fuel cell system

Abstract

This invention relates to a fuel cell system. When the fuel cell stack (18) starts generating electricity, the fuel cell system (10) performs a first valve driving action, which causes the power supply unit (200) to output a first voltage to drive the electric valve (202) in the opening direction. If the electric valve (202) is still in the closed state even though the first valve driving action has been performed, the fuel cell system (10) performs a second valve driving action, which causes the power supply unit (200) to output a second voltage to drive the electric valve (202) in the opening direction.

Description

Technical Field

[0001] This invention relates to a fuel cell system mounted on a mobile body or the like. Background Technology

[0002] In recent years, fuel cells have attracted attention in various fields. For example, there are fuel cell vehicles equipped with fuel cells. Fuel cell vehicles use electricity generated through electrochemical reactions in the fuel cell to drive an electric motor, thus propelling the vehicle. Therefore, unlike gasoline vehicles, they do not emit CO2, NOx, SOx, etc., but only water, making them environmentally friendly. Besides automobiles, fuel cells can also be used in other mobile bodies such as ships, aircraft, and robots.

[0003] Various valves are used in fuel cell systems used to generate electricity from fuel cells. When using fuel cell systems in cold regions, valves may freeze and become fixed. Patent Document 1 discloses a method to release the frozen state of a valve by alternately generating torque in the direction of increasing valve opening and torque in the direction of decreasing valve opening.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-16741 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, if the frozen state is firmly established, the method in Patent Document 1 may not be able to remove the frozen state. In this case, it is believed that applying a strong torque to the valve can remove the frozen state.

[0009] When applying high torque to the valve, the drive voltage used to actuate the valve needs to be increased. Therefore, there is a concern that this could accelerate power supply degradation. Consequently, it is desirable to suppress this degradation and remove any lag.

[0010] The purpose of this invention is to solve the above-mentioned problems.

[0011] Solution for solving the problem

[0012] To achieve the above objectives, a fuel cell system according to one aspect of the present invention includes: a fuel cell stack that generates electricity through an electrochemical reaction between fuel gas and oxidant gas; an oxidant supply path that supplies the oxidant gas to the fuel cell stack; and an electric valve disposed in the oxidant supply path. The fuel cell system further includes: a power supply device that outputs one of a first voltage and a second voltage to the electric valve, wherein the second voltage is higher than the first voltage; a sensor that detects the open / closed state of the electric valve; and a control device that controls the power supply device. When the fuel cell stack starts generating electricity, the control device performs a first valve-driving action that causes the power supply device to output the first voltage to drive the electric valve in the opening direction. If, even after performing the first valve-driving action, the electric valve remains in the closed state, the control device performs a second valve-driving action that causes the power supply device to output the second voltage to drive the electric valve in the opening direction.

[0013] The effects of the invention

[0014] According to one aspect of the present invention, compared to the case where the first valve actuation is not performed, the promotion of power supply degradation can be suppressed, and the power consumption of the electric valve can be reduced. Furthermore, by performing the second valve actuation, even if the electric valve is in a relatively strong frozen state, the frozen state can be released. As a result, the promotion of power supply degradation can be suppressed, and the frozen state can be released.

[0015] The above-described objects, features, and advantages can be readily understood from the following description of the embodiments, which are illustrated with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the structure of a fuel cell system according to an embodiment.

[0017] Figure 2 This is a block diagram showing a portion of the structure of a fuel cell system.

[0018] Figure 3 This is a flowchart illustrating the sequence of valve control processes.

[0019] Figure 4 This is a timing diagram showing the timing of the action of the control device that performs the valve control process. Detailed Implementation

[0020] Figure 1 This is a schematic diagram showing the structure of a fuel cell system 10 according to an embodiment. The fuel cell system 10 includes a fuel cell stack (also simply referred to as a fuel cell) 18, a hydrogen tank 20, an oxidant gas supply device 22, and a fuel gas supply device 24.

