Method for balancing cells or groups of cells in a battery pack

• US 7,279,867 B2
• Filed: 12/02/2005
• Issued: 10/09/2007
• Est. Priority Date: 12/02/2005
• Status: Active Grant

• Current Assignee: Southwest Electronic Energy Corporation (Ultralife Corporation)
• Original Assignee: Southwest Electronic Energy Corporation (Ultralife Corporation)
• Inventors: White, David Allen, Benckenstein, Claude Leonard Jr.
• Primary Examiner(s): Easthom; Karl
• Assistant Examiner(s): Fantu; Yalkew
• Application Number:
  US11/293,432
• Publication Number:
  US 20070126399A1
• Time in Patent Office: 676 Days
• Field of Search: 320/119, 320/112, 320/116
• US Class Current: 320/119
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits

Abstract

A method for balancing cells or groups of cells connected in parallel and in series for a battery pack by providing a continuously balanced state of charge while in a discharge phase, a charge phase, a quiescent phase, a storage phase, or combinations of these phases.

Claims

1. 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.

2. The method of claim 1, further comprising the step of using a configuration table to customize the balancing of the state of charge for the individual cells or groups of individual cells, or combinations thereof.

3. The method of claim 1, further comprising the step of connecting the plurality or individual cells or groups of individual cells together in series to form at least one battery pack system.

4. The method of claim 1, further comprising the step of preventing excessive voltage from developing across the individual cell or groups of individual cells.

5. The method of claim 1, wherein the step of removing a portion of the charge For at least one individual cell or at least one group of individual cells until the balance state uses a disconnect circuit and a diode.