METHOD AND APPARATUS FOR CONFIRMING THE CHARGE AMOUNT AND DEGRADATION STATE OF A BATTERY, A STORAGE MEDIUM, AN INFORMATION PROCESSING APPARATUS, AND AN ELECTRONIC APPARATUS

• US 20090024339A1
• Filed: 08/27/2008
• Published: 01/22/2009
• Est. Priority Date: 11/26/2003
• Status: Active Grant

• Current Assignee: Toyo System Co., Ltd.
• Original Assignee: Toyo System Co., Ltd.
• Inventors: SHOJI, Hideki
• Granted Patent: US 7,974,797 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery

Abstract

A method and apparatus is used to confirm the charge amount and degradation state of a battery. Various cycle test battery measurements are conducted at prescribed time intervals until the end of the battery life, and the measured values are used to generate a determination table or determination tables showing relationships between battery charge amount and degradation state. To establish the charge amount and degradation state of a subject battery, the subject battery is measured and the results compared with determination table values. The existing charge amount and the state of battery degradation are estimated in accordance with a determination table location of matching values.

Claims

1. A method of confirming battery charge amount and degradation state, comprising the steps of:

measuring at a plurality of battery temperatures a cycle test battery at predetermined time intervals substantially until battery end of life, using measurement values of at least two selected from battery open voltage, current and voltage during discharge, and current and voltage during charging;

using measured values to generate determination tables showing relationships in each case between prescribed charge amounts and prescribed degradation states;

measuring a subject battery in respect of said at least two selected from battery open voltage, current and voltage during discharge, and current and voltage during charging; and

comparing determination table values with each of measured values of the subject battery to confirm present subject battery charge amount and degradation state in accordance with determination table locations of matching values, and simultaneously using an incidence of appearance at determination table locations resulting from the measured values to estimate present subject battery charge amount and degradation state.

2. The method according to claim 1, in which a value of the battery open voltage is an average value of measurements made at fixed time intervals.

3. The method according to claim 1, in which the measurement of the voltage and current during discharge in a constant current discharge circuit comprises the steps of:

measuring battery voltage;

after discharge starts, measuring battery voltage a plurality of times at fixed time intervals;

measuring discharge current a plurality of times at fixed time intervals simultaneously with the step of measuring battery voltage a plurality of times; and

after terminating the discharge, measuring battery voltage a plurality of times at fixed time intervals.

4. The method according to claim 1, in which the measurement of battery voltage and current during discharge, and a measurement of time, in a constant current, constant voltage discharge circuit comprise the steps of:

measuring battery voltage;

subtracting a predetermined voltage from the measured battery voltage to set a constant voltage discharge value;

measuring a time from a start of the discharge until the set constant voltage discharge value is attained;

after the start of the discharge, measuring discharge current a plurality of times at fixed time intervals; and

terminating the discharge.

5. The method according to claim 1, in which the measurement of current and voltage during constant current charging comprises the steps of:

measuring battery voltage;

after the step of measuring the battery voltage, starting the charging and measuring battery voltage when the charge current is changed a plurality of times at fixed time intervals;

measuring the charge current when the charge current is changed a plurality of times at fixed time intervals; and

terminating the charging.

6. The method according to claim 1, in which the measurement of current and voltage, and a measurement of time, during constant current, constant voltage charging comprise the steps of:

measuring battery voltage;

adding a predetermined voltage to the measured battery voltage to set a constant voltage charging value;

starting the charging after setting the constant voltage charging value;

measuring a time at which the set constant voltage charging value is attained;

measuring the charge current a plurality of times at fixed time intervals; and

terminating the charging.

7. The method according to claim 1, in which ambient temperature during the step of measuring the cycle test battery to generate the determination table and during the step of measuring the subject battery, is measured a plurality of times at fixed time intervals.

8. The method according to claim 2, in which ambient temperature during the step of measuring the cycle test battery to generate the determination table and during the step of measuring the subject battery, is measured a plurality of times at fixed time intervals.

9. The method according to claim 3, in which ambient temperature during the step of measuring the cycle test battery to generate the determination table and during the step of measuring the subject battery, is measured a plurality of times at fixed time intervals.

10. The method according to claim 4, in which ambient temperature during the step of measuring the cycle test battery to generate the determination table and during the step of measuring the subject battery, is measured a plurality of times at fixed time intervals.

11. The method according to claim 5, in which ambient temperature during the step of measuring the cycle test battery to generate the determination table and during the step of measuring the subject battery, is measured a plurality of times at fixed time intervals.

12. The method according to claim 6, in which ambient temperature during the step of measuring the cycle test battery to generate the determination table and during the step of measuring the subject battery, is measured a plurality of times at fixed time intervals.