JP3556570B2 - Fluid flow plate - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention can be used for an electrochemical device that performs power generation, dehumidification, gas concentration measurement, and the like using an electrochemical reaction.Fluid flow plateIt is about.
[0002]
[Prior art]
An electrochemical device is a device in which a basic reaction for generating power or purifying a gas is performed by utilizing an electrochemical reaction. A fuel cell, which is an example of this device, supplies chemical to one of the electrodes in contact with both sides of the electrolyte body and a oxidant to the other, and electrochemically reacts the oxidation of the fuel in the cell to generate chemical energy. It directly converts the energy into electric energy. For example, in a polymer electrolyte fuel cell, it refers to a solid polymer membrane as an electrolyte and a gas diffusion electrode, or an integrated product thereof.
[0003]
FIG. 25 is a cross-sectional view showing a typical proton conductive solid polymer electrolyte fuel cell. In the figure, 1 is a solid polymer electrolyte membrane, 2 is an anode electrode, 3 is a cathode electrode, 4 and 5 are conductive fluid flow plates, 6 is an anode gas flow path, and 7 is a cathode gas flow path. As the polymer electrolyte membrane 1, a perfluorosulfonic acid membrane has recently been used as a high-performance membrane. The electrodes 2 and 3 are formed by kneading a conductive powder with a catalyst powder and a binder as disclosed in JP-A-3-25856.
[0004]
Next, the operation will be described. When hydrogen gas is supplied to the anode electrode 2 and oxygen is supplied to the cathode electrode 3 and current is taken out from the anode electrode 2 and the cathode electrode 3 through an external circuit, the following reaction occurs.
Anode reaction
H₂→ 2H⁺+ 2e⁻              ‥‥‥‥‥‥‥‥‥‥‥‥‥ (1)
Cathodic reaction
2H⁺+ 2e⁻+1/20₂→ H₂O ‥‥‥‥‥‥‥‥‥‥‥‥ (2)
At this time, hydrogen becomes a proton on the anode electrode 2, moves with the water through the electrolyte membrane 1 to the cathode electrode 3, and reacts with oxygen on the cathode electrode 3 to produce water. Therefore, when this reaction occurs, gas and liquid water flow in and out of the pores of the electrode, and electrons flow in the base material of the electrode. The current flowing at this time is sometimes 1 A / cm²In order to improve the battery characteristics, in order to increase the area of the interface between the electrolyte membrane 1 and the electrode where the reaction actually takes place, for example, as disclosed in JP-A-3-1677752 A method has been proposed in which an uneven surface is pressed against the surface, or the surface of the film is ground with an abrasive as disclosed in Japanese Patent Publication No. 2-4978.
Further, in order to fix the catalyst and the electrode on the surface of the electrolyte membrane, Japanese Patent Publication No. 2-4978 and Japanese Patent Application Laid-Open No. 3-208262 propose a method of hot pressing or hot pressing in a solvent. . Further, Japanese Patent Application Laid-Open No. 4-329264 has been proposed.
[0005]
In addition, in order to continue the electrochemical reaction, it is necessary to supply and discharge gas and water and to extract current. Therefore, as a fluid flow field plate for extracting a current from a fuel cell and for efficiently flowing gas and water, for example, a fluid flow field plate disclosed in Japanese Patent Application Laid-Open No. Hei 3-205763 has been proposed. FIG. 26 is a plan view of the fluid flow plate 5. In the figure, 10 is a main surface, 11 is an electrode supporting portion, 12 is a fluid supply port, 13 is a fluid inlet, 14 is a fluid outlet, and 15 is a fluid outlet. When gas is supplied from the fluid supply port 12, the supplied gas enters the cathode electrode 13 through the fluid inlet 13 because the space is surrounded by the main surface 10 and the electrolyte body 1. Here, the main flow of the gas is guided by the cathode electrode 3 and the electrode support 11 and flows along the cathode gas flow path 7, and the gas not consumed and generated gas in each part of the cathode electrode 3 passes through the fluid outlet 14. It is discharged from the fluid discharge port 15. Here, oxygen is supplied from the gas fluid supply port 12 to flow through the cathode gas flow path 7, and simultaneously, hydrogen containing water also flows through the anode gas flow path 6 on the anode side, and the fluid flow plates 4 and 5 are electrically driven. If the connection is made externally, the reaction of the formula (2) occurs on the cathode electrode 3, and the unreacted gas and water are discharged from the fluid outlet 15 through the fluid outlet 14. On the other hand, unreacted gas is similarly discharged from the anode electrode 2. In this case, electrons flow from the anode electrode 2 through the fluid flow plate 4 via the electrode support portion. In a typical polymer electrolyte fuel cell as described above, 1 A / cm per electrode area²The above high current can be taken out. For example, the electrode area is 100 cm.²In a fuel cell of the order, the current flowing through a single cell is actually 100 A or more. In order to reduce the resistance loss when a current flows, it is fundamental to increase the cross-sectional area and shorten the length. The thickness of the unit cell of the fuel cell stack is 1 cm or less, and if an efficient current path with little resistance loss is taken, it passes through a fluid flow plate made of a conductor.
