Method for activating a polymer electrolyte fuel cell

Abstract

To provide a method capable of activating a solid polymer fuel cell in a shorter time.SOLUTION: Disclosed is an activation method for a solid polymer fuel cell having an electrode membrane structure in which an anode electrode and a cathode electrode are disposed oppositely via a solid polymer membrane. The activation method for the solid polymer fuel cell includes: pressurizing and supplying a humidified hydrogen containing gas, that is humidified, to the anode electrode while heating the solid polymer fuel cell within a predetermined range (preferably within a range from 100°C or higher to 300°C or lower, more preferably within a range from 100°C or higher to 200°C or lower and further preferably within a range from 100°C or higher to 150°C or lower); and pressurizing and supplying a humidified oxygen containing gas or a humidified nitrogen containing inert gas, that is humidified, to the cathode electrode.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a method for activating a solid polymer fuel cell. 【Background Art】 【0002】 In recent years, research and development on fuel cells that contribute to energy efficiency have been conducted in order to enable more people to access affordable, reliable, sustainable, and advanced energy. As a fuel cell, a solid polymer fuel cell having an electrode membrane structure (MEA) in which an anode electrode and a cathode electrode are disposed opposite each other through a solid polymer membrane is known. This solid polymer fuel cell generally has low power generation performance immediately after production. Therefore, it is common to perform an activation treatment (aging) to activate the solid polymer fuel cell before shipment. As a method for activating a solid polymer fuel cell, while supplying a humidified hydrogen-containing gas to the anode electrode and a humidified oxygen-containing gas or a humidified nitrogen-containing inert gas to the cathode electrode, the solid polymer fuel cell is heated, or a voltage that varies within a predetermined range is applied between the cathode electrode and the anode electrode (see, for example, Citation Document 1). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 International Publication No. 2011 / 125840 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 By the way, in the technology related to solid polymer fuel cells, shortening the activation treatment time for improving productivity is one of the problems. Therefore, further improvement of the conventional activation method is desired. 【0005】 This invention has been made in view of the above circumstances, and aims to provide a method for activating a polymer electrolyte fuel cell in a shorter time. [Means for solving the problem] 【0006】 The inventors have discovered that the above problems can be solved by supplying a predetermined humidifying gas under pressure to the anode and cathode electrodes of a polymer electrolyte fuel cell while heating the fuel cell during the activation process, or by heating the polymer electrolyte fuel cell and then supplying a predetermined humidifying gas to the anode and cathode electrodes while the heating is stopped, and have completed the present invention. Accordingly, the present invention provides the following. 【0007】 (1) A method for activating a polymer electrolyte fuel cell having an electrode membrane structure in which an anode electrode and a cathode electrode are arranged opposite each other via a solid polymer membrane, wherein the polymer electrolyte fuel cell is heated at a set temperature set within a predetermined range, while a humidified hydrogen-containing gas is supplied to the anode electrode under pressure, and a humidified oxygen-containing gas or a humidified nitrogen-containing inert gas is supplied to the cathode electrode under pressure. 【0008】 According to the method for activating a polymer electrolyte fuel cell described in (1), a humidified hydrogen-containing gas is supplied to the anode electrode and a humidified oxygen-containing gas or humidified nitrogen-containing inert gas is supplied to the cathode electrode while the polymer electrolyte fuel cell is being heated. This facilitates the activation of the catalysts in the side catalyst layers of the anode and cathode. Furthermore, the water vapor contained in the humidified gas facilitates the wetting of the catalyst layers and polymer electrolyte membranes of the anode and cathode electrodes. In addition, since a pressurized humidified hydrogen-containing gas is supplied to the anode electrode and a pressurized humidified oxygen-containing gas or humidified nitrogen-containing inert gas is supplied to the cathode electrode, water vapor can be efficiently supplied to the anode and cathode electrodes. Therefore, the polymer electrolyte fuel cell can be activated in a shorter time. 【0009】 (2) The method for activating a polymer electrolyte fuel cell according to (1), wherein the humidified hydrogen-containing gas is heated to the set temperature, and the humidified oxygen-containing gas or humidified nitrogen-containing inert gas is heated to the set temperature. 