METHOD AND APPARATUS FOR AUTOMATICALLY CONTROLLING THE FAST CHARGING OF RECHARGEABLE BATTERIES

• US 3,623,139 A
• Filed: 11/06/1969
• Issued: 11/23/1971
• Est. Priority Date: 11/06/1969
• Status: Expired due to Term

• Current Assignee: Gates Energy Products, Inc. (Schneider Electric SE)
• Original Assignee: Arthur F. Dickerson
• Inventors: Dickerson, Arthur F.
• Primary Examiner(s): Goldberg, Gerald
• Assistant Examiner(s): Gunther, John M.
• Application Number:
  US04/874,447
• Time in Patent Office: 747 Days
• Field of Search: 320/17,19,15,20,22-24,35,36,39,40,14,46,DIG.1,DIG.2
• US Class Current: 320/116
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02M 5/12 for conversion of voltage or current amplitude only
• CPC Class Codes: H02M 7/12 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: Y10S 320/28 Regulating transformer, e.g. high leakage, ferro-resonant

Abstract

A method and apparatus for automatically controlling the fast recharging of a storage battery pack consisting of a number of cells (N). The cells are conditioned so that at least one of them is at a slightly higher charge state than the remaining cells (N1) before initiating a recharging process. All the cells (N) are connected to a source of charging current and a voltage level responsive circuit is connected across the at least one cell which is at a higher charge state in order to monitor the increasing voltage thereof. The cells (N) are initially charged with a high current until the voltage at the terminals of the cell with the higher charge state abruptly rises and thereby signals to the voltage level responsive circuit that the cell has achieved full charge. At this point, the voltage level responsive circuit causes a transformer tap changing and switching circuit to terminate the high-current fast-charging mode and to establish a low-current slow-charging mode.

Claims

1. A method for fast-charging a rechargeable battery including at least two cells comprising the steps of:

a. preconditioning the cells during the discharge period by connecting a first load means across all of said cells and a second load means across all but at least one of said cells so that at the commencement of the charging cycle at least one cell is at a slightly higher charge state than the remaining cells;

b. supplying a relatively high charging current at a single rate to all cells of the battery;

c. monitoring the voltage across said at least one cell;

d. terminating the high charging current and initiating a low charging current in response to an abrupt increase in terminal voltage across said at least one cell.

2. A circuit arrangement for the fast charging of rechargeable batteries consisting of at least two cells comprising:

a. means for preconditioning said cells during the discharge period so that at the commencement of the charging cycle at least one of said cells is at a higher charge state than the remaining cells comprising a first load means across all of said cells and a second load means across all but at least one of said cells;

b. means for supplying a relatively high charging current at a single rate to all cells of the battery;

c. means for monitoring the voltage across said at least one cell; and

d. means for terminating a fast-charge mode and initiating a low-current charge mode in response to an abrupt increase in terminal voltage across said at least one cell which is at a higher charge state than the remaining cells.

3. A circuit arrangement for the fast charging of rechargeable batteries according to claim 2 wherein said means for terminating a fast-charge mode and initiating a slow-charge mode comprises a voltage level responsive circuit connected across said at least one cell and a transformer tap-changing means operatively connected with said transformer means and controllable by said voltage level responsive means.

4. The circuit arrangement according to claim 2 wherein said rectifying means includes an SCR bridge, and said current-regulating means comprises a current sensor connected with a firing pulse generator connected to said SCR bridge, said firing pulse generator operative to vary the firing angle of the SCR'"'"''"'"'s within said SCR bridge so as to regulate the average current passing therethrough.

5. The circuit arrangement according to claim 3 wherein said voltage level responsive circuit comprises a transistor switch to actuate said transformer tap-changing means and a voltage divider means for presetting the voltage of the at least one cell which will actuate said transistor switch.

6. The circuit arrangement according to claim 5 wherein said voltage divider means includes a temperature-sensitive means for adjusting the preset value of voltage needed across the at least one cell to actuate said transistor switch in response to the temperature of said battery.

7. A method of charging and discharging a battery including at least two cells in a manner permitting fast charging thereof comprising the steps of:

a. preconditioning the cells by partially discharging all of the cells through a primary load and contemporaneously partially discharging all but one cell through a secondary load so that one cell is at a slightly higher charge state than the remaining cells before charging the battery;

b. charging the cells at a relatively high charging-current rate;

c. monitoring the voltage across the cell having the higher charge state;

d. terminating the high charging-current rate and initiating a low charging-current rate in response to an abrupt increase in terminal voltage across the at least one cell.