Humidification device for fuel cell and fuel cell system with the same

Abstract

Humidification device (200) for a fuel cell, comprising: a membrane module (110) with bundles of hollow fiber membranes (111) arranged in the membrane module (110); Distributors (120, 130), each connected to both sides of the membrane module (110) and configured to inject a discharged gas from a cathode of the fuel cell and dry air supplied via an air compressor (30) into an inner surface of the membrane module (110) and to discharge the discharged gas, from which moisture has been removed, and the humidifying air from the inner surface of the membrane module (110); and at least one bypass line (150) configured to be inserted into the inner sides of the distributors (120, 130) and connected to the inner side of the membrane module (110), and selectively connected to a supply path of the dry air supplied by the air compressor (30), wherein the humidification device (200) is configured to exchange moisture between the exhaust gas from the cathode of the fuel cell and dry air supplied via the air compressor (30), and to supply the humidified air to the cathode, and wherein the bypass line (150) is fitted with a check valve (155) to prevent a backflow of dry air.

Description

TECHNICAL AREA

[0001] The present invention relates to a fuel cell system of a fuel cell vehicle. In particular, a humidification device for humidifying a reaction gas supplied to the fuel cell is provided. BACKGROUND

[0002] In general, a fuel cell system is a power generation system that produces electrical energy through an electrochemical reaction of hydrogen and oxygen, or oxygen from the air, within a fuel cell. For example, the fuel cell system in a fuel cell vehicle is used to power an electric motor and propel the vehicle. The fuel cell system comprises a stack in which elementary fuel cells, each containing a cathode and an anode, generate electricity; an air supply device provides air to the cathode of the fuel cell; and a hydrogen supply device provides hydrogen to the anode of the fuel cell.

[0003] Meanwhile, a polymer fuel cell requires a significant amount of moisture or humidity for the function of an ion exchange membrane in a membrane electrode assembly (MEA). Consequently, the fuel cell system's air supply includes a humidification device to humidify the air supplied to the fuel cell. The humidification device adds moisture to dry air, supplied to the air supply by an air compressor, by means of air with an elevated temperature or humidity level, which is drawn off from the fuel cell's cathode. The humidified air is then supplied to the fuel cell's cathode.

[0004] Examples of humidification devices can include various types, such as bubbler-type, injection-type, plate-type, absorption-type, membrane-type, and similar designs. Since fuel cell vehicles have limited packing space, membrane-type humidification devices are used with a reduced volume. In particular, membrane-type humidification devices can offer packing advantages, and a separate power source may not be required.

[0005] The membrane-type humidification device, hereinafter referred to as the "membrane humidification device", can use a membrane for humidification by exchanging moisture from one gas to another, such as between exhaust gas with elevated temperature and humidity or moisture from the cathode of the fuel cell and dry air supplied by the air compressor.

[0006] The humidified air produced by the membrane humidification device is supplied to the cathode of the fuel cell, and the exhaust gas, from which moisture has been removed in the membrane humidification device, is released into the air. For example, the membrane humidification device includes a membrane module in which hollow fiber membranes are arranged essentially within a housing having a cylindrical shape, and shell-type distributors formed on both sides of the membrane module.

[0007] According to the related technology, a humidification device structure was supplied, and a portion of the dry air supplied by the air compressor can be sprayed into a discharge path for the exhaust gas. This dilutes the hydrogen in the discharged gas, from which moisture has been removed, from the humidification device into the air. Since hydrogen is present in the discharged gas from the fuel cell vehicle, environmental protection and safety regulations for gas discharge require that the hydrogen in the discharged gas be diluted as described above.

[0008] Consequently, the related technique incorporates a bypass line branching off from an air supply line, connecting the air compressor and humidification device to an exhaust line for the humidification device, and an opening and closing valve for selectively opening or closing a channel of the bypass line. However, because a separate bypass line connects the air supply line and the exhaust line, space may be required to install the bypass line, and an efficient packing arrangement may not be achieved.

[0009] While the membrane humidification device may occupy less volume than other types of humidification devices, a system for exchanging the gas with its moisture content can still require a significant amount of space as a component in a vehicle. In particular, the additional bypass line described above may not be efficient.

