JP2008077884A - Fuel cell system and its operation control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of suppressing drop in cell performance caused by dissolution or elution of platinum contained in an electrode catalyst layer and enhancing durability; and to provide the operation control method of the fuel cell system. <P>SOLUTION: The operation control method of the fuel cell system 1 containing a fuel cell 10 equipped with a fuel electrode 12 and an oxidant electrode 10 on each side of an electrolyte membrane 11 and generating electric power by supplying fuel gas from a fuel gas supply line 30 to the fuel electrode 12 and oxidant gas from an oxidant supply line 50 to the oxidant electrode 13 is that the load conversion of the fuel cell 10 is detected, and in the load conversion during power generation, or in starting up or stop of the fuel cell 10, when the unit cell voltage of the fuel cell 10 before the load conversion is 0.85 V or higher and steady power generation exceeds 10 seconds, the load conversion is conducted so that the unit cell voltage after the load conversion exceeds 0.75 V. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a polymer electrolyte fuel cell system used as a power source for a mobile object such as an automobile, and a fuel cell capable of suppressing platinum elution when a load varies in a predetermined unit cell voltage and a predetermined time range. The present invention relates to a system operation control method.

  A fuel cell is a clean power generation system in which the product of the electrode reaction is water and has almost no adverse effect on the global environment. In particular, a polymer electrolyte fuel cell is expected to be used as a power source for a moving body such as an automobile because it operates at a lower temperature than others.

  Catalysts in which noble metals containing platinum are supported on carbon are used as electrode catalysts for polymer electrolyte fuel cells. However, when the fuel cells are exposed to a high potential environment during start-up / stop and storage, Dissolution / elution occurs, which is a cause of battery performance degradation.

For example, Patent Document 1 discloses a technique for suppressing the deterioration of the electrode catalyst layer by controlling the time during which the cell voltage is 0.9 V or more within 10 minutes when the fuel cell is stopped.
JP 2004-172106 A

  However, even if the control method of Patent Document 1 is implemented, the dissolution and elution of platinum still proceeds. That is, in Patent Document 1, no consideration is given to the transient state when the fuel cell becomes unloaded, and therefore, good battery performance cannot be maintained over a long period of time, resulting in poor durability.

  Further, in a fuel cell vehicle or the like, the fuel cell is operated with a duty cycle (load fluctuation). In the operation mode with such load fluctuations, the potential of the oxidant electrode changes greatly, so that depending on the conditions, platinum contained in the electrode catalyst layer may be dissolved and eluted, which is a factor in reducing the performance of the fuel cell. .

  The present invention was devised in view of the above-described problems, and can provide a fuel cell having a highly durable fuel cell that can suppress a decrease in cell performance due to dissolution and elution of platinum contained in an electrode catalyst layer. It is an object of the present invention to provide a battery system and an operation control method thereof.

  In order to achieve the above object, an operation control method for a fuel cell system according to the present invention includes a fuel cell having a fuel electrode and an oxidant electrode as electrode catalyst layers on both surfaces of an electrolyte membrane. An operation control method for a fuel cell system that supplies fuel gas from a fuel gas supply system to a fuel electrode and supplies oxidant gas from an oxidant gas supply system to an oxidant electrode to generate power by an electrochemical reaction, When the load shift of the fuel cell is detected, and when the fuel cell is generating power or at the load shift of starting / stopping, the unit cell voltage of the fuel cell before the load shift is 0.85 V (vs RHE). ) When the power generation is steady for more than 10 seconds, the load shift is performed so that the unit cell voltage after the load shift exceeds 0.75V.

  According to the operation control method of the fuel cell system according to the present invention configured as described above, the reduction of platinum oxide without lowering the cell voltage to the reduction potential (0.75 V) of platinum oxide, which is the driving force for elution of platinum. By suppressing the decrease in battery performance due to dissolution / elution of platinum contained in the electrode catalyst layer during load fluctuations, a fuel cell system including a highly durable fuel cell can be provided. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing a basic configuration of a fuel cell system according to the present invention.

