Patent ID: 8643342
Filing Date: 2014-02-04
Classification: H02J

Abstract:
1. A battery cell charging system, including a charger and a controller, for charging a lithium ion battery cell, the battery cell charging system comprising: a circuit for charging the battery cell using an adjustable voltage charging-profile to apply a charging voltage and a charging current to the battery cell wherein said adjustable voltage charging-profile includes: a first charging stage with a constant first stage charging current and an increasing battery cell voltage with said first stage charging current provided until said first stage charging voltage is about equal to a first stage complete voltage less than a maximum battery cell voltage; a second ramped charging stage, said second ramped charging stage including both an increasing ramped voltage and a decreasing ramped iBat current for the battery cell for the voltage charging range of said first stage complete voltage to about said maximum battery cell voltage, the ramped iBat current starting to decrease at the constant first stage charging current, wherein said second ramped charging stage has a slope responsive to an imaginary resistance R Bad established for the battery cell; and a third charging stage with a constant third stage charging voltage about equal to said maximum battery cell voltage and a decreasing third stage charging current with said third stage charging voltage provided until said third stage charging current reaches a desired charge complete level.