JP2006318780A - Fuel cell power generator and fuel cell - Google Patents

Abstract

In order to realize highly stable operation of a fuel cell, a stable power generation is realized by making the dew point follow the cell temperature at the start of operation, which is particularly likely to be unstable.
Cooling of a cell composed of a polymer electrolyte membrane and cathodes (8a, 8b) serving as electrodes thereof is performed with cooling water in a cell cooling circuit (9) flowing through the inside of the cell. A cell temperature is detected by a cell outlet cooling water temperature sensor 14 attached to the outlet of the cooling water, and a hydrogen gas pressure adjusting valve 6 and an air pressure adjusting valve are detected by the arithmetic unit 15 according to the correlation between the cell temperature and the gas pressure. By calculating the opening degree of 5 and adjusting the opening degree, the dew point of the hydrogen gas 2 as the fuel gas and the air 1 as the oxidizing gas is controlled.
[Selection] Figure 1

Description

  The present invention relates to a power generation device that generates power from a fuel cell and a fuel cell using the power generation device, and is particularly applicable to a polymer electrolyte fuel cell.

  A fuel cell using a polymer electrolyte generates electric power and heat simultaneously by electrochemically reacting a fuel gas containing hydrogen and an oxidizing gas containing oxygen such as air. In the structure, first, a catalytic reaction layer composed mainly of carbon powder carrying a platinum-based metal catalyst is formed on both surfaces of a polymer electrolyte membrane that selectively transports hydrogen ions. Next, on the outer surface of the catalytic reaction layer, a diffusion layer is formed of, for example, carbon paper or carbon cloth having both air permeability of fuel gas and electronic conductivity, and the diffusion layer and the catalytic reaction layer are combined to form an electrode. To do.

  Next, a gas sealing material or gasket is placed around the electrode with a polymer electrolyte membrane sandwiched so that the supplied fuel gas or oxidizing gas does not leak outside or the fuel gas and oxidizing gas are mixed with each other. Deploy. This sealing material or gasket may be integrated with an electrode and a polymer electrolyte membrane and assembled beforehand, and this may be referred to as MEA (membrane electrode assembly).

  Outside the MEA, a conductive separator for mechanically fixing the MEA and connecting adjacent MEAs in series with each other is disposed. In the portion of the separator that contacts the MEA, a reaction gas is supplied to the electrode surface to form a gas flow path for carrying away the generated gas and surplus gas. The gas flow path can be provided separately from the separator, but a system in which a groove is provided on the surface of the separator to form a gas flow path is common.

  In order to supply the fuel gas to the groove of the separator, a pipe jig for branching the fuel gas supply pipe into the number of separators to be used and connecting the branch destination directly to the separator-like groove is required. . This jig is called a manifold, and the type connected directly from the fuel gas supply pipe as described above is called an external manifold. There is a type of this manifold called an internal manifold with a simplified structure. The internal manifold is provided with a hole penetrating the separator in which the gas flow path is formed, through the gas flow path to the hole and supplying fuel gas directly from the hole.

  Since the fuel cell generates heat during operation, it is necessary to cool the fuel cell with cooling water or the like in order to maintain the battery in a favorable temperature state. Usually, a cooling unit that allows cooling water to flow every 1 to 3 cells is inserted between the separator and the separator. However, a cooling water channel is often provided on the back surface of the separator to form a cooling unit. These MEAs, separators, and cooling units are stacked alternately, and after stacking 10 to 400 cells, it is generally sandwiched between end plates via current collector plates and insulating plates and fixed from both ends with fastening bolts. This is a structure of a laminated battery.

  In polymer electrolyte fuel cells, in order to facilitate movement of ionized hydrogen in the polymer electrolyte membrane, water vapor is mixed with gas containing hydrogen as the fuel gas or oxygen gas as the oxidant and supplied. It is common to do.

  On the other hand, since water (water vapor) is generated by the combustion reaction during power generation, the flow channel formed in the separator, the diffusion layer of the MEA, and the electrode part are generated by power generation with water vapor mixed with fuel and oxidant. Moisture (water vapor) passes through. The separator surface is generally controlled at a constant temperature so that the generated water does not condense more than necessary, but the amount of heat generated inside the fuel cell due to the consumption of generated power and changes in fuel supply. Changes, the internal temperature fluctuates and the amount of produced water fluctuates.

  For example, when the temperature is lowered, the separator surface is likely to condense, and it is impossible to completely eliminate such a phenomenon. When dew condensation occurs, water drops block the flow path, resulting in insufficient fuel supply to the electrode or catalyst after the plugged location, so the voltage gradually decreases, and when the water drops are discharged, There is a problem that a voltage instability phenomenon (flooding) occurs in which the fuel supply is restored and the voltage rises because the blockage is released.

