Battery charging apparatus

• US 5,541,491 A
• Filed: 08/08/1994
• Issued: 07/30/1996
• Est. Priority Date: 07/21/1992
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yamazaki, Yasuharu, Nakamura, Shoichi
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Law, Patrick B.
• Application Number:
  US08/286,988
• Time in Patent Office: 722 Days
• Field of Search: 320/21, 320/22, 320/23, 320/24, 320/31, 320/32, 320/39, 320/40, 320/43, 320/44
• US Class Current: 320/145
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/007194 of the battery

Abstract

A battery charging apparatus for charging a chargeable battery is disclosed. The apparatus comprises: a dc power source for generating a charging current; current control means connected between the dc power source and a chargeable battery to be charged; charging controller means connected to the current control means for controlling a flow of the charging current from the dc power source to the chargeable battery; and charging condition detecting means for detecting charging condition of the chargeable battery during charging operation. The charging controller means supplies control pulse to the current control means.

Claims

1. A battery charging apparatus for charging a chargeable battery, comprising:

a dc power source for generating a charging current;

current control means connected between said dc power source and a chargeable battery to be charged;

charging controller means connected to said current control means for controlling a flow of said charging current from said dc power source to said chargeable battery, and for supplying a pulse train of control pulses to said current control means for supplying said charging current to said chargeable battery corresponding to a change in self-discharge after a completion of charging of said battery; and

charging condition detecting means for detecting when said chargeable battery is fully charged and when said chargeable battery starts discharging at a self-discharge rate;

wherein said charging controller means supplies said control pulse train to said current control means and the pulse width and the interval between the control pluses of said pulse train are selected by said charging controller means based at least upon the rate of self-discharge of said chargeable battery such that said chargeable battery receives pulses of said charging current corresponding to said control pulse train which are sufficient to affect said self-discharging.

2. A battery charging apparatus as cited in claim 1, wherein said charging controller means operates in a plurality of charging modes which are determined by a pulse width and an interval of said control pulse to be supplied to said current control means, wherein said pulses of charging current supplied to said chargeable battery have substantially the same amplitude in each of said plurality of charging modes.

3. A battery charging apparatus as cited in claim 2, wherein said plural modes includes a quick charging mode, and a trickle charging mode responsive to discharging of a charged battery.

4. A battery charging apparatus as cited in claim 3, wherein said modes further include an initial charging and a supplemental charging.

5. A battery charging apparatus as cited in claim 1, wherein said current control means includes a first current controller to be used during a quick charge mode and second current controller to be used during a trickle charge mode.

6. A battery charging apparatus as cited in claim 5, wherein said charging current to said chargeable battery by said second current controller is in a range of about 1/10th to about 1/50th of the charging current to said chargeable battery by said first current controller.

7. A battery charging apparatus as cited in claim 1, wherein said charging condition detecting means includes battery voltage detecting means for detecting battery voltage and battery temperature detecting means for detecting battery temperature.

8. A battery charging apparatus as cited in claim 1, wherein said charging controller means includes a charging timer which determines charging time after said rechargeable battery has fully charged.

9. A battery charging apparatus as cited in claim 1, wherein said pulse width is calculated based on characteristic data of said chargeable battery stored in said charging controller means.

10. A battery charging apparatus for charging a chargeable battery, comprising:

means for charging a chargeable battery in at least one of a plurality of charging modes, including a normal charging mode, a quick charging mode, and a discharging responsive mode, said charging means including a dc power source for generating a charging current;

charging condition detecting means for detecting whether said chargeable battery is fully charged and whether said chargeable battery has begun to self-discharge;

charging controller means connected to said charging means and responsive to said charging condition detecting means for supplying a pulse to said charging means having a predetermined pulse width and interval according to at least one of said modes of charging, said pulse width and interval being related to a rate of discharge characteristic of said chargeable battery when said charging means is operating in said discharging responsive mode.

11. A battery charging apparatus as set forth in claim 10, wherein said charging condition detecting means further detects a temperature of said chargeable battery and provides a signal representative of said battery temperature to said charging controller means.

12. A battery charging apparatus as set forth in claim 10 wherein said charging condition detecting means include passive elements for determining when said chargeable battery has begun to discharge by detecting a change of a charging voltage between a time at which the battery is fully charged and a time at which discharge starts.

13. A battery charging apparatus as set forth in claim 12, wherein said charging controller means further includes a timing means for controlling a duration of application of said pulse.

14. A battery charging apparatus as set forth in claim 10 wherein said pulse is intermittently supplied to said chargeable battery when said means for charging operates in said discharging mode.

15. A battery charging apparatus as set forth in claim 10, wherein said pulse width is calculated based on characteristic data of said chargeable battery stored in said charging controller means.

16. A battery charging apparatus for charging a chargeable battery, comprising:

means for charging a chargeable battery in at least one of a plurality of charging modes, including a normal charging mode, a quick charging mode, and a discharging responsive mode, said charging means including a dc power source for generating s charging current;

charging condition detecting means for detecting whether said chargeable battery is fully charged and whether said chargeable battery has begun to self-discharge;

charging controller means connected to said charging means and responsive to said charging condition detecting means for supplying a pulse to said charging means having a predetermined pulse width and interval according to at least one of said modes of charging, said pulse width and interval being related to a rate of discharge characteristic of said chargeable battery when said charging means is operating in said discharging responsive mode;

wherein said charging condition detecting means include passive elements for determining when said chargeable battery has begun to discharge by detecting a change of a charging voltage between a time at which the battery is fully charged and a time at which discharge starts;

wherein said pulse width is calculated based on characteristic data of said chargeable battery stored in said charging controller means.