Inter-module battery balancing using minimum cell voltages to select battery sub-modules to power loads

• US 10,355,496 B1
• Filed: 07/26/2018
• Issued: 07/16/2019
• Est. Priority Date: 07/26/2018
• Status: Active Grant

• Current Assignee: Wisk Aero LLC (The Boeing Co.)
• Original Assignee: Kitty Hawk Corporation
• Inventors: Furman, Scott, Hom, Lewis Romeo
• Primary Examiner(s): Pelton, Nathaniel R
• Assistant Examiner(s): Hernandez, Manuel
• Application Number:
  US16/046,312
• Time in Patent Office: 355 Days
• Field of Search: 320118
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0032 disconnection of loads if battery is not under charge, e.g. in vehicle if engine is not running
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 50/50 On board measures aiming to increase energy efficiency

Abstract

For each battery sub-module in a plurality of battery sub-modules, a voltage associated with a cell in that battery sub-module is received wherein each battery sub-module in the plurality of battery sub-modules includes a plurality of cells. A battery sub-module is selected based at least in part on the received voltages and a set of one or more loads, which draws power from the selected battery sub-module and is not powered by any other battery sub-module in the plurality of battery sub-modules, is configured so that the set of loads at least temporarily does not draw power from the selected battery sub-module.

Claims

1. A method, comprising:

receiving, for each battery sub-module in a plurality of battery sub-modules, a voltage associated with a cell in that battery sub-module, wherein each battery sub-module in the plurality of battery sub-modules includes a plurality of cells;

selecting a battery sub-module from the plurality of battery sub-modules based at least in part on the received voltages by;

comparing a plurality of minimum cell voltages against a voltage threshold in order to identify any battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold;

selecting one or more maximums from the plurality of minimum cell voltages in order to obtain one or more maximums of the minimum cell voltages; and

selecting said any identified battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold and that do not correspond to one of the maximums of the minimum cell voltages; and

configuring a set of one or more loads, which draws power from the selected battery sub-module and is not powered by any other battery sub-module in the plurality of battery sub-modules, so that the set of one or more loads at least temporarily does not draw power from the selected battery sub-module.

2. The method recited in claim 1, wherein configuring the set of one or more loads includes configuring the set of loads which draws power from the selected battery sub-module to be off.

3. The method recited in claim 1, wherein selecting the battery sub-module includes:

in response to determining that there are no battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold;

selecting one or more maximums from a plurality of maximum cell voltages in order to obtain one or more maximums of the maximum cell voltages; and

selecting those battery sub-modules that do not correspond to one of the maximums of the maximum cell voltages.

4. The method recited in claim 1, further including:

determining an imbalance metric associated with a degree of imbalance between battery sub-modules in the plurality of battery sub-modules;

determining whether the imbalance metric exceeds an imbalance threshold;

in response to determining that the imbalance metric exceeds the imbalance threshold;

performing pre-charging balancing; and

charging the plurality of battery sub-modules; and

in response to determining that the imbalance metric does not exceed the imbalance threshold, charging the plurality of battery sub-modules.

5. The method recited in claim 1, further including:

determining an imbalance metric associated with a degree of imbalance between battery sub-modules in the plurality of battery sub-modules;

determining whether the imbalance metric exceeds an imbalance threshold;

in response to determining that the imbalance metric exceeds the imbalance threshold;

performing pre-charging balancing;

charging the plurality of battery sub-modules; and

performing post-charging balancing; and

in response to determining that the imbalance metric does not exceed the imbalance threshold;

charging the plurality of battery sub-modules; and

performing post-charging balancing.

6. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to;

receive, for each battery sub-module in a plurality of battery sub-modules, a voltage associated with a cell in that battery sub-module, wherein each battery sub-module in the plurality of battery sub-modules includes a plurality of cells;

select a battery sub-module from the plurality of battery sub-modules based at least in part on the received voltages by;

comparing a plurality of minimum cell voltages against a voltage threshold in order to identify any battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold;

selecting one or more maximums from the plurality of minimum cell voltages in order to obtain one or more maximums of the minimum cell voltages; and

selecting said any identified battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold and that do not correspond to one of the maximums of the minimum cell voltages; and

configure a set of one or more loads, which draws power from the selected battery sub-module and is not powered by any other battery sub-module in the plurality of battery sub-modules, so that the set of one or more loads at least temporarily does not draw power from the selected battery sub-module.

