METHOD FOR DETERMINING THE CHARGE STATE OF A MOTOR VEHICLE BATTERY

• US 20100090660A1
• Filed: 10/08/2009
• Published: 04/15/2010
• Est. Priority Date: 10/13/2008
• Status: Active Grant

• Current Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Original Assignee: Dr. Ing. H.C.F. Porsche Ag, FWB Kunststofftechnik GmbH (Forvia SE)
• Inventors: Youssef, Sargon, Eger, Ulrich, Dyck, Alexander
• Granted Patent: US 8,222,859 B2
• Time in Patent Office: Days
• US Class Current: 320/153
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3835 involving only voltage measurements

Abstract

A method is provided for determining the charge state of a motor vehicle battery. An electrical voltage of the motor vehicle battery is detected and the electrical charge state of the motor vehicle battery is determined on the basis of the detected voltage of the motor vehicle battery. According to the method, the temperature of the motor vehicle battery is detected using a sensor that is separated spatially from the motor vehicle battery, and the charge state of the battery is determined on the basis of the detected voltage of the motor vehicle battery and on the basis of the detected temperature of the motor vehicle battery.

Claims

1. A method for determining the charge state of a motor vehicle battery, wherein an electrical voltage of the motor vehicle battery is detected and the electrical charge state of the motor vehicle battery is determined on the basis of the detected voltage of said motor vehicle battery, characterized in that the temperature of the motor vehicle battery is detected using a sensor that is separated spatially from the motor vehicle battery, and in that the charge state of the battery is determined on the basis of the detected voltage of the motor vehicle battery and on the basis of the detected temperature of the motor vehicle battery.

2. The method of claim 1, wherein the temperature of the motor vehicle battery is detected using a sensor external to the motor vehicle battery and assigned to a battery-charging device.

3. The method of claim 2, wherein the battery-charging device is in the interior of the motor vehicle.

4. The method of claim 1, wherein the temperature of the motor vehicle battery is detected using the sensor in a plurality of successive measurements, wherein, a temperature value which is measured by the sensor is determined as a temperature of the motor vehicle battery when the detected temperature values differ from one another within a permissible tolerance band.

5. The method of claim 1, wherein the voltage of the motor vehicle battery is detected using a sensor that is external to the motor vehicle battery and that is assigned to a battery-charging device.

6. The method of claim 5, wherein the battery-charging device is connected to an on-board electrical system of the motor vehicle.

7. The method of claim 1, wherein the electrical voltage of the motor vehicle battery is detected by acquiring a voltage measured value in a plurality of successive measurements, and wherein, a voltage measured value is determined as a voltage of the motor vehicle battery when the voltage measured values differ from one another within a permissible tolerance band.

8. The method of claim 1, wherein the electrical charge state of the motor vehicle battery is determined by means of a formula on the basis of the detected voltage of the motor vehicle battery and on the basis of the detected temperature of the motor vehicle battery.

9. The method of claim 1, wherein the electrical charge state of the motor vehicle battery is determined by a characteristic diagram on the basis of the detected voltage of the motor vehicle battery and on the basis of the detected temperature of the motor vehicle battery.

10. The method of claim 1, wherein the charge state of the motor vehicle battery is determined at time intervals on a motor vehicle with a switched-off drive unit.

11. The method of claim 10, wherein, the battery-charging device is activated to charge the motor vehicle battery if the charge state of the motor vehicle battery is determined to lower than a defined limiting value.

12. The method of claim 11, wherein, the battery-charging device is not activated if the charge state of the motor vehicle battery is higher than a defined limiting value.

13. A method for determining a charge state of a motor vehicle battery, comprising:

detecting voltage of the motor vehicle battery;

detecting a temperature of the motor vehicle battery using a sensor that is separated spatially from the motor vehicle battery; and

determining the charge state of the battery based on the detected voltage of the motor vehicle battery and on the detected temperature of the motor vehicle battery.

14. The method of claim 13, wherein the step of detecting the temperature of the motor vehicle battery comprises:

using the sensor to make a plurality of successive temperature measurements to obtain a plurality of successive detected temperature values;

determining whether the detected temperature values differ from one another within a permissible tolerance band; and

determining a temperature value measured by the sensor as a temperature of the motor vehicle battery when the detected temperature values differ from one another within the permissible tolerance band.

15. The method of claim 13, wherein the step of detecting voltage of the motor vehicle battery comprises detecting the voltage of the motor vehicle battery in a plurality of successive measurements to obtain a voltage measured value, and wherein the method further comprises:

determining whether the detected voltage measured values differ from one another within a permissible tolerance band; and

determining a measured voltage measured value as a voltage of the motor vehicle battery when the detected voltage measured values differ from one another within a permissible tolerance band.

16. The method of claim 13, wherein the electrical charge state of the motor vehicle battery is determined by a formula on the basis of the detected voltage of the motor vehicle battery and on the basis of the detected temperature of the motor vehicle battery.

17. The method of claim 13, wherein the electrical charge state of the motor vehicle battery is determined by a characteristic diagram on the basis of the detected voltage of the motor vehicle battery and on the basis of the detected temperature of the motor vehicle battery.

18. The method of claim 13, wherein the charge state of the motor vehicle battery is determined at time intervals on a motor vehicle with a switched-off drive unit.

19. The method of claim 13, wherein if the charge state of the motor vehicle battery which is lower than a defined limiting value, the battery-charging device is activated to charge the motor vehicle battery.

20. A motor vehicle, comprising:

a chargeable battery;

a voltage detector for detecting a voltage of the battery;

a temperature sensor spatially separated from the battery; and

a battery charging device connected to the battery, the voltage detector and the temperature sensor and independent of an electrical main supply, the battery charging device being configured for charging the battery when a charged state of the battery drops below a predetermined limiting value as determined the voltage of the battery detected by the voltage detector and the temperature sensed by the temperature sensor.