JP2006260882A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system for quickly detecting the deterioration of an electrolyte film. <P>SOLUTION: The first amount of cooling water heat reception is calculated, based on inflow gas total enthalpy and exhaust gas total enthalpy. The inflow gas total enthalpy is the sum of the enthalpy of fuel gas supplied to an anode electrode and that of air supplied to a cathode electrode. The exhaust gas total enthalpy is the sum of the enthalpy of discharge fuel gas discharged from the anode electrode and that of discharge air discharged from the cathode electrode. When the difference in a fuel cell 1 between the first amount of cooling water heat reception of cooling water and the second amount of cooling water heat reception is larger than a prescribed value, it is determined that the electrolyte film has deteriorated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to determination of deterioration of an electrolyte membrane.

  In the fuel cell, the solid polymer electrolyte membrane has a function of permeating hydrogen ions (protons) and a function of separating the anode fuel gas (hydrogen) and the cathode oxidant gas (air). Therefore, when the solid polymer electrolyte membrane deteriorates, for example, when pores are opened, the anode fuel gas may leak to the cathode, or the cathode oxidant gas may leak to the anode. The fuel gas and oxidant gas react to generate heat, which may deteriorate the fuel cell and reduce the power generation efficiency of the fuel cell.

  Therefore, in the fuel cell, when hydrogen leakage or oxidant gas leakage occurs due to deterioration of the solid polymer electrolyte membrane, this must be detected at an early stage, and necessary measures such as replacement of the solid polymer electrolyte membrane must be taken.

Therefore, conventionally, as disclosed in Patent Document 1, the output voltage is measured in the activation overvoltage region while maintaining the pressure of the fuel gas supplied to the anode higher than the pressure of the oxidant gas supplied to the cathode. However, when the output voltage is equal to or lower than the predetermined voltage value, it is determined that gas leakage has occurred.
JP 2003-045466 A

  However, the above-described invention has a problem that the deterioration of the electrolyte membrane cannot be accurately determined in a region other than the activation overvoltage region, for example, when the load is larger than that in the activation overvoltage region.

  The present invention has been invented to solve such problems, and aims to determine the deterioration of the electrolyte membrane regardless of the power generation region of the fuel cell, that is, the load required for the fuel cell. To do.

  In the present invention, a fuel cell that generates power by supplying fuel gas and oxidant gas to the electrolyte membrane, and a first heat amount that calculates a first heat amount equivalent value of the fuel gas and oxidant gas supplied to the fuel cell. Equivalent value calculating means, second heat quantity equivalent value calculating means for calculating a second heat quantity equivalent value of the fuel gas and oxidant gas discharged from the fuel cell, a first heat quantity equivalent value, and a second heat quantity. A heat amount equivalent value change amount calculating means for calculating a change amount of a heat amount equivalent value in the fuel cell based on the equivalent value, and a cooling water heat amount for calculating a cooling water heat amount change amount in the fuel cell for cooling water for cooling the fuel cell Change amount calculation means, and electrolyte membrane deterioration determination means for determining that the electrolyte membrane has deteriorated when the difference between the change amount of the heat amount equivalent value and the heat amount change amount of the cooling water is equal to or greater than a predetermined value.

  According to the present invention, the calorific value equivalent of the fuel gas and oxidant gas supplied to the fuel cell, such as enthalpy, and the calorific value equivalent of the fuel gas and oxidant gas discharged from the fuel cell, such as enthalpy, are calculated and cooled. Calculate the amount of heat change in the water fuel cell. When the difference between the change amount based on the value corresponding to the amount of heat in the fuel cell and the heat change amount of the cooling water is larger than a predetermined value, it is determined that the electrolyte membrane has deteriorated. Thereby, in the fuel cell system, it is possible to determine the deterioration of the electrolyte membrane regardless of the power generation region of the fuel cell, and it is possible to quickly detect when the electrolyte membrane is deteriorated. That is, it is possible to determine the deterioration of the electrolyte membrane regardless of the load required for the fuel cell system. Particularly when the load required for the fuel cell system is large, it is possible to accurately determine the deterioration of the electrolyte membrane.

  A fuel cell system according to an embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG.

