Fuel cell system

Abstract

Provided is a fuel cell system configured to be capable of, in a case in which there is no external power source, starting a fuel cell even if the ambient temperature is low.　A fuel cell system 1 comprises: a fuel cell 8 which is for generating power by reacting hydrogen and oxygen and which is capable of supplying power to a load 30; a hydrogen storage alloy tank 6 which is for storing hydrogen and which is capable of supplying hydrogen to the fuel cell 8; a heater 7 for warming the hydrogen storage alloy tank 6; a rechargeable battery 5 capable of supplying power to the heater 7; and a control circuit 4. The control circuit 4 executes first control processing for supplying power from the rechargeable battery 5 to the heater 7 if the hydrogen storage alloy tank 6 does not satisfy a prescribed condition of being capable of supplying hydrogen to the fuel cell 8. Accordingly, even in a case in which there is no external power source, the hydrogen storage alloy tank 6 is warmed by the heater 7 and hydrogen is supplied to the fuel cell 8, and the fuel cell 8 can be started.

Description

fuel cell system

[0001] The present invention relates to a fuel cell system.

[0002] Patent Document 1 discloses an AC uninterruptible power supply system using a fuel cell. In this AC uninterruptible power supply system, a battery supplies power to a load for a specified time after a commercial AC power outage occurs, and if power is not restored after that, the fuel cell is started up to supply power to the load. Hydrogen supplied to the fuel cell is stored in a hydrogen storage alloy.

[0003] Japanese Patent Application Laid-Open No. 2015-177576

[0004] In the AC uninterruptible power supply system disclosed in Patent Document 1, a heater that warms a hydrogen storage alloy tank is supplied with power from a commercial AC power source. In order to start the fuel cell, the temperature of the hydrogen storage alloy tank must be maintained above a specified value, and when the ambient temperature is low, such as in winter, the heater must be operated to maintain the temperature of the hydrogen storage alloy tank above the specified value. However, if there is no external power source, the heater cannot be operated, and the fuel cell cannot be started, which is a problem.

[0005] An object of the present invention is to provide a fuel cell system that can start up a fuel cell even when the environmental temperature is low, in the absence of an external power source.

[0006] A fuel cell system according to one aspect of the present invention includes a fuel cell capable of generating electricity by reacting hydrogen and oxygen and supplying the electricity to an electrical load, a hydrogen storage container capable of storing the hydrogen and supplying the hydrogen to the fuel cell, a heater for heating the hydrogen storage container, a power storage device capable of supplying the electricity to the heater, and a control unit, wherein the control unit executes a first control process to supply the electricity from the power storage device to the heater when the hydrogen storage container does not satisfy a predetermined condition for supplying the hydrogen to the fuel cell. Because the fuel cell system can supply electricity to the heater that heats the hydrogen storage container from the power storage device, the fuel cell system can heat the hydrogen storage container using the heater and supply hydrogen to the fuel cell, thereby enabling the fuel cell to start up, even in the absence of an external power source.

[0007] Fig. 1 is a block diagram showing an outline of the configuration of a fuel cell system 1 of a first embodiment. Fig. 2 is a block diagram of a control circuit 4. Fig. 3 is a flowchart showing power supply processing. Fig. 4 is a graph showing state transitions of the remaining capacity of a storage battery 5 and the hydrogen pressure in a hydrogen storage alloy tank 6. Fig. 5 is a graph showing state transitions of the power consumption of a load 30, the output of a fuel cell 8, and the output and remaining capacity of a storage battery 5. Fig. 6 is a block diagram of a fuel cell system 1 of a second embodiment. Fig. 7 is a block diagram of a fuel cell system 1 of a third embodiment.

[0008] A first embodiment of the present invention will be described. The drawings are used to explain technical features that can be adopted by the present invention. In other words, the configurations, controls, etc. shown in the drawings are merely illustrative examples and are not intended to limit the present invention.

[0009] <Configuration of Fuel Cell System 1> The configuration of the fuel cell system 1 of this embodiment will be described with reference to Figures 1 and 2. The fuel cell system 1 can start the fuel cell 8 and supply power to the load 30 even when the ambient temperature is low and there is no external power source, the grid power supply 20. Figure 1 shows the main configuration of the fuel cell system 1, and does not include switches, circuit switching devices, interface circuits, drive circuits, etc., as they are well known. An example of the load 30 is any electronic or electrical device that operates by receiving a power supply.

