Humidification unit for fuel cell and fuel cell system with humidification unit

Abstract

Humidification device (200) for a fuel cell (11), which performs membrane humidification of exhaust gas emitted from a cathode (13) of a fuel cell (11) and dry air supplied by an air compressor (30), and supplies humidifying air to the cathode (13), comprising: a main membrane module (210) which includes several bundles of first hollow fiber membranes (211) arranged in the main membrane; and a sub-membrane module (230) which is connected to the main membrane module (210) and includes several bundles of second hollow fiber membranes (231) arranged in the sub-membrane module (230), wherein the sub-membrane module (230) is connected to an air inlet end of the air compressor (30) via a recirculation line (79), and supplies the humidifying air to the air inlet end of the air compressor (30) via the recirculation line (79).

Description

TECHNICAL FIELD

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

[0002] In general, a fuel cell system is a power generation system that generates electrical energy through the electrochemical reaction of hydrogen and oxygen in the air by a fuel cell. For example, the fuel cell system is applied to a fuel cell vehicle to power a vehicle by operating an electric motor.

[0003] The fuel cell system includes a stack formed of an electricity generation assembly of fuel cell units composed of a cathode and an anode, an air supply device for supplying air to the cathode of the fuel cell, and a hydrogen supply device for supplying hydrogen to the anode of the fuel cell.

[0004] Meanwhile, in a polymer fuel cell, appropriate humidity is provided so that an ion exchange membrane of a membrane electrode assembly (EEA) can operate smoothly. As such, the air supply device of the fuel cell system includes a humidifier for humidifying the air supplied to the fuel cell.

[0005] For example, the humidification device humidifies dry air supplied by an air compressor to the air supply device by using moisture in highly heated and highly humid air discharged from the cathode of the fuel cell, and supplies the humidified air to the cathode of the fuel cell.

[0006] As for the humidifier, various types of humidifiers have been developed, such as bubble-type humidifiers, injection-type humidifiers, plate-type humidifiers, adsorption-type humidifiers, and membrane-type humidifiers, among others. However, the membrane-type humidifier, which has a reduced volume, has been applied to fuel cells used in vehicles because space is limited. The membrane-type humidifier described above has the advantage of not requiring special power, as well as the advantage of size.

[0007] In the membrane type humidifier (hereinafter referred to as membrane humidifier), humidification is carried out by exchanging moisture between gases, such as between highly heated and highly humid exhaust gas discharged from the cathode of the fuel cell and dry air supplied via the air compressor.

[0008] However, the membrane-type humidifier has a reduced volume compared to other types of humidifiers, but during the exchange of moisture between gas and gas, the membrane humidifier may have a substantial volume as a vehicle component, whereby the membrane humidifier may be disadvantageous in packaging.

[0009] Furthermore, water may be condensed in the humidifier due to the functional characteristics of the membrane humidifier according to the related art. Since the condensed water may freeze in cold weather conditions as described above, an air passage in the humidifier may certainly shrink, so that a load on the air compressor may increase due to an increase in pressure, and therefore, the power consumption of the air compressor may increase. As a result, the fuel efficiency of the fuel cell vehicle may deteriorate.

[0010] Furthermore, when the condensed water in the humidifier freezes under cold weather conditions, a membrane module of the humidifier may be damaged by a volume expansion of the frozen condensed water, and the humidification performance of the humidifier may be deteriorated.

[0011] Meanwhile, a temperature of air compressed by an air compressor rises to about 100–150°C at the time of power operation of the stack due to the compression ratio and a considerable amount of air.

[0012] Since the temperature of the compressed air, as described above, is higher than the normal operating temperature of the stack of approximately 60–80°C, the temperature acts as a detrimental condition to the humidification efficiency of the humidifier and the operating efficiency of the stack. The elevated temperature of the compressed air supplied to the humidifier by the air compressor must be reduced in the fuel cell system.

[0013] Furthermore, in a turbo-type air compressor that rotates at high speed, the cooling of a motor that rotates a propeller and a bearing that supports a rotating shaft of the motor can become important design factors that determine the performance and lifetime of the entire device.

[0014] In particular, if the heat generated in a motor's coil winding and magnet is not properly cooled, the coil may be damaged or the insulation may deteriorate. Furthermore, if a rare earth element-based magnet is used in the motor, cooling the magnet may also be important, as the magnet may deteriorate due to high-temperature demagnetization.

[0015] Additionally, the bearing is used to support the rotating shaft of the air compressor motor. Although different types of bearings have different temperature ranges, the appropriate temperature can be determined according to the type or material of the bearing, and the bearing must also be appropriately cooled.

[0016] As such, according to the related art, an intercooler, a water pump, and the like are installed in an air supply path connecting the air compressor and the humidifier, as an example of a cooling unit for cooling air supplied from the air compressor.

