The electrolytic solutions in the rechargeable lithium ion (Li-ion) batteries (consisting mainly of carbonate series) consist of organic solvents, electrolytes and additives. GC-MS systems are used effectively in the analysis of degraded components of electrolytic solutions during filling and discharging of batteries. This study involves the analysis of the gas released from a lithium ion battery which is kept at 80 ° C for 5 days.