JP2019129089A - Fuel cell system - Google Patents

Abstract

To reduce a crosstalk occurring due to a difference in hydrogen gas pressure between an anode 12 and a cathode 13.SOLUTION: A fuel cell system comprises: a circulation pump 82 for mixing an exhaust gas discharged from an anode 12 that contains a hydrogen gas with a hydrogen gas from an injection 80 and supplying the mixture to the anode 12 for circulation of the exhaust gas; and an air compressor 84 for supplying a compressed air to a cathode 13. When power generation by a fuel cell 10 is not requested, a control unit 90 generates power by the fuel cell 10 when it is determined in a step S120 that the hydrogen partial pressure in the anode 12 is greater than or equal to a threshold and controls a converter 40 so that a battery 50 is charged with the generated power. This way, it is possible to reduce the hydrogen partial pressure quickly by power generation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  Conventionally, in a fuel cell system, a fuel cell including a single cell having an anode and a cathode, a hydrogen supply device for supplying hydrogen gas to the anode, and hydrogen discharged from the anode without being used for power generation of the fuel cell are included. And a circulation pump for supplying the anode exhaust gas to the anode again to circulate the anode exhaust gas (see, for example, Patent Document 1).

  The control unit has a total hydrogen loss amount that is a sum of a hydrogen amount corresponding to electric power necessary for driving the circulation pump and a hydrogen amount passing from the anode side to the cathode side of the fuel cell at a predetermined current value. The circulation pump is driven so that the rotation speed approaches the optimum rotation speed of the circulation pump that is minimized.

  Thus, in order to avoid deterioration in fuel consumption, instead of increasing the hydrogen partial pressure in the anode, the circulation pump is driven to ensure a stoichiometric ratio and suppress cross-leakage of hydrogen gas passing from the anode to the cathode.

JP, 2016-96085, A

  However, in the fuel cell system, when water or nitrogen generated by power generation of the fuel cell is discharged from the exhaust valve, the anode is supplied by supplying hydrogen from the hydrogen supply device to the anode so that the air does not flow backward to the anode through the exhaust valve. The internal gas pressure needs to be higher than atmospheric pressure. As a result, the hydrogen concentration in the anode increases.

  Also, at high loads where high power generation is required, the amount of hydrogen supplied to the anode increases and the gas pressure in the anode increases, so that the hydrogen concentration in the anode remains high even after the power generation request is lost. May continue.

  As described above, when the hydrogen concentration is high in the non-power generation state, the hydrogen partial pressure in the anode can not be reduced, and the cross leak of hydrogen gas can not be suppressed.

  An object of the present invention is to provide a fuel cell system in which cross leak of hydrogen gas is suppressed.

In order to achieve the above object, in the invention according to claim 1, a fuel cell (10) having a single cell (10a) comprising a fuel electrode (12) and an oxygen electrode (11),
A hydrogen supply unit (80) for supplying hydrogen gas to the fuel electrode;
A circulation pump (82) for mixing exhaust gas containing hydrogen gas exhausted from the fuel electrode without being used for fuel cell power generation with hydrogen gas from the hydrogen supply unit and supplying it to the fuel electrode to circulate the exhaust gas;
An oxidant supply unit (84) for supplying an oxidant to the oxygen electrode;
A first power output unit (30) for outputting electric power generated by the fuel cell using hydrogen gas and an oxidant to an electric load (20);
A second power output unit (40) for charging the battery (50) with electric power generated by the fuel cell using hydrogen gas and an oxidant;
A first power generation control unit (S140) for controlling the first power output unit to generate power by the fuel cell and output the generated power to the electric load when power generation by the fuel cell is required;
A hydrogen partial pressure detection unit (91) for detecting a hydrogen gas partial pressure in the fuel electrode;
A first hydrogen partial pressure determination unit (S120) for determining whether or not the detection value of the hydrogen partial pressure detection unit is higher than a threshold value (Pth);
When the first hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is higher than the threshold when power generation by the fuel cell is not required, the fuel cell generates electricity, and the generated power is used as a battery A second power generation control unit (S130) that controls the second power output unit so as to be charged.

  Therefore, since the hydrogen gas concentration in the fuel electrode can be lowered by the power generation of the fuel cell, the hydrogen gas partial pressure in the fuel electrode can be lowered. Therefore, it is possible to provide a fuel cell system that suppresses cross leak in which hydrogen gas passes from the fuel electrode side to the oxygen electrode side.

  In addition, the code | symbol in the parenthesis of each means described by this column and the claim shows correspondence with the specific means as described in embodiment mentioned later.

1 is a diagram illustrating an overall configuration of a fuel cell system according to a first embodiment of the present invention. It is for demonstrating the subject of the fuel cell system in 1st Embodiment, and is a timing chart of gas total pressure in the anode at the time of non-electric power generation after exhaust_gas | exhaustion, and hydrogen gas partial pressure. It is for demonstrating the subject of the fuel cell system in 1st Embodiment, and is a timing chart of gas total pressure in the anode at the time of non-electric power generation after high load, and hydrogen gas partial pressure. It is a flowchart which shows the detail of the control processing in the control part of FIG. It is a flowchart which shows the detail of the control processing in the fuel cell system in 2nd Embodiment of this invention. It is a figure which shows the whole structure of the fuel cell system in 3rd Embodiment of this invention. It is a figure which shows the whole structure of the fuel cell system in 4th Embodiment of this invention. It is a figure which shows the whole structure of the fuel cell system in 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts identical or equivalent to each other are denoted by the same reference numerals in the drawings in order to simplify the description.

First Embodiment
Hereinafter, a fuel cell system according to a first embodiment of the present invention will be described based on the drawings.

  The fuel cell system of the present embodiment is applied to a fuel cell vehicle which is a type of electric vehicle, and controls the power generation state of the fuel cell 10 mounted on the vehicle.

  The fuel cell 10 outputs electric energy using an electrochemical reaction of a reaction gas such as a fuel gas containing hydrogen gas and an oxidant gas (air in this example) containing oxygen gas. In the present embodiment, a solid polymer fuel cell is employed as the fuel cell 10.

  The fuel cell 10 mainly supplies DC power generated by power generation to an electric load 20 such as a vehicle travel electric motor or a secondary battery through an inverter 30.

  The fuel cell 10 of the present embodiment has a stack structure in which a plurality of cells 10a serving as a minimum unit are stacked, and is configured as a series connection body in which a plurality of cells 10a are electrically connected in series.

