JP2011216415A - Fuel cell system and film wet condition determination method for the same - Google Patents

Abstract

A method of determining a membrane wet state of a fuel cell in real time.
A humidifier inlet air humidity is obtained based on an atmospheric pressure, an intake air temperature of an air pump 2, and an inlet air temperature of a humidifier 4, and a cathode outlet air temperature of the fuel cell stack 1 and a refrigerant of the fuel cell stack 1 are obtained. The cathode outlet air humidity is obtained based on the refrigerant temperature at the outlet, and the temporary humidity of the cathode of the fuel cell stack 1 is obtained by referring to the map based on the humidifier inlet air humidity and the cathode outlet air humidity. The water level of the cathode side catch tank 26 provided is detected by a water level sensor 27, and the correction coefficient is based on the difference in water level between the detected actual water level and the reference water level in the cathode side catch tank 26 in the steady operation state of the fuel cell stack 1. The cathode humidity is obtained by multiplying the provisional cathode humidity by the correction coefficient.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell system and a method for determining a membrane wet state of a fuel cell in the fuel cell system.

  In a fuel cell system equipped with a solid polymer electrolyte membrane type fuel cell, humidity control inside the fuel cell is extremely important because the humidified state inside the fuel cell greatly affects the power generation performance of the fuel cell.

  As a conventional method for determining the humidity, for example, when the cell voltage of the fuel cell is decreased, the flow rate of the oxidant gas is increased, and then the voltage difference between the average cell voltage and the minimum cell voltage is detected. A method is known in which it is determined that humidification is insufficient when the value is equal to or less than the determination value, and overhumidation is determined when it is greater than the determination value (see, for example, Patent Document 1).

  As another humidity determination method, there is also known a method of detecting a cell whose cell voltage is below the normal range and determining the humidified state of the fuel cell stack based on the stacking position of the abnormal cell in the fuel cell stack ( For example, see Patent Document 2).

JP 2007-194177 A JP 2002-184438 A

Any of the conventional humidity determination methods can only perform qualitative determination as to whether the humidity state inside the fuel cell is normal, insufficient humidity, or excessive humidification.
However, in order to always keep the fuel cell system in an optimal operating state, it is required to grasp the humidity inside the fuel cell quantitatively and in real time, and the conventional humidity determination method can meet this requirement. There wasn't.

  Accordingly, the present invention provides a fuel cell system that can quantitatively and in real time understand the membrane wet state of a fuel cell, and a method for determining the membrane wet state of a fuel cell system.

The present invention employs the following means in order to solve the above problems.
The invention according to claim 1 includes a fuel cell (for example, a fuel cell stack 1 in an embodiment to be described later) having an anode and a cathode sandwiching a solid polymer electrolyte membrane, and generating power by being supplied with a reaction gas;
A cathode discharge passage (for example, an air offgas passage 5 in an embodiment described later) through which a cathode offgas discharged from the cathode of the fuel cell (for example, an air offgas in an embodiment described later) flows;
A cathode discharge water storage section (for example, a cathode side catch tank 26 in an embodiment to be described later), which is provided in the cathode discharge flow path and temporarily stores condensed water of moisture contained in the cathode off gas;
Water level measuring means for measuring the water level of the cathode discharge water storage section (for example, a water level sensor 27 in an embodiment described later);
Environmental condition measuring means for measuring environmental conditions of the fuel cell (for example, an atmospheric pressure sensor 30 and an intake air temperature sensor 31 in an embodiment described later);
Fuel cell temperature condition measuring means for measuring the temperature condition of the fuel cell (for example, a humidifier inlet temperature sensor 32, a cathode outlet temperature sensor 33, a refrigerant outlet temperature sensor 34 in an embodiment described later);
Cathode humidity calculating means for calculating the humidity of the cathode based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means (for example, implementation described later) An electronic control device 50) in the example,
The cathode humidity calculation means includes
A determination value calculation unit (for example, implementation described later) that calculates two determination values based on the environmental condition value measured by the environmental condition measurement unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measurement unit Steps S01 and S02) in the example,
A provisional cathode humidity calculation unit (for example, step S03 in an embodiment described later) for obtaining provisional humidity of the cathode from the two determination values;
Correction coefficient calculation for obtaining a correction coefficient based on a comparison value between the actual water level of the cathode discharge water storage unit measured by the water level measuring means and the reference water level of the cathode discharge water storage unit in the steady operation state of the fuel cell And
A cathode humidity correction unit for determining the humidity of the cathode by multiplying the temporary cathode humidity determined by the temporary cathode humidity calculation unit by the correction coefficient determined by the correction coefficient calculation unit (for example, step S06 in the embodiment described later) S07, S08),
A fuel cell system comprising:

The invention according to claim 2 includes a fuel cell (for example, a fuel cell stack 1 in an embodiment to be described later) having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas;
An anode discharge passage (for example, a hydrogen offgas recovery passage 12 in an embodiment described later) through which an anode offgas discharged from the anode of the fuel cell (for example, a hydrogen offgas in an embodiment described later) flows;
An anode discharge water storage section (for example, an anode side catch tank 13 in an embodiment to be described later) provided in the anode discharge flow path for temporarily storing condensed water of moisture contained in the anode off gas;
Water level measuring means (for example, a water level sensor 41 in an embodiment described later) for measuring the water level of the anode drainage water storage unit;
Environmental condition measuring means for measuring environmental conditions of the fuel cell (for example, an atmospheric pressure sensor 30 and an intake air temperature sensor 31 in an embodiment described later);
Fuel cell temperature condition measuring means for measuring the temperature condition of the fuel cell (for example, a humidifier inlet temperature sensor 32, a cathode outlet temperature sensor 33, a refrigerant outlet temperature sensor 34 in an embodiment described later);
Anode humidity calculating means for calculating the humidity of the anode based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means (for example, implementation described later) An electronic control device 50) in the example,
The anode humidity calculating means includes
A determination value calculation unit (for example, implementation described later) that calculates two determination values based on the environmental condition value measured by the environmental condition measurement unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measurement unit Steps S101, S102) in the example;
A temporary anode humidity calculator (for example, step S103 in the embodiment described later) for obtaining the temporary humidity of the anode from the two determination values;
Correction coefficient calculation for obtaining a correction coefficient based on a comparison value between the actual water level of the anode discharge water storage unit measured by the water level measurement means and the reference water level of the anode discharge water storage unit in a steady operation state of the fuel cell And
An anode humidity correction unit that calculates the humidity of the anode by multiplying the temporary anode humidity calculated by the temporary anode humidity calculation unit by the correction coefficient calculated by the correction coefficient calculation unit (for example, step S106 in the embodiments described later, S107, S108),
A fuel cell system comprising:

