JP5272328B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system that cooperates with a vehicle compartment heating system.

  Each cell of the fuel cell is formed such that both sides of the electrolyte membrane are sandwiched between gas diffusion electrodes (fuel gas electrode (anode) and oxidant gas electrode (cathode)) and both sides are sandwiched between separators provided with gas supply paths. Is done. In each of such cells, the fuel cell reacts with the fuel gas supplied to the flow path provided on the anode side and the oxidant gas supplied to the flow path provided on the cathode side via the electrolyte membrane. To generate electricity.

  Heat is generated during the reaction between the oxidant gas and the fuel gas in each cell. If the cell becomes too hot due to this heat generation, the power generation efficiency of the fuel cell decreases due to drying of the electrolyte membrane or the like. Thus, a coolant circulation path is provided in the fuel cell system, and heat generated in each cell is transported outside the stack by the coolant supplied from this path into the fuel cell stack. The coolant heated in each cell exchanges heat with the atmosphere by a cooling means such as a radiator provided on the coolant circulation path.

  On the other hand, even when the operating temperature of each cell is low, the power generation efficiency of the fuel cell decreases due to, for example, freezing of water in each cell. Therefore, a method for efficiently warming up the fuel cell before starting operation has been proposed. Patent Document 1 below proposes a method of warming up a fuel cell before the start of operation together with air conditioning in a vehicle interior using a heat pump that is charged with the fuel cell and fed by the storage battery. Patent Document 2 below proposes a method of using circulating water heated in a predetermined fuel cell stack to warm up other fuel cell stacks in a plurality of fuel cell stacks.

  In addition, the following documents are disclosed as prior art documents related to the present invention.

Patent Document 3 listed below includes two fuel cells: a main fuel cell used for power generation of a drive motor of a vehicle and a sub fuel cell used for power generation of auxiliary equipment such as an air compressor and a vehicle electrical component. Vehicles to be installed have been proposed. The following Patent Document 4 includes a first fuel cell and a second fuel cell, and a method of driving auxiliary equipment such as a blower and a pump provided for the first fuel cell by the second fuel cell. Has been proposed. Patent Document 5 below proposes a technique for reducing the output voltage of a fuel cell at the time of stoppage or emergency without consuming power by switching the connection state between the fuel cell stacks with a relay or the like.
JP 2005-50638 A JP 2006-147597 A JP 2004-39524 A JP 2004-335376 A JP 2005-222864 A

  By the way, a technique for improving the energy efficiency of the entire fuel cell system, such as a method of effectively utilizing the exhaust heat of the fuel cell as proposed in Patent Document 2, has been studied. For example, in a vehicle that uses a fuel cell for power generation such as a drive motor, a method of using the exhaust heat of the fuel cell for vehicle compartment heating or the like can be considered. In this method, it is desirable to keep the exhaust heat of the fuel cell at a high temperature.

  However, it is difficult for the fuel cell system to keep the exhaust heat temperature of the fuel cell at a high temperature. The exhaust heat temperature of the fuel cell depends on the power generation amount, and this power generation amount fluctuates mainly by a request from a load device such as a drive motor.

  Therefore, in order to keep the exhaust heat temperature of the fuel cell system constant, a method of providing a strong heat insulation function or a method of continuing a predetermined amount of power generation can be considered.

  However, in the former method, it is difficult to provide a heat insulation function to the entire fuel cell system as a system. In the latter method, there is a concern about a decrease in energy efficiency such as a problem of a consumption destination of electric power output to keep the exhaust heat temperature at a high temperature.

  An object of the present invention is to provide a fuel cell system that allows a passenger compartment heating system to perform efficient heating while maintaining energy efficiency.

  The present invention employs the following means in order to solve the above-described problems. That is, the fuel cell system according to the present invention outputs a first fuel cell that supplies electric power to the motor for traveling, and electric power smaller than the first fuel cell, and supplies this output electric power to the vehicle interior heating device. A coolant circulation path for circulating a second fuel cell and a coolant for recovering heat in the second fuel cell to an indoor heat exchanger for exchanging heat with the air in the vehicle interior And a first coolant circulation path for sending the coolant sent from the second fuel cell as a heat medium.

  In the present invention, the first fuel cell and the second fuel cell are separately provided, the first fuel cell generates electric power for driving the traveling motor, and the second fuel cell generates the vehicle interior heating. Electric power for driving the passenger compartment heating device included in the system is generated. Further, the coolant circulated through the first coolant circulation path for cooling the second fuel cell is sent to the indoor heat exchanger in a state including the exhaust heat of the second fuel cell, and the vehicle Used for heat exchange with room air.

  Thus, according to the present invention, the efficient operation of the first fuel cell can be independently performed according to the required power of the traveling motor without depending on the passenger compartment heating system, and the second fuel The exhaust heat of the battery can be used in the passenger compartment heating system. Therefore, the fuel cell system according to the present invention can cause the passenger compartment heating system to perform efficient heating while maintaining energy efficiency.

  Furthermore, according to the present invention, the second fuel cell outputs a smaller electric power than the first fuel cell and supplies electric power for the passenger compartment heating system. By so doing, it is possible to realize a control device related to power generation of the second fuel cell with a simple configuration, and to reduce the size of the system.

