DEFORMATION-DETECTING SENSOR FOR SEALED SECONDARY BATTERY

A deformation detecting sensor for a sealed secondary battery of the present invention is used with a unit cell, battery module, or battery pack of the sealed secondary battery and includes: a magnetic resin layer stuck to the unit cell and/or battery module, the resin layer comprising a matrix composed of a resin component and a magnetic filler dispersed in the matrix; and a magnetic sensor attached to the inside or outside wall of a package case so as to be capable to detect a change of a magnetic field caused by the magnetic layer. The present invention can provide a deformation detecting sensor capable to detect bulging of a sealed secondary battery with higher sensitivity and to exhibit stable detection characteristics.