IMPEDANCE CONTROLLED BATTERY CHARGER AND METHOD OF CHARGING WITH MONITORING OF A.C. ANSWER SIGNAL

• US 3,816,807 A
• Filed: 07/18/1973
• Issued: 06/11/1974
• Est. Priority Date: 07/18/1973
• Status: Expired due to Term

• Current Assignee: Gates Energy Products, Inc. (Schneider Electric SE)
• Original Assignee: Dale F. Taylor
• Inventors: Taylor, Dale F.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/380,134
• Time in Patent Office: 328 Days
• Field of Search: 320/20,22,30,39,40,43,48 324/29.5 340/249
• US Class Current: 320/139
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery charger comprises a variable current DC power supply adapted to be connected across a secondary battery, an AC modulator connected to the DC power supply, a phase sensitive detector adapted for connection across the battery, AC voltage reference signal means connected to the phase sensitive detector, and means for monitoring the amplitudes of two different voltage components of the AC voltage appearing across the battery. An impedance controlled battery charger is described in which the monitoring means of the above type of battery charger are provided in the form of a feedback control connected from the output of the phase sensitive detector to the DC power supply automatically adjusting DC current to match current accepting capabilities of the battery. Methods of battery charging are also described.

Claims

1. A battery charger which comprises a variable current DC power supply adapted to be connected across a secondary battery, an AC modulator connected to the DC power supply, a phase sensitive detector adapted to be connected across the battery, AC voltage reference signal means connected to the phase sensitive detector, and means for monitoring the amplitudes of two different voltage components of the AC voltage appearing across the battery.

2. A battery charger as in claim 1, in which the monitoring means monitor two DC voltage signals from the phase detector which signals are proportional to the amplitudes of the in-phase and out-of-phase voltage components of the AC voltage appearing across the battery.

3. A battery charger as in claim 1, in which the AC voltage reference signal means is connected from the output of the AC modulator to the phase sensitive detector.

4. A battery charger as in claim 1, in which the AC voltage reference signal means is connected across a resistance in series with the battery at the output of the DC power supply and to the phase sensitive detector.

5. A battery charger as in claim 1, in which the monitoring means is a display device.

6. An impedance controlled battery charger as in claim 1, in which the monitoring means is a feedback control connected from the output of the phase sensitive detector to the DC power supply automatically adjusting DC current to match current accepting capabilities of the battery.

7. A method of charging a secondary battery which comprises applying a DC current across a battery to be charged, superimposing an AC current on the DC current, providing a voltage reference signal of known phase with respect to the AC current, measuring the amplitudes of two different AC voltage components from the battery output which voltage components differ by a constant and known phase angle, monitoring the AC voltage component amplitudes until changes occur indicating that current accepting capability of the battery has been exceeded, and adjusting the DC current input to the battery to maintain the difference in the AC voltage component amplitudes at that value corresponding to the limit of the battery'"'"''"'"'s current accepting capability.

8. A method of charging a secondary battery as in claim 7, in which the amplitudes are measured of two AC voltage components from the battery output which voltage components are 90* out-of-phase with each other, providing two DC voltage signals which are proportional to the amplitudes of the in-phase and out-of-phase voltage components measured across the terminals of the battery, and monitoring the two DC voltage signals until changes occur indicating that current accepting capability of the battery has been exceeded prior to adjusting the DC current input to the battery.

9. A method of charging as in claim 7, wherein the two AC voltage component amplitudes are monitored on a display device.

10. An impedance controlled method of charging as in claim 7, wherein the two AC voltage component amplitudes are monitored by a feedback control which adjusts automatically the DC current input to the battery to maintain the difference in the AC voltage component amplitudes at that value corresponding to the limit of the battery'"'"''"'"'s current accepting capability.