  Preferably, in the present invention, the indoor heat after the first coolant circulation path exchanges heat in the heat exchanger between the coolant sent from the second fuel cell and the refrigerant heat-treated by the vehicle compartment heating device. A coolant circulation path formed to be sent to the exchanger and circulating a coolant for recovering the heat in the first fuel cell, and exchanges heat with the coolant sent from the second fuel cell. In order to achieve this, a second coolant circulation path for sending the coolant sent from the first fuel cell to the heat exchanger is further provided.

  In such a configuration, the coolant from the second fuel cell that is used as the heat medium of the indoor heat exchanger is heat-treated by the vehicle interior heating device that operates with the electric power output from the second fuel cell. Heat is exchanged with the coolant circulating in the first fuel cell together with the refrigerant.

  Therefore, according to such a configuration, both the output power and the exhaust heat from the second fuel cell can be efficiently used in the vehicle compartment heating system, and the exhaust heat of the first fuel cell is also used in the vehicle compartment. Can be used in heating systems. At this time, since the heating performance can be maintained by using the output power and the exhaust heat from the second fuel cell, the exhaust heat of the first fuel cell can be used preliminarily. . Therefore, it is not necessary to perform control for maintaining the exhaust heat temperature of the first fuel cell in order to ensure the heating performance.

  Furthermore, in the present invention, it is preferable that the temperature measuring means for measuring the coolant temperature in the second coolant circulation path and the first fuel cell among the paths included in the second coolant circulation path. A switching valve that switches between a path through which the coolant to be circulated passes through the heat exchanger and a path through which the coolant circulates around the heat exchanger, and the coolant measured by the temperature measuring means When the temperature is higher than a predetermined temperature, the switching valve is further configured to include a control unit that switches the coolant sent from the first fuel cell to circulate through the heat exchanger.

  In such a configuration, when the temperature of the coolant including the exhaust heat of the first fuel cell is higher than a predetermined temperature, the coolant from the first fuel cell is used as a heat medium for the indoor heat exchanger. It is used for heat exchange with the coolant from the second fuel cell.

  Therefore, according to such a configuration, the exhaust heat of the first fuel cell can be selectively used in the vehicle compartment heating system, so that more efficient heating can be performed.

  In the present invention, the second fuel cell may not need to consume all of the output power by the vehicle interior heating device depending on the exhaust heat temperature, vehicle interior temperature, and the like of the second fuel cell. As a method of consuming surplus power out of the power output from the second fuel cell in such a case, there is a method of consuming by control of, for example, a heat pump or an expansion valve that can be included in the vehicle interior heating device. . However, it can be said that such a consumption method does not effectively use the output power from the second fuel cell.

  Therefore, the present invention provides a connection point provided on a power line connecting the first fuel cell and the traveling motor, and a connection point provided on a power line connecting the second fuel cell and the vehicle interior heating device. A direct current / direct current (DC / DC) converter is further provided in the middle of the relay power line connecting the two.

  In such a configuration, the DC / DC converter controls so that the surplus power of the output power from the second fuel cell is used as necessary for driving the driving motor.

  Therefore, according to such a configuration, both the electric power output from the first fuel cell and the second fuel cell can be effectively used, and the energy efficiency can be improved.

  Furthermore, in such a configuration, it is preferable that power control means for controlling power passing through the DC / DC converter out of power output from the second fuel cell based on loss characteristics of the DC / DC converter is further provided. Configure as follows.

  According to such a configuration, it is possible to selectively use the output power from the second fuel cell so that the power loss is reduced in consideration of the loss characteristics of the DC / DC converter. Can be increased.

  Specifically, such power control means can be realized by the following configuration, for example.

  That is, the electric power control means is not consumed by the vehicle compartment heating device among the insufficient electric power to be supplied by the first fuel cell and the electric power output from the second fuel cell among the required electric power of the driving motor. By obtaining surplus power respectively, the passing power calculation means for calculating the power passing through the DC / DC converter and the passing power calculated by the passing power calculation means based on the loss characteristics of the DC / DC converter. Power consumption control means for controlling the power consumption of the passenger compartment heating device is provided so that power loss in the DC / DC converter does not increase.

  The power passing through the DC / DC converter calculated by the passing power calculation means may be configured to be measured by a current / voltmeter or the like, and the loss characteristics of the DC / DC converter are passed through. Information on the relationship between power and power loss may be stored in advance in a memory or the like.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which makes a vehicle interior heating system perform efficient heating can be provided, maintaining energy efficiency.

  Hereinafter, the fuel cell system of each embodiment of the present invention will be described with reference to the drawings. In addition, the structure of each embodiment described below is an illustration, respectively, and this invention is not limited to the structure of the following embodiment.

[First embodiment]
Hereinafter, a fuel cell system and a heat pump heating system (hereinafter also simply referred to as a heating system) as a first embodiment of the present invention will be described. Both the fuel cell system and the heating system as the first embodiment of the present invention are mounted on a vehicle such as an automobile.

〔System configuration〕
FIG. 1 is a diagram showing a configuration example of a fuel cell system and a heating system as a first embodiment of the present invention.

<Fuel cell system>
The fuel cell system according to the present embodiment includes a fuel cell main stack (hereinafter referred to as main FC) 21, a fuel cell sub stack (hereinafter referred to as sub FC) 22, air compressors 24 and 25, a regulator 23, and pressure adjustment. A valve 26, a temperature sensor 28, a three-way valve 29, an ECU (Electric Control Unit) 51 for the main FC 21 (hereinafter referred to as a main ECU) 51, an ECU for the sub FC 22 (hereinafter referred to as a sub ECU) 52, and the like. .

