BATTERY SYSTEM AND METHOD FOR DETERMINING ABNORMALITY OF BATTERY

A battery system, capable of detecting a pore generated in an outer package film in an early stage, includes: a battery including a plurality of laminated cells arranged along a thickness direction and connected in series, and a plate arranged between a pair of the laminated cells; a first voltage sensor configured to measure a first voltage between a terminal of a reference cell belonging to the plurality of laminated cells, and the plate; a second voltage sensor configured to measure a second voltage between a terminal of the reference cell, and among the pair of laminated cells facing the plate, the laminated cell in the reference cell side; and an electronic control unit including a first obtaining unit configured to obtain the first voltage from the first voltage sensor.