Fuel cell vehicles

Abstract

We will provide a fuel cell vehicle that can supply hot water on its own. [Solution] The fuel cell vehicle includes a cooling circuit having a radiator and a cooling water pump, which cools the fuel cell stack using cooling water, and a hot water supply circuit having a hot water supply pump and a hot water supply valve, which supplies hot water to the outside. The hot water supply circuit includes a heat exchanger that performs heat exchange between the cooling water discharged from the fuel cell stack and the water in the hot water supply circuit. An electric heater is provided in at least one of the cooling circuit and the hot water supply circuit. The electric heater is positioned in one or more of the following locations: a first position between the cooling water outlet of the fuel cell stack and the cooling water inlet of the heat exchanger, a second position between the hot water outlet of the heat exchanger and the hot water inlet of the hot water supply valve, and a third position inside a water storage tank provided in the hot water supply circuit.

Description

Technical Field

[0001] The present disclosure relates to a fuel cell vehicle capable of supplying hot water externally.

Background Art

[0002] Patent Document 1 describes a system that supplies power and hot water to the outside of a vehicle when the vehicle equipped with a fuel cell and a secondary battery is stopped.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the prior art, since the water heater is arranged outside the vehicle, there is a problem that hot water cannot be supplied by the vehicle alone.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, a fuel cell vehicle having a fuel cell system including a fuel cell stack is provided. This fuel cell vehicle has a radiator and a cooling water pump, a cooling circuit that cools the fuel cell stack using cooling water, a hot water supply pump and a hot water supply valve, and a hot water supply circuit that supplies hot water to the outside. The hot water supply circuit includes a heat exchanger that raises the temperature of the water by performing heat exchange between the cooling water discharged from the fuel cell stack and the water in the hot water supply circuit. An electric heater is arranged in at least one of the cooling circuit and the hot water supply circuit. The electric heater is arranged at one or more positions among a first position between the cooling water outlet of the fuel cell stack and the cooling water inlet of the heat exchanger, a second position between the hot water outlet of the heat exchanger and the hot water inlet of the hot water supply valve, and a third position inside a water storage tank provided in the hot water supply circuit. This fuel cell vehicle can provide hot water with high efficiency on its own. [Brief explanation of the drawing]

[0006] [Figure 1] This is an explanatory diagram showing the configuration of a fuel cell vehicle according to the first embodiment. [Figure 2] This is an explanatory diagram showing an example of the layout of a fuel cell system and hot water supply circuit inside a vehicle. [Figure 3] This is an explanatory diagram showing an example of the internal structure of a water storage tank. [Figure 4] This is an explanatory diagram showing another example of the internal structure of a water storage tank. [Figure 5] This is a flowchart showing the procedure for hot water supply in a fuel cell vehicle. [Figure 6] This is an explanatory diagram showing the state of the fuel cell vehicle in S16. [Figure 7] This is an explanatory diagram showing the state of the fuel cell vehicle in S20. [Figure 8] This is an explanatory diagram showing the heat generated during the warm-up operation of a fuel cell. [Figure 9] This is an explanatory diagram showing the configuration of a fuel cell vehicle according to the second embodiment. [Figure 10] This is an explanatory diagram showing the configuration of a fuel cell vehicle according to the third embodiment. [Modes for carrying out the invention]

[0007] Figure 1 is an explanatory diagram showing the configuration of a fuel cell vehicle 400 according to the first embodiment. The fuel cell vehicle 400 comprises a fuel cell system 100 and a hot water supply circuit 300. The fuel cell vehicle 400 is an electric vehicle driven by an electric motor. The electric motor for driving is driven using electricity generated by the fuel cell system 100. The fuel cell vehicle 400 is configured as a hot water supply system that uses the energy generated by the fuel cell system 100 to heat water in the hot water supply circuit 300 and supplies the generated hot water to the outside. Waste heat generated by the fuel cell system 100 is also used to heat the water. In other words, the fuel cell vehicle 400 is configured as an FC cogeneration hot water supply system that utilizes both the electricity generated by the fuel cell system 100 and the waste heat. The fuel cell vehicle 400 can be used, for example, as a mobile bathing vehicle for elderly care.

[0008] The fuel cell system 100 includes a fuel cell stack 110, an anode gas supply system 120, a cathode gas supply system 130, an FC system control unit 140, a power converter 150 including a secondary battery 152, an AC power supply unit 160, and a cooling circuit 200.

[0009] The anode gas supply system 120 supplies anode gas to the fuel cell stack 110. The cathode gas supply system 130 supplies cathode gas to the fuel cell stack 110. The anode gas is, for example, hydrogen. The cathode gas is, for example, air.

[0010] The FC system control unit 140 controls various parts of the fuel cell system 100. In Figure 1, some of the wiring connecting the FC system control unit 140 to the various parts of the fuel cell system 100 is omitted. The FC system control unit 140 is configured as an ECU (Electronic Control Unit) including a processor and memory.

