JP5602079B2 - Fuel cell system and method - Google Patents

Description

  The present invention relates to a fuel cell system that copes with high temperature and high load of a fuel cell and a control method thereof.

  In a fuel cell vehicle, humidification is performed on the reaction gas supplied to the fuel cell in order to keep the electrodes of the fuel cell in a predetermined wet state. However, if the high temperature and high load state of the fuel cell continues during high speed traveling or climbing, the fuel cell output power is reduced due to insufficient humidification of the reaction gas or increased volatilization of moisture from the fuel cell electrodes. As a result, the output of the motor is greatly reduced from the required amount.

  Patent Document 1 discloses a fuel cell system that prevents deterioration of the fuel cell. According to the fuel cell system, the maximum temperature in the fuel cell is estimated from the output current of the fuel cell, and the estimated maximum temperature in the fuel cell is equal to or lower than the upper limit temperature limit of the membrane electrode structure of the fuel cell. Controls the flow rate of refrigerant for cooling the fuel cell.

  Patent Document 2 discloses a fuel cell system that prevents a temperature drop of a fuel pressure reducing valve. According to the fuel cell system, the cooling water for cooling the compressor that supplies the oxidant gas to the fuel cell is supplied to the fuel pressure reducing valve instead of the radiator as the heat radiating portion of the cooling water when the fuel pressure reducing valve needs to be warmed up. The fuel pressure reducing valve is heated by the cooling water heated by the compressor.

JP 2008-191742 A JP 2004-158371 A

  In the fuel cell system of Patent Document 1, the fuel cell is cooled by the refrigerant so that the fuel cell temperature falls within an appropriate range, and the fuel becomes maximum when the fuel cell temperature reaches the upper limit set temperature. The cooling control of the fuel cell is performed. Therefore, when the fuel cell continues to be in a high load state and the fuel cell temperature exceeds the upper limit set temperature due to insufficient cooling capacity, the fuel cell temperature cannot be returned to the upper limit set temperature or lower, and the output power of the fuel cell Decreases. Therefore, when applied to a system in which a motor is driven by the output power of a fuel cell, such as a fuel cell vehicle, the output of the motor decreases when the fuel cell becomes hot.

  Therefore, in the fuel cell system of Patent Document 1, the cooling capacity of the cooling means of the fuel cell is sufficiently increased so that the fuel cell temperature is equal to or lower than the upper limit set temperature even if the high load state of the fuel cell continues. In this case, even if there is a margin for increasing the total output power of the fuel cell and battery, the cooling means will operate at maximum cooling power as long as the fuel cell temperature is close to the upper limit temperature. This leads to a significant increase in the time during which the cooling means operates at the maximum cooling power, and causes an increase in power consumption.

  The fuel cell system of Patent Document 2 does not mention any cooling control of the fuel cell when the fuel cell exceeds the upper limit set temperature with respect to heating of the fuel pressure reducing valve during warm-up.

  An object of the present invention is to provide a fuel cell system and a control method therefor that improve the motor output when the fuel cell is kept in a high temperature and high load state while suppressing the power used for cooling the fuel cell.

  A fuel cell system according to a first aspect of the present invention includes a motor, a fuel cell that charges the storage battery and supplies power to the motor and other electrical components in cooperation with the storage battery, and a cooling unit that cools the fuel cell; The temperature detection means for detecting the temperature of the fuel cell, the load state detection means for detecting the load state of the fuel cell, the current upper limit output power of the fuel cell and the current upper limit output power of the storage battery are summed Upper limit output power calculating means for calculating the current total upper limit output power, motor required power calculating means for calculating the required motor power required for the motor to output the requested output, the total upper limit output power, and the Based on the required motor power and the current supply power to the other electrical components, it is determined whether or not the motor output is in a non-margin state, and the fuel cell temperature and fuel It is determined whether or not the fuel cell is in a high temperature and high load continuation state based on the pond load, the fuel cell temperature, and the duration of the predetermined state for the fuel cell load. And if a fuel cell is a high temperature high load continuation state, it has the cooling promotion means which increases the cooling capacity of the said cooling means and falls the said fuel cell temperature to below 1st predetermined value, It is characterized by the above-mentioned.

