Fuel cell activation method and activation device

Abstract

A method for activating a fuel cell stack is a method for activating a fuel cell stack, wherein the fuel cell stack comprises an electrolyte membrane containing a solid polymer, an anode electrode arranged on one surface of the electrolyte membrane, and a cathode electrode arranged on the other surface of the electrolyte membrane, wherein the method for activating the fuel cell stack comprises the following steps: a first energizing step, in which hydrogen is supplied to the anode electrode as an anode side gas, and air is supplied to the cathode electrode as a cathode side gas, thereby generating a potential difference between the two electrodes, and in this state, the two electrodes are electrically connected by an external electrical load and energized; and a second energizing step, in which hydrogen is supplied to the anode electrode as an anode side gas, and nitrogen is supplied to the cathode electrode as a cathode side gas, thereby generating a potential difference between the two electrodes, and in this state, the two electrodes are electrically connected by an external electrical load and energized.

Description

Technical Field

[0001] The present invention relates to a method and an activation device for a fuel cell, and more particularly to a method and an activation device for a fuel cell having an electrolyte layer containing a solid polymer, and an anode electrode and a cathode electrode provided on both sides of the electrolyte layer. Background Art

[0002] A fuel cell cell is formed by sandwiching an electrolyte membrane-electrode structure (so-called membrane electrode assembly (MEA)) with a pair of diaphragms, and the electrolyte membrane-electrode structure is formed by arranging an electrolyte layer containing a solid polymer between an anode electrode and a cathode electrode. In addition, a fuel cell stack is formed by stacking a plurality of such fuel cell cells, for example, using them as a power source for a vehicle.

[0003] As described above, the power generation performance of a fuel cell unit or a fuel cell stack (hereinafter, when there is no need to distinguish between a unit and a stack, they are also referred to as "fuel cells") will decrease immediately after being assembled. Therefore, after the fuel cell is assembled, various activation treatments (aging) are performed to improve its power generation performance.

[0004] For example, in the fuel cell activation method described in Patent Document 1, in an activation device that connects the anode electrode and the cathode electrode of the fuel cell via a switching element and a resistor element, a first step and a second step are alternately repeated, wherein the first step is to supply hydrogen to the anode electrode and air to the cathode electrode while the switching element is turned on, and the second step is to close the switching element and stop supplying air to the cathode electrode.

[0005] [Prior Technical Literature]

[0006] (Patent Document)

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-267455 Summary of the invention

[0008] [Problems to be solved by the invention]

[0009] In the activation method described in Patent Document 1, although the fuel cell can be activated using a simple activation device, when the air supply is stopped in the second step, the potential difference between the anode electrode and the cathode electrode becomes smaller due to the cross leakage of hydrogen from the anode electrode to the cathode electrode, so the aging effect is low and the activation may take a long time. In addition, when the second step is transferred to the first step and the air supply to the cathode electrode is started again, the hydrogen remaining in the cathode electrode directly reacts with the oxygen in the air newly supplied to the cathode electrode, which may cause the fuel cell to deteriorate due to heat.

[0010] An object of the present invention is to provide an activation method and an activation device that can suppress degradation of a fuel cell and activate the fuel cell in a short time.

[0011] [Technical means to solve the problem]

[0012] (1) The activation method of the fuel cell (e.g., the fuel cell monomer 2 and the fuel cell stack 1 described below) of the present invention is a method for activating a fuel cell, wherein the fuel cell comprises an electrolyte layer containing a solid polymer (e.g., the electrolyte membrane 24 described below), an anode electrode (e.g., the anode electrode 25 described below) disposed on one surface of the electrolyte layer, and a cathode electrode (e.g., the cathode electrode 26 described below) disposed on the other surface of the electrolyte layer, and the activation method of the fuel cell comprises the following steps: a first energizing step of supplying hydrogen gas as an anode side gas to the anode electrode and supplying a current to the anode electrode; The cathode electrode is supplied with an oxidant gas as a cathode side gas, thereby generating a potential difference between the anode electrode and the cathode electrode. In this state, the anode electrode and the cathode electrode are electrically connected to each other by an external electrical load (for example, the external electrical load 6 described later) and energized; and, in a second energization step, hydrogen gas is supplied to the anode electrode as an anode side gas, and an inert gas is supplied to the cathode electrode as a cathode side gas, thereby generating a potential difference between the anode electrode and the cathode electrode. In this state, the anode electrode and the cathode electrode are electrically connected to each other by the external electrical load and energized.

[0013] (2) At this time, it is preferable that the first energizing step and the second energizing step are repeated alternately a plurality of times.

[0014] (3) At this time, it is preferred that, in the aforementioned first power-on process, a mixed gas of an oxidant gas and an inert gas is supplied to the aforementioned cathode electrode as a cathode side gas, and when transferring from the aforementioned first power-on process to the aforementioned second power-on process, the supply of the inert gas continues and the supply of the oxidant gas is disconnected.

[0015] (4) At this time, it is preferable that during the second energizing step, after the potential difference between the anode electrode and the cathode electrode remains at or below a predetermined voltage for a predetermined time, the second energizing step is shifted to the first energizing step.

[0016] (5) The activation device (e.g., the activation device 3 described below) of the fuel cell (e.g., the fuel cell monomer 2 and the fuel cell stack 1 described below) of the present invention is a device for activating the fuel cell, wherein the fuel cell comprises an electrolyte layer containing a solid polymer (e.g., the electrolyte membrane 24 described below), an anode electrode (e.g., the anode electrode 25 described below) arranged on one surface of the electrolyte layer, and a cathode electrode (e.g., the cathode electrode 26 described below) arranged on the other surface of the aforementioned electrolyte layer, and the activation device of the fuel cell comprises: an external electrical load (e.g., the external electrical load 6 described below) for electrically connecting the aforementioned anode electrode and the aforementioned cathode electrode; a hydrogen supply source (e.g., the hydrogen gas supply source described below); a cathode side gas supply channel (for example, a cathode side gas supply channel 54 described below) for connecting the cathode electrode with the oxidant gas supply source and the inert gas supply source; and a control unit (for example, a control device 53 described below) for alternately connecting or disconnecting the supply of the oxidant gas from the oxidant gas supply source to the cathode electrode.

[0017] (6) At this time, it is preferred that the activation device further includes a voltage sensor (for example, the cell voltage sensor 7 described later), which detects the potential difference between the anode electrode and the cathode electrode, and when the supply of the oxidant gas is disconnected, the control unit turns on the supply of the oxidant gas after the potential difference drops to below a specified voltage for a specified period of time.