[0011] The power converter 150 includes a secondary battery 152, as well as a DC / DC converter and inverter (not shown). The power converter 150 has the function of converting the DC power generated by the fuel cell stack 110 into AC power and supplying that AC power to the electric motor for driving the fuel cell vehicle 400. The power converter 150 also has the function of charging the secondary battery 152 using the DC power generated by the fuel cell stack 110. The secondary battery 152 is used to store the surplus power generated by the fuel cell stack 110 and the regenerative power of the drive motor.

[0012] The AC power supply unit 160 generates 100V AC power using the power supplied from the power converter 150. For example, the AC power supply unit 160 can be configured to generate 100V AC power from the DC power of the secondary battery 152. The 100V AC power can be used as a power source for the electrical equipment of the fuel cell vehicle 400. The 100V AC power can also be supplied to the outside of the fuel cell vehicle 400 via a power outlet provided in the fuel cell vehicle 400.

[0013] The cooling circuit 200 cools the fuel cell stack 110 using cooling water. The cooling circuit 200 includes a radiator 210, a cooling water pump 220, a water heater 230, an ion exchanger 240, and a shut-off valve 250.

[0014] The coolant outlet of the radiator 210 and the coolant inlet of the fuel cell stack 110 are connected by a supply pipe 201. The coolant outlet of the fuel cell stack 110 and the coolant inlet of the radiator 210 are connected by a discharge pipe 202.

[0015] A cooling water pump 220 is installed in the supply pipe 201. A water heater 230 is connected to the discharge pipe 202 via a three-way valve 232. The cooling water heated by the water heater 230 is returned to the discharge pipe 202 on the downstream side of the three-way valve 232. A bypass line 241 is provided between the discharge pipe 202 and the supply pipe 201. An ion exchanger 240 is installed in the bypass line 241. A rotary valve 242 is installed at the connection part between the discharge pipe 202 and the bypass line 241. The rotary valve 242 is used to adjust the amount of cooling water flowing through the bypass line 241.

[0016] A shut-off valve 250 is installed in the discharge pipe 202 at a position between the rotary valve 242 and the radiator 210. The shut-off valve 250 is used to stop the cooling water from flowing into the radiator 210. The shut-off valve 250 may be installed at a position on the outlet side of the radiator 210 in the supply pipe 201. A diverter valve 252 is installed at a position between the rotary valve 242 and the shut-off valve 250. The diverter valve 252 is used to supply part or all of the cooling water to the heat exchanger 330 of the hot water supply circuit 300.

[0017] The supply pipe 201 is provided with a temperature sensor for measuring the temperature Ti of the cooling water supplied to the fuel cell stack 110. The discharge pipe 202 is provided with a temperature sensor for measuring the temperature To of the cooling water discharged from the fuel cell stack 110.

[0018] In the normal state where hot water is not supplied externally, the shut-off valve 250 of the cooling circuit 200 is in the open state and the diverter valve 252 is in the closed state. In the normal state, the cooling water of the cooling circuit 200 circulates in the cooling circuit 200 via the radiator 210 without passing through the heat exchanger 330. In the hot water supply state where hot water is supplied externally, the shut-off valve 250 is switched to the closed state and the diverter valve 252 is switched to the open state. In the hot water supply state, the cooling water of the cooling circuit 200 circulates via the heat exchanger 330 without passing through the radiator 210.

[0019] The hot water supply circuit 300 includes a water storage tank 310, a hot water supply pump 320, a heat exchanger 330, an electric water heater 340, a hot water supply valve 350, a relief valve 360, a circulation valve 370, a water supply valve 380, and a hot water supply control unit 390.

[0020] The water outlet of the water storage tank 310 and the water inlet of the heat exchanger 330 are connected by an inlet pipe 301. The hot water outlet of the heat exchanger 330 and the hot water inlet of the hot water supply valve 350 are connected by a hot water supply pipe 302.

[0021] A hot water pump 320 is installed in the inlet piping 301, located between the water storage tank 310 and the heat exchanger 330. An electric water heater 340 is installed in the hot water piping 302, located between the heat exchanger 330 and the hot water valve 350. A mechanical relief valve 360 ​​is installed between the electric water heater 340 and the hot water valve 350. The relief valve 360 ​​has the function of opening when the internal pressure of the hot water piping 302 exceeds an opening threshold, returning water to the water storage tank 310. The relief valve 360 ​​prevents the hot water pump 320 from stopping due to an increase in the internal pressure of the hot water piping 302. The hot water pump 320 is configured to stop when the discharge pressure exceeds a specified pressure. The opening threshold of the relief valve 360 ​​is set to a value lower than the specified pressure of the hot water pump 320. The relief valve 360 ​​maintains the internal pressure of the hot water supply piping 302 below a specified pressure, preventing the hot water supply pump 320 from stopping.

