Patent ID: 7598709
Filing Date: 2009-10-06
Classification: H02J,Y02B,Y02E

Abstract:
1. A method for fast charging a lithium ion battery cell having a maximum recommended battery cell voltage, the method comprising: (a) providing a charging current during a constant current mode of operation during which a first charging voltage and a constant current are applied to said battery cell; (b) periodically measuring the battery cell open circuit voltage to determine if it has reached a predetermined value; (c) maintaining said constant current mode of operation until said battery cell open circuit voltage reaches a predetermined value less than said maximum recommended battery cell voltage; (d) switching to a constant voltage mode of operation when said open circuit battery cell voltage reaches said predetermined value, wherein in said constant voltage mode of operation a constant second voltage is applied to said battery cell during said constant voltage mode of operation; (e) monitoring the charging current supplied to said battery cell during said constant voltage mode of operation; and (e) terminating charging when said charging current during said constant voltage mode of operation drops below a predetermined value.