JP2022148029A - fuel cell system - Google Patents

Abstract

To provide a fuel cell system that inhibits a fuel cell from being deteriorated while inhibiting a power storage device from being in an overcharge state.SOLUTION: A fuel cell system 1 comprises: a fuel cell FC; a power storage device B connected between the fuel cell FC and a load Lo mounted on a vehicle Ve; accessories driven using power supplied from the fuel cell FC; and a control unit 2 for controlling power generation of the fuel cell FC and operation of the accessories. When regenerative power supplied from the vehicle Ve to the fuel cell system 1 is equal to or greater than predetermined power and acceleration of the vehicle Ve is equal to or smaller than predetermined acceleration, the control unit 2 stops power generation of the fuel cell FC and drives accessories not directly related to power generation of the fuel cell FC.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fuel cell system mounted on a vehicle.

As a fuel cell system installed in a vehicle, the electric power output from the fuel cell is supplied to a load such as a driving motor via a power storage device installed after the fuel cell, and the regenerated power output from the load is stored. There is something to feed the device.

However, the above fuel cell system has a problem that when the capacity of the power storage device is relatively small, the power storage device tends to be overcharged.

Therefore, if there is a risk that the power storage device will be overcharged due to the regenerated power, it is conceivable to consume the power supplied from the fuel cell by driving auxiliary equipment related to the power generation of the fuel cell. As a related technology, there is Patent Document 1.

JP 2015-144503 A

However, in the above fuel cell system, if the auxiliary equipment is forcibly driven in order to prevent the power storage device from being overcharged, the auxiliary equipment such as the auxiliary equipment for supplying the oxidant gas to the fuel cell, in particular, will cause the fuel cell to malfunction. If the auxiliary equipment directly related to power generation is forcibly driven, the output of the fuel cell will be at a high potential and the fuel cell may deteriorate.

SUMMARY OF THE INVENTION Accordingly, an object of one aspect of the present invention is to suppress deterioration of a fuel cell while suppressing an overcharged state of a power storage device in a fuel cell system.

A fuel cell system, which is one embodiment of the present invention, is a fuel cell system mounted on a vehicle, and includes a fuel cell and a power storage device connected between the fuel cell and a load mounted on the vehicle. an auxiliary device driven by electric power supplied from the fuel cell; and a control section for controlling power generation of the fuel cell and operation of the auxiliary device.

When the regenerated electric power supplied from the vehicle to the fuel cell system is equal to or greater than a predetermined electric power and the acceleration of the vehicle is equal to or less than a predetermined acceleration, the control unit stops power generation by the fuel cell. , drives the auxiliary equipment that is not directly involved in the power generation of the fuel cell.

Accordingly, when the regenerated electric power is equal to or higher than the predetermined electric power and the acceleration of the vehicle is equal to or lower than the predetermined acceleration, that is, there is a high possibility that the vehicle is traveling downhill and the power storage device is overcharged. If there is a risk of this happening, it is possible to stop the power generation of the fuel cell and drive auxiliary equipment that is not directly involved in the power generation of the fuel cell. Therefore, even if the electric power supplied from the fuel cell is consumed by the auxiliary equipment, it is possible to prevent the output of the fuel cell from becoming high potential, and to suppress deterioration of the fuel cell. That is, it is possible to suppress deterioration of the fuel cell while suppressing overcharge of the power storage device.

Further, when the regenerative electric power is equal to or greater than the predetermined electric power and the acceleration is equal to or less than the predetermined acceleration, the control unit stops power generation by the fuel cell, Among them, one or more of the auxiliary machines may be driven according to the amount of charge of the power storage device.

As a result, when there is a high possibility that the vehicle is traveling downhill and there is a risk that the power storage device will be in an overcharged state, the operation of one or more auxiliary devices can be appropriately controlled according to the amount of charge in the power storage device. Therefore, deterioration of the fuel cell can be suppressed while suppressing overcharge of the power storage device.

Further, the control unit increments a counter value when the regenerative power is equal to or greater than the predetermined power and when the acceleration is equal to or less than the predetermined acceleration, and when the regenerative power is smaller than the predetermined power, Alternatively, when the acceleration is greater than the predetermined acceleration, the counter value is decremented, and when the counter value becomes equal to or greater than a first threshold value, power generation by the fuel cell is stopped and the power generation by the fuel cell is not directly involved. You may comprise so that the said auxiliary machine may be driven.

