JP2017183158A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system capable of suppressing a decline in electric power supply stability of a fuel cell, while reducing a flooding phenomenon.SOLUTION: During normal operation, a determination is made whether or not flooding phenomenon is occurring in a cathode electrode, and when a determination is made that flooding phenomenon is occurring, oxidizer supply amount increase control for controlling an oxidizer supply amount adjustment section 34 to increase the supply amount of oxidizer is performed. Furthermore, flow path opening reduction control 35 for controlling a flow path opening adjustment section 35 so as to reduce the flow path opening of a pipeline F4, while keeping the same supply amount of oxidizer as that during normal operation, is performed simultaneously with the oxidizer supply amount increase control, thus transiting the operation state of the fuel cell system from normal operation to flooding phenomenon reduction operation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

Conventionally known as a generator is a fuel cell.
In general, there are a plurality of types of fuel cells, and the fuel cells are classified mainly by differences in active materials and electrolytes.
Hereinafter, among a plurality of types of fuel cells, methanol and an oxidant (oxygen or air; hereinafter collectively referred to as an oxidant) as an active material, and a solid polymer electrolyte as an electrolyte are used. A methanol fuel cell will be described as an example.

Generally, a direct methanol fuel cell includes a membrane-electrode assembly (MEA) as a power generator.
The membrane electrode assembly includes an anode catalyst layer and an anode gas diffusion layer laminated on the anode catalyst layer as an anode electrode, a cathode gas diffusion layer laminated on the cathode catalyst layer and the cathode catalyst layer as a cathode electrode, and an anode And an electrolyte membrane disposed between the catalyst layer and the cathode catalyst layer.

Here, the role of each component of the membrane electrode assembly is as follows, and the direct methanol fuel cell can obtain power from the membrane electrode assembly by the following reaction generated by this role. .
That is, the anode catalyst layer causes an oxidation reaction between methanol and water contained in an aqueous methanol solution supplied from an anode gas diffusion layer described later, as shown in the following formula (1), and generates protons and electrons. Plays a role to generate.
The anode catalyst layer plays a role of supplying protons to the electrolyte membrane and supplying electrons to the cathode catalyst layer described later.
CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ (1)
The anode gas diffusion layer plays a role of uniformly supplying an aqueous methanol solution supplied from the outside of the membrane electrode assembly to the anode catalyst layer.
Further, the electrolyte membrane supplies protons supplied from the anode catalyst layer to the cathode catalyst layer, which will be described later, while suppressing an unreacted methanol aqueous solution and electrons from being supplied directly to the cathode catalyst layer in the anode catalyst layer. Playing a role.
Further, the cathode catalyst layer is reduced between the oxidant supplied from the cathode gas diffusion layer, the proton supplied from the electrolyte membrane, and the electrons supplied from the anode catalyst layer as shown in the following formula (2). It plays a role in causing a reaction.
3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O (2)
Further, the cathode gas diffusion layer plays a role of uniformly supplying an oxidant supplied from an oxidant supply container described later to a cathode catalyst layer described later.
By the above oxidation reaction and reduction reaction, a current flows between the membrane electrode assemblies, and electric power can be obtained from the membrane electrode assemblies.
Note that the water generated in the cathode catalyst layer by the reduction reaction permeates the electrolyte membrane and is not directly supplied to the anode catalyst layer. Therefore, hereinafter, only the cathode electrode in which water is likely to stay will be described, and the description of the anode electrode will be omitted.

Here, in the cathode electrode, a cathode separator is provided on the upper surface of the cathode gas diffusion layer, and the cathode channel is formed by a closed space between the groove formed on the surface of the cathode separator and the surface of the cathode gas diffusion layer. Is formed. For this reason, the oxidizing agent supplied from the outside of the membrane electrode assembly flows and flows through the cathode channel.
On the oxidant supply side, the cathode channel is connected to an oxidant supply container existing outside the membrane electrode assembly via an external channel.
On the oxidant discharge side, the cathode channel is connected to the exhaust channel, and the end of the exhaust channel is open to the outside air.
For this reason, the oxidizing agent is supplied from the oxidizing agent supply container to the cathode passage and the cathode gas diffusion layer via the external passage, and then from the cathode passage to the exhaust passage (hereinafter referred to as the cathode passage and the external passage and The exhaust flow path is also simply referred to as a flow path) and is discharged to the outside of the fuel cell.

In general, in the cathode catalyst layer, water is generated by the reduction reaction as shown in the above formula (2), and this water is eventually applied to the inside of the cathode gas diffusion layer, the surface of the cathode gas diffusion layer in contact with the cathode channel, or the like. Moving. In addition, this water is usually discharged to the outside of the fuel cell together with the oxidant supplied to the cathode flow path. A part of this water is diffused in the cathode gas diffusion layer in contact with the inside of the cathode gas diffusion layer and the cathode flow path. It remains as water droplets on the surface of the layer.
For this reason, when water is excessively generated in the cathode catalyst layer, the excessively generated water (hereinafter referred to as excessively generated water) becomes relatively large water droplets, and the inside of the cathode gas diffusion layer or the cathode flow. It remains on the surface of the cathode gas diffusion layer in contact with the path.
As a result, there arises a so-called flooding phenomenon in which the oxidant that normally flows or diffuses in the cathode catalyst layer and the cathode gas diffusion layer is likely to be inhibited by the excessively generated water. As a result, the efficiency of the above-described reduction reaction is reduced, resulting in a problem that the power value of the fuel cell is reduced.
Here, for the sake of explanation, the cathode electrode of the direct methanol fuel cell is taken as an example of the location where the above flooding phenomenon occurs. However, since excessive water is generated at either the anode electrode or the cathode electrode, If present, the flooding phenomenon can occur in other types of fuel cells such as hydrogen fuel cells and hydrazine fuel cells.

As a means for reducing the flooding phenomenon, in the past, when the occurrence of the flooding phenomenon was detected, the flow rate of the oxidant gas supplied to the cathode of the fuel cell was increased to increase the amount of excess from the fuel cell. A fuel cell system that discharges moisture is known (Patent Document 1).
For this reason, in the normal operation before the occurrence of the flooding phenomenon, when the occurrence of the flooding phenomenon is detected, the flow rate of the oxidant gas supplied to the cathode is increased. The pressure in the road increases.
As a result, the amount of excess water remaining on the inside of the cathode, the surface of the cathode in contact with the cathode channel, and the like by this increased pressure increases.
As a result, the flooding phenomenon can be reduced.

JP 2007-48507 A

However, in the conventional fuel cell system, when the flow rate of the oxidant gas is increased in order to reduce the flooding phenomenon, the reduction reaction in the cathode catalyst layer is further promoted. Since the amount further increases, the amount of excess water produced tends to increase.
For this reason, since the flow path of the oxidant gas is likely to be blocked by the excessively generated water, the excessively generated water and the oxidant gas are liable to stay in the flow path, so that the discharge amount of the excessively generated water and the oxidant gas is reduced. Changes over time.
As a result, the pressure in the flow path of the oxidant gas becomes gradually less stable, and the fluctuation of the power value in the fuel cell increases, so that there is a problem that the stable power supply in the fuel cell decreases.

  In view of the above problems, an object of the present invention is to provide a fuel cell system capable of suppressing a decrease in stable supply of electric power in a fuel cell while reducing a flooding phenomenon.

  A fuel cell system according to the present invention includes a fuel cell, an oxidant supply unit that supplies an oxidant to a cathode electrode of the fuel cell, and an oxidizer that is provided in the oxidant supply unit and adjusts the supply amount of the oxidant. An oxidant supply amount adjustment unit, connected to the cathode electrode, provided at least in the oxidant discharge flow channel unit for discharging the oxidant, and provided in the oxidant discharge flow channel unit; A fuel cell system comprising: a channel opening degree adjusting unit that adjusts a path opening degree; and a control unit that is connected to the cathode electrode and controls the oxidant supply amount adjusting unit and the channel opening degree adjusting unit. The control unit determines whether or not a flooding phenomenon has occurred at the cathode electrode during normal operation of the fuel cell. If it is determined that the flooding phenomenon has occurred, the supply amount of the oxidant is determined. Increase The oxidant supply amount adjustment unit for controlling the oxidant supply amount adjustment unit is further performed, and further, while maintaining the same amount as the supply amount of the oxidant during the normal operation, The flow rate opening degree decreasing control for controlling the flow rate opening degree adjustment unit is performed simultaneously with the oxidant supply amount increase control so that the flow rate degree of the flow rate decreases, and the operation state of the fuel cell system is changed from the normal operation to the flooding phenomenon It is characterized by shifting to a flooding phenomenon reduction operation that reduces the flooding.

  Further, in the fuel cell system according to the present invention, after a predetermined time has elapsed since the oxidant supply amount increase control and the flow path opening degree decrease control have been performed, the control unit includes the oxidant supply amount and the Oxidant supply amount reduction control for controlling the oxidant supply amount adjustment unit so that the supply amount of the oxidant is decreased until the degree of openness of the oxidant discharge flow channel unit becomes substantially the same as that during the normal operation. And the flow rate opening degree increasing control for controlling the flow rate opening degree adjustment unit so that the flow rate opening degree of the oxidant discharge flow path portion is increased, and the operation state of the fuel cell system is changed from the flooding phenomenon reducing operation. You may make it transfer to the said normal driving | operation.

  Further, in the fuel cell system according to the present invention, the controller controls the oxidant supply amount decrease control and the flow path opening while maintaining the same amount as the oxidant supply amount during the flooding phenomenon reducing operation. The degree increase control may be performed simultaneously.

  Further, in the fuel cell system according to the present invention, after a predetermined time has elapsed after performing the oxidant supply amount increase control and the flow path opening degree decrease control, the control unit stops the supply of the oxidant. As described above, the oxidant supply stop control for controlling the oxidant supply amount adjusting unit and the channel openness increase for controlling the channel openness adjusting unit so that the channel openness of the oxidant discharge channel unit is increased. The supply of the oxidant until the supply amount of the oxidant and the degree of openness of the oxidant discharge flow path unit become approximately the same as those during the normal operation when a predetermined time has elapsed after performing the control. The oxidant supply amount adjustment control for controlling the oxidant supply amount adjustment unit so that the amount increases, and the flow path opening degree adjustment unit is controlled so that the degree of openness of the oxidant discharge flow passage unit decreases. Control the degree of openness of the flow path to control the operating state of the fuel cell system From serial flooding reducing operation may be shifted to the normal operation.

  Further, in the fuel cell system according to the present invention, the control unit simultaneously performs the oxidant supply stop control and the flow path opening degree increase control, or performs the oxidant supply stop control more than the flow path opening degree increase control. It may be done later.

  Further, in the fuel cell system according to the present invention, the controller controls the oxidant supply amount increase control and the flow path opening while maintaining the same amount as the oxidant supply amount during the flooding phenomenon reducing operation. The degree reduction control may be performed simultaneously.

  Further, in the fuel cell system according to the present invention, the controller opens the flow path opening degree adjustment unit until the flow path open degree of the oxidant discharge flow path unit becomes maximum in the flow path open degree increase control. You may control.

  The fuel cell system according to the present invention includes a fuel cell, a gaseous fuel supply unit that supplies gaseous fuel to the anode electrode of the fuel cell, and the gaseous fuel supply unit, and adjusts the supply amount of the gaseous fuel. A fuel supply amount adjustment unit that is connected to the anode electrode, and is provided in the fuel discharge channel unit that discharges at least the gaseous fuel, and is provided in the fuel discharge channel unit, and the channel of the fuel discharge channel unit is opened A fuel cell system comprising: a channel opening degree adjusting unit that adjusts the degree; and a control unit that is connected to the anode electrode and controls the fuel supply amount adjusting unit and the channel opening degree adjusting unit. The control unit determines whether or not a flooding phenomenon has occurred at the anode electrode during normal operation of the fuel cell, and when it is determined that the flooding phenomenon has occurred, The fuel supply amount increase control for controlling the fuel supply amount adjustment unit so that the supply amount of the gaseous fuel increases while maintaining the same amount as the supply amount of the gaseous fuel, and the flow path of the fuel discharge flow path section The flow rate opening degree decreasing control for controlling the flow rate opening degree adjusting unit is simultaneously performed so that the opening degree is reduced, and the operation state of the fuel cell system is shifted from the normal operation to the flooding phenomenon reducing operation. .

  Further, in the fuel cell system according to the present invention, after a predetermined time has elapsed since the fuel supply amount increase control and the flow path opening degree decrease control have been performed, the control unit is configured to supply the gaseous fuel supply amount and the fuel. Fuel supply amount reduction control for controlling the fuel supply amount adjustment unit and the fuel discharge so that the supply amount of the gaseous fuel decreases until the degree of openness of the discharge passage portion becomes approximately the same as that during the normal operation. The flow rate opening degree increase control is performed to control the flow rate opening degree adjustment unit so that the flow rate degree of the flow path portion is increased, and the operation state of the fuel cell system is shifted from the flooding phenomenon reduction operation to the normal operation. You may let them.

  In the fuel cell system according to the present invention, the control unit maintains the fuel supply amount decrease control and the flow path opening degree while maintaining the same amount as the supply amount of the oxidant during the flooding phenomenon reduction operation. Increase control may be performed simultaneously.

According to the present invention, the controller determines whether or not the flooding phenomenon has occurred at the cathode electrode of the fuel cell, and when it is determined that the flooding phenomenon has occurred, the supply amount of the oxidant is increased. Since the oxidant supply amount increase control for controlling the oxidant supply amount adjustment unit is performed, the pressure in the oxidant discharge flow path unit increases, and as a result, the flooding phenomenon can be reduced.
In addition, when the supply amount of the oxidant discharge flow path is increased, the reduction reaction in the cathode catalyst layer is further promoted, and therefore the amount of water generated from the cathode catalyst layer further increases. The generation amount tends to increase. For this reason, since the flow path of the oxidant gas is likely to be blocked by the excessively generated water, the excessively generated water and the oxidant gas are liable to stay in the flow path, so that the discharge amount of the excessively generated water and the oxidant gas is reduced. Since it changes with time, as a result, the pressure in the flow path of the oxidizing gas gradually becomes unstable. However, in the present invention, the control unit performs the above-described oxidant supply amount increase control, and further maintains the same amount as the oxidant supply amount during normal operation before the flooding phenomenon occurs, The flow rate opening degree reduction control for controlling the flow rate opening degree adjustment unit is performed simultaneously with the oxidant supply amount increase control so that the degree of openness of the discharge flow path portion is reduced, and the operation state of the fuel cell system is changed from the normal operation. Since the operation is shifted to the flooding phenomenon reduction operation that reduces the flooding phenomenon, even if the operation is shifted to the flooding phenomenon reduction operation, the supply amount of the oxidant does not decrease from the normal operation time. The same amount can be maintained.
Therefore, in the present invention, since the supply amount of the oxidizing agent is not increased for the purpose of reducing the flooding phenomenon as in the prior art, the reduction reaction in the cathode catalyst layer accompanying the increase in the supply amount of the oxidizing agent is suppressed. The
For this reason, since the amount of water generated from the cathode catalyst layer during the flooding reduction operation can be maintained at the same level as during normal operation, it is possible to suppress the generation amount of excess generated water. It becomes possible.
As a result, the oxidant discharge flow path portion is less likely to be clogged with the excessively generated water, so that the excessively generated water and the oxidant are less likely to stay in the oxidant discharge flow path portion. It is possible to suppress changes over time in the.
Therefore, when reducing the flooding phenomenon, it becomes possible to maintain the stability of the pressure in the oxidant discharge flow path portion, so that the power value in the fuel cell is less likely to fluctuate. It becomes possible to suppress a supply fall.
As described above, according to the present invention, it is possible to realize a fuel cell system capable of suppressing a decrease in stable power supply in a fuel cell while reducing a flooding phenomenon.

