System and method for monitoring a vehicle battery

• US 6,424,157 B1
• Filed: 07/20/1999
• Issued: 07/23/2002
• Est. Priority Date: 07/20/1998
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc., Samsung Electronics Co. Ltd.
• Original Assignee: Alliedsignal Inc.
• Inventors: Vernick, Douglas, Palanisamy, Thirumalai G., Gollomp, Bernard P.
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): SUNDARAM, T R
• Application Number:
  US09/357,542
• Time in Patent Office: 1,099 Days
• Field of Search: 324/430, 324/425, 324/426, 324/427, 324/431, 324/433, 320/48, 320/132
• US Class Current: 324/430
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/427 Voltage
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/662 Temperature
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

A system and method for monitoring and reporting on the condition of a vehicle battery which measures battery voltage and current drain during engine start, and computes the battery dynamic internal resistance (IR) and dynamic polarization resistance (PR) from these quantities. Also, the quiescent voltage (QV) of the battery, which is that measured while the vehicle electrical system has a current drain of from 0 to a predetermined amount, is measured and the battery state-of-charge (SoC) is computed from the QV. From these quantities, calculations are made of quantities such as rate of change of dynamic IR and PR to analyze battery condition, rate of change of QV and SoC to predict the time during which the battery can still start the engine, and minimum ambient temperature at which the battery will be able to start the engine, and of other conditions. Appropriate messages can be displayed of the measured and computed quantities as well as warnings to advise the driver of various real and potential problems related to the battery, its cables and components of its charging system.

Claims

1. A system for monitoring the condition of a battery installed in a vehicle having an engine, said system comprising:

a voltage sensor for determining the voltage of the battery at the time of starting of the vehicle engine;

a current sensor for determining the current drain of the battery at said time of starting of the engine; and

computer means for computing the rate of change of the battery dynamic internal resistance (IR) and the rate of change of the battery dynamic polarization resistance (PR) based on determinations of voltage and current by said voltage sensor and said current sensor at different times of vehicle engine start, said computer means further including means responsive to an increasing dynamic IR and an increasing dynamic PR for producing an indication of low electrolyte in the battery.

2. A system for monitoring the condition of a battery installed in a vehicle having an engine, said system comprising:

a voltage sensor for determining the voltage of the battery at the time of starting of the vehicle engine;

a current sensor for determining the current drain of the battery at said time of starting of the engine; and

computer means for computing the rate of change of the battery dynamic internal resistance (IR) and the rate of change of the battery dynamic polarization resistance (PR) based on determinations of voltage and current by said voltage sensor and said current sensor at different times of vehicle engine start, said computer means further including means responsive to said dynamic IR increasing and said dynamic PR decreasing for initiating an indication of at least one of possible battery terminal corrosion or loose connection of a cable connecting a terminal of the battery to the vehicle electrical system.

3. A system for monitoring the condition of a battery in a vehicle having an engine, said system comprising:

a voltage sensor for determining the voltage of the battery at the time of starting of the vehicle engine;

a current sensor for determining the current drain of the battery at said time of starting of the engine; and

computer means for computing the rate of change of the battery dynamic internal resistance (IR) and the rate of change of the battery dynamic polarization resistance (PR) based on determinations of voltage and current by said voltage sensor and said current sensor at different times of engine start, said computer means further including means responsive to said dynamic IR decreasing and said dynamic PR increasing for initiating an indication of the battery being unable to start the engine below a certain ambient temperature.

4. The system as in claim 3 wherein said computer means includes storage means for storing data of the battery output as a function of its dynamic IR and temperature;

and

said computer means computing a low temperature limit at which the battery will be unable to start the engine on the basis of the dynamic IR and said stored data.

5. A system for monitoring and reporting on the condition of a battery installed in a vehicle having an engine and an ignition, said system comprising:

a sensor for determining the voltage across the battery terminals under conditions of current drain of the vehicle electrical system to determine the quiescent voltage current drain value (QV); and

means for calculating the battery state-of-charge (SOC) on the basis of the measured QV.

