JP6958078B2 - Fuel cell system - Google Patents

Description

The present invention relates to a fuel cell system.

Conventionally, as a fuel cell system of this type, a system for determining the life of the system has been known. For example, in Patent Document 1, when at least one value of the cumulative power generation time, the cumulative power generation amount, and the cumulative energization time of the fuel cell unit exceeds a predetermined threshold value, it is determined that the life has been reached and the fuel cell unit is stopped. What to do is disclosed. Further, in Patent Document 2, when the cumulative operating time of the fuel cell main body reaches a preset first predetermined value, the fuel cell system is stopped and the cumulative operating number of the fuel cell main body is preset. It is disclosed that the fuel cell system is not started next time when the predetermined value of 2 is reached.

Japanese Unexamined Patent Publication No. 2014-721163 Japanese Unexamined Patent Publication No. 2005-63903

In a system in which the deterioration rate differs depending on the amount of power generated by the fuel cell stack, if the life of the system is determined based on the above-mentioned cumulative power generation time, cumulative energization time, cumulative operation time, and cumulative number of operations, a large error will occur depending on the operation method. .. On the other hand, if the life of the system is determined by the cumulative power generation amount, the error caused by the change in the power generation amount can be reduced, but if the output voltage of the fuel cell stack changes with the aging of the system, the same power generation amount is generated. Since the output current required for obtaining the power changes, and the flow rate of the raw material fuel gas and the flow rate of the reforming water also change, it is difficult to accurately determine the life when the deterioration rate differs depending on these flow rates. ..

The main purpose of the fuel cell system of the present invention is to improve the accuracy of life determination.

The fuel cell system of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The fuel cell system of the present invention
A fuel cell system including a fuel cell capable of generating electricity based on a reforming gas and an oxidant gas.
A reforming unit that reforms the raw fuel gas into the reformed gas using reformed water and supplies it to the fuel cell.
A raw material fuel gas supply device that supplies the raw material fuel gas to the reforming unit, and
A reforming water supply device that supplies the reforming water to the reforming unit,
A control device that sets a current command for the fuel cell so that the fuel cell generates electricity with the required power, and controls the raw material fuel gas supply device and the reformed water supply device based on the set current command.
With
The control device integrates the output current of the fuel cell, and when the integrated value of the output current reaches a threshold value, determines that the life is reached.
The gist is that.

In the fuel cell system of the present invention, a fuel cell current command is set so that the fuel cell generates electricity with the required power, and the raw fuel gas supply device and the reformed water supply device are controlled based on the set current command. In, the output current of the fuel cell is integrated, and when the integrated value of the output current reaches the threshold value, it is determined that the life is reached. As a result, in a system in which the deterioration rate changes depending on the flow rate of the raw material fuel gas and the flow rate of the reforming water, the life can be appropriately determined. Further, even if the output current required for the fuel cell to generate power with the required power changes due to the aged use of the fuel cell system, the change in the current can be reflected in the life determination, so that the accuracy of the life determination is improved. be able to. When it is determined that the fuel cell system has reached the end of its life, the operation of the system can be stopped or the system can be prevented from being started next time.

In such a fuel cell system of the present invention, the control device may convert the flow rate of the raw material fuel gas supplied by the raw material fuel gas supply device at the time of system startup into the output current and integrate the output current. good. By determining the life of the fuel cell system in consideration of the flow rate of the raw fuel gas supplied when the system is started, the accuracy of the life determination can be further improved.

Further, in the fuel cell system of the present invention, the control device converts the flow rate of the raw fuel gas supplied by the raw material fuel gas supply device into the output current and integrates the output current when the system is stopped. May be good. By determining the life of the fuel cell system in consideration of the flow rate of the raw fuel gas supplied when the system is stopped, the accuracy of the life determination can be further improved.

Further, the fuel cell system of the present invention may be provided with a desulfurizer provided in the raw fuel gas supply flow path of the raw material fuel gas supply device to remove sulfur contained in the raw material fuel gas. When the desulfurizer has a rate-determining life, the life of the fuel cell system can be appropriately determined.

Further, in the fuel cell system of the present invention, a water tank for storing the reformed water supplied to the reforming unit by the reforming water supply device, a combustion unit for burning the reformed gas that has passed through the fuel cell, and a combustion unit. A condensed water flow path for supplying condensed water generated by cooling the combustion exhaust gas generated by combustion of the reforming gas to the water tank, and a water purifier provided in the condensed water flow path for purifying the condensed water. And may be provided. When the life of the water purifier is the rate-determining factor, the life of the fuel cell system can be appropriately determined.