  Referring to FIG. 1, a fuel cell system 1 according to the present invention includes a fuel cell (fuel cell stack) 10 having a fuel electrode 12 and an oxidant electrode 13, and one of the fuel electrodes 12 of the fuel cell 10. A connected fuel gas supply system 30, a fuel gas discharge system 40 connected to the other of the fuel electrodes 12, an oxidant gas supply system 50 connected to one of the oxidant electrodes 13 of the fuel cell 10, and An oxidant gas discharge system 60 connected to the other of the oxidant electrodes 13 is generally configured.

  In the fuel cell 10, a fuel electrode 12 and an oxidant electrode 13 are stacked as an electrolytic catalyst layer on both sides of the electrolyte membrane 11. The fuel cell 10 includes a load transition detecting unit 21 that detects a load transition of the fuel cell 10, an operation time measuring unit 22 that detects a duty cycle operation time of the fuel cell 10, and a unit cell resistance value of the fuel cell 10. Cell resistance detecting means 23 for detecting the unit cell voltage and cell voltage detecting means 24 for detecting the unit cell voltage of the fuel cell 10 are provided.

  A secondary battery 25 is connected in parallel between the fuel electrode 12 and the oxidant electrode 13 of the fuel cell 10. When the power of the fuel cell 10 is insufficient with respect to the required load, by supplying power from the secondary battery 25 connected in parallel to the fuel cell 10, it is possible to supply the insufficient power.

  The fuel gas supply system 30 is, for example, a flow path for supplying hydrogen as a fuel gas, and is provided with a hydrogen cylinder 31 and a flow rate control valve 32 for adjusting the hydrogen supply amount of the hydrogen cylinder 31 in order from the upstream side. ing.

  The fuel gas discharge system 40 is a flow path for circulating or discharging the discharged hydrogen that has passed through the fuel electrode 12, and is provided with a compressor 41, a check valve 42, and a switching valve 43 in order from the upstream side. ing. A circulation passage 44 is branchedly connected between the compressor 41 and the check valve 42 of the fuel gas discharge system 40, and the circulation passage 44 is downstream of the flow rate control valve 32 in the fuel gas supply system 30. It is connected to the. A check valve 45 is provided in the circulation channel 44, and the switching valve 43 is closed and the compressor 41 is operated, so that the discharged hydrogen is supplied from the fuel gas discharge system 40 to the fuel via the circulation channel 44. It is circulated to the gas supply system 30. That is, the exhausted hydrogen that has passed through the fuel electrode 12 without being used for the power generation reaction in the fuel cell 10 passes through the circulation passage 44 and is supplied again to the fuel gas supply passage 10. When the exhausted hydrogen contains a large amount of substances other than hydrogen, such as nitrogen, the switching valve 43 of the fuel gas exhaust system 40 is opened to discharge the exhausted hydrogen to the outside of the system.

  The oxidant gas supply system 50 is, for example, a flow path for supplying air as an oxidant gas. The compressor 51, the upstream three-way valve 52, a humidifier 53 as a gas humidification control unit, and a downstream side in that order from the upstream side. A three-way valve 54 is provided. An oxidant gas bypass passage 55 is connected between the upstream three-way valve 52 and the downstream three-way valve 54. Air introduced from outside air by operating the compressor 51 is supplied to the oxidant electrode 13 via the oxidant gas supply system 50. The humidifier 53 provided in the oxidant gas supply system 50 humidifies the air supplied to the oxidant electrode 13. By adjusting the supply gas humidity to a predetermined value by the humidifier 53, it becomes possible to suppress dissolution / elution of platinum contained in the electrode catalyst layer when the load fluctuates. In particular, as in this embodiment, it is effective to provide a humidifier 53 that can adjust the supply gas humidity on the oxidant gas supply system 50 side. It is also possible to supply the oxidant electrode 13 without passing through the humidifier 53 by switching the three-way valves 52 and 53 and introducing air into the bypass flow passage 55.

