JP2005235546A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system restraining power voltage at start of fuel-gas supply, correctly judging that the gas at a fuel electrode is replaced by fuel-gas. <P>SOLUTION: When starting the fuel cell system, a controller 2 controls a compressor 21 in a state of not supplying oxidant gas to an air electrode 1b, controls the opening level of a hydrogen pressure control valve 12 for supplying hydrogen gas to a hydrogen electrode 1b, and makes the fuel cell consume the power voltage at a preparatory load 4 so as to make the power voltage of the fuel cell 1 detected by a voltage sensor 3 get to a prescribed voltage or lower, until it is judged that the gas at the hydrogen electrode 1a is replaced by hydrogen gas. Further, the controller takes the amount of hydrogen consumed by the electrochemical reaction at the fuel cell 1 into consideration when it is judged that the gas at the hydrogen electrode 1a is replaced by hydrogen gas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system that supplies an oxidant gas to an oxidant electrode of a fuel cell stack and generates power by supplying the fuel gas to a fuel electrode.

  2. Description of the Related Art Conventionally, a fuel cell system that supplies hydrogen gas to a fuel electrode and supplies air to an oxidant electrode to generate power when generating power from the fuel cell stack is known.

  In such a fuel cell system, as described in Patent Document 1 below, the entire fuel electrode is sufficiently replaced with the fuel gas by supplying only the fuel gas to the fuel electrode at the time of starting the system. Thereafter, the fuel cell stack is connected to an external load substantially simultaneously with the start of supply of the oxidant gas to the oxidant electrode. Thus, conventionally, the fuel cell stack is prevented from becoming a high voltage state in a no-load state, the deterioration due to the corrosion of the catalyst layer of the oxidizer electrode is suppressed, and the fuel due to the shortage of fuel gas in the fuel electrode Degradation due to corrosion of the electrode catalyst layer is suppressed.

  In addition, the conventional fuel cell system has a long elapsed time after the previous system shutdown, and when the oxygen is sufficiently present in the oxidizer electrode due to diffusion or the like, the fuel gas is sufficiently supplied at the start of fuel gas supply. A portion that is supplied and a portion that is not supplied are generated, and a high voltage state is generated in a portion where the fuel gas is sufficiently supplied, which may cause catalyst corrosion. On the other hand, in the following Patent Document 2, in order to avoid a high voltage state in an unloaded state, after supplying fuel gas, a preliminary load provided separately from the drive motor or the like is applied to the fuel cell stack. The power generation voltage is connected and consumed so as to be a predetermined value or less, and deterioration due to corrosion of the catalyst layer is suppressed.

Further, in Patent Document 3 below, when a non-fuel gas component in a fuel gas piping path connected to a fuel electrode is replaced with a fuel gas, a fuel gas supply is caused by a difference in molecular weight between the non-fuel gas and the fuel gas. The fuel gas pressure value with respect to the fuel gas amount or the fuel gas supply amount with respect to the fuel gas pressure is determined, it is determined whether the fuel electrode is replaced with the fuel gas by the supplied fuel gas, and the catalyst layer on the fuel electrode side due to the fuel gas shortage is determined. It suppresses corrosion and deterioration, and the emission of fuel gas more than necessary.
JP-A-9-120830 Japanese Patent Publication No. 7-63020 JP 2002-313390 A

  However, in the above-described conventional fuel cell system described in Patent Document 2, after starting the supply of the fuel gas, the fuel cell stack is controlled to a predetermined value or less at which the generated voltage of the fuel cell stack does not cause corrosion of the catalyst layer. In the technology that waits until the electrode is replaced with the fuel gas, the fuel cell stack is considered to suppress the generated voltage when the supply of the fuel gas is started, and the fuel electrode is filled with the non-fuel gas. It is necessary to replace with a high gas concentration in a short time.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and suppresses the power generation voltage at the start of fuel gas supply and can accurately determine that the fuel electrode has been replaced with fuel gas. An object is to provide a battery system.

  According to the present invention, a fuel gas is supplied to a fuel electrode, an oxidant gas is supplied to an oxidant electrode, and power is generated. A fuel gas supply channel connected to a fuel gas inlet of the fuel cell is provided. A fuel gas supply means for supplying a fuel gas to the fuel electrode of the fuel cell and discharging the fuel gas discharged from the fuel cell through a fuel gas discharge channel connected to the fuel gas outlet of the fuel cell; The oxidant gas is supplied to the oxidant gas electrode of the fuel cell via the oxidant gas supply channel connected to the oxidant gas inlet, and the oxidant gas discharge channel connected to the oxidant gas outlet of the fuel cell is provided. An oxidant gas supply means for discharging the oxidant gas discharged from the fuel cell, a power consumption means for consuming the power generated by the fuel cell and adjusting the power generation voltage of the fuel cell, and a power generation voltage of the fuel cell. Equipped with power generation voltage detection means to detect In the fuel cell system, at the time of system start-up, the start-up control means controls the fuel gas supply means so as to supply the fuel gas to the fuel electrode without supplying the oxidant gas to the oxidant electrode. The power consumption means consumes the power generation voltage so that the power generation voltage of the fuel cell detected by the power generation voltage detection means is equal to or lower than a predetermined value until it is determined that the fuel gas is replaced by the fuel gas. To do.

  According to the fuel cell system of the present invention, power generation of the fuel cell is performed until it is determined that the fuel electrode is replaced with the fuel gas without supplying the oxidant gas to the oxidant electrode and supplying the fuel gas to the fuel electrode. Since the generated voltage is consumed by the power consuming means so that the voltage becomes a predetermined value or less, it is possible to suppress the energy that causes the corrosion of the electrode catalyst, and it is determined that the fuel electrode is surely replaced with the fuel gas. Therefore, it is possible to avoid a situation in which the fuel gas in the fuel electrode becomes insufficient after shifting to normal power generation.

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

[First Embodiment]
The present invention is applied to the fuel cell system according to the first embodiment configured as shown in FIG. 1, for example. This fuel cell system is mounted on a vehicle, for example, and supplies power to a load such as a drive motor that generates a running torque of the vehicle and charges the storage battery with power.

[Configuration of fuel cell system]
As shown in FIG. 1, the fuel cell system includes a fuel cell stack 1 that generates electric power when supplied with a fuel gas and an oxidant gas. The fuel cell stack 1 is configured, for example, by laminating a plurality of fuel cell structures each having a hydrogen electrode 1a and an air electrode 1b facing each other with a solid polymer electrolyte interposed therebetween. In this example, the fuel cell stack 1 supplies hydrogen gas as a fuel gas for generating an electrochemical reaction to the hydrogen electrode 1a, and supplies air containing oxygen as an oxidant gas to the air electrode 1b. Will be described.