[0022] Between the electric water heater 340 and the hot water valve 350, there is a circulation pipe 303 that returns water from the hot water pipe 302 to the water storage tank 310. A circulation valve 370 is installed in the circulation pipe 303. The circulation valve 370 is used to control whether or not water is returned from the hot water pipe 302 to the water storage tank 310. Water is supplied to the water storage tank 310 from the outside via a water supply valve 380. The hot water valve 350 and the water supply valve 380 may be automatic valves or manual valves.

[0023] A water heating heater 314 is installed inside the water storage tank 310. Two more water level sensors 311 and 312 are installed inside the water storage tank 310. The first water level sensor 311 detects whether the water level in the water storage tank 310 is below a predetermined lower limit. The second water level sensor 312 detects whether the water level in the water storage tank 310 is above a predetermined upper limit. The hot water supply control unit 390 controls the hot water supply pump 320 and the water supply valve 380 so that the water level in the water storage tank 310 is maintained between the lower limit and the upper limit. For example, the hot water supply control unit 390 stops the hot water supply pump 320 when the water level in the water storage tank 310 falls below the lower limit. Also, the hot water supply control unit 390 closes the water supply valve 380 and stops the water supply to the water storage tank 310 when the water level in the water storage tank 310 reaches the upper limit.

[0024] The inlet pipe 301 is equipped with a temperature sensor to measure the temperature T1 of the water before it is heated by the heat exchanger 330. The hot water supply pipe 302 is equipped with a temperature sensor to measure the temperature T2 of the water after it has been heated by the heat exchanger 330. Downstream of the electric water heater 340, a temperature sensor is provided to measure the temperature T3 of the water supplied to the outside from the hot water valve 350. The water storage tank 310 is equipped with a temperature sensor to measure the temperature T4 of the water inside the water storage tank 310.

[0025] The hot water supply control unit 390 controls each part of the hot water supply circuit 300 according to the water temperature T1 to T4 within the hot water supply circuit 300. For example, if the water temperature T2 at the outlet side of the heat exchanger 330 is below the target temperature, the hot water supply control unit 390 keeps the circulation valve 370 open and the hot water supply valve 350 closed, thereby increasing the water temperature while circulating the water within the hot water supply circuit 300. When the water temperature T2 at the outlet side of the heat exchanger 330 reaches the target temperature, the hot water supply control unit 390 starts supplying hot water to the bathtub BT by closing the circulation valve 370 and opening the hot water supply valve 350.

[0026] The water heater 230, the electric water heater 340, and the water heater 314 are all electric heaters. The water heater 230 is installed in a first position between the cooling water outlet of the fuel cell stack 110 and the cooling water inlet of the heat exchanger 330. The electric water heater 340 is installed in a second position between the hot water outlet of the heat exchanger 330 and the hot water inlet of the hot water supply valve 350. The water heater 314 is located in a third position inside the water storage tank 310 provided in the hot water supply circuit 300. Some of these electric heaters may be omitted, and it is preferable to provide at least one electric heater. It is also particularly preferable that the hot water supply circuit 300 is configured to heat water using one or more electric heaters. These electric heaters heat water using the electricity generated by the fuel cell stack 110. That is, these electric heaters operate using the electricity supplied from the power converter 150.

[0027] In the normal state, when no hot water is supplied to the outside, the hot water valve 350 of the hot water supply circuit 300 is closed and the circulation valve 370 is open. Therefore, in the normal state, the water in the hot water supply circuit 300 circulates within the hot water supply circuit 300 via the water storage tank 310 and the heat exchanger 330 without being supplied to the outside. When hot water is supplied, the hot water valve 350 is switched to the open state and the circulation valve 370 is switched to the closed state.

[0028] The hot water control unit 390 has the function of controlling each part of the hot water supply circuit 300. In Figure 1, some of the wiring connecting the hot water control unit 390 and each part of the hot water supply circuit 300 is omitted. The hot water control unit 390 is configured as an ECU including a processor and memory. The hot water control unit 390 is configured to efficiently heat the water in the hot water supply circuit 300 by coordinating the operation of the fuel cell system 100 and the operation of the hot water supply circuit 300 in cooperation with the FC system control unit 140. The functions of the hot water control unit 390 and the FC system control unit 140 may be realized in a single ECU. A hot water switch 392 is connected to the hot water control unit 390. When the hot water switch 392 is pressed by the user, the operation to supply hot water from the hot water supply circuit 300 to the outside is started.

[0029] The hot water generated in the hot water supply circuit 300 is supplied to the outside via the hot water supply valve 350. In the example shown in Figure 1, the hot water is supplied to the bathtub BT and the shower head SW, respectively, via the mixing valve MX in the household HM. When the fuel cell vehicle 400 is used as a mobile bathing vehicle for elderly care, it is preferable that the bathtub BT be configured as a portable bathtub that can be mounted on the fuel cell vehicle 400.