[0010] Furthermore, according to the related technique, water condensate can be generated in the membrane humidification device while the device is operating. Since such water condensate can freeze in cold weather conditions, an air duct in the humidification device may be reduced, thereby increasing the load on the air compressor as the pressure rises, and the power consumption of the air compressor may increase, thus reducing the fuel cell vehicle's fuel efficiency.

[0011] Furthermore, if the water condensate in the humidification device freezes under cold operating conditions, the membrane module of the humidification device may be damaged and the humidification performance of the humidification device may be reduced due to the increase in the volume of the water condensate caused by the formation of ice.

[0012] US 2001 / 0 015 500 A1 discloses a humidifier with a plurality of water-permeable hollow fiber membranes arranged along the longitudinal direction of a housing. Gases with varying moisture contents flow inside and outside the hollow fiber membranes. The humidifier includes a bypass channel with a larger diameter than the hollow fiber membrane. Further prior art can be found in DE 11 2004 001 832 T5, US 2001 / 0 010 872 A1, and WO 2004 / 017 450 A2.

[0013] The above information disclosed in this background section is intended solely to improve the understanding of the background of the invention and may therefore contain information that does not constitute the prior art, which would already be known to someone with ordinary technical skills in this country. OVERVIEW

[0014] The object of the present invention is to provide a humidification device for a fuel cell and a fuel cell system. The humidification device can reduce the packing of the fuel cell system and provide substantially improved humidification performance by employing a bypass line in the humidification device.

[0015] The problem is solved by a humidification device with the features of claim 1 and a fuel cell system with the features of claim 8. Advantageous further developments are found in the dependent claims.

[0016] According to the present invention, a humidification device for a fuel cell humidifies exhaust gas from a cathode of the fuel cell and dry air supplied by an air compressor using a membrane. The humidification device is configured to supply humidified air to the cathode.

[0017] The bypass line is installed with a valve located on the outside of the manifold. The membrane module contains a support element that holds both ends of the hollow fiber membrane. The bypass line is attached to the support element. The bypass line is inserted into a lower section of at least one manifold, which carries away the dehumidified gas, and is connected to the inside of the manifold.

[0018] The bypass line can be arranged on an upper section of at least one manifold, which carries away the dehumidified gas, and can be connected to the inside of the manifold. The bypass line can include connecting ports that are connected to the inside of the at least one manifold, which carries away the dehumidified gas. According to another aspect, the bypass line must be installed with a check valve configured to prevent backflow of dry air. The check valve can be a duckbill valve.

[0019] In another exemplary embodiment, a fuel cell system comprises: a stack of a plurality of elementary fuel cells configured to generate electricity; an air compressor configured to supply air to a cathode of the fuel cell; a humidification device connected to the air compressor and configured to humidify exhaust gas from the cathode and dry air supplied by the air compressor using membranes; and a hydrogen tank configured to supply hydrogen to an anode of the fuel cell. In particular, at least one bypass line with an air supply path between the air compressor and the humidification device can be selectively connected and arranged in the humidification device.

[0020] The humidification device comprises the following: a membrane module with bundles of hollow fiber membranes arranged within the membrane module; and manifolds, each of which can be connected to either side of the membrane module, configured to inject the exhaust gas and dry air into one inner surface of the membrane module and to discharge the dehumidified exhaust gas and humidified air from the inner surface of the membrane module. The bypass line is inserted into the inner surfaces of the manifolds and connected to the inner surface of the membrane module, and selectively connected to a dry air supply path provided by the air compressor. The bypass line is further equipped with a duckbill check valve.

[0021] The bypass line can be installed with an opening and closing valve, which can be located on the outside of the manifold.

[0022] Since the bypass line configured to supply air to the humidification device can be located within the humidification device to dilute hydrogen in the exhaust gas from the humidification device, according to various exemplary embodiments of the present invention, the channel in the humidification device can be used as a bypass line space. Therefore, an additional space in which the pipe or hose for the dry air bypass line can be installed is not required, thereby reducing the packing in the fuel cell system.

