JP2020053287A - Fuel cell system - Google Patents

Abstract

To provide a new and improved fuel cell system capable of suppressing deterioration of an ion exchanger provided in a cooling circuit of the fuel cell system to extend a life of the ion exchanger.SOLUTION: The fuel cell system includes: a fuel cell; a first cooling water circuit formed so that cooling water passing through the fuel cell can circulate; a second cooling water circuit, including an ion exchanger, formed so that the cooling water can circulate; and a channel switching valve for switching connection and disconnection between the first cooling water circuit and the second cooling water circuit.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel cell system.

  The cooling circuit of the fuel cell system is provided with an ion exchanger for removing ions in the cooling water flowing through the cooling circuit. The ion exchanger includes, for example, an ion exchange resin filter provided so that cooling water can pass therethrough. The ion exchange resin filter has a function of adsorbing and removing ions in the cooling water. By removing ions in the cooling water by using the ion exchanger, corrosion of metal and deterioration of the function of the fuel cell can be suppressed, and electrical insulation of the cooling water can be enhanced to prevent electric leakage.

JP 2013-233500 A

  Here, when cooling water passes through the ion exchanger, ion exchange is always performed in the ion exchange resin filter. For this reason, the ion removal capability of the ion exchanger may be reduced in a short period of time.

  Further, the fuel cell generates heat due to a chemical reaction when generating power. If the temperature of the cooling water passing through the fuel cell exceeds the heat-resistant temperature of the ion exchange resin, the ion exchange resin filter may be deteriorated. Further, increasing the power generation efficiency of the fuel cell involves an increase in the reaction temperature. Therefore, the durability of the ion-exchange resin filter may become an issue in the future.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress deterioration of an ion exchanger provided in a cooling circuit of a fuel cell system and extend the life of the ion exchanger. It is to provide a new and improved fuel cell system which can be used.

  According to one aspect of the present invention, there is provided a cooling water comprising a fuel cell, a first cooling water circuit formed so that cooling water passing through the fuel cell can be circulated, and an ion exchanger. A fuel cell system comprising: a second cooling water circuit formed so as to be able to circulate; and a flow path switching valve that switches connection and disconnection between the first cooling water circuit and the second cooling water circuit. Is done.

  When connecting the first cooling water circuit and the second cooling water circuit, a third cooling water circuit is configured by a part of the first cooling water circuit and a part of the second cooling water circuit, The ion exchanger may be provided in a portion of the second cooling water circuit that does not form the third cooling water circuit.

  The second cooling water circuit may include a buffer tank that stores the cooling water.

  The second cooling water circuit may include a cooler that cools the cooling water.

  At least one of the first cooling water circuit and the second cooling water circuit may include a conductivity detector that detects a conductivity of the cooling water.

  A control device that controls the operation of the flow path switching valve, wherein the control device is configured such that the cooling water flowing through the first cooling water circuit is in a state where the first cooling water circuit and the second cooling water circuit are shut off. The first cooling water circuit and the second cooling water circuit may be connected when the conductivity exceeds the first threshold.

  The control device may circulate the cooling water through the second cooling water circuit in a state where the first cooling water circuit and the second cooling water circuit are shut off.

  The control device may stop the circulation of the cooling water in the second cooling water circuit when the conductivity of the cooling water circulating in the second cooling water circuit is less than a second threshold.

  The fuel cell system may be mounted on a fuel cell vehicle.

  The fuel cell system may be mounted on a fuel cell vehicle, and the second cooling water circuit may be connected to a cooling circuit of a secondary battery that is a power source of a drive motor of the fuel cell vehicle.

  As described above, according to the present invention, it is possible to suppress the deterioration of the ion exchanger provided in the cooling circuit of the fuel cell system and extend the life of the ion exchanger.

1 is a schematic diagram illustrating a configuration example of a fuel cell vehicle to which a fuel cell system according to an embodiment can be applied. FIG. 3 is a schematic diagram illustrating a configuration example of a cooling circuit of the fuel cell system according to the same embodiment. FIG. 3 is a schematic diagram showing a state where a first cooling water circuit and a second cooling water circuit of the fuel cell system according to the embodiment are connected. FIG. 3 is a block diagram illustrating a configuration example of a control device of the fuel cell system according to the embodiment. 5 is a flowchart illustrating a control process performed by the control device. It is a flowchart which shows the switching process of the cooling circuit by a control apparatus. It is a schematic diagram which shows the example of a structure of the cooling circuit of the fuel cell system which concerns on a 1st modification. FIG. 9 is a schematic diagram showing a state in which a first cooling water circuit and a second cooling water circuit of a fuel cell system according to a first modification are connected. FIG. 9 is a schematic diagram illustrating a configuration example of a cooling circuit of a fuel cell system according to a second modification. FIG. 9 is a schematic diagram illustrating a state in which a first cooling water circuit and a second cooling water circuit of a fuel cell system according to a second modification are connected. FIG. 9 is a schematic diagram illustrating a configuration example of a fuel cell system according to a third modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<1. Configuration example of fuel cell vehicle>
First, a configuration example of a fuel cell vehicle to which a fuel cell system according to an embodiment of the present invention can be applied will be described. FIG. 1 is a schematic diagram illustrating a configuration example of the fuel cell vehicle 1. The fuel cell vehicle 1 includes a fuel cell system 100 including a fuel cell 20, a hydrogen tank 10, a secondary battery 30, a drive motor 40, a drive wheel 50, a DCDC converter 60, an inverter 70, and a control device 90. And

  In the following description, the fuel cell vehicle 1 travels mainly by driving the drive motor 40 with power supplied from the secondary battery 30, and when the remaining capacity SOC of the secondary battery 30 decreases, the fuel cell vehicle 1 A case will be described as an example where the vehicle is a fuel cell range extender vehicle that charges the secondary battery 30 with the generated power. However, the fuel cell vehicle 1 to which the fuel cell system according to the present embodiment is applicable is not limited to a fuel cell range extender vehicle.

  The fuel cell vehicle 1 basically drives the drive motor 40 using the electric power supplied from the secondary battery 30 to obtain the driving torque of the vehicle. The fuel cell vehicle 1 can continue running by charging the secondary battery 30 using the power generated by the fuel cell 20 when the state of charge SOC of the secondary battery 30 decreases. The fuel cell vehicle 1 supplements the power by supplying the power generated by the fuel cell 20 to the drive motor 40 when the required load on the vehicle is high and the power supplied from the secondary battery 30 alone is insufficient.

