Method and system for controlling energy supply in fuel cell vehicle

Patent metadata

Field	Value
Publication number	US-10367216-B2
Application number	US-201715623255-A
Country	US
Kind code	B2
Filing date	Jun 14, 2017
Priority date	Jan 9, 2017
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

A method of controlling energy supply in a fuel cell vehicle includes storing an output current of a fuel cell as a pre-limited current when a cell voltage ratio reaches a minimum cell voltage ratio, setting a limited output current of the fuel cell as the pre-limited current when the cell voltage ratio reaches a hazard cell voltage ratio, connecting first and second high-voltage batteries to a main bus terminal in parallel when the cell voltage ratio reaches the hazard cell voltage ratio, and outputting a supplementary current from the second high-voltage battery by an insufficient amount of the output current of the fuel cell for the pre-limited current, and a system for performing the same.

First claim

What is claimed is:

1. A method of controlling energy supply in a fuel cell vehicle, comprising steps of:
storing an output current of a fuel cell as a pre-limited current when a cell voltage ratio, which is obtained by dividing a minimum cell voltage by an average cell voltage, reaches a minimum cell voltage ratio;
monitoring the cell voltage ratio;
setting a limited output current of the fuel cell as the pre-limited current when the cell voltage ratio reaches a hazard cell voltage ratio;
connecting first and second high-voltage batteries to a main bus terminal in parallel when the cell voltage ratio reaches the hazard cell voltage ratio; and
outputting a supplementary current from the second high-voltage battery by an insufficient amount of the output current of the fuel cell for the pre-limited current when the output current of the fuel cell reaches a predetermined range of the limited output current that is set as the pre-limited current.

2. The method according to claim 1 , wherein the minimum cell voltage ratio is a minimum value at which no inverse voltage is generated when an output is generated in the fuel cell.

3. The method according to claim 1 , wherein the hazard cell voltage ratio is greater than the minimum cell voltage ratio.

4. The method according to claim 1 , wherein, in the step of setting the limited output current of the fuel cell as the pre-limited current, when the cell voltage ratio reaches the hazard cell voltage ratio and a drop rate of change in the minimum cell voltage is higher than a drop rate of change in the average cell voltage, the limited output current of the fuel cell is set as the pre-limited current.

5. The method according to claim 1 , further comprising connecting the first and second high-voltage batteries in series when an ignition key or ignition of a vehicle is off.

6. The method according to claim 1 , wherein, in the step of connecting first and second high-voltage batteries to the main bus terminal in parallel, when the cell voltage ratio reaches the hazard cell voltage ratio, a required output for a system is generated only by the fuel cell, and the first and second high-voltage batteries are boosted, such that a voltage at each output end thereof reaches a voltage at an output end of the fuel cell, and are then connected in parallel to the main bus terminal.

7. The method according to claim 1 , wherein, after the step of outputting the supplementary current from the second high-voltage battery, when a required output for a system is equal to or less than a reference value, the step of outputting the supplementary current from the second high-voltage battery is stopped.

8. The method according to claim 1 , wherein, in the step of storing the output current of the fuel cell as the pre-limited current, the output current of the fuel cell is stored as the pre-limited current when the cell voltage ratio reaches the minimum cell voltage ratio in a state in which a required output for a system is equal to or more than a reference value.

9. The method according to claim 1 , wherein, in the step of outputting the supplementary current from the second high-voltage battery, when the output current of the fuel cell reaches the predetermined range of the limited output current that is set as the pre-limited current, the pre-limited current is set as a limited holding current, and the supplementary current is outputted from the second high-voltage battery by an insufficient amount of the output current of the fuel cell for the limited holding current.

10. A system for controlling energy supply in a fuel cell vehicle, the system performing the method of controlling energy supply in a fuel cell vehicle according to claim 1 , the system comprising:
a switch configured to realize a division mode, in which first and second high-voltage batteries are connected in parallel to a main bus terminal through a respective first and second converter, or an integration mode in which the first and second high-voltage batteries are connected in series while being connected in parallel to the main bus terminal through the second converter;
a voltage sensor configured to detect a voltage of each fuel cell;
a memory configured to store a minimum cell voltage ratio, a hazard cell voltage ratio, a limited output current, and a pre-limited current; and
a controller for controlling driving of the switch and the fuel cell, the controller being configured to:
update the pre-limited current in the memory as an output current of the fuel cell when a cell voltage ratio reaches the minimum cell voltage ratio,
set the limited output current of the fuel cell as the pre-limited current and switch to the division mode for the first and second high-voltage batteries through the switch when the cell voltage ratio reaches the hazard cell voltage ratio, and
control the second converter so as to output a supplementary current from the second high-voltage battery by an insufficient amount of the output current of the fuel cell for the pre-limited current when the output current of the fuel cell reaches a predetermined range of the limited output current that is set as the pre-limited current.

11. The system according to claim 10 , wherein the first high-voltage battery and the first converter are connected to a first circuit, the second high-voltage battery and the second converter are connected to a second circuit, and the first and second circuits are separated from or connected to each other through first and second switches.

12. The system according to claim 11 , wherein the first switch is provided between the first high-voltage battery and the second high-voltage battery so that the first and second high-voltage batteries are separate from each other or connected in series.

13. The system according to claim 11 , wherein the second switch is provided between the first circuit and the second circuit at a point between the first and second high-voltage batteries and the first and second converters so that the first and second circuits are separated from each other or connected in series.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Jin Young Pin
• Yang Sung Ho
• Shim Jae Young
• Jeon Kang Sik
• Yu Ji Hwan

Classifications

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M8/04873

  of the individual fuel cell · CPC title

• B60L2240/549

  Current · CPC title

• H01M16/006

  of fuel cells with rechargeable batteries · CPC title

• H01M8/04559

  of fuel cell stacks · CPC title