[0023] Since the bypass line in the section where the water condensate is collected can be arranged in the membrane module and the membrane distributor, according to various exemplary embodiments of the present invention, the water condensate or the collected water in the humidification device can be discharged to the outside, while the dry air is supplied through the bypass line to prevent a pressure increase in the humidification device that occurs due to ice in cold weather conditions.

[0024] Therefore, the load on the air compressor can be reduced due to the pressure increase in the humidification device, consequently lowering the air compressor's power consumption and improving the fuel cell vehicle's fuel efficiency. Furthermore, since the water in the humidification device can be used to humidify the membrane via the airflow through the bypass line, the humidification device's efficiency can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings serve as a reference when describing an exemplary embodiment of the present invention, and the technical scope of the present invention is not to be interpreted as being limited to the accompanying drawings. Fig. Figure 1 schematically shows an exemplary fuel cell system according to an exemplary embodiment of the present invention; Fig. Figure 2 schematically shows an exemplary humidification device for an exemplary fuel cell according to an exemplary embodiment of the present invention; Fig. Figure 3 shows a cross-sectional configuration view of an exemplary humidification device for the fuel cell according to an exemplary embodiment of the present invention; Fig. Figure 4 schematically shows an exemplary check valve of an exemplary bypass line that can be used for an exemplary humidification device for an exemplary fuel cell according to an exemplary embodiment of the present invention; and the Fig. 5, Fig. 6 to Fig. Figure 7 shows schematically modified examples of exemplary bypass lines that can be used for exemplary humidification devices for exemplary fuel cells according to various exemplary embodiments of the present invention.

[0026] The in the Fig. Reference numbers 1-7 contain references to the following elements, which are discussed further below: 10 stacks 30 air compressor 31 Air supply line 50 hydrogen tank 70 Opening and closing valve 110 Membrane module 111 Hollow fiber membrane 113 Housings 115 Support element 120 First distributor 121 First Admission 123 First Exit 130 Second distributor 131 Second Entrance 133 Second outlet 150 bypass line 151 Connecting opening 155 Check valve 157 Admitting 158 Valve passage 159 Omissions 100 fuel cell systems 200 humidification device DETAILED DESCRIPTION

[0027] In the following detailed description, the present invention will be described in more detail below with reference to the accompanying drawings, which show exemplary embodiments of the invention. As anyone with technical expertise will recognize, the described embodiments can be modified in many different ways without deviating from the essence or scope of the present invention. Consequently, the drawings and description are to be considered illustrative and non-limiting. Throughout the description, similar reference numbers denote similar elements.

[0028] Since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily depicted for ease of explanation, the present invention is not necessarily limited to those shown in the drawings, and the thicknesses of various layers and areas are exaggerated for clarity. Furthermore, in the following detailed description, the classification of configuration names as first / first / first, second / second / second, and similar serves to classify the configurations, as the configurations exhibit the same ratio, and the present invention is not necessarily limited to the aforementioned order in the following detailed description.

[0029] The terminology used herein serves only to describe certain embodiments and is not intended to limit the invention. As used herein, the singular forms "a" and "the" shall also include the plural forms unless the context otherwise makes clear. It shall also be clear that the expressions "has" and / or "having" when used in this description specify the presence of the aforementioned features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the expression "and / or" includes any and all combinations of one or more of the associated listed elements.

[0030] It is clear that the term "vehicle" or "vehicle-" or any other similar term used herein includes motor vehicles in general, such as passenger cars, including all-terrain vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft, including a variety of boats and ships, aircraft and the like, and hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other vehicles using alternative fuels (e.g., fuels derived from raw materials other than petroleum). As defined herein, a hybrid vehicle is a vehicle that has two or more power sources, such as both gasoline-powered and electric-powered vehicles.

[0031] Furthermore, a term such as "unit", "facility", "part", "element" or similar, as described in the description, means a unit with a generic configuration for performing at least one function or operation.

[0032] Fig. Figure 1 shows an exemplary fuel cell system according to an exemplary embodiment of the present invention. Fig. 1. A fuel cell system generates 100 electrical energy through an electrochemical reaction of hydrogen as fuel and air as oxidant, and the fuel cell system can be used in a fuel cell vehicle, but the examples are not limited to this.

