Patent ID: 7508167
Filing Date: 2009-03-24
Classification: H01M,H02J,Y02E

Abstract:
1. A battery charger, comprising: a housing; at least three terminals including a positive terminal, a negative terminal, and a sense terminal to electrically connect to a power tool battery pack supported by the housing, the battery pack including a plurality of lithium-based battery cells, each battery cell of the plurality of battery cells having an individual state of charge; and a controller operable to supply a charging current to the battery pack through at least one of the positive terminal and the negative terminal, the controller being operable to control the charging current being supplied to the battery pack based at least in part on the individual state of charge of at least one battery cell, wherein each battery cell of the plurality of battery cells is individually tapped such that the controller is operable to monitor the respective individual state of charge thereof via the sense terminal.