JP5990798B2 - Power generator - Google Patents

Description

  The present invention relates to a power generation apparatus that generates power by supplying hydrogen to a fuel cell, and is particularly useful as a technique for preventing a decrease in power generation efficiency due to an impurity gas such as nitrogen.

  As a power generation apparatus that generates power by supplying hydrogen generated by a reaction between a hydrogen generating agent and a reaction liquid to a fuel cell, for example, the one disclosed in Patent Document 1 below is known. The power generation device includes a plurality of power generation cells that generate power by supplying fuel gas from one surface and oxygen from the other surface, and the plurality of power generation cells with the one surface facing inward. By holding, a cell holder that forms an internal space together with the plurality of power generation cells, and a fuel generator that is arranged in the internal space of the cell holder and generates fuel gas are provided.

  There is also known a system in which hydrogen gas is generated by a fuel generator provided outside and supplied to the internal space of a housing in which a power generation cell is held. In particular, in the latter method, there are a lot of nitrogen components in the air existing in the internal space and the fuel generator, and this is concentrated without being discharged from the internal space of the fuel cell, resulting in a relatively low hydrogen concentration in the internal space. There is a problem that the power generation efficiency of the fuel cell is lowered.

  As a technique for preventing such a decrease in power generation efficiency due to an impurity gas such as nitrogen, Patent Document 2 provides a valve in the discharge part of the hydrogen flow path of the power generation cell in the final stage so that the pressure becomes a certain level or more. There is known a power generation device that discharges impurity gas at the time. Patent Document 3 discloses a power generation device that detects the nitrogen concentration of gas discharged from the power generation cell and controls the purge valve so as to keep the nitrogen concentration below a certain level.

International Publication WO2009 / 122910 JP 2007-66784 A JP-T-2004-513485

  However, since the power generation device of Patent Document 2 does not detect the concentration of the impurity gas and discharges it by opening and closing the valve based on the detected value, excess hydrogen gas can be released at a relatively high concentration. There is sex. Further, if the amount of released impurity gas is set small, there is a concern that the impurity gas remains in the hydrogen flow path of the power generation cell.

  On the other hand, in the power generation device of Patent Document 3, since the nitrogen concentration or the like is detected, it is possible to discharge the impurity gas more appropriately, but in order to detect the nitrogen concentration, a complicated measuring device is required, The manufacturing cost is also disadvantageous. Further, since the power generation efficiency of the fuel cell has already decreased in a state where the nitrogen concentration has increased, it can be said that it is difficult to maintain a sufficient power generation efficiency in total.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power generation device that can automatically discharge impurity gas with a simple device configuration and can suppress a decrease in the output of the fuel cell at that time. .

  The above object can be achieved by the present invention as follows.

  That is, the power generation device of the present invention includes an output fuel cell that generates power using hydrogen supplied to a flow path space provided on the anode side, and a gas discharged from the flow path space to the flow path space provided on the anode side. A detection fuel cell that generates power using hydrogen contained in the gas, a valve that is connected to a flow path space of the detection fuel cell and that can be opened and closed by an electrical signal, and Load means electrically connected to the output section, and control means for sending an operation signal to the valve to open when the output is reduced based on the output of the detection fuel cell.

  According to the power generation device of the present invention, since the detection fuel cell that guides the gas discharged from the output fuel cell and generates power with hydrogen contained in the gas is provided, impurities from the output of the detection fuel cell It is possible to detect a state in which the gas concentration has increased. In addition, since the opening and closing of the valve is controlled by the control means that opens when the output drops based on the output, it is possible to automatically discharge the impurity gas through the valve when the concentration of the impurity gas rises. The concentration of the impurity gas existing in the flow path space of the fuel cell can be kept below a certain level. Furthermore, even if the concentration of the impurity gas existing in the flow passage space of the detection fuel cell rises to some extent, the impurity gas is discharged from the flow passage space of the output fuel cell provided upstream thereof. Therefore, the output of the output fuel cell hardly decreases. Furthermore, load means is connected to the output portion of the detection fuel cell, and the detection fuel cell has a function of sucking gas by consuming hydrogen, so that gas can be efficiently discharged from the upstream output fuel cell. It can be discharged. As a result, it has been possible to provide a power generator that can automatically discharge impurity gas with a simple device configuration and can suppress a decrease in the output of the fuel cell.