1 is a block diagram showing a fuel cell system in a first embodiment of the present invention. It is sectional drawing of the fuel cell in 1st Embodiment of this invention. It is sectional drawing of the membrane electrode assembly in 1st Embodiment of this invention. It is a flowchart which shows the control procedure of the normal driving | operation and the flooding phenomenon reduction operation | movement in the control part which concerns on 1st Embodiment of this invention. It is a flowchart which shows the control procedure of the flooding phenomenon reduction operation | movement in the control part which concerns on 1st Embodiment of this invention, and normal operation. It is a block diagram which shows the fuel cell system in 2nd Embodiment of this invention. It is a flowchart which shows the control procedure of the normal driving | operation and flooding phenomenon reduction operation | movement in the control part which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the control procedure of the flooding phenomenon reduction driving | operation and normal driving | operation in the control part which concerns on 2nd Embodiment of this invention. It is the graph which showed the relationship between the electric power value of the fuel cell in the Example of this invention, and the elapsed time after starting of a fuel cell system.

(First embodiment)
FIG. 1 is a block diagram showing a fuel cell system according to the first embodiment of the present invention.

As shown in FIG. 1, a direct methanol fuel cell system 1 (hereinafter sometimes simply referred to as a fuel cell system 1) in this embodiment is a direct methanol fuel cell 2 (hereinafter simply referred to as a fuel cell 2). A fuel tank 31, a filter 32, an oxidant supply unit 33, an oxidant supply amount adjustment unit 34, a flow path opening degree adjustment unit 35, a condensing unit 36, and a circulation tank 37. The control part 38, the piping F1-F8, and the pumps G1-G3 are provided.
Hereinafter, as an explanation of each internal structure of the fuel cell system 1, after first explaining each structure of the fuel cell 2, a fuel tank 31, a filter 32, an oxidant supply unit 33, and an oxidant supply amount adjustment unit. 34, the flow path opening degree adjusting unit 35, the condensing unit 36, the circulation tank 37, the control unit 38, the pipes F1 to F8, and the pumps G1 to G3 will be described.
Next, the external fuel tank 40 and the external load 41 will be described as the description of each external structure of the fuel cell system 1.

  FIG. 2 is a cross-sectional view of the fuel cell according to the first embodiment of the present invention.

As shown in FIG. 2, the fuel cell 2 includes a membrane electrode assembly 21 including an electrolyte membrane 211, an anode catalyst layer 212, a cathode catalyst layer 213, an anode gas diffusion layer 214, and a cathode gas diffusion layer 215. An anode current collector 22, a cathode current collector 23, an anode separator 24, a cathode separator 25, a gasket 28, a gasket 29, a reinforcing layer 216A, and a reinforcing layer 216B.
Hereinafter, as the description of each structure of the fuel cell 2, first, each structure of the membrane electrode assembly 21 will be described, and then the anode current collector 22, the cathode current collector 23, the anode separator 24, the cathode separator 25, The gasket 28, the gasket 29, the reinforcing layer 216A, and the reinforcing layer 216B will be described.

  FIG. 3 is a cross-sectional view of the membrane electrode assembly in the first embodiment of the present invention.

(Structure of membrane electrode assembly)
As shown in FIG. 3, the membrane electrode assembly 21 includes an electrolyte membrane 211, an anode catalyst layer 212, a cathode catalyst layer 213, an anode gas diffusion layer 214, and a cathode gas diffusion layer 215. Yes. Here, the anode catalyst layer 212 and the anode gas diffusion layer 214 constitute an anode electrode (fuel electrode), and the cathode catalyst layer 213 and the cathode gas diffusion layer 215 constitute a cathode electrode (air electrode). The anode electrode and the cathode electrode are not limited to the above-described configuration. For example, an anode porous layer is provided between the anode catalyst layer 212 and the anode gas diffusion layer 214, and a cathode catalyst layer 213 and the cathode gas diffusion layer 215 are provided. It is good also as a structure which provided the cathode porous layer in the.

  The electrolyte membrane 211 suppresses the direct supply of a methanol aqueous solution and electrons that are unreacted in the anode catalyst layer 212 described later to the cathode catalyst layer 213, while the proton supplied from the anode catalyst layer 212 is used as the cathode catalyst described later. It plays the role of supplying to the layer 213. Therefore, the material of the electrolyte membrane 211 is not particularly limited as long as it can play the above role. For example, as an electrolyte membrane made of perfluorocarbon sulfonic acid, Nafion (trade name, registered trademark) manufactured by DuPont, USA, Aciplex (trade name, registered trademark) manufactured by Asahi Kasei Co., Ltd., or Flemion manufactured by Asahi Glass Co., Ltd. A polymer electrolyte membrane such as (trade name, registered trademark) can be used. The thickness of the electrolyte membrane 211 is not particularly limited, but is usually 25 to 250 μm.

The anode catalyst layer 212 is laminated on one main surface of the electrolyte membrane 211 in order to play the following two roles.
The first role is to generate protons and electrons by causing an oxidation reaction between methanol and water contained in an aqueous methanol solution supplied from the outside of the membrane electrode assembly 21.
The second role is to supply protons to the electrolyte membrane 211 and to supply electrons to the cathode catalyst layer 213 described later.
Here, the anode catalyst layer 212 includes, for example, an electrode catalyst, conductive carbon particles that support the electrode catalyst, and a polymer electrolyte. In addition, the specific material in each material of an electrode catalyst, electroconductive carbon particle, and a polymer electrolyte is mentioned later. The thickness of the anode catalyst layer 212 is not particularly limited, but is usually 5 to 50 μm, and is thicker than the cathode catalyst layer 213 described later from the viewpoint of further promoting the oxidation reaction of the above formula (1). Things are preferable.

  Here, the electrode catalyst in the anode catalyst layer 212 is not particularly limited, but platinum or a platinum alloy is preferably used. Platinum alloys include platinum group metals other than platinum (ruthenium, rhodium, palladium, osmium, iridium), iron, titanium, gold, silver, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium, zinc, and tin. It is preferably an alloy of one or more metals selected from the group consisting of platinum and platinum, and from the viewpoint of preventing poisoning of the platinum catalyst by carbon monoxide generated during the proton production reaction, It is particularly preferable to contain ruthenium having toxicity. The platinum alloy may contain an intermetallic compound of platinum and the metal. Furthermore, an electrode catalyst mixture obtained by mixing an electrode catalyst made of platinum and an electrode catalyst made of a platinum alloy may be used.

  Further, as the conductive carbon particles in the anode catalyst layer 212, it is preferable to use a conductive carbon material having developed pores. For example, carbon black, activated carbon, carbon fiber, carbon tube, and the like can be used. Examples of carbon black include channel black, furnace black, thermal black, and acetylene black. Activated carbon can be obtained by carbonizing and activating materials containing various carbon atoms.

  As the polymer electrolyte in the anode catalyst layer 212, the same polymer electrolyte as that constituting the electrolyte membrane 211 can be used. For example, Nafion (trade name, registered trademark) manufactured by DuPont, Inc., Aciplex (trade name, registered trademark) manufactured by Asahi Kasei Co., Ltd., Flemion (trade name, registered trademark) manufactured by Asahi Glass Co., Ltd., etc. Can be used. Note that the above polymer electrolyte covers the catalyst-supporting particles, and in order to ensure a three-dimensional hydrogen ion conduction path, the amount of the catalyst electrolyte is proportional to the mass of the catalyst-supporting particles constituting the anode catalyst layer 212. 212 is preferably included.

  The cathode catalyst layer 213 causes a reduction reaction between the oxidant supplied from the outside of the membrane electrode assembly 21, the proton supplied from the electrolyte membrane 211, and the electrons supplied from the anode catalyst layer 212. In contact with the inner surface of the second recess 4, the electrolyte membrane 211 is formed on the main surface opposite to the surface on which the anode catalyst layer 212 is provided. Here, the material composing the cathode catalyst layer 213 is basically composed of the same material as that of the anode catalyst layer 212 except for the differences described later. The thickness of the cathode catalyst layer 213 is not particularly limited, but is usually 5 to 50 μm.

  Here, the following points are mentioned as differences. That is, the mass of the polymer electrolyte contained in the cathode catalyst layer 213 is preferably 15% to 50% with respect to the mass of the cathode catalyst layer 213. Here, if the mass of the polymer electrolyte is 15% or more with respect to the mass of the cathode catalyst layer 213, sufficient hydrogen ion conductivity can be secured, and if it is 50% or less, the flooding phenomenon can be avoided. Higher battery output can be realized.

The anode gas diffusion layer 214 is laminated on the main surface of the anode catalyst layer 212 in order to play the following two roles.
The first role is to efficiently guide an aqueous methanol solution that has flowed from an anode channel 26 described later to the anode catalyst layer 212.
The second role is to supply electrons generated in the anode catalyst layer 212 to the anode current collector 22 described later.

  Here, the specific material used for the anode gas diffusion layer 214 is not particularly limited as long as it can play the above role, and an anode gas diffusion layer known in the art can be used. For example, in order to give gas permeability, it is possible to use a conductive porous substrate made of carbon fine powder having a developed structure structure, a pore former, carbon paper, carbon cloth, or the like. In order to improve drainage, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetra A material that has been subjected to a water repellent treatment after a water repellent material (polymer) typified by a fluororesin such as fluoroethylene / ethylene copolymer (ETFE) is dispersed inside the substrate may be used. Moreover, in order to give electronic conductivity, you may use electronic conductive materials, such as a carbon fiber, a metal fiber, or carbon fine powder. The thickness of the anode gas diffusion layer 214 is not particularly limited, but is usually 100 to 500 μm.

The cathode gas diffusion layer 215 is laminated on the main surface of the cathode catalyst layer 213 in order to play the following two roles.
The first role is to efficiently guide the oxidant flowing from the cathode channel 27 described later to the cathode catalyst layer 213.
The second role is to supply electrons supplied to the cathode current collector 23 described later to the cathode catalyst layer 213 after passing through the external load 41 from the anode current collector 22.

  Here, the specific material used for the cathode gas diffusion layer 215 is not particularly limited as long as it can play the above role, and a cathode gas diffusion layer known in the art can be used. For example, the same material as the anode gas diffusion layer 214 can be used. The thickness of the cathode gas diffusion layer 215 is not particularly limited, but is usually 100 to 500 μm.

  The electrolyte membrane 211, the anode catalyst layer 212 and the cathode catalyst layer 213 laminated on the front and back surfaces, respectively, and the anode gas diffusion layer 214 and the cathode gas diffusion layer 215 laminated on the front and back surfaces, respectively, The shape is appropriate according to the outer shape of the fuel cell 2, such as a rectangle, a circle, an ellipse, or a polygon. The outer edges of the anode catalyst layer 212 and the cathode catalyst layer 213 are not particularly limited, but generally have an outer edge smaller than the outer edge of the electrolyte membrane 211, and the outer edges of the anode gas diffusion layer 214 and the cathode gas diffusion layer 215 are The outer edge shape of each of the anode catalyst layer 212 and the cathode catalyst layer 213 is almost the same as the outer edge shape.

(Fuel cell structure)
Next, as shown in FIG. 2, as an explanation of each structure of the fuel cell 2, an anode current collector 22, a cathode current collector 23, an anode separator 24, a cathode separator 25, a gasket 28, a gasket 29, and The reinforcing layer 216A and the reinforcing layer 216B will be described.

The anode current collector 22 is provided on the outer surface of the anode separator 24 in order to supply electrons supplied from the anode catalyst layer 212 and an anode separator 24 described later to an external load 41 described later. Here, as a material used for the anode current collector 22, for example, a metal plate such as a copper plate having a thickness of 1 to 3 mm coated with a metal such as gold having a thickness of 3 to 4 μm is used. it can.
The anode current collector 22 is connected to the cathode (minus) of the external load 41 via wiring (not shown).

The cathode current collector 23 is provided on the outer surface of the cathode separator 25 in order to supply electrons supplied from the external load 41 to the cathode separator 25 and the cathode catalyst layer 213 described later. Here, as a material used for the cathode current collector 23, for example, the same material as that of the anode current collector 22 can be used.
The cathode current collector 23 is connected to the anode (plus) of the external load 41 through wiring (not shown).

The anode separator 24 is laminated on the main surface of the anode gas diffusion layer 214 in order to play the following four roles.
The first role is to mechanically fix the membrane electrode assembly 21.
The second role is to supply an aqueous methanol solution from the inlet 241 of the anode channel to the anode catalyst layer 212 via the anode channel 26 formed on the surface in contact with the anode gas diffusion layer 214.
The third role is to supply electrons generated from the anode catalyst layer 212 and supplied from the anode gas diffusion layer 214 to the anode current collector 22.
The fourth role is that anode discharge (discharged product of anode (carbon dioxide, formaldehyde, formic acid, etc.) and methanol unreacted in the anode catalyst layer 212, etc.) discharged from the anode catalyst layer 212 is transferred to the anode channel 26. To the anode channel outlet 242.
Here, as a material used for the anode separator 24, conductive members, such as carbon, the synthetic material of carbon and a synthetic resin, or a metal, are mentioned, for example.
The outer shape of the anode separator 24 is appropriately selected according to the outer shape of the membrane electrode assembly 21.

The cathode separator 25 is laminated on the main surface of the cathode gas diffusion layer 215 in order to play the following four roles.
The first role is to mechanically fix the membrane electrode assembly 21.
The second role is to supply the oxidant from the inlet 241 of the anode channel to the cathode catalyst layer 213 through the cathode channel 27 formed on the surface in contact with the cathode gas diffusion layer 215.
The third role is to supply electrons supplied from the cathode current collector 23 through the external load 41 to the cathode catalyst layer 213 from the inlet 251 of the cathode channel.
The fourth role is that the cathode exhaust (cathode product (water, water vapor, etc.) discharged from the cathode catalyst layer 213 and the anode catalyst layer 212 pass through the membrane electrode assembly 21 without causing an oxidation reaction. The product (the same product as the above anode product) produced by the oxidation reaction of the aqueous methanol solution transported to the cathode catalyst layer 213 in the cathode catalyst layer 213, the unreacted aqueous methanol solution in the cathode catalyst layer 213, etc. Then, it is carried away through the cathode channel 27 to the outlet 252 of the cathode channel.
Here, as a material used for the cathode separator 25, the same thing as the anode separator 24 is mentioned, for example.
The outer shape of the cathode separator 25 is appropriately selected according to the outer shape of the membrane electrode assembly 21.

  Here, the anode flow path 26 and the cathode flow path 27 are formed by providing grooves on the surface of the anode separator 24, although illustration in plan view is omitted. Although not particularly limited, the anode flow channel 26 and the cathode flow channel 27 are configured by, for example, a plurality of linear groove portions and a plurality of turn-shaped groove portions that connect adjacent linear groove portions from upstream to downstream. A serpentine shape or a linear shape composed of a plurality of linear grooves.

  The gasket 28 and the gasket 29 are provided around the anode gas diffusion layer 214 and the cathode gas diffusion layer 215 in order to prevent the methanol aqueous solution and the oxidant from leaking to the outside and to prevent them from mixing. Respectively. Moreover, as a material used for the gasket 28 and the gasket 29, a well-known thing in the said field | areas, such as rubber | gum, is mentioned. Further, the outer shape of the gasket 28 and the gasket 29 is a shape corresponding to the outer shape of the anode separator 24 and the cathode separator 25, and may be a frame shape (frame shape) or an annular shape.

  The reinforcing layer 216 </ b> A and the reinforcing layer 216 </ b> B are disposed so as to sandwich the outer edge portions of the upper surface and the lower surface of the electrolyte membrane 211 in order to increase the mechanical strength of the electrolyte membrane 211 and suppress expansion / contraction. The The material used for the reinforcing layer 216A and the reinforcing layer 216B is not particularly limited as long as the material has a desired rigidity. For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetrafluoroethylene ( And a film made of PTFE). The outer shape of the reinforcing layer 216A and the reinforcing layer 216B includes a frame shape and the like.