[0018] (Effects of the Invention)

[0019] (1) In the activation method of the present invention, the fuel cell is activated by performing a first energizing step and a second energizing step, wherein the first energizing step is to supply hydrogen gas to the anode electrode and an oxidant gas to the cathode electrode, thereby generating a potential difference between the two electrodes, and in this state, the two electrodes are electrically connected by an external electrical load to energize; and the second energizing step is to supply hydrogen gas to the anode electrode and an inert gas to the cathode electrode, thereby generating a potential difference between the two electrodes, and in this state, the two electrodes are electrically connected by an external electrical load to energize. Therefore, according to the activation method of the present invention, compared with the activation method described in Patent Document 1 in which air is intermittently supplied to the cathode electrode (hereinafter also referred to as "the conventional activation method"), the degradation of the fuel cell can be suppressed and the fuel cell can be activated in a short time.

[0020] Here, in the second energizing step, the difference in hydrogen concentration between the anode electrode supplying hydrogen and the cathode electrode supplying inert gas can be used to generate a potential difference between the two electrodes. In addition, by electrically connecting the two electrodes using an external electrical load in a state where a potential difference is generated, the two electrodes can be energized with a smaller current and a smaller supply amount of anode-side gas and cathode-side gas than in conventional power generation. In addition, in the second energizing step, the generated water generated by the electrode reaction caused by the hydrogen concentration difference can be supplied to the electrode catalyst or electrolyte layer contained in the anode electrode and the cathode electrode, so that the electrolyte layer can be made wet to generate good proton conductivity, or water can be supplied to the three-phase interface of the electrode catalyst, electrolyte layer and hydrogen or oxidant gas that becomes a reaction site when the fuel cell generates electricity, thereby efficiently activating the fuel cell.

[0021] Here, in the previous activation method, when the supply of oxidant gas to the cathode electrode is stopped, a hydrogen concentration difference will be generated between the two electrodes, so the fuel cell can also be activated. However, in the previous activation method, when the supply of oxidant gas to the cathode electrode is stopped, the hydrogen leaked from the anode electrode will be retained in the cathode electrode, and the potential difference between the two electrodes will decrease, so the activation effect gradually decreases. In addition, when the supply of oxidant gas is stopped and the oxidant gas is supplied again, the hydrogen remaining in the cathode electrode will directly react with the oxidant gas, so heat will be generated, and the fuel cell may deteriorate. In contrast, in the activation method of the present invention, by supplying an inert gas in the second power-on process, cross leakage from the anode electrode can be suppressed, so the hydrogen concentration difference can be maintained high, and thus a high activation effect can be maintained. In addition, in the activation method of the present invention, cross leakage can be suppressed in this way, so the direct reaction of the oxidant gas and hydrogen can be suppressed, and thus the degradation of the fuel cell can also be suppressed. Therefore, according to the activation method of the present invention, the fuel cell can be activated in a shorter time than the conventional activation method while suppressing the degradation of the fuel cell.

[0022] (2) In the activation method of the present invention, by repeating the first energizing step and the second energizing step alternately a plurality of times, the fuel cell can be activated more quickly than when both steps are performed once each.

[0023] (3) In the activation method of the present invention, in the first energizing step, a mixed gas of an oxidant gas and an inert gas is supplied to the cathode electrode as a cathode side gas, and when the first energizing step is transferred to the second energizing step, the inert gas is continuously supplied and the supply of the oxidant gas is cut off. Therefore, in the activation method of the present invention, the first energizing step and the second energizing step can be repeated alternately for a plurality of times only by repeatedly turning the supply of the oxidant gas on and off alternately, so that the fuel cell can be activated with a simple structure.

[0024] (4) When transferring from the first power-on process to the second power-on process, immediately after the transfer, the residual oxidant gas in the cathode electrode gradually decreases, so the potential difference between the anode electrode and the cathode electrode gradually decreases. Thereafter, if the residual oxidant gas in the cathode electrode disappears, the fuel cell becomes a hydrogen concentration difference cell, and the potential difference between the two electrodes is maintained at a specified voltage greater than 0. In contrast, in the activation method of the present invention, during the second power-on process, after the potential difference between the two electrodes is below the specified voltage for a specified time, the second power-on process is transferred to the first power-on process, so that the fuel cell can be made into a hydrogen concentration difference cell within a suitable time, so that the fuel cell can be efficiently activated.

[0025] (5) The activation device of the present invention comprises: an external electrical load electrically connecting the anode electrode and the cathode electrode; and a control unit alternately turning on or off the supply of the oxidant gas from the cathode side gas supply channel connecting the cathode electrode with the oxidant gas supply source and the inert gas supply source and the oxidant gas supply source to the cathode electrode. Thus, according to the activation device of the present invention, by using the control unit to alternately turn on or off the supply of the oxidant gas, the first energization step and the second energization step can be alternately repeated multiple times, so that as described above, the fuel cell can be activated efficiently while suppressing the degradation of the fuel cell.

[0026] (6) In the activation device of the present invention, when the supply of the oxidant gas is turned off, the control unit turns on the supply of the oxidant gas after the potential difference drops below the predetermined voltage for a predetermined time. Thus, the fuel cell can be turned into a hydrogen concentration difference cell within a suitable time, so the fuel cell can be activated efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a diagram showing the structure of a fuel cell stack and an activation device thereof according to one embodiment of the present invention.

[0028] Figure 2 It is a flowchart showing the specific process of the activation method according to one embodiment of the present invention.

[0029] Figure 3 This is a diagram showing an example of a change in the average voltage of cells of a fuel cell stack when the first energization step is performed after the second energization step. DETAILED DESCRIPTION

[0030] Hereinafter, the structure of the activation device 3 of the fuel cell stack 1 according to one embodiment of the present invention and the flow of an activation method for activating the fuel cell stack 1 using the activation device 3 will be described in detail with reference to the drawings.

[0031] Figure 1 1 is a diagram showing the structure of a fuel cell stack 1 and an activation device 3 thereof. The fuel cell stack 1 is formed by stacking a plurality of fuel cell monomers 2. Figure 1 Only a part of the plurality of fuel cell units 2 is shown in the figure. In addition, although the following description is made on the case where the fuel cell stack 1 is activated, the present invention is not limited thereto. The present invention may also activate each fuel cell unit 2 constituting the fuel cell stack 1.

[0032] The fuel cell unit 2 includes an electrolyte membrane-electrode assembly 21 (hereinafter referred to as "MEA 21") and a first diaphragm 22 and a second diaphragm 23 sandwiching the MEA 21. The MEA 21 includes an electrolyte membrane 24 which is an electrolyte layer of a solid polymer including a perfluorosulfonic acid film, for example, an anode electrode 25 provided on one surface of the electrolyte membrane 24, and a cathode electrode 26 provided on the other surface of the electrolyte membrane 25.

