Method and apparatus for recharging batteries using a step shaped voltage pulse

• US 5,777,453 A
• Filed: 03/27/1996
• Issued: 07/07/1998
• Est. Priority Date: 09/26/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha JNT
• Original Assignee: Kabushiki Kaisha JNT
• Inventors: Imanaga, Eisuke
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US08/624,864
• Time in Patent Office: 832 Days
• Field of Search: 320/2, 320/5, 320/14, 320/15, 320/20, 320/21, 320/22, 320/25, 320/30, 320/39, 320/40
• US Class Current: 320/160
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process

Abstract

The present invention relates to a method of charging a battery, including applying a voltage pulse to a rechargeable battery, detecting a terminal voltage and a charging current, comparing detected results to known standards and continuing charging if necessary. A charging device having movable contact terminals is also disclosed.

Claims

1. A second battery charging method comprising the steps of:

applying, to positive and negative terminals of a secondary battery, a voltage pulse having a step shape, whose voltage is reduced as time elapses and in consonance with a characteristic of said secondary battery, and supplying a corresponding current, with said voltage pulse having a pulse height of at least 1.3 times a pulse height of a terminal voltage for said secondary battery;

detecting said terminal voltage of said secondary battery during a pulse halted period and a charging current during a pulse duration;

comparing detected results with standard characteristic data concerning said secondary battery, and making a determination concerning a waveform for said voltage pulse and said pulse duration by employing results obtained from such comparisons;

continuing a charging process in consonance with results obtained by said determination; and

performing rapid charging while preventing occurrence of overcharging, overheating, and memory effect in said secondary battery.

2. A secondary battery charging method according to claim 1, wherein said secondary battery is a nickel-cadmium battery, and a characteristic of said voltage pulse is matched with said nickel-cadmium battery.

3. A secondary battery charging method according to claim 1, wherein said secondary battery is a nickel-hydrogen battery, and a characteristic of said voltage pulse is matched with said nickel-hydrogen battery.

4. A secondary battery charging method as in one of claims 1-3, wherein said pulse height of said voltage pulse is so selected as to be 1.5 to 3 times said terminal voltage of said secondary battery.

5. A secondary battery charging device comprising:

a power source for generating a voltage to charge a secondary battery;

a power controller for controlling, upon receipt of said voltage from said power source, a pulse height and a pulse duration of an output voltage pulse in consonance with a control signal from an external source, and for generating said voltage pulse that has a height at least 1.3 times a pulse height of a terminal voltage for said secondary battery;

a monitoring unit for detecting a charging current during a charging period using said voltage pulse and said terminal voltage of said secondary battery during a voltage pulse halted period, and for monitoring a condition of said secondary battery by comparing standard data for characteristics of said secondary battery with said charging current and said terminal voltage that are detected; and

a calculation and driving unit for performing, upon receipt of an output by said monitoring unit, a predetermined calculation so as to match said characteristics of said secondary battery, and for driving said power controller in consonance with results obtained by said predetermined calculation.

6. A secondary battery charging device according to claim 5, wherein said monitoring unit and said calculation and driving unit match a characteristic of a nickel-cadmium battery.

7. A secondary battery charging device according to claim 5, wherein said monitoring unit and said calculation and driving unit match a characteristic of a nickel-hydrogen battery.

8. A secondary battery charging device according to claim 5, wherein said monitoring unit and said calculation and driving unit selectively match characteristics of a nickel-cadmium battery, a nickel-hydrogen battery, and other secondary battery.

9. A secondary battery charging method as in one of claims 5-8, wherein said pulse height of said voltage pulse is so selected as to be 1.5 to 3 times said terminal voltage of said secondary battery.