[0006]
[Problems to be solved by the invention]
Since the conventional solid polymer electrolyte fuel cell is configured as described above,,productIn the stratified structure, the distribution of gas to each cell and the uniform distribution of gas to each flow path inside the cell were necessary for highly efficient operation. There are problems such as a narrow path and difficulty in achieving uniform gas distribution.
[0007]
The present invention has been made to solve the above problems, and can control the flow rate of a fluid easily and at low cost.Fluid flow plateThe purpose is to get.
[0011]
[Means for Solving the Problems]
According to this inventionFluid flow plateIsA fluid control member having a plurality of flow passages arranged in parallel and using a polymer water-absorbing material that swells by absorbing moisture contained in the fluid flowing through each flow passage at the outlet side of each flow passage.Is provided.
Fluid flow plate according to the present inventionIsIt has a plurality of flow passages arranged in parallel, and at the outlet side of each flow passage, when hydrogen contained in the fluid flowing through each flow passage has a predetermined concentration or more, it absorbs the hydrogen and swells. A fluid control member using a hydrogen storage alloy that releases and contracts the hydrogen when the concentration is less than a predetermined concentration is provided.Things.
[0019]
(Action)
In this inventionFluid flow plateIsSince the amount of water absorption of the polymer absorbent changes due to the change in the amount of water in the fluid, and the degree of swelling changes, the polymer absorbent material is placed at the outlet side of each flow path in a plurality of flow paths arranged in parallel. The flow rate of the fluid flowing out from the outlet side of each flow path portion is controlled by providing the fluid control member using.
In this inventionFluid flow plateIsSince the hydrogen storage alloy absorbs hydrogen when the hydrogen in the fluid is at or above a predetermined concentration and swells and releases and contracts when the hydrogen in the fluid is at or below the predetermined concentration, the hydrogen storage alloy in a plurality of flow passages arranged in parallel By providing a fluid control member using a hydrogen storage alloy on the outlet side of each flow path section, the flow rate of the fluid flowing out from the outlet side of each flow path section is controlled.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
Reference example1.
Hereinafter, Embodiment 1 of the present invention will be described.Figure 1 is a bookReference exampleFIG. 2 is a cross-sectional view showing the configuration of the electrochemical device of Example 1, wherein 21 is a polymer electrolyte membrane, and 2 and 3 are electrodes.
The polymer electrolyte membrane 21 is a square membrane having a thickness of 60 μm and a side of 95 mm, and is formed by swelling a polymer electrolyte immersed in a 60% aqueous solution of isopropanol (IPA) and contracting the polymer electrolyte in the thickness direction.
[0025]
Next, a method for manufacturing an electrochemical device will be described.
Figure 2 is a bookReference exampleFIG. 2 is a conceptual plan view in one step in manufacturing a thin film having a thin film, in which 22 is a polymer electrolyte membrane, and 23 is a fixing frame. FIG. 3 shows the change in length (length and width) when a Nafion 115 membrane commercially available from DuPont as a perfluorosulfonic acid membrane was swollen in an isopropanol aqueous solution at room temperature. In an aqueous solution having a concentration of 60 wt% of isopropanol (hereinafter abbreviated as IPA), the area is expanded as much as 1.4 times and 1.6 times as long, so the area is as large as 2.24 times. Return to the original size. BookReference exampleIn this example, Nafion 115 having a thickness of 135 μm was cut into a rectangle of 60 mm × 70 mm and immersed in a 60% aqueous solution of IPA. At this time, the film 22 spread to a square of about 100 × 100 mm. This was sandwiched between two 95 mm-square polycarbonate frames 23, and the film protruding with the clip was not shifted. When this is dried in air at 60 ° C., the film inside the 95 mm square must be shrunk with the 95 mm square even when shrinking by drying, so the film thickness is reduced to maintain the volume when dried. Was. After drying, the portion protruding from the frame 23 was cut off, and the film 22 was removed from the frame 23. As a result, a square film 21 having a thickness of 95 μm and a thickness of 60 μm was obtained. As a result, a thin film 21 having no distortion can be easily obtained, and at the same time, the amount of the film used to manufacture a device having the same area can be reduced to half that of the conventional device. Further, as shown in FIG. 3, since the spread of the film changes with the concentration of the IPA aqueous solution, in the case of Nafion 115, a film having an arbitrary thickness of 60 μm to 135 μm can be obtained by adjusting the composition of the immersion liquid. all right. When a film thinned by this method is immersed in a liquid, it swells again, so that a thinner film can be obtained. In addition, even if the same perfluorosulfonic acid film has the same molecular structure, there is a great difference in the way of elongation. Therefore, if the perfluorosulfonic acid film has a different specification, the manufacturing conditions need to be changed. .
[0026]
FIG. 4 shows an X-ray diffraction pattern of the dried Nafion 115, showing the presence of clusters such as A and B. Also, in the X-ray diffraction pattern when immersed in IPA or water, it can be seen that the cluster diameters of A and B are large (not shown). However, when this film was immersed in a mixed solution of IPA and water, the appearance of new clusters as shown in FIG. 5C was observed. In parallel with this, when the resistance of the film during swelling was measured, it was found that the resistance greatly changed depending on the IPA concentration as shown in FIG. In particular, when the IPA concentration is about 50%, the minimum resistance is shown even though the thickness of the film is the maximum, indicating that the volume resistivity is the minimum. This is considered to be due to the fact that a new path of ion migration was created by the appearance of a new cluster. When the membrane is used in a state in which an IPA aqueous solution or other clusters corresponding to C (2θ = 27 °) appear, for example, in a swollen state, it is possible to perform an operation with small voltage loss.