[0010] The fuel cell system 1 includes a hydrogen storage alloy tank 6 and a fuel cell 8 that generates electricity using hydrogen supplied from the hydrogen storage alloy tank 6. The hydrogen storage alloy tank 6 contains a hydrogen storage alloy that releases hydrogen through an endothermic reaction and stores the hydrogen. Therefore, the hydrogen storage alloy can achieve a much higher hydrogen filling density than gas. The supply temperature at which hydrogen can be released from the hydrogen storage alloy and supplied to the fuel cell 8 is designated X1. The hydrogen storage alloy tank 6 is equipped with a pressure sensor 2 that detects the pressure of hydrogen in the hydrogen storage alloy tank 6 and a heater 7 that heats the hydrogen storage alloy tank 6. The fuel cell system 1 also includes a control circuit 4, a temperature sensor 3, the pressure sensor 2, a power detector 12, a storage battery 5, an AC-DC converter 10, a DC-AC inverter 11, a DC-DC converter 9, a display 26, a speaker 27, and an operation panel 28. The operation panel 28 is equipped with a load power supply switch 29 and input buttons (not shown).

[0011] The control circuit 4 controls the fuel cell system 1. Specifically, the control circuit 4 controls the fuel cell 8, the storage battery 5, the heater 7, the display 26, and the speaker 27. As shown in FIG. 2 , the control circuit 4 includes a CPU 41, a RAM 42, a ROM 43, a non-volatile memory 44, an input / output interface 45, and auxiliary circuits (not shown). The CPU 41 executes programs for the power supply process described below. The RAM 42 temporarily stores data required for executing various processes. The ROM 43 stores various programs. The non-volatile memory 44 stores various setting values ​​required for executing the programs. The input / output interface 45 mediates the input and output of signals between the CPU 41 and the temperature sensor 3, the pressure sensor 2, the heater 7, the power detector 12, the storage battery 5, and the fuel cell 8. The control circuit 4 may be configured as a dedicated circuit board for executing the power supply process described below. Alternatively, the control circuit 4 may be configured as a dedicated ASIC.

[0012] The operation panel 28 receives input from the user and outputs it to the CPU 41 of the control circuit 4. When the user turns on the load power supply switch 29, a signal is output to the CPU 41 of the control circuit 4. Furthermore, when the user operates the operation panel 28 to input the rated capacity of power consumption of the load 30, the operation panel 28 outputs the input value of the rated capacity of power consumption of the load 30 to the CPU 41 of the control circuit 4. The CPU 41 stores the received value of the rated capacity of power consumption of the load 30 in the non-volatile memory 44.

[0013] The AC-DC converter 10 converts the AC voltage of the system power supply 20 into DC voltage and outputs it to a power supply line 22. An example of the system power supply 20 is a commercial power supply, e.g., 100 V AC. An example of the output voltage of the AC-DC converter 10 is 48 V DC. The AC-DC converter 10 can supply power to the storage battery 5 to charge it. Charging the storage battery 5 from the system power supply 20 via the AC-DC converter 10 is performed when the remaining charge of the storage battery 5 becomes so low that it is no longer possible to start the fuel cell 8. In this case, the storage battery 5 can be charged to start the fuel cell 8. Therefore, even if the remaining charge of the storage battery 5 becomes so low that the fuel cell 8 cannot start generating electricity, the storage battery 5 can be charged via the system power supply 20, which is an external power source. If a function for charging the storage battery 5 from the system power supply 20 is not provided, the AC-DC converter 10 need not be provided.

[0014] The pressure sensor 2 is provided in the hydrogen storage alloy tank 6, detects the pressure of hydrogen in the hydrogen storage alloy tank 6, and outputs the detected value to the control circuit 4. The heater 7 heats the hydrogen storage alloy tank 6 under the control of the control circuit 4, heating the hydrogen storage alloy to a constant temperature. The power detector 12 detects the power supplied to the load 30 from the power supply line 21, and outputs the detected result to the control circuit 4. The control circuit 4 can obtain the power consumption of the load 30 from the output of the power detector 12. The temperature sensor 3 is provided in the housing of the fuel cell system 1, measures the ambient temperature, and outputs the measured result to the control circuit 4. The temperature sensor 3 may be provided outside the housing of the fuel cell system 1.