  In particular, when the fuel cell is started up, if the fuel gas or oxidizing gas is supplied in a humidified state at the dew point of the predetermined temperature before the cell temperature reaches the predetermined temperature, the temperature is increased when the humidified gas is introduced into the cell. Therefore, the moisture contained in the humidified gas is condensed in the cell, and the gas diffusion performance in the dewed portion is abruptly lowered, so that the supply of the fuel gas and the oxidizing gas is lowered and the power generation performance is lowered.

  In order to solve such a problem, as proposed in Patent Document 1, for example, a fuel cell system as shown in FIG. 6 has been proposed. In FIG. 6, the fuel cell 40 is a cell comprising a water tank 42 that is a humidifying means for the oxidizing gas 41, a water tank 44 that is a humidifying means for the fuel gas 43, a cathode 45, a solid polymer electrolyte membrane 46, and an anode 47. 48 and a cooling part 49 of the cell 48.

And the starting method of the fuel cell system includes a first starting step for raising the temperature of the fuel cell 40 to stabilize the temperature at the time of starting the fuel cell 40, and a fuel gas 43 after completion of the first starting step. And a second start-up step that operates for a certain period of time under conditions where condensation occurs within the fuel cell in a short time due to the reaction of the oxidizing gas 41, and after the second start-up step is completed, the method shifts to a normal operation. .
Japanese Patent Application Laid-Open No. 2004-2131979

  However, in the operation of supplying a humidified gas having a dew point equal to the cell temperature after increasing the cell temperature as in the prior art, the cell is kept until the humidified fuel gas or oxidizing gas is stably supplied. There is a period in which only the temperature is in the elevated state. This period varies depending on the capacity of the hot water tank and the heater capacity for generating the humidified gas, but for example, it takes about 1 hour in the case of a tank capacity of 70 liters and a heater capacity of 5 kW.

  Generally, in the case of a cogeneration system that supplies electricity and gas for home use, the operation method is such that the start and stop are repeated frequently according to the daily life pattern. It cannot be ignored. That is, the polymer electrolyte membrane is damaged by being in a high-temperature and low-humidification state when starting and stopping.

  In the prior art, the fuel gas humidifying means and the oxidizing gas humidifying means are configured to store warm water in the tank, introduce gas into the warm water, and humidify the tank. In order to rapidly change the dew point, the tank It was necessary to change the temperature of the hot water stored in the tank, and it took time to raise the temperature due to the heat capacity of the tank and water.

  FIG. 8 illustrates changes in cell temperature and gas dew point in the prior art. t0 is the activation timing, and the cell temperature control heater is turned on by a command to increase the cell temperature, and the cell temperature rises. After the cell temperature rises to a predetermined temperature (70 ° C. in this case) at t1, humidified gas supply of fuel gas and oxidizing gas is started at timing t2. When the humidifying tank temperature reaches the temperature measured in advance (75 ° C in this case) as the humidifying tank temperature for setting the dew point of the humidifying gas to 70 ° C, and the timing when the dew point reaches 70 ° C is t3, the humidification inside the cell There is a period (t3-t2) in which the state is in a low humidified state where it does not reach saturation. When this period is repeated, the specific resistance of the polymer electrolyte membrane is increased, thermal damage is added, and the battery performance is lowered.

  Therefore, even when the fuel cell dew point and the oxidizing gas dew point reach the cell temperature when the cell temperature has risen at the start of operation of the fuel cell, the inside of the cell does not become a high temperature and low humidity state, or vice versa. It will be in a state of over-humidification so that moisture does not condense inside the cell, and the load connected to the fuel cell will not fluctuate, and even if the fuel supply amount fluctuates, the voltage will not drop or rise Therefore, it is required to provide a fuel cell having stable power generation performance. Realizing that is to enable high responsiveness of dew point manipulation following the change in cell temperature.

  An object of the present invention is to realize a highly stable operation of a fuel cell in view of the above-described prior art. In particular, a fuel that realizes stable power generation by causing the dew point to follow the cell temperature at the start of operation, which is likely to be unstable. The object is to provide a battery power generator and a fuel cell.

