Fuel cell module

Abstract

To suppress fluctuations in a fuel cell voltage when a fuel cell is generating power intermittently.SOLUTION: A fuel cell module 1 is configured to include a fuel cell FC, an injector INJ, an air compressor ACP, a sensor S that detects a rotation angle θ of a motor M, an inverter INV that drives the motor M, and a control unit 3 that controls the operation of the injector INJ and the inverter INV. When the fuel cell FC is generating intermittent power, the control unit 3 outputs a rotation command and a stop rotation angle θth to the inverter INV. When the fuel cell FC is generating intermittent power, the inverter INV repeats driving the motor M when the rotation command and the stop rotation angle θth are input, and stopping the motor M when the rotation angle θ detected by the sensor S becomes equal to or greater than the stop rotation angle θth.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fuel cell module.

Background Art

[0002] As a fuel cell module, in order to suppress deterioration of a fuel cell due to voltage fluctuations of the fuel cell during intermittent power generation of the fuel cell, after driving a motor of an air compressor that supplies an oxidant gas to the fuel cell at a minimum rotational speed (minimum rotational speed) for a predetermined time, there is a type that repeats stopping the motor of the air compressor for a predetermined time. As a related technique, there is Patent Document 1.

[0003] However, in the above fuel cell module, since the supply amount of the oxidant gas to the fuel cell is controlled by the driving time and the stopping time of the motor, if the driving time of the motor is too short, the motor stops before the motor drives, so the stopping time of the motor becomes relatively long, and there is a risk that the voltage of the fuel cell will fall below the lower limit value assumed in advance.

[0004] By the way, as a motor of an air compressor, depending on the mechanical characteristics (structural characteristics) of the motor, there is a type in which the total supply amount of the oxidant gas from the air compressor to the fuel cell increases non-linearly as the rotation angle of the motor increases.

[0005] Therefore, in the above fuel cell module, when the total supply amount of the oxidant gas from the air compressor to the fuel cell increases non-linearly as the rotation angle of the motor increases, when the motor of the air compressor is driven at the minimum rotational speed for a predetermined time, an excessive amount of oxidant gas may be supplied from the air compressor to the fuel cell, and there is a risk that the voltage of the fuel cell will exceed the upper limit value assumed in advance.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] One aspect of the present invention is to provide a fuel cell module that can suppress fluctuations in the voltage of a fuel cell during intermittent power generation. [Means for solving the problem]

[0008] A fuel cell module in one embodiment of the present invention comprises a fuel cell that generates electricity through an electrochemical reaction between hydrogen contained in a fuel gas and oxygen contained in an oxidizing gas; an air compressor equipped with an injector that adjusts the amount of fuel gas supplied to the fuel cell; a motor that adjusts the amount of oxidizing gas supplied to the fuel cell; a sensor that detects the rotation angle of the motor; and an inverter that drives the motor; and a control unit that controls the operation of the injector and the inverter.

[0009] The control unit outputs a rotation command and a stop rotation angle to the inverter when the fuel cell is generating power intermittently.

[0010] When the fuel cell is intermittently generating power, the inverter repeatedly drives the motor when the rotation command and the stop rotation angle are input, and stops the motor when the rotation angle detected by the sensor becomes greater than or equal to the stop rotation angle.

[0011] For example, by setting the stop rotation angle as the sum of the motor rotation angle corresponding to the total amount of oxidant gas supplied to increase the fuel cell voltage from the lower limit to the upper limit, and the current rotation angle, the motor can be stopped when the fuel cell voltage exceeds the upper limit. Therefore, even if the total amount of oxidant gas supplied from the air compressor to the fuel cell increases non-linearly with increasing motor rotation angle, it is possible to prevent the fuel cell voltage from exceeding the upper limit. This suppresses fluctuations in the fuel cell voltage during intermittent power generation and reduces fuel cell degradation.

[0012] Furthermore, the air compressor may be configured to increase the total amount of oxidizer gas supplied to the fuel cell each time the rotation angle of the motor increases by a certain amount during intermittent power generation of the fuel cell, and the control unit may be configured to set the stop rotation angle to a value obtained by adding the rotation angle corresponding to the total amount of oxidizer gas supplied to raise the voltage of the fuel cell from the lower limit to the upper limit to the rotation angle detected by the sensor.

