JP4595304B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system, and more particularly, to a fuel cell system that can supply fuel gas in a short time at startup.

  Conventionally, in a fuel cell using a polymer electrolyte membrane, fuel gas or oxidizing gas is ionized on both sides of the electrolyte membrane, and the ions pass through the electrolyte membrane to cause an electrochemical reaction. If fuel gas and oxidizing gas are present with the electrolyte membrane in between, the electrochemical reaction between the two continues. For this reason, conventionally, in order to stop the operation of the fuel cell, the supply of the fuel gas and the oxidizing gas to the fuel cell is stopped, and a replacement gas such as air is used instead of the fuel gas on the fuel electrode side. Uses a structure that does not cause an electrochemical reaction after sending and stopping.

  And at the time of driving | operation start, the structure which discharges substitution gas outside and starts reaction by sending fuel gas into a fuel chamber is taken.

  On the other hand, in the fuel chamber, a region where the concentration of the fuel gas is particularly denser than the other region and a region where the concentration of the oxidizing gas is particularly denser than the other region coexist, that is, the fuel gas and the oxidizing gas in the same fuel chamber. When the unevenly distributed state occurs, the portion where the fuel gas is unevenly formed forms a local battery, and the portion where the oxidizing gas is unevenly distributed acts to flow a current opposite to that during normal power generation. There is a problem that the deterioration is accelerated.

  In the conventional configuration, the fuel gas is supplied at the start-up with the same gas pressure as the fuel gas supplied during normal operation of the fuel cell. For this reason, when the fuel gas is supplied at the time of startup, the fuel gas and the replacement gas are instantaneously distributed in the fuel chamber. Due to this uneven distribution, there has been a problem that an electrochemical reaction occurs, which causes deterioration of the electrode.

  An object of the present invention is to provide a fuel cell system in which deterioration of an electrode is suppressed.

  The present invention for solving the above problems has the following configuration.

(1) A fuel cell including a fuel chamber provided adjacent to the fuel electrode, an oxygen chamber provided adjacent to the oxygen electrode, and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode ,
Pressure adjusting means for adjusting the supply pressure of the fuel gas supplied to the fuel chamber;
A fuel gas concentration sensor for detecting the concentration of the fuel gas discharged from the fuel chamber;
The fuel in the fuel chamber is passed before a predetermined time during which an electrochemical reaction occurs due to the uneven distribution in the fuel chamber between the replacement gas filled in the fuel chamber and the fuel gas supplied to the fuel chamber. Determining means for determining whether the gas concentration has reached a predetermined value ;
The pressure adjusting means sets the supply pressure of the fuel gas at the start of power generation of the fuel battery cell to be higher than the supply pressure at the time of normal power generation of the fuel battery cell ,
The fuel cell system according to claim 1, wherein when the determination unit determines that the predetermined value is reached within a predetermined time, the fuel gas supply pressure is changed to a supply pressure during normal operation .

( 2 ) A fuel cell comprising: a fuel chamber provided adjacent to the fuel electrode; an oxygen chamber provided adjacent to the oxygen electrode; and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode; ,
A fuel gas concentration sensor for detecting the concentration of the fuel gas discharged from the fuel chamber;
The fuel in the fuel chamber is passed before a predetermined time during which an electrochemical reaction occurs due to the uneven distribution in the fuel chamber between the replacement gas filled in the fuel chamber and the fuel gas supplied to the fuel chamber. A determination means for determining whether the gas concentration has reached a predetermined value;
Pressure adjusting means for adjusting a supply pressure of the fuel gas supplied to the fuel chamber based on the detected fuel gas concentration;
The pressure adjusting means sets the supply pressure of the fuel gas at the start of power generation of the fuel battery cell to be higher than the supply pressure at the time of normal power generation of the fuel battery cell ,
The fuel cell system according to claim 1, wherein when the determination unit determines that the predetermined value is reached within a predetermined time, the fuel gas supply pressure is changed to a supply pressure during normal operation .

( 3 ) having an oxygen concentration sensor for detecting the oxygen concentration of the exhaust gas from the fuel chamber;
When the oxygen concentration of the exhaust gas is equal to or higher than the concentration at which the electrode may be deteriorated due to an electrochemical reaction between the replacement gas and the fuel gas, the determination means issues a warning indicating that the electrode may be deteriorated. The fuel cell system according to (1) or (2) above .

( 4 ) having a potential detection sensor for measuring the local potential of the electrode;
The pressure adjusting means further changes the supply pressure of the fuel gas to the supply pressure during normal operation when the local potential of the unit cell electrode is smaller than the potential at which the electrode may deteriorate. The fuel cell system according to any one of 1) .

( 5 ) a start switch for turning on / off the fuel cell system;
A fuel cell comprising: a fuel chamber provided adjacent to the fuel electrode; an oxygen chamber provided adjacent to the oxygen electrode; and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode;
A timer for measuring a period after the start switch is turned off;
Pressure adjusting means for adjusting the supply pressure of the fuel gas supplied to the fuel chamber,
When the period measured by the timer is longer than a predetermined period and the start switch is turned on after that, the pressure adjusting means determines the fuel gas supply pressure at the start of power generation of the fuel battery cell. The fuel cell system is characterized by being set higher than the supply pressure during normal power generation.

According to the first aspect of the present invention, since the fuel gas at the time of startup is supplied at a pressure higher than the pressure during normal operation , the replacement from the replacement gas to the hydrogen gas is completed immediately . The occurrence of uneven gas distribution is suppressed, and there is no time for reaction between the unevenly distributed gases, so that deterioration of the electrode due to the generation of local current is suppressed. Further, the fuel gas supply time is shortened, and the time until the system is started is shortened.

According to the invention of claim 2 , the fuel gas supplied to the fuel chamber based on the fuel gas concentration detected by the fuel gas concentration sensor for detecting the concentration of the fuel gas discharged from the fuel chamber. By adjusting the supply pressure of the fuel gas, the fuel gas can be efficiently supplied according to the concentration of the fuel gas.
In addition, since the fuel gas at startup is supplied at a pressure higher than the pressure during normal operation , the replacement from the replacement gas to the hydrogen gas is completed immediately, which may cause uneven gas distribution with the replacement gas. Suppressed and there is no time margin for the reaction to occur between the unevenly distributed gases, and the deterioration of the electrode due to the generation of local current is suppressed. Further, the fuel gas supply time is shortened, and the time until the system is started is shortened.

According to the third aspect of the present invention, the apparatus further includes an oxygen gas concentration sensor that detects the concentration of oxygen discharged from the fuel chamber, and when the detected oxygen gas concentration is lower than a predetermined oxygen gas concentration. By switching to the supply pressure during normal operation, it is possible to further suppress the excessive supply of fuel gas and the uneven distribution of gas in the fuel chamber.

According to the invention described in claim 4 , the possibility of uneven gas distribution is determined by detecting the local potential of each fuel chamber.

According to the fifth aspect of the present invention, when the predetermined period has not elapsed since the start switch is turned off, it is expected that the electrode will not be deteriorated due to gas uneven distribution. Supply pressure during normal power generation. Thereby, excessive supply of fuel gas can be suppressed.

