JP2008243417A - Humidifier for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance heat insulation performance for each single humidifier constituting a humidifier humidifying with the use of a vapor permeation film, restrain temperature distribution in the laminating direction that tends to occur at normal operation, and enhance heat efficiency by shortening the temperature rise time, at the beginning of humidification. <P>SOLUTION: In forming a single humidifier by integrating a vapor-permeating film integral seal 1, a humidified-side separator 11, and a humidifying-side separator 12, protruded parts 9 of the inner periphery and the outer periphery of each manifold 5, 7, 8 in a frame body 3 cover outer periphery parts of manifolds 10, shaped like glasses connected to the humidifying-side separator 12 only at a flow channel guide-in part, and communicate with the flow channel guide-in part 10a of the manifold 10 of the humidifying-side separator 12 and a guide-in flow channel 5a at an inner periphery of the manifold 8 of the frame body 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell humidifier applied to a polymer electrolyte fuel cell that generates power using a fuel fluid and an oxidant fluid.

  In a fuel cell system, it is known that power generation and heat generation are performed by reacting a fuel gas containing hydrogen and an oxidant gas containing oxygen in the fuel cell. The heat generated by the fuel cell is conveyed by circulating cooling water, the temperature of the fuel cell is maintained within a predetermined temperature range suitable for power generation, and the heat of the cooling water is used in a water heater or the like. As a result, the energy efficiency of the fuel cell system is improved. Further, in the fuel cell system, in order to change the power generation amount according to the required power amount, the operating state is changed by adjusting the fuel gas flow rate, the oxidant gas flow rate, the cooling water flow rate, and the like.

  In a polymer electrolyte fuel cell, a solid polymer electrolyte membrane having proton conductivity is used as an electrolyte. This solid polymer electrolyte membrane needs to be in a wet state, and in a dry state or a damp state, the proton conductivity Since the power generation performance is deteriorated due to the deterioration, at least one of the fuel gas and the oxidant gas is humidified by the humidifying means and supplied to the fuel cell.

  A fuel cell using a solid polymer electrolyte has an electric power generated by electrochemically reacting a humidified and temperature-controlled hydrogen-containing fuel gas with an oxygen-containing oxidant gas such as humidified and temperature-controlled air. And heat are generated simultaneously. In general, in order to supply fuel gas and oxidant gas that are humidified and temperature-controlled, a humidified gas (fluid) is supplied to either one of the frame that is integrally formed with a water vapor permeable membrane and a sealing material. A fuel cell humidifier configured by stacking a plurality of single humidifiers including a pair of separators having a flow path for discharging and a flow path for supplying and discharging humidified gas on the other side is used. The humidified fluid here may be off-gas from the stack or cooling water.

  A gas seal material and a gasket are arranged with a water vapor permeable membrane interposed so that the supplied fuel gas and oxidant gas do not leak to the outside and the two gases are not mixed with each other. A separator for mechanically fixing the water vapor permeable membrane and connecting adjacent water vapor permeable membranes to each other in series is disposed outside the water vapor permeable membrane. In the portion of the separator that comes into contact with the water vapor permeable membrane, a space and a flow path for supplying the reaction gas to the humidified side are formed. In general, the space and the flow path are formed by providing grooves on the surface of the separator. Furthermore, it is practical by stacking a plurality of single humidifiers composed of a pair of separators and connecting the water vapor permeable membranes in series to each other, with a water vapor permeable membrane and a frame body integrally formed with a sealing material. It is common to increase the humidifying ability to a certain extent.

  Each single humidifier has manifold holes, and a manifold is formed by stacking these manifold holes. The fluid supplied from the supply pipe is distributed and supplied to each single humidifier through the inlet manifold, and the fluid discharged from each single humidifier is discharged from the discharge pipe through the outlet manifold.

  FIG. 8 is an exploded perspective view of a conventional fuel cell humidifier. 1 is a seal in which a water vapor permeable membrane 2 is integrally formed, 11 is a humidified separator, 12 is a humidified separator, and 21 is a discharge pipe. Each of which is provided with manifolds 5, 7, 8, 10, a single humidifier composed of the seal 1, the humidifier-side separator 11, and the humidifier-side separator 12, an end module 21, Are connected to each other by fastening bolts and nuts 20, 22, 23, and the like to form a unit.

