JP2001351660A - Supply gas humidifying device for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To humidify a macromolecular film appropriately by making the most of cost performance of low pressure driving system. SOLUTION: The supply gas humidifying device for the fuel cell comprises a moisture permeable humidifier 23 humidifying a supply gas (supplied air As, supplied hydrogen Hs) to be supplied to the fuel cell 1, which contains the moisture recovered from an exhaust gas (exhausted air Ae, exhausted hydrogen He) exhausted from the fuel cell 1, an exhaust gas transport means (compressor 24) arranged at the downstream side of the fuel cell 1, and a condensing means (condenser 26) condensing the moisture contained in the exhaust gas at the downstream side of the moisture permeable humidifier 23. The quantity of the moisture of supply gas at the upper stream side of the exhaust gas transport means is controlled by using the moisture condensed at the condensing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell for generating electricity by a chemical reaction between hydrogen and oxygen,
The present invention relates to a supply gas humidifier for a fuel cell which collects moisture in an exhaust gas discharged from a fuel cell and humidifies a supply gas supplied to the fuel cell.

[0001]

2. Description of the Related Art FIG. 3 shows a conventional fuel cell of this type.
As shown in FIG. 1, the fuel cell 101 has a cathode electrode side on one side and an anode electrode side on the other side with a solid polymer membrane 101c as an electrolyte membrane interposed therebetween.
Cathode electrode 101b containing catalyst, anode electrode 10
1d is provided. The solid polymer membrane 101c is made of, for example, a perfluorocarbon sulfonic acid membrane which is a proton exchange membrane, functions as a proton conductive electrolyte when saturated with water, and has a low specific resistance of 20Ω-proton or less at room temperature. The catalyst contained in the cathode electrode 101b generates oxygen ions from oxygen,
The catalyst contained in d generates protons from hydrogen. Cathode-side gas passage 101a for flowing supply air As as an oxidant gas outside cathode electrode 101b
In addition, an anode-side gas passage 101e for flowing supply hydrogen Hs as a fuel gas is defined outside the anode electrode 101d. When the supply air As flows through the cathode-side gas passage 101a and the supply hydrogen Hs flows through the anode-side gas passage 101e, hydrogen is ionized by the action of the catalyst of the anode electrode 101d to generate protons. Protons move through the solid polymer membrane 101c as an electrolyte membrane and reach the cathode electrode 101b. At this time, the protons react with oxygen ions generated from the oxygen of the supply air As in the presence of the catalyst to generate water. Supply air A containing product water and unused oxygen
s is exhausted from the cathode-side gas passage 101a of the fuel cell 101 as exhaust gas Ae. Anode electrode 10
In 1d, when hydrogen is ionized, electrons are generated, and the electrons are passed through an external load such as a motor M to the cathode electrode 1d.
01b.

FIG. 4 shows a conventional fuel cell system. As shown, the fuel cell system 111 includes an air transfer passage 112 for flowing an oxidizing gas through the fuel cell 101 and a hydrogen transfer passage 113 for flowing hydrogen as a fuel gas. Have.

The air transfer passage 112 is provided in the fuel cell 10
An air supply passage 112a for supplying air as an oxidizing gas to the first cathode-side gas passage 101a, and an air discharge passage 112b for discharging the exhaust air discharged from the cathode-side gas passage 101a. The transfer passage 113 includes a hydrogen supply passage 113a that supplies hydrogen to the anode-side gas passage 101e of the fuel cell 101,
A hydrogen discharge passage 113 for discharging the hydrogen He discharged after the reaction discharged from the anode electrode side gas passage 101e.
b.

[0004] An air cleaner 121 is provided upstream of the air supply passage 112a for purifying air and supplying it downstream. The air cleaner 121 collects moisture from the discharged air in the air supply passage 112a and the air discharge passage 112b. A water permeable membrane humidifier 123 is attached to humidify the supply air. A hydrogen supply source 131 for supplying hydrogen to the upstream end is attached to the hydrogen supply passage 113a. A regulator 132 for adjusting pressure and a hydrogen supply source for supplying hydrogen are provided downstream of the hydrogen supply source 131. A hydrogen circulation pump 133 is interposed. In addition, the hydrogen discharge passage 113
b, a three-way valve 134 for switching between the hydrogen circulation pump 133 side and the discharge side is interposed. A pressure control valve 125 for adjusting back pressure is provided downstream of the water permeable membrane humidifier 123. It is interposed. A water tank 127 supplies water for humidification, and supplies water to the air transfer passage 112 via an injector (not shown) as necessary.

