| abstract |
Provided is a lithium ion secondary battery capable of achieving both reduction in positive electrode resistance and ensuring battery durability. A lithium ion secondary battery includes a positive electrode including a positive electrode active material having an olivine structure, a negative electrode including a negative electrode active material, and a non-aqueous electrolyte that is a medium interposed between the positive electrode and the negative electrode. And a separator 12 disposed between the positive electrode 10 and the negative electrode 11, and an outer case 13 including the positive electrode 10, the negative electrode 11, the nonaqueous electrolyte, and the separator 12 therein. The separator 12 is subjected to a drying process. The positive electrode 10 contains an amount of water included in the range of 750 ppm to 1200 ppm with respect to the weight of the positive electrode 10. [Selection] Figure 1 |