Self-discharge for high voltage battery packs

• US 9,614,383 B2
• Filed: 03/04/2013
• Issued: 04/04/2017
• Est. Priority Date: 05/19/2012
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Boggs, Brian Stuart, Darragh, Joseph Michael, Paryani, Anil, Chou, Chuen
• Primary Examiner(s): PELTON, NATHANIEL R
• Application Number:
  US13/784,542
• Publication Number:
  US 20130307480A1
• Time in Patent Office: 1,492 Days
• Field of Search: 320118, 320127, 320135, 320136
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 53/16 Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/60 Monitoring or controlling charging stations
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/26 by cooling
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A system and method for providing energy management and maintenance of a high energy battery pack through use self-discharge features and processes. A battery pack is configured with self-discharger enabled-components that selectively discharge energy from the battery pack without the battery pack providing operational power.

Claims

1. A self-dischargeable rechargeable high-voltage battery pack, comprising:

a plurality of series-coupled energy storage elements;

a housing enclosing and sealing said plurality of series-coupled energy storage elements with a plurality of exterior walls;

an operational port coupled to a portion of a first particular one exterior wall of said plurality of exterior walls, said operational port providing an energy transfer with respect to said plurality of series-coupled energy storage elements;

a self-discharger, responsive to a self-discharge signal, initiating an internal dissipation of energy at an intentional self-discharge rate of at least 5 W from said plurality of series-coupled energy storage elements while said self-discharge signal is asserted without said energy transfer through said operational port, wherein said internal dissipation of energy is disabled when said self-discharge signal is not asserted; and

a battery precharger mechanism coupled to said plurality of series-coupled energy storage elements selectively limiting a current flow from said plurality of series-coupled energy storage elements in a first mode wherein said self-discharger includes said battery precharger mechanism in a second mode that constantly dissipates energy from all said series-coupled energy storage elements at once.

2. The self-dischargeable rechargeable high-voltage battery pack of claim 1 further comprising a motion sensor detecting an acceleration profile associated with a collision event wherein said self-discharge signal is asserted automatically in response to said collision event.

3. The self-dischargeable rechargeable high-voltage battery pack of claim 1 further comprising a battery management system disposed within said housing and coupled to said self-discharger, said battery management system asserting said self-discharge signal until a discharge endpoint is reached wherein said battery management system stops asserting said self-discharge signal.

4. The self-dischargeable rechargeable high-voltage battery pack of claim 2 further comprising a battery management system disposed within said housing and coupled to said self-discharger and to said motion sensor, said battery management system asserting said self-discharge signal in response to said collision event until a discharge endpoint is reached wherein said battery management system stops asserting said self-discharge signal.

5. The self-dischargeable rechargeable high-voltage battery pack of claim 1 further comprising a battery balancing mechanism coupled to said plurality of series-coupled energy storage elements selectively individually balancing a voltage of said plurality of series-coupled energy storage elements in a third mode wherein said self-discharger includes said battery balancing mechanism in said second mode that constantly dissipates energy from all said series-coupled energy storage elements at once.

6. The self-dischargeable rechargeable high-voltage battery pack of claim 1 further comprising an operating environment including an electric motor coupled to said operational port, said electric motor operable by said energy transfer from said plurality of series-coupled energy storage elements.

7. The self-dischargeable rechargeable high-voltage battery pack of claim 6 wherein said operational port includes a power connector and a communications interface and wherein said operating environment provides said self-discharge signal through said communications interface.

8. The self-dischargeable rechargeable high-voltage battery pack of claim 1 wherein said internal dissipation of energy from the plurality of series-coupled energy storage elements occurs at a self-discharge rate of 5-50 W.

9. The self-dischargeable rechargeable high-voltage battery pack of claim 1 further comprising a processing system coupled to said pluralities of series-coupled energy storage elements, said processing system including a power conserving operating mode reducing an internal power dissipation of said pluralities of series-coupled energy storage elements wherein said self-discharger selectively actuates, in response to said self-discharge signal, a power consuming operating mode for said pluralities of series-coupled energy storage elements that disables said power conserving operating mode and wherein said self-discharger enables said power conserving operating mode when said self-discharge signal is not enabled.

10. The self-dischargeable rechargeable high-voltage battery pack of claim 1 wherein said operational port includes a power connector and a communications interface and further comprising a service unit separate from a battery management system, the service unit coupled to said operational port and asserting said self-discharge signal through said communications interface.