As a result, it is possible to prevent the fuel cell from frequently stopping and restarting power generation due to fluctuations in the regenerated electric power and vehicle acceleration. In this way, it is possible to suppress the driver of the vehicle from feeling uncomfortable with the driving of the vehicle.

Further, the control unit may be configured to prepare to drive the auxiliary equipment that is not directly related to the power generation of the fuel cell when the counter value reaches or exceeds a second threshold that is smaller than the first threshold. .

As a result, compared to the case where preparations for driving the auxiliary machine are not made before the counter value becomes equal to or greater than the first threshold value, the auxiliary machine can be driven immediately after the counter value becomes equal to or greater than the first threshold value. Since the electric power supplied from the fuel cell can be consumed by the power storage device, it is possible to further prevent the power storage device from being overcharged.

Moreover, the power storage device may be configured by a capacitor.

In general, a capacitor has a relatively small capacity among secondary batteries and has excellent charging/discharging characteristics. Therefore, by configuring a power storage device with a capacitor, the charging/discharging characteristics of a fuel cell system can be relatively improved. can.

According to the present invention, in a fuel cell system, deterioration of the fuel cell can be suppressed while suppressing overcharge of the power storage device.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the fuel cell system of embodiment. FIG. 4 is a diagram showing an example of current and voltage output from a fuel cell; 7 is a flow chart showing an example of the operation of the control unit during downhill flag switching processing; 7 is a flowchart showing an example of the operation of the control unit during power generation control processing;

Embodiments will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an example of a fuel cell system according to an embodiment.

A fuel cell system 1 shown in FIG. 1 is mounted on an industrial vehicle such as a forklift or a vehicle Ve such as an automobile, and supplies electric power to a load Lo and the like. It should be noted that the load Lo is assumed to be an inverter or the like for driving a running motor mounted on the vehicle Ve.

The fuel cell system 1 also includes a fuel cell FC, a hydrogen tank HT, a hydrogen tank valve HTV, an injector INJ, a gas-liquid separator GLS, a hydrogen circulation pump HP, an exhaust/drain valve EDV, and an air compressor ACP. , an air pressure regulating valve ARV, an air shutoff valve ASV, a radiator R, a fan F, a water pump WP, an intercooler IC, a DCDC converter CNV, a power storage device B, and a control unit 2 . The hydrogen tank valve HTV, injector INJ, hydrogen circulation pump HP, exhaust/drain valve EDV, air compressor ACP, air pressure regulator ARV, air shut valve ASV, fan F, and water pump WP are connected to the fuel cell FC (DCDC converter CNV ) that consumes the power supplied from the In particular, as the number of revolutions of the motors for driving the hydrogen circulating pump HP, air compressor ACP, fan F, and water pump WP increases, the amount of power supplied from the fuel cell FC increases. Auxiliary equipment such as the air compressor ACP and the injector INJ are assumed to be auxiliary equipment directly related to the power generation of the fuel cell FC. Auxiliaries such as the hydrogen circulation pump HP, the fan F, and the water pump WP are assumed to be auxiliary equipment that are not directly related to the power generation of the fuel cell FC. That is, the auxiliary equipment directly related to the power generation of the fuel cell FC can be rephrased as an auxiliary equipment that additionally supplies reaction gas (fuel gas and oxidant gas, which will be described later) to the fuel cell FC. The irrelevant auxiliaries can be rephrased as auxiliaries that do not additionally supply the reaction gas to the fuel cell FC.

A fuel cell FC is a fuel cell stack composed of a plurality of fuel cells connected in series with each other. Electricity is generated by an electrochemical reaction.

The hydrogen tank HT is a fuel gas storage container. The fuel gas stored in the hydrogen tank HT is supplied to the fuel cell FC through the hydrogen tank valve HTV and the injector INJ.

The hydrogen tank valve HTV reduces the pressure of the fuel gas supplied to the fuel cell FC.

The injector INJ adjusts the flow rate of fuel gas supplied to the fuel cell FC.

