Control device and fuel cell system

Abstract

To provide a technique that reduces noise from a compressor for a fuel cell system.SOLUTION: A controller that a fuel cell system 10 includes comprises a reception part and a control part. When the reception part receives an electric power generation stop command during a vehicle drive, the control part closes sealing valves 116, 118, and also sets an opening of a bypass valve 119 to a first opening smaller than its maximum opening and a rotation speed of a compressor 112 to a predetermined rotation speed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device and a fuel cell system. [Background technology]

[0002] In recent years, research and development into fuel cells has been conducted to contribute to energy efficiency in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Regarding fuel cells, there is a fuel cell system equipped with a fuel cell stack including power-generating cells. The fuel cell system can be mounted on a mobile object such as a vehicle. In a fuel cell system mounted on a mobile object, power generation of the power-generating cells may be stopped even when the mobile object is operating.

[0004] Patent Document 1 discloses that idle control is performed when a signal related to stopping power generation is received while the moving object is in operation. In the idle control disclosed in Patent Document 1, power generation by the power generation cell is performed with less power than the power consumption of the compressor (air pump) that outputs the oxidant gas supplied to the fuel cell stack. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-108930 Summary of the Invention [Problem to be solved by the invention]

[0006] When a compressor is operating, it generates noise, and technology that can help reduce this noise is highly anticipated.

[0007] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0008] According to an aspect of the present invention, there is provided a fuel cell stack including a power generation cell, a battery for storing power generated by the power generation cell, an oxidant gas supply channel connected to the fuel cell stack, an oxidant gas discharge channel connected to the fuel cell stack, a bypass channel having one end connected to the oxidant gas supply channel and the other end connected to the oxidant gas discharge channel, a compressor for supplying oxidant gas to the oxidant gas supply channel, the oxidant gas supply channel between a connection part to which the one end of the bypass channel is connected and the fuel cell stack, and the oxidant gas discharge channel between a connection part to which the other end of the bypass channel is connected and the fuel cell stack. a control device provided in a fuel cell system having one or more sealing valves provided in at least one of the paths and a bypass valve provided in the bypass path and having an adjustable opening, the control device comprising: a receiving unit that receives commands; and a control unit that performs control based on the commands, wherein when the receiving unit receives a power generation stop command to stop power generation of the power generation cell while the fuel cell system is operating, the control unit closes the sealing valve and sets the opening of the bypass valve to a first opening that is smaller than the maximum opening, and sets the rotational speed of the compressor to a predetermined rotational speed that is lower than the rotational speed during power generation of the power generation cell. [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce noise generated from a compressor. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a fuel cell system. [Figure 2] FIG. 2 is a diagram showing the fuel cell system when idle control is executed. [Figure 3] FIG. 3 is a flowchart showing the procedure of the idle control process. [Figure 4] FIG. 4 is a time chart showing the behavior of the fuel cell system during idle control processing. DETAILED DESCRIPTION OF THE INVENTION

[0011] [1 Configuration of fuel cell system 10] 1 is a schematic diagram of a fuel cell system 10. The fuel cell system 10 is mounted on a vehicle (fuel cell vehicle), but is not limited to this. For example, the object on which the fuel cell system 10 is mounted may be a moving body other than a vehicle, such as a ship, an aircraft, or a robot. The object on which the fuel cell system 10 is mounted may also be a stationary power source in a facility, a home, or the like.

[0012] In the fuel cell system 10, a fuel gas and an oxidant gas are used as reactant gases. The fuel gas is a hydrogen-containing gas. The oxidant gas is an oxygen-containing gas such as air. Each of the fuel gas and the oxidant gas is supplied to the fuel cell stack 12 and subjected to an electrochemical reaction. In this specification, the fuel gas discharged from the fuel cell stack 12 without being subjected to the electrochemical reaction is also referred to as fuel off-gas. In this specification, the oxidant gas discharged from the fuel cell stack 12 without being subjected to the electrochemical reaction is also referred to as oxidant off-gas.

