Process and apparatus for charging a battery

• US 5,621,297 A
• Filed: 01/28/1994
• Issued: 04/15/1997
• Est. Priority Date: 01/27/1992
• Status: Expired due to Term

• Current Assignee: ZincFive, Inc.
• Original Assignee: Robert S. Feldstein
• Inventors: Feldstein, Robert S.
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US08/188,444
• Time in Patent Office: 1,173 Days
• Field of Search: 320/3, 320/4, 320/5, 320/8, 320/9, 320/21, 320/39, 320/40
• US Class Current: 320/129
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A process for charging a cell is disclosed. In this process, a discharged cell is connected to a charger. Discharge pulses are periodically withdrawn from the cell. Charging pulses are provided by the charger, and they are delivered to the cell only when the cell voltage at the end of the discharge interval is less than a specified reference voltage.

Claims

1. A process for charging a zinc-manganese dioxide primary cell, comprising the steps of:

(a) connecting a discharged zinc-manganese dioxide primary cell to a battery charger, wherein said battery charger is comprised of means for comparing the voltage of said cell at the termination of a discharge period of time with a specified reference voltage, means for periodically discharging said cell, and means for periodically producing direct current charging pulses with an average value which does not exceed an initial capacity of said cell to accept charge;

(b) periodically withdrawing discharging pulses of direct current from said cell during said discharge period of time;

(c) delivering said direct current charging pulses to said cell whenever said voltage of said cell at the end of said discharge period of time is less than said specified reference voltage; and

(d) preventing the delivery of said direct current charging pulses to said cell whenever said voltage of said cell at the end of said discharge period of time is greater than said specified reference voltage.

2. The process as recited in claim 1 wherein said step of periodically withdrawing includes:

said discharging pulses of direct current having a duration of from about 5 to about 35 percent of the duration of said direct current charging pulses; and

said discharging pulses of direct current having a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

3. The process as recited in claim 1 where said means for periodically producing direct current charging pulses produces pulses with a duration of at least about 1 millisecond and an average value which does not exceed about 40 percent of said initial capacity of said cell to accept charge.

4. The process of claim 1 where said step of periodically withdrawing discharging pulses of direct current includes:

said discharging pulses having a duration of at least about 0.5 seconds; and

said discharging pulses of direct current having a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

5. The process of claim 1 further including the step of periodically withdrawing second discharging pulses of direct current from said cell during a second discharge period of time, wherein:

said second discharging pulses of direct current have a duration of at least 0.5 seconds; and

said second discharging pulses of direct current have a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

6. The process as recited in claim 1 wherein said zinc-manganese primary cell is an alkaline cell.

7. The process as recited in claim 1, wherein said specified reference voltage does not exceed about 1.7 volts.

8. A process for charging a cell, comprising the steps of:

(a) connecting a discharged cell to a battery charger, wherein said battery charger is comprised of means for comparing the voltage of said cell at the termination of a discharge period of time with a specified reference voltage, means for periodically discharging said cell, and means for periodically producing direct current charging pulses with an average value which does not exceed an initial capacity of the cell to accept charge;

(b) periodically withdrawing discharging pulses of direct current from said cell during said discharge period of time;

(c) delivering said direct current charging pulses to said cell whenever said voltage of said cell at the end of said discharge interval is less than said specified reference voltage; and

(d) preventing the delivery of said direct current charging pulses to said cell whenever said voltage of said cell and the end of said discharge interval is greater than said specified reference voltage.

9. The process as recited in claim 8 wherein said step of periodically withdrawing includes:

said discharging pulses of direct current having a duration of from about 5 to about 35 percent of the duration of said direct current charging pulses; and

said discharging pulses of direct current having a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

10. The process as recited in claim 8 where said means for periodically producing direct current charging pulses produces pulses with a duration of at least about 1 millisecond and an average value which does not exceed about 40 percent of said initial capacity of said cell to accept charge.