The invention according to claim 3 includes a fuel cell (for example, a fuel cell stack 1 in an embodiment to be described later) having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas;
An anode reaction gas circulation passage (for example, a hydrogen supply passage 8 and a hydrogen off-gas recovery passage 12 in the embodiments described later) for returning the anode off-gas discharged from the anode of the fuel cell back to the anode of the fuel cell;
A fuel pump (for example, a hydrogen pump 42 in an embodiment described later) provided in the anode reaction gas circulation flow path;
A water level measuring means (for example, a water level sensor 43 in an embodiment described later) for measuring the water level of a reservoir in which condensed water of moisture contained in the anode off gas temporarily accumulates in the fuel pump;
Environmental condition measuring means for measuring environmental conditions of the fuel cell (for example, an atmospheric pressure sensor 30 and an intake air temperature sensor 31 in an embodiment described later);
Fuel cell temperature condition measuring means for measuring the temperature condition of the fuel cell (for example, a humidifier inlet temperature sensor 32, a cathode outlet temperature sensor 33, a refrigerant outlet temperature sensor 34 in an embodiment described later);
Anode humidity calculating means for calculating the humidity of the anode based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means (for example, implementation described later) An electronic control device 50) in the example,
The anode humidity calculating means includes
A determination value calculation unit (for example, implementation described later) that calculates two determination values based on the environmental condition value measured by the environmental condition measurement unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measurement unit Steps S101, S102) in the example;
A temporary anode humidity calculator (for example, step S103 in the embodiment described later) for obtaining the temporary humidity of the anode from the two determination values;
A correction coefficient calculation unit for obtaining a correction coefficient based on a comparison value between the actual water level of the storage unit measured by the water level measuring unit and the reference water level of the storage unit in a steady operation state of the fuel cell;
An anode humidity correction unit that calculates the humidity of the anode by multiplying the temporary anode humidity calculated by the temporary anode humidity calculation unit by the correction coefficient calculated by the correction coefficient calculation unit (for example, step S106 in the embodiments described later, S107, S108),
A fuel cell system comprising:

According to a fourth aspect of the present invention, there is provided a fuel cell (for example, a fuel cell stack 1 in an embodiment to be described later) having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating a power by being supplied with a reaction gas; Environmental condition measuring means for measuring the environmental conditions of the fuel cell (for example, an atmospheric pressure sensor 30 and an intake air temperature sensor 31 in the embodiments described later) and fuel cell temperature condition measuring means for measuring the temperature conditions of the fuel cell (for example, In a method for determining a wet state of the solid polymer electrolyte membrane in a fuel cell system comprising a humidifier inlet temperature sensor 32, a cathode outlet temperature sensor 33, and a refrigerant outlet temperature sensor 34) in an embodiment described later.
A judgment value calculation step for obtaining two judgment values based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means (for example, an embodiment described later) Steps S01, S02) in FIG.
A provisional cathode humidity calculation step (for example, step S03 in the embodiment described later) for obtaining provisional humidity of the cathode based on the two determination values using a map created in advance;
Based on a comparison value between the actual amount of condensed water contained in the cathode offgas discharged from the cathode of the fuel cell and the reference amount of condensed water contained in the cathode offgas in the steady operation state of the fuel cell. A correction coefficient calculation step for obtaining a correction coefficient by
A cathode humidity correction step for obtaining the cathode humidity by multiplying the provisional humidity of the cathode by the correction coefficient (for example, steps S06, S07, S08 in the embodiments described later);
The wet state of the solid polymer electrolyte membrane is determined in order, and the wet state of the membrane of the fuel cell system is determined.

According to a fifth aspect of the present invention, there is provided a fuel cell (for example, a fuel cell stack 1 in an embodiment to be described later) having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating a power by being supplied with a reaction gas; Environmental condition measuring means for measuring the environmental conditions of the fuel cell (for example, an atmospheric pressure sensor 30 and an intake air temperature sensor 31 in the embodiments described later) and fuel cell temperature condition measuring means for measuring the temperature conditions of the fuel cell (for example, In a method for determining a wet state of the solid polymer electrolyte membrane in a fuel cell system comprising a humidifier inlet temperature sensor 32, a cathode outlet temperature sensor 33, and a refrigerant outlet temperature sensor 34) in an embodiment described later.
A judgment value calculation step for obtaining two judgment values based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means (for example, an embodiment described later) Steps S101 and S102),
A temporary anode humidity calculation step (for example, step S103 in the embodiment described later) for obtaining a temporary humidity of the anode based on the two determination values using a map created in advance;
Based on a comparison value between the actual amount of condensed water of moisture contained in the anode off gas discharged from the anode of the fuel cell and the reference amount of condensed water of moisture contained in the anode off gas in the steady operation state of the fuel cell. A correction coefficient calculation step for obtaining a correction coefficient by
An anode humidity correction step (for example, steps S106, S107, and S108 in the embodiments described later) for determining the humidity of the anode by multiplying the provisional humidity of the anode by the correction coefficient;
The wet state of the solid polymer electrolyte membrane is determined in order, and the wet state of the membrane of the fuel cell system is determined.

According to the first aspect of the present invention, the humidity of the cathode of the fuel cell stack can be estimated in real time with a value very close to the true value.
According to the invention of claim 2, the humidity of the anode of the fuel cell stack can be estimated in real time with a value very close to the true value.
According to the invention of claim 3, the humidity of the anode of the fuel cell stack can be estimated in real time with a value very close to the true value.
According to the invention of claim 4, the wet state of the solid polymer electrolyte membrane of the fuel cell stack can be grasped very accurately based on the estimated value of the humidity of the cathode.
According to the fifth aspect of the present invention, the wet state of the solid polymer electrolyte membrane of the fuel cell stack can be grasped very accurately based on the estimated value of the humidity of the anode.

It is a schematic block diagram in Example 1 of the fuel cell system concerning this invention. 3 is a flowchart illustrating a humidity determination process for a cathode in the first embodiment. It is a humidifier entrance air humidity map used in Example 1. FIG. 2 is a cathode outlet air humidity map used in Example 1. FIG. 2 is a cathode humidity map used in Example 1. FIG. It is a time chart of the water level of a cathode side catch tank. 3 is a correction coefficient map using as a parameter the water level difference of the cathode side catch tank used in the first embodiment. It is a schematic block diagram in Example 2 of the fuel cell system concerning this invention. 10 is a flowchart illustrating anode humidity determination processing according to the second embodiment. It is an anode humidity map used in Example 2. It is a principal part block diagram in Example 3 of the fuel cell system concerning this invention.

  Embodiments of a fuel cell system according to the present invention and a method for determining a membrane wet state of the fuel cell system will be described below with reference to the drawings of FIGS. In addition, each Example demonstrated below is the aspect applied to the fuel cell system mounted in a fuel cell vehicle.

