CN111801825B - Fuel cell system and control method of fuel cell system - Google Patents
Fuel cell system and control method of fuel cell system Download PDFInfo
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- CN111801825B CN111801825B CN201880078754.5A CN201880078754A CN111801825B CN 111801825 B CN111801825 B CN 111801825B CN 201880078754 A CN201880078754 A CN 201880078754A CN 111801825 B CN111801825 B CN 111801825B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
- H01M8/04097—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with recycling of the reactants
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
- H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
- H01M8/04156—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying with product water removal
- H01M8/04164—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying with product water removal by condensers, gas-liquid separators or filters
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
- H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
- H01M8/0438—Pressure; Ambient pressure; Flow
- H01M8/04388—Pressure; Ambient pressure; Flow of anode reactants at the inlet or inside the fuel cell
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
- H01M8/0438—Pressure; Ambient pressure; Flow
- H01M8/04395—Pressure; Ambient pressure; Flow of cathode reactants at the inlet or inside the fuel cell
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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Abstract
The fuel cell system of the present embodiment includes: a fuel cell having a fuel electrode channel and an oxidant channel, and generating power using a hydrogen-containing gas supplied to the fuel electrode and an oxygen-containing gas supplied to the oxidant electrode; a blower unit provided in a recirculation gas flow path for recirculating anode off-gas, for sucking anode off-gas from a downstream side of the fuel electrode flow path and discharging the anode off-gas to a downstream side of the recirculation gas flow path; a discharge valve section for opening and closing a discharge flow path for discharging a part of the anode off-gas from a branch section provided between the gas blower and the joining section in the recycle gas flow path; a pressure loss element unit disposed between the branch portion of the discharge flow path and the discharge valve unit, the pressure loss being greater than the pressure loss of the fuel electrode flow path in the fuel cell; and a control device for controlling the pressure of the outlet of the blowing section between the blowing section and the merging section of the recirculation gas flow path to be higher than the pressure in the hydrogen gas supply flow path.
Description
Technical Field
Embodiments of the present invention relate to a fuel cell system and a control method of the fuel cell system.
Background
A fuel cell system generally generates electricity using a hydrogen-containing gas supplied to a fuel electrode in a fuel cell and an oxygen-containing gas supplied to an oxidant electrode in the fuel cell. The anode off-gas discharged from the fuel electrode during power generation contains unreacted hydrogen. Therefore, the anode off-gas is sometimes resupplied to the fuel cell for power generation.
When the anode off-gas is circulated, the concentration of impurities and the like contained in the anode off-gas increases with the passage of time, and the voltage of the fuel cell decreases. Therefore, a discharge flow path is connected to a recirculation gas flow path for circulating the anode off-gas, and a discharge valve of the discharge flow path is opened as necessary to discharge the produced water and impurities together with a part of the anode off-gas. This reduces the impurity concentration and the like in the anode off-gas reused for power generation.
However, in order not to discharge the hydrogen-containing gas supplied from the outside when the anode off-gas is discharged, a valve for preventing backflow is generally provided in the recirculation gas flow path, and a pressure loss occurs in the recirculation gas flow path. Therefore, the auxiliary power of the gas blower provided in the recirculation gas flow path increases, and the power generation efficiency of the entire fuel cell system may decrease.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2005-93232
Disclosure of Invention
Technical problem to be solved by the invention
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel cell system and a method of controlling the fuel cell system, which can suppress a pressure loss in a recirculation gas flow path.
Means for solving the problems
The fuel cell system of the present embodiment includes: a fuel cell having a fuel electrode channel for supplying a hydrogen-containing gas supplied from a hydrogen gas supply channel to a fuel electrode and an oxidant channel for supplying an oxygen-containing gas to an oxidant electrode, and generating power using the hydrogen-containing gas supplied to the fuel electrode and the oxygen-containing gas supplied to the oxidant electrode; a blower unit provided in a recirculation gas flow path for returning anode off-gas discharged from the fuel electrode flow path through a junction with the hydrogen gas supply flow path, the blower unit sucking the anode off-gas from a downstream side of the fuel electrode flow path and discharging the anode off-gas to a downstream side of the recirculation gas flow path; a discharge valve unit that opens and closes a discharge flow path that discharges a part of the anode off-gas from a branch portion provided between the blowing unit and the merging unit in the recirculation gas flow path; a pressure loss element unit that is arranged between the branch portion of the discharge flow path and the discharge valve unit, and has a pressure loss greater than a pressure loss of the fuel electrode flow path in the fuel cell; and a control device for controlling the pressure at the outlet of the blowing section between the blowing section and the merging section of the recirculation gas flow path to be higher than the pressure in the hydrogen gas supply flow path.
A method for controlling a fuel cell system according to the present embodiment includes: a fuel cell having a fuel electrode channel for supplying a hydrogen-containing gas supplied from a hydrogen gas supply channel to a fuel electrode and an oxidant channel for supplying an oxygen-containing gas to an oxidant electrode, and generating power using the hydrogen-containing gas supplied to the fuel electrode and the oxygen-containing gas supplied to the oxidant electrode; a blower unit provided in a recirculation gas flow path for returning anode off-gas discharged from the fuel electrode flow path through a junction with the hydrogen gas supply flow path, the blower unit sucking the anode off-gas from a downstream side of the fuel electrode flow path and discharging the anode off-gas to a downstream side of the recirculation gas flow path; a discharge valve unit that opens and closes a discharge flow path that discharges a part of the anode off-gas from a branch portion provided between the blowing unit and the merging unit in the recirculation gas flow path; and a pressure loss element unit disposed between the branch unit and the discharge valve unit of the discharge flow path, the pressure loss being greater than the pressure loss of the fuel electrode flow path in the fuel cell, the method for controlling the fuel cell system including: the blowing section is controlled so that the pressure at the outlet of the blowing section between the blowing section and the merging section of the recycle gas flow path is higher than the pressure in the hydrogen gas supply flow path.
Drawings
Fig. 1 is a schematic configuration diagram of the entire fuel cell system.
Fig. 2 is a diagram schematically showing an example of the structure of the fuel cell.
Fig. 3 is a diagram showing a relationship between pressures in the pipes.
Fig. 4 is a schematic configuration diagram of the entire fuel cell system of the second embodiment.
Fig. 5 is a flowchart showing an example of control of the fuel cell system according to the third embodiment.
Fig. 6 is a schematic configuration diagram of the entire fuel cell system of the fourth embodiment.
Fig. 7 is a flowchart showing an example of control of the fuel cell system according to the fourth embodiment.
Fig. 8 is a structural diagram of a discharge flow path in the fifth embodiment.