[0013] This allows the motor to be stopped when the fuel cell voltage exceeds the upper limit, even if the total amount of oxidizer gas supplied from the air compressor to the fuel cell increases non-linearly as the motor rotation angle increases. Therefore, it is possible to prevent the fuel cell voltage from exceeding the upper limit.

[0014] Furthermore, the control unit may be configured to output a stop command to the inverter when the voltage of the fuel cell exceeds an upper limit during intermittent power generation of the fuel cell, and to output a rotation command to the inverter when the voltage of the fuel cell falls below a lower limit. The inverter may also be configured to stop the motor when the stop command is input during intermittent power generation of the fuel cell, or when the rotation angle detected by the sensor exceeds the stop rotation angle.

[0015] Thus, even when it becomes impossible to obtain either the voltage of the fuel cell or the rotation angle of the motor, the voltage of the fuel cell can be varied between the upper limit value and the lower limit value using the other one.

Advantages of the Invention

[0016] According to the present invention, during the intermittent power generation of the fuel cell, fluctuations in the voltage of the fuel cell can be suppressed.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a diagram showing an example of a fuel cell module according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of the operation of the control unit. [Figure 3] FIG. 3 is a flowchart showing an example of the operation of the inverter. [Figure 4] FIG. 4 is a diagram showing an example of the correspondence relationship between the voltage of the fuel cell, the rotational speed of the motor, the rotation angle of the motor, and the total supply amount of the oxidant gas.

Embodiments for Carrying Out the Invention

[0018] The embodiments will be described in detail below based on the drawings.

[0019] FIG. 1 is a diagram showing an example of a fuel cell module according to an embodiment.

[0020] The fuel cell module 1 shown in FIG. 1 is mounted on a vehicle Ve such as an industrial vehicle like a forklift or an automobile, and supplies electric power to a load Lo or the like. Note that the load Lo is an inverter that drives a traveling motor mounted on the vehicle Ve, a cargo handling device, or the like.

[0021] Further, the fuel cell module 1 includes a fuel cell FC, a hydrogen tank HT, an injector INJ, an air compressor ACP, an air pressure regulating valve ARV, a DCDC converter CNV, a power storage device B, voltmeters SV1 and SV2, an ammeter SI, a storage unit 2, and a control unit 3.

[0022] The fuel cell FC is a fuel cell stack composed of a plurality of fuel cells connected in series with each other, and generates electricity through an electrochemical reaction between hydrogen contained in the fuel gas (hydrogen gas) and oxygen contained in the oxidant gas (air).

[0023] The hydrogen tank HT is a storage container for the fuel gas. The fuel gas stored in the hydrogen tank HT is supplied to the fuel cell FC via the injector INJ.

[0024] The injector INJ adjusts the amount (flow rate) of the fuel gas per unit time T supplied to the fuel cell FC.

[0025] The air compressor ACP is, for example, a roots-type air compressor, and includes a motor M that adjusts the supply amount of the oxidant gas to the fuel cell FC, a sensor S that detects the rotation angle (mechanical angle) θ of the motor M (rotor), and an inverter INV that drives the motor M. For example, it is assumed that the larger the rotation angle or rotation speed of the motor M, the larger the amount (flow rate) of the oxidant gas output from the air compressor ACP per unit time T. Also, it is assumed that the smaller the rotation angle or rotation speed of the motor M, the smaller the amount of the oxidant gas output from the air compressor ACP per unit time T.

[0026] The air pressure regulating valve ARV adjusts the pressure of the oxidant gas supplied to the fuel cell FC.

[0027] The DCDC converter CNV is provided between the fuel cell FC and the power storage device B, raises the voltage of the fuel cell FC, and supplies the power output from the fuel cell FC to the load Lo and the power storage device B.

[0028] Furthermore, the DC-DC converter CNV comprises an inductor L, a switch SW (such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor)), a diode D, and a capacitor C. Specifically, the anode terminal of diode D is connected to the positive terminal of the fuel cell FC via inductor L and to the negative terminal of the fuel cell FC via switch SW. The cathode terminal of diode D is connected to the positive terminal of the energy storage device B. One terminal of capacitor C is connected to the cathode terminal of diode D and the positive terminal of the energy storage device B, while the other terminal of capacitor C is connected to the negative terminal of the fuel cell FC and the negative terminal of the energy storage device B.

