JP2005216519A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a pressure-adjusting control of a fuel gas supplied to a fuel cell by a simple system constitution. <P>SOLUTION: The fuel cell system (10) is provided with: a high-pressure regulator (A6) to adjust the pressure of the fuel gas supplied to the fuel cell (20) at a high pressure, a low-pressure regulator (A7) to adjust the pressure of the fuel cell at a low pressure; a reaction gas supply passage (31) to include branch/junction passages (31a, 31b) to connect these regulators (A6, A7) respectively in parallel; a shut-off valve (A2) to be connected to the high-pressure regulator (A6) in series on the downstream side than the branch/junction passages (31a, 31b) and on the upstream side than the junction (B2); and a control part (60) to adjust the supply pressure of the fuel gas by open-close controlling of the shut-off valve (A2). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system provided with a plurality of regulators for regulating a reaction gas supplied to a fuel cell.

Since the flow rate of the fuel gas supplied to the fuel cell varies in a wide range from a small flow rate to a large flow rate depending on the electric power load, it is difficult to precisely perform such a wide range pressure regulation control with a single pressure regulating valve. . Japanese Patent Application Laid-Open No. 2002-231277 proposes a fuel cell system that enables pressure regulation control with a wide dynamic range by combining a plurality of pressure regulation valves having different flow rate-pressure control characteristics. In this fuel cell system, when the target fuel gas flow calculated based on the required load of the fuel cell is small, the fuel gas is regulated by the low flow type first pressure regulating valve, and when the target fuel gas flow is large The fuel gas is regulated by a high flow type second pressure regulating valve. Furthermore, by providing a shut-off valve downstream of the second pressure regulating valve, the amount of gas leakage when the second pressure regulating valve is closed is reduced, and pressure regulation control of a minimum flow rate by the first pressure regulating valve is enabled. A configuration is also disclosed.
JP 2002-231277 A

  However, in order to regulate the supply pressure of the fuel gas, adjusting the valve opening degree of the plurality of pressure regulating valves and further performing the opening / closing control of the shut-off valve, the system configuration of the electric system that controls these valve mechanisms is It becomes complicated.

  Accordingly, an object of the present invention is to propose a fuel cell system for realizing pressure regulation control of a reaction gas supplied to the fuel cell with a simple system configuration.

  In order to solve the above problems, a fuel cell system according to the present invention includes a plurality of regulators set to different adjustment pressures in order to regulate the pressure of a reaction gas supplied to the fuel cell, and a plurality of regulators in parallel. The branch / combined flow branches for each of the single or multiple regulators except for the reaction gas supply passage including the multiple branch / combined flow channels to be connected and the regulator with the lowest adjustment pressure among the multiple regulators. The single or multiple shut-off valves connected in series and the single or plural shut-off valves are controlled to open and close at the downstream side of the branching point and the upstream side of the junction where the branching / merging passages merge. And a controller that regulates the supply pressure of the reaction gas supplied to the fuel cell. By performing open / close control (on / off control) of the shut-off valve connected in series with the regulator, switching control of the regulator can be performed with a simple system configuration.

  The shut-off valve connected in series with the regulator is preferably arranged on the upstream side of the regulator. Since the pressure on the upstream side of the high-pressure regulator is higher than that on the downstream side, the mass flow rate of the reaction gas is reduced, and the pressure loss due to the shutoff valve can be reduced. In other words, by disposing the shut-off valve upstream of the high-pressure regulator, the shut-off valve can be designed to have a low flow rate, and downsizing can be realized.

  A fuel cell system according to the present invention includes a plurality of regulators for adjusting the pressure of a reaction gas supplied to a fuel cell according to a signal pressure, and a reaction including a plurality of branching / combining passages each connecting the plurality of regulators in parallel. By supplying signal pressure to each of the single or multiple regulators, excluding the regulator that has the lowest adjustment pressure among the multiple supply regulators, one of the multiple regulators can be Signal pressure supply means for adjusting the supply pressure of the reaction gas to be operated and supplied to the fuel cell. Such a configuration eliminates the need for a shut-off valve, thereby simplifying the system configuration.