  Next, a preferred embodiment of the present invention will be described. This embodiment is a fuel cell system mounted on an electric vehicle. FIG. 1 is a block diagram showing a fuel cell system 1 of the present invention. As shown in FIG. 1, the fuel cell system 1 is roughly composed of a fuel cell stack 100, an air supply system 12, a fuel supply system 10 including a high-pressure hydrogen tank 11 as a hydrogen supply means, and a water supply system 50. The

  The configuration of the fuel cell stack 100 will be described. The fuel cell stack 100 is configured by alternately stacking fuel cell unit cells 15 and fuel cell separators 13. 2 is an overall front view showing the fuel cell separator 13, FIG. 3 is a partial cross-sectional plan view of the fuel cell stack 100 composed of the fuel cell separator 13 (AA cross-sectional view in FIG. 2), and FIG. FIG. 5 is a partial sectional side view (BB sectional view in FIGS. 2 and 3), FIG. 5 is a partial sectional side view of the fuel cell separator 13 (CC sectional view in FIGS. 2 and 3), and FIG. FIG. 3 is an overall rear view of the fuel cell separator 13.

  The separator 13 includes current collecting members 3 and 4 for contacting the electrodes of the unit cell 15 and taking out current to the outside, and frame bodies 8 and 9 that are externally mounted on the peripheral ends of the current collecting members 3 and 4. I have. The current collecting members 3 and 4 are made of metal plates. The constituent metal is a metal having conductivity and corrosion resistance, and examples thereof include stainless steel, nickel alloy, titanium alloy and the like subjected to corrosion-resistant conductive treatment.

  The current collecting member 3 is in contact with the fuel electrode of the unit cell 15, and the current collecting member 4 is in contact with the oxygen electrode. The current collecting member 3 is formed of a rectangular plate material, and a plurality of columnar convex portions 32 are formed on the surface thereof by pressing. The columnar protrusions 32 are arranged at equal intervals vertically and horizontally along the short side and the long side of the plate material. Between the columnar convex portions 32, the hydrogen flow path 301 is formed along the short side (see FIG. 2) by a groove formed between the columnar convex portions 32 arranged along the long side (lateral direction in FIG. 2). The hydrogen flow path 302 is formed by grooves formed between the columnar convex portions 32 arranged in the vertical direction in FIG. The surface of the apex portion of the columnar convex portion 32 is a contact portion 321 with which the fuel electrode contacts. The back side of the columnar convex portion 32 is a hole 33. Holes 35 are formed at both ends of the current collecting member 3, and when the separators 13 are stacked, the holes 35 form a hydrogen supply path.

  The current collecting member 4 is made of a rectangular plate material, and a plurality of convex portions 42 are formed by pressing. The convex portions 42 are continuously formed in a straight line parallel to the short sides of the plate material, and are arranged at equal intervals. A groove is formed between the convex portions 42 to form an air flow path 40 through which air flows. The surface of the apex portion of the convex portion 42 is an abutting portion 421 with which the oxygen electrode contacts. Further, the back side of the convex portion 42 is a groove-like hollow portion, and the cooling flow path 41 is formed by this hollow portion. The air flow path 40 and the cooling flow path 41 reach the end of the plate material, and both ends are provided with openings that open at the end sides of the plate material. Holes 48 are formed at both ends of the current collecting member 4. When the separators 13 are stacked, the holes 48 form a hydrogen supply path.

  The current collecting members 3 and 4 as described above are overlapped and fixed so that the columnar convex portions 32 and the convex portions 42 are on the outside. At this time, the back side surfaces 34 of the hydrogen flow paths 301 and 302 and the back side face 403 of the air flow path 40 are in contact with each other, so that they can be energized with each other. Further, by superimposing the current collecting members 3 and 4, as shown in FIG. 4, a cooling channel 41 is formed, and the hole 33 constitutes a part of the cooling channel 41. As shown in FIGS. 3 and 5, the air flow path 40 is overlapped with the unit cell 15, and a tubular flow path is formed by closing the groove opening 400. A part of the inner wall of 40 is composed of an oxygen electrode. Oxygen and water are supplied from the air flow path 40 to the oxygen electrode of the unit cell 15.

  The opening on one end side of the air flow path 40 is an introduction port 43 through which air and water flow, and the opening at the other end is a discharge port 44 through which air and water flow out. The air flow path 40 and its aggregate from the inlet 43 to the outlet 44 function as an oxygen chamber (air chamber) for supplying oxygen to the solid electrolyte membrane.

  Moreover, the opening part of the one end side of the cooling channel 41 becomes the inflow opening 45 into which air and water flow in, and the opening part of the other end becomes the outflow opening 46 from which air and water flow out. In the above configuration, the air flow paths 40 and the cooling flow paths 41 are alternately arranged in parallel and are adjacent to each other with the side wall 47 interposed therebetween. For this reason, the introduction ports 43 and the inflow opening ports 45 are alternately arranged, and the outlet ports 44 and the outflow opening ports 46 are also arranged alternately. Moreover, since air and water flow along the side wall 47, the side wall 47 also exhibits an action as a cooling fin.

  By arranging the air flow paths 40 and the cooling flow paths 41 alternately and in parallel, the cooling efficiency of the fuel cell is improved and uniform cooling is possible.

  Frame members 8 and 9 are overlaid on the current collecting members 3 and 4, respectively. As shown in FIG. 2, the frame 8 that is stacked on the current collecting member 3 is configured to have the same size as the current collecting member 3, and a window 81 that houses the columnar protrusion 32 is formed at the center. ing. Further, a hole 83 is formed in the vicinity of both end portions at a position that matches the hole 35 of the current collecting member 3, and a plane on the side in contact with the current collecting member 3 is formed between the hole 83 and the window 81. A recess is formed in the upper surface of the substrate, and a hydrogen flow path 84 is provided. In addition, a concave portion whose contour is formed along the window 81 is formed on the plane opposite to the surface that contacts the current collecting member 3, and a storage portion 82 for storing the unit cell 15 is provided. Yes. The fuel chamber 30 is defined by the fuel electrode surface of the unit cell 15 housed in the housing portion 82, the hydrogen flow paths 301 and 302, and the window 81. Thus, the fuel chamber is provided adjacent to the fuel electrode, and the oxygen chamber is provided adjacent to the oxygen electrode.

  The frame body 9 overlaid on the current collecting member 4 is configured to have the same size as the frame body 8, and a window 91 for accommodating the convex portion 42 is formed at the center. Further, in the vicinity of both end portions, holes 93 are formed at positions corresponding to the holes 83 of the frame body 8. Grooves are formed along the pair of opposing long sides of the frame 8 on the surface of the frame 8 on which the current collecting member 4 is overlapped. By overlapping the current collecting members 3 and 4, the air flow passage 94 is formed. , 95 is configured. One end of the air flow passage 94 is connected to an opening 941 formed on the end surface on the long side of the frame body 8, and the other end is connected to the introduction port 43 of the air flow path 40 and the inflow opening 45 of the cooling flow path 41. It is connected.