[0013] The fuel cell system 10 includes a fuel cell stack 12, a tank 14, an anode system 16, a cathode system 18, a cooling system 20, and a control device 22. Electric power generated by the fuel cell stack 12 is supplied to a load 26. The load 26 includes a battery 26A that stores the power generated by the fuel cell stack 12, and a vehicle drive motor 26B. The tank 14 is filled with high-pressure fuel gas.

[0014] The fuel cell stack 12 includes a fuel gas supply port 12a that supplies fuel gas to the inside of the fuel cell stack 12 and a fuel gas discharge port 12b that discharges fuel off-gas from the inside of the fuel cell stack 12. The fuel cell stack 12 includes an oxidant gas supply port 12c that supplies oxidant gas to the inside of the fuel cell stack 12 and an oxidant gas discharge port 12d that discharges oxidant off-gas from the inside of the fuel cell stack 12. The fuel cell stack 12 includes a refrigerant supply port 12e that supplies refrigerant to the inside of the fuel cell stack 12 and a refrigerant discharge port 12f that discharges the refrigerant from the inside of the fuel cell stack 12.

[0015] The fuel cell stack 12 has a plurality of power generating cells 28. Each of the plurality of power generating cells 28 has the same configuration. Each power generating cell 28 includes a membrane electrode assembly 30, a first separator 32, and a second separator 34. The membrane electrode assembly 30 is sandwiched between the first separator 32 and the second separator 34. One of the plurality of power generating cells 28 is shown in FIG. 1.

[0016] The first separator 32 and the second separator 34 are formed from a metal sheet having a corrugated cross section. In two adjacent power generating cells 28, the first separator 32 of one power generating cell 28 and the second separator 34 of the other power generating cell 28 are joined to each other. A cell cooling channel (not shown) is formed between the first separator 32 and the second separator 34. The cell cooling channel communicates with the refrigerant supply port 12e and the refrigerant discharge port 12f.

[0017] The membrane electrode assembly 30 includes an electrolyte membrane 36, an anode 38, and a cathode 40. The electrolyte membrane 36 is interposed between the anode 38 and the cathode 40. An anode flow path 42 is formed between the first separator 32 and the anode 38. A cathode flow path 44 is formed between the second separator 34 and the cathode 40. The anode flow path 42 communicates with the fuel gas supply port 12a and the fuel gas discharge port 12b. The cathode flow path 44 communicates with the oxidant gas supply port 12c and the oxidant gas discharge port 12d.

[0018] A temperature sensor 46 is provided near the fuel gas discharge port 12b. For example, the temperature sensor 46 is provided in the fuel gas discharge channel 86 connected to the fuel gas discharge port 12b. The temperature sensor 46 detects the temperature of the fuel gas. The temperature sensor 46 may be provided near the oxidant gas discharge port 12d. For example, the temperature sensor 46 may be provided in the oxidant gas discharge channel 108 connected to the oxidant gas discharge port 12d. In this case, the temperature sensor 46 detects the temperature of the oxidant gas. The temperature of the fuel gas or oxidant gas near the discharge port of the fuel cell stack 12 (gas temperature) is the representative temperature of the fuel cell stack 12. In other words, the gas temperature corresponds to the temperature of the fuel cell stack 12 (stack temperature).

[0019] The anode system 16 includes a fuel gas supply channel 84, a fuel gas discharge channel 86, a circulation channel 88, and a drain channel 90. The anode system 16 also includes an injector 94, an ejector 96, a gas-liquid separator 98, and a drain valve 100.

[0020] The fuel gas supply path 84 is connected to the outlet of the tank 14 and the fuel gas supply port 12a of the fuel cell stack 12. The fuel gas supply path 84 is provided with an injector 94 and an ejector 96. The ejector 96 is disposed closer to the fuel cell stack 12 than the injector 94.

[0021] The fuel gas discharge path 86 is connected to the fuel gas discharge port 12b of the fuel cell stack 12 and a supply port of the gas-liquid separator 98. The circulation path 88 is connected to the exhaust port of the gas-liquid separator 98 and the ejector 96.

