Fuel cell membrane humidifier and fuel cell system including the same

Abstract

The present invention relates to a fuel cell membrane humidifier that can adjust the pressure of dry gas in the fuel cell membrane humidifier by discharging dry gas to the outside depending on the pressure of dry gas in the membrane humidifier, and a fuel cell system including the same. The fuel cell membrane humidifier of an embodiment of the present invention includes a mid-case, a cap that is fastened to the mid-case and has a dry gas discharge hole through which dry gas is discharged, and a pressure adjustment unit that is formed in the cap and opens at least a portion of the dry gas discharge hole depending on the pressure of the dry gas in the cap, thereby adjusting the pressure of the dry gas in the cap.

Description

Technical Field

[0001] The present invention relates to a fuel cell membrane humidifier capable of discharging dry gas to the outside by the pressure of dry gas in the membrane humidifier and adjusting the pressure of dry gas in the fuel cell membrane humidifier, and a fuel cell system including the same.

Background Art

[0002] A fuel cell is a power generation type battery that combines hydrogen and oxygen to produce electricity. Different from general chemical batteries such as dry batteries and storage batteries, a fuel cell can continuously produce electricity as long as hydrogen and oxygen are supplied, and has the advantage that its efficiency is about twice as high as that of an internal combustion engine because there is no heat loss.

[0003] In addition, since the chemical energy generated by the combination of hydrogen and oxygen is directly converted into electrical energy, there is little emission of pollutants. Therefore, fuel cells not only are environmentally friendly but also have the advantage of being able to reduce concerns about resource depletion due to increased energy consumption.

[0004] 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), and alkaline fuel cells (AFCs) according to the type of electrolyte used.

[0005] Each of these fuel cells operates on basically the same principle, but differs from each other in terms of the type of fuel used, operating temperature, catalyst, electrolyte, etc. Among these, the polymer electrolyte fuel cell (PEMFC) is known to be the most promising not only for small-scale stationary power generation equipment but also for transportation systems because it operates at a low temperature compared to other fuel cells and has a high output density, enabling miniaturization.

[0006] One of the most important factors in improving the performance of a polymer electrolyte fuel cell (PEMFC) is to maintain the water content by supplying a certain amount of water or more to the polymer electrolyte membrane (Polymer Electrolyte Membrane or Proton Exchange Membrane: PEM) of the membrane-electrode assembly (MEA). This is because the power generation efficiency drops sharply when the polymer electrolyte membrane dries out.

[0007] Methods for humidifying the polymer electrolyte membrane include: 1) the bubbler humidification method in which water is filled in a pressure-resistant container and then the target gas is passed through a diffuser to supply moisture; 2) the direct injection method in which the amount of supply moisture required for the reaction of the fuel cell is calculated and moisture is directly supplied to the gas flow pipe through a solenoid valve; and 3) the humidification membrane method in which moisture is supplied to the gas flow layer using a polymer separation membrane.

[0008] Among these, the membrane humidification method of humidifying the polymer electrolyte membrane by providing water vapor to the gas supplied to the polymer electrolyte membrane using a membrane that selectively permeates only the water vapor contained in the exhaust gas is advantageous in that the humidifier can be reduced in weight and size.

[0009] When forming a module, a selectively permeable membrane used for membrane humidification is preferably a hollow fiber membrane with a large permeation area per unit volume. That is, when manufacturing a humidifier using a hollow fiber membrane, high integration of the hollow fiber membrane with a large contact surface area is possible, humidification of the fuel cell can be sufficiently performed even with a small capacity, use of low-cost materials is possible, and moisture and heat contained in the off-gas discharged from the fuel cell at a high temperature can be recovered and reused through the humidifier.

[0010] FIG. 1 is a diagram showing a fuel cell membrane humidifier according to the prior art and a fuel cell system including the same.

[0011] As shown in FIG. 1, a prior art fuel cell system includes a blower B, a fuel cell membrane humidifier 10 (hereinafter referred to as "membrane humidifier"), a fuel cell stack S, and flow paths P1, P2, P3, P4 connecting them. P1 is a dry gas supply flow path that supplies the dry gas collected by the blower B to the membrane humidifier 10, and P2 is a humid gas supply flow path that supplies the gas humidified by the membrane humidifier 10 to the fuel cell stack S. P3 is an exhaust gas supply flow path that supplies the exhaust gas discharged from the fuel cell stack S to the membrane humidifier 10, and P4 is an exhaust gas discharge flow path that discharges the exhaust gas after moisture exchange to the outside.

