JP2009289580A - Humidifying device of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a humidifying device of a fuel cell, which can suppress film twist by adjusting a gas flow rate flowing in a hollow fiber bundle, can improve humidifying efficiency and can reduce pressure loss. <P>SOLUTION: The humidifying device includes the hollow fiber membrane bundle and a housing case 6 with both open ends where a plurality of gas holes 10 to introduce gas into the hollow fiber membrane bundle are formed in mutually opposing faces. The device includes a hollow fiber membrane module in which the hollow fiber membrane bundle is housed in this housing case 6, and a housing which includes an introduction port and an exhaust port of a first gas, and an introduction port and an exhaust port of a second gas, and houses the whole hollow fiber membrane module inside. Then, in this humidifying device, an inner bypass flow passage 28 to split one part of the second gas introduced into the hollow fiber bundle through the gas holes 10 is installed between an inner wall face 12a of a cabinet 12 to constitute the housing and an outer wall face 6a of the housing case 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a humidifier for a fuel cell, and more particularly to a technique for preventing a twist of a hollow fiber membrane caused by a gas flowing into a hollow fiber membrane bundle.

  Conventionally, a humidifier using a hollow fiber membrane is known as a humidifier suitably used in, for example, a fuel cell system (see, for example, Patent Document 1). A humidifier using a hollow fiber membrane uses a capillary condensation action to the pores inside the hollow fiber membrane to separate moisture from the moist gas flowing inside the hollow fiber membrane and move it to the outside of the hollow fiber membrane. It humidifies the dry gas flowing outside the yarn membrane. The wet gas may flow outside the hollow fiber membrane, and the dry gas may flow inside the hollow fiber membrane.

  In the fuel cell system, such a humidifying device performs water exchange between a wet gas rich in water vapor discharged from the fuel cell stack and a dry dry gas before being supplied to the fuel cell stack, It is used as a humidifier for humidifying dry gas.

  In this case, the humidifier is configured to have a hollow fiber membrane module in which, for example, a bundle of hollow fiber membranes is housed in a cylindrical casing, and the humidifier is hollow so that wet gas flows from the wet gas introduction pipe into the hollow fiber membrane. The dry gas is allowed to flow into the yarn membrane module, and the dry gas flows from the dry gas introduction pipe to the outside of the hollow fiber membrane through a plurality of dry gas inflow holes formed at predetermined intervals over the entire circumference of the housing. Into the hollow fiber membrane module. The wet gas and the dry gas are introduced by a so-called cross flow method in which the wet gas and the dry gas are supplied so as to be orthogonal to each other.

And the moisture of the moisture gas permeate | transmits out of a hollow fiber membrane by the difference in the water vapor partial pressure inside and outside a hollow fiber membrane, and the dry gas which flows out of a hollow fiber membrane is humidified by this permeated water. Thereafter, the humidified dry gas flows out from the dry gas outlet pipe and is supplied to the fuel cell stack.
JP 2006-289297 A

  However, in the technique described in Patent Document 1, since the gas flowing outside the hollow fiber membrane directly hits the hollow fiber membrane bundle, the wind pressure causes membrane distortion (membrane deformation). The hollow fiber membrane bundle is inserted into a cylindrical casing with a plurality of bundles, and both ends thereof are fixed to the inner wall of the casing with potting resin, but the portions other than both ends are not fixed and thus are introduced. The wind pressure of the gas When the hollow fiber membrane is used, the gas outlet portion is blocked, and all the hollow fiber membranes that serve as the humidification field cannot be used up, resulting in a decrease in humidification efficiency and an increase in pressure loss.

  Therefore, the present invention has been proposed in view of the above-described actual situation, and the flow rate of gas flowing in the hollow fiber membrane bundle is adjusted to suppress membrane swaying, thereby increasing the humidification efficiency and reducing the pressure loss. An object of the present invention is to provide a humidifying device for a fuel cell.

  The present invention includes a first gas that flows through a flow passage formed in a longitudinal direction of the hollow fiber membrane, a second gas that flows outside the hollow fiber membrane in a direction substantially orthogonal to the first gas, Is a cross-flow humidifier that exchanges moisture between the two.