[0022] The drainage channel 90 is connected to the drain outlet of the gas-liquid separator 98 and to the inlet of a diluter 121. The outlet of the diluter 121 is connected to an exhaust port provided in the vehicle. The drainage channel 90 is provided with a drain valve 100.

[0023] The cathode system 18 includes an oxidant gas supply channel 106, an oxidant gas discharge channel 108 (discharge channel), and a bypass channel 110. The cathode system 18 also includes a compressor 112 (oxidant gas supplier), a humidifier 114, a first shutoff valve 116, a second shutoff valve 118, and a bypass valve 119.

[0024] The oxidizing gas supply channel 106 is connected to an air intake port provided in the vehicle and an oxidizing gas supply port 12c of the fuel cell stack 12. The oxidizing gas supply channel 106 is provided with a compressor 112, a first shut-off valve 116, and a humidifier supply channel 114A for the humidifier 114. A portion of the oxidizing gas supply channel 106 that is arranged upstream of the humidifier 114 is referred to as the oxidizing gas supply channel 106A. A portion of the oxidizing gas supply channel 106 that is arranged downstream of the humidifier 114 is referred to as the oxidizing gas supply channel 106B. The oxidizing gas supply channel 106A is provided with the compressor 112 and the first shut-off valve 116.

[0025] The compressor 112 is a device that supplies the oxidant gas to the oxidant gas supply channel 106A. The compressor 112 may be a turbo compressor that uses an air bearing on its rotating shaft. In a turbo compressor, the rotating shaft is levitated by air. The first shut-off valve 116 is an on-off valve that opens and closes the oxidant gas supply channel 106A. The first shut-off valve 116 is disposed closer to the humidifier 114 than the compressor 112.

[0026] The oxidant gas discharge channel 108 is connected to the oxidant gas discharge port 12d of the fuel cell stack 12 and to the inlet of the diluter 121. The oxidant gas discharge channel 108 is provided with a humidifier discharge channel 114B of the humidifier 114 and a second shutoff valve 118. A portion of the oxidant gas discharge channel 108 that is arranged upstream of the humidifier 114 is referred to as the oxidant gas discharge channel 108A. A portion of the oxidant gas discharge channel 108 that is arranged downstream of the humidifier 114 is referred to as the oxidant gas discharge channel 108B. The oxidant gas discharge channel 108B is provided with the second shutoff valve 118. The second shutoff valve 118 is an on-off valve that opens and closes the oxidant gas discharge channel 108B.

[0027] The bypass channel 110 connects the oxidant gas supply channel 106 and the oxidant gas discharge channel 108. One end of the bypass channel 110 is connected to the oxidant gas supply channel 106A between the compressor 112 and the first shut-off valve 116. The first shut-off valve 116 is located in the oxidant gas supply channel 106A between the fuel cell stack 12 and a connection point CP1 to which one end of the bypass channel 110 is connected. The other end of the bypass channel 110 is connected to the oxidant gas discharge channel 108B downstream of the second shut-off valve 118. The second shut-off valve 118 is located in the oxidant gas discharge channel 108B between the fuel cell stack 12 and a connection point CP2 to which the other end of the bypass channel 110 is connected. The bypass channel 110 is provided with a bypass valve 119. The bypass valve 119 is an adjustment valve whose opening degree can be adjusted. An example of the adjustment valve is a butterfly valve. The amount of oxidant gas supplied to the fuel cell stack 12 is adjusted according to the opening degree of the bypass valve 119 .

[0028] The cooling system 20 includes a refrigerant flow path 120. The cooling system 20 also includes a pump 126, a radiator 128, a temperature sensor 130, and a flow dividing valve 132.

[0029] The coolant flow path 120 circulates a coolant between the fuel cell stack 12 and the radiator 128. The coolant is, for example, water containing ethylene glycol. The coolant flow path 120 includes a coolant supply path 122, a coolant discharge path 124, and a branch path 125. The coolant supply path 122 connects a fluid outlet of the radiator 128 to a coolant supply port 12e of the fuel cell stack 12. The coolant discharge path 124 connects a coolant discharge port 12f of the fuel cell stack 12 to a fluid supply port of the radiator 128. The branch path 125 branches off from the coolant discharge path 124 and merges with the coolant supply path 122.