  ADVANTAGE OF THE INVENTION According to this invention, switching control of a regulator can be enabled by a simple system structure by carrying out open / close control of the cutoff valve connected in series with the regulator. Moreover, since the pressure on the upstream side of the high-pressure regulator is higher than that on the downstream side, the mass flow rate of the reaction gas is reduced, and the pressure loss due to the shutoff valve can be reduced. In other words, by disposing the shut-off valve upstream of the high-pressure regulator, the shut-off valve can be designed to have a low flow rate, and downsizing can be realized. In addition, the use of a regulator that regulates the reaction gas according to the signal pressure eliminates the need for a shut-off valve, thereby further simplifying the system configuration.

Embodiment 1 of the Invention
FIG. 1 shows a system configuration centering on a reaction gas supply system of a fuel cell system 10 according to the first embodiment of the present invention. The fuel cell system 10 is configured as a power generation device that is mounted on a fuel cell electric vehicle and generates power, and includes a fuel cell (cell stack) 20 that generates power by receiving supply of a reaction gas (fuel gas, oxidizing gas). I have. The fuel cell 20 includes a membrane / electrode assembly 24 in which an anode electrode 22 and a cathode electrode 23 are formed on both surfaces of a polymer electrolyte membrane 21 made of a fluorine-based resin or the like and made of a proton conductive ion exchange membrane or the like by screen printing or the like. It has. Both surfaces of the membrane / electrode assembly 24 are sandwiched by a ribbed separator (not shown), and a grooved anode gas channel 25 and cathode gas channel 26 are formed between the separator and the anode electrode 22 and cathode electrode 23, respectively. .

  For convenience of explanation, the structure of a single cell including the membrane / electrode assembly 24, the anode gas channel 25, and the cathode gas channel 26 is schematically shown. It has a stack structure in which a plurality of single cells are connected in series.

  In the fuel gas supply system of the fuel cell system 10, a fuel gas supply path (reaction gas supply path) 31 for supplying fuel gas to the anode gas channel 25 and hydrogen off-gas exhausted from the anode gas channel 25 are supplied as fuel gas. A circulation flow path 32 for refluxing the supply path 31 is provided. The fuel gas supply path 31 includes a shutoff valve A1 that shuts off the fuel gas supply from the high-pressure hydrogen tank 54, a pressure regulator 70 that adjusts the pressure of the fuel gas, and a shutoff valve that shuts off the inflow of fuel gas to the anode inlet. A3 is disposed. The circulation channel 32 is provided with a shutoff valve A4 for blocking outflow of hydrogen offgas from the anode outlet and a hydrogen circulation pump 55 for circulating the hydrogen offgas. The hydrogen circulation pump 55 is configured as an electric pump driven by the motor M 1, and pressurizes the hydrogen off-gas that has undergone pressure loss in the process of passing through the anode gas channel 25 to an appropriate gas pressure, Reflux. The circulation flow path 32 is branched with an exhaust flow path 33 for purging a part of the hydrogen off gas from the circulation flow path 32 to the outside of the vehicle when the concentration of components other than hydrogen contained in the circulation hydrogen becomes high. The hydrogen off-gas purge process is performed by opening and closing a shutoff valve (purge valve) A5 disposed in the exhaust passage 33. The hydrogen off-gas flowing through the exhaust passage 33 is diluted by the diluter 56 and exhausted outside the system.

  On the other hand, the oxidizing gas supply system of the fuel cell system 10 includes an oxidizing gas supply path 41 for supplying oxidizing gas to the cathode gas channel 26 and an oxygen off-gas flow for exhausting cathode off-gas exhausted from the cathode gas channel 26. A path 42 is piped. The air taken in from the atmosphere through the air filter 51 is pressurized by the air compressor 52 driven by the motor M2, and then moderately overhumidified by the humidifier 53, and passes through the oxidizing gas supply path 41. It flows into the cathode gas channel 26. In the humidifier 53, moisture is exchanged between the cathode off-gas that has become highly moistened by the generated water generated by the cell reaction of the fuel cell 20, and the low-humidity oxidizing gas taken from the atmosphere. The back pressure of the cathode gas channel 26 is regulated to a substantially constant pressure by the pressure regulating valve C1. The oxygen off-gas exhausted from the cathode gas channel 26 flows through the oxygen off-gas flow path 42 and is introduced into the diluter 56. After diluting the hydrogen off-gas, the oxygen off-gas is exhausted outside the system.