The gas-liquid separator GLS separates fuel gas and liquid water discharged from the fuel cell FC.

The hydrogen circulation pump HP resupplies the fuel gas separated by the gas-liquid separator GLS to the fuel cell FC.

The exhaust drain valve EDV discharges the liquid water separated by the gas-liquid separator GLS to the outside.

The air compressor ACP compresses the oxidant gas and supplies it to the fuel cell FC via the intercooler IC and the air shut valve ASV.

The intercooler IC heat-exchanges the oxidant gas with a refrigerant such as cooling water flowing through the intercooler IC.

The air shut valve ASV cuts off the oxidant gas supplied to the fuel cell FC.

The air pressure regulating valve ARV regulates the pressure and flow rate of the oxidant gas supplied to the fuel cell FC.

The radiator R exchanges the heat of the coolant heated by the heat generated by the fuel cell with the outside air.

The fan F increases the heat dissipation amount of the radiator R. It is assumed that the fuel cell system 1 has a bypass flow path P that connects the input and output of the radiator R. As a result, the coolant output from the fuel cell FC can be supplied to the water pump WP without going through the radiator R. Therefore, the number of revolutions of the motor for driving the fan F is increased to increase the heat radiation amount of the radiator R. It is possible to suppress the refrigerant from entering a supercooled (overcooled) state even if the temperature is raised.

The water pump WP supplies coolant cooled by the radiator R to the fuel cell FC via the intercooler IC.

The DCDC converter CNV is provided after the fuel cell FC and supplies the power storage device B with electric power output from the fuel cell FC. It is assumed that power storage device B is supplied with power remaining after the power is consumed by the auxiliary equipment, out of the power output from DCDC converter CNV.

The power storage device B is provided between the DCDC converter CNV and the load Lo, and supplies power to the load Lo and accessories such as the hydrogen circulation pump HP, the air compressor ACP, the fan F, and the water pump WP. Note that the power storage device B may be configured by a capacitor such as a lithium ion capacitor. In general, a capacitor has a relatively small capacity among secondary batteries and has excellent charging/discharging characteristics. Therefore, by configuring the power storage device B with a capacitor, the charging/discharging characteristics of the fuel cell system 1 can be relatively improved. be able to.

The control unit 2 is composed of a microcomputer or the like including a CPU that performs logic operations from a program stored in memory.

During normal power generation control, the control unit 2 controls the hydrogen tank valve HTV, the injector INJ, the hydrogen circulation pump HP, the exhaust/drain valve EDV, and the air compressor ACP so that the power generated in the fuel cell FC reaches the target power Pt. , air pressure regulating valve ARV, air shutoff valve ASV, fan F, and water pump WP. For example, when the fuel cell FC starts generating power, the control unit 2 turns on the power of the motors for driving various auxiliary devices, and then outputs a command value indicating the target rotation speed of each motor.

Further, the control unit 2 changes the target power Pt according to the amount of charge in the power storage device B during normal power generation control. Note that the amount of charge is the ratio [%] (charging rate) of the current capacity to the fully charged capacity of power storage device B, or the voltage [V] of power storage device B when no current is flowing through power storage device B. do.

Further, control unit 2 may be configured to change target electric power Pt in a stepwise manner according to the amount of charge in power storage device B. FIG. For example, it is assumed that charging rate SOC1<charging rate SOC2<charging rate SOC3<charging rate SOC4<charging rate SOC5<charging rate SOC6 and target power Pt1<target power Pt2. In this case, when the charging rate of power storage device B decreases within the range of charging rate SOC3 to charging rate SOC5, control unit 2 sets target power Pt1 as target power Pt, and the charging rate of power storage device B is If the target power Pt is set to the target generated power Pt2 in the range of the rate SOC1 to the charging rate SOC3, and if the charging rate of the power storage device B is increasing in the range of the charging rate SOC2 to the charging rate SOC4, Target power Pt2 is set as target power Pt, and when the charging rate of power storage device B increases within the range of charging rate SOC4 to charging rate SOC6, target power Pt1 is set as target power Pt.