[0033] The anode electrode 25 is a porous body, and includes a first electrode catalyst layer 25a on one side facing the electrolyte membrane 24 and a first gas diffusion layer 25b stacked on the first electrode catalyst layer 25a. The cathode electrode 26 is a porous body, and includes a second electrode catalyst layer 26a on the other side facing the electrolyte membrane 24 and a second gas diffusion layer 26b stacked on the second electrode catalyst layer 26a.

[0034] The first electrode catalyst layer 25a and the second electrode catalyst layer 26a include catalyst particles (electrode catalysts) and ion-conductive polymer binders, wherein the catalyst particles are formed by supporting a catalyst metal such as platinum on a catalyst carrier made of carbon such as carbon black. In addition, the electrode catalyst may also be composed of only a catalyst metal such as platinum black without including a catalyst carrier.

[0035] When the electrode catalyst is composed of platinum, on the surface of the electrode catalyst, for example, 2Pt+H2O+1 / 2O2+e - →2Pt(OH - )、Pt(OH - )+H3O +→Pt+2H2O etc. Electrode reaction. This electrode reaction is promoted by supplying water to the surface of the electrode catalyst so that water exists at the three-phase interface. The three-phase interface refers to the interface between the electrode catalyst, the electrolyte membrane 24 and the hydrogen or oxidant gas, which becomes the reaction site when the fuel cell stack 1 actually generates electricity. In addition, the actual power generation of the fuel cell stack 1 refers to the time when the anode side gas containing hydrogen is supplied to the anode electrode 25, and the cathode side gas containing oxidant gas is supplied to the cathode electrode 26, and electricity is actually obtained from the fuel cell stack 1.

[0036] The first gas diffusion layer 25b and the second gas diffusion layer 26b are made of, for example, carbon paper or carbon cloth. The first gas diffusion layer 25b is arranged to face the first diaphragm 22, and the second gas diffusion layer 26b is arranged to face the second diaphragm 23. For example, a carbon diaphragm is used as the first diaphragm 22 and the second diaphragm 23, but a metal diaphragm may be used instead.

[0037] An anode side gas flow path 27 is formed on the surface of the first diaphragm 22 facing the first gas diffusion layer 25b, and the anode side gas flow path 27 is connected to an anode side gas inlet connecting hole (not shown) for supplying the anode side gas and an anode side gas outlet connecting hole (not shown) for discharging the anode side gas.

[0038] A cathode side gas flow path 28 is formed on the surface of the second membrane 23 facing the second gas diffusion layer 26b, and the cathode side gas flow path 28 is connected to a cathode side gas inlet connecting hole (not shown) for supplying cathode side gas and a cathode side gas outlet connecting hole (not shown) for discharging the cathode side gas.

[0039] In addition, in the fuel cell stack 1, a cooling medium flow path 29 is integrally formed between the opposing surfaces of the first diaphragm 22 and the second diaphragm 23 of each fuel cell monomer 2, and the cooling medium flow path 29 is connected to a cooling medium inlet connecting hole (not shown) for supplying a cooling medium and a cooling medium outlet connecting hole (not shown) for discharging the cooling medium.

[0040] The activation device 3 includes: an anode side gas supply device 4 for supplying anode side gas to the anode side gas flow path 27 of the fuel cell stack 1; a cathode side gas supply device 5 for supplying cathode side gas to the cathode side gas flow path 28 of the fuel cell stack 1; an external electrical load 6 for electrically connecting the anode electrode 25 and the cathode electrode 26 of the fuel cell stack 1; a single cell voltage sensor 7; and a temperature adjustment device 8 for adjusting the temperature of the fuel cell stack 1.

[0041] The external electrical load 6 electrically connects the anode electrode 25 and the cathode electrode 26 of the fuel cell stack 1, and conducts electricity between the two electrodes 25 and 26. When a potential difference is generated between the anode electrode 25 and the cathode electrode 26 by supplying anode-side gas from the anode-side gas supply device 4 to the anode electrode 25 and cathode-side gas from the cathode-side gas supply device 5 to the cathode electrode 26, the external electrical load 6 causes current to flow from the cathode electrode 26 to the anode electrode 25. In this external electrical load 6, the current conducted between the two electrodes 25 and 26 can be maintained at a predetermined magnitude.

[0042] The cell voltage sensor 7 detects the cell voltage generated between the anode electrode 25 and the cathode electrode 26 for each fuel cell 2, and sends a detection signal corresponding to the magnitude of the cell voltage to the control device 53 described later of the cathode side gas supply device 5. The average value of the cell voltage of each fuel cell 2, that is, the cell average voltage, is calculated by the control device 53 based on the detection signal from the cell voltage sensor 7.

[0043] The temperature adjustment device 8 adjusts the temperature of the fuel cell stack 1 by supplying a heat transfer medium adjusted to a predetermined temperature to the cooling medium flow path 29 of the fuel cell stack 1 .

[0044] The anode side gas supply device 4 supplies the anode side gas containing hydrogen to the anode side gas flow path 27. The anode side gas supply device 4 includes: a hydrogen supply source 41 for supplying hydrogen, a hydrogen supply passage 42 connecting the hydrogen supply source 41 and the anode side gas flow path 27, and an anode side humidifier 43 provided on the hydrogen supply passage 42. The hydrogen supply source 41 is composed of a hydrogen tank (not shown) storing hydrogen under high pressure and a flow rate regulating valve (not shown) regulating the flow rate of hydrogen supplied from the hydrogen tank to the hydrogen supply passage 42. The hydrogen supply passage 42 is a pipe connecting the hydrogen supply source 41 and the anode side gas flow path 27, and guides the hydrogen supplied from the hydrogen supply source 41 to the anode side gas flow path 27. The anode side humidifier 43 mixes the hydrogen supplied from the hydrogen supply source 41 with water vapor to adjust the dew point of the anode side gas. The anode gas supply device 4 supplies the anode gas adjusted to a predetermined dew point to the anode gas flow path 27 at a predetermined flow rate using the hydrogen gas supply source 41 , the hydrogen gas supply passage 42 , and the anode humidifier 43 .

[0045] The cathode side gas supply device 5 supplies cathode side gas including air as an oxidant gas or nitrogen as an inert gas to the cathode side gas flow path 28. The cathode side gas supply device 5 includes: an air pump 51 for supplying air, a nitrogen supply source 52 for supplying nitrogen gas, a control device 53 for controlling the air pump 51, a cathode side gas supply passage 54 for connecting the air pump 51 and the nitrogen supply source 52 to the cathode side gas flow path 28, and a cathode side humidifier 55 and a mixer 56 provided on the cathode side gas supply passage 54.

