| abstract |
PROBLEM TO BE SOLVED: To provide a thin lithium-ion secondary battery which can be formed into a thin structure with a thickness of 3 mm or less while maintaining excellent current discharge characteristics and low-temperature discharge characteristics while having excellent capacity and cycle performance. The purpose is to: SOLUTION: This is a thin lithium ion secondary battery comprising a non-aqueous electrolyte and an electrode group 2 in which a positive electrode 5, a negative electrode 8, a separator 10 disposed between the positive electrode and the negative electrode are stacked, 10 is polyethylene having a heat shrinkage of 20% or less when present at 120 ° C. for 1 hour, and has a configuration in which at least one end of the separator 10 extends from the positive electrode and the negative electrode. A thin lithium ion secondary battery in which the thickness of the exterior material is in the range of 50 to 300 μm. |