Abstract: Provided is a lithium ion secondary battery including: a positive electrode; a negative electrode; a separator; and an electrolyte solution, the electrolyte solution including an additive A containing sulfur, and at least one of a cyclic carbonate additive B which is different from the additive A and which has an unsaturated bond and a cyclic carbonate additive C which is different from the additives A and B and which has a halogen. A molar ratio of the additive A relative to a total molar amount of the additive A, the additive B, and the additive C is smaller than a total of a molar ratio of the additive B and a molar ratio of the additive C relative to the total molar amount.

Abstract: The present invention provides a non-aqueous electrolyte secondary battery with various improved battery characteristics and a method for manufacturing such a non-aqueous electrolyte secondary battery. In the present invention, the battery manufacturing method includes accommodating and sealing a flat battery element (4) in which a positive electrode plate (41) and a negative electrode plate (42) stacked together via a separator (43), together with a non-aqueous electrolyte including a surplus electrolyte and at least one kind of electrolyte additive, in a laminate film exterior member (5), and then, subjecting the thus-assembled battery (1) to charging operation including at least initial charging in a state where a pressure is applied to a flat surface of the battery element from the outside of the exterior member (5).

Abstract: Provided is a lithium ion secondary battery including: a positive electrode; a negative electrode; a separator; and an electrolyte solution, the electrolyte solution including an additive A containing sulfur, and at least one of a cyclic carbonate additive B which is different from the additive A and which has an unsaturated bond and a cyclic carbonate additive C which is different from the additives A and B and which has a halogen. A molar ratio of the additive A relative to a total molar amount of the additive A, the additive B, and the additive C is smaller than a total of a molar ratio of the additive B and a molar ratio of the additive C relative to the total molar amount.

Abstract: The present invention provides a non-aqueous electrolyte secondary battery with various improved battery characteristics and a method for manufacturing such a non-aqueous electrolyte secondary battery. In the present invention, the battery manufacturing method includes accommodating and sealing a flat battery element (4) in which a positive electrode plate (41) and a negative electrode plate (42) stacked together via a separator (43), together with a non-aqueous electrolyte including a surplus electrolyte and at least one kind of electrolyte additive, in a laminate film exterior member (5), and then, subjecting the thus-assembled battery (1) to charging operation including at least initial charging in a state where a pressure is applied to a flat surface of the battery element from the outside of the exterior member (5).