Monitoring apparatus and method for battery power supply

• US 4,390,841 A
• Filed: 10/14/1980
• Issued: 06/28/1983
• Est. Priority Date: 10/14/1980
• Status: Expired due to Term

• Current Assignee: Purdue Research Foundation (Purdue University)
• Original Assignee: Purdue Research Foundation (Purdue University)
• Inventors: Martin, Harry L., Goodson, Raymond E.
• Primary Examiner(s): Tokar, Michael J.
• Application Number:
  US06/196,398
• Time in Patent Office: 987 Days
• Field of Search: 324/425-428, 324/433, 324/434, 364/483, 429/93
• US Class Current: 324/427
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/378 specially adapted for the type of battery or accumulator
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• 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

Abstract

A monitoring apparatus and method are disclosed for monitoring and/or indicating energy that a battery power source has then remaining and/or can deliver for utilization purposes as, for example, to an electric vehicle. A battery mathematical model forms the basis for monitoring with a capacity prediction determined from measurement of the discharge current rate and stored battery parameters. The predicted capacity is used to provide a state-of-charge indication. Self-calibration over the life of the battery power supply is enacted through use of a feedback voltage based upon the difference between predicted and measured voltages to correct the battery mathematical model. Through use of a microprocessor with central information storage of temperature, current and voltage, system behavior is monitored, and system flexibility is enhanced.

Claims

1. A monitoring device for a battery power supply, said device comprising:

input means adapted to receive a current signal from a battery power supply to be monitored;

first capacity means connected with said input means to receive said current signal therefrom and responsive thereto providing an output signal indicative of the used capacity of a said battery power supply then being monitored;

second capacity means connected with said input means to receive said current signal therefrom, said second capacity means providing predicted parameters dependent upon the diffusion characteristics of said battery power supply, and said second capacity means being responsive to said current signal and to said predicted parameters of said battery power supply to provide an output signal indicative of the predicted remaining capacity of a said battery power supply then being monitored; and

determining means connected with first and second capacity means to receive said outputs therefrom and responsive thereto providing an output signal indicative of the state-of-charge of said battery power supply then being monitored.

2. The device of claim 1 wherein said device includes second input means adapted to receive a voltage signal from said battery supply then being monitored, voltage prediction means connected with said determining means for providing a predicted voltage, and comparison means connected with said second input means and said voltage prediction means for providing an error signal indicative of the voltage error therebetween, said error signal being coupled to said second capacity means.

3. The device of claim 1 wherein said determining means includes a means for determining the state-of-discharge of said battery power supply being monitored.

4. The device of claim 3 wherein said determining means includes power correction means for correcting the signal produced indicative of state-of-discharge.

5. The device of claim 3 wherein said determining means includes means for determining the state-of-charge of said battery power supply being monitored from said state-of-discharge signal.

6. A device of claim 1 wherein said second capacity means is a mathematical predictive model.

7. The device of claim 1 wherein said device includes a microprocessor for determining used and predicted capacities and to determine said state-of-charge of said battery power supply.

8. The device of claim 1 wherein said device includes a state-of-charge meter for indicating said state-of-charge determined by said determining means.

9. The device of claim 1 wherein said device includes a state-of-power meter for indicating power deliverable by said battery power supply.

10. A monitoring device for a battery power supply, said device comprising:

input means adapted to receive a current signal from a battery power supply being monitored;

means connected with said input means for determining the used capacity of said battery power supply being monitored and providing an output indicative thereof;

means for establishing a battery predictive model of said battery power supply being monitored, said model providing an output indicative of the predicted capacity of said battery power supply being monitored with said predicted capacity being dependent upon the diffusion characteristics of said battery power supply;

means connected with said used capacity determining means and said battery predictive model for determining the state-of-charge of said battery power supply being monitored; and

means connected with said state-of-discharge determining means for determining therefrom the state-of-charge of said battery power supply monitored.

11. The device of claim 10 wherein said device includes means connected with said input means at said state-of-discharge determining means for predicting a voltage for said battery power supply being monitored, wherein said device includes second input means adapted to receive a voltage signal from said battery power supply being monitored, and wherein said device includes voltage comparison means connected with said second input means and said voltage prediction means for comparing the voltages received therefrom and providing an error output signal indicative of deviations therebetween, said error output signal being coupled to said battery predictive model means for calibration purposes.

12. A monitoring device for a battery power supply, said device comprising:

first input means adapted to receive a current signal from a battery power supply to be monitored;

means establishing a mathematical model of said battery power supply, said model being connected with said first input means to receive said current signal providing an output indicative of the predicted capacity of said battery power supply being monitored;

used capacity detecting means connected with said input means to receive said current input signal and providing an output signal indicative of the used capacity of said battery being monitored;

state-of-discharge determining means connected with said mathematical model and said used capacity determining means to receive said outputs therefrom and responsive thereto providing a signal indicative of the state-of-discharge of said battery power supply being monitored;

power correction means connected with said state-of-discharge means to receive said output signal therefrom;

state-of-charge means connected with said power correction means to provide an output signal indicative of the state-of-charge of said battery power supply being monitored;

second input means adapted to receive a voltage signal from said battery power supply being monitored;

voltage prediction means connected with said state-of-discharge determining means and providing a predicted voltage for said battery power supply being monitored; and

voltage comparison means connected with said second input means and said voltage prediction means and providing a voltage error signal that is coupled to said mathematical model for calibration purposes.