Non-aqueous electrolyte secondary battery and method for producing non-aqueous electrolyte secondary battery
The non-aqueous electrolyte secondary battery according to an aspect of the present disclosure comprises: a wound electrode body on which a strip-like positive electrode and a strip-like negative electrode are each wound with a separator interposed therebetween; and an outer package accommodating the electrode body. The positive electrode comprises a positive current collector and a positive mixture layer that is formed on the positive current collector and contains at least a positive active material and a binder. The negative electrode comprises a negative current collector and a negative mixture layer that is formed on the negative current collector and contains at least a negative active material and a binder. At least one of the positive mixture layer and the negative mixture layer has a binder content that is higher on a leading end than on a terminal end.
1 . A non-aqueous electrolyte secondary battery, comprising:
a wound electrode assembly in which a band-shaped positive electrode and a band-shaped negative electrode are wound with a separator interposed therebetween; and
an exterior housing body that houses the electrode assembly, wherein
the positive electrode has: a positive electrode current collector; and a positive electrode mixture layer formed on the positive electrode current collector and including at least a positive electrode active material and a binder;
the negative electrode has: a negative electrode current collector; and a negative electrode mixture layer formed on the negative electrode current collector and including at least a negative electrode active material and a binder; and
in a longitudinal direction of at least one of the band-shaped positive and negative electrodes, at least one of the positive electrode mixture layer and the negative electrode mixture layer has a higher content rate of the binder in an initial end part than a content rate of the binder in a terminal end part provided on a same side of the current collector, wherein the initial end part corresponds to a winding core end of the band-shaped electrode, the terminal end part corresponds to a winding outer end of the band-shaped electrode.
2 . The non-aqueous electrolyte secondary battery according to claim 1 , wherein at least one of the positive electrode mixture layer and the negative electrode mixture layer has a region where a content rate of the binder continuously decreases from the initial end part side to the terminal end part side.
3 . The non-aqueous electrolyte secondary battery according to claim 1 , wherein a winding radius of an innermost circumference of the negative electrode in the electrode assembly is 1 mm to 5 mm.
4 . The non-aqueous electrolyte secondary battery according to claim 1 , wherein a region where the content rate of the binder continuously decreases from an initial end part side to a terminal end part side is provided in at least a part of the negative mixture layer.