System and method for balancing energy storage devices

• US 9,647,467 B2
• Filed: 10/19/2010
• Issued: 05/09/2017
• Est. Priority Date: 10/19/2009
• Status: Expired due to Fees

• Current Assignee: 4ESYS NV
• Original Assignee: 4ESYS NV
• Inventors: Verhaeven, Eric, Van Den Keybus, Jeroen, Vidael, Rudolf, Coosemans, Johan
• Primary Examiner(s): Kaplan, Hal
• Assistant Examiner(s): Ortiz, Elim
• Application Number:
  US13/502,256
• Publication Number:
  US 20120235494A1
• Time in Patent Office: 2,394 Days
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A system for balancing a series connection of energy storage devices having: an intermediate storage element coupled between a pair of sections of one or a number of adjacent energy storage devices of a series connection of energy storage devices, sections each having a more positive terminal (A) at one end and a more negative terminal (B) at its other end; and a switching device for switching sequentially between coupling terminals (A) to each other via intermediate storage element and coupling terminals (B) to each other via intermediate storage element wherein the sections are non-adjacent. A method for balancing a series connection between energy storage devices is also disclosed.

Claims

1. A system for balancing a series connection of energy storage devices comprising:

an intermediate storage element coupled between a pair of non-adjacent sections of one or a number of adjacent energy storage devices of a series connection of energy storage devices, said non-adjacent sections each having a more positive terminal (A) at one end and a more negative terminal (B) at its other end; and

a switching means for switching sequentially between coupling more positive terminals (A) to each other via said intermediate storage element and coupling more negative terminals (B) to each other via said intermediate storage element;

wherein the switching means decouples more positive terminals (A) of the pair of non-adjacent sections upon coupling more negative terminals (B) of the pair of non-adjacent sections, thereby sequentially coupling the intermediate storage element in parallel over a section including one of said pair of non-adjacent sections and the energy storage devices separating said non-adjacent sections, and over a section including the other one of said pair of non-adjacent sections and the energy storage devices separating said non-adjacent sections.

2. A system for balancing a series connection of energy storage devices according to claim 1, wherein said non-adjacent sections comprise one or an equal number of nominally equally sized energy storage devices.

3. A system for balancing a series connection of energy storage devices according to claim 1, comprising a plurality of said pairs and a plurality of respective intermediate storage elements.

4. A system for balancing a series connection of energy storage devices according to claim 3, wherein the plurality of respective intermediate storage elements constitutes one or a plurality of serial strings.

5. A system for balancing a series connection of energy storage devices according to claim 3, wherein two or more pairs comprise overlapping energy storage devices.

6. A system for balancing a series connection of energy storage devices according to claim 3, wherein the switching means concurrently couples all terminals (A) and concurrently couples all terminals (B) with a number of intermediate storage elements equal to the number of respective coupled terminals minus one.

7. A system for balancing a series connection of energy storage devices according to claim 1, wherein said intermediate storage element is a capacitor.

8. A system for balancing a series connection of energy storage devices according to claim 1, wherein the switching means comprises an alternating configuration of p-channel MOSFETs and n-channel MOSFETs.

9. An assembly comprising a series connection of energy storage devices and a system for balancing a series connection of energy storage devices comprising:

an intermediate storage element coupled between a pair of non-adjacent sections of one or a number of adjacent energy storage devices of a series connection of energy storage devices, said non-adjacent sections each having a more positive terminal (A) at one end and a more negative terminal (B) at its other end; and

a switching means for switching sequentially between coupling more positive terminals (A) to each other via said intermediate storage element, and coupling more negative terminals (B) to each other via said intermediate storage element;

wherein the switching means decouples more positive terminals (A) of the pair of non-adjacent sections upon coupling more negative terminals (B) of the pair of non-adjacent sections, thereby sequentially coupling the intermediate storage element in parallel over a section including one of said pair of non-adjacent sections and the energy storage devices separating said non-adjacent sections, and over a section including the other one of said pair of non-adjacent sections and the energy storage devices separating said non-adjacent sections.

10. A method for balancing a series connection of energy storage devices comprising the steps of:

a. providing a series connection of energy storage devices,

b. selecting from said series connection a pair of non-adjacent sections of one or a number of adjacent energy storage devices, said non-adjacent sections to be balanced to each other and each having a more positive terminal (A) at one end and a more negative terminal (B) at its other end,

c. coupling the more positive terminals (A) of said pair of non-adjacent sections via an intermediate storage element,

d. coupling the more negative terminals (B) of said pair of non-adjacent sections via said intermediate storage element, and

e. sequentially repeating step c and d,

wherein said step d comprises decoupling the more positive terminals (A) of the pair of non-adjacent sections, thereby sequentially coupling the intermediate storage element in parallel over a section including one of said pair of non-adjacent sections and the energy storage devices separating said non-adjacent sections, and over a section including the other one of said pair of non-adjacent sections and the energy storage devices separating said non-adjacent sections.

11. A method for balancing a series connection of energy storage devices according to claim 10, said non-adjacent sections comprise one or an equal number of nominally equally sized energy storage devices.

12. A method for balancing a series connection of energy storage devices according to claim 10, wherein a plurality of said pairs is selected, wherein the terminals of each pair are coupled via respective intermediate storage elements, said respective intermediate storage elements constituting one or multiple serial strings.

13. A method for balancing a series connection of energy storage devices according to claim 12, wherein the switching means corresponding to multiple serial strings are controlled by either one single or multiple independent control signals.

14. A method for balancing a series connection of energy storage devices according to claim 12, wherein the step of selecting is performed such that two or more pairs comprise overlapping energy storage devices.

15. A method for balancing a series connection of energy storage devices according to claim 14, wherein each section consists of one energy storage device, wherein said respective intermediate storage elements constitute three serial strings, wherein pairs corresponding to a first and second of said serial strings do not comprise overlapping storage devices, and wherein at least one pair corresponding to a third of said serial strings comprise a storage device overlapping with a storage device of a pair corresponding to the first string, and a storage device overlapping with a storage device of a pair corresponding to the second string.

16. A method for balancing a series connection of energy storage devices according to claim 15, wherein the switching means corresponding to each of the three serial strings are controlled by respective control signals (R1.2), (S1.2), and (T1.2).