  The humidifier includes a hollow fiber membrane bundle in which a plurality of hollow fiber membranes are bundled, and a storage case in which a plurality of gas holes are formed in both sides of the hollow fiber membrane bundle and the gas is introduced into the hollow fiber membrane bundle on opposite surfaces. A hollow fiber membrane module in which the hollow fiber membrane bundle is housed in a housing case, a first gas inlet and outlet, and a second gas inlet and outlet, the hollow fiber And a housing in which the entire membrane module is accommodated.

  And in this invention, the internal bypass flow path which distributes a part of 2nd gas introduce | transduced in a hollow fiber membrane bundle through a gas hole is provided between the inner wall face of the said housing, and the outer wall face of the said storage case.

  According to the present invention, the internal bypass for diverting a part of the second gas introduced into the hollow fiber membrane bundle is provided between the inner wall surface of the housing and the outer wall surface of the storage case. The part is diverted to the internal bypass, the wind pressure of the second gas introduced into the hollow fiber membrane bundle is reduced, and the membrane is prevented from twisting. Therefore, according to the humidifier of the present invention, the humidification efficiency can be increased and the pressure loss can be reduced.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

“Explanation of humidifier configuration”
1 is an overall perspective view showing an example of a humidifier, FIG. 2 is an exploded perspective view of FIG. 1, FIG. 3 is a perspective view of a hollow fiber membrane bundle, FIG. 4 is a perspective view of a storage case, and FIG. FIG. 6 is a view when FIG. 5 is viewed from the direction of arrow B, FIG. 7 is a view when FIG. 5 is viewed from the direction of arrow C, and FIG. FIG. 9 is a perspective view of the second gas introduction manifold, FIG. 10 is a view showing the inflow / outflow state of the first gas and the second gas flowing in the humidifier, and FIG. 11 is a diagram showing the relationship between the operating load of the fuel cell and the amount of humidification.

  The fuel cell connected to the humidifier of the present embodiment electrochemically reacts a fuel gas such as hydrogen gas and an oxidizing gas containing oxygen through an electrolyte, and generates electric energy from between electrodes provided on both surfaces of the electrolyte. It is to be taken out directly. In particular, solid polymer fuel cells using solid polymer electrolytes are attracting attention as power sources for electric vehicles because of their low operating temperature and easy handling.

  That is, a fuel cell vehicle is equipped with a hydrogen storage device such as a high-pressure hydrogen tank, a liquid hydrogen tank, or a hydrogen storage alloy tank in the vehicle, and reacts by supplying hydrogen supplied therefrom and air containing oxygen to the fuel cell. The motor connected to the driving wheel is driven by the electric energy extracted from the fuel cell. Therefore, the fuel cell vehicle is an ultimate clean vehicle that uses only water as an emission material.

  In order for the solid polymer electrolyte used in such a fuel cell to exhibit good hydrogen ion conductivity, it is necessary to humidify the solid polymer electrolyte and maintain it in a wet state. In order to realize this, a pure water path is provided in the fuel cell main body, and internal humidification for humidifying the electrolyte in the fuel cell main body and external humidification for humidifying the hydrogen gas or air supplied to the fuel cell are performed.

  As a humidifier for external humidification, a hollow fiber that exchanges humidity between a high-humidity exhaust gas discharged from a fuel cell and a hydrogen or air dry supply gas supplied to the fuel cell via a hollow fiber membrane A membrane-type humidifier is used. The hollow fiber membrane type humidifier is not particularly necessary for humidification water and energy for humidification, and is therefore particularly suitable for in-vehicle use that requires a reduction in size and weight.

  As shown in FIGS. 1 to 3, the humidifying device 1 of the present embodiment is a hydrogen gas or air (hereinafter referred to as a second gas G2) containing abundant moisture, specifically, water vapor discharged from the fuel cell. )) And dry gas, specifically hydrogen gas or air (hereinafter referred to as first gas G1) to be supplied to a fuel cell pressurized and heated by a compressor, moisture exchange is performed. A hollow fiber membrane module 2 using a hollow fiber membrane as a water permeable membrane (a hollow fiber membrane bundle and a storage case for housing it), and the entire hollow fiber membrane module 2. And a housing 3 housed inside.