Fig. 9 is a structural diagram of a discharge flow path of the sixth embodiment.
Fig. 10 is a side view of an eccentric reducer.
Fig. 11 is a configuration diagram of the entire fuel cell system of the seventh embodiment.
Fig. 12 is a side view of an eccentric reducer using an eccentric orifice (eccentric installation).
Detailed Description
Hereinafter, a fuel cell system and a control method of the fuel cell system according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are examples of the embodiments of the present invention, and the present invention is not limited to these embodiments. In the drawings referred to in the present embodiment, the same or similar reference numerals are used for the same or similar parts and redundant description thereof may be omitted. For convenience of explanation, the dimensional ratios in the drawings may be different from the actual ratios or may be partially omitted from the drawings.
(first embodiment)
First, the overall configuration of the fuel cell system 1 will be described with reference to fig. 1. Fig. 1 is a schematic configuration diagram of the entire fuel cell system 1. As shown in fig. 1, the fuel cell system 1 is a system capable of reusing anode off-gas discharged from a fuel electrode of a fuel cell during power generation, and includes a hydrogen gas supply passage 2, an oxygen gas supply passage 4, a recirculation gas passage 6, a merging portion 8, a discharge passage 10, a branching portion 12, a first cooling water passage 14, a second cooling water passage 16, a load 18, a fuel cell 100, a hydrogen gas supply device 102, an oxidizing agent supply device 104, an air blowing portion 106, a discharge valve portion 108, a pressure loss element portion 110, a water tank 112, a water pump 114, and a control device 116. Fig. 1 shows a Z direction parallel to the up-down direction of the fuel cell 100 and X and Y directions perpendicular to the Z direction and parallel to each other. When the fuel cell 100 of the present embodiment is disposed on a horizontal plane, the Z direction is parallel to the direction of gravity.
The hydrogen gas supply flow path 2 is a flow path connected between the inlet of the fuel electrode flow path 100a of the fuel cell 100 and the hydrogen gas supply device 102, and supplies the hydrogen-containing gas to the fuel electrode flow path 100a in the fuel cell 100. The oxygen gas supply channel 4 is a channel connected between the inlet of the oxygen gas supply channel 4 and the oxidant electrode channel 100b in the fuel cell 100, and supplies the oxygen-containing gas to the oxidant electrode channel 100b of the fuel cell 100.
The recycle gas flow path 6 is a flow path connected between the outlet portion of the fuel electrode flow path 100a and the junction 8 of the hydrogen gas supply flow path 2 in the fuel cell 100. The recirculation gas flow path 6 returns the anode off-gas discharged from the fuel electrode flow path 100a through the joining portion 8 of the hydrogen supply flow path 2.
The discharge flow path 10 is a flow path branched from the branching section 12 provided between the blowing section 106 and the merging section 8 in the recirculation gas flow path 6, and discharges a part of the anode off-gas. The first cooling water channel 14 is a channel connected between the water tank 112 and the inlet of the water channel in the fuel cell 100, and supplies cooling water to the water channel in the fuel cell 100. The second cooling water flow path 16 is a flow path connected between the water tank 112 and an outlet portion of the water flow path in the fuel cell 100, and supplies the cooling water discharged from the water flow path in the fuel cell 100 to the water tank 112.
The load 18 consumes the electric power generated by the fuel cell 100. The fuel cell system 1 corresponds to an electric motor or the like when mounted on a vehicle, corresponds to a PC, lighting, or the like of a factory when connected to an electric system of the factory, and corresponds to lighting, home appliances, or the like when connected to an electric system of a general house.
The fuel cell 100 includes a fuel electrode passage 100a for supplying a hydrogen-containing gas to a fuel electrode and an oxygen-containing gas passage 100b for supplying an oxygen-containing gas to an oxygen-containing electrode therein, and generates electric power using the hydrogen-containing gas supplied to the fuel electrode and the oxygen-containing gas supplied to the oxygen-containing electrode. Here, the anode off-gas is a gas discharged from the fuel electrode flow path 100a during power generation of the fuel cell 100, and includes unreacted hydrogen. The detailed configuration of the fuel cell 100 will be described later.
The hydrogen gas supply device 102 is, for example, a compressor that supplies a hydrogen-containing gas generated by reforming a hydrocarbon fuel by a reformer to the fuel electrode flow path 100a. The hydrogen gas supply device 102 supplies a hydrogen-containing gas from the upstream side of the fuel electrode flow path 100a of the fuel cell 100 through the hydrogen gas supply flow path 2. Further, a hydrogen cylinder or the like may be used as the hydrogen gas supply device 102.
The oxidizing agent supply device 104 is, for example, a blower, and is provided upstream of the oxygen supply flow path 4. The oxygen-containing gas is supplied from the oxygen-containing gas supply device 104 to the oxygen-containing gas flow path 100b of the fuel cell 100 through the oxygen supply flow path 4.
The blower 106 is, for example, a diaphragm pump, roots pump, or scroll pump, and is provided in the recirculation gas flow path 6 upstream of the junction 8 of the hydrogen gas supply flow path 2. The air blowing unit 106 sucks the anode off-gas from the downstream side of the fuel electrode and discharges the anode off-gas to the downstream side of the air blowing unit 106 of the recirculation gas flow path 6.
The discharge valve 108 opens and closes the discharge flow path 10 for discharging a part of the anode off-gas. The pressure loss element section 110 is a pressure loss element having a larger pressure loss than the fuel electrode flow path 100a in the fuel cell 100, and is disposed between the branch section 12 of the discharge flow path 10 and the discharge valve section 108.
The water tank 112 stores water supplied to the water flow path in the fuel cell 100, and supplies cooling water to the water flow path in the fuel cell 100 via the first cooling water flow path 14. The water pump 114 is provided in the second cooling water flow path 16, and sucks up water from the water flow path in the fuel cell 100 by negative pressure to return the water to the water tank 112.
The control device 116 controls the entire fuel cell system 1. The control device 116 is, for example, a microcomputer including a CPU (Central Processing Unit), a storage device, an input/output device, and the like. The control device 116 reads signals from various sensors, not shown, provided in the fuel cell system 1. Further, based on the read various signals and control logic (program) stored in advance therein, commands are transmitted to the respective components of the fuel cell system 1, such as the hydrogen gas supply device 102, the oxidizing agent supply device 104, the air blowing unit 106, and the discharge valve unit 108. In this way, the controller 116 comprehensively manages and controls all operations necessary for the operation/stop of the fuel cell system 1.