[0033] The fuel cell system 100 according to the present invention comprises the following: a stack 10, an air compressor 30, a humidification device 200, and a hydrogen tank 50. The stack 10 can contain elementary fuel cells, each having a cathode and an anode configured to generate electricity, and separators referred to as a "separate plate" or "bipolar plate" in related technologies. The separators can be arranged on both sides of each elementary fuel cell, and a membrane electrode assembly is arranged between the separators.

[0034] The fuel cell cathode can be configured to discharge moist air with elevated temperature and humidity, referred to throughout this disclosure as "discharged gas". The fuel cell anode can be configured to discharge moist hydrogen with elevated temperature and humidity as unreacted hydrogen. The air compressor 30 can be configured to supply air to the fuel cell cathode and draw in air from the atmosphere, referred to below as "dry air". The dry air can be compressed and supplied to the humidification device 200 by the air compressor.

[0035] The humidification device 200 according to the present invention is configured for humidification using a membrane by exchanging moisture between gases, such as between the gas discharged from the cathode of the fuel cell and the dry air supplied by the air compressor 30. The humidification device 20 is also configured to supply the humidified air to the cathode of the fuel cell. In particular, the humidification device 200 can be connected to the air compressor 30 via an air supply line 31.

[0036] An exemplary configuration of the humidification device 200 for the fuel cell is described below with regard to the Fig. 2 and Fig. 3 will be described in detail. The hydrogen tank is configured for storing the hydrogen gas and supplying the hydrogen gas to the anode. The stack 10, the air compressor 30, and the hydrogen tank 50, which are generally described in the art, can be used without restriction in the present invention.

[0037] The fuel cell system 100 according to an exemplary embodiment of the present invention, described above, can be configured to supply a portion of the dry air provided by the air compressor 30 to the humidification device 200 in order to dilute the hydrogen in the exhaust gas from the humidification device 200. In particular, a path through which the portion of dry air is supplied to the humidification device 200 can be arranged within the humidification device 200, so that packing in the fuel cell system can be reduced and the humidification efficiency of the humidification device 200 for the fuel cell can be improved.

[0038] The humidification device 200, which is used in the fuel cell system 100 according to exemplary embodiments of the present invention, will below be described in detail with reference to the accompanying drawings.

[0039] Fig. Figure 2 schematically shows an exemplary humidification device for an exemplary fuel cell according to an exemplary embodiment of the present invention and Fig. Figure 3 is a cross-sectional configuration view that schematically shows an exemplary humidification device for a fuel cell according to an exemplary embodiment of the present invention.

[0040] In the Fig. 1, Fig. 2 to Fig. 3 The humidification device 200 for the fuel cell comprises the following: a membrane module 110; first and second distributors 120 and 130; and a bypass line 150. The membrane module 110 has bundles of hollow fiber membranes 111 arranged within it. The membrane module 110 may have the bundle of hollow fiber membrane 111 embedded within a housing 113 having a cylindrical shape, but the exemplary shape of the housing is not limited to this.

[0041] Furthermore, the membrane module 110 can include a support element 115 configured to hold both ends of the hollow fiber membrane 111. The support element 115 can be made of a polymer material and holds the two end sections of the hollow fiber membrane bundle 111, so that it is attached to both ends of the housing 113. The distributors 120 and 130 can be shell-shaped and connected to both ends of the membrane module 110. The distributors 120 and 130 can be configured to inject the exhaust gas from the stack 10 and the dry air supplied by the air compressor 30 into the membrane module 110. Additionally, the distributors 120 and 130 are configured to discharge the humidified air from the membrane humidification unit. In an inner surface of the membrane module 110, moisture is exchanged between the exhaust gas and the dry air, or between the exhaust gas and the exhaust gas from which the moisture has been removed.