  The fuel cell 20 mounted on the fuel cell vehicle 1 is a generator (range extender) for extending the cruising distance of the fuel cell vehicle 1. Therefore, the output or capacity may be smaller than that of a fuel cell mounted in a fuel cell vehicle that is not a fuel cell range extender type that mainly uses the power generated by the fuel cell.

  The hydrogen tank 10 is filled with high-pressure hydrogen supplied to the fuel cell 20. The number of hydrogen tanks 10 is not particularly limited. The number of the hydrogen tanks 10 may be one or a plurality.

  The fuel cell 20 generates power by reacting hydrogen gas and oxygen gas. The hydrogen tank 10 and the fuel cell 20 are connected via a pipe 12, and hydrogen gas is supplied from the hydrogen tank 10 to the fuel cell 20. Air as oxygen gas is supplied to the fuel cell 20 by a compressor (not shown) or the like. The fuel cell 20 may be a known fuel cell 20 as long as it has the above functions.

  The fuel cell 20 includes a fuel cell stack (not shown) having a plurality of fuel cells. A hydrogen tank 10 is connected to the fuel cell stack via a pipe 12. A control valve (not shown) for adjusting the pressure of the hydrogen gas is provided in the middle of the pipe 12. For example, high-pressure hydrogen is held in the hydrogen tank 10, and the high-pressure hydrogen is reduced in pressure, and hydrogen gas is supplied to the fuel cell 20. However, the hydrogen gas may be extracted from the hydrogen storage alloy or the liquid in which hydrogen is dissolved, and supplied to the fuel cell 20 by being pressurized by a pressure pump. The fuel cell stack is supplied with air pumped by a compressor or the like.

  The air supplied to the fuel cell stack reacts with hydrogen gas when passing through each fuel cell. Excess air and water vapor generated by the reaction are exhausted. Further, the hydrogen gas supplied to the fuel cell stack reacts with oxygen in the air when passing through each fuel cell. Excess hydrogen gas is exhausted through a purge valve (not shown). Alternatively, part of the surplus hydrogen gas may be returned to the upstream side of the fuel cell stack via a circulation pump (not shown).

  Driving of a motor pump, a control valve, a compressor, a circulation pump, and a purge valve (not shown) is controlled by the control device 90.

  The DCDC converter 60 performs voltage conversion of the generated power output from the fuel cell 20. The power generated by the fuel cell 20 is converted into a voltage with the DC power unchanged. In the present embodiment, the drive of the DCDC converter 60 is controlled by the control device 90. The DCDC converter 60 performs, for example, unidirectional power conversion from the fuel cell 20 side to the secondary battery 30 or the inverter 70 side. The DCDC converter 60 may be a known power converter as long as it has the above functions.

  The secondary battery 30 is a power supply source of the drive motor 40 and stores power supplied to the drive motor 40. The secondary battery 30 supplies DC power of a predetermined output voltage (battery voltage) to the inverter 70. Further, the secondary battery 30 is capable of charging the generated power of the fuel cell 20 and the regenerated power of the drive motor 40. The power generated by the fuel cell 20 or the power generated by the drive motor 40 is supplied to the secondary battery 30 as DC power and charged.

  In addition, the secondary battery 30 may be connected to the DCDC converter 60 or the inverter 70 via the power converter 65 shown by a virtual line in FIG. In this case, the power converter 65 may convert the output voltage of the secondary battery 30 and supply it to the inverter 70. Further, the power converter 65 may convert the voltage of the power generated by the fuel cell 20 and the voltage of the regenerative power generated by the drive motor 40 into the power for charging the secondary battery 30.

  In addition, the secondary battery 30 is configured to be connectable to an external power supply via a charging circuit and a charging connector (not shown), and can be charged from the external power supply. Further, the power supplied from the secondary battery 30 may be able to charge an auxiliary battery (not shown). For example, the power supplied from the secondary battery 30 may be stepped down by a step-down converter to charge the auxiliary battery.

  As the secondary battery 30, for example, a lithium ion battery, a lithium ion polymer battery, a nickel hydride battery, a nickel cadmium battery, or a lead storage battery is used. However, the secondary battery 30 may be a secondary battery other than these.

  The secondary battery 30 is provided with a battery management device (BMS: Battery Management System) 35. For example, the battery management device 35 calculates the output voltage (battery voltage) and the remaining capacity SOC of the secondary battery 30 and outputs a signal indicating the information to the control device 90.

  The drive motor 40 is driven by the supplied electric power and outputs a drive torque of the vehicle. The drive motor 40 is, for example, a three-phase AC motor, and is driven (powered drive) using power supplied from the secondary battery 30 and the fuel cell 20 to generate a drive torque. Further, the drive motor 40 may have a function as a generator (regeneration function) that is regeneratively driven when the vehicle is decelerated and generates electric power using the rotational torque of the drive wheels 50. The drive motor 40 may be a known drive motor 40 as long as it has the above functions.

  Inverter 70 converts DC power supplied from fuel cell 20 or secondary battery 30 into AC power. Further, inverter 70 converts the AC power regenerated by drive motor 40 into DC power. The drive of inverter 70 is controlled by control device 90.

  Specifically, when driving the drive motor 40 in power running, the control device 90 controls the inverter 70 to convert DC power into AC power, supplies the AC power to the drive motor 40, and drives the drive motor 40. When the drive motor 40 is to be regeneratively driven, the control device 90 controls the inverter 70 to convert the AC power generated by the drive motor 40 into DC power, and to use the secondary battery 30 as charging power for the secondary battery 30. To supply. The inverter 70 performs bidirectional power conversion from the fuel cell 20 and the secondary battery 30 to the drive motor 40 and from the drive motor 40 to the secondary battery 30. Inverter 70 may be a known power converter as long as it has the above functions.

  Note that the number of inverters 70 is not limited to one, and a plurality of power converters may be provided. The number of drive motors 40 connected to one inverter 70 is not limited to one, and a plurality of drive motors 40 may be connected to one inverter 70.

<2. Configuration example of fuel cell system>
Next, a configuration example of the fuel cell system 100 according to the present embodiment will be described. The fuel cell system 100 includes a fuel cell 20, a radiator 101, an ion exchanger 103, a first pump 105, a second pump 107, a buffer tank 109, a heat exchanger 115, a first flow The apparatus includes a path switching valve 111, a second flow path switching valve 113, a first conductivity detector 117, and a second conductivity detector 119.