[0030] By using the hot water supply circuit 300, the water can be heated in the heat exchanger 330 while circulating water within the hot water supply circuit 300 using the hot water supply pump 320. In addition, the water in the hot water supply circuit 300 can be heated using one or more electric heaters from among the water heating heater 230, electric water heater 340, and water heating heater 314, utilizing the electricity generated by the fuel cell stack 110.

[0031] Figure 2 is an explanatory diagram showing an example of the arrangement of the fuel cell system 100 and the hot water supply circuit 300 inside the vehicle. The fuel cell system 100, including the fuel cell stack 110, is housed in the engine compartment EC of the fuel cell vehicle 400. The hot water supply circuit 300, including the heat exchanger 330, is housed in the luggage compartment LR at the rear of the passenger compartment CB. The bathtub BT is also housed in the luggage compartment LR.

[0032] Conventional mobile bathing vehicles for elderly care have a kerosene boiler installed in the cargo area (LR), which has problems with the comfort of the passenger compartment (CB) due to vibration, odor, and heat. The fuel cell vehicle 400 of this embodiment does not have a kerosene boiler, and the quiet fuel cell system 100 is housed in the engine compartment (EC) which is isolated from the passenger compartment (CB), so a comfortable passenger compartment (CB) can be maintained.

[0033] In conventional fuel cell vehicles, when transporting hot water supply equipment, the heat generated in the fuel cell stack during operation is discharged into the atmosphere through the radiator, making it impossible to fully utilize the heat generated during operation. In the fuel cell vehicle 400 of this embodiment, the heat generated in the fuel cell stack 110 during operation can be transferred to the water in the hot water supply circuit 300 via the heat exchanger 330. Furthermore, the water can be heated using an electric heater even while the fuel cell vehicle 400 is in operation, using the power generated by the fuel cell stack 110. In addition, the hot water supply circuit 300 is configured to circulate the water back to the water storage tank 310 while raising its temperature, so the water can be heated efficiently using the heat from the electric heater. As a result, the fuel cell vehicle 400 can supply hot water to the outside with high efficiency and cleanliness.

[0034] To increase the amount of hot water supplied to the outside, it is possible to use the power generated by the fuel cell stack 110 to heat the water in the hot water supply circuit 300 using one or more electric heaters 230, 340, 314. In this case, it is possible that the power generation efficiency of the fuel cell stack 110 will deteriorate as the amount of power generated will increase, and the waste heat of the fuel cell stack 110 will increase. However, the waste heat of the fuel cell stack 110 is used by the heat exchanger 330 to heat the water in the hot water supply circuit 300. Therefore, the fuel cell vehicle 400 of this embodiment can realize a highly efficient FC cogeneration hot water supply system. Heating the water in the hot water supply circuit 300 can be performed while the fuel cell vehicle 400 is running, and can also be performed while it is stopped.

[0035] Figure 3 is an explanatory diagram showing an example of the internal configuration of the water storage tank 310. For ease of illustration, only the fuel cell stack 110, cooling water pump 220, heat exchanger 330, and hot water pump 320 are depicted in Figure 3, in addition to the water storage tank 310 and its associated flow paths. The water storage tank 310 has a casing 315 and partition plates 316 that divide the inside of the casing 315. The water storage tank 310 has a divided flow path structure in which the inside of the casing 315 is divided by multiple partition plates 316. The water path from the inlet 310in to the outlet 310out of the water storage tank 310 is bent in a zigzag pattern. The hot water heated in the heat exchanger 330 flows along the zigzag path of the water storage tank 310. The hot water flows smoothly from the inlet 310in to the outlet 310out without stagnating in the water storage tank 310, and then reaches the heat exchanger 330. Therefore, the heat exchange efficiency of water by the heat exchanger 330 can be increased.

[0036] Figure 4 is an explanatory diagram showing another example of the internal configuration of the water storage tank 310. In this example, a spiral partition plate 317 is provided inside the casing 315 of the water storage tank 310. The water path from the inlet 310in to the outlet 310out of the water storage tank 310 is spirally curved. The hot water heated in the heat exchanger 330 flows along the spiral path of the water storage tank 310. The hot water flows smoothly from the inlet 310in to the outlet 310out without stagnating in the water storage tank 310, and then reaches the heat exchanger 330. Therefore, the heat exchange efficiency of the water by the heat exchanger 330 can be increased.