  The fuel cell system according to the present embodiment includes a main FC 21 (corresponding to the first fuel cell of the present invention) that supplies power to a load device such as a travel drive motor 20 for obtaining a driving force of a vehicle, Sub-FC22 (equivalent to the 2nd fuel cell of this invention) which supplies the electric power to load apparatuses, such as the heat pump which comprises the heating system in embodiment, is provided.

The main FC 21 and the sub FC 22 sandwich an electrolyte membrane between a fuel gas electrode (hereinafter referred to as an anode) and an oxidant gas electrode (hereinafter referred to as a cathode), and further, gas supply paths are provided on both sides of these electrodes. Each cell stack includes a predetermined number of cells formed so as to be sandwiched between separators. The main FC 21 and the sub FC 22 are fuel gas inlets,
Each has a fuel gas outlet, an oxidant gas inlet, an oxidant gas outlet, a coolant inlet, and a coolant outlet.

  A fuel gas (for example, hydrogen gas) sent from a fuel gas tank (not shown) or the like and pressure-adjusted by the regulator 23 passes through the pipe 61 and flows into the main FC 21 and the sub FC 22 from the fuel gas inlet. Each is supplied to the anode. On the other hand, an oxidant gas (for example, compressed air) taken from the atmosphere via an air filter or the like and compressed by the air compressor 24 passes through the pipe 62 and flows into the main FC 21 from the oxidant gas inlet, Supplied to the cathode. Similarly, the oxidant gas compressed by the air compressor 25 passes through the pipe 63, flows into the sub FC 22 from the oxidant gas inlet, and is supplied to the cathode of each cell.

  The main FC 21 and the sub FC 22 generate power by reacting the fuel gas and the oxidant gas supplied in this way through the electrolyte membrane in each cell. Fuel gas that has not been used for power generation (hereinafter referred to as anode offgas) is discharged from the fuel gas outlet, and oxidant gas that has not been used for power generation (hereinafter referred to as cathode offgas) is discharged from the oxidant gas outlet. Is done. The pressure regulating valves 26 and 27 are respectively arranged in pipes connected to the oxidant gas outlets of the main FC 21 and the sub FC 22 and adjust the back pressure of the oxidant gas.

  The present invention limits the oxidant gas supply method, cathode off-gas discharge method, fuel gas supply method, anode off-gas discharge method, and power generation amount control method in the main FC 21 and the sub FC 22 as described above. is not. Therefore, a circulation path for the fuel gas may be provided, and another control device may be provided in each path.

  The main FC 21 is connected in parallel to the inverter 19 together with the storage battery 71. As a result, the DC voltage supplied by the main FC 21 is applied to the storage battery 71 and the inverter 19. The inverter 19 converts the DC power supplied from the main FC 21 into three-phase AC power and sends it to the drive motor 20. The drive motor 20 rotates the wheel shaft with this AC power. The electric power generated by the main FC 21 is mainly used as a power source for the drive motor 20. The storage battery 71 is, for example, a secondary battery, and charges the power output from the main FC 21 and discharges the charged power. The present invention does not limit the presence or absence of the storage battery 71 nor limit the load device of the main FC 21 to the travel drive motor 20.

  Further, a direct current / direct current (DC / DC) converter (hereinafter simply referred to as a converter or DC / DC) 72 is connected between a power line connecting the main FC 21 and the inverter 19 and a power line connecting the storage battery 71 and the inverter 19. Is done. The converter 72 operates as a step-up / down voltage converter, and performs control of power supply from the main FC 21 to the storage battery 71, control of an output power ratio of the main FC 21 and the storage battery 55 to the inverter 19, and the like.

  The main FC 21 is controlled by the main ECU 51 so that electric power corresponding to the required electric energy from the drive motor 20 is generated. The main ECU 51 controls the regulator 23, the air compressor 24, the pressure adjustment valve 26, and the like in order to control the power generation amount of the main FC 21.

  The sub FC 22 is connected via an inverter 32 to a drive motor 31 for a heat pump used in a heating system described later. The electric power generated by the sub FC 22 is used as a power source for the heat pump drive motor 31. The inverter 32 converts the DC power supplied from the sub FC 22 into three-phase AC power and sends it to the motor 31.

Since the sub FC 22 is intended to supply power to the heating system in the present embodiment, the sub FC 22 is configured to generate power smaller than the output power of the main FC 21. This can be realized by making at least one of the number of cells and the cell area of the sub FC 22 smaller (smaller) than that of the main FC 21, so that the sub FC 22 itself can be downsized.

  For this purpose, the sub FC 22 is operated substantially in a steady state so that a predetermined target power amount may be generated. Therefore, the control for the air compressor 25, the pressure regulating valve 27, and the like for adjusting the power generation amount of the sub FC 22 only needs to be controlled so that the power generation amount of the sub FC 22 becomes the target power amount. can do. However, such an advantage may be discarded and the power generation amount of the sub FC 22 may be controlled according to the required power of the load device. In addition, sub FC22 may be comprised so that the electric power to load apparatuses other than the heat pump which comprises a heating system may be supplied.

  Further, the main FC 21 and the sub FC 22 are each provided with a circulation path for a cooling liquid such as cooling water in order to prevent the stack itself from becoming high temperature due to heat generated during power generation. The heat generated in each cell by the coolant supplied from the circulation path into each fuel cell stack is transported to the outside of each fuel cell stack. The coolant circulation path of the main FC 21 corresponds to the second coolant circulation path of the present invention, and the coolant circulation path of the sub FC 22 corresponds to the first coolant circulation path of the present invention.