  According to the first aspect of the present invention, when the fuel cell is in a state where the motor output is not in a surplus state, the cooling capacity of the fuel cell is increased during the high temperature and high load continuation state of the fuel cell, thereby improving the wet state of the fuel cell electrode. The output of the fuel cell can be increased and the motor output can be improved. In addition, although the cooling operation is performed at the maximum cooling capacity by the cooling means in the continuous high temperature and high load state of the fuel cell, the cooling operation is lower than the maximum cooling capacity in the normal high temperature state of the fuel cell. It is possible to save power consumption during the entire operation period.

  In the fuel cell system of the second invention, in the fuel cell system of the first invention, the cooling promoting means is configured such that the sum of the motor required power and the current supply power to the other electrical components is the total upper limit output power. When it exceeds, it is judged that the motor output is in a non-margin state.

  According to the second invention, when the sum of the motor required power and the current supply power to the other electrical components exceeds the total upper limit output power, it is determined that the motor output is in a non-margin state, In addition to saving power consumption and improving motor output, the drivability of the motor can be improved by accurately grasping when the output of the fuel cell increases due to cooling of the fuel cell.

  In the fuel cell system according to a third aspect of the present invention, in the first or second aspect of the invention, the cooling promoting means has a fuel cell temperature not less than a second predetermined value not less than the first predetermined value and a fuel cell load not less than a predetermined value. When a certain state continues for a predetermined time or more, it is determined that the fuel cell is in a high temperature and high load continuing state.

  According to the third invention, when the state where the fuel cell temperature is equal to or higher than the first predetermined value and the fuel cell load is equal to or higher than the predetermined value continues for a predetermined time or more, it is determined that the fuel cell is in the high temperature and high load continuing state. Accordingly, it is possible to accurately grasp when the output of the fuel cell is increased due to cooling of the fuel cell, and to improve the drivability of the motor in addition to saving the power consumption and improving the motor output.

  In a fuel cell system according to a fourth aspect of the present invention, in the fuel cell system according to any one of the first to third aspects, the refrigerant radiator for cooling the fuel cell is adjacent to a refrigerant condenser for an air conditioner, and the condenser is The cooling promotion means is arranged to be cooled by the cooling air after passing, and the cooling capacity of the cooling means is increased by decreasing the temperature adjustment amount by the air conditioner. .

  According to the fourth aspect of the invention, the promotion of the cooling of the fuel cell suppresses the rise in temperature when the cooling air passes through the condenser due to the decrease in the temperature adjustment amount by the air conditioner. Achieved in cooling. That is, it is possible to promote the cooling of the fuel cell irrespective of the performance increase of the cooling fan and the cooling pump, and it is possible to suppress the increase in cost in addition to the above-mentioned power consumption saving and the improvement of the motor output.