[0037] In the fuel cell vehicle 400 shown in Figure 1, when the shut valve 250 of the cooling circuit 200 is closed and the flow diversion valve 252 is open, the cooling water discharged from the cooling water outlet of the fuel cell stack 110 returns to the cooling water inlet of the fuel cell stack 110 via the heat exchanger 330 without passing through the radiator 210. In this state, the thermal energy of the cooling water can be transferred to the water in the hot water supply circuit 300 without heat being lost in the radiator 210. On the other hand, the water in the water storage tank 310 is supplied to the heat exchanger 330 by the hot water supply pump 320, heated in the heat exchanger 330, and then heated as needed by the electric water heater 340 before returning to the water storage tank 310. As shown in Figures 3 or 4 above, the water storage tank 310 has a curved internal structure, which can increase the heat exchange efficiency of the heat exchanger 330.

[0038] Figure 5 is a flowchart showing the procedure for hot water supply in a fuel cell vehicle 400. It is preferable that the process in Figure 5 is performed periodically at regular intervals.

[0039] In S11, the hot water supply control unit 390 determines whether or not there is a hot water supply request from the user. Specifically, the hot water supply control unit 390 determines that there is a hot water supply request when the hot water supply switch 392 is pressed by the user and turns on. If there is no hot water supply request from the user, the process shown in Figure 5 ends. If there is a hot water supply request from the user, the process proceeds to S12.

[0040] In S12, the hot water supply control unit 390 determines whether the fuel cell vehicle 400 is in motion. Specifically, the hot water supply control unit 390 receives a signal from the fuel cell vehicle 400's driving control unit indicating whether the fuel cell vehicle 400 is in motion. If the fuel cell vehicle 400 is in motion, the process shown in Figure 5 ends. If the fuel cell vehicle 400 is stopped, the process proceeds to S13.

[0041] In S13, the hot water supply control unit 390 determines whether 100V AC power generated by the AC power supply device 160 is available. If 100V AC power is not available, the process shown in Figure 5 is terminated. If 100V AC power is available, the process proceeds to S14. In this embodiment, 100V AC power is used to operate the equipment in the hot water supply circuit 300. However, the equipment in the hot water supply circuit 300 may be operated using power supplied from the power converter 150. In this case, S13 is omitted.

[0042] In S14, the hot water supply control unit 390 starts the hot water supply pump 320. In S15, the FC system control unit 140 switches the flow path of the cooling circuit 200 to the heat exchanger 330 side. Specifically, the FC system control unit 140 switches the shut valve 250 of the cooling circuit 200 to the closed state and switches the flow diversion valve 252 to the open state. Preferably, the FC system control unit 140 further sets the opening degree of the rotary valve 242 to 100% so that the entire amount of cooling water passes through the heat exchanger 330 without passing through the bypass line 241. The three-way valve 232 is set, for example, so that the cooling water does not pass through the water heating heater 230. In S16, the FC system control unit 140 starts the cooling water pump 220.

[0043] Figure 6 is an explanatory diagram showing the state of the fuel cell vehicle 400 in S16. In this state, the shut valve 250 of the cooling circuit 200 is closed and the flow diversion valve 252 is open. As a result, the cooling water of the cooling circuit 200 circulates through a flow path via the heat exchanger 330, without passing through the radiator 210. The waste heat from the fuel cell stack 110 is supplied to the water in the hot water supply circuit 300 via the heat exchanger 330. The hot water supply valve 350 of the hot water supply circuit 300 is closed and the circulation valve 370 is open. As a result, the water in the hot water supply circuit 300 circulates through a circulation path including the circulation piping 303. This circulation path includes the water storage tank 310 and the heat exchanger 330, and is a flow path that circulates the water in the hot water supply circuit 300 while raising its temperature by utilizing the heat exchange in the heat exchanger 330. During the circulation of water within the hot water supply circuit 300, the water may be heated using either or both of the electric water heater 340 and the water heating element 314. The thick "X" drawn above the shut-off valve 250 and the hot water supply valve 350 indicates that these valves are closed. In addition, the dotted lines in the piping connected to these valves indicate that water does not flow through those sections.

[0044] The hot water supply control unit 390 is configured to circulate water in the circulation path of the hot water supply circuit 300, including the circulation piping 303, and raise the temperature of the hot water that can be supplied to the outside from the hot water supply valve 350 until the temperature reaches the target temperature, while raising the temperature of the water in the heat exchanger 330. The target temperature is set to a range of, for example, 45°C to 55°C.

[0045] In S17, the FC system control unit 140 starts power generation from the fuel cell stack 110. At this time, it is preferable that the fuel cell stack 110 operates in a warm-up state. "Warm-up" is an operation that raises the temperature of the fuel cell stack 110 by utilizing the self-heating caused by the power generation loss of the fuel cell stack 110. Warm-up allows the cooling water in the cooling circuit 200 to be heated efficiently, and it is possible to increase the amount of heat supplied from the cooling water in the cooling circuit 200 to the water in the hot water supply circuit 300 in the heat exchanger 330. As a result, it is possible to generate hot water while suppressing the power consumption of the electric heater.

