KR20100091020A - Fuel cell system and method controlling humidification thereof - Google Patents

Abstract

PURPOSE: A fuel cell system and a controlling method thereof are provided to minimize the structure of a humidifier, and to reduce the power consumption of the system. CONSTITUTION: A fuel cell system(100) comprises the following: a fuel processing device(20) supplying the hydrogen-containing fuel gas; an oxidant gas feeder(30) supplying oxygen-containing oxidizing gas; a fuel cell stack(10) generating an electric chemistry reaction using the fuel gas and the oxidant gas; a cooling device cooling the heat generated from the fuel cell stack; heat recovery device(60) collecting waste heat from high temperature cooling water supplied form the cooling device; and a steam generator(70) generating steam with the waste heat and humidifying the system using the steam.

Description

Fuel cell system and method control method {Fuel Cell System and Method Controlling Humidification Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system using a polymer electrolyte fuel cell stack, and more particularly, to a fuel cell for stably producing electric power by smoothly humidifying fuel gas and / or oxidant gas supplied to a fuel cell stack. It relates to a system and a control method thereof.

The Proton Exchange Membrane Fuel Cell (PEMFC) system uses a polymer membrane with hydrogen ion exchange as an electrolyte and generates an electrochemical reaction using a fuel gas containing hydrogen and an oxidant gas containing oxygen. And generates heat.

The fuel gas and the oxidant gas are each humidified by the humidifier and then supplied to the fuel cell stack. In the humidifier, for example, a bubbler-type humidifier supplies water by passing fuel gas and oxidant gas, respectively, through hot water generated by using a heater. However, bubbler type humidifiers use energy to heat water, thus increasing the power consumption of the fuel cell system. In other words, the efficiency of the fuel cell system is reduced.

In another example, the membrane-type humidifier supplies water to the fuel gas and the oxidant gas by moving a separate gas containing water from each exit side of the fuel gas and the oxidant gas of the fuel cell stack via the water vapor transmission membrane. Membrane humidifiers can reduce energy than bubbler humidifiers because they are humidified using heat and moisture discharged from the fuel cell stack. However, it is difficult for the membrane type humidifier to make the fuel gas and the oxidant gas supplied to the fuel cell stack completely humidified, and the area of the permeable membrane must be increased for the fully humidified state. In other words, in the fuel cell system, the size of the humidifier is increased.

One embodiment of the present invention relates to a fuel cell system and a method of controlling the same, which realizes complete humidification of fuel gas and / or oxidant gas while minimizing the configuration of the humidifier without using additional energy.

One embodiment of the present invention relates to a fuel cell system and a method of controlling the same, which recovers waste heat discharged from a fuel processing device and implements complete humidification of fuel gas and / or oxidant gas.

A fuel cell system according to an embodiment of the present invention includes a fuel processor for supplying a hydrogen-containing fuel gas, an oxidant gas supply device for supplying an oxygen-containing oxidant gas, and an electrochemical reaction using the fuel gas and the oxidant gas. A fuel cell stack that generates a fuel cell stack, a cooling device that cools the heat generated by the fuel cell stack, a heat recovery device that recovers waste heat from the high temperature cooling water supplied from the cooling device and circulated through the fuel cell stack, and has a self pressure. And a steam generator for supplying direct water, generating steam by waste heat of the fuel processor, and supplying and humidifying the steam to at least one of the fuel gas and the oxidant gas supplied to the fuel cell stack.

According to another embodiment of the present invention, a fuel cell system includes: a direct water reducer for adjusting a flow rate of the direct water supplied by adjusting the pressure of the direct water; and installed between the direct pressure reducer and the steam generator to provide steam for humidification. It may further include a proportional control valve for adjusting the amount.

The fuel cell system according to another embodiment of the present invention may further include a pure water generating device for generating pure water by converting the number of water supplied and installed between the direct water reducer and the proportional control valve.

The steam generator is installed in the fuel processor, and the fuel cell system according to another embodiment of the present invention, the fuel gas inlet of the fuel cell stack to inject the steam to the fuel gas supplied to the fuel cell stack. It may further include a spray nozzle installed on the side.