It is a block diagram which shows the outline of the structure of the fuel cell system 10 of this embodiment. It is a flowchart which shows an example of the life determination routine. It is a flowchart which shows an example of a stack current integration process. It is explanatory drawing which shows the relationship between the gas flow rate Qg and the conversion value of a stack current I.

A mode for carrying out the present invention will be described.

FIG. 1 is a configuration diagram showing an outline of the configuration of the fuel cell system 10 of the present embodiment. As shown in FIG. 1, the fuel cell system 10 of the present embodiment includes a power generation unit 20 having a fuel cell stack 36 that generates power by being supplied with a fuel gas containing hydrogen and an oxidizing agent gas (air) containing oxygen. The hot water supply unit 100 has a hot water storage tank 101 that recovers and supplies hot water generated by the power generation of the power generation unit 20, and a control device 80 that controls the entire system.

The power generation unit 20 has a vaporizer 32 that evaporates reformed water to generate water vapor and preheats a raw material fuel gas (for example, natural gas or LP gas), and a fuel gas containing hydrogen from the raw material fuel gas and water vapor (modified). A power generation module 30 including a reformer 33 for generating (quality gas), a fuel cell stack 36 for generating power by fuel gas and air, a raw fuel gas supply device 40 for supplying raw fuel gas to the vaporizer 32, and a raw fuel gas supply device 40. The air supply device 50 that supplies air to the fuel cell stack 36, the reforming water supply device 55 that supplies the reforming water in the reforming water tank 57 to the vaporizer 32, and the exhaust heat generated by the power generation module 30 are recovered. The exhaust heat recovery device 60 is provided.

The housing 22 is provided with an intake port 22a and an exhaust port 22b. A ventilation fan 24 for taking in outside air and ventilating the inside of the housing 22 is provided near the intake port 22a, and a combustible gas sensor 93 for detecting leakage of combustible gas is provided near the exhaust port 22b. There is.

The reformer 33 is configured by supporting a reforming catalyst (for example, a Ru or Ni-based catalyst) on a carrier such as ceramic, and steam reforms a mixed gas of raw fuel gas and steam supplied from the vaporizer 32. It reforms into fuel gas (reforming gas) by a quality reaction.

The vaporizer 32, the reformer 33, and the fuel cell stack 36 constituting the power generation module 30 are housed in a box-shaped module case 31 formed of a heat insulating material. The module case 31 is provided with a combustion unit 34 for starting the fuel cell stack 36, generating steam in the vaporizer 32, and supplying heat required for the steam reforming reaction in the reformer 33. Fuel off gas (anode off gas) and oxidant off gas (cathode off gas) that have passed through the fuel cell stack 36 are supplied to the combustion unit 34, and the mixed gas is ignited by the ignition heater 35 and burned to burn the fuel cell. The stack 36, the vaporizer 32, and the reformer 33 are heated. The combustion exhaust gas generated by the combustion of the fuel off gas and the oxidant off gas is supplied to the heat exchanger 62 via the combustion catalyst 37. The combustion catalyst 37 is an oxidation catalyst that reburns the fuel gas left unburned in the combustion unit 34 by the catalyst.

The exhaust heat recovery device 60 has a circulation pipe 61 that connects the heat exchanger 62 and the hot water storage tank 101 that stores the hot water storage water to form a circulation path for the hot water storage water. A circulation pump 63 is provided in the circulation pipe 61. By driving the circulation pump 63 to circulate the stored hot water, the heat exchanger 62 heats the stored hot water by exchanging heat with the combustion exhaust gas. The heated hot water is stored in the hot water storage tank 101. The heat exchanger 62 is connected to the reforming water tank 57 via the condensed water supply pipe 66 and is connected to the outside air via the exhaust gas discharge pipe 67. The combustion exhaust gas supplied to the heat exchanger 62 is cooled by heat exchange with the hot water to condense the water vapor component, and is recovered in the reformed water tank 57 via the condensed water supply pipe 66. A water purifier 68 is provided in the condensed water supply pipe 66, and the condensed water of the combustion exhaust gas is supplied to the reformed water tank 57 after impurities are removed by the water purifier 68. Further, the remaining exhaust gas is discharged to the outside air through the exhaust gas discharge pipe 67.