  The fuel cell system controls the fuel cell 1, a hydrogen cylinder 2 that supplies hydrogen to an anode electrode 32, which will be described later, via a hydrogen supply path 20, and a hydrogen flow rate that is provided in the hydrogen supply path 20 and supplied from the hydrogen cylinder 2. A flow rate control valve 3, a drain trap 4 provided in the hydrogen circulation path 21 for circulating the discharged hydrogen discharged from the anode electrode 32 to the anode electrode 32 again, and a circulation pump 5 provided downstream of the drain trap 4 are provided. Further, when the nitrogen concentration in the discharged hydrogen discharged from the anode electrode 32 becomes high, the anode electrode 32 communicates with the outside of the fuel cell system in the hydrogen discharge path 25 for discharging the discharged hydrogen to the outside of the fuel cell system. A switching valve 12 for switching the state is provided. Hereinafter, the gas containing hydrogen to be supplied to the anode electrode 32, that is, the hydrogen supplied from the hydrogen cylinder 2 and the exhausted hydrogen circulated by the hydrogen circulation path 21 are collectively referred to as fuel gas.

  When the fuel cell system is operated, nitrogen is mixed from the cathode electrode 33 to the anode electrode 32 through the electrolyte membrane 31. As a result, when the nitrogen concentration in the fuel gas increases, the power generation efficiency of the fuel cell 1 decreases. Therefore, when the nitrogen concentration in the fuel gas increases, the switching valve 12 provided in the hydrogen discharge path 25 is opened and discharged from the anode electrode 32. The discharged fuel gas is discharged outside the fuel cell system. In this embodiment, the concentration of nitrogen in the fuel gas is estimated by the integrated value of the amount of mixed nitrogen converted from the pressure difference between the anode and the cathode of the fuel cell 1, and the switching valve 12 is controlled to open and close. The opening / closing control of the switching valve 12 is not limited to this.

  A compressor 6 for supplying air to the cathode electrode 33 to be described later via the air supply path 22; a drain trap 7 provided in the air discharge path 23 for discharging exhaust air from the cathode electrode 33 to the outside of the fuel cell system; A pressure control valve 8 for controlling the pressure of the cathode 41 is provided. Further, a radiator 9 provided in a cooling water circulation path 24 for circulating the cooling water in the fuel cell 1 and adjusting the temperature of the cooling water, and a cooling water pump 10 for circulating the cooling water between the fuel cell 1 and the radiator 9 are provided. Prepare.

  In addition, a fuel cell case 11 is provided so as to prevent foreign matters such as dust from entering the fuel cell 1 from the outside. The fuel cell case 11 is desirably made of a highly heat-insulating member.

  The fuel cell 1 is configured by stacking, for example, 100 to 200 unit cells 30. Here, the configuration of the unit cell 30 will be described with reference to the schematic configuration diagram of FIG.

  The unit cell 30 includes a solid polymer electrolyte membrane (hereinafter referred to as an electrolyte membrane) 31, an anode electrode 32 and a cathode electrode 33 that sandwich the electrolyte membrane 31, and an anode provided further outside the anode electrode 32 and the cathode electrode 33. A separator 34 and a cathode separator 35 are included.

  The anode electrode 32 and the cathode electrode 33 are composed of a catalyst layer (not shown) having a catalyst such as platinum and a gas diffusion layer (not shown) having conductivity and diffusing fuel gas or air.

  The anode separator 34 includes a hydrogen flow path 36 that communicates with the hydrogen supply path 20 and the hydrogen circulation path 21 and supplies fuel gas to the anode electrode 32, and the cathode separator 35 communicates with the air supply path 22 and the air discharge path 23. An air flow path 37 for supplying air to the cathode electrode 33 is provided. Further, a cooling water flow path 38 is provided which communicates with the cooling water circulation path 24 and through which cooling water for cooling the unit cell 30 flows.

  The drain traps 4 and 7 condense moisture in the exhaust fuel gas or exhaust air. The flow rate of the condensed water is detected by liquid water flow rate sensors (flow rate sensors) F2 and F4 provided in the drain traps 4 and 7, respectively.

