Method and apparatus for conditioning of nickel-cadmium batteries

• US 4,084,124 A
• Filed: 11/24/1976
• Issued: 04/11/1978
• Est. Priority Date: 11/24/1976
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Kapustka, Robert E.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US05/744,573
• Time in Patent Office: 503 Days
• Field of Search: 320/2, 320/9, 320/21, 320/31, 320/35, 320/39, 320/40, 320/48, 320/14, 320/15, 320/13, 320/32
• US Class Current: 320/131
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02M 3/3372 of the parallel type
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method and apparatus for reconditioning batteries utilizing a DC-DC converter. During a discharge of the batteries, each cell is monitored by the converter. When the voltage of a cell decreases to a predetermined level, a converter will assume the load of this cell and inhibit the voltage from reaching zero, thereby preventing voltage reversal of that cell.

Claims

1. A method for reconditioning a battery, having a plurality of cells, connected to an energy source comprising the steps of:

connecting across each cell a means for assuming the load of each cell when the voltage of each cell is reduced to a predetermined value;

removing the battery from the energy source;

placing a load across the battery;

allowing the cells of the battery to discharge until all of the cells have reached said predetermined value;

removing said load from across the battery; and

recharging the battery.

2. A method for reconditioning a battery according to claim 1 wherein a DC-DC converter is utilized in said connecting step.

3. A method for reconditioning the battery according to claim 2 further including the step of monitoring the input current of the DC-DC converter to properly determine the correct time to remove the battery from its energy source for initiating the reconditioning process.

4. A method for reconditioning a battery, having a plurality of cells, connected to an energy source comprising the steps of:

connecting across each cell a means for assuming the load of each cell when the voltage of each cell is reduced to a predetermined value;

removing the battery from the energy source;

placing a load across the battery;

allowing the cells of the battery to discharge for a predetermined period of time;

removing said load from across the battery; and

recharging the battery.

5. A method for reconditioning a battery according to claim 4 wherein a DC-DC converter is utilized in said connecting step.

6. A method for reconditioning a battery according to claim 5 further including the steps of monitoring the input current of the DC-DC converter to properly determine the correct time to remove the battery from its energy source for initiating the reconditioning process.

7. A device for reconditioning a battery having a plurality of cells comprising:

monitoring means containing a plurality of outputs, one output placed in parallel with a single cell of the battery, for sensing the voltage of each of the cells;

a control relay placed across all of the cells of the battery;

a load resistor placed in series with said relay whereby each of the outputs of said monitoring means senses the voltage of each cell and if the voltage of each cell reaches a predetermined value, said monitoring means assumes the load thus preventing the voltage in each cell from becoming zero.

8. A device for reconditioning a battery according to claim 7 wherein said monitoring means is a DC-DC converter.

9. A device for reconditioning a battery according to claim 7 further including a means for sensing the input current of said monitoring means.

10. A device for reconditioning a battery according to claim 7 further including a transformer for converting the input voltage of said monitoring means to the level and number of outputs required for the battery.

11. A device according to claim 7 wherein the battery is of the nickel-cadmium type.