Here, FIG. 2 is a diagram showing an example of current and voltage output from the fuel cell FC. The horizontal axis of the two-dimensional coordinates shown in FIG. 2 indicates the current [A], the vertical axis indicates the voltage [V], and the solid line indicates the correspondence relationship between the current and the voltage output from the fuel cell FC.

As shown in FIG. 2, the voltage output from the fuel cell FC increases as the current output from the fuel cell FC decreases. Further, when the voltage output from the fuel cell FC becomes relatively high, the catalyst necessary for the electrochemical reaction is ionized, and the next time the voltage output from the fuel cell FC becomes relatively low, the crystals of the ionized catalyst increases, the particle size of the catalyst increases and the surface area of the catalyst decreases, which may deteriorate the fuel cell FC.

Therefore, in the control unit 2 of the embodiment, when the output voltage of the fuel cell FC becomes equal to or higher than the predetermined voltage Vc, the DCDC converter CNV is forcibly driven to increase the current flowing from the fuel cell FC to the DCDC converter CNV. , lowers the voltage output from the fuel cell FC. This prevents the voltage output from the fuel cell FC from becoming relatively large during idling when the vehicle Ve is temporarily stopped while waiting for a signal and the current flowing from the fuel cell system 1 to the load Lo becomes relatively small. Therefore, deterioration of the fuel cell FC can be suppressed.

It is also assumed that when the vehicle Ve is traveling downhill, the regenerated electric power supplied from the vehicle Ve (load Lo) to the fuel cell system 1 becomes relatively large. Also, when the vehicle Ve is running downhill, the acceleration of the vehicle Ve is relatively decreased by the driver operating the accelerator of the vehicle Ve so that the speed of the vehicle Ve becomes constant. .

Therefore, when the regenerated electric power supplied from the vehicle Ve to the fuel cell system 1 is relatively large and the acceleration of the vehicle Ve is relatively small, there is a high possibility that the vehicle Ve is running downhill.

When the vehicle Ve is traveling downhill, there is a high possibility that the power storage device B will be overcharged due to the regenerative electric power being supplied from the vehicle Ve to the fuel cell system 1 for a relatively long period of time. There is a concern that

Therefore, in the control unit 2 of the embodiment, when the regenerated electric power supplied from the vehicle Ve to the fuel cell system 1 is equal to or greater than a predetermined electric power and the acceleration of the vehicle Ve is equal to or less than a predetermined acceleration, the vehicle Ve is likely to be running downhill and there is a risk that the power storage device B will be in an overcharged state. , to forcibly drive auxiliary devices that are not directly related to the power generation of the fuel cell FC.

Note that the control unit 2 multiplies the voltage output from the vehicle Ve to the fuel cell system 1 by the current flowing from the vehicle Ve to the fuel cell system 1, and converts the regenerated power supplied from the vehicle Ve to the fuel cell system 1 to and In addition, the control unit 2 receives the speed [km/h] of the vehicle Ve from a travel control unit (not shown) mounted on the vehicle Ve, and calculates the amount of change in the speed of the vehicle Ve per unit time as the acceleration of the vehicle Ve. and The speed of the vehicle Ve is (rotational speed of travel motor x outer diameter of tire x circumference ratio)/(gear ratio x reduction ratio). Alternatively, the control unit 2 receives the acceleration of the vehicle Ve determined by the acceleration sensor from the travel control unit.

As described above, in the control unit 2 of the embodiment, when there is a high possibility that the vehicle Ve is running downhill and there is a risk that the power storage device B will be overcharged, the power generation of the fuel cell FC is stopped. , drives auxiliary devices that are not directly related to the power generation of the fuel cell FC. As a result, even if the power supplied from the fuel cell FC is consumed by the auxiliary equipment so that the power storage device B does not become overcharged, it is possible to suppress the output of the fuel cell FC from becoming a high potential. Deterioration of the battery FC can be suppressed. That is, it is possible to suppress the deterioration of the fuel cell FC while suppressing the power storage device B from being overcharged.

When the regenerated power supplied from the vehicle Ve to the fuel cell system 1 is relatively small, the power storage device B is unlikely to be overcharged, and it is necessary to stop the power generation of the fuel cell FC or drive the auxiliary equipment. Therefore, the control unit 2 continues normal power generation control.