  Although the fuel cell 2 in FIG. 1 shows a configuration of a single cell, a multilayer fuel cell 2 in which a plurality of the single cells are stacked in the upward direction with respect to FIG. 1 may be configured according to the required electromotive force. . In that case, the multilayer type fuel cell 2 is formed by stacking the single unit fuel cells 2 and then pressing each of the uppermost and lowermost fuel cells 2 with two resin plates from above and below with respect to FIG. Thereafter, the fuel cell 2 and the resin plate can be mechanically fixed with bolts.

(Structure of fuel cell system)
Next, as shown in FIG. 1, as an explanation of each structure of the fuel cell system 1, a fuel tank 31, a filter 32, an oxidant supply unit 33, an oxidant supply amount adjustment unit 34, and a flow path opening degree. The adjusting unit 35, the condensing unit 36, the circulation tank 37, the control unit 38, the pipes F1 to F8, and the pumps G1 to G3 will be described.
Here, as shown in FIG. 1, the fuel cell 2, the fuel tank 31, the filter 32, the oxidant supply unit 33, the oxidant supply amount adjustment unit 34, the flow path opening degree adjustment unit 35, and the condensation The part 36, the circulation tank 37, the control part 38, the pipes F1 to F8, and the pumps G1 to G3 are accommodated in one housing.

The fuel tank 31 serves to store a methanol aqueous solution supplied to the inlet 241 of the anode flow path.
Here, the aqueous methanol solution stored in the fuel tank 31 is about 2% of about 59% high-concentration methanol aqueous solution supplied from an external fuel tank 40 described later by water supplied from a circulation tank 37 described later. Diluted to ˜3% is stored.
The anode discharge discharged from the outlet 242 of the anode flow path is separated into a gas phase and a liquid phase in the fuel tank 31. Specifically, gas phase components such as carbon dioxide, methanol vapor, formaldehyde, and formic acid transported from the fuel cell 2 are transferred into the fuel tank 31 and then float on the liquid surface of the aqueous methanol solution to form water or methanol. It is separated from a liquid phase component such as a solution and exists in the fuel tank 31.
Although not shown in FIG. 1, the fuel tank 31 may be configured as follows as a mechanism for measuring the fuel concentration in order to keep the fuel concentration constant.
That is, a pipe having one end and the other end connected in a loop to the fuel tank 31, and a methanol concentration meter and a liquid pump installed in the pipe may be provided.
As shown in FIG. 1, the fuel tank 31 is connected to pipes F1, F3, and F5 to F7 described later.

The filter 32 serves to remove dust and the like contained in the air taken from the outside of the fuel cell system 1.
Moreover, as shown in FIG. 1, the filter 32 is provided in the piping F2 mentioned later.

The oxidant supply unit 33 is, for example, an air pump such as an air blower or an air compressor, and supplies the oxidant taken from the outside of the fuel cell system 1 to the inlet 251 of the cathode flow path of the fuel cell 2. The amount is increased, and the oxidant is supplied to the inlet 251 of the cathode channel.
As shown in FIG. 1, the oxidant supply unit 33 is connected to the filter 32 and the inlet 251 of the cathode flow path of the fuel cell 2 via a pipe F <b> 2 described later.

The oxidant supply amount adjusting unit 34 is an operation panel of an air pump, for example, and plays a role of adjusting the supply amount of the oxidant supplied from the oxidant supply unit 33.
Here, as a means for adjusting the supply amount of the oxidant, for example, increasing or decreasing the output of the oxidant supply unit 33 may be mentioned.
Further, as shown in FIG. 1, the oxidant supply amount adjusting unit 34 is provided in the oxidant supply unit 33.

The channel opening degree adjustment unit 35 is, for example, an electric valve or the like, and has a channel opening degree in the pipe F4 described later, that is, the size of the cross-sectional area shown along the direction perpendicular to the extending direction of the pipe F4. It plays a role to coordinate.
Hereinafter, increasing the channel opening degree is defined as increasing the size of the cross-sectional area, and decreasing the channel opening degree is defined as decreasing the size of the cross-sectional area.
Moreover, as shown in FIG. 1, the flow path opening degree adjustment part 35 is provided in the piping F4 mentioned later.

The condensing part 36 plays the role which condenses the water vapor | steam which arises in the cathode pole and was sent to the piping F4 mentioned later, and liquefies as water. Thereby, it becomes possible to add water in the circulation tank 37 by transporting the water liquefied by the pipe F4 to the circulation tank 37 described later. That is, water vapor generated at the cathode electrode can be reused as water in the circulation tank 37.
Although not shown in FIG. 1, in order to cool the water vapor in order to further condense the water vapor in the condensing unit 36, the pipe F4 includes a condensing unit 36 and a cathode channel. A radiator may be provided between the first and second inlets 251.
Moreover, as shown in FIG. 1, the condensing part 36 is provided in the piping F4 mentioned later.

The circulation tank 37 plays a role of storing water supplied to the fuel tank 31. This makes it possible to dilute about 59% of a highly concentrated aqueous methanol solution supplied from an external fuel tank 40, which will be described later, to about 2-3%. For this reason, since it becomes possible to supply the methanol aqueous solution of low concentration to the inlet 241 of an anode flow path, since the quantity of unreacted methanol aqueous solution decreases, it becomes possible to suppress generation | occurrence | production of methanol crossover. Become.
Further, the anode discharge discharged from the anode flow path outlet 242 and the cathode discharge discharged from the cathode flow path outlet 252 are separated into a gas phase and a liquid phase in the circulation tank 37. Specifically, gas phase components such as carbon dioxide, methanol vapor, formaldehyde, formic acid, and water vapor transported from the fuel cell 2 are transferred into the circulation tank 37 and then floated on the surface of the water. It is separated from a liquid phase component such as a methanol solution and is present in the circulation tank 37.
Moreover, as shown in FIG. 1, the circulation tank 37 is connected to piping F4 and F6 to F8 described later.

The control unit 38 is a microcomputer including, for example, a signal processing IC, a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like, and plays the following five roles.
First, it plays a role of determining whether or not the flooding phenomenon has occurred in the cathode electrode during the operation of the fuel cell system 1 before the flooding phenomenon occurs (hereinafter referred to as normal operation). .
Secondly, it is determined whether or not the flooding phenomenon has been eliminated at the cathode electrode during operation of the fuel cell system 1 when the flooding phenomenon is being reduced (hereinafter referred to as “flooding phenomenon reduction operation”). Playing a role.
Third, it plays a role of controlling the oxidant supply amount adjusting unit 34 based on the above determination result.
Fourth, it plays a role of controlling the flow path opening degree adjustment unit 35 based on the above determination result.
Fifth, it plays the role of controlling the supply amount of aqueous methanol solution in pump G1, which will be described later, the supply amount of high-concentration methanol aqueous solution in pump G2, and the supply amount of water in pump G3.
Further, the control unit 38 can increase the pressure in the pipe F4 at the same time without changing the supply amount of the oxidant during the normal operation according to the following principle. That is, in general, when the supply amount of the oxidant is increased while the degree of openness of the flow path of the pipe F4 is kept constant, the pressure in the pipe F4 increases, but at the same time, the supply amount of the oxidant increases. However, when the degree of opening of the flow path of the pipe F4 is decreased, the supply amount of the oxidant is reduced at the same time while increasing the pressure in the pipe F4. For this reason, when the flow rate of the pipe F4 is decreased at the same time when the supply amount of the oxidant is increased, the pressure in the pipe F4 is maintained while maintaining the same amount as the supply amount of the oxidant during the normal operation. Can be raised.
Moreover, as shown in FIG. 1, the control part 38 is electrically connected with the fuel cell 2, the oxidizing agent supply amount adjustment part 34, the flow-path openness adjustment part 35, and the pumps G1-G3 mentioned later.
The fuel cell system 1 includes a voltage sensor (not shown) for detecting the output voltage value of the fuel cell 2 between the fuel cell 2 and the control unit 38, and an output current value of the fuel cell 2. A current sensor (not shown) for detection is attached. The current sensor and the voltage sensor serve to transmit a power value calculated from each output value of the sensor to the control unit 38.
Further, the control unit 38 determines whether or not a flooding phenomenon has occurred at the cathode electrode, or has reached the value of the oxidant supply amount and the degree of openness of the pipe F4 as the optimum conditions in the flooding phenomenon reducing operation. No, a power value information storage unit (not shown) is provided as a storage device for storing various parameter information necessary for determining whether the flooding phenomenon has been resolved. As a result, the control unit 38 can determine whether a flooding phenomenon has occurred in the cathode electrode.
In addition, when the control unit 38 shifts from the normal operation to the flooding reduction operation, the control unit 38 can supply the oxidant supply as a control data value so that it can maintain the same amount as the supply amount of the oxidant during the normal operation. A table (hereinafter referred to as the value of the oxidant supply amount in the oxidant supply unit 33 adjusted by the amount adjustment unit 34 and the value of the channel opening degree of the pipe F4 adjusted by the channel opening degree adjustment unit 35). A control information storage unit (not shown) in which the control information table is recorded in advance. Here, the control data value is set in advance to an optimum value for eliminating the flooding phenomenon. Further, the control information table is changed in accordance with the operating conditions of the fuel cell 2 necessary for obtaining the optimum power value of the fuel cell 2 such as the temperature of the fuel cell 2 and the concentration of the aqueous methanol solution. A plurality of each is provided for each operating condition. Therefore, after determining that the flooding phenomenon has occurred in the cathode electrode, the control unit 38 confirms the operating condition of the fuel cell 2 and controls the optimum control condition for the operating condition of the fuel cell 2 among the plurality of control information tables. An information table is selected from the control information storage unit. Then, the control unit 38 refers to the oxidant supply amount U1 and the flow path opening degree V1 of the pipe F4 as the control data values described in the selected control information table, and oxidizes until reaching these values. It is possible to control the agent supply amount adjusting unit 34 and the flow path opening degree adjusting unit 35, respectively.

The pipes F <b> 1 to F <b> 8 play the role of transporting the liquid and gas described above as flow paths for various liquids and gases in the fuel cell system 1, and are provided as follows.
The pipe F1 plays a role of supplying the methanol aqueous solution in the fuel tank 31 to the inlet 241 of the anode flow path, and is connected to the fuel tank 31 and the inlet 241 of the anode flow path.
The pipe F2 serves to supply the oxidant taken from the outside of the fuel cell system 1 to the oxidant supply unit 33 via the filter 32, and the oxidant discharged from the oxidant supply unit 33 to the cathode flow path of the fuel cell 2. And is connected to the filter 32 and the inlet 251 of the cathode flow channel.
The pipe F3 serves to supply the anode discharge discharged from the outlet 242 of the anode flow path to the fuel tank 31, and is connected to the outlet 242 of the anode flow path and the fuel tank 31.
The pipe F4 supplies the cathode discharge discharged from the outlet 252 of the cathode flow path to the condensing unit 36, and then, in the condensing unit 36, water generated from water vapor other than the above-described cathode products and water other than water It plays the role of supplying the cathode discharge to the circulation tank 37, and is connected to the outlet 252 of the cathode flow path and the circulation tank 37.
The pipe F5 plays a role of supplying a high-concentration methanol aqueous solution in the external fuel tank 40 described later to the fuel tank 31, and is connected to the external fuel tank 40 and the fuel tank 31.
The pipe F6 plays the role of supplying the anode discharge to the circulation tank 37 for the purpose of discharging the anode discharge existing in the fuel tank 31 to the outside of the fuel cell system 1. 31 and the circulation tank 37.
The pipe F <b> 7 plays a role of supplying the water in the circulation tank 37 to the fuel tank 31, and is connected to the circulation tank 37 and the fuel tank 31.
The pipe F8 plays a role of discharging the anode discharge supplied from the pipe F6 and the cathode discharge supplied from the pipe F4 existing in the circulation tank 37 to the outside of the fuel cell system 1. One end is connected to the circulation tank 37 and the other end is opened to the outside of the fuel cell system 1.

The pumps G1 to G3 are liquid pumps such as a diaphragm pump and a plunger pump, for example, and play a role of adjusting the supply amounts of various liquids in the fuel cell system 1, and are provided as follows. Yes.
The pump G1 plays a role of adjusting the supply amount of the methanol aqueous solution supplied from the fuel tank 31 toward the inlet 241 of the anode flow path, and is provided in the pipe F1.
The pump G2 plays a role of adjusting the amount of methanol aqueous solution supplied from the external fuel tank 40 toward the fuel tank 31, and is provided in the pipe F5.
The pump G3 plays the role of adjusting the amount of water supplied from the circulation tank 37 toward the fuel tank 31, and is provided in the pipe F7.

  The fuel cell system 1 is configured by the above structures. Next, the external fuel tank 40 and the external load 41 will be described as the description of each structure outside the fuel cell system 1.

The external fuel tank 40 plays a role of storing high concentration methanol supplied to the fuel tank 31.
Moreover, as shown in FIG. 1, the external fuel tank 40 is connected to the pipe F5.

The external load 41 is a power device that uses the power supplied from the fuel cell 2.
The external load 41 is connected to the anode current collector 22 above the anode separator 24 and the cathode current collector 23 above the cathode separator 25 via wiring.

(Operating principle of fuel cell system)
With the above configuration, the fuel cell system 1 can supply the electric power generated from the fuel cell 2 to the external load 41 according to the following principle.
First, the methanol aqueous solution supplied from the fuel tank 31 is supplied to the inlet 241 of the anode flow path, then passes through the anode flow path 26 of the anode separator 24 and permeates the anode gas diffusion layer 214, and then the anode catalyst layer. 212 is reached.
Next, only after the aqueous methanol solution reaches the anode catalyst layer 212, as shown in the following formula (1), an oxidation reaction occurs between methanol and water contained in the aqueous methanol solution, and protons and electrons are generated from the aqueous methanol solution. And carbon dioxide is produced.
CH3OH + H2O → CO2 + 6H ++ 6e− (1)
Next, the generated protons move from the anode catalyst layer 212 to the surface of the electrolyte membrane 211, pass through the inside of the electrolyte membrane 211, and are supplied to the cathode catalyst layer 213 before long.
Further, the generated electrons are supplied to the cathode catalyst layer 213 in the order of “1” to “9” below.
“1” anode catalyst layer 212, “2” anode gas diffusion layer 214, “3” anode separator 24, “4” anode current collector 22, “5” external load 41, “6” cathode current collector 23, “ 7 ”cathode separator 25,“ 8 ”cathode gas diffusion layer 215, and“ 9 ”cathode catalyst layer 213.
Next, after the oxidant supplied from the oxidant supply unit 33 is supplied to the inlet 251 of the cathode flow path, it passes through the cathode flow path 27 of the cathode separator 25 and permeates the cathode gas diffusion layer 215. The cathode catalyst layer 213 is reached.
In addition, protons and electrons supplied to the cathode catalyst layer 213 cause a reduction reaction with the oxidant described above to generate water.
3 / 2O2 + 6H ++ 6e− → 3H2O (2)
Through the above oxidation reaction and reduction reaction, a current flows through the fuel cell 2, and power can be supplied from the fuel cell 2 to the external load 41.

  Next, the operation of the control unit 38 in the present embodiment when shifting from the normal operation to the flooding phenomenon reducing operation will be described in detail with reference to FIG. 4 based on the following steps S101 to S110.

  FIG. 4 is a flowchart showing a control procedure of normal operation and flooding phenomenon reduction operation in the control unit according to the first embodiment of the present invention.

