Battery diagnostic device and method thereof

A battery diagnosis device, comprising:

• a measuring device configured to measure status values of a formed battery;
• a charge and discharge device configured to charge and discharge the formed battery over a plurality of cycles;
• and
• a control device configured to detect a discharge capacity in each cycle of the plurality of cycles based on the status values measured in each cycle, detect an initial capacity increase amount of the formed battery based on a difference in discharge capacity between two cycles among the plurality of cycles, detect a negative electrode undischarged capacity of the formed battery based on the discharge capacity in at least one cycle among the plurality of cycles, and diagnose a formation status of the formed battery based on the initial capacity increase amount and the negative electrode undischarged capacity and output a diagnosis result,
• wherein, based on the diagnosis result, the control device is configured to invoke a second formation of the formed battery.