[0027]
Reference example2.
Hereinafter, the present inventionReference Example 2Will be described. FIG. 7 shows the position of the needle tip when the needle is pushed into the Nafion 115 and the pressure is changed to cause the needle to penetrate, and the vertical axis is normalized by the thickness of the dried film. B is a result of using a dried film, and A is a result of using a film swollen in a 50% aqueous solution of IPA. Thus, it was found that the swollen film easily deformed according to the pressure. FIG. 8 shows a state in which a press for forming irregularities on the surface of the film is performed based on the test results. In the figure, 27 and 28 are molds having irregularities, and 29 and 30 are press plates. FIG. 9 shows the amount of change in thickness when drying is performed with the mold and the film together after applying surface pressure in this state. 50kg / cm if you want to make irregularities on both sides of the film thickness²It can be seen that when a certain surface pressure is applied, unevenness having a thickness substantially corresponding to the film thickness can be obtained. FIG. 10 shows a stereomicrograph of the unevenness formed on the film surface by this.
[0028]
Reference example3.
Hereinafter, the present inventionReference example3 will be described with reference to FIG. In FIG. 11, reference numeral 31 denotes irregularities formed on the film surface. When an IPA aqueous solution is applied to a part of the electrolyte membrane, the portion permeated with the IPA aqueous solution swells as shown in the first embodiment, but unlike the case where the IPA aqueous solution is immersed in the liquid, the membrane does not extend uniformly and is distorted In order to prevent this, the film 22 is sandwiched between the fixing frame 23 having an opened window for applying the catalyst. Next, adjustment of the coating liquid is performed. In this embodiment, since the catalyst is contained in the liquid, there is a danger that oxygen in the air and IPA may react during drying, and the IPA concentration is 30% or less. Was suppressed. Of course, if the operation can be realized in a vacuum or an inert gas atmosphere, the IPA concentration can be increased. In addition, the catalyst alone can be attached to the membrane by this method alone. However, in order to increase the adhesion between the catalyst particles and the electrolyte membrane 22, a solution prepared by dissolving the polymer electrolyte in a 90% aqueous IPA solution by an autoclave is added. The solution contained 2% of a polymer electrolyte as a solute. First, water was added to platinum black and stirred, then an IPA solution containing a polymer electrolyte as a solute was added and stirred, and ultrasonic vibration was applied for 10 minutes to disperse the platinum particles. This was applied to the film 22 sandwiched between frames 23 with a brush. When the coating was performed, the portion with the liquid swelled and was distorted, but when dried at 50 ° C. in vacuum, the film returned to the original straight film. By rubbing the film with a brush when applying the film, fine grooves are formed on the film surface, and the distribution of the liquid to be applied is distributed, and fine irregularities 31 are formed on the film surface during drying We were able to.
[0029]
Reference example4.
Hereinafter, the present inventionReference example4 will be described.Reference exampleAs shown in FIG. 2, when the molds 27 and 28 having irregularities are pressed against the swollen film 22, the film 22 is deformed and irregularities corresponding to the irregularities of the molds 27 and 28 are formed on the surface of the film 22. The concave and convex shapes of the pressing dies 27 and 28 are complicated. For example, in a state where the fibers are entangled, the film 22 and the dies 27 and 28 cannot be separated from each other when the surface pressure exceeds a certain level. Therefore, as shown in FIG. 12, carbon papers 41 and 42 used for the electrode substrate are inserted in place of the molds 27 and 28, and 100 kg / cm²When a certain surface pressure is applied, the carbon papers 41 and 42 and the electrolyte membrane 22 remain in close contact with each other to form an integrated body even when the surface pressure is released. When the electrode has a catalyst, the content of the organic substance in the liquid for swelling needs to be 30% or less. However, when the atmosphere can be made with an inert gas until the drying step is completed, It is also possible to increase the organic content.
[0030]
Reference example5.
Hereinafter, the present inventionReference example5 will be described. Figure 13 is a bookReference exampleFIG. 14 is a cross-sectional view of an electrochemical device using an electrode having a difference in the dimensions of FIG.
Here, 45 and 46 are spacers, and 47 and 48 are gaps between the electrode 2-spacer 45 and the electrode 3-spacer 46. Nafion 115 is applied to the electrolyte membrane 21.Reference exampleThe electrode 2 was cut into a 10 cm square, and the electrode 3 was cut into a 10.5 cm square. Aramid paper having a thickness of 250 μm and a thickness of 50 μm thinner than the electrode was used as the spacer. The spacer 45 has an outer diameter of 15 cm square and a hole of 10.1 cm square inside, and the spacer 46 has an outer diameter of 15 cm square and a hole of 10.6 cm square inside. These are superposed on each other as shown in FIGS. 13 and 14 at 190 ° C. and 50 kg / cm.²Hot pressing was performed at the surface pressure of When this integrated product was released from the pressing device and the thickness was measured, the electrode bit into the membrane by about 60 μm, and the integrated product had a uniform thickness of 550 μm. At this time, the gaps 47 and 48 are about 0.5 mm, and the electrode 3 or the spacer 45 exists on the side facing the film of the gap. And kept a straight plane. Further, the integrated product was left for several days in air in which the humidity changes from 20% to 60%, but no warping or distortion occurred.