  The upstream air flow passage 94 has an end inner wall that is a tapered surface 942 so that the cross-sectional area gradually decreases from the opening 941 side to the air flow path 40 side, and is injected from an air manifold 54 described later. It is easy to take in mist water. On the other hand, one end of the downstream air flow passage 95 is connected to the outlet 44 of the air flow path 40 and the inflow opening 45 of the cooling flow path 41, and the other end is formed on the long side end face of the frame 8. Connected to the opening 951. The air flow passage 95 has an end inner wall as a tapered surface 952 so that the cross-sectional area gradually decreases from the opening 951 side toward the air flow path 40 side. Even when the fuel cell stack 100 is tilted, the tapered surface 952 maintains the discharge of water.

  In addition, a concave portion having a contour formed along the window 91 is formed on the plane opposite to the surface of the frame body 9 that contacts the current collecting member 4, and the storage unit in which the unit cell 15 is stored. 92 is provided.

  FIG. 7 is an enlarged cross-sectional view of the unit cell 15. The unit cell 15 includes a solid polymer electrolyte membrane 15a, and an oxygen electrode 15b and a fuel electrode 15c that are oxidant electrodes stacked on both side surfaces of the solid polymer electrolyte membrane 15a, respectively. The membrane 15a is sandwiched between the oxygen electrode 15b and the fuel electrode 15c. The solid polymer electrolyte membrane 15 a is formed in a size that matches the storage portions 82 and 92, and the oxygen electrode 15 b and the fuel electrode 15 c are formed in a size that matches the windows 91 and 81. Since the thickness of the unit cell 15 is extremely thin compared to the thicknesses of the frame bodies 8 and 9 and the current collecting members 3 and 4, the unit cell 15 is shown as an integral member in the drawing.

The inner walls of the air channel 40 and the cooling channel 41 are subjected to hydrophilic treatment. The surface treatment may be performed so that the contact angle between the inner wall surface and water is 40 ° or less, preferably 30 ° or less. As the treatment method, a method of applying a hydrophilic treatment agent to the surface is taken. Examples of the treating agent to be applied include polyacrylamide, polyurethane resin, titanium oxide (TiO ₂ ), and the like.

  The separators 13 are configured by holding the current collecting members 3 and 4 by the frames 8 and 9 configured as described above, and the fuel cell stack 100 is configured by alternately stacking the separators 13 and the unit cells 15. . FIG. 8 is a partial plan view of the fuel cell stack 100. On the upper surface of the fuel cell stack 100, a large number of introduction ports 43 and inflow opening ports 45 are alternately opened, and air flows into the introduction ports 43 and the inflow opening ports 45 from an air manifold 54, as will be described later. The water sprayed from the nozzle 55 flows in at the same time. The side wall 47 is disposed in the air flow path and also functions as a cooling fin.

  The air and water flowing in from the introduction port 43 and the inflow opening 45 cool the current collecting members 3 and 4 by latent heat cooling in the cooling channel 41.

  FIG. 9 is an overall plan view of the fuel cell stack 100. The fuel cell separator 13 configured as described above constitutes a unit 130 (unit body) in which a predetermined number of units are stacked, and the fuel cell stack 100 is configured by stacking a plurality of the units 130. A separator 14 having a shielding plate 16 sandwiched between the current collecting member 3 and the current collecting member 4 is interposed between the unit 130 and the unit 130. The shielding plate 16 includes a hole 161a or 161b having the same shape as the cross-sectional shape of the hydrogen passages 17a and 17b at a position corresponding to either the hydrogen passage 17a or the hydrogen passage 17b. The shielding plate 16 has conductivity and does not hinder the flow of electricity within the fuel cell stack 100.

  On the other hand, when the shielding plate 16 has the holes 161a, the flow of hydrogen gas in the hydrogen passage 17b is blocked by the shielding plate 16. When the shielding plate 16 has the hole 161b, the hydrogen gas flow in the hydrogen passage 17a is blocked by the shielding plate 16. The shielding plate 16 is, in order from the hydrogen gas inflow side to the outflow side, the shielding plate 16 provided with the holes 161b, the shielding plate 16 provided with the holes 161a, and so on. Alternatingly arranged. As described above, by alternately shielding one of the hydrogen passage 17a and the hydrogen passage 17b for each unit 130, the supplied hydrogen gas flows through each fuel chamber 30 in units of units 130. Specifically, in the first unit 130, hydrogen gas flows in each fuel chamber 30 from the hydrogen passage 17a toward the hydrogen passage 17b, and in the next unit 130, from the hydrogen passage 17b toward the hydrogen passage 17a, Hydrogen gas flows in each fuel chamber 30, and in the next unit 130, hydrogen gas flows in each fuel chamber 30 from the hydrogen passage 17a toward the hydrogen passage 17b. The distribution direction changes.

  That is, the fuel cell stack 100 is a unit 130 configured by stacking the unit cells 15 and the separator 13, and is formed in the unit 130 in the stacking direction of the separator 13, and is located on both sides of the fuel chamber 30. Each of the fuel chambers 30 has a pair of hydrogen passages 17a and 17b, and is formed by stacking the units 130. One hydrogen of each unit 130 is interposed between the adjacent units 130. A communication part (hole 161a (or 161b)) communicating between the passages 17a, 17a (or 17b, 17b) and a blocking part (shielding) for blocking hydrogen flow between the other hydrogen passages 17b, 17b (or 17a, 17a) Plate 16), and the communication portion and the blocking portion are sequentially arranged in the direction of the stacking of the stacked units 130, one of the hydrogen passages 17a, 17a (or 7b, 17b) and the other hydrogen passages 17b, 17b (or 17a, 17a), and the flow direction of the hydrogen gas flowing in each fuel chamber 30 between the pair of hydrogen flow paths (17a, 17b) is The unit 130 is alternately changed in the opposite direction.

  As described above, by dividing the fuel cell stack 100 into the plurality of units 130 and flowing the hydrogen gas for each unit, it is possible to prevent a difference in the hydrogen gas flow rate between the units 130. Further, even in the unit unit 130, it is possible to suppress a difference in hydrogen gas flow rate between the fuel chambers 30 constituted by the stacked separators 13 and unit cells 15. Furthermore, since the hydrogen gas supplied to the fuel cell stack 100 repeatedly flows in the unit 130, the chance of contacting the fuel electrode in the fuel chamber 30 increases, and the reaction efficiency is improved.

  The number of the fuel cell separators 13 constituting the unit 130 is such that the cross-sectional area of the hydrogen flow path 302 in each separator 13 (the position of the surface perpendicular to the streamline of the hydrogen gas flowing in the fuel chamber is the smallest). Area: the sum of the areas of part a in FIG. 10 (the sum of the cross-sectional areas of the hydrogen flow path 302 of the separator 13 constituting the unit 130) or the sum of the cross-sectional areas of the hydrogen flow paths 84 (indicated by the bold solid line in FIG. 11) The area of the enclosed portion b)) is determined to be substantially the same as the cross-sectional area of the hydrogen passages 17a and 17b. With such a configuration, the cross-sectional area of the flow path of the hydrogen gas flowing through the fuel cell stack 100 does not vary greatly until the gas flows into the fuel cell stack 100 and then flows out, and each unit constituting the unit 130 is configured. The gas flow can be more uniformly distributed to the fuel chamber 30 of the separator 13.

