Mid-case of humidifier for fuel cell and humidifier for fuel cell

Abstract

The present invention relates to a mid-case of a humidifier for a fuel cell and a humidifier for a fuel cell, the mid-case including: a mid-body housing at least one cartridge including a plurality of hollow fiber membranes; a partition wall portion disposed inside the mid-body dividing the interior of the mid-body into an inflow space into which a first gas flows and an outflow space through which the first gas flows; and a bypass hole formed through the partition wall portion to allow a portion of the first gas flowing into the inflow space to bypass the cartridge and flow into the outflow space.

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 conventional chemical batteries such as dry batteries 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. In addition, because the chemical energy generated 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 that comes with 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), etc. Although each of these fuel cells operates on the same basic principle, they differ in the type of fuel used, operating temperature, catalyst, electrolyte, etc. Among these, polymer electrolyte membrane fuel cells (PEMFCs) are known to be the most promising, not only for small-scale stationary power generation devices, but also for transportation systems, because they operate at lower temperatures than other fuel cells, have a high power density, and can be made smaller. One of the most important factors in improving the performance of a polymer electrolyte fuel cell (PEMFC) is to maintain the moisture content by supplying a certain amount of moisture to the polymer electrolyte membrane (Polymer Electrolyte Membrane or Proton Exchange Membrane: PEM) of the membrane electrode assembly (Membrane Electrode Assembly: MEA). If the polymer electrolyte membrane dries out, the power generation efficiency drops sharply. Methods for humidifying a polymer electrolyte membrane include: 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 tube 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.

[0003] Among these, the membrane humidification method, which uses a membrane that selectively allows only water vapor contained in exhaust gas to pass through and provides water vapor to the air supplied to the polymer electrolyte membrane, thereby humidifying 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 a humidifier is manufactured using a hollow fiber membrane, it is possible to highly integrate hollow fiber membranes with a large contact surface area, so that it is possible to sufficiently humidify the fuel cell even with a small capacity, and it is possible to use low-cost materials. It is also possible to recover moisture and heat contained in the off-gas discharged at high temperature from the fuel cell and reuse it through the humidifier. FIG. 1 is a schematic exploded perspective view of a conventional fuel cell humidifier. 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 caps (120) attached to both ends of the humidification module (110). One of the caps (120) transfers air supplied from the outside to the humidification module (110), and the other transfers air humidified by the humidification module (110) to the fuel cell stack. 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) in the mid-case (111). Both ends of the 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 liquid polyurethane resin by 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 internal space of the cap (120) from the internal space of the mid-case (111). Similar to the fixing layer (113), the resin layer (114) is generally formed by curing a liquid polymer, such as a liquid polyurethane resin, through a casting method. Air supplied from the outside flows along the hollow of the hollow fiber membrane (112). Exhaust gas flowing into the mid-case (111) through the exhaust gas wet gas inlet (111a) comes into contact with the outer surface of the hollow fiber membrane (112) and then flows out of the mid-case (111) through the exhaust gas wet 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) to humidify the air flowing along the hollow of the hollow fiber membrane (112).

[0004] In this case, in the past, a shell differential pressure corresponding to the internal pressure of the mid-case (111) may increase while exhaust gas flows out of the mid-case (111) after flowing into the mid-case (111). When the shell differential pressure increases, there is a problem that the efficiency of the fuel cell system decreases, such as an increase in power consumption. This problem becomes more serious as the size of the fuel cell humidifier becomes smaller. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been devised to solve the above-mentioned problems, and aims to provide a mid-case of a humidifier for a fuel cell and a humidifier for a fuel cell that can reduce the shell differential pressure. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention can include the following configurations. The mid-case of the humidifier for fuel cells according to the present invention is provided in a humidifier for fuel cells, the mid-case including a humidification module that humidifies dry gas to be supplied to a fuel cell stack using wet gas, a first cap connected to one end of the humidification module, and a second cap connected to the other end of the humidification module, and includes a mid-case that houses at least one cartridge including a plurality of hollow fiber membranes; a partition portion that is disposed inside the mid-case and divides the inside of the mid-case into an inlet space into which a first gas flows and an outlet space from which the first gas flows out; and a bypass hole that is formed through the partition portion so that a portion of the first gas flowing into the inlet space bypasses the cartridge and flows to the outlet space. The humidifier for a fuel cell according to the present invention may include a humidification module for humidifying a dry gas to be supplied to a fuel cell stack using wet gas; 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 open ends, and at least one cartridge including a plurality of hollow fiber membranes. The mid-case may include a mid-body in which the cartridge is housed; a partition wall disposed inside the mid-body and dividing the interior of the mid-body into an inflow space into which a first gas is introduced and an outflow space into which the first gas is discharged; and a bypass hole formed through the partition wall so that a portion of the first gas introduced into the inflow space may bypass the cartridge and flow to the outflow space. Effect of the Invention

