Mid-case and fuel cell humidifier

Abstract

A mid-body that houses at least one cartridge containing a plurality of hollow fiber membranes; and a bypass portion that bypasses a first gas flowing in through a first gas inlet of a first cap and allows the first gas to flow into a cartridge side housed inside the mid-body, the bypass portion including a mid-case of a fuel cell humidifier and a fuel cell humidifier that protrude from the mid-body at a position overlapping the cartridge housed inside the mid-body.

Description

Technical Field

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

Background Art

[0002] Unlike general chemical batteries such as dry batteries and storage batteries, a fuel cell can continue to produce electricity as long as hydrogen and oxygen are supplied, and since there is no heat loss, it has an advantage of being about twice as efficient as an internal combustion engine. In addition, since chemical energy generated by the combination of hydrogen and oxygen is directly converted into electrical energy, there is little emission of pollutants. Therefore, a fuel cell has an advantage that it is not only environmentally friendly but also can reduce concerns about resource depletion associated with an increase in energy consumption. Such fuel cells can be broadly classified into Polymer Electrolyte Membrane Fuel Cell (PEMFC), Phosphoric Acid Fuel Cell (PAFC), Molten Carbonate Fuel Cell (MCFC), Solid Oxide Fuel Cell (SOFC), and Alkaline Fuel Cell (AFC) according to the type of electrolyte used. Each of these fuel cells operates based on basically the same principle, but the types of fuels used, operating temperatures, catalysts, electrolytes, etc. are different from each other. Among these, the Polymer Electrolyte Membrane Fuel Cell (PEMFC) is known to be the most promising not only as a small-scale stationary power generation device but also as a transportation system because it operates at a lower temperature compared to other fuel cells and has a high output density and can be miniaturized. One of the most important factors in improving the performance of polymer electrolyte fuel cells (PEMFCs) is maintaining a certain level of moisture content in the polymer electrolyte membrane (PEM) of the membrane electrode assembly (MEA). This is because the power generation efficiency drops sharply when the polymer electrolyte membrane dries out. Methods for humidifying polymer electrolyte membranes include: 1) the bubbler humidification method, which involves filling a pressure vessel with water and then passing the target gas through a diffuser to supply moisture; 2) the direct injection method, which calculates the amount of moisture required for the fuel cell reaction and supplies moisture directly to the gas flow pipe through a solenoid valve; and 3) the humidification membrane method, which uses a polymer separation membrane to supply moisture to the gas fluid bed. Among these methods, the membrane humidification method, which uses a membrane that selectively allows only water vapor contained in the exhaust gas to pass through, and provides water vapor to the air supplied to the polymer electrolyte membrane, is advantageous in that it allows for a lighter and more compact humidifier. When forming modules, hollow fiber membranes with a large permeable area per unit volume are preferred as selective permeable membranes used in membrane humidification systems. In other words, when manufacturing humidifiers using hollow fiber membranes, it is possible to integrate a large number of hollow fiber membranes with a large contact surface area, which allows for sufficient humidification of fuel cells even in small capacities, enables the use of low-cost materials, and has the advantage of recovering moisture and heat contained in the exhaust gas (off-gas) discharged at high temperatures from fuel cells and reusing it through the humidifier. Figure 1 is a schematic exploded perspective view of a typical fuel cell humidifier. As illustrated in Figure 1, a typical membrane humidifier (100) includes a humidification module (110) in which moisture exchange takes place between air supplied from the outside and exhaust gas discharged from a fuel cell stack (not shown), and caps (120) coupled to both ends of the humidification module (110). One of the caps (120) transmits air supplied from the outside to the humidification module (110), and the other transmits the air humidified by the humidification module (110) to the fuel cell stack.

[0003] 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 hollow fiber membranes (112) are potted in a fixed layer (113). The fixed layer (113) is generally formed by curing a liquid polymer, such as liquid polyurethane resin, using a casting method. The fixed layer (113) to which the ends of the hollow fiber membranes (112) are potted, and the resin layer (114) between the fixed 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 fixed layer (113), the resin layer (114) is generally formed by curing a liquid polymer, such as liquid polyurethane resin, using a casting method. Air supplied from the outside flows along the hollow of the hollow fiber membrane (112). Exhaust gas that flows into the mid-case (111) through the exhaust gas moist 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 moist gas outlet (111b). When the exhaust gas comes into contact with the outer surface of the hollow fiber membrane (112), the moisture contained in the exhaust gas permeates through the hollow fiber membrane (112), thereby humidifying the air that was flowing along the hollow of the hollow fiber membrane (112). In this case, conventionally, the exhaust gas flowing into the mid-case (111) flowed toward the hollow fiber membrane (112). As a result, conventionally, the pressure of the exhaust gas flowing into the mid-case (111) was directly applied to the hollow fiber membrane (112), which caused damage or breakage of the hollow fiber membrane (112). [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The present invention was devised to solve the aforementioned problems and aims to provide a mid-case for a fuel cell humidifier and a fuel cell humidifier that can reduce damage or breakage occurring in the hollow fiber membrane. [Means for solving the problem]