A fuel cell system according to a fifth aspect of the present invention is a fuel cell system mounted on a vehicle, the motor driving a drive wheel of the vehicle, the electrical components mounted on the vehicle excluding the motor, the motor and the electrical component. A storage battery for supplying power to the product, a fuel cell for supplying power to the motor and the electrical component, charging the storage battery, temperature detecting means for detecting the temperature of the fuel cell, and cooling the fuel cell A cooling pump for circulating the refrigerant in the circulation path; a radiator for the fuel cell disposed in the circulation path; a radiator fan for generating cooling air for cooling the radiator for the fuel cell; device, a power which can be output at the present time from the fuel cell and the storage battery, and the required motor power required to produce an output that the motor is required, the electrical component Based on the power consumption of the time, the motor output is determined whether the non-margin conditions, the fuel cell is a predetermined high temperature and high load state based on the output of the temperature and the fuel cell of the fuel cell If it is determined that the motor output is in a marginal state and the predetermined high temperature and high load state continues for a predetermined time or more, the rotation speed of the cooling pump is increased. Or the rotational speed of the radiator fan is increased.
The fuel cell system according to a sixth aspect of the present invention is the fuel cell system according to the fifth aspect, wherein the fuel cell radiator is cooled by cooling air after passing through the refrigerant capacitor adjacent to a refrigerant capacitor of an air conditioner included in the electrical component. If the control device determines that the motor output is in a marginal state and the predetermined high temperature and high load state continues for a predetermined time or longer, the fuel cell is The temperature adjustment amount of the air conditioner is decreased until the high temperature and high load state is removed.
According to a seventh aspect of the present invention, there is provided a control method comprising: a motor; a fuel cell that charges the storage battery and supplies power to the motor and other electrical components in cooperation with the storage battery; and a cooling unit that cools the fuel cell. A fuel cell system control method comprising: a temperature detection step for detecting a temperature of the fuel cell; a load state detection step for detecting a load state of the fuel cell; a current upper limit output power of the fuel cell; An upper limit output power calculation step for calculating a current total upper limit output power obtained by adding up the current upper limit output power of the storage battery, and a motor required power for calculating a motor required power required for the motor to output the requested output Based on the calculation step, the total upper limit output power, the motor required power, and the current supply power to the other electrical components, the motor output is in a marginal state. And whether or not the fuel cell is in the high temperature and high load continuation state based on the fuel cell temperature, the fuel cell load, the fuel cell temperature, and the duration of the predetermined state for the fuel cell load. If the result of the determination is that the motor output is in a marginal state and the fuel cell is in a high temperature and high load continuation state, the cooling capacity of the cooling means is increased and the fuel cell temperature is reduced to a first predetermined value or less. And a cooling promotion step of lowering.

According to the seventh aspect of the present invention, when the fuel cell is in a non-margin state and the fuel cell is in a high temperature and high load continuation state, the cooling capacity of the fuel cell is increased to improve the wet state of the fuel cell electrode. The output of the fuel cell can be increased and the motor output can be improved. Also, the power consumption can be saved because the maximum cooling capacity of the fuel cell is not used except when the fuel cell is kept in a high temperature and high load state.

The block diagram of a fuel cell system. The figure explaining the change of the output voltage of the fuel cell stack resulting from the running state of the fuel cell vehicle in relation to the relationship between the coolant temperature and the output voltage of the fuel cell stack. The flowchart of the cooling control of the fuel cell stack in a fuel cell system. The flowchart of the routine which determines the output margin of a motor. The flowchart of the routine which determines the high temperature high load continuation state of a fuel cell stack. Explanatory drawing of the high temperature and high load state of the fuel cell stack defined from the water temperature and output of the fuel cell stack. The flowchart of the cooling promotion routine of a fuel cell stack.

  In FIG. 1, a fuel cell system 10 is mounted on a fuel cell vehicle and includes a fuel cell stack 11, a high voltage battery 12, an electronic drive device 13, a cooling water circulation path 14, and a cooling control device 15. The fuel cell vehicle travels by operating the motor 37 of the electronic drive device 13 with the electric power generated in the fuel cell stack 11 and driving the drive wheels (not shown) by the motor 37.

  The fuel cell stack 11 generates electricity using hydrogen and oxygen in the air as reaction gases. The fuel cell stack 11 is connected to the vehicle control unit 27 of the electronic drive device 13 via the power cable 33, and the high voltage battery 12 is connected to the vehicle control unit 27 via the power cable 34.

  The high voltage battery 12 as a rechargeable battery is charged by supplying a part of the electric power generated by the fuel cell stack 11 via the vehicle control unit 27. The fuel cell stack 11 and the high voltage battery 12 jointly supply power to electrical components mounted on the fuel cell vehicle. The electrical components include a cooling control device 15, an FC (FC: Fuel Cell) radiator fan 22, a motor for driving the FC cooling water pump 23 (not shown), a vehicle control unit 27, a motor 37, and the like. In addition to the machine, electric devices such as air conditioners and car navigation systems are also included.

