WO2011036766A1 - Fuel cell system - Google Patents

Fuel cell system Download PDF

Info

Publication number
WO2011036766A1
WO2011036766A1 PCT/JP2009/066638 JP2009066638W WO2011036766A1 WO 2011036766 A1 WO2011036766 A1 WO 2011036766A1 JP 2009066638 W JP2009066638 W JP 2009066638W WO 2011036766 A1 WO2011036766 A1 WO 2011036766A1
Authority
WO
WIPO (PCT)
Prior art keywords
fuel cell
film thickness
fuel
voltage
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2009/066638
Other languages
French (fr)
Japanese (ja)
Inventor
真明 松末
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to PCT/JP2009/066638 priority Critical patent/WO2011036766A1/en
Publication of WO2011036766A1 publication Critical patent/WO2011036766A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/04Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313Processes 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
    • H01M8/04537Electric variables
    • H01M8/04544Voltage
    • H01M8/04559Voltage of fuel cell stacks
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/04Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313Processes 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
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00Fuel cells; Manufacture thereof
    • H01M8/10Fuel cells with solid electrolytes
    • H01M2008/1095Fuel cells with polymeric electrolytes
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells

Definitions

  • the present invention relates to a fuel cell system that generates power by supplying a fuel gas containing hydrogen and an oxidizing gas to the fuel cell.
  • Examples of fuel cells that generate electricity using an electrochemical reaction between hydrogen and oxygen include solid polymer fuel cells.
  • the polymer electrolyte fuel cell includes a stack configured by stacking a plurality of cells.
  • a cell constituting the stack includes an anode (fuel electrode) and a cathode (air electrode), and a solid polymer electrolyte membrane having a sulfone sun group as an ion exchange group is interposed between the anode and the cathode. Intervene.
  • the fuel gas (reformed hydrogen obtained by reforming hydrogen gas or hydrocarbon to be hydrogen rich) is supplied to the anode, and the oxidizing gas containing oxygen as an oxidant (air as an example) is supplied to the cathode.
  • the oxidizing gas containing oxygen as an oxidant air as an example
  • the cathode By supplying the fuel gas to the anode, hydrogen contained in the fuel gas reacts with the catalyst of the catalyst layer constituting the anode, thereby generating hydrogen ions.
  • the generated hydrogen ions pass through the solid polymer electrolyte membrane and cause an electrical reaction with oxygen at the cathode. Power generation is performed by this electrochemical reaction (see, for example, Patent Document 1 below).
  • the single cell constituting the fuel cell is composed of a solid polymer electrolyte membrane
  • this film thickness becomes thinner as it deteriorates, and it is stable to accurately grasp the decrease in the film thickness. This is necessary for the operation of the fuel cell system.
  • the above-described conventional technique cannot grasp such a film thickness.
  • the present invention has been made in view of such problems, and an object thereof is to provide a fuel cell system capable of estimating the film thickness of a single cell constituting the fuel cell.
  • a fuel cell system is a fuel cell system in which a fuel gas containing hydrogen and an oxidizing gas are supplied to a fuel cell to generate electric power, and the open circuit voltage of the fuel cell is Voltage measuring means for measuring, and film thickness calculating means for calculating the film thickness of the single cell constituting the fuel cell based on the difference between the theoretical electromotive voltage of the fuel cell and the open circuit voltage measured by the voltage measuring device And a notifying means for notifying when the film thickness calculated by the film thickness calculating means is equal to or less than a predetermined limit film thickness.
  • the film thickness of the single cell constituting the fuel cell can be calculated. Further, when the calculated film thickness is equal to or less than a predetermined limit film thickness, it is possible to notify the user so that the user can recognize it, and to prompt the user to take measures such as replacement of the fuel cell.
  • FIG. 1 is a diagram showing a system configuration of a fuel cell system FCS that functions as an in-vehicle power supply system for a fuel cell vehicle.
  • the fuel cell system FCS can be mounted on a vehicle such as a fuel cell vehicle (FCHV), an electric vehicle, or a hybrid vehicle.
  • FCHV fuel cell vehicle
  • FCHV fuel cell vehicle
  • the fuel cell system FCS includes a fuel cell FC, an oxidizing gas supply system ASS, a fuel gas supply system FSS, a power system ES, a cooling system CS, and a controller EC.
  • the fuel cell FC is configured to generate electric power upon receiving a supply of reaction gas (fuel gas, oxidizing gas).
  • the oxidizing gas supply system ASS is a system for supplying air as an oxidizing gas to the fuel cell FC.
  • the fuel gas supply system FSS is a system for supplying hydrogen gas as fuel gas to the fuel cell FC.
  • the power system ES is a system for controlling charge / discharge of power.
  • the cooling system CS is a system for cooling the fuel cell FC.
  • the controller EC is a controller that performs overall control of the entire fuel cell system FCS.
  • the fuel cell FC is configured as a solid polymer electrolyte type cell stack in which a large number of cells (a single battery (a power generator) including an anode, a cathode, and an electrolyte) are stacked in series.
  • the fuel cell FC is provided with a temperature sensor and a gas flow rate sensor not shown in the figure.
  • the fuel cell FC undergoes an oxidation reaction of formula (1) at the anode and a reduction reaction of formula (2) at the cathode.
  • the fuel cell FC as a whole undergoes an electromotive reaction of the formula (3).
  • the oxidizing gas supply system ASS has an oxidizing gas passage AS3 and an oxidizing off gas passage AS4.
  • the oxidizing gas flow path AS3 is a flow path through which oxidizing gas supplied to the cathode of the fuel cell FC flows.
  • the oxidation off gas flow path AS4 is a flow path through which the oxidation off gas discharged from the fuel cell FC flows.
  • an air compressor AS2 and a humidifier AS5 are provided in the oxidizing gas flow path AS3.
  • the air compressor AS2 is a compressor for taking in the oxidizing gas from the atmosphere via the filter AS1.
  • the humidifier AS5 is a humidifier for humidifying the oxidizing gas pressurized by the air compressor AS2.
  • a pressure sensor S6 In the oxidation off gas flow path AS4, a pressure sensor S6, a back pressure adjustment valve A3, and a humidifier AS5 are provided.
  • the back pressure adjustment valve A3 is a valve for adjusting the oxidizing gas supply pressure.
  • the humidifier AS5 is provided for exchanging moisture between the oxidizing gas (dry gas) and the oxidizing off gas (wet gas).
  • the fuel gas supply system FSS has a fuel gas supply source FS1, a fuel gas flow path FS3, a circulation flow path FS4, a circulation pump FS5, and an exhaust drainage flow path FS6.
  • the fuel gas channel FS3 is a channel through which the fuel gas supplied from the fuel gas supply source FS1 to the anode of the fuel cell FC flows.
  • the circulation flow path FS4 is a flow path for returning the fuel off-gas discharged from the fuel cell FC to the fuel gas flow path FS3.
  • the circulation pump FS5 is a pump that pressure-feeds the fuel off-gas in the circulation flow path FS4 to the fuel gas flow path FS3.
  • the exhaust drainage channel FS6 is a channel that is branched and connected to the circulation channel FS4.
  • the fuel gas supply source FS1 is composed of, for example, a high-pressure hydrogen tank or a hydrogen storage alloy, and stores high-pressure (for example, 35 MPa to 70 MPa) hydrogen gas.
  • high-pressure hydrogen gas for example, 35 MPa to 70 MPa
  • the shutoff valve H1 When the shutoff valve H1 is opened, the fuel gas flows out from the fuel gas supply source FS1 to the fuel gas flow path FS3.
  • the fuel gas is decompressed to, for example, about 200 kPa by the regulator H2 and the injector FS2, and supplied to the fuel cell FC.
  • the fuel gas flow path FS3 is provided with a shutoff valve H1, a regulator H2, an injector FS2, a shutoff valve H3, and a pressure sensor S4.
  • the shutoff valve H1 is a valve for shutting off or allowing the supply of the fuel gas from the fuel gas supply source FS1.
  • the regulator H2 adjusts the pressure of the fuel gas.
  • the injector FS2 controls the amount of fuel gas supplied to the fuel cell FC.
  • the shutoff valve H3 is a valve for shutting off the fuel gas supply to the fuel cell FC.
  • the regulator H2 is a device that regulates the upstream side pressure (primary pressure) to a preset secondary pressure, and includes, for example, a mechanical pressure reducing valve that reduces the primary pressure.
  • the mechanical pressure reducing valve has a housing in which a back pressure chamber and a pressure adjusting chamber are formed with a diaphragm therebetween, and the primary pressure is reduced to a predetermined pressure in the pressure adjusting chamber by the back pressure in the back pressure chamber. It has a configuration for the next pressure.
  • the injector FS2 is an electromagnetically driven on-off valve capable of adjusting a gas flow rate and a gas pressure by driving a valve body directly with a predetermined driving cycle with an electromagnetic driving force and separating it from a valve seat.
  • the injector FS2 moves in an axial direction (gas flow direction) with respect to a valve seat having an injection hole for injecting gaseous fuel such as fuel gas, a nozzle body for supplying and guiding the gaseous fuel to the injection hole, and the nozzle body. And a valve body that is stored and held so as to open and close the injection hole.
  • the valve body of the injector FS2 is driven by a solenoid that is an electromagnetic drive device, and is configured such that the gas injection time and gas injection timing of the injector FS2 can be controlled by a control signal output from the controller EC.
  • Injector FS2 changes downstream by changing at least one of the opening area (opening) and the opening time of the valve provided in the gas flow path of injector FS2 in order to supply the required gas flow rate downstream.
  • the gas flow rate (or hydrogen molar concentration) supplied to the side is adjusted.
  • a shutoff valve H4 is provided, and an exhaust / drain channel FS6 is connected.
  • An exhaust / drain valve H5 is provided in the exhaust / drain flow path FS6.
