Fuel cell cooling system

Abstract

This fuel cell cooling system is provided with a first cooling flow path, a fuel cell, a second cooling flow path, a radiator, an intercooler, an intermediate heat exchanger provided with a first heat exchange flow path and a second heat exchange flow path, a parallel flow path, and a valve, and when the temperature of a refrigerant in the first cooling flow path is lower than a first reference value during power generation by the fuel cell, the parallel flow path is connected to the intercooler, and the temperature of the refrigerant in the second cooling flow path is lower than a second reference value. In the present invention, a first operation is performed in which a refrigerant is circulated in a first cooling flow path in accordance with a path passing through a fuel cell and a first heat exchange flow path, and a refrigerant is circulated in a second cooling flow path in accordance with a path passing through a radiator, a parallel flow path, and an intercooler. When the temperature of the refrigerant in the first cooling flow path is higher than the first reference value, the second operation is performed.

Description

Technical Field

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

[0002] The fuel cell system disclosed in Japanese Patent Application Laid-Open No. 2002-33108 includes a first cooling flow path and a second cooling flow path through which a refrigerant circulates. 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 performs heat exchange between the first and second cooling flow paths.

[0003] In a fuel cell system, an intercooler may be provided to cool the compressed air supplied to the fuel cell. In the technology of Japanese Patent Application Laid-Open No. 2002-33108, if an intercooler is provided in the second cooling flow path, the refrigerant cooled in the radiator can be supplied to the intercooler and the intermediate heat exchanger. The heat generated in the fuel cell during power generation is transferred to the intermediate heat exchanger by the refrigerant flowing in the first cooling flow path. The intermediate heat exchanger cools the refrigerant in the first cooling flow path by heat exchange with the refrigerant in the second cooling flow path (i.e., the refrigerant cooled in the radiator). In addition, the intercooler cools the compressed air by heat exchange with the refrigerant in the second cooling flow path (i.e., the refrigerant cooled in the radiator).

[0004] When the fuel cell is started in a low-temperature environment, the temperature of the fuel cell is low immediately after the start-up, and the power generation efficiency is low. In addition, if the fuel cell is started, refrigerant needs to be supplied to the intercooler. In the above-mentioned fuel cell system, if refrigerant is supplied to the intercooler, refrigerant is also supplied to the intermediate heat exchanger. In this way, the refrigerant in the first cooling flow path is cooled by the intermediate heat exchanger, and the temperature of the fuel cell is difficult to rise. Therefore, the power generation efficiency of the fuel cell is difficult to increase. In this way, if an intercooler is provided in the second cooling flow path, there is a problem that the temperature of the fuel cell is difficult to rise in a low-temperature environment. In this specification, a technology is proposed that can supply refrigerant to the intercooler and can increase the temperature of the fuel cell. Summary of the Invention

[0005] Technical Solution 1

[0006] In the fuel cell cooling system disclosed in this specification, it is provided with: a first cooling flow path for circulating refrigerant; a fuel cell, which is arranged in the above-mentioned first cooling flow path; a second cooling flow path for circulating refrigerant; a radiator, which is arranged in the above-mentioned second cooling flow path; an intercooler, which is arranged in the above-mentioned second cooling flow path; and an intermediate heat exchanger, which has a first heat exchange flow path that constitutes a part of the above-mentioned first cooling flow path, and a second heat exchange flow path that constitutes a part of the above-mentioned second cooling flow path, and heat exchange is performed between the above-mentioned first heat exchange flow path and the above-mentioned second heat exchange flow path, and the above-mentioned second cooling flow path has: a parallel flow path, which is connected in parallel with the above-mentioned intermediate heat exchanger; and a valve, which opens and closes the above-mentioned second heat exchange flow path. During the power generation of the above-mentioned fuel cell, the temperature of the refrigerant in the above-mentioned first cooling flow path is lower than that of the first heat exchange flow path. When the temperature of the refrigerant in the first cooling flow path is higher than the first reference value, the first action is performed. In the first action, the refrigerant is circulated to the first cooling flow path along the path passing through the fuel cell and the first heat exchange flow path, and when the second heat exchange flow path is closed, the refrigerant is circulated in the second cooling flow path along the path passing through the radiator, the parallel flow path and the intercooler. During power generation by the fuel cell, when the temperature of the refrigerant in the first cooling flow path is higher than the first reference value, the second action is performed. In the second action, the refrigerant is circulated in the first cooling flow path along the path passing through the fuel cell and the first heat exchange flow path, and the refrigerant is circulated in the second cooling flow path along the path passing through the radiator, the second heat exchange flow path and the intercooler.