[0012] The membrane humidifier 10 includes a humidification module 11 in which moisture exchange occurs between the dry gas supplied from the blower B and the exhaust gas (wet gas) discharged from the fuel cell stack S, and caps 12 and 13 coupled to both ends of the humidification module 11.

[0013] A dry gas inlet 12a is formed in the cap 12 on the blower B side to supply the dry gas supplied from the blower B to the humidification module 11, and a dry gas outlet 13a is formed in the cap 13 on the stack S side to supply the gas humidified by the humidification module 11 to the fuel cell stack S.

[0014] The humidification module 11 includes a mid-case 11a having an off-gas inlet 11aa and an off-gas outlet 11ab, and a number of hollow fiber membranes 11b within the mid-case 11a. Both ends of the bundle of hollow fiber membranes 11b are fixed to potting portions 11c. The potting portions 11c are generally formed by curing a liquid polymer such as liquid polyurethane resin through a casting method.

[0015] The dry gas supplied from the blower B flows along the hollow of the hollow fiber membrane 11b. The exhaust gas flowing into the mid-case 11a through the exhaust gas inlet 11aa contacts the outer surface of the hollow fiber membrane 11b and then is discharged from the mid-case 11a through the exhaust gas outlet 11ab. When the exhaust gas contacts the outer surface of the hollow fiber membrane 11b, the moisture contained in the exhaust gas permeates through the hollow fiber membrane 11b, thereby humidifying the dry gas flowing along the hollow of the hollow fiber membrane 11b.

[0016] On the other hand, when the membrane humidifier 10 is driven normally, the dry gas flowing into the dry gas inlet 12a is humidified while flowing along the hollow of the hollow fiber membrane 11b and is discharged to the fuel cell stack S through the dry gas outlet 13a.

[0017] However, when the membrane humidifier 10 cannot be driven normally for various reasons such as abnormal operation of the fuel cell stack S, damage to the hollow fiber membrane 11b, or blockage of the flow path of the hollow fiber membrane 11b, the dry gas flowing into the dry gas inlet 12a may not be discharged through the dry gas outlet 13a. As a result, the pressure of the dry gas rises within the membrane humidifier 10, and there is a risk of damage to the membrane humidifier 10.

Summary of the Invention

Problems to be Solved by the Invention

[0018] An object of the present invention is to provide a fuel cell membrane humidifier that can discharge a dry gas to the outside by the pressure of the dry gas in the membrane humidifier and adjust the pressure of the dry gas in the fuel cell membrane humidifier, and a fuel cell system including the same.

Means for Solving the Problems

[0019] The fuel cell membrane humidifier according to an embodiment of the present invention includes a mid-case, a cap fastened to the mid-case and having a dry gas discharge hole through which the dry gas is discharged, and a pressure adjusting portion formed in the cap to open at least a part of the dry gas discharge hole by the pressure of the dry gas in the cap and adjust the pressure of the dry gas in the cap.

[0020] In the fuel cell membrane humidifier according to an embodiment of the present invention, the pressure adjusting portion includes a buffer housing communicating with the dry gas discharge hole, an opening and closing member that moves forward and backward in the buffer housing, an elastic member formed on the inner wall of the buffer housing and the opening and closing member, and that is compressed or extended by the pressure of the dry gas in the cap, and a gas discharge port for discharging the dry gas flowing into the buffer housing to the outside.

[0021] In the fuel cell membrane humidifier according to an embodiment of the present invention, a locking projection that is formed by extending from the cap and can be engaged with the opening and closing member may be formed at the opening of the buffer housing on the dry gas discharge hole side.

[0022] In the fuel cell membrane humidifier according to an embodiment of the present invention, a locking projection that protrudes from the buffer housing and can be engaged with the opening and closing member may be formed.

[0023] In the fuel cell membrane humidifier according to an embodiment of the present invention, the pressure regulating unit may include a buffer housing communicating with the dry gas discharge hole, an opening and closing member hinged to the upper end of the dry gas discharge hole and performing a turning motion, an elastic member formed behind the opening and closing member, and a gas discharge port for discharging the dry gas flowing into the buffer housing to the outside.

