SECONDARY BATTERY

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Inventor(s)

SECONDARY BATTERY

This abstract first appeared for US patent application 18944748 titled 'SECONDARY BATTERY

Original Abstract Submitted

A secondary battery having higher reliability is provided. The secondary battery includes a battery device and an outer package member. The battery device includes a first electrode and a second electrode that are stacked with a separator interposed between the first electrode and the second electrode, and are wound around a winding axis extending in a first direction. The outer package member contains the battery device. The second electrode includes a second electrode current collector, an inner side second electrode active material layer, and an outer side second electrode active material layer. The second electrode current collector has an inward second electrode surface and an outward second electrode surface. The inward second electrode surface faces a side of the winding axis. The outward second electrode surface is on an opposite side to the inward second electrode surface. The inner side second electrode active material layer is provided on the inward second electrode surface. The outer side second electrode active material layer is provided on the outward second electrode surface. An area density of the outer side second electrode active material layer is higher than an area density of the inner side second electrode active material layer over a region from an inner winding side end part of the battery device to an outer winding side end part of the battery device. The inner side second electrode active material layer is opposed to the outer side second electrode active material layer with the second electrode current collector interposed between the inner side second electrode active material layer and the outer side second electrode active material layer.