Nowadays, lithium-ion batteries are used in a wide range of fields due to their high density/high power strengths compared to conventional nickel/hydrogen secondary batteries. Optimizing the parameters of a battery cell is known to be an effective way to improve battery performance. This study presents a specific energy density optimization method for a lithium-ion battery cell using a micro-genetic algorithm. As a result of the optimization, the specific energy density was improved by 26.7%.