  In the water permeable membrane type humidifier 1, for example, a first gas G1 which is a dry gas is supplied into the hollow fiber membrane (flow passage formed in the inside thereof in the longitudinal direction of the membrane). When the second gas G2, which is a wet gas containing moisture, is supplied to the outside (outside) of the hollow fiber membrane, the moisture is condensed in the pores (capillaries) formed in the thickness direction in the hollow fiber membrane. (Capillary condensation) and moisture permeates from the outside to the inside of the hollow fiber membrane due to the difference in water vapor partial pressure inside and outside the hollow fiber membrane. The flow of air is inhibited by the condensation of moisture in the pores in the hollow fiber membrane, and as a result, only water vapor in the wet gas is selectively transmitted to the dry gas side. This permeated moisture is humidified by contacting with the dry gas supplied to the inside of the hollow fiber membrane bundle and evaporating.

  In addition to the above-described case, the moisture permeation can be performed in either of the cases where the second gas G2 that is a wet gas is caused to flow inside the hollow fiber membrane and the first gas G1 that is a dry gas is allowed to flow outside the hollow fiber membrane. Exchange is performed. In the present embodiment, the former configuration is adopted. The first gas G1 and the second gas G2 adopt a so-called cross flow method in which the gas flows in directions substantially orthogonal to each other.

  The hollow fiber membrane module 2 includes a hollow fiber membrane bundle 5 formed by bundling a plurality of hollow fiber membranes 4 and a rectangular tubular storage case 6 that accommodates the hollow fiber membrane bundle 5 therein.

  The hollow fiber membrane bundle 5 is composed of a hollow fiber membrane 4 having an elongated straw shape with a circular cross section formed therein with a flow passage 7 which is a pore penetrating in the longitudinal direction, and a plurality of the hollow fiber membranes 4 are formed. Are made into a quadrangular prism shape.

  A first gas G1, which is a dry oxidant gas pressurized and heated by the compressor, is introduced into the flow passage 7 formed in the center of the hollow fiber membrane 4. The hollow fiber membrane 4 is formed by bundling a plurality of fibers into a quadrangular prism shape and then fixing only both ends with a potting agent (adhesive). The hollow fiber membrane bundle 5 excluding both ends has fine voids that are not joined to each other, and the second gas G2 that is a wet gas flows through the voids. That is, a portion excluding both ends of the hollow fiber membrane bundle 5 is a humidification field that humidifies the first gas G1 with the second gas G2.

  As shown in FIG. 4, the storage case 6 is formed as a rectangular tube-shaped case that opens the both ends and stores the hollow fiber membrane bundle 5 therein. On the opposing surfaces 8 and 9 in the longitudinal direction of the storage case 6, the second gas G 2, which is a wet gas discharged from the fuel cell, passes through the outside (outside) of the hollow fiber membrane 4 and the hollow fiber membrane bundle. A plurality of gas holes 10 and 11 for flowing into the interior of 5 (the gaps between the hollow fiber membranes 4) are formed on almost the entire surface.

  The gas hole 10 formed in one surface 8 (this surface is referred to as the second gas introduction surface 8) serves as a gas introduction hole through which the second gas G2 flows into the hollow fiber membrane bundle 5. The gas hole 11 formed in the other surface 9 (this surface is referred to as the second gas discharge surface 9) discharges the second gas G2 emitted from the inside of the hollow fiber membrane bundle 5 to the outside of the hollow fiber membrane module 2. It is a gas discharge hole to be made.

  Note that the hollow fiber membrane module 2 stored in the storage case 6 has both ends in the longitudinal direction fixed to the inner wall surface of the case with a potting agent, but other portions are not bonded.

  The housing 3 includes a housing 12, a first gas introduction manifold 14 having a first gas G1 introduction port 13, a first gas discharge manifold 16 having a first gas G1 discharge port 15, It consists of a second gas introduction manifold 18 having a two-gas G2 introduction port 17 and a second gas discharge manifold 20 having a second gas G2 discharge port 19.

  The housing 12 is formed as a resin case having a quadrangular prism shape with both ends opened to accommodate the entire hollow fiber membrane module 2 therein.

  The first gas introduction manifold 14 is attached so as to close one opening 21 formed in the front-rear direction of the housing 12. The seal between the first gas introduction manifold 14 and the housing 12 is sealed with a shaft seal structure using, for example, an O-ring 22 at the inner end of the opening 21 as shown in FIGS. The first gas introduction manifold 14 is formed with an introduction port 13 for introducing the first gas G1 supplied from the first gas supply tank into the hollow fiber membrane module 2 in the housing 12.