  The fuel cell system includes an air system for supplying and discharging air to the fuel cell stack 1 and a hydrogen gas system for supplying hydrogen gas to the fuel cell stack 1. In this example, the illustration of a humidifying pure water system for circulating humidifying pure water for humidifying the fuel cell stack 1 and a cooling water system for circulating cooling water for adjusting the temperature of the fuel cell stack 1 are omitted. In this fuel cell system, when the power generation of the fuel cell stack 1 is controlled, each part of the hydrogen gas system and the air system is controlled by the controller 2.

  The hydrogen gas system is provided with a hydrogen cylinder 11, a hydrogen pressure regulating valve 12, and an actuator 13 in a hydrogen supply channel L 1 connected to the hydrogen gas inlet of the fuel cell stack 1, and is connected to the hydrogen gas outlet of the fuel cell stack 1. The purge valve 14 and the actuator 15 are provided in the hydrogen discharge flow path L2 thus configured.

  This hydrogen gas system guides high-pressure hydrogen stored in the hydrogen cylinder 11 to the hydrogen electrode 1a as hydrogen gas during normal operation of the fuel cell system. At this time, in the hydrogen gas system, the actuator 13 is driven by the controller 2 and the opening degree of the hydrogen pressure regulating valve 12 is adjusted. As a result, the hydrogen gas is regulated to an appropriate pressure by the hydrogen pressure regulating valve 12 and introduced into the hydrogen electrode 1a. The controller 2 adjusts the opening of the hydrogen pressure regulating valve 12 so as to obtain a desired pressure with reference to a detected value of an anode electrode pressure sensor (not shown) that detects a gas pressure in the hydrogen electrode 1a. I do.

  Further, this hydrogen gas system releases impurities together with hydrogen gas to the outside air by driving the actuator 15 so that the purge valve 14 is opened when impurities other than hydrogen gas accumulate in the hydrogen electrode 1a. To do.

  In such a hydrogen gas system, in order to replace the gas in the hydrogen supply flow path L1 and the hydrogen electrode 1a with hydrogen when the fuel cell system is started up, air is not supplied to the air electrode 1b by the air system described later, Control is performed so that only hydrogen gas is supplied to the hydrogen electrode 1a.

  In the air system, a compressor 21 is provided in an air supply passage L3 connected to the air inlet of the air electrode 1b, and an air pressure regulating valve 22 and an actuator 23 are provided in an air discharge passage L4 connected to the air outlet of the air electrode 1b. It is provided and configured.

  In the air system, during the normal operation of the fuel cell system, the rotation speed of the compressor motor (not shown) of the compressor 21 is controlled by the controller 2, and outside air is taken in and introduced into the air inlet of the air electrode 1b as compressed air. . At this time, the controller 2 refers to the detected value of the air pressure sensor (not shown), drives the actuator 23 so that the air pressure in the air electrode 1b becomes a desired pressure value, and opens the opening of the air pressure regulating valve 22. Make adjustments. The air discharged from the air outlet of the fuel cell stack 1 passes through the air discharge flow path L4 and the air pressure regulating valve 22, and is discharged to the outside air.

  Such an air system is in a state in which air is not supplied to the air electrode 1b so that hydrogen gas constantly flows through the hydrogen supply channel L1 and the hydrogen electrode 1a when the fuel cell system is started.

  Further, the fuel cell system includes a voltage sensor 3 that detects a power generation voltage of the fuel cell stack 1 and a preliminary load 4 that is provided separately from a load such as the drive motor described above.

  The voltage sensor 3 detects the power generation voltage of the fuel cell stack 1, and the power generation voltage is read into the controller 2 as a sensor signal. This sensor signal is used when the controller 2 controls the power generation amount of the fuel cell stack 1 or for monitoring the state of the fuel cell stack 1.

  The preliminary load 4 is provided for consuming generated power generated at the time of starting the fuel cell system and starting the supply of hydrogen gas. The preliminary load 4 includes, for example, a dummy resistor and a switch. When the controller 2 is opened (opened) by the controller 2, the generated power is not consumed by the dummy resistor, and the switch 2 is switched by the controller 2. When is closed (conductive state), the generated power is consumed by the dummy resistor. The preliminary load 4 is applied with a high voltage that causes the switch to be closed by the controller 2 at the start of the fuel cell system and suppresses the deterioration of the cathode catalyst corrosion of the fuel cell stack 1. The preliminary load 4 may have a fixed resistance value or a variable resistance value. In short, the power generation voltage of the fuel cell stack 1 is set to a predetermined value or less which does not cause corrosion of the cathode electrode catalyst. I just need it.

  The controller 2 includes a CPU (Central Processing Unit) that executes a procedure for performing a startup process of a fuel cell system, which will be described later, and an interface circuit with each of the above-described units. This controller 2 controls each part mentioned above, for example according to the starting command of the fuel cell system from the outside, and also the drive torque requested | required of the vehicle drive motor.

[Startup process of fuel cell system]
Next, the startup process of the fuel cell system configured as described above will be described with reference to the flowchart of FIG. 2 and the timing chart of FIG.

  In this activation process, for example, when the driver turns on the IGN switch of the vehicle, a process for starting the fuel cell system is input to the controller 2, and the processes after step S1 are started.

  First, in step S1, the controller 2 maintains the compressor 21 in a stopped state so that the hydrogen supply amount to the hydrogen electrode 1a is constant while the air supply to the air electrode 1b is shut off. The opening degree of the pressure regulating valve 12 is adjusted. At this time, the controller 2 controls the actuator 15 so that the purge valve 14 is opened at a predetermined opening. In contrast, in the fuel cell system, supply of hydrogen gas to the hydrogen electrode 1a is started at time t1, and the hydrogen gas flow rate rises to a predetermined flow rate at time t12 (FIG. 3B).

  Thereby, hydrogen gas is introduced into the hydrogen electrode 1a from the hydrogen cylinder 11 via the hydrogen pressure regulating valve 12, and residual gas existing in the hydrogen supply flow path L1 and the hydrogen electrode 1a is started to be discharged to the outside.

  In step S1, air is not supplied to the air electrode 1b because the compressor 21 is stopped (FIG. 3A), but oxygen remains in the air electrode 1b during the stop period of the fuel cell system. As a result, the electrochemical reaction using the hydrogen gas started to be supplied from time t1 and the remaining oxygen is started, and the generated voltage (FIG. 3C) rises from time t1. The rise of the generated voltage is detected by the voltage sensor 3 and recognized by the controller 2.