  The coolant circulation path of the main FC 21 is connected via a pipe 1 connected to a coolant outlet from which the coolant circulating inside the main FC 21 is discharged, a pipe 3 branched from the pipe 1, pipes 1 and 3, and a three-way valve 29. The pipe 2 is configured to re-feed the coolant into the fuel cell. Here, the heat exchanger 30 which comprises the heating system mentioned later is installed in the piping 1 until it connects with the three-way valve 29 after branching with the piping 3.

  Furthermore, a temperature sensor 28 is provided in the pipe 1 near the coolant outlet of the main FC 21 in the coolant circulation path of the main FC 21. This temperature sensor 28 corresponds to the temperature measuring means of the present invention, measures the temperature of the coolant, and sends the measurement result to the main ECU 51.

  The three-way valve 29 has a port through which the coolant that has passed through the heat exchanger 30 flows in from the pipe 1, a port through which the coolant discharged from the coolant outlet of the main FC 21 flows in from the pipe 3, and a pipe for connecting the coolant that flows in 2 to the mouth. The three-way valve 29 corresponds to the switching valve of the present invention, and the main ECU 51 controls the opening and closing of these inlet and outlet. Thereby, whether the coolant discharged from the main FC 21 is re-supplied to the main FC 21 through the heat exchanger 30 or is re-supplied to the main FC 21 via the pipe 3 without passing through the heat exchanger 30. Is switched.

The main ECU 51 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like, and performs flow path control in the coolant circulation path of the main FC 21 by the CPU executing a control program stored in the memory. . The main ECU 51 corresponds to the control means of the present invention. Specifically, the main ECU 51 performs coolant flow path control as follows. When the main ECU 51 determines that the coolant is higher than the predetermined threshold temperature based on the output from the temperature sensor 28, the main ECU 51 controls the three-way valve 29 so that the coolant passes through the heat exchanger 30 and circulates. Conversely, when the main ECU 51 determines that the coolant is lower than the predetermined threshold temperature, the main ECU 51 controls the three-way valve 29 so that the coolant circulates without passing through the heat exchanger 30. By such control, the exhaust heat of the main FC 21 is effectively used in the heating system.

On the other hand, the coolant circulation path of the sub FC 22 is connected to the coolant outlet from which the coolant circulated inside the sub FC 22 is discharged, and the piping 4 that sends the coolant to the heat exchanger 30 and the cooling that has passed through the heat exchanger 30. The pipe 5 is configured to send out the liquid and send the cooling liquid to the evaporator 40, and the pipe 6 is supplied with the cooling liquid that has passed through the evaporator 40 and re-supplied the cooling liquid into the sub FC 22. With such a configuration, the coolant circulating in the coolant circulation path of the sub FC 22 is used not only as a cooling medium for the sub FC 22 itself, but also as a heat medium for transferring heat to the passenger compartment space. With such a configuration, the exhaust heat of the sub FC 22 is effectively used in the heating system. Details of the coolant circulation path of the sub FC 22 will be described later.

<Heating system>
The heating system in the present embodiment includes a heat exchanger 30, a motor 31 and a compressor 33 constituting a heat pump, an external heat exchanger 35, three-way valves 36 and 38, expansion valves 37 and 39, an evaporator 40, a flap 41, a sub ECU 52, and the like. Is provided.

The heating system in the present embodiment has a refrigerant circulation path through which a refrigerant such as CO ₂ is circulated. The refrigerant circulating in this refrigerant circulation path exchanges heat with the coolant circulating in the coolant circulation path of the sub FC 22 in the heat exchanger 30 together with the coolant circulating in the coolant circulation path of the main FC 21. Hereinafter, each apparatus which comprises the refrigerant | coolant circulation path with which the heating system in this embodiment is provided is each demonstrated.

  The heat pump corresponds to the passenger compartment heating device of the present invention, and includes a compressor 33, a motor 31, and the like. In the heat pump, the motor 31 is driven by the electric power generated by the sub FC 22, and the compressor 33 is operated by the power of the motor 31.

  When the heat pump is controlled so that the refrigerant that has passed through the external heat exchanger 35 is sent directly to the heat pump by the three-way valve 36, the heat pump receives the refrigerant that has passed through the external heat exchanger 35 from the pipe 12. On the other hand, when the refrigerant that has passed through the external heat exchanger 35 by the three-way valve 36 is controlled to pass through the expansion valve 39 and the heat exchanger 30, the heat pump removes the refrigerant that has passed through the heat exchanger 30. Receive via pipes 11 and 12. The heat pump compresses the refrigerant sent in this way by the compressor 33 and sends it out. The rotation speed of the heat pump is controlled by the sub ECU 52. The refrigerant compressed by the heat pump is sent to the pipe 13.

  The three-way valve 38 has a port through which the refrigerant compressed by the heat pump flows in from the pipe 13, a port through which the refrigerant that has flowed in is sent out to the pipe 14, and a port through which the refrigerant that has flowed in is sent out to the pipe 15. The three-way valve 38 is controlled by the sub ECU 52 to open and close these inlet and outlet. Thereby, it is switched whether the refrigerant passes through the heat exchanger 30 via the pipe 14 or circulates without passing through the heat exchanger 30 via the pipe 15. The refrigerant sent out to the pipe 14 exchanges heat with the coolant circulating in the sub FC 22 in the heat exchanger 30 and then is sent into the expansion valve 37. On the other hand, the refrigerant flowing through the pipe 15 is then fed into the pipe 7.

