Techniques for adjusting wakeup time of an electrified vehicle for low voltage battery conditioning

Patent metadata

Field	Value
Publication number	US-10543757-B2
Application number	US-201715837534-A
Country	US
Kind code	B2
Filing date	Dec 11, 2017
Priority date	Dec 11, 2017
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

A control system for an electrified vehicle having low and high voltage battery systems includes a set of vehicle modules that collectively draw an ignition-off draw (IOD) current from the low voltage battery system while the vehicle is off, a set of sensors configured to measure a set of parameters of at least one of the low and high voltage battery systems, and a controller configured to: estimate the IOD current, receive the set of measured parameters from the set of sensors, based on the set of measured parameters and the estimated IOD current, set a wakeup time indicative of a future time at which the low voltage battery system will require recharging, and based on the wakeup time, temporarily wakeup the vehicle such that recharging of the low voltage battery system using the high voltage battery system is enabled.

First claim

What is claimed is:

1. A control system for an electrified vehicle having low and high voltage battery systems, the control system comprising:
a set of vehicle modules that collectively draw an ignition-off draw (IOD) current from the low voltage battery system while the vehicle is off;
a set of sensors configured to measure a set of parameters of at least one of the low and high voltage battery systems; and
a controller configured to:
in response to detecting a vehicle on-off transition is occurring:
estimate the IOD current;
receive the set of measured parameters from the set of sensors; and
based on the set of measured parameters and the estimated IOD current, determine a wakeup time indicative of a future time at which the low voltage battery system will require recharging;

after determining the wakeup time, initiate a wakeup timer based on the wakeup time;
after initiating the wakeup timer, turn off the vehicle to complete the vehicle on-off transition;
in response to the wakeup timer expiring, temporarily wakeup the vehicle; and
upon temporarily waking up the vehicle, control the high voltage battery system to recharge the low voltage battery system.

2. The control system of claim 1 , wherein the controller is configured to initially perform a conservative estimate of the IOD current based on which of the set of vehicle modules are active.

3. The control system of claim 2 , wherein upon temporarily waking up the vehicle, the controller is further configured to relearn the wakeup time by:
determining a current state of charge (SOC) of the low voltage battery system;
based on the estimated IOD current, determining an expected SOC of the low voltage battery system; and
adjusting the estimated IOD current based on a difference between the current and expected SOC of the low voltage battery system thereby providing for continuing relearning of the wakeup time.

4. The control system of claim 1 , wherein the set of parameters includes at least one of a capacity of the low voltage battery system, ambient temperature, a state of charge of the low and high voltage battery systems before the vehicle was turned off, and a time of day.

5. The control system of claim 1 , further comprising a main contactor disposed between a direct current to direct current (DC-DC) converter and the high voltage battery system, the DC-DC converter also being connected to the low voltage battery system,
wherein the controller is configured to open the main contactor while the vehicle is off and close the main contactor while the vehicle is temporarily woken up such that the DC-DC converter steps down a voltage of the high voltage battery system for recharging of the low voltage battery system.

6. The control system of claim 1 , wherein the vehicle is a plug-in hybrid electric vehicle (PHEV) that is configured to recharge the high voltage battery system via wall power, and wherein the set of parameters includes a current state of charge (SOC) of the high voltage battery system.

7. The control system of claim 1 , wherein the set of vehicle modules includes at least one of a body controller module, an on-board charger module, a power inverter module, a battery pack control module, and an intelligent battery sensor.

8. The control system of claim 1 , wherein the set of vehicle modules includes any vehicle modules actively communicating on a controller area network (CAN).

9. A method for controlling recharging of a low voltage battery system of an electrified vehicle that also includes a high voltage battery system, the method comprising:
operating a set of vehicle modules that collectively draw an ignition-off draw (IOD) current from the low voltage battery system while the vehicle is off;
receiving, by a control system of the vehicle and from a set of sensors, a set of measured parameters of at least one of the low and high voltage battery systems;
in response to detecting a vehicle on-off transition is occurring:
estimating, by the control system, the IOD current; and
based on the set of measured parameters and the estimated IOD current, determining, by the control system a wakeup time indicative of a future time at which the low voltage battery system will require recharging;

after determining the wakeup time, initiating, by the control system, a wakeup timer based on the wakeup time;
after initiating the wakeup timer, turning off, by the control system, to complete the vehicle on-off transition;
in response to the wakeup timer expiring, temporarily waking up, by the control system, the vehicle; and
while the vehicle is temporarily awake, controlling, by the control system, the high voltage battery system to recharge the low voltage battery system.

10. The method of claim 9 , further comprising initially performing, by the control system, a conservative estimate of the IOD current based on which of the set of vehicle modules are active.

11. The method of claim 10 , wherein the method further comprises upon temporarily waking up the vehicle, relearning the wakeup time by:
determining, by the control system, a current state of charge (SOC) of the low voltage battery system;
based on the estimate IOD current, determining, by the control system, an expected SOC of the low voltage battery system; and
adjusting, by the control system, the estimated IOD current based on a difference between the current and expected SOC of the low voltage battery system thereby providing for continuing relearning of the wakeup time.

12. The method of claim 9 , wherein the set of parameters includes at least one of a capacity of the low voltage battery system, ambient temperature, a state of charge of the low and high voltage battery systems before the vehicle was turned off, and a time of day.

13. The method of claim 9 , wherein a main contactor is disposed between a direct current to direct current (DC-DC) converter and the high voltage battery system, the DC-DC converter also being connected to the low voltage battery system, and further comprising:
opening, by the control system, the main contactor while the vehicle is off; and
closing, by the control system, the main contactor while the vehicle is temporarily woken up such that the DC-DC converter steps down a voltage of the high voltage battery system for recharging of the low voltage battery system.

14. The method of claim 9 , wherein the vehicle is a plug-in hybrid electric vehicle (PHEV) that is configured to recharge the high voltage battery system via wall power, and wherein the set of parameters includes a current state of charge (SOC) of the high voltage battery system.

15. The method of claim 9 , wherein the set of vehicle modules includes at least one of a body controller module, an on-board charger module, a power inverter module, a battery pack control module, and an intelligent battery sensor.

16. The method of claim 9 , wherein the set of vehicle modules includes any vehicle modules actively communicating on a controller area network (CAN).

17. A control system for an electrified vehicle having low and high voltage battery systems, the control system comprising:
a set of vehicle modules that collectively draw an ignition-off draw (IOD) current from the low voltage battery system while the vehicle is off;
a set of sensors configured to measure a set of parameters of at least one of the low and high voltage battery systems; and
a controller configured to;
estimate the IOD current, including initially performing a conservative estimate of the IOD current based on which of the set of vehicle modules are active;
receive t

Assignees

• Diab Moustapha
• Weslati Feisel
• Fca Us Llc

Inventors

• Diab Moustapha
• Weslati Feisel

Classifications

• B60L2240/547

  Voltage · CPC title

• B60L2240/80

  Time limits · CPC title

• B60L58/14

  Preventing excessive discharging · CPC title

• Y10S903/907

  Electricity storage, e.g. battery, capacitor · CPC title

• B60L58/20

  having different nominal voltages · CPC title