【0010】 According to the method for activating a polymer electrolyte fuel cell described in (2), the decrease in humidity due to heating of the humidified hydrogen-containing gas supplied to the anode and the decrease in humidity due to heating of the humidified oxygen-containing gas supplied to the cathode are suppressed, so that water vapor can be supplied to the anode and cathode more efficiently. 【0011】 (3) The method for activating a polymer electrolyte fuel cell according to (1) or (2), further comprising heating the polymer electrolyte fuel cell and applying a voltage between the cathode electrode and the anode electrode, with the cathode electrode set to positive, which fluctuates within a predetermined range. 【0012】 According to the method for activating a polymer electrolyte fuel cell described in (3), applying a voltage between the cathode and anode electrodes facilitates the activation of the polymer electrolyte fuel cell. 【0013】 (4) A method for activating a polymer electrolyte fuel cell having an electrode membrane structure in which an anode electrode and a cathode electrode are arranged opposite each other via a solid polymer membrane, the method comprising: heating the polymer electrolyte fuel cell to a set temperature set within a predetermined range; then, with the heating stopped, supplying humidified hydrogen-containing gas to the anode electrode and supplying humidified oxygen-containing gas or humidified nitrogen-containing inert gas to the cathode electrode. 【0014】 According to the method for activating a polymer electrolyte fuel cell in (4), after activating the polymer electrolyte fuel cell by heating, heating is stopped and then a humidified hydrogen-containing gas is supplied to the anode electrode and a humidified oxygen-containing gas or a humidified nitrogen-containing inert gas is supplied to the cathode electrode. Therefore, water vapor can be efficiently supplied to the anode electrode and the cathode electrode without pressurizing the humidified hydrogen-containing gas, humidified oxygen-containing gas or humidified nitrogen-containing inert gas. 【Advantages of the Invention】 【0015】 According to the present invention, it becomes possible to provide a method for activating a solid polymer fuel cell in a shorter time. 【Brief Description of the Drawings】 【0016】 [Figure 1] FIG. 1 is a block diagram showing an activation treatment apparatus that can be used in a method for activating a solid polymer fuel cell according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a state of an example during activation of a solid polymer fuel cell by a method for activating a solid polymer fuel cell according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing a state of another example during activation of a solid polymer fuel cell by a method for activating a solid polymer fuel cell according to an embodiment of the present invention. 【Embodiments for Carrying Out the Invention】 【0017】 Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments and can be appropriately modified and implemented without departing from the spirit of the present invention. 【0018】 FIG. 1 is a block diagram showing an activation treatment apparatus that can be used in a method for activating a solid polymer fuel cell according to an embodiment of the present invention. 【0019】 The activation treatment apparatus 100 shown in FIG. 1 is an apparatus for activating the fuel cell stack 10s. The fuel cell stack 10s stores a plurality of solid polymer fuel cells 10. 【0020】 The activation treatment apparatus 100 includes an anode-side gas supply device 20, a cathode-side gas supply device 30, a power source 40, a heating device 50, and a voltmeter 60. 【0021】 The anode-side gas supply device 20 includes a humidifier 21. The anode-side gas supply device 20 is a device for pressurizing and supplying a humidified hydrogen-containing gas to the anode of the solid polymer fuel cell 10. The cathode-side gas supply device 30 includes a humidifier 31. The cathode-side gas supply device 30 is a device for pressurizing and supplying a humidified oxygen-containing gas or a humidified nitrogen-containing inert gas to the cathode of the solid polymer fuel cell 10. 【0022】 The power source 40 is connected to the fuel cell stack 10s and is a device for applying a voltage between the cathode and the anode of the solid polymer fuel cell 10 during the activation process. The heating device 50 is a device for heating the solid polymer fuel cell 10 to a predetermined temperature. The voltmeter 60 is a device for measuring the output voltage of the solid polymer fuel cell 10. The state of the fuel cell stack 10s can be monitored by the output voltage measured by the voltmeter 60. 【0023】 Next, a method for activating a solid polymer fuel cell according to an embodiment of the present invention using an activation device 100 will be described. 