Energy storage system for electric or hybrid vehicle

• US 20070159007A1
• Filed: 01/09/2006
• Published: 07/12/2007
• Est. Priority Date: 01/09/2006
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Salasoo, Lembit, King, Robert, Richter, Timothy
• Granted Patent: US 7,489,048 B2
• Time in Patent Office: Days
• US Class Current: 307/71
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• 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 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A battery load leveling system for an electrically powered system in which a battery is subject to intermittent high current loading, the system including a first battery, a second battery, and a load coupled to the batteries. The system includes a passive storage device, a unidirectional conducting apparatus coupled in series electrical circuit with the passive storage device and poled to conduct current from the passive storage device to the load, the series electrical circuit coupled in parallel with the battery such that the passive storage device provides current to the load when the battery terminal voltage is less than voltage on the passive storage device, and a battery switching circuit that connects the first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.

Claims

1. A battery load leveling system for an electrically powered system in which a battery is subject to intermittent high current loading, the system including a first battery, a second battery, and a load coupled to the first and second batteries, said system comprising:

a passive storage device;

a unidirectional conducting apparatus coupled in series electrical circuit with said passive storage device and poled to conduct current from said passive storage device to the load, said series electrical circuit coupled in parallel with the batteries such that said passive storage device provides current to the load when the battery terminal voltage is less than voltage on said passive storage device; and

a battery switching circuit that connects the first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.

2. A battery load leveling system in accordance with claim 1 further comprising an electrical disconnect configured to disconnect said battery switching circuit from said passive storage device.

3. A battery load leveling system in accordance with claim 2 further comprising a controller to selectively operate said electrical disconnect based on the voltage of said passive storage device and direction and magnitude of power flow from the load.

4. A battery load leveling system in accordance with claim 1 wherein said battery switching circuit comprises a first contactor, a second contactor, and a third contactor, said first and second contactors operable to connect the first and second batteries in a lower voltage parallel arrangement, and said third contactor is operable to connect the first and second batteries in a higher voltage series arrangement.

5. A battery load leveling system in accordance with claim 4 further comprising:

a fourth contactor that is coupled in series with said first contactor;

a first apparatus for approximately simultaneously actuating said first and fourth contactors; and

a second apparatus for approximately simultaneously actuating said second and third contactor.

6. A battery load leveling system in accordance with claim 5 wherein said second apparatus comprises a mechanical interlock that is coupled between said first and fourth contactors and said second and third contactors, said mechanical interlock configured to open said first and fourth contactors and approximately simultaneously close said second and third contactors to facilitate preventing a short circuit.

7. A battery load leveling system in accordance with claim 5 further comprising a mechanical interlock configured to prevent switching said first and second batteries from a parallel arrangement to a series arrangement in the event of a fault including welded contacts.

8. A battery load leveling system in accordance with claim 1 further comprising a first diode coupled in series with said first battery and a second diode coupled in series with said second battery such that when power flows from said first and second batteries to the load, said first and second batteries are arranged in the lower voltage parallel mode.

9. A battery load leveling system in accordance with claim 8 further comprising an electrical disconnect that electrically connects said first and second batteries in a higher voltage series mode for either direction of power flow or current flow from the load.

10. A battery load leveling system in accordance with claim 9 wherein said electrical disconnect is implemented using back-to-back silicon controlled rectifiers.

11. A battery load leveling system in accordance with claim 9 wherein said electrical disconnect is implemented using a solid state switch.

12. A battery load leveling system in accordance with claim 1 wherein said first and second batteries comprise at least one of a sodium nickel chloride battery and a sodium sulfur battery that are each operable at a temperature that is greater than 260 degrees Celsius.

13. A battery load leveling system in accordance with claim 12 further comprising at least one electrical disconnect coupled in series with one or both terminals of each of said first and second batteries to allow galvanic isolation and to prevent leakage current flowing through said first and second batteries when in a cold or frozen state.

