KR101134702B1 - Exhaust Gas Recircling Apparatus For Fuel Cell System and Control Method - Google Patents

Abstract

The present invention relates to an apparatus for recirculating exhaust gas of a fuel cell and a method of controlling the same, by using high temperature and high humidity air discharged from a stack outlet of a fuel cell by returning it to an input line of a stack to optimize the state of the stack. The present invention relates to an apparatus for recirculating exhaust gas of a fuel cell and a method of controlling the same, the air supply for introducing external air of a vehicle through an air cleaner, and the dry air introduced by the air supply. Humidity air discharged from the outlet of the stack while supplying an air volume control unit for controlling the state and the amount of air, a stack into which the air controlled by the air volume control unit is introduced, the hydrogen gas supplied from the hydrogen supply unit for supplying hydrogen gas to the stack Humidification unit for humidifying the hydrogen gas using, the hydrogen gas supplied to the stack through the humidifying unit A hydrogen recirculation pump for returning back to the inlet side of the stack, a sensing unit for sensing a temperature and humidity state of the stack outlet air, and receiving a state value of the air detected by the sensing unit to determine the air velocity and air volume of the air volume adjusting unit. It provides a discharge gas recirculation device of the fuel cell, characterized in that it comprises a control unit for controlling, the step of introducing air outside the vehicle by the air supply as a method for controlling the exhaust gas recirculation device of the fuel cell Adjusting the state of the introduced air, humidifying the hydrogen gas introduced from the hydrogen supply unit, the exhaust gas of the fuel cell, characterized in that it comprises a step of supplying the controlled air and hydrogen gas to the stack Provides a recirculation control method.

Fuel Cell, Stack, Ejector, Orifice

Description

Exhaust Gas Recircling Apparatus For Fuel Cell System and Control Method}

1 is a block diagram showing a conventional fuel cell recycling apparatus.

2 is a view showing the configuration of the exhaust gas recirculation apparatus of a fuel cell according to the present invention.

3 is a view showing an embodiment according to the configuration of the exhaust gas recirculation apparatus of the fuel cell according to the present invention.

4 is a flowchart illustrating a method for controlling exhaust gas recirculation of a fuel cell according to the present invention.

5 and 6 is a flow chart illustrating the step of adjusting the state of the air according to the exhaust gas recirculation control method of the fuel cell according to the present invention.

* Description of the symbols for the main parts of the drawings *

10: air supply 20: air volume control unit

22: mixer 24: air recirculation fan

26: ejector 18: variable part

30: stack 50: humidifier

60: hydrogen recycle pump 70: detector

80: control unit

The present invention relates to an apparatus for recirculating exhaust gas of a fuel cell and a method of controlling the same, by using high temperature and high humidity air discharged from a stack outlet of a fuel cell by returning it to an input line of a stack to optimize the state of the stack. An exhaust gas recirculation apparatus of a fuel cell that can be operated in a state and a control method thereof.

In general, the reserves of fossil fuels using underground resources such as coal, oil, and natural gas are limited, and in the reality that oil prices are soaring due to the increased demand for fossil fuels due to explosive population growth, it is possible to replace the fossil fuels described above. The development of alternative energy is an urgent reality.

Fuel cells using hydrogen gas and air have been developed to replace these limited fossil fuels.

The fuel cell is a device that converts chemical energy of fuel and oxidant into electrical energy by electrochemical reaction, which is more energy efficient than conventional internal combustion engines, and is generally transported from a very small fuel source. The range of applications ranges from alternative power sources for vehicles, to large-scale power generation systems.

In the fuel cell, there is a cell that generates electricity. In an actual fuel cell for a vehicle, a plurality of cells are stacked and used as a large amount of electric energy in order to obtain a higher potential. Stacked a plurality of is called a stack (Stack).

The fuel cell has a high current density (current flowing through a cross section of a unit width) and a high output density (output per unit volume) and a short start-up time, which uses a solid electrolyte and does not require corrosion and electrolyte control. As an environmentally friendly source of emissions, active research is underway in the global automotive industry.