  • the exhaust / drain valve H5 is a valve for discharging the fuel off-gas containing impurities in the circulation flow path FS4 and moisture to the outside by operating according to a command from the controller EC.
  • the fuel off-gas discharged through the exhaust / drain valve H5 is mixed with the oxidizing off-gas flowing through the oxidizing off-gas passage AS4 and diluted by a diluter (not shown).
  • the circulation pump FS5 circulates and supplies the fuel off gas in the circulation system to the fuel cell FC by driving the motor.
  • the power system ES includes a DC / DC converter ES1, a battery ES2, a traction inverter ES3, a traction motor ES4, and auxiliary machinery ES5.
  • the fuel cell system FCS is configured as a parallel hybrid system in which a DC / DC converter ES1 and a traction inverter ES3 are connected to the fuel cell FC in parallel.
  • the DC / DC converter ES1 boosts the DC voltage supplied from the battery ES2 and outputs it to the traction inverter ES3, and the DC power generated by the fuel cell FC or the regenerative power recovered by the traction motor ES4 by regenerative braking. It has a function of stepping down and charging the battery ES2.
  • the charging / discharging of the battery ES2 is controlled by these functions of the DC / DC converter ES1.
  • the operating point (output terminal voltage, output current) of the fuel cell FC is controlled by voltage conversion control by the DC / DC converter ES1.
  • a voltage sensor S1 and a current sensor S2 are attached to the fuel cell FC.
  • the voltage sensor S1 is a sensor for detecting the output terminal voltage of the fuel cell FC.
  • the current sensor S2 is a sensor for detecting the output current of the fuel cell FC.
  • the battery ES2 functions as a surplus power storage source, a regenerative energy storage source during regenerative braking, and an energy buffer during load fluctuations associated with acceleration or deceleration of the fuel cell vehicle.
  • a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery is preferable.
  • An SOC sensor S3 for detecting SOC (State of charge) is attached to the battery ES2.
  • the traction inverter ES3 is, for example, a PWM inverter driven by a pulse width modulation method.
  • the traction inverter ES3 converts the DC voltage output from the fuel cell FC or the battery ES2 into a three-phase AC voltage according to a control command from the controller EC, and controls the rotational torque of the traction motor ES4.
  • the traction motor ES4 is a three-phase AC motor, for example, and constitutes a power source of the fuel cell vehicle.
  • Auxiliary machinery ES5 includes motors (for example, power sources such as pumps) arranged in each part in the fuel cell system FCS, inverters for driving these motors, and various in-vehicle auxiliary machinery (for example, an air compressor, an injector, a cooling water circulation pump, a radiator, etc.) are collectively referred to.
  • motors for example, power sources such as pumps
  • inverters for driving these motors
  • various in-vehicle auxiliary machinery For example, an air compressor, an injector, a cooling water circulation pump, a radiator, etc.
  • the cooling system CS includes a radiator CS1, a coolant pump CS2, a coolant forward path CS3, and a coolant return path CS4.
  • the radiator CS1 radiates and cools the coolant for cooling the fuel cell FC.
  • the coolant pump CS2 is a pump for circulating the coolant between the fuel cell FC and the radiator CS1.
  • the coolant forward path CS3 is a channel connecting the radiator CS1 and the fuel cell FC, and is provided with a coolant pump CS2. When the coolant pump CS2 is driven, the coolant flows from the radiator CS1 to the fuel cell FC through the coolant forward path CS3.
  • the coolant return path CS4 is a flow path connecting the fuel cell FC and the radiator CS1, and is provided with a water temperature sensor S5.
  • the coolant pump CS2 When the coolant pump CS2 is driven, the coolant that has cooled the fuel cell FC returns to the radiator CS1.
  • the controller EC (control unit) is a computer system including a CPU, a ROM, a RAM, and an input / output interface, and controls each unit of the fuel cell system FCS. For example, the controller EC starts the operation of the fuel cell system FCS when receiving the start signal IG output from the ignition switch. Thereafter, the controller EC obtains the required power of the entire fuel cell system FCS based on the accelerator opening signal ACC output from the accelerator sensor, the vehicle speed signal VC output from the vehicle speed sensor, and the like. The required power of the entire fuel cell system FCS is the total value of the vehicle travel power and the auxiliary power.
  • auxiliary electric power includes electric power consumed by in-vehicle auxiliary equipment (humidifier, air compressor, hydrogen pump, cooling water circulation pump, etc.), and equipment required for vehicle travel (transmission, wheel control device, steering) Power consumed by devices, suspension devices, etc.), power consumed by devices (air conditioners, lighting equipment, audio, etc.) disposed in the passenger space, and the like.
  • in-vehicle auxiliary equipment humidity, air compressor, hydrogen pump, cooling water circulation pump, etc.
  • equipment required for vehicle travel transmission, wheel control device, steering
  • devices air conditioners, lighting equipment, audio, etc.
  • the controller EC determines the distribution of the respective output powers of the fuel cell FC and the battery ES2.
  • the controller EC controls the oxidizing gas supply system ASS and the fuel gas supply system FSS so that the power generation amount of the fuel cell FC matches the target power, and also controls the DC / DC converter ES1 to operate the fuel cell FC.
  • Control points output terminal voltage, output current).
  • the controller EC outputs, for example, each U-phase, V-phase, and W-phase AC voltage command value to the traction inverter ES3 as a switching command so as to obtain a target torque corresponding to the accelerator opening, Controls the output torque and rotation speed of the motor ES4.
  • the controller EC controls the cooling system CS so that the fuel cell FC has an appropriate temperature.
  • the fuel cell system FCS of the present embodiment has the above-described configuration, voltage calculation means EC1 for calculating the theoretical electromotive voltage of the fuel cell FC, voltage measurement means EC2 for measuring the open circuit voltage of the fuel cell FC, and voltage calculation means. Based on the difference between the theoretical electromotive voltage calculated by EC1 and the open circuit voltage measured by the voltage measuring means EC2, the film thickness calculating means EC3 for calculating the film thickness of the single cell constituting the fuel cell FC, and the membrane pressure calculating means It functions as a fuel cell system provided with notifying means EC4 for notifying when the film thickness calculated by EC3 is not more than a predetermined limit film thickness. Therefore, the controller EC functions as voltage calculation means EC1, voltage measurement means EC2, membrane pressure calculation means EC3, and notification means EC4.
  • FIG. 2 is a flowchart showing a flow for calculating the film thickness of the single cells constituting the fuel cell FC in the fuel cell system FCS of the present embodiment.
  • the voltage measuring means EC2 measures the open circuit voltage (OCV: Open Circuit Voltage) of the fuel cell FC.
  • OCV Open Circuit Voltage
  • the OC state is temporarily set to detect the film thickness. Transition. When the OC avoidance state continues for a certain time or more, the same condition is easily formed, and the film thickness detection accuracy is further improved by shifting to the OC state from there.
  • step S02 following step S01 the film thickness calculation means EC3 calculates the film thickness of the single cells constituting the fuel cell FC.
  • the voltage calculation means EC1 calculates the theoretical electromotive voltage of the fuel cell FC.
  • the theoretical electromotive voltage E of a single cell is obtained by equation (4).
  • E - ⁇ g f / 2F (4)
  • ⁇ g f is Gibbs free energy and F is a Faraday constant. For a single cell operating below 100 ° C., this value is about 1.2V. Accordingly, the theoretical electromotive voltage of the fuel cell FC is obtained from this value and the number of cells. For this reason, the theoretical electromotive voltage may be calculated each time by the voltage calculation means EC1, or may be determined in advance based on the specifications of the fuel cell FC.
  • Equation (5) which is the difference between the theoretical electromotive voltage and the open circuit voltage, is expressed by Equation (5).
  • ⁇ V RT / 2 ⁇ F ⁇ ln (i cross / i) (5)
  • R is a gas constant
  • F is a Faraday constant
  • is a charge transfer coefficient.
  • the charge transfer coefficient ⁇ is a coefficient determined by the catalyst used in the fuel cell FC.
  • i is an output current
  • i cross is an internal current due to a fuel gas cross leak.
  • the right side of Equation (5) is a constant other than the internal current i cross due to fuel gas cross leak. Therefore, the internal current i cross can be obtained from ⁇ V.
  • i cross Q cross ⁇ 2F (6)
  • Q cross a ⁇ P H2 ⁇ S / L (7)
  • Q cross is a gas cross leak amount
  • a is a film physical property value
  • P H2 is a hydrogen partial pressure
  • S is a film area of a single cell
  • L is a film thickness of the single cell.
  • the film thickness calculation means EC3 calculates the film thickness L based on the equations (5), (6), and (7).
  • step S03 it is determined whether the film thickness L obtained in step S02 is less than a predetermined limit film thickness L '.
  • This limit film thickness L ′ is determined in advance from the strength of the film. If the calculated film thickness L is less than the limit film thickness L ′, the process proceeds to step S ⁇ b> 04. If the calculated film thickness L is not less than the limit film thickness L ′, the process ends.
  • step S04 the notification means EC4 notifies that the fuel cell FC has deteriorated so that it can be recognized by the user via an alert lamp or a speaker.
  • FCS Fuel cell system FC: Fuel cell ASS: Oxidizing gas supply system AS1: Filter AS2: Air compressor AS3: Oxidizing gas channel AS4: Oxidizing off gas channel AS5: Humidifier A3: Back pressure regulating valve CS: Cooling system CS1: Radiator CS2: Coolant pump CS3: Coolant forward path CS4: Coolant return path FSS: Fuel gas supply system FS1: Fuel gas supply source FS2: Injector FS3: Fuel gas channel FS4: Circulation channel FS5: Circulation pump FS6: Exhaust drainage Flow path H1: Shut-off valve H2: Regulator H3: Shut-off valve H4: Shut-off valve H5: Exhaust drain valve ES: Power system ES1: DC / DC converter ES2: Battery ES3: Traction inverter ES4: Traction motor ES5: Auxiliary equipment EC: Controller S1: Voltage sensor S2: Current sensor S3: S

