NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND BATTERY PACK

摘要

A nonaqueous electrolyte secondary battery of an embodiment includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The electrolyte contains an organic solvent with a lithium salt dissolved therein and an additive. An active material of the negative electrode contains at least one metal selected from Si and Sn, at least one or more selected from an oxide of the metal and an alloy containing the metal, and a carbonaceous matter. A fluorine concentration of a film A formed on the metal, the oxide of the metal, or the alloy containing the metal in the negative electrode active material is higher than a fluorine concentration of a film B formed on the carbonaceous matter, the additive includes at least one compound containing fluorine and at least one compound containing no fluorine, or an electrolyte after initial charge contains at least one fluorine-containing additive.

主权项

1. A nonaqueous electrolyte secondary battery comprising:
a positive electrode containing at least a positive electrode active material; a negative electrode containing at least a negative electrode active material; and a nonaqueous electrolyte, wherein the nonaqueous electrolyte contains an organic solvent with a lithium salt dissolved therein and an additive, and the negative electrode active material contains at least one metal selected from Si and Sn, at least one or more selected from an oxide of the metal and an alloy containing the metal, and a carbonaceous matter, and wherein a fluorine concentration of a film A formed on the metal, the oxide of the metal, or the alloy containing the metal in the negative electrode active material is higher than a fluorine concentration of a film B formed on the carbonaceous matter, the additive includes at least one compound containing fluorine and at least one compound containing no fluorine, or an electrolyte after initial charge contains at least one fluorine-containing additive.