Abstract: An electricity power supply circuit for an external appliance whose consumption varies over time. The circuit comprises an electrochemical cell, a supercapacitor serving as a source of electricity for said appliance, and a chopper voltage converter between the cell and the supercapacitor, the converter serving to charge the supercapacitor at constant current while monitoring the voltage across the terminals thereof. The circuit is applicable to cellular radiotelephones.

Abstract: The present invention provides a method of charging a carbon-anode lithium storage cell, which method comprises a first step in which a constant current is imposed and during which the voltage across said storage cell is allowed to increase until it reaches a reference value, and then a second step in which said reference voltage is imposed and said current decreases. The method of the invention is characterized in that, at each instant, said reference voltage is equal to the sum of the end-of-charge voltage of the cell plus the product of the current multiplied by the ohmic resistance of the cell.

Abstract: A system for monitoring aging of a battery comprising a plurality of cells connected in series and able to be fully discharged comprises a discharger which discharges one of the previously charged cells at a time to an end of discharge value. The quantity of electricity supplied by each discharged cell during discharging is measured. The quantity of electricity supplied by at least one discharged cell is processed to detect excessive aging of the battery. Excessive aging of the battery results in a residual capacity which is less than a fraction of the nominal capacity of the battery.

Abstract: The state of charge of an electrochemical storage unit is measured by applying to the electrochemical storage unit (32), a voltage pulse which is less than its nominal voltage, so as to make the storage unit deliver a high discharge current for a short period of time. The level of the voltage pulse is chosen to cause a discharge current that varies monotonically and preferably approximately linearly as a function of the state of charge of the storage unit, so that the state of charge can be unambiguously estimated by measuring the discharge current.

Abstract: The invention relates to a circuit for measuring the state of charge of an electrochemical cell that includes a parasitic resistance. The circuit comprises:means for subjecting the electrochemical cell to a reference voltage less than its nominal voltage, so as to cause it to deliver a discharge current;means for measuring the discharge current and providing an indication of the state of charge of the electrochemical cell; andcorrection means for correcting the reference voltage as a function of the discharge current, the correction means providing a corrected reference voltage that compensates for the parasitic resistance.