  In order to achieve the above object, according to the first aspect of the present invention, in the fuel cell power generator, the fuel gas pressure adjusting means for adjusting the pressure of the fuel gas supplied to the fuel cell and the pressure of the oxidizing gas supplied are adjusted. The pressure command value to the oxidizing gas pressure adjusting means and the fuel gas pressure adjusting means is calculated from the fuel cell temperature measured by the temperature measuring means installed in the fuel cell, and the pressure to the oxidizing gas pressure adjusting means And a calculation means for calculating the command value from the fuel cell temperature measured by the temperature measurement means.

  According to a second aspect of the present invention, in the fuel cell power generator according to the first aspect, the fuel gas pressure adjusting means is provided between the fuel gas humidifying means for humidifying the fuel gas and the fuel gas inlet provided in the fuel cell. An oxidant gas pressure adjusting unit is installed between an oxidant gas humidifying unit that is installed and humidifies the oxidant gas and an oxidant gas introduction port provided in the fuel cell.

  According to a third aspect of the present invention, in the fuel cell power generator according to the first or second aspect, the fuel gas heating means is installed between the fuel gas pressure adjusting means and the fuel gas inlet, and the oxidizing gas pressure adjusting means An oxidizing gas heating means is installed between the oxidizing gas inlet and the oxidizing gas inlet.

  According to a fourth aspect of the present invention, in the fuel cell power generator according to the third aspect, the fuel gas dew point measuring means is installed at least before or after the fuel gas heating means, and the dew point measured by the fuel gas dew point measuring means is set. A command value to the fuel gas pressure adjusting means is calculated and output so as to follow, and an oxidizing gas dew point measuring means is installed at least before or after the oxidizing gas heating means to follow the dew point measured by the oxidizing gas dew point measuring means. As described above, the dew point control means for calculating and outputting the command value to the oxidizing gas pressure adjusting means is provided.

  According to a fifth aspect of the present invention, in the fuel cell power generator, the first fuel gas humidifying means and the second fuel gas humidifying means for diverting and humidifying the fuel gas supplied to the fuel cell, and the first fuel gas The humidified fuel gas output from the first fuel gas humidifier and the humidified fuel gas output from the second fuel gas humidifier are installed after the humidifier and the second fuel gas humidifier. Fuel gas mixing means, first oxidizing gas humidifying means and second oxidizing gas humidifying means for diverting and humidifying the oxidizing gas supplied to the fuel cell, the first oxidizing gas humidifying means and the second oxidizing gas An oxidizing gas mixing means that is installed at a subsequent stage of the humidifying means and mixes the humidified oxidizing gas output from the first oxidizing gas humidifying means and the humidified oxidizing gas output from the second oxidizing gas humidifying means; The mixing ratio command value to the fuel gas mixing means is calculated from the fuel cell temperature measured by the temperature measuring means installed in the fuel cell, and the mixing ratio command value to the oxidizing gas mixing means is calculated by the temperature measuring means. An arithmetic means for calculating from the measured fuel cell temperature is provided.

  According to a sixth aspect of the present invention, in the fuel cell power generator according to the fifth aspect, the humidification temperature of the first fuel gas humidifying means is set higher than the fuel cell operating temperature, and the humidification of the second fuel gas humidifying means is performed. The temperature is set lower than the fuel cell operating temperature, the humidifying temperature of the first oxidizing gas humidifying means is set higher than the fuel cell operating temperature, and the humidifying temperature of the second oxidizing gas humidifying means is lower than the fuel cell operating temperature. It is characterized by being set to.

  According to a seventh aspect of the present invention, in the fuel cell power generator according to the fifth or sixth aspect, the fuel gas heating means is installed between the fuel gas mixing means and the fuel gas inlet, and the oxidizing gas mixing means and the oxidizing gas are provided. An oxidizing gas heating means is installed between the inlets.

  According to an eighth aspect of the present invention, in the fuel cell power generator according to the seventh aspect, the fuel gas dew point measuring means is installed at least before or after the fuel gas heating means, and the dew point measured by the fuel gas dew point measuring means is set. The command value to the fuel gas mixing means is calculated and output so as to follow, and the oxidizing gas dew point measuring means is installed at least before or after the oxidizing gas heating means so as to follow the dew point measured by the oxidizing gas dew point measuring means. And a dew point control means for calculating and outputting a command value to the oxidizing gas mixing means.

  The invention described in claim 9 is characterized in that, in the fuel cell, the fuel cell power generator according to any one of claims 1 to 8 is used as a power generation unit.

  The invention according to claim 10 is a fuel cell comprising a cell comprising a polymer electrolyte membrane and a pair of electrodes sandwiching the polymer electrolyte membrane, and a cooling circuit for cooling the cells, A sensor for detecting the dew point of the gas is provided on each gas suction side.

