DEVICE, SYSTEM, AND METHOD FOR MEASURING INTERNAL IMPEDANCE OF A TEST BATTERY USING FREQUENCY RESPONSE

• US 20170254859A1
• Filed: 03/03/2016
• Published: 09/07/2017
• Est. Priority Date: 03/03/2016
• Status: Active Grant

• Current Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Original Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Inventors: CHRISTOPHERSEN, JON P., MORRISON, WILLIAM H., MORRISON, JOHN L.
• Granted Patent: US 10,345,384 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• 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: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Battery impedance testing devices, circuits, systems, and related methods are disclosed. An impedance measurement device includes a current driver configured to generate an excitation current signal to be applied to a test battery responsive to a control signal, and a processor operably coupled with the current driver. The processor is configured to generate the control signal during an auto-ranging mode and a measuring mode. The auto-ranging mode applies the excitation current signal to the test battery over a plurality of different amplitudes to measure a response to the excitation current signal at each amplitude. The measuring mode applies the excitation current signal to the test battery for an amplitude responsive to the results of the auto-ranging mode. Improved sensitivity and resolution may be achieved for low impedance batteries with a rapid measurement time.

Claims

1. An impedance measurement device, comprising:

a current driver configured to generate an excitation current signal to be applied to a test battery responsive to a control signal; and

a processor operably coupled with the current driver, the processor configured to generate the control signal during an auto-ranging mode and a measuring mode, wherein;

the auto-ranging mode applies the excitation current signal to the test battery over a plurality of different amplitudes to measure a response to the excitation current signal at each amplitude; and

the measuring mode applies the excitation current signal to the test battery for an amplitude responsive to the results of the auto-ranging mode.

2. The impedance measurement device of claim 1, further comprising a preamplifier including the current driver and a signal measuring module configured to measure electrical signals responsive to the excitation current signal being applied to the test battery.

3. The impedance measurement device of claim 2, wherein the current driver exhibits a total gain of greater than approximately 20.

4. The impedance measurement device of claim 3, wherein the total gain is greater than approximately 60.

5. The impedance measurement device of claim 2, wherein the current driver includes at least three cascading gain stages with outputs from each cascading gain stage being fed back to the processor to determine a plurality of buck voltages transmitted back from the processor to the current driver.

6. The impedance measurement device of claim 5, wherein the at least three cascading gain stages include a first gain stage exhibiting a first gain of approximately −

0.166, a second gain stage exhibiting a second gain of approximately −

20, and a third gain stage exhibiting a third gain of approximately 20.

7. The impedance measurement device of claim 1, wherein the current driver is configured to generate at least one of a sum-of-sinusoids (SOS) current signal or a sum of alternating sines, cosines (ASC) signal.

8. The impedance measurement device of claim 1, wherein the current driver includes differential current sources including a pull up current source and a pull down current source operably coupled to the test battery.

9. An impedance measurement system, comprising:

a test battery; and

an impedance measurement device operably coupled to the test battery, wherein the impedance measurement device includes;

a preamplifier including a current driver and a signal measuring module operably coupled with the test battery;

a current control signal generator operably coupled with the preamplifier;

a data acquisition system operably coupled with the preamplifier; and

a processor operably coupled with the current control signal generator and the data acquisition system, wherein the processor is configured to;

control the current control signal generator to transmit a current control signal to the preamplifier during an auto-ranging mode to cause the current driver to generate an excitation current signal exhibiting a range of amplitudes;

control the data acquisition system to analyze the response of the test battery from the signal measuring module during the auto-ranging mode;

control the current control signal generator to transmit the current control signal to the preamplifier during a measuring to cause the current driver to generate the excitation current signal exhibiting a selected amplitude based, at least in part, on analyzing the response of the test battery during the auto-ranging mode; and

control the data acquisition system to analyze the response of the test battery from the signal measuring module during the measuring mode to determine an impedance of the test battery.

10. The impedance measurement system of claim 9, wherein the battery includes one or more energy storage cells.

11. The impedance measurement system of claim 9, wherein the data acquisition system includes an impedance computation module that executes a data processing method to determine the impedance of the test battery, wherein the data processing method is configured to capture at least one of a voltage time record or a current time record, and to discard samples within the voltage or current time records that are either above or below a full scale for the respective time record.

12. The impedance measurement system of claim 9, wherein the data acquisition system includes an impedance computation module that executes a data processing method to determine the impedance of the test battery, wherein the data processing method is selected from the group consisting of a time crosstalk compensation (TCTC) method, a harmonic orthogonal synchronous transform (HOST) method, a Fast Summation Transformation (FST) method, and a triads based Generalized Fast Summation Transformation (GFST) method.

13. The impedance measurement system of claim 9, further comprising a remote computer operably coupled with the impedance measurement device, the remote computer configured to control the impedance measurement device and receive impedance data from the impedance measurement device.

14. The impedance measurement system of claim 9, wherein the preamplifier further includes a smoothing filter operably coupled between the current control signal generator and the current driver.

15. The impedance measurement system of claim 9, wherein the excitation current signal includes at least one of a sum-of-sinusoids (SOS) current signal or a sum of alternating sines, cosines (ASC) signal for each of the auto-ranging mode and the measuring mode.

16. The impedance measurement system of claim 9, wherein the test battery exhibits an internal impedance between about 1 mOhm and 5 mOhm.

17. The impedance measurement system of claim 16, wherein the impedance measurement device exhibits a resolution of at least 0.01 mOhm with a measurement time of about 10 seconds or less.

18. The impedance measurement system of claim 9, further comprising a vehicle including the test battery.

19. The impedance measurement system of claim 18, wherein the vehicle further includes the impedance measurement device.

20. A method of measuring impedance of a test battery, the method comprising:

applying an excitation current signal to a test battery including a plurality of pulses exhibiting different amplitudes during an auto-ranging mode;

measuring an electrical signal from the test battery responsive to the excitation current signal over the plurality of different amplitudes;

applying the excitation current signal to the test battery exhibiting a fixed amplitude during a measuring mode, wherein the fixed amplitude is set based, at least in part, on an analysis of the electrical signal measured during the auto-ranging mode; and

measuring the electrical signal from the test battery responsive to the excitation current signal exhibiting the fixed amplitude during the measuring mode to determine an internal impedance of the test battery.

21. The method of claim 20, wherein the fixed amplitude corresponds to an amplitude within the plurality of pulses that is at least one pulse before voltage clipping was determined to have occurred in the electrical signal during the auto-ranging mode.

22. The method of claim 20, wherein applying the excitation current signal to the test battery includes applying the excitation current signal to the test battery exhibiting an average mid-range voltage between about 40 V to 60 V or about 250 V to 350 V.