Fuel Cell Membrane Humidifier

Abstract

The present invention relates to a membrane humidifier for a fuel cell that not only prevents gas leakage due to repeated operation and shutdown of a fuel cell, but can also be manufactured with relatively low manufacturing costs and high productivity and suppresses vibrations that occur during operation. The membrane humidifier for a fuel cell includes a humidification module that humidifies air supplied from the outside to convert it into moisture in exhaust gas discharged from a fuel cell stack. The humidification module includes a mid-case that is open at both ends and has a step formed on its inner surface, at least one cartridge that is arranged within the mid-case and contains a plurality of hollow fiber membranes, a fixing layer on which the ends of the hollow fiber membranes are potted and supported by the inner wall of the mid-case, a bracket that is supported by the step of the mid-case and in contact with the fixing layer, and a packing member that has a groove into which the end of the mid-case is fitted and in contact with the bracket.

Description

[Technical field]

[0001] The present invention relates to a membrane humidifier for a fuel cell, and more specifically, to a membrane humidifier for a fuel cell that not only prevents gas leakage due to repeated operation and shutdown of the fuel cell, but also can be manufactured at relatively low manufacturing costs and with high productivity, and can suppress vibrations that occur during operation. [Background technology]

[0002] A fuel cell is a power generating battery that generates electricity by combining hydrogen and oxygen. Unlike general chemical batteries such as dry batteries and storage batteries, fuel cells can continuously generate electricity as long as hydrogen and oxygen are supplied, and have the advantages of no heat loss and being twice as efficient as an internal combustion engine. In addition, because the chemical energy produced by the combination of hydrogen and oxygen is directly converted into electrical energy, fuel cells emit less polluting substances. Therefore, fuel cells are not only environmentally friendly, but also have the advantage of reducing concerns about resource depletion due to increased energy consumption. Depending on the type of electrolyte used, such fuel cells can be broadly classified into polymer electrolyte membrane fuel cells (PEMFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), solid oxide fuel cells (SOFCs), alkaline fuel cells (AFCs), and the like. Although all of these fuel cells operate on the same fundamental principle, they differ in the type of fuel used, operating temperature, catalyst, electrolyte, etc. Among them, polymer electrolyte membrane fuel cells (PEMFCs) are known to be the most promising for use not only in small-scale stationary power generation equipment but also in transportation systems, as they operate at lower temperatures than other fuel cells, have high power density, and can be made compact. One of the most important factors in improving the performance of a polymer electrolyte fuel cell (PEMFC) is to maintain its function by supplying a certain amount of moisture to the polymer electrolyte membrane (PEM or proton exchange membrane) of the membrane electrode assembly (MEA). If the polymer electrolyte membrane dries out, the power generation efficiency drops sharply. There are three methods for humidifying a polymer electrolyte membrane: 1) a bubbler humidification method in which a pressure-resistant container is filled with water and the target gas is passed through a diffuser to supply moisture; 2) a direct injection method in which the amount of moisture required for the fuel cell reaction is calculated and moisture is supplied directly to the gas flow pipe via a solenoid valve; and 3) a humidification membrane method in which moisture is supplied to the gas flow bed using a polymer separation membrane.

[0003] Among these, the membrane humidification method, which utilizes a membrane that selectively allows only water vapor contained in exhaust gas to pass through and provides water vapor to air supplied to the polymer electrolyte membrane to humidify the polymer electrolyte membrane, is advantageous in that it allows the humidifier to be made lighter and smaller. The selectively permeable membrane used in the membrane humidification method is preferably a hollow fiber membrane, which has a large permeation area per unit volume when forming a module. That is, when manufacturing a humidifier using the hollow fiber membrane, it is possible to highly integrate hollow fiber membranes with a large contact surface area, and it has the advantages that the fuel cell can be sufficiently humidified even with a small capacity, low-cost materials can be used, and the moisture and heat contained in the off-gas discharged at high temperature from the fuel cell can be recovered and reused through the humidifier. As shown in FIG. 1, a conventional membrane humidification type humidifier 1000 includes a humidification module 1100 in which moisture exchange occurs between air supplied from the outside and exhaust gas discharged from a fuel cell stack (not shown), and caps 1200 respectively connected to both ends of the humidification module 1100. One of the caps 1200 transfers air supplied from the outside to the humidification module 1100, and the other transfers air humidified by the humidification module 1100 to the fuel cell stack. The humidification module 1100 includes a mid-case 1110 having an off-gas inlet 1110a and an off-gas outlet 1110b, and a number of hollow fiber membranes 1120 in the mid-case 1110. Both ends of the bundle of hollow fiber membranes 1120 are potted on a fixing layer 1130. The fixing layer 1130 is generally formed by curing a liquid polymer such as a liquid polyurethane resin through a casting method (e.g., dip casting or centrifugal casting).

