Battery Diagnosis Device, Battery Diagnosis Method, Battery Pack, and Electric Vehicle

A battery diagnosis apparatus according to the present disclosure includes a voltage sensor to generate a voltage signal indicating a battery voltage of a battery; a current sensor to generate a current signal indicating a battery current flowing through the battery; and a control circuit. The control circuit determines a measured capacity curve over a predetermined set voltage range based on the voltage signal and the current signal collected at each unit time for a constant current period during which the battery is charged or discharged at a predetermined current rate over the set voltage range. The control circuit determines a measured differential curve over the set voltage range based on the measured capacity curve. The control circuit determines whether a negative electrode tortuosity of the battery abnormally increased by comparing the measured differential curve with a reference differential curve.