The fuel cell system according to another exemplary embodiment of the present invention may further include a humidifier installed between the oxidant gas supply device and the oxidant gas inlet of the fuel cell stack.

According to another aspect of the present invention, a fuel cell system includes a voltage detector configured to measure a voltage generated by the fuel cell stack over time, and a coolant temperature flowing into the fuel cell stack based on a voltage measured by the voltage detector. It may further include a control device for controlling the.

The fuel cell system according to another embodiment of the present invention may further include a power converter for measuring the generated power by converting the DC power generated in the control device and the fuel cell stack into AC power.

According to another exemplary embodiment of the present invention, a fuel cell system includes a cooling water inlet temperature sensor measuring a cooling water inlet temperature of the fuel cell stack, a fuel gas inlet temperature sensor measuring a fuel gas inlet temperature of the fuel cell stack, and the fuel cell. The oxidant gas inlet temperature sensor for measuring the oxidant gas inlet temperature of the stack may be further included. The proportional control valve may control the amount of steam required for the humidification according to the detection signals of the cooling water inlet temperature sensor, the fuel gas inlet temperature sensor, and the oxidant gas inlet temperature sensor.

The steam generator is installed in the fuel processor, and the fuel cell system according to another embodiment of the present invention has an oxidant gas inlet side of the fuel cell stack to inject the water vapor into the oxidant gas supplied to the fuel cell stack. It may further include a spray nozzle installed in.

In the fuel cell system control method according to an embodiment of the present invention, the power generation step of measuring the generated power generated in the fuel cell stack, the cooling water of the fuel cell stack according to the generated power measured in the generated power measurement step After maintaining the internal temperature of the fuel cell stack and maintaining the internal temperature of the fuel cell stack, the inlet temperature of each of the coolant, fuel gas and oxidant gas supplied to the fuel cell stack is measured, and the measured temperature is measured. If the value is greater than or equal to the set value, the humidification of the fuel cell stack may be stopped / reduced, if the measured temperature value is less than the set value may include a humidification maintenance step of maintaining the humidification by opening the proportional control valve.

The generation power measurement step may include a generation power determination step of determining whether the measured generation power falls within a setting range, and repeating generation power measurement until satisfaction.

The internal temperature maintaining step of the fuel cell stack may include: a cooling water temperature measuring step of measuring a cooling water temperature at a cooling water inlet supplied to the fuel cell stack; and determining whether the cooling water temperature is within a set value range and connecting to a heat exchanger until it is satisfied. It may include a cooling water temperature determination step of repeating the cooling water temperature measurement while adjusting the flow rate of the heat exchange pump.

The humidification holding step is a voltage fluctuation measuring step for measuring a fluctuation range of the voltage generated in the fuel cell stack, and it is determined whether the voltage fluctuation range measured in the voltage fluctuation width measurement step falls within a set value range, and the proportion is satisfied until the proportion is satisfied. The method may further include a voltage fluctuation determining step of stopping the humidification by closing the control valve.

The humidification holding step is a gas temperature measuring step of measuring the temperature of the fuel gas and the oxidant gas supplied to each inlet of the fuel cell stack when the voltage fluctuation range is within the set value range, the fuel gas and the oxidant gas A gas temperature judging step of determining whether the temperature measurement value is smaller than a set value, an opening step of opening the proportional control valve to humidify if the temperature measurement value is less than the set value, and the temperature measured value is the set value. If abnormal, it may include a closing / reducing step of closing or reducing the proportional control valve in order to stop / reduce the humidification.

The humidification maintenance step, after the closing / reducing step, the gas temperature re-measuring step of re-measuring the temperature of the fuel gas and the oxidant gas supplied to the fuel cell stack for a set time, and the temperature of the fuel gas and the oxidant gas And a re-measurement temperature range determination step of determining whether the re-measurement value is within a set value range, and when the temperature re-measurement value is within a set value range, the voltage fluctuation range measuring step may be performed again.

