Cylindrical nonaqueous electrolyte secondary battery
A nonaqueous electrolyte secondary battery according to an embodiment of the present disclosure includes: a wound electrode assembly ( 14 ) formed by spirally winding, via a separator ( 13 ), a positive electrode ( 11 ) and a negative electrode ( 12 ) in which a negative electrode mixture layer is formed on a negative electrode core, where: the negative electrode ( 12 ) includes a non-opposing portion ( 12 a ) that is wound 1.25 turns or more from an inner edge in a winding direction of the wound electrode assembly ( 14 ) without facing the positive electrode via the separator ( 13 ); the non-opposing portion ( 12 a ) includes a negative electrode mixture layer-formed portion ( 12 c ) in which the negative electrode mixture layer is formed on at least either side continuously in an inward winding direction from an outer edge in the winding direction; and the negative electrode mixture layer-formed portion ( 12 c ) is wound 0.75 turns or more.
1. A cylindrical nonaqueous electrolyte secondary battery comprising:
a wound electrode assembly formed by spirally winding, via a separator, a positive electrode and a negative electrode in which a negative electrode mixture layer is formed on a negative electrode core;
a nonaqueous electrolyte; and
a package that houses the wound electrode assembly and the nonaqueous electrolyte, wherein:
the negative electrode includes a non-opposing portion that is wound 1.25 turns or more from an inner edge in a winding direction of the wound electrode assembly without facing the positive electrode via the separator;
the non-opposing portion includes a negative electrode mixture layer-formed portion in which the negative electrode mixture layer is formed on at least either side continuously in an inward winding direction from an outer edge of the non-opposing portion in the winding direction, and a negative electrode core-exposed portion in which the negative electrode mixture layer is not formed on either side continuously in an outward winding direction from the inner edge of the non-opposing portion in the winding direction;
the negative electrode mixture layer-formed portion is wound 0.75 turns or more, and
a length in the winding direction of the negative electrode core-exposed portion, denoted as a, and a length in the winding direction of the negative electrode mixture layer-formed portion, denoted as b, satisfy 1≤(b/a).
2. The cylindrical nonaqueous electrolyte secondary battery according to claim 1 , wherein:
a negative electrode lead is connected to the negative electrode core-exposed portion.
3. The cylindrical nonaqueous electrolyte secondary battery according to claim 1 , wherein
the negative electrode mixture layer contains silicon oxide represented by SiO x (0.5≤x≤1.6).
4. The cylindrical nonaqueous electrolyte secondary battery according to claim 2 , wherein
the negative electrode mixture layer contains silicon oxide represented by SiO x (0.5≤x≤1.6).