System and method for calibrating battery state of charge

• US 10,391,878 B2
• Filed: 10/09/2014
• Issued: 08/27/2019
• Est. Priority Date: 10/09/2014
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Zhang, Jiucai, Hicks, Jr., Charles Clarence, Liu, Sam T., Kaucic, Robert A., Mao, Leng
• Primary Examiner(s): Godo, Olatunji A
• Application Number:
  US14/510,306
• Publication Number:
  US 20160101708A1
• Time in Patent Office: 1,783 Days
• Field of Search: 320128
• CPC Class Codes: B60L 53/00 Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• 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 90/14 Plug-in electric vehicles

Abstract

The present disclosure is directed to a system and method for calibrating state-of-charge (SOC) of an energy storage device. The method includes monitoring, via a battery management system, at least one of an accumulated capacity of the energy storage device after a first SOC calibration or a time period after the first SOC calibration. Another step includes determining, via the battery management system, whether at least one of the accumulated capacity or the time period is above a predetermined threshold. If at least one of the accumulated capacity or the time period is above a predetermined threshold, then the method includes charging, via the battery management system, the energy storage device for a specified duration until the energy storage device reaches a second SOC calibration.

Claims

1. A method for calibrating state-of-charge (SOC) of an energy storage device, the method comprising:

monitoring, via a battery management system, an accumulated capacity of the energy storage device after each top-of-charge (TOC) reset and a time period after each TOC reset, each TOC reset comprising the SOC of the energy storage device being equal to 100% full capacity during recharge when a certain battery condition is reached, the battery condition comprising at least one of a current, a resistance, or a voltage of the energy storage device;

determining, via the battery management system, whether the accumulated capacity or the time period after each TOC reset is above a predetermined threshold; and

if at least one of the accumulated capacity or the time period after each TOC reset is above a predetermined threshold, charging, via the battery management system, the energy storage device for a specified duration until the energy storage device reaches another TOC reset.

2. The method of claim 1, further comprising monitoring the accumulated capacity by monitoring a total ampere-hours discharged by the energy storage device.

3. The method of claim 1, further comprising monitoring the time period after each TOC reset via one or more sensors, wherein the one or more sensors comprise at least one of a clock, a timer, or a counter.

4. The method of claim 1, wherein the predetermined threshold comprises a value greater than at least one of a rated capacity of the energy storage device or a time value that is indicative of a failure of the energy storage device to reach the TOC reset.

5. The method of claim 1, wherein the SOC of the energy storage device comprises a percentage of a full capacity of the energy storage device that is available for discharge.

6. The method of claim 1, wherein the energy storage device comprises at least one of a lithium ion battery, a sodium nickel chloride battery, a sodium sulfur battery, a nickel metal hydride battery, a nickel cadmium battery, or a fuel cell.

7. The method of claim 1, wherein the energy storage device and the battery management system are components of an electric vehicle.

8. A system for calibrating state-of-charge (SOC) of an energy storage device, the system comprising:

one or more sensors configured to monitor an accumulated capacity of the energy storage device after a first each top-of-charge (TOC) reset and a time period after the first TOC reset, the first TOC reset comprising the SOC of the energy storage device being equal to 100% full capacity during recharge when a certain battery condition is reached, the battery condition comprising at least one of a current, a resistance, or a voltage of the energy storage device; and

a controller configured to perform one or more operations, the one or more operations comprising;

determining whether the accumulated capacity or the time period after the first TOC reset is above a predetermined threshold; and

if at least one of the accumulated capacity or the time period after the first TOC reset is above the predetermined threshold, charging the energy storage device for a specified duration until the energy storage device reaches a second TOC reset.

9. The system of claim 8, wherein the accumulated capacity is based on a total ampere-hours discharged by the energy storage device.

10. The system of claim 8, further comprising monitoring the time period after the first TOC reset via one or more sensors, wherein the one or more sensors comprise at least one of a clock, a timer, or a counter.

11. The system of claim 8, wherein the predetermined threshold comprises a value greater than at least one of a rated capacity of the energy storage device or a time value that is indicative of a failure of the energy storage device to reach the first TOC reset.

12. The system of claim 8, wherein the energy storage device comprises at least one of a lithium ion battery, a sodium nickel chloride battery, a sodium sulfur battery, a nickel metal hydride battery, a nickel cadmium battery, or a fuel cell.