  According to the present invention, since the dew point of the humidified gas follows the cell temperature even in a transient state such as when the fuel cell is started up, the inside of the cell is in a high temperature and low humidified state, and the polymer is repeated by repeatedly starting and stopping. Stable power generation over the long term without deterioration of the electrolyte membrane or condensing moisture due to excessively humidified conditions, resulting in a decrease in fuel gas or oxidant gas supply rate, resulting in a decrease in power generation performance The state can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a polymer electrolyte fuel cell power generator for explaining Embodiment 1 of the present invention.

  In FIG. 1, 1 is an air that is an oxidizing gas, 2 is a hydrogen gas that is a fuel gas, 3 is an air humidifying tank that is an oxidizing gas humidifying means, 4 is a hydrogen gas humidifying tank that is a fuel gas humidifying means, and 5 is an oxidizing gas An air pressure regulating valve that is a pressure regulating means, 6 is a hydrogen gas pressure regulating valve that is a fuel gas pressure regulating means, 7 is a polymer electrolyte membrane, 8a is a cathode that is one electrode of the polymer electrolyte membrane 7, and 8b is high. The anode is the other electrode of the molecular electrolyte membrane 7, and a cell is constituted by the polymer electrolyte membrane 7, the cathode 8a, and the anode 8b.

  9 is a cell cooling circuit for cooling the cell, 10 is a high-temperature cooling water tank connected to the cell cooling circuit 9, 11 is a low-temperature cooling water tank connected to the cell cooling circuit 9, 12 is a cooling water mixing valve, and 13 is cell inlet cooling. A water temperature sensor, 14 is a cell outlet cooling water temperature sensor, 15 receives temperature information measured by the sensors 13 and 14, and calculates and outputs a pressure command value for the pressure regulating valves 5 and 6. An arithmetic unit comprising a CPU (Central Processing Unit) or the like.

  Here, a production method of a polymer electrolyte fuel cell (cell) common to the present embodiment will be described.

  First, a method for producing an electrode having a catalyst layer will be described. An electrode catalyst comprising 25% by weight of platinum particles having an average particle diameter of about 30% supported on acetylene black powder was used. A dispersion solution in which perfluorocarbonsulfonic acid powder was dispersed in ethyl alcohol was mixed with a solution in which the catalyst powder was dispersed in isopropanol to form a catalyst paste.

  On the other hand, the carbon paper which becomes a support body of an electrode was water-repellent treated. After impregnating a carbon non-woven fabric (TGP-H-120, manufactured by Toray Industries, Inc., outer dimensions 14 cm × 14 cm, thickness 360 μm) into an aqueous dispersion containing fluororesin (manufactured by Daikin Industries, NEOFLON ND1), this is dried. And water repellency was imparted by heating at 400 ° C. for 30 minutes.

A catalyst layer was formed on one surface of the carbon nonwoven fabric by applying the catalyst paste using a screen printing method. At this time, a part of the catalyst layer is embedded in the carbon nonwoven fabric. The catalyst layer thus prepared and the carbon nonwoven fabric were combined to form an electrode. Amount of platinum contained in the reaction electrode after forming the 0.6 mg / cm ^2, the amount of perfluorocarbon sulfonic acid was adjusted to be 1.2 mg / cm ^2.

  Then, a pair of electrodes are joined by hot pressing on both sides of the proton conductive polymer electrolyte membrane having an outer dimension of 15 cm × 15 cm so that the catalyst layer is in contact with the electrolyte membrane side, and this is joined to the electrode electrolyte membrane assembly (MEA). ). Here, as the proton conductive polymer electrolyte, a perfluorocarbon sulfonic acid thinned to a thickness of 30 μm was used.

Next, the conductive separator will be described. First, artificial graphite powder having an average particle size of about 50 μm is prepared, and 80% by weight of the artificial graphite powder is kneaded with an extruding kneader with 20% by weight of a thermosetting phenol resin. It put into the metal mold | die which gave the process for shape | molding the groove | channel for cooling water flow paths, and a manifold, and hot-pressed. The hot pressing conditions were a mold temperature of 150 ° C. and a pressure of 100 kg / cm ² for 10 minutes. The obtained separator had an outer size of 20 cm × 20 cm, a thickness of 3.0 mm, and a depth of the gas channel and the cooling water channel of 1.0 mm. Therefore, the thickness of the thinnest part of the separator is 1.0 mm.

  Here, the fuel cell power generator of Embodiment 1 will be specifically described with reference to FIG.