[0017] However, according to the related art, cooling units such as an intercooler, a water pump and / or the like are additionally installed for cooling the air compressed by the air compressor, such as the air supply device for supplying air to the stack, which is disadvantageous in terms of packaging of the entire fuel cell system.

[0018] The above information disclosed in this Background section is only to enhance the understanding of the background of the invention, and may therefore contain information which does not constitute prior art which is already known to a person of ordinary skill in the art in this country. SUMMARY OF THE INVENTION

[0019] The present invention provides a humidification device for a fuel cell which can separately circulate humidified humidification air to an air inlet end of an air compressor and humidification air supplied to the cathodes of the fuel cells.

[0020] In addition, the present invention provides a fuel cell system that can circulate separately humidified humidification air to an air inlet end of an air compressor to cool the air compressor in an air supply system, thereby improving humidification performance.

[0021] In an exemplary embodiment of the present invention, a humidification device for a fuel cell is provided, which performs membrane humidification of exhaust gas discharged from a cathode of the fuel cell and dry air supplied by an air compressor, and further supplies the humidification air to the cathode. The humidification device may include: a main membrane module including several bundles of first hollow fiber membranes arranged in the main membrane; and a sub-membrane module connected to the main membrane module and including several bundles of second hollow fiber membranes arranged or concentrated in the sub-membrane module.

[0022] The humidification device for a fuel cell according to an exemplary embodiment of the present invention can supply humidification air discharged from the main membrane module to the cathode of the fuel cell.

[0023] The humidification device for a fuel cell according to an exemplary embodiment of the present invention can supply humidification air discharged from the sub-membrane module to the air inlet end of the air compressor.

[0024] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the sub-membrane module may be connected to an air inlet end of the compressor via a circulation line, and may supply the humidification air to the air inlet end of the air compressor via the circulation line.

[0025] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the sub-membrane module may be connected to a dry air supply line for supplying the dry air to the main membrane module, but may also be connected to an air outlet end of the air compressor via a branch line branched from the dry air supply line.

[0026] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the main membrane module and the sub-membrane module may be provided integrally with each other in a single housing.

[0027] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the main membrane module and the sub-membrane module may be separated from each other by a partition wall in the housing.

[0028] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the casing may include: a first inlet part through which the dry air supplied by the air compressor is introduced into the main membrane module; a second inlet part through which a portion of the dry air supplied by the air compressor into the sub-membrane module is introduced; a third inlet part through which the exhaust gas discharged from the cathode of the fuel cell is guided into the main membrane module; a fourth inlet part formed in the partition wall, connecting the main membrane module and the sub-membrane module, and introducing the exhaust gas into the sub-membrane module; a first exhaust part that discharges the humidification air humidified in the main membrane module; a second exhaust part that discharges the humidification air humidified in the sub-membrane module;and a third exhaust part which discharges the exhaust gas in which the moisture has been removed while the exhaust gas passes from the main membrane module through the sub-membrane module;

[0029] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the first influencing part may be connected to an air outlet end of the air compressor via a dry air supply line.

[0030] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the second inflow part may be connected to the air outlet end of the air compressor via a branch line branching from the dry air supply line.

[0031] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the second exhaust part may be connected to an air inlet end of the air compressor via a circulation line.

[0032] In the humidification device for a fuel cell according to an exemplary embodiment of the present invention, the fourth influencing part may be formed by a communication hole connecting the main membrane module and the sub-membrane module.

[0033] In another aspect, the present invention provides a fuel cell system which may include: a stack formed of an electricity-generating assembly of fuel cell units; an air compressor for supplying air to a cathode of a fuel cell; a humidifier connected to the air compressor and performing membrane humidification of the exhaust gas discharged from the cathode and the dry air supplied by the air compressor; and a hydrogen tank for supplying hydrogen to an anode of the fuel cell.In particular, the humidification device may include: a main membrane module including some bundles of first hollow fiber membranes arranged in the main membrane module, and a sub-membrane module connected to the main membrane module and some bundles of second hollow fiber membranes arranged or concentrated in the sub-membrane module.

[0034] In the fuel cell system according to an exemplary embodiment of the present invention, humidification air discharged from the sub-membrane module may be supplied into an air inlet end of the air compressor via a circulation line, and dry air compressed in the air compressor may be cooled by the humidification air.

[0035] In the fuel cell system according to an exemplary embodiment of the present invention, the humidifying device may supply the dry air supplied from the air compressor to the main membrane module through a dry air supply line.

[0036] In the fuel cell system according to an exemplary embodiment of the present invention, the humidifying device may supply a part of the dry air to the sub-membrane module through a branch line branching from the dry air supply line.

[0037] In the fuel cell system according to an exemplary embodiment of the present invention, the humidifying device may supply the humidifying air discharged from the main membrane module to the cathode of the fuel cell through a humidifying air supply line.

[0038] In the fuel cell system according to an exemplary embodiment of the present invention, the humidifying device may supply the humidifying air discharged from the sub-membrane module to an air inlet end of the air compressor via a circulation line.