Further, when the regenerated electric power supplied from the vehicle Ve to the fuel cell system 1 is relatively large, but the acceleration of the vehicle Ve is relatively large, when the vehicle Ve decelerates while traveling on a flat road, a temporary Since there is a high possibility that the regenerated electric power has become relatively large at this time and there is no need to stop the power generation of the fuel cell FC or drive the auxiliary equipment, the control unit 2 continues the normal power generation control.

Further, the control unit 2 increments the counter value when the regenerated electric power is equal to or greater than the predetermined electric power and the acceleration of the vehicle Ve is equal to or less than the predetermined acceleration, and when the regenerated electric power is smaller than the predetermined electric power or the vehicle When the acceleration of Ve is greater than a predetermined acceleration, the counter value is decremented, and when the counter value reaches or exceeds a threshold value C1th (first threshold value), it is determined that the vehicle Ve is running downhill and the downhill flag is turned on. do. Further, when the downhill flag is turned on, the control unit 2 stops the power generation of the fuel cell FC and drives the auxiliary equipment that is not directly related to the power generation of the fuel cell FC. That is, the control unit 2 increments the counter value when the regenerated electric power is equal to or higher than the predetermined electric power and the acceleration of the vehicle Ve is equal to or lower than the predetermined acceleration, and when the regenerated electric power is smaller than the predetermined electric power or the vehicle When the acceleration of Ve is greater than a predetermined acceleration, the counter value is decremented, and when the counter value reaches or exceeds the threshold value C1th, power generation of the fuel cell FC is stopped while auxiliary devices not directly related to power generation of the fuel cell FC are driven.

As a result, it is possible to prevent the fuel cell FC from frequently stopping and restarting power generation due to fluctuations in the regenerative electric power and the acceleration of the vehicle Ve. The repetition can reduce the influence on the driving of the vehicle Ve, and can prevent the driver of the vehicle Ve from feeling uncomfortable with the driving of the vehicle Ve.

Further, the control unit 2 may be configured to prepare to drive auxiliary equipment not directly related to the power generation of the fuel cell FC when the counter value reaches or exceeds a threshold value C2th (second threshold value) which is smaller than the threshold value C1th. .

As a result, compared to the case where preparations for driving the auxiliary equipment are not made before the counter value reaches the threshold value C1th or more, the auxiliary equipment is driven immediately after the counter value reaches the threshold value C1th or more and the fuel cell FC Since the power supplied from the power storage device B can be consumed, it is possible to further prevent the power storage device B from being overcharged.

Further, when the regenerated electric power is equal to or greater than the predetermined electric power and the acceleration of the vehicle Ve is equal to or less than the predetermined acceleration, the control unit 2 stops power generation of the fuel cell FC, and then, among the plurality of auxiliary machines, It may be configured to drive one or more auxiliary machines according to the amount of charge in power storage device B. FIG.

Here, it is assumed that the control unit 2 performs any one of the following operation controls 1) to 4) as the operation control of the auxiliary equipment when the power generation of the fuel cell FC is stopped.

1) The number of rotations of the motor for driving the water pump WP is set to the maximum number of rotations.

2) The number of rotations of the motors for driving the water pump WP and the hydrogen circulation pump HP is set to the maximum number of rotations.

3) The number of rotations of the motors for driving the water pump WP, the hydrogen circulation pump HP, and the fan F is set to the maximum number of rotations.

4) The number of rotations of the motors for driving the water pump WP, the hydrogen circulation pump HP, and the fan F is set to the maximum number of rotations, and the number of rotations of the motor for driving the air compressor ACP and the number of rotations of the motor for driving the air compressor ACP are reduced to avoid high potential. A predetermined voltage Vc is increased.

