Humidifier cartridge for fuel cell and humidifier for fuel cell

Abstract

The present invention relates to a humidifier cartridge for a fuel cell and a humidifier for a fuel cell, which includes an inner case open at both ends, a hollow fiber membrane bundle housed in the inner case, an inner inlet and an inner outlet formed in the inner case spaced apart in a first axial direction, a first pot layer fixing one end of the hollow fiber membrane bundle at one end of the inner case, and a second pot layer fixing the other end of the hollow fiber membrane bundle at the other end of the inner case, and which has a packing density of 0.405 or more and 0.625 or less based on the pot cross-sectional area inside one end of the inner case where the first pot layer is potted and the membrane cross-sectional area of ​​the hollow fiber membrane bundle, based on a second axial direction perpendicular to the first axial direction.

Description

[Technical Field]

[0001] The present invention relates to a humidifier for a fuel cell for supplying humidified gas to a fuel cell. [Background technology]

[0002] Unlike ordinary chemical batteries such as dry cells and storage batteries, fuel cells can continue to produce electricity as long as hydrogen and oxygen are supplied, and because there is no heat loss, they have the advantage of being about twice as efficient as internal combustion engines.

[0003] In addition, because the chemical energy generated by the combination of hydrogen and oxygen is directly converted into electrical energy, fuel cells emit fewer pollutants, making them environmentally friendly and reducing concerns about resource depletion due to increased energy consumption.

[0004] Depending on the type of electrolyte used, such fuel cells can be broadly 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).

[0005] 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. In particular, polymer electrolyte membrane fuel cells (PEMFCs) are known to be the most promising fuel cell for small-scale stationary power generation equipment as well as transportation systems, as they operate at lower temperatures than other fuel cells and can be made smaller due to their high power density.

[0006] One of the most important factors in improving the performance of polymer electrolyte membrane fuel cells (PEMFCs) is to maintain a certain moisture content in the polymer electrolyte membrane (Polymer Electrolyte Membrane or Proton Exchange Membrane: PEM) of the membrane electrode assembly (MEA). If the PEM dries out, the power generation efficiency drops sharply.

[0007] 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 through a solenoid valve; and 3) a humidification membrane method in which moisture is supplied to the gas flow bed using a polymer separation membrane.

[0008] Among these, the membrane humidification method, which uses a membrane that selectively allows only water vapor contained in exhaust gas to pass through and humidifies the polymer electrolyte membrane by providing water vapor to the air supplied to the polymer electrolyte membrane, is advantageous in that it allows the humidifier to be made lighter and smaller.

[0009] The selectively permeable membrane used in membrane humidification is preferably a hollow fiber membrane, which has a large permeation area per unit volume when forming a module. In other words, when a humidifier is manufactured using hollow fiber membranes, hollow fiber membranes with a large contact surface area can be highly integrated, which has the advantages of sufficient humidification of a fuel cell even with a small capacity, the use of inexpensive materials, and the recovery of moisture and heat from the high-temperature off-gas emitted from the fuel cell for reuse in the humidifier.

[0010] FIG. 1 is a schematic exploded perspective view of a typical fuel cell humidifier.

[0011] As illustrated in FIG. 1, a typical membrane humidification type humidifier 100 includes a humidification module 110 in which moisture exchange occurs between air supplied from the outside and exhaust gas discharged from a fuel cell stack (not shown), and gaps 120 connected to both ends of the humidification module 110.

[0012] One of the gaps 120 transfers externally supplied air to the humidifying module 110, and the other transfers air humidified by the humidifying module 110 to the fuel cell stack.

[0013] The humidification module 110 includes a mid-case 111 having an off-gas inlet 111a and an off-gas outlet 111b, and a plurality of hollow fiber membranes 112 within the mid-case 111. Both ends of the bundle of hollow fiber membranes 112 are potted in a fixing layer 113. The fixing layer 113 is generally formed by hardening a liquid polymer such as a liquid polyurethane resin using a casting method. The fixing layer 113 to which the ends of the hollow fiber membranes 112 are potted and a resin layer 114 between the fixing layer 113 and the mid-case 111 isolate the interior space of the cap 120 from the interior space of the mid-case 111. Like the fixing layer 113, the resin layer 114 is generally formed by hardening a liquid polymer such as a liquid polyurethane resin using a casting method.

[0014] Air supplied from the outside flows along the hollow of the hollow fiber membrane 112. The exhaust gas that flows into the midcase 111 from the wet exhaust gas inlet 111a comes into contact with the outer surface of the hollow fiber membrane 112 and then flows out of the midcase 111 through the wet exhaust gas outlet 111b. When the exhaust gas comes into contact with the outer surface of the hollow fiber membrane 112, moisture contained in the exhaust gas permeates the hollow fiber membrane 112, thereby humidifying the air flowing along the hollow of the hollow fiber membrane 112.

[0015] Recently, fuel cells have been used in various applications, such as hydrogen-powered vehicles, and in order to improve the performance of fuel cells, humidifiers for fuel cells are required to have high humidifying efficiency. Therefore, there is an urgent need to develop technology that can improve the humidifying efficiency of humidifiers for fuel cells. Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention has been devised to solve the above-mentioned needs, and aims to provide a fuel cell humidifier cartridge and a fuel cell humidifier that can have the humidification efficiency required by fuel cells. [Means for solving the problem]

[0017] In order to solve the above problems, the present invention may include the following configurations.