The detailed structure of the fuel cell 100 will be described with reference to fig. 2. Fig. 2 is a diagram schematically showing an example of the configuration of the fuel cell 100. As shown in fig. 2, the fuel cell 100 is configured by stacking a plurality of fuel cells 100 c. The fuel cell 100c includes a membrane electrode assembly 100d, a fuel electrode separator 100e, and an oxidant electrode separator 100f.
The membrane electrode assembly 100d includes a solid polymer electrolyte membrane, a fuel electrode disposed on one surface of the solid polymer electrolyte membrane, and an oxidant electrode disposed on the surface of the solid polymer electrolyte membrane opposite to the fuel electrode. A fuel electrode flow path 100a is formed in the fuel electrode separator 100 e. An oxidant electrode flow path 100b is formed in the oxidant electrode separator 100f. A water flow path 20 for humidifying the fuel electrode separator 100e and the oxidant electrode separator 100f is formed between the fuel cells 100 c. The water flow path 20 is formed independently of the fuel electrode membrane 100e or the oxidant electrode membrane 100f by a watertight plate formed with a groove. The water flow channel 20 is formed on the surface of the fuel electrode separator 100e opposite to the surface on which the fuel electrode flow channel 100a is formed and on the surface of the oxidant electrode separator 100f opposite to the surface on which the oxidant electrode flow channel 100b is formed. In the present embodiment, the fuel electrode separator 100e and the oxidant electrode separator 100f are independent from each other, but may be formed integrally.
The plurality of fuel cell cells 100c generate electricity through the reaction shown in chemical formula 1. The hydrogen-containing gas flows through the fuel electrode flow path 100a on the fuel electrode side, and causes a fuel electrode reaction. The oxygen-containing gas flows through the oxidant electrode flow path 100b on the oxidant electrode side, and causes an oxidant electrode reaction. The fuel cell 100 takes out electric energy from the electrodes by using these electrochemical reactions.
(chemical formula 1)
Fuel pole reaction: h 2 →2H + +2e-
And (3) oxidizing agent polar reaction: 2H + +2e- + (1/2) O 2 →H 2 O
One of the performances of the fuel cell 100 is represented by current-voltage characteristics. The actual voltage of the fuel cell 100 when a predetermined current flows is lower than the theoretical value. One of the causes of this voltage drop is a diffusion overvoltage due to the supply of a reaction gas, the influence of water produced during the cell reaction, and the like. When water is generated by the electrochemical reaction between hydrogen and oxygen in the fuel cell 100c and the water fills pores of the gas diffusion layer of the electrode component, the diffusion of the reaction gas is reduced. This increases the diffusion overvoltage.
Therefore, the fuel electrode separator 100e and the oxidant electrode separator 100f of the present embodiment are formed of porous separators. For example, the fuel electrode separator 100e and the oxidant electrode separator 100f are formed of porous carbon. These separators can contain water required for humidification of the electrolyte membrane inside the porous body. Further, by setting the water flow path 20 to a pressure lower than the atmospheric pressure, the generated water by the electrode reaction can be sucked up from the diaphragm and absorbed into the water flow path 20, and overflow on the gas downstream side can be prevented. This can suppress an increase in the diffusion overvoltage. Alternatively, the porous separator may be made of a metal oxide.
In addition, the fuel cell 100 of the present embodiment may use a dense separator made of stainless steel, carbon, or the like. If a dense diaphragm is used, an antifreeze such as ethylene glycol or propylene glycol can be passed through the water flow path 20 and the water tank 112. In this case, the water passage method may be positive pressure.
The pipes such as the hydrogen gas supply passage 2, the recycle gas passage 6, and the discharge passage 10 through which the hydrogen-containing gas flows are made of stainless steel such as SUS304 or SUS 316L. The pipes are connected to each other and to the equipment by flanges, screw joints using sealing tape, or Swagelok (Swagelok) joints.
The material of the pipe is not ferritic stainless steel which is likely to cause hydrogen embrittlement, but austenitic stainless steel. In general, SUS316L, which is an austenite system, is required to be used for high-pressure hydrogen piping. Low-pressure hydrogen piping is not required to be made of any material, and therefore inexpensive austenitic SUS304 is used.
When a thin pipe is connected to the center of the thick pipe in the vertical direction, condensed water stays in the thick pipe before the hole of the thin pipe is opened, and the flow of condensed water becomes irregular, resulting in irregular supply of hydrogen. In addition, when condensed water is retained, the risk of rust in the pipe increases. Therefore, in the present embodiment, when a relatively thin pipe is connected to a relatively thick pipe, an eccentric reducing pipe is used. This makes it possible to flow the condensed water to the downstream fine piping without causing the condensed water generated upstream to stagnate.
Further, the energy required for ignition of hydrogen is very small, and there is a risk of ignition even by static electricity or the like. Therefore, all the pipes through which hydrogen flows are connected to the ground. That is, since the seal, the seal tape, and the like of the flange of the seal at the connection portion are not electrically conductive, wiring is provided between the connection portion and the piping or the equipment, and all the piping or the equipment through which hydrogen flows are connected to the ground.
Next, the operation of the first embodiment will be described. First, the flow of the oxygen-containing gas is explained. The oxygen-containing gas is supplied from the oxygen-containing gas supply device 104 to the oxygen-containing gas electrode flow path 100b of the fuel cell 100 through the oxygen-containing gas supply flow path 4 under the control of the control device 116. The oxygen-containing gas flowing into the oxidant electrode flow path 100b is supplied to the oxidant electrode of each fuel cell 100 c. A part of the oxygen-containing gas reaching the oxidant electrode receives the protons and electrons released from the fuel electrode as shown in chemical formula 1, and generates water.
Next, the flow of the hydrogen-containing gas will be described. The hydrogen gas supply device 102 supplies the hydrogen-containing gas to the fuel electrode flow path 100a of the fuel cell 100 through the hydrogen gas supply flow path 2 under the control of the control device 116. The hydrogen-containing gas flowing into the hydrogen gas supply passage 2 is supplied to the fuel electrode of each fuel cell 100 c. A part of the hydrogen-containing gas reaching the fuel electrode generates protons and electrons as shown in the above formula 1. The excess hydrogen-containing gas that is not used for power generation is discharged as anode off-gas from the outlet portion of the fuel electrode flow path 100a of the fuel cell 100 to the recirculation gas flow path 6. The recirculation gas flow path 6 returns the anode off-gas discharged from the fuel electrode flow path 100a through the joining portion 8 of the hydrogen supply flow path 2. At this time, the blower 106 sucks the anode off-gas from the downstream side of the fuel electrode and discharges the anode off-gas to the downstream side of the blower 106 of the recirculation gas flow path 6 under the control of the controller 116.
