NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

To suppress a decrease in output after high-rate charging/discharging.SOLUTION: The average bending ratio is 1.5 to 2.5 in the cross section parallel to the thickness direction of a negative electrode active material layer. The average bending ratio is calculated by the formula "R=B/A". In the formula, "R" indicates the average bending ratio. "B" indicates the average value of the length of the shortest path extending from the contact point between a negative electrode base material and a negative electrode active material particle to the surface of the negative electrode active material layer along the contour lines of the plurality of negative electrode active material particles. "A" indicates the average value of the thickness of the negative electrode active material layer.SELECTED DRAWING: Figure 9 【課題】ハイレート充放電後の出力の低下を抑えること。【解決手段】負極活物質層の厚さ方向に平行な断面において、平均屈曲比が１．５から２．５である。平均屈曲比は式「Ｒ＝Ｂ／Ａ」により算出される。式中、「Ｒ」は、平均屈曲比を示す。「Ｂ」は、負極基材と負極活物質粒子との接点を始点として、複数個の負極活物質粒子の輪郭線に沿って負極活物質層の表面まで延びる、最短経路の長さの平均値を示す。「Ａ」は、負極活物質層の厚さの平均値を示す。【選択図】図９