JP2007220637A - Fuel cell power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell generator capable of effective utilization of energy, reduction of auxiliary equipment, and reduction of consumption energy by reducing and preventing dew formation at the time of mixture of supplied gas and surplus gas, making unnecessary cooling water for cooling the fuel cell, and heating and humidifying fuel gas (hydrogen gas) and oxidant gas (air) by utilizing waste heat. <P>SOLUTION: In a fuel cell power generator in which power is generated using the supplied gas and the surplus gas is exhausted to the outside, the supply route of the supplied gas is formed three-dimensionally inside the fuel cell, and at the same time as cooling of the fuel cell, the supplied gas is heated and supplied to the electrode part of the fuel cell, and the surplus gas exhausted from the fuel cell is reutilized by mixing with the supplied gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a fuel cell power generator that uses exhaust heat / exhaust gas of a fuel cell, in particular a polymer electrolyte fuel cell, to heat and humidify a supply gas, reduce auxiliary devices, and reduce energy consumption. It is.

Conventionally, from the viewpoint of efficient energy utilization, attention has been paid to fuel cells that utilize the fact that water and electricity are generated by the reaction of hydrogen and oxygen (air). Among them, attention is particularly focused on a polymer electrolyte fuel cell (hereinafter referred to as PEFC) that can be reduced in size and weight at an operating temperature of about 70 to 80 ° C. However, when trying to generate electricity only with a fuel cell such as PEFC, the fuel cell has a poor output response to the output fluctuation of the external load, and therefore, for example, an uninterruptible power supply that requires instantaneous power supply. The introduction of was difficult.

However, in recent years, there has been a movement to adopt fuel cells such as PEFC in the field of backup power sources. For many years, lead-acid batteries have been used in the field of backup power supplies, but have the disadvantage of taking up space. Moreover, in order to supply electric power for a long time, the number of storage batteries must be increased, resulting in an increase in the size of facilities. On the other hand, fuel cells such as PEFC can generate electricity continuously as long as fuel (hydrogen gas or oxygen gas) is supplied, so it is possible to suppress the increase in equipment size even when power is supplied for a long time. It is.

When a fuel cell such as PEFC is used as a backup power source, the following drawbacks can be mentioned.
(1) Low power generation efficiency (Warming water using waste heat and using it for hot water supply will increase overall efficiency, but backup power supply does not require hot water)
(2) Cost is high (3) Maintenance of auxiliary equipment is complicated (4) Energy is required to operate auxiliary equipment As mentioned above, fuel cells such as PEFC are difficult to use as current backup power sources There is. Further, the above problem cannot be avoided even in cases other than the use for backup power. Therefore, with the aim of reducing the consumption of fuel (hydrogen) gas and oxidant (oxygen or air) gas supplied to the fuel cell and improving the output characteristics by increasing the utilization rate of hydrogen, fuel Recirculation type fuel cell system that circulates exhaust gas from the fuel electrode of the battery, mixes it with fuel gas newly supplied from the outside, and supplies it to the fuel electrode of the fuel cell, and prevention of condensation in the gas passage Various methods have been proposed.

For example, in a fuel cell system composed of a fuel cell and a gas humidifier, the gas humidifier of the gas humidifier heats the fuel gas or oxidant gas with the combustion gas from the combustor, and the first humidifier In the oxygen electrode exhaust gas, water vapor passes through the water vapor permeable membrane and is given to the oxidant gas. The heated fuel gas is introduced into the second humidifier, and the vapor in the hydrogen gas exhaust gas is introduced into the second humidifier. Permeating through the water vapor permeable membrane and applied to the fuel gas, and supplying the fuel cell with the oxidant gas humidified by the first humidifier and the fuel gas humidified by the second humidifier (Patent Document 1) The hydrogen gas supply system of the fuel cell system is provided with a hydrogen circulation line that joins and mixes the exhaust gas discharged from the fuel cell main body with the newly supplied hydrogen gas and recirculates it to the fuel cell main body. And burn A humidifier is disposed between the fuel electrode inlet of the battery body and the junction, and a moisture recovery means for recovering moisture in the fuel gas after mixing at the junction is provided between the junction and the humidifier. (Patent Document 2) and the like are performed.

