Accumulator device, and state of charge evaluation apparatus and method for accumulator

An accumulator device, comprising:

• an accumulator and a state of charge evaluation apparatus for the accumulator;
• a terminal voltage measurement unit configured to measure a terminal voltage of the accumulator;
• a current measurement unit configured to measure a current flowing in the accumulator;
• a first transition measurement unit configured to measure a total charging and discharging amount (Ah), a deterioration degree or an elapsed time from a time of first use of the accumulator, wherein the deterioration degree is an amount of deterioration of accumulator total capacity that varies over time depending on operational conditions for the accumulator;
• first multi-dimensional characteristic models in which a plurality of relational models each between the terminal voltage, current and a state of charge during charging are prepared for each of deterioration degrees;
• a first selecting means configured to select a characteristic model from among the first multi-dimensional characteristic models in accordance with the total charging and discharging amount (Ah), the deterioration degree or the elapsed time measured by the first transition measurement unit;
• a first estimation unit configured to estimate the state of charge from the characteristic model selected by the first selecting means;
• a second transition measurement unit configured to measure a transition time from a time of equal charging to a time when the accumulator is fully charged by equal charging or the total charging and discharging amount (Ah) from a time of equal charging to a time when the accumulator is fully charged by equal charging;
• second multi-dimensional characteristic models in which a plurality of relational models each between the terminal voltage, current and the state of charge during discharging are prepared for each of the deterioration degrees;
• a second selecting means configured to select a characteristic model from among the second multi-dimensional characteristic models in accordance with the total charging and discharging amount (Ah), the deterioration degree or the elapsed time measured by the first transition measurement unit;
• a second estimation unit configured to estimate the state of charge from the characteristic model selected by the second selecting means;
• a third estimation unit configured to estimate the state of charge from current accumulation;
• a weight determining means configured to determine respective weights to be imparted to the outputs of the first estimation unit and the second estimation unit and to an output of the third estimation unit from the transition time or the total charging and discharging amount (Ah) from the time when the accumulator is fully charged by equal charging obtained by the second transition measurement unit;
• and
• a determining means configured to finally determine the state of charge in accordance with the outputs of the first estimation unit, the second estimation unit, and the third estimation unit that are produced in consideration of the weights determined by the weight determining means.