【0024】 [First Embodiment] In the first embodiment of the method for activating a polymer electrolyte fuel cell, the fuel cell stack 10s is heated to a set temperature using a heating device 50. The set temperature is preferably set within the range of 100°C to 300°C, more preferably 100°C to 200°C, and even more preferably 100°C to 150°C. In this embodiment, while heating the fuel cell stack 10s, humidified hydrogen-containing gas generated by the anode-side gas supply device 20 is supplied under pressure to the anode of the polymer electrolyte fuel cell cell 10, and humidified oxygen-containing gas or humidified nitrogen-containing inert gas generated by the cathode-side gas supply device 30 is supplied under pressure to the anode of the polymer electrolyte fuel cell cell 10. As the hydrogen-containing gas, for example, a hydrogen-containing gas or a hydrogen-nitrogen mixed gas can be used. As the oxygen-containing gas, for example, air, pure oxygen gas, or an oxygen-nitrogen mixed gas can be used. As the humidified nitrogen-containing inert gas, an inert gas containing nitrogen but not air or pure oxygen gas can be used. 【0025】 When a humidifying gas—a humidifying hydrogen-containing gas, a humidifying oxygen-containing gas, or a humidifying nitrogen-containing inert gas—is supplied to the polymer electrolyte fuel cell cell 10 while the fuel cell stack 10s is being heated, the relative humidity of each humidifying gas may decrease, potentially hindering the activation of the anode electrode by water vapor. Therefore, in this embodiment, each humidifying gas is pressurized before being supplied to the polymer electrolyte fuel cell cell 10. The pressure of each humidifying gas is preferably in the range of 0 kPaG to 8952 kPaG, more preferably 0 kPaG to 1464 kPaG, and even more preferably 0 kPaG to 375 kPaG. Furthermore, in order to suppress the decrease in humidity due to the temperature rise of each humidifying gas when supplied to the polymer electrolyte fuel cell cell 10, each humidifying gas may be heated to a set temperature set by the heating of the fuel cell stack 10s, and the dew point of each humidifying gas may be adjusted to that set temperature. 【0026】 In this embodiment, while heating the fuel cell stack 10s, a voltage fluctuating within a predetermined range may be applied between the cathode and anode electrodes of the polymer electrolyte fuel cell cell 10, with the cathode electrode set to positive. The voltage application conditions may be, for example, conditions in which a potential scan is performed within a potential range set to 0.01V or more and 1.0V or less, with a period set to 10 seconds or more and 60 seconds or less. Applying a voltage makes it easier for the activation of the polymer electrolyte fuel cell cell 10 to proceed. The voltage may be applied continuously or intermittently. 【0027】 In this embodiment, the supply of humidified hydrogen-containing gas to the anode and the supply of humidified oxygen-containing gas or humidified nitrogen-containing inert gas to the cathode may be performed continuously or intermittently. Furthermore, the gas supplied to the cathode may be intermittently switched between humidified oxygen-containing gas and humidified nitrogen-containing inert gas. 【0028】 Figure 2 is a schematic diagram showing an example of the state during activation of a polymer electrolyte fuel cell according to an activation method for a polymer electrolyte fuel cell according to one embodiment of the present invention. Figure 2 shows an example where humidified oxygen-containing gas is supplied to the cathode electrode. 【0029】 As shown in Figure 2, the polymer electrolyte fuel cell cell 10 has an electrode membrane structure in which an anode electrode 12 and a cathode electrode 15 are arranged opposite each other via a polymer electrolyte membrane 11. The anode electrode 12 comprises an anode-side catalyst layer 13 in contact with the polymer electrolyte membrane 11 and an anode-side gas diffusion layer 14 located on the opposite side of the anode-side catalyst layer 13 from the polymer electrolyte membrane 11 side. The cathode electrode 15 comprises a cathode-side catalyst layer 16 in contact with the polymer electrolyte membrane 11 and a cathode-side gas diffusion layer 17 located on the opposite side of the cathode-side catalyst layer 16 from the polymer electrolyte membrane 11 side. The voltage applied between the anode electrode 12 and the cathode electrode 15 during the activation process is adjusted by a voltage regulator 41. The voltage regulator 41 is connected to a power supply 40. 【0030】 The humidified hydrogen-containing gas supplied to the anode electrode 12 moves through the anode-side gas diffusion layer 14 to the anode-side catalyst layer 13. In the anode-side catalyst layer 13, the hydrogen (H2) of the humidified hydrogen-containing gas reduces and removes deposits on the surface of the catalyst (Pt), activating the catalyst and producing protons (H2). + ) and the electrons generated at this time move to the cathode side through the external circuit. Protons move to the cathode-side catalyst layer 16 by the hydrogen pump. The protons that have moved to the cathode-side catalyst layer 16 receive electrons and also combine with oxygen to produce water. The water vapor (H2O) of the humidified hydrogen-containing gas wets the anode-side catalyst layer 13. As the anode-side catalyst layer 13 is wetted, a proton path is formed in the anode-side catalyst layer 13, making it easier for protons to move to the solid polymer membrane 11. Furthermore, the water (H2O) of the humidified hydrogen-containing gas moves to the solid polymer membrane 11, wetting the solid polymer membrane 11. 