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Fuel Cell (AREA)

Abstract

Disclosed is a fuel cell system (FCS) which comprises: a voltage measuring means (EC2) for measuring the open circuit voltage of an fuel cell (FC); a film thickness calculating means (EC3) for calculating the film thickness of a unit cell constituting the fuel cell (FC) on the basis of the difference between the theoretical electromotive voltage of the fuel cell (FC) and the open circuit voltage measured by the voltage measuring means (EC2); and an informing means (EC4) for informing of the case when the film thickness calculated by the film thickness calculating means (EC3) is equal to or less than a predetermined limit film thickness.

Description

燃料電池システムFuel cell system

 本発明は、燃料電池に水素を含む燃料ガスと酸化ガスとを供給して発電させる燃料電池システムに関する。 The present invention relates to a fuel cell system that generates power by supplying a fuel gas containing hydrogen and an oxidizing gas to the fuel cell.

 水素と酸素との電気化学反応を利用して発電する燃料電池としては、例えば、固体高分子型燃料電池がある。この固体高分子型燃料電池は、複数のセルを積層して構成されたスタックを備えている。スタックを構成するセルは、アノード(燃料極)とカソード(空気極)とを備えており、これらのアノードとカソードとの間には、イオン交換基としてスルフォンサン基を有する固体高分子電解質膜が介在している。 Examples of fuel cells that generate electricity using an electrochemical reaction between hydrogen and oxygen include solid polymer fuel cells. The polymer electrolyte fuel cell includes a stack configured by stacking a plurality of cells. A cell constituting the stack includes an anode (fuel electrode) and a cathode (air electrode), and a solid polymer electrolyte membrane having a sulfone sun group as an ion exchange group is interposed between the anode and the cathode. Intervene.

 アノードには燃料ガス(水素ガスまたは炭化水素を改質して水素リッチにした改質水素)が供給され、カソードには酸化剤として酸素を含む酸化ガス(一例として空気)が供給される。アノードに燃料ガスが供給されることで、燃料ガスに含まれる水素がアノードを構成する触媒層の触媒と反応し、これによって水素イオンが発生する。発生した水素イオンは固体高分子電解質膜を通過して、カソードで酸素と電気反応を起こす。この電気化学反応によって発電が行われる構成となっている(例えば、下記特許文献1参照)。 The fuel gas (reformed hydrogen obtained by reforming hydrogen gas or hydrocarbon to be hydrogen rich) is supplied to the anode, and the oxidizing gas containing oxygen as an oxidant (air as an example) is supplied to the cathode. By supplying the fuel gas to the anode, hydrogen contained in the fuel gas reacts with the catalyst of the catalyst layer constituting the anode, thereby generating hydrogen ions. The generated hydrogen ions pass through the solid polymer electrolyte membrane and cause an electrical reaction with oxygen at the cathode. Power generation is performed by this electrochemical reaction (see, for example, Patent Document 1 below).

特開2008-269813号公報JP 2008-269813 A

 ところで、燃料電池を構成する単セルは固体高分子電解質膜によって構成されるけれども、この膜厚は劣化に伴って薄くなるものであって、その膜厚の減少を的確に把握することは安定した燃料電池システムの運用に必要なものである。しかしながら、上述した従来の技術では、そのような膜厚を把握することができなかった。 By the way, although the single cell constituting the fuel cell is composed of a solid polymer electrolyte membrane, this film thickness becomes thinner as it deteriorates, and it is stable to accurately grasp the decrease in the film thickness. This is necessary for the operation of the fuel cell system. However, the above-described conventional technique cannot grasp such a film thickness.