  The capacity of the air humidification tank 3 was 70 liters, the pressure resistance was 0.5 MPa, and the temperature was adjusted to 80 ° C. in this example. The capacity of the hydrogen gas humidification tank 4 was 20 liters, the pressure resistance was 0.5 MPa, and the temperature was adjusted to 80 ° C. in this example. The opening degree of the air pressure control valve 5 and the hydrogen gas pressure control valve 6 is measured by the cell outlet cooling water temperature sensor 14 with the cell temperature as the dew point to be set according to the relationship between the gas dew point and the gas pressure shown in FIG. The opening degree calculated by the arithmetic unit 15 is adjusted so as to obtain a corresponding pressure. Whether or not the pressure is set at this time is detected by a pressure sensor (not shown) attached to each of the humidifying tanks 3 and 4 to adjust the opening.

  The cell cooling is performed by adjusting the mixing ratio of the hot water in the cooling water high temperature tank 10 and the cooling water low temperature tank 11 with the cooling water mixing valve 12 for the cooling water supplied to the cell cooling circuit 9, and the cell temperature is set by power generation. If the temperature exceeds 70 ° C., it is cooled, and if it is below 70 ° C., it is heated. In this example, the water temperature of the cooling water low temperature tank 11 is 50 ° C., and the water temperature of the cooling water high temperature tank 10 is 85 ° C.

  When generating a fuel cell with the polymer electrolyte fuel cell and the fuel cell power generator of Embodiment 1 having the above-described configuration, first, the fuel cell is held at 70 ° C., and a dew point of 70 ° C. is provided on one electrode (anode 8b) side. The hydrogen gas 2 was humidified and heated so that the air was heated, and the humidified and heated air 1 was supplied to the dew point of 70 ° C. on the other electrode (cathode 8a) side.

  FIG. 9 shows a change state of the cell temperature and the gas dew point at the start-up. While the cell temperature was controlled at 70.5 ° C, the gas dew point was 68 ° C. As a reason for the difference of 2 ° C. with respect to the set temperature, dew condensation in the middle of the piping can be considered. As the power generation characteristics, a battery open voltage of 96 V was obtained at no load when no current was output to the outside. Moreover, when the internal resistance of the whole laminated battery at this time was measured, it was about 45 mΩ.

The fuel cell of Embodiment 1 was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 85%, an oxygen utilization rate of 50%, and a current density of 0.7 A / cm ² , and the time change of the output characteristics was measured. Starting and stopping was repeated every day, and starting and stopping was performed 300 times in about one year. As a result, it was confirmed that the fuel cell of Embodiment 1 maintained a battery output of about 14 kW (62V-224A) over a total of 8000 hours in total energization time.

(Embodiment 2)
FIG. 2 is a configuration diagram of a polymer electrolyte fuel cell power generator for explaining Embodiment 2 of the present invention. In the following description of the embodiments, members corresponding to those already described are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 2, two air high-temperature humidification tanks 18 and 19 are installed. The first air high-temperature humidification tank 18 has a capacity of 70 liters, a pressure resistance of 0.5 MPa, and is adjusted to a temperature of 80 ° C. The capacity of the air low-temperature humidification tank 19 was 20 liters, the pressure resistance was 0.5 MPa, and the temperature was adjusted to 50 ° C. Furthermore, two hydrogen gas high-temperature humidification tanks 20 and 21 are installed. The first hydrogen gas high-temperature humidification tank 20 is configured with a capacity of 20 liters and a pressure resistance of 0.5 MPa, and the temperature is adjusted to 80 ° C. The hydrogen gas low-temperature humidification tank 21 had a capacity of 10 liters and a pressure resistance of 0.5 MPa, and the temperature was adjusted to 50 ° C.

  The cathode humidified gas mixing proportional valve 16 as the oxidizing gas mixing means and the anode humidified gas mixing proportional valve 17 as the fuel gas mixing means measure the cell outlet cooling water temperature sensor 14 with the dew point to be set as the cell temperature. The mixture ratio is adjusted to the PID calculated by the calculation device 15 so that the dew point corresponds to the temperature. Other configurations are the same as those in the first embodiment.

  When the fuel cell is caused to generate power by the polymer electrolyte fuel cell and the fuel cell power generator of Embodiment 2 having the above-described configuration, as in Embodiment 1, the fuel cell is first maintained at 70 ° C., and is placed on one electrode side. Hydrogen gas 2 humidified and heated to a dew point of ° C. was supplied, and air 1 humidified and heated to a dew point of 70 ° C. was supplied to the other electrode side.

