JP2007328976A - Fuel cell power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generator in which life of an oxidizer gas purification means is extended and which is superior in durability by installing a bypass route in an oxidizer gas purification means. <P>SOLUTION: This is the fuel cell power generator which is provided with a switching means 9 to switch a route of the oxidizer gas purification means 6 to purify the oxidizer gas and a bypass route 8 not to purify the oxidizer gas, and in which the life of the oxidizer gas purification means 6 is extended and the device can be obtained which is superior in durability since the oxidizer gas is made to be circulated into the route of the oxidizer gas purification means 6 and impurities are purified when the effect given by the impurities contained in the oxidizer gas is significant, and since the impurities are not purified and the oxidizer gas is switched to be circulated into the bypass route 8 when the effect is small. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation device that is intended to suppress deterioration due to impurities contained in an oxidant gas or to improve durability.

  The configuration and operation of a conventional general solid polymer electrolyte fuel cell will be described with reference to FIG. In FIG. 6, reference numeral 1 denotes a solid polymer electrolyte made of perfluorocarbon sulfonic acid having hydrogen ion conductivity. An anode 21 and a cathode 22 are formed as a pair of electrodes on both surfaces of the electrolyte 1. The anode 21 and the cathode 22 have a catalyst layer made of a mixture of a catalyst in which a noble metal such as platinum is supported on porous carbon and a polymer electrolyte having hydrogen ion conductivity, and air permeability and electronic conductivity laminated on the catalyst layer. A gas diffusion layer having a property is provided. A pair of gaskets for preventing gas mixing and leakage are disposed around the anode 21 and the cathode 22, a fuel gas containing at least hydrogen is supplied to and discharged from the anode 21, and an oxidizing agent containing at least oxygen is supplied to the cathode 22. It is sandwiched between a pair of conductive separator plates 31 and 32 having gas flow paths for supplying and discharging gas.

  A stack in which a plurality of single cells having the above configuration are stacked is referred to as a stack, and the single cell or stack is collectively referred to as a fuel cell.

  On the anode 21 side of the fuel cell is a fuel processor 4 that generates hydrogen from a raw material gas such as methane, and supplies the fuel gas.

  Further, an oxidant gas supply means 5 for taking in oxygen from the atmosphere is provided on the cathode 22 side of the fuel cell, and oxidant gas is supplied. Oxidant gas is a general term for gas containing at least oxygen (or capable of supplying oxygen), and air (air) is an example.

  When a fuel gas and an oxidant gas are supplied to the anode 21 and the cathode 22, respectively, and a load is connected, hydrogen contained in the fuel gas supplied to the anode 21 emits electrons at the interface between the anode 21 and the electrolyte 1 to generate hydrogen ions. (Chemical formula 1)

  The hydrogen ions move to the cathode 22 through the electrolyte 1, receive electrons at the interface between the cathode 22 and the electrolyte 1, react with oxygen contained in the oxidant gas supplied to the cathode 22, and generate water ( 2).

  The total reaction is shown in (Chemical Formula 3).

  At this time, the flow of electrons flowing through the load can be used as direct current electric energy. Moreover, since a series of reactions are exothermic reactions, the reaction heat can be used as thermal energy.

  Next, the configuration and operation of a general fuel cell power generator including the fuel processing unit 4 will be described. First, a raw material gas containing a hydrocarbon such as methane is supplied to a desulfurization section, and a sulfur compound contained in an odorant is adsorbed and removed (desulfurization). Then, it is reformed by the fuel processing unit 4 to become a fuel gas containing hydrogen, which is supplied to the anode 21 of the fuel cell. The fuel processing unit 4 includes a reformer that reforms methane and the like, a CO converter that transforms carbon monoxide (CO) generated by the reforming reaction, and a CO remover that further oxidizes and removes CO. .

  When methane is used as the source gas, in the reformer, the reaction shown in (Chemical Formula 4) occurs with water vapor, and about 10% of CO is generated together with hydrogen.

  Thereafter, the generated CO is oxidized to carbon dioxide by a CO converter as shown in (Chemical Formula 5) and reduced to about 5000 ppm. Since the downstream CO remover oxidizes not only CO but also hydrogen of the fuel gas, it is necessary to reduce the CO concentration as much as possible with the CO converter.

