Electro-chemical deterioration test method and apparatus

• US 20030020478A1
• Filed: 09/20/2002
• Published: 01/30/2003
• Est. Priority Date: 10/02/1997
• Status: Active Grant

• Current Assignee: Liaisons Electroniques-Mecaniques LEM SA
• Original Assignee: Guardian Link Limited
• Inventors: Scott, Nigel David
• Granted Patent: US 6,747,456 B2
• Time in Patent Office: Days
• 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 an object under test, comprising the steps of providing a portable instrument capable of temporarily applying across the object a controlled frequency electrical signal derived from an internal battery of the instrument, detecting returned data resultant from said application and utilising the returned data and a tailored mathematical algorithm in dedicated computer software to derive the data required.

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 or claim 2, wherein the controlled frequency electrical signal is an oscillating signal.

4. A method according to claim 1 or claim 2, wherein the controlled frequency electrical signal is pseudo-random noise.

5. A method according to any preceding claim, 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 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.

8. A method according to any preceding claim, 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.

10. An instrument adapted to carry out the method according to any one of the preceding claims, said instrument being portable and having an internal battery.

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

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

13. An instrument according to claim 11, 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.

14. An instrument according to any one of claims 10 to 13 including a portable load system adapted to autonomy (discharge) test a single battery cell or monobloc while in circuit, under float charge conditions.

9. A method according to preceding claim, 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 enabling an internal battery of the instrument to be recharged from the battery cells under test.