  In the above, the control means sends an operation signal for opening operation when the output of the fuel cell for detection falls below a first threshold value, and sends an operation signal for closing operation when the output of the fuel cell for detection falls above a second threshold value. The first threshold value is preferably 95% or less of the second threshold value. Thus, by providing a difference of 5% or more between the first threshold value and the second threshold value, it is possible to maintain the impurity gas concentration below a certain level while preventing the valve from opening and closing too frequently.

  The power generation device of the present invention further includes hydrogen generation means for generating hydrogen by the reaction of the hydrogen generating agent and the reaction liquid, and is particularly effective when supplying the generated hydrogen to the flow passage space of the output fuel cell. is there. That is, when such a hydrogen generation means is provided, the amount of impurity gas such as nitrogen present in the hydrogen generation means increases, so that the impurity gas can be automatically discharged, and at that time, the output of the fuel cell is reduced. The power generation device of the present invention that can suppress the decrease is more effective.

  A plurality of the output fuel cells are electrically connected in parallel, and each of the output fuel cells is provided with the detection fuel cell, the valve, and the load means, and the control means Preferably, the valves are each controlled. In this way, by connecting a plurality of output fuel cells in parallel, it is possible to output larger power while preventing a decrease in power generation efficiency of the output fuel cells.

It is a figure which shows an example of the electric power generating apparatus of this invention, (a) is a block diagram, (b) is sectional drawing of the principal part. The flowchart which shows an example of the control in the electric power generating apparatus of this invention The block diagram which shows the other example of the electric power generating apparatus of this invention The flowchart which shows an example of the control in the electric power generating apparatus of this invention Graph showing results in Experimental Example 1 Graph showing results in Experimental Example 2

  As shown in FIGS. 1A and 1B, the power generator of the present invention is provided on the anode side with an output fuel cell 10 that generates power with hydrogen supplied to the flow passage space 11 provided on the anode side. The fuel cell for detection 20 which guides the gas discharged | emitted from the said flow-path space 11 to the flow-path space 20a, and produces electric power with the hydrogen contained in the gas is provided. A valve 21 that can be opened and closed by an electrical signal is connected to the flow path space 20a of the detection fuel cell 20, and a load means 22 is electrically connected to the output portion of the detection fuel cell 20, Based on the output of the fuel cell 20 for detection, the control means 23 which sends the operation signal to open to the valve 21 at the time of an output fall is provided. In the present embodiment, an example of an apparatus that generates electricity by supplying hydrogen generated in the hydrogen generator 30 to a series of output fuel cells 10 is shown.

  The hydrogen generator 30 includes a fuel generator that contains a hydrogen generating agent that reacts with a reaction liquid such as water to generate hydrogen gas. The reaction liquid is supplied to the fuel generation unit, and the generated hydrogen gas is supplied to the flow path space 11 of the output fuel cell 10. As the reaction liquid, a liquid that reacts with a hydrogen generating agent to generate hydrogen gas is used. Specifically, water, an acid aqueous solution, an alkaline aqueous solution, or the like is used depending on the type of the hydrogen generator.

  As the hydrogen generator, one that generates hydrogen gas by reacting with the reaction solution is used. For example, a hydrogen generating agent that reacts with a reaction solution such as water to generate hydrogen gas or a highly reactive hydrogen generating agent embedded in a resin can be used. Among these, from the viewpoint of controlling the reactivity, a resin in which a highly reactive hydrogen generator is embedded is preferable.

  Examples of such highly reactive hydrogen generators include calcium hydride, lithium hydride, potassium hydride, sodium borohydride, potassium borohydride, lithium aluminum hydride, sodium aluminum hydride, or magnesium hydride. And those containing a metal hydride compound.

  Moreover, you may contain metals, such as aluminum, iron, magnesium, and calcium, metal hydrogen complex compounds other than the above, as hydrogen generating agents other than the said compound. A plurality of metal hydride compounds, metals, and metal hydride complex compounds can be used in combination, or they can be used in combination.

  When embedding the hydrogen generator in the resin, the average particle size of the granular hydrogen generator is preferably 1 to 100 μm, more preferably 6 to 30 μm, from the viewpoint of controlling dispersibility and reactivity in the resin. 8-10 micrometers is still more preferable.

  The content of the hydrogen generating agent is preferably 10 to 80% by weight, and preferably 60 to 80% by weight in the resin from the viewpoint of ensuring appropriate reactivity and a certain amount of hydrogen generation.