[0005]

As described above, in the conventional fuel cell system, water is recovered from the discharge air side by the water permeable membrane type humidifier, and the supplied air is humidified by the recovered water. Considering that the evaporation rate of water is inversely proportional to the pressure when the temperature is constant, the required amount of water per fixed volume (volume) is constant when the pressure is changed, even if the set dew point of the air supplied to the fuel cell is the same. Changes,
In some cases, the humidification amount is insufficient only with the amount of water supplemented from the exhaust air of the fuel cell.

For example, a pump is installed on the upstream side of the cathode-side gas passage and air is transferred by positive pressure. (A) A high-pressure operation system, and a pump is installed on the downstream side of the cathode-side gas passage and negative pressure is installed. (B) When compared with the low-pressure operation system, the low-pressure operation system has a smaller pressure loss than the (a) high-pressure operation system and is superior in terms of power, but has a constant volume. There is a disadvantage that the required amount of water per (volume) increases. For this reason, the humidification amount of the polymer film is not sufficient only with the moisture supplemented from the exhaust air, and a power generation failure may occur due to an insufficient humidification amount of the supply gas even in the steady operation.

Although it is expected that the water permeable membrane type humidifier is scaled up to cope with a shortage of humidification, it is difficult to adopt the humidifier due to concerns about an increase in pressure loss.
Therefore, there is a technical problem to be solved in order to humidify the solid polymer membrane without excess or shortage by making use of the economy of the low-pressure operation system, and an object of the present invention is to solve the problem. .

Incidentally, as a prior art of the water permeable membrane type humidifier, there is known a humidifier having a hollow fiber membrane for transmitting moisture from a high humidity side to a low humidity side of a gas flowing in and out of the humidifier (Japanese Patent Application Laid-Open No. HEI 9-208). 8-273687 etc.).

[0009]

Means for Solving the Problems The invention according to claim 1 is proposed to achieve the above object, and recovers the moisture in the exhaust gas discharged from the fuel cell and supplies it to the fuel cell. In a supply gas humidifier for a fuel cell having a water permeable membrane humidifier for humidifying a supply gas, an exhaust gas transfer unit provided on the downstream side of the fuel cell, and the exhaust gas transfer unit on a downstream side of the water permeable membrane humidifier. A fuel for adjusting the humidification amount of the supply gas, comprising: a condensing means for condensing water contained in the exhaust gas; and an auxiliary humidifying means for supplying the water condensed by the condensing means to an upstream side of the exhaust gas transfer means. A battery supply gas humidifier is provided. Further, according to a second aspect of the present invention, in the fuel cell supply gas humidifier of the first aspect, the auxiliary humidifying unit is configured to select one of a required humidification amount of the fuel cell and a humidification amount of the water-permeable membrane humidifier. An object of the present invention is to provide a supply gas humidifier for a fuel cell which is controlled based on one of the above.

Further, according to a third aspect of the present invention, in the fuel cell supply gas humidifying apparatus according to the first or second aspect, the fuel is provided with a pressure control means for controlling the pressure of the exhaust gas downstream of the condensing means. A battery supply gas humidifier is provided.

According to the first aspect of the present invention, the pressure on the upstream side and the pressure on the downstream side are centered on the exhaust gas transfer means. The water permeable membrane humidifier collects the moisture in the exhaust gas discharged from the fuel cell and humidifies the gas supplied to the fuel cell. The condensing means collects water contained in the exhaust gas by condensation on the downstream side of the water permeable membrane humidifier, and the auxiliary humidifying means collects the condensed water on the upstream side of the exhaust gas transfer means.
Alternatively, replenish the fuel upstream of the fuel cell. For this reason, the supply gas contains an amount of moisture necessary for stable power generation of the fuel cell, and stable power generation is maintained. In this case, as in the invention according to claim 2, the amount of water supply is Preferably, the control is performed based on one of the required humidification amount of the fuel cell and the humidification amount of the water permeable membrane humidifier.

