TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compositions: Film containing sulfur atom is derived from sulfonic acid compound included in non-aqueous electrolyte, and film containing boron atom and/or phosphorus atom is derived from oxalate complex compound included in non-aqueous electrolyte. Non-aqueous electrolyte contains gas forming agent which decomposes when predetermined battery voltage is exceeded and may generate gas, and battery case has electric current interruption mechanism which operates when pressure within the battery case rises with the generation of the gas. Amount of gas forming agent in non-aqueous electrolyte is 200-250 mu mol of unit surface area (1 m2) contact of the positive electrode active material. Oxalate complex compound is lithium bisoxalatoborate (LiB(C2O4)2), lithium difluorobis(oxalato)phosphate (LiPF2(C2O4)2), lithium difluorooxalatoborate (LiBF2(C2O4)), and/or lithium tetrafluorooxalatophosphate (LiPF4(C2O4)). Preferred Parameters: Brunauer-Emmett-Teller (BET) specific surface area of negative electrode active material is 2.5-3.5 m2/g. BET specific surface area of positive electrode active material is 0.7-1.3 m2/g. Preferred Processes: The 1st charge treatment process includes constant current charge treatment process which charges at charge rate of 0.5-2 C to predetermined voltage set within the range of the voltage and constant voltage charge treatment process which carries out definite period of time charge with the predetermined voltage.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compositions: Sulfonic acid compound is 2-butyne-1,4-diol di(methane sulfonate). Amount of sulfonic acid compound in non-aqueous electrolyte is prepared so that it may be set to 3-8 mu mol of unit surface area (1 m2) contact of the positive electrode active material, and amount of oxalate complex compound in non-aqueous electrolyte is prepared so that it may be set to 2-10 mu mol of unit surface area (1 m2) contact of the negative electrode active material.