[0005] To solve the aforementioned problems, the present invention may include the following configuration. The mid-case of the fuel cell humidifier according to the present invention is provided in a fuel cell humidifier that includes a humidification module for humidifying dry gas supplied to a fuel cell stack using a 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, and may include a mid-body that houses at least one cartridge containing a plurality of hollow fiber membranes; and a bypass section that diverts the first gas flowing in through the first gas inlet of the first cap and directs it to the cartridge housed inside the mid-body. The bypass section may protrude from the mid-body at a position that overlaps with the cartridge housed inside the mid-body. The fuel cell humidifier according to the present invention may include a humidification module for humidifying dry gas supplied to a fuel cell stack using a 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 may include a mid-case with both ends open, and at least one cartridge containing a plurality of hollow fiber membranes. The first cap may include a first gas inlet through which a first gas for supply to the interior of the mid-case flows in, and a first port communicating with the hollow fiber membranes through which a second gas flows in or out. The mid-case may include a mid-body in which the cartridge is housed, and a bypass section that diverts the first gas flowing in through the first gas inlet and directs it towards the cartridge housed inside the mid-body. The bypass section may protrude from the mid-body at a position overlapping with the cartridge housed inside the mid-body. [Effects of the Invention]

[0006] This invention can reduce the risk of damage or breakage of hollow fiber membranes due to gas pressure. Therefore, this invention can extend the service life and reduce maintenance costs. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic exploded perspective view of a typical fuel cell humidifier. [Figure 2] This is a schematic exploded perspective view of a fuel cell humidifier according to the present invention. [Figure 3] This is a schematic exploded cross-sectional view of the fuel cell humidifier according to the present invention, shown with respect to line II in Figure 2. [Figure 4] This is a schematic coupled cross-sectional view of the fuel cell humidifier according to the present invention, shown with respect to line II in Figure 2. [Figure 5] This is a schematic plan view of the cartridge of a fuel cell humidifier according to the present invention. [Figure 6]This is a schematic plan view of the cartridge of a fuel cell humidifier according to the present invention. [Figure 7] This is a schematic side cross-sectional view showing how the first gas, which flows into the mid-case through the first gas inlet, immediately flows towards the cartridge. [Figure 8] This is a schematic perspective view of a fuel cell humidifier according to the present invention, including a bypass section. [Figure 9] This is a schematic partial cross-sectional view shown with reference to line II-II in Figure 8. [Figure 10] This is a schematic exploded perspective view of a fuel cell humidifier according to the present invention, comprising a mid-case having a bypass section and a first cap having a first gas inlet. [Figure 11] This is the experimental result of measuring humidification efficiency and shell differential pressure by changing the cross-sectional area of ​​the first bypass passage. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the fuel cell humidifier according to the present invention will be described in detail with reference to the attached drawings. The mid-case of the fuel cell humidifier according to the present invention can be included in the fuel cell humidifier according to the present invention, and will be described together with the embodiments of the fuel cell humidifier according to the present invention. On the other hand, in Figure 7, the two parallel curves are omitted lines. Also, in Figures 7 and 9, the hollow fiber membrane is simply shown with hatching, and the inner case is omitted. Referring to Figures 2 to 4, the fuel cell humidifier (1) according to the present invention humidifies dry gas supplied to a fuel cell stack (not shown) using a humid gas. The humid gas may be discharged from the fuel cell stack. The dry gas may be fuel gas or air. The dry gas can be supplied to the fuel cell stack after being humidified by the humid gas. The fuel cell humidifier (1) 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). Referring to Figures 2 to 4, the humidification module (2) humidifies dry gas. The first cap (3) can be connected to one end of the humidification module (2). The second cap (4) can be connected to the other end of the humidification module (2). The humidification module (2) can supply humidified dry gas to the fuel cell stack using the first gas and the second gas. When the first gas is dry gas, the second gas may be a humid gas. In this case, the first gas can be supplied to the fuel cell stack after being humidified by the second gas. When the first gas is a humid gas, the second gas may be dry gas. In this case, the second gas can be supplied to the fuel cell stack after being humidified by the first gas. The humidification module (2) includes a mid-case (21) and at least one cartridge (22). The mid-case (21) is into which the cartridge (22) is coupled. The cartridge (22) can be placed inside the mid-case (21). The mid-case (21) is open at both ends. In this case, a housing hole (211) can be formed in the mid-case (21). The housing hole (211) can be formed to penetrate the mid-case (21) in the first axial direction (X-axis direction). At least one cartridge (22) can be placed in the housing hole (211). The mid-case (21) may include a mid-body (210). The mid-body (210) houses the cartridge (22). The cartridge (22) can be housed in the mid-body (210) by being positioned inside the mid-body (210). The mid-body (210) can house at least one cartridge (22). The housing hole (211) may be formed to penetrate the mid-body (210) in the first axial direction (X-axis direction).