Further, during the operation of the fuel cell, the exhaust gas transfer means causes a downstream side (discharge side) of the exhaust gas transfer means.
Is necessarily higher than the pressure on the upstream side (suction side), and the water obtained by the condensing means can be sent naturally. However, the pressure on the downstream side (discharge side) of the exhaust gas transfer means is caused by the humidification assisting means. It is also assumed that the pressure is lower than the operating pressure or lower than the pressure at which a sufficient response speed is obtained. For this reason, in the invention according to claim 3, pressure control means is provided downstream of the condensing means for controlling the pressure of the exhaust gas, and the reliability and responsiveness of the humidification assisting means are improved by this control means. I have.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel cell system used as a vehicle power plant will be described below with reference to the accompanying drawings.

FIG. 1 shows a fuel cell system having a water-permeable membrane type humidifier.

The fuel cell system 20 includes a fuel cell 1
And an air transfer passage 2 for transferring air as an oxidizing gas to the fuel cell, and a hydrogen transfer passage 3 for flowing hydrogen as a fuel gas.
An air supply passage 2a for supplying air to the cathode-side gas passage 1a of the fuel cell 1 and an air discharge passage 2b for discharging the exhaust air Ae discharged from the cathode-side gas passage 1a. An air cleaner 21 is provided upstream of the air supply passage 2a so that purified air is supplied downstream. The air supply passage 2a and the air discharge passage 2b are supplied from the discharged air Ae to the supply air As.
A water permeable membrane type humidifier 23 is attached to collect moisture. The air discharge passage 2b has a water permeable membrane type humidifier 23b downstream from the cathode electrode side gas passage 1a.
Upstream of the compressor 2 as exhaust gas transfer means
A pressure control valve 25 is attached downstream of the water permeable membrane type humidifier 23 as pressure control means for controlling the pressure of gas.

The water permeable membrane humidifier 23 mainly comprises a case 23a as an outer shell and a hollow membrane 23b for moisture exchange.
Consists of The hollow element membrane 23b is configured to transmit moisture from the high humidity side to the low humidity side of the gas flowing inside and outside the hollow element membrane 23b, and, for example, to the air supply passage 2a and the air discharge passage 2b. The supply air As is installed so as to pass outside the hollow membrane 23b so that the exhaust air Ae passes through the inside of the hollow membrane 23b, and while the exhaust air Ae passes through the inside of the hollow membrane 23. The exhaust air Ae is attached so as to be recovered by the supply air As flowing outside.

The hydrogen transfer passage 3 is provided with a hydrogen supply passage 3a for supplying the supply hydrogen Hs to the anode-side gas passage 1e of the fuel cell 1, and a reaction-discharged hydrogen He discharged from the anode-side gas passage 1e. And a hydrogen discharge passage 3b for discharging. At the upstream end of the hydrogen supply passage 3a, for example, a hydrogen supply tank (not shown) is attached as a hydrogen supply source for supplying hydrogen, and a hydrogen supply source (not shown) is provided.
Toward the downstream side, a regulator (not shown) for pressure regulation and a hydrogen circulation pump (not shown) are sequentially provided. A three-way valve (not shown) is provided in the hydrogen discharge passage 3b to switch and transfer the discharged hydrogen He to the hydrogen circulation pump side or the discharge side.

For this reason, when the hydrogen circulation pump and the compressor 24 as the exhaust gas transfer means are operated,
Electric power is generated by a chemical reaction between the supply air As passing through the cathode gas passage 1a of the fuel cell 1 and the supply hydrogen Hs passing through the anode gas passage 1e, and reaction water is generated by the power generation. Then, the air (discharged air Ae) sucked from the cathode electrode side gas passage 1a of the fuel cell 1 and then compressed by the compressor 24 and the air cleaner 21
The supply air As filtered by the heat exchanger (not shown)
Heat is exchanged, and as a result, the supply air As is heated to a predetermined temperature (about 60 to 75 ° C.).

For this reason, the operating temperature of the fuel cell 1 is 80 to
Although the temperature is about 90 ° C., the evaporation rate of water is inversely proportional to the pressure when the temperature is constant, so that the evaporation rate of the reaction water increases under low pressure due to the negative suction pressure of the compressor 24,
The reaction water evaporates without excessively wetting the polymer membrane.
For this reason, the required amount of moisture per fixed volume (volume) increases, and the humidification amount to the supply air may be insufficient as a result, and a means for adjusting the humidification amount to maintain normal power generation is required.