[0029] Energy storage device B is composed of lithium-ion capacitors and other components and is installed downstream of the DC-DC converter CNV. Power is supplied from energy storage device B to load Lo, and power is supplied from load Lo to energy storage device B. In other words, if the supplied power, which is the difference between the power output from the DC-DC converter CNV and the power supplied to auxiliary equipment such as the air compressor ACP, is greater than the required power requested by the vehicle Ve side (load Lo), then the power equivalent to the required power is supplied to load Lo, and the remaining power is supplied to energy storage device B. When power is supplied from the DC-DC converter CNV to energy storage device B, energy storage device B is charged and the charge amount Ch of energy storage device B increases. Also, if the supplied power, which is the difference between the power output from the DC-DC converter CNV and the power supplied to auxiliary equipment, is less than the required power requested by load Lo, then the supplied power is supplied to load Lo, and the remaining power is supplied from energy storage device B to load Lo. When power is supplied from energy storage device B to load Lo, energy storage device B is discharged and the charge amount Ch of energy storage device B decreases. The charge amount Ch is defined as the charge rate [%] of energy storage device B (the ratio of the remaining capacity to the full charge capacity of energy storage device B), or the open-circuit voltage [V] of energy storage device B when no current is flowing through it, or the closed-circuit voltage [V] of energy storage device B when current is flowing through it, or the integrated value [Ah] of the current flowing through energy storage device B.

[0030] The voltmeter SV1 measures the voltage of the fuel cell FC and sends the measured voltage to the control unit 3. Alternatively, the voltmeter SV1 may be configured to measure the voltage of each of the multiple fuel cell cells constituting the fuel cell FC and send each of these measured voltages to the control unit 3.

[0031] The voltmeter SV2 measures the voltage of the energy storage device B and sends the measured voltage to the control unit 3.

[0032] The ammeter SI measures the current flowing through the energy storage device B and sends the measured current to the control unit 3.

[0033] The memory unit 2 is composed of memory such as RAM (Random Access Memory) or ROM (Read Only Memory).

[0034] The control unit 3 consists of a CPU (Central Processing Unit) or a programmable device (such as an FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device)) and controls the operation of the injector INJ, the air pressure regulating valve ARV, the DC-DC converter CNV, and the inverter INV.

[0035] <Control of Injector Operation> The control unit 3 controls the operation of the injector INJ so that the pressure of the fuel gas inside the fuel cell FC remains constant during power generation or intermittent power generation by the fuel cell FC.

[0036] For example, during power generation or intermittent power generation by the fuel cell FC, the control unit 3 controls the operation of the injector INJ so that the supply of fuel gas from the hydrogen tank HT to the fuel cell FC stops when the pressure of the hydrogen electrode (anode) of the fuel cell FC exceeds a predetermined pressure, and controls the operation of the injector INJ so that the supply of fuel gas from the hydrogen tank HT to the fuel cell FC resumes when the pressure of the hydrogen electrode of the fuel cell FC falls below the predetermined pressure.

[0037] <Air pressure regulating valve (ARV) operation control> The control unit 3 controls the operation of the air pressure regulating valve ARV so that the pressure of the oxidizer gas supplied to the fuel cell FC remains constant during power generation or intermittent power generation by the fuel cell FC. This suppresses fluctuations in the flow rate of the oxidizer gas supplied from the air compressor ACP to the oxygen electrode of the fuel cell FC.

[0038] <Determining the fully charged state of energy storage device B> The control unit 3 determines that the energy storage device B is fully charged if its charge amount Ch is equal to or greater than the charge amount threshold, and determines that the energy storage device B is not fully charged if its charge amount Ch is less than the charge amount threshold. The charge amount threshold is set to a low level in advance so that even when the energy storage device B is fully charged, any surplus power not supplied from the fuel cell module 1 to the load Lo can be supplied to the energy storage device B.

[0039] <Operation control of DC-DC converter CNV when energy storage device B is not fully charged> If the control unit 3 determines that the energy storage device B is not fully charged, it drives the DC-DC converter CNV according to the charge amount Ch of the energy storage device B.

[0040] For example, the control unit 3 increases the target output voltage sent to the DC-DC converter CNV as the charge amount Ch of the energy storage device B increases, and decreases the target output voltage sent to the DC-DC converter CNV as the charge amount Ch of the energy storage device B decreases. The DC-DC converter CNV increases its output voltage as the target output voltage increases by increasing the duty cycle of the control signal that controls the on / off state of the switch SW. Conversely, the DC-DC converter CNV decreases its output voltage as the target output voltage decreases by decreasing the duty cycle of the control signal.

