JP2021190168A - Fuel cell cooling system - Google Patents

Abstract

To provide a fuel cell cooling system capable of exhausting air in a case where air is mixed into a coolant passage connected from an upper side in a gravity direction to a confluent part.SOLUTION: A fuel cell cooling system 1000 comprises at least: a radiator passage 104 in which a liquid-state coolant for cooling a fuel cell 120 flows; an ion exchanger passage 106 which is branched from the radiator passage 104 in a branch part and confluent with the radiator passage 104 in a confluent part 107; a three-way valve 160 which controls flow rates of the coolant to flow to the radiator passage 104 and the ion exchanger passage 106; a control unit 300 which controls an opening degree of the three-way valve 160; and a detection unit 400 capable of detecting that a gas is mixed into the coolant. The radiator passage 104 is a passage connected from an upper side in a gravity direction to the confluent part 107. In a case where it is detected by the detection unit 400 that a gas is mixed into the coolant, the control unit 300 controls the opening degree of the three-way valve 160 in such a manner that the flow rate of the coolant to flow into the radiator passage 104 becomes more than the flow rate of the coolant to flow into the ion exchanger passage 106.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fuel cell cooling system.

Conventionally, in a fuel cell system equipped with an ion exchanger that removes ions contained in the refrigerant and a three-way valve that adjusts the flow rate of the refrigerant flowing through the ion exchanger, the refrigerant that flows through the ion exchanger at the start of use of the fuel cell system. It is known that the three-way valve is controlled so that the flow rate of the three-way valve is higher than the flow rate of the refrigerant subsequently flowing into the ion exchanger (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-31108

The ion exchanger contains an ion exchange resin for adsorbing and removing ions in the refrigerant. Since there is a certain limit to the amount of ions that can be adsorbed by the ion exchange resin, it is desirable that the ion exchange resin be replaced regularly during maintenance. On the other hand, when replacing the ion exchange resin, air may be mixed into the refrigerant.

In addition to replacing the ion exchange resin, air may be mixed into the refrigerant when, for example, parts related to the cooling circuit are removed, replaced, or repaired at the time of maintenance. Further, even when the refrigerant itself is replaced, air may be mixed into the refrigerant.

When air is mixed in the refrigerant, in the refrigerant circuit through which the refrigerant flows, one flow path and another flow path merge at the confluence, and the other flow paths are connected to the confluence from above in the direction of gravity. If it is configured as such, there is a possibility that air may enter the other flow path from the confluence portion due to buoyancy. In this case, there is a problem that the cooling efficiency of the fuel cell is lowered unless the air that has entered the other flow path is discharged.

In view of the above problems, an object of the present disclosure is to provide a fuel cell cooling system capable of discharging air when air is mixed in a flow path of a refrigerant connected to a confluence from above in the direction of gravity. To do.

The gist of this disclosure is as follows.

(1) A first flow path through which a liquid refrigerant for cooling the fuel cell flows, and a second flow path that branches from the first flow path at the branch portion and merges with the first flow path at the confluence portion. , A valve device that controls the flow rate of the refrigerant flowing in each of the first flow path and the second flow path, a control unit that controls the opening degree of the valve device, and detection that can detect that gas is mixed in the refrigerant. A fuel cell cooling system including at least a unit, the first flow path is a flow path connected to the confluence from the upper side in the direction of gravity, and the control unit is a flow path in which gas is sent to the refrigerant by the detection unit. Cooling of the fuel cell that controls the opening of the valve device so that the flow rate of the refrigerant flowing into the first flow path becomes larger than the flow rate of the refrigerant flowing into the second flow path when it is detected that the mixture is detected. system.

According to the present disclosure, there is provided a fuel cell cooling system capable of discharging air when air is mixed in a flow path of a refrigerant connected to a confluence portion from above in the direction of gravity.

It is a figure which shows the structure of the cooling system of a fuel cell which concerns on one Embodiment of this invention. It is a schematic diagram which shows the flow of the refrigerant when a three-way valve is set on the flow path side of an ion exchanger, and a water pump is driven. It is a schematic diagram which shows the flow of the refrigerant when the three-way valve is set on the radiator flow path side, and the water pump is driven. It is a flowchart which shows the process performed at the time of maintenance of a cooling system. It is a figure which shows the structure of the cooling system which concerns on the modification.