【0031】 The humidified oxygen-containing gas supplied to the cathode electrode 15 moves through the cathode-side gas diffusion layer 17 to the cathode-side catalyst layer 16. The water vapor (H2O) in the humidified oxygen-containing gas activates the catalyst by removing deposits from the surface of the catalyst (Pt) and wetting the cathode-side catalyst layer 16. The oxygen (O2) in the humidified oxygen-containing gas reacts with the protons (H) that have moved from the anode. + It reacts with the catalyst to form water (H2O). Also, when a humidified nitrogen-containing inert gas is supplied to the cathode electrode 15, the humidified nitrogen-containing inert gas moves through the cathode-side gas diffusion layer 17 to the cathode-side catalyst layer 16. The water vapor (H2O) from the humidified nitrogen-containing inert gas activates the catalyst by removing deposits from the surface of the catalyst (Pt) and wetting the catalyst layer. 【0032】 Figure 3 is a schematic diagram showing an example of the state of a polymer electrolyte fuel cell during activation according to an activation method for a polymer electrolyte fuel cell according to one embodiment of the present invention. Note that Figure 3 is the same as Figure 2 except that a humidified nitrogen-containing inert gas is supplied to the cathode electrode; therefore, the same parts are denoted by the same reference numerals and their explanation is omitted. 【0033】 The hydrogen (H2) in the humidified hydrogen-containing gas supplied to the anode electrode 12 is converted into protons (H2), similar to the case in Figure 2. + The protons then move to the cathode-side catalyst layer 16 by the hydrogen pump. The protons that have moved to the cathode-side catalyst layer 16 accept electrons, and hydrogen (H2) is produced. The humidified nitrogen-containing inert gas supplied to the cathode electrode 15 moves to the cathode-side catalyst layer 16 through the cathode-side gas diffusion layer 17. The water vapor (H2O) of the humidified nitrogen-containing inert gas activates the catalyst by removing deposits from the surface of the catalyst (Pt) and wetting the cathode-side catalyst layer 16. 【0034】 As described above, the polymer electrolyte fuel cell cell 10 is activated. The completion of the activation process can be determined by the output voltage measured by the voltmeter 60. 【0035】 According to the activation method for the polymer electrolyte fuel cell of this embodiment, which has the configuration described above, the fuel cell stack 10s is heated to a high temperature of 100°C or higher using the heating device 50, while a humidified hydrogen-containing gas is supplied to the anode electrode 12 and a humidified oxygen-containing gas or a humidified nitrogen-containing inert gas is supplied to the cathode electrode 15. As a result, the desorption of impurities on the catalyst and the wetting of the anode-side catalyst layer 13, the cathode-side catalyst layer 16, and the polymer electrolyte film 11 by water vapor are promoted, and as a result, the activation of the catalyst proceeds more easily. Furthermore, since the humidified hydrogen-containing gas, humidified oxygen-containing gas, or humidified nitrogen-containing inert gas is pressurized, water vapor can be efficiently supplied to the anode electrode 12 and the cathode electrode 15. Therefore, the polymer electrolyte fuel cell cell 10 can be activated in a shorter time. 【0036】 [Second Embodiment] In the second embodiment of the solid polymer fuel cell activation method, the fuel cell stack 10s is heated to a set temperature using a heating device 50. The set temperature is preferably set within the range of 100°C to 300°C, more preferably 100°C to 200°C, and even more preferably 100°C to 150°C. In this embodiment, heating by the heating device 50 is stopped after the set temperature is reached. With heating stopped, humidifying gas is supplied to the anode and cathode electrodes of the fuel cell stack 10s. Because the temperature of the fuel cell stack 10s decreases when heating is stopped, water vapor can be efficiently supplied to the anode and cathode electrodes even if the pressure when supplying the humidifying gas to the anode and cathode electrodes is lower than in the first embodiment. For this reason, in this embodiment, the humidifying gas supplied to the anode and cathode electrodes does not need to be pressurized. The humidifying gas supplied to the anode side and the cathode side is the same as in the first embodiment. The supply of humidifying gas to the anode and cathode electrodes may be continuous or intermittent. Furthermore, the humidifying gas supplied to the cathode electrode may be intermittently switched between a humidifying oxygen-containing gas and a humidifying nitrogen-containing inert gas. In addition, similar to the first embodiment, a voltage fluctuating within a predetermined range may be applied between the cathode electrode and the anode electrode, with the cathode electrode of the polymer electrolyte fuel cell cell 10 set to positive. 