FUEL CELL MEMBRANE HUMIDIFIER AND FUEL CELL SYSTEM COMPRISING SAME

Abstract

The present invention relates to a fuel cell membrane humidifier and a fuel cell system comprising same, wherein exhaust gas discharged from a fuel cell stack is introduced into a fuel cell membrane humidifier in both directions, whereby the humidification efficiency can be improved. The fuel cell system according to an embodiment of the present invention comprises: a blower which supplies dry gas; a fuel cell stack; and a fuel cell membrane humidifier which includes a mid-case, a first exhaust gas inlet formed at one surface of the mid-case, a second exhaust gas inlet formed at the other surface of the mid-case, and one exhaust gas outlet formed at the other surface of the mid-case.

Claims

1. A fuel cell membrane humidifier comprising: a mid-case; a first off-gas inlet formed on one side of one surface of the mid-case and a second off-gas inlet formed on the other side of the one surface of the mid-case; and an off-gas outlet formed on the other surface of the mid-case.

2. The fuel cell membrane humidifier of claim 1, wherein the first off-gas inlet and the second off-gas inlet are formed in a direction inclined at a preset angle.

3. The fuel cell membrane humidifier of claim 1, comprising partition walls configured to partition an inner space of the mid-case into a first space and a second space, wherein the first off-gas inlet is formed in the first space, and the second off-gas inlet is formed in the second space.

4. The fuel cell membrane humidifier of claim 3, wherein the off-gas outlet is formed between the first space and the second space.

5. The fuel cell membrane humidifier of claim 3, wherein the off-gas outlet is formed between the partition walls for partition into the first space and the second space.

6. A fuel cell system comprising: a blower configured to supply a dry gas; a fuel cell stack; and a fuel cell membrane humidifier including a mid-case, a first off-gas inlet formed on one side of one surface of the mid-case, a second off-gas inlet formed on the other side of the one surface of the mid-case, and an off-gas outlet formed on the other surface of the mid-case.

7. The fuel cell system of claim 6, wherein the first off-gas inlet and the second off-gas inlet are formed in a direction inclined at a preset angle.

8. The fuel cell system of claim 6, comprising partition walls configured to partition an inner space of the mid-case into a first space and a second space, wherein the first off-gas inlet is formed in the first space, and the second off-gas inlet is formed in the second space.

9. The fuel cell system of claim 8, wherein the off-gas outlet is formed between the first space and the second space.

10. The fuel cell system of claim 8, wherein the off-gas outlet is formed between the partition walls for partition into the first space and the second space.

11. The fuel cell system of claim 6, comprising: a humidified gas supply flow path configured to supply a gas humidified in the fuel cell membrane humidifier to the fuel cell stack; an off-gas supply flow path configured to supply the off-gas discharged from the fuel cell stack to the fuel cell membrane humidifier; and a first off-gas branch flow path branched from the off-gas supply flow path and connected to the first off-gas inlet, and a second off-gas branch flow path branched from the off-gas supply flow path and connected to the second off-gas inlet.

12. The fuel cell system of claim 11, comprising a flow adjustment means for adjusting a flow rate of the off-gas to the first off-gas branch flow path and the second off-gas branch flow path, the flow adjustment means being formed between the first off-gas branch flow path and the second off-gas branch flow path.

13. The fuel cell membrane humidifier of claim 1, wherein the humidification module comprise at least one cartridge including a plurality of hollow fiber membranes and a potting portions that fix the hollow fiber membranes to each other.

14. The fuel cell membrane humidifier of claim 13, wherein the hollow fiber membranes formed in an inner case, and the potting portions formed at ends of the inner case.

15. The fuel cell membrane humidifier of claim 14, further comprises a resin layer for fixing the cartridge formed between both ends of the cartridge and the mid-case.

16. The fuel cell membrane humidifier of claim 14, further comprises a gasket assembly for airtight coupling through a mechanical assembly.

17. The fuel cell system of claim 6, wherein the humidification module comprise at least one cartridge including a plurality of hollow fiber membranes and a potting portions that fix the hollow fiber membranes to each other.

18. The fuel cell system of claim 17, wherein the hollow fiber membranes formed in an inner case, and the potting portions formed at ends of the inner case.

19. The fuel cell system of claim 18, further comprises a resin layer for fixing the cartridge formed between both ends of the cartridge and the mid-case.

20. The fuel cell system of claim 18, further comprises a gasket assembly for airtight coupling through a mechanical assembly.

Description

DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a view illustrating a fuel cell membrane humidifier and a fuel cell system comprising the same according to the related art.

[0037] FIG. 2 is a view illustrating a fuel cell membrane humidifier and a fuel cell system comprising the same according to an embodiment of the present invention.

[0038] FIG. 3 is a view conceptually illustrating an off-gas flow in the fuel cell membrane humidifier according to the embodiment of the present invention.

