Developing efficient and lightweight battery enclosures is essential for enhancing the performance and sustainability of electric vehicles (EVs). This study investigates the application of 2D triangular lattice structures in battery enclosure design, aiming to achieve an optimal balance between structural rigidity and weight reduction. A combination of closed-form analytical solutions and finite element analysis was employed to evaluate the bending behavior, effective rigidity, and rigidity-to-weight ratio of lattice plates with varying densities. The results indicate that while increased lattice density enhances rigidity, it also leads to higher weight, impacting overall efficiency. The 40% lattice density configuration achieved the highest weight reduction (27.64%) while maintaining a superior rigidity-to-weight ratio, confirming its effectiveness in lightweight structural applications. Additionally, the study highlights the increasing deviation between theoretical and numerical results at higher densities, emphasizing the necessity of numerical validation in lattice-based designs. The findings demonstrate the feasibility of using 2D lattice structures as high-performance, weight-efficient alternatives for EV battery enclosures, contributing to improved energy efficiency and vehicle dynamics in EV applications.