  For this reason, even when the gas is supplied at the time of starting, the gas (air) filled at the time of starting can be discharged efficiently and replaced with hydrogen gas more uniformly and quickly.

  FIG. 12 is a front view of the fuel cell stack 100. An introduction guide path 18a as a rectifying means is provided in the hydrogen gas inflow portion of the hydrogen passage 17a. In the introduction guide path 18a, the gas introduction port 181a has the same cross-sectional shape as the hydrogen introduction path 202, and the gas outlet port 182a has the same cross-sectional shape as the hydrogen passage 17a. The flow path 183a from the gas inlet 181a to the gas outlet 182a guides the gas flow so that the width of the cross section gradually increases and the gas flow velocity distribution in the cross section of the hydrogen passage 17a becomes uniform. Furthermore, the flow path 183a is provided with a rectifying plate 184a, which is configured to guide hydrogen gas while suppressing pressure loss of the gas flow.

  FIG. 13 is a rear view of the fuel cell stack 100. A lead-out guide path 18 b is provided in the hydrogen gas outflow portion of the fuel cell stack 100. In the lead-out guide path 18b, the gas introduction port 181b has the same cross-sectional shape as the hydrogen passage 17a, and the gas lead-out port 182b has the same cross-sectional shape as the hydrogen lead-out path 203. The flow path 183b from the gas inlet 181b to the gas outlet 182b gradually decreases in cross-sectional width, and the flow path 183a is provided with a rectifying plate 184a, while suppressing pressure loss of the gas flow. The hydrogen gas is guided.

  With the configuration of the fuel cell stack 100 as described above, the pressure loss of the hydrogen gas flowing into the fuel cell stack 100 is suppressed, and the hydrogen gas is uniformly supplied to the fuel chamber 30 of each fuel cell separator 13.

  Next, another configuration shown in FIG. 1 will be described. The air supply system 12 supplies air from the atmosphere to the air flow path 40 and the cooling flow path 41 through the opening 941 of the fuel cell stack 100, and passes the air discharged from the fuel cell stack 100 through the water condenser 51. Exhaust. The air supply path 123 is provided with an air fan 122 as intake means, and sends air from the atmosphere to the air manifold 54 via the filter 121. Air flows from the manifold 54 into the air flow path 40 of the fuel cell stack 100 and supplies oxygen to the air electrode 3. The air discharged from the fuel cell stack 100 is condensed and recovered by the water condenser 51 and discharged into the atmosphere. The temperature discharged from the fuel cell stack 100 is monitored by an exhaust temperature sensor S1. Further, the fuel cell stack 100 is provided with a potential detection sensor S <b> 2 that measures the local potential of the electrode for each unit cell constituting the fuel cell stack 100.

  In this embodiment, a nozzle 55 is disposed in the air manifold 54, and from this, water is injected in a liquid state during intake and mixed with air. Most of the water is collected in a container provided under the fuel cell stack 100 while maintaining a liquid state.

  The fuel supply system 10 sends the hydrogen released from the high-pressure hydrogen tank 11 to the hydrogen passage 17 a of the fuel cell stack 100 through the hydrogen conduction passage 201 and the hydrogen introduction passage 202. From the high-pressure hydrogen tank 11 side to the fuel cell stack 100 side, a hydrogen primary pressure sensor S3, a hydrogen primary pressure regulating valve 21, a hydrogen source solenoid valve 22, a hydrogen secondary pressure adjustable pressure valve 23, A hydrogen supply electromagnetic valve 24 and a hydrogen secondary pressure sensor S4 are provided in this order. The hydrogen pressure on the high-pressure hydrogen tank 11 side is monitored by the hydrogen primary pressure sensor S3.

  The pressure is adjusted to be suitable for supplying to the fuel cell stack 100 by the hydrogen pressure regulating valve 21. When the hydrogen supply electromagnetic valve 22 is opened and closed, the supply of hydrogen to the fuel cell stack 100 is electrically controlled. When the hydrogen gas is not supplied, the electromagnetic valve 22 is closed and the supply of the hydrogen gas is stopped. It can be stopped. Further, the hydrogen gas pressure immediately before being supplied to the fuel cell stack 100 is monitored by the hydrogen secondary pressure sensor S4.

  One end of a hydrogen introduction path 202 is connected to the hydrogen conduction path 201, and the other end is connected to the hydrogen path 17 a of the fuel cell stack 100.

  In the fuel cell stack 100, as shown in FIG. 3, hydrogen gas flows from the hydrogen passage 17a into the hydrogen flow path 84a, and further flows from the hydrogen flow path 84a into the hydrogen flow paths 301 and 302. In the hydrogen passages 301 and 302, hydrogen is supplied to the fuel electrode, and the remaining hydrogen gas flows into the hydrogen passage 17b from the hydrogen circulation passage 84b.

  In the fuel supply system 10, the hydrogen gas discharged from the hydrogen passage 17 b of the fuel cell stack 100 is discharged to the hydrogen outlet passage 203. The hydrogen lead-out path 203 is provided with an oxygen concentration sensor S5, a hydrogen concentration sensor S6, and a pump 25. The pump 25 is driven in a direction in which hydrogen gas is sucked from the fuel cell stack 100. One end of the hydrogen discharge path 204 and one end of the hydrogen return path 205 are connected to the downstream side of the pump 25. The other end of the hydrogen return path 205 is connected to the hydrogen introduction path 202, and a hydrogen circulation path is formed by the hydrogen introduction path 202, the hydrogen lead-out path 203, and the hydrogen return path 205. The hydrogen return path 205 is provided with a check valve 29 so that hydrogen gas supplied from the high-pressure hydrogen tank 11 does not flow directly to the discharge side. The hydrogen discharge path 204 is provided with a check valve 26, a hydrogen discharge electromagnetic valve 27a, and a silencer 28a in this order.

  The oxygen concentration sensor S5 detects the oxygen concentration of the gas discharged from the fuel cell stack 100, and the hydrogen concentration sensor S6 detects the hydrogen concentration of the gas discharged from the fuel cell stack 100.

  Water in the tank 53 is pumped by a water supply pump 61 through a water supply path 56 to a nozzle 55 disposed in the air manifold 54, and is continuously or intermittently ejected from here in the air manifold 54. . This water is sent to the air flow path 40 and the cooling flow path 41 through the opening 941 of the fuel cell stack 100. Here, since the latent heat is taken away from moisture preferentially, evaporation of moisture from the electrolyte membrane 15a on the oxygen electrode 15b side is prevented. Therefore, the electrolyte membrane 15a always maintains a uniform wet state with the generated water without being dried on the oxygen electrode 15b side. Further, the water supplied to the surface of the oxygen electrode 15b takes heat from the oxygen electrode 15b itself and cools it, and the water flowing into the cooling channel 41 also takes heat. Thereby, the temperature of the fuel cell stack 100 can be controlled.

