Membrane Humidifier for Fuel Cell

Abstract

A membrane humidifier for a fuel cell is disclosed that can be directly installed in a structure of a moving means such as a vehicle, ship, or aircraft, or in a generator system of a building without additional equipment, thereby improving the convenience of assembly, satisfying various mounting requirements of customers, and improving the convenience of manufacture. The disclosed membrane humidifier for a fuel cell includes a humidification module that performs moisture exchange between a first fluid and a second fluid, the humidification module including a midcase, a second fluid inlet for introducing the second fluid into the midcase, a second fluid outlet for discharging the second fluid to the outside, and at least one cartridge disposed in the midcase; caps formed on both ends of the humidification module; and a position-variable mount formed on the humidification module in a position-variable manner for mounting the humidification module to a target structure.

Description

Technical Field

[0001] The present invention relates to a membrane humidifier for a fuel cell. More specifically, it can be directly installed in a structure of a means of transportation such as a vehicle, ship, or aircraft, or a power generation system of a building without additional equipment, improving the assembly convenience, meeting various customer mounting requirements, and improving the manufacturing convenience. The present invention relates to a membrane humidifier for a fuel cell.

Background Art

[0002] A fuel cell is a power generation type battery that combines hydrogen and oxygen to produce electricity. Different from general chemical batteries such as dry batteries and storage batteries, as long as hydrogen and oxygen are supplied, it can continuously produce electricity, has no heat loss, and has the advantage of being about twice as efficient as an internal combustion engine. In addition, in order to directly convert chemical energy generated by the combination of hydrogen and oxygen into electrical energy, there is little emission of pollutants. Therefore, fuel cells have the advantages of being environmentally friendly and reducing the concern about resource depletion due to increased energy consumption. Such fuel cells can be roughly classified into polymer electrolyte membrane fuel cells (PEMFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), solid oxide fuel cells (SOFC), and alkaline fuel cells (AFC) according to the type of electrolyte used. Although each of these fuel cells operates on fundamentally the same principle, the types of fuel used, the operating temperature, the catalyst, the electrolyte, etc. are different from each other. Among them, the polymer electrolyte fuel cell (PEMFC) is known to be the most promising not only for small-scale stationary power generation equipment but also in transportation systems because it operates at a low temperature, has a high output density, and can be miniaturized compared to other fuel cells.

[0003] In improving the performance of the polymer electrolyte fuel cell (PEMFC), one of the most important factors is to maintain the function rate by supplying a certain amount or more of moisture to the polymer electrolyte membrane (PEM: polymer electrolyte membrane or proton exchange membrane) of the membrane-electrode assembly (MEA). This is because if the polymer electrolyte membrane dries out, the power generation efficiency drops sharply. As methods for humidifying the polymer electrolyte membrane, there are 1) the bubbler humidification method in which water is filled in a pressure-resistant container and then the target gas is passed through a diffuser to supply moisture, 2) the direct injection method in which the amount of supply moisture required for the fuel cell reaction is calculated and moisture is directly supplied to the gas flow pipe through a solenoid valve, and 3) the humidifying membrane method in which a polymer separation membrane is used to supply moisture to the gas flow layer. Among these, the membrane humidification method, which uses a membrane that selectively permeates only the water vapor contained in the exhaust gas and supplies the water vapor to the air supplied to the polymer electrolyte membrane to humidify the polymer electrolyte membrane, is advantageous in that the membrane humidifier can be reduced in weight and size. When forming a module, a selectively permeable membrane used for membrane humidification preferably uses a hollow fiber membrane with a large permeation area per unit volume. That is, when manufacturing a membrane humidifier using the hollow fiber membrane, high integration of the hollow fiber membrane with a large contact surface area is possible. Even with a small capacity, the fuel cell can be sufficiently humidified, low-cost materials can be used, and moisture and heat contained in the off-gas discharged from the fuel cell at a high temperature can be recovered and reused via the membrane humidifier.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a membrane humidifier for a fuel cell that can be directly installed in a structure of a moving means such as a vehicle, a ship, or an aircraft, or a generator system of a building without additional equipment, can improve the assembly convenience, can meet various customer mounting requirements, and can improve the manufacturing convenience.