  The first pump 105, the radiator 101, the first conductivity detector 117, and the first flow path switching valve 111 are provided in a first cooling water circuit 121 passing through the fuel cell 20. The first cooling water circuit 121 is disposed so as to pass through the fuel cell 20 on the way. In the fuel cell 20, the first cooling water circuit 121 is formed so as to pass through the fuel cell stack. The cooling water pumped by the first pump 105 circulates through the first cooling water circuit 121 so as to pass through the radiator 101, the first flow path switching valve 111, the fuel cell 20, and the first pump 105 in this order. It is possible.

  The second pump 107, the ion exchanger 103, the second conductivity detector 119, the buffer tank 109, the heat exchanger 115, and the second flow path switching valve 113 are provided in the second cooling water circuit 123. I have. The cooling water pumped by the second pump 107 passes through the ion exchanger 103, the buffer tank 109, the heat exchanger, the second flow path switching valve 113, and the second pump 107 in this order so as to pass through the second pump 107. The cooling water circuit 123 can be circulated. The second cooling water circuit 123 has a function as an ion exchange circuit for reducing the ion concentration of the cooling water.

  The radiator 101 is a heat exchange device, and cools the cooling water that has passed through the radiator 101 by releasing heat. The radiator 101 may be a known radiator. Further, instead of the radiator 101, another cooling device capable of cooling the cooling water may be used. In the first cooling water circuit 121, the radiator 101 is located on the downstream side of the connection between the first cooling water circuit 121 and the first connection passage 123 and on the upstream side of the first flow path switching valve 111. May be arranged at any position other than the portion 121a.

  The ion exchanger 103 includes an ion exchange resin filter, and removes ions in the cooling water passing through the ion exchanger 103. Thereby, the ion concentration of the cooling water decreases, and the conductivity of the cooling water can be reduced. The ion exchanger 103 may be a known ion exchanger. In the second cooling water circuit 123, the ion exchanger 103 is located on the downstream side of the second flow path switching valve 113 and at a position closer to the connection between the second cooling water circuit 123 and the second connection passage 127. It is arranged in the upstream portion 123a.

  The buffer tank 109 is a tank having a predetermined capacity capable of storing cooling water. The buffer tank 109 is provided mainly for accumulating cooling water whose ion concentration has been reduced by the ion exchanger 103. That is, a predetermined amount of cooling water having a low ion concentration is held in the second cooling water circuit 123. The buffer tank 109 is provided so that the capacity of the cooling water circulating in the second cooling water circuit 123 satisfies the amount of water necessary for lowering the conductivity of the cooling water circulating in the first cooling water circuit 121. It is preferable that the capacity of the buffer tank 109 is designed to be equal to or larger than the capacity of the cooling water circulating in the first cooling water circuit 121, for example.

  The heat exchanger 115 is an embodiment of a cooler that cools the cooling water, and cools the cooling water passing through the heat exchanger 115 by releasing heat. The radiator 101 provided in the first cooling water circuit 121 cools the cooling water that has passed through the fuel cell 20 and raised in temperature, whereas the heat exchanger 115 mainly includes a second cooling water circuit. This suppresses a rise in the temperature of the cooling water flowing through 123. For this reason, the cooling capacity of the heat exchanger 115 may be smaller than the cooling capacity of the radiator 101, and the temperature of the cooling water flowing through the second cooling water circuit 123 is equal to or lower than the heat-resistant temperature (for example, 30 ° C.) of the ion exchanger 103. Should be reduced to The buffer tank 109 and the heat exchanger 115 may be arranged at any position in the second cooling water circuit 123 as long as the position is other than the portion 123a.

  The first conductivity detector 117 and the second conductivity detector 119 detect the conductivity of the cooling water at the respective installation positions. The first conductivity detector 117 detects the conductivity of the cooling water circulating in the first cooling water circuit 121. The second conductivity detector 119 detects the conductivity of the cooling water circulating in the second cooling water circuit 123. The first conductivity detector 117 and the second conductivity detector 119 may be known conductivity meters such as an electric conductivity meter or an electromagnetic conductivity meter. A signal indicating information on the conductivity detected by the first conductivity detector 117 and the second conductivity detector 119 is transmitted to the control device 90.

  The first conductivity detector 117 may be arranged at any position in the first cooling water circuit 121 as long as the position is other than the portion 121a. Further, the second conductivity detector 119 may be disposed at any position in the second cooling water circuit 123 as long as the position is other than the portion 123a.

  The first pump 105 and the second pump 107 respectively pump cooling water and circulate the cooling water. The driving of the first pump 105 and the second pump 107 is controlled by the control device 90, respectively. Each of the first pump 105 and the second pump 107 may be a known liquid feed pump.

  The first pump 105 provided in the first cooling water circuit 121 is provided downstream of the fuel cell 20. By driving the first pump 105, the cooling water circulates so as to pass through the fuel cell 20, and the fuel cell 20 is cooled. The first pump 105 may be arranged at any position in the first cooling water circuit 121 as long as it is a position other than the portion 121a.

  The second pump 107 provided in the second cooling water circuit 123 is provided on the upstream side of the ion exchanger 103. Therefore, by driving the second pump 107, the cooling water circulates so as to pass through the ion exchanger 103, and the ion concentration of the cooling water can be reduced. Since the flow rate of the cooling water circulating through the second cooling water circuit 123 may be smaller than the flow rate of the cooling water circulating through the first cooling water circuit 121, the second pump 107 is A pump having an output smaller than the rated output may be used. The second pump 107 may be arranged on the downstream side of the ion exchanger 103 as long as it is the above-mentioned portion 123a in the second cooling water circuit 123.

  The first cooling water circuit 121 and the second cooling water circuit 123 are connected via a first connection passage 125 and a second connection passage 127. The first flow path switching valve 111 is provided at a connection portion between the first cooling water circuit 121 and the second connection passage 127. The second flow path switching valve 113 is provided at a connection portion between the second cooling water circuit 123 and the first connection passage 127. The first flow path switching valve 111 and the second flow path switching valve 113 are three-way valves. The driving of the first flow path switching valve 111 and the second flow path switching valve 113 is controlled by the control device 90.

  The first flow path switching valve 111 has a circulation mode in which the second connection passage 127 is closed while the portion 121a of the first cooling water circuit 121 is opened, and a second circulation passage in which the second connection passage 127 is opened while the second connection passage 127 is opened. The connection mode in which the portion 121a of the one cooling water circuit 121 is closed can be switched. In addition, the second flow path switching valve 113 has a circulation mode in which the first connection passage 125 is closed while the portion 123a of the second cooling water circuit 123 is opened, and a second circulation passage mode in which the first connection passage 125 is opened. Thus, the connection mode in which the portion 123a of the second cooling water circuit 123 is closed can be switched.