That is, the fuel cell stack 100 can be sufficiently cooled without particularly adding a cooling water system to the fuel cell stack 100. Note that the output of the water supply pump 61 can be controlled in accordance with the temperature of the exhaust air detected by the exhaust temperature sensor S1, and the temperature of the fuel cell stack 100 can be maintained at a desired temperature.
Water in the tank 53 is supplied to the surface of the oxygen electrode 15b from a nozzle 55 disposed in the air manifold 54, and this water is recovered by the water condenser 51, and together with the water stored in the container, a water recovery pump. By 62, it is collected in the tank 53. A check valve 52 is provided between the pump 62 and the tank 53 in order to prevent the backflow of water from the tank 53 to the water recovery pump 62. The amount of water in the tank 53 is detected by a water level sensor S7.

  Further, the fuel cell system 1 is provided with a start switch (not shown) for starting and stopping the fuel cell system by ignition. An ON / OFF switch may be used instead of the ignition key. Further, a period in which the fuel cell system is connected to an external load (not shown) is assumed to be during normal operation.

  In the above-described configuration, in a normal operation state where power is output from the fuel cell system 1, air is supplied from the air fan 122 to the fuel cell stack 100, and at the same time, hydrogen gas is supplied from the fuel supply system 10 to the fuel cell stack 100. To be supplied. In the fuel cell stack 100, the power generation reaction is continued, and electric power and generated water generated by the reaction are generated. Such a power generation reaction is maintained by continuously supplying air to the oxygen electrode and hydrogen gas to the fuel electrode. In such normal operation, in consideration of the consumption efficiency of hydrogen gas, hydrogen gas having a sufficient concentration capable of reacting in the unit cell 15 is supplied, and the supply pressure during normal operation maintains sufficient reaction. It can be set in a range where no waste occurs. If the supply pressure during normal operation is higher than necessary, the supply will be excessive, a large amount of unreacted hydrogen will be discharged, and fuel gas will be wasted. From such a viewpoint, the supply gas pressure of hydrogen gas during normal operation is set to 0.1 megapascals, for example. On the other hand, the supply gas pressure in the case of supplying hydrogen gas at the time of start-up is set higher (for example, 0.2 MPa) than the gas pressure during the normal operation for the purpose of discharging replacement gas and suppressing gas uneven distribution. The time is also set minutely.

  In the present invention, the normal operation state (normal power generation state) refers to a state in which the fuel cell system 1 is connected to an external load and generates power according to the load. In addition, when the fuel cell is started, the period from when the start switch of the fuel cell system is pressed (the ignition key is turned on) until the fuel cell system 1 is connected to an external load is applied.

  Furthermore, when the combustion cell is started, it means that the time when the fuel cell system 1 was turned off last time exceeds the preset value (when the time from off to on is short, this time It does not apply when starting the fuel cell of the invention and is included in normal operation). Further, a timer (not shown) is provided for these times, and the time is calculated by the timer.

  In the fuel cell system 1 described above, each unit is controlled by the control unit. Moreover, the detection value of each sensor S1-S7 is supplied to a control part. Specifically, the supply amount by the water supply pump 61 is controlled by the control unit, and the on / off of the water recovery pump 62, the on / off of the air fan 122, and the on / off of the hydrogen pump 25 are controlled. Further, the control unit performs opening / closing of the hydrogen source solenoid valve 22, opening / closing of the hydrogen supply solenoid valve 24, opening / closing of the hydrogen discharge solenoid valve 27a, and adjustment control of the set pressure of the hydrogen secondary pressure controllable pressure valve (variable regulator) 23. The

  The fuel cell system 1 having the above-described configuration performs the following operation at startup. 14 and 15 are flowcharts showing the control operation of the fuel supply system 10 when the fuel cell system 1 according to the first embodiment is started.

  When an operation for starting activation such as ignition ON is confirmed (step S101), the sensors are turned on (step S103). The detection value of each part of the system can be acquired by the ON operation of the sensors, and it is determined whether the hydrogen primary pressure is larger than the set value based on the detection value supplied from the hydrogen primary pressure sensor S3 (step S105). . The set value is set to 1 megapascal (MPa), for example. If it is equal to or less than the set value, it means that the hydrogen in the high-pressure hydrogen tank 11 is insufficient, and the activation is stopped (step S109). If it is greater than the set value, based on the detection value supplied from the water level sensor S7, it is determined whether the water level in the water tank 53 is equal to or greater than a certain value (step S107). If it is less than a certain value, the ability to cool the fuel cell stack 100 cannot be fully exhibited, so that the activation is stopped (step S109).

  If the water level in the water tank 53 is greater than or equal to a certain value, the water recovery pump 62 is turned on and water recovery is started (step S111). Further, the water supply pump 61 is driven (step S113). Thereby, water is jetted from the nozzle 55 of the air manifold 54. At the same time, the hydrogen source solenoid valve 22 is opened. Next, the air supply fan 122 is driven (step S115). Thereby, supply of air and water to the oxygen electrode of the fuel cell stack 100 is started.

  Next, supply of hydrogen is started, and an operation for discharging oxygen (air) remaining in the fuel chamber 30 of the fuel cell stack 100 is started. The hydrogen discharge electromagnetic valve 27a is opened (step S117). The driving of the hydrogen pump 25 is started (step S119). By step S117 and step S119, the pressure which attracts | sucks hydrogen from the fuel chamber 30 of the fuel cell stack 100 generate | occur | produces, and the inside of the fuel chamber 30 will become a negative pressure.

  Next, the set pressure of the hydrogen secondary pressure controllable pressure valve (variable regulator) 23 is set to 0.2 MPa (step S121), and the hydrogen supply electromagnetic valve 24 is opened (step S123). By this operation, 0.2 MPa of hydrogen gas is supplied into the fuel chamber 30 in a negative pressure. At the same time, the gas (oxygen) remaining in the fuel chamber 30 before starting is pushed out by the supplied hydrogen gas and sucked out by the hydrogen pump 25 and discharged. This state is maintained for 0.5 seconds (step S125), and after 0.5 seconds, the hydrogen concentration of the exhaust gas is 95 based on the detection value obtained by detecting the gas discharged from the fuel cell stack 100 with the hydrogen concentration sensor S6. It is judged whether it is% or more (step S127). If the hydrogen concentration does not reach 95% within 0.5 seconds, the electrode may deteriorate, so the warning lamp is turned on (step S133). The next step S135 is performed. If the hydrogen concentration of the exhaust gas is 95% or more, the fuel chamber 30 is almost filled with hydrogen gas, and it is assumed that there is no uneven distribution of gas, or oxygen gas does not remain enough to generate local current. can do.

  Based on the detection value of the oxygen concentration sensor S5, it is determined whether the oxygen concentration of the exhaust gas is 1% or less (step S129). If the oxygen concentration is 1% or higher, the electrode may be deteriorated, so that a warning lamp is turned on (step S133). The next step S135 is performed. If the oxygen concentration of the exhaust gas is 1% or less, there is almost no oxygen gas remaining in the fuel chamber 30, no gas is unevenly distributed, or there is no oxygen gas left to generate a local current. Can be guessed.