<Example 1>
First, Embodiment 1 of a fuel cell system and a film wet state determination method for a fuel cell system according to the present invention will be described with reference to the drawings of FIGS.
FIG. 1 is a schematic configuration diagram of a fuel cell system according to a first embodiment. A fuel cell stack (fuel cell) 1 includes a plurality of unit fuel cells (hereinafter referred to as single cells) formed by sandwiching a solid polymer electrolyte membrane made of, for example, a solid polymer ion exchange membrane between an anode and a cathode from both sides. A hydrogen electrode supplied with hydrogen gas as a fuel gas, an air electrode supplied with air containing oxygen as an oxidant gas, and a cooling passage supplied with a coolant. Then, hydrogen ions generated by the catalytic reaction at the anode move through the solid polymer electrolyte membrane to the cathode, cause an electrochemical reaction with oxygen at the cathode, and generate electric power, thereby generating water. In order to prevent the fuel cell stack 1 from exceeding the upper limit temperature due to heat generated by the power generation, the cooling liquid flowing through the cooling passage removes heat and cools it.

  The outside air is pressurized by an air pump (compressor) 2, supplied to the air electrode of the fuel cell stack 1 through the supply air passage 3 and the humidifier 4, and oxygen in the air is supplied to the power generation as an oxidant. The fuel cell stack 1 is discharged as air off-gas (cathode off-gas), passes through an air off-gas passage (cathode discharge passage) 5 and the humidifier 4 and is discharged to a dilution box (diluter) 6. In the following description, the air supplied to the fuel cell stack 1 is referred to as supply air in order to distinguish it from the air off-gas discharged from the fuel cell stack 1.

In the air off-gas passage 5 upstream of the humidifier 4, a cathode-side catch tank 26 that temporarily stores condensed water of moisture contained in the air off-gas discharged from the cathode of the fuel cell stack 1 is provided.
The cathode catch tank 26 is provided with a water level sensor 27 for measuring the water level of the stored water. Further, the cathode side catch tank 26 is connected to the dilution box 6 via a drain passage 29 provided with a drain valve 28, and the drain valve 28 is controlled to be opened every predetermined time and collected in the cathode side catch tank 26. Drain the collected water into the dilution box 6.

The humidifier 4 is configured to include a water permeable membrane such as a hollow fiber membrane, for example, and the air off-gas discharged from the fuel cell stack 1 is used as a reaction gas to humidify the supplied air supplied to the fuel cell stack 1. It is used as. In the humidifier 4, the supply air is humidified by contact between the supply air and the air off gas through the water permeable membrane, and moisture contained in the air off gas passes through the membrane holes of the water permeable membrane and moves to the supply air. The By supplying the air thus humidified to the fuel cell stack 1, the ionic conductivity of the solid polymer electrolyte membrane of the fuel cell stack 1 is ensured in a predetermined state.
The rotation speed of the air pump 2 is controlled so that air having a mass corresponding to the output required for the fuel cell stack 1 is supplied to the air electrode.

  On the other hand, the hydrogen gas released from the hydrogen tank 7 is supplied to the hydrogen electrode of the fuel cell stack 1 through the hydrogen supply passage 8, the hydrogen cutoff valve 9, the pressure control valve 10, and the ejector 11. After this hydrogen gas is used for power generation, the unreacted hydrogen gas is discharged from the fuel cell stack 1 as hydrogen offgas (anode offgas) and sucked into the ejector 11 through the hydrogen offgas recovery path (anode discharge path) 12. Then, it merges with the hydrogen gas supplied from the hydrogen tank 7 and is supplied to the fuel cell stack 1 again.

  The pressure control valve 10 is composed of, for example, a pneumatic proportional pressure control valve. The pressure control valve 10 is input via the air signal introduction path 19 using the pressure of the supply air supplied from the air pump 2 as a signal pressure, and the outlet of the pressure control valve 10. The pressure of the hydrogen gas is controlled to be reduced so that the hydrogen gas pressure on the side falls within a predetermined pressure range corresponding to the signal pressure. Thus, by controlling the pressure of the hydrogen gas supplied to the fuel cell stack 1 by the pressure control valve 10 using the pressure of the supply air as a reference pressure, the flow rate of the hydrogen gas passing through the ejector 11 is controlled, The differential pressure between the air pressure and the hydrogen gas pressure through the solid polymer electrolyte membrane in the fuel cell stack 1 is controlled to be within a predetermined range.

The hydrogen off-gas recovery path 12 branches from a hydrogen off-gas purge path 15 having a purge valve 14 and is connected to the dilution box 6. The purge valve 14 is normally closed and is controlled to open according to the operating state of the fuel cell stack 1, and discharges the hydrogen off-gas flowing through the hydrogen off-gas recovery path 12 to the dilution box 6.
The hydrogen off-gas discharged to the dilution box 6 is diluted by the air off-gas discharged to the dilution box 6 and is released to the outside air through the exhaust passage 18. A hydrogen sensor 40 is provided at the outlet of the dilution box 6 for detecting the hydrogen concentration of the gas released into the outside air.

  Further, the coolant for cooling the fuel cell stack 1 is pressurized by the water pump 20 and supplied to the fuel cell stack 1, and takes heat from the fuel cell stack 1 when passing through the cooling passage in the fuel cell stack 1. Then, the fuel cell stack 1 is cooled, and the heated coolant is sent to a radiator (radiator) 21, and the radiator 21 radiates heat to the outside to cool the coolant, and returns to the water pump 20 again. It has become. A bypass passage 23 that bypasses the radiator 21 is connected to the coolant circulation circuit 22, and the coolant is passed through the bypass passage 23 by a thermostat valve 24 provided at a connection portion between the circulation circuit 22 and the bypass passage 23. It is determined whether to circulate through the radiator 21 without passing through or to circulate through the bypass passage 23 without passing through the radiator 21. That is, when the coolant is lower than the predetermined temperature, it is not necessary to cool the coolant. Therefore, the coolant is circulated between the fuel cell stack 1 via the bypass passage 23 without passing through the radiator 21, and the coolant is When the temperature is higher than the predetermined temperature, it is necessary to cool the coolant. Therefore, the coolant is circulated between the fuel cell stack 1 and the radiator 21 without passing through the bypass passage 23. In the figure, reference numeral 25 denotes a reserve tank, which is connected to the radiator 21 and the water pump 20.

