Method for manufacturing battery

A method for manufacturing a battery, the method comprising conveying a heated elongated sheet-shaped bipolar electrode laminate by a conveyor roller, wherein

• the bipolar electrode laminate includes a first electrode active material layer, a current collector layer, and a second electrode active material layer in this order,
• the first electrode active material layer includes a plurality of island portions extending in a conveying direction with at least one gap portion extending in the conveying direction between the island portions,
• a temperature decrease of the bipolar electrode laminate when the bipolar electrode laminate passes over the conveyor roller is 30° C. or more, and
• the conveyor roller includes a projecting portion or a gas discharge portion positioned to overlap the gap portion or a surface opposite to the gap portion such that a transverse stretching stress is applied to the gap portion during roller conveying for the bipolar electrode laminate by the conveyor roller.