BATTERY DIAGNOSIS DEVICE, BATTERY MANAGEMENT SYSTEM, BATTERY PACK, ELECTRIC VEHICLE, AND BATTERY DIAGNOSIS METHOD

A battery diagnosis device for a battery including a parallel connection structure of unit cells according to an aspect of the present disclosure includes a data acquisition unit configured to collect charge/discharge data including a voltage time series indicating a time-dependent change of a voltage across the battery and a current time series indicating a time-dependent change of a charge/discharge current flowing through the battery; and a data processing unit configured to determine an estimated capacity value indicating a full charge capacity of the battery based on the charge/discharge data. The data processing unit is configured to diagnose an abnormality in the parallel connection structure by monitoring a time-dependent change of the estimated capacity value.