State detecting method and state detecting device of secondary battery

A state detecting device of a secondary battery, comprising:

• voltage acquiring means for acquiring a detected voltage value of the secondary battery;
• current acquiring means for acquiring a detected current value of the secondary battery;
• state quantities caused by variation acquiring means for acquiring a temperature and at least one of state quantities caused by variation that impact a state of charge of the secondary battery;
• and
• a state of charge calculating unit that determines that the secondary battery has reached a predetermined charge state and calculates the state of charge using the detected voltage value and the detected current value acquired by the voltage acquiring means and the current acquiring means;
• the state of charge calculating unit comprising correcting means for making corrections using a combination of the temperature and the state quantities caused by variation, at least one of the state quantities being selected from a group consisting of a stratification degree, battery capacity, battery fluid volume, battery weight and battery volume.

A state detecting device of a secondary battery, comprising:

• a voltage acquiring unit for acquiring a detected voltage value while the secondary battery is being charged;
• a current acquiring unit for acquiring a first detected current value;
• a state quantity acquiring unit for acquiring at least one of state quantities caused by variation that impact a state of charge of the secondary battery;
• and
• a state of charge calculating unit for calculating the state of charge using the detected voltage value and the first detected current value for determining that the secondary battery has reached a predetermined charge state, the state of charge calculating unit performing the tasks of:
• determining that the detected voltage value is at least a predetermined voltage threshold value;
• determining that the first detected current value is at most a predetermined current threshold value;
• determining that a predetermined time has elapsed after it has been determined that the detected voltage value is at least the predetermined voltage threshold value and that the detected current value is at most the predetermined current threshold value;
• setting the state of charge to a predetermined desired charge level after it has been determined that the predetermined time has elapsed to provide a desired state of charge;
• correcting the desired state of charge using the state quantities caused by variation to provide a corrected sate of charge;
• correcting the predetermined current threshold value that corresponds the desired state of charge using the state quantities caused by variation to provide a corrected predetermined current threshold value;
• acquiring a second detected current value from the current acquiring unit;
• and
• determining that the second detected current value is at most the corrected current threshold value.