[0007] The present invention is embodied such that a portion of the first gas flowing into the inlet space bypasses the cartridge through the bypass hole and flows into the outlet space, thereby contributing to improving the efficiency of the fuel cell system by reducing the shell differential pressure using the bypass hole. The present invention can prevent the shell differential pressure from increasing excessively by using a bypass hole even if the size of the mid-case is reduced. Therefore, the present invention can improve versatility by being applicable to various applications such as hydrogen electric vehicles through miniaturization. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic exploded perspective view of a conventional humidifier for a fuel cell. [Diagram 2] 1 is a schematic exploded perspective view of a humidifier for a fuel cell according to the present invention; [Diagram 3] 3 is a schematic exploded cross-sectional view of the humidifier for a fuel cell according to the present invention taken along line II in FIG. 2. [Figure 4]3 is a schematic cross-sectional view of a humidifier for a fuel cell according to the present invention taken along line II in FIG. 2; [Diagram 5] 2 is a schematic plan view of a cartridge of a humidifier for a fuel cell according to the present invention; FIG. [Figure 6] 2 is a schematic plan view of a cartridge of a humidifier for a fuel cell according to the present invention; FIG. [Figure 7] 4 is a schematic side cross-sectional view showing a state in which an inlet space and an outlet space are partitioned by a partition in a mid-case of a humidifier for a fuel cell according to the present invention; FIG. [Figure 8] 8 is a schematic cross-sectional view taken along line II-II in FIG. 7. [Figure 9] 4 is a schematic side cross-sectional view showing a state in which a bypass hole is formed in a partition portion in a mid-case of a humidifier for a fuel cell according to the present invention; FIG. [Figure 10] 8 is a schematic cross-sectional view of a mid-case of a humidifier for a fuel cell according to a modified embodiment of the present invention taken along line II-II of FIG. 7. [Figure 11] These are the results of an experiment in which the cross-sectional area of ​​the inner surface of the compartment was fixed while only the cross-sectional area of ​​the bypass hole was changed, and the humidification efficiency and shell differential pressure were measured. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of a humidifier for a fuel cell according to the present invention will be described in detail with reference to the accompanying drawings. The mid-case 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, and will be described together with an embodiment of the humidifier for a fuel cell according to the present invention. Meanwhile, in Fig. 7 and Fig. 9, the hollow fiber membrane is simply shown by hatching, and the inner case is omitted. 2 to 4, the humidifier (1) for a fuel cell according to the present invention humidifies a dry gas to be supplied to a fuel cell stack (not shown) using a wet gas. The wet gas may be exhausted from the fuel cell stack. The dry gas may be a 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). 2 to 4, the humidification module (2) humidifies dry gas. The first cap (3) can be coupled to one end of the humidification module (2). The second cap (4) can be coupled to the other end of the humidification module (2). The humidification module (2) can supply humidified dry gas to the fuel cell stack using a first gas and a second gas. When the first gas is a dry gas, the second gas can be a wet gas. In this case, the first gas can be humidified by the second gas and then supplied to the fuel cell stack. When the first gas is a wet gas, the second gas can be a dry gas. In this case, the second gas can be humidified by the first gas and then supplied to the fuel cell stack. The humidification module (2) includes a mid-case (21) and at least one cartridge (22).

[0010] The mid-case (21) is connected to the cartridge (22). The cartridge (22) may be disposed inside the mid-case (21). The mid-case (21) has both ends open. In this case, a receiving hole (211) may be formed in the mid-case (21). The receiving hole (211) may be formed to penetrate the mid-case (21) in a first axis direction (X-axis direction). At least one cartridge (22) may be disposed in the receiving hole (211). The mid-case (21) may include a mid body (210). The mid body (210) accommodates the cartridge (22). The cartridge (22) may be accommodated in the mid body (210) by being disposed inside the mid body (210). At least one cartridge (22) may be accommodated in the mid body (210). The accommodation hole (211) may be formed penetrating the mid body (210) in the first axis direction (X-axis direction). The mid-case (21) may be formed with a first gas inlet (212) and a first gas outlet (213). The first gas inlet (212) may allow the first gas to flow into the mid body (210). The first gas outlet (213) may allow the first gas to flow out from the mid body (210). The first gas outlet (213) and the first gas inlet (212) may protrude from the mid body (210). The cartridge (22) is disposed inside the mid-case (21). The cartridge (22) includes a plurality of hollow fiber membranes (221). The hollow fiber membranes (221) can be coupled to the cartridge (22) to form a module. Thus, the hollow fiber membranes (221) can be installed inside the mid-case (21) through a process of coupling the cartridge (22) to the mid-case (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 membranes (221).