  The expansion valve 37 is installed between the pipe 14 and the pipe 7 through which the refrigerant that has passed through the heat exchanger 30 passes. The expansion valve 37 decompresses the refrigerant that has been heat-exchanged by the heat exchanger 30 and sent. The refrigerant decompressed by the expansion valve 37 is sent out to the pipe 7.

  The external heat exchanger 35 is installed between the pipe 7 and the pipe 8. The external heat exchanger 35 receives the refrigerant depressurized by the expansion valve 37 from the pipe 7 when the three-way valve 38 controls the refrigerant to pass through the heat exchanger 30. On the other hand, when the refrigerant is controlled so that the refrigerant does not pass through the heat exchanger 30 by the three-way valve 38, the external heat exchanger 35 receives the refrigerant pressurized by the heat pump from the pipe 7 via the pipe 15. . The external heat exchanger 35 exchanges heat between the refrigerant and the outside air. The refrigerant that has become substantially equal to the outside air temperature by heat exchange with the outside air is sent out to the pipe 8.

  The three-way valve 36 has a port through which the refrigerant that has become substantially equal to the outside air temperature through heat exchange with the outside air flows from the pipe 8, a port that sends out the flowing refrigerant to the pipe 9, and the refrigerant that has flowed into the pipe 12. And a delivery port. The three-way valve 36 is controlled by the sub ECU 52 to open and close these inlet and outlet. That is, the three-way valve 36 sends the refrigerant to the pipe 12 so that the refrigerant is sent to the heat pump as it is, or pipes the refrigerant so that the refrigerant is sent to the heat pump via the expansion valve 39 and the heat exchanger 30. Switch to send to.

  The expansion valve 39 is installed between the pipe 9 and the pipe 10. The expansion valve 39 receives the refrigerant having a temperature substantially equal to the outside air temperature from the pipe 9 and depressurizes the refrigerant. The refrigerant decompressed by the expansion valve 39 is sent out to the pipe 10. The refrigerant decompressed by the expansion valve 39 passes through the pipe 10 and is sent to the heat exchanger 30. The refrigerant exchanges heat with the coolant circulating in the sub FC 22 in the heat exchanger 30 and is sent out to the pipe 11. The refrigerant sent to the pipe 11 is sent to the heat pump via the pipe 112.

  The refrigerant circulation path generally includes a heating circulation path and a cooling circulation path. Of course, the heating circulation path and the cooling circulation path may act together.

  Here, the heating circulation path is a path through which the refrigerant sent to the heat exchanger 30 is circulated so as to be higher than the outside air temperature, and the three-way valve 38 is controlled so as to send more refrigerant to the pipe 14. The three-way valve 36 is controlled to send more refrigerant to the pipe 12. Thus, the refrigerant is circulated in the heating circulation path as follows. The refrigerant decompressed by the expansion valve 37 is brought to a temperature substantially equal to the outside air temperature by the external heat exchanger 35, and then pressurized by a heat pump. Therefore, the refrigerant sent from the heat pump and sent to the heat exchanger 30 is in a high pressure state and a temperature higher than the outside air temperature.

  On the other hand, the cooling circulation path is a path through which the refrigerant sent to the heat exchanger 30 is circulated so as to be lower than the outside air temperature, and is controlled so that the three-way valve 38 sends more refrigerant to the pipe 15. The three-way valve 36 is controlled to send more refrigerant to the pipe 9. Thus, the refrigerant is circulated in the cooling circulation path as follows. The refrigerant pressurized by the heat pump is brought to a temperature substantially equal to the outside air temperature by the external heat exchanger 35, and then depressurized by the expansion valve 39. Therefore, the refrigerant sent from the expansion valve 39 and sent to the heat exchanger 30 is in a low pressure state and a temperature lower than the outside air temperature.

  The heat exchanger 30 corresponds to the heat exchanger of the present invention, and is cooled in the sub FC 22 to recover the exhaust heat of the main FC 21 and send it to the coolant fed from the pipe 1 and the coolant circulating in the above-described coolant circulation path. Heat exchange with liquid. The coolant circulated in the sub FC 22 that has been heat-exchanged with the refrigerant or the like by the heat exchanger 30 and is heated is sent to the evaporator 40.

  The evaporator 40 corresponds to the indoor heat exchanger of the present invention, and is installed between the pipe 5 and the pipe 6 constituting the coolant circulation path of the sub FC 22. The evaporator 40 receives the coolant circulating in the coolant circulation path of the sub FC 22 from the pipe 5 and exchanges heat between the coolant and the air in the vehicle compartment.

  The flap 41 adjusts the amount of air passing through the evaporator 40. If the amount of air passing through the evaporator 40 increases due to the opening of the flap 41, the amount of air to be heat-exchanged increases, and if the amount of air passing through the evaporator 40 decreases, the amount of air to be heat-exchanged decreases. The opening degree of the flap 41 is controlled by the sub ECU 52.