[0039] FIG. 4 is a view illustrating a fuel cell membrane humidifier and a fuel cell system comprising the same according to another embodiment of the present invention.

[0040] FIG. 5 is a view conceptually illustrating an off-gas flow in the fuel cell membrane humidifier according to the other embodiment of the present invention.

MODE FOR DISCLOSURE

[0041] Since various changes may be made to the present invention, which may have several embodiments, specific embodiments will be illustrated and described in detail herein. However, it will be understood that this is not intended to limit the present invention to the specific embodiments, and all changes, equivalents, or substitutions included in the spirit and scope of the present invention are included.

[0042] specific embodiments only and are not intended to limit the present invention. The singular expressions “a,” “an” and “the” include the plural expressions, unless the context clearly indicates otherwise. It will be understood that the terms “include” or “have” herein specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described herein, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof. Hereinafter, a fuel cell system according to embodiments of the present invention will be described with reference to the drawings.

[0043] FIG. 2 is a view illustrating a fuel cell membrane humidifier and a fuel cell system comprising the same according to an embodiment of the present invention.

[0044] As illustrated in FIG. 2, the fuel cell membrane humidifier and the fuel cell system comprising the same according to the embodiment of the present invention include a blower B, a fuel cell membrane humidifier (100; hereinafter also referred to as a ‘membrane humidifier’), a fuel cell stack S, and flow paths P10, P20, P30, and P40 that connect these.

[0045] The blower B collects a gas in an atmosphere and supplies the gas to the membrane humidifier 100. An output magnitude of the blower B may be determined depending on an output magnitude of the fuel cell stack S. Optionally, a filter (not illustrated) that removes fine dust may be installed before the blower B, and a cooler (not illustrated) that cools a dry gas supplied to the membrane humidifier 100 may be installed between the blower B and the membrane humidifier 100.

[0046] The membrane humidifier 100 humidifies the dry gas and supplies the dry gas 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 moisture in an off-gas discharged from the fuel cell stack S. Both ends of the humidification module 110 are coupled to caps 120 and 130. The humidification module 110 and the caps 120 and 130 may be separately formed or may be integrally formed.

[0047] A dry gas inlet 121 is formed in the cap 120 on the blower B side to supply the dry gas supplied from the blower B to the humidification module 110, and a dry gas outlet 131 is formed in the cap 130 on the stack S side to supply air humidified by the humidification module 110 to the fuel cell stack S.

[0048] The dry gas inlet 121 is connected to a dry gas supply flow path P10 that connects the blower B to the membrane humidifier 100, and the dry gas outlet 131 is connected to a humidified gas supply flow path P20 that connects the cap 130 on the fuel cell stack S side to the fuel cell stack S.

[0049] The humidification module 110 is a device in which moisture exchange between the dry gas supplied from the blower B and the off-gas occurs, and includes a mid-case 111 having a pair of off-gas inlets 111a1 and 111a2 and an off-gas outlet 111b, and a plurality of hollow fiber membranes 112 accommodated in the mid-case 111. Both ends of a bundle of hollow fiber membranes 112 are fixed to potting portions 113.

[0050] Alternatively, the humidification module 110 may include at least one cartridge including the plurality of hollow fiber membranes 112 and the potting portions 113 that fix the hollow fiber membranes 112 to each other. In this case, the hollow fiber membranes 112 and the potting portions 113 may be formed in a separate cartridge case (an inner case). In this case, the hollow fiber membranes 112 may be accommodated in the inner case, and the potting portions 113 may be formed at ends of the inner case. When the humidification module 110 includes the cartridge, a resin layer for fixing the cartridge may be formed between both ends of the cartridge and the mid-case 111, or a gasket assembly for airtight coupling through a mechanical assembly may be further included.

[0051] The mid-case 111 and the caps 120 and 130 may be independently formed of hard plastic or metal, and may have a circular or polygonal cross section in a width direction. The “circular” include oval, and the “polygonal” includes polygonal with rounded corners. Examples of the hard plastic may include polycarbonate, polyamide (PA), polyphthalamide (PPA), and polypropylene (PP).

[0052] The hollow fiber membranes 112 may 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 two or more of these, and the potting portions 113 may be formed by curing a liquid resin such as a liquid polyurethane resin through a casting scheme such as deep potting or centrifugal potting.

[0053] In the embodiment of the present invention, the off-gas inlets 111a1 and 111a2 may be provided as a pair on both sides of the mid-case 111. The off-gas inlets 111a1 and 111a2 may be included on both sides in a longitudinal direction (a left and right direction in the drawing) of the mid-case 111 on the one side of the mid-case 111. Of course, a plurality of (three or more) off-gas inlets may be included according to a design.