[0046] The cathode-side gas supply passage 54 includes a first flow path 54 a connecting the air pump 51 and the cathode-side gas flow path 28 , and a second flow path 54 b connecting the nitrogen gas supply source 52 and the first flow path 54 a .

[0047] The air pump 51 compresses the air according to the instruction from the control device 53, and supplies the compressed air to the cathode side gas flow path 28 via the first flow path 54a. The control device 53 adjusts the flow rate of the air supplied to the first flow path 54a by controlling the rotation speed of the air pump 51. The control device 53 can alternately turn on or off the supply of air from the air pump 51 to the cathode side gas flow path 28. In addition, in the present embodiment, the case where the supply of air from the air supply source to the cathode side gas flow path 28 is alternately turned on or off by controlling the rotation speed of the air pump 51 by the control device 53 is described, but the present invention is not limited to this. When a flow control valve is provided on the air flow path connecting the air supply source to the cathode side gas flow path 28, the supply of air from the air supply source to the cathode side gas flow path 28 can also be alternately turned on or off by controlling the opening of the flow control valve.

[0048] The nitrogen gas supply source 52 is composed of a nitrogen tank (not shown) storing nitrogen gas under high pressure, a flow rate regulating valve (not shown) regulating the flow rate of nitrogen gas supplied from the nitrogen tank to the second flow path 54b, and the like.

[0049] The cathode side humidifier 55 is provided on the first flow path 54a, mixes the air supplied from the air pump 51 with water vapor, and adjusts the dew point of the air flowing in the first flow path 54a. The mixer 56 is provided in the first flow path 54a at a position closer to the cathode side gas flow path 28 than the cathode side humidifier 55. The mixer 56 mixes the air supplied from the air pump 51 via the first flow path 54a and the nitrogen supplied from the nitrogen supply source 52 via the second flow path 54b, and supplies the mixture to the cathode side gas flow path 28. The cathode side gas supply device 5 uses these air pump 51, nitrogen supply source 52, control device 53, cathode side gas supply passage 54, cathode side humidifier 55 and mixer 56 to supply the cathode side gas adjusted to a predetermined dew point to the cathode side gas flow path 28 at a predetermined flow rate.

[0050] Next, a specific flow of an activation method for activating the fuel cell stack 1 using the activation device 3 described above will be described.

[0051] Figure 2 It is a flowchart showing the specific process of the activation method according to this embodiment.

[0052] First, in S1, the anode electrode 25 and the cathode electrode 26 of the fuel cell stack 1 are electrically connected by the external electrical load 6. Next, in S2, the fuel cell stack 1 is maintained at a specified temperature by supplying a heat transfer medium adjusted to a specified temperature to the cooling medium flow path 29 of the fuel cell stack 1 by the temperature adjustment device 8.

[0053] In S3, a first energizing step is performed within a predetermined time. In this first energizing step, anode gas is supplied from the anode gas supply device 4 to the anode gas flow path 27, and cathode gas is supplied from the cathode gas supply device 5 to the cathode gas flow path 28, so that a potential difference is generated between the anode electrode 25 and the cathode electrode 26, and electricity is supplied between these electrodes 25 and 26 by the external electrical load 6. In this first energizing step, the anode gas supply device 4 supplies the anode gas adjusted to a predetermined dew point by mixing hydrogen and water vapor to the anode gas flow path 27 at a predetermined flow rate. In addition, in this first energizing step, the cathode gas supply device 5 supplies a mixed gas of air adjusted to a predetermined dew point and a predetermined flow rate and nitrogen adjusted to a predetermined flow rate as the cathode gas to the cathode gas flow path 28. In the first energizing step, the anode gas supply device 4 and the cathode gas supply device 5 supply anode gas and cathode gas so that the pressure difference between the anode gas flow path 27 and the cathode gas flow path 28 is maintained at a predetermined value.

[0054] As described above, the first power-on process is the so-called conventional power generation aging process, that is, an anode side gas containing hydrogen is supplied to the anode electrode 25, and a cathode side gas containing oxidant gas is supplied to the cathode electrode 26, and conventional power generation is performed in the fuel cell stack 1, thereby promoting the activation of the fuel cell stack 1.

[0055] Next, in S4, a second energizing step is performed within a predetermined time. In this second energizing step, anode-side gas is supplied from the anode-side gas supply device 4 to the anode-side gas flow path 27, and cathode-side gas having a different composition from that in the first energizing step is supplied from the cathode-side gas supply device 5 to the cathode-side gas flow path 28, so that a potential difference is generated between the anode electrode 25 and the cathode electrode 26, and power is supplied between these electrodes 25 and 26 using the external electrical load 6.

[0056] Here, the flow rate ratio of air to nitrogen in the cathode side gas supplied to the cathode side gas flow path 28 (flow rate of air / flow rate of nitrogen) is set to be smaller in the second energization process than in the first energization process. As described later with reference to Example 4, the smaller the flow rate ratio of air to nitrogen in the cathode side gas in the second energization process is, the more efficient activation can be achieved. Therefore, the following will describe the case where the flow rate ratio of air to nitrogen in the cathode side gas supplied to the cathode side gas flow path 28 in the second energization process is set to 0 (that is, the case where the supply of air in the second energization process is disconnected), but the present invention is not limited to this.

[0057] In this second energizing step, the anode side gas supply device 4 supplies the anode side gas adjusted to a predetermined dew point by mixing hydrogen and water vapor to the anode side gas flow path 27 at a predetermined flow rate. In addition, the flow rate or dew point of the anode side gas in the second energizing step is preferably set to be equal to that in the first energizing step. Therefore, when the first energizing step and the second energizing step are alternately and repeatedly performed, it is preferred to continuously supply the anode side gas adjusted to a predetermined dew point to the anode side gas flow path 27 at a fixed flow rate.

[0058] In addition, in the second energizing process, the cathode side gas supply device 5 supplies nitrogen gas adjusted to a prescribed flow rate as the cathode side gas to the cathode side gas flow path 28. In addition, the flow rate of nitrogen gas in the second energizing process is preferably set to be equal to the flow rate of nitrogen gas in the first energizing process. Therefore, when the first energizing process and the second energizing process are alternately and repeatedly performed, it is preferred that nitrogen gas is continuously supplied from the nitrogen supply source 52 to the cathode side gas flow path 28 at a fixed flow rate. In addition, when transferring from the first energizing process to the second energizing process, it is preferred that the supply of air from the air pump 51 is disconnected by the control device 53 while nitrogen gas is continuously supplied at a fixed flow rate as described above. In addition, when transferring from the second energizing process to the first energizing process, it is preferred that the supply of air from the air pump 51 is turned on by the control device 53. In addition, in this second energizing process, similarly to the first energizing process, the anode side gas supply device 4 and the cathode side gas supply device 5 supply anode side gas and cathode side gas so that the pressure difference between the anode side gas flow path 27 and the cathode side gas flow path 28 is maintained at a specified value.