  When supply of hydrogen gas is started in this way, the molecular weight (gas density) of the residual gas (air) of the hydrogen electrode 1a is higher than the molecular weight of the hydrogen gas (for example, about 14 times). It is difficult to be discharged. Accordingly, the discharge flow rate of the residual gas is small with respect to the hydrogen gas supply flow rate to the hydrogen electrode 1a, the pressure in the hydrogen electrode 1a becomes high (FIG. 3 (e)), and the residual from the purge valve 14 is first more than hydrogen. The gas is discharged first, and gradually the mixed gas of hydrogen gas and residual gas begins to be discharged.

  Next, the controller 2 performs the operation | movement which suppresses the electric power generation voltage which rose in step S1 in step S2. At this time, the controller 2 electrically connects the electrodes of the hydrogen electrode 1a and the air electrode 1b to the preliminary load 4 and applies the generated voltage of the fuel cell stack 1 to the preliminary load 4, thereby supplying current to the preliminary load 4. . Further, the controller 2 conducts the fuel cell stack 1 and the preload 4 when the current power generation voltage detected by the voltage sensor 3 exceeds a predetermined value that causes corrosion of the cathode electrode catalyst. You may let them.

  As a result, the generated current starts to flow to the reserve load 4 from time t2 slightly delayed from time t1, and when the generated current increases to the peak value (FIG. 3D), the generated voltage starts to decrease (FIG. 3C). )). When the power generation voltage decreases in this way, the energy for the progress of corrosion of the cathode electrode catalyst is suppressed.

  As described above, after the processing of Step S1 and Step S2, the residual gas is discharged, and the gas discharged from the purge valve 14 becomes richer in hydrogen, that is, the higher the hydrogen concentration in the hydrogen electrode 1a, As shown after time t3, the gas pressure in the hydrogen electrode 1a decreases.

  Next, in step S3, the controller 2 detects the gas pressure in the hydrogen electrode 1a, and the gas in the hydrogen electrode 1a obtained by adding the correction by the electrochemical reaction of the fuel cell stack 1 to the current gas pressure in the hydrogen electrode 1a. It is determined whether the pressure is equal to or less than a predetermined value P2. The gas pressure correction process will be described later.

  When the controller 2 determines that the corrected gas pressure in the hydrogen electrode 1a is not lower than the predetermined value P2, the controller 2 repeats this determination, and determines that the corrected pressure is lower than the predetermined value P2. In step S4, the process proceeds.

  Then, the controller 2 determines at time t5 that the operation of replacing the residual gas in the hydrogen electrode 1a with hydrogen gas has been completed in step S4, and at time t5, the compressor 2 is driven and the air pressure regulating valve in step S5. The actuator 23 is controlled so as to open 22 and supply of air to the air electrode 1b is started, and, for example, a transition is made to normal power generation that supplies hydrogen and air in accordance with the required torque of the drive motor ( FIG. 3 (a), (b)).

"Gas pressure correction process"
The correction process performed in step S3 is for determining whether or not the replacement with the hydrogen gas in the hydrogen electrode 1a is completed in consideration of the amount of hydrogen gas consumed by the electrochemical reaction in the hydrogen electrode 1a. The gas pressure in the hydrogen electrode 1a is corrected.

  If hydrogen is not consumed by an electrochemical reaction after the supply of hydrogen gas after step S1 is started, it is necessary to discharge from the purge valve 14 the same amount of gas supplied from the hydrogen cylinder 11 to the hydrogen electrode 1a. . For this reason, the pressure in the hydrogen electrode 1a changes with time as shown in the characteristic B of FIG. 3E, and the pressure of the hydrogen electrode 1a when the replacement of the hydrogen electrode 1a with hydrogen gas is completed becomes P2. .

  On the other hand, when the supply of hydrogen gas to the hydrogen electrode 1a is started in a state where oxygen is present in the air electrode 1b, the hydrogen gas supplied by the electrochemical reaction is consumed and discharged from the purge valve 14. The amount of gas that should be reduced. For this reason, as shown in the characteristic A of FIG. 3E, the pressure in the hydrogen electrode 1a changes with time in a state lower than the characteristic B, and when the replacement of the hydrogen electrode 1a with hydrogen gas is completed. The pressure of the hydrogen electrode 1a is P1 lower than P2.

  Therefore, when the predetermined value in step S3 is set to P2 without considering the amount of hydrogen consumed by the electrochemical reaction, the actual hydrogen gas pressure becomes as shown in the characteristic A. In this example, the hydrogen gas is changed to hydrogen gas. The time t4 is earlier than the time t5 at which it is determined that the replacement has been completed.

  Therefore, the controller 2 of the fuel cell system according to the first embodiment monitors, for example, a power generation current flowing through the preliminary load 4 by a current sensor (not shown), and does not contribute to the replacement of the generated current value with hydrogen gas. Estimate the amount of hydrogen consumed by the reaction. Next, the controller 2 estimates the pressure in the hydrogen electrode 1 a necessary for discharging from the purge valve 14 a hydrogen amount obtained by adding the estimated consumed hydrogen amount and the hydrogen amount currently discharged from the purge valve 14. The estimated pressure in the hydrogen electrode 1a is set to a predetermined value P2. At this time, for example, the controller 2 reads a sensor signal of a flow rate sensor (not shown) that detects the amount of hydrogen passing through the purge valve 14 and obtains the amount of hydrogen actually discharged from the purge valve 14.

Specifically, the controller 2 uses an arithmetic expression as shown in the following Expression 1 for obtaining the volume flow rate passing through the purge valve 14.

Here, in Equation 1, Q is the volume flow rate, A is the opening area of the purge valve 14, ρ0 is the gas density, κ is the specific heat ratio, p0 is the upstream pressure of the purge valve 14, and pe is the downstream pressure of the purge valve 14. . In Equation 1, κ, pe, ρ0 can be assumed to be constant, and the volume flow rate Q is obtained by adding the amount of hydrogen consumed based on the generated current and the amount of hydrogen discharged from the purge valve 14 to Then, the upstream pressure of the purge valve 14 (gas pressure of the hydrogen electrode 1a) p0 can be obtained as the corrected gas pressure of the hydrogen electrode 1a. Then, the controller 2 compares the corrected gas pressure of the hydrogen electrode 1a obtained by Equation 1 with the predetermined value P2.