  Examples of the resin used include a thermosetting resin, a thermoplastic resin, and a heat resistant resin, and a thermosetting resin is preferable. Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, acrylic resin, fluororesin, polyester, and polyamide. Examples of the heat resistant resin include aromatic polyimide, polyamide, and polyester.

  Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, phenol resins, amino resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. Especially, an epoxy resin is preferable from a viewpoint which can maintain a porous structure moderately during hydrogen generating reaction.

  The hydrogen generating agent may contain other components such as a catalyst, a filler, and a foaming agent as optional components other than the above components. As the catalyst, an alkali compound such as sodium hydroxide, potassium hydroxide and calcium hydroxide is also effective in addition to the metal catalyst for the hydrogen generator.

  Hydrogen gas generated by the hydrogen generator 30 is supplied to the flow passage space 11 of the output fuel cell 10 through the supply port 13. An ammonia removing agent may be provided in the hydrogen generator 30 or in a hydrogen supply path from the hydrogen generator 30 in order to remove ammonia as an impurity from the generated hydrogen gas. Such an ammonia removing agent is commercially available in the form of a sheet, but it is also possible to use one in which a granular adsorbent or the like is contained in a breathable bag.

  As the ammonia removing agent, for example, an adsorbent that adsorbs and removes ammonia in hydrogen (including chemical adsorption such as adsorption / decomposition and reaction adsorption), an absorbent that dissolves and removes ammonia, a reactant that removes ammonia by reaction, Examples include decomposition means for removing ammonia by decomposition (thermal decomposition, catalytic reaction decomposition, etc.), and it is preferable to provide an adsorbent that removes ammonia by physical adsorption or chemical adsorption.

  Among them, it is more preferable that the adsorbent is one that removes ammonia by physical adsorption or chemical adsorption, solid acid, activated carbon (excluding those corresponding to solid acids), zeolite (excluding those corresponding to solid acids), And at least one selected from the group consisting of molecular sieves. Among these, it is preferable to use a solid acid from the viewpoint of adsorption / removal ability of ammonia and a viewpoint capable of adsorption at a higher temperature.

  As shown in FIG. 1B, the output fuel cell 10 is provided with a flow path space 11 on the anode side, and can generate electric power with hydrogen supplied thereto. In the present embodiment, an example is shown in which a plurality of unit cells are held by the cell holder 12 with the anode side inside, and connected in series.

  In the present invention, the pressure of the hydrogen gas supplied to the flow path space 11 of the output fuel cell 10 is preferably 5 to 100 kPa from the viewpoint of efficiently discharging the internal impurity gas, and from the viewpoint of the pressure resistance of the power generation cell. 5-60 kPa is more preferable.

  In the present invention, the output fuel cell 10 includes a single unit cell or a plurality of unit cells. When the output fuel cell 10 includes a plurality of unit cells, the conductive layers of any unit cell and other unit cells are electrically connected to each other by a connecting portion. Connected. The electrical connection can be a series connection, a parallel connection, or a combination thereof. Note that the number of unit cells to be connected can be set according to the required voltage or current.

  Each unit cell in the present invention includes a solid polymer electrolyte layer 1, a first electrode layer 2 provided on both sides of the solid polymer electrolyte layer 1, and a unit cell as shown in the partially enlarged view of FIG. It has the 2nd electrode layer 3, and the 1st conductive layer and the 2nd conductive layer which were each arrange | positioned further outside these electrode layers 2 and 3. FIG. In the present embodiment, the first conductive layer and the second conductive layer are formed from the first metal layer 4 and the second metal layer 5 having exposed portions that partially expose the first electrode layer 2 and the second electrode layer 3. An example will be shown.

  Examples of the material for the conductive layer include metals, conductive polymers, conductive rubbers, conductive fibers, conductive pastes, and conductive paints.

  The solid polymer electrolyte layer 1 may be any solid polymer membrane type fuel cell as long as it is used, but from the viewpoint of chemical stability and conductivity, a sulfonic acid group that is a super strong acid is used. A cation exchange membrane made of a perfluorocarbon polymer is preferably used. Nafion (registered trademark) is preferably used as such a cation exchange membrane. In addition, for example, a porous film made of a fluororesin such as polytetrafluoroethylene impregnated with the above Nafion or other ion conductive material, a porous film made of a polyolefin resin such as polyethylene or polypropylene, or a non-woven fabric. A material carrying Nafion or another ion conductive material may be used.