[0011] The cartridge (22) may include an inner case (222). The inner case (222) has openings at both ends and contains the hollow fiber membrane (221). The hollow fiber membrane (221) may be modularized by being disposed inside the inner case (222). The hollow fiber membrane (221) may include a polymer membrane made 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. The cartridge (22) may include a first fixing layer (223). The first fixing layer (223) fixes one end of the hollow fiber membrane (221). The first fixing layer (223) may close an opening formed at one end of the inner case (222). In this case, the first fixing layer (223) may be formed so as not to block the hollow of the hollow fiber membrane (221). The first fixing layer (223) may be formed by hardening a liquid resin such as a liquid polyurethane resin through a casting process. A part of the first fixing layer (223) may be located inside the inner case (222), and the remaining part may protrude outside the inner case (222). The first fixing layer (223) may fix one end of the hollow fiber membrane (221) to the inner case (222). The cartridge (22) may include a second fixing layer (224). The second fixing layer (224) fixes the other end of the hollow fiber membrane (221). The second fixing layer (224) may close an opening formed at the other end of the inner case (222). In this case, the second fixing layer (224) may be formed so as not to block the hollow of the hollow fiber membrane (221). The second fixing layer (224) may be formed by hardening a liquid resin such as a liquid polyurethane resin through a casting process. A part of the second fixing layer (224) may be located inside the inner case (222) and the remaining part may protrude outside the inner case (222). The second fixing layer (224) may fix the other end of the hollow fiber membrane (221) to the inner case (222). Since the second fixed layer (224) and the first fixed layer (223) are formed so as not to block the hollow of the hollow fiber membrane (221), the second gas can be supplied to the hollow of the hollow fiber membrane (221) without being obstructed by the second fixed layer (224) and the first fixed layer (223), and can flow out from the hollow of the hollow fiber membrane (221) without being obstructed by the second fixed layer (224) and the first fixed layer (223). Referring to Figures 2 to 6, the cartridge (22) can include a second gas inlet (225) and a second gas outlet (226).

[0012] The second gas inlet (225) is formed in the inner case (222). The second gas inlet (225) may be formed on one side of the inner case (222). One side of the inner case (222) may be disposed to face one of the side walls of the mid body (210). The second gas inlet (225) may allow the first gas to flow into the inner case (222). The second gas inlet (225) may be formed penetrating the inner case (222). As shown in FIG. 5, the second gas inlet (225) may be embodied as one through hole penetrating the inner case (222). As shown in FIG. 6, the second gas inlet (225) may be embodied as a plurality of through holes penetrating the inner case (222). In this case, the second gas inlet (225) may include a plurality of inlet windows (225a) formed to penetrate different portions of the inner case (222). The inlet windows (225a) may be arranged in a matrix form spaced apart from each other along the first axis direction (X-axis direction) and the second axis direction (Y-axis direction). The second axis direction (Y-axis direction) is perpendicular to the first axis direction (X-axis direction). The second gas outlet (226) is formed in the inner case (222). The second gas outlet (226) may be formed on one side of the inner case (222). The second gas outlet (226) may allow the first gas to flow out from inside the inner case (222). The second gas outlet (226) may be formed by penetrating the inner case (222). As shown in FIG. 5, the second gas outlet (226) may be implemented as one through-hole penetrating the inner case (222). As shown in FIG. 6, the second gas outlet (226) may be implemented as a plurality of through-holes penetrating the inner case (222). In this case, the second gas outlet (226) may include a plurality of outlet windows (226a) formed to penetrate different portions of the inner case (222). The outlet windows 226a may be spaced apart from each other in a matrix along the first axis direction (X-axis direction) and the second axis direction (Y-axis direction). The second gas outlet 226 and the second gas inlet 225 may be spaced apart from each other along the first axis direction (X-axis direction).