Currently, the most popular fuel cell fuel cell is a polymer electrolyte fuel cell. In the polymer electrolyte fuel cell, a supply line of air and hydrogen gas is humidified, and thus the membrane (membrane) of the fuel cell has high humidity. The condition is high enough to show sufficient Proton Conductivity.

1 is a diagram illustrating a conventional fuel cell recirculation apparatus. Referring to the accompanying drawings, an air supply 3, a cathode humidifier 4 in which air introduced by the air supply 3 is humidified, and hydrogen An anode humidifier (5) for humidifying a gas, a stack (30) into which humidified air and hydrogen are introduced from the cathode humidifier (4) and an anode humidifier (5), and a condenser for condensing air discharged from the stack ( 6), a water tank (7) for supplying water to the cathode humidifier (4) and the anode humidifier (5), a condensate pump (8) for recovering the water recovered in the condenser (6) to the water tank (6) It is configured to include.

The conventional fuel cell recirculation apparatus configured as described above includes a water tank (7) and a condensate pump (8) in the winter season when the external weather falls below zero, and thus the pipe line through which water passes freezes. The operation itself is not possible, and the bulky and complicated size of the device has created a problem that is difficult to maintain.

The present invention has been made to solve the above problems, to prevent freezing problems caused when operating the fuel cell in the cold winter, and to operate the stack by adjusting the state of the air recycled to the stack to the optimal state The purpose is.

The present invention for achieving the above object, the air supply for introducing the outside air of the vehicle through the air cleaner, the air amount adjusting unit for controlling the state and the air volume of the dry air introduced by the air supply, in the air amount adjusting unit A humidified part for supplying hydrogen gas supplied from a hydrogen supply part supplying hydrogen gas to the stack, but a humidifying part for humidifying hydrogen gas using humidifying air discharged from the outlet of the stack, and a stack through the humidifying part. Hydrogen recycle pump for returning the supplied hydrogen gas back to the inlet side of the stack, a sensing unit for detecting the temperature and humidity of the stack outlet air, the air volume control unit receives the air state value detected by the sensing unit Fuel field, characterized in that it comprises a control unit for controlling the speed and amount of air Is that of providing an exhaust gas recirculation device characterized.

Introducing air outside the vehicle by an air supply in a method for controlling the exhaust gas recirculation device of the fuel cell, Adjusting the state of the introduced air, Humidifying the hydrogen gas introduced from the hydrogen supply unit, It is characterized by providing an exhaust gas recirculation control method of a fuel cell, characterized in that it comprises a step of supplying a condition-conditioned air and hydrogen gas to the stack.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a view showing the configuration of the exhaust gas recirculation apparatus of the fuel cell according to the present invention, Figure 4 is a flow chart illustrating a method for controlling the exhaust gas recirculation of the fuel cell according to the present invention.

Referring to the accompanying drawings, the present invention provides an air supply unit 10 for introducing external air of a vehicle through an air cleaner, and an air amount adjusting unit 20 for controlling the state and amount of air flowing into the air supplied by the air supply unit 10. ), The stack 30 into which the air controlled by the air amount adjusting unit 20 is introduced, the hydrogen gas supplied from the hydrogen supply unit 40 supplying hydrogen gas to the stack 30, but the stack 30 of the stack 30 Humidification unit 50 for humidifying hydrogen gas using the humidifying air discharged from the outlet, hydrogen recycling to return the hydrogen gas supplied to the stack 30 through the humidifying unit 50 back to the inlet side of the stack 30 Pump 60, the sensing unit 70 for sensing the temperature and humidity of the outlet air outlet 30, the state value of the air detected by the sensing unit 70 receives the input of the air volume control unit 20 The control unit 80 for adjusting the speed and amount of air It provides an exhaust gas recirculation device of a fuel cell, characterized in that also the configuration.

The air amount adjusting unit 20 returns a mixer 22 installed on a line in which the air supplier 10 and the stack 30 are connected, and the air recovered from the outlet of the stack 30 to the mixer 22. It is preferably configured to include an air recirculation fan 24.

Alternatively, the air amount adjusting unit 20 may include an ejector 26 installed on a line in which the air supply 10 and the stack 30 are connected, and the air recovered from the outlet of the stack 30 to the ejector 26. It is preferable to include a variable portion 28 to return.