[0009] A first gas inlet (30) and a first gas outlet (212) can be formed in the mid-case (21). The first gas inlet (30) allows the first gas to flow into the interior of the mid-case (21). The first gas outlet (212) allows the first gas to flow out from the interior of the mid-case (21). In this case, the first gas outlet (212) allows the first gas that has flowed out from the cartridge (22) to flow out of the mid-case 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, through the process of coupling the cartridge (22) to the mid-case (21), the hollow fiber membranes (221) can be installed inside the mid-case (21). Therefore, the fuel cell humidifier (1) according to the present invention can improve the ease of installation, separation, and replacement of the hollow fiber membranes (221). 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) can be modularized by being arranged inside the inner case (222). The hollow fiber membrane (221) may include a polymer membrane formed from 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) can 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) can close an opening formed at one end of the inner case (222). In this case, the first fixing layer (223) can be formed so as not to block the hollow of the hollow fiber membrane (221). The first fixing layer (223) can be formed by curing a liquid resin such as a liquid polyurethane resin through a casting process. A part of the first fixing layer (223) can be located inside the inner case (222), and the remaining part can protrude outside the inner case (222). The first fixing layer (223) can also fix one end of the hollow fiber membrane (221) and the inner case (222).

[0010] The cartridge (22) can 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) can close an opening formed at the other end of the inner case (222). In this case, the second fixing layer (224) can be formed so as not to block the hollow of the hollow fiber membrane (221). The second fixing layer (224) can be formed by curing a liquid resin such as a liquid polyurethane resin through a casting process. A part of the second fixing layer (224) can be located inside the inner case (222), and the remaining part can protrude outside the inner case (222). The second fixing layer (224) can also fix the other end of the hollow fiber membrane (221) and the inner case (222). Since the second fixing layer (224) and the first fixing 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 fixing layer (224) and the first fixing layer (223), and can flow out from the hollow of the hollow fiber membrane (221) without being obstructed by the second fixing layer (224) and the first fixing layer (223). Referring to Figures 2 to 6, the cartridge (22) may include a second gas inlet (225) and a second gas outlet (226). The second gas inlet (225) is formed in the inner case (222). The second gas inlet (225) can be formed on one side of the inner case (222). The one side of the inner case (222) can be positioned to face one of the side walls of the mid-body (210). The second gas inlet (225) allows the first gas to flow into the interior of the inner case (222). The second gas inlet (225) can be formed by penetrating the inner case (222). As shown in Figure 5, the second gas inlet (225) can be realized as a single through-hole penetrating the inner case (222). As shown in Figure 6, the second gas inlet (225) can also be realized 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 configuration, spaced apart from each other along the first axial direction (X-axis direction) and the second axial direction (Y-axis direction). The second axial direction (Y-axis direction) is an axial direction perpendicular to the first axial direction (X-axis direction).

[0011] The second gas outlet (226) is formed in the inner case (222). The second gas outlet (226) can be formed on one side of the inner case (222). The second gas outlet (226) can allow the first gas to flow out from inside the inner case (222). The second gas outlet (226) can be formed by penetrating the inner case (222). As shown in Figure 5, the second gas outlet (226) can be represented by a single through-hole penetrating the inner case (222). As shown in Figure 6, the second gas outlet (226) can also be represented by a plurality of through-holes penetrating the inner case (222). In this case, the second gas outlet (226) can include a plurality of outlet windows (226a) formed to penetrate different parts of the inner case (222). The outflow windows (226a) can be arranged in a matrix configuration, spaced apart from each other along the first axial direction (X-axis direction) and the second axial direction (Y-axis direction). The second gas outlet (226) and the second gas inlet (225) can be positioned at locations spaced apart from each other along the first axial direction (X-axis direction). When the first gas is a humid gas, the first gas is supplied between the inner surface of the mid-case (21) and the outer surface of the cartridge (22) through the first gas inlet (30), and is supplied into the cartridge (22) through the second gas inlet (225), and can contact the outer surface of the hollow fiber membrane (221). In this process, the moisture contained in the first gas permeates through the hollow fiber membrane (221), so that the second gas flowing along the hollow of the hollow fiber membrane (221) can be humidified. After the humidified second gas flows out of the hollow fiber membrane (221), it 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 flows out between the outer surface of the cartridge (22) and the inner surface of the mid-case (21) through the second gas outlet (226), and can flow out of the mid-case (21) through the first gas outlet (212). In this case, the first gas can be off-gas discharged from the fuel cell stack. If the first gas is a dry gas, the first gas is supplied through the first gas inlet (30) between the inner surface of the mid-case (21) and the outer surface of the cartridge (22), and 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 from the second gas flowing along the hollow of the hollow fiber membrane (221) permeates through the hollow fiber membrane (221), thereby humidifying the first gas that has flowed into the inside of the cartridge (22). The humidified first gas flows out through the second gas outlet (226) between the outer surface of the cartridge (22) and the inner surface of the mid-case (21), and flows out to the outside of the mid-case (21) through the first gas outlet (212), after which it can be supplied to the fuel cell stack. The second gas, after humidifying the first gas, can be discharged to the outside through the first cap (3) or the second cap (4) after flowing out of the hollow fiber membrane (221). In this case, the second gas may be the exhaust gas (off-gas) discharged from the fuel cell stack. The humidification module (2) may include a plurality of packing members (23, 23').

