BATTERY CHARGING SYSTEM USING A COULOMETER AS A LOGIC DEVICE

• US 3,652,917 A
• Filed: 02/24/1970
• Issued: 03/28/1972
• Est. Priority Date: 02/24/1970
• Status: Expired due to Term

• Current Assignee: Carl E. Biggs
• Original Assignee: Carl E. Biggs
• Inventors: Biggs, Carl E.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/013,624
• Time in Patent Office: 763 Days
• Field of Search: 324/94,29.5 320/39,40,45,DIG.1,35,36
• US Class Current: 320/128
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current

Abstract

A rechargeable storage battery power supply system in which a coulometer is used as a logic device to provide transition between high charge rate and low charge rate. During battery discharge, the coulometer may act as a logic device to disconnect the load from the battery after a predetermined time integral of current is drawn from the battery. The charging current is applied in reverse direction through the coulometer and when the coulometer reaches its high impedance state in the charging direction a trickle charge is bypassed to the battery. The trickle charge control includes a thermistor responsive to battery temperature. An additional circuit is provided which acts to provide constant voltage float charge after the battery has been fully charged, and which additional circuit also uses the coulometer as a logic element.

Claims

1. A rechargeable storage battery power supply system comprising, in combination, a storage battery and a load through which said battery is adapted to discharge, a coulometer in series with said battery and the load, means for disconnecting said battery from said load in response to an abrupt electrode potential appearing across said coulometer indicating predetermined discharge of said battery, means for connecting a charging current to said battery through said coulometer, and means continuously connected in parallel across said coulometer for bypassing a trickle current charge therearound when an abrupt electrode potential appears across the coulometer indicating predetermined charging of the battery.

2. In a rechargeable storage battery power supply system including a battery adapted to discharge through a load, in combination, coulometer means for reverting to a state of high impedance to a battery charging current therethrough in response to predetermined charging of said battery, means for charging said battery through said coulometer means, current sampling means in series with said means for charging and said coulometer means, and a low charge rate voltage clamp Connected in series with said current sampling means across said coulometer means when said coulometer means reverts to said high impedance state.

3. In the power supply system as defined in claim 2 wherein said low charge rate voltage clamp includes a thermistor sensitive to battery temperature to modify the low charge rate.

4. In the power supply system as defined in claim 3, including a charging current regulator connected to said current sampling means a high charge rate control resistor connected in parallel with said current sampling means and said coulometer means, and a control amplifier for said regulator connected to said high charge rate control resistor.

5. In the power supply system as defined in claim 2, including a charging current regulator connected to said current sampling means, a high charge rate control resistor connected in parallel with said current sampling means and said coulometer means, and a control amplifier for said regulator connected to said high charge rate control resistor.

6. A power supply system comprising, in combination, a storage battery, an electrical load, a charging current source for said battery, a coulometer which reversibly produces an abrupt transition from substantially zero potential to a finite potential thereacross in response to passage of a predetermined quantity of current therethrough, switch means for connecting said coulometer and said load in series across said battery, means connected across said coulometer for disabling said switch means in response to appearance of said finite potential across the coulometer when said battery is discharging, said charging current source and said coulometer being in series across said battery to recharge the battery, and means connected across said coulometer means for passing a limited charging current to said battery in response to appearance of said finite potential across the coulometer when the battery is being charge.

7. The power supply system as defined in claim 6, wherein the last means includes a thermistor associated with said battery to limit the charging current in accord with the temperature of the battery.

8. In a rechargeable storage battery power supply system including a battery adapted to discharge through a load, in combination, a coulometer which reversibly produces an abrupt transition from substantially zero potential to a finite potential thereacross in response to passage of a predetermined quantity of current therethrough, switch means for connecting said coulometer in series with a load across said battery, means for passing a controlled high charging rate current to said battery through said coulometer, and means for passing a limited charging current to said battery in response to appearance of said finite potential across the coulometer when the battery is being charged, said means for passing a high charging rate current including a control amplifier, said means for passing a limited charging current comprising a constant voltage float device and including a voltage reference and differential amplifier means for controlling said control amplifier to maintain a constant voltage float charge across said battery.

9. The power supply system as defined in claim 8 wherein the means for passing a limited charging current also includes a thermistor associated with said battery to limit the charging current in accord with the temperature of the battery.

10. The power supply system as defined in claim 8, wherein said means for passing a limited charging current further comprises a thermistor associated with said battery to limit the charging current in accord with the temperature of the battery.