  When the first flow path switching valve 111 and the second flow path switching valve 113 are both set in the circulation mode, two independent first cooling water circuits 121 and second cooling water circuits 123 are formed. Is done. On the other hand, when both the first flow path switching valve 111 and the second flow path switching valve 113 are set to the connection mode, the first cooling is performed via the first connection passage 125 and the second connection passage 127. The water circuit 121 and the second cooling water circuit 123 are connected to form a third cooling water circuit (131 in FIG. 3).

  The cooling water circuit formed will be described with reference to FIGS. FIG. 2 shows a state where both the first flow path switching valve 111 and the second flow path switching valve 113 are set to the circulation mode. In this case, the cooling water pumped by the first pump 105 circulates in the first cooling water circuit 121. The cooling water receives heat from the fuel cell 20 when passing through the fuel cell 20, thereby lowering the temperature of the fuel cell 20. The heated cooling water radiates heat by passing through the radiator 101, and passes through the fuel cell 20 again in a state where the temperature is lowered. In this case, the cooling water for cooling the fuel cell 20 circulates in the first cooling water circuit 121 without passing through the ion exchanger 103.

  Further, in the second cooling water circuit 123, the cooling water pumped by the second pump 107 can be circulated. The cooling water circulating in the second cooling water circuit 123 passes through the ion exchanger 103, so that the ion concentration decreases. The cooling water circulating in the second cooling water circuit 123 is stored in the buffer tank 109 on the way.

  FIG. 3 shows a state where both the first flow path switching valve 111 and the second flow path switching valve 113 are set to the connection mode. In this case, the third cooling returning from the first cooling water circuit 121 to the first cooling water circuit 121 again via the first connection passage 125, the second cooling water circuit 123, and the second connection passage 127. A water circuit 131 is formed. In the third cooling water circuit 131, the cooling water pumped by the first pump 105 can be circulated.

  The cooling water pumped by the first pump 105 passes through the radiator 101, the heat exchanger 115, the buffer tank 109, and the fuel cell 20, and returns to the first pump 105 again. At this time, the cooling water having a low conductivity stored in the buffer tank 109 is supplied to the first cooling water circuit 121. As a result, the cooling water in the first cooling water circuit 121 is replaced with cooling water having low conductivity.

<3. Configuration example of control device>
Next, a configuration example of the control device 90 will be described. FIG. 4 is a block diagram illustrating a configuration example of a control device 90 that controls the fuel cell system 100 according to the present embodiment. FIG. 4 shows a part related to the function of controlling the cooling water circuit in the functional configuration of the control device 90.

  The control device 90 includes, for example, one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and a storage device that stores software programs, control parameters, acquired information, and the like. The storage device may include a random access memory (RAM) and a read only memory (ROM), or may include another storage medium such as a CD-ROM or a storage device.

  The control device 90 includes a conductivity detection section 91, a determination section 92, a first pump drive section 93, a second pump drive section 94, a first flow path switching valve drive section 95, and a second flow path switching valve drive. A part 96 is provided. These units may be functions realized by execution of a software program by a processor. In addition, the first pump driving section 93, the second pump driving section 94, the first flow path switching valve driving section 95, and the second flow path switching valve driving section 96 are respectively composed of the first pump 105, the second pump And a drive circuit that outputs a drive signal to the pump 107, the first flow path switching valve 111, and the second flow path switching valve 113.

  Note that a part or all of the control device 90 may be configured of an updatable device such as firmware in addition to an example configured of a CPU or an MPU. Alternatively, a part or all of the control device 90 may be a program module or the like executed by a command from a CPU or the like. Control device 90 may be constituted by a plurality of control devices configured to be able to communicate with each other.

  The conductivity detection unit 91 detects the first conductivity detector 117 and the second conductivity based on output signals transmitted from the first conductivity detector 117 and the second conductivity detector 119, respectively. The electric conductivity of the cooling water at each installation position of the heater 119 is detected.

  The determination unit 92 determines whether switching of the cooling water circuit is necessary based on the conductivity of the cooling water detected by the conductivity detection unit 91. For example, when the conductivity of the cooling water detected by the first conductivity detector 117 is equal to or less than a predetermined first threshold, the determination unit 92 switches the first cooling water circuit 121 to the second cooling water circuit. 123 is kept independent. On the other hand, when the conductivity of the cooling water detected by the first conductivity detector 117 exceeds the first threshold, the first cooling water circuit 121 and the second cooling water circuit 123 are connected. The third cooling water circuit 131 is formed.

  Further, the determination unit 92 determines that the conductivity of the cooling water detected by the second conductivity detector 119 is a predetermined value in a state where the first cooling water circuit 121 and the second cooling water circuit 123 are independent of each other. If the second threshold value is exceeded, a process of driving the second pump 107 to reduce the ion concentration of the cooling water circulating in the second cooling water circuit 123 is executed. The second threshold value may be the same value as the first threshold value or may be a different value.

  The first pump driving section 93 controls the driving of the first pump 105 provided in the first cooling water circuit 121. For example, the first pump driving unit 93 may always drive the first pump 105 while the fuel cell system 100 is operating.

  The second pump driving section 94 controls the driving of a second pump 107 provided in the second cooling water circuit 123. For example, the second pump driving unit 94 controls the driving of the second pump 107 based on the instruction of the determining unit 92.

  The first flow path switching valve driving section 95 controls the driving of the first flow path switching valve 111 provided in the first cooling water circuit 121. Specifically, the first flow path switching valve driving section 95 sets the first flow path switching valve 111 to the circulation mode or the connection mode based on the instruction of the determination section 92.

  The second flow path switching valve driving section 96 controls the driving of the second flow path switching valve 113 provided in the second cooling water circuit 123. Specifically, the second flow path switching valve driving section 96 sets the second flow path switching valve 113 to the circulation mode or the connection mode based on the instruction of the determination section 92.

<4. Control Process of Cooling Water Circuit of Fuel Cell System>
Next, the control processing operation of the cooling water circuit by the control device 90 will be described with reference to FIGS. The flowcharts shown in FIGS. 5 and 6 are executed, for example, after the fuel cell system 100 is started.

  As shown in FIG. 5, after the start of the fuel cell system 100, the first flow path switching valve driving section 95 and the second flow path switching valve driving section 96 transmit the first flow path switching valve 111 and the second flow path switching valve 96, respectively. Is set to the circulation mode (step S11). Specifically, the first flow path switching valve driving section 95 closes the second connection passage 127 by the first flow path switching valve 111 and opens the portion 121a of the first cooling water circuit 121. The second flow path switching valve driving section 96 closes the first connection passage 125 by the second flow path switching valve 113 while opening the portion 123 a of the second cooling water circuit 123.