[0030] The pump 126 is provided in the coolant supply path 122. The pump 126 may also be provided in the coolant discharge path 124. The radiator 128 is a heat dissipator that dissipates heat from the coolant in the coolant flow path 120. The radiator 128 may include a fan.

[0031] The temperature sensor 130 is provided in the coolant discharge path 124. The temperature sensor 130 may be provided in the coolant supply path 122. The temperature sensor 130 detects the temperature of the coolant (coolant temperature). The coolant temperature corresponds to the temperature inside the fuel cell stack 12 (stack temperature).

[0032] The flow dividing valve 132 is provided at a junction where the branch path 125 joins the refrigerant supply path 122. The flow dividing valve 132 may also be provided at a branch point where the branch path 125 branches off from the refrigerant discharge path 124. The opening degree of the flow dividing valve 132 is adjustable. The amount of refrigerant supplied to the radiator 128 is adjusted according to the opening degree of the flow dividing valve 132.

[0033] The control device 22 may be configured by an ECU (Electronic Control Unit). The control device 22 includes a calculation unit 136 and a storage unit 138.

[0034] The calculation unit 136 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The calculation unit 136 includes a reception unit 140 and a control unit 142. The reception unit 140 receives commands from a control system that controls the vehicle. The control unit 142 performs control based on the commands received by the reception unit 140. The control unit 142 includes a power generation control unit 150 that performs power generation control, and an idle control unit 152 that performs idle control.

[0035] The reception unit 140 and the control unit 142 are operated by the calculation unit 136 executing a program stored in the storage unit 138. At least one of the reception unit 140 and the control unit 142 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). Alternatively, at least one of the reception unit 140 and the control unit 142 may be realized by an electronic circuit including a discrete device.

[0036] The storage unit 138 is a computer-readable storage medium. The storage unit 138 includes a volatile memory and a non-volatile memory. The volatile memory is, for example, a random access memory (RAM). The non-volatile memory is, for example, a read-only memory (ROM), a flash memory, etc. Data and the like are stored in, for example, the volatile memory. Programs, tables, maps, and the like are stored in, for example, the non-volatile memory. At least a part of the storage unit 138 may be provided in the above-mentioned processor, integrated circuit, etc.

[0037] [2. Fluid flow in fuel cell system 10] 2-1 Fluid flow in the anode system 16 The injector 94 injects fuel gas supplied from the tank 14 downstream of the fuel gas supply path 84. The fuel gas injected from the injector 94 is supplied to the fuel gas supply port 12a of the fuel cell stack 12 via the fuel gas supply path 84. The fuel gas that does not react inside the fuel cell stack 12 is discharged as fuel off-gas from the fuel gas discharge port 12b of the fuel cell stack 12. The fuel off-gas contains hydrogen that did not react with oxygen, nitrogen in the oxidant gas that has permeated the electrolyte membrane 36, and moisture produced by the reaction between oxygen and hydrogen.

[0038] The fuel off-gas is supplied to a gas-liquid separator 98 via a fuel gas discharge path 86. The gas-liquid separator 98 separates the fuel off-gas into a gas component (fuel off-gas) and a liquid component (water). The fuel off-gas discharged from the gas-liquid separator 98 is supplied to an ejector 96 via a circulation path 88. The fuel off-gas sucked from the gas-liquid separator 98 and the fuel gas injected from the injector 94 join together in the ejector 96.

[0039] [2-2 Fluid flow in the cathode system 18] The compressor 112 discharges oxidant gas (air) taken in from outside the vehicle downstream of the oxidant gas supply channel 106. The oxidant gas discharged from the compressor 112 is supplied to the oxidant gas supply port 12c of the fuel cell stack 12 via the oxidant gas supply channel 106. The oxidant gas that has not reacted inside the fuel cell stack 12 is discharged as oxidant off-gas from the oxidant gas discharge port 12d of the fuel cell stack 12. The oxidant off-gas contains each component contained in the oxidant gas and moisture produced by the reaction of oxygen and hydrogen.