JP 2003-17097 A JP 2002-246059 A

The method described in Patent Document 1 uses a water vapor permeable membrane in a humidifier that humidifies a supply gas using exhaust gas from a fuel cell. In this case, dew condensation occurs on the surface of the membrane, and the permeation of water vapor may be hindered, and it is necessary to maintain the permeability of the water vapor permeable membrane. Therefore, the supply gas is heated to reduce the temperature difference between the battery exhaust gas and the supply gas in the supply gas humidification section, thereby preventing the battery exhaust gas from being cooled and causing condensation.
The method described in Patent Document 2 removes water from the recirculated hydrogen gas, and then mixes the recirculated hydrogen gas with the newly supplied hydrogen gas, and also removes water from the mixed gas (gas-liquid separation method). Is. Further, the temperature of the pressurized air before supply to the fuel cell is higher than the mixed hydrogen before supply, and the mixed hydrogen is heated using the heat of the pressurized air. Then, by heating the supply gas, the temperature difference between the exhaust gas and the supply gas is reduced, condensation is prevented, the supply gas is heated, and only the moisture of the exhaust gas is humidified by the supply gas.

However, each of the methods described in the patent documents is intended to prevent condensation of the water vapor permeable membrane and to prevent condensation after mixing the supply gas and surplus gas, and to reuse the surplus gas and to cool the fuel cell. It has not been done to eliminate the need for cooling water and to reduce the power consumption of auxiliary equipment (heaters and humidifiers).

Under such circumstances, cooling water for cooling the fuel cell is not required, and exhaust gas is used to heat and humidify the fuel gas (hydrogen gas) and oxidant gas (air) that are supply gases. Therefore, to provide a fuel cell power generator capable of effectively using energy, reducing auxiliary equipment, reducing energy consumption, and further reducing / preventing condensation when mixing supply gas and surplus gas. Is desired.

The present invention provides a fuel cell power generator that generates power using a supply gas such as hydrogen gas or oxygen gas, and discharges surplus gas to the outside. The supply gas is heated and supplied to the electrode part of the fuel cell simultaneously with the cooling of the fuel cell.

In addition, the supply gas is heated when the supply gas and the high-temperature surplus gas discharged from the fuel cell are mixed and reused.

Conventionally, moisture is necessary for hydrogen ions to move in the electrolyte of PEFC, and if this moisture is insufficient, ions are not moved well, and concentration polarization increases. Further, when low-temperature hydrogen gas or oxygen gas is supplied to the PEFC, the catalyst (platinum or the like) inside the PEFC is cooled, and the activity of the catalyst is reduced. On the contrary, if the internal temperature becomes too high, the performance of the fuel cell is lowered and the life is shortened. Further, hydrogen gas and oxygen gas supplied to the PEFC are humidified and heated, and the heat in the PEFC is cooled by circulating water. Then, auxiliary devices such as a pump and a humidifier are required for humidification / heating of hydrogen gas and oxygen gas and circulation of cooling water, and these electric powers are supplied by the generated power of PEFC itself. As a result, the cost of auxiliary equipment, power consumption, maintenance labor, and the like have occurred.

When operating a fuel cell, it is necessary to keep the internal temperature of the fuel cell at an appropriate temperature. If the temperature is too low, the catalytic activity will be low, and if it is too high, the fuel cell will deteriorate and the performance will deteriorate. When the fuel cell is actually operated, heat is generated due to oxidation / reduction reaction, concentration polarization, etc., and thus cooling is required.
According to the first aspect of the present invention, the supply path of the supply gas is formed three-dimensionally inside the fuel cell, and the supply gas is heated simultaneously with the cooling of the fuel cell. The heat generated at the electrode diffuses into the separator, etc., but by supplying a supply gas such as a fuel gas and an oxidant gas at a temperature lower to medium temperature than the PEFC main body to the gas supply path in the separator, the heat of the separator is supplied into the supply gas. Is diffused and the gas is heated. Since the flow path is three-dimensional, the contact area between the supply gas and the separator is increased, and the structure is suitable for heat exchange. Moreover, since the periphery of the flow path in the separator is cooled, the generated heat is diffused to this portion, and the fuel cell can be cooled. In this way, the supply gas is heated through the separator and the fuel cell is cooled. When the supply path is short as in the conventional case, the effect of cooling the PEFC main body is not so much obtained even when the fuel gas and the oxidant gas are at a low temperature.
Here, the three-dimensional formation of the supply path in the present invention means that the supply path formed in the conventional plane has a depth (z-axis) and is formed three-dimensionally long. Is formed long by zigzag or lattice.

