In-vehicle battery monitor

• US 7,999,505 B2
• Filed: 10/05/2004
• Issued: 08/16/2011
• Est. Priority Date: 11/03/1997
• Status: Expired due to Fees

• Current Assignee: Midtronics Incorporated
• Original Assignee: Midtronics Incorporated
• Inventors: Bertness, Kevin I.
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): BOATENG, ALEXIS ASIEDUA
• Application Number:
  US10/958,821
• Publication Number:
  US 20050068039A1
• Time in Patent Office: 2,506 Days
• Field of Search: 320/104, 320/103, 320/132, 320/110, 203/104, 203/106, 203/107, 203/155, 203/161, 203/162, 203/163, 203/164, 203/148, 203/149
• US Class Current: 320/104
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• 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 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00041 in response to measured battery parameters, e.g. voltage, current or temperature profile
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/163 with special means for initiating or limiting the excitation current
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An apparatus and a method of monitoring a battery in an automotive vehicle are provided. An output is provided which can be a relative output as a function of minimum and maximum parameters of the battery.

Claims

1. A battery monitor for use in monitoring a battery of an automotive vehicle comprising:

a voltage sensor configured to monitor a voltage across the battery applied to an electrical system of the vehicle;

a current sensor configured to monitor an electrical current through the battery and the electrical system of the vehicle;

a processor configured to measure a parameter of the battery based upon the sensed current and the sensed voltage, compare the measured parameter with a historical parameter obtained from a previous measurement and responsively identify that an original battery has been removed from the vehicle and that a replacement battery has been installed based upon a result of the comparison, measuring and responsively begin a learning process to learn a state of charge of the replacement battery by monitoring current and voltage during operation of the automotive vehicle.

2. The apparatus of claim 1 wherein the replacement of the battery is identified if the measured parameter is within 10% of the historical parameter.

3. The apparatus of claim 1 wherein the historical parameter is less then one month old.

4. The apparatus of claim 1 wherein the historical parameter is from a previous time the vehicle was operated.

5. The apparatus of claim 1 wherein in response to replacement of the battery the processor updates a stored parameter of the battery.

6. The apparatus of claim 1 wherein the microprocessor determines condition of the battery as a function of the stored parameter of the battery.

7. The apparatus of claim 1 wherein the parameter comprises a dynamic parameter.

8. The apparatus of claim 1, including:

an analog to digital converter configured to convert sensed current from the current sensor to a digital value;

a constant offset configured to reduce a quiescent current draw from the sensed current prior to digitizing the sensed current by the analog to digital converter.

9. The apparatus of claim 8 wherein the processor enters a sleep mode during periods of vehicle inactivity and is activated from the sleep mode if current is greater than at least the constant offset.

10. The apparatus of claim 8 wherein the constant offset has a first value during vehicle operation and a second value during vehicle inactivity.

11. The apparatus of claim 8 wherein the processor integrates digitized current values over time.

12. The apparatus of claim 8 the processor uses the constant offset for calculations of the digitized current is less than a threshold.

13. The apparatus of claim 1, including:

a communication link configured to couple to a data bus of the vehicle; and

wherein the processor is further configured to receive a signal from the data bus indicative of operation of an electrical component of the vehicle and responsively wake up from a sleep mode to monitor the electrical current through the battery using the current sensor.

14. The apparatus of claim 13 wherein the processor re-enters the sleep mode after operation of the electrical component has terminated.

15. The apparatus of claim 13 wherein the signal indicates a door of the vehicle has opened.