FIG. 1 is a diagram showing a configuration of a cooling system 1000 of a fuel cell 120 according to an embodiment of the present invention. In this embodiment, as an example, the cooling system 1000 of the fuel cell 120 applied to the fuel cell vehicle will be described. The fuel cell vehicle drives the motor by the electricity generated by the fuel cell 120 and runs by the driving force of the motor. However, the cooling system 1000 is not limited to the fuel cell vehicle application, and can be applied to other applications.

The fuel cell 120 is, for example, a solid polymer electrolyte fuel cell, and includes a cell stack in which a large number of single cells are stacked. Here, the single cell has a membrane / electrode assembly (MEA) in which a polyelectrolyte film is sandwiched between an anode electrode and a cathode electrode, and a pair of separators that sandwich the MEA from both sides. .. The fuel cell 120 generates electricity by a redox reaction between oxygen gas in the air supplied via the separator on the cathode side and hydrogen gas supplied via the separator on the anode side.

Specifically, the oxidation reaction of the formula (1) occurs at the anode electrode, and the reduction reaction of the formula (2) occurs at the cathode electrode. Then, the chemical reaction of the formula (3) occurs in the fuel cell 120 as a whole.
_{^{H 2 → 2H + + 2e -}} ··· (1)
(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O ・ ・ ・ (2)
H ₂ + (1/2) O ₂ → H ₂ O ・ ・ ・ (3)

In FIG. 1, the cooling system 1000 has a cooling circuit 100 through which a liquid refrigerant (for example, cooling water) for cooling the fuel cell 120 flows. The cooling circuit 100 is divided into a basic flow path 102, a radiator flow path (first flow path) 104, an ion exchanger flow path (second flow path) 106, and an intercooler flow path 108.

The water pump 110 and the fuel cell 120 are provided in this order in the basic flow path 102 in the direction of circulation of the refrigerant. The radiator 130 is provided in the radiator flow path 104. Further, the ion exchanger 140 is provided in the ion exchanger flow path 106. Further, the intercooler 150 is provided in the intercooler flow path 108.

The basic flow path 102 is a flow path from the confluence 107 of the radiator flow path 104 and the ion exchanger flow path 106 to the three-way valve 160 described later via the fuel cell 120. The radiator flow path 104 is a flow path from the three-way valve 160 to the confluence portion 107 via the radiator 130. The ion exchanger flow path 106 is a flow path from the three-way valve 160 to the merging portion 107 via the ion exchanger 140. The intercooler flow path 108 is a flow path in which the refrigerant flowing through the basic flow path 102 bypasses the fuel cell 120 and flows into the intercooler 150. The radiator flow path 104, the ion exchanger flow path 106, and the intercooler flow path 108 are provided in parallel with each other and are connected to the basic flow path 102, respectively.

The water pump 110 provided in the basic flow path 102 pumps the refrigerant circulating in the cooling circuit 100 and supplies the refrigerant to the fuel cell 120. The fuel cell 120 is cooled, and the refrigerant flowing out of the fuel cell 120 is supplied to the radiator 130 provided in the radiator flow path 104 or the ion exchanger 140 provided in the ion exchanger flow path 106.

The radiator 130 provided in the radiator flow path 104 is a heat exchanger that exchanges heat between the refrigerant circulating in the cooling circuit 100 and the outside air. Therefore, the radiator 130 is exposed to the traveling wind generated when the fuel cell vehicle travels. Further, the radiator 130 is exposed to the outside air blown by the blower fan 132.

The ion exchanger 140 provided in the ion exchanger flow path 106 has a function of removing ions in the refrigerant. Ions are eluted from the fuel cell 120, the piping of each flow path, and the like in the refrigerant, and when the refrigerant contains a large amount of ions, the conductivity of the refrigerant increases. Since the electricity generated by each single cell of the fuel cell 120 is taken out through the separator, electricity is flowing through the separator, and the potentials of the adjacent separators are different from each other. If the refrigerant passing between the adjacent separators of the fuel cell 120 contains a large amount of ions, a current may flow between the separators to cause a short circuit. Therefore, by removing the ions in the refrigerant by the ion exchanger 140, it is configured to suppress the increase in the conductivity of the refrigerant.

