Method for extending power duration for lithium ion batteries

• US 7,199,556 B1
• Filed: 12/02/2005
• Issued: 04/03/2007
• 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:
  US11/293,334
• Time in Patent Office: 487 Days
• Field of Search: 320/119, 320/112, 320/116, 320/128
• US Class Current: 320/119
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits

Abstract

A method for extending the power duration of lithium ion cells or groups of lithium ion cells connected in parallel and in series 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 extending power duration for individual lithium ion cells or groups of individual lithium ion cells connected in series, or connected in parallel and then in series, comprising the steps of:

a. monitoring and measuring parameters for a plurality of individual lithium ion cells connected in parallel or groups of individual lithium ion cells connected in parallel, wherein the plurality of individual lithium ion cells connected in parallel or groups of individual lithium ions cells connected in parallel are further connected in series, to determine a state of charge for the individual lithium ion cells connected in parallel or the groups of individual lithium ion cells connected in parallel;

b. removing at least a portion or a charge from the state of charge for at least one of the individual lithium ion cells connected in parallel or at least one of the groups of lithium ion cells connected in parallel to achieve a balanced state of charge for the plurality of individual lithium ion cells connected in series, or groups of lithium ion cells connected in series, 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 comprising the steps of;

monitoring and measuring the state of charge for the plurality or individual lithium ion cells or groups of individual lithium ion cells;

activating at least one disconnect circuit for safety between the plurality of individual lithium ion cells or groups of individual lithium ion cells; and

activating at least one balancing circuit to achieve balance between the plurality of individual lithium ion cells or groups of individual lithium ion cells.

2. The method of claim 1, wherein the monitoring and measuring further comprises measuring temperature of individual lithium ion cells or groups of individual lithium ion cells, measuring current of individual lithium ion cells or groups of individual lithium ion cells, measuring cell voltages of individual lithium ion cells or groups of individual lithium ion cells, or combinations thereof.

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

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

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

6. 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.