The variable portion 28 preferably uses a variable orifice.

The humidifier 50 uses a gas to gas humidifier to humidify the hydrogen gas using air in a humidified state discharged from the hydrogen supply unit 40 from the stack 30. It is desirable.

The gas-to-gas humidifier is formed with two tubes having different diameters, the hydrogen gas passes through the inner tube and is inserted into the outer circumferential surface of the inner tube through which the hydrogen gas passes and stacked on an outer tube integrally formed with the inner tube. Humidified air discharged from 30 is passed through to humidify the hydrogen gas.

The sensing unit 70 preferably uses a sensor for detecting a temperature and humidity state of the air discharged from the stack 30.

Introducing air from the outside of the vehicle by the air supply in a method for controlling the exhaust gas recirculation device of the fuel cell (ST100), Adjusting the state of the introduced air (ST200), Hydrogen introduced from the hydrogen supply unit Humidification of the gas (ST300), and supplying a regulated air and hydrogen gas to the stack (ST400) provides a method for controlling the exhaust gas recycle of the fuel cell, characterized in that it comprises a.

The adjusting of the state of the introduced air (ST200) detects the state of the outlet air discharged from the stack (ST210), and recycles the outlet air discharged from the stack according to the detected air state to mix with the outside air. It is preferably configured to include a step (ST220).

The step of adjusting the state of the introduced air (ST200) is a step of detecting the state of the outlet air discharged from the stack (ST210), according to the detected air condition to vary the amount of air outlet air discharged from the stack variably It is preferably configured to include the step of mixing with air (ST230).

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

When the outside air of the vehicle is introduced (ST100) through the air cleaner 2 using the air supply 10 (ST100), the dry air containing the relative humidity corresponding to a small proportion of the outside air introduced by the air supply 10 Air condition.

When the hydrogen gas supplied from the hydrogen supply unit 40 for supplying the external air and the hydrogen gas is supplied to the stack 30, the external air and the hydrogen gas supplied to the stack 30 cause a chemical reaction through an electrolyte, which is necessary. Generate voltage.

In the exit line of the stack 30 into which the external air is introduced by the chemical reaction occurring in the stack 30, humidified air having a relatively high temperature and high humidity is discharged compared to the external air before entering the stack 30.

That is, in order to operate the stack 30, air outside the vehicle is introduced (ST100), and then the state of the introduced air must be adjusted (ST200) to be supplied to the stack 30, and the outlet of the stack 30 The humidified air discharged from the line senses the state of air (temperature, relative humidity ...) in the sensing unit 70 installed in the outlet line of the stack 30 (ST210) and then controls the air state value described above. To send).

The control unit 70 which receives the sensing value of the sensing unit 70 operates the air recirculation fan 24 of the air volume control unit 20, while maintaining the amount of air required to operate the stack 30 in an optimal state. The fan speed of the air recirculation fan 24 is controlled to feed the mixer 22.

Return air whose air amount is adjusted by the air recirculation fan 24 is mixed with external air to the mixer 22 (ST220) and supplied to the stack 30.

Since the state of the air discharged from the stack 30 is a wet air state having a relative humidity close to 100% while passing through the stack 30, the hydrogen gas supplied from the hydrogen supply unit 40 is discharged from the stack 30. The hydrogen gas is humidified in the humidifying unit 50 using the outlet air (ST300) and supplied to the stack 30 together with the air mixed in the mixer 22 of the air amount adjusting unit 20 (ST400).

Preferably, the hydrogen gas discharged in a high temperature and high humidity state by installing a hydrogen recycle pump 60 for returning the hydrogen gas supplied to the outlet of the hydrogen supply line supplied to the stack 30 back to the inlet of the stack 30. Use

The air volume control unit 20 is installed by using the mixer 22, the air recirculation fan 24 described above, and the ejector 26 installed on the line where the air supply 10 and the stack 30 are connected. ) And a variable unit 28 for returning the air recovered from the outlet of the stack 30 to the ejector 26 can be installed and used to install and operate the ejector 26 and the variable unit 28 in detail. Explain.

