Step-time battery degradation determination

• US 10,107,864 B2
• Filed: 04/11/2016
• Issued: 10/23/2018
• Est. Priority Date: 04/11/2016
• Status: Active Grant

• Current Assignee: Inventus Holdings, LLC
• Original Assignee: Inventus Holdings, LLC
• Inventors: Vidhi, Rachana, Alves, Carlos
• Primary Examiner(s): Dickey, Thomas L
• Application Number:
  US15/095,693
• Publication Number:
  US 20170292998A1
• Time in Patent Office: 925 Days
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/387 Determining ampere-hour charge capacity or SoC
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

Various embodiments determine a remaining battery capacity of a battery in an energy storage battery support system. In one embodiment, a battery is operated at a state of charge which may include being charged, being discharged, and being idle. A change in the state of charge is detected after a duration of time. The amount of remaining battery capacity is calculated based upon the duration of time and the state of charge of the battery during the duration of time. The operating, detecting and calculating are repeated until the amount of remaining battery capacity reaches a predetermined value. The remaining battery capacity after the duration of time is calculated using the battery capacity at the beginning of the duration of time. The battery may be used as an energy source in an electric power distribution grid. The battery is replaced when the remaining battery capacity reaches an end-of-useful-life value.

Claims

1. A method of determining a remaining battery capacity of a battery comprising;

operating a battery as an energy source in an electric power distribution grid through a series of states of charge including idle, charging and discharging states;

switching from a first state of charge from one of an idle, charging or discharging state to a different one of the idle, charging or discharging states, after a duration of time;

responsive to the switching, calculating an amount of remaining battery capacity based upon a complete history of accrued battery degradation for the battery including battery degradation accrued during the first state of charge and a type of the first state of charge of the battery;

repeating the operating, switching and calculating for each state in the series of states of charge until the calculated remaining battery capacity is determined to have reached an end-of-life threshold; and

responsive to determining that the calculated remaining battery capacity has reached an end-of-life threshold, replacing the battery with a new battery.

2. The method of claim 1, wherein the amount of remaining battery capacity for each state in the series of states of charge is calculated using the remaining battery capacity of the battery calculated for an immediately preceeding state as an initial battery capacity of the first state.

3. The method of claim 1, wherein the type of the first state of charge determines a formula to use for the calculating.

4. The method of claim 3, wherein the type of state of charge is idle, the formula for calculating the remaining battery capacity is

5. The method of claim 3, wherein the type of state of charge is one of charging or discharging, the formula for calculating the remaining battery capacity is

6. The method of claim 3, wherein b₁ varies for every state of charge and α

remains constant.

7. The method of claim 1, wherein the different state of charge is discharging, the method further comprises:

responsive to determining that the calculated remaining battery capacity has not reached an end-of-life threshold, outputting energy from the remaining battery capacity to a load.

8. The method of claim 7, wherein the load is the electric power distribution grid.

9. The method of claim 7, wherein the energy is output for use by an outside party.

10. The energy storage battery support system of claim 9, wherein the load is the electric power distribution grid.

11. An energy storage battery support system for use in an electric power distribution grid, the energy storage battery support system comprising:

a rechargeable battery;

a load;

an inverter that exchanges energy between the rechargeable battery and the load; and

a controller that;

operates the battery through a series of states of charge including idle, charging and discharging states; and

switches operation from a first state of charge from one of an idle, charging or discharging state to a different one of the idle, charging or discharging states, after a duration of time

a state of charge monitor that;

monitors the operation of the battery;

detects the switch in the state of charge after a duration of time; and

responsive to the switching, calculates an amount of remaining battery capacity based upon a complete history of accrued battery degradation for the battery including battery degradation accrued during the first state of charge and a type of the first state of charge of the battery; and

wherein the controller further controls;

repeating the operating, switching and calculating for each state in the series of states of charge until the calculated remaining battery capacity is determined to have reached an end-of-life threshold; and

responsive to determining that the calculated remaining battery capacity has reached an end-of-life threshold, replacing the battery with a new battery.

12. The energy storage battery support system of claim 11, wherein the state of charge monitor calculates the amount of remaining battery capacity for each state in the series of states of charge using the remaining battery capacity of the battery calculated for an immediately preceeding state as an initial battery capacity of the first state.

13. The energy storage battery support system of claim 11, wherein the type of the first state of charge determines a formula to use for the calculating.

14. The energy storage battery support system of claim 13, wherein the type of state of charge is idle, the formula for calculating the remaining battery capacity is

15. The energy storage battery support system of claim 13, wherein the type of state of charge is one of charging or discharging, the formula for calculating the remaining battery capacity is

16. A computer program product for determining a remaining battery capacity of a battery, the computer program product comprising:

a non-transitory storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

operating a battery as an energy source in an electric power distribution grid through a series of states of charge including idle, charging and discharging states;

switching from a first state of charge from one of an idle, charging or discharging state to a different one of the idle, charging or discharging states, after a duration of time;

responsive to the switching, calculating an amount of remaining battery capacity based upon a complete history of accrued battery degradation for the battery including battery degradation accrued during the first state of charge and a type of the first state of charge of the battery;

repeating the operating, switching and calculating for each state in the series of states of charge until the calculated remaining battery capacity is determined to have reached an end-of-life threshold; and

responsive to determining that the calculated remaining battery capacity has reached an end-of-life threshold, replacing the battery with a new battery.

17. The computer program product of claim 16, wherein the amount of remaining battery capacity for each state in the series of states of charge is calculated using the remaining battery capacity of the battery calculated for an immediately preceeding state as an initial battery capacity of the first state.

18. The computer program product of claim 16, wherein the type of the first state of charge determines a formula to use for the calculating,

the formula for calculating the remaining battery capacity is

19. The computer program product of claim 16, wherein the different state of charge is discharging, the method further comprises:

responsive to determining that the calculated remaining battery capacity has not reached an end-of-life threshold, outputting energy from the remaining battery capacity to a load.

20. The computer program product of claim 19, wherein the energy is output for use by an outside party.