Process for monitoring the residual charge and capacity of a battery

US6329823A · kind A · utility

Assignee

• Daimlerchrysler AG · US

Inventors

• Alf Blessing · Bad Boll, DE
• Hans-Peter Schoner · Seeheim-Jugenheim, DE

Key dates

• Filing date: Dec 15, 2000
• Grant date: Dec 11, 2001
• Expiry date: Dec 15, 2020

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/3842
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Process for monitoring the residual charge and the capacity of a battery, where at least two voltage-current measurements have been carried out on the load-carrying battery. The current load of the battery selected here should be greater than 30% of the nominal capacity per hour, e.g. for a 100 Ah battery, at least 30 amperes. The initial voltage-current measurement is taken at an initial time for an initial load condition of the battery. A second voltage-current measurement is carried out at a second time for a second load condition of the battery. It is essential here that the load condition of the battery has changed because of the current that has been drawn. The current-voltage measurements produce an initial measuring point and a second measuring point. The two measuring points set an interpolation line and determine the point of intersection with a limiting voltage level (U.sub.Gr). This point of intersection is marked by a so-called limiting current (I.sub.Gr). The limiting voltage level is decided from the minimum voltage required by the connected consumers in order for them to operate fault-free. The limiting voltage level is therefore stipulated for the technical layout …