Ultrasonic electrolyte sensor

• US 9,548,520 B2
• Filed: 05/08/2013
• Issued: 01/17/2017
• Est. Priority Date: 05/11/2012
• Status: Active Grant

• Current Assignee: Vertiv Corporation (Vertiv Holdings Co.)
• Original Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Inventors: Popken, David, Martinez, Juan, Deveau, Edward W., Stewart, David
• Primary Examiner(s): West, Paul
• Application Number:
  US13/889,593
• Publication Number:
  US 20130302655A1
• Time in Patent Office: 1,350 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01F 23/296 Acoustic waves
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: H01M 10/121 Valve regulated lead acid batteries [VRLA]
• CPC Class Codes: H01M 10/484 for measuring electrolyte level, electrolyte density or electrolyte conductivity
• CPC Class Codes: H01M 50/569 Constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals battery terminal connectors with integrated measuring arrangements G01R31/364
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A system is disclosed for monitoring an electrolyte level in a battery cell and generating an indication of a fault condition when the electrolyte level drops below a predetermined acceptable level. The system may make use of a controller, an ultrasonic transmit circuit for transmitting an ultrasonic signal into an interior area of the battery cell, and an ultrasonic receive circuit for receiving the ultrasonic signal after it has been reflected from the interior area of the battery cell. The controller may use the reflected ultrasonic signal and a predetermined calibration signal representing the predetermined acceptable level of the electrolyte to determine when the electrolyte level has dropped below the predetermined acceptable level.

Claims

1. A system for monitoring an electrolyte level in a battery cell and generating an indication of a fault condition when the electrolyte level drops below a predetermined acceptable level, the system comprising:

a housing adapted to be fixedly secured to an exterior surface of the battery cell;

a controller housed in the housing;

an ultrasonic transmitter circuit, housed in the housing, for transmitting an ultrasonic signal into an interior area of the battery cell;

an ultrasonic receive circuit, housed in the housing, for receiving the ultrasonic signal after it has been reflected from the interior area of the battery cell; and

the controller configured to use the reflected ultrasonic signal and a predetermined calibration signal representing the predetermined acceptable level of the electrolyte to determine when the electrolyte level has dropped below the predetermined acceptable level; and

wherein the controller is configured to obtain a plurality of calibration data samples to construct a calibration signature, and to obtain a plurality of test data samples to construct a test signature, and to compare the calibration signature with the test signature to determine if the electrolyte level is at least at the predetermined acceptable level.

2. The system of claim 1, wherein the reflected ultrasonic signal has a magnitude that varies depending on whether the transmitted ultrasonic signal impinges an interface comprised of:

a case of the battery cell and the electrolyte; and

a case of the battery cell and air.

3. The system of claim 1, wherein the controller is further configured to

average a series of the calibration data samples to obtain a plurality of averaged calibration data samples that are used to construct the calibration signature corresponding to the predetermined acceptable level of the electrolyte.

4. The system of claim 3, wherein the controller is configured to implement a test procedure to use the ultrasonic transmit and ultrasonic receive circuits to:

obtain a series of test data samples in response to a series of ultrasonic signal bursts; and

to average the obtained series of test data samples to obtain a plurality of averaged test data samples that are used to construct a test signature corresponding to an actual level of the electrolyte in the battery cell.

5. The system of claim 1, further comprising:

a light emitting diode (LED), and the controller configured to generate a signal to illuminate the LED when the electrolyte level is detected to be below the predetermined acceptable level; and

an input port and an output port for enabling the controller to communicate with a remote subsystem.

6. The system of claim 1, wherein the ultrasonic receive circuit includes an echo detection circuit for detecting and removing an echo to the reflected ultrasonic signal.