In this embodiment, the air discharge passage 2
downstream of the water permeable membrane type humidifier 23 in FIG.
Condenser 26 as a condensing means to recover more residual moisture
The condenser 26 is provided with water spray means for supplying condensed water (recovered water) to the supply air As.

The condenser 26 as the condensing means only needs to be able to recover the water in the exhaust air Ae by condensation, and is not limited to the type of condensation. In the present embodiment, in order to improve the overall efficiency of the fuel cell system 20, a cylindrical metal container having a closed upper part and a lower funnel-shaped part is used as a condenser body, and is internally pumped therein. The exhaust air Ae is swirled, and condensed water is obtained by contacting or colliding with the inner wall surface of the main body of the water particles while rising while swirling. The condensed water is provided downstream of the water permeable membrane type humidifier 23 through the condenser 26. Has been established. A storage portion (not shown) for storing condensed water is attached to a lower portion of the condenser 26, and a water injection valve 26b as auxiliary humidifying means is attached to the storage portion via a communication passage 26a. An auxiliary water tank 26d for replenishing water through the communication passage 26c is attached to the upper part of the tank 26.

An opening / closing valve 26e for supplying water is provided in a communication passage 26c for communicating the condenser 26 with the auxiliary water tank 26d, and a water injection valve 26b as auxiliary humidifying means is provided.
Is connected between the cathode-side gas passage 1a and the water-permeable membrane humidifier 23 via a communication passage 26h.

The water injection valve 2 is disposed before and after the water injection valve 26b.
Pressure sensor (not shown) to detect pressure before and after 6b
And the pressure difference between the pressure upstream of the compressor 24 and the internal pressure of the condenser 26, that is, the water injection valve 26
When it is determined that the pressure difference between the front and rear pressures of b is lower than the pressure at which water can be injected, the liquid level in the reservoir of the condenser 26 is increased by the pressure control valve (back pressure valve) 25 as pressure control means. Although it is configured, a compressor 28a or a pump (not shown) may be separately provided to improve the response of pressurization. When the compressor 28a is provided, an air cleaner 28b is installed at the air inlet of the compressor 28a for pressurizing air for cleaning.

Accordingly, when the compressor 24 in the air discharge passage 2b is operated, the pressure on the upstream side of the compressor 24 decreases due to the suction of the compressor 24, and the pressure on the downstream side of the compressor 24 increases. The water generated by the reaction between hydrogen and oxygen evaporates due to a pressure drop caused by the suction of the compressor 24 and is transported downstream together with the water contained in the exhaust air Ae discharged from the fuel cell 1. The water is condensed by the condenser 26 and is stored in the storage portion. By controlling the opening and closing of the on-off valve 26e and controlling the pressure difference between the front and rear of the water injection valve 26b, it is possible to properly apply the gas to the cathode electrode side gas passage 1a. A quantity of water can be supplied in an atomized state.

In this embodiment, in order to adjust the supply amount of water, the humidity of the supply air As or the humidity for detecting the dew point is supplied to the air supply passage 2a upstream of the cathode-side gas passage 1a. A sensor T1 or a dew point sensor (not shown) is attached, and its output value is
And the controller ECU controls the opening / closing of the open / close valve 26e and controls the water injection valve 26b and the pressure regulating valve (back pressure valve) 25 or the separately provided compressor 28a or pump (not shown). It is configured to be.

FIG. 2 shows one form of control by the controller ECU. This control is executed every predetermined time. The controller ECU includes a known microcomputer.

First, a target power generation voltage value or a target power generation current value of the fuel cell 1 is confirmed (S1), and then a dew point or humidity required for power generation is calculated based on the target power generation voltage value or the target power generation current value. (S2). Thereafter, it is determined whether or not the humidifying ability of the permeable membrane type humidifier 23 is satisfied with respect to the humidifying conditions for the current operation, that is, whether or not only the water permeable membrane type humidifier 23 has sufficient humidification (S
4) If insufficient (NO), the condenser 26
It is determined whether or not a predetermined amount of water is stored in the storage section, that is, whether or not the predetermined amount of water is in the condenser 26 (S5). In this case, the water level in the reservoir of the condenser 26 is determined by the liquid level sensor L1 shown in FIG. According to the determination (S5), when a sufficient amount for the water injection is not ensured in the storage section of the condenser 26, that is, NO
In this case, the on-off valve 2 is kept until the water level in the reservoir of the condenser 26 from the liquid level sensor L1 becomes sufficient for water injection.
6e to open the auxiliary water tank 26d from the condenser 26d.
(S10).