The humidification maintaining step may humidify at least one of the fuel gas and the oxidant gas.

According to an embodiment of the present invention, the fuel gas and / / by generating water vapor in the steam generator using a waste heat discharged from the fuel processing apparatus, and supplying direct water without using a separate water pump, and without additional power consumption Alternatively, since the complete humidification is implemented by spraying on the oxidant gas, it is possible to simplify the configuration of the fuel cell system and reduce the power consumption.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is a configuration diagram schematically showing a fuel cell system according to a first embodiment of the present invention. Referring to FIG. 1, the fuel cell system 100 according to the first embodiment includes a fuel cell including hydrogen in a fuel cell stack 10 and a fuel cell stack 10 generating electrical energy by an electrochemical reaction. The direct current (DC) power generated from the fuel processing device 20 to supply the oxidant gas supply device 30 to supply the oxidant gas containing oxygen to the fuel cell stack 10 and the fuel cell stack 10 may be alternating ( AC) a power converter 40 for converting power and a control device 90 for controlling them.

For example, the fuel cell stack 10 may be formed of a polymer electrolyte fuel cell (PEMFC) that uses a polymer membrane having hydrogen ion exchange characteristics as an electrolyte and generates electricity by causing an electrochemical reaction with hydrogen and oxygen.

The fuel processor 20 reforms the fuel to supply fuel gas containing hydrogen to the fuel gas inlet of the fuel cell stack 10. The oxidant gas supply device 30 may be formed by a compressor or a blower, and supplies air containing oxygen, that is, oxidant gas, to the oxidant gas inlet of the fuel cell stack 10.

The fuel cell system 100 of the first embodiment further includes components for smooth humidification of the fuel gas and / or the oxidant gas supplied to the fuel cell stack 10. For example, the fuel cell system 100 includes a cooling device 50, a heat recovery device 60, a steam generator 70, a direct pressure reducer 61, a proportional control valve 62, and a pure water generator 63. It further includes. In addition, the fuel cell system 100 further includes a humidifier 31 and an oxidant gas inlet temperature sensor 32 installed between the oxidant gas supply device 30 and the oxidant gas inlet of the fuel cell stack 10.

The direct pressure reducer 61 connects a direct supply supply line (not shown) to one side of the pure water generating device 63. The direct water reducer 61 is connected to an external direct water supply line to regulate the flow rate of the direct water by reducing the pressure of direct water supplied from the outside, that is, tap water. As a result, direct water may be used for the fuel cell stack 10. The direct pressure reducer 61 eliminates the need for a separate water supply device, that is, a water pump (not shown) when supplying moisture necessary for humidification of the fuel gas supplied to the fuel cell stack 10, thereby additional power. No consumption is generated. The pure water generating device 63 converts the direct water supplied to the direct pressure reducer 61 into pure water.

In addition, the proportional control valve 62 connects the steam generator 70 to the other side of the pure water generator 63. Proportional control valve 62 is the direct water supplied from the heat recovery device 60 to the steam generator 70, more specifically, by controlling the amount of pure water, thereby adjusting the degree of humidification of the fuel gas, and also the supply of pure water To control or stop the humidification of the fuel gas.

The steam generator 70 is provided so that waste heat can be used inside or on one side of the fuel processor 20, (via the proportional control valve 62 or the proportional control valve 62 and the pure water generator 63). By using the supplied direct water or pure water, the waste heat discharged to the outside is recovered from the fuel processing device 20 to generate steam.The steam generator 70 uses the waste heat heated by the fuel processing device 20 to generate pure water. This makes it unnecessary to use extra energy for generating steam for humidification.

On the other hand, the fuel processing device 20 and the fuel cell stack 10 are connected to the fuel gas supply line 21 and the fuel gas discharge line 22 to supply fuel gas and discharge residual fuel gas between each other. do.