[0007] In this fuel cell cooling system, when the temperature of the refrigerant in the first cooling flow path is lower than a first reference value during power generation by the fuel cell, a first action is performed. In the first action, the refrigerant is circulated in the second cooling flow path along a path passing through the radiator, the parallel flow path, and the intercooler while the second heat exchange flow path is closed. The intercooler can cool the compressed air using the refrigerant circulating in the second cooling flow path. In addition, since the second heat exchange flow path is closed, the refrigerant does not flow into the intermediate heat exchanger. Therefore, heat exchange between the first heat exchange flow path and the second heat exchange flow path is difficult to occur in the intermediate heat exchanger. As a result, the refrigerant in the first cooling flow path is hardly cooled in the intermediate heat exchanger, and the temperature of the fuel cell can be efficiently increased. In this way, according to this fuel cell cooling system, refrigerant can be supplied to the intercooler and the temperature of the fuel cell can be increased.

[0008] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, wherein like reference numerals denote like elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1is a block diagram of the fuel cell cooling system;

[0010] Figure 2 It is an illustration of the path;

[0011] Figure 3 It is an illustration of the path;

[0012] Figure 4 is a flow chart of the action selection process of the fuel cell cooling system;

[0013] Figure 5 This is a flowchart of the operation selection process of the fuel cell cooling system. DETAILED DESCRIPTION

[0014] Following the above-mentioned technical solution 1, the additional structure of the fuel cell cooling system disclosed in this specification will be described below.

[0015] Technical Solution 2

[0016] According to the fuel cell cooling system of claim 1, the intercooler is provided in the parallel flow path, and in the second operation, the refrigerant flows in parallel in the second heat exchange flow path and the parallel flow path.

[0017] Technical Solution 3

[0018] According to the fuel cell cooling system described in technical solution 1 or 2, in the above-mentioned first action, when the temperature of the refrigerant in the above-mentioned first cooling flow path is lower than the second reference value, the circulation speed of the refrigerant in the above-mentioned first cooling flow path is slowed down compared with the case where the temperature of the refrigerant in the above-mentioned first cooling flow path is higher than the above-mentioned second reference value.

[0019] Technical Solution 4

[0020] A fuel cell cooling system according to any one of technical solutions 1 to 3, wherein, in the above-mentioned second action, when the temperature of the refrigerant in the above-mentioned first cooling flow path is higher than the third reference value, the flow rate of the refrigerant in the above-mentioned second heat exchange flow path is made faster than when the temperature of the refrigerant in the above-mentioned first cooling flow path is lower than the above-mentioned third reference value.

[0021] According to the second aspect, the refrigerant cooled in the radiator flows in parallel toward the intercooler and the second heat exchange flow path, so that the intercooler and the intermediate heat exchanger can be operated efficiently.

[0022] According to the third aspect, when the temperature of the coolant in the first cooling flow path is low during the first operation, the temperature of the fuel cell can be increased more quickly.

[0023] According to the fourth aspect, when the temperature of the coolant in the first cooling flow path is high during the second operation, the fuel cell can be cooled more efficiently.

[0024] Figure 1 The fuel cell cooling system 100 shown is mounted on a device using a fuel cell as a power source (eg, a fuel cell electric vehicle). The fuel cell cooling system 100 includes a first cooling flow path 12 , a second cooling flow path 22 , and an intermediate heat exchanger 30 .

