A method for depassivation of a lithium-thionyl battery includes applying at least one current test load (LAST) (101) to an electrode of the battery (10), wherein at least one of a shape, a magnitude or points in time of the application of the at least one current test load (LAST) occurs dependent on a measurement of a response signal (u(t), du(t) on the battery (10), and energy of the at least one current test load (LAST) is drawn from the battery (10), comparing the response signal (u(t), du(t) of the battery (10) arising from application of the at least one current test load (LAST) to at least one predefined criterion (103), and establishing an operating state (12) or issuing an error message depending on satisfaction of the at least one predefined criterion (103).