Power source circuit for cell and cell pack

• US 20040196004A1
• Filed: 03/31/2004
• Published: 10/07/2004
• Est. Priority Date: 04/07/2003
• Status: Abandoned Application

• Current Assignee: NEC Tokin Corporation (Yageo Corporation)
• Original Assignee: NEC Tokin Corporation (Yageo Corporation)
• Inventors: Sasaki, Hiroshi
• Application Number:
  US10/813,171
• Publication Number:
  US 20040196004A1
• Time in Patent Office: Days
• US Class Current: 320/127
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient

Abstract

A power source circuit for a cell and a cell pack are provided which are capable of operating them, when warnings of operation termination are displayed during use of a portable terminal device, as an emergency operation, in such a case where operation time of the portable terminal device is shortened extremely due to degradation in a discharge characteristic of the cell or due to a voltage drop occurring when the cell is used in a low temperature state. The portable terminal device is operated in a manner that a voltage output from the cell power source circuit is made higher than its operation lower limit voltage when a discharge voltage of the cell becomes lower than its operation lower limit voltage and, as a factor for detecting termination of discharge, the discharge termination is detected according to an amount of voltage drop in the cell per unit time.

Claims

1. A power source circuit for a cell for controlling transfer of electric energy from said cell to loads, wherein a device employing said power source circuit is operated in a manner that, when a discharge voltage of said cell becomes lower than an operation lower limit voltage of said device to be operated, a voltage output from said power source circuit for said cell is made higher than said operation lower limit voltage of said device by using a voltage increasing unit.

2. The power source circuit for a cell according to claim 1, wherein an amount of voltage drop in said cell per unit time is employed as a factor for detecting termination of discharge of said cell.

3. A power source circuit for a cell for controlling transfer of electric energy from said cell to loads, said power source circuit comprising a cell voltage detecting circuit to detect a voltage of said cell, a discharge controlling circuit, an output voltage detecting circuit, a step-up DC-DC converter, a switching circuit to switch a positive electrode of said cell to either of an output terminal of said power source circuit or an inputting section of said step-up DC-DC converter, and a power storing section mounted in an outputting section of said power source circuit,

wherein said device employing said power source cell is operated in a manner that, when a discharge voltage of said cell becomes lower than an operation lower limit voltage of said device to be operated, a voltage output from said power source circuit for said cell is made higher than said operation lower limit voltage of said device by using said step-up DC-DC converter.

4. The power source circuit for a cell according to claim 3, wherein an amount of voltage drop in said cell per unit time is employed as a factor for detecting termination of discharge of said cell.

5. The power source circuit for a cell according to claim 3, wherein said power storing section comprises an electric double layer capacitor.

6. A power source circuit for a cell for controlling transfer of electric energy from said cell to loads, said power source circuit comprising a cell voltage detecting circuit to detect a voltage of said cell, a control circuit, an output voltage detecting circuit, a step-up DC-DC converter, an inductor, two or more switching circuits, a power storing section mounted in said outputting section, wherein said device employing said power source cell is operated in a manner that, when a discharge voltage of said cell becomes lower than an operation lower limit voltage of said device to be operated, a voltage output from said power source circuit for said cell is made higher than said operation lower limit voltage of said device by using said step-up DC-DC converter.

7. The power source circuit for a cell according to claim 6, wherein an amount of voltage drop in said cell per unit time is employed as a factor for detecting termination of discharge of said cell.

8. The power source circuit for a cell according to claim 6, wherein said power storing section comprises an electric double layer capacitor.

9. A cell pack comprising a cell, a power source circuit for said cell for controlling transfer of electric energy from said cell to loads, and a case for housing the power source circuit and the cell therein,

wherein a device employing said power source circuit is operated in a manner that, when a discharge voltage of said cell becomes lower than an operation lower limit voltage of said device to be operated, a voltage output from said power source circuit for said cell is made higher than said operation lower limit voltage of said device by using a voltage increasing unit.

10. The cell pack according to claim 9, wherein said cell is a primary cell or a secondary cell.

11. A cell pack comprising a cell, a power source circuit for said cell for controlling transfer of electric energy from said cell to loads, and a case for housing the power source circuit and the cell therein,

wherein said power source circuit comprises a cell voltage detecting circuit to detect a voltage of said cell, a discharge controlling circuit, an output voltage detecting circuit, a step-up DC-DC converter, a switching circuit to switch a positive electrode of said cell to either of an output terminal of said power source circuit or an inputting section of said step-up DC-DC converter, and a power storing section mounted in an outputting section of said power source circuit, wherein said device employing said power source cell is operated in a manner that, when a discharge voltage of said cell becomes lower than an operation lower limit voltage of said device to be operated, a voltage output from said power source circuit for said cell is made higher than said operation lower limit voltage of said device by using said step-up DC-DC converter.

12. The cell pack according to claim 11, wherein said cell is a primary cell or a secondary cell.

13. A cell pack comprising a cell, a power source circuit for said cell for controlling transfer of electric energy from said cell to loads, and a case for housing the power source circuit and the cell therein,

wherein said power source circuit comprises a cell voltage detecting circuit to detect a voltage of said cell, a control circuit, an output voltage detecting circuit, a step-up DC-DC converter, an inductor, two or more switching circuits, a power storing section mounted in said outputting section, wherein said device employing said power source cell is operated in a manner that, when a discharge voltage of said cell becomes lower than an operation lower limit voltage of said device to be operated, a voltage output from said power source circuit for said cell is made higher than said operation lower limit voltage of said device by using said step-up DC-DC converter.

14. The cell pack according to claim 13, wherein said cell is a primary cell or a secondary cell.