Means for Solving the Problems

[0005] A membrane humidifier for a fuel cell according to an embodiment of the present invention includes a humidification module that exchanges moisture between a first fluid and a second fluid, a mid-case, a second fluid inlet for flowing the second fluid into the mid-case, a second fluid outlet for discharging the second fluid to the outside, and the at least one cartridge disposed in the mid-case; caps formed at both ends of the humidification module; and a position-variable mount formed to be position-variable with respect to the humidification module for mounting the humidification module to a structure to be mounted. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, the position-variable mount includes: a body portion formed with at least one or more second fastening ports fastened to a first fastening port formed on the surface of the mid-case by fastening means; a head portion formed by connecting with the body portion and formed with a third fastening port for being mounted on the structure to be mounted by fastening means; and a sliding portion formed on the lower surface of the body portion and slidably fitted into a rib formed on the surface of the mid-case. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, the fastening means is a bolt formed with a thread, and threads corresponding to the thread of the bolt can be formed in the first fastening port, the second fastening port, and the third fastening port. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, a guide groove can be formed at a position corresponding to the rib in the sliding portion. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, the mid-case also includes a partition wall partitioning the internal space of the mid-case into a first space and a second space, and a constant bypass hole passing through the partition wall and connecting the first space and the second space. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, the cartridge includes an inner case formed with a first mesh hole portion into which the second fluid flows, and a second mesh hole portion through which the second fluid flowing in through the first mesh hole portion is discharged to the outside after moisture exchange, and the first mesh hole portion and the second mesh hole portion can be formed in an asymmetric shape.

[0006] In the membrane humidifier of a fuel cell according to an embodiment of the present invention, it can be formed such that the total area of the mesh hole window on the first mesh hole portion side is larger than the total area of the mesh hole window on the second mesh hole portion side. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, when the sizes of the mesh hole windows of the first mesh hole portion and the second mesh hole portion are the same, the number of mesh holes forming the first mesh hole portion can be formed to be larger than the number of mesh holes forming the second mesh hole portion. In the membrane humidifier of a fuel cell according to an embodiment of the present invention, when the number of mesh hole windows of the first mesh hole portion and the second mesh hole portion are the same, the area of each individual mesh hole forming the first mesh hole portion can be formed to be larger than the area of each individual mesh hole forming the second mesh hole portion. In addition, specific matters of embodiments according to various aspects of the present invention are included in the following detailed description.

Effects of the Invention

[0007] According to an embodiment of the present invention, without additional equipment, it can be directly provided in structures of moving means such as vehicles, ships, and aircraft, or in a power generation system of a building, improving the assembly convenience, meeting various customer mounting requirements, and improving the manufacturing convenience.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0009] The present invention can be subjected to various transformations and can have various embodiments. Specific embodiments are illustrated and described in detail by way of detailed description. However, they are not intended to limit the present invention to the specific embodiments, and it must be understood that they include all transformations, equivalents, or alternatives included in the spirit and technical scope of the present invention. The terms used in the present invention are merely used for the description of specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, terms such as "including" or "having" are used to specify the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it must be understood that they do not preclude the possibility of the existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, with reference to the drawings, a membrane humidifier of a fuel cell according to an embodiment of the present invention will be described. FIG. 1 is a front view showing a membrane humidifier of a fuel cell according to an embodiment of the present invention, FIG. 2 is a plan view showing a membrane humidifier of a fuel cell according to an embodiment of the present invention, FIG. 3 is a drawing showing a position-variable mount, FIGS. 4 and 5 are plan views showing an exemplary form in which the position-variable mount varies its position on the humidification module, FIG. 6 is a side view of a humidification module with the cap of the membrane humidifier of the fuel cell removed according to an embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line A-A' of FIG. 2. As shown in FIGS. 1 to 7, a membrane humidifier of a fuel cell according to an embodiment of the present invention includes a humidification module 110, a cap 120, and a position-variable mount 200. The humidification module 110 performs moisture exchange between a first fluid supplied from the outside and a second fluid discharged from a fuel cell stack (not shown). The cap 120 is fastened to both ends of the humidification module 110. A first fluid inlet 121 for supplying the first fluid supplied from the outside to the humidification module 110 is formed in one of the caps 120, and a first fluid outlet 122 for supplying the first fluid humidified by the humidification module 110 to the fuel cell stack is formed in the other one.