[0059] As described above, the second power-on process is the so-called hydrogen concentration difference cell aging process, that is, an anode side gas containing hydrogen is supplied to the anode electrode 25, and a cathode side gas containing an inert gas and not containing an oxidant gas is supplied to the cathode electrode 26, so that a hydrogen concentration difference is generated between the two electrodes 25, 26, and the fuel cell stack 1 is used as a hydrogen concentration difference cell, thereby promoting the activation of the fuel cell stack 1.

[0060] Next, in S5, it is determined whether the first energizing step and the second energizing step are repeatedly performed for a predetermined number of times. If the determination result of S5 is no, the process returns to S3 and the first energizing step and the second energizing step are performed again. If the determination result of S6 is yes, the process ends. Figure 2 In order to efficiently activate the fuel cell stack 1, it is preferred that the set number of times is set to an integer greater than 2, and the first energizing step and the second energizing step are repeated alternately a plurality of times.

[0061] Figure 3 1 is a diagram showing an example of a change in the average voltage of a cell of the fuel cell stack 1 when the first energization step is performed after the second energization step. More specifically, Figure 3 This is a diagram showing an example of changes in the average cell voltage when the fuel cell stack 1 is activated by Example 1 described later. Figure 3 , the following situation is shown, that is, the first power-on process is performed until time t0, then at time t0, the first power-on process is transferred to the second power-on process, then at time t2, the second power-on process is transferred to the first power-on process, and at time t3, the first power-on process is terminated. At this time, the control device 53 can also be changed in the following manner, that is, when the cell average voltage detected by the cell voltage sensor 7 becomes less than the predetermined judgment voltage during the second power-on process, it is reduced to a value smaller than the current consumption caused by the external electrical load in the first power-on process (more specifically, a value slightly larger than 0).

[0062] like Figure 3 As shown, when the first power-on process is transferred to the second power-on process at time t0, and the air supply to the fuel cell stack 1 is disconnected, the oxygen concentration in the cathode electrode 26 decreases, and the average voltage of the single cell gradually decreases. When the oxygen remaining in the cathode side gas flow path 28 is used up due to power generation around time t1, and the gas in the cathode side gas flow path 28 is replaced by nitrogen, the fuel cell stack 1 becomes a hydrogen concentration difference battery. Therefore, after time t1, the average voltage of the single cell remains higher than 0 [V]. When the second power-on process is transferred to the first power-on process at time t2, and the air supply to the fuel cell stack 1 is connected, the average voltage of the single cell is restored because normal power generation is performed in the fuel cell stack 1. At this time, the control device 53 can also be changed as follows, that is: when the single cell average voltage detected by the single cell voltage sensor 7 becomes lower than the specified judgment voltage during the second power-on process, the current consumption is increased in a manner that is reduced to a value smaller than the current consumption generated by the external electrical load in the first power-on process (more specifically, a value slightly larger than 0).

[0063] In the activation method of the present embodiment, the fuel cell stack 1 is activated by repeatedly performing the first power-on process and the second power-on process as described above alternately for multiple times. At this time, in order to efficiently activate the fuel cell stack 1 in a short time, it is preferred to ensure that the fuel cell stack 1 becomes a hydrogen concentration difference battery for more than a specified time during the execution of the second power-on process. Therefore, it is preferred that during the second power-on process, after the average cell voltage detected by the cell voltage sensor 7 is below the specified judgment voltage for a specified time, the control device 53 switches the supply of air to the cathode side gas flow path 28 from disconnection to connection, and transfers from the second power-on process to the first power-on process. Here, the judgment voltage is a threshold value set for the average cell voltage in order to determine that the fuel cell stack 1 becomes a hydrogen concentration difference battery, and it is set to a value slightly larger than 0.

[0064] According to the activation method and activation device 3 of this embodiment, the following effects are achieved.

[0065] (1) In the activation method of the present embodiment, the fuel cell stack 1 is activated by executing a first energizing step and a second energizing step. The first energizing step is to supply hydrogen to the anode electrode 25 and air to the cathode electrode 26, thereby generating a potential difference between the two electrodes 25 and 26. In this state, the two electrodes 25 and 26 are electrically connected by the external electrical load 6 to energize. The second energizing step is to supply hydrogen to the anode electrode 25 and nitrogen to the cathode electrode 26, thereby generating a potential difference between the two electrodes 25 and 26. In this state, the two electrodes are electrically connected by the external electrical load 6 to energize. Therefore, according to the activation method of the present embodiment, compared with the conventional activation method in which air is intermittently supplied to the cathode electrode 26, the deterioration of the fuel cell stack 1 can be suppressed and the fuel cell stack 1 can be activated in a short time.

[0066] Here, in the second energizing step, a potential difference can be generated between the anode electrode 25 supplying hydrogen and the cathode electrode 26 supplying nitrogen by using the hydrogen concentration difference between the two electrodes 25 and 26. In addition, by electrically connecting the two electrodes 25 and 26 by using the external electrical load 6 in a state where a potential difference is generated, the two electrodes 25 and 26 can be energized with a smaller current and a smaller supply amount of anode side gas and cathode side gas than in conventional power generation. In addition, in the second energizing step, the generated water generated by the electrode reaction caused by the hydrogen concentration difference can be supplied to the electrode catalyst or electrolyte layer contained in the anode electrode 25 and the cathode electrode 26, so that the electrolyte membrane 24 can be made wet to generate good proton conductivity, or water can be supplied to the three-phase interface of the electrode catalyst, the electrolyte membrane 24 and the hydrogen or air that becomes a reaction site when the fuel cell stack 1 generates electricity, thereby efficiently activating the fuel cell stack 1.

[0067] In addition, in the activation method of the present embodiment, by supplying nitrogen in the second energization step, cross leakage from the anode electrode 25 can be suppressed, so the hydrogen concentration difference can be maintained high, and thus a high activation effect can be maintained. In addition, in the activation method of the present embodiment, cross leakage can be suppressed in this way, so the direct reaction between air and hydrogen can be suppressed, and thus the degradation of the fuel cell stack 1 can also be suppressed. Therefore, according to the activation method of the present embodiment, while suppressing the degradation of the fuel cell stack 1, the fuel cell stack 1 can be activated in a shorter time compared to the previous activation method.

[0068] (2) In the activation method of the present embodiment, by repeating the first energizing step and the second energizing step alternately a plurality of times, the fuel cell can be activated more quickly than when both steps are performed once each.