The control valves 23 and 24 are installed in each of the fuel gas supply line 21 and the fuel gas discharge line 22 to control the supply and discharge of fuel gas, respectively. In addition, the fuel gas supply line 21 and the fuel gas discharge line 22 are connected to each other by a bypass line (25). The control valve 26 installed in the bypass pipe 25 may bypass the supply and discharge of fuel gas between the fuel processing device 20 and the fuel cell stack 10.

The fuel gas inlet temperature sensor 27 is provided at the fuel gas inlet of the fuel cell stack 10 connected to the fuel gas supply line 21, and detects the temperature of the supplied fuel gas to control the detection signal 90. To apply.

In addition, the steam generator 70 is connected to the proportional control valve 62 to one side to receive pure water, to recover the waste heat of the fuel processing device 20 to generate steam, and to spray to the other side. It is connected to the nozzle 71 and sprays the generated steam. Since the injection nozzle 71 is installed in the fuel gas supply line 21, water vapor is injected into the fuel gas inlet of the fuel cell stack 10. That is, the steam humidifies the fuel gas.

That is, the pure water generated by the pure water generating device 63 is supplied to the steam generator 70 through the proportional control valve 62, and the waste heat discharged from the fuel processing device 20 is recovered to be steam.

The cooling device 50 supplies cooling water to the fuel cell stack 10 to cool the fuel cell stack 10. For example, the cooling device 50 is a cooling water tank 51 for storing the cooling water, a cooling water pump 52 connected to the cooling water tank 51 to supply the cooling water to the cooling water inlet of the fuel cell stack 10, and the fuel. A cooling water inlet temperature sensor 53 is installed at the cooling water inlet of the battery stack 10 and detects the cooling water temperature at the cooling water inlet.

The cooling water pump 52 is driven in response to the detection of the cooling water inlet temperature sensor 53. The coolant supplied to the coolant inlet of the fuel cell stack 10 by driving the coolant pump 52 cools the fuel cell stack 10, changes to a high temperature state, is discharged to the coolant outlet, and flows into the coolant tank 51 to be recirculated. do.

The high temperature coolant flowing into the coolant tank 51 from the fuel cell stack 10 is cooled while passing through the heat exchanger 55. In addition, the heat exchanger 55 is connected to the heat recovery device 60 via the heat exchange pump 54. The low temperature cooling water of the heat recovery device 60 is circulated and supplied to the heat exchanger 55 by driving the heat exchange pump 54 to recover waste heat of the high temperature cooling water that has cooled the fuel cell stack 10. The heat exchange pump 54 and the heat exchanger 55 are operated in response to the detection of the cooling outlet temperature sensor 56 installed at the cooling outlet of the fuel cell stack 10 to recover the waste heat of the fuel cell stack 10.

On the other hand, the fuel cell system 100 further includes a voltage detector (80). The voltage detector 80 measures the voltage generated by the fuel cell stack 10 over time and applies the detection signal to the control device 90. Therefore, the controller 90 may control the temperature of the coolant at the coolant inlet while maintaining the coolant flowing into the fuel cell stack 10 according to the voltage measured by the voltage detector 80 in the set temperature range.

The voltage detector 80 may determine the initial determination of the humidification of the fuel cell stack 10 as the voltage fluctuation range. In addition, since the power converter 40 starts producing power in the fuel cell stack 10, the power converter 40 continuously measures the generated power to determine whether the generated power falls within a set value range.

The controller 90 receives the detection signal of the voltage detector 80 and controls the fuel cell stack 10 and the power converter 40 connected to the fuel cell stack 10. The oxidant gas inlet detection sensor 32, the cooling water inlet temperature sensor 53, and the fuel gas inlet temperature sensor 27 are connected to the control device 90 to detect respective temperatures to provide a detection signal to the control device 90. Is authorized.

2 is a flowchart illustrating a control method of a fuel cell system according to a first embodiment of the present invention. 1 and 2, the control method of the fuel cell system includes a power generation power measurement step ST10 for measuring power generated in the fuel cell stack 10, and the coolant temperature of the fuel cell stack 10 according to the power generation power. Temperature holding step (hereinafter referred to as "internal temperature holding step") (ST20) for maintaining the fuel cell stack in a set value range and a humidification holding step (ST30) for selectively supplying water vapor to fuel gas and / or oxidant gas. It includes.