Further, the electrochemical device was used for a solid polymer electrolyte fuel cell, and after operating once, no change was observed in the shape even when disassembled, and the device could be assembled and used.
[0031]
The bookReference exampleIn the above, aramid paper was used for the spacer, but other materials such as PTFE, PFA sheet, and polyimide film can be used as long as they have heat resistance that can withstand the conditions during production and operation. However, since the aramid paper or the polyimide does not soften even at the temperature of the hot press, the gap can be kept constant. However, since the sheet of PTFE or PFA softens at the temperature of the hot press, the gaps 47 and 48 may be widened. . However, once integrated, the dimensional stability is high, and the positions and sizes of the holes do not change even when the temperature or humidity changes during operation.
[0032]
Reference example6.
Hereinafter, the present inventionReference example6 will be described. FIG. 15 shows a cross section in the traveling direction of the flow path 51 in which the effective cross-sectional area changes according to the temperature. Here, a bimetal that bends along the flow path wall 53 at 70 ° C. or lower and almost 90 ° at 80 ° C. was used. The channel wall 53 carries a platinum-based catalyst.
[0033]
Here, a mixed gas (fluid) 54 of the fuel exhaust gas and the air is caused to flow through the flow path 51 to burn excess fuel. When the temperature of the mixed gas 54 is 70 ° C., the regulating plate 52 is along the flow path wall 53, the flow resistance is small, and the combustion is performed to the maximum. When the temperature rises and exceeds 70 ° C., the adjustment plate 52 warps, the effective area of the flow path 51 decreases, and the flow rate of the mixed gas 54 decreases. Due to the decrease in the flow rate, the calorific value due to combustion decreases, and the temperature starts to decrease. Then, the resistance of the adjusting plate 52 also decreases along the flow path wall 53, and the flow rate increases. As described above, the cross-sectional area of the flow path 51 can be automatically adjusted such that the temperature of the mixed gas 54 becomes close to 70 ° C. Also bookReference exampleThen, the adjustment plate 52 was attached by spot welding technology. As long as the material of the adjustment plate 52 is deformed depending on the temperature and is not affected by the mixed gas 54, for example, a material using a shape memory alloy or a synthetic fiber can be used. It is possible to attach by the method of. Further, the temperature at which the substantial deformation is performed may be arbitrarily set depending on the operating conditions.
[0034]
WhereReference exampleOtherReference exampleWill be described. Figure 16 is a bookReference exampleA material that swells and shrinks due to the composition of the fluid is supported on the flow channel wall, and the vertical cross section of the flow channel whose effective cross-sectional area changes according to the fluid composition is shown. 55 is a polymer material that swells when containing water (Polymer water-absorbing material) 56 is a material constituting a flow path, which is a partially enlarged filter using a metal foam material having a hole diameter of 0.2 mm.
[0035]
Here, when gasoline flows through the filter 56, the polymer material 55 is contracted when gasoline alone is used, so that gasoline can pass through the filter 56. However, if water is mixed in the gasoline, the polymer material 55 swells, and the flow path 57 of the filter 56 is blocked and does not flow, so that it is possible to prevent gasoline mixed with water from entering.
[0036]
Embodiment1.
Hereinafter, embodiments of the present invention.1Will be described. FIG. 17 shows the present embodiment.ofFIG. 4 is a plan view of a fluid flow channel plate having a flow channel carrying a polymer absorbent in an outlet flow channel. Fluid plate 4 is a carbon plate formed by digging a groove by machining, 60 is a main surface, 62 is a fluid supply port, 63 is a total fluid inlet, 6 is a parallel flow path, 64 is a total fluid outlet, and 65 is a total fluid outlet. Reference numeral 61 denotes a fluid outlet, and a support portion 61 of the device to which the fluid reacts. 71 is a polymer water absorbing material,Reference exampleThe solution obtained by dissolving the perfluorosulfonic acid used in 1 in isopropanol was applied to a position 1 cm from the outlet of each flow path 6, dried, and held in air at 190 ° C. for 2 minutes for fixing. FIG. 18 is a conceptual sectional view of the flow path 6.
[0037]
When a fluid containing water flows from the fluid supply port 62, the fluid branches and flows into the parallel flow paths 6 a to 6 m through the fluid total inlet 63, and flows out of the fluid discharge port 65 via the fluid total outlet 64. To go. At this time, if a reaction that consumes moisture is being performed by the device supported by the fluid support unit 6, the amount of moisture of the fluid at the total fluid outlet 65 is smaller than the moisture in the total fluid inlet 63. On the other hand, when looking at each of the channels 6a to 6m, the amount of water in the outlet fluid of each channel differs depending on the in-plane distribution of the reaction in the device and the flow rate of the fluid flowing through each channel. If the reaction amount in the flow channel 6i is smaller than the fluid flow rate, the water content at the outlet of the flow channel 6i increases. Then, the water-absorbing material 71 in the flow path 6i swells from the left state in FIG. 18 to the right, the cross-sectional area of the flow path decreases, the resistance becomes larger than the other flow paths, and the amount of fluid flowing through the flow path 6i Decrease and flow to other low resistance channels. Since this is performed in each flow path, the flow rate distribution is automatically adjusted so that the amount of water at the outlet of each flow path 6a to 6m is substantially constant.
