CHARACTERIZING BATTERY DISCHARGE UNDER DIFFERENT LOADS

• US 20130175996A1
• Filed: 01/05/2012
• Published: 07/11/2013
• Est. Priority Date: 01/05/2012
• Status: Abandoned Application

• Current Assignee: iDesign, Inc. (Phase 3 Media LLC)
• Original Assignee: iDesign, Inc. (Phase 3 Media LLC)
• Inventors: Lowy, Juval
• Application Number:
  US13/344,481
• Publication Number:
  US 20130175996A1
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A storage battery may be characterized from measurements of voltage versus time for different loads. Each measurement for a given load value may be fitted to a corresponding discharge function. The corresponding discharge functions may be applied to specific end voltage values to determine discharge time data for given loads. The discharge data may be interpolated to provide additional data points for discharge time to a particular voltage as a function of load. The resulting set of discharge time data may be fit to a discharge time function. The discharge time function may be used to fill in voltage versus time curves for intermediate load values to produce a computer model for time to a particular voltage.

Claims

1. A method for characterizing a storage battery and automatically simulating its behavior, comprising:

a) obtaining a plurality of sets of measurements of voltage on the storage battery versus time for a corresponding plurality of approximately constant load values;

b) using a computer, automatically fitting each set of measurements for a given corresponding load value to a corresponding discharge function;

c) using a computer, automatically applying the corresponding discharge functions to specific end voltage values for the battery to determine a set of discharge time data representing a time for the battery to discharge from a given initial value to a particular end voltage for a given load;

d) using a computer, automatically interpolating the set of discharge data to provide additional data points to produce a plurality of second sets of discharge time data for discharge time to a particular voltage as a function of load;

e) fitting each second set of discharge time data of discharge time to a particular voltage as a function of load to a discharge time function;

f) using a computer, automatically applying the discharge time function to fill in voltage versus time curves for intermediate load values to produce a computer model for time to a particular voltage as a function of load; and

either;

g) storing the model in computer readable form in a computer-readable medium;

or

h) transmitting the model in computer readable from over a network;

or

i) operating a battery-powered device coupled to a computer using the computer model.

2. The method of claim 1, wherein each discharge function is a least squares fit polynomial having coefficients calculated to at least fourteen decimal places.

3. The method of claim 1, wherein the discharge time function is a polynomial up to a cutoff load value and a power function beyond the cutoff load value.

4. The method of claim 1, further comprising determining a battery capacity as a function of load using the computer model.

5. The method of claim 1, wherein applying the discharge time function to fill in voltage versus time curves for intermediate load values includes determining a discharge time for the battery to discharge from the start voltage to a target voltage for a given load, start voltage and target voltage.

6. The method of claim 1, wherein applying the discharge time function to fill in voltage versus time curves for intermediate load values includes determining a target voltage for the battery for a given start voltage and target time.

7. The method of claim 1, wherein applying the discharge time function to fill in voltage versus time curves for intermediate load values includes determining a capacity of the battery for a given load and a target voltage.

10. The method of claim 1 wherein the one or more fitted functions include one or more polynomials or power functions.

11. The method of claim 2 wherein the one or more polynomials or power functions include one or more odd-order polynomials.

12. The method of claim 3 wherein the one or more odd-order polynomials include an odd number of coefficients, wherein each coefficient is determined to fourteen decimal places.

8. A non-transitory computer readable medium having embodied therein computer readable instructions configured to implement a method for characterizing a storage battery upon execution of the instructions, wherein the instructions comprise:

a) one or more instructions configured to obtain a plurality of sets of measurements of voltage on the storage battery versus time for a corresponding plurality of approximately constant load values upon execution by a computer;

b) one or more instructions configured to fit each set of measurements for a given corresponding load value to a corresponding discharge function upon execution by a computer;

c) one or more instructions configured to apply the corresponding discharge functions to specific end voltage values for the battery to determine a set of discharge time data representing a time for the battery to discharge from a given initial value to a particular end voltage for a given load upon execution by a computer;

d) one or more instructions configured to interpolate the set of discharge data to provide additional data points to produce a plurality of second sets of discharge time data for discharge time to a particular voltage as a function of load upon execution by a computer;

e) one or more instructions configured to fit each second set of discharge time data of discharge time to a particular voltage as a function of load to a discharge time function upon execution by a computer;

f) one or more instructions configured to apply the discharge time function to fill in voltage versus time curves for intermediate load values to produce a computer model for time to a particular voltage as a function of load upon execution by a computer; and

one or more instructions configured to either;

g) store the model in computer readable form in a computer-readable medium upon execution by a computer;

or

h) transmit the model in computer readable from over a network upon execution by a computer;

or

i) operate a battery-powered device coupled to a computer using the computer model upon execution by a computer.

9. A method for operating a storage battery, comprising:

obtaining battery characterization information for a given storage battery, wherein the battery characterization information is in the form of a plurality of fitted functions, wherein one or more of the fitted functions in the plurality are derived from measurements of voltage of the battery as a function of time by interpolating between two fitted functions obtained from the measurements;

entering the battery characterization information into a computer program running on a computer; and

(a) entering a load, a start voltage and a target voltage into the computer program and determining with the computer program discharge time for the battery to discharge from the start voltage to the target voltage and operating the battery in accordance with the determined discharge time;

or

(b) entering a load, a start voltage and a target time into the program and determining with the computer program what the target voltage will be for the battery at the target time and operating the battery in accordance with the determined target voltage;

or

(c) specifying a load and a target voltage and determine a capacity of the battery and operating the battery in accordance with the determined capacity.