  As shown in FIG. 1, the plurality of cells 10 a are disposed on the electrolyte membrane 11, the cathode (that is, the oxygen electrode) 13 disposed on one surface of the electrolyte membrane 11, and the other surface of the electrolyte membrane 11. A membrane electrode assembly having an anode (ie, fuel electrode) 12. In FIG. 1, one single cell 10 a is shown as the fuel cell 10.

  The electrolyte membrane 11 is a solid polymer electrolyte membrane that exhibits good proton conductivity in a wet state, and is made of, for example, a fluorine-based ion exchange resin. The cathode 13 and the anode 12 are electrodes having gas diffusibility and conductivity, and each include a catalyst electrode layer and a gas flow path facing the catalyst electrode layer.

  The catalyst electrode layer includes a catalyst metal that proceeds with an electrochemical reaction and a polymer electrolyte having proton conductivity. The catalyst electrode layer is formed, for example, as a dried coating film of a catalyst ink in which platinum supported carbon and a polymer electrolyte which is the same as or similar to the electrolyte membrane 11 are dispersed in a solvent. The gas flow path is formed by, for example, a not-shown separator groove or expanded metal. Here, the gas flow channel of the cathode 13 is also referred to as a cathode gas flow channel 13a, and the gas flow channel of the anode 12 is also referred to as an anode gas flow channel 12a.

  When the fuel gas is supplied to the anode gas flow path 12a and the air as the oxidant gas is supplied to the cathode gas flow path 13a, the plurality of cells 10a are each supplied with hydrogen gas and oxygen gas as shown below. Output electrical energy by the electrochemical reaction of

(Anode side) H ₂ → 2 H ⁺ + 2 e ⁻
(Cathode side) 2H ⁺ + 1 / 2O ² + 2e ⁻ → H ₂ O
The fuel cell 10 configured in this manner outputs a voltage obtained by adding the output voltages of the plurality of cells 10a as the output voltage Vn. An electric load 20 is connected to the fuel cell 10 via an inverter 30. Each of the plurality of cells 10a of the present embodiment is configured to be cooled by cooling water.

  The inverter 30 is a first power output unit which is controlled by the control unit 90 and causes an alternating current to flow to the electric load 20 based on the output voltage of the fuel cell 10 (or the output voltage of the converter 40). A battery 50 is connected to the fuel cell 10 via a converter 40.

  As the battery 50 of the present embodiment, a secondary battery such as a lithium ion battery or a lead storage battery or a capacitor is used.

  The fuel cell system includes a fuel supply pipe 60, an anode discharge pipe 61, an exhaust drainage pipe 62, an air supply pipe 63, and a cathode exhaust pipe 64.

  The fuel supply pipe 60 supplies the hydrogen gas from the hydrogen tank 70 to the anode gas flow paths 12a of the plurality of cells 10a. An injection 80 as a hydrogen supply unit is disposed between the hydrogen gas outlet of the hydrogen tank 70 and the hydrogen gas inlet 10 b of the fuel cell 10.

  The injection 80 adjusts the flow rate of hydrogen gas flowing in the hydrogen gas flow path between the hydrogen gas outlet of the hydrogen tank 70 and the hydrogen gas inlet 10 b of the fuel cell 10. The hydrogen gas inlet 10b of the fuel cell 10 is in communication with the hydrogen gas inlet of the anode gas flow passage 12a of each cell 10a.

  Specifically, the injection 80 includes a valve body that opens and closes a hydrogen gas flow path, and an electric actuator that drives the valve body.

  Here, a period in which the hydrogen gas flow rate is closed by the injection 80 is a closing period Tc, a period in which the hydrogen gas flow rate is opened by the injection 80 is an opening period To, and a period Tk (= Tc + To) obtained by adding the closing period Tc and the opening period To. Is one cycle. A value obtained by dividing the open period To by the open period To is defined as a duty ratio dy (= To / Tk).

  By increasing the duty ratio dy of the injection 80, the flow rate of hydrogen gas flowing through the hydrogen gas flow path increases. On the other hand, by reducing the duty ratio dy of the injection 80, the flow rate of hydrogen gas flowing through the hydrogen gas flow path is reduced.

  The gas inlet of the anode discharge pipe 61 is connected to the anode gas outlet 10 c of the fuel cell 10. The gas outlet of the anode discharge pipe 61 is connected to a portion 60 a of the fuel supply pipe 60 between the hydrogen gas outlet of the injection 80 and the hydrogen gas inlet of the fuel cell 10.

  A gas-liquid separator 81 and a circulation pump 82 are disposed in the anode discharge pipe 61. The gas-liquid separator 81 separates nitrogen gas, water and hydrogen gas contained in the anode exhaust gas discharged from the anode gas outlet 10c of the fuel cell 10, and guides the separated hydrogen gas to the fuel supply pipe 60. Water and nitrogen gas are guided to the exhaust drainage pipe 62.

  Here, the hydrogen gas separated by the gas-liquid separator 81 is hydrogen gas discharged from the anode discharge pipe 61 without being used for power generation of the fuel cell 10 (hereinafter referred to as unused hydrogen gas). The anode gas outlet 10c communicates with the outlet of the anode gas flow path 12a for each cell 10a.

  The exhaust drain pipe 62 discharges moisture, nitrogen gas, and the like induced by the gas-liquid separator 81 to the atmosphere. An exhaust / drain valve 83 is provided in the exhaust / drain pipe 62. The exhaust / drain valve 83 includes a valve body that opens and closes the exhaust / drain pipe 62 and an electric actuator that drives the valve body.

  The circulation pump 82 is an electric pump that circulates the hydrogen gas by mixing the hydrogen gas derived from the gas-liquid separator 81 with the hydrogen gas from the hydrogen tank 70 and supplying it to the anode gas flow path 12a.

  That is, the circulation pump 82 mixes the exhaust gas containing the unused hydrogen gas flowing from the anode discharge pipe 61 without being used for the power generation of the fuel cell 10 with the hydrogen gas from the hydrogen tank 70 and supplies it to the anode gas flow path 12a. Thus, the exhaust gas is circulated. The circulation pump 82 of the present embodiment adjusts the flow rate of gas circulated between the gas-liquid separator 81 and the anode gas flow passage 12 a.

