Dual Function Battery System and Method

• US 20140183939A1
• Filed: 08/29/2013
• Published: 07/03/2014
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: CPS Technology Holdings, LLC
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Jiang, Junwei, Wyatt, Perry M., Watson, Thomas M., Hurley, Patrick T.
• Granted Patent: US 10,106,038 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60L 1/08 Methods and devices for control or regulation
• 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 2260/26 Transition between different drive modes
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 7/10 Dynamic electric regenerative braking B60L7/22 takes precedence
• 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 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4278 Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An energy storage system for supporting dual electrical functions of a vehicle includes an energy storage unit having a plurality of energy storage modules connected in series, a plurality of sensing units for sensing state of charges of the plurality of energy storage modules, and a pair of primary voltage terminals. The series connected plurality of energy storage modules is connectable across the pair of primary voltage terminals during a key-on state of the vehicle to supply energy storage power at a first voltage level to support primary electrical functions of the vehicle. The energy storage system is further configured to select a subset of the plurality of energy storage modules during a key-off state of the vehicle to connect across a pair of secondary voltage terminals using a switch network to supply energy storage power at a second voltage level.

Claims

1. An energy storage system for a vehicle, comprising:

an energy storage unit having a plurality of energy storage modules connected in series;

a plurality of sensing units coupled to the plurality of energy storage modules, wherein each of the plurality of sensing units is configured to sense a state of a respective energy storage module, and wherein the sensed state enables an estimation of the state of charge of the respective energy storage module;

a pair of primary voltage terminals, wherein the series connected plurality of energy storage modules is connectable across the pair of primary voltage terminals to supply energy storage power at a first voltage level to support primary electrical functions of the vehicle;

a pair of secondary voltage terminals; and

a controller configured to select a first subset of the plurality of energy storage modules to connect across the pair of secondary voltage terminals to supply energy storage power at a second voltage level, which is lower that the first voltage level, wherein based on estimated state of charges the controller determines whether the first subset of the plurality of energy storage modules should be disconnected from the pair of secondary voltage terminals and a second subset of the plurality of energy storage modules connected across the pair of secondary voltage terminals to continue supplying energy storage power at the second voltage level.

2. The energy storage system of claim 1, wherein:

each of the plurality of energy storage modules has a positive pole and a negative pole;

the pair of secondary voltage terminals includes a positive terminal and a negative terminal;

the controller controls a switching network that includes a first plurality of switches respectively, individually connected between the positive poles of the plurality of energy storage modules and the positive terminal of the secondary voltage terminals, and a second plurality of switches respectively, individually connected between the negative poles of the plurality of energy storage modules and the negative terminal of the secondary voltage terminals; and

an activation unit for selectively turning on associated pairs of the switches respectively connected to the positive and negative poles of the battery modules.

3. The energy storage system of claim 1, wherein each of the plurality of energy storage modules has one or more cells connected in series or parallel.

4. The energy storage system of claim 1, further comprising a key-off detector configured to detect when the key of a vehicle has been turned to a key-off position, and wherein in response to the key-off detection the controller selectively connects one of the plurality of energy storage modules across the pair of low voltage battery terminals to provide power to a key-off accessory of the vehicle.

5. The energy storage system of claim 1, wherein each of the plurality of sensing units is coupled to one of the plurality of energy storage modules, wherein the controller is configured to compare the estimated state of charges of the plurality of energy storage modules to respective preselected minimum state of charges, and wherein when the state of charge of one of the first subset energy storage modules that is connected across the secondary voltage terminals decreases to the respective preselected minimum state of charge the controller automatically disconnect the one energy storage module from the low voltage terminal and connect one of the second subset of plurality of energy storage modules.

6. The energy storage system of claim 1, wherein each of the plurality of energy storage modules has at least one of an equal number of energy storage cells that all produce power at approximately the same voltage, a plurality of energy storage cells connected in series, a plurality of cells connected in parallel, at least one energy storage cell with chemistry of one of (a) NCA, (b) NMC, (c) LiMn2O4, and (d) a blend of the chemistries of (a), (b), and (c), cells with cathode material having cell chemistry that is olivine based material, cells with cathode material made of LiFe1-xPO4 in which x is greater or equal to zero and less than or equal to one, and cells with cathode material that is made of olivine material Zx doped LiFePO4, in which x is greater or equal to zero and less than or equal to one.