[0042] The distributor connected to a first side end section of the membrane module 110 can be called the first distributor 120, and the distributor connected to a second side end section of the membrane module 110 can be called the second distributor 130. The first distributor 120 can form a first inlet 121 for supplying or injecting the exhaust gas from the stack 10 into the membrane module 110 and a first outlet 123 for exhausting the humidified air. Furthermore, the second distributor 130 can form a second inlet 131 for supplying or injecting the dry air supplied by the air compressor 30 into the membrane module 110 and a second outlet 133 for exhausting the dehumidified gas into the atmosphere.

[0043] The first outlet 123 of the first distributor 120 can be connected to the stack 10 via a supply line configured to supply humidified air, and the second inlet 131 of the second distributor 130 can be connected to the air compressor 30 via the air supply line 31. The bypass line 150 can be configured to supply a portion of the dry air supplied by the air compressor 30 to the membrane module 110 via the first and second distributors 120 and 130, thereby diluting hydrogen in the exhaust gas, which is discharged into the atmosphere through the second outlet 133 of the second distributor 130.

[0044] The bypass line 150 can be selectively connected to the air supply line 31, as mentioned above, and can be arranged within the humidification device 200. In particular, the bypass line 150 can be configured to supply the portion of dry air supplied by the air compressor 30 to the membrane module 110 via the inner surfaces of the first and second distributors 120 and 130. For example, the bypass line 150 can branch off from the air supply line 31, be inserted into the first and second distributors 120 and 130, and be connected to the inner surface of the membrane module 110.

[0045] Furthermore, the bypass line 150 can be selectively connected to the air supply line 31, inserted into the second distributor 130, and extended to the first distributor 120. In particular, the bypass line 150 can be inserted into and through the second distributor 130, extended along a longitudinal direction of the membrane module 110, and inserted into the first distributor 120. Additionally, the bypass line 150 can be attached to the support element 115 in the first distributor 120 and be exposed to the outside of the membrane module 110 between the first and second distributors 120 and 130. In particular, an opening and closing valve 70 for selectively opening or closing the bypass line 150 can be installed at a connection point between the air supply line 31 and the bypass line 150. Consequently, the opening and closing valve 70 can be installed on the bypass line 150, which can be an outside of the second distributor 130.The opening and closing valve 70 can be provided as a three-way valve, which can be configured to selectively connect the air supply line 31 and the bypass line 150 according to an electrical signal.

[0046] Meanwhile, connecting openings 151, which are connected to the inside of the second distributor 130, can be formed in the bypass line 150. In particular, the bypass line 150 can be connected to the inside of the diaphragm module 110 via the connecting openings 151 in the inside of the second distributor 130. Furthermore, a check valve 155 can be installed in an airflow path of the bypass line 150 to prevent backflow of the dry air supplied by the air compressor 30. The check valve 155 can be a duckbill check valve, but the examples are not limited to this. The duckbill check valve can include an inlet end 157, into which a fluid can be supplied, and an outlet end 159 with a duckbill shape, from which the fluid can be discharged.For example, the duckbill check valve can have an elastically deformed outlet end 159 with a beak shape and an open valve passage 158 by fluid pressure based on a direction (e.g. fluid supply direction) in which the fluid flows, as in . Fig. 4A shown. As in Fig. As shown in 4B, when the fluid flows back in the opposite direction, the duckbill check valve can have the outlet end 159 with the beak shape that can be returned to an original shape and a closed valve passage 158.

[0047] In another aspect, the operation of the fuel cell system 100 with an exemplary humidification device 200 for an exemplary fuel cell according to an exemplary embodiment of the present invention will be described in detail with reference to the drawings described above. In the present invention, when electrical energy is generated by the electrochemical reaction of hydrogen and air in the fuel cells of the stack 10, the cathodes of the fuel cells discharge the exhaust gas at an elevated temperature and humidity. Subsequently, the exhaust gas can be supplied from the cathode to the membrane module 110 via the first inlet 121 of the first distributor 120. During the aforementioned process, the dry gas supplied via the air compressor 30 can be supplied to the membrane module 110 via the second inlet 131 of the second distributor 130.In particular, the dry air supplied by the air compressor 30 can be fed to the second inlet 131 via the air supply line 31. Furthermore, the opening valve can be configured to open the air supply line 31 and the closing valve to close the bypass line 150, but the opening valve and the closing valve can also be formed as a single, integrated valve.