  The fuel cell system is provided with various sensors for detecting a physical quantity necessary for estimating the humidity of the cathode or anode in the fuel cell stack 1. That is, the fuel cell system includes an atmospheric pressure sensor 30 that detects the atmospheric pressure P, an intake air temperature sensor 31 that detects the temperature of air sucked into the air pump 2 (hereinafter referred to as an air pump intake temperature) T1, and a humidifier 4. A humidifier inlet temperature sensor 32 for detecting the temperature of the supplied air (hereinafter referred to as humidifier inlet air temperature) T2, and the temperature of the air off-gas before being supplied to the humidifier 4 after being discharged from the fuel cell stack 1 (hereinafter referred to as humidifier inlet temperature sensor 32). A cathode outlet temperature sensor 33 for detecting T3 (referred to as cathode outlet air temperature), and a refrigerant outlet temperature sensor 34 for detecting a temperature T4 of the coolant immediately after being discharged from the fuel cell stack 1 (hereinafter referred to as refrigerant outlet temperature). The output signals of these sensors 30 to 34 are input to an electronic control unit (ECU) 50.

  In this embodiment, the atmospheric pressure sensor 30 and the intake air temperature sensor 31 constitute an environmental condition measuring means, and the humidifier inlet temperature sensor 32, the cathode outlet temperature sensor 33, and the refrigerant outlet temperature sensor 34 measure the fuel cell stack temperature condition. The electronic control unit 50 constitutes a cathode humidity calculation means.

Next, a method of estimating the humidity of the cathode or the humidity of the anode in the fuel cell stack 1 in this fuel cell system will be described.
The inventor of the present application has supplied the atmospheric pressure P, the air pump intake air temperature T1, the humidifier inlet air temperature T2, and the humidifier 4 through many experiments conducted on the fuel cell system configured as described above. That there is a correlation with the humidity of the air (hereinafter referred to as humidifier inlet air humidity) A, cathode outlet air temperature T3, refrigerant outlet temperature T4, and air discharged from the cathode of the fuel cell stack 1 And the humidity at the cathode in the fuel cell stack 1 (hereinafter referred to as “humidifier inlet air humidity A”, cathode outlet air humidity “B”) It was empirically found that there is a correlation between Hc (referred to as cathode humidity) and humidity at the anode (hereinafter referred to as anode humidity) Ha.

  Note that there is a correlation among the humidifier inlet air humidity A, the cathode outlet air humidity B, and the anode humidity Ha in the fuel cell stack 1 in this fuel cell system as described above. By controlling the pressure control valve 10 using the pressure of the supply air as a reference pressure, the pressure of the hydrogen gas supplied to the fuel cell stack 1 is controlled, and the flow rate of the hydrogen gas passing through the ejector 11 is controlled. .

  Therefore, in the present invention, the environmental conditions around the fuel cell stack 1 and the operating conditions of the fuel cell stack 1 are variously changed in advance with respect to the fuel cell system as a standard model actually assembled for a fuel cell vehicle. Then, a large number of data of each physical quantity having the correlation is collected, and based on this, maps as shown in FIGS. 3 to 5 and 10 are created in advance and stored in the storage means of the electronic control unit 50. Keep it. When collecting the data in advance, the standard fuel cell system is provided with sensors for detecting the humidifier inlet air humidity A, the cathode outlet air humidity B, the cathode humidity Hc, and the anode humidity Ha. .

  The humidifier inlet air humidity map shown in FIG. 3 is a map created based on data of the atmospheric pressure P, the air pump intake air temperature T1, the humidifier inlet air temperature T2, and the humidifier inlet air humidity A. For each magnitude (atmospheric pressure value) of the atmospheric pressure P, the humidifier inlet air humidity A can be retrieved from the air pump intake air temperature T1 and the humidifier inlet air temperature T2. That is, the map shown in FIG. 3 is a humidifier inlet air humidity map when the atmospheric pressure has a certain value, and many such maps are created for each atmospheric pressure value.

  The cathode outlet air humidity map shown in FIG. 4 is a map created based on the data of the cathode outlet air temperature T3, the refrigerant outlet temperature T4, and the cathode outlet air humidity B. The cathode outlet air temperature T3 and the refrigerant outlet The cathode outlet air humidity B can be searched from the temperature T4.

  The cathode humidity map shown in FIG. 5 is a map created based on the data of the humidifier inlet air humidity A, the cathode outlet air humidity B, and the cathode humidity Hc, and the humidifier inlet air humidity A and the cathode outlet air humidity B. Thus, the cathode humidity Hc can be retrieved.

  The anode humidity map shown in FIG. 10 is a map created based on the data of the humidifier inlet air humidity A, the cathode outlet air humidity B, and the anode humidity Ha, and the humidifier inlet air humidity A and the cathode outlet air humidity B. Thus, the anode humidity Ha can be retrieved.

  By using the humidifier inlet air humidity map of FIG. 3, the cathode outlet air humidity map of FIG. 4, and the cathode humidity map of FIG. 5, the atmospheric pressure P, the air pump intake air temperature T1, the humidifier inlet air temperature T2, and the cathode The cathode humidity Hc in the fuel cell stack 1 can be predicted based on the outlet air temperature T3 and the refrigerant outlet temperature T4.

  Further, by using the humidifier inlet air humidity map in FIG. 3, the cathode outlet air humidity map in FIG. 4, and the anode humidity map in FIG. 10, the atmospheric pressure P, the air pump intake air temperature T1, and the humidifier inlet air temperature T2 The anode humidity Ha in the fuel cell stack 1 can be predicted based on the cathode outlet air temperature T3 and the refrigerant outlet temperature T4.

  However, the cathode humidity Hc or anode humidity Ha predicted in this way is a predicted value when applied to a standard model fuel cell system, and the inside of the fuel cell stack 1 in the fuel cell system that is actually operating now. It is hard to say that the moisture status of the water is reflected.

  Therefore, in the present invention, the cathode humidity Hc or the anode humidity Ha predicted based on the map is used as the temporary cathode humidity or the temporary anode humidity, and the current operation is performed with respect to the temporary cathode humidity or the temporary anode humidity. In this fuel cell system, the correction according to the moisture state in the fuel cell stack 1 is performed, so that the cathode humidity Hc or the anode humidity Ha closer to the true value can be estimated in real time.

Next, a correction method for the temporary cathode humidity in the first embodiment will be described.
There is a correlation between the amount of condensed water per unit time of the air off gas and the cathode humidity of the fuel cell stack. The higher the cathode humidity, the larger the amount of condensed water per unit time of the air off gas. Therefore, in Example 1, the amount of dew condensation water of the air off gas at a predetermined time is measured, and this is compared with the amount of dew condensation water (reference dew condensation water amount) used as a reference when the cathode humidity is in a standard humidified state (for example, humidity 70%). The correction coefficient was obtained from the comparison value to correct the temporary cathode humidity.

