Thin battery and a battery device

Exterior electrode group and the storage electrode group comprises a thin sheet-like battery of the present invention, the electrode assembly having a positive electrode, a negative electrode, and an electrolyte layer interposed between the positive electrode and the negative electrode, the lubricating material having lubricating effect between the outer casing between the surface of the electrode group, for example, the lubricating substance is an inert gas. Inert gas such as nitrogen and argon containing at least one of. Lubricating substance is preferably present at least in the thickness direction of the end face of the electrode group with the facing end sides of the main flat surface between the inner surface of the exterior body facing.