[0069] (3) In the activation method of the present embodiment, in the first energizing step, a mixed gas of air and nitrogen is supplied to the cathode electrode 26 as the cathode side gas, and when the first energizing step is transferred to the second energizing step, the nitrogen supply is continued and the air supply is cut off. Therefore, in the activation method of the present embodiment, the first energizing step and the second energizing step can be repeated alternately for a plurality of times only by repeatedly turning the air supply on and off alternately, so the fuel cell stack 1 can be activated with a simple structure.

[0070] (4) In the activation method of the present embodiment, by transferring from the second power-on process to the first power-on process after the potential difference between the two electrodes 25 and 26 remains below a specified judgment voltage for a specified period of time during the second power-on process, the fuel cell stack 1 can be made into a hydrogen concentration difference cell within a suitable time, so that the fuel cell stack 1 can be efficiently activated.

[0071] (5) The activation device 3 of the present embodiment includes: an external electrical load 6 that electrically connects the anode electrode 25 and the cathode electrode 26; and a control device 53 that alternately turns on or off the supply of air from the cathode side gas supply passage 54 that connects the cathode electrode 26 to the air pump 51 and the nitrogen supply source 52 and the air pump 51 to the cathode electrode 26. Thus, according to the activation device 3 of the present embodiment, the first energization step and the second energization step can be alternately repeated multiple times by using the control device 53 to alternately turn on or off the supply of air, so that as described above, the fuel cell stack 1 can be activated efficiently while suppressing the degradation of the fuel cell stack 1.

[0072] (6) In the activation device 3 of the present embodiment, when the air supply is cut off, the control device 53 turns on the air supply after the state in which the average cell voltage detected by the cell voltage sensor 7 drops below the predetermined judgment voltage continues for a predetermined time. As a result, the fuel cell stack 1 can be made into a hydrogen concentration difference cell within a suitable time, so the fuel cell stack 1 can be activated efficiently.

[0073] An embodiment of the present invention has been described above, but the present invention is not limited thereto and the detailed structure can be appropriately changed within the scope of the gist of the present invention.

[0074] Example

[0075] Next, examples and comparative examples of the activation method are described. In the following examples and comparative examples, a fuel cell stack 1 assembled by stacking 10 fuel cell monomers 2 is used as the object for activation. In addition, the fuel cell monomer 2 uses a 100 [cm 2 ] of the MEA 21 monomer.

[0076] [Example 1]

[0077] In Example 1, the activation device 3 is connected to the above-mentioned 10-unit fuel cell stack 1, based on Figure 2The activation method alternately repeats the first power-on process and the second power-on process. At this time, the temperature of the fuel cell stack 1 is maintained at 70°C using the temperature adjustment device 8. In addition, in Example 1, by using the anode side gas supply device 4, hydrogen gas humidified in a manner to make the dew point 70°C is supplied to the anode side gas flow path 27 as the anode side gas. Here, the flow rate of hydrogen is set to 0.3 [NL / min]. In addition, in Example 1, by using the cathode side gas supply device 5, a mixed gas of air and nitrogen humidified in a manner to make the dew point 70°C is supplied to the cathode side gas flow path 28 as the cathode side gas. Here, the flow rate of air is set to 0.7 [NL / min], and the flow rate of nitrogen is set to 1.4 [NL / min]. In addition, in Example 1, while nitrogen gas is continuously supplied at the above-mentioned flow rate, the supply of air is switched from on to off or from off to on every one minute, thereby alternately performing the first power-on process and the second power-on process 30 times each at one minute intervals. That is, the activation time of Example 1 is 1 hour in total. In addition, in the first power-on process and the second power-on process, while supplying gas as described above, a current of 2 [A] continues to flow between the two electrodes 25 and 26. At this time, the anode side gas supply device 4 and the cathode side gas supply device 5 supply the anode side gas and the cathode side gas in such a way that the pressure difference between the anode side gas flow path 27 and the cathode side gas flow path 28 during the first power-on process and the second power-on process is maintained at a predetermined value.

[0078] [Comparative Example 1]

[0079] In Comparative Example 1, the activation device 3 was connected to the above-mentioned 10-unit fuel cell stack 1, and only Figure 2 The first energizing step in the activation method. At this time, the temperature of the fuel cell stack 1 is maintained at 70°C using the temperature regulating device 8. In Comparative Example 1, hydrogen gas humidified in a manner to a dew point of 70°C is supplied to the anode side gas flow path 27 as the anode side gas by using the anode side gas supply device 4. In addition, in Comparative Example 1, air humidified in a manner to a dew point of 70°C is supplied to the cathode side gas flow path 28 as the cathode side gas by using the cathode side gas supply device 5. Here, the flow rate of hydrogen gas is set to 20 [NL / min], the flow rate of air is set to 50 [NL / min], and a current of 150 [A] continues to flow between the two electrodes 25 and 26 for a total of 1 hour. As described above, the activation time in Comparative Example 1 is the same as that in Example 1, but the amount of hydrogen used and the current in Comparative Example 1 are larger than those in Example 1. In addition, the difference between Comparative Example 1 and Example 1 is that the second energizing step is not included.

[0080] [Comparative Example 2]

[0081] In Comparative Example 2, the activation device 3 was connected to the above-mentioned 10-cell fuel cell stack 1, and only Figure 2 The first power-on step in the activation method. At this time, the temperature of the fuel cell stack 1 is maintained at 70°C using the temperature adjustment device 8. In Comparative Example 2, hydrogen gas humidified in a manner to a dew point of 70°C is supplied to the anode side gas flow path 27 as the anode side gas by using the anode side gas supply device 4. In addition, in Comparative Example 2, air humidified in a manner to a dew point of 70°C is supplied to the cathode side gas flow path 28 as the cathode side gas by using the cathode side gas supply device 5. Here, the flow rate of hydrogen gas is set to 0.3 [NL / min], the flow rate of air is set to 0.7 [NL / min], and a current of 2 [A] continues to flow between the two electrodes 25 and 26 for a total of 1 hour. As described above, the activation time, the amount of hydrogen gas used, and the current in Comparative Example 2 and Example 1 are the same. In addition, the difference between Comparative Example 2 and Example 1 is that the second power-on step is not included.

