NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery securing safety. SOLUTION: This nonaqueous electrolyte secondary battery includes a positive electrode and a negative electrode, and has positive electrode active material containing an olivine structure phosphorous compound including at least Li and Fe. At least one of the positive electrode and the negative electrode has a characteristic that electric conductivity thereof significantly change by electrochemical doping and de-doping and the nonaqueous electrolyte secondary battery has conductive modifier to cut off electric current flowing therein with the reduction of the electric conductivity. It is thought that the conductive modifier secures safety in over charging conditions and the positive electrode active material containing a phosphoric compound secures safety under a high temperature environment respectively. Accordingly, the nonaqueous electrolyte secondary battery having extremely high safety can be provided.