Next, the flow of a part of the anode off-gas discharged from the discharge flow path 10 will be described. The discharge valve portion 108 is opened by the control of the control device 116. Thereby, a part of the anode off-gas is discharged from the discharge valve portion 108.
Fig. 3 is a diagram showing the relationship between the pressure in the hydrogen gas supply passage 2 and the pressure at the outlet of the fuel electrode passage 100a in the fuel cell 100, that is, the pressure on the upstream side of the blowing part 106 of the recirculation gas passage 6 and the pressure at the outlet of the blowing part 106 of the recirculation gas passage 6. As shown in fig. 3, the controller 116 controls the pressure at the outlet of the blowing section 106 between the blowing section and the merging section of the circulating gas flow path to be higher than the pressure in the hydrogen gas supply flow path 2. The pressure loss of the pressure loss element section 110 of the discharge flow path 10 is configured to be greater than the pressure loss of the fuel electrode flow path 100a in the fuel cell 100. Since there is a pressure loss in the fuel pole flow path 100a, the discharge port of the upstream blowing section 106 is larger in pressure than the outlet portion of the fuel pole flow path 100a of the downstream fuel cell 100. The pressure loss is an energy loss per unit time unit flow path when the fluid passes through the pressure loss element unit 110 or the like.
That is, the pressure loss of the pressure loss element section 110 of the discharge flow path 10 is configured to be larger than the pressure loss of the fuel electrode flow path 100a in the fuel cell 100, and when the control device 116 controls the pressure at the outlet of the air blowing section 106 between the air blowing section 106 and the junction 8 of the recirculation gas flow path 6 to be higher than the pressure in the hydrogen gas supply flow path 2, the pressure at the outlet of the air blowing section 106 between the air blowing section 106 and the junction 8 of the recirculation gas flow path 6, the pressure in the hydrogen gas supply flow path 2, and the pressure in the recirculation gas flow path 6 at the outlet of the fuel electrode flow path 100a in the fuel cell 100 are sequentially increased. As a result, even when the discharge valve portion 108 is opened by the control of the control device 116 and a part of the anode off-gas is discharged from the discharge valve portion 108, the hydrogen-containing gas in the hydrogen gas supply channel 2 does not flow back into the recycle gas channel 6. Therefore, the check valve is not required to be provided in the recirculation gas flow path 6, and the output of the blower 106 can be suppressed.
As shown in fig. 3, the pressure difference between the hydrogen gas supply passage 2 and the discharge port of the blowing unit 106 is about 6 kpa, and the suction capacity of the blowing unit 106 may be relatively low. The pressure difference between the discharge port of the blower 106 between when the anode off-gas is discharged and when the discharge of the anode off-gas is stopped is less than 8 kpa. Similarly, the pressure difference between the inside of the hydrogen supply passage 2 at the time of anode off-gas discharge and at the time of stopping the anode off-gas discharge is less than 0.5 kpa, and the pressure difference at the outlet of the fuel electrode passage 100a of the fuel cell 100 is less than 0.5 kpa.
Next, the flow of the cooling water supplied from the water tank 112 to the water flow path 20 in the fuel cell 100 will be described. The cooling water supplied from the water tank 112 to the water flow path 20 in the fuel cell 100 is contained in the porous separators 100e and 100f of the fuel electrode separator 100e and the oxidant electrode separator 100f. Thus, water necessary for humidification of the membrane electrode assembly 100d is supplied from the fuel electrode membrane 100e and the oxidant electrode membrane 100f.
The cooling water in the water flow path 20 is sucked up by the water pump 114 through the second cooling water flow path 16 and supplied to the tank 112. At this time, if the water pump 114 sucks up water from the water flow path 20 of the fuel cell 100 by the negative pressure and the water flow path 20 is brought to a pressure lower than the atmospheric pressure, the produced water generated by the electrode reaction is sucked up from the fuel electrode membrane 100e and the oxidant electrode membrane 100f and is absorbed by the water flow path 20. This suppresses the occurrence of the downstream side of the fuel electrode flow path 100a and the oxidant electrode flow path 100b.
As described above, according to the present embodiment, the pressure loss of the pressure loss element section 110 of the discharge passage 10 is configured to be larger than the pressure loss of the fuel electrode passage 100a in the fuel cell 100, and the control device 116 controls the pressure at the outlet of the air blowing section 106 between the air blowing section 106 and the junction 8 of the recycle gas passage 6 to be higher than the pressure in the hydrogen gas supply passage 2. Thus, when the anode off-gas is discharged from the discharge passage 10, the pressure of the recirculation gas passage 6 from the discharge port of the blowing unit 106 to the junction 8 of the hydrogen gas supply passage 2 is higher than that of the hydrogen gas supply passage 2. Therefore, even if the recirculation gas flow path 6 is not provided with a check valve, the flow of the hydrogen-containing gas supplied from the hydrogen gas supply device 102 into the discharge flow path 10 can be suppressed, and the energy utilization efficiency of the entire fuel cell system 1 can be improved.
Further, when the oxidant electrode separator 100f and the fuel electrode separator 100e are formed of porous separators, water necessary for humidifying the electrolyte membrane is supplied from the fuel electrode separator 100e and the oxidant electrode separator 100f. Further, by setting the water flow passage 20 to a pressure lower than the atmospheric pressure, the excess liquid water located in the membrane electrode assembly 100d is sucked up from the separators 100e and 100f and absorbed into the water flow passage 20, thereby suppressing the flooding phenomenon. By suppressing this flooding, it is possible to suppress an increase in diffusion polarization, and to suppress cell deterioration due to an increase in cell voltage or hydrogen deficiency in the fuel electrode.
(modification of the first embodiment)
The fuel cell system 1 according to the modification of the first embodiment is different from the fuel cell system 1 according to the first embodiment in that the control device 116 further has a function of changing the output of the blower 106 in proportion to the current value supplied from the fuel cell 100 to the load 18. The overall configuration of the fuel cell system 1 is the same as that of the fuel cell system 1 of the first embodiment, and therefore, the description thereof is omitted. Hereinafter, differences from the fuel cell system 1 of the first embodiment will be described.
The amount of hydrogen used by the fuel cell 100 in power generation is proportional to the current value, and therefore the amount of anode off-gas discharged is proportional to the current value. Therefore, the control device 116 of the present modification controls the air blowing amount of the air blowing unit 106 based on the value of the current flowing through the load 18. The controller 116 changes the output of the blower 106 in proportion to the value of the current supplied from the fuel cell 100 to the load 18. For example, if the blower 106 is a recirculation gas blower, the controller 116 increases the rotation speed of the recirculation gas blower when the current value supplied from the fuel cell 100 to the load 18 increases, and decreases the rotation speed of the recirculation gas blower when the current value decreases. The general blower 106 is controlled by feedback control based on a flow meter for supplying air to the fuel cell 100. Therefore, the response of the blower 106 is delayed, and the hydrogen utilization rate may be lowered.