  In the present embodiment, the humidifier 53 is provided in the oxidant gas supply system 50. However, the present invention is not limited to this, and may be provided in the fuel gas supply system 30 and allows a mounting space. If desired, the oxidant gas supply system 50 and the fuel gas supply system 30 may be interposed.

  The oxidant gas discharge system 60 is a flow path for discharging discharged air that has passed through the oxidant electrode 13 to the outside, and is open to the atmosphere. That is, the exhaust air that has not been used for the power generation reaction in the fuel cell 10 is exhausted to the outside of the system via the oxidant gas exhaust system 60.

  Next, an operation control method of the fuel cell system 1 configured as described above will be described.

  In the electrochemical reaction of the fuel cell 10, protons generated by the oxidation of the fuel on the electrode catalyst layer of the fuel electrode (anode electrode) 12 pass through the solid polymer electrolyte polymer dispersed in the electrode catalyst layer to the electrolyte membrane 11. , Further passes through the electrolyte membrane 11 and moves to the oxidant electrode (cathode electrode) 13 side. Thereafter, it passes through the solid polymer electrolyte polymer dispersed in the electrode catalyst layer of the oxidant electrode 13 and reaches the electrode catalyst of the oxidant electrode 13, and reacts with oxygen gas and electrons that have passed through the external circuit to react with water. Generate.

  As described above, during operation of the fuel cell 10, platinum (Pt) contained in the electrode catalyst layer is likely to elute, particularly in an operation mode with load fluctuation. This is because the change in the electronic state of platinum due to the platinum oxidation reaction (Pt → PtO) and the platinum oxide reduction reaction (PtO → Pt) particularly when the load fluctuates (when the unit cell voltage of the fuel cell 10 changes). It is thought that it is related as a main factor of dissolution / elution phenomenon. In particular, when a constant holding operation is performed for a time exceeding 10 seconds at a cell voltage of 0.85 V or higher, the amount of platinum oxide (PtO) formed increases, and the electrode catalyst is reduced when this is reduced to platinum (Pt). Dissolution / elution of platinum (Pt) contained in the layer easily proceeds.

  Based on the above knowledge, the first to third operation control methods of the fuel cell system 1 according to the present invention will be described.

As described above, the fuel cell 10 of the present embodiment includes the load transition detection unit 21, the cell voltage measurement unit 24, and the operation time measurement unit 22. Using these detection means, the first operation control method is such that the unit cell voltage before the load change is a predetermined value (0.85 V) when the fuel cell 10 is generating power or at the time of starting or stopping the load transition. When the operation exceeding the fixed time (10 seconds) is detected as described above, the reduction potential of platinum oxide (PtO → Pt reduction potential of 0.75 V) is used as the driving force for elution of the unit cell voltage after the load shift. Operation control is performed so that the PtO is not reduced without lowering the potential. By performing such operation control, the dissolution and elution of platinum contained in the electrode catalyst layer of the fuel cell 10 accompanying the duty cycle can be suppressed, and the fuel cell system including the fuel cell 10 having high durability 1 can be realized.
[First operation control method]
FIG. 2 is a flowchart specifically showing the first operation control method.

  The first operation control method will be described with reference to FIGS. 1 and 2. The load transition detection means 21 always detects the load state of the fuel cell 10. Whether or not the load has been shifted is determined by whether or not the voltage detected by the cell voltage detecting means 24 has changed. When the load transition detection means 21 detects a load transition (step 1; hereinafter referred to as “S1”), the cell voltage detection means 24 sets the unit cell voltage (V1) before the load transition to a predetermined value (0). .85V) or more is detected (S2).