  The pressure adjusting unit 70 is set to have a high pressure regulator A6 that is set to supply high pressure fuel gas in a high load to medium load range, and is set to supply low pressure fuel gas in a medium load range to low load range. The low-pressure regulator A7, a plurality of branching / combining passages 31a and 31b that connect these regulators A6 and A7 in parallel, and a shutoff valve A2 connected in series to the high-pressure regulator A6. The branching / merging passages 31a and 31b are gas passages that bifurcate from the fuel gas supply passage 31 at the branching point B1 and further join at the joining point B2. In the above configuration, when the shutoff valve A2 is closed, the fuel gas passes through only the low pressure regulator A7 and is adjusted to a low pressure, and then supplied to the fuel cell 20. On the other hand, when the shutoff valve A2 is opened, the fuel gas passes through only the high pressure regulator A6 and is adjusted to a high pressure, and then supplied to the fuel cell 20. At this time, since the secondary side pressure of the high pressure regulator A6 and the secondary side pressure of the low pressure regulator A7 become the same pressure, the low pressure regulator A7 blocks the passage of the fuel gas by the self-sealing function. Due to this self-sealing function, the low-pressure regulator A7 does not have to be provided with a shut-off valve. In this way, switching control between the high pressure regulator A6 and the low pressure regulator A7 can be realized only by opening / closing the shutoff valve A2 (on / off control).

  The arrangement position of the shut-off valve A2 is not particularly limited as long as it is downstream of the branch point B1 and upstream of the junction B2, but is not particularly limited. A position upstream of A6 is desirable. Since the pressure on the upstream side (input port) of the high pressure regulator A6 is higher than that on the downstream side (output port), the mass flow rate is reduced by Bernoulli's theorem, and the pressure loss due to the shutoff valve A2 can be reduced. That is, by providing the shutoff valve A2 upstream of the high pressure regulator A6, the shutoff valve A2 can be designed to have a low flow rate, and downsizing can be realized. Further, as the shutoff valve A2, an on / off valve is suitable, but a valve that can linearly adjust the valve opening degree, such as a linear valve, may be used. Further, as the regulators A6 and A7, mechanical regulators are suitable for simplifying the system configuration. As the shutoff valves A1 to A5, for example, electromagnetic valves are suitable.

  The control unit 60 drives the motors M1 and M2 in accordance with the operating state of the fuel cell 20 to control the rotation speeds of the air compressor 52 and the hydrogen circulation pump 55, and outputs an open / close signal to the shutoff valves A1 to A5 to open and close it. Take control. The fuel gas supply system is provided with pressure sensors P1 to P4 for measuring the gas pressure of each part, and the pressure values output from the pressure sensors P1 to P4 are input to the control unit 60. Yes. Here, the pressure sensor P1 is the gas pressure near the outlet of the shutoff valve A1, the pressure sensor P2 is the gas pressure near the anode inlet, the pressure sensor P3 is the gas pressure upstream of the hydrogen circulation pump 55, and the pressure sensor P4 is The gas pressure on the downstream side of the hydrogen circulation pump 55 is measured.

  Next, switching control of the regulators A6 and A7 will be described in association with the operating state of the fuel cell 20 with reference to FIGS. The control routine shown in these drawings is executed by the control unit 60. First, it is checked whether there is a system activation request (step S1). If there is no system activation request (step S1; NO), the process jumps to step S11. On the other hand, when there is a system activation request (step S1; YES), all of the shutoff valves A1 to A4 are opened, and the shutoff valve A5 is closed, and fuel gas supply to the fuel cell 20 is started. By opening the shutoff valve A2, the high pressure regulator A6 is operated, and the fuel gas supply pressure is increased, thereby shortening the system startup time.

  Next, it is checked whether or not each pressure value output from the pressure sensors P2 to P4 installed in the hydrogen circulation system is equal to or higher than the pressure value Pk1 (step S3). As the pressure value Pk1, it is desirable to select a gas pressure that allows hydrogen leakage determination of the fuel gas supply system. If the fuel gas supplied to the hydrogen circulation system has been supplied to a pressure value Pk1 or more (step S3; YES), the shutoff valves A1 to A5 are closed and a hydrogen leak determination is performed (step S4). In this hydrogen leakage determination, it is checked whether or not the change margins ΔP1 to ΔP4 per unit time of the pressure values output from the pressure sensors P1 to P4 exceed the respective reference values Pc1 to Pc4 (step S5). If none of the change allowances ΔP1 to ΔP4 exceeds the respective reference values Pc1 to Pc4 (step S5; NO), no hydrogen leakage occurs, and the process jumps to step S11.

