| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery which never reduces in capacity, nor worsens in current collector foil strength and degradation feature even in the case of using an electrode shaped in a thin film.SOLUTION: In a lithium ion secondary battery, a positive electrode mixture layer includes a positive electrode active material A expressed by LiNiCoMnO(x≥0.8, and x+y+z=1), and a positive electrode active material B expressed by LiNiCoMnO(x≤0.6, and x+y+z=1). The weight percentage of the positive electrode active material A to the total weight of the positive electrode active material A and the positive electrode active material B is in a range of 60-90 wt%. The average particle diameter (D50_A) of the positive electrode active material A is equal to or smaller than one half of the thickness of the positive electrode mixture layer on one side thereof. The cumulative 90%-particle size (D90_A) of the positive electrode active material A is equal to or smaller than the one-side thickness of the positive electrode mixture layer. The D50_A, and the average particle diameter (D50_B) of the active material B satisfy the following expression: D50_A>D50_B.SELECTED DRAWING: Figure 2 |