[0048] Consequently, the membrane module 110 is configured to perform membrane humidification by exchanging moisture between the exhaust gas and the dry air. The humidified air can be discharged via the first outlet 123 of the first distributor 120 and supplied to the cathodes of the fuel cells. Furthermore, the exhaust gas, from which the moisture has been removed on the inside of the membrane module 110, can be discharged to the atmosphere via the second outlet 133 of the second distributor 130.

[0049] Meanwhile, during humidification by the humidification device of the present invention, it may be necessary to dilute the hydrogen in the gas that is discharged to the atmosphere via the second outlet 133 of the second distributor 130. Furthermore, the bypass line 150 can be opened by the opening and closing valve 70. Subsequently, the portion of dry air supplied by the air compressor 30 can be fed to the inner surfaces of the first and second distributors 120 and 130 via the bypass line 150 and to the inner surface of the membrane module 110 via the aforementioned distributors 120 and 130.

[0050] Since the dry air can flow through the bypass line 150 via the inside of the second distributor 130 and be supplied to the inside of the first distributor 120, the dry air can, in particular, be supplied to the inside of the second distributor 130 via the connecting openings 151 of the bypass line 150 in the inside of the second distributor 130. Consequently, the dry air can be supplied to the inside of the membrane module 110 via the first and second distributors 120 and 130. Furthermore, when the dry air is supplied to the insides of the first and second distributors 120 and 130 via the bypass line 150, the backflow of the dry air through the check valve 155 can be prevented. The check valve 155 can have an elastically deformed outlet with a beak shape and an open valve passage by pressure of the dry air based on the direction in which the dry air flows, as shown in Fig. 4A shown, exhibit.

[0051] Furthermore, the check valve 155, as described in Fig. Figure 4B shows that when the dry air flows back in the opposite direction of the flow, the outlet has a beak-shaped design that can be returned to its original form and a closed valve passage, thereby preventing the backflow of dry air. In the fuel cell system 100 according to various exemplary embodiments of the present invention described above, the bypass line 150, which supplies the dry air to the humidification device 200, can be arranged in the humidification device 200 to dilute the hydrogen in the exhaust gas from the humidification device 200.

[0052] Since the bypass line 150, which supplies air to the humidification device 200, is arranged in the humidification device 200 to dilute the hydrogen in the exhausted air from the humidification device 200, the channel in the humidification device 200 can consequently be used as a bypass line space to omit the provision of a space of a pipe or hose for the bypass of the dry air, thereby reducing the packing in the fuel cell.

[0053] The Fig. 5, Fig. 6 to Fig. Figure 7 schematically shows various examples of the bypass line used for the humidification device for the fuel cell according to various exemplary embodiments of the present invention. As in Fig. As shown in Figure 5, an exemplary bypass line 150 can be arranged in a section where water condensate is collected, within the membrane module 110 and the distributors 120 and 130. Since the condensate or collected water in the humidification device 200 can be discharged to the outside, while dry air is supplied via the bypass line 150, an increase in pressure in the humidification device 200 due to ice formation in cold weather conditions can be prevented. Furthermore, the load on the air compressor 30 caused by the pressure increase in the humidification device 200 can be reduced, consequently lowering the power consumption of the air compressor 30 and improving the fuel cell vehicle's fuel efficiency.

[0054] Since the condensate or collected water in the humidification device 200 can be discharged to the outside, while the dry air is supplied via the bypass line 150, the water in the humidification device 200 can also be used to humidify the airflow using a membrane in the humidification device 200, thus further improving the efficiency of the humidification device 200.

[0055] As in Fig. As shown in Figure 6, an exemplary bypass line 150 can be inserted into a lower section of the second distributor 130 and connected to the inside of the second distributor 130. In particular, the bypass line 150 can be connected to the inside of the second distributor 130 because it is inserted into the lower section of the second distributor 130, while it does not penetrate through the lower section of the second distributor 130.

