JP4590829B2 - Fuel cell system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a fuel cell in which deterioration due to start / stop is reduced or durability is improved.
[0002]
[Prior art]
  A general configuration of a conventional fuel cell will be described using a polymer electrolyte membrane type. A fuel cell obtains electric energy and heat energy mainly from hydrogen and oxygen. Due to the catalytic action of Pt or the like, the reaction represented by (Formula 1) occurs on the fuel electrode side, and the reaction represented by (Formula 2) occurs on the oxygen-containing electrode. The total reaction is represented by (Formula 3). In addition to Pt, a mixture or alloy with Ru is used on the fuel electrode side to prevent deterioration due to carbon monoxide. By these actions, the fuel cell reacts with hydrogen and oxygen, and only water is produced as a reaction product. A major feature is that no substances that affect the environment are discharged. However, since it is not necessary to move until the time when electricity or heat energy is not needed, there is a need for a “start / stop type” operation that starts when necessary and stops when not needed. Several methods have been considered as methods of starting and stopping.
[0003]
  H₂→ 2H⁺+ 2e^-                (Formula 1)
  1 / 2O₂+ 2H⁺+ 2e^-→ H₂O (Formula 2)
  H₂+ 1 / 2O₂→ H₂O (Formula 3)
  When stopping, keep the supply of oxygen-containing gas and fuel gas and leave it as it is, or stop and store in a humidified inert gas in order to keep the ion exchange membrane, which is an electrolyte membrane, in the water retaining state even during storage The method is shown (for example, refer patent document 1). Moreover, in order to prevent oxidation of the oxygen electrode or adhesion of impurities, a method is shown in which power generation is performed in a state where supply of the oxygen-containing gas is stopped and oxygen consumption operation is performed to improve durability (for example, Patent Document 2). reference).
[0004]
[Patent Document 1]
  JP-A-6-251788
[Patent Document 2]
  JP 2002-93448 A
[0005]
[Problems to be solved by the invention]
  However, when starting and stopping, there is a problem that the oxygen-containing gas side electrode is oxidized or adsorbed with impurities, and the generated voltage is lowered. In addition, in the method of stopping the supply of the oxygen-containing gas and the fuel gas at the time of the stop, even if the operation of the fuel cell and the system is stopped, the voltage is generated in the fuel cell as long as the gas remains. In particular, the circuit is in an open circuit state because no current is taken during the stop. In an open circuit state exceeding 0.9 V, there is a problem that the reaction area due to particle enlargement, which is called elution and sintering, of the oxygen-containing electrode is reduced. When the gas is completely reacted, the voltage of the fuel cell decreases, but the gaseous oxygen and hydrogen react to become liquid water, so in the sealed state where the volume decreases, the inside of the fuel cell becomes negative pressure and a hole is formed in the electrolyte membrane. There is a risk of opening. If it is not sealed, there is a possibility that external air enters the fuel cell as the gas decreases, humidity changes and impurities may be mixed in, and the performance of the fuel cell is degraded. In the stop / storage method in which humidified inert gas is enclosed to keep the ion exchange membrane, which is an electrolyte membrane, in the water-retaining state during storage, the temperature of the fuel cell decreases during the stop and is given for humidification. Since water vapor condenses into a liquid, the volume is reduced, the inside of the fuel cell becomes negative pressure, and there is a problem that there is a risk of opening a hole in an electrolyte membrane or the like. In addition, for the purpose of preventing the oxidation of the oxygen electrode or adhesion of impurities and preventing the decrease in power generation voltage due to the start and stop, power generation is performed with the supply of oxygen-containing gas stopped, and oxygen consumption operation is performed to improve durability. However, since the electrode potential on the oxygen-containing gas side due to power generation is not uniform, there is a problem that the effect of preventing the voltage drop is not uniform.