  Next, the first pump driving section 93 drives the first pump 105 (Step S13). Thereby, the cooling water circulates in the first cooling water circuit 121, and the rise in the temperature of the fuel cell 20 can be suppressed. The output of the first pump 105 may be a constant value or a variable value. For example, when it is desired to lower the temperature of the fuel cell 20, the air volume of the radiator 101 is increased to increase the heat radiation amount of the cooling water circulating in the first cooling water circuit 121. Thereby, the temperature of the fuel cell 20 can be rapidly reduced.

  Next, after the circulation of the cooling water in the first cooling water circuit 121 is started, the control device 90 starts the switching control of the cooling water circuit (step S15). Thereafter, until the start of the fuel cell system 100 is stopped, the control device 90 continues the switching control of the cooling water circuit. FIG. 6 shows a flowchart of the switching control of the cooling water circuit executed in step S15.

  First, the determination unit 92 determines whether switching of the cooling water circuit is necessary (step S21). In the present embodiment, the determination unit 92 determines the conductivity of the cooling water detected by the conductivity detection unit 91 based on the output signal of the first conductivity detector 117 (hereinafter, also referred to as “first conductivity”). .) Exceeds a first threshold set in advance.

  When the first electric conductivity is equal to or less than the first threshold value, the necessity of decreasing the electric conductivity of the cooling water circulating in the first cooling water circuit 121 is small, and therefore, the determination unit 92 sets the first cooling water circuit 121 It is determined that the connection with the second cooling water circuit 123 is unnecessary. On the other hand, when the first conductivity exceeds the first threshold value, it is necessary to reduce the conductivity of the cooling water circulating in the first cooling water circuit 121. It is determined that connection between the water circuit 121 and the second cooling water circuit 123 is necessary.

  In the fuel cell system 100, the conductivity of the cooling water only needs to be kept low enough not to give an electric shock to the human body, and it is not essential to lower the conductivity excessively. In consideration of this point, the first threshold is set to an appropriate value.

  Alternatively, the determination unit 92 may determine whether the temperature inside the fuel cell 20 is excessively high as the circuit switching necessity determination in step S21. Specifically, the determination unit 92 may determine whether or not the temperature in the fuel cell 20 exceeds a heat-resistant threshold value at which it is possible to determine whether or not the temperature is excessively increased.

  When the temperature in the fuel cell 20 exceeds the heat resistance threshold, the low-temperature cooling water stored in the buffer tank 109 provided in the second cooling water circuit 123 is supplied to the first cooling water circuit 121. Since the fuel cell 20 can be rapidly cooled, the determination unit 92 determines that connection between the first cooling water circuit 121 and the second cooling water circuit 123 is necessary. On the other hand, when the temperature in the fuel cell 20 is equal to or lower than the heat resistance threshold, the determination unit 92 determines that the connection between the first cooling water circuit 121 and the second cooling water circuit 123 is unnecessary.

  Next, the determination unit 92 determines whether it is necessary to connect the first cooling water circuit 121 and the second cooling water circuit 123 as a result of the necessity of switching the cooling water circuit (step S23). . When there is no need to connect the first cooling water circuit 121 and the second cooling water circuit 123 (S23 / No), the determination unit 92 determines whether the first flow switching valve driving unit 95 and the second flow channel have been connected. The switching valve driving section 96 is instructed to set the first flow path switching valve 111 and the second flow path switching valve 113 to the circulation mode (step S29).

  In accordance with the instruction from the determination unit 92, the first flow path switching valve driving unit 95 and the second flow path switching valve driving unit 96 are connected to the first flow path switching valve 111 and the second flow path switching valve 113, respectively. The first flow path switching valve 111 and the second flow path switching valve 113 are driven so as to be in the circulation mode. As a result, the first cooling water circuit 121 and the second cooling water circuit 123 are held independently of each other.

  In this state, the cooling water for cooling the fuel cell 20 circulates in the first cooling water circuit 121. Since all of the cooling water circulating in the first cooling water circuit 121 passes through the radiator 101, the cooling water heated by the exhaust heat of the fuel cell 20 is efficiently cooled, and the cooling efficiency of the fuel cell 20 is improved. Can be planned.

  Next, the determination unit 92 determines whether ion removal is necessary (step S30). In the present embodiment, the determination unit 92 determines the conductivity of the cooling water detected by the conductivity detection unit 91 based on the output signal of the second conductivity detector 119 (hereinafter, also referred to as “second conductivity”). .) Exceeds a second threshold value set in advance.

  When the second conductivity is equal to or less than the second threshold value, it is not necessary to reduce the ion concentration of the cooling water held in the second cooling water circuit 123. Therefore, the determination unit 92 does not need to remove ions. Is determined. On the other hand, when the second conductivity exceeds the second threshold, it is necessary to reduce the ion concentration of the cooling water held in the second cooling water circuit 123, so the determination unit 92 needs to remove ions. It is determined that there is.

  Next, as a result of the ion removal necessity determination, the determination unit 92 determines whether it is necessary to perform ion removal (step S31). If the conductivity (second conductivity) of the cooling water held in the second cooling water circuit 123 is high and it is necessary to perform ion removal of the cooling water (S31 / Yes), the determination unit 92 determines Is instructed to drive the second pump 107 (step S33).

  The second pump driving section 94 drives the second pump 107 according to the instruction of the determining section 92. Thereby, the cooling water circulates through the second cooling water circuit 123, and the ion concentration of the cooling water is reduced by the ion exchanger 103. The second cooling water circuit 123 is provided with a buffer tank 109, and the conductivity of the cooling water stored in the buffer tank 109 gradually decreases.

  Influence of exhaust heat of the fuel cell 20 by lowering the ion concentration of the cooling water by circulating the cooling water in a second cooling water circuit 123 different from the first cooling water circuit 121 for cooling the fuel cell 20 Without receiving the cooling water, the cooling water having a low conductivity at a low temperature can be accumulated in the second cooling water circuit 123 including the buffer tank 109. At this time, since the heat exchanger 115 is provided in the second cooling water circuit 123, the effect of suppressing the thermal deterioration of the ion exchanger 103 can be further enhanced.

  The output of the second pump 107 may be a constant value or a variable value. For example, the second pump driver 94 may change the output of the second pump 107 based on the second conductivity. In this case, the second pump driving section 94 may increase the output of the second pump 107 as the second conductivity is higher. Thereby, the conductivity of the cooling water circulating in the second cooling water circuit 123 can be quickly reduced.