[0013] When the first gas is a wet gas, the first gas can be supplied between the inner surface of the mid-case (21) and the outer surface of the cartridge (22) through the first gas inlet (212), and can be supplied to the inside of the cartridge (22) through the second gas inlet (225) and can come into contact with the outer surface of the hollow fiber membrane (221). In this process, moisture contained in the first gas can permeate the hollow fiber membrane (221) to humidify the second gas flowing along the hollow of the hollow fiber membrane (221). After flowing out of the hollow fiber membrane (221), the humidified second gas can be supplied to the fuel cell stack through the first cap (3) or the second cap (4). The first gas after humidifying the second gas may be discharged between the outer surface of the cartridge 22 and the inner surface of the mid-case 21 through the second gas outlet 226, and may be discharged to the outside of the mid-case 21 through the first gas outlet 213. In this case, the first gas may be off-gas discharged from the fuel cell stack. When the first gas is a dry gas, the first gas may be supplied between the inner surface of the mid-case (21) and the outer surface of the cartridge (22) through the first gas inlet (212), and may be supplied into the cartridge (22) through the second gas inlet (225) to come into contact with the outer surface of the hollow fiber membrane (221). In this process, moisture in the second gas flowing along the hollow of the hollow fiber membrane (221) permeates the hollow fiber membrane (221) to humidify the first gas flowing into the cartridge (22). The humidified first gas may be discharged between the outer surface of the cartridge (22) and the inner surface of the mid-case (21) through the second gas outlet (226), and may be discharged to the outside of the mid-case (21) through the first gas outlet (213) to be supplied to the fuel cell stack. The second gas after humidifying the first gas may flow out of the hollow fiber membrane 221 and then be discharged to the outside through the first cap 3 or the second cap 4. In this case, the second gas may be off-gas discharged from the fuel cell stack.

[0014] The humidification module (2) may include a plurality of packing members (23, 23'). The packing members (23, 23') seal the gap between the cartridge (22) and the mid-case (21) so as to prevent the first gas and the second gas from being directly mixed. The packing members (23, 23') can be inserted between the cartridge (22) and the mid-case (21). In this case, the cartridge (22) can be inserted into the first through holes (23a, 23a') formed in the packing members (23, 23'). The packing members (23, 23') can be disposed on both ends of the cartridge (22). Although not shown, a resin layer can be formed on both ends of the cartridge (22) instead of the packing members (23, 23'). The resin layer can be formed by hardening a liquid polymer such as a liquid polyurethane resin by a casting method. 2 to 4, the first cap (3) is coupled to one end of the humidification module (2). The space between the first cap (3) and the cartridge (22) can be sealed from the space between the cartridge (22) and the mid-case (21) by the packing member (23) or a resin layer. The first cap (3) can include a first port (31). The first port (31) is for the second gas to flow through. The first port (31) can be in communication with the hollow fiber membrane (221). In this way, in the process of the second gas flowing between the first cap (3) and the hollow fiber membrane (221), the second gas can flow in or out through the first port (31). 2 to 4, the second cap (4) is coupled to the other end of the humidification module (2). The second cap (4) may be coupled to the other end of the humidification module (2) at a position spaced apart from the first cap (3) along the first axis direction (X-axis direction). The space between the second cap (4) and the cartridge (22) may be sealed against the space between the cartridge (22) and the mid-case (21) by the packing member (23') or a resin layer. The second cap (4) may include a second port (41). The second port (41) is for the second gas to flow through. The second port (41) may be in communication with the hollow fiber membrane (221). In this way, during the process in which the second gas flows between the second cap (4) and the hollow fiber membrane (221), the second gas may flow in or out through the second port (41). When the second gas flows in through the second port (41), the second gas can flow out through the first port (31). In this case, the second gas can exchange moisture with the first gas while passing through the second cap (4), the hollow of the hollow fiber membrane (221), and the first cap (3) in sequence. When the second gas flows out through the second port (41), the second gas can flow in through the first port (31). In this case, the second gas can exchange moisture with the first gas while passing through the first cap (3), the hollow of the hollow fiber membrane (221), and the second cap (4) in sequence.

