摘要 |
As a substantially constant charge current is applied to a battery, the voltage is periodically measured and the slope of the voltage characteristic is calculated. The minimum slope of the bottom peak of the slope profile is dynamically identified and, as appropriate, updated and stored. With each identification and update of the minimum slope, a trigger threshold between the minimum slope and top peak is defined, and then stored, by adding a trigger value to the minimum slope. A termination threshold or value between the minimum slope and the trigger threshold may also be calculated and stored with each such identification and update of the minimum slope. When the calculated slope, increasing from the bottom peak, reaches the trigger threshold, the method is armed-as by setting a trigger threshold flag-so that when the calculated slope thereafter once again passes through the trigger threshold and then reaches the termination threshold, full-current charging of the battery is terminated. The termination threshold-which identifies the substantially fully-charged state of the battery-may, in some forms of the invention, be preset to equal the minimum slope value. Premature termination resulting from a high impedance spike or inflection point occurring in the voltage profile when charging current is initially applied to the battery may be avoided by gradually increasing the applied charging current at the beginning of the charging process.
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