NEGATIVE ELECTRODE AND LITHIUM ION SECONDARY BATTERY

摘要

PURPOSE: A negative electrode is provided to suppress the separation of a negative active material layer from a negative current collector, to keep current collection in a high level, and to produce a lithium ion secondary battery with excellent rechargeable cycle characteristic and output characteristic. CONSTITUTION: A negative electrode(12) comprises a negative electrode current collector and a negative active material layer. The negative electrode current collector includes a sheet-like substrate part and plural concave parts(21). The concave parts protrudes from the surface of at least one side of the substrate part to the outside. The negative active material layer comprises a column-shape active material layer(25) and a laminated active material layer(26).