Specifically, the dew condensation water of the air off gas is stored in the cathode side catch tank 26, and the drain valve 28 is opened and drained at a predetermined interval. Therefore, from the water level of the cathode side catch tank 26 before the drainage, a predetermined time is reached. The amount of condensed water of the air off gas during the interval can be determined.
FIG. 6 is a time chart showing temporal changes in the opening / closing timing of the drain valve 28 and the water level of the water stored in the cathode side catch tank 26.

  On the other hand, since the amount of condensed water per unit time of the air off gas when the fuel cell stack 1 is in the steady operation state and the cathode humidity is in the standard humidified state is experimentally known, the time of the interval is added to this known amount of condensed water. By multiplying, the reference dew condensation water amount can be obtained, and since the size of the cathode catch tank 26 is known in advance, the water level (reference water level) at that time can also be calculated.

  In the first embodiment, instead of comparing the amount of condensed water stored in the cathode-side catch tank 26, the water level of condensed water stored in the cathode-side catch tank 26 is compared. When the water level of 26 is larger than the reference water level, it is estimated that the cathode humidity is higher than the standard humidification state. In this case, the correction coefficient Y is set so as to increase, and the actual cathode side catch tank When the water level of 26 is smaller than the reference water level, it is estimated that the cathode humidity is lower than the standard humidification state. In this case, the correction coefficient Y is set so as to decrease.

In order to realize this, as described above, the water level sensor 27 is provided in the cathode side catch tank 26, and the output signal of the water level sensor 27 is output to the electronic control unit 50.
FIG. 7 is an example of a correction coefficient map that uses the water level difference of the cathode side catch tank 26 as a parameter. A correction coefficient Y is set according to the water level difference, and this correction coefficient map is stored in advance in the electronic control unit 50. Store in the means.

Next, cathode humidity determination processing when correction is performed based on the water level difference of the cathode catch tank 26 will be described with reference to the flowchart of FIG. This cathode humidity determination process is repeatedly executed by the electronic control unit 50 at regular intervals.
First, in step S01, the current air pump intake air temperature T1 detected by the intake air temperature sensor 31, the current atmospheric pressure P detected by the atmospheric pressure sensor 30, and the current humidification detected by the humidifier inlet temperature sensor 32. The humidifier inlet air humidity A is searched based on the humidifier inlet air temperature T2 with reference to the humidifier inlet air humidity map of FIG.

  Next, the process proceeds to step S02, and the cathode outlet air shown in FIG. 4 is based on the current cathode outlet air temperature T3 detected by the cathode outlet temperature sensor 33 and the current refrigerant outlet temperature T4 detected by the refrigerant outlet temperature sensor 34. The cathode exit air humidity B is searched with reference to the humidity map.

Next, the process proceeds to step S03, and the cathode humidity Hc (temporary cathode humidity) is retrieved based on the humidifier inlet air humidity A and the cathode outlet air humidity B with reference to the cathode humidity map of FIG.
Next, it progresses to step S04 and it is determined whether the cathode humidity Hc obtained by the process of step S03 is less than 60%.
If the determination result in step S04 is “NO” (60% or more), the process proceeds to step S05 to determine whether or not the cathode humidity Hc obtained by the process in step S03 exceeds 80%.

  If the determination result in step S05 is “NO” (80% or less), the process proceeds to step S06, and the cathode humidity Hc is 60% to 80%. Therefore, the cathode is in a standard state in which it is neither dry nor wet. The corrected cathode humidity Hc is calculated by multiplying the cathode humidity Hc obtained in step S03 by the correction coefficient Y, and the execution of this routine is temporarily terminated. The correction coefficient Y is based on the difference in water level between the actual water level of the cathode-side catch tank 26 and the reference water level detected by the water level sensor 27 immediately before the drain valve 28 is opened. Search and decide.

  If the determination result in step S04 is “YES” (less than 60%), the process proceeds to step S07, where it is determined that the cathode is in a dry state, and the cathode humidity Hc obtained in step S03 is multiplied by the correction coefficient Y. Then, the corrected cathode humidity Hc is calculated, and the execution of this routine is once ended. The correction coefficient Y is based on the difference in water level between the actual water level of the cathode-side catch tank 26 and the reference water level detected by the water level sensor 27 immediately before the drain valve 28 is opened. Search and decide.

If the determination result in step S05 is “YES” (exceeds 80%), the process proceeds to step S08, where it is determined that the cathode is in a wet state, and the correction coefficient is added to the cathode humidity Hc obtained in step S03. Multiply by Y to calculate the corrected cathode humidity Hc, and the execution of this routine is temporarily terminated. The correction coefficient Y is based on the difference in water level between the actual water level of the cathode-side catch tank 26 and the reference water level detected by the water level sensor 27 immediately before the drain valve 28 is opened. Search and decide.
Here, the correction coefficient map shown in FIG. 7 may be the same map for the standard state, the dry state, and the wet state, or may be a dedicated map that is different from each other in the standard state, the dry state, and the wet state.

  Thus, when the provisional cathode humidity Hc obtained by searching the cathode humidity map of FIG. 5 is corrected by multiplying by the correction coefficient Y, the cathode humidity Hc close to the true value is estimated in real time. Can do. Further, it is possible to grasp the wet state of the solid polymer electrolyte membrane of the fuel cell stack very accurately based on the estimated value of the cathode humidity Hc.

As a result, by controlling the operation of the fuel cell stack 1 based on the cathode humidity Hc, it becomes possible to appropriately execute cathode humidity management. For example, when the cathode humidity is in a dry region, the current taken out from the fuel cell stack 1 is suppressed to prevent power concentration due to insufficient humidity in the single cell surface, or to increase the cathode humidity. The cathode humidity can be optimized.
In addition, even when the fuel cell system has been stopped for a long time, the cathode humidity can be grasped from the moment of startup, so that the startup control of the fuel cell stack according to the cathode humidity at that time becomes possible and power generation is possible. It is possible to shift to an easy environment.

<Example 2>
Next, a second embodiment of the fuel cell system and the method for determining the membrane wet state of the fuel cell system according to the present invention will be described with reference to the drawings of FIGS.
FIG. 8 is a schematic configuration diagram of the fuel cell system according to the second embodiment. Since the basic configuration of the fuel cell system is the same as that of the first embodiment, the same reference numerals are given to the same mode portions and the description thereof will be omitted, and only the differences from the first embodiment will be described below.

In the fuel cell system of the second embodiment, the cathode-side catch tank 26 is not provided in the air off-gas passage 5.
In the fuel cell system of Example 2, the hydrogen offgas recovery passage 12 is provided with an anode-side catch tank (anode drainage water storage unit) 13 that temporarily stores condensed water of water contained in the hydrogen offgas. 11 is supplied with hydrogen off-gas from which moisture has been removed.