The sub ECU 52 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like. The CPU controls the heating system according to the present embodiment by executing a control program stored in the memory. Specifically, for example, the sub ECU 52 has measured values from a discharge temperature sensor (not shown) that measures the discharge temperature from the evaporator 40, an indoor temperature sensor (not shown) that measures the vehicle interior temperature, and the like. A discharge temperature target value is determined based on the indoor set temperature or the like. The sub ECU 52 controls the three-way valves 36 and 38, the rotation speed of the heat pump, the opening degree of the flap 41, and the like so that the measured value of the discharge temperature sensor becomes the discharge temperature target value. The sub ECU 52 corresponds to a power control unit, a passing power calculation unit, and a power consumption control unit of the present invention. In addition, since this invention does not limit the control method of the heating system by sub ECU52, description is abbreviate | omitted about the detail of a control method.

[Operation and effect of the first embodiment]
Hereinafter, the operation and effect of the fuel cell system and the heating system as the first embodiment will be described.

  In the fuel cell system according to the present embodiment, the main FC 21 supplies power to a load device such as the drive motor 20 for rotating the wheels of the vehicle, and the sub FC 22 supplies power to the load device constituting the heating system. To do.

  Thereby, the main FC 21 serving as the power source of the vehicle is controlled by the main ECU 51 so as to generate electric power according to the required power generation amount of the drive motor 20 regardless of the control state of the heating system. On the other hand, the sub FC 22 supplies a predetermined target power amount by steady operation as a power source of the motor 31 in the heat pump constituting the heating system.

  Therefore, according to the fuel cell system in the present embodiment, the main FC 21 that supplies electric power as a power source of the vehicle and the sub FC 22 that supplies electric power as the power source of the heating system operate independently. It is possible to efficiently generate power for the load device in charge.

  Further, the sub FC 22 only needs to perform steady power generation capable of generating the target power amount, and the control to the air compressor or the like related to the power generation amount of the sub FC 22 can be simplified. This can be realized with a simple configuration.

  Here, the heat pump operated by the electric power supplied from the sub FC 22 generates heat by compressing the refrigerant in the refrigerant circulation path constituting the heating system in the present embodiment. The refrigerant heat-treated by the heat pump is sent to the heat exchanger 30.

  In the fuel cell system in the present embodiment, the heat exchanger 30 and the evaporator 40 constituting the heating system in the present embodiment are provided in the coolant circulation path for cooling the heat of the sub FC 22 itself, thereby circulating the sub FC 22. The cooling liquid to be used is also used as a heat medium for carrying heat to the air-conditioned space. As a result, the coolant that has recovered the exhaust heat in the sub FC 22 is further heated by exchanging heat with the refrigerant by the heat exchanger 30, and exchanges heat with the air in the vehicle interior by the evaporator 40.

  The heating system in the present embodiment uses the heat generated by the action of the heat pump that is operated by the electric power generated by the sub FC 22 and the exhaust heat of the sub FC 22 in the heating system, so that it is efficient with high energy efficiency. Heat up.

Furthermore, the coolant that is circulated to cool the heat of the main FC 21 itself is also the main ECU 51.
When it is determined that the coolant temperature is higher than a predetermined temperature, the heat is sent to the heat exchanger 30. Thereby, in the heat exchanger 30, the coolant circulating through the main FC 21 together with the refrigerant selectively exchanges heat with the coolant of the sub FC 22 that transports heat to the air-conditioned space.

  Therefore, according to the heating system in the present embodiment, the exhaust heat of the main FC 21 is further effectively used, and heating can be performed efficiently with high energy efficiency.

[Second Embodiment]
Hereinafter, a fuel cell system and a heat pump heating system (hereinafter also simply referred to as a heating system) as a second embodiment of the present invention will be described.

  In the fuel cell system and the heating system in the first embodiment described above, the receiving destination of the electric power generated by the sub FC 22 is mainly the heat pump. Therefore, when the electric power generated by the sub FC 22 is excessive for the heating system. In response to this, the efficiency of heat control in the heating system is lowered by opening / closing control of the three-way valves 38 and 36. That is, while the rotation speed of the heat pump is increased, the above-described heating circulation path and the cooling circulation path are operated together, and as a result, the vehicle interior temperature is controlled to be the set temperature. This is realized by the heating system of the first embodiment having a configuration in which the pipes 10 and 11 of the refrigerant cooling circulation path and the refrigerant heating circulation pipe 14 are both connected to the heat exchanger 30. It had been.

  However, in such control, it cannot be said that the electric power generated by the sub FC 22 is effectively used, and energy loss has occurred. Therefore, in the fuel cell system as the second embodiment of the present invention, energy loss is reduced by transferring the power generated by the sub FC 22 to the load device of the main FC 21.

〔System configuration〕
FIG. 2 is a diagram showing a configuration example of a fuel cell system and a heating system as a second embodiment of the present invention.

<Fuel cell system>
In the fuel cell system as the second embodiment, a converter 75 is connected between a connection point 81 provided on a power line connecting the main FC 21 and the inverter 19 and a connection point 82 provided on a power line connecting the sub FC 22 and the inverter 32. Connect with a relay power line via That is, the main FC 21 and the sub FC 22 are connected in parallel to the inverter 19. The converter 75 controls the output ratio between the output power from the main FC 21 and the output power from the sub FC 22. Converter 72 controls the output ratio between the output of storage battery 71 (input during charging) and the total output between main FC 21 and sub FC 22 controlled by converter 75.

  With such a configuration, the electric power output from the sub FC 22 and not consumed by the heating system (hereinafter referred to as surplus electric power of the sub FC 22) can be consumed by the inverter 19 (drive motor 20). it can.

