Nonaqueous electrolyte secondary battery provided with a wound electrode body

Abstract

A main object of the present invention to provide a nonaqueous electrolyte secondary battery having high durability towards charge and discharge cycles, by preventing buckling of a wound electrode body. The secondary battery provided by the present invention comprises: a nonaqueous electrolyte; and a wound electrode body 80 configured by superposing on each other, and winding a positive electrode sheet 10 having a positive electrode collector formed to a sheet shape and a positive electrode active material layer formed on that collector, a, negative electrode sheet 20 having a negative electrode collector formed to a sheet shape and a negative electrode active material layer formed on that collector, and a separator 40 formed to a sheet shape. The negative electrode active material contained in the negative electrode active material layer is oriented in a predetermined direction. The positive electrode sheet 10, negative electrode sheet 20 and separator sheet 40 all have a tensile elongation at break of 2% or higher.

Dependencies are inferred from the claim text.