11. The process of claim 8 where said step of periodically withdrawing discharging pulses of direct current includes:

said discharging pulses having a duration of at least about 0.5 seconds; and

said discharging pulses of direct current having a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

12. The process as recited in claim 8 further including the step of periodically withdrawing second discharging pulses of direct current from said cell during a second discharge period of time, wherein:

said second discharging pulses of direct current have a duration of at least about 0.5 seconds; and

said second discharging pulses of direct current have a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

13. The process as recited in claim 8 wherein said cell is a rechargeable alkaline manganese cell.

14. The process as recited in claim 8 wherein said cell is a rechargeable lead acid cell.

15. A process for charging a nickel-cadmium cell, comprising the steps of:

(a) connecting a discharged nickel-cadmium cell to a battery charger, wherein said battery charger is comprised of means for comparing the voltage of said cell at the termination of a discharge interval with a specified reference voltage, means for periodically discharging said cell, and means for periodically producing direct high current charging pulses with an average value which does not exceed about twice an initial capacity of the cell;

(b) periodically withdrawing discharging pulses of direct current from said cell during a discharge period of time;

(c) delivering said direct current charging pulses to said cell whenever said voltage of said cell at the end of said discharge period of time is less than said specified reference voltage; and

(d) substituting a lower current pulse of from about 5 to about 30 percent of the current capacity of said cell for said high current pulse and delivering said lower current pulse to said cell whenever said voltage of said cell and the end of said discharge period of time is greater than said specified reference voltage.

16. The process as recited in claim 15 wherein said step of periodically withdrawing includes:

said discharging pulses of direct current having a duration of from about 5 to about 35 percent of the duration of said direct current charging pulses; and

said discharging pulses of direct current having a current value during discharge of from about 5 to about 15 percent of the average value of said direct current charging pulses.

17. The process as recited in claim 15 wherein said step of periodically withdrawing discharging pulses of direct current from said cell during said discharge period of time includes:

said discharging pulses have a duration of at least about 0.5 seconds; and

said discharging pulses of direct current have a current value during discharge of from about 5 to about 15 percent of the average value of said direct current charging pulses.

18. The process as recited in claim 15 where said means for periodically producing direct current charging pulses produces pulses with a duration of at least about 1 millisecond and an average value which does not exceed about 40 percent of said initial capacity of said cell to accept charge.

19. The process of claim 15 where said step of periodically withdrawing discharging pulses of direct current includes:

said discharging pulses having a duration of at least about 0.5 seconds; and

said discharging pulses of direct current having a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

20. The process of claim 15 further including the step of periodically withdrawing second discharging pulses of direct current from said cell during a second discharge period of time, wherein:

said second discharging pulses of direct current have a duration of at least about 0.5 seconds; and

said second discharging pulses of direct current have a current value during discharge of from about 10 to about 25 percent of the average current value of said direct current charging pulses.

21. A battery charger for charging a primary cell, said battery charger comprising:

means for comparing the voltage of a primary cell at the termination of a discharge interval with a specified reference voltage;

means for periodically discharging said cell;

means for periodically producing direct current charging pulses with an average value which does not exceed an initial capacity of said primary cell to accept charge;

means for periodically withdrawing discharging pulses of direct current from said primary cell during a discharge period of time;

means for delivering said direct current charging pulses to said primary cell whenever said voltage of said primary cell at the end of said discharge period of time is less than said specified reference voltage; and

means for preventing the delivery of said direct current charging pulses to said cell whenever said voltage of said cell and the end of said discharge period of time is greater than said specified reference voltage.

22. A battery charger of claim 21 further including means for withdrawing second discharging pulses of direct current from said cell during a second discharge period of time wherein:

said second discharging pulses of direct current have a duration of at least about 0.5 seconds; and

said second discharging pulses of direct current have a current value during discharge of from about 10 to about 25 percent of the average value of said direct current charging pulses.

23. The battery charger of claim 21 further including means for substituting a lower current pulse of from about 5 to about 30 percent of the current capacity of said cell for said high current pulse and delivering said lower current pulse to said cell whenever said voltage of said cell and the end of said discharge period of time is greater than said specified reference voltage.