  The air supply pipe 63 supplies the air flow (i.e., oxygen gas) to the air inlet 10 d of the fuel cell 10 with the air flow pumped by the air compressor 84. The air inlet 10d of the fuel cell 10 communicates with the inlet of the cathode gas flow path for each cell 10a.

  The air compressor 84 is an oxidant supply unit which is controlled by the control unit 90 and adjusts the amount of air supplied to the air inlet 10 d of the fuel cell 10 via the air supply pipe 63.

  The cathode exhaust pipe 64 discharges the air flow discharged from the air outlet 10e of the fuel cell 10 to the atmosphere. The air outlet 10e of the fuel cell 10 is in communication with the air outlet of the cathode gas flow path 13a of each cell 10a.

  Next, the electrical configuration of the fuel cell system of this embodiment will be described.

  The fuel cell system includes a control unit 90. The control unit 90 includes a microcomputer, a memory, and the like, and executes power generation control processing according to a computer program stored in advance in the memory.

  The power generation control process is a control process for controlling the power generation amount of the fuel cell 10 or reducing the hydrogen gas partial pressure in the anode gas passage 12a for each cell 10a of the fuel cell 10.

  In accordance with the execution of the power generation control process, the control unit 90 generates the inverter 30 and the converter based on the detection signals of the temperature sensors 91b and 11a, the detection signal of the hydrogen partial pressure detection unit 91, the detection signal of the accelerator pedal position sensor 92, and the like. 40, the exhaust drain valve 83, the circulation pump 82, the injection 80, and the air compressor 84 are controlled.

  The hydrogen partial pressure detection unit 91 is a hydrogen partial pressure detection unit that detects the hydrogen gas partial pressure in the anode gas flow channel 12a of each cell 10a. The hydrogen partial pressure detector 91 of the present embodiment detects the hydrogen gas partial pressure in the anode exhaust gas discharged from the exhaust gas outlet 10c of the fuel cell 10 (that is, the anode gas flow path 12a for each cell 10a).

  The temperature sensor 91 b is a temperature sensor that detects the temperature of the anode exhaust gas discharged from the exhaust gas outlet 10 c of the fuel cell 10. The temperature sensor 11 a is a temperature sensor that detects the temperature of the fuel cell 10. For example, a water temperature sensor that detects the temperature of the cooling water of the fuel cell 10 may be used as the temperature sensor 11a.

  The accelerator pedal position sensor 92 detects the position of the accelerator pedal (that is, the depression amount of the accelerator pedal) which is depressed by the driver's foot.

  The converter 40 is a second power output unit that is controlled by the control unit 90 to boost the output voltage of the fuel cell 10 and output the boosted voltage to the battery 50, or to step down the output voltage of the battery 50 and output it to the inverter 30. .

  Next, the fuel cell system of this embodiment will be described with reference to FIGS.

  First, the control unit 90 controls the circulation pump 82, the injection 80, and the air compressor 84 based on the detection signal of the accelerator pedal position sensor 92, supplies hydrogen gas to the anode gas flow path 12a, and cathode gas. Air is supplied to the flow path 13a.

  As the amount of depression of the accelerator pedal by the driver increases, the duty ratio dy of the injection 80 is increased to increase the flow rate of hydrogen gas flowing from the hydrogen tank 70 to the fuel cell 10.

  As the amount of depression of the accelerator pedal by the driver increases, the number of revolutions of the circulation pump 82 is increased to increase the circulation amount of hydrogen gas between the anode gas flow path 12a and the gas-liquid separator 81 for each cell 10a. .

  On the other hand, the smaller the depression amount of the accelerator pedal by the driver, the smaller the duty ratio dy of the injection 80 and the lower the flow rate of hydrogen gas flowing from the hydrogen tank 70 to the fuel cell 10.

  As the amount of depression of the accelerator pedal by the driver is reduced, the number of revolutions of the circulation pump 82 is reduced to reduce the amount of hydrogen gas circulated between the anode gas passage 12a and the gas-liquid separator 81 for each cell 10a. .

  Therefore, as the depression amount of the accelerator pedal increases, the amount of hydrogen gas supplied to the anode gas flow path 12a for each cell 10a increases. As the depression amount of the accelerator pedal decreases, the amount of hydrogen gas supplied to the anode gas flow path 12a for each cell 10a decreases.

  As the driver's depression amount of the accelerator pedal increases, the rotational speed of the air compressor 84 is increased, and the amount of air supplied to the air supply pipe 63 is increased. On the other hand, as the depression amount of the accelerator pedal by the driver decreases, the rotational speed of the air compressor 84 is increased, and the amount of air supplied to the air supply pipe 63 is decreased.

  The inverter 30 causes the control unit 90 to flow an alternating current to the electric load 20 based on the output voltage Va of the fuel cell 10.

  Here, as the amount of depression of the accelerator pedal by the driver increases, the above-described electrochemical reaction of hydrogen gas and oxygen gas is promoted, and large electric energy is output from the fuel cell 10.

  Accordingly, the AC power supplied from the fuel cell 10 to the electric load 20 through the inverter 30 is increased.

  As the amount of depression of the accelerator pedal by the driver decreases, the above-described electrochemical reaction of hydrogen gas and oxygen gas is suppressed, and the electrical energy output from the fuel cell 10 decreases. Accordingly, the AC power supplied from the fuel cell 10 to the electric load 20 through the inverter 30 is reduced.

  Here, if the power generation of the fuel cell 10 is continued, the nitrogen gas in the anode gas passage 12a is caused by the cross leak in which the nitrogen gas in the air in the cathode gas passage 13a moves to the anode gas passage 12a. The concentration of increases.

  On the other hand, in the present embodiment, the control unit 90 opens the exhaust / drain valve 83 at regular intervals. Therefore, nitrogen gas, water and the like flowing through the anode discharge pipe 61 are discharged from the gas-liquid separator 81 to the atmosphere through the exhaust / drain pipe 62 and the exhaust / drain valve 83.

  At this time, in order to prevent air from flowing back from the atmosphere to the exhaust / drain pipe 62 through the exhaust / drain valve 83, the duty ratio dy of the injection 80 is increased and the rotational speed of the circulation pump 82 is increased. For this reason, the amount of hydrogen gas supplied to the anode gas flow path 12a for each cell 10a increases. Thereby, the hydrogen gas concentration in the anode gas flow path 12a for every cell 10a becomes high (refer FIG. 2).