[0006]
  The present invention solves the above-mentioned conventional problems, purging the fuel gas with an inert gas to the fuel cell, and storing the inert gas and the oxygen-containing gas while remaining in the fuel cell. Even in an open circuit state, the potential does not become high, and deterioration at the time of stopping can be reduced. In addition, since the inert gas is not humidified as much as during operation, even if the temperature of the fuel cell decreases, the dew condensation is small and the degree of decompression is small. An object is to realize a fuel cell system that is highly durable even when it is stopped.Also,By using the raw material gas cleaned in the gas cleaning section as an inert gas for the fuel cell, it is easier to achieve a fuel cell system that reduces deterioration due to start and stop more easily.2The purpose ofThe
[0007]
  In order to solve the above-described conventional problems, the fuel cell system of the present invention stops the supply of the fuel gas when stopped, purges the fuel gas inside the fuel cell with an inert gas to the fuel cell, and deactivates the fuel cell system. Gas and oxygen-containing gas are stopped while being stored inside the fuel cell.Here, as the inert gas, the raw material gas cleaned in the gas cleaning section is used.
[0008]
  As a result, a high potential is not obtained even in an open circuit state at the time of stop, and deterioration at the time of stop can be reduced. In addition, since the inert gas is not humidified as much as during operation, even if the temperature of the fuel cell decreases, the dew condensation is small and the degree of decompression is small. Even if the operation is stopped, a highly durable fuel cell system can be realized.Further, no special preparation such as a nitrogen cylinder is required, and a fuel cell system in which deterioration due to start / stop is easily reduced can be realized.
[0009]
  The invention according to claim 1 is a gas flow in which an electrolyte membrane, a pair of electrodes sandwiching the electrolyte membrane, a fuel gas containing at least hydrogen is supplied to and discharged from one of the electrodes, and an oxygen-containing gas is supplied to and discharged from the other A fuel cell including a pair of separators having a path, a fuel generator that generates fuel gas to be supplied from the raw material gas to the fuel cell, a gas cleaning unit that removes components that adversely affect the fuel cell from the raw material gas, In a fuel cell system having a power circuit unit that extracts power from the fuel cell and a control unit that controls the gas and the power circuit unit, the supply of the fuel gas is stopped when the fuel cell is stopped, and the fuel gas inside the fuel cell Purging with inert gas to the fuel cellAndFlow oxygen-containing gasAndStop inert gas and oxygen-containing gas inside the fuel cell. Here, as the inert gas, the raw material gas cleaned in the gas cleaning section is used. thisIf the high voltage is maintained even when the open circuit is stoppedCan reduce the deterioration at the time of stopping.In addition, since the inert gas is not humidified as much as during operation, even if the temperature of the fuel cell decreases, the dew condensation is small and the degree of decompression is small. Even if the operation is stopped, a highly durable fuel cell system can be realized. Further, no special preparation such as a nitrogen cylinder is required, and a fuel cell system in which deterioration due to start / stop is easily reduced can be realized.
[0011]
  Hereinafter, the fuel cell according to the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.
[0012]
【Example】
  Example 1
  FIG. 1 shows a basic configuration of a polymer electrolyte membrane fuel cell among the fuel cells in Example 1 of the present invention. A fuel cell is one that causes a fuel gas such as hydrogen and an oxygen-containing gas such as air to react electrochemically with a gas diffusion electrode, and generates electricity and heat simultaneously. Reference numeral 1 denotes an electrolyte membrane, which is used by a polymer electrolyte membrane or the like that selectively transports hydrogen ions. A catalytic reaction layer 2 mainly composed of carbon powder carrying a platinum-based metal catalyst is disposed in close contact with both surfaces of the electrolyte membrane 1. In this catalytic reaction layer, the reactions shown in (Formula 1) and (Formula 2) occur. A fuel gas containing at least hydrogen (hereinafter referred to as anode gas) undergoes the reaction shown in (Equation 1) (hereinafter referred to as anode reaction), and the hydrogen ions moved through the electrolyte membrane 1 are converted into oxygen-containing gas (hereinafter referred to as anode gas). Water is generated by the reaction shown in (Formula 2) in the catalytic reaction layer 2 (hereinafter referred to as cathode reaction) and the catalyst reaction layer 2, and electricity and heat are