As described above, according to the present modification, the control device 116 controls the air blowing amount of the air blowing unit 106 based on the value of the current flowing through the load 18. This makes the response faster, and therefore the flow rate of hydrogen supplied to the fuel cell 100 can be made closer to the target value. This can suppress the reduction in power generation efficiency due to the reduction in hydrogen utilization rate and the deterioration of the monomer due to hydrogen deficiency. In addition, since it is not necessary to provide a flow meter required for general feedback control, the cost can be reduced.
(second embodiment)
The fuel cell system 1 of the present embodiment differs from the fuel cell system 1 of the first embodiment in that a condensation heat exchanger 118 and a drain trap (drain trap) 120 are provided upstream of the blower 106 of the recirculated gas flow path 6. Hereinafter, differences from the fuel cell system 1 of the first embodiment will be described.
Fig. 4 is a schematic configuration diagram of the entire fuel cell system 1 of the second embodiment. As shown in fig. 4, the fuel cell system 1 of the second embodiment further includes a condensation heat exchanger 118 and a drain valve 120. The condensing heat exchanger 118 and the drain valve 120 are disposed upstream of the blower portion 106 of the recirculated gas flow path 6.
The condensation heat exchanger 118 exchanges heat between the supplied tap water and the anode off-gas flowing in from the recirculated gas flow path 6. Thereby, the anode off-gas is cooled and moisture is condensed. Further, the tap water discharged from the condensation heat exchanger 118 can also be supplied as hot water. The antifreeze may be supplied and circulated instead of the tap water, and the antifreeze and the tap water may be heat-recovered through different heat exchangers.
When air flows back into the recirculation gas flow path 6, hydrogen and oxygen are mixed, and there is a risk of ignition. Therefore, it is necessary to prevent the reverse flow of air from the drain water passage 22 to the recirculated gas passage 6. Further, if a check valve is provided in the drain water passage 22 in order to prevent the air from flowing backward from the drain water passage 22 to the recirculation gas passage 6, a pump is required to discharge the condensed water because the check valve causes a pressure loss. Therefore, in the fuel cell system 1 of the present embodiment, the drain valve 120 is provided in the drain passage 22.
The drain valve 120 stores the moisture condensed by the cooling of the anode off-gas in the drain water flow path 22. More specifically, the drain valve 120 is provided in the vertical direction with respect to the liquid surface of the tank 112, and the drain flow path 22 including the tank 112 is discharged from the outside of the system in the vertical direction after being directed downward in the vertical direction from the drain valve 120. The uppermost portion of the liquid surface of the drain flow path 22 is disposed in the vertical direction of the drain valve 120. This can suppress accumulation of water in the drain/drain passage 22, and can prevent the outside air from flowing back to the recirculation gas passage 6 through the drain/drain passage 22. Thus, even if the check valve is not provided, the reverse flow of air and moisture from the outside of the system can be prevented.
The blower 106 and the condensation heat exchanger 118 are disposed at positions in the vertical direction with respect to the trap 120. In this way, the condensing heat exchanger 118 is disposed upstream of the trap 120 and closer to the fuel cell 100 than the trap 120.
Next, a flow of the anode off-gas cooling process by the condensing heat exchanger 118 will be described. The anode off-gas supplied from the recirculation flow path to the condensing heat exchanger 118 is cooled by heat exchange with the tap water. Thereby, the moisture in the anode off-gas is condensed and discharged through the drain valve 120. This can prevent moisture contained in the anode off-gas from entering the blower 106 and the pressure loss element 110.
The drain flow path 22 of the drain valve 120 drains vertically after facing vertically downward, and therefore the drain flow path 22 of the drain valve 120 is filled with water. This can suppress the backflow of the outside air into the recirculation gas flow path 6 through the drain water flow path 22.
The uppermost portion of the liquid surface of the drain/drain passage 22 is disposed vertically below the drain valve 120. This suppresses the reverse flow of water in the hydrophobic discharge passage 22 to the hydrophobic valve 120.
As described above, according to the present embodiment, moisture in the anode off-gas is discharged by the condensing heat exchanger 118, and therefore, entry of moisture into the blower unit 106 and the pressure loss element unit 110 can be suppressed. This reduces the possibility of the air blowing unit 106 failing, and reduces the possibility of the pressure loss element unit 110 being sealed with moisture.
Further, the condensation heat exchanger 118 is disposed in the vertical direction of the trap 120 at a position upstream of the trap 120 and close to the fuel cell 100. Therefore, the condensation heat exchanger 118 can recover waste heat from the anode off-gas with little heat loss, and can efficiently recover the condensed water obtained by condensing the water vapor of the anode off-gas to the drain valve 120.
Further, since the uppermost portion of the liquid surface of the hydrophobic discharge passage 22 is disposed vertically below the hydrophobic valve 120, the water in the hydrophobic discharge passage 22 can be discharged to the outside of the system without flowing back to the hydrophobic valve 120. Therefore, even if no check valve is provided, the backflow of water and air from the drain/drain passage 22 can be prevented.
(third embodiment)
The fuel cell system 1 of the present embodiment is different from the fuel cell system 1 of the first embodiment in that the control device 116 further has a function of alternately repeating a closed state in which the discharge valve portion 108 is closed for a certain period of time and an open state in which the discharge valve portion 108 is opened for a certain period of time. The overall configuration of the fuel cell system 1 is the same as that of the fuel cell system 1 of the first embodiment, and therefore, the description thereof is omitted. The following description deals with differences from the fuel cell system 1 of the first embodiment.
The control means 116 (fig. 1) performs control of the discharge valve portion 108 based on a control table relating to the timing of discharge and shutdown of the anode off-gas. The control table is determined based on the results of the preliminary experiment. For example, the control table is determined based on a balance between a decrease in voltage due to an increase in diffusion polarization and an increase in voltage due to the discharge of anode off-gas when the fuel cell 100 is caused to generate power while keeping the anode off-gas not discharged.
More specifically, the control table determines the ratio of the time of discharge to the time of shutdown based on parameters such as the current value of the fuel cell 100, the number of cells with respect to the power generation output of the fuel cell 100, the air utilization rate of the fuel cell 100, and the like. For example, as the current value of the fuel cell 100 increases, the amount of generated water increases, and therefore the hydrogen concentration of the fuel electrode decreases, and the time until the cell voltage decreases becomes shorter, and therefore the proportion of the time determined as the discharge becomes larger.