【0037】 According to the solid polymer fuel cell activation method of this embodiment, after the activation of the solid polymer fuel cell cell 10 is advanced by heating the fuel cell stack 10s, the heating is stopped, and then humidified hydrogen-containing gas is supplied to the anode electrode and humidified oxygen-containing gas or humidified nitrogen-containing inert gas is supplied to the cathode electrode. Therefore, water vapor can be efficiently supplied to the anode electrode and cathode electrode without pressurizing the humidified hydrogen-containing gas, humidified oxygen-containing gas or humidified nitrogen-containing inert gas. Note that gas may also be supplied to the anode electrode and cathode electrode while the fuel cell stack 10s is being heated. [Examples] 【0038】 [Example 1] The polymer electrolyte fuel cell is subjected to an activation treatment under the following conditions until the desired battery characteristics are obtained. (i) Heating temperature of polymer electrolyte fuel cell: 120°C (heating until activation process is complete) (ii) Humidified hydrogen-containing gas: Hydrogen-nitrogen mixed gas, gas temperature at cathode supply is 120°C (dew point: 120°C), pressure is 98 kPaG. (iii) Humidified oxygen-containing gas: Oxygen-nitrogen mixed gas, gas temperature at anode supply is 120°C (dew point: 120°C), gas pressure is 98 kPaG. (iv) Voltage application conditions: Hold the voltage at 0.03V for 10 seconds, then repeat the operation of scanning the voltage from 0.03V to 0.9V over 30 seconds. 【0039】 [Example 2] The activation treatment of the polymer electrolyte fuel cell is carried out in the same manner as in Example 1, except that heating is stopped when the temperature of the polymer electrolyte fuel cell reaches 120°C, and the pressure of the humidified hydrogen-containing gas and humidified oxygen-containing gas is set to atmospheric pressure. 【0040】 By performing the activation treatment of the polymer electrolyte fuel cell in Example 1 and Example 2, the time required for the polymer electrolyte fuel cell to be activated is shortened compared to the case where the polymer electrolyte fuel cell is heated at 120°C while humidified hydrogen-containing gas and humidified oxygen-containing gas at atmospheric pressure are supplied. [Explanation of symbols] 【0041】 10. Solid polymer fuel cell 10s fuel cell stack 11 Solid polymer membrane 12 Anodes 13 Anode-side catalyst layer 14 Anode-side gas diffusion layer 15 Cathode poles 16 Cathode-side catalyst layer 17. Cathode-side gas diffusion layer 20 Anode-side gas supply device 21 Humidifier 30. Cathode-side gas supply device 31 Humidifier 40 Power supply 41 Voltage Regulator 50 Heating device 60 Voltmeter 100 Activation Treatment Apparatus

Claims

[Claim 1] A method for activating a polymer electrolyte fuel cell having an electrode membrane structure in which an anode electrode and a cathode electrode are arranged opposite each other via a polymer electrolyte membrane, A method for activating a polymer electrolyte fuel cell, comprising heating the polymer electrolyte fuel cell at a set temperature set within the range of 100°C to 300°C, supplying pressurized humidified hydrogen-containing gas to the anode electrode, and supplying pressurized humidified oxygen-containing gas or humidified nitrogen-containing inert gas to the cathode electrode. [Claim 2] A method for activating a polymer electrolyte fuel cell according to claim 1, wherein the humidified hydrogen-containing gas is heated to the set temperature, and the humidified oxygen-containing gas or the humidified nitrogen-containing inert gas is heated to the set temperature. [Claim 3] The method for activating a polymer electrolyte fuel cell according to claim 2, wherein the dew point of the humidified hydrogen-containing gas is adjusted to the set temperature, and the dew point of the humidified oxygen-containing gas or the humidified nitrogen-containing inert gas is adjusted to the set temperature. [Claim 4] Furthermore, the method for activating a polymer electrolyte fuel cell according to claim 1 or 2, wherein the polymer electrolyte fuel cell is heated while a voltage fluctuating within a predetermined range is applied between the cathode electrode and the anode electrode, with the cathode electrode set to positive. [Claim 5] A method for activating a polymer electrolyte fuel cell having an electrode membrane structure in which an anode electrode and a cathode electrode are arranged opposite each other via a polymer electrolyte membrane, A method for activating a polymer electrolyte fuel cell, comprising heating the polymer electrolyte fuel cell to a set temperature within the range of 100°C to 300°C, then, with the heating stopped, supplying humidified hydrogen-containing gas to the anode electrode and supplying humidified oxygen-containing gas or humidified nitrogen-containing inert gas to the cathode electrode.

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