METHOD FOR MANUFACTURING BATTERY CELL

A manufacturing method to prevent insufficient welding of resin pieces during manufacture of a battery cell includes stacking electrode sheets in a layering direction, the electrode sheets each including an electrode and a current collector. The electrodes are located in a container, and the current collectors are each connected to the electrode in the container and protrude outward from an opening of the container. The method also includes preheating resin pieces, located between adjacently stacked current collectors, through the current collectors. After preheating is started, pressurizing and heating the resin pieces is started from an outside toward a center in the layering direction at a position of the opening of the container. Resin pieces are welded together between the current collectors, and the opening of the container is sealed.