Since the PEFC main body has the structure of the present invention, it is not necessary to use cooling water for cooling the PEFC main body as in the past, and auxiliary equipment (pumps, cooling water, etc.) can be reduced. It is possible to save the cost of equipment, power consumption and maintenance. Further, power consumption of a heater or the like for heating hydrogen gas and air can be reduced, and auxiliary devices can be reduced in size.
In the present invention, the high temperature is 70 ° C or higher, the intermediate temperature is 50 ° C or higher and lower than 70 ° C, and the low temperature is a range lower than 50 ° C.
When the supply path is not three-dimensional (planar / short) as in the prior art, the effect of cooling the PEFC main body is not very obtained even when the fuel gas and the oxidant gas are at low temperatures.

According to the second aspect of the present invention, when the supply gas and the high-temperature surplus gas discharged from the fuel cell are mixed and reused, the high-humidity surplus gas is cooled by the low-temperature supply gas and condensation occurs. (Due to temperature difference) Then, the condensed water generated by the dew condensation flows into the fuel cell, causing clogging and hindering gas diffusion, and thus the output may be lowered. Therefore, by heating the low-temperature supply gas in advance, the temperature difference between the supply gas and the surplus gas can be reduced, so that condensation of the mixed gas can be reduced or prevented.

According to the present invention, it is possible to cool the PEFC main body without circulating the cooling water by forming the supply gas supply path three-dimensionally inside the fuel cell, and at the same time, heating the supply gas. It is possible to carry out, and it is possible to effectively use energy, reduce auxiliary devices, and reduce energy consumption.
Further, when the supply gas and the surplus gas are mixed, dew condensation may occur due to the temperature difference between the two gases. This can be prevented by heating the supply gas.

An embodiment of the present invention will be described with reference to FIGS. In addition, the same number is attached | subjected to the same component.

FIG. 1 shows a single cell structure of PEFC in the present invention. As shown in FIG. 1, a single cell of PEFC 5 has a structure in which a membrane / electrode assembly (hereinafter referred to as MEA) 51 is sandwiched between a separator 52 on the fuel electrode side and a separator 53 on the air electrode side. The MEA 51 is composed of an ion exchange membrane 511, a catalyst layer 512 and a diffusion layer 513 disposed opposite to each other (the catalyst layer 521 and the diffusion layer 513 are collectively referred to as an electrode). Each of the rectangular separators 52 and 53 has a large number of hollow supply paths 523 and 533, and a fuel gas (hereinafter referred to as hydrogen gas) and an oxidant gas as indicated by broken arrows through the supply paths 523 and 533, respectively. By supplying (hereinafter referred to as air), the hydrogen gas is separated into hydrogen ions and electrons on the catalyst layer 512 of the fuel electrode. Then, hydrogen ions move through the clusters in the ion exchange membrane 511 together with water, electrons move to the air electrode through an external circuit (not shown), and oxygen, electrons, and hydrogen ions are transferred to the air electrode. Reaction produces water. Electric power is obtained by the difference in electromotive force generated between the fuel electrode and the air electrode.