[0004] Air supplied from the outside flows along the hollow of hollow fiber membrane 1120. Exhaust gas flowing into mid case 1110 through exhaust gas inlet 1110a comes into contact with the outer surface of hollow fiber membrane 1120 and is then discharged from mid case 1110 through exhaust gas outlet 1110b. When the exhaust gas comes into contact with the outer surface of hollow fiber membrane 1120, moisture contained in the exhaust gas permeates hollow fiber membrane 1120, thereby humidifying the air flowing along the hollow of hollow fiber membrane 1120. The internal space of the cap 1200 is fluidly connected only to the hollow of the hollow fiber membrane 1120, and must be completely isolated from the internal space of the mid case 1110. Otherwise, gas leakage due to pressure difference occurs, reducing the power generation efficiency of the fuel cell. 1, together with the fixing layer 1130, a resin layer 1140 between the fixing layer 1130 and the mid-case 1110 isolates the internal space of the cap 1200 from the internal space of the mid-case 1110. Similar to the fixing layer 1130, the resin layer 1140 is generally formed by curing a liquid polymer, such as a liquid polyurethane resin, via a casting method (dip casting or centrifugal casting). However, (i) as the fuel cell is repeatedly operated and stopped, the resin layer 1140 alternately expands and contracts, and the resin layer 1140 is likely to separate from the midcase 1110 due to the difference in thermal expansion coefficient between the midcase 1110 and the resin layer 1140, causing a gap between them, or (ii) as a result of vibration and / or impact, a gap is likely to occur between the resin layer 1140 and the midcase 1110. The gap between the resin layer 1140 and the midcase 1110 causes gas leakage, reducing the power generation efficiency of the fuel cell.

[0005] In order to prevent gas leakage due to gaps occurring between the resin layer 1140 and the midcase 1110, Korean Patent Registered No. 1697998 discloses a method of applying a sealant (liquid sealant) to the steps on the side of the resin layer 1140 and to the grooves formed by the inner surface of the midcase 1110, then fitting a packing member (solid-phase sealant) into the groove and hardening the sealant. However, such a method has problems of low productivity and high manufacturing costs in that (i) the sealant must be applied precisely to fit the groove, which makes it difficult to work with, (ii) it takes a fairly long time, more than 24 hours, to harden the sealant, and (iii) a separate space is required to store the humidification module 1100 until the sealant hardens. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a membrane humidifier for a fuel cell that can avoid problems caused by the limitations and shortcomings of the related art as described above, and that not only reliably prevents gas leakage due to repeated operation and shutdown of a fuel cell, but also can be manufactured at relatively low manufacturing costs and with high productivity, and can suppress vibrations that occur during operation. [Means for solving the problem]

[0007] The membrane humidifier for a fuel cell according to an embodiment of the present invention comprises: The humidification module includes a humidification module that humidifies air supplied from the outside into moisture contained in exhaust gas discharged from a fuel cell stack, and caps that are respectively coupled to both ends of the humidification module. The humidification module includes a midcase that is open at both ends and has a step formed on its inner circumferential surface, at least one cartridge that is disposed within the midcase and contains a plurality of hollow fiber membranes, a fixing layer on which the ends of the hollow fiber membranes are potted and supported by the inner wall of the midcase, a bracket that is supported by the step of the midcase and in contact with the fixing layer, and a packing member that has a groove into which the end of the midcase is fitted and in contact with the bracket. In the membrane humidifier for a fuel cell according to an embodiment of the present invention, the bracket and the packing member may each have a single closed curve shape corresponding to a cross-sectional shape of the midcase. In the membrane humidifier for a fuel cell according to an embodiment of the present invention, the bracket may have a higher hardness than the packing member. In the membrane humidifier for a fuel cell according to an embodiment of the present invention, the bracket may have a hardness of 60 to 100 Shore A, and the packing member may have a hardness of 40 to 50 Shore A. In the membrane humidifier of the fuel cell according to an embodiment of the present invention, the packing member includes soft rubber, and the bracket also includes metal, hard plastic or hard rubber. In the membrane humidifier of the fuel cell according to an embodiment of the present invention, the packing member includes silicone rubber or urethane rubber, and the bracket also includes polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC) or acrylic resin. In the membrane humidifier of the fuel cell according to the embodiment of the present invention, the packing member may also be in contact with the fixing layer.

[0008] In the membrane humidifier of the fuel cell according to an embodiment of the present invention, the fixing layer also includes a first fixing layer to which an end of the hollow fiber membrane is potted, and a second fixing layer surrounding the first fixing layer and contacting the bracket. In the membrane humidifier of the fuel cell according to the embodiment of the present invention, the first and second fixing layers may be made of the same material. In the membrane humidifier for a fuel cell according to an embodiment of the present invention, the first and second fixing layers both contain a polyurethane (PU) resin. In the membrane humidifier of the fuel cell according to an embodiment of the present invention, the humidification module further includes an inner case with both ends open within the mid case, and the hollow fiber membrane is also disposed within the inner case. In the membrane humidifier for a fuel cell according to an embodiment of the present invention, an end of the inner case may be potted to the first fixing layer. In the membrane humidifier of the fuel cell according to an embodiment of the present invention, a protrusion member may be formed on the inner wall of the packing member, which is fitted into the fixing layer and suppresses vibrations caused in the cartridge by air flowing inside the humidification module.