[0041] Furthermore, the control unit 3 performs high-potential avoidance processing to lower the voltage Vfc of the fuel cell FC (the voltage detected by the voltmeter SV1 or the average voltage of each fuel cell) by drawing current from the fuel cell FC to the energy storage device B when the voltage Vfc of the fuel cell FC is relatively high. Specifically, when the voltage Vfc of the fuel cell FC exceeds a voltage threshold, the control unit 3 controls the operation of the DC-DC converter CNV so that the current flowing from the fuel cell FC to the energy storage device B via the DC-DC converter CNV increases, thereby changing the voltage Vfc of the fuel cell FC to a voltage lower than the voltage threshold. This reduces the likelihood of the voltage Vfc of the fuel cell FC exceeding the voltage threshold, and thus suppresses the deterioration of the fuel cell FC due to a relatively high voltage Vfc.

[0042] <Control of the inverter INV when the energy storage device B is not fully charged> If the control unit 3 determines that the energy storage device B is not fully charged, it controls the operation of the inverter INV so that the power necessary to charge the energy storage device B is output from the fuel cell FC.

[0043] For example, if the control unit 3 determines that the energy storage device B is not fully charged, it controls the operation of the inverter INV so that the power output from the fuel cell FC changes in stages according to the charge amount Ch of the energy storage device B. That is, the control unit 3 controls the operation of the inverter INV so that power P3 is output from the fuel cell FC when the charge amount Ch of the energy storage device B is less than or equal to threshold th1. Also, the control unit 3 controls the operation of the inverter INV so that power P2 is output from the fuel cell FC when the charge amount Ch of the energy storage device B is greater than threshold th1 and less than or equal to threshold th2. Also, the control unit 3 controls the operation of the inverter INV so that power P1 is output from the fuel cell FC when the charge amount Ch of the energy storage device B is greater than threshold th2.

[0044] <Operation control of DC-DC converter CNV when energy storage device B is fully charged> When the control unit 3 determines that the energy storage device B is fully charged, it stops the DC-DC converter CNV because there is no need to charge the energy storage device B. In other words, when the control unit 3 determines that the energy storage device B is fully charged, it keeps the switch SW of the DC-DC converter CNV permanently off. When the DC-DC converter CNV is stopped (switch SW is open) and the voltage of the energy storage device B is greater than the voltage of the fuel cell FC, no current flows from the fuel cell FC to the energy storage device B via the diode D of the DC-DC converter CNV. On the other hand, when the DC-DC converter CNV is stopped and the voltage of the energy storage device B is less than the voltage of the fuel cell FC, current flows from the fuel cell FC to the energy storage device B via the diode D of the DC-DC converter CNV, and the voltage Vfc of the fuel cell FC gradually decreases.

[0045] Thus, when the energy storage device B is fully charged, the voltage Vfc of the fuel cell FC tends to fluctuate. Therefore, in the embodiment, the control unit 3 periodically generates power from the fuel cell FC and controls the operation of the inverter INV so that the voltage of the fuel cell FC remains constant, thereby suppressing deterioration of the fuel cell FC due to voltage fluctuations.

[0046] Furthermore, immediately after the vehicle Ve's idle stop, or immediately after the power necessary to drive load Lo is no longer supplied from fuel cell module 1 to load Lo, high potential avoidance is often performed, making it easier for energy storage device B to become fully charged.

[0047] <Control of the inverter INV when energy storage device B is fully charged> When the energy storage device B is fully charged, the control unit 3 controls the operation of the inverter INV so that the fuel cell FC generates power intermittently.

[0048] For example, during intermittent power generation by the fuel cell FC, the control unit 3 controls the operation of the inverter INV so that the voltage Vfc of the fuel cell FC fluctuates between an upper limit VH and a lower limit VL, causing the fuel cell FC to generate power periodically. The upper limit VH is any value less than the maximum output voltage (rated voltage) of the fuel cell FC or fuel cell cell. The lower limit VL is any value greater than the minimum output voltage of the fuel cell FC or fuel cell cell. For example, the upper limit VH and the lower limit VL may be determined by the voltage fluctuation range of the fuel cell FC when the fuel cell FC or fuel cell is not degraded.