[0021] The fuel cell stack 18 generates electricity through an electrochemical reaction between fuel gas and oxidant gas. Examples of fuel gas include hydrogen. Examples of oxidant gas include air containing oxygen.

[0022] Multiple power-generating cells 50 are stacked in 18 layers in the fuel cell stack. Each power-generating cell 50 has an electrolyte membrane-electrode structure 52 and spacers 53 and 54 that hold the electrolyte membrane-electrode structure 52.

[0023] The electrolyte membrane-electrode structure 52 includes: a solid polymer electrolyte membrane 55, for example, a thin film of perfluorosulfonic acid containing water; and a cathode electrode 56 and an anode electrode 57 that hold the solid polymer electrolyte membrane 55.

[0024] The cathode electrode 56 and the anode electrode 57 have a gas diffusion layer (not shown) formed of carbon paper or the like. Porous carbon particles with platinum alloy on their surface are uniformly coated on the surface of the gas diffusion layer to form an electrode catalyst layer (not shown). Electrode catalyst layers are formed on both sides of the solid polymer electrolyte membrane 55.

[0025] A cathode flow path (oxidant gas flow path) 58 is formed on the side of the separator 53 facing the electrolyte membrane-electrode structure 52, which connects the oxidant gas inlet connection port 101 and the oxidant gas outlet connection port 102.

[0026] On the other side of the separator 54 facing the electrolyte membrane-electrode structure 52, an anode flow path (fuel gas flow path) 59 is formed that connects the fuel gas inlet connection port 103 and the fuel gas outlet connection port 104.

[0027] In the anode electrode 57, by supplying fuel gas (hydrogen), hydrogen ions are generated from hydrogen molecules due to an electrode reaction produced by the catalyst. These hydrogen ions move to the cathode electrode 56 through the solid polymer electrolyte membrane 55. On the other hand, electrons are released from hydrogen molecules. The electrons released from hydrogen molecules move to the cathode electrode 56 via the positive terminal.

[0028] In the cathode electrode 56, due to the action of the catalyst, the hydrogen ions, the electrons, and the oxygen contained in the supplied oxidant gas react to generate water.

[0029] Oxidant gas supply device 22 supplies oxidant gas to fuel cell stack 18. Oxidant gas supply device 22 includes compressor (CP) 28 and humidifier (HUM) 30.

[0030] The compressor 28 is composed of a mechanical booster and the like, and has the following functions: it draws in external gas (atmosphere, air) from the external gas inlet 113, pressurizes it, and supplies it to the fuel cell stack 18 through the humidifier 30.

[0031] The humidifier 30 has flow path 31A and flow path 31B. Air (oxidant gas) that has been compressed, heated and dried by the compressor 28 flows through flow path 31A. Exhaust gas discharged from the oxidant gas outlet connection 102 of the fuel cell stack 18 flows through flow path 31B.

[0032] Here, when the discharge valve 70 is closed, the discharged gas becomes a moist oxidant exhaust gas (moist cathode exhaust gas, moist oxidant emission gas), and when the discharge valve 70 is open, the moist discharge gas (exhaust gas) formed by the mixture of the moist oxidant exhaust gas and the fuel exhaust gas (anode exhaust gas, fuel emission gas) will flow.

[0033] The humidifier 30 has the function of humidifying the oxidant gas supplied from the compressor 28. That is, the humidifier 30 causes the moisture contained in the exhaust gas (exhaust gas) to move from the flow path 31B through the internal porous membrane to the supply gas (oxidant gas) flowing in the flow path 31A for humidification, and supplies the humidified oxidant gas to the fuel cell stack 18.

[0034] In the oxidant supply flow path 60 (including oxidant supply flow paths 60A and 60B) from the external gas inlet 113 to the oxidant gas inlet connection 101, a shut-off valve 114, an air flow sensor (AFS: flow sensor) 116, a compressor 28, a supply-side sealing valve 118, and a humidifier 30 are sequentially arranged from the external gas inlet 113. Moreover, the flow paths of the oxidant supply flow path 60, etc., depicted with double lines, are formed by piping (the same applies below).