[0018] A humidifier for a fuel cell according to the present invention may include a humidification module for humidifying externally supplied dry gas using wet gas discharged from a fuel cell stack, a first cap coupled to one end of the humidification module, and a second cap coupled to the other end of the humidification module. The humidification module may include a mid-case having both open ends and at least one cartridge disposed within the mid-case. The cartridge may include an inner case having both open ends, a hollow fiber membrane bundle housed in the inner case, an inner inlet and an inner outlet spaced apart in a first axial direction in the inner case, a first pot layer for fixing one end of the hollow fiber membrane bundle to one end of the inner case, and a second pot layer for fixing the other end of the hollow fiber membrane bundle to the other end of the inner case. The packing density based on the pot cross-sectional area inside one end of the inner case where the first pot layer is potted and the membrane cross-sectional area of ​​the hollow fiber membrane bundle may be 0.405 or more and 0.625 or less, based on a second axis direction perpendicular to the first axis direction.

[0019] The humidifier cartridge for a fuel cell according to the present invention is a cartridge for a fuel cell humidifier for humidifying dry gas supplied from an external source using wet gas discharged from a fuel cell stack, and may include an inner case open at both ends, a hollow fiber membrane bundle housed in the inner case, an inner inlet and an inner outlet spaced apart in a first axial direction in the inner case, a first potting layer that secures one end of the hollow fiber membrane bundle at one end of the inner case, and a second potting layer that secures the other end of the hollow fiber membrane bundle at the other end of the inner case. A packing density based on a pot cross-sectional area within one end of the inner case where the first potting layer is potted and a membrane cross-sectional area of ​​the hollow fiber membrane bundle may be 0.405 or more and 0.625 or less, based on a second axial direction perpendicular to the first axial direction. [Effects of the Invention]

[0020] The present invention can contribute to improving fuel cell performance by being embodied in a way that allows a fuel cell to have the required humidification efficiency using a packing density related to the proportion of hollow fiber membrane bundles. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic exploded perspective view of a typical fuel cell humidifier.

[0022] [Figure 2] 1 is a schematic exploded perspective view of a humidifier for a fuel cell according to the present invention;

[0023] [Figure 3] 3 is a schematic exploded cross-sectional view showing the fuel cell humidifier according to the present invention, taken along line II in FIG. 2. FIG.

[0024] [Figure 4] 3 is a schematic cross-sectional view of the humidifier for a fuel cell according to the present invention, taken along line II in FIG. 2. FIG.

[0025] [Figure 5] 1 is a schematic plan view of a cartridge of a fuel cell humidifier according to the present invention.

[0026] [Figure 6] FIG. 6 is a schematic cross-sectional side view showing the cartridge of the fuel cell humidifier according to the present invention taken along line II-II in FIG. 5.

[0027] [Figure 7] FIG. 7 is a schematic side cross-sectional view showing an enlarged view of part A in FIG. 6.

[0028] [Figure 8] 1 is a graph showing the change in transmembrane pressure, case pressure, and total pressure due to packing density.

[0029] [Figure 9] 1 is a graph showing the change in humidification efficiency depending on packing density.

[0030] [Figure 10] 1 is a table showing the humidification efficiency, transmembrane pressure difference, case pressure difference, and total pressure difference of Comparative Examples and Examples according to packing density.

[0031] [Figure 11] FIG. 6 is a conceptual cross-sectional side view showing a hollow fiber membrane bundle taken along line II-II in FIG. 5. [Figure 12] FIG. 6 is a conceptual cross-sectional side view showing a hollow fiber membrane bundle taken along line II-II in FIG. 5.

[0032] [Figure 13] 1 is a schematic exploded perspective view of an embodiment of a humidifier for a fuel cell according to the present invention, in which two cartridges are coupled to a mid-case;

[0033] [Figure 14] 1 is a schematic exploded perspective view of an embodiment of a humidifier for a fuel cell according to the present invention, in which three cartridges are coupled to a mid-case. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, embodiments of a humidifier for a fuel cell according to the present invention will be described in detail with reference to the accompanying drawings. Since the cartridge of the humidifier for a fuel cell according to the present invention can be included in the humidifier for a fuel cell according to the present invention, the cartridge will be described together with the embodiment of the humidifier for a fuel cell according to the present invention.

[0035] 2 to 4, 10 and 11, a humidifier 1 for a fuel cell according to the present invention is for humidifying dry gas supplied from the outside using wet gas discharged from a fuel cell stack (not shown). The dry gas may be fuel gas or air. The dry gas may be humidified by the wet gas and then supplied to the fuel cell stack. The humidifier 1 for a fuel cell according to the present invention includes a humidification module 2 for humidifying the dry gas, a first cap 3 coupled to one end of the humidification module 2, and a second cap 4 coupled to the other end of the humidification module 2.

[0036] 2 to 5, the humidification module 2 humidifies gas supplied from the outside. The first cap 3 may be coupled to one end of the humidification module 2. The second cap 4 may be coupled to the other end of the humidification module 2. The first cap 3 may deliver dry gas to the humidification module 2. In this case, the second cap 4 may deliver the dry gas humidified by wet gas in the humidification module 2 to the fuel cell stack. The first cap 3 may deliver wet gas to the humidification module 2. In this case, the second cap 4 may discharge the wet gas after humidifying the dry gas in the humidification module 2 to the outside.

[0037] The humidification module 2 includes a mid-case 21 and at least one cartridge 22 .