[0015] The storage battery 5 is charged with power supplied from the fuel cell 8 via power feeders 25 and 22. An example of the output voltage of the storage battery 5 is 48 V DC. The storage battery 5 is controlled by the control circuit 4. The storage battery 5 supplies power to the DC / AC inverter 11 via power feeders 24 and 22. The DC / AC inverter 11 converts the DC voltage to an AC voltage and supplies the power to the load 30. An example of the output voltage of the DC / AC inverter 11 is 100 V AC. The storage battery 5 also supplies power to the heater 7 via power feeders 24, 22, and 25. The storage battery 5 also supplies power to the control circuit 4 via power feeders 24, 22, and 23. Power feeders 23 to 25 are connected to power feeder 22.

[0016] The fuel cell 8 reacts oxygen with hydrogen supplied from the hydrogen storage alloy tank 6 to generate DC voltage electricity, which is supplied to the DCDC converter 9. The DCDC converter 9 converts the DC voltage supplied from the fuel cell 8 to, for example, 48 V. The DCAC inverter 11 converts the DC voltage supplied from the fuel cell 8 via the DCDC converter 9 into AC voltage. For example, the DCAC inverter 11 converts 48 V DC to 100 V AC.

[0017] The display 26 displays various displays required during operation of the fuel cell system 1 and warning displays (described later) under the control of the CPU 41. The speaker 27 emits warning sounds (described later) under the control of the CPU 41.

[0018] When the fuel cell system 1 of the first embodiment having the above-described configuration is not in use, the hydrogen storage alloy tank 6 containing the hydrogen storage alloy is not heated by the heater 7. When the system is used in a location without an external power source, the system is characterized in that the hydrogen storage alloy tank 6 is heated by supplying power from the storage battery 5 to the heater 7.

[0019] <Power Supply Process> The power supply process of the fuel cell system 1 of the first embodiment will be described with reference to Figure 3. When the load power supply switch 29 on the operation panel 28 of the fuel cell system 1 is turned ON (S1: YES), the CPU 41 of the control circuit 4 is started up and reads and executes a power supply process program from the ROM 43. The CPU 41 supplies power from the storage battery 5 to the load 30 (S2). Therefore, the load 30 can operate even in places without an external power source. Furthermore, power can be supplied to the load 30 immediately upon startup of the fuel cell system 1. Next, the CPU 41 determines whether the load power supply switch 29 is turned OFF (S3). If the CPU 41 determines that the load power supply switch 29 is turned OFF (S3: YES), it stops the supply of power from the storage battery 5 to the load 30 (S16).

[0020] If the CPU 41 does not determine that the load power supply switch 29 has been turned OFF (S3: NO), it determines whether the fuel cell 8 is likely to be able to complete preparations for power generation (S4). As an example, the CPU 41 determines whether the fuel cell 8 is likely to complete preparations for power generation based on the current power consumption of the load 30 detected by the power detector 12, the remaining charge of the storage battery 5, and the hydrogen pressure value in the hydrogen storage alloy tank 6 detected by the pressure sensor 2 (S4). The remaining charge of the storage battery 5 is estimated by the CPU 41 from the voltage input from the storage battery 5. For the fuel cell 8 to complete preparations for power generation, the remaining charge of the storage battery 5 must be sufficient to allow the heater 7 to heat the hydrogen storage alloy tank 6 with the power from the storage battery 5 until the fuel cell 8 meets the hydrogen supply condition.

