Battery safety evaluation apparatus, battery safety evaluation method, non-transitory storage medium, control circuit, and power storage system

A battery safety evaluation method comprising:

• estimating an estimation value of a present deterioration state of a first battery and an estimation value of a present SOC of the first battery on the basis of data of voltage and current of the first battery measured in charging or discharging the first battery;
• estimating, on the basis of first reference data, a calorific value of the first battery in an occasion when an external temperature changes;
• and
• calculating, on the basis of the calorific value of the first battery, a safety index regarding a temperature of the first battery in the occasion when the external temperature changes, wherein
• the first reference data is selected as corresponding to the first battery from a plurality of reference data at least indicating relationship between a calorific value of a secondary battery and an external temperature, on the basis of the estimation value of the present deterioration state of the first battery and the estimation value of the present SOC of the first battery.

A non-transitory storage medium storing a computer program comprising:

• estimating an estimation value of a present deterioration state of a first battery and an estimation value of a present SOC of the first battery on the basis of data of voltage and current of the first battery measured in charging or discharging the first battery;
• estimating, on the basis of first reference data, a calorific value of the first battery in an occasion when an external temperature changes;
• and
• calculating, on the basis of the calorific value of the first battery, a safety index regarding a temperature of the first battery in the occasion when the external temperature changes, wherein
• the first reference data is selected as corresponding to the first battery from a plurality of reference data at least indicating relationship between a calorific value of a secondary battery and an external temperature, on the basis of the estimation value of the present deterioration state of the first battery and the estimation value of the present SOC of the first battery.

A control circuit comprising:

• a battery state estimator configured to estimate an estimation value of a present deterioration state of a first battery and an estimation value of a present SOC of the first battery on the basis of data of voltage and current of the first battery measured in charging or discharging the first battery;
• a calorific value estimator configured to estimate, on the basis of first reference data, a calorific value of the first battery in an occasion when an external temperature changes;
• and
• a safety index calculator configured to calculate, on the basis of the calorific value of the first battery, a safety index regarding a temperature of the first battery in the occasion when the external temperature changes, wherein
• the first reference data is selected as corresponding to the first battery from a plurality of reference data at least indicating relationship between a calorific value of a secondary battery and an external temperature, on the basis of the estimation value of the present deterioration state of the first battery and the estimation value of the present SOC of the first battery.

A power storage system comprising:

• a first battery which is a secondary battery to be evaluated;
• and
• a battery safety evaluation apparatus configured to evaluate safety of the first battery, wherein
• the battery safety evaluation apparatus includes:
• a battery state estimator configured to estimate an estimation value of a present deterioration state of a first battery and an estimation value of a present SOC of the first battery on the basis of data of voltage and current of the first battery measured in charging or discharging the first battery;
• a calorific value estimator configured to estimate, on the basis of first reference data, a calorific value of the first battery in an occasion when an external temperature changes;
• and
• a safety index calculator configured to calculate, on the basis of the calorific value of the first battery, a safety index regarding a temperature of the first battery in the occasion when the external temperature changes, and
• the first reference data is selected as corresponding to the first battery from a plurality of reference data at least indicating relationship between a calorific value of a secondary battery and an external temperature, on the basis of the estimation value of the present deterioration state of the first battery and the estimation value of the present SOC of the first battery.