  The cooling water circulation path 14 constitutes a circulation path that circulates around the fuel cell stack 11, the FC radiator 21 and the FC cooling water pump 23, and guides the cooling water. The air conditioner capacitor 20, the FC radiator 21 and the FC radiator fan 22 are disposed in the hood chamber in the order described from the front in the front-rear direction of the fuel cell vehicle. The air conditioner capacitor 20 and the FC radiator fan 22 are adjacent to each other. The cooling air W flows into the hood compartment from the front of the vehicle as the fuel cell vehicle travels and / or the FC radiator fan 22 rotates, and passes through the air conditioner capacitor 20 and the FC radiator 21 in this order. Take heat away from them.

  The rotation speed of the FC cooling water pump 23 is controlled by a control signal from the cooling control device 15, and the cooling water is circulated through the cooling water circulation path 14. The water temperature sensor 28 is disposed at the exit location of the coolant circulation path 14 in the fuel cell stack 11 and detects the coolant temperature at the location. The temperature sensor 29 is disposed at a location where the hydrogen flow path of the reaction gas exits the fuel cell stack 11 and detects the temperature of hydrogen at that location. The temperature sensor 30 is disposed at a location where an air flow path containing oxygen as a reaction gas exits the fuel cell stack 11, and detects the temperature of air at the location.

  The electronic drive device 13 includes a power drive unit 36 in addition to the vehicle control unit 27 and the motor 37. The vehicle control unit 27 is connected to the power drive unit 36 via the power cable 35, distributes the electric power from the fuel cell stack 11 to the high voltage battery 12 and the power drive unit 36, and controls the distribution ratio. The power drive unit 36 drives the motor 37 with electric power supplied via the vehicle control unit 27.

  The voltage sensor 41 and the current sensor 42 detect the voltage and current in the power cable 33, respectively. The voltage sensor 45 and the current sensor 46 detect the voltage and current in the power cable 34, respectively. The voltage sensor 49 and the current sensor 50 detect the voltage and current in the power cable 35, respectively.

  The cooling control device 15 includes a motor output margin determination unit 55, an FC high temperature and high load determination unit 56, and a cooling promotion control unit 57. The cooling control device 15 receives detection signals from the water temperature sensor 28, the temperature sensor 29, the temperature sensor 30, the voltage sensors 41, 45, 49, the current sensors 42, 46, 50, and the like. The cooling control device 15 also sends control signals to the air conditioner condenser 20, the FC radiator 21, the FC radiator fan 22, the FC cooling water pump 23, and the vehicle control unit 27 to control them.

  The motor output margin determination unit 55 determines the output margin of the motor 37. The FC high temperature and high load determination unit 56 determines whether or not the fuel cell stack 11 is in a high temperature and high load continuous state. The cooling promotion control unit 57 controls the air conditioner capacitor 20, the FC radiator fan 22 and / or the FC cooling water pump 23 based on the determinations of the motor output margin determination unit 55 and the FC high temperature / high load determination unit 56, and the fuel cell. Control the cooling of the stack 11.

  Prior to the description of the specific operation of the cooling control device 15, the control of the cooling control device 15 will be schematically described with reference to FIG.

  In the graph of FIG. 2, the horizontal axis indicates the temperature of the cooling water of the fuel cell stack 11 detected by the water temperature sensor 28 (FC water temperature T), and the vertical axis indicates the output voltage of the fuel cell stack 11 detected by the voltage sensor 41 (FC voltage). V). The solid line indicates the upper limit output voltage of the fuel cell stack 11. A broken line shown below the solid line indicates a lower limit output voltage of the fuel cell stack 11. The upper and lower output voltages V of the fuel cell stack 11 change according to the FC water temperature T. V1 and V2 are 320V and 330V, for example.

  When the fuel cell stack 11 outputs the upper limit or lower limit output voltage at each FC water temperature T, the IFC (output current) is constant, and the IFC at the upper limit (eg, 300 A) is the lower limit. Greater than IFC. The output power of the fuel cell stack 11 is proportional to the output voltage V of the fuel cell stack 11.