[0040] The oxidant off-gas is discharged to the diluter 121 via the oxidant gas discharge path 108. The oxidant off-gas contains moisture. In the humidifier 114, a portion of the moisture contained in the oxidant off-gas is used to humidify the oxidant gas flowing through the humidifier supply path 114A.

[0041] 2-3 Fluid flow in the cooling system 20 The pump 126 discharges the coolant toward the coolant supply port 12e of the fuel cell stack 12. The coolant discharged from the pump 126 is supplied to the coolant supply port 12e of the fuel cell stack 12 via the coolant supply path 122. The coolant that has circulated inside the fuel cell stack 12 is discharged from the coolant discharge port 12f of the fuel cell stack 12. The coolant discharged from the coolant discharge port 12f is supplied to the radiator 128 via the coolant discharge path 124. The coolant that has dissipated heat in the radiator 128 reaches the pump 126.

[0042] A portion of the refrigerant discharged from the refrigerant discharge port 12f is not supplied to the radiator 128, but flows into the refrigerant supply path 122 via the branch path 125. The amount of this inflow is adjusted according to the opening of the branch valve 132.

[0043] [3 Power generation control] The power generation control unit 150 controls the operation of the injector 94, the compressor 112, the pump 126, the valves, etc., to cause the power generation cell 28 to generate power.

[0044] More specifically, when the receiving unit 140 receives a system start command, which is a command to start the fuel cell system 10, the power generation control unit 150 opens the first shut-off valve 116 and the second shut-off valve 118. Thereafter, the power generation control unit 150 controls the injector 94, the compressor 112, and the bypass valve 119 so that the power generated by the power generating cell 28 becomes the requested power generation power. The requested power generation power is calculated by the power generation control unit 150 based on, for example, the accelerator opening, the vehicle speed, the road gradient, etc. When the receiving unit 140 receives a system stop command, which is a command to stop the fuel cell system 10, the power generation control unit 150 closes the first shut-off valve 116 and the second shut-off valve 118. The power generation control unit 150 also stops the injector 94 and the compressor 112.

[0045] The system start command is supplied when the switch (start switch) of the fuel cell system 10 is turned on. The system stop command is supplied when the switch of the fuel cell system 10 is turned off. The switch of the fuel cell system 10 corresponds to the ignition switch of a vehicle.

[0046] [4 Idle Control] When the receiving unit 140 receives a power generation stop command while the vehicle is running with the ignition switch on, the idle control unit 152 executes idle control. The power generation stop command is a command to stop power generation by the power generation cell 28 while the fuel cell system 10 is operating. Figure 2 is a diagram showing the fuel cell system 10 when idle control is executed.

[0047] During idle control, the idle control unit 152 closes the first shut-off valve 116 and the second shut-off valve 118 without stopping the compressor 112 or closing the bypass valve 119. Therefore, the oxidant gas output from the compressor 112 to the oxidant gas supply channel 106 is not supplied to the fuel cell stack 12, but flows into the oxidant gas discharge channel 108 via the bypass channel 110. As a result, power generation by the power generation cell 28 is stopped while the fuel cell system 10 is operating. Note that during idle control, the idle control unit 152 continues to supply fuel gas to the fuel gas supply channel 84 without stopping the injector 94. This prevents a relatively high voltage from being generated between the anode electrode 38 and the cathode electrode 40.

[0048] In idle control, the opening of bypass valve 119 and the rotation speed of compressor 112 are set to predetermined values. That is, idle control unit 152 sets the opening of bypass valve 119 to a first opening that is smaller than the maximum opening. Furthermore, idle control unit 152 sets the rotation speed of compressor 112 to a predetermined rotation speed that is lower than the rotation speed during power generation. More specifically, idle control unit 152 sets the rotation speed of compressor 112 lower than the rotation speed corresponding to the upper limit of the noise level allowed in compressor 112 (noise generation upper limit rotation speed). Note that the predetermined rotation speed may be the lowest rotation speed at which compressor 112 can rotate in a stable state.