The generation power measurement step ST10 is a generation power measurement step ST11 of continuously measuring the generation power in the power converter 40 after starting the production of the power in the fuel cell stack 10, and the measured generation power in the set range. A generation power judging step ST12 for determining whether belonging to the control device 90 is included. The generation power determination step ST12 repeats the generation power measurement step ST11 until the measured generation power falls within the set range. The internal temperature maintenance step ST20 is performed according to the result of the power generation power measurement step ST10.

The internal temperature maintaining step ST20 maintains the coolant temperature of the fuel cell stack 10 in a predetermined value range to maintain the temperature inside the fuel cell stack 10 at a predetermined level. The internal temperature maintenance step ST20 includes a coolant temperature measurement step ST21 for measuring the coolant temperature at the coolant inlet supplied to the fuel cell stack, and a coolant temperature determination step ST22 for determining whether the coolant temperature is within a set value range. Include.

The coolant temperature determination step ST22 repeats the coolant temperature measurement while adjusting the flow rate of the heat exchange pump 54 connected to the heat exchanger 55 until the coolant temperature falls within a set value range. After the temperature inside the fuel cell stack 10 is kept constant, the humidification maintaining step ST30 is performed.

The humidification maintenance step ST30 measures the inlet temperatures of the coolant, the fuel gas, and the oxidant gas supplied to the fuel cell stack 10, and stops the humidification of the fuel cell stack 10 when the measured temperature value is greater than or equal to a set value range. / Decrease, and if the measured temperature value is less than the set value range, the proportional control valve 62 is opened to maintain humidification.

First, in the humidification maintenance step ST30, the voltage fluctuation measuring step ST311 for measuring the fluctuation range of the voltage generated by the fuel cell stack 10 and the voltage fluctuation width measured in the voltage fluctuation measuring step ST311 are within the set value range. A voltage fluctuation determining step (ST312) for determining whether to belong. In addition, the voltage fluctuation determining step ST312 closes the proportional control valve 62 until the measured voltage fluctuation range falls within the set value range, thereby stopping humidification. When the measured voltage fluctuation range is within the set value range, the next step of the voltage fluctuation determining step ST312 is performed in the humidification holding step ST30.

When the measured voltage fluctuation range is within the set value range, the humidification maintaining step ST30 includes a gas temperature measuring step ST321 for measuring the temperature of the fuel gas and the oxidant gas supplied to each inlet of the fuel cell stack 10. The gas temperature determining step ST322 determines whether the temperature measurement values of the fuel gas and the oxidant gas measured in the gas temperature measuring step ST321 are smaller than the set value. In addition, the gas temperature determination step ST322 repeats the gas temperature measurement until the temperature measurement value is smaller than the set value.

When the temperature measurement value is smaller than the set value, the humidification holding step ST30 includes an opening step ST33 for opening the proportional control valve 62. In the opening step ST33, the proportional control valve 62 is opened to supply hot water, and the steam generated from the steam generator 70 is supplied to the fuel cell stack 10 to humidify the fuel gas or the oxidant gas.

When the temperature measurement value is greater than or equal to the set value, the humidification maintenance step ST30 includes a closing / decreasing step ST34 for closing or proportionally decreasing the proportional control valve 62. In the closing / decreasing step ST34, when the temperature measurement value is equal to or greater than the set value, the humidification is stopped or reduced by closing or controlling the flow rate reduction control of the proportional control valve 62.

In addition, the humidification maintenance step (ST30) is a gas temperature re-measuring step (ST35) for re-measuring the temperature of the fuel gas and the oxidant gas supplied to the fuel cell stack 10 for a set time after the closing / reducing step (ST34), And a remeasurement temperature range determination step ST36 for determining whether the temperature remeasurement values of the fuel gas and the oxidant gas fall within a set value range.