  On the other hand, when the second conductivity is low and it is not necessary to perform cooling water ion removal (S31 / No), the determination unit 92 controls the second pump driving unit 94 to drive the second pump 107. Is stopped (step S27).

  In accordance with the instruction from the determination unit 92, the second pump driving unit 94 stops the second pump 107. Thereby, the state in which the cooling water with low conductivity is held in the second cooling water circuit 123 including the buffer tank 109 is maintained without performing the ion removal of the cooling water by the ion exchanger 103. Therefore, the life of the ion exchanger 103 can be extended without unnecessarily lowering the conductivity of the cooling water.

  On the other hand, in the above step S23, when it is necessary to connect the first cooling water circuit 121 and the second cooling water circuit 123 (S23 / Yes), the determination unit 92 drives the first flow path switching valve. It instructs the section 95 and the second flow path switching valve driving section 96 to set the first flow path switching valve 111 and the second flow path switching valve 113 to the connection mode, respectively (step S25).

  In accordance with the instruction from the determination unit 92, the first flow path switching valve driving unit 95 and the second flow path switching valve driving unit 96 are connected to the first flow path switching valve 111 and the second flow path switching valve 113, respectively. The first flow path switching valve 111 and the second flow path switching valve 113 are driven so as to be in the connection mode. Thereby, the first cooling water circuit 121 and the second cooling water circuit 123 are connected to form a third cooling water circuit 131.

  In a state where the third cooling water circuit 131 is formed, the determination unit 92 instructs the second pump driving unit 94 to hold the second pump 107 in a stopped state (Step S27). In accordance with the instruction from the determination unit 92, the second pump driving unit 94 stops driving the second pump 107.

  In this state, the high-conductivity cooling water circulating in the first cooling water circuit 121 flows into the second cooling water circuit 123 and is accumulated in the buffer tank 109 having a relatively large capacity. On the other hand, the first cooling water circuit 121 is supplied with the cooling water having low conductivity held in the second cooling water circuit 123 including the buffer tank 109. In this way, the cooling water whose conductivity has increased due to the cooling of the fuel cell 20 can be replaced with cooling water having a low conductivity, and electrical insulation of the cooling water can be ensured.

  Further, since the cooling water stored in the buffer tank 109 is at a lower temperature than the cooling water circulating in the first cooling water circuit 121, the low-temperature cooling water is supplied to the fuel cell 20. Thus, the fuel cell 20 can be cooled quickly.

  After stopping the second pump 107 in step S27 or driving the second pump 107 in step S33, the determination unit 92 returns to step S21 and repeats the processing of FIG. 6 described so far. Execute.

<5. Modification>
So far, the fuel cell system 100 according to the present embodiment has been described, but the fuel cell system 100 according to the present embodiment can be variously modified. Hereinafter, some of the modifications will be described.

(5-1. First Modification)
7 and 8 are schematic diagrams illustrating a fuel cell system 200 according to a first modification. In the fuel cell system 200 according to the first modification, the first flow path switching valve 211 is provided at a connection portion between the second cooling water circuit 123 and the second connection passage 127. Further, a second flow path switching valve 213 is provided at a connection portion between the second cooling water circuit 123 and the first connection passage 125.

  The first pump 105 and the fuel cell 20 are connected to the first cooling water circuit 121 on the downstream side of the connection portion between the first cooling water circuit 121 and the first connection passage 125 and in the first cooling water circuit. It is arranged in a portion 121a on the upstream side of a connection portion between the first connection passage 121 and the second connection passage 127. The first pump 105 may be arranged downstream of the fuel cell 20. The radiator 101 is arranged at a position other than the portion 121a in the first cooling water circuit 121.

  The ion exchanger 103 is disposed in a portion 123 a of the second cooling water circuit 123 downstream of the first flow path switching valve 211 and upstream of the second flow path switching valve 213. . The second pump 107, the buffer tank 109, and the heat exchanger 115 are arranged at positions other than the portion 123a in the second cooling water circuit 123. The arrangement positions of the second pump 107, the buffer tank 109, and the heat exchanger 115 may be appropriately changed.

  The first flow path switching valve 211 has a circulation mode in which the second connection passage 127 is closed while the portion 123a of the second cooling water circuit 123 is opened, and a second passage passage 127 in which the second connection passage 127 is opened. The connection mode in which the portion 123a of the second cooling water circuit 123 is closed can be switched. Further, the second flow path switching valve 213 has a circulation mode in which the first connection passage 125 is closed while the portion 123a of the second cooling water circuit 123 is opened, and a circulation mode in which the first connection passage 125 is opened. Thus, the connection mode in which the portion 123a of the second cooling water circuit 123 is closed can be switched.

  As shown in FIG. 7, when both the first flow path switching valve 211 and the second flow path switching valve 213 are set to the circulation mode, the two first cooling water circuits 121 and the second Is formed. In this case, the fuel cell 20 is cooled by circulating the cooling water through the first cooling water circuit 121. Further, as the cooling water circulates through the second cooling water circuit 123, the ion concentration of the cooling water decreases, and the cooling water having low conductivity is accumulated in the buffer tank 109.

  As shown in FIG. 8, when both the first flow path switching valve 211 and the second flow path switching valve 213 are set to the connection mode, the first cooling water circuit 121 connects to the first connection passage 125, A third cooling water circuit 231 that returns to the first cooling water circuit 121 again via the second cooling water circuit 123 and the second connection passage 127 is formed. In the third cooling water circuit 231, the cooling water pumped by the second pump 107 can be circulated without passing through the ion exchanger 103.

  Further, in the fuel cell system 200 according to the first modified example, even when the third cooling water circuit 231 is formed, the cooling water pumped by the first pump 105 is used as the first cooling water. The circuit 121 can be circulated. The cooling water pumped by the first pump 105 and the cooling water pumped by the second pump 107 join at a connection portion between the first cooling water circuit 121 and the second connection passage 127 to form the first cooling water circuit 121. It flows through the cooling water circuit 121 and passes through the radiator 101.

  The cooling water that has passed through the radiator 101 is diverted at a connection portion between the first cooling water circuit 121 and the first connection passage 125, and a part of the cooling water flows through the portion 121 a of the first cooling water circuit 121. Then, some cooling water flows through the second cooling water circuit 123. Thereby, the low-conductivity and low-temperature cooling water held in the second cooling water circuit 123 including the buffer tank 109 is mixed with the cooling water circulating in the first cooling water circuit 121, The conductivity of the cooling water circulating through the cooling water circuit 121 can be reduced.