[0035] The shut-off valve 114 is opened or closed to allow air to be introduced into or out of the oxidant supply path 60.

[0036] Air flow sensor 116 measures the flow rate of oxidant gas supplied to fuel cell stack 18 via compressor 28.

[0037] The supply-side sealing valve 118 opens and closes the oxidant supply path 60A.

[0038] A temperature sensor 73 is installed at the external gas inlet 113 to detect (measure) the temperature of the external gas.

[0039] In the oxidant discharge flow path 62 connected to the oxidant gas outlet 102, a humidifier 30 and a discharge side sealing valve 120, which also functions as a back pressure valve, are sequentially arranged from the oxidant gas outlet 102.

[0040] A bypass flow path 64 is provided between the inlet of the supply-side sealing valve 118 and the outlet of the discharge-side sealing valve 120, connecting the oxidant supply flow path 60 and the oxidant discharge flow path 62. The bypass flow path 64 is connected to both the oxidant supply flow path 60 and the oxidant discharge flow path 62 to bypass the fuel cell stack 18. A bypass valve 122 is provided in the bypass flow path 64 to open and close the bypass flow path 64. The bypass valve 122 adjusts the flow rate of the oxidant gas bypassing the fuel cell stack 18.

[0041] The hydrogen tank 20 is equipped with an electromagnetically actuated shut-off valve. This hydrogen tank is a container for compressing and holding high-purity hydrogen at high pressure. The fuel gas supply unit 24 supplies fuel gas from the hydrogen tank 20 to the fuel cell stack 18. The fuel gas supply unit 24 includes an injector (INJ) 32, an ejector 34, and a gas-liquid separator 36. The injector 32 can also be replaced by a pressure reducing valve.

[0042] The fuel gas ejected from the hydrogen tank 20 is supplied to the inlet of the anode flow path 59 of the fuel cell stack 18 via the fuel gas inlet connection port 103 through the injector 32 and ejector 34 provided in the fuel supply flow path 72.

[0043] The outlet of the anode flow path 59 is connected to the inlet 151 of the gas-liquid separator 36 via the fuel gas outlet connection 104 and the fuel gas discharge flow path 74. The fuel exhaust gas containing hydrogen is supplied from the anode flow path 59 to the gas-liquid separator 36.

[0044] The gas-liquid separator 36 separates the fuel exhaust gas into gaseous and liquid components (liquid water). The gaseous component of the fuel exhaust gas (fuel emission gas) is discharged from the gas outlet 152 of the gas-liquid separator 36 and supplied to the inlet of the ejector 34 through the circulation path 77. On the other hand, when the discharge valve 70 is open, the fuel exhaust gas is also supplied to the oxidant supply path 60B through the connecting path 78 and the discharge valve 70.

[0045] The liquid component of the fuel exhaust gas is supplied from the liquid outlet 160 of the gas-liquid separator 36 through the drain flow path 162 to the confluence section MP, which merges with the oxidant discharge flow path 62. The confluence section MP is connected to the discharge flow path 99. The discharge flow path 99 discharges the oxidant exhaust gas supplied from the oxidant discharge flow path 62 and the fuel exhaust gas supplied from the drain flow path 162 to the outside through the exhaust gas outlet 168.

[0046] In practice, a portion of the fuel exhaust (containing hydrogen gas) is discharged into the exhaust path 162 along with the liquid components. To dilute the hydrogen in the fuel exhaust and discharge it to the outside, a portion of the oxidant gas injected from the compressor 28 is supplied to the confluence section MP through the bypass path 64.

[0047] The opening and closing of the discharge valve 70 installed in the connecting flow path 78 that connects the fuel exhaust circulation flow path 77 and the oxidant supply flow path 60B is controlled based on either of the two reasons described below.