The anode side catch tank 13 is provided with a water level sensor 41 for measuring the water level of the stored water. The anode side catch tank 13 is connected to the dilution box 6 via a drain passage 17 having a drain valve 16, and the drain valve 16 is set at every predetermined time set according to the operating state of the fuel cell stack 1. The water accumulated in the catch tank 13 is drained to the dilution box 6.
In the fuel cell system of Example 2, the hydrogen offgas purge passage 15 provided with the purge valve 14 branches from the hydrogen offgas recovery passage 12 downstream of the catch tank 13.

  As described above, by using the humidifier inlet air humidity map of FIG. 3, the cathode outlet air humidity map of FIG. 4, and the anode humidity map of FIG. 10, the atmospheric pressure P, the air pump intake air temperature T1, and the humidifier inlet air Based on the temperature T2, the cathode outlet air temperature T3, and the refrigerant outlet temperature T4, the anode humidity Ha in the fuel cell stack 1 can be predicted.

  In the second embodiment, the anode humidity Ha predicted based on the map is set as a temporary anode humidity, and the moisture state inside the fuel cell stack 1 in the currently operating fuel cell system is compared with the temporary anode humidity. By performing the corresponding correction, the anode humidity Ha closer to the true value can be estimated in real time.

A correction method for the temporary anode humidity in the second embodiment will be described.
There is a correlation between the amount of condensed water per unit time of hydrogen offgas and the anode humidity of the fuel cell stack. The higher the anode humidity, the greater the amount of condensed water per unit time of hydrogen offgas. Therefore, in Example 2, the amount of dew condensation water of hydrogen off-gas at a predetermined time is measured, and this is compared with the amount of dew condensation water (reference dew condensation water amount) as a reference when the anode humidity is in a standard humidified state (for example, humidity 50%). Then, a correction coefficient was obtained from the comparison value to correct the temporary anode humidity.

Specifically, the dew condensation water of hydrogen off gas is stored in the anode side catch tank 13, and the drain valve 16 is opened and drained at a predetermined interval according to the operation state of the fuel cell stack 1, so that the anode before draining From the water level of the side catch tank 13, the amount of dew condensation water of the hydrogen off gas during a predetermined time (during the interval) can be obtained.
The opening / closing timing of the drain valve 16 and the temporal change in the water level of the water stored in the anode side catch tank 13 are the same as in the case of the cathode side catch tank 26 shown in the time chart of FIG.

  On the other hand, since the amount of condensed water per unit time of the air off gas when the fuel cell stack 1 is in the steady operation state and the anode humidity is in the standard humidified state is experimentally known, the time of the interval is added to this known amount of condensed water. By multiplying, the reference dew condensation water amount can be obtained, and since the size of the anode side catch tank 13 is known in advance, the water level at that time (reference water level) can also be calculated.

  In the second embodiment, instead of comparing the amount of condensed water stored in the anode side catch tank 13, the water level of the condensed water stored in the anode side catch tank 13 is compared. When the water level of 13 is larger than the reference water level, it is estimated that the anode humidity is higher than the standard humidified state. In this case, the correction coefficient Y is set so as to increase, and the actual anode-side catch tank When the water level of 13 is smaller than the reference water level, it is estimated that the humidity of the anode is lower than the standard humidification state. In this case, the correction coefficient Y is set so as to decrease.

In order to realize this, as described above, the water level sensor 41 is provided in the anode side catch tank 13, and the output signal of the water level sensor 41 is output to the electronic control device 50. A correction coefficient map is stored in which the water level difference of the anode side catch tank 13 prepared in advance is used as a parameter.
The correction coefficient map using the water level difference of the anode side catch tank 13 as a parameter is the same as the correction coefficient map using the water level difference of the cathode side catch tank 26 in the above-described first embodiment as a parameter. Therefore, the description is omitted.

Next, anode humidity determination processing will be described with reference to the flowchart of FIG. This anode humidity determination process is repeatedly executed by the electronic control unit 50 at regular intervals.
First, in step S101, the current air pump intake air temperature T1 detected by the intake air temperature sensor 31, the current atmospheric pressure P detected by the atmospheric pressure sensor 30, and the current humidification detected by the humidifier inlet temperature sensor 32. The humidifier inlet air humidity A is searched based on the humidifier inlet air temperature T2 with reference to the humidifier inlet air humidity map of FIG.

  Next, the process proceeds to step S102, where the cathode outlet air shown in FIG. 4 is based on the current cathode outlet air temperature T3 detected by the cathode outlet temperature sensor 33 and the current refrigerant outlet temperature T4 detected by the refrigerant outlet temperature sensor 34. The cathode exit air humidity B is searched with reference to the humidity map.

Next, the process proceeds to step S103, and the anode humidity Ha (temporary anode humidity) is retrieved based on the humidifier inlet air humidity A and the cathode outlet air humidity B with reference to the anode humidity map of FIG.
Next, it progresses to step S104 and it is determined whether the anode humidity Ha obtained by the process of step S103 is less than 40%.
If the determination result in step S104 is “NO” (40% or more), the process proceeds to step S105, and it is determined whether or not the anode humidity Ha obtained by the process in step S103 exceeds 60%.

  If the determination result in step S105 is “NO” (60% or less), the process proceeds to step S106, and the anode humidity Ha is 40% to 60%, so that the anode is in a standard state in which it is neither dry nor wet. The corrected anode humidity Hc is calculated by multiplying the anode humidity Ha obtained in step S103 by the correction coefficient Y, and the execution of this routine is temporarily terminated. The correction coefficient Y is based on the water level difference between the actual water level of the anode side catch tank 13 detected by the water level sensor 41 and the reference water level immediately before the drain valve 16 is opened, and the water level difference in the anode side catch tank 13. The correction coefficient map is used as a parameter to search and determine.

  If the determination result in step S104 is “YES” (less than 40%), the process proceeds to step S107, where it is determined that the anode is in a dry state, and the anode humidity Ha obtained in step S103 is multiplied by the correction coefficient Y. Then, the corrected anode humidity Ha is calculated, and the execution of this routine is temporarily terminated. The correction coefficient Y is based on the water level difference between the actual water level of the anode side catch tank 13 detected by the water level sensor 41 and the reference water level immediately before the drain valve 16 is opened, and the water level difference in the anode side catch tank 13. The correction coefficient map is used as a parameter to search and determine.

When the determination result in step S105 is “YES” (exceeds 60%), the process proceeds to step S108, where it is determined that the anode is in a wet state, and the correction coefficient is added to the anode humidity Ha obtained in step S103. Multiply by Y to calculate the corrected anode humidity Ha, and the execution of this routine is temporarily terminated. The correction coefficient Y is based on the water level difference between the actual water level of the anode side catch tank 13 detected by the water level sensor 41 and the reference water level immediately before the drain valve 16 is opened, and the water level difference in the anode side catch tank 13. The correction coefficient map is used as a parameter to search and determine.
In the second embodiment, the electronic control unit 50 constitutes an anode humidity calculating means.