[0010] The humidification module 110 includes a mid-case 111 having a second fluid inlet 112 and a second fluid outlet 113, and at least one cartridge 20 disposed in the mid-case 111. The second fluid discharged from the fuel cell stack (not shown) flows into the second fluid inlet 112, is subjected to moisture exchange in the humidification module 110, and then is discharged from the second fluid outlet 113. A first fastening port H1 is formed on the surface of the mid-case 111. The first fastening port H1 can be fastened to a second fastening port H2, which will be described later, by a fastening means. In this specification, the fluid flowing into / discharged from the second fluid inlet 112 or the second fluid outlet 113 is not limited to the second fluid. Also, the fluid flowing into / discharged from the first fluid inlet 121 or the first fluid outlet 122 is not limited to the first fluid. By design, one of the caps 120 supplies the second fluid to the humidification module 110 so that it flows inside the hollow fiber membrane, and the other can discharge the second fluid after moisture exchange to the outside. Also, in that case, the first fluid flows in through either one of the second fluid inlet 112 or the second fluid outlet 113, and the first fluid humidified by the humidification module 110 is supplied to the fuel cell stack through the other one. The flow direction of the first fluid and the flow direction of the second fluid are either in the same direction or in opposite directions to each other. The mid-case 111 and the cap 120 can each be independently formed of a rigid plastic or metal and can have a circular or polygonal cross-section in the width direction. The circular shape includes an elliptical shape, and the polygonal shape includes a polygon with rounded corners. For example, the rigid plastic can also be polycarbonate, polyamide (PA), polyphthalamide (PPA), polypropylene (PP), etc. The internal space of the mid-case 111 can be partitioned into a first space S1 and a second space S2 by a partition wall 114. The partition wall 114 can be provided with an insertion port H into which at least one or more cartridges 20 can be inserted. A gasket 116 can be provided between the mid-case 111 and the cartridge 20. The gasket 116 attaches the cartridge 20 to the humidification module 110 through mechanical assembly. Therefore, when an abnormality occurs in a specific part of the humidification module 110 (for example, the cartridge 20), after mechanically and easily separating the mid-case 111 and the gasket 116 from the humidification module 110, it is possible to repair or replace only that part.

[0011] In an embodiment of the present invention, a position-variable mount 200 for mounting a membrane humidifier of a fuel cell including a humidification module 110 to a structure to be mounted is included. The structure to be mounted may mean a fuel cell stack, a part of a moving means such as a vehicle, a ship, or an aircraft to which a fuel cell system including a membrane humidifier of a fuel cell is mounted, or a part of a power generation system of a building. Hereinafter, an example in which the membrane humidifier of the fuel cell of the present invention is mounted to a vehicle structure will be described. Referring to FIGS. 1 and 2, the position-variable mount 200 is also mounted on the upper surface of the humidification module 110. Here, without being limited thereto, it goes without saying that the position-variable mount 200 may be mounted on the side surface or the lower surface of the humidification module 110, or may be mounted on the surface of the cap 120 according to the design. The position-variable mount 200 can be fixed to the humidification module 110 via fastening means after being arranged at a desired position on the surface of the humidification module 110 by an operator according to the structure shape of the vehicle to which it is to be attached. Such a position-variable mount 200 will be described with reference to FIG. 3. FIG. 3(a) is a front view of the position-variable mount 200, FIG. 3(b) is a plan view, FIG. 3(c) is a bottom view, and FIGS. 3(d) and 3(e) are left and right side views. Referring to FIG. 3, the position-variable mount 200 includes a body portion 210, a head portion 220, and a sliding portion 230.

[0012] The body portion 210 is also formed in a predetermined shape, for example, a rectangular shape, and at least one or more second fastening holes H2 are formed. By the fastening means, while the second fastening hole H2 is fastened to the first fastening hole H1, the position-variable mount 200 can be fixed to the surface of the humidification module 110. For example, the fastening means may also be a bolt with a thread formed thereon, and threads corresponding to the thread of the bolt may be formed on the inner surfaces of the first fastening hole H1 and the second fastening hole H2. The head portion 220 is formed by being connected to the body portion 210. For example, as shown in FIG. 3, the head portion 220 may be formed by extending from one end of the upper surface of the body portion 210. At least one or more third fastening holes H3 are formed in the head portion 220. The third fastening holes H3 enable the position-variable mount 200 to be attached to the structure of the vehicle by fastening means. The sliding portion 230 is formed on the lower surface of the body portion 210. The sliding portion 230 is slidably fitted into a rib 111a protruding from the surface of the mid-case 111. A guide groove 231 may be formed at a position corresponding to the rib 111a in the sliding portion 230. Due to the guide groove 231, the sliding portion 230 cannot be detached from the rib 111a but can be moved in the direction of the rib 111a. In one embodiment of the present invention, since the position-variable mount 200 can be integrally formed with the membrane humidifier of the fuel cell, the need for separate additional equipment (separate mounts and brackets therefor) can be reduced. Also, as shown in FIGS. 4 and 5, the position-variable mount 200 can be moved while sliding along ribs formed on the surface of the humidification module 110 or, by design, on the surface of the cap 120, reducing the design of a new humidification module to reflect customer mounting requirements (mounting position, assembly structure, etc.). Therefore, various customer mounting requirements can be satisfied, and manufacturing convenience can be improved.

