JP2023030368A - fuel cell system - Google Patents

Abstract

To provide a technology that enables maintenance of a fuel cell stack at all times and suppresses wasteful consumption of electric power of a battery provided in a fuel cell system.SOLUTION: A fuel cell system disclosed herein includes a fuel cell stack, a first electrical device involved in maintenance of the fuel cell stack, a second electrical device not involved in maintenance of the fuel cell stack, a first battery that powers the first electrical device, a second battery that powers the second electrical device, and a relay that disconnects the second battery from the second electrical device.SELECTED DRAWING: Figure 1

Description

The technology disclosed in this specification relates to a fuel cell system.

A vehicle equipped with a fuel cell system is disclosed in Patent Document 1. Fuel cell stacks require electrical devices for operation and start-up. To start or operate the fuel cell stack, the fuel cell system is equipped with a battery. On the other hand, the vehicle is also equipped with electrical devices, such as radios, that are not related to fuel cell stack start-up and operation.

JP 2017-016746 A

Since the fuel cell stack needs to periodically perform maintenance operations such as draining water, even when the vehicle is stopped (when the vehicle's main switch is turned off), the electrical The device must be powered. That is, electrical devices involved in maintenance of the fuel cell stack must always be connected to the battery. On the other hand, electrical devices that are not involved in the maintenance of the fuel cell stack (e.g. radios) do not need to be powered while the vehicle is stationary (while the vehicle's main switch is off). . If an electrical device that is not related to maintenance is always connected to the battery, the power of the battery is wasted by the dark current that flows from the battery to the electrical device that is not related to maintenance. The present specification provides a technology that enables constant maintenance of a fuel cell stack and suppresses wasteful consumption of electric power of a battery provided in a fuel cell system.

The fuel cell system disclosed herein includes a fuel cell stack, a first electrical device involved in maintenance of the fuel cell stack, a second electrical device not involved in maintenance of the fuel cell stack, and power to the first electrical device. A first battery for supplying power, a second battery for supplying power to a second electrical device, and a relay for isolating the second battery from the second electrical device. The first electrical device and the first battery are always connected and the first electrical device can be operated at any time. On the other hand, by opening the relay when there is no need to energize the second electric device, dark current does not flow from the second battery to the second electric device, and wasteful consumption of electric power of the second battery is suppressed. . The fuel cell system disclosed in this specification can be applied to other than vehicles. For example, the fuel cell system disclosed in this specification can also be applied as an emergency power supply in the event of a disaster. In that case, an example of the second electrical device is a light that illuminates the control panel of the fuel cell system.

Details and further improvements of the technique disclosed in this specification are described in the following "Mode for Carrying Out the Invention".

1 is a block diagram of a fuel cell system of an embodiment; FIG. 1 is a block diagram of a fuel cell system of a reference example; FIG.

A fuel cell system 10 of an embodiment will be described with reference to FIG. A fuel cell system 10 is mounted on a vehicle 2 . FIG. 1 is a block diagram of an automobile 2 including a fuel cell system 10. As shown in FIG. The automobile 2 has a motor 4 for running. The fuel cell system 10 includes a fuel cell stack 13 , and the output power (direct current) of the fuel cell stack 13 is converted into alternating current power by the inverter 3 and supplied to the motor 4 .

The fuel cell system 10 includes a fuel cell stack 13, a first battery 11, a second battery 12, a fuel cell controller 16, a water drain pump 15, an automobile controller 22, a relay 21, a radio 24, and a light 25. there is The fuel cell system 10 also includes a hydrogen tank, a compressor for compressing air to be sent to the fuel cell stack 13, various pumps, a cooler, a gas-liquid separator, etc., but these are not shown. In addition, dashed arrow lines in FIG. 1 represent signal lines.

The output voltage of the fuel cell stack 13 is 100 volts or higher. The output voltages of the first battery 11 and the second battery 12 are lower than the output voltage of the fuel cell stack 13, for example, 50 volts or less. The output of the fuel cell stack 13 is used to drive the motor 4 , and the first battery 11 and the second battery 12 supply power to small power devices other than the motor 4 .

Fuel cell system 10 further includes a step-down converter 17 . While the fuel cell stack 13 is generating power, the step-down converter 17 steps down the output of the fuel cell stack 13 and supplies it to the first battery 11 and the second battery 12 . That is, the first battery 11 and the second battery 12 are charged with the electric power of the fuel cell stack 13 .

The fuel cell stack 13 needs to drain water periodically, and the drain pipe 14 of the fuel cell stack 13 is equipped with a pump 15 for draining water. The fuel cell controller 16 activates the pump 15 at regular time intervals to remove water accumulated in the fuel cell stack 13 . The fuel cell controller 16 and the pump 15 operate with power supplied from the first battery 11 . The fuel cell controller 16 and the pump 15 are electrically directly connected to the first battery 11 and are always supplied with power from the first battery 11, including while the fuel cell stack 13 is stopped. The fuel cell system 10 can drain water from the fuel cell stack 13 even when the main switch 5 of the automobile 2 is off.