A part of the refrigerant flowing out from the fuel cell 120 circulates in the air conditioning heat linkage circuit 200. The air-conditioning heat linkage circuit 200 has a heater core, and heats the inside of the vehicle by exchanging heat between the circulating refrigerant and the air around the heater core. Specifically, the heater core is configured to exhaust heat from the refrigerant to the air around the heater core. Therefore, when a high-temperature refrigerant flows through the heater core, the temperature of the refrigerant drops and the air around the heater core is warmed.

A three-way valve 160 is provided between the basic flow path 102, the radiator flow path 104, and the ion exchanger flow path 106. The three-way valve 160 is a valve device provided at a branch portion where the radiator flow path 104 and the ion exchanger flow path 106 branch, and adjusts the flow rate of the refrigerant flowing in each of the radiator flow path 104 and the ion exchanger flow path 106. .. The valve device is not limited to the three-way valve 160, and the radiator flow path 104 and the ion exchanger flow path 106 are located downstream of the branch where the radiator flow path 104 and the ion exchanger flow path 106 branch, respectively. It may be composed of two valves provided in the.

Specifically, the three-way valve 160 controls the flow mode of the refrigerant flowing out from the fuel cell 120, and can selectively change the distribution destination between the radiator flow path 104 and the ion exchanger flow path 106. It is configured as follows. When the three-way valve 160 is set on the radiator flow path 104 side, the refrigerant flowing out of the fuel cell 120 flows through the radiator flow path 104. On the other hand, when the three-way valve 160 is set on the ion exchanger flow path 106 side, the refrigerant flowing out of the fuel cell 120 flows through the ion exchanger flow path 106.

The intercooler 150 is a heat exchanger that exchanges heat between the refrigerant circulating in the cooling circuit 100 and the air (cathode gas) supplied to the cathode electrode side of the fuel cell 120. When the cathode gas is supplied to the cathode electrode, it is compressed by the compressor and the temperature rises. The cathode gas whose temperature has risen is cooled by exchanging heat with the refrigerant in the intercooler 150.

In FIG. 1, a three-way valve for controlling the flow rate of the refrigerant flowing to the intercooler flow path 108 may be provided at the branch portion between the basic flow path 102 and the intercooler flow path 108. Similarly, a three-way valve for controlling the flow rate of the refrigerant flowing to the air conditioning heat linkage circuit 200 may be provided at the branch portion between the basic flow path 102 and the flow path toward the air conditioning heat linkage circuit 200.

Referring to FIG. 1, the cooling system 1000 includes a reserve tank 170. Refrigerant is stored in the reserve tank 170. The reserve tank 170 is connected to the cooling circuit 100 via three flow paths 172, 174, 176. When air (gas) is mixed in the refrigerant, when the refrigerant circulates in the cooling circuit 100, the mixed air gradually flows from the portion where the cooling circuit 100 and the flow paths 172, 174, 176 are connected to the flow path 1722. It enters 174,176, exits the reserve tank 170, and is gradually released into the atmosphere.

In the basic flow path 102, a temperature sensor 180 for detecting the temperature of the refrigerant flowing out of the fuel cell 120 is provided downstream of the fuel cell 120. Further, in the radiator flow path 104, a temperature sensor 182 for detecting the temperature of the refrigerant flowing out of the radiator 130 is provided downstream of the radiator 130.

Referring to FIG. 1, the cooling system 1000 includes an electronic control unit (ECU) 300. The ECU 300 includes a processor that performs various calculations, a memory that stores programs and various information, and an interface that is connected to various actuators and various sensors.

