KR100653672B1 - An apparatus for controlling humidity of gas for fuel cell - Google Patents

Abstract

A device for controlling the moisture of gas for a fuel cell is provided to obtain a desired humidity of a mixture fuel gas comprising a dry fuel gas and a moisturized fuel gas precisely by feedback control. The device comprises a fuel gas moisturization part(70) which moisturizes fuel gas; a three-way valve which comprises an inlet for fuel gas, a first outlet connected with the fuel gas moisturization part, a second outlet connected with the fuel cell side, and a flux control part; a position determination part(50) which controls the position of the flux control part; a moisture sensor(30) which detects the moisture of the mixture gas which comprises the moisturized fuel gas discharged from the fuel gas moisturization part and the dry fuel gas discharged from the second outlet; and a control part(40) which generates a feedback flux control signal based on the detected moisture signal until the desired moisture is obtained, to send it to the position determination part.

Description

An Apparatus For Controlling Humidity of Gas For Fuel Cell}

1 is a block diagram showing the configuration of a gas humidity control apparatus for a fuel cell according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a detailed structure of the positioning unit of FIG. 1.

3 is a block diagram showing the configuration of a gas humidity control apparatus for a fuel cell according to a second embodiment of the present invention.

<Description of the major reference numerals>

10 fuel gas tank 20 three-way control valve

30: humidity sensor 40: control unit

50: positioning unit 60: fuel cell

70: fuel gas humidifier 80: heater

90-1: 1st flow control part 90-3: 2nd flow control part

The present invention relates to a gas humidity control device of a fuel cell, and more particularly, a part of fuel gas is humidified by flowing into a fuel gas humidifying part while the fuel gas is constantly supplied, and a part of the fuel gas is mixed in a dry state. It relates to a gas humidity control device of the fuel cell that can precisely control the humidity of the mixed gas after the feedback control.

Recently, due to the depletion of fossil fuels and environmental pollution, many studies have been conducted to develop energy sources that can replace fossil fuels. In particular, efforts are being actively made to develop pollution-free alternative energy that can solve environmental pollution.

In particular, the development of fuel cells using hydrogen as an energy source has attracted much attention. Since hydrogen is easily obtained in the atmosphere and generates large energy by reacting with oxygen, only water is generated as a by-product, which has emerged as the only alternative to solve the problem of energy depletion and environmental pollution.

A fuel cell that uses hydrogen as a fuel is a device that converts hydrogen into electrochemically and directly into electrical energy. When hydrogen fuel is supplied, electrons are separated from hydrogen through a catalyst, and hydrogen ions are transferred through an electrolyte membrane and electrons are transferred through an external conductor. After the movement, water is produced by combining with oxygen in the air supplied as fuel to the opposite side of the electrolyte membrane. In order to allow hydrogen ions to easily pass through the electrolyte membrane, it is necessary to control the moisture of hydrogen and air supplied. Therefore, a humidifier for controlling humidity of supply hydrogen and air is essential for hydrogen and air supply of the fuel cell. Consists of.

The humidifier is a bubble type humidifier, and when hydrogen and air are supplied into the distilled water under the distilled water, the supplied hydrogen and air are humidified while rising upward above the distilled water in the form of a bubble. do.

Conventional humidifiers adjust the relative humidity by controlling the internal temperature by a heating device to adjust the humidity of the fuel gas. In other words, the temperature at which the amount of steam at a desired humidity at the temperature of the fuel cell is saturated is calculated to maintain the internal temperature of the humidifier at the calculated temperature.

However, this method is theoretically not unreasonable, but in practical applications, there are many problems in which a considerable error occurs due to various factors and thus a desired humidity cannot be obtained.

In addition, the adjustment of the relative humidity by temperature control has a problem in that it is difficult to control the relative humidity because the adjustment speed is slow because the amount of moisture vaporized by adjusting the temperature inside the humidifier.

Korean Patent Application No. 10-2004-81534 has proposed a humidity control device to adjust the pressure inside the humidifier by using a pressure control valve to adjust the humidity more quickly in view of the problems of the conventional humidifier.

However, the proposed invention is not preferable in the characteristic of the fuel cell that must be supplied with a certain amount of fuel gas at all times because the amount of hydrogen or air discharged to control the pressure, constant electricity according to the fluctuation of the supplied fuel gas There is a serious problem that the output voltage is not stable because it cannot produce energy.