[0054] In an embodiment of the present invention, the off-gas inlets 111a1 and 111a2 may be formed in a substantially vertical direction on one surface of the mid-case 111. “Substantially vertical direction” means that a certain range of a design error that occurs at the time of manufacturing is included.

[0055] An off-gas discharged from the fuel cell stack S flows into the membrane humidifier 100 through the off-gas supply flow path P30 and the off-gas inlets 111a1 and 111a2. The off-gas supply flow path P30 is branched into a first off-gas branch flow path P31 and a second off-gas branch flow path P32. The off-gas discharged from the fuel cell stack S flows into the pair of off-gas inlets 111a1 and 111a2 while flowing through the off-gas supply flow path P30, the first off-gas branch flow path P31, and the second off-gas branch flow path P32.

[0056] If necessary, a flow adjustment means 140 for adjusting a flow rate of the off-gas to the first off-gas branch flow path P31 and the second off-gas branch flow path P32 may be installed between the first off-gas branch flow path P31 and the second off-gas branch flow path P32. The flow adjustment means 140 may be, for example, a valve.

[0057] Meanwhile, an inner space of the mid-case 111 may be partitioned into a first space S1 and a second space S2 by partition walls 114. The partition walls 114 can prevent the off-gas flowing into the first off-gas inlet 111a1 from directly flowing into the second off-gas inlet 111a2 by bypassing without performing moisture exchange with the hollow fiber membrane 112.

[0058] In an embodiment of the present invention, the off-gas outlet 111b may be connected to the off-gas discharge flow path P40 and formed as a single off-gas outlet on a surface opposite to the surface on which the off-gas inlets 111a1 and 111a2 are formed. For example, when the pair of off-gas inlets 111a1 and 111a2 are formed on an upper surface of the mid-case 111, the off-gas outlet 111b may be formed on a lower surface of the mid-case 111.

[0059] Further, the off-gas outlet 111b may be formed between the partition walls 114 for partition into the first space S1 and the second space S2. When the off-gas outlet 111b is formed in the first space S1 or the second space S2, an off-gas flowing into the off-gas inlets 111a1 or 111a2 may be directly discharged to the outside through the off-gas outlet 111b without performing moisture exchange with the hollow fiber membrane 112.

[0060] For example, when the off-gas outlet 111b is formed in the first space S1 in FIG. 2, the off-gas flowing into the inside through the first off-gas branch flow path P31 and the first off-gas inlet 111a1 may flow directly to the off-gas outlet 111b without sufficiently exchanging moisture in the first space S1.

[0061] Therefore, the off-gas outlet 111b is preferably formed between the first space S1 and the second space S2. The off-gas outlet 111b is preferably formed between the partition walls 114 for partition into the first space S1 and the second space S2.

[0062] Next, an off-gas flow in the fuel cell membrane humidifier according to the embodiment of the present invention will be described with reference to FIG. 3. FIG. 3 is a view conceptually illustrating the off-gas flow in the fuel cell membrane humidifier according to the embodiment of the present invention. In FIG. 3, the off-gas flow is shown as flowing while surrounding the outside of the hollow fiber membranes 112, but the off-gas flow is not limited thereto and may flow into a bundle of the hollow fiber membranes 112, which is not illustrated for convenience of description.

[0063] The off-gas discharged from the fuel cell stack S flows into the pair of off-gas inlets 111a1 and 111a2 while flowing through the off-gas supply flow path P30, the first off-gas branch flow path P31, and the second off-gas branch flow path P32

[0064] The off-gas flowing into the first off-gas branch flow path P31 and the first off-gas inlet 111a1 performs moisture exchange with the hollow fiber membrane 112 to humidify the dry gas while flowing through the first space S1, and the off-gas flowing into the second off-gas branch flow path P32 and the second off-gas inlet 111a2 exchanges moisture with the hollow fiber membrane 112 to humidify the dry gas while flowing in the second space S2.

[0065] The off-gas that has performed the moisture exchange in the first space S1 and the second space S2 is discharged to the outside through the off-gas outlet 111b formed between the first space S1 and the second space S2 and the off-gas discharge flow path P40.

[0066] According to the related art, it takes a considerable amount of time to flow into the inside through the off-gas inlet 11aa and then be discharged through the off-gas outlet 11ab, and the concentration of the material to be transmitted through the hollow fiber membrane gradually decreases as the off-gas flows from the off-gas inlet 11aa to the off-gas outlet 11ab, and an amount of material to be transmitted through the hollow fiber membrane disposed on the off-gas outlet flab side also gradually decreases, resulting in a decrease in overall efficiency of the fuel cell,

[0067] whereas, according to the embodiment of the present invention, since the off-gas flows into the inside in both directions through the off-gas inlets 111a1 and 111a2 included on both the sides of the one side of the mid-case 111, respectively, and the off-gas flowing into the inside in both the directions flows toward the off-gas outlet 111b formed in an intermediate portion, it is possible to minimize a decrease in concentration of the material to be transmitted through the hollow fiber membrane and improve the overall efficiency of the fuel cell.

