CURRENT COLLECTOR FOR SECONDARY BATTERY AND SECONDARY BATTERY

To provide a current collector, as a current collector for use in a secondary battery, light in weight, less in performance deterioration and long in lifetime, and a secondary battery in which the current collector is used.SOLUTION: A current collector for a secondary battery includes a resin film 1A, a first metal film 1B arranged in contact with a first surface of the resin film 1A, and a second metal film 1C arranged in contact with a second surface of the resin film 1A. The resin film 1A contains an acid-modified polyolefin and has evaluation indexes satisfying predetermined conditions. The acid-modified polyolefin is a material excellent in adhesiveness with metal, and the acid-modified polyolefin and the metal are firmly bonded without an intermediate layer interposed therebetween, so that the current collector is reduced in thickness and lightened in weight. The first metal film and the second metal film are arranged on both surfaces of the resin film, so that the symmetry of a structure in a thickness direction is increased to relieve stress. Specifically, when the evaluation indexes satisfy specific conditions, not only adhesiveness, but also electrolyte resistance can be increased.SELECTED DRAWING: Figure 2 【課題】 二次電池に用いられる集電体として、軽量、且つ、性能劣化が少なく長寿命な集電体と、当該集電体を用いた二次電池が期待されている。【解決手段】二次電池用の集電体は、樹脂膜１Ａと、樹脂膜１Ａの第１面上に接して配置された第１金属膜１Ｂと、樹脂膜１Ａの第２面上に接して配置された第２金属膜１Ｃとを備え、樹脂膜１Ａは、酸変性ポリオレフィンを含み、且つ、評価指標が所定条件を満たしている。酸変性ポリオレフィンは、金属との接着性に優れる材料であり、中間層を介在させることなく、これらが強固に接着され、薄く、軽量なものとなる。樹脂膜の両面上には第１金属膜及び第２金属膜が配置されており、厚み方向の構造の対称性が増加し、応力を緩和している。特に、評価指標が特定の条件を満たす場合、接着性のみならず、電解液耐性も高くなる。【選択図】 図２