Electric vehicle and method of control for active auxiliary battery depletion

• US 8,534,400 B2
• Filed: 02/14/2011
• Issued: 09/17/2013
• Est. Priority Date: 02/14/2011
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Stanek, Joseph, Ochocinski, Christopher Adam
• Primary Examiner(s): Walters, John
• Assistant Examiner(s): TRIGGS, JAMES J
• Application Number:
  US13/026,588
• Publication Number:
  US 20110168462A1
• Time in Patent Office: 946 Days
• Field of Search: 320/103, 320/104, 320/109, 180 651- 65285, 307/10.1, 307/64, 307/66
• US Class Current: 180/65.265
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• 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 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

An electric vehicle includes a traction battery, an auxiliary battery, and a controller. The controller is configured to prevent the traction battery from charging the auxiliary battery while the auxiliary battery has more than a minimum energy. The controller is further configured to, upon the auxiliary battery having the minimum energy, enable the traction battery to charge the auxiliary battery such that the auxiliary battery is maintained at the minimum energy.

Claims

1. A method comprising:

discharging an auxiliary battery of an electric vehicle while the auxiliary battery has more than a minimum energy;

preventing a traction battery of the vehicle from charging the auxiliary battery while the auxiliary battery has more than the minimum energy; and

upon the auxiliary battery having the minimum energy, charging the auxiliary battery with the traction battery to maintain the auxiliary battery at the minimum energy.

2. The method of claim 1 further comprising:

recharging the auxiliary battery and the traction battery via an electric grid.

3. The method of claim 1 wherein:

the discharging, preventing, and charging steps occur while the vehicle is being driven.

4. The method of claim 1 wherein:

preventing the traction battery from charging the auxiliary battery includes electrically disconnecting the traction battery from the auxiliary battery; and

charging the auxiliary battery with the traction battery includes electrically connecting the traction battery to the auxiliary battery.

5. The method of claim 1 further comprising:

discharging the traction battery to propel the vehicle;

wherein discharging the auxiliary battery includes discharging the auxiliary battery to operate a vehicle accessory.

6. The method of claim 1 wherein the auxiliary battery and the traction battery are electrically connected to a converter, wherein:

preventing the traction battery from charging the auxiliary battery includes setting a set-point of the converter to a first value that allows for preventing the traction battery from charging the auxiliary battery;

charging the auxiliary battery with the traction battery includes setting the set-point of the converter to a second value that allows for charging the auxiliary battery with the traction battery to maintain the auxiliary battery at the minimum energy.

7. The method of claim 1 wherein:

the minimum energy of the auxiliary battery is a minimum state of charge (SOC) of the auxiliary battery.

8. The method of claim 1 wherein:

the ability of the auxiliary battery to provide energy to a vehicle accessory is compromised when the auxiliary battery has less than the minimum energy.

9. The method of claim 1 wherein:

charging the auxiliary battery with the traction battery includes charging the auxiliary battery with the traction battery to increase energy of the auxiliary battery more than minimum energy.

10. The method of claim 2 further comprising:

connecting the vehicle to the electrical grid for the auxiliary battery and the traction battery to be recharged with energy from the electrical grid.

11. An electric vehicle comprising:

an electric machine;

a traction battery electrically connected with the electric machine;

an auxiliary battery; and

a controller configured to prevent the traction battery from charging the auxiliary battery while the auxiliary battery has more than a minimum energy;

wherein the controller is further configured to, upon the auxiliary battery having the minimum energy, enable the traction battery to charge the auxiliary battery such that the auxiliary battery is maintained at the minimum energy;

wherein the controller is further configured to prevent the traction battery from charging the auxiliary battery and is further configured to enable the traction battery to charge the auxiliary battery while the electric vehicle is being driven.

12. The electric vehicle of claim 11 wherein:

the traction battery and the auxiliary battery are configured to be recharged via an electric grid while the electric vehicle is connected to the electric grid.

14. The electric vehicle of claim 11 wherein:

the traction battery is configured to supply energy for propulsion of the electric vehicle; and

the auxiliary battery is configured to supply energy for operation of a vehicle accessory.

15. The electric vehicle of claim 11 further comprising:

a converter;

wherein the traction battery is electrically connected to the converter and the auxiliary battery is electrically connected to the converter;

wherein the controller is further configured to set a set-point of the converter to a first value that prevents the traction battery from charging the auxiliary battery;

wherein the controller is further configured to set the set-point of the converter to a second value that enables the traction battery to charge the auxiliary battery such that the auxiliary battery is maintained at the minimum energy.

16. The electric vehicle of claim 15 wherein:

the minimum energy of the auxiliary battery is a minimum state of charge (SOC) of the auxiliary battery.

17. The electric vehicle of claim 11 wherein:

the ability of the auxiliary battery to provide energy to a vehicle accessory is compromised when the auxiliary battery has less than the minimum energy.

18. The electric vehicle of claim 11 wherein:

the controller is further configured to enable the traction battery to charge the auxiliary battery to increase energy of the auxiliary battery more than minimum energy.

19. The electric vehicle of claim 11 wherein:

the controller is further configured to enable the auxiliary battery to discharge while the auxiliary battery has more than a minimum energy.

13. An electric vehicle comprising:

an electric machine;

a traction battery electrically connected with the electric machine;

an auxiliary battery; and

a controller configured to prevent the traction battery from charging the auxiliary battery while the auxiliary battery has more than a minimum energy;

wherein the controller is further configured to, upon the auxiliary battery having the minimum energy, enable the traction battery to charge the auxiliary battery such that the auxiliary battery is maintained at the minimum energy;

wherein the controller is further configured to electrically disconnect the traction battery from the auxiliary battery in order to prevent the traction battery from charging the auxiliary battery;

wherein the controller is further configured to electrically connect the traction battery to the auxiliary battery in order to enable the traction battery to charge the auxiliary battery.