  The hydrogen supply path 20 includes a flow rate sensor F1 that detects the flow rate of the fuel gas supplied to the anode electrode 32, a dew point sensor (humidity detection sensor) D1 that detects humidity, and a temperature sensor T1 that detects temperature. A dew point sensor (humidity detection sensor) D2 that detects the humidity of the discharged fuel gas discharged from the anode electrode 32 on the downstream side of the anode electrode 32 in the hydrogen circulation path 21 and upstream of the drain trap 4, and detects the temperature Temperature sensor T2 is provided.

  The air supply path 22 includes a flow rate sensor F3 that detects the flow rate of air supplied to the cathode electrode 33, a dew point sensor (humidity detection sensor) D3 that detects humidity, and a temperature sensor T3 that detects temperature. A dew point sensor (humidity detection sensor) D4 that detects the humidity of the exhaust air discharged from the cathode electrode 33 on the downstream side of the cathode electrode 33 in the air discharge path 23 and upstream of the drain trap 7 detects the temperature. A temperature sensor T4 is provided.

  The cooling water supply circuit 24 includes a flow rate sensor F5 that detects the circulating flow rate of the cooling water and a temperature sensor T5 that detects the temperature of the cooling water supplied to the cooling water flow channel 38. In addition, a temperature sensor T6 that detects the temperature of the cooling water discharged from the cooling water flow path 38 is provided.

  Inside the fuel cell case 11, a temperature sensor T7 for detecting the ambient temperature of the fuel cell 1 is provided.

  In order to detect the power generation state of the fuel cell 1, a voltage sensor V1 that detects the voltage of the fuel cell 1 and a current sensor I1 that detects the current of the fuel cell 1 are provided.

  A calculation device 40 is provided that calculates a first cooling water heat receiving amount and a second cooling water heat receiving amount, which will be described later, from signals from each sensor and the like, and determines whether the electrolyte membrane 31 is deteriorated.

  With the above configuration, it is possible to detect the mixing of fuel gas into the cathode electrode 33 or the mixing of air into the anode electrode 32 due to deterioration of the electrolyte membrane 31.

  Next, a method for determining deterioration of the electrolyte membrane 31 of the present invention will be described with reference to the flowchart of FIG.

  In step S100, an inflow gas total enthalpy (first heat quantity equivalent value) that is a total value of the enthalpy of the fuel gas supplied to the anode electrode 32 and the enthalpy of the air supplied to the cathode electrode 33 is calculated (step S100). Constitutes a first heat quantity equivalent value calculation means).

  In step S101, the exhaust gas total enthalpy (second heat amount equivalent value) that is the total value of the enthalpy of the exhaust fuel gas exhausted from the anode electrode 32 and the enthalpy of the exhaust air exhausted from the cathode electrode 33 is calculated. (Step S101 constitutes a second heat quantity equivalent value calculating means).

  The calculation method of the inflow gas total enthalpy and the exhaust gas total enthalpy will be described in detail later.

The heat balance of the fuel cell system is determined by the total enthalpy of inflow gas, the total enthalpy of exhaust gas, the power generated by the fuel cell 1, and the heat generation amount of the fuel cell 1.
Inflow gas total enthalpy = exhaust gas total enthalpy + fuel cell generated power + fuel cell calorific value (1)
Can be represented by The calorific value of the fuel cell 1 is
Amount of heat generated by the fuel cell = amount of heat received from the cooling water + amount of heat released from the fuel cell (2)
Can be represented by

In other words, the amount of heat received from the cooling water is calculated from the equations (1) and (2).
Amount of heat received from cooling water = total enthalpy of inflow-total enthalpy of exhaust gas-generated power of fuel cell-heat dissipation of fuel cell (3)
Can be represented by In the following description, the amount of heat received by the cooling water represented by the expression (3) is defined as a first amount of heat received by the cooling water (amount of change in the value corresponding to the amount of heat).

  In step S102, the generated power of the fuel cell 1 and the heat radiation amount of the fuel cell 1 are calculated, and the first equation (3) is calculated from the inflow gas total enthalpy calculated in step S100 and the exhaust gas total enthalpy calculated in step S101. (Step S102 constitutes a heat amount equivalent value change amount calculation means). The power generated by the fuel cell is calculated from the product of the voltage detected by the voltage sensor V1 and the current detected by the current sensor I1. Further, the heat radiation amount of the fuel cell 1 is set in advance by experiments or the like, and is calculated from a map or the like based on the temperature sensor T7 and the generated power of the fuel cell 1.