The raw fuel gas supply device 40 has a raw fuel gas supply pipe 41 that connects the gas supply source 1 and the vaporizer 32. The raw fuel gas supply pipe 41 is provided with raw fuel gas supply valves 42, 43 (double valves), an orifice 44, a raw fuel gas pump 45, and a desulfurizer 46 in this order from the gas supply source 1 side. By driving the raw material fuel gas pump 45 with the gas supply valves 42 and 43 opened, the raw material fuel gas from the gas supply source 1 is passed through the desulfurizer 46 and supplied to the vaporizer 32. The raw fuel gas supplied to the vaporizer 32 is supplied to the reformer 33 via the vaporizer 32 and reformed into the fuel gas. The desulfurization device 46 removes the sulfur content contained in the raw material fuel gas, and for example, a room temperature desulfurization method for removing the sulfur compound by adsorbing it on an adsorbent such as zeolite can be adopted. Further, a pressure sensor 47 for detecting the pressure of the raw material gas in the raw material gas supply pipe 41 is provided between the raw material gas supply valve 43 of the raw material gas supply pipe 41 and the orifice 44, and the orifice 44 and the orifice 44 are provided. A flow sensor 48 for detecting the flow rate (gas flow rate Qg) per unit time of the raw fuel gas flowing through the raw material gas supply pipe 41 is provided between the raw material gas pump 45 and the raw material gas pump 45.

The air supply device 50 has an air supply pipe 51 that connects the filter 52 that communicates with the outside air and the fuel cell stack 36. The air supply pipe 51 is provided with an air blower 53, and by driving the air blower 53, air sucked through the filter 52 is supplied to the fuel cell stack 36. Further, the air supply pipe 51 is provided with a flow rate sensor 54 on the downstream side of the air blower 53 to detect the flow rate (air flow rate Qa) of the air flowing through the air supply pipe 51 per unit time.

The reformed water supply device 55 has a reformed water supply pipe 56 that connects the reformed water tank 57 for storing the reformed water and the vaporizer 32. The reforming water supply pipe 56 is provided with a reforming water pump 58, and by driving the reforming pump 58, the reformed water in the reforming water tank 57 is supplied to the vaporizer 32. The reformed water supplied to the vaporizer 32 is converted into steam by the vaporizer 32 and used for the steam reforming reaction in the reformer 33.

The fuel cell stack 36 includes a solid oxide fuel cell having a solid electrolyte composed of an oxygen ion conductor, an anode provided on one surface of the solid electrolyte, and a cathode provided on the other surface of the solid electrolyte. It is configured as a laminated structure, and generates electricity by an electrochemical reaction between hydrogen in the fuel gas supplied to the anode and oxygen in the air supplied to the cathode. A power line 3 from the commercial power source 2 to the load 4 is connected to the output terminal of the fuel cell stack 36 via a power conditioner 71 including a DC / DC converter and an inverter, and DC power from the fuel cell stack 36. Is added to the AC power from the commercial power source 2 through voltage conversion and DC / AC conversion by the power conditioner 71, and is supplied to the load 4. A current sensor 91 for detecting the output current (stack current I) of the fuel cell stack 36 is provided in the power line connected to the output terminal of the fuel cell stack 36, and between the output terminals of the fuel cell stack 36, A voltage sensor 92 for detecting the voltage between terminals (stack voltage V) of the fuel cell stack 36 is provided.

Further, the power supply board 72 is connected to the power line branched from the power conditioner 71. The power supply board 72 includes a raw fuel gas supply valve 42, 43, a raw fuel gas pump 45, an air blower 53, a reforming water pump 58, a circulation pump 63, a pressure sensor 47, a flow rate sensor 48, 54, a display panel 90, and a current sensor 91. It functions as a DC power source that supplies DC power to auxiliary machinery such as the voltage sensor 92 and the combustible gas sensor 93.

The control device 80 is configured as a microprocessor centered on the CPU 81, and in addition to the CPU 81, a ROM 82 for storing a processing program, a RAM 83 for temporarily storing data, and a flash memory as a rewritable non-volatile memory. It includes 84 and an input / output port (not shown). Various detection signals from the pressure sensor 47, the flow rate sensors 48, 54, the current sensor 91, the voltage sensor 92, the combustible gas sensor 93, and the like are input to the control device 80 via the input port. Further, from the control device 80, a drive signal to the fan motor of the ventilation fan 24, a drive signal to the solenoids of the raw fuel gas supply valves 42 and 43, a drive signal to the pump motor of the raw fuel gas pump 45, and a blower motor of the air blower 53. Drive signal to the pump motor of the reforming water pump 58, drive signal to the pump motor of the circulation pump 63, control signal to the inverter and DC / DC converter of the power conditioner 71, to the ignition heater 35. A drive signal, a display signal to the display panel 90 displaying various information, and the like are output via the output port.