[0046] Figure 8 is an explanatory diagram showing the heat generated during the warm-up operation of a fuel cell. In Figure 8, the horizontal axis represents the current density of the fuel cell, and the vertical axis represents the cell voltage per cell. The solid line graph PG_normal shows the characteristics of normal operation, and the dashed line graph PG_warm-up shows the characteristics of warm-up operation. Warm-up operation is an operation in which the fuel cell stack 110 is operated in a less efficient power generation state compared to normal operation. This less efficient power generation state is achieved, for example, by reducing the amount of air supplied to the fuel cell stack 110 compared to normal operation, thereby lowering the stoichiometric air-fuel ratio. In normal operation, the energy loss equivalent to the difference H1 between the theoretical cell voltage Eh and the cell voltage in normal operation becomes waste heat from the fuel cell stack 110. In warm-up operation, the energy loss equivalent to the difference H2 between the theoretical cell voltage Eh and the cell voltage in warm-up operation becomes waste heat from the fuel cell stack 110. In warm-up operation, the waste heat is extremely large compared to normal operation. Therefore, by performing a warm-up operation of the fuel cell stack 110, it is possible to raise the temperature of the water in the hot water supply circuit 300 while suppressing the power consumption of the electric heater.

[0047] In winter, by performing a warm-up operation, the water temperature in the hot water supply circuit 300 can be heated from 5°C to 50°C in approximately 15 minutes. When using the warm-up operation, the overall efficiency of the FC cogeneration hot water supply system in this embodiment is approximately 75%. On the other hand, the efficiency when heating water using only the power from normal operation without using the warm-up operation is 39%. When using the warm-up operation, the water can be heated with approximately twice the efficiency of normal operation, making it possible to start hot water supply in a shorter time.

[0048] In S18, the hot water supply control unit 390 determines whether the temperature of the hot water in the hot water supply circuit 300 is above a threshold. For example, the hot water supply control unit 390 determines whether a temperature selected from the temperature T3 of the hot water at the outlet side of the heat exchanger 330 and the temperature T4 of the hot water at the inlet side of the hot water supply valve 350 is above a preset threshold. This threshold corresponds to the target temperature of the hot water supplied to the outside. When the electric water heater 340 is not operating or when the electric water heater 340 is not installed, temperatures T3 and T4 are substantially the same. If the temperature of the hot water in the hot water supply circuit 300 is not above the threshold, the process returns from S18 to S17. If the temperature of the hot water in the hot water supply circuit 300 is above the threshold, the process proceeds to S19.

[0049] In S19, the FC system control unit 140 stops the power generation of the fuel cell stack 110. In S20, the hot water control unit 390 switches the flow path of the hot water circuit 300 to the hot water supply state. Specifically, the hot water control unit 390 switches the hot water valve 350 from the closed state to the open state and switches the circulation valve 370 from the open state to the closed state. If the hot water valve 350 and the circulation valve 370 are manual valves, S20 is performed by the user.

[0050] Figure 7 is an explanatory diagram showing the state of the fuel cell vehicle 400 in S20. In this state, the hot water supply valve 350 is open and the circulation valve 370 is closed. As a result, it is possible to supply hot water to the outside via the hot water supply valve 350.

[0051] In S21, the hot water control unit 390 determines whether the temperature of the hot water in the hot water circuit 300 is below a threshold. The same threshold used in S18 can be used for this purpose. If the temperature of the hot water in the hot water circuit 300 is below the threshold, the process returns to S17, and steps S17 to S20 are executed again. In this case, the hot water control unit 390 may maintain the valve of the hot water circuit 300 in the hot water supply state. If the temperature of the hot water in the hot water circuit 300 is above the threshold, the process proceeds to S22.

[0052] In S22, the hot water supply control unit 390 determines whether or not there are no more hot water requests from the user. Specifically, if the user switches the hot water supply switch 392 to the off state, the hot water supply control unit 390 determines that there are no more hot water requests. If there are still hot water requests from the user, the process returns to S21. If there are no more hot water requests from the user, the process proceeds to S23. In S23, the hot water supply control unit 390 stops the control related to hot water supply and terminates the process shown in Figure 5.

[0053] When heating the water in the hot water supply circuit 300 while the fuel cell stack 110 is generating power, a portion of the generated power is used to power auxiliary equipment of the fuel cell vehicle 400 other than the electric heaters 230, 340, and 314. Auxiliary equipment other than the electric heaters 230, 340, and 314 includes, for example, pumps and motors. Preferably, the remaining generated power is used to heat the water using one or more of the electric heaters 230, 340, and 314. This allows for efficient use of the power generated by the fuel cell stack 110 to produce hot water.

