Method of charging a battery

• US 5,329,218 A
• Filed: 11/30/1992
• Issued: 07/12/1994
• Est. Priority Date: 05/28/1990
• Status: Expired due to Fees

• Current Assignee: Sten A.O. Rydborn
• Original Assignee: Sten A.O. Rydborn
• Inventors: Rydborn, Sten A. O.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US07/952,828
• Time in Patent Office: 589 Days
• Field of Search: 320/21, 320/32
• US Class Current: 320/139
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A method of regulating the charging of batteries containing a number of cells, for example NiCd cells. The battery is connected to a battery charger for impressing a current through the battery for charging thereof. Prior to the actual impression of current through the battery cells for raising their terminal voltage, the voltage drop caused by cables, connections, the inner resistances of the battery caused by the battery cells, etc., is established for a number of different brief current pulses. The value of the voltage drop established for each current pulse is stored in a memory, and currents of substantially the same magnitude as each respective current pulse are impressed successively through the battery, each one of a length of time such that the voltage measured across the battery corresponds to the maximum permitted terminal voltage of the battery, plus the voltage drop established and stored for the corresponding current pulse.

Claims

1. A method of charging a battery containing a number of cells, comprising connecting a battery to a battery charger;

passing a plurality of brief current pulses through the battery;

measuring the voltage drop due to cables, terminals, and the inner resistances of the battery formed by the battery cells, during the plurality of brief current pulses;

storing the value of the measured voltage drop established for each one of the current pulses in a memory; and

passing currents of substantially the same magnitude as each respective current pulse successively through the battery, each one of said last-named currents continuing for a length of time such that the voltage measured across the battery corresponds to the maximum permitted terminal voltage of the battery plus the established and stored voltage drop for the corresponding current pulse.

2. The method as claimed in claim 1, wherein the magnitude of the current pulses is successively reduced, and thereby also the magnitude of the corresponding currents which are impressed through the battery for raising its terminal voltage is successively reduced.

3. The method as claimed in any of claims 1 and 2, further comprising monitoring the current required for achieving said maximum permitted terminal voltage;

and discontinuing the currents through the battery when the monitored current increases instead of successively decreasing.