When the temperature re-measurement value is within the set value range, the control device 90 performs the voltage fluctuation width measuring step ST31 again. Therefore, in the remeasurement temperature range determination step ST36, after the humidification stop and decrease control, the gas temperature is measured a plurality of times at a specific interval for a set time, and when the temperature remeasurement value satisfies the set value range, the voltage fluctuation range is measured again. (ST31) to determine the first humidification condition.

As described above, the humidification maintenance step ST30 is based on whether the value of the generation voltage fluctuation width continuously measured falls within a set value range on a primary basis, and based on the temperature measurement value of the gas measured at each inlet on a secondary basis. By controlling the proportional control valve 62, the degree of humidification is controlled.

3 is a configuration diagram schematically showing a fuel cell system according to a second embodiment of the present invention. In the second embodiment, descriptions similar to those in the first embodiment will be omitted, and configurations different from those in the first embodiment will be described.

The first embodiment humidifies the oxidant gas through a separate humidifier 31 and at the same time injects water vapor generated by the steam generator 70 into the fuel gas, while the second embodiment does not humidify the fuel gas. In order to humidify the oxidant gas, water vapor generated by the steam generator 70 is injected into the oxidant gas.

To this end, the injection nozzle 71 is installed at the oxidant gas inlet side of the fuel cell stack 10. That is, the injection nozzle 71 is installed between the oxidant gas supply device 30 and the fuel cell stack 10 to inject water vapor into the oxidant gas.

The fuel gas includes some water vapor in the fuel treatment process of the fuel processor 20. In operation of the fuel cell stack 10, the influence on the change in humidification is dominantly determined by the amount of humidification of the oxidant gas.

The second embodiment removes the humidifier 31 on the side of the oxidant gas supply device 30 of the first embodiment, receives pure water from the proportional control valve 62, and converts the water into steam generated by the steam generator 70. Humidify the oxidant gas.

Accordingly, the second embodiment simplifies the overall configuration of the fuel cell system 200 by removing the humidifier 31 compared to the first embodiment, and enables stable operation by adjusting the humidification amount for humidifying the oxidant gas.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

1 is a configuration diagram schematically showing a fuel cell system according to a first embodiment of the present invention.

2 is a flowchart illustrating a control method of a fuel cell system according to a first embodiment of the present invention.

3 is a configuration diagram schematically showing a fuel cell system according to a second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100, 200: fuel cell system 10: fuel cell stack

20: fuel processing device 30: oxidant gas supply device

40: power converter 50: cooling device

60: heat recovery device 70: steam generator

80: voltage detection unit 90: control device

21: fuel gas supply line 22: fuel gas supply line

23, 24, 26: control valve 25: bypass pipe

27: fuel gas inlet temperature sensor 31: humidifier

32: oxidant gas inlet temperature sensor 51: cooling water tank

52: cooling water pump 53: cooling water inlet temperature sensor

54 heat exchange pump 55 heat exchanger

56: cooling water outlet temperature sensor 61: direct pressure reducer

62: proportional control valve 63: pure water generator

Claims (16)