  In FIG. 2, a normal travel range and a high speed travel or climbing travel range are defined. The normal travel range is T1 ≦ T ≦ T2. The high speed traveling or climbing traveling range is a range of T2 <T. T1 and T2 are, for example, 75 ° C and 85 ° C, respectively. The lower limit or upper limit FC voltage V of the fuel cell stack 11 remains flat with respect to changes in the FC water temperature T in the normal travel range, and rises as the FC water temperature T increases below the normal travel range. Above the normal travel range, it falls as the FC water temperature T rises.

  When the fuel cell vehicle is in a state of high speed traveling or climbing traveling, the required output to the motor 37 increases, and accordingly, the FC voltage V rises to its upper limit, and the fuel cell stack 11 has a normal traveling range in FIG. It becomes P1 in.

  When the fuel cell vehicle further continues high-speed traveling or climbing traveling, the FC water temperature T rises, and the fuel cell stack 11 moves from P1 in the normal traveling range in FIG. 2 to P2 in the high-speed traveling or climbing traveling range.

  After the fuel cell stack 11 moves to P2 in the high speed traveling or climbing traveling range, if the high speed traveling or climbing traveling state continues, the FC water temperature T continues to rise, exceeds T3, and the state of the fuel cell Moves to P3 in the wavy line extending horizontally from the right end of the flat portion of the solid line to the right. If no measures are taken in the state of P3, after a few minutes have passed since the transition to the state of P3, the upper limit FC voltage is the value of the upper limit FC voltage at T3 in the range where the FC water temperature T exceeds T3. The starting point falls to the right, and the state of the fuel cell moves to P4. As a result, the output of the motor 37 falls, making it difficult to continue high-speed traveling or climbing traveling.

  The cooling control device 15 avoids a decrease in the output power of the fuel cell stack 11 such as P4 by performing control corresponding to this. Specific control of the cooling control device 15 will be described with reference to FIGS.

  The fuel cell in the present invention corresponds to the fuel cell stack 11. The storage battery in the present invention corresponds to the high voltage battery 12. The cooling means in the present invention corresponds to the FC radiator 21, the FC radiator fan 22 or the FC cooling water pump 23. The temperature detecting means in the present invention corresponds to the water temperature sensor 28. The load state detection means in the present invention corresponds to the FC high temperature and high load determination unit 56. The upper limit output power calculation unit and the motor required power calculation unit in the present invention correspond to the motor output margin determination unit 55. The cooling promotion means in the present invention corresponds to the cooling promotion control unit 57.

  The first predetermined value for the fuel cell temperature in the present invention can be set to T2 or T3 in FIG. The second predetermined value for the fuel cell temperature in the present invention can also be set to T2 or T3 in FIG. The first and second predetermined values can be set to T2 and T3, respectively.

  In FIG. 3, the cooling control device 15 is activated when an ignition switch (not shown) of a fuel cell vehicle on which the fuel cell system 10 is mounted is turned on, that is, when the operation of the fuel cell vehicle is started. To do. The processing of ROUTINEs 60 and 61 realizes the functions of the motor output margin determination unit 55 and the FC high temperature and high load determination unit 56 of the cooling control device 15, respectively.

  In STEP 62, it is checked whether the judgment result in ROUTINE 60 is no margin or margin for the output of the motor 37. If there is no margin, the process proceeds to STEP 63. If there is a margin, STEP 65 is determined. Proceed to

  In STEP 63, it is checked whether the determination result in ROUTINE 61 is whether the fuel cell stack 11 is in the high temperature and high load continuation state. If the determination result is in the high temperature and high load continuation state, the process proceeds to ROUTINE 64. If it is determined that the high temperature / high load continuation state is not established, the process proceeds to STEP 65.

  The processing of ROUTINE 64 realizes the function of the cooling promotion control unit 57 of the cooling control device 15. ROUTINE 64 is executed when there is no margin for the output of the motor 37 and the fuel cell stack 11 is in the high temperature and high load continuing state, and is skipped at other times. Details of the ROUTINE 64 will be described later with reference to FIG.

