Fuel cell system having secondary cell

• US 20050233192A1
• Filed: 06/14/2005
• Published: 10/20/2005
• Est. Priority Date: 12/16/2002
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nishiyama, Katsuhiko, Yoshida, Hiroshi, Ishikawa, Tetsuhiro, Yano, Tsuyoshi, Matsumoto, Tadaichi
• Granted Patent: US 7,354,671 B2
• Time in Patent Office: Days
• US Class Current: 429/432
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04223 during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
• CPC Class Codes: H01M 8/04228 during shut-down
• CPC Class Codes: H01M 8/04303 applied during shut-down
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04567 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04664 Failure or abnormal function
• CPC Class Codes: H01M 8/04865 Voltage
• CPC Class Codes: H01M 8/04917 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

This invention provides a power supply system for supplying electrical power to a load. The system includes: a first and a second power supply wirings for a connection to the load; a fuel cell system having a fuel cell connected between the first and second power supply wiring; a secondary power supply system connected in parallel to the fuel cell between the first power supply wiring and the second power supply wiring; a switch for opening and closing the connection between the fuel cell and the first power supply wiring; a countercurrent prevention device connected between the fuel cell and the first power supply wiring; and a controller for controlling the secondary power supply system and the switch. The controller controls the secondary power supply system to boost a terminal voltage of the secondary power supply system to a first voltage, when connecting the fuel cell to the first power supply wiring. The first voltage is equal or higher than an electrical potential difference of the open terminals of the fuel cell.

Claims

1. A power supply system for supplying electrical power to a load, comprising:

a power supply wiring for a connection to the load;

a fuel cell system including a fuel cell connectable to the power supply wiring;

a secondary power supply system connectable to the fuel cell via the power supply wiring;

a switch for opening and closing a connection between the fuel cell and the power supply wiring; and

a controller for controlling the secondary power supply system and the switch, wherein

the controller is configured to control the secondary power supply system to boost a terminal voltage of the secondary power supply system to a first voltage, when connecting the fuel cell to the power supply wiring, the first voltage being equal or higher than an electrical potential difference of the fuel cell.

2. The power supply system according to claim 1, wherein

the controller is configured to drop the terminal voltage of the secondary power supply system to a second voltage, after connecting the fuel cell to the power supply wiring, the second voltage being lower than an electrical potential difference of the fuel cell.

3. The power supply system according to claim 1, wherein

the controller is configured to drop the terminal voltage of the secondary power supply system to a voltage lower than an electrical potential difference of the fuel cell, in response to isolation of the fuel cell from the power supply wiring.

4. The power supply system according to claim 3, wherein

the secondary power supply system comprises a rechargeable secondary cell, and a DC-DC converter able to boost or drop a voltage of DC input power input from the secondary cell, for outputting DC power;

and

the controller is configured to initiate control so as to bring the output voltage of the DC-DC converter closer to the output voltage of the secondary cell than the electrical potential difference of the fuel cell, in response to isolation of the fuel cell from the power supply wiring.

5. The power supply system according to claim 3, wherein

the secondary power supply system comprises a rechargeable secondary cell, and a DC-DC converter able to boost or drop a voltage of DC input power input from the secondary cell, for outputting DC power;

and

the controller is configured to initiate control so as to bring the output voltage of the DC-DC converter close to the output voltage of the secondary cell, in response to isolation of the fuel cell from the power supply wiring.

6. The power supply system according to claim 1, wherein

the controller is configured to isolate the fuel cell from the power supply wiring when the fuel cell is in a state of inability to supply a predetermined magnitude of electrical power.

7. A control apparatus for controlling a power supply system to provide electrical power to a load, wherein

the power supply system comprises:

a power supply wiring and for a connection to the load;

a fuel cell system including a fuel cell connectable to the power supply wiring;

a secondary power supply system connectable to the fuel cell via the power supply wiring;

a switch for opening and closing a connection between the fuel cell and the power supply wiring; and

the controller is configured to control the secondary power supply system to boost a terminal voltage of the secondary power supply system when controlling the switch to connect the fuel cell to the power supply wiring.

