Estimation device, energy storage apparatus, estimation method, and computer program

An estimation method for estimating an internal state of an energy storage device including a first electrode containing an active material in which repeated charge-discharge changes a first characteristic that is an energy storage amount-potential charge characteristic of the first electrode, and a second characteristic that is an energy storage amount-potential discharge characteristic of the first electrode, the estimation method comprising:

• storing, in a storage unit, a plurality of energy storage amount characteristics that are at least one of first characteristics, second characteristics, third characteristics that are energy storage amount-voltage charge characteristics based on a voltage difference between the first electrode and a second electrode of the energy storage device, fourth characteristics that are energy storage amount-voltage discharge characteristics based on the voltage difference between the first electrode and the second electrode of the energy storage device, and V−dQ/dV, which is a relationship of V, as a potential of the first electrode or a voltage of the energy storage device, with a differential value of Q, as an amount of a charge or a discharge, in correspondence with a change in a feature value, which is changed by repeated charge-discharge, or having stored as a function of the feature value, the feature value including at least one of an amount of a charge capacity or a discharge capacity in a predetermined voltage range, and an average discharge potential;
• acquiring information relating to a part of the third characteristic and/or the fourth characteristic of the energy storage device;
• and
• estimating an internal state of the energy storage device in accordance with the information, and in accordance with the energy storage amount characteristics or the function.

A computer program for causing a computer that estimates an internal state of an energy storage device including a first electrode containing an active material in which repeated charge-discharge changes a first characteristic that is an energy storage amount-potential charge characteristic of the first electrode, and a second characteristic that is an energy storage amount-potential discharge characteristic of the first electrode, to execute processing of:

• acquiring information relating to a part of a third characteristic that is an energy storage amount-voltage charge characteristic based on a voltage difference between the first electrode and a second electrode of the energy storage device and/or a fourth characteristic that is an energy storage amount-voltage discharge characteristic based, on the voltage difference between the first electrode and the second electrode of the energy storage device;
• referring to a table that stores a plurality of energy storage amount characteristics that are at least one of first characteristics, second characteristics, third characteristics, fourth characteristics, and V−dQ/dV, which is a relationship of V, as a potential of the first electrode or a voltage of the energy storage device, with a differential value of Q, as an amount of a charge or a discharge, in correspondence with a change in a feature value, or referring to a function of the feature value, the feature value including at least one of an amount of a charge capacity or a discharge capacity in a predetermined voltage range, and an average discharge potential;
• and
• estimating an internal state of the energy storage device in accordance with the information, and in accordance with the energy storage amount characteristics or the function.