The direction of the groove of the separator is arranged so that the fuel electrode and the air electrode are orthogonal to each other. With such a structure, the electrode area can be widened.
As shown in FIG. 1, the separators 52 and 53 are three-dimensionally configured (broken arrows) so that the gas supply path is folded back in a zigzag manner. The three-dimensional structure shown in FIG. 1 is configured integrally with a mold so that the respective supply paths are equally spaced, and the separator portion other than the supply path is a substance that easily conducts heat (metal or carbon material). It is configured. Then, hydrogen gas is supplied from the hydrogen inlet 521 of the separator supply path formed and discharged from the hydrogen outlet 522. A similarly configured air electrode side is also supplied with supply gas (air) from the air inlet 531 of the supply path and discharged from the air outlet 532. Since the temperature of each supply gas is lower than that of the PEFC5 main body and the temperature difference between the PEFC main body and the supply gas is at least 10 ° C. or higher (the temperature of the PEFC main body is higher), the supply path of each supply gas is set inside the fuel cell. By forming the three-dimensional shape in FIG. 3, the PEFC 5 main body can be cooled. Further, the PEFC 5 main body is cooled by the supply gas, and at the same time, the supply gas can be heated by the heat of the PEFC main body while passing through the hydrogen flow path 523 and the air flow path 533.
In this way, by making the gas supply path three-dimensional, it becomes possible to cool the PEFC main body without circulating the cooling water, effectively using energy, reducing auxiliary equipment, and reducing energy consumption. Is possible.

Thereafter, the supply gas (hydrogen gas) undergoes an oxidation reaction at the fuel electrode, and the hydrogen ions move through the ion exchange membrane together with moisture in the hydrogen gas and reach the air electrode. On the other hand, the supply gas (air) is heated simultaneously with cooling the PEFC while passing through the air flow path 533. Thereafter, a reduction reaction occurs at the air electrode. Further, since the air is dry, the moisture that has moved from the fuel electrode can be evaporated, and the PEFC main body can be further cooled by the latent heat of evaporation generated at this time.
The latent heat of vaporization is a phenomenon that takes away heat when water evaporates. In general, each supply gas is humidified. However, when the air is highly humid, the moisture is difficult to evaporate, and thus the cooling effect due to latent heat of evaporation is reduced. Therefore, it is preferable to humidify only hydrogen gas. The water moving from the fuel electrode to the air electrode and the water generated at the air electrode are evaporated with dry air, and the cell or stack can be cooled by latent heat of evaporation.
In this embodiment, the single cell structure has been described. However, since the voltage of a single cell is low in a single cell, a plurality of single cells are stacked in series to adjust to a desired voltage to configure a high output PEFC5. It is usually done.

FIG. 2 shows a schematic view of the separator of the present invention. The structure shown in FIG. 2 is called a parallel type, and shows a planar structure (a) and a three-dimensional structure (b), respectively. In the planar structure (a), hydrogen gas or air is supplied from the supply gas inlet 521 (531), the supply gas is evenly distributed in the flow path, is supplied onto the electrode, and surplus gas is discharged 522 (532). On the other hand, the three-dimensional structure (b) forms a flow path so that the planar structure is overlapped in the z-axis direction. For example, when a three-layer structure is used, the first layer outlet, the second layer inlet, and the second layer It is possible to form a three-dimensional separator by joining the outlet of the first layer and the inlet of the third layer.

FIG. 3 shows a schematic view of the planar structure of another separator of the present invention. (A) is a snake type, (b) is a parallel snake type, and (c) is a grit type. These are three-dimensional structures by configuring the planar structure shown in (a) to (c) so that the flow paths are overlapped in the z-axis direction as in FIG. 2 (b).
Note that the three-dimensional structure is not limited to that shown here, and any structure may be used as long as the supply path has a depth (z axis) and is formed long.

FIG. 4 is a schematic diagram of a PEFC power generator showing a first embodiment of the present invention. 1 is a hydrogen cylinder, 4 is a humidifier, 5 is a fuel cell body, 6b is a temperature / humidity sensor, 61 is a temperature / humidity controller measured by the temperature / humidity sensor 6b, 7 is a blower, 8 is a cooler, and 91 is recovered water. A tank, 92 is makeup water, and 93 is a recovered water pump.

