ABNORMALITY DETECTION SYSTEM

An abnormality detection system includes a removable battery and a server. The removable battery has: a detector; a battery side acquisition unit for acquiring measured data that are the data of measured values measured by the detector and acquiring, from an object to be electrically driven, first recognition data for recognizing the object to be electrically driven; and a battery side storage unit. The server has: a server side storage unit for prestoring reference data that are the data acquired when the object to be electrically driven performs a predetermined operation; a server side acquisition unit for acquiring the measured data, the first recognition data, and second recognition data; and an abnormality detection unit for comparing actual work data obtained from the measured data with the reference data and detecting an abnormality when the difference between the actual work data and the reference data exceeds a threshold value.