[0009] In addition, the membrane humidifier of the fuel cell according to the embodiment of the present invention comprises: The fuel cell stack includes a humidification module that humidifies air supplied from the outside to moisture contained in exhaust gas discharged from a fuel cell stack, and caps coupled to both ends of the humidification module, but the humidification module also includes a midcase with both ends open and a step formed on its inner circumferential surface, at least one cartridge arranged in the midcase and accommodating a plurality of hollow fiber membranes, a fixing layer to which the ends of the hollow fiber membranes are potted and supported by the inner wall of the midcase, a bracket supported by the step of the midcase and in contact with the fixing layer, and a packing member having a groove into which the end of the midcase is fitted and in contact with the bracket. The hollow fiber membranes include a first group of hollow fiber membranes and a second group of hollow fiber membranes. The humidification module further includes a first inner case in which the hollow fiber membranes of the first group are arranged, and a second inner case in which the hollow fiber membranes of the second group are arranged, and the fixing layer includes a first fixing layer in which ends of the hollow fiber membranes of the first group are potted, a second fixing layer in which ends of the hollow fiber membranes of the second group are potted, and a third fixing layer that surrounds the first fixing layer and the second fixing layer and contacts the bracket. In the membrane humidifier of the fuel cell according to an embodiment of the present invention, a protrusion member may be formed on the inner wall of the packing member, which is fitted into the fixing layer and suppresses vibrations caused in the cartridge by air flowing inside the humidification module. In the membrane humidifier for a fuel cell according to an embodiment of the present invention, an end of the first inner case may be potted to the first fixing layer, and an end of the second inner case may be potted to the second fixing layer. Effect of the Invention

[0010] According to the present invention, the sealant application process and sealant curing process required in the conventional technology are omitted, so that not only is workability improved, but the manufacturing time is shortened, and thus the productivity can be dramatically improved. In addition, since a separate space for storing the semi-finished product is not required for the sealant curing process, the production cost of the humidifier can be reduced. Also, not only can gas leakage caused by repeated operation and shutdown of the fuel cell be prevented, but the fuel cell can also be manufactured at relatively low manufacturing costs and with high productivity. In addition, a protrusion member is formed on the inner wall (or inner surface) of the packing member, which can suppress vibrations that occur during operation, can suppress the air inside the mid case from flowing to the cap, strengthens the sealing function, and can make it easier to select the position of the fixing layer when forming it. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an exploded perspective view illustrating a membrane humidifier for a fuel cell according to the prior art; [Diagram 2] 1 is a cross-sectional view illustrating a membrane humidifier of a fuel cell according to a first embodiment of the present invention; [Figure 3A] FIG. 1 is a perspective view of a bracket according to a first embodiment of the present invention. [Figure 3B] FIG. 3B is a cross-sectional view taken along line AA in FIG. 3A. [Figure 4A] FIG. 1 is a perspective view of a packing member according to a first embodiment of the present invention. [Figure 4B] FIG. 4B is a cross-sectional view taken along line AA in FIG. 4A. [Diagram 5] FIG. 4 is a cross-sectional view illustrating a membrane humidifier of a fuel cell according to a second embodiment of the present invention. [Figure 6A] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. [Figure 6B] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. [Figure 6C] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. [Figure 6D] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. [Figure 6E] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. [Figure 6F] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. [Figure 6G] 4A to 4C are cross-sectional views for explaining a method for manufacturing a membrane humidifier for a fuel cell according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention can be modified in various ways and can have various embodiments, but specific embodiments are illustrated and described in detail by detailed description. However, it should be understood that the present invention is not limited to the specific embodiments, but includes all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention. The terms used in the present invention are merely used to describe a particular embodiment and are not intended to limit the present invention. A singular expression includes a plural expression unless the context clearly dictates otherwise. In the present invention, the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and should be understood not to preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, a membrane humidifier for a fuel cell according to an embodiment of the present invention will be described with reference to the drawings. The cross-sectional views of Figures 2 and 5-6G are cross-sectional views of one end of the humidifier or blank, the other end having substantially the same (or symmetrical) cross-section. 2, the membrane humidifier 2000 of the fuel cell of the present invention includes a humidification module 2100 that humidifies air supplied from the outside with moisture in the exhaust gas discharged from the fuel cell stack. Both ends of the humidification module 2100 are fastened to caps 2200. One of the caps 2200 receives air from the outside through a port 2210 and transfers it to the humidification module 2100, and the other transfers the air humidified by the humidification module 2100 to the fuel cell stack through the port 2210. The cap 2200 may be made of hard plastic (e.g., polycarbonate, polyamide (PA), polyphthalamide (PPA), etc.) or metal, and may have a simple closed curve-shaped (e.g., circular or polygonal) traverse section. Here, it goes without saying that, depending on the design, one of the caps 2200 can supply exhaust gas to the humidification module 2100 and cause it to flow inside the hollow fiber membrane, and the other can discharge the exhaust gas after moisture exchange to the outside. In this case, external air can be introduced through one of the ports 2111 for exhaust gas inflow / outflow, which will be described later, and air humidified by the humidification module 2100 can be supplied to the fuel cell stack through the remaining one. The flow direction of the external air and the flow direction of the exhaust gas can be the same direction or opposite directions to each other. The humidification module 2100 according to one embodiment of the present invention is a device in which moisture exchange occurs between air supplied from the outside and exhaust gas supplied from a fuel cell stack, and includes a midcase 2110 with both ends open and having a step 2112 on its inner surface; a plurality of hollow fiber membranes 2121 inside the midcase 2110, a fixing layer 2122 to which the ends of the hollow fiber membranes 2121 are potted, a bracket 2130 supported by the steps 2112 of the midcase 2110 and in contact with the fixing layer 2122; and a packing member 2140 having a groove into which the end of the midcase 2110 is fitted and in contact with the bracket 2130, and a protrusion member 2150 protruding from the inner wall of the packing member 2140.