[Effect of the first embodiment]
As described above in detail, according to the fuel cell system according to the first embodiment to which the present invention is applied, hydrogen gas is supplied to the hydrogen electrode 1a without supplying oxygen to the air electrode 1b, and the hydrogen electrode 1a. Until it is determined that the replacement with hydrogen gas is completed, the preload 4 is connected to the fuel cell stack 1 so that the power generation voltage generated by the residual oxygen in the air electrode 1b is below a predetermined value. The energy for advancing corrosion can be suppressed, and it can be determined that the hydrogen electrode 1a has been reliably replaced with hydrogen gas, so that the hydrogen gas in the hydrogen electrode 1a runs short after shifting to normal power generation. Can be avoided.

  Further, according to this fuel cell system, when the hydrogen gas flow rate is constant at the time of starting the system, the gas pressure in the fuel cell stack 1 that becomes lower as the residual gas in the hydrogen electrode 1a is replaced with hydrogen gas. When the amount of hydrogen consumed by the electrochemical reaction is corrected as not contributing to the replacement, and the replacement with hydrogen gas is completed assuming that the corrected gas pressure and consumption by the electrochemical reaction do not occur Is compared with the gas pressure P2 in the hydrogen electrode 1a to determine whether or not the replacement of the hydrogen electrode 1a with the hydrogen gas is completed, so that the replacement with the hydrogen gas in the hydrogen electrode 1a is more accurately determined. can do.

  Further, according to this fuel cell system, since the amount of hydrogen consumed by the electrochemical reaction is estimated from the actual current value, the amount of residual oxygen in the air electrode 1b changes every time the system is started. Even when the rising of the amount of power generation at the start of supply changes, it can be accurately determined that the hydrogen electrode 1a has been replaced with hydrogen gas.

  Further, according to this fuel cell system, the amount of hydrogen required for replacement with hydrogen gas in the hydrogen electrode 1a can be adjusted depending on whether the elapsed time from the previous stop time is long or short, for example, When there is little residual oxygen to the air electrode 1b, it is not necessary to supply extra hydrogen gas, and it can suppress that hydrogen gas is wasted.

[Second Embodiment]
Next, a fuel cell system according to a second embodiment will be described. In addition, about the part similar to the above-mentioned 1st Embodiment, the detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  The fuel cell system according to the second embodiment adjusts the opening of the hydrogen pressure regulating valve 12 so as to supply hydrogen gas with a constant gas pressure in the hydrogen electrode 1a at the time of system startup, and by electrochemical reaction. It differs from the first embodiment in that the opening of the hydrogen pressure regulating valve 12 is corrected according to the amount of hydrogen consumed to determine whether the replacement of the hydrogen electrode 1a with hydrogen gas has been completed.

  As shown in FIG. 4 for the starting process in the second embodiment, the controller 2 first opens the purge valve 14 in step S11 and does not supply air to the air electrode 1b (FIG. 5A). Then, supply of hydrogen gas to the hydrogen electrode 1a is started by adjusting the opening of the hydrogen pressure regulating valve 12 so that the gas pressure in the hydrogen electrode 1a is constant. Thereby, supply of hydrogen gas to the hydrogen electrode 1a is started at time t11, the hydrogen gas flow rate rises to a predetermined flow rate at time t12 (FIG. 5B), and the hydrogen supply flow path L1 and the hydrogen electrode 1a are supplied. The existing gas starts to be discharged to the outside.

  Then, an electrochemical reaction occurs using the residual oxygen in the air electrode 1b and the hydrogen gas that has started to be supplied, and the generated voltage (FIG. 5 (c)) rises from time t11. By making the load 4 conductive, the generated current (FIG. 5D) rises from time t12. At this time, since much hydrogen gas in the hydrogen electrode 1a is consumed, the opening degree of the hydrogen pressure regulating valve 12 is increased.

  Thereafter, when the opening degree of the purge valve 14 is constant, the molecular weight of the residual gas (air) of the hydrogen electrode 1a is higher than the molecular weight of the hydrogen gas. Therefore, in order to keep the gas pressure in the hydrogen electrode 1a constant, it is necessary to gradually reduce the opening of the hydrogen pressure regulating valve 12. When the residual gas in the hydrogen electrode 1a gradually decreases and the amount of hydrogen gas increases, the amount of gas exhausted from the purge valve 14 increases, and the opening of the hydrogen pressure adjustment valve 12 gradually increases after time t13. Increase the size (FIG. 5E).

  Next, in step S12, the controller 2 determines that the opening degree of the hydrogen pressure adjusting valve 12 obtained by adding the correction by the electrochemical reaction of the fuel cell stack 1 to the opening degree of the hydrogen pressure adjusting valve 12 that is currently controlled. It is determined whether or not the value is equal to or greater than a predetermined value a2. The correction process of the opening degree of the hydrogen pressure regulating valve 12 will be described later.

  When the controller 2 determines that the corrected opening of the hydrogen pressure adjusting valve 12 is not equal to or greater than the predetermined value a2, the controller 2 repeats this determination, and the corrected opening of the hydrogen pressure adjusting valve 12 is the predetermined value. If it is determined that the value is greater than or equal to a2, the process proceeds to step S4.

  Then, the controller 2 determines at time t15 that the operation of replacing the residual gas in the hydrogen electrode 1a with hydrogen gas has been completed in step S4, and starts supplying air to the air electrode 1b in step S5. Then, for example, the system shifts to normal power generation that supplies the amount of hydrogen and the amount of air corresponding to the required torque of the drive motor (FIGS. 5A and 5B).

“Adjustment of the opening of the hydrogen pressure regulating valve 12”
The correction process performed in step S12 is hydrogen for determining whether or not the replacement with the hydrogen gas in the hydrogen electrode 1a is completed in consideration of the amount of hydrogen gas consumed by the electrochemical reaction in the hydrogen electrode 1a. The opening degree of the pressure regulating valve 12 is corrected.

  If the hydrogen gas pressure after step S11 is kept constant, if the hydrogen is not consumed by the electrochemical reaction, the molecular weight of the residual gas in the hydrogen electrode 1a is higher than the molecular weight of the hydrogen gas, so it must be supplied. There is less hydrogen supply. At this time, since the hydrogen electrode pressure is constant, when discharging heavy gas, it is necessary to reduce the amount of supplied hydrogen, and the opening degree of the hydrogen pressure regulating valve 12 is as shown by the characteristic D in FIG. When the hydrogen electrode 1a is completely replaced with hydrogen gas, the opening degree of the hydrogen pressure regulating valve 12 becomes a2.