  The first gas discharge manifold 16 is attached so as to close the other opening 23 formed in the front-rear direction of the housing 12. The seal between the first gas discharge manifold 16 and the housing 12 is sealed with a shaft seal structure using, for example, an O-ring 24 at the inner end of the opening 23 as shown in FIGS. The first gas discharge manifold 16 is formed with a discharge port 15 for discharging the first gas G1 that has passed through the flow passage 7 formed at the center of each hollow fiber membrane 4 to the outside of the housing 12. Yes.

  The second gas introduction manifold 18 is attached so as to close an opening (not shown) formed on one side surface of the housing 12. The second gas introduction manifold 18 is formed with an introduction port 17 for introducing the second gas G2, which is a wet gas rich in water vapor discharged from the fuel cell, into the housing 12. The seal between the second gas introduction manifold 18 and the housing 12 is similarly sealed with a shaft seal structure.

  The second gas introduction manifold 18 has a gas introduction passage 25 extending from the introduction port 17 for introducing the second gas G2 to the second gas introduction surface 8 of the storage case 6 in which the gas hole 10 is formed. A step portion 26 is provided in the middle. The step portion 26 is formed by recessing a part of the second gas introduction manifold 18 inward (on the casing 12 side), and is provided in the middle position between the second gas introduction surfaces 8. By providing the step portion 26, the volume of the flow path on the back side of the gas introduction flow path 25 is reduced.

  The second gas G2 flowing from the introduction port 17 flows through the gas introduction flow path 25, collides with the inclined inner wall surface 26a by the step portion 26 provided in the middle thereof, and is dispersed. Therefore, the dispersed second gas G2 is uniformly introduced into the entire second gas introduction surface 8. In other words, the second gas G2 originally tends to be biased to the back side of the gas introduction flow channel 25 due to the characteristics of the gas flow, but is difficult to flow by colliding with the step portion 26 in the middle of the flow channel. It facilitates the flow on the front side to achieve uniform gas distribution.

  The second gas discharge manifold 20 is integrated with the housing 12 on the other side surface of the housing 12. The second gas discharge manifold 20 is provided with a discharge port 19 for discharging the second gas G2 introduced into the housing 12 to the outside of the housing 12. The second gas discharge manifold 20 is provided with an internal space 27 so that a sufficiently large flow path to the discharge port 19 can be secured.

  As described above, the first gas introduction manifold 14, the first gas discharge manifold 16, and the second gas introduction manifold 18 are sealed with the shaft seal structure to the housing 12. Compared to the case where these connecting portions are sealed by other means, the number of bolts can be reduced and the space for the fastening flanges and bosses can be eliminated, which is advantageous for downsizing the humidifier configuration.

  In particular, in the humidifier 1, the internal bypass flow path 28 for diverting a part of the second gas G 2 introduced into the hollow fiber membrane bundle 5 through the gas hole 10 is provided with the inner wall surface of the housing 3 and the storage case 6. It is provided between the outer wall surfaces. As shown in FIG. 8, the internal bypass passage 28 is a space formed between the inner wall surface 12 a of the housing 12 and the outer wall surface 6 a of the storage case 6. More specifically, a shallow groove 29 is formed on the inner wall surface 12a of the housing 12 excluding both ends where the openings 21 and 23 are formed, so that a gap between the groove 29 and the outer wall surface 6a of the storage case 6 is formed. A space portion serving as a passage is formed. This space portion serves as an internal bypass flow path 28.

  The internal bypass channel 28 is provided at two positions above and below the second gas G2 introduced into the hollow fiber membrane bundle 5 through the gas holes 10 formed in the storage case 6. In other words, in the upper and lower portions of the casing height direction E perpendicular to the second gas flow direction D through which the second gas G2 flows from the second gas introduction surface 8 to the second gas discharge surface 9 of the storage case 6, An internal bypass channel 28 is provided for each. The second gas G2 that is diverted to the internal bypass channel 28 flows up and down on the outside with the hollow fiber membrane module 2 interposed therebetween.

  The flow path length L1 of the internal bypass flow path 28 is shorter than the vertical length L2 of the hollow fiber membrane module 2 in the direction orthogonal to the internal bypass flow path 28. With this relationship, the flow path distance of the second gas G2 diverted to the internal bypass flow path 28 can be shortened, and the water vapor concentration gradient as the humidification field of the gas flowing in the hollow fiber membrane bundle 5 can be reduced. It becomes.