[0013] The midcase 2110 has a port 2111 (only one is shown in FIG. 2) for exhaust gas inflow / outflow. The midcase 2110 may be formed of a hard plastic (e.g., polycarbonate, polyamide (PA), polyphthalamide (PPA), etc.) or metal, and may have a cross-section in the form of a single closed curve (e.g., circular or polygonal). According to one embodiment of the present invention, the midcase 2110 may have a cross-section in the same form as the cap 2200. The hollow fiber membrane 2121 may contain polysulfone resin, polyethersulfone resin, sulfonated polysulfone resin, polyvinylidene fluoride (PVDF) resin, polyacrylonitrile (PAN) resin, polyimide resin, polyamideimide resin, polyesterimide resin, or a mixture of two or more of them. Air supplied from the outside through one cap 2200 is humidified as it flows along the hollow of the hollow fiber membrane 2121, and then transmitted to the fuel cell stack through another cap 2200. The exhaust gas flowing into mid case 2110 comes into contact with the outer surface of hollow fiber membrane 2121, and is then discharged from mid case 2110. When the exhaust gas comes into contact with the outer surface of hollow fiber membrane 2121, the moisture contained therein permeates hollow fiber membrane 2121, humidifying the air flowing along the hollow of hollow fiber membrane 2121. The fixing layer 2122 , which may be formed by a hard or soft polyurethane resin, must isolate the internal space of the cap 2200 from the internal space of the midcase 2110 so that the cap 2200 can only be in fluid communication with the hollow fiber membrane 2121 .

[0014] However, as described above, (i) as the fuel cell is repeatedly operated and stopped, the fixing layer 2122 alternately expands and contracts, and the fixing layer 2122 separates from the midcase 2110 due to the difference in thermal expansion coefficient between the midcase 2110 and the fixing layer 2122, creating a gap between them, and (ii) as a result of vibration and / or impact, a gap is likely to be created between the fixing layer 2122 and the midcase 2110. The gap between the fixing layer 2122 and the midcase 2110 causes gas leakage, reducing the power generation efficiency of the fuel cell. Gas leakage that may be caused by the occurrence of a gap between the fixed layer 2122 and the midcase 2110 includes (i) external leakage, in which exhaust gas in the internal space of the midcase 2110 passes sequentially through the gap between the fixed layer 2122 and the midcase 2110 and the gap between the cap 2200 and the midcase 2110, and escapes to the outside of the humidifier 2000, and (ii) internal leakage, in which exhaust gas in the internal space of the midcase 2110 passes sequentially through the gap between the fixed layer 2122 and the midcase 2110, and the gap between the fixed layer 2122 and the cap 2200, and enters the internal space of the cap 2200. In order to prevent gas leakage due to the occurrence of a gap between the fixed layer 2122 and the mid-case 2110 , the membrane humidifier 2000 of the fuel cell of the present invention further includes a bracket 2130 , a packing member 2140 and a protruding member 2150 . As shown in FIGS. 3A and 3B, the bracket 2130 supported by the step 2112 of the midcase 2110 may have a single closed curve shape corresponding to the cross-sectional shape of the midcase 2110. According to one embodiment of the present invention, the bracket 2130 has a higher hardness than the packing member 2140 and is strongly bonded to the fixing layer 2122 . For example, the packing member 2140 may have a relatively low hardness of 30 to 60 Shore A, more preferably 40 to 50 Shore A, so that it may be compressed by the pressure applied when the cap 2200 is fastened to the midcase 2110 via the bolt 2310 and nut 2320, and the bracket 2130 may have a hardness of 60 to 100 Shore A, more preferably 70 to 100 Shore A, which is higher than the hardness of the packing member 2140.