  On the other hand, if any of the change allowances ΔP1 to ΔP4 exceeds the respective reference values Pc1 to Pc4 (step S5; YES), there is a possibility that hydrogen leakage has occurred, so the shutoff valves A1 to A4 are opened. While all the valves are opened, the shutoff valve A5 is closed (step S6), and the gas pressure in the fuel gas supply system is further increased to perform highly accurate hydrogen leak determination. Next, it is checked whether or not each pressure value output from the pressure sensors P2 to P4 installed in the hydrogen circulation system is equal to or higher than the pressure value Pk2 (step S7). As the pressure value Pk2, it is desirable to select a gas pressure (a gas pressure equal to or higher than Pk1) to such a level that minute hydrogen leakage of the fuel gas supply system can be performed with high accuracy.

  If the fuel gas supplied to the hydrogen circulation system has been supplied to the pressure value Pk2 or more (step S7; YES), the shutoff valves A1 to A5 are closed to determine hydrogen leakage (step S8). In this hydrogen leakage determination, it is checked whether or not the change margins ΔP1 to ΔP4 per unit time of the pressure values output from the pressure sensors P1 to P4 exceed the respective reference values Pd1 to Pd4 (step S9). If none of the change allowances ΔP1 to ΔP4 exceeds the respective reference values Pd1 to Pd4 (step S9; NO), no hydrogen leakage occurs, and the process jumps to step S11. On the other hand, if any of the change allowances ΔP1 to ΔP4 exceeds the respective reference values Pd1 to Pd4 (step S9; YES), it can be determined that hydrogen leakage has occurred, and thus the system is stopped abnormally (step S9). S10). When the system is abnormally stopped, the shutoff valves A1 to A5 are closed and the supply of fuel gas is stopped.

  When it is determined that there is no abnormality in the above-described hydrogen leakage determination, it is checked whether or not the system is in a travelable state (step S11). If it is determined that there is an abnormality in the system and the vehicle is not ready to travel (step S11; NO), an abnormal system stop is performed (step S10). On the other hand, if it is determined that there is no abnormality in the system and the vehicle is ready to travel (step S11; YES), the shut-off valves A1, A3, A4 are opened and the shut-off valve A2 is closed (step S12). The regulator A7 is operated to supply low-pressure fuel gas to the fuel cell 20. Next, the required load is obtained from the accelerator opening, the vehicle speed, etc. (step S13), the required current is calculated from the IV characteristics of the fuel cell 20, and the target rotational speed of the air compressor 52 is taken into account after taking into account the stoichiometric value, etc. The target rotation speed of the hydrogen circulation pump 55 and the target pressure of the anode inlet pressure are respectively calculated based on a map or the like (steps S14, S15, S16).

  Here, when the pressure value measured by the pressure sensor P2 is equal to or higher than the target pressure value (step S17; YES), the supply pressure of the fuel gas is increased, so the shutoff valve A2 is closed (step S1). S18), the low pressure regulator A7 is operated to supply the low pressure fuel gas. On the other hand, when the pressure value measured by the pressure sensor P2 is less than the target pressure value (step S17; NO), the supply pressure of the fuel gas is low, so the shutoff valve A2 is opened (step S19). ), The high pressure regulator A6 is operated to supply the high pressure fuel gas. Thus, the switching control of the regulators A6 and A7 is performed through the opening / closing control of the shutoff valve A2, and the supply pressure of the fuel gas is made to coincide with the target pressure.

  If the battery operation is continued, the amount of impurities such as nitrogen and moisture contained in the anode off-gas circulating through the hydrogen circulation system increases. Therefore, the shutoff valve A5 is opened and closed to exhaust a part of the anode off-gas outside the system (step S20). ). As the battery temperature is lower or the power load is higher, impurities increase, so the open time of the shutoff valve A5 is lengthened and the open / close frequency is increased. Next, in order to adjust the inter-electrode differential pressure, the cathode inlet pressure PA is estimated and calculated (step S21). Since the back pressure at the cathode outlet is adjusted to a substantially constant pressure by the pressure regulating valve C1, the cathode inlet pressure PA can be calculated by calculating the pressure loss in addition to the oxidizing gas flow rate determined from the power load. Next, the inter-electrode differential pressure Pe = P2-PA is calculated (step S22). If the inter-electrode differential pressure Pe is equal to or greater than the threshold value Pt1 (step S23; YES), the fuel gas pressure is greater than the oxidizing gas pressure. Therefore, the shutoff valve A2 is closed (step S24), and the fuel gas pressure is decreased by operating the low pressure regulator A7. On the other hand, when the inter-electrode differential pressure Pe is equal to or less than the threshold value −Pt2 (step S25; YES), since the oxidizing gas pressure is larger than the fuel gas pressure, the shutoff valve A2 is opened (step S26). Then, the high pressure regulator A6 is operated to increase the fuel gas pressure. If the inter-electrode differential pressure Pe is adjusted by adjusting the oxidizing gas pressure, the IV characteristics of the fuel cell 20 may deteriorate. Therefore, the inter-electrode differential pressure Pe can be adjusted by adjusting the fuel gas pressure. It is desirable to do.