[0025] The intermediate heat exchanger 30 includes a first heat exchange flow path 30a and a second heat exchange flow path 30b. The first heat exchange flow path 30a is part of the first cooling flow path 12, and the second heat exchange flow path 30b is part of the second cooling flow path 22. The intermediate heat exchanger 30 exchanges heat between the first heat exchange flow path 30a and the second heat exchange flow path 30b. In other words, the intermediate heat exchanger 30 exchanges heat between the first cooling flow path 12 and the second cooling flow path 22.

[0026] 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 refrigerant in the first cooling flow path 12 cools the fuel cell 14.

[0027] 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 delivers refrigerant from its installation position toward the intermediate heat exchanger 30. When the pump 16 is operated, the refrigerant circulates in the first cooling flow path 12.

[0028] The temperature sensor 18a is provided in the first cooling flow path 12 and upstream of the fuel cell 14. The temperature sensor 18a detects the temperature of the refrigerant flowing into the fuel cell 14 (hereinafter referred to as the FC inlet temperature). The temperature sensor 18b is provided in the first cooling flow path 12 and downstream of the fuel cell 14. The temperature sensor 18b detects the temperature of the refrigerant discharged from the fuel cell 14 (hereinafter referred to as the FC outlet temperature).

[0029] The second cooling flow path 22 is provided with a radiator 24. The radiator 24 cools the refrigerant flowing in the second cooling flow path 22 by exchanging heat with the outside air.

[0030] The second cooling flow path 22 includes a flow path 22a, a flow path 22b, a parallel flow path 34, and a three-way valve 38. The upstream end of the flow path 22a is connected to the downstream end of the refrigerant flow path in the radiator 24. The downstream end of the flow path 22a is connected to the upstream end of the second heat exchange flow path 30b and the upstream end of the parallel flow path 34 via the three-way valve 38. The parallel flow path 34 is arranged in parallel with the second heat exchange flow path 30b. The upstream end of the flow path 22b is connected to the downstream end of the second heat exchange flow path 30b. The downstream end of the flow path 22b is connected to the upstream end of the refrigerant flow path in the radiator 24.

[0031] The three-way valve 38 opens and closes the second heat exchange flow path 30b. The flow rates of the refrigerant flowing into the second heat exchange flow path 30b and the parallel flow path 34 are adjusted according to the opening degree of the three-way valve 38.

[0032] An intercooler 32 is provided in the parallel flow path 34 . The intercooler 32 cools the compressed air supplied to the fuel cell 14 by exchanging heat with the refrigerant flowing in the parallel flow path 34 .

[0033] The fuel cell cooling system 100 includes a pump 26, a temperature sensor 28a, and a temperature sensor 28b. The pump 26 is installed in the flow path 22a. The pump 26 delivers refrigerant from its installation location toward the intermediate heat exchanger 30 and the intercooler 32. When the pump 26 is activated, the refrigerant circulates within the second cooling flow path 22.

[0034] Temperature sensor 28a is provided in flow path 22a. Temperature sensor 28a detects the temperature of the refrigerant discharged from radiator 24 (hereinafter referred to as the radiator outlet temperature). Temperature sensor 28b is provided in flow path 22b. Temperature sensor 28b detects the temperature of the refrigerant flowing into radiator 24 (hereinafter referred to as the radiator inlet temperature).

[0035] The fuel cell cooling system 100 includes a control device 40 . The control device 40 controls the pumps 16 and 26 and the three-way valve 38 based on the temperature of the coolant in the first cooling flow path 12 and the temperature of the coolant in the second cooling flow path 22 .

[0036] 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. While the fuel cell 14 is generating electricity, the fuel cell cooling system 100 can perform warm-up control and normal control as described below.