  Further, when a high load operation is performed in which the amount of depression of the accelerator pedal by the driver is increased, the hydrogen concentration in the anode gas flow path 12a of each cell 10a becomes excessively high (see FIG. 3).

  As described above, when the hydrogen gas concentration in the anode gas flow path 12a of each cell 10a becomes excessively high due to high load operation or nitrogen gas discharge, the hydrogen gas partial pressure in the anode gas flow path 12a becomes excessively high. To rise. As a result, there is a possibility that a cross leak may occur in which the hydrogen gas moves from the anode gas flow passage 12a to the cathode gas flow passage 13a.

  On the other hand, in the present embodiment, the control unit 90 executes the power generation control process to reduce the hydrogen gas concentration in the anode gas flow passage 12a for each cell 10a. Hereinafter, the details of the power generation control process by the control unit 90 will be described. The controller 90 executes power generation control processing according to the flowchart of FIG.

  First, in step S100, the controller 90 controls the duty ratio dy of the injection 80 such that the amount of hydrogen gas supplied from the hydrogen tank 70 to the fuel cell 10 becomes a predetermined amount.

  In addition, in step S100, the control unit 90 causes the circulation pump 82 so that the gas circulation amount circulated between the anode gas flow path 12a and the gas-liquid separator 81 for each cell 10a becomes a predetermined amount. Control the number of revolutions.

  Furthermore, in step S100, the control unit 90 controls the air compressor 84 such that the amount of air supplied to the cathode gas flow path 13a for each cell 10a becomes a predetermined amount.

  Next, the control unit 90 determines whether or not there is a power generation request from the driver to the fuel cell 10 in step S110.

  For example, if the accelerator pedal is not depressed by the driver and the accelerator pedal depression amount Fa is zero (depression amount Fa = zero), NO is determined in step S100 that there is no power generation request from the driver to the fuel cell 10. judge.

Next, in step S120, it determines a first hydrogen partial pressure determining unit, whether or not the hydrogen gas partial pressure PH ₂ detected by the hydrogen partial pressure detector 91 is greater than the threshold value Pth.

At this time, when the hydrogen gas partial pressure PH ₂ detected by the hydrogen partial pressure detector 91 is greater than the threshold value Pth, the control unit 90 determines YES in step S120.

  Along with this, in step S130, the control unit 90 causes the fuel cell 10 to generate power as the second power generation control unit and causes the battery 50 to charge the generated power.

  Specifically, the injection 80 is controlled to close the hydrogen flow path between the hydrogen outlet of the hydrogen tank 70 and the hydrogen inlet of the fuel cell 10.

  At this time, the operation of the circulation pump 82 circulates hydrogen gas between the gas-liquid separator 81 and the anode gas flow path 12a, and the operation of the air compressor 84 supplies an air flow to the air inlet of the fuel cell 10. The

  For this reason, the electrochemical reaction of hydrogen gas and oxygen gas is promoted, and electric energy is output from the fuel cell 10.

  At this time, the converter 40 is controlled by the control unit 90 to boost the output voltage of the fuel cell 10 and output it to the battery 50. That is, converter 40 absorbs the electric energy generated by fuel cell 10 and outputs it to battery 50. As a result, power generation by the fuel cell 10 is promoted, and the generated power is charged in the battery 50.

  Then, it returns to step S110. Therefore, the control unit 90 determines whether or not there is a power generation request from the driver to the fuel cell 10.

Therefore, there is no power demand for the fuel cell 10 from the driver, and the hydrogen gas partial pressure PH ₂ detected by the hydrogen partial pressure detector 91 state continues greater than the threshold value Pth, control unit 90 , NO determination in step S110, YES determination in step S120, and step S130 (FC power generation / battery charging) are repeated.

  As a result, the hydrogen gas concentration in the anode gas flow path 12a of each cell 10a can be reduced.

Thereafter, the hydrogen gas partial pressure PH ₂ to be detected is smaller than the threshold value Pth by the hydrogen partial pressure detector 91. In other words, the power generation of the fuel cell 10 is continued and the battery 50 is charged until the hydrogen gas partial pressure PH < _b > ₂ is excessively high at the time of non-power generation until it becomes equal to that at the steady state. Along with this, the control unit 90 determines NO in step S120.

Here, the volume of the hydrogen gas flow path is V [L], the temperature is T [K], the gas constant is R, and the hydrogen gas partial pressure PH ₂ at the steady state is the hydrogen gas partial pressure PH ₂ norm [kPa]. And the hydrogen gas partial pressure PH ₂ that has risen transiently is defined as the hydrogen partial pressure PH ₂ trans [kPa].

In step S130, energy of V × (PH ₂ trans−PH ₂ norm) / (R × T) × 241.83 kJ will be used for power generation. The hydrogen gas flow path of this embodiment is the anode gas flow path 12a for each cell 10a. “241.83 kJ” is the lower hydrogen heating value “kJ / mol”. Thereafter, the process returns to step S110.

  At this time, if the accelerator pedal is depressed by the driver's foot and the accelerator pedal depression amount Fa is greater than or equal to zero (depression amount Fa> zero), it is assumed that there is a power generation request from the driver to the fuel cell 10 in step S100. Is determined as YES.

  Along with this, in step S140, as a first power generation control unit, the inverter 30 and the converter 40 are controlled so that the output of the battery 50 is given priority to the electric load 20 over the output of the fuel cell 10.

  Specifically, converter 40 is controlled by control unit 90 to step down the output voltage of battery 50 to a predetermined output pressure and output it to inverter 30. The predetermined voltage is a value determined in advance and set to a voltage higher than the output voltage of the fuel cell 10.

  In addition to this, the inverter 30 is controlled by the control unit 90 to flow an alternating current to the electric load 20 based on the output voltage of the converter 40. As a result, in a state where the power generation of the fuel cell 10 is suppressed, the direct current power charged in the battery 50 is converted into alternating current power and is given to the electric load 20.

  Thereafter, converter 40 is controlled by control unit 90 to stop the step-down operation. Along with this, the inverter 30 is controlled by the control unit 90 to cause an alternating current to flow to the electric load 20 based on the output voltage of the fuel cell 10.

  That is, the inverter 30 absorbs the electric energy generated by the fuel cell 10 and outputs it to the electric load 20. As a result, power generation by the fuel cell 10 is promoted, and the generated DC power is converted into AC power and is given to the electrical load 20. As a result, the output of the battery 50 is output to the electric load 20 with priority over the output of the fuel cell 10.

