System for cooling fuel cell

Abstract

To provide technique that reduces the power consumption of a heater.SOLUTION: A system for cooling a fuel cell comprises a first cooling flow path, a fuel cell, a second cooling flow path, a radiator, a heater, a heater core, and an intermediate heat exchanger. The second cooling flow path comprises a bypass flow path arranged in parallel with the radiator. During power generation performed a fuel cell, first operation is performed in which refrigerant is circulated through the first cooling flow path via a path through the fuel cell and the intermediate heat exchanger, and the refrigerant is circulated through the second cooling flow path via a path through the intermediate heat exchanger, the heater, the heater core, and the bypass flow path, thereby heating air via the heater core. During the first operation, the temperature of the refrigerant in the second cooling flow path is difficult to lower. Furthermore, since heat generated by the fuel cell is transferred to the second cooling flow path, the refrigerant in the second cooling flow path can be heated at the intermediate heat exchanger. Consequently, the power required for the heater to heat the refrigerant flowing through the second cooling flow path is reduced.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a fuel cell cooling system. [Background technology]

[0002] The fuel cell system disclosed in Patent Document 1 has a first cooling flow path and a second cooling flow path that circulate a refrigerant. A fuel cell is provided in the first cooling flow path. A radiator is provided in the second cooling flow path. An intermediate heat exchanger is provided across the first and second cooling flow paths. The intermediate heat exchanger exchanges heat between the first and second cooling flow paths. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-33108 Summary of the Invention [Problem to be solved by the invention]

[0004] A fuel cell system may be equipped with a heater that heats a refrigerant and a heater core that uses the heat of the refrigerant to heat the air. The heater core can perform heating operation. This specification proposes a technology for reducing the power consumption of the heater that heats the refrigerant in a fuel cell system capable of heating operation. [Means for solving the problem]

[0005] (Aspect 1) The fuel cell cooling system disclosed in this specification comprises a first cooling flow path that circulates a refrigerant, a fuel cell provided in the first cooling flow path, a second cooling flow path that circulates the refrigerant, a radiator provided in the second cooling flow path, a heater that heats the refrigerant in the second cooling flow path, a heater core that heats air by heat exchange with the refrigerant in the second cooling flow path, and an intermediate heat exchanger that performs heat exchange between the first cooling flow path and the second cooling flow path, wherein the second cooling flow path has a bypass flow path provided in parallel to the radiator, and during power generation by the fuel cell, a first operation is performed in which the refrigerant is circulated in the first cooling flow path through a path passing through the fuel cell and the intermediate heat exchanger, and the refrigerant is circulated in the second cooling flow path through a path passing through the intermediate heat exchanger, the heater, the heater core, and the bypass flow path, thereby heating the air using the heater core.

