Abstract: A negative electrode active material composite particle according to one embodiment is a composite particle for a negative electrode active material, the composite particle including: a lithium silicate phase; silicon particles dispersed in the lithium silicate phase; and a resin-calcined material. The resin-calcined material containing at least one element selected from F and N. The composite particle has a porosity of 10% or less, for example, and the content of the resin-calcined material is 1-20% by mass with respect to the mass of the composite particle.

Abstract: A non-aqueous electrolyte secondary battery according to an aspect of the present disclosure comprises: an electrode body obtained by winding a positive electrode and a negative electrode with a separator therebetween; an electrolytic solution; and an exterior body that houses the electrode body and the electrolytic solution. The negative electrode has: a negative electrode current collector; and a negative electrode mixture layer formed on the surface of the negative electrode current collector, wherein the negative electrode mixture layer contains a negative electrode active material and fibrous carbon, and the average fiber length of the fibrous carbon contained in the central part of the negative electrode mixture layer in the width direction is greater than the average fiber length of the fibrous carbon contained in both end parts of the negative electrode mixture layer in the width direction.

Abstract: A nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure is provided with a wound-type electrode body. A negative electrode has: a negative electrode collector; and negative electrode mixture layers that are formed on both lateral surfaces of the negative electrode collector, while containing at least a negative electrode active material and a binder. The negative electrode mixture layers include an inner negative electrode mixture layer that is positioned on the inner circumference side of the negative electrode collector and an outer negative electrode mixture layer that is positioned on the outer circumference side. The swelling degree of the binder contained in the outer negative electrode mixture layer is higher than the swelling degree of the binder contained in the inner negative electrode mixture layer; and the outer negative electrode mixture layer contains a binder that has a swelling degree of from 150% to 250%.

Abstract: A secondary cell that is one example of this embodiment comprises a winding-type electrode body in which a positive electrode and a negative electrode are wound with a separator interposed therebetween. The positive electrode has: a positive-electrode collector body; a first positive-electrode mixture layer formed on a first surface of the positive-electrode collector body facing the outer side of the electrode body; and a second positive-electrode mixture layer formed on a second surface of the positive-electrode collector body facing the inner side of the electrode body. The first positive-electrode mixture layer includes a first positive-electrode active material, and the second positive-electrode mixture layer includes a second positive-electrode active material, the average surface roughness of the first positive-electrode active material being greater than the average surface roughness of the second positive-electrode active material.

Abstract: The purpose of the present invention is to provide a winding-type nonaqueous electrolyte secondary battery which is capable of minimizing degradation of charge-discharge cycle characteristics.