6. A system as in claim 5 further comprising:

a voltage sensor for determining the voltage of the battery at the time of starting of the vehicle engine;

a current sensor for determining the current drain of the battery at said time of starting of the engine; and

wherein said calculating means includes mean for computing at least one of the battery dynamic internal resistance (IR) and the battery internal dynamic polarization resistance (PR) on the basis of said determined voltage and current.

7. A system as in claim 5 further comprising:

a vehicle charging system; and

a sensor for determining if the vehicle ignition is off; and

wherein said calculating means further includes means for producing an indication of at least one of a possible vehicle battery charging system component problem and battery state-of-charge condition in response to a determination that the ignition is off.

8. A system as in claim 7 wherein said means for producing also compares QV relative to predetermined voltage values and determines the type of indication based on the result of the comparison.

9. A system as in claim 5 further comprising:

an ignition sensor to determine if the vehicle ignition is off;

a current sensor to sense the current drain of the vehicle electrical system; and

wherein said calculating means further includes means for producing an indication of the occurrence of an excessive current drain.

10. A system as in claim 9 wherein said calculating means further includes battery condition determining means responsive to a measured current drain greater than a predetermined value for a predetermined time period having elapsed since the ignition being cut off and QV being less than a predetermined voltage to produce an indication of at least one of then battery losing charge and the battery not being able to start the engine.

11. A system as in claim 10 wherein said predetermined voltage has first and second levels and said battery condition determining means produces the indication of the battery being unable to start the engine when QV is less than said second level, which second level is less than said first level.

12. A system as in claim 5 wherein said calculating means also indicates at least one of a decline rate of the SoC over a period of time and a decline of QV over a period of time and determines the time remaining during which the battery is still able to start the vehicle engine based on at least one of the computer SoC decline rate and QV decline rate.

13. A system as in claim 12 wherein said calculating means further includes means to compare the time remaining against a predetermined time period and to produce an indication when said predetermined time period has been exceeded.

14. A system for monitoring and reporting on the condition of a battery installed in a vehicle having an engine and an ignition, said system comprising:

a voltage sensor four determining the voltage across the battery terminals under conditions of current drain of the vehicle electrical system up to a predetermined current drain value (QV);

an ignition sensor to determine if the vehicle ignition is on;

a starter sensor to determine if the engine starter is on;

an engine sensor to determine if the engine is running a self sustaining speed; and

means for calculating the battery state of charge (SoC) on the basis of the measured QV, said calculating means including engine start up condition determining means for producing an indication that there is an engine start failure and the battery is losing charge in response to a determination of the ignition being on, a determination of the starter being off for more that a predetermined time, and a determination of the engine not being at a self-sustaining speed.

15. A system for monitoring and reporting on the condition of a battery installed in a vehicle having an engine, said system comprising:

a sensor for determining the voltage across the battery terminals under conditions of current drain of the vehicle during electrical system start up to determine quiescent voltage drain value (QV);

and means for calculating the battery state-of-charge (SoC) on the basis of the measured QV, said calculating means also indicating at least one of a decline rate of the SoC over a period of time and a decline rate of QV over a period of time and determining the time remaining during which the battery is still able to start the vehicle engine based on at least one of the computed SoC decline rate and QV decline rate, the time remaining based on the SoC decline rate being determined as $\mathrm{Time}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Remaining}=\frac{\left(\mathrm{SoC}-70\right)}{\mathrm{SoC}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{decline}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{rate}}.$

16. A system for monitoring and reporting on the condition of a battery installed in a vehicle having an engine, said system comprising:

a sensor for determining the voltage across the battery terminals under conditions of current drain of the vehicle electrical system up to a predetermined quiescent voltage current drain value (QV); and

means for calculating the battery state-of-charge (SoC) on the basis of the measured QV, said calculating means also indicating at least one of a decline rate of the SoC over a period of time and a decline rate of the QV over a period of time and determining the time remaining during which the battery is still able to start the vehicle engine based on at least one of the computed SoC decline rate and QV decline rate, the time remaining based on the QV decline rate being $\mathrm{Time}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{Remaining}=\frac{\mathrm{QV}-12.30}{\mathrm{QV}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{decline}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{rate}}.$