[0015] As shown in FIGS. 4A and 4B, the packing member 2140 having a groove G into which the end of the midcase 2110 is fitted may also have a single closed curve shape corresponding to the cross-sectional shape of the midcase 2110. According to one embodiment of the present invention, the packing member 2140 may include soft rubber (e.g., silicone rubber or urethane rubber), and the bracket 2130 may include metal, hard plastic (e.g., polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC) or acrylic resin), or hard rubber. When the cap 2200 is fastened to the mid case 2110 via the bolts 2310 and the nuts 2320, the portion of the packing member 2140 arranged between the cap 2200 and the mid case 2110 (particularly, the portion of the packing member 2140 corresponding to the groove into which the end of the mid case 2110 is pinched) is compressed by the pressure applied by the cap 2200 and the mid case 2110, thereby preventing gas migration (i.e., external leakage) through the interface between the packing member 2140 and the mid case 2110 and ensuring tight external sealing. In addition, since the bracket 2130 is not only supported by the step 2112 of the mid case 2110 but also has a relatively high hardness, when the cap 2200 is fastened to the mid case 2110 via the bolt 2310 and the nut 2320, the bracket 2130 can effectively apply pressure to the packing member 2140 together with the cap 2200 when the cap 2200 is fastened to the mid case 2110 via the bolt 2310 and the nut 2320. As a result, the portion of the packing member 2140 disposed between the cap 2200 and the bracket 2130 [i.e., located inside the mid case 2110] is sufficiently compressed, thereby preventing gas movement (i.e., internal leakage) through the interface between the packing member 2140 and the bracket 2130 and ensuring excellent internal sealing.

[0016] In addition, the bracket 2130 according to an embodiment of the present invention has excellent adhesive strength with the fixing layer 2122, thereby preventing gas movement (i.e., internal leakage) through the interface between the bracket 2130 and the fixing layer 2122 and providing stronger internal sealing. If necessary, the surface of the bracket 2130 may be treated with a primer to further improve the adhesive strength between the bracket 2130 and the fixing layer 2122 and maximize the internal sealing effect. The protruding member 2150 protrudes from the inner wall of the packing member 2140 toward the fixing layer 2122. The protruding member 2150 may be formed in an annular shape surrounding the inner wall of the packing member 2140. During manufacture, the protruding member 2150 may be fitted into the fixing layer 2122 by a pressure method. The protruding member 2150 may be fitted into the second fixing layer 2122-2. Here, it goes without saying that the protruding member 2150 may penetrate the second fixing layer 2122-2 and be fitted into the first fixing layer 2122-1. The protruding member 2150 compresses the fixing layer 2122 while being pressed into the fixing layer 2122, thereby preventing the air inside the mid case 2110 from migrating to the cap 2200 side, and enabling a tighter internal sealing. Furthermore, while being fitted into the fixing layer 2122 by a pressurized method, the protruding member 2150 compresses the fixing layer 2122, and can suppress vibrations generated in the cartridge 2120 by air flowing inside the humidification module 2100. That is, it is possible to suppress the cartridge 2120 from vibrating in the Z-axis direction due to the flow of dry air flowing in through the port 2210 of the cap (shown in the Z-axis direction in FIG. 2). Furthermore, since the protruding member 2150 protrudes from the inner wall of the mid case 2110 toward the fixing layer 2122, the position of the fixing layer can be easily selected when the fixing layer is formed during the manufacturing process. 2, the cap 2200 according to an embodiment of the present invention may have a cap protrusion 2220 at a position corresponding to the end of the mid-case 2110 that fits into the groove of the packing member 2140. The cap protrusion 2220, together with the end of the mid-case 2110, may more effectively compress the packing member 2140, thereby enabling a tighter external sealing. 2, the packing member 2140 according to an embodiment of the present invention may be in contact with the fixing layer 2122. The liquid resin (e.g., liquid polyurethane resin) used to form the fixing layer 2122 is cured while in contact with the packing member 2140, thereby improving the adhesive strength between the packing member 2140 and the fixing layer 2122 and enhancing the internal sealing.

[0017] According to one embodiment of the present invention, as shown in FIG. 2, the fixing layer 2122 also includes a first fixing layer 2122-1 to which the end of the hollow fiber membrane 2121 is potted, and a second fixing layer 2122-2 that surrounds the first fixing layer 2122-1 and contacts the bracket 2130. The first fixing layer 2122-1 and the second fixing layer 2122-2 can be formed by hardening a liquid resin such as liquid polyurethane resin through a dip casting method or a centrifugal casting method. The first fixing layer 2122-1 and the second fixing layer 2122-2 can be formed of different materials, but it is preferable that they are formed of the same material (e.g., polyurethane resin) in terms of adhesive strength therebetween. 2, the humidification module 2100 may further include an inner case 2123 with both ends open inside the mid case 2110. In this case, the hollow fiber membrane 2121 is disposed inside the inner case 2123. A first fixing layer 2122-1 to which the ends of the hollow fiber membrane 2121 are potted closes the open ends of the inner case 2123. According to one embodiment of the present invention, the inner case 2123 has a number of holes H at positions corresponding to the ports 2111 (only one is shown in FIG. 2) for exhaust gas inflow / outflow. Exhaust gas flowing into the mid case 2110 through the first port 2111 passes through the first hole H and then flows along the outer surface of the hollow fiber membrane 2121, losing moisture. Then, the exhaust gas passes through the second hole H on the opposite side, exits the inner case 2133, and is discharged from the mid case 2110 through the second port 2111. The hollow fiber membrane 2121 , the first fixing layer 2122 - 1 and the inner case 2123 constitute a hollow fiber membrane cartridge 2120 .