[0006] In the above fuel cell cooling system, a first operation can be performed while the fuel cell is generating power. In the first operation, the refrigerant circulates through the second cooling flow path via the intermediate heat exchanger, heater, heater core, and bypass flow path. Because the refrigerant circulates through a path that bypasses the radiator, the temperature of the refrigerant in the second cooling flow path is less likely to drop. In addition, heat generated by the fuel cell is transferred to the second cooling flow path via the first cooling flow path and the heat exchanger, allowing the refrigerant in the second cooling flow path to be heated by the intermediate heat exchanger. This reduces the power required by the heater to heat the refrigerant flowing through the second cooling flow path. As a result, the power consumption of the heater can be reduced. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a block diagram of a fuel cell cooling system. [Figure 2] 4 is a flowchart of an operation selection process of the fuel cell cooling system. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] Following the above-mentioned first embodiment, additional configurations of the fuel cell cooling system disclosed in this specification will be described below. (Aspect 2) The second cooling flow path comprises a first circulation system including the bypass flow path, a second circulation system, a first connecting flow path connecting the first circulation system and the second circulation system, and a second connecting flow path connecting the first circulation system and the second circulation system, the intermediate heat exchanger and the radiator are provided in the first circulation system, and the heater and the heater core are provided in the second circulation system, and the first operation and the second operation can be performed, and in the first operation, the intermediate heat exchanger, the first connecting flow path, the heater, the heater core, and the radiator are provided in the second circulation system. and in the second operation, during power generation by the fuel cell, circulates the refrigerant through the first cooling flow path through a path passing through the fuel cell and the intermediate heat exchanger, circulates the refrigerant through the first circulation system through a path passing through the intermediate heat exchanger and the bypass flow path, and circulates the refrigerant through the second circulation system through a path passing through the heater and the heater core, thereby heating air using the heater core. (Aspect 3) A fuel cell cooling system as described in aspect 1 or 2, wherein, during power generation by the fuel cell, a third operation is performed in which a refrigerant is circulated through the first cooling flow path via a path passing through the fuel cell and the intermediate heat exchanger, and a refrigerant is circulated through the second cooling flow path via a path passing through the intermediate heat exchanger, the heater, the heater core, and the radiator, thereby heating air using the heater core. (Aspect 4) A fuel cell cooling system according to any one of aspects 1 to 3, wherein, during power generation by the fuel cell, a fourth operation can be performed, in which a refrigerant is circulated in the first cooling flow path through a path passing through the fuel cell and the intermediate heat exchanger, a refrigerant is circulated in the first circulation system through a path passing through the intermediate heat exchanger and the radiator, and a refrigerant is circulated in the second circulation system through a path passing through the heater and the heater core, thereby heating air using the heater core. (Aspect 5) The fuel cell cooling system according to any one of aspects 1 to 4, wherein the first operation is executed when the temperature of the refrigerant in the first cooling channel is lower than a first reference value and the temperature of the refrigerant in the second cooling channel is higher than a second reference value. (Aspect 6) The fuel cell cooling system according to any one of aspects 1 to 5, wherein the second operation is executed when the temperature of the refrigerant in the first cooling channel is lower than a first reference value and the temperature of the refrigerant in the second cooling channel is lower than a second reference value. (Aspect 7) The fuel cell cooling system according to any one of aspects 1 to 6, wherein the third operation is executed when the temperature of the refrigerant in the first cooling channel is higher than a first reference value and the temperature of the refrigerant in the second cooling channel is higher than a second reference value. (Aspect 8) The fuel cell cooling system according to any one of aspects 1 to 7, wherein the fourth operation is executed when the temperature of the refrigerant in the first cooling channel is higher than a first reference value and the temperature of the refrigerant in the second cooling channel is lower than a second reference value.

[0009] According to the second aspect, the temperature of the fuel cell can be increased, and the second circulation system can perform heating independently.

[0010] According to the third aspect, the radiator cools the coolant, so that the fuel cell can be cooled efficiently.

[0011] According to the fourth aspect, the radiator cools the refrigerant, thereby efficiently cooling the fuel cell. Furthermore, the refrigerant circulates independently in the second circulation system, so the refrigerant cooled by the radiator does not flow into the second circulation system, thereby effectively reducing the power consumption of the heater.

[0012] 1 is mounted on a device powered by a fuel cell (for example, a fuel cell vehicle). The fuel cell cooling system 100 has a first cooling flow path 12, a second cooling flow path 22, and an intermediate heat exchanger 30.

[0013] The intermediate heat exchanger 30 has a first heat exchange passage 30a and a second heat exchange passage 30b. The first heat exchange passage 30a is part of the first cooling passage 12, and the second heat exchange passage 30b is part of the second cooling passage 22. The intermediate heat exchanger 30 causes heat exchange between the first heat exchange passage 30a and the second heat exchange passage 30b. That is, the intermediate heat exchanger 30 causes heat exchange between the first cooling passage 12 and the second cooling passage 22.

[0014] A fuel cell 14 is provided in the first cooling flow path 12. Compressed air is supplied to the fuel cell 14 from an air compressor (not shown), and hydrogen is supplied from a tank (not shown). The fuel cell 14 generates electricity by reacting oxygen and hydrogen, and supplies the electricity to a motor (not shown). The fuel cell 14 is cooled by a refrigerant in the first cooling flow path 12.

[0015] The first cooling flow path 12 is an annular flow path. A pump 16 and temperature sensors 18a and 18b are provided in the first cooling flow path 12. The pump 16 sends out the refrigerant from its installation position toward the intermediate heat exchanger 30. When the pump 16 operates, the refrigerant circulates within the first cooling flow path 12.