  On the other hand, when the hydrogen gas supplied by the electrochemical reaction is consumed, it is necessary to increase the amount of hydrogen gas supplied to the hydrogen electrode 1a in order to make the gas pressure in the hydrogen electrode 1a constant. As shown in characteristic C of FIG. 5 (e), the opening of the hydrogen pressure regulating valve 12 needs to be increased when an electrochemical reaction occurs, and therefore becomes larger than characteristic D, and the hydrogen electrode 1a When the replacement with hydrogen gas is completed, the opening degree of the hydrogen pressure regulating valve 12 is a1 which is larger than a2.

  Therefore, when the predetermined value in step S12 is set to a2 without considering the amount of hydrogen consumed by the electrochemical reaction, the actual opening degree of the hydrogen pressure regulating valve 12 becomes as shown in the characteristic C. In the example, the time t14 is earlier than the time t15 when it is determined that the replacement with hydrogen gas is completed.

  Therefore, the controller 2 of the fuel cell system according to the second embodiment estimates the hydrogen supply amount from the actual opening of the hydrogen pressure regulating valve 12 and generates the amount of hydrogen consumed by the electrochemical reaction that does not contribute to the substitution. Estimated from current. Then, the controller 2 estimates the opening a2 of the hydrogen pressure regulating valve 12 necessary for supplying the hydrogen amount obtained by subtracting the estimated consumed hydrogen amount from the estimated hydrogen supply amount to the hydrogen electrode 1a.

  Specifically, the controller 2 uses an arithmetic expression as shown in the above equation 1 for obtaining the volume flow rate passing through the hydrogen pressure regulating valve 12. Here, A in Equation 1 is the opening area of the hydrogen pressure regulating valve 12, p0 is the upstream pressure of the hydrogen pressure regulating valve 12, pe is the downstream pressure of the hydrogen pressure regulating valve 12 (a constant gas pressure in the hydrogen electrode 1a). ). In Equation 1, κ, pe, and ρ0 can be assumed to be constant, and the volume flow rate Q is estimated from the estimated hydrogen supply amount using p0 that is known in advance according to the specifications of the hydrogen cylinder 11 or the like. Assuming that the amount of hydrogen is the amount obtained by subtracting the amount of hydrogen, A can be obtained as a change like the characteristic D. Then, the controller 2 compares the corrected opening degree of the hydrogen pressure regulating valve 12 obtained by Equation 1 with the predetermined value a2.

[Effects of Second Embodiment]
As described above in detail, according to the fuel cell system according to the second embodiment to which the present invention is applied, when the gas pressure in the hydrogen electrode 1a is kept constant at the time of system startup, the residual in the hydrogen electrode 1a. The opening degree of the hydrogen pressure regulating valve 12 that increases as the gas is replaced with hydrogen gas is corrected so that the amount of hydrogen consumed by the electrochemical reaction does not contribute to the replacement, and the corrected hydrogen pressure regulating valve 12 The opening degree is compared with the opening degree a2 of the hydrogen pressure regulating valve 12 when the replacement with hydrogen gas is completed when it is assumed that consumption due to an electrochemical reaction does not occur. Since it is determined whether or not the replacement is completed, it is possible to accurately determine the replacement with the hydrogen gas in the hydrogen electrode 1a.

  That is, according to this fuel cell system, it is possible to accurately determine that the interior of the hydrogen electrode 1a has been replaced with hydrogen gas, even when the rising of the amount of power generation when the supply of hydrogen gas is started changes. It is possible to avoid wasteful discharge of hydrogen gas, shortage of hydrogen gas when it is determined that the replacement is completed, and corrosion of the cathode electrode catalyst.

[Third Embodiment]
Next, a fuel cell system according to a third embodiment will be described. Note that parts similar to those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the fuel cell system according to the third embodiment branches from the hydrogen gas outlet of the fuel cell stack 1 and circulates hydrogen gas discharged from the hydrogen gas outlet to the hydrogen gas inlet. It differs from 1st Embodiment mentioned above by the point which provided the path L11 and provided the ejector pump 31 in the confluence | merging point of the said hydrogen circulation flow path L11 and the hydrogen supply flow path L1.

  Such a fuel cell system performs the process shown in FIG. 2 by the controller 2 in the same manner as in the first embodiment when the system is started, and performs the operation shown in FIG. Here, in step S1, the hydrogen gas flow rate obtained by adding the hydrogen gas flow rate that passes through the hydrogen pressure regulating valve 12 and the hydrogen gas flow rate that is introduced from the hydrogen circulation flow path L11 to the ejector pump 31 is constant. The opening degree of the pressure regulating valve 12 is adjusted. At this time, the controller 2 determines the flow rate of hydrogen that is taken into the ejector pump 31 from the hydrogen circulation passage L11 and introduced into the hydrogen electrode 1a according to the flow rate of the hydrogen gas that flows from the hydrogen cylinder 11 to the ejector pump 31. The opening of the hydrogen pressure regulating valve 12 is set so that the sum of the circulated hydrogen flow rate and the hydrogen flow rate directly introduced from the hydrogen cylinder 11 to the hydrogen electrode 1a is constant. adjust.

  According to such a fuel cell system according to the third embodiment, when hydrogen gas is circulated by the ejector pump 31 and supplied to the fuel cell stack 1 at the time of starting the system, the fuel cell system 1 is discharged from the fuel cell stack 1. In consideration of the amount of hydrogen gas circulated to the fuel cell stack 1 again, the hydrogen gas pressure for determining the replacement with the hydrogen gas in the hydrogen electrode 1a is corrected by the amount of hydrogen consumed in the hydrogen electrode 1a. Even if the generated voltage rises differently depending on the state, the hydrogen electrode 1a can be accurately replaced with hydrogen gas.

[Fourth Embodiment]
Next, a fuel cell system according to a fourth embodiment will be described. Note that parts similar to those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the fuel cell system according to the fourth embodiment branches from a hydrogen gas outlet of the fuel cell stack 1 and circulates hydrogen gas discharged from the hydrogen gas outlet to the hydrogen gas inlet. It differs from the second embodiment described above in that a path L11 is provided and an ejector pump 31 is provided at the junction of the hydrogen circulation flow path L11 and the hydrogen supply flow path L1.