  However, since the humidifier is heated by warm water, there is a problem that the fluid in the manifold is affected and temperature distribution occurs in the stacking direction. That is, the rate of heat dissipation from the end surface is large at the end in the stacking direction of the single humidifier and tends to be relatively low, and the rate of heat dissipation is small at the center in the stacking direction and tends to be relatively high. In other words, variation in the humidification performance tends to occur for each single humidifier.

  If a fluid higher than the appropriate reaction temperature is supplied to the fuel cell, performance degradation due to a decrease in the voltage of the fuel cell or catalyst deterioration tends to occur. If a fluid lower than the appropriate reaction temperature is supplied, flooding due to condensation or gas shortage occurs. , There is a problem in that partial deterioration is induced and catalyst deterioration is easily promoted.

In order to avoid such a problem, various techniques, such as disposing a heat insulating material on at least a part of the inner periphery of the manifold, have been proposed (see, for example, Patent Documents 1 and 2).
JP 2006-196249 A JP 2006-210150 A

  In the prior art, the single humidifier constituting the fuel cell has manifold holes, and a manifold is formed by stacking these manifold holes. The fluid supplied from the supply pipe is distributed and supplied to each single humidifier through the inlet manifold, and the fluid discharged from each humidifier is discharged from the discharge pipe through the outlet manifold.

  However, since the humidifier is heated by warm water, the humidification performance of each single humidifier tends to vary, and if a fluid lower than the appropriate reaction temperature is supplied, flooding due to condensation and gas shortage will occur. , There is a problem that partial polarity reversal is induced and catalyst deterioration is easily promoted.

  For the same reason at the start of operation as well as during such normal operation, the temperature of the fuel cell is raised to an appropriate reaction temperature by means of heating other than the power generation of the fuel cell, for example, by combustion of city gas or an electric heater. There is a need to. However, for practical use, the temperature raising time must be short and the thermal efficiency at the time of temperature raising must be high.

  In order to solve the above-described conventional problems, the present invention suppresses the temperature distribution in the stacking direction, which is likely to occur during normal operation, by increasing the heat insulation performance for each humidifier constituting the fuel cell humidifier, and at the start of humidification An object of the present invention is to provide a fuel cell humidifier capable of shortening the temperature raising time and improving the thermal efficiency.

  In order to achieve the above object, the invention described in claim 1 is used in a polymer electrolyte fuel cell that generates power using a fuel fluid and an oxidant fluid, and at least one of the fuel fluid and the oxidant fluid. In order to humidify, a water vapor permeable membrane, a frame body integrally formed with a sealing material, and a flow path for supplying and discharging the humidified fluid to one of them, and a flow path for supplying and discharging the humidified fluid to the other A fuel cell humidifier configured by laminating a plurality of single humidifiers comprising a pair of separators having a protrusion on the inner and outer periphery of a manifold of the frame, the protrusion being a flow path The introduction part covers the separator manifold connected to the separator humidification part, and the flow path introduction part of the manifold of the separator communicates with the flow path introduction part formed on the inner periphery of the manifold of the frame body. ing With this configuration, the projecting portions of the inner periphery and the outer periphery of the manifold of the frame body cover the separator manifold connected to the separator humidification portion only at the flow channel introduction portion, and the flow path of the manifold of this separator Since the introduction part communicates with the introduction flow path on the inner periphery of the manifold of the frame body, humidification is started by suppressing the temperature distribution in the stacking direction during normal operation without separately providing heat insulation or protection material on the outer periphery of the separator The thermal efficiency in the temperature raising process at the time can be increased.

  According to a second aspect of the present invention, in the fuel cell humidifier according to the first aspect, the humidified fluid manifold and the humidified fluid manifold are formed only in the frame body, and this structure The heat insulation can be enhanced by forming the manifold of the gas that does not require introduction of the flow path only with the frame body, such as the humidifying fluid manifold of the humidifying separator and the humidifying fluid manifold of the humidifying separator.

  According to a third aspect of the present invention, in the fuel cell humidifier according to the first or second aspect, the protrusion formed on the inner and outer periphery of the manifold of the frame body has a protrusion protruding in a direction perpendicular to the stacking direction. And having contact with the inner and outer circumferences of the manifold of the separator and the tip of the protrusion, and a gap is formed between the separator and this configuration forms a gap with the separator. , Can improve the heat insulation.

  According to a fourth aspect of the present invention, in the fuel cell humidifier according to any one of the first to third aspects, at least one of the plurality of protrusions formed on the inner and outer circumferences of the manifold of the frame body is in the stacking direction. One end has a convex shape, the other end has a concave shape, and the concave and convex portions are fitted when single humidifiers are stacked. With this configuration, the concave and convex portions are fitted when single humidifiers are stacked. Thereby, heat insulation can be improved.