[0049] When the receiving unit 140 receives a power consumption command requesting consumption of power stored in the battery 26A during idle control, the idle control unit 152 changes the settings of the opening of the bypass valve 119 and the rotation speed of the compressor 112. More specifically, the idle control unit 152 changes the setting of the opening of the bypass valve 119 from the first opening to a second opening that is greater than the first opening. The second opening may be the maximum opening. The idle control unit 152 also changes the setting of the rotation speed of the compressor 112 from the predetermined rotation speed to a rotation speed that is greater than the predetermined rotation speed. The power consumption command is supplied when the remaining capacity stored in the battery 26A is equal to or greater than a predetermined remaining capacity threshold.

[0050] Fig. 3 is a flowchart showing the procedure of the idle control process. Fig. 4 is a time chart showing the behavior of the fuel cell system 10 during the idle control process. The idle control process proceeds to step S2 when the reception unit 140 receives a power generation stop command in step S1.

[0051] In step S2, the idle control section 152 closes the first shut-off valve 116 and the second shut-off valve 118. When the first shut-off valve 116 and the second shut-off valve 118 are closed, the idle control process proceeds to step S3.

[0052] In step S3, idle control section 152 sets the opening degree of bypass valve 119 to a first opening degree. Once the opening degree of bypass valve 119 is set, the idle control process proceeds to step S4.

[0053] In step S4, the idle control unit 152 sets the rotation speed of the compressor 112 to a predetermined rotation speed that is lower than the rotation speed during power generation. The predetermined rotation speed is lower than the rotation speed corresponding to the upper limit of the noise level allowable in the compressor 112 (noise generation upper limit rotation speed). Therefore, the flow rate of the oxidant gas output from the compressor 112 to the oxidant gas supply channel 106 is less than the flow rate (noise generation upper limit flow rate) LFR corresponding to the upper limit of the noise level allowable in the compressor 112 (see FIG. 4). Once the rotation speed of the compressor 112 is set, the idle control process proceeds to step S5.

[0054] In step S5, idle control unit 152 determines whether or not a power consumption command has been received by reception unit 140. If reception unit 140 has not received a power consumption command, the idle control process remains at step S5. On the other hand, if reception unit 140 has received a power consumption command, the idle control process proceeds to step S6.

[0055] In step S6, the idle control unit 152 changes the setting of the opening of the bypass valve 119 from the first opening set in step S2 to a second opening. The idle control unit 152 also changes the setting of the rotation speed of the compressor 112 from the predetermined rotation speed set in step S4 to a rotation speed higher than the predetermined rotation speed. This increases the flow rate of the oxidant gas output from the compressor 112 to the oxidant gas supply channel 106 (see FIG. 4). This increases the amount of power consumed by the compressor 112. After the settings of the opening of the bypass valve 119 and the rotation speed of the compressor 112 are changed, the idle control process proceeds to step S7.

[0056] In step S7, idle control unit 152 determines whether the supply of the power generation stop command is continuing. If reception unit 140 continues to receive the power generation stop command, idle control unit 152 determines that the supply of the power generation stop command is continuing. In this case, the idle control process remains at step S7. If reception unit 140 has not received the power generation stop command, idle control unit 152 determines that the supply of the power generation stop command is not continuing. In this case, the idle control process ends.

[0057] [5. Effects of the above embodiment] When the control device 22 receives a power generation stop command while the vehicle is in operation (while the vehicle is driving), it sets the rotation speed of the compressor 112 to a predetermined rotation speed that is lower than the rotation speed during power generation.