In step S103, the amount of heat received by the cooling water based on the temperature change in the fuel cell 1 of the cooling water flowing through the cooling water flow path 38 is calculated as follows:
Cooling water heat receiving amount = cooling water flow rate × cooling water specific gravity × cooling water specific heat × (cooling water discharge temperature−cooling water supply temperature) (4)
Calculated by In the following, the amount of heat received by the cooling water represented by the equation (4) is defined as the second amount of heat received by the cooling water (the amount of change in the amount of cooling water).

  In step S103, the flow rate of the cooling water is detected by the flow rate sensor F5, the temperature upstream of the cooling water flow path 38, that is, the cooling water supply temperature is detected by the temperature sensor T5, and the temperature downstream of the cooling water flow path 38 is detected by the temperature sensor T6. That is, the cooling water discharge temperature is detected. Then, the second cooling water heat receiving amount is calculated from the preset cooling water specific gravity and the cooling water specific heat by Equation (4) (step S103 constitutes the cooling water heat amount change calculating means).

  When a normal operation is performed in the fuel cell system in which the electrolyte membrane 31 is not deteriorated, the values of the first cooling water heat receiving amount and the second cooling water heat receiving amount are substantially the same. However, when the electrolyte membrane 31 deteriorates and pores are opened in the electrolyte membrane 31 and air is mixed into the anode electrode 32 or hydrogen is mixed into the cathode electrode 33, hydrogen and hydrogen are formed on the catalyst layer of the anode electrode 32 or the cathode electrode 33. Oxygen reacts and the amount of heat received by the second cooling water is increased by the reaction heat. Therefore, the second cooling water heat reception amount is larger than the first cooling water heat reception amount.

  In step S104, a difference between the second cooling water heat reception amount calculated in step S103 and the first cooling water heat reception amount calculated in step S102 is calculated, and it is determined whether the difference is larger than a predetermined value. The predetermined value is a value set in advance by experiments or the like, and is a difference in heat amount between the second cooling water heat reception amount and the first cooling water heat reception amount that occurs when the electrolyte membrane 31 deteriorates. Calculate with a map etc. according to the required load.

  In step S104, if it is determined that the electrolyte membrane 31 has deteriorated, a warning lamp (not shown) or the like is notified to the driver or the like. Then, when the difference between the second cooling water heat reception amount and the first heat reception amount is larger than a predetermined value, the process proceeds to step S105. When the difference between the second cooling water heat receiving amount and the first heat receiving amount is smaller than a predetermined value, it is determined that the electrolyte membrane 31 has not deteriorated, and the normal operation of the fuel cell system is continued (step S104). Constitutes electrolyte membrane deterioration determining means).

  In step S105, it is determined that the electrolyte membrane 31 is deteriorated and air is mixed into the anode electrode 32 or hydrogen is mixed into the cathode electrode 33, and the anode electrode 32 and the cathode electrode 3 are The pressure is substantially the same, so that mixing of air into the anode electrode 32 due to deterioration of the electrolyte membrane 31 or mixing of hydrogen into the cathode electrode 33 is suppressed. As a result, further deterioration of the electrolyte membrane 31 can be suppressed, and for example, in a fuel cell system mounted in an automobile, it is possible to prevent the automobile from being disabled.

  Here, FIG. 4 shows an example of a change in the amount of heat received by the cooling water when the electrolyte membrane 31 is deteriorated. When the fuel cell 1 is operated for a long time, deterioration may occur. In this case, the difference between the second cooling water heat reception amount and the first cooling water heat reception amount becomes large during operation of the fuel cell system.

  In this embodiment, the difference between the second cooling water heat receiving amount based on the temperature change of the cooling water in the fuel cell 1 and the first cooling water heat receiving amount based on the change in the enthalpy in the fuel cell 1 is greater than a predetermined value. In such a case (deterioration point a in FIG. 4), deterioration of the electrolyte membrane 31 can be detected.

  As described above, the deterioration determination of the electrolyte membrane 31 can be performed regardless of the load of the fuel cell 1 during the operation of the fuel cell system.

  Next, inflow gas total enthalpy and exhaust gas total enthalpy will be described.

  For example, when the temperature of a substance changes from T1 to T2, the enthalpy H can be calculated by the equation (5).