[0021] If the CPU 41 does not determine that the fuel cell 8 is likely to be able to complete preparation for power generation (S4: NO), it stops the heater 7 (S5). The CPU 41 proceeds to S2. If the CPU 41 determines that the fuel cell 8 is likely to be able to complete preparation for power generation (S4: YES), it determines whether the hydrogen storage alloy tank 6 satisfies a predetermined condition for supplying hydrogen (S6). An example of the predetermined condition may be whether the hydrogen pressure in the hydrogen storage alloy tank 6 is P1 or higher. Another example of the predetermined condition is whether the temperature of the hydrogen storage alloy tank 6 is X1 or higher. If the CPU 41 does not determine that the hydrogen pressure in the hydrogen storage alloy tank 6 is A1 or higher (S6: NO), it uses the heater 7 with power from the storage battery 5 to heat the hydrogen storage alloy tank 6 (S7). If the CPU 41 does not determine that the temperature of the hydrogen storage alloy tank 6 is X1 or higher (S6: NO), it may also use the heater 7 with power from the storage battery 5 to heat the hydrogen storage alloy tank 6 (S7). Therefore, if power cannot be supplied to the heater 7 until predetermined conditions for the storage battery 5 to supply hydrogen to the fuel cell 8 are met, power can be used effectively by prioritizing power supply to the load 30. Furthermore, since the storage battery 5 can supply power to the heater 7 which heats the hydrogen storage alloy tank 6, even in the absence of an external power source, the heater 7 can heat the hydrogen storage alloy tank 6 and supply hydrogen to the fuel cell 8, thereby enabling the fuel cell 8 to start up. After processing S7, the CPU 41 advances the process to S2.

[0022] If the CPU 41 determines that the hydrogen storage alloy tank 6 satisfies the predetermined conditions for supplying hydrogen (S6: YES), it stops the heater 7, starts power generation by the fuel cell 8, and supplies power from the fuel cell 8 to the load 30 (S8). The CPU 41 stops the supply of power from the storage battery 5 to the load 30. Next, the CPU 41 determines whether the load power supply switch 29 has been turned OFF (S9). If the CPU 41 determines that the load power supply switch 29 has been turned OFF (S9: YES), it stops power generation by the fuel cell 8 (S15) and stops the supply of power to the load 30 (S16). If the CPU 41 does not determine that the load power supply switch 29 has been turned OFF (S9: NO), it determines whether the power consumption of the load 30 exceeds the rated output of the fuel cell 8 (S10). The rated output of the fuel cell 8 is pre-stored in the non-volatile memory 44. In the determination of S10, the CPU 41 reads the rated output of the fuel cell 8 from the non-volatile memory 44 and compares the power consumption of the load 30 detected by the power detector 12 with the rated output. If the CPU 41 determines that the power consumption of the load 30 exceeds the rated output of the fuel cell 8 (S10: YES), the fuel cell 8 and the storage battery 5 supply power to the load 30 (S12). Therefore, power is supplied to the load 30 from the fuel cell 8 and the storage battery 5, so that power higher than the rated output of the fuel cell 8 can be supplied to the load 30. If the CPU 41 does not determine that the power consumption of the load 30 exceeds the rated output of the fuel cell 8 (S10: NO), the CPU 41 charges the storage battery 5 while supplying power from the fuel cell 8 to the load 30 (S11). Therefore, the fuel cell system 1 does not require an external power source to charge the storage battery 5.

[0023] Next, the CPU 41 determines whether the power consumption of the load 30 exceeds the warning value (S13). If the power consumption of the load 30 detected by the power detector 12 exceeds the sum of the rated capacity of the fuel cell 8 and the remaining capacity of the storage battery 5, the CPU 41 determines that the power consumption of the load 30 exceeds the warning value. If the CPU 41 does not determine that the power consumption of the load 30 exceeds the warning value (S13: NO), the CPU 41 proceeds to S9. If the CPU 41 determines that the power consumption of the load 30 exceeds the warning value (S13: YES), the CPU 41 executes control to issue an overload warning (S14). The warning may be displayed on the display 26, or may be a warning sound or voice from the speaker 27, or both. An example of the warning displayed on the display 26 may be the display of an error number. In the case of displaying an error number, the error number indicates that an overload has occurred. Furthermore, text such as "Stopped due to overload" may be displayed on the display 26.

[0024] Next, the CPU 41 stops power generation by the fuel cell 8 (S15) and stops the supply of power from the fuel cell 8 and the storage battery 5 to the load 30 (S16). If the CPU 41 determines in the determination process of S13 that the power consumption of the load 30 exceeds the sum of the rated capacity of the fuel cell 8 and the remaining power of the storage battery 5 (S13: YES), it stops the power supply from the fuel cell 8 and the storage battery 5 to the load 30, thereby preventing a breakdown of the fuel cell system 1 due to an overload. Furthermore, in the event of an overload, the CPU 41 executes control to issue a warning before stopping the supply of power to the load 30 (S14), thereby notifying the user that the supply of power to the load 30 will be stopped.