  Further, since the cooling water stored in the buffer tank 109 is at a lower temperature than the cooling water circulating in the first cooling water circuit 121, the low-temperature cooling water is supplied to the fuel cell 20. Thus, the fuel cell 20 can be cooled quickly.

  In the fuel cell system 200 according to the first modified example, the configuration other than the above-described point can be configured similarly to the fuel cell system 100 according to the above embodiment. Further, also in the fuel cell system 200 according to the first modified example, the switching control processing of the cooling water circuit can be executed according to the same flowchart as the switching control processing of the fuel cell system 100 according to the above embodiment.

  Also in the fuel cell system 200 according to the first modified example, similarly to the fuel cell system 100 according to the above-described embodiment, a short-term decrease in the ion removing ability of the ion exchanger 103 and thermal deterioration are suppressed, The life of the ion exchanger 103 can be extended. When the conductivity of the cooling water circulating in the first cooling water circuit 121 for cooling the fuel cell 20 increases, the conductivity is reduced by the cooling water accumulated in the buffer tank 109 to reduce the electric conductivity of the cooling water. Insulation can be ensured, and the temperature of the cooling water can be reduced.

(5-2. Second Modification)
9 and 10 are schematic diagrams showing a fuel cell system 250 according to a second modification. In the fuel cell system 250 according to the second modified example, the arrangement position of the first pump 105 and the direction of circulation of the cooling water in the second cooling water circuit 123 by the second pump 107 are changed to the first modified example. This is different from the fuel cell system 250.

  In the fuel cell system 250 according to the second modification, the first pump 105 is located upstream of a connection portion between the first cooling water circuit 121 and the second connection passage 127 in the first cooling water circuit 121. The first cooling water circuit 121 and the first connection passage 125 are disposed at positions other than the portion 121 a downstream of the connection portion between the first cooling water circuit 121 and the first connection passage 125. Further, the direction of circulation of the cooling water circulated through the second cooling water circuit 123 by the second pump 107 is opposite to that in the case of the fuel cell system 200 according to the first modification.

  As shown in FIG. 9, when both the first flow path switching valve 211 and the second flow path switching valve 213 are set to the circulation mode, the two first cooling water circuits 121 and the second Is formed. In this case, the fuel cell 20 is cooled by circulating the cooling water through the first cooling water circuit 121. Further, as the cooling water circulates through the second cooling water circuit 123, the ion concentration of the cooling water decreases, and the cooling water having low conductivity is accumulated in the buffer tank 109.

  As shown in FIG. 10, when both the first flow path switching valve 211 and the second flow path switching valve 213 are set in the connection mode, the second cooling water circuit 121 is moved from the above-mentioned portion 121 a to the second cooling water circuit 121. A third cooling water circuit 251 is formed that returns to the above-mentioned portion 121a of the first cooling water circuit 121 again via the connection passage 127, the second cooling water circuit 123, and the first connection passage 125. In the third cooling water circuit 251, the cooling water pumped by the second pump 107 can be circulated without passing through the ion exchanger 103.

  Further, in the fuel cell system 250 according to the second modified example, even when the third cooling water circuit 251 is formed, the cooling water pumped by the first pump 105 is used as the first cooling water. The circuit 121 can be circulated. The cooling water pumped by the first pump 105 and the cooling water pumped by the second pump 107 merge at a connection portion between the first cooling water circuit 121 and the first connection passage 125 to form the first cooling water. The cooling water flows through the portion 121 a of the cooling water circuit 121 and passes through the fuel cell 20.

  The cooling water that has passed through the fuel cell 20 is diverted at a connection portion between the first cooling water circuit 121 and the second connection passage 127, and a part of the cooling water flows through the first cooling water circuit 121, Part of the cooling water flows through the second cooling water circuit 123. Thereby, the low-conductivity and low-temperature cooling water held in the second cooling water circuit 123 including the buffer tank 109 is mixed with the cooling water circulating in the first cooling water circuit 121, The conductivity of the cooling water circulating through the cooling water circuit 121 can be reduced.

  Further, since the cooling water stored in the buffer tank 109 is at a lower temperature than the cooling water circulating in the first cooling water circuit 121, the low-temperature cooling water is supplied to the fuel cell 20. Thus, the fuel cell 20 can be cooled quickly.

In the fuel cell system 250 according to the second modified example, the configuration other than the above-described point can be configured similarly to the fuel cell system 100 according to the above-described embodiment or the fuel cell system 200 according to the first modified example. . Further, also in the fuel cell system 250 according to the second modified example, the switching control processing of the cooling water circuit can be executed according to the same flowchart as the switching control processing of the fuel cell system 100 according to the above embodiment.
Can be done.

  Also in the fuel cell system 250 according to the second modified example, similarly to the fuel cell system 100 according to the above-described embodiment, a short-term decrease in the ion removal ability of the ion exchanger 103 and thermal deterioration are suppressed, The life of the ion exchanger 103 can be extended. When the conductivity of the cooling water circulating in the first cooling water circuit 121 for cooling the fuel cell 20 increases, the conductivity is reduced by the cooling water accumulated in the buffer tank 109 to reduce the electric conductivity of the cooling water. Insulation can be ensured, and the temperature of the cooling water can be reduced.

(5-3. Third Modification)
FIG. 11 is a schematic diagram showing a fuel cell system 300 according to the third modification. In the fuel cell system 300 according to the third modification, the buffer tank 109 provided in the second cooling water circuit 123 in the fuel cell system 100 according to the above embodiment is replaced with a cooling circuit 310 for the secondary battery 30. Things. The cooling circuit 310 of the secondary battery 30 mounted on the fuel cell vehicle 1 is connected in the middle of the second cooling water circuit 123.

  The second cooling water circuit 123 includes a third flow path switching valve 112 that switches whether to circulate the cooling water to the cooling circuit 310 of the secondary battery 20. The third flow path switching valve 112 allows the cooling water to circulate through the cooling circuit 310 by opening the cooling circuit 310 side and closing the bypass path 129 side. On the other hand, the third flow path switching valve 112 closes the cooling circuit 310 side and opens the bypass path 129 side, thereby preventing the cooling water from circulating through the cooling circuit 310.