Further, the lower the air utilization rate, the greater the air supply amount with respect to the current value, the higher the pressure of nitrogen in the oxidant electrode, and therefore, the larger the proportion of time to discharge. Further, when the pressure of nitrogen in the oxidizer electrode becomes high, the amount of nitrogen penetrating through the electrolyte membrane and entering the fuel electrode increases, and therefore the hydrogen concentration in the fuel electrode decreases. By increasing the proportion of the time of discharge, a decrease in the hydrogen concentration of the fuel electrode is suppressed.
Further, as the number of cells included in the fuel cell 100 is smaller, the stack voltage decreases and the current value with respect to the power generation output increases, so that the proportion of the time determined as the discharge increases. Further, when the current value with respect to the power generation output increases, the amount of generated water increases, so that the hydrogen concentration of the fuel electrode is likely to decrease, and the time until the cell voltage decreases becomes short. Therefore, by increasing the proportion of the discharge time, the time until the cell voltage decreases is suppressed to be short. The number of cells that the fuel cell 100 has is, for example, of the order of tens of cells in the fuel cell 100 having a capacity of 0.7 kilowatts, of the order of one hundred and tens of cells in the fuel cell 100 having a capacity of 3.5 kilowatts, and of the order of hundreds of cells in the fuel cell 100 having a capacity of 100 kilowatts.
Further, the higher the hydrogen utilization rate, the smaller the proportion of the hydrogen supply amount to the current value, and therefore the greater the proportion of time determined as discharge. If the ratio of the hydrogen supply amount to the current value is small, the hydrogen concentration is likely to decrease due to nitrogen or water entering from the oxidant electrode. Therefore, by increasing the proportion of the time for discharging, the proportion of the hydrogen supply amount to the current value is suppressed from decreasing.
Fig. 5 is a flowchart showing an example of control of the fuel cell system 1 according to the third embodiment. Here, the timing of the discharge and shutdown of the anode off-gas is determined based on the current value of the fuel cell 100, the number of cells with respect to the power generation output, and the air utilization rate of the fuel cell 100.
First, the control device 116 performs control to open the valve of the discharge valve portion 108 (step S100). Subsequently, the control device 116 determines whether or not the discharge time specified by the control block (Japanese: control テーブ) has elapsed (step S102). If the discharge time has not elapsed (no in step S102), the processing from step S100 onward is continued.
On the other hand, when the discharge time has elapsed (yes in step S102), the control device 116 performs control to close the valve of the discharge valve portion 108 (step S104). Next, the control device 116 determines whether or not the stop time determined by the control segment has elapsed (step S106). If the discharge time has not elapsed (no in step S106), the processing from step S104 onward is continued.
On the other hand, when the discharge time has elapsed (yes in step S106), the control device 116 determines whether or not to end the entire process (step S108). If the entire process is not ended (no in step S108), the processes from step S100 onward are repeated.
On the other hand, when the entire process is ended (yes in step S108), the control device 116 ends the entire process.
As described above, according to the present embodiment, the control device 116 discharges the anode off-gas for a predetermined time period, and stops the discharge of the anode off-gas for a predetermined time period. This can improve the hydrogen utilization rate and the power generation efficiency while suppressing a decrease in the voltage of the fuel cell 100. In addition, deterioration of the fuel cell 100 by hydrogen deficiency can be suppressed.
(fourth embodiment)
The fuel cell system 1 of the present embodiment is different from the fuel cell system 1 of the first embodiment in that the flow meter 122 is further provided upstream of the junction 8 between the recycle gas flow path 6 and the hydrogen gas supply flow path 2. Hereinafter, differences from the fuel cell system 1 of the first embodiment will be described.
Fig. 6 is a schematic configuration diagram of the entire fuel cell system 1 of the fourth embodiment. As shown in fig. 6, the fuel cell system 1 of the fourth embodiment further includes a flow meter 122, and the flow meter 122 is disposed upstream of the junction 8 between the recycle gas flow path 6 and the hydrogen gas supply flow path 2.
The flow meter 122 measures the amount of hydrogen supplied from the hydrogen gas supply device 102. The control device 116 stops the power generation of the fuel cell 100 when the hydrogen flow rate measured by the flow meter 122 deviates from the hydrogen flow rate corresponding to the power generation current of the fuel cell 100.
Similarly to the modification of the first embodiment, the controller 116 may change the output of the blower 106 in proportion to the value of the current supplied from the fuel cell 100 to the load 18, as in example 5. In this case, since the hydrogen flow rate is controlled by the blower rotation speed, the flow meter 122 can be used with a lower accuracy than usual. For example, a general flow meter for city gas may be used by being calibrated to the flow meter 122 for measuring the hydrogen flow rate. In the present embodiment, porous membranes are used for the fuel electrode membrane 100a and the oxidant electrode membrane 100b, and pure water is passed through the water flow path 14 and the water tank 112, but if dense membranes are used instead of porous membranes, it is also possible to pass anti-freezing liquid such as ethylene glycol or propylene glycol through the water flow path 14 and the water tank 112.
Fig. 7 is a flowchart showing an example of control of the fuel cell system 1 according to the fourth embodiment. As shown in fig. 7, the controller 116 acquires a measured value from the flowmeter 122 (step S200).
Next, the controller 116 determines whether or not the absolute value of the difference between the hydrogen flow rate corresponding to the generated current and the hydrogen flow rate measured by the flow meter 122 is greater than a predetermined threshold value (step S202). When the control device 116 is larger than the threshold value (yes in step S202), the control device 116 stops the power generation of the fuel cell 100.
On the other hand, if the threshold value is not more than the threshold value (no in step S202), the control device 116 repeats the processing from step S200. In this way, the controller 116 stops the power generation of the fuel cell 100 when the absolute value of the difference between the hydrogen flow rate corresponding to the generated current and the hydrogen flow rate measured by the flow meter 122 is greater than a predetermined threshold value. Since moisture discharged from the fuel cell 100 is supplied to the recirculation gas flow path 6, the moisture may enter the blower 106 and fail to operate normally. Thus, even if an abnormality occurs in the operation of blower 106, the power generation of fuel cell 100 can be stopped.
As described above, according to the present embodiment, when the hydrogen flow rate measured by the flow meter 122 deviates from the hydrogen flow rate corresponding to the power generation current of the fuel cell 100, the power generation of the fuel cell 100 is stopped. Accordingly, when the blower 106 does not operate normally, the power generation is stopped, and thus deterioration of the fuel cell 100 due to insufficient hydrogen can be suppressed.