Where N is the number of moles of the substance, Cp is the constant pressure molar heat capacity, and Cp is
Cp = a + bT + cT ² Formula (6)
And a, b, and c are constants determined by the type of substance.

  In this embodiment, the components of the fuel gas supplied to the anode electrode 32 are hydrogen, nitrogen, and water vapor, and the components of the air supplied to the cathode electrode 33 are nitrogen, oxygen, and water vapor. Further, the components of the exhaust fuel gas discharged from the anode electrode 32 are hydrogen, nitrogen, water vapor, and water, and the components of the exhaust air discharged from the cathode electrode 33 are nitrogen, oxygen, water vapor, and water. It is desirable to consider components other than this constituent component.

  The number of moles of hydrogen in the fuel gas supplied to the anode electrode 32 depends on the number of moles of hydrogen supplied from the hydrogen cylinder 2 according to the load required for the fuel cell system, and the exhaust fuel that circulates in the hydrogen circulation path 21. It is the total value with the number of moles of hydrogen in the gas, and is calculated according to the load required for the fuel cell system. The hydrogen concentration in the fuel gas supplied to the anode electrode 32 may be detected using a hydrogen concentration sensor, and may be calculated from the fuel gas flow rate and the hydrogen concentration detected by the flow rate sensor F1.

  The number of moles of nitrogen in the fuel gas supplied to the anode electrode 32 is calculated based on the integrated value of the amount of mixed nitrogen converted from the differential pressure between the anode and cathode of the fuel cell 1.

  The number of moles of water vapor in the fuel gas supplied to the anode electrode 32 is calculated from the flow rate of the fuel gas detected by the flow rate sensor F1 and the humidity of the fuel gas detected by the dew point sensor D1.

  The number of moles of nitrogen and oxygen in the air supplied to the cathode electrode 33 is calculated based on the composition ratio of air and the air flow rate detected by the flow rate sensor F3.

  The number of moles of water vapor in the air supplied to the cathode electrode 33 is calculated from the air flow rate detected by the flow rate sensor F3 and the air humidity detected by the dew point sensor D3.

  The number of moles of hydrogen in the exhaust gas discharged from the anode electrode 32 is the number of moles of hydrogen used in power generation of the fuel cell 1 from the number of moles of hydrogen in the fuel gas supplied to the anode electrode 32. Subtract to calculate.

  The number of moles of nitrogen in the fuel gas discharged from the anode electrode 32 is calculated based on the integrated value of the amount of mixed nitrogen converted from the anode / cathode differential pressure of the fuel cell 1 and the opening / closing control of the switching valve 12. To do.

  The number of moles of water vapor in the discharged fuel gas discharged from the anode electrode 32 is calculated from the temperature in the discharged fuel gas detected by the dew point sensor D2 and the flow rate of the circulation pump 5, and the number of moles of water in the discharged fuel gas. Is calculated based on the liquid water flow sensor F2 provided in the drain trap 4.

  The number of moles of nitrogen in the exhaust air discharged from the cathode electrode 33 is set as the number of moles of nitrogen in the air supplied to the cathode electrode 33.

  The number of moles of oxygen in the exhaust air discharged from the cathode electrode 33 is calculated by subtracting the number of moles of oxygen used for power generation of the fuel cell 1 from the number of moles of oxygen supplied to the cathode electrode 33.

  The number of moles of water vapor in the exhaust air discharged from the cathode electrode 33 is calculated based on the humidity in the exhaust air detected by the dew point sensor D4 and the flow rate of the flow sensor F3, and the number of moles of water in the exhaust air is , Based on the liquid water flow sensor F4 provided in the drain trap 7.

  The calculation of the number of moles of each component of the fuel gas supplied to the anode electrode 32, the exhausted fuel gas discharged from the anode electrode 32, the air supplied to the cathode electrode 33, and the discharged air discharged from the cathode electrode 33 is as described above. The method is not limited, and it is sufficient that the number of moles of each component can be calculated.

  The moles of each component of the fuel gas supplied to the anode electrode 32 calculated as described above, the exhausted fuel gas discharged from the anode electrode 32, the air supplied to the cathode electrode 33, and the discharged air discharged from the cathode electrode 33 are calculated. The enthalpy of each component is calculated from the number and the equations (5) and (6).