When the operation control of 4) above is performed, the amount of power supplied from the fuel cell FC is the largest, and when the operation control of above 3) is performed, the amount of power supplied from the fuel cell FC is consumed. is the second largest, and when the operation control of 2) above is performed, the consumption of the power supplied from the fuel cell FC is the third largest, and when the operation control of above 1) is performed, the power supplied from the fuel cell FC shall consume the least amount of power. Further, when the operation control of 1) above is performed, the degree of influence on the deterioration of the fuel cell FC is the lowest, and when the operation control of the above 2) is performed, the degree of influence on the deterioration of the fuel cell FC is the second lowest, When the operation control of 3) above is performed, the degree of influence on deterioration of the fuel cell FC is the third lowest, and when the operation control of above 4) is performed, the degree of influence on deterioration of the fuel cell FC is the fourth lowest. shall be Further, threshold S1th<threshold S2th<threshold S3th<threshold S4th.

In this case, when the regenerated electric power is equal to or higher than the predetermined electric power and the acceleration of the vehicle Ve is equal to or lower than the predetermined acceleration, the control unit 2 stops the power generation of the fuel cell FC, and then the charge amount of the electric storage device B is equal to or greater than the threshold S1th, the operation control of the above 1) is performed, and if the charge amount of the power storage device B is equal to or more than the threshold S2th, the operation control of the above 2) is performed, and the charge amount of the power storage device B is equal to or greater than the threshold S3th. , the operation control of the above 3) is performed, and when the charge amount of the power storage device B is equal to or greater than the threshold value S4th, the operation control of the above 4) is performed.

As a result, when the amount of charge in the power storage device B is equal to or greater than the threshold value S1th when the power generation of the fuel cell FC is stopped, the operation control of the above 1) is performed by the control unit 2. It is possible to consume the electric power of the power storage device B while making it the lowest. Further, when the charge amount of the power storage device B is equal to or greater than the threshold value S2th when the power generation of the fuel cell FC is stopped, the operation control of the above 2) is performed by the control unit 2, so the degree of influence on the deterioration of the fuel cell FC is compared. The power of the power storage device B can be consumed while the target is lowered. Further, when the power generation of the fuel cell FC is stopped, if the charge amount of the power storage device B is equal to or greater than the threshold value S3th, the operation control of the above 3) is performed by the control unit 2, so that the power consumption of the power storage device B is compared. It is possible to suppress the degree of influence on deterioration of the fuel cell FC while increasing the target. Further, when the amount of charge in the power storage device B is equal to or greater than the threshold value S4th when the power generation of the fuel cell FC is stopped, the operation control of the above 4) is performed by the control unit 2, so that the power consumption of the power storage device B is minimized. It is possible to suppress the degree of influence on deterioration of the fuel cell FC while enlarging it.

In this manner, when there is a high possibility that the vehicle Ve is traveling downhill and there is a risk that the power storage device B will be overcharged, the operation control of the auxiliary equipment is appropriately performed according to the amount of charge in the power storage device B. Therefore, deterioration of the fuel cell FC can be suppressed while preventing the power storage device B from being overcharged.

FIG. 3 is a flowchart showing an example of the operation of the control unit 2 during downhill flag switching processing.

First, when the regenerative electric power supplied from the vehicle Ve to the fuel cell system 1 is equal to or greater than a predetermined electric power and the acceleration of the vehicle Ve is equal to or less than a predetermined acceleration (step S11: Yes), the control unit 2 controls the counter is incremented (step S12).

Next, when the counter value is equal to or greater than the threshold value C2th (second threshold value) (step S13: Yes), the control unit 2 prepares to drive various accessories (step S14).

Next, when the counter value is equal to or greater than the threshold value C1th (first threshold value) (step S15: Yes), the control unit 2 sets the counter value to the same value as the threshold value C1th, and turns on the downhill flag (step S16). , the descending slope flag switching process is terminated.

On the other hand, when the regenerated electric power supplied from the vehicle Ve to the fuel cell system 1 is smaller than the predetermined electric power, or when the acceleration of the vehicle Ve is greater than the predetermined acceleration (step S11: No), the control unit 2 changes the counter value of the counter. is decremented (step S17).

Next, when the counter value is equal to or less than zero (step S18: Yes), the control unit 2 sets the counter value to zero and turns off the descending slope flag (step S19), and ends the descending slope flag switching process.

In addition, the control unit 2 determines if the counter value is smaller than the threshold value C2th (step S13: No), or if the counter value is smaller than the threshold value C1th (step S15: No), or if the counter value is larger than zero (step S18: No), the descending slope flag switching process is terminated.