[0016] Temperature sensor 18a is provided in first cooling flow path 12, upstream of fuel cell 14. Temperature sensor 18a detects the temperature of the coolant flowing into fuel cell 14. Temperature sensor 18b is provided in first cooling flow path 12, downstream of fuel cell 14. Temperature sensor 18b detects the temperature of the coolant discharged from fuel cell 14 (hereinafter referred to as FC outlet temperature).

[0017] The second cooling flow path 22 has a circulation system 61, a circulation system 62, a first connecting flow path 34a, and a second connecting flow path 34b. The first connecting flow path 34a connects the circulation system 61 and the circulation system 62. The second connecting flow path 34b connects the circulation system 61 and the circulation system 62.

[0018] The circulation system 61 includes flow paths 22a, 22b, and 22c, a bypass flow path 36, a three-way valve 38, and a radiator 24. The flow path 22a is connected to the upstream end of the second heat exchange flow path 30b and the downstream end of the refrigerant flow path in the radiator 24. The flow path 22b is connected to the three-way valve 38 and the downstream end of the second heat exchange flow path 30b. The flow path 22c is connected to the three-way valve 38 and the upstream end of the refrigerant flow path in the radiator 24. The upstream end of the bypass flow path 36 is connected to the three-way valve 38. The downstream end of the bypass flow path 36 is connected to the flow path 22a. The three-way valve 38 switches between a state in which the flow path 22b is connected to the flow path 22c and a state in which the flow path 22b is connected to the bypass flow path 36. The radiator 24 cools the refrigerant flowing through the circulation system 61 by exchanging heat with outside air.

[0019] The circulation system 61 is provided with a pump 26 and temperature sensors 28a, 28b, and 28c. The pump 26 is provided in the flow path 22a, between the intermediate heat exchanger 30 and the bypass flow path 36. The pump 26 sends out the refrigerant from its installation position toward the intermediate heat exchanger 30. When the pump 26 is operated, the refrigerant circulates inside the second cooling flow path 22.

[0020] Temperature sensor 28a is provided in flow path 22a. Temperature sensor 28a detects the temperature of the refrigerant discharged from radiator 24. Temperature sensor 28b is provided in flow path 22c. Temperature sensor 28b detects the temperature of the refrigerant flowing into radiator 24. Temperature sensor 28c is provided in flow path 22b. Temperature sensor 28c detects the temperature of the refrigerant discharged from intermediate heat exchanger 30. In other words, temperature sensor 28c detects the outlet temperature of intermediate heat exchanger 30.

[0021] The circulation system 62 has an air conditioning flow path 50. The air conditioning flow path 50 is a circular flow path. The first connection flow path 34a connects the air conditioning flow path 50 to the flow path 22b of the circulation system 61. The second connection flow path 34b connects the air conditioning flow path 50 to the flow path 22b of the circulation system 61. The connection portion between the first connection flow path 34a and the flow path 22b is located on the upstream side of the connection portion between the second connection flow path 34b and the flow path 22b in the flow path 22b. The air conditioning flow path 50 is provided with a heater 52, a heater core 54, a pump 56, and a three-way valve 58.

[0022] The three-way valve 58 is provided at the connection between the first connection flow path 34a and the air conditioning flow path 50. In other words, the first connection flow path 34a, the upstream portion of the air conditioning flow path 50, and the downstream portion of the air conditioning flow path 50 are connected to the three-way valve 58. The three-way valve 58 switches between a first state in which the refrigerant flows from the first connection flow path 34a to the air conditioning flow path 50, and a second state in which the refrigerant does not flow from the first connection flow path 34a to the air conditioning flow path 50. In the first state, the refrigerant flows from the first connection flow path 34a to the downstream portion of the air conditioning flow path 50 via the three-way valve 58. In the second state, the refrigerant flows from the upstream portion of the air conditioning flow path 50 to the downstream portion of the air conditioning flow path 50 via the three-way valve 58.

[0023] The pump 56 is provided in the air conditioning flow path 50, downstream of the three-way valve 58. The pump 56 sends out the refrigerant from its installation position toward the heater 52.

