| 摘要 |
Disclosed is a lithium ion secondary battery having low internal resistance and excellent load characteristics, wherein capacity decrease due to repeated charges and discharges is small. Specifically disclosed is a lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte solution. This lithium ion secondary battery is characterized in that the positive electrode and the negative electrode are respectively obtained by bonding an active material layer containing an electrode active material and a binder with a collector, a binder used in at least one of the positive electrode and the negative electrode contains polymer particles, and the polymer particles satisfy the following physical properties. A sheet-like molded body obtained by press-molding only the polymer particles has a swelling degree of 5-50% for the electrolyte solution, and the lithium ion conductivity of the sheet-like molded body swelled with the electrolyte solution is not less than 1 x 10-4 S.cm. |
