments described below, detailed description thereof is omitted.

  FIG. 9 is an explanatory diagram of a fuel cell starting method according to the third embodiment of the present invention. In the third embodiment, the first to fourth oxidant gas communication holes 30a to 30d are sequentially switched to the first to fourth communication positions P11 to P14 to be supplied to the oxidant gas flow path 42. The supply direction of the mixed oxidant gas is sequentially changed. That is, at the first communication position P11, the mixed oxidant gas is supplied from the first oxidant gas communication hole 30a to the oxidant gas flow path 42, and is oxidized by the catalyst in the vicinity of the first oxidant gas communication hole 30a. A reaction occurs.

  In the second communication position P12, the mixed oxidant gas is supplied from the second oxidant gas communication hole 30b to the oxidant gas flow path 42, and catalytic fuel is generated in the vicinity of the second oxidant gas communication hole 30b. Further, at the third communication position P13, the mixed oxidant gas is supplied from the third oxidant gas communication hole 30c to the oxidant gas flow path 42, and catalytic fuel is generated in the vicinity of the third oxidant gas communication hole 30c. . Furthermore, at the fourth communication position P14, the mixed oxidant gas is supplied from the fourth oxidant gas communication hole 30d to the oxidant gas flow path 42, and is oxidized by the catalyst near the fourth oxidant gas communication hole 30d. A reaction occurs.

  Thus, in the third embodiment, the oxidant gas supply port is sequentially switched to the first to fourth oxidant gas communication holes 30a to 30d, so that the cathode side electrode 40 is a local catalyst. The oxidation reaction does not occur. Thereby, the region of the oxidation reaction in the catalyst is enlarged over the vicinity of the outer peripheral circular portion of the cathode-side electrode 40, and the entire fuel cell 10 can be warmed up uniformly and reliably, and the first and second embodiments. Similar effects can be obtained.

  FIG. 10 is an exploded perspective view of the main part of the fuel cell 160 for carrying out the operating method according to the fourth embodiment of the present invention.

  The fuel cell 160 includes a substantially disc-shaped electrolyte membrane / electrode structure 162 and substantially disc-shaped metal first and second separators 164 and 166 that sandwich the electrolyte membrane / electrode structure 162. At the outer peripheral edge of the fuel cell 160, the first oxidant gas communication hole 168a, the second oxidant gas communication hole 168b, and the third oxidant gas communication are located outside the anode side electrode 38 and the cathode side electrode 40. A hole 168c, a fourth oxidant gas communication hole 168d, and a fifth oxidant gas communication hole 168e are formed to penetrate in the direction of arrow A with a predetermined angular interval.

  A first fuel gas communication hole 170a and a first cooling medium communication hole 172a are formed between the first and second oxidant gas communication holes 168a and 168b. A second fuel gas communication hole 170b and a second cooling medium communication hole 172b are provided between the second and third oxidant gas communication holes 168b and 168c, and the third and fourth oxidant gas communication holes 168c and 168d are provided. A third fuel gas communication hole 170c and a third cooling medium communication hole 172c are formed therebetween.

  A fourth fuel gas communication hole 170d and a fourth cooling medium communication hole 172d are provided between the fourth oxidant gas communication hole 168d and the fifth oxidant gas communication hole 168e. A fifth fuel gas communication hole 170e and a fifth cooling medium communication hole 172e are formed between the fifth and first oxidant gas communication holes 168e and 168a.

  In the fourth embodiment configured as described above, in the first to fifth oxidant gas communication holes 168a to 168e, for example, the first to third oxidant gas communication holes 168a to 168c serve as oxidant gas supply ports. On the other hand, the fourth and fifth oxidant gas communication holes 168d and 168e are set as the oxidant gas discharge ports.

  In the first to fifth fuel gas communication holes 170a to 170e, for example, the first and second fuel gas communication holes 170a and 170b are set as fuel gas discharge ports, while the third to fifth fuel gas communication holes 170a to 170e are set. 170c to 170e are set as fuel gas supply ports. In the first to fifth cooling medium communication holes 172a to 172e, any one or more cooling medium supply ports are set, while any one or more is set as a cooling medium discharge port.

  In this case, in the fourth embodiment, the first to third oxidant gas communication holes 168a to 168c are set as the oxidant gas supply ports, and the mixed oxidant gas communicates with the first to third oxidant gas communication ports. The holes 168a to 168c are simultaneously supplied to the oxidant gas flow path 42. Therefore, the oxidation reaction with a partial catalyst does not occur in the cathode side electrode 40, the oxidation reaction region with the catalyst is effectively expanded, and the temperature of the entire fuel cell 160 can be raised rapidly. it can.