[0048] First, during the movement of the mobile body equipped with the fuel cell system 10, in order to prevent the hydrogen concentration in the anode flow path 59 from decreasing due to the nitrogen gas present in the cathode flow path 58 passing through the electrolyte membrane-electrode structure 52, which would lead to the deterioration of the anode electrode 57, the discharge valve 70 is opened (the first valve of the discharge valve 70 is continuously opened and closed during the movement).

[0049] Second, when the fuel cell stack 18 is in an idle state, in order to reduce the hydrogen concentration in the exhaust gas discharged from the exhaust port 168 to the outside, the discharge valve 70 is opened (the second valve of the discharge valve 70 in the idle state is continuously opened and closed for control).

[0050] When the discharge valve 70 is opened, the fuel exhaust gas ejected from the fuel cell stack 18 through the fuel discharge path 74 and the gas-liquid separator 36 flows through the connecting path 78, the oxidant supply path 60B and the oxidant gas inlet connection 101 to the cathode path 58.

[0051] The fuel gas in the fuel exhaust flowing into the cathode flow path 58 is ionized with hydrogen by the catalyst reaction in the cathode electrode 56. The hydrogen ions react with the oxidant gas to produce water. The unreacted remaining fuel exhaust (including nitrogen and a small amount of unreacted hydrogen) is discharged from the fuel cell stack 18 as oxidant exhaust and flows into the oxidant exhaust flow path 62.

[0052] The oxidant exhaust gas (including the unreacted remaining portion of the fuel exhaust gas) flowing to the oxidant discharge path 62 is mixed with the oxidant gas supplied through the bypass path 64, and the oxidant exhaust gas with the concentration of fuel exhaust gas (including fuel gas) in the oxidant exhaust gas flows to the confluence section MP.

[0053] In the discharge flow path 99 connected to the confluence section MP, the fuel gas in the mixture of liquid water sprayed from the discharge flow path 162 and fuel exhaust gas is diluted by the oxidant exhaust gas from the oxidant discharge flow path 62 and discharged to the outside (atmosphere) through the exhaust gas port 168.

[0054] Furthermore, the valve used is a discharge valve 70 with an opening diameter larger than that of the discharge valve 164 installed in the discharge flow path 162. Due to this opening diameter, even if the discharge valve 164 remains open due to freezing or other reasons, the amount of fuel exhaust flowing into the connecting flow path 78 is greater than the amount of fuel exhaust flowing into the discharge valve 164. As a result, the concentration of fuel gas discharged from the exhaust port 168 can be reduced.

[0055] Figure 2 This is a block diagram showing a portion of the structure of the fuel cell system 10. In addition to the structural elements described above, the fuel cell system 10 also includes a power supply unit 200, an electric valve 202, a sensor 204, and a control unit 206.

[0056] The power supply unit 200, under the control of the control unit 206, outputs one of a first voltage and a second voltage to the electric valve 202. The second voltage is a voltage higher than the first voltage. Furthermore, both the first and second voltages are DC voltages. The power supply unit 200 includes a power supply section 208 and a boost section 210.

[0057] The power supply unit 208 outputs a first voltage to the boost unit 210. Alternatively, the power supply unit 208 may be a battery that stores electricity generated by the fuel cell stack 18. The boost unit 210 may be configured as a DC-DC converter or the like. The boost unit 210 outputs either a first voltage or a second voltage to the electric valve 202 depending on whether there is a boost requirement from the control device 206.

[0058] When there is no boosting requirement from control device 206, boost unit 210 does not boost the first voltage supplied from power supply unit 208, but outputs the first voltage to electric valve 202. When there is a boosting requirement from control device 206, boost unit 210 boosts the first voltage supplied from power supply unit 208 and outputs the second voltage obtained by boosting to electric valve 202. When boost unit 210 is a DC-DC converter, boost unit 210 generates the second voltage according to the switching control performed by control device 206.

[0059] In this embodiment, the electric valve 202 is a supply-side sealing valve 118 provided in the oxidant supply flow path 60A. The electric valve 202 has a valve body and a motor. The valve body is opened or closed by controlling the motor through the control device 206.