  The thinner the solid polymer electrolyte layer 1 is, the more effective it is to make the whole thinner. However, in consideration of ion conduction function, strength, handling property, etc., 10 to 300 μm can be used, but 15 to 50 μm. preferable.

  The electrode layers 2 and 3 may be any as long as they cause an electrode reaction on the anode side and the cathode side near the surface of the solid polymer electrolyte layer 1. Among them, the one that exhibits the function as a gas diffusion layer to supply and discharge the fuel gas, the fuel liquid, the oxidizing gas, and the water vapor and at the same time exhibits the current collecting function can be preferably used. As the electrode layers 2 and 3, the same or different ones can be used, and it is preferable to support a catalyst having an electrode catalytic action on the base material. The catalyst is preferably supported at least on the inner surface side in contact with the solid polymer electrolyte layer 1.

  As the electrode substrate of the electrode layers 2 and 3, for example, conductive carbon such as carbon paper, fibrous carbon such as carbon fiber nonwoven fabric, and an aggregate of conductive polymer fibers can be used. It is also possible to use the electrode layers 2 and 3 that are attached to the solid polymer electrolyte layer 1 by directly attaching the catalyst to the solid polymer electrolyte layer 1 or supporting the catalyst on conductive particles such as carbon black.

  In general, the electrode layers 2 and 3 are prepared by adding a water-repellent substance such as a fluororesin to such a conductive porous material. When the catalyst is supported, a catalyst such as platinum fine particles and fluorine It is formed by mixing a water-repellent substance such as a resin, mixing it with a solvent to form a paste or ink, and then applying this to one side of an electrode substrate that should face the solid polymer electrolyte membrane. The

  In general, the electrode layers 2 and 3 and the solid polymer electrolyte layer 1 are designed according to the reducing gas and the oxidizing gas supplied to the fuel cell. In the present invention, it is preferable to use air as the oxidizing gas and hydrogen gas as the reducing gas. It is also possible to use a fuel liquid such as methanol instead of the reducing gas.

  For example, when hydrogen gas and air are used, the second electrode layer 3 on the cathode side on which air is naturally supplied (in this specification, the anode side is assumed to be the first electrode layer and the cathode side is assumed to be the second electrode layer). In this case, since a reaction between oxygen and hydrogen ions occurs and water is generated, it is preferable to design according to the electrode reaction. In particular, under the operating conditions of low operating temperature, high current density, and high gas utilization rate, the electrode porous body is likely to be clogged (flooded) due to the condensation of water vapor, particularly at the air electrode where water is generated. Therefore, in order to obtain stable characteristics of the fuel cell over a long period of time, it is effective to ensure the water repellency of the electrode so that the flooding phenomenon does not occur.

  As the catalyst, at least one metal selected from platinum, palladium, ruthenium, rhodium, silver, nickel, iron, copper, cobalt and molybdenum, or an oxide thereof can be used. A supported one can also be used.

  The thickness of the electrode layers 2 and 3 is more effective for reducing the overall thickness as the thickness is reduced. However, in consideration of electrode reaction, strength, handling property, etc., 1 to 500 μm is preferable, and 100 to 300 μm is more preferable. The electrode layers 2 and 3 and the solid polymer electrolyte layer 1 may be laminated and integrated in advance by adhesion, fusion, coating formation, or the like, or may simply be arranged in a stacked manner. Such a laminated body can also be obtained as a membrane / electrode assembly (MEA), and may be used.

  A first metal layer 4 on the anode side is disposed on the surface of the anode side electrode layer 2, and a second metal layer 5 on the cathode side is disposed on the surface of the cathode side electrode layer 3 (in this specification, the anode side Is the first metal layer and the cathode side is the second metal layer). The first metal layer 4 has an exposed portion that partially exposes the first electrode layer 2.

  The exposed portion of the first metal layer 4 may be any number, shape, size, formation position, etc. as long as the anode-side electrode layer 2 can be exposed. The opening of the anode side metal layer 4 is formed, for example, regularly or randomly by providing a plurality of circular holes, slits, or the like, or by opening a metal mesh, and the first metal layer 4 is shaped like a comb electrode. Thus, the anode side electrode layer 2 may be exposed. From the viewpoint of the balance between the contact area with the electrode and the supply area of the gas, the ratio of the area of the opening portion to be tightened (opening ratio) is preferably 10 to 50%, and more preferably 15 to 30%.