[0025] Next, referring to the graphs shown in FIG. 4, the transitions in the remaining charge of the storage battery 5 and the hydrogen pressure in the hydrogen storage alloy tank 6 in the first embodiment will be described. In the graph of FIG. 4(1), the vertical axis represents the remaining charge of the storage battery 5, and the horizontal axis represents time. In the graph of FIG. 4(2), the vertical axis represents the hydrogen pressure in the hydrogen storage alloy tank 6, and the horizontal axis represents time. The storage battery 5 is fully charged until the load power supply switch 29 is turned ON. As an example, at time T1, the temperature of the hydrogen storage alloy tank 6 is lower than temperature X1, and the hydrogen storage alloy tank 6 does not satisfy the conditions for supplying hydrogen. Therefore, in order for the fuel cell 8 to generate power, it is necessary to prepare for power generation by heating the hydrogen storage alloy tank 6 to temperature X1 with the heater 7. When the load power supply switch 29 is turned ON at time T1, power is supplied from the storage battery 5 to the heater 7 to heat the hydrogen storage alloy tank 6. Therefore, the remaining charge of the storage battery 5 decreases, and the hydrogen pressure in the hydrogen storage alloy tank 6 increases. The period from time T1 to T2 is a period during which the hydrogen storage alloy tank 6 is heated until the hydrogen pressure in the hydrogen storage alloy tank 6 reaches a pressure sufficient to supply hydrogen to the fuel cell 8, during which the fuel cell 8 is preparing to generate electricity. When the hydrogen pressure in the hydrogen storage alloy tank 6 reaches a pressure sufficient to supply hydrogen to the fuel cell 8 (A1) at time T2, the supply of power from the storage battery 5 to the heater 7 is stopped. Since power is supplied from the fuel cell 8 to the storage battery 5 after time T2, the remaining battery charge of the storage battery 5 increases from time T2, and at time T3, the storage battery 5 is fully charged. Next, at time T4, when the user turns off the load power supply switch 29 on the operation panel 28, the fuel cell 8 stops generating electricity and is powered off. After time T4, the storage battery 5 remains fully charged. As the temperature of the hydrogen storage alloy tank 6 drops, the hydrogen pressure in the hydrogen storage alloy tank 6 decreases.

[0026] Next, with reference to the graphs shown in Fig. 5, the state transitions of the power consumption of the load 30, the output of the fuel cell 8, and the output and remaining capacity of the storage battery 5 in the first embodiment will be described. The graph in Fig. 5(1) is a graph where the vertical axis represents the power consumption of the load 30 and the horizontal axis represents time. The graph in Fig. 5(2) is a graph where the vertical axis represents the output of the fuel cell 8 and the horizontal axis represents time. The graph in Fig. 5(3) is a graph where the vertical axis represents the discharge amount and charge amount of the storage battery 5, with the upward direction representing the discharge amount of the storage battery 5 and the downward direction representing the charge amount of the storage battery 5, and the horizontal axis representing time. The graph in Fig. 5(4) is a graph where the vertical axis represents the remaining capacity of the storage battery 5 and the horizontal axis represents time.