  Further, the remaining CO is oxidized by reacting with oxygen contained in the air in the CO remover as shown in (Chemical Formula 6), and its concentration is reduced to about 10 ppm or less.

  The overall reaction formula is shown in (Chemical Formula 7).

  In the operating temperature range of the fuel cell, platinum contained in the anode 21 is poisoned even with a slight amount of CO of 10 ppm, and its catalytic activity deteriorates. Therefore, a catalyst having CO resistance such as platinum-ruthenium is usually used for the anode 21. It is done. However, even in a CO-resistant catalyst, the CO concentration contained in the fuel gas must be suppressed to at least 10 ppm or less.

  Further, if impurities exist in the oxidant gas, the output voltage of the fuel cell is lowered due to the impurities. For example, when organic compounds such as nitrogen oxides and unburned hydrocarbons contained in the exhaust gas of automobiles are mixed in the oxidant gas as impurities, the main reaction between hydrogen and oxygen generated on platinum at the cathode 22 is inhibited. Therefore, the output voltage of the fuel cell 5 decreases. Further, when sulfur compounds such as sulfur dioxide contained in exhaust gas discharged from automobiles and factories and hydrogen sulfide contained in a lot of hot springs are mixed as impurities, platinum contained in the cathode 22 is poisoned, and the catalyst Activity will deteriorate. Moreover, when ammonia which is offensive odor is mixed, the acidic electrolyte 1 is neutralized and the ionic conductivity of the electrolyte 1 is lowered. Therefore, it is necessary to remove impurities that adversely affect the characteristics of the fuel cell 5 contained in the oxidant gas.

Conventionally, for example, an oxidant gas purification unit that removes ammonia in the oxidant gas is provided, and ammonia in the oxidant gas is removed by the oxidant gas purification unit (see Patent Document 1). Thereby, even if ammonia is contained in oxidant gas, since it is removed, it can suppress that an output voltage falls by ammonia.
JP-A-6-84537

  However, since the conventional oxidant gas purification means adsorbs and removes impurities contained in the gas using an adsorbent such as activated carbon or zeolite, it is necessary to frequently replace the oxidant gas purification means that has passed through the adsorption. there were.

  The present invention solves the above-described conventional problems, and provides a fuel cell power generator having excellent durability by extending the life of the oxidant gas purification means by providing a bypass path in the oxidant gas purification means. With the goal.

  In order to solve the above-described conventional problems, the fuel cell power generation device of the present invention includes a switching unit that switches between a path of an oxidant gas purification unit that purifies the oxidant gas and a bypass path that does not purify the oxidant gas. is there.

  As a result, when the influence of the impurities contained in the oxidant gas is large, the oxidant gas is circulated through the path of the oxidant gas purification means to purify the impurities, and when the influence is small, the impurities are purified. Therefore, since the oxidant gas is switched to the bypass path and circulated, the life of the oxidant gas purification means is extended, and a fuel cell power generator excellent in durability can be obtained.

  As described above, according to the fuel cell power generator of the present invention, the impurities are purified only when the influence of the impurities contained in the oxidant gas is large. Therefore, the life of the oxidant gas purification means is extended and the durability is improved. An excellent fuel cell power generator can be provided.

The invention according to claim 1 is a gas that supplies and discharges an electrolyte, a pair of electrodes sandwiching the electrolyte, and a fuel gas containing at least hydrogen to one of the electrodes, and an oxidant gas containing at least oxygen to the other. A fuel cell comprising at least one cell having a pair of separator plates having flow paths; an oxidant gas supply means for supplying the oxidant gas; an oxidant gas purification means for purifying the oxidant gas; Included in the oxidant gas, comprising a bypass path for supplying oxidant gas to the fuel cell without passing through the oxidant gas purification means, and a switching means for switching between the path of the oxidant gas purification means and the bypass path When the effect of the generated impurities is large, the oxidant gas is circulated through the path of the oxidant gas purification means to purify the impurities. When the influence is small, the impurities are not purified and the oxidation is performed. Because be distributed switching the gas to the bypass passage, it extends the life of the oxidizing gas purification unit, it is possible to obtain excellent fuel cell system durability.