  If the oxygen concentration is 1% or less, it is determined whether the local potentials of all the unit cell electrodes are 1.1 V or less based on the detection value of the potential detection sensor S2 (step S131). Even if there is one unit cell having a local potential greater than 1.1 V, the electrode may be deteriorated, so the warning lamp is turned on (step S133). The next step S135 is performed. By detecting only the hydrogen gas concentration of the exhaust gas, the degree of gas uneven distribution for each fuel chamber cannot be determined. Therefore, the possibility of gas uneven distribution is determined by detecting the local potential for each fuel chamber.

  If it is determined in step S131 that the local potential of the electrode is 1.1 V or less, the hydrogen concentration of the exhaust gas is 95% or more, the oxygen concentration of the exhaust gas is 1% or less, and all This means that the local potential of the electrode is 1.1V or less. In this case, it means that the inside of each fuel chamber 30 is almost uniformly replaced with hydrogen gas, so the set pressure of the hydrogen secondary pressure variable pressure control valve 23 is set to 0. 0 which is the hydrogen supply pressure during normal operation. The pressure is set to 1 MPa (step S135), the hydrogen discharge electromagnetic valve 27a is closed (step S137), and the routine shifts to a normal operation control routine. Steps S121 and S135 constitute a control means, and the control means and the hydrogen secondary pressure controllable pressure valve 23 constitute a pressure adjusting means.

16 and 17 are flowcharts showing the second embodiment. Since the operation from the ignition ON at the time of startup to the step of opening the hydrogen supply electromagnetic valve 24 is the same as that in steps S101 to S123 of the first embodiment, the description is omitted.
After the hydrogen supply electromagnetic valve 24 is opened (step S223), the setting pressure of the hydrogen secondary pressure adjustable pressure valve 23 is changed between 0.1 MPa and 0.2 MPa at intervals of 0.1 seconds. With this change, the hydrogen gas pressure supplied to the fuel cell stack 100 pulsates in a short time.

  This pulsation changes the flow lines of hydrogen gas formed in the fuel chamber 30 and other flow passages. Therefore, the stagnation occurs in the fuel chamber 30 and other flow passages, and the flow velocity is relatively slow. The generation of this portion is suppressed, and the replacement of residual gas with hydrogen gas proceeds uniformly and rapidly. Steps S221 and S237 constitute a control means, and this control means and the hydrogen secondary pressure controllable pressure valve 23 constitute a pressure adjusting means.

  Since the operation after this step, the operation from step S227 to step S239, is the same as the operation from step S125 to step S137 of the first embodiment, description thereof will be omitted.

  Next, the configuration of the fuel cell system according to the third embodiment shown in FIG. 18 will be described. This system is a system according to the first embodiment shown in FIG. 1, in which a startup hydrogen discharge path 206 is connected to the hydrogen outlet path 203 on the upstream side of the hydrogen pump 25. A startup hydrogen discharge solenoid valve 27b and a startup silencer 28b are provided in this order from the upstream side of the startup hydrogen discharge path 206. The start-up hydrogen discharge electromagnetic valve 27b is also controlled to open and close by the control unit, as in the above-described embodiment.

  The other configuration is the same as the configuration of the first embodiment, and a description thereof will be omitted. The startup operation in this embodiment is the same as that of the first embodiment, but after startup, the startup hydrogen discharge electromagnetic valve 27b is opened. Thereafter, the operations from step S121 to step S137 are executed. The start-up hydrogen discharge path 206 has a larger cross-sectional area than the hydrogen lead-out path 203 and is configured such that pressure loss is less likely to occur in the start-up hydrogen discharge path 206 during discharge.

  Next, the structure of the fuel cell system of 4th Embodiment and 5th Embodiment shown by FIG. 19 is demonstrated. In the configuration of this embodiment, a secondary pressure regulating valve 72a (set value is fixed) is provided at the position of the hydrogen secondary pressure adjustable pressure valve 23 in the first embodiment. A circuit is provided in parallel to the hydrogen secondary pressure regulating valve 72a. The circuit has a flow path 71 whose both ends are connected to the upstream side and the downstream side of the hydrogen secondary pressure regulating valve 72a, and a startup hydrogen secondary pressure regulating valve 72b provided in order from the upstream side in the flow path 71. And a start-up hydrogen supply electromagnetic valve 73. The set value of the start-up hydrogen secondary pressure regulating valve 72b is 0.2 MPa, and the set value of the secondary pressure regulating valve 72a is 0.1 MPa. That is, the set value of the secondary pressure regulating valve 72a is the hydrogen supply pressure during normal operation, and the set value of the startup hydrogen secondary pressure regulating valve 72b is set larger than the hydrogen supply pressure during normal operation. Yes. Opening and closing of the hydrogen supply electromagnetic valve 73 at the time of activation is controlled by the control unit. The other configuration is the same as that of the first embodiment, and the description is omitted.

  In the configuration as described above, the startup control operation of the fourth embodiment is shown in the flowcharts shown in FIGS. The operations from ignition on (step S301) to turning on the hydrogen pump 25 (step S319) are the same as the operations of the first embodiment, and thus description thereof is omitted. After turning on the hydrogen pump 25, the startup hydrogen supply electromagnetic valve 73 is opened (step S321), and the hydrogen supply electromagnetic valve 24 is opened (step S323). As a result, the high-pressure hydrogen gas sent from the hydrogen tank 11 flows into the start-up hydrogen secondary pressure regulating valve 72b having a high set value, and the hydrogen secondary pressure becomes 0.2 MPa. Subsequent operations are the same as steps S125 to S133 of the first embodiment, and a description thereof will be omitted.

  When the hydrogen concentration of the exhaust gas is 95% or more, the oxygen concentration of the exhaust gas is 1% or less, and the local potentials of all the electrodes are 1.1 V or less, the hydrogen supply solenoid valve 73 at startup Is closed (step S335). As a result, the inflow of hydrogen gas to the hydrogen secondary pressure regulating valve 72b at the time of startup stops, and the hydrogen gas flows into the secondary pressure regulating valve 72a that is set to the secondary pressure during normal operation. Thereafter, the hydrogen discharge electromagnetic valve 27a is closed (step S337). The start-up hydrogen supply solenoid valve 73 and steps S321 and S335 constitute a switching means.

  The startup control operation of the fifth embodiment is shown in the flowcharts shown in FIGS. The operations from ignition on (step S401) to driving the hydrogen pump 25 (step S419) are the same as those in the first embodiment, and thus the description thereof is omitted. After the hydrogen pump 25 is turned on, the startup hydrogen supply electromagnetic valve 73 is opened (step S321), and further, the hydrogen supply electromagnetic valve 24 is opened (step S323).

