BATTERY DIAGNOSTIC DEVICE, BATTERY DIAGNOSTIC METHOD, BATTERY DIAGNOSTIC PROGRAM, AND VEHICLE

A battery diagnostic device for diagnosing a state of a battery mounted on a vehicle includes: an acquisition unit that acquires a physical quantity indicating the state of the battery; a setting unit that sets one diagnostic model from two or more diagnostic models based on the physical quantity acquired by the acquisition unit; and an estimation unit that estimates a deterioration state of the battery based on the one diagnostic model set by the setting unit.