  When the power generation time is lengthened, condensed water accumulates in the gas channels 25 and 26, and the effective electrode area of the cell is reduced, so that the reaction gas may not be supplied uniformly to each cell. In such a situation, voltage distribution occurs between the cells, and the cell having the lowest voltage may be stepped down to 0 V or less and overdischarged. If an electric current continues to flow in an overdischarged state, the polymer electrolyte membrane 21 may be damaged. Therefore, it is necessary to drain appropriately. Therefore, the integrated value IT of the generated current is calculated (step S27), and if the current integrated value IT is less than the threshold value IW and the cell voltage is not less than the threshold value V1 (step S28; NO), there is a risk of flooding. Since there is no waste water treatment, the process jumps to step S39. On the other hand, if the current integrated value IT is equal to or greater than the threshold value IW or the cell voltage is equal to or less than the threshold value V1 (step S28; YES), there is a risk of flooding. Causes pressure fluctuations and promotes drainage.

  In order to cause the pressure fluctuation in the gas channels 25 and 26, first, the shutoff valve A2 is opened (step S29), and the high pressure regulator A6 is operated to increase the fuel gas pressure in the anode gas channel 25. Next, the current integrated value IT is cleared to zero (step S30). When the elapsed time from the zero clear point of the current integrated value IT has passed the predetermined time t1 and the cell voltage is equal to or higher than the threshold value V2 (step 31; YES), the cell voltage is recovering, so that The valve A2 is closed (step S32), and the low pressure regulator A7 is operated to lower the fuel gas pressure in the anode gas channel 25. Further, the amount of power generation is increased to increase the consumption of fuel gas (step S33), and the shutoff valve A5 is opened to exhaust the anode off gas outside the system (step 34), thereby further reducing the fuel gas pressure. By increasing the pressure reduction speed in this way, the pulsation effect is increased, and the drainage of moisture stored in the gas channels 25 and 26 is promoted. As the amount of anode off gas exhausted increases, the number of revolutions of the air compressor 52 is increased (step S35), and the flow rate of diluted air introduced into the diluter 56 is increased to dilute the anode off gas. Next, it is checked whether or not the anode inlet pressure P2 has reached the pressure value Pk3 or less (step S36). When the pressure P2 has reached the pressure value Pk3 or less (step S36; YES), the rotational speed of the air compressor 52 is normally set. The rotational speed is restored (step S37).

  Although the battery operation is performed as described above, when the power load is small, the fuel cell 20 can be driven by power supply without operating the fuel cell 20, so the operation of the fuel cell 20 is temporarily stopped and intermittent. It is preferable to operate. Therefore, it is checked whether or not the intermittent operation start condition is satisfied (step S38). If the intermittent operation start condition is not satisfied (step S38; NO), the process jumps to step S11. When the intermittent operation start condition is satisfied (step S38; YES), all the shutoff valves A1 to A5 are closed in preparation for the battery operation suspension (step S39), and hydrogen leakage determination is performed (step S40). This hydrogen leakage determination may be performed again by performing the same processing as in steps S2 to S9 described above. In this way, if the mode is shifted to the intermittent operation mode, it is checked whether or not the intermittent operation cancellation condition is satisfied (step S41). If the intermittent operation cancellation condition is not satisfied (step S41; NO), the process jumps to step S38.

