Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Commissariat a L'energie Atomique

Institut Polytechnique De Grenoble

Christine Lefrou

Rémy Mingant

Sébastien Martinet

Matthieu Le Prado

Yvan Reynier

Mathieu Baicry

Laure-Line Rouve

Fathia Karoui

Elisabeth Lemaire

A device for measuring an electric field in a conducting medium comprises: two electrodes separated by a volume of an insulating medium; a device for measuring current coupled to said electrodes; and adjustment elements making it possible to vary a quantity on which the electrical conductivity of the field measuring device depends.

Calibration of a device for measuring an electric field in a conducting medium

The method for determining the state of charge of a battery includes measurement of an electric parameter of the battery during a charging or discharging phase of the battery followed by placing the battery in open circuit during a rest period. During the rest period, at least two values of the voltage at the battery terminals are measured. An indicator is then calculated according to the electric parameter and to values of the voltage measured during the rest period, and the state of charge corresponding to this indicator is then determined by means of a calibration curve representative of the variations of the indicator as a function of the state of charge of the battery.

Method for determining the state of charge of a battery in charging or discharging phase

The method for determining the state of charge of a battery can be used during charging or discharging of the battery at constant current. It comprises placing the battery in open circuit during a recovery period until the voltage at the terminals of said battery stabilizes at a voltage plateau. Then a constant test voltage is applied to the battery terminals during a preset test period. The state of charge of the battery corresponds to the current measured at the end of the test period by means of a previously obtained calibration curve.

Method for determining the state of charge of a battery in charging or discharging phase at constant current

The management method comprises a charging phase and may comprise an optional prior phase of estimating the state of charge of the battery. Comparison of the absolute value of the slope of the voltage at the battery terminals with a full-charge threshold at the end of each period, when a pulsed current is applied, is used as end-of-charging criterion in the charging phase and/or as full-charge criterion in the phase of estimating the state of charge. The charging phase by pulsed current is interrupted when the slope reaches the full-charge threshold. This same comparison constitutes the criterion for estimating the necessity for going to a charging step after the prior phase of estimating the state of charge of the battery.

Method for managing charging of a rechargeable battery

Growing community of inventors

Grenoble, France

Christine Lefrou