BATTERY DIAGNOSTIC DEVICE, METHOD, PROGRAM, AND VEHICLE

A battery diagnostic device includes a first discharge process unit that performs a first diagnostic discharge, a first determination unit that determines whether a deterioration diagnosis of the battery is possible based on a physical quantity indicating the state of the battery during the first diagnostic discharge acquired by a first acquisition unit, a second discharge process unit that performs a second diagnostic discharge when it is determined that the deterioration diagnosis of the battery is impossible, and a diagnosis unit that performs the deterioration diagnosis of the battery based on the physical quantity acquired by the first acquisition unit when it is determined that the deterioration diagnosis of the battery is possible, and performs the deterioration diagnosis of the battery based on a physical quantity indicating the state of the battery during the second diagnostic discharge when it is determined that the deterioration diagnosis of the battery is impossible.