[0060] Sensor 204 detects the open / closed state of electric valve 202. Sensor 204 outputs a detection signal indicating whether electric valve 202 is in an open or closed state. Sensor 204 can also be a flow sensor. For example, the flow sensor measures the flow rate of oxidant gas flowing between electric valve 202 (supply-side sealing valve 118) and humidifier 30 in the oxidant supply path 60. When the oxidant gas flow rate is above a predetermined flow threshold, the flow sensor outputs a detection signal indicating that electric valve 202 is in an open state to control device 206. Conversely, when the oxidant gas flow rate is below the predetermined flow threshold, the flow sensor outputs a detection signal indicating that electric valve 202 is in a closed state to control device 206.

[0061] The control device 206 provides comprehensive control over the fuel cell system 10. The control device 206 comprises a computer with one or more processors (CPUs), memory, input / output interfaces, and circuitry. The one or more processors (CPUs) execute programs (not shown) stored in the memory.

[0062] The processor (CPU) of the control device 206 performs calculations according to the program, thereby controlling the operation of the fuel cell system 10.

[0063] That is, when the control device 206 receives a command to start the power generation of the fuel cell stack 18, it opens the shut-off valve of the hydrogen tank 20 to supply fuel gas to the fuel cell stack 18. Then, when the start-up timing of the electric valve 202 (supply-side sealing valve 118) is reached, the control device 206 performs valve control processing to control the electric valve 202.

[0064] Figure 3 This is a flowchart illustrating the sequence of valve control processes.

[0065] In step S1, the control device 206 performs a valve-driving action (first valve-driving action or second valve-driving action) to drive the electric valve 202. Immediately after the start-up timing of the electric valve 202, the control device 206 performs the first valve-driving action. In this case, the control device 206 does not output a boosting request to the boosting unit 210, but begins to output an opening instruction to the electric valve 202. That is, the control device 206 causes the power supply device 200 to output a first voltage, driving the electric valve 202 in the opening direction, and proceeds to step S2.

[0066] In step S2, after a predetermined period has elapsed since the valve opening instruction was output to the electric valve 202, the control device 206 confirms the opening and closing status of the electric valve 202 based on the detection signal output from the sensor 204.

[0067] Here, when the detection signal indicates that the electric valve 202 is in the open state, the control device 206 terminates the valve control process. In this case, the control device 206 maintains the electric valve 202 in the open state while causing the fuel cell stack 18 to perform power generation. That is, the control device 206 supplies drive power to the compressor 28 to drive the compressor 28. In addition, the control device 206 controls the discharge side sealing valve 120 to be in the open state. Furthermore, the control device 206 determines the target power generation based on at least one of the temperature, voltage, and power generation of the fuel cell stack 18, and adjusts the opening degree of the bypass valve 122 according to the target power generation. In addition, the control device 206 switches the drain valve 164 to either the open or closed state based on the water level sensor in the gas-liquid separator 36, etc., to keep the amount of liquid component in the gas-liquid separator 36 constant.

[0068] On the other hand, when the detection signal indicates that the electric valve 202 is in the closed state, the control device 206 stops outputting the valve opening instruction to the electric valve 202. Then, the control device 206 proceeds to step S3.

[0069] In step S3, the control device 206 determines whether the valve actuation action has been performed a predetermined number of times. If the predetermined number of valve actuation actions has not been performed, the control device 206 returns to step S1. Conversely, if the predetermined number of valve actuation actions has been performed, the control device 206 proceeds to step S4.

[0070] In step S4, the control device 206 determines whether the second valve actuation action has been performed. If the second valve actuation action has not been performed, the control device 206 proceeds to step S5, begins to output a boost demand to the boost unit 210, and then returns to step S1. In this case, in step S1, the control device 206 performs the second valve actuation action. That is, the control device 206 causes the power supply device 200 to output a second voltage, driving the electric valve 202 in the opening direction.