[0024] In the fuel cell membrane humidifier according to an embodiment of the present invention, the pressure regulating unit may include a buffer housing communicating with the dry gas discharge hole, an opening and closing member hinged to the lower end of the dry gas discharge hole and performing a turning motion, an elastic member formed in front of the opening and closing member, and a gas discharge port for discharging the dry gas flowing into the buffer housing to the outside.

[0025] In the fuel cell membrane humidifier according to an embodiment of the present invention, the pressure regulating unit may include a heat expansion metal formed on the inner wall of the cap and expanding due to a temperature change of the dry gas in the cap, and a through hole formed in the heat expansion metal and opening at least a part of the dry gas discharge hole due to the expansion of the heat expansion metal.

[0026] In the fuel cell membrane humidifier according to an embodiment of the present invention, the pressure regulating unit may further include a stopper formed at an end of the heat expansion metal and made of a heat resistant material.

[0027] A fuel cell system according to an embodiment of the present invention includes a blower for supplying dry gas, a fuel cell stack, a mid-case, a cap fastened to the mid-case and having a dry gas discharge hole through which dry gas is discharged, and a fuel cell membrane humidifier formed in the cap and including a pressure regulating unit that opens at least a part of the dry gas discharge hole by the pressure of the dry gas in the cap and regulates the pressure of the dry gas in the cap.

[0028] In the fuel cell system according to an embodiment of the present invention, the pressure regulating unit may include a buffer housing communicating with the dry gas discharge hole, an opening and closing member that moves back and forth within the buffer housing, an elastic member formed on the inner wall of the buffer housing and the opening and closing member, and compressed or extended by the pressure of the dry gas in the cap, and a gas discharge port that discharges the dry gas flowing into the buffer housing to the outside.

[0029] In the fuel cell system according to an embodiment of the present invention, a locking projection that is formed by extending from the cap and can be hooked by the opening and closing member may be formed at the opening on the dry gas discharge hole side of the buffer housing.

[0030] In the fuel cell system according to an embodiment of the present invention, a locking projection that protrudes from the buffer housing and can be hooked by the opening and closing member may be formed.

[0031] In the fuel cell system according to an embodiment of the present invention, the pressure regulating unit may include a buffer housing communicating with the dry gas discharge hole, an opening and closing member that is hinge-connected to the upper end of the dry gas discharge hole and swings, an elastic member formed behind the opening and closing member, and a gas discharge port that discharges the dry gas flowing into the buffer housing to the outside.

[0032] In the fuel cell system according to an embodiment of the present invention, the pressure regulating unit may include a buffer housing communicating with the dry gas discharge hole, an opening and closing member that is hinge-connected to the lower end of the dry gas discharge hole and swings, an elastic member formed in front of the opening and closing member, and a gas discharge port that discharges the dry gas flowing into the buffer housing to the outside.

[0033] In the fuel cell system according to an embodiment of the present invention, the pressure regulating unit may be formed on the inner wall of the cap and include a heat-expandable metal that expands due to a temperature change of the dry gas in the cap, and a through-hole formed in the heat-expandable metal and opening at least a part of the dry gas discharge hole due to the expansion of the heat-expandable metal.

[0034] In the fuel cell system according to an embodiment of the present invention, the pressure regulating unit may be formed at an end of the heat-expandable metal and further include a stopper made of a heat-resistant material.

[0035] Specific matters of implementation examples according to various other aspects of the present invention are included in the following detailed description.

Advantages of the Invention

[0036] According to the fuel cell membrane humidifier according to an embodiment of the present invention and the fuel cell system including the same, the dry gas can be discharged to the outside by the pressure of the dry gas flowing into the membrane humidifier, and the pressure of the dry gas in the membrane humidifier can be adjusted. Therefore, when the membrane humidifier cannot be driven normally for various reasons, damage to the membrane humidifier can be prevented by adjusting the pressure in the membrane humidifier.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0038] The present invention can be subjected to various transformations and can have various embodiments. Therefore, specific embodiments will be exemplified and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all transformations, equivalents, and alternatives included in the spirit and technical scope of the present invention.

[0039] The terms used in the present invention are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present invention, terms such as "including" or "having" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should not be construed as precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, with reference to the drawings, a fuel cell membrane humidifier according to an embodiment of the present invention and a fuel cell system including the same will be described.

[0040] FIGS. 2 to 5 are diagrams showing a fuel cell membrane humidifier according to an embodiment of the present invention and a fuel cell system including the same.