  In such a fuel cell system, when the system is started, the controller 2 performs the process of FIG. 4 as in the first embodiment, and performs the operation shown in FIG. Here, in step S11, the opening degree of the hydrogen pressure regulating valve 12 is adjusted so that the gas pressure in the hydrogen electrode 1a is constant, and the fuel cell stack 1 and the preliminary load 4 are connected in step S2. In this state, whether the replacement of the hydrogen electrode 1a with the hydrogen gas is completed by the hydrogen gas introduced directly from the hydrogen cylinder 11 into the hydrogen electrode 1a in step S12 and the hydrogen gas circulated from the ejector pump 31 and introduced into the hydrogen electrode 1a. Determine whether or not.

  At this time, the controller 2 determines the flow rate of hydrogen that is taken into the ejector pump 31 from the hydrogen circulation passage L11 and introduced into the hydrogen electrode 1a according to the flow rate of the hydrogen gas that flows from the hydrogen cylinder 11 to the ejector pump 31. When the sum of the circulated hydrogen flow rate and the hydrogen flow rate directly introduced from the hydrogen cylinder 11 to the hydrogen electrode 1a is introduced into the hydrogen electrode 1a, the gas of the hydrogen electrode 1a is stored in advance. The opening degree of the hydrogen pressure regulating valve 12 is adjusted so that the pressure is constant.

  According to such a fuel cell system according to the fourth embodiment, when hydrogen gas is circulated by the ejector pump 31 and supplied to the fuel cell stack 1 at the time of starting the system, the fuel cell system 1 is discharged from the fuel cell stack 1. In consideration of the amount of hydrogen gas circulated to the fuel cell stack 1 again, the opening of the hydrogen pressure regulating valve 12 for determining replacement with the hydrogen gas in the hydrogen electrode 1a is corrected. Even in the case where the rising direction of is different, the hydrogen electrode 1a can be accurately replaced with hydrogen gas.

[Fifth Embodiment]
Next, a fuel cell system according to a fifth embodiment will be described. Note that parts similar to those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell system according to the fifth embodiment has the configuration shown in FIG. 6 and corrects the gas pressure between the hydrogen pressure regulating valve 12 and the ejector pump 31, and the corrected gas pressure is as described above. In this case, it is different from the above-described embodiment in that it is determined that the replacement of the hydrogen electrode 1a with the hydrogen gas is completed.

  As shown in FIG. 7 for the startup process in the fifth embodiment, the controller 2 first opens the purge valve 14 in step S11 and does not supply air to the air electrode 1b (FIG. 8A). The opening degree of the hydrogen pressure regulating valve 12 is adjusted so that the gas pressure in the hydrogen electrode 1a is constant. Thereby, supply of hydrogen gas to the hydrogen electrode 1a is started at time t21, the hydrogen gas flow rate rises to a predetermined flow rate at time t22 (FIG. 8B), and the hydrogen supply flow path L1 and the hydrogen electrode 1a are supplied. The existing gas starts to be discharged to the outside.

  Then, an electrochemical reaction occurs using the residual oxygen in the air electrode 1b and the hydrogen gas that has started to be supplied, and the generated voltage (FIG. 8 (c)) rises from time t21. By making the load 4 conductive, the generated current (FIG. 8D) rises from time t22.

  When the residual gas in the hydrogen electrode 1a gradually decreases and the amount of hydrogen gas increases, the amount of gas discharged from the purge valve 14 increases, and the opening of the hydrogen pressure adjustment valve 12 gradually increases after time t23. By increasing the pressure, the gas pressure downstream of the hydrogen pressure regulating valve 12 increases (FIG. 8 (e)).

  Next, in step S <b> 21, the controller 2 determines that the gas pressure downstream of the hydrogen pressure adjustment valve 12 obtained by adding the correction by the electrochemical reaction of the fuel cell stack 1 to the current gas pressure downstream of the hydrogen pressure adjustment valve 12 is a predetermined value. It is determined whether or not it is greater than or equal to P4. The correction process of the gas pressure downstream of the hydrogen pressure regulating valve 12 will be described later. In step S21, the controller 2 reads a sensor signal from a pressure sensor (not shown) that detects a gas pressure downstream of the hydrogen pressure regulating valve 12.

  If the controller 2 determines that the corrected gas pressure downstream of the hydrogen pressure adjustment valve 12 is not equal to or greater than the predetermined value P4, the controller 2 repeats this determination, and the corrected downstream gas pressure of the hydrogen pressure adjustment valve 12 is determined. If it is determined that the pressure is equal to or greater than the predetermined value P4, the process proceeds to step S4.

  Then, the controller 2 determines at time t25 that the operation of replacing the residual gas in the hydrogen electrode 1a with hydrogen gas has been completed in step S4, and starts supplying air to the air electrode 1b in step S5. Then, for example, the system shifts to normal power generation that supplies the amount of hydrogen and the amount of air corresponding to the required torque of the drive motor (FIGS. 8A and 8B).

“Correction of gas pressure downstream of hydrogen pressure regulating valve 12”
The correction process performed in step S21 is a hydrogen for determining whether or not the replacement with the hydrogen gas in the hydrogen electrode 1a is completed in consideration of the amount of hydrogen gas consumed by the electrochemical reaction in the hydrogen electrode 1a. The gas pressure downstream of the pressure regulating valve 12 is corrected.

  If the hydrogen gas pressure after step S1 is kept constant, if the hydrogen is not consumed by the electrochemical reaction, the molecular weight of the residual gas in the hydrogen electrode 1a is higher than the molecular weight of the hydrogen gas. There is less hydrogen supply. At this time, since the hydrogen electrode pressure is constant, when discharging heavy gas, it is necessary to reduce the amount of supplied hydrogen, and the gas pressure downstream of the hydrogen pressure regulating valve 12 has a characteristic F shown in FIG. As shown, the gas pressure downstream of the hydrogen pressure regulating valve 12 when the hydrogen electrode 1a is completely replaced with hydrogen gas changes to P4.

  On the other hand, when the hydrogen gas supplied by the electrochemical reaction is consumed, it is necessary to increase the amount of hydrogen gas supplied to the hydrogen electrode 1a in order to make the gas pressure in the hydrogen electrode 1a constant. The gas pressure downstream of the hydrogen pressure regulating valve 12 is larger than the characteristic F because it needs to be increased when an electrochemical reaction occurs, as shown by the characteristic E in FIG. The gas pressure downstream of the hydrogen pressure regulating valve 12 when 1a is completely replaced with hydrogen gas is P3 which is larger than P4.

  Therefore, when the predetermined value in step S21 is set to P4 without considering the amount of hydrogen consumed by the electrochemical reaction, the actual gas pressure downstream of the hydrogen pressure regulating valve 12 is shown in the characteristic E. In this example, the time t24 is earlier than the time t25 when it is determined that the replacement with hydrogen gas is completed.