  After opening the hydrogen supply electromagnetic valve 24, the startup hydrogen supply electromagnetic valve 73 is repeatedly switched between open and closed at intervals of 0.1 seconds. When opened, the high-pressure hydrogen gas flows into the startup hydrogen secondary pressure regulating valve 72b having a high set value, and the hydrogen secondary pressure becomes 0.2 MPa. When closed, the high-pressure hydrogen gas flows into the hydrogen secondary pressure regulating valve 72a having a low set value, and the hydrogen secondary pressure becomes 0.1 MPa, which is the supply pressure during normal operation. Hydrogen gas having a pressure of 0.2 MPa and hydrogen gas having a pressure of 0.1 MPa are alternately supplied to the fuel chamber 30 at intervals of 0.1 seconds. As described above, the pulsation of the hydrogen gas pressure suppresses the occurrence of gas stagnation in the fuel chamber 30, and the replacement with the hydrogen gas proceeds more uniformly and rapidly. The start-up hydrogen supply solenoid valve 73 and steps S421 and S437 constitute a switching means. Since the operation from step S427 to step S439 is the same as that from step S325 to step S337 in the fourth embodiment, a description thereof will be omitted.

  As described above, by supplying high-pressure hydrogen gas to the fuel chamber 30 at the time of start-up when the replacement gas is present in the fuel chamber 30, high-pressure hydrogen is added to the stagnant replacement gas at the time of stoppage. Gas flows in. Thereby, by rapidly changing from the stagnant state to the flowing state, mixing of the replacement gas and hydrogen gas occurs, and the occurrence of uneven distribution of the replacement gas and hydrogen gas is suppressed. In addition, since hydrogen gas is supplied at a high pressure, the replacement from the replacement gas to the hydrogen gas is completed immediately, so there is no time allowance for occurrence of uneven distribution and reaction between the unevenly distributed gas, This also suppresses the generation of local current. Generation of local current due to uneven gas distribution can be substantially suppressed by completing the replacement with hydrogen gas within 0.7 seconds, preferably within 0.5 seconds. As described above, the waste of hydrogen gas can be reduced by shortening the supply time.

  Further, by changing the supply pressure of the hydrogen gas, a change occurs in the flow line of the gas flow in the fuel chamber 30. This change also suppresses the retention of the gas and makes it difficult to generate the uneven distribution of gas. Can be made.

Whether the fuel cell is activated or not can be determined based on an on / off operation of a start switch (ignition key). For example, if the interval between the time when the start switch was turned off last time and the time when this time the switch was turned on is greater than a set value, high-pressure hydrogen gas is supplied when starting the fuel cell. On the other hand, if the time interval is less than the set value, normal power generation can be assumed.
This specification discloses the following matters.
(1) A fuel cell comprising a fuel chamber provided adjacent to the fuel electrode, an oxygen chamber provided adjacent to the oxygen electrode, and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode ,
Pressure adjusting means for adjusting the supply pressure of the fuel gas supplied to the fuel chamber;
Prepared,
The pressure adjusting means sets the supply pressure of the fuel gas at the time of starting the power generation of the fuel cell higher than the supply pressure of the fuel cell at the time of normal power generation.
Fuel cell system. With this configuration, fuel gas at startup is supplied at a pressure higher than that during normal operation, so that the occurrence of uneven gas distribution with the replacement gas is suppressed, and deterioration of the electrode due to the generation of local current is prevented. It is suppressed. Further, the fuel gas supply time is shortened, and the time until the system is started is shortened.
(2) The fuel cell system according to (1), wherein the pressure adjusting unit includes a modulable pressure valve and a control unit for the tunable pressure valve. With this configuration, the supply pressure of the fuel gas is controlled and changed by the adjustable pressure valve and its control means, so that the number of parts is small and the entire system can be downsized.
(3) Provided with a flow path through which the fuel gas flows when the fuel cell is activated, the pressure adjusting means includes two pressure regulating valves having different supply pressures, an open / close valve provided in the flow path, and the open / close valve The fuel cell system according to (1), further including a switching unit that opens and closes. With this configuration, since the pressure regulating valve used at startup and the real pressure regulating valve used during normal operation are separately provided, the burden on the pressure regulating valve can be reduced and the life of the pressure regulating valve can be extended.
(4) The fuel cell system according to (1), wherein the normal power generation time of the fuel cell is a period in which the fuel cell is connected to an external load. With this configuration, since the supply pressure during the period in which the fuel cell is connected to the external load is set to a pressure lower than the supply pressure at the time of startup, fuel efficiency can be improved.
(5) The fuel cell system according to (1), further including a start switch for turning on / off the fuel cell system, wherein the start time of the fuel cell includes a predetermined period after the start switch is turned on. With this configuration, a start switch for turning on and off the fuel cell system is provided, and within a predetermined period after the start switch is turned on, the supply pressure of the fuel gas is set higher than the supply pressure during normal power generation of the fuel cell. By setting the pressure adjusting means to be set, the time from when the start switch is turned on to the start of normal operation can be shortened.
(6) The fuel cell system according to (5), wherein the time when the fuel cell is started includes a case where the start switch is turned on after a lapse of a predetermined period after the start switch is turned off during the normal power generation. With this configuration, immediately after the start switch is turned off, the fuel gas is uniformly present in the fuel chamber, so that it is not necessary to supply the fuel gas at a high pressure. The supply pressure is increased when the switch is turned on after a lapse of a predetermined period (period in which gas can be unevenly distributed) from the start switch off. Thereby, fuel gas can be used efficiently.
(7) A fuel cell including a fuel chamber provided adjacent to the fuel electrode, an oxygen chamber provided adjacent to the oxygen electrode, and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode ,
A fuel gas concentration sensor for detecting the concentration of the fuel gas discharged from the fuel chamber;
Pressure adjusting means for adjusting a supply pressure of the fuel gas supplied to the fuel chamber based on the detected fuel gas concentration;
The fuel cell system, wherein the pressure adjusting means sets a supply pressure of the fuel gas at the start of power generation of the fuel cell higher than a supply pressure of the fuel cell at the time of normal power generation. With this configuration, the supply pressure of the fuel gas supplied to the fuel chamber is adjusted based on the fuel gas concentration detected by the fuel gas concentration sensor that detects the concentration of the fuel gas discharged from the fuel chamber. Thus, the fuel gas can be efficiently supplied according to the concentration of the fuel gas.
(8) When the fuel gas concentration detected by the fuel gas concentration sensor is higher than a predetermined fuel gas concentration, the pressure adjusting means switches from the supply pressure at the start to the supply pressure at the normal operation (7) The fuel cell system described in 1. With this configuration, when the fuel gas concentration detected by the fuel gas concentration sensor is higher than the predetermined fuel gas concentration, the supply pressure during startup is switched to the supply pressure during normal operation, thereby suppressing excessive fuel gas supply. can do.
(9) The fuel cell system according to (8), wherein the predetermined fuel gas concentration is 95% by weight. With this configuration, when the predetermined fuel gas concentration reaches 95% by weight, switching to the supply pressure during normal operation can suppress excessive fuel gas supply and uneven gas distribution in the fuel chamber.
(10) The apparatus further includes an oxygen gas concentration sensor that detects a concentration of oxygen discharged from the fuel chamber, and the pressure adjusting means has a fuel gas concentration detected by the fuel gas concentration sensor that is higher than a predetermined fuel gas concentration. The fuel cell system according to (7), wherein when the oxygen gas concentration detected by the oxygen concentration sensor is low and lower than a predetermined oxygen gas concentration, the supply pressure at the start is switched to the supply pressure at the normal operation. With this configuration, an oxygen gas concentration sensor for detecting the concentration of oxygen discharged from the fuel chamber is further provided, and further, when the detected oxygen gas concentration is lower than a predetermined oxygen gas concentration, the supply pressure during normal operation is provided. By switching to, excessive fuel gas supply and uneven gas distribution in the fuel chamber can be further suppressed.
(11) The fuel cell system according to (10), wherein the predetermined fuel gas concentration is 95% by weight, and the predetermined oxygen concentration is 1% by weight. With this configuration, when the oxygen concentration falls to 1% by weight, switching to the supply pressure during normal operation can further suppress excessive fuel gas supply and uneven gas distribution in the fuel chamber.
(12) a start switch for turning on and off the fuel cell system;
A fuel cell comprising: a fuel chamber provided adjacent to the fuel electrode; an oxygen chamber provided adjacent to the oxygen electrode; and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode;
A timer for measuring a period after the start switch is turned off;
Pressure adjusting means for adjusting the supply pressure of the fuel gas supplied to the fuel chamber,
When the period measured by the timer is longer than a predetermined period and the start switch is turned on after that, the pressure adjusting means determines the fuel gas supply pressure at the start of power generation of the fuel battery cell. The fuel cell system is characterized by being set higher than the supply pressure during normal power generation. With this configuration, if a predetermined period has not elapsed since the start switch was turned off, it is expected that the electrode will not deteriorate due to the uneven gas distribution. To do. Thereby, excessive supply of fuel gas can be suppressed.