[0024] The heater 52 is provided in the air conditioning flow path 50, downstream of the pump 56. The heater 52 heats the refrigerant flowing through the air conditioning flow path 50.

[0025] The heater core 54 is provided in the air conditioning flow path 50, downstream of the heater 52. The heater core 54 exchanges heat between the refrigerant in the air conditioning flow path 50 and the outside air, heating the air. The air heated by the heater core 54 is supplied to the vehicle interior, thereby adjusting the temperature inside the vehicle.

[0026] When the fuel cell 14 generates power, the fuel cell 14 generates heat. The control device 40 operates the pumps 16 and 26 while the fuel cell 14 is generating power. When the pump 16 operates, a refrigerant circulates through the first cooling flow path 12. When the pump 26 operates, a refrigerant circulates through the second cooling flow path 22. The fuel cell 14 is cooled by heat exchange between the refrigerant in the first cooling flow path 12 and the fuel cell 14. The heat generated by the power generation of the fuel cell 14 is transferred to the intermediate heat exchanger 30 (i.e., the first heat exchange flow path 30a) by the refrigerant in the first cooling flow path 12. The intermediate heat exchanger 30 transfers the heat from the first heat exchange flow path 30a to the second heat exchange flow path 30b.

[0027] The fuel cell cooling system 100 executes the flowchart shown in FIG.

[0028] In step S2, the control device 40 determines whether the FC outlet temperature is less than the determination temperature T1. If the FC outlet temperature is less than the determination temperature T1 (YES in step S2), the control device 40 controls the three-way valve 38 to open the bypass flow path 36 (step S4). In this case, no refrigerant flows through the radiator 24. If the FC outlet temperature is equal to or higher than the determination temperature T1 (NO in step S2), the control device 40 controls the three-way valve 38 to close the bypass flow path 36 (step S6). In this case, no refrigerant flows through the bypass flow path 36.

[0029] Next, in step S8, the control device 40 determines whether there is a heating request. If there is no heating request (NO in step S8), the control device 40 controls the three-way valve 58 to close the first connection flow path 34a (step S10). In this case, the refrigerant does not flow through the first connection flow path 34a and the second connection flow path 34b. That is, the refrigerant does not flow between the circulation system 61 and the circulation system 62. Also, in step S10, the control device 40 does not operate the pump 56 and the heater 52. Therefore, the heater core 54 does not perform heating.

[0030] When the FC outlet temperature is low (i.e., when the bypass flow path 36 is open), in step S10, the refrigerant pumped out by the pump 26 circulates through the second cooling flow path 22 via a path that passes through the intermediate heat exchanger 30, flow path 22b, and bypass flow path 36. Because the refrigerant in the second cooling flow path 22 is not cooled by the radiator 24, the temperature of the refrigerant flowing into the intermediate heat exchanger 30 is not very low. Therefore, the cooling efficiency of the intermediate heat exchanger 30 when cooling the refrigerant in the first cooling flow path 12 is low. For this reason, the cooling efficiency of the fuel cell 14 is low, and the temperature of the fuel cell 14 gradually increases. In this way, when the FC outlet temperature is low (i.e., when the temperature of the fuel cell 14 is low), the temperature of the fuel cell 14 is increased, thereby increasing the power generation efficiency of the fuel cell 14.

[0031] When the FC outlet temperature is high (i.e., when the bypass flow path 36 is closed), in step S10, the refrigerant pumped out by the pump 26 circulates through the second cooling flow path 22 via a route that passes through the intermediate heat exchanger 30, flow path 22b, flow path 22c, radiator 24, and flow path 22a. Because the refrigerant in the second cooling flow path 22 is cooled by the radiator 24, the temperature of the refrigerant flowing into the intermediate heat exchanger 30 is low. Therefore, the refrigerant in the first cooling flow path 12 is efficiently cooled in the intermediate heat exchanger 30. Therefore, the fuel cell 14 is efficiently cooled by the refrigerant in the first cooling flow path 12. In this way, when the FC outlet temperature is high (i.e., when the temperature of the fuel cell 14 is high), the radiator 24 is operated to efficiently cool the fuel cell 14.