[0012] The packing members (23, 23') seal the space between the cartridge (22) and the mid-case (21) to prevent the first gas and the second gas from directly mixing. 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 each be positioned on both sides of the cartridge (22). Although not shown, instead of the packing members (23, 23'), resin layers can also be formed on both sides of the cartridge (22). The resin layers can be formed by curing a liquid polymer, such as liquid polyurethane resin, by a casting method. Referring to Figures 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 resin layer. The first cap (3) may include a first port (31). The first port (31) is for the flow of the second gas. The first port (31) can communicate with the hollow fiber membrane (221). As a result, 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). Referring to Figures 2 to 4, the second cap (4) is coupled to the other end of the humidification module (2). The second cap (4) can be coupled to the other end of the humidification module (2) at a position separated from the first cap (3) along the first axial direction (X-axis direction). The space between the second cap (4) 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 the resin layer. The second cap (4) may include a second port (41). The second port (41) is for the flow of the second gas. The second port (41) can communicate with the hollow fiber membrane (221). As a result, in the process of the second gas flowing between the second cap (4) and the hollow fiber membrane (221), the second gas can 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 as it passes sequentially through the second cap (4), the hollow fiber membrane (221), and the first cap (3). 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 as it passes sequentially through the first cap (3), the hollow fiber membrane (221), and the second cap (4). Here, as shown in Figure 7, if the first gas flowing into the mid-case (21) through the first gas inlet (30) flows immediately to the cartridge (22), there is a risk that the hollow fiber membrane (221) will be damaged or broken due to the pressure of the first gas. To prevent this, the fuel cell humidifier (1) according to the present invention can be implemented such that the first gas flowing in through the first gas inlet (30) bypasses the first gas and flows to the cartridge (22). For this reason, in the fuel cell humidifier (1) according to the present invention, the mid-case (21) and the first cap (3) can be implemented as follows. Referring to Figures 2 to 10, the mid-case (21) can include a bypass section (213).

[0013] The bypass section (213) is designed to divert the first gas flowing in through the first gas inlet (30) and direct it towards the cartridge (22) housed inside the mid-body (210). The bypass section (213) can be connected to communicate with the interior of the first cap (3) and the interior of the mid-body (210), respectively. In this case, the first cap (3) may include the first gas inlet (30). As a result, the bypass section (213) can communicate with the first gas inlet (30) through the interior of the first cap (3). Therefore, the first gas flowing in through the first gas inlet (30) can be diverted along the bypass section (213) and then flow into the cartridge (22) housed inside the mid-body (210). In this way, by using the bypass section (213) to divert the first gas, the fuel cell humidifier (1) according to the present invention can reduce the pressure of the first gas flowing into the cartridge (22) side. As a result, the fuel cell humidifier (1) according to the present invention can reduce the risk of the hollow fiber membrane (221) being damaged or broken due to the pressure of the first gas flowing into the mid-body (210). Therefore, the fuel cell humidifier (1) according to the present invention can reduce maintenance costs, operating costs, etc., by extending the service life of the hollow fiber membrane (221). Furthermore, the fuel cell humidifier (1) according to the present invention can contribute to increasing the operating rate of the fuel cell stack by extending the maintenance cycle for the hollow fiber membrane (221). The bypass portion (213) can protrude from the mid-body (210). This allows the fuel cell humidifier (1) according to the present invention to implement a flow path for bypassing the first gas to the outside of the mid-body (210) using the bypass portion (213). Accordingly, the fuel cell humidifier (1) according to the present invention can implement the flow path for bypassing the first gas and the flow path for the first gas flowing between the inside of the mid-body (210) and the outside of the cartridge (22) so as not to interfere with each other, using the bypass portion (213). As a result, the fuel cell humidifier (1) according to the present invention is implemented so that the flow path for bypassing the first gas does not narrow the flow path for the first gas flowing between the inside of the mid-body (210) and the outside of the cartridge (22). Accordingly, the fuel cell humidifier (1) according to the present invention can reduce the pressure of the first gas applied to the hollow fiber membrane (221) and at the same time enable smooth moisture exchange between the first gas and the second gas. The bypass portion (213) can be positioned so as to overlap the cartridge (22) housed inside the mid-body (210). One end of the bypass portion (213) can be connected to communicate with the inside of the first cap (3) located on the one end side of the mid-body (210). The other end of the bypass portion (213) can be connected to communicate with the inside of the mid-body (210). In this case, the other end of the bypass portion (213) can be positioned so as to overlap the cartridge (22) housed inside the mid-body (210). As a result, one end of the bypass portion (213) and the other end of the bypass portion (213) are positioned apart from each other, so that the fuel cell humidifier (1) according to the present invention can be realized such that the pressure gradually decreases as the first gas flows from one end of the bypass portion (213) to the other end of the bypass portion (213). In this case, as the flow velocity of the first gas gradually decreases, the pressure applied to the hollow fiber membrane (221) by the first gas can be reduced. Therefore, the fuel cell humidifier (1) according to the present invention can be implemented so that the first gas flows smoothly to the cartridge (22) side through the bypass section (213) by preventing abrupt changes in the pressure of the first gas. One end of the bypass section (213) and the other end of the bypass section (213) can be positioned at a distance from each other with respect to the first axial direction (X-axis direction).

