KR20110089743A - Fuel cell system having improved humidification performance - Google Patents

Abstract

PURPOSE: A fuel cell system is provided to evenly humidify a membrane electrode assembly within a fuel cell stack and to prevent a flooding phenomenon and the damage of a membrane electrode assembly by reversely converting the direction of the air passing through the fuel cell stack. CONSTITUTION: A fuel cell system comprises a humidifier(30) humidifying the air, a fuel cell stack generating electricity using the humidified air as reaction gas, and a convert device. In the convert device, a plurality of fuel cell stacks are serially connected to the flow path of the air in order to successively pass through the humidified air; the moisture generated from the upstream stack is supplied to the downstream stack by the air successively passing through the fuel cell stacks; and the air which successively passes through the stacks from the humidifier is reversely converted.

Description

Fuel cell system having improved humidification performance

The present invention relates to a fuel cell system, comprising a humidifier for humidifying and supplying air, and a fuel cell system including a fuel cell stack for generating electricity using humidifying air supplied through the humidifier as a reaction gas.

A fuel cell is a kind of power generation device that converts chemical energy of fuel into electric energy by electrochemical reaction in the fuel cell stack without converting it into heat by combustion. It can also be applied to the power supply of electrical / electronic products, especially portable devices.

As an example of such a fuel cell, a polymer electrolyte membrane fuel cell (PEMFC), which is most frequently researched as a power source for driving a vehicle, has an electrochemical reaction on both sides of the membrane centered on an electrolyte membrane through which hydrogen ions move. Membrane Electrode Assembly (MEA) with attached catalyst electrode layer, Gas Diffusion Layer (GDL), which serves to distribute the reactors evenly and transfer the generated electrical energy, reactors and cooling water Gaskets and fastening mechanisms for maintaining airtightness and proper clamping pressure, and bipolar plates for moving the reactor bodies and cooling water.

In the case of a polymer electrolyte membrane fuel cell (PEMFC) used in a fuel cell vehicle, moisture is required for operation, and since moisture acts as a transport medium for H ^{+ in} the fuel cell, the humidity of the supply gas is directly related to fuel cell performance. . Accordingly, air (or oxygen), which is an oxidant supplied to the cathode of the fuel cell stack, is humidified at the air inlet side using a humidifier.

There are various types of humidifiers such as bubbler type, injection type, and adsorbent type. However, in the case of fuel cell vehicles, a relatively small membrane humidifier is applied because of limitations in the package. Membrane humidifiers have the big advantage of not requiring special power as well as the package side. The membrane humidifier allows the gas supplied to the cathode inlet end to receive heat and moisture from the hot and humid gas discharged from the cathode outlet end.

1 is a schematic diagram showing a state in which air is supplied after humidifying air using a membrane humidifier in a conventional fuel cell system. As shown in FIG. 1, the membrane humidifier is forcibly blown with dry air from outside air to the air blower 110. Passed through (120), wherein the supersaturated humidifying air containing water discharged from the cathode outlet of the fuel cell stack 130 is passed through the membrane humidifier (120), and the dry air is exchanged by moisture exchange between the supersaturated humidifying air and the dry air. Humidification is to be made, where the humidified air is supplied to the fuel cell stack (130).

Conventional membrane humidifiers are gas-to-gas membrane humidifiers using hollow fiber membranes. These membrane humidifiers are capable of high integration of hollow fiber membranes with a large contact surface area, so that sufficient humidification of the fuel cell stack is possible even at a small capacity. It is possible to recover moisture and heat contained in the gas discharged at a high temperature from the cathode of the fuel cell stack through the membrane humidifier and reuse it, thereby saving moisture and energy required for humidification.

On the other hand, in the case of a fuel cell using a polymer electrolyte membrane, when moisture is insufficient, the conductivity of hydrogen ions is reduced, and the contact resistance between the electrode and the electrolyte membrane is increased due to shrinkage of the electrolyte membrane. Too much moisture, on the other hand, causes water condensation on the electrodes, causing flotation, which hinders the diffusion of the reaction gas and reduces the performance of the fuel cell. Proper humidification is necessary to prevent this.