generated at this time. The side in which fuel gas such as hydrogen is involved is called an anode, and a is added in the figure, the side in which oxygen-containing gas such as air is involved is called a cathode, and c is shown in the figure. Further, a diffusion layer 3 having both gas permeability and conductivity is disposed on the outer surface of the catalyst reaction layer 2 in close contact therewith. The diffusion layer 3 and the catalytic reaction layer 2 constitute an electrode 4. Reference numeral 5 denotes an electrode electrolyte assembly (hereinafter referred to as MEA), which is formed by the electrode 4 and the electrolyte membrane 1. The MEA 5 is used for mechanically fixing the MEA 5 and electrically connecting adjacent MEAs 5 to each other, supplying a reaction gas to the electrodes, and carrying away a gas generated by the reaction and excess gas. A pair of conductive separators 7 in which the gas flow path 6 is formed on the surface in contact with the MEA 5 are arranged. A basic fuel cell (hereinafter referred to as a cell) is formed by the electrolyte membrane 1, a pair of catalytic reaction layers 2, a pair of diffusion layers 3, a pair of electrodes 4, and a pair of separators 7. The separator 7 of the adjacent cell is in contact with the separator 7 on the surface opposite to the MEA 5. A cooling water passage 8 is provided on the side where the separators 7 are in contact with each other, and the cooling water 9 flows there. The cooling water 9 moves heat through the separator 7 so as to adjust the temperature of the MEA 5. 10 is an MEA gasket that seals the MEA 5 and the separator 7, and 11 is a separator gasket that seals the separators 7 to each other.
[0013]
  The electrolyte membrane 1 has a fixed charge, and hydrogen ions exist as counter ions of the fixed charge. The electrolyte membrane 1 is required to have a function of selectively permeating hydrogen ions. For this purpose, the electrolyte membrane 1 needs to retain moisture. This is because when the electrolyte membrane 1 contains moisture, the fixed charge fixed in the electrolyte membrane 1 is ionized, and hydrogen, which is a counter ion of the fixed charge, is ionized and can move.
[0014]
  FIG. 2 is a stack of cells and is called a stack. Since the voltage of the fuel cell is usually as low as about 0.75 v, a plurality of cells are stacked in series so as to obtain a high voltage. Reference numerals 21a and 21c denote current collecting plates for taking out current from the stack to the outside, and 22a and 22c are insulating plates for electrically insulating the cell from the outside. Reference numerals 23a and 23c denote end plates that fasten and mechanically hold a stack of stacked cells.
[0015]
  FIG. 3 is a configuration diagram of the fuel cell system. Reference numeral 31 denotes an outer casing of the fuel cell system. A gas cleaning unit 32 removes substances that adversely affect the fuel cell from the fuel gas, and guides the fuel gas from the source gas pipe 33. A valve 34 controls the flow of the raw material gas. A fuel generator 35 generates a fuel gas containing at least hydrogen from the raw material gas. The raw material gas is guided to the fuel generator 35 through 36 raw material gas pipes. Reference numeral 38 denotes a stack, which is a fuel cell and a stack whose details are shown in FIGS. A fuel gas pipe 37 guides the fuel gas from the fuel generator 35 to the stack 38. A valve 49 controls the flow of the fuel gas to the stack 38. A blower 39 guides oxygen-containing gas to the stack 38 through 40 intake pipes. An exhaust pipe 42 discharges the oxygen-containing gas discharged from the stack 38 to the outside of the fuel cell system. 41 is a humidifier. Since the fuel cell requires moisture, the oxygen-containing gas flowing into the stack 38 through the intake pipe 40 is humidified here. The fuel gas not used in the stack 38 flows again into the fuel generator 35 through the 48 off-gas pipes. The gas from the off-gas pipe 48 is used for combustion or the like, and is used for an endothermic reaction or the like for generating a fuel gas from the raw material gas. A valve 51 controls off gas flowing from the stack 38 to the fuel generator 35. Reference numeral 43 denotes a power circuit unit that extracts power from the fuel cell stack 38, and reference numeral 44 denotes a control unit that controls the gas, the power circuit unit, and the like. Reference numeral 45 denotes a pump that allows water to flow from the cooling water inlet pipe 46 to the water path of the fuel cell stack 38. The water that has flowed through the fuel cell 38 is carried to the outside through 47 cooling water outlet pipes. By flowing water through the stack 38 of the fuel cell, the generated heat can be used outside the fuel cell system while maintaining the heated stack 38 at a constant temperature. The fuel cell system includes a stack 38 composed of fuel cells, a gas cleaning unit 32, a fuel generator 35, a power circuit unit 43, and a control unit 44.