[0071] On the other hand, upon performing the second valve actuation, the control device 206 proceeds to step S6, and after stopping the voltage output (first voltage and second voltage) to the electric valve 202, terminates the valve control process. In this case, the control device 206 stops the power generation operation of the fuel cell stack 18. That is, the control device 206 closes the shut-off valve of the hydrogen tank 20, stopping the supply of fuel gas to the fuel cell stack 18.

[0072] Thus, the control device 206 will perform the first valve actuation a predetermined number of times until the electric valve 202 is in the open state. If the electric valve 202 remains in the closed state even after the predetermined number of first valve actuations have been performed, the control device 206 will perform the second valve actuation a predetermined number of times until the electric valve 202 is in the open state.

[0073] Figure 4 This is a timing diagram showing the operation timing of the control device 206 that performs the valve control processing. Figure 4 The example shown is when the valve actuation action is performed once. Additionally, in... Figure 4 The diagram shows an example where the electric valve 202 is not opened by the first valve actuation but is opened by the second valve actuation.

[0074] When the control device 206 initiates valve control processing, it does not output a pressure boosting request to the pressure boosting unit 210, but instead begins to output a valve opening instruction to the electric valve 202. Figure 4 In this case, when the control device 206 outputs an opening instruction to the electric valve 202, it sets the status signal to "operating". Figure 4 (T2). The status signal is a signal indicating the status of the electric valve 202.

[0075] If, even after a predetermined output holding time has elapsed since the start of the valve opening instruction to the electric valve 202, the electric valve 202 is not detected to be in the open state, the control device 206 stops outputting the valve opening instruction to the electric valve 202. Figure 4 (T3). In this case, the control device 206 changes the status signal from "operating" to "failed" when the timing for stopping the output of the valve opening instruction to the electric valve 202 is stopped. Figure 4 (T4). Additionally, when the control device 206 stops outputting the valve opening instruction to the electric valve 202, it outputs a pressure boosting request to the pressure boosting unit 210. Figure 4 :T5).

[0076] When a predetermined output stop time has elapsed since the output of the valve opening instruction to the electric valve 202 was stopped, the control device 206 starts outputting the valve opening instruction to the electric valve 202 again. Figure 4 (T6). In this case, when the control device 206 resumes outputting the valve opening instruction, it changes the status signal from "failure" to "operating". Figure 4 :T7).

[0077] Subsequently, when the electric valve 202 is detected to be in the open state, the control device 206 stops outputting the pressure boosting request to the pressure boosting unit 210. Figure 4(T8). In this case, the control device 206 changes the status signal from "operating" to "successful" when the timing for stopping the output of the boost request to the boost unit 210 is stopped. Figure 4 :T9).

[0078] Thus, the control device 206 performs a first valve actuation action, causing the power supply device 200 to output a first voltage to drive the electric valve 202 in the opening direction. If the electric valve 202 remains in the closed state even after the first valve actuation action is performed, the control device 206 performs a second valve actuation action, causing the power supply device 200 to output a second voltage higher than the first voltage to drive the electric valve 202 in the opening direction.

[0079] Therefore, compared to the case where the first valve actuation is not performed, the degradation of the power supply unit 200 can be suppressed, and the power consumption of the electric valve 202 can be reduced. Furthermore, by performing the second valve actuation, even if the electric valve 202 is in a relatively frozen state, the freeze can be lifted.

[0080] The present invention is not particularly limited to the embodiments described above, and various modifications can be made without departing from its spirit.

[0081] For example, the control device 206 may determine whether the electric valve 202 is frozen based on the temperature sensor 73. For instance, if the external gas temperature exceeds a predetermined temperature threshold, the control device 206 determines that the electric valve 202 is not frozen. In this case, the control device 206 performs a second valve actuation after performing the first valve actuation, as described in the above embodiment. On the other hand, if the external gas temperature is below the predetermined temperature threshold, the control device 206 determines that the electric valve 202 is frozen. In this case, the control device 206 may perform the second valve actuation instead of the first valve actuation.