  In step 2, when the unit cell voltage (V1) before the load shift is less than the predetermined value (0.85V) (V1 <0.85V) (S2: NO), the load shift is performed as it is and the process is terminated. (S3). On the other hand, in step 2, when the unit cell voltage (V1) before the load shift is equal to or higher than the predetermined value (0.85V) (V1 ≧ 0.85V) (S2: YES), the operation time measuring means 22 uses the unit cell voltage (V1). It is detected whether the cell voltage (V1 ≧ 0.85V) exceeds a predetermined time (10 seconds) (S4).

  In step 4, when the unit cell voltage (V1 ≧ 0.85V) before the load shift is equal to or less than the predetermined time (10 seconds) (T1 ≦ 10 sec.) (S4: NO), the load shift is performed as it is. The process ends (S5). On the other hand, in step 4 (S4), when the unit cell voltage (V1 ≧ 0.85V) before the load shift exceeds a predetermined time (10 seconds) (T1> 10 sec.) (S4: YES), the cell voltage detection is performed. The means 24 detects whether or not the unit cell voltage (V2) after the load shift exceeds a predetermined value (0.75V) (S6).

  In step 6, when the unit cell voltage (V2) after the load shift exceeds the predetermined value (0.75V) (V2> 0.75V), the load shift is performed as it is and the process is terminated (S7). On the other hand, when the unit cell voltage (V2) after the load shift is not more than the predetermined value (0.75V) in step 6 (V2 ≦ 0.75V) (S6: NO), the process proceeds to step 6 (S6). Returning, operation control is performed so that the unit cell voltage after load transfer exceeds the reduction potential (0.75 V) of platinum oxide.

That is, according to the first operation control method, by suppressing the reduction of platinum oxide without reducing the cell voltage to the reduction potential (0.75 V) of platinum oxide, which is the driving force for elution of platinum, A decrease in battery performance due to dissolution and elution of platinum contained in the electrode catalyst layer can be suppressed, and the fuel cell system 1 including the fuel cell 10 having high durability can be provided.
[Second operation control method]
When the required load from the vehicle is large, for example, when the fuel cell 10 is generating power or at the time of starting / stopping the load, the unit cell voltage before the load change is a predetermined value (0.85 V) or more and constant. When a load that lowers the unit cell voltage obtained after the transition to the load to the reduction potential of platinum oxide (0.75 V), which is the driving force for platinum elution, is required after driving for more than 10 seconds. The following operation control is effective.

  That is, the second operation control method reduces the amount of platinum oxide (PtO) formed by performing a constant holding operation in a potential range of 0.75 V or more and less than 0.85 V immediately before the load shift and for less than 10 seconds. By reducing the amount reduced to platinum (Pt), the load transfer immediately after that is effective in suppressing the dissolution and elution of platinum contained in the electrode catalyst layer accompanying the duty cycle. It is effective as an operation control method under conditions where dissolution and elution are likely to proceed.

  FIG. 3 is a flowchart specifically showing the second operation control method.

  The second operation control method will be described with reference to FIGS. 1 and 3. The load transition detection means 21 always detects the load state of the fuel cell 10, and when this load transition detection means 21 detects a load transition (S11), the cell voltage detection means 24 causes the unit cell voltage (before the load transition) ( It is detected whether or not (V1) is a predetermined value (0.85V) or more (S12).

  In step 12, when the unit cell voltage (V1) before the load shift is less than the predetermined value (0.85V) (V1 <0.85V) (S12: NO), the load shift is performed as it is and the process is terminated. (S13). On the other hand, when the unit cell voltage (V1) before the load transition is equal to or higher than the predetermined value (0.85V) in step 12 (V1 ≧ 0.85V) (S12: YES), the operation time measuring means 22 performs the unit. It is detected whether the cell voltage (V1 ≧ 0.85V) exceeds a predetermined time (10 seconds) (S14).