  Since the capacity of the cooling circuit 310 of the secondary battery 30 is larger than the capacity of the cooling water circulating in the cooling circuit of the fuel cell 20, the capacity of the cooling water circulating in the cooling circuit 310 is larger than the capacity of the first cooling water circuit 121. Satisfies the amount of water required to lower the conductivity of the circulating cooling water. For this reason, the cooling circuit 310 of the secondary battery 30 functions similarly to the buffer tank that stores the cooling water. In the fuel cell system 300 according to the third modification, a buffer tank is not required, and the fuel cell system 300 is more practical as the fuel cell system 300 mounted on the fuel cell vehicle 1.

  When making the secondary battery 30 function as a buffer tank, the heat exchanger 115 lowers the temperature of the cooling water flowing through the second cooling water circuit 123 to the cooling temperature of the secondary battery 30 (for example, 25 ° C.) or lower. I just want to be able.

  Although FIG. 11 shows the fuel cell system 100 according to the above embodiment in which the buffer tank 109 is replaced with a cooling circuit 310 for the secondary battery 30, the fuel cell system 200 or the second embodiment The buffer tank 109 of the fuel cell system 250 according to the modified example may be replaced with the cooling circuit 310 of the secondary battery 30.

  As described above, in the fuel cell system according to the present embodiment, the cooling water ion is removed in the second cooling water circuit 123 different from the first cooling water circuit 121 for cooling the fuel cell 20. Thereby, unnecessary ion removal is suppressed, and the life of the ion exchanger 103 can be extended.

  Since the second cooling water circuit 123 has no heat generating element, when the cooling water is circulated through the second cooling water circuit 123 to remove ions of the cooling water, thermal deterioration of the ion exchanger 103 is suppressed. be able to. Further, in the fuel cell system according to the present embodiment, since the heat exchanger 115 is provided in the second cooling water circuit 123, the temperature rise of the cooling water circulating in the second cooling water circuit 123 is suppressed. In addition, the effect of suppressing the thermal deterioration of the ion exchanger 103 can be enhanced.

  The cooling water whose ions have been removed by the second cooling water circuit 123 and whose conductivity has been reduced is accumulated in the buffer tank 109 in a low temperature state, so that the first cooling water circuit 121 and the second cooling water When connecting the circuit 123 and introducing the low-conductivity cooling water into the first cooling water circuit 121, low-temperature cooling water can be supplied to the fuel cell 20.

  As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. It is apparent that those skilled in the art to which the present invention pertains can conceive various changes or modifications within the scope of the technical idea described in the claims. It is understood that these also belong to the technical scope of the present invention.

  For example, in the above embodiment, the heat exchanger 115 is provided in the second cooling water circuit 123, but the present invention is not limited to this example. The heat exchanger 115 may be replaced by a heat radiator. Alternatively, the heat exchanger 115 or the heat radiating device may be omitted.

  In the above embodiment, the first cooling water circuit 121 and the second cooling water circuit 123 are connected based on the conductivity of the cooling water circulating in the first cooling water circuit 121 or the temperature in the fuel cell 20. However, the present invention is not limited to such an example. For example, the first cooling water circuit 121 and the second cooling water circuit 123 are based on the relationship between the accumulated time for circulating the cooling water through the first cooling water circuit 121 and the amount of increase in the conductivity of the cooling water in advance. May be set in advance, and the first cooling water circuit 121 and the second cooling water circuit 123 may be connected when the time has elapsed. In this case, the first conductivity detector 117 can be omitted.

  In the above embodiment, whether or not to circulate the cooling water in the second cooling water circuit 123 is determined based on the conductivity of the cooling water circulating in the second cooling water circuit 123. It is not limited to such an example. For example, after terminating the connection between the first cooling water circuit 121 and the second cooling water circuit 123, the second pump 107 is driven for a predetermined period of time to supply the second cooling water circuit 123 with the cooling water. May be circulated to remove ions of the cooling water. In this case, the second conductivity detector 119 can be omitted.

  Further, in the above embodiment, the fuel cell system mounted on the fuel cell vehicle has been described as an example, but the present invention is not limited to such an example. The present invention can be applied to a case where the fuel cell system is mounted on a vehicle other than the fuel cell vehicle 1.

1 fuel cell vehicles (fuel cell range extender vehicles)
Reference Signs List 20 fuel cell 30 secondary battery 90 control device 100 fuel cell system 101 radiator 103 ion exchanger 105 first pump 107 second pump 109 buffer tank 111 first flow switching valve 113 second flow switching valve 115 Heat exchanger 117 First conductivity detector 119 Second conductivity detector 121 First cooling water circuit 123 Second cooling water circuit 125 First connection passage 127 Second connection passage

Claims (10)

A fuel cell,
A first cooling water circuit formed so that cooling water passing through the fuel cell can circulate;
A second cooling water circuit comprising an ion exchanger and formed so that cooling water can circulate;
A flow path switching valve that switches connection and disconnection between the first cooling water circuit and the second cooling water circuit;
A fuel cell system comprising: When connecting the first cooling water circuit and the second cooling water circuit, a third cooling water circuit is formed by a part of the first cooling water circuit and a part of the second cooling water circuit. Is composed,
2. The fuel cell system according to claim 1, wherein the ion exchanger is provided in a portion of the second cooling water circuit that does not constitute the third cooling water circuit. 3.   The fuel cell system according to claim 1, wherein the second cooling water circuit includes a buffer tank that stores cooling water.   The fuel cell system according to any one of claims 1 to 3, wherein the second cooling water circuit includes a cooler that cools cooling water.   5. The circuit according to claim 1, wherein at least one of the first cooling water circuit and the second cooling water circuit includes a conductivity detector that detects a conductivity of cooling water. 6. The fuel cell system as described. A control device for controlling the operation of the flow path switching valve,
The control device is configured such that, in a state where the first cooling water circuit and the second cooling water circuit are shut off, the conductivity of the cooling water flowing through the first cooling water circuit exceeds a first threshold value. The fuel cell system according to claim 5, wherein the first cooling water circuit and the second cooling water circuit are connected when the first cooling water circuit is turned on.   The fuel cell according to claim 6, wherein the control device circulates the cooling water through the second cooling water circuit in a state where the first cooling water circuit and the second cooling water circuit are shut off. system.   The control device stops the circulation of the cooling water in the second cooling water circuit when the conductivity of the cooling water circulating in the second cooling water circuit is less than a second threshold value. 3. The fuel cell system according to item 1.   The fuel cell system according to claim 1, wherein the fuel cell system is mounted on a fuel cell vehicle. The fuel cell system is mounted on a fuel cell vehicle, and the second cooling water circuit is connected to a cooling circuit of a secondary battery that is a power source of a drive motor of the fuel cell vehicle. 3. The fuel cell system according to 2.

Images