Method and apparatus for determining the state-of-charge of batteries particularly lithium batteries

US4725784A · kind A · utility

Assignee

• Ramot University Authority for Applied Research and Industrial Development, Ltd. · IL

Inventors

• Emanuel Peled · Even Yehuda, IL
• Herzel Yamin · Rehovot, IL
• Israel Reshef · Givatayim, IL
• David Kelrich · Ramat HaSharon, IL
• Shlomo Rozen · Wilmington, US

Key dates

• Filing date: Sep 10, 1984
• Grant date: Feb 16, 1988
• Expiry date: Sep 10, 2004

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/3835
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Method and apparatus for determining the state-of-charge of batteries, particularly lithium batteries, involves the steps of: (a) measuring the temperature of the battery; (b) loading the battery to produce a high discharge for a short period of time; (c) after a short rest period, measuring the open-circuit-voltage of the battery; and (d) determining from the measured temperature and open-circuit-voltage the residual state-of-charge of the battery. Preferably, the residual state-of-charge of the battery is determined by comparing the measured temperature and open-circuit-voltage with reference tables showing the state-of-charge at different temperatures and open-circuit-voltages for the respective battery.