[0049] In this way, during intermittent power generation of the fuel cell FC, by fluctuating the voltage Vfc of the fuel cell FC within a relatively narrow range between the upper limit VH and the lower limit VL, it is possible to suppress the deterioration of the fuel cell FC or each fuel cell due to fluctuations in the voltage Vfc of the fuel cell FC.

[0050] Figure 2 is a flowchart showing an example of the operation of the control unit 3.

[0051] First, if the control unit 3 determines that the energy storage device B is fully charged (step S101: Yes), it turns on the intermittent control flag to start intermittent power generation from the fuel cell FC (step S102) and obtains the voltage Vfc (step S103).

[0052] Next, the control unit 3 determines whether the voltage Vfc is less than or equal to the lower limit VL (step S104), or whether the voltage Vfc is greater than or equal to the upper limit VH (step S105). If the control unit 3 determines that the voltage Vfc is greater than the lower limit VL and less than the upper limit VH, it repeatedly executes steps S103 to S105.

[0053] Next, when the voltage Vfc falls below the lower limit VL (step S104: Yes), the control unit 3 calculates the stopping rotation angle θth (step S106), outputs the rotation command and the stopping rotation angle θth to the inverter INV (step S107), and waits until a certain period of time has elapsed since outputting the rotation command and the stopping rotation angle θth (step S108: No). For example, in step S106, the control unit 3 adds the rotation angle θ' corresponding to the total amount of oxidizer gas supplied to raise the voltage Vfc from the lower limit VL to the upper limit VH to the rotation angle θth detected by the sensor S. In step S106, the control unit 3 may also be configured to refer to information stored in the memory unit 2 beforehand, which shows the correspondence between the rotation angle of the motor M and the total amount of oxidizer gas supplied, and set the rotation angle θ' to the rotation angle corresponding to the total volume of oxidizer gas required to raise the voltage Vfc from the lower limit VL to the upper limit VH. With this configuration, when the air compressor ACP is replaced with a new one, the control unit 3 can continue to execute the flowchart shown in Figure 2 simply by updating the information corresponding to the new air compressor ACP.

[0054] On the other hand, when the voltage Vfc exceeds the upper limit VH (step S105: Yes), the control unit 3 outputs a stop command to the inverter INV (step S109). It is assumed that the upper limit VH and lower limit VL are set such that the time it takes from when the voltage Vfc falls below the lower limit VL until the rotation angle θ becomes greater than or equal to the stop rotation angle θth is shorter than the time it takes from when the voltage Vfc falls below the lower limit VL until the voltage Vfc exceeds the upper limit VH.

[0055] Next, if the control unit 3 determines that the energy storage device B remains fully charged after a certain period of time has elapsed since outputting the rotation command (step S108: Yes), or after outputting the stop command (step S109) (step S110: No), it repeats steps S103 to S109.

[0056] On the other hand, if the control unit 3 determines that the energy storage device B is not fully charged (step S110: Yes), it turns off the intermittent control flag (step S111) and terminates the intermittent power generation of the fuel cell FC.

[0057] Figure 3 is a flowchart showing an example of the operation of the inverter INV.

[0058] First, after the intermittent control flag is turned on (step S201: Yes), the inverter INV drives the motor M at the minimum rotational speed (step S203) when a rotation command and a stop rotation angle θth are input (step S202: Yes). The minimum rotational speed is defined as the rotational speed of the motor M when the smallest flow rate of oxidizer gas is output from the air compressor ACP. The inverter INV also stops the motor M from the time the intermittent control flag is turned on until a rotation command is input to the inverter INV. As a result, the supply of oxidizer gas from the air compressor ACP to the fuel cell FC is stopped from the time the intermittent control flag is turned on until a rotation command is input to the inverter INV, causing the voltage Vfc to gradually decrease. When a rotation command is input to the inverter INV, the motor M is driven at the minimum rotational speed, causing the voltage Vfc to gradually increase.

[0059] Next, when a stop command is input to the inverter INV (step S204: Yes), or when the rotation angle θ detected by the sensor S becomes greater than or equal to the stop rotation angle θth (steps S205, S206: Yes), the inverter INV stops the motor M (step S207). As a result, the supply of oxidizer gas from the air compressor ACP to the fuel cell FC stops, and the voltage Vfc gradually decreases.

