Battery testing dynamic delta voltage measurement

• US 8,502,541 B2
• Filed: 11/01/2010
• Issued: 08/06/2013
• Est. Priority Date: 11/01/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Chalfant, Robert W., Lupienski, Jason A., Tompkins, John D.
• Primary Examiner(s): Dunn, Drew A
• Assistant Examiner(s): PELTON, NATHANIEL R
• Application Number:
  US12/916,754
• Publication Number:
  US 20120105071A1
• Time in Patent Office: 1,009 Days
• Field of Search: 324/429, 324/433
• US Class Current: 324/433
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method of evaluating battery packs is described. The method includes measuring a cell open voltage for each battery cell group in a section of battery cells; measuring a voltage under charge, or a voltage under load, or both, at a predetermined time interval for each battery cell group in the section of battery cells; determining the magnitude of the difference between the open cell voltage and the voltage under charge, or the voltage under load, or both, for each battery cell group in the section of battery cells by subtracting the voltage under charge from the cell open voltage, or subtracting the voltage under load from the cell open voltage, or both; and determining if the magnitude of the difference between the open cell voltage and the voltage under charge, or the voltage under load, or both, for each battery cell group in the section of battery cells exceeds a predetermined level.

Claims

1. A method of evaluating battery packs comprising:

measuring a cell open voltage for each battery cell group in a section of battery cells;

measuring a voltage under charge, or a voltage under load, or both, at a predetermined time interval for each battery cell group in the section of battery cells;

determining a magnitude of the difference between the open cell voltage and the voltage under charge, or the voltage under load, or both, for each battery cell group in the section of battery cells by subtracting the voltage under charge from the cell open voltage, or

subtracting the voltage under load from the cell open voltage, or both; and

determining a maximum difference between the open cell voltage and the voltage under charge, or the voltage under load, or both;

determining a minimum difference between the open cell voltage and the voltage under charge, or the voltage under load, or both;

determining a range by subtracting the minimum difference from the maximum difference; and

determining if the range exceeds a predetermined level.

2. The method of claim 1 wherein the predetermined time interval is less than about 20 sec.

3. The method of claim 1 wherein the predetermined time interval is less than about 10 sec.

4. The method of claim 1 wherein the predetermined time interval is less than about 5 sec.

5. The method of claim 1 wherein if the range exceeds the predetermined level, repairing the group.

6. The method of claim 5 wherein repairing the group comprises rewelding the group.

7. The method of claim 6 further comprising retesting the repaired group.

8. The method of claim 5 wherein repairing the group comprises replacing a module containing the group.

9. The method of claim 8 further comprising retesting the repaired group.