Material Selection for Battery Cell Casings Based on LCA and Steady‑State Thermal Performance (Comparative Analysis)

Abstract

This study evaluates eight materials for 18650 cylindrical battery casings by coupling a cradle‑to‑gate Life Cycle Assessment (LCA, A1–A3) with a steady‑state radial heat‑transfer model that integrates thin‑wall conduction and external convection. Candidates include Ni‑plated low‑carbon steel, stainless steel 304, aluminum 6061, high‑recycled aluminum (70% secondary content), polypropylene, polycarbonate, GFRP, and CFRP. Minimum wall thickness is set by a 0.5 MPa design pressure with a safety factor of 2 (≥0.15 mm for metals; 0.7 mm for polymers/composites). Simulations at a 5 W heat load for h = 50 W/m²K (forced) and h = 10 W/m²K (natural) show that external convection dominates total thermal resistance; under forced convection, ΔT spans 26.7–29.9 K with <1% variation among metals. From the LCA, per‑casing carbon footprints range from ≈6.4 gCO₂e (Ni‑plated steel) to ≈74 gCO₂e (CFRP). Pareto and MCDA place Ni‑plated steel and high‑recycled aluminum on the optimal frontier when ΔT, mass, and GWP are considered together. The key insight is that improving the convective coefficient (via airflow/interface design) is far more effective at lowering temperature than substituting casing materials, while material circularity (recycled content) delivers larger climate benefits than marginal conductivity gains.