  According to the present embodiment described above, the fuel cell system includes a fuel cell 10 including a plurality of single cells 10 a including the anode 12 and the cathode 13, and an injection 80 for supplying hydrogen gas from the hydrogen tank 70 to the anode 12. With.

  The fuel cell system is a circulation pump 82 that circulates exhaust gas by mixing exhaust gas containing hydrogen gas discharged from the anode 12 without being used for power generation of the fuel cell 10 with hydrogen gas from the injection 80 and supplying the mixed gas to the anode 12. And an air compressor 84 for supplying an air flow as an oxidant to the cathode 13.

  The fuel cell system includes an inverter 30 that converts electric power generated by hydrogen gas and air in the fuel cell 10 into AC power and outputs the alternating current power, and electric power generated by hydrogen gas and air in the fuel cell 10. And a converter 40 for charging the battery 50.

  When power generation by the fuel cell 10 is required, the fuel cell system includes a step S140 for controlling the inverter 30 so that the fuel cell 10 generates power and outputs the generated power to the electric load 20.

  In the fuel cell system, when power generation by the fuel cell 10 is not required, the control unit 90 causes the fuel cell 10 to generate power when it is determined in step S120 that the hydrogen partial pressure in the anode 12 is equal to or higher than the threshold value Pth. Step S130 for controlling the converter 40 so as to charge the battery 50 with the generated electric power is provided.

  Thereby, the hydrogen gas partial pressure can be quickly reduced by power generation. For this reason, the cross leak from which hydrogen gas moves from the anode 12 side to the cathode 13 side can be suppressed.

  In the present embodiment, when power generation by the fuel cell 10 is required, the inverter 30 and the converter 40 are controlled so that the power from the battery 50 is output to the electric load 20 with priority over the power from the fuel cell 10. To do.

  As a result, even when a large amount of power is required to be generated by the fuel cell 10, the power from the battery 50 is given priority over the power from the fuel cell 10 and is output to the electric load 20. As a result, it is possible to suppress the occurrence of hydrogen gas deficiency and to balance the charging / discharging of the battery 50 so that the control of the fuel cell system is established.

Second Embodiment
In the second embodiment, in the first embodiment, when the hydrogen gas partial pressure PH ₂ is less than the threshold value Pth is optionally 5 for example of supplying hydrogen gas from the hydrogen tank 70 to the anode 12 Explain with reference to.

  This embodiment is different from the first embodiment in part of the power generation control processing by the control unit 90. Thus, hereinafter, differences in power generation control processing between the present embodiment and the first embodiment will be mainly described.

  The power generation control process performed by the control unit 90 of the present embodiment uses the flowchart of FIG. 5 instead of FIG. The flowchart of FIG. 5 is obtained by adding steps S150, S160, S170, and S180 to the flowchart of FIG. In the flowchart of FIG. 5, the same reference numerals as those in the flowchart of FIG. 4 indicate the same steps, and thus the description thereof is simplified.

  Hereinafter, the details of the power generation control process by the control unit 90 of the present embodiment will be described.

  The controller 90 executes power generation control processing according to the flowchart of FIG.

  First, the control unit 90 controls the injection 80, the circulation pump 82, and the air compressor 84 in step S100.

  Next, in step S100, when the accelerator pedal is not depressed by the driver and the accelerator pedal depression amount Fa is zero, it is determined that the driver does not have a power generation request to the fuel cell 10 and NO is determined.

Next, in step S120, when the hydrogen gas partial pressure PH ₂ detected by the hydrogen partial pressure detector 91 is greater than the threshold value Pth, the control unit 90 determines YES in step S120.

  Accordingly, the control unit 90 causes the fuel cell 10 to generate power and charge the battery 50 in step S130.

Then, the process returns to step S110, there is no power demand for the fuel cell 10 from the driver, and the partial pressure of hydrogen gas PH ₂ status is continued greater than the threshold value Pth, control unit 90, NO in step S110 The determination, YES determination in step S120, and step S130 (FC power generation / battery charging) are repeated.

Thereafter, the hydrogen gas partial pressure PH ₂ is less than the threshold value Pth, control unit 90 determines NO in step S120.

Next, the control unit 90, at step S150, the determining whether the hydrogen gas partial pressure PH ₂ is greater than the lower limit target value PL. Here, the lower limit target value PL is a lower limit value of the hydrogen gas partial pressure for preventing deterioration of the anode 12 due to lack of hydrogen gas. The lower limit target value PL is set to a value smaller than the threshold value Pth (> PL).

At this time, when the hydrogen gas partial pressure PH ₂ is greater than the lower limit target value PL, the control unit 90 determines that YES in step S150.

As a result, in step S130, power generation is performed using a hydrogen gas amount equal to or less than the hydrogen gas amount corresponding to the difference ΔP (= PH ₂ −PL) between the hydrogen gas partial pressure PH ₂ and the lower limit target value PL. .

Next, in step S160, the control unit 90, the amount of hydrogen gas to migrate from the anode 12 to the cathode 13 based on the hydrogen gas partial pressure PH ₂ (hereinafter, referred to as cross leakage amount Qc) Request.

Specifically, the control unit 90 obtains a change amount dPH of the hydrogen gas partial pressure PH ₂ were measured over a hydrogen gas partial pressure PH ₂ in a predetermined time period, the cross leakage amount Qc from variation dPH (= dPH × Calculate V / 101.3 × 273.15 / (273.15 + Tfc)).

  Here, V is the total volume of a closed circuit for circulating hydrogen gas between the anode gas flow passage 12a and the circulation pump 82, and Tfc is the anode exhaust gas discharged from the exhaust gas outlet 10c of the fuel cell 10. Temperature. Tfc is the temperature detected by the temperature sensor 91 b or the coolant temperature detected by the temperature sensor 11 a.

  Next, in step S170, the control unit 90 controls the injection 80 to open the hydrogen flow path between the hydrogen outlet of the hydrogen tank 70 and the hydrogen inlet of the fuel cell 10 over a predetermined period Ta.

  Here, the predetermined period Ta is the time required to supply the hydrogen gas of the cross leak amount Qc to the anode gas flow passage 12a of each cell 10a. For this reason, the hydrogen gas of the cross leak amount Qc can be supplied to the anode gas flow path 12a of each cell 10a. Then, it returns to step S110.