  According to a fifth aspect of the present invention, in the fuel cell humidifier according to any one of the first to third aspects, at least one of the plurality of protrusions formed on the inner and outer periphery of the manifold of the frame body is in the stacking direction. It has a taper surface on one inner circumference and the other outer circumference, and is characterized in that both are joined when laminating single humidifiers. By joining, heat insulation can be improved.

  A sixth aspect of the present invention is the fuel cell humidifier according to any one of the first to third aspects, wherein at least one of the plurality of protrusions formed on the inner and outer periphery of the manifold of the frame body is in the stacking direction. A sealing material is integrally formed at one end, and is sealed when stacking single humidifiers. With this configuration, the single humidifier is sealed by a sealing material when stacking. Therefore, heat insulation can be improved.

  According to the humidifier for a polymer electrolyte fuel cell of the present invention, it is possible to suppress the temperature distribution in the stacking direction that is likely to occur during normal operation, shorten the temperature increase time at the start of humidification, and increase the thermal efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The single humidifier in this embodiment is implemented with a configuration as shown in FIG.

(Embodiment 1)
FIG. 1 is an exploded perspective view of a water vapor permeable membrane integrated seal, a humidifying separator, and a humidifying separator as viewed from the humidifying side according to Embodiment 1 of the present invention. In this example, insert molding is performed so that a resin frame 3 having a length of 220 mm and a width of 220 mm is formed around the water vapor permeable membrane 2 having a length of 150 mm and a width of 150 mm.

  The thermoplastic resin constituting the frame 3 is chemically clean and stable at a temperature equal to or lower than the operating temperature of the polymer electrolyte fuel cell humidifier, and has an appropriate elastic modulus and a relatively high deflection temperature.

  Specifically, from the viewpoint of chemical stability, the frame 3 is preferably made of a crystalline resin rather than an amorphous resin, and among them, a material having high mechanical strength and high heat resistance is preferred. For example, a so-called super engineering plastic grade is suitable, and examples include polyphenylene sulfide (PPS), polyether ether ketone (PEEK), crystalline polymer (LCP), and polyether nitrile (PEN). These are suitable materials having a compression modulus of several thousand to several tens of thousands of MPa and a bending load temperature of 150 ° C. or more. Moreover, even if it is a resin material that is widely used, for example, polypropylene (GFPP) filled with a glass filler has an elastic modulus several times that of unfilled polypropylene (compression elastic modulus 1000 to 1500 MPa), Moreover, it has a deflection load temperature close to 150 ° C., and can be suitably used. In the present embodiment, glass filler-added polypropylene (R350G manufactured by Idemitsu Petrochemical Co., Ltd.), which is a thermoplastic resin, is used.

  The frame 3 is formed with a seal portion 4 by molding two colors of thermoplastic resin or thermoplastic elastomer. This thermoplastic resin or thermoplastic elastomer is chemically stable under the operating conditions of the humidifier, and has hot water resistance such as not causing hydrolysis.

  For example, the compression elastic modulus as a gasket is preferably 200 MPa or less. Suitable materials are polyethylene, polypropylene, polybutylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyacrylamide, polyamide, polycarbonate, polyacetal, polyurethane, silicone, fluororesin, polybutylene terephthalate, polyethylene terephthalate, syndiotactic -It can be selected from the group consisting of polystyrene, polyphenylene sulfide, polyether ether ketone, polysulfone, polyether sulfone, polyarylate, polyamide imide, polyether imide, and thermoplastic polyimide. As a result, it is possible to ensure good sealing performance at the fastening load of the humidifier. In this embodiment, Santoprene 8201-60 (manufactured by Advanced Elasotomer System), which is a polyolefin-based thermoplastic elastomer, is used.

  This seal portion 4 is not provided in the portion 6 that connects the water vapor permeable membrane 2 and the manifold 5 that supplies and discharges the humidified gas to the humidifying side of the water vapor permeable membrane 2, so that the gas does not leak to other portions. 7 and 8 and the water vapor permeable membrane 2 are formed. The humidification side manifold 8 and the humidification side manifold 7 are formed with a seal portion 4 so as to surround the manifolds 7 and 8 so as not to leak outside.