First, the path of the supply gas (hydrogen gas) supplied to the fuel electrode of the PEFC 5 will be described. The supply gas stored in the hydrogen cylinder 1 passes through the pipe H, is humidified to a desired humidity by the humidifier 4, and is supplied to the hydrogen inlet of the fuel electrode of the PEFC 5 main body. The supply gas supplied to the PEFC 5 is used for a chemical reaction between the fuel electrode and the air electrode, and surplus gas that cannot be used for the chemical reaction is discharged from the hydrogen outlet of the fuel electrode.
The hydrogen ions generated in the hydrogen electrode move to the air electrode together with the water in the cluster in the ion exchange membrane and react with oxygen in the air electrode to produce water. Some water also flows into the poles. Thereby, hydrogen gas will have some water | moisture content after reaction within PEFC5.

Next, the path of the supply gas (air) supplied to the air electrode of the PEFC 5 will be described. Oxygen or air is used as the oxidizing agent, and air is generally used because it does not require maintenance. In the embodiment of the present invention, air is used as an oxidizing agent, and outside air (air) is taken in using a blower 7. The air taken in by the blower 7 is pressurized and compressed and supplied to the air inlet of the air electrode of the PEFC 5. The air supplied to the PEFC 5 is used for a chemical reaction between the fuel electrode and the air electrode, and surplus gas that has not been used for the chemical reaction (hereinafter referred to as surplus air) is discharged from the air outlet of the air electrode. At this time, the excess air discharged from the air outlet contains a large amount of water, and the generated water is stored in the recovered water tank 91. This recovered water is sent from the recovered water pump 93 to the humidifier 4 and used for humidifying the supply gas.
The surplus air in the recovered water tank 91 that has not become moisture is released to the atmosphere via the exhaust valve 31.
In addition, since the excess air contains a large amount of moisture at a high temperature, it is possible to collect the moisture. However, cooling with the cooler 8 (rapid cooling of the excess air) collects more moisture. It is possible.

Here, the cooling method of PEFC5 and the heating method of supply gas are demonstrated. The supply gas supplied to the PEFC 5 main body is at a normal temperature, which is lower than the temperature of the PEFC 5 main body. Conventionally, the supply path (separator) of the supply gas has not a zigzag structure. In the present invention, the PEFC 5 main body can be cooled by providing the supply path with a zigzag structure inside the fuel cell and forming the supply path three-dimensionally. This is because the temperature of the supply gas and air is lower than the temperature of the PEFC 5 body, so that the PEFC 5 body can be cooled.
At the same time, the low-temperature supply gas is heated to about 70 to 80 ° C. by the heat generated from the PEFC 5 main body (the PEFC main body is about 70 to 80 ° C.). To reach. The operation temperature of PEFC5 is about 70 to 80 ° C. for heating the supply gas. Since the operation becomes difficult when the supply gas is at a low temperature, PEFC5 is operated by providing a supply gas having a corresponding temperature. This is because it is possible to operate even at a low temperature but the output decreases.
Therefore, by making the gas supply path three-dimensional, it is possible to cool the PEFC main body without circulating the cooling water, and it is possible to effectively use energy, reduce auxiliary equipment, and reduce energy consumption. It becomes.

In the PEFC 5, water is taken away from the fuel electrode (electroosmosis phenomenon) by the flow of ions in the ion exchange membrane. As a result, the ion exchange membrane is dried, and as a result, the output decreases due to an increase in electrical resistance. Therefore, in order to manage the moisture in the ion exchange membrane, a method of sending water from the outside (including water in hydrogen gas), a method of using the water generated in PEFC5, and managing the inside of the battery at high humidity The method of doing is mentioned. In the present embodiment, water is supplied to the supply gas by using the humidifier 4 using the method of sending water from the outside among the above methods. As the humidification method, a atomization method capable of atomizing a necessary amount of water as much as necessary was adopted.