  As shown in the enlarged view of FIG. 6, the internal bypass channel 28 includes a seal member 29 formed over the entire circumference of the outer wall surface 6 a at both ends of the storage case 6 and the inside of the housing 12. Gas leakage is prevented by the close contact with the wall surface 12a. The seal member 29 is disposed between the two annular protrusions 30 and 31 formed on the outer wall surface 6 a on both ends of the opening of the storage case 6. As the seal member 29, for example, an O-ring or the like is used. The internal bypass passage 28 is sealed with a shaft seal structure, similar to the seal structure between the first gas introduction manifold 14, the first gas discharge manifold 16, the second gas introduction manifold 18 and the housing 12. ing. The annular protrusions 30 and 31 are belt-like protrusions having a low height that are in close contact with the inner wall surface 12 a of the housing 12. As described above, by setting the sealing position of the internal bypass flow path 28 to both end positions of the hollow fiber membrane module 2, the flow path space of the internal bypass flow path 28 can be effectively used.

  A flow rate adjusting means for adjusting the flow rate of the second gas G2 flowing through the internal bypass flow path 28 is provided on the inlet side of the internal bypass flow path 28. As shown in FIG. 4, the flow rate adjusting means is a ridge formed on the outer wall surface 12 a of the casing 12 so as to connect the seal members 29 formed on the entire outer wall surface of the both ends of the casing 12. Part 32. Specifically, the ridge portion 32 has a gas flow direction F of the first gas G1 so as to be connected to the annular protrusions 31 at both ends on the upper surface and the lower surface of the storage case 6 adjacent to the second gas introduction surface 8. It is formed along. The ridge portion 32 has the same height as the annular protrusion 31 and serves as a resistance of the second gas G 2 that is diverted to the internal bypass passage 28.

"Explanation of gas flow"
Next, in the humidifying device 1 configured as described above, the gas flow of the first gas G1 and the second gas G2 into the film will be described with reference to FIG. The first gas G1, which is a dry gas, is supplied from the introduction port 13 of the first gas introduction manifold 14 and then flows through the flow passages 7 of the hollow fiber membranes 4 constituting the hollow fiber membrane bundle 5 to form the first gas. The gas is discharged from the discharge port 15 of the discharge manifold 16.

  The second gas G2, which is a wet gas, is supplied from the introduction port 17 of the second gas introduction manifold 18, and then collides with the stepped portion 26 formed in the second gas introduction manifold 18, and is dispersed. A uniform amount is supplied to the entire two gas introduction surfaces 8. The second gas G2 flows through the gaps between the hollow fiber membranes 4 of the hollow fiber membrane bundle 5 through the gas holes 10 formed in the second gas introduction surface 8, and then the second gas discharge on the opposite side. The gas is discharged from each gas hole 11 formed in the surface 9.

  In the humidification field, the first gas G1 which is a dry and dry gas flowing through the flow passage 7 of the hollow fiber membrane 4 and the second gas G2 which is a wet gas containing moisture flowing through the gap between the hollow fiber membranes 4 are in contact with each other. The water permeates from the outside to the inside of the hollow fiber membrane 4 due to the difference in water vapor partial pressure inside and outside the hollow fiber membrane 4. Thereby, the water vapor in the wet gas permeates to the dry gas side and humidifies the first gas G1.

  In addition, a part of the second gas G <b> 2 that has collided with the stepped portion 26 and dispersed flows into the upper and lower internal bypass channels 28. At the inlet of the internal bypass passage 28, the divided second gas G2 collides with the ridges 32, which are flow rate adjusting means, and the flow rate is adjusted.

  Then, the second gas G2 discharged from the gas hole 11 of the second gas discharge surface 9 and the second gas G2 flowing out of the upper and lower internal bypass passages 28 merge at the second gas discharge manifold 20. The merged second gas G2 is uniformly mixed because the sufficiently large internal space 27 formed in the second gas discharge manifold 20 is provided. The uniformly mixed second gas G <b> 2 is discharged from the discharge port 19 formed in the second gas discharge manifold 27.

