Method and apparatus for soft-sensor characterization of batteries

• US 20050052810A1
• Filed: 11/29/2002
• Published: 03/10/2005
• Est. Priority Date: 12/03/2001
• Status: Active Grant

• Current Assignee: Intellectual Ventures Fund 10 LLC (Intellectual Ventures LLC)
• Original Assignee: Intellectual Ventures Fund 10 LLC (Intellectual Ventures LLC)
• Inventors: Tenno, Ander, Tenno, Robert, Suntio, Teuvo
• Granted Patent: US 7,711,538 B2
• Time in Patent Office: Days
• US Class Current: 361/115
• CPC Class Codes: H01M 10/12 Construction or manufacture
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• 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 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method and apparatus are disclosed for simulating the operation of a rechargeable battery. There is obtained (503, 553) a value for at least one parameter that describes an internal state of the battery. Said obtained value is used for calculating (504, 505, 554, 555) a prediction value for a characteristic of the battery that is observable outside the battery. These steps are repeated a multitude of times in order to simmulate the operation of the battery over a certain period of time. A difference is detected (507, 556) between a calculated prediction value and a known value of a corresponding characteristic in a corresponding situation. The obtained value of said at least one parameter is corrected (507, 558) before a further prediction value calculating step by an amount that is proportional to said detected difference.

Claims

1. A method for simulating the operation of a rechargeable battery, comprising the steps of:

a) obtaining (503, 553) a value for at least one parameter that describes an internal state of the battery,

b) calculating (504, 505, 554, 555), by using said obtained value, a prediction value for a characteristic of the battery that is observable outside the battery and

c) repeating steps a) and b) multitude of times in order to simulate the operation of the battery over a certain period of time,

characterized in that it comprises the steps of detecting (507, 556) a difference between a calculated prediction value and a known value of a corresponding characteristic in a corresponding situation, and correcting (507, 558) the obtained value of said at least one parameter before a further prediction value calculating step by an amount that is proportional to said detected difference.

2. A method according to claim 1, characterized in that step b) comprises the substeps of:

calculating (505, 555) a ;

prediction value for a first characteristic of the battery that is observable outside the battery,

calculating (505, 555) a second prediction value for a second characteristic of the battery that is observable outside the battery, so that;

said first prediction value is used for the steps of detecting (507, 556) a difference between a calculated prediction value and a known value of a corresponding first characteristic in a corresponding situation, and correcting (507, 558) the obtained value of said at least one parameter before a further prediction value calculating step by an amount that is proportional to said detected difference, and

said second prediction value is used as a criterion (506, 559) for continuing or discontinuing the repetition according to step c).

3. A method according to claim 2, characterized in that the first prediction value is an electric current value that is used for detecting (507, 556) a difference between it and a known value of a current drawn from the battery and the second prediction value is a voltage value that is used to determine (506, 559), whether the battery would be still capable of sustaining the supply of electric energy to a load at the moment of time represented by the present calculation step.

4. A method according to claim 2, characterized in that the steps of

detecting (556) a difference between a calculated first prediction value and a known value of a corresponding first characteristic in a corresponding situation, and

correcting (558) the obtained value of said at least one parameter before a further prediction value calculating step by an amount that is proportional to said detected difference

are performed until the detected difference is smaller (557) than a predetermined limiting value, and only thereafter there is performed the step of calculating a second prediction value for a second characteristic of the battery that is observable outside the battery.

5. A method according to claim 1, characterized in that as an initialization for step a) it comprises the steps of:

discharging (402) and recharging (403) the battery under controlled conditions,

measuring (402, 403) a voltage over the battery, a current through the battery and temperature of the battery during said discharging and recharging, and

using measured voltage, current and temperature as references (404) for finding most appropriate initial values for certain parameters that describe internal conditions of the battery;

and during the repetition according to step c) the step of obtaining (503, 553) a parameter value in step a) involves simulating the development over time of said internal conditions of the battery.

6. An apparatus for simulating the operation of a rechargeable battery (601, 602, 603, 604), comprising:

means (616) for obtaining values for parameters that describe an internal state of the battery,

means (616) for calculating by using said obtained values, prediction values for characteristics of the battery that are observable outside the battery;

said means (616) being adapted to perform repetitive steps of obtaining values for parameters and calculating prediction values in order to simulate the operation of the battery over a certain period of time,

characterized in that it comprises means (616) for detecting a difference between a calculated prediction value and a known value of a corresponding characteristic of the battery in a corresponding situation, and means (616) for correcting an obtained value of a parameter before calculating a further prediction value by an amount that is proportional to a detected difference.

7. An apparatus according to claim 6, characterized in that comprises:

a battery (601, 602, 603, 604),

voltage measuring means (611, 612, 613, 614) for measuring a voltage over said battery,

electric current measuring means (615) for measuring a current through said battery,

temperature measuring means (606) for measuring a temperature of said battery,

a load (623) that is controllably couplable to the battery for discharging said battery through said load,

a power source (622) that is controllably couplable to the battery for recharging said battery, and

a computer (616) that is coupled to receive information from said voltage measuring means (611, 612, 613, 614), electric current measuring means (615) and temperature measuring means (606);

wherein said computer (616) is adapted to;

calculate a first prediction value for a current through the battery,

calculate a second prediction value for a voltage over the battery,

use said first prediction value for detecting a difference between a calculated prediction value and a known value of a current through the battery, and correct the obtained value of said at least one parameter before a further prediction value calculating step by an amount that is proportional to said detected difference, and

use said second prediction value as a criterion for determining, whether the battery would be still capable of sustaining the supply of electric energy to a load at the moment of time represented by the present calculation step.

8. An apparatus according to claim 7, characterized in that the computer (616) is adapted to initiate a cycle of controllably discharging the battery through said load (623) and recharging the battery from said power source (622), and to store information received from said voltage measuring means (611, 612, 613, 614), electric current measuring means (615) and temperature measuring means (606) during such a cycle of controllably discharging and recharging, and to use the stored voltage, current and temperature information as references for finding most appropriate initial values for certain parameters that describe internal conditions of the battery.