Battery charging control methods and apparatus

• US 8,253,387 B2
• Filed: 04/24/2009
• Issued: 08/28/2012
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Newhouse, Vernon L., Marsh, Richard A., Johnson, Carol L., Groshek, Paul G.
• Primary Examiner(s): Berhanu, Samuel
• Application Number:
  US12/429,946
• Publication Number:
  US 20100270980A1
• Time in Patent Office: 1,222 Days
• Field of Search: 320/104, 320/150, 320/153, 320/144
• US Class Current: 320/150
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Embodiments include methods for charging a battery of an electrical system. The electrical system includes the battery, a battery charger, and a controller. The battery charger is adapted to produce an output power in response to a control signal from the controller. The controller is adapted to control a battery charging process by determining a temperature of the battery pack, determining a voltage setpoint for the battery charger based on the temperature, and providing the control signal to the battery charger. According to an embodiment, when the temperature of the battery exceeds a first temperature value, the battery charging process is temporarily suspended prior to satisfying a charging termination criterion. Determining the temperature of the battery is repeated, and when the temperature of the battery is less than a second temperature value, the battery charging process is resumed.

Claims

1. A method for charging a battery of an electrical system that includes the battery, a battery charger, and a controller, the method comprising the steps of:

determining a temperature of the battery;

determining an allowable state of charge of the battery based on the temperature, wherein the allowable state of charge is less than a maximum state of charge of the battery; and

determining a voltage setpoint based on the allowable state of charge; and

providing a charger control signal to the battery charger to cause an inverter system of the battery charger to convert alternating current (AC) power from an AC power source into direct current (DC) power at an output power that is provided to the battery, and that results in increasing an output voltage of the battery toward the voltage setpoint.

2. The method of claim 1, wherein determining the voltage setpoint comprises:

calculating the voltage setpoint as a function of the temperature.

3. The method of claim 1, wherein determining the voltage setpoint comprises:

determining the voltage setpoint from a table of temperature/setpoint values.

4. The method of claim 1, wherein determining the voltage setpoint comprises:

determining the voltage setpoint from a table of state of charge/setpoint values.

5. The method of claim 1, further comprising:

determining whether a charging termination criteria has been satisfied; and

when the charging termination criteria has been satisfied, terminating the process of charging the battery.

6. The method of claim 5, wherein the charging termination criteria is a criteria selected from a group that includes the battery having reached a maximum state of charge and a battery voltage having reached a maximum battery voltage.

7. A method for charging a battery of an electrical system that includes the battery, a battery charger, and a controller, the method comprising the steps of:

initiating a charging process to cause the battery charger to charge the battery;

determining a temperature of the battery;

determining an allowable state of charge of the battery based on the temperature, wherein the allowable state of charge is less than a maximum state of charge of the battery; and

determining a voltage setpoint based on the allowable state of charge;

providing a charger control signal to the battery charger to cause an inverter system of the battery charger to convert alternating current (AC) power from an AC power source into direct current (DC) power at an output power that is provided to the battery, and that results in increasing an output voltage of the battery toward the voltage setpoint;

when the temperature of the battery exceeds a first temperature value, temporarily suspending the battery charging process prior to satisfying a charging termination criterion;

repeating determining the temperature of the battery; and

when the temperature of the battery is less than a second temperature value, resuming the battery charging process.

8. The method of claim 7, wherein resuming the battery charging process comprises:

determining, based on the temperature, the voltage setpoint for the battery charger, wherein the voltage setpoint is less than a maximum battery voltage; and

controlling the battery charger to produce the output power that results in increasing the output voltage of the battery toward the voltage setpoint.

9. An electrical system comprising:

a high voltage (HV) energy storage system having a battery pack that stores electrical energy;

a battery charger including an inverter system that converts alternating current (AC) power from an AC power source into direct current (DC) power at an output power that is provided to the battery pack, wherein the output power is produced in response to a control signal that indicates a voltage setpoint for the battery pack; and

a controller that controls a battery charging process by determining a temperature of the battery pack, determining an allowable state of charge of the battery based on the temperature, wherein the allowable state of charge is less than a maximum state of charge of the battery; and

determining the voltage setpoint based on the allowable state of charge, and providing the control signal to the battery charge , and that results in increasing an out voltage of the battery pack toward the voltage setpoint.

10. The electrical system of claim 9, further comprising:

an alternating current (AC) power interface that provides a status signal to the controller, which indicates whether or not the AC power interface is electrically coupled with an external AC power source,

wherein the controller initiates the battery charging process in response to receiving the status signal.

11. The electrical system of claim 9, wherein the HV energy storage system further comprises:

one or more temperature sensors that provide temperature signals to the controller, wherein the controller uses the temperature signals to determine the temperature of the battery pack; and

a voltage sensor that provides voltage signals to the controller, which indicate a current voltage across terminals of the battery pack.

12. The electrical system of claim 9, wherein the battery pack produces a maximum output voltage across its terminals of 300 volts or more.

13. The electrical system of claim 9, wherein the battery pack produces a maximum output voltage across its terminals of 60 volts or more.

14. The electrical system of claim 9, wherein the temporarily suspends the battery charging process prior to satisfying a charging termination criteria, when the temperature of the battery pack exceeds a first temperature value, and resumes the battery charging process when the temperature of the battery pack is less than a second temperature value.

15. The electrical system of claim 9, wherein the controller temporarily suspends the battery charging process by determining, based on the temperature, the voltage setpoint to be less than a maximum battery voltage.