[0038] The mid-case 21 is coupled with the cartridge 22. The cartridge 22 can be disposed inside the mid-case 21. The mid-case 21 is open at both ends. In this case, a receiving hole 211 can be formed in the mid-case 21. The receiving hole 211 can be formed to penetrate the mid-case 21 in a first axis direction (X-axis direction).

[0039] The mid case 21 may be formed with a mid inlet 212 and a mid outlet 213. The mid inlet 212 may allow wet gas or dry gas to flow into the mid case 21. The mid outlet 213 may allow wet gas or dry gas to flow out from the mid case 21. The mid inlet 212 and the mid outlet 213 may be disposed at positions spaced apart from each other in the first axis direction (X-axis direction).

[0040] When wet gas flows through the mid inlet 212 and the mid outlet 213, the wet gas passes through the mid case 21 and enters the cartridge 22 through the mid inlet 212, and then comes into contact with the outer surface of the hollow fiber membrane bundle 221. During this process, moisture contained in the wet gas permeates the hollow fiber membrane bundle 221, humidifying the dry gas flowing through the hollow fiber membrane bundle 221. The humidified dry gas flows out of the hollow fiber membrane bundle 221 and can be supplied to the fuel cell stack through the second cap 4. After humidifying the dry gas, the wet gas flows out of the cartridge 22, passes through the mid case 21, and then exits the mid case 21 through the mid outlet 213. The mid inlet 212 is connected to the fuel cell stack to receive wet gas. In this case, the wet gas may be off-gas discharged from the fuel cell stack.

[0041] When dry gas flows through the mid inlet 212 and the mid outlet 213, the dry gas passes through the mid case 21 and enters the cartridge 22 through the mid inlet 212, and then contacts the outer surface of the hollow fiber membrane bundle 221 of the cartridge 22. During this process, moisture from the wet gas flowing along the hollow of the hollow fiber membrane bundle 221 permeates the hollow fiber membrane bundle 221, humidifying the dry gas flowing into the cartridge 22. The humidified dry gas flows out of the cartridge 22, passes through the mid case 21, and exits the mid case 21 through the mid outlet 213 before being supplied to the fuel cell stack. The wet gas obtained by humidifying the dry gas flows out of the hollow fiber membrane bundle 221 and can be discharged to the outside through the second cap 4. The first cap 3 is connected to the fuel cell stack to receive the wet gas. In this case, the wet gas may be off-gas discharged from the fuel cell stack.

[0042] The mid inlet 212 and the mid outlet 213 may protrude from the mid case 21. The mid inlet 212 and the mid outlet 213 may protrude in the same direction from the mid case 21. The mid inlet 212 and the mid outlet 213 may protrude in different directions from the mid case 21. The mid inlet 212, the mid outlet 213, and the mid case 21 may be integrally formed.

[0043] The cartridge 22 is disposed within the midcase 21. The cartridge 22 can include a hollow fiber membrane bundle 221. The hollow fiber membrane bundle 221 can include a plurality of hollow fiber membranes 221a. The hollow fiber membrane bundle 221 can be modularized by being coupled to the cartridge 22. Thus, by coupling the cartridge 22 to the midcase 21, the hollow fiber membrane bundle 221 can be installed inside the midcase 21. Therefore, the humidifier 1 for a fuel cell according to the present invention can improve the ease of installation, separation, and replacement of the hollow fiber membrane bundle 221.

[0044] The cartridge 22 may include an inner case 222 .

[0045] The inner case 222 is open at both ends. In this case, openings may be formed at both ends of the inner case 222. The hollow fiber membrane bundle 221 is accommodated inside the inner case 222. The hollow fiber membrane bundle 221 may be modularized by being disposed inside the inner case 222. The hollow fiber membrane bundle 221 may include a polymer membrane formed of 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 these.

[0046] The cartridge 22 may include a first potting layer 223. The first potting layer 223 fixes one end of the hollow fiber membrane bundle 221 to one end of the inner case 222. In this case, the first potting layer 223 may be formed so as not to block the hollow of the hollow fiber membrane bundle 221. The first potting layer 223 may be formed by hardening a liquid resin, such as a liquid polyurethane resin, through a casting process. The first potting layer 223 may fix one end of the hollow fiber membrane bundle 221 to the inner case 222. A portion of the first potting layer 223 may be located inside the inner case 222, and the remaining portion may be located outside the inner case 222.

[0047] The cartridge 22 may include a second potting layer 224. The second potting layer 224 secures the other end of the hollow fiber membrane bundle 221 at the other end of the inner case 222. In this case, the second potting layer 224 may be formed so as not to block the hollow of the hollow fiber membrane bundle 221. Therefore, dry gas or wet gas can be supplied to the hollow of the hollow fiber membrane bundle 221 without interfering with the second potting layer 224 and the first potting layer 223, and can flow out of the hollow fiber membrane bundle 221 without interfering with the second potting layer 224 and the first potting layer 223. The second potting layer 224 may be formed by hardening a liquid resin, such as a liquid polyurethane resin, through a casting process. The second potting layer 224 may secure the other end of the inner case 210 and the hollow fiber membrane bundle 221. A portion of the second pot layer 224 may be located inside the inner case 222, and the remaining portion may be located outside the inner case 222. The second pot layer 224 and the first pot layer 223 may be spaced apart from each other in the first axis direction (X-axis direction).

[0048] The cartridge 22 may include an inner inlet 225 and an inner outlet 226 .