8. A method of providing electrical power to a load, comprising the steps of:

(a) providing a power supply wiring for a connection to the load, a fuel cell system including a fuel cell connectable to the power supply wiring, a secondary power supply system connectable to the fuel cell via the power supply wiring, a switch for opening and closing a connection between the fuel cell and the power supply wiring, and

(b) controlling the secondary power supply system and the switch, wherein

the step (b) includes the step of controlling the secondary power supply system to boost a terminal voltage of the secondary power supply system to a first voltage, when connecting the fuel cell to the power supply wiring, the first voltage being equal or higher than an electrical potential difference of the fuel cell.

9. A power supply system for supplying electrical power to a load, comprising:

a fuel cell system including a fuel cell connectable to the load via a power supply wiring;

a secondary power supply system connectable to the fuel cell;

a switch for opening and closing a connection between the fuel cell and the power supply wiring; and

a controller for controlling the secondary power supply system, wherein

the controller is configured to have a specific control mode to open the switch to halt an output of the fuel cell.

10. The power supply system according to claim 9, wherein

the secondary power supply system comprises a rechargeable secondary cell, and a DC-DC converter able to boost or drop a voltage of DC input power input from the secondary cell, for outputting DC power, wherein

the DC-DC converter has a short circuit mode for shorting the rechargeable secondary cell and the fuel cell, and further wherein

the specific control mode is a control mode for setting an operation mode of the DC-DC converter to the short circuit mode.

11. The power supply system according to claim 10, wherein

the rechargeable secondary cell is configured to output a predetermined electrical power at a voltage of a terminal voltage equal or higher than an electrical potential difference of the fuel cell.

12. The power supply system according to claim 9, wherein

the controller is configured to control in the specific control mode in a specific state including at least one of a startup of the fuel cell and a malfunction of the fuel cell.

13. The power supply system according to claim 10, wherein

the rechargeable secondary cell has a first power terminal and a second power terminal, wherein

the DC-DC converter comprises:

a first load terminal;

second load terminal;

second power side series circuit having a first switch and a second switch, one terminal of the first switch and one terminal of the second switch being connected at a first connection point, the other terminal of the first switch being connected to the first power terminal, the other terminal of the second switch being connected to the second power terminal;

a load side series circuit having a third switch and a fourth switch, one terminal of the third switch and one terminal of the fourth switch being connected at a second connection point, the other terminal of the third switch being connected to the first load terminal, the other terminal of the fourth switch being connected to the second load terminal; and

an inductance connected between the first connection point and the second connection point, wherein

the second power terminal is connected to the second load terminal, wherein

the short circuit mode is an operation mode for the controller closing the first switch and the third switch, and also opening the connection control switch and the second switch and the fourth switch.

14. A fuel cell automobile equipped with a fuel cell, comprising:

the power supply system according to claim 9;

and

a drive unit configured to drive a wheel rotary with electrical power provided from the power supply system, wherein

the controller comprises;

an secondary power system observer configured to estimate an available electrical power that the secondary power system can provide; and

a requesting power determiner configured to control a requesting electrical power of the drive unit in response to the estimated available electrical power.

15. The fuel cell automobile according to claims 14, wherein

the secondary power system observer measures a voltage of the provided electrical power from the secondary power system, wherein

the requesting power determiner is configured to further control the requesting electrical power of the drive unit in response to the measured voltage.

16. A control apparatus for controlling a power supply system to provide power to a load, wherein

the power supply system comprises:

a fuel cell system having a countercurrent prevention device and a fuel cell, one terminal of the countercurrent prevention device being connected to one terminal of the load, the fuel cell connected between the other terminal of the load and connectable to the other terminal of the countercurrent prevention device;

a secondary power supply system connected in parallel to the fuel cell; and

a switch for opening and closing a connection between the fuel cell and a power supply wiring to supply power to the load, wherein

the controller is configured to have a specific control mode to open the switch to halt an output of the fuel cell.

17. A method of providing electrical power to a load, comprising:

(a) providing a fuel cell system having a countercurrent prevention device and a fuel cell, one terminal of the countercurrent prevention device being connected to one terminal of the load, the fuel cell connected between the other terminal of the load and connectable to the other terminal of the countercurrent prevention device and a switch for opening and closing a connection between the fuel cell and a power supply wiring to supply power to the load; and

(b) controlling the secondary power supply system and the switch, wherein

the step (b) has a specific control mode to open the switch to halt an output of the fuel cell.