Further, the cooling system 1000 includes an air mixing detection unit 400 capable of detecting that air has been mixed in the refrigerant. The air mixing detection unit 400 is composed of, for example, an operation panel provided in a fuel cell vehicle. As will be described later, when the cooling circuit 100 is maintained, air may be mixed in the refrigerant, so an air bleeding process for removing the mixed air is performed. At that time, the air bleeding process is started triggered by the operator operating the operation panel to set the air bleeding mode. Therefore, when the air mixing detection unit 400 is composed of an operation panel, the air mixing detection unit 400 detects that air has been mixed into the refrigerant by detecting the air bleeding trigger when the air bleeding mode is set. It can be detected. The air mixing detection unit 400 may be a sensor that actually detects the mixing of air into the cooling circuit 100.

In FIG. 1, the water pump 110 and the three-way valve 160 are each driven by an actuator. The ECU 300 electrically controls each actuator by executing a control program stored in the memory by the processor based on the operation information obtained from the operation panel and the sensor signals from various sensors.

In the cooling circuit 100, the change of the distribution destination by the three-way valve 160 is performed with priority given to the cooling of the fuel cell 120. For example, when the outside air temperature is high, or when the fuel cell vehicle is operated with a high load, the temperature of the fuel cell 120 tends to rise. Under such conditions, the three-way valve 160 is set on the radiator flow path 104 side, and the refrigerant flowing out of the fuel cell 120 is supplied to the radiator 130. As a result, heat exchange is performed between the refrigerant and the outside air in the radiator 130, and the low-temperature refrigerant is supplied to the fuel cell 120, so that the fuel cell 120 is cooled. On the other hand, for example, when the outside air temperature is low, or when the fuel cell vehicle is operated with a low load, the temperature of the fuel cell 120 is relatively low. Under such conditions, the three-way valve 160 is set on the ion exchanger flow path 106 side. The ECU 300 controls the three-way valve 160 and the water pump 110 based on the refrigerant temperature, the outside air temperature, the load of the fuel cell vehicle, etc. detected by the temperature sensors 180 and 182 so that the fuel cell 120 becomes the optimum temperature. Control.

On the other hand, the change of the distribution destination by the three-way valve 160 may be performed based on the amount of ions contained in the refrigerant. The electrical resistance of the refrigerant is constantly measured by an earth leakage detector (not shown), and when the electrical resistance falls below a predetermined threshold, it is determined that there are many ions contained in the refrigerant, and the three-way valve 160 is the ion exchanger flow path 106. Set to the side. As a result, the refrigerant flowing out of the fuel cell 120 is supplied to the ion exchanger 140, and the ions contained in the refrigerant are removed. For example, when starting a fuel cell vehicle, the refrigerant may contain a large amount of ions eluted while the vehicle is stopped. Therefore, the three-way valve 160 is set on the ion exchanger flow path 106 side and is contained in the refrigerant by the ion exchanger 140. Ions are removed.

Next, in the cooling system 1000 according to the present embodiment configured as described above, when air is mixed in the refrigerant of the cooling circuit 100, the control performed to remove the mixed air will be described. One of the factors that cause air to enter the refrigerant is the case where the cooling circuit 100 is maintained. Specifically, air may be mixed with the refrigerant when the parts related to the cooling circuit 100 are removed, replaced or repaired at the time of maintenance. Further, even when the refrigerant itself is replaced, air may be mixed into the refrigerant.

In the present embodiment, as an example, a case where the ion exchanger 140 is maintained will be described as an example. The ion exchanger 140 contains an ion exchange resin for adsorbing and removing ions in the refrigerant. Since there is a certain limit to the amount of ions that can be adsorbed by the ion exchange resin, the ion exchange resin is regularly replaced during maintenance such as vehicle inspection. When exchanging the ion exchange resin, the old ion exchange resin is removed from the ion exchanger 140, and the new ion exchange resin is attached to the ion exchange 140.

The ion exchange resin is composed of a porous resin, and the new ion exchange resin is mounted on the ion exchanger 140 with air in the porous pores. Therefore, when the refrigerant is circulated in the cooling circuit 100 after the ion exchange resin is replaced, air is mixed in the refrigerant.

