Electro-chemical deterioration test method and apparatus

• US 7,495,448 B2
• Filed: 05/11/2004
• Issued: 02/24/2009
• Est. Priority Date: 10/02/1997
• Status: Expired due to Fees

• Current Assignee: Liaisons Electroniques-Mecaniques LEM SA
• Original Assignee: Lem Heme Limited (LEM Holding SA)
• Inventors: Scott, Nigel David, Wellstead, Peter, Schooling, Steven
• Primary Examiner(s): TSO, EDWARD H
• Application Number:
  US10/843,528
• Publication Number:
  US 20040212368A1
• Time in Patent Office: 1,750 Days
• Field of Search: 324/426, 324/427, 324/428, 324/430, 324/433, 324/436, 320/134, 320/136, 320/DIG.12, 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

An apparatus for deriving data concerning the electro-chemical characteristics of a plurality of individual electro-chemical cells or corrosion processes is disclosed. In one aspect, the apparatus includes means for temporarily applying across a cell or a process a controlled multi-frequency electrical signal; means for detecting returned data resultant from said application, and means for utilizing the returned data with to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance, an electro-chemical resistance, and a double-layer capacitance.

Claims

1. An instrument, comprising:

means for temporarily applying across a cell or a process a controlled multi-frequency electrical signal;

means for detecting returned data resultant from said application, and

means for utilizing the returned data with to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance, an electro-chemical resistance, and a double-layer capacitance.

2. An instrument according to claim 1, further comprising means for storing the returned data for subsequent analysis.

3. An instrument according to claim 1, wherein the controlled multi-frequency electrical signal is an oscillating signal or pseudo-random noise.

4. An instrument according to claim 1, wherein the returned data is measured for both current and voltage simultaneously.

5. An instrument according to claim 4, wherein the DC component of the measured data is removed therefrom.

6. An instrument according to claim 1, wherein when the controlled multi-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 object under test, and the negative half-cycle is derived from the object under test, and the negative half-cycle is derived from the object under test and applied to the instrument'"'"'s internal battery whereby the internal battery may be recharged from the object under test in a minimal period.

7. An instrument 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 object under test there is also provided a simple graphical interpretation of the actual characteristics.

8. An instrument according to claim 1, wherein the instrument is applied to 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.

9. An instrument according to claim 1, said instrument being portable and further comprising an internal battery.

10. An instrument according to claim 9, when applied to measure and define the electro-chemical deterioration of a battery, the components of the instrument being such as to generate substantially no net energy transfer between the battery under test and the internal battery within the instrument.

11. An instrument according to claim 10, having terminal connectors adapted to be applied to the external terminals of a battery cell to be tested.

12. An instrument according to claim 10, wherein its components include a flying bridge such that the internal battery of the instrument transmits a current through the battery under test and the latter transmits a current through the internal battery.

13. An instrument according to claim 9, including a portable load system adapted to autonomy (discharge) test a single battery cell or monobloc while in circuit, under float charge conditions.

14. An instrument for deriving data concerning the electro-chemical characteristics of an electro-chemical cell in circuit or corrosion process in situ, comprising:

a multi-frequency electrical signal generator capable of temporarily applying across the cell or process a controlled multi-frequency electrical signal;

data acquisition means for detecting returned data resultant from said application, and

a dedicated computer with computer software algorithms capable of resolving the data into at least three of its electro-chemical constituents, including a metallic resistance, an electro-chemical resistance, and a parallel capacitance.

15. An instrument according to claim 14, provided as a portable instrument of sufficiently low mass to be carried, while testing, over extended periods and without strain to the operator.

16. An instrument according to claim 14, wherein the controlled multi-frequency electrical signal is an oscillating signal or is pseudo-random noise.

17. An instrument to claim 14, the components of which, including an internal battery thereof, are such as to generate substantially no net energy transfer between a battery under test and an internal battery of the instrument.

18. An instrument according to claim 14, including a portable load system adapted to carry out an automatic discharge of a single battery cell or monobloc while in circuit, under float charge conditions.

19. An apparatus for deriving data concerning the electro-chemical characteristics of a plurality of individual electro-chemical cells or corrosion processes, comprising:

a plurality of sealed, valve regulated open lead-acid cells;

an instrument, capable of;

temporarily applying across at least one of the cells a controlled frequency electrical signal to measure the service capacity of individual cells while in service under float charge conditions,

detecting returned voltage and current data resultant from said application;

utilizing the returned data and a tailored mathematical algorithm in dedicated computer software to resolve the data, with complex impedance, into at least three of its electro-chemical constituents, including a series metallic resistance, an electro-chemical resistance, and a double-layer capacitance; and

storing the data resulting from the application for subsequent analysis.

20. An apparatus according to claim 19, wherein the controlled frequency electrical signal is an oscillating signal or a pseudo-random noise.

21. An apparatus according to claim 19, 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.

22. An apparatus according to claim 19, 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.

23. A method of deriving data concerning the electro-chemical characteristics of an object under test, comprising the steps of providing a portable instrument capable of temporarily applying across the object a controlled multi-frequency electrical signal derived from an internal battery of the instrument, detecting returned data resultant from said application and utilising the returned data and an original tailored mathematical algorithm in dedicated computer software to resolve the data into at least three of its electro-chemical constituents, including a series metallic resistance, an electro-chemical resistance, and a double-layer capacitance.