[0016]
  The basic operation will be described. In FIG. 3, the valve 34 is opened, and the source gas flows from the source gas pipe 33 into the gas cleaning unit 32. A hydrocarbon gas such as natural gas or propane gas can be used as the raw material gas. In this embodiment, 13A, which is a mixed gas of methane, ethane, propane and butane gas, was used. As the gas cleaning part 32, a member for removing gas odorant such as TBM (tertiary butyl mercaptan), DMS (dimethyl sulfide), THT (tetrahydrothiofin) is used. This is because sulfur compounds such as odorants are adsorbed on the catalyst of the fuel cell to become a catalyst poison and inhibit the reaction. In the fuel generator 35, hydrogen is generated by the reaction shown in (Equation 6).
[0017]
  CH_Three+ H₂O → 3H₂+ CO (−203.0 KJ / mol) (Formula 6)
  Here, a fuel gas containing hydrogen and moisture is created and flows into the fuel cell stack 38 via the fuel gas pipe 37. The oxygen-containing gas passes through the humidifier 41 by the blower 39 and then flows into the stack 38. The exhaust gas of oxygen-containing gas is discharged to the outside through the exhaust pipe 42. As the humidifier 41, one that flows an oxygen-containing gas into warm water or one that blows water into the oxygen-containing gas can be used. In this embodiment, a total heat exchange type was used. This moves water and heat in the exhaust gas into the oxygen-containing gas that is a raw material carried from the intake pipe 40 when passing through the humidifier 41. The cooling water flows from the cooling water inlet pipe 46 to the water path of the fuel cell stack 38 from the pump 45, and then the water is carried to the outside from the cooling water outlet pipe 47. Although not shown in the drawing, the cooling water inlet pipe 45 and the cooling water outlet are usually provided with a hot water heater or the like in the transfer pipe 47. The heat generated in the fuel cell stack 38 is taken out and can be used for hot water supply or the like. The operation of the fuel cell in the stack 38 will be described with reference to FIG. An oxygen-containing gas such as air is flowed through the gas flow path 6c, and a fuel gas containing hydrogen is flowed through the gas flow path 6a. Hydrogen in the fuel gas diffuses through the diffusion layer 3a and reaches the catalytic reaction layer 2a. In the catalytic reaction layer 2a, hydrogen is divided into hydrogen ions and electrons. The electrons are moved to the cathode side through an external circuit. Hydrogen ions permeate the electrolyte membrane 1 and move to the cathode side to reach the catalytic reaction layer 2c. Oxygen in an oxygen-containing gas such as air diffuses through the diffusion layer 3c and reaches the catalytic reaction layer 2c. In the catalyst reaction layer 2c, oxygen reacts with electrons to form oxygen ions, and the oxygen ions react with hydrogen ions to generate water. That is, oxygen-containing gas and fuel gas react around MEA 5 to generate water, and electrons flow. Further, heat is generated during the reaction, and the temperature of MEA 5 rises. Therefore, the heat generated in the reaction is carried out by water by flowing water or the like through the cooling water paths 8a and 8c. That is, heat and current (electricity) are generated. At this time, it is important to control the humidity of the introduced gas and the amount of water generated by the reaction. When there is little moisture, the electrolyte membrane 1 is dried and the ionization of the fixed charges is reduced, so that the movement of hydrogen is reduced, so that the generation of heat and electricity is reduced. On the other hand, when there is too much water, water accumulates around the MEA 5 or around the catalytic reaction layer 2, and the gas supply is inhibited and the reaction is suppressed, thereby reducing the generation of heat and electricity (hereinafter, This state is called flatting.)