  In STEP65, it is determined whether the ignition switch is off or on. If it is on, the routine returns to ROUTINE 60. If it is off, that is, when the operation of the fuel cell vehicle is finished, the operation of the cooling control device 15 is performed. Stop.

  FIG. 4 is a flowchart of ROUTINE 60 for determining the output margin of the motor 37. In STEP 601, output power (motor output) that the fuel cell stack 11 and the high-voltage battery 12 can jointly supply to the motor 37 at the present time. (Upper limit) is A, the upper limit (FC output upper limit) of the output power of the fuel cell stack 11 at present is A1, the upper limit (battery output upper limit) of the output power of the high voltage battery 12 is A2, and all except motor 37 The current power consumption of the electrical component is defined as A3, and A is calculated from the formula: A = A1 + A2-A3. A1 at this time corresponds to the output power (FC voltage × output current) of the fuel cell stack 11 at each position on the solid line in FIG. A2 at the present time remains substantially constant until the end of the discharge of the high-voltage battery 12, but decreases when it is about to end the discharge. A is electric power that the motor 37 can receive from the fuel cell stack 11 and the high voltage battery 12 at the present time.

  In STEP 602, A is compared with supply power (motor required power) that needs to be supplied to the motor 37 so that the motor 37 outputs the required output. If A ≦ motor required power, the process proceeds to STEP 603. If A> motor required power, go to STEP 604. The required output for the motor 37 corresponds to, for example, the depression amount of the accelerator pedal in the cab. The operator depresses the accelerator pedal as much as the motor 37 requires a larger output.

  Regarding the output of the motor 37, it is determined in STEP 603 that there is no margin, and in STEP 604, it is determined that there is a margin.

  FIG. 5 is a flowchart of the ROUTINE 61 for determining the high temperature and high load continuation state of the fuel cell stack 11. In STEP611, the timer is reset, and measurement of the elapsed time is started by the timer.

  In STEP612, the FC water temperature T is compared with a predetermined value B (for example, B ≦ T3 in FIG. 2 and a value near T3. For example, B = 90 ° C.). If the FC water temperature T> B, STEP613 If the FC water temperature T ≦ B, go to STEP 616.

  In STEP 613, the output power (or output current IFC) of the fuel cell stack 11 is compared with the predetermined value C. If the output power (or output current IFC)> C, the process proceeds to STEP 614 and the output power (or output current IFC) is determined. ) ≦ C, proceed to STEP 616. Note that in STEP 613, the output power of the fuel cell depends more on the output current IFC than the output voltage V, instead of using the output voltage V instead of the output power of the fuel cell stack 11. Because. When determining the load of the fuel cell stack 11 based on the output current IFC, C is, for example, 200 A or more if the solid line IFC in FIG.

  In STEP 614, it is determined whether or not the measurement time in the timer that started measuring the elapsed time in STEP 611 is equal to or longer than the predetermined time. If it is equal to or longer than the predetermined time, the process proceeds to STEP 615. Return.

  Regarding the temperature, load, and continuation state of the fuel cell stack 11, STEP 615 determines that the fuel cell stack 11 is in the high temperature and high load continuation state, and STEP 616 determines that the fuel cell stack 11 is in the normal state.

  In FIG. 6, (a) and (b) define two types of high temperature and high load state regions. (A) is a region of a high temperature and high load state employed in the ROUTINE 61 of FIG. In actual ROUTINE 61, the continuation (time factor) determination of STEP 614 is added as the high temperature and high load continuation state, but FIG. 6 shows only the region of the high temperature and high load state narrowed down in STEPs 612 and 613. In FIG. 6, the horizontal axis indicates the FC water temperature T, and the vertical axis indicates the output power (FC output) or output current (FC current) of the fuel cell stack 11.

  In FIG. 6 (a), the region where the FC water temperature T> B and the FC output> C is the high temperature and high load state region, and the other region is the normal state region of the fuel cell stack 11.