FIG. 4 is a flowchart showing an example of the operation of the control unit 2 during power generation control processing.

First, when the downhill flag is off (step S21: No), the control unit 2 performs normal power generation control (step S22).

On the other hand, when the downhill flag is ON (step S21: Yes), the control unit 2 stops the power generation of the fuel cell FC (step S23).

Next, when the amount of charge in the power storage device B reaches or exceeds the threshold value S1th (step S24: Yes), the control unit 2 sets the command value so that the rotation speed of the motor for driving the water pump WP reaches the maximum rotation speed. Output (step S25).

Next, when the amount of charge in the power storage device B reaches or exceeds the threshold value S2th (step S26: Yes), the control unit 2 sets the command value so that the number of revolutions of the motor for driving the hydrogen circulation pump HP reaches the maximum number of revolutions. is output (step S27). It is assumed that in step S27, the control unit 2 continues to output a command value for increasing the rotation speed of the motor for driving the water pump WP to the maximum rotation speed.

Next, when the amount of charge in the power storage device B reaches or exceeds the threshold value S3th (step S28: Yes), the control unit 2 sets the command value so that the rotation speed of the motor for driving the fan F reaches the maximum rotation speed. (Step S29). It is assumed that the control unit 2 continues to output the command value for causing the motors for driving the water pump WP and the hydrogen circulating pump HP to reach the maximum number of revolutions in step S29.

Then, when the amount of charge in the power storage device B reaches or exceeds the threshold value S4th (step S30: Yes), the control unit 2 increases the rotation speed of the motor for driving the air compressor ACP and the predetermined voltage Vc for high potential avoidance ( step S31). It should be noted that in step S31, the control unit 2 continues to output command values for causing the motors for driving the water pump WP, the hydrogen circulating pump HP, and the fan F to reach their maximum rotational speeds. do.

The present invention is not limited to the above embodiments, and various improvements and modifications are possible without departing from the gist of the present invention.

1 Fuel cell system 2 Control unit Ve Vehicle Lo Load FC Fuel cell HT Hydrogen tank HTV Hydrogen tank valve INJ Injector GLS Gas-liquid separator HP Hydrogen circulation pump EDV Exhaust drain valve ACP Air compressor ARV Air pressure regulating valve ASV Air shut valve R Radiator F Fan WP Water pump IC Intercooler CNV DCDC converter B Power storage device

Claims (5)

A fuel cell system mounted on a vehicle,
a fuel cell;
a power storage device connected between the fuel cell and a load mounted on the vehicle;
a plurality of auxiliary machines driven by electric power supplied from the fuel cell;
a control unit that controls the power generation of the fuel cell and the operation of the auxiliary equipment;
with
When the regenerated electric power supplied from the vehicle to the fuel cell system is equal to or greater than a predetermined electric power and the acceleration of the vehicle is equal to or less than a predetermined acceleration, the control unit stops power generation by the fuel cell. , a fuel cell system that drives the auxiliary equipment that is not directly involved in the power generation of the fuel cell. The fuel cell system according to claim 1,
When the regenerated electric power is equal to or greater than the predetermined electric power and the acceleration is equal to or less than the predetermined acceleration, after stopping power generation of the fuel cell, among the plurality of auxiliary machines, A fuel cell system that drives one or more of the auxiliary devices according to the amount of charge in the power storage device. 3. The fuel cell system according to claim 1 or 2,
The control unit
incrementing a counter value when the regenerative power is equal to or greater than the predetermined power and the acceleration is equal to or less than the predetermined acceleration;
decrementing the counter value when the regenerative power is less than the predetermined power or when the acceleration is greater than the predetermined acceleration;
A fuel cell system, wherein when the counter value reaches or exceeds a first threshold value, power generation of the fuel cell is stopped, and the auxiliary device not directly related to power generation of the fuel cell is driven. The fuel cell system according to claim 3,
The fuel cell system, wherein the control unit makes preparations for driving the auxiliary equipment that is not directly related to power generation of the fuel cell when the counter value reaches or exceeds a second threshold that is smaller than the first threshold. The fuel cell system according to any one of claims 1 to 4,
The fuel cell system, wherein the power storage device is a capacitor.

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