A method for encapsulating a device, such as an battery, having two opposite and parallel main faces and a peripheral edge, wherein one main face includes an electrical contact zone, includes the steps of retaining the device within an injection chamber of a mold and injecting encapsulation material into the injection chamber to overmold an encapsulation block on the device. The injection chamber is configured to hold a portion of the device, adjacent its peripheral edge, so as to center the device within the injection chamber. The mold includes centering structures that at least partially cover the electrical contact zone. Opposite positioning studs protrude into the injection chamber and bear on the opposite main faces of the device. The resulting packaged device includes an overmolded encapsulation block enveloping the device except for portions covered by the centering structure.