[0038]
Further, in this embodiment, only the flow rate distribution in one fluidized plate is described. For example, a plurality of such flow path plates and reaction devices are stacked to adjust the flow rate of the fluid flowing through each fluidized flow plate. In such a case, it is also possible to use the above-mentioned water absorbing material in the portion of the total fluid outlet 64 of each fluidized plate. Further, as the polymer water-absorbing material, another type of material can be used as long as it meets the operating conditions in terms of heat resistance and chemical resistance.
[0039]
Embodiment2.
Hereinafter, embodiments of the present invention.2Will be described. The figure conforms to FIGS. The fluidized plate 4 is formed by digging a groove in SUS316 by machining and using a hydrogen storage alloy instead of the polymer water absorbing material 71. This hydrogen storage alloy was composed of a palladium / silver alloy, and a SUS mesh having a pore diameter of 10 μm was provided at the outlet of the flow channel and held.
[0040]
When a gas containing hydrogen flows from the fluid supply port 62, the gas branches and flows into the parallel flow paths 6 a to 6 m through the total fluid inlet 63 and flows from the fluid discharge port 65 via the total fluid outlet 64. to go out. At this time, when a reaction consuming hydrogen is performed by the device supported by the fluid support portion 61, the hydrogen concentration in the gas at the total fluid outlet 65 becomes lower than the hydrogen concentration in the total fluid inlet 63. On the other hand, when looking at each of the channels 6a to 6m, the hydrogen concentration of the outlet gas of each channel varies depending on the in-plane distribution of the reaction in the device and the gas flow rate flowing through each channel. If the hydrogen gas consumption in the flow channel 6i is smaller than the gas flow rate, the hydrogen concentration at the outlet of the flow channel 6i increases.
Then, the hydrogen storage alloy in the flow path 6i has a swelling amount of hydrogen storage, the cross-sectional area of the flow path is reduced, the resistance is larger than the other flow paths, the gas flow rate flowing through the flow path 6i is reduced, and the other resistance is reduced. Flow through a low flow path. Since this is performed in each flow path, the flow rate distribution is automatically adjusted so that the hydrogen concentration at the outlet of each flow path becomes substantially constant.
Also, in this embodiment, a palladium alloy is used as the hydrogen storage alloy, but a lanthanum / nickel-based alloy or another alloy may be used.
[0041]
Embodiment3.
Hereinafter, the embodiment3Will be described. FIG.Reference example1. Electrochemical device and embodiment1This is a dehumidifier 81 to which the flow path plate is applied. The flow path plate 82 is a molded product of polypropylene, and the outlet side flow path wall has irregularities, on which a polymer water-absorbing agent is carried. The opposing channel plate 83 is also a molded polypropylene product and has a channel cross-sectional area of 1/6 of the channel of the channel plate 82. The anode electrode 2 and the cathode electrode 3 are connected to an external DC power supply.
[0042]
Next, the operation will be described.
When a DC voltage is applied to both electrodes in the air, the dehumidifier 81 loses electrons in the air on the anode side due to an electrochemical reaction and becomes hydrogen ions on the anode side, and moves through the electrolyte membrane to the cathode side.
2H₂O → 4H⁺+ O₂+ 4e⁻    ‥‥‥‥‥‥‥‥‥‥‥‥‥ (3)
The hydrogen ions obtain electrons on the cathode and are reduced to hydrogen, but react with oxygen in the air to become water.
4H⁺+ O₂+ 4e⁻→ 2H₂O ‥‥‥‥‥‥‥‥‥‥‥‥‥ (4)
Eventually, the water on the anode side moves to the cathode side, and lowers the humidity of the space on the anode side.
[0043]
Here, when the air flows through the dehumidifier 8, 97% of the air flows through the flow path 6 due to the difference in pressure loss between the upper and lower flow paths. Then, when the DC power supply is started, the air flowing through the flow path 6 reacts on the anode electrode 2 according to the formula (3), the water in the air is decomposed, and the protons travel in the electrolyte 4 toward the cathode electrode 3. It travels and combines with oxygen in the air flowing through the flow channel 7 by the reaction of the formula (4), and comes out as water. Here, when there is a distribution in the amount of air flowing in the parallel flow paths 6, a difference occurs in the water content of the outlet gas.1As described in the above, the gas is optimally distributed to each gas flow path, and can efficiently dehumidify the air and increase the oxygen concentration.
Further, when carbon monoxide is contained in the air, the carbon monoxide is oxidized and converted into carbon dioxide in preference to the reaction of the formula (3), so that there is also a carbon monoxide removing ability.
It was found that when air was sent into the dehumidifier 81, the relative humidity could be reduced by 40 to 50% as compared with the original case.
[0044]
Embodiment4.
Hereinafter, the embodiment4Will be described. FIG. 20 is a gas flow diagram of the air purifier 90 of this embodiment.3, 91 is a fan, 92 is an electrostatic filter, 93 is a water tank, and 94 is an air conditioner. For the electrostatic filter, Syntex EL / EB-20N manufactured by Mitsui Petrochemical was used.