(fifth embodiment)
Fig. 8 is a diagram showing a configuration of the discharge flow channel 10 according to the fifth embodiment. Fig. 8 illustrates the discharge flow path 10 and the pressure loss element unit 110 with parts removed. The fuel cell system 1 of the fifth embodiment differs from the fuel cell system 1 of the first embodiment in that a bypass flow path 121 is provided to connect the upstream and downstream of the pressure loss element unit 110. The center of the upstream opening of the bypass flow path 121 is located in the vicinity of the lowest portion in the vertical direction of the discharge flow path 10, and the pressure loss when the anode off-gas of the bypass flow path 121 is caused to flow is larger than the pressure loss when the anode off-gas is caused to flow through the pressure loss element unit 110, and the pressure loss when the condensed water of the bypass flow path 121 is caused to flow is smaller than the pressure loss when the anode off-gas is caused to flow through the pressure loss element unit 110.
The pressure loss element portion 110 is, for example, an orifice structure. In this case, in order to suppress water blocking to the pressure loss element portion, the pipe including the pressure loss element portion 110 is preferably substantially horizontal and inclined upward at least toward the downstream of the pressure loss element portion.
As described above, according to the present embodiment, the pressure loss of the bypass flow path 121 is made larger than the pressure loss element unit 110. This causes more anode off-gas to flow through the pressure loss element unit 110. The pressure loss of the condensed water flowing through the bypass flow path 121 is smaller than the pressure loss of the anode off-gas flowing through the pressure loss element 110. Thereby, the water condensed on the upstream side of the pressure loss element section 110 is discharged downstream through the bypass flow path 121. This allows condensed water accumulated upstream of the pressure loss element 110 to be discharged to the pressure loss element 110, thereby reducing the risk of rust formation upstream of the pressure loss element 110.
(sixth embodiment)
Fig. 9 is a structural diagram of a discharge flow path 10 of the sixth embodiment. Fig. 9 illustrates the discharge flow path 10 and the pressure loss element unit 110 with parts removed. As shown in fig. 9, the fuel cell system 1 of the present embodiment of the sixth embodiment is different from the fuel cell system 1 of the fifth embodiment in that it includes a mesh 122 having holes in a grid shape throughout the flow path cross section upstream of the pressure loss element portion 110. The size of the grid of the mesh 122 is smaller than the flow path diameter of the pressure loss element section 110.
As described above, according to the present embodiment, since the mesh 122 is disposed, water droplets larger than the lattice of the mesh are crushed and flow out vertically without reaching the pressure loss element portion 110. Further, since the flow path has holes in a grid shape in all cross sections, water droplets adhering to the inner periphery of the flow path can move on the inner periphery of the flow path without being blocked by the mesh 122. Thereby, the mesh 122 reduces the possibility that the pressure loss element portion 110 is closed by water droplets. The water droplets blocked by the mesh 122 can move around the inner periphery of the flow path and reach the bypass flow path 121. This prevents water droplets from accumulating in the discharge flow path 10, and reduces the risk of rust formation upstream of the pressure loss element section 110.
(modification 1)
Fig. 10 is a side view of an eccentric reducer. As shown in fig. 10, the present modification differs from the fuel cell system 1 of the first embodiment in that the pressure loss element section 110 is formed of an eccentric reducing pipe 123. Hereinafter, differences from the pressure loss element section 110 of the first to sixth embodiments will be described. The tube-tapering portion of the reducing tube constitutes a pressure loss element. Thus, no orifice formation is required. On the other hand, since a general reducing pipe is symmetrical about the central axis and is made thin, condensed water accumulates in thick piping, and the risk of rusting increases. When the eccentric reducing pipe 123 is used, the thick flow path and the thin flow path at the vertical lower end have the same height, and therefore, the condensate can be prevented from staying without providing a bypass flow path for the condensate. This prevents water droplets from accumulating in the discharge flow path 10, and reduces the risk of rust formation upstream of the pressure loss element section 110.
(seventh embodiment)
Fig. 11 is a configuration diagram of the entire fuel cell system of the seventh embodiment. As shown in fig. 11, the fuel cell system 1 of the present embodiment of the seventh embodiment differs from the fuel cell system 1 of the first embodiment in that a recycle gas pressure loss element unit 124 is provided in the recycle gas flow path 6 downstream of the branch unit 12.
The recirculated gas pressure loss element portion 124 becomes a pressure loss element of the recirculated gas blown from the blowing portion 106. This allows the pressure between the blower 106 and the recirculated gas pressure loss element 124 to be increased by a smaller amount of air flow. Therefore, the hydrogen gas supplied from hydrogen gas supply device 102 can be prevented from flowing into branching unit 8 while the amount of air blown by air blowing unit 106 is further suppressed. In this way, even if the recirculation gas flow path 6 is not provided with a check valve, the flow of the hydrogen-containing gas supplied from the hydrogen gas supply device 102 into the discharge flow path 10 can be suppressed, and the energy utilization efficiency of the entire fuel cell system 1 can be further improved.
According to at least one embodiment described above, the pressure loss of the recirculated gas flow path can be suppressed.
(modification 2)
Fig. 12 is a side view of an eccentric reducer using eccentric orifice 124. As shown in fig. 12, the present modification is different from the first to seventh embodiments in that the pressure loss element section 110 is constituted by an eccentric orifice 124. Differences from the pressure loss element section 110 of the first to seventh embodiments will be described below. Although a typical reducing pipe is symmetrically perforated about the central axis, the thick flow path at the vertical lower end of the eccentric orifice 124 is at the same height as the orifice perforation, and therefore, even if a bypass flow path for condensed water is not provided, the condensed water can be prevented from being retained. This prevents water droplets from accumulating in the discharge flow path 10, and reduces the risk of rust formation upstream of the pressure loss element section 110. The eccentric hole 124 is plate-shaped, and is fastened and fixed by bolts (not shown) via washers (not shown) by a flange 125 and a flange 126, and is sealed.
While several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.
Claims (14)
1. A fuel cell system is provided with:
a fuel cell having a fuel electrode channel for supplying a hydrogen-containing gas supplied from a hydrogen gas supply channel to a fuel electrode and an oxidant channel for supplying an oxygen-containing gas to an oxidant electrode, and generating power using the hydrogen-containing gas supplied to the fuel electrode and the oxygen-containing gas supplied to the oxidant electrode;
a blower unit provided in a recirculation gas flow path for returning anode off-gas discharged from the fuel electrode flow path through a junction with the hydrogen gas supply flow path, the blower unit sucking the anode off-gas from a downstream side of the fuel electrode flow path and discharging the anode off-gas to a downstream side of the recirculation gas flow path;
a discharge valve unit that opens and closes a discharge flow path that discharges a part of the anode off-gas from a branch portion provided between the blowing unit and the merging unit in the recirculation gas flow path;
a pressure loss element unit that is arranged between the branch portion of the discharge flow path and the discharge valve unit, and has a pressure loss greater than a pressure loss of the fuel electrode flow path in the fuel cell; and
and a control device for controlling the pressure at the outlet of the blowing section between the blowing section and the merging section of the recycle gas flow path to be higher than the pressure in the hydrogen gas supply flow path.