[0037] Warm-up control is performed when the temperature of the fuel cell 14 is low. During warm-up control, the controller 40 operates the pump 16. When the pump 16 operates, the refrigerant circulates through the first cooling flow path 12, in this order, through the intermediate heat exchanger 30 (i.e., the first heat exchange flow path 30a), and then through the fuel cell 14. Consequently, the refrigerant in the first cooling flow path 12 transfers heat generated by power generation by the fuel cell 14 to the first heat exchange flow path 30a.

[0038] In addition, in the preheating control, the control device 40 operates the pump 26. Furthermore, the control device 40 controls the three-way valve 38 to close the second heat exchange flow path 30b. Figure 2 circulates in the path 101 indicated by the arrow. In the path 101, the refrigerant delivered by the pump 26 circulates in the second cooling flow path 22 along the path passing through the intercooler 32 (i.e., the parallel flow path 34), the flow path 22b, the radiator 24, and the flow path 22a. In this case, the refrigerant does not flow into the second heat exchange flow path 30b. Therefore, in the intermediate heat exchanger 30, the refrigerant in the first heat exchange flow path 30a is hardly cooled. In the intercooler 32, the compressed air supplied to the fuel cell 14 is cooled by heat exchange with the refrigerant flowing in the parallel flow path 34.

[0039] As described above, during warm-up control, the compressed air supplied to the fuel cell 14 is cooled by the intercooler 32, while the refrigerant in the first cooling flow path 12 is hardly cooled by the intermediate heat exchanger 30. Therefore, the temperature of the fuel cell 14 tends to rise.

[0040] Normal control is performed when the temperature of the fuel cell 14 is high. During normal control, the controller 40 operates the pump 16. Consequently, as in warm-up control, refrigerant circulates through the first cooling flow path 12. Consequently, heat generated by power generation by the fuel cell 14 is transferred to the intermediate heat exchanger 30 (i.e., the first heat exchange flow path 30a) via the refrigerant in the first cooling flow path 12.

[0041] In normal control, the control device 40 operates the pump 26. In addition, the control device 40 adjusts the opening of the three-way valve 38 and controls the refrigerant to flow in parallel to the second heat exchange flow path 30b and the parallel flow path 34. Figure 3circulates in the path 102 indicated by the arrow. In the path 102, the refrigerant sent by the pump 26 flows in parallel to the intercooler 32 (i.e., the parallel flow path 34) and the intermediate heat exchanger 30 (i.e., the second heat exchange flow path 30b). The refrigerant that has passed through the intermediate heat exchanger 30 and the intercooler 32 then flows to the radiator 24. The radiator 24 cools the refrigerant in the second cooling flow path 22 by heat exchange with the outside air. Therefore, the refrigerant cooled in the radiator 24 flows to the intermediate heat exchanger 30 and the intercooler 32. The intermediate heat exchanger 30 cools the refrigerant in the first cooling flow path 12 by heat exchange between the first cooling flow path 12 and the second cooling flow path 22. Since the refrigerant in the second cooling flow path 22 is cooled in the radiator 24, the intermediate heat exchanger 30 can efficiently cool the refrigerant in the first cooling flow path 12. Furthermore, the intercooler 32 cools the compressed air supplied to the fuel cell 14 by exchanging heat with the refrigerant flowing in the parallel flow path 34 .

[0042] As described above, in normal control, the compressed air supplied to the fuel cell 14 can be cooled by the intercooler 32 , and the refrigerant in the first cooling flow path 12 can be efficiently cooled in the intermediate heat exchanger 30 .

[0043] Figure 4 The processing executed by the control device 40 during the operation of the fuel cell 14 is shown in more detail.

[0044] In S2, the control device 40 measures the outside air temperature using a temperature sensor (not shown). The control device 40 determines whether the outside air temperature is below the cold determination temperature T1. When the vehicle is parked, the refrigerant temperature is roughly the same as the outside air temperature. Therefore, the process in S2 is equivalent to determining whether the temperature of the refrigerant flowing through the first cooling flow path 12 is below the cold determination temperature T1.

