| abstract |
The invention discloses a lithium ion secondary battery, comprising a battery core and an electrolyte, the positive electrode active material of the battery core includes a lithium manganese-based positive electrode active material; the electrolyte includes a solvent, a lithium salt and an additive, and the additive Including vinylene carbonate; wherein, the weight percentage q of the electrolyte solution and the total weight of the positive active material layer in the battery core, the weight percentage content r of the vinylene carbonate in the electrolyte solution, the The compaction density s of the negative electrode active material layer in the battery cell and the weight percentage p of the manganese element in the positive electrode active material satisfy 0.05≤q·r·s/p≤6, where q, r, and p The unit of s is wt%, and the unit of s is g/cm 3 . The lithium ion secondary battery provided by the invention can simultaneously take into account higher safety performance, cycle performance and storage performance. |