  Here, the correction coefficient map using the water level difference of the anode-side catch tank 13 as a parameter may be the same map for the standard state, the dry state, and the wet state, or dedicated maps that are different from each other in the standard state, the dry state, and the wet state. It is good.

  As described above, when the provisional anode humidity Ha obtained by searching the anode humidity map in FIG. 10 is corrected by multiplying by the correction coefficient Y using the water level difference of the anode side catch tank 13 as a parameter, true The anode humidity Ha close to the value can be estimated in real time. Further, the wet state of the solid polymer electrolyte membrane of the fuel cell stack can be grasped very accurately based on the estimated value of the anode humidity Ha.

As a result, by controlling the operation of the fuel cell stack 1 based on the anode humidity Ha, it becomes possible to appropriately perform the humidity management of the anode. For example, when the anode humidity is in a dry region, by suppressing the current taken out from the fuel cell stack 1, power concentration due to insufficient humidity in the single cell plane can be prevented in advance, or the anode humidity can be increased. The anode humidity can be optimized.
In addition, even when the fuel cell system has been stopped for a long time, the anode humidity can be grasped from the moment when it is started, so the start-up control of the fuel cell stack according to the anode humidity at that time becomes possible, and power generation is possible. It is possible to shift to an easy environment.

<Example 3>
Next, Embodiment 3 of the fuel cell system according to the present invention and the film wet state determination method of the fuel cell system will be described with reference to the drawing of FIG.
FIG. 11 is a configuration diagram of a main part of the fuel cell system according to the third embodiment. The basic configuration of the fuel cell system is the same as that of the second embodiment, and FIG. 11 is a diagram showing only the parts different from the fuel cell system of the second embodiment.
Only differences from the second embodiment will be described below.

In the fuel cell system of Example 3, the anode / cathode side catch tank 26 is not provided in the hydrogen off-gas recovery path 12.
In the fuel cell system of the third embodiment, a hydrogen pump 42 is provided in the hydrogen off-gas recovery path 12, and the hydrogen off-gas discharged from the anode of the fuel cell stack 1 is boosted by the hydrogen pump 42 and supplied to the ejector 11. It is comprised so that. Examples of the hydrogen pump 42 include positive displacement pumps (rotary type, roots type) and turbo type pumps.

  As described above, when the hydrogen pump 42 is provided in the hydrogen off-gas recovery path 12, moisture in the hydrogen off-gas is condensed in the hydrogen pump 42, and the condensed water is accumulated in the hydrogen pump 42. Therefore, a water level sensor 43 for detecting the water level of the condensed water accumulated in the hydrogen pump 42 is provided in the hydrogen pump 42, and the hydrogen pump 42 is connected to the dilution box 6 through a drain passage 45 having a drain valve 44. Then, the drain valve 44 is controlled to open at every predetermined time set according to the operating state of the fuel cell stack 1, and the water accumulated in the hydrogen pump 42 is drained into the dilution box 6.

  In Example 3, the portion of the hydrogen supply passage 8 downstream from the ejector 11 and the hydrogen off-gas recovery passage 12 constitute an anode reaction gas circulation passage, and the hydrogen pump 42 serves as the anode reaction gas circulation passage. Is provided.

  If comprised in this way, it will replace with the water level of the water collected in the anode side catch tank 13 in Example 2, and will correct | amend with respect to temporary anode humidity based on the water level accumulated in the hydrogen pump 42 in Example 3. It becomes possible. Since the principle of correction for the temporary anode humidity is the same as that in the second embodiment, the description thereof is omitted.

  In the third embodiment, the difference in water level between the actual water level accumulated in the hydrogen pump 42 and the reference water level accumulated in the hydrogen pump 42 when the fuel cell stack 1 is in the steady operation state and the anode humidity is in the standard humidification state is a parameter. A correction coefficient map is created and stored in the storage means of the electronic control unit 50 in advance.

Then, based on the water level difference between the actual water level of the hydrogen pump 42 detected by the water level sensor 43 immediately before the drain valve 44 is opened and the reference water level of the hydrogen pump 42, the correction coefficient map using the water level difference as a parameter. Then, the correction coefficient Y is determined, and the corrected anode humidity is calculated by multiplying the temporary anode humidity by this correction coefficient Y.
The anode humidity determination process in the third embodiment is the same as the anode humidity determination process in the second embodiment shown in the flowchart of FIG.

  Also in the case of the third embodiment, correction is performed by multiplying the temporary anode humidity Ha obtained by searching the anode humidity map of FIG. 10 by the correction coefficient Y using the water level difference of the hydrogen pump 42 as a parameter. Then, the anode humidity Ha close to the true value can be estimated in real time. Further, the wet state of the solid polymer electrolyte membrane of the fuel cell stack can be grasped very accurately based on the estimated value of the anode humidity Ha.

  As a result, by controlling the operation of the fuel cell stack 1 based on the anode humidity Ha, it becomes possible to appropriately perform the humidity management of the anode. For example, when the anode humidity is in a dry region, by suppressing the current taken out from the fuel cell stack 1, power concentration due to insufficient humidity in the single cell plane can be prevented in advance, or the anode humidity can be increased. The anode humidity can be optimized.

In addition, even when the fuel cell system has been stopped for a long time, the anode humidity can be grasped from the moment when it is started, so the start-up control of the fuel cell stack according to the anode humidity at that time becomes possible, and power generation is possible. It is possible to shift to an easy environment.
It should be noted that the dew condensation water contained in the hydrogen off gas is temporarily stored in the anode catch tank 13 in the second embodiment, and temporarily stored in the liquid reservoir of the hydrogen pump 42 in the third embodiment. Although the amount of water was measured, instead of these, a liquid reservoir part for condensing condensed water of hydrogen offgas was formed in the pipe constituting the hydrogen offgas recovery path 12, and based on the water level accumulated in this liquid reservoir part. It is also possible to calculate the corrected anode humidity by determining the correction coefficient Y and multiplying the temporary anode humidity by this correction coefficient Y.

  The membrane wet state of the fuel cell stack 1 can be determined by executing either the cathode humidity determination process or the anode humidity determination process.