[0060] Next, if the intermittent control flag remains on (step S208: No), the inverter INV repeats steps S202 to S207, and if the intermittent control flag is turned off (step S208: Yes), it terminates the operation control of the motor M.

[0061] Figure 4(a) shows an example of the change in voltage Vfc over time. In the two-dimensional coordinate system shown in Figure 4(a), the horizontal axis represents time, and the vertical axis represents voltage. The solid line in Figure 4(a) shows an example of the change in voltage Vfc over time.

[0062] Figure 4(b) shows an example of the change in the rotational speed of motor M over time. In the two-dimensional coordinate system shown in Figure 4(b), the horizontal axis represents time, and the vertical axis represents rotational speed. The solid line in Figure 4(b) shows an example of the change in the rotational speed of motor M over time. The time interval from t0 to t4 shown in Figure 4(b) is the same as the time interval from t0 to t4 shown in Figure 4(a).

[0063] Figure 4(c) is a schematic diagram showing an example of the correspondence between the rotation angle θ of the motor M and the total amount of oxidant gas supplied by the air compressor ACP. In the two-dimensional coordinate system shown in Figure 4(c), the horizontal axis represents the rotation angle, and the vertical axis represents the total amount of oxidant gas supplied. The solid line in Figure 4(c) shows an example of the correspondence between the rotation angle θ of the motor M and the total amount of oxidant gas supplied by the air compressor ACP. It is assumed that the total amount of oxidant gas supplied from the air compressor ACP to the fuel cell FC increases by A [ml] for every 90 [deg] increase in the rotation angle θ of the motor M. In other words, the air compressor ACP has the characteristic of increasing the amount of oxidant gas supplied in a stepwise manner for every constant increase in the rotation angle of the motor M.

[0064] In the configuration shown in Figures 4(a) to 4(c), for example, let's assume that the total amount of oxidizing gas supplied to raise the voltage Vfc from the lower limit VL to the upper limit VH is (A × 2) [ml].

[0065] First, at time t0, if the control unit 3 determines that the energy storage device B is fully charged, it turns on the intermittent control flag. As a result, the motor M stops temporarily, and the voltage Vfc gradually decreases.

[0066] Next, at time t1, when the voltage Vfc falls below the lower limit VL, the control unit 3 obtains 120 [deg] as the rotation angle θ detected by the sensor S, adds 270 [deg] corresponding to (A × 2) [ml] to 120 [deg] to obtain 390 [deg], which is the stop rotation angle θth, and outputs the rotation command and the stop rotation angle θth to the inverter INV. When the inverter INV receives the rotation command and the stop rotation angle θth, it drives the motor M and obtains 120 [deg] as the rotation angle θ detected by the sensor S.

[0067] Next, at time t2, when the rotation angle θ exceeds 390 degrees, the inverter INV stops the motor M. Then, the voltage Vfc gradually decreases.

[0068] Next, at time t3, when the voltage Vfc falls below the lower limit VL, the control unit 3 obtains 60 degrees as the rotation angle θ detected by the sensor S, adds 270 degrees (corresponding to (A × 2) ml) to 60 degrees, resulting in 330 degrees, which is the stop rotation angle θth. The control unit then outputs the rotation command and the stop rotation angle θth to the inverter INV. When the inverter INV receives the rotation command and the stop rotation angle θth, it drives the motor M and obtains 60 degrees as the rotation angle θ detected by the sensor S.

[0069] Then, at time t4, when the rotation angle θ exceeds 330 degrees, the inverter INV stops the motor M. As a result, the voltage Vfc gradually decreases.

[0070] Thus, according to the fuel cell module 1 of this embodiment, by setting the stop rotation angle θth to the sum of the rotation angle θ of the motor M corresponding to the total amount of oxidant gas supplied to increase the voltage Vfc of the fuel cell FC from the lower limit VL to the upper limit VH, and the current rotation angle θ, the motor M can be stopped when the voltage Vfc exceeds the upper limit VH. Therefore, even if the total amount of oxidant gas supplied from the air compressor ACP to the fuel cell FC increases nonlinearly with an increase in the rotation angle θ of the motor M, it is possible to suppress the voltage Vfc from exceeding the upper limit VH. As a result, fluctuations in the voltage Vfc of the fuel cell FC can be suppressed during intermittent power generation of the fuel cell FC, and the deterioration of the fuel cell FC can be suppressed.