A fuel processing device for supplying a hydrogen containing fuel gas; An oxidant gas supply device for supplying an oxygen-containing oxidant gas; A fuel cell stack that generates an electrochemical reaction using the fuel gas and the oxidant gas; A cooling device for cooling the heat generated in the fuel cell stack; A heat recovery device for recovering waste heat from the high temperature cooling water supplied from the cooling device and circulated through the fuel cell stack; And A steam generator for supplying direct water having a self pressure, generating steam by waste heat of the fuel processor, and humidifying by supplying the steam to at least one of the fuel gas and the oxidant gas supplied to the fuel cell stack. Fuel cell system comprising. According to claim 1, A direct water reducer for controlling the flow rate of the direct water supplied by adjusting the pressure of the direct water And a proportional control valve installed between the direct pressure reducer and the steam generator to adjust an amount of steam required for humidification. The method of claim 2, And a pure water generating device for generating pure water by converting the number of water supplied and installed between the direct water reducer and the proportional control valve. The method of claim 2, The steam generator is installed in the fuel processing device, And a spray nozzle installed at a fuel gas inlet side of the fuel cell stack to inject the water vapor into the fuel gas supplied to the fuel cell stack. 5. The method of claim 4, And a humidifier installed between the oxidant gas supply and the oxidant gas inlet of the fuel cell stack. 5. The method of claim 4, A voltage detector which measures the voltage generated by the fuel cell stack over time, and And a controller for controlling the coolant temperature flowing into the fuel cell stack according to the voltage measured by the voltage detector. The method according to claim 6, And a power converter configured to measure the generated power by converting the DC power generated by the control device and the fuel cell stack into AC power. The method according to claim 6, Cooling water inlet temperature sensor for measuring the cooling water inlet temperature of the fuel cell stack, A fuel gas inlet temperature sensor for measuring a fuel gas inlet temperature of the fuel cell stack, and Further comprising an oxidant gas inlet temperature sensor for measuring the oxidant gas inlet temperature of the fuel cell stack, The proportional control valve, The fuel cell system for controlling the amount of water vapor required for the humidification according to the detection signal of the cooling water inlet temperature sensor, the fuel gas inlet temperature sensor and the oxidant gas inlet temperature sensor. The method of claim 2, The steam generator is installed in the fuel processing device, And an injection nozzle installed at an oxidant gas inlet side of the fuel cell stack to inject the water vapor into the oxidant gas supplied to the fuel cell stack. A generation power measurement step of measuring generation power generated in the fuel cell stack; Maintaining the internal temperature of the fuel cell stack to maintain the cooling water of the fuel cell stack at a predetermined value according to the generated power measured in the power generation power measuring step; And After maintaining the internal temperature of the fuel cell stack, each inlet temperature of the coolant, fuel gas, and oxidant gas supplied to the fuel cell stack is measured, and if the measured temperature is greater than or equal to a set value, the humidification of the fuel cell stack is stopped. And a humidifying maintenance step of reducing the temperature and reducing the measured temperature value by opening the proportional control valve. The method of claim 10, The power generation measurement step, And a generation power judging step of determining whether the measured generation power falls within a set range, and repeating generation power measurement until satisfaction. The method of claim 10, The temperature maintaining step of the fuel cell stack, A cooling water temperature measuring step of measuring the cooling water temperature at the cooling water inlet supplied to the fuel cell stack, and And a coolant temperature determination step of determining whether the coolant temperature is within a set value range and repeating the coolant temperature measurement while adjusting a flow rate of a heat exchange pump connected to a heat exchanger until it is satisfied. The method of claim 10, The humidification maintenance step, A voltage fluctuation measuring step of measuring a fluctuation range of the voltage generated in the fuel cell stack, and And a voltage fluctuation determining step of determining whether the voltage fluctuation range measured in the voltage fluctuation range falls within a set value range and stopping humidification by closing the proportional control valve until the voltage fluctuation range is satisfied. The method of claim 13, The humidification maintenance step, A gas temperature measuring step of measuring a temperature of a fuel gas and an oxidant gas respectively supplied to each inlet of the fuel cell stack when the voltage variation range is within a set value range; A gas temperature determination step of determining whether the temperature measurement values of the fuel gas and the oxidant gas are smaller than a set value; An opening step of opening the proportional control valve to humidify if the temperature measurement value is smaller than the set value, and And closing or reducing the proportional control valve or decreasing the flow rate to stop / reduce humidification when the temperature measurement value is equal to or greater than the set value. 15. The method of claim 14, The humidification maintenance step, A gas temperature re-measuring step of re-measuring the temperature of the fuel gas and the oxidant gas supplied to the fuel cell stack for the set time after the closing / reducing step, and Re-measurement temperature range determination step of determining whether the temperature re-measurement value of the fuel gas and the oxidant gas falls within a set value range, And if the temperature re-measurement value falls within a set value range, performing a voltage fluctuation measurement step again. The method of claim 10, The humidification maintenance step, A fuel cell system control method for humidifying at least one of the fuel gas and the oxidant gas.

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