[0027] An example of the power consumption of the load 30 is assumed to change as shown in FIG. 5(1). That is, the power consumption of the load 30 rises at time P1 and further increases at time P2. The power consumption of the load 30 reaches the same value as the rated output of the fuel cell 8 at time P3, and between times P4 and P5, it remains above the rated output of the fuel cell 8. The power consumption of the load 30 reaches the same value as the rated output of the fuel cell 8 at time P5, falls below the rated output of the fuel cell 8 at time P6, and then falls further below that value at time P8. At time P9, the load 30 stops, and the power consumption becomes zero. In contrast, as shown in FIG. 5(2), the fuel cell 8 starts generating power at time P1, reaches the rated output of the fuel cell 8 at time P3, and at time P6, the output of the fuel cell 8 decreases in accordance with the decrease in the power consumption of the load 30. Next, the output of the fuel cell 8 decreases in accordance with the decrease in the power consumption of the load 30 at time P8. At time P9, the power generation of the fuel cell 8 stops in accordance with the stop of the load 30. As shown in Figures 5 (3) and 5 (4), charging of the storage battery 5 begins at time P1 using the output from the fuel cell 8, and the remaining battery capacity increases. Charging stops at time P3 after time P2. Discharge begins at time P4, and the portion of the power consumed by the load 30 exceeds the rated output of the fuel cell 8. Therefore, the output of the shaded portion shown in Figure 5 (1) can be supplied by the output of the storage battery 5. At time P5, the power consumed by the load 30 becomes the same as the rated output of the fuel cell 8, so the storage battery 5 stops discharging. At time P6, the power consumed by the load 30 becomes lower than the rated output of the fuel cell 8, so the storage battery 5 is charged by the output of the fuel cell 8. At time P7, the storage battery 5 is fully charged, and charging stops.

[0028] Second Embodiment Next, a second embodiment will be described with reference to FIG. 6 . In the second embodiment, the configuration of the fuel cell system 1 differs from that of the first embodiment in that it includes a solar panel 40 and a DC-DC converter 13. The other configuration is the same as that of the first embodiment, so a description of the other configuration will be omitted. The output of the solar panel 40 is input to the DC-DC converter 13, converted to 48 V DC, and fed to the power feeder 25. Therefore, charging power for the storage battery 5 and power for the heater 7 can be supplied from sunlight. Therefore, the storage battery 5 can be charged even when the system power supply 20, which is an external power source, is not available.

[0029] Third Embodiment Next, a third embodiment will be described with reference to FIG. 7 . In the third embodiment, the configuration of the fuel cell system 1 differs from that of the first embodiment in that it includes a small wind power generator 50 and a DC-DC converter 13. The other configuration is the same as that of the first embodiment, so a description of the other configuration will be omitted. The output of the small wind power generator 50 is converted to 48 V DC by the DC-DC converter 13 and fed to the power feeder 25. Therefore, charging power for the storage battery 5 and power for the heater 7 can be supplied from the small wind power generator 50. Therefore, the storage battery 5 can be charged even when the system power supply 20, which is an external power source, is not available.

[0030] In the above embodiment, the hydrogen storage alloy tank 6 is an example of a "hydrogen storage container" of the present invention. The storage battery 5 is an example of a "power storage device" of the present invention. The control circuit 4 or the CPU 41 is an example of a "controller" of the present invention. The system power supply 20 is an example of an "external power supply" of the present invention. The load 30 is an example of an "electrical load" of the present invention. The solar panel 40 is an example of a "photovoltaic power generation device" of the present invention. The small wind power generator 50 is an example of a "wind power generation device" of the present invention. The processing of S6: NO and S7 is an example of a "first control process" of the present invention. The processing of S2 is an example of a "second control process" of the present invention. The processing of S11 is an example of a "third control process" of the present invention. The processing of S2, S4: NO, and S5 is an example of a "fourth control process" of the present invention. The processing of S12 is an example of a "fifth control process" of the present invention. The processing of S13: YES and S15 is an example of a "sixth control process" of the present invention.

[0031] The present invention is not limited to the above embodiment and various modifications are possible. A temperature sensor may be provided on the surface of or inside the hydrogen storage alloy tank 6 to detect the temperature of the hydrogen storage alloy tank 6 or the hydrogen storage alloy contained therein and output the temperature to the control circuit 4. Since the temperature of the hydrogen storage alloy is proportional to the hydrogen pressure in the hydrogen storage alloy tank 6, the CPU 41 may determine the temperature of the hydrogen storage alloy tank 6 based on the hydrogen pressure in the hydrogen storage alloy tank 6 detected by the pressure sensor 2. In this case, the temperature of the hydrogen storage alloy tank 6 can be determined from the hydrogen pressure in the hydrogen storage alloy tank 6 without using a temperature sensor. Note that the CPU 41 may determine whether the predetermined condition is met in the determination of S6 based on whether the temperature of the hydrogen storage alloy tank 6 is below the supply temperature (X1) at which hydrogen can be supplied to the fuel cell 8 or whether the hydrogen pressure in the hydrogen storage alloy tank 6 is below the supply pressure (A1) at which hydrogen can be supplied to the fuel cell 8. In this case, whether the hydrogen storage alloy tank 6 can supply hydrogen to the fuel cell 8 can be determined based on the temperature of the hydrogen storage alloy tank 6 or the pressure of hydrogen inside the hydrogen storage alloy tank 6. The value of the hydrogen pressure inside the hydrogen storage alloy tank 6 used in the determination of S6 may be determined based on the characteristics of the fuel cell 8. An all-solid-state battery or the like may be used for the storage battery 5. The device for issuing an overload warning is not limited to the display 26 and speaker 27, but may also be a light-emitting element such as an LED lamp or a device that emits a warning sound such as a buzzer.