 本発明はこのような課題に鑑みてなされたものであり、その目的は、燃料電池を構成する単セルの膜厚を推定することができる燃料電池システムを提供することにある。 The present invention has been made in view of such problems, and an object thereof is to provide a fuel cell system capable of estimating the film thickness of a single cell constituting the fuel cell.

 上記課題を解決するために本発明に係る燃料電池システムは、燃燃料電池に水素を含む燃料ガスと酸化ガスとを供給して発電させる燃料電池システムであって、前記燃料電池の開回路電圧を計測する電圧計測手段と、前記燃料電池の理論起電圧と前記電圧計測手段が計測した開回路電圧との差に基づいて、前記燃料電池を構成する単セルの膜厚を算出する膜厚算出手段と、前記膜厚算出手段が算出した膜厚が所定の限界膜厚以下の場合に報知する報知手段と、を備えることを特徴とする。 In order to solve the above-described problems, a fuel cell system according to the present invention is a fuel cell system in which a fuel gas containing hydrogen and an oxidizing gas are supplied to a fuel cell to generate electric power, and the open circuit voltage of the fuel cell is Voltage measuring means for measuring, and film thickness calculating means for calculating the film thickness of the single cell constituting the fuel cell based on the difference between the theoretical electromotive voltage of the fuel cell and the open circuit voltage measured by the voltage measuring device And a notifying means for notifying when the film thickness calculated by the film thickness calculating means is equal to or less than a predetermined limit film thickness.

 本発明によれば、電圧算出手段が算出した理論起電圧と電圧計測手段が計測した開回路電圧との差に基づいて、燃料電池を構成する単セルの膜厚を算出することができる。また、そのように算出した膜厚が所定の限界膜厚以下の場合には、ユーザに認識可能なように報知することができ、燃料電池の交換といった対策を講じるように促すことができる。 According to the present invention, based on the difference between the theoretical electromotive voltage calculated by the voltage calculating means and the open circuit voltage measured by the voltage measuring means, the film thickness of the single cell constituting the fuel cell can be calculated. Further, when the calculated film thickness is equal to or less than a predetermined limit film thickness, it is possible to notify the user so that the user can recognize it, and to prompt the user to take measures such as replacement of the fuel cell.

 本発明によれば、燃料電池を構成する単セルの膜厚を推定することができる燃料電池システムを提供することができる。 According to the present invention, it is possible to provide a fuel cell system capable of estimating the thickness of a single cell constituting a fuel cell.

本発明の実施形態である燃料電池車両に搭載される燃料電池システムの構成を示す図である。It is a figure which shows the structure of the fuel cell system mounted in the fuel cell vehicle which is embodiment of this invention. 図1に示す燃料電池システムに用いられる燃料電池の単セル膜厚を推定するフローチャートである。It is a flowchart which estimates the single cell film thickness of the fuel cell used for the fuel cell system shown in FIG.

 以下、添付図面を参照しながら本発明の実施の形態について説明する。説明の理解を容易にするため、各図面において同一の構成要素に対しては可能な限り同一の符号を付して、重複する説明は省略する。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

 最初に、本発明の実施形態である燃料電池車両に搭載される燃料電池システムFCSについて図1を参照しながら説明する。図1は燃料電池車両の車載電源システムとして機能する燃料電池システムFCSのシステム構成を示す図である。燃料電池システムFCSは、燃料電池自動車(FCHV)、電気自動車、ハイブリッド自動車などの車両に搭載することができる。 First, a fuel cell system FCS mounted on a fuel cell vehicle according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a system configuration of a fuel cell system FCS that functions as an in-vehicle power supply system for a fuel cell vehicle. The fuel cell system FCS can be mounted on a vehicle such as a fuel cell vehicle (FCHV), an electric vehicle, or a hybrid vehicle.

 燃料電池システムFCSは、燃料電池FCと、酸化ガス供給系ASSと、燃料ガス供給系FSSと、電力系ESと、冷却系CSと、コントローラECとを備えている。燃料電池FCは、反応ガス(燃料ガス、酸化ガス)の供給を受けて発電するものである。酸化ガス供給系ASSは、酸化ガスとしての空気を燃料電池FCに供給するための系である。燃料ガス供給系FSSは、燃料ガスとしての水素ガスを燃料電池FCに供給するための系である。電力系ESは、電力の充放電を制御するための系である。冷却系CSは、燃料電池FCを冷却するための系である。コントローラECは、燃料電池システムFCS全体を統括制御するコントローラである。 The fuel cell system FCS includes a fuel cell FC, an oxidizing gas supply system ASS, a fuel gas supply system FSS, a power system ES, a cooling system CS, and a controller EC. The fuel cell FC is configured to generate electric power upon receiving a supply of reaction gas (fuel gas, oxidizing gas). The oxidizing gas supply system ASS is a system for supplying air as an oxidizing gas to the fuel cell FC. The fuel gas supply system FSS is a system for supplying hydrogen gas as fuel gas to the fuel cell FC. The power system ES is a system for controlling charge / discharge of power. The cooling system CS is a system for cooling the fuel cell FC. The controller EC is a controller that performs overall control of the entire fuel cell system FCS.

 燃料電池FCは、多数のセル(アノード、カソード、及び電解質を備える単一の電池(発電体))を直列に積層してなる固体高分子電解質形のセルスタックとして構成されている。燃料電池FCには、図に明示しない温度センサ及びガス流量センサが設けられている。燃料電池FCでは、通常の運転において、アノードにおいて(1)式の酸化反応が生じ、カソードにおいて(2)式の還元反応が生じる。燃料電池FC全体としては(3)式の起電反応が生じる。 The fuel cell FC is configured as a solid polymer electrolyte type cell stack in which a large number of cells (a single battery (a power generator) including an anode, a cathode, and an electrolyte) are stacked in series. The fuel cell FC is provided with a temperature sensor and a gas flow rate sensor not shown in the figure. In a normal operation, the fuel cell FC undergoes an oxidation reaction of formula (1) at the anode and a reduction reaction of formula (2) at the cathode. The fuel cell FC as a whole undergoes an electromotive reaction of the formula (3).

 H2→2H++2e-           (1)
(1/2)O2+2H++2e-→H2O    (2)
2+(1/2)O2→H2O        (3)
H 2 → 2H + + 2e (1)
(1/2) O 2 + 2H + + 2e → H 2 O (2)
H 2 + (1/2) O 2 → H 2 O (3)

 酸化ガス供給系ASSは、酸化ガス流路AS3と酸化オフガス流路AS4とを有している。酸化ガス流路AS3は、燃料電池FCのカソードに供給される酸化ガスが流れる流路である。酸化オフガス流路AS4は、燃料電池FCから排出される酸化オフガスが流れる流路である。 The oxidizing gas supply system ASS has an oxidizing gas passage AS3 and an oxidizing off gas passage AS4. The oxidizing gas flow path AS3 is a flow path through which oxidizing gas supplied to the cathode of the fuel cell FC flows. The oxidation off gas flow path AS4 is a flow path through which the oxidation off gas discharged from the fuel cell FC flows.

 酸化ガス流路AS3には、エアコンプレッサAS2と、加湿器AS5とが設けられている。エアコンプレッサAS2は、フィルタAS1を介して大気中から酸化ガスを取り込むためのコンプレッサである。加湿器AS5は、エアコンプレッサAS2により加圧される酸化ガスを加湿するための加湿器である。 In the oxidizing gas flow path AS3, an air compressor AS2 and a humidifier AS5 are provided. The air compressor AS2 is a compressor for taking in the oxidizing gas from the atmosphere via the filter AS1. The humidifier AS5 is a humidifier for humidifying the oxidizing gas pressurized by the air compressor AS2.