[0039] In the fuel cell system according to an exemplary embodiment of the present invention, the main membrane module and the sub-membrane module may be provided integrally in a single casing and separated from each other by a partition wall in the casing.

[0040] In the fuel cell system according to an exemplary embodiment of the present invention, the casing may include: a first inlet part for introducing the dry air supplied by the air compressor into the main membrane module; a second inlet part for introducing a portion of the dry air supplied by the air compressor into the sub-membrane module; a third inlet part for introducing the exhaust gas discharged from the cathode of the fuel cell into the main membrane module; a fourth inlet part formed in the partition wall, connecting the main membrane module and the sub-membrane module, and introducing the exhaust gas into the sub-membrane module; a first exhaust part for discharging the humidification air humidified in the main membrane module; a second exhaust part for discharging the humidification air humidified in the sub-membrane module.a third exhaust part which discharges exhaust gas in which the moisture has been removed as the exhaust gas passes from the main membrane module through the sub-membrane module;

[0041] In the fuel cell system according to an exemplary embodiment of the present invention, the first inflow part may be connected to an air outlet end of the air compressor via a dry air supply line.

[0042] In the fuel cell system according to an exemplary embodiment of the present invention, the second inflow member may be connected to the air outlet end of the air compressor via a branch line branching from the dry air supply line.

[0043] In the fuel cell system according to an exemplary embodiment of the present invention, the third inflow member may be connected to the cathode of the fuel cell via an air outlet pipe.

[0044] In the fuel cell system according to an exemplary embodiment of the present invention, the first influencing part may be connected to the cathode of the fuel cell via a humidifying air supply line.

[0045] In the fuel cell system according to an exemplary embodiment of the present invention, the second exhaust part may be connected to an air inlet end of the air compressor via a circulation line.

[0046] Preferred vehicles of the present invention may include the fuel cell system as described herein.

[0047] According to various exemplary embodiments of the present invention, since the humidification air discharged from the sub-membrane module is circulated to the air inlet end of the air compressor, a temperature of compressed air in the air compressor can be reduced, and configuration components of the air compressor can be cooled by the compressed air whose temperature is cooled, thereby improving the aerodynamic performance and efficiency of the air compressor.

[0048] In addition, according to various embodiments of the present invention, since the humidification air discharged from the sub-membrane module is circulated to the air inlet end of the air compressor, a relative humidity of the air supplied to the humidifier can increase, so that a load of the humidifier can be reduced, the humidification efficiency of the humidifier can be improved, and a size of the humidifier can be reduced.

[0049] In addition, according to various exemplary embodiments of the present invention, since the air compressor is cooled by circulating the humidification air discharged from the sub-membrane module to the air inlet end of the air compressor, a separate cooling unit such as an intercooler, a water pump, and the like as in the related art can be omitted, and the size of the humidifier can be decreased by increasing the relative humidity of the air supplied to the humidifier, thereby reducing the packaging of the entire fuel cell system. SHORT DESCRIPTION OF THE CHARACTERS

[0050] The accompanying figures are provided to describe exemplary embodiments of the present invention, so that the technical idea of ​​the present invention is not limited to the accompanying figures.

[0051] Fig. 1 shows an exemplary fuel cell system according to an exemplary embodiment of the present invention.

[0052] Fig. 2 is a sectional view schematically illustrating an exemplary humidification device for an exemplary fuel cell according to an exemplary embodiment of the present invention.

[0053] Fig. 3 shows an exemplary operation of the fuel cell system according to an exemplary embodiment of the present invention.

[0054] Fig. 4 and Fig. 5 show comparative examples for describing an exemplary operating effect of an exemplary fuel cell system according to an exemplary embodiment of the present invention.

[0055] Reference symbols used in the Fig. 1 to Fig. 5 include reference to the following elements, as discussed below: List of reference symbols 10 stacks 11 Fuel cell 12 Membrane electrode arrangement 13 Cathode 15 Anode 30 air compressor 50 hydrogen tanks 71 Air supply line 73 branch line 75 exhaust pipe 77 Humidification air supply line 79 Circulation line 100 fuel cell system 110 housings 115 Partition wall 131 first part of influence 132 second part of influence 133 third part of influence 134 fourth part of influence 136 connecting hole 151 first exhaust part 152 second exhaust part 153 third exhaust part 200 humidification device 210 Main membrane module 211 first hollow fiber membrane 230 sub-membrane module 231 second hollow fiber membrane EXACT DESCRIPTION

[0056] The present invention will now be described in more detail with reference to the accompanying figures, in which exemplary embodiments of the present invention are shown so that those skilled in the art can easily apply the present invention. Those skilled in the art will appreciate that the described embodiments can be modified in various ways without departing from the spirit and scope of the present invention.

[0057] In order to clarify the present invention, parts not related to the description are omitted, and like elements or equivalents are designated by like reference numerals throughout the specification.