When it is determined whether or not the predetermined amount of water is in the storage portion of the condenser 26 (S5), when the water level in the storage portion of the condenser 26 is sufficient for water injection, that is, when YES Is the differential pressure between the pressure upstream of the compressor 24 and the internal pressure of the condenser 26 from the detection values of the pressure sensors (not shown) arranged before and after the water injection valve 26b, that is, the water injection valve 26b Then, it is determined whether or not the pressure is lower than the pressure at which water can be injected based on the pressure difference (S6).

As a result of the determination (S6), when the pressure difference between the front and rear pressures of the water injection valve 26b is lower than the pressure at which water can be injected, the pressure control valve (back pressure valve) 25 is closed (currently opened). (S7), the back pressure of the water injection valve 26b is set to the water injection pressure to pressurize the liquid level in the reservoir of the condenser 23, and the cathode electrode side gas passage 1a Is sprayed upstream of the air to assist humidification of the supply air As. In this case, humidification is performed by the humidity sensor T.
1 or the detected value of the dew point sensor is the target generated current value,
Alternatively, it assists until the humidity corresponding to the target power generation voltage value or the dew point is reached (S8). In the determination (S6), when the differential pressure between the pressure upstream of the compressor 24 and the internal pressure of the condenser 26, that is, the differential pressure between the front and rear pressures of the water injection valve 26b is higher than the pressure at which water can be injected. Then, the process proceeds to step S8, where the above-described assisting of the humidification of the supply air As is executed, and then the control is ended (S9).

In step S8, to improve the responsiveness of water injection and the responsiveness of humidification assistance,
Separately, at the same time as the closing operation of the pressure control valve 25, the liquid level of the storage portion of the condenser 26 may be pressurized by a compressor 28a or a pump (not shown) separately provided.

On the other hand, in the determination (S4) as to whether the humidifier 23 is sufficient only with the water permeable membrane type humidifier 23, when the humidification condition is sufficient, that is, the water permeable membrane type humidifier is required for the current operation. When the humidifier 23 alone can handle
The controller ECU stops the water injection valve 26b, and pressurization of the liquid level of the storage part of the condenser 26,
The auxiliary of the humidification by the water injection is stopped (S11).

Therefore, stable power generation of the fuel cell 1 is maintained by the controller ECU.
Voltage is supplied to a load source such as a motor. In the description of the embodiment of the present invention, the condensed water (recovered water) collected by the condenser 26 is sprayed immediately upstream of the cathode electrode gas passage 1a.
May be sprayed downstream of the compressor and upstream of the compressor 24, or both immediately upstream and immediately downstream of the cathode electrode side gas passage 1a. Of course, also in this case, the water spray
It is assumed that the supply air As is supplied until a predetermined dew point or a predetermined humidity required for power generation is reached.

Further, the detection value detected by the monitor CV1 for detecting the voltage or the current value, regardless of the detection by the humidity sensor T1 or the dew point sensor, is the target power generation voltage value or the target power generation value of the fuel cell 1. Until the current value, the water injection valve 26a, and the pressure control valve 25 that pressurizes the liquid level of the reservoir of the condenser 26, or the compressor 28a or a pump is operated to humidify the supply air As. Is also good.

Further, in order to always keep the water level in the reservoir of the condenser 26 at a predetermined level, the liquid level is constantly monitored by the liquid level sensor L1 or the like, and when the output signal from the liquid level sensor L1 is less than the predetermined water level. Is the auxiliary water tank 26
Water is supplied to the condenser 26 from d and the like. Water can be supplied to the condenser 26 until the auxiliary water tank 26d runs out of water. However, in order to protect the fuel cell system 20, the output value of the liquid level sensor L1 is less than a predetermined water level, and humidification by water injection is performed. Is required, the fuel cell system 20 is stopped.