  When forming the single humidifier by integrating the water vapor permeable membrane integrated seal 1, the humidified side separator 11 and the humidified side separator 12, the protruding portion 9 between the inner periphery and the outer periphery of each manifold 5, 7, 8 in the frame 3. Covers the outer periphery of the spectacle-shaped manifold 10 connected to the humidifying separator 12 only at the channel introduction part, and the inside of the manifold 8 of the frame 3 and the channel introduction part 10a of the manifold 10 of the humidifying separator 12 The circumferential introduction flow path 5a is communicated. At this time, the humidified fluid manifolds 5 and 8 and the humidified fluid manifold 7 are formed only on the frame 3.

(Embodiment 2)
FIG. 2 is a partial detailed cross-sectional view of the single humidifier after assembly in Embodiment 2 of the present invention.

  In FIG. 2, protrusions 9 on the inner periphery and outer periphery of the manifold 8 of the frame 3 cover the outer periphery of the glasses-like manifold 10 of the humidifying separator 12, and are orthogonal to the stacking direction from the protrusions 9 of the frame 3. A wedge-shaped protrusion 9 a protruding in the direction is in contact with the outer peripheral portion of the glasses-like manifold 10. Thereby, heat insulation can be improved.

(Embodiment 3)
FIG. 3 is a partial detailed cross-sectional view of the single humidifier after assembly according to Embodiment 3 of the present invention.

  In FIG. 3, protrusions 9 on the inner periphery and outer periphery of the manifold 8 of the frame 3 cover the outer periphery of the glasses-like manifold 10 of the humidifying separator 12, and the outer periphery of the glasses-like manifold 10 of the humidifying separator 12. A wedge-shaped protrusion 10b protruding in a direction perpendicular to the stacking direction is in contact with the protruding portion 9. Thereby, heat insulation can be improved.

(Embodiment 4)
FIG. 4 is a partial detailed cross-sectional view of a single humidifier group in which single humidifiers after assembly according to Embodiment 4 of the present invention are stacked.

  In FIG. 4, a convex shape 9b is formed at one end in the stacking direction on the inner or outer periphery of the protrusion 9 in the periphery of the manifold 8 of each frame 3 and on the outer periphery protrusion 3a of the frame 3. A concave shape 9c is formed in the base plate so that the convex shape 9b and the concave shape 9c are fitted when the single humidifier is stacked. Thereby, heat insulation can be improved.

(Embodiment 5)
FIG. 5 is a partial detailed cross-sectional view of a single humidifier group in which single humidifiers after assembly according to Embodiment 5 of the present invention are stacked.

  In FIG. 5, taper surfaces corresponding to one inner periphery 9 d and the other outer periphery 9 e in the stacking direction are formed on the inner periphery or outer periphery of the protrusion 9 in the periphery of the manifold 8 of each frame 3, respectively. When the humidifiers are stacked, they are joined together. Thereby, heat insulation can be improved.

(Embodiment 6)
FIG. 6 is a partial detailed sectional view of a single humidifier group in which single humidifiers after assembly according to Embodiment 6 of the present invention are stacked.

  In FIG. 6, a seal portion 9f is integrally formed with the frame body 3 at one end in the stacking direction on the inner periphery or outer periphery of the protruding portion 9 in the periphery of the manifold 8 of the frame body 3, and a single humidifier is stacked. When doing so, the single humidifiers are hermetically sealed by the seal portion 9f. Thereby, heat insulation can be improved.

(Embodiment 7)
FIG. 7 is a perspective view showing a cross-section of a part of the water vapor permeable membrane integrated seal according to Embodiment 7 of the present invention.

  In FIG. 7, the protrusions 9 on the periphery of the manifold 8 of the frame body 3 are connected to the outer peripheral projections 3a of the frame body 3 by ribs 3b, and a gap 3c is formed between the ribs 3b. Yes. Thereby, heat insulation can be improved.

  As described above, in some conventional fuel cell humidifiers, in order to suppress the temperature distribution in the stacking direction that is likely to occur during normal operation, there is one in which a heat insulating material is disposed on at least a part of the inner periphery of the manifold. . According to this method, there is an effect in suppressing the temperature rise of the humidified fluid and the humidified fluid, but there is no effect in suppressing heat dissipation from the outer periphery of the separator to the outside. Therefore, in order to increase the thermal efficiency at the start of operation, it is necessary to separately provide a heat insulating material outside the separator, which may lead to an increase in manufacturing cost and an increase in the installation space of the humidifier.