[0058] The size and thickness of each element are schematically shown in the figures for convenience of explanation, however, the present invention is not necessarily limited thereto, and in the figures, the thickness of the parts, regions, etc. are enlarged for clarity.

[0059] Furthermore, the use of the terms first, second, etc. is used to distinguish one element from another and is not limited to the order of the following description.

[0060] In addition, unless expressly stated to the contrary, the words "comprise" and variations such as "comprises" or "comprising" are understood to imply the presence of the stated elements, but not the absence of other elements.

[0061] Furthermore, the terms “unit”, “means”, “-er”, “component”, etc., described in this specification represent a design unit for performing at least one function or actuation.

[0062] Fig. 1 shows an exemplary fuel cell system according to an exemplary embodiment of the present disclosure.

[0063] As shown in Fig. 1 generates the fuel cell system 100 According to an exemplary embodiment of the present invention, electrical energy is generated by the electrochemical reaction of hydrogen as fuel and air as oxidant. The fuel cell system 100 may be included in a fuel cell vehicle, but is not limited to this.

[0064] The fuel cell system 100 according to an exemplary embodiment of the present invention includes a stack 10 , an air compressor30 , a humidification device 200 , and a hydrogen tank 500 , and each of the components is described below.

[0065] The stack is formed from an electricity-generating arrangement of fuel cell units, in which a cathode 13 and an anode 15 and a separator, also referred to as a “separator plate” or “bipolar plate” in the art, on both sides of the membrane electrode assembly (MEA) 12 are arranged.

[0066] In the cathodes 13 the fuel cells 11 Highly heated and highly humid air (hereinafter also referred to as “exhaust gas”) is discharged, and in the anodes 15 The fuel cells release highly heated and highly humid hydrogen as unreacted hydrogen.

[0067] The air compressor 30 which supplies air to the cathodes 13 the fuel cells 11sucks oxygen in the air (hereinafter also referred to as “dry air”), and compresses the dry air to supply the compressed air to a humidification device 100 which is described below.

[0068] Since the air compressor 30 Dry air with a high compression ratio and high energy output of the stack 10 compressed, the temperature of the compressed air may rise, which may have a negative impact on the humidification efficiency of the humidification device 200 and the operating efficiency of the stack 10 Furthermore, heat may be generated in design components such as a compression member, a drive motor, a bearing, and the like.

[0069] In the humidification system 200 According to an exemplary embodiment of the present invention, membrane humidification of the exhaust gas discharged from the cathodes13 the fuel cells 11 , and the dry air supplied by the air compressor 300 , carried out by exchanging moisture between gas and gas, and the humidified air (hereinafter referred to as “humidifying air”) can be supplied to the cathodes 13 the fuel cells 11 In particular, the humidification device 200 be connected to the air compressor 30 through a dry air supply line 71 .

[0070] A detailed description of a design of the humidification device 200 for a fuel cell according to an exemplary embodiment of the present invention is described below with reference to Fig. 2 provided.

[0071] The hydrogen tank 30 which hydrogen to the anodes 15 the fuel cells 11can store hydrogen and supply hydrogen to the anodes 15 lead.

[0072] Since configurations of the stack 10 , the air compressor 30 and the hydrogen tank 50 as described above are generally known in the art, a detailed description thereof is omitted from the present specification.

[0073] In the fuel cell system 100 According to an exemplary embodiment of the present invention, the humidification device 200 for a fuel cell capable of separately supplying the humidified humidification air to an air inlet end of the air compressor 300 to circulate and the humidification air to the cathodes 13 the fuel cells 11 to deliver, be made available.

[0074] In addition, the humidification device 200for a fuel cell capable of separately circulating the humidification air to the air inlet end of the air compressor 300 to the air compressor 30 in an air supply system, and improves the humidification performance, and the fuel cell system 100 , which the humidification device 200 can also be made available.

[0075] Hereafter, a design of the humidification device 200 which is applied to a fuel cell according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0076] Fig. 2 is a sectional view illustrating an exemplary humidifying device for an exemplary fuel cell according to an exemplary embodiment of the present invention.

[0077] As shown in the Fig. 1 and Fig. 2 the humidification device 200 for a fuel cell according to an exemplary embodiment of the present invention, a housing 110 and a main membrane module 210 and a sub-membrane module 230 which are integrally connected to one another in the housing 110 are provided, and each of the embodiments is described below.

[0078] According to an exemplary embodiment of the present invention, in the housing 110 a main membrane module 210 and a sub-membrane module 230 be provided integrally with each other, and the housing 110 may be, but is not limited to, a single housing or a housing which is partitioned into two or more parts to form the main membrane module 210 and the sub-membrane module 230 to wear.

[0079] The housing 110 can also accommodate various additional components to support the main membrane module 210 and the sub-membrane module 230 such as various brackets, blocks, projections, ribs, sleeves and the like.

