Dynamic adjustment of capacity threshold for a battery unit

• US 10,283,987 B1
• Filed: 02/06/2018
• Issued: 05/07/2019
• Est. Priority Date: 02/06/2018
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Wang, Ligong, Frink, Darin Lee
• Primary Examiner(s): La, Anh V
• Application Number:
  US15/889,630
• Time in Patent Office: 455 Days
• Field of Search: 34063616, 3406361, 34063612, 34063613, 34063617, 34063619, 3406362, 340635
• CPC Class Codes: G01R 19/04 Measuring peak values or amplitude or envelope of ac or of pulses
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems

Abstract

Described herein is a smart battery unit capable of assessing its suitability to support a particular load. In some embodiments, the battery unit may receive an indication of power requirements for the particular load with respect to a period of time and may evaluate a total electrical capacity that would be required to support such a load based on those power requirements. The battery backup unit may monitor and dynamically update a full-charge capacity value related to its battery cells as well as the capacity requirement related to the load. The two values may then be compared to determine whether the battery backup unit is capable of supporting the load. If the full-charge capacity value is less than the capacity requirement for the load, then the battery unit may determine that it is not suitable for that load.

Claims

1. A battery backup unit, comprising:

a current sensor;

one or more battery cells;

a battery management unit that comprises a processor and a memory including instructions that, when executed with the processor, cause the battery management unit to, at least;

receive, from the current sensor, information related to a current to or from the one or more battery cells;

determine, based on the information related to the current, a full-charge capacity value for the one or more battery cells;

receive a power requirement for a load supported by the battery backup unit, the power requirement for the load comprising an amount of energy consumed by the load during some preceding period of time;

determine, based on the power requirements, a capacity threshold to be associated with the load that comprises an amount of energy required by the load over a predetermined period of time, wherein the capacity threshold is a product of the power requirement for the load and the predetermined period of time;

compare the full-charge capacity value for the one or more battery cells to the capacity threshold associated with the load; and

upon determining that the full-charge capacity value for the one or more battery cells is less than the determined capacity threshold associated with the load, provide an indication that the battery backup unit is insufficient to power the load.

2. The battery backup unit of claim 1, wherein the full-charge capacity value associated with the one or more battery cells is determined based on information related to the current to or from the one or more battery cells during a charge or discharge cycle.

3. The battery backup unit of claim 1, wherein the battery management unit is implemented on an integrated circuit.

4. The battery backup unit of claim 1, wherein the power requirement for the load comprises a peak current consumed by the load during the preceding period of time.

5. The battery backup unit of claim 1, wherein the predetermined period of time corresponds to an average or maximum amount of time for which temporary power outages have occurred over the preceding period of time.

6. A method comprising:

determining, based on information related to a current to or from a battery cell, a full-charge capacity value associated with the battery cell;

receiving a power requirement for a load supported by the battery cell based on an amount of energy consumed by the load during some preceding period of time;

determining, based on the power requirements, a capacity threshold to be associated with the load by multiplying the power requirement for the load by a desired support time;

comparing the full-charge capacity value associated with the battery cell to the capacity threshold associated with the load; and

upon determining that the full-charge capacity value associated with the battery cell is less than the determined capacity threshold associated with the load, providing an indication that a battery backup unit that includes the battery cell is insufficient to power the load.

7. The method of claim 6, wherein providing the indication that the battery backup unit is insufficient to power the load comprises activating an LED.

8. The method of claim 6, wherein the providing the indication that the battery backup unit is insufficient to power the load comprises transmitting a signal to an external electronic device.

9. The method of claim 6, wherein the current to or from the battery cell is obtained via a current sensor.

10. The method of claim 6, wherein the current to or from the battery cell is determined during either a charge cycle or discharge cycle of the battery cell.

11. The method of claim 6, wherein the power requirement comprises a highest current consumed by the load within some preceding period of time.

12. A power system comprising:

a battery unit supporting a load, the battery unit comprising a battery cell and a battery management unit configured to;

receive an indication of a power requirement of the load based on an amount of current consumed by the load within a preceding period of time;

determine, based on the power requirement of the load, a capacity threshold value for the load by multiplying the power requirement of the load by a predetermined period of time;

determine a full-charge capacity value associated with the battery cell;

compare the full-charge capacity value to the capacity threshold value; and

upon determining that the full-charge capacity value is less than the capacity threshold value, providing an indication that the battery unit is insufficient to support the load.

13. The power system of claim 12, further comprising a power supply unit between the load and the battery unit, and wherein the indication of the power requirement of the load is received from the power supply unit.

14. The power system of claim 13, wherein the power requirement of the load received from the power supply unit is based on the highest current consumed by the load within the preceding period of time.

15. The power system of claim 13, wherein the power requirement of the load received from the power supply unit is based on an average current consumed by the load within the preceding period of time.

16. The power system of claim 12, further comprising a power system controller, and wherein the indication of the power requirement of the load is received from the power system controller.

17. The power system of claim 12, further comprising a fuel gauge, and wherein the full-charge capacity value associated with the battery cell is determined by the fuel gauge.

18. The power system of claim 13, wherein the predetermined period of time is received from the power supply unit.