  Further, the second metal layer 5 on the cathode side has an exposed portion that partially exposes the second electrode layer 3. In this embodiment, oxygen in the air is supplied to the cathode side metal layer 5 (naturally An example in which a number of openings for intake) is provided. As long as the cathode-side electrode layer 3 can be exposed, the number, shape, size, formation position, etc. of the openings may be any. The opening of the cathode side metal layer 5 is, for example, provided with a plurality of circular holes or slits regularly or randomly, or provided with a metal mesh, and the second metal layer 5 is shaped like a comb electrode. Thus, the cathode side electrode layer 3 may be exposed. From the viewpoint of the balance between the contact area with the electrode and the supply area of the gas, the ratio of the area of the opening portion to be tightened (opening ratio) is preferably 10 to 50%, and more preferably 15 to 30%.

  As the metal layers 4 and 5, any metal can be used as long as it does not adversely affect the electrode reaction, and examples thereof include stainless steel plates, nickel, copper, and copper alloys. However, copper, a copper alloy, a stainless steel plate, and the like are preferable from the viewpoints of conductivity, cost, shape imparting property, strength for pressurization, and the like. Moreover, what gave metal plating, such as gold plating, to said metal may be used.

  In addition, although the thickness of the metal layers 4 and 5 is effective in reducing the overall thickness as the thickness is reduced, considering conductivity, cost, weight, shape imparting property, strength for pressurization, etc., the thickness is 10 to 1000 μm. Preferably, 50-200 micrometers is more preferable.

  When at least a part of the metal layer 4 and the metal layer 5 is exposed from the resin, electricity can be taken out using the part as an electrode. For this reason, although the terminal part which exposed the metal layer 4 and the metal layer 5 partially may be provided with respect to the resin molding 6, in this invention, in the case of series connection, the unit cell of the both ends is provided. It is preferable that the metal layer 4 or the metal layer 5 is provided with the protrusion part used as the electrode of a unit cell, and this has come out from the resin molding 6 outside. This protrusion can also be used to hold the metal layers 4, 5, etc. in the mold during insert molding.

  The formation of the metal layer 4 and the metal layer 5 and the formation of the opening can be performed using press work (press punching process). Moreover, you may provide a through-hole in the insert-molded part in the protrusion part of the metal layer 4 and the metal layer 5 in order to make the flow and adhesiveness of resin favorable.

  A resin molded body 6 in which the unit cells and the connection portions as described above are integrated by insert molding is provided. The resin molded body 6 preferably has a supply part for supplying gas or liquid to the first electrode layer 2 and the second electrode layer 3, and this supply part is the first metal layer 4 or the second metal layer 5. The opening 6a is preferably provided at a position corresponding to the exposed portion.

  In the present embodiment, the resin molded body 6 is pressed in a state where the first metal layer 4 and the second metal layer 5 are pressed from both sides so that the first electrode layer 2 and the second electrode layer 3 are exposed from the opening 6a. An example in which insert molding is performed and integrated is shown.

  In the present invention, the size of the opening corresponding to the exposed portions of the metal layers 4 and 5 may be larger, the same size, or smaller than the size of the opening 6 a of the resin molded body 6.

  Examples of the material of the resin molded body 6 include a thermosetting resin, a thermoplastic resin, and a heat resistant resin, and a thermoplastic resin and a thermosetting resin are preferable. Examples of the thermoplastic resin include polycarbonate resin, ABS resin, liquid crystal polymer, polypropylene, polystyrene, acrylic resin, fluororesin, polyester, and polyamide. Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, phenol resins, amino resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. Among these, polyester, polypropylene, and acrylic resin are preferable from the viewpoint of fluidity, strength, melting temperature, and the like of the resin in the mold, and these can be selected depending on the application.

  The overall thickness of the resin molded body 6 is preferably 0.3 to 4 mm, and more preferably 0.5 to 2 mm, from the viewpoints of the strength of integration with the resin, the pressure for pressing the metal layer, and the thinning. In particular, the thickness of the resin molded body 6 at the portion covering the metal layer is preferably 0.2 to 1.5 mm, and more preferably 0.3 to 1.0 mm, from the viewpoint of pressure to pressurize the metal layer.

  The resin molded body 6 is formed by insert molding a plate-shaped one in advance and joining it with other wall surfaces constituting the cell holding body 12 or by insert molding together with other wall surfaces constituting the cell holding body 12. It can be integrated with the cell holder 12.