[0045] If the outside air temperature is below the cold determination temperature T1 (if YES in S2), the controller 40 performs cold warm-up control in S4. During cold warm-up control, the controller 40 performs the warm-up control described above. During cold warm-up control, the controller 40 controls the discharge flow rate of the pump 26 based on the radiator outlet temperature and the heat capacity of the compressed air flowing into the intercooler 32. Furthermore, during cold warm-up control, the controller 40 controls the output current of the fuel cell 14 and the discharge flow rate of the pump 16 based on the FC inlet temperature. In this case, the discharge flow rate of the pump 16 is controlled to a low value. As described above, the temperature of the fuel cell 14 tends to rise during warm-up control. In particular, during cold warm-up control, the discharge flow rate of the pump 16 is low, making it difficult for heat to transfer from the fuel cell 14 to the refrigerant. Consequently, the temperature of the fuel cell 14 tends to rise. Thus, by implementing cold warm-up control when the air temperature is below the cold determination temperature T1, the temperature of the fuel cell 14 rises rapidly. This improves the power generation efficiency of the fuel cell 14.

[0046] If the FC outlet temperature is lower than the cold warm-up control end temperature T2, the control device 40 performs the cold warm-up control until the vehicle power is turned off (i.e., YES in S6 and NO in S8). If the FC outlet temperature exceeds the cold warm-up control end temperature T2 (NO in S6), the control device 40 performs S12.

[0047] If the outside air temperature is higher than the cold determination temperature T1 in S2 (if NO in S2), the control device 40 determines in S10 whether the FC outlet temperature is lower than the preheating control end temperature T3. Specifically, the control device 40 determines whether the temperature of the refrigerant flowing through the first cooling flow path 12 is lower than the preheating control end temperature T3. The preheating control end temperature T3 is higher than both the cold determination temperature T1 and the cold preheating control end temperature T2.

[0048] If the FC outlet temperature is lower than the warm-up control end temperature T3 (if YES in S10), the controller 40 performs normal warm-up control in S12. During normal warm-up control, the controller 40 performs the warm-up control described above. During normal warm-up control, the controller 40 controls the discharge flow rate of the pump 26 based on the radiator outlet temperature and the heat capacity of the compressed air flowing into the intercooler 32. During normal warm-up control, the controller 40 controls the output current of the fuel cell 14 and the discharge flow rate of the pump 16 based on the FC inlet temperature. During normal warm-up control, the discharge flow rate of the pump 16 is controlled to a higher value (i.e., a value higher than that in S4). As described above, the temperature of the fuel cell 14 tends to rise during warm-up control. However, the higher discharge flow rate of the pump 16 during normal warm-up control makes the temperature of the fuel cell 14 less likely to rise than during cold warm-up control. Thus, when the temperature of the fuel cell 14 is somewhat high, the power generation of the fuel cell 14 is reduced compared to cold warm-up control, while the refrigerant flow rate is increased, thereby mitigating the temperature gradient within the fuel cell 14.

[0049] If the FC outlet temperature is lower than the warm-up control end temperature T3, the control device 40 performs normal warm-up control until the vehicle power is turned off (i.e., YES in S10 and NO in S14). If the FC outlet temperature exceeds the warm-up control end temperature T3 (NO in S10), the control device 40 performs S16.

[0050] In S16, the control device 40 performs the above-described normal control. At this time, the opening of the three-way valve 38 remains fixed. Thus, when the FC outlet temperature is high (i.e., when the temperature of the fuel cell 14 is high), the normal control effectively cools the fuel cell 14. This prevents excessive temperature increases in the fuel cell 14.

[0051] If the FC outlet temperature is higher than the warm-up control restart temperature T4, the control device 40 performs normal control until the vehicle power is turned off (i.e., NO in S18 and NO in S20). Furthermore, the warm-up control restart temperature T4 is lower than the warm-up control end temperature T3. If the FC outlet temperature is lower than the warm-up control restart temperature T4 (YES in S18), the control device 40 performs normal warm-up control in S12.