[0082] [Comparative Example 3]

[0083] In Comparative Example 3, the activation device 3 is connected to the above-mentioned 10-cell fuel cell stack 1, and the activation method described in Japanese Patent Publication No. 2010-267455 is reproduced. At this time, the temperature of the fuel cell stack 1 is maintained at 70°C using the temperature adjustment device 8. In Comparative Example 3, hydrogen gas humidified in a manner to a dew point of 70°C is supplied to the anode side gas flow path 27 as the anode side gas by using the anode side gas supply device 4. Here, the flow rate of hydrogen gas is set to 0.3 [NL / min]. In addition, in Comparative Example 3, air humidified in a manner to a dew point of 70°C is supplied to the cathode side gas flow path 28 as the cathode side gas by using the cathode side gas supply device 5. In addition, in Comparative Example 3, the supply of air is switched from on to off or from off to on every one minute. Here, the flow rate of air during the period of switching on the supply of air is set to 0.7 [NL / min]. In Comparative Example 3, the process of turning on the air supply and the process of turning off the air supply were performed alternately at intervals of one minute 30 times each. That is, the activation time of Comparative Example 3 was 1 hour in total. In Comparative Example 3, while supplying the gas as described above, a current of 2 [A] continued to flow between the two electrodes 25 and 26. As described above, the activation time, the amount of hydrogen used, and the current in Comparative Example 3 and Example 1 were the same. In addition, the difference between Comparative Example 3 and Example 1 is that nitrogen was not supplied during the period of turning off the air supply.

[0084] Next, the performance of the fuel cell stack activated by the activation method of the above-mentioned embodiment 1 and comparative examples 1 to 3 is described with reference to the following Table 1. Table 1 is a diagram comparing the magnitude of voltage when a current of 150 [A] is drawn from the fuel cell stack activated by the activation method of the embodiment 1 and comparative examples 1 to 3. In addition, in the following Table 1, the voltage of the fuel cell stack activated by the activation method of comparative example 2 is set to "1".

[0085] [Table 1]

[0086] Voltage@150[A] Example 1 1.64 Comparative Example 1 1.49 Comparative Example 2 1.00 Comparative Example 3 1.10

[0087] As described in Table 1 above, the voltage of the activated fuel cell stack increases in the order of Comparative Example 2, Comparative Example 3, Comparative Example 1, and Example 1. As described above, in Example 1 and Comparative Examples 1 to 3, the activation time is the same. Therefore, it can be said that the activation method of Example 1 can efficiently activate the fuel cell stack in a shorter time than the activation methods of Comparative Examples 1 to 3. In addition, as described above, when comparing Comparative Example 1 with Example 1, the amount of hydrogen used and the current of Comparative Example 1 are greater. Therefore, it can be said that according to the activation method of Example 1, the fuel cell stack can be efficiently activated with less cost than Comparative Examples 1 to 3.

[0088] In addition, as described above, when comparing Comparative Example 3 with Example 1, the difference between the activation method of Comparative Example 3 and the activation method of Example 1 is that nitrogen is not supplied during the period when the air supply is disconnected. Therefore, in the activation method of Comparative Example 3, hydrogen cross-leakages from the anode electrode to the cathode electrode during the period when the air supply is disconnected, and the potential difference between the two electrodes decreases. Therefore, according to the activation method of Example 1, the fuel cell stack can be activated efficiently in a shorter time than the activation method of Comparative Example 3. In addition, in the activation method of Comparative Example 3, when the air supply is switched from disconnected to connected, the hydrogen remaining in the cathode electrode directly reacts with the oxygen in the newly supplied air, which may cause the fuel cell stack to deteriorate due to heat. In contrast, in the activation method of Example 1, nitrogen is continuously supplied during the period when the air supply is disconnected, so the cross leakage of hydrogen is less, thereby suppressing the degradation of the fuel cell stack.

[0089] [Example 2]

[0090] In Example 2, the activation time is set to 1 hour, the same as in Example 1, and the number of times the first energizing step and the second energizing step are alternately repeated (number of repetitions) and the time (interval time) for performing the first energizing step or the second energizing step are changed according to Table 2 below. In Example 2-1, the number of repetitions is set to 2 [times] and the interval time is set to 15 [minutes], in Example 2-2, the number of repetitions is set to 5 [times] and the interval time is set to 5 [minutes], in Example 2-3, the number of repetitions is set to 10 [times] and the interval time is set to 3 [minutes], and in Example 2-4, the number of repetitions is set to 60 [times] and the interval time is set to 0.5 [minutes].

[0091] [Table 2]

[0092]

[0093] As shown in Table 2 above, the voltage of the activated fuel cell stack increases in the order of Comparative Example 3, Example 2-1, Example 2-2, Example 2-4, Example 2-3, and Example 1. That is, for the 10-unit fuel cell stack 1 used this time, it can be said that the fuel cell stack can be activated most efficiently by setting the number of repetitions to 30. Based on the above, the activation method of the present invention can efficiently activate the fuel cell stack in a short time by adjusting the number of repetitions according to the specifications of the fuel cell stack to be activated.

[0094] [Example 3]

[0095] In Example 3, the time (interval time) for performing the first power-on process or the second power-on process is set to 1 [minute], the same as in Example 1, and the time for performing activation and the number of times (number of repetitions) for alternately repeating the first power-on process and the second power-on process are changed according to the following Table 3. In Example 3-1, the number of repetitions is set to 10 [times] and the activation time is set to 1 / 3 [hour]. In Example 3-2, the number of repetitions is set to 20 [times] and the activation time is set to 2 / 3 [hour]. In Example 3-3, the number of repetitions is set to 60 [times] and the activation time is set to 2 [hours]. In Example 3-4, the number of repetitions is set to 90 [times] and the activation time is set to 3 [hours].

[0096] [Table 3]

[0097]

[0098] As shown in Table 3 above, the voltage of the activated fuel cell stack increases in the order of Example 3-1, Example 3-2, Example 1, Example 3-3, and Example 3-4. That is, it can be said that the activation method of the present invention can activate the fuel cell stack more as the number of repetitions increases and the activation time is prolonged, but its efficiency decreases as the number of repetitions increases and the activation time is prolonged.

[0099] [Example 4]

[0100] In Example 4, the activation time, the number of repetitions and the interval time are set to be the same as those in Example 1, and the flow rate of air in the second power-on process is changed according to the following Table 4. In Example 4-1, the flow rate of air in the second power-on process is set to 0.20 [NL / min], in Example 4-2, the flow rate of air in the second power-on process is set to 0.37 [NL / min], in Example 4-3, the flow rate of air in the second power-on process is set to 0.40 [NL / min], and in Example 4-4, the flow rate of air in the second power-on process is set to 0.50 [NL / min]. In addition, the flow rates of gases such as hydrogen and nitrogen other than the flow rate of air in the second power-on process are the same as those in Example 1. In addition, the stoichiometric ratio of air in the second power-on process is 0.6 in Example 4-1, 1.12 in Example 4-2, 1.21 in Example 4-3, and 1.51 in Example 4-4. Here, the stoichiometric ratio of air in the second power-on process refers to the ratio of the air flow rate in the second power-on process to the theoretical air flow rate required for normal power generation in the fuel cell stack 1 while supplying hydrogen to the anode side gas flow path 27 (the air flow rate in the second power-on process / theoretical air flow rate).