The control unit 90 determines at step S150, the when hydrogen gas partial pressure PH ₂ is less than the lower limit target value PL is the NO.

  In this case, in step S180, the control unit 90 controls the injection 80 to open a hydrogen flow path between the hydrogen outlet of the hydrogen tank 70 and the hydrogen inlet of the fuel cell 10 over a predetermined period Tb.

Here, the predetermined period Tb is a time required to supply a predetermined amount Q2 of hydrogen gas to the anode gas flow passage 12a of each cell 10a. Therefore, a predetermined amount Q2 of hydrogen gas can be supplied to the anode gas channel 12a for each cell 10a. The predetermined amount Q2, an anode when supplied to the gas passage 12a, the amount of hydrogen gas partial pressure of hydrogen gas PH ₂ is less than the threshold value Pth for each cell 10a of hydrogen gas at a predetermined amount Q2. Thereafter, the process returns to step S110.

  Steps S170 and S180 constitute a first hydrogen flow rate control unit.

According to the embodiment described above, the control unit 90, as in the first embodiment, when the power generation by the fuel cell 10 is not required, it determines that a hydrogen gas partial pressure PH ₂ is the threshold value Pth or more Then, the converter 40 is controlled so that surplus hydrogen gas is generated by the fuel cell 10 and the battery 50 is charged.

  Thereby, since the hydrogen gas partial pressure can be quickly reduced by power generation, it is possible to reduce the cross leak caused by the hydrogen gas pressure difference between the anode 12 and the cathode 13.

In the present embodiment, the control unit 90, when the hydrogen gas partial pressure PH ₂ is less than the lower limit target value PL controls the injection 80 supplies hydrogen gas at a predetermined amount Q2 to the anode gas passage 12a of each cell 10a To do. For this reason, it is possible to reduce the cross leak caused by the hydrogen gas pressure difference between the anode 12 and the cathode 13 while suppressing the deterioration of the fuel cell 10 (specifically, the anode 12) due to the lack of hydrogen gas.

Here, the predetermined amount Q2, as described above, when supplying the hydrogen gas of a predetermined amount Q2 to the anode gas passage 12a of each cell 10a, the amount of hydrogen gas partial pressure of hydrogen gas PH ₂ is less than the threshold value Pth It is. Therefore, even by supplying a hydrogen gas at a predetermined amount Q2 to the anode gas passage 12a of each cell 10a, the hydrogen gas partial pressure PH ₂ is less than the threshold value Pth, after the processing of step 180, step S130 (FC power generation・ Battery charging can be avoided.

In this embodiment, no more than a hydrogen gas partial pressure PH ₂ threshold Pth, and hydrogen when gas partial pressure PH ₂ is greater than the lower limit target value PL, the anode gas flow of each cell 10a of hydrogen gas cross leakage amount Qc Supply to path 12a. For this reason, the cross leak produced by the hydrogen gas pressure difference between the anode 12 and the cathode 13 can be reduced by suppressing the excessive rise in the hydrogen gas partial pressure.

  In the present embodiment, a hydrogen partial pressure detector 91 is provided near the anode gas outlet 10 c of the fuel cell 10. Here, the hydrogen gas concentration (that is, the hydrogen gas partial pressure) is lower in the vicinity of the anode gas outlet 10c of the fuel cell 10 than in the vicinity of the hydrogen gas inlet 10b of the fuel cell 10 and in the anode gas flow path 12a.

Therefore, of gas closed circuit gas is circulated between the anode gas passage 12a of the circulating pump 82 and each cell 10a, to detect hydrogen gas partial pressure PH ₂ in the most hydrogen gas concentration is low position it can.

Determines Whether such a hydrogen gas partial pressure PH ₂ with hydrogen gas partial pressure PH ₂ is greater than the lower limit target value PL in step S150. For this reason, the reliability of determination of step S150 can be improved.

Third Embodiment
In the first embodiment, an example in which the injection 80 is used to adjust the amount of hydrogen gas supplied from the hydrogen tank 70 to the fuel cell 10 has been described, but instead of this, the flow rate adjustment valve 80A is used. Three embodiments will be described with reference to FIG.

  The flow rate adjustment valve 80A includes a valve body for adjusting the opening area of the hydrogen gas flow path between the outlet of the hydrogen tank 70 and the hydrogen gas inlet of the fuel cell 10, and an electric actuator for driving this valve body.

  The flow rate adjustment valve 80A of the present embodiment is controlled by the control unit 90 to adjust the opening area of the hydrogen gas flow path. As a result, the flow rate of hydrogen gas flowing from the outlet of the hydrogen tank 70 to the hydrogen gas inlet of the fuel cell 10 can be adjusted.

  In the fuel cell system of the present embodiment, the configuration other than the flow rate adjustment valve 80A is the same as that of the fuel cell system of the first embodiment. For this reason, description of components other than the flow rate adjustment valve 80A in the fuel cell system is omitted.

Fourth Embodiment
In the fourth embodiment, a specific configuration of the hydrogen partial pressure detector 91 of the first embodiment will be described with reference to FIG.

  The hydrogen partial pressure detection unit 91 of the present embodiment is configured of a humidity sensor 91a, a temperature sensor 91b, and a pressure sensor 91c.

  The humidity sensor 91 a is a sensor that determines the humidity of the anode exhaust gas flowing from the anode gas outlet 10 c of the fuel cell 10. The temperature sensor 91b is a sensor for obtaining the temperature of the anode exhaust gas flowing from the anode gas outlet 10c of the fuel cell 10. The pressure sensor 91 c is a sensor for obtaining the total pressure of the anode exhaust gas flowing from the anode gas outlet 10 c of the fuel cell 10.

The control unit 90 obtains the partial pressure of water vapor based on the detection value of the humidity sensor 91a and the detection value of the temperature sensor 91b, and subtracts the water vapor partial pressure and the nitrogen gas partial pressure from the anode exhaust gas total pressure to obtain the hydrogen gas partial pressure. .

  Here, the nitrogen gas contained in the anode exhaust gas is a nitrogen gas which has moved from the cathode gas flow channel 13a to the anode gas flow channel 12a.

