Battery charging/discharging apparatus and battery charging/discharging method

• US 6,828,761 B1
• Filed: 09/09/2003
• Issued: 12/07/2004
• Est. Priority Date: 06/16/2000
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Sato, Hideyuki, Suzuki, Mamoru
• Primary Examiner(s): Tibbits, Pia
• Application Number:
  US10/658,931
• Time in Patent Office: 455 Days
• Field of Search: 320/132, 320/155, 324/427, 340/636.1, 340/7.32, 340/7.37, 340/7.38, 455/67.11, 455/67.7, 455/127.1, 455/127.5, 455/95, 455/226.1
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• 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: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

When a battery is in a standby mode, a microcomputer switches to a sleep mode when no charging/discharging current is supplied within a predetermined time and controls a timer to start measuring the standby time of the battery. When a charging/discharging current is supplied, the microcomputer switches to a wake-up mode and controls the timer to stop measuring the standby time. Then, the microcomputer reads the measured standby time. Based on the read standby time, the microcomputer calculates the correction value to correct the currently stored remaining battery capacity value.

Claims

1. A battery charging/discharging apparatus for determining a remaining capacity of a battery, comprising:

measuring means for measuring a standby time during which the battery is in a standby mode;

correction value calculating means for calculating a correction value for the remaining capacity of the battery based on the standby time measured by said measuring means;

correcting means for correcting a present remaining capacity value of the battery based on the correction value calculated by said correction value calculating means; and

determining means for determining whether the standby time has reached a predetermined time,

wherein said correction value calculating means calculates the correction value for the remaining capacity of the battery at a predetermined time interval based on a result of said determining means.

2. A battery charging/discharging method of a battery charging/discharging apparatus for determining a remaining capacity of a battery, said battery charging/discharging method comprising the steps of:

measuring a standby time during which the battery is in a standby mode;

calculating a correction value for the remaining capacity of the battery based on the standby time measured in the measuring step;

correcting a present remaining capacity value of the battery based on the correction value calculated in the calculating step; and

determining whether the standby time has reached a predetermined time,

wherein said step of calculating a correction value calculates the correction value for the remaining capacity of the battery at a predetermined time interval based on a result of said determining step.

3. Apparatus for determining a remaining capacity of a battery, the apparatus comprising:

a cell voltage detector for detecting a cell voltage;

a microcomputer for calculating a remaining battery capacity value based on a detected cell voltage from the cell voltage detector;

a memory for storing the remaining battery capacity value calculated by the microcomputer; and

a timer under control of the microcomputer for counting time,

wherein when the microcomputer determines that the battery has been in a charge/discharge mode within a predetermined time as counted by the timer the cell voltage is detected by the cell voltage detector and the remaining battery capacity is read out from the memory and compared by the microcomputer with the newly detected cell voltage and when the remaining battery capacity value is greater, the newly detected cell voltage is used as an up-to-date remaining battery capacity value that is then stored in the memory.

4. A method employing a microcomputer for determining a remaining capacity of a battery, the method comprising the steps of:

detecting a battery voltage and storing the detected voltage as a remaining battery capacity value in a memory of the microcomputer;

determining whether the battery has not been in a charge/discharge mode within a predetermined period of time as counted by a timer;

upon a determination in the step of determining that the battery has been in the charge/discharge mode within the predetermined period of time, newly detecting the battery voltage;

reading the remaining battery capacity value from the memory;

comparing the read-out remaining battery capacity value with the newly detected battery voltage;

upon a comparison result that the read-out remaining battery capacity value is greater, using the newly detected battery voltage as an updated remaining battery capacity vale; and

replacing the remaining battery capacity value stored in the memory with the updated remaining battery capacity value.