A method of manufacturing a battery including a wound electrode assembly in which a first separator, a negative electrode plate, a second separator, and a positive electrode plate are wound together is disclosed. The method includes step (A) of suction-attaching the first separator to a winding core, and step (B) of winding the first separator on the winding core. The winding core includes a plurality of suction holes for suction-attaching the first separator. When the outer circumference of the winding core is divided into four equal parts and the four equal parts are defined respectively as first to fourth regions starting from a position that faces a starting end of winding of the first separator, greater than or equal to 80%, by aperture area ratio, of the suction holes are formed in the first region.

A method of manufacturing a battery including a wound electrode assembly in which a first separator, a negative electrode plate, a second separator, and a positive electrode plate are wound together is disclosed. The method includes step (A) of suction-attaching the first separator to a winding core, and step (B) of winding the first separator on the winding core. The winding core includes a plurality of suction holes for suction-attaching the first separator. When the outer circumference of the winding core is divided into four equal parts and the four equal parts are defined respectively as first to fourth regions starting from a position that faces a starting end of winding of the first separator, greater than or equal to 80%, by aperture area ratio, of the suction holes are formed in the first region.

An electrode sheet includes a current collector and a first active material layer on a first surface of the current collector. The first active material layer includes a main portion and a first buffer portion. The main portion includes a first inner surface and an outer surface. The first inner surface is attached to the current collector, and the outer surface is parallel to the first inner surface. The first active material layer has a height that is a vertical distance from the outer surface to the first inner surface. The first buffer portion includes a second inner surface, a buffer surface, and an inner wall surface defining a first groove. A first end of the buffer surface is connected to the outer surface, a second end of the buffer surface is connected to the inner wall surface. The inner wall surface is shorter than the first active material layer.

An electrode sheet includes a current collector and a first active material layer on a first surface of the current collector. The first active material layer includes a main portion and a first buffer portion. The main portion includes a first inner surface and an outer surface. The first inner surface is attached to the current collector, and the outer surface is parallel to the first inner surface. The first active material layer has a height that is a vertical distance from the outer surface to the first inner surface. The first buffer portion includes a second inner surface, a buffer surface, and an inner wall surface defining a first groove. A first end of the buffer surface is connected to the outer surface, a second end of the buffer surface is connected to the inner wall surface. The inner wall surface is shorter than the first active material layer.

An electrode assembly having a positive electrode; a negative electrode; and a separator interposed between the positive electrode and the negative electrode is provided. The positive electrode includes a positive electrode active material layer located on a positive electrode current collector, and the negative electrode includes a negative electrode active material layer located on a negative electrode current collector. A non-coated part is located at an edge of the negative electrode current collector. A disconnection preventing layer is located at the negative electrode current collector. The disconnection preventing layer extends from an external side of the non-coated part and is bent to overlap a portion of the non-coated part.

An electrode assembly having a positive electrode; a negative electrode; and a separator interposed between the positive electrode and the negative electrode is provided. The positive electrode includes a positive electrode active material layer located on a positive electrode current collector, and the negative electrode includes a negative electrode active material layer located on a negative electrode current collector. A non-coated part is located at an edge of the negative electrode current collector. A disconnection preventing layer is located at the negative electrode current collector. The disconnection preventing layer extends from an external side of the non-coated part and is bent to overlap a portion of the non-coated part.

(A): Winding a first separator, a second separator, a positive electrode plate, and a negative electrode plate onto a winding core disposed at a first position. (B): Moving the winding core away from the first position and disposing another winding core at the first position. (C): Cutting the first separator and the second separator wound on the winding core that is moved away from the first position in (B) at a location on or near the other winding core disposed at the first position in (B), with the first separator and the second separator being stacked and retained on an outer circumferential surface of the other winding core. (D): Winding the first separator and the second separator onto the winding core that is moved away from the first position in (B) up to a cut edge portion at which the first separator and the second separator are cut in (C).

(A): Winding a first separator, a second separator, a positive electrode plate, and a negative electrode plate onto a winding core disposed at a first position. (B): Moving the winding core away from the first position and disposing another winding core at the first position. (C): Cutting the first separator and the second separator wound on the winding core that is moved away from the first position in (B) at a location on or near the other winding core disposed at the first position in (B), with the first separator and the second separator being stacked and retained on an outer circumferential surface of the other winding core. (D): Winding the first separator and the second separator onto the winding core that is moved away from the first position in (B) up to a cut edge portion at which the first separator and the second separator are cut in (C).

A disclosed method of manufacturing a battery includes the steps of: (A) suction-attaching a first separator and a second separator to a winding core, with the first separator and the second separator being stacked on each other; and (B) winding the first separator and the separator around the winding core. Each of the first separator and the second separator includes a porous substrate layer made of resin, and at least one surface layer formed on at least one surface of the substrate layer.

A disclosed method is a method of manufacturing a battery including a wound electrode assembly in which a first separator, a negative electrode plate, a second separator, and a positive electrode plate are wound together. The method includes steps of winding the first separator, the negative electrode plate, the second separator, and the positive electrode plate onto a winding core, to prepare a wound electrode assembly, and removing the wound electrode assembly from the winding core. The winding core includes a first component and a second component. In the step of removing the wound electrode assembly from the winding core, at least one of the first component and the second component moves in a direction in which a distance between the first component and the second component decrease so that a diameter of the winding core decreases. Thereafter, the wound electrode assembly is removed from the winding core.