[0068] Next, a fuel cell membrane humidifier and a fuel cell system comprising the same according to another embodiment of the present invention will be described with reference to FIG. 4. FIG. 4 is a view illustrating the fuel cell membrane humidifier and the fuel cell system comprising the same according to the other embodiment of the present invention.

[0069] Referring to FIG. 4, in the fuel cell membrane humidifier 200 according to the other embodiment of the present invention, inclined off-gas inlets 211a1 and 211a2 may be included as a pair on both sides of a mid-case 111, and the one pair of inclined off-gas inlets 211a1 and 211a2 may be formed in a direction inclined at a preset angle with respect to one surface of the mid-case 111.

[0070] More specifically, the inclined off-gas inlets 211a1 and 211a2 are formed so that lower ends of the inclined off-gas inlets 211a1 and 211a2 are inclined toward potting portions 113 so that an off-gas flows toward the potting portions 113.

[0071] When the inclined off-gas inlets 211a1 and 211a2 are formed to be inclined toward the potting portions 113, the off-gas flows into the inside while forming an inclination toward the potting portions 113. Therefore, since the off-gas initially flows in the potting portions 113, and then turns in the potting portions 113 to flow in opposite directions, it is possible to increase a flow time in the humidification module 110 and improve the overall humidification efficiency. Of course, a plurality of (three or more) off-gas inlets may be included according to a design.

[0072] Next, an off-gas flow in the fuel cell membrane humidifier according to the other embodiment of the present invention will be described with reference to FIG. 5. FIG. 5 is a view conceptually illustrating the off-gas flow in a fuel cell membrane humidifier according to the other embodiment of the present invention. In FIG. 5, the off-gas flow is shown as flowing while surrounding the outside of the hollow fiber membranes 112, but the off-gas flow is not limited thereto and may flow into a bundle of the hollow fiber membranes 112, which is not illustrated for convenience of description.

[0073] While an off-gas discharged from a fuel cell stack S flows into the pair of inclined off-gas inlets 211a1 and 211a2 while flowing through an off-gas supply flow path P30, a first off-gas branch flow path P31, and a second off-gas branch flow path P32.

[0074] The off-gas flowing through the first off-gas branch flow path P31 and the first inclined off-gas inlet 211a1 initially flows in the potting portion 113 in a first space S1, turns in the potting portion 113 to flow in an opposite direction, and performs moisture exchange with the hollow fiber membranes 112 to humidify the dry gas. The off-gas flowing through the second off-gas branch flow path P32 and the second inclined off-gas inlet 211a2 initially flows in the potting portion 113 in a second space S2, turns in the potting portion 113 to flow in an opposite direction, and performs moisture exchange with the hollow fiber membranes 112 to humidify the dry gas.

[0075] The off-gas that has performed the moisture exchange in the first space S1 and the second space S2 is discharged to the outside through an off-gas outlet 111b formed between the first space S1 and the second space S2, and an off-gas discharge flow path P40.

[0076] According to another embodiment of the present invention, since the off-gas initially flows in the potting portions 113, and then turns in the potting portions 113 to flow in opposite directions, it is possible to increase a flow time in the humidification module 110 and improve the overall humidification efficiency.

[0077] Further, since the off-gas flows into the inside in both the directions through the inclined off-gas inlets 211a1 and 211a2 included on both sides of one surface of the mid-case 111, and the off-gas flowing into the inside in both the directions flows toward the off-gas outlet 111b formed at the intermediate portion, it is possible to minimize a decrease in concentration of a material to be transmitted through the hollow fiber membranes and improve the overall efficiency of the fuel cell.

[0078] Although the embodiments of the present invention have been described above, those skilled in the art can variously modify or change the present invention through affixation, change, deletion, addition, or the like of components without departing from the spirit of the present invention described in the claims, and this will be said to be also included within the scope of the present invention.

DETAILED DESCRIPTION OF MAIN ELEMENTS

[0079] 100: fuel cell membrane humidifier [0080] 110: humidification module [0081] 111: mid-case [0082] 112: hollow fiber membrane [0083] 113: potting portion [0084] 114: partition wall [0085] 111a1, 111a2: off-gas inlet [0086] 211a1, 211a2: inclined off-gas inlet [0087] 111b: off-gas outlet [0088] B: blower [0089] S: fuel cell stack [0090] P10: dry gas supply flow path [0091] P20: humidified gas supply flow path [0092] P30: off-gas supply flow path [0093] P31: first off-gas branch flow path [0094] P32: second off-gas branch flow path [0095] P40: off-gas discharge flow path