When air is mixed in the refrigerant, the cooling efficiency of the fuel cell 120 is lowered, so that the air bleeding process is performed immediately after the ion exchange resin is replaced. In the air bleeding process, the three-way valve 160 is set on the ion exchanger flow path 106 side, and the water pump 110 is driven. FIG. 2 is a schematic view showing the flow of the refrigerant when the three-way valve 160 is set on the ion exchanger flow path 106 side and the water pump 110 is driven. As shown in FIG. 2, by setting the three-way valve 160 on the ion exchanger flow path 106 side, the refrigerant flows in the cooling circuit 100 in the direction indicated by the arrow A1 in FIG. The mixed air is gradually sent to the reserve tank 170 via the flow paths 172 and 174 in the process in which the refrigerant circulates in the basic flow path 102 and the ion exchanger flow path 106 along the arrow A1, and is gradually sent from the reserve tank 170. It is released gradually. By performing this air bleeding process for a predetermined time, the air contained in the ion exchange resin is removed from the cooling circuit 100.

On the other hand, in the process of bleeding air, the air contained in the ion exchange resin travels from the confluence 107 between the radiator flow path 104 and the ion exchange flow path 106 in the direction of arrow A2 shown in FIG. 2, and the radiator flow path. The 104 may flow backward.

In particular, as shown in FIG. 1, when the pipe of the radiator flow path 104 extends upward from the confluence 107 in the direction of gravity, the air discharged from the ion exchange resin flows through the radiator flow path 104 due to buoyancy. It flows backward and does not follow the flow of the refrigerant flowing in the direction of arrow A1 in FIG. In the state of FIG. 2, since the refrigerant does not flow in the radiator flow path 104, the air flowing back in the radiator flow path 104 does not flow in the direction of arrow A1 and is not discharged from the reserve tank 170 and is not discharged from the radiator flow path 104. Stay within 130. Then, the air staying in the radiator flow path 104 stays in the radiator flow path 104 or the radiator 130 until the fuel cell vehicle is operated after the maintenance and the refrigerant flows in the radiator flow path 104.

When the fuel cell vehicle is operated after maintenance and the refrigerant flows in the radiator flow path 104 in the scene of cooling the fuel cell 120, the air remaining in the radiator flow path 104 or the radiator 130 circulates in the cooling circuit 100 and flows. It is gradually discharged from the reserve tank 170 via the roads 172, 174, and 176. However, since it takes a certain amount of time for the air to be completely discharged from the cooling circuit 100, the cooling efficiency of the fuel cell 120 due to the air mixed in the cooling circuit 100 until the air is completely discharged. Decreases.

As described above, when air is mixed in the flow path through which the refrigerant passes, if the flow path is provided with a merging portion and there is a flow path connected to the merging portion from above in the direction of gravity, the air Receives buoyancy and enters the flow path connected from above in the direction of gravity. At this time, if there is no flow in the flow path connected from the upper side in the direction of gravity, air is not discharged, so that the cooling efficiency of the entire system is lowered.

Therefore, in the present embodiment, the flow rate of the refrigerant flowing into the radiator flow path 104 after the air bleeding process is performed by flowing the refrigerant in the direction indicated by the arrow A1 in FIG. 2 is the flow rate of the refrigerant flowing into the ion exchanger flow path 106. The opening degree of the three-way valve 160 is controlled so as to be larger than the above. As a result, the air flowing back through the radiator flow path 104 is expelled from the radiator flow path 104, so that the state in which the air is mixed in the refrigerant of the cooling circuit 100 after maintenance is suppressed.

More specifically, the air bleeding process of the present embodiment is started when the operation panel is operated to set the air bleeding mode after the ion exchange resin of the ion exchanger 140 is replaced. First, the water pump 110 is driven with the three-way valve 160 set on the ion exchanger flow path 106 side, and the refrigerant is circulated in the direction of arrow A1 in FIG. As a result, of the air contained in the ion exchange resin, the air flowing from the merging portion 107 to the water pump 110 side has the refrigerant circulated in the basic flow path 102 and the ion exchanger flow path 106 along the arrow A1. During that time, it flows from the flow paths 172 and 174 to the reserve tank 170 and is gradually discharged from the reserve tank 170. During this period, the air flowing back in the radiator flow path 104 in the direction of arrow A2 in FIG. 2 is not discharged from the reserve tank 170 because the refrigerant does not flow in the radiator flow path 104, and enters the radiator flow path 104 or the radiator 130. Staying.