[0080] However, the above-mentioned various additional components are summarized in the exemplary embodiment of the present invention as the housing 110 except for a special case, since the above mentioned various additional components are provided to the main membrane module 210 and the sub-membrane module 230 in the housing 110 which are described further below.

[0081] According to an exemplary embodiment of the present invention, in the main membrane module 210Membrane humidification can be carried out by exchanging moisture between gas and gas, such as exhaust gas, which is released from the cathodes 13 the fuel cells and the dry air, which was supplied by the air compressor 30 was supplied.

[0082] The main membrane module 210 can discharge the humidification air obtained by membrane humidification through moisture exchange between the exhaust gas and the dry air, and can discharge the humidification air to the cathode 13 the fuel cells 11 supply.

[0083] The main membrane module 210 can be some bundles of first hollow fiber membranes 211 which are tightly sealed in the housing 110 In particular, the main membrane module 210 in the housing 110 be fixed by a support unit which is made of a polymer material.

[0084] According to an exemplary embodiment of the present invention, membrane humidification in the sub-membrane module 230 separate from the main membrane module 210 carried out by exchanging moisture between the exhaust gas, which is emitted by the cathodes 13 the fuel cells and the dry air, which was supplied by the air compressor 30 was supplied.

[0085] The sub-membrane module 230 can discharge separated humidification air obtained by membrane humidification through moisture exchange between the exhaust gas and the dry air, and can discharge the humidification air to the air inlet end of the air compressor 30 lead.

[0086] The sub-membrane module 230 can be connected to the main membrane module 210 in the housing 110 , and can contain some bundles of second hollow fiber membranes 231 which are tightly sealed in the housing 110In particular, the sub-membrane module 230 be fixed in the housing 110 by a carrying unit made of polymer material.

[0087] The main membrane module 210 and the sub-membrane module 230 According to an exemplary embodiment of the present invention, as described above, can be integrally connected to one another in the housing 110 be provided.

[0088] Furthermore, the main membrane module 210 and the sub-membrane module 230 according to an exemplary embodiment of the present invention partitioned in the housing 110 be provided to be separated by a partition 115 to be.

[0089] In the housing 110 As described above, a distributor can direct the exhaust gas emitted from the cathodes 13 the fuel cells 11, and the dry air supplied by the air compressor 20 , the main membrane module 210 and the sub-membrane module 120 The distributor can also deliver the humidification air obtained by membrane humidification through moisture exchange between the exhaust gas and the dry air in the main membrane module 210 and the sub-membrane module 230 , and further release gas to the outside in which the moisture has been removed.

[0090] In particular, the housing 110 include: a first part of influence 131 for introducing the dry air, which is produced by the air compressor 30 into the main membrane module 210 was delivered; a second connecting part 132 to introduce a part of the dry air which is produced by the air compressor 30 was fed into the sub-membrane module 230 ; and a third part of influence 133for introducing the exhaust gas, which is emitted by the cathodes 13 the fuel cells 11 was released into the main membrane module 210 .

[0091] In addition, a fourth part of influence 134 as a connecting hole 136 , which is the main membrane module 210 and the sub-membrane module 230 connects each other, be formed in the partition wall 115 which the main membrane module 210 and the sub-membrane module 230 in the housing 110 separates from each other.

[0092] The fourth part of influence 134 As described above, the exhaust gas introduced into the main membrane module through the third inflow part 133 , into the submembrane module 230 through the connecting hole 136 introduce.

[0093] In addition, the housing 110 further comprising: a first exhaust part 151for discharging the humidification air which is stored in the main membrane module 210 was humidified; a second exhaust part 152 for releasing the humidification air which is stored in the sub-membrane module 230 was humidified; and a third exhaust part 153 to release gas in which moisture has been removed while the gas passes through the sub-membrane module 220 from the main membrane module 210 runs.

[0094] In the housing 110 , as described above, the first part of influence 130 be connected to an air outlet end of the air compressor 30 through a dry air supply line 71 . Consequently, the main membrane module 210 be connected to the air outlet end of the air compressor 30 through the first part of influence 131 and the dry air supply line 71 As such, the dry air supplied by the air compressor 30was delivered to the main membrane module 210 through the dry air supply line 71 supplied according to an exemplary embodiment of the present invention.

[0095] The second part of influence 132 can be connected to the air outlet end of the air compressor 30 through a branch line 73 which extends from the dry air supply line 71 Consequently, the submembrane module 230 be connected to the dry air supply line 71 through the second part of influence 132 and the branch line 73 , and be connected to the air outlet end of the air compressor 30 through the dry air supply line 71 . As such, a portion of the dry air according to the exemplary embodiment of the present invention may be supplied to the sub-membrane module 230 through the branch line 73which extends from the dry air supply line 71 branches off during a process of supplying the dry air from the air compressor 30 via the dry air supply line 71 .