  In step 14, if the unit cell voltage (V1 ≧ 0.85V) before the load shift is equal to or shorter than the predetermined time (10 seconds) (T1 ≦ 10 sec.) (S14: NO), the load shift is performed as it is and the process is performed. The process ends (S15). On the other hand, when the unit cell voltage (V1 ≧ 0.85 V) before the load shift exceeds the predetermined time (10 seconds) in step 14 (T1> 10 sec.) (S14: YES), the cell voltage detecting means 24 It is detected whether the unit cell voltage (V2) after the load shift exceeds a predetermined value (0.75V) (S16).

  If the unit cell voltage (V2) after the load shift exceeds the predetermined value (0.75V) in step 16 (V2> 0.75V) (S16: YES), the load shift is performed as it is and the process is terminated (S16: YES). S17). On the other hand, when the unit cell voltage (V2) after the load shift is equal to or less than the predetermined value (0.75V) in step 16 (V2 ≦ 0.75V) (S16: NO), the predetermined time (T2; T2 < 10 sec.) And the unit cell voltage (V2) reaches the range of 0.75 V ≦ unit cell voltage <0.85 V (S18), the load is shifted (S19), and the process is terminated.

That is, according to the second operation control method, the unit cell voltage is in the range of 0.75 V or more and less than 0.85 V, and the constant holding operation of less than 10 seconds, the amount of platinum oxide formed is reduced, In order to reduce the amount reduced to platinum, it is possible to suppress a decrease in battery performance due to dissolution and elution of platinum contained in the electrode catalyst layer at the time of load change, and a fuel cell including a highly durable fuel cell 10 A system 1 can be provided.
[Operation of the first and second operation control methods]
Next, the operation of the first operation control method and the second operation control method will be considered with reference to FIGS.

  The amount of Pt elution varies depending on the cycle period of the cell voltage. For example, this phenomenon will be described with reference to FIG.

  FIG. 5 is an explanatory diagram showing the relationship between the duty cycle and the platinum elution ratio. FIG. 5 shows the case where the unit cell voltage fluctuates in the range of 0.6 V to 0.95 V. When A shown in (a) fluctuates at 10 sec / cycle, B shown in (b) fluctuates at 60 sec / cycle. This is the case.

  As shown in FIG. 5C, in the case of B of 60 sec / cycle, the platinum elution ratio increases rapidly, and the platinum elution ratio exceeds 40% in about 2000 cycles. On the other hand, in the case of 10 sec / cycle of A, the platinum elution rate rises slowly, the platinum elution rate exceeds 40% at about 5000 cycles, and the platinum elution rate does not exceed 50% even after reaching 10,000 cycles. This shows that the platinum elution ratio is small when the duty cycle is 10 sec / cycle or less.

  In addition, the holding time of the cathode electrode at a high potential affects the amount of platinum oxide (PtO) formed, and the amount of PtO formed varies depending on the potential of the cathode electrode.

  When the amount of PtO formation is large, the amount of Pt dissolution is smaller when cycling at a higher potential (> 0.75 V) than the reduction potential of PtO (0.75 V). For example, FIG. Explain the phenomenon. FIG. 6 is an explanatory diagram showing the relationship between the voltage fluctuation range and the platinum elution ratio.

  FIG. 6 shows the case where the unit cell voltage fluctuates at 60 sec / cycle. When C shown in (a) fluctuates in the range of 0.80V to 0.95V, D shown in (b) starts from 0.60V. This is a case where the voltage fluctuates in the range of 0.95V.

  As shown in FIG. 6C, when the voltage fluctuates in the range of 0.80V to 0.95V of C, the voltage fluctuates in the range of 0.80V to 0.95V of C, as compared with the case where the voltage fluctuates in the range of 0.60V to 0.95V. The platinum elution rate is rising slowly. Accordingly, it can be seen that the platinum elution ratio is small for the unit cell voltage to be higher than 0.75V.

