Abstract: In a lithium ion secondary battery which is composed of a positive electrode 1, a negative electrode 4 and a separator 7 which contains a Li ion-containing non-aqueous electrolytic solution, both of the ionic conductivity and adhesion strength were ensured by making an adhesive resin layer 8 which bonds the positive electrode 1 to the separator 7 and the negative electrode 4 to the separator 7 into a mixture phase consisting of an electrolytic solution phase 9, an electrolytic solution-containing a polymer gel phase 10 and a polymer solid phase 11.

Abstract: To provide a process for producing a lithium ion secondary battery which can have any arbitrary shape, such as thin shape, and yet exhibits high performance. In a method of fabricating a battery comprising a positive electrode 1, a negative electrode 4, and a separator 7, a binder resin solution mainly comprising polyvinylidene fluoride is applied to the separator 7, and the positive electrode 1 and the negative electrode 4 are laid thereon, followed by drying to form a battery laminate, which is then impregnated with an electrolytic solution.

Abstract: To obtain a lithium ion secondary battery having excellent charge and discharge characteristics in which electric connection between active material layers and a separator can be maintained without requiring a strong armor metal case, so that it can be made into thin forms having large energy density. Convex parts and concave parts are formed on at least two surfaces among surfaces of a positive electrode active material layer 7 and a negative electrode active material layer 9 both adjacent to a separator 4 and surfaces of the separator 4 facing both of the active material layers 7, 9, and these three means are bonded and closely adhered by an adhesive resin layer 11 and electrically connected by keeping a lithium ion-containing electrolytic solution in the separator 4 and voids 12 formed by a bonded surface 11a of the convex parts and the concave parts.