[0015] Here, the humidifier (1) for a fuel cell according to the present invention may be embodied to prevent an excessive increase in shell differential pressure, which corresponds to the internal pressure of the mid-case (21), while the first gas flows into the mid-case (21) through the first gas inlet (212) and then flows out of the mid-case (21) through the first gas outlet (213). To this end, the mid-case (21) may be embodied as follows. 2 to 8, the mid-case (21) may include a partition (214). The partition wall portion (214) is disposed inside the mid body (210). The partition wall portion (214) may divide the inside of the mid body (210) into an inflow space (214a) and an outflow space (214b). The inflow space (214a) is a space into which the first gas is introduced and may be connected to the first gas inlet (212). The inflow space (214a) may be disposed between the packing member (23) and the partition wall portion (214) based on the first axis direction (X-axis direction). The outflow space (214b) is a space into which the first gas is discharged and may be connected to the first gas outlet (213). The outflow space (214b) may be disposed between the partition wall portion (214) and the packing member (23') based on the first axis direction (X-axis direction). The partition wall (214) is disposed between the inflow space (214a) and the outflow space (214b) to prevent the first gas flowing into the inflow space (214a) through the first gas inlet (212) from flowing directly into the outflow space (214b) without passing through the inside of the cartridge (22). Thus, the humidifier (1) for a fuel cell according to the present invention can improve humidification efficiency by increasing the flow rate of the first gas flowing into the inside of the cartridge (22). The partition wall portion (214) may be coupled to the mid body (210) so as to block the compartment inner surface (210a) of the mid body (210). The compartment inner surface (210a) may correspond to the inner surface of the mid body (210) on which the partition wall portion (214) is disposed. The compartment inner surface (210a) and the partition wall portion (214) may be disposed between the first gas inlet (212) and the first gas outlet (213) based on the first axis direction (X-axis direction). The compartment inner surface (210a) and the partition wall portion (214) may be disposed at a position spaced apart from the first gas inlet (212) and the first gas outlet (213) by the same distance based on the first axis direction (X-axis direction). The partition wall portion (214) and the mid body (210) may be formed integrally. In this case, the partition wall portion (214) may be formed so as to protrude from the compartment inner surface (210a) toward the inside of the mid body (210).

[0016] 2 to 9, the mid-case (21) may include a bypass hole (215). The bypass hole (215) is formed to penetrate the partition wall portion (214). A portion of the first gas flowing into the inflow space (214a) through the bypass hole (215) can bypass the cartridge (22) and flow into the outflow space (214b). That is, a portion of the first gas can flow directly from the inflow space (214a) to the outflow space (214b) without passing through the inside of the cartridge (22). As a result, the humidifier (1) for a fuel cell according to the present invention can achieve the following effects. First, without the bypass hole 215, the first gas flowing into the inlet space 214a cannot flow into the outlet space 214b without passing through the inside of the cartridge 22. As a result, when the flow rate of the first gas residing inside the mid-case 21 increases, such as when the flow rate of the first gas flowing into the inlet space 214a increases or the flow rate of the first gas flowing out of the outlet space 214b decreases, the shell differential pressure increases. The increase in shell differential pressure may increase power consumption and reduce the efficiency of the fuel cell system. In addition, the decrease in efficiency of the fuel cell system due to the increase in shell differential pressure becomes more serious as the mid-case 21 becomes smaller. Therefore, without the bypass hole 215, it is difficult to reduce the overall size. Next, when the bypass hole (215) is present, a portion of the first gas flowing into the inlet space (214a) can bypass the cartridge (22) through the bypass hole (215) and flow into the outlet space (214b). That is, a portion of the first gas can flow directly from the inlet space (214a) to the outlet space (214b) without passing through the inside of the cartridge (22) through the bypass hole (215). As a result, the humidifier (1) for a fuel cell according to the present invention can reduce the shell differential pressure using the bypass hole (215), thereby contributing to improving the efficiency of the fuel cell system. In addition, the humidifier (1) for a fuel cell according to the present invention can prevent an excessive increase in the shell differential pressure using the bypass hole (215) even if the size of the mid-case (21) is reduced, thereby improving versatility that can be applied to various applications such as hydrogen electric vehicles by implementing a compact size.