11. A self-dischargeable rechargeable high-voltage battery pack, comprising:

a plurality of battery modules serially coupled to each other;

inside each of the plurality of battery modules, a plurality of series-coupled energy storage elements;

a housing enclosing and sealing said plurality of battery modules with a plurality of exterior walls;

an operational port coupled to a portion of a first particular one exterior wall of said plurality of exterior walls, said operational port providing an energy transfer with respect to said pluralities of series-coupled energy storage elements;

a self-discharger, responsive to a self-discharge signal, initiating an internal dissipation of energy at an intentional self-discharge rate of at least 5 W from said pluralities of series-coupled energy storage elements while said self-discharge signal is asserted without said energy transfer through said operational port, wherein said internal dissipation of energy is disabled when said self-discharge signal is not asserted; and

a plurality of energy dissipative elements selectively functionally coupled to said pluralities of series-coupled energy storage elements, wherein each of the plurality of energy dissipative elements is installed at a respective one of the plurality of battery modules, wherein said self-discharger selectively enables said energy dissipative elements to dissipate energy from said pluralities of series-coupled energy storage elements in response to said assertion of said self-discharge signal, said plurality of energy dissipative elements not dissipating energy from said plurality of series-coupled energy storage elements when said self-discharge signal is not asserted.

12. The self-dischargeable rechargeable high-voltage battery pack of claim 11 further comprising a processing system coupled to said pluralities of series-coupled energy storage elements, said processing system including a power conserving operating mode reducing an internal power dissipation of said pluralities of series-coupled energy storage elements wherein said self-discharger selectively actuates, in response to said self-discharge signal, a power consuming operating mode for said pluralities of series-coupled energy storage elements that disables said power conserving operating mode and wherein said self-discharger enables said power conserving operating mode when said self-discharge signal is not enabled.

13. The self-dischargeable rechargeable high-voltage battery pack of claim 11, wherein said operational port includes a power connector and a communications interface and further comprising a service unit separate from a battery management system, the service unit coupled to said operational port and asserting said self-discharge signal through said communications interface.

16. The computer-implemented method of claim 13 further comprising:

c) terminating automatically said self-discharging when a discharge endpoint is reached.

14. A computer-implemented method for managing a self-dischargeable rechargeable high-voltage battery pack, comprising:

a) configuring the self-dischargeable rechargeable high-voltage battery pack for an energy transfer between the self-dischargeable rechargeable high-voltage battery pack and an exterior operational port, the self-dischargeable rechargeable high-voltage battery pack including a plurality of battery modules serially coupled to each other, and, inside each of the plurality of battery modules, a plurality of series-coupled energy storage elements; and

b) self-discharging the self-dischargeable rechargeable high-voltage battery pack at an intentional self-discharge rate of at least 5 W using a processor in response to an assertion of a self-discharge signal, and using a plurality of energy dissipative elements selectively functionally coupled to said pluralities of series-coupled energy storage elements, wherein each of the plurality of energy dissipative elements is installed at a respective one of the plurality of battery modules, the self-dischargeable rechargeable high-voltage battery pack not self-discharging absent said assertion and not self-discharging using said energy transfer.

15. The computer-implemented method of claim 14 wherein said self-discharging step discharges at a self-discharge rate of 5-50 W.

17. The computer-implemented method of claim 14 wherein said exterior operational port includes a power connector and a communications interface, the method further comprising:

c) asserting said self-discharge signal through said communications interface.

18. The computer-implemented method of claim 14 further comprising:

c) detecting a collision event using a motion detector; and

thereafter

d) asserting automatically said self-discharge signal.

19. The computer-implemented method of claim 14, wherein the self-dischargeable rechargeable high-voltage battery pack includes a processing system coupled to said pluralities of series-coupled energy storage elements, said processing system including a power conserving operating mode reducing an internal power dissipation of said pluralities of series-coupled energy storage elements, the method further comprising actuating a power consuming operating mode for said pluralities of series-coupled energy storage elements that disables said power conserving operating mode, and enabling said power conserving operating mode when said self-discharge signal is not asserted.

20. The computer-implemented method of claim 14, wherein the self-dischargeable rechargeable high-voltage battery pack includes a power connector and a communications interface, and wherein the self-discharge signal is asserted using a service unit separate from a battery management system, the service unit coupled to said exterior operational port and asserting said self-discharge signal through said communications interface.