The present invention has been made in order to solve the above problems, an object of the present invention is to supply a portion of the fuel gas humidified by the fuel gas humidifier in a state in which the fuel gas is constantly supplied, and the other part is passed through the dry state It is to provide a gas humidity control device of the fuel cell that can precisely control the humidity of the mixed gas by the feedback control after mixing.

According to an aspect of the present invention for achieving the above object, the fuel gas humidifying unit for maintaining the humidity of the fuel gas to a desired humidity by humidifying the fuel gas, the inlet for entering the fuel gas, the fuel gas humidifying unit and A three-way control valve including a first outlet connected thereto, a second outlet connected to a fuel cell side, and a flow rate adjusting unit configured to adjust a flow rate of fuel gas flowing into the inlet to the first outlet and the second outlet; Receiving from the humidity sensor and the humidity sensor for detecting the humidity of the position determination unit for controlling the position of the unit, the humidity of the mixed gas mixed with the humidified fuel gas discharged from the fuel gas humidifying unit and the dry fuel gas discharged through the second outlet Based on the detected humidity detection signal, the feedback flow control signal is generated until the desired humidity is obtained. It is provided with a gas humidity control device for a fuel cell comprising a control unit for transmitting to the positioning unit.

Here, the positioning unit is a position control unit for generating a position control signal based on the feedback flow control signal input from the control unit, electric / pneumatic for converting the position control signal into a pneumatic output signal corresponding to the magnitude of the position control signal A converting unit, an actuator for converting the pneumatic pressure converted by the electric / pneumatic converting unit into a mechanical motion, the flow rate control unit of the three-way control valve is coupled to the upper or lower by the actuator to control the flow rate control unit A feedback lever, a position measuring unit detecting a position of the feedback lever, and a position transmitting unit transmitting a position detecting signal of the feedback lever detected by the position measuring unit to the control unit, wherein the position detecting signal of the feedback lever is the position It is preferable to feed back to the input terminal of the control unit.

According to another aspect of the invention, the fuel gas humidifying unit for humidifying the fuel gas to maintain the humidity of the fuel gas at a desired humidity, the inlet is connected to the fuel gas supply and the outlet is connected to the fuel cell side, the fuel gas A first flow controller controlling a flow rate of the fuel gas flowing from the supply unit to the inlet port, the inlet port is connected to the fuel gas supply unit in parallel with the first flow controller, and the outlet port is connected to the fuel gas humidifying unit, and the fuel A second flow rate controller configured to adjust a flow rate of the fuel gas flowing into the inlet from the gas supply part, and a humidity of the mixed gas mixed with the dry fuel gas discharged from the first flow rate controller and the humidified fuel gas discharged from the fuel gas humidifier A humidity sensor for detecting an element based on a humidity detection signal received from the humidity sensor The control unit includes a control unit for generating a feedback flow control signal for controlling the flow rate of the fuel gas branched to the first flow rate control unit and the second flow rate control unit until the humidity is obtained, and transmits it to the first and second flow rate control unit. A gas humidity control device for a fuel cell is provided.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a block diagram showing the configuration of a gas humidity control apparatus for a fuel cell according to a first embodiment of the present invention.

As shown in FIG. 1, a gas humidity control apparatus for a fuel cell according to a first embodiment of the present invention includes a three-way control valve 20, a humidity sensor 30, a controller 40, and a positioning unit 50. And a fuel gas humidifying unit 70.

The fuel gas humidifying unit 70 is to humidify the dry fuel gas introduced from the fuel gas tank 10 to maintain a desired humidity, and the fuel gas humidifying unit 30 is located at the lower end of the fuel gas humidifying unit 30. Heater 40 for heating the water contained in the) to increase the humidity of the fuel gas is installed.

The rear end of the gas humidity control device is a fuel cell 100 for generating electrical energy using the humidified fuel gas is located.

The three-way control valve 20 is composed of one inlet and two outlets to control the rate at which the fluid flows into the two outlets, a control valve, which is not shown in the drawing, but the fuel inlet inlet And a flow rate control unit configured to adjust a flow rate ratio at which the first gas outlet connected to the fuel gas humidifying unit, the second gas outlet connected to the fuel cell, and the fuel gas flowing into the first gas outlet are discharged to the first gas outlet and the second gas outlet. do.

