Non-aqueous electrolyte secondary battery and method of producing the same
A non-aqueous electrolyte secondary battery includes at least an electrode composite material layer, an intermediate layer, and an electrode current collector. Intermediate layer is interposed between electrode composite material layer and electrode current collector. Intermediate layer contains at least insulating particles and conductive particles. Each insulating particle has an arc shape in a cross section of intermediate layer along a thickness direction. More conductive particles are present on an outer-circumference side of each arc shape than on an inner-circumference side of the arc shape.
1. A method of producing a non-aqueous electrolyte secondary battery, the method comprising at least:
forming an intermediate layer on a surface of an electrode current collector;
forming an electrode composite material layer on a surface of the intermediate layer; and
compressing the intermediate layer,
the intermediate layer being formed so as to contain at least hollow ceramic particles and conductive particles, the conductive particles being at least one of:
acetylene black particles,
graphite particles,
graphene particles,
vapor grown carbon fiber, or
carbon nanotubes,
compression of the intermediate layer causing breakage of the hollow ceramic particles to form ceramic particles having an arc shape,
within a cross section of the intermediate layer along a thickness direction, each ceramic particle has an arc shape.
2. A non-aqueous electrolyte secondary battery comprising at least:
an electrode composite material layer;
an intermediate layer; and
an electrode current collector,
the intermediate layer being interposed between the electrode composite material layer and the electrode current collector,
the intermediate layer containing at least ceramic particles and conductive particles, the conductive particles being at least one of:
acetylene black particles,
graphite particles,
graphene particles,
vapor grown carbon fiber, or
carbon nanotubes,
within a cross section of the intermediate layer along a thickness direction,
each ceramic particle having an arc shape, and
more conductive particles being present on an outer-circumference side of each arc shape than on an inner-circumference side of the arc shape; wherein the non-aqueous electrolyte secondary battery is prepared by the method of claim 1 .
3. The non-aqueous electrolyte secondary battery according to claim 2 , wherein
the arc shape comprises an outer-circumference line and an inner-circumference line,
a region with a width of 1 μm extending from the outer-circumference line in a direction away from the inner-circumference line is defined as an outer-circumference region, a region with a width of 1 μm extending from the inner-circumference line in a direction away from the outer-circumference line is defined as an inner-circumference region,
the conductive particles have a first concentration in the outer-circumference region, the conductive particles have a second concentration in the inner-circumference region, and
a ratio of the first concentration to the second concentration is higher than 1.
4. The non-aqueous electrolyte secondary battery according to claim 3 , wherein
the ratio of the first concentration to the second concentration is not lower than 2 and not higher than 50.
5. The non-aqueous electrolyte secondary battery according to claim 3 , wherein
the outer-circumference line has a first radius of curvature, the inner-circumference line has a second radius of curvature, and
a ratio of the second radius of curvature to the first radius of curvature is not lower than 0.3 and not higher than 0.95.
6. The non-aqueous electrolyte secondary battery according to claim 2 , wherein
the intermediate layer has a porosity not lower than 5% and not higher than 30%.
7. The non-aqueous electrolyte secondary battery according to claim 2 , wherein
the intermediate layer contains the conductive particles in an amount not lower than 0.01 mass % and not higher than 5 mass %.