For the condenser 23 and the auxiliary water tank 26d, heaters (not shown) for preventing freezing and sensors T2 and T3 for detecting the temperature of the storage portion of the condenser 26 are provided. Provided by the sensors T2 and T3,
When the temperature of the storage portion of the condenser 26 and the auxiliary water tank 26d is lower than the temperature near the freezing temperature, the heater is operated to prevent freezing.

Further, when the amount of water in the condenser 26 is large, a pump 26h separately attached to the condenser 26
Thus, the increased amount may be transferred to the auxiliary water tank 26d. The condenser 26 may be a condenser (heat exchanger) of a type that obtains condensed water by a heat exchange medium.

Although the compressor 24 has been described as an example of the transfer means of the air transfer passage 2, a pump may be used.

Further, in the embodiment of the present invention, the description has been given of the case where the present invention is applied to the air transfer system. However, similarly to the case of the air transfer system, the humidifying structure according to the present embodiment is provided in the hydrogen transfer passage 2 as fuel gas. (Compressor 24, condenser 26,
Auxiliary water tank 26d, on-off valve 26c, flow control valve 26
g, compressor 28a, etc.) may be applied to improve the performance and reliability of the entire fuel cell.

As described above, the present invention can be variously modified without departing from the gist of the present invention, and the present invention naturally extends to the modified invention.

[0040]

As described in detail in the above embodiment, the invention according to claim 1 is provided with the exhaust gas transfer means on the downstream side of the fuel cell, and on the downstream side of the water permeable membrane type humidifier. In the condensing means for condensing the moisture contained in the exhaust gas, low pressure on the upstream side of the exhaust gas transfer means, high pressure on the downstream side, upstream of the exhaust gas transfer means downstream from the fuel cell, or Since the auxiliary humidifying means for replenishing the water condensed by the condensing means is provided upstream of the fuel cell, it is possible to make the supply gas contain an amount of water necessary for stable power generation of the fuel cell. Generated power can be maintained. In addition, since the operation system has a low pressure loss and a low pressure, the present invention has an extremely large effect, such as improved energy efficiency and improved economic efficiency.

According to the second aspect of the present invention, the amount of water supply is controlled based on at least one of the required humidification amount of the fuel cell and the humidification amount of the water permeable membrane type humidifier.
The supply gas can contain an amount of moisture necessary for stable power generation of the fuel cell, and furthermore, stable power generation can be maintained.

Further, according to the third aspect of the present invention, since the pressure control means is provided downstream of the condensing means for controlling the pressure of the exhaust gas, the pressure on the downstream side (discharge side) of the exhaust gas transfer means is reduced. Even when the pressure is lower than the pressure at which the humidification assisting means is operated, the humidification assisting means can assist the humidification of the supplied gas without using other means, and the reliability can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a fuel cell system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing one embodiment of the present invention and showing one embodiment of control contents of a controller.

FIG. 3 is an explanatory view showing a conventional example and showing a structure of a fuel cell.

FIG. 4 is a configuration diagram showing a conventional example and showing a fuel cell system.

[Explanation of symbols]

 Reference Signs List 1 fuel cell Ae exhaust air He exhaust hydrogen As supply air Hs supply hydrogen 23 water permeable membrane humidifier 24 compressor (exhaust gas transfer means) 25 pressure control valve (pressure control means) 26 condenser (condensation means) 26b injector (auxiliary) Humidifying means)

Continued on the front page (72) Inventor Hiroshi Shimanuki 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 5H026 AA06 5H027 AA06 KK03 KK06

Claims (3)

[Claims] 1. A fuel cell supply gas humidifier having a water permeable membrane humidifier for recovering moisture in exhaust gas discharged from a fuel cell and humidifying a supply gas to the fuel cell. Exhaust gas transfer means provided downstream of the humidifier; condensing means for condensing water contained in the exhaust gas downstream of the water-permeable membrane humidifier; and discharging the water condensed by the condensing means. A supply gas humidifier for a fuel cell, comprising: auxiliary humidification means for supplying the gas to an upstream side of the gas transfer means; 2. The fuel cell supply gas humidifier according to claim 1, wherein the auxiliary humidifier is controlled based on one of a required humidification amount of the fuel cell and a humidification amount of the water-permeable membrane humidifier. apparatus. 3. The supply gas humidifier for a fuel cell according to claim 1, further comprising pressure control means for controlling the pressure of the exhaust gas downstream of the condensation means.