[0054] The shut-off valve 250 of the cooling circuit 200 may be replaced with a control valve such as a rotary valve. In this case, when the hot water is supplied, the FC system control unit 140 may set the opening of the control valve 250 and the opening of the flow diversion valve 252 to values ​​between 0% and 100%, respectively. That is, the flow path in the cooling circuit 200 may be set so that part or all of the cooling water circulates through the heat exchanger 330. For example, if the opening of the control valve 250 is set to a value greater than 0% and less than 100%, part of the cooling water in the cooling circuit 200 circulates through the heat exchanger 330, and the other part circulates through the radiator 210. As a result, the temperature of the fuel cell stack 110 is stabilized. Also, since the temperature of the cooling water at the cooling water outlet of the fuel cell stack 110 is higher, the temperature of the cooling water input to the heat exchanger 330 is higher.

[0055] In the processing procedure shown in Figure 5, hot water is generated while the fuel cell vehicle 400 is stopped, but it is also possible to generate hot water while the fuel cell vehicle 400 is running. In this case as well, the flow path in the cooling circuit 200 may be configured so that part or all of the cooling water circulates through the heat exchanger 330. For example, all of the cooling water may circulate through the heat exchanger 330 without passing through the radiator 210. In this state, while the fuel cell vehicle 400 is running, the water in the hot water supply circuit 300 can be heated by performing heat exchange between the cooling water and the water in the hot water supply circuit 300 using the heat exchanger 330. In this way, hot water can be generated while the fuel cell vehicle 400 is running by efficiently utilizing the waste heat from the fuel cell stack 110.

[0056] As described above, the fuel cell vehicle 400 of the first embodiment is configured as a clean FC cogeneration hot water supply system, making it possible to efficiently heat water and supply hot water to the outside.

[0057] Figure 9 is an explanatory diagram showing the configuration of the fuel cell vehicle 400 of the second embodiment. In the fuel cell vehicle 400 of the second embodiment, the shut valve 250 of the cooling circuit 200 in the first embodiment is omitted, and the cooling water of the cooling circuit 200 is configured to always pass through the heat exchanger 330. The second embodiment operates in substantially the same manner as the first embodiment. In the second embodiment, when heating the water in the hot water supply circuit 300, the cooling water discharged from the cooling water outlet of the fuel cell stack 110 returns to the cooling water inlet of the fuel cell stack 110 via the heat exchanger 330 and the radiator 210 in that order. As a result, the thermal energy of the cooling water can be transferred to the water in the hot water supply circuit 300 before heat is dissipated in the radiator 210.

[0058] In the first embodiment described above, as explained in Figures 6 and 7 above, the circulation path of the cooling circuit 200 can be configured so that the cooling water circulates via the heat exchanger 330 without passing through the radiator 210. Therefore, the first embodiment can transfer the waste heat from the fuel cell stack 110 to the water in the hot water supply circuit 300 more efficiently than the second embodiment.

[0059] Figure 10 is an explanatory diagram showing the configuration of the fuel cell vehicle 400 of the third embodiment. In the fuel cell vehicle 400 of the third embodiment, the water storage tank 310 of the first embodiment is omitted. In addition, elements related to the water storage tank 310 are omitted. Specifically, the relief valve 360, circulation valve 370, water supply valve 380 and their piping are omitted. Furthermore, the inlet side of the hot water supply pump 320 is directly connected to the bathtub BT via piping. With this configuration, it is possible to directly circulate and heat the water stored in the bathtub BT.

[0060] Other forms: This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. For example, this disclosure can also be implemented in the following forms (aspects). The technical features in the embodiments described above that correspond to the technical features in each of the forms described below can be replaced or combined as appropriate in order to solve some or all of the problems of this disclosure, or to achieve some or all of the effects of this disclosure. Furthermore, if such technical features are not described as essential in this specification, they can be deleted as appropriate.

[0061] (1) According to one embodiment of the present disclosure, a fuel cell vehicle is provided having a fuel cell system including a fuel cell stack. The fuel cell vehicle comprises a cooling circuit having a radiator and a cooling water pump for cooling the fuel cell stack with cooling water, and a hot water supply circuit having a hot water supply pump and a hot water supply valve for supplying hot water to the outside. The hot water supply circuit includes a heat exchanger for heating the water by performing heat exchange between the cooling water discharged from the fuel cell stack and the water in the hot water supply circuit. An electric heater is provided in at least one of the cooling circuit and the hot water supply circuit. The electric heater is located in one or more of the following positions: a first position between the cooling water outlet of the fuel cell stack and the cooling water inlet of the heat exchanger, a second position between the hot water outlet of the heat exchanger and the hot water inlet of the hot water supply valve, and a third position inside a water storage tank provided in the hot water supply circuit. This fuel cell vehicle can provide hot water with high efficiency on its own.