The reactant gas supplied to the fuel cell stack is air and hydrogen, and in the case of air, the humidified gas is humidified as needed through a humidifier before being supplied to the fuel cell stack. The humidified air flows into the fuel cell stack through the intake manifold, humidifies the membrane electrode assembly to increase ion conductivity, and is then discharged to the atmosphere or condenser through the exhaust manifold.

However, if the fuel cell stack continues to operate, the humidity and temperature of the membrane electrode assembly in contact with the intake manifold and the region in contact with the exhaust manifold vary. As a result, the humidity side of the intake manifold into which the wet air flows is high, so that a flooding phenomenon (water condensation in the reactant gas condenses) is likely to occur.

In addition, the exhaust manifold side through which the reaction gas used for the reaction is discharged may have low humidity, and thus the membrane electrode assembly may be partially dried to form holes. If the fuel cell stack continues to operate in this state, the hole becomes larger and becomes a factor of deteriorating the durability of the membrane electrode assembly and the efficiency of the fuel cell stack.

In addition, in a multi-stack fuel cell system using a plurality of fuel cell stacks, there is a problem as described above for each fuel cell stack and a problem in that a humidifier is provided for each fuel cell stack.

Accordingly, the present invention is invented to solve the above problems, and by changing the direction of the air passing through the fuel cell stack in the reverse direction, the membrane electrode assembly in the fuel cell stack is uniformly humidified at the same time as the conventional It is an object of the present invention to provide a fuel cell system capable of preventing flooding and damaging the membrane electrode assembly.

In addition, the present invention in the multi-stack system applying a plurality of fuel cell stack to the air supplied through a single humidifier sequentially pass through the plurality of fuel cell stack, the stack is sequentially generated by the air passing through the stack upstream It is an object of the present invention to provide a fuel cell system in which a sufficient amount of moisture is supplied to a downstream stack so that a plurality of fuel cell stacks can be evenly humidified overall by the humidifier.

In order to achieve the above object, the present invention, in the fuel cell system including a humidifier for supplying the humidified air and a fuel cell stack for generating electricity using the humidified air supplied through the humidifier as a reaction gas ,

A plurality of fuel cell stacks are connected in series on a movement path of air to sequentially pass air supplied through the humidifier, and are generated in an upstream stack by air sequentially passing through the plurality of fuel cell stacks. Moisture is supplied to the downstream stack,

It provides a fuel cell system having a humidification performance is improved, characterized in that it comprises a switching device for switching the stack passing direction of air passing through the stacks sequentially from the humidifier in the reverse direction.

In a preferred embodiment, in the plurality of fuel cell stacks, a first stack and a second stack are connected to each other through a first air line, and the first stack and the second stack form a second air line and a third air line, respectively. Connected with the humidifier through,

The humidifying air supplied from the humidifier through the second air line or the third air line is passed by the switching device in the order of the first stack to the second stack or the reverse of the second stack to the first stack. It is characterized by.

In addition, the switching device,

A switching damper installed at an outlet port of the humidifier to change a supply direction of air so that humidified air is supplied in a selected direction between the second air line and the third air line during up and down rotation;

It characterized in that it comprises an actuator for rotating the switching damper.

In addition, the switching damper is installed to separate the path passing through the hollow fiber membrane in the humidifier and the path passing around the hollow fiber membrane in the housing of the humidifier in a vertically rotated position,

Humidified air passing through the hollow fiber membrane by the switching damper is supplied to the upstream stack through the second air line or the third air line,

As exhaust air exhausted from the downstream stack is introduced into the peripheral space outside the hollow fiber membrane in the housing through the second air line or the third air line,

Humidification of the air passing through the hollow fiber membrane is made by the exhaust air exhausted from the downstream stack.