1 Fuel cell stack (fuel cell)
5 Air off-gas passage (cathode discharge passage)
8 Hydrogen supply passage (Anode reaction gas circulation passage)
12 Hydrogen off-gas recovery path (anode discharge flow path, anode reaction gas circulation flow path)
13 Anode side catch tank (anode discharge water storage part)
26 Cathode side catch tank (cathode discharge water reservoir)
27 Water level sensor (water level measuring means)
30 Atmospheric pressure sensor (environmental condition measuring means)
31 Intake air temperature sensor (environmental condition measurement means)
32 Humidifier inlet temperature sensor (Fuel cell stack temperature condition measuring means)
33 Cathode outlet temperature sensor (Fuel cell stack temperature condition measuring means)
34 Refrigerant outlet temperature sensor (Fuel cell stack temperature condition measuring means)
41 Water level sensor (water level measuring means)
42 Hydrogen pump (fuel pump)
43 Water level sensor (water level measuring means)
50 Electronic control device (cathode humidity calculation means, anode humidity calculation means)

Claims (5)

A fuel cell having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas;
A cathode discharge passage through which a cathode off-gas discharged from the cathode of the fuel cell flows;
A cathode discharge water storage section that is provided in the cathode discharge flow path and temporarily stores condensed water of moisture contained in the cathode off gas;
Water level measuring means for measuring the water level of the cathode discharge water storage section;
Environmental condition measuring means for measuring environmental conditions of the fuel cell;
Fuel cell temperature condition measuring means for measuring the temperature condition of the fuel cell;
Cathode humidity calculating means for calculating the humidity of the cathode based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means;
With
The cathode humidity calculation means includes
A determination value calculation unit that calculates two determination values based on the environmental condition value measured by the environmental condition measurement unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measurement unit;
A provisional cathode humidity calculation unit for obtaining provisional humidity of the cathode from the two determination values;
Correction coefficient calculation for obtaining a correction coefficient based on a comparison value between the actual water level of the cathode discharge water storage unit measured by the water level measuring means and the reference water level of the cathode discharge water storage unit in the steady operation state of the fuel cell And
A cathode humidity correction unit that determines the humidity of the cathode by multiplying the temporary cathode humidity determined by the temporary cathode humidity calculation unit by the correction coefficient determined by the correction coefficient calculation unit;
A fuel cell system comprising: A fuel cell having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas;
An anode discharge passage through which anode off-gas discharged from the anode of the fuel cell flows;
An anode discharge water storage section that is provided in the anode discharge flow path and temporarily stores condensed water of moisture contained in the anode off gas;
Water level measuring means for measuring the water level of the anode discharge water storage section;
Environmental condition measuring means for measuring environmental conditions of the fuel cell;
Fuel cell temperature condition measuring means for measuring the temperature condition of the fuel cell;
An anode humidity calculating means for calculating the humidity of the anode based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means;
With
The anode humidity calculating means includes
A determination value calculation unit that calculates two determination values based on the environmental condition value measured by the environmental condition measurement unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measurement unit;
A temporary anode humidity calculator for determining the temporary humidity of the anode from the two determination values;
Correction coefficient calculation for obtaining a correction coefficient based on a comparison value between the actual water level of the anode discharge water storage unit measured by the water level measurement means and the reference water level of the anode discharge water storage unit in a steady operation state of the fuel cell And
An anode humidity correction unit for determining the humidity of the anode by multiplying the temporary anode humidity determined by the temporary anode humidity calculation unit by the correction coefficient determined by the correction coefficient calculation unit;
A fuel cell system comprising: A fuel cell having an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas;
An anode reaction gas circulation flow path for returning the anode off-gas discharged from the anode of the fuel cell to the anode of the fuel cell;
A fuel pump provided in the anode reaction gas circulation flow path;
A water level measuring means for measuring the water level of a reservoir in which condensed water of water contained in the anode off gas temporarily accumulates in the fuel pump;
Environmental condition measuring means for measuring environmental conditions of the fuel cell;
Fuel cell temperature condition measuring means for measuring the temperature condition of the fuel cell;
An anode humidity calculating means for calculating the humidity of the anode based on the environmental condition value measured by the environmental condition measuring means and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring means;
With
The anode humidity calculating means includes
A determination value calculation unit that calculates two determination values based on the environmental condition value measured by the environmental condition measurement unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measurement unit;
A temporary anode humidity calculator for determining the temporary humidity of the anode from the two determination values;
A correction coefficient calculation unit for obtaining a correction coefficient based on a comparison value between the actual water level of the storage unit measured by the water level measuring unit and the reference water level of the storage unit in a steady operation state of the fuel cell;
An anode humidity correction unit for determining the humidity of the anode by multiplying the temporary anode humidity determined by the temporary anode humidity calculation unit by the correction coefficient determined by the correction coefficient calculation unit;
A fuel cell system comprising: A fuel cell comprising an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas, environmental condition measuring means for measuring environmental conditions of the fuel cell, and temperature conditions of the fuel cell A method of determining a wet state of the solid polymer electrolyte membrane in a fuel cell system comprising: a fuel cell temperature condition measuring means for measuring;
A determination value calculating step for obtaining two determination values based on the environmental condition value measured by the environmental condition measuring unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring unit;
A provisional cathode humidity calculation step of obtaining a provisional humidity of the cathode based on the two determination values using a map created in advance;
Based on a comparison value between the actual amount of condensed water contained in the cathode offgas discharged from the cathode of the fuel cell and the reference amount of condensed water contained in the cathode offgas in the steady operation state of the fuel cell. A correction coefficient calculation step for obtaining a correction coefficient by
A cathode humidity correction step of obtaining the cathode humidity by multiplying the provisional humidity of the cathode by the correction coefficient;
A method for determining a wet state of a membrane of a fuel cell system, wherein the wet state of the solid polymer electrolyte membrane is determined in order. A fuel cell comprising an anode and a cathode sandwiching a solid polymer electrolyte membrane and generating power by being supplied with a reaction gas, environmental condition measuring means for measuring environmental conditions of the fuel cell, and temperature conditions of the fuel cell A method of determining a wet state of the solid polymer electrolyte membrane in a fuel cell system comprising: a fuel cell temperature condition measuring means for measuring;
A determination value calculating step for obtaining two determination values based on the environmental condition value measured by the environmental condition measuring unit and the temperature condition value of the fuel cell measured by the fuel cell temperature condition measuring unit;
A temporary anode humidity calculation step of obtaining a temporary humidity of the anode based on the two determination values using a map created in advance;
Based on a comparison value between the actual amount of condensed water of moisture contained in the anode off gas discharged from the anode of the fuel cell and the reference amount of condensed water of moisture contained in the anode off gas in the steady operation state of the fuel cell. A correction coefficient calculation step for obtaining a correction coefficient by
An anode humidity correction step for determining the humidity of the anode by multiplying the provisional humidity of the anode by the correction coefficient;
A method for determining a wet state of a membrane of a fuel cell system, wherein the wet state of the solid polymer electrolyte membrane is determined in order.

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