7. A system for monitoring an electrolyte level in a battery cell and generating an indication of a fault condition when the electrolyte level drops below a predetermined acceptable level, the system comprising:

a housing configured to be fixedly secured to an exterior surface of the battery cell;

a microcontroller housed in the housing;

a transmit ultrasonic circuit, housed in the housing, for transmitting ultrasonic signal pulses into an interior area of the battery cell;

a receive ultrasonic circuit, housed in the housing, for receiving the ultrasonic signal pulses after the ultrasonic signal pulses have been reflected from the interior area of the battery cell;

the microcontroller configured to;

convert each one of the reflected ultrasonic signal pulses into a calibration data sample during a calibration procedure to construct a calibration signature waveform representing the predetermined acceptable level of the electrolyte;

convert each one of the reflected ultrasonic signal pulses into a test data sample during a test procedure to construct a test signature waveform, which is representative of a real time electrolyte level within the battery cell;

to use the test and calibration signature waveforms to detect, in real time, when the electrolyte level within the battery cell has dropped below the predetermined acceptable level.

8. The system of claim 7, wherein the microcontroller comprises an analog-to-digital converter for converting each said reflected ultrasonic signal pulse, obtained subsequent to each said transmitted ultrasonic signal pulse, into a digital value, to be used in constructing at least one of the calibration and test signature waveforms.

9. The system of claim 8, further comprising a control for enabling a user to initiate the calibration procedure to obtain the calibration signature waveform.

10. The system of claim 9, wherein the control comprises a pushbutton for providing a signal to the microcontroller to initiate the calibration procedure.

11. The system of claim 7, further comprising an electrical input port and an output port both in communication with the microcontroller.

12. The system of claim 7, further comprising a light emitting diode (LED) responsive to a signal from the microcontroller to provide a visual warning to a user when the electrolyte level is detected to have fallen below the predetermined acceptable level.

13. A method for monitoring an electrolyte level in a battery cell and generating an indication of a fault condition when the electrolyte level drops below a predetermined acceptable level, the method comprising:

transmitting a first plurality of ultrasonic signals from within a housing, wherein the housing is fixedly secured to the battery cell, and receiving a first plurality of reflected ultrasonic signals;

using the first plurality of reflected ultrasonic signals to construct a calibration signature representative of a condition where the electrolyte level is at least at a predetermined acceptable level;

transmitting a second plurality of ultrasonic signals and receiving a second plurality of reflected ultrasonic signals;

using the second plurality of reflected ultrasonic signals to construct a test signature representative of an actual level of the electrolyte within the battery cell; and

using the calibration and test signatures to determine when the electrolyte level in the battery cell drops below the predetermined acceptable level.

14. The method of claim 13, wherein said using the calibration and test signatures comprises making at least one comparison of the calibration and test signatures.

15. The method of claim 14, wherein said making at least one comparison comprises making a plurality of comparisons.

16. The method of claim 14, wherein:

said constructing the calibration signature comprises converting ones of the first plurality of reflected ultrasonic signals to first digital values to construct a calibration signal waveform; and

said constructing the test signature comprises converting ones of the second plurality of reflected ultrasonic signals to second digital values to construct a test signal waveform.

17. The method of claim 16, further comprising:

averaging the first digital values to create a first plurality of averaged data samples; and

averaging the second digital values to create a second plurality of averaged data samples; and

wherein the making a comparison comprises making a sequence of comparisons of the specific ones of the first plurality of averaged data values with specific ones of the second plurality of average data values.

18. A system for monitoring an electrolyte level in a battery cell and generating an indication of a fault condition when the electrolyte level drops below a predetermined acceptable level, the system comprising:

a housing adapted to be fixedly secured to an exterior surface of the battery cell;

a controller housed in the housing;

an ultrasonic transmitter circuit, housed in the housing, for transmitting an ultrasonic signal into an interior area of the battery cell;

an ultrasonic receive circuit, housed in the housing, for receiving the ultrasonic signal after it has been reflected from the interior area of the battery cell;

the controller configured to use the reflected ultrasonic signal and a predetermined calibration signal representing the predetermined acceptable level of the electrolyte to determine when the electrolyte level has dropped below the predetermined acceptable level;

wherein the controller is configured to implement a calibration procedure to use the ultrasonic transmit and ultrasonic receive circuits to;

obtain a series of calibration data samples in response to a series of ultrasonic signal bursts; and

to average the obtained series of calibration data samples to obtain a plurality of averaged calibration data samples that are used to construct a calibration signature corresponding to the predetermined acceptable level of the electrolyte.