[0096] The third part of influence 133 can be connected to the cathodes 13 the fuel cells 11 through the air discharge line 75 . Consequently, the main membrane module 210 be connected to the cathodes 13 the fuel cells 11 about the third part of influence 133 and the air discharge line 75 As such, according to an exemplary embodiment of the present invention, the highly heated and highly humid exhaust gas emitted by the cathodes 13 the fuel cells 11 was delivered, fed to the main membrane module 210 via the air discharge line 75 .

[0097] The fourth part of influence 134, which as described above in the partition wall 115 The main membrane module can 210 and the sub-membrane module 230 connect with each other, and the exhaust gas which was introduced into the main membrane module 210 through the third part of influence 133 , into the submembrane module 230 introduce.

[0098] The first exhaust part 151 can be connected to the cathodes 13 the fuel cells 11 via a humidification air supply line 77 . Consequently, the main membrane module 210 be connected to the cathodes 13 the fuel cells 11 via the first exhaust part 151 and the humidification air supply line 77 As such, according to an exemplary embodiment of the present invention, the humidification air passing through the first exhaust line of the main membrane module 210was released, fed to the cathodes 13 the fuel cells 11 via the humidification air supply line 77 .

[0099] The second exhaust part 152 can be connected to the air inlet end of the air compressor 30 via a circulation line 79 . Consequently, the sub-membrane module 230 be connected to the air inlet end of the air compressor 30 via the second exhaust part 152 and the circulation line 79 As such, according to an exemplary embodiment of the present invention, the humidification air discharged through the second exhaust part 252 of the sub-membrane module 230 , supplied or circulated to the air inlet end of the air compressor 30 via the circulation line 79 , and therefore the dry air which is compressed in the air compressor 30, are cooled by the humidified air.

[0100] In addition, the third exhaust part 153 , which leads to the sub-membrane module 230 connected to the exhaust gas in which the moisture has been removed while the exhaust gas passes through the sub-membrane module 230 from the main membrane module 210 to the outside or to the air.

[0101] After this, the work steps of the humidification device 200 for a fuel cell according to an exemplary embodiment of the present invention, which is designed as described above, and the fuel cell system 100 having the same will be described in detail with reference to the above figures and the attached figures.

[0102] Fig. 3 shows an exemplary operation of an exemplary fuel cell system according to an exemplary embodiment of the present invention.

[0103] As shown in Fig. 3 can, according to an exemplary embodiment of the present invention, during a process of generating electrical energy as an electrochemical reaction of hydrogen and air by the fuel cells 11 of the stack 10 Highly heated and highly humid exhaust gas is emitted by the cathodes 13 the fuel cells 11 .

[0104] Thereafter, according to an exemplary embodiment of the present invention, the exhaust gas emitted from the cathodes 13 the fuel cells 11 was delivered, fed to the main membrane module 210 through the air discharge line 75 and the third part of influence 133 .

[0105] According to an exemplary embodiment of the present invention, during this process, the dry air supplied by the air compressor 30, are fed to the main membrane module 210 through the dry air supply line 71 and the first part of influence 131 .

[0106] Here, according to an exemplary embodiment of the present invention, a process of supplying the dry air supplied from the air compressor 30 to the main membrane module 210 via the dry air supply line 71 , a part of the dry air is supplied to the sub-membrane module 230 through the branch line 73 , which branches off from the dry air supply line 71 and the second part of influence 132 .

[0107] According to various exemplary embodiments of the present invention, membrane humidification may be performed by exchanging moisture between gas and gas, or alternatively by exchanging moisture between the exhaust gas and the dry air in the main membrane module 210 . The humidification air can subsequently be discharged to the first exhaust part 151 In particular, the humidification air can be supplied to the cathodes 13 the fuel cells 11 through the humidification air supply line 77 .

[0108] During the above processes, the exhaust gas passing through the main membrane module 210 runs, are fed to the sub-membrane module 230 in a moisture-containing state by the fourth part of influence 134 .

[0109] As such, membrane humidification can be carried out by exchanging moisture between the exhaust gas and the dry air in the sub-membrane module 230 , and the humidification air can be discharged via the second exhaust part 152 .

[0110] Subsequently, according to an exemplary embodiment of the present invention, the humidification air passing through the second exhaust part 152 discharged, as described above, are circulated to the air inlet end of the air compressor 30 via the circulation line 79 .

[0111] Consequently, the humidification air containing moisture can be introduced into the air compressor 30 by circulation of the humidification air, which is supplied from the sub-membrane module 230 was delivered to the air inlet end of the air compressor 30 .

[0112] As a consequence, according to an exemplary embodiment of the present invention, the temperature of the air which is in the air compressor 30 compressed, and configuration components of the air compressor 30 , such as a compression part, a drive motor, a bearing and the like can be cooled by the compressed air, whose temperature is cooled, thereby improving the aerodynamic performance and the efficiency of the air compressor 30 be improved.