 酸化オフガス流路AS4には、圧力センサS6と、背圧調整弁A3と、加湿器AS5とが設けられている。背圧調整弁A3は、酸化ガス供給圧を調整するための弁である。加湿器AS5は、酸化ガス(ドライガス)と酸化オフガス(ウェットガス)との間で水分交換するためのものとして設けられている。 In the oxidation off gas flow path AS4, a pressure sensor S6, a back pressure adjustment valve A3, and a humidifier AS5 are provided. The back pressure adjustment valve A3 is a valve for adjusting the oxidizing gas supply pressure. The humidifier AS5 is provided for exchanging moisture between the oxidizing gas (dry gas) and the oxidizing off gas (wet gas).

 燃料ガス供給系FSSは、燃料ガス供給源FS1と、燃料ガス流路FS3と、循環流路FS4と、循環ポンプFS5と、排気排水流路FS6とを有している。燃料ガス流路FS3は、燃料ガス供給源FS1から燃料電池FCのアノードに供給される燃料ガスが流れる流路である。循環流路FS4は、燃料電池FCから排出される燃料オフガスを燃料ガス流路FS3に帰還させるための流路である。循環ポンプFS5は、循環流路FS4内の燃料オフガスを燃料ガス流路FS3に圧送するポンプである。排気排水流路FS6は、循環流路FS4に分岐接続される流路である。 The fuel gas supply system FSS has a fuel gas supply source FS1, a fuel gas flow path FS3, a circulation flow path FS4, a circulation pump FS5, and an exhaust drainage flow path FS6. The fuel gas channel FS3 is a channel through which the fuel gas supplied from the fuel gas supply source FS1 to the anode of the fuel cell FC flows. The circulation flow path FS4 is a flow path for returning the fuel off-gas discharged from the fuel cell FC to the fuel gas flow path FS3. The circulation pump FS5 is a pump that pressure-feeds the fuel off-gas in the circulation flow path FS4 to the fuel gas flow path FS3. The exhaust drainage channel FS6 is a channel that is branched and connected to the circulation channel FS4.

 燃料ガス供給源FS1は、例えば、高圧水素タンクや水素吸蔵合金などで構成され、高圧(例えば、35MPa~70MPa)の水素ガスを貯蔵するものである。遮断弁H1を開くと、燃料ガス供給源FS1から燃料ガス流路FS3に燃料ガスが流出する。燃料ガスは、レギュレータH2やインジェクタFS2により、例えば、200kPa程度まで減圧されて、燃料電池FCに供給される。 The fuel gas supply source FS1 is composed of, for example, a high-pressure hydrogen tank or a hydrogen storage alloy, and stores high-pressure (for example, 35 MPa to 70 MPa) hydrogen gas. When the shutoff valve H1 is opened, the fuel gas flows out from the fuel gas supply source FS1 to the fuel gas flow path FS3. The fuel gas is decompressed to, for example, about 200 kPa by the regulator H2 and the injector FS2, and supplied to the fuel cell FC.

 燃料ガス流路FS3には、遮断弁H1と、レギュレータH2と、インジェクタFS2と、遮断弁H3と、圧力センサS4とが設けられている。遮断弁H1は、燃料ガス供給源FS1からの燃料ガスの供給を遮断又は許容するための弁である。レギュレータH2は、燃料ガスの圧力を調整するものである。インジェクタFS2は、燃料電池FCへの燃料ガス供給量を制御するものである。遮断弁H3は、燃料電池FCへの燃料ガス供給を遮断するための弁である。 The fuel gas flow path FS3 is provided with a shutoff valve H1, a regulator H2, an injector FS2, a shutoff valve H3, and a pressure sensor S4. The shutoff valve H1 is a valve for shutting off or allowing the supply of the fuel gas from the fuel gas supply source FS1. The regulator H2 adjusts the pressure of the fuel gas. The injector FS2 controls the amount of fuel gas supplied to the fuel cell FC. The shutoff valve H3 is a valve for shutting off the fuel gas supply to the fuel cell FC.

 レギュレータH2は、その上流側圧力(一次圧)を、予め設定した二次圧に調圧する装置であり、例えば、一次圧を減圧する機械式の減圧弁などで構成される。機械式の減圧弁は、背圧室と調圧室とがダイアフラムを隔てて形成された筺体を有し、背圧室内の背圧により調圧室内で一次圧を所定の圧力に減圧して二次圧とする構成を有する。インジェクタFS2の上流側にレギュレータH2を配置することにより、インジェクタFS2の上流側圧力を効果的に低減させることができる。 The regulator H2 is a device that regulates the upstream side pressure (primary pressure) to a preset secondary pressure, and includes, for example, a mechanical pressure reducing valve that reduces the primary pressure. The mechanical pressure reducing valve has a housing in which a back pressure chamber and a pressure adjusting chamber are formed with a diaphragm therebetween, and the primary pressure is reduced to a predetermined pressure in the pressure adjusting chamber by the back pressure in the back pressure chamber. It has a configuration for the next pressure. By arranging the regulator H2 on the upstream side of the injector FS2, the upstream pressure of the injector FS2 can be effectively reduced.

 インジェクタFS2は、弁体を電磁駆動力で直接的に所定の駆動周期で駆動して弁座から離隔させることによりガス流量やガス圧を調整することが可能な電磁駆動式の開閉弁である。インジェクタFS2は、燃料ガス等の気体燃料を噴射する噴射孔を有する弁座と、その気体燃料を噴射孔まで供給案内するノズルボディと、このノズルボディに対して軸線方向(気体流れ方向)に移動可能に格納保持され噴射孔を開閉する弁体とを備えている。 The injector FS2 is an electromagnetically driven on-off valve capable of adjusting a gas flow rate and a gas pressure by driving a valve body directly with a predetermined driving cycle with an electromagnetic driving force and separating it from a valve seat. The injector FS2 moves in an axial direction (gas flow direction) with respect to a valve seat having an injection hole for injecting gaseous fuel such as fuel gas, a nozzle body for supplying and guiding the gaseous fuel to the injection hole, and the nozzle body. And a valve body that is stored and held so as to open and close the injection hole.

 インジェクタFS2の弁体は電磁駆動装置であるソレノイドにより駆動され、コントローラECから出力される制御信号によってインジェクタFS2のガス噴射時間及びガス噴射時期を制御することが可能なように構成されている。インジェクタFS2は、その下流に要求されるガス流量を供給するために、インジェクタFS2のガス流路に設けられた弁体の開口面積(開度)及び開放時間の少なくとも一方を変更することにより、下流側に供給されるガス流量(又は水素モル濃度)を調整する。 The valve body of the injector FS2 is driven by a solenoid that is an electromagnetic drive device, and is configured such that the gas injection time and gas injection timing of the injector FS2 can be controlled by a control signal output from the controller EC. Injector FS2 changes downstream by changing at least one of the opening area (opening) and the opening time of the valve provided in the gas flow path of injector FS2 in order to supply the required gas flow rate downstream. The gas flow rate (or hydrogen molar concentration) supplied to the side is adjusted.

 循環流路FS4には、遮断弁H4が設けられ、排気排水流路FS6が接続されている。排気排水流路FS6には、排気排水弁H5が設けられている。排気排水弁H5は、コントローラECからの指令によって作動することにより、循環流路FS4内の不純物を含む燃料オフガスと水分とを外部に排出するための弁である。排気排水弁H5の開弁により、循環流路FS4内の燃料オフガス中の不純物の濃度が下がり、循環系内を循環する燃料オフガス中の水素濃度を上げることができる。 In the circulation channel FS4, a shutoff valve H4 is provided, and an exhaust / drain channel FS6 is connected. An exhaust / drain valve H5 is provided in the exhaust / drain flow path FS6. The exhaust / drain valve H5 is a valve for discharging the fuel off-gas containing impurities in the circulation flow path FS4 and moisture to the outside by operating according to a command from the controller EC. By opening the exhaust / drain valve H5, the concentration of impurities in the fuel off-gas in the circulation flow path FS4 is reduced, and the hydrogen concentration in the fuel off-gas circulating in the circulation system can be increased.

