Abstract: A method of propagation test on a battery system has: a main irradiation step of irradiating a laser beam in prescribed conditions, on a light-receiving part of the outer member of a light-receiving cell, or on a light-receiving part which is arranged in contact with the outer member of the light-receiving cell, thereby to heat the light-receiving cell; a thermal runaway confirming step of confirming a thermal runaway of the light-receiving cell; an irradiation stopping step of stopping the laser-beam irradiation after the thermal runaway was confirmed in the thermal runaway confirming step; and a system integrity inspection step of inspecting an integrity of the cells other than the light-receiving cell after the irradiation stopping step. The prescribed conditions are conditions in which a melted scar is formed on the light-receiving part.

Abstract: A method of propagation test on a battery system has: a main irradiation step of irradiating a laser beam in prescribed conditions, on a light-receiving part of the outer member of a light-receiving cell, or on a light-receiving part which is arranged in contact with the outer member of the light-receiving cell, thereby to heat the light-receiving cell; a thermal runaway confirming step of confirming a thermal runaway of the light-receiving cell; an irradiation stopping step of stopping the laser-beam irradiation after the thermal runaway was confirmed in the thermal runaway confirming step; and a system integrity inspection step of inspecting an integrity of the cells other than the light-receiving cell after the irradiation stopping step. The prescribed conditions are conditions in which a melted scar is formed on the light-receiving part.