First, the fuel cell system 1 is activated and current is supplied to the fuel cell 2 (step S101).
Then it starts monitoring the power value in the fuel cell 2 at the same time energizing start and to the fuel cell 2, after setting the time interval Δt1 from the monitoring start time t _a until a predetermined time t _b, in the time interval Δt1 After the voltage sensor detects the average output voltage of the fuel cell 2 and the current sensor detects the average output current of the fuel cell 2, the average power value W1 (hereinafter referred to as power) of the fuel cell 2 is calculated from the output values of both sensors. The power value W1 is stored in a power value information storage unit (not shown) included in the control unit 38 and set (step S102).
Then, by monitoring the power value of the fuel cell 2 at all times, after setting the time interval .DELTA.t2 to monitor end time t _c from the predetermined time t _b, the average power value of the fuel cell 2 in the time interval .DELTA.t2 W2 (W1> W2, hereinafter defined as power value W2) is acquired at an arbitrary time (step S103).
Next, a difference ΔW between the power value W1 and the power value W2 is calculated (step S104).
Next, it is determined whether or not the difference ΔW between the power value W1 and the power value W2 is equal to or greater than a predetermined value S1 (step S105).
Here, when the control unit 38 determines in step S105 that the difference ΔW between the power value W1 and the power value W2 is not equal to or greater than the predetermined value S1 (in the case of NO), the power value of the fuel cell 2 is It is determined that there is no relatively large drop and no flooding phenomenon has occurred, and the process returns to step S103 and is repeated until step S104. On the other hand, when the control unit 38 determines that the difference ΔW between the power value W1 and the power value W2 is a value equal to or greater than the predetermined value S1 (in the case of YES), the power value of the fuel cell 2 decreases relatively large. Therefore, it is determined that the flooding phenomenon has occurred. In this case, the control unit 38 confirms the operating conditions of the fuel cell 2 such as the temperature of the fuel cell 2 and the concentration of the aqueous methanol solution, and among the plurality of control information tables, the control information optimal for the operating condition of the fuel cell 2 is obtained. A table is selected from the control information storage unit (step S106).
Next, the control unit 38 controls each control data value of the oxidant supply amount and the degree of openness of the pipe F4 described in the selected control information table (hereinafter, this value is referred to as the oxidant supply amount U1, Reference is made to the opening degree V1 of the pipe F4 (step S107).
Next, the control unit 38 outputs an oxidant supply amount increase control signal for controlling the oxidant supply amount adjustment unit 34 so that the oxidant supply amount increases until the oxidant supply amount U1 referred to above is reached. Further, a flow path opening degree reduction control signal for controlling the flow path opening degree adjusting unit 35 is generated so that the flow degree of opening of the pipe F4 decreases until the flow path opening degree V1 referred to above is reached. Thereafter, the control unit 38 transmits the oxidant supply amount increase control signal generated as described above to the oxidant supply amount adjustment unit 34, and at the same time transmits a flow path opening degree decrease control signal to the flow path opening degree adjustment unit 35. (Step S108).
Next, based on the oxidant supply amount increase control signal transmitted from the control unit 38 in step S108, the oxidant supply amount adjustment unit 34 refers to the oxidant supply amount U0 already set during normal operation. The adjustment (oxidant supply amount increase control) for increasing the oxidant supply amount in the oxidant supply unit 33 is executed until the oxidant supply amount U1 is reached. Furthermore, the flow path opening degree adjustment unit 35 is based on the flow path opening degree reduction control signal transmitted from the control unit 38 in step S108 while maintaining the same amount as the supply amount of the oxidant during normal operation. Adjustment to reduce the degree of openness of the pipe F4 until the degree of openness V1 of the pipe F4 referred to above is reached from the degree of openness V0 of the pipe F4 already set during normal operation (decrease in degree of openness of the path) Control) is executed simultaneously with the above-described oxidant supply amount increase control (step S109).
Finally, after executing the oxidant supply amount increase control and the flow path opening degree decrease control in step S109, a predetermined time T1 set in advance that can be determined from an empirical rule when the power value of the fuel cell 2 reaches a stable state is obtained. After elapses, the control unit 38 determines that the power value of the fuel cell 2 has reached a stable state (step S110).
By shifting from the normal operation to the flooding phenomenon reducing operation by the above procedure, the control unit 38 can reduce the flooding phenomenon while suppressing a decrease in the stable power supply in the fuel cell 2.
Further, in the above, the supply amount of the oxidant during the flooding phenomenon reducing operation is maintained at the same level as the supply amount of the oxidant during the normal operation. Here, the amount equivalent to the amount of oxidant supplied during normal operation means that the relationship between the value of oxidizer supplied during operation with reduced flooding phenomenon and the value of oxidant supplied during normal operation is as follows: It means that it may be street. That is, the value of the oxidant supply amount during the flooding reduction operation is not limited to the same value as the oxidant supply amount during the normal operation. For example, the value of the oxidant supply amount during the flooding reduction operation is It may be a value including an error of up to ± 3.0% with respect to the value of the supply amount of the oxidant during normal operation.
As for the time interval Δt1, the time interval Δt2, the predetermined time T1, and the predetermined value S1, it is possible to use values desired by the user. For the predetermined value S1, the energization start of the fuel cell system is started. It is preferable to set a value that represents the rate of decrease in the power value of the fuel cell 2 that has decreased from the time until the occurrence of the flooding phenomenon, and as this specific value, for example, among the values calculated from the following equation (3) , 3 to 6 (%) is preferably set and used in advance. However, in the following formula (3), a is the power value (mW / cm ² ) of the fuel cell immediately after the start of energization of the fuel cell system, and b is the fuel measured after 1 hour from the start of energization of the fuel cell system. It is the electric power value (mW / cm ² ) of the battery.

Further, when the supply amount of the oxidant and the degree of openness of the pipe F4 are set as the optimum condition values for obtaining the fuel cell 2 having a high power value during the normal operation, the above-described operation is performed when the flooding phenomenon is reduced. In order to change the supply amount of the oxidant and the degree of opening of the pipe F4 from the optimum condition value, the power value of the fuel cell 2 is lower than that during normal operation. Therefore, in this case, in order to obtain as high a power value as possible for the fuel cell 2, the operation state of the fuel cell system 1 is changed from the flooding phenomenon reduction operation after a predetermined time has elapsed since the start of the flooding phenomenon reduction operation. It is necessary to return to normal operation.
Therefore, the operation of the control unit 38 in the present embodiment when returning from the flooding phenomenon reducing operation to the normal operation will be described in detail with reference to FIG. 5A based on the following steps S111 to S113.

  FIG. 5 is a flowchart showing a control procedure of flooding phenomenon reduction operation and normal operation in the control unit according to the first embodiment of the present invention.

First, through the step S110, the control unit 38, until the supply amount of the oxidant after the transition to the normal operation becomes the same amount as the supply amount of the oxidant in the normal operation before the flooding phenomenon reduction operation, An oxidant supply amount decrease control signal for controlling the oxidant supply amount adjustment unit 34 is generated so that the oxidant supply amount is decreased. Further, the degree of openness of the pipe F4 increases until the degree of openness of the pipe F4 after the transition to the normal operation becomes approximately the same as the degree of openness of the pipe F4 during the normal operation before the flooding reduction operation. In this manner, a flow path opening degree increase control signal for controlling the flow path opening degree adjusting unit 35 is generated. Thereafter, the control unit 38 transmits the oxidant supply amount decrease control signal generated as described above to the oxidant supply amount adjustment unit 34, and at the same time, transmits the flow channel opening degree increase control signal to the flow channel opening degree adjustment unit 35. (Step S111).
Finally, based on the oxidant supply amount decrease control signal transmitted from the control unit 38 in step S111, the oxidant supply amount adjustment unit 34 determines that the supply amount of oxidant after the shift to the normal operation is a flooding phenomenon. Adjustment (oxidant supply amount decrease control) is performed to reduce the oxidant supply amount in the oxidant supply unit 33 until the oxidant supply amount U0 in the normal operation before the reduction operation is reached. Further, the flow rate opening degree adjusting unit 35 is maintained based on the flow rate opening degree increase control signal transmitted from the control unit 38 in step S111 while maintaining the same amount as the supply amount of the oxidant during the flooding phenomenon reducing operation. Shows the degree of opening of the pipe F4 until the degree of opening of the pipe F4 after the transition to the normal operation becomes approximately the same as the degree of opening V0 of the pipe F4 during the normal operation before the flooding phenomenon reducing operation. Adjustment (increase control of opening degree of flow path) for increasing is executed (step S112). As a result, the supply amount of the oxidant and the degree of opening of the pipe F4 are approximately the same as those in the normal operation before the flooding phenomenon reducing operation.
Finally, after executing the oxidant supply amount decrease control and the flow path opening degree increase control in step S112, a preset predetermined time T2 that can be determined from an empirical rule when the power value of the fuel cell 2 reaches a stable state is set. After elapses, the control unit 38 determines that the power value of the fuel cell 2 has reached a stable state (step S113).
With the above procedure, the operation state of the fuel cell system 1 returns from the flooding phenomenon reduction operation to the normal operation.
In the above description, the supply amount of the oxidant after the shift to the normal operation is maintained at the same level as the supply amount of the oxidant during the flooding phenomenon reduction operation. Here, the amount of oxidant supplied at the time of the flooding reduction operation means the value of the oxidant supply after the shift to the normal operation and the value of the oxidant supply during the flooding reduction operation. This means that the relationship may be as follows. That is, the value of the oxidant supply amount after the shift to the normal operation is not limited to the same value as the value of the oxidant supply amount at the time of the flooding reduction operation, for example, the supply of the oxidant after the shift to the normal operation. The value of the amount may be a value including an error of up to ± 3.0% with respect to the value of the supply amount of the oxidant during the flooding phenomenon reduction operation.
Further, the oxidant supply amount decrease control in step S112 may be performed simultaneously with the flow channel opening degree increase control while maintaining the same amount as the oxidant supply amount during the flooding phenomenon reduction operation. Although it may be performed separately regardless of the order of opening degree increase control, it is possible to return to the normal operation from the flooding phenomenon reduction operation while maintaining the stability of the pressure in the pipe F4. It is preferable to carry out at the same time as the flow path opening degree increase control while maintaining the same amount as the supply amount of the oxidant.
Further, after the step S113, a series of steps from the step S103 to the step S113 may be performed once or a plurality of times. Here, the number of times of performing the series of steps S103 to S113 performed after step S113 is not particularly limited, and may be one or more times, but is preferably performed every time a flooding phenomenon occurs.
Further, in the present embodiment, when there is a situation that the fuel cell system 1 may be operated with the power value of the fuel cell 2 obtained during the flooding phenomenon reduction operation, such as when the operation time of the fuel cell system 1 is short, Steps S111 to S113 are not necessarily performed. During the operation period of the fuel cell system 1, the fuel cell system 1 may be operated in an operation state in which the flooding phenomenon is reduced.

In addition, when the flooding phenomenon reducing operation is performed for a long time, the oxidant is supplied to the cathode catalyst layer 213 for a long time, so that the cathode catalyst layer 213 is gradually dried. As a result, the potential of the cathode electrode increases, and the catalyst in the cathode catalyst layer 213 gradually oxidizes, so that the catalyst deteriorates and the power value of the fuel cell 2 may be reduced.
Therefore, in order to reduce the oxidized catalyst in the cathode catalyst layer 213 for the purpose of recovering the reduced power value in the fuel cell 2, the following steps S114 to S119 may be performed instead of the above steps S111 to S113. Good.
As a result, before returning from the flooding phenomenon reducing operation to the normal operation, it is possible to perform an operation for stopping the supply of the oxidant in the oxidant supply unit 33 (hereinafter, referred to as an oxidant supply stop operation). The active material supplied to the battery 2 can be limited to only an aqueous methanol solution. For this reason, the potential of the cathode electrode can be lowered by sufficiently penetrating the aqueous methanol solution supplied from the anode electrode side into the cathode electrode. As a result, since the oxidized catalyst is reduced, the reduced power value in the fuel cell 2 can be recovered.
Next, using FIG. 5B, based on the following steps S114 to S119, the operation of the control unit 38 in the present embodiment when returning from the flooding phenomenon reduction operation to the normal operation using the oxidant supply stop operation. Will be described in detail.

First, after step S110, the control unit 38 generates an oxidant supply stop control signal for controlling the oxidant supply amount adjusting unit 34 so that the supply of the oxidant in the oxidant supply unit 33 is stopped. Then, a flow path opening degree increase control signal for controlling the flow path opening degree adjusting unit 35 is generated so that the flow degree of the pipe F4 is increased. Thereafter, the control unit 38 transmits the oxidant supply stop control signal generated as described above to the oxidant supply amount adjustment unit 34, and at the same time, transmits the flow path opening degree increase control signal to the flow path opening degree adjustment unit 35. (Step S114).
Next, based on the oxidant supply stop control signal transmitted from the control unit 38 in step S <b> 114, the oxidant supply amount adjusting unit 34 adjusts to stop the oxidant supply amount in the oxidant supply unit 33 (oxidant). Supply stop control), and further, based on the flow rate opening degree increase control signal transmitted from the control unit 38 in step S114, the flow rate opening degree adjustment unit until the flow rate degree of the pipe F4 becomes maximum. 35 performs adjustment (flow path opening degree increase control) for increasing the flow path opening degree of the pipe F4 (step S115).
Next, after executing the oxidant supply stop control and the flow path opening degree increase control in step S115, a predetermined time T3 that can be determined from an empirical rule when the oxidized catalyst reaches a sufficiently reduced state has elapsed. After that, the control unit 38 determines that the oxidized catalyst has been sufficiently reduced (step S116).
Next, the controller 38 supplies the oxidant until the supply amount of the oxidant after the shift to the normal operation becomes the same amount as the supply amount of the oxidant during the normal operation before the flooding phenomenon reducing operation. An oxidant supply amount increase control signal for controlling the oxidant supply amount adjustment unit 34 so as to increase is generated. Further, the degree of openness of the pipe F4 decreases until the degree of openness of the pipe F4 after the transition to the normal operation becomes approximately the same as the degree of openness of the pipe F4 during the normal operation before the flooding phenomenon reducing operation. In this manner, a flow path opening degree reduction control signal for controlling the flow path opening degree adjusting unit 35 is generated. Thereafter, the generated oxidant supply amount increase control signal is transmitted to the oxidant supply amount adjustment unit 34, and at the same time, the flow path opening degree decrease control signal is transmitted to the flow path opening degree adjustment unit 35 (step S117).
Next, based on the oxidant supply amount increase control signal transmitted from the control unit 38 in step S117, the oxidant supply amount adjustment unit 34 operates to reduce the flooding phenomenon after the shift to the normal operation. Perform adjustment (oxidant supply amount increase control) to increase the supply amount of the oxidant in the oxidant supply unit 33 until the amount is approximately the same as the supply amount U0 of the oxidant in the previous normal operation. Based on the flow path opening degree decrease control signal transmitted from the control unit 38 in step S117, the flow path opening degree adjustment unit 35 determines that the flow degree of the pipe F4 after the shift to the normal operation is before the flooding phenomenon reducing operation. Adjustment (flow path opening degree reduction control) is executed to reduce the flow path opening degree of the pipe F4 until the flow opening degree V0 of the pipe F4 during the normal operation is approximately the same (step S1). 8). As a result, the supply amount of the oxidant and the degree of opening of the pipe F4 are approximately the same as those in the normal operation before the flooding phenomenon reducing operation.
Finally, after executing the oxidant supply amount increase control and the flow path opening degree decrease control in step S118, a predetermined time T4 that can be determined from an empirical rule when the power value of the fuel cell 2 reaches a stable state is determined. After elapses, the control unit 38 determines that the power value of the fuel cell 2 has reached a stable state (step S119).
With the above procedure, the operation state of the fuel cell system 1 returns from the flooding phenomenon reduction operation to the normal operation.
The oxidant supply stop control in step S115 may be performed simultaneously with the flow path opening degree increase control, or may be performed separately from the flow path opening degree increase control regardless of the order, but the flow path opening degree increase. It is preferable to perform the control simultaneously with the control or after the flow path opening degree increase control. This is because if the oxidant supply stop control is performed with the opening degree of the pipe F4 being small, air or water tends to remain in the cathode electrode, and the back pressure on the cathode electrode side becomes high. There may be a problem that the amount of the methanol aqueous solution penetrating the cathode electrode side is suppressed, and the oxidized cathode catalyst layer 213 cannot be sufficiently reduced. Therefore, the oxidant supply stop control in step S115 is performed at the same time as the flow path opening degree increase control or after the flow path opening degree increase control, thereby maintaining a relatively high flow degree opening degree state. Since the oxidant supply stop control can be performed as it is, air and water can be suppressed from remaining on the cathode electrode, and the back pressure on the cathode electrode side can be suppressed from increasing. The methanol aqueous solution can be sufficiently permeated into the cathode electrode side, and the oxidized cathode catalyst layer 213 can be sufficiently reduced.
Further, in the flow path opening degree increase control in step S115, the magnitude of the flow path opening degree of the pipe F4 after the control is not particularly limited, but the oxidant supply stop control while maintaining a higher flow path opening degree state. Since the oxidized cathode catalyst layer 213 can be more sufficiently reduced, the flow rate opening degree adjustment unit 35 is controlled until the flow rate of the pipe F4 is maximized. It is preferable.
Further, the oxidant supply amount increase control in step S118 may be performed simultaneously with the flow path opening degree decrease control, or may be performed separately from the flow path opening degree decrease control regardless of the order, but in the pipe F4. Since it is possible to return to the normal operation from the flooding phenomenon reduction operation while maintaining the stability of the pressure, it is preferable to perform the flow rate opening degree reduction control at the same time.
In the above description, the supply amount of the oxidant after the shift to the normal operation is maintained at the same level as the supply amount of the oxidant during the flooding phenomenon reduction operation. Here, the amount of oxidant supplied at the time of the flooding reduction operation means the value of the oxidant supply after the shift to the normal operation and the value of the oxidant supply during the flooding reduction operation. This means that the relationship may be as follows. That is, the value of the oxidant supply amount after the shift to the normal operation is not limited to the same value as the value of the oxidant supply amount at the time of the flooding reduction operation, for example, the supply of the oxidant after the shift to the normal operation. The value of the amount may be a value including an error of up to ± 3.0% with respect to the value of the supply amount of the oxidant during the flooding phenomenon reduction operation.
In addition, after step S119, the steps from step S103 to step S110 may be performed again, and then a series of steps from step S114 to step S119 may be performed once or a plurality of times. Here, the number of times the series of steps performed after step S119 is performed is not particularly limited and may be one or more times, but is preferably performed every time a flooding phenomenon occurs.
In the present embodiment, if there is a circumstance that the fuel cell 2B may be operated with the power value of the fuel cell 2B obtained during the flooding phenomenon reduction operation, such as when the operation time of the fuel cell system 1B is short, S114. -S119 are not necessarily implemented, and the fuel cell system 1 may be operated in the flooding phenomenon reducing operation state throughout the operation period of the fuel cell system 1.