1 is a block diagram showing a fuel cell system 1 of the present invention. It is a whole front view which shows the separator for fuel cells. It is a fragmentary sectional top view (AA sectional view) of the fuel cell stack comprised with the fuel cell separator. It is a partial section side view (BB sectional view) of a fuel cell stack constituted with a fuel cell separator. It is a partial cross section side view (CC sectional view) of a fuel cell separator. 1 is an overall rear view of a fuel cell separator. It is sectional drawing of a unit cell. It is a partial top view of a fuel cell stack. 1 is an overall plan view of a fuel cell stack. It is a partial cross section side view of a fuel cell stack. It is a fragmentary sectional view (DD sectional view) of a fuel cell stack which shows a longitudinal section of a hydrogen passage. 1 is an overall front view of a fuel cell stack. 1 is an overall rear view of a fuel cell stack. It is a flowchart which shows the control operation at the time of start in 1st Embodiment. It is a flowchart which shows the control operation at the time of start in 1st Embodiment. It is a flowchart which shows the control operation at the time of start in 2nd Embodiment. It is a flowchart which shows the control operation at the time of start in 2nd Embodiment. It is a system diagram which shows the structure of 3rd Embodiment. It is a system diagram which shows the structure of 4th, 5th embodiment. It is a flowchart which shows the control operation at the time of starting in 4th Embodiment. It is a flowchart which shows the control operation at the time of starting in 4th Embodiment. It is a flowchart which shows the starting control action in 5th Embodiment. It is a flowchart which shows the starting control action in 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 100 Fuel cell stack 13 Fuel cell separator 130 Unit 15 Unit cell 17a, 17b Hydrogen passage 3 Current collection member 30 Fuel chamber 32 Columnar convex part 301 Hydrogen flow path 302 Hydrogen flow path 4 Current collection member 40 Air flow path 41 Cooling channel 42 Convex portion 43 Inlet port 44 Outlet port 45 Inflow opening port 46 Outflow opening port 8 Frame body 9 Frame body

Claims (5)

A fuel cell comprising: a fuel chamber provided adjacent to the fuel electrode; an oxygen chamber provided adjacent to the oxygen electrode; and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode;
Pressure adjusting means for adjusting the supply pressure of the fuel gas supplied to the fuel chamber;
A fuel gas concentration sensor for detecting the concentration of the fuel gas discharged from the fuel chamber;
The fuel in the fuel chamber is passed before a predetermined time during which an electrochemical reaction occurs due to the uneven distribution in the fuel chamber between the replacement gas filled in the fuel chamber and the fuel gas supplied to the fuel chamber. Determining means for determining whether the gas concentration has reached a predetermined value ;
The pressure adjusting means sets the supply pressure of the fuel gas at the start of power generation of the fuel battery cell to be higher than the supply pressure at the time of normal power generation of the fuel battery cell ,
The fuel cell system according to claim 1, wherein when the determination unit determines that the predetermined value is reached within a predetermined time, the fuel gas supply pressure is changed to a supply pressure during normal operation . A fuel cell comprising: a fuel chamber provided adjacent to the fuel electrode; an oxygen chamber provided adjacent to the oxygen electrode; and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode;
A fuel gas concentration sensor for detecting the concentration of the fuel gas discharged from the fuel chamber;
The fuel in the fuel chamber is passed before a predetermined time during which an electrochemical reaction occurs due to the uneven distribution in the fuel chamber between the replacement gas filled in the fuel chamber and the fuel gas supplied to the fuel chamber. A determination means for determining whether the gas concentration has reached a predetermined value;
Pressure adjusting means for adjusting a supply pressure of the fuel gas supplied to the fuel chamber based on the detected fuel gas concentration;
The pressure adjusting means sets the supply pressure of the fuel gas at the start of power generation of the fuel battery cell to be higher than the supply pressure at the time of normal power generation of the fuel battery cell ,
The fuel cell system according to claim 1, wherein when the determination unit determines that the predetermined value is reached within a predetermined time, the fuel gas supply pressure is changed to a supply pressure during normal operation . An oxygen gas concentration sensor for detecting the concentration of oxygen discharged from the fuel chamber is further provided, and the pressure adjusting means is configured such that the fuel gas concentration detected by the fuel gas concentration sensor is higher than a predetermined fuel gas concentration. 3. The fuel cell system according to claim 1 , wherein when the oxygen gas concentration detected by the concentration sensor is lower than a predetermined oxygen gas concentration, the supply pressure at the time of starting is switched to the supply pressure at the time of normal operation. Having a potential detection sensor for measuring the local potential of the electrode;
The pressure adjusting means further changes the supply pressure of the fuel gas to a supply pressure during normal operation when the local potential of the unit cell electrode is smaller than a potential at which the electrode may deteriorate. the fuel cell system according to one. A start switch for turning on and off the fuel cell system;
A fuel cell comprising: a fuel chamber provided adjacent to the fuel electrode; an oxygen chamber provided adjacent to the oxygen electrode; and an electrolyte membrane sandwiched between the fuel electrode and the oxygen electrode;
A timer for measuring a period after the start switch is turned off;
Pressure adjusting means for adjusting the supply pressure of the fuel gas supplied to the fuel chamber,
When the period measured by the timer is longer than a predetermined period and the start switch is turned on after that, the pressure adjusting means determines the fuel gas supply pressure at the start of power generation of the fuel battery cell. The fuel cell system is characterized by being set higher than the supply pressure during normal power generation.

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