NOVELTY - A battery (1) manufacturing method involves forming first active material layer (12) on surface of base material, and having unevenness on a surface opposite to a surface in contact with base material; forming a solid electrolyte layer (13) having unevenness of first active material layer on surface opposite to a surface in contact with first active material layer; forming second active material layer; and heating solid electrolyte layer to reduce viscosity of solid electrolyte layer after forming second active material layer.    USE - As battery manufacturing method, used as power source in vehicles and electronic device (claimed).    ADVANTAGE - The lithium-ion secondary battery module has a structure which is thin and flexible. Since the negative-electrode active material layer is formed to have an uneven space structure, thus increases surface area with respect to its volume, an area facing the positive-electrode active material layer via the thin solid electrolyte layer can be increased to ensure high efficiency and high output. The method is suitable for manufacturing a battery using a solid electrolyte and having a small size, has high performance and with excellent productivity.    DETAILED DESCRIPTION - A battery (1) manufacturing method involves forming first active material layer (12) on surface of base material by applying first application liquid containing first active material on surface of base material, where the first active material layer has unevenness on surface opposite to surface in contact with base material; forming solid electrolyte layer (13) by applying second application liquid containing solid electrolyte material on surface of first active material layer and increasing viscosity of second application liquid, where electrolyte layer has unevenness in conformity with unevenness of first active material layer on surface opposite to surface in contact with first active material layer; forming a second active material layer by applying third application liquid containing second active material on surface of solid electrolyte layer; and heating the solid electrolyte layer to reduce the viscosity of solid electrolyte layer after second active material layer forming step. INDEPENDENT CLAIMS are included for the following:    (1) battery with a structure in which first current collector layer, first active material layer, solid electrolyte layer, second active material layer and second current collector layer are laminated in this order, where the first active material layer, the solid electrolyte layer and the second active material layer are formed using the first current collector layer as the base material by the manufacturing method;    (2) vehicle comprising a motor and the battery for supplying power to the motor; and    (3) electronic device comprising the battery, and a circuit unit which operates using the battery as a power supply.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of battery.    Lithium-ion secondary battery (1)    Negative-electrode active material (12)    Solid electrolyte (13)    Positive-electrode current collector (14)    Positive-electrode current collector (15)