[0032] While there is no heating request, the control device 40 repeatedly executes steps S2 to S10 and S26. Therefore, while there is no heating request, the control device 40 executes the operation of step S10 described above until the vehicle power is turned off (i.e., YES in step S26).

[0033] When there is a heating request (YES in step S8), the control device 40 operates the pump 56. The refrigerant pumped from the pump 56 flows through the heater 52 and the heater core 54 in this order.

[0034] After the pump 56 is operated, the control device 40 determines in step S12 whether the outside air temperature is equal to or lower than the cold temperature determination temperature T2. If the outside air temperature is equal to or lower than the cold temperature determination temperature T2 (YES in step S12), the control device 40 then determines whether the outlet temperature of the intermediate heat exchanger 30 is equal to or lower than the determination temperature T3 (step S14).

[0035] If the outlet temperature of the intermediate heat exchanger 30 is equal to or lower than the determination temperature T3 (YES in step S14), the control device 40 controls the three-way valve 58 to close the first connection flow path 34a (step S16). In this case, the refrigerant does not flow through the first connection flow path 34a and the second connection flow path 34b. In other words, the refrigerant does not flow between the circulation system 61 and the circulation system 62.

[0036] When the FC outlet temperature is low (i.e., when the bypass flow path 36 is open), in step S16, the refrigerant in the second cooling flow path 22 circulates through paths 102 and 104 indicated by the arrows in FIG. 3. In path 102, the refrigerant sent out by the pump 26 circulates through the circulation system 61 via a path that passes through the intermediate heat exchanger 30, flow path 22b, and the bypass flow path 36. Because the refrigerant in the circulation system 61 is not cooled by the radiator 24, the temperature of the refrigerant flowing into the intermediate heat exchanger 30 is not very low. Therefore, the cooling efficiency of the intermediate heat exchanger 30 when cooling the refrigerant in the first cooling flow path 12 is low. For this reason, the cooling efficiency of the fuel cell 14 is low, and the temperature of the fuel cell 14 gradually increases. In this way, when the FC outlet temperature is low, the temperature of the fuel cell 14 is increased, thereby increasing the power generation efficiency of the fuel cell 14.

[0037] In the path 104, the refrigerant pumped by the pump 56 circulates through the circulation system 62 (i.e., the air conditioning flow path 50) via a path that passes through the heater 52 and the heater core 54. The heater 52 heats the refrigerant flowing through the air conditioning flow path 50. The heater core 54 exchanges heat between the refrigerant in the air conditioning flow path 50 and the outside air, heating the air. As a result, the air heated by the heater core 54 is supplied to the vehicle interior, thereby adjusting the temperature inside the vehicle.

[0038] In this way, in step S16 when the FC outlet temperature is low, the refrigerant is circulated independently in the circulation system 61 (i.e., path 102) and the circulation system 62 (i.e., path 104). Therefore, the low-temperature refrigerant in the circulation system 61 does not flow into the circulation system 62, and the heat of the refrigerant heated by the heater 52 can be used to appropriately heat the room with the heater core 54.

[0039] When the FC outlet temperature is high (i.e., when the bypass flow path 36 is closed), in step S16, the refrigerant in the second cooling flow path 22 circulates through paths 106 and 104 indicated by the arrows in FIG. 4. The path 104 shown in FIG. 4 is the same as the path 104 shown in FIG. 3. In path 106, the refrigerant sent out by the pump 26 circulates through the circulation system 61 via the intermediate heat exchanger 30, path 22b, path 22c, radiator 24, and path 22a. Because the refrigerant in the circulation system 61 is cooled by the radiator 24, the temperature of the refrigerant flowing into the intermediate heat exchanger 30 is low. Therefore, the refrigerant in the first cooling flow path 12 is efficiently cooled in the intermediate heat exchanger 30. Therefore, the fuel cell 14 is efficiently cooled by the refrigerant in the first cooling flow path 12. In this way, when the FC outlet temperature is high, the radiator 24 is operated to efficiently cool the fuel cell 14.

[0040] In this way, in step S16 when the FC outlet temperature is high, the refrigerant is circulated independently in the circulation system 61 (i.e., path 106) and the circulation system 62 (i.e., path 104). Therefore, the low-temperature refrigerant in the circulation system 61 does not flow into the circulation system 62, and the heat of the refrigerant heated by the heater 52 can be used to appropriately heat the room with the heater core 54.