Next, the operation of the fuel cell system 10 thus configured, that is, each operation of system start, power generation, and system stop will be described.

To start the system, the corresponding auxiliary machinery is sequentially controlled, and the fuel component is adsorbed on the desulfurizer 46 to suppress the air-fuel ratio deviation of the mixed gas, the fuel adsorption process, the purge process of the combustion unit 34, and the off gas in the combustion unit 34. It is carried out by sequentially executing the ignition treatment and the steam reforming treatment.

Power generation is performed by controlling the raw material fuel gas supply device 40, the air supply device 50, and the reforming water supply device 55 so as to generate power with the required power required for the system. Specifically, the CPU 81 of the control device 80 first receives a current command I * which is an output current to be output by the fuel cell stack 36 by feedback control based on the deviation between the required power and the generated power of the fuel cell stack 36. To set. The generated power of the fuel cell stack 36 can be calculated by multiplying the stack current I detected by the current sensor 91 and the stack voltage V detected by the voltage sensor 92. Subsequently, the target gas flow rate Qg *, the target air flow rate Qa *, and the target water amount Qw * are set based on the set current command I *. Then, the raw fuel gas pump 45 is controlled so that the raw material fuel gas is supplied from the raw material fuel gas supply device 40 at the target gas flow rate Qg * (raw material fuel gas supply control), and air is aired from the air supply device 50 at the target air flow rate Qa *. (Air supply control), and the reforming water pump 58 is controlled so that the reforming water supply device 55 supplies the reforming water at the target water amount Qw * (reforming water supply control). ). In the raw fuel gas supply control, the duty ratio is set by feedback control based on the deviation between the target gas flow rate Qg * and the gas flow rate Qg detected by the flow rate sensor 48, and the pump of the raw fuel gas pump 45 is pumped based on the set duty ratio. It is done by controlling the motor. In the air supply control, the duty ratio is set by feedback control based on the deviation between the target air flow rate Qa * and the air flow rate Qa detected by the flow rate sensor 54, and the blower motor of the air blower 53 is controlled based on the set duty ratio. It is done by. The reformed water supply control is performed by setting a duty ratio based on the target water amount Qw * and controlling the pump motor of the reformed water pump 58 based on the set duty ratio.

The system is stopped by a gradual reduction process of the raw material fuel gas that gradually reduces the flow rate of the raw material fuel gas (gas flow rate Qg), and by supplying air to the fuel cell stack 36 to cool it until the temperature of the fuel cell stack 36 falls below a predetermined temperature. It is performed by executing the cooling process to be performed.

Next, the operation of determining the life of the fuel cell system 10 will be described. FIG. 2 is a flowchart showing an example of a life determination routine executed by the CPU 81 of the control device 80. This routine is repeatedly executed at predetermined time intervals.

When the life determination routine is executed, the CPU 81 of the control device 80 first performs a stack current integration process for integrating the stack current I (S100). The stack current integration process can be performed by the stack current integration process illustrated in FIG. In the stack current integration process of FIG. 3, the CPU 81 first determines whether or not power generation is in progress (S200), whether or not the system is starting up, and whether or not the system is stopped (S210). .. If it is determined that the system is not generating power, the system is starting up, or the system is stopped, the stack current integration process is terminated as it is. On the other hand, when it is determined that power is being generated, the stack current I from the current sensor 91 is input (S220), the input stack current I is integrated to calculate the stack current cumulative value ΣI, and the stack current cumulative value ΣI is stored in the flash memory 84. (S230), the stack current integration process is completed. When it is determined that either the system is starting or the system is stopped, the gas flow rate Q from the flow rate sensor 47 is input (S240), and the input gas flow rate Qg is converted into the stack current I (S250). Here, when the gas flow rate Qg is converted to the stack current I, the relationship between the gas flow rate Qg and the conversion value of the stack current I is obtained in advance and stored in the ROM 82 as a conversion map, and the gas flow rate Qg is given. , The conversion value of the corresponding stack current I was derived from the map. FIG. 4 shows a conversion map. Although the conversion of the gas flow rate Qg to the stack current I is performed using the conversion map of FIG. 4, it may be performed by calculation using the conversion coefficient. When converted to the stack current I, the converted stack current I is integrated to calculate the cumulative stack current value ΣI, which is stored in the flash memory 84 (S260), and the stack current integration process is completed.