The air state value at the outlet of the stack 30 is sensed by the sensing unit 70 installed in the outlet line of the stack 30 (temperature, relative humidity ...) (ST210). To the control unit 80.

The control unit 70 receiving the sensing value of the sensing unit 70 adjusts the return amount of air by using a variable orifice installed in the variable unit 28 of the air volume adjusting unit 20. The variable orifice is controlled to supply the ejector 26 with the amount of air necessary to be able to operate in this optimum state.

Return air whose air amount is adjusted by the variable orifice is mixed with external air to the ejector 26 (ST220) and supplied to the stack 30.

Therefore, the stack 30 is operable in an optimal state by recycling the wet air and hydrogen gas discharged from the stack into the stack 30 again without directly discharging it into the atmosphere.

On the other hand, the present invention can be variously modified by those skilled in the art without departing from the gist of the invention.

As described above, the exhaust gas recirculation apparatus and the control method of the fuel cell according to the present invention has the effect that the stack can operate in an optimal state by recovering and using the outlet air discharged from the stack.

In addition, there is no problem of freezing even in cold weather, such as winter, can be stored and operated even in sub-zero temperatures, it is advantageous to implement a fuel cell system for vehicles by reducing the number of parts.

Claims (7)

Air supply unit 10 for introducing the outside air of the vehicle through an air cleaner, an air amount adjusting unit 20 for controlling the state and air volume of the dry air introduced by the air supply 10, the air amount adjusting unit 20 In the stack 30 to which the controlled air flows in, the hydrogen gas supplied from the hydrogen supply unit 40 supplying the hydrogen gas is supplied to the stack 30, but by using humidified air discharged from the outlet of the stack 30. Humidification unit 50 for humidifying the hydrogen gas, hydrogen recycling pump 60 for returning the hydrogen gas supplied to the stack 30 through the humidifying unit 50 back to the inlet side of the stack 30, the stack 30 The control unit 70 for detecting the temperature and humidity of the outlet air, the control unit for controlling the speed and air volume of the air of the air volume control unit 20 by receiving the state value of the air detected by the detection unit 70 Characterized in that it comprises 80 The exhaust gas recirculation device of a fuel cell. The method of claim 1, The air amount adjusting unit 20 returns the mixer 22 installed on the line in which the air supply 10 and the stack 30 are connected and the air recovered from the outlet of the stack 30 to the mixer 22. Exhaust gas recirculation apparatus of the fuel cell, characterized in that it comprises an air recirculation fan (24). The method of claim 1, The air amount adjusting unit 20 returns the ejector 26 installed on the line where the air supply 10 and the stack 30 are connected and the air recovered from the outlet of the stack 30 to the ejector 26. Exhaust gas recirculation apparatus of the fuel cell, characterized in that it comprises a variable portion (28). The method of claim 3, The variable gas 28 is an exhaust gas recirculation apparatus of a fuel cell, characterized in that the variable orifice. delete Step of introducing air from the outside of the vehicle by the air supply (ST100), adjusting the state of the introduced air (ST200), humidifying the hydrogen gas introduced from the hydrogen supply unit (ST300), condition-conditioned air and hydrogen It comprises a step of supplying a gas to the stack (ST400), The adjusting of the state of the introduced air (ST200) detects the state of the outlet air discharged from the stack (ST210), and recycles the outlet air discharged from the stack according to the detected air state to mix with the outside air. Method for controlling the exhaust gas recirculation of the fuel cell comprising a step (ST220). Step of introducing air from the outside of the vehicle by the air supply (ST100), adjusting the state of the introduced air (ST200), humidifying the hydrogen gas introduced from the hydrogen supply unit (ST300), condition-conditioned air and hydrogen It comprises a step of supplying a gas to the stack (ST400), The step of adjusting the state of the introduced air (ST200) is a step of detecting the state of the outlet air discharged from the stack (ST210), according to the detected air condition to vary the amount of air outlet air discharged from the stack variably Mixing with air (ST230) comprising the exhaust gas recirculation control method of the fuel cell, characterized in that it comprises a.

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