NOVELTY - An electrolyte liquid contains a solvent and an electrolyte salt. The solvent contains cyclic carbonate ester derivative having halogen atom and at least one type of sulfur containing compound.    USE - For battery (claimed) such as secondary battery, for portable electronic devices such as notebook type portable computer, mobile telephone, camcorder (video tape recorder).    ADVANTAGE - The cyclic carbonate ester derivative having halogen atom and sulfur containing compound are used in the electrolyte liquid, hence the chemical stability of the battery formed using the electrolyte liquid is improved. The battery has improved battery characteristics such as high temperature characteristic.    DETAILED DESCRIPTION - An electrolyte liquid contains a solvent and an electrolyte salt. The solvent contains cyclic carbonate ester derivative having halogen atom and at least one type of sulfur containing compounds of formulae (1-7).    R1-R4=halogen, alkyl, alkenyl, alkynyl, aryl, alkoxy or at least one portion of hydrogen in these groups is optionally substituted by substituent;    R5=alkyl, alkenyl, alkynyl, aryl, alkoxy or at least one portion of hydrogen in these groups is optionally substituted by substituent;    R6,R7=alkyl, alkenyl, alkynyl, aryl or at least one portion of hydrogen in these groups is optionally substituted by substituent;    R8,R10-R12=halogen, alkyl, alkenyl, alkynyl, aryl, alkoxy or at least one portion of hydrogen in these groups is optionally substituted by substituent;    R9,R13,R14=alkylene or at least one portion of hydrogen in the group is optionally substituted by substituent;    R15,R17=halogen, alkyl, alkenyl, alkynyl, aryl, alkoxy or -N(R18)(R19);    R18,R19=alkyl; and    R16=divalent coupling group.    An INDEPENDENT CLAIM is included for battery.    DESCRIPTION OF DRAWING(S) - The figure shows the sectional drawing of structure of secondary battery formed using the electrolyte liquid. (Drawing includes non-English language text)    Battery can (11)    Battery cover (14)    Anode (21)    Cathode (22)    Separator (23)