The flow rate ratio adjusting part is formed with a seat portion at the connection part of the pipe, the valve stem is located along the central axis of the pipe and the plug is connected to the lower end of the valve stem, the flow rate of the fuel gas flowing to each outlet is changed according to the position of the plug.

The humidity sensor 30 is for detecting humidity of the mixed gas in which the humidified fuel gas discharged from the fuel gas humidifying unit 70 and the dry fuel gas discharged through the second outlet are mixed.

The controller 40 generates a feedback flow control signal and transmits the feedback flow control signal to the positioning unit 50 until a desired humidity is obtained based on the humidity detection signal received from the humidity sensor 30. That is, a feedback flow rate control signal proportional to the difference between the preset humidity and the humidity measured from the humidity sensor 30 is input to the positioning unit 50 so that the humidity value of the mixed fuel gas is set by the feedback action. Controlled to be the same.

The positioning unit 50 controls the flow rate of the fuel gas flowing out to each outlet by moving the valve stem upward or downward according to the control signal of the controller 40, which will be described in detail with reference to FIG. 2. .

FIG. 2 is a block diagram illustrating a detailed structure of the positioning unit of FIG. 1.

The positioning unit is largely comprised of a control unit 51, an electric / pneumatic conversion unit 52, an actuator 53, a feedback lever 54, and a position measuring unit 55.

The control unit 51 again generates the position control signal based on the feedback flow control signal input from the control unit 40, and the position of the feedback lever 54 detected by the position measuring unit 55. The position transmitter 51-3 which transmits a detection signal to the control part 40, and the limit switch 51-5 for determining the movement limit position of the feedback lever 54 are comprised.

The electric / pneumatic conversion unit 52 is for converting the position control signal into a pneumatic output signal corresponding to the magnitude of the position control signal, and in detail, a piezoelectric for converting an electric input signal into a pneumatic output signal using a piezoelectric effect. A pilot for supplying supply air to the actuator 53 by moving the valve 52-3, the pressure regulator 52-1, the pilot diaphragm 52-5 that amplifies the converted pneumatic output signal, and a spool (not shown). It is comprised including the valve 52-7.

The actuator 53 converts the pneumatic pressure converted by the electric / pneumatic converter into mechanical motion to move the feedback lever 54 upward in the forward direction downward in the reverse motion in the forward motion.

The feedback lever 54 is coupled to the valve stem of the three-way control valve 20 to move the valve stem upward or downward by the actuator to control the flow rate ratio discharged to each outlet.

The position measuring unit 55 detects the position of the feedback lever 55, and the detected position signal is fed back to the input terminal of the position control unit 51 so that the operation of the actuator 53 until the feedback signal and the input signal are the same. This continues. The detected position signal is also transmitted to the position transmitter 51-3 and the limit switch 51-5.

The operation of the positioning unit 50 will be described briefly with reference to FIG. 2.

The control signal from the control unit 40 is input to the piezoelectric valve 52-3 through the position control unit 51-1, and the supply air is input to the piezoelectric valve 52-3 through the pressure regulator.

By the piezoelectric effect, the piezoelectric valve 52-3 generates a pneumatic output signal proportional to the magnitude of the input control signal, which is amplified in the pilot diaphragm 52-5 and then in the pilot valve 52-7. Operate a spool (not shown).

The supply air is supplied to the actuator 53 through a flow path formed by the movement of the spool to drive the actuator 53 to move the feedback lever 54 upward or downward.

The position measuring unit 55 detects the position of the feedback lever 54, generates a feedback signal corresponding thereto, and feeds it back to the input terminal. If the feedback signal is the same as the input signal, the actuator 53 stops operation, otherwise the input signal is applied to the piezoelectric valve 52-3 until both signals become the same.

3 is a block diagram showing the configuration of the gas humidity control device of the fuel cell according to the second embodiment of the present invention.

As shown in FIG. 3, the apparatus for controlling the gas humidity of the fuel cell according to the second embodiment of the present invention includes a fuel gas humidifying unit 70, a first flow rate controller 90-1, and a second flow rate controller 90-3. ), The humidity sensor 30 and the control unit 40 is configured.

The first flow control unit 90-1 has an inlet connected to the fuel gas tank 10 and an outlet connected to the fuel cell 60, and controls the flow rate of the fuel gas flowing into the inlet from the fuel gas tank 10. It is to.