  In addition, the parameter used for the above determination in the control unit 38 is not limited to the power values W1, W2, and W3 of the fuel cell 2, and other parameters may be used. For example, the power value of the fuel cell 2 Instead of this, the amount of drainage at the outlet 252 of the cathode channel may be used. Here, when the amount of drainage is used as a parameter used for the above determination, the amount of drainage is measured after measuring the amount of drainage using a flow sensor for water instead of the current sensor and the voltage sensor used outside the control unit 38. Can be used as a parameter by transmitting to the control unit 38.

(Operational effect of the fuel cell system 1 in the first embodiment)
Next, the effect of the fuel cell system 1 in the present embodiment will be described in comparison with a conventional fuel cell system.

In the conventional fuel cell system, as a means of reducing the flooding phenomenon, when the occurrence of the flooding phenomenon is detected, the flow rate of the oxidant gas supplied to the cathode electrode of the fuel cell is increased, so that excessive moisture is removed from the fuel cell. Was discharged.
However, in the conventional fuel cell system, when the flow rate of the oxidant gas is increased in order to reduce the flooding phenomenon, the reduction reaction in the cathode catalyst layer is further promoted. Since the amount further increases, the amount of excess water produced tends to increase.
For this reason, since the flow path of the oxidant gas is likely to be blocked by the excessively generated water, the excessively generated water and the oxidant gas are liable to stay in the flow path, so that the discharge amount of the excessively generated water and the oxidant gas is reduced. Changes over time.
As a result, the pressure in the flow path of the oxidant gas becomes gradually less stable, and the fluctuation of the power value in the fuel cell increases, so that there is a problem that the stable power supply in the fuel cell decreases.

On the other hand, according to the fuel cell system 1 in the present embodiment, the flow rate of the oxidant gas supplied to the cathode electrode of the fuel cell 2 when the occurrence of the flooding phenomenon is detected at the cathode electrode as in the prior art. When it is determined that a flooding phenomenon has occurred, unlike the means simply increased, an oxidant supply amount increase control is performed to control the oxidant supply amount adjustment unit 34 so that the oxidant supply amount increases. Furthermore, the flow rate opening degree reduction control for controlling the flow rate opening degree adjustment unit 35 to oxidize the flow rate of the pipe F4 is reduced while maintaining the same amount as the supply amount of the oxidant during normal operation. A control unit 38 is provided to perform the operation of the fuel cell system 1 from the normal operation to the flooding reduction operation simultaneously with the agent supply amount increase control.
As a result, when the flooding phenomenon occurs, the control unit 38 performs the above-described increase control of the oxidant supply amount, and further maintains the same amount as the supply amount of the oxidant during normal operation while maintaining the above flow rate. Since the road openness reduction control is performed simultaneously with the oxidant supply increase control, the operation state of the fuel cell system is shifted from the normal operation to the flooding reduction operation that reduces the flooding phenomenon. However, the supply amount of the oxidizing agent does not decrease from that during the normal operation, and can be kept at the same level as the supply amount of the oxidizing agent during the normal operation. Therefore, in the present invention, since the supply amount of the oxidizing agent is not increased for the purpose of reducing the flooding phenomenon as in the prior art, the reduction reaction in the cathode catalyst layer 213 accompanying the increase in the supply amount of the oxidizing agent is suppressed. Is done.
For this reason, since the amount of water generated from the cathode catalyst layer 213 during the flooding phenomenon reducing operation can be maintained at the same level as during normal operation, the amount of excessively generated water generated can be suppressed. Is possible.
As a result, the pipe F4 is less likely to be blocked by the excessively generated water, so that the excessively generated water and the oxidant are less likely to stay in the pipe F4. It becomes possible to do.
Therefore, when reducing the flooding phenomenon, it is possible to maintain the stability of the pressure in the pipe F4, so that the power value in the fuel cell 2 is less likely to fluctuate. It is possible to suppress the deterioration of property.
Further, according to the present invention, since the control unit 38 performs the above-described oxidant supply amount increase control, the pressure in the pipe F4 increases, and as a result, the flooding phenomenon can be reduced.
As described above, according to the present invention, it is possible to realize the fuel cell system 1 that can suppress the stable supply of power in the fuel cell 2 while reducing the flooding phenomenon.
Further, according to the fuel cell system 1 in the present embodiment, when the flooding phenomenon is eliminated as in the prior art, the flow rate of the oxidant gas supplied to the cathode electrode of the fuel cell 2 is compared with that during normal operation. Unlike the situation when the flooding phenomenon is reduced, the amount of oxidant supplied to the cathode electrode is the same as that during normal operation during the flooding reduction operation. Can be prevented from being discharged.
As a result, drying of the cathode catalyst layer 213 can be suppressed and the humidified state can be maintained, so that the oxidation of the catalyst in the cathode catalyst layer 213 can be suppressed, and therefore, deterioration of the catalyst can be suppressed. It becomes possible. Similarly, in the electrolyte membrane 211, drying of the membrane can be suppressed and a humidified state can be maintained, so that an increase in proton conduction resistance in the electrolyte membrane 211 can be suppressed.
Further, since the power value in the fuel cell 2 hardly changes as described above, it is possible to suppress the deterioration of the catalyst due to the growth of the particle size of the catalyst or the promotion of elution.
Therefore, it is possible to realize the fuel cell system 1 that can suppress a decrease in the power value in the fuel cell 2.

Further, according to the fuel cell system 1 in the present embodiment, the control unit 38 performs the above-described oxidant supply amount increase control and flow path opening degree decrease control, and the power value of the fuel cell 2 has reached a stable state. After the determination, the control unit 38 performs the oxidant supply amount decrease control and the channel opening degree increase control until the oxidant supply amount and the flow path opening degree of the pipe F4 become approximately the same as those during normal operation, and the fuel is supplied. The operation state of the battery system 1 may be shifted from the flooding phenomenon reduction operation to the normal operation.
Thereby, after the electric power value of the fuel cell 2 reaches a stable state, the control unit 38 can return the operation state of the fuel cell system 1 from the flooding phenomenon reduction operation to the normal operation.
For this reason, when the oxidant supply amount and the degree of openness of the pipe F4 are set as the optimum condition values for obtaining the fuel cell 2 having a high power value during the normal operation, the above-mentioned optimum in the flooding phenomenon reducing operation is set. It is possible to recover the power value of the fuel cell 2 that is lower than that during normal operation due to the change in the supply amount of the oxidant and the degree of openness of the pipe F4 from the condition values.
Therefore, it is possible to realize the fuel cell system 1 that can recover the power value of the fuel cell 2 while reducing the flooding phenomenon.

Further, according to the fuel cell system 1 of the present embodiment, the control unit 38 maintains the amount of oxidant supplied at the time of the flooding phenomenon reducing operation, while maintaining the amount of oxidant supplied and the degree of opening of the flow path. Increase control may be performed simultaneously.
As a result, when returning from the flooding phenomenon reducing operation to the normal operation, it is possible to maintain the stability of the pressure in the pipe F4, so that the power value in the fuel cell 2 is less likely to fluctuate. Thus, it is possible to suppress a decrease in the stable supply of electric power.
Therefore, it is possible to realize the fuel cell system 1 capable of recovering the power value of the fuel cell 2 and suppressing the deterioration of the stable power supply in the fuel cell 2 when returning from the flooding phenomenon reducing operation to the normal operation. .

In the above, when the flooding phenomenon reducing operation is performed for a long time, the oxidant is supplied to the cathode catalyst layer 213 for a long time, and therefore the cathode catalyst layer 213 is gradually dried. As a result, the potential of the cathode electrode rises, so that the catalyst in the cathode catalyst layer 213 is gradually oxidized, so that the catalyst is deteriorated and the power value of the fuel cell 2 may be lowered.
In contrast, according to the fuel cell system 1 of the present embodiment, first, the control unit 38 performs the above-described oxidant supply amount increase control and flow path opening degree decrease control so that the power value of the fuel cell 2 is in a stable state. After that, oxidant supply stop control and flow path opening degree increase control are performed. Thereafter, when the predetermined time T3 has elapsed, the control unit 38 determines that the oxidized catalyst has been sufficiently reduced, and thereafter, the supply amount of the oxidant and the degree of openness of the pipe F4 are the same as those during normal operation. It is possible to shift the operation state of the fuel cell system from the flooding phenomenon reduction operation to the normal operation by performing the oxidant supply amount increase control and the flow path opening degree decrease control until the same level is reached.
For this reason, since the supply of the oxidant is stopped during the oxidant supply stop operation, the active material supplied to the fuel cell 2 can be limited to only the methanol aqueous solution. As a result, the methanol aqueous solution supplied from the anode electrode side does not undergo a reduction reaction at the cathode electrode. Can do. As a result, the oxidized catalyst in the cathode catalyst layer 213 is reduced, so that the reduced power value in the fuel cell 2 can be recovered.
Therefore, the power value of the fuel cell 2 can be further recovered as compared with the case where the oxidant supply stop operation is not executed.
Further, in addition to the above-described effects, the flooding phenomenon reduction operation is performed when the supply amount of the oxidant and the degree of openness of the pipe F4 are set as optimum condition values for obtaining the fuel cell 2 having a high power value during normal operation At this time, it is possible to further recover the power value of the fuel cell 2 which is lower than that in the normal operation due to the change in the supply amount of the oxidant and the opening degree of the pipe F4 from the optimum condition values. It becomes possible.
Therefore, it is possible to realize the fuel cell system 1 capable of further recovering the power value of the fuel cell 2 while reducing the flooding phenomenon.

Further, in the above, if the oxidant supply stop control is performed with the degree of openness of the pipe F4 being small, air or water tends to remain in the cathode electrode, and the back pressure on the cathode electrode side becomes high. The amount of aqueous methanol solution penetrating from the cathode side to the cathode electrode side is suppressed, and the oxidized cathode catalyst layer 213 may not be sufficiently reduced, and the power value of the fuel cell 2 may not be sufficiently recovered. There is sex.
On the other hand, according to the fuel cell system 1 in the present embodiment, the control unit 38 simultaneously performs the oxidant supply stop control and the flow path opening degree increase control, or performs the oxidant supply stop control to increase the flow path opening degree. It can be done after the control.
As a result, it is possible to perform the oxidant supply stop control while maintaining a relatively high degree of openness of the flow path, so that it is possible to suppress air and water from remaining on the cathode electrode, and the back pressure on the cathode electrode side can be suppressed. Can be suppressed. Thus, the methanol aqueous solution supplied from the anode electrode side can be sufficiently permeated into the cathode electrode side, and the oxidized cathode catalyst layer 213 can be sufficiently reduced.
Therefore, it is possible to realize the fuel cell system 1 that can further recover the power value of the fuel cell 2.

Further, according to the fuel cell system 1 of the present embodiment, the control unit 38 maintains the same amount as that of the oxidant supplied during the flooding phenomenon reduction operation, and controls the oxidant supply amount increase control and the flow. The road opening degree reduction control may be performed simultaneously.
As a result, when returning from the oxidant supply stop operation to the normal operation, it is possible to maintain the stability of the pressure in the pipe F4, so that the fluctuation of the power value in the fuel cell 2 is less likely to occur. Therefore, it is possible to suppress a decrease in the stable power supply in 2.
Therefore, it is possible to realize the fuel cell system 1 capable of recovering the power value of the fuel cell 2 and capable of suppressing the stable power supply deterioration in the fuel cell 2 when returning from the oxidant supply stop operation to the normal operation. Become.

Further, according to the fuel cell system 1 in the present embodiment, the control unit 38 controls the flow path opening degree adjustment unit 35 until the flow path opening degree in the pipe F4 becomes maximum in the flow path opening degree increase control. May be.
As a result, it becomes possible to perform the oxidant supply stop control while maintaining a higher degree of openness of the flow path, so that it is possible to further suppress air and water remaining on the cathode electrode, and back pressure on the cathode electrode side Can be further suppressed. From this, the methanol aqueous solution supplied from the anode electrode side can be sufficiently permeated into the cathode electrode side, and the oxidized cathode catalyst layer 213 can be more sufficiently reduced.
Therefore, it is possible to realize the fuel cell system 1 that can further recover the power value of the fuel cell 2.

(Second Embodiment)
In the fuel cell system 1 described above, the cathode electrode in which the flooding phenomenon is relatively likely has been described. However, the flooding phenomenon may occur in the anode electrode for the following reason.
That is, a gas supply type fuel cell using a gaseous fuel such as hydrogen or methane as the active material for the anode electrode, or a gaseous fuel such as hydrogen obtained by converting liquid methanol used for the active material for the anode electrode with a reformer directly. In a fuel cell such as a reformed fuel cell supplied to the anode electrode, gas is supplied to both the anode electrode and the cathode electrode. Therefore, water generated at the cathode electrode due to the difference in osmotic pressure is generated in the anode electrode. As a result, the flooding phenomenon may occur in the anode electrode.
From this, the present inventors considered that the flooding phenomenon generated in the anode electrode can be solved by using the same principle as that of the fuel cell system 1, and found the fuel cell system 1B in the present embodiment. .
Therefore, next, referring to FIG. 6, a hydrogen type fuel cell system 1B (hereinafter simply referred to as a fuel cell) including a hydrogen type fuel cell 2B (hereinafter also simply referred to as a fuel cell 2B) that generates power using hydrogen as a fuel. The fuel cell system 1B in the present embodiment will be described in detail by taking as an example a system 1B). In addition, description is abbreviate | omitted about the structure similar to 1st Embodiment.