  On the other hand, when the intermittent operation cancellation condition is satisfied (step S41; YES), all the shutoff valves A1 to A4 are opened in preparation for resuming the battery operation (step S42), and the high pressure regulator A6 is operated to supply high pressure fuel gas to the fuel. The battery 20 is supplied. Further, the rotation speed of the hydrogen circulation pump 55 is increased, and the fuel gas is further pressurized (step S43). When the intermittent operation is released, the fuel gas pressure is reduced due to cross leaks, etc., so that high-pressure fuel gas is supplied to the fuel cell 20 to relatively reduce the partial pressure of nitrogen or the like and perform stable power generation. Can do. When the gas pressures P2 to P4 of each part of the fuel gas supply system become equal to or higher than the pressure value Pk4 (step S44; YES), the gas pressure of the fuel gas supply system has been increased to a necessary and sufficient gas pressure. The valve is closed (step S45), and the low pressure regulator A7 is operated.

  Finally, it is checked whether or not there is a system stop request (step S46). If there is no system stop request (step S46; NO), the process jumps to step S11. When there is a system stop request (step S46; YES), the shutoff valves A1 and A2 are closed (step S47), and the fuel gas supply is stopped. Further, low-current power generation is performed to consume residual fuel gas (step S48). When the anode inlet gas pressure P2 becomes equal to or lower than the pressure value Pk5 (step S49; YES), the hydrogen circulation pump 55 is stopped (step S50), and the power generation is further stopped (step S51). Subsequently, by opening the shutoff valve A5 (step S52), residual hydrogen in the hydrogen circulation system is exhausted. When the anode inlet gas pressure P2 becomes equal to or lower than the pressure value Pk6 (step S53; YES), the shutoff valves A3 to A5 are closed (step S54). After a predetermined time t2 has elapsed from the closing time of the shutoff valves A3 to A5 (step S55; YES), the air compressor 52 is stopped (step S56), and the process jumps to step S1.

  According to the present embodiment, since the switching control between the high pressure regulator A6 and the low pressure regulator A7 can be performed by opening / closing the shutoff valve A2 installed upstream of the high pressure regulator A6, the fuel gas supplied to the fuel cell The pressure can be adjusted to different pressure values with a simple system configuration. Further, by installing the shutoff valve A2 upstream of the high pressure regulator A6, the shutoff valve A2 can be designed to have a low flow rate, and the shutoff valve A2 can be reduced in size and pressure loss can be reduced.

Embodiment 2 of the Invention
FIG. 8 shows the configuration of the pressure adjusting unit 71 of the fuel cell system according to the second embodiment of the present invention. The present embodiment includes a configuration in which the pressure adjusting unit 70 is replaced with a pressure adjusting unit 71 in the configuration of the first embodiment. In order to regulate the pressure of the fuel gas supplied to the fuel cell 20, the pressure regulation unit 71 includes a plurality of regulators A6 to A8 that are set to high pressure, intermediate pressure, and low pressure regulation pressure, and regulators A6 to A8 in parallel. The reaction gas supply path 31 including a plurality of branch / combining flow paths 31a to 31c connected to the A, and the shutoff valves A9 and A2 disposed in series with respect to each of the intermediate pressure regulator A8 and the high pressure regulator A6. ing. By using a plurality of regulators A6 to A8 having different set pressures, the fuel gas pressure can be regulated over a wide range from high pressure to low pressure according to the power load of the fuel cell 20 even if the dynamic range per regulator is narrow. . In addition, there is an advantage that the larger the number of regulators, the easier it is to make a pressure adjustment range.

  The controller 60 can switch the operation of the regulators A6 to A8 by controlling the shutoff valves A2 and A9 to open and close. For example, when all the shutoff valves A2 and A9 are closed, only the low pressure regulator A7 operates. When the shutoff valve A9 is opened and the shutoff valve A2 is closed, only the intermediate pressure regulator A8 operates, and the low pressure regulator A7 shuts off the passage of fuel gas by the self-sealing function. When the shutoff valve A9 is closed and the shutoff valve A2 is opened, only the high pressure regulator A6 operates, and the low pressure regulator A7 shuts off the passage of fuel gas by the self-sealing function. The installation positions of the shutoff valves A2 and A9 are particularly limited as long as they are in the downstream side of the branch point B1 of the branch / joint flow paths 31a to 31c and in the upstream side of the join point B2. Although not intended, positions upstream of the intermediate pressure regulator A8 and the high pressure regulator A6 are desirable. By installing the shut-off valves A2 and A9 upstream of the regulator, a low flow rate design can be achieved and downsizing can be realized.