  The invention described in claim 2 includes voltage detection means for detecting the voltage of the fuel cell, and when the voltage detected by the voltage detection means is lower than a lower limit threshold, the switching means is provided in the path of the oxidant gas purification means. By switching for a certain time, the oxidant gas purification means purifies impurities only when the voltage drops and exceeds the threshold, and after a certain time passes, it switches to the bypass path again. Can be minimized.

  The invention described in claim 3 includes generated power command means for determining the generated power of the fuel cell, and sets a lower limit threshold of the voltage of the fuel cell for switching the switching means to the generated power command value output by the generated power command means. By decreasing with increase, the voltage of the fuel cell decreases with increase in generated power, and even if impurities are mixed in oxidant gas in that voltage state, the lower threshold value according to the generated power Therefore, even if the generated power fluctuates, the voltage drop caused by impurities can be suppressed.

  Since the pressure loss of the path of the oxidant gas purification means and the pressure loss of the bypass path are made the same in the invention according to the fourth aspect, the air volume can be changed without changing the capacity value such as the rotational speed of the oxidant gas supply means. Can be switched from the bypass path to the path of the oxidant gas purification means while keeping the constant.

  According to the fifth aspect of the present invention, since the capacity value of the oxidant gas supply means when supplying the oxidant gas to the path of the oxidant gas purification means is made larger than when supplying the oxidant gas to the bypass path, The structure does not need to have a high pressure loss, and the structure is simple and economical.

  The invention according to claim 6 determines the replacement timing of the oxidant gas purification means from the volume of the oxidant gas circulated through the oxidant gas purification means, so that the oxidant gas supplied by the oxidant gas supply means From the volume and the time when the switching means switches to the path of the oxidant gas purification means, the usage amount of the oxidant gas purification means can be estimated, and the user can be prompted for the replacement time.

  The oxidant gas purification means includes an alkaline impurity removal filter that removes alkaline impurities, an acidic impurity removal filter that removes acidic impurities, and a dust removal filter that removes dust. Remove alkaline impurities such as ammonia and trimethylamine that may exist in the air to be taken in with an alkaline impurity removal filter, and remove acidic impurities such as hydrogen sulfide, sulfur dioxide, nitrogen dioxide, hydrogen chloride, and hydrogen fluoride. In addition, particulate impurities such as dust contained in the atmosphere are removed with a dust filter, preventing the poisoning of the catalyst and the decrease in ionic conductivity caused by these impurities mixed in the oxidant gas. And a decrease in battery voltage can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a fuel cell power generator according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a membrane-shaped solid polymer electrolyte made of a perfluorocarbon sulfonic acid polymer having hydrogen ion conductivity. A pair of electrodes, an anode 21 and a cathode 22 are formed on both surfaces of the electrolyte 1. When the electrolyte 1 takes in moisture, the hydrogen ions of the sulfonic acid groups in the electrolyte 1 are dissociated to become charge carriers, and the electrolyte 1 passes through a reverse micelle structure formed by aggregation of several sulfonic acid groups. Shows hydrogen ion conductivity. Since the electrical conductivity of the electrolyte 1 decreases when the water content decreases, a method of preventing the drying of the electrolyte 1 film by supplying the gas with humidification was adopted.

  The anode 21 and the cathode 22 have a catalyst layer made of a mixture of a catalyst in which a noble metal such as platinum is supported on porous carbon and a polymer electrolyte having hydrogen ion conductivity, and air permeability and electronic conductivity laminated on the catalyst layer. It consists of a gas diffusion layer having properties. For the anode 21, an alloy catalyst such as platinum-ruthenium having CO resistance was used. Moreover, carbon paper or carbon cloth subjected to water repellent treatment was used for the gas diffusion layer.

  A pair of gaskets for preventing gas mixing and leakage are arranged around the anode 21 and the cathode 22, respectively, and further, gas flow paths for supplying and discharging fuel gas and oxidant gas to the anode 21 and the cathode 22, respectively. The pair of conductive separator plates 31 and 32 having the pair was sandwiched. The voltage generated by the single cell configured as described above is about 0.75 V, and a plurality of single cells corresponding to the required voltage can be stacked in series to form a fuel cell with a desired output. it can.