  Thereby, in 4th Embodiment, the local degradation of a catalyst is prevented effectively, Especially the effect similar to 1st-3rd Embodiment, such as warming-up time at the time of low temperature start being shortened effectively, etc. Is obtained.

  In the fourth embodiment, as in the second embodiment, any two or more of the first to fifth oxidant gas communication holes 168a to 168e are used as the oxidant gas supply ports while sequentially switching, The mixed oxidant gas can be simultaneously supplied from the two or more oxidant gas supply ports to the oxidant gas flow path 42 to generate electric power.

  Furthermore, as in the third embodiment, any one of the first to fifth oxidant gas communication holes 168a to 168e is used as the oxidant gas supply port, and the mixed oxidant gas is changed to one by sequentially switching. It is also possible to perform the activation by supplying the oxidant gas flow path 42 from the oxidant gas supply port.

  FIG. 11 is an exploded perspective view of a main part of a fuel cell 200 for carrying out an operation method according to the fifth embodiment of the present invention.

  The fuel cell 200 includes an electrolyte membrane / electrode structure 202 and substantially square metal first and second separators 204 and 206 that sandwich the electrolyte membrane / electrode structure 202.

  A first oxidant gas communication hole 208a elongated in the direction of arrow C is formed at one end edge of the fuel cell 200 in the arrow B direction, and a first oxidant gas communication hole 208a is formed above and below the first oxidant gas communication hole 208a. A first cooling medium communication hole 210a and a second cooling medium communication hole 210b are provided. A substantially second central portion of the fuel cell 200 in the direction of arrow B is formed with a second oxidant gas communication hole 208b elongated in the direction of arrow C in parallel with the first oxidant gas communication hole 208a.

  A third oxidant gas communication hole 208c that is parallel to the first and second oxidant gas communication holes 208a and 208b and that is long in the arrow C direction is formed at the other end edge of the fuel cell 200 in the arrow B direction. The A third cooling medium communication hole 210c and a fourth cooling medium communication hole 210d are formed above and below the third oxidant gas communication hole 208c. A first fuel gas communication hole 212a and a second fuel gas communication hole 212b are formed at both ends of the fuel cell 200 in the arrow C direction.

  The electrolyte membrane / electrode structure 202 is positioned between the first to third oxidant gas communication holes 208a to 208c, and is provided with anode side electrodes 38a and 38b and cathode side electrodes 40a and 40b.

  The first separator 204 is formed with oxidant gas flow paths 42a and 42b corresponding to the cathode side electrodes 40a and 40b, and the second separator 206 is fuel corresponding to the anode side electrodes 38a and 38b. Gas flow paths 46a and 46b are divided and formed. In the second separator 206, cooling medium flow paths 50a, 50b are dividedly formed on the surface opposite to the fuel gas flow paths 46a, 46b.

  In the fuel cell 200 configured as described above, the first and second oxidant gas communication holes 208a and 208b are set as the oxidant gas supply port, while the third oxidant gas communication hole 208c is the oxidant gas discharge port. Set to Further, the first fuel gas communication hole 212a is set as a fuel gas supply port, and the second fuel gas communication hole 212b is set as a fuel gas discharge port. Further, the first and third cooling medium communication holes 210a and 210c are set as cooling medium supply ports, and the second and fourth cooling medium communication holes 210b and 210d are set as cooling medium discharge ports.

  In this case, in the fifth embodiment, when the fuel cell 200 is started at a low temperature, the mixed oxidant gas is supplied to the first and second oxidant gas communication holes 208a and 208b, and this mixed oxidant gas is the oxidant gas. After being supplied to each of the flow paths 42a and 42b, it is discharged from the third oxidant gas communication hole 208c.

  For this reason, in the cathode side electrodes 40a and 40b, the mixed oxidant gas is supplied to cause an oxidation reaction in the catalyst, and the oxidation reaction in the catalyst can be prevented from being performed locally. As a result, the same effects as those of the first to fourth embodiments can be obtained, in particular, the warm-up time at the time of cold start can be effectively shortened and the durability of the catalyst can be improved.

  The fuel gas supplied to the first fuel gas communication hole 212a moves vertically upward along the anode-side electrodes 38a and 38b, and is then discharged from the second fuel gas communication hole 212b. On the other hand, the cooling medium supplied to the first and fourth cooling medium communication holes 210a and 210d cools the electrolyte membrane / electrode structure 202 while descending along the cooling medium flow paths 50a and 50b, respectively. And the fourth cooling medium communication holes 210b and 210d.