  By the way, in the humidification device 1, when a part of the second gas G2 flowing in from the inlet 17 of the second gas introduction manifold 18 is diverted to the internal bypass flow path 28, the gas flow rate flowing in the bypass increases. The amount of gas flowing in the hollow fiber membrane bundle 5 serving as a humidification field is reduced, and the humidification efficiency is lowered. In the design of the humidifier, there is a humidification amount suitable for each of a low load, a medium load, and a high load, but humidification control cannot be performed with a generally used film humidifier.

  In a fuel cell vehicle, there is an optimum humidification region in order to balance stack dryout and flooding (see FIG. 11). Stack dry out means that the polymer membrane of the solid polymer electrolyte membrane is too dry. Flooding means that the polymer film contains too much moisture. A humidifier that can effectively use the optimum region is defined as having high humidification efficiency (the size does not become large and the specifications are satisfied with a compact structure).

  In FIG. 11, the hatched area is a flooding area, and the hatched area is a dryout area.

  The humidifying performance of the humidifier can be evaluated by the water vapor transfer rate (flux) per unit membrane area. In the contact type, not only the local film water vapor transfer coefficient but also the water vapor concentration varies depending on the flow direction. The water vapor moving speed is obtained by integrating the water vapor permeation flux along the flow direction. Looking at the fit with the empirical formula, the humidification performance changes in an exponential function with respect to the flow velocity when other parameters are constant. A normal humidification film changes in an exponential function with respect to flow rate sensitivity (≈operating load), and thus becomes an overhumidified region as indicated by a line J in FIG. On the other hand, in the humidifying device 1 of the present embodiment provided with the internal bypass flow path 28, when designed in the rated condition region equivalent to the conventional configuration, as shown by the line K in FIG. By reducing the flow rate of gas flowing in the membrane in the middle load range, the amount of humidification at a low load is reduced, and excessive humidification can be suppressed.

  The internal bypass flow path 28 in the humidifying device 1 of the present embodiment is an internal bypass in the housing 3 between the housing 12 and the hollow fiber membrane module 2, and has a structure that allows the bypass amount of the second gas G2 to flow without variation. ing. By designing the amount of humidification under high load and determining the amount of bypass, the optimum amount of humidification can be maintained in the entire operation range, and pressure loss can be reduced. In general membrane humidifiers, when the amount of humidification at a high load is designed, it is not a specification that increases the original humidification efficiency, such as excessive humidification at a low load. In the case of an external bypass structure that bypasses the outside of the housing 3, the humidifier becomes large due to the external bypass, the external bypass is cooled by outside air, and condensed water is generated in the bypass flow path. , Distribution variation after merging will occur.

"Effect"
According to the humidifying device of the present embodiment, the internal bypass flow path 28 for diverting a part of the second gas G2 introduced into the hollow fiber membrane bundle 5 through the gas holes 10 is provided in the housing 12 constituting the housing 3. Since it is provided between the wall surface 12 a and the outer wall surface 6 a of the storage case 6, a part of the second gas G <b> 2 is diverted into the internal bypass channel 28, thereby being introduced into the hollow fiber membrane bundle 5. The wind pressure of the second gas G2 is reduced, and the film is prevented from being twisted.

  Therefore, according to the humidifying device of this embodiment, since almost all the hollow fiber membranes 4 function without being swung, the humidifying efficiency can be increased. Moreover, according to this embodiment, since the flow rate of the gas flowing in the hollow fiber membrane bundle 5 is reduced, the pressure loss can be reduced, and the membrane breakage (fatigue failure) life of the hollow fiber membrane 4 can be extended. Similarly, the load on the resin that bonds (potts) both ends of the hollow fiber membrane 4 is reduced.

  Further, according to the humidifier of the present embodiment, unlike the external bypass that bypasses the outside of the housing 12, the internal bypass flow path 28 is provided inside the housing 12, so that the bypass portion touches the outside air. Since supply gas temperature does not fall, it can prevent that wet gas (2nd gas G2) condenses. Moreover, according to this embodiment, unlike the external bypass, the space efficiency as a humidifier can be utilized effectively.

  Further, according to the humidifier of the present embodiment, the low load (low flow rate) side is in an excessively humidified state, but the amount of gas flowing into the hollow fiber membrane bundle 5 can be reduced by the internal bypass flow path 28. Out and below zero startability can be balanced.