[0082] Hereinafter, the invention and effects that can be grasped from the above embodiments and variations will be described. Furthermore, for ease of understanding, some structural elements are labeled with the reference numerals used in the above embodiments and variations, but the structural elements are not limited to the components labeled with these reference numerals.

[0083] (1) The present invention is a fuel cell system comprising: a fuel cell stack 18, which generates electricity through an electrochemical reaction between fuel gas and oxidant gas; an oxidant supply flow path 60, which supplies the oxidant gas to the fuel cell stack; and electric valves 202 and 118 disposed in the oxidant supply flow path. In the fuel cell system 10, there is a power supply device 200 that outputs one of a first voltage and a second voltage to the electric valve, wherein the second voltage is higher than the first voltage; a sensor 204 that detects the opening and closing state of the electric valve; and a control device 206 that controls the power supply device. When the fuel cell stack starts generating electricity, the control device performs a first valve driving action to drive the electric valve in the opening direction by outputting the first voltage from the power supply device. If the electric valve is still in the closed state even after the first valve driving action is performed, the control device performs a second valve driving action to drive the electric valve in the opening direction by outputting the second voltage from the power supply device.

[0084] Therefore, compared to not performing the first valve actuation, the promotion of power supply degradation can be suppressed, and the power consumption of the electric valve can be reduced. Furthermore, by performing the second valve actuation, even if the electric valve is in a relatively strong frozen state, the frozen state can be released. As a result, the promotion of power supply degradation can be suppressed, and the frozen state can be eliminated.

[0085] (2) In a fuel cell system, the first valve actuation is performed a predetermined number of times. If the electric valve remains closed even after the predetermined number of first valve actuations, the control device performs the second valve actuation until the electric valve opens. Thus, compared to not performing the first valve actuation a predetermined number of times, the frozen state of the electric valve can be easily released even without performing the second valve actuation.

[0086] (3) In this invention, which is a fuel cell system, the control device may also perform the second valve actuation a predetermined number of times until the electric valve is in the open state. Therefore, compared to not performing the second valve actuation a predetermined number of times, it is easier to release the frozen state of the electric valve.

[0087] (4) The present invention relates to a fuel cell system. Alternatively, even if the second valve actuation is performed but the electric valve remains closed, the control device stops the power generation of the fuel cell stack. Thus, when oxidant gas is not supplied to the fuel cell stack via the oxidant supply path because the electric valve is closed, power generation by the fuel cell stack can be suppressed, thereby reliably maintaining safety.

Claims

1. A fuel cell system comprising: a fuel cell stack (18) that generates electricity through an electrochemical reaction of fuel gas and oxidant gas; an oxidant supply path (60) that supplies the oxidant gas to the fuel cell stack from an external gas inlet (113); and an electric valve (202) disposed in the oxidant supply path, wherein the fuel cell system (10) includes: A power supply device (200) outputs one of a first voltage and a second voltage to the electric valve, wherein the second voltage is higher than the first voltage; Temperature sensor (73), which is disposed at the external gas inlet, detects the temperature of the external gas; and Control device (206), which controls the power supply device, When the fuel cell stack starts generating electricity, if the external gas temperature exceeds a predetermined temperature threshold, the control device performs a first valve driving action to drive the electric valve in the opening direction by outputting the first voltage from the power supply device. If the external gas temperature is below the predetermined temperature threshold, the control device does not perform the first valve driving action but performs a second valve driving action to drive the electric valve in the opening direction by outputting the second voltage from the power supply device.

2. The fuel cell system according to claim 1, characterized in that, The first valve actuation is performed a predetermined number of times. If the electric valve remains closed even after the predetermined number of first valve actuation actions have been performed, the control device performs the second valve actuation until the electric valve becomes open.

3. The fuel cell system according to claim 1, characterized in that, The control device will perform the second valve driving action a predetermined number of times until the electric valve is in the open state.

4. The fuel cell system according to claim 1, characterized in that, Even if the second valve actuation is performed but the electric valve remains closed, the control device stops the power generation from the fuel cell stack.

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