  While the cell temperature was controlled at 70.5 ° C., the gas dew point was 68 ° C. As the power generation characteristics, a battery open voltage of 96 V was obtained at no load when no current was output to the outside. Moreover, when the internal resistance of the whole laminated battery at this time was measured, it was about 45 mΩ.

The fuel cell of Embodiment 2 was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 85%, an oxygen utilization rate of 50%, and a current density of 0.7 A / cm ² , and a change in output characteristics with time was measured. Starting and stopping was repeated every day, and starting and stopping was performed 300 times in about one year. As a result, it was confirmed that the fuel cell of the second embodiment maintained a battery output of about 14 kW (62V-224A) over a total of 8000 hours as in the first embodiment.

(Embodiment 3)
FIG. 3 is a configuration diagram of a polymer electrolyte fuel cell power generator for explaining Embodiment 3 of the present invention.

  In the third embodiment, in addition to the configuration of the second embodiment, as shown in FIG. 3, an oxidizing gas heating means having a tubular structure in the middle of the piping until the air 1 is supplied to the fuel cell and incorporating a 1.5 kW heater. In the same manner, a hydrogen gas heater 23 which is a fuel gas heating means having a tubular structure in the middle of the pipe until the hydrogen gas 2 is supplied to the fuel cell and having a 1.5 kW heater built therein is provided. Equipped and the temperature control device 24 controls the temperature of both heaters 22 and 23.

  Further, an air dew point sensor 25 which is an oxidizing gas dew point measuring means for measuring a gas dew point immediately after the air heater 22 is arranged, and further a fuel gas dew point measuring means for measuring a gas dew point immediately after the hydrogen gas heater 23. A hydrogen gas dew point sensor 26 is arranged, and the calculation device 15 takes in the outputs of the dew point sensors 25 and 26 to perform PID calculation, and adjusts the mixing proportional values of both gas mixing proportional valves 16 and 17 by the calculation output. It was configured as follows. Other configurations are the same as those in the first and second embodiments.

  When the fuel cell is generated by the polymer electrolyte fuel cell and the fuel cell power generator of Embodiment 3 having the above-described configuration, as in Embodiments 1 and 2, first, the fuel cell is held at 70 ° C. The hydrogen gas 2 humidified and heated to a dew point of 70 ° C. was supplied, and the air 1 humidified and heated to a dew point of 70 ° C. was supplied to the other electrode side.

  While the cell temperature was controlled to 70.5 ° C., the gas dew point was 69.5 ° C. As the power generation characteristics, a battery open voltage of 96 V was obtained at no load when no current was output to the outside. Moreover, when the internal resistance of the whole laminated battery at this time was measured, it was about 45 mΩ.

The battery of Embodiment 3 was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 85%, an oxygen utilization rate of 50%, and a current density of 0.7 A / cm ² , and the time change of the output characteristics was measured. Starting and stopping were repeated every day, and starting and stopping was performed 600 times in about one year. As a result, it was confirmed that the characteristics of the battery of the third embodiment were improved from those of the first and second embodiments, and the battery output of about 14 kW (62V-224A) was maintained for a total of 10,000 hours or more.

(Embodiment 4)
FIG. 4 is a configuration diagram of a polymer electrolyte fuel cell power generator for explaining Embodiment 4 of the present invention.

  In the fourth embodiment, in addition to the configuration of the third embodiment, as shown in FIG. 4, the cooling water temperature control is configured to achieve both responsiveness and stability. A cooling water temperature adjusting tank 29 is provided in parallel with the tank 10. In this example, the capacity of the cooling water temperature adjustment tank 29 is 20 liters, and the temperature is adjusted to 70 ° C. The cooling water low temperature tank 11 and the cooling water high temperature tank 10 are used by adjusting the mixing ratio when the cell temperature is varied, and when the power generation is desired to stabilize the cell temperature to a constant value, the adjustment valve 27 and the adjustment valve 28 are provided. By switching, the cooling water circulates in the cooling water temperature control tank 29. Other configurations are the same as those in the first and third embodiments.

  When the fuel cell is generated by the polymer electrolyte fuel cell and the fuel cell power generator of Embodiment 4 having the above-described configuration, as in Embodiments 1 to 3, first, the fuel cell is held at 70 ° C. The hydrogen gas 2 humidified and heated to a dew point of 70 ° C. was supplied, and the air 1 humidified and heated to a dew point of 70 ° C. was supplied to the other electrode side.

  The cell temperature was controlled to 70.0 ° C. and the gas dew point was 69.5 ° C. As the power generation characteristics, a battery open voltage of 96 V was obtained at no load when no current was output to the outside. Further, when the internal resistance of the entire laminated battery at this time was measured, it was about 45 mΩ.

