Slim type Li-polymer portable battery. This product charges mobile devices including smartphones and tablets through USB. It is usable for a long period as is rechargeable through AC / USB. It maintains an easy to use interface, e.g. even in a situation of using it in a bag. Simple design is adopted with tough and recyclable material. Supporting various charging styles in such scenes as everyday life, business travels, outdoor leisure, and emergency situations including disaster and blackout.