[0018]
  The operation after reacting in the fuel cell will be described with reference to FIG. Exhaust gas in which no oxygen-containing gas is used passes heat and moisture to the oxygen-containing gas sent from the blower 39 via the humidifier 41 and is then discharged to the outside. The off gas that has not been used for the fuel gas flows again into the fuel generator 35 through the 48 off gas pipes. The gas from the off gas pipe 48 is used for combustion in the fuel generator 35. Since the reaction for generating the fuel gas from the raw material gas is an endothermic reaction as shown in (Formula 6), it is used as heat necessary for the reaction. The power circuit 43 serves to draw DC power from the stack 38 after the fuel cell starts generating power. The controller 44 controls the other parts of the fuel cell system so as to keep the control optimal. In this embodiment, in FIG. 1, the MEA 5 was created as follows.
[0019]
  Carbon powder acetylene black (Denka Black manufactured by Denki Kagaku Kogyo Co., Ltd., particle size 35 nm) is mixed with an aqueous dispersion of polytetrafluoroethylene (PtFE) (D1 manufactured by Daikin Kogyo Co., Ltd.) and dried. A water repellent ink containing 20% by weight of PtFE was prepared. This ink is applied and impregnated on carbon paper (TGPH060H manufactured by Toray Industries, Inc.) serving as a base material for the gas diffusion layer, and heat-treated at 300 ° C. using a hot air drier to form a gas diffusion layer (about 200 μm ) Was formed.
[0020]
  Meanwhile, 66 parts by weight of a catalyst body (50% by weight Pt) obtained by loading a Pt catalyst on Ketjen Black (Ketjen Black EC, Ketjen Black International Co., Ltd., particle size 30 nm), which is carbon powder. Is mixed with 33 parts by weight (polymer dry weight) of perfluorocarbon sulfonic acid ionomer (5% by weight Nafion dispersion manufactured by Aldrich, USA), which is a hydrogen ion conductive material and binder, and the resulting mixture is molded. Thus, a catalyst layer (10 to 20 μm) was formed.
[0021]
  The gas diffusion layer and the catalyst layer obtained as described above were bonded to both surfaces of a polymer electrolyte membrane (Nafion 112 membrane manufactured by DuPont, USA) to produce MEA5.
[0022]
  Next, a rubber gasket plate was joined to the outer peripheral part of the electrolyte membrane 1 of the MEA 5 produced as described above to form manifold holes for circulating cooling water, fuel gas, and oxidant gas.
[0023]
  On the other hand, a conductive separator 7 made of a graphite plate impregnated with phenol resin, having an outer dimension of 20 cm × 32 cm × 1.3 mm and a gas channel and a cooling water channel having a depth of 0.5 mm is used. It was.
[0024]
  The operation of this embodimentFuel cell system of FIG.I will explain it.The source gas was city gas 13A, and the oxygen-containing gas was air. The temperature of the fuel cell was 70 ° C., the fuel gas utilization rate (Uf) was 70%, and the oxygen utilization rate (Uo) was 40%. The fuel gas and air were humidified to have dew points of 65 ° C and 70 ° C, respectively. A current was taken out from the power circuit unit 43. Current is 0.2A / cm per apparent area of electrode.²It adjusted so that it might become. Although not shown in the cooling water inlet pipe 46 and the cooling water outlet pipe 47, the temperature of the water in the cooling water inlet pipe 46 to which the hot water storage tank is attached is 70 ° C., and the temperature of the water in the cooling water outlet pipe 47. The pump 45 was adjusted to 75 ° C. The other conditions were as follows.
