Method for automatic energy discharge of a battery pack via internal battery electronics post crash event

• US 9,327,610 B2
• Filed: 09/12/2012
• Issued: 05/03/2016
• Est. Priority Date: 09/12/2012
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Andres, Peter, Frakes, Ryan M., Kelley, Paul W.
• Primary Examiner(s): Tat, Binh
• Application Number:
  US13/612,354
• Publication Number:
  US 20140070772A1
• Time in Patent Office: 1,329 Days
• Field of Search: 320130-139
• US Class Current: 1/1
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2200/00 Safety devices for primary or secondary batteries
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 50/579 in response to shock
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A system and method for individually discharging battery cells in a high voltage vehicle battery. The system includes a battery controller that monitors and controls the state-of-charge of each of the battery cells and a cell balancing circuit for maintaining the charge of the cells substantially equal. The controller receives a signal from a vehicle crash detector indicating that the vehicle has been in a crash, and in response instructs the cell balancing circuit to discharge all of the battery cells.

Claims

1. A method for discharging a vehicle battery having a plurality of battery cells on a vehicle in response to a vehicle damaging event, said vehicle including a battery controller that controls a state-of-charge (SOC) of each of the battery cells and a separate battery cell balancing circuit for each of the battery cells that is operable to discharge each battery cell separate from the other battery cells to balance the SOC of the battery cells, said method comprising:

detecting that the vehicle damaging event has occurred;

providing an event signal to the battery controller instructing the battery controller that the damaging event has occurred;

turning on each of the cell balancing circuits for all of the battery cells to cause the battery cells to discharge in response to the event signal, where a battery module circuit, in response to a signal from the battery controller, controls discharge of all of the battery cells contained in a battery module on the vehicle, and the battery module circuit includes the cell balancing circuit and a cell voltage monitoring circuit for each battery cell in the battery module; and

controlling the discharge of the battery cells.

2. The method according to claim 1 wherein each of the cell balancing circuits includes a resistor and a switch so that when the switch is closed, the cell voltage discharges through the resistor.

3. The method according to claim 2 wherein the switch is a field effect transistor switch.

4. The method according to claim 1 wherein turning on each of the cell balancing circuits includes providing a discharge signal from the battery controller to the battery module circuit that monitors the SOC of each of the battery Cells.

5. The method according to claim 4 wherein the battery module circuit includes an integrated circuit, said integrated circuit receiving SOC signals from the cell voltage monitoring circuits and controlling the cell balancing circuits.

6. The method according to claim 4 wherein the battery module circuit is powered by the battery cells and controls the discharge of each battery cell independent of the battery controller.

7. The method according to claim 1 wherein controlling the discharge of the battery cells includes completely discharging the battery cells.

8. The method according to claim 1 wherein controlling the discharge of the battery cells includes discharging the battery cells for a predetermined period of time.

9. The method according to claim 8 wherein the predetermined period of time is based on the SOC of the battery cells when the crash signal is received.

10. The method according to claim 1 wherein controlling the discharge of the battery cells includes discharging the battery cells to a safe under-voltage limit that does not damage the battery cells.

11. A method for discharging a vehicle battery having a plurality of battery cells on a vehicle in response to a vehicle damaging event, said method comprising:

providing a vehicle damaging event detector that detects the vehicle damaging event and provides an event signal indicative of the vehicle damaging event;

providing a battery controller that controls the vehicle battery, said battery controller receiving the event signal;

providing a plurality of battery module circuits each being controlled by the battery controller and each controlling a certain number of the plurality of battery cells, each battery module circuit including an integrated circuit receiving commands from the battery controller, a cell voltage monitoring circuit for each of the battery cells for monitoring the voltage of the battery cells, and a cell balancing circuit for each of the battery cells that is operable to discharge the battery cell; and

causing the integrated circuit to turn on the cell balancing circuit for each of the battery cells when the integrated circuit receives a discharge signal from the battery controller in response to the event signal.

12. The method according to claim 11 wherein each of the cell balancing circuits includes a resistor and a switch so that when the switch is closed, the cell voltage discharges through the resistor.

13. The method according to claim 11 wherein causing the integrated circuit to turn on the cell balancing circuit includes completely discharging the battery cells.

14. The method according to claim 12 wherein the switch is a field effect transistor switch.

15. The method according to claim 11 wherein causing the integrated circuit to turn on the cell balancing circuit includes discharging the battery cells for a predetermined period of time.

16. The method according to claim 15 wherein the predetermined period of time is based on the SOC of the battery cells when the crash signal is received.

17. The method according to claim 11 wherein causing the integrated circuit to turn on the cell balancing circuit includes discharging the battery cells to a safe under-voltage limit that does not damage the battery cells.

18. A battery discharge system for discharging a vehicle battery a plurality of battery cells on a vehicle in response to a vehicle damaging event, said system comprising:

a vehicle damaging event detector that detects the vehicle damaging event and provides an event signal indicative of the vehicle damaging event;

a battery controller that controls the vehicle battery and is responsive to the event signal; and

a plurality of battery module circuits each being controlled by the battery controller and each controlling a certain number of the plurality of battery cells, each battery module circuit including an integrated circuit receiving commands from the battery controller, a cell voltage monitoring circuit for each of the battery cells for monitoring the voltage of the battery cells, and a cell balancing circuit for each of the battery cells that is operable to discharge the battery cell, wherein the battery controller provides a discharge signal to the integrated circuit in each of the battery module circuits that causes the integrated circuit to turn on the cell balancing circuit for each of the battery cells to discharge the cell.

19. The system according to claim 18 wherein each of the cell balancing circuits includes a resistor and a switch so that when the switch is closed, the cell voltage discharges through the resistor.

20. The system according to claim 18 wherein the battery module circuit is powered by the battery cells and controls the discharge of each battery cell independent of the battery controller.