Management scheme for multiple battery cells

• US 9,005,788 B2
• Filed: 07/06/2009
• Issued: 04/14/2015
• Est. Priority Date: 07/06/2009
• Status: Active Grant

• Current Assignee: Amperex Technology Limited (TDK Corporation)
• Original Assignee: Amperex Technology Limited (TDK Corporation)
• Inventors: Zhu, Li-Yan
• Primary Examiner(s): Ruddock, Ula C.
• Assistant Examiner(s): CHERNOW, FRANK A
• Application Number:
  US12/459,654
• Publication Number:
  US 20110003182A1
• Time in Patent Office: 2,108 Days
• Field of Search: 429/90, 320/116, 320/124
• US Class Current: 429/90
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/617 for achieving uniformity or desired distribution of temperature
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A series-parallel battery system with a buffer resistor coupled to each junction of batteries or battery cells. Buffer resistors on the same row are coupled to a measurement node. Terminals of the battery system and the measurement nodes are treated as measurement points that are coupled to a conventional battery management unit. The buffer resistors provide a means for limiting in-rush current and a means for maintaining voltage balance across the row of batteries in the parallel columns of batteries. A control unit in series with each series of batteries monitors current in the series and comprises a switch to deactivate the column when the current exceeds a set of predetermined current levels.

Claims

1. A battery management system, comprising:

a) a series-parallel battery system further comprising m columns, wherein each column comprises n batteries connected in series between negative and positive terminals of the battery system, and wherein m and n are integers greater than one;

b) a positive battery terminal of each battery in a top row of batteries in the m columns coupled to a positive terminal of the battery system and a negative battery terminal of each battery in a row of bottom batteries in the m columns coupled to a minus terminal of the battery system;

c) a single row of positive battery terminals formed from a single row of batteries located below said top row of batteries, wherein each positive battery terminal of said single row of positive battery terminals connected by a buffer resistor to a single measurement node of a battery management unit (BMU) located in said single row of positive battery terminals, wherein a value of said buffer resistor is small enough to maintain a voltage balance across said row of battery terminals and large enough in resistance value to limit in-rush current when a short develops; and

d) said measurement nodes connect to said battery management unit (BMU) to provide a measurement of battery system performance and detect a failure of said battery system.

2. The system of claim 1, wherein said series-parallel battery system further comprises a control unit in each column of the m columns to adjust current distribution among the m columns.

3. The system of claim 2, wherein said control unit further comprises a current sensor to monitor current and a switch controlled by the battery management unit (BMU) to turn off a failing column of the m columns of batteries.

4. The system of claim 3, wherein said BMU monitors voltage of each battery in the battery system.

5. The system of claim 1, wherein said buffer resistors are connected between each positive battery terminal in a row of positive battery terminals and the measurement node except for one battery terminal, which is coupled directly to the measurement node.

6. The system of claim 1, wherein said batteries are selected and grouped such that batteries in the same column are of approximately the same capacity, and a product of capacity and internal resistance of the batteries are approximately identical among columns in the battery system.

7. The system of claim 1, wherein said battery system further comprises packaging and cooling arranged such that an average temperature of batteries in each column is approximately identical.

8. The system of claim 1, wherein said buffer resistors are larger in resistance value than an internal resistance of the batteries to which the buffer resistors are connected.