[0045]
Next, the operation will be described. When a power supply (not shown) is turned on, a fan 91 rotates, and air is removed of airborne particulates such as cigarette smoke and dust by an electrostatic filter 92 and enters the dehumidifier 90. The dehumidifier 90 reduces the humidity in the air, removes carbon monoxide, and discharges the oxygen-enriched air. Since pure water is generated at the counter electrode, the pure water can be stored in the tank 93. When the air purifier 90 is used in, for example, an automobile, the interior of the automobile is humid, and the roadside is rich in carbon monoxide. Further, since dust and smoke are removed from the air introduced into the dehumidifier 81, the electrolyte membrane 21 is less likely to be contaminated, and the life of the dehumidifier 81 can be greatly extended. Further, if the exhaust air from the air purifier 90 is sent to the air conditioner 94, the humidity is so low that there is no dew condensation at the cooling fins. Since the heat transfer resistance can be kept low, the cooling efficiency is increased.
[0046]
Embodiment5.
Hereinafter, the embodiment5Will be described. FIG. 21 shows the aboveReference exampleElectrochemical devices shown in 1, 3 and 5 and embodiments2FIG. 2 is a conceptual cross-sectional view of a fuel cell stack 100 using the flow channel plate on the fuel side. The film 21 is obtained by swelling and thinning Nafion 115 with a 50% aqueous solution of IPA.Reference exampleApply by the method shown in 3,Reference exampleThe assembly was assembled with the dimensional structure shown in Fig. 5 to form an integrated product, and a gas supply / discharge port and a hole for positioning were opened in the separator. Since the assembly and the separator can be easily handled by hand, a rod is set up in the positioning hole of the laminated body end plate (not shown), and each positioning hole is passed through the rod to be integrated with the separator plate. Were alternately stacked to form 10 cells. Finally, place one end plate, and the surface pressure of the battery is 6 kg / cm via a disc spring.²Tightened.
[0047]
Next, the operation will be described. When fuel containing humidified air and hydrogen was flowed from the end plates so as to flow through the flow paths 7 and 6 of each cell, a voltage of about 10 V was generated between the stack end plates. When current was caused to flow through the stack by an external circuit, current flowed through the stack, and the temperature of the stack increased due to the generation of heat. At this time, on the anode electrode 2, hydrogen emits electrons by the reaction of the formula (1), and moves in the film 21 toward the cathode electrode 3. On the other hand, hydrogen ions and oxygen are combined at the cathode electrode 3 to obtain electrons and water is generated by the reaction of the formula (2). When hydrogen gas containing 30% carbon dioxide is used as the fuel, the hydrogen gas concentration at the outlet becomes 32% when the fuel utilization rate is 80%. The hydrogen concentration at the inlet of the parallel flow passages is the same at 70% in all the flow passages, but differs at the outlet when there is a difference between the amount actually reacted and the flow rate of the flowing fuel. When the difference is large, no reaction occurs in a part of the cell surface, and the current is concentrated in a part, thereby deteriorating the characteristics. However, since the hydrogen storage alloy is charged in the fuel-side outlet flow channel of the fuel cell of the present embodiment and can be automatically adjusted so as to keep the outlet hydrogen concentration constant, a minimum amount of fuel is supplied. High performance was able to be achieved only by itself. Further, since the film was very thin, the resistance was reduced to half that of the conventional one, and high characteristics could be maintained even at a high current density. When pure hydrogen is injected into the fuel, the effect of the flow rate control using the hydrogen storage alloy is reduced since the hydrogen concentration hardly changes between the inlet and the outlet. However, in order for the reaction of the formula (7) to proceed, the water on the anode side also moves in the membrane together with the hydrogen ions, so that the water in the fuel gas is consumed. It is possible to optimize the flow distribution by using.
[0048]
Reference Example 7.
Less than,Reference Example 7Will be described. FIG.Reference exampleFIG. 2 is a conceptual cross-sectional view of a hydrogen gas concentration sensor 110 using one thin electrolyte membrane 21. In the figure, reference numeral 2 denotes an electrode that contacts the gas to be measured, and reference numeral 3 denotes an air electrode. As the electrode material, a conventional gas diffusion electrode having a diameter of 5 mm was used. The film was adjusted to a thickness of 80 μm with an IPA concentration of 20%. Reference numerals 111 and 112 denote integral polyethylene molded frames. The frame 111 is provided with a flow path 6 for flowing a gas to be inspected, and the frame 112 is provided with a hole 113 having a diameter of 1 mm and an opening degree of 50% so as to be in contact with the atmosphere. Is formed. A conducting wire for extracting voltage is connected to the electrodes 2 and 3. With the polyethylene molded frames 111 and 112 being opened, the electrodes 2 and 3 and the membrane 21 were placed and sandwiched, whereby an integrated hydrogen gas concentration sensor 110 was produced.
[0049]
Next, the operation will be described.
thisReference exampleWhen a pure gas flows through one of the electrodes and a test gas containing hydrogen is introduced into the other electrode, a potential E corresponding to Nernst equation (5) is generated between the two electrodes. By measuring the voltage, the hydrogen concentration in the gas to be inspected can be known.