  In the illustrated example, the output from the output fuel cell 10 is output to the outside as it is, but it can also be output to the outside through an output circuit. The output circuit is electrically connected to the output terminal of the power generation cell. The output voltage is preferably boosted to a predetermined voltage by a DC-DC converter (corresponding to a booster circuit). Furthermore, power is supplied from the connector to an external device, a mobile phone, or the like via a circuit portion added downstream of the converter. The circuit unit is provided with a stabilization circuit and the like, and is controlled so that an appropriate output voltage and output current can be supplied. The converter, the circuit unit, and the like are preferably configured as a circuit unit.

  The cell holder 12 has a hydrogen gas supply port 13 and a discharge port 14. Hydrogen gas generated by the hydrogen generator 30 is supplied from the hydrogen gas supply port 13. The hydrogen gas outlet 14 is connected to the flow path space 20 a of the detection fuel cell 20.

  The detection fuel cell 20 is provided with a flow path space 20a on the anode side, guides the gas discharged from the output fuel cell 10, and generates power with hydrogen contained in the gas. The structure of the unit cell in the detection fuel cell 20 can be the same as that of the output fuel cell 10. However, as shown in FIG. 1B, the detection fuel cell 20 is configured by fewer (for example, one or two) unit cells. In the illustrated example, one unit cell is held with the anode side inward only on one side of the cell holder.

  A valve 21 that can be opened and closed by an electrical signal is connected to the gas outlet 20b of the flow path space 20a of the fuel cell 20 for detection. As the valve 21, an electric valve such as an electromagnetic valve that can be opened and closed by an electric signal, a motor drive valve, a piezoelectric element drive valve (diaphragm), or the like can be used. The valve 21 may receive only an electric signal from the control means, or may receive power supply for valve operation. Since the gas discharged through the valve 21 has a low hydrogen concentration, it can be discharged as it is.

  The load means 22 is electrically connected to the output part of the detection fuel cell 20. The load means 22 is preferably a resistor, but a power storage means such as a battery or a capacitor, a load means using an electronic circuit, or an energy consuming means such as a lamp may be used.

  Based on the output of the detection fuel cell 20, the control means 23 sends an operation signal to open the valve 21 when the output decreases, and can be constituted by a microcomputer unit, a personal computer, or the like. As the control by the control means 23, it is possible to perform complicated control (proportional control, PID control, etc.) such as adjusting the opening degree of the valve 21 in accordance with the deviation between the detected output value and the threshold value. Alternatively, a method of performing on / off control based on a threshold value may be used.

  In the present invention, as shown in FIG. 2, when the output of the detection fuel cell 20 becomes equal to or lower than a first threshold value (for example, 0.20 V), the control means 23 sends an opening operation signal to the valve 21 to detect the detection fuel. When the output of the battery 20 becomes equal to or higher than a second threshold (for example, 0.24 V), it is preferable to perform control to send an operation signal for the closing operation to the valve 21. At that time, the first threshold value is preferably 95% or less of the second threshold value, and more preferably 90% or less.

  Moreover, it is preferable that the 2nd threshold value to set is 40 to 99% of the maximum output of the fuel cell 20 for a detection from a viewpoint of maintaining the impurity concentration of the gas discharged | emitted through the valve 21 appropriately. It is preferable that it is 50 to 98%. It is preferable that it is 50 to 95%.

  Such a process is performed as a loop process every predetermined time, and when the detected output value is between the first threshold value and the second threshold value, an operation signal is not sent. The processing interval is preferably 0.01 to 0.5 seconds, more preferably 0.02 to 0.2 seconds, from the viewpoint of securing the number of cell voltage measurements.

  Such control can be executed by, for example, a program stored in the microcomputer unit, and a set value can be changed by an external input.

  In the example shown in FIG. 1, a case where the microcomputer unit as the control means 23 receives power supply from the output fuel cell 10 is shown. In this case, the power stepped down or boosted by the DC-DC converter 31 is It is supplied to the control means 23. The control means 23 may receive power from only another power source (for example, a storage battery), or may receive power from both the other power source and the output fuel cell 10.

  When power is not supplied from another power source, the valve 21 is preferably open in the initial state. In that case, initially, sufficient hydrogen is supplied and the impurity gas in the system is discharged from the valve 21. As a result, the output from the output fuel cell 10 increases, and power is supplied until the control means 23 can operate, whereby normal control can be performed.