[0058] At this time, the control device 22 closes the first shut-off valve 116 and the second shut-off valve 118 without closing the bypass valve 119. However, when the bypass valve 119 is at its maximum opening, pressure loss is low, and therefore the oxidant gas can easily flow even if the rotation speed of the compressor 112 is set low. As a result, noise may be generated from the compressor 112. In response to this, the control device 22 of this embodiment sets the opening of the bypass valve 119 to a first opening that is smaller than the maximum opening. This makes it possible to effectively reduce noise generated from the compressor 112 compared to when the bypass valve 119 is at its maximum opening. In addition, the startup time of the compressor 112 can be shortened.

[0059] Increasing the rotation speed of the compressor 112 even when the oxidant gas is in a state where it is relatively difficult to flow therethrough may result in damage to the compressor 112. In response to this, when the control device 22 of this embodiment receives a power consumption command, it changes the setting of the opening of the bypass valve 119 to a second opening that is greater than the first opening. Furthermore, when the control device 22 receives a power consumption command, it changes the setting of the rotation speed of the compressor 112 to a rotation speed that is greater than a predetermined rotation speed. This allows the compressor 112 to consume power while suppressing damage to the compressor 112.

[0060] [6 Modifications of the above embodiment] The above embodiment may be modified as follows.

[0061] (Variation 1) In this modification, the power consumption command specifies the amount of power to be consumed from battery 26A. In this modification, in step S5 above, idle control unit 152 changes the setting of the opening degree (second opening degree) of bypass valve 119 according to the amount of power specified by the power consumption command. In this case, the opening degree (second opening degree) of bypass valve 119 is set to be larger as the amount of power specified by the power consumption command is larger. According to this modification, damage to compressor 112 can be suppressed.

[0062] (Variation 2) In this modification, the power consumption command specifies the amount of power to be consumed from battery 26A. In this modification, in step S5 above, idle control unit 152 changes the setting of the rotation speed of compressor 112 according to the amount of power specified by the power consumption command. In this case, the rotation speed of compressor 112 is set to be higher as the amount of power specified by the power consumption command is larger. According to this modification, it is possible to consume the power of battery 26A in a generally constant period of time regardless of the amount of power specified by the power consumption command. Note that this modification may be combined with modification 1 above.

[0063] (Variation 3) It is not necessary to provide either the first sealing valve 116 or the second sealing valve 118. Even in this case, the same effects as those of the above embodiment can be obtained.

[0064] [7 Notes] In addition to the above disclosure, the following additional notes are also disclosed.

[0065] (Appendix 1) The present disclosure relates to a fuel cell stack (12) including a power generation cell (28), a battery (26A) that stores power generated by the power generation cell, an oxidant gas supply channel (106) connected to the fuel cell stack, an oxidant gas discharge channel (108) connected to the fuel cell stack, a bypass channel (110) having one end connected to the oxidant gas supply channel and the other end connected to the oxidant gas discharge channel, a compressor (112) that supplies oxidant gas to the oxidant gas supply channel, and a connection part (CP1) to which the one end of the bypass channel is connected and the fuel cell stack, and a connection part (CP2) to which the other end of the bypass channel is connected and the fuel cell stack. A control device (22) is provided in a fuel cell system (10) having one or more sealing valves (116, 118) provided in at least one of the gas discharge paths and a bypass valve (119) provided in the bypass path and having an adjustable opening, the control device (22) comprising: a receiving unit (140) that receives a command; and a control unit (142) that performs control based on the command, wherein when the receiving unit receives a power generation stop command to stop power generation of the power generation cell while maintaining the operating state of the fuel cell system, the control unit closes the sealing valve and sets the opening of the bypass valve to a first opening that is smaller than the maximum opening, and sets the rotational speed of the compressor to a predetermined rotational speed that is lower than the rotational speed during power generation of the power generation cell.

[0066] When the sealing valve is closed and the compressor rotation speed is set to a predetermined rotation speed lower than the rotation speed during power generation, the pressure loss is reduced if the bypass valve is at its maximum opening. Therefore, even if the compressor rotation speed is set low, the oxidant gas flows easily, which can lead to noise generation from the compressor. In the present disclosure, the bypass valve is set to a first opening smaller than the maximum opening. This effectively reduces noise generated from the compressor compared to when the bypass valve is at its maximum opening.

