Battery characterization system

• US 20030236656A1
• Filed: 06/21/2002
• Published: 12/25/2003
• Est. Priority Date: 06/21/2002
• Status: Abandoned Application

• Current Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Dougherty, Thomas J.
• Application Number:
  US10/177,697
• Publication Number:
  US 20030236656A1
• Time in Patent Office: Days
• US Class Current: 703/14
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

A system for modeling a lead-acid battery is disclosed. A system for modeling a lead-acid battery is also disclosed. An equivalent circuit model of a battery comprising an impedance circuit for simulating the electrochemical charging and discharging of the battery is also disclosed. A circuit for modeling a lead-acid battery having an RC network for simulating the impedance of cells of the battery is also disclosed. A method of modeling a lead-acid battery with an electrical circuit comprising a charging circuit, an electrochemical reaction circuit, and a voltage drop circuit is also disclosed. A method for constructing an equivalent electrical circuit model of a lead-acid battery is also disclosed.

Claims

1. A system for modeling a lead-acid battery in the form of a representative electrical circuit comprising:

an electrical circuit comprising;

a charging circuit configured to simulate the initial charging of the battery and having a capacitor configured for charging to a first voltage;

an electrochemical reaction circuit comprising;

a plurality of capacitors configured to simulate the charging and discharging of the battery due to internal chemical reactions and configured for charging to a second voltage;

a plurality of resistors for simulating the resistance of the battery;

a voltage drop circuit including a resistor and a capacitor configured to simulate capacitive charging and discharging of the battery and configured for charging to a third voltage;

wherein the representative circuit is implemented through a computer-based simulation.

2. The system of claim 1 wherein the first voltage is at least about 11 volts, the second voltage is at least about 2 volts, and the third voltage is at least about 13 volts.

3. The system of claim 1 wherein the charging circuit includes a double layer capacitance circuit.

4. The system of claim 2 wherein the charging circuit includes a diode for limiting the charge across the capacitor of the charging circuit.

5. The system of claim 3 wherein the electrochemical reaction circuit comprises an RC ladder.

6. The system of claim 5 wherein a first resistor of the plurality of resistors simulates an electrical resistance of the battery.

7. The system of claim 6 wherein a second resistor of the plurality of the resistors simulates an ionic resistance of the battery.

8. The system of claim 7 wherein the second resistor comprises at least one of a positive temperature coefficient resistor and a negative temperature coefficient resistor.

9. The system of claim 6 wherein a first capacitor of the plurality of capacitors simulates an outside layer of a plate of the battery.

10. The system of claim 9 wherein a second capacitor of the plurality of capacitors simulates an inside layer of a plate of the battery.

11. The system of claim 10 further comprising a device for simulating a slope of the open circuit voltage of the battery versus the relative state of charge of the battery due to at least one of time and temperature.

12. The system of claim 11 wherein the device comprises a MOSFET.

13. A system for modeling a lead-acid battery in the form of a representative electrical circuit comprising:

an electrochemical reaction circuit configured to simulate the charging and discharging of the battery between a predetermined base voltage and a predetermined open circuit voltage;

a charging circuit configured to charge the electrochemical reaction circuit to the base voltage;

wherein the representative circuit is implemented through a software-based simulation.

14. The system of claim 13 further comprising a voltage drop circuit configured to simulate the effects of the formation of lead sulfate in the battery.

15. The system of claim 14 wherein the charging circuit comprises a capacitor and a resistor electrically coupled in parallel.

16. The system of claim 15 wherein the capacitor and resistor provide a charging slope to the base voltage.

17. The system of claim 16 wherein the electrochemical reaction circuit comprises an RC ladder network.

18. The system of claim 16 wherein the RC ladder network includes a first resistor for simulating an ionic component of an internal resistance of the battery and a second resistor for simulating an electronic component of the internal resistance of the battery.

19. The system of claim 18 wherein the voltage drop circuit comprises a resistor and a capacitor.

20. An equivalent circuit model of a battery comprising an impedance circuit model for simulating the electrochemical charging and discharging of the battery, an improvement comprising:

an initial charge circuit model for charging the equivalent circuit model to a predetermined voltage value.

