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

Patent metadata

Field	Value
Publication number	US-11817727-B2
Application number	US-202117395391-A
Country	US
Kind code	B2
Filing date	Aug 5, 2021
Priority date	Jul 26, 2018
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

One or more battery sub-modules are selected by obtaining at least one voltage from each battery sub-module and selecting based at least in part on the obtained voltages. The battery sub-modules are electrically connected in series in order to provide power to a primary load. Each battery sub-module includes a plurality of cells electrically connected in series and each battery sub-module further includes a battery management system that monitors the cells in that battery sub-module. Those battery management systems in the selected sub-modules are turned off so that the battery management systems in the selected sub-modules do not consume power at least temporarily from the cells in the selected sub-modules while (1) the battery sub-modules are not providing power to the primary load and (2) the battery sub-modules are not being charged.

First claim

What is claimed is:

1. A system, comprising:
a plurality of battery sub-modules, wherein:
the plurality of battery sub-modules are electrically connected in series in order to provide power to a primary load;
each battery sub-module includes a plurality of cells electrically connected in series; and

a controller that is configured to:
select one or more battery sub-modules from the plurality of battery sub-modules, including by:
obtaining at least one voltage from each battery sub-module; and
selecting one or more battery sub-modules based at least in part on the obtained voltages,

wherein the plurality of battery sub-modules include at least one unselected battery sub-module;
wherein each selected battery sub-module is coupled to a secondary load;
configure those secondary loads in the one or more selected battery sub-modules to draw power from the at least one unselected battery sub-module so that the secondary loads coupled to the selected battery sub-modules do not consume power at least temporarily from the plurality of cells in the selected battery sub-modules while (1) the plurality of battery sub-modules is not providing power to the primary load, or (2) the plurality of battery sub-modules is not being charged.

2. The system of claim 1 , wherein each secondary load is powered using a lower voltage than the primary load.

3. The system of claim 1 , wherein at least one secondary load coupled to a battery sub-module includes a battery management system that monitors the plurality of cells in that battery sub-module.

4. The system of claim 1 , wherein selecting the one or more battery_sub-modules is based at least in part on a plurality of minimum cell voltages which includes a minimum cell voltage from each battery sub-module in the plurality of battery sub-modules.

5. The system of claim 1 , wherein selecting the one or more battery sub-modules is based at least in part on a plurality of maximum cell voltages which includes a maximum cell voltage from each battery sub-module in the plurality of battery sub-modules.

6. The system of claim 1 , wherein selecting the one or more battery sub-modules includes:
comparing, for each battery sub-module in the plurality of battery sub-modules, a minimum cell voltage against a voltage threshold in order to identify any battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold; and
selecting one or more of those battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold.

7. The system of claim 1 , wherein the controller is further configured 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, perform pre-charging balancing; and
after performing pre-charging balancing, charge the plurality of battery sub-modules.

8. The system of claim 7 , wherein pre-charging balancing comprises configuring those second loads in the one or more selected battery sub-modules to draw power from the at least one unselected battery sub-module so that the secondary loads coupled to the selected battery sub-modules do not consume power at least temporarily from the plurality of cells in the selected battery sub-modules while (1) the plurality of battery sub-modules is not providing power to the primary load, or (2) the plurality of battery sub-modules is not being charged.

9. The system of claim 1 , further comprising:
an electric aircraft including one or more lift fans, wherein the electric aircraft is powered by the plurality of battery sub-modules, wherein the primary load includes the one or more lift fans.

10. The system of claim 1 , wherein each secondary loads includes one or more of an electronic device, a motor, or a solenoid.

11. The system of claim 1 , wherein the controller is configured to balance voltage levels of the plurality of battery sub-modules.

12. A method, comprising:
selecting one or more battery sub-modules from a plurality of battery sub-modules, including by:
obtaining at least one voltage from each battery sub-module; and
selecting one or more battery sub-modules based at least in part on the obtained voltages, wherein:
the plurality of battery sub-modules are electrically connected in series in order to provide power to a primary load;
each battery sub-module includes a plurality of cells electrically connected in series;

wherein the plurality of battery sub-modules include at least one unselected battery sub-module;
wherein each selected battery sub-module is coupled to a secondary load; and
configuring those secondary loads in the one or more selected battery sub-modules to draw power from the at least one unselected battery sub-module so that the secondary loads coupled to the selected battery sub-modules do not consume power at least temporarily from the plurality of cells in the selected battery sub-modules while (1) the plurality of battery sub-modules is not providing power to the primary load, or (2) the plurality of battery sub-modules is not being charged.

13. The method of claim 12 , wherein each secondary load is powered using a lower voltage than the primary load.

14. The method of claim 12 , wherein at least one secondary load coupled to a battery sub-module includes a battery management system that monitors the plurality of cells in that battery sub-module.

15. The method of claim 12 , wherein selecting the one or more battery_sub-modules is based at least in part on a plurality of minimum cell voltages which includes a minimum cell voltage from each battery sub-module in the plurality of battery sub-modules.

16. The method of claim 12 , wherein selecting the one or more battery sub-modules is based at least in part on a plurality of maximum cell voltages which includes a maximum cell voltage from each battery sub-module in the plurality of battery sub-modules.

17. The method of claim 12 , wherein selecting the one or more battery sub-modules includes:
comparing, for each battery sub-module in the plurality of battery sub-modules, a minimum cell voltage against a voltage threshold in order to identify any battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold; and
selecting one or more of those battery sub-modules with a minimum cell voltage that does not exceed the voltage threshold.

18. The method of claim 12 , further comprising:
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
after performing pre-charging balancing, charging the plurality of battery sub-modules.

19. The method of claim 12 , wherein pre-charging balancing comprises configuring those second loads in the one or more selected battery sub-modules to draw power from the at least one unselected battery sub-module so that the secondary loads coupled to the selected battery sub-modules do not consume power at least temporarily from the plurality of cells in the selected battery sub-modules while (1) the plurality of battery sub-modules is not providing power to the primary load, or (2) the plurality of battery sub-modules is not being charged.

Assignees

• Wisk Aero Llc

Inventors

• Furman Scott
• Hom Lewis Romeo

Classifications

• H02J7/54 Primary

  Passive balancing, e.g. using resistors or parallel MOSFETs · CPC title

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H02J7/667

  disconnection of loads if battery is not under charge, e.g. in vehicle if engine is not running · CPC title

• H02J7/663

  using battery or load disconnect circuits (H02J9/002 takes precedence) · CPC title

• H02J7/575

  Parallel/serial switching of connection of batteries to charge or load circuit · CPC title