[0041] The control device 40 repeatedly executes steps S2 to S8, S12 to S16, and S26 while the outlet temperature of the intermediate heat exchanger 30 is equal to or lower than the determination temperature T3. Therefore, while the outlet temperature of the intermediate heat exchanger 30 is equal to or lower than the determination temperature T3, the control device 40 executes the operation of step S16 described above until the vehicle power is turned off (i.e., YES in step S26).

[0042] If the outlet temperature of the intermediate heat exchanger 30 exceeds the determination temperature T3 (NO in step S14), the control device 40 controls the three-way valve 58 to open the first connection flow path 34a (step S18). In this case, the refrigerant flows through the first connection flow path 34a and the second connection flow path 34b. That is, the refrigerant circulates between the circulation system 61 and the circulation system 62.

[0043] If the FC outlet temperature is low (i.e., if the bypass flow path 36 is open), in step S18, the refrigerant in the second cooling flow path 22 circulates through a path 108 indicated by an arrow in FIG. 5. In the path 108, the refrigerant sent out by the pump 26 circulates through the second cooling flow path 22 via the intermediate heat exchanger 30, the path 22b, the first connecting flow path 34a, the heater 52, the heater core 54, the second connecting flow path 34b, and the bypass flow path 36. Because the refrigerant in the second cooling flow path 22 is not cooled by the radiator 24, the temperature of the refrigerant flowing into the intermediate heat exchanger 30 is not very low. Therefore, the cooling efficiency of the intermediate heat exchanger 30 when cooling the refrigerant in the first cooling flow path 12 is low. For this reason, the cooling efficiency of the fuel cell 14 is low, and the temperature of the fuel cell 14 gradually increases. As the temperature of the fuel cell 14 increases, the power generation efficiency of the fuel cell 14 increases.

[0044] In the intermediate heat exchanger 30, the refrigerant in the second cooling flow path 22 is heated by heat exchange between the first cooling flow path 12 and the second cooling flow path 22. As described above, step S18 is executed when the outlet temperature of the intermediate heat exchanger 30 exceeds the determination temperature T3. Therefore, in step S18, the high-temperature refrigerant that has passed through the intermediate heat exchanger 30 flows into the air conditioning flow path 50. The heater 52 further heats the refrigerant in the air conditioning flow path 50, and the heater core 54 performs heating by utilizing the heat of the refrigerant in the air conditioning flow path 50. Because the temperature of the refrigerant supplied from the intermediate heat exchanger 30 to the air conditioning flow path 50 is high, there is no need for the heater 52 to increase the temperature of the refrigerant that much. For this reason, the heater 52 can be operated at a low output, and the power consumption of the heater 52 is reduced. In this way, when the outlet temperature of the intermediate heat exchanger 30 is high, the heat generated in the fuel cell 14 is supplied to the heater core 54 via the first cooling flow path 12, the intermediate heat exchanger 30, and the second cooling flow path 22, thereby reducing the power consumption of the heater 52.

[0045] If the FC outlet temperature is high (i.e., if the bypass flow path 36 is closed), in step S18, the refrigerant in the second cooling flow path 22 circulates through a path 110 indicated by the arrow in FIG. 6. In the path 110, the refrigerant sent out by the pump 26 circulates through the second cooling flow path 22 via the intermediate heat exchanger 30, the path 22b, the first connecting flow path 34a, the heater 52, the heater core 54, the second connecting flow path 34b, the path 22c, the radiator 24, and the path 22a. Because the refrigerant in the second cooling flow path 22 is cooled by the radiator 24, the temperature of the refrigerant flowing into the intermediate heat exchanger 30 is low. Therefore, the refrigerant in the first cooling flow path 12 is efficiently cooled in the intermediate heat exchanger 30. As a result, the fuel cell 14 is efficiently cooled by the refrigerant in the first cooling flow path 12.