[0014] The detour section (213) may include a first detour passage (213a) and a second detour passage (213b). The first bypass passage (213a) communicates with the interior of the first cap (3). The first bypass passage (213a) can function as an inlet for the first gas to flow into the bypass section (213). The first bypass passage (213a) can be formed by penetrating one end of the bypass section (213). The second bypass passage (213b) communicates with the interior of the mid-body (210). The second bypass passage (213b) can function as an outlet for the first gas to flow out from the bypass section (213). The second bypass passage (213b) can be formed by penetrating the other end of the bypass section (213). The second bypass passage (213b) and the first bypass passage (213a) can be formed by penetrating the bypass section (213) at different positions and in different directions. For example, with reference to Figure 9, the second bypass passage (213b) can be formed by penetrating the bypass section (213) from the other end of the bypass section (213) in a downward direction toward the mid body (210). In this case, the first bypass passage (213a) can be formed by penetrating the bypass section (213) from one end of the bypass section (213) in a leftward direction toward the first cap (3). As a result, the first gas can flow into the mid body (210) by flowing in through the first bypass passage (213a), flowing along the first axial direction (X-axis direction), and then flowing out downward through the second bypass passage (213b). Accordingly, the fuel cell humidifier (1) according to the present invention can further reduce the pressure of the first gas applied to the hollow fiber membrane (221) by being implemented such that the flow direction is changed during the process of flowing from the bypass section (213) into the interior of the mid-body (210). On the other hand, the second bypass passage (213b) can also be formed to penetrate the other end of the bypass section (213) and the entire mid-body (210). This allows the interior of the bypass section (213) and the interior of the mid-body (210) to be connected and communicate with each other through the second bypass passage (213b). The bypass section (213) and the mid-body (210) can also be formed integrally. The mid-case (21) may include a first mid-passage (210a). The first mid passage (210a) communicates with the interior of the first cap (3). The first mid passage (210a) can function as a passage for the second gas to flow in or out between the interior of the first cap (3) and the hollow fiber membrane (221). The first mid passage (210a) can be formed by penetrating one end of the mid body (210). The first mid passage (210a) can correspond to one end of the containment hole (211). One end of the hollow fiber membrane (221), which is fixed by the first fixed layer (223), can be placed in the first mid passage (210a).

[0015] The aforementioned mid-case (21) may include a second mid-passage (not shown). The second mid passage can function as a passage for the second gas to flow in or out between the inside of the second cap (4) and the hollow fiber membrane (221). The second mid passage can be formed by penetrating the other end of the mid body (210). The second mid passage can correspond to the other end of the receiving hole (211). The other end of the hollow fiber membrane (221), which is fixed by the second fixed layer (224), can be placed in the second mid passage. Here, the first mid passage (210a) and the first bypass passage (213a) can be implemented to have the following cross-sectional areas. In this case, the cross-sectional area is related to the area through which the fluid can pass through the first mid passage (210a) and the first bypass passage (213a). The cross-sectional areas of the first mid passage (210a) and the first bypass passage (213a) are the area of ​​the cross-section with respect to the vertical direction (Z-axis direction). The vertical direction (Z-axis direction) can be an axis perpendicular to the first axis direction (X-axis direction) and the second axis direction (Y-axis direction), respectively. The vertical direction (Z-axis direction) can also be an axis parallel to the second axis direction (Y-axis direction). In this case, the cartridge (22) can be arranged such that the second gas inlet (225) and the second gas outlet (226) face directions other than the direction facing the second bypass passage (213b). The first mid-passage (210a) and the first bypass passage (213a) can be arranged to be spaced apart from each other along the vertical direction (Z-axis direction). First, the cross-sectional area of ​​the first mid passage (210a) can be made larger than the cross-sectional area of ​​the first bypass passage (213a). In Comparative Example 1, where the cross-sectional area of ​​the first bypass passage (213a) is larger than or the same as the cross-sectional area of ​​the first mid passage (210a), the flow velocity of the first gas becomes too slow as it flows into the bypass section (213) through the first bypass passage (213a). As a result, in Comparative Example 1, the first gas cannot be transmitted to the hollow fiber membranes (221) located relatively further inside the hollow fiber membranes (221) inside the cartridge (22), which may reduce the humidification efficiency. To prevent this, the fuel cell humidifier (1) according to the present invention can make the cross-sectional area of ​​the first bypass passage (213a) smaller than the cross-sectional area of ​​the first mid passage (210a). As a result, the fuel cell humidifier (1) according to the present invention can increase the flow velocity of the first gas that flows into the bypass section (213) through the first bypass passage (213a) compared to Comparative Example 1, and can further increase the proportion of hollow fiber membranes (221) involved in humidification within the hollow fiber membranes (221) inside the cartridge (22). Therefore, the fuel cell humidifier (1) according to the present invention can have improved humidification efficiency compared to Comparative Example 1. Next, assuming the cross-sectional area of ​​the first mid-passage (210a) is 1, the cross-sectional area of ​​the first bypass passage (213a) can be set to 0.1 or more and 0.45 or less. That is, the cross-sectional area of ​​the first bypass passage (213a) may be 10% or more and 45% or less of the cross-sectional area of ​​the first mid-passage (210a). This allows the fuel cell humidifier (1) according to the present invention to be set to have a humidification efficiency and shell differential pressure within a predetermined range. The shell differential pressure relates to the pressure acting inside the mid-case (21) and the cartridge (22) during the process in which the first gas flows in through the first gas inlet (30) and flows out through the first gas outlet (212). If the shell differential pressure is too high, there is a risk that the mid-case (21), the cartridge (22), and the hollow fiber membrane (221) may be damaged or broken. If the shell differential pressure is too low, the time the first gas remains inside the mid-case (21) and the cartridge (22) may become too short, potentially reducing the humidification efficiency.

