Evaluation and improvement of high-speed impact resistance of thermal batteries inside projectile: gas gun test simulation analyses

Thermal batteries integrated into projectiles must withstand extreme inertial loads during launch. Here, we develop a system-level finite element (FE) model of a thermal battery assembly (case–insulator–cell stack) and validate its impact response against gas-gun test data acquired from an instrumented projectile. The validated model is then used to elucidate load-transfer pathways and deformation modes under high-velocity impact against both deformable (Pb) and rigid targets. Rather than explicitly modeling fracture, we adopt deformation-based damage indicators (case bulging, header-lid indentation, and terminal-pin detachment propensity) to quantify structural vulnerability relevant to functional safety. Based on the mechanistic findings, we propose practical design directions—including tailored case-wall geometry, higher-strength case materials, and impact-mitigating buffer concepts—to reduce peak inertial loading and suppress critical deformation modes. This framework provides a quantitative route for impact-resistance design of thermal battery assemblies while reducing reliance on extensive gas-gun test campaigns.