NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY
The non-aqueous electrolyte secondary battery according to one embodiment of the present disclosure comprises a wound-type electrode body. A negative electrode has: a negative electrode current collector; a double-sided coated part in which a negative electrode mixture layer including a negative electrode active material and a binder is formed on the surface of the negative electrode current collector, and a negative electrode mixture layer is formed on both surfaces of the negative electrode current collector; and a one-sided coated part in which a negative electrode mixture layer is formed on one outer-periphery-side surface of the negative electrode current collector. At least a portion of the one-sided coated part is positioned on the outermost periphery of the electrode body. The swelling degree of the binder in the one-sided coated part is higher than the swelling degree of the binder in the double-sided coated part.
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 can that houses the electrode assembly, wherein
the positive electrode has a positive electrode mixture layer formed on a surface of a sheet-shaped positive electrode current collector,
the negative electrode has a negative electrode mixture layer formed on a surface of a sheet-shaped negative electrode current collector,
the negative electrode mixture layer includes a rechargeable active material and a binder,
the negative electrode has a both-surface coated portion in which the negative electrode mixture layer is formed on both surfaces of the negative electrode current collector, and a one-surface coated portion in which the negative electrode mixture layer is formed on one surface of the negative electrode current collector,
at least a part of the one-surface coated portion is disposed on an outermost circumference of the electrode assembly,
at least a part of an exposed surface of the negative electrode current collector in the one-surface coated portion is contacted with an inner face of the exterior housing can, and
a degree of swelling of the binder by an electrolyte liquid in the one-surface coated portion is larger than a degree of swelling of the binder in the both-surface coated portion.
2 . The non-aqueous electrolyte secondary battery according to claim 1 , wherein the degree of swelling of the binder in the one-surface coated portion is 1.2 to 2.1 times larger than the degree of swelling of the binder in the both-surface coated portion.
3 . The non-aqueous electrolyte secondary battery according to claim 1 , wherein the binder is a styrene-butadiene rubber.
4 . The non-aqueous electrolyte secondary battery according to claim 1 , wherein the negative electrode mixture layer includes a silicon material.