Accordingly, in the fuel cell system of the present invention, the direction of the air passing through the fuel cell stack is reversed, so that the membrane electrode assembly can be evenly humidified in the fuel cell stack, and at the same time, the conventional flooding phenomenon and the membrane electrode assembly Bar damage problem can be prevented, there is an advantage that the performance and durability of the stack is improved.

In addition, in the fuel cell system of the present invention, the air supplied through one humidifier is configured to sequentially pass through the plurality of fuel cell stacks, so that a sufficient amount of moisture generated in the upstream stack can be supplied to the downstream stack, As a result, the humidification performance in the stack is improved.

In addition, while the multi-stack structure is applied, the air can be reversed in the reverse direction with respect to the entire stacks, so that water can be supplied evenly within the entire stack.

In particular, in the fuel cell system of the present invention, when the wet air discharged from the upstream stack is used once more in the downstream stack, that is, by humidifying the downstream stack using water generated in the upstream stack, The size can be reduced as compared with the conventional one, and it is not necessary to provide a humidifier for each stack, thereby simplifying parts and reducing device costs.

1 is a schematic diagram showing a state in which air is supplied after humidifying using a membrane humidifier in a conventional fuel cell system.
2 is a block diagram showing a fuel cell system according to the present invention, which shows the humidification and supply state of air.
3 is a view showing a state in which the supply direction of air is switched by the switching device in the fuel cell system according to the present invention.
FIG. 4 is a cross-sectional view taken along the line 'A-A' in FIG. 2 and shows a state in which air flow paths are switched in the inner space of the membrane humidifier according to the upper and lower positions of the switching damper.
FIG. 5 is a block diagram of a configuration in which a controller controls an actuator, a first valve, and a second valve according to a brake operation in the fuel cell system according to the present invention.

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.

First, the fuel cell system according to the present invention may include a multi-stack structure in which a plurality of fuel cell stacks are connected in series. For example, two fuel cells connected in series as shown in FIGS. 2 to 3. It may be a configuration including the stack (10, 20).

The two fuel cell stacks, that is, the first stack 10 and the second stack 20 are individual fuel cell stacks having independent configurations and power generation functions, and each stack is configured as a fuel cell stack for a vehicle. Since the same configuration as (for example, a polymer electrolyte membrane type), description of each configuration will be omitted.

The first and second stacks 10 and 20 are basically supplied with air including hydrogen, which is a fuel, and oxygen, which is an oxidant, through a hydrogen supply device and an air supply device, which are not shown. And air are used as reaction gases to generate electricity through fuel cell reactions (electrochemical reactions).

In the fuel cell system including the multi-stack structure as described above, the first stack 10 and the second stack 20 are connected in series on a path through which air moves, and are supplied through the humidifier 30. Air passes through the first stack 10 and the second stack 20 in sequence.

Looking at the connection structure, the exhaust manifold 12 of the first stack 10 provided to discharge the air after the reaction, the intake manifold of the second stack 20 that is the air supply portion of the second stack 20 It is connected to the fold 21 and the first air line 13 made of a pipe or a hose, and the reaction gas from the first stack 10 to the second stack 20 through the first air line 13. Air can be moved and supplied. Of course, when air flows in the reverse direction as described below, the first air line 13 moves and supplies air from the second stack 20 to the first stack 10.

When the air is configured to pass through the first stack 10 and the second stack 20 in this manner, the air passing through the stack disposed upstream with respect to the air flow direction includes moisture generated in the upstream stack. Wet air, which is passed through the downstream stack to provide sufficient moisture to the downstream stack.

That is, while the air passing through the humidifier 30 sequentially passes through the upstream stack and the downstream stack, air containing water in the form of water vapor generated in the upstream stack is supplied to the downstream stack, and the downstream stack is supplied. In the air, the air and the moisture can be discharged after maximum use.