Here, the concentration of nitrogen gas contained in the anode exhaust gas is estimated by the nitrogen permeation amount NT due to the nitrogen partial pressure difference between the cathode and the anode, and the nitrogen discharge amount NH discharged from the exhaust water discharge valve 83 to the atmosphere. That is, the nitrogen gas partial pressure in the anode exhaust gas is estimated by the nitrogen permeation amount NT transmitted from the cathode to the anode and the nitrogen exhaust amount NH released to the atmosphere from the exhaust drainage valve.

  The nitrogen permeation amount NT changes with the temperature of the fuel cell 10 (specifically, the electrolyte membrane 11 of the cell 10a). For this reason, the nitrogen permeation amount NT is estimated by the temperature detected by the temperature sensor 11a. The nitrogen discharge amount NH is estimated by the valve opening time when the exhaust drainage valve 83 opens the exhaust drainage pipe 62 and the pressure in the exhaust drainage pipe 62. In the present embodiment, as the pressure in the exhaust drainage pipe 62, the anode exhaust gas total pressure detected by the pressure sensor 91c is used.

  Thus, the nitrogen gas partial pressure in the anode exhaust gas is determined by the detection temperature of the temperature sensor 11a, the valve opening time of the exhaust drainage valve 83, and the detection pressure of the pressure sensor 91c.

  As described above, the hydrogen gas partial pressure can be obtained from the detection value of the humidity sensor 91a, the detection value of the temperature sensor 91b, and the detection value of the pressure sensor 91c.

Fifth Embodiment
In the fourth embodiment, the example in which the hydrogen partial pressure detection unit 91 is configured by the humidity sensor 91a, the temperature sensor 91b, and the pressure sensor 91c has been described. Instead, the humidity sensor 91a, the temperature sensor 91b, and the gas A fifth embodiment in which the hydrogen partial pressure detection unit 91 is configured by the flow path sensor 91d will be described with reference to FIG.

  In the present embodiment, the gas flow path sensor 91d obtains the flow rate of the anode exhaust gas flowing from the anode gas outlet 10c of the fuel cell 10, and is used instead of the pressure sensor 91c. That is, the detection value of the gas flow path sensor 91 d is used to estimate the anode exhaust gas total pressure flowing from the anode gas outlet 10 c of the fuel cell 10.

  Here, the control unit 90 obtains the partial pressure of water vapor using the detection value of the humidity sensor 91a and the detection value of the temperature sensor 91b, as in the fourth embodiment.

  As described above, the hydrogen gas partial pressure can be obtained from the detection value of the humidity sensor 91a, the detection value of the temperature sensor 91b, and the detection value of the pressure sensor 91c.

(Other embodiments)
(1) In the first to fourth embodiments, the example in which the hydrogen partial pressure detection unit 91 is provided in the vicinity of the anode gas outlet 10c of the fuel cell 10 has been described. The hydrogen partial pressure detection unit 91 may be provided, or the hydrogen partial pressure detection unit 91 may be provided near the hydrogen gas inlet 10 b of the fuel cell 10.

(2) In the first to fourth embodiments have been described as being carried out determination of the step S120, S150 with hydrogen gas partial pressure PH ₂ of the detection value of the hydrogen partial pressure detecting unit, instead of this May be as follows.

That is, the control unit 90 estimates the total pressure of the anode exhaust gas flowing in the anode gas flow path 12a for each cell 10a as an estimated value of the hydrogen gas partial pressure. Controller 90 replaces the hydrogen gas partial pressure PH _2, to implement the determination of step S120, S150 using the total pressure of the anode exhaust gas to be the estimation.

  (3) In the first to fourth embodiments, the example in which the fuel cell system of the present invention is applied to an automobile has been described. Instead, the fuel cell system of the present invention is used for an installed generator. Also good.

  (4) In addition, this invention is not limited to above-described embodiment, In the range described in the claim, it can change suitably. Moreover, said each embodiment is not mutually irrelevant and can be combined suitably, unless the combination is clearly impossible. Further, in each of the above-described embodiments, it is needless to say that the elements constituting the embodiment are not necessarily essential except when clearly indicated as being essential and when it is considered to be obviously essential in principle. Yes. Further, in the above embodiments, when numerical values such as the number, numerical value, amount, range, etc. of constituent elements of the embodiment are mentioned, it is clearly indicated that they are particularly essential and clearly limited to a specific number in principle. The number is not limited to the specific number except for the case. Further, in the above embodiments, when referring to the shape, positional relationship, etc. of the component etc., unless otherwise specified or in principle when limited to a specific shape, positional relationship, etc., the shape, etc. It is not limited to the positional relationship and the like.

(Summary)
According to the first aspect described in the first to third embodiments and part or all of the other embodiments, in the fuel cell system, a fuel cell having a single cell including a fuel electrode and an oxygen electrode. A hydrogen supply unit for supplying hydrogen gas to the fuel electrode, and an exhaust gas containing hydrogen gas discharged from the fuel electrode without being used for power generation of the fuel cell mixed with the hydrogen gas from the hydrogen supply unit to the fuel electrode A first power output that outputs to the electric load the power generated by the fuel cell using a circulation pump that supplies and circulates the exhaust gas, an oxidant supply unit that supplies an oxidant to the oxygen electrode, and hydrogen gas and an oxidant. And a second power output unit for charging the battery with the electric power generated by the fuel cell using hydrogen gas and an oxidant, and, when power generation by the fuel cell is required, the fuel cell is used to generate electric power Load electric power The first power generation control unit that controls the first power output unit to output, the hydrogen partial pressure detection unit that detects the hydrogen gas partial pressure in the fuel electrode, and the detection value of the hydrogen partial pressure detection unit are higher than the threshold The first hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is higher than the threshold when the first hydrogen partial pressure determination unit determines whether the fuel cell is not required and the fuel cell does not require power generation. And a second power generation control unit configured to control the second power output unit to generate power by the fuel cell and to charge the battery with the generated power.

  According to the second aspect, the power corresponding to the difference between the target lower limit value lower than the threshold value and the detection value of the hydrogen partial pressure detection unit is set as the upper limit power, and the second power generation control unit is configured to generate power generated by the fuel cell. The second power output unit is controlled to be equal to or less than the upper limit power.

  As a result, it can be suppressed that the hydrogen gas partial pressure in the fuel electrode becomes lower than the target lower limit value, so deterioration of the fuel cell can be suppressed due to the lack of hydrogen gas.

