| abstract |
The purpose of the present invention is to provide a nonaqueous electrolyte which can improve desired aspects of battery performance in particular in an acetonitrile electrolyte, a nonaqueous secondary battery, a cell pack, and a hybrid system. This nonaqueous electrolyte is characterized by containing a nonaqueous solvent, a PO 2 F 2 anion, and a cyclic acid anhydride. This nonaqueous secondary battery comprises a positive electrode having a positive electrode active substance layer on one or both sides of a current collector, a negative electrode having a negative electrode active substance layer on one or both sides of a current collector, and a nonaqueous electrolyte, and is characterized in that the nonaqueous electrolyte contains acetonitrile and LiPO 2 F 2 , and in that the value calculated by dividing the bulk resistance at -30°C in FRA measurement by the internal resistance value is within the range 0.05-0.7. Further, the nonaqueous secondary battery is characterized in that the capacity retention rate, calculated by dividing the 5C discharge capacity by the 1C discharge capacity after a 4 hour storage test at 85°C, is greater than or equal to 70%. |