  FIG. 6 is a block diagram showing a fuel cell system according to the second embodiment of the present invention.

As shown in FIG. 6, the fuel cell system 1B in the present embodiment includes a fuel cell 2B, a gaseous fuel supply unit 31B, a fuel supply amount adjustment unit 34B, a flow path opening degree adjustment unit 35B, and a control unit 36B. And pipes F1B to F4B.
Here, as shown in FIG. 6, the fuel cell 2B, the gaseous fuel supply unit 31B, the fuel supply amount adjustment unit 34B, the flow path opening degree adjustment unit 35B, the control unit 36B, and the pipes F1B to F4B are It is housed in one housing.

  In the fuel cell 2B, unlike the fuel cell 2 described above, carbon monoxide is not generated during the oxidation reaction. Therefore, in the configuration of the membrane electrode assembly 21B in the fuel cell 2B, the electrode catalyst of the anode catalyst layer 212B is usually Although only platinum is used without using ruthenium having carbon monoxide poisoning resistance, the present invention is not limited to this, and the same fuel cell 2 as described above can be used.

The gaseous fuel supply unit 31B is a gaseous fuel container such as a high-pressure hydrogen gas cylinder and plays a role of supplying gaseous fuel such as hydrogen gas to the inlet 241 of the anode flow path.
Moreover, as shown in FIG. 6, the gaseous fuel supply part 31B is connected with the inlet 241 of the anode flow path via the piping F1B mentioned later.

The fuel supply amount adjustment unit 34B is, for example, an electric valve or the like, and plays a role of adjusting the supply amount of the gaseous fuel supplied from the gaseous fuel supply unit 31B and supplying it to the inlet 241 of the anode flow path.
Further, as shown in FIG. 6, the fuel supply amount adjusting unit 34B is provided in a pipe F1B described later.

The channel opening degree adjustment unit 35B is, for example, an electric valve or the like, and has a channel opening degree in the pipe F3B described later, that is, the size of the cross-sectional area shown along the direction perpendicular to the extending direction of the pipe F3B. It plays a role to coordinate.
In addition, as shown in FIG. 6, the flow path opening degree adjustment unit 35 </ b> B is provided in a pipe F <b> 3 </ b> B described later.

The control unit 36B is a microcomputer including, for example, a signal processing IC, a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like, and plays the following five roles.
First, it plays a role in determining whether or not the flooding phenomenon has occurred in the anode electrode during the operation of the fuel cell system 1B before the flooding phenomenon occurs (hereinafter referred to as normal operation). .
Secondly, it is determined whether or not the flooding phenomenon has been eliminated at the anode electrode during the operation of the fuel cell system 1B when the flooding phenomenon is being reduced (hereinafter referred to as flooding phenomenon reduction operation). Playing a role.
Thirdly, the fuel supply amount adjusting unit 34B is controlled based on the above determination result.
Fourth, it plays the role of controlling the flow path opening degree adjustment unit 35B based on the above determination result.
Fifth, it plays the role of driving and controlling the oxidant supply unit 33.
Further, the control unit 36B can increase the pressure in the pipe F3B at the same time without changing the supply amount of the gaseous fuel during the normal operation according to the following principle. That is, generally, when the supply amount of the gaseous fuel is increased while the degree of openness of the flow path of the pipe F4 is kept constant, the pressure in the pipe F3B increases, but at the same time, the supply amount of the gaseous fuel increases. However, when the degree of opening of the flow path of the pipe F3B is reduced, the supply amount of the gaseous fuel is reduced at the same time while increasing the pressure in the pipe F3B. For this reason, when the flow rate of the pipe F3B is decreased at the same time when the supply amount of the gaseous fuel is increased, the pressure in the pipe F3B is maintained while maintaining the same amount as the supply amount of the gaseous fuel during the normal operation. Can be raised.
Further, as shown in FIG. 5, the control unit 36B is electrically connected to the fuel cell 2B, the oxidant supply unit 33, the fuel supply amount adjustment unit 34B, and the flow path opening degree adjustment unit 35B.
The control unit 36B includes a voltage sensor (not shown) for detecting an output voltage and a current sensor (not shown) for detecting an output current between the fuel cell 2B and the control unit 36B. Is attached. The current sensor and the voltage sensor play a role of transmitting a power value calculated from each output value of the sensor to the control unit 36B.
Further, the control unit 36B determines whether or not the flooding phenomenon has occurred at the anode electrode, or has reached the value of the gaseous fuel supply amount and the degree of openness of the pipe F3B as the optimum conditions in the flooding phenomenon reduction operation No, a power value information storage unit (not shown) is provided as a storage device for storing various parameter information necessary for determining whether the flooding phenomenon has been resolved. Thus, the control unit 36B can determine whether or not a flooding phenomenon has occurred at the anode pole.
In addition, when the control unit 36B shifts from the normal operation to the flooding phenomenon reduction operation, the fuel supply amount is set as the control data value so that the control unit 36B can maintain the same amount as the supply amount of the gaseous fuel at the normal operation. A table (hereinafter referred to as control) in which the value of the gaseous fuel supply amount in the gaseous fuel supply unit 31B adjusted by the adjustment unit 34B and the value of the channel opening degree of the pipe F3B adjusted by the channel opening degree adjustment unit 35B are described. (Referred to as an information table) has a pre-recorded control information storage unit (not shown). Here, the control data value is set in advance to an optimum value for eliminating the flooding phenomenon. Further, the control information table is changed in accordance with the operating conditions of the fuel cell 2B necessary for obtaining the optimum power value of the fuel cell 2B, such as the temperature of the fuel cell 2B and the concentration of the gaseous fuel, etc. A plurality of each is provided for each operating condition. Therefore, after determining that the flooding phenomenon has occurred in the anode electrode, the control unit 36B confirms the operating conditions of the fuel cell 2B, and among the plurality of control information tables, controls optimal for the operating conditions of the fuel cell 2B. An information table is selected from the control information storage unit. Then, the control unit 36B refers to the supply amount U1 ′ of the gaseous fuel and the flow path opening degree V1 ′ of the pipe F3B as the control data values described in the selected control information table, and until these values are reached. The fuel supply amount adjusting unit 34B and the flow path opening degree adjusting unit 35B can be controlled.

The pipes F1B, F3B, and F4B play the role of transporting the gas described above as flow paths for various gases in the fuel cell system 1B, and are provided as follows.
The pipe F1B plays a role of supplying the gaseous fuel in the gaseous fuel supply unit 31B to the inlet 241 of the anode channel, and is connected to the gaseous fuel supply unit 31B and the inlet 241 of the anode channel.
The pipe F3B is an exhaust gas discharged from the anode channel outlet 242 for the purpose of reusing the exhaust gas discharged from the anode channel outlet 242 as gaseous fuel supplied to the anode channel inlet 241. Is supplied to the pipe F1B, and is connected to the outlet 242 of the anode flow path and the pipe F1B.
The pipe F4B is an exhaust gas discharged from the cathode channel outlet 252 for the purpose of reusing the exhaust gas discharged from the cathode channel outlet 252 as an oxidant supplied to the cathode channel inlet 251. Is supplied to the pipe F2, and is connected to the cathode flow path outlet 252 and the pipe F2.

  The fuel cell system 1B is configured by the above structures. In the above configuration, the oxidant supply unit 33 uses an air pump such as an air blower or an air compressor as in the first embodiment, but in this embodiment, the oxidant supply unit 33 is not limited to the above air pump, Instead of the air pump, for example, a gas oxidizer container such as a high-pressure oxygen gas cylinder may be used.

(Operating principle of fuel cell system)
With the above configuration, the fuel cell system 1B can supply the electric power generated from the fuel cell 2B to the external load 41 according to the following principle.
First, the hydrogen supplied from the gaseous fuel supply unit 31B is supplied to the inlet 241 of the anode flow path, then passes through the anode flow path 26 of the anode separator 24 and permeates the anode gas diffusion layer 214, and then the anode catalyst. Layer 212 is reached.
Next, only after hydrogen reaches the anode catalyst layer 212, as shown in the following formula (1), hydrogen causes an oxidation reaction to release electrons and generate protons.
H ₂ → 2H ⁺ + 2e ⁻ (1)
Next, the generated protons move from the anode catalyst layer 212 to the surface of the electrolyte membrane 211, pass through the inside of the electrolyte membrane 211, and are supplied to the cathode catalyst layer 213 before long.
Further, the generated electrons are supplied to the cathode catalyst layer 213 in the order of “1” to “9” below.
“1” anode catalyst layer 212, “2” anode gas diffusion layer 214, “3” anode separator 24, “4” anode current collector 22, “5” external load 41, “6” cathode current collector 23, “ 7 ”cathode separator 25,“ 8 ”cathode gas diffusion layer 215, and“ 9 ”cathode catalyst layer 213.
Next, after the oxidant supplied from the oxidant supply unit 33 is supplied to the inlet 251 of the cathode flow path, it passes through the cathode flow path 27 of the cathode separator 25 and permeates the cathode gas diffusion layer 215. The cathode catalyst layer 213 is reached.
In addition, the proton supplied to the cathode catalyst layer 213 causes a reduction reaction with the above oxidizing agent to generate water.
1 / 2O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
By the above oxidation reaction and reduction reaction, a current flows to the fuel cell 2B, and it becomes possible to supply electric power from the fuel cell 2 to the external load 41.

  Next, the operation of the control unit 36B in this embodiment when shifting from the normal operation to the flooding phenomenon reduction operation will be described in detail with reference to FIG. 7 based on the following steps S201 to S210.

  FIG. 7 is a flowchart showing a control procedure of normal operation and flooding phenomenon reduction operation in the control unit according to the second embodiment of the present invention.

First, the fuel cell system 1B is activated and current is supplied to the fuel cell 2B (step S201).
Next, simultaneously with the start of energization of the fuel cell 2B, the monitoring of the power value in the fuel cell 2B is started, and after setting the time interval Δt1 ′ from the monitoring start time t _a ′ to the predetermined time t _b ′, this time In the interval Δt1 ′, the voltage sensor detects the average output voltage of the fuel cell 2B and the current sensor detects the average output current of the fuel cell 2B, and then the average power value W1 of the fuel cell 2B is determined from the output values of both sensors. '(Hereinafter defined as power value W1') is calculated, and the power value W1 'is stored in a power value information storage unit (not shown) included in the control unit 36B and set (step). S202).
Next, the power value of the fuel cell 2B is constantly monitored, and after setting the time interval Δt2 ′ from the predetermined time t _b ′ to the monitoring end time t _c ′, the fuel cell 2B in the time interval Δt2 ′ is set. Average power value W2 ′ (W1 ′> W2 ′, hereinafter defined as power value W2 ′) is acquired at an arbitrary time (step S203).
Next, a difference ΔW ′ between the power value W1 ′ and the power value W2 ′ is calculated (step S204).
Next, it is determined whether or not the difference ΔW ′ between the power value W1 ′ and the power value W2 ′ is equal to or greater than a predetermined value S1 ′ (step S205).
If the control unit 36B determines in step S205 that the difference ΔW ′ between the power value W1 ′ and the power value W2 ′ is not equal to or greater than the predetermined value S1 ′ (in the case of NO), the fuel cell 2B It is determined that the power value is not significantly reduced and no flooding phenomenon has occurred, and the process returns to step S203 and is repeatedly calculated until step S204. On the other hand, when the control unit 36B determines that the difference ΔW ′ between the power value W1 ′ and the power value W2 ′ is equal to or greater than the predetermined value S1 ′ (in the case of YES), the power value of the fuel cell 2B is It is relatively low and it is determined that a flooding phenomenon has occurred. In this case, the control unit 36B confirms the operating conditions of the fuel cell 2B such as the temperature of the fuel cell 2B and the concentration of the gaseous fuel, and among the plurality of control information tables, the optimal control information for the operating conditions of the fuel cell 2B. A table is selected from the control information storage unit (step S206).
Next, the control unit 36B controls each control data value of the gaseous fuel supply amount and the channel opening degree described in the selected control information table (hereinafter, this value is referred to as the gaseous fuel supply amount U1 ′, the channel Reference is made to “opening degree V1 ′” (step S207).
Next, the control unit 36B generates a fuel supply amount increase control signal for controlling the fuel supply amount adjustment unit 34B so that the gaseous fuel supply amount increases until the gaseous fuel supply amount U1 ′ referred to above is reached. Further, a flow path opening degree decrease control signal for controlling the flow path opening degree adjusting unit 35B is generated so that the flow path opening degree of the pipe F3B decreases until the flow path opening degree V1 ′ referred to above is reached. Thereafter, the control unit 36B transmits the fuel supply amount increase control signal generated above to the fuel supply amount adjustment unit 34B, and at the same time transmits a flow path opening degree decrease control signal to the flow path opening degree adjustment unit 35B (step S31). S208).
Next, based on the fuel supply amount increase control signal transmitted from the control unit 36B in step S208, the fuel supply amount adjustment unit 34B refers to the above from the gaseous fuel supply amount U0 ′ already set during the normal operation. Adjustment (fuel supply amount increase control) for increasing the gaseous fuel supply amount in the gaseous fuel supply unit 31B is executed until the gaseous fuel supply amount U1 ′ is reached. Furthermore, the flow rate opening degree adjustment unit 35B is based on the flow rate opening degree reduction control signal transmitted from the control unit 36B in step S208 while maintaining the same amount as the amount of gaseous fuel supplied during normal operation. Adjustment to reduce the flow rate of the pipe F3B until the flow rate V1 ′ of the pipe F3B referred to above is reached from the flow rate V0 ′ of the pipe F3B already set during normal operation (flow path open) (Degree reduction control) is executed simultaneously with the fuel supply amount increase control (step S209). Finally, after executing the fuel supply amount increase control and the flow path opening degree decrease control in step S209, a predetermined time T1 ′ set in advance that can be determined from an empirical rule when the power value of the fuel cell 2B reaches a stable state is obtained. After the elapse, the control unit 36B determines that the power value of the fuel cell 2B has reached a stable state (step S210).
By shifting from the normal operation to the flooding phenomenon reducing operation by the above procedure, the control unit 36B can reduce the flooding phenomenon while suppressing the stable supply of power in the fuel cell 2B.
Further, in the above description, the supply amount of the gaseous fuel during the flooding phenomenon reducing operation is maintained at the same level as the supply amount of the gaseous fuel during the normal operation. Here, the amount equivalent to the amount of gaseous fuel supplied during normal operation means that the relationship between the value of gaseous fuel supplied during operation with reduced flooding phenomenon and the amount of gaseous fuel supplied during normal operation is as follows: It means that it may be street. That is, the value of the gaseous fuel supply amount during the flooding phenomenon reduction operation is not limited to the same value as the gas fuel supply amount value during the normal operation. For example, the value of the gaseous fuel supply amount during the flooding phenomenon reduction operation is It may be a value including an error of up to ± 3.0% with respect to the value of the supply amount of the gaseous fuel during normal operation.
As for the time interval Δt1 ′, the time interval Δt2 ′, and the predetermined value S1 ′, values desired by the user can be used. However, the predetermined value S1 ′ can be used after the start of energization of the fuel cell system. It is preferable to set a value that represents the rate of decrease in the power value of the fuel cell 2B that has decreased from the occurrence of the flooding phenomenon to the occurrence of the flooding phenomenon. As this specific value, for example, among the values calculated from the following equation (4), It is more preferable to use 3 to 6 (%) in advance. However, in the following formula (4), a is the power value (mW / cm ² ) of the fuel cell immediately after the start of energization of the fuel cell system, and b is the fuel measured after 1 hour from the start of energization of the fuel cell system. It is the electric power value (mW / cm ² ) of the battery.