[0049] The inner inlet 225 is formed in the inner case 222. The inner inlet 225 may be formed on one side of the inner case 222. For example, one side of the inner case 222 may correspond to the top surface. The inner inlet 225 may allow wet gas or dry gas to flow into the inner case 222. The inner inlet 225 may be formed through the inner case 222. The inner inlet 225 may be embodied as a single through-hole through the inner case 222. As shown in FIG. 5, the inner inlet 225 may also be embodied as a plurality of through-holes through the inner case 222. In this case, the inner inlet 225 may include a plurality of inlet windows 225a formed through different portions of the inner case 222. The inlet windows 225a may be arranged in a matrix, spaced apart from each other along the first axis (X-axis) and the second axis (Y-axis) directions. The second axis direction (Y axis direction) is perpendicular to the first axis direction (X axis direction).

[0050] The inner outlet 226 is formed in the inner case 222. The inner outlet 226 may be formed on one side of the inner case 222. The inner outlet 226 may allow wet gas or dry gas to flow out from the inside of the inner case 222. The inner outlet 226 may be formed through the inner case 222. The inner outlet 226 may be implemented as a single through-hole through the inner case 222. As shown in FIG. 5, the inner outlet 226 may also be implemented as a plurality of through-holes through the inner case 222. In this case, the inner outlet 226 may include a plurality of outlet windows 226a formed through different portions of the inner case 222. The outlet windows 226a may be arranged in a matrix, spaced apart from each other along the first axis (X-axis) and the second axis (Y-axis). The inner outlet 226 and the inner inlet 225 may be arranged at positions spaced apart from each other along the first axis (X-axis).

[0051] When wet gas flows through the inner outlet 226 and the inner inlet 225, the wet gas is supplied between the inner surface of the midcase 21 and the outer surface of the inner case 222 through the mid inlet 212, and then supplied into the inner case 222 through the inner inlet 225, where it can come into contact with the outer surface of the hollow fiber membrane bundle 221. During this process, moisture contained in the wet gas permeates the hollow fiber membrane bundle 221, thereby humidifying the dry gas flowing along the hollow of the hollow fiber membrane bundle 221. The humidified dry gas then flows out of the hollow fiber membrane bundle 221 and can be supplied to the fuel cell stack through the second cap 4. The wet gas obtained by humidifying the dry gas flows between the outer surface of the inner case 222 and the inner surface of the midcase 21 through the inner outlet 226, and then flows out of the midcase 21 through the mid outlet 213.

[0052] When dry gas flows through the inner outlet 226 and the inner inlet 225, the dry gas is supplied between the inner surface of the mid case 21 and the outer surface of the inner case 222 through the mid inlet 212, and then supplied into the inner case 222 through the mid inlet 212 to come into contact with the outer surface of the hollow fiber membrane bundle 221. During this process, moisture from the wet gas flowing along the hollow of the hollow fiber membrane bundle 221 permeates the hollow fiber membrane bundle 221, thereby humidifying the dry gas that has flowed into the inner case 222. The humidified dry gas flows between the outer surface of the inner case 222 and the inner surface of the mid case 21 through the inner outlet 226, and then flows out of the mid case 21 through the mid outlet 213, where it can be supplied to the fuel cell stack. The wet gas obtained by humidifying the dry gas flows out of the hollow fiber membrane bundle 221 and can be discharged to the outside through the second cap 4.

[0053] 2 to 4, the humidifying module 2 may be implemented to seal the space between the mid-case 21 and the cartridge 22 by mechanical assembly without a casting process. In this case, the humidifying module 2 may include a first packing member 23.

[0054] The first packing member 23 can be coupled to one end of the humidification module 2. Therefore, the first packing member 23 allows the first cap 3 to be in fluid communication only with the hollow fiber membrane bundle 221. In this case, the first packing member 23 can prevent direct mixing of dry gas and wet gas. The first packing member 23 can be airtightly coupled to one end of the humidification module 2 through mechanical assembly. Therefore, the humidifier 1 for a fuel cell according to the present invention can omit a casting process, which requires a relatively long process time, thereby shortening the manufacturing process time and improving productivity. The first packing member 23 can be made of a material that can be elastically deformed. For example, the first packing member 23 can be made of rubber. The first packing member 23 can be formed in a ring shape to seal the gap between the cartridge 22 and the midcase 21.

[0055] The humidification module 2 may include a second packing member 24 .

[0056] The second packing member 24 can be coupled to the other end of the humidification module 2. Therefore, the second packing member 24 allows the second cap 4 to be in fluid communication only with the hollow fiber membrane bundle 221. In this case, the second packing member 24 can prevent direct mixing of dry gas and wet gas. The second packing member 24 can be airtightly coupled to the other end of the humidification module 2 through mechanical assembly. Therefore, the humidifier 1 for a fuel cell according to the present invention can omit a casting process, which requires a relatively long process time, thereby shortening the manufacturing process time and improving productivity. The second packing member 24 can be formed of an elastically deformable material. For example, the second packing member 24 can be formed of rubber. The second packing member 24 can be formed in a ring shape to seal the gap between the cartridge 22 and the midcase 21.

[0057] 2 to 4, the first cap 3 is coupled to one end of the humidifying module 2. The first cap 3 can transfer dry gas or wet gas supplied from the outside to the humidifying module 2.

[0058] 2 to 4, the second cap 4 is coupled to the other end of the humidification module 2. The second cap 4 can discharge dry gas or wet gas transferred from the humidification module 2 to the outside. When humidified dry gas is transferred from the humidification module 2, the second cap 4 can transfer the humidified dry gas to the fuel cell stack.