[0041] As shown in FIGS. 2 to 5, a fuel cell membrane humidifier according to an embodiment of the present invention and a fuel cell system including the same can include a blower B, a fuel cell membrane humidifier 100: 101 to 104 (hereinafter also referred to as "membrane humidifier"), a fuel cell stack S, and flow paths P10, P20, P30, P40 connecting them.

[0042] The blower B collects gas in the atmosphere and supplies it to the membrane humidifier 100: 101 to 104. The output size of the blower B can be determined according to the output size of the fuel cell stack S. Optionally, a filter (not shown) for removing particulate matter may be provided at the front end of the blower B, and a cooler (not shown) for cooling the dry gas supplied to the membrane humidifier 100 may be provided between the blower B and the membrane humidifier 100.

[0043] The membrane humidifier 100 humidifies the dry gas and supplies it to the fuel cell stack S. The membrane humidifier 100 includes a humidification module 110 that humidifies the dry gas supplied from the blower B with the moisture in the exhaust gas discharged from the fuel cell stack S. Each of both ends of the humidification module 110 is coupled to caps 120 and 130. The humidification module 110 and the caps 120 and 130 may be separately formed or integrally formed.

[0044] A dry gas inlet 121 is formed in the cap 120 on the blower B side, supplies the dry gas supplied from the blower B to the humidification module 110, a dry gas outlet 131 is formed in the cap 130 on the stack S side, and supplies the gas humidified by the humidification module 110 to the fuel cell stack S.

[0045] In the cap 120 on the blower B side, a pressure adjustment unit 200: 210 to 240 that is closed or opened by the pressure of the dry gas in the cap 120 and adjusts the pressure of the dry gas in the cap 120 is formed. The pressure adjustment unit 200: 210 to 240 will be described later with reference to FIGS. 6 to 13.

[0046] The dry gas inlet 121 is connected to a dry gas supply passage P10 that connects the blower B and the membrane humidifier 100, and the dry gas outlet 131 is connected to a humidified gas supply passage P20 that connects the cap 130 on the fuel cell stack S side and the fuel cell stack S. The exhaust gas discharged from the fuel cell stack S is supplied to the membrane humidifier 100 via the exhaust gas supply passage P30, and the exhaust gas that has undergone moisture exchange in the membrane humidifier 100 is discharged to the outside via the exhaust gas discharge passage P40.

[0047] As shown in FIGS. 2 and 3, the humidification module 110 is a device in which moisture exchange occurs between the dry gas supplied from the blower B and the exhaust gas, and includes a mid-case 111 having an exhaust gas inlet 111a and an exhaust gas outlet 111b, and a large number of hollow fiber membranes 112 housed in the mid-case 111. Both ends of the bundle of the hollow fiber membranes 112 are fixed to the potting part 113.

[0048] Alternatively, as shown in FIGS. 4 and 5, the humidification module 110 can include at least one cartridge 20 including a plurality of hollow fiber membranes 22 and a potting portion 23 for fixing them to each other. In this case, the hollow fiber membranes 22 and the potting portion 23 can be formed within an inner case 21 which is a separate cartridge case. In this case, the hollow fiber membranes 22 can be accommodated within the inner case 21, and the potting portion 23 can be formed at the end of the inner case 21. When the humidification module 110 includes the cartridge 20, a fixing layer 115 for fixing the cartridge can be formed between both end portions of the cartridge and the mid-case 111. The fixing layer 115 can be a resin layer formed of resin, or a gasket assembly that is hermetically coupled through mechanical assembly. The inner case 21 includes mesh holes 24 arranged in a mesh pattern for fluid communication with the first space S1 and the second space S2.

[0049] As shown in FIGS. 2 and 4, the internal space of the mid-case 111 can be partitioned into a first space S1 and a second space S2 by a partition wall 114. The partition wall 114 can prevent the exhaust gas flowing into the exhaust gas inlet 111a from bypassing directly to the exhaust gas outlet 111b without exchanging moisture with the hollow fiber membranes 112 and 22.

[0050] Alternatively, as shown in FIGS. 3 and 5, the internal space of the mid-case 111 can be partitioned into a first space S1 and a second space S2 by a central recessed portion 116 recessed in the central portion of the mid-case 111. The central recessed portion 116 can prevent the exhaust gas flowing into the exhaust gas inlet 111a from bypassing directly to the exhaust gas outlet 111b without exchanging moisture with the hollow fiber membranes 112 and 22.