[0018] As shown in FIG. 2, an end of the inner case 2123 is potted to the first fixing layer 2122-1, so that the relative positions of the hollow fiber membrane 2121 and the inner case 2123 can be kept constant. In the following, with reference to FIG. 5, a membrane humidifier 2000 for a fuel cell according to a second embodiment of the present invention will be described. As shown in FIG. 5, the fuel cell membrane humidifier 2000 according to the second embodiment of the present invention is substantially identical to the first embodiment described above, except that it includes two hollow fiber membrane cartridges 2120a, 2120b. That is, according to the second embodiment of the present invention, the hollow fiber membranes include a first group of hollow fiber membranes 2121a and a second group of hollow fiber membranes 2121b, the humidification module 2100 includes a first inner case 2123a in which the hollow fiber membranes 2121a of the first group are arranged, and a second inner case 2123b in which the hollow fiber membranes 2121b of the second group are arranged, and the fixing layer 2122 includes a first fixing layer 2122-1a in which the ends of the hollow fiber membranes 2121a of the first group are potted, a second fixing layer 2122-1b in which the ends 2121b of the hollow fiber membranes of the second group are potted, and a third fixing layer 2122-2 that surrounds the first fixing layer 2122-1a and the second fixing layer 2122-1b and contacts the bracket 2130. The first group of hollow fiber membranes 2121a, the first fixing layer 2122-1a and the first inner case 2123a constitute a first hollow fiber membrane cartridge 2120a, and the second group of hollow fiber membranes 2121b, the second fixing layer 2122-1b and the second inner case 2123b constitute a second hollow fiber membrane cartridge 2120b. As shown in FIG. 5, the ends of the first inner case 2123a and the second inner case 2123b are potted into the first fixing layer 2122-1a and the second fixing layer 2122-1b, respectively, so that the relative positions of the first group of hollow fiber membranes 2121a and the first inner case 2123a, and the relative positions of the second group of hollow fiber membranes 2121b and the second inner case 2123b can each be maintained constant. To achieve a larger humidification capacity, the number of hollow fiber membranes 2121 must be increased. However, in the case of the first embodiment including only one hollow fiber membrane cartridge 2120, the more hollow fiber membranes 2121 there are, the more difficult it becomes for exhaust gas to be transmitted to the hollow fiber membrane 2121 located in the center.

[0019] In contrast, in the second embodiment of the present invention, since the two hollow fiber membrane cartridges 2120a, 2120b are arranged spaced apart from each other, even if the number of the entire hollow fiber membranes 2121a, 2121b is increased, the exhaust gas can be transmitted relatively uniformly to the entire hollow fiber membranes 2121a, 2121b. In other words, when the number of hollow fiber membranes is the same, the structure of the second embodiment including two hollow fiber membrane cartridges 2120a, 2120b is advantageous in terms of hollow fiber membrane utilization compared to the structure of the first embodiment including only one hollow fiber membrane cartridge 2120. The number of hollow fiber membrane cartridges to be installed in the mid case 2110 can be determined by taking into consideration the capacity of the fuel cell (or the required humidification capacity), the size of the humidifier, the weight of the humidifier, etc. Hereinafter, a method for manufacturing the membrane humidifier 2000 for a fuel cell according to an embodiment of the present invention will be described in more detail with reference to FIGS. 6A to 6G. First, as shown in FIG. 6A, a hollow fiber membrane cartridge 2120' is prepared in which the ends of a number of hollow fiber membranes 2121' are potted on a first fixing layer 2122-1'. The hollow fiber membrane cartridge 2120' may be manufactured by inserting at least a portion of each hollow fiber membrane 2121' into the inner case 2123, and then performing a dip casting process or a centrifugal casting process using a liquid resin such as liquid polyurethane resin. A first fixing layer 2122-1' in which the ends of the hollow fiber membranes 2121' are potted is formed through hardening of the liquid resin. When performing the dip casting process or the centrifugal casting process, the ends of the inner case 2123 are potted into the first fixing layer 2122-1' together with the ends of the hollow fiber membranes 2121'. The inner case 2123 may have a first group of holes H and a second group of holes H located on opposite sides to each other along its longitudinal direction. Next, as shown in FIG. 6B, a hollow fiber membrane cartridge 2120' is inserted into a mid case 2110 which has both open ends and a step 2112 formed on its inner circumferential surface.