  In addition, current collector plates, insulating plates, and end plates were disposed at both ends of the separator plates 31 and 32 and fixed with fastening rods. Then, a load and voltage detection means 7 are connected to the current collector plate so that the voltage of the fuel cell when a constant current flows can be detected.

  Further, the oxidant gas was taken in from the oxidant gas supply means 5 such as a fan, a pump and an air blower from the atmosphere, and supplied to the cathode 22 of the fuel cell at a predetermined flow rate by the flow rate control means. The oxidant gas supply means 5 depends on the pressure loss of the supply path, and by controlling the capacity values of the oxidant gas supply means 5 such as voltage, rotation speed, frequency, etc., even if the pressure loss fluctuates, a constant oxidation is achieved. An agent gas can be supplied.

  Also, a plurality of paths for sending the oxidant gas to the cathode 22 are provided. One path includes an oxidant gas purification means 6 for removing impurities contained in the oxidant gas, and the other path purifies the oxidant gas. Instead, the bypass path 8 is made to pass through as it is. The path of the oxidant gas purification means 6 and the bypass path 8 can be switched by the switching means 9.

  With this configuration, when the influence of the impurities contained in the oxidant gas is large, the oxidant gas is circulated through the path of the oxidant gas purification means 6 to purify the impurities. When the influence is small, the impurities are removed. Since the oxidant gas is switched to the bypass path and circulated without being purified, the life of the oxidant gas purification means 6 is extended, and a fuel cell power generator having excellent durability can be obtained.

  Further, the pressure loss of the path of the oxidant gas purification means 6 and the pressure of the bypass path 8 are configured to be the same. Therefore, the path of the oxidant gas can be switched without changing the air volume while keeping the capacity value such as the rotation speed of the oxidant gas supply means 5 constant.

The switching means 9 is configured to be able to switch the path of the oxidant gas according to the fuel cell voltage detected by the voltage detection means 7. With this configuration, when the voltage detected by the voltage detection means 7 exceeds the threshold value, the switching means 9 is switched to the path of the oxidant gas purification means 5 for a certain period of time, so that the oxidant is reduced only when the voltage drops and exceeds the threshold value. Impurities are purified by the gas purifying means 5 and, after a predetermined time has elapsed, switching to the bypass path 8 is performed again, so that the frequency of use of the oxidant gas purifying means 5 can be minimized.

  In the atmosphere, there are various kinds such as ammonia, hydrogen sulfide, sulfur dioxide, nitrogen dioxide contained in exhaust gas from automobiles, hydrogen chloride, hydrogen fluoride discharged from factories, etc. in the bad smell generated from garbage, toilets, hospitals, etc. May contain various impurities. Since the fuel cell power generator is installed in a general household, a store, a factory, etc., it must withstand even in such an environment.

  The oxidant gas purification means 6 includes a coarse filter 61 that removes particulate matter such as dust contained in the atmosphere and particulate matter such as dust generated from the oxidant gas supply means 5, hydrogen sulfide, and sulfur dioxide. , An acidic impurity removing filter 62 that removes acidic impurities such as nitrogen dioxide, hydrogen chloride, and hydrogen fluoride; and an alkaline impurity removing filter 63 that removes alkaline impurities such as ammonia and trimethylamine that may be contained in the atmosphere. And dust removal filter 64 that removes particulate matter such as dust contained in the atmosphere and particulate matter such as dust generated from acidic impurity removal filter 62 and alkaline impurity removal filter 63 in the previous stage. Is housed in a housing and is piped to guide clean air to the cathode 22. To have.

  In addition, when the acidic impurity removal filter 62 and the alkaline impurity removal filter 63 come into contact with each other, the respective filters deteriorate. Therefore, a spacer was arranged to avoid contact.

  Further, a buffer material was provided around the acidic impurity removal filter 62, the alkaline impurity removal filter 63, and the dust filter 64, and the buffer material was housed in the housing via the buffer material. Thereby, airtightness improves, the leak of the impurity which arises because the oxidant gas to process flows around from the filter periphery can be prevented, and the removal performance of various filters can be improved.