In general, since the amount of oxygen in the air consumed while the air passes through the stack once is a part of the total amount of oxygen (about 10%), the air supplied by the air supply means of the air supply device, for example, the air blower, Part of the oxygen in the air is consumed in the fuel cell reaction to produce electricity while passing through the humidifier 30 and then through the upstream stack, while air containing the remaining oxygen passes through the downstream stack and part of the oxygen therein. Is consumed for the fuel cell reaction of the downstream stack.

At this time, since the air sufficiently humidified by the moisture generated in the upstream stack is used to move from the upstream stack to the downstream stack, a sufficient amount of water required by the membrane electrode assembly or the like can be supplied to the downstream stack.

In the above description, if the air humidified through the humidifier 30 passes first through the first stack 10 of the illustrated embodiment for the fuel cell reaction and then passes through the second stack 20, the air flow direction. When the air supply direction / stack passage direction and the supply path are set, the first stack 10 becomes an upstream stack, and the second stack 20 becomes a downstream stack (see Fig. 2).

In the state of FIG. 2, the air supply path will be described in more detail. The air supplied by the air supply means such as an air blower is humidified after passing through the humidifier 30 to the first stack 10 which is an upstream stack. In this case, the air is supplied through the intake manifold 11 of the first stack 10 to be distributed to the air flow paths formed in the separator plates of each unit cell. Electricity is produced by reacting with the hydrogen supplied through the membrane.

In addition, the air discharged to the exhaust manifold 12 of the first stack 10 through the air flow path of each separation plate is wet air containing moisture generated in the first stack 10 in the first air line ( 13 is supplied to the intake manifold 21 of the second stack 20 which is the downstream stack. In the second stack 20, the air supplied to the intake manifold 21 is distributed to air passages formed in the separator plates of each unit cell, and the air distributed through the air passages of each separator plate reacts with hydrogen to generate electricity. To produce.

As described above, the air that has completed the reaction in the second stack 20 is discharged through the exhaust manifold 22, and the air discharged from the exhaust manifold 22 receives moisture generated in the second stack 20. It is discharged in the wet air containing.

The fuel cell system according to the present invention is configured to use the moisture of the wet air discharged from the second stack 20, that is, the downstream stack, to humidify the air supplied to the first stack 10, that is, the upstream stack. Can be.

That is, when the humidifier 30 is the membrane humidifier 30, while the air supplied by the air blower passes through the respective hollow fiber membranes 32 of the membrane humidifier 30 before being supplied to the upstream stack, the humidifier 30 is downstream. The wet air discharged from the side stack passes through an outer peripheral path of the hollow fiber membrane 32 in the housing 31 of the membrane humidifier 30, and the air passing through the hollow fiber membrane 32 is hollow fiber membrane 32. Moisture is supplied from the humid air passing through the outside (the air discharged from the downstream stack, that is, the cathode exhaust gas of the downstream stack), humidified and supplied to the upstream stack (supply to the cathode side through the intake manifold). being).

On the other hand, the fuel cell system according to the present invention is to change the flow direction (air supply direction / stack passing direction of the air) to pass through the first stack 10 and the second stack 20 in the forward and reverse directions And a switching device.

That is, humidifying air supplied from the humidifier 30 is supplied in the order of the first stack 10 and the second stack 20 according to the operating state of the switching device, or conversely, the second stack 20 and the first stack ( It is to be supplied in the order of 10).

To this end, the second air line 34 and the third air line 35 made of a pipe or a hose are branched and connected to the outlet port 33 connected to the outlet of the membrane humidifier 30. The air line 34 and the third air line 35 are connected to the intake manifold 11 of the first stack 10 and the exhaust manifold 22 of the second stack 20, respectively.

In addition, the outlet port 33 of the membrane humidifier 30 is provided with a switching damper 51 installed to rotate within the outlet of the membrane humidifier 30, and an actuator 52 for driving the switching damper 51 is provided with a membrane. It is installed outside the humidifier 30. The actuator 52 may be an electric motor for rotating the switching damper 51 up and down in the drawing.