[0020] According to an embodiment of the present invention, the mid case 2110 has an open end and a cross section in the form of a single closed curve. The mid case 2110 has a partition wall dividing its internal space into an exhaust gas inlet space and an exhaust gas outlet space located on opposite sides along the longitudinal direction, and the hollow fiber membrane cartridge 2120' can be fitted into holes formed in the partition wall and supported by the partition wall. At this time, the first group of holes H of the inner case 2123 is present in the exhaust gas inlet space, and the second group of holes H of the inner case 2123 is present in the exhaust gas outlet space. In this case, exhaust gas entering the exhaust gas inlet space flows into the inner case 2123 through the first group of holes H, flows toward the second group of holes H within the inner case 2123, moves to the exhaust gas exhaust space through the second group of holes H, and is then exhausted from the mid case 2110. 6C, the bracket 2130 is attached onto the step 2112 of the midcase 2110. As described above, the midcase 2110 has a cross-section in the form of a single closed curve, and the bracket 2130 may have a single closed curve shape corresponding to the cross-sectional shape of the midcase 2110. The bracket 2130 according to an embodiment of the present invention may be made of metal, hard plastic (e.g., polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC) or acrylic resin), or hard rubber. Optionally, the surface of the bracket 2130 may be treated with a primer before being mounted on the step 2112 of the mid case 2110. 6D, a packing member 2140 having a groove corresponding to the end of the mid case 2110 is mounted on the end of the mid case 2110 such that the end of the mid case 2110 is fitted into the groove and a part of the packing member 2140 contacts the bracket 2130. The packing member 2140 may also have a single closed curve shape corresponding to the cross-sectional shape of the mid case 2110. A protrusion member 2150 is formed on the inner surface of the packing member 2140.

[0021] Subsequently, as shown in FIG. 6E, a second fixing layer 2122-2' is formed to fill the gap between the mid case 2110, the bracket 2130, and the packing member 2140 and the end of the hollow fiber membrane cartridge 2120'. The second fixing layer 2122-2' may be manufactured by fastening a potting cap (not shown) to the mid case 2110, performing a dip casting process in which a liquid resin such as a liquid polyurethane resin is poured into the potting cap while the potting cap is positioned under the mid case 2110 and hardened, and then removing the potting cap. Alternatively, the second fixing layer 2122-2' may be formed through a centrifugal casting process. The first fixing layer 2122-1' and the second fixing layer 2122-2' can each be composed of a different liquid resin, but in terms of adhesive strength therebetween, it is desirable for them to be formed from the same substance (for example, liquid polyurethane resin). According to one embodiment of the present invention, the liquid resin (e.g., liquid polyurethane) used to form the second fixing layer 2122-2' is cured while in contact with the bracket 2130, the packing member 2140, and the protrusion member 2150, thereby improving the adhesion of the second fixing layer 2122-2' to them and strengthening the internal sealing. According to one embodiment of the present invention, since the bracket 2130 is formed of a material having excellent adhesive strength with the second fixing layer 2122-2', gas transfer (i.e., internal leakage) through the interface therebetween can be prevented and stronger internal sealing can be provided. Also, as described above, when the bracket 2130 surface-treated with a primer is used, the adhesive strength between the bracket 2130 and the second fixing layer 2122-2' is maximized, thereby providing better internal sealing. Next, the first fixing layer 2122-1', the second fixing layer 2122-2' and the hollow fiber membrane 2121' are simultaneously cut along the cutting line CL in Figure 6E to obtain a hollow fiber membrane 2121 with an open end potted on the first fixing layer 2122-1 surrounded by the second fixing layer 2122-2, as shown in Figure 6F. 6G, the cap 2200 is fastened to the mid-case 2110 such that the packing member 2140 is compressed by the cap 2200. As shown in FIG.

[0022] 6G, the cap 2200 according to an embodiment of the present invention may have a cap protrusion 2220 at a position corresponding to the end of the mid-case 2110 that fits into the groove of the packing member 2140. The cap protrusion 2220, together with the end of the mid-case 2110, may more effectively compress the packing member 2140, thereby enabling a tighter external sealing. Furthermore, according to an embodiment of the present invention, the bracket 2130 has a higher hardness than the packing member 2140, so that the packing member 2140 may be compressed when the cap 2200 is fastened to the mid-case 2110. That is, since the bracket 2130 is not only supported by the step 2112 of the mid case 2110, but also has a higher hardness (60 to 100 Shore A, more preferably 70 to 100 Shore A) than the hardness of the packing member 2140 (30 to 60 Shore A, more preferably 40 to 50 Shore A), when the cap 2200 is fastened to the mid case 2110 via the bolt 2310 and the nut 2320, the bracket 2130, together with the cap 2200, can effectively apply pressure to the packing member 2140. As a result, the portion of packing member 2140 disposed between cap 2200 and bracket 2130 [i.e., located inside mid-case 2110] is sufficiently compressed to prevent gas migration (i.e., internal leakage) through the interface between packing member 2140 and bracket 2130 and ensure excellent internal sealing.