[0025]
  As an embodiment of the present inventionIn the operation condition A, the steady operation process was performed, and then the stop process 1 was performed. The current from the stack is taken out by the power circuit unit 43. When the voltage of a typical single cell of the stack 38 falls below 0.5V, the current taking is stopped, and when the voltage exceeds 0.6, the current is taken out again. Control was performed by the control unit 44 as described above. In the stop step 1, first, the supply of fuel gas from the fuel generator 35 to the stack 38 was stopped, and the raw material gas was poured. The raw material gas used here is obtained by removing substances that adversely affect the fuel cell, such as sulfur compounds such as odorants, nitrogen compounds such as ammonia and amine substances, and carbon monoxide in the gas cleaning unit 32. The fuel gas pushed out of the stack 38 by the raw material gas from the stack is returned to the fuel generator 35 from the off-gas pipe 48, and the fuel gas in the stack 38 is replaced with the raw material gas. Next, stop process 2 was performed. In the stop step 2, the blower 39 is stopped to stop the supply of air to the stack 38, the valve 49 and the valve 51 are closed, and the source gas is sealed in the stack 38. Although the blower 39 is stopped, the air is connected to the outside through the intake pipe 40 or the exhaust pipe 42. That is, inside the stack 38, air opened to the outside and the sealed source gas are collected. Further, the pump 45 is stopped and the movement of the cooling water from the outside is eliminated. Next, it becomes stop process 3. In the stop process 3, the fuel cell system does not particularly operate, but the temperature of the fuel processor 35 and the fuel cell stack 38 that are at a high temperature gradually decreases, and finally becomes the same as the external temperature. Next, it becomes the starting process 1. In the starting process 1, the raw material gas is flowed to the fuel processor 35 and the hydrogen gas is contained so that the concentration of the non-fuel substance such as carbon monoxide is reduced to a certain level or less. The stack 38 may raise the temperature by operating the pump 45 and circulating water having a temperature higher than that of the stack 38. Next, the startup process 2 is entered. In the starting process 2, the blower 39 is operated to send air into the stack 38, and the valve 49 and the valve 51 are opened to allow fuel gas to flow through the stack 38. This causes a reaction between power generation and heat generation in the fuel cell stack 38. After the fuel and current are controlled and the conditions for the steady operation process are reached, the operation is performed as a steady operation process.
[0026]
  FIG. 4 shows a typical single cell voltage and a pressure difference of the anode with respect to the cathode (hereinafter referred to as a differential pressure) when the normal operation is resumed after stopping and starting from the normal operation under the present operation conditions.
[0027]
  As the first comparison conditionMost of the operating conditions D are the same as the operating conditions A, but the differences are as follows.
[0028]
  In the stop process 1, after the supply of the fuel gas to the stack 38 is stopped, air, not the raw material gas, is flowed into the stack 38. Therefore, when the valve 49 and the valve 51 are closed in the stop step 2, that is, inside the stack 38, the air released to the outside and the sealed air are accumulated.
[0029]
  FIG. 7 shows the voltage of a typical single cell and the differential pressure of the anode with respect to the cathode when the stationary operation is performed again after stopping and starting from the stationary operation under the operating condition D as the first comparison condition.
[0030]
  As the second comparison conditionMost of the operating conditions E are the same as the operating conditions A, but the differences are as follows.
[0031]
  In the stop step 1, after the supply of the fuel gas to the stack 38 is stopped, the raw material gas that does not pass through the gas cleaning unit 32, that is, has not been cleaned, flows into the stack 38. Therefore, when the valve 49 and the valve 51 are closed in the stop step 2, that is, inside the stack 38, uncleaned city gas opened to the outside and sealed air are accumulated.
[0032]
  FIG. 8 shows the voltage of a typical single cell and the differential pressure of the anode with respect to the cathode when the steady operation is performed again after stopping and starting from the steady operation under the operation condition E as the second comparison condition.
[0033]
  FIG.Figure 7 and FigureAs you can see in 8As an embodiment of the present inventionOperating conditionsAThen, even when stopping and starting, there is almost no voltage difference in the steady operation process before and after stopping and starting. For it,As the first comparison conditionUnder operating condition D, the voltage is greatly reduced, and by inserting air instead of fuel gasPower generationIt can be seen that the performance is greatly reduced. This is because the anode electrode is deteriorated by oxidation or the like. In particular, the reaction catalyst layer containing ruthenium becomes ruthenium oxide or the like and may be eluted.As the second comparison conditionUnder operating condition E, the voltage after stopping / starting is greatly reduced. City gas contains odorants and the like, which greatly impedes the power generation of the fuel cell, but the purified gas can be treated as an inert gas to the same extent as nitrogen. Nitrogen requires special equipment, but purified city gas is very convenient because it can be supplied to the system without any special equipment.