  When N regulators are connected in parallel (N is an integer of 3 or more), a cutoff valve is connected in series to each of the (N-1) regulators excluding the regulator set to the lowest pressure ( By installing (N-1) pieces and controlling the opening and closing of these (N-1) shut-off valves, the N regulators can be switched and controlled. (N-1) To perform open / close control of the number of regulators, it is only necessary that the shutoff valve corresponding to the regulator with the set pressure higher than the target pressure is closed, and the regulator with the set pressure lower than the target pressure is supported. The shut-off valve to be operated may be either opened or closed.

Embodiment 3 of the Invention
FIG. 9 shows the configuration of the pressure adjusting unit 72 of the fuel cell system according to the third embodiment of the present invention. The present embodiment has a configuration in which the pressure adjusting unit 70 is replaced with a pressure adjusting unit 72 in the configuration of the first embodiment. The pressure adjusting unit 72 is pressure-set to supply high-pressure fuel gas in a high-load to medium-load range and to supply low-pressure fuel gas in a medium-load to low-load range. The low-pressure regulator A11 and the reaction gas supply path 31 including a plurality of branching / combining flow paths 31a and 31b that connect the regulators A10 and A11 in parallel, respectively. The high pressure regulator A10 is configured, for example, as a pneumatic proportional pressure control valve, and inputs the air pressure supplied from the signal pressure supply means 80 as a signal pressure and controls the pressure reduction so that the fuel gas pressure falls within a predetermined pressure range. . As the signal pressure supply means 80, an air compressor capable of supplying a signal pressure to the high pressure regulator A10 via a working medium such as air is suitable. The controller 60 controls the signal pressure supplied to the high pressure regulator A10 according to the power load. Specifically, high-pressure air is supplied to the high-pressure regulator A10 so that only the low-pressure regulator A11 operates in the range of low load to medium load. The signal pressure is adjusted so that the high pressure regulator A10 operates in the middle load to high load range. In a state where the high-pressure regulator A10 is operating, the low-pressure regulator A11 blocks the passage of fuel gas by a self-sealing function. According to this configuration, since a shut-off valve for switching and controlling the regulator is not necessary, the system configuration can be simplified.

  When N regulators are connected in parallel (N is an integer of 3 or more), (N-1) regulators excluding the regulator set to the lowest pressure can be replaced with, for example, the pneumatic proportional pressure described above. It may be configured as a control valve so that only one of the regulators is operated by controlling the opening and closing of the proportional pressure control valve.

1 is a configuration diagram of a fuel cell system according to a first embodiment. 6 is a flowchart describing a fuel cell operation control routine. 6 is a flowchart describing a fuel cell operation control routine. 6 is a flowchart describing a fuel cell operation control routine. 6 is a flowchart describing a fuel cell operation control routine. 6 is a flowchart describing a fuel cell operation control routine. 6 is a flowchart describing a fuel cell operation control routine. It is a block diagram of the pressure regulation part in connection with 2nd Embodiment. It is a block diagram of the pressure regulation part in connection with 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 20 ... Fuel cell 31 ... Fuel gas supply path 31a, 31b ... Branching / joining flow path 60 ... Control part 70 ... Pressure regulation part A2 ... Shut-off valve A6 ... High pressure regulator A7 ... Low pressure regulator

Claims (3)

A plurality of regulators each set to a different adjustment pressure to regulate the pressure of the reaction gas supplied to the fuel cell;
A reaction gas supply path including a plurality of branching / combining flow paths each connecting the plurality of regulators in parallel;
For each of a single regulator or a plurality of regulators excluding the regulator set with the lowest adjustment pressure among the plurality of regulators, the branching / merging channel is downstream of the branching point where the branching / merging channel branches. A single or a plurality of shut-off valves connected in series on the upstream side of the junction where the paths meet;
A controller that regulates the supply pressure of the reaction gas supplied to the fuel cell by controlling the opening or closing of the single or multiple shutoff valves;
A fuel cell system comprising: The fuel cell system according to claim 1,
The fuel cell system, wherein the shut-off valve is disposed upstream of the regulator. A plurality of regulators for regulating the pressure of the reaction gas supplied to the fuel cell according to the signal pressure;
A reaction gas supply path including a plurality of branching / combining flow paths each connecting the plurality of regulators in parallel;
By supplying a signal pressure to each of a single regulator or a plurality of regulators excluding a regulator set with the lowest adjustment pressure among the plurality of regulators, any one of the regulators is operated. Signal pressure supply means for adjusting the supply pressure of the reaction gas supplied to the fuel cell;
A fuel cell system comprising:

Images