17. A method for monitoring the condition of a battery installed in a vehicle having an engine, said method comprising:

determining the voltage of the battery at the time of starting of the vehicle engine;

determining the current drain of the battery at said time of starting of the vehicle engine;

computing the battery dynamic internal resistance (IR) and battery dynamic polarization resistance (PR) on the basis of the voltage and current determined by voltage and current sensors;

computing the rate of change of dynamic IR and dynamic PR based on determinations of voltage and current at different times of vehicle engine start; and

producing an indication of a specific battery condition in response to said dynamic IR increasing or decreasing while said dynamic PR is increasing or decreasing.

18. A method as in claim 17 wherein said step of producing an indication of a specific battery condition comprises producing an indication of low electrolyte in a battery in response to increasing dynamic IR and increasing dynamic PR.

19. A method as in claim 17 wherein said step of producing an indication of a specific battery condition comprises initiating an indication of at least one of possible battery terminal corrosion or loose connection of a cable connecting a terminal of the battery to the vehicle electrical system in response to dynamic IR increasing and dynamic PR decreasing.

20. A method as in claim 17 wherein said step of producing an indication of a specific battery condition comprises initiating an indication of the battery being unable to start the engine below a certain ambient temperature in response to dynamic IR decreasing and dynamic IR increasing.

21. A method as in claim 20 further comprising:

storing data of the battery output as a function of its dynamic IR and temperature; and

computing a low temperature limit at which the battery will be unable to start the engine based on the current IR and the stored data.

22. A method for monitoring and reporting on the condition of a battery installed in a vehicle having a engine and an ignition comprising:

determining the voltage across the battery terminals under conditions of current drain of the vehicle electrical system to determine the current quiescent voltage drain value (QV); and

calculating the battery state-of-charge (SoC) on the basis of the measured QV.

23. A method as in claim 22 further comprising:

determining the voltage of the battery at the time of starting the vehicle engine;

determining the drain of the battery at said time of starting of the engine; and

computing at least one of the battery dynamic internal resistance (IR) and dynamic polarization resistance (PR) on the basis of said determined voltage and current drain.

24. A method as in claim 22 further comprising:

sensing if the vehicle ignition is off; and

producing an indication of at least one of a possible vehicle battery charging system component problem and battery state-of-charge condition in response to a determination that the ignition is off.

25. A method as in claim 24 further comprising:

comparing QV relative to predetermined voltage values and selecting the type of indication based on the result of the comparison.

26. A method as in claim 22 further comprising:

sensing if the vehicle ignition is off;

sensing the current drain of the vehicle electrical system; and

producing an indication of the occurrence of an excessive current drain.

27. A method as in claim 22 further comprising:

sensing if the vehicle ignition is off;

sensing the current drain of the vehicle electrical system; and

determining, responsive to a measured current drain greater than a predetermined value for a predetermined time period having elapsed since the ignition was sensed being off and QV being less than a predetermined voltage, to produce an indication of at least one of the battery losing charge and the battery not being able to start the engine.

28. A method as in claim 22 further comprising:

sensing if the vehicle ignition is on;

sensing if the engine starter is on;

sensing if the engine is running at a self-sustaining speed; and

producing an indication that there is an engine start failure and the battery is losing charge in response to a determination of the ignition being on, a determination of the starter being off for more than a predetermined time and a determination of the engine not being at a self-sustaining speed.

29. A method as in claim 22 further comprising:

calculating at least one of a decline rate of the SoC over a period of time and a decline rate of QV over a period of time; and

determining the time remaining during which the battery is still able to start the vehicle engine based on at least one of the computed SoC decline rate and the QV decline rate.

30. A method as in claim 29 further comprising:

comparing the time remaining against a predetermined time period and producing an indication when said predetermined time period has been exceeded.

31. A method as in claim 22 further comprising:

accumulating the total value of the quantity of discharge from the battery over a period of time.

32. A method as in claim 31 further comprising:

producing an indication of the battery not charging in response to accumulating the value of the quantity of discharge from the battery.