7 and 8 are explanatory diagrams showing the relationship between the voltage fluctuation range and the platinum elution ratio.
FIG. 7 shows the case where the unit cell voltage fluctuates at 60 sec / cycle, and E shown in (a) changes when the voltage fluctuates in the range of 0.80 V to 0.95 V, and F shown in (b) starts from 0.60 V. When the voltage fluctuates in two steps in the range of 0.80 V and 0.80 V to 0.95 V, G shown in (c) is the case in which the voltage fluctuates in the range of 0.60 V to 0.95 V. Note that E shown in (a) corresponds to claim 1 and the first operation control method, F shown in (b) corresponds to claim 2 and second operation control method, and G shown in (c). Corresponds to the conventional driving method.

As shown in FIG. 8, when the voltage fluctuates in the range of 0.80 V to 0.95 V of E, as compared to the case of the voltage fluctuating in the range of 0.60 V to 0.95 V of G, and 0. When the voltage fluctuates in two steps in the range of 60 V to 0.80 V and 0.80 V to 0.95 V, the platinum elution ratio increases more slowly. Further, when the voltage fluctuates in the range of 0.80V to 0.95V of E, compared to the case of voltage fluctuation in two steps in the range of F from 0.60V to 0.80V and 0.80V to 0.95V. In this case, the platinum elution ratio increases more gradually. This shows that the platinum elution ratio is small when the cell voltage does not fall below 0.80V.
[Third operation control method]
In the third operation control method, the unit cell voltage at the time of the high load before the load shift is 0.85 V or more at the time of the load shift from the high load of the power generation or the stop of the fuel cell 10 to the low load, and When the unit cell voltage at the time of low load after the load shift is less than 0.75, the supply gas humidity is set to a predetermined condition. The predetermined condition is that the humidity is adjusted such that the supply gas humidity after the load shift is lower than the supply gas humidity before the load shift, and the humidity adjusted gas is supplied to the fuel cell 10.

  Further, when the supply gas humidity after the load shift is Y (% RH) and the supply gas humidity before the load shift is X (% RH), the supply gas humidity X and Y are It is preferable to have a relationship of 1 <X / Y <20. This is because, when X / Y is smaller than 1, the oxidation current of platinum contained in the electrode catalyst layer increases, so that the dissolution / elution of platinum is likely to proceed and the durability may be lowered. . On the other hand, when X / Y is greater than 20, although the dissolution and elution resistance of platinum is excellent, the electrode catalyst layer continues to be in a low water content state, so that the solid polymer electrolyte polymer (ionomer) or the electrolyte membrane in the electrode catalyst layer This is because the battery 11 may be dried and it may be difficult to obtain good battery performance.

  Furthermore, the fuel cell system 1 according to the present embodiment includes the cell resistance detection unit 23, and stops the humidification control when the detected resistance value by the cell resistance detection unit 23 is equal to or greater than a predetermined value. By such operation control, it is possible to avoid in advance the irrecoverable deterioration of the solid polymer electrolyte polymer (ionomer) or the electrolyte membrane 11 in the catalyst layer due to the electrode catalyst layer being kept in a low water content state. If the power of the fuel cell 10 is insufficient with respect to the required load, the insufficient power can be supplied by the secondary battery 25 connected in parallel to the fuel cell 10.

  By controlling the operation as described above, the oxidation current of platinum can be suppressed and the formation of platinum oxide (PtO) can be suppressed, so that the dissolution / elution of platinum contained in the electrode catalyst layer accompanying the duty cycle is suppressed. It is effective as an operation control method under conditions where platinum dissolution / elution is likely to proceed.

  FIG. 4 is a flowchart specifically showing the third operation control method.

  A third operation control method will be described with reference to FIGS. 1 and 4. The load transition detection means 21 always detects the load state of the fuel cell 10, and when this load transition detection means 21 detects a load transition (S21), the cell voltage detection means 24 causes the unit cell voltage (before the load transition) ( It is detected whether or not (V1) is a predetermined value (0.85V) or more (S22).

