Method and system of modeling energy flow for vehicle battery diagnostic monitoring

• US 20070236181A1
• Filed: 04/06/2006
• Published: 10/11/2007
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Original Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Inventors: Palladino, James
• Granted Patent: US 7,498,772 B2
• Time in Patent Office: Days
• US Class Current: 320/130
• 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 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/379 for lead-acid batteries
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• 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 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A lead acid battery model suitable for programming on a motor vehicle body computer uses environmental and target battery operating variables for maintaining synchronization of the model with the target battery under actual operating conditions. The model includes a energy flow section with at least two integrators for simulating primary and recovery reservoirs of charge in the battery. An output voltage estimation signal provides a signal for comparison with measured battery voltage for synchronization. Capacity of the reservoirs is generated from manufacturer specifications measured against battery performance.

Claims

1. A system for modeling a target battery installed on a motor vehicle comprising:

a voltage sensor connected to provide measurements of voltage across the terminals of the target battery;

a current sensor coupled to provide measurements of battery current through the target battery;

a temperature sensor providing a measurement of a temperature expected to correspond to battery temperature; and

a vehicle body computer connected to receive the measurements of temperature, current and voltage and having a stored program implementing an energy flow model of the target battery, the energy flow module having at least two energy storage reservoirs including a primary energy storage integrator and at least a first secondary energy storage integrator, the stored program being responsive upon execution by the vehicle body computer for using the measurements to adjust the capacities of the primary and at least a first secondary energy storage integrator, to determine the state of charge of the primary energy storage integrator and said at least first secondary energy storage integrator and to predict the output voltage of the target battery.

2. A system for modeling a target battery as set forth in claim 1, further comprising:

a comparator taking the predicted output voltage and measured battery voltage as inputs for generating an error signal related to the difference between the inputs; and

a summer taking the error signal and the battery current as inputs and supplying an adjusted battery current as an input to the stored program indicating energy flow into or out of the target battery thereby synchronizing the energy flow model with observed battery operating variables.

3. A system for modeling a target battery as set forth in claim 2, the system further comprising:

the primary energy storage integrator of the energy flow model having a feedback loop with a first gain element and the first secondary energy storage integrator having a feedback loop with a second gain element;

the gains for the first and second gain elements being independently set.

4. A system for modeling a target battery as set forth in claim 3, the stored program further comprising:

a module for determining capacity of the primary and the first secondary energy storage integrators; and

a module for predicting output voltage of the target battery.

5. A system for modeling a target battery as set forth in claim 4, the stored program further comprising:

the primary energy storage integrator and the first secondary energy storage integrator providing a primary and a secondary state of charge indication, respectively; and

means for comparing the primary state of charge and the secondary state of charge for generating a state or recovery indication which is positively correlated with a diminishing difference between the indications of primary and secondary state of charge.

6. A system for modeling a target battery as set forth in claim 5, the stored program further comprising:

the module for predicting output voltage of the target battery receiving as inputs the measurement of battery current, the indication of primary state of charge and an exogenously supplied value for battery cold cranking amps and including an exogenously generated polarization voltage look up table which takes the measurement of battery current as an input argument, a source resistance look up table which takes the primary state of charge as an input argument and a no load voltage look up table which takes the primary state of charge as an input argument.

7. A system for modeling a target battery as set forth in claim 6, further comprising the target battery being a lead acid battery.

8. A system for modeling a target battery as set forth in claim 6, the stored program further comprising:

a fault detection module coupled to receive the adjusted battery current, measured battery current, target battery output voltage and predicted output voltage as inputs for comparison to limits for generating a fault indication upon out of limit operation.

9. A control system for a motor vehicle equipped with an electrical battery plant, the control system comprising:

a voltage sensor connected to provide measurements of voltage across the terminals of the electrical battery plant;

a current sensor coupled to provide measurements of battery current through the electrical battery plant;

a temperature sensor providing a measurement of a temperature expected to correspond to battery temperature;

a vehicle body computer connected to receive the measurements of temperature, current and voltage and having a stored program implementing for monitoring battery condition;

the stored program energy providing a module for an energy flow model having at least a primary energy storage integrator from which energy flow into and out of the battery is indicated as occurring through and secondary energy storage integrator which exchanges energy with the primary energy storage integrator, the stored program further providing an electrical battery plant output voltage prediction module and a module for adjusting electrical storage capacities of the primary and secondary energy storage integrators; and

the stored program being responsive upon execution by the vehicle body computer for using the measurements to adjust the capacities of the primary and at least first secondary energy storage integrators, to determine the state of charge of the primary energy storage integrator and the secondary energy storage integrator and to predict the output voltage of the electrical battery plant.

10. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 9, the stored program further comprising:

a comparator taking the predicted output voltage and the measurement of electrical battery plant voltage as inputs for generating an error signal related to the difference between the inputs; and

a summer taking the error signal and the battery current as inputs and supplying an adjusted battery current as an input to the module for modeling energy flow of the electrical battery plant.

11. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 10, the stored program further comprising:

the primary energy storage integrator of the energy flow model having a feedback loop with a first gain element and the first secondary energy storage integrator having a feedback loop with a second gain element;

the gains for the first and second gain elements being exogenously supplied.

12. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 11, the stored program further comprising:

a module for determining capacity of the primary and the first secondary energy storage integrators; and

a module for predicting output voltage of the electrical battery plant.

13. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 12, the stored program further comprising:

the primary energy storage integrator and the first secondary energy storage integrator providing a primary and a secondary state of charge indication, respectively; and

means for comparing the primary state of charge and the secondary state of charge for generating a state or recovery indication which is positively correlated with a diminishing difference between the indications of primary and secondary state of charge.

14. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 13, the stored program further comprising:

the module for predicting output voltage of the electrical battery plant receiving as inputs the measurement of battery current, the indication of primary state of charge and an exogenously supplied value for battery cold cranking amps and including an exogenously generated polarization voltage look up table which takes the measurement of battery current as an input argument, a source resistance look up table which takes the primary state of charge as an input argument and a no load voltage look up table which takes the primary state of charge as an input argument.

15. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 14, further comprising the electrical battery plant being a lead acid battery.

16. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 14, the stored program further comprising:

a fault detection module coupled to receive the adjusted battery current, measured battery current, electrical battery plant output voltage and predicted output voltage as inputs for comparison to limits for generating a fault indication upon out of limit operation.