(Other embodiments)
(1) In the above-described embodiment, an example of an apparatus for generating power by supplying hydrogen generated in the hydrogen generator 30 to the output fuel cell 10 for one series is shown. The fuel cell 10 may be used to generate power. In that case, a plurality of output fuel cells 10 are electrically connected in parallel, and each of the output fuel cells 10 is provided with a detection fuel cell 20, a valve 21, and a load means 22, and a control means. It is preferable that each valve 21 is controlled by 23.

  The example shown in FIG. 3 is a power generator in which four series of output fuel cells 10 are electrically connected in parallel. Four times as much hydrogen is consumed by the four series of output fuel cells 10, and four times as much power can be output.

  The control means 23 controls the valves 21 of all systems by one program, and the control of the valves 21 of each system is the same as that of the above-described embodiment as shown in FIG. In this embodiment, as shown in FIG. 4A, when the control of the valve 21 of each system is performed as a loop process, the process based on the output value from the detection fuel cell 20 of each system is sequentially performed. Is programmed. It is also possible to control the valves 21 of each system independently and in parallel.

  (2) In the above-described embodiment, an example of an apparatus for generating power by supplying hydrogen generated in the hydrogen generator 30 to the output fuel cell 10 has been described. However, instead of the hydrogen generator 30, a hydrogen cylinder, hydrogen It is also possible to use hydrogen storage means such as a storage alloy. Even in this case, it is possible to effectively prevent a decrease in output due to an impurity gas such as nitrogen initially present in the flow path space of the output fuel cell 10. Further, in the power generation device as in the present invention, the hydrogen consumption in the output fuel cell 10 changes according to the power consumption. Therefore, using this property, the anode-side channel space 11 becomes negative pressure. In this case, the hydrogen generator 30 may be configured such that the fuel generator that contains the hydrogen generator can suck the reaction liquid.

  (3) In the above-described embodiment, an example in which a plurality of unit cells are held by the cell holder 12 with the anode side inside, and the flow path space 11 is provided on the anode side has been described. As the gas flow path for this purpose, one formed in advance for the unit cell or the plurality of unit cells may be used.

  In addition, as such a fuel cell, a fuel cell in which a unit cell provided with a flow path for supplying fuel or the like is provided independently on at least one side, or a stack type fuel with a separator interposed A battery or the like can be used.

  (4) In the above-described embodiment, an example of a power generation device in which the supplied hydrogen gas is discharged only from the valve 21 is shown. However, in the present invention, the gas is opened to any gas path at a pressure higher than a certain level. It is also possible to provide a safety valve. Further, instead of such a safety valve, a means for detecting pressure may be provided in any gas path, and the pressure in the path may be controlled below a certain level by opening / closing the valve 21 by an operation signal of the control means 23. Is possible.

  (5) In the above-described embodiment, the example in which the output from the detection fuel cell 20 is detected by the output voltage on both sides of the load means 22 has been shown. However, in the present invention, the method of directly measuring the current flowing through the load means 22 It is also possible to detect current.

Experimental example

  Examples of experiments for confirming the effects of the present invention will be described below.

Experimental Example 1 (Output reduction due to impurity gas)
The output fuel cell has the structure shown in FIG. 1 (b), and has two insert-molded planar cells (four unit cells connected in series, unit cell effective area 4 cm ² ) on both sides. Eight units that were held and formed with a channel space (26 mL) inside were used. At that time, the hydrogen gas path is connected in series to the eight units, and the eight units are connected in series so that the power generation cells on both sides of each unit are connected in parallel (4 × 8 series in two parallels). Connection).

  The following materials were used for insert molding. That is, a nickel plate having a plurality of openings plated with gold as a metal plate, a Nafion film as a solid polymer electrolyte layer (Nafion 112 manufactured by DuPont, 33 mm × 12 mm, thickness 15 μm), a platinum-supported carbon catalyst as a catalyst layer, an electrode layer Carbon paper (thickness: 370 μm, 33 mm × 12 mm), and resin (manufactured by Prime Polymer Co., Ltd., polypropylene resin, J-700GP) was used as a molding resin.

