Energy device analysis and evaluation

• US 6,411,098 B1
• Filed: 12/08/1998
• Issued: 06/25/2002
• Est. Priority Date: 03/27/1996
• Status: Expired due to Term

• Current Assignee: Biourja Energy Systems, Llc
• Original Assignee: World Energy Labs Incorporated
• Inventors: Laletin, William H.
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): Nguyen, Vincent Q.
• Application Number:
  US09/155,308
• Time in Patent Office: 1,295 Days
• Field of Search: 324/426, 324/713, 324/72.5, 324/436, 320/161
• US Class Current: 324/436
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382

Abstract

A method and apparatus for creating, measuring and analyzing polarization voltages developed across an element, such as an electronic component or an electrochemical energy cell, or network of such elements, in response to a current mode excitation provided by a driver composed of a voltage controlled voltage source connected to one terminal of a Device Under Test and a voltage controlled current source connected to the other terminal of a Device Under Test. A voltage sensor, also connected across the Device Under Test, determines the magnitude and polarity of any potential appearing across the DUT; whenever the excitation current is exactly zero, this measured potential will be equal to the Open Circuit Potential of the DUT. This configuration of driver and sensor is known as a Kelvin connection. In response to the sensor'"'"'s output, an internal control circuit adjusts the magnitude and polarity of an offset controlling signal provided to the voltage controlled voltage source, such that any intrinsic open circuit potential exhibited by the device under test appears centered with respect to the common ground potential of the apparatus. The offset controlling signal is also applied to the inputs of the sensor preamplifier such that the only the polarization voltage component of the DUT'"'"'s voltage response to the excitation current appears at the output of the preamplifier. The characteristics of the resulting polarization voltage signal appearing at the output of the sensor preamplifier may be analyzed to yield both qualitative and quantitative information about the Device Under Test.

Claims

1. A system for determining the polarization voltages developed in response to an excitation signal applied to a device, the system comprising:

a controlled-current source configured for connection to a first terminal of the device;

a controlled-voltage source configured for connection to a second terminal of the device,

wherein the controlled-voltage source is configured to provide self-centering and auto-polarity for the system;

a sensor configured, to sense a voltage across the device and to produce a sensor signal in response to the voltage sensed across the device, and

a controller connected to the controlled-current source, the controlled-voltage source, and the sensor, the controller being configured to determine polarization voltages in response to the sensor signal.

2. The system of claim 1, wherein the controller comprises a microprocessor and associated circuitry.

3. The system of claim 1, wherein the controller comprises analog circuitry.

4. The system of claim 1, further comprising Kelvin connection circuitry, the Kelvin connection circuitry comprising:

a first lead connected to the controlled-current source and configured for connection to the first terminal of the device,

a second lead connected to the controlled-voltage source and configured for connection to the second terminal of the device, and

third and fourth leads connected to the sensor and configured to be connected to, respectively, the first and second terminals of the device.

5. The system of claim 1, wherein the controlled-current source is configured to provide a symmetric, bipolar square wave to the first terminal of the device.

6. The system of claim 1, further comprising a feedback loop between the sensor and the controller, the feedback loop being configured to eliminate a portion of the voltage across the device corresponding to a bias voltage of the device so that the sensor signal reflects only a portion of the voltage across the device.

7. The system of claim 6, wherein the controller is configured to provide self-centering relative to the device by supplying a voltage equal to one half of the DC offset voltage to the controlled-voltage source.

8. A method of determining polarization voltages developed in response to an excitation signal applied to a device, the method comprising:

connecting a controlled-current source to a first terminal of the device;

connecting a controlled-voltage source to a second terminal of the device,

wherein the controlled-voltage source is controlled to produce a voltage having a magnitude equal to one half of the non-varying portion of the sensed voltage;

using a controlled-current source to apply a bipolar, symmetric square wave or other waveforms to the device;

sensing a voltage across the device to produce a sensor signal in response to the voltage sensed across the device, and;

modifying the sensor signal to eliminate effects of a bias voltage of the device; and

determining polarization voltages in response to the sensor signal.

9. The method of claim 8, further comprising generating a graphical representation of the polarization voltage suitable for immediate visual inspection and analysis.

10. The method of claim 8, further comprising comparing the polarization voltage to baseline data for a class of devices to which the device belongs to assess a relative condition of the device.