[0051] The mid-case 111 and the caps 120, 130 can each be independently formed of a rigid plastic or metal, and can have a circular or polygonal cross-section in the width direction. The circular shape includes an elliptical shape, and the polygonal shape includes a polygon with rounded corners. For example, the rigid plastic can be polycarbonate, polyamide (PA), polyphthalamide (PPA), polypropylene (PP), or the like.

[0052] The hollow fiber membranes 112, 22 can include a polymer membrane formed of a polysulfone resin, a polyethersulfone resin, a sulfonated polysulfone resin, a polyvinylidene fluoride (PVDF) resin, a polyacrylonitrile (PAN) resin, a polyimide resin, a polyamideimide resin, a polyesterimide resin, or a mixture of at least two or more of these. The potting part 113 can be formed by curing a liquid resin such as a liquid polyurethane resin through a casting method such as deep potting or centrifugal potting.

[0053] In the embodiment of the present invention exemplarily shown in FIGS. 2 to 5, in the cap 120 on the blower B side, a pressure regulating part 200: 210 to 240 that is closed or opened by the pressure of the dry gas in the cap 120 and regulates the pressure of the dry gas in the cap 120 is formed. This will be described with reference to FIGS. 6 to 13.

[0054] FIG. 6 is a diagram showing the pressure regulating part according to the first embodiment, and FIG. 7 is a diagram showing the operation process of the pressure regulating part according to the first embodiment.

[0055] As shown in FIG. 6, the pressure regulating part 210 of the first embodiment can include a buffer housing 211, an opening / closing member 212, an elastic member 213, and a gas discharge port 214.

[0056] The buffer housing 211 is formed in a predetermined shape so as to communicate with the dry gas discharge hole 122 formed in the cap 120. The buffer housing 211 provides a space in which the opening and closing member 212 can move back and forth, and when the opening and closing member 212 moves backward to open the dry gas discharge hole 122, it provides a space in which the dry gas in the cap 120 can flow.

[0057] At the opening on the dry gas discharge hole 122 side of the buffer housing 211, a locking projection 211a that extends from the cap 120 and can be engaged with the opening and closing member 212 may be formed. Alternatively, the locking projection 211a may be formed to protrude from at least one of the upper surface or the lower surface of the buffer housing 211.

[0058] The opening and closing member 212 has an area larger than the area of the dry gas discharge hole 122, can be engaged with the locking projection 211a, and is formed in a shape that can open and close the dry gas discharge hole 122.

[0059] The front surface of the opening and closing member 212 opens and closes the dry gas discharge hole 122, and an elastic member 213 that can be compressed or extended according to the magnitude of the pressure of the dry gas in the cap 120 is formed on the rear surface of the opening and closing member 212. The elastic member 213 can be fixedly formed on the rear surface of the opening and closing member 212 and one side inner wall of the buffer housing 211. The elastic member 213 can be, for example, a spring. Of course, it is not limited to this, and heat-resistant rubber, synthetic resin, etc. can be the material of the elastic member 213.

[0060] A gas discharge port 214 is formed on at least one surface of the buffer housing 211. As shown in FIG. 7, when the opening and closing member 212 moves backward to open the dry gas discharge hole 122, the dry gas in the cap 120 flows into the buffer housing 211 through the dry gas discharge hole 122 and is discharged to the outside through the gas discharge port 214 and the exhaust gas discharge passage P40 (see FIG. 2).

[0061] FIG. 8 is a diagram showing a pressure regulating unit according to the second embodiment, and FIG. 9 is a diagram showing an operating process of the pressure regulating unit according to the second embodiment.

[0062] As shown in FIG. 8, the pressure regulating unit 220 of the second embodiment may include a buffer housing 221, an opening / closing member 222, an elastic member 223, and a gas discharge port 224.

[0063] The buffer housing 221 is formed in a predetermined shape and communicates with the dry gas discharge hole 122 formed in the cap 120. The buffer housing 221 provides a space in which the hinge-connected opening / closing member 222 can pivot, and when the opening / closing member 222 pivots backward to open at least a part of the dry gas discharge hole 122, it provides a space through which the dry gas in the cap 120 can flow. Here, the inner side of the cap is referred to as "front" and the outer side of the cap is referred to as "rear".

