Patent ID: 8089249

Claim:
A battery management system comprising: a switch array for selecting a battery module from a plurality of battery modules in a battery pack based upon a conduction state of said switch array, wherein each battery module of said battery modules comprises a plurality of cells; and a first controller coupled to said switch array and for receiving measurement information of cells in the selected battery module through said switch array; and a second controller coupled to said switch array and said first controller and for providing a control signal to control said conduction state of said switch array, determining a balance level of said selected battery module based upon said measurement information, and allocating a time segment to said selected battery module based upon said balance level, wherein a duration of said time segment is determined according to said balance level, wherein said first controller further controls a balance circuit coupled to said battery pack to balance said selected battery module during said time segment if said selected battery module is identified as an unbalanced battery module by said second controller.