Abstract: An electrode in sheet form includes a current collector and an electrode mixture layer carried on each side thereof. The electrode is bent in the longitudinal direction thereof, to cause a large number of cracks in at least the electrode mixture layer to be positioned on the inner side of the current collector when wound, such that the cracks extend from the surface of the electrode mixture layer to the current collector in the direction intersecting with the longitudinal direction of the electrode. This bending process includes the steps of: bending the electrode at a curvature that is smaller than that of the winding core at least once; and thereafter bending the electrode at a curvature that is equal to or larger than that of the winding core. For example, this process is performed by arranging rollers such that their diameters decrease gradually and pressing the electrode against these rollers. This invention provides an electrode that does not break when wound to form an electrode assembly.

Abstract: An electrode in sheet form includes a current collector and an electrode mixture layer carried on each side thereof. The electrode is bent in the longitudinal direction thereof, to cause a large number of cracks in at least the electrode mixture layer to be positioned on the inner side of the current collector when wound, such that the cracks extend from the surface of the electrode mixture layer to the current collector in the direction intersecting with the longitudinal direction of the electrode. This bending process includes the steps of: bending the electrode at a curvature that is smaller than that of the winding core at least once; and thereafter bending the electrode at a curvature that is equal to or larger than that of the winding core. For example, this process is performed by arranging rollers such that their diameters decrease gradually and pressing the electrode against these rollers. This invention provides an electrode that does not break when wound to form an electrode assembly.

Abstract: An electrode in sheet form includes a current collector and an electrode mixture layer carried on each side thereof. The electrode is bent in the longitudinal direction thereof, to cause a large number of cracks in at least the electrode mixture layer to be positioned on the inner side of the current collector when wound, such that the cracks extend from the surface of the electrode mixture layer to the current collector in the direction intersecting with the longitudinal direction of the electrode. This bending process includes the steps of: bending the electrode at a curvature that is smaller than that of the winding core at least once; and thereafter bending the electrode at a curvature that is equal to or larger than that of the winding core. For example, this process is performed by arranging rollers such that their diameters decrease gradually and pressing the electrode against these rollers. This invention provides an electrode that does not break when wound to form an electrode assembly.

Abstract: To present a processing apparatus capable of forming an annular support portion for mounting a sealing plate on an elliptical battery case can at high precision and high productivity, and a structure of an elliptical battery using an elliptical battery case can.An elliptical battery case can 10 is rotatably held by a case can support mechanism 13. The battery case can 10 is rotated about its tubular center by a case can rotary mechanism 18. Two groove forming rollers 23, 24 are mounted on an oscillatable roller support lever 28. The roller support lever 28 traces the shape of the outer circumference of the battery case can 10, and oscillates within a plane orthogonal to the tubular center of the battery case can 10, and receives a pressing force from a pressurizing device 29 to press the both groove forming rollers 23, 24 against the outer circumference of the battery case can 10.