Electric power source apparatus using fuel cell and method of controlling the same

• US 7,667,350 B2
• Filed: 10/27/2005
• Issued: 02/23/2010
• Est. Priority Date: 09/30/2004
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kanouda, Akihiko, Kikuchi, Mutsumi, Norimatsu, Yasuaki
• Primary Examiner(s): Jackson; Stephen W
• Assistant Examiner(s): Amrany; Adi
• Application Number:
  US11/259,258
• Publication Number:
  US 20060068242A1
• Time in Patent Office: 1,580 Days
• Field of Search: 307 43- 44, 307/48, 307 51- 52, 307 85- 87, 320/101, 320/124, 320127-130, 320/135, 320/137, 320/166
• US Class Current: 307/87
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 2250/30 Fuel cells in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 8/04186 of liquid-charged or electrolyte-charged reactants
• CPC Class Codes: H01M 8/04365 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/04544 Voltage
• CPC Class Codes: H01M 8/04567 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04731 of other components of a fuel cell or fuel cell stacks
• CPC Class Codes: H01M 8/04865 Voltage
• CPC Class Codes: H01M 8/04888 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04947 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/1011 Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
• 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: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A method of controlling an electric power source apparatus, which comprises supplying electric power to an electronic device on which a secondary battery is mounted from a power source apparatus having a fuel cell and an auxiliary power source. Electric power is supplied intermittently to a charging terminal of the electronic device by means of a switch for controlling conduction and interruption of an output terminal of the power source apparatus.

Claims

1. A method of controlling an electric power source for supplying electric power to a charging terminal of an electronic device on which a secondary battery is mounted, wherein the electric power source is an external battery charger for the secondary battery of the electronic device and comprises a fuel cell and an auxiliary power source connected to the fuel cell in parallel and an output terminal of the electric power source can be connected to the charging terminal of the electronic device, the method comprising:

supplying the electric power to the charging terminal of the electronic device from the fuel cell and the auxiliary electric power source to charge the secondary battery by turning on the output terminal side of the electric power source at the time when a voltage of the auxiliary power source reaches an upper-limit threshold of a charging voltage of the auxiliary power source,

interrupting the supply of the electric power to the charging terminal of the electronic device and charging instead the auxiliary electric power source from the fuel cell by turning off the output terminal side of the electric power source at the time when the voltage of the auxiliary power source reaches a lower-limit threshold of a discharge voltage of the auxiliary power source,

repeating the turn-on and turn-off at the output terminal side of the electric power source, thereby supplying the electric power intermittently from the electric power source to the charging terminal of the electronic device to charge the secondary battery in direct current pulses, and

increasing the lower-limit threshold value of the discharge voltage of the auxiliary electric power source in response to an elevation in temperature of the fuel cell.

2. The controlling method according to claim 1, wherein the upper threshold value of the charging voltage of the auxiliary electric power source is increased in response to the an elevation in temperature of the fuel cell.

3. The controlling method according to claim 1, wherein the auxiliary electric power source is an electric double layer condenser.

4. The controlling method according to claim 1, wherein data on the lower threshold value of the discharge voltage and/or the upper threshold voltage of the charging voltage of the auxiliary electric power source is memorized in a memory device, whereby the charging voltage of the auxiliary voltage is changed by means of the data.

5. An electric power source apparatus for supplying electric power to a charging terminal of an electronic device on which a secondary battery is mounted, wherein the electric power source is an external battery charger for the secondary battery of the electronic device, and an output terminal of the electric power source can be connected to the charging terminal of the electronic device, the electric power source comprising:

a fuel cell,

an auxiliary electric power source functioning as a high output density power source, wherein the fuel cell and the auxiliary power source are connected to each other in parallel, and

a controlling means that supplies electric power to the charging terminal of the electronic device from the fuel cell and the auxiliary electric power source to charge the secondary battery of the electronic device by turning on the output terminal side of the electric power source at the time when a voltage of the auxiliary power source reaches an upper-limit threshold of a charging voltage of the auxiliary power source, interrupts the supply of the electric power to the charging terminal of the electronic device and, charges instead the auxiliary electric power source from the fuel cell by turning off the output terminal side of the electric power source at the time when the voltage of the auxiliary power source reaches a lower-limit threshold of a discharge voltage of the auxiliary power source, and increases the lower-limit threshold value of the discharge voltage of the auxiliary electric power source in response to an elevation in temperature in the fuel cell.

6. The electric power source apparatus according to claim 5, wherein the upper threshold value of the charging voltage of the auxiliary electric power source is increased in response to the an elevation in temperature of the fuel cell.

7. The electric power source apparatus according to claim 5, wherein the auxiliary electric power source is an electric double layer condenser.

8. The electric power source apparatus according to claim 5, further comprising:

means for memorizing data of the lower threshold value of the discharge voltage or the upper threshold value of the charging voltage of the auxiliary electric power source, wherein the control means changes the charging or discharge voltage of the auxiliary electric power source, based on the data of the lower threshold value or the upper limit threshold value in the memorizing means.