Electro-chemical deterioration test method and apparatus

• US 6,747,456 B2
• Filed: 09/20/2002
• Issued: 06/08/2004
• Est. Priority Date: 10/02/1997
• Status: Expired due to Term

• Current Assignee: Liaisons Electroniques-Mecaniques LEM SA (Werner O. Weber)
• Original Assignee: Guardian Link Limited
• Inventors: Scott, Nigel David
• Primary Examiner(s): Hirshfeld, Andrew H.
• Assistant Examiner(s): Hamdan, Wasseem H.
• Application Number:
  US10/252,035
• Publication Number:
  US 20030020478A1
• Time in Patent Office: 627 Days
• Field of Search: 324/426, 324/430, 324/428, 324/432, 324/427, 320/136, 320/134, 320/DIG.12, 424/433, 424/436, 702/65
• US Class Current: 324/426
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery

Abstract

A portable instrument capable of evaluating the electro-chemical deterioration of an object under test such as a multi-cell valve regulated battery (10) and comprising means capable of temporarily applying across a battery cell a controlled frequency electrical signal derived from an internal battery (11) within the instrument, the signal being an oscillatory current or voltage controlled injected signal, further means for detecting returned data resultant from the signal application, and utilizing the data and a tailored mathematical algorithm in dedicated computer software to derive the data required. Such an instrument may be used to test battery systems of the type required for uninterruptible back-up power supplies in large industrial installations.

Claims

1. A method of deriving data concerning the electro-chemical characteristics of a plurality of individual electro-chemical cells or corrosion processes, comprising the steps of:

providing an instrument capable of temporarily applying across a cell or a process a controlled multi-frequency electrical signal,

detecting returned data resultant from said application, and

utilizing the returned data with computer software algorithms to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance (R_Ω

). an electro-chemical resistance (R_e), and a double-layer capacitance (C_dl).

2. A method according to claim 1, when applied to measure the service capacity of individual cells of multi-cell valve regulated lead-acid batteries while in service, the resultant data being stored for subsequent analysis.

3. A method according to claim 1, wherein the controlled frequency electrical signal is an oscillating signal.

4. A method according to claim 1, wherein the controlled frequency electrical signal is pseudo-random noise.

5. A method according to claim 1, wherein the returned data is measured for both current and voltage simultaneously.

6. A method according to claim 5, wherein the DC component of the measured data is removed therefrom.

7. A method according to claim 1, wherein when the controlled frequency electrical signal is sinusoidal, a flying bridge is included whereby the positive half-cycle is derived from the instrument'"'"'s internal battery via the bridge and applied to the cell or process, the negative half-cycle is derived from the cell or process, and applied to the instruments internal battery whereby the internal battery may be recharged from the cell or process in a minimal period.

8. A method according to claim 1, including the use of a second mathematical model based on complex impedance values and others such as DC current and temperature whereby in addition to the ability to view data and graphical representations of the characteristics of the cell or process there is also provided a simple graphical interpretation off the actual characteristics.

9. A method according to claim 1, wherein the instrument is applied to scaled, valve regulated open lead-acid cells to measure the service capacity of individual cells of a multi-cell battery while in service under float charge conditions and causing an internal battery of the instrument to be recharged from the battery cells under test.

10. A method according to claim 5, wherein the instrument is operated such that substantially no net energy transfer occurs between the instrument and the object under test.

11. A method according to claim 1, wherein the data is resolved into at least three of its electro-chemical constituents, including capacitance.

12. The method of claim 1, wherein the instrument is portable.

13. The method of claim 1, wherein the controlled frequency electrical signal is derived from an internal battery of the instrument.

14. The method of claim 1, wherein the controlled frequency electrical signal is derived from one of the electro-chemical cells.

15. A method of deriving data concerning the electro-chemical characteristics of a plurality of individual electro-chemical cells or corrosion processes, comprising the steps of:

providing an instrument capable of temporarily applying across a cell or a process a controlled multi-frequency electrical signal derived from an internal battery of the instrument,

applying the instrument to a plurality of sealed, valve regulated open lead-acid cells to measure the service capacity of individual cells of a multi-cell battery while in service under float charge conditions and causing an internal battery of the instrument to be recharged from the battery cells under test,

detecting returned voltage and current data resultant from said application;

utilizing the returned data with computer software algorithms to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance (R_Ω

), a parallel electro-chemical resistance (R_e). and a double-layer capacitance (C_dl); and

storing the data resulting from the application for subsequent analysis.

16. A method according to claim 15, wherein the controlled frequency electrical signal is an oscillating signal or a pseudo-random noise.

17. A method according to claim 15, wherein when the controlled frequency electrical signal is sinusoidal, a flying bridge is included whereby the positive half-cycle is derived from the instrument'"'"'s internal battery via the bridge and applied to the cell or process, and the negative half-cycle is derived from the cell or process, and the negative half-cycle is derived from the cell or process and applied to the instrument'"'"'s internal battery whereby the internal battery may be recharged from the cell or process in a minimal period.

18. A method according to claim 15, including the use of a second mathematical model based on complex impedance values and others such as DC current and temperature whereby in addition to the ability to view data and graphical representations of the characteristics of the cell or process there is also provided a simple graphical interpretation of the actual characteristics.