Method of Evaluating Remaining Power of a Battery for Portable

• US 20140005965A1
• Filed: 05/27/2010
• Published: 01/02/2014
• Est. Priority Date: 05/27/2010
• Status: Abandoned Application

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Ruutu, Jussi Pekka Olavi, Vestama, Mikael Martti Vaino
• Application Number:
  US13/699,115
• Publication Number:
  US 20140005965A1
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A remaining energy E of a battery is estimated based on a measurement of a momentary voltage and a momentary current. E is defined as a function of its voltage U or power owing to a characteristic function (E/U) or (E/P). Instead of the function, a lookup table can be used. E/U function is defined by using a reference battery having the same or similar characteristics. A set of low and high current or power loads are applied to the reference battery to cause voltage drops which are measured and then used to determine function (E/U) and a parameter Alpha which is specific to the type of reference battery. During the operation of the battery, momentary voltage and current are measured and Alpha is used to correct the momentary voltage. Afterwards, function (E/U) enables to estimate E. The battery size is used to scale E for a better estimation.

Claims

1. A method comprising:

measuring a momentary voltage of a battery having one or more specific parameters;

measuring a momentary current of the battery;

providing a corrected voltage based on the measured momentary voltage and the momentary current and the one or more specific parameters; and

providing an amount of available energy E in the battery based on a function f1 of the corrected voltage and the one or more specific parameters.

2. The method of claim 1 wherein the corrected voltage U is defined by:

U=Vbat+(Vbat×

Ibat)/Alpha;

where Vbat is the measured momentary voltage;

Ibat is the measured momentary current; and

Alpha is one of the specific parameters.

3. The method of claim 2 wherein Alpha is either a constant or polynomial function.

4. The method of claim 1 wherein the function f1 is determined by measuring a set of voltage drops'"'"' of a reference battery having same or similar specific parameters, the set of voltage drops resulting from :

constant and low power consumptions of the reference battery, in idle state; and

higher power consumptions of the reference battery in active state.

5. The method of claim 4 further comprising:

scaling the amount of available energy E in the battery based on a nominal capacity B_size of the reference battery with a scaling factor to provide a scaled amount of available energy E_est.

6. The method of claim 5 further comprising:

averaging the scaled amount of energy available in the battery over time in order to provide a more accurate value by using an exponentially moving average function.

7. The method of claim 4 wherein the function f1 is a mathematical function which varies on four ranges of values:

if the corrected voltage U is above approximately 4.12 Volts, then the battery is fully charged and the amount of available energy E is a maximum value;

if the corrected voltage U is between approximately 3.58 Volts and 4.12 Volts, the amount of available energy E is a first polynomial function of the corrected voltage U;

if the corrected voltage is between approximately 3.2 Volts and 3.58 Volts, then the amount of available energy E is second polynomial function of the corrected voltage U; and

if corrected value is below approximately 3.2 Volts, then the amount of available energy E is 0 Joule.

8. The method of claim 4 wherein the function f1 is a mathematical function which varies on more than 4 ranges of values depending on the one or more specific parameters.

9. The method of claim 1 wherein the powered device has more than one battery with the same or similar specific parameters.

10. The method of claim 9 wherein the batteries have different specific parameters.

11. The method of claim 9 wherein the batteries are connected in series or parallel.

12. The method of claim 1 wherein the function f1 is a look up table showing the relation between the amount of available energy and the corrected voltage.

13. An apparatus comprising:

an energy management circuitry of at least one battery having one or more specific parameters configured;

to measure a momentary voltage and a momentary current of each of the at least one battery;

to provide a corrected voltage U of each of the at least one battery based on the measured momentary voltage, the momentary current and the one or more specific parameters; and

to provide an amount of available energy E in at least one of the at least one battery, each amount of available energy E being based on a function f1 of the corresponding corrected voltage U and the one or more specific parameters.

14. The apparatus of claim 13, wherein the corrected voltage U is defined by:

U=Vbat+(Vbat×

Ibat)/Alpha;

where Vbat is the measured momentary voltage;

That is the measured momentary current; and

Alpha is one of the specific parameters.

15. The apparatus of claim 13 wherein each function f1 is determined by measuring a set of voltage drops of a reference battery having same or similar specific parameters as the at least one battery, the set of voltage drops resulting from:

constant and low power consumptions of the corresponding reference battery, in idle state; and

higher power consumptions of the corresponding reference battery, in active state.

16. The apparatus of claim 13 wherein the energy management circuitry further comprises at least a processor configured to perform mathematical functions to compute the amount of available energy E in each of the at least one battery.

17. The apparatus of claim 15 wherein the energy management circuitry is further configured:

to scale the amount of available energy E in the at least one battery according to a nominal capacity B_size of the corresponding reference battery with a scaling factor to provide a scaled amount of available energy E_est of the at least one battery; and

to average the scaled amount of energy available in the at least one battery over time in order to provide a more accurate value by using an exponentially moving average function.

18. A method comprising:

applying a set of low and constant power consumptions to a battery;

measuring a first set of voltage drops of the battery respectively resulting from the set of low and constant power consumptions;

applying a set of high power consumption to the battery;

measuring a second set of voltage drops of the battery respectively resulting from the set of high power consumptions; and

determining a parameter alpha specific to the battery by correlating the power consumption applied to the battery with the resulting voltage drops.

19. The method of claim 18 wherein the parameter alpha is either a constant or polynomial function.

20. A computer-readable medium encoded with instruction that, when executed by a computer, perform:

measuring a momentary voltage of a battery having one or more specific parameters;

measuring a momentary current of the battery;

providing a corrected voltage based on the measured momentary voltage and the momentary current and the one or more specific parameters; and

providing an amount of available energy E in the battery based on a function f1 of the corrected voltage and the one or more specific parameters.