<Heating system>
In the heating system according to the present embodiment, since the surplus power of the sub FC 22 is consumed by the drive motor 20 in the above-described fuel cell system, the configuration for consuming the surplus power of the sub FC 22 can be eliminated. That is, the heating system in the present embodiment includes a configuration in which only the piping 14 of the refrigerant circulation path is connected to the heat exchanger 30 and the refrigerant cooling circulation path is connected to the cooling evaporator 46.

  Therefore, the heating system in the second embodiment further includes a heating evaporator 45 and a cooling evaporator 46 with respect to the heating system of the first embodiment. And 11 are connected. By further including the cooling evaporator 46 as described above, dehumidifying heating can be realized in the heating system according to the second embodiment. In addition, about the other function part which comprises this heating system, since it is the same as that of 1st embodiment, description is abbreviate | omitted here.

[Control by ECU]
Furthermore, the fuel cell system as the second embodiment may be configured such that the surplus power of the sub FC 22 is selectively used by the drive motor 20 in consideration of the characteristics of the converter 75. Some converters 75 have such characteristics that when the passing power exceeds a predetermined power, the rate of increase in power loss increases and the energy efficiency decreases. The fuel cell system in the second embodiment controls the main ECU 51, the sub FC 22, and the heating system that control the main FC 21 in order to reduce the power loss in the converter 75 and realize a more energy efficient system. The sub ECU 52 is linked.

  In the second embodiment, the main ECU 51 and the sub ECU 52 are controlled as follows.

  The main ECU 51 acquires the required power of the drive motor 20, the state of charge of the storage battery 71, the amount of power generated by the main FC 21, and the like. , Expressed as insufficient power of the main FC 21). The required power of the drive motor 20, the state of charge of the storage battery 71, and the amount of power generated by the main FC 21 may be measured by a sensor or the like (not shown) and sent to the main ECU 51. The main ECU 51 sends information related to the insufficient power of the main FC 21 to the sub ECU 52.

  The sub ECU 52 calculates the power consumption of the heat pump by obtaining the measured value of the rotation number of the heat pump. The sub ECU 52 further obtains the power generation amount of the sub FC 22. The power generation amount of the sub FC 22 may be measured by a power meter (not shown) or the like, or the target power amount may be held in advance because the sub FC 22 is in steady power generation. The sub ECU 52 calculates the surplus power of the sub FC 22 by subtracting the power consumption of the heat pump from the power generation amount of the sub FC 22.

  The sub ECU 52 calculates the power passing from the sub FC 22 side to the main FC 21 side from the surplus power of the sub FC 22 and the insufficient power of the main FC 21 sent from the main ECU 51.

  Sub-ECU 52 holds data relating to the loss characteristics of converter 75 in a memory or the like. The data relating to the loss characteristics of the converter 75 is, for example, a relative table of passing power and power loss. Thereby, sub-ECU 52 determines whether or not the passing power calculated as described above becomes power that lowers energy efficiency (increases power loss) in converter 75. If sub-ECU 52 determines that the electric power is an amount of electric power that lowers energy efficiency (increases electric power loss) in converter 75 by this determination, control is performed to increase the rotation speed of the heat pump.

  By such control, when the power loss increases according to the power passing from the sub FC 22 to the converter 75, the heating system is controlled to consume surplus power. Thus, both the power generated by the main FC 21 and the power generated by the sub FC 22 can be effectively used as the entire system while taking into account the energy loss due to the converter 75, and as a result, the energy loss can be reduced as a whole system. Can do.

  It should be noted that a watt-hour meter that measures the power passing through the converter 75 is installed on the relay power line, and the sub ECU 52 may control the power consumption in the heating system in accordance with the measured passing power. .

[Operation and effect of the second embodiment]
Hereinafter, the operation and effect of the fuel cell system and the heating system as the second embodiment described above will be described.

  In the fuel cell system according to the second embodiment, a relay power line is provided to the inverter 19 connected to the traveling drive motor 20 so that the main FC 21 and the sub FC 22 are connected in parallel via the converter 75. Under the control of the converter 75, surplus power that is not consumed by the heating system among the power generated by the sub FC 22 is supplied to the inverter 19 as necessary, and is used as a power source for the travel drive motor 20.

  Therefore, according to the fuel cell system of the present embodiment, even when it is not necessary to consume all of the output power of the sub-FC 22 in the heating system, such as in the middle of spring or autumn, each output that is output from the main FC 21 and the sub-FC 22 Both electric power can be used effectively and energy efficiency can be improved.

  Furthermore, in the fuel cell system and the heating system in the second embodiment, the sub ECU 52 controls the power passing through the converter 75 out of the power output from the sub FC 22 based on the loss characteristics of the converter 75.

  That is, the main ECU 51 calculates the insufficient power of the main FC 21 out of the required power of the drive motor 20, and notifies the sub ECU 52 of information related to the insufficient power. In the sub ECU 52, for example, the power consumption of the heat pump based on the rotation number of the heat pump is calculated as the power consumption of the heating system, and the surplus power of the sub FC 22 is calculated from the power consumption of the heating system and the power generation amount of the sub FC 22.

  In the sub ECU 52, the passing power passing through the capacitor 75 is acquired from the surplus power of the sub FC 22 and the insufficient power of the main FC 21, and the passing power is compared with the loss characteristic of the capacitor 75 held in a memory or the like. The power loss at 75 is determined. The sub ECU 52 controls power consumption in the heating system so as to control the passing power so that the power loss does not increase.