[0113] Furthermore, according to an exemplary embodiment of the present invention, the relative humidity of the air supplied to the humidifying device 200 , so that a load on the humidification system 200 can be reduced, and the humidification performance of the humidification device 200 can be increased, and the size of the humidification device 200can also be reduced, since the humidification air, which is supplied by the sub-membrane module 230 was delivered to the air inlet end of the air compressor 30 is circulated.

[0114] Meanwhile, as described above, the exhaust gas passing through the main membrane module 210 and the sub-membrane module 230 passes, are released to the air through the third exhaust part 153 in a state in which moisture has been removed.

[0115] In the humidification system 200 for a fuel cell according to an exemplary embodiment of the present invention and the fuel cell system 100 , which the humidification device 200as described above, a separate cooling unit such as an intercooler and a water pump as in the related art can be omitted by cooling the temperature of the air which has been compressed in the air compressor 30 , and by the circulation of humidification air, which is supplied from the sub-membrane module 230 was delivered to the air inlet end of the air compressor 30 .

[0116] In addition, according to an exemplary embodiment of the present invention, a delay in a cooling start timing for raising a temperature of a coolant of the intercooler in winter can be prevented, and therefore a cold start time of the fuel cell system can be shortened because the cooling unit such as the intercooler is omitted.

[0117] In addition, a predetermined amount of air can be recirculated to the air compressor 30through the sub-membrane module 230 during high power operation of the stack 10 , causing a jump wave of the air compressor 30 is prevented according to an exemplary embodiment of the present invention. As such, the air compressor can be operated stably.

[0118] Furthermore, according to an exemplary embodiment of the present invention, condensed water collected from a lower end of the humidifying device 200 , be removed and used by moistening the sub-membrane module 230 , since the sub-membrane module 230 below the main membrane module 210 is made available.

[0119] Furthermore, according to an exemplary embodiment of the present invention, since a separate cooling unit such as an intercooler, the water pump and the like as used in the related art can be omitted and the size of the humidifying device 200 can be reduced, thereby reducing the size of the entire fuel cell system 100 can be reduced.

[0120] In addition, according to an exemplary embodiment of the present invention, since a separate cooling unit such as the intercooler, the water pump, and the like used in the related art can be omitted, various components provided in this cooling unit such as valves, nozzles, and the like are not needed, so that damage to these components caused by freezing of water at low temperature can be prevented.

[0121] Hereinafter, comparative examples are described in comparison with the humidification device 200 for a fuel cell according to an exemplary embodiment of the present invention and the fuel cell system 100 which has the same.

[0122] Fig. 4 and Fig. 5 show comparative examples for describing an operating effect of the fuel cell system according to an exemplary embodiment of the present invention.

[0123] As shown in Fig. 4, in a first comparative example compared with an exemplary embodiment of the present invention, a part of the humidification air can be circulated to an air inlet end of the air compressor 5 as shown by a dashed line during a process of supplying exhaust gas discharged from a stack 1 to a humidification device 3, a supply of dry air, which was supplied by an air compressor 5 to the humidification device 3 , and supplying humidifying air which was emitted by the humidification device 3 to the stack 1 .

[0124] In the first comparative example as described above, the cooling unit such as the intercooler as in the related art may be omitted, but condensate water in the humidifying device 3 not be removed and used. In addition, the temperature of the humidification air may be high, so that the cooling effect of the air compressor 5 is worse than compared to an exemplary embodiment of the present invention.

[0125] In Fig.5 can be seen in a second comparative example compared to an exemplary embodiment of the present invention during a process of supplying exhaust gas which is supplied from a stack 1 was released to a humidification device 3 , the supply of dry air, which was supplied by the air compressor 5 , to the humidification device 3 , and the supply of humidifying air, which is supplied by the humidification device 3 was submitted to the stack 1 the exhaust gas emitted by the humidification device 3 in a state in which moisture has been removed, be circulated to an air inlet end of the air compressor 5 , as shown by a dashed line.

[0126] Since in the second comparative example as described above, the cooling unit such as the intercooler and the like as in the prior art can be omitted, however, since a nitrogen concentration in the exhaust gas is high, a nitrogen concentration in the air stored in the stack 1 is introduced, so that the performance of the stack 1 may be worse than compared to an exemplary embodiment of the present invention.

[0127] Although various exemplary embodiments of the present invention have been described, the spirit of the present invention is not limited to the embodiments presented here, and those skilled in the art who understand the present invention can easily effect other embodiments that are within the spirit of the present invention by additions, modifications, and deletion of components in the same spirit, however, these should be considered to be included within the spirit of the present invention.