  In FIG. 6B, the boundary line L that separates the high temperature and high load state region and the normal state of the fuel cell stack 11 is defined by two inclined line portions having different inclination angles. That is, the two inclined line portions that define L are coupled at the location where the output power of the fuel cell stack 11 is equal to C, and the FC water temperature T at the coupling point is a value B ′ (B ′ <B) slightly smaller than B. It has become. Further, the decrease amount of the FC output with respect to the unit increase amount of the FC water temperature T is smaller on the right side than the coupling point from the left side.

  FIG. 7 is a flowchart of ROUTINE 64 related to the cooling promotion control of the fuel cell stack 11. In STEP 641, (a) the speed of the FC radiator fan 22 is increased, (b) the speed of the FC cooling water pump 23 is increased, and / or (c) the temperature adjustment amount of the air conditioner for adjusting the temperature of the passenger compartment is decreased. In (a) and (b), the flow rate of the cooling water of the fuel cell stack 11 increases, and as a result, cooling of the fuel cell stack 11 is promoted.

  In (c), due to the decrease in the temperature adjustment temperature amount of the air conditioner, the difference between the temperature of the cooling air W in the air conditioner condenser 20 and the temperature of the air conditioner condenser 20 is reduced, and the cooling air W passes through the air conditioner condenser 20. The temperature rise is suppressed, the low temperature is maintained, and the gas passes through the FC radiator 21. As a result, the amount of decrease in the coolant temperature in the FC radiator 21 increases, and the cooling of the fuel cell stack 11 is promoted.

  By promoting the cooling of the fuel cell stack 11 by the ROUTINE 64, the FC water temperature T becomes lower than B, and therefore lower than T3 (FIG. 2), and the output power of the fuel cell stack 11 increases. Note that the FC water temperature T after the decrease due to the implementation of ROUTINE 64 can be set to be lower than T3, for example, T2 (FIG. 2). By such a decrease in the FC water temperature T, the wet state of the electrodes of the fuel cell stack 11 is improved, and the output power of the fuel cell stack 11 increases.

When ROUTINE 64 is skipped in FIG. 3, the cooling capacity of the fuel cell stack 11 is lower by a predetermined amount than when ROUTINE 64 is executed.
Therefore, even if the motor 37 is in a state where there is no output margin and the fuel cell stack 11 is not in a high temperature and high load continuation state, for example, even if the fuel cell stack 11 is at a high temperature, the motor 37 The fuel cell stack 11 is cooled and consumed by a suitably low cooling power during a period in which a decrease in the output power of the fuel cell stack 11 is not a problem because there is a margin in output or the load on the fuel cell stack is not large. Power is suppressed.

  The fuel cell system of the present invention can also be applied to a fuel cell system mounted on a moving body such as a vehicle other than a fuel cell automobile or a ship.

  In the embodiment of the present invention, the required output for the motor is calculated based on the amount of depression of the accelerator pedal. In addition, when the traveling speed decreases even though the amount of depression of the accelerator pedal is equal to or greater than a predetermined value. It may be calculated based on the amount of decrease or the rate of decrease.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system, 11 ... Fuel cell stack, 12 ... High voltage battery, 14 ... Cooling water circuit, 15 ... Cooling control device, 20 ... Air-conditioner condenser, 21 ... FC radiator, 22 ... FC radiator fan, 23 ... FC cooling water pump, 28 ... Water temperature sensor, 37 ... Motor, 55 ... Motor output margin judgment unit, 56 ... FC high temperature and high load determination unit, 57... Cooling promotion unit.

Claims (7)