The fuel cell of Embodiment 4 was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 85%, an oxygen utilization rate of 50%, and a current density of 0.7 A / cm ² , and the change in output characteristics with time was measured. Starting and stopping were repeated every day, and starting and stopping was performed 600 times in about one year. As a result, it was confirmed that the characteristics of the fuel cell of Embodiment 4 were improved from those of Embodiments 1 and 2, and the battery output of about 14 kW (62V-224A) was maintained over a cumulative period of 10,000 hours.

(Embodiment 5)
FIG. 5 is a block diagram of a polymer electrolyte fuel cell power generator for explaining Embodiment 5 of the present invention.

  In the fifth embodiment, as shown in FIG. 5, the temperature of the air humidification tank 30 is adjusted to 80 ° C. using a 70 liter capacity, and the temperature is adjusted to 80 ° C. using the air 32 as a dry gas. The temperature of the hydrogen gas humidification tank 31 was adjusted to 80 ° C. using a 20 liter capacity, and the temperature was adjusted to 80 ° C. using the hydrogen gas 33 as a dry gas.

  The cathode humidifying gas mixing proportional valve 34 as the oxidizing gas mixing means and the anode humidifying gas mixing proportional valve 35 as the fuel gas mixing means measure the cell outlet cooling water temperature sensor 14 with the dew point to be set as the cell temperature. The mixture ratio is adjusted to the PID calculated by the calculation device 15 so that the dew point corresponds to the temperature. Other configurations are the same as those in the first embodiment.

  When the fuel cell is caused to generate power by the polymer electrolyte fuel cell and the fuel cell power generator of Embodiment 5 having the above-described configuration, as in Embodiments 1 to 4, first, the fuel cell is held at 70 ° C. Hydrogen gas humidified and heated to a dew point of 70 ° C. was supplied, and air humidified and heated to a dew point of 70 ° C. was supplied to the other electrode side.

  While the cell temperature was controlled at 70.5 ° C, the gas dew point was 68 ° C. As the power generation characteristics, a battery open voltage of 96 V was obtained at no load when no current was output to the outside. Moreover, when the internal resistance of the whole laminated battery at this time was measured, it was about 45 mΩ.

The fuel cell of Embodiment 5 was subjected to a continuous power generation test under the conditions of a fuel utilization rate of 85%, an oxygen utilization rate of 50%, and a current density of 0.7 A / cm ² , and the change in output characteristics with time was measured. Starting and stopping was repeated every day, and starting and stopping was performed 300 times in about one year. As a result, it was confirmed that the fuel cell of the fifth embodiment maintained a battery output of about 14 kW (62V-224A) over a total of 8000 hours as in the first embodiment.

  The present invention is applied to a power generator of a polymer electrolyte fuel cell, and is effective as a humidification control method for an apparatus for controlling environmental temperature and relative humidity.

1 is a configuration diagram of a polymer electrolyte fuel cell power generator for explaining Embodiment 1 of the present invention. Configuration diagram of polymer electrolyte fuel cell power generator for explaining Embodiment 2 of the present invention Configuration diagram of polymer electrolyte fuel cell power generator for explaining Embodiment 3 of the present invention Configuration diagram of polymer electrolyte fuel cell power generator for explaining Embodiment 4 of the present invention Configuration diagram of polymer electrolyte fuel cell power generator for explaining Embodiment 5 of the present invention Configuration diagram of conventional fuel cell power generator The figure showing the relationship between the gas pressure and gas dew point in Embodiment 1. The figure showing the relationship between the cell temperature and gas dew point at the time of fuel cell starting in the conventional fuel cell power generator The figure showing the relationship between the cell temperature at the time of fuel cell starting in embodiment, and a gas dew point

Explanation of symbols

1,32 Air 2,33 Hydrogen gas 3,30 Air humidification tank 4,31 Hydrogen gas humidification tank 5 Air pressure regulating valve 6 Hydrogen gas pressure regulating valve 7 Polymer electrolyte membrane 8a Cathode 8b Anode 9 Cell cooling circuit 10 High temperature of cooling water Tank 11 Cooling water low temperature tank 12 Cooling water mixing valve 13 Cell inlet cooling water temperature sensor 14 Cell outlet cooling water temperature sensor 15 Calculation means 16, 34 Cathodic humidification gas mixing proportional valve 17, 35 Anode humidifying gas mixing proportional valve 18, 19 Air High temperature humidification tanks 20, 21 Hydrogen gas high temperature humidification tank 22 Air heater 23 Hydrogen gas heater 24 Temperature control device 25 Air dew point sensor 26 Hydrogen gas dew point sensors 27, 28 Control valve 29 Cooling water temperature control tank