  The oxidant gas taken in from the atmosphere first passes through the coarse filter 61, then passes through the acidic impurity removal filter 62 and the spacer, passes through the alkaline impurity removal filter 63, and finally passes through the dust removal filter 64. Reduce the concentration of impurities.

  As the coarse filter 61, a fiber made of polypropylene or the like was charged and then woven into a nonwoven fabric. The coarse filter 61 removes not only dust in which each of the charged fibers is contained in the oxidant gas, but also dust and particulate matter generated from the oxidant gas supply means 5 disposed in the preceding stage. . Moreover, not only the removal performance of the acidic impurity removal filter 62 and the alkaline impurity removal filter 63 is maintained, but the load of the dust removal filter 64 is reduced, so that the life of the dust removal filter 64 can be extended.

  The acidic impurity removal filter 62 was obtained by using calcium hydroxide as an alkali that absorbs acidic impurities, kneading activated carbon and a curing agent, granulating, and molding into a honeycomb type. Calcined gypsum was used as the curing agent. When calcined gypsum is mixed with water, it becomes calcium sulfate and hardens. Calcium hydroxide reacts with acidic impurities such as nitrogen dioxide and sulfur dioxide as shown in (Chemical Formula 8) and (Chemical Formula 9), respectively, to fix calcium nitrate and calcium sulfate on the acidic impurity removal filter 62, respectively. Chemisorbed.

  Therefore, instead of simply adsorbing, impurities and alkali are reacted and fixed on the filter, so there is no desorption depending on the concentration or temperature, and the desorbed high-concentration impurities are mixed into the fuel cell. Can be prevented from deteriorating. Moreover, since porous activated carbon is used, organic solvents, such as toluene, methyl ethyl ketone, and trichloroethylene, can also be adsorbed, and the deterioration of battery performance due to these impurities can be suppressed. In addition, the reaction area can be increased by using a honeycomb structure. Further, pressure loss due to the acidic impurity removal filter 62 of the oxidant gas to be introduced can be reduced and clogging can be suppressed, so that the load on the oxidant gas supply means 5 is not affected and the power generation efficiency remains high. Can be held.

  The alkaline impurity removal filter 63 was obtained by impregnating a fibrous activated carbon sheet with a phosphoric acid solution adjusted to a constant concentration as an absorbent for alkaline impurities, separating and drying, and further processing the sheet into a corrugated type. Phosphoric acid is fixed on the surface of the activated carbon fiber, and ammonium phosphate generated by reacting with an alkaline impurity such as ammonia as shown in (Chemical Formula 10) is fixed on the surface of the activated carbon fiber and chemically adsorbed.

  Therefore, it is not simply adsorbed, but the impurities and the adhering substance are reacted and fixed on the alkaline impurity removing filter 63, so that they are not desorbed depending on the concentration and temperature, and the desorbed impurities are mixed into the fuel cell. It is possible to prevent the battery performance from deteriorating. Moreover, since porous activated carbon is used, organic solvents, such as toluene, methyl ethyl ketone, and trichloroethylene, can also be adsorbed, and the deterioration of battery performance due to these impurities can be suppressed. Further, by using fibrous activated carbon, not only can the weight be reduced, but the degree of freedom in shape and size can be increased, and breakage such as cracks and cracks can be eliminated. In addition, the reaction area can be increased by using a corrugated structure. In addition, the pressure loss of the oxidant gas introduced by the alkaline impurity removal filter 63 can be reduced and clogging is suppressed, so that the load of the oxidant gas supply means 5 is not affected and the power generation efficiency remains high. Can be held.

  The dust removal filter 64 was manufactured by charging a fiber made of polypropylene or the like, and then increasing the basis weight of the coarse filter 61 to make a woven nonwoven fabric into a pleated shape and fixing it to a frame. Each of the electrostatically charged fibers attracts and adsorbs micro dust floating in the air by the action of Coulomb force or induced force, so that particulate matter such as dust in the atmosphere and acidic impurity removal filter 62 in the previous stage And particulate matter such as dust generated from the alkaline impurity removal filter 63 itself can be efficiently removed.