[0101] [Table 4]

[0102]

[0103]

[0104] As shown in Table 4 above, the voltage of the activated fuel cell stack increases in the order of Example 4-4, Example 4-3, Example 4-2, Example 4-1, and Example 1. That is, it can be said that in the activation method of the present invention, the more the flow rate of air in the second energization process is reduced, in other words, the more the flow rate ratio of air to nitrogen (flow rate of air / flow rate of nitrogen) in the cathode side gas supplied to the cathode side gas flow path 28 in the second energization process is reduced, the more efficient activation can be performed in a short time. In particular, according to the results of Table 4 above, it can be found that there is a large difference in the effect of activation between Example 4-2 and Example 4-3. Therefore, it can be said that it is preferred to make the flow rate of air supplied to the cathode side gas flow path 28 in the second energization process less than the flow rate of air supplied to the cathode side gas flow path 28 in the first energization process, and set the stoichiometric ratio to less than 1.12.

[0105] [Example 5]

[0106] In Example 5, the activation time, number of repetitions, interval time and flow rates of various gases are set to be the same as those in Example 1, and the combination of the temperature of the fuel cell stack (stack temperature), the dew point of the anode side gas (anode dew point) and the dew point of the cathode side gas (cathode dew point) is changed according to the following Table 5. In Example 5-1, the stack temperature is set to 50 [°C], the anode dew point is set to 50 [°C], and the cathode dew point is set to 50 [°C]. In Example 5-2, the stack temperature is set to 50 [°C], the anode dew point is set to 70 [°C], and the cathode dew point is set to 70 [°C]. In Example 5-3, the stack temperature is set to 70 [°C], the anode dew point is set to 60 [°C], and the cathode dew point is set to 70 [°C]. In Example 5-4, the stack temperature is set to 70 [°C], the anode dew point is set to 60 [°C], and the cathode dew point is set to 70 [°C]. The dew point is set to 70 [℃] and the cathode dew point is set to 60 [℃]. In Example 5-5, the stack temperature is set to 70 [℃], the anode dew point is set to 80 [℃], and the cathode dew point is set to 80 [℃]. In Example 5-6, the stack temperature is set to 80 [℃], the anode dew point is set to 80 [℃], and the cathode dew point is set to 80 [℃]. In Example 5-7, the stack temperature is set to 80 [℃], the anode dew point is set to 70 [℃], and the cathode dew point is set to 70 [℃].

[0107] [Table 5]

[0108]

[0109]

[0110] As recorded in Table 5 above, the voltage of the activated fuel cell stack increases in the order of Example 5-1, Example 5-2, Example 5-7, Example 5-3, Example 1, Example 5-4, Example 5-6 and Example 5-5. In particular, according to the results of Table 5 above, it can be found that there is a large difference in the activation effect between Example 5-1 and Example 5-2. Therefore, it can be said that it is preferred to make the dew point of the anode side gas higher than 50 [℃] and the dew point of the cathode side gas higher than 50 [℃]. According to the above content, the activation method of the present invention can efficiently activate the fuel cell stack in a short time by adjusting the stack temperature, anode dew point and cathode dew point according to the specifications of the fuel cell stack to be activated.

[0111] Reference numerals

[0112] 1 Fuel cell stack (fuel cell)

[0113] 2 Fuel cell monomer (fuel cell)

[0114] 24. Electrolyte membrane (electrolyte layer)

[0115] 25 Anode electrode

[0116] 26 Cathode electrode

[0117] 3 Activation device

[0118] 4 Anode side gas supply device

[0119] 41 Hydrogen supply source

[0120] 42 Hydrogen supply channel (anode side gas supply channel)

[0121] 5 Cathode side gas supply device

[0122] 51 Air pump (oxidant gas supply source)

[0123] 52 Nitrogen supply source (inert gas supply source)

[0124] 53 Control device (switching unit)

[0125] 54 Cathode side gas supply channel (Cathode side gas supply channel)

[0126] 6 External electrical load (External electrical load)

[0127] 7 Single voltage sensor (voltage sensor)

Claims

1. A method for activating a fuel cell, the fuel cell comprising an electrolyte layer containing a solid polymer, an anode electrode provided on one surface of the electrolyte layer, and a cathode electrode provided on the other surface of the electrolyte layer, The fuel cell activation method comprises the following steps: A first energizing step is to supply hydrogen gas as an anode side gas to the anode electrode and to supply an oxidant gas as a cathode side gas to the cathode electrode, thereby generating a potential difference between the anode electrode and the cathode electrode, and in this state, electrically connecting the anode electrode and the cathode electrode by an external electrical load to energize; and, In the second energizing step, hydrogen gas is supplied to the anode electrode as an anode side gas, and an inert gas is supplied to the cathode electrode as a cathode side gas, thereby generating a potential difference between the anode electrode and the cathode electrode. In this state, the anode electrode and the cathode electrode are electrically connected by the external electrical load to energize. During the second energizing step, after the potential difference between the anode electrode and the cathode electrode remains greater than 0 and equal to or less than a predetermined voltage for a predetermined time, the second energizing step is shifted to the first energizing step.

2. The method for activating a fuel cell according to claim 1, wherein: The first energizing step and the second energizing step are repeated alternately multiple times.

3. The method for activating a fuel cell according to claim 1 or 2, wherein: In the first energizing step, a mixed gas of an oxidant gas and an inert gas is supplied to the cathode electrode as a cathode side gas. When the process shifts from the first energization step to the second energization step, the supply of the inert gas continues, and the supply of the oxidizing gas is shut off.

4. An activation device for a fuel cell, the fuel cell comprising an electrolyte layer containing a solid polymer, an anode electrode provided on one surface of the electrolyte layer, and a cathode electrode provided on the other surface of the electrolyte layer, The fuel cell activation device comprises: an external electrical load, used to electrically connect the anode electrode to the cathode electrode; A hydrogen supply source, used for supplying hydrogen; an anode-side gas supply channel for connecting the anode electrode to the hydrogen supply source; an oxidant gas supply source for supplying oxidant gas; An inert gas supply source, used for supplying an inert gas; a cathode-side gas supply channel for connecting the cathode electrode to the oxidant gas supply source and the inert gas supply source; a control unit for alternately turning on or off the supply of the oxidant gas from the oxidant gas supply source to the cathode electrode; and a voltage sensor for detecting a potential difference between the anode electrode and the cathode electrode, When the supply of the oxidizing gas is turned off, the control unit turns on the supply of the oxidizing gas after the potential difference continues to be lower than 0 and lower than a predetermined voltage for a predetermined time.

Images