7. The system recited in claim 6, wherein configuring the set of one or more loads includes configuring the set of loads which draws power from the selected battery sub-module to be off.

8. The system recited in claim 6, wherein selecting the battery sub-module includes:

in response to determining that there are no battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold;

selecting one or more maximums from a plurality of maximum cell voltages in order to obtain one or more maximums of the maximum cell voltages; and

selecting those battery sub-modules that do not correspond to one of the maximums of the maximum cell voltages.

9. The system recited in claim 6, wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to:

determine an imbalance metric associated with a degree of imbalance between battery sub-modules in the plurality of battery sub-modules;

determine whether the imbalance metric exceeds an imbalance threshold;

in response to determining that the imbalance metric exceeds the imbalance threshold;

performing pre-charging balancing; and

charging the plurality of battery sub-modules; and

in response to determining that the imbalance metric does not exceed the imbalance threshold, charging the plurality of battery sub-modules.

10. The system recited in claim 6, wherein the memory is further configured to provide the processor with instructions which when executed cause the processor to:

determine an imbalance metric associated with a degree of imbalance between battery sub-modules in the plurality of battery sub-modules;

determine whether the imbalance metric exceeds an imbalance threshold;

in response to determining that the imbalance metric exceeds the imbalance threshold;

performing pre-charging balancing;

charging the plurality of battery sub-modules; and

performing post-charging balancing; and

in response to determining that the imbalance metric does not exceed the imbalance threshold;

charging the plurality of battery sub-modules; and

performing post-charging balancing.

11. The system recited in claim 6, further comprising:

the plurality of battery sub-modules and the set of one or more loads.

12. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

receiving, for each battery sub-module in a plurality of battery sub-modules, a voltage associated with a cell in that battery sub-module, wherein each battery sub-module in the plurality of battery sub-modules includes a plurality of cells;

selecting a battery sub-module from the plurality of battery sub-modules based at least in part on the received voltages by;

comparing a plurality of minimum cell voltages against a voltage threshold in order to identify any battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold;

selecting one or more maximums from the plurality of minimum cell voltages in order to obtain one or more maximums of the minimum cell voltages; and

selecting said any identified battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold and that do not correspond to one of the maximums of the minimum cell voltages; and

configuring a set of one or more loads, which draws power from the selected battery sub-module and is not powered by any other battery sub-module in the plurality of battery sub-modules, so that the set of one or more loads at least temporarily does not draw power from the selected battery sub-module.

13. The computer program product recited in claim 12, wherein the computer instructions for configuring the set of one or more loads include computer instructions for configuring the set of loads which draws power from the selected battery sub-module to be off.

14. The computer program product recited in claim 12, further comprising computer instructions for:

determining an imbalance metric associated with a degree of imbalance between battery sub-modules in the plurality of battery sub-modules;

determining whether the imbalance metric exceeds an imbalance threshold;

in response to determining that the imbalance metric exceeds the imbalance threshold;

performing pre-charging balancing; and

charging the plurality of battery sub-modules; and

in response to determining that the imbalance metric does not exceed the imbalance threshold, charging the plurality of battery sub-modules.

15. The computer program product recited in claim 12, further comprising computer instructions for:

determining an imbalance metric associated with a degree of imbalance between battery sub-modules in the plurality of battery sub-modules;

determining whether the imbalance metric exceeds an imbalance threshold;

in response to determining that the imbalance metric exceeds the imbalance threshold;

performing pre-charging balancing;

charging the plurality of battery sub-modules; and

performing post-charging balancing; and

in response to determining that the imbalance metric does not exceed the imbalance threshold;

charging the plurality of battery sub-modules; and

performing post-charging balancing.