System and method for measuring battery internal resistance

• US 8,063,643 B2
• Filed: 02/09/2009
• Issued: 11/22/2011
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Vertiv Corporation (Vertiv Holdings Co.)
• Original Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Inventors: Radzikowski, Marc Jeffrey, Deveau, Edward Winsor
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US12/367,783
• Publication Number:
  US 20090224771A1
• Time in Patent Office: 1,016 Days
• Field of Search: 324/430, 702/57
• US Class Current: 324/430
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/386 using test-loads
• 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

In one aspect the present disclosure relates to a system for measuring an internal resistance of a battery. The system may involve: a processor; a load module responsive to the processor for applying a load across the battery; a current sense subsystem for sensing the current flowing to the load module and generating a sensed current signal in accordance therewith; a multiplexer module in communication with the current sense subsystem for detecting voltages with the load coupled across the battery and uncoupled from the battery, and generating voltage signals in accordance therewith; and a filtering and amplification subsystem responsive to the multiplexer module, for filtering and amplifying a level of each of the voltage signals to produce modified voltage signals for use by the processor in determining the battery internal resistance.

Claims

1. A system for measuring an internal resistance of a battery, the system comprising:

a processor;

a load module responsive to the processor for applying a load across the battery;

a current sense subsystem for sensing the current flowing to the load module and generating a sensed current signal in accordance therewith; and

a multiplexer subsystem in communication with the current sense subsystem for detecting voltages with the load module coupled across the battery and released from the battery, and generating voltage signals in accordance therewith; and

a filtering and amplification subsystem responsive to said multiplexer subsystem, for filtering and amplifying a level of each of said voltage signals to produce a pair of modified voltage signals for use by said processor in determining said internal battery resistance of said battery.

2. The system of claim 1, wherein said load module comprises a configurable load module responsive to said processor for applying one of a plurality of different loads across said battery, depending upon a control signal applied to said load module.

3. The system of claim 1, wherein said multiplexer is responsive to said processor to output a selected one of said voltage signal and sensed current signal to said filtering and amplification subsystem.

4. The system of claim 1, wherein said filtering and amplification subsystem comprises a low pass filter for filtering said voltage signals and producing a voltage signal having a reduced bandwidth.

5. The system of claim 4, wherein said filtering and amplification subsystem further comprises a level shifting component for level shifting each of said voltage signals.

6. The system of claim 1, wherein:

said filtering and amplification subsystem comprises a low pass filter for generating a reduced bandwidth voltage signals, and an amplifier responsive to said processor for amplifying said reduced bandwidth voltage signals in accordance with a predetermined gain, to generate said modified voltage signals; and

said modified voltage signals form filtered, amplified voltage signals from which a step portion thereof may be analyzed by said processor.

7. The system of claim 1, wherein said predetermined gain comprises one of a plurality of different gains selected by said processor.

8. The system of claim 1, further comprising a temperature module for monitoring a temperature of said battery and providing a temperature signal to an input of said processor that is indicative of said temperature of said battery.

9. The system of claim 1, further comprising a power supply module for filtering a signal from said battery that is used to power said system.

10. The system of claim 9, further comprising an independent battery for supplying power to said power supply module 76.

11. The system of claim 1, wherein said modified voltage signals define a magnified portion of a voltage step formed as said battery recovers after said load has been applied to said battery.

12. The system of claim 1, further comprising at least one of:

a wireless network module for communicating an output of said processor relating to said internal resistance of said battery; and

a wired network module for communicating an output of said processor relating to said internal resistance of said battery.

13. The system of claim 12, further comprising a data archive for storing information generated by said processor pertaining to said internal resistance of said battery.

14. A system for measuring an internal resistance of a battery, the system comprising:

a processor;

a load module responsive to the processor for applying a load across the battery;

a current sense subsystem for sensing the current flowing to the load module and generating a sensed current signal in accordance therewith; and

a multiplexer module in communication with the current sense subsystem for detecting voltages across the load module and generating a pair of voltage signals in accordance therewith, one with the load coupled across the battery and one without the load coupled across the battery; and

a level shifting, filtering and amplification subsystem responsive to said multiplexer module and said current sense subsystem, that;

filters said voltage signals to reduce a bandwidth of each said voltage signal, to thus produce reduced bandwidth voltage signals;

level shifts said reduced bandwidth voltage signals to produce level shifted voltage signals; and

amplifies said level shifted voltage signals to produce a pair of modified voltage signals, and wherein said modified voltage signals form an amplified portion of a voltage step of said level shifted voltage signal as said battery recovers after said load has been applied to said battery.

15. The system of claim 14, wherein said load module comprises a configurable load module responsive to said processor for applying one of a plurality of different loads across said battery, depending upon a control signal applied to said load module by said processor.

16. The system of claim 14, further comprising at least one of:

a temperature module for sensing a temperature of said battery and providing a related signal to said processor; and

a memory for storing information used by said processor during operation of said system.

17. The system of claim 14, wherein said level shifting, filtering and amplification subsystem comprises:

a low pass filter for filtering said voltage signals to produce reduced bandwidth voltage signals; and

a variable gain amplifier controlled by a gain signal from said processor.

18. The system of claim 14, further comprising at least one of:

a wireless network module for communicating an output of said processor relating to said internal resistance of said battery; and

a wired network module for communicating an output of said processor relating to said internal resistance of said battery.

19. The system of claim 14, further comprising at least one of:

an independent battery for providing power to said system; and

a data archive for storing information relating to said internal battery resistance for future use.

20. A method for measuring an internal resistance of a battery, the method comprising:

applying a load across a pair of terminals of said battery;

sensing a current flowing through said load and generating a sensed current signal in accordance therewith;

measuring a change in voltage across said battery to produce a while the load is applied across the battery and while the load is released from the battery, to generate a pair of voltage signals;

filtering said voltage signals to produce reduced bandwidth voltage signals;

level shifting the reduced bandwidth voltage signals to produce shifted voltage signals;

amplifying the shifted voltage signal to produce amplified voltage signals; and

using the amplified voltage signals and said sensed current signal to calculate said internal resistance of said battery.