[0062] (2) In the fuel cell vehicle described above, the fuel cell system may be configured to raise the temperature of the cooling water by performing a warm-up operation that uses the self-heating due to the power generation loss of the fuel cell stack to raise the temperature of the fuel cell stack, thereby increasing the heat supplied from the cooling water to the water in the hot water supply circuit in the heat exchanger. This fuel cell vehicle makes it possible to raise the temperature of the water in the hot water supply circuit while reducing the power consumption of the electric heater.

[0063] (3) In the fuel cell vehicle described above, the hot water supply circuit may be configured to circulate the water in a circulation path within the hot water supply circuit and raise the temperature of the water in the heat exchanger until the temperature of the hot water that can be supplied to the outside from the hot water supply valve reaches a target temperature. This fuel cell vehicle makes it easy to adjust the temperature of the hot water inside the vehicle.

[0064] (4) In the fuel cell vehicle described above, a portion of the power generated by the fuel cell stack may be used to operate auxiliary equipment other than the electric heater, and the remaining power may be used for heating by the electric heater. This fuel cell vehicle can efficiently use the electricity generated by the fuel cell stack to produce hot water.

[0065] (5) In the fuel cell vehicle described above, the water may be heated up by performing a heat exchange between the cooling water and the water in the hot water supply circuit using the heat exchanger while the fuel cell vehicle is running. This fuel cell vehicle can generate hot water by utilizing the waste heat from the fuel cell stack while the vehicle is in motion.

[0066] This disclosure can also be implemented in various forms other than those described above. For example, it can be implemented in the form of a control method for a fuel cell vehicle, a computer program for implementing control of a fuel cell vehicle, or a non-transitory storage medium on which the computer program is recorded. [Explanation of symbols]

[0067] 100…Fuel cell system, 110…Fuel cell stack, 120…Anode gas supply system, 130…Cathode gas supply system, 140…FC system control unit, 150…Power converter, 152…Secondary battery, 160…AC power supply unit, 200…Cooling circuit, 201…Supply piping, 202…Discharge piping, 210…Radiator, 220…Cooling water pump, 230…Water heating heater (electric heater), 232…Three-way valve, 240…Ion exchanger, 241…Bypass line, 242…Rotary valve, 250…Shut-off valve, 252…Flow diversion valve, 300 ...Hot water supply circuit, 301...Inlet piping, 302...Hot water supply piping, 303...Circulation piping, 310...Water storage tank, 310in...Inlet, 310out...Outlet, 311...Water level sensor, 312...Water level sensor, 314...Water heating heater (electric heater), 315...Housing, 316...Partition plate, 317...Partition plate, 320...Hot water supply pump, 330...Heat exchanger, 340...Electric water heater (electric heater), 350...Hot water supply valve, 360...Relief valve, 370...Circulation valve, 380...Water supply valve, 390...Hot water supply control unit, 392...Hot water supply switch, 400...Fuel cell vehicle

Claims

1. A fuel cell vehicle having a fuel cell system including a fuel cell stack, A cooling circuit having a radiator and a cooling water pump, which cools the fuel cell stack using cooling water, A hot water supply circuit that has a hot water pump and a hot water valve and supplies hot water to the outside, Equipped with, The hot water supply circuit includes a heat exchanger that raises the temperature of the water by performing heat exchange between the cooling water discharged from the fuel cell stack and the water in the hot water supply circuit. An electric heater is provided in at least one of the cooling circuit and the hot water supply circuit. The aforementioned electric heater is A first position located between the cooling water outlet of the fuel cell stack and the cooling water inlet of the heat exchanger, A second position between the hot water outlet of the heat exchanger and the hot water inlet of the hot water supply valve, A third position inside the water storage tank provided in the hot water supply circuit, A fuel cell vehicle positioned at one or more of the following locations.

2. A fuel cell vehicle according to claim 1, A fuel cell vehicle comprising a fuel cell system configured to raise the temperature of the cooling water by performing a warm-up operation that utilizes the self-heating due to the power generation loss of the fuel cell stack to raise the temperature of the fuel cell stack, thereby increasing the heat supplied from the cooling water to the water in the hot water supply circuit in the heat exchanger.

3. A fuel cell vehicle according to claim 1 or 2, A fuel cell vehicle, wherein the hot water supply circuit is configured to circulate the water in a circulation path within the hot water supply circuit and raise the temperature of the hot water in the heat exchanger until the temperature of the hot water that can be supplied to the outside from the hot water supply valve reaches a target temperature.

4. A fuel cell vehicle according to claim 1, A fuel cell vehicle in which a portion of the power generated by the fuel cell stack is used to operate auxiliary equipment other than the electric heater, and the remaining power is used for heating by the electric heater.

5. A fuel cell vehicle according to claim 1, A fuel cell vehicle that, while the fuel cell vehicle is in motion, raises the temperature of the water by performing heat exchange between the cooling water and the water in the hot water supply circuit using the heat exchanger.

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