When the stack current cumulative value ΣI is calculated in this way, the CPU 81 determines whether or not the calculated stack current cumulative value ΣI is equal to or greater than the threshold value Iref (S110). Here, the threshold value Iref is a threshold value for determining the life of the fuel cell system 10, and is predetermined based on the specifications of the fuel cell system 10. The threshold Iref can be determined based on the specifications of the desulfurizer 46, for example, when the desulfurizer 46 is the rate-determining of the life of the fuel cell system 10, and the water purifier 68 is the rate-determining of the life of the fuel cell system 10. In this case, it can be determined based on the specifications of the water purifier 68. If it is determined that the cumulative stack current ΣI is less than the threshold value Iref, it is determined that the life of the fuel cell system 10 has not reached, and the life determination routine is terminated. On the other hand, if it is determined that the cumulative stack current value ΣI is equal to or higher than the threshold value Iref, the fuel cell system 10 is stopped (S120), the life of the fuel cell system 10 has expired, and the system needs to be replaced or maintained. Is displayed on the display panel 90 (S130), and the life determination routine is terminated.

In the fuel cell system 10 of the embodiment described above, the current command I * of the fuel cell stack 36 is set so that the fuel cell stack 36 generates power by the required power, and the raw fuel gas supply device is based on the set current command I *. In the device that controls 40 and the reforming water supply device 55, the stack current I is integrated to calculate the stack current cumulative value ΣI, and when the stack current cumulative value ΣI becomes equal to or greater than the threshold fuel, the system has reached the end of its life. Judge and shut down the system. As a result, in a system in which the deterioration rate changes depending on the flow rate of the raw material fuel gas and the flow rate of the reforming water, the life can be appropriately determined. Further, even if the stack current required for the fuel cell stack 36 to generate power with the required power changes due to the aged use of the fuel cell system 10, the change in the current can be reflected in the life determination, and the accuracy of the life determination can be determined. Can be enhanced.

Further, in the fuel cell system 10 of the embodiment, the flow rate of the raw fuel gas (gas flow rate Qg) supplied while the system is started or stopped is converted into the stack current I, and the converted stack current I is integrated to integrate the stack current. Since the cumulative value ΣI is calculated, the accuracy of the life determination can be further improved.

In the above-described embodiment, the output current (stack current I) of the fuel cell stack 36 detected by the current sensor 91 is integrated to calculate the stack current cumulative value ΣI, and the system is based on the calculated stack current integrated value ΣI. Although the life is determined, the stack current cumulative value ΣI may be calculated by integrating the current command I * of the fuel cell stack 36.

In the above-described embodiment, the operation during system startup and system shutdown is also taken into consideration in the life determination of the fuel cell system 10, but the operation during system startup and / or system shutdown is considered. It may not be put in.

In the above-described embodiment, the system is stopped when the cumulative stack current ΣI is equal to or higher than the threshold value Iref. However, the operation of the system is continued, and the system is not started next time after the system is stopped. May be good.

In the above-described embodiment, the solid oxide fuel cell is used as the fuel cell of the fuel cell system 10, but any type of fuel cell such as a solid polymer fuel cell may be used. The above-mentioned method of converting the flow rate of the raw material fuel gas supplied while the system is starting up or stopping the system into the stacking current I to calculate the cumulative stacking current value ΣI and determining the life of the system is, for example, a solid polymer. It is particularly effective in a fuel cell system in which the system is frequently started and stopped, such as an electric vehicle equipped with a fuel cell.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the fuel cell stack 36 corresponds to the fuel cell, the reformer 33 corresponds to the reformer, the raw fuel gas supply device 40 corresponds to the raw fuel gas supply device, and the reformed water supply device 55 It corresponds to the reformed water supply device, and the control device 80 corresponds to the control device. Further, the desulfurizer 46 corresponds to a desulfurizer. Further, the reformed water tank 57 corresponds to a water tank, the combustion unit 34 corresponds to a combustion unit, the condensed water pipe 66 corresponds to a condensed water flow path, and the water purifier 68 corresponds to a water purifier.