[0016] Referring to Figures 2 to 11, it can be confirmed through the experimental results in Figure 11 that when the cross-sectional area of ​​the first bypass passage (213a) is 10% to 45% of the cross-sectional area of ​​the first mid passage (210a), the humidification efficiency and shell differential pressure are realized to be within a predetermined range. Figure 11 shows the experimental results in which the humidification efficiency and shell differential pressure were measured by changing only the cross-sectional area of ​​the first bypass passage (213a) while keeping the cross-sectional areas of the first mid passage (210a) and the second bypass passage (213b) fixed. All experimental results in Figure 11 show the humidification efficiency and shell differential pressure measured when the same flow rate of the first gas was supplied through the first gas inlet (30) with the cross-sectional area of ​​the second bypass passage (213a) being 60% of the cross-sectional area of ​​the first mid passage (210a). Furthermore, in Figure 11, the cross-sectional area ratio refers to the ratio of the cross-sectional area of ​​the first bypass passage (213a) to the cross-sectional area of ​​the first mid passage (210a). As can be seen in Figure 11, Example 1 is implemented with the cross-sectional area of ​​the first bypass passage (213a) being 10% of the cross-sectional area of ​​the first mid passage (210a), exhibiting a humidification efficiency of 32 RH% and a shell differential pressure of 21 kPa. Example 2 is implemented with the cross-sectional area of ​​the first bypass passage (213a) being 30% of the cross-sectional area of ​​the first mid passage (210a), exhibiting a humidification efficiency of 30 RH% and a shell differential pressure of 19 kPa. Example 3 is implemented with the cross-sectional area of ​​the first bypass passage (213a) being 10% of the cross-sectional area of ​​the first mid passage (210a), exhibiting a humidification efficiency of 32 RH% and a shell differential pressure of 21 kPa. Thus, in Examples 1 to 3, it can be seen that by having the cross-sectional area of ​​the first bypass passage (213a) be 10% to 45% of the cross-sectional area of ​​the first mid passage (210a), the humidification efficiency is 30 to 32 RH% and the shell differential pressure is 18 to 21 kPa. In contrast to Examples 1 to 3, Comparative Example 2 is an example in which the cross-sectional area of ​​the first bypass passage (213a) is 8% of the cross-sectional area of ​​the first mid passage (210a), resulting in a humidification efficiency of 31.5 RH%, but a significantly higher shell differential pressure of 32 kPa. Through Comparative Example 2, it can be seen that when the cross-sectional area of ​​the first bypass passage (213a) is less than 10% of the cross-sectional area of ​​the first mid passage (210a), the shell differential pressure becomes significantly higher, increasing the risk of damage to the mid-case (21), the cartridge (22), and the hollow fiber membrane (221). Furthermore, in comparison with Examples 1 to 3, Comparative Example 3 is a case in which the cross-sectional area of ​​the first bypass passage (213a) is 47% of the cross-sectional area of ​​the first mid passage (210a), resulting in a shell differential pressure of 17.5 kPa, but the humidification efficiency is significantly lower at 22 RH%. Through Comparative Example 3, it can be seen that when the cross-sectional area of ​​the first bypass passage (213a) is more than 45% of the cross-sectional area of ​​the first mid passage (210a), the humidification efficiency becomes significantly lower.

[0017] Thus, the fuel cell humidifier (1) according to the present invention is realized to have a humidification efficiency of 30-32 RH% and a shell differential pressure of 18-21 kPa by having the cross-sectional area of ​​the first bypass passage (213a) be 10% or more and 45% or less of the cross-sectional area of ​​the first mid passage (210a). Therefore, the fuel cell humidifier (1) according to the present invention can reduce the risk of damage or breakage to the mid-case, the cartridge (22), and the hollow fiber membrane (221), and at the same time contribute to further improving the performance of the fuel cell system through improved humidification efficiency. On the other hand, the cross-sectional area of ​​the second bypass passage (213b) can be larger than the cross-sectional area of ​​the first bypass passage (213a). In this case, the cross-sectional area of ​​the second bypass passage (213b) is the area of ​​the cross-section with respect to the first axial direction (X-axis direction). In Comparative Example 4, where the cross-sectional area of ​​the second bypass passage (213b) is smaller than the cross-sectional area of ​​the first bypass passage (213a) or is the same size as the cross-sectional area of ​​the first bypass passage (213a), the flow velocity of the first gas becomes too fast as it flows into the interior of the mid-body (210) through the second bypass passage (213b). As a result, in Comparative Example 4, the pressure of the first gas applied to the hollow fiber membrane (221) increases excessively, and there is a higher risk that the hollow fiber membrane (221) may be damaged or broken. To prevent this, the fuel cell humidifier (1) according to the present invention can be configured such that the cross-sectional area of ​​the second bypass passage (213b) is larger than that of the first bypass passage (213a). As a result, the fuel cell humidifier (1) according to the present invention can reduce the flow velocity of the first gas that flows into the interior of the mid-body (210) through the second bypass passage (213b) compared to Comparative Example 4, thereby reducing the risk of the hollow fiber membrane (221) being damaged or broken by the pressure of the first gas. On the other hand, if the cross-sectional area of ​​the first mid passage (210a) is 1, the cross-sectional area of ​​the second bypass passage (213b) can be 0.2 or more and 0.8 or less. That is, the cross-sectional area of ​​the second bypass passage (213b) may be 20% or more and 80% or less of the cross-sectional area of ​​the first mid passage (210a). This allows the fuel cell humidifier (1) according to the present invention to be embodied so as to have a humidification efficiency and shell differential pressure within a predetermined range. In Comparative Example 5, in which the cross-sectional area of ​​the second bypass passage (213b) is embodied as less than 20% of the cross-sectional area of ​​the first mid passage (210a), the flow velocity of the first gas flowing into the mid body (210) through the second bypass passage (213b) becomes too fast, which may increase the risk of damage or breakage of the hollow fiber membrane (221). In Comparative Example 6, where the cross-sectional area of ​​the second bypass passage (213b) is greater than 80% of the cross-sectional area of ​​the first mid passage (210a), the flow velocity of the first gas flowing into the mid body (210) through the second bypass passage (213b) becomes too slow. As a result, the first gas cannot be transmitted to the hollow fiber membranes (221) that are relatively located on the inside, which may reduce the humidification efficiency. Taking this into consideration, by ensuring that the cross-sectional area of ​​the second bypass passage (213b) is between 20% and 80% of the cross-sectional area of ​​the first mid passage (210a), the fuel cell humidifier (1) according to the present invention can reduce the risk of damage or breakage of the hollow fiber membranes (221) and at the same time contribute to further improving the performance of the fuel cell system through improved humidification efficiency. Even when the cross-sectional area of ​​the second bypass passage (213b) is 20% or more and 80% or less of the cross-sectional area of ​​the first mid passage (210a), the cross-sectional area of ​​the second bypass passage (213b) can be made larger than the cross-sectional area of ​​the first bypass passage (213a).