[0046] In the intermediate heat exchanger 30, the refrigerant in the second cooling flow path 22 is heated by heat exchange between the first cooling flow path 12 and the second cooling flow path 22. As described above, step S18 is executed when the outlet temperature of the intermediate heat exchanger 30 exceeds the determination temperature T3. Therefore, in step S18, the high-temperature refrigerant that has passed through the intermediate heat exchanger 30 flows into the air conditioning flow path 50. The heater 52 further heats the refrigerant in the air conditioning flow path 50, and the heater core 54 performs heating by utilizing the heat of the refrigerant in the air conditioning flow path 50. Because the temperature of the refrigerant supplied from the intermediate heat exchanger 30 to the air conditioning flow path 50 is high, there is no need for the heater 52 to increase the temperature of the refrigerant that much. For this reason, the heater 52 can be operated at a low output, and the power consumption of the heater 52 is reduced. In this way, when the outlet temperature of the intermediate heat exchanger 30 is high, the heat generated in the fuel cell 14 is supplied to the heater core 54 via the first cooling flow path 12, the intermediate heat exchanger 30, and the second cooling flow path 22, thereby reducing the power consumption of the heater 52.

[0047] The control device 40 repeatedly executes steps S2 to S8, S12, S14, S18, and S26 while the outlet temperature of the intermediate heat exchanger 30 exceeds the determination temperature T3. Therefore, while the outlet temperature of the intermediate heat exchanger 30 exceeds the determination temperature T3, the control device 40 executes the operation of step S18 described above until the vehicle power is turned off (i.e., YES in step S26).

[0048] If the outside air temperature exceeds the cold determination temperature T2 (NO in step S12), the control device 40 determines whether the outlet temperature of the intermediate heat exchanger 30 is equal to or lower than a determination temperature T4 (step S20). The determination temperature T4 is different from the determination temperature T3 in step S14.

[0049] If the outlet temperature of the intermediate heat exchanger 30 is equal to or lower than the determination temperature T4 (YES in step S20), the control device 40 executes step S22. In step S22, the same operation as in step S16 is executed.

[0050] If the outlet temperature of the intermediate heat exchanger 30 exceeds the determination temperature T4 (NO in step S20), the control device 40 executes step S24. In step S24, the same operation as in step S18 is executed.

[0051] As described above, steps S20 to S24 are the same as steps S14 to S18 except that the determination temperature is different.

[0052] As described above, the control device 40 selectively executes the operations of FIGS. 3 to 6 when there is a heating request.

[0053] When the temperature of the refrigerant in the second cooling flow path 22 is high, the operation of Figure 5 or 6 is performed to circulate the refrigerant in the second cooling flow path 22 through a path spanning circulation systems 61 and 62. This allows the heat generated in the fuel cell 14 to be used by the heater core 54, thereby reducing the power consumption of the heater 52. Furthermore, in this case, when the temperature of the fuel cell 14 is low, the temperature of the fuel cell 14 is increased by the operation of Figure 5 (i.e., an operation in which the radiator 24 does not cool the refrigerant), and when the temperature of the fuel cell 14 is high, the temperature of the fuel cell 14 is decreased by the operation of Figure 6 (i.e., an operation in which the radiator 24 cools the refrigerant). Therefore, it is possible to prevent the temperature of the fuel cell 14 from becoming excessively high while suppressing a decrease in power generation efficiency due to a decrease in the temperature of the fuel cell 14.

[0054] 3 or 4, the refrigerant in the second cooling flow path 22 is circulated through separate paths in the circulation systems 61 and 62. This prevents low-temperature refrigerant from flowing into the air conditioning flow path 50, and prevents an increase in power consumption by the heater 52. In this case, when the temperature of the fuel cell 14 is low, the temperature of the fuel cell 14 is increased by the operation of FIG. 3 (i.e., an operation in which the radiator 24 does not cool the refrigerant), and when the temperature of the fuel cell 14 is high, the temperature of the fuel cell 14 is decreased by the operation of FIG. 4 (i.e., an operation in which the radiator 24 cools the refrigerant). This prevents the temperature of the fuel cell 14 from becoming excessively high, while suppressing a decrease in power generation efficiency due to a decrease in the temperature of the fuel cell 14.