E = RT / 2F × 1n (P_H2/ P_R) ‥‥‥‥‥‥‥‥‥‥‥‥ (5)
Where R is the gas constant, F is the Faraday constant, T is the absolute temperature, P_H2Is the partial pressure of hydrogen gas in the test gas, P_RIndicates the pressure of pure hydrogen.
thisReference exampleWhen the fuel exhaust gas flows through the flow path 6 while the sensor 110 is in the air, the hydrogen concentration P of the exhaust gas is set between the electrodes 2-3._H2Generates the voltage of Expression (6).
E = ΔG / 2F + RT / 2F · 1n (0.458P_H2) ‥‥‥‥ (6)
ΔG: Gibbs free energy change in water production
Thus, by measuring this voltage, the hydrogen concentration in the exhaust gas can be measured. At this time, since the gas to be measured is destroyed in principle, it can be returned to the hydrogen recovery device or the like as it is. BookReference exampleIn this example, the thickness of the film was set to 80 μm. However, as a result of an experiment, if the thickness was smaller than this, an accurate voltage was not generated due to gas permeation in some cases. Although the thickness may be larger than that, the cost can be reduced by using a thin film.
[0050]
Reference Example 8.
Less than,Reference Example 8Will be described. FIG.Reference exampleElectroless platinum plating is performed on the film 22 having the two irregularities,Reference exampleAn electrolytic cell 120 using an electrochemical device having the structure of 5 is provided, 21 is an electrolyte membrane, 3 is an anode, and 2 is a cathode. 121 is an anode current collector, 122 is a cathode current collector, 123 is a water supply port, 124 is an oxygen outlet, and 125 is a hydrogen outlet. The base material of the electrodes 2 and 3 was a titanium expanded metal having a thickness of 0.1 mm, the electrode 2 was plated with platinum, and the electrode 3 was plated with iridium. As the electrolyte membrane 21, a Nafion membrane was used as a perfluorosulfonic acid membrane.
[0051]
Next, the operation will be described.
In the electrolytic cell 120, for example, water is supplied to the anode side, and when a DC voltage is applied to both electrodes, the water loses electrons and becomes hydrogen ions and oxygen gas at the anode 3 due to an electrochemical reaction, and oxygen gas is generated as gas. Then, the hydrogen ions move to the cathode 2 side in the electrolyte membrane. On the other hand, at the cathode 2, the hydrogen ions obtain electrons and are generated as hydrogen gas. At this time, since the resistance in the electrochemical reaction is low, oxygen and hydrogen can be efficiently obtained from water.
2H₂O → 4H⁺+ O₂+ 4e⁻‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (7)
4H⁺+ 4e⁻→ 2H₂    ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (8)
Here, when a DC voltage is applied between the electrodes 2 and 3, water is decomposed on the anode 3 by the reaction of the formula (7) to generate oxygen, while hydrogen gas is generated at the cathode 2 according to the formula (8). I do. When a voltage of 2 V is applied between the electrodes 2 and 3, the current density becomes 600 mA / cm²Thus, a current 1.2 times as large as that of the conventional flat film could be passed.
Further, the size of the electrode 2 and the electrode 3 are different, so that the strength of the film is increased, and the film is not damaged even when the water in the tank is drained and dried.
[0052]
Embodiment6.
Hereinafter, the embodiment6Will be described. FIG.Reference exampleTo a film with two irregularitiesReference example3. An electrochemical device having a catalyst supported by the method of 3 and hot-pressed at 150 ° C. with a titanium mesh and an embodiment2FIG. 3 is a cross-sectional view of a hydrogen purifier 130 using the flow channel plate. The lower part of the electrochemical device is the anode 3 and the upper part is the cathode 2. The flow path plate 82 is made of tantalum and has palladium adhered to the flow path 6. The channel plate 83 is made of SUS316L and has the channel 7 formed therein.
[0053]
Next, the operation will be described.
In this hydrogen gas purifying apparatus 130, when a hydrogen gas containing impurities is caused to flow on the anode side and only a voltage is applied, only the hydrogen gas reacts to become hydrogen ions, and moves to the cathode side in the electrolyte membrane.
H₂→ 2H⁺+ 2e⁻  ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (9)
2H⁺+ 2e⁻→ H₂  ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ (10)
On the cathode side, hydrogen ions obtain electrons and are reduced to hydrogen gas. Since only hydrogen ions can move in the electrolyte membrane, pure hydrogen can be obtained on the cathode side.
[0054]
Here, when a hydrogen gas containing carbon dioxide as an impurity is introduced into the gas flow channel 6 and a voltage of 2 V is applied to the flow channel plate 82 with respect to the flow channel plate 83, the reaction of the formula (9) occurs on the anode 3. Only the hydrogen gas becomes a proton, moves the electrolyte membrane 21 toward the cathode 2, returns to the hydrogen gas by the reaction of the formula (10), and is introduced into the flow path 7.
At the outlet side of each of the parallel flow paths 6 of the flow path plate 82, when the amount of the gas to be purified flowing is large or the reaction amount is small, the hydrogen concentration increases, and the adhered palladium swells and the cross-sectional area of the flow path decreases. To another flow path. As a result, the concentration of hydrogen exiting from each flow path becomes substantially constant, and a considerable amount of hydrogen in the gas to be purified can be recovered. Further, since the surface area of the electrolyte membrane was increased, the processing flow rate was significantly increased as compared with the conventional purification apparatus, and the efficiency was improved.