Further, when the supply amount of gaseous fuel and the opening degree of the flow path of the pipe F3B are set as the optimum condition values for obtaining the fuel cell 2B having a high power value during normal operation, when the flooding phenomenon reduction operation is performed, Since the supply amount of gaseous fuel and the degree of opening of the flow path of the pipe F3B are changed from the optimum condition values, the power value of the fuel cell 2B may be lower than that during normal operation. Therefore, in this case, in order to obtain as high a power value as possible for the fuel cell 2B, the operation state of the fuel cell system 1B is changed to a flooding phenomenon-reducing operation after a predetermined time has elapsed since the start of the flooding phenomenon. It is necessary to return to normal operation.
Therefore, next, the operation of the control unit 36B in the present embodiment when returning from the flooding phenomenon reducing operation to the normal operation will be described in detail using FIG. 8 based on the following steps S211 to S213.

  FIG. 8 is a flowchart showing the control procedure of the flooding phenomenon reducing operation and the normal operation in the control unit according to the second embodiment of the present invention.

First, through the above step S210, the control unit 36B, until the supply amount of the gaseous fuel after shifting to the normal operation becomes the same amount as the supply amount of the gaseous fuel in the normal operation before the flooding phenomenon reducing operation, A fuel supply amount decrease control signal for controlling the fuel supply amount adjustment unit 34B is generated so that the supply amount of the gaseous fuel decreases. Further, the degree of openness of the pipe F3B increases until the degree of openness of the pipe F3B after the transition to the normal operation becomes approximately the same as the degree of openness of the pipe F3B during the normal operation before the flooding phenomenon reducing operation. In this manner, a flow path opening degree increase control signal for controlling the flow path opening degree adjusting unit 35B is generated. Thereafter, the control unit 36B transmits the generated fuel supply amount decrease control signal to the fuel supply amount adjustment unit 34B, and at the same time transmits a flow path opening degree increase control signal to the flow path opening degree adjustment unit 35B (step S211). .
Finally, based on the fuel supply amount decrease control signal transmitted from the control unit 36B in step S211, the fuel supply amount adjustment unit 34B operates to reduce the flooding phenomenon after the shift to the normal operation. Adjustment (fuel supply amount reduction control) is performed to reduce the supply amount of the gaseous fuel in the gaseous fuel supply unit 31B until the supply amount is about the same as the supply amount U0 ′ of the gaseous fuel in the previous normal operation. Furthermore, the flow rate opening degree adjusting unit 35B is maintained based on the flow rate opening degree increasing control signal transmitted from the control unit 36B in step S211 while maintaining the same amount as the supply amount of the gaseous fuel during the flooding phenomenon reducing operation. Is the degree of openness of the pipe F3B until the degree of openness of the pipe F3B after the transition to the normal operation becomes approximately the same as the degree of openness V0 ′ of the pipe F3B during the normal operation before the flooding phenomenon reducing operation. Adjustment for increasing the flow rate (flow path opening degree increase control) is executed (step S212). As a result, the supply amount of the gaseous fuel and the degree of opening of the flow path of the pipe F3B are the same as those in the normal operation before the flooding phenomenon reducing operation.
Finally, after executing the fuel supply amount decrease control and the flow path opening degree increase control in step S212, a predetermined time T2 ′ set in advance that can be determined from an empirical rule when the power value of the fuel cell 2B reaches a stable state is obtained. After the elapse, the control unit 36B determines that the power value of the fuel cell 2B has reached a stable state (step S213).
As described above, the operation state of the fuel cell system 1B returns from the flooding phenomenon reduction operation to the normal operation.
Further, in the above, the supply amount of the gaseous fuel after the shift to the normal operation is maintained at the same level as the supply amount of the gaseous fuel at the time of the flooding phenomenon reducing operation. Here, the amount of gaseous fuel supplied during the flooding reduction operation is the same as the amount of gaseous fuel supplied during the normal operation and the amount of gaseous fuel supplied during the flooding reduction operation. This means that the relationship may be as follows. That is, the value of the gaseous fuel supply amount after the transition to the normal operation is not limited to the same value as the value of the gaseous fuel supply amount during the flooding reduction operation, for example, the supply of the gaseous fuel after the transition to the normal operation The amount value may be a value including an error of up to ± 3.0% with respect to the value of the supply amount of the gaseous fuel during the flooding phenomenon reduction operation.
In addition, the fuel supply amount decrease control in step S212 may be performed simultaneously with the flow rate opening degree increase control while maintaining the same amount as the gaseous fuel supply amount during the flooding phenomenon reducing operation, or the flow channel open rate control. However, it is possible to return to the normal operation from the flooding phenomenon reducing operation while maintaining the stability of the pressure in the pipe F3B. It is preferable to carry out simultaneously with the flow path opening degree increase control while maintaining the same amount as the supply amount of the gaseous fuel.
Further, after step S213, a series of steps from step S203 to step S213 may be performed once or a plurality of times. Here, the number of times of performing the series of steps S203 to S213 performed after step S213 is not particularly limited and may be one or more times, but is preferably performed every time a flooding phenomenon occurs.
Further, in the present embodiment, if there is a circumstance that the fuel cell 2B can be operated with the power value of the fuel cell 2B obtained during the flooding phenomenon reducing operation, such as when the operation time of the fuel cell system 1B is short, the above Steps S211 to S213 are not necessarily performed, and the fuel cell system 1B may be operated in a flooding phenomenon reduction operation state throughout the operation period of the fuel cell system 1B.

  In the control unit 36B, the parameters used for the determination are not limited to the power values W1 ′, W2 ′, and W3 ′ of the fuel cell 2B, and other parameters may be used. For example, the fuel cell 2B Instead of the power value, the amount of drainage at the outlet 242 of the anode channel may be used. Here, when the amount of drainage is used as a parameter used in the above determination, the amount of drainage is measured after measuring the amount of drainage using a flow sensor for water instead of the current sensor and the voltage sensor used outside the control unit 36B. Can be used as a parameter by transmitting to the control unit 36B.

(Operation effect of the fuel cell system 1B in the second embodiment)
Next, the effect of the fuel cell system 1B in this embodiment is demonstrated.

In conventional fuel cells using gaseous fuel, gas is supplied to both the anode and cathode, so water generated at the cathode penetrates into the anode due to the difference in osmotic pressure. For this reason, there is a problem that the flooding phenomenon may occur in the anode electrode as in the cathode electrode.
On the other hand, according to the fuel cell system 1B in the present embodiment, when it is determined that the flooding phenomenon has occurred in the anode electrode, the fuel supply amount adjustment unit 34B is controlled so that the supply amount of gaseous fuel increases. The fuel supply amount increase control is performed, and the flow rate opening degree adjusting unit 35B is controlled so that the flow rate degree of the pipe F3B is reduced while maintaining the same amount as the gaseous fuel supply amount during normal operation. A control unit 36B is provided that performs the flow rate opening degree decrease control simultaneously with the fuel supply amount increase control and shifts the operation state of the fuel cell system 1B from the normal operation to the flooding phenomenon reduction operation.
As a result, when the flooding phenomenon occurs in the anode electrode, the control unit 36B performs the above-described fuel supply amount increase control, and further maintains the same amount as the supply amount of the gaseous fuel during the normal operation. The flow rate reduction control of the fuel cell is performed simultaneously with the fuel supply increase control, and the operation state of the fuel cell system is shifted from the normal operation to the flooding phenomenon reduction operation that reduces the flooding phenomenon. However, the supply amount of the gaseous fuel does not decrease from the normal operation time, and can maintain the same amount as the supply amount of the gaseous fuel during the normal operation.
For this reason, in the present invention, since the supply amount of the gaseous fuel is not increased for the purpose of reducing the flooding phenomenon, the oxidation reaction in the anode catalyst layer 212 accompanying the increase in the supply amount of the gaseous fuel is suppressed.
For this reason, the amount of water generated at the cathode electrode and permeating into the anode catalyst layer 212 due to the difference in osmotic pressure can be maintained at the same level as during normal operation during the flooding reduction operation. Therefore, it is possible to suppress the amount of excess water produced at the anode electrode.
As a result, the pipe F3B is less likely to be blocked by the excessively generated water, so that the excessively generated water and the gaseous fuel are less likely to stay in the pipe F3B. It becomes possible to do.
Accordingly, when reducing the flooding phenomenon, it is possible to maintain the stability of the pressure in the pipe F3B, so that the power value in the fuel cell 2B is less likely to fluctuate. It is possible to suppress the deterioration of property.
Further, according to the present invention, since the control unit 36B performs the fuel supply amount increase control described above, the pressure in the pipe F3B increases, and as a result, the flooding phenomenon can be reduced.
As described above, according to the present invention, it is possible to realize the fuel cell system 1B that can suppress the stable supply of power in the fuel cell 2B while reducing the flooding phenomenon.
Further, according to the fuel cell system 1B in the present embodiment, the amount of gaseous fuel supplied to the anode electrode during the operation for reducing the flooding phenomenon is the same as that during normal operation. Excessive water permeation into the anode electrode can be suppressed.
As a result, drying of the anode catalyst layer 212 can be suppressed and a humidified state can be maintained, so that oxidation of the catalyst in the anode catalyst layer 212 can be suppressed, so that deterioration of the catalyst can be suppressed. It becomes possible. Similarly, the electrolyte membrane 211 can be prevented from being dried and kept in a humidified state, so that an increase in proton conduction resistance in the electrolyte membrane 211 can be suppressed.
Further, since the power value in the fuel cell 2B hardly changes due to the above, it is possible to suppress the deterioration of the catalyst due to the growth of the particle size of the catalyst or the promotion of elution.
Therefore, it is possible to realize a fuel cell system 1B that can suppress a decrease in power value in the fuel cell 2B.

Further, according to the fuel cell system 1B in the present embodiment, the control unit 36B performs the fuel supply amount increase control and the flow path opening degree decrease control described above, and determines that the power value of the fuel cell 2B has reached a stable state. After that, the control unit 36B performs the fuel supply amount decrease control and the channel opening degree increase control until the supply amount of the gaseous fuel and the opening degree of the pipe F3B become approximately the same as those during normal operation. The operation state 1B may be shifted from the flooding phenomenon reduction operation to the normal operation.
Thereby, after the power value of the fuel cell 2B reaches a stable state, the control unit 36B can return the operation state of the fuel cell system 1B from the flooding phenomenon reduction operation to the normal operation.
For this reason, when the supply amount of gaseous fuel and the opening degree of the flow path of the pipe F3B are set as the optimum condition values for obtaining the fuel cell 2B having a high power value during the normal operation, the above-mentioned optimum in the flooding phenomenon reducing operation is set. It is possible to recover the power value of the fuel cell 2B, which is lower than that during normal operation, due to the change in the supply amount of gaseous fuel and the degree of opening of the flow path of the pipe F3B from the condition values.
Therefore, it is possible to realize the fuel cell system 1B that can recover the power value of the fuel cell 2B while reducing the flooding phenomenon.

Further, according to the fuel cell system 1B in the present embodiment, the control unit 36B maintains the amount of oxidant supplied during the flooding phenomenon reducing operation while maintaining the amount of fuel supply reduction and increasing the degree of openness of the flow path. Control may be performed simultaneously.
As a result, when returning from the flooding phenomenon reducing operation to the normal operation, it is possible to maintain the stability of the pressure in the pipe F3B, and therefore the power value in the fuel cell 2B is less likely to fluctuate. It is possible to suppress a decrease in the stable supply of electric power.
Accordingly, it is possible to realize the fuel cell system 1B capable of recovering the power value of the fuel cell 2B and suppressing the decrease in stable power supply in the fuel cell 2B when returning from the flooding phenomenon reducing operation to the normal operation. .

  “Fuel cell system 1” and “fuel cell system 1B” in the embodiment of the present invention correspond to an example of “fuel cell system” in the present invention, and “fuel cell 2” and “fuel” in the embodiment of the present invention. The “battery 2B” corresponds to an example of the “fuel cell” in the present invention, and the “cathode catalyst layer 213” and the “cathode gas diffusion layer 215” in the embodiment of the present invention correspond to an example of the “cathode electrode” in the present invention. The “oxidant supply unit 33” in the embodiment of the present invention corresponds to an example of the “oxidant supply unit” in the present invention, and the “oxidant supply amount adjusting unit 34” in the embodiment of the present invention is “ This corresponds to an example of the “oxidant supply amount adjusting unit”, and “pipe F4” in the embodiment of the present invention corresponds to an example of “oxidant discharge flow path unit” in the present invention. The “channel opening degree adjusting unit 35” and the “channel opening degree adjusting unit 35B” in this example correspond to an example of the “channel opening degree adjusting unit” in the present invention, and the “control unit 38” in the embodiment of the present invention and The “control unit 36B” corresponds to an example of the “control unit” in the present invention, and the “anode catalyst layer 212” and the “anode gas diffusion layer 214” in the embodiment of the present invention are examples of the “anode electrode” in the present invention. The “gaseous fuel supply unit 31B” in the embodiment of the present invention corresponds to an example of the “gaseous fuel supply unit” in the present invention, and the “fuel supply amount adjustment unit 34B” in the embodiment of the present invention corresponds to the present invention. This corresponds to an example of a “fuel supply amount adjustment unit”, and “piping F3B” in the embodiment of the present invention corresponds to an example of a “fuel discharge flow path unit” in the present invention.

Further, the fuel cell system 1 and the fuel cell 2 in the first embodiment of the present invention described above are not limited to the direct methanol fuel cell system and the direct methanol fuel cell, respectively. For example, hydrogen, hydrazine, ethanol The present invention can also be applied to other types of fuel cells such as an anionic fuel cell using the above as fuel.
Further, the fuel cell system 1B and the fuel cell 2B according to the second embodiment of the present invention described above are not limited to the hydrogen type fuel cell system and the hydrogen type fuel cell, respectively. Direct gas supply type fuel cell using gaseous fuel such as methane, and reformed fuel that supplies gaseous fuel such as hydrogen obtained by converting liquid methanol used as the active material of the anode electrode by a reformer directly to the anode electrode It can also be applied to fuel cells such as batteries.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  Below, the effect of the present invention was confirmed by examples and comparative examples that further embody the present invention. The following examples and comparative examples are for confirming the effect of suppressing the performance degradation of the fuel cell system according to the first embodiment of the present invention described above.

<Example 1>
As the polymer electrolyte membrane, a polymer electrolyte membrane made of perfluorocarbon sulfonic acid having a thickness of 125 μm (Nafion (trade name, registered trademark) manufactured by DuPont, USA) was prepared. Next, on one main surface of the polymer electrolyte membrane, a catalyst ink for forming an anode catalyst layer (an isopropyl alcohol (IPA) solution to which a perfluorinated ion exchange polymer is added, a platinum-ruthenium catalyst (platinum / ruthenium and A conductive carbon particle having a mass ratio of 1: 1) dispersed therein was provided by printing. On the other main surface of the polymer electrolyte membrane, a catalyst for forming a cathode catalyst layer (an isopropyl alcohol (IPA) solution with a perfluorinated ion exchange polymer added to a platinum catalyst (platinum supported amount of 70 (Mass%) was dispersed by printing.
Next, the polymer electrolyte membrane printed with the catalyst ink as described above is heated at 130 ° C. for 1 hour using an oven to form an anode catalyst layer and a cathode catalyst layer, and then the carbon paper is formed on the anode catalyst layer. The anode separator and the anode current collector were laminated in this order, and the carbon paper, the cathode separator, and the cathode current collector were laminated in this order on the cathode catalyst layer to produce a single cell fuel cell.
Next, 75 layers of single-cell fuel cells are stacked in the upper direction with respect to FIG. 1, and each of the uppermost and lowermost fuel cells is pressed with two resin plates from the vertical direction with respect to FIG. After that, the fuel cell and the resin plate were mechanically fixed with bolts to produce a multilayer type fuel cell.