  According to the humidifying device of the present embodiment, the internal bypass flow paths 28 are provided at two positions above and below the second gas G2 introduced into the hollow fiber membrane bundle 5 through the gas holes 10, so that the two The second gas G2 can be diverted into the internal bypass passage 28, and the second gas G2 can be prevented from flowing into the hollow fiber membrane bundle 5 in a concentrated manner.

  According to the humidifier of the present embodiment, the flow path length L1 of the internal bypass flow path 28 is shorter than the vertical length L2 of the hollow fiber membrane module 2 in the direction orthogonal to the internal bypass flow path 28. The distance of the gas flowing through the flow path is shortened, and the wet gas is prevented from becoming condensed water. Thereby, since a water vapor | steam density | concentration gradient becomes small, it becomes possible to raise humidification efficiency more.

  According to the humidifying device of the present embodiment, the inner case 12 flows in the inner bypass flow path 28 in close contact with the inner wall surface 12a of the housing 12 constituting the housing over the entire circumference of the open outer wall surfaces 6a at both ends. Since the seal member 29 for preventing the leakage of the second gas G2 is provided, the seal is provided at a place where the influence of the displacement due to the internal pressure is the least, and the reliability of preventing the internal leak is improved. In addition, according to the present embodiment, since the shaft seal structure is employed, the number of bolts can be reduced and the space for the fastening flanges and bosses can be eliminated as compared with the case of sealing by other means, which is advantageous for downsizing the humidifier configuration. become.

  According to the humidifier of the present embodiment, the step portion 26 is provided in the middle of the gas introduction passage 25 from the introduction port 17 of the second gas G2 to the second gas introduction surface 8 of the storage case 6 in which the gas hole 10 is formed. Since the second gas G2 collides with the step portion 26 and is uniformly dispersed over the second gas introduction surface 8, the second gas G2 is concentrated in one place on the hollow fiber membrane bundle 5 The second gas G2 flows uniformly into the entire hollow fiber membrane bundle 5. Therefore, the gas flow rate of the second gas G2 flowing into the hollow fiber membrane bundle 5 can be made uniform, pressure loss can be reduced, the life can be extended by preventing the hollow fiber membrane from being cut, and the humidification performance can be improved.

  According to the humidifier of this embodiment, a part of the second gas introduction manifold 18 is recessed inward to form the stepped portion 26 to reduce the flow volume on the back side of the flow path, and the stepped portion 26 is Since it was provided in front of the intermediate position of the two gas introduction surface 8, the second gas G2 can be made to flow evenly on the front side of the flow path that is difficult to flow.

  According to the humidifier of the present embodiment, the flow rate adjusting means for adjusting the flow rate of the second gas G2 flowing through the internal bypass flow path 28 is provided on the inlet side of the internal bypass flow path 28. The amount of gas flowing into the internal bypass passage 28 can be adjusted.

  According to the humidifier of the present embodiment, the flow rate adjusting means is a ridge formed on the outer wall surface 6a so as to connect between the seal members 29 formed on the entire outer peripheral wall surfaces of both ends of the housing 12 constituting the housing 3. Since it comprises the part 30, the flow rate adjusting means can be constructed with a simple structure.

"Other embodiments"
For example, the shape of the hollow fiber membrane module 2 may be a generally used cylindrical shape or an oval shape according to restrictions on the position of the humidifier space to be mounted. In the above-described embodiment, since the rectangular tube-shaped hollow fiber membrane module 2 is accommodated in the same rectangular tube-shaped housing 3, a space for attaching other fuel cell components to the housing 3 is also created. Can be increased.

  In the above-described embodiment, the step portion 26 is formed by indenting a part of the second gas introduction manifold 18. However, a guide plate for restricting the flow path is provided in the gas introduction flow path 25. May be used instead of the stepped portion. Alternatively, a rectifying plate such as punching metal may be provided in the middle of the gas introduction flow path 25, and this rectifying plate may be used in place of the step portion 26.

  In addition, two hollow fiber membrane modules 2 are prepared, and these hollow fiber membrane modules 2 and 2 are arranged vertically with a predetermined space, so that the space between the hollow fiber membrane modules 2 and 2 is internally bypassed. The flow path 28 can also be used. By doing so, three internal bypass flow paths 28 in the vertical and central directions are obtained.

