STATE OF CHARGE BATTERY MONITORING

• US 20160114696A1
• Filed: 10/23/2015
• Published: 04/28/2016
• Est. Priority Date: 10/23/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: EIFERT, Mark, FRICKE, Birger
• Granted Patent: US 10,889,197 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 53/20 characterised by converters located in the vehicle
• CPC Class Codes: B60L 53/665 Methods related to measuring, billing or payment
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• 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 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/14 Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

Methods for monitoring the state of charge of a battery of a motor vehicle are disclosed in which the battery current is determined at moments at which the battery charging voltage has decreased to a defined limit value. The battery current thus determined is transmitted to an evaluation unit, which generates an alarm signal if no discharge of the battery is measured by means of the determined battery current in a defined period. The limit value for the decrease of the battery charging voltage is selected such that the algorithm as a result can identify whether the state of charge of a battery lies above or below a threshold above which a certain electrical functionality of the battery can be guaranteed.

Claims

1. A battery monitoring system comprising:

a controller programmed to decrease a battery charge voltage to a defined value such that a battery discharges in response to a state of charge (SOC) being greater than an SOC threshold and does not discharge in response to the SOC being less than the SOC threshold; and

an evaluation unit programmed to generate an alarm signal in response to an absence of discharge during the decrease.

2. The system as claimed in claim 1, wherein the controller is further programmed to perform the decreasing at scheduled intervals.

3. The system as claimed in claim 1, wherein the decreasing lasts for a predefined duration.

4. A method for monitoring the state of charge of a battery of a motor vehicle comprising:

transmitting to an evaluation unit battery current values determined at moments at which battery charging voltage is decreased to a defined limit value; and

generating by the evaluation unit an alarm signal if no discharge of the battery is measured via the determined battery current values in a defined monitoring period, wherein the defined limit value is selected such that the battery discharges when a state of charge of the battery is above a defined threshold and does not discharge when the state of charge is below the defined threshold.

5. The method as claimed in claim 4, wherein the battery current values are determined indirectly by measuring output current of a current source via which the battery is charged.

6. The method as claimed in claim 5, wherein the current source is a generator or a DCDC converter of the motor vehicle.

7. The method as claimed in claim 4, wherein the battery charging voltage is increased on account of a charging strategy if defined conditions are present, and the battery charging voltage is decreased to the defined limit value when the defined conditions are no longer present, the battery current values then being transmitted to the evaluation unit, which generates an alarm signal if no discharge of the battery is measured via the determined battery current values in a defined monitoring period.

8. The method as claimed in claim 7, wherein the defined conditions include efficiency of energy conversion of a drivetrain of the motor vehicle exceeding a threshold efficiency or conditions for regenerative braking.

9. The method as claimed in claim 4, wherein the battery charging voltage is decreased in accordance with a schedule at regular intervals to the defined limit value, the battery current values then being transmitted to the evaluation unit, which generates an alarm signal if no discharge of the battery is measured via the determined battery current values in a predefined monitoring period.

10. The method as claimed in claim 4, wherein a measure for changing battery situation is introduced by a system of the motor vehicle when the evaluation unit generates an alarm signal.

11. The method as claimed in claim 10, wherein a measure for changing the battery situation includes initiation of a charging process of the battery to a maximum state of charge.

12. The method as claimed in claim 10, wherein within a charging strategy for the battery, in which a switch is made in accordance with a schedule at regular intervals between trickle charging and equalization charging, an unscheduled change from trickle charging to equalization charging is initiated.

13. The method as claimed in claim 4, wherein the monitoring period is a fixedly defined value or is adapted continuously to a current state of the battery.

14. A method of monitoring a vehicle battery comprising:

by a controller,

decreasing a charge voltage of the battery to a defined value such that the battery discharges in response to a state of charge (SOC) of the battery being greater than an SOC threshold and does not discharge in response to the SOC being less than the SOC threshold, and

generating an alarm signal in an absence of battery discharge during a monitoring period.

15. The method as claimed in claim 14, wherein the decreasing is performed at scheduled intervals.

16. The method as claimed in claim 14, wherein a duration of the monitoring period is predefined.

17. The method as claimed in claim 14, wherein a duration of the monitoring period is based on a state of the battery.