The switching damper 51 serves to separate the humidified air passing through the hollow fiber membrane 32 into the upstream stack and the exhaust air discharged from the downstream stack and then introduced into the membrane humidifier outlet. As shown in Figure 3 serves to reverse the flow direction of air in the second air line 34 and the third air line (35).

In particular, the switching damper 51 separates the path passing through the hollow fiber membrane 32 and the path passing through the outer periphery of the hollow fiber membrane 32 in the housing 31 in a state of upward rotation or vice versa. , The air passing through the hollow fiber membrane 32 is humidified by receiving moisture from the air passing through the outer peripheral path of the hollow fiber membrane 32.

However, the wet exhaust air exhausted from the downstream stack (which is the stack of the first stack and the second stack in the present invention) while the switching damper 51 is rotated in one of the upward and downward directions. It is discharged to the outer peripheral path of the hollow fiber membrane 32 in the housing 31 and is discharged through the exhaust port 36 provided at the rear end of the housing 31, and the wet exhaust air passes through the outer peripheral path of the hollow fiber membrane 32. During the passage, the moisture is delivered to the air passing through the hollow fiber membrane 32 to be humidified.

As such, the air passing through the hollow fiber membrane 32 is humidified by wet exhaust air passing through the outer peripheral path of the hollow fiber membrane, and is then an upstream stack (which is one of the first stack and the second stack in the present invention). ) To be used for fuel cell reaction.

In addition, among the front end fixing part 37 and the rear end fixing part 38 for fixing and supporting the hollow fiber membrane 32 in the housing 31 in the membrane humidifier 30, the switching damper 51 is provided. According to the operating state of the) is a discharge hole 39 for discharging the exhaust air exhausted from the first stack 10 or the second stack 20 to the peripheral space outside the hollow fiber membrane in the housing.

At this time, the discharge hole 39 is respectively installed at the upper position and the lower position on the drawing in the front fixed portion 37, each discharge hole 39 and the first valve 53 and the agent for selectively blocking the discharge of air Two valves 54 are provided.

In other words, on one side and the other side of the shear fixing part 37 which fixes and supports the hollow fiber membrane 32 so that the exhaust air exhausted from the downstream stack can be introduced into the outer periphery of the hollow fiber membrane 32 in the housing 31. Each of the discharge holes 39 for passing the discharged air discharged through the second air line 34 or the third air line 35 at the position where the switching damper 51 is rotated up and down is formed, and each discharge hole is formed. The first valve 53 and the second valve 54 for selectively blocking 39 are provided.

Here, the first valve 53 and the second valve 54, the plunger 56 is moved forward and backward in the valve body 55, in particular, an electric type to block and seal the corresponding discharge hole 39 when moving forward It can be implemented with a solenoid valve.

As a result, as shown in Fig. 2, when the switching damper 51 is rotated downward in the drawing, the first valve 53 is closed and the second valve 54 is opened, the air blower Dry air supplied from the air is supplied through the inlet of the membrane humidifier 30 to pass through the inside of the hollow fiber membrane 32, thereby passing through the inside of the hollow fiber membrane 32, and then the outlet and outlet ports of the membrane humidifier 30. The air discharged through the 33 is a path leading to the second air line 34, the first stack 10, the first air line 13, the second stack 20, and the third air line 35. Will flow along.

Subsequently, the air circulated through the path is introduced into the outlet and the outlet port 33 of the membrane humidifier 30 through the third air line 35 and the hollow fiber membrane in the housing 31 of the membrane humidifier 30 is formed. 32) After passing through the outer peripheral path is discharged to the exhaust port (36).

In this process, the first stack 10 becomes an upstream stack, the second stack 20 becomes a downstream stack, and the air passing through the first stack 10 that is the upstream stack is the first stack 10. Passing through the second stack 20, which is a downstream stack, in a wet state together with the moisture generated therein, a sufficient amount of water is generated by the moisture generated in the first stack 10. Can be supplied. Thus, in the present invention, a sufficient amount of water can be supplied to the downstream stack by the moisture generated in the upstream stack.