  As a result, the output power from the sub FC 22 can be selectively used so that the power loss is reduced in consideration of the loss characteristics of the converter 75, so that the energy efficiency can be further improved.

[Modification]
In the fuel cell systems as the first embodiment and the second embodiment described above, the main FC 21 is a power source for the travel drive motor 20 and the sub FC 22 is a power source for the heating system. The same effect can be obtained even if the power generation device other than the fuel cell is provided instead of the FC 21.

FIG. 3 is a diagram illustrating a configuration example of a fuel cell system and a heating system as a modification of the first embodiment. According to FIG. 3, an engine 91 or the like is provided instead of the main FC 21 of the fuel cell system in the first embodiment. The engine 91 is a gasoline engine, a hydrogen engine, or the like. The engine 91 burns these fuels to obtain power, and drives wheels and the like with the obtained power. When the engine 91 is a hydrogen engine, the hydrogen gas may be supplied to the engine 91 by branching from a hydrogen gas supply path as a fuel gas supplied to the sub FC 22.

  In such a configuration, the same effect as in the first embodiment can be obtained by selectively sending a cooling medium for cooling the power generation device such as the engine 91 to the heat exchanger 30.

  FIG. 4 is a diagram illustrating a configuration example of a fuel cell system and a heating system as a modification of the second embodiment. According to FIG. 4, an engine 91 or the like is provided instead of the main FC 21 of the fuel cell system in the second embodiment. In this modification, a relay power line is provided that connects a connection point 82 provided on a power line extending from the sub FC 22 to the heat pump drive motor 31 to a power line connection point 81 extending from the storage battery 71 to the inverter 19. Thereby, the storage battery 71 and the sub FC 22 are connected in parallel to the inverter 19 via the converter 72.

  Therefore, the converter 72 is controlled so that the surplus power of the sub FC 22 is selectively used by the travel drive motor 20, so that the same effect as in the third embodiment described above can be obtained.

It is a figure which shows the structural example of the fuel cell system and heating system as 1st embodiment of this invention. It is a figure which shows the structural example of the fuel cell system and heating system as 2nd embodiment of this invention. It is a figure which shows the structural example of the fuel cell system as a modification of 1st embodiment, and a heating system. It is a figure which shows the structural example of the fuel cell system and heating system as a modification of 2nd embodiment.

Explanation of symbols

19, 32 Inverter 20 Traveling drive motor 21 Fuel cell main stack (main FC)
22 Fuel cell sub stack (sub FC)
28 Temperature sensor 29 Three-way valve 30 Heat exchanger 31 Heat pump drive motor 33 Compressor 35 External heat exchanger 36, 38 Three-way valve 37, 39 Expansion valve 40 Evaporator 45 Heating evaporator 46 Cooling evaporator 51 ECU for main FC 21 (Electric Control Unit) (Main ECU)
52 ECU for sub FC22 (sub ECU)
71 Storage batteries 72, 75 Direct current / direct current (DC / DC) converters 81, 82 Power line connection point 91 Engine (power generation device)

Claims (5)

A first fuel cell for supplying electric power to the traveling motor;
A second fuel cell that outputs less power than the first fuel cell and supplies the output power to the passenger compartment heating device;
A coolant circulation path for circulating a coolant for recovering heat in the second fuel cell, from the second fuel cell to an indoor heat exchanger for exchanging heat with the vehicle interior air A first coolant circulation path for sending the coolant to be sent out as a heat medium , wherein the coolant sent from the second fuel cell is heated in the heat exchanger and the refrigerant heat-treated by the vehicle compartment heating device. A first coolant circulation path for sending the coolant to the indoor heat exchanger after the replacement;
A coolant circulation path for circulating a coolant for recovering heat in the first fuel cell, wherein the first fuel cell exchanges heat with the coolant sent from the second fuel cell. A second coolant circulation path for sending coolant sent from the fuel cell to the heat exchanger ;
A fuel cell system comprising: Temperature measuring means for measuring a coolant temperature in the second coolant circulation path;
Of the paths included in the second coolant circulation path, a path through which the coolant sent from the first fuel cell circulates through the heat exchanger and the coolant bypasses the heat exchanger. And a switching valve that switches between circulating paths,
When the coolant temperature measured by the temperature measuring means is higher than a predetermined temperature, the switching valve is switched so that the coolant sent from the first fuel cell circulates through the heat exchanger. Control means;
The fuel cell system according to claim 1 , further comprising: A connection point provided on a power line connecting the first fuel cell and the traveling motor is connected to a connection point provided on a power line connecting the second fuel cell and the passenger compartment heating device. the fuel cell system according to claim 1 or 2 further comprising a DC-DC converter in the middle of the relay power line. 4. The fuel cell according to claim 3 , further comprising power control means for controlling power passing through the DC / DC converter among power output from the second fuel cell based on a loss characteristic of the DC / DC converter. 5. system. The power control means includes
Of the required power of the travel motor, the insufficient power to be supplied by the first fuel cell and the surplus power that is not consumed by the vehicle compartment heating device among the power output from the second fuel cell, respectively. By obtaining a passing power calculation means for calculating the power passing through the DC / DC converter,
Based on the loss characteristics of the DC / DC converter, the power consumption for controlling the power consumption in the passenger compartment heating device so that the power loss in the DC / DC converter of the passing power calculated by the passing power calculation means does not increase. Control means;
The fuel cell system according to claim 4 , comprising:

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