 排気排水弁H5を介して排出される燃料オフガスは、酸化オフガス流路AS4を流れる酸化オフガスと混合され、希釈器(図示せず)によって希釈される。循環ポンプFS5は、循環系内の燃料オフガスをモータ駆動により燃料電池FCに循環供給する。 The fuel off-gas discharged through the exhaust / drain valve H5 is mixed with the oxidizing off-gas flowing through the oxidizing off-gas passage AS4 and diluted by a diluter (not shown). The circulation pump FS5 circulates and supplies the fuel off gas in the circulation system to the fuel cell FC by driving the motor.

 電力系ESは、DC/DCコンバータES1と、バッテリES2と、トラクションインバータES3と、トラクションモータES4と、補機類ES5とを備えている。燃料電池システムFCSは、DC/DCコンバータES1とトラクションインバータES3とが並列に燃料電池FCに接続するパラレルハイブリッドシステムとして構成されている。 The power system ES includes a DC / DC converter ES1, a battery ES2, a traction inverter ES3, a traction motor ES4, and auxiliary machinery ES5. The fuel cell system FCS is configured as a parallel hybrid system in which a DC / DC converter ES1 and a traction inverter ES3 are connected to the fuel cell FC in parallel.

 DC/DCコンバータES1は、バッテリES2から供給される直流電圧を昇圧してトラクションインバータES3に出力する機能と、燃料電池FCが発電した直流電力、又は回生制動によりトラクションモータES4が回収した回生電力を降圧してバッテリES2に充電する機能とを有する。DC/DCコンバータES1のこれらの機能により、バッテリES2の充放電が制御される。また、DC/DCコンバータES1による電圧変換制御により、燃料電池FCの運転ポイント(出力端子電圧、出力電流)が制御される。燃料電池FCには、電圧センサS1と電流センサS2とが取り付けられている。電圧センサS1は、燃料電池FCの出力端子電圧を検出するためのセンサである。電流センサS2は、燃料電池FCの出力電流を検出するためのセンサである。 The DC / DC converter ES1 boosts the DC voltage supplied from the battery ES2 and outputs it to the traction inverter ES3, and the DC power generated by the fuel cell FC or the regenerative power recovered by the traction motor ES4 by regenerative braking. It has a function of stepping down and charging the battery ES2. The charging / discharging of the battery ES2 is controlled by these functions of the DC / DC converter ES1. Further, the operating point (output terminal voltage, output current) of the fuel cell FC is controlled by voltage conversion control by the DC / DC converter ES1. A voltage sensor S1 and a current sensor S2 are attached to the fuel cell FC. The voltage sensor S1 is a sensor for detecting the output terminal voltage of the fuel cell FC. The current sensor S2 is a sensor for detecting the output current of the fuel cell FC.

 バッテリES2は、余剰電力の貯蔵源、回生制動時の回生エネルギー貯蔵源、燃料電池車両の加速又は減速に伴う負荷変動時のエネルギーバッファとして機能する。バッテリES2としては、例えば、ニッケル・カドミウム蓄電池、ニッケル・水素蓄電池、リチウム二次電池等の二次電池が好適である。バッテリES2には、SOC(State of charge)を検出するためのSOCセンサS3が取り付けられている。 The battery ES2 functions as a surplus power storage source, a regenerative energy storage source during regenerative braking, and an energy buffer during load fluctuations associated with acceleration or deceleration of the fuel cell vehicle. As the battery ES2, for example, a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery is preferable. An SOC sensor S3 for detecting SOC (State of charge) is attached to the battery ES2.

 トラクションインバータES3は、例えば、パルス幅変調方式で駆動されるPWMインバータである。トラクションインバータES3は、コントローラECからの制御指令に従って、燃料電池FC又はバッテリES2から出力される直流電圧を三相交流電圧に変換して、トラクションモータES4の回転トルクを制御する。トラクションモータES4は、例えば、三相交流モータであり、燃料電池車両の動力源を構成する。 The traction inverter ES3 is, for example, a PWM inverter driven by a pulse width modulation method. The traction inverter ES3 converts the DC voltage output from the fuel cell FC or the battery ES2 into a three-phase AC voltage according to a control command from the controller EC, and controls the rotational torque of the traction motor ES4. The traction motor ES4 is a three-phase AC motor, for example, and constitutes a power source of the fuel cell vehicle.

 補機類ES5は、燃料電池システムFCS内の各部に配置されている各モータ(例えば、ポンプ類などの動力源)、これらのモータを駆動するためのインバータ類、及び各種の車載補機類(例えば、エアコンプレッサ、インジェクタ、冷却水循環ポンプ、ラジエータなど)を総称するものである。 Auxiliary machinery ES5 includes motors (for example, power sources such as pumps) arranged in each part in the fuel cell system FCS, inverters for driving these motors, and various in-vehicle auxiliary machinery ( For example, an air compressor, an injector, a cooling water circulation pump, a radiator, etc.) are collectively referred to.

 冷却系CSは、ラジエータCS1と、冷却液ポンプCS2と、冷却液往路CS3と、冷却液復路CS4とを有している。ラジエータCS1は、燃料電池FCを冷却するための冷却液を放熱して冷却するものである。冷却液ポンプCS2は、冷却液を燃料電池FCとラジエータCS1との間で循環させるためのポンプである。冷却液往路CS3は、ラジエータCS1と燃料電池FCとを繋ぐ流路であって、冷却液ポンプCS2が設けられている。冷却液ポンプCS2が駆動することで、冷却液はラジエータCS1から燃料電池FCへと冷却液往路CS3を通って流れる。冷却液復路CS4は、燃料電池FCとラジエータCS1とを繋ぐ流路であって、水温センサS5が設けられている。冷却液ポンプCS2が駆動することで、燃料電池FCを冷却した冷却液はラジエータCS1へと還流する。 The cooling system CS includes a radiator CS1, a coolant pump CS2, a coolant forward path CS3, and a coolant return path CS4. The radiator CS1 radiates and cools the coolant for cooling the fuel cell FC. The coolant pump CS2 is a pump for circulating the coolant between the fuel cell FC and the radiator CS1. The coolant forward path CS3 is a channel connecting the radiator CS1 and the fuel cell FC, and is provided with a coolant pump CS2. When the coolant pump CS2 is driven, the coolant flows from the radiator CS1 to the fuel cell FC through the coolant forward path CS3. The coolant return path CS4 is a flow path connecting the fuel cell FC and the radiator CS1, and is provided with a water temperature sensor S5. When the coolant pump CS2 is driven, the coolant that has cooled the fuel cell FC returns to the radiator CS1.

 コントローラEC(制御部)は、CPU、ROM、RAM、及び入出力インタフェースを備えるコンピュータシステムであり、燃料電池システムFCSの各部を制御するものである。例えば、コントローラECは、イグニッションスイッチから出力される起動信号IGを受信すると、燃料電池システムFCSの運転を開始する。その後、コントローラECは、アクセルセンサから出力されるアクセル開度信号ACCや、車速センサから出力される車速信号VCなどを基に、燃料電池システムFCS全体の要求電力を求める。燃料電池システムFCS全体の要求電力は、車両走行電力と補機電力との合計値である。 The controller EC (control unit) is a computer system including a CPU, a ROM, a RAM, and an input / output interface, and controls each unit of the fuel cell system FCS. For example, the controller EC starts the operation of the fuel cell system FCS when receiving the start signal IG output from the ignition switch. Thereafter, the controller EC obtains the required power of the entire fuel cell system FCS based on the accelerator opening signal ACC output from the accelerator sensor, the vehicle speed signal VC output from the vehicle speed sensor, and the like. The required power of the entire fuel cell system FCS is the total value of the vehicle travel power and the auxiliary power.

