Power source with temperature sensing

• US 8,324,868 B2
• Filed: 08/21/2008
• Issued: 12/04/2012
• Est. Priority Date: 08/24/2007
• Status: Expired due to Fees

• Current Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Original Assignee: Valence Technology Incorporated (Lithium Werks B.V.)
• Inventors: Choi, Alexander, Chan, Sunny, Kin, Kwun
• Primary Examiner(s): Assouad, Patrick
• Assistant Examiner(s): Chung, Steve T
• Application Number:
  US12/196,192
• Publication Number:
  US 20090206798A1
• Time in Patent Office: 1,566 Days
• Field of Search: 320/126, 320/150, 320/154, 320/160, 320/120, 320/121, 320/122, 429/61, 429/62, 340/693.2, 307/64, 307/66
• US Class Current: 320/150
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/405 Housings
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A modular and scalable power source can be used to supplement and/or replace existing sources of power. In some embodiments, a DC source can be used to charge a battery in a host system, provide power as a back-up system, or be a primary source of power. The power source includes a set of battery units and one or more circuits that provide an alternative signal path around the battery units if the battery units are at a particular charge level. Temperature sensors are used to turn off or otherwise adjust the alternative signal paths if the temperatures of the alternative signal paths become too high.

Claims

1. An apparatus for managing a battery, comprising:

a voltage sensor connected to a first battery unit to sense a voltage of said first battery unit;

an alternative signal path around said first battery unit to a second battery unit that is connected to said first battery unit in series, said voltage sensor adjusts said alternative path around said first battery unit by enabling said alternative signal path to provide a conduction path to said second battery unit connected to said first battery unit when said voltage sensor senses that said voltage of said first battery unit is above a target level;

a temperature sensor positioned to sense a temperature data indicative of temperature of said alternative signal path; and

a comparator circuit in communication with said temperature sensor and said alternative signal path, said comparator circuit compares an output of said temperature sensor to a reference and adjusts said alternative signal path based on said comparison, said comparator circuit turns off said alternative signal path if said temperature data sensed by said temperature sensor indicates that said temperature of said alternative path is greater than or equal to a threshold temperature.

2. An apparatus according to claim 1, wherein:

said alternative signal path is in communication with a source of charging for said first battery unit and with a terminal of said first battery unit.

3. An apparatus according to claim 2, wherein:

said alternative signal path provides a path for a portion of current for said first battery unit from said source of charging;

said alternative signal path provides a current path to said second battery unit; and

said second battery unit is in series with said first battery unit.

4. An apparatus according to claim 1, wherein:

and

said comparator turns off said alternative signal path if said output of said temperature sensor has reached a reference value.

5. An apparatus according to claim 1, wherein:

said first battery unit includes multiple battery cells in parallel, each said battery cell of said first battery unit is associated with a cell path such that when a voltage of a first battery cell is above a target level, said cell path associated with said first battery cell provides a conductive path to a second battery cell connected to said first battery cell.

6. An apparatus according to claim 1, wherein:

said first battery unit includes one battery cell.

7. An apparatus according to claim 1, wherein:

said comparator circuit is connected to a circuit associated with said temperature sensor; and

said comparator circuit is in communication with said temperature sensor via said circuit associated with said temperature sensor.

8. An apparatus according to claim 1, further comprising:

a heat sink, said alternative signal path is connected to a heat sink, said temperature sensor senses a temperature of said heat sink.

9. An apparatus according to claim 8, further comprising:

a circuit board, said alternative signal path is positioned on a first side of a circuit board, said heat sink is positioned on a second side of said circuit board, said circuit board includes vias through said circuit board for conducting heat from said alternative signal path to said heat sink, said temperature sensor is in proximity to said heat sink.

10. An apparatus according to claim 1, wherein:

said alternative signal path includes two transistors in a Darlington configuration.

11. An apparatus for managing a battery, comprising:

a set of connected battery units; and

a set of balancing circuits connected to said battery units, said balancing circuits each comprise;

a voltage sensor connected to a first battery unit;

an alternative signal path in communication with a terminal of said first battery unit and a terminal of a second battery unit connected to said first battery unit, said alternative signal path provides a conductive path to said second battery unit when said voltage sensor senses that a voltage of said first battery unit is above a target voltage;

a temperature sensor positioned to sense temperature data indicative of temperature of said alternative signal path; and

a comparison circuit in communication with said voltage sensor, said temperature sensor and said alternative signal path, said comparison circuit adjusts said alternative signal path to enable said alternative path to thereby provide said conductive path to said second battery unit when said voltage sensor senses that said voltage of said first battery unit is above said target voltage and adjusts said alternative signal path to turn off said alternative signal path if said temperature data indicative of said temperature of said alternative signal path indicates a threshold temperature.