7. The energy storage system of claim 1, wherein at least one of the plurality of battery modules has a different number of energy storage cells than that of one of the remaining energy modules.

8. A computer-implemented method for performing dual functions of an energy storage system in a vehicle, comprising:

providing stored electrical power for supporting primary electrical functions of the vehicle during a key-on state at a pair of primary voltage terminals of the energy storage system having a plurality of energy storage modules connected in series across the pair of primary voltage terminals;

detecting when the vehicle has been turned off; and

providing stored electrical power from a reduced number of the plurality of energy storage modules for supporting secondary electrical functions of the vehicle, thereby operating key-off loads of the vehicle at a pair of secondary terminals by connecting the reduced number of the plurality of energy storage modules across the pair of secondary terminals.

9. The computer-implemented method of claim 8, further comprising:

controlling a switching network to successively, individually connect the plurality of energy storage modules across the pair of secondary voltage terminals.

10. The computer-implemented method of claim 8, further comprising:

estimating a state of charge of one of the reduced number of the plurality of energy storage modules connected across the pair of secondary voltage terminals; and

in response to the estimated state of charge determining whether the one energy storage module should be disconnected from the pair of secondary voltage terminals and one of the remaining energy storage modules not associated with the reduced number of energy storage modules should be connected across the pair of secondary voltage terminals.

11. The computer-implemented method of claim 10, wherein estimating the state of charge further comprises:

disconnecting the one of the energy storage modules from the secondary voltage terminals if a difference between the estimated state of charge and a preselected state of charge level is less than a predetermined value;

estimating a state of charge of the one of the remaining energy storage modules; and

connecting the one of the remaining energy storage modules to the secondary energy storage terminals if a difference between the estimated state of charge of the one of the remaining energy storage modules and the preselected state of charge level is greater than the predetermined value.

12. The computer-implemented method of claim 11, further comprising:

establishing a preselected order of succession in which the battery modules are successively connected across the pair of secondary voltage terminals.

13. The computer-implemented method of claim 12, further comprising:

detecting a key-off state of the vehicle using a key-off detector;

determining which one of the key-off loads requires a supply of power while the vehicle is not operating; and

selecting one of the plurality of battery modules for connection across the pair of secondary battery terminals to provide stored energy power to the determined key-off load.

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

providing stored energy from the pair of secondary terminals to a vehicle accessory load that requires power when the vehicle is being operated.

15. The computer-implemented method of claim 8, wherein each of the plurality of energy storage modules has one or more electrochemical or electrostatic cells connected in series or parallel.

16. The computer-implemented method of claim 9, wherein the switching network includes a first plurality of switches respectively, individually connected between the positive poles of the plurality of energy storage modules and the positive terminal of the secondary voltage terminals, and a second plurality of switches respectively, individually connected between the negative poles of the plurality of energy storage modules and the negative terminal of the secondary voltage terminals.

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

an activation unit for selectively turning on or off associated pairs of the switches respectively connected to the positive and negative poles of the battery modules.

18. A computing system, comprising:

at least one processing unit and at least one memory unit storing instructions that are operable, when executed by the at least one processing unit, to cause the at least one processing unit to perform a method for performing dual functions of an energy storage system in a vehicle, the method comprising;

providing stored electrical power for supporting primary electrical functions of the vehicle during a key-on state at a pair of primary voltage terminals of the energy storage system having a plurality of energy storage modules connected in series across the pair of primary voltage terminals;

detecting when the vehicle has been turned off; and

providing stored electrical power from a reduced number of the plurality of energy storage modules for supporting secondary electrical functions of the vehicle, thereby operating key-off loads of the vehicle at a pair of secondary terminals by connecting the reduced number of the plurality of energy storage modules across the pair of secondary terminals.

19. The computing system of claim 18, further comprising:

controlling a switching network to successively, individually connect the plurality of energy storage modules across the pair of secondary voltage terminals.

20. The computing system of claim 18, further comprising:

estimating a state of charge of one of the reduced number of the plurality of energy storage modules connected across the pair of secondary voltage terminals; and

in response to the estimated state of charge determining whether the one energy storage module should be disconnected from the pair of secondary voltage terminals and one of the remaining energy storage modules not associated with the reduced number of energy storage modules should be connected across the pair of secondary voltage terminals.