Lithium battery pack and system for charging the same

Abstract

A lithium battery pack according to the present invention has inherent information stored therein, which may include a nominal voltage, maximal voltage of the cells, range of temperature etc. A charging control signal is determined by a charging controller based on an identified state of the cells and the inherent information, and is transmitted to an electrical charging device. A controlled module in the charging device receives the charging control signal through and adjusts an output current to an accurate charging voltage for the current state of the battery pack.

We claim: 
     
         1 . An electrical charging system comprising:
 a battery pack comprising:
 a housing; 
 a plurality of lithium-based battery cells each having an individual state of charge; 
 a charging controller comprising a single unit disposed inside the battery pack and operable to monitor the individual state of charge of at least one of the battery cells and to generate a transmittable charging control signal representative of the individual state of charge of the at least one battery cell; and 
 at least one terminal operatively coupled to at least one of the battery cells; and 
   an electrical charging device being operable coupleable to the battery pack to supply power to the battery pack, the electrical charging device comprising:
 a first control terminal operably coupleable to the charging controller for receiving the charging control signal from the charging controller; 
 at least one voltage output terminal operably coupleable to the battery pack terminal; and 
 a controlled module, wherein the controlled module controls the output of a current with a charging voltage based on the received charging control signal received from the battery pack. 
   
     
     
         2 . An electrical charging system as recited in  claim 1 , wherein the electrical charging device is a power adapter. 
     
     
         3 . An electrical charging system as recited in  claim 1 , wherein the electrical charging device further comprises an AC to DC converter, and the voltage output terminal of the electrical charging device outputs a DC voltage. 
     
     
         4 . An electrical charging system as recited in  claim 1 , wherein the charging control signal is one of a voltage signal or a current signal. 
     
     
         5 . A lithium battery pack for a power tool comprising:
 a housing;   a plurality of lithium-based battery cells each having an individual state of charge;   a charging controller consisting of a single unit disposed inside the battery pack and operable to monitor the individual state of charge of at least one battery cell, the charging controller operable to generate a control signal determined by the individual state of charge of the at least one battery cell and inherent information stored therein; and   at least one terminal electrically connectable to a corresponding terminal of a power adapter, wherein the power adapter includes a controlled module directly coupleable to the charging controller to receive the control signal and supply a current with accurate charging voltage to battery packs based upon the received control signal.   
     
     
         6 . A lithium battery pack as recited in  claim 5 , wherein the power adapter has a first control terminal and the battery pack has a second control terminal, the first control terminal being operably coupled with the second control terminal and wherein the charging controller transmits a control signal to the controlled module through the first and the second control terminals. 
     
     
         7 . A lithium battery pack as recited in  claim 5 , wherein the power adapter has a receiver and the battery pack has transmitter and wherein the charging controller transmits a control signal to the controlled module through the transmitter and the controlled module receives the transmitted control signal through the receiver. 
     
     
         8 . A lithium battery pack as recited in  claim 5 , wherein the control signal comprises a charging parameter determined and transmitted to the controlled module by the charging controller based on the state of the plurality of battery cells and on information stored in the battery pack. 
     
     
         9 . A lithium battery pack as recited in  claim 8 , wherein the charging controller includes a sampling circuit for collecting the charging parameter, a battery protection circuit, and a matching network for outputting the control signal to the controlled module. 
     
     
         10 . A lithium battery pack as recited in  claim 5 , wherein the charging controller is operable to monitor the state of each of the plurality of battery cells. 
     
     
         11 . A lithium battery pack as recited in  claim 5 , wherein the inherent information comprises at least one of a nominal voltage of the battery cells, a maximal voltage of the battery cells, or a range of an operable temperature.