A method for controlling the humidity of the humidifier 4 of the present embodiment will be described. The surplus air discharged from the air electrode of the PEFC 5 contains a large amount of moisture, and the humidity of the surplus air is measured by the temperature / humidity sensor 6b (air electrode side). The data measured by the temperature / humidity sensor 6b is signal-processed and sent to the temperature / humidity control device 61. Then, a signal is sent from the temperature / humidity control device 61 to the humidifier 4, and when it is lower than the reference value, the spray amount from the nozzle of water supplied from the recovered water pump 93 is increased, and the atomization amount of water is increased. The amount of water in the supply gas is increased, and conversely, if it is higher than the reference value, the amount of spray from the nozzle of water supplied from the recovered water pump 93 is reduced, and the amount of atomization of water is reduced to reduce the amount of supply gas Reduce the amount of water. In this way, the supplied hydrogen gas and atomized water are mixed to generate a supply gas containing moisture.
For example, when the reference value of the humidifier is 80% and the humidity measured by the temperature / humidity sensor 6b falls below 70%, which is the reference value, it is recovered by the signal sent from the temperature / humidity control device 61 to the humidifier 4. The amount of spray from the nozzle of water supplied from the water pump 93 is increased.

In the case where the supply path does not have a zigzag structure as in the prior art, the effect of cooling the PEFC 5 main body was not obtained much even when the temperature of the supply gas and air was low.
In the present embodiment, the supply path is configured to bend back three times in a zigzag manner in order to cool the PEFC 5 and heat the supply gas / air. However, the present invention is not limited to this configuration.
In this embodiment, the atomization method in which water is sprayed as a humidification method is used as a humidification method. However, a bubbler method in which a gas is bubbled into a hot water tank so that the gas is in a saturated water vapor state, an ultrasonic vibrator, and an injector. It is possible to use the atomization method of atomizing water by applying such mechanical vibration.

In the second embodiment of the present invention, surplus gas is circulated in the first embodiment, and the supply gas and surplus gas are combined and mixed for use. Condensation may occur when the supply gas and the surplus gas are combined and mixed, but condensation can be prevented by heating the supply gas in advance.

FIG. 5 is a schematic diagram of a PEFC power generator showing a second embodiment of the present invention. 2, 2 'are auxiliary heaters for heating hydrogen gas and air, 3 is a valve, and 6a is a temperature / humidity sensor.
As shown in FIG. 5, surplus gas discharged from the hydrogen outlet of the fuel electrode is connected to the pipe H and the valve 3, and reaches the valve 3 through the pipe H. The supply gas newly supplied from the hydrogen cylinder 1 and the surplus gas discharged from the PEFC are merged and mixed at the valve 3, reach the fuel electrode of the PEFC 5 via the humidifier 4, and are discharged from the PEFC. The excess gas is circulated. The supply gas and the surplus gas that are merged and mixed at the point of the valve 3 have a temperature difference and may cause condensation. Therefore, the supply gas is heated via the auxiliary heater 2 before being merged and mixed. By setting it as such a structure, since the temperature difference of supply gas and surplus gas reduces, dew condensation does not arise at the time of merging and mixing.
The cooling method of PEFC 5 and the heating method of the supply gas are as shown in the first embodiment.

Here, in the second embodiment, the supply gas (hydrogen gas and air) is heated by the auxiliary heater 2. The water supplied to the humidifier is heated, atomized from the nozzle, and sprayed in a state. Then, the supply gas is mixed with the atomized water so that the supply gas contains water, and the supply gas has a medium temperature. For example, when hydrogen gas is heated to 70 ° C. by the auxiliary heater 2 and the temperature combined with the surplus gas (about 80 ° C.) at the point of the valve 3 is about 80 ° C., it is supplied to the humidifier 4. When the water is heated to 70 ° C., the supply gas containing moisture discharged from the humidifier 4 becomes about 70 ° C. Then, the supply gas having reached about 70 ° C. is supplied to the hydrogen inlet of the fuel electrode.
Therefore, even when an auxiliary heater is used, the temperature difference between the PEFC main body and the supply gas is at least 10 ° C. or more as in the first embodiment (the temperature of the PEFC main body is higher). Is formed three-dimensionally inside the fuel cell, so that the PEFC 5 main body can be cooled. Further, the PEFC 5 main body is cooled by the supply gas, and at the same time, the supply gas can be heated by the heat of the PEFC main body while passing through the hydrogen flow path and the air flow path.