The second flow control unit 90-3 is connected such that the inlet is branched to the fuel gas tank 10 in parallel with the first flow control unit 90-3, and the outlet is connected to the fuel gas humidifying unit 70. It is for regulating the flow rate of the fuel gas which flows in from the inlet (10).

That is, the fuel gas supplied from the fuel gas tank 10 branches into and flows into the first flow rate controller 90-1 and the second flow rate controller 90-3, and thus the fuel gas supplied from the fuel gas tank 10. The amount of is constant, and the fuel supplied to the fuel cell 60 in accordance with the ratio branched to the first flow rate control unit 90-1 and the second flow rate control unit 90-3 in a state where the supply amount of the fuel gas is kept constant The humidity of the gas can be controlled.

The humidity sensor 30 is for detecting the humidity of the mixed gas in which the dry fuel gas flowing out of the first flow rate controller 90-1 and the humidified fuel gas discharged from the fuel gas humidifying unit 70 are mixed.

The controller 40 branches fuel gas to the first flow controller 90-1 and the second flow controller 90-3 until the desired humidity is obtained based on the humidity detection signal received from the humidity sensor 30. A feedback flow rate control signal for controlling the flow rate of the gas is generated and transmitted to the first and second flow rate control units 90-1 and 90-3. Since the feedback control is performed by the control unit 40, the humidity control can be performed quickly and accurately compared to the conventional relative humidity method.

In the above embodiment, but limited to the humidity control method of the fuel cell, the present invention is not limited to this, it is obvious that the present invention can be applied to all the various humidity control devices that require precise humidity control.

According to the present invention as described above, in a state in which the fuel gas is constantly supplied, some of the fuel gas flows into the fuel gas humidification part to humidify and the other part is mixed by passing through the dry state to precisely control the humidity of the mixed gas by feedback control. There is an effect that can be controlled.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (3)

A fuel gas humidifying unit which humidifies the fuel gas and maintains the humidity of the fuel gas at a desired humidity; Adjusting the flow rate ratio that the fuel gas flows into the inlet, the first outlet connected to the fuel gas humidifying unit, the second outlet connected to the fuel cell side and the fuel gas flowing into the inlet to the first outlet and the second outlet A three-way control valve including a flow rate control unit; A positioning unit controlling a position of the flow rate ratio adjusting unit; A humidity sensor detecting a humidity of a mixed gas in which humidified fuel gas discharged from the fuel gas humidifying unit and dry fuel gas discharged through the second outlet are mixed; And And a controller configured to generate a feedback flow control signal and transmit the feedback flow control signal to the positioning unit until a desired humidity is obtained based on the humidity detection signal received from the humidity sensor. The method of claim 1, The positioning unit A position controller configured to generate a position control signal based on the feedback flow rate control signal input from the controller; An electric / pneumatic conversion unit converting the position control signal into a pneumatic output signal corresponding to the magnitude of the position control signal; An actuator for converting the pneumatic pressure converted by the electric / pneumatic conversion unit into a mechanical motion; A feedback lever coupled to the flow rate ratio adjusting unit of the three-way control valve and controlling the flow rate ratio adjusting unit by moving upward or downward by the actuator; A position measuring unit detecting a position of the feedback lever; And And a position transmitter for transmitting the position detection signal of the feedback lever detected by the position measurer to the controller. And a position detection signal of the feedback lever is fed back to an input terminal of the position control unit. A fuel gas humidifying unit which humidifies the fuel gas and maintains the humidity of the fuel gas at a desired humidity; A first flow rate controller connected to a fuel gas supply part, an inlet port connected to a fuel cell side, and controlling a flow rate of fuel gas flowing from the fuel gas supply part to the inlet port; A second flow rate controller connected to the fuel gas supply part in parallel with the first flow rate control part, the outlet port connected to the fuel gas humidification part, and controlling a flow rate of the fuel gas introduced from the fuel gas supply part to the inlet port; ; A humidity sensor detecting a humidity of a mixed gas in which the dry fuel gas flowing out of the first flow controller and the humidifying fuel gas discharged from the fuel gas humidifying unit are mixed; And On the basis of the humidity detection signal received from the humidity sensor, a feedback flow rate control signal for controlling a flow rate of fuel gas branched to the first flow rate control unit and the second flow rate control unit is generated until the desired humidity is obtained. And a control unit for transmitting to the second flow control unit.

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