  Therefore, the controller 2 of the fuel cell system according to the fifth embodiment estimates the hydrogen supply amount from the actual gas pressure downstream of the hydrogen pressure regulating valve 12 and also consumes the hydrogen consumed by the electrochemical reaction that does not contribute to the substitution. Is estimated from the generated current. Then, the controller 2 estimates the gas pressure downstream of the hydrogen pressure regulating valve 12 necessary for supplying the hydrogen amount obtained by subtracting the estimated consumed hydrogen amount from the estimated hydrogen supply amount to the hydrogen electrode 1a.

  Specifically, the controller 2 performs the same calculation as that of the second embodiment using the calculation formula shown in the above formula 1 for obtaining the volume flow rate that passes through the hydrogen pressure regulating valve 12, so that the corrected flow rate is obtained. The gas pressure downstream of the hydrogen pressure regulating valve 12 is obtained and compared with a predetermined value P4.

[Effect of Fifth Embodiment]
As described above in detail, according to the fuel cell system according to the fifth embodiment to which the present invention is applied, when the gas pressure of the hydrogen electrode 1a is kept constant at the time of system startup, the hydrogen electrode 1a turns into hydrogen gas. Since the gas pressure downstream of the hydrogen pressure regulating valve 12 that decreases as it is replaced is corrected in consideration of the amount of hydrogen consumed by the electrochemical reaction, it is possible to accurately determine the replacement of the hydrogen electrode 1a with hydrogen gas. it can.

[Sixth Embodiment]
Next, a fuel cell system according to the sixth embodiment will be described. Note that parts similar to those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fuel cell system according to the sixth embodiment, the generated water generated by the electrochemical reaction of the fuel cell stack 1 is included in the gas of the hydrogen electrode 1a, so that the density of hydrogen in the gas of the hydrogen electrode 1a is increased. Considering the change, it is different from the above-described embodiment in that it is determined whether the hydrogen electrode 1a is replaced with hydrogen gas.

  As described above, the volume flow rate of the gas passing through the hydrogen pressure regulating valve 12 and the purge valve 14 is expressed by Equation 1, but the gas volume flow rate changes when the gas density ρ0 changes. Here, the gas discharged from the fuel cell stack 1 contains water generated by an electrochemical reaction of the fuel cell stack 1 as water vapor, and remains due to the water vapor content of the gas discharged from the purge valve 14. Gas and hydrogen gas emissions are different. Further, the water vapor content of the gas discharged from the fuel cell stack 1 increases because the saturated water vapor pressure of the gas increases as the temperature of the fuel cell stack 1 increases.

  Therefore, in the fuel cell system according to the sixth embodiment, when the system is started with a constant hydrogen flow rate, the gas pressure P2 of the hydrogen electrode 1a that is determined to be replaced with the hydrogen gas of the hydrogen electrode 1a is set. to correct.

  That is, the controller 2 adds the amount of hydrogen consumed by the electrochemical reaction and the amount of hydrogen currently discharged from the purge valve 14 to the amount in the hydrogen electrode 1 a necessary for discharging from the purge valve 14. When estimating the pressure, the amount of hydrogen currently discharged from the purge valve 14 is corrected according to the temperature of the fuel cell stack 1. At this time, the controller 2 estimates the water vapor amount of the gas discharged from the hydrogen electrode 1a from the temperature value detected by the temperature sensor (not shown) of the fuel cell stack 1. Then, the controller 2 corrects the amount of hydrogen currently discharged from the purge valve 14 from the ratio of the molecular weight of hydrogen, the molecular weight of residual gas (air), and the molecular weight of water vapor, thereby correcting the corrected hydrogen amount and the electric power. The pressure in the hydrogen electrode 1a for discharging the amount of hydrogen added to the amount of hydrogen consumed by the chemical reaction from the purge valve 14 is corrected.

  According to such a fuel cell system, even if the gas discharged from the hydrogen electrode 1a is in a water vapor saturation state, the moisture concentration contained in the exhaust gas from the purge valve 14 increases as the temperature of the fuel cell stack 1 increases. And the gas pressure of the hydrogen electrode 1a that determines that the replacement of the hydrogen electrode 1a with hydrogen gas is completed is corrected, so that it can be determined that the hydrogen electrode 1a has been replaced with hydrogen gas more accurately. it can.

  Further, the fuel cell system according to the sixth embodiment has a hydrogen pressure regulating valve that determines that the replacement with the gas pressure of the hydrogen electrode 1a is completed when the system is started with the gas pressure of the hydrogen electrode 1a kept constant. The opening degree a2 of 12 is corrected.

  That is, the controller 2 requires the hydrogen pressure adjustment valve 12 required to supply the hydrogen electrode 1a with the hydrogen amount obtained by subtracting the hydrogen amount consumed from the hydrogen supply amount estimated from the actual opening of the hydrogen pressure adjustment valve 12. When the opening degree a2 is estimated, the hydrogen supply amount estimated from the actual opening degree of the hydrogen pressure regulating valve 12 is corrected based on the water vapor amount determined by the temperature of the fuel cell stack 1. Thereby, the controller 2 corrects the opening a2 of the hydrogen pressure regulating valve 12 from the hydrogen supply amount corrected based on the water vapor amount and the hydrogen amount consumed by the electrochemical reaction.

  According to such a fuel cell system, even when the gas discharged from the hydrogen electrode 1a is saturated with water vapor and the amount of hydrogen supplied to the hydrogen electrode 1a changes, the amount of water vapor in the hydrogen electrode 1a Since the opening of the hydrogen pressure regulating valve 12 is corrected based on the above, it can be determined that the hydrogen electrode 1a has been replaced with hydrogen gas more accurately.