[0059] The humidifier 1 for a fuel cell according to the present invention can be embodied to improve humidification efficiency depending on the packing density, which will be explained in detail below with reference to Figures 2 to 10. In Figure 10, the comparative examples and examples are arranged from top to bottom in order of packing density, from smallest to largest.

[0060] The packing density relates to the ratio between the internal volume of the inner case 222 and the hollow fiber membrane bundle 221. As the packing density increases, the volume occupied by the hollow fiber membrane bundle 221 relative to the internal volume of the inner case 222 increases, and as the packing density decreases, the volume occupied by the hollow fiber membrane bundle 221 relative to the internal volume of the inner case 222 decreases. The increase in packing density can be achieved by at least one of an increase in the volume occupied by the hollow fiber membrane bundle 221 and a decrease in the internal volume of the inner case 222. The decrease in packing density can be achieved by at least one of a decrease in the volume occupied by the hollow fiber membrane bundle 221 and an increase in the internal volume of the inner case 222. The increase or decrease in the volume occupied by the hollow fiber membrane bundle 221 can be achieved by an increase or decrease in the number of hollow fiber membranes 221a included in the hollow fiber membrane bundle 221.

[0061] In the fuel cell humidifier 1 according to the present invention, the packing density can be calculated based on the membrane cross-sectional area and the pot cross-sectional area.

[0062] The membrane cross-sectional area may correspond to the cross-sectional area of ​​the hollow fiber membrane bundle 221 based on the second axis direction (Y-axis direction). The cross-sectional area of ​​the hollow fiber membrane bundle 221 may be a value obtained by adding up the unit cross-sectional areas of the hollow fiber membranes 221a of the hollow fiber membrane bundle 221 based on the second axis direction (Y-axis direction). The unit cross-sectional area may be calculated based on the external diameter 221D of the hollow fiber membrane 221a (see FIG. 7). In this case, the unit cross-sectional area is a value including the cross-sectional area of ​​the hollow 221b (see FIG. 7) of the hollow fiber membrane 221a.

[0063] The pot cross-sectional area may correspond to the cross-sectional area of ​​the interior of one end of the inner case 222 where the first pot layer 223 is potted, based on the second axis direction (Y-axis direction). In this case, the packing density can be calculated by regarding the cross-sectional area of ​​the interior of one end of the inner case 222 as a value equivalent to the internal volume of the inner case 222. The pot cross-sectional area may correspond to the combined value of the cross-sectional area of ​​the first pot layer 223 and the cross-sectional area of ​​the membrane, based on the second axis direction (Y-axis direction). In this case, the pot cross-sectional area may be a value obtained by multiplying the width 222H (see FIG. 6) of the inner case 222 by the thickness 222T (see FIG. 6) of the inner case 222. The width 222H of the inner case 222 and the thickness 222T of the inner case 222 are based on the inner surface of the inner case 222. The thickness 222T of the inner case 222 is based on a third axis direction (Z-axis direction) perpendicular to both the first axis direction (X-axis direction) and the second axis direction (Y-axis direction). Meanwhile, the cross-sectional area of ​​the pot may be the same as the cross-sectional area of ​​the other end of the inner case 222 where the second pot layer 224 is potted, based on the second axis direction (Y axis direction).

[0064] The packing density can be calculated based on the cross-sectional area of ​​the pot and the cross-sectional area of ​​the membrane as described above. The packing density can be a value obtained by dividing the cross-sectional area of ​​the membrane by the cross-sectional area of ​​the pot. In this case, the packing density can be defined as the ratio of the cross-sectional area of ​​the membrane to the cross-sectional area of ​​the pot. The humidification efficiency of the fuel cell humidifier 1 according to the present invention can be changed depending on the packing density. This will be explained in detail as follows.

[0065] First, as the packing density increases, the membrane cross-sectional area increases. As the membrane cross-sectional area increases, the combined cross-sectional area of ​​the hollows 221b of the hollow fiber membrane bundle 221 increases, increasing the area through which dry or wet gas can pass through the hollow fiber membrane bundle 221. Therefore, the differential pressure (hereinafter referred to as "transmembrane pressure") acting when dry or wet gas passes through the hollow fiber membrane bundle 221 decreases. This can be confirmed by the fact that the transmembrane pressure decreases as the packing density increases in the graph shown in FIG. 8.

[0066] Next, as the packing density increases, the transmembrane differential pressure decreases, and therefore humidification efficiency should continue to increase. However, as shown in FIG. 9, it can be seen that humidification efficiency does not continue to increase as the packing density increases. This is because as the cross-sectional area of ​​the membrane increases, the passage area through which wet or dry gas can pass within the inner case 222 relatively decreases, resulting in an increase in the differential pressure (hereinafter referred to as the "case differential pressure") acting when the wet or dry gas passes through the inner case 222, which affects humidification efficiency. This can be confirmed by the fact that the case differential pressure increases as the packing density increases in the graph shown in FIG. 8. As the packing density changes, the case differential pressure changes more than the transmembrane differential pressure. As a result, as the packing density changes, the change in the overall differential pressure (hereinafter referred to as the "total differential pressure") acting on the cartridge 22 is more significantly affected by the change in the case differential pressure. This can be confirmed by the similarity between the total differential pressure and the case differential pressure in the graph shown in FIG. 8.

