The invention relates to an activation device for an electric battery unit, in particular, for a battery part of a torpedo. The invention also relates to a battery unit with activation devices of this type.An activation device incorporates an operating supply connection, to which an operating supply reservoir can be connected. A movably arranged cutting element can be pneumatically actuated via a pneumatic connection of the activation device by means of an actuation element, wherein a sealing element arranged in the path of travel of the cutting element controls the operating supply connection.In order to guarantee a safe storage, ready for operation, and a safe activation of a battery unit, it is provided in accordance with the invention that the activation device incorporates a pneumatic outlet, which can be fluidically connected to the pneumatic connection, depending on the position of the actuation element.