Power supply system and control method thereof

Patent metadata

Field	Value
Publication number	US-10840527-B2
Application number	US-201716637823-A
Country	US
Kind code	B2
Filing date	Aug 14, 2017
Priority date	Aug 14, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A power supply system comprising: power storage device ( 1 ); a fuel cell ( 2 ) connecting to the power storage device ( 1 ); an auxiliary machine ( 4 ) of the fuel cell, the auxiliary machine ( 4 ) operating in a range corresponding to a voltage across the fuel cell ( 2 ); a voltage converter ( 3 ) inserted along a first line between the fuel cell ( 2 ) and the power storage device ( 1 ). The power supply system further comprising an auxiliary machine power supplying device ( 5 ) inserted between the voltage converter ( 3 ) and the power storage device ( 1 ), the power supply device for the auxiliary machine ( 5 ) being configured to supply power from at least one of the fuel cell ( 2 ) and the power storage device ( 1 ) to the auxiliary machine ( 4 ); and a switch ( 6 ) inserted along a second line different from the first line between the fuel cell ( 2 ) and the auxiliary machine ( 4 ), the switch ( 6 ) being configured to supply power to the auxiliary machine ( 4 ).

First claim

The invention claimed is:

1. A power supply system comprising:
a power storage device;
a fuel cell connecting to the power storage device, the fuel cell having an output power lower than an output power of the power storage device;
an auxiliary machine of the fuel cell, the auxiliary machine operating in a range corresponding to a voltage across the fuel cell;
a voltage converter inserted along a first line between the fuel cell and the power storage device;
a power supply device for the auxiliary machine connecting to the voltage converter and the power storage device, the power supply device for the auxiliary machine being configured to supply power from at least one of the fuel cell and the power storage device to the auxiliary machine; and
a switch inserted along a second line different from the first line between the fuel cell and the auxiliary machine, the switch being configured to supply power to the auxiliary machine.

2. The power supply system according to claim 1 , further comprising:
a sensor configured to detect a power-generating state of the fuel cell; and
a controller configured to control a state of the switch based on the sensor, wherein
the controller configured to connect or disconnects the fuel cell and the auxiliary machine via the switch in accordance with a detection signal output from the sensor.

3. The power supply system according to claim 2 , wherein
the sensor detects a voltage or a current of the fuel cell as the power-generating state, and
when output power from the fuel cell exceeds requested power from the auxiliary machine based on the voltage or the current detected by the sensor, the controller configured to connect the fuel cell and the auxiliary machine.

4. The power supply system according to claim 3 , wherein
when output power from the fuel cell does not exceed requested power from the auxiliary machine, the controller configured to disconnect the fuel cell and the auxiliary machine.

5. The power supply system according to claim 2 , wherein
the sensor detects a temperature of the fuel cell as the power-generating state, and
when the temperature detected by the sensor is equal to or larger than a predetermined threshold, the controller configured to connect the fuel cell and the auxiliary machine.

6. The power supply system according to claim 5 , wherein
when the temperature detected by the sensor is less than the predetermined threshold, the controller configured to disconnect the fuel cell and the auxiliary machine.

7. The power supply system according to claim 2 , wherein
the sensor detects a voltage and a current of the fuel cell as the power-generating state, and
the controller configured to obtain IV characteristics of the fuel cell based on the power-generating state of the fuel cell, and determines whether the IV characteristics are favorable or not relative to predetermined reference characteristics, and when the controller determines the obtained IV characteristics are favorable, the controller configured to connect the fuel cell and the auxiliary machine.

8. The power supply system according to claim 7 , wherein
when the controller determines that the obtained IV characteristics are not favorable relative to the reference characteristics, the controller configured to disconnect the fuel cell and the auxiliary machine.

9. The power supply system according to claim 2 , wherein
the sensor detects a voltage of the fuel cell as the power-generating state, and
when the voltage detected by the sensor is within the range of the voltage where the auxiliary machine is operable, the controller configured to connect the fuel cell and the auxiliary machine.

10. The power supply system according to claim 2 , wherein
when the fuel cell and the auxiliary machine connect, the controller configured to lower an output from the voltage converter so as to keep power output from the fuel cell constant.

11. The power supply system according to claim 2 , further comprising
an auxiliary machine sensor configured to detect an operating state of the auxiliary machine, wherein
the controller configured to disconnect the fuel cell and the auxiliary machine in accordance with a detection signal output from the auxiliary machine sensor.

12. The power supply system according to claim 11 , wherein
the auxiliary machine sensor detects a temperature of the auxiliary machine as the operating state, and
the controller determines whether load at the auxiliary machine is excessive or not based on the temperature detected by the auxiliary machine sensor, and when the controller determines that the load is excessive, the controller configured to disconnect the fuel cell and the auxiliary machine.

13. The power supply system according to claim 11 , wherein
the auxiliary machine sensor detects a current supplied to the auxiliary machine as the operating state, and
the controller determines whether load at the auxiliary machine is excessive or not based on the current detected by the auxiliary machine sensor, and when the controller determines that the load is excessive, the controller configured to disconnect the fuel cell and the auxiliary machine.

14. The power supply system according to claim 11 , wherein
the auxiliary machine includes an actuator configured to supply gas required for power generation to the fuel cell, and
the auxiliary machine sensor detects an operating state of a motor to drive the actuator.

15. The power supply system according to claim 2 , wherein
the power storage device includes a high-voltage battery configured to output a voltage higher than a voltage across the fuel cell, and a low-voltage battery configured to output a voltage lower than the voltage across the high-voltage battery, and
the high-voltage battery connects to a motor to drive a vehicle, and the low-voltage battery connects to the power supply device for the auxiliary machine.

16. The power supply system according to claim 15 , wherein
the controller determines whether the power supply device for the auxiliary machine is out of order or not, and when the controller determines that the power supply device for the auxiliary machine is out of order, the controller configured to connect the fuel cell and the auxiliary machine.

17. The power supply system according to claim 1 , wherein
the fuel cell includes a solid oxide fuel cell configured to receive fuel and generate power, and
and the fuel cell has an upper-limit voltage less than 60 V.

18. A control method for a power supply system including: a power storage device; an auxiliary machine of a fuel cell, the fuel cell connecting to the power storage device and having an output power lower than an output power of the power storage device, the auxiliary machine operating in a range corresponding to a voltage across the fuel cell; a voltage converter inserted between the fuel cell and the power storage device; and an power supply device for the auxiliary machine configured to convert a voltage between the voltage converter and the power storage device and supply the voltage to the auxiliary machine, the control method comprising
connecting the fuel cell and the auxiliary machine to change power to be supplied from the power supply device for the auxiliary machine to the auxiliary machine into power output from the fuel cell.

Assignees

• Nissan Motor

Inventors

• Tanaka Koichi

Classifications

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• B60L2210/10

  DC to DC converters · CPC title

• H01M8/04574

  Current · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title

• Y02E60/50

  Fuel cells · CPC title