[0056] As in Fig.As shown in Figure 7, an exemplary bypass line 150 can be inserted into an upper section of the second distributor 130 and connected to the inside of the second distributor 130. In particular, the bypass line 150 can be connected to the inside of the second distributor 130 because it is inserted into the upper section of the second distributor 130 but does not penetrate through the upper section of the second distributor 130.

[0057] Although exemplary embodiments of the present invention have been described, it should be noted that the essence of the present invention is not limited to the exemplary embodiments set forth herein, and someone with technical skills who understands the present invention can easily accomplish other exemplary embodiments contained in the essence of the present invention by adding, modifying and removing components within the same essence, but these are designed to be contained in the essence of the present invention.

Claims

[1] Humidification device (200) for a fuel cell, comprising: a membrane module (110) with bundles of hollow fiber membranes (111) arranged in the membrane module (110); Distributors (120, 130), each connected to both sides of the membrane module (110) and configured to inject a discharged gas from a cathode of the fuel cell and dry air supplied via an air compressor (30) into an inner surface of the membrane module (110) and to discharge the discharged gas, from which moisture has been removed, and the humidifying air from the inner surface of the membrane module (110); and at least one bypass line (150) configured to be inserted into the inner sides of the distributors (120, 130) and connected to the inner side of the membrane module (110), and selectively connected to a supply path of the dry air supplied by the air compressor (30), wherein the humidification device (200) is configured to exchange moisture between the exhaust gas from the cathode of the fuel cell and dry air supplied via the air compressor (30), and to supply the humidified air to the cathode, and wherein the bypass line (150) is fitted with a check valve (155) to prevent a backflow of dry air. [2] Humidification device (200) according to claim 1, wherein the bypass line (150) is installed with an opening and closing valve (70) arranged on an outside of the distributor (120, 130). [3] Humidification device (200) according to claim 1, wherein the membrane module (110) includes a support element (115) configured to hold both ends of the hollow fiber membrane (111) and the bypass line (150) is attached to the support element (115). [4] Humidification device (200) according to claim 1, 2 or 3, wherein the bypass line (150) is inserted into a lower section of the at least one distributor (120, 130) configured to discharge the discharged gas from which the moisture has been removed, and is connected to the inside of the distributor (120, 130). [5] Humidification device (200) according to claim 1, wherein the bypass line (150) is arranged on an upper section of the at least one distributor (120, 130) configured to discharge the discharged gas from which the moisture has been removed, and is connected to the inside of the distributor (120, 130). [6] Humidification device (200) according to claim 1, wherein the bypass line (150) is provided with connecting openings (151) which are connected to the inside of the at least one distributor (120, 130) which is configured to discharge the discharged gas from which the moisture has been removed. [7] Humidification device (200) according to claim 1, wherein the check valve (155) is designed by a duckbill valve. [8] Fuel cell system (100), comprising: a stack (10) of elementary fuel cells configured to generate electricity; an air compressor (30) configured to supply air to a cathode of the fuel cell; a humidification device (200) connected to the air compressor (30) and configured to perform membrane humidification of the exhaust gas discharged from the cathode and dry air supplied via the air compressor (30); and a hydrogen tank (50) configured to supply hydrogen to an anode of the fuel cell, wherein at least one bypass line (150) is selectively connected to an air supply path between the air compressor (30) and the humidification device (200) and is configured in the humidification device (200), wherein the humidification device (200) comprises a membrane module (110) with bundles of hollow fiber membranes (111) arranged within the membrane module (110), distributors (120, 130) are each connected to both sides of the membrane module (110) and are configured to inject the exhaust gas and dry air into an inside of the membrane module (110) and to discharge the exhaust gas, from which moisture has been removed, and the humidifying air from the inside of the membrane module (110), wherein the bypass line (150) is inserted into the inner sides of the distributors (120, 130) and is connected to the inner side of the membrane module (110) and is selectively connected to a supply path of the dry air supplied by the air compressor (30), and the bypass line (150) is fitted with a duckbill check valve. [9] Fuel cell system (100) according to claim 8, wherein the bypass line (150) is fitted with an opening and closing valve (70) arranged on an outside of the distributor (120, 130).

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