2. The fuel cell system according to claim 1,
the control device controls the blowing section such that a pressure at an outlet of the blowing section between the blowing section and the merging section of the recirculated gas flow path becomes higher than a pressure in the hydrogen gas supply flow path.
3. The fuel cell system according to claim 1,
the recirculation gas flow path further includes a condensation heat exchanger on an upstream side of the blowing section, the condensation heat exchanger liquefying and removing water vapor contained in the anode off-gas flowing through the recirculation gas flow path.
4. The fuel cell system according to claim 2,
the recirculation gas flow path further includes a condensation heat exchanger on an upstream side of the blowing section, the condensation heat exchanger liquefying and removing water vapor contained in the anode off-gas flowing through the recirculation gas flow path.
5. The fuel cell system according to claim 3 or 4,
further comprises a condensed water discharge part for discharging condensed water,
the air blowing unit is disposed above the condensation heat exchanger and the condensed water discharge unit.
6. The fuel cell system according to any one of claims 1 to 4, wherein the control device sets a rotation speed of the air blowing part as a function of the fuel cell.
7. The fuel cell system according to any one of claims 1 to 4,
the control device performs switching control of the discharge valve portion so as to alternately perform discharge control in which a part of the anode off-gas is discharged for a predetermined discharge time period and stop control in which the discharge of a part of the anode off-gas is stopped for a predetermined stop time period.
8. The fuel cell system according to claim 7,
the fuel cell is configured by stacking a plurality of fuel cells each having the fuel electrode and the oxidant electrode,
the control device performs the discharge control and the stop control based on at least one of a current value of the fuel cell, a power generation output, pressure information inside the fuel cell, a flow rate of the hydrogen-containing gas, a flow rate of the oxygen-containing gas, the number of the fuel cells included in the fuel cell, and an air utilization rate of the fuel cell.
9. The fuel cell system according to any one of claims 1 to 4,
the discharge flow path has a bypass flow path connecting upstream and downstream of the pressure loss element section,
the center of the opening on the upstream side of the bypass flow path is located in the vicinity of the lowest portion in the vertical direction of the discharge flow path.
10. The fuel cell system according to claim 9,
a pressure loss of the bypass passage when the anode off-gas flows therethrough is larger than a pressure loss when the anode off-gas flows therethrough in the pressure loss element section,
the pressure loss of the bypass flow path when the condensed water flows is smaller than the pressure loss when the anode off-gas flows through the pressure loss element.
11. The fuel cell system according to any one of claims 1 to 4,
the discharge flow path has a mesh having grid-shaped holes smaller in diameter than the flow path of the pressure loss element section in a flow path cross section on the upstream side of the pressure loss element section.
12. The fuel cell system according to any one of claims 1 to 4, wherein the pressure loss element portion is constituted by an eccentric reducer.
13. The fuel cell system according to any one of claims 1 to 4,
and a recirculation gas pressure loss element section provided between the branching section and the merging section.
14. A method for controlling a fuel cell system, the fuel cell system comprising:
a fuel cell having a fuel electrode channel for supplying a hydrogen-containing gas supplied from a hydrogen gas supply channel to a fuel electrode and an oxidant channel for supplying an oxygen-containing gas to an oxidant electrode, and generating power using the hydrogen-containing gas supplied to the fuel electrode and the oxygen-containing gas supplied to the oxidant electrode;
a blower unit provided in a recirculation gas flow path for returning anode off-gas discharged from the fuel electrode flow path through a junction with the hydrogen gas supply flow path, the blower unit sucking the anode off-gas from a downstream side of the fuel electrode flow path and discharging the anode off-gas to a downstream side of the recirculation gas flow path;
a discharge valve unit that opens and closes a discharge flow path that discharges a part of the anode off-gas from a branch portion provided between the blowing unit and the merging unit in the recirculation gas flow path; and
a pressure loss element unit disposed between the branch portion and the discharge valve unit of the discharge flow path, the pressure loss element unit having a pressure loss greater than a pressure loss of the fuel electrode flow path in the fuel cell, the method for controlling the fuel cell system including:
the blowing section is controlled so that the pressure at the outlet of the blowing section between the blowing section and the merging section of the recycle gas flow path is higher than the pressure in the hydrogen gas supply flow path.
Applications Claiming Priority (3)
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| JP2017235373 | 2017-12-07 | ||
| JP2017-235373 | 2017-12-07 | ||
| PCT/JP2018/044537 WO2019111886A1 (en) | 2017-12-07 | 2018-12-04 | Fuel cell system and control method for fuel cell system |
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| CN111801825A CN111801825A (en) | 2020-10-20 |
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| CN (1) | CN111801825B (en) |
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| JP2021005534A (en) * | 2019-06-27 | 2021-01-14 | 株式会社東芝 | Fuel cell system and control method therefor |
| JP7457561B2 (en) * | 2020-04-03 | 2024-03-28 | 株式会社東芝 | fuel cell power generator |
| CN112228331B (en) * | 2020-09-15 | 2022-03-15 | 武汉船用电力推进装置研究所（中国船舶重工集团公司第七一二研究所） | Hydrogen circulating pump capability test system |
| JP7331825B2 (en) * | 2020-12-10 | 2023-08-23 | トヨタ自動車株式会社 | fuel cell system |
| JP7415971B2 (en) * | 2021-02-08 | 2024-01-17 | トヨタ自動車株式会社 | fuel cell system |
| JP7400757B2 (en) * | 2021-03-05 | 2023-12-19 | トヨタ自動車株式会社 | fuel cell system |
| AT526262B1 (en) * | 2022-07-14 | 2024-07-15 | Avl List Gmbh | Temperature control housing for tempering components of a fuel cell system |
| CN115395056B (en) * | 2022-09-05 | 2024-09-27 | 浙江天能氢能源科技有限公司 | Fuel cell system with tail gas back pressure energy recovery device and control method |
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| WO2019111886A1 (en) | 2019-06-13 |
| DE112018006273T5 (en) | 2020-08-20 |
| JPWO2019111886A1 (en) | 2020-11-26 |
| JP6916901B2 (en) | 2021-08-11 |
| CN111801825A (en) | 2020-10-20 |
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