 ここで、補機電力には、車載補機類(加湿器、エアコンプレッサ、水素ポンプ、及び冷却水循環ポンプ等)で消費される電力、車両走行に必要な装置(変速機、車輪制御装置、操舵装置、及び懸架装置等)で消費される電力、乗員空間内に配設される装置(空調装置、照明器具、及びオーディオ等)で消費される電力などが含まれる。 Here, auxiliary electric power includes electric power consumed by in-vehicle auxiliary equipment (humidifier, air compressor, hydrogen pump, cooling water circulation pump, etc.), and equipment required for vehicle travel (transmission, wheel control device, steering) Power consumed by devices, suspension devices, etc.), power consumed by devices (air conditioners, lighting equipment, audio, etc.) disposed in the passenger space, and the like.

 そして、コントローラECは、燃料電池FCとバッテリES2とのそれぞれの出力電力の配分を決定する。コントローラECは、燃料電池FCの発電量が目標電力に一致するように、酸化ガス供給系ASS及び燃料ガス供給系FSSを制御するとともに、DC/DCコンバータES1を制御して、燃料電池FCの運転ポイント(出力端子電圧、出力電流)を制御する。更に、コントローラECは、アクセル開度に応じた目標トルクが得られるように、例えば、スイッチング指令として、U相、V相、及びW相の各交流電圧指令値をトラクションインバータES3に出力し、トラクションモータES4の出力トルク、及び回転数を制御する。更に、コントローラECは、冷却系CSを制御して燃料電池FCが適切な温度になるように制御する。 Then, the controller EC determines the distribution of the respective output powers of the fuel cell FC and the battery ES2. The controller EC controls the oxidizing gas supply system ASS and the fuel gas supply system FSS so that the power generation amount of the fuel cell FC matches the target power, and also controls the DC / DC converter ES1 to operate the fuel cell FC. Control points (output terminal voltage, output current). Further, the controller EC outputs, for example, each U-phase, V-phase, and W-phase AC voltage command value to the traction inverter ES3 as a switching command so as to obtain a target torque corresponding to the accelerator opening, Controls the output torque and rotation speed of the motor ES4. Further, the controller EC controls the cooling system CS so that the fuel cell FC has an appropriate temperature.

 本実施形態の燃料電池システムFCSは、上述した構成によって、燃料電池FCの理論起電圧を算出する電圧算出手段EC1と、燃料電池FCの開回路電圧を計測する電圧計測手段EC2と、電圧算出手段EC1が算出した理論起電圧と電圧計測手段EC2が計測した開回路電圧との差に基づいて、燃料電池FCを構成する単セルの膜厚を算出する膜厚算出手段EC3と、膜圧算出手段EC3が算出した膜厚が所定の限界膜厚以下の場合に報知する報知手段EC4とを供える燃料電池システムとして機能する。従って、コントローラECは、電圧算出手段EC1、電圧計測手段EC2、膜圧算出手段EC3、及び報知手段EC4として機能する。 The fuel cell system FCS of the present embodiment has the above-described configuration, voltage calculation means EC1 for calculating the theoretical electromotive voltage of the fuel cell FC, voltage measurement means EC2 for measuring the open circuit voltage of the fuel cell FC, and voltage calculation means. Based on the difference between the theoretical electromotive voltage calculated by EC1 and the open circuit voltage measured by the voltage measuring means EC2, the film thickness calculating means EC3 for calculating the film thickness of the single cell constituting the fuel cell FC, and the membrane pressure calculating means It functions as a fuel cell system provided with notifying means EC4 for notifying when the film thickness calculated by EC3 is not more than a predetermined limit film thickness. Therefore, the controller EC functions as voltage calculation means EC1, voltage measurement means EC2, membrane pressure calculation means EC3, and notification means EC4.

 図2は、本実施形態の燃料電池システムFCSにおいて、燃料電池FCを構成する単セルの膜厚を算出するフローを示したフローチャートである。ステップS01では、電圧計測手段EC2が、燃料電池FCの開回路電圧(OCV:Open Circuit Voltage)を計測する。尚、触媒中のPtの酸化を防ぐために、開回路電圧よりも低い電圧(OC回避電圧)で制限をかけた運転をしている場合には、この膜厚検知のため一時的にOC状態に移行させる。OC回避状態を一定時間以上継続している場合には、同一の条件を形成しやすくなり、そこからOC状態に移行させることでより膜厚検知の精度が向上する。 FIG. 2 is a flowchart showing a flow for calculating the film thickness of the single cells constituting the fuel cell FC in the fuel cell system FCS of the present embodiment. In step S01, the voltage measuring means EC2 measures the open circuit voltage (OCV: Open Circuit Voltage) of the fuel cell FC. In order to prevent the oxidation of Pt in the catalyst, when the operation is limited with a voltage lower than the open circuit voltage (OC avoidance voltage), the OC state is temporarily set to detect the film thickness. Transition. When the OC avoidance state continues for a certain time or more, the same condition is easily formed, and the film thickness detection accuracy is further improved by shifting to the OC state from there.

 ステップS01に続くステップS02では、膜厚算出手段EC3が燃料電池FCを構成する単セルの膜厚を算出する。具体的には、まず電圧算出手段EC1が燃料電池FCの理論起電圧を算出する。単セルの理論起電圧Eは式(4)によって求められる。
E=-Δgf/2F    (4)
式(4)において、Δgfはギブスの自由エネルギーであり、Fはファラデー定数である。100℃以下で動作する単セルの場合、この値は約1.2Vである。従って、燃料電池FCの理論起電圧は、この値とセル数によって求められる。そのため、理論起電圧は、電圧算出手段EC1が都度算出しても、燃料電池FCのスペックに基づいて予め定められていてもよい。
In step S02 following step S01, the film thickness calculation means EC3 calculates the film thickness of the single cells constituting the fuel cell FC. Specifically, first, the voltage calculation means EC1 calculates the theoretical electromotive voltage of the fuel cell FC. The theoretical electromotive voltage E of a single cell is obtained by equation (4).
E = -Δg f / 2F (4)
In equation (4), Δg f is Gibbs free energy and F is a Faraday constant. For a single cell operating below 100 ° C., this value is about 1.2V. Accordingly, the theoretical electromotive voltage of the fuel cell FC is obtained from this value and the number of cells. For this reason, the theoretical electromotive voltage may be calculated each time by the voltage calculation means EC1, or may be determined in advance based on the specifications of the fuel cell FC.

 続いて、理論起電圧と開回路電圧との差分であるΔVは式(5)によって表される。
ΔV=RT/2αF ×ln(icross/i)   (5)
尚、式(5)において、Rは気体定数、Fはファラデー定数、αは電荷移動係数である。電荷移動係数αは、燃料電池FCに用いられる触媒によって決定される係数である。また、iは出力電流、icrossは燃料ガスクロスリークによる内部電流である。温度等の条件が一定の場合、式(5)の右辺は、燃料ガスクロスリークによる内部電流icross以外は定数である。従って、ΔVによって内部電流icrossを求めることができる。ここで、
cross=Qcross×2F    (6)
cross=a×PH2×S/L   (7)
との関係がある。Qcrossはガスクロスリーク量であり、aは膜物性値であり、PH2は水素分圧であり、Sは単セルの膜面積、Lは単セルの膜厚である。膜厚算出手段EC3は、式(5)(6)(7)に基づいて、膜厚Lを求める。
Subsequently, ΔV, which is the difference between the theoretical electromotive voltage and the open circuit voltage, is expressed by Equation (5).
ΔV = RT / 2αF × ln (i cross / i) (5)
In equation (5), R is a gas constant, F is a Faraday constant, and α is a charge transfer coefficient. The charge transfer coefficient α is a coefficient determined by the catalyst used in the fuel cell FC. Further, i is an output current, and i cross is an internal current due to a fuel gas cross leak. When conditions such as temperature are constant, the right side of Equation (5) is a constant other than the internal current i cross due to fuel gas cross leak. Therefore, the internal current i cross can be obtained from ΔV. here,
i cross = Q cross × 2F (6)
Q cross = a × P H2 × S / L (7)
There is a relationship. Q cross is a gas cross leak amount, a is a film physical property value, P H2 is a hydrogen partial pressure, S is a film area of a single cell, and L is a film thickness of the single cell. The film thickness calculation means EC3 calculates the film thickness L based on the equations (5), (6), and (7).

