CONTROL CIRCUITRY FOR TERMINATION OF RAPID BATTERY CHARGING

• US 3,622,857 A
• Filed: 01/30/1970
• Issued: 11/23/1971
• Est. Priority Date: 01/30/1970
• Status: Expired due to Term

• Current Assignee: Indar K. Sethi
• Original Assignee: Indar K. Sethi
• Inventors: Sethi, Indar K.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Gunther, John M.
• Application Number:
  US05/007,014
• Time in Patent Office: 662 Days
• Field of Search: 320/5,10,14,20,22-24,30,31,37-40,53,50,DIG.2 323/115
• US Class Current: 320/130
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process

Abstract

A battery is charged in a very short period of time, for example less than fifteen minutes, by alternately applying charging current pulses during a charge interval and applying a discharge path during a discharge interval as the charge on the battery progresses. The discharge path is applied in response to a signal that is an integral function preferably of the battery terminal voltage. Means are provided in the rapid battery charging circuitry for precluding the application of the discharge path while charge current pulses are being applied to the battery. The rapid charging of the battery is terminated with the possibility of the application of a trickle charge thereafter by circuitry that is responsive to a predetermined battery terminal voltage. The rapid battery charging circuitry also includes means for making the rapid charge terminating circuitry sensitive only to the battery terminal voltage while there are no charge current pulses being applied to the battery.

Claims

1. A rapid battery charging circuit comprising transmission means operable to transmit direct current pulses to a battery through a continuously operable electrical connection;

a discharge path inCluding an active element having a control terminal for applying the discharge path; and

a discharge means for periodically electrically applying said discharge path across said battery without interrupting said electrical connection between said battery and said transmission means, said discharge means including a series voltage divider combination of four impedance elements connected across said battery;

a capacitor connected across three of said impedance elements, with one side of the capacitor connected to the negative terminal of said battery;

a series combination of a silicon-controlled rectifier and a resistor connected in parallel with said capacitor, with the resistor connected in the cathode circuit of the siliconcontrolled rectifier;

means for connecting the gate of the silicon-controlled rectifier to the middle junction of the four impedance elements;

a source of voltage of opposite polarity and of the same phase as the direct current pulses applied to said battery, and means for connecting said source to the junction of the two impedance elements between the gate of said siliconcontrolled rectifier and the terminal of the battery to which one side of the capacitor is connected; and

means for connecting the cathode of said silicon-controlled rectifier to the control terminal of said active element.

2. A rapid battery charging circuit comprising first source means for supplying direct current pulses to a battery when the voltage level of said pulses exceeds the terminal voltage of said battery;

a discharge path;

means for developing a first battery function-responsive control signal;

second source means for supplying a second control signal that opposes said first control signal at least during the time the voltage level of said pulses exceeds the terminal voltage of said battery, and circuit means responsive to said control signals for applying said discharge path across said battery.

3. The battery charging circuit of claim 2 wherein the first control signal-developing means includes capacitor means for integrating a current related to battery terminal voltage with respect to time.

4. The battery charging circuit of claim 2 including means operable in response to the attainment of a predetermined battery terminal voltage for reducing the current applied from said first source to said battery.

5. The battery charging circuit of claim 4 including circuit means responsive to said second source for initially inhibiting said reducing means during the time the voltage level of said pulses exceeds the terminal voltage of said battery.

6. A circuit for rapid charging a battery comprising:

a source of alternating current voltage;

a transformer having a primary connected to said source and a center-tapped secondary and a pair of controllable switches connected to opposite ends of said secondary and poled to provide fullwave rectification;

means for connecting the direct current pulses at the output of the switches to a battery to be charged;

means for periodically discharging said battery as charge progresses;

said discharging means operable in response to a battery function;

a path around at least one of said switches for providing trickle charge current to said battery;

means for inhibiting the pair of switches operable in response to the attainment of a predetermined battery voltage;

second fullwave rectification means connected to opposite ends of said secondary for producing a voltage of opposite polarity and of the same phase as the fullwave output from said controllable switches; and

means for coupling at least a portion of the voltage at the output of said second fullwave rectification means to said discharging means to make it inoperative while charge current is flowing through said pair of controllable switches.