[0017] The bypass hole (215) can pass a part of the first gas flowing into the inflow space (214a) through the first gas inlet (212) to the outflow space (214b). The first gas flowing into the outflow space (214b) through the bypass hole (215) can be discharged to the outside of the mid-case (21) through the first gas outlet (213). In FIG. 8, the bypass hole (215) is illustrated as having a triangular cross section, but is not limited thereto. The bypass hole (215) can be formed in various shapes, such as a polygonal cross section such as a square cross section, a circular cross section, etc., as long as the first gas can pass from the inflow space (214a) to the outflow space (214b). 2 to 10, the bypass hole (215) may be formed penetrating the partition wall (214) so ​​as to be disposed between an upper surface (210b) of the mid body (210) and a bottom surface (210c) of the mid body (210). At least one of the first gas inlet (212) and the first gas outlet (213) may be disposed on the upper surface (210b) of the mid body (210). The bottom surface (210c) of the mid body (210) may be disposed opposite to the upper surface (210b) of the mid body (210). The bottom surface (210c) of the mid body (210) may be disposed on a side in a direction in which gravity acts. As shown in FIG. 9, the bypass hole (215) may be disposed at a position closer to the top surface (210b) of the mid body (210) than to the bottom surface (210c) of the mid body (210). 10, the bypass hole (215) may be disposed at a position closer to the bottom surface (210c) of the mid body (210) than to the top surface (210b) of the mid body (210). In this case, the bypass hole (215) can discharge condensed water present on the bottom surface (210c) of the mid body (210) to the outflow space (214b). Condensed water is generated during the moisture exchange between the first gas and the second gas, and may accumulate on the bottom surface (210c) of the mid body (210) due to gravity. If the flow rate of the condensed water supplied to the fuel cell stack increases, the efficiency of the fuel cell system may decrease due to a flooding phenomenon, so the humidifier (1) for a fuel cell according to the present invention is embodied to discharge the condensed water to the outflow space (214b) using the bypass hole (215) and then discharge the condensed water to the outside of the mid-case (21) through the first gas outlet (213). Therefore, the humidifier (1) for a fuel cell according to the present invention can contribute to improving the efficiency of the fuel cell system by discharging the condensed water using the bypass hole (215).

[0018] 2 to 11, the cross-sectional area of ​​the bypass hole (215) may be determined according to the cross-sectional area of ​​the partition inner surface (210a). In this case, the cross-sectional area may correspond to the area of ​​a cross section based on an axial direction perpendicular to the direction in which the inflow space (214a) and the outflow space (214b) are separated from each other. The direction in which the inflow space (214a) and the outflow space (214b) are separated from each other may be parallel to the first axial direction (X-axis direction). The cross-sectional area may be the area of ​​a cross section based on the second axial direction (Y-axis direction). When the cross-sectional area of ​​the partition inner surface (210a) is 1, the cross-sectional area of ​​the bypass hole (215) may be embodied as 0.005 to 0.1. That is, the cross-sectional area of ​​the bypass hole (215) with respect to the cross-sectional area of ​​the partition inner surface (210a) may be 0.5% to 10%. Therefore, the humidifier for a fuel cell (1) according to the present invention is embodied to have a humidification efficiency and a shell differential pressure within a predetermined range, thereby contributing to improving the efficiency of the fuel cell system. It can be confirmed from the experimental result of Fig. 11 that when the cross-sectional area of ​​the bypass hole (215) to the cross-sectional area of ​​the compartment inner surface (210a) is 0.5% to 10%, the humidification efficiency and shell differential pressure are within a predetermined range. Fig. 11 shows the experimental result of measuring the humidification efficiency and shell differential pressure when only the cross-sectional area of ​​the bypass hole (215) is changed while the cross-sectional area of ​​the compartment inner surface (210a) is fixed. In Fig. 11, the cross-sectional area ratio means the cross-sectional area ratio of the bypass hole (215) to the cross-sectional area of ​​the compartment inner surface (210a).