 ステップS02に続くステップS03では、ステップS02で求めた膜厚Lが所定の限界膜厚L’を下回っているか判断する。この限界膜厚L’は、膜の強度等から予め定められるものである。算出した膜厚Lが限界膜厚L’を下回っている場合にはステップS04の処理に進み、算出した膜厚Lが限界膜厚L’を下回っていない場合には処理を終了する。 In step S03 subsequent to step S02, it is determined whether the film thickness L obtained in step S02 is less than a predetermined limit film thickness L '. This limit film thickness L ′ is determined in advance from the strength of the film. If the calculated film thickness L is less than the limit film thickness L ′, the process proceeds to step S <b> 04. If the calculated film thickness L is not less than the limit film thickness L ′, the process ends.

 ステップS04では、報知手段EC4が、アラートランプやスピーカー等を介してユーザに認識可能なように、燃料電池FCが劣化したことを報知する。 In step S04, the notification means EC4 notifies that the fuel cell FC has deteriorated so that it can be recognized by the user via an alert lamp or a speaker.

FCS:燃料電池システム
FC:燃料電池
ASS:酸化ガス供給系
AS1:フィルタ
AS2:エアコンプレッサ
AS3:酸化ガス流路
AS4:酸化オフガス流路
AS5:加湿器
A3:背圧調整弁
CS:冷却系
CS1:ラジエータ
CS2:冷却液ポンプ
CS3:冷却液往路
CS4:冷却液復路
FSS:燃料ガス供給系
FS1:燃料ガス供給源
FS2:インジェクタ
FS3:燃料ガス流路
FS4:循環流路
FS5:循環ポンプ
FS6:排気排水流路
H1:遮断弁
H2:レギュレータ
H3:遮断弁
H4:遮断弁
H5:排気排水弁
ES:電力系
ES1:DC/DCコンバータ
ES2:バッテリ
ES3:トラクションインバータ
ES4:トラクションモータ
ES5:補機類
EC:コントローラ
S1:電圧センサ
S2:電流センサ
S3:SOCセンサ
S4,S6:圧力センサ
S5:水温センサ
ACC:アクセル開度信号
IG:起動信号
VC:車速信号
FCS: Fuel cell system FC: Fuel cell ASS: Oxidizing gas supply system AS1: Filter AS2: Air compressor AS3: Oxidizing gas channel AS4: Oxidizing off gas channel AS5: Humidifier A3: Back pressure regulating valve CS: Cooling system CS1: Radiator CS2: Coolant pump CS3: Coolant forward path CS4: Coolant return path FSS: Fuel gas supply system FS1: Fuel gas supply source FS2: Injector FS3: Fuel gas channel FS4: Circulation channel FS5: Circulation pump FS6: Exhaust drainage Flow path H1: Shut-off valve H2: Regulator H3: Shut-off valve H4: Shut-off valve H5: Exhaust drain valve ES: Power system ES1: DC / DC converter ES2: Battery ES3: Traction inverter ES4: Traction motor ES5: Auxiliary equipment EC: Controller S1: Voltage sensor S2: Current sensor S3: SOC sensor S4 S6: a pressure sensor S5: the water temperature sensor ACC: accelerator opening signal IG: activation signal VC: vehicle speed signal

Claims (1)

 燃料電池に水素を含む燃料ガスと酸化ガスとを供給して発電させる燃料電池システムであって、
 前記燃料電池の開回路電圧を計測する電圧計測手段と、
 前記燃料電池の理論起電圧と前記電圧計測手段が計測した開回路電圧との差に基づいて、前記燃料電池を構成する単セルの膜厚を算出する膜厚算出手段と、
 前記膜厚算出手段が算出した膜厚が所定の限界膜厚以下の場合に報知する報知手段と、を備えることを特徴とする燃料電池システム。
A fuel cell system for generating power by supplying a fuel gas containing hydrogen and an oxidizing gas to a fuel cell,
Voltage measuring means for measuring an open circuit voltage of the fuel cell;
Based on the difference between the theoretical electromotive voltage of the fuel cell and the open circuit voltage measured by the voltage measuring means, the film thickness calculating means for calculating the film thickness of the single cells constituting the fuel cell;
A fuel cell system comprising: an informing means for informing when the film thickness calculated by the film thickness calculating means is equal to or less than a predetermined limit film thickness.
PCT/JP2009/066638 2009-09-25 2009-09-25 Fuel cell system Ceased WO2011036766A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2009/066638 WO2011036766A1 (en) 2009-09-25 2009-09-25 Fuel cell system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2009/066638 WO2011036766A1 (en) 2009-09-25 2009-09-25 Fuel cell system

Publications (1)

Publication Number Publication Date
WO2011036766A1 true WO2011036766A1 (en) 2011-03-31

Family

ID=43795537

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/066638 Ceased WO2011036766A1 (en) 2009-09-25 2009-09-25 Fuel cell system

Country Status (1)

Country Link
WO (1) WO2011036766A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015128000A (en) * 2013-12-27 2015-07-09 Toto株式会社 Solid oxide fuel cell

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003045466A (en) * 2001-07-26 2003-02-14 Honda Motor Co Ltd Gas leak detection method for fuel cell
JP2005063909A (en) * 2003-08-20 2005-03-10 Denso Corp Fuel cell system
JP2008293708A (en) * 2007-05-22 2008-12-04 Toyota Motor Corp Fuel cell system and fuel cell control method
JP2009016101A (en) * 2007-07-03 2009-01-22 Toyota Motor Corp Electrolyte membrane deterioration judgment method and electrolyte membrane deterioration judgment device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003045466A (en) * 2001-07-26 2003-02-14 Honda Motor Co Ltd Gas leak detection method for fuel cell
JP2005063909A (en) * 2003-08-20 2005-03-10 Denso Corp Fuel cell system
JP2008293708A (en) * 2007-05-22 2008-12-04 Toyota Motor Corp Fuel cell system and fuel cell control method
JP2009016101A (en) * 2007-07-03 2009-01-22 Toyota Motor Corp Electrolyte membrane deterioration judgment method and electrolyte membrane deterioration judgment device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015128000A (en) * 2013-12-27 2015-07-09 Toto株式会社 Solid oxide fuel cell

Similar Documents

Publication Publication Date Title
JP5273595B2 (en) Fuel cell system
JP5007665B2 (en) Fuel cell system
US8722266B2 (en) Fuel cell system
CN102244282B (en) fuel cell system
US8460835B2 (en) Fuel cell system
US9240602B2 (en) Fuel cell system
JP4789018B2 (en) Fuel cell system
CN105609836B (en) The method for controlling of operation of fuel cell system and fuel cell system
JP4492824B2 (en) Fuel cell system
JP5273249B2 (en) Fuel cell system
JP2010244937A (en) Fuel cell system
CN105609831A (en) Fuel cell system and operation control method of the same
JP5110410B2 (en) Fuel cell system
JP5570508B2 (en) Fuel cell system
JP5765260B2 (en) Fuel cell system
JP4337104B2 (en) Fuel cell system
JP2011070894A (en) Fuel cell system
JP2010262805A (en) Fuel cell system
JP5110411B2 (en) Fuel cell system
WO2011036766A1 (en) Fuel cell system
JP2012099237A (en) Fuel cell system
JP2013125589A (en) Cell voltage measuring apparatus

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09849797

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09849797

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP