To make the sealing perfect and facilitate the mounting by packaging a battery element consisting of a positive electrode and negative electrode layered through a solid electrolyte and contained in a facing with a synthetic resin film.
It is preferred to perfectly package at least four surfaces of a battery element excluding the surface where a terminal part is present with a synthetic resin film, so that the contamination of a sealed part by an electrolyte and the slippage of the battery element in use can be efficiently prevented, and the battery can be smoothly inserted to a bag-like facing material. It is preferred to set the thickness of the battery element to 0.3-30 mm and the thickness of the synthetic resin film to 2-100 μm from the viewpoint of ensuring of energy density and strength. In order to attain the perfect packaging and ensure the energy density, the length of the synthetic resin film is preferably set, according to its thickness, to a prescribed times the peripheral length of the battery element. As the synthetic resin film, polyethylene, polypropylene, fluorine resin, polyester or polyimide is preferably used, so that the swelling rate to the solid electrolyte is 20% or less.
KATO IKUO
YANAI MASAHIRO
FUJII TOSHISHIGE