[0071] Furthermore, according to the fuel cell module 1 of the embodiment, since the operation of the motor M is controlled using the voltage Vfc of the fuel cell FC, compared to a configuration in which the operation of the motor M is controlled using the driving time and stopping time of the motor M corresponding to the total amount of oxidant gas supplied to the fuel cell FC, it is possible to suppress the motor M stopping before it starts to drive due to the driving time of the motor M being too short, which would result in a relatively long stopping time for the motor M and prevent the voltage Vfc of the fuel cell FC from falling below the lower limit VL.

[0072] Furthermore, according to the fuel cell module 1 of the embodiment, even if the total amount of oxidant gas supplied from the air compressor ACP to the fuel cell FC increases non-linearly with increasing rotation angle θ of the motor M, the motor M can be stopped when the voltage Vfc of the fuel cell FC exceeds the upper limit VH, thereby preventing the voltage Vfc of the fuel cell FC from exceeding the upper limit VH.

[0073] Furthermore, according to the fuel cell module 1 of the embodiment, the configuration is such that the voltage Vfc of the fuel cell FC is varied using the voltage Vfc of the fuel cell FC and the rotation angle θ of the motor M. Therefore, even if one of the voltage Vfc and rotation angle θ cannot be obtained, the voltage Vfc of the fuel cell FC can be varied between an upper limit VH and a lower limit VL using the other.

[0074] Furthermore, according to the fuel cell module 1 of this embodiment, there is no need to prepare an expensive air compressor that can finely control the total amount of oxidizer gas supplied to the fuel cell FC in order to vary the voltage Vfc of the fuel cell FC from a lower limit VL to an upper limit VH, thus suppressing an increase in manufacturing costs.

[0075] Furthermore, according to the fuel cell module 1 of the embodiment, there is no need to avoid high potential for the fuel cell FC during intermittent power generation, which suppresses the voltage rise of the energy storage device B and improves the fuel efficiency of the fuel cell FC.

[0076] Furthermore, according to the fuel cell module 1 of the embodiment, when intermittent power generation of the fuel cell FC, it is possible to suppress the fuel cell FC voltage Vfc from exceeding the upper limit VH, thereby reducing the number of times the DC-DC converter CNV is driven and suppressing an unnecessary rise in the voltage of the energy storage device B.

[0077] It should be noted that the present invention is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of the invention. [Explanation of Symbols]

[0078] 1 Fuel cell module 2 Storage section 3. Control Unit Vehicle HT Hydrogen Tank INJ Injector ACP Air Compressor M Motor INV Inverter S sensor ARV Air Pressure Regulating Valve FC fuel cell CNV DC-DC converter L Inductor SW Switch D diode C Capacitor B Energy storage device SV1, SV2 Voltmeter SI ammeter Lo load

Claims

1. A fuel cell generates electricity through an electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidizing gas, An injector that adjusts the amount of fuel gas supplied to the fuel cell, An air compressor comprising a motor for adjusting the amount of oxidizer gas supplied to the fuel cell, a sensor for detecting the rotation angle of the motor, and an inverter for driving the motor, A control unit that controls the operation of the injector and the inverter, Equipped with, The control unit outputs a rotation command and a stop rotation angle to the inverter during intermittent power generation of the fuel cell. During intermittent power generation by the fuel cell, the inverter repeatedly drives the motor when the rotation command and the stop rotation angle are input, and stops the motor when the rotation angle detected by the sensor becomes greater than or equal to the stop rotation angle. Fuel cell module.

2. A fuel cell module according to claim 1, The air compressor increases the total amount of oxidizer gas supplied to the fuel cell each time the rotation angle of the motor increases by a certain rotation angle during intermittent power generation of the fuel cell. During intermittent power generation by the fuel cell, the control unit determines the stop rotation angle as the value obtained by adding the rotation angle corresponding to the total amount of oxidant gas supplied to raise the voltage of the fuel cell from the lower limit to the upper limit to the rotation angle detected by the sensor. Fuel cell module.

3. A fuel cell module according to claim 1, When the fuel cell is generating power intermittently, the control unit outputs a stop command to the inverter when the voltage of the fuel cell exceeds the upper limit, and outputs a rotation command to the inverter when the voltage of the fuel cell falls below the lower limit. The inverter stops the motor when the stop command is input during intermittent power generation by the fuel cell, or when the rotation angle detected by the sensor becomes greater than or equal to the stop rotation angle. Fuel cell module.

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