In addition, the wet exhaust air exhausted from the second stack 20 passes through the outer peripheral path of the hollow fiber membrane 32 in the housing 31 of the membrane humidifier 30, and the air passes through the hollow fiber membrane 32. After the humidification, the first stack 10 can receive air sufficiently humidified by the moisture of the exhaust air exhausted from the second stack 20 from the membrane humidifier 30.

On the contrary, as shown in FIG. 3, when the switching damper 51 is rotated upward in the drawing, the first valve 53 is opened and the second valve 54 is closed, the air blower is turned on. Air supplied to the inlet of the membrane humidifier 30 and passed through the hollow fiber membrane 32 is discharged from the outlet and outlet ports 33 of the membrane humidifier 30 to the third air line 35 and the second stack 20. ), Along the path leading to the first air line 13, the first stack 10, and the second air line 34, flows in the opposite direction to the state of FIG. 2.

Subsequently, the air circulated through the path is introduced into the outlet and the outlet port 33 of the membrane humidifier 30 through the second air line 34 again, and the hollow fiber membrane in the housing 31 of the membrane humidifier 30 32) After passing through the outer peripheral path is discharged to the exhaust port (36).

In this process, the second stack 20 becomes an upstream stack, the first stack 10 becomes a downstream stack, and the air passing through the second stack 20 that is the upstream stack is the second stack 20. Passing through the first stack 10, which is a downstream stack, in a wet state with the moisture generated therein, a sufficient amount of water is generated by the moisture generated in the second stack 20. Can be supplied.

In addition, while the wet exhaust air exhausted from the first stack 10 passes through a peripheral path outside the hollow fiber membrane 32 in the housing 31 of the membrane humidifier 30, the air passing through the hollow fiber membrane 32 is discharged. After being humidified, the second stack 20 may receive air sufficiently humidified by the moisture of the exhaust air exhausted from the first stack 10 from the membrane humidifier 30.

On the other hand, the actuator 52, the first valve 53, and the second valve 54 of the switching damper 51 are controlled by the controller 2 as shown in FIG. 5, and the controller 2 is the actuator. 52 and each of the valves 53 and 54 are controlled to switch the air flow direction, that is, the air intake and exhaust directions, at regular time intervals during the operation of the fuel cell.

Instead of the control method of switching the air flow direction in the reverse direction at a predetermined time interval as described above, the controller 2 receives a separate operation signal input during the driver's vehicle operation and uses the operation signal as an input signal. It may be set to perform a control for switching the flow direction in the reverse direction.

Preferably, the operation signal may be a brake operation signal input from the brake pedal switch 1 mounted on the vehicle. In this case, even if the driver does not consciously perform a separate operation, the controller 2 may receive an operation signal from the brake pedal switch 1 whenever the driver's brake operation is repeatedly performed during driving. Control to switch the direction of flow of can be performed. That is, the controller 2 receives the on / off signal of the brake pedal switch 1 and controls the actuator 52 and each valve of the switching damper 51 on the basis of this.

At this time, in the driving state without brake operation (brake pedal switch off), the controller 2 controls the switching damper 51, the first valve 53, and the second valve 54 in the state shown in FIG. In the state where the brake pedal is pressed down (brake pedal switch on), the controller 2 controls the switching damper 51, the first valve 53, and the second valve 54 in the state shown in FIG.

As such, the controller 2 receives input of a predetermined vehicle operation signal at a predetermined time interval or the driver in the air flow direction (intake and exhaust directions) of the membrane humidifier 30, the first stack 10, and the second stack 20. ) Can be switched between the state of FIG. 2 and the state of FIG. 3, so that water can be supplied evenly throughout the first stack 10 and the second stack 20, and the membrane electrode assembly in the entire stack is sufficiently wetted. It can maintain the same condition and improve the overall humidification performance of the fuel cell system.