In addition, a configuration is provided that includes a generated power command means (not shown) for determining the generated power of the fuel cell, and outputs the generated power command value to the fuel cell according to the required power. When the generated power command means determines the generated power, fuel gas and oxidant gas in amounts necessary for flowing a current corresponding to the generated power to the fuel cell are supplied to the fuel cell. The voltage of the fuel cell depends on the current density of the flowing current. As the current density increases, the polarization increases and the voltage of the fuel cell decreases.

  FIG. 2 shows the relationship between the generated power and the average cell voltage of the fuel cell power generator configured as described above. As shown in FIG. 2, it can be seen that during normal power generation, the voltage of the fuel cell decreases as the generated power increases. On the other hand, when impurities (contamination) such as nitrogen oxide are mixed in the oxidant gas, the voltage decreases as indicated by the broken line unless the oxidant gas purification means 6 purifies the impurities. In the embodiment of the present invention, a lower limit threshold value for the impurity of the voltage of the fuel cell is provided, and when the voltage drops due to the impurity and exceeds the threshold value, the switching means 9 is switched to the path of the oxidant gas purification means 6. The voltage drop is eliminated, and the voltage can be restored to the normal state. In addition, as long as the voltage of the fuel cell does not reach the threshold value, the oxidant gas is supplied through the bypass path and the oxidant gas purification unit 6 is not consumed, so that the life of the oxidant gas purification unit 6 can be extended.

  Further, as shown in FIG. 2, the threshold value for the impurity of the voltage of the fuel cell is decreased as the generated power command value is increased and switched to the path of the oxidant gas purification means 6 at a threshold value corresponding to each generated power. Even if it fluctuates, the voltage drop due to impurities can be suppressed following the change.

  FIG. 3 shows a flowchart of the implementation of the present invention when impurities are included in the oxidant gas. In a state where power generation is started, first, a generated power command value that is currently generated is determined (step 1). Then, the threshold value of the lower limit voltage when impurities corresponding to the generated power at that time are mixed is determined (step 2). At this point, the oxidant gas is supplied to the cathode 22 via the bypass path 8. After starting the power generation, the voltage detection means 7 detects the voltage of the fuel cell and determines whether or not the voltage detected by the voltage detection means 7 has reached the threshold value (step 3). If the voltage has reached the threshold value, the voltage may have dropped due to the mixing of impurities, so the switching means 9 is switched to the path of the oxidant gas purification means 6 to purify the oxidant gas and supply it to the cathode 22 ( Step 4). The oxidant gas purification means 6 purifies the oxidant gas and waits for a predetermined time to elapse (step 5). When the predetermined time has elapsed, the switching means 9 is returned to the bypass path and the process is terminated (step 6). Again, returning to the beginning, the voltage of the fuel cell is detected.

  FIG. 4 shows an example of the change over time of the lowered voltage when impurities by the fuel cell power generator in the embodiment of the present invention are mixed in the oxidant gas. Oxidant gas was circulated through the bypass path 8 and the threshold for the drop voltage was set to 5 mV. In order to simulate impurities in the atmosphere, the test gas concentration of nitrogen dioxide was varied and supplied. When the concentration of nitrogen dioxide fluctuates and the drop voltage of the fuel cell fluctuates, and the voltage detection means 7 detects that the drop voltage has become 5 mV or more, the switching means 9 is switched and the oxidant gas is changed to the oxidant gas purification means. 6 was supplied to the cathode 22 through six paths. When the predetermined time has elapsed, the path is switched to the bypass path again. At that time, when the reduced voltage still exceeds the threshold, the path is switched to the path of the oxidant gas purification means 6 again. The drop voltage when the oxidant gas was supplied via the path of the oxidant gas purification means 6 was almost zero. Therefore, it has been confirmed that the oxidant gas purification means 6 of the present invention is sufficiently purifying the oxidant gas. The estimated voltage drop when not switching to the oxidant gas purification means 6 is indicated by a broken line. As a result of this test, the time during which the oxidant gas flowed through the path of the oxidant gas purification means 6 was only 25% of the power generation time. Therefore, it has been found that the life of the oxidant gas purification means 6 is extended about four times as compared with the case where power is generated by purifying the oxidant gas continuously via the oxidant gas purification means 6.