[0019] 11, in Example 1, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 0.5%, and the humidification efficiency is 25.0RH% and the shell differential pressure is 20kPa. In Example 2, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 1.8%, and the humidification efficiency is 24.3RH% and the shell differential pressure is 18kPa. In Example 3, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 3.6%, and the humidification efficiency is 24.0RH% and the shell differential pressure is 14kPa. In Example 4, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 10.0%, and the humidification efficiency is 23.0 RH% and the shell differential pressure is 10 kPa. As described above, in Examples 1 to 4, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 0.5% to 10%, and thus the humidification efficiency is 23 RH% to 24.5 RH% and the shell differential pressure is 10 kPa to 20 kPa. In contrast, Comparative Example 1 does not have the bypass hole (215) and has a humidification efficiency of 25.0 RH%, but a significantly high shell differential pressure of 30 kPa. In comparison with Example 1, in which the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 0.5%, Comparative Example 1 has a significantly increased shell differential pressure despite no significant difference in humidification efficiency. As a result, Comparative Example 1 is found to have a lower efficiency of the fuel cell system than Example 1. In addition, in Comparative Example 2, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 11.0%, and the humidification efficiency is 22.0 RH% and the shell differential pressure is 10 kPa. In Comparative Example 2, the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the compartment inner surface (210a) is 10.0%, and the humidification efficiency is reduced by 1.0 RH% even though there is no difference in the shell differential pressure. Thus, in Comparative Example 2, only the humidification efficiency is reduced compared to Example 4, and therefore the performance of the fuel cell system is degraded. In this manner, the humidifier (1) for fuel cell according to the present invention is embodied such that the cross-sectional area of ​​the bypass hole (215) relative to the cross-sectional area of ​​the partition inner surface (210a) is 0.5% to 10%, thereby exhibiting a humidification efficiency of 23RH% to 24.5RH% and a shell differential pressure of 10kPa to 20kPa. Therefore, the humidifier (1) for fuel cell according to the present invention can smoothly supply humidified gas to the fuel cell stack, thereby improving the performance of the fuel cell system, as well as contributing to improving the efficiency of the fuel cell system through a reduction in the shell differential pressure.

[0020] Assuming that the cross-sectional area of ​​the compartment inner surface (210a) is 1, the cross-sectional area of ​​the bypass hole (215) may be 0.005 to 0.06. That is, the cross-sectional area of ​​the bypass hole (215) with respect to the cross-sectional area of ​​the compartment inner surface (210a) may be 0.5% to 6%. Assuming that the cross-sectional area of ​​the compartment inner surface (210a) is 1, the cross-sectional area of ​​the bypass hole (215) may be 0.005 to 0.04. That is, the cross-sectional area of ​​the bypass hole (215) with respect to the cross-sectional area of ​​the compartment inner surface (210a) may be 0.5% to 4%. A plurality of the bypass holes (215) may be formed in the partition wall portion (214). The bypass holes (215, 215') may be formed to penetrate the partition wall portion (214) at positions spaced apart from each other. Thus, the humidifier (1) for a fuel cell according to the present invention is embodied to be capable of bypassing the first gas at different positions of the partition wall portion (214). In this case, the sum of the cross-sectional areas of the bypass holes (215, 215') may be 0.005 to 0.1, assuming that the cross-sectional area of ​​the partition inner surface (210a) is 1. That is, the sum of the cross-sectional areas of the bypass holes (215, 215') with respect to the cross-sectional area of ​​the partition inner surface (210a) may be 0.5% to 10%. 10 shows that all of the bypass holes (215, 215') are disposed at a position closer to the bottom surface (210c) of the mid body (210) than the top surface (210b) of the mid body (210), but is not limited thereto, and all of the bypass holes (215, 215') may be disposed at a position closer to the top surface (210b) of the mid body (210) than the bottom surface (210c) of the mid body (210). Some of the bypass holes (215, 215') may be disposed closer to the bottom surface (210c) of the mid body (210), and some of the bypass holes (215, 215') may be disposed closer to the top surface (210b) of the mid body (210). In addition, although FIG. 10 illustrates two bypass holes (215, 215') formed in the partition wall portion (214), the present invention is not limited thereto, and three or more bypass holes (215) may be formed in the partition wall portion (214). 2 to 10, the mid-case (21) may include an insertion hole (216).

[0021] The insertion hole (216) is formed to penetrate the partition part (214). The cartridge (22) can be inserted into the insertion hole (216). The partition part (214) supports the cartridge (22) inserted into the insertion hole (216), thereby coupling the cartridge (22) to the mid body (210). The cartridge (22) can be inserted into the insertion hole (216) in an interference fit manner. The insertion hole (216) and the bypass hole (215) can be formed to penetrate the partition part (214) at positions spaced apart from each other. The mid-case (21) may include a plurality of the insertion holes (216). The insertion holes (216, 216', 216") may be formed at positions spaced apart from each other to penetrate the partition portion (214). As a result, the humidifier (1) for a fuel cell according to the present invention is realized to be capable of housing a plurality of cartridges (22) in the mid-case (21). FIG. 8 illustrates two insertion holes (216, 216') formed in the partition portion (214), and FIG. 10 illustrates three insertion holes (216, 216', 216") formed in the partition portion (214), but is not limited thereto, and four or more insertion holes (216) may be formed in the partition portion (214). The present invention described above is not limited to the above-mentioned embodiments and the accompanying drawings, and it will be apparent to those having ordinary skill 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 mid-case provided in a humidifier for a fuel cell, the mid-case including a humidification module for humidifying dry gas to be supplied to a fuel cell stack using wet gas, a first cap coupled to one end of the humidification module, and a second cap coupled to the other end of the humidification module, a mid-body housing at least one cartridge including a plurality of hollow fiber membranes; a partition disposed inside the mid body and dividing the inside of the mid body into an inflow space into which a first gas flows and an outflow space through which the first gas flows; and a bypass hole formed through the partition so that a portion of the first gas flowing into the inlet space can bypass the cartridge and flow to the outlet space.

