Patent ID: 7279867

Claim:
A method for balancing a battery pack having a plurality of individual cells or groups of individual cells connected in series, or connected in parallel and then in series, the method comprising the steps of: a. monitoring and measuring parameters for a plurality of individual cells connected in parallel or groups of individual cells connected in parallel and then some of the plurality or groups are connected in series, to determine a state of charge for the individual cells connected in parallel or the individual groups of cells connected in parallel and then in series wherein the monitoring and measuring step further comprises measuring a temperature of the cells or the groups of cells; measuring current of the cells or the groups of cells; and measuring cell voltages of the cells or the groups of cells, and b. removing at least a portion of a charge from the plurality of individual cells connected in parallel or groups of individual cells connected in parallel and then in series to achieve a balanced state of charge for the plurality of individual cells or groups of individual cells while in a discharge phase, a charge phase, a quiescent phase, and a storage phase, further comprising using a digital controller to execute computer instructions to balance the cells, wherein the computer instructions instruct a processor connected to the plurality of cells or groups of cells to execute the steps comprising: monitoring and measuring the state of charge for the plurality of cells or groups of cells; activating at least one disconnect circuit between the plurality of cells or groups of cells; when the monitoring and measuring values extend beyond preset limits; and activating at least one balancing circuit to manage the removal of at least a portion of a charge from the plurality of cells or groups of cells to achieve balance.