[0052] In the above embodiment, the opening of the three-way valve 38 is fixed in S16. However, the opening of the three-way valve 38 may be adjusted based on the calorific value of the fuel cell 14, the FC outlet temperature, and the heat capacity of the compressed air flowing into the intercooler 32. In this case, the control device 40 executes the following operation during the execution of S16 (i.e., during the execution of normal control): Figure 5processing (i.e., S22 to S30).

[0053] In S22, the control device 40 determines the output of the fan of the radiator 24 based on the amount of heat generated by the fuel cell 14 and the vehicle speed. As a result, the refrigerant in the radiator 24 is appropriately cooled.

[0054] Next, in S24, the control device 40 determines the amount Q1 (hereinafter referred to as flow rate Q1) of refrigerant flowing into the intercooler 32 based on the heat capacity of the compressed air flowing into the intercooler 32 and the radiator outlet temperature. Furthermore, the control device 40 determines the amount Q2 (hereinafter referred to as flow rate Q2) of refrigerant flowing into the intermediate heat exchanger 30 based on the heating value of the fuel cell 14.

[0055] Next, the control device 40 determines in S26 whether the FC outlet temperature is lower than the target temperature T5. Specifically, the control device 40 determines whether the temperature of the refrigerant flowing through the first cooling flow path 12 is lower than the target temperature T5. If the FC outlet temperature is lower than the target temperature T5 (if the answer is yes in S26), the control device 40 proceeds to S28.

[0056] In S28, the control device 40 adjusts the opening of the three-way valve 38 and the output of the pump 26 based on the values ​​of the flow rates Q1 and Q2 (i.e., flow rates) determined in S24. Since the flow rate Q2 is determined based on the heat generation of the fuel cell 14, heat exchange can be efficiently performed between the refrigerant flowing through the intermediate heat exchanger 30 and the refrigerant flowing through the first cooling flow path 12. Therefore, the fuel cell 14 is efficiently cooled. In addition, the flow rate Q1 is determined based on the heat capacity of the compressed air flowing into the intercooler 32 and the radiator outlet temperature. As a result, the compressed air supplied to the fuel cell 14 is cooled more efficiently in the intercooler 32.

[0057] When the FC outlet temperature exceeds the target temperature T5 (NO in S26), the control device 40 performs S30.

[0058] In S30 , the control device 40 determines the value of the flow rate Q3 (ie, flow velocity) of the refrigerant flowing into the intermediate heat exchanger 30 so as to satisfy the following relational expression.

[0059] Q3=Q2·{1+a·(FC outlet temperature-T5)}

[0060] The value of the flow rate Q3 is larger than the flow rate Q2.

[0061] Next, S30 adjusts the opening of the three-way valve 38 and the output of the pump 26 based on the determined flow rates Q1 and Q3. Since flow rate Q3 is greater than flow rate Q2, heat exchange between the refrigerant flowing through the intermediate heat exchanger 30 and the refrigerant flowing through the first cooling flow path 12 is facilitated in S30 compared to S28. Consequently, the fuel cell 14 can be cooled more efficiently.

[0062] In the above embodiment, the three-way valve 38 is provided at the connection portion with the flow path 22a, the parallel flow path 34, and the upstream end of the second heat exchange flow path 30b. However, the three-way valve 38 may also be provided at the connection portion with the flow path 22b, the parallel flow path 34, and the downstream end of the second heat exchange flow path 30b.

[0063] In the above embodiment, the three-way valve 38 constitutes the flow path changing device that changes the refrigerant flow path within the second cooling flow path 22. However, the flow path changing device may also be constituted by another device. Furthermore, in the embodiment, the three-way valve 38 is a solenoid valve, but the flow path changing device may also be constituted by a device that does not use electricity. For example, the flow path changing device may also be constituted by a device that switches the flow path based on the thermal expansion of a material, such as a thermostat.

[0064] In the embodiment, the intercooler 32 is provided in the parallel flow path 34. However, the intercooler 32 may also be provided in the flow path 22a. Furthermore, the intercooler 32 may also be provided in the flow path 22b and between the parallel flow path 34 and the radiator 24. In other words, the refrigerant may flow in series through the intermediate heat exchanger 30 and the intercooler 32.

