VEHICLE BATTERY STATE OF CHARGE INDICATOR

• US 20080254347A1
• Filed: 04/12/2007
• Published: 10/16/2008
• Est. Priority Date: 04/12/2007
• 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 7,652,448 B2
• Time in Patent Office: Days
• US Class Current: 429/90
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• 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: Y02E 60/10 Energy storage using batteries

Abstract

A system for modeling a battery installed on a motor vehicle including a crank started engine, a voltage sensor connected to provide measurements of battery voltage and a temperature sensor providing temperature measurements provides for correcting capacity of the battery starting from the battery'"'"'s rated capacity. A vehicle body computer implements the model through a stored program implementing an energy flow model of the target battery and stored data relating to model parameters including battery rated capacity and cranking current required for engine start over a temperature range. The stored program being responsive upon execution by the vehicle body computer for using the battery voltage measurements and temperature measurements during engine cranking to correct battery capacity.

Claims

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

a crank started engine;

a starter motor for the crank started engine connected for energization to the battery;

a voltage sensor connected to provide measurements of battery voltage;

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 and battery voltage and having a stored program implementing an energy flow model of the target battery and stored data relating to model parameters including battery rated capacity, battery corrected capacity and cranking current required for engine start over a temperature range, the stored program being responsive upon execution by the vehicle body computer for using the battery voltage measurements and temperature measurements during engine cranking and time to crank to generate updates of the corrected battery capacity.

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

a module for predicting battery voltage;

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 which is used in the calculation of updated battery capacity and which are supplied to the energy flow module for use in generating battery state of charge and battery state of recovery.

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

a virtual ammeter output using updated battery capacity, the error current and temperature as inputs.

4. A control system for a motor vehicle equipped with an electrical battery plant, a starter motor and a crank started engine, the control system comprising:

a voltage sensor connected to provide measurements of voltage of 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 and measured voltage and having a stored program for modeling battery condition and generating an estimated current flow to and from the electrical battery plant;

the stored program providing a module for an energy flow module generating battery state of charge and state of recovery information, a battery capacity calculation module providing estimated battery current, a model parameter module and a predicted voltage module, the battery capacity calculation module being responsive to an error signal generated from actual and predicted voltage, temperature and a previous estimate of battery capacity or an exogenously supplied value for battery capacity for generating an updated estimate of battery capacity and a current estimate of net battery current flow.

5. A control system for a motor vehicle equipped with an electrical battery plant as set forth in claim 4, further comprising:

an engine controller controlling the starter motor for crank starting the engine and indicating to the battery capacity calculation module the time required to start the engine;

the model parameter section including a table of battery current requirements for crank starting the engine over a range of temperatures;

the battery capacity calculation module being programmed to derive actual current delivered based on the time to start, the temperature and the table of battery current requirements and using the ratio of the actual current delivered to the error current for determining updated battery capacity.