  For example, the enthalpy of hydrogen in the fuel gas supplied to the anode electrode 32 is calculated by the following equation (7).

Note that N _{H2 — in} is the calculated number of moles of hydrogen in the fuel gas supplied to the anode electrode 32, and T0 is a reference temperature, which is 298.15K here. T1 is the temperature of the fuel gas detected by the temperature sensor T1.

  Further, the enthalpy of hydrogen in the discharged hydrogen discharged from the anode electrode 32 is calculated by the following equation (8).

N _{H2 — out} is the calculated number of moles of hydrogen in the discharged hydrogen discharged from the anode electrode 32, and T3 is the temperature of discharged hydrogen detected by the temperature sensor T3.

  In this embodiment, the enthalpy of each constituent component is calculated in the same manner as in equations (7) and (8), and the total value of the enthalpy of fuel gas supplied to the anode electrode 32 and the enthalpy of air supplied to the cathode electrode 33 is calculated. Is calculated as the total enthalpy of inflow gas. Further, the total value of the enthalpy of the fuel gas discharged from the anode electrode 32 and the enthalpy of the air discharged from the cathode electrode 33 is calculated as the exhaust gas total enthalpy.

  In this embodiment, when the deterioration of the electrolyte membrane 31 is determined by changing the pressure of the anode electrode 32 or the pressure of the cathode electrode 33 every predetermined time, the pressure difference between the anode electrode 32 and the cathode electrode 33 is set to a predetermined pressure. It may be larger than the difference. As a result, when the electrolyte membrane 31 deteriorates, a relatively large amount of air is mixed into the anode electrode 32 or hydrogen is temporarily mixed into the cathode electrode 33. The deterioration of the electrolyte membrane 31 can be determined at an early stage. The predetermined pressure difference is a pressure difference set in advance through experiments or the like. It is desirable to make the pressure of the cathode electrode 33 higher than the pressure of the anode electrode 32. Thereby, when the electrolyte membrane 31 deteriorates, air is mixed from the cathode electrode 33 into the anode electrode 32, and the mixed air circulates through the anode electrode 32 through the hydrogen circulation path 21. Therefore, deterioration determination of the electrolyte membrane 31 can be performed regardless of the positions of the pores opened in the electrolyte membrane 31.

  The effect of 1st Embodiment of this invention is demonstrated.

  In this embodiment, the total enthalpy of inflow gas, which is the total value of the enthalpy of fuel gas and air supplied to the fuel cell 1, and the exhaust gas, which is the total value of the enthalpy of exhaust gas and exhaust air discharged from the fuel cell 1. A first cooling water heat reception amount is calculated based on the total enthalpy, and a second cooling water heat reception amount that is output based on a temperature change of the cooling water that cools the fuel cell 1 is calculated. Then, when the difference between the second cooling water heat reception amount and the first cooling water heat reception amount is larger than a predetermined value, it is determined that the electrolyte membrane 31 has deteriorated. Thereby, the deterioration determination of the electrolyte membrane 31 can be performed in a wide operation region of the fuel cell system. That is, regardless of the load required for the fuel cell system, the deterioration of the electrolyte membrane 31 can be determined, and when the electrolyte membrane 31 is deteriorated, it can be quickly found. In particular, when the load required for the fuel cell system is large, the flow rates of the fuel gas and air supplied to the fuel cell 1 increase, so that the deterioration of the electrolyte membrane 31 can be detected.

  If it is determined that the electrolyte membrane 31 is deteriorated, the pressures of the anode electrode 32 and the cathode electrode 33 are substantially the same, that is, the pressure difference between the anode electrode 32 and the cathode electrode 33 is substantially zero. Or the entry of hydrogen into the cathode electrode 33 can be suppressed, and the progress of the deterioration of the electrolyte membrane 31 can be suppressed. For example, a rapid output reduction or shutdown of the fuel cell system can be prevented. .

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  It can be used for a fuel cell system mounted on an automobile.

