The present invention relates to a battery package attached to an external substrate, which includes an electronic circuit and a power terminal electrically connected to the electronic circuit, to supply power to the electronic circuit, or to accumulate energy by collecting power. A battery package, according to an exemplary embodiment, comprises: a battery unit that has one or more secondary battery cells and leads that are connected to the secondary battery cells and exposed; a flexible encapsulation body that accommodates the battery unit therein; exposed electrodes that are exposed on the surface of the flexible encapsulation body and are electrically connected to the leads to electrically connect to the electronic circuit; and a first Velcro part mounted on the surface of the flexible encapsulation body.