[0018] Referring to Figures 2 to 10, the first cap (3) can include the first gas inlet (30), the first communication channel (32), the second communication channel (33), and the compartment (34). The first gas inlet (30) is through which the first gas is supplied to the interior of the mid-case (21). The first gas inlet (30) can be coupled to the first cap (3) so as to communicate with the interior of the first cap (3). Compared to a comparative example in which the first gas inlet (30) is located in the mid-case (21), the embodiment in which the first gas inlet (30) is located in the first cap (3) can reduce the distance between the first gas inlet (30) and the first gas supply source (not shown). As a result, the embodiment in which the first gas inlet (30) is located in the first cap (3) can shorten the length of the hose connecting the first gas inlet (30) and the supply source, and thus contribute to the overall miniaturization of the fuel cell system. Furthermore, in the embodiment in which the first gas inlet (30) is located on the first cap (3), it is possible to realize a straight hose for connecting the first gas inlet (30) and the supply source, thus contributing to a smaller fuel cell system. The supply source may be the fuel cell stack. In this case, the first gas may be exhaust gas discharged from the fuel cell stack. The first gas inlet (30) can protrude from the first cap (3). The first gas inlet (30) and the first port (31) can protrude in the same direction from each other. Using Figure 10 as a reference, the first gas inlet (30) and the first port (31) can protrude upward from the upper surface of the first cap (3). If the first gas is exhaust gas discharged from the fuel cell stack and the second gas is humidified gas supplied to the fuel cell stack, then both the first gas inlet (30) and the first port (31) can be connected to the fuel cell stack. In this case, the first port (31) can supply the second gas, humidified by the first gas, to the fuel cell stack. Therefore, the fuel cell humidifier (1) according to the present invention can improve the ease of connecting the first gas inlet (30) and the first port (31) to the fuel cell stack. Furthermore, the fuel cell humidifier (1) according to the present invention can contribute to miniaturizing the fuel cell system by shortening the length of the hose connecting the first gas inlet (30) and the first port (31) to the fuel cell stack. On the other hand, the first gas outlet (212) can protrude from the mid-body (210). The first gas outlet (212) and the first gas inlet (30) can protrude in the same direction from each other. The first gas outlet (212) and the first gas inlet (30) can also protrude in different directions from each other.

[0019] The first communication channel (32) connects the first gas inlet (30) and the bypass section (213). The first communication channel (32) can be located inside the first cap (3). The first communication channel (32) can be formed by penetrating one end of the first cap (3). One end of the first cap (3) is the portion facing one end of the mid-case (21). When the first cap (3) is coupled to the mid-case (21), the first communication channel (32) can be connected to the first bypass passage (213a). As a result, the first gas can flow into the first communication channel (32) through the first gas inlet (30) and then into the interior of the bypass section (213) through the first bypass passage (213a). Subsequently, the first gas can flow along the inside of the bypass section (213) and then flow into the inside of the mid-body (210) through the second bypass passage (213b). The second communication channel (33) connects the first port (31) and the hollow fiber membrane (221). The second communication channel (33) can be located inside the first cap (3). The second communication channel (33) can be formed by penetrating one end of the first cap (3). When the first cap (3) is coupled to the mid-case (21), the second communication channel (33) can be connected to the first mid-passage (210a). This allows the second gas to flow in or out between the inside of the first cap (3) and the hollow fiber membrane (221) through the second communication channel (33) and the first mid-passage (210a). The partition (34) spatially separates the first communication channel (32) and the second communication channel (33). The partition (34) is located inside the first cap (3) and can partition the first communication channel (32) and the second communication channel (33). As a result, the partition (34) can prevent the first gas and the second gas from mixing with each other inside the first cap (3). Referring to Figure 10, the first communication channel (32) is located above the partition (34) and the second communication channel (33) is located below the partition (34), so that the first communication channel (32) and the second communication channel (33) can be spatially separated by the partition (34). In this case, by arranging the first port (31) so as to cross the first communication channel (32) and the partitioned section (34), the first port (31) can be connected to communicate with the second communication channel (33). The present invention described above is not limited to the embodiments and accompanying drawings, and it will be apparent to those with ordinary skill in the art to which the present invention pertains that various substitutions, modifications, and alterations are possible without departing from the technical spirit of the present invention.

