All-solid state secondary battery and method of manufacturing the same

A method of manufacturing an all-solid state secondary battery including a laminate in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated in this order, the method comprising:

• setting respective areas of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer such that [the area of the positive electrode layer]<[the area of the negative electrode layer]≤[the area of the solid electrolyte layer] is satisfied;
• disposing a buffer layer having an area more than the area of the solid electrolyte layer and having a Young's modulus lower than that of each of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer on both of a side of the positive electrode layer opposite to the solid electrolyte layer side and a side of the negative electrode layer opposite to the solid electrolyte layer side;
• and
• pressurizing the laminate through the buffer layer;
• wherein the pressurized state is a state the laminate is pressurized by a pressurizing plate,
• wherein a nonconductor layer is provided on an outer peripheral portion of the positive electrode layer,
• wherein the thickness of the buffer layer is more than a total thickness of the positive electrode layer, the solid electrolyte layer, and the negative electrode layer, and the Young's modulus of the buffer layer is 0.01 GPa or higher and lower than 2 GPa.