After that, in order to expel the air flowing back through the radiator flow path 104 from the radiator flow path 104, the three-way valve 160 is set on the radiator flow path 104 side, and the water pump 110 is driven. FIG. 3 is a schematic view showing the flow of the refrigerant when the three-way valve 160 is set on the radiator flow path 104 side and the water pump 110 is driven. When the three-way valve 160 is set on the radiator flow path 104 side and the water pump 110 is driven, the refrigerant is circulated in the direction of arrow A3 in FIG. Of the air contained in the ion exchange resin, the air flowing back in the radiator flow path 104 in the direction of arrow A2 in FIG. 2 and staying in the radiator flow path 104 is such that the refrigerant flows in the direction of arrow A3 shown in FIG. While the refrigerant circulates in the basic flow path 102 and the radiator flow path 104, it flows from the flow paths 172, 174, 176 to the reserve tank 170 and is gradually discharged from the reserve tank 170. When the air remaining in the radiator flow path 104 is discharged from the reserve tank 170, the air bleeding process is completed.

As described above, according to the present embodiment, even when air is mixed in the refrigerant during maintenance and the mixed air flows backward in the flow path connected from above in the direction of gravity with respect to the merging portion, the mixed air is mixed. The air is surely discharged from the cooling circuit 100. Therefore, it is possible to prevent the cooling efficiency of the fuel cell 120 from being lowered due to the mixing of air.

When the three-way valve 160 is set on the radiator flow path 104 side in the air bleeding process, the flow rate of the refrigerant flowing into the radiator flow path 104 is larger than the flow rate of the refrigerant flowing into the ion exchanger flow path 106. It suffices if the opening degree of the valve 160 is controlled. As a result, the air remaining after flowing back through the radiator flow path 104 in the direction of arrow A2 in FIG. 2 is discharged from the radiator flow path 104 by the refrigerant flowing through the radiator flow path 104, and is discharged in the direction of arrow A3 in FIG. It is discharged from the reserve tank 170 in the process of circulation. Therefore, it is not necessary to flow all of the refrigerant flowing through the three-way valve 160 to the radiator flow path 104 side, and a part of the refrigerant may flow to the ion exchanger flow path 106 side.

Next, the air bleeding process performed at the time of maintenance of the cooling system 1000 will be described with reference to the flowchart of FIG. This process is performed by the ECU 300 at predetermined intervals. First, it is determined whether or not the air bleeding trigger is detected (step S10). Specifically, in step S10, after the ion exchange resin is replaced, it is determined whether or not the operation panel is operated to set the air bleeding mode.

When the air bleeding trigger is detected in step S10, the three-way valve 160 is set on the ion exchanger flow path 106 side, and the water pump 110 is driven (step S12). As a result, the air contained in the ion exchange resin circulates in the direction of arrow A1 in FIG. 2 and is gradually discharged from the reserve tank 170. On the other hand, if the air bleeding trigger is not detected, it waits in step S10.

After step S12, it is determined whether or not a predetermined time has elapsed (step S14). During this predetermined time, after the three-way valve 160 is set on the ion exchanger flow path 106 side and the water pump 110 is driven, the air contained in the ion exchange resin from the confluence 107 in the direction of arrow A1 in FIG. Corresponds to the time when the air flowing into the reserve tank 170 is discharged from the reserve tank 170. The predetermined time is, for example, a value obtained in advance by an experiment, and is, for example, about 10 minutes.

When the predetermined time has elapsed in step S14, the three-way valve 160 is set on the radiator flow path 104 side, and the water pump 110 is driven (step S16). As a result, the air remaining in the radiator flow path 104 flows from the flow paths 172, 174, 176 while the refrigerant flows in the direction of arrow A3 shown in FIG. 3 and the refrigerant circulates between the basic flow path 102 and the radiator flow path 104. It flows into the reserve tank 170 and is gradually discharged from the reserve tank 170. On the other hand, if the predetermined time has not elapsed, the process waits in step S14.