Next, the multilayer fuel cell produced as described above was connected to a fuel tank and an oxidant supply unit via each pipe, and further connected to an external load via wiring.
Next, a fuel tank was prepared, and the fuel tank was connected to an external fuel tank and a circulation tank via each pipe.
Next, a liquid pump was prepared and connected to each of the following pipes (1) to (3).
(1) A pipe connecting the fuel tank and the inlet of the anode passage of the fuel cell (2) A pipe connecting the fuel tank and the circulation tank (3) A pipe connecting the fuel tank and the external fuel tank An air pump equipped with a panel was prepared and connected to a pipe connecting the fuel tank and the cathode channel inlet of the fuel cell.
Next, an electric valve was prepared and connected to a pipe connecting the fuel tank and the outlet of the cathode passage of the fuel cell.
Next, a microcomputer was prepared as a control unit, connected to the above-described various liquid pumps, operation panel, and electric valve, and further connected to a fuel cell via a current sensor and a voltage sensor.
Of the above components, the components other than the external fuel tank and the external load are housed in one housing, and the external fuel tank and the external load are installed outside the housing. A fuel cell system was prepared. The following tests were conducted using the above test samples.

≪Performance measurement test of fuel cell system≫
In the prepared fuel cell system, when 1 mol / L methanol aqueous solution (methanol concentration 3.0%) was supplied to the anode electrode and 0.4 L / min air (atmospheric oxygen concentration 21%) was supplied to the cathode electrode. The power value [mW / cm ² ] of was continuously measured. From this measurement result, as the performance of the fuel cell system, the power value decrease rate X representing the decrease rate of the power value of the fuel cell 2B that has decreased from the start of energization of the fuel cell system until the occurrence of the flooding phenomenon is expressed as follows ( 5) Calculated from the equation. However, in the following formula (5), a is the power value (mW / cm ² ) of the fuel cell after the start of energization of the fuel cell system, and b is the fuel measured after 1 hour from the start of energization of the fuel cell system. This is the battery power value (mW / cm ² ).

Further, as the performance of the fuel cell system, variation from the average power value of the fuel cell (hereinafter, simply defined as the average power value) measured from 12 minutes after the start of the fuel cell system until 1 hour has elapsed. The standard deviation σ of the power value of the fuel cell representing the size was calculated from the following equation (6). However, in the following formula (6), n is the number of measured power values, x_i is the power value (mW / cm ² ) of the fuel cell at one measurement point, and μ is 12 minutes after the start of the fuel cell system. It is an average power value (mW / cm ² ) of the fuel cell measured after 1 hour from the end.

Thereby, the suppression effect of the performance degradation of the fuel cell system was evaluated from the results of the power value reduction rate and the standard deviation of the power value.
In Example 1, the fuel cell system was operated under the following operating conditions.
That is, the operation time was 1 hour. Further, the control unit determines that a flooding phenomenon has occurred at the cathode electrode 6 minutes after the start of operation, and then the pressure of the air supplied to the inlet of the cathode electrode increases by 1 kPa after 1 hour from the start of operation. Similarly, the control signal is transmitted to the electric valve, and the cross section shown along the direction perpendicular to the extending direction of the pipe connecting the fuel tank and the inlet of the cathode flow path of the fuel cell closes the electric valve. The motorized valve was controlled to close gradually until an area of about 50% of the previous cross-sectional area was reached. At the same time, the control unit transmits a control signal to the operation panel of the air pump to control the output of the air pump to increase. By the above two controls, the air supply amount was adjusted so as to keep the same state from the state before the flooding phenomenon occurred. The measurement results are shown in FIG.

  FIG. 9 is a graph showing the relationship between the power value of the fuel cell and the elapsed time after startup of the fuel cell system in the example of the present invention.

<Comparative Example 1>
As a comparative example of Example 1, test samples were prepared in the same manner as in Example 1 except that the electric valve was not controlled and the output of the air pump was not controlled under the above operating conditions. A power value measurement test was conducted. The measurement results are shown in FIG.

<Comparative example 2>
As a comparative example of Example 1, test samples were prepared in the same manner as in Example 1 except that the output of the air pump was not controlled under the above operating conditions, and a power value measurement test was performed. The measurement results are shown in FIG.

<Comparative Example 3>
As a comparative example of Example 1, test samples were respectively produced in the same manner as in Example 1 except that the electric valve was not controlled under the above operating conditions, and a power value measurement test was performed. The measurement results are shown in FIG.

Moreover, as shown in FIG. 9 and Table 1, about Example 1, the electric power value reduction rate was the lowest compared with Comparative Examples 1-3. Moreover, as shown in FIG. 9 and Table 2, in Example 1, the standard deviation of the power value was the smallest as compared with Comparative Examples 1 to 3.
As mentioned above, about Example 1, it turned out that the suppression effect of the performance fall of a fuel cell system is excellent.
On the other hand, as shown in FIG. 9 and Table 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 had a higher power value reduction rate than Example 1. Further, as shown in FIG. 9 and Table 2, in Comparative Example 1, Comparative Example 2, and Comparative Example 3, the standard deviation of the power value was larger than that in Example 1.
From the above, it was found that Comparative Example 1, Comparative Example 2, and Comparative Example 3 were inferior in the effect of suppressing the performance degradation of the fuel cell system as compared with Example 1.

Here, it is considered that the above result was obtained for the following reason.
That is, for the fuel cell system according to Example 1, the control unit simultaneously performed the following controls 1 and 2 while maintaining the same state as the air supply amount during normal operation before the flooding phenomenon occurred. This makes it possible to maintain the stability of the pressure in the pipe connecting the fuel tank and the outlet of the cathode flow path of the fuel cell, and this is because the fluctuation of the power value in the fuel cell is less likely to occur. This is probably because of this.
Here, as the control 1, when it is determined that the flooding phenomenon has occurred, the control unit performs control to increase the output of the air pump so that the supply amount of air in the air pump increases.
Further, as the control 2, it can be mentioned that the control unit performs control to close the electric valve provided in the pipe connecting the fuel tank and the outlet of the cathode flow path of the fuel cell.
On the other hand, in the fuel cell system according to Comparative Example 1, the power value decrease rate is higher than that in Example 1, but this can eliminate the flooding phenomenon because the control 1 and the control 2 are not performed. This is probably because the supply of air to the cathode catalyst layer is hindered by the generated excessively generated water, and the reduction reaction of the fuel cell is not sufficiently performed, and the power value is significantly reduced. Further, the standard deviation of the electric power value is higher than that of the first embodiment. This is because the flooding phenomenon cannot be eliminated because the control 1 and the control 2 are not performed, and the cathode flow of the fuel tank and the fuel cell is not. This is probably because the stability of the pressure in the pipe connecting the outlet of the road cannot be maintained, and the fluctuation of the power value in the fuel cell could not be suppressed.
Further, in the fuel cell system according to Comparative Example 2, the power value reduction rate is higher than that in Example 1. This is because the control 1 is not performed, so that the cathode flow of the fuel tank and the fuel cell is reduced. In the pipe connecting the outlet of the road, the pressure loss increased with time. As a result, the amount of air supplied decreases with time, and this is considered to be due to the fact that the reduction reaction of the fuel cell is not sufficiently performed and the power value is significantly reduced. In addition, the standard deviation of the power value is higher than that of the first embodiment. This is because the flooding phenomenon cannot be sufficiently eliminated because the control 1 is not performed, and the fuel tank and the fuel cell cathode flow path. This is because the stability of the pressure in the pipe connecting the outlet of the fuel cell cannot be maintained, and the fluctuation of the power value in the fuel cell cannot be suppressed.
Moreover, although the electric power value decreasing rate is higher than Example 1 about the fuel cell system which concerns on the comparative example 3, this is because the said control 2 was not performed, but immediately after the driving | operation start of a fuel cell system. Since the amount of air supplied to the cathode electrode increases with time and the reduction reaction of the fuel cell is further promoted, the oxidation / reduction reaction of the fuel cell is further promoted. The power value increased rapidly within a few minutes immediately after the start of operation. However, since the reduction reaction of the fuel cell is further promoted, the amount of generated excess water is increased, and the reduction reaction of the fuel cell is suppressed. it is conceivable that. In addition, the standard deviation of the power value is higher than that of the first embodiment. This is because the amount of air supplied to the cathode electrode increases with time because the control 2 is not performed. The reduction reaction of the battery is further promoted and the amount of excess generated water is increased, so that the pipe connecting the fuel tank and the outlet of the cathode flow path of the fuel cell is likely to be blocked by the excess generated water. From this, it is considered that the stability of the pressure in the pipe cannot be maintained, and the fluctuation of the power value in the fuel cell cannot be suppressed.

  As described above, in the fuel cell system according to Example 1, the effect of suppressing the performance degradation of the fuel cell system was confirmed.

DESCRIPTION OF SYMBOLS 1,1B ... Fuel cell system 2,2B ... Fuel cell 21 ... Membrane electrode assembly 211 ... Electrolyte membrane 212 ... Anode catalyst layer 213 ... Cathode catalyst layer 214 ... Anode gas diffusion layer 215 ... Cathode gas diffusion layer 216A, 216B ... Reinforcement Layer 22 ... Anode current collector 23 ... Cathode current collector 24 ... Anode separator 241 ... Anode flow path inlet 242 ... Anode flow path outlet 25 ... Cathode separator 251 ... Cathode flow path inlet 252 ... Cathode flow path outlet 26 ... Anode channel 27 ... Cathode channel 28, 29 ... Gasket 31 ... Fuel tank 31B ... Gaseous fuel supply unit 32 ... Filter 33 ... Oxidant supply unit 34 ... Oxidant supply amount adjustment unit 34B ... Fuel supply amount adjustment unit 35, 35B: Channel opening degree adjustment unit 36: Condensing unit 37 ... Ring Tank 38,36B ... controller F1~F8, F1B, F3B, F4B ... piping G1 to G3 ... pump 40 ... external fuel tank 41 ... external load

Claims (10)

A fuel cell;
An oxidant supply unit for supplying an oxidant to the cathode of the fuel cell;
An oxidant supply amount adjusting unit that is provided in the oxidant supply unit and adjusts the supply amount of the oxidant;
An oxidant discharge passage part connected to the cathode electrode and discharging at least the oxidant;
A channel opening degree adjusting unit that is provided in the oxidant discharging channel unit and adjusts the channel opening degree of the oxidant discharging channel unit;
A control unit connected to the cathode electrode and controlling the oxidant supply amount adjustment unit and the flow path opening degree adjustment unit;
A fuel cell system comprising:
The controller determines whether or not a flooding phenomenon has occurred at the cathode electrode during normal operation of the fuel cell. If it is determined that a flooding phenomenon has occurred, the supply amount of the oxidant increases. In this way, the oxidant supply flow rate adjusting unit is controlled to increase the oxidant supply amount, and the oxidant discharge flow path is maintained while maintaining the same amount as the oxidant supply amount during the normal operation. The flow rate opening degree decrease control for controlling the flow rate opening degree adjustment unit is performed simultaneously with the oxidant supply amount increase control so that the flow rate degree of the flow path of the unit decreases, and the operation state of the fuel cell system is changed from the normal operation. A fuel cell system that shifts to a flooding phenomenon reduction operation that reduces the flooding phenomenon. The fuel cell system according to claim 1,
After a predetermined time has elapsed since the oxidant supply amount increase control and the flow path opening degree decrease control have been performed, the control unit is configured to supply the oxidant supply amount and the flow degree of the oxidant discharge flow path unit. The oxidant supply amount reduction control for controlling the oxidant supply amount adjustment unit so that the supply amount of the oxidant is reduced until the oxidant supply amount decreases to the same level as in the normal operation, and the flow path of the oxidant discharge flow path unit The flow rate opening degree increasing control is performed to control the flow rate opening degree adjusting unit so that the opening degree increases, and the operation state of the fuel cell system is shifted from the flooding phenomenon reducing operation to the normal operation. Fuel cell system. The fuel cell system according to claim 2, wherein
The control unit simultaneously performs the oxidant supply amount decrease control and the flow path opening degree increase control while maintaining the same amount as the oxidant supply amount during the flooding phenomenon reduction operation. Fuel cell system. The fuel cell system according to claim 1,
After a predetermined time has elapsed since the oxidant supply amount increase control and the flow path opening degree decrease control have been performed, the control unit controls the oxidant supply amount adjustment unit so that the supply of the oxidant is stopped. A predetermined time has elapsed after performing the oxidant supply stop control and the flow rate opening degree increasing control for controlling the flow rate opening degree adjusting unit so that the flow rate opening degree of the oxidant discharge flow path portion increases. In this case, the oxidant supply amount is increased so that the oxidant supply amount is increased until the supply amount of the oxidant and the degree of openness of the oxidant discharge flow path portion are the same as those during the normal operation. An oxidant supply amount increase control for controlling the adjusting unit and a channel open degree decreasing control for controlling the channel open degree adjusting unit so as to reduce the channel open degree of the oxidant discharge channel unit are performed, and a fuel cell The operating state of the system is changed from the flooding phenomenon reducing operation Fuel cell system, characterized in that shifting the normally operating. The fuel cell system according to claim 4, wherein
The fuel cell system, wherein the controller performs the oxidant supply stop control and the flow path opening degree increase control at the same time, or performs the oxidant supply stop control after the flow path open degree increase control. The fuel cell system according to claim 4 or 5, wherein
The control unit simultaneously performs the oxidant supply amount increase control and the flow path opening degree decrease control while maintaining the same amount as the oxidant supply amount during the flooding phenomenon reduction operation. Fuel cell system. It is a fuel cell system as described in any one of Claims 4-6,
The fuel cell system, wherein the control unit controls the channel opening degree adjusting unit until the channel opening degree of the oxidant discharge channel unit becomes maximum in the channel opening degree increase control. A fuel cell;
A gaseous fuel supply unit for supplying gaseous fuel to the anode electrode of the fuel cell;
A fuel supply amount adjustment unit that is provided in the gaseous fuel supply unit and adjusts the supply amount of the gaseous fuel;
A fuel discharge channel connected to the anode electrode and discharging at least the gaseous fuel;
A flow path opening degree adjusting section provided in the fuel discharge flow path section for adjusting a flow opening degree of the fuel discharge flow path section;
A control unit connected to the anode electrode and controlling the fuel supply amount adjustment unit and the flow path opening degree adjustment unit;
A fuel cell system comprising:
The control unit determines whether or not a flooding phenomenon has occurred at the anode electrode during normal operation of the fuel cell, and when it is determined that a flooding phenomenon has occurred, the gaseous fuel during the normal operation is determined. The fuel supply amount increase control for controlling the fuel supply amount adjustment unit so that the supply amount of the gaseous fuel is increased while maintaining the same amount as the supply amount of A fuel cell system characterized by simultaneously performing flow path openness reduction control for controlling the flow path openness adjusting unit so as to decrease, and shifting the operating state of the fuel cell system from the normal operation to the flooding phenomenon reducing operation. . The fuel cell system according to claim 8, wherein
After a predetermined time has elapsed since the fuel supply amount increase control and the flow path opening degree decrease control have been performed, the control unit determines that the supply amount of the gaseous fuel and the flow path open degree of the fuel discharge flow path portion are The fuel supply amount decrease control for controlling the fuel supply amount adjustment unit and the degree of openness of the fuel discharge passage unit increase so that the supply amount of the gaseous fuel decreases until the same level as during normal operation. In this way, the fuel cell system is characterized in that the flow rate opening degree increasing control for controlling the flow rate opening degree adjusting unit is performed to shift the operation state of the fuel cell system from the flooding phenomenon reducing operation to the normal operation. The fuel cell system according to claim 9, wherein
The control unit simultaneously performs the fuel supply amount decrease control and the flow path opening degree increase control while maintaining the same amount as the supply amount of the oxidant during the flooding phenomenon reduction operation. Battery system.

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