Method and apparatus for reducing battery passivation in a meter-reading module

• US 8,847,785 B2
• Filed: 05/05/2011
• Issued: 09/30/2014
• Est. Priority Date: 05/05/2011
• Status: Active Grant

• Current Assignee: Sensus USA Incorporated (Xylem, Inc.)
• Original Assignee: Sensus USA Incorporated (Xylem, Inc.)
• Inventors: Heath, Nicholas
• Primary Examiner(s): Wu, Daniel
• Assistant Examiner(s): Haile, Benyam
• Application Number:
  US13/101,203
• Publication Number:
  US 20120280830A1
• Time in Patent Office: 1,244 Days
• Field of Search: 340/636, 340/870.02, 340/636.19, 320/100, 320/129, 320/130, 320/131
• US Class Current: 340/870.02
• CPC Class Codes: G01D 4/002 Remote reading of utility meters
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 6/50 Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 6/5044 Cells or batteries structurally combined with cell condition indicating means
• CPC Class Codes: H01M 6/5088 Initial activation; predischarge; Stabilisation of initial voltage
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

The teachings herein disclose a method and apparatus for preventing excessive battery passivation in an electronic meter-reading module. The module operates in a low-power state most of the time. The low-power state is interrupted at defined transmit times, wherein the module temporarily turns on or otherwise activates an included communication transmitter, for the transmission of data to a remote node reachable through a wireless communication network. Because of its low current draw during the times between data transmissions, the module'"'"'s battery is vulnerable to passivation layer buildup. Advantageously, however, the module is configured to perform dummy activations of its transmitter at times other than the defined transmit times, e.g., in the intervals between data transmissions. These dummy activations are not for data transmission, but rather are temporary activations of the relatively high-power transmitter, for reducing passivation layer buildup on the battery in advance of a next data transmission.

Claims

1. A method of preventing excessive battery passivation in an electronic meter reading module that is powered from a battery, the method comprising:

collecting metering data from an associated meter on an ongoing basis using comparatively low-power circuitry that is powered from the battery;

transmitting the metering data to a remote node through a wireless communication network at defined transmit times using a relatively high-power communication transceiver that is also powered by the battery and activated temporarily during the transmit times; and

performing dummy activations of the communication transceiver at additional times other than the defined transmit times, not for transmitting metering data but rather for depassivating the battery.

2. The method of claim 1, wherein performing said dummy activations comprises performing one or more dummy activations in each interval of time between periodic data transmissions.

3. The method of claim 1, wherein performing said dummy activations includes deciding to perform or skip any given dummy activation in dependence on one or more of:

an elapsed time since a last data transmission or dummy activation;

an ambient temperature value or time-at-temperature value;

or a minimum observed battery voltage as measured during a last data transmission or dummy activation.

4. The method of claim 1, further comprising conditioning the performance of said dummy activations on ambient temperature, such that said dummy activations are performed when an ambient temperature value or time-at-temperature value exceeds a predetermined threshold, and are otherwise not performed.

5. The method of claim 1, wherein performing said dummy activations includes monitoring ambient temperature and performing dummy activations more frequently at higher temperatures and less frequently or not at all at lower temperatures.

6. The method of claim 1, wherein performing said dummy activations includes triggering a dummy activation responsive to detecting that ambient temperature at the electronic meter reading module increases a predetermined amount within a predetermined period of time.

7. The method of claim 1, wherein performing said dummy activations includes triggering a dummy activation before a next data transmission in response to detecting excessive battery voltage droop in conjunction with performing a prior data transmission or a prior dummy activation.

8. The method of claim 1, wherein performing said dummy activations comprises, for each said dummy activation, executing a battery depassivation routine that includes one or more dummy activations of a power amplifier in a communication transceiver.

9. The method of claim 8, wherein said battery depassivation routine comprises an iterative routine that conditionally performs more than one activation of the power amplifier in dependence on ambient temperature or time-at-temperature, in dependence on observing battery voltage behavior in association with each such activation of the power amplifier.

10. A method of preventing excessive battery passivation in an electronic meter-reading module that is powered from a battery, the method comprising:

operating in a low-power state for extended periods of time, and collecting or otherwise maintaining metering data from an associated meter while in the low-power state;

interrupting the low-power state at defined transmit times, by activating a communication transceiver, including a transmitter, for performing a data transmission;

interrupting the low-power state at additional times other than said defined transmit times, by activating the transmitter not for data transmission, but rather to reduce passivation layer buildup in the battery.

11. The method of claim 10, wherein interrupting the low-power state at said additional times comprises temporarily activating the transmitter during one or more times between said data transmissions.

12. An electronic meter reading module configured for battery-powered operation from a battery, said module comprising:

a controller configured to obtain metering data from an interface circuit associated with a meter; and

a communication transceiver configured to communicatively couple the module to a remote node reachable through a wireless communication network; and

wherein said controller is configured to;

turn on or otherwise activate the communication transceiver temporarily at defined transmit times, for transmission of said metering data or other information; and

perform dummy activations of a transmitter in said communication transceiver at additional times other than said defined transmit times, for depassivating the battery.

13. The module of claim 12, wherein said controller is configured to perform said dummy activations by performing one or more dummy activations in each interval of time between periodic data transmissions.

14. The module of claim 12, wherein said controller is configured to decide whether to perform or skip any given dummy activation in dependence on one or more of:

an elapsed time since a last data transmission or dummy activation;

an ambient temperature value or time-at-temperature value;

or a minimum observed battery voltage as measured by the controller for a last data transmission or dummy activation.

15. The module of claim 12, wherein said controller is configured to condition the performance of said dummy activations on ambient temperature, such that said dummy activations are performed when an ambient temperature value or time-at-temperature value exceeds a predetermined threshold, and are otherwise not performed.

16. The module of claim 12, wherein said controller is configured to perform said dummy activations based on monitoring ambient temperature and performing dummy activations more frequently at higher temperatures and less frequently or not at all at lower temperatures.

17. The module of claim 12, wherein said controller is configured to trigger a dummy activation responsive to detecting that ambient temperature at the electronic meter reading module increases a predetermined amount within a predetermined period of time.

18. The module of claim 12, wherein said controller is configured to trigger a dummy activation before a next data transmission in response to detecting excessive battery voltage droop in conjunction with performing a prior data transmission or a prior dummy activation.

19. The module of claim 12, wherein said controller is configured to perform said dummy activations based on, for each said dummy activation, executing a battery depassivation routine that includes temporarily turning on a power amplifier in the communication transceiver one or more times.

20. The module of claim 19, wherein said battery depassivation routine comprises an iterative routine wherein said controller is configured to conditionally perform more than one activation of the power amplifier in dependence ambient temperature or time-at-temperature, in dependence on observing battery voltage behavior in association with each such activations of the power amplifier.