APPARATUS AND METHODS FOR BATTERY MONITORING USING DISCHARGE PULSE MEASUREMENTS

• US 20160291089A1
• Filed: 03/30/2015
• Published: 10/06/2016
• Est. Priority Date: 03/30/2015
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Arumugam, Balakrishnan, Shendurnikar, Mayuresh Arun, Dayma, Arti, Burgess, Webb L., Al-Atat, Hassan
• Granted Patent: US 9,983,266 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Methods include determining first and second voltages of a battery before and after a load interval, determining a current through the battery during the load interval, and determining a status of the battery from the determined first and second voltages and the determined current. The load interval may include an interval during which a discharge pulse is applied to the battery, and the first and second voltages may be voltages when the battery is open circuited. The first voltage may be determined before the battery transitions from an open-circuited state to a pulse discharge state, and the second voltage may be determined after the battery transitions from the pulse discharge state to the open-circuited state. Corresponding battery monitoring apparatus and computer program products are also described.

Claims

1. A method comprising:

determining first and second voltages of a battery before and after a load interval;

determining a current through the battery during the load interval; and

determining a status of the battery from the determined first and second voltages and the determined current.

2. The method of claim 1, wherein the load interval comprises an interval during which a discharge pulse is applied to the battery, and wherein the first and second voltages are voltages when the battery is open circuited.

3. The method of claim 2, wherein the first voltage is determined before the battery transitions from an open-circuited state to a pulse discharge state.

4. The method of claim 3, wherein the second voltage is determined after the battery transitions from the pulse discharge state to the open-circuited state.

5. The method of claim 1:

wherein determining first and second voltages of the battery before and after the load interval comprises determining the first voltage under a first load condition;

wherein the method further comprises transitioning the battery from the first load condition to a second load condition after determining the first voltage;

wherein determining the current through the battery during the load interval comprises determining the current under the second load condition;

wherein the method further comprises transitioning the battery from the second load condition to the first load condition; and

wherein determining first and second voltages of the battery before and after the load interval further comprises determining the second voltage under the first load condition.

6. The method of claim 5, wherein substantially more current is drawn from the battery under the second load condition that under the first load condition.

7. The method of claim 6, wherein the first load condition comprises an open circuit condition and wherein the second loading condition comprises a pulse discharge condition.

8. The method of claim 1, wherein determining a status of the battery from the determined first and second voltages and the determined current comprises determining a resistance of the battery from the determined first and second voltages and the determined current.

9. The method of claim 8, wherein determining a resistance of the battery from the determined first and second voltages and the determined current comprises a dividing a difference between the determined first and second voltages by the determined current.

10. The method of claim 1, wherein the battery is a valve-regulated lead acid (VRLA) battery and wherein the load interval comprises an interval of a discharge pulse sufficient to cause the battery to exit an equilibrium state.

11. The method of claim 10, wherein the discharge pulse is in a range from about 1 times the ampere-hour rating of the battery to about 15 times the ampere-hour rating of the battery.

12. A computer program product comprising computer program code embodied in a non-transitory computer-readable medium and configured to be executed on a data processing apparatus to perform the method of claim 1.

13. An apparatus comprising:

an input port configured to be coupled to a battery;

a load circuit coupled to the input port, configured to selectively couple a load to the input port; and

a control circuit coupled to the input port and the load circuit and configured to couple the load to the input for a load interval, to determine first and second voltages at the input port before and after the load interval, and to determine a current through the battery during the load interval.

14. The apparatus of claim 13, wherein the control circuit is further configured to determine a status of the battery from the determined first and second voltages and the determined current.

15. The apparatus of claim 13, wherein the control circuit is configured to determine a resistance of the battery from the determined first and second voltages and the determined current by dividing a difference between the first and second voltages by the determined current.

16. The apparatus of claim 15, wherein the load circuit, the current sensor and the control circuit are combined in a battery monitoring module configured to communicate with an external controller and to operate the load circuit and provide information regarding the determined resistance to the external controller responsive to a control input from the external controller.

17. The apparatus of claim 15, wherein the control circuit is further configured to determine a Coup de Fouet characteristic of the battery.

18. The apparatus of claim 13:

wherein the load circuit comprises a switch configured to selectively couple and decouple first and second terminals of the input port responsive to a switch control signal; and

wherein the control circuit comprises;

a current sensor configured to be coupled in series with the input port;

a voltage sensor coupled in parallel with the input port;

an analog to digital converter (ADC) circuit coupled to the current sensor and the voltage sensor; and

a processor coupled to the ADC circuit and configured to generate the switch control signal.

19. The apparatus of claim 18, wherein the current sensor is coupled in series with the switch.

20. The apparatus of claim 18, wherein the voltage sensor comprises a voltage divider.

21. The apparatus of claim 20, wherein the control circuit further comprises a difference amplifier circuit having a first input coupled to the voltage divider, a second input coupled to a reference voltage source, and an output coupled to an input of the ADC circuit.