  Therefore, according to the fuel cell power generator of the embodiment of the present invention, the impurities are purified only when the influence of the impurities contained in the oxidant gas is large. Therefore, the life of the oxidant gas purification means 6 is extended and the durability is improved. It is possible to provide a fuel cell power generator having excellent performance.

(Embodiment 2)
FIG. 5 is a schematic configuration diagram of the fuel cell power generator according to the second embodiment of the present invention. The difference from the first embodiment is that an oxidant gas purification means 6 and a bypass path 8 are arranged in front of the oxidant gas supply means 5. The rest is the same as in the first embodiment, and a detailed description thereof is omitted.

  In FIG. 5, by arranging the oxidant gas purification means 6 and the bypass path 8 on the suction side of the oxidant gas supply means 5, the configuration of the bypass path 8 can be simplified or omitted, and the apparatus can be downsized. Cost can be reduced.

  Further, since the capacity value such as the number of revolutions of the oxidant gas supply means 5 when supplying the oxidant gas via the path of the oxidant gas purification means 6 is made larger than that through the bypass path 8, the bypass path Therefore, the structure is simple and economical.

  The fuel cell power generator of the present invention has an effect of suppressing deterioration due to impurities or improving durability, and is useful for a power generator and a device using a polymer solid electrolyte membrane.

  Moreover, it is useful for a stationary fuel cell cogeneration system installed outdoors where impurities such as bad odor and exhaust gas may exist.

1 is a schematic configuration diagram of a fuel cell power generator according to a first embodiment of the present invention. Battery voltage characteristics of the device Flow chart showing operation when voltage drop of the device is detected Characteristic diagram showing the transition of voltage drop when impurities in the device are mixed Schematic configuration diagram of a fuel cell power generator according to a second embodiment of the present invention Schematic configuration diagram of a conventional fuel cell power generator

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte 5 Oxidant gas supply means 6 Oxidant gas purification means 7 Voltage detection means 8 Bypass path 9 Switching means 21 Electrode (anode)
22 electrode (cathode)
31, 32 Separator plate 61, 64 Dust removal filter 62 Acid impurity removal filter 63 Alkaline impurity removal filter

Claims (7)

An electrolyte, a pair of electrodes sandwiching the electrolyte, and a pair of separator plates having a gas flow path for supplying and discharging a fuel gas containing at least hydrogen to one of the electrodes and supplying and discharging an oxidizing gas containing at least oxygen to the other of the electrodes; A fuel cell comprising at least one cell having: an oxidant gas supply means for supplying the oxidant gas; an oxidant gas purification means for purifying the oxidant gas; and the oxidant gas purification means. A fuel cell power generator comprising: a bypass path for supplying an oxidant gas to the fuel cell; and a switching means for switching between the path of the oxidant gas purification means and the bypass path. The voltage detection means for detecting the voltage of the fuel cell is provided, and when the voltage detected by the voltage detection means becomes lower than a lower limit threshold, the switching means is switched to the path of the oxidant gas purification means for a certain time. Fuel cell power generator. The power generation command means for determining the power generated by the fuel cell is provided, and the lower limit threshold of the voltage of the fuel cell for switching the switching means is decreased as the power generation command value output by the power generation command means increases. Fuel cell power generator. The fuel cell power generator according to claim 1, wherein the pressure loss in the path of the oxidant gas purification means and the pressure loss in the bypass path are the same. 2. The fuel cell power generator according to claim 1, wherein the capacity value of the oxidant gas supply means when supplying the oxidant gas to the path of the oxidant gas purification means is larger than that when supplying the oxidant gas to the bypass path. 2. The fuel cell power generator according to claim 1, wherein the replacement timing of the oxidant gas purification means is determined from the volume of the oxidant gas circulated through the oxidant gas purification means. 2. The fuel cell power generator according to claim 1, wherein the oxidant gas purification means includes an alkaline impurity removal filter that removes alkaline impurities, an acidic impurity removal filter that removes acidic impurities, and a dust removal filter that removes dust. 3.