Solid-state lithium ion battery and preparation method thereof

The invention discloses a solid-state lithium ion battery and a preparation method thereof, the battery comprises a composite positive plate and a negative plate, and the composite positive plate comprises a positive current collector; the positive active material layer is arranged on the surface of the positive current collector, and the width and the thickness of the positive active material layer are D1 and L1 respectively; the solid electrolyte layer is arranged on the surface of the positive electrode active material layer, the width of the solid electrolyte layer is D2, the thickness of the solid electrolyte layer is L2, and D2 ([mu] m) = D1 ([mu] m) + 25,000/L2 ([mu] m), and L2 is larger than or equal to 10 [mu] m and smaller than or equal to 100 [mu] m. According to the solid-state lithium ion battery, internal short circuit caused by contact of the positive electrode and the negative electrode can be effectively avoided, particularly, the solid-state electrolyte layer with certain ductility is suitab