[0034]
【The invention's effect】
  As aboveFuel cell system of the present inventionAccording toWithout special preparation such as nitrogen cylinders, easily reduce deterioration due to start and stop,Since it does not become a high voltage even in the open circuit state at the time of stop, it suppresses deterioration during start and stop and has a long lifeButIt can be realized.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a partial structure of a unit cell of a polymer electrolyte membrane fuel cell in Example 1 of the present invention.
FIG. 2 is a schematic view showing the structure of a stack in which polymer electrolyte membrane fuel cells are stacked in Example 1 of the present invention.
FIG. 3 is a configuration diagram showing a polymer electrolyte membrane fuel cell system in Example 1 of the present invention.
FIG. 4 is a time chart showing voltage and differential pressure under operating condition A in Experimental Example 1 in Example 1 of the present invention.
FIG. 5 is a time chart showing voltage and differential pressure under operating condition B in Example 1 of the experiment.
FIG. 6 is a time chart showing voltage and differential pressure under operating condition C in Example 1 of the experiment.
7 is a time chart showing voltage and differential pressure according to operating condition D in Example 1 of the experiment. FIG.
FIG. 8 is a time chart showing voltage and differential pressure under operating condition E in Experimental Example 1
FIG. 9 is a time chart showing voltage and anode / cathode electrode potential under operating condition J in Experimental Example 2 in Example 1 of the present invention.
FIG. 10 is a time chart showing the voltage under the operating condition K and the electrode potentials of the anode and the cathode in Example 2 of the experiment.
FIG. 11 is a time chart showing the voltage under the operating condition L and the electrode potentials of the anode and cathode in Example 2 of the experiment.
FIG. 12 is a time chart showing the voltage under the operating condition M and the electrode potentials of the anode and cathode in Experimental Example 2
FIG. 13 is a time chart showing the voltage under the operating condition N and the electrode potentials of the anode and the cathode in Example 2 of the experiment.
14 is a time chart showing the voltage under the operating condition O and the electrode potentials of the anode and the cathode in Example 2 of the experiment. FIG.
FIG. 15 is a diagram showing the relationship between the control voltage and the increase in voltage before and after stop / start in Experimental Example 3 in Example 1 of the present invention.
FIG. 16 is a graph showing the relationship between the sulfur concentration of the raw material gas and the deterioration of the generated voltage in Experimental Example 4 in Example 1 of the present invention.
[Explanation of symbols]
1 Electrolyte membrane
2a Catalytic reaction layer (anode side)
2c Catalytic reaction layer (cathode side)
3a Diffusion layer (anode side)
3c Diffusion layer (cathode side)
7a Separator (Anode side)
7c Separator (cathode side)
32 Gas Cleaner
35 Fuel generator
43 Power circuit
44 Control unit

Claims (1)

An electrolyte membrane; a pair of electrodes sandwiching the electrolyte membrane; and a pair of separators 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 oxygen-containing gas to the other , a fuel cell equipped with a,
A fuel generator for generating the fuel gas supplied to the fuel cell from the raw material gas,
A gas cleaning unit for removing components adversely affecting the fuel cell from the raw material gas,
A power circuit unit for extracting power from the fuel cell;
A control unit for controlling at least gas and the power circuit unit,
In a fuel cell system having
When it stops the fuel cell stops the supply of the fuel gas, the fuel cell inside the fuel gas is purged with inert gas to said fuel cell, flowing the oxygen-containing gas, the inert gas the oxygen-containing gas is stopped while reservoir within the fuel cell and,
The inert gas is the source gas cleaned by the gas cleaning unit.
A fuel cell system characterized by that.

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