[0058]
【The invention's effect】
As described above, according to the present invention, the fuel cellOr dehumidifierofanodeA fluid control member using a polymer water-absorbing material is provided on the outlet side of each of the plurality of flow passages arranged in parallel on a fluid flow plate for supplying a fluid containing oxygen to the electrodes. Therefore, the flow rate of the fluid flowing out from the outlet side of each flow path portion can be controlled easily and at low cost, and the operation cost can be reduced.
According to the present invention, a fuel cellOr hydrogen purification equipmentA fluid control member using a hydrogen storage alloy is provided on the outlet side of each of the plurality of flow passages arranged in parallel provided on a fluid flow plate for supplying a fluid containing hydrogen to the anode electrode. With such a configuration, the flow rate of the fluid flowing out from the outlet side of each flow path can be controlled easily and at low cost, and there is an effect that the operating cost can be reduced.
[Brief description of the drawings]
FIG. 1 of the present invention.Reference example1 is a sectional view showing an electrochemical device according to Example 1.
FIG. 2 of the present invention.Reference exampleFIG. 2 is a plan view showing the method for manufacturing an electrochemical device according to No. 1;
FIG. 3 is a view showing a relationship between a liquid composition and swelling of a film.
FIG. 4 is a view showing an X-ray diffraction pattern of dried Nafion 115.
FIG. 5 is a view showing an X-ray diffraction pattern of swollen Nafion 115.
FIG. 6 is a diagram showing resistance when a film is swollen.
FIG. 7 of the present invention.Reference Example 2FIG. 7 is a diagram showing the results of a needle penetration test of a membrane by the method shown in FIG.
FIG. 8 of the present invention.Reference exampleFIG. 4 is a diagram showing a method of manufacturing an electrochemical device according to No. 2;
FIG. 9 is a diagram illustrating a relationship between a surface pressure and a thickness change amount.
FIG. 10 of the present invention.Reference exampleFIG. 2 is a micrograph of the film surface of the electrochemical device according to FIG.
FIG. 11 of the present invention.Reference example3 is a sectional view showing an electrochemical device according to FIG.
FIG. 12 of the present invention.Reference exampleFIG. 4 is a cross-sectional view illustrating a method of manufacturing an electrochemical device according to Example 4.
FIG. 13 of the present invention.Reference example5 is a cross-sectional view showing an electrochemical device according to FIG.
FIG. 14 of the present invention.Reference example5 is a plan view showing an electrochemical device according to FIG.
FIG. 15 of the present invention.Reference example6 is a sectional view showing a flow path according to the sixth embodiment.
FIG. 16 of the present invention.Reference example6 otherReference exampleFIG. 3 is a cross-sectional view in the flow channel direction showing the flow channel of FIG.
FIG. 17 is an embodiment of the present invention.1It is a top view which shows the fluid flow path plate by.
FIG. 18 is an embodiment of the present invention.1FIG. 4 is a partially enlarged cross-sectional view of a fluid flow path plate according to the first embodiment.
FIG. 19 is an embodiment of the present invention.3It is a sectional view showing a dehumidifying device according to the present invention.
FIG. 20 is an embodiment of the present invention;4It is a flowchart which shows the structure of the air purifier based on FIG.
FIG. 21 is an embodiment of the present invention;51 is a cross-sectional view showing a configuration of a fuel cell according to the present invention.
FIG. 22 of the present invention.Reference Example 7FIG. 2 is a sectional view showing a hydrogen gas concentration sensor according to the first embodiment.
FIG. 23 of the present invention.Reference Example 81 is a cross-sectional view showing an electrolytic cell according to the present invention.
FIG. 24 is an embodiment of the present invention;61 is a cross-sectional view showing a gas purification device according to the present invention.
FIG. 25 is a cross-sectional view showing a configuration of a conventional fuel cell.
FIG. 26 is a plan view showing a configuration of a fluid flow plate of a conventional fuel cell.

Claims (2)

Fluid flow path for supplying a fluid containing moisture to the anode electrode of a fuel cell or fluid for supplying a fluid containing moisture to the anode electrode of a dehumidifier that applies a DC voltage to perform dehumidification by an electrochemical reaction A fluid flow plate having a flow path ,
The fluid flow path has a plurality of flow path portions arranged in parallel to branch and flow the fluid,
A fluid flow plate, wherein a fluid control member using a polymer water-absorbing material that absorbs and swells water contained in a fluid flowing through each flow path is provided on an outlet side of each flow path. To supply a fluid containing hydrogen to the anode electrode of a hydrogen purifier that purifies hydrogen by an electrochemical reaction by applying a DC voltage or a fluid flow path for supplying a fluid containing hydrogen to the anode electrode of a fuel cell A fluid flow plate having a fluid flow path of
The fluid flow path has a plurality of flow path portions arranged in parallel to branch and flow the fluid,
At the outlet side of each flow path, the hydrogen contained in the fluid flowing through each flow path absorbs the hydrogen when the concentration is equal to or higher than a predetermined concentration, swells and releases the hydrogen when the concentration is lower than the predetermined concentration. A fluid flow plate provided with a fluid control member using a contracting hydrogen storage alloy.

Images