It is a schematic block diagram of the fuel cell system of this invention. It is a schematic block diagram of the fuel cell of this invention. It is a flowchart which performs deterioration determination of the electrolyte membrane of this invention. It is a map showing the state of the electrolyte membrane when a fuel cell system is operated for a long time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen cylinder 4, 7 Drain pump 5 Circulation pump 6 Compressor 8 Pressure control valve 9 Radiator 30 Unit cell 31 Electrolyte membrane 32 Anode electrode 33 Cathode electrode 40 Arithmetic device F1, F3, F5 Flow sensor F2, F4 Liquid water flow rate Sensor (Flow sensor)
D1, D2, D3, D4 Dew point sensor T1, T2, T3, T4, T5, T6, T7 Temperature sensor I1 Current sensor V1 Voltage sensor

Claims (6)

A fuel cell that generates electricity by supplying fuel gas and oxidant gas to the electrolyte membrane;
First heat amount equivalent value calculating means for calculating a first heat amount equivalent value of the fuel gas and the oxidant gas supplied to the fuel cell;
A second heat amount equivalent value calculating means for calculating a second heat amount equivalent value of the fuel gas discharged from the fuel cell and the oxidant gas;
A heat amount equivalent value change amount calculating means for calculating a change amount of the heat amount equivalent value in the fuel cell based on the first heat amount equivalent value and the second heat amount equivalent value;
A cooling water heat amount change calculating means for calculating a cooling water heat amount change amount in the fuel cell for cooling the fuel cell;
A fuel cell comprising: an electrolyte membrane deterioration determining unit that determines that the electrolyte membrane has deteriorated when a difference between the amount of change in the heat amount equivalent value and the amount of heat change in the cooling water is equal to or greater than a predetermined value; system. The first heat amount equivalent value calculating means includes:
A flow rate sensor for detecting a flow rate of the fuel gas supplied to the fuel cell;
A humidity detection sensor for detecting the humidity of the fuel gas supplied to the fuel cell;
A temperature sensor for detecting a temperature of the fuel gas supplied to the fuel cell;
A flow rate sensor for detecting a flow rate of the oxidant gas supplied to the fuel cell;
A humidity detection sensor for detecting the humidity of the oxidant gas supplied to the fuel cell;
A temperature sensor for detecting the temperature of the oxidant gas supplied to the fuel cell,
The first heat amount equivalent value is based on the flow rate, the humidity, and the temperature of the fuel gas supplied to the fuel cell, and the flow rate, the humidity, and the temperature of the oxidant gas supplied to the fuel cell. Calculate
The second heat amount equivalent value calculating means includes:
A gas flow rate sensor for detecting a water flow rate in the fuel gas discharged from the fuel cell;
A humidity detection sensor for detecting the humidity of the fuel gas discharged from the fuel cell;
A temperature sensor for detecting the temperature of the fuel gas discharged from the fuel cell;
A flow rate sensor for detecting a water flow rate in the oxidant gas discharged from the fuel cell;
A humidity detection sensor for detecting the humidity of the oxidant gas discharged from the fuel cell;
A temperature sensor for detecting the temperature of the oxidant gas discharged from the fuel cell,
The second heat amount equivalent value includes the water flow rate, the humidity, and the temperature of the fuel gas discharged from the fuel cell, and the water flow rate, the humidity, and the temperature of the oxidant gas discharged from the fuel cell. The fuel cell system according to claim 1, wherein the fuel cell system is calculated based on The calorific value equivalent value change amount calculating means includes:
Generated power calculating means for calculating generated power of the fuel cell;
A heat dissipation amount calculating means for calculating a heat dissipation amount of the fuel cell,
The heat amount equivalent value change amount calculating means calculates a change amount of the heat amount equivalent value based on the first heat amount equivalent value, the second heat amount equivalent value, the generated power, and the heat dissipation amount. The fuel cell system according to claim 1 or 2. Pressure difference control means for controlling the pressure difference between the anode of the fuel cell and the cathode of the fuel cell;
The pressure difference control means makes the pressure difference larger than a predetermined pressure difference when the deterioration judgment of the electrolyte membrane is performed by the electrolyte membrane deterioration judgment means. The fuel cell system described in 1.   5. The fuel cell system according to claim 4, wherein the pressure control unit sets the pressure difference to substantially zero when the electrolyte membrane deterioration determination unit determines that the electrolyte membrane is deteriorated. 6.   6. The fuel cell system according to claim 1, wherein the first heat quantity equivalent value and the second heat quantity equivalent value are enthalpy. 6.

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