2. The mid-case includes an insertion hole formed through the partition, The cartridge is inserted into the insertion hole, 2. The mid-case of the humidifier for a fuel cell according to claim 1, wherein the bypass hole and the insertion hole are formed at positions spaced apart from each other and penetrating the partition.

3. The partition is coupled to the mid body so as to block an inner partition surface of the mid body, 2. The mid-case of the fuel cell humidifier according to claim 1, wherein the cross-sectional area of ​​the bypass hole is 0.005 to 0.1, where the cross-sectional area of ​​the inner surface of the compartment is 1.

4. The partition portion has a plurality of bypass holes formed therein, 2. The mid-case of the humidifier for a fuel cell according to claim 1, wherein the bypass holes are formed at positions spaced apart from each other and penetrating the partition wall.

5. The partition is coupled to the mid body so as to block an inner partition surface of the mid body, A mid-case of a humidifier for a fuel cell as described in claim 4, characterized in that when the cross-sectional area of ​​the inner surface of the partition is 1, the sum of the cross-sectional areas of the bypass holes is 0.005 or more and 0.1 or less.

6. the mid-case includes a first gas inlet for introducing a first gas into the inlet space and a first gas outlet for discharging the first gas from the outlet space; 2. The mid-case of the humidifier for a fuel cell according to claim 1, wherein the bypass hole allows a portion of the first gas flowing into the inlet space through the first gas inlet to pass to the outlet space.

7. The mid-case of the humidifier for a fuel cell according to claim 1, wherein the bypass hole is disposed at a position spaced closer from a bottom surface of the mid body than from a top surface of the mid body, and discharges condensed water present on the bottom side of the mid body to the outflow space.

8. a humidification module for humidifying the dry gas supplied to the fuel cell stack using the humidified gas; 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 includes a mid-case having both open ends and at least one cartridge including a plurality of hollow fiber membranes; The mid-case is a mid-body in which the cartridge is housed; a partition disposed inside the mid body and dividing the inside of the mid body into an inflow space into which a first gas flows and an outflow space through which the first gas flows; and a bypass hole formed through the partition so that a portion of the first gas flowing into the inlet space can bypass the cartridge and flow to the outlet space.

9. The mid-case includes an insertion hole formed through the partition, The cartridge is inserted into the insertion hole, 9. The humidifier for a fuel cell according to claim 8, wherein the bypass hole and the insertion hole are formed at positions spaced apart from each other through the partition wall.

10. The partition is coupled to the mid body so as to block an inner partition surface of the mid body, 9. The humidifier for a fuel cell according to claim 8, wherein the cross-sectional area of ​​the bypass hole is 0.005 or more and 0.1 or less, assuming that the cross-sectional area of ​​the inner surface of the compartment is 1.

11. The partition portion has a plurality of bypass holes formed therein, 9. The humidifier for a fuel cell according to claim 8, wherein the bypass holes are formed at positions spaced apart from each other and penetrating the partition wall.

12. The partition is coupled to the mid body so as to block an inner partition surface of the mid body, 12. The humidifier for a fuel cell according to claim 11, wherein when the cross-sectional area of ​​the partition inner surface is taken as 1, the sum of the cross-sectional areas of the bypass holes is 0.005 or more and 0.1 or less.

13. the mid-case includes a first gas inlet for introducing a first gas into the inlet space and a first gas outlet for discharging the first gas from the outlet space; 9. The humidifier for a fuel cell according to claim 8, wherein the bypass hole allows a portion of the first gas flowing into the inflow space through the first gas inlet to pass to the outflow space.

14. 9. The humidifier for a fuel cell as described in claim 8, wherein the bypass hole is disposed at a position spaced closer from a bottom surface of the mid body than from a top surface of the mid body, and discharges condensed water present on the bottom side of the mid body to the outflow space.

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