21. The equivalent circuit model of claim 20 further comprising an electrochemical reaction circuit model comprising a plurality of capacitor models for simulating the charging and discharging of the battery due to chemical reactions and a plurality of resistor models for simulating the impedance of the battery.

22. The equivalent circuit model of claim 21 further comprising a voltage drop circuit model including a capacitor model and a resistor model for modeling capacitive charging and discharging of the battery.

23. A circuit for modeling a lead-acid battery having an RC network for simulating the impedance of the battery, an improvement comprising:

a charge circuit comprising a capacitor, a resistor, and a diode each electrically coupled in parallel, the charge circuit being electrically coupled to the RC network for charging the circuit to a base voltage;

wherein the RC network charges the circuit between the base voltage and an open circuit voltage to simulate the electrochemical charging of the battery.

24. The circuit of claim 23 wherein the RC network comprises at least one MOSFET for charging and discharging a plurality of capacitors of the RC network.

25. The circuit of claim 24 further comprising a programmable device to selectively activate and deactivate the at least one MOSFET.

26. The circuit of claim 25 wherein the programmable device is programmed to model the effect of time and temperature on the circuit.

27. The circuit of claim 26 wherein the base voltage is at least about 11 volts.

28. The circuit of claim 23 wherein the circuit is simulated using numerical values programmed in a computer-based simulation model.

29. A method of modeling a lead-acid battery with an electrical circuit comprising a charging circuit, an electrochemical reaction circuit, and a voltage drop circuit, comprising:

charging a capacitor of the initial charging circuit at a predetermined rate to a predetermined voltage, thereby simulating the initial charging of the battery;

charging and discharging a plurality of capacitors of the electrochemical circuit, thereby simulating a slope of an open circuit voltage of the battery versus a relative state of charge of the battery;

charging and discharging a capacitor of the voltage drop circuit, thereby simulating a capacitive charging and discharging of the battery.

30. The method of claim 29 further comprising limiting the charging of the capacitors with a diode.

31. The method of claim 30 further comprising selectively electrically coupling a MOSFET to the electrochemical circuit, thereby simulating the effects of time and temperature.

32. A battery characterization system implemented through a control program comprising a representative circuit, the battery characterization system comprising:

a model of a representative electrical circuit comprising;

a model of a representative charging circuit configured to simulate the initial charging of the battery and having a capacitor model configured to simulate charging to a first voltage;

a model of a representative electrochemical reaction circuit comprising;

a plurality of capacitor models configured to simulate the charging and discharging of the battery due to internal chemical reactions and configured to simulate charging to a second voltage;

a plurality of resistor models for simulating the resistance of the battery;

a model of a representative voltage drop circuit including a resistor model and a capacitor model configured to simulate capacitive charging and discharging of the battery and configured for simulating charging to a third voltage;

wherein the battery characterization system is implemented through a computer-based simulation.

33. The battery characterization system of claim 32 wherein the first voltage is at least about 11 volts, the second voltage is at least about 2 volts, and the third voltage is at least about 13 volts.

34. The battery characterization system of claim 32 wherein the model of a representative charging circuit comprises a double layer capacitance circuit model.

35. The battery characterization system of claim 32 wherein the model of a representative charging circuit includes a diode model for limiting the charge across the capacitor model of the charging circuit.

36. The battery characterization system of claim 32 wherein the computer-based simulation comprises software configured to run on at least one of a controller, a computer, and a microprocessor.

37. The battery characterization system of claim 32 one the plurality of the resistor models simulates an ionic resistance of the battery and another of the plurality of resistor models simulates an electrical resistance of the battery.

38. The battery characterization system of claim 32 further comprising means for simulating a slope of the open circuit voltage of the battery versus the relative state of charge of the battery due to at least one of time and temperature.

39. A method for making an equivalent electrical circuit model of a lead-acid battery comprising:

determining Peukert'"'"'s slope for the battery;

determining the nominal capacitance of the battery;

selecting a plurality of capacitors for the electrical circuit model based on the Peukert'"'"'s slope and the nominal capacitance of the battery.