In addition, as in the related art, a problem in which flooding occurs in a specific part of the stack or damage of the membrane electrode assembly due to drying may be solved.

In addition, in the fuel cell system of the present invention, as the wet air discharged from the upstream stack is used once more in the downstream stack, the size of the humidifier can be reduced compared with the conventional one, and it is necessary to provide a humidifier for each stack. This, in turn, simplifies parts and reduces device costs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. Modified forms are also included within the scope of the present invention.

10: first stack 11: intake manifold
12: exhaust manifold 20: second stack
21: intake manifold 22: exhaust manifold
30: humidifier 31: housing
32: hollow fiber membrane 37: shear fixing part
39: discharge hole 51: switching damper
52: actuator 53: first valve
54: second valve

Claims (7)

In the fuel cell system comprising a humidifier 30 for humidifying and supplying air, and a fuel cell stack for generating electricity using the humidifying air supplied through the humidifier 30 as a reaction gas,
The plurality of fuel cell stacks 10 and 20 are connected in series on a movement path of air so that the air supplied through the humidifier 30 may sequentially pass through the plurality of fuel cell stacks 10 and 20. Moisture generated in the upstream stack is supplied to the downstream stack by air passing through the
And a switching device for switching the stack passing direction of air passing through the stacks (10, 20) sequentially from the humidifier (30) to the reverse direction.
The method according to claim 1,
In the plurality of fuel cell stacks, the first stack 10 and the second stack 20 are connected to each other through the first air line 13, and the first stack 10 and the second stack 20 are respectively. Is connected to the humidifier 30 through the second air line 34 and the third air line 35,
Humidifier air supplied from the humidifier 30 through the second air line 34 or the third air line 35 is in the order of the first stack 10 → the second stack 20 by the switching device or the like. A fuel cell system having improved humidification performance, characterized in that the second stack (20) → the first stack (10) in the reverse direction to pass through.
The method according to claim 2,
The switching device,
Installed at the outlet port 33 of the humidifier 30 to switch the supply direction of the air so that the humidified air is supplied in the selected direction of the second air line 34 and the third air line 35 during the up and down rotation A damper 51;
And an actuator (52) for rotating the switching damper (51).
The method according to claim 3,
The switching damper 51 passes through the hollow fiber membrane 32 inside the humidifier 30 at a position rotated up and down, and surrounds the outer periphery of the hollow fiber membrane 32 in the housing 31 of the humidifier 30. Is installed to separate the passage through
Humidified air passing through the hollow fiber membrane 32 by the switching damper 51 is supplied to the upstream stack through the second air line 34 or the third air line 35,
As exhaust air exhausted from the downstream stack is introduced into the peripheral space outside the hollow fiber membrane 32 in the housing 31 through the second air line 34 or the third air line 35,
Humidification performance is improved, characterized in that the humidification of the air passing through the hollow fiber membrane (32) by the exhaust air exhausted from the downstream stack.
The method according to claim 4,
On one side and the other side of the shear fixing part 37 for fixing and supporting the hollow fiber membrane 32 so that the exhaust air exhausted from the downstream stack is introduced into the outer periphery of the hollow fiber membrane 32 in the housing 31. A discharge hole 39 for passing the discharged air discharged through the second air line 34 or the third air line 35 at the position where the switching damper 51 is rotated up and down is formed,
The humidifier 30 is characterized in that the first valve (53) and the second valve (54) for selectively blocking each discharge hole (39) is installed, characterized in that the humidification performance is improved fuel cell system.
The method according to claim 5,
The actuator 52 driving the switching damper 51 and the first valve 53 and the second valve 54 are controlled by the controller 2, and the controller 2 is operated by the actuator ( 52) to control the driving of the first valve 53 and the second valve 54 to switch the stack stacking direction of the air at predetermined time intervals or to switch the stack stacking direction of the air each time a vehicle operation signal is input by the driver. A fuel cell system, characterized in that the humidification performance is improved.
The method of claim 6,
And the vehicle operation signal is a brake operation signal.

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