Charging apparatus for secondary elements for controlling the charging end in response to the inflection point of the terminal voltage of the secondary element

摘要

A control section detects terminal voltage of a battery periodically and stores it in a memory, then calculates the most recent gradient and average gradient of a charging curve from the storage contents. When the most recent gradient becomes greater than the average gradient by a predetermined value or more, the control section judges it to be the last stage of the charging. After this, the control section compares the most recent terminal voltage with the preceding terminal voltage which are detected and stored in sequence. When they become equal to each other, the control section turns off a charge switch for terminating the charging. Thus, a rise in the terminal voltage at the last stage of the charging is detected securely and the subsequent peak is detected accurately. IMAGE