The temperature and humidity of the surplus gas and surplus air discharged from the PEFC are measured by temperature / humidity sensors 6a (fuel electrode side) and 6b (air electrode side), respectively. The temperature / humidity sensor 6a measures the temperature / humidity of the surplus gas, and the temperature / humidity sensor 6b measures the temperature / humidity of the surplus air. The data measured by the temperature / humidity sensor 6a is signal-processed and sent to the temperature / humidity control device 61. A signal is sent from the temperature / humidity control device 61 to the auxiliary heater 2. If the temperature is higher than the reference value, the set temperature is lowered. On the other hand, if it is lower than the reference value, control is performed to increase the set temperature.
The temperature of the auxiliary heater 2 was controlled to be about 70 ° C. For example, based on the operating temperature of 70 ° C. of the PEFC main body, when the temperature and humidity of the surplus gas and surplus air are lower than the values, the set values are increased, and conversely, the temperature and humidity of the surplus gas and surplus air are lower than the values. If it is high, decrease the setting value.
The control method of the humidifier 4 is as shown in the first embodiment.
Note that the hydrogen gas is heated by directly heating the pipe H with an auxiliary heater.
The outside air (air) is used by pressurizing / compressing the air taken in by the blower 7, but after the pressurization / compression, an auxiliary heater 2 'is disposed between the blower and the PEFC, and the auxiliary heater 2' is used for piping. You may supply to the air inlet of the air electrode of PEFC5 in the state heated and dried at high temperature.

FIG. 6 shows a temperature and humidity control method for the auxiliary heater and humidifier of the present invention. As shown in FIG. 6, in the present invention, the temperature control of each auxiliary heater 2 and the humidity control of the humidifier 4 are measured by the temperature / humidity sensors 6a and 6b, and the signal-processed data is transmitted to the temperature / humidity control device 61. The temperature of the auxiliary heater 2 and the humidity of the humidifier 4 are controlled in comparison with the reference values provided.
In the control of the temperature of the auxiliary heater and the humidity of the humidifier according to the present invention, a reference value for the temperature of the auxiliary heater 2 and the humidity of the humidifier 4 is provided, and it is determined whether it is higher or lower than the reference value, and the output is made accordingly. Make adjustments.

First, a method for controlling the auxiliary heater 2 will be described. Excess gas discharged from the fuel electrode side of the PEFC 5 main body is measured by a thermocouple connected to the outer periphery of the pipe, and is signal-processed by the temperature / humidity sensor 6a. At this time, since the thermocouple is connected to the outer periphery of the pipe, the measured value is corrected in consideration of the thermal conductivity of the pipe. Then, the data processed by the temperature / humidity sensor 6a is transmitted to the temperature / humidity control device 61, and the temperature of the auxiliary heater 2 is increased and decreased as compared with the reference value. The reference value of the temperature of the auxiliary heater 2 is 70 ° C., because the optimum operating temperature of the PEFC 5 main body is about 70-80 ° C.

Excess gas discharged from the fuel electrode of the PEFC 5 main body is measured by the temperature / humidity sensor 6a every one minute. When the value obtained by subtracting 70 ° C. (reference value) from the measured temperature is negative, that is, when the temperature of the surplus gas is lower than the reference value, the output of the auxiliary heater is increased according to the temperature difference. . Conversely, if the value obtained by subtracting 70 ° C. (reference value) from the measured temperature is positive, the output of the auxiliary heater 2 is reduced.

For example, the temperature for controlling the auxiliary heater is set to ± 8 steps in increments of 5 ° C. from the reference value. When the measured temperature is 81 ° C., the output of the auxiliary heater is dropped in two steps to 70 ° C., and the supply gas is heated and merged and mixed by the valve 3. Here, the setting of the auxiliary heater is in increments of 5 ° C., and when the temperature is less than 2.5 ° C., the setting value is lower by one step. Set down 3 levels).
As described above, if the supply gas from the low temperature cylinder and the high temperature surplus gas are directly mixed, condensation easily occurs. However, before the supply gas from the low temperature cylinder and the high temperature surplus gas are mixed, the auxiliary heater By heating the supply gas at 2, it is possible to prevent and reduce condensation.
In addition, it is preferable to apply a heat insulating material to the pipe H from the auxiliary heater 2 to the valve 3 to keep the temperature of the heated supply gas constant.
Therefore, even when an auxiliary heater is used, it is possible to cause a temperature difference between the PEFC main body and the supply gas, and by forming the supply path of each supply gas in three dimensions inside the fuel cell, the PEFC5 main body Cooling is possible.