12. An apparatus according to claim 11, wherein:

said set of connected battery units are connected in series;

said set of connected battery units are connectable to a source of charging;

each alternative signal path is in communication with said source of charging; and

each alternative signal path conducts less than all current of said source of charging.

13. An apparatus according to claim 11, wherein:

said comparator circuit is connected to a circuit associated with said temperature sensor; and

said comparator circuit is in communication with said temperature sensor via said circuit associated with said temperature sensor; and

each of said set of connected battery units includes multiple battery cells connected in parallel, each said battery cell is associated with a cell path such that a cell path associated with a first battery cell provides a conductive path to a second battery cell connected to said first battery cell when a voltage of said first battery cell is above a target level.

14. An apparatus according to claim 11, wherein said balancing circuits further comprise:

a heat sink, said alternative signal path is connected to said heat sink, said temperature sensor senses temperature of said heat sink; and

a circuit board, said alternative signal path is positioned on a first side of said circuit board, said heat sink is positioned on a second side of said circuit board, said circuit board includes vias through said circuit board for conducting heat from said alternative signal path to said heat sink.

15. A method for managing a battery, comprising:

monitoring voltages of a set of connected battery units;

providing one or more alternative signal paths around a first battery unit that reaches one or more target voltage levels, said providing one or more alternative signal paths around said first battery unit that reaches one or more target voltage levels includes providing a conduction path to a second battery unit connected to said first battery unit when the first battery unit reaches the one or more target voltage levels;

monitoring temperatures of said alternative signal paths;

if the first battery unit reaches the one or more target voltage levels, determining whether said temperatures of said alternative paths are less than one or more threshold temperatures; and

adjusting alternative signal paths that have reached one or more threshold temperatures responsive to said determination, said adjusting said alternative signal path includes turning off said alternative signal paths if said temperatures of said alternative paths have reached a predetermined temperature.

16. A method according to claim 15, wherein:

each of said set of connected battery units includes multiple battery cells connected in parallel, said providing one or more alternative paths around said first battery unit includes providing one or more cell paths around a first battery cell that reaches one or more target voltage levels, said providing one or more cell paths around said first battery cell includes providing a conduction path to a second battery cell connected to said first battery cell.

17. A method according to claim 15, wherein:

said battery units are connected in series;

providing one or more alternative signal paths around said first battery unit includes providing a conduction path to a next battery unit connected in series.

18. A method according to claim 15, further comprising:

charging said battery units, said monitoring voltages and said providing one or more alternative signal paths are performed while charging said battery units, said monitoring temperatures and said adjusting alternative signal paths are also performed while charging said battery units.

19. A method for managing a battery, comprising:

monitoring a voltage of a first battery unit while said first battery unit receives a charging signal;

if said voltage reaches a target level, adjusting an alternative path around said first battery unit to cause more of said charging signal to use said alternative path, said alternative path around said first battery unit provides a conductive path for said charging signal to a second battery unit connected to said first battery unit when said voltage of said first battery unit reaches the target level;

monitoring temperature for said alternative path;

determining if said temperature for said alternative path is less than a threshold level when the first battery unit reaches the target level; and

if said temperature for said alternative path reaches said threshold level, adjusting said alternative path to cause less of said charging signal to use said alternative path.

20. A method according to claim 19, wherein:

said adjusting an alternative path around said first battery unit for said charging signal to cause more of said charging signal to use said alternative path includes turning on said alternative path so that said alternative path provides a current path for said charging signal.

21. A method according to claim 19, wherein:

said adjusting said alternative path to cause less of said charging signal to use said alternative path includes turning off said alternative path so that said alternative path does not conduct current.

22. A method according to claim 19, wherein:

said alternative path conducts only a portion of current of said charging signal; and

said first battery unit includes multiple battery cells connected in parallel, each said battery cell of said first battery unit is associated with a cell path such that when a voltage of a first battery cell is above a target level, said cell path associated with said first battery cell provides a current path to a second battery cell connected to said first battery cell.