[0013] Referring to FIGS. 6 and 7, the membrane humidifier of the fuel cell according to the embodiment of the present invention also includes a constant bypass hole 115 formed in the partition wall 114. The constant bypass hole 115 is formed to penetrate the partition wall 114 with a predetermined shape. The constant bypass hole 115 connects the first space S1 and the second space S2 partitioned by the partition wall 114. Part of the second fluid flowing into the second fluid inlet 112 always flows from the first space S1 to the second space S2 through the bypass hole 115 and is discharged from the second fluid outlet 113. Since the second fluid flowing through the bypass hole 115 at all times does not come into contact with the first fluid, no moisture exchange occurs. If the volume of the membrane humidifier of the fuel cell is reduced, the differential pressure inside the membrane humidifier of the fuel cell will increase due to the second fluid flowing in from the fuel cell stack. Since such an increased differential pressure has an adverse effect on the efficiency of the membrane humidifier of the fuel cell, it is necessary to eliminate the differential pressure. Since the bypass hole 115 at all times bypasses a part of the incoming second fluid around the hollow fiber membrane and discharges it to the outside, the increase in differential pressure can be eliminated. Therefore, the bypass hole 115 at all times is advantageous for reducing the size of the membrane humidifier of the fuel cell. Next, referring to FIGS. 8 to 10, a cartridge attached to a membrane humidifier of a fuel cell according to an embodiment of the present invention will be described. FIG. 8 is a perspective view showing a cartridge attached to a membrane humidifier of a fuel cell according to an embodiment of the present invention, FIG. 9 is a cross-sectional view showing a cartridge attached to a membrane humidifier of a fuel cell according to an embodiment of the present invention, and FIG. 10 is a drawing for comparing the flow distance of the second fluid between a conventional cartridge (upper drawing) and a cartridge according to an embodiment of the present invention (lower drawing). In an embodiment of the present invention, the cartridge 20 can also improve the humidification efficiency by adjusting the number and area of the mesh hole windows W forming the mesh hole part. Referring to FIG. 9, the cartridge 20 includes a large number of hollow fiber membranes 21, a potting part 22, and an inner case 23.

[0014] The hollow fiber membrane 21 also includes a polymer membrane formed of a polysulfone resin, a polyethersulfone resin, a sulfonated polysulfone resin, a polyvinylidene fluoride (PVDF) resin, a polyacrylonitrile (PAN) resin, a polyimide resin, a polyamideimide resin, a polyesterimide resin, or a mixture of at least two of them. The potting portion 22 fixes the ends of the hollow fiber membrane 21. The potting portion 22 is also formed by curing a liquid resin such as a liquid polyurethane resin through a casting method such as dip potting or centrifugal potting. The inner case 23 has openings at each end and houses a large number of hollow fiber membranes 21 inside. The potting portion 22 where the ends of the hollow fiber membrane 21 are potted closes the openings of the inner case 23. The inner case 23 includes a first mesh hole portion MH1 arranged in a mesh form for fluid communication with the first space S1 and a second mesh hole portion MH2 arranged in a mesh form for fluid communication with the second space S2. The second fluid that flows into the first space S1 of the mid-case 111 through the second fluid inlet 112 flows into the inner case 23 through the first mesh hole portion MH1 and contacts the outer surface of the hollow fiber membrane 21. Subsequently, the second fluid that has exchanged moisture with the first fluid exits the second space S2 through the second mesh hole portion MH2 and is then discharged from the mid-case 111 through the second fluid outlet 113. The cartridge 20 can be formed such that the total area of the mesh hole window W on the side of the first mesh hole portion MH1 is larger than the total area of the mesh hole window W on the side of the second mesh hole portion MH2. The mesh hole window W is an opening through which the second fluid flows in and is discharged. By increasing the total area of the mesh hole window W on the side of the first mesh hole portion MH1 formed on the side of the second fluid inlet 112, the inflow of the second fluid into the inner case 23 can be smoothed, and by reducing the total area of the mesh hole window W on the side of the second mesh hole portion MH2 formed on the side of the second fluid outlet 113, the flow of the second fluid in the inner case 23 can be promoted.