[0032] 1: Fuel cell system 2: Pressure sensor 3: Temperature sensor 4: Control circuit 5: Storage battery 6: Hydrogen storage alloy tank 7: Heater 8: Fuel cell 12: Power detector 13: DCDC converter 20: System power supply 26: Display 27: Speaker 28: Operation panel 30: Load 40: Solar panel 41: CPU 50: Small wind power generator

Claims

1. A fuel cell system comprising: a fuel cell capable of generating electricity by reacting hydrogen and oxygen and supplying the electricity to an electrical load; a hydrogen storage container capable of storing the hydrogen and supplying the hydrogen to the fuel cell; a heater for heating the hydrogen storage container; a power storage device capable of supplying the electricity to the heater; and a control unit, wherein the control unit executes a first control process to supply the electricity from the power storage device to the heater if the hydrogen storage container does not satisfy predetermined conditions for being able to supply the hydrogen to the fuel cell.

2. The fuel cell system according to claim 1, characterized in that the control unit executes a second control process in which, when the power is being supplied from the power storage device to the heater, the power storage device also supplies the power to the electrical load.

3. A fuel cell system as described in claim 1 or 2, characterized in that the control unit executes a third control process to supply the power from the fuel cell to the electrical load and the storage device when the specified conditions are met.

4. A fuel cell system as described in claim 1 or 2, characterized in that if the specified conditions are not met when the fuel cell system is started and the remaining charge of the storage device is less than the amount necessary to supply the power to the heater until the specified conditions are met, the control unit executes a fourth control process in which the power is supplied from the storage device to the electrical load without supplying the power from the storage device to the heater.

5. A fuel cell system as described in claim 1 or 2, characterized in that, when the output from the fuel cell to the electrical load exceeds the rated capacity of the fuel cell during power generation by the fuel cell, the control unit executes a fifth control process in which the power is supplied from the fuel cell to the electrical load and the power is supplied from the storage device to the electrical load.

6. A fuel cell system as described in claim 1 or 2, characterized in that the control unit executes a sixth control process to stop the supply of power from the storage device and the fuel cell to the electrical load when the power consumption of the electrical load exceeds the sum of the rated capacity of the fuel cell and the capacity of the storage device.

7. The fuel cell system according to claim 6, wherein the control unit executes control to issue a warning in the sixth control process.

8. The fuel cell system according to claim 1 or 2, wherein the power storage device can be supplied with the power from an external power source.

9. The fuel cell system according to claim 1 or 2, wherein the hydrogen storage container contains a hydrogen absorbing alloy that releases the hydrogen by an endothermic reaction.

10. A fuel cell system as described in claim 1 or 2, characterized in that the control unit determines whether the specified condition is met based on whether the temperature of the hydrogen storage container is lower than the supply temperature at which hydrogen can be supplied to the fuel cell, or whether the pressure of the hydrogen in the hydrogen storage container is lower than the supply pressure at which hydrogen can be supplied to the fuel cell.

11. The fuel cell system according to claim 10, wherein the control unit determines the temperature of the hydrogen storage container based on the pressure of the hydrogen in the hydrogen storage container.

12. The fuel cell system according to claim 1 or 2, further comprising a solar power generation device capable of supplying power to at least one of the heater and the power storage device.

13. The fuel cell system according to claim 1 or 2, further comprising a wind power generator capable of supplying power to at least one of the heater and the power storage device.

Images