[0067] As described above, when the number of hollow fiber membranes 221a in the hollow fiber membrane bundle 221 is increased, the passage area through which dry gas or wet gas can pass through the hollow fiber membrane bundle 221 increases, so it can be expected that the humidification efficiency will continue to improve as the packing density increases. However, in reality, as the packing density increases, the passage area through which wet gas or dry gas can pass inside the inner case 222 decreases, causing the case differential pressure to increase, and it can be seen that the humidification efficiency does not continue to improve.

[0068] Based on this, the packing density of the humidifier 1 for fuel cells according to the present invention can be embodied as 0.405 or more and 0.625 or less. As shown in Figures 8 and 9, when expressed as a percentage, the packing density of the humidifier 1 for fuel cells according to the present invention can be embodied as 40.5% or more and 62.5% or less. Therefore, the humidifier 1 for fuel cells according to the present invention is embodied to have a packing density that can increase humidification efficiency, thereby contributing to improving the performance of the fuel cell. This will be explained in detail with reference to Figures 8 to 10 as follows.

[0069] First, when the packing density is less than 0.405 (percentage: less than 40.5%), the case differential pressure is low due to an increase in the passage area through which wet or dry gas can pass inside the inner case 222, but the membrane differential pressure is significantly high due to a decrease in the passage area through the hollow fiber membrane bundle 221 through which dry or wet gas can pass, resulting in a high total differential pressure. Therefore, when the packing density is less than 0.405, a low humidification efficiency of less than 27% is observed. For example, in Comparative Example 1, where the packing density is 0.38 (percentage: 38%), the case differential pressure is low at 4.3 kPa, but the membrane differential pressure is significantly high at 14.1 kPa, resulting in a high total differential pressure of 18.4 kPa. Therefore, Comparative Example 1 exhibits a low humidification efficiency of 23.5%.

[0070] In contrast, when the packing density is 0.405 or more (percentage: 40.5% or more), the case differential pressure is slightly higher than when the packing density is less than 0.405 (percentage: less than 40.5%), but the transmembrane differential pressure is significantly lower, resulting in a significantly lower total differential pressure. Therefore, when the packing density is 0.405 or more, a high humidification efficiency of 27% or more is exhibited. For example, in Example 1, where the packing density is 0.405 (percentage: 40.5%), the case differential pressure is slightly higher at 5.1 kPa than in Comparative Example 1, but the transmembrane differential pressure is significantly lower at 9.7 kPa, resulting in a lower total differential pressure of 14.8 kPa. Therefore, Example 1 exhibits a humidification efficiency of 27.1%, higher than Comparative Example 1.

[0071] Next, when the packing density exceeds 0.625 (percentage: exceeding 62.5%), the transmembrane pressure difference is low due to an increase in the passage area through which dry or wet gas can pass through the hollow fiber membrane bundle 221, but the case pressure difference is significantly high due to a decrease in the passage area through which wet or dry gas can pass inside the inner case 222, resulting in a high total pressure difference. Therefore, when the packing density exceeds 0.625, a low humidification efficiency of less than 27% is observed. For example, in Comparative Example 2, where the packing density is 0.65 (percentage: 65%), the transmembrane pressure difference is low at 4.1 kPa, but the case pressure difference is significantly high at 13.8 kPa, resulting in a high total pressure difference of 17.9 kPa. Therefore, Comparative Example 2 exhibits a low humidification efficiency of 23.1%.

[0072] In contrast, when the packing density is 0.625 or less (percentage: 62.5% or less), the transmembrane pressure difference is slightly higher than when the packing density exceeds 0.625 (percentage: above 62.5%), but the case pressure difference is significantly lower, resulting in a significantly lower total pressure difference. Therefore, when the packing density is 0.625 or less, a high humidification efficiency of 27% or more is exhibited. For example, in Example 2, where the packing density is 0.625 (percentage: 62.5%), the transmembrane pressure difference is slightly higher at 5.3 kPa than in Comparative Example 2, but the case pressure difference is significantly lower at 9.9 kPa, resulting in a lower total pressure difference of 15.2 kPa. Therefore, Example 2 exhibits a humidification efficiency of 27%, higher than Comparative Example 2.

[0073] As described above, the humidifier 1 for a fuel cell according to the present invention is embodied with a packing density of 0.405 or more and 0.625 or less, and therefore has a high humidifying efficiency by significantly reducing the total differential pressure compared to comparative examples in which the packing density is embodied as 0.405 or less or more than 0.625. Therefore, the humidifier 1 for a fuel cell according to the present invention can increase the humidification rate of the gas supplied to the fuel cell stack, thereby contributing to improving the performance of the fuel cell.

[0074] 2 to 10, the humidifier 1 for a fuel cell according to the present invention may be embodied with a packing density of 0.51 or more (percentage: 51% or more). Therefore, the humidifier 1 for a fuel cell according to the present invention can have higher humidification efficiency. This will be explained in detail as follows.

[0075] In Example 3, where the packing density is 0.51 (percentage: 51%), the transmembrane pressure difference is 6.5 kPa, the case pressure difference is 6.4 kPa, and the difference between the transmembrane pressure and the case pressure difference is very small, resulting in a low total pressure difference of 12.9 kPa. Therefore, Example 3 exhibits a high humidification efficiency of 29.9%, which is very close to 30%. This humidification efficiency of Example 3 is improved compared to the humidification efficiency of 27.1% of Example 1, where the packing density is 0.405 (percentage: 40.5%).