A fuel for detection in which only one unit cell (effective area is 4 cm ² ) as described above is held on one side at the gas outlet of this output fuel cell, and a flow path space (0.8 mL) is formed inside. The flow path space of the battery was connected. A resistor (0.4Ω) was electrically connected to the output of this detection fuel cell. A solenoid valve was provided at the gas outlet of the fuel cell for detection, and was manually opened and closed. The output of this output fuel cell was connected to an electronic load machine, and the load was set so that the output voltage was constant at 22.4 V (the output current was minimized until the set voltage was reached). The solenoid valve was opened, and hydrogen gas was supplied from a hydrogen cylinder to the gas supply port of the output fuel cell at a pressure of 20 kPa. After the voltage of each unit cell of the output fuel cell became substantially equal (after about 40 seconds), the solenoid valve was closed.

  FIG. 5 shows the voltages of the 10th, 12th, 14th, and 16th unit cells at this time. As shown in this figure, the supply of hydrogen gas gradually increases the voltage of each unit cell to a set voltage. When the set voltage is reached, due to the load by the electronic load machine, a pressure difference occurs and the hydrogen supply amount becomes unbalanced, and the voltage of the unit cell near the final stage drops, but eventually the hydrogen supply amount is balanced, The unit cell voltages are almost equal. When the solenoid valve is closed, the impurity gas is concentrated in the unit cell near the final stage, and the voltage of the unit cell near the final stage drops. Due to such partial voltage drop of the unit cell, the output current is reduced and the output (power) is reduced.

Experimental example 2 (when controlling a valve)
Next, an experiment was performed in which the opening and closing of the valve was controlled according to the output of the fuel cell for detection. When the microcomputer unit is programmed and the output of the fuel cell for detection falls below the first threshold (0.5 A), an opening operation signal is sent to the solenoid valve, and when the output exceeds the second threshold (0.6 A) Control to send the operation signal of the closing operation to the solenoid valve was performed. The loop processing interval in this control was set to 0.05 seconds. Except for performing such control, power was generated by supplying hydrogen under the same conditions as in Experimental Example 1.

  FIG. 6 shows the voltages of the 10th, 12th, 14th, and 16th unit cells at this time. As shown in this figure, the supply of hydrogen gas gradually increases the voltage of each unit cell to a set voltage. When the set voltage is reached, due to the load by the electronic load machine, a pressure difference occurs and the hydrogen supply amount becomes unbalanced, and the voltage of the unit cell near the final stage drops, but eventually the hydrogen supply amount is balanced, The unit cell voltages are almost equal. As that state approaches, the current of the output fuel cell becomes equal to or greater than the second threshold (0.6 A), and the electromagnetic valve is opened and closed by the control means. As a result, the impurity gas was efficiently discharged from the solenoid valve, and the output (voltage) drop of the unit cell close to the final stage could be prevented.

DESCRIPTION OF SYMBOLS 10 Output fuel cell 11 Channel space 12 Cell holder 13 Supply port 14 Discharge port 20 Fuel cell for detection 20a Channel space 20b Discharge port 21 Valve 22 Load unit 23 Control unit 30 Hydrogen generator 31 DC-DC converter

Claims (4)

An output fuel cell that generates electricity with hydrogen supplied to a flow path space provided on the anode side and outputs the output to the outside;
A fuel cell for detection that guides the gas discharged from the flow path space to the flow path space provided on the anode side, and generates power with hydrogen contained in the gas;
A valve connected to the flow path space of the fuel cell for detection and capable of opening and closing by an electrical signal;
A resistor electrically connected to the output of the fuel cell for detection;
Based on the output of the fuel cell for detection, a control means for sending an operation signal for opening operation when the output falls below a first threshold value, and for sending an operation signal for closing operation when the output of the fuel cell for detection rises above a second threshold value. And a power generation device.   The control means is configured to send an operation signal for an opening operation when the output of the fuel cell for detection becomes equal to or lower than a first threshold value, and to send an operation signal for a closing operation when the output of the fuel cell for detection becomes equal to or higher than a second threshold value. The power generation device according to claim 1, wherein the first threshold value is 95% or less of the second threshold value.   The power generation device according to claim 1, further comprising hydrogen generation means for generating hydrogen by a reaction between the hydrogen generating agent and the reaction liquid, and supplying the generated hydrogen to a flow path space of the output fuel cell. A plurality of the output fuel cells are electrically connected in parallel, and each of the output fuel cells is provided with the detection fuel cell, the valve, and the resistor. The power generator according to any one of claims 1 to 3, wherein each of the valves is controlled.

Images