[0015] Also, by forming the first mesh hole portion MH1 and the second mesh hole portion MH2 asymmetrically, the distance between the first mesh hole portion MH1 and the second mesh hole portion MH2 becomes larger than in the case of a symmetric shape, thereby increasing the flow distance of the second fluid in the inner case 23 (see reference signs L1 and L2 in FIG. 10). By increasing the flow distance of the second fluid, the time during which the second fluid is in contact with the surface of the hollow fiber membrane 220 can be extended, and the humidification efficiency can be improved as a whole. When the sizes of the mesh hole windows W of the both-side mesh hole portions are the same, the number of mesh holes forming the first mesh hole portion MH1 is made larger than the number of mesh holes forming the second mesh hole portion MH2. Also, when the number of the mesh hole windows W of the both-side mesh hole portions is the same, the area of each mesh hole forming the first mesh hole portion MH1 is made larger than the area of each mesh hole forming the second mesh hole portion MH2. In this way, in the embodiment of the present invention, the shapes of the first mesh hole portion MH1 and the second mesh hole portion MH2 are formed into an asymmetric shape, and it is possible to promote the flow of the second fluid in the inner case 23 and improve the humidification efficiency by increasing the flow distance of the second fluid.

[0016] As described above, the embodiments of the present invention have been described. However, those having ordinary knowledge in the art can variously modify and change the present invention by adding, changing, deleting, or adding components within the scope not departing from the idea of the present invention described in the claims, and that is also included within the scope of the rights of the present invention.

Claims

1. A humidification module that performs moisture exchange between a first fluid and a second fluid, includes a mid-case, a second fluid inlet for allowing the second fluid to flow into the mid-case, a second fluid outlet for discharging the second fluid to the outside, and at least one cartridge disposed within the mid-case. Caps formed at both ends of the humidification module. A position-variable mount that is formed to be position-variable with respect to the humidification module and is for mounting the humidification module to a structure to be mounted. The position-variable mount includes: A body portion formed with at least one or more second fastening openings that are fastened to a first fastening opening formed on the surface of the mid-case by fastening means. A head portion that is connected and formed with the body portion and is formed with a third fastening opening for being mounted to the structure to be mounted by fastening means. A sliding portion formed on the lower surface of the body portion and slidably fitted into a rib formed on the surface of the mid-case. The sliding portion has a guide groove formed at a position corresponding to the rib. A membrane humidifier for a fuel cell.

2. The fastening means is a bolt formed with a thread, and the first fastening opening, the second fastening opening, and the third fastening opening are formed with threads corresponding to the thread of the bolt. The membrane humidifier for a fuel cell according to Claim 1.

3. The mid-case includes: A partition wall that divides the internal space of the mid-case into a first space and a second space, and a constant bypass hole that penetrates the partition wall and connects the first space and the second space. The membrane humidifier for a fuel cell according to Claim 1.

4. The cartridge includes: An inner case formed with a first mesh hole portion into which the second fluid flows, and a second mesh hole portion through which the second fluid that has flowed in through the first mesh hole portion is discharged to the outside after moisture exchange. The first mesh hole portion and the second mesh hole portion are formed in an asymmetric shape. The membrane humidifier for a fuel cell according to Claim 1.

5. The membrane humidifier for a fuel cell according to Claim 4, wherein the total area of the mesh hole windows on the first mesh hole portion side is formed to be larger than the total area of the mesh hole windows on the second mesh hole portion side.

6. When the sizes of the mesh hole windows of the first mesh hole portion and the second mesh hole portion are the same, the number of mesh holes forming the first mesh hole portion is formed to be larger than the number of mesh holes forming the second mesh hole portion. The membrane humidifier for a fuel cell according to claim 5.

7. When the number of mesh hole windows of the first mesh hole portion and the second mesh hole portion are the same, the area of each mesh hole forming the first mesh hole portion is formed to be larger than the area of each mesh hole forming the second mesh hole portion. The membrane humidifier for a fuel cell according to claim 5.

8. The structure to be mounted is a structure of a moving means or a generator system of a building. The membrane humidifier for a fuel cell according to claim 1.

Images