After step S16, it is determined whether or not a predetermined time has elapsed (step S18). This predetermined time corresponds to the time when the air remaining on the radiator flow path 104 side is discharged from the reserve tank 170 after the three-way valve 160 is set on the radiator flow path 104 side and the water pump 110 is driven. The predetermined time here is also, for example, a value obtained in advance by an experiment.

When the predetermined time has elapsed in step S18, the air bleeding process is terminated (step S20). On the other hand, if the predetermined time has not elapsed, the process waits in step S18.

(Modification example)
FIG. 5 is a diagram showing the configuration of the cooling system 1000 according to the modified example of the present embodiment, and shows a configuration example in which the ion exchanger 140 is provided between the confluence portion 107 and the water pump 110. In this configuration example, the ion exchanger flow path 106 shown in FIGS. 1 to 3 is a bypass flow path 109 that bypasses the radiator 130.

Also in the configuration example shown in FIG. 5, the pipe of the radiator flow path 104 extends upward from the merging portion 107 in the direction of gravity. Therefore, when the ion exchange resin of the ion exchanger 140 is replaced, the air discharged from the ion exchange resin may flow back in the radiator flow path 104 in the direction of arrow A2 due to buoyancy.

Therefore, even in the configuration example shown in FIG. 5, in the air bleeding process during maintenance, the water pump 110 is first driven with the three-way valve 160 set on the bypass flow path 109 side, and is included in the ion exchange resin. The air that had been collected is circulated in the direction of arrow A1 in FIG. 5 and gradually discharged from the reserve tank 170.

After that, in order to expel the air flowing back through the radiator flow path 104 from the radiator flow path 104, the three-way valve 160 is set on the radiator flow path 104 side, and the water pump 110 is driven. As a result, of the air contained in the ion exchange resin, the air flowing back in the radiator flow path 104 in the direction of arrow A2 in FIG. 5 and staying in the radiator flow path 104 has the refrigerant flowing through the basic flow path 102 and the radiator flow. While circulating in the road 104, it flows into the reserve tank 170 and is gradually discharged from the reserve tank 170.

Further, the ion exchanger 140 may be provided between the radiator 130 and the merging portion 107. Also in this case, the three-way valve 160 is set on the radiator flow path 104 side during the air bleeding process, and the water pump 110 is driven so that the radiator flow path 104 flows backward and stays in the radiator flow path 104. The air is discharged from the reserve tank 170 while the refrigerant circulates in the basic flow path 102 and the radiator flow path 104.

As described above, according to the present embodiment, when the radiator flow path 104 is connected to the merging portion 107 from above in the direction of gravity, the air mixed in the refrigerant is buoyant from the merging portion 107 to the radiator flow path. Even if the 104 is backflowed, the air staying in the radiator flow path 104 is suppressed. Therefore, it is possible to prevent the cooling efficiency of the fuel cell 120 from being lowered due to the mixed air.

100 Cooling circuit 102 Basic flow path 104 Radiator flow path 106 Ion exchanger flow path 107 Confluence 108 Intercooler flow path 109 Bypass flow path 110 Water pump 120 Fuel cell 130 Radiator 132 Blower fan 140 Ion exchanger 150 Intercooler 160 Three-way valve 170 Reserve tank 172,174,176 Flow path 180,182 Temperature sensor 200 Air conditioning heat linkage circuit 300 Electronic control unit (ECU)
400 Air contamination detector 1000 Cooling system

Claims (1)

The first flow path through which the liquid refrigerant that cools the fuel cell flows, and
A second flow path that branches from the first flow path at the branch portion and merges with the first flow path at the merging portion.
A valve device that controls the flow rate of the refrigerant flowing in each of the first flow path and the second flow path.
A control unit that controls the opening degree of the valve device and
A fuel cell cooling system including at least a detection unit capable of detecting the inclusion of gas in the refrigerant.
The first flow path is a flow path connected to the confluence from above in the direction of gravity.
When the detection unit detects that gas has been mixed into the refrigerant, the control unit has a flow rate of the refrigerant flowing into the first flow path larger than the flow rate of the refrigerant flowing into the second flow path. A fuel cell cooling system that controls the opening degree of the valve device so as to be.

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