A motor,
A fuel cell that charges the storage battery and supplies power to the motor and other electrical components in cooperation with the storage battery;
Cooling means for cooling the fuel cell;
Temperature detecting means for detecting the temperature of the fuel cell;
Load state detection means for detecting the load state of the fuel cell;
Upper limit output power calculating means for calculating a current total upper limit output power obtained by summing the current upper limit output power of the fuel cell and the current upper limit output power of the storage battery;
Motor required power calculating means for calculating motor required power required for the motor to output the required output;
Based on the total upper limit output power, the motor required power, and the current supply power to the other electrical components, it is determined whether or not the motor output is in a non-margin state, and the fuel cell temperature, the fuel cell load, and the fuel It is determined whether or not the fuel cell is in a high-temperature and high-load continuation state based on the battery temperature and the duration of the predetermined state with respect to the fuel cell load. If it is a high temperature and high load continuation state, the cooling promotion means for increasing the cooling capacity of the cooling means and lowering the fuel cell temperature to a first predetermined value or less,
A fuel cell system comprising: The fuel cell system according to claim 1, wherein
The cooling promotion means determines that the motor output is in a non-exempt state when the sum of the motor required power and the current supply power to the other electrical components exceeds the total upper limit output power. A fuel cell system. The fuel cell system according to claim 1 or 2,
When the fuel cell temperature is equal to or higher than a second predetermined value that is equal to or higher than the first predetermined value and the fuel cell load is equal to or higher than a predetermined value, the cooling promoting means It is judged that it is a continuous state, The fuel cell system characterized by the above-mentioned. The fuel cell system according to any one of claims 1 to 3,
The refrigerant radiator for cooling the fuel cell is disposed adjacent to a refrigerant condenser of an air conditioner so as to be cooled by cooling air after passing through the condenser,
The fuel cell system according to claim 1, wherein the cooling promoting means increases the cooling capacity of the cooling means by reducing a temperature adjustment amount by the air conditioner. A fuel cell system mounted on a vehicle,
A motor for driving the drive wheels of the vehicle;
An electrical component mounted on the vehicle and excluding the motor;
A storage battery for supplying electric power to the motor and the electrical component;
A fuel cell for supplying electric power to the motor and the electrical component and charging the storage battery;
Temperature detecting means for detecting the temperature of the fuel cell;
A cooling pump for circulating a refrigerant for cooling the fuel cell in a circulation path;
A fuel cell radiator disposed in the circulation path;
A radiator fan that generates cooling air for cooling the fuel cell radiator;
A control device,
The controller is
And power that can be output at the present time from the previous SL fuel cell and the storage battery, and the required motor power required to produce an output that the motor is required, based on the power consumption of current of the electrical components, motor output Determining whether the fuel cell is in a predetermined high temperature and high load state based on the temperature of the fuel cell and the output of the fuel cell,
If it is determined that the motor output is in a marginal state and the predetermined high temperature and high load state continues for a predetermined time or more, the rotational speed of the cooling pump is increased or the rotational speed of the radiator fan is increased. A fuel cell system characterized by increasing. The fuel cell system according to claim 5, wherein
The fuel cell radiator is:
Adjacent to the refrigerant condenser of the air conditioner included in the electrical component, arranged to be cooled by the cooling air after passing through the refrigerant condenser,
If the control device determines that the motor output is in a non-surplus state and that the predetermined high temperature and high load state has continued for a predetermined time or longer, the fuel cell is removed from the predetermined high temperature and high load state. A fuel cell system, wherein the temperature adjustment amount of the air conditioner is reduced. A motor,
A fuel cell that charges the storage battery and supplies power to the motor and other electrical components in cooperation with the storage battery;
Cooling means for cooling the fuel cell;
A control method for a fuel cell system comprising:
A temperature detecting step for detecting the temperature of the fuel cell;
A load state detecting step for detecting a load state of the fuel cell;
An upper limit output power calculating step of calculating a current total upper limit output power obtained by summing the current upper limit output power of the fuel cell and the current upper limit output power of the storage battery;
A motor required power calculating step for calculating a motor required power required for the motor to output the requested output;
Based on the total upper limit output power, the motor required power, and the current supply power to the other electrical components, it is determined whether or not the motor output is in a non-margin state, and the fuel cell temperature, the fuel cell load, and the fuel It is determined whether or not the fuel cell is in a high-temperature and high-load continuation state based on the battery temperature and the duration of the predetermined state with respect to the fuel cell load. A cooling promotion step of increasing the cooling capacity of the cooling means to lower the fuel cell temperature to a first predetermined value or less if the high temperature and high load continuation state;
The control method characterized by including.

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