[0067] (Appendix 2) In the control device described in Supplementary Note 1, when the opening of the bypass valve is set to the first opening and the rotation speed of the compressor is set to the predetermined rotation speed, if the receiving unit receives a power consumption command to request consumption of power stored in the battery, the control unit may change the setting of the opening of the bypass valve to a second opening that is larger than the first opening and change the setting of the rotation speed to the rotation speed that is larger than the predetermined rotation speed.

[0068] As a result, even if a power consumption command is received when the power generation of the power generation cell is stopped while the fuel cell system is operating, the compressor can consume power while minimizing damage to the compressor.

[0069] (Appendix 3) In the control device according to Supplementary Note 1, the predetermined rotation speed may be lower than the rotation speed corresponding to an upper limit of a noise level allowed in the compressor.

[0070] This effectively reduces the noise generated by the compressor.

[0071] (Appendix 4) In the control device described in Supplementary Note 2, the control unit may change a setting of an opening degree of the bypass valve in accordance with an amount of power specified by the power consumption command.

[0072] According to the above, damage to the compressor 112 can be suppressed.

[0073] (Appendix 5) In the control device described in Supplementary Note 2, the control unit may change the setting of the rotation speed in accordance with the amount of power specified by the power consumption command.

[0074] Based on the above, it is possible to consume the battery power in a generally constant period regardless of the amount of power specified by the power consumption command.

[0075] (Appendix 6) The present disclosure is a fuel cell system including the control device according to any one of Supplementary Notes 1 to 5.

[0076] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0077] 10...Fuel cell system 12...Fuel cell stack 20...Cooling system 22...Control device 26A...Battery 28...Power generating cell 106...oxidant gas supply channel 108...oxidant gas discharge channel 110...Bypass path 112...Compressor 116...First sealing valve 118...Second sealing valve 119...Bypass valve 140...Reception unit 142...control unit 150...power generation control unit 152...Idle control unit

Claims

1. a fuel cell stack including a power generation cell; a battery that stores the power generated by the power generating cell; an oxidant gas supply channel connected to the fuel cell stack; an oxidant gas discharge channel connected to the fuel cell stack; a bypass passage having one end connected to the oxidant gas supply passage and the other end connected to the oxidant gas discharge passage; a compressor for supplying an oxidant gas to the oxidant gas supply channel; one or more sealing valves provided in at least one of the oxidant gas supply path between the fuel cell stack and a connection portion to which the one end of the bypass path is connected and the oxidant gas discharge path between the fuel cell stack and a connection portion to which the other end of the bypass path is connected; a bypass valve provided in the bypass passage and capable of adjusting its opening degree; A control device provided in a fuel cell system having a reception unit that receives a command; a control unit that performs control based on the command; Equipped with a control device in which, when the receiving unit receives a power generation stop command to stop power generation of the power generation cell while the fuel cell system is operating, the control unit closes the sealing valve, sets the opening of the bypass valve to a first opening that is smaller than a maximum opening, and sets the rotation speed of the compressor to a predetermined rotation speed that is lower than the rotation speed during power generation of the power generation cell.

2. The control device according to claim 1, a control device wherein, when the reception unit receives a power consumption command for requesting consumption of power stored in the battery in a state in which the opening of the bypass valve is set to the first opening and the rotational speed of the compressor is set to the predetermined rotational speed, the control unit changes the setting of the opening of the bypass valve to a second opening that is larger than the first opening and changes the setting of the rotational speed to the rotational speed that is larger than the predetermined rotational speed.

3. The control device according to claim 1, The control device, wherein the predetermined rotation speed is lower than the rotation speed corresponding to an upper limit of a noise level allowed in the compressor.

4. The control device according to claim 2, The control unit changes the setting of the opening degree of the bypass valve in accordance with the amount of power specified by the power consumption command.

5. The control device according to claim 2, The control unit changes the setting of the rotation speed in accordance with the amount of power specified by the power consumption command.

6. A fuel cell system comprising the control device according to any one of claims 1 to 5.

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