[0023] According to the present invention described above, both external and internal leakage can be effectively prevented through mechanical assembly of the bracket 2130 and the packing member 2140 without the sealant application process and hardening process of the conventional technology. Therefore, according to the present invention, since the sealant application process and the sealant hardening process required in the conventional technology are omitted, not only the workability is improved, but also the manufacturing time is shortened, so that the productivity can be improved dramatically. In addition, since a separate space for storing the semi-finished product during the sealant hardening process is not required, the humidifier manufacturing cost can be reduced. In addition, since the protrusion member 2150 is formed on the inner wall of the packing member 2140, vibrations occurring during operation can be suppressed, the air inside the mid case can be suppressed from flowing to the cap, the sealing function can be strengthened, and the fixing layer position can be easily selected when the fixing layer is formed. Although one embodiment of the present invention has been described above, a person having ordinary knowledge in the art may modify and change the present invention in various ways by adding, changing, deleting or adding components within the scope of the concept of the present invention described in the claims, and these modifications and changes are also within the scope of the rights of the present invention.

Claims

1. a humidification module that humidifies air supplied from the outside to humidify the moisture contained in the exhaust gas discharged from the fuel cell stack; and a cap coupled to each end of the humidification module, The humidification module includes: A mid case having open ends and a step formed on an inner circumferential surface; At least one cartridge disposed in the midcase and housing a plurality of hollow fiber membranes; An anchoring layer to which the ends of the hollow fiber membranes are potted and supported by the inner wall of the midcase; A bracket supported by a step of the midcase and in contact with the fixing layer; a packing member having a groove into which an end of the mid case is fitted and contacting the bracket; a protrusion member is formed on an inner wall of the packing member, the protrusion member being fitted into the fixing layer and configured to suppress vibrations generated in the cartridge by air flowing inside the humidification module; Fuel cell membrane humidifier.

2. The bracket and the packing member are The fuel cell membrane humidifier of claim 1 , each having a single closed curve shape corresponding to a cross-sectional shape of the midcase.

3. The bracket is The membrane humidifier of the fuel cell according to claim 1 , having a higher hardness than the packing member.

4. 4. The membrane humidifier of claim 3, wherein the bracket has a hardness of 60 to 100 Shore A, and the packing member has a hardness of 40 to 50 Shore A.

5. The packing member includes a soft rubber, The fuel cell membrane humidifier of claim 1 , wherein the bracket comprises metal, hard plastic, or hard rubber.

6. The packing member includes silicone rubber or urethane rubber, 6. The fuel cell membrane humidifier of claim 5, wherein the bracket comprises polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC), or acrylic resin.

7. The packing member is The fuel cell membrane humidifier of claim 1 also in contact with said stationary layer.

8. The fixing layer is a first fixing layer in which the ends of the hollow fiber membranes are potted; 2. The fuel cell membrane humidifier of claim 1, further comprising: a second stationary layer surrounding said first stationary layer and in contact with said bracket.

9. 9. The membrane humidifier of claim 8, wherein the first and second immobilizing layers are made of the same material.

10. The membrane humidifier of claim 8 , wherein the first and second fixing layers both include polyurethane (PU) resin.

11. The humidification module further includes an inner case having both ends open and disposed within the mid case, The membrane humidifier for a fuel cell according to claim 8 , wherein the hollow fiber membrane is disposed within the inner case.

12. The membrane humidifier of claim 11 , wherein an end of the inner case is potted on the first fixing layer.

13. a humidification module that humidifies air supplied from the outside to humidify moisture contained in exhaust gas discharged from the fuel cell stack; and a cap coupled to each end of the humidification module, The humidification module includes: A mid case having open ends and a step formed on an inner circumferential surface; At least one cartridge disposed in the midcase and housing a plurality of hollow fiber membranes; An anchoring layer to which the ends of the hollow fiber membranes are potted and supported by the inner wall of the midcase; A bracket supported by a step of the midcase and in contact with the fixing layer; a packing member having a groove into which an end of the mid case is fitted and contacting the bracket; The hollow fiber membranes include a first group of hollow fiber membranes and a second group of hollow fiber membranes, The humidification module includes: a first inner case in which the first group of hollow fiber membranes is disposed; a second inner case in which the second group of hollow fiber membranes is disposed, The fixing layer is a first fixing layer in which the ends of the hollow fiber membranes of the first group are potted; a second fixing layer in which the ends of the hollow fiber membranes of the second group are potted; a third fixing layer surrounding the first fixing layer and the second fixing layer and in contact with the bracket; a protrusion member is formed on an inner wall of the packing member, the protrusion member being fitted into the fixing layer and configured to suppress vibrations generated in the cartridge by air flowing inside the humidification module; Fuel cell membrane humidifier.

14. An end of the first inner case is potted on the first fixing layer, The membrane humidifier of claim 13 , wherein an end of the second inner case is potted on the second fixing layer.

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