This study evaluates the feasibility of a passive phase change material (PCM)-based battery thermal management system intended for use in non-road mobile machines (NRMM). Two 3P4S modules, each with a nominal energy of 200 W h, were assembled from high-power cylindrical NCA Li-ion cells: one module was filled with a commercial paraffin PCM and the other was a reference without PCM. The modules were cycled at 1C, 1.5C, and 2C under identical ambient conditions, and module temperatures were recorded during charge and discharge. The results show that the PCM exhibits distinct thermal behavior at different C-rates. At 1C, the sensible heat of the solid PCM is sufficient to limit the temperature rise of the module. At 1.5C, the module temperature reaches the PCM melting point and remains approximately constant. At 2C, practically all PCM melts, which delays the temperature rise but its effect is constrained by the poor thermal conductivity of the organic PCM. The added PCM mass reduced the module gravimetric energy density from 231 W h kg−1 to 146 W h kg−1. Nevertheless, the results indicate that paraffin-based passive PCM thermal management can effectively limit temperature rise and improve the thermal behavior of high-power NCA battery modules at moderate C-rates, while still maintaining a competitive system-level energy density for small-scale