FIG. 1 is an overall perspective view showing an example of a humidifier. 2 is an exploded perspective view of FIG. FIG. 3 is a perspective view of a hollow fiber membrane bundle. FIG. 4 is a perspective view of the storage case. FIG. 5 is a cross-sectional view taken along line AA of FIG. FIG. 6 is a view when FIG. 5 is viewed from the direction of arrow B. FIG. FIG. 7 is a view when FIG. 5 is viewed from the direction of arrow C. FIG. FIG. 8 is a view showing an internal bypass provided between the inner wall surface of the housing and the outer wall surface of the storage case. FIG. 9 is a perspective view of the second gas introduction manifold. FIG. 10 is a view showing the inflow / outflow state of the first gas and the second gas flowing in the humidifier. FIG. 11 is a diagram showing the relationship between the operating load of the fuel cell and the amount of humidification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Humidifier 2 ... Hollow fiber membrane module 3 ... Housing 4 ... Hollow fiber membrane 5 ... Hollow fiber membrane bundle 6 ... Storage case 7 ... Flow path 8 ... 2nd gas introduction surface 9 ... 2nd gas discharge surface 10, 11 ... Gas hole 12 ... Case 14 ... First gas introduction manifold 16 ... First gas discharge manifold 18 ... Second gas introduction manifold 20 ... Second gas discharge manifold 25 ... Gas introduction flow path 26 ... Step 28 ... Internal bypass flow path 29 ... Seal member

Claims (8)

Moisture between the first gas flowing through the flow passage formed inside the hollow fiber membrane in the longitudinal direction and the second gas flowing outside the hollow fiber membrane in a direction substantially perpendicular to the first gas. In the humidifying device of the fuel cell to be replaced,
A hollow fiber membrane bundle in which a plurality of hollow fiber membranes are bundled, and a storage case in which both ends are opened and a plurality of gas holes for introducing gas into the hollow fiber membrane bundle are formed on opposite surfaces. A hollow fiber membrane module in which the hollow fiber membrane bundle is housed in a case; a first gas introduction port and discharge port; and a second gas introduction port and discharge port. A housing that is housed,
An internal bypass passage for dividing a part of the second gas introduced into the hollow fiber membrane bundle through the gas hole is provided between the inner wall surface of the housing and the outer wall surface of the storage case. A fuel cell humidifier. A fuel cell humidifier according to claim 1,
The humidifying device for a fuel cell, wherein the internal bypass channel is provided at two positions above and below the second gas introduced into the hollow fiber membrane bundle through the gas hole. A humidifying device for a fuel cell according to claim 1 or 2,
A humidifying device for a fuel cell, characterized in that a flow path length of the internal bypass flow path is shorter than a vertical length of the hollow fiber membrane module in a direction orthogonal to the internal bypass flow path. A humidifying device for a fuel cell according to any one of claims 1 to 3,
A seal member is provided over the entire circumference of the outer wall surfaces at both ends of the storage case, which is in close contact with the inner wall surface of the housing and prevents leakage of the second gas flowing through the internal bypass flow path. Fuel cell humidifier. A humidifying device for a fuel cell according to any one of claims 1 to 4,
A step portion is provided in the middle of the gas introduction flow path from the second gas introduction port to the second gas introduction surface of the storage case in which the gas hole is formed, and the second gas is caused to collide with the step portion. A fuel cell humidifier characterized by being uniformly dispersed over the entire second gas introduction surface. A humidifying device for a fuel cell according to claim 5,
The gas introduction flow path is formed in a second gas introduction manifold attached to the housing, and a part of the second gas introduction manifold is recessed inward to form a stepped portion on the back side of the flow path. A humidifying device for a fuel cell, wherein the flow path volume is reduced and the step portion is provided in front of an intermediate position of the second gas introduction surface. A humidifying device for a fuel cell according to any one of claims 4 to 6,
A humidifying device for a fuel cell, characterized in that a flow rate adjusting means for adjusting a flow rate of the second gas flowing through the internal bypass channel is provided on the inlet side of the internal bypass channel. A humidifying device for a fuel cell according to claim 7,
The humidifying device for a fuel cell, wherein the flow rate adjusting means comprises a ridge formed on an outer wall surface of the housing so as to connect between seal members formed on the entire outer wall surfaces of both ends of the housing. .

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