14. A battery load leveling system in accordance with claim 1 further comprising a controller coupled to said battery switching circuit, said controller configured to connect said first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement based on at least one of a motor speed, a torque command, a passive storage device voltage, and a battery unit voltage.

15. A battery load leveling system in accordance with claim 1 further comprising a pre-charge circuit configured to charge said passive storage device using an external power source.

16. A battery load leveling system in accordance with claim 15 wherein said external power source comprises a hybrid vehicle engine that charges said passive storage device through an electrical circuit with the drive configured to accept regenerative power from the load.

17. A battery load leveling system in accordance with claim 15 wherein said pre-charge circuit is configured to accept regenerative power from the load using a semiconductor switch.

18. A:

battery load leveling system in accordance with claim 15 wherein said external power source comprises said first and second batteries, said battery switching circuit configured to couple said first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.

19. A battery load leveling system in accordance with claim 17 wherein said semiconductor switch comprises at least one of a silicon-controlled rectifier, a bipolar transistor, a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) and a Gate Turnoff Thyristor (GTO).

20. A battery load leveling system in accordance with claim 1 wherein said first and second batteries comprise at least one of a sodium nickel chloride battery, a sodium sulfur battery, a fuel cell, a nickel metal hydride battery, a lithium ion battery, a lithium polymer battery, a nickel cadmium battery, and a lead acid battery.

21. A battery load leveling system in accordance with claim 1 wherein said unidirectional conducting apparatus comprises a diode.

22. An electric vehicle comprising:

a first battery;

a second battery;

a load coupled to said first and second batteries;

said first and second batteries configured to provide the propulsive force for moving the vehicle; and

a battery load leveling system including

a passive storage device;

a unidirectional conducting apparatus coupled in series electrical circuit with said passive storage device and poled to conduct current from said passive storage device to the load, said series electrical circuit coupled in parallel with at least one of said first and second batteries such that said passive storage device provides current to the load when the battery terminal voltage of at least one of said first and second batteries is less than voltage on said passive storage device; and

a battery switching circuit that connects said first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.

23. A hybrid vehicle comprising:

a first battery;

a second battery;

a load coupled to said first and second batteries; and

a battery load leveling system including

a passive storage device;

a unidirectional conducting apparatus coupled in a series electrical circuit with said passive storage device and poled to conduct current from said passive storage device to the load, said series electrical circuit coupled in parallel with at least one of said first and second batteries such that said passive storage device provides current to the load when the battery terminal voltage of at least one of said first and second batteries is less than the voltage on said passive storage device; and

a battery switching circuit that connects said first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.

24. A method of assembling a battery load leveling system for an electrically powered system in which a battery is subject to intermittent high current loading, the system including a first battery, a second battery, and a load coupled to the first and second batteries, said method comprising:

coupling a unidirectional conducting apparatus in a series electrical circuit with a passive storage device such that the unidirectional conducting apparatus is poled to conduct current from the passive storage device to a load;

coupling the series electrical circuit in parallel with the first and second batteries such that said passive storage device provides current to the load when the battery terminal voltage is less than voltage on the passive storage device; and

utilizing a battery switching circuit to the first and second batteries in either a lower voltage parallel arrangement or a higher voltage series arrangement.

25. A method in accordance with claim 24 further comprising coupling an electrical disconnect between the battery switching circuit and the passive storage device.

26. A method in accordance with claim 25 further comprising coupling a controller to the electrical disconnect, the controller configured to selectively operate the electrical disconnect based on the voltage of the passive storage device and direction and magnitude of power flow from the load.

27. A method in accordance with claim 24 wherein the battery switching circuit includes a first contactor, a second contactor, and a third contactor, said method further comprising coupling the first and second contactors to the first and second batteries such that the first and second contactors facilitate coupling the first and second batteries in a lower voltage parallel arrangement, and such that the third contactor facilitates coupling the first and second batteries in a higher voltage series arrangement.