Patent ID: 6433513
Filing Date: 2002-08-13
Classification: G01R,H02J,Y02E

Abstract:
A method for determining a service life of a secondary battery subjected to repeated charging/discharging cycles; comprising the steps of:storing, in a memory device, pre-measured values of an index related to decrements in service life of the battery, which is fully charged after each discharge event during a charging/discharging cycle, to correspond to discharged amounts produced during charging/discharging cycles experienced by the battery during the respective charging/discharging cycles; computing a discharged amount after each charging/discharging cycle; obtaining an index to correspond to the discharged amount from said memory device; computing a service life remaining after the current cycle of charging/discharging according to a maximum service life of the battery and the values of the index obtained in individual charging/discharging cycles, including the current charging/discharging cycle; and determining whether or not the remaining service life computed is less than a pre-determined reference value, and deeming that the battery has reached an end of the service life when the computed value is less than the reference value.