[0055] The operation of executing step S18 in the state where the bypass flow path 36 is open in the embodiment is an example of a first operation. The operation of executing step S16 in the state where the bypass flow path 36 is open in the embodiment is an example of a second operation. The operation of the embodiment is an example of a third operation in which step S18 is executed in the state where the bypass flow path 36 is closed. The operation of the embodiment in which step S16 is executed in the state where the bypass flow path 36 is closed is an example of a fourth operation.

[0056] In the embodiments, the flow path changing device that changes the path through which the refrigerant flows in the second cooling flow path 22 is configured by the three-way valves 38, 58, but the flow path changing device may be configured by other devices. Also, in the embodiments, the three-way valves 38, 58 are solenoid valves, but the flow path changing device may be configured by a device that does not use electricity. For example, the flow path changing device may be configured by a device that switches the flow path by thermal expansion of a material, such as a thermostat.

[0057] In the embodiment, the first to fourth actions are executed by comparing the outlet temperature of the intermediate heat exchanger 30 with the judgment temperatures T3 and T4. However, the first to fourth actions may also be executed by comparing the FC outlet temperature with the judgment temperatures T3 and T4.

[0058] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0059] 12: First cooling channel 14:Fuel cell 22: Second cooling channel 24: Radiator 30: Intermediate heat exchanger 34a: First connecting flow path 34b: Second connecting flow path 36: Bypass flow path 38: Three-way valve 40: Control device 50: Air conditioning flow path 52: Heater 54: Heater core 56: Pump 58: Three-way valve 61 :Circulatory system 62 :Circulatory system 100: Fuel cell cooling system

Claims

1. 1. A fuel cell cooling system, comprising: a first cooling flow path through which a coolant is circulated; a fuel cell provided in the first cooling flow path; a second cooling flow path through which a coolant is circulated; a radiator provided in the second cooling flow path; a heater that heats the refrigerant in the second cooling flow path; a heater core that heats air by heat exchange with the refrigerant in the second cooling flow path; an intermediate heat exchanger that exchanges heat between the first cooling flow path and the second cooling flow path; Equipped with the second cooling flow path includes a bypass flow path provided in parallel with the radiator, During power generation by the fuel cell, a first operation can be performed in which a refrigerant is circulated through the first cooling flow path via a path passing through the fuel cell and the intermediate heat exchanger, and a refrigerant is circulated through the second cooling flow path via a path passing through the intermediate heat exchanger, the heater, the heater core, and the bypass flow path, thereby heating air with the heater core. Fuel cell cooling system.

2. The second cooling channel is a first circulation system including the bypass flow path; A second circulatory system; a first connecting flow path connecting the first circulation system and the second circulation system; a second connecting flow path connecting the first circulation system and the second circulation system; Equipped with the intermediate heat exchanger and the radiator are provided in the first circulation system, the heater and the heater core are provided in the second circulation system, The first operation and the second operation can be performed, In the first operation, a refrigerant is circulated through the second cooling flow path via a path that passes through the intermediate heat exchanger, the first connecting flow path, the heater, the heater core, the second connecting flow path, and the bypass flow path; In the second operation, during power generation by the fuel cell, a refrigerant is circulated in the first cooling flow path through a path passing through the fuel cell and the intermediate heat exchanger, a refrigerant is circulated in the first circulation system through a path passing through the intermediate heat exchanger and the bypass flow path, and a refrigerant is circulated in the second circulation system through a path passing through the heater and the heater core, thereby heating air by the heater core. The fuel cell cooling system of claim 1 .

3. a third operation can be performed in which, during power generation by the fuel cell, a refrigerant is circulated through the first cooling flow path via a path passing through the fuel cell and the intermediate heat exchanger, and a refrigerant is circulated through the second cooling flow path via a path passing through the intermediate heat exchanger, the heater, the heater core, and the radiator, thereby heating air using the heater core.

3. The fuel cell cooling system according to claim 1.

4. During power generation by the fuel cell, a fourth operation can be executed in which a refrigerant is circulated in the first cooling flow path through a path passing through the fuel cell and the intermediate heat exchanger, a refrigerant is circulated in the first circulation system through a path passing through the intermediate heat exchanger and the radiator, and a refrigerant is circulated in the second circulation system through a path passing through the heater and the heater core, thereby heating air by the heater core. The fuel cell cooling system according to claim 2 .

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