POWER SUPPLY DEVICE

• US 20100143812A1
• Filed: 02/19/2010
• Published: 06/10/2010
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Takada, Masahiro, Ichinose, Toshihiko, Kuranaka, So, Kozu, Katsumi, Shibutani, Satoshi
• Granted Patent: US 8,470,481 B2
• Time in Patent Office: Days
• US Class Current: 429/428
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/04186 of liquid-charged or electrolyte-charged reactants
• CPC Class Codes: H01M 8/04656 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/1009 with one of the reactants being liquid, solid or liquid-charged H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A clean power supply unit with a high fuel utilization rate using a fuel cell is provided. The power supply unit of the present invention comprises a fuel cell using methanol as fuel; a secondary battery for supplying power to a load; a fuel cell control part for controlling the amount of fuel and/or air supplied to the above-mentioned fuel cell; and a power converter for converting the power output from the above-mentioned fuel cell to a predetermined voltage or current, supplying power to the load and/or the above-mentioned secondary battery and controlling the supplied power so as to fall within a predetermined range including the value at which the amount of methanol discharged from the above-mentioned fuel cell becomes minimized.

Claims

1. A power supply unit comprising:

a fuel cell using methanol as fuel;

a secondary battery for supplying power to a load;

a fuel cell control part for supplying a certain amount of fuel per unit of time to said fuel cell in at least predetermined power generation mode; and

a power converter for converting the power output from said fuel cell to a predetermined voltage or current, supplying power to the load and/or said secondary battery, supplying a certain amount of fuel per unit of time to said fuel cell and controlling the supplied power so as to fall within a predetermined range including the value at which the output power of said fuel cell becomes maximized.

2. A power supply unit as stated in claim 1, wherein said power converter controls the output current of said fuel cell to become a target current, and said target current has a value greater than the output current value at which the output power of said fuel cell substantially becomes maximized by a predetermined value.

3. A power supply unit as stated in claim 1, wherein said power converter controls the output voltage of said fuel cell to become a target voltage, and said target voltage has a value lower than the output voltage value at which the output power of said fuel cell substantially becomes maximized by a predetermined value.

4. A power supply unit as stated in claim 1 further comprising a secondary battery residual capacity detector for detecting the residual capacity of said secondary battery, wherein said fuel cell control part has a plurality of power generation modes that are switched based on at least residual capacity of said secondary battery and supplies a certain amount of fuel per unit of time as a value varying among power generation modes to said fuel cell.

5. A power supply unit as stated in claim 4, wherein said secondary battery residual capacity detector detects the residual capacity of said secondary battery based on the voltage of said secondary battery.

6. A power supply unit as stated in claim 1, wherein said fuel cell is a balance type fuel cell that keep a balance between the fuel and the output power of said fuel cell.

7. A power supply unit as stated in claim 4, wherein when the residual capacity of said secondary battery decreases and reaches a first residual capacity, the amount of fuel supplied to said fuel cell is switched from the first value to a second value greater than said first value, and when the residual capacity of said secondary battery increases and reaches the second residual capacity greater than said first residual capacity, the amount of fuel supplied to said fuel cell is switched from said second value to said first value.

8. A power supply unit as stated in claim 4, wherein said fuel cell control part has at least three power generation modes.

9. A power supply unit as stated in claim 8, wherein said three values are a maximum value, an intermediate value and a minimum value,

in the state where the amount of fuel supplied to said fuel cell is the intermediate value, when the residual capacity of said secondary battery reaches a maximum threshold, the amount of fuel supplied to said fuel cell is switched to the minimum value,

in the state where the amount of fuel supplied to said fuel cell is the minimum value, when the residual capacity of said secondary battery decreases and reaches an intermediate threshold, the amount of fuel supplied to said fuel cell is switched to the intermediate value,

in the state where the amount of fuel supplied to said fuel cell is the intermediate value, when the residual capacity of said secondary battery decreases and reaches a minimum threshold, the amount of fuel supplied to said fuel cell is switched to the maximum value, and

in the state where the amount of fuel supplied to said fuel cell is of maximum value, when the residual capacity of said secondary battery increases and reaches said intermediate threshold, the amount of fuel supplied to said fuel cell is switched to the intermediate value.

10. A power supply unit as stated in claim 8, wherein said three values are a maximum value, an intermediate value and a minimum value,

in the state where the amount of fuel supplied to said fuel cell is the intermediate value, when the residual capacity of said secondary battery reaches a maximum threshold, the amount of fuel supplied to said fuel cell is switched to the minimum value,

in the state where the amount of fuel supplied to said fuel cell is the minimum value, when the residual capacity of said secondary battery decreases and reaches a first intermediate threshold, the amount of fuel supplied to said fuel cell is switched to the intermediate value,

in the state where the amount of fuel supplied to said fuel cell is the intermediate value, when the residual capacity of said secondary battery decreases and reaches a minimum threshold, the amount of fuel supplied to said fuel cell is switched to the maximum value, and

in the state where the amount of fuel supplied to said fuel cell is of maximum value, when the residual capacity of said secondary battery increases and reaches a second intermediate threshold, the amount of fuel supplied to said fuel cell is switched to the intermediate value.

11. A power supply unit as stated in claim 4, wherein when said fuel cell increases the output power, the amount of fuel is increased and then the power supplied by said power converter is increased, and said fuel cell decreases the output power, the power supplied by said power converter is decreased and then the amount of fuel is decreased.

12. A power supply unit as stated in claim 4, wherein in the power generation mode where the amount of fuel supplied to said fuel cell is the minimum value, the output power of said fuel cell is substantially same as a self-power consumption of the power supply unit.

13. A power supply unit as stated in claim 4, wherein when said power supply unit is activated, said fuel cell control part sets the power generation mode where the amount of fuel supplied to said fuel cell is the minimum value as an initialization mode.