Regarding the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for the embodiment to solve the problem is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the embodiment is the invention described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above using the embodiments, the present invention is not limited to these embodiments, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of fuel cell systems and the like.

1 gas supply source, 2 commercial power supply, 3 power line, 4 load, 10 fuel cell system, 20 power generation unit, 22 housing, 22a intake port, 22b exhaust port, 24 ventilation fan, 30 power generation module, 31 module case, 32 Vaporizer, 33 reformer, 34 combustion part, 35 ignition heater, 36 fuel cell stack, 37 combustion catalyst, 40 raw fuel gas supply device, 41 raw fuel gas supply pipe, 42, 43 raw fuel gas supply valve, 44 orifice , 45 Raw fuel gas pump, 46 desulfurizer, 47 pressure sensor, 48 flow sensor, 50 air supply device, 51 air supply pipe, 52 filter, 53 air blower, 54 flow sensor, 55 reformed water supply device, 56 reformed water supply Pipe, 57 reformed water tank, 58 reformed water pump, 59 flow sensor, 60 exhaust heat recovery device, 61 circulation pipe, 62 heat exchanger, 63 circulation pump, 66 condensed water supply pipe, 67 exhaust gas discharge pipe, 68 Water Purifier, 71 Power Conditioner, 72 Power Board, 80 Controller, 81 CPU, 82 ROM, 83 RAM, 84 Flash Memory, 85 Timer, 90 Display Panel, 91 Current Sensor, 92 Voltage Sensor, 93 Combustible Gas Sensor, 100 Hot water supply unit, 101 hot water storage tank.

Claims (4)

A fuel cell system including a fuel cell capable of generating electricity based on a reforming gas and an oxidant gas.
A reforming unit that reforms the raw fuel gas into the reformed gas using reformed water and supplies it to the fuel cell.
A raw material fuel gas supply device that supplies the raw material fuel gas to the reforming unit, and
A reforming water supply device that supplies the reforming water to the reforming unit,
The current command of the fuel cell is set so that the fuel cell generates electricity with the required power, the target flow rate of the raw fuel gas is set based on the set current command, the raw fuel gas supply device is controlled, and the modification is performed. a control device for controlling the quality water supply equipment,
A current sensor that detects the output current of the fuel cell and
With
The control device integrates the output current of the fuel cell detected by the current sensor when power is being generated, and is predetermined as the relationship between the flow rate of raw fuel gas and the output current when the system is running. Using the above relationship, the flow rate of the raw fuel gas supplied by the raw material fuel gas supply device during the system startup is converted into the output current, the output current is integrated, and the integrated value of the output current reaches the threshold value. Then, it is judged that it has reached the end of its life.
Fuel cell system. A fuel cell system including a fuel cell capable of generating electricity based on a reforming gas and an oxidant gas.
A reforming unit that reforms the raw fuel gas into the reformed gas using reformed water and supplies it to the fuel cell.
A raw material fuel gas supply device that supplies the raw material fuel gas to the reforming unit, and
A reforming water supply device that supplies the reforming water to the reforming unit,
The current command of the fuel cell is set so that the fuel cell generates electricity with the required power, the target flow rate of the raw fuel gas is set based on the set current command, the raw fuel gas supply device is controlled, and the modification is performed. A control device that controls the quality water supply device and
A current sensor that detects the output current of the fuel cell and
With
The control device integrates the output current of the fuel cell detected by the current sensor when power is being generated, and is predetermined as the relationship between the flow rate of raw fuel gas and the output current when the system is stopped. Using the above relationship, the flow rate of the raw fuel gas supplied by the raw material fuel gas supply device is converted into the output current and the output current is integrated while the system is stopped, and the integrated value of the output current reaches the threshold value. Then, it is judged that it has reached the end of its life.
Fuel cell system. The fuel cell system according to claim 1 or 2.
A desulfurizer provided in the raw material gas supply flow path of the raw material fuel gas supply device and for removing sulfur contained in the raw material fuel gas is provided.
Fuel cell system. The fuel cell system according to any one of claims 1 to 3.
A water tank for storing the reformed water supplied to the reforming unit by the reforming water supply device, and
A combustion unit that burns the reformed gas that has passed through the fuel cell,
A condensed water flow path that supplies condensed water generated by cooling the combustion exhaust gas generated by combustion of the reformed gas to the water tank, and
A water purifier provided in the condensed water flow path for purifying the condensed water,
Fuel cell system with.

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