| abstract |
An object of the present invention is to maintain a large initial capacity even after repeated charging / discharging in a high-temperature environment of, for example, about 60 ° C. with a large capacity and a high output, while maintaining an output at room temperature and a low temperature of, for example, about −30 ° C. To provide a non-aqueous electrolyte lithium ion secondary battery that can prevent a decrease in output and can exhibit an initial high output. A non-aqueous electrolyte comprising a positive electrode 2 containing a positive electrode active material, a negative electrode 3 containing a negative electrode active material made of a carbon-based material, and an electrolyte containing LiPF 6 as a main component in a non-aqueous solvent. Is a non-aqueous electrolyte lithium ion secondary battery 1. The positive electrode active material is mainly composed of lithium iron phosphate having an olivine structure. The non-aqueous solvent is mainly composed of a mixed solvent of ethylene carbonate and diethyl carbonate or a mixed solvent of ethylene carbonate and ethyl methyl carbonate, and further contains at least vinylene carbonate and / or vinyl ethylene carbonate in an amount of 0.2% by weight to 5% by weight. contains. [Selection] Figure 1 |