[0065] In S4 and S12 of the above embodiment, the control device 40 controls the discharge flow rate of the pump 16 according to the FC inlet temperature. However, in S4 and S12, the discharge flow rate of the pump 16 may be controlled by a map relationship.

[0066] In S4 and S12 of the above embodiment, the discharge flow rate of the pump 26 is controlled based on the radiator outlet temperature and the heat capacity of the compressed air flowing into the intercooler 32. However, in S4 and S12, the discharge flow rate of the pump 26 may be controlled by mapping.

[0067] In the above embodiment, the fan output of the radiator 24 is determined based on the heat output of the fuel cell 14 and the vehicle speed. However, the amount of heat dissipated by the radiator 24 may be calculated based on the radiator outlet temperature and the radiator inlet temperature, and the fan output of the radiator 24 may be determined based on a comparison between the heat output of the fuel cell 14 and the heat dissipated by the radiator 24.

[0068] The cold preheating control and the normal preheating control of the embodiment are examples of the first operation. In addition, the normal control is an example of the second operation.

[0069] The warm-up control end temperature T3 of the embodiment is an example of the first reference value. The cold determination temperature T1 of the embodiment is an example of the second reference value. The target temperature T5 is an example of the third reference value.

[0070] While 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 encompasses various variations and modifications of the specific examples exemplified above. The technical elements described in this specification or the accompanying drawings may exhibit technical utility individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies exemplified in this specification or the accompanying drawings can achieve multiple objectives simultaneously, and achieving one of these objectives alone may be technically useful.

Claims

1. A fuel cell cooling system, wherein: The fuel cell cooling system comprises: A first cooling flow path for circulating the refrigerant; A fuel cell is provided in the first cooling flow path; A second cooling flow path for circulating the refrigerant; a radiator, disposed in the second cooling flow path; an intercooler, disposed in the second cooling flow path; as well as an intermediate heat exchanger including a first heat exchange channel constituting a portion of the first cooling channel and a second heat exchange channel constituting a portion of the second cooling channel, and performing heat exchange between the first heat exchange channel and the second heat exchange channel. The second cooling flow path includes: a parallel flow path connected in parallel with respect to the intermediate heat exchanger; and A valve is used to open and close the second heat exchange flow path. During power generation by the fuel cell, when the temperature of the refrigerant in the first cooling flow path is lower than a first reference value, a first action is performed. In the first action, the refrigerant is circulated in the first cooling flow path along a path passing through the fuel cell and the first heat exchange flow path, and with the second heat exchange flow path closed, the refrigerant is circulated in the second cooling flow path along a path passing through the radiator, the parallel flow path, and the intercooler. During power generation by the fuel cell, when the temperature of the refrigerant in the first cooling flow path is higher than the first reference value, a second action is performed. In the second action, the refrigerant is circulated in the first cooling flow path along a path passing through the fuel cell and the first heat exchange flow path, and the refrigerant is circulated in the second cooling flow path along a path passing through the radiator, the second heat exchange flow path, and the intercooler.

2. The fuel cell cooling system according to claim 1, wherein: The intercooler is arranged in the parallel flow path, In the second operation, the refrigerant flows in parallel in the second heat exchange flow path and the parallel flow path.

3. The fuel cell cooling system according to claim 1 or 2, wherein: In the first action, when the temperature of the refrigerant in the first cooling flow path is lower than a second reference value, the circulation speed of the refrigerant in the first cooling flow path is slowed compared to when the temperature of the refrigerant in the first cooling flow path is higher than the second reference value.

4. The fuel cell cooling system according to claim 1 or 2, wherein: In the second action, when the temperature of the refrigerant in the first cooling flow path is higher than a third reference value, the flow rate of the refrigerant in the second heat exchange flow path is increased compared to when the temperature of the refrigerant in the first cooling flow path is lower than the third reference value.

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