[0076] On the other hand, in Example 4, where the packing density is 0.435 (percentage: 43.5%), the transmembrane pressure difference is 7.9 kPa and the case pressure difference is 6 kPa, and the difference between the transmembrane pressure difference and the case pressure difference is larger than in Example 3, so that Example 4 shows a total pressure difference of 13.9 kPa, which is larger than Example 3. Therefore, Example 4 shows a humidification efficiency of 29%, which is lower than Example 3. However, Example 4 also shows a humidification efficiency that is significantly higher than Comparative Example 1, and also a humidification efficiency that is higher than Example 1.

[0077] 2 to 10, the humidifier 1 for a fuel cell according to the present invention may be embodied with a packing density of 0.53 or less (percentage: 53% or less). Therefore, the humidifier 1 for a fuel cell according to the present invention can have higher humidification efficiency. This will be explained in detail as follows.

[0078] In Example 5, where the packing density is 0.53 (percentage: 53%), the transmembrane pressure difference is 6.3 kPa, the case pressure difference is 6.6 kPa, and the difference between the transmembrane pressure and the case pressure difference is very small, resulting in a low total pressure difference of 12.9 kPa. Therefore, Example 5 exhibits a high humidification efficiency of 30.1%, exceeding 30%. This humidification efficiency of Example 5 is improved compared to the humidification efficiency of 27% of Example 2, where the packing density is 0.625 (percentage: 62.5%).

[0079] On the other hand, in Example 6, where the packing density is 0.595 (percentage: 59.5%), the transmembrane pressure difference is 6.5 kPa and the case pressure difference is 8.1 kPa, and since the difference between the transmembrane pressure difference and the case pressure difference is larger than in Example 5, it shows a total pressure difference of 14.3 kPa, which is higher than in Example 5. Therefore, Example 6 shows a humidification efficiency of 28.9%, which is lower than in Example 5. However, Example 6 also shows a humidification efficiency that is significantly higher than Comparative Example 2, and also higher than Example 2.

[0080] 2 to 10, the humidifier 1 for a fuel cell according to the present invention may be embodied with a packing density of 0.51 to 0.53 (percentage: 51% to 53%). Therefore, the humidifier 1 for a fuel cell according to the present invention not only has high humidification efficiency, but also has safety in terms of the total differential pressure and humidification efficiency. This can be confirmed by the fact that in Example 3, where the packing density is 0.51 (percentage: 51%), and Example 5, where the packing density is 0.53 (percentage: 53%), the transmembrane pressure is the same at 12.9 kPa, the humidification efficiency is approximately the same at about 30%, and the difference between the transmembrane pressure and the case differential pressure is approximately the same at 0.3 kPa or less, resulting in the dry gas and the wet gas having approximately the same fluidity. Therefore, the humidifier 1 for fuel cells according to the present invention is realized with a packing density of 0.51 to 0.53 (percentage: 51% to 53%), thereby guaranteeing a certain level of quality to users and improving product reliability.

[0081] 2 to 12, in the humidifier 1 for a fuel cell according to the present invention, when the width 221H of the hollow fiber membrane bundle 221 is 1, the thickness 221T of the hollow fiber membrane bundle 221 can be embodied as 0.1 or more and 0.8 or less. Therefore, the humidifier 1 for a fuel cell according to the present invention is embodied to have various humidification efficiencies, thereby improving versatility by being applicable to fuel cells used in various applications. This will be explained in detail as follows. Hereinafter, the ratio of the thickness 221T to the hollow fiber membrane bundle 221 is based on the assumption that the width 221H of the hollow fiber membrane bundle 221 is 1.

[0082] First, the thickness 221T of the hollow fiber membrane bundle 221 is based on the third axis direction (Z-axis direction). The thickness 222T of the hollow fiber membrane bundle 221 may be the same as the thickness 222T of the inner surface of the inner case 222 or may be smaller than the thickness 222T of the inner surface of the inner case 222. The width 221H of the hollow fiber membrane bundle 221 is based on the second axis direction (Y-axis direction). The width 221H of the hollow fiber membrane bundle 221 may be the same as the width 222H of the inner surface of the inner case 222 or may be smaller than the width 222H of the inner surface of the inner case 222.

[0083] Next, if the thickness 221T of the hollow fiber membrane bundle 221 is less than 0.1, the thickness 221T of the hollow fiber membrane bundle 221 is too thin, making it difficult to provide a sufficient number of hollow fiber membranes 221a. If the thickness 221T of the hollow fiber membrane bundle 221 is more than 0.8, the thickness 221T of the hollow fiber membrane bundle 221 is too thick, which may result in a low utilization efficiency of the hollow fiber membranes 221a disposed relatively closer to the inside.

[0084] In contrast, in the humidifier 1 for a fuel cell according to the present invention, the thickness 221T of the hollow fiber membrane bundle 221 is embodied as 0.1 to 0.8, so that not only can a sufficient number of hollow fiber membranes 221a be provided, but also the utilization efficiency of the hollow fiber membranes 221a arranged relatively inward can be increased.

[0085] Meanwhile, in the humidifier 1 for a fuel cell according to the present invention, when the thickness 222T of the hollow fiber membrane bundle 221 is more than 0.6 and not more than 0.8, the usage efficiency of the hollow fiber membranes 221a disposed relatively inner in the hollow fiber membrane bundle 221 may be somewhat reduced, but instead the usage life of the hollow fiber membrane bundle 221 can be further extended. In this case, the humidifier 1 for a fuel cell according to the present invention can be suitably applied to applications where the usage life is more important than the humidification efficiency.