  However, according to this embodiment of the above-described configuration, the protrusions of the inner periphery and the outer periphery of the manifold of the frame body cover the manifold portion of the glasses-shaped separator that is connected to the separator humidification portion only at the flow path introduction portion, By connecting the flow passage introduction part of the manifold of the separator and the introduction flow path of the inner periphery of the frame body, it is possible to stack the layers during normal operation without separately providing a heat insulating material or a protective material on the outer periphery of the separator. The temperature distribution in the direction can be suppressed, and the thermal efficiency in the temperature raising process at the start of humidification can be increased.

  Further, according to the embodiment, a gap is formed between the separator and the frame body, the single humidifiers are fitted with irregularities when the single humidifiers are stacked, joined with a tapered surface, or sealed with a seal. Or by forming the interval with ribs, the heat insulation can be further enhanced.

  The present invention is applied to a fuel cell using a solid polymer electrolyte used for a portable power source, a power source for an electric vehicle, a domestic cogeneration system, and the like.

1 is an exploded perspective view of a water vapor permeable membrane integrated seal, a humidifying separator, and a humidifying separator as viewed from the humidifying side in Embodiment 1 of the present invention. Partial detail sectional drawing of the single humidifier after the assembly in Embodiment 2 of the present invention Partial detail sectional drawing of the single humidifier after the assembly in Embodiment 3 of the present invention Partial detail sectional drawing of the single humidifier group which laminated | stacked the single humidifier after the assembly of Embodiment 4 of this invention Partial detail sectional drawing of the single humidifier group which laminated | stacked the single humidifier after the assembly of Embodiment 5 of this invention Partial detail sectional drawing of the single humidifier group which laminated | stacked the single humidifier after the assembly of Embodiment 6 of this invention FIG. 7 is a perspective view showing a cross section of a part of the water vapor permeable membrane integrated seal according to Embodiment 7 of the present invention. Exploded perspective view of a conventional fuel cell humidifier

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water vapor permeable membrane integrated seal 2 Water vapor permeable membrane 3 Frame 3b Rib 3c Gap 4 Seal part 5, 7, 8, 10 Manifold 5a Introduction flow path 9 Protrusion part 9a, 10b Wedge type protrusion 9b Convex shape 9c Concave shape 9d Tapered surface Inner circumference 9e formed with an outer circumference 9f formed with a taper surface Seal portion 10a Flow path introducing portion 11 Humidified side separator 12 Humidified side separator

Claims (6)

Used in polymer electrolyte fuel cells that generate power using a fuel fluid and an oxidant fluid, and in order to humidify at least one of the fuel fluid or the oxidant fluid, a water vapor permeable membrane and a sealing material are integrally formed. A plurality of single humidifiers comprising a pair of separators having a flow path for supplying and discharging a humidified fluid on one side and a flow path for supplying and discharging a humidified fluid on the other side. A fuel cell humidifier comprising:
The frame has a protrusion on the inner and outer periphery of the manifold, and the protrusion covers the separator manifold connected to the separator humidification section at the flow path introduction section, and the flow path introduction section of the separator manifold. The fuel cell humidifier is characterized in that a flow path introduction portion formed on the inner periphery of the manifold of the frame body communicates with the humidifier.   2. The fuel cell humidifier according to claim 1, wherein the humidifying fluid manifold and the humidifying fluid manifold are formed only on the frame.   Protrusions formed on the inner and outer circumferences of the manifold of the frame body have projections projecting in a direction perpendicular to the stacking direction, and are in contact with the inner and outer circumferences of the manifold of the separator and the tips of the projections. A fuel cell humidifier according to claim 1, wherein a gap is formed between the two.   At least one of the plurality of protrusions formed on the inner and outer peripheries of the manifold of the frame body has a convex shape at one end in the stacking direction and a concave shape at the other end, and the single humidifier stack The humidifier for a fuel cell according to any one of claims 1 to 3, wherein irregularities are sometimes fitted.   At least one of the plurality of protrusions formed on the inner and outer periphery of the manifold of the frame body has a tapered surface on one inner periphery and the other outer periphery in the stacking direction, and when stacking the single humidifiers The fuel cell humidifier according to any one of claims 1 to 3, wherein the two are joined to each other.   At least one of the plurality of projecting portions formed on the inner and outer periphery of the manifold of the frame body is integrally formed with a sealing material at one end in the stacking direction, and is sealed when the single humidifiers are stacked. The fuel cell humidifier according to claim 1, wherein the humidifier is a fuel cell humidifier.

Images