Claims (10)

  Fuel gas pressure adjusting means for adjusting the pressure of the fuel gas supplied to the fuel cell, oxidizing gas pressure adjusting means for adjusting the pressure of the supplied oxidizing gas, and a pressure command value to the fuel gas pressure adjusting means for the fuel cell And calculating means for calculating the pressure command value to the oxidizing gas pressure adjusting means from the fuel cell temperature measured by the temperature measuring means. A fuel cell power generator characterized by the above.   A fuel gas pressure adjusting means is installed between a fuel gas humidifying means for humidifying the fuel gas and a fuel gas introduction port provided in the fuel cell, and provided in the fuel cell and the oxidizing gas humidifying means for humidifying the oxidizing gas. 2. The fuel cell power generator according to claim 1, wherein an oxidizing gas pressure adjusting means is installed between the oxidizing gas inlet and the oxidizing gas inlet.   A fuel gas heating means is installed between the fuel gas pressure adjusting means and the fuel gas inlet, and an oxidizing gas heating means is installed between the oxidizing gas pressure adjusting means and the oxidizing gas inlet. The fuel cell power generator according to claim 1 or 2.   A fuel gas dew point measuring means is installed at least before or after the fuel gas heating means, and a command value to the fuel gas pressure adjusting means is calculated and output so as to follow the dew point measured by the fuel gas dew point measuring means. In addition, an oxidizing gas dew point measuring means is installed at least before or after the oxidizing gas heating means, and a command value to the oxidizing gas pressure adjusting means is calculated and output so as to follow the dew point measured by the oxidizing gas dew point measuring means. 4. The fuel cell power generator according to claim 3, further comprising a dew point control means.   A first fuel gas humidifying means and a second fuel gas humidifying means for diverting and humidifying a fuel gas supplied to the fuel cell, and installed after the first fuel gas humidifying means and the second fuel gas humidifying means. The fuel gas mixing means for mixing the humidified fuel gas output from the first fuel gas humidifying means and the humidified fuel gas output from the second fuel gas humidifying means, and the oxidant gas supplied to the fuel cell is divided. The first oxidizing gas humidifying means and the first oxidizing gas humidifying means, and the first oxidizing gas humidifying means installed after the first oxidizing gas humidifying means and the second oxidizing gas humidifying means. An oxidant gas mixing means for mixing the humidified oxidant gas output from the second oxidant gas humidified gas output from the second oxidant gas humidifying means, and a mixture ratio command value for the fuel gas mixing means. And calculating means for calculating from the fuel cell temperature measured by the temperature measuring means and calculating the mixture ratio command value to the oxidizing gas mixing means from the fuel cell temperature measured by the temperature measuring means. A fuel cell power generator.   The humidifying temperature of the first fuel gas humidifying means is set higher than the fuel cell operating temperature, the humidifying temperature of the second fuel gas humidifying means is set lower than the fuel cell operating temperature, and the first oxidizing gas 6. The fuel cell power generation according to claim 5, wherein the humidifying temperature of the humidifying means is set higher than the fuel cell operating temperature, and the humidifying temperature of the second oxidizing gas humidifying means is set lower than the fuel cell operating temperature. apparatus.   6. The fuel gas heating means is installed between the fuel gas mixing means and the fuel gas inlet, and the oxidizing gas heating means is installed between the oxidizing gas mixing means and the oxidizing gas inlet. Or 6. The fuel cell power generator according to 6.   A fuel gas dew point measuring means is installed at least before or after the fuel gas heating means, and a command value to the fuel gas mixing means is calculated and output so as to follow the dew point measured by the fuel gas dew point measuring means. A dew point for calculating and outputting a command value to the oxidizing gas mixing means so as to follow the dew point measured by the oxidizing gas dew point measuring means by installing an oxidizing gas dew point measuring means at least before or after the oxidizing gas heating means. 8. The fuel cell power generator according to claim 7, further comprising control means.   A fuel cell using the fuel cell power generator according to any one of claims 1 to 8 as a power generation unit.   A fuel cell comprising a polymer electrolyte membrane and a cell comprising a pair of electrodes sandwiching the polymer electrolyte membrane, and a cooling circuit for cooling the cell, each having a gas dew point on the gas suction side of the pair of electrodes A fuel cell comprising a sensor for detection.

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