  In step 22, when the unit cell voltage (V1) before the load shift is less than the predetermined value (0.85V) (V1 <0.85V) (S22: NO), the process is terminated. On the other hand, when the unit cell voltage (V1) before the load shift is equal to or higher than the predetermined value (0.85V) in step 22 (V1 ≧ 0.85V) (S22: YES), the humidifier 53 supplies the supplied air. The humidification control is started (S23).

  This humidification control is continued until the humidification amount of the supply air reaches a predetermined value. When the humidification amount reaches the predetermined value in step 24, supply of the humidification air to the fuel cell 10 is started (S25).

  Then, it is detected by the cell resistance detection means 23 whether or not the unit cell resistance is at a predetermined value (S26). If the unit cell resistance is not at the predetermined value in step 26, the humidification control of the humidifier 53 is stopped (S27). On the other hand, when the unit cell resistance has reached a predetermined value, the load is shifted so that the unit cell voltage after the load shift becomes 0.75 V or more (S28), and the process is terminated.

  Next, the operation of the third operation control method will be considered with reference to FIG. FIG. 9 is an explanatory diagram showing the relationship between the gas humidification amount and the platinum elution ratio.

  In FIG. 9, H is 100% R.D. H. The platinum elution ratio of the humidification amount of I, I is 70% R.D. H. The platinum elution ratio of the amount of humidification, and J is 50% R.D. H. It shows the platinum elution ratio of the amount of humidification. As shown in the figure, the platinum elution ratio increases more gradually as the humidification amount of the supply gas decreases. As a result, the humidification amount of the supply gas is reduced to 50% R.D. H. It can be seen that the platinum elution ratio decreases as the amount decreases closer to.

  That is, according to the third operation control method, by setting the supply gas humidity to the electrode catalyst layer to a predetermined humidity, it is possible to suppress platinum oxidation current and suppress formation of platinum oxide. It is possible to provide a fuel cell system 1 including a fuel cell 10 having high durability, which can suppress a decrease in battery performance due to dissolution / elution of platinum contained in the electrode catalyst layer during fluctuation.

  As described above, according to the fuel cell system 1 and the operation control method thereof according to the present invention, durability superior to the conventional one can be obtained. As a result, a highly reliable fuel cell system 1 can be realized.

  The present invention can be applied to a fuel cell system.

It is the schematic which shows the basic composition of the fuel cell system concerning the present invention. It is a flowchart which shows the 1st driving | operation control method concretely. It is a flowchart which shows the 2nd driving | operation control method concretely. It is a flowchart which shows the 3rd driving | running control method concretely. It is explanatory drawing which shows the relationship between a duty cycle and a platinum elution ratio. It is explanatory drawing which shows the relationship between a voltage fluctuation range and a platinum elution ratio. It is explanatory drawing which shows the fluctuation | variation of the unit cell voltage in 60 sec / cycle. It is explanatory drawing which shows the relationship between a voltage fluctuation range and a platinum elution ratio. It is explanatory drawing which shows the relationship between gas humidification amount and a platinum elution ratio.

Explanation of symbols

1 Fuel cell system,
10 Fuel cell,
11 electrolyte membrane,
12 Fuel electrode,
13 Oxidant electrode,
21 load transition detection means,
22 Operating time measuring means,
23 Cell resistance detection means,
24 cell voltage detection means,
25 Secondary battery,
30 Fuel gas supply system,
31 Hydrogen cylinder,
32 Flow control valve,
40 Fuel gas discharge system,
41 compressor,
42 check valve,
43 switching valve,
44 circulation channel,
45 check valve,
50 oxidant gas supply system,
51 compressor,
52 upstream three-way valve,
53 Humidifier,
54 Three-way valve on the downstream side,
55 Bypass channel,
60 Oxidant gas discharge system.