Next, the control method of the humidifier 4 will be described. Excess air discharged from the air electrode side of the PEFC 5 main body is measured by a hygrometer connected to the pipe and is subjected to signal processing by the temperature / humidity sensor 6b. And the data signal-processed by the temperature / humidity sensor 6b was transmitted to the temperature / humidity control device 61, and compared with the reference value, the humidity of the humidifier 4 was controlled. The humidity reference range of the humidifier 4 is 80 to 95%. This is because the amount of water is small when the humidity is too low, so the electroosmosis phenomenon (the phenomenon that the water molecules themselves move with the movement of ions) does not work, and the power generation efficiency This is because of a decrease.

The surplus air discharged from the air electrode of the PEFC 5 main body is measured for humidity every minute by the temperature / humidity sensor 6b. When the value obtained by subtracting 80% from the measured humidity is negative, that is, when the surplus air humidity is lower than the reference value range (when the humidity is 80% or less), depending on the magnitude of the humidity difference Increase the output of the humidifier 4. Conversely, when the value obtained by subtracting 80% from the measured humidity exceeds 15%, the output of the humidifier 4 is decreased. Other than that, the output adjustment of the humidifier 4 is not performed.

Similarly to the temperature control, the humidity control is negative when the value obtained by subtracting 80% of the humidity from the measured humidity is negative, that is, when the excess gas humidity is lower than the reference value range. Increase the output of the humidifier accordingly. Conversely, when the value obtained by subtracting 80% from the measured humidity exceeds 15%, the output of the humidifier is decreased. For example, the humidifier is set to ± 4 steps in 5% increments. When the measured humidity is 71%, the output of the humidifier is increased by two stages to 90%. Here, the setting of the humidifier is in increments of 5%, less than 2.5% is set at the lower setting value, and 2.5% or more is set at the upper setting value (in the case of 73%, the auxiliary heater is set). Set up one step).
In the present invention, all devices requiring electric power such as an auxiliary heater and a temperature / humidity sensor were supplied from PEFC.

As described above, by using the fuel cell power generation device of the present invention, it is possible to cool the PEFC main body without circulating the cooling water, and at the same time, it is possible to heat the supply gas, which is effective in energy. It is possible to reduce use, auxiliary equipment and energy consumption.
Further, when the supply gas and the surplus gas are mixed, dew condensation may occur due to the temperature difference between the two gases. This can be prevented by heating the supply gas.

Schematic of single cell structure of PEFC of the present invention. The planar structure (a) and three-dimensional structure (b) of the separator of the present invention. Schematic (a)-(c) of the planar structure of the other separator of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Schematic of the PEFC power generator which shows the 1st Embodiment of this invention. Schematic of the PEFC power generator which shows the 2nd Embodiment of this invention. 1 is a schematic diagram of a temperature and humidity control apparatus showing an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen cylinder 2 Auxiliary heater 3 Valve 4 Humidifier 5 Fuel cell main body 52, 53 Separator 523, 533 Supply path 6a Temperature / humidity sensor 7 Blower 8 Cooler 91 Recovered water tank 92 Replenished water 93 Recovered water pump H Piping

Claims (2)

In a fuel cell power generator that generates power using the supplied gas and discharges excess gas to the outside, the supply gas supply path is three-dimensionally formed inside the fuel cell, and the supply gas is heated simultaneously with the cooling of the fuel cell And supplying the fuel cell to the electrode part of the fuel cell. 2. The fuel cell power generator according to claim 1, wherein the supply gas is heated when the supply gas and the excess high-temperature gas discharged from the fuel cell are mixed and reused.