  Further, in the fuel cell system according to the sixth embodiment, the hydrogen electrode 1a is replaced with hydrogen gas when the system is started with the gas pressure between the hydrogen pressure regulating valve 12 and the ejector pump 31 kept constant. When the gas pressure between the pressure control valve 12 and the ejector pump 31 is increased as the travel proceeds, the gas pressure between the pressure control valve 12 and the ejector pump 31 is corrected by the amount of water vapor in the hydrogen electrode 1a. As a result, the fuel cell system can more accurately determine that the hydrogen electrode 1a has been replaced with hydrogen gas.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

It is a block diagram which shows the structure of the fuel cell system which concerns on 1st Embodiment to which this invention is applied. It is a flowchart which shows the process sequence of the starting process of the fuel cell system which concerns on 1st Embodiment to which this invention is applied. It is a figure explaining operation | movement when the starting process of the fuel cell system which concerns on 1st Embodiment to which this invention is applied is performed, (a) is an air flow rate, (b) is a hydrogen flow rate, (c) is electric power generation. Voltage, (d) shows the generated current, and (e) shows the gas pressure at the hydrogen electrode. It is a flowchart which shows the process sequence of the starting process of the fuel cell system which concerns on 2nd Embodiment to which this invention is applied. It is a figure explaining operation | movement when the starting process of the fuel cell system which concerns on 2nd Embodiment to which this invention is applied is performed, (a) is an air flow rate, (b) is a hydrogen flow rate, (c) is electric power generation. Voltage, (d) indicates the generated current, and (e) indicates the opening of the hydrogen pressure regulating valve. It is a block diagram which shows the structure of the fuel cell system which concerns on 3rd Embodiment to which this invention is applied. It is a flowchart which shows the process sequence of the starting process of the fuel cell system which concerns on 5th Embodiment to which this invention is applied. It is a figure explaining operation | movement when the starting process of the fuel cell system which concerns on 5th Embodiment to which this invention is applied is performed, (a) is an air flow rate, (b) is a hydrogen flow rate, (c) is electric power generation. Voltage, (d) indicates the generated current, and (e) indicates the gas pressure between the hydrogen pressure regulating valve and the ejector pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 2 Controller 3 Voltage sensor 4 Preliminary load 11 Hydrogen cylinder 12 Hydrogen pressure regulating valve 13, 15, 23 Actuator 14 Purge valve 21 Compressor 22 Air pressure regulating valve 31 Ejector pump L1 Hydrogen supply flow path L2 Hydrogen discharge flow path L3 Air Supply flow path L4 Air discharge flow path L11 Hydrogen circulation flow path

Claims (9)

A fuel cell that generates fuel by supplying fuel gas to the fuel electrode and supplying oxidant gas to the oxidant electrode; and
Fuel gas is supplied to the fuel electrode of the fuel cell via a fuel gas supply channel connected to the fuel gas inlet of the fuel cell, and via a fuel gas discharge channel connected to the fuel gas outlet of the fuel cell. Fuel gas supply means for discharging the fuel gas discharged from the fuel cell;
An oxidant gas is supplied to an oxidant gas electrode of the fuel cell via an oxidant gas supply channel connected to an oxidant gas inlet of the fuel cell, and an oxidant connected to an oxidant gas outlet of the fuel cell. An oxidant gas supply means for discharging the oxidant gas discharged from the fuel cell through the oxidant gas discharge channel;
Power consumption means for adjusting the power generation voltage of the fuel cell by consuming the power generated by the fuel cell;
Power generation voltage detection means for detecting the power generation voltage of the fuel cell;
At the time of starting the system, the fuel gas supply means is controlled to supply the fuel gas to the fuel electrode without supplying the oxidant gas to the oxidant electrode, and it is determined that the fuel electrode has been replaced by the fuel gas. And a start control means for consuming the generated voltage by the power consuming means so that the generated voltage of the fuel cell detected by the generated voltage detecting means is below a predetermined value. The fuel gas supply means is provided with a variable throttle valve for adjusting a flow rate of the fuel gas flowing through the fuel gas supply flow path,
The activation control means adjusts the opening of the variable throttle valve so that the flow rate of the fuel gas supplied to the fuel electrode is constant, and the actual gas pressure of the fuel electrode is consumed by the electrochemical reaction of the fuel cell. 2. The fuel cell system according to claim 1, wherein the fuel electrode is determined to have been replaced with a fuel gas when the gas pressure correction value is equal to or less than a predetermined value. . The fuel gas supply means is provided with a variable throttle valve for adjusting a flow rate of the fuel gas flowing through the fuel gas supply flow path,
The activation control means adjusts the actual opening of the variable throttle valve to the electric power of the fuel cell when the opening of the variable throttle valve is adjusted so that the fuel gas pressure supplied to the fuel electrode is constant. The correction is made based on the amount of hydrogen consumed by the chemical reaction, and when the opening correction value is equal to or greater than a predetermined value, it is determined that the fuel electrode is replaced by fuel gas. The fuel cell system described. The fuel gas supply means includes a variable throttle valve that adjusts the flow rate of the fuel gas flowing through the fuel gas supply flow path, and an ejector pump that circulates the fuel gas discharged from the fuel cell to the fuel gas supply flow path. ,
The activation control means adjusts the opening of the variable throttle valve so that the flow rate of the fuel gas supplied to the fuel electrode is constant, and the actual gas pressure of the fuel electrode is consumed by the electrochemical reaction of the fuel cell. 2. The fuel cell system according to claim 1, wherein the fuel electrode is determined to have been replaced with a fuel gas when the gas pressure correction value is equal to or less than a predetermined value. . The fuel gas supply means includes a variable throttle valve that adjusts the flow rate of the fuel gas flowing through the fuel gas supply flow path, and an ejector pump that circulates the fuel gas discharged from the fuel cell to the fuel gas supply flow path. ,
The activation control means adjusts the actual opening of the variable throttle valve to the electric power of the fuel cell when the opening of the variable throttle valve is adjusted so that the fuel gas pressure supplied to the fuel electrode is constant. The correction is made based on the amount of hydrogen consumed by the chemical reaction, and when the opening correction value is equal to or greater than a predetermined value, it is determined that the fuel electrode is replaced by fuel gas. The fuel cell system described. The fuel gas supply means is provided on a downstream side of the variable throttle valve for adjusting a flow rate of the fuel gas flowing in the fuel gas supply flow path, and the fuel gas discharged from the fuel cell is supplied to the fuel. With an ejector pump that circulates in the gas supply flow path,
The start control means adjusts the opening of the variable throttle valve so that the fuel gas pressure supplied to the fuel electrode is constant, and the actual gas between the variable throttle valve and the ejector pump Correcting the pressure based on the amount of hydrogen consumed by the electrochemical reaction of the fuel cell, and determining that the fuel electrode has been replaced by the fuel gas when the gas pressure correction value exceeds a predetermined value. The fuel cell system according to claim 1, wherein   5. The fuel cell system according to claim 2, wherein the activation control unit corrects the gas pressure of the fuel electrode based on a temperature of the fuel cell.   6. The fuel cell system according to claim 3, wherein the activation control unit corrects the opening of the variable throttle valve based on a temperature of the fuel cell. The fuel cell system according to claim 6, wherein the activation control unit corrects a gas pressure between the variable throttle valve and the ejector pump based on a temperature of the fuel cell.

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