[0064] The opening / closing member 222 is hinge-connected to the upper end of the dry gas discharge hole 122, and its end is formed in an arch shape so that it can pivot without friction under the pressure of the dry gas.

[0065] The front surface of the opening / closing member 222 opens and closes the dry gas discharge hole 122, and an elastic member 223 that can be compressed or extended according to the magnitude of the pressure of the dry gas in the cap 120 is formed on the rear surface of the opening / closing member 222. The elastic member 223 can be fixedly formed on the rear surface of the opening / closing member 222 and the upper inner wall of the buffer housing 221. The elastic member 223 can be, for example, a spring. Of course, it is not limited to this, and heat-resistant rubber, synthetic resin, etc. can be the material of the elastic member 223.

[0066] The gas discharge port 224 is formed on at least one surface of the buffer housing 221. As shown in FIG. 9, when the opening / closing member 222 pivots backward to open the dry gas discharge hole 122, the dry gas in the cap 120 flows into the buffer housing 221 through the dry gas discharge hole 122 and is discharged to the outside through the gas discharge port 224 and the exhaust gas discharge channel P40 (see FIG. 2).

[0067] FIG. 10 is a diagram showing a pressure regulating unit according to the third embodiment, and FIG. 11 is a diagram showing an operation process of the pressure regulating unit according to the third embodiment.

[0068] As shown in FIG. 10, the pressure regulating unit 230 of the third embodiment can include a buffer housing 231, an opening / closing member 232, an elastic member 233, and a gas discharge port 234. The pressure regulating unit 230 of the third embodiment is different from the pressure regulating unit 220 of the second embodiment described above only in the installation positions of the opening / closing member 232 and the elastic member 233, and the remaining configurations are substantially the same, so repeated description will be omitted.

[0069] In this embodiment, the opening / closing member 232 is hinge-connected to the lower end of the dry gas discharge hole 122, and its end is formed in an arch shape so that it can rotate without friction under the pressure of the dry gas.

[0070] The front surface of the opening / closing member 232 opens and closes the dry gas discharge hole 122, and an elastic member 233 that can be compressed or extended according to the magnitude of the pressure of the dry gas in the cap 120 is formed on the rear surface of the opening / closing member 232. The elastic member 233 can be fixedly formed on the front surface of the opening / closing member 232 and the inner wall of the dry gas discharge hole 122.

[0071] As shown in FIG. 11, when the opening / closing member 232 rotates backward to open the dry gas discharge hole 122, the dry gas in the cap 120 flows into the buffer housing 231 through the dry gas discharge hole 122 and is discharged to the outside through the gas discharge port 234 and the exhaust gas discharge flow path P40 (see FIG. 2).

[0072] FIG. 12 is a diagram showing a pressure regulating unit according to the fourth embodiment, and FIG. 13 is a diagram showing an operation process of the pressure regulating unit according to the fourth embodiment.

[0073] As shown in FIG. 12, the pressure regulating unit 240 of the fourth embodiment can include a bimetal 241, a through hole 242, a stopper 243, and a gas discharge port 244.

[0074] The thermal expansion metal 241 is formed in a substantially rod shape near the inner wall of the cap 120 and near the dry gas discharge hole 122. The thermal expansion metal 241 is made of a metal material that expands or contracts due to a change in the temperature of the dry gas.

[0075] A through hole 242 penetrating the thermal expansion metal 241 is formed at a predetermined position of the thermal expansion metal 241. The through hole 242 is formed in a shape corresponding to the shape of the dry gas discharge hole 122, and at least a part of the dry gas discharge hole 122 can be opened by the expansion of the thermal expansion metal 241, and the dry gas discharge hole 122 can be closed by the contraction of the thermal expansion metal 241.

[0076] A stopper 243 can be formed at the end of the thermal expansion metal 241. The stopper 243 is made of a heat-resistant material with less expansion / contraction due to a change in the temperature of the dry gas compared to the thermal expansion metal 241, and serves as a base point for the expansion / contraction of the thermal expansion metal 241.

[0077] The gas discharge port 244 is formed to communicate with the dry gas discharge hole 122.

[0078] When the membrane humidifier operates normally, the dry gas in the cap 120 will have a certain pressure and the temperature can also be maintained constant. (Ideal gas state equation) In this case, as shown in FIG. 12, the thermal expansion metal 241 will maintain a non-expanded state, and the through hole 242 will maintain a position closing the dry gas discharge hole 122.