On the other hand, a radio 24 and a light 25 are connected to the second battery 12 via a relay 21 . A vehicle controller 22 is electrically directly connected to the second battery 12 . The vehicle controller 22 closes the relay 21 when the main switch 5 is turned on, and opens the relay 21 when the main switch 5 is turned off. When the main switch 5 is turned on, the relay 21 is closed and power is supplied from the second battery 12 to the radio 24 and the lighting 25 . When the main switch 5 is turned off, the radio 24 and lighting 25 are cut off from the second battery 12 .

The fuel cell system 10 includes two batteries (first battery 11 and second battery 12) for small power devices. The first battery 11 is electrically connected directly to the first electrical devices (the fuel cell controller 16 and the water drain pump 15) involved in the maintenance of the fuel cell stack 13. FIG. Since power is supplied to the fuel cell controller 16 and the draining pump 15 even while the main switch 5 is off, the fuel cell stack 13 can be drained periodically (or at any time). .

The second battery 12 is electrically connected via a relay 21 to a second electrical device (radio 24 and lighting 25) that is not related to fuel cell stack 13 maintenance. When the main switch 5 is off, the relay 21 is opened, disconnecting the second electrical device from the second battery 12 . While the relay 21 is open, dark current does not flow from the second battery 12 to the second electrical device, so the fuel cell system 10 of the embodiment suppresses wasteful consumption of electric power of the second battery 12. be done.

The main switch 5 is the main switch of the automobile 2 and also the main switch of the fuel cell system 10 . The fuel cell system 10 can maintain the fuel cell stack 13 even while the main switch 5 is off, and opens the relay 21 while the main switch 5 is off to prevent wasteful consumption of the power of the second battery 12 . can be suppressed.

The vehicle controller 22 is not involved in maintenance of the fuel cell stack 13, but is electrically connected directly to the second battery 12. As shown in FIG. The vehicle controller 22 is always connected to the second battery 12 because it is necessary to constantly monitor the state of the main switch 5 . In this way, some of the electrical devices not involved in maintenance of the fuel cell stack 13 may be electrically connected directly to the second battery 12 (or the first battery 11). If at least one second electrical device is connected to the second battery 12 via the relay 21, wasteful consumption of power of the second battery 12 can be suppressed.

A fuel cell system 110 of a reference example will be described with reference to FIG. A fuel cell system 110 is also mounted on the automobile 2 . While the fuel cell system 10 of the embodiment includes two batteries (the first battery 11 and the second battery 12), the fuel cell system 110 of the reference example does not include the second battery 12. Only the first battery 11 is provided for the low power devices (the first electrical device and the second electrical device).

The fuel cell system 110 includes the fuel cell stack 13 , first electrical devices (drainage pump 15 and fuel cell controller 16 ) necessary for maintaining the fuel cell stack 13 , and maintenance of the fuel cell stack 13 . a second electrical device (radio 24, lighting 25), a first battery 11, and a relay 21; The first electrical device is electrically directly connected to the first battery 11 and the second electrical device is connected to the first battery 11 via the relay 21 .

Except for the second battery 12, the configuration of the fuel cell system 110 of the reference example is the same as the configuration of the fuel cell system 10 of the embodiment. In the fuel cell system 110, the first electrical devices (the fuel cell controller 16 and the water drain pump 15) involved in the maintenance of the fuel cell stack 13 are electrically connected directly to the first battery 11, and the fuel cell stack 13 A second electrical device (radio 24 and light 25 ) not involved in the maintenance of the battery is connected to the first battery 11 via a relay 21 .

When the main switch 5 is off, the relay 21 is opened. The fuel cell system 110 of the reference example can also perform maintenance (e.g. draining water) of the fuel cell stack 13 at any time, and when the main switch 5 is off, the relay 21 opens and the second electrical device switches to the first electrical device. It is cut off from the battery 11 . Wasteful consumption of the power of the first battery 11 can be suppressed.

In the fuel cell system 110 of the reference example as well, the vehicle controller 22 that is not involved in maintenance of the fuel cell stack 13 is electrically connected directly to the first battery 11 . If at least one second electrical device is connected to the first battery 11 via the relay 21, wasteful consumption of electric power of the first battery 11 can be suppressed.

Points to note regarding the techniques of the examples and reference examples will be described. The fuel cell system disclosed in the present specification can be applied to devices other than automobiles, such as power supply systems during disasters. The technology disclosed in this specification is preferably applied to commercial vehicles in which the main switch is frequently turned on and off.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or in the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims as of the filing. In addition, the techniques exemplified in this specification or drawings can simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

2: Automobile 3: Inverter 4: Motor 5: Main switch 10: Fuel cell system 11: First battery 12: Second battery 13: Fuel cell stack 14: Drain pipe 15: Pump 16: Fuel cell controller 17: Buck converter 21 : Relay 22: Automobile controller 24: Radio 25: Lighting 110: Fuel cell system (reference example)

Claims (1)

a fuel cell stack;
a first electrical device involved in maintenance of the fuel cell stack;
a second electrical device not involved in maintenance of the fuel cell stack;
a first battery that powers the first electrical device;
a second battery for powering the second electrical device;
a relay that disconnects the second battery from the second electrical device;
A fuel cell system with

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