  According to the third aspect, the second hydrogen partial pressure determination unit that determines whether or not the detection value of the hydrogen partial pressure detection unit is higher than the target lower limit value, and when the power generation by the fuel cell is not required, The first hydrogen partial pressure determination unit determines that the detection value of the pressure detection unit is less than the threshold value, and the second hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is higher than the target lower limit value. In this case, the amount of change in the detection value of the hydrogen partial pressure detection unit is obtained, the amount of hydrogen gas passing from the fuel electrode to the oxygen electrode is calculated based on the obtained amount of change, and hydrogen equivalent to the calculated amount of hydrogen gas is calculated. And a first hydrogen flow control unit that controls the hydrogen supply unit to supply a gas amount to the fuel electrode.

  Thereby, generation | occurrence | production of the cross leak from an oxygen electrode to a fuel electrode can be suppressed.

  According to the fourth aspect, when power generation by the fuel cell is not required, when the second hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is equal to or lower than the target lower limit value, A second hydrogen flow rate control unit that controls the hydrogen supply unit so that a predetermined amount of hydrogen gas is supplied to the fuel electrode, and the predetermined amount is obtained when a predetermined amount of hydrogen gas is supplied from the hydrogen tank to the fuel electrode. This is the amount of hydrogen gas at which the hydrogen gas partial pressure at the fuel electrode falls below the threshold.

  Therefore, even if the hydrogen gas from the hydrogen tank is supplied to the fuel electrode, it is possible to prevent the second power generation control unit from performing power generation in advance.

  According to the fifth aspect, the threshold value and the target lower limit value are set to be larger than the reference value of the hydrogen gas partial pressure that causes deterioration of the fuel cell due to the lack of hydrogen gas.

  According to the sixth aspect, the first power generation control unit controls the first power output unit and the second power output unit so that the power from the battery is given priority over the power from the fuel cell and is output to the electric load. Do.

  As a result, even when large power generation by the fuel cell is required, power from the battery is given priority over the power from the fuel cell and output to the electric load, so a large amount of hydrogen gas is consumed in a short period of time. In addition to suppressing the occurrence of hydrogen gas deficiency, it is possible to balance the charge and discharge of the battery so that the control of the present fuel cell system is established.

  According to the seventh aspect, the hydrogen partial pressure detector obtains, as a detected value, an estimated value obtained by estimating the partial pressure of hydrogen gas based on a detected value of a pressure sensor that detects the total pressure of the gas in the fuel electrode.

DESCRIPTION OF SYMBOLS 10 Fuel cell 10a Cell 11 Cathode 12 Anode 80 Injector 82 Circulation pump 20 Electric load 30 Inverter 40 Converter 50 Battery 90 Control part

Claims (7)

A fuel cell (10) having a single cell (10a) comprising a fuel electrode (12) and an oxygen electrode (11);
A hydrogen supply unit (80, 80A) for supplying hydrogen gas to the fuel electrode;
A circulation pump which mixes exhaust gas containing hydrogen gas discharged from the fuel electrode without being used for power generation of the fuel cell with hydrogen gas from the hydrogen supply unit and supplies it to the fuel electrode to circulate the exhaust gas ( 82)
An oxidant supply unit (84) for supplying an oxidant to the oxygen electrode;
A first power output unit (30) that outputs the power generated by the fuel cell using the hydrogen gas and the oxidant to an electric load (20);
A second power output unit (40) for charging the battery (50) with electric power generated by the fuel cell using the hydrogen gas and the oxidant;
When the power generation by the fuel cell is required, the first power generation control unit (S140) controls the first power output unit to cause the fuel cell to generate power and output the generated power to the electric load (S140) )When,
A hydrogen partial pressure detection unit (91) for detecting a hydrogen gas partial pressure in the fuel electrode;
A first hydrogen partial pressure determination unit (S120) for determining whether or not a detection value of the hydrogen partial pressure detection unit is higher than a threshold value (Pth);
When the first hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is higher than the threshold value when power generation by the fuel cell is not required, the fuel cell is caused to generate electric power A second power generation control unit (S130) for controlling the second power output unit to charge the battery with the generated power,
A fuel cell system comprising: The power corresponding to the difference (ΔP) between the target lower limit (PL) lower than the threshold and the detection value of the hydrogen partial pressure detection unit is defined as the upper limit power.
2. The fuel cell system according to claim 1, wherein the second power generation control unit controls the second power output unit so that power generated by the fuel cell is equal to or lower than the upper limit power. A second hydrogen partial pressure determination unit (S150) for determining whether or not the detection value of the hydrogen partial pressure detection unit is higher than the target lower limit value;
When power generation by the fuel cell is not required, the first hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is less than a threshold, and the hydrogen partial pressure detection is more than the target lower limit value. When the second hydrogen partial pressure determination unit determines that the detected value of the unit is high, the amount of change in the detected value of the hydrogen partial pressure detection unit is determined, and the determined amount of change determines the oxygen from the fuel electrode The first hydrogen flow control unit (S170, S160) which calculates the amount of hydrogen gas passing to the pole and controls the hydrogen supply unit to supply the amount of hydrogen gas equivalent to the calculated amount of hydrogen gas to the fuel electrode When,
The fuel cell system according to claim 2, comprising: When the second hydrogen partial pressure determination unit determines that the detection value of the hydrogen partial pressure detection unit is less than or equal to a target lower limit when power generation by the fuel cell is not required, a predetermined amount of hydrogen from the hydrogen tank is determined. A second hydrogen flow rate control unit (S180) for controlling the hydrogen supply unit to supply hydrogen gas to the fuel electrode;
4. The apparatus according to claim 3, wherein the predetermined amount is an amount of the hydrogen gas at which a partial pressure of hydrogen gas of the fuel electrode is equal to or less than the threshold value when hydrogen gas of a predetermined amount is supplied to the fuel electrode from the hydrogen tank. Fuel cell system.   The threshold value and the target lower limit value are set to be larger than a reference value (Pd) of the hydrogen gas partial pressure at which the fuel cell is deteriorated due to the lack of the hydrogen gas. 5. The fuel cell system according to any one of 4.   The first power generation control unit controls the first power output unit and the second power output unit so that power from the battery is output to the electric load with priority over power from the fuel cell. Item 6. The fuel cell system according to any one of Items 1 to 5.   7. The hydrogen partial pressure detection unit obtains an estimated value obtained by estimating a partial pressure of the hydrogen gas based on a detection value of a pressure sensor that detects a total pressure of gas in the fuel electrode as the detection value. The fuel cell system according to any one of the above.

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