Claims

[1] A humidification device for a fuel cell, which performs membrane humidification of exhaust gas discharged from a cathode of a fuel cell and dry air supplied by an air compressor, and supplies humidification air to the cathode, comprising: a main membrane module including several bundles of first hollow fiber membranes arranged in the main membrane; and a sub-membrane module connected to the main membrane module and including several bundles of second hollow fiber membranes arranged in the sub-membrane module. [2] A humidifying device for a fuel cell according to claim 1, wherein the humidifying air discharged from the main membrane module is supplied to the cathode of the fuel cell, and the humidifying air discharged from the sub-membrane module is supplied to an air inlet end of the air compressor. [3] The humidification device for a fuel cell according to claim 1, wherein the sub-membrane module is connected to an air inlet end of the air compressor via a circulation line, and supplies the humidification air to the air inlet end of the air compressor via the circulation line. [4] A humidifying device for a fuel cell according to claim 3, wherein the sub-membrane module is connected to a dry air supply line for supplying the dried air compressed in the air compressor to the main membrane module, but is connected to an air outlet end of the air compressor via a branch line branched from the dry air supply line. [5] A humidifying device for a fuel cell according to claim 1, wherein the main membrane module and the sub-membrane module are provided integrally with each other in a single housing. [6] A humidifying device for a fuel cell according to claim 5, wherein the main membrane module and the sub-membrane module are separated from each other by a partition wall in the housing. [7] A humidifying device for a fuel cell according to claim 6, wherein the housing includes: a first inlet part which introduces the dry air supplied by the air compressor into the main membrane module; a second inlet part which introduces a part of the dry air supplied by the air compressor into the sub-membrane module; a third inlet part through which the exhaust gas discharged from the cathode of the fuel cell is introduced into the main membrane module; a fourth inflow part formed in the partition wall, connecting the main membrane module and the sub-membrane module, and introducing exhaust gas into the sub-membrane module; a first exhaust part which discharges the humidification air humidified in the main membrane module; a second exhaust part which discharges the humidification air humidified in the sub-membrane module; and a third exhaust part which discharges the exhaust gas in which moisture has been removed as the exhaust gas passes through the sub-membrane module from the main membrane module. [8] A humidifying device for a fuel cell according to claim 7, wherein the first inflow part is connected to an air outlet end of the air compressor via a dry air supply line, the second inflow part is connected to the air outlet end of the air compressor via a branch line branching from the dry air supply line, and the second exhaust part is connected to an air inlet end of the air compressor via a circulation line. [9] The humidifying device for a fuel cell according to claim 7, wherein the fourth influencing part is formed by a communication hole connecting the main membrane module to the sub-membrane module. [10] Fuel cell system comprising: a stack formed from an electricity-generating assembly of fuel cell units; an air compressor for supplying air to a cathode of a fuel cell; a humidification device connected to the air compressor and performing membrane humidification of the exhaust gas discharged from the cathode and dry air supplied by the air compressor; and a hydrogen tank for supplying hydrogen to an anode of the fuel cell; wherein the humidification device includes a main membrane module including some bundles of first hollow fiber membranes arranged in the main membrane module, and a sub-membrane module connected to the main membrane module and some bundles of second hollow fiber membranes arranged in the sub-membrane module. [11] The fuel cell system according to claim 10, wherein humidification air discharged from the sub-membrane module is supplied into an air inlet end of the air compressor via a circulation line, and dry air compressed in the air compressor is cooled by the humidification air. [12] The fuel cell system according to claim 10, wherein the humidifying means supplies the dry air supplied from the air compressor to the main membrane module through an air supply line, supplies a part of the dry air to the sub-membrane module through a branch line branching from the dry air supply line, supplies the humidifying air discharged from the main membrane module to the cathode of the fuel cell through a humidifying air supply line, and supplies humidifying air discharged from the sub-membrane module to an air inlet end of the air compressor via a circulation line. [13] The fuel cell system according to claim 10, wherein the main membrane module and the sub-membrane module are integrally provided in a single casing, and are separated from each other by a partition wall in the casing. [14] The fuel cell system of claim 13, wherein the housing includes: a first inlet part which introduces the dry air supplied by the air compressor into the main membrane module, a second inlet part which introduces a part of the dry air supplied by the air compressor into the sub-membrane module, a third inlet part which introduces the exhaust gas emitted by the cathode of the fuel cell into the main membrane module, a fourth inflow part formed in the partition wall, connecting the main membrane module and the sub-membrane module, and introducing the exhaust gas into the sub-membrane module; a first exhaust part which discharges the humidification air which has been humidified in the main membrane module; a second exhaust part which discharges the humidification air which has been humidified in the sub-membrane module; a third exhaust part which discharges exhaust gas in which the moisture has been removed while the exhaust gas passes through the sub-membrane module from the main membrane module. [15] The fuel cell system according to claim 14, wherein the first inflow part is connected to an air outlet end of the air compressor via a dry air supply line, the second inflow part is connected to the air outlet end of the air compressor via a branch line branching from the dry air supply line, and the third inflow part is connected to the cathode of the fuel cell via an air outlet line, the first exhaust part is connected to the cathode of the fuel cell via a humidifying air supply line, and the second exhaust part is connected to an air inlet end of the air compressor via a circulation line. [16] A vehicle comprising the fuel cell system according to claim 10.

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