[0079] When the membrane humidifier operates abnormally, the pressure of the dry gas in the cap 120 will increase, and accordingly the temperature will also increase. In this case, as shown in FIG. 13, the thermal expansion metal 241 will expand, and due to the expansion of the thermal expansion metal 241, the through hole 242 will move and be arranged at a position opening the dry gas discharge hole 122.

[0080] When the dry gas discharge hole 122 is opened, the dry gas in the cap 120 is discharged to the outside through the dry gas discharge hole 122, the gas discharge port 244, and the exhaust gas discharge flow path P40 (see FIG. 2).

[0081] After a certain period of time, when the dry gas is discharged and the pressure drops, the temperature also drops. The thermally expandable metal 241 contracts while the through-hole 242 returns to its original position, and as shown in Fig. 12, the through-hole 242 closes the dry gas discharge hole 122.

[0082] According to such a fuel cell membrane humidifier according to an embodiment of the present invention and a fuel cell system including the same, the pressure of the dry gas flowing into the membrane humidifier can be adjusted by discharging the dry gas to the outside according to the pressure of the dry gas.

[0083] Therefore, when the membrane humidifier cannot be driven normally for various reasons, damage to the membrane humidifier can be prevented by adjusting the pressure inside the membrane humidifier.

[0084] As described above, an embodiment of the present invention has been described. However, those having ordinary knowledge in the art can make various modifications and changes to the present invention by adding, changing, deleting, or adding components within the scope not deviating from the idea of the present invention described in the claims, and this can also be said to be included within the scope of the rights of the present invention.

Explanation of Reference Numerals

[0085] 100(101~104): Fuel cell membrane humidifier 110: Humidification module 111: Mid-case 112: Hollow fiber membrane 113: Potting part 114: Partition wall 116: Central recessed part 111a: Exhaust gas inlet 111b: Exhaust gas outlet 20: Cartridge 21: Inner case 22: Hollow fiber membrane 23: Potting part 24: Mesh hole part 120, 130: Cap 200(210~240): Pressure regulating part B: Blower S: Fuel cell stack P10: Dry gas supply flow path P20: Humidified gas supply flow path P30: Exhaust gas supply flow path P40: Exhaust gas discharge flow path

Claims

1. A mid-case, A cap fastened to the mid-case and having a dry gas discharge hole through which dry gas is discharged, A pressure regulating part formed in the cap, opening at least a part of the dry gas discharge hole by the pressure of the dry gas in the cap, and regulating the pressure of the dry gas in the cap, A fuel cell membrane humidifier comprising: The pressure regulating part is A heat expansion metal formed on the inner wall of the cap and expanding by a temperature change of the dry gas in the cap, A through-hole formed in the heat expansion metal and opening at least a part of the dry gas discharge hole by the expansion of the heat expansion metal, A fuel cell membrane humidifier.

2. The pressure regulating part A stopper formed at an end of the heat expansion metal and made of a heat-resistant material The fuel cell membrane humidifier according to claim 1, further comprising:

3. A blower for supplying dry gas, A fuel cell stack, A mid-case, a cap fastened to the mid-case and having a dry gas discharge hole through which dry gas is discharged, and a pressure regulating part formed in the cap, opening at least a part of the dry gas discharge hole by the pressure of the dry gas in the cap and regulating the pressure of the dry gas in the cap, a fuel cell membrane humidifier, A fuel cell system comprising: The pressure regulating part is A heat expansion metal formed on the inner wall of the cap and expanding by a temperature change of the dry gas in the cap, A through-hole formed in the heat expansion metal and opening at least a part of the dry gas discharge hole by the expansion of the heat expansion metal, A fuel cell system.

4. The pressure regulating unit is, A stopper formed at an end of the heat-expandable metal and made of a heat-resistant material The fuel cell system according to claim 3, further comprising the same.

5. A humidified gas supply passage for supplying the gas humidified by the fuel cell membrane humidifier to the fuel cell stack, An exhaust gas supply passage for supplying the exhaust gas discharged from the fuel cell stack to the fuel cell membrane humidifier, An exhaust gas discharge passage for discharging the exhaust gas moisture-exchanged by the fuel cell membrane humidifier to the outside, The fuel cell system according to claim 3 or 4, comprising the same.

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