Claims

1. A mid-case provided in a fuel cell humidifier, which includes a humidification module for humidifying dry gas supplied to a fuel cell stack using a 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. A mid-body housing at least one cartridge containing multiple hollow fiber membranes; and The first gas, which flows in through the first gas inlet of the first cap, is diverted to a bypass section that directs it towards the cartridge housed inside the mid-body, The bypass portion protrudes from the mid-body at a position that overlaps with the cartridge housed inside the mid-body, The cross-sectional area of ​​the first mid passage formed through one end of the mid body is greater than the cross-sectional area of ​​the first bypass passage formed through one end of the bypass portion. The cross-sectional area of ​​the first bypass passage is characterized in that, if the cross-sectional area of ​​the first mid-passage is 1, then the cross-sectional area of ​​the first bypass passage is 0.1 or more and 0.45 or less. Mid-case for fuel cell humidifier.

2. A second bypass passage is formed in the bypass section, which communicates with the inside of the mid-body. The mid-case of a fuel cell humidifier according to claim 1, characterized in that the cross-sectional area of ​​the second bypass passage is larger than the cross-sectional area of ​​the first bypass passage.

3. A second bypass passage is formed in the bypass section, which communicates with the inside of the mid-body. The mid-case for a fuel cell humidifier according to claim 1, characterized in that, if the cross-sectional area of ​​the first mid-passage is 1, the cross-sectional area of ​​the second bypass passage is 0.2 or more and 0.8 or less.

4. A humidification module that uses a humidified gas to humidify the dry gas supplied to the fuel cell stack; A first cap coupled to one end of the humidifying module; and A second cap coupled to the other end of the humidification module; The humidification module includes a mid-case with both ends open, and at least one cartridge containing a plurality of hollow fiber membranes. The first cap includes a first gas inlet through which a first gas is supplied to the interior of the mid-case, and a first port communicating with the hollow fiber membrane through which a second gas is supplied or discharged. The mid-case includes a mid-body in which the cartridge is housed, and a bypass section that diverts the first gas that has flowed in through the first gas inlet and directs it towards the cartridge housed inside the mid-body. The bypass portion protrudes from the mid-body at a position that overlaps with the cartridge housed inside the mid-body, The first cap includes a first communication channel that connects the first gas inlet to the bypass section, and a second communication channel that connects the first port to the hollow fiber membrane. A first bypass passage communicating with the first communication channel is formed at one end of the bypass section. A first mid passage communicating with a second communication channel is formed at one end of the mid body. The cross-sectional area of ​​the first mid-passage is larger than the cross-sectional area of ​​the first bypass passage. The cross-sectional area of ​​the first bypass passage is characterized in that, if the cross-sectional area of ​​the first mid-passage is 1, then the cross-sectional area of ​​the first bypass passage is 0.1 or more and 0.45 or less. Humidifier for fuel cells.

5. The first cap is The fuel cell humidifier according to claim 4, characterized in that it includes a partition that spatially separates the first communication channel and the second communication channel.

6. The bypass section includes a second bypass passage that communicates with the interior of the mid-body, The fuel cell humidifier according to claim 5, characterized in that the first bypass passage and the second bypass passage are formed to penetrate the bypass portion at different positions and in different directions.

7. A second bypass passage is formed in the bypass section, which communicates with the inside of the mid-body. The fuel cell humidifier according to claim 4, characterized in that the cross-sectional area of ​​the second bypass passage is larger than the cross-sectional area of ​​the first bypass passage.

8. A second bypass passage is formed in the bypass section, which communicates with the inside of the mid-body. The fuel cell humidifier according to claim 4, characterized in that, if the cross-sectional area of ​​the first mid passage is 1, the cross-sectional area of ​​the second bypass passage is 0.2 or more and 0.8 or less.

9. The mid-case includes a first gas outlet for releasing the first gas discharged from the cartridge to the outside of the mid-case, The fuel cell humidifier according to claim 4, characterized in that the second cap includes a second port communicating with the hollow fiber membrane.

10. The aforementioned cartridge is The inner case containing the aforementioned hollow fiber membrane; A second gas inlet for introducing the first gas into the interior of the inner case; and The fuel cell humidifier according to claim 9, characterized in that it includes a second gas outlet for discharging the first gas from inside the inner case at a position separated from the second gas inlet.

11. The fuel cell humidifier according to claim 4, characterized in that the first gas inlet and the first port protrude in the same direction from each other.

Images