1 is a schematic configuration diagram of a fuel cell system incorporating a fuel cell for carrying out a starting method according to a first embodiment of the present invention. It is a principal part disassembled perspective view of the said fuel cell. It is principal part cross-sectional explanatory drawing of the said fuel cell. It is front explanatory drawing of the 2nd separator which comprises the said fuel cell. It is explanatory drawing of the cathode side control part which comprises the said fuel cell system. It is explanatory drawing when mixed oxidant gas is supplied to an oxidant gas flow path. It is explanatory drawing when mixed fuel gas is supplied to a fuel gas flow path. It is explanatory drawing of the driving | running method which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the driving | running method which concerns on the 3rd Embodiment of this invention. It is a principal part disassembled perspective view of the fuel cell for enforcing the operating method which concerns on the 4th Embodiment of this invention. It is a principal part disassembled perspective view of the fuel cell for enforcing the operating method which concerns on the 5th Embodiment of this invention. It is a schematic explanatory drawing of patent document 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 160, 200 ... Fuel cell 12 ... Fuel cell system 14 ... Fuel cell stack 16 ... Cathode side control part 18 ... Anode side control part 20 ... Cooling side control part 24, 162, 202 ... Electrolyte membrane and electrode structure 26, 28, 164, 166, 204, 206 ... separators 30a-30d, 168a-168e, 208a-208c ... oxidant gas communication holes 32a-32d, 172a-172e, 210a-210d ... cooling medium communication holes 34a-34d, 170a- 170e, 212a, 212b ... fuel gas communication hole 36 ... solid polymer electrolyte membranes 38, 38a, 38b ... anode side electrodes 40, 40a, 40b ... cathode side electrodes 42, 42a, 42b ... oxidant gas flow paths 46, 46a, 46b ... Fuel gas flow path 50, 50a, 50b ... Cooling medium flow path 60 ... Compressor 6 4, 68, 80, 82, 84, 86 ... switching mechanism 88a, 88b ... mixing valve

Claims (5)

An electrolyte membrane / electrode structure provided with electrodes on both sides of the electrolyte membrane and a pair of separators sandwiching the electrolyte membrane / electrode structure are stacked, and a reaction gas is allowed to flow along the power generation surface of the electrode. A fuel cell starting method provided with a reaction gas flow path and a plurality of reaction gas communication holes provided in the stacking direction and communicating with the reaction gas flow path,
A fuel cell, wherein a mixed gas obtained by mixing one reaction gas with the other reaction gas at a predetermined ratio is simultaneously supplied to the reaction gas flow path from the plurality of reaction gas communication holes to start power generation. How to start.   2. The starting method according to claim 1, wherein any two or more of the plurality of reaction gas communication holes are used as a reaction gas supply port, and the mixed gas is switched from the two or more reaction gas supply ports while sequentially switching. A method for starting a fuel cell, characterized in that power generation is started by simultaneously supplying gas paths. An electrolyte membrane / electrode structure provided with electrodes on both sides of the electrolyte membrane and a pair of separators sandwiching the electrolyte membrane / electrode structure are stacked, and a reaction gas is allowed to flow along the power generation surface of the electrode. A fuel cell starting method provided with a reaction gas flow path and a plurality of reaction gas communication holes provided in the stacking direction and communicating with the reaction gas flow path,
Among the plurality of reaction gas communication holes, an arbitrary reaction gas communication hole is used as a reaction gas supply port, and a mixed gas obtained by mixing one reaction gas with the other reaction gas at a predetermined ratio while sequentially switching is used. A method for starting a fuel cell, wherein power generation is started by supplying the reaction gas flow path from a gas supply port. The start method according to any one of claims 1 to 3, wherein the reaction gas channel is an oxidant gas channel, and the reaction gas communication hole is an oxidant gas communication hole,
A mixed gas obtained by mixing the oxidizing gas, which is the one reactive gas, with the fuel gas, which is the other reactive gas, at a low ratio, is supplied from the oxidizing gas supply port, which is the reactive gas supply port, to the oxidizing gas channel. A method for starting a fuel cell, comprising: supplying to a fuel cell. The start method according to any one of claims 1 to 3, wherein the reaction gas channel is a fuel gas channel, and the reaction gas communication hole is a fuel gas communication hole,
A mixed gas in which the fuel gas that is the one reaction gas is mixed with the oxidant gas that is the other reaction gas at a low ratio is supplied to the fuel gas flow path from the fuel gas supply port that is the reaction gas supply port. A starting method for a fuel cell.

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