Claims (10)

A fuel cell having a fuel electrode and an oxidant electrode as electrode catalyst layers on both surfaces of the electrolyte membrane is provided. Fuel gas is supplied from the fuel gas supply system to the fuel electrode of the fuel cell and oxidized to the oxidant electrode. An operation control method for a fuel cell system in which an oxidant gas is supplied from an agent gas supply system to generate power by an electrochemical reaction,
The fuel cell load transition is detected, and the unit cell voltage of the fuel cell before the load transition is 0.85 V or more and 10 seconds when the fuel cell is generating power, or at the time of starting or stopping the load. The operation control method for a fuel cell system is characterized in that the load shift is performed so that the unit cell voltage after the load shift exceeds 0.75 V when the stationary power generation exceeds the threshold. A fuel cell having a fuel electrode and an oxidant electrode as electrode catalyst layers on both surfaces of the electrolyte membrane is provided. Fuel gas is supplied from the fuel gas supply system to the fuel electrode of the fuel cell and oxidized to the oxidant electrode. An operation control method for a fuel cell system in which an oxidant gas is supplied from an agent gas supply system to generate power by an electrochemical reaction,
The fuel cell load transition is detected, and the unit cell voltage of the fuel cell before the load transition is 0.85 V or more and 10 seconds when the fuel cell is generating power, or at the time of starting or stopping the load. If the unit cell voltage before load transition is set to 0.75 V or more and less than 0.85 V and steady power generation is performed for less than 10 seconds, the load transition is performed. A fuel cell system operation control method. A fuel cell having a fuel electrode and an oxidant electrode as electrode catalyst layers on both surfaces of the electrolyte membrane is provided. Fuel gas is supplied from the fuel gas supply system to the fuel electrode of the fuel cell and oxidized to the oxidant electrode. An operation control method for a fuel cell system in which an oxidant gas is supplied from an agent gas supply system to generate power by an electrochemical reaction,
The unit cell voltage at the time of high load before the load shift is less than 0.75 V at the time of the load shift from the high load to either the power generation or the stop of the fuel cell, and at the time of the low load after the load shift When the unit cell voltage is 0.85 V or more, at least one of the supply gas humidity of the fuel gas and the oxidant gas is set to a predetermined condition, and then load transfer is performed. Control method of fuel cell system.   The predetermined condition is that the humidity of the supply gas is adjusted so that the supply gas humidity after the load shift is lower than the supply gas humidity before the load shift, and the humidity adjusted gas is supplied to the fuel cell. The operation control method for a fuel cell system according to claim 3, wherein   When the supply gas humidity after the load shift is Y (% RH) and the supply gas humidity before the load shift is X (% RH), the supply gas humidity X, Y is 1 <X The fuel cell system control method according to claim 4, wherein a relationship of / Y <20 is satisfied.   The unit cell resistance value of the fuel cell is detected, and the humidification control is stopped when the resistance value exceeds a predetermined value. Control method for the fuel cell system of the present invention. A fuel cell having a fuel electrode and an oxidant electrode as electrode catalyst layers on both surfaces of the electrolyte membrane, a fuel gas supply system that supplies fuel gas to the fuel electrode, and a fuel gas that has passed through the fuel electrode is discharged. A fuel cell system comprising: a fuel gas discharge system; an oxidant gas supply system that supplies an oxidant gas to the oxidant electrode; and an oxidant gas discharge system that discharges the oxidant gas that has passed through the oxidant electrode. In
A load transition detecting means for detecting a load transition either during power generation of the fuel cell or starting / stopping; a cell voltage detecting means for detecting a unit cell voltage of the fuel cell; An operating time measuring means for measuring a duty cycle operating time is provided.   The fuel cell system according to claim 7, wherein a gas humidification control unit is disposed in at least one of the fuel gas supply system and the oxidant gas supply system in the fuel cell.   9. The fuel cell system according to claim 8, wherein the fuel cell is provided with cell resistance detection means for detecting a unit cell resistance value of the fuel cell.   10. The fuel cell according to claim 7, wherein a secondary battery is provided in parallel with the fuel cell, and power is supplied by the secondary battery during operation control of the fuel cell system. 11. system.

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