[0086] Furthermore, in the humidifier 1 for a fuel cell according to the present invention, when the thickness 222T of the hollow fiber membrane bundle 221 is equal to or greater than 0.1 and less than 0.2, the service life of the hollow fiber membrane bundle 221 may be shortened to some extent, but instead the service efficiency of the hollow fiber membranes 221a disposed relatively inner in the hollow fiber membrane bundle 221 can be improved. In this case, the humidifier 1 for a fuel cell according to the present invention can be suitably applied to applications where humidifying efficiency is more important than service life.

[0087] Furthermore, in the humidifier 1 for a fuel cell according to the present invention, when the thickness 222T of the hollow fiber membrane bundle 221 is between 0.2 and 0.6, a good balance can be achieved between the service life of the hollow fiber membrane bundle 221 and the service efficiency of the hollow fiber membranes 221a disposed relatively inner in the hollow fiber membrane bundle 221. In this case, the humidifier 1 for a fuel cell according to the present invention can be suitably applied to applications where a balance between humidification efficiency and service life is important.

[0088] As described above, the humidifier 1 for a fuel cell according to the present invention is embodied such that the thickness 221T of the hollow fiber membrane bundle 221 is 0.1 or more and 0.8 or less, and therefore can be embodied to have various humidification efficiencies and service lives, thereby improving versatility and allowing it to be applied to fuel cells used in various applications.

[0089] 13 and 14, in the humidifier 1 for a fuel cell according to the present invention, two or more cartridges 22 may be disposed within the mid-case 21. As shown in FIG. 13, two cartridges 22, 22' may be disposed within the mid-case 21. As shown in FIG. 14, three cartridges 22, 22', 22" may be disposed within the mid-case 21. Although not shown, four or more cartridges 22 may be disposed within the mid-case 21.

[0090] The present invention described above is not limited to the above-described embodiments and accompanying drawings, and it will be apparent to those skilled in the art to which the present invention pertains that various substitutions, modifications and alterations are possible within the scope of the technical idea of ​​the present invention.

Claims

1. a humidification module for humidifying externally supplied dry gas using wet gas discharged from the fuel cell stack; a first cap coupled to one end of the humidification module; a second cap coupled to the other end of the humidification module; The humidification module comprises: A mid-case with open ends and At least one cartridge disposed within the mid-case; The cartridge comprises: An inner case with both ends open, a hollow fiber membrane bundle housed in the inner case; an inner inlet and an inner outlet formed in the inner case and spaced apart from each other in a first axial direction; a first pot layer that fixes one end of the hollow fiber membrane bundle at one end of the inner case; a second pot layer that fixes the other end of the hollow fiber membrane bundle at the other end of the inner case, a packing density based on a pot cross-sectional area inside one end of the inner case where the first pot layer is potted and a membrane cross-sectional area of ​​the hollow fiber membrane bundle, in a second axis direction perpendicular to the first axis direction, of 0.405 to 0.625; A humidifier for a fuel cell, wherein when the width of the hollow fiber membrane bundle is 1, the thickness of the hollow fiber membrane bundle is more than 0.2 and not more than 0.

6.

2. The membrane cross-sectional area is a value obtained by adding up the unit cross-sectional areas based on the external diameters of the hollow fiber membranes in the hollow fiber membrane bundle, the pot cross-sectional area is a sum of the cross-sectional area of ​​the first pot layer and the cross-sectional area of ​​the membrane based on the second axial direction, 2. The humidifier for a fuel cell according to claim 1, wherein the packing density is a value obtained by dividing the cross-sectional area of ​​the membrane by the cross-sectional area of ​​the pot.

3. 2. The humidifier for a fuel cell according to claim 1, wherein the packing density is 0.51 or more.

4. 4. The humidifier for a fuel cell according to claim 1, wherein the packing density is 0.53 or less.

5. A cartridge for a fuel cell humidifier for humidifying dry gas supplied from an external source using wet gas discharged from a fuel cell stack, comprising: An inner case with both ends open, a hollow fiber membrane bundle housed in the inner case; an inner inlet and an inner outlet formed in the inner case and spaced apart from each other in a first axial direction; a first pot layer that fixes one end of the hollow fiber membrane bundle at one end of the inner case; a second pot layer that fixes the other end of the hollow fiber membrane bundle at the other end of the inner case, a packing density based on a pot cross-sectional area inside one end of the inner case where the first pot layer is potted and a membrane cross-sectional area of ​​the hollow fiber membrane bundle, in a second axis direction perpendicular to the first axis direction, of 0.405 to 0.625; A cartridge for a fuel cell humidifier, characterized in that when the width of the hollow fiber membrane bundle is taken as 1, the thickness of the hollow fiber membrane bundle is more than 0.2 and not more than 0.

6.

6. the membrane cross-sectional area is a value obtained by adding together the cross-sectional areas based on the outer diameters of the hollow fiber membranes of the hollow fiber membrane bundle, the pot cross-sectional area is a sum of the cross-sectional area of ​​the first pot layer and the cross-sectional area of ​​the membrane based on the second axial direction, 6. The cartridge for a fuel cell humidifier according to claim 5, wherein said packing